JP3499206B2 - Multilayer stretched polyamide film - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has excellent transparency, tensile strength, delamination strength, pinhole resistance, gas barrier property, and dimensional stability, as well as excellent retort resistance (hot water treatment resistance). The present invention relates to a multilayer stretched polyamide film suitable for packaging applications.

[0002]

2. Description of the Related Art A large amount of various plastic film packaging bags are used for packaging foods, pharmaceuticals, sundries, etc. Usually, a biaxially stretched plastic film is used as a base film and a heat-sealable sealant film ( For example, a laminated film obtained by laminating a non-oriented film) is used. The base film is required to have excellent properties such as transparency, pinhole resistance, gas barrier property, dimensional stability, and tensile strength, and has excellent delamination strength with the sealant film. It is necessary. However, due to the recent demand for long-term storability of packaging contents, a film in which a vinylidene chloride-based polymer latex is coated on the surface of a biaxially stretched polyamide film is widely used in order to impart a high gas barrier property. However, there is a drawback that it becomes cloudy due to hot water treatment, and there is an environmental problem.

A film using polymethaxylylene adipamide (hereinafter referred to as MXD6) synthesized from adipic acid and metaxylylenediamine as a raw material is excellent in gas barrier property but has pinhole resistance. Since it is inferior, a multilayer film has been proposed which is mixed with another polyamide resin, coextruded with a resin layer of polyamide, polyester, polyolefin or the like, or laminated.

For example, a biaxially stretched film formed from a mixture of MXD6 and an aliphatic polyamide (JP-A-48)
No. 54176), a biaxially stretched film in which MXD6 and an aliphatic polyamide are laminated by a tubular method (JP-A-57-51427), a surface layer made of a mixture of MXD6 and an aliphatic polyamide, and mainly MXD6. Three-layer film having an intermediate layer (JP-A-56-155)
762), a multilayer film (JP-A-4-59244) in which at least one layer is composed of MXD6 and / or a mixture of an aliphatic polyamide and an amorphous polyamide, and the like.

However, it is difficult for a biaxially stretched film produced using a raw material in which MXD6 and an aliphatic polyamide are simply mixed, to have both gas barrier property and pinhole resistance, and the aliphatic polyamide and MXD6 are also difficult to achieve.
In the case of laminating, there was a drawback that delamination was likely to occur. Further, even in the case of the structure disclosed in the above-mentioned JP-A-56-155762, the pinhole resistance is insufficient and there is a problem of delamination phenomenon. In addition, JP-A-4-5
According to the method disclosed in Japanese Patent No. 9244, the problem of the delamination phenomenon is improved, but the performance such as pinhole resistance is insufficient when applied to a wide range of applications.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks, has excellent transparency, tensile strength, delamination strength, gas barrier property, dimensional stability, and excellent retort resistance. Another object of the present invention is to provide a multilayer stretched polyamide film suitable for packaging applications at an economical price. That is, specifically, the aliphatic polyamide resin layer and the MXD
Delamination does not occur between the 6 resin layers, and in addition to the excellent mechanical properties, pinhole resistance, and transparency of the aliphatic polyamide resin layer, it also has the heat resistance and gas barrier properties of the MXD6 resin layer. Another object of the present invention is to provide a multilayer stretched polyamide film suitable as a packaging material.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that a multilayer stretched film laminated with a composition comprising specific components can solve these problems. And has reached the present invention.

That is, the gist of the present invention is as follows. (1) In at least one layer, a polyamide (A) mainly composed of a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms is 99 to 75% by mass,
A multilayer stretched polyamide film having a resin layer (X) comprising 1 to 25% by mass of polybutylene terephthalate or a polyester mainly composed of polybutylene terephthalate. (2) The multilayer stretched polyamide film as described in (1) above, which has at least two layers of a resin layer (X) and a resin layer (Y) made of an aliphatic polyamide (B). (3) Polyamide (A) and / or amorphous polyamide (C) is 50 in the middle of the resin layer (X) and the resin layer (Y).
-80 mass% and polyamide (B) 50-20 mass%
The multilayer stretched polyamide film according to (1) or (2) above, which has at least three layers and has a polyamide resin layer (Z) in the ratio of (4) The multilayer stretched polyamide film according to any one of (1) to (3) above, wherein the polyester is a modified polybutylene terephthalate obtained by copolymerizing polytetramethylene glycol as a diol component. (5) 0.01 to 0.5% by mass of talc in the resin layer (X)
The multilayer stretched polyamide film according to any one of (1) to (4) above, which is contained. (6) The multilayer stretched polyamide film according to any one of the above (1) to (5), wherein the multilayer stretched film comprises 5 layers of Y / Z / X / Z / Y. (7) Oxygen permeability is 100 ml / (m ² · d · MPa)
The multilayer stretched polyamide film according to any one of the above (1) to (6), which is as follows.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The multilayer stretched polyamide film of the present invention comprises
Polyamide (A) mainly composed of a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms and polybutylene terephthalate (PBT) or a polyester mainly containing at least one of its constituent layers Of 99 to 75/1 to 25 (mass%), preferably 97 to 80/3 to 20 (mass%). When the compounding amount of PBT or the polyester mainly composed of PBT in the resin layer (X) is less than 1% by mass, the effect of improving the pinhole resistance of the film is insufficient, and when it exceeds 25% by mass. It is not preferable because the oxygen permeability of the film is lowered and the haze is increased.

The polyamide (A) is a polyamide mainly obtained by a polycondensation reaction of a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms,
Particularly, polymethaxylylene adipamide (MXD6) synthesized from metaxylylene and adipic acid is preferable.

The PBT used in the present invention has a terephthalic acid component and a 1,4-butanediol component as main components, and is subjected to a melt polycondensation reaction or subsequently solid phase polymerization.

Other components may be appropriately copolymerized with PBT as long as the effects of the present invention are not impaired. Examples of the acid component as a copolymerization component include aromatic dicarboxylic acids such as isophthalic acid, (anhydrous) phthalic acid, 2,6-naphthalenedicarboxylic acid, and 5-sodium sulfoisophthalic acid, oxalic acid, (anhydrous) succinic acid, and adipine. Acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dimer acid having 20 to 60 carbon atoms, (anhydrous) maleic acid, fumaric acid, (anhydrous)
Aliphatic dicarboxylic acids such as itaconic acid, (anhydrous) citraconic acid and mesaconic acid, alicyclic dicarboxylic acids such as (anhydrous) hexahydrophthalic acid and hexahydroterephthalic acid, p-
Hydroxybenzoic acid, lactic acid, β-hydroxybutyric acid, ε-
Hydroxycarboxylic acid such as caprolactone, (anhydrous)
Examples thereof include polyfunctional carboxylic acids such as trimellitic acid, trimesic acid and (anhydrous) pyromellitic acid. Also,
Examples of the alcohol component as a copolymerization component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol. , Aliphatic diols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediethanol, ethylene oxide or propylene oxide adducts of bisphenol A and bisphenol S And other polyfunctional alcohols such as aromatic diols, trimethylolpropane, glycerin, pentaerythritol and the like. Especially, polytetramethylene glycol (PTMG) is used as an alcohol component.
Modified PBT copolymerized with 30 to 30% by mass, more preferably 5 to 20% by mass is particularly preferred for achieving the object of the present invention.

As a method for producing PBT or polyester mainly composed of PBT, a known method can be applied.
For example, dimethyl terephthalate, 1,4-butanediol, and optionally other copolymerization components are charged into a transesterification reaction tank and reacted at a temperature of about 230 ° C. for several hours to obtain a transesterification reaction rate of about 95%. An esterified product is obtained. Then, this was transferred to a polymerization vessel and tetra-n-
If necessary, other copolymerization components are added in the presence of a catalyst such as butyl titanate, and the melt weight is reduced under reduced pressure of 1.3 hPa or less and at a temperature of 210 to 250 ° C. until a polyester having a desired viscosity is obtained. The condensation reaction may proceed. Also,
Further, a solid phase polymerization reaction may be carried out.

The multilayer stretched polyamide film of the present invention has at least one of its constituent layers as the above resin layer (X).
As a practical configuration, for example, a configuration having at least two layers of a resin layer (X) and a resin layer (Y) composed of an aliphatic polyamide (B), a resin layer (X) and a polyamide ( A structure having at least two resin layers (W) made of a mixture of A) and an aliphatic polyamide (B), and a more practical structure is a polyamide in the middle of the resin layers (X) and (Y). At least 3 consisting of (A) and / or X / Z / Y having a resin layer (Z) in which the amorphous polyamide (C) and the polyamide (B) are mixed
It is a structure having layers. Among these layer constitutions, excellent delamination strength, strength, gas barrier property, dimensional stability,
Examples of the most practical layer structure having excellent performance such as retort resistance include a 5-layer structure of Y / Z / X / Z / Y.

In the present invention, the aliphatic polyamide (B) used in the resin layer (Y) of the multilayer stretched polyamide film is nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 1
2, nylon 11, and copolyamides and mixed polyamide resins of these, and nylon 6 is particularly preferable. The resin layer (Y) may be mixed with a small amount of another polyamide such as polyamide (A) by mixing a recycled product or the like, as long as the characteristics of the multilayer stretched polyamide film of the present invention are not impaired.

In the present invention, the amorphous polyamide (C) used for the resin layer (Z) of the multilayer stretched polyamide film is a generic term for those having no crystallinity or those having poor crystallinity, and there is no particular limitation. However, it is generally a polymer containing a monomer component having a structure that inhibits crystallization, that is, a side chain or a ring structure. Examples of such a polymer include dicarboxylic acids such as terephthalic acid and isophthalic acid, hexamethylenediamine, 4,4′-diamino-3,3′-dimethyl-dicyclohexylenemethane,
Polyamide obtained by reaction with diamine such as 4,4′-diamino-dicyclohexylenepropane or isophoronediamine, or copolymerization of the above components with an isocyanate component such as lactam component or 4,4′-diphenylmethane-diisocyanate. Examples include polyamides.

In the present invention, the mixing ratio of the polyamide (A) and / or the amorphous polyamide (C) and the polyamide (B) used in the resin layer (Z) of the multilayer stretched polyamide film is polyamide (A). And / or the proportion of the polyamide (B) in the range of 50 to 20 mass% with respect to the amorphous polyamide (C) in the range of 50 to 80 mass% is preferable in order to enhance the delamination strength. When the polyamide (A) and the amorphous polyamide (C) are mixed, a sufficient delamination strength can be obtained at any mixing ratio. In addition, the resin layer (Z)
As the above, by performing multi-layer coextrusion using a resin in which polyamide (A) and / or (C) and (B) are melt-mixed in advance, the delamination strength between the resin layers is further improved.
As conditions for melt-mixing the polyamide (A) and / or (C) and (B), a twin screw extruder is used and a temperature of 25
It is preferable to extrude in the range of 0 to 300 ° C. If the temperature is less than 250 ° C, the effect of improving the delamination strength is insufficient, and if it exceeds 300 ° C,
The penetration of the resin into the extruder becomes poor.

Further, talc is added to the resin layer (X) in an amount of 0.01 to
By adding 0.5% by mass, the strength of the obtained multilayer stretched polyamide film can be improved. When the amount of talc to be blended is less than 0.01% by mass, the effect of improving strength is not exhibited, and even when added in an amount of more than 0.5% by mass, the effect of improving strength is saturated and the haze of the film is rather deteriorated. Not preferable.

The multilayer stretched polyamide film of the present invention comprises
Tensile strength 200-350 MPa, Tensile elongation 80-130
% (Average value of MD and TD), number of pinholes generated is 5 or less, hot water shrinkage rate is 0.5 to 4%, haze is 8% or less, 20
Oxygen transmission rate at 100 ℃ / (m)
² · d · MPa) or less and delamination strength of 3N / 15 mm or more. The tensile strength and the hot water shrinkage ratio are both average values in the machine direction (MD) of the film and the perpendicular direction (TD) thereof.

If the tensile strength is less than 200 MPa, the strength of the packaging bag is insufficient, and if the tensile strength exceeds 350 MPa, not only is the quality excessive, but the operability during film production is rather deteriorated, which is economically undesirable. If the number of pinholes generated exceeds 5, the strength of the packaging bag is insufficient, which is not preferable. If the hot water shrinkage exceeds 4%, problems such as curling occur in the process of manufacturing the packaging bag, and 0.5
If it is less than%, not only is the quality excessive, but the operability at the time of film production is rather lowered, which is not preferable. If the haze exceeds 8%, the commercial value of the packaging bag is reduced, which is not preferable, and the oxygen permeability is 100 ml / (m ² · d).
If it is larger than (MPa), the performance required for long-term storage of the content becomes insufficient.

In order to enhance the practical performance when used as a packaging bag, the higher the delamination strength is, the more preferable. However, the multilayer stretched polyamide film of the present invention has a practical practical performance of 3 N / 15 mm or more.

As the method for producing the multilayer polyamide film in the present invention, any known method can be adopted. That is, each resin constituting each layer is melted by using a different extruder, and is extruded from a die after being superposed by a feed block method, and a method of extruding several kinds of molten resins superposed in a multi-manifold die. It is possible to adopt a method of laminating each resin layer by lamination, a method of combining these, and the like.

The stretching method for the multilayer film is as follows:
A method such as a flat type sequential biaxial stretching method, a flat type simultaneous biaxial stretching method, or a tubular method can be used,
The flat simultaneous biaxial stretching method is most preferable in order to obtain the uniform thickness of the multilayer film and the uniform physical properties in the longitudinal and transverse directions.

Next, the manufacturing method by the flat simultaneous biaxial stretching method will be described. For example, first, a composition comprising nylon 6 from the extruder (a), MXD6 and PBT from the extruder (b) or a polyester containing them as the main component, and optionally talc, using a 3 type 5 layer coextrusion T-die. The composition comprising nylon 6 and MXD6 is extruded from the extruder (c) in the temperature range of 230 to 280 ° C. to extrude the multilayer unstretched sheet, and is brought into close contact with a cooling drum whose temperature is adjusted to room temperature or lower to be rapidly cooled.

Next, the obtained sheet is passed through a hot water bath controlled at 40 to 70 ° C. to adjust the water content to 3 to 7%, preheated to 140 to 210 ° C., and then 160 to 210 ° C. 22
Simultaneously biaxially stretching at a stretching ratio of 2 to 4 times in the longitudinal and transverse directions at 0 ° C., and then performing a relaxation treatment of 1 to 5% in the transverse direction, and then 150 to 2
By heat-treating at 20 ° C. for several seconds, a multilayer stretched film having a desired thickness can be obtained.

When the temperature of the hot water bath is lower than 40 ° C., it is not economical because the impregnation time required for the unstretched multilayer sheet to have a constant water content is long, and when it is higher than 70 ° C., the sheet is deformed during impregnation. To do. Also, even if the water content is lower than 3%,
Even if it is higher than 7%, the stretchability is lowered. Further, if the preheating temperature and the stretching temperature are out of the above-mentioned ranges, uneven stretching may occur or the film may break during stretching, which is not preferable.

When the multilayer stretched film of the present invention is used as a packaging bag, it is usually provided with heat sealability, and in order to further enhance gas barrier properties and mechanical strength depending on the application, polypropylene, polyethylene, It is used by laminating it with an ethylene-vinyl acetate copolymer, a plastic film such as polyester, paper, or a metal foil such as aluminum.

The thickness of the multilayer stretched film in the present invention is not particularly limited, but when it is used as a flexible packaging material, a thickness of 300 μm or less, usually 5 to 50 μm is used.

In order to improve the productivity of the film, usually, an inorganic lubricant such as silica, alumina, kaolin, calcium carbonate or an organic lubricant such as ethylenebisstearylamide can be added to improve the slip property of the film surface. .

[0031]

EXAMPLES Next, the present invention will be described more specifically by way of examples. The raw materials and measuring methods used for the evaluation of the examples and comparative examples are as follows.

1. Raw material (1) Nylon 6 (N6); Unitika A1030B
RF (2) MXD6; Mitsubishi Gas Chemical Co., Ltd. MX nylon 600
7 (relative viscosity 2.64) (3) PBT-1; 194 parts of dimethyl terephthalate,
Add 108 parts of 1,4-butanediol and 80 ppm of tetrabutyl titanate (value converted to the weight of titanium metal to the polymer), and add 2.5 at 150-210 ° C.
The transesterification reaction was carried out for an hour. The obtained transesterification reaction product was transferred to a polymerization vessel to start depressurization, and finally under reduced pressure of 4 hPa, melt polymerization was performed at a temperature of 210 to 245 ° C. for 2 hours to obtain PBT-1. (4) PBT-2; dimethyl terephthalate 194 parts,
Add 108 parts of 1,4-butanediol and 80 ppm of tetrabutyl titanate (value converted to the weight of titanium metal to the polymer), and add 2.5 at 150-210 ° C.
The transesterification reaction was carried out for an hour. The obtained transesterification reaction product was transferred to a polymerization vessel, and after adding 40 ppm of tetrabutyl titanate, 15% by mass of polytetramethylene glycol (PTMG) having a molecular weight of 1100 was added to start depressurization and finally 4 hPa. Under reduced pressure, temperature 210
PBT-2 was obtained by melt polymerization at ˜245 ° C. for 2 hours. (5) Talc (TL); UPNHS-T0.
5 (6) Amorphous polyamide (AN); Grivory G21 manufactured by EMS (copolymer of hexamethylenediamine and terephthalic acid and isophthalic acid)

2. Measurement method (1) ASTM-D using a sample with tensile strength, elongation width of 10 mm and length of 10 cm
It was measured according to 882. (2) Hot water shrinkage rate A sample having a width of 10 mm and a length of 10 cm was immersed in boiling water for 30 minutes, the dimensional change before and after the treatment was measured, and the percentage to the original length was obtained. (3) Haze Tokyo Denshoku fully automatic haze meter (TC-H3DPK)
Was measured according to JIS K-6714. Haze (%) = [Td (diffuse transmittance%) / Tt (total light transmittance%)] × 100 (4) Pinhole resistance Fed. Test M
method Std. 101C Method201
12 inch x 8 inch sample according to 7.
It has a 5 inch cylindrical shape, grips both ends, and has an initial gripping interval of 7
The number of pinholes generated after bending 1000 times at 5 ° C. was measured by a so-called gel bot tester (manufactured by Rigaku Kogyo Co., Ltd.) at a speed of 40 times / min. . (5) Oxygen permeability OX-TRAN1 manufactured by Modern Control Co.
The measurement was performed using 0-50A under the conditions of 20 ° C. and 85% RH. (Unit: ml / (m ² · d · MPa)) (6) Delamination strength After peeling the edge of the multilayer film with a width of 15 mm at the interface, 2
The peel strength was measured by a T peel method at a peel rate of 300 mm / min in an atmosphere of 0 ° C. and 65% RH using an autograph manufactured by Shimadzu Corporation. (7) Moisture content About 20 g is collected from a non-stretched multilayer sheet impregnated in a hot water bath into a weighing bottle and precisely weighed. Then, 2 in a constant temperature dryer at 120 ± 2 ℃.
After drying for an hour, the mixture was slowly cooled to room temperature in a calcium chloride desiccator, and the weight was precisely weighed to determine the weight loss rate (%). (8) A hot-water treatment-resistant multilayer stretched film was applied to an unstretched polypropylene (Toray's Trefan ZK-93K, 6 by a dry lamination method).
(0 μm) was laminated and heat sealed on three sides to produce a rectangular filling bag having a length of 14 cm and a width of 12 cm. Next, after filling 50 ml of water into this bag and heat-sealing the other side, the appearance of the bag after being subjected to hot water treatment at 120 ° C. for 30 minutes was visually observed, and the appearance was checked according to the following criteria. It was evaluated in three stages. A: Good B: A small part (5% or less of the surface area of the filling bag) has a poor appearance. C: Partial (5% or more of the surface area of the filling bag) or the entire surface is defective in appearance.

Example 1 Using a twin-screw extruder PCM45 manufactured by Ikegai Co., a mixture of 30 parts by mass of N6 and 70 parts by mass of MXD6 was melt extruded at an extrusion temperature of 300 ° C. and then pelletized. The obtained pellets were dried at 140 ° C. for about 2 hours for crystallization. Using a three-kind five-layer coextrusion T-die, N6 at a temperature of 250 ° C. from the extruder (a) (Y layer) and MX from the extruder (b).
MXD6 / PBT-2 = 95/5 for D6 and PBT-2
0.2% by mass of talc in resin mixed at a ratio of (mass%)
Was mixed at a temperature of 265 ° C. (X layer), and N6 and MXD6 were mixed with N6 / MXD6 = 30/7 from the extruder (C).
A resin mixed at a ratio of 0 (mass%) was melt extruded at a temperature of 280 ° C. (Z layer), and a sheet laminated in the order of Y / Z / X / Z / Y was extruded from a die to obtain a surface temperature of 1
The layer was made to have a thickness of Y / Z / X / Z / Y = 45/5/50/5/4 by bringing it into close contact with a cooling drum whose temperature was adjusted to 8 ° C. and rapidly cooling.
5 (μm), an unstretched multilayer sheet having a total thickness of 150 μm was obtained. The obtained sheet was sent to a warm water tank whose temperature was controlled at 60 ° C., and subjected to a water immersion treatment for 1.5 minutes to adjust the water content to 4.7%. The edges of this sheet are gripped with clips of a tenter type simultaneous biaxial stretching machine and preheated at 175 ° C, and then the simultaneous biaxial stretching is performed with a stretching temperature of 190 ° C, a stretching ratio of 3.0 times the length and 3.3 times the width. Then, the relaxation rate in the lateral direction is set to 5%, and 2
After heat treatment at 10 ° C for 4 seconds, the film is cooled and wound, and the thickness of each layer is Y / Z / X / Z / Y.
= 4.5 / 0.5 / 5.0 / 0.5 / 4.5 (μm) and a multilayer stretched film having a thickness of 15 μm was obtained. Next, the obtained raw fabric roll was slit, and various film performances were evaluated. The results are shown in Table 1. As shown in Table 1, the number of pinholes generated was small, the transparency and the oxygen barrier property were good, and the film was suitable as a packaging film.

Examples 2 to 4 and Comparative Examples 1 to 7 Table 1 shows the types and blending amounts of PBT added to the X layer, and the blending amounts of polyamides (A), (B) and (C) used in the Z layer. A multilayer stretched film was produced in the same manner as in Example 1 except that the changes were made as shown in FIG. The results of measuring various film performances are shown in Table 1.

[0036]

[Table 1]

[0037]

EFFECT OF THE INVENTION The multilayer stretched polyamide film of the present invention has excellent transparency, tensile strength, delamination strength, gas barrier property and dimensional stability, and is a film suitable for packaging which is excellent in retort resistance. It is provided and its industrial utility value is extremely high.

Continuation of the front page (56) Reference JP-A-7-16943 (JP, A) JP-A-11-246686 (JP, A) JP-A-8-156205 (JP, A) JP-A-2000-233442 (JP, A) JP 2001-138459 (JP, A) JP 58-197050 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00 -35/00 C08L 77 / 00-77/12 C08J 5/18

Claims (6)

(57) [Claims] 1. A polyamide (A) mainly composed of a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms in at least one layer in an amount of 99 to 75% by mass, and polybutylene terephthalate or the same. Is a multilayer stretched polyamide film having a resin layer (X) composed mainly of 1 to 25% by mass of polyester.
The polyester is used as a diol component
Modified polybutylene copolymer copolymerized with ramethylene glycol
A multilayer stretched polyamide film that is a phthalate . 2. The multilayer stretched polyamide film according to claim 1, which has at least two layers of a resin layer (X) and a resin layer (Y) composed of an aliphatic polyamide (B). 3. An intermediate layer between the resin layer (X) and the resin layer (Y),
Polyamide (A) and / or amorphous polyamide (C) is 50 to 80% by mass, and polyamide (B) is 50
The multilayer stretched polyamide film according to claim 2 , comprising at least three layers, each having a polyamide resin layer (Z) in a proportion of -20% by mass. 4. Talc in the resin layer (X) in an amount of 0.01-0.
The multilayer stretched polyamide film according to any one of claims 1 to 3 containing 5 wt%. 5. The multilayer stretched film is Y / Z / X / Z /
The multilayer stretched polyamide film according to claim 3, comprising 5 layers of Y. 6. The oxygen permeability is 100 ml / (m ² · d ·).
The multilayer stretched polyamide film according to any one of claims. 1 to 5 MPa) less.