JP2021088190A - Polyamide-based film and method for producing the same - Google Patents

Abstract

To provide a polyamide-based film having the excellent uniformity of a thickness and having comparatively less variations in physical properties in four directions including 0-degree direction, 45-degree direction, 90-degree direction, and 135-degree direction; and to provide a method for producing the polyamide-based film.SOLUTION: In the polyamide-based film, (1) a specific direction from an optional point in the film is assumed to be 0 degree, each of elastic moduli measured in four directions including directions clockwise at 45 degrees, 90 degrees, and 135 degrees with respect to the direction is 1.3 to 3.5 GPa, and the difference between the maximum and minimum values of the elastic moduli is 0.5 GPa or less; and (2) the absolute value of the difference between molding work energies measured in the two directions of 0 degree and 90 degrees [(molding work energy in the 0-degree direction)-(molding work energy in the 90-degree direction)] is 0.02 N m or less.SELECTED DRAWING: Figure 5

Description

The present invention relates to a novel polyamide-based film and a method for producing the same. Furthermore, the present invention relates to a laminate and a container containing the polyamide film.

Various resin films are made into various products such as packaging bodies by subjecting them to various processes. For example, a vinyl chloride film is used for a package (press-through pack) of a drug (tablet) or the like. Further, for example, polypropylene film is used when packaging contents that require moisture resistance. In recent years, a laminate made by laminating a metal foil on a resin film has been used for the purpose of imparting more excellent gas barrier property or moisture proof property from the viewpoint of maintaining the quality of the 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, metal can type exterior materials for lithium-ion batteries have been the mainstream, but drawbacks such as low degree of freedom in shape and difficulty in weight reduction have been pointed out. Therefore, 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 laminate has become widely used because it is more flexible than a metal can, has a high degree of freedom in shape, can be made lighter by thinning, and is easily miniaturized. ing.

Various performances are required for the laminate used in the above applications, and in particular, moisture resistance is a very important factor. However, a metal foil such as an aluminum foil that imparts moisture resistance is poor in malleability by itself and is inferior in moldability. Therefore, by using a polyamide-based film as the resin film constituting the base material layer, ductility is imparted and moldability is improved.

The moldability in this case is the moldability especially when the film is cold-molded (cold-processed). That is, when a product is manufactured by molding a film, the molding conditions are a) hot molding in which the resin is melted under heating and b) cold molding in which the resin is molded as a solid without melting. There is inter-molding, but in the above applications, formability 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 there is no heating process, and that the original characteristics of the resin can be brought out. Therefore, as a polyamide-based film, the development of a film suitable for cold molding is underway.

As such a polyamide-based film, a stretch-processed polyamide-based film is known (for example, Patent Documents 1 and 2). However, these polyamide-based films are produced by stretching by a tubular method. That is, not only is the productivity low, but the obtained stretched film 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 the laminate of the film and the metal foil is processed by cold molding, the metal foil may be broken or a fatal defect such as a pinhole may occur.

On the other hand, a polyamide-based film stretched by the tenter method has also been proposed (for example, Patent Documents 3 to 10). The tenter method is more advantageous than the tubular method in terms of productivity, dimensional stability, and the like.

Patent No. 5487485 Patent No. 5226942 Patent No. 5467387 JP 2011-162702 JP 2011-255931 JP 2013-189614 Patent No. 5226941 Japanese Unexamined Patent Publication No. 2013-22773 International release WO2014 / 08424 Patent No. 3671978

However, even in the polyamide-based film stretched by the tenter method, there are still variations (anisotropic) in physical properties in each direction of the film. Therefore, it cannot be said that the moldability at the time of cold molding (particularly deep drawing molding) is sufficiently satisfactory.

The polyamide-based film 14 is manufactured by a process as shown in FIG. First, the melt-kneaded product 12 is prepared by melting the raw material 11 in the melt-kneading step 11a. The melt-kneaded product 12 is molded into a sheet by the molding step 12a to obtain an unstretched sheet 13. Next, the unstretched sheet 13 is biaxially stretched in the stretching step 13a to obtain a polyamide-based film 14. Further, the stretched polyamide film 14 is laminated in a cold molding step 15a as a secondary process after producing a laminated body 17 through a laminating step 14a in which, for example, a metal foil layer 15 and a sealant film 16 are laminated in order. When the body 17 is processed into a predetermined shape, it becomes various products 18 (for example, a container).

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

When the laminate 17 including the stretched polyamide film 14 is subjected to the cold molding step 15a, the polyamide film 14 is stretched in all directions. Therefore, if the physical properties of the polyamide film 14 in the four directions vary. During cold molding, it becomes difficult to stretch the film uniformly in all directions. That is, the presence of a direction in which the metal foil is easily stretched and a direction in which the metal foil is difficult to stretch causes the metal foil to break, and delamination or pinholes occur. When such a problem occurs, the function as a package or the like cannot be fulfilled, which may lead to damage to the packaged body (contents) or the like. Therefore, it is necessary to reduce the variation in physical properties in each direction as much as possible.

In this case, the thickness of the film is one of the physical characteristics that affect the moldability during cold molding. When a laminate containing a polyamide-based film having a variation in film thickness is cold-molded, there is a high possibility that a relatively thin portion will be torn to cause pinholes or delamination. Therefore, it is indispensable to uniformly control the thickness of the polyamide-based film used for cold molding over the entire film.

Here, regarding the uniformity of the thickness of the polyamide film, although it is better when it is stretched by the tenter method than by the tubular method, the thickness accuracy of the polyamide film obtained by the above-mentioned Patent Documents 3 to 10 is improved. Is not fully satisfactory. That is, at the time of cold molding, it is necessary to uniformly stretch in the four directions of vertical, horizontal and diagonal directions as described above, and therefore it is necessary to have a uniformity of sufficient thickness to withstand cold molding. In particular, the thinner the film thickness (particularly, the thickness is 15 μm or less), the more remarkable the influence of the thickness uniformity on the moldability.

In general, the thicker the film, the easier it is to secure the uniformity of the thickness of the film. Therefore, it is conceivable to design the film to be relatively thick in order to secure the uniformity of the thickness. However, in recent years, polyamide-based films used for cold molding and their laminates have been widely used mainly for exterior materials of lithium-ion batteries, and the output and miniaturization of batteries have been further increased. With the demand for cost reduction and the like, it is required to make the thickness of the polyamide film thinner. However, the thinner the thickness, the more difficult it becomes to ensure the uniformity of the thickness.

As described above, even if the film thickness is thinner, the development of a polyamide-based film having excellent thickness uniformity and relatively small variation in physical properties in the above four directions is desired, but such a film has not been developed yet. The current situation is that it has not been done.

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

The present inventor has achieved the above object based on the finding that a polyamide-based film having peculiar physical properties can be obtained by adopting a specific manufacturing method as a result of intensive research in view of the problems of the prior art. We have found and completed the present invention.

That is, the present invention relates to the following polyamide-based film and a method for producing the same.
1. 1. It is a polyamide film,
(1) The elastic modulus measured in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction as 0 degree from an arbitrary point on the film is 1.3 to 3 in each case. It is .5 GPa, and the difference between the maximum value and the minimum value of these elastic moduli is 0.5 GPa or less.
(2) The absolute value of the difference [(molding work energy in the 0 degree direction)-(molding work energy in the 90 degree direction)] measured in the two directions of 0 degree and 90 degree is 0.02N.・ M or less,
A polyamide-based film characterized by this.
2. Item 2. The polyamide-based film according to Item 1, wherein the dynamic friction coefficient is 0.60 or less.
3. 3. Item 2. The polyamide-based film according to Item 1, wherein the arithmetic mean roughness Sa is 0.01 to 0.15 μm.
4. With respect to the average thickness in eight directions of 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees clockwise with respect to a specific direction as 0 degrees from an arbitrary point on the film. Item 2. The polyamide-based film according to Item 1, wherein the standard deviation value is 0.200 or less.
5. Item 2. The polyamide-based film according to Item 1, wherein the average thickness is 16 μm or less.
6. Item 2. The polyamide-based film according to Item 1, which contains at least one of an organic lubricant and an inorganic lubricant.
7. Furthermore, (3) each of the four directions of 45 degrees, 90 degrees and 135 degrees clockwise with respect to the specific direction from an arbitrary point on the film at the time of 5% elongation by the uniaxial tensile test. The difference between the maximum value and the minimum value of the stress is 35 MPa or less, and (4) the difference between the maximum value and the minimum value of each stress at the time of 15% elongation by the uniaxial tensile test in the above four directions is 40 MPa or less. Item 2. The polyamide-based film according to Item 1.
8. Item 2. A laminate containing the polyamide-based film according to Item 1 and a metal foil laminated on the film.
9. A container containing the laminate according to item 8.
10. This is a method for producing a polyamide film.
(1) A sheet molding step of obtaining an unstretched sheet by molding a melt-kneaded product containing a polyamide resin into a sheet.
(2) A stretching step of obtaining a stretched film by sequentially or simultaneously biaxially stretching the unstretched sheet to MD and TD is included, and
(3) The following formulas a) and b);
a) 0.85 ≤ X / Y ≤ 0.95
b) 8.5 ≤ X x Y ≤ 9.5
(However, X indicates the stretching ratio of the MD, and Y indicates the stretching ratio of the TD.)
Meet both
A method for producing a polyamide-based film.
11. The stretching process is sequential biaxial stretching,
(2-1) The first stretching step of obtaining a first stretched film by stretching the unstretched sheet to MD at a temperature of 50 to 120 ° C. and (2-2) the first stretching step at a temperature of 70 to 150 ° C. Item 10. The production method according to Item 10, further comprising a second stretching step of obtaining a second stretched film by stretching one stretched film to TD.
12. Item 2. The production method according to Item 11, wherein the first stretching step is stretching using a roll, and the second stretching step is stretching using a tenter.
13. Item 2. The production method according to Item 11, wherein the second stretched film is further subjected to a relaxation heat treatment at a temperature of 180 to 230 ° C.
14. Item 2. The polyamide-based film according to Item 1, which is used for cold molding.
15. Item 12. The polyamide-based film according to Item 14, wherein the cold molding includes deep drawing.
16. A container obtained by cold-molding the laminate according to Item 8.
17. Item 8. A method for producing a container from the laminate according to Item 8, wherein the method includes a step of cold-molding the laminate.

The polyamide-based film of the present invention is excellent in thickness uniformity, and has physical properties (elastic modulus, etc.) in four directions consisting of 0 degree direction, 45 degree direction, 90 degree direction, and 135 degree direction clockwise with reference to an arbitrary direction. ) Is excellent in balance. Therefore, for example, in a laminate in which the film of the present invention and a metal foil are laminated, the metal foil has good ductility, and when drawing molding (particularly deep drawing molding or overhang molding) by cold molding is performed. In addition, as a result of effectively suppressing or preventing breakage, delamination, pinholes, etc. of the metal foil, it is possible to obtain a highly reliable high-quality product (molded body).

In particular, the polyamide-based film of the present invention is excellent in thickness uniformity and excellent stress balance during elongation during secondary processing, even if it is extremely thin, for example, having a thickness of about 15 μm or less. As a result, the laminate obtained by laminating the film and the metal foil can obtain a product with higher output and smaller size by cold molding, which is also advantageous in terms of cost.

Further, according to the production method of the present invention, a polyamide-based film having the above-mentioned excellent properties can be efficiently and surely produced. In particular, even an extremely thin film having a thickness of about 15 μm or less can provide a film having excellent thickness uniformity. Moreover, when the resin is stretched at a relatively low temperature, the original characteristics of the resin can be maintained more effectively, and as a result, a film and a laminate more suitable for cold molding can be provided.

It is a schematic diagram which shows the outline of the manufacturing process and the cold working process of the polyamide film of this invention. It is a schematic diagram which shows the process of stretching an unstretched sheet by sequential biaxial stretching which concerns on the manufacturing method of this invention. It is a figure which shows the state which the stretching process by a tenter is seen from the direction a of FIG. It is a figure which shows the relationship between a direction and a physical property in a film. It is a figure which shows the sample for measuring the elastic modulus in a film. It is a figure which shows the method of measuring the average thickness in a film.

1. 1. Polyamide-based film The polyamide-based film of the present invention (the film of the present invention) is a polyamide-based film.
(1) The elastic modulus measured in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction as 0 degree from an arbitrary point on the film is 1.3 to 3 in each case. It is .5 GPa, and the difference between the maximum value and the minimum value of these elastic moduli is 0.5 GPa or less.
(2) Difference in molding work energy measured in the two directions of 0 degree and 90 degrees [(molding work energy up to 20% elongation in the 0 degree direction)-(up to 20% elongation in the 90 degree direction) Molding work energy)] is 0.02 Nm or less,
It is characterized by that.

(A) Material and composition of the film of the present invention
(A-1) Polyamide Resin The film of the present invention is a film containing a polyamide resin as a main component. A polyamide resin is a polymer formed by amide bonding of a plurality of monomers. Typical examples thereof include 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 12-nylon, poly (methaxylene adipamide) and the like. Further, for example, a binary copolymer such as 6-nylon / 6,6-nylon, 6-nylon / 6,10-nylon, 6-nylon / 11-nylon, 6-nylon / 12-nylon and the like is also used. be able to. Further, these may be mixed. Among the above, from the viewpoint of cold moldability, strength, cost, etc., a) a homopolymer of 6-nylon, b) a copolymer containing 6-nylon, or c) a mixture thereof is preferable.

The number average molecular weight of the polyamide resin is not particularly limited and can be changed depending on the type of the polyamide resin used and the like, but it is usually about 1000 to 40,000, particularly preferably 15,000 to 25,000. By using a polyamide resin within such a range, it becomes easier to stretch even at a relatively low temperature, and as a result, crystallization that may occur when stretching at a relatively high temperature and the resulting decrease in cold moldability are further improved. It can be definitely avoided.

The content of the polyamide resin in the film of the present invention is usually 90 to 100% by mass, preferably 95 to 100% by mass, and more preferably 98 to 100% by mass. As shown below, components other than the polyamide resin may be contained as long as the effects of the present invention are not impaired.

(A-2) Organic lubricant and inorganic lubricant (both are collectively referred to as "lubricant")
It is preferable that the film of the present invention 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 enhance the slipperiness more effectively. In particular, the coefficient of dynamic friction and the arithmetic mean height can be controlled within the optimum range. Further, in the present invention, in order to further improve the slipperiness of the film, it is preferable to contain both an organic lubricant and an inorganic lubricant in the polyamide-based film. Even when both are used in combination, the respective contents are preferably in the range of each content shown below.

The method of incorporating the lubricant in the film of the present invention is not particularly limited, and examples thereof include a method of preliminarily containing the lubricant in the polyamide resin used as a raw material, a method of adding the lubricant directly to the extruder at the time of kneading, and the like. Either one of these methods may be adopted, or two or more methods may be used in combination.

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

The carbon number of the bisamide composed of the fatty acid in the aliphatic bisamide-based lubricant is usually preferably in the range of 8 to 20, particularly preferably 12 to 18, and most preferably 16 to 18. preferable. When the number of carbon atoms exceeds 20, the slipperiness improving effect is sufficient up to the high humidity region, but the adhesiveness with the easy-adhesion layer may decrease or the adhesiveness with the adhesive at the time of laminating may decrease. There is. Further, when the number of carbon atoms is less than 8, sufficient slipperiness may not be obtained.

Examples of the carboxylic acid that can constitute an 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 amide based on these carboxylic acids, known ones or commercially available products can be used. For example, ethylene bisamide such as stearic acid amide, behenic acid amide, erucic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, ethylene bisbechenic acid amide, ethylene bis-erucic acid amide, hexamethylene bisstearate amide, hexa Methylenebisoleic acid amide Hexamethylene bisbechenic acid amide, hexamethylene bisuamide such as hexamethylene biserucic acid amide and the like can be mentioned. Among these, a lubricant containing at least one of ethylene bisstearic acid amide and ethylene bisbechenic acid amide is particularly preferable in that it has excellent compatibility with a polyamide resin.

As the organic lubricant, a powdery one can be used under normal temperature and pressure, but in the present invention, the organic lubricant is dissolved during melt-kneading, so that 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. If the content of the organic lubricant is less than 0.02% by mass, the effect of improving the slipperiness may not be sufficiently obtained. 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, so that the adhesiveness of the adhesive and the printing ink is lowered, and the adhesive and the adhesive at the time of lamination are used. In particular, when the adhesive strength is reduced, the cold moldability may be deteriorated. In the present invention, it is particularly desirable that the content of the above-mentioned organic lubricant is the total content of at least one of the aliphatic bisamide-based lubricants.

Inorganic lubricant The inorganic lubricant in the present invention is not limited, and includes, for example, silicon dioxide, clay, talc, mica, calcium carbonate, zinc carbonate, wallastonairo, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, and alumino. Examples thereof include magnesium silicate, zinc oxide, antimony trioxide, zeolite, kaolinite, aluminate, oxide-based glass and the like. Of these, silicon dioxide (particularly amorphous silicon dioxide) is particularly preferable.

The inorganic lubricant is usually in the form of a powder, but the average particle size thereof 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 slipperiness cannot be sufficiently obtained. On the other hand, if the average particle size exceeds 4.0 μm, the transparency may deteriorate.

The particle shape of the inorganic lubricant is not particularly limited, and may be, for example, spherical, flake-shaped, indefinite-shaped, balloon-shaped (hollow), or 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 size may be used, or two or more kinds of inorganic lubricants having different average particle sizes may be used.

The content of the inorganic lubricant in the polyamide film of the present invention is usually preferably 0.05 to 0.25% by mass, and more preferably 0.09 to 0.20% by mass. When the content of the inorganic lubricant is less than 0.05% by mass, the effect of improving the slipperiness by adding the inorganic lubricant cannot be sufficiently obtained. On the other hand, when the content of the inorganic lubricant exceeds 0.25% by mass, the surface of the film is too rough, so that the arithmetic mean height described later becomes too large, the ink adhesion is lowered, and the transparency of the film is deteriorated. Since it is lost, it may be difficult to impart designability by printing. In addition, there is a possibility that winding misalignment is likely to occur during film production. In the present invention, the content of the above-mentioned inorganic lubricant is silicon dioxide, clay, talc, mica, calcium carbonate, zinc carbonate, wallastonairo, 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., but usually, the weight ratio of organic lubricant: inorganic lubricant = It may be about 1: 0.1 to 1:10, preferably 1: 0.2 to 1: 5. By setting within such a range, slipperiness can be imparted more effectively.

(A-3) Other Components The film of the present invention may contain components other than the polyamide resin and the lubricant as long as the effects of the present invention are not impaired. For example, in addition to bending pinhole resistance improving agents such as polyolefins, polyamide elastomers, and polyester elastomers, various additives such as pigments, antioxidants, ultraviolet absorbers, preservatives, antistatic agents, and inorganic fine particles are used. One kind or two or more kinds may be added.

Further, as a method of adding various additives, a method of preliminarily containing them in the polyamide resin as a raw material, a method of directly adding them to an extruder, and the like can be mentioned, and one of these methods is adopted. You may use two or more methods together.

(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 basically be obtained by biaxial stretching. In particular, a biaxially stretched film using a roll and a tenter is suitable. The film of the present invention is controlled so as to have the following physical characteristics.

(B-1) Characteristics of Elastic Modulus and Work A value of the film of the present invention has A value to C value within a specific range as shown below as an index indicating the quality of stress balance during elongation in secondary processing. It is essential that it is controlled by.
(1) The elastic modulus (A value) measured in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction as 0 degree from an arbitrary point on the film is 1 .3 to 3.5 GPa, and the difference (B value) between the maximum and minimum values of these elastic moduli is 0.5 GPa or less.
(2) Difference in molding work energy measured in the two directions of 0 degree and 90 degrees [(molding work energy up to 20% elongation in the 0 degree direction)-(up to 20% elongation in the 90 degree direction) Molding work energy)] absolute value (C value) must be 0.02 Nm or less

The A value and the B value are indexes indicating that the elastic modulus is uniformly controlled over the entire film within a predetermined range. In particular, the A value indicates that it has an elastic modulus suitable for cold molding and the like. Further, the B value indicates that the smaller the value, the higher the uniformity of the elastic modulus.

The C value is the difference between the two when the molding work energy up to an elongation of 20% is measured in the two directions of 0 degree and 90 degree. This is based on the fact that the amount of work energy when the polyamide film is stretched during cold molding is generally equal to the respective molding work energy when the film is stretched to an elongation of 20%. In this case, the smaller the difference in molding work energy between the 0 degree direction and the 90 degree direction, the more uniform the moldability becomes.
Sufficient ductility can be obtained for the metal foil.

In the present invention, when at least one of the A value to the C value is out of the above range, the stress balance of the polyamide film in all directions is poor, and it becomes difficult to obtain uniform moldability. If uniform moldability cannot be obtained, for example, when a laminate obtained by laminating the film of the present invention and a metal foil is cold-molded, sufficient ductility is not imparted to the metal foil (that is, a polyamide-based film). Is difficult to follow the metal foil), so that problems such as breakage, delamination, and pinholes of the metal foil are likely to occur.

A value and B value The A value is usually 1.3 GPa to 3.5 GPa, more preferably 1.5 GPa to 3.2 GPa, and most preferably 1.7 GPa to 3.0 GPa. .. If the A value is less than 1.3 GPa, the flexibility becomes too high, so that sufficient ductility cannot be imparted to the metal foil, and the moldability deteriorates. On the other hand, if the A value exceeds 3.5 GPa, the flexibility becomes poor, so that breakage, delamination, etc. may occur during cold molding.

The B value is usually 0.5 MPa or less, and more preferably 0.4 MPa or less. If the B value exceeds 0.5 MPa, the variation in elastic modulus in the four directions of the film becomes large, so that the stress balance of the polyamide film in all directions becomes poor, and it becomes difficult to obtain uniform moldability. ..

The method for measuring the elastic modulus with respect to the A value and the B value may be carried out 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 reference direction (0 degree direction) of the film is arbitrarily set with an arbitrary point A on the film as a center point. The measurement direction is 45 degree direction (b), 90 degree direction (c) and 135 degree direction (d) clockwise from the reference direction (a), and from the center point A to each measurement direction. The sample is cut into strips of 100 mm and 15 mm in the direction perpendicular to the measurement direction. For example, as shown in FIG. 5, in the 0 degree direction, the sample 41 (length 100 mm × width 15 mm) is cut out in the range of 30 mm to 130 mm from the center point A. Cut the sample in the same way in the other directions. These samples were measured at a tensile speed of 25 mm / min using a tensile tester (AG-1S manufactured by Shimadzu Corporation) equipped with a load cell for 1 kN measurement and a sample chuck, and the gradient of the load-elongation curve. Each elastic modulus is calculated from. The above reference direction can be set to the reference direction (0 degree direction) when the MD in the stretching step at the time of film production is known.

C value The C value is usually 0.02 N · m or less, preferably 0.01 N · m or less, and more preferably 0.008 N · m or less. If the C value exceeds 0.02 N · m, for example, the difference in the amount of molding work energy during cold molding becomes large in each direction of the film, which makes uniform molding difficult. Therefore, when the laminate obtained by laminating the polyamide film of the present invention and the metal foil is cold-molded, the metal foil is not imparted with uniform ductility, and the metal foil is liable to break, delaminate, pinhole, or the like. Become.

Regarding the C value, the measurement of molding work energy up to 20% elongation is performed by measuring the stroke and stress every 0.05 seconds in the uniaxial tensile test, and 0.05 obtained from 0% elongation to 20% elongation. It is the sum of the product of the stroke and stress every second. More specifically, the elongation 0% is set to 0 seconds, the stress value and the stroke for 0.05 seconds are measured every 0.05 seconds until the elongation reaches 20%, and the product (area) of each is measured. The value obtained by adding all the obtained products (areas) was taken as the C value.

(B-2) Dynamic friction coefficient (slipperiness)
The coefficient of kinetic friction of the film of the present invention is not limited, but is particularly preferably 0.60 or less, and more preferably 0.50 or less. By controlling the coefficient of kinetic friction to 0.60 or less, slipperiness is improved even when cold molding is performed in an environment of high humidity (for example, humidity of 90% or more), for example, wrinkles, delamination, and pinholes. Etc. can be effectively suppressed or prevented. If the coefficient of kinetic friction exceeds 0.60, the slipperiness during cold molding becomes insufficient, and especially when cold molding is performed in a high humidity environment, wrinkles may occur or delamination may occur. In addition, it becomes difficult to uniformly mold the entire laminate, and pinholes are likely to occur. The lower limit of the dynamic friction coefficient is not limited, but may be, for example, about 0.05.

The dynamic friction coefficient in the present invention was measured according to JIS K7125. More specifically, a sample of a polyamide film was humidity-controlled at 23 ° C. × 50% RH for 2 hours, and then measurements were carried out under the same temperature and humidity conditions. In the case of a laminated body containing the film of the present invention as the outermost layer, the surface to be the outermost layer was used as the measurement surface. In the calculation of the dynamic friction coefficient, two samples are taken for each of the four directions specified in the measurement of (B-1) stress characteristics, and a total of eight points are measured and used as the average value.

(B-3) Arithmetic mean height (surface roughness)
The film of the present invention has an arithmetic mean height Sa (hereinafter simply referred to as "Sa"), which is one index showing excellent moldability (slipperiness) during cold molding, of 0.01 to. It is preferably 0.15, more preferably 0.02 to 0.10, and even more preferably 0.03 to 0.07. When Sa is less than 0.01, sufficient slipperiness cannot be obtained during cold molding, so that wrinkles, delamination, etc. are likely to occur when the mold is pushed during cold molding. On the other hand, when Sa exceeds 0.15, the slipperiness is good, but when the amount of inorganic particles added is large, the surface becomes rough and the transparency may be lost.

The Sa measurement in the present invention was performed using an ultra-precision non-contact three-dimensional surface disposition measuring machine "Tarisurf CCI6000" manufactured by TayLoHobson. More specifically, a sample of a polyamide film was humidity-controlled at 20 ° C. × 65% RH for 2 hours, and then measurements were carried out under the same temperature and humidity conditions. In the case of a laminated body containing the film of the present invention as the outermost layer, the surface to be the outermost layer was used as the measurement surface. The sample shall be cut into a size of 100 mm × 100 mm, and 10 points shall be measured at random (n = 10), and the average value thereof shall be used.

(B-4) Average Thickness and Thickness Accuracy The film of the present invention usually has a standard deviation of 0 with respect to the average thickness in the eight directions shown below as an index indicating that the thickness accuracy (thickness uniformity) is extremely high. It is .200 μm or less, particularly preferably 0.180 μm or less, and more preferably 0.160 μm or less. When the standard deviation indicating the above 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 film thickness is about 15 μm or less, it is bonded to the metal foil. It is possible to obtain good moldability without causing problems such as delamination and pinholes when the laminated body is formed and cold-molded by deep drawing. If the standard deviation exceeds 0.200 μm, the thickness accuracy will be low, and as a result, especially if the thickness of the film is small, it will not be possible to impart sufficient ductility to the metal foil when it is bonded to the metal foil. Occurrence of lamination or pinholes becomes remarkable, and good moldability may not be obtained.

The evaluation method of the thickness accuracy is performed as follows. After adjusting the humidity of the polyamide film at 23 ° C. × 50% RH for 2 hours, as shown in FIG. 6, a reference direction (0 degree direction) is specified with an arbitrary point A on the film as the center point, and then 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) clockwise with respect to the reference direction. ), A total of eight 100 mm straight lines L1 to L8 are drawn in eight directions of the 270 degree direction (g) and the 315 degree direction (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 Co., Ltd.) (measurement at 10 points). FIG. 6 shows, as an example, a state in which measurement points (10 points) are taken when measuring L2 in the 45-degree direction. Then, the average value of the measured values of a total of 80 points of data obtained by measuring on all the straight lines is calculated, and this is used as the average thickness to calculate the standard deviation with respect to the average thickness. The above reference direction can be set to the MD when the MD in the stretching step at the time of film production is known.

In the present invention, the average thickness and standard deviation may be measured based on any one point (point A) of the polyamide film, but in particular, the polyamide film wound on the obtained film roll. In all of the following three points, it is more desirable that the average thickness and standard deviation are within the above range. These 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) winding. It is near the left end of the width and near the end of the winding.

The average thickness of the film of the present invention may generally be set within the range of 30 μm or less, but is particularly preferably set within the range of 25 μm or less. More specifically, it is preferably 16 μm or less, particularly 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 molding. However, biaxial stretching using a tenter as described later is subject to specific conditions. By performing under satisfactory stretching conditions, a biaxially stretched film having excellent thickness accuracy (thickness uniformity) and excellent stress balance during stretching in the above four directions can be obtained even if the film has a small thickness. Can be done.

If the average thickness of the film exceeds 30 μm, the moldability of the polyamide-based film itself deteriorates, which may make it difficult to use as a small battery exterior material, and 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, the ductility imparted to the metal foil when bonded to the metal foil tends to be insufficient, and the moldability is inferior. Therefore, it is usually sufficient to set it to about 2 μm.

The polyamide-based film of the present invention is preferably a laminate bonded to a metal foil and used for cold molding. However, when the polyamide-based film of the present invention satisfying the above characteristics is used, the metal foil is used. Can be imparted with sufficient malleability. Due to this effect, moldability during cold molding (among these, during drawing molding (particularly deep drawing molding)) is improved, breakage of the metal foil can be prevented, and problems such as delamination and pinholes occur. Can also be suppressed or prevented.

The smaller the thickness of the polyamide film, the more difficult it becomes to impart sufficient ductility to the metal foil. In particular, in an extremely thin film of 20 μm or less, the stress at the time of elongation varies and the thickness accuracy is low, so that the polyamide film or the metal foil is significantly broken by the pushing force at the time of cold molding. That is, the thinner the film, the larger the variation in stress during elongation tends to be, and the greater the variation in thickness tends to be, so that higher control is required.

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

On the other hand, in the present invention, by adopting a specific manufacturing method as shown later, even if the thickness is about 15 μm or less (particularly about 12 μm or less), the stress at the time of extension in the above four directions We have succeeded in providing a polyamide-based film having an excellent balance and a high uniformity of thickness. As a result of being able to provide such a special polyamide-based film, when a laminate laminated with a metal foil is used, for example, as an exterior body of a battery (for example, a lithium ion battery), for example, the number of electrodes and the capacity of an electrolytic solution can be increased. It can also contribute to the miniaturization and cost reduction of the battery itself.

(B-5) Stress Characteristics The film of the present invention has (3) 0 degrees in a specific direction from an arbitrary point on the film, and in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to that direction. The difference (D value) between the maximum value and the minimum value of each stress at 5% elongation by the uniaxial tensile test is 35 MPa or less, and (4) each at 15% elongation by the uniaxial tensile test in the above four directions. The difference (E value) between the maximum value and the minimum value of stress is preferably 40 MPa or less. That is, it is preferable that the D value and the E value are also satisfied as an index indicating that the stress balance at the time of elongation in the secondary processing is excellent.

If the D value and the E value exceed the above range, the stress balance of the polyamide film in all directions is poor, and it may be difficult to obtain uniform moldability. When uniform moldability cannot be obtained, for example, when a laminate obtained by laminating the film of the present invention and a metal foil is cold-molded, sufficient ductility is not imparted to the metal foil (that is, the polyamide-based film is a metal foil. Because it becomes difficult to follow), the metal foil is liable to break, or defects such as delamination and pinholes are likely to occur.

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

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

The stresses in the four directions at the time of 5% elongation are not particularly limited, but are preferably in the range of 35 to 130 MPa and in the range of 40 to 90 MPa in terms of cold moldability of the laminate. It is more preferable, and most preferably it is in the range of 45 to 75 MPa.

The stresses in the four directions at the time of 15% elongation are not particularly limited, but are preferably in the range of 55 to 145 MPa and in the range of 60 to 130 MPa in terms of cold moldability of the laminate. It is more preferable, and most preferably it is in the range of 65 to 115 MPa.

In the film of the present invention, if the stresses in the four directions at the time of 5% and 15% elongation do not satisfy the above range, sufficient cold moldability 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 reference direction (0 degree direction) of the film is arbitrarily set with an arbitrary point A on the film as a center point. The measurement direction is 45 degree direction (b), 90 degree direction (c) and 135 degree direction (d) clockwise from the reference direction (a), and from the center point A to each measurement direction. The sample is cut into strips of 100 mm and 15 mm in the direction perpendicular to the measurement direction. For example, as shown in FIG. 5, in the 0 degree direction, the sample 41 (length 100 mm × width 15 mm) is cut out in the range of 30 mm to 130 mm from the center point A. Cut the sample in the same way in the other directions. For these samples, a tensile tester (AG-1S manufactured by Shimadzu Corporation) equipped with a load cell for 50N measurement and a sample chuck was used to apply stress at 5% and 15% elongation at a tensile speed of 100 mm / min. Measure each. When the MD in the stretching step at the time of film production is known, the above reference direction is set to the MD as the reference direction.

The polyamide-based film of the present invention satisfying the above-mentioned characteristic values is preferably obtained by a biaxial stretching method including a step of stretching with a tenter in at least one direction in the longitudinal direction and the lateral direction.

Generally, as a biaxial stretching method, a simultaneous biaxial stretching method in which a longitudinal and lateral stretching steps are simultaneously performed, and a sequential biaxial stretching method in which a longitudinal stretching step is performed and then a lateral stretching step is performed. There is a way. In the above description, the vertical direction is exemplified as the first 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 viewpoint of the degree of freedom in setting stretching conditions. Therefore, it is preferable that the film of the present invention is obtained by sequential biaxial stretching including a step of stretching in at least one direction in the longitudinal direction and the lateral direction by a tenter. In particular, it is desirable that the film of the present invention be produced by the production method of the present invention described later.

(B-6) Haze (transparency)
As an index showing that the film of the present invention is excellent in transparency, the haze is preferably 12% or less, more preferably 10% or less, further preferably 8% or less, and most preferably 6% or less. preferable. If the haze exceeds 12%, the transparency of the film is lost, which may make it difficult to impart designability by printing. The lower limit of the haze is not particularly limited, but is usually about 1.0%.

The haze in the present invention was measured using a haze meter "NDH4000" manufactured by Nippon Denshoku Kogyo Co., Ltd. More specifically, a sample of a polyamide film was humidity-controlled at 23 ° C. × 50% RH for 2 hours, and then measurements were carried out under the same temperature and humidity conditions. In the case of a laminated body containing the film of the present invention as the outermost layer, the surface to be the outermost layer was used as the measurement surface. The number of measured samples is n = 10, and the average value thereof is used.

(C) Laminated film containing the film of the present invention The film of the present invention can be used for various purposes in the same manner as a known or commercially available polyamide-based film. In this case, the film of the present invention can be used as it is or in a surface-treated state, or it can be used in the form of a laminated body obtained by laminating other layers.

When taking the form of a laminated body, a typical example thereof is a laminated body containing the film of the present invention and a metal foil laminated on the film (the laminated body of the present invention). In this case, the film of the present invention and the metal foil may be laminated so as to be in direct contact with each other, or may be laminated with another layer interposed therebetween. In particular, in the present invention, a laminated body 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 layers.

The film of the present invention can be used as it is, but it is particularly preferable to have a primer layer (anchor coat layer: AC layer) on at least one surface or a part of the film surface. When forming such a primer layer, if an adhesive is applied to the surface of the film having the primer layer and the metal foil is attached, the adhesiveness between the polyamide film and the metal foil can be further enhanced. Thereby, sufficient ductility can be imparted to the metal foil. Therefore, in addition to making the polyamide film or metal foil less likely to break, it is possible to more effectively prevent the occurrence of delamination, pinholes, and the like. A film containing such a primer layer is also included in the polyamide-based film of the present invention. The details of the primer layer will be described in the following <Primer layer embodiment>.

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 alloy, etc.), and other components are known as specified in JIS, etc., as long as the moldability of the laminate is not impaired. Any component may be contained as long as it is within the content range.

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

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

Further, in the laminate of the present invention, one or more other layers are laminated on the exterior side (the surface different from the surface to be bonded to the metal foil) of the film of the present invention constituting the laminate, depending on the purpose of use and the like. You may. The other layer is not particularly limited, but for example, a polyester film is preferable. By laminating the polyester film, heat resistance, withstand voltage, chemical resistance and the like can be enhanced, and peeling strength can also be enhanced.

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 of each layer. For example, it is desirable that each layer is laminated using an adhesive layer such as a urethane adhesive layer or an acrylic adhesive layer between the polyamide film / metal foil and the metal foil / sealant film.

In this case, when the polyamide-based film of the present invention has a primer layer on at least one surface of the film surface, it is preferable that a metal foil is laminated on the primer layer surface. More specifically, it is preferable that the metal foil is laminated on the surface of the primer layer via an adhesive layer such as a urethane-based adhesive layer or an acrylic-based adhesive layer.

Since the laminate of the present invention contains the film of the present invention in particular, it can be suitably used for draw molding (particularly deep drawing molding or overhang molding) which is cold molding. Here, drawing molding is basically a method of molding a bottomed container having a shape such as a cylinder, a square cylinder, or a cone from one laminated body. Such containers are generally characterized by being seamless.

(D) Container containing the laminate of the present invention The present invention also includes a container containing the laminate of the present invention. For example, a container molded using the laminate of the present invention is also included in the present invention. Of these, a container obtained by cold molding is preferable. In particular, a container manufactured by drawing (drawing) or overhanging (overhanging) as cold molding is preferable, and a container manufactured by drawing 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 is preferably produced by a method for producing a container, which comprises a step of cold-molding the laminate. Can be done. Therefore, for example, a seamless container or the like can be manufactured from the laminate of the present invention.

The cold molding method itself in this case is not limited, and can be carried out according to a known method. For example, a method of molding as a solid without melting the resin contained in the laminate may be adopted. The temperature at the time of molding may be room temperature, but is preferably 50 ° C. or lower, particularly 20 to 30 ° C.

As a more specific molding method (processing method), for example, drawing processing such as cylindrical drawing processing, square cylinder drawing processing, irregular drawing processing, conical drawing processing, pyramid drawing processing, and spherical head drawing processing can be preferably adopted. .. Further, the drawing process is classified into shallow drawing process and deep drawing process, and the laminate of the present invention can be particularly applied to 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 arranging the laminate of the present invention between the die and the blank holder and b) the punch is pushed into the laminate to be deformed into a container shape. The drawing process can be carried out by a method including a step of causing the drawing.

The container thus obtained can be highly reliable because defects such as breakage of the metal foil, delamination, and pinholes are effectively suppressed. Therefore, the container according to the present invention can be used for various purposes including packaging materials for various industrial products. In particular, a molded body formed by deep drawing is preferably used as an exterior body of a lithium ion battery, and a molded body formed by overhang molding is preferably used as a press-through pack or the like.

<Primer layer embodiment>
The primer layer in the polyamide film of the present invention preferably has the following embodiments.

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

As the primer layer, a layer containing various synthetic resins such as polyurethane resin and acrylic resin can be adopted. In particular, a primer layer containing a polyurethane resin is preferable. As such a polyurethane resin, for example, it is preferable to contain an anionic water-dispersible polyurethane resin. The primer layer containing this resin can be formed by applying an aqueous coating agent containing the resin to the surface of a polyamide film.

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

The anionic water-dispersible polyurethane resin used in the present invention has an anionic functional group introduced into the polyurethane resin. Examples of the method for introducing an anionic functional group into the polyurethane resin include a) a method using a 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. And so on.

Examples of the diol having an anionic functional group include glyceric acid, dioxymaleic acid, dioxyfumaric acid, tartrate acid, dimethylol propionic acid, dimethylol butanoic acid, 2,2-dimethylol valeric acid, and 2,2-dimethylol pentanoic acid. , 4,4-Di (hydroxyphenyl) valeric acid, 4,4-di (hydroxyphenyl) butyric acid and other aliphatic carboxylic acids, as well as 2,6-dioxybenzoic acid and other aromatic carboxylic acids.

When dispersing an anion-type polyurethane resin in water, it is generally preferable to use a volatile base. The volatile base is not particularly limited, and known ones 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 boiling point is relatively low, so that the amount remaining in the primer layer is small.

In the present invention, a commercially available anionic water-dispersible polyurethane resin can be preferably used for forming the primer layer. Examples of such commercially available anionic water-dispersible polyurethane resins include "Hydran ADS-110", "Hydran ADS-120", "Hydran KU-400SF", "Hydran HW-311", and "Hydran" manufactured by DIC. HW-321B ”,“ Hydran HW-333 ”,“ Hydran AP-20 ”,“ Hydran AP-201 ”,“ Hydran APX-101H ”,“ Hydran AP-60LM ”,“ Superflex ”manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. 107M ”,“ Super Flex 150 ”,“ Super Flex 150HS ”,“ Super Flex 410 ”,“ Super Flex 420NS ”,“ Super Flex 460 ”,“ Super Flex 460S ”,“ Super Flex 700 ”,“ Super Flex 750 ” , "Super Flex 840", "Take Rack W-6010", "Take Rack W-6020", "Take Rack W-511", "Take Rack WS-6021", "Take Rack WS-6021", DSM Co., Ltd. "NeoRez R9679", "NeoRez R9637", "NeoRez R966", "NeoRez R972" and the like.

In the polyamide film of the present invention, it is preferable that the primer layer contains a curing agent such as a melamine resin for the purpose of improving the water resistance, heat resistance and the like of the primer layer. The content of the curing agent such as melamine resin is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the anionic water-dispersible polyurethane resin.

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

The solid content concentration of the anionic water-dispersible polyurethane resin in the aqueous coating material can be appropriately changed depending on the specifications of the coating device, the drying / heating device, etc. However, if the solution is too dilute, a long time is required in the drying process. Is likely to cause the problem. On the other hand, if the solid content concentration is too high, it is difficult to obtain a uniform coating agent, which tends to cause a problem in coatability. From this point of view, 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.

In addition to the anionic water-dispersible polyurethane resin that is the main component, the water-based coating agent includes, for example, a defoaming agent, a surfactant, etc. in order to improve the coatability when the water-based coating agent is applied to the film. Additives may be added.

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

Furthermore, various additives such as antistatic agents and slip agents can be added to the water-based coating agent, if necessary, as long as they do not affect the adhesiveness.

2. Method for Producing Film of the Present Invention The production method of the present invention is a method for producing a biaxially oriented polyamide-based film.
(1) A sheet molding step of obtaining an unstretched sheet by molding a melt-kneaded product containing a polyamide resin into a sheet.
(2) A stretching step of obtaining a stretched film by sequentially or simultaneously biaxially stretching the unstretched sheet to MD and TD is included, and
(3) The following formulas a) and b);
a) 0.85 ≤ X / Y ≤ 0.95
b) 8.5 ≤ X x Y ≤ 9.5
(However, X indicates the stretching ratio of the MD, and Y indicates the stretching ratio of the TD.)
Meet both
It is characterized by that.

Sheet molding step In the sheet molding step, an unstretched sheet is obtained by molding a melt-kneaded product containing a polyamide resin into a sheet.

As the polyamide resin, various materials as described above can be used. In addition, various additives can also be contained in the melt-kneaded product. From the viewpoint that the dynamic friction coefficient and the like can be effectively controlled, the production method 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. As these lubricants, those described above can be adopted.

The preparation of the melt-kneaded product itself may be carried out according to a known method. For example, a raw material containing a polyamide resin is put into an extruder equipped with a heating device, melted by heating to a predetermined temperature, and then the melt-kneaded product is extruded by a T-die and cooled and solidified by a casting drum or the like. An unstretched sheet, which is a sheet-shaped molded product, can be obtained.

The average thickness of the unstretched sheet in this case is not particularly limited, but is generally about 15 to 250 μm, and particularly preferably 50 to 235 μm. By setting within such a range, the stretching step can be carried out more efficiently.

Stretching Step In the stretching step, 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. This makes it possible to obtain a more uniform film thickness.

The tenter itself is a device that has been conventionally used for stretching a film, and is a device that widens the unstretched sheet in the vertical and / or horizontal directions while grasping both ends. Even when a tenter is used, there are two methods, 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 and at the same time to TD while grasping both ends of the unstretched film. On the other hand, sequential biaxial stretching using a tenter is a method in which 1) MD is stretched by passing an unstretched sheet through a plurality of rolls having different rotation speeds, and then the stretched film is stretched to TD by a tenter. ) There is a method of stretching the MD of the unstretched sheet with a tenter and then stretching the stretched film to the TD with a tenter, but the method of 1) above is particularly important in terms of the physical properties and productivity of the obtained film. preferable. Regarding the method 1), the unstretched film is sequentially biaxially stretched by the process as shown in FIG.

First, as shown in FIG. 2, the unstretched sheet 13 is stretched in the MD (longitudinal direction) by passing through the plurality of rolls 21. Since these plurality of rolls have different rotation speeds, the unstretched sheet 13 is stretched to 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 FIG. 2, the number of rolls is 5, but in reality, the number may be other than that. Further, as the roll, for example, rolls having different functions from each other may be installed in the form of a preheating roll, a stretching roll and a cooling roll in this order. The number of rolls having each of these functions can also be set as appropriate. Further, when a plurality of stretching rolls are provided, the setting may be such that stretching can be performed in multiple stages. For example, the draw ratio of MD can be appropriately set within the range of (E1 × E2) by two-step stretching 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 through 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 gripped by a clip connected to a link device 34 fixed to a guide rail at both ends near the entrance. , Passes through the preheating zone 31, the stretching zone 32, and the relaxation heat treatment zone 33 in the order of flow direction. The first stretched film 13'is heated to a constant temperature in the preheating zone 31 and then stretched to TD in the stretching zone 32. After that, in the relaxation heat treatment zone 33, the relaxation treatment is performed at a constant temperature. In this way, the second stretched film 14 (the film of the present invention) is obtained. After that, the link device 34 fixed to the guide rail is removed from the second stretched film 14 near the outlet of the tenter 22, and returned to the vicinity of the inlet of the tenter 22.

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

In the production method of the present invention, the following formulas a) and b);
a) 0.85 ≤ X / Y ≤ 0.95 (preferably 0.89 ≤ X / Y ≤ 0.93)
b) 8.5 ≤ X x Y ≤ 9.5 (preferably 8.7 ≤ X x Y ≤ 9.1)
(However, X indicates the stretching ratio of the MD, and Y indicates the stretching ratio of the TD.)
It is essential to meet both of the above.

If either of the above conditions a) and b) is not satisfied, the resulting polyamide-based film has an unbalanced stress in four directions, making it difficult to obtain the film of the present invention.

As for the temperature conditions in the stretching step, for example, when performing the simultaneous biaxial stretching, it is preferable to stretch in a temperature range of 180 ° C. to 220 ° C. Further, for example, when the sequential biaxial stretching is performed, the MD may be stretched in a temperature range of 50 to 120 ° C. (particularly 50 to 80 ° C., further 50 to 70 ° C., and further 50 to 65 ° C.). Preferably, the stretching of the TD is carried out in a temperature range of 70 to 150 ° C. (particularly 70 to 130 ° C., further 70 to 120 ° C., and further 70 to 110 ° C.). By controlling the temperature within such a range, the film of the present invention can be produced more reliably. These temperatures can be set and controlled while preheating in, for example, the roll 21 (preheating roll) shown in FIG. 2, the preheating zone 31 of the tenter shown in FIG. 3, and the like.

Further, in both simultaneous biaxial stretching and sequential biaxial stretching using a tenter, it is preferable to perform relaxation heat treatment after stretching. The relaxation heat treatment preferably has a relaxation rate of 2 to 5% in a 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.

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

<Embodiment in the stretching step>
As the stretching step in the present invention, a sequential biaxial stretching step of stretching the MD with a roll and stretching the TD with a tenter can be preferably adopted. By adopting this method and satisfying the temperature conditions shown below, it is possible to improve the uniformity of thickness and the stress balance at the time of extension in the above four directions. 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 set to among others 50-65 ° C..

The MD is preferably stretched in two or more stages. In this case, it is preferable to increase the draw ratio step by step. That is, it is preferable to control so that the extension ratio of the (n + 1) stage is higher than the extension bridge ratio of the nth stage. As a result, the whole can be stretched more uniformly. For example, in the case of stretching in two stages, the first stage has a draw ratio of 1.1 to 1.2, and the second stage has a draw ratio of 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 the stretching of the MD. In particular, it is preferable to raise the temperature sequentially along the film taking-up direction, and the temperature gradient (the temperature T1 at the beginning (inlet) and the temperature at the end (outlet) of the film in the traveling direction) of 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 (entrance) to the end (exit) of the running direction of the film is usually preferably 1 to 5 seconds, and more particularly preferably 2 to 4 seconds. preferable.

Stretching of TD Stretching of TD is carried out 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.

Further, it is preferable that the temperature of the stretched zone 32 is gradually increased along the film taking-up direction, and the temperature gradient (the temperature T1 at the beginning (entrance) of the film running direction and the end (exit) in the entire stretched zone). ) Is usually preferably 5 ° C. or higher, and more preferably 8 ° C. or higher. At this time, the traveling time (heating time) of the film from the beginning (entrance) to the end (exit) of the film in the traveling direction in the stretching zone 32 is preferably 1 to 5 seconds, particularly 2 to 4 seconds. 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 the polyamide-based film of the present invention having a primer layer on at least one side of the film surface, it is preferable to carry out the same stretching method and stretching conditions as described above. In order to form a primer layer on the film surface, it is preferable to apply an aqueous coating agent to the polyamide-based film after stretching to MD in the above-mentioned production method. Then, it is preferable that the film is subsequently stretched to TD together with an aqueous coating under the same stretching conditions as described above (in-line coating). The amount of the aqueous coating agent applied is preferably adjusted so that the thickness of the primer layer formed on the film surface after stretching is 0.01 to 0.10 μm.

In the production method of the present invention, it is desirable that no stretching method other than the above is adopted as the stretching step from the viewpoint of maintaining the uniformity of thickness. For example, it is desirable not to include the stretching step by the tubular method (inflation method).

Examples and comparative examples are shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples.

Example 1
(1) Production of Polyamide-based Film First, the components shown in Table 1 were used as raw materials.

Using the above raw materials, melt in an extruder at a composition ratio of polyamide resin (polyamide 6 resin) / silica-containing polyamide resin / fatty acid-containing polyamide resin = 91.5 parts by mass / 2.5 parts by mass / 6.0 parts by mass. An unstretched sheet was produced by kneading, supplying it to a T-die, discharging it into a sheet, winding it on a metal drum whose temperature was adjusted to 20 ° C., cooling it, 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.

Next, the obtained unstretched sheet was subjected to a stretching step by sequentially biaxially stretching. More specifically, in the apparatus shown in FIG. 2, MD was stretched using a roll, and then TD was stretched using a tenter.

First, the MD was stretched to the MD so that the total stretching ratio was 2.85 times by passing the sheet through a plurality of rolls. 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 = It was set to 2.85 times. As for the heating conditions, the film was stretched by providing a temperature gradient so that the beginning (T1) of the traveling direction was 54 ° C. and the end (T2) was 57 ° C. along the taking-up direction of the film. At this time, the running time (heating time) of the film from the beginning (entrance) to the end (exit) of the running direction of the film was about 3 seconds.

Next, the stretching of TD was carried out using a tenter as shown in FIG. First, while preheating was performed with the temperature of the preheating zone 31 (preheating portion) set to 65 ° C., the stretch zone 32 was stretched 3.2 times to TD. At this time, in the stretched zone 32 (stretched portion), a temperature gradient was provided so that the beginning (T1) of the traveling direction was 74 ° C. and the end (T2) was 96 ° C. along the taking-up direction of the film. At this time, the running time (heating time) of the film from the beginning (entrance) to the end (outlet) of the running direction of the film in the stretching zone 32 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) under the conditions of 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 into a roll.

(2) Preparation of Laminated Body 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 (aluminum foil having a thickness of 50 μm) was attached to the adhesive-coated surface. Next, after applying the above adhesive to the aluminum foil side of the laminate of the polyamide film and the aluminum foil under the same conditions, a sealant film (unstretched polypropylene film (GHC thickness 50 μm manufactured by Mitsui Chemicals Tohcello Co., Ltd.)) was applied to the coated surface. )) Are laminated and aged for 72 hours in an atmosphere of 40 ° C. to prepare a laminate (polypropylene film / aluminum foil / sealant film).

Examples 2-35, Comparative Examples 1-16
The composition of the raw materials is changed so that the production conditions and the target thickness of the polyamide film after stretching are changed to those shown in Tables 2 to 4, and the content of the organic lubricant or the inorganic lubricant is 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, with respect to Example 7 and Example 17, more specifically, the following changes were made.

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

(2) Example 17 Using the raw materials shown in Table 1, polyamide resin (polyamide 6 resin) / polyamide resin (polyamide 66 resin) / silica-containing polyamide resin / fatty acid-containing polyamide resin = 81.8 / 9.7 / A polyamide-based film was obtained in the same manner as in Example 1 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 2. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 1.

Test Example 1
The physical characteristics of the polyamide films and laminates obtained in Examples 1 to 35 and Comparative Examples 1 to 16 were evaluated. The evaluation results are shown in Tables 5-10. The methods for measuring and evaluating various physical properties were as follows.

(1) Elastic modulus of polyamide film (GPa)
The elastic modulus of the polyamide film was measured and calculated by the above method in each direction.

(2) Molding work energy (Nm) up to 20% elongation of polyamide film
The molding work energy of the polyamide film up to an elongation of 20% was measured and calculated by the above method in the MD direction and the TD direction, respectively.

(3) Average thickness (μm) and standard deviation (μm) of polyamide film
The average thickness and standard deviation of the polyamide film were measured and calculated by the above methods, respectively. The sample films used for the measurement were the following three types.
In the polyamide-based film wound on the obtained film roll, a) the film collected near the center of the winding width and at a position corresponding to half of the winding amount is indicated as "A", and b) the winding width. The one collected near the right end of the winding and at the position corresponding to half of the winding amount is indicated as "B", and c) the one collected near the left end of the winding width and near the end of the winding is Notated as "C".

(4) Polyamide-based film dynamic friction coefficient, haze (%), arithmetic mean height Sa (μm)
The coefficient of dynamic friction, haze, and arithmetic mean height Sa of the polyamide film were measured by the method shown above. As the sample film used for the measurement, a polyamide-based film wound on the obtained film roll, which was collected near the center of the winding width and at a position corresponding to half of the winding amount, was used. ..

(5) Thickness (μm) of primer layer (anchor coat layer: AC layer)
The obtained polyamide film was embedded in an epoxy resin, and a section having a thickness of 100 nm was collected by a frozen ultramicrotome. The cutting temperature was −120 ° C. and the cutting speed was 0.4 mm / min. The collected sections were stained for 1 hour vapor in RuO ₄ solution, using a JEM-1230 TEM (manufactured by JEOL) to measure the primer layer thickness at an accelerating voltage 100kV by a transmission measurement. At this time, 5 arbitrary points were selected for measuring the thickness of the primer layer, and the average value of the measured values at the 5 points was taken as the thickness.
As the sample film used for the measurement, a polyamide-based film wound on the obtained film roll, which was collected near the center of the winding width and at a position corresponding to half of the winding amount, was used. ..

(5) Moldability and moisture resistance of the laminate 1) Moldability (drawing depth; Eriksen test) (mm)
Based on JISZ2247, a steel ball punch was pressed against the obtained laminate with a predetermined pressing depth using an Eriksen testing machine (No. 5755 manufactured by Yasuda Seiki Seisakusho Co., Ltd.) to obtain an Eriksen value. The Eriksen value was measured every 0.5 mm. It was determined that the case where the Eriksen value is 5 mm or more is preferable, and the case where the Eriksen value is 8 mm or more is particularly suitable for deep drawing. The pushing speed of the steel ball punch was 0.20 mm / s, and the measurement environment was 20 ° C. × 90% RH.

2) Moisture and 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 using a high temperature and high pressure cooking sterilizer RCS-60SPXTG (manufactured by Hisaka Works). After the treatment at 1.8 kg / cm ² , the Eriksen test similar to 1) above was performed. At this time, when the Eriksen value is 7 mm or more, "◎", when the Eriksen value is 6 mm or more and less than 7 mm, "○", when the Eriksen value is 5 mm or more and less than 6 mm, "△", the Eriksen value. When is less than 5 mm, it is indicated as "x".

In Tables 5 to 10, the unit of average thickness is "μm", the unit of thickness of the primer layer is "μm", the unit of stress is "MPa", the unit of elasticity is "GPa", and the unit of molding work energy. Indicates "Nm", the unit of haze value is "%", the unit of arithmetic average roughness is "μm", and the unit of drawing depth is "mm".

As is clear from these results, in Examples 1 to 35, the draw ratio of the polyamide-based film was in a predetermined range, so that the obtained polyamide-based film had an elastic characteristic measured in the above four directions. Is 1.3 to 3.5 GPa, the difference between the maximum value and the minimum value of these elastic characteristics is 0.5 GPa or less, and the molding work energy measured in the above two directions of 0 degree and 90 degree. The absolute value of the difference [(molding work energy up to 20% elongation in the 0 degree direction)-(molding work energy up to 20% elongation in the 90 degree direction)] is 0.02 Nm or less. It became the one that satisfied the physical characteristics. The laminate obtained by using these polyamide films had uniform ductility in all directions when cold-molded. That is, it can be seen that the polyamide-based film of each example has excellent moldability without breaking the aluminum foil, causing delamination, pinholes, and the like.

On the other hand, Comparative Examples 1 to 16 did not satisfy the range of physical properties required for the film of the present invention, so that the laminate obtained by using the polyamide-based film of these Comparative Examples was cold-molded. It was confirmed that the film could not have uniform ductility in all directions and was inferior in moldability.

Example 36
(1) Production of Polyamide-based Film Using the raw materials shown in Table 1, polyamide resin (polyamide 6 resin) / silica-containing polyamide resin / fatty acid-containing polyamide resin = 91.5 parts by mass / 2.5 parts by mass / 6.0 mass It was melt-kneaded in the extruder at the composition ratio of the part, supplied to the T-die, and discharged in the form of a sheet. An unstretched sheet was produced by winding the sheet around a metal drum whose temperature was adjusted to 20 ° C., cooling the sheet, and winding the sheet. 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.

Next, the obtained unstretched sheet was subjected to a stretching step by sequentially biaxially stretching. More specifically, using an apparatus as shown in FIG. 2, the MD of the sheet was stretched using a roll, and then the TD was stretched by a method of stretching using a tenter.

First, the MD was stretched to the MD so that the total stretching ratio was 2.85 times by passing the sheet through a plurality of stretching rolls. 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 = It was set to 2.85 times. As for the heating conditions, the film was stretched by providing a temperature gradient so that the beginning (T1) of the traveling direction was 58 ° C. and the end (T2) was 61 ° C. along the taking-up direction of the film. At this time, the running time (heating time) of the film from the beginning (entrance) to the end (exit) of the running direction of the film was about 3 seconds.

After stretching the MD, in order to form a primer layer, the polyurethane aqueous dispersion was coated on one side with a gravure coater so that the coating thickness after stretching was 0.03 to 0.08 μm. Then, TD was stretched. The aqueous dispersion is a melamine resin (DIC's "Beccamin APM") with respect to 100 parts by mass of an anionic water-dispersible polyurethane resin (DIC's "Hydran KU400SF", Tmf = about 0 ° C., Tsf = 80 ° C.). , Tts = 150 ° C.) A water-based coating agent obtained by mixing 7 parts by mass was used.

Next, the stretching of TD was carried out using a tenter as shown in FIG. First, the temperature of the preheating zone 31 (preheating part) was set to 70 ° C., and while preheating was performed, the stretch zone 32 was stretched 3.2 times to TD. At this time, in the stretching zone 32 (stretched portion), a temperature gradient was provided so that the beginning (T1) of the traveling direction was 78 ° C. and the end (T2) was 100 ° C. along the taking-up direction of the film. At this time, the running time (heating time) of the film from the beginning (entrance) to the end (outlet) of the running direction of the film in the stretching zone 32 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) under the conditions of a temperature of 202 ° C. and a relaxation rate of 3%. By continuously producing 1000 m or more in this way, a biaxially stretched polyamide film (rolling amount 2000 m) having a primer layer formed on one side was obtained. The obtained film was wound into a roll.

(2) Preparation of Laminated Body Using the biaxially stretched polyamide film obtained in (1) above, aluminum foil was laminated on the surface of the primer layer using a two-component polyurethane adhesive. A laminate (polyamide film / aluminum foil / sealant film) was produced in the same manner.

Examples 37-75, Comparative Examples 17-36
The composition of the raw materials is changed so that the production conditions and the target thickness of the polyamide film after stretching are changed to those shown in Tables 11 to 14 and the content of the organic lubricant or the inorganic lubricant is as shown in Tables 19 to 22. A polyamide film was obtained in the same manner as in Example 36 except that the ratio was changed. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 36. However, with respect to Example 42, Example 50, Example 58, Example 74 and Example 75, more specifically, the following changes were made.

(1) Example 42 In the laminate obtained in Example 36, a two-component polyurethane adhesive (TM-K55 / CAT manufactured by Toyo Morton Co., Ltd.) was applied to the surface of the polyamide film on which the aluminum foil was not laminated. -10L) was applied so that the coating amount was 5 g / m ^2, and then dried at 80 ° C. for 10 seconds. A PET film (emblet PET-12 manufactured by Unitica, 12 μm in thickness) was laminated on the adhesive-coated surface to prepare a laminate (PET film / polyamide film / aluminum foil / sealant film).

(2) Example 50 In the laminate obtained in Example 43, a two-component polyurethane adhesive (TM-K55 / CAT manufactured by Toyo Morton Co., Ltd.) was applied to the surface of the polyamide film on which the aluminum foil was not laminated. -10L) was applied so that the coating amount was 5 g / m ^2, and then dried at 80 ° C. for 10 seconds. A PET film (emblet PET-12 manufactured by Unitica, 12 μm in thickness) was laminated on the adhesive-coated surface to prepare a laminate (PET film / polyamide film / aluminum foil / sealant film).

(3) Example 58 Using the raw materials shown in Table 1, polyamide resin (polyamide 6 resin) / polyamide resin (polyamide 66 resin 9 / silica-containing polyamide resin / fatty acid-containing polyamide resin = 81.8 / 9.7 / A polyamide-based film was obtained in the same manner as in Example 44, 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. A laminate was produced in the same manner as in Example 36 using the above-mentioned polyamide-based film.

(4) Example 74 The same method as in Example 36 except that an anionic water-dispersible polyurethane resin (“Hydran AP201” manufactured by DIC Corporation) was used as the polyurethane aqueous dispersion for forming the primer layer. A polyamide film was obtained. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 36.

(5) Example 75 The same method as in Example 44 except that an anionic water-dispersible polyurethane resin (“Hydran AP201” manufactured by DIC Corporation) was used as the polyurethane aqueous dispersion for forming the primer layer. A polyamide film was obtained. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 44.

Test Example 2
The physical characteristics of the polyamide films and laminates obtained in Examples 36 to 75 and Comparative Examples 17 to 36 were evaluated. The evaluation results are shown in Tables 15 to 22. The various physical property measurement methods and evaluation methods were carried out in the same manner as in Test Example 1.

As is clear from these results, it can be seen that in the polyamide films of Examples 36 to 75, the A value to the C value are controlled within a predetermined range. The laminates obtained by using these polyamide films had a high Eriksen value and had uniform ductility in all directions when cold-molded. That is, it can be seen that the polyamide films of these examples can exhibit excellent moldability without breaking the aluminum foil, causing delamination, pinholes, and the like.

In particular, since the polyamide films obtained in Examples 36 to 75 have a primer layer containing an anionic water-dispersible polyurethane resin on one side, the laminate using these polyamide films is moisture resistant. It was also excellent in heat.

On the other hand, in Comparative Examples 17 to 36, since the draw ratio of the polyamide film did not satisfy the predetermined range, at least one of the A value to C value of the obtained polyamide film deviated from the predetermined range. Was there. As a result, the laminates obtained by using the polyamide films of these comparative examples cannot have uniform ductility in all directions when cold-molded, and are inferior in moldability. It was confirmed that.

Claims (13)

It is a polyamide film,
(1) The elastic modulus measured in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to a specific direction as 0 degree from an arbitrary point on the film is 1.3 to 3 in each case. It is .5 GPa, and the difference between the maximum value and the minimum value of these elastic moduli is 0.5 GPa or less.
(2) Difference in molding work energy measured in the two directions of 0 degree and 90 degrees [(molding work energy up to 20% elongation in the 0 degree direction)-(up to 20% elongation in the 90 degree direction) Molding work energy)] is 0.02 Nm or less,
A polyamide-based film characterized by this. The polyamide-based film according to claim 1, wherein the dynamic friction coefficient is 0.60 or less. The polyamide-based film according to claim 1, wherein the arithmetic mean roughness Sa is 0.01 to 0.15 μm. With respect to the average thickness in eight directions of 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees clockwise with respect to a specific direction as 0 degrees from an arbitrary point on the film. The polyamide-based film according to claim 1, wherein the standard deviation is 0.200 μm or less. The polyamide-based film according to claim 1, wherein the average thickness is 16 μm or less. The polyamide-based film according to claim 1, which comprises at least one of an organic lubricant and an inorganic lubricant. Furthermore, (3) each of the four directions of 45 degrees, 90 degrees and 135 degrees clockwise with respect to the specific direction from an arbitrary point on the film at the time of 5% elongation by the uniaxial tensile test. The difference between the maximum value and the minimum value of the stress is 35 MPa or less, and (4) the difference between the maximum value and the minimum value of each stress at the time of 15% elongation by the uniaxial tensile test in the above four directions is 40 MPa or less. The polyamide-based film according to claim 1. The laminate containing the polyamide-based film according to claim 1 and the metal foil laminated on the film. A container containing the laminate according to claim 8. This is a method for producing a polyamide film.
(1) A sheet molding step of obtaining an unstretched sheet by molding a melt-kneaded product containing a polyamide resin into a sheet.
(2) A stretching step of obtaining a stretched film by sequentially or simultaneously biaxially stretching the unstretched sheet to MD and TD is included, and
(3) The following formulas a) and b);
a) 0.85 ≤ X / Y ≤ 0.95
b) 8.5 ≤ X x Y ≤ 9.5
(However, X indicates the stretching ratio of the MD, and Y indicates the stretching ratio of the TD.)
Meet both
A method for producing a polyamide-based film. The stretching process is sequential biaxial stretching,
(2-1) The first stretching step of obtaining a first stretched film by stretching the unstretched sheet to MD at a temperature of 50 to 120 ° C. and (2-2) the first stretching step at a temperature of 70 to 150 ° C. The production method according to claim 10, further comprising a second stretching step of obtaining a second stretched film by stretching one stretched film to TD. The production method according to claim 11, wherein the first stretching step is stretching using a roll, and the second stretching step is stretching using a tenter. The production method according to claim 11, wherein the second stretched film is further subjected to a relaxation heat treatment at a temperature of 180 to 230 ° C.

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