JP3296102B2 - Gas barrier film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier film comprising a polyamide resin composition containing a specific layered phosphate, and more particularly to a film having excellent oxygen and water vapor barrier properties.

[0002]

2. Description of the Related Art In recent years, the demand for preservability of foods has become particularly high in recent years due to changes in lifestyles and the like. In particular, packaging of processed food products, such as processed meat products such as ham and bacon, requires long-term storage in a sterilized state by retort treatment or the like, and an oxygen barrier in the sense of preventing oxidation during storage at room temperature at room temperature. In addition to the properties, oxygen barrier properties under high humidity conditions such as retort treatment are required. Further, in order to prevent deterioration of food due to permeation of water vapor during retort treatment or storage at room temperature at room temperature, a water vapor barrier property is also required.

[0003] Polyamide resins are widely used as materials having excellent oxygen barrier properties under high humidity conditions. However, the oxygen barrier properties under relatively low humidity conditions such as storage at room temperature at room temperature are, for example, ethylene vinyl alcohol. Copolymer (E
VOH) was not always satisfactory. On the other hand, EVOH has drawbacks such as a sharp decrease in oxygen barrier properties under high humidity conditions and a tendency to form a gel during melt molding.

[0004] Japanese Patent Application Laid-Open No. 2-105856 and Japanese Patent Application Laid-Open No.
-80873 discloses a gas barrier film in which a layered silicate is uniformly dispersed in a polyamide resin. Although gas barrier properties are improved by these techniques, a new drawback is a significant increase in rigidity due to the reinforcing effect of the dispersed layered silicate, which makes the film harder, easier to handle during packaging, polyethylene, etc. However, there is a problem in that there is a problem in the adhesion at the time of heat sealing in the case of a laminated film with the above, or in the film toughness such as pinhole resistance.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film having excellent gas barrier properties and flexibility in a wide range of humidity.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is to provide a polyamide resin composition containing tetravalent cation layered phosphates. The gas barrier film is characterized in that at least 50% of the layered phosphates of the cations have an interlayer distance of at least 15 angstroms in the polyamide resin composition.

Hereinafter, the present invention will be described in detail. The polyamide resin in the polyamide resin composition used in the present invention includes an amide bond (—NHCO—) in the main chain.
And a polymer that can be heated and melted. Preferred aliphatic polyamide resins include polytetramethylene adipamide (nylon 46), polycaprolactam (nylon 6), polyhexamethylene adipamide (nylon 66), and copolymers containing dimerized fatty acids as copolymer components. Polyamide, polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecanolactam (nylon 11), polydodecanolactam (nylon 12) and the like. Suitable aromatic polyamide resins include polyamides obtained from terephthalic acid and / or isophthalic acid and hexamethylenediamine, polyamides obtained from adipic acid and meta-xylylenediamine, terephthalic acid and / or isophthalic acid, adipic acid and hexane. Examples thereof include polyamides obtained from methylene diamine, polyamides obtained from terephthalic acid and / or isophthalic acid, adipic acid and meta-xylylenediamine, and copolymerized polyamides containing 1,3-phenylenedioxane acetic acid as a copolymerization component. These may be used as a mixture of a plurality of types.

The raw materials for such polyamide resins are diamines and dicarboxylic acids, lactams or polymerizable ω-amino acids, salts composed of diamines and dicarboxylic acids, and oligomers of these raw materials. Specific examples of such polyamide raw materials are described in JP-A-3-177425 and Japanese Patent Application No. 5-245.
199, etc., as diamines, aliphatic diamines such as tetramethylenediamine and hexamethylenediamine, xylylenediamines and the like, and dicarboxylic acids such as adipic acid and sebacic acid. Aromatic dicarboxylic acids such as aromatic dicarboxylic acids, terephthalic acid and isophthalic acid, iminodiacetic acid, oxydiacetic acid,
Dicarboxylic acids having an aromatic ring, such as 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, thiodiacetic acid, and 2,6-naphthalenedioxydiacetic acid, dimerized fatty acids, and the like. , Lactams such as caprolactam, undecanolactam, dodecanolactam and the like, and polymerizable ω-amino acids as 6-aminocaproic acid;
Representative examples include 11-aminoundecanoic acid and 12-aminododecanoic acid. These various polyamide resins or polyamide raw materials may be used in combination of several kinds. The molecular weight of these polyamide resins is not particularly limited, but is usually preferably used in the range of a number-average polymerization degree of 70 to 600, and is preferably 100 in terms of toughness and moldability.
More preferably, it is in the range of 400 to 400.

Among these polyamides, aliphatic polyamides such as nylon 6 and nylon 66 are particularly suitable for the present invention because of their balance between gas barrier properties and mechanical properties.
Alternatively, a polyamide obtained from terephthalic acid and / or isophthalic acid and hexamethylenediamine, a polyamide obtained from adipic acid and metaxylylenediamine, a polyamide obtained from terephthalic acid and adipic acid and hexamethylenediamine, a copolymer component 1, 3 as
-Aromatic polyamides such as copolymerized polyamides containing phenylenedoxydiacetic acid, particularly those containing nylon 6 and nylon 66 as essential components are particularly suitable because they themselves have an excellent balance of toughness and rigidity.

In the film of the present invention, when an aliphatic polyamide and an aromatic polyamide are used in combination as the polyamide resin component, the composition thereof is not particularly limited, but from the viewpoint of the balance between gas barrier property and flexibility, aromatic polyamide and aromatic polyamide are used. The proportion of polyamide is preferably 5 to 80% by weight, more preferably 10 to 60% by weight, most preferably 10 to 5% by weight.
0% by weight. However, from the viewpoint of gas barrier properties, the proportion of the aromatic polyamide is preferably as large as possible.

The layered phosphates of tetravalent cations in the present invention include tetravalent cations of metals such as elements of groups 4A and 4B of the periodic table such as titanium, zirconium and tin, cerium and thorium, and phosphates. composed of group (PO4 ^3-) and / or stearic acid (PO3 ^3-). Its structure is shown in FIG.
As shown in the structural model of α-zirconium phosphate shown in (4), tetravalent cations arranged on the same plane are cross-linked by phosphate groups, and three of the four oxygen atoms of each phosphate group are replaced with tetravalent cations. Which forms an octahedral coordination of six oxygen atoms around a tetravalent cation, and the negative charge of the remaining oxygen atoms of each phosphate group is neutralized by the positive charge of hydrogen ions It is. Also included are layered phosphoric acid / phosphorous acid mixed salts in which the phosphite group has partially substituted the above phosphoric acid group. Further, a part or all of the hydrogen ions neutralizing the negative charge of the oxygen atom of the phosphate group or the phosphite group is a metal cation,
It may be ion-exchanged with onium ions such as ammonium ions and phosphonium ions.

Layered phosphates of tetravalent cations can be prepared by adding a high concentration of phosphoric acid, phosphoric acid and phosphorous acid, or a water-soluble salt thereof to an aqueous solution containing tetravalent cations such as titanium, zirconium and tin. And the resulting amorphous gel is heated together with the mother liquor. Also, as a method for synthesizing the layered salts, many other methods are known in addition to the above, and the present invention is not limited to the above-described synthesis method.
Layered salts can be synthesized by various modifications.

The layered phosphates of tetravalent cations include:
α-titanium phosphate, β-titanium phosphate, γ-titanium phosphate, ammonium ion exchanger of titanium phosphate, titanium phosphate / phosphite, α-zirconium phosphate, β-zirconium phosphate, γ-phosphorus Zirconium phosphate, ammonium ion exchanger of γ-zirconium phosphate, zirconium phosphate / phosphite, α-tin phosphate, phosphoric acid / tin phosphite and the like. Here, α-type refers to a crystal structure in which a metal atom in the lower layer adjacent immediately below the phosphorus atom is located,
The type means a crystal structure in which an adjacent lower phosphorus atom is located immediately below the phosphorus atom. γ-type means a crystal structure in which a water molecule layer is interposed between the β-type layers.

By the way, elements of the 4A and 4B groups of the periodic table,
For cerium and thorium, the above layered salt is
Are known. Also, instead of phosphoric acid and phosphorous acid, arsenic acid
(H _ThreeAsO_Four) And zinc arsenate (H_ThreeAsO_Three)
It is also known that the same layered salt as above is formed when used.
Have been. Therefore, in principle, it is obtained from each of the above components.
The same effect as the present invention can be obtained by the layered salt obtained.
Expected. However, in the present invention, metal
Of stability of compounds, availability of raw materials, and safety
From the viewpoint, it is preferable to use a cycle of titanium, zirconium, tin, etc.
Examples include elements of groups 4A and 4B in the table, and more preferably
Tan, zirconium, tin, particularly preferably titanium, di
Ruconium, most preferably zirconium
You. Phosphoric acid is preferred as phosphoric acid and / or phosphorous acid
Used for Layered salts preferably used among these
Is α-zirconium phosphate,
γ-zirconium phosphate, zirconium phosphate / phosphite
Zirconium phosphates such as

In the film of the present invention, at least 50% of the tetravalent cation layered phosphate contained in the polyamide resin composition has an interlayer distance of 15 Å or more in the polyamide resin. Here, the interlayer distance is the distance between the centers of gravity of the layers with the nearest layer. Also, the larger the interlayer distance in the resin, the better the dispersion state is, which is desirable. 15 in the polyamide resin composition
The layered salt having an interlayer distance of not less than Å is 5
If it is less than 0%, the effect of improving gas barrier properties is insufficient, and the percentage is preferably 70% or more, most preferably 90% or more. This is because it is considered that the improvement of gas barrier properties is caused by the hindrance of diffusion of gas molecules in the polyamide resin by the dispersion layer, so that a dispersion state is required such that the interlayer distance with the nearest layer becomes larger than a certain extent. It is estimated to be.

The layered phosphate of a tetravalent cation used in the present invention has an interlayer distance of 15 angstroms or more, preferably 15 to 50 angstroms. Layered phosphates of tetravalent cations having a structure in which the interlayer distance of the layered salt is less than 15 angstroms have extremely low dispersibility in a polyamide resin. It is desirable to adopt a manufacturing method in which no more than 50% remains in the film.

The amount of the interlayer distance in the resin is determined by cutting a film from a film with a microtome or the like.
An image obtained by observing a thin section of about 00 nm with a transmission electron microscope can be obtained by, for example, performing image processing calculation using a computer. In the composition of the polyamide resin and the layered phosphate of the present invention, the content of the layered phosphate of the tetravalent cation is not particularly limited, but is 0% in terms of balance between gas barrier properties and mechanical properties. It is preferably in the range of 0.01 to 30% by weight, and most preferably in the range of 0.1 to 10% by weight. If the content is less than 0.01% by weight, the gas barrier property is hardly improved,
If it exceeds 30% by weight, the toughness of the film is greatly reduced,
In any case, the object of the present invention cannot be achieved. The content of the layered salt can be determined by combining weight analysis of the residue obtained by burning off the organic component, elemental analysis of the film, and the like.

Layered phosphates of tetravalent cations, which are layered salt derivatives having an interlayer distance as described above, are exemplified by tetravalent cation-extended layered phosphate in water or an aqueous solution of a linear ω-amino acid. It can be easily prepared by dispersing a layered phosphoric acid / phosphorous acid mixed salt of a salt and / or a tetravalent cation. That is, it is preferable to insert an organic onium ion between the tetravalent cation layers in advance.

By the above dispersion treatment, long hydrogen bonds and v
A linear ω-amino acid penetrates between the layers of the layered salt relatively loosely bound by the der Waals force, and the amino group neutralizes the strongly acidic OH group bonded to the phosphorus atom to form a linear ω-carboxy. It is believed that an alkyl ammonium salt derivative is formed. As a result, the interlayer distance increases according to the chain length of the linear alkyl. The aqueous solution in the above dispersion treatment is used when the linear ω-amino acid has insufficient water solubility. The aqueous solution is prepared by adding an appropriate water-soluble organic solvent to water.

When the interlayer distance is to be increased by using a linear ω-amino acid, the linear ω-amino acid having 6 or more carbon atoms is used.
It is important to use amino acids. When a linear ω-amino acid having less than 6 carbon atoms is used, the effect of increasing the interlayer distance of the layered salt is not sufficient. The upper limit of the number of carbon atoms of the linear ω-amino acid is not particularly limited, but is usually 20 from the viewpoint of solubility in water or an aqueous solution.
The preferred carbon number of the linear ω-amino acid is in the range of 6-15.

Specific examples of linear ω-amino acids having 6 or more carbon atoms include 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid,
0-aminodecanoic acid, 11-aminoundecanoic acid, 12
-Aminododecanoic acid, 13-aminotridecanoic acid, 14
-Aminotetradecanoic acid, 15-aminopentadecanoic acid and the like. In particular, from the viewpoint of the effect of increasing the interlayer distance, water solubility, and availability, 10-aminodecanoic acid,
2-Aminododecanoic acid is preferably used. In the film of the present invention, as a polyamide resin component, an aliphatic polyamide such as nylon 6 or nylon 66, a polyamide obtained from terephthalic acid and / or isophthalic acid and hexamethylenediamine, and adipic acid and meta-xylylenediamine When an aromatic polyamide such as a polyamide obtained from terephthalic acid, adipic acid and hexamethylenediamine, and a copolymerized polyamide containing 1,3-phenylenedioxane acetic acid as a copolymer component are used in combination, mechanical Very good balance between physical properties and gas barrier properties, especially gas barrier properties under high humidity conditions, is preferred.This is because of the flexibility and toughness of aliphatic polyamides and the superiority of aromatic polyamides. Gas barrier properties, especially in high humidity conditions The use of layer phosphates of tetravalent cations as a component imparting further gas barrier properties minimizes the decrease in flexibility, which is a drawback of the prior art. It is thought to be due to this. By maintaining such flexibility, toughness such as pinhole resistance and tear resistance, and handleability and adhesion when formed into a film are improved. The cause of these characteristics of tetravalent cation layered phosphates is unclear, but is due to differences in the mechanical properties of the layer itself due to differences in its crystal structure, for example, compared to layered silicates used in the prior art. It is also considered something.

The method for producing the film of the present invention is not particularly limited. For example, as described in JP-A-5-306370, a layered phosphate of a tetravalent cation having an ω-amino acid introduced between layers may be used as a polyamide. Suitable methods include melt molding such as T-die extrusion molding and blow molding of the composition obtained by dispersing and polymerizing the monomer.

For example, (i) a method of obtaining an extruded sheet using an extruder, a method of stretching the sheet in a machine direction and / or a machine direction to form a film, and / or forming using a deep drawing machine. Method, (ii) a method of molding a bottomed cylindrical primary molded article using an injection molding machine, and biaxially stretch blow molding the primary molded article, and (iii) a method of blow molding using a blow molding machine. And the like. The thickness of the gas barrier film of the present invention is preferably 1 μm or more.

When used in a laminated state, any or all of the layers may be uniaxially or biaxially oriented, and the orientation may be the same or different. As a method of forming a laminate, a method of co-extrusion using a plurality of extruders to form a film or a sheet, and further stretching the film or sheet extruded in this manner in the machine direction and / or the cross direction. And / or molding using a deep drawing molding machine; two types of resin are separately plasticized using two injection molding machines, and the two types of resin are injected into the same cavity of the mold almost simultaneously. A method of forming a bottomed cylindrical forming primary molded product having a multilayer structure of two or two layers or two or three layers, and blow molding the primary molded product into a multilayer container (laminated bottle); After forming two-type two-layer or two-type three-layer pipe-shaped primary molded products using an extruder, one end is welded to form a container bottom, the other end is pressed and deformed to form a mouth, and then blow molding is performed. To make a multi-layer container; Arm, leave produce a sheet,
Examples include a method of thermocompression bonding of both, but the method is not limited to these methods.

As long as the object of the present invention is not impaired, fumed silica, talc, kaolin, glass beads, glass flakes, clay, calcium carbonate,
Inorganic fillers such as calcium sulfate, alumina, titania,
Thermoplastic resins such as polyethylene, polypropylene, polyphenylene ether, aromatic polycarbonate, aromatic polyester, ethylene-α-olefin copolymer, polyamide elastomer, polyester elastomer, styrene thermoplastic elastomer, acrylic rubber, epoxy resin, ionomer resin and Acid-modified products obtained by modifying these with unsaturated carboxylic acids such as maleic anhydride, calcium stearate, lubricants such as barium stearate, heat stabilizers used for other polyamide resins, ultraviolet absorbers,
It is also possible to mix additives such as pigments, antioxidants, plasticizers, and antistatic agents.

The gas barrier film of the present invention can be applied to any molded product such as a film or a sheet, and a container or a bottle formed therefrom. For example, it is used for a film for food packaging, particularly a retort treatment, a film for food packaging and the like. Further, it is also possible to use laminated with other thermoplastic resins such as polyethylene, polyvinyl chloride, acid-modified ethylene-α-olefin copolymer, ionomer resin, and for fuels such as gasoline and fuel gas. It is used for gas barrier layers of tanks and hoses, interiors of metal cans, medical infusion bags, and the like. The oxygen permeation rate of the gas barrier film was 23 ° C. and the relative humidity was 9
At 5%, 100 (cc / cc) per 25 μm thickness
(day / cm ² / atm) or less, more preferably 90 or less, and particularly preferably 85 or less.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following example,
The evaluation was performed by the following method, and the results are listed in Table 1. (1) Interlayer distance “Rotaflex RU-200” manufactured by Rigaku Denki Co., Ltd.
The scattering spectrum was measured using a “BV type” X-ray irradiator (X-ray wavelength 1.5406 Å).

(2) Gas barrier property "OXTRAN 10 /" manufactured by Modern Control Co., Ltd.
23 ° C., 95% using a 50H type oxygen transmission rate measuring device
The oxygen transmission rate at% relative humidity was measured. In addition, for typical ones, at 40 ° C, 90 according to JIS Z0208.
The water vapor transmission rate at% relative humidity was also measured. Each transmission speed was converted to a value per 25 μm thickness. (3) Flexibility For typical ones, 23 according to JIS K6781
A tensile test in the MD direction of the film conditioned at 65 ° C. and a relative humidity of 65% was performed to measure the tensile modulus.

(4) Ash Content of Product Approximately 1.5 g of a film was precisely weighed, put into a crucible, carbonized with a gas burner, then ashed in an electric furnace at 500 ° C. for 1 hour, and calculated from the weight of the residue. (5) Dispersion state A thin section having a thickness of about 100 nm cut by a plane perpendicular to the plane direction of the film was prepared by a microtome, and the film was obtained by computer image processing of an observation image obtained by a transmission electron microscope H7000 manufactured by Hitachi, Ltd. The percentage of the layered salt having an interlayer distance of not less than 15 angstroms with respect to all the dispersion layers in the sample was determined.

REFERENCE EXAMPLE 1: Synthesis of α-zirconium phosphate 300 g of phosphoric acid was dissolved in 2.5 liters of 2N hydrochloric acid, and 400 g of zirconium chloride · octahydrate was added thereto.
A solution dissolved in 1.3 liters of N hydrochloric acid was added over 3 minutes with sufficient stirring while cooling with ice. Immediately, a white solid (zirconium phosphate gel) was formed. The stirring was stopped and the mixture was allowed to stand at room temperature overnight. It was then filtered off and washed with copious amounts of water until no chloride ions were detected in the silver nitrate test. The zirconium phosphate gel thus obtained was stirred in 5 liters of a 10 M aqueous phosphoric acid solution, and heated and refluxed in a slurry state for 62 hours. Thereafter, the white solid was filtered off and washed with a large amount of water. The white solid thus obtained is
A layered periodic structure having an interlayer distance of 7.4 angstroms was confirmed, and other X-ray scattering patterns were completely identical to those of α-zirconium phosphate.

Reference Example 2: Insertion of 12-aminododecanoic acid between α-zirconium phosphate layers 270 g of α-zirconium phosphate obtained in Reference Example 1 was stirred and suspended in 25 liters of water (80 ° C.). Then, 290 g of 12-aminododecanoic acid was added thereto, and stirring was continued for 6 hours. After the stirring was stopped and the mixture was allowed to stand at room temperature for 5 days, the solid was separated by filtration. The obtained solid was washed with a large amount of water, and then dried in a hot air oven at 50 ° C. to obtain a powder. The solid obtained in this way had an interlayer distance expanded to 22.0 angstroms.

Example 1 130 g of the solid obtained by inserting 12-aminododecanoic acid between the α-zirconium phosphate layers obtained in Reference Example 2, 3021 g of ε-caprolactam, and 320 g of 6-aminohexanoic acid were mixed. It was sealed in a liter autoclave with a stirrer. After replacing the inside with nitrogen, the mixture was stirred at atmospheric pressure at 100 ° C for 90 minutes, and then heated at 250 ° C.
After the temperature was raised, the polymerization reaction was further performed at atmospheric pressure for 2 hours, and then under reduced pressure (maximum degree of vacuum 100 Torr) for 6 hours. When the obtained polyamide composition was taken out, it was almost completely transparent in a molten state. After the chips were formed, residual low molecular weight substances were extracted in boiling water, followed by hot air drying at 80 ° C. for 2 hours and then vacuum drying at 100 ° C. for 18 hours.

A dry blend of 70% by weight of the thus obtained dried polyamide composition chips and 30% by weight of dried chips of Novamid 1020J (number average polymerization degree: about 230, Novamid is a registered trademark) of Nylon 6 manufactured by Mitsubishi Kasei Co., Ltd. Then, the extruder was extruded with a device having a T-die attached to an extruder having a single screw having a diameter of 40 mm to obtain a film having a thickness of 25 μm. At this time, the barrel of the extruder was 240 ° C and the T-die was 2
50 ° C, resin temperature 235 ° C, take-up roll temperature 1
The temperature was set to 00 ° C. and the screw rotation speed was set to 30 rpm. The film thus obtained was very smooth and excellent in transparency. Next, the oxygen and water vapor transmission rates, flexibility, and dispersion state of the film were evaluated, and the results are shown in Table 1. The dried composition chip was dissolved in concentrated sulfuric acid (1 g / dl).
When the relative viscosity at 25 ° C. was measured, it was 3.21 and the number average degree of polymerization was found to be about 210.

Example 2 The dried polyamide composition chips obtained in Example 1 and Novamid X21, an amorphous aromatic polyamide manufactured by Mitsubishi Kasei Corporation (polyamide comprising terephthalic acid, isophthalic acid, and hexamethylenediamine) And a dried chip having a number average degree of polymerization of about 80) is 70/3.
It was dry-blended at a ratio of 0 (% by weight), formed into an extruded film in the same manner as in Example 1, and evaluated for the oxygen and water vapor transmission rates and the dispersion state.

Example 3 Meta-xylylenediamine 13
86 g, isophthalic acid 1014 g, adipic acid 595
g, 6.10 g of acetic acid and 2897 g of water were charged into the autoclave equipped with a stirrer of Example 1, the temperature was increased after purging with nitrogen, and the internal pressure was 2.5 kg / cm.
^{When the} pressure reached ² , the valve of the autoclave was opened and water was distilled and concentrated while maintaining this internal pressure. During the concentration, the temperature was continued to be raised. When the internal temperature reached 190 ° C., the valve of the autoclave was closed, and the temperature was further raised. Next, if the internal pressure is 1
When the pressure reached 4 kg / cm ² , the valve was opened again, and water was distilled and concentrated while maintaining this internal pressure. During the concentration, the temperature was kept elevated. When the internal temperature reached 230 ° C., the pressure was released to the atmospheric pressure, and then the polymerization reaction was continued at this temperature for 1 hour. After completion of the reaction, the aromatic polyamide taken out of the autoclave had a relative viscosity of 2.0 under the conditions described in Example 1 and was amorphous. After forming the amorphous aromatic polyamide into chips, vacuum drying at 110 ° C. was performed for 32 hours. Then, in the same manner as in Example 2, 70% by weight of the dried polyamide composition chip obtained in Example 1 was dry-blended and then formed into an extruded film, and the oxygen permeation rate and the dispersion state were evaluated.

Example 4 50% by weight of chips of the polyamide composition of Example 1, 15% by weight of chips of the amorphous aromatic polyamide of Example 2, and the amorphous aromatic polyamide prepared in Example 3 After dry-blending 35% by weight of the chips, an extruded film was formed in the same manner as in Example 1, and the oxygen permeation rate and the dispersion state were evaluated.

Comparative Example 1 Only the nylon 6 chip used in Example 1 was extruded into a film in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 1. [Comparative Example 2] 270 g of Kunipia F, a high-purity Na montmorillonite manufactured by Kunimine Industries Co., Ltd. (cation exchange capacity measured by a methylene blue adsorption method is 120 meq / 100 g, interlayer distance is 12.5 angstroms, Kunipia is a registered trademark) is 25. The suspension was stirred and suspended in 1 liter of water (30 ° C.), and thereto was added concentrated hydrochloric acid in an amount equivalent to 84 g of 12-aminododecanoic acid and an equimolar amount of HCl, and stirring was continued for 6 hours. After stirring was stopped and the mixture was allowed to stand at room temperature for one day, the solid was separated by filtration. The obtained solid was washed with a large amount of water until no chloride ion was detected in the silver nitrate test, and then dried in a 50 ° C. hot air oven to obtain a powder. The solid thus obtained is
The interlayer distance was expanded to 17.2 angstroms.
130 g of a solid having 12-aminododecanoic acid inserted between layers of this montmorillonite, ε-caprolactam 3021
g, and 320 g of 6-aminohexanoic acid.
The mixture was sealed in a liter autoclave equipped with a stirrer, and a polyamide composition was prepared in the same manner as in Example 1.
Furthermore, mixing with nylon 6 chips, extruded film formation, and evaluation were all performed in the same manner as in Example 1.

[0038]

[Table 1]

[0039]

The gas barrier film of the present invention has both flexibility and excellent gas barrier properties.
Since it exhibits excellent film barrier properties even in a high-humidity state and has appropriate flexibility, it can be suitably used in food packaging, particularly in applications requiring retort treatment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structural model of a unit layer of α-zirconium phosphate.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J 5/18 C01B 25/37 C08K 5/51-5/5397 C08L 77/00-77/12

Claims (5)

(57) [Claims] 1. A ing films from a polyamide resin composition containing a 4 Ataihi layered phosphate salts of ions, Po
When the amide resin is 95 to 20% by weight of an aliphatic polyamide,
Ri Na from aromatic polyamide 5-80 wt%, and, 4 Ataihi
The content of the ion layered phosphates is 0.01 to 30% by weight.
% And 50 % of the layered phosphate of tetravalent cations.
% Or more having an interlayer distance of 15 Å or more in the polyamide resin composition. 2. The gas barrier film according to claim 1, wherein the tetravalent cation layered phosphates are zirconium phosphates. 3. 70% of layered phosphates of tetravalent cations
The claim 1, characterized in that the above has an interlayer distance greater than 15 angstroms in the polyamide resin composition
Is a gas barrier film according to 2. 4. 90% of layered phosphates of tetravalent cations
The claim 1, characterized in that the above has an interlayer distance greater than 15 angstroms in the polyamide resin composition
Is a gas barrier film according to 2. 5. 25 μm at 23 ° C. and 95% relative humidity.
m is 100 (cc / day)
/ Cm ² / atm) or less, the gas barrier film according to any one of claims 1 to 4 , wherein