JPH1029263A - Laminated material suitable for heat sterilization and packaging container using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated material reduced in the lowering of interlaminar close adhesive strength and the lowering of barrier properties even if heated and sterilized in a retort or a boiler and not generating a phenomenon levitating a vapor deposition layer and a packaging container. SOLUTION: A laminated material is obtained by providing a coating layer 4 composed of a water soluble polymer, metal alkoxide or a hydrolysate thereof on the vapor deposition surface of a vapor deposition film wherein a vapor deposition layer 3 composed of an inorg. compd. is provided to a heat-resistant plastic film 2 through an anchor coat layer 9 to form a barrier material 1 and providing a heat-sealable resin layer on the coating layer 4 of the barrier layer through an adhesive 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vapor deposition film provided with an inorganic compound vapor-deposited layer containing a metal oxide such as silicon oxide and aluminum oxide. The present invention relates to a laminated material which is a barrier material and has a small decrease in barrier properties after heat sterilization, and a packaging container using the laminated material.

[0002]

2. Description of the Related Art In recent years, as a barrier material in place of aluminum foil, a transparent vapor-deposited film in which a vapor-deposited layer of an inorganic compound such as silicon oxide or aluminum oxide is provided on a plastic film has been frequently used.

[0003] This vapor-deposited film has the advantages of being transparent and exhibiting an excellent barrier property in a normal state, and being capable of being heated in a microwave oven at the time of use. When the contents are filled and sealed in a packaging container consisting of, and then subjected to heat sterilization such as retort and boiling,
Deterioration of the barrier property and poor appearance were observed, and it did not reach practical use. The main causes are considered to be the adhesion strength between the deposited layer and the plastic film, the strength of the deposited layer itself, and the adhesion strength between the deposited layer and the heat-sealable resin layer.

First, as means for improving the adhesion strength between the vapor deposition layer and the plastic film, a plastic film may be provided with a corona discharge treatment, a plasma treatment and an anchor coat layer. In general, the adhesion between the vapor-deposited layer of the laminated material for heat sterilization and the heat-sealable resin layer is integrated by a dry lamination method using a two-component curable urethane adhesive having heat resistance. In this way, even when taking measures to increase the adhesion strength between the respective layers, even when heat-sterilized retort, boil and the like,
Due to the influence of moisture and the contents, the adhesion strength of the vapor-deposited layer is reduced, and when the layers are peeled off or bent, the vapor-deposited layer floats, resulting in a packaging container having poor appearance.

[0005]

SUMMARY OF THE INVENTION The present invention uses a barrier material provided with an inorganic compound vapor-deposited layer, which has attracted attention as a transparent barrier material in place of aluminum foil, and performs heat sterilization of retorts, boilers, and the like. There is little decrease in barrier properties,
Moreover, it is an object of the present invention to provide a laminated material free from a phenomenon that a vapor deposition layer floats due to bending or the like even after heat sterilization, and a packaging container using the laminated material.

[0006]

According to a first aspect of the present invention, a water-soluble polymer and a metal alkoxide or a metal alkoxide or a water-soluble polymer are deposited on a vapor-deposited surface of a heat-resistant plastic film having an inorganic compound vapor-deposited layer via an anchor coat layer. A laminated material suitable for heat sterilization, comprising at least one barrier material provided with a coating layer containing a hydrolyzate, and a heat sealing resin layer provided on the coating layer side of the barrier material.

[0007] A second invention is a barrier wherein a coating layer containing a water-soluble polymer and tin chloride is provided on a vapor-deposited surface of a vapor-deposited film provided with an inorganic compound vapor-deposited layer via a heat-resistant plastic film via an anchor coat layer. A laminate material suitable for heat sterilization, comprising at least one layer of a material and a heat-sealing resin layer provided on the coating layer side of the barrier material.

[0008] A third invention is a laminated material suitable for heat sterilization, wherein a printed layer is provided on the coating layer surface of the barrier material of the laminated material.

A fourth invention is a laminated material suitable for heat sterilization, wherein a heat buffer layer is provided between the barrier material of the laminated material and the heat-sealing resin layer.

A fifth aspect of the present invention is a laminated material suitable for heat sterilization wherein the heat-sealing resin layer of the laminated material is a non-stretched polypropylene film.

A sixth aspect of the present invention is a laminated material suitable for heat sterilization wherein the heat-sealing resin layer of the laminated material is a polyolefin film polymerized by a metaceron catalyst.

A seventh aspect of the present invention is a bag-like packaging container using the above-described laminated material.

According to an eighth aspect of the present invention, there is provided a molded packaging container using the laminated material described above as a sealing lid.

[0014] The barrier material of the present invention comprises a heat-resistant plastic film, an anchor coat layer, an inorganic compound-deposited layer, a water-soluble polymer and a metal alkoxide, or a hydrolyzate coating layer, or a water-soluble polymer. And a coating layer made of tin oxide, so that the adhesion strength between the heat-resistant plastic film and the vapor-deposited layer, and the strength of the vapor-deposited layer itself are maintained, and the heat-sealing resin layer with an adhesive is used. The adhesion strength can be sufficiently maintained.

Further, if the heat sealing layer is provided not directly on the vapor deposition layer but via the coating layer, the vapor deposition layer is protected by the coating layer when forming the heat sealing layer or forming the printing layer. Therefore, a laminated material having a small decrease in barrier properties, maintaining high gas barrier properties and water resistance, and having excellent content resistance can be obtained. Furthermore, since there are few cracks generated at the time of molding the container by heat sealing or the like at the peripheral portion, there is little change in weight even when filling and packaging contents having high permeability, and of course, the adhesion strength between layers due to components in the contents is small. The decrease is also small.

[0016]

FIG. 1 shows an example of the present invention and is a cross-sectional view for explaining the structure of a laminated material using a transparent barrier material.

In FIG. 1, reference numeral 1 denotes a barrier material;
Is a heat-resistant plastic film, 3 is an inorganic compound deposited layer, 4 is a coating layer, 5 is an adhesive, 6 is a heat sealable resin layer, and 9 is an anchor coat layer. The heat-resistant plastic film 2 is in the form of a sheet or a film, and is made of polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66).
Etc.), a plastic film or sheet having heat resistance, such as polyvinyl chloride, polyimide, or a copolymer of these polymers.

The heat-resistant plastic film 2 includes
For example, known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a colorant can be added, and are appropriately added as needed.

Further, the surface (vapor deposition surface) of the heat-resistant plastic film 2 may be subjected to a surface modification such as a corona treatment or an anchor coat treatment to provide an anchor coat layer 9. Specific examples of the material used for the anchor coat layer 9 include one type of isocyanate-based resin, epoxy resin, melamine resin, and acrylic resin, or a mixture of two or more types. Among the acrylic resins, acrylic polyols can be preferably used. Further, the thickness of the anchor coat layer varies depending on the type of the anchor coat agent, but may be in the range of 0.1 to 10 μm after drying.

The inorganic compound deposition layer 3 is made of an oxide, nitride, or the like of silicon, aluminum, titanium, zirconium, tin, or the like.
It is composed of a simple substance of fluoride or a composite thereof, and is formed by a vacuum deposition method, a sputtering method, a plasma vapor deposition method (CV).
D method) or the like. The thickness of the inorganic compound vapor-deposited layer 3 is in the range of 100 to 2000 °, preferably in the range of 400 to 1000 °. Further, the composition of the vapor deposition layer is not particularly limited by heat sterilization at a low temperature, but for sterilization at a high temperature such as a retort, a simple substance of aluminum oxide or a composition containing aluminum oxide as a main component is preferable.

The coating layer 4 is mainly composed of an aqueous solution containing a water-soluble polymer and at least one of (a) one or more metal alkoxides and hydrolysates thereof, and (b) tin chloride, or a mixed solution of water / alcohol. And a coating agent. A water-soluble polymer and tin chloride are converted to an aqueous system (water or water /
A mixture of a solution dissolved with a solvent or a solution obtained by directly treating a metal alkoxide with the solvent or a treatment in which the metal alkoxide is previously hydrolyzed is coated on the inorganic compound vapor-deposited layer 3 on the heat-resistant plastic film 2. , Heated and dried. Each component contained in the coating agent will be described in detail below.

The water-soluble polymer used for the coating agent in the present invention includes polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, sodium alginate and the like. In particular, when polyvinyl alcohol (PVA) is used as the coating agent for the gas barrier laminate of the present invention, the gas barrier properties are most excellent. The PVA referred to here is generally obtained by saponifying polyvinyl acetate, and ranges from so-called partially saponified PVA in which tens of percent of acetic acid groups remain to fully saponified PVA in which only a few percent of acetic acid groups remain. Including
There is no particular limitation.

In addition, tin chloride is prepared from stannous chloride (SnC).
l ₂ ), stannic chloride (SnCl ₄ ), or a mixture thereof, and either an anhydride or a hydrate can be used.

Further, the metal alkoxide is a general formula such as tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ], triisopropoxy aluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], M (OR) _n (M; metal such as Si, Ti, Al, Zr, R; CH ₃ ,
(An alkyl group such as C ₂ H ₅ ). Among them, tetraethoxysilane and triisopropoxyaluminum are preferable because they are relatively stable in an aqueous solvent after hydrolysis.

Each of the above-mentioned components can be added to the coating agent alone or in combination of several components. Further, as long as the barrier properties of the coating agent are not impaired, isocyanate compounds, silane coupling agents, dispersants, and stabilizers Known additives such as a viscosity modifier and a colorant can be added.

For example, an isocyanate compound to be added to a coating agent has two or more isocyanate groups (NCO groups) in its molecule, such as tolylene diisocyanate (TDI), triphenylmethane triisocyanate (TTI), There are monomers such as tetramethylxylene diisocyanate (TMXDI), and polymers and derivatives thereof.

As a method for applying the coating agent, conventionally known means such as a commonly used dipping method, roll coating method, screen printing method, spray method and the like are used. Although the thickness of the film varies depending on the type of the coating agent, the thickness after drying may be in the range of about 0.01 to 100 μm. When the thickness is 50 μm or more, cracks are easily generated in the film. It is desirable that the thickness be 50 μm.

The barrier material having the above-described structure is provided in one layer in the laminated material of the present invention. If a higher barrier property is required, a structure in which two or more barrier materials are provided can be employed.

The heat-sealable resin layer 6 can be used according to the purpose if it is a resin having heat-sealability, such as polyethylene, polypropylene, ethylene copolymer, and saturated polyester. When required, a non-stretched polypropylene film, and a polyrefine synthesized using a metaceron catalyst as a material having a low resin odor of the contents are preferable.

The heat-sealable resin layer 6 is preferably provided by laminating a film-formed material via an adhesive 5. It is also possible to laminate the molten resin by direct extrusion coating. As the adhesive used here, a two-component or one-component curable urethane adhesive having heat resistance is preferable.

The laminated material of the present invention is a laminated material in which the printing layer 7 is provided directly on the coating layer 3 as shown in FIG. As described above, the printing layer 7 can be provided directly on the barrier material 1, and as the ink used for the printing layer 7, a urethane-based ink having heat resistance and excellent adhesion strength is preferable.

Further, as shown in FIG. 3, the laminated material of the present invention is a laminated material in which a thermal buffer layer 8 is provided on a coating layer 3 of a barrier material 1 with an adhesive 5 interposed therebetween. By providing the heat buffer layer 8 in this manner, when heat sterilization of a retort, a boil or the like is performed, the influence of heat is small, and mechanical strength such as barrier properties and drop strength can be maintained. As the film used for the thermal buffer layer 8, a biaxially stretched nylon film and a biaxially stretched polyethylene terephthalate film are preferable.

This laminated material is made of a heat-sealable resin layer 6.
Can be formed into a bag-shaped packaging container such as a pillow packaging bag, a four-sided sealing bag, a three-sided sealing bag, a gusset-shaped bag, or a standing pouch. Further, as shown in FIG. 4, this laminated material can be used as the sealing lid 11 of the molded packaging container 10.

[0034]

EXAMPLES Examples of the present invention will be described below more specifically. Example 1 An anchor coat layer having a thickness of about 0.1 μm and comprising the following components was provided on one surface of a polyethylene terephthalate (PET) film having a thickness of 12 μm, and SiO (silicon oxide) was used as an evaporation source on the upper surface thereof. By a vacuum deposition method using a resistance heating method, a deposition layer having a thickness of 400 ° is formed,
Further, a coating liquid having the following composition was applied by a bar coater, and dried at 120 ° C. for 1 minute with a drier, to obtain a thickness of about 0.1 mm.
A coating layer of 5 μm was formed. Then, the coating layer was coated with a urethane-based two-component curable adhesive (A-515, manufactured by Takeda Pharmaceutical Co., Ltd.) by a gravure method at 4 g / m ^2, and the thickness was 1
A low-density polyethylene having a thickness of 40 μm was laminated on a 5 μm biaxially stretched nylon film by a dry lamination method, and also by a dry lamination method using the same adhesive as above to obtain a predetermined laminated material.

Component of anchor coat layer A composition in which a saturated polyester and an isocyanate resin are mixed at a ratio of -OH group to -NCO group of 1: 4.

10. Components of coating liquid Tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ]
89.6 g of hydrochloric acid (0.1N) was added to 4 g, and the mixture was stirred for 30 minutes and hydrolyzed to obtain a hydrolysis solution (A) having a solid content of 3 wt% (in terms of SiO ₂ ), and a polyvinyl alcohol of 3.0%.
A composition obtained by mixing a wt% water / isopropyl alcohol (90/10) solution (B).

The oxygen permeability is measured by the Mocon method,
0.30 cc / m ² · day · atm (30 ° C, 70
% RH), and the water vapor transmission rate was measured by the Mocon method, and was 0.25 g / m ² · day (40 ° C., 90% R
H).

<Comparative Example 1> A test similar to that of Example 1 was performed on a laminated material having the same structure as that of Example 1 except that the coating layer of Example 1 was not provided. Oxygen permeability is 1.1c
c / m ² · day · atm, and the water vapor permeability is
It was 1.2 g / m ² · day.

Comparative Example 2 A laminated material having the same structure as in Example 1 except that the anchor coat layer of Example 1 was not provided was used. The oxygen permeability of this laminated material is 0.31 cc / m ²
・ Day ・ atm, water vapor permeability is 0.24g
/ M ² · day.

<Heat Sterilization Test 1> Using the laminated materials of Example 1 and Comparative Example 2 having good barrier properties, each laminated material was sealed on three sides to form a bag-like package with one side opened. A container was manufactured. In each of these bag-shaped packaging containers,
After filling with tap water heated to 90 ° C. and sealing the opening,
Boil sterilization was performed at 95 ° C for 60 minutes. Further, in order to evaluate the presence or absence of floating at the bent portion due to bending or the like, the packaging container was folded in two, and sterilized in boil under the same conditions while being fixed with the clip. And before and after sterilization, PET
The adhesion strength between layers of the film and the low-density polyethylene film, oxygen permeability, and appearance evaluation by bending after boiling sterilization were measured and observed by the following methods. Table 1 shows the results. Adhesion strength 強度 The strength when stripped 15 mm wide and peeled 180 degrees. The display unit is g / m ² Oxygen permeability ‥‥ Mocon method. The display unit is cc / m ² · day · atm Appearance evaluation ‥‥ ○: wrinkles due to bending, but floating of vapor deposition layer cannot be confirmed ×: floating of vapor deposition layer at bending part due to bending can be confirmed

[0041]

[Table 1]

Example 2 A laminated material having the same structure as in Example 1 was used except that the vapor-deposited layer of Example 1 was made of aluminum oxide and the heat-sealing resin layer was made of a non-stretched polypropylene film having a thickness of 60 μm. . The oxygen permeability of this laminated material was 0.30 cc / m ² · day · atm, and the water vapor permeability was 0.24 g / m ² · day.

<Comparative Example 3> A laminated material having the same structure as in Example 2 except that the anchor coat layer of Example 2 was not provided was used. The oxygen permeability of this laminated material is 0.33 cc / m ²
・ Day ・ atm, water vapor permeability is 0.25g / m ²・
It was day.

<Heat Sterilization Test 2> Example 2 and Comparative Example 3
Each of the laminated materials was sealed on three sides to produce a bag-shaped packaging container having one side opened. Each of the bag-like packaging containers is filled with tap water heated to 90 ° C., the opening is sealed, and then 20 ° C. at 120 ° C.
The retort sterilization was performed for minutes. Further, in order to evaluate the presence or absence of floating at the bent portion due to bending or the like, the packaging container was folded in two, and sterilized in boil under the same conditions while being fixed with the clip. Then, before and after the sterilization, the adhesion between the PET film and the low-density polyethylene film, the oxygen permeability, and the appearance evaluation by bending after the boil sterilization were measured and observed in the same manner as in the heat sterilization test 1. Table 2 shows the results.
Shown in

[0045]

[Table 2]

<Example 3> Example 3 was repeated except that a resin in which an acrylic polyol resin and an isocyanate resin were mixed such that the ratio of -OH groups to -NCO groups was 1: 4 was used for the anchor coat layer. A test similar to that of Example 1 was performed on the laminated material having the same configuration as that of Example 1. The oxygen permeability was 0.40 cc / m ² · day · atm, and the water vapor permeability was 0.24 g / m ² · day.

Comparative Example 4 A laminated material having the same structure as in Example 3 except that the anchor coat layer of Example 3 was not provided was used. The oxygen permeability of this laminated material is 0.50 cc / m ^2.
day · atm, and the water vapor permeability is 0.26 g / m
It was ² days.

<Heat Sterilization Test 3> Example 3 and Comparative Example 4
Each of the laminated materials was sealed on three sides to produce a bag-shaped packaging container having one side opened. Each of the bag-like packaging containers was subjected to a heat sterilization test 1
Boil sterilization was performed in the same manner as described above, and the same evaluation was performed. Table 3 shows the results.

[0049]

[Table 3]

[0050]

According to the present invention having the above constitution, the strength and performance of the deposited layer of the inorganic compound itself can be maintained, and the oxygen permeability after heat sterilization is 1.0 cc / m ² · day · atm or less. Sex can be maintained.

When a laminated material is used, a coating layer is provided on the deposited layer of the barrier material, so that printing and laminating are not performed directly on the surface of the deposited layer. There is little decrease in sex.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one example of a laminated material of the present invention.

FIG. 2 is a sectional view showing an example of another laminated material of the present invention.

FIG. 3 is a cross-sectional view showing a laminated material using another material of the present invention.

FIG. 4 is a cross-sectional view illustrating an example of a molded packaging container using the laminated material of the present invention.

[Explanation of symbols]

 1 barrier material 2 heat-resistant plastic film 3 vapor-deposited layer 4 coating layer 5 adhesive 6 heat-sealable resin layer 7 printing layer 8 thermal buffer layer 9 anchor Coat layer 10 Molded packaging container 11 Sealing lid

Claims (8)

[Claims] 1. A coating layer containing a water-soluble polymer and a metal alkoxide or a hydrolyzate thereof is provided on an evaporation surface of an evaporation film provided with an inorganic compound evaporation layer via an anchor coating layer on a heat-resistant plastic film. A laminated material suitable for heat sterilization, comprising at least one layer of a barrier material and a heat-sealing resin layer provided on the coating layer side of the barrier material. 2. A barrier material having a coating layer containing a water-soluble polymer and tin chloride on a vapor-deposited surface of a vapor-deposited film provided with an inorganic compound vapor-deposited layer via an anchor coat layer on a heat-resistant plastic film. A laminated material suitable for heat sterilization, comprising a layer and a heat-sealing resin layer provided on the coating layer side of the barrier material. 3. The laminated material suitable for heat sterilization according to claim 1, wherein a printed layer is provided on the coating layer surface of the barrier material. 4. The laminated material suitable for heat sterilization according to claim 1, wherein a heat buffer layer is provided between the barrier material and the heat-sealing resin layer. 5. The laminated material suitable for heat sterilization according to claim 1, wherein the heat-sealable resin layer comprises a non-stretched polypropylene film. 6. The laminated material suitable for heat sterilization according to claim 1, wherein the heat-sealing resin layer comprises a polyolefin film polymerized by a metallocene catalyst. 7. A bag-like packaging container using the laminated material according to any one of claims 1 to 6. 8. A molded packaging container using the laminated material according to any one of claims 1 to 6 for a sealing lid.