JP7086373B2 - Method for manufacturing polyamide-based coated film, laminate and polyamide-based coated film - Google Patents

Description

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

Various resin films are made into various products such as packages by subjecting them to various processes. For example, a vinyl chloride film is used for a package (press-through pack) for a drug (tablet) or the like. Further, for example, a 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 better gas barrier property or moisture resistance 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 types have been the mainstream for exterior materials for lithium-ion batteries, 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 easy to miniaturize. 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 ductility by itself and is inferior in formability. Therefore, by using a polyamide-based film as the resin film constituting the base material layer, ductility is imparted and moldability is enhanced.

The moldability in this case is particularly the moldability 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 not melted and is molded as a solid. There is inter-molding, but in the above applications, formability in cold molding (particularly drawing and overhanging) is required. Cold molding is an advantageous molding method over hot molding in that it is superior in terms of production speed and cost because it does not have a heating process, and it can bring out the original characteristics of the resin. Therefore, as a polyamide-based film, a film suitable for cold molding is being developed.

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 is still a variation (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 the 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 or the like).

In such a stretched polyamide-based 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 a total of four directions (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 vary in the four directions. It becomes difficult to uniformly stretch in all directions during cold molding. 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, or delamination or pinholes to 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 Patent Documents 3 to 10 is high. Is not fully satisfactory. That is, since it is necessary to uniformly stretch in the four directions of vertical, horizontal and diagonal as described above during cold molding, 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 films and their laminates used for cold molding have become 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, although it is desired to develop a polyamide-based film having excellent thickness uniformity and relatively small variation in physical properties in the four directions even if it is thinner, such a film has not been developed yet. The current situation is that there is no such thing.

Further, in the manufacturing process of a lithium ion battery, an electrolytic solution or an acidic substance may spill in the electrolytic solution injection process, and when these adhere to a polyamide-based film, the acid or the electrolytic solution causes a decomposition reaction of the polyamide group to cause the film. Tends to deteriorate. In that case, various mechanical properties such as puncture resistance of the film may be deteriorated, and the film may be torn.

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

The present inventor has been able to achieve 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 repeated diligent 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 coated film and a method for producing the same.

1. 1. A biaxially stretched polyamide-based coat film having a protective layer containing an acid-modified polyolefin resin and a cross-linking agent on at least one side of the surface of the polyamide-based film. The polyamide-based film is a polyamide 6 resin only or a polyamide 6 resin. The protective layer is a film containing the polyamide 66 resin and the polyamide 66 resin, and the protective layer contains 0.1 to 50 parts by mass of a cross-linking agent with respect to 100 parts by mass of the acid-modified polyolefin resin, and simultaneously satisfies the following (1) to (2). A biaxially stretched polyamide-based coated film characterized by being used.
(1) The MD direction is set to 0 degrees from an arbitrary point on the coated film, and each stress at 5% elongation by a uniaxial tensile test is performed in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to that direction. The difference between the maximum value and the minimum value of is 35 MPa or less.
(2) In the above four directions, the difference between the maximum value and the minimum value of each stress at the time of 15% elongation by the uniaxial tensile test is 40 MPa or less.
2. 2. The MD direction is 0 degrees from any point on the coated film, and the standard thickness is 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees clockwise with respect to that direction. Item 2. The biaxially stretched polyamide-based coated film according to Item 1, wherein the deviation is 0.300 μm or less.
3. 3. Item 2. The biaxially stretched polyamide-based coated film according to Item 1 or 2, wherein the average thickness is 18 μm or less.
4. Item 2. The biaxially stretched polyamide-based coat film according to any one of Items 1 to 3, wherein the protective layer containing the acid-modified polyolefin resin has a thickness of 0.01 to 10 μm.
5. Item 2. The biaxially stretched polyamide-based coat film according to any one of Items 1 to 4, wherein the polyamide-based film contains at least one of an organic lubricant and an inorganic lubricant.
6. A laminate containing the biaxially stretched polyamide -based coat film according to any one of Items 1 to 5 and a metal foil.
7. A laminate containing the biaxially stretched polyamide-based coat film according to any one of Items 1 to 5 and a polyester film.
8. A container containing the laminate according to item 6 or 7.
9. Item 6. The method for producing a biaxially stretched polyamide-based coated film according to any one of Items 1 to 5.
(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 step of sequentially biaxially stretching the unstretched sheet to MD and TD, and the sequentially biaxially stretching step is a stretching step (2-1) 50 including the following (2-1) and (2-2). First stretching step (2-2) to obtain a first stretched film by stretching the unstretched sheet to MD using a roll at a temperature of about 120 ° C. The first stretched film at a temperature of 70 to 150 ° C. Includes a second stretching step of obtaining a second stretched film by stretching to TD using a tenter, 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 biaxially stretched polyamide-based coated film.
10. Item 9. The method for producing a biaxially stretched polyamide-based coated film according to Item 9, wherein the second stretched film is further fixed and subjected to a relaxation heat treatment at a temperature of 180 to 230 ° C.

The polyamide-based coated film of the present invention is excellent in thickness uniformity and excellent stress balance during elongation in four directions consisting of 0 degree direction, 45 degree direction, 90 degree direction and 135 degree direction. 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 performing drawing molding (particularly deep drawing molding or overhanging molding) by cold molding. In addition, breakage, delamination, pinholes, etc. of the metal foil are effectively suppressed or prevented, and a highly reliable high-quality product (molded body) can be obtained.

In particular, the polyamide-based coated film of the present invention is excellent in the balance of stress during elongation in the four directions and also in the uniformity of thickness even if the thickness is extremely thin, for example, 18 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, since the polyamide-based coat film of the present invention has a protective layer containing an acid-modified polyolefin resin, the resistance to the electrolytic solution is improved, and when the laminate is formed, it adheres to other base materials. It is also excellent in sex. Further, according to the production method of the present invention, a polyamide-based coated film having the above-mentioned excellent properties can be efficiently and surely produced. In particular, even an extremely thin film having a thickness of 18 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-based coat 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 saw the stretching process by a tenter from the direction a of FIG. It is a figure which shows the direction which measures the stress in a film. It is a figure which shows the sample for measuring the stress in a film. It is a figure which shows the method of measuring the average thickness in a film.

1. 1. Polyamide-based coated film The polyamide-based coated film of the present invention (film of the present invention) has (1) 0 degrees in a specific direction of the coated film, and 45 degrees, 90 degrees, and 135 degrees clockwise with respect to that direction. The difference (A value) between the maximum value and the minimum value of each stress at the time of 5% elongation by the uniaxial tensile test in four directions is 35 MPa or less, and
(2) In the above four directions, the difference (B value) between the maximum value and the minimum value of each stress at the time of 15% elongation by the uniaxial tensile test is 40 MPa or less.
It is characterized by that.

(A) Material and composition of the polyamide film in the present invention
The polyamide-based film in the present invention is a film containing a polyamide resin as a main component. The 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 (methoxylen adipamide) and the like. Further, as the polyamide, for example, 6-nylon / 6,6-nylon, 6-nylon / 6,10-nylon, 6-nylon / 11-nylon, 6-nylon / 12-nylon, etc. It may be united. Further, these may be mixed. Among the above, from the viewpoint of cold moldability, strength, cost and the like, 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 10,000 to 40,000, and 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 deterioration in cold moldability, etc. are further improved. It can be definitely avoided.

The content of the polyamide resin in the polyamide film in the present invention is usually 90 to 100% by mass, preferably 95 to 100% by mass, and more preferably 98 to 100% by mass. That is, a component other than the polyamide resin may be contained, if necessary, as long as the effect of the present invention is 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, it is preferable that at least one of various inorganic lubricants and organic lubricants is contained as the lubricant for imparting slip property. Examples of the method for adding these lubricants (particles) include a method in which particles are contained in a polyamide resin as a raw material and added, a method in which particles are directly added to an extruder, and the like, and one of these methods is used. May be adopted, or two or more methods may be used in combination.

(B) Physical Properties of the Film of the Present Invention The film of the present invention preferably has a biaxially oriented molecular orientation. Such a film can basically be obtained by biaxial stretching. In particular, a biaxially stretched film using a roll and a tenter is suitable.

(B-1) Stress Characteristics The film of the present invention is essential to satisfy the A value and the B value at the same time as an index showing that the stress balance at the time of elongation at the time of secondary processing is very excellent. When the A value and the B value exceed the above ranges, the stress balance in all directions of the polyamide-based film is poor, and it becomes 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 coated film is a metal. (It becomes difficult to follow the foil), so that the metal foil is likely to break, or defects such as delamination and pinholes are likely to occur.

The A 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 A value is not limited, but is usually about 15 MPa.

The B 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 B value is not limited, but is usually about 20 MPa.

The stress in the four directions at the time of 5% elongation is not particularly limited, but is preferably in the range of 35 to 130 MPa, preferably in the range of 40 to 90 MPa in terms of cold formability of the laminate. Is more preferable, and most preferably 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 formability 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, the film of the present invention is humidity-controlled at 23 ° C. × 50% RH for 2 hours, and then, as shown in FIG. 5, an arbitrary position on the film is set as the center point A, and the reference direction (0 degree direction) of the film is arbitrary. The measurement direction is 45 degree direction (b), 90 degree direction (c) and 135 degree direction (d) clockwise from the reference direction (a), and each measurement direction is from the center point A. The sample is cut into strips of 100 mm in length and 15 mm in the direction perpendicular to the measurement direction. For example, as shown in FIG. 5, in the 0 degree direction, a sample 41 (length 100 mm × width 15 mm) is cut in a 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 during 5% and 15% elongation at a tensile speed of 100 mm / min. Measure each. In the above reference direction, when the MD in the stretching step at the time of film production is known, the MD is set as the reference direction.

The film of the present invention satisfying the above-mentioned characteristic values is preferably obtained by a biaxial stretching method including a step of stretching by a tenter in at least one of the vertical direction and the horizontal 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 vertical direction and the horizontal 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-2) Average Thickness and Thickness Accuracy The film of the present invention has a standard deviation of 0.300 or less with respect to the thickness in the four directions as an index showing that the thickness accuracy (thickness uniformity) is very high. It is preferably 0.250 or less, and more preferably 0.200 or less. When the standard deviation indicating the above thickness accuracy is 0.300 or less, the variation in the thickness of the film surface becomes very small. For example, even when the film thickness is 18 μm or less, it is bonded to the metal foil. When the laminate is formed and cold-molded by deep drawing, problems such as delamination and pinholes do not occur, and good moldability can be obtained. When the standard deviation exceeds 0.300, the thickness accuracy is low, so especially when the thickness of the film is small, it is not possible to impart sufficient ductility to the metal foil when it is bonded to the metal foil, and delamination. Alternatively, the occurrence of pinholes becomes remarkable, and good moldability may not be obtained.

In the method for evaluating the thickness accuracy, the polyamide-based coated film is humidity-controlled at 23 ° C. × 50% RH for 2 hours, and then, as shown in FIG. 6, an arbitrary position on the film is set as the center point A and the reference direction (0). After specifying the degree direction), the reference direction (a) from the center point A, the 45 degree direction (b), the 90 degree direction (c), the 135 degree direction (d), and the 180 degree direction clockwise with respect to the reference direction. (E) Draw a total of eight 100 mm straight lines L1 to L8 in each of the eight directions of the 225 degree direction (f), 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) (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 80 points of data obtained by measuring in all the straight lines is calculated, this is used as the average thickness, and the standard deviation of the thickness is calculated using the obtained 80 points of data. .. In the above reference direction, when the MD in the stretching step at the time of film production is known, the MD is set as the reference direction.

In the present invention, the average thickness and the standard deviation may be based on the point A at any one of the polyamide-based films. In particular, in the polyamide-based coated film wound on the obtained film roll, the following It is more desirable that the average thickness and standard deviation within the above range are all three points. The three points are a) a position near the center of the winding width and half the winding amount, b) a position near the right end of the winding width and half the winding amount, and c) a winding width. It is near the left end of and near the end of the winding.

The average thickness of the film of the present invention (the average thickness of the polyamide film and the protective layer containing the acid-modified polyolefin resin combined) is preferably 30 μm or less, more preferably 26 μm or less, and further 18 μm. It is preferably less than or equal to, more preferably 16 μm or less, and most preferably 13 μm or less.

The film of the present invention is preferably a laminate to be bonded to a metal foil, and is suitable for use in cold molding. However, biaxial stretching using a tenter as described later is subject to specific conditions. By performing under satisfactory stretching conditions, even if the film has a small thickness, the stress balance during stretching in the four directions is excellent, and the thickness accuracy (thickness uniformity, etc.) in the four directions is very high. Can be obtained.

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 is likely to be insufficiently imparted to the metal foil when bonded to the metal foil, and the formability is inferior. Therefore, it is usually sufficient to set it to about 2 μm.

The polyamide-based coat film of the present invention is a laminate bonded to a metal foil and is suitable for use in cold molding. However, when the polyamide-based film of the present invention satisfying the above characteristics is used, a metal is used. Sufficient ductility can be imparted to the foil. Due to this effect, moldability is improved during cold molding (among these, drawing molding (especially deep drawing molding)), breakage of the metal leaf can be prevented, and problems such as delamination and pinholes occur. It can be suppressed or prevented.

The smaller the thickness of the polyamide-based coated 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 pressing force at the time of cold molding causes the polyamide film or the metal foil to break significantly. That is, the thinner the film, the larger the variation in stress during elongation tends to be, and the greater the variation in thickness, so 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-based film, the thickness is 15 μm or less, and 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 15 μm or less, the stress balance at the time of elongation in the above four directions is excellent and the thickness is excellent. We have succeeded in providing a polyamide-based film with high uniformity. 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.

(C) Protective Layer Containing Acid-Modified Polyolefin Resin The film of the present invention has a protective layer containing an acid-modified polyolefin resin on at least one side of the surface of the polyamide-based film. That is, it has a protective layer containing an acid-modified polyolefin resin on only one side or both sides of the surface of the polyamide film.
First, the acid-modified polyolefin resin in the present invention will be described. The acid-modified polyolefin resin preferably contains 0.1 to 20% by mass of an acid-modifying component, more preferably 1 to 18% by mass, further preferably 1 to 10% by mass, and particularly preferably 1 to 7% by mass. preferable. If the content of the acid-modifying component is less than 0.1% by mass, sufficient adhesion to the substrate may not be obtained. In addition, it tends to be difficult to make the acid-modified polyolefin resin water-based, such as by dispersing it in an aqueous medium. On the other hand, when it exceeds 20% by mass, the chemical resistance of the coating film tends to decrease.

As the acid denaturing component, an unsaturated carboxylic acid is preferable. Examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid and the like, as well as unsaturated dicarboxylic acid half esters and halfamides. Be done. Among them, acrylic acid, methacrylic acid, maleic acid and maleic anhydride are preferable, and acrylic acid, methacrylic acid and maleic anhydride are particularly preferable from the viewpoint of dispersion stability of the resin.

The olefin component which is the main component of the acid-modified polyolefin resin is not particularly limited, but an alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene and 1-hexene is preferable. .. It may be a mixture of these. Among these, alkene having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene is more preferable, ethylene and propylene are more preferable, and ethylene is most preferable. These may be copolymerized.

The acid-modified polyolefin resin preferably contains a (meth) acrylic acid ester component from the viewpoint of improving the adhesion to the polyamide resin layer. The content of the (meth) acrylic acid ester component is preferably 0.1 to 40% by mass, more preferably 1 to 20% by mass, and even more preferably 3 to 10% by mass. Examples of the (meth) acrylic acid ester component include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms. Among them, (meth) acrylic acid and 1 carbon number of carbon atoms are easy to obtain. Esterates with up to 20 alcohols are preferred. Specific examples of such compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate and the like. A mixture of these may be used. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) butyl acrylate, hexyl acrylate, and octyl acrylate are more preferable, and ethyl acrylate is more preferable from the viewpoint of adhesion to the polyamide resin layer. , Butyl acrylate is more preferred, and ethyl acrylate is particularly preferred. "(Meta) acrylic acid-" means "acrylic acid-or methacrylic acid-".

Each component constituting the acid-modified polyolefin resin may be copolymerized in the acid-modified polyolefin resin, and its form is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

The weight average molecular weight of the acid-modified polyolefin resin is preferably 20,000 to 100,000, more preferably 25,000 to 70,000, further preferably 30,000 to 50,000, and particularly preferably 35,000 to 50,000. When the weight average molecular weight of the acid-modified polyolefin resin is less than 20000, the adhesion to the polyamide resin layer tends to decrease. On the other hand, when the weight average molecular weight exceeds 100,000, it tends to be difficult to obtain a coating composition having excellent dispersibility.

However, in general, the polyolefin resin is sparingly soluble in a solvent, and it may be difficult to measure the molecular weight by a gel permeation chromatograph (GPC) method or the like. In such a case, it is preferable to use the melt flow rate value indicating the fluidity of the molten resin as a guideline for the molecular weight.

The melt flow rate of the acid-modified polyolefin resin (190 ° C., 2.16 kg load according to JIS K7210: 1999) is preferably 0.1 to 1000 g / 10 minutes, preferably 0.1 to 200 g / 10 minutes. Is more preferable, 0.2 to 100 g / 10 minutes is further preferable, and 0.2 to 50 g / 10 minutes is particularly preferable. If it is less than 0.1 g / 10 minutes, it is difficult to produce a resin and it is difficult to make a coating composition. On the other hand, if the amount exceeds 1000 g / 10 minutes, the coating film becomes hard and brittle, so that the adhesion to the substrate tends to decrease.

Specific examples of the acid-modified polyolefin resin include ethylene- (meth) acrylic acid copolymer, ethylene-acrylic acid ester-maleic anhydride ternary copolymer, or ethylene-methacrylic acid ester-maleic anhydride ternary copolymer. Coalescence is most preferred. Acid-modified polyolefin resins include Lexpearl EAA series (Japan Polyethylene), Primacor (Dow Chemical Japan), Nuclel series (Mitsui / DuPont Polychemical), Bondine series (Arkema), Lexpearl ET series. It is commercially available as (Japan Polyethylene), Umex series (Sanyo Kasei), etc. Of these, the Bondine series (Arkema) and the Lexpearl ET series (Japan Polyethylene) are preferable.

The protective layer in the present invention contains an acid-modified polyolefin resin, but more preferably contains polyvinyl alcohol and a cross-linking agent.
As the polyvinyl alcohol, polyvinyl alcohol obtained by completely or partially saponifying a polymer of a vinyl alkyl ester can be used. As the saponification method, a known alkaline saponification method or acid saponification method can be adopted. Above all, a method of alcoholic decomposition using alkali hydroxide in methanol is preferable.

Examples of the vinyl alkyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatic acid and the like. Of these, vinyl acetate is industrially most preferable.

The degree of saponification of polyvinyl alcohol is preferably 80 to 99.9 mol%, more preferably 90 to 99.9 mol%, and further preferably 95 to 99.9 mol% from the viewpoint of electrolytic solution resistance of the protective layer. preferable.

The average degree of polymerization of polyvinyl alcohol is preferably 100 to 3000, more preferably 300 to 3500, and even more preferably 500 to 2000. If it is less than 100, the electrolyte resistance may deteriorate, and if it exceeds 3000, the concentration of the aqueous solution becomes low when used as an aqueous solution described later, and as a result, it tends to be difficult to form a protective layer having a sufficient thickness. be.

As the polyvinyl alcohol, modified polyvinyl alcohol is preferable from the viewpoint of reacting with a cross-linking agent described later and suppressing warpage of the exterior material. The modified polyvinyl alcohol contains components other than the vinyl alkyl ester and vinyl alcohol in the polyvinyl alcohol skeleton, and such components include unsaturated monocarboxylic acids such as crotonic acid, acrylic acid, and methacrylic acid. And their esters, salts, anhydrides, amides, nitriles and; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid and their salts; alkyl vinyl ethers; vinylpyrrolidones, diacetone acrylamide, acetoacetate esters, etc. can give.

Among the modified polyvinyl alcohols, diacetone acrylamide-modified polyvinyl alcohol containing diacetone acrylamide and acetoacetyl-modified polyvinyl alcohol containing acetoacetic ester are preferable from the viewpoint of improving electrolytic solution resistance.

Diacetone acrylamide-modified polyvinyl alcohol can be produced by a known method such as saponifying a diacetone acrylamide-vinyl acetate copolymer. The content of the diacetone acrylamide unit in the diacetone acrylamide-modified polyvinyl alcohol is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 0.5 to 20% by mass.

The acetoacetyl-modified polyvinyl alcohol can be produced by a known method such as a reaction between polyvinyl alcohol and diketene. The content of the acetoacetic ester unit in the acetoacetyl-modified polyvinyl alcohol is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass.

The content of polyvinyl alcohol in the protective layer is preferably 5 to 1000 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin from the viewpoint of improving the electrolytic solution resistance, and the lower limit is preferably 30 parts by mass or more. , 50 parts by mass or more is more preferable, and 100 parts by mass or more is further preferable. The upper limit is preferably 800 parts by mass or less, more preferably 500 parts by mass or less, further preferably 400 parts by mass or less, and particularly preferably 300 parts by mass or less. If it is less than 5 parts by mass, the effect of improving the electrolytic solution resistance tends to be insufficient, while if it exceeds 1000 parts by mass, the electrolytic solution resistance of the edge portion that can be obtained by deep drawing or folding. Tends to decrease.

The cross-linking agent is preferably a compound having two or more functional groups in the molecule capable of reacting with the functional groups of the acid-modified polyolefin resin and / or the modified polyvinyl alcohol. Specifically, polyvalent hydrazide compounds, polyhydric amine compounds, polyvalent oxazoline compounds, polyhydric isocyanate compounds, polyvalent melamine compounds, urea compounds, polyvalent epoxy compounds, polyvalent carbodiimide compounds, polyvalent zirconium salt compounds, etc. can give. These may be contained alone or in a plurality. Among these, a multivalent hydrazide compound, a polyvalent amine compound, and a multivalent oxazoline compound, which are excellent in electrolytic solution resistance and warpage suppressing effect, are preferable, and a polyvalent hydrazide compound is more preferable.

The polyvalent hydrazide compound has two or more hydrazide groups in the molecule and may be a small molecule compound or a polymer, but is a small molecule compound because of its excellent electrolytic solution resistance. Is preferable.

Among the polyhydric hydrazine compounds, the low molecular weight polyhydrazine compound includes, for example, adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutarate dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazine, and maleic acid dihydrazide. Dicarboxylic acid dihydrazine containing 2 to 10 carbon atoms such as fumaric acid dihydrazide and itaconic acid dihydrazide; in particular, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1. , 4-Dihydrazine and the like are aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms, and these may be used alone or in combination of two or more. Among these, adipic acid dihydrazide is preferable because it has an excellent balance between solubility in water, electrolyte resistance, and warpage suppression performance.

The structure and properties of the polyvalent hydrazide polymer (polymer having two or more hydrazide groups in the molecule) among the polyvalent hydrazide compounds are not particularly limited, but for example, acrylamide and acrylate hydrazide are copolymerized. The ones obtained by doing this can be mentioned. The polyvalent amine compound has two or more amine groups in the molecule. It is preferable to have a primary amine or a secondary amine, and more preferably a primary amine. Examples of the polyvalent amine compound include ethylenediamine.

Examples of the multivalent oxazoline compound include a small molecule compound and a polymer having two or more oxazoline groups in the molecule. The higher the polymer, the better the electrolytic solution resistance and the effect of suppressing warpage. It is preferable because it can be obtained.

Among the polyvalent oxazoline compounds, the low molecular weight polyoxazoline compound includes, for example, 2,2'-bis- (2-oxazoline), 2,2'-methylene-bis- (2-oxazoline), 2,2'. -Ethethylene-bis- (2-oxazoline), 2,2'-trimethylen-bis- (2-oxazoline), 2,2'-tetramethylene-bis- (2-oxazoline), 2,2'-hexazoline- Bis- (2-oxazoline), 2,2'-octamethylene-bis- (2-oxazoline), 2,2'-ethylene-bis- (4,4'-dimethyl-2-oxazoline), 2,2' -P-Phenylene-bis- (2-oxazoline), 2,2'-m-phenylene-bis- (2-oxazoline), 2,2'-m-phenylene-bis- (4,4'-dimethyl-2) -Oxazoline), 2,2'-(1,3-phenylene) -bis- (2-oxazoline), bis- (2-oxazolinylcyclohexane) sulfide and bis- (2-oxazolinylnorbornan) sulfide, etc. Examples include low molecular weight compounds. These polyvalent oxazoline compounds may be used alone or in combination of two or more.

Of the polyvalent oxazoline compounds, the polyvalent oxazoline polymer (polymer having two or more oxazoline groups in the molecule) is preferably addition-polymerizable oxazoline as a constituent component thereof, and is monopolymerizable with addition-polymerizable oxazoline. It can be obtained by polymerizing a monomer component that also contains a weight.

The content of the cross-linking agent in the protective layer needs to be 0.1 to 50 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin, and the lower limit is preferably 0.1 part by mass or more, and 0. 2 parts by mass or more is more preferable, 0.5 parts by mass or more is further preferable, and 1 part by mass or more is particularly preferable. As the upper limit, 30 parts by mass or less is preferable, 20 parts by mass or less is more preferable, and 15 parts by mass or less is further preferable. If it is less than 0.1 part by mass, the effect of improving the electrolytic solution resistance and water resistance tends to be insufficient, while if it exceeds 50 parts by mass, there is no performance improvement effect, which is disadvantageous in terms of cost.

Further, in the present invention, as described later, it is preferable to use the acid-modified polyolefin resin as an aqueous dispersion and polyvinyl alcohol as an aqueous solution. Therefore, from the viewpoint of ease of mixing, the cross-linking agent is water-soluble and / or water-dispersed. It is preferably sex-based, and most preferably water-soluble.

The protective layer may contain an acid-modified polyolefin resin, a resin other than polyvinyl alcohol, and other additives as long as the effects of the present invention are not impaired.

Resins other than the acid-modified polyolefin resin and polyvinyl alcohol are not particularly limited, and are, for example, polyvinylidene chloride, vinylidene chloride-polyvinyl chloride copolymer, fluororesin, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, and styrene-malein. Examples thereof include acid resin, poly (meth) acrylonitrile resin, (meth) acrylamide resin, polyester resin, polyamide resin, polyurethane resin, acrylic resin, phenol resin, silicone resin, epoxy resin, and UV curable resin. These may be used alone or in combination of two or more. The content of the resin other than the acid-modified polyolefin and polyvinyl alcohol is not particularly limited as long as the effect is not impaired, but is usually contained in the range of 1 to 500 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin. Is preferable.

The other additives may be appropriately selected depending on the required performance and are not particularly limited, but are, for example, inorganic fine particles composed of magnesium oxide, tin oxide, titanium oxide, calcium carbonate, silica, barium sulfate, calcium silicate, zeolite and the like; Leveling agent, defoaming agent, anti-armpit agent, pigment dispersant, ultraviolet absorber, catalyst, photocatalyst, UV curing agent, wetting agent, penetrant, softening agent, thickener, dispersant, water repellent, lubricant, charging Examples thereof include various chemicals such as inhibitors, antioxidants and vulture accelerators, pigments or dyes, carbon black, carbon nanotubes, glass fibers and the like. These may be used alone or in combination of two or more.

Since it is easy to mix and use an acid-modified polyolefin, a resin other than polyvinyl alcohol, and other additives with an aqueous dispersion of an acid-modified polyolefin resin or an aqueous solution of polyvinyl alcohol, it is water-soluble and / or water-dispersed. It is preferably acidic, and more preferably water-soluble.

The thickness of the protective layer in the present invention is preferably in the range of 0.01 to 10 μm, more preferably 0.1 to 8 μm, more preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm. ..
When the thickness is less than 0.01 μm, the resistance to the electrolytic solution tends to be insufficient, and on the other hand, even if it exceeds 10 μm, no further effect can be obtained and it is disadvantageous in terms of cost.

In the production of the film of the present invention, it is preferable that the protective layer containing the acid-modified polyolefin resin is applied to the polyamide-based film as a liquid substance in which the above-mentioned aqueous dispersion, polyvinyl alcohol, cross-linking agent and the like are mixed.
Above all, providing a liquid substance dissolved or dispersed in an aqueous medium (referred to as an aqueous coating solution) by applying it to a polyamide-based film facilitates processability and inclusion of the above-mentioned other resins and other additives. Preferred from the point of view. The aqueous medium is a liquid containing water as a main component, and may contain a basic compound, an organic solvent, or the like as described later.

In order to obtain the above-mentioned aqueous coating liquid, it is preferable to use an aqueous dispersion as the acid-modified polyolefin resin. The method for producing an aqueous dispersion of the acid-modified polyolefin resin is not particularly limited, but for example, a predetermined amount of the acid-modified polyolefin resin and water is placed in a sealable container equipped with a stirrer, and a basic compound and, if necessary, are added. By heating and stirring in the presence of an organic solvent, the acid-modified polyolefin resin can be stably dispersed in an aqueous medium with a number average particle diameter of 1 μm or less. The solid content concentration of the acid-modified polyolefin resin aqueous dispersion is preferably 50% by mass or less, more preferably 30% by mass or less, in consideration of ease of application, the thickness of the protective layer, and the like. Further, in the aqueous dispersion of the acid-modified polyolefin resin, the content of the emulsifier is preferably 1% by mass or less with respect to the total solid content in order to maintain the water resistance and chemical resistance of the coating film with high performance. , 0.5% by mass is more preferable, and most preferably zero. The presence of emulsifiers in the coating causes them to reduce coating performance.

In the present invention, when producing an aqueous dispersion of an acid-modified polyolefin resin, it is preferable to contain a basic compound and an organic solvent. The basic compound may be any compound capable of neutralizing the carboxyl group. The basic compound may be a metal hydroxide such as LiOH, KOH or NaOH, but a volatile compound is preferable from the viewpoint of water resistance of the coating film, and an organic amine compound such as ammonia, triethylamine or alkanolamine is preferable.

The organic solvent preferably has a solubility in water at 20 ° C. of 10 g / L or more, and for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, tetrahydrofuran, dioxane, acetone, ethylene glycol monoethyl. Examples thereof include ether and ethylene glycol monobutyl ether.

In order to obtain an aqueous coating liquid, it is preferable to use an aqueous solution of polyvinyl alcohol. As a method for producing an aqueous solution of polyvinyl alcohol, a general method, for example, a method of mixing polyvinyl alcohol and water, heating and stirring may be adopted. The solid content concentration of the polyvinyl alcohol aqueous solution may be determined in consideration of ease of application, the thickness of the protective layer, and the like, but is preferably 20% by mass or less from the viewpoint of solubility in water.

In order to obtain an aqueous coating liquid, it is preferable to use a water-soluble and / or water-dispersible cross-linking agent, and an aqueous solution and / or an aqueous dispersion is more preferable.

An aqueous dispersion of an acid-modified polyolefin resin as described above, an aqueous solution of polyvinyl alcohol, an aqueous solution of a cross-linking agent and / or an aqueous dispersion are mixed so as to have the above-mentioned preferable contents to obtain an aqueous coating liquid. Can be done.

Known methods for applying a liquid containing an acid-modified polyolefin resin include gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, and dip coating. A uniform resin layer is brought into close contact with the base material by uniformly applying it to the surface of the base material by a spray coating method or the like, setting it at around room temperature as necessary, and then subjecting it to a drying treatment or a heat treatment for drying. Can be formed.

(D) 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 a film of the present invention and a metal foil laminated on the film (laminated body of the present invention). In this case, the film of the present invention and the metal leaf 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 / the metal foil / the sealant film is laminated in this order is preferable. In this case, the protective layer containing the acid-modified polyolefin resin of the film of the present invention may be arranged on the metal foil side, or the protective layer may be arranged on the surface side of the laminate. Further, an adhesive layer may or may not be interposed between the layers.

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, it is preferable that the laminate of the present invention contains the film of the present invention and the polyester film. In particular, in the present invention, a laminated body in which a polyester film / a film of the present invention / a metal foil / a sealant film is laminated in this order 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, the protective layer containing the acid-modified polyolefin resin in the film of the present invention also functions as an adhesive layer or a primer layer, but an adhesive layer may be interposed between the layers of each layer. In this case, for example. It is preferable to use an adhesive layer such as a urethane adhesive layer or an acrylic adhesive layer between the polyamide film / metal foil and between the metal foil / sealant film.

Since the laminate of the present invention contains the film of the present invention in particular, it can be suitably used for drawing molding (particularly deep drawing molding or overhanging 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.

(E) A 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 manufacturing a container from the laminate of the present invention, and is suitably manufactured by a method for manufacturing 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 at room temperature (usually 50 ° C. or lower, preferably 20 to 30 ° C.) may be adopted without melting the resin contained in the laminate.

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, the molded body by deep drawing molding is preferably used for the exterior body of a lithium ion battery, and the molded body by overhang molding is preferably used for a press-through pack or the like.

2. 2. Method for producing the film of the present invention The method for producing the film of the present invention is as follows.
(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, 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 of polyamide film 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.
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 body, can be obtained.
In this case, the average thickness of the unstretched sheet is not particularly limited, but is generally about 15 to 300 μm, and particularly preferably 50 to 250 μm. By setting within such a range, the stretching step can be carried out more efficiently.

Stretching Step of Polyamide-based Film In the stretching step , a stretched film is obtained by sequentially or simultaneously biaxially stretching the unstretched sheet to MD and TD.
As described above, it is preferably obtained by sequential biaxial stretching including a step of stretching in at least one direction of MD and TD 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 biaxial stretching are simultaneously performed by a tenter by stretching to MD while grasping both ends of the unstretched film and at the same time stretching to TD. 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, a roll having different functions can 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 in the vicinity of the inlet. , Passes through the preheating zone 31, the stretching zone 32 and the fixing and relaxing 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. Then, in the fixing and relaxation heat treatment zone 33, the relaxation heat treatment is performed at a constant temperature. In this way, the second stretched film 14 (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 a tenter is advantageous in terms of productivity, equipment and the like because the MD is stretched by a 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 obtained polyamide-based film has an unbalanced stress in four directions, and it becomes difficult to obtain the film of the present invention.

As for the temperature conditions in the stretching step, for example, it is preferable to stretch in the temperature range of 180 ° C. to 220 ° C. when performing the above-mentioned simultaneous biaxial stretching. 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.). It is preferable to stretch the TD 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, it is preferable to perform fixing and relaxation heat treatment after stretching in both simultaneous biaxial stretching and sequential biaxial stretching using a tenter. The fixing and 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 tenter fixing and relaxation heat treatment zones shown in FIG.
As a means for setting the temperature range at the time of stretching as described above, there are a method of blowing hot air on the film surface, a method of using a far-infrared or near-infrared heater, a method of combining them, and the like. The heating method preferably includes a method of blowing hot air.

<Embodiment in the stretching step>
As the stretching step of the polyamide film in the present invention, a sequential biaxial stretching step of stretching MD with a roll and stretching 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 stress balance during elongation in the four directions and to improve the thickness accuracy in the four directions. Therefore, it is possible to obtain a polyamide-based film having an average thickness of 15 μm or less more reliably and efficiently.

Stretching of MD First, the temperature in stretching MD is preferably stretched in a temperature range of 50 to 70 ° C. using a roll, and more preferably 50 to 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 the extension ratio of the (n + 1) stage to be higher than the extension bridge ratio of the nth stage. This makes it possible to stretch the whole even 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) of the film running direction and the temperature at the end (outlet)) 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 traveling time (heating time) of the film from the beginning (entrance) to the end (exit) of the traveling 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 performed by a tenter in which each zone is formed as shown in FIG. At this time, the temperature of the preheating zone is preferably 60 to 70 ° C. The temperature of the stretching zone 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. ..
Further, it is preferable to raise the temperature sequentially in the stretching zone along the taking-up direction of the film, and the temperature gradient (the temperature T1 at the beginning (inlet) of the traveling direction of the film and the end (outlet)) in the entire stretching zone. The temperature difference from the temperature T2) is usually preferably 5 ° C. or higher, and more preferably 8 ° C. or higher. 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 is preferably 1 to 5 seconds, particularly 2 to 4 seconds. Is more preferable.
In the fixation and relaxation heat treatment zone, it is desirable to perform fixation and 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%.

Formation of protective layer containing acid-modified polyolefin resin
In the above-mentioned production method, it is preferable to apply a liquid substance containing an acid-modified polyolefin resin to the polyamide-based film after stretching to MD. Then, it is preferable to subsequently stretch the film together with the aqueous dispersion to TD under the same stretching conditions as described above (in-line coating). The amount of the aqueous dispersion applied is preferably adjusted so that the thickness of the resin layer formed on the film surface after stretching is 0.01 to 10 μm.
Further, the stretched polyamide film may be coated by a post-coating method (gravure coating method).
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.
The methods for measuring and evaluating various characteristic values of the polyamide-based coated films and laminates obtained in Examples and Comparative Examples were as follows.

(1) Composition of Acid-Modified Polyolefin Resin It was determined by ¹ H-NMR analysis (manufactured by Varian, 300 MHz) at 120 ° C. in ortdichlorobenzene (d ₄ ).
(2) Content of unsaturated carboxylic acid component of acid-modified polyolefin resin The acid value was measured according to JIS K5407, and the content of unsaturated carboxylic acid was determined from the value.

(3) Stress in four directions at 5% elongation and 15% elongation of the polyamide-based coated film The stress in the four directions at 5% elongation and 15% elongation of the polyamide-based coated film is the reference direction (0 degree direction). Was measured and calculated by the method described above.
As the sample film used for the measurement, a polyamide-based coated 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. board.
(4) Average Thickness and Standard Deviation of Polyamide-based Coated Film The average thickness and standard deviation of the polyamide-based coated 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 coated 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 referred to as "A", and b) the winding. The one collected near the right end of the width and at a position corresponding to half of the winding amount is referred to as "B", and c) the one collected near the left end of the winding width and near the end of the winding. Was written as "C".

(5) Thickness of Protective Layer Containing Acid-Modified Polyolefin Resin The obtained polyamide-based coat 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 vapor-phase stained with _RuO4 solution for 1 hour, and the protective layer thickness was measured at an acceleration voltage of 100 kV by permeation measurement using JEM-1230 TEM (manufactured by JEOL Ltd.). At this time, five arbitrary points for measuring the thickness of the protective layer were selected, and the average value of the measured values at the five points was taken as the thickness.
As the sample film used for the measurement, a polyamide-based coated 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. board.
(6) Formability of laminated body Drawing depth (Eriksen test)
Based on JISZ2247, a steel ball punch was pressed against the obtained laminate at a predetermined pushing depth using an Eriksen testing machine (No. 5755 manufactured by Yasuda Seiki Seisakusho Co., Ltd.), and the Eriksen value was obtained. 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 measurement environment was 23 ° C. × 50% RH.

(7) Electrolyte-resistant liquid of the film of the present invention An electrolytic solution (ethylene carbonate / ethylmethyl carbonate / diethyl carbonate (1/1/1 (1/1 / 1)) was placed on the surface of the protective layer containing the acid-modified polyolefin resin formed on the polyamide-based film. A solution containing LiPF ₆ in a mixed solution of volume ratio)): 10 ml of LBG-00093) manufactured by Kishida Chemical Co., Ltd. was added dropwise and coated with a watch glass. Three types of samples were prepared, which were left at room temperature (23 ° C.) for a predetermined time of 6 hours, 12 hours, and 24 hours. In each sample, the electrolytic solution on the resin layer was wiped off with gauze, and the surface condition of the polyamide film was visually observed. Depending on the presence or absence of holes generated by the electrolytic solution on the surface of the polyamide-based film and the state of whitening, evaluation was made on a three-point scale of ◯ (no change), Δ, (partially whitening), and × (total whitening or holes).
In Comparative Example 18, the electrolytic solution was dropped on the surface of the primer layer, and in Examples 42 and 43, the electrolytic solution was dropped on the surface where the protective layer containing the acid-modified polyolefin resin was 0.3 μm.

Reference example 1
<Manufacturing of aqueous dispersion "E-1">
3. Using a stirrer equipped with a hermetically sealed 1 L glass container with a heater, 60.0 g of Bondine TX-8030 (manufactured by Alchema) as an acid-modified polyolefin resin, 48.0 g of isopropanol, and 3 as a basic compound. When 9 g of N, N-dimethylethanolamine and 188.1 g of distilled water were charged in a glass container and stirred at a stirring blade rotation speed of 300 rpm, no resin sedimentation was observed at the bottom of the container, and the container was in a floating state. It was confirmed that it was. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the temperature inside the system was maintained at 140 ° C., and the mixture was further stirred for 60 minutes. After that, it is cooled to room temperature (about 25 ° C) while stirring at a rotation speed of 300 rpm by air cooling, and the liquid component in the flask is pressurized filtered with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) (wire diameter 0.035 mm, plain weave). Air pressure was 0.2 MPa) to obtain a milky white uniform aqueous dispersion "E-1".

Reference Example 2 <Manufacturing of aqueous dispersion "E-2">
Using a stirrer equipped with a sealed glass container with a pressure resistance of 1 L with a heater, 60.0 g of Primacol 5980I (manufactured by Dow Chemical Co., Ltd.) as an acid-modified polyolefin resin, 17.7 g of triethylamine as a basic compound, and When 222.3 g of distilled water was charged in a glass container and the stirring blade was stirred at a rotation speed of 300 rpm, no precipitation of resin granules was observed at the bottom of the container, and it was confirmed that the container was in a floating state. .. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the temperature inside the system was maintained at 120 ° C., and the mixture was further stirred for 30 minutes. Then, after cooling to room temperature (about 25 ° C.) with air cooling while stirring at a rotation speed of 300 rpm, pressure filtration is performed with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) at an air pressure of 0.2 MPa. Then, a slightly cloudy aqueous dispersion "E-2" was obtained.

Reference example 3
<Manufacturing of aqueous dispersion "E-3">
The acid-modified polyolefin resin "P-1" was produced as follows.
280 g of a propylene-butene-ethylene ternary copolymer (Huls Japan, Bestplast 708, propylene / butene / ethylene = 64.8 / 23.9 / 11.3% by mass) in a four-necked flask. , Heat-melted in a nitrogen atmosphere. Then, while keeping the temperature in the system at 170 ° C., 32.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour under stirring, and then each was added. It was allowed to react for 1 hour. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin. This resin was further washed with acetone several times to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum drier to obtain an acid-modified polyolefin resin "P-1".
Using the obtained acid-modified polyolefin resin "P-1", 60.0 g of acid-modified polyolefin resin (P-1) and 90.0 g of n-propanol (manufactured by Wako Pure Chemical Industries, Ltd., special grade, boiling point 97 ° C.) , 6.2 g of triethylamine (manufactured by Wako Pure Chemical Industries, Ltd., special grade, boiling point 89 ° C.) and 143.8 g of distilled water were charged in a glass container, and the stirring blade was stirred at a rotation speed of 300 rpm. No sedimentation was observed, and it was confirmed that the resin was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the temperature inside the system was maintained at 140 ° C., and the mixture was further stirred for 60 minutes. After that, it was cooled to room temperature (about 25 ° C.) by air cooling while stirring at a rotation speed of 300 rpm, and then pressurized filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave). Then, a milky white-yellow uniform aqueous dispersion "E-3" was obtained.

Reference example 4
<Manufacturing of aqueous dispersion "E-4">
In a sealable 1 liter glass container equipped with a stirrer and a heater, 120.0 g of Yumex 1010 (manufactured by Sanyo Kasei Co., Ltd.) as a polyolefin resin, 12.6 g of N, N-dimethylethanolamine as a basic compound, and organic 120 g of the solvent isopropanol and 347.4 g of distilled water were charged, sealed, and then heated to 160 ° C. (internal temperature) with stirring blades at 300 rpm. After holding at 160 ° C. for 1 hour under stirring, the heater was turned off and naturally cooled to room temperature under stirring to obtain a slightly yellow and translucent uniform dispersion (solid content concentration: 20% by mass). After cooling, the liquid component in the flask is pressure-filtered (pneumatic pressure 0.2 MPa) with a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform aqueous dispersion "E-4". rice field.

Reference example 5
<Manufacturing of aqueous dispersion "E-5">
A pressure resistant autoclave with an internal volume of 1000 L equipped with a stirring blade, using 100 kg of Bondine LX4110 (manufactured by Arkema) as a polyolefin resin, 150 kg of N-propanol, 4.5 kg of triethylamine (TEA) and 245.5 kg of distilled water. Was charged, and after sealing, the stirring blade was stirred at a rotation speed of 40 rpm. Next, the temperature inside the autoclave was heated to 120 ° C., and the mixture was further stirred for 120 minutes while maintaining 120 ° C. Then, it was cooled to about 40 ° C. by air cooling while stirring at a rotation speed of 40 rpm, and then filtered through a 300 mesh stainless steel filter to obtain an aqueous dispersion of a polyolefin resin. No undispersed matter was confirmed on the 300 mesh filter after filtration.

Table 1 shows the compositions of the acid-modified polyolefin resins used in the production of the acid-modified polyolefin resin aqueous dispersions "E-1" to "E-5".

Reference example 6
<Manufacturing of water-based coating liquid "F-1">
As polyvinyl alcohol, polyvinyl alcohol having a saponification degree of 98.5 mol% and an average degree of polymerization of 1700 (hereinafter referred to as unmodified PVA) was used and dissolved in water so that the solid content concentration was 10% by mass. An aqueous polyvinyl alcohol solution (hereinafter referred to as a non-denatured PVA aqueous solution) was prepared.
E-5 is used as the aqueous dispersion of the acid-modified polyolefin resin, a non-denatured PVA aqueous solution, and a polyvalent oxazoline polymer as a cross-linking agent (Epocross WS700 manufactured by Nippon Catalyst Co., Ltd., solid content concentration 25% by mass, hereinafter referred to as WS700). Was mixed so that the solid content of the unmodified PVA was 100 parts by mass and the solid content of the cross-linking agent was 5 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin solid content. Got

Reference example 7
<Manufacturing of water-based coating liquid "F-2">
An aqueous coating liquid was obtained in the same manner as in Reference Example 6 except that the unmodified PVA solid content was mixed so as to be 300 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin solid content.

Reference example 8
<Manufacturing of water-based coating liquid "F-3">
As polyvinyl alcohol, diacetone acrylamide-modified polyvinyl alcohol (hereinafter referred to as modified PVA) having a diacetone acrylamide unit content of 12% by mass, a saponification degree of 98.5 mol%, and an average degree of polymerization of 1700 is used to obtain a solid content concentration. Was dissolved in water so as to be 10% by mass to prepare a polyvinyl alcohol aqueous solution (hereinafter referred to as a modified PVA aqueous solution).
As a cross-linking agent, an aqueous solution of a hydrazide compound (manufactured by Otsuka Chemical Co., Ltd., adipic acid dihydrazide) (hereinafter referred to as ADH) is used and mixed with water so that the solid content concentration becomes 5% by mass, and contains the cross-linking agent. An aqueous solution (hereinafter referred to as ADH aqueous solution) was prepared.
E-5 was used as the aqueous dispersion of the acid-modified polyolefin resin, and the modified PVA aqueous solution and the ADH aqueous solution were used as the cross-linking agent. The modified PVA solid content was 100 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin solid content. After mixing so that the solid content of the cross-linking agent was 5 parts by mass, the mixture was stirred at room temperature to obtain an aqueous coating liquid.

Reference example 9
<Manufacturing of water-based coating liquid "F-4">
An aqueous coating liquid was obtained in the same manner as in Reference Example 8 except that the modified PVA solid content was mixed with 100 parts by mass of the acid-modified polyolefin resin solid content so as to be 300 parts by mass.

Reference example 10
<Manufacturing of water-based coating liquid "F-5">
An aqueous coating liquid was obtained in the same manner as in Reference Example 6 except that it did not contain an acid-modified polyolefin resin and was mixed so that the solid content of WS700 was 5 parts by mass with respect to 100 parts by mass of the unmodified PVA solid content. rice field.

Reference example 11
<Manufacturing of water-based coating liquid "F-6">
An aqueous coating liquid was obtained in the same manner as in Reference Example 8 except that it did not contain an acid-modified polyolefin resin and was mixed so that the solid content of the cross-linking agent was 5 parts by mass with respect to 100 parts by mass of the modified PVA solid content. ..

Example 1
(1) Manufacture of polyamide-based coated film A1030BRF / silica using Unitika's polyamide 6 resin (A1030BRF, relative viscosity 3.1) and nylon 6 resin containing 6% by mass of silica (A1030QW, relative viscosity 2.7) as raw materials. Nylon 6 resin contained = 97.5 / 2.5 (mass ratio) was melt-kneaded in an extruder, supplied to a T-die, and discharged into a sheet. The unstretched sheet was manufactured 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 12 μm.
Next, the obtained unstretched sheet was subjected to a stretching step by sequentially biaxial stretching. More specifically, 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 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.
After stretching the MD, a gravure coater was used to form a protective layer containing the acid-modified polyolefin resin, and the aqueous dispersion "E-1" obtained in Reference Example 1 was stretched to have a resin layer thickness of 0.5 μm. It was coated on one side so as to be. Then, TD was stretched.

Next, the stretching of TD was carried out using a tenter as shown in FIG. First, the temperature of the preheating zone (preheating portion) was set to 65 ° C., and the stretching zone was stretched 3.2 times to TD while preheating. At this time, in the stretching zone (stretched portion), a temperature gradient was provided along the film taking-up direction so that the beginning (T1) of the traveling direction was 74 ° C. and the end (T2) was 96 ° C. 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 in the stretching zone was about 3 seconds.
The film that passed through the stretching zone was fixed and relaxed heat-treated in the fixing and relaxing heat treatment zone (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 protective layer containing an acid-modified polyolefin resin 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, a two-component polyurethane adhesive was used on the surface of the film on which the protective layer containing the acid-modified polyolefin resin was not formed. (“TM-K55 / CAT-10L” manufactured by Toyo Morton Co., Ltd.) was applied so that the coating amount was 5 g / m ² , and then 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 Kagaku Tohcello Co., Ltd.)) was applied to the coated surface. )) Were laminated and aged for 72 hours in an atmosphere of 40 ° C. to prepare a laminate (polypropylene-based coat film / aluminum foil / sealant film).

Examples 2-35, Comparative Examples 1-16
A polyamide-based coated film was obtained by the same method as in Example 1 except that the production conditions and the target thickness of the polyamide-based film after stretching were changed to those shown in Table 2. Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1. However, with respect to Example 22, Example 34, and Example 35, more specifically, the following changes were made.

(1) Example 22 In the production of the polyamide-based film shown in Example 1, a polyamide 6 resin (A1030BRF) manufactured by Unitika, a polyamide 66 resin (A226) manufactured by Unitica, and a nylon 6 resin containing 6% by mass of silica (A1030QW). ) Is a composition of A1030BRF / A226 / silica-containing nylon 6 resin = 89.0 / 9.7 / 1.3 (mass ratio) as a raw material, and the production conditions are changed to those shown in Table 2. A polyamide-based coated film was obtained in the same manner as in Example 1 except for the above. Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.
(2) Example 34 In the laminate obtained in Example 1, a two-component polyurethane adhesive (TM-K55 / CAT manufactured by Toyo Morton Co., Ltd.) was placed on the surface of the polyamide film on which the aluminum foil was not laminated. -10 L) 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 Unitika Ltd., thickness 12 μm) was bonded to the adhesive-coated surface to prepare a laminate (PET film / polyamide film / aluminum foil / sealant film).
(3) Example 35 In the laminate obtained in Example 7, a two-component polyurethane adhesive (TM-K55 / CAT manufactured by Toyo Morton Co., Ltd.) was placed on the surface of the polyamide film on which the aluminum foil was not laminated. -10 L) 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 Unitika Ltd., thickness 12 μm) was bonded to the adhesive-coated surface to prepare a laminate (PET film / polyamide film / aluminum foil / sealant film).

Examples 36, 38, 40
In order to form the protective layer containing the acid-modified polyolefin resin, the aqueous dispersions "E-2", "E-3" and "E-4" obtained in Reference Examples 2, 3 and 4 were used ( A polyamide-based coated film was obtained in the same manner as in Example 1 except (see Table 1). Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Examples 37, 39, 41
In order to form the protective layer containing the acid-modified polyolefin resin, the aqueous dispersions "E-2", "E-3" and "E-4" obtained in Reference Examples 2, 3 and 4 were used ( A polyamide-based coated film was obtained in the same manner as in Example 13 except (see Table 1). Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Example 42
A water-based dispersion "E-1" was used on the surface of the film of the polyamide-based coat film obtained in Example 1 on which the protective layer containing the acid-modified polyolefin resin was not formed, and gravure coating (test coater manufactured by HIRANO TECSEED Co., Ltd.) was used. The resin layer was coated so that the thickness of the resin layer after drying was 0.5 μm by the microgravia coating method).
Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Example 43
A water-based dispersion "E-1" was used on the surface of the film of the polyamide-based coat film obtained in Example 7 on which the protective layer containing the acid-modified polyolefin resin was not formed, and gravure coating was performed (test coater manufactured by HIRANO TECSEED Co., Ltd.). The resin layer was coated so that the thickness of the resin layer after drying was 1.0 μm by the microgravia coating method).
Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Examples 44, 45
A polyamide-based coated film was obtained in the same manner as in Example 1 except that the thickness of the protective layer containing the acid-modified polyolefin resin on the film surface was changed to be as shown in Table 2. Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Examples 46, 48, 50, 52
The same as in Example 1 except that the aqueous coating liquids "F-1" to "F-4" obtained in Reference Examples 6 to 9 were used to form the protective layer containing the acid-modified polyolefin resin. A polyamide-based coated film was obtained by the method. Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Examples 47, 49, 51, 53, Comparative Examples 19, 20
The same as in Example 13 except that the aqueous coating liquids "F-1" to "F-6" obtained in Reference Examples 6 to 9 were used to form the protective layer containing the acid-modified polyolefin resin. A polyamide-based coated film was obtained by the method. Using the obtained polyamide-based coated film, a laminate was produced in the same manner as in Example 1.

Comparative Example 17
In the production of the polyamide-based coated film of Example 1, a polyamide-based film was obtained by the same method as in Example 1 except that the protective layer containing the acid-modified polyolefin resin was not formed after the MD was stretched. Using the obtained polyamide film, a laminate was produced in the same manner as in Example 1.

Comparative Example 18
In the production of the polyamide-based coated film of Example 7, after stretching the MD, a polyurethane aqueous dispersion was coated on one side with a gravure coater so that the coated thickness after stretching was 0.05 μm in order to form a primer layer. Then, TD was stretched. The aqueous dispersion is a tri (methoxymethyl) melamine resin (DIC) with respect to 100 parts by mass of an anionic water-dispersible polyurethane resin (“Hydran KU400SF” manufactured by DIC, Tmf = about 0 ° C., Tsf = 80 ° C.). A water-based coating agent obtained by mixing 7 parts by mass of "Beccamin APM" manufactured by Tts = 150 ° C.) was used.
After stretching the TD, a polyamide film was obtained in the same manner as in Example 7. Using the obtained polyamide film, an aluminum foil was laminated on the surface of the primer layer using a two-component polyurethane adhesive, and the laminate (polyamide film / aluminum foil / sealant film) was the same as in Example 1. ) Was produced.

Table 2 shows the production conditions of the polyamide-based coated film in Examples 1 to 53 and Comparative Examples 1 to 20, the characteristic values and the evaluation results of the obtained polyamide-based coated film and the laminate.

なお、表２において、各延伸倍率は１を基準とした倍率（倍）を示す。また、各熱処理温度の単位は「℃」、弛緩率の単位は「％」、目標厚みは「μｍ」を示す。

In addition, in Table 2, each draw ratio shows the magnification (times) with respect to 1. The unit of each heat treatment temperature is "° C", the unit of relaxation rate is "%", and the target thickness is "μm".

In Examples 1 to 53, since the draw ratio of the polyamide-based coated film was in a predetermined range, the obtained polyamide-based coated film was found in the 0-degree direction, the 45-degree direction, the 90-degree direction, and the 135-degree direction in the uniaxial tensile test. The difference between the maximum value and the minimum value of the stress at the time of 5% elongation in the direction was 35 MPa or less, and the difference between the maximum value and the minimum value of the stress at the time of 15% elongation was 40 MPa or less. The laminate obtained by using these polyamide films had a high Eriksen value and had uniform ductility in all directions when cold-molded. That is, the polyamide films of these examples had excellent moldability without breaking the aluminum foil, causing delamination, pinholes, and the like.
Further, the polyamide-based coated films obtained in Examples 1 to 53 have a protective layer containing an acid-modified polyolefin resin on at least one side, and the laminate using these polyamide-based coated films is a polyamide-based coated film. Since the protective layer containing the acid-modified polyolefin resin layer is the outermost layer, it has excellent electrolytic solution resistance.

On the other hand, in Comparative Examples 1 to 16, since the draw ratio of the polyamide film did not satisfy a predetermined range, the obtained polyamide film was obtained in the uniaxial tensile test in the 0 degree direction, the 45 degree direction, and the 90 degree direction. The difference between the maximum and minimum values of stress at 5% elongation in the direction and 135 degree direction was 35 MPa or less, and the difference between the maximum and minimum values of stress at 15% elongation did not satisfy 40 MPa or less. .. Therefore, the laminate obtained by using the polyamide films of these comparative examples has a low Eriksen value, cannot be made to have uniform ductility in all directions when cold-molded, and has moldability. It was inferior to.
Further, since the polyamide films of Comparative Examples 17 to 20 did not have a protective layer containing an acid-modified polyolefin resin, the obtained laminate was inferior in electrolytic solution resistance.

Claims (10)

A biaxially stretched polyamide-based coat film having a protective layer containing an acid-modified polyolefin resin and a cross-linking agent on at least one side of the surface of the polyamide-based film. The polyamide-based film is a polyamide 6 resin only or a polyamide 6 resin. The protective layer is a film containing the polyamide 66 resin and the polyamide 66 resin, and the protective layer contains 0.1 to 50 parts by mass of a cross-linking agent with respect to 100 parts by mass of the acid-modified polyolefin resin, and simultaneously satisfies the following (1) to (2). A biaxially stretched polyamide-based coated film characterized by being used.
(1) The MD direction is set to 0 degrees from an arbitrary point on the coated film, and each stress at 5% elongation by a uniaxial tensile test is performed in four directions of 45 degrees, 90 degrees, and 135 degrees clockwise with respect to that direction. The difference between the maximum value and the minimum value of is 35 MPa or less.
(2) In the above four directions, the difference between the maximum value and the minimum value of each stress at the time of 15% elongation by the uniaxial tensile test is 40 MPa or less. The MD direction is 0 degrees from any point on the coated film, and the standard thickness is 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees clockwise with respect to that direction. The biaxially stretched polyamide-based coated film according to claim 1, wherein the deviation is 0.300 μm or less. The biaxially stretched polyamide-based coated film according to claim 1 or 2, wherein the average thickness is 18 μm or less. The biaxially stretched polyamide-based coat film according to any one of claims 1 to 3, wherein the protective layer containing the acid-modified polyolefin resin has a thickness of 0.01 to 10 μm. The biaxially stretched polyamide-based coat film according to any one of claims 1 to 4, wherein the polyamide-based film contains at least one of an organic lubricant and an inorganic lubricant. A laminate containing the biaxially stretched polyamide -based coat film according to any one of claims 1 to 5 and a metal foil. A laminate containing the biaxially stretched polyamide-based coat film according to any one of claims 1 to 5 and a polyester film. A container containing the laminate according to claim 6 or 7. The method for producing a biaxially stretched polyamide-based coated film according to any one of claims 1 to 5.
(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 step of sequentially biaxially stretching the unstretched sheet to MD and TD, and the sequentially biaxially stretching step is a stretching step (2-1) 50 including the following (2-1) and (2-2). First stretching step (2-2) to obtain a first stretched film by stretching the unstretched sheet to MD using a roll at a temperature of about 120 ° C. The first stretched film at a temperature of 70 to 150 ° C. Includes a second stretching step of obtaining a second stretched film by stretching to TD using a tenter, 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 biaxially stretched polyamide-based coated film. The method for producing a biaxially stretched polyamide-based coated film according to claim 9, wherein the second stretched film is further fixed and subjected to a relaxation heat treatment at a temperature of 180 to 230 ° C.

Images