JP2000043219A - Plastic film laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier plastic film having excellent gas barrier properties suppressed in temp. and humidity independence, capable of seeing content, enabling the use of a metal detector, based on a wide range of plastic materials and excellent in film forming properties and adhesion. SOLUTION: A gas barrier plastic film laminate is constituted by successively laminating an adhesion layer 2 containing a polyurethane resin as a main constitutional component and a gas barrier film layer 3 containing an inorg. laminar compd. and a water-soluble polymer as main constitutional components to at least the single surface of a base material 1 comprising a plastic material and adding a surfactant to at least one of the base material 1 and the adhesion layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic film laminate for packaging used in the field of packaging non-foodstuffs such as foodstuffs, pharmaceuticals and electronic components, etc. The present invention relates to a plastic film laminate that blocks contents from oxygen and water vapor and suppresses deterioration and deterioration.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, non-foods, and the like are required to suppress deterioration of contents and maintain their functions and properties. It is necessary to prevent the influence of the gas that alters the substance, and it is required to have a gas barrier property that blocks these gases (gas).

[0003] Conventionally, as a gas barrier layer, a metal foil made of a metal such as aluminum, a vapor-deposited film thereof, a resin film such as polyvinyl alcohol or ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, or a resin of these resins. A plastic film coated with an inorganic oxide such as silicon oxide and aluminum oxide has been mainly used.

[0004]

However, metal foils and vapor-deposited films are excellent in gas barrier properties, but the contents cannot be confirmed by seeing through the packaging material, the metal detector cannot be used in the inspection, and the disposal after use. In such a case, there is a problem that it must be treated as an incombustible substance. In addition, gas barrier resin films and films coated with them have high temperature and humidity dependence and cannot maintain high gas barrier properties, and furthermore, vinylidene chloride, polyacrylonitrile, etc. may generate harmful substances when discarded or incinerated. There is such a problem. In addition, ceramic deposited films, etc.
There are problems that the vapor deposition layer lacks flexibility due to ceramics, and that sufficient attention must be paid to processing suitability, and that the cost is high due to the expensive processing machine.

As a technique for solving such a problem, a gas barrier resin film in which a gas barrier coating whose main component is a water-soluble polymer such as polyvinyl alcohol and whose temperature and humidity dependence is suppressed is laminated on a base material such as a plastic film. There is. In this case, by laminating a gas barrier coating layer having film forming properties and adhesion to a plastic material by a wet coating method, it is possible to manufacture at low cost.

An object of the present invention is to solve the above-mentioned problems of the prior art, and has an excellent gas barrier property in which the temperature and humidity dependence is suppressed, the contents can be seen through, and a metal detector is provided. It is another object of the present invention to provide a gas-barrier plastic film laminate having excellent film-forming properties and adhesiveness using a wide range of plastic materials as a substrate.

[0007]

According to the present invention, in order to achieve the above-mentioned object, first, in claim 1, at least one surface of a base material made of a plastic material is provided with an adhesion layer mainly composed of a polyurethane resin. A gas barrier property layer comprising an inorganic layered compound and a water-soluble polymer as main constituents are sequentially laminated, and at least one of the base material and the adhesion layer contains a surfactant. , And a plastic film laminate provided with

According to a second aspect of the present invention, there is provided the plastic film laminate according to the first aspect, wherein the surfactant is mixed in the adhesion layer.

According to a third aspect of the present invention, there is provided the plastic film laminate according to the first or second aspect, wherein the surfactant is a cationic surfactant.

The plastic film laminate according to any one of claims 1 to 3, wherein the gas barrier coating layer contains a hydrolyzate of a metal alkoxide. It is what it was.

According to a fifth aspect of the present invention, there is provided the plastic film laminate according to the fourth aspect, wherein the metal constituting the metal alkoxide is Si, Al or Ti.

According to a sixth aspect of the present invention, the plastic film laminate according to any one of the first to fifth aspects, wherein the water-soluble polymer is a polyvinyl alcohol or a derivative thereof. It is.

Further, in the present invention, the interlayer distance of the inorganic layered compound in the gas barrier coating layer is 1 to the interlayer distance of the inorganic layered compound alone before forming the gas barrier coating layer with the water-soluble polymer. A plastic film laminate according to any one of claims 1 to 6, characterized in that the plastic film is magnified twice or more.

According to an eighth aspect of the present invention, there is provided the plastic film laminate according to any one of the first to seventh aspects, wherein the inorganic layered compound is montmorillonite.

[0015]

According to the present invention, a composite film of a water-soluble polymer and an inorganic layered compound is used as a gas barrier coating layer in a structure in which an adhesion layer and a gas barrier coating layer are sequentially laminated on a plastic substrate. It has high gas barrier properties with reduced temperature and humidity dependence. Furthermore, since both the adhesion layer and the gas barrier coating layer can be applied in-line by wet coating, existing gravure printing machines can be used, continuous production is possible, and low-cost processing is possible.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a plastic film laminate of the present invention.

The plastic film laminate of the present invention shown in FIG. 1 will be described. In FIG. 1, a base material 1 is a film made of a plastic material, and an adhesive layer 2 having a polyurethane resin as a main component, and a gas barrier of a composite film having an inorganic layered compound and a water-soluble polymer as a main component. The functional coating layers 3 are sequentially laminated.

Further, in the present invention, in order to form the gas barrier coating layer 3 in a preferable state, at least one of the base material 1 and the adhesion layer 2 contains a surfactant, and particularly, a gas barrier material is applied to a wide range of base materials. In order to form the conductive composite material as a coating, it is preferable to add a surfactant to the adhesion layer 2 containing a polyurethane resin as a main component.

The above-mentioned substrate 1 is made of a plastic material, and is preferably transparent. For example, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films such as 6-nylon, polycarbonate films, polyacrylonitrile films, and engineering plastics such as polyimide films. A film or the like is used, which may be stretched or unstretched, and a film having mechanical strength and dimensional stability is preferred. These are processed into a film and used. In particular, among these, films stretched arbitrarily in the biaxial direction are preferably used, and when used as a packaging material, in consideration of price, printability, filling suitability, hand, disposability, physical strength, and the like. Biaxially stretched polypropylene films, polyester films and polyamide films are more preferred.

Various known additives and stabilizers, for example, an antistatic agent, a plasticizer, a lubricant, an antioxidant, etc., may be used on the surface of the base material 1. In order to improve the performance, a corona discharge treatment, a low-temperature plasma treatment, an ozone treatment, a flame treatment, or the like may be performed as a pretreatment, and a chemical treatment or a solvent treatment may be further performed.

The thickness of the substrate 1 is not particularly limited, but is suitable as a packaging material, that other layers may be laminated, and processing when the adhesion layer 2 and the gas barrier coating layer 3 are formed. Considering the properties, practically 3 to 200 μm
Within the range of m, the thickness is more preferably 6 to 30 μm depending on the use.

The adhesion layer 2 of the present invention is provided on at least one surface of a substrate 1 made of a plastic material, and is a coating of a gas barrier coating layer 3 made of a composite of the substrate 1 and a water-soluble polymer and an inorganic layered compound. It is provided for the purpose of improving formability and adhesion between layers. In order to achieve the above object, the adhesion layer 2 is a polyurethane resin, and the polyurethane constituting the adhesion layer 2 is preferably applied to at least one of the substrate 1 and the adhesion layer 2, preferably to cover a wide range of plastic materials. It is preferable that a surfactant is mixed with and added to the system resin. As described above, the surfactant is preferably used as a mixture with the polyurethane-based resin constituting the adhesion layer 2. However, when a plastic material having a surfactant added to the base material 1 is used, When a surfactant is contained, sufficient film-forming properties of the gas-barrier coating layer 3 and adhesion between layers may be obtained without mixing the surfactant into the adhesion layer 2. Need not be mixed with a surfactant in the adhesion layer 2. When using a commercially available film as the film used for the substrate 1,
Polypropylene films and the like often contain a surfactant in advance for the purpose of improving the wettability of a coating solution, and in the case of a polyester film or the like, even if a surfactant is added, the wettability is not significantly improved. In many cases, no surfactant is contained for such reasons. However, when the substrate 1 contains a surfactant, the film-forming properties of the gas barrier coating layer 3 and the adhesion between the layers are not always obtained, and the surfactant is mixed in the adhesion layer 2. It is preferable to mix and add a surfactant to the polyurethane-based resin as described above, since it is generally more economical.

The polyurethane resin is not particularly limited as long as it has a urethane bond in the main chain or side chain. Examples thereof include those having a urethane bond in the main chain or side chain as well as polyester polyols. A urethane bond may be formed by reacting a polyol such as polyether polyol or acrylic polyol with an isocyanate compound having an isocyanate group.
Among them, a polyurethane resin obtained by mixing a polyester polyol such as a condensation-based polyester polyol or a lactone-based polyester polyol with an isocyanate compound such as tolylene diisocyanate, hexamethylene diisocyanate, or xylene diisocyanate is preferable because it has the best adhesion.

A known method can be used for mixing the two, and is not particularly limited. The blending ratio is not particularly limited, but if the amount of the isocyanate compound is too small, curing failure may occur. Therefore, preferably, the OH group derived from the polyol and the NCO group derived from the isocyanate compound are equivalent to 1: 0. 5-
1:40.

The term "surfactant" is a generic term for an organic composition having a lipophilic group and a hydrophilic group, and has an effect of joining hydrophilic and lipophilic contradictory properties. Emulsifier, dispersant, antistatic agent, lubricant,
It is used for pigment dispersants, various catalysts and the like. Surfactants are classified into anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants according to differences in hydrophilic groups. By adding these to the polyurethane resin constituting the adhesion layer, the surface of the adhesion layer is modified to be hydrophilic, which is effective in forming the gas barrier coating layer. In consideration of economy, a cationic surfactant such as an amine or a pyridine derivative, which can provide a sufficient effect with a small amount of addition, is more preferable.

The reason that the cationic surfactant exerts its function sufficiently even in a small amount is that the surface of the silicic acid tetrahedral layer on the side where the surface area of the inorganic layered compound, which is a constituent of the gas barrier coating layer, is large is negatively charged. Because the cationic surfactant charges the coating surface of the adhesion layer with a positive charge (cation), the inorganic layered compound in the gas barrier coating layer is oriented in parallel with the adhesion layer interface. It is thought that it is.

Regarding the addition amount of the surfactant, the mixing ratio of the polyurethane resin / surfactant is 1000 by weight.
The range of 0/1 to 10/1 is preferred. If it is less than 10,000 / 1, the effect on the formation of the film cannot be seen,
If the ratio is more than 10/1, it reacts with the isocyanate compound in the solution before coating to form a precipitate or the like, and the surfactant is relatively expensive, and thus lacks economy.

The thickness of the adhesion layer 2 is not particularly limited. However, if the thickness is less than 0.001 μm, the adhesion effect and the effect of forming a film with a surfactant are weakened, and if it is more than 1 μm, it is uneconomical. Not preferred. Generally 0.001
It is preferable that the thickness is in the range of 0.05 to 0.5 μm in practice. The drying method is not particularly limited, and a normal method or the like may be used.

Next, the gas barrier coating layer 3 of the present invention will be described. The purpose of this layer is to provide a high gas barrier property and suppress temperature dependency and humidity deterioration. In order to achieve the above object, the gas barrier coating layer is a composite coating mainly composed of an inorganic layered compound and a water-soluble polymer, and more preferably, the interlayer distance of the inorganic layered compound is a complex with a water-soluble polymer. That is, it is 1.2 times or more, and more preferably 2 times or more, the interlayer distance of the inorganic layered compound alone before the film is formed.

The interlayer distance is determined by the X-ray diffraction method using the bottom reflection (001) of the inorganic layered compound in the gas barrier coating layer.
Plane) can be calculated. That is,
According to the calculation based on the X-ray diffraction method, the interlayer distance of the above-mentioned inorganic layered compound before mixing with the water-soluble polymer varies depending on the type of the inorganic layered compound and the type of the water-soluble polymer,
Usually it is 7 to 15 °. On the other hand, the interlayer distance of the inorganic layered compound in the gas barrier coating layer in the present invention is 1.2 times or more thereof, and more preferably 2 times or more in order to have gas barrier properties.

In the present invention, the inorganic layered compound and the water-soluble polymer are not merely mixed and dispersed in the gas barrier coating layer, but the water-soluble polymer expands between the layers of the inorganic layered compound. And the inorganic layered compound and the water-soluble polymer are complexed at the molecular level. For this reason, it is considered that the gas barrier coating layer has high gas barrier properties and can suppress humidity deterioration and temperature dependency.

The gas barrier coating layer will be described in more detail. The inorganic layered compound in the gas barrier coating layer means a crystalline inorganic compound having a layered structure, such as kaolinite, halloysite, chlorite, smectite, vermiculite, pyrophyllite, and mica. Natural clay minerals, and synthetic products such as synthetic smectite. As long as it is an inorganic layered compound, its type, particle size, aspect ratio and the like can be appropriately selected depending on the required quality and the like, and are not particularly limited, but have a high swelling property and a layered structure. The inorganic layered compound of the smectite group is suitable because a water-soluble polymer enters between the layers and a gas barrier coating layer in which the layers are enlarged is easily obtained. Specific examples of the smectite group include montmorillonite, saponite, and the like. Among them, montmorillonite is more preferable in terms of swellability, dispersibility, price, workability, and the like.

On the other hand, the water-soluble polymer, which is another main component of the gas barrier coating layer, is not particularly limited as long as it is compatible with the inorganic layered compound and easily penetrates between the layers. For example, polyvinyl alcohols such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer or derivatives thereof, saccharides such as cellulose and starch, and polymers and derivatives such as polyacrylic acid and methacrylic acid can be used. Further, judging from the viewpoint of gas barrier properties, polyvinyl alcohol or a derivative thereof is more preferable.

The above-mentioned polyvinyl alcohol is a generic name of polymers having hydroxyl groups by polymerization and saponification (alkali treatment) of vinyl acetate, and the degree of saponification is not particularly limited. However, from partially saponified polyvinyl alcohol in which several tens% remains, to completely saponified polyvinyl alcohol in which only a few percent of acetic acid groups remain, ethylene-vinyl alcohol polymerized by further containing about 1 to 40 mol% of ethylene It can be widely used up to copolymers.

As for the method of mixing the inorganic layered compound and the water-soluble polymer, a general method can be employed and is not particularly limited. Although the value of the compounding ratio varies depending on the required quality, it is generally preferable that the weight ratio of the inorganic layered compound to the water-soluble polymer is in the range of 1:99 to 90:10.

In the formation of the gas barrier coating layer,
Adjustment of the interlayer distance of the inorganic layered compound in the gas barrier coating layer can be carried out by appropriately selecting the combination of the inorganic layered compound and the water-soluble polymer, the mixing ratio, the heating temperature during mixing, and the like.

It is also possible to add other components to the gas barrier coating layer for various purposes. For example, a hydrolyzate of a metal alkoxide or the like is added for the purpose of further improving the temperature / humidity dependence of gas barrier properties, the film strength, and the water resistance.

The metal alkoxide is represented by the general formula M (O
R) n (M is a metal element such as Si, Al, Ti, etc., and R is a lower alkyl group having 1 to 4 carbon atoms). In the present invention, for example, tetraethoxysilane or triisopropane Propoxy aluminum or the like can be used. In addition, as these hydrolysates, those in which a part of the alkoxide group is hydrolyzed or those in which all of the alkoxide groups are hydrolyzed can be used.

When a gas barrier coating layer containing a hydrolyzate of the metal alkoxide is obtained, a composite liquid obtained by mixing an inorganic layered compound and a water-soluble polymer is used.
What is necessary is just to add the hydrolyzate of a metal alkoxide. In this case, the amount of addition is preferably 1 to 80% by weight with respect to the composite liquid from the viewpoint of water resistance and flexibility.

In general, the gas barrier coating layer 3 is preferably coated so as to have a thickness after drying of 0.01 to 50 μm, more preferably 0.1 to 5 μm. Is adopted. When the thickness is less than 0.01 μm, it is difficult to obtain a uniform coating film.

As a method for forming the adhesion layer 2 and the gas barrier coating layer 3, a usual coating method can be used. For example, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, and the like can be used. The coating is applied to at least one surface of the substrate 1 using these coating methods. In this case, the adhesion layer 2 and the gas barrier coating layer 3 may be separately provided, or both layers may be simultaneously provided using a multicolor gravure printing machine or the like. Considering the cost, it is more preferable to form them at the same time. The drying method is not particularly limited, such as hot air drying, hot roll drying, and infrared irradiation.

Further, other layers can be laminated on the gas barrier coating layer 3. For example, it is a printing layer, a heat sealing layer, or the like. The printing layer is formed for practical use as a packaging bag or the like, and a conventionally used ink binder resin such as a urethane type, an acrylic type, a nitrocellulose type, a polyamide type, and a polyvinyl chloride type. A layer composed of an ink obtained by adding additives such as various pigments, a vehicle, a plasticizer, a desiccant, a stabilizer, and the like, in which characters and patterns are formed. As a forming method, for example, a general printing method such as an offset printing method, a gravure printing method, and a silk screen printing method can be used. The thickness is about 0.1 to 2.0 μm.

When a multi-color printing machine is used for laminating the printing layers, the adhesion layer 2 and the gas barrier coating layer 3 are provided first, and then the printing layers are stacked in the printing unit of the same printing machine.

The heat seal layer is used as an adhesive portion when forming a bag-like package, for example, polyethylene, polypropylene, ethylene-polyvinyl alcohol copolymer, ethylene-methacrylic acid copolymer, Resins such as an ethylene-methacrylic acid ester copolymer, an ethylene-acrylic acid copolymer, an ethylene-acrylic acid ester copolymer, and a metal crosslinked product thereof are used. Generally, the thickness is in the range of 15 to 200 μm.

As a method for forming the heat seal layer, a film-like material made of the above-mentioned resin is wet-cured in one liquid or cured in two liquids.
Dry lamination method of bonding with liquid reaction-curing urethane adhesive, non-solvent type dry lamination method of bonding with non-solvent adhesive, heat-melt thermoplastic resin such as polyethylene, and extrude to bond in a curtain shape Any of the lamination method and the like can be formed by a general lamination method.

[0046]

EXAMPLES The plastic film laminate having gas barrier properties of the present invention will be described in more detail with reference to specific examples.

<Adjustment of Coating Solution for Adhesion Layer> 1) Polyester polyol as a main component (molecular weight: about 200)
00), a coating liquid comprising a polyurethane resin component obtained by mixing tolylene diisocyanate (TDI) as an isocyanate compound in such a manner that an NCO group derived from an isocyanate compound becomes 1: 8 with respect to an OH group derived from a polyester polyol on an equivalent basis. 1 was obtained.

2) A nonionic surfactant (manufactured by NOF CORPORATION, trade name; Nonion N
S220) in terms of solid content weight ratio of polyurethane resin component 50
And a coating solution 2 for the adhesion layer in which a surfactant was mixed was obtained.

3) A cationic surfactant (manufactured by NOF Corporation, trade name: Cation A)
B) was added at a ratio of 1 to the urethane resin component 200 at a solid content weight ratio to obtain a coating liquid 3 for an adhesion layer in which a surfactant was mixed.

4) Polyethylene imine (trade name: AD372, manufactured by Toyo Ink Mfg. Co., Ltd.) was converted to water / methanol = 1.
The solution was diluted with a ４ solution to obtain a coating solution 4.

5) A coating liquid 5 was obtained by diluting a butadiene-based emulsion (trade name: EL451, manufactured by Toyo Ink Mfg. Co., Ltd.) with a water / methanol = 1/4 solution.

<Preparation of Gas Barrier Coating Layer Liquid> A) High purity montmorillonite was used as an inorganic layer compound.
Polyvinyl alcohol (degree of polymerization 17) as a water-soluble polymer
00) was diluted with water so as to have a weight conversion of 1: 1 to obtain a liquid A.

B) A hydrolyzate of tetraethoxysilane (TEOS) was added to solution A as an additive,
TEOS hydrolyzate = 6/4
A liquid was obtained.

C) Polyvinyl alcohol (degree of polymerization: 1700) as a water-soluble polymer was diluted with water to obtain a liquid C in which no inorganic stratiform compound was mixed.

<Example 1> As the substrate 1, a thickness of 20 μm
The coating liquid 1 was applied as a contact layer 2 by gravure coating to the corona discharge treated surface of a biaxially stretched surfactant-added polypropylene film (trade name: U-1 manufactured by Tocelo Co., Ltd.) at 80 ° C. And dried through an oven to form an adhesion layer. Next, the liquid A was applied as a gas barrier coating layer 3 by a gravure coating method, and dried by passing through an oven at 80 ° C. to form a gas barrier coating layer, thereby obtaining a plastic film laminate of the present invention.

<Example 2> In Example 1, the adhesion layer 2
Was used to obtain a plastic film laminate of the present invention in the same manner except that coating liquid 2 was used.

<Example 3> In Example 1, the adhesion layer 2
Was obtained in the same manner except that the coating liquid 3 was used.

<Comparative Example 1> In Example 1, the adhesion layer 2
A plastic film laminate was obtained in the same manner except that the coating liquid 4 was used.

<Comparative Example 2>
A plastic film laminate was obtained in the same manner except that the coating liquid 5 was used.

Example 4 As the substrate 1, a thickness of 20 μm
A coating liquid 3 was applied as a contact layer 2 to the corona discharge treated surface of a surfactant-free polypropylene film (manufactured by Tocelo Co., Ltd., trade name; M-1) which was biaxially stretched by a gravure coating method. The resultant was dried by passing through an oven at ℃ to form an adhesion layer. Next, as the gas barrier coating layer 3, A
The solution was applied by a gravure coating method and dried by passing through an oven at 80 ° C. to form a gas barrier coating layer, thereby obtaining a plastic film laminate of the present invention.

Example 5 As the substrate 1, a thickness of 12 μm
A coating liquid 3 is applied as a contact layer 2 by a gravure coating method to a corona discharge treated surface of a biaxially stretched polyethylene terephthalate film (trade name: P60, manufactured by Toray Industries, Inc.), and dried by passing through an 80 ° C. oven. Thus, an adhesion layer was formed. Next, the liquid A was applied as a gas barrier coating layer 3 by a gravure coating method, and dried by passing through an oven at 80 ° C. to form a gas barrier coating layer, thereby obtaining a plastic film laminate of the present invention.

Example 6 As the substrate 1, a thickness of 15 μm
A coating liquid 3 is applied as a contact layer 2 to the corona discharge treated surface of a biaxially stretched nylon film (manufactured by Unitika Ltd., trade name: ON-RT) by a gravure coating method.
And dried through an oven to form an adhesion layer. Next, the liquid A was applied as a gas barrier coating layer 3 by a gravure coating method, and dried by passing through an oven at 80 ° C. to form a gas barrier coating layer, thereby obtaining a plastic film laminate of the present invention.

<Comparative Example 3> In Example 4, the adhesion layer 2
A plastic film laminate was obtained in the same manner except that the coating liquid 1 was used.

<Comparative Example 4>
A plastic film laminate was obtained in the same manner except that the coating liquid 1 was used.

<Example 7> A plastic laminate of the present invention was obtained in the same manner as in Example 1, except that Liquid B was used as the gas barrier coating layer 3.

Comparative Example 5 A plastic film laminate was obtained in the same manner as in Example 1, except that the liquid C was used as the gas barrier coating layer 3.

<Evaluation> For each of the plastic film laminates of Examples and Comparative Examples, (1) the state of the gas barrier coating layer, and (2) the oxygen permeability (cc / m ² · day · at)
m), (3) cellophane tape adhesion, and (4) water resistance test.

(1) State of Gas Barrier Coating Layer The appearance of the coating after drying was observed, and sensory evaluation of coating unevenness, pinholes, etc. was visually made.

(2) Oxygen permeability Oxygen permeability measuring device (OXT, manufactured by Modern Control Co., Ltd.)
Using RAN-10 / 50A), the oxygen permeability was measured at 30 ° C. and 70% RH.

(3) Adhesion of cellophane tape A cellophane tape was adhered to the coated surface of each plastic film laminate, and then peeled off, and each layer was visually observed for peeling.

(4) Water Resistance Test Each plastic film laminate was immersed in tap water at room temperature for 1 minute, and immediately after being taken out, the coated surface was lightly wiped with a cloth to check the remaining state of the layer visually.

[0072]

[Table 1]

In contrast to Examples 1 to 3, Comparative Examples 1 and 2
Since the adhesion layer was formed of a water-soluble resin as the main component, the adhesion layer was re-dissolved when the gas barrier coating layer was formed, resulting in poor appearance such as coating unevenness, and increased oxygen permeability and poor adhesion. Further, Comparative Examples 3 and 4 were compared to Examples 4 to 6.
Is because no surfactant is added to the adhesion layer etc.
The formation state of the gas barrier coating layer is poor and pinholes are generated, and the oxygen permeability increases. In addition, in Comparative Example 5 as compared to Example 1, since montmorillonite was not contained in the gas barrier coating layer, an increase in oxygen permeability due to humidity dependence specific to polyvinyl alcohol was observed. By adding the metal alkoxide, the water resistance is improved while maintaining the oxygen permeability. The above-mentioned examples have a good gas-barrier coating layer state and can be said to be at a level that is sufficiently practical as a gas-barrier packaging material because of the high oxygen permeability and high adhesion.

[0074]

As described above, according to the present invention, when a gas-barrier coating layer of an inorganic layered compound and a water-soluble polymer is applied to a substrate made of a plastic film, a polyurethane resin is mainly used as an adhesion layer. In addition, by appropriately blending a surfactant into a substrate, an adhesive layer, and the like, a plastic film laminate having high gas barrier properties and practical as a packaging material can be produced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a plastic film laminate of the present invention.

[Explanation of symbols]

 1 Base material 2 Adhesion layer 3 Gas barrier coating layer

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Yoshihara 1-5-1, Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Takeshi Kenya 1-15-1, Taito, Taito-ku, Tokyo Letterpress Inside Printing Co., Ltd. (72) Inventor Mamoru Sekiguchi 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Tomonori Komori 1-1-1, Taito 1-5-1, Taito, Taito-ku, Tokyo Letterpress Inside printing company

Claims (8)

[Claims] An adhesive layer mainly composed of a polyurethane resin and a gas barrier coating layer mainly composed of an inorganic layer compound and a water-soluble polymer are sequentially laminated on at least one surface of a substrate made of a plastic material. A plastic film laminate provided with gas barrier properties, characterized in that at least one of the substrate and the adhesion layer contains a surfactant. 2. The plastic film laminate according to claim 1, wherein the surfactant is mixed in the adhesion layer. 3. The plastic film laminate according to claim 1, wherein the surfactant is a cationic surfactant. 4. The plastic film laminate according to claim 1, wherein a hydrolyzate of a metal alkoxide is contained in the gas barrier coating layer. 5. The metal constituting the metal alkoxide,
The plastic film laminate according to claim 4, wherein the plastic film laminate is Si, Al, or Ti. 6. The plastic film laminate according to claim 1, wherein the water-soluble polymer is a polyvinyl alcohol or a derivative thereof. 7. The interlayer distance of the inorganic layered compound in the gas barrier coating layer is set to be 1.about. The interlayer distance of the inorganic layered compound alone before forming the gas barrier coating layer with the water-soluble polymer.
The plastic film laminate according to any one of claims 1 to 6, wherein the plastic film is enlarged by a factor of two or more. 8. The plastic film laminate according to claim 1, wherein the inorganic layered compound is montmorillonite.