JP2006192592A - Polyamide multilayered film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide multilayered film having high surface lubricity and excellent pinhole resistance, and its manufacturing method. <P>SOLUTION: The polyamide multilayered film comprises a polyamide layer containing a lubricant, a polyamide layer containing a softener, and a gas barrier layer, wherein the polyamide layer containing the lubricant is the outermost layer. This polyamide multilayered film is characterized in that (a) the coefficient of dynamic friction (25°C×80% RH) of the surfaces of the mutual outermost layers of the polyamide multilayered films according to ASTM D-1894 is 0.40 or below and (b) the number of pinholes produced in a Gerboflex test of 5°C×1,000 times is 8/300 or below. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyamide-based multilayer film used for packaging food or the like.

  Polyamide-based films are excellent in gas barrier properties, strength, and the like, and are therefore widely used for food packaging and the like mainly for the purpose of protecting contents (Patent Documents 1, 2, etc.).

  However, since the polyamide-based film easily absorbs moisture, there is a drawback that the slipperiness of the film surface tends to be deteriorated. For example, when filling water-based foods such as soups and strawberries into a polyamide film for packaging using an automatic filling machine, the working environment becomes humid, so the polyamide film absorbs moisture and mechanical suitability is poor. Therefore, the food filling process often stops. This reduces the work efficiency of food packaging.

  In addition, recently, there is a strong intention of users who want to reduce the frequency of accidents to zero as much as possible in the course of distribution, etc. for the polyamide film for packaging of the above-mentioned water-based foods, and further attempts to impart pinhole resistance Has been made. In order to improve this pinhole resistance, modifiers such as olefins and polyamide elastomers are blended, but on the contrary, this may promote moisture absorption of the film and further deteriorate the slipperiness.

Therefore, a polyamide-based film having high film surface lubricity and excellent pinhole resistance even under high humidity is desired.
JP-A-62-115029 JP 62-1331060 A

  The main object of the present invention is to provide a polyamide-based multilayer film having high film surface lubricity and excellent pinhole resistance and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventor has a polyamide layer containing a lubricant, a polyamide layer containing a softening agent, and a gas barrier layer, and the polyamide layer containing the lubricant becomes the outermost layer. It has been found that the polyamide-based multilayer film has high film surface lubricity and excellent pinhole resistance. Based on this knowledge, the present invention was completed by further research.

  That is, this invention provides the following polyamide-type multilayer film and its manufacturing method.

Item 1. A polyamide-based multilayer film comprising a polyamide layer containing a lubricant, a polyamide layer containing a softening agent, and a gas barrier layer, wherein the polyamide layer containing the lubricant is an outermost layer;
(A) The coefficient of dynamic friction (25 ° C x 80% RH) between the outermost surfaces of a polyamide-based multilayer film according to ASTM D-1894 is 0.40 or less, and (b) 5 ° C x 1,000 gelbo flex tests The polyamide-based multilayer film is characterized in that the number of pinholes generated in is 8 pieces / 300 cm ² or less.

  Item 2. Item 2. The polyamide-based multilayer film according to Item 1, wherein the lubricant is inorganic filler particles and / or a bisamide compound.

  Item 3. Item 3. The lubricant is inorganic filler particles and a bisamide compound, and the amount of inorganic filler particles is 0.05 to 0.5 parts by weight and the amount of bisamide compound is 0.05 to 0.5 parts by weight with respect to 100 parts by weight of polyamide. Polyamide-based multilayer film.

  Item 4. Item 4. The polyamide multilayer film according to Item 1, 2, or 3, wherein the softening agent is a modified ethylene-vinyl acetate copolymer and / or an ethylene-methacrylic acid copolymer ionomer.

  Item 5. The softening agent is a modified ethylene-vinyl acetate copolymer and an ethylene-methacrylic acid copolymer ionomer. The blending amount of the modified ethylene-vinyl acetate copolymer is 0.5 to 10.0 parts by weight with respect to 100 parts by weight of the polyamide, and ethylene. -Polyamide type multilayer film of claim | item 4 whose compounding quantity of methacrylic acid copolymerization ionomer is 0.1-5.0 weight part.

  Item 6. Item 6. The polyamide multilayer film according to any one of Items 1 to 5, wherein the gas barrier layer is EVOH or aromatic polyamide.

Item 7. The polyamide-based multilayer film according to any one of Items 1 to 6 having the following layer structure:
A1 / B1 / C1,
A1 / B1 / C1 / A2,
A1 / B1 / C1 / B2,
A1 / B1 / C1 / B2 / A2,
A1 / B1 / C1 / A2 / B2,
A1 / C1 / B1,
A1 / C1 / B1 / A2,
A1 / C1 / A2 / B1
(In the formula, A1 and A2 are the same or different and a polyamide layer containing a lubricant, B1 and B2 are the same or different and a polyamide layer containing a softening agent, C1 shows a gas barrier layer, and A1 shows an outermost layer).

  Item 8. Item 8. The polyamide multilayer film according to any one of Items 1 to 7, wherein the total thickness of the film is about 10 to 75 μm.

  Item 9. Item 8. The polyamide multilayer film according to Item 7, wherein the thickness of the polyamide layer A1 containing the lubricant as the outermost layer is about 6 to 30% with respect to the total thickness of the polyamide multilayer film.

  Item 10. Item 8. The polyamide multilayer film according to any one of Items 1 to 7, wherein the total thickness of the polyamide layer containing the softening agent is about 13 to 91% with respect to the total thickness of the polyamide multilayer film.

Item 11. Item 8. The polyamide-based multilayer film according to Item 7, having the following layer structure:
A1 / B1 / C1 / B2 / A2
(However, A1, A2, B1, B2, and C1 are the same as above).

  Item 12. Item 12. The polyamide-based multilayer film according to any one of Items 1 to 11, which is a biaxially stretched film.

  Item 13. A method for producing a polyamide-based multilayer film comprising a polyamide layer containing a lubricant, a polyamide layer containing a softening agent, and a gas barrier layer, wherein the polyamide layer containing the lubricant is an outermost layer, comprising a resin composition comprising a lubricant and a polyamide, A resin composition containing a softening agent and polyamide, and a resin composition having gas barrier properties are laminated by coextrusion so that the outermost layer becomes a polyamide layer containing a lubricant, stretched in two directions in the vertical and horizontal directions, and heat-treated. A method for producing a polyamide-based multilayer film.

  Item 14. Item 13. A food packaging film obtained by laminating a seal layer on a surface opposite to the outermost layer of the polyamide-based multilayer film according to any one of Items 1 to 12.

  Item 15. Item 15. A food packaging bag obtained by forming a bag shape with the outermost layer of the food packaging film of Item 14 facing outward and heat-sealing the sealing layer surfaces.

  Item 16. Item 16. A food package obtained by filling a food packaging bag according to Item 15.

The present invention is described in detail below.
I. Polyamide-based multilayer film The polyamide-based multilayer film of the present invention includes a polyamide layer containing a lubricant (hereinafter also referred to as “polyamide layer A”), a polyamide layer containing a softening agent (hereinafter also referred to as “polyamide layer B”), and The gas barrier layer C is included, and the polyamide layer A forms the outermost layer. (A) The dynamic friction coefficient (25 ° C. × 80% RH) between the outermost layer surfaces of the polyamide-based multilayer film according to ASTM D-1894 0.40 or less, and (b) the number of pinholes generated in a gelboflex test at 5 ° C. × 1,000 times is 8/300 cm ² or less.

Polyamide layer A
As a polyamide used for the polyamide layer A, an aliphatic polyamide is an essential component, and an aromatic polyamide, an amorphous polyamide, a polyamide elastomer, or the like may be contained as necessary.

  Examples of the aliphatic polyamide include aliphatic nylon and copolymers thereof. Specifically, polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecanamide (nylon-11), polylauryllactam ( Nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene Bacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,8) , Caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer Body (nylon-6 / 9), caprolactam / hexamethylenediammonium adipate copolymer (nylon-6 / 6,6), lauryllactam / hexamethylenediammonium adipate copolymer (nylon-12 / 6,6), Ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (nylon-2,6 / 6,6), caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6,6 / 6) 10), ethyleneammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6 / 6, 6/6, 10), etc., among which two or more fats Can be mixed with polyamid polyamide .

  The aliphatic polyamide is preferably nylon-6, nylon-6,6, more preferably nylon-6, nylon-6 / 6,6 (copolymer of nylon-6 and nylon-6,6), especially Nylon-6 is preferable.

  Examples of aromatic polyamides include aromatic diamines such as metaxylenediamine and paraxylenediamine, and dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid, or derivatives thereof. Examples thereof include crystalline aromatic polyamides obtained by polycondensation reaction. An aromatic nylon such as polymetaxylene adipamide (MXD-nylon) is preferable. Examples of the aromatic nylon include S-6007 and S-6011 (both manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  As an amorphous polyamide, the polyamide (6T-6I nylon) etc. which are obtained by isophthalic acid-terephthalic acid-hexamethylenediamine polycondensation reaction can be illustrated.

  Examples of polyamide elastomers include polyether ester amides.

  In the polyamide, the aliphatic polyamide is contained in an amount of about 50 to 100% by weight, preferably about 60 to 95% by weight, more preferably about 80 to 90% by weight. Further, the polyamide contains an aromatic polyamide and / or an amorphous polyamide and / or a polyamide elastomer of about 0 to 50% by weight, preferably about 5 to 40% by weight, more preferably about 10 to 20% by weight. is doing.

  The lubricant contained in the polyamide layer A is not particularly limited as long as it can reduce the dynamic friction coefficient on the surface of the outermost polyamide layer A, and examples thereof include inorganic filler particles and bisamide compounds. In the present invention, the polyamide layer A preferably contains both inorganic filler particles and a bisamide compound as a lubricant.

  Specific examples of the inorganic filler particles include silica-alumina clay minerals represented by clay, kaolin, calcined kaolin and the like; silica-magnesiums represented by talc; calcium silicate; silica; alumina; calcium carbonate and the like. It is done. The average particle diameter of the inorganic filler particles is about 0.5 to 6 μm, preferably about 2.0 to 5.0 μm. With such an average particle size, when the polyamide layer A becomes the outermost layer, excellent lubricity is imparted to the surface thereof.

  A widely known bisamide compound can be used as the bisamide compound. Specifically, the general formula (I) or (II);

（式中、Ｒ¹は２価の炭化水素残基、Ｒ²及びＲ³は同一又は異なって１価の炭化水素残基、Ｒ⁴及びＲ⁵は同一又は異なって水素原子又は１価の炭化水素残基、Ｒ⁶は２価の炭化水素残基、Ｒ⁷及びＲ⁹は同一又は異なって１価の炭化水素残基、Ｒ⁸及びＲ¹⁰は同一又は異なって水素原子又は１価の炭化水素残基を示す。）
で表されるビスアミド化合物が例示される。

(Wherein R ¹ is a divalent hydrocarbon residue, R ² and R ³ are the same or different and a monovalent hydrocarbon residue, R ⁴ and R ⁵ are the same or different and are a hydrogen atom or a monovalent carbon residue. Hydrogen residue, R ⁶ is a divalent hydrocarbon residue, R ⁷ and R ⁹ are the same or different and a monovalent hydrocarbon residue, R ⁸ and R ¹⁰ are the same or different and are a hydrogen atom or a monovalent carbon residue Indicates a hydrogen residue.)
The bisamide compound represented by these is illustrated.

In the bisamide compound represented by the general formula (I), examples of the divalent hydrocarbon residue represented by R ¹ include a divalent aliphatic hydrocarbon residue or an aromatic hydrocarbon residue. Examples of the divalent aliphatic hydrocarbon residue include alkylene groups such as ethylene, propylene, hexamethylene, octamethylene, and dodecamethylene. Examples of the divalent aromatic hydrocarbon residue include arylene groups such as phenylene, xylylene, naphthylene, and phenanthrylene.

Examples of the monovalent hydrocarbon residue represented by R ² or R ³ include monovalent aliphatic hydrocarbon residues (which may be partially unsaturated), preferably linear C5- 25 alkyl is mentioned. Specifically, it is obtained by removing carboxyl groups from fatty acids such as stearic acid, hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, arachidic acid, behenic acid, oleic acid, elaidic acid, and montanic acid. And a monovalent group.

The monovalent hydrocarbon residue represented by R ⁴ or R ⁵ includes a C 1-6 alkyl group, preferably a linear C 1-3 alkyl group such as methyl, ethyl, n-propyl and the like. R ⁴ and R ⁵ are preferably hydrogen atoms.

  Representative examples of the bisamide compounds represented by the general formula (I) include ethylene bis fatty acid amides such as ethylene bisstearyl amide and ethylene bisbehenyl amide.

  The bisamide compound represented by the general formula (I) can be easily produced by amidating the corresponding diamine and fatty acid.

In the bisamide compound represented by the general formula (II), the divalent hydrocarbon residue represented by R ⁶ includes two carboxyl groups from dicarboxylic acids such as terephthalic acid, p-phenylenedipropionic acid, succinic acid and adipic acid. Examples thereof include a divalent group obtained by removing the group.

Examples of the monovalent hydrocarbon residue represented by R ⁷ or R ⁹ include a monovalent aliphatic hydrocarbon residue or an aromatic hydrocarbon residue. Examples of the monovalent aliphatic hydrocarbon residue include C1-20 alkyl groups such as methyl, ethyl, butyl, hexyl, decyl, pentadecyl, octadecyl and dodecyl; C3-7 cycloalkyl groups such as cyclohexyl and the like. Examples of the monovalent aromatic hydrocarbon residue include aryl groups such as phenyl and naphthyl; and aralkyl groups such as benzylamine.

Examples of the monovalent hydrocarbon residue represented by R ⁸ or R ¹⁰ include a monovalent hydrocarbon residue represented by R ⁷ or R ⁹ . R ⁸ and R ¹⁰ are preferably a hydrogen atom.

  Among the bisamide compounds represented by the general formula (II), typical examples include dioctadecyl dicarboxylic acid amides such as dioctadecyl terephthalic acid amide.

  The bisamide compound represented by the general formula (II) can be easily produced by amidating the corresponding dicarboxylic acid and monoamine.

  The amount of lubricant blended in the polyamide layer A is about 0.05 to 2.0 parts by weight, preferably about 0.1 to 1.0 parts by weight, with respect to 100 parts by weight of polyamide. In particular, it is preferable to mix 0.05 to 0.5 parts by weight of inorganic filler particles and 0.05 to 0.5 parts by weight of a bisamide compound with respect to 100 parts by weight of polyamide.

  In addition, you may surface-treat the surface of the polyamide layer A which is the outermost layer, such as a silane coupling agent. Thereby, in a film manufacturing process, there exists an effect which suppresses generation | occurrence | production of the foreign material (Meyan) adhering to a die slip port.

  The polyamide layer A may further contain other components such as polymethyl methacrylate having an anti-blocking effect as long as the effects of the present invention are not adversely affected. When the polyamide layer A contains other components, the content of these components is usually 0.5 parts by weight or less, preferably about 0.02 to 0.2 parts by weight, based on 100 parts by weight of the polyamide.

Polyamide layer B
As a polyamide used for the polyamide layer B, an aliphatic polyamide is an essential component, and an aromatic polyamide, an amorphous polyamide, a polyamide elastomer, or the like may be contained as necessary. Specifically, the polyamide exemplified in the polyamide layer A is preferably used. In addition, although the kind and compounding ratio of the polyamide contained in the polyamide layer B may be the same as or different from the polyamide layer A, both use the same polyamide from the point of simplicity of multilayer film production. Is preferred.

The softener contained in the polyamide layer B is not particularly limited as long as it is used for improving the pinhole resistance of the multilayer film. Specific examples of the softening agent include a modified ethylene-vinyl acetate copolymer and an ethylene-methacrylic acid copolymer ionomer. Here, the modified ethylene-vinyl acetate copolymer includes (1) a resin in which -OCOCH ₃ is partially saponified, (2) a resin in which -OCOCH ₃ is partially substituted with -OCOCH ₂ CH ₃ , (3 ) Resins obtained by partially graft polymerization of acid anhydrides such as maleic anhydride.

  The amount of the softening agent blended in the polyamide layer B is about 0.6 to 15 parts by weight, preferably about 1.5 to 10 parts by weight, and particularly about 2.0 to 8.0 parts by weight with respect to 100 parts by weight of the polyamide. Among them, with respect to 100 parts by weight of polyamide, 0.5 to 10.0 parts by weight (especially 2.5 to 6.0 parts by weight) of modified ethylene-vinyl acetate copolymer and 0.1 to 5.0 parts by weight (particularly 0.3 to 5.0 parts by weight of ethylene-methacrylic acid copolymer ionomer). 2.0 parts by weight) is preferable.

  The polyamide layer B may further contain other components such as polymethyl methacrylate having an anti-blocking effect as long as the effects of the present invention are not adversely affected. When the polyamide layer B contains other components, the content of these components is usually 0.5 parts by weight or less, preferably about 0.02 to 0.2 parts by weight, based on 100 parts by weight of the polyamide.

Gas barrier layer C
Examples of the gas barrier layer C include EVOH and aromatic polyamide.

  EVOH is not particularly limited, but the ethylene content is 55 mol% or less (preferably 20 to 50 mol%, more preferably 29 to 44 mol%), and the saponification degree of the vinyl acetate component is 90 mol% or more (preferably 95 mol% or more) is preferably used.

  In addition, EVOH includes a small amount of an α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, etc .; an unsaturated carboxylic acid or a derivative thereof (in the range not adversely affecting the effects of the present invention). For example, it may contain a comonomer such as a salt, a partial alkyl ester, a complete alkyl ester, a nitrile, an amide, an anhydride); an unsaturated sulfonic acid or a salt thereof.

  The melt index (MI) of EVOH is preferably 0.5 to 50 g / 10 min (210 ° C., 2160 g load), more preferably 1 to 35 g / 10 min (same as above). If the MI is 0.5 g / 10 min (same as above) or higher, the melt extrusion is not hindered. On the other hand, if the MI is 50 g / 10 min (same as above) or less, the deterioration of the film forming property is suppressed. it can.

  Preferred EVOH includes, for example, SG464B, SG372B, DC3203FB, DT2903B (all manufactured by Nippon Synthetic Chemical Co., Ltd.).

  Examples of aromatic polyamides include polycondensation of aromatic diamines such as metaxylenediamine and paraxylenediamine with dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid, or derivatives thereof. Examples thereof include crystalline aromatic polyamides obtained by the reaction. An aromatic nylon such as polymetaxylene adipamide (MXD-nylon) is preferable. Examples of the aromatic nylon include S-6007 and S-6011 (both manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  The gas barrier layer C may further contain other components such as an aliphatic amide, a modified ethylene vinyl acetate copolymer, and a methacrylic acid copolymer ionomer as long as the effects of the present invention are not adversely affected. When the gas barrier layer C contains other components, the content of these components is usually 15 parts by weight or less, preferably about 1.0 to 7.5 parts by weight with respect to 100 parts by weight of EVOH or aromatic polyamide. .

Structure of polyamide-based multilayer film The polyamide-based multilayer film of the present invention includes a polyamide layer A, a polyamide layer B, and a gas barrier layer C, and the polyamide layer A forms the outermost layer. That is, it is a multilayer film composed of at least three layers having the polyamide layer A as the outermost layer.

  Specifically, the layer structure of the following multilayer film is illustrated.

A1 / B1 / C1,
A1 / B1 / C1 / A2,
A1 / B1 / C1 / B2,
A1 / B1 / C1 / B2 / A2,
A1 / B1 / C1 / A2 / B2,
A1 / C1 / B1,
A1 / C1 / B1 / A2,
A1 / C1 / A2 / B1
(In the formula, A1 and A2 are the same or different and a polyamide layer containing a lubricant, B1 and B2 are the same or different and a polyamide layer containing a softening agent, C1 shows a gas barrier layer, and A1 shows an outermost layer.)
The total thickness of the polyamide-based multilayer film of the present invention is about 10 to 75 μm, preferably about 12 to 40 μm. In such a range, the film productivity and the selling price are favorable, which is preferable.

  The thickness of the polyamide layer (for example, A1) containing the lubricant as the outermost layer is about 6 to 30%, preferably about 10 to 25% with respect to the total thickness of the polyamide-based multilayer film. Within such a range, the effect of improving the slipperiness of the film surface (reducing the dynamic friction coefficient) is exhibited even under conditions of high humidity.

  The total thickness (for example, B1 or B1 + B2) of the polyamide layer B containing the softening agent is about 13 to 91%, preferably about 20 to 85% with respect to the total thickness of the polyamide-based multilayer film. If it is this range, a softness | flexibility can be provided to a film and the product made from pinholes by bending can be improved.

  The total thickness of the gas barrier layer C is about 3 to 47% with respect to the total thickness of the polyamide-based multilayer film. If it is this range, desired gas-barrier property can be provided to a film.

  Further, it is preferable that the ratio (A1 / B) of the total thickness of the polyamide layer A1 containing the lubricant which is the outermost layer and the polyamide layer B containing the softening agent is 1/7 to 3/1.

  Among the above layer configurations, the layer configuration represented by A1 / B1 / C1 / B2 / A2 is preferable. In addition, from the viewpoints of simplicity of the mold for film production, productivity, and the like, it is preferable that A1 and A2 have the same composition and B1 and B2 have the same composition.

  Also in this case, the total thickness of the polyamide-based multilayer film is preferably about 10 to 75 μm.

In addition, you may surface-treat the surface of the polyamide layer A which is the outermost layer, such as a silane coupling agent. Thereby, there exists an effect which suppresses generation | occurrence | production of the foreign material (Meani) adhering to a die slip opening | mouth in a film manufacturing process.
II. Manufacture of a polyamide-based multilayer film The polyamide-based multilayer film of the present invention is formed by coextruding a resin on each layer on a chill roll in which cooling water circulates from a T die so that a polyamide layer containing a lubricant is present in the outermost layer. A multilayer film is obtained. The obtained film is stretched longitudinally 2 to 4 times by, for example, a roll stretching machine at 50 to 100 ° C., and further stretched 2 to 5 times by a tenter stretching machine in an atmosphere at 90 to 150 ° C. Can be obtained by heat treatment in an atmosphere of 100 to 240 ° C. The multilayer film of the present invention may be uniaxially stretched or biaxially stretched (simultaneous biaxial stretching, sequential biaxial stretching), and the obtained multilayer film may be subjected to corona discharge treatment on both surfaces or one surface if necessary. It can also be applied.
III. Features of the polyamide-based multilayer film The polyamide-based multilayer film of the present invention produced as described above has not only gas barrier properties but also high film surface slipperiness even under high humidity conditions, and resistance to pinholes caused by bending. It has the feature of being excellent.

  Specifically, the dynamic friction coefficient (25 ° C. × 80% RH) between the outermost surfaces of the polyamide-based multilayer film according to ASTM D-1894 is 0.40 or less, further 0.37 or less, particularly about 0.25 to 0.35. Have. The evaluation of lubricity (dynamic friction coefficient) is as described in Test Example 1.

In addition, the number of pinholes generated in the gelboflex test at 5 ° C x 1,000 times is 8 / 300cm ² or less, 6 / 300cm ² or less, especially 5 / 300cm ² or less. ing. Evaluation of pinholes by bending is as described in Test Example 1.

  Since the polyamide-based multilayer film of the present invention has the above characteristics, it is suitably used as a packaging film for water-based foods. Specifically, a film for food packaging is produced by laminating a seal layer on the surface opposite to the outermost layer (polyamide layer containing a lubricant) of the polyamide-based multilayer film. This is made into a bag shape with the outermost layer facing outward, and the seal layer surfaces are heat sealed to form a bag shape to produce a food packaging bag.

  Here, the sealing layer may be a resin film having heat sealing properties, and examples thereof include polyolefins such as LLDPE, LDPE, CPP, and EVA. As a method of laminating the polyamide-based multilayer film and the seal layer, a known method can be adopted. Also, a known method can be adopted as a heat sealing method.

  The obtained food packaging bag is filled with food to obtain a food package. The food to be packaged is not particularly limited, but the effects of the present invention are remarkably exhibited when packaging water-based foods such as soups and rice cakes.

  In addition to gas barrier properties, the polyamide-based multilayer film of the present invention has high film surface lubricity even under high humidity conditions, and is excellent in pinhole resistance due to bending. So far, there has been no report of a polyamide film having high film surface lubricity under high humidity conditions and excellent pinhole resistance, and this is achieved for the first time by the polyamide multilayer film of the present invention. Became possible.

  As a result, even when filling aquatic foods such as soup using an automatic filling machine, the food filling process will not be stopped due to the slipperiness of the film, and the work efficiency of food packaging will be greatly increased. It was to improve.

  In addition, since it has excellent pinhole resistance, it has become possible to reduce the frequency of accident occurrence in courses such as distribution.

  Next, the present invention will be described in more detail with reference to the following examples and comparative examples, but is not limited thereto.

Example 1
Nylon-6 (1022FD20, manufactured by Ube Industries; amorphous silica 3,600ppm, ethylenebisbehenylamide 1,600ppm, ethylenebisstearylamide 600ppm) 86 parts by weight, and aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 The resin composition which comprises a weight part and comprises a 1st layer and a 5th layer was manufactured.

  Also, nylon-6 81.7 parts by weight, aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 parts by weight, modified ethylene-vinyl acetate copolymer 3.7 parts by weight, and ethylene-methacrylic acid copolymer ionomer 0.6 parts by weight The resin composition which comprises a 2nd layer and a 4th layer was mix | blended.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 15 μm was obtained. The thickness of each layer was 3/3/3/3/3 (μm).

Example 2
Nylon-6 (1022FD20, manufactured by Ube Industries; 80 parts by weight of amorphous silica 3,600ppm, ethylenebisbehenylamide 1,600ppm, ethylenebisstearylamide 600ppm), and amorphous nylon (X-21; manufactured by Mitsubishi Engineering Plastics) 20 weights The resin composition which comprises a part and comprises a 1st layer and a 5th layer was manufactured.

  Further, 80 parts by weight of nylon-6, 20 parts by weight of amorphous nylon, 3.7 parts by weight of a modified ethylene-vinyl acetate copolymer, and 0.6 parts by weight of an ethylene-methacrylic acid copolymer ionomer are blended, and the second layer and the fourth layer. A resin composition constituting the layer was produced.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 20 μm was obtained. The thickness of each layer was 4 / 4.5 / 3 / 4.5 / 4 (μm).

Comparative Example 1
Nylon-6 (1022FD20, manufactured by Ube Industries; amorphous silica 3,600ppm, ethylenebisbehenylamide 1,600ppm, ethylenebisstearylamide 600ppm) 86 parts by weight, aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 weights Part, 3.7 parts by weight of modified ethylene-vinyl acetate copolymer, and 0.6 parts by weight of ethylene-methacrylic acid copolymer ionomer were blended to produce a resin composition constituting the first layer and the fifth layer.

  Also, nylon-6 81.7 parts by weight, aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 parts by weight, modified ethylene-vinyl acetate copolymer 3.7 parts by weight, and ethylene-methacrylic acid copolymer ionomer 0.6 parts by weight The resin composition which comprises a 2nd layer and a 4th layer was mix | blended.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 20 μm was obtained. The thickness of each layer was 4 / 4.5 / 3 / 4.5 / 4 (μm).

Comparative Example 2
Nylon-6 (1022FD20, manufactured by Ube Industries; amorphous silica 3,600ppm, ethylenebisbehenylamide 1,600ppm, ethylenebisstearylamide 600ppm) 80 parts by weight, amorphous nylon (X-21; manufactured by Mitsubishi Engineering Plastics) 20 parts by weight Then, 3.7 parts by weight of a modified ethylene-vinyl acetate copolymer and 0.6 parts by weight of an ethylene-methacrylic acid copolymer ionomer were blended to produce a resin composition constituting the first layer and the fifth layer.

  Also, 80 parts by weight of nylon-6, 20 parts by weight of amorphous nylon (X-21; manufactured by Mitsubishi Engineering Plastics), 3.7 parts by weight of modified ethylene-vinyl acetate copolymer, and 0.6 parts by weight of ethylene-methacrylic acid copolymer ionomer The resin composition which comprises a 2nd layer and a 4th layer was mix | blended.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 20 μm was obtained. The thickness of each layer was 4 / 4.5 / 3 / 4.5 / 4 (μm).

Comparative Example 3
Nylon-6 (1022FD20, manufactured by Ube Industries; amorphous silica 3,600ppm, ethylenebisbehenylamide 1,600ppm, ethylenebisstearylamide 600ppm) 86 parts by weight, and aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 The resin composition which comprises a weight part and comprises a 1st layer and a 5th layer was manufactured.

  In addition, 81.7 parts by weight of nylon-6 and 14 parts by weight of aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) were blended to produce a resin composition constituting the second layer and the fourth layer.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 15 μm was obtained. The thickness of each layer was 3/3/3/3/3 (μm).

Comparative Example 4
The resin composition which comprises a 1st layer-a 5th layer with the raw material mixing | blending similar to Example 1 was manufactured.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 15 μm was obtained. The thickness of each layer was 0.5 / 5.5 / 3 / 5.5 / 0.5 (μm).

Comparative Example 5
The resin composition which comprises a 1st layer-a 5th layer with the raw material mixing | blending similar to Example 1 was manufactured.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 15 μm was obtained. The thickness of each layer was 5/1/3/1/5 (μm).

Comparative Example 6
Nylon-6 (1022FD17, manufactured by Ube Industries; containing 2,000 ppm of amorphous silica and 300 ppm of ethylenebisstearate) and 86 parts by weight of aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) The resin composition which comprises the 1st layer and the 5th layer was manufactured.

  Also, nylon-6 81.7 parts by weight, aromatic nylon (S-6011; manufactured by Mitsubishi Gas Chemical) 14 parts by weight, modified ethylene-vinyl acetate copolymer 3.7 parts by weight, and ethylene-methacrylic acid copolymer ionomer 0.6 parts by weight The resin composition which comprises a 2nd layer and a 4th layer was mix | blended.

  Further, a saponified ethylene-vinyl acetate copolymer (DC3203FB, manufactured by Nippon Gosei Kagaku; ethylene content 32 mol%, saponification degree 99%) was used as a resin composition constituting the third layer.

  The resin composition constituting each layer is co-extruded on a chill roll in which cooling water circulates from a T die so that the order is the first layer / second layer / third layer / fourth layer / fifth layer. A flat five-layer film was obtained. This 5-layer film was longitudinally stretched 3.0 times by a roll stretching machine at 65 ° C., then stretched 4.0 times by a tenter stretching machine at 110 ° C. atmosphere, and further in an atmosphere at 210 ° C. by the same tenter. And a film having a thickness of 15 μm was obtained. The thickness of each layer was 3/3/3/3/3 (μm).

Test example 1
The polyamide multilayer films obtained in Examples 1 and 2 and Comparative Examples 1 to 6 were evaluated for lubricity and pinhole resistance. The measuring method is as follows.
[Evaluation of lubricity (dynamic friction coefficient)]
A sample for measuring lubricity (polyamide multilayer film) was dry-laminated on linear low density polyethylene (LLDPE, 50 μm, TUX-FCD manufactured by Tosero Co., Ltd.). With respect to the two obtained LLDPE laminated lyamide-based multilayer films, the lubricity (dynamic friction coefficient) between polyamide surfaces was measured according to ASTM D-1894. The measurement was performed under conditions of 25 ° C. × 80% RH. The dynamic friction coefficient was measured by performing the test three times, and the average value is shown in Table 1.
[Evaluation of pinhole by bending]
Evaluation of the pinhole property by bending was performed using a gelbo flex tester manufactured by RIKEN. In this method, a film formed into a cylindrical shape with a folding diameter of 150 mm and a length of 300 mm was attached to a gelboflex tester, and a linear horizontal motion of 62.5 cm at a twist angle of 440 ° was repeated 1000 times at 5 ° C. Then, the number of pinholes is examined using an osmotic solution. Note that the number of pinholes was measured at a location of 300 cm ^{2 in} the center portion of the sample that was twisted and bent. The number of pinholes was measured for three samples, and the average value is shown in Table 1.

表１の比較例１及び２より、最外層（第１層及び第５層）に滑剤と柔軟剤の両方を配合しても、動摩擦係数が大きくなり十分な滑性が得られなかった。

From Comparative Examples 1 and 2 in Table 1, even when both the lubricant and the softener were blended in the outermost layer (the first layer and the fifth layer), the dynamic friction coefficient was increased and sufficient lubricity was not obtained.

  From Comparative Example 3, if the softener was not blended in the second layer and the fourth layer, the pinhole resistance was extremely deteriorated.

  From Comparative Example 4, if the outermost layer was thin, sufficient lubricity could not be obtained.

  From Comparative Example 5, when the second layer and the fourth layer were thin, sufficient pinhole resistance could not be obtained.

  From Comparative Example 6, if the amount of lubricant such as amorphous silica or bisamide compound was small in the outermost layer, sufficient lubricity could not be obtained.

In contrast, the polyamide-based multilayer films of Examples 1 and 2 have a small coefficient of dynamic friction and a small number of pinholes due to bending. That is, it can be seen that it has excellent slipperiness even under humid conditions and has high pinhole resistance.

Claims (16)

A polyamide-based multilayer film comprising a polyamide layer containing a lubricant, a polyamide layer containing a softening agent, and a gas barrier layer, wherein the polyamide layer containing the lubricant is an outermost layer;
(A) The coefficient of dynamic friction (25 ° C x 80% RH) between the outermost surfaces of a polyamide-based multilayer film according to ASTM D-1894 is 0.40 or less, and (b) 5 ° C x 1,000 gelbo flex tests The polyamide-based multilayer film is characterized in that the number of pinholes generated in is 8 pieces / 300 cm ² or less. The polyamide-based multilayer film according to claim 1, wherein the lubricant is inorganic filler particles and / or a bisamide compound. The lubricant is inorganic filler particles and a bisamide compound, and the blending amount of the inorganic filler particles is 0.05 to 0.5 parts by weight and the blending amount of the bisamide compound is 0.05 to 0.5 parts by weight with respect to 100 parts by weight of the polyamide. The polyamide-based multilayer film described. The polyamide-based multilayer film according to claim 1, 2 or 3, wherein the softening agent is a modified ethylene-vinyl acetate copolymer and / or an ethylene-methacrylic acid copolymer ionomer. The softening agent is a modified ethylene-vinyl acetate copolymer and an ethylene-methacrylic acid copolymer ionomer. The blending amount of the modified ethylene-vinyl acetate copolymer is 0.5 to 10.0 parts by weight with respect to 100 parts by weight of the polyamide, and ethylene. The polyamide based multilayer film according to claim 4, wherein the blending amount of the methacrylic acid copolymerized ionomer is 0.1 to 5.0 parts by weight. The polyamide multilayer film according to any one of claims 1 to 5, wherein the gas barrier layer is EVOH or aromatic polyamide. The polyamide-based multilayer film according to any one of claims 1 to 6, which has the following layer structure:
A1 / B1 / C1,
A1 / B1 / C1 / A2,
A1 / B1 / C1 / B2,
A1 / B1 / C1 / B2 / A2,
A1 / B1 / C1 / A2 / B2,
A1 / C1 / B1,
A1 / C1 / B1 / A2,
A1 / C1 / A2 / B1
(In the formula, A1 and A2 are the same or different and a polyamide layer containing a lubricant, B1 and B2 are the same or different and a polyamide layer containing a softening agent, C1 shows a gas barrier layer, and A1 shows an outermost layer). The polyamide-based multilayer film according to any one of claims 1 to 7, wherein the total thickness of the film is about 10 to 75 µm. The polyamide multilayer film according to claim 7, wherein the thickness of the polyamide layer A1 containing the lubricant as the outermost layer is about 6 to 30% with respect to the total thickness of the polyamide multilayer film. The polyamide multilayer film according to any one of claims 1 to 7, wherein the total thickness of the polyamide layer containing the softening agent is about 13 to 91% with respect to the total thickness of the polyamide multilayer film. The polyamide-based multilayer film according to claim 7 having the following layer structure:
A1 / B1 / C1 / B2 / A2
(However, A1, A2, B1, B2, and C1 are the same as above). It is a biaxially stretched film, The polyamide-type multilayer film in any one of Claims 1-11. A method for producing a polyamide-based multilayer film comprising a polyamide layer containing a lubricant, a polyamide layer containing a softening agent, and a gas barrier layer, wherein the polyamide layer containing the lubricant is an outermost layer, and a resin composition comprising the lubricant and the polyamide, A resin composition containing a softening agent and polyamide, and a resin composition having gas barrier properties are laminated by coextrusion so that the outermost layer becomes a polyamide layer containing a lubricant, stretched biaxially and horizontally, and heat-treated. A method for producing a polyamide-based multilayer film. The film for food packaging formed by laminating | stacking a sealing layer on the surface on the opposite side to the outermost layer of the polyamide-type multilayer film in any one of Claims 1-12. The food packaging bag obtained by heat-sealing the sealing layer surfaces with the outermost layer of the food packaging film according to claim 14 facing the outside in a bag shape. A food package formed by filling a food packaging bag according to claim 15 with food.