JPH11147276A - Gas barrier transparent laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a packing material excellent in transparency, having high gas barrier properties, not causing the deterioration of physical properties even after boil sterilization and high in practicality. SOLUTION: A gas barrier transparent laminate 10 useful for a packing material has a layered constitution wherein a transparent primer layer 2 comprising a mixture of an acryl polyol and an isocyanate compd. and a vapor- deposited membrane layer 3 comprising inorg. oxide are successively laminated, and a polyolefinic thermoplastic resin layer 6 is further laminated thereon as a seal layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate used for packaging foods, pharmaceuticals and other non-food items, and more particularly to a laminate used as a packaging material for packaging requiring boil sterilization or the like.

[0002]

2. Description of the Related Art Packaging materials used for the packaging of foods, pharmaceuticals and other non-foodstuffs include oxygen, water vapor, and other materials for suppressing deterioration of contents to be packed and maintaining their functions and properties. It is required to have a gas barrier property that blocks transmission of a gas (gas) that alters the contents.

[0003] For this reason, a packaging material using a metal foil made of a metal such as aluminum which is less affected by temperature, humidity, etc. has been generally used as a gas barrier layer for imparting gas barrier properties to the packaging material.

However, a packaging material using a metal foil made of a metal such as aluminum has an excellent gas barrier property, but has a drawback that the contents cannot be checked through the packaging material. When the packaging material is later discarded, it has the disadvantage that the packaging material must be treated as a non-combustible material. Further, when the content is packaged using this packaging material, a metal detector must be used to inspect the content. There was also a drawback that it could not be used.

Therefore, as a packaging material which overcomes these drawbacks, for example, US Pat.
As described in -28017 and the like, a vapor-deposited film made of an inorganic oxide such as silicon oxide, aluminum oxide, or tin oxide was formed on a polymer film by a forming means such as a vacuum vapor deposition method or a sputtering method. Evaporated films have been developed. These vapor-deposited films have transparency, and furthermore have a gas barrier property against oxygen, water vapor, etc., so that they are suitable as packaging materials having both transparency and gas barrier properties that cannot be obtained with metal foils and the like. It has been.

[0006]

By the way, the above-mentioned vapor-deposited film is used as a packaging material such as a packaging container or a sheet for packaging as a single vapor-deposited film in which a vapor-deposited inorganic oxide film is formed on a polymer film. Rarely used in Usually, after the deposition film is formed, various processes such as a printing process for printing characters, patterns, etc. on the film surface, a bonding process with the film, and a shaping process into a predetermined container shape are performed as post-processing. It is used as a packaging material for packaging containers and packaging sheets. Further, the packaging material may be subjected to a sterilization treatment such as boiling sterilization.

[0007] For this reason, there is a problem in that the physical properties of packaging materials made of vapor-deposited films are deteriorated by post-processing or by sterilization treatment such as boiling sterilization. For example,
When a vapor-deposited film made of an inorganic oxide is formed on a polymer film, a sealant film is attached to the polymer film, the bag is made, and then the contents are filled and boil-sterilized. There is a problem that gas is generated or the gas barrier property is reduced.

[0008] Therefore, so far, the transparency is such that the contents can be directly seen through, the high gas barrier property for blocking gases that affect the contents, and the gas barrier property even after sterilizing the boil. The actual situation is that no packaging material suitable for boil packaging has been found, which has all the boil resistance properties that there is no deterioration and no delamination or the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has high transparency, high gas barrier properties, and does not deteriorate in physical properties even after boiling sterilization. The purpose is to provide the material.

[0010]

Means for Solving the Problems To achieve the above object, the present invention provides a transparent primer comprising a mixture of an acrylic polyol and an isocyanate compound on at least one surface of a substrate made of a transparent plastic material. A layer and a deposited thin film layer composed of an inorganic oxide are sequentially laminated,
Further, the present invention provides a gas-barrier transparent laminate in which a polyolefin-based thermoplastic resin layer is laminated thereon as a seal layer.

Particularly, in the gas-barrier transparent laminate, the inorganic oxide forming the vapor-deposited thin film layer is made of aluminum oxide, silicon oxide or a mixture thereof, or the vapor-deposited thin film layer has a thickness of 5 to 300 nm. An embodiment is provided in which the transparent primer layer has a thickness of 0.01 to 2 μm.

In addition, a transparent plastic intermediate made of a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene film is provided between the vapor-deposited thin film layer of the gas-barrier transparent laminate and the polyolefin-based thermoplastic resin layer. A water-soluble polymer, (a) one or more metal alkoxides or a hydrolyzate thereof, and (b) a state in which the layers are stacked, or between the vapor-deposited thin film layer and the polyolefin-based thermoplastic resin layer. An embodiment in which a gas barrier coating layer composed of a dried coating film of an aqueous coating agent containing at least one of tin chloride, and further, the gas barrier coating layer and a transparent plastic intermediate layer are formed on the vapor-deposited thin film layer. An embodiment is provided in which the layers are sequentially laminated.

In the gas-barrier transparent laminate of the present invention, a transparent primer layer composed of a mixture of an acrylic polyol and an isocyanate compound is laminated on a transparent plastic substrate, and a vapor-deposited thin film layer composed of an inorganic oxide is laminated thereon. ing. Here, the vapor deposition thin film layer is provided as a gas barrier layer like the vapor deposition film of the conventional vapor deposition film,
Since the transparent primer layer has excellent interlayer adhesion and smoothness, the adhesion between the transparent plastic substrate and the deposited thin film layer is enhanced. Therefore, the gas-barrier transparent laminate of the present invention prevents generation of delamination due to boil sterilization and a decrease in gas-barrier property due to the occurrence of delamination. Further, the gas-barrier transparent laminate of the present invention is excellent in transparency, and becomes a highly practical packaging material satisfying boil aptitude.

In particular, in the gas-barrier transparent laminate of the present invention, a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene film is provided between the vapor-deposited thin film layer and the polyolefin-based thermoplastic resin layer. According to the aspect in which the transparent plastic intermediate layer is laminated, the mechanical strength and the thermal stability are further increased, so that the packaging bag made of the laminated body is subjected to processing such as boil sterilization and retort sterilization. The strength becomes extremely high.

Further, in the gas-barrier transparent laminate of the present invention, a water-soluble polymer and (a) one or more metal alkoxides or a hydrolyzate thereof are provided between the vapor-deposited thin film layer and the polyolefin-based thermoplastic resin layer. And (b) a gas barrier coating layer composed of a dried coating film of an aqueous coating agent containing at least one of tin chloride, and a high gas barrier equivalent to the case where an aluminum foil is provided as a gas barrier layer. Sex can be obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view illustrating one embodiment of the gas-barrier transparent laminate of the present invention.

In the gas barrier transparent laminate 10 shown in FIG. 1, a transparent primer layer 2, a deposited thin film layer 3, a gas barrier coating layer 4, a transparent plastic intermediate layer 5, and a polyolefin-based thermoplastic resin layer 6 are formed on a substrate 1. It has a structure that is sequentially laminated.

Here, the substrate 1 is formed of a transparent plastic material. The degree of transparency of the transparent plastic material forming the base material 1 is not particularly limited as long as the contents to be packaged can be confirmed, but the transparency of the vapor-deposited thin film layer 3 is utilized and the shape of the contents to be packaged is determined. To be able to recognize colors and colors accurately, the transmittance at a wavelength of 350 nm is 60%.
It is preferable that the degree is not less than about.

As such a transparent plastic material, for example, polyethylene terephthalate (PET),
Examples include polyester films such as polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, polyvinyl chloride films, polycarbonate films, polyacrylonitrile films, and polyimide films. These may be either stretched or unstretched. Further, as the transparent plastic material, a material having mechanical strength and dimensional stability is preferable. Therefore, among the films made of these transparent plastic materials, a polyethylene terephthalate film which is arbitrarily stretched in the biaxial direction is particularly preferable.

The base material 1 may contain various known additives and stabilizers, for example, an antistatic agent, an ultraviolet ray inhibitor, a plasticizer, a lubricant and the like. Further, in order to improve the adhesiveness with the transparent primer layer 2, the substrate 1 can be subjected to corona treatment, low-temperature plasma treatment, ion bombardment treatment as a pretreatment, and further to chemical treatment, solvent treatment and the like. May be.

The thickness of the substrate 1 is not particularly limited. However, the thickness of the laminate 10 including other layers is suitable as a packaging material, and the transparent primer layer 2 In consideration of workability when forming the thin film layer 3 and the gas barrier coating layer 4, it is practically preferably 3 to 200 μm, and more preferably 6 to 30 μm.

Further, from the viewpoint of mass productivity of the gas barrier transparent laminate 10, it is preferable to use a long film as the substrate 1 so that each layer can be continuously laminated thereon.

The transparent primer layer 2 laminated on the substrate 1 enhances the adhesion between the substrate 1 and the deposited thin film layer 3,
It is provided to prevent the occurrence of delamination after boiling sterilization. In the present invention, in order to achieve the object, the transparent primer layer 2 is required to be formed from a mixture of an acrylic polyol and an isocyanate compound.
That is, when a mixture of an acrylic polyol and an isocyanate compound is used as a material for forming the transparent primer layer 2, a urethane bond is formed by these reactions, and thus each of the base material 1, the transparent primer layer 2, and the vapor-deposited thin film layer 3 is formed. Adhesion between layers can be improved.

Here, as the acrylic polyol, an acrylic resin or the like using a vinyl monomer having a highly reactive hydroxy group such as hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate or acrylate as a copolymer component can be used. In consideration of the reactivity with the mixed isocyanate compound, the hydroxyl value in this case is 5
It is preferably set to 200 (KOHmg / g).

On the other hand, the isocyanate compound reacts with the acrylic polyol to form a urethane bond,
It mainly acts as a crosslinking or curing agent. Examples of the isocyanate compound include aromatic tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI), and aliphatic xylene diisocyanate (XDI) and hexadiisocyanate (HMDI).
Etc. can be used alone or as a mixture thereof.

The mixing ratio of the acrylic polyol and the isocyanate compound is not particularly limited, but if the amount of the isocyanate compound is too small, the curing may be poor. Cause problems. Therefore, the mixing ratio of the acrylic polyol and the isocyanate compound is preferably such that the NCO group derived from the isocyanate compound is not more than 50 times the OH group derived from the acrylic polyol, and in particular, the NCO group and the OH
It is preferred to mix the groups with the equivalents. Well-known methods can be used as these mixing methods, and there is no particular limitation.

The solvent used for preparing the mixture of the acrylic polyol and the isocyanate compound is not particularly limited as long as the resin formed from the mixture can be dissolved and diluted. For example, those used alone or arbitrarily in esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic hydrocarbons such as toluene and xylene can be used. Preferably, a mixture of toluene and ethyl acetate is preferable from the viewpoint of coating film processing and odor.

The mixture may contain various additives such as curing accelerators such as tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts; It is also possible to add antioxidants such as phosphites, leveling agents, flow regulators, catalysts, crosslinking reaction accelerators, fillers and the like.

The thickness of the transparent primer layer 2 is not particularly limited as long as a uniform coating film can be formed, but is generally preferably in the range of 0.01 to 2 μm. If the thickness is less than 0.01 μm, it is difficult to obtain a uniform coating film, and the adhesion may be reduced. On the other hand, when the thickness exceeds 2 μm, it is difficult to maintain flexibility of the coating film due to the thickness, and the coating film may be cracked by external factors, which is not preferable. Particularly preferred thickness of the transparent primer layer 2 is in the range of 0.05 to 0.5 μm.

The method for forming the transparent primer layer 2 is as follows.
For example, a known printing method such as an offset printing method, a gravure printing method, or a silk screen printing method, or a known coating method such as a roll coat, a knife edge coat, or a gravure coat can be used. Drying conditions after printing or coating can be the conditions generally used.

In the gas-barrier transparent laminate 10 shown in FIG. 1, the vapor-deposited thin film layer 3 laminated on the transparent primer layer 2 is composed of a vapor-deposited film of an inorganic oxide. This deposited thin film layer 3
Has transparency and gas barrier properties against oxygen, water vapor and the like. The inorganic oxide that forms the vapor-deposited thin film layer 3 is not particularly limited as long as the vapor-deposited thin film layer 3 is a transparent layer having gas barrier properties, and various inorganic oxides can be used, for example, aluminum oxide and silicon oxide. And inorganic oxides such as tin oxide, magnesium oxide, and mixtures thereof. Among these, aluminum oxide and silicon oxide are particularly preferred.

The method for forming the vapor-deposited thin film layer 3 on the transparent primer layer 2 can be based on various methods for forming a vapor-deposited film. For example, it can be formed by a normal vacuum deposition method, and other thin film forming methods such as a sputtering method, an ion plating method, and a plasma vapor deposition method (C
VD) or the like. However, in consideration of productivity, the vacuum deposition method is currently the most excellent.
As a heating means of the vacuum evaporation apparatus used in the vacuum evaporation method, an electron beam heating method, a resistance heating method, or an induction heating method is preferable. Also, the transparent primer layer 2 of the vapor-deposited thin film layer 3
It is also possible to use a plasma-assist method or an ion-beam assist method in order to improve the adhesion to the film and the denseness of the deposited thin film layer 3. In order to increase the transparency of the vapor-deposited thin film layer 3, reactive vapor deposition may be performed by blowing oxygen gas or the like during the formation of the vapor-deposited film.

The preferred thickness of the vapor-deposited thin film layer 3 depends on the type of the inorganic oxide used for its formation, etc., but is generally preferably in the range of 5 to 300 nm, more preferably 10 to 15 nm.
0 nm is more preferred. If the film thickness is less than 5 nm, it is difficult to obtain a uniform vapor-deposited film, and the film thickness becomes insufficient, so that the function as a gas barrier layer may not be sufficiently achieved. Conversely, if the film thickness exceeds 300 nm, it is difficult to maintain flexibility in the deposited film,
Cracks may occur in the deposited film due to external factors such as bending and pulling.

In the gas-barrier transparent laminate 10 of FIG. 1, the gas-barrier coating layer 4 is provided on the vapor-deposited thin-film layer 3 if necessary in order to provide the gas-barrier transparent laminate 10 with a gas barrier property as high as aluminum. It is laminated. Therefore, the formation of the gas barrier coating layer 4 is omitted depending on the use of the gas barrier transparent laminate 10 and the like.

The gas-barrier coating layer 4 for providing the gas-barrier transparent laminate 10 with a gas-barrier property as high as aluminum is composed of a water-soluble polymer and one of (a) It is preferably formed from a dried coating film of an aqueous coating agent containing at least one of the above metal alkoxide or a hydrolyzate thereof and (b) tin chloride. More specifically, a water-soluble polymer and tin chloride are mixed with an aqueous solvent (such as water or a mixture of water and alcohol).
Or dissolved in a water-soluble polymer and tin chloride in an aqueous solvent, and then coated with a solution obtained by mixing a metal alkoxide or a hydrolyzate thereof, or a metal alkoxide or A solution obtained by dissolving the hydrolyzate in an aqueous solvent is used as a coating agent. Then, by coating the coating agent on the vapor-deposited thin film layer 3 and drying by heating, the gas barrier film layer 4 that greatly improves the gas barrier property of the gas barrier transparent laminate 10 can be formed.

Next, each component contained in the coating agent will be described in more detail.

First, as the water-soluble polymer, polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, sodium alginate and the like can be used. In particular, it is preferable to use polyvinyl alcohol (hereinafter referred to as PVA) from the viewpoint of improving the gas barrier properties of the gas barrier transparent laminate of the present invention. In this case, a PVA generally obtained by saponifying polyvinyl acetate can be used, and the degree of saponification is not particularly limited. Various PVAs can be used, from so-called partially saponified PVA in which acetic acid groups remain in several tens% to complete PVA in which only several% of acetic acid groups remain.

Next, as the metal alkoxide of the component (a), tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ), triisopropoxy aluminum [Al (O-2′-C ₃ H ₇ ) ₃ ]
A general formula such as M (OR) _n (where M is Si, Ti, A
l, Zr and the like, and R is an alkyl group such as CH ₃ and C ₂ H ₅ ). Among them, tetraethoxysilane and triisopropoxyaluminum are preferable because they are relatively stable in an aqueous solvent after hydrolysis. As the component (a), a hydrolyzate of these metal alkoxides can also be used. As the tin chloride of the component (b), stannous chloride (SnCl ₂ ) and stannic chloride (SnCl ₄ ) Or mixtures thereof. Tin chloride can be used either as an anhydride or a hydrate.

One or both of the components (a) and (b) are used together with a water-soluble polymer.

The aqueous coating agent for forming the gas barrier film layer 4 includes an isocyanate compound, a silane coupling agent, a dispersant, and the like, as long as the gas barrier property is not impaired.
Known additives such as a stabilizer, a viscosity modifier, and a coloring agent can be added.

For example, as the isocyanate compound to be added to the coating agent, those having two or more isocyanate groups (NCO groups) in the molecule can be mentioned. More specifically, tolylene diisocyanate (TDI) And monomers such as triphenylmethanetriisoyanate (TTI) and tetramethylxylene diisocyanate (TMXDI), and polymers and derivatives thereof.

As a method of applying the aqueous coating agent for forming the gas barrier coating layer 4, conventionally known means such as a dipping method, a roll coating method, a screen printing method and a spray method can be used.

The thickness of the gas barrier coating layer 4 varies depending on the type of coating agent used for its formation and processing conditions, but is preferably 0.01 to 50 μm after drying. If the film thickness is less than 0.01 μm, the gas barrier properties cannot be sufficiently improved, and
When the thickness exceeds 0 μm, cracks are easily generated in the film, which is not preferable.

In the gas-barrier transparent laminate 10 shown in FIG. 1, the transparent plastic intermediate layer 5 is formed as necessary in order to increase the bag breaking strength in boiling sterilization or retort sterilization. Therefore, the gas barrier transparent laminate 1
In some cases, the transparent plastic intermediate layer 5
Is omitted.

As the constituent material of the transparent plastic intermediate layer 5 used for improving the bag breaking strength, a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene is used in view of mechanical strength and thermal stability. Preferably, a film is used. The thickness of the transparent plastic intermediate layer 5 is determined according to the material, required quality, and the like, but is generally preferably 10 to 30 μm. As a method for forming the transparent plastic intermediate layer 5, a known method such as a dry lamination method in which the above-described film is bonded using an adhesive such as a two-component curable urethane resin can be used.

In the gas-barrier transparent laminate 10 shown in FIG. 1, the polyolefin-based thermoplastic resin layer 6 is laminated as a seal layer used in an adhesive portion when the laminate 10 is formed into a bag-like package or the like. I have. Examples of the constituent material of the polyolefin-based thermoplastic resin layer 6 include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, and ethylene-acrylic acid copolymer. Polyolefin-based thermoplastic resins such as polymers, ethylene-acrylate copolymers, and metal cross-linked products thereof are used. The thickness of the polyolefin-based thermoplastic resin layer 6 is determined according to the purpose, but is generally 15 to 200.
It is preferably set to μm. As a method for forming the polyolefin-based thermoplastic resin layer 6, for example, a dry laminating method in which a film-shaped one made of the above-described polyolefin-based thermoplastic resin is bonded using an adhesive such as a two-component curable urethane resin is used. Can be.

Although the gas-barrier transparent laminate 10 shown in FIG. 1 has been described above, the gas-barrier transparent laminate of the present invention is not limited to the individual layers constituting the gas-barrier transparent laminate 10 of FIG. To have various layers.

For example, when the gas barrier transparent laminate is put to practical use as a packaging bag or the like, it is preferable to provide a printing layer on the vapor-deposited thin film layer 3 or the gas barrier coating layer.
The printing layer is composed of a conventionally used ink binder resin such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride, and various additives such as pigment, extender, plasticizer, drying agent, and stabilizer. This is a layer composed of an ink in which a character or a pattern is mixed. As a method for forming the print layer, for example, a known printing method such as an offset printing method, a gravure printing method or a silk screen printing method, or a known coating method such as a roll coat, a knife edge coat, or a gravure coat can be used. The thickness of the printing layer is usually 0.1 to
Preferably it is 2.0 μm.

Further, the gas-barrier transparent laminate of the present invention does not necessarily have to have each layer of the gas-barrier transparent laminate 10 shown in FIG. 2, a transparent primer layer 2, a vapor-deposited thin film layer 3, and a polyolefin-based thermoplastic resin layer 6 are sequentially formed on the base material 1 without the gas barrier coating layer 4 and the transparent plastic intermediate layer 5. A stacked embodiment can be adopted. Further, unlike the laminate 10c shown in FIG. 3, the gas barrier coating layer 4 is not provided,
Base material 1, transparent primer layer 2, vapor-deposited thin film layer 3, transparent plastic intermediate layer 5, polyolefin-based thermoplastic resin layer 6
4 and a laminated body 10d shown in FIG. 4 without a transparent plastic intermediate layer 5, a base material 1, a transparent primer layer 2, a vapor-deposited thin film layer 3, a gas barrier coating layer 4, and a polyolefin-based material. It is also possible to adopt a configuration in which the thermoplastic resin layers 6 are sequentially laminated.

Each of the layers constituting the gas-barrier transparent laminate described above can be formed not only on one surface of the substrate 1 but also on both surfaces.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 A gas barrier transparent laminate having the same layer structure as the gas barrier transparent laminate 10 of FIG. 1 was produced as follows.

First, a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm was used as the substrate 1, and a resin having the following composition as a transparent primer layer 2 having a thickness of 0 μm was formed on one surface thereof by a gravure coating method. .1 μm.

[Resin composition for forming transparent primer layer] Resin: acrylic polyol / isocyanate compound Compounding ratio: OH group (acryl polyol) / NCO group (isocyanate) = 1/1 (equivalent ratio) Solvent: toluene / ethyl acetate = 5/5

Next, silicon oxide was deposited on the transparent primer layer 2 to a thickness of about 40 nm by a vacuum evaporation apparatus using a resistance heating method.
To form a deposited thin film layer 3.

Further, an aqueous coating agent having the following composition was applied thereon with a bar coater and dried at 120 ° C. for 1 minute with a drier to form a gas barrier coating layer 4 having a thickness of 0.3 μm.

[Aqueous coating agent composition] The following liquid and liquid were blended at a weight ratio of 60:40. Liquid: 10.4 g of tetraethoxysilane and hydrochloric acid (0.1
N) 89.6 g was added thereto, and the mixture was stirred for 30 minutes and hydrolyzed to obtain a hydrolysis solution having a solid content of 3 wt% (in terms of SiO ₂ ). A 3 wt% solution of polyvinyl alcohol in water / isopropyl alcohol (water: isopropyl alcohol = 90: 1)
0 (weight ratio)

Next, as a transparent plastic intermediate layer 5, a biaxially stretched nylon film having a thickness of 15 μm is laminated by a dry lamination method via a two-component curable urethane-based adhesive, and further as a polyolefin-based thermoplastic resin layer 6. A low-density polyethylene film having a thickness of 40 μm was laminated by a dry lamination method via a two-component curable urethane-based adhesive to obtain a gas-barrier transparent laminate of Example.

Example 2 In Example 1, as the vapor-deposited thin film layer 3, metallic aluminum was evaporated by a vacuum vapor deposition device using an electron beam heating method, oxygen gas was introduced therein, and an aluminum oxide thin film layer having a thickness of 20 nm was formed. Except for forming, a gas-barrier transparent laminate of an example was obtained in the same manner as in Example 1.

Example 3 In Example 1, a resin having the following composition was used for forming the transparent primer layer 2 and a transparent primer layer 2 having a thickness of 0.2 μm was formed in the same manner as in Example 1. A gas barrier transparent laminate of an example was obtained.

[Resin Composition for Forming Transparent Primer Layer] Resin: acrylic polyol / isocyanate compound Compounding ratio: OH group (acrylic polyol) / NCO group (isocyanate) = 1/4 (equivalent ratio) Solvent: toluene / ethyl acetate = 5/5

Example 4 A gas-barrier transparent laminate of an example was obtained in the same manner as in Example 1 except that the transparent plastic intermediate layer 5 was not provided.

Example 5 A gas-barrier transparent laminate of an example was obtained in the same manner as in Example 1 except that the gas-barrier film layer 4 was not provided.

Comparative Example 1 A transparent laminate of a comparative example was obtained in the same manner as in Example 1 except that the transparent primer layer 2 was not provided.

Comparative Example 2 A transparent laminate was obtained in the same manner as in Example 2 except that the transparent primer layer 2 was not provided.

Evaluation A four-way pouch to be used for sterilizing boil was prepared using the laminates obtained in each of the examples and comparative examples.
g, and sterilized in boil at 90 ° C. for 30 minutes.
Evaluation items include (1) oxygen permeability before and after boiling (cc /
m ² / day), (2) Laminate strength (gr / 15 mm)
And (3) The state of occurrence of delamination after boiling by visual observation was examined or observed as follows. Table 1 shows the results.

(1) Oxygen permeability before and after boiling (cc / m ² /
day): Measuring device: Oxygen permeability measuring device manufactured by Mocon Co., Ltd. Measuring conditions: 30 ° C., 70% RH (2) Laminating strength (gr / 15 mm): Measuring device: Tensilon tensile tester Peeling speed: 300 mm / min Peeling angle: 180 ゜ (3) Delamination occurrence after boiling by visual observation: Observation of the presence or absence of floating etc. in the seal part etc.

[0069]

[Table 1] Oxygen permeability Laminate strength Appearance Before total boiling After boiling Before boiling After boiling Evaluation Example 1 0.34 0.52 410 430 ◎ ◎ Example 2 0.41 0.43 570 510 ◎ ◎ Example 3 0.38 0.47 450 420 ◎ ◎ Example 4 0.51 0.48 500 450 ○ ○ Example 5 0.78 0.92 320 330 ○ ○ Comparative Example 1 0.34 1.08 460 100 × × Comparative Example 2 0.42 0.74 540 300 × ×

From the results shown in Table 1, the laminates of Comparative Examples 1 and 2 are transparent enough to allow the contents to be directly seen through.
Insufficient gas barrier properties to block gases etc. which affect the contents, and poor boil resistance without generation of gas barrier properties and delamination after boiling. It can be seen that the laminate of Example 1 has excellent transparency, gas barrier properties, and boil resistance, and is excellent in suitability as a packaging material to be subjected to boil sterilization treatment.

[0071]

The laminate of the present invention is excellent in transparency, has high gas barrier properties comparable to aluminum foil, and has versatility. In particular, since the adhesiveness of each layer constituting the laminate is high, it is excellent in boil aptitude and the occurrence of delamination due to boil sterilization or the like is prevented. Therefore, the laminate of the present invention can be widely used in the field of packaging.

[Brief description of the drawings]

FIG. 1 is a layer configuration diagram of a gas-barrier transparent laminate of the present invention.

FIG. 2 is a layer configuration diagram of another embodiment of the gas-barrier transparent laminate of the present invention.

FIG. 3 is a layer configuration diagram of another embodiment of the gas-barrier transparent laminate of the present invention.

FIG. 4 is a layer configuration diagram of another embodiment of the gas-barrier transparent laminate of the present invention.

[Explanation of symbols]

Reference Signs List 1 base material 2 transparent primer layer 3 vapor-deposited thin film layer 4 gas barrier coating layer 5 transparent plastic intermediate layer 6 polyolefin-based thermoplastic resin layer 10, 10b, 10c, 10d gas barrier transparent laminate

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 65/40 B65D 65/40 D C23C 14/08 C23C 14/08 N (72) Inventor Tomonori Komori 1 Taito, Taito-ku, Tokyo No.5-1, Toppan Printing Co., Ltd.

Claims (9)

[Claims] 1. A transparent primer layer composed of a mixture of an acrylic polyol and an isocyanate compound and a vapor-deposited thin film layer composed of an inorganic oxide are sequentially laminated on at least one surface of a substrate composed of a transparent plastic material, and a sealing layer is further formed thereon. A gas-barrier transparent laminate, wherein a polyolefin-based thermoplastic resin layer is laminated. 2. The gas barrier transparent laminate according to claim 1, wherein the inorganic oxide forming the vapor-deposited thin film layer comprises aluminum oxide, silicon oxide, or a mixture thereof. 3. The gas-barrier transparent laminate according to claim 1, wherein the thickness of the vapor-deposited thin film layer is 5 to 300 nm. 4. The transparent primer layer having a thickness of 0.01 to 2
The gas-barrier transparent laminate according to claim 1, which has a thickness of μm. 5. A transparent plastic intermediate layer comprising a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film or a biaxially stretched polypropylene film is laminated between the vapor-deposited thin film layer and the polyolefin-based thermoplastic resin layer. Item 2. The gas barrier transparent laminate according to Item 1. 6. A gas barrier film layer is laminated between a vapor-deposited thin film layer and a polyolefin-based thermoplastic resin layer,
The gas barrier coating layer comprises a dried coating film of an aqueous coating agent containing a water-soluble polymer, and (a) at least one of a metal alkoxide or a hydrolyzate thereof and (b) tin chloride. The gas barrier transparent laminate according to claim 1. 7. A biaxially stretched nylon film between a gas barrier film layer and a polyolefin-based thermoplastic resin layer.
The gas-barrier transparent laminate according to claim 6, wherein a transparent plastic intermediate layer comprising a biaxially oriented polyethylene terephthalate film or a biaxially oriented polypropylene film is laminated. 8. The water-soluble polymer forming the gas barrier film layer comprises polyvinyl alcohol.
The gas-barrier transparent laminate according to the above. 9. The gas-barrier transparent laminate according to claim 6, wherein the metal alkoxide forming the gas-barrier film layer comprises tetraethoxysilane, triisopropoxyaluminum, or a mixture thereof.