JP2015051525A - Biaxially stretched nylon film, laminated film, laminated packaging material, battery, and method for producing biaxially stretched nylon film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a biaxially stretched nylon film having excellent deep drawing molding property at cold molding, a laminated film, a laminated packaging material and a method for producing a biaxially stretched nylon film.SOLUTION: There is provided a biaxially stretched nylon film using a nylon resin as a raw material, wherein when, among the three-dimensional refractive indices of the film, the maximum refractive index in the plane of the film is defined as Nx, the minimum refractive index in the plane of the film is defined as Ny and the refractive index value in the thickness direction of the film is defined as Nz, a plane orientation degree (P) satisfies the conditions expressed by the following mathematical formula (F1), the dynamic friction coefficient μdbetween films in the film is 0.45 or less and the dynamic friction coefficient μdbetween a take-up roll of the film and the film is 0.3 or less. P=(Nx+Ny)/2-Nz≥0.042 (F1).

Description

  The present invention relates to a biaxially stretched nylon film, a laminate film, a laminate packaging material, a battery, and a method for producing a biaxially stretched nylon film.

Biaxially stretched nylon film (hereinafter also referred to as ONy film) is excellent in strength, impact resistance, pinhole resistance, etc., and is therefore often used for applications that require heavy strength loads such as heavy weight packaging and water packaging. .
The laminate packaging material including the ONy film is used as a packaging material for cold molding that is superior in safety and flexibility in shape (drawing moldability) and can be reduced in thickness and weight compared to hot molding. (For example, Patent Document 1). A laminate packaging material including such an ONy film can be suitably used for battery packaging or pharmaceutical packaging.

JP 2008-44209 A

  On the other hand, the packaging material for cold molding is required to further improve the drawability (deep drawability) as the capacity of batteries and the like increases. However, in a laminate packaging material including a biaxially stretched nylon film as described in Patent Document 1, there is no problem in ordinary drawing, but there is a possibility that pinholes may occur when deep drawing is performed. .

  Therefore, an object of the present invention is to provide a biaxially stretched nylon film, a laminate film, a laminate packaging material, a battery, and a method for producing a biaxially stretched nylon film having excellent deep drawability during cold forming.

As a result of intensive studies to solve the above problems, the present inventors have found that there is a correlation between the molecular orientation and slipperiness of the film and the deep drawability, and have completed the present invention. .
In the present invention, cold molding refers to molding performed at room temperature without heating. As one means of such cold forming, for example, using a cold forming machine used for forming aluminum foil or the like, a sheet material is pushed into a female mold with a male mold and pressed at a high speed. According to such cold forming, plastic deformation such as molding, bending, shearing and drawing can be generated without heating.

The biaxially stretched nylon film of the present invention is a biaxially stretched nylon film made from a nylon resin, and among the three-dimensional refractive indexes of the film, the maximum refractive index value in the film plane is Nx, and the film When the in-plane minimum refractive index value is Ny and the refractive index value in the thickness direction of the film is Nz, the degree of plane orientation (P) satisfies the condition represented by the following formula (F1), and The dynamic friction coefficient μd ₁ between the films in the film is 0.45 or less, and the dynamic friction coefficient μd ₂ between the winding roll of the film and the film is 0.3 or less.
P = (Nx + Ny) /2−Nz≧0.042 (F1)

As shown in the above formula (F1), the difference between the degree of plane orientation (P), that is, the intermediate value between the maximum refractive index value and the minimum refractive index value in the film plane, and the refractive index value in the film thickness direction is In the case where the above conditions are satisfied, the degree of stretching of the biaxially stretched nylon film is in a range suitable for cold forming, and the present inventors can obtain a biaxially stretched nylon film having excellent deep drawability during cold forming. Guess.
In addition, when the dynamic friction coefficients μd ₁ and μd ₂ of the film satisfy the above conditions, since the film surface is not too slippery and friction suitable for molding is imparted to the film surface during cold molding, The present inventors infer that moderate plastic deformation can be caused during molding.

Furthermore, in the biaxially stretched nylon film of the present invention, it is preferable that the plane refractive index ratio (Nx / Ny) of the film satisfies the condition represented by the following mathematical formula (F2).
1.0 ≤ (Nx / Ny) ≤ 1.0065 (F2)

On the other hand, the laminate film of the present invention is formed by laminating the biaxially stretched nylon film of the present invention.
The laminate film of the present invention is preferably used for cold forming.
Although the use of the laminate film of the present invention is not particularly limited, for example, it can be suitably used for a battery exterior material or a PTP packaging material.
When the laminate film of the present invention is used as a battery exterior material, the lamination mode of the laminate film is not particularly limited. For example, the biaxially stretched nylon film / aluminum layer / polypropylene layer and the polyethylene terephthalate layer / biaxial Examples include stretched nylon film / aluminum layer / polypropylene layer.
In the laminate film of the present invention, when used for a PTP packaging material, the lamination mode of the laminate film is not particularly limited, and examples thereof include the biaxially stretched nylon film / aluminum layer / polyvinyl chloride layer.

  Furthermore, in the laminate film of the present invention, the surface layer is preferably the biaxially stretched nylon film.

The laminate packaging material of the present invention is characterized by using the laminate film of the present invention.
The battery of the present invention is characterized in that the laminate film is used as an exterior material.

  On the other hand, the method for producing a biaxially stretched nylon film for producing the biaxially stretched nylon film of the present invention includes a raw film production process for forming a raw film from the raw material, and a tubular biaxial stretch method. It comprises a biaxial stretching step of biaxially stretching the raw film, and a heat setting step of heat-setting the film after the biaxial stretching step by performing a heat treatment.

Furthermore, in the method for producing a biaxially stretched nylon film of the present invention, the biaxial stretching step has a stretching ratio of 2 in the MD direction (moving direction of the film) and in the TD direction (direction width perpendicular to the moving direction of the film). It is preferable that the raw film is biaxially stretched under a condition that the stretching ratio in the TD direction is 0.1 times or more larger than the stretching ratio in the MD direction.
Moreover, in the manufacturing method of the biaxially stretched nylon film of this invention, it is preferable that the heat processing temperature of the said film in the said heat setting process is 190 degreeC or more and 215 degrees C or less.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the biaxially-stretched nylon film, laminate film, laminate packaging material, battery, and biaxially-stretched nylon film which have the deep drawing moldability excellent at the time of cold forming can be provided.

It is a schematic block diagram which shows an example of the apparatus which manufactures the biaxially stretched nylon film of this invention.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.
[Configuration of biaxially stretched nylon film]
The biaxially stretched nylon film (ONy film) of this embodiment is formed by biaxially stretching a raw film made of nylon resin as a raw material and heat-fixing it at a predetermined temperature.
Nylon 6, nylon 8, nylon 11, nylon 12, nylon 6,6, nylon 6,10, nylon 6,12, etc. can be used as the nylon resin as the raw material. Nylon 6 (hereinafter also referred to as Ny6) is preferably used from the viewpoint of physical properties, melting characteristics, and ease of handling.
Here, the chemical formula of Ny6 is shown in the following formula (1).

  The number average molecular weight of the raw material nylon resin is preferably 15000 or more and 30000 or less, and more preferably 22000 or more and 24000 or less.

  Moreover, it is preferable to add a silica fine powder in a raw material. The content of the silica fine powder is preferably 300 to 2500 ppm by mass, more preferably 500 to 2000 ppm by mass. When the silica fine powder is less than 300 ppm by mass, the inner surface side of the tube constituting the raw fabric film becomes too smooth, and there is a possibility that the winding of the film after stretching is deteriorated. Furthermore, when the stretched film is printed / laminated (secondary processing), the slipping property is deteriorated, which may cause wrinkles. On the other hand, when the silica fine powder exceeds 2500 ppm by mass, the amount of generated scum increases when the raw material is melt-extruded, and the continuous productivity may be lowered because it is necessary to increase the frequency of cleaning the die of the extruder.

In this embodiment, among the three-dimensional refractive indexes of the ONy film, the maximum refractive index value in the ONy film surface is Nx, the minimum refractive index value in the ONy film surface is Ny, and the refractive index in the thickness direction of the ONy film is When the value is Nz, the degree of plane orientation (P) satisfies the condition represented by the following mathematical formula (F1), and the dynamic friction coefficient μd ₁ between the films in the ONy film is 0.45 or less, and the ONy film The dynamic friction coefficient μd ₂ between the take-up roll and the ONy film must be 0.3 or less.
P = (Nx + Ny) /2−Nz≧0.042 (F1)

When the degree of plane orientation (P) is less than 0.042, the deep drawability of the resulting film becomes insufficient, and the strength decreases.
In the present embodiment, it is preferable that the planar refractive index ratio (Nx / Ny) of the ONy film satisfies the condition represented by the following mathematical formula (F2).
1.0 ≤ (Nx / Ny) ≤ 1.0065 (F2)
When the plane refractive index ratio (Nx / Ny) is outside the above range, the in-plane balance of the resulting film is lost, so that the deep drawability and strength tend to decrease. Further, from the viewpoint of obtaining excellent deep drawability during cold forming, the plane refractive index ratio (Nx / Ny) is more preferably 1.0055 or less.
Here, each component Nx, Ny, and Nz of the three-dimensional refractive index was obtained by measuring the refractive index of the film tilted by 0 ° and 45 ° using RETS-100 manufactured by Otsuka Electronics Co., Ltd. It can be calculated by analyzing the results. The three-dimensional refractive index is a value at a measurement wavelength of 589 nm.

In addition, as a means to make the plane orientation degree (P) of an ONy film into the range mentioned above, adjusting the draw ratio at the time of ONy film manufacture, extending | stretching temperature, extending | stretching speed, the heat setting temperature after extending | stretching, etc. are mentioned.
As a draw ratio at the time of manufacture, it can be suitably drawn, for example, from 2.8 times to 4.5 times, more preferably from 3.0 times to 4.0 times.
Moreover, you may provide the difference of the draw ratio in MD direction at the time of manufacture, and TD direction. As the difference in the draw ratio in the MD direction and the TD direction during production, the difference (TD-MD) obtained by subtracting the draw ratio in the MD direction from the draw ratio in the TD direction is, for example, 0.1 or more, and more preferably It is 0.2 or more and 0.8 or less, and it can adjust in the range of 0.3 or more and 0.8 or less especially preferably.
The stretching speed at the time of manufacture, for example, at 1.0 sec ^-1 or more 20.0Sec ^-1 or less, more preferably adjusted in 1.5 sec ^-1 or more 15.0Sec ^-1 or less.
The heat setting temperature after stretching is, for example, 150 ° C. or higher and 218 ° C. or lower, more preferably 160 ° C. or higher and 215 ° C. or lower.

The dynamic friction coefficient μd ₁ between the films in the ONy film and the dynamic friction coefficient μd ₂ between the winding roll of the ONy film and the ONy film are values obtained by measurement according to JIS K7125.
The dynamic friction coefficients μd ₁ and μd ₂ indicate the slip property of the ONy film surface. The smaller the dynamic friction coefficients μd ₁ and μd _{2, the} greater the slip property of the ONy film surface. The slipping property affects the drawability, and in the present embodiment, it is preferable that μd ₁ is 0.45 or less because the drawability of the ONy film is good and the laminate processability is also good. μd ₁ is more preferably 0.40 or less. Further, it is preferable that μd ₂ is 0.3 or less because the drawability of the ONy film is good, the laminate processability is good, and the suitability for printing is provided. μd ₂ is more preferably 0.28 or less.
The film take-up roll is a film take-up roll 62 described later.

In addition, as means for setting the dynamic friction coefficients μd ₁ and μd ₂ in the above-described range, a predetermined amount of fine silica powder is added to the raw material when the ONy film is manufactured, and the cooling rate when the raw film is manufactured is adjusted. Etc.
As silica fine powder addition to the raw material, silica fine powder having an average particle size of 0.2 μm or more and 3.0 μm or less can be added to the raw material so that the content is 300 mass ppm or more and 2500 mass ppm or less. .
The cooling rate during production of the raw film is, for example, 5 ° C./second or more and 50 ° C./second or less, and more preferably 10 ° C./second or more and 30 ° C./second or less.

[Composition of laminate film]
The laminate film of this embodiment is configured by laminating one or two or more other laminate base materials on at least one surface of the above-described ONy film. Specifically, examples of other laminate base materials include an aluminum (Al) layer, a film including an aluminum layer, and a polypropylene (PP) -based or polyethylene (PE) -based seal layer (sealant layer).
In addition, the laminate film of the present embodiment is made of polyethylene terephthalate (PET), polyester resin, polyvinyl chloride (PVC), polyvinylidene chloride resin (PVDC), polyvinyl chloride on at least one surface of the above ONy film. A layer obtained by further laminating a layer (which may be a coating layer) such as a vinylidene copolymer resin, a lubricant, an antistatic agent, or a nitrified cotton amide resin may be used.
By laminating such a laminate substrate and coating layer, it is possible to improve production efficiency and transport efficiency, and to improve functionality (chemical resistance, electrical insulation, moisture resistance, cold resistance, A laminate film to which processability and the like are added can be obtained.
As a lamination | stacking aspect of the said laminate film, ONy / Al / PP, PET / ONy / Al / PP, ONy / Al / PVC is mentioned, for example. Among these, as a laminate film for PTP packaging material, a laminate mode of ONy / Al / PVC is preferable. In addition, as a laminate film for a battery exterior material, a laminate mode such as ONy / Al / PP and PET / ONy / Al / PP is preferable, and as a laminate film for in-vehicle battery, in particular, PET / ONy / Al / PP. The lamination mode is preferable.

  As the lamination mode of the laminate film, it is preferable that the ONy film is provided as a surface layer on the surface of the laminate structure because the laminate film has good sliding properties and excellent drawability. Among the laminate modes of the laminate film, ONy / Al / PVC is preferable as the laminate film for the PTP packaging material, and ONy / Al / PP is more preferable as the laminate film for the battery exterior material.

[Composition of laminate packaging material]
The laminate packaging material of this embodiment is comprised from the said laminate film. In general, a laminate packaging material including an aluminum layer is not suitable for cold forming because the aluminum layer is easily broken by necking during cold forming. In this respect, according to the laminate packaging material of the present embodiment, the above-described ONy film has excellent drawability, so that it is possible to suppress the breakage of the aluminum layer during cold deep drawing, etc. The generation of pinholes in can be suppressed. Therefore, even when the total thickness of the packaging material is thin, a molded product having a sharp shape and high strength can be obtained.

  The laminate packaging material of this embodiment preferably has an overall thickness of the ONy film and other laminate base material of 200 μm or less. When the total thickness exceeds 200 μm, it becomes difficult to form the corner portion by cold forming, and it tends to be difficult to obtain a molded product having a sharp shape.

  The thickness of the ONy film in the laminate packaging material of this embodiment is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less. Here, if the thickness of the ONy film is less than 5 μm, the impact resistance of the laminate packaging material tends to be low, and the cold formability tends to be insufficient. On the other hand, when the thickness of the ONy film exceeds 50 μm, it is difficult to obtain an effect of further improving the impact resistance of the laminate packaging material, which is not preferable because the total thickness of the packaging material is increased.

[Production equipment for biaxially stretched nylon film]
Next, a method for producing the biaxially stretched nylon film of the present embodiment will be described based on the drawings.
First, an apparatus for producing the biaxially stretched nylon film of this embodiment will be described with an example.
As shown in FIG. 1, the film manufacturing apparatus 100 includes an original fabric manufacturing apparatus 90 for manufacturing the original fabric film 1, a biaxial stretching apparatus (tubular stretching apparatus) 10 that stretches the original fabric film 1, and stretching. A first heat treatment device 20 (preheating furnace) that preheats a base film 2 that is folded later (hereinafter also simply referred to as “film 2”), a separation device 30 that separates the preheated film 2 into two upper and lower sheets, A second heat treatment device 40 that heat-treats (heat-set) the separated film 2, a tension control device 50 that applies tension to the film 2 from the downstream side when the film 2 is heat-set, and the film 2 is heat-set. And a winding device 60 for winding the biaxially stretched nylon film 3 (hereinafter also simply referred to as “film 3”).

As shown in FIG. 1, the raw fabric manufacturing apparatus 90 includes an extruder 91, a circular die 92, a water cooling ring 93, a stabilizer plate 94, and a pinch roll 95.
The tubular stretching device 10 is a device for producing a film 2 by biaxially stretching (bubble stretching) a tubular raw film 1 with the pressure of internal air. As shown in FIG. 1, the tubular stretching device 10 includes a pinch roll 11, a heating unit 12, a guide plate 13, and a pinch roll 14.
The first heat treatment apparatus 20 is an apparatus for preliminarily heat-treating the flat film 2. As shown in FIG. 1, the first heat treatment apparatus 20 includes a tenter 21 and a heating furnace 22.
As shown in FIG. 1, the separating device 30 includes a guide roll 31, a trimming device 32, separating rolls 33A and 33B, and grooved rolls 34A to 34C. Further, the trimming device 32 has a blade 321.

The second heat treatment apparatus 40 includes a tenter 41 and a heating furnace 42 as shown in FIG.
As shown in FIG. 1, the tension controller 50 includes guide rolls 51 </ b> A and 51 </ b> B and a tension roll 52.
As shown in FIG. 1, the winding device 60 includes a guide roll 61 and a winding roll 62.

[Production method of biaxially stretched nylon film]
Next, each process which manufactures a biaxially-stretched nylon film using this film manufacturing apparatus 100 is demonstrated in detail.

(Raw film production process)
As shown in FIG. 1, the raw material nylon resin is melt-kneaded by an extruder 91 and extruded into a tube shape by a circular die 92. The tubular molten resin is cooled by a water cooling ring 93. The raw film 1 is formed by rapidly cooling a molten nylon resin as a raw material by a water cooling ring 93. At this time, from the viewpoint of the dynamic friction coefficients μd ₁ and μd ₂ of the film, the cooling rate in the water cooling ring 93 is preferably 5 ° C./second or more and 50 ° C./second or less. The cooled original film 1 is folded by the stabilizer 94. The folded original fabric film 1 is sent to the next biaxial stretching process by a pinch roll 95 as a flat film.

(Biaxial stretching process)
As shown in FIG. 1, the original film 1 manufactured by the original film manufacturing process is introduced into the apparatus as a flat film by a pinch roll 11. The introduced raw film 1 is bubble-stretched by being heated with infrared rays at the heating unit 12. Thereafter, the film 2 after being bubble-stretched is folded by the guide plate 13. The folded film 2 is pinched by the pinch roll 14 and sent to the next first heat treatment step as a flat film 2.

  At this time, it can be expected that the impact strength is improved by setting the draw ratio in the MD direction and the TD direction to 2.8 times or more, respectively. Further, the difference (TD-MD) obtained by subtracting the draw ratio in the MD direction from the draw ratio in the TD direction is preferably 0.1 or more, more preferably 0.2 or more and 0.8 or less. More preferably, it is 3 or more and 0.8 or less. If the value of TD-MD is less than the above lower limit, the deep drawability of the resulting film tends to be insufficient, and the thickness accuracy of the film tends to be lowered. In particular, when the value of TD-MD is 0.1 or less, the stretching stability is inferior and the thickness accuracy of the film tends to decrease. On the other hand, when the value of TD-MD exceeds the above upper limit, the deep drawability of the resulting film tends to be insufficient, and the stretching stability tends to decrease.

(First heat treatment process)
The film 2 sent from the biaxial stretching step is at or above the shrinkage start temperature of the film 2 and about 30 ° C. higher than the melting point of the film 2 while being gripped at both ends by clips (not shown) of the tenter 21. The film 2 is preheated at a low temperature or lower and sent to the next separation step.
The heat treatment temperature in the first heat treatment is preferably 120 ° C. or higher and 190 ° C. or lower, and the relaxation rate is preferably 15% or lower.
By this first heat treatment step, the crystallinity of the film 2 is increased, and the slipping property between the overlapping films is improved.

(Separation process)
As shown in FIG. 1, the flat film 2 sent through the guide roll 31 is cut into both ends by a blade 321 of a trimming device 32 and separated into two films 2A and 2B. And film 2A, 2B is isolate | separated, interposing air between film 2A, 2B by a pair of separation roll 33A, 33B located up and down apart. The incision of the flat film 2 may be performed so that a part of the ear is generated by positioning the blade 321 slightly inward from both ends, or by positioning the blade 321 in the fold portion of the film 2. , It may be performed so that the ear does not occur.
These films 2A and 2B are overlapped again by three grooved rolls 34A to 34C positioned in order in the film flow direction, and sent to the next second heat treatment step. In addition, these grooved rolls 34A to 34C are obtained by plating the surface after the grooved processing. A good contact state between the films 2A and 2B and the air can be obtained through the grooves.

(Second heat treatment process (heat setting process))
The overlapped films 2A and 2B are heat-treated at a temperature equal to or lower than the melting point of the resin constituting the film 2 and about 30 ° C. lower than the melting point while being gripped at both ends by clips (not shown) of the tenter 41. It is (heat-set) and becomes a biaxially stretched nylon film 3 (hereinafter also referred to as film 3) having stable physical properties, and is sent to the next winding step.
The heat treatment temperature in the second heat treatment (heat setting) is preferably 190 ° C. or higher and 215 ° C. or lower. If the heat treatment temperature is less than the lower limit, the film shrinkage rate tends to increase and the risk of delamination tends to increase.On the other hand, if the upper limit is exceeded, the bowing phenomenon at the time of heat setting increases and the distortion of the film increases. Also, the density tends to be too high, and the degree of crystallinity tends to be too high, making the film difficult to deform.
In addition, the relaxation rate at this time is preferably 15% or less.
A strong tension is applied to the films 2A and 2B in the heating furnace 42 by the tension control device 50 located on the downstream side.

(Winding process)
The film 3 heat-set in the second heat treatment step is wound as films 3A and 3B on the two winding rolls 62 via the guide roll 61 via the tension control device 50.

[Modification of Embodiment]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the object and effect. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. In addition, the specific structure and shape in carrying out the present invention may be used as other structures and shapes within the scope of achieving the object and effect of the present invention.

  For example, in this embodiment, the tubular method is adopted as the biaxial stretching method, but a tenter method may be used. Furthermore, the stretching method may be simultaneous biaxial stretching or sequential biaxial stretching.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples. The characteristics in each example (three-dimensional refractive index of biaxially stretched nylon film, degree of plane orientation and plane refractive index ratio, dynamic friction coefficient, slipperiness, and deep drawability of laminate film) were evaluated by the following methods.
(I) Three-dimensional refractive index, plane orientation, and plane refractive index ratio Using RETS-100 manufactured by Otsuka Electronics Co., Ltd. By analyzing the results, the respective components Nx, Ny and Nz of the three-dimensional refractive index (measurement wavelength: 589 nm) were calculated. Further, the plane orientation degree and the plane refractive index ratio were calculated from these three-dimensional refractive index values.
(Ii) Coefficient of dynamic friction and coefficient of dynamic friction between biaxially stretched nylon films (FF) μd ₁
In accordance with JIS K 7125, the nylon films were slid at a load of 220 (unit: g) and a speed of 100 mm / min, and the coefficient at that time was measured.
-Dynamic friction coefficient μd ₂ between the winding roll and the biaxially stretched nylon film (MF)
In accordance with JIS K 7125, using a metal plate instead of a winding roll, a nylon film was slid on the metal plate at a load of 220 (unit: g) and a speed of 100 mm / min, and the coefficient at that time was measured.
In addition, the said metal plate is a metal plate which performed the smoothing process on the surface, and a smoothing process is performed by the chromium plating process, for example.
(Iii) Deep-drawing moldability The laminate film was cut to prepare a 120 × 80 mm strip piece as a sample. Using a 33 x 55 mm rectangular mold, press it with a surface pressure of 0.1 MPa, change the molding depth from 0.5 mm to 0.5 mm, and cold mold each 10 samples. (One-stage pull-in molding). The molding depth at which no pinhole was generated in any of the 10 samples in the aluminum foil was taken as the limit molding depth, and the molding depth was shown as an evaluation value. In addition, confirmation of the pinhole confirmed the transmitted light visually.
A: The limit molding depth is 7 mm or more.
○: The limit molding depth is 6 mm or more and less than 7 mm.
(Triangle | delta): The limit shaping | molding depth is 5 mm or more and less than 6 mm.
X: The limit molding depth is less than 5 mm.

[Example 1]
(Raw film production process)
As shown in FIG. 1, after Ny6 pellets were melt-kneaded at 270 ° C. in an extruder 91, the melt was extruded as a tubular film from a circular die 92, and then rapidly cooled with water (15 ° C.). Film 1 was produced.
What was used as Ny6 was Ube Industries, Ltd. nylon 6 [UBE nylon 1022FD (trade name), relative viscosity ηr = 3.5].
(Biaxial stretching process)
Next, as shown in FIG. 1, the raw film 1 is inserted between a pair of pinch rolls 11, and then heated by the heating unit 12 while a gas is being pressed into the film 1, and blown to the stretching start point to form bubbles. The biaxial stretching in the MD direction and the TD direction was performed by the tubular method by expanding and taking up with a pair of downstream pinch rolls 14. The magnification during this stretching was 3.0 times in the MD direction and 3.3 times in the TD direction.
(First heat treatment step and second heat treatment step)
Next, as shown in FIG. 1, the film 2 is subjected to heat treatment at a temperature of 170 ° C. by the first heat treatment device 20, and then passed through the separation device 30 and then heat treated at a temperature of 205 ° C. by the second heat treatment device 40. And heat fixed.
(Winding process)
Next, as shown in FIG. 1, the film 3 heat-set in the second heat treatment step is wound as two films 3 </ b> A and 3 </ b> B on two winding rolls 62 via a guide roll 61 via a tension control device 50. A biaxially stretched nylon film was produced. The thickness of the obtained biaxially stretched nylon film was 15 μm.
The obtained biaxially stretched nylon film was measured for three-dimensional refractive index, plane orientation, plane refractive index ratio, and dynamic friction coefficient. The obtained results are shown in Table 1.
(Production of laminate film)
The obtained biaxially stretched nylon film was used as a front substrate film, an aluminum foil having a thickness of 40 μm was used as an intermediate substrate, and a CPP film having a thickness of 60 μm was used as a sealant film to obtain a laminate film. The laminated film after dry lamination was aged at 40 ° C. for 3 days.
The deep drawability of the obtained laminate film was evaluated. The obtained results are shown in Table 1.

[Examples 2 to 5, Comparative Examples 1 to 7]
As Examples 2 to 5, production conditions (stretch ratio, heat setting temperature, thickness) were appropriately adjusted by the production method shown in Example 1, and biaxially stretched nylon films and laminate films were produced.
The obtained biaxially stretched nylon film was measured for three-dimensional refractive index, plane orientation, plane refractive index ratio, and dynamic friction coefficient. The obtained results are shown in Table 1. Further, the deep drawability of the obtained laminate film was evaluated. The obtained results are shown in Table 1.
On the other hand, as Comparative Examples 1 to 7, a biaxially stretched nylon film obtained by the production method shown in Table 1 was obtained. The coefficient was measured. The obtained results are shown in Table 1. Moreover, the laminate film was produced using the biaxially-stretched nylon film of Comparative Examples 1-7, and the deep drawing moldability was evaluated similarly to Example 1. FIG. The obtained results are shown in Table 1.

As is clear from the results shown in Table 1, when the degree of plane orientation of the biaxially stretched nylon film satisfies the above conditions (Examples 1 to 5), it has excellent deep drawability during cold forming. Was confirmed.
In particular, when the plane refractive index ratio (Nx / Ny) is less than 1.0065, the balance in the film surface is improved, and when μd ₁ is 0.45 or less and μd ₂ is 0.3 or less, slipperiness is achieved. Therefore, it was confirmed that the deep drawability was good when a laminate film was obtained.
On the other hand, when the plane orientation degree of the biaxially stretched nylon film does not satisfy the above conditions (Comparative Examples 3 to 7), and the dynamic friction coefficient does not satisfy the above conditions (Comparative Examples 1 to 2, 4 and 6 to 7) ), It was confirmed that the deep drawability of the laminate film obtained using this biaxially stretched nylon film was insufficient.

  The biaxially stretched nylon film of the present invention is, for example, for industrial fields (such as lithium battery packaging materials mounted on electric vehicles, tablet-type terminal devices, smartphones, etc.), pharmaceutical fields (PTP packaging materials, etc.), household goods. It can be suitably used as a packaging material that particularly requires pinhole resistance, such as packaging materials in the field (such as refill packaging for liquid detergents) and foods. The laminate packaging material of the present invention can be suitably used as a packaging material for cold molding that requires particularly excellent deep drawability.

  3, 3A, 3B ... Biaxially stretched nylon film

Claims (12)

A biaxially stretched nylon film made from nylon resin,
Of the three-dimensional refractive index of the film, the maximum refractive index value in the film plane is Nx, the minimum refractive index value in the film plane is Ny, and the refractive index value in the thickness direction of the film is Nz. In addition, the degree of plane orientation (P) satisfies the condition represented by the following mathematical formula (F1), and
Biaxially stretched nylon characterized in that the dynamic friction coefficient μd ₁ between the films in the film is 0.45 or less and the dynamic friction coefficient μd ₂ between the winding roll of the film is 0.3 or less. the film.
P = (Nx + Ny) /2−Nz≧0.042 (F1) In the biaxially stretched nylon film according to claim 1,
The plane refractive index ratio (Nx / Ny) of the said film satisfy | fills the conditions represented by following numerical formula (F2). The biaxially stretched nylon film characterized by the above-mentioned.
1.0 ≤ (Nx / Ny) ≤ 1.0065 (F2)   A laminate film comprising the biaxially stretched nylon film according to claim 1 or 2 laminated. The laminate film according to claim 3,
A laminate film characterized by being for cold forming. In the laminate film according to claim 3 or 4,
The lamination mode of the laminate film is
The biaxially oriented nylon film / aluminum layer / polypropylene layer, and
A laminate film characterized by being one of polyethylene terephthalate layer / biaxially stretched nylon film / aluminum layer / polypropylene layer. In the laminate film according to claim 3 or 4,
The laminated film is characterized in that the lamination mode of the laminated film is the biaxially oriented nylon film / aluminum layer / polyvinyl chloride layer.   The laminate film according to any one of claims 3 to 6, wherein the surface layer is the biaxially stretched nylon film.   A laminate packaging material comprising the laminate film according to any one of claims 3 to 7.   A battery comprising the laminate film according to any one of claims 3 to 7 as an exterior material. A method for producing a biaxially stretched nylon film for producing the biaxially stretched nylon film according to claim 1 or 2,
A raw film manufacturing process for forming a raw film from the raw material,
In a tubular biaxial stretching method, a biaxial stretching step of biaxially stretching the raw film,
And a heat setting step of heat-setting the film after the biaxial stretching step by performing a heat treatment. A method for producing a biaxially stretched nylon film. In the manufacturing method of the biaxially stretched nylon film according to claim 10,
In the biaxial stretching step, the stretching ratio in the MD direction and the TD direction is 2.8 times or more, respectively, and the stretching ratio in the TD direction is 0.1 times or more larger than the stretching ratio in the MD direction. A method for producing a biaxially stretched nylon film, comprising biaxially stretching a raw film. In the manufacturing method of the biaxially stretched nylon film of Claim 10 or Claim 11,
The method for producing a biaxially stretched nylon film, wherein the heat treatment temperature of the film in the heat setting step is 190 ° C. or higher and 215 ° C. or lower.