TW201347958A - Biaxially-stretched nylon film, laminate film, laminate packaging material, and manufacturing method for biaxially-stretched nylon film - Google Patents

Abstract

This biaxially-stretched nylon film has a nylon resin as a starting material, and is characterized in that P(gamma) defined in formula (A), below, is 0 or more when, among the fluorescence polarization intensities within the film surface, I parallel is the maximum value of the fluorescence polarization intensity parallel to the plane of incidence, and I perpendicular is the maximum value of the fluorescence polarization intensity perpendicular to the plane of incidence. (A) P(gamma) = (I parallel - I perpendicular) / (I parallel + I perpendicular)

Description

Biaxially stretched nylon film, laminated film, laminated packaging material and biaxially stretched nylon film manufacturing method

More particularly, the present invention relates to a method for producing a biaxially stretched nylon film, a laminate film, a laminated packaging material, and a biaxially stretched nylon film which can be preferably used as a packaging material for cold forming.

The biaxially stretched nylon film (hereinafter also referred to as an ONy film) is excellent in strength, impact resistance, pinhole resistance, and the like, and is therefore widely used for applications in which heavy load is applied to heavy goods packaging or liquid cargo packaging.

Further, it has been studied to use a laminated packaging material including the ONy film as a packaging material for cold forming which is excellent in safety or shape freedom (drawing moldability) compared to thermoforming and which can be thinned or lightened (for example). Document 1 (Japanese Patent Laid-Open Publication No. 2008-44209), and Document 2 (Japanese Patent Laid-Open Publication No. 2001-176458). Such a laminated packaging material containing an ONy film can be preferably used for battery packaging or medical packaging (PTP: Press through pack packaging materials, etc.), and daily necessities (modified packaging materials for liquid detergents, etc.) ), food and other uses.

On the other hand, the packaging material for cold forming is required to further improve the draw formability (deep drawing formability) in accordance with the large capacitance of the battery or the like. Further, the liquid detergent is also required to have a deep drawing formability when the modified packaging material is used to install a straw or the like of the injection port. Further, with the development of aging in recent years, in order to provide an excellent swallowing function (swallowing function), a medicine which is easily dissolved in water is developed, and in addition to this, the PTP packaging material requires deep drawing in addition to high moisture resistance. Formability. However, a laminate package comprising a biaxially stretched nylon membrane as described in documents 1 and 2; In the charging, although it is not a problem in usual drawing and drawing, if deep drawing is performed, pinholes may occur.

An object of the present invention is to provide a biaxially stretched nylon film, a laminated film, a laminated packaging material, and a biaxially stretched nylon film which have pinhole resistance and have excellent deep drawability at the time of cold forming.

In the present invention, the term "cold molding" refers to molding which is carried out at room temperature without heating. As one of the methods of the cold forming, a cold molding machine used for molding an aluminum foil or the like is used, and a sheet material is pressed into a master by a male mold, and pressurized at a high speed. By the above cold forming, plastic deformation such as stencil printing, bending, shearing, drawing, and the like can be produced without heating.

In order to solve the above problems, the inventors have found that there is a correlation between the arrangement of the amorphous partial sub-chains in the film plane and the draw formability. The present invention has been completed based on such findings, and provides a method for producing a biaxially stretched nylon film, a laminated film, a laminated packaging material, and a biaxially stretched nylon film as follows.

In the present invention, the term "cold molding" refers to molding which is carried out at room temperature without heating. As one of the methods of the cold forming, for example, a cold forming machine used for molding an aluminum foil or the like is used, and a sheet material is pressed into a master by a male mold, and pressurized at a high speed, by the above cold forming. Plastic deformation such as stencil printing, bending, shearing, drawing, etc. can be produced without heating.

That is, the biaxially stretched nylon membrane of the present invention is characterized in that it is made of a nylon resin as a raw material, and the maximum value of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity in the plane of the film is set to I. In parallel, when the maximum value of the fluorescence polarization intensity perpendicular to the incident surface is set to I vertical, P(γ) defined by the following formula (A) is 0 or more.

P(γ)=(I parallel-I vertical)/(I parallel+I vertical)...(A)

In the biaxially stretched nylon film of the present invention, it is preferred that the P(?) is 0.2 or more.

The biaxially stretched nylon membrane of the present invention is characterized in that the ratio of the maximum value to the minimum value (maximum value/minimum value) of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity in the plane of the film is 1.55 or less. .

The laminated film of the present invention is characterized in that it is obtained by laminating the above biaxially stretched nylon film.

In the laminated film of the present invention, a laminated substrate may be further laminated on at least one surface of the biaxially stretched nylon film.

The laminated packaging material of the present invention is characterized in that the above laminated film is used.

The method for producing a biaxially stretched nylon membrane of the present invention is characterized in that it is a method for producing the above biaxially stretched nylon membrane, and includes a step of producing a green film from the raw material forming blank film; a biaxial stretching step The green film is biaxially stretched by a tubular biaxial stretching method, and a heat fixing step is performed by heat-treating the film after the biaxial stretching step.

The method for producing a biaxially stretched nylon membrane of the present invention is characterized in that it is a method for producing a biaxially stretched nylon membrane using a nylon resin as a raw material, and includes a step of producing a green film from which the unformed green film is formed. a biaxial stretching step in which the stretching ratio of each of the MD (Machine Direction) direction and the TD (Transverse Direction) direction is 2.8 times or more, and the TD direction stretching magnification is larger than the MD direction stretching ratio And performing a biaxial stretching on the unstretched green film; and a heat fixing step of heat treating the biaxially stretched film; and parallelizing the incident surface with the fluorescent polarized light intensity in the film surface after the heat fixing step The ratio of the maximum value to the minimum value (maximum value/minimum value) of the fluorescence polarization intensity is set to 1.55 or less.

According to the present invention, it is possible to provide a biaxially stretched nylon film, a laminated film, a laminated packaging material, and a biaxially stretched nylon film which have pinhole resistance and have excellent deep drawability at the time of cold forming.

1‧‧‧film

2‧‧‧film

2A‧‧‧ film

2B‧‧‧ film

3‧‧‧film

3A‧‧‧ film

3B‧‧‧ film

10‧‧‧Tube extension

11‧‧‧Pinch roller

12‧‧‧ heating department

13‧‧‧Guideboard

14‧‧‧Pinch roller

20‧‧‧First heat treatment unit

21‧‧‧ tenter

22‧‧‧heating furnace

30‧‧‧Separation device

31‧‧‧guide roller

32‧‧‧Finishing device

321‧‧‧blade

33A‧‧‧Separation roller

33B‧‧‧Separation roller

34A‧‧‧Slotted roller

34B‧‧‧Slotted roller

34C‧‧‧Slotted roller

40‧‧‧Second heat treatment unit

41‧‧‧ tenter

42‧‧‧heating furnace

50‧‧‧Tension control device

51A‧‧·guide roller

51B‧‧·guide roller

52‧‧‧ Tension roller

60‧‧‧Winding device

61‧‧‧guide roller

62‧‧‧Winding roller

90‧‧‧Original film manufacturing equipment

91‧‧‧Extrusion machine

92‧‧‧Circular mould

93‧‧‧Water-cooled ring

94‧‧‧ Stabilization board

95‧‧‧Pinch Roller

100‧‧‧ film manufacturing equipment

Fig. 1 is a schematic configuration view showing an example of a device for producing a biaxially stretched nylon film of the present invention.

Fig. 2 is a graph showing the angular distribution of the fluorescence polarization intensity in Example 1-1.

Fig. 3 is a graph showing the angular distribution of the fluorescence polarization intensity in Comparative Example 1-1.

Fig. 4 is a graph showing the angular distribution of the fluorescence polarization intensity in Example 2-1.

Fig. 5 is a graph showing the angular distribution of the fluorescence polarization intensity in Comparative Example 2-1.

<First embodiment>

Hereinafter, the preferred embodiments of the present invention will be described in detail.

[Composition of biaxially stretched nylon membrane]

The biaxially stretched nylon film (ONy film) of the present embodiment is formed by biaxially stretching a green film made of a nylon resin as a raw material and thermally fixing it at a specific temperature.

As the nylon resin which is a raw material, nylon 6, nylon 8, nylon 11, nylon 12, nylon 6, 6, nylon 6, 10, nylon 6, 12 or the like can be used. In terms of physical properties, melting properties, and ease of use, nylon 6 (hereinafter also referred to as Ny6) is preferably used.

Here, the chemical formula of the above Ny6 is shown in the following formula (1).

H-[NH-(CH ₂ ) ₅ -CO] _n -OH. . . (1)

The number average molecular weight of the nylon resin as a raw material is preferably 15,000 or more and 30,000 or less, more preferably 22,000 or more and 24,000 or less.

If the number average molecular weight of the nylon resin is less than 15,000, the impact strength or tensile strength may be insufficient. If it exceeds 30,000, an excessive load is applied during extrusion molding, and an appropriate extrusion amount is not easily obtained. As a result, manufacturing efficiency is reduced.

In the present embodiment, the maximum value of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity of the ONy film is set to I parallel, and the maximum value of the fluorescence polarization intensity perpendicular to the incident surface is set to I. When it is vertical, P(γ) defined by the following formula (A) must be 0 or more.

P(γ)=(I parallel-I vertical)/(I parallel+I vertical)...(A)

The fluorescence polarization measurement is performed by measuring the distribution of the distribution of the amorphous partial daughter strands in the plane of the film. First, a specific size is cut out from a specific portion, preferably a central portion, of the film to be measured. Then, the cut slice was immersed in an aqueous solution containing a fluorescent agent at room temperature for a specific period of time, washed with water, air-dried, and used as a measurement sample. Then, using a fluorescence spectrophotometer, a polarizing element analyzer is used to obtain a fluorescence intensity in the plane of the measurement sample parallel to the incident surface by a transmission method at a wavelength of 365 nm and a fluorescence wavelength of 420 nm. The angular intensity of the fluorescent polarization and the intensity of the fluorescent polarization perpendicular to the incident surface. The maximum value among the respective angular distributions is set to I parallel and I is perpendicular, and is substituted into the above formula (A) to calculate P(γ).

When P(γ) is in the above range, a uniform amorphous partial chain in all directions in the film plane is arranged, so that it is possible to obtain a deep drawing which is excellent in pinhole resistance and excellent in cold forming. Biaxially stretched nylon membrane. When P(?) is less than 0, the draw formability of the obtained film is largely deteriorated, and the impact strength is also lowered. Among them, P(γ) is preferably 0.05 or more, more preferably 0.1 or more, and particularly preferably 0.2 or more in terms of the uniformity of the arrangement of the uniform amorphous partial sub-chains in all directions in the plane.

P(γ) can be controlled by appropriately adjusting the manufacturing conditions (stretching ratio, heat setting temperature, etc.).

[Composition of laminated film]

The laminated film of the present embodiment is formed by laminating one or more layers of other laminated base materials on at least one of the ONY films. Specifically, examples of the other laminated base material include an aluminum layer or a film containing an aluminum layer, or a polypropylene-based or polyethylene-based sealing layer (sealant layer).

Further, in the laminated packaging material of the present embodiment, polyethylene terephthalate (PET), polyester resin, polyvinylidene chloride resin, or poly layer may be laminated on at least one surface of the ONY film. Coatings such as vinylidene chloride copolymer resin, lubricant, antistatic agent or nitrocellulose amide resin.

By laminating such a laminated substrate, it is possible to improve the manufacturing efficiency and improve the transport efficiency, and to obtain additional functionality (chemical resistance, electrical insulation, moisture resistance, cold resistance, workability, etc.) Laminated film.

Examples of the laminated aspect of the laminated film include ONy/Al/PP and PET/ONy/Al/PP.

[Composition of laminated packaging materials]

The laminated packaging material of the present embodiment includes the laminated film described above. In general, a laminated packaging material comprising an aluminum layer is not suitable for cold forming because it is liable to be broken due to necking in the aluminum layer during cold forming. In this aspect, according to the laminated packaging material of the present embodiment, since the ONy film has excellent drawing formability, it is possible to suppress breakage of the aluminum layer during deep drawing or the like in a cold environment, and it is possible to suppress the packaging. Pinholes are produced in the material. Therefore, even in the case where the total thickness of the packaging material is thin, a molded article having a sharp angular shape and high strength can be obtained.

In the laminated packaging material of the present embodiment, the thickness of the entire ONy film and the other laminated substrate is preferably 200 μm or less. When the thickness of the whole is more than 200 μm, there is a tendency that it is difficult to form a corner portion by cold forming, and it is difficult to obtain a molded article having a sharply defined shape.

The thickness of the ONy film in the laminated packaging material of the present embodiment is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less. When the thickness of the ONy film is less than 5 μm, the impact resistance of the laminated packaging material is lowered, and the cold moldability 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 laminated packaging material, and the total thickness of the packaging material is increased, which is not preferable.

[Manufacturing device for biaxially stretched nylon membrane]

Next, a method of manufacturing the biaxially stretched nylon film of the present embodiment will be described based on the drawings.

First, an example of the apparatus for producing the biaxially stretched nylon film of the present embodiment will be described.

As shown in FIG. 1, the film manufacturing apparatus 100 includes: an original sheet manufacturing apparatus 90 for manufacturing a green film 1; a biaxial stretching apparatus (tubular extension apparatus) 10 for extending the green film 1; and a first heat treatment apparatus 20 (preheating furnace), which preheats the stretched base film 2 (hereinafter, also simply referred to as "film 2"); the separating device 30 separates the preheated film 2 into two upper and lower sheets; a second heat treatment device 40 that heat-treats (heat-fixes) the separated film 2; a tension control device 50 that applies tension to the film 2 from the downstream side when heat-fixing the film 2; and a winding device 60 The biaxially stretched nylon film 3 (hereinafter, also simply referred to as "film 3") obtained by thermally fixing the film 2 is taken up.

As shown in FIG. 1, the original sheet manufacturing apparatus 90 includes an extruder 91, a circular dies 92, a water-cooling ring 93, a stabilizing plate 94, and a pinch roller 95.

The tubular extension device 10 is a device for manufacturing the membrane 2 by biaxially stretching (bubble extending) the tubular green film 1 by the pressure of the internal air. As shown in FIG. 1, the tubular stretching device 10 includes a pinch roller 11, a heating portion 12, a guide sheet 13, and a pinch roller 14.

The first heat treatment device 20 is a device for previously heat-treating the flat film 2. As shown in FIG. 1, the first heat treatment device 20 includes a tenter 21 and a heating furnace 22.

As shown in Fig. 1, the separating device 30 includes a guide roller 31, a dressing device 32, separation rollers 33A, 33B, and grooved rollers 34A to 34C. Further, the dressing device 32 has a blade 321.

As shown in FIG. 1, the second heat treatment device 40 includes a tenter 41 and a heating furnace 42.

As shown in FIG. 1, the tension control device 50 includes guide rollers 51A, 51B, and a tension roller 52.

As shown in FIG. 1, the take-up device 60 includes a guide roller 61 and a take-up roller 62.

[Manufacturing method of biaxially stretched nylon membrane]

Next, each step of manufacturing the biaxially stretched nylon film using the film production apparatus 100 will be described in detail.

(blank film manufacturing step)

As a raw material, the nylon resin is melt-kneaded by an extruder 91 as shown in Fig. 1, and is extruded into a tubular shape by a circular die 92. The tubular molten resin is cooled by the water-cooling ring 93. The green film 1 is formed by rapidly cooling a molten nylon resin as a raw material by a water-cooling ring 93. The cooled green film 1 is folded by the stabilizing plate 94. The folded green film 1 is fed as a flat film to the subsequent biaxial stretching step by the pinch rolls 95.

(biaxial extension step)

The green film 1 produced by the green film production step is introduced into the inside of the apparatus as a flat film by the pinch rolls 11 as shown in Fig. 1 . The introduced green film 1 is bubbled by heating it by the infrared rays in the heating portion 12. Thereafter, the film 2 in which the bubbles are extended is folded by the guide sheets 13. The folded film 2 is clamped by the pinch rolls 14 and sent as a flat film 2 to the next first heat treatment step.

In this case, it is preferable that the stretching ratios in the MD direction and the TD direction are respectively 2.8 times or more. When the stretching ratio in the MD direction and the TD direction is less than 2.8 times, the impact strength is lowered and there is a tendency for practical use.

Further, the difference (TD-MD) obtained by subtracting the stretching ratio in the MD direction from the TD direction is preferably 0.1 times or more, more preferably 0.2 times or more and 0.8 times or less, still more preferably 0.3 times or more and 0.8. Less than the following. When the value of TD-MD does not reach the above lower limit, the deep drawing formability of the obtained film tends to be insufficient, and the thickness precision of the film tends to decrease. Further, particularly when the value of TD-MD is 0.1 times or less, the elongation stability is deteriorated and the thickness precision of the film tends to be lowered. On the other hand, when the value of TD-MD exceeds the above upper limit, the deep draw moldability of the obtained film tends to be insufficient, and the elongation stability tends to be lowered.

(first heat treatment step)

The film 2 conveyed from the biaxial stretching step is held at both ends by a jig (not shown) of the tenter 21, and is higher than the shrinkage start temperature of the film 2 and lower than the melting point of the film 2. The film 2 is heat-treated in advance at a temperature of 30 ° C or lower and sent to the next separation step.

The heat treatment temperature in the first heat treatment is preferably 120 ° C or more and 190 ° C or less, and the relaxation rate is preferably 15% or less.

By the first heat treatment step, the crystallinity of the film 2 is increased, so that the slidability of the superposed films becomes good.

(separation step)

The flat film 2 conveyed by the guide roller 31 is separated into two sheets 2A and 2B by cutting the both ends by the blade 321 of the dressing device 32 as shown in Fig. 1 . Then, the membranes 2A and 2B are separated from each other by interposing the separation rollers 33A and 33B at a position separated from the upper and lower sides while interposing air between the membranes 2A and 2B. The slitting of the flat film 2 can be performed by partially forming the flange portion by the blade 321 located slightly inside from the both end portions, or by locating the blade 321 at the crease portion of the film 2. This is done without creating a flange portion.

The films 2A, 2B are again superposed by the three grooved rolls 34A to 34C sequentially located in the flow direction of the film and sent to the next second heat treatment step. Further, the grooved rolls 34A to 34C are formed by plating the surface after the grooved processing. A good contact state of the films 2A, 2B with the air can be obtained through the grooves.

(second heat treatment step (heat setting step))

The film 2A and 2B in the overlapped state are heat-treated at a temperature lower than the melting point of the resin constituting the film 2 and at a temperature lower than the melting point by about 30 ° C while being held by the jig (not shown) of the tenter 41. (Heat-fixing), it becomes a biaxially stretched nylon film 3 (hereinafter, also referred to as film 3) which is stable in 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 more and 215 ° C or less. When the heat treatment temperature is less than the above lower limit, the film shrinkage ratio increases, and the risk of peeling tends to increase. On the other hand, if the heat treatment temperature exceeds the above upper limit, the following tendency is observed: heat The warpage phenomenon at the time of fixation increases, the strain of the film increases, and the density becomes too high and the crystallinity becomes too high to make deformation of the film difficult.

Further, the relaxation rate at this time is preferably 15% or less.

Further, a strong tension is applied to the films 2A, 2B in the heating furnace 42 by the tension control device 50 located on the downstream side.

(rolling step)

The film 3 thermally fixed by the second heat treatment step passes through the tension control device 50, and is taken up as a film 3A, 3B to the two take-up rolls 62 via the guide rolls 61.

<Second embodiment>

In the description of the second embodiment, the same or similar components as those in the first embodiment are denoted by the same reference numerals or names, and the description thereof will be omitted or simplified.

[Composition of biaxially stretched nylon membrane]

The biaxially stretched nylon film (ONy film) of the present embodiment is formed by biaxially stretching a green film made of a nylon resin as a raw material and thermally fixing it at a specific temperature.

As the raw material, that is, the nylon resin, nylon-6, nylon-8, nylon-11, nylon-12, nylon 6,6, nylon 6,10, nylon 6,12, or the like can be used. In terms of physical properties, melting properties, and ease of use, nylon-6 (hereinafter also referred to as Ny6) is preferably used.

Here, the chemical formula of the above Ny6 is shown in the following formula (1).

H-[NH-(CH ₂ ) ₅ -CO] _n -OH. . . (1)

The number average molecular weight of the nylon resin as a raw material is preferably 15,000 or more and 30,000 or less, more preferably 22,000 or more and 24,000 or less.

If the number average molecular weight of the nylon resin is less than 15,000, the impact strength or tensile strength may be insufficient. If it exceeds 30,000, an excessive load is applied during extrusion molding, and an appropriate extrusion amount is not easily obtained. As a result, manufacturing efficiency is reduced.

In the present embodiment, the ratio of the maximum value to the minimum value (maximum value/minimum value) of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity in the film plane must be 1.55. under.

The fluorescence polarization measurement is performed by measuring the distribution of the distribution of the amorphous partial daughter strands in the plane of the film. First, a specific size is cut out from a specific portion, preferably a central portion, of the film to be measured. Then, the cut slice was immersed in an aqueous solution containing a fluorescent agent at room temperature for a specific period of time, washed with water, air-dried, and used as a measurement sample. Then, using a fluorescence spectrophotometer, a polarizing element analyzer is used to obtain a fluorescence polarization intensity in the plane of the measurement sample parallel to the incident surface by a transmission method at a wavelength of 365 nm and a fluorescence wavelength of 420 nm. The angular distribution of the fluorescence intensity. Set the maximum value to the maximum value and the minimum value to the minimum value to calculate the ratio.

When the fluorescence polarization ratio is within the above range, a uniform amorphous partial sub-chain in all directions in the film surface is arranged, so that biaxially stretched nylon having excellent deep drawability at the time of cold forming can be obtained. membrane. If the ratio of the fluorescence polarization intensity (maximum/minimum value) exceeds 1.55, the deep draw formability of the obtained film becomes insufficient. Among them, the fluorescence polarization intensity ratio (maximum value/minimum value) is particularly preferably 1.45 or less in terms of the uniformity of the arrangement of the uniform amorphous partial sub-chains in all directions in the plane.

[Modification of Embodiment]

Furthermore, the above-described aspects are illustrative of one aspect of the present invention, and the present invention is not limited to the above-described embodiments, and of course, modifications or improvements including the constitution of the present invention and achieving the objects and effects are included. In the context of the present invention. Further, the specific structure and shape of the present invention are equivalent to the purpose and effect of the invention, and there is no problem in other configurations or shapes.

For example, in the first embodiment, the tubular method is employed as the biaxial stretching method, but the tenter method may be employed. Further, as the stretching method, both the biaxial stretching and the sequential biaxial stretching can be performed at the same time.

In the second embodiment, the tubular method is used as a method for producing a biaxially stretched nylon film, but as long as the fluorescence polarization in the plane of the film is parallel to the incident surface. When the ratio of the light intensity (maximum/minimum value) is 1.55 or less, the tenter method can also be used. Further, as the stretching method, both the biaxial stretching and the sequential biaxial stretching can be performed at the same time.

Example

Hereinafter, the present invention will be described in further detail by way of examples and comparative examples, but the invention is not limited by the examples.

<Example of the first embodiment>

In the first embodiment, the characteristics in each example (the fluorescence polarization intensity evaluation P(γ) in the film surface and the deep drawing moldability of the laminated packaging material) were evaluated by the following methods.

(i) Fluorescence polarization intensity evaluation P(γ)

A section of 3 cm × 7 cm was cut out from the central portion of the biaxially stretched nylon membrane opened in A4, and immersed in an aqueous solution containing 0.2% of a fluorescent agent (manufactured by Sumitomo Chemical Co., Ltd.: Whitex RP) at room temperature (23 ° C). After 4 hours, it was washed with water and air-dried for measurement.

In the measurement, a fluorescence spectrophotometer FOM-1 manufactured by JASCO Corporation was used, and a polarizing element analyzer was used under the conditions of an excitation light wavelength of 365 nm and a fluorescence wavelength of 420 nm by a transmission method, and the measurement sample was obtained in-plane. The intensity of the fluorescent polarization parallel to the incident surface and the angular distribution of the intensity of the fluorescent polarization perpendicular to the incident surface. The excitation beam was incident from the back side of the measurement sample. The angular distribution in the angular distribution diagrams shown in Figs. 2 and 3 is the fluorescence intensity, and the circumferential direction is the angle θ. The maximum value among the respective angular distributions is set to I parallel, I is perpendicular, and is substituted into the following formula (A), thereby calculating P(γ).

P(γ)=(I parallel-I vertical)/(I parallel+I vertical)...(A)

(ii) Deep drawing formability

The laminated film was cut to prepare a short strip of 120 × 80 mm as a sample. A rectangular mold of 33 × 55 mm was used, and the surface pressure was pressed at 0.1 MPa, and the molding depth was changed in units of 0.5 mm from the molding depth of 0.5 mm, and each of the 10 samples was cold-formed (introduction molding) . Then, the molding depth of any of the ten samples on the aluminum foil without pinholes was set as the ultimate molding depth, and the molding depth was expressed as evaluation. value. Further, the confirmation of the pinholes was confirmed by visual observation of the transmitted light.

A: The ultimate forming depth is 7 mm or more.

B: The ultimate forming depth is 5 mm or more and less than 7 mm.

C: The ultimate forming depth is less than 5 mm.

[Example 1-1] (blank film manufacturing step)

As shown in Fig. 1, the Ny6 pellets were melt-kneaded in an extruder 91 at 275 ° C, and then the melt was extruded from a circular die 92 as a tubular film, followed by rapid cooling with water (15 ° C). Blank film 1.

Nylon 6 [UBE Nylon 1022FD (trade name), relative viscosity ηr = 3.5] manufactured by Ube Co., Ltd., Ny6.

(biaxial extension step)

Then, as shown in FIG. 1, after the green film 1 is inserted between the pair of pinch rolls 11, the gas is pressed into the space by heating the heating portion 12, and the air is blown toward the extension start point. This is expanded into a bubble, and is pulled by the pinch roller 14 by one of the downstream sides, thereby performing simultaneous biaxial stretching in the MD direction and the TD direction by the tubular method. The magnification at the time of this extension was 2.95 times in the MD direction and 3.25 times in the TD direction.

(first heat treatment step and second heat treatment step)

Then, 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 thereafter, after passing through the separation device 30, heat treatment is performed at a temperature of 200 ° C by the second heat treatment device 40. And heat-fixed.

(rolling step)

Then, as shown in FIG. 1, the film 3 thermally fixed by the second heat treatment step is passed through the tension control device 50 and taken up as a film 3A, 3B to the two take-up rolls 62 via the guide rolls 61, thereby manufacturing Biaxially stretched nylon membrane. The biaxially stretched nylon film obtained had a thickness of 15 μm.

The intensity of the fluorescent light polarized parallel to the incident surface in the plane of the obtained biaxially stretched nylon film and the intensity of the fluorescent light perpendicular to the incident surface in the plane were measured, and P(γ) was calculated according to the above formula (A). . The results obtained are shown in Table 1. Further, the angular distribution of the fluorescence polarization intensity is shown in Fig. 2 .

(production of laminated film)

The biaxially stretched nylon film obtained was used as a surface base film, and an aluminum foil having a thickness of 40 μm was used as an intermediate substrate, and a CPP (cast polypropylene) film having a thickness of 60 μm was used as a sealant film by dry lamination. A laminated film is obtained. Further, the laminated film after dry lamination was aged at 40 ° C for 3 days.

The deep draw formability of the obtained laminated film was evaluated. The results obtained are shown in Table 1.

[Examples 1-2 to 1-6, Comparative Examples 1-1 to 1-4]

As Examples 2 to 6, the production conditions (stretching ratio, heat setting temperature, and thickness) were appropriately adjusted by the production method shown in Example 1-1 to prepare a biaxially stretched nylon film and a laminated film.

The intensity of the fluorescent light polarized parallel to the incident surface in the plane of the obtained biaxially stretched nylon film and the intensity of the fluorescent light perpendicular to the incident surface in the plane were measured, and P(γ) was calculated according to the above formula (A). . The results obtained are shown in Table 1. Further, the deep draw moldability of the obtained laminated film was evaluated. The results obtained are shown in Table 1.

On the other hand, as a comparative example 1-1 to 1-4, the biaxially stretched nylon film obtained by the manufacturing method shown in Table 1 was obtained, and P (γ) was computed similarly to Example 1-1. The results obtained are shown in Table 1. Further, the angular distribution of the fluorescent polarization intensity in the biaxially stretched nylon film of Comparative Example 1-1 is shown in Fig. 3 . Further, a laminated film was produced using the biaxially stretched nylon film of Comparative Examples 1-1 to 1-4, and the deep drawing formability was evaluated in the same manner as in Example 1-1. The results obtained are shown in Table 1.

[Table 1]

It can be clearly confirmed from the results shown in Table 1 that in the case where the fluorescence intensity of the biaxially stretched nylon film is P (γ) of 0 or more (Examples 1-1 to 1-6), it is cold. Good deep drawing formability during molding. It can be clearly confirmed from Fig. 2 that the angular distributions of I parallel and I perpendicular respectively show a substantially circular shape, and the maximum value of I parallel is greater than the maximum value of I vertical.

On the other hand, in the case where the P(γ) of the fluorescent polarization in the plane of the biaxially stretched nylon film is less than 0 (Comparative Examples 1-1 to 1-4), the biaxially stretched nylon film is used. The deep drawing formability of the laminated packaging material is insufficient. It can be clearly confirmed from Fig. 3 that the distribution of I parallel and I perpendicular shows a skew shape in which the intensity in the longitudinal and lateral directions is large but the intensity in the oblique direction is small, and the maximum value of I parallel is smaller than the maximum value of I vertical. Further, in Comparative Examples 1-1 to 1-4, the impact strength also decreased.

<Embodiment of Second Embodiment>

In the second embodiment, the characteristics in each example (the ratio of the fluorescence polarization intensity (maximum value/minimum value) parallel to the incident surface in the film plane and the deep drawing formability of the laminated packaging material) were evaluated by the following methods. .

(i) Fluorescence polarization intensity ratio (maximum/minimum value)

A section of 3 cm × 7 cm was cut out from the central portion of the biaxially stretched nylon membrane opened in A4, and immersed in an aqueous solution containing 0.2% of a fluorescent agent (manufactured by Sumitomo Chemical Co., Ltd.: Whitex RP) at room temperature (23 ° C). After 4 hours, it was washed with water and air-dried for measurement.

In the measurement, a fluorescence spectrophotometer FOM-1 manufactured by JASCO Corporation was used, and a polarizing element analyzer was used under the conditions of an excitation light wavelength of 365 nm and a fluorescence wavelength of 420 nm by a transmission method to obtain an in-plane measurement sample. An angular distribution of the intensity of the fluorescent polarization parallel to the incident surface. Furthermore, the measurement of the intensity of the fluorescent polarization perpendicular to the incident surface in the plane of the polarizing element analyzer is omitted. The excitation beam was incident from the back side of the measurement sample. The angular distribution in the angular distribution diagrams shown in Figs. 4 and 5 is the fluorescence intensity, and the circumferential direction is the angle θ. Set the largest value to the maximum value, the minimum value to the minimum value, and calculate the ratio.

(ii) Deep drawing formability

The laminated packaging material was cut to prepare a short strip of 120 × 80 mm as a sample. A rectangular mold of 33 × 55 mm was used, and the surface pressure was pressed at 0.1 MPa, and the molding depth was changed in units of 0.5 mm from the molding depth of 0.5 mm, and each of the 10 samples was cold-formed (introduction molding) . Then, the molding depth at which no pinhole was formed on the aluminum foil on any of the ten samples was set as the ultimate molding depth, and the molding depth was expressed as an evaluation value.

Further, the confirmation of the pinholes was confirmed by visual observation of the transmitted light.

A: The ultimate forming depth is 7 mm or more.

B: The ultimate forming depth is 6 mm or more and less than 7 mm.

C: The ultimate forming depth is less than 5 mm.

[Example 2-1] (blank film manufacturing step)

As shown in Fig. 1, after the Ny6 pellets were melt-kneaded in an extruder 91 at 275 ° C, the melt was extruded from a circular die 92 as a tubular film, followed by water (15 ° C). The green film 1 was produced by quenching.

Nylon 6 [UBE Nylon 1022FD (trade name), relative viscosity ηr = 3.5] manufactured by Ube Co., Ltd., Ny6.

(biaxial extension step)

Then, as shown in FIG. 1, after the green film 1 is inserted between the pair of pinch rolls 11, the gas is pressed into the space by heating the heating portion 12, and the air is blown toward the extension start point. This is expanded into a bubble, and is pulled by the pinch roller 14 by one of the downstream sides, thereby performing simultaneous biaxial stretching in the MD direction and the TD direction by the tubular method. The magnification at the time of this extension 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)

Then, 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 thereafter, after passing through the separation device 30, heat treatment is performed at a temperature of 200 ° C by the second heat treatment device 40. And heat-fixed.

(rolling step)

Then, as shown in FIG. 1, the film 3 thermally fixed by the second heat treatment step is passed through the tension control device 50, and is taken up as a film 3A, 3B to the two take-up rolls 62 via the guide rolls 61, thereby A biaxially stretched nylon membrane is produced. The biaxially stretched nylon film obtained had a thickness of 15 μm.

The ratio of the fluorescence polarization intensity (maximum value/minimum value) parallel to the incident surface in the plane of the obtained biaxially stretched nylon film was measured. The results obtained are shown in Table 2. Further, the angular distribution of the fluorescence polarization intensity is shown in Fig. 4 .

(Production of laminated packaging materials)

The biaxially stretched nylon film obtained was used as a surface base film, and 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, and a laminated product was obtained by dry lamination. Further, the dry laminated laminated product was aged at 40 ° C for 3 days.

The deep drawability of the obtained laminated packaging material was evaluated. The results obtained are shown in Table 2.

[Examples 2-2 to 2-7, Comparative Examples 2-1 to 2-5]

As Examples 2-2 to 2-7, the production conditions (stretching ratio, heat setting temperature) were appropriately adjusted by the production method shown in Example 2-1 to prepare a biaxially stretched nylon film (thickness: 15 μm).

In the biaxially stretched nylon film obtained in each of Examples 2-2 to 2-7, the fluorescence polarization intensity ratio (maximum value/minimum value) was also measured in the same manner as in Example 2-1. The results obtained are shown in Table 2.

On the other hand, as a comparative example 2-1 to 2-5, a biaxially stretched nylon film (thickness: 15 μm) produced by the production method shown in Table 2 was obtained, and fluorescence polarization was measured in the same manner as in Example 2-1. Intensity ratio (maximum/minimum).

Further, the angular distribution of the fluorescent polarized light intensity in the biaxially stretched nylon film of Comparative Example 2-1 is shown in Fig. 5 .

Further, in Examples 2-2 to 2-7 and Comparative Examples 2-1 to 2-5, a laminated packaging material was produced in the same manner as in Example 2-1, and the obtained laminated packaging material was deeply drawn. Moldability was evaluated. The results obtained are shown in Table 2.

From the results shown in Table 2, it was also confirmed that the ratio of the fluorescence polarization intensity (maximum value/minimum value) parallel to the incident surface in the plane of the biaxially stretched nylon film was 1.55 or less (Example 2-1) ~2-7), has good deep drawability during cold forming. As is clear from Fig. 4, the intensity of the fluorescent light in the plane of the film is substantially circular. Further, it was confirmed that the elongation stability of the biaxially stretched nylon films was also good.

On the other hand, in the case where the ratio of the fluorescence polarization intensity (maximum value/minimum value) parallel to the incident surface in the plane of the biaxially stretched nylon film exceeds 1.55 (Comparative Examples 2-1 to 2-5), the double is used. The deep drawing formability of the laminated packaging material obtained by stretching the nylon film by the shaft is insufficient. As is clear from Fig. 5, the intensity in the longitudinal and lateral directions is large but the intensity in the oblique direction is small.

Claims (8)

A biaxially stretched nylon membrane characterized in that it is made of a nylon resin; the maximum value of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity in the plane of the film is set to I parallel, and When the maximum value of the fluorescence polarization intensity perpendicular to the incident surface is set to I vertical, P(γ) defined by the following formula (A) is 0 or more; P(γ)=(I parallel-I vertical)/(I Parallel + I vertical)... (A). A biaxially stretched nylon membrane according to claim 1, wherein said P(?) is 0.2 or more. A biaxially stretched nylon membrane characterized in that it is made of a nylon resin; and the ratio of the maximum value to the minimum value of the fluorescence polarization intensity parallel to the incident surface of the fluorescent polarization in the plane of the film (maximum The value/minimum value is 1.55 or less. A laminated film characterized in that the laminated layer is a biaxially stretched nylon film according to any one of claims 1 to 3. The biaxially stretched nylon film of claim 4, which is formed by laminating at least one side of the biaxially stretched nylon film and then laminating the substrate. A laminated packaging material characterized by using a laminate film as claimed in claim 4. A method for producing a biaxially stretched nylon membrane, which is characterized in that it is a biaxially stretched nylon membrane according to claim 1 or 2, and comprises a step of producing a green film from the raw material forming blank; And an extension step of biaxially stretching the green film by a tubular biaxial stretching method; and a heat fixing step of thermally fixing the film after the biaxial stretching step. A method for producing a biaxially stretched nylon membrane, which is characterized in that it is a method for producing a biaxially stretched nylon membrane using a nylon resin as a raw material, and includes a step of producing a blank film from which the unformed blank film is formed; a biaxial stretching step of biaxially stretching the unextended blank film under the condition that the stretching ratio of each of the MD direction and the TD direction is 2.8 times or more and the stretching ratio in the TD direction is larger than the stretching ratio in the MD direction; a heat setting step of performing heat treatment on the biaxially stretched film; and ratio of a maximum value to a minimum value of the fluorescence polarization intensity parallel to the incident surface in the fluorescence polarization intensity in the film surface after the heat setting step ( The maximum/minimum value is set to 1.55 or less.