WO2017217435A1 - Polyamide film and production method for same - Google Patents

Abstract

Provided are: a polyamide film that has excellent uniformity of thickness and excellent slipperiness and that has been effectively controlled for variations in physical properties in four directions; and a production method for the polyamide film. A polyamide film that is characterized by having all of characteristics (1)-(3). (1) The difference between the maximum value and the minimum value for the stress at 5% elongation during uniaxial tensile tests in four directions represented by 0 degrees, which is a specific direction from any point on the film, and 45 degrees, 90 degrees, and 135 degrees clockwise from said direction is 35 MPa or less. (2) The difference between the maximum value and the minimum value for the stress at 15% elongation during uniaxial tensile tests in the four directions is 40 MPa or less. (3) The coefficient of dynamic friction is 0.60 or less.

Description

Polyamide film and method for producing the same

The present invention relates to a novel polyamide film and a method for producing the same. Furthermore, this invention relates to the laminated body and container containing the said polyamide-type film.

Various resin films are made into various products such as packages by applying various processes. For example, a vinyl chloride film is used for a package (press-through pack) such as a medicine (tablet). For example, a polypropylene film is used in the case of packaging contents that require moisture resistance. In recent years, laminates obtained by laminating metal foils on resin films have been used for the purpose of imparting better gas barrier properties or moisture resistance from the viewpoint of maintaining the quality of contents. For example, a laminate composed of a base material layer (resin film) / metal foil layer (aluminum foil) / sealant layer is known.

In the industrial field, a metal can type has been the mainstream of the exterior material of a lithium ion battery, but there have been pointed out disadvantages such as a low degree of freedom in shape and difficulty in weight reduction. For this reason, it has been proposed to use a laminate composed of a base material layer / metal foil layer / sealant layer or a laminate composed of a base material layer / base material layer / metal foil layer / sealant layer as an exterior body. Such a laminated body is widely used because it is flexible and has a high degree of freedom in shape as compared to a metal can, and can be reduced in weight by thinning and can be easily reduced in size. ing.

¡Various performances are required for the laminate used in the above applications, and moisture resistance is a very important factor. However, a metal foil such as an aluminum foil that imparts moisture resistance is poor in spreadability and inferior in moldability. For this reason, using a polyamide-type film as a resin film which comprises a base material layer provides ductility, and has improved the moldability.

The moldability in this case is the moldability particularly when the film is cold-molded (cold processing). That is, when a product is produced by molding a film, the molding conditions are as follows: a) hot molding in which the resin is melted under heating and b) cold molding in which the resin is molded without melting. Although there is inter-molding, in the above-mentioned applications, moldability in cold molding (particularly drawing and overhanging) is required. Cold molding is a molding method that is more advantageous than hot molding in that it is superior in terms of production speed and cost because it does not have a heating step, and can draw out the original characteristics of the resin. For this reason, the development of a film suitable for cold forming is being promoted as a polyamide film.

As such a polyamide film, a stretched polyamide film is known (for example, Patent Documents 1 to 4). However, these polyamide-based films are produced by stretching by a tubular method. That is, not only is the productivity low, but the stretched film obtained is not sufficiently satisfactory in terms of thickness uniformity, dimensional stability, and the like. In particular, when the thickness of the film is uneven, if a laminated body of the film and the metal foil is to be processed by cold forming, a fatal defect such as a breakage of the metal foil or a pinhole may occur.

On the other hand, polyamide films stretched by the tenter method have also been proposed (for example, Patent Documents 5 to 12). The tenter method is advantageous in terms of productivity, dimensional stability and the like as compared with the tubular method.

Japanese Patent No. 5487485 Patent No. 52269942 JP2015-051525A JP2015-051527A Patent No. 5467387 JP 2011-162702 A JP 2011-255931 A JP2013-189614A Japanese Patent No. 5226941 JP 2013-22773 A International Publication WO2014 / 084248 Japanese Patent No. 3671978

However, even in a polyamide-based film stretched by the tenter method, there are still variations in physical properties (anisotropy) in each direction of the film. For this reason, it cannot be said that it has the performance which can fully be satisfied in the moldability at the time of performing cold forming (especially deep drawing).

The polyamide film 14 is manufactured by a process as shown in FIG. First, the melt-kneaded material 12 is prepared by melting the raw material 11 in the melt-kneading step 11a. The melt-kneaded material 12 is shape | molded by the shaping | molding process 12a to a sheet form, and the unstretched sheet 13 is obtained. Next, the polyamide-based film 14 is obtained by biaxially stretching the unstretched sheet 13 in the stretching step 13a. Further, this stretched polyamide film 14 is laminated in the cold forming step 15a as a secondary process after the laminated body 17 is produced through a laminating step 14a in which, for example, the metal foil layer 15 and the sealant film 16 are sequentially bonded. Various products 18 (for example, containers) are formed by processing the body 17 into a predetermined shape.

In such a stretched polyamide-based film 14, it is desirable to reduce variations in physical properties in each direction on the plane, but at least four directions at every 90 degrees (with any direction as a reference (0 degree)) In contrast, it is preferable to reduce variations in physical properties in the clockwise direction (a total of four directions of 45 degrees, 90 degrees, and 135 degrees). For example, in a biaxially stretched polyamide-based film, as shown in FIG. 4, if an MD (film flow direction) at the time of biaxial stretching is a reference direction (0 degree direction), centering on an arbitrary point A. (A) Reference direction (0 degree direction), (b) 45 degree direction clockwise with respect to MD (hereinafter referred to as “45 degree direction”), (c) 90 degree direction clockwise with respect to MD Direction (TD: direction perpendicular to the film flow direction) (hereinafter referred to as “90-degree direction”) and (d) 135 degrees in the clockwise direction with respect to MD (hereinafter referred to as “135-degree direction”). It is desirable to eliminate variations in physical properties in four directions.

When the laminate 17 including the stretched polyamide film 14 is subjected to the cold forming step 15a, since the polyamide film 14 is stretched in all directions, there is a variation in the physical properties in the four directions in the polyamide film 14, It becomes difficult to extend uniformly in all directions during cold forming. In other words, the presence of a direction that is easy to stretch and a direction that is difficult to stretch cause the metal foil to break or cause delamination or pinholes. When such a problem occurs, the function as a package or the like cannot be performed, which may lead to damage to the package (content). For this reason, it is necessary to reduce variations in physical properties in each direction as much as possible.

In this case, the thickness of the film is one of the physical properties that affect the moldability during cold forming. When a laminated body including a polyamide-based film having a variation in film thickness is cold-molded, there is a high possibility that a relatively thin portion is broken to cause a pinhole or cause delamination. For this reason, it is indispensable to uniformly control the thickness of the polyamide film used for cold forming throughout the film.

Here, with respect to the uniformity of the thickness of the polyamide-based film, the thickness accuracy of the polyamide-based film obtained by Patent Documents 3 to 10 above is better when stretched by the tenter method than by the tubular method. Is not fully satisfactory. That is, as described above, it is necessary to uniformly extend in four directions that are vertically and horizontally oblique at the time of cold forming, and therefore, it is necessary to have a sufficient thickness uniformity enough to withstand cold forming. In particular, as the film thickness becomes thinner (especially, a thickness of 15 μm or less), the influence of thickness uniformity on moldability becomes more prominent.

In general, the uniformity of the thickness of the film is easier to ensure as the thickness increases, so it may be possible to design the film to be relatively thick in order to ensure the uniformity of the thickness. However, in recent years, polyamide-based films and laminates used for cold forming have come to be widely used mainly for lithium-ion battery exterior materials, which further increases the output and size of batteries. With the demand for cost reduction, etc., it is required to make the polyamide film thinner. However, if the thickness is reduced, it is difficult to ensure the uniformity of the thickness.

As described above, although it is desired to develop a polyamide-based film that has excellent thickness uniformity and relatively small variation in physical properties in the four directions even though it is thinner, such a film has yet to be developed. There is no current situation.

Furthermore, as a physical property that affects the moldability during cold forming, there is a slip property of the film. For example, in the case of cold molding a laminate having a polyamide film as the outermost layer, the polyamide film and the molding die are in contact with each other, so that the polyamide film is difficult to slip (that is, the friction coefficient is large). When the mold is pushed in, wrinkles are generated on the surface of the laminated body, or the laminated body is likely to cause delamination. And since it becomes difficult to shape | mold the whole laminated body uniformly, we are anxious about generation | occurrence | production of a pinhole. In particular, when performing cold forming under high humidity, these problems become even more remarkable.

Therefore, the main object of the present invention is to provide a polyamide film excellent in thickness uniformity, effectively suppressing variations in physical properties in the four directions, and excellent in slipperiness, and a method for producing the same. There is to do.

As a result of intensive studies in view of the problems of the prior art, the present inventor has found that a film stretched by a special method using a specific raw material can achieve the above object, and has completed the present invention. It was.

That is, this invention relates to the following polyamide-type film and its manufacturing method.
1. A polyamide film having the following characteristics (1) to (3):
(1) Each stress at 5% elongation by a uniaxial tensile test in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction from an arbitrary point on the film. The difference between the maximum and minimum values is 35 MPa or less,
(2) In the above four directions, the difference between the maximum value and the minimum value of each stress at 15% elongation by uniaxial tensile test is 40 MPa or less, and (3) the dynamic friction coefficient is 0.60 or less. A polyamide-based film characterized by that.
2. 2. The polyamide-based film according to item 1, wherein the arithmetic average height Sa is 0.01 to 0.15 μm.
3. With respect to an average thickness in eight directions of 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees in a clockwise direction with respect to a certain direction from an arbitrary point on the film. Item 2. The polyamide film according to Item 1, wherein the standard deviation is 0.200 µm or less.
4). Item 2. The polyamide film according to Item 1, wherein the average thickness is 16 µm or less.
5). Item 2. The polyamide film according to Item 1, wherein the polyamide film contains at least one of an organic lubricant and an inorganic lubricant.
6). 2. A coated film comprising the polyamide-based film according to item 1 and an easy-adhesive coat layer and / or a slippery coat layer formed on the film.
7). Item 7. A laminate comprising the film according to item 1 or 6 and a metal foil laminated on the film.
8). The container containing the laminated body of said claim | item 7.
9. A method for producing a polyamide film comprising:
(1) A sheet forming step of obtaining an unstretched sheet by forming a melt-kneaded material containing a polyamide resin and at least one of an organic lubricant and an inorganic lubricant into a sheet shape,
(2) including a stretching step of obtaining a stretched film by biaxially stretching the unstretched sheet sequentially or simultaneously in MD and TD, and
(3) the following formulas a) and b);
a) 0.85 ≦ X / Y ≦ 0.95
b) 8.5 ≦ X × Y ≦ 9.5
(However, X represents the draw ratio of MD and Y represents the draw ratio of TD.)
A method for producing a polyamide-based film.
10. The stretching process is sequential biaxial stretching,
(2-1) a first stretching step for obtaining a first stretched film by stretching the unstretched sheet into MD at a temperature of 50 to 120 ° C. and (2-2) the first stretch step at a temperature of 70 to 150 ° C. The manufacturing method of said claim | item 9 including the 2nd extending process which obtains a 2nd stretched film by extending | stretching 1 stretched film to TD.
11. Item 11. The manufacturing method according to Item 10, wherein the first stretching step is stretching using a roll, and the second stretching step is stretching using a tenter.
12 Item 11. The method according to Item 10, wherein the second stretched film is further subjected to relaxation heat treatment at a temperature of 180 to 230 ° C.

The polyamide-based film of the present invention is excellent in thickness uniformity and excellent in stress balance at the time of elongation in four directions consisting of 0 degree direction, 45 degree direction, 90 degree direction and 135 degree direction with reference to an arbitrary direction, and Excellent slipperiness can also be exhibited.

For this reason, for example, in a laminate obtained by laminating the film of the present invention and a metal foil, the metal foil has good spreadability, and when performing cold drawing (particularly deep drawing or stretch forming). In addition, breakage, wrinkles, delamination, pinholes and the like of the metal foil can be effectively suppressed or prevented, and a highly reliable high quality product (molded product) can be obtained.

In particular, the polyamide-based film of the present invention has excellent thickness uniformity and excellent balance of stress when stretched in the four directions, even if it is very thin, for example, about 15 μm or less. Thereby, the laminated body which laminated | stacked this film and metal foil can obtain the product reduced in size with high output by cold forming, and becomes advantageous also in cost.

Moreover, according to the production method of the present invention, a polyamide-based film having the above excellent characteristics can be produced efficiently and reliably. In particular, even a very thin film having a thickness of about 15 μm or less can provide a film having excellent thickness uniformity. And when extending | stretching at comparatively low temperature, as a result of maintaining the original characteristic of resin more effectively, the film and laminated body more suitable by cold forming can be provided.

It is a schematic diagram which shows the outline | summary of the manufacturing process and cold working process of the polyamide-type film of this invention. It is a schematic diagram which shows the process by which an unstretched sheet is extended | stretched by sequential biaxial stretching which concerns on the manufacturing method of this invention. It is a figure which shows the state which looked at the extending | stretching process by a tenter from the a direction of FIG. It is a figure which shows the direction which measures the stress in a film. It is a figure which shows the sample for measuring the stress in a film. It is a figure which shows the method of measuring the average thickness in a film. It is a figure which shows the layer structure which concerns on embodiment of the laminated body of this invention. It is a figure which shows the layer structure which concerns on another embodiment of the laminated body of this invention.

1. Polyamide film The polyamide film of the present invention (the film of the present invention) has the following characteristics (1) to (3):
(1) Each stress at 5% elongation by a uniaxial tensile test in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction from an arbitrary point on the film. The difference between the maximum value and the minimum value (A value) is 35 MPa or less,
(2) In the above four directions, the difference (B value) between the maximum value and the minimum value of each stress at 15% elongation in a uniaxial tensile test is 40 MPa or less, and (3) the dynamic friction coefficient is 0.60 or less. It is characterized by satisfying everything.

(A) Material and composition of the film of the present invention (A-1) Polyamide resin The film of the present invention is a film mainly composed of a polyamide resin. The polyamide resin is a polymer formed by amide bonding of a plurality of monomers, and representative examples thereof include 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 12-nylon, Examples thereof include poly (metaxylene adipamide). Also, for example, a copolymer of two or more such as 6-nylon / 6,6-nylon, 6-nylon / 6,10-nylon, 6-nylon / 11-nylon, 6-nylon / 12-nylon is used. be able to. Mixtures of these can also be used. Among these, a) 6-nylon homopolymer, b) copolymer containing 6-nylon, or c) a mixture thereof is particularly preferable from the viewpoint of cold moldability, strength, cost and the like.

The number average molecular weight of the polyamide resin is not particularly limited and can be changed according to the kind of the polyamide resin to be used. However, it is usually preferably about 10,000 to 40,000, particularly 15,000 to 25,000. By using a polyamide resin within such a range, it becomes easy to stretch even at a relatively low temperature. As a result, crystallization that may occur when stretching at a relatively high temperature, resulting in a decrease in cold formability, etc. It can be avoided reliably.

The content of the polyamide resin in the film of the present invention is usually preferably 90% by mass or more, more preferably 95% by mass or more, and most preferably 98 to 99% by mass.

(A-2) Organic lubricant and inorganic lubricant (both are collectively referred to as “lubricant”)
The film of the present invention preferably contains at least one of an organic lubricant and an inorganic lubricant (particularly both an organic lubricant and an inorganic lubricant). By including these lubricants in the film, it becomes possible to increase the slipperiness more effectively. In particular, the dynamic friction coefficient and the arithmetic average height can be controlled within the optimum range. Moreover, in this invention, in order to improve the slip property of a film more, it is preferable to contain both an organic lubricant and an inorganic lubricant in a polyamide-type film. Also when using both together, it is preferable to make each content into the range of each content shown below.

The method of containing the lubricant in the film of the present invention is not particularly limited, and examples thereof include a method of previously containing the raw material polyamide resin, a method of directly adding to the extruder during kneading, and the like. Any one of these methods may be employed, or two or more methods may be used in combination.

Organic lubricant The organic lubricant is not particularly limited, for example, various organic lubricants such as hydrocarbons, fatty acids, aliphatic bisamides, metal soaps, and resins such as phenol resins, melamine resins, and polymethyl methacrylate resins. Organic lubricants of the system. In the present invention, an organic lubricant (for example, a melting point of 150 ° C. or lower) that can be melted by itself at the time of melt kneading with a polyamide resin component is preferable, and an aliphatic bisamide lubricant or the like can be suitably used as such an organic lubricant.

The number of carbon atoms of the bisamide composed of the fatty acid in the aliphatic bisamide lubricant is usually preferably in the range of 8-20, more preferably 12-18, and most preferably 16-18. preferable. When the number of carbon atoms exceeds 20, although the effect of improving slipperiness is sufficient up to the high humidity region, the adhesion with the easy-adhesion layer may be reduced, or the adhesion with the adhesive during lamination may be reduced. There is. In addition, when the number of carbon atoms is less than 8, sufficient slipperiness may not be obtained.

Examples of the carboxylic acid that can constitute the aliphatic bisamide having such a carbon number include saturated fatty acids such as stearic acid and behenic acid, and unsaturated fatty acids such as oleic acid and erucic acid.

As the aliphatic amides based on these carboxylic acids, known ones or commercially available products can be used. For example, stearic acid amide, behenic acid amide, erucic acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, ethylene bis behenic acid amide, ethylene biserucic acid amide, etc. ethylene bisamide, hexamethylene bis stearic acid amide, hexa Mention may be made of hexamethylene bisamides such as methylene bisoleic acid amide hexamethylene bisbehenamide and hexamethylene biserucamide. Among these, a lubricant containing at least one of ethylene bisstearic acid amide and ethylene bisbehenic acid amide is particularly preferable in terms of excellent compatibility with the polyamide-based resin.

As the organic lubricant, a powdery one can be used under normal temperature and normal pressure, but in the present invention, the organic lubricant is dissolved at the time of melt-kneading, so the particle size is not particularly limited.

The content of the organic lubricant in the polyamide film is usually preferably 0.02 to 0.25% by mass, and more preferably 0.03 to 0.15% by mass. When content of an organic lubricant is less than 0.02 mass%, there exists a possibility that the effect which improves slipperiness cannot fully be acquired. On the other hand, when the content of the organic lubricant exceeds 0.25% by mass, the excess organic lubricant bleeds out to the film surface, thereby reducing the adhesiveness of the adhesive and the printing ink. When the adhesive force is lowered, particularly, the cold formability may be deteriorated. In the present invention, it is desirable that the content of the organic lubricant is a total content of at least one aliphatic bisamide lubricant.

Inorganic lubricant As the inorganic lubricant in the present invention, for example, silicon dioxide, clay, talc, mica, calcium carbonate, zinc carbonate, wollastonite, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, magnesium aluminosilicate, Examples include zinc oxide, antimony trioxide, zeolite, kaolinite, hydrotalcite, and oxide glass. Among these, silicon dioxide is particularly preferable.

The inorganic lubricant is usually in the form of a powder, but the average particle size is generally preferably 0.5 to 4.0 μm. When the average particle size is less than 0.5 μm, the effect of roughening the film surface is small, and the effect of improving the slipperiness cannot be sufficiently obtained. On the other hand, when the average particle diameter exceeds 4.0 μm, the transparency may be deteriorated.

The particle shape of the inorganic lubricant is not particularly limited, and may be any of spherical shape, flake shape, irregular shape, balloon shape (hollow shape), and the like. Therefore, in the present invention, for example, glass beads, glass balloons and the like can also be used.

As the inorganic lubricant, inorganic lubricants having the same average particle diameter may be used, or two or more inorganic lubricants having different average particle diameters may be used.

The content of the inorganic lubricant in the polyamide film of the present invention is usually preferably 0.05 to 5% by mass, more preferably 0.1 to 4% by mass, and particularly 0.1 to 2% by mass. % Is more preferable. Therefore, for example, it can be 0.05 to 0.25% by mass. For example, it may be 0.09 to 0.20% by mass. When content of an inorganic lubricant is less than 0.05 mass%, there exists a possibility that the improvement effect of slipperiness by adding an inorganic lubricant may not fully be acquired. On the other hand, when the content of the inorganic lubricant exceeds 5% by mass, the film surface tends to be too rough, so that the arithmetic average height described later becomes too large and the ink adhesion decreases, or the transparency of the film. Therefore, it may be difficult to impart design properties by printing. Moreover, there is a possibility that winding deviation is likely to occur during film production. In the present invention, the content of the inorganic lubricant is silicon dioxide, clay, talc, mica, calcium carbonate, zinc carbonate, wollastonilo, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, magnesium aluminosilicate, The total content of at least one of glass balloon, zinc oxide, antimony trioxide, zeolite, kaolinite and hydrotalcite is desirable.

Ratio of organic lubricant to inorganic lubricant The ratio of organic lubricant to inorganic lubricant is not particularly limited and can be appropriately set according to the type of lubricant used, etc. Usually, the weight ratio of organic lubricant: inorganic lubricant = The ratio may be about 1: 0.1 to 1:70, preferably 1: 0.2 to 1:35, more preferably 1: 0.2 to 1: 5. Therefore, for example, the range of organic lubricant: inorganic lubricant = 1: 0.1 to 1:10 can be used. By setting within such a range, slipperiness can be more effectively imparted.

(A-3) Other components In the film of the present invention, components other than the polyamide resin and the lubricant may be contained within a range not impeding the effects of the present invention. For example, various additives such as pigments, antioxidants, ultraviolet absorbers, preservatives, antistatic agents, inorganic fine particles, as well as bending resistance pinhole improvers such as polyolefins, polyamide elastomers, polyester elastomers, etc. You may add 1 type, or 2 or more types.

In addition, examples of the method of adding various additives include a method of adding it to a polyamide resin as a raw material and a method of adding it directly to an extruder, and one of these methods is adopted. Alternatively, two or more methods may be used in combination.

(B) Physical properties of the film of the present invention The film of the present invention preferably has a biaxially oriented molecular orientation. Such a film can be basically obtained by biaxial stretching. In particular, a biaxially stretched film using a roll and a tenter is suitable. Such a film of the present invention is controlled so as to have the following physical properties.

(B-1) Stress characteristics The film of the present invention must satisfy the A value and the B value at the same time as an index indicating that the stress balance during elongation during secondary processing is very excellent. When the A value and the B value exceed the above ranges, the stress balance in all directions of the polyamide film is poor, and it becomes difficult to obtain uniform moldability. When uniform moldability cannot be obtained, for example, when cold-molding a laminate in which the film of the present invention and a metal foil are laminated, sufficient spreadability is not imparted to the metal foil (that is, the polyamide film is a metal foil). Therefore, the metal foil is likely to break, or problems such as delamination and pinholes are likely to occur.

The A value is usually 35 MPa or less, particularly 30 MPa or less, more preferably 25 MPa or less, and most preferably 20 MPa or less. The lower limit value of the A value is not limited, but is usually about 15 MPa.

The B value is usually 40 MPa or less, particularly 38 MPa or less, more preferably 34 MPa or less, and most preferably 30 MPa or less. The lower limit of the B value is not limited, but is usually about 20 MPa.

Further, the stress in the four directions at the time of 5% elongation is not particularly limited, but in terms of the cold formability of the laminate, any of them is preferably in the range of 35 to 130 MPa, and in the range of 40 to 90 MPa. More preferably, it is most preferably in the range of 45 to 75 MPa.

The stress in the four directions at the time of 15% elongation is not particularly limited, but in terms of the cold formability of the laminate, any of them is preferably in the range of 55 to 145 MPa, and in the range of 60 to 130 MPa. More preferably, it is most preferably in the range of 65 to 115 MPa.

In the film of the present invention, when the stress in the four directions at the time of 5% and 15% elongation does not satisfy the above range, sufficient cold formability may not be obtained.

The stress in the four directions in the film of the present invention is measured as follows. First, after adjusting the humidity of the polyamide film at 23 ° C. × 50% RH for 2 hours, as shown in FIG. 5, the arbitrary point A on the film is the center point, and the reference direction (0 degree direction) of the film is arbitrary. The measurement direction is 45 degrees (b), 90 degrees (c), and 135 degrees (d) clockwise from the reference direction (a), and from the center point A to each measurement direction. A sample that is cut into a strip shape of 100 mm and 15 mm in a direction perpendicular to the measurement direction is used. For example, as shown in FIG. 5, in the 0 degree direction, the sample 41 is cut out in the range of 30 mm to 130 mm from the center point A (vertical 100 mm × horizontal 15 mm). Cut the sample in the same way for the other directions. For these samples, using a tensile tester (AG-1S manufactured by Shimadzu Corporation) equipped with a 50N measurement load cell and a sample chuck, the stress at 5% and 15% elongation was obtained at a tensile speed of 100 mm / min. Measure each. In addition, said MD can be made into a reference direction when MD in the extending process at the time of film manufacture is known.

It is preferable that the polyamide film of the present invention satisfying the above characteristic values is obtained by a biaxial stretching method including a step in which at least one of the longitudinal direction and the transverse direction is stretched by a tenter.

Generally, as a biaxial stretching method, a simultaneous biaxial stretching method in which a longitudinal direction and a transverse direction are simultaneously performed, and a sequential biaxial stretching in which a longitudinal direction is performed and then a transverse direction is performed. There is a way. In the above description, the vertical direction is exemplified as the previous step, but in the present invention, either the vertical direction or the horizontal direction may be the first step.

The film of the present invention is preferably obtained by a sequential biaxial stretching method from the standpoint of flexibility in setting stretching conditions. Therefore, the film of the present invention is preferably obtained by sequential biaxial stretching including a step in which at least one of the longitudinal direction and the transverse direction is stretched by a tenter. In particular, the film of the present invention is desirably manufactured by the manufacturing method of the present invention described later.

(B-2) Coefficient of dynamic friction (sliding property)
The film of the present invention has a dynamic friction coefficient of 0.60 or less, and particularly preferably 0.50 or less, as an index indicating that it is excellent in formability (slidability) during cold forming. Therefore, for example, it can be set to 0.48 or less. By controlling the coefficient of dynamic friction to 0.60 or less, even when cold forming is performed in a high humidity environment (for example, a humidity of 90% or more), slipperiness is improved, for example, wrinkles, delamination, pinholes, etc. Etc. can be effectively suppressed or prevented. When the dynamic friction coefficient exceeds 0.60, the slipping property at the time of cold forming becomes insufficient, and particularly when cold forming is performed in a high humidity environment, wrinkles are generated or delamination is caused. Moreover, it becomes difficult to uniformly mold the entire laminate, and pinholes and the like are likely to occur. The lower limit value of the dynamic friction coefficient is not particularly limited, but is usually about 0.05. In addition, as for the dynamic friction coefficient in this invention film, the value measured by the following method should just satisfy the said range on the at least one surface of this invention film.

The measurement of the dynamic friction coefficient in the present invention was performed according to JIS K7125. More specifically, a polyamide film sample was conditioned at 23 ° C. × 50% RH for 2 hours, and then measured under the same temperature and humidity conditions. In the calculation of the dynamic friction coefficient, two samples are taken for each of the four directions specified during the measurement of the (B-1) stress characteristics, and a total of eight points are measured and the average value is obtained.

(B-3) Arithmetic mean height (surface roughness)
The film of the present invention has an arithmetic average height Sa (hereinafter simply referred to as “Sa”) of 0.01 to 1 as one index showing that it is excellent in formability (slidability) during cold forming. It may be about 0.30, preferably 0.01 to 0.25, more preferably 0.02 to 0.25, and even more preferably 0.03 to 0.25. Most preferred. Therefore, for example, it can be set in the range of 0.01 to 0.15. When Sa is less than 0.01, sufficient slipperiness cannot be obtained at the time of cold molding, so that there is a possibility that wrinkles, delamination, etc. may occur when the mold is pushed in at the time of cold molding. On the other hand, when Sa exceeds 0.30, although the slipperiness becomes good, the strength of the film may be lowered.

Sa measurement in the present invention was carried out using a Tailsurf CCI6000, an ultra-precision non-contact three-dimensional surface property measuring machine manufactured by Taylor Hobson. More specifically, a polyamide film sample was conditioned at 20 ° C. × 65% RH for 2 hours, and then measured under the same temperature and humidity conditions. In the case of a laminate including the film of the present invention as the outermost layer, the surface serving as the outermost layer was used as the measurement surface. The sample is cut into a size of 100 mm × 100 mm, 10 points are measured randomly (n = 10), and the average value is obtained.

(B-4) Average thickness and thickness accuracy
The film of the present invention has a standard deviation with respect to the average thickness in the following 8 directions as an index indicating that the thickness accuracy (thickness uniformity) is very high, usually 0.200 μm or less, particularly 0.180 μm. Or less, more preferably 0.160 μm or less. When the standard deviation indicating the thickness accuracy is 0.200 μm or less, the variation in the thickness of the film surface becomes very small. For example, even when the thickness of the film is about 15 μm or less, it is bonded to the metal foil. When the deep-drawing cold forming is carried out, no problems such as delamination and pinholes occur and good moldability can be obtained. When the standard deviation exceeds 0.200 μm, the thickness accuracy is low, and particularly when the film thickness is small, sufficient extensibility cannot be imparted to the metal foil when bonded to the metal foil, and delamination is caused. Or generation | occurrence | production of a pinhole becomes remarkable and favorable moldability may not be obtained.

The thickness accuracy evaluation method is performed as follows. After conditioning the polyamide film at 23 ° C. × 50% RH for 2 hours, as shown in FIG. 6, after specifying a reference direction (0 degree direction) with an arbitrary point A on the film as a center point, the center Reference direction (a) from point A, 45 degree direction (b), 90 degree direction (c), 135 degree direction (d), 180 degree direction (e), 225 degree direction (f ) Draw a total of eight straight lines L1 to L8 each having a length of 100 mm in eight directions of 270 degrees (g) and 315 degrees (h). On each straight line, the thickness is measured at intervals of 10 mm from the center point with a length gauge “HEIDENHAIN-METRO MT1287” (manufactured by HEIDENHAIN) (measured at 10 points). FIG. 6 shows a state in which measurement points (10 points) when measuring L2 in the 45 degree direction are taken as an example. And the average value of the measured value of 80 data total obtained by measuring in all the straight lines is calculated, this is made into average thickness, and the standard deviation with respect to average thickness is calculated. In addition, said MD becomes a reference direction when MD in the extending process at the time of film manufacture is known.

In the present invention, the average thickness and the standard deviation may be measured based on any one point (point A) of the polyamide film, but the polyamide film wound around the obtained film roll is particularly used. In any of the following three points, the average thickness and the standard deviation within the above range are more desirable. The three points are a) a position near the center of the winding width and half the winding amount, b) a position near the right end of the winding width and half the winding amount, and c) the winding. It is a position near the left end of the width and near the end of the winding.

In addition, the average thickness of the film of the present invention may be generally set within a range of 30 μm or less, but is particularly preferably set within a range of 25 μm or less. More specifically, it is preferably 16 μm or less, more preferably 15.2 μm or less, and most preferably 12.2 μm or less.

The film of the present invention is preferably a laminate to be bonded to a metal foil, and is preferably used for cold forming applications. Biaxial stretching using a tenter as described below is performed under specific conditions. Obtaining a biaxially stretched film excellent in thickness accuracy (thickness uniformity) and excellent in stress balance at the time of stretching in the four directions, even if the film is thin, by performing under satisfying stretching conditions. Can do.

When the average thickness of the film exceeds 30 μm, the moldability of the polyamide film itself is lowered, and it may be difficult to use it for a small battery outer packaging material, and there is a possibility that it may be disadvantageous in terms of cost. On the other hand, the lower limit of the thickness of the film is not particularly limited, but if the average thickness is less than 2 μm, impartability to the metal foil when bonded to the metal foil tends to be insufficient, and the moldability is poor. Usually, it may be about 2 μm.

The polyamide-based film of the present invention is a laminate that is bonded to a metal foil and is preferably used for cold forming applications. When the polyamide-based film of the present invention that satisfies the above characteristics is used, the metal foil Sufficient spreadability can be imparted. This effect improves moldability during cold forming (particularly during drawing (especially deep drawing)), prevents metal foil from breaking, and causes defects such as delamination and pinholes. Can also be suppressed or prevented.

As the thickness of the polyamide film decreases, it becomes difficult to impart sufficient spreadability to the metal foil. In particular, in an extremely thin film of 20 μm or less, the stress at the time of stretching varies, and the thickness accuracy is low, so that the polyamide film or the metal foil is significantly broken by the pressing force at the time of cold forming. In other words, the thinner the film, the greater the variation in stress when stretched, and the greater the variation in thickness, and thus a higher degree of control is required.

In this case, in a conventional manufacturing method using a tubular method or a tenter method, which is a general method for manufacturing a polyamide-based film, the thickness is 15 μm or less, and the variation in stress at the time of elongation is small. It is difficult to manufacture a product with high accuracy. This is also clear from the fact that, for example, in any of Patent Documents 1 to 10, only a minimum of 15 μm thickness of polyamide-based film described as a specific example is disclosed.

On the other hand, in the present invention, by adopting a specific manufacturing method as described later, even when the thickness is about 15 μm or less (particularly about 12 μm or less), the stress at the time of elongation in the above four directions. The present inventors have succeeded in providing a polyamide film having excellent balance and high uniformity of thickness. As a result of providing such a special polyamide-based film, when a laminate laminated with a metal foil is used, for example, for an exterior body of a battery (for example, a lithium ion battery), for example, the number of electrodes, the capacity of an electrolyte, etc. can be increased. In addition, the battery itself can be reduced in size and cost.

(B-5) Haze (transparency)
The film of the present invention preferably has a haze of 60% or less, more preferably 40% or less, more preferably 25% or less, and most preferably 10% or less in applications where transparency is required. preferable. Therefore, for example, it can be set to 8% or less. For example, it can be set to 6% or less. If the haze exceeds 60%, the transparency of the film is lost, and it may be difficult to impart design properties by printing. The lower limit of haze is not particularly limited, but is usually about 1.0%.

The measurement of haze in the present invention was carried out using a haze meter “NDH4000” manufactured by Nippon Denshoku Industries Co., Ltd. More specifically, a polyamide film sample was conditioned at 23 ° C. × 50% RH for 2 hours, and then measured under the same temperature and humidity conditions. In the case of a laminate including the film of the present invention as the outermost layer, the surface serving as the outermost layer was used as the measurement surface. The number of samples measured was n = 10, and the average value was taken.

(C) Laminate containing the film of the present invention The film of the present invention can be used for various applications in the same manner as known or commercially available polyamide-based films. In this case, the film of the present invention can be used as it is or after being surface-treated, and can also be used in the form of a laminate formed by laminating other layers.

When taking the form of a laminated body, the laminated body (laminated body of this invention) containing this invention film and the metal foil laminated | stacked on the film is mentioned as the representative example. In this case, this invention film and metal foil may be laminated | stacked so that it may contact | connect directly, and may be laminated | stacked in the state which interposed the other layer. In particular, in the present invention, a laminate in which the film of the present invention / metal foil / sealant film is laminated in this order is preferable. In this case, an adhesive layer may or may not be interposed between the respective layers.

For example, as shown in FIG. 7, a laminate 60 having a three-layer structure in which polyamide film 51 / adhesive layer 52 / metal foil 53 are laminated in this order can be mentioned. Further, for example, as shown in FIG. 8, a laminate 70 having a five-layer structure in which polyamide film 51 / adhesive layer 52a / metal foil 53 / adhesive layer 52b / sealant film 54 are laminated in this order may be mentioned. In any of these cases, as will be described later, various coat layers and the like may be appropriately interposed between the respective layers as required. When two or more adhesive layers are employed, the composition, thickness, etc. may be the same or different from each other.

The film of the present invention can be used as it is, but before the metal foil is laminated, a coating layer (particularly a wet coating layer) can be formed on the film of the present invention as needed. As the coating layer, at least one of a) an easy adhesion coating layer (primer layer or anchor coating (AC layer)) and b) an easy-sliding coating layer can be suitably employed. In addition, these coat layers are preferably formed by in-line coating. Also in the physical properties of a coated film in which a coating layer is formed on the film of the present invention, it is desirable to be within the range of the physical properties shown in the above “(B) Physical properties of the film of the present invention”. Details of each coat layer will be described later in <Embodiment of coat layer>.

Examples of the metal foil include metal foils (including alloy foils) containing various metal elements (aluminum, iron, copper, nickel, etc.), and pure aluminum foils or aluminum alloy foils are particularly preferably used. The aluminum alloy foil preferably contains iron (aluminum-iron-based alloy, etc.), and other components are publicly known as defined by JIS, etc. as long as the moldability of the laminate is not impaired. Any component may be included as long as the content is within the range.

The thickness of the metal foil is not particularly limited, but is preferably 15 to 80 μm, more preferably 20 to 60 μm from the viewpoint of moldability and the like.

As the sealant film that can constitute the laminate of the present invention, it is preferable to employ a thermoplastic resin having heat sealing properties such as polyethylene, polypropylene, olefin copolymer, and polyvinyl chloride. The thickness of the sealant film is not limited, but is usually preferably 20 to 80 μm, more preferably 30 to 60 μm.

In the laminate of the present invention, one or more other layers are laminated on the exterior side of the film of the present invention constituting the laminate (a surface different from the surface to be bonded to the metal foil) depending on the purpose of use. May be. Although it does not restrict | limit especially as another layer, For example, a polyester film is preferable. By laminating the polyester film, heat resistance, voltage resistance, chemical resistance and the like can be improved, and peel strength can also be increased.

The polyester is not particularly limited, and for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-2,6-naphthalate and the like are preferable. Among these, it is preferable to use PET from the viewpoint of cost and effect.

In the laminate of the present invention, an adhesive layer can be interposed between the layers. For example, it is desirable to laminate each layer using an adhesive layer such as a urethane adhesive layer or an acrylic adhesive layer between the polyamide film / metal foil and between the metal foil / sealant film.

In this case, when the polyamide-based film of the present invention has an easy-adhesion coat layer on at least one surface of the film surface, it is preferable that a metal foil is laminated on the easy-adhesion coat layer surface. More specifically, it is preferable that metal foil is laminated | stacked through adhesive layers, such as a urethane type adhesive layer and an acrylic adhesive layer, on the surface of an easily bonding coat layer.

Since the laminate of the present invention includes the film of the present invention, it can be suitably used for cold forming (particularly deep drawing or stretch forming). Here, the draw molding is basically a method of molding a bottomed container having a shape such as a cylinder, a rectangular tube, or a cone from a single laminate. Such containers are generally characterized by no seams.

(D) The container containing the laminated body of this invention This invention also includes the container containing the laminated body of this invention. For example, the container shape | molded using the laminated body of this invention is also included by this invention. Among these, it is preferable that it is a container obtained by cold forming. In particular, a container manufactured by drawing (drawing) or bulging (extension) as cold forming is preferable, and a container manufactured by pultrusion is particularly preferable.

That is, the container according to the present invention is a method for producing a container from the laminate of the present invention, and preferably comprises a method for producing a container comprising a step of cold forming the laminate. Can do. Therefore, for example, a seamless container can be produced from the laminate of the present invention.

The cold forming method itself in this case is not limited, and can be performed according to a known method. For example, what is necessary is just to employ | adopt the method of shape | molding as a solid, without fuse | melting resin contained in a laminated body. As long as these conditions are satisfied, the molding temperature (the temperature of the laminate) can be appropriately set according to the physical properties of the resin used (for example, the glass transition point). In general, the molding temperature is preferably 50 ° C. or lower, more preferably 45 ° C. or lower. Therefore, for example, cold molding can be performed after setting the molding temperature to room temperature (about 20 to 30 ° C.). For example, cold molding can be performed at a temperature below the glass transition point of the resin.

As a more specific molding method (processing method), for example, drawing such as cylindrical drawing, rectangular drawing, irregular drawing, conical drawing, pyramid drawing, ball head drawing, etc. can be preferably employed. . The drawing process is classified into a shallow drawing process and a deep drawing process, but the laminate of the present invention can be applied particularly to a deep drawing process.

These drawing processes can be carried out using a normal mold. For example, using a press machine including a punch, a die, and a blank holder, a) a step of placing the laminate of the present invention between the die and a blank holder, and b) deformation into a container shape by pushing the punch into the laminate. The drawing process can be performed by a method including a step of causing the drawing process.

The container obtained in this way can be highly reliable because defects such as metal foil breakage, delamination, and pinholes are effectively suppressed. For this reason, the container which concerns on this invention can be used for various uses including the packaging material of various industrial products. In particular, a molded body by deep drawing is suitably used for an exterior body of a lithium ion battery, and a molded body by overhang molding is suitably used for a press-through pack or the like.

<Embodiment of coat layer>
An easily adhesive coat layer and / or a slippery coat layer is suitable as a coat layer (particularly a layer formed by application of a coating solution) that can be formed in advance of laminating the metal foil on the polyamide film of the present invention. Can be used. These coat layers preferably have the following embodiments.

Easy-adhesive coat layer It is preferable to have an easy-adhesive coat layer (primer layer or anchor coat (AC layer)) on at least one whole surface or part of the surface of the film of the present invention. When forming such an easy-adhesion coat layer, applying an adhesive to the surface of the film having the easy-adhesion coat layer and bonding the metal foil together increases the adhesion between the polyamide film and the metal foil. Can do. Thereby, sufficient spreadability can be provided with metal foil. For this reason, in addition to the polyamide-based film or the metal foil becoming difficult to break, the occurrence of delamination or pinholes can be more effectively prevented.

Although the thickness of the easy-adhesion coat layer is not limited, it is usually preferably 0.01 to 0.10 μm, more preferably 0.02 to 0.09 μm. If the thickness of the easy-adhesion coat layer is less than 0.01 μm, it becomes difficult to form an easy-adhesion coat layer having a uniform thickness on the film. As a result, the effect of improving the adhesion between the polyamide film and the metal foil as described above is poor. On the other hand, when the thickness of the easy-adhesion coat layer exceeds 0.10 μm, the effect of improving the adhesion between the polyamide-based film and the metal foil is saturated, which is disadvantageous in cost.

As the easy adhesion coating layer, for example, a layer containing various synthetic resins such as polyurethane resin and acrylic resin can be adopted. In particular, an easy adhesion coating layer containing a polyurethane resin is preferable. As such a polyurethane resin, for example, an anionic water-dispersible polyurethane resin is preferably contained. The easy-adhesion coat layer containing this resin can be suitably formed, for example, by applying an aqueous coating material containing the resin to the surface of the polyamide film.

The polyurethane resin is a polymer obtained, for example, by a reaction between a polyfunctional isocyanate and a hydroxyl group-containing compound. More specifically, polyfunctional isocyanates such as aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane isocyanate, polymethylene polyphenylene polyisocyanate, or aliphatic polyisocyanates such as hexamethylene diisocyanate, xylene isocyanate, and polyether polyols, The urethane resin obtained by reaction with hydroxyl-containing compounds, such as polyester polyol, polyacrylate polyol, and polycarbonate polyol, can be illustrated.

The anionic water-dispersible polyurethane resin used in the present invention is obtained by introducing an anionic functional group into a polyurethane resin. Examples of a method for introducing an anionic functional group into a polyurethane resin include a) a method using an diol having an anionic functional group as a polyol component, and b) a method using a diol having an anionic functional group as a chain extender. Etc.

Examples of the diol having an anionic functional group include glyceric acid, dioxymaleic acid, dioxyfumaric acid, tartaric acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylolvaleric acid, and 2,2-dimethylolpentanoic acid. In addition to aliphatic carboxylic acids such as 4,4-di (hydroxyphenyl) valeric acid and 4,4-di (hydroxyphenyl) butyric acid, aromatic carboxylic acids such as 2,6-dioxybenzoic acid and the like can be mentioned.

When dispersing an anionic polyurethane resin in water, it is generally preferable to use a volatile base. The volatile base is not particularly limited, and a known volatile base can be used. More specifically, ammonia, methylamine, ethylamine, dimethylamine, diethylamine, triethylamine, morpholine, ethanolamine and the like are exemplified. Among these, triethylamine is more preferable in that the liquid stability of the water dispersible polyurethane resin is good and the residual amount in the easy-adhesion coat layer is small because the boiling point is relatively low.

Commercially available products can be used as the anionic water-dispersible polyurethane resin as described above. For example, “Hydran ADS-110”, “Hydran ADS-120”, “Hydran KU-400SF”, “Hydran HW-311”, “Hydran HW-312B”, “Hydran HW-333”, “Hydran” manufactured by DIC "AP-20", "Hydran AP-201", "Hydran APX-101H", "Hydran AP-60LM", "Superflex 107M", "Superflex 150", "Superflex 150HS" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. , “Superflex 410”, “Superflex 420NS”, “Superflex 460”, “Superflex 460S”, “Superflex 700”, “Superflex 750”, “Superflex 840”, Mitsui Chemicals Polyurethanes, Inc. “Bamboo rack W-6010”, “Bamboo rack W-6020”, “Bamboo rack W-511”, “Bamboo rack WS-6021”, “Bamboo rack WS-5000”, “NeoRez R9679”, “NeoRez R9637” manufactured by DSM, “NeoRez R966”, “NeoRez R972” and the like.

In the polyamide-based film of the present invention, it is preferable that a hardener such as melamine resin or carbodiimide is contained in the easy-adhesion coat layer for the purpose of improving the water resistance, heat resistance, etc. of the easy-adhesion coat layer. The content of the curing agent is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the anionic water-dispersible polyurethane resin.

A typical example of a melamine resin is tri (alkoxymethyl) melamine. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Various melamine resins can be used alone or in combination of two or more.

The carbodiimide compound is not particularly limited as long as it has at least two carbodiimide groups in the molecule. For example, compounds having a carbodiimide group such as p-phenylene-bis (2,6-xylylcarbodiimide), tetramethylene-bis (t-butylcarbodiimide), cyclohexane-1,4-bis (methylene-t-butylcarbodiimide) In addition, polycarbodiimide which is a polymer having a carbodiimide group may be mentioned. These can be used alone or in combination of two or more. Among these, polycarbodiimide is preferable from the viewpoint of ease of handling.

Known or commercially available carbodiimide compounds can be used. Moreover, the manufacturing method is not particularly limited. For example, in the case of polycarbodiimide, it can be suitably produced by a condensation reaction involving decarbonization of an isocyanate compound. The isocyanate compound is not limited, and may be any of aliphatic isocyanate, alicyclic isocyanate, aromatic isocyanate, and the like. The isocyanate compound may be copolymerized with polyfunctional liquid rubber or polyalkylene diol as necessary. In particular, as a commercially available product of polycarbodiimide, a carbodilite series manufactured by Nisshinbo Chemical Co., Ltd. can be suitably used. More specifically, the product names of water-soluble type “SV-02”, “V-02”, “V-02-L2”, “V-04” (all manufactured by Nisshinbo Chemical Co., Ltd.), organic solution type Product names “V-01”, “V-03”, “V-07”, “V-09”, solventless type “V-05” (all manufactured by Nisshinbo Chemical Co., Ltd.), etc. are preferably used. be able to.

The solid content concentration of the anionic water-dispersible polyurethane resin in the aqueous coating composition containing the anionic water-dispersible polyurethane resin can be appropriately changed depending on the specifications of the coating device, drying / heating device, etc. Then, the problem that a long time is required in the drying process is likely to occur. On the other hand, if the solid content concentration is too high, it is difficult to obtain a uniform coating agent, and this tends to cause problems in coating properties. From such a viewpoint, the solid content concentration of the anionic water-dispersible polyurethane resin in the aqueous coating material is preferably in the range of 3 to 30% by mass.

In addition to the main component, an anionic water-dispersible polyurethane resin, the water-based coating material can contain the above-described components. Furthermore, an additive such as an antifoaming agent or a surfactant may be added in order to improve the coating property when the aqueous coating material is applied to the film. Furthermore, various additives such as an antistatic agent and a slip agent can be added to the water-based coating material as necessary, as long as the adhesiveness is not affected.

By adding a surfactant, wetting of the aqueous coating material on the base film can be particularly promoted. The surfactant is not particularly limited, but anionic surfactants such as polyethylene alkylphenyl ether, polyoxyethylene-fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, alkyl sulfosuccinate, etc. In addition to the agent, nonionic surfactants such as acetylene glycol can be mentioned. The surfactant is preferably contained in the aqueous coating agent in an amount of 0.01 to 1% by mass. Moreover, it is preferable that it volatilizes by the heat processing in the manufacturing process of a polyamide-type film.

As the solvent used in the aqueous coating material, various organic solvents can be used as appropriate in addition to water. Accordingly, for example, an aqueous dispersion in which the resin is dispersed in a solvent (water or the like), a solution in which the resin is dissolved in a solvent (for example, an aqueous solution), or the like can be preferably used.

Easy-slip coat layer In the film of the present invention, an easy-slip coat layer can be formed on the surface where the metal foil is not laminated, if necessary. Thereby, especially the slipperiness (dynamic friction coefficient) of the film of the present invention can be further improved. That is, a slippery coat layer is formed on the surface on which the metal foil is not laminated, and the slippery coat layer is disposed as the outermost layer, thereby providing high slipperiness equivalent to that of the polyamide film of the present invention. A coated film can be provided.

The thickness of the slippery coat layer is not limited, but is usually preferably 0.01 to 0.10 μm, more preferably 0.02 to 0.09 μm. When the thickness of the slippery coat layer is less than 0.01 μm, it becomes difficult to form a layer having a uniform thickness on the film. As a result, the friction coefficient of the polyamide-based film of the present invention is increased and the slipperiness is inferior. On the other hand, when the thickness of the coat layer exceeds 0.10 μm, the effect of improving the slipping property at the time of molding is saturated, which is disadvantageous in terms of cost.

Even when the film of the present invention has a slippery coat layer, the coefficient of dynamic friction on the surface of the slippery coat layer is preferably 0.60 or less, as in the case of the film of the present invention.

As the slippery coat layer, for example, a layer containing various synthetic resins such as polyurethane resin and acrylic resin can be adopted. In particular, a coating layer containing a polyurethane resin having a glass transition temperature of 20 ° C. or higher is preferable. As such a polyurethane resin, for example, an anionic water-dispersible polyurethane resin is preferably contained. The slippery coat layer containing this resin can be suitably formed, for example, by applying an aqueous coating material containing the resin to the surface of the polyamide film.

Commercial products can also be used as such anionic water-dispersible polyurethane resins. For example, “AP-40F” manufactured by DIC, “Superflex 150HS” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Takelac WS-4022”, “Takelac WS-5030”, “Takelac WS-6010”, etc. Can be mentioned.

In the polyamide-based film of the present invention, it is preferable to contain a curing agent such as melamine resin or carbodiimide in the coating layer for the purpose of improving the water resistance and heat resistance of the slippery coating layer. The content of the curing agent is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the anionic water-dispersible polyurethane resin. As these melamine resin, carbodiimide compound and the like, it is preferable to use the same materials as those described in the easy-adhesion coat layer.

In the present invention, for example, a slippery coat layer can be suitably formed by applying an aqueous coating material containing an anionic water-dispersible polyurethane resin. The solid content concentration of the anionic water-dispersible polyurethane resin in the aqueous coating is preferably in the range of 3 to 30% by mass, as in the easy-adhesion coat layer.

In the slippery coat layer, in order to improve the slipperiness of the slippery coat layer, at least one of an inorganic lubricant and an organic lubricant may be included as necessary. As an inorganic lubricant and / or an organic lubricant, the thing similar to what is contained in the above-mentioned polyamide-type film of this invention can be used. The inorganic lubricant or organic lubricant is preferably contained in an amount of about 0.1 to 30.0% by mass in the slippery coat layer.

Further, when an inorganic lubricant and / or an organic lubricant is contained in the easy-sliding coat layer, it is preferable to add these lubricants to the aqueous coating material. In the aqueous coating material, an additive such as an antifoaming agent or a surfactant may be added in order to improve the coating property when applied to the film.

By adding a surfactant, wetting of the aqueous coating material on the base film can be particularly promoted. The surfactant is not particularly limited, and specifically, the same surfactants as those described in the easy adhesion coat layer can be used. Moreover, it is preferable to use the same amount as that of the easy adhesion coat layer.

2. Production method of the present invention The production method of the present invention is a method of producing a biaxially oriented polyamide film,
(1) A sheet forming step of obtaining an unstretched sheet by forming a melt-kneaded material containing a polyamide resin and at least one of an organic lubricant and an inorganic lubricant into a sheet shape,
(2) a stretching step of obtaining a stretched film by biaxially stretching the unstretched sheet sequentially or simultaneously in MD and TD, and
(3) the following formulas a) and b);
a) 0.85 ≦ X / Y ≦ 0.95
b) 8.5 ≦ X × Y ≦ 9.5
(However, X represents the draw ratio of MD and Y represents the draw ratio of TD.)
It is characterized by that.

The sheet forming process sheet forming step, obtaining a polyamide resin, an unstretched sheet by molding the melt-kneaded product containing at least one organic lubricant and inorganic lubricant to the sheet.

As the polyamide resin, the organic lubricant, and the inorganic lubricant, various materials as described above can be used. Various additives can also be contained in the melt-kneaded product. In the production method of the present invention, it is particularly desirable to include both organic lubricants and inorganic lubricants from the viewpoint that the dynamic friction coefficient and the like can be effectively controlled.

The preparation of the melt-kneaded product itself may be performed according to a known method. For example, a raw material containing at least one of a polyamide resin, an organic lubricant, and an inorganic lubricant is put into an extruder equipped with a heating device, melted by heating to a predetermined temperature, and then the molten kneaded product is extruded by a T die. Then, an unstretched sheet which is a sheet-like molded body can be obtained by cooling and solidifying with a casting drum or the like.

The order of addition of polyamide resin, organic lubricant, inorganic lubricant, etc. is not particularly limited. The average thickness of the unstretched sheet is not particularly limited, but is generally about 15 to 250 μm, and preferably 50 to 235 μm. By setting within such a range, the stretching step can be carried out more efficiently.

Stretching process In the stretching process, a stretched film is obtained by biaxially stretching the unstretched sheet sequentially or simultaneously in MD and TD.

As described above, it is preferable that at least one direction of MD and TD is obtained by sequential biaxial stretching including a step of stretching by a tenter. Thereby, a more uniform film thickness can be obtained.

The tenter itself is a device conventionally used for stretching a film, and is a device that widens in the longitudinal direction and / or the lateral direction while gripping both ends of an unstretched sheet. Even when a tenter is used, there are two methods of simultaneous biaxial stretching and sequential biaxial stretching. Simultaneous biaxial stretching using a tenter is a method in which MD and TD are biaxially stretched simultaneously by a tenter by stretching to MD while holding both ends of an unstretched film. On the other hand, sequential biaxial stretching using a tenter is: 1) a method of stretching an MD by passing an unstretched sheet through a plurality of rolls having different rotational speeds, and then stretching the stretched film to TD by a tenter; ) There is a method of stretching an MD of an unstretched sheet with a tenter, and then stretching the stretched film to TD with a tenter. The method of 1) above is particularly preferable in terms of physical properties and productivity of the resulting film. preferable. Regarding the method 1), the unstretched film is sequentially biaxially stretched by the steps as shown in FIG.

First, as shown in FIG. 2, the unstretched sheet 13 is stretched in the MD (longitudinal direction) by passing through a plurality of rolls 21. Since these plural rolls have different rotational speeds, the unstretched sheet 13 is stretched in the MD due to the speed difference. That is, the unstretched sheet is stretched by passing it from the low-speed roll group to the high-speed roll group.

In addition, in FIG. 2, the number of rolls is five, but actually, other numbers may be used. In addition, as the roll, for example, rolls having different functions can be installed in the form of a preheating roll, a stretching roll, and a cooling roll in order. The number of rolls having these functions can also be set as appropriate. Further, when a plurality of stretching rolls are provided, it may be set so that the stretching can be performed in multiple stages. For example, it is possible to appropriately set the MD draw ratio within the range of (E1 × E2) by two-stage drawing in which the first stage is the draw ratio E1 and the second stage is the draw ratio E2. In this way, the first stretched film 13 'is obtained.

Next, the first stretched film 13 ′ that has passed the roll 21 is stretched to TD by being introduced into the tenter 22. More specifically, as shown in FIG. 3, the first stretched film 13 ′ introduced into the tenter 22 is held by a clip connected to a link device 34 that is fixed to the guide rail at both ends near the entrance. It passes through the preheating zone 31, the stretching zone 32, and the relaxation heat treatment zone 33 in the order of the flow direction. The first stretched film 13 ′ is heated to a certain temperature in the preheating zone 31 and then stretched to TD in the stretching zone 32. Thereafter, relaxation treatment is performed at a constant temperature in the relaxation heat treatment zone 33. In this way, the second stretched film 14 (present film) is obtained. Thereafter, the link device 34 fixed to the guide rail is removed from the second stretched film 14 near the exit of the tenter 22 and returned to the vicinity of the entrance of the tenter 22.

Thus, sequential biaxial stretching using a tenter is advantageous in terms of productivity, equipment and the like since MD is stretched by a roll, and is advantageous in controlling film thickness and the like because TD is stretched by a tenter.

In the production method of the present invention, in the stretching step, the following formulas a) and b);
a) 0.85 ≦ X / Y ≦ 0.95
(Preferably 0.89 ≦ X / Y ≦ 0.93)
b) 8.5 ≦ X × Y ≦ 9.5
(Preferably 8.7 ≦ X × Y ≦ 9.1)
(However, X represents the MD draw ratio and Y represents the TD draw ratio).

If any one of the above conditions a) and b) is not satisfied, the resulting polyamide film has a poor balance of stress in the four directions, making it difficult to obtain the film of the present invention.

As the temperature condition in the stretching step, for example, when performing the above-mentioned simultaneous biaxial stretching, it is preferable to stretch in a temperature range of 180 ° C. to 220 ° C. Further, for example, when performing the above-mentioned sequential biaxial stretching, MD stretching may be performed in a temperature range of 50 to 120 ° C. (especially 50 to 80 ° C., more preferably 50 to 70 ° C., and further 50 to 65 ° C.). Preferably, the TD stretching is preferably performed in a temperature range of 70 to 150 ° C. (especially 70 to 130 ° C., more preferably 70 to 120 ° C., and further 70 to 110 ° C.). By controlling in such a temperature range, the film of the present invention can be produced more reliably. These temperatures can be set and controlled while preheating, for example, in the roll 21 (preheating roll) shown in FIG. 2, the preheating zone 31 of the tenter shown in FIG.

Moreover, it is preferable to perform relaxation heat treatment after stretching for both simultaneous biaxial stretching and sequential biaxial stretching using a tenter. The relaxation heat treatment is preferably performed at a relaxation rate of 2 to 5% in the temperature range of 180 to 230 ° C. These temperatures can be set and controlled in the relaxation heat treatment zone 33 of the tenter shown in FIG.

Examples of means for setting the temperature range during stretching as described above include 1) a method of blowing hot air on the film surface, 2) a method of using a far infrared or near infrared heater, and 3) a method of combining them. However, the heating method of the present invention preferably includes a method of blowing hot air.

<Embodiment in stretching process>
As the stretching step in the present invention, a sequential biaxial stretching step in which MD is stretched by a roll and TD is stretched by a tenter can be suitably employed. By adopting this method and satisfying the temperature conditions shown below, it becomes possible to make the thickness balance excellent and the stress balance at the time of stretching in the four directions to be more excellent. The film of the present invention having an average thickness of 16 μm or less can be obtained more reliably and efficiently.

MD stretching First, the temperature in the stretching in the MD, it is preferable to stretch at a temperature range of 50 ~ 70 ° C. using a roll, and more preferably in the Among these 50 ~ 65 ° C..

MD stretching is preferably performed in two or more stages. In this case, it is preferable to increase the draw ratio stepwise. That is, it is preferable to control the draw ratio of the (n + 1) stage to be higher than the draw bridge ratio of the n stage. Thereby, the whole can be stretched more uniformly. For example, when stretching in two stages, the first stage draw ratio is 1.1 to 1.2, and the second stage stretch ratio is 2.3 to 2.6. It can be appropriately set within the range of .53 to 3.12.

Furthermore, it is preferable to provide a temperature gradient in MD stretching. In particular, it is preferable to increase the temperature sequentially along the film take-off direction, and the temperature gradient (the temperature T1 at the beginning (inlet) and the end (outlet) in the running direction of the film) in the entire stretched portion of the MD. The temperature difference from T2 is usually preferably 2 ° C. or higher, and more preferably 3 ° C. or higher. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film is preferably usually 1 to 5 seconds, more preferably 2 to 4 seconds. preferable.

TD Stretching TD stretching is performed by a tenter in which each zone is formed as shown in FIG. At this time, the temperature of the preheating zone 31 is preferably 60 to 70 ° C. The temperature of the stretching zone 32 is preferably in the temperature range of 70 to 130 ° C., more preferably in the temperature range of 75 to 120 ° C., and most preferably in the temperature range of 80 to 110 ° C. preferable.

In the stretching zone 32 as well, it is preferable to gradually increase the temperature along the film take-off direction. In the entire stretching zone, the temperature gradient (the temperature T1 at the beginning (inlet) of the film running direction ends (outlet). The temperature difference between the temperature T2 and the temperature T2) is usually preferably 5 ° C. or higher, more preferably 8 ° C. or higher. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film in the stretching zone 32 is preferably 1 to 5 seconds, particularly 2 to 4 seconds. It is more preferable.

In the relaxation heat treatment zone 33, it is desirable to perform relaxation heat treatment. The heat treatment temperature is preferably in the range of 180 to 230 ° C., more preferably in the range of 180 to 220 ° C., and most preferably in the range of 180 to 210 ° C. The relaxation rate is usually preferably about 2 to 5%.

Further, when obtaining a coated film having a coating layer (especially at least one of an easy-adhesion coating layer and a slippery coating layer) on at least one surface of the polyamide-based film surface of the present invention, the same stretching method and stretching as described above. It is preferable to carry out under conditions.

In particular, in order to form a coat layer on the surface of the polyamide-based film, it is preferable to apply an aqueous coating to the polyamide-based film after being stretched to MD in the production method as described above. Then, it is preferable to stretch the film to TD under the same stretching conditions as described above together with the aqueous coating material (coating film) (in-line coating). The coating amount of the aqueous coating agent is preferably adjusted so that the thickness of the coating layer formed on the stretched film surface is 0.01 to 0.10 μm.

In the production method of the present invention, it is desirable that a stretching method other than the above is not adopted as the stretching step from the viewpoint of maintaining the uniformity of thickness. For example, it is desirable not to include a stretching step by a tubular method (inflation method).

Hereinafter, examples and comparative examples will be shown to describe the features of the present invention more specifically. However, the scope of the present invention is not limited to the examples.

Example 1
(1) Manufacture of a polyamide-type film First, the component shown in Table 1 was used as a raw material, respectively.

Using the above raw materials, polyamide resin (polyamide 6 resin) / silica-containing polyamide resin / organic lubricant-containing polyamide resin = 91.5 parts by mass / 2.5 parts by mass / 6.0 parts by mass in the extruder An unstretched sheet was produced by melt-kneading, supplying to a T-die, discharging it into a sheet, winding it around a metal drum whose temperature was adjusted to 20 ° C., cooling and winding it. At this time, the supply amount of the polyamide resin and the like were adjusted so that the thickness of the polyamide-based film obtained after stretching was 12 μm.

Then, the obtained unstretched sheet was subjected to a stretching process by sequential biaxial stretching. More specifically, using an apparatus as shown in FIG. 2, MD was stretched using a roll, and TD was stretched using a tenter.

First, the MD was stretched by passing the sheet through a plurality of rolls so that the total stretching ratio was 2.85 times. At this time, stretching is performed in two stages, the stretching ratio of the first stage is 1.1, the stretching ratio of the second stage is 2.59, and the total stretching ratio (MD1 × MD2) 1.1 × 2.59 = 2.85 times. The heating conditions were stretched along the film take-off direction by providing a temperature gradient such that the beginning (T1) of the running direction was 54 ° C. and the end (T2) was 57 ° C. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film was about 3 seconds.

Next, TD stretching was performed using a tenter as shown in FIG. First, the preheating zone 31 (preheating part) was stretched 3.2 times to TD in the stretching zone 32 while preheating at 65 ° C. At this time, a temperature gradient was provided in the stretching zone 32 (stretching portion) so that the beginning (T1) of the running direction was 74 ° C. and the end (T2) was 96 ° C. along the film take-up direction. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film in the stretching zone was about 3 seconds.

The film that passed through the stretching zone was subjected to relaxation heat treatment in the relaxation heat treatment zone 33 (heat treatment section) at a temperature of 202 ° C. and a relaxation rate of 3%. In this way, a biaxially stretched polyamide film (rolling amount 2000 m) was obtained by continuously producing 1000 m or more. The obtained film was wound up into a roll.

(2) Production of Laminate A coating amount of a two-component polyurethane adhesive (“TM-K55 / CAT-10L” manufactured by Toyo Morton Co., Ltd.) is applied to the biaxially stretched polyamide film obtained in (1) above. After applying to 5 g / m ² , it was dried at 80 ° C. for 10 seconds. A metal foil (a 50 μm thick aluminum foil) was bonded to the adhesive application surface. Next, after applying the adhesive on the aluminum foil side of the laminate of polyamide film and aluminum foil under the same conditions, a sealant film (unstretched polypropylene film (GHC thickness 50 μm, manufactured by Mitsui Chemicals, Inc.) was applied to the coated surface. )) And pasted for 72 hours in an atmosphere of 40 ° C. to produce a laminate (polyamide film / aluminum foil / sealant film).

Examples 2 to 40, Comparative Examples 1 to 20
The raw material composition was changed so that the production conditions and the target thickness of the stretched polyamide film were changed to those shown in Tables 2 to 4, and the organic lubricant or inorganic lubricant content was as shown in Tables 8 to 10. A polyamide film was obtained in the same manner as in Example 1 except that the ratio was changed. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 1. However, Example 7, Example 17, and Example 38 were more specifically changed as follows.

(1) About Example 7
In the laminate obtained in Example 1, a coating amount of a two-component polyurethane adhesive (TM-K55 / CAT-10L manufactured by Toyo Morton Co., Ltd.) is applied to the surface of the polyamide film on which the aluminum foil is not laminated. After applying to 5 g / m ² , it was dried at 80 ° C. for 10 seconds. A PET film (“Emblet PET-12”, thickness 12 μm, manufactured by Unitika) was bonded to the adhesive-coated surface to prepare a laminate (PET film / polyamide film / aluminum foil / sealant film).

(2) About Example 17
Using the raw materials shown in Table 1, polyamide resin (polyamide 6 resin) / polyamide resin (polyamide 66 resin) / silica-containing polyamide resin / organic lubricant-containing polyamide resin = 81.8 / 9.7 / 2.5 / 6. A polyamide-based film was obtained in the same manner as in Example 1 except that the composition ratio was changed to 0 part by mass and the production conditions were changed to those shown in Table 2. A laminate was produced in the same manner as in Example 1 using the obtained polyamide film.

(3) About Example 38
What added 1 mass% of organic lubricant "ethylenebisbehenamide (commercially available)" to nylon 6 resin (product name "A1030BRF" manufactured by Unitika Ltd.) as the organic lubricant-containing polyamide resin of Table 1 Other than using, the raw materials shown in Table 1 were used, and polyamide resin (polyamide 6 resin) / polyamide resin (polyamide 66 resin) / silica-containing polyamide resin / organic lubricant-containing polyamide resin = 81.8 / 9.7 / 2 A polyamide-based film was obtained in the same manner as in Example 1 except that the composition ratio was changed to 5 / 6.0 parts by mass and the production conditions were changed to those shown in Table 3. A laminate was produced in the same manner as in Example 1 using the obtained polyamide film.

Test example 1
The physical properties of the polyamide films and laminates obtained in Examples 1 to 40 and Comparative Examples 1 to 20 were evaluated. The evaluation results are shown in Tables 5 to 10. In addition, the measurement method and evaluation method of various physical properties were performed as follows.

(1) Stresses in 4 directions when 5% and 15% stretches of polyamide-based film The stresses in 4 directions when 5% and 15% stretches of polyamide-based films are MD in the reference direction (0 degree direction). Then, it was measured and calculated by the method described above.
In addition, as a sample film used for the measurement, in the polyamide-based film wound around the obtained film roll, a sample collected at a position near the center of the winding width and half of the winding amount was used. .

(2) Average thickness and standard deviation of polyamide film The average thickness and standard deviation of the polyamide film were measured and calculated by the methods described above. In addition, the sample film used for the measurement was the following three types.
In the polyamide-based film wound up on the obtained film roll, a) a sample collected at a position near the center of the winding width and half the winding amount is denoted as “A”, and b) the winding width. Sampled at a position near the right end of the winding and at half the winding amount is denoted as “B”, and c) Sampled at a position near the left end of the winding width and near the end of the winding Indicated as “C”.

(3) Dynamic friction coefficient, haze, arithmetic average height Sa of polyamide film
The dynamic friction coefficient, haze, and arithmetic average height Sa of the polyamide film were measured by the method described above. In addition, as a sample film used for the measurement, in the polyamide-based film wound around the obtained film roll, a sample collected at a position near the center of the winding width and half of the winding amount was used. .
In addition, about the coat film, the surface where slipperiness was requested | required in cold forming was made into the measuring object. That is, with respect to a coat film in which an easy-adhesion coat layer is formed on a polyamide film, the surface on which the coat layer is not formed was used as a measurement target. Moreover, about the coat film which formed the slippery coat layer in the polyamide-type film, the surface of the said coat layer was made into the measuring object.

(4) Thickness of coat layer (easy-adhesive coat layer or slippery coat layer) A coat film in which a coat layer is formed on a polyamide-based film is embedded in an epoxy resin, and a slice with a thickness of 100 nm is formed with a frozen ultramicrotome. Collected. The cutting temperature was −120 ° C., and the cutting speed was 0.4 mm / min. The collected sections were subjected to gas phase staining with a RuO ₄ solution for 1 hour, and the thickness of the coating layer was measured by transmission measurement at an acceleration voltage of 100 kV using JEM-1230 TEM (manufactured by JEOL Ltd.). At this time, arbitrary 5 points | pieces were selected for the location which measures the thickness of a coating layer, and the average value of the measured value of 5 points | pieces was made into thickness.
In addition, as the sample film used for the measurement, the sample film collected at a position near the center of the winding width and half the winding amount in the coated film wound up on the obtained film roll was used.

(5) Moldability and heat-and-moisture resistance of laminates 1) Moldability (drawing depth; Eriksen test)
Based on JISZ2247, an Erichsen test machine (No. 5755 manufactured by Yasuda Seiki Seisakusho Co., Ltd.) was used, and a steel ball punch was pressed to the obtained laminate with a predetermined indentation depth to obtain an Erichsen value. The Eriksen value was measured every 0.5 mm. The case where the Erichsen value was 5 mm or more was suitable, and the case where the Eriksen value was 8 mm or more was determined to be suitable by deep drawing. The pushing speed of the steel ball punch was 0.20 mm / s, and the measurement environment was 23 ° C. × 90% RH.
2) Moist heat resistance
In order to evaluate the molding stability under high-temperature and high-humidity conditions, the obtained laminate was used at 120 ° C. for 30 minutes, 1.8 kg / 1.8 ° C. using a high-temperature and high-pressure cooking sterilizer RCS-60SPXTG. After the treatment with cm ² , the same Erichsen test as in 1) was performed. At this time, the case where the Eriksen value is 7 mm or more is “◎”, the case where the Eriksen value is 6 mm or more and less than 7 mm is “◯”, the case where the Eriksen value is 5 mm or more and less than 6 mm is “△”, the Eriksen value The case where is less than 5 mm is indicated as “x”.

As is clear from these results, in Examples 1 to 40, since the draw ratio of the polyamide film was in a predetermined range, the obtained polyamide film was in the 0 degree direction (MD) in the uniaxial tensile test. The difference between the maximum and minimum values of stress at 5% elongation in the 45 °, 90 ° (TD) and 135 ° directions is 35 MPa or less, and the maximum and minimum values of stress at 15% elongation The difference between the two satisfied 40 MPa or less. And the laminated body obtained using these polyamide-type films had a high Erichsen value, and had the uniform extensibility to all directions when cold-molding. That is, it can be seen that the polyamide film of each example can exhibit excellent moldability without causing breakage, delamination, pinholes, or the like of the aluminum foil.

Moreover, since the polyamide-based films obtained in Examples 1 to 40 manufactured as described above are also controlled to have a dynamic friction coefficient of 0.60 or less, they are particularly excellent in slipperiness under high humidity conditions. It can be seen that it is excellent in cold formability.

On the other hand, in Comparative Examples 1 to 16, since the draw ratio of the polyamide-based film did not satisfy the predetermined range, the obtained polyamide-based film was measured in the 0 degree direction (MD) and 45 degree direction in the uniaxial tensile test. The difference between the maximum value and the minimum value of the stress at 5% elongation in the 90 degree (TD) direction and the 135 degree direction is 35 MPa or less, and the difference between the maximum value and the minimum value of the stress at 15% elongation is 40 MPa. The following were not met. For this reason, the laminates obtained using the polyamide-based films of these comparative examples have low Erichsen values, and cannot be uniformly stretched in all directions when cold-molded. It was confirmed that it was inferior. In Comparative Examples 17 to 20, the obtained polyamide film also had a high dynamic friction coefficient, so the friction between the polyamide film and the molding die was large, the slipperiness was poor, the Erichsen value was low, and the moldability was poor. You can see that

Example 41
(1) Production of a coat film having an easy-adhesion coat layer (primer layer)
First, the components shown in Table 1 were used as raw materials. Using the above raw materials, polyamide resin (polyamide 6 resin) / silica-containing polyamide resin / organic lubricant-containing polyamide resin = 91.5 parts by mass / 2.5 parts by mass / 6.0 parts by mass in the extruder An unstretched sheet was produced by melt-kneading, supplying to a T-die, discharging it into a sheet, winding it around a metal drum whose temperature was adjusted to 20 ° C., cooling and winding it. At this time, the supply amount of the polyamide resin and the like were adjusted so that the thickness of the polyamide-based film obtained after stretching was 15 μm.

Then, the obtained unstretched sheet was subjected to a stretching process by sequential biaxial stretching. More specifically, using the apparatus as shown in FIG. 2, the MD of the sheet was stretched using a roll, and then TD was stretched using a tenter.

First, the MD was stretched by passing the sheet through a plurality of stretching rolls so that the total stretching ratio was 2.85 times. At this time, stretching is performed in two stages, the stretching ratio of the first stage is 1.1, the stretching ratio of the second stage is 2.59, and the total stretching ratio (MD1 × MD2) 1.1 × 2.59 = 2.85 times. The heating conditions were stretched along a film take-off direction by providing a temperature gradient such that the beginning (T1) of the running direction was 58 ° C. and the end (T2) was 61 ° C. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film was about 3 seconds.

After stretching the MD, in order to form an easy-adhesion coat layer, a polyurethane water dispersion was coated on one side with a gravure coater so that the coat thickness after stretching was 0.03 to 0.08 μm. Thereafter, TD was stretched. As the aqueous dispersion, 7 parts by mass of tri (methoxymethyl) melamine resin (“Beccamin APM” manufactured by DIC) is used with respect to 100 parts by mass of an anionic water-dispersible polyurethane resin (“Hydran KU400SF” manufactured by DIC). An aqueous coating obtained by mixing was used.

Next, TD stretching was performed using a tenter as shown in FIG. First, the preheating zone 31 (preheating part) was stretched 3.2 times to TD in the stretching zone 32 while preheating at 70 ° C. At this time, in the stretching zone 32 (stretching portion), a temperature gradient was provided along the film take-up direction so that the beginning (T1) of the running direction was 78 ° C. and the end (T2) was 100 ° C. At this time, the running time (heating time) of the film from the beginning (inlet) to the end (outlet) of the running direction of the film in the stretching zone was about 3 seconds.

The film that passed through the stretching zone was subjected to relaxation heat treatment in the relaxation heat treatment zone 33 (heat treatment section) at a temperature of 202 ° C. and a relaxation rate of 3%. In this way, by continuously producing 1000 m or more, a coated film (winding amount 2000 m) in which an easy-adhesion coating layer was formed on one side of a biaxially stretched polyamide film was obtained. The obtained film was wound up into a roll.

(2) Production of Laminate As in Example 1 except that the coat film obtained in (1) above was used and an aluminum foil was laminated on the surface of the easy-adhesion coat layer using a two-component polyurethane adhesive. Thus, a laminate (coat film / aluminum foil / sealant film) was produced.

Examples 42 to 84, Comparative Examples 21 to 44
The production conditions and the target thickness of the polyamide-based film after stretching were changed to those shown in Tables 11 to 14, and the composition ratios of the raw materials were adjusted so that the organic lubricant or inorganic lubricant content was as shown in Tables 21 to 24. A coated film was obtained in the same manner as in Example 41, except that was changed. Using the obtained coated film, a laminate was produced in the same manner as in Example 41. However, Example 47, Example 55, Example 63, Example 83, and Example 84 were more specifically changed as follows.

(1) About Example 47 In the laminate obtained in Example 41, a two-component polyurethane adhesive (TM-K55 / CAT- manufactured by Toyo Morton Co., Ltd.) was applied to the surface of the coat film on which the aluminum foil was not laminated. 10 L) was applied so that the application amount was 5 g / m ² and then dried at 80 ° C. for 10 seconds. A PET film (Embret PET-12 thickness 12 μm manufactured by Unitika) was bonded to the adhesive-coated surface to prepare a laminate (PET film / coat film / aluminum foil / sealant film).

(2) About Example 55 In the laminate obtained in Example 48, a two-component polyurethane adhesive (TM-K55 / CAT- manufactured by Toyo Morton Co., Ltd.) was applied to the surface of the coat film on which the aluminum foil was not laminated. 10 L) was applied so that the application amount was 5 g / m ² and then dried at 80 ° C. for 10 seconds. A PET film (Embret PET-12 manufactured by Unitika Ltd., thickness 12 μm) was bonded to the adhesive-coated surface to prepare a laminate (PET film / coat film / aluminum foil / sealant film).

(3) About Example 63 Using the raw materials shown in Table 1, polyamide resin (polyamide 6 resin) / polyamide resin (polyamide 66 resin) / silica-containing polyamide resin / organic lubricant-containing polyamide resin = 81.8 / 9.7 A coated film was obtained in the same manner as in Example 48 except that the composition ratio was changed to 2.5 / 6.0 parts by mass and the production conditions were changed to those shown in Table 12. Using the obtained coated film, a laminate was produced in the same manner as in Example 41.

(4) About Example 83 The same method as in Example 41 except that an anionic water-dispersible polyurethane resin (“Hydran AP201” manufactured by DIC) was used as the polyurethane water dispersion for forming the easy-adhesion coat layer. A coated film was obtained. Using the obtained coated film, a laminate was produced in the same manner as in Example 41.

(5) About Example 84
An anionic water-dispersible polyurethane resin (“Hydran AP201” manufactured by DIC) is used as a polyurethane water dispersion for forming an easy-adhesion coat layer, and a carbodiimide-based curing agent (“Carbodilite V-02” manufactured by Nisshinbo Chemical Co., Ltd.) is used as a curing agent. A coated film was obtained in the same manner as in Example 49 except that -L2 ") was used. Using the obtained coated film, a laminate was produced in the same manner as in Example 41.

Example 85
(1) Manufacture of a coat film having a slippery coat layer
MD was extended | stretched about the unstretched sheet obtained by the same method using the raw material similar to Example 41. FIG. After stretching the MD, in order to form a slippery coat layer, a polyurethane water dispersion was coated on one side with a gravure coater so that the coat thickness after stretching was 0.05 μm. Thereafter, TD was stretched. As the water dispersion, an aqueous coating material obtained from an anionic water-dispersible polyurethane resin (Mitsui Chemicals Polyurethane “Takelac WS-4022”) was used.

Next, the TD stretching and the subsequent steps were performed in the same manner as in Example 41 to obtain a coated film.

(2) Production of Laminate A two-component polyurethane adhesive (“TM-” manufactured by Toyo Morton Co., Ltd.) is applied to the surface of the obtained coated film where the slippery coating layer is not formed (that is, the polyamide film surface). K55 / CAT-10L ") was applied so that the coating amount was 5 g / m ² and then dried at 80 ° C for 10 seconds. A metal foil (a 50 μm thick aluminum foil) was bonded to the adhesive application surface. Next, after apply | coating the said adhesive agent on the said aluminum foil surface on the same conditions, the sealant film (Unstretched polypropylene film (GHC thickness 50micrometer made by Mitsui Chemicals Tosero Co., Ltd.)) is bonded on the application surface, Aging treatment was performed for 72 hours in an atmosphere to prepare a laminate (coat film / aluminum foil / sealant film).

Examples 86-89
The same method as in Example 85, except that the manufacturing conditions and the target thickness of the polyamide-based film after stretching were changed to those shown in Table 15 and the thickness of the slippery coating layer was changed to that shown in Table 20. A coated film was obtained. Using the obtained coated film, a laminate was produced in the same manner as Example 85.

Example 90
MD was extended | stretched about the unstretched sheet obtained by the same method using the raw material similar to Example 41. FIG. After stretching the MD, in order to form a slippery coat layer, a polyurethane water dispersion was coated on one side with a gravure coater so that the coat thickness after stretching was 0.05 μm. Thereafter, TD was stretched. As the aqueous dispersion, an aqueous coating material obtained by mixing silica as an inorganic lubricant with an anionic water-dispersible polyurethane resin (Mitsui Chemicals Polyurethane “Takelac WS-4022”) was used. Next, after extending | stretching TD, it carried out by the method similar to Example 41, and obtained the coat film. The obtained coated film contained 0.6% by mass of silica in the slippery coating layer. Using the obtained coated film, a laminate was produced in the same manner as Example 85.

Examples 91-94
The same method as in Example 90 except that the manufacturing conditions and the target thickness of the polyamide-based film after stretching were changed to those shown in Table 15 and the thickness of the slippery coating layer was changed to that shown in Table 20. A coated film was obtained. Using the obtained coated film, a laminate was produced in the same manner as in Example 90.

Test example 2
The physical properties of the coated films and laminates obtained in Examples 41 to 94 and Comparative Examples 21 to 44 were evaluated. The evaluation results are shown in Tables 16 to 25. Various physical properties were measured and evaluated in the same manner as in Test Example 1.

As is apparent from these results, in Examples 41 to 94, since the draw ratio of the polyamide film was in a predetermined range, the obtained coated film was in the 0 degree direction and 45 degree direction in the uniaxial tensile test. The difference between the maximum value and minimum value of stress at 5% elongation in the 90 ° direction and 135 ° direction is 35 MPa or less, and the difference between the maximum value and minimum value of stress at 15% elongation satisfies 40 MPa or less. It became a thing. And the laminated body obtained using these coat films had a high Erichsen value, and had uniform extensibility in all directions when cold-molded. In other words, it can be seen that the coated films of these examples have excellent moldability without causing the aluminum foil to break, delamination, pinholes, or the like. In addition, the coated films obtained in Examples 41 to 94 are also excellent in slipperiness and cold formability under high humidity because the dynamic friction coefficient is controlled to 0.60 or less. I understand that.

In addition, since the coated films obtained in Examples 41 to 84 have an easy-adhesive coating layer containing an anionic water-dispersible polyurethane resin on one side, laminates using these coated films are resistant to moisture. It can be confirmed that the heat is also excellent.

Furthermore, since the coated films obtained in Examples 85 to 94 have a slippery coat layer on one side, the coefficient of dynamic friction is low, and the laminate using the coat film is excellent in slipperiness. It can be seen that it is particularly excellent in cold formability under high humidity.

On the other hand, in Comparative Examples 21 to 40, since the draw ratio of the polyamide film did not particularly satisfy the predetermined range, the obtained coated film was subjected to the 0 degree direction, 45 degree direction, 90 degree in the uniaxial tensile test. The difference between the maximum and minimum values of stress at 5% elongation in the direction of 135 ° and 135 ° is 35 MPa or less, and the difference between the maximum and minimum values of stress at 15% elongation does not satisfy 40 MPa or less. It became. For this reason, the laminates obtained using the coating films of these comparative examples have a low Erichsen value and cannot be uniformly stretched in all directions when cold-molded. You can see that it is inferior. In Comparative Examples 41 to 44, since the obtained coated film had a high dynamic friction coefficient, the friction between the coated film and the mold for molding was large, the slipperiness was poor, the Erichsen value was low, and the moldability was poor. It turns out that it is a thing.

Claims (12)

1. A polyamide film having the following characteristics (1) to (3):
   (1) Each stress at 5% elongation by a uniaxial tensile test in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction from an arbitrary point on the film. The difference between the maximum and minimum values is 35 MPa or less,
   (2) In the above four directions, the difference between the maximum value and the minimum value of each stress at 15% elongation by uniaxial tensile test is 40 MPa or less, and (3) the dynamic friction coefficient is 0.60 or less. A polyamide-based film characterized by that.
2. 2. The polyamide film according to claim 1, wherein the arithmetic average height Sa is 0.01 to 0.15 μm.
3. With respect to an average thickness in eight directions of 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees in a clockwise direction with respect to a certain direction from an arbitrary point on the film. The polyamide-type film of Claim 1 whose standard deviation is 0.200 micrometer or less.
4. The polyamide film according to claim 1, wherein the average thickness is 16 µm or less.
5. The polyamide film according to claim 1, wherein the polyamide film contains at least one of an organic lubricant and an inorganic lubricant.
6. A coated film comprising the polyamide-based film according to claim 1 and an easy adhesion coating layer and / or a slipping coating layer formed on the film.
7. A laminate comprising the film according to claim 1 or 6 and a metal foil laminated on the film.
8. A container comprising the laminate according to claim 7.
9. A method for producing a polyamide film comprising:
   (1) A sheet forming step of obtaining an unstretched sheet by forming a melt-kneaded material containing a polyamide resin and at least one of an organic lubricant and an inorganic lubricant into a sheet shape,
   (2) including a stretching step of obtaining a stretched film by biaxially stretching the unstretched sheet sequentially or simultaneously in MD and TD, and
   (3) the following formulas a) and b);
   a) 0.85 ≦ X / Y ≦ 0.95
   b) 8.5 ≦ X × Y ≦ 9.5
   (However, X represents the draw ratio of MD and Y represents the draw ratio of TD.)
   A method for producing a polyamide-based film.
10. The stretching process is sequential biaxial stretching,
    (2-1) a first stretching step for obtaining a first stretched film by stretching the unstretched sheet into MD at a temperature of 50 to 120 ° C. and (2-2) the first stretch step at a temperature of 70 to 150 ° C. The manufacturing method of Claim 9 including the 2nd extending process which obtains a 2nd stretched film by extending | stretching 1 stretched film to TD.
11. The manufacturing method according to claim 10, wherein the first stretching step is stretching using a roll, and the second stretching step is stretching using a tenter.
12. The production method according to claim 10, wherein the second stretched film is further subjected to relaxation heat treatment at a temperature of 180 to 230 ° C.

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