JPH11198280A - Laminated body and method for manufacturing the same - Google Patents

Abstract

(57) Abstract: A barrier laminate having excellent lamination strength in which a barrier layer and a sealant layer each having a thin film deposition layer made of an inorganic oxide formed on a plastic substrate are laminated without using an adhesive. The object is to provide a body and a method for its manufacture. SOLUTION: A thin film deposition layer made of an inorganic oxide is formed on a plastic substrate, and a film-like molten polyethylene having one surface activated is opposed to the vapor deposition layer on one side of the surface of which the activation treatment is performed. The laminate is characterized in that the laminate is extruded and the deposited layer and polyethylene are laminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate for packaging in which a barrier layer and a sealant layer are formed on a base material, and more particularly to a barrier having a thin film deposition layer made of an inorganic oxide formed on a plastic base material. The present invention relates to a barrier laminate comprising a layer and a sealant layer and a method for producing the same.

[0002]

2. Description of the Related Art Generally, packaging materials include a base material for imparting mechanical strength during storage and transportation, and a sealant layer made of a thermoplastic resin for heat sealing the contents in a package. Composed of As the substrate, paper, a biaxially oriented polyester film, a biaxially oriented nylon film, a biaxially oriented polypropylene film, or the like is used. Examples of the sealant layer include thermoplastic resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and polypropylene. Furthermore, in order to add a function as a package, a plurality of the base materials are laminated,
An ethylene-vinyl alcohol copolymer film, a vinylidene chloride film, an aluminum foil or the like is used in a laminated state. Furthermore, as a plastic substrate on which a thin film layer composed of an inorganic oxide is deposited, it has excellent characteristics such as excellent oxygen barrier properties and water vapor barrier properties, as well as transparency, and is widely used as a packaging material for various contents. I have.

[0003] In a method of laminating a large number of these base materials and sealant layers to form a laminate, a film for the base material and a sealant layer is prepared in advance, and one of the films is made of polyester, polyurethane, or polyol. Examples of the method include dry lamination in which an adhesive such as a system is applied and laminated, and non-sol lamination using an adhesive composed of an elastomer, a petroleum resin, or the like. In addition, an extrusion lamination is performed in which a thermoplastic resin serving as a sealant layer is melted in an extruder, which is melted from a T-die, and is applied and laminated on a base material to which an anchor coating agent having an adhesive as a main component is previously applied. And methods such as neem.

However, all of these methods require a step of applying an adhesive or an anchor coating agent to a substrate to be laminated, and in order to sufficiently solidify the adhesive or the anchor coating agent, the method after lamination is required. It has the disadvantage of requiring heat treatment. Further, a solvent is required to apply the adhesive or the anchor coat agent to the film, and the film has a defect that the quality of the multilayer structure tends to be defective due to unevenness in the application step. Also,
The inclusion of the adhesive layer in the laminate also has the drawback that the odor of the adhesive and the residual solvent are generated as the odor of the package. Further, when using a plastic substrate on which a thin film layer made of an inorganic oxide is deposited as a substrate,
Due to the effect of the anchor coating treatment step and the solvent at that time, the barrier properties against oxygen and water may be reduced, which has been a problem.

On the other hand, as a method without using an adhesive or an anchor coat agent, there is a method of extruding and laminating an adhesive resin such as a copolymer of ethylene and acrylic acid or a resin containing an adhesive on a substrate. It has been implemented. However, the adhesive resin is expensive, has a peculiar odor, and has disadvantages in production, such as being difficult to be exchanged with another resin because it easily remains in the extruder.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method of laminating a barrier layer in which a thin film deposition layer made of an inorganic oxide is formed on a plastic substrate and a sealant layer without using an adhesive. An object of the present invention is to provide a barrier laminate having excellent laminate strength and a method for producing the same.

[0007]

The present invention can solve the problem by the following means. That is, the invention according to claim 1 is a method of forming a thin film vapor-deposited layer made of an inorganic oxide on a plastic substrate and activating the surface of the thin film vapor-deposited layer on the surface of the vapor-deposited layer. A laminate, wherein polyethylene is extruded so as to face the vapor-deposited layer, and the vapor-deposited layer and polyethylene are laminated.

According to a second aspect of the present invention, in the laminate according to the first aspect, the surface of the deposition layer is activated by a corona treatment or a plasma treatment.

According to a third aspect of the present invention, in the laminate according to the first aspect, the surface of the polyethylene is activated by an ozone treatment.

According to a fourth aspect of the present invention, in the laminate according to the first aspect, the inorganic oxide is aluminum oxide,
It is characterized by being silicon oxide or a mixture thereof.

According to a fifth aspect of the present invention, in the laminate of the first aspect, the polyethylene is a copolymer of ethylene and a comonomer selected from butene-1, hexene-1, and octene-1. It is a low-density polyethylene chain.

According to a sixth aspect of the present invention, in the laminate according to the first or fifth aspect, the density of the polyethylene is:
The range is 0.870 to 0.925 g / cm3.

[0013] The invention according to claim 7 is the invention according to claims 1, 5,
7. The laminate according to claim 6, wherein the polyethylene is polymerized with a single-site catalyst.

According to the present invention, a thin film deposition layer formed of an inorganic oxide is formed on a plastic substrate, and the surface of the vapor deposition layer having a surface activated is melted into a film-like form extruded by an extruder. One side of polyethylene is extruded so that the activated polyethylene surface faces the vapor-deposited layer between the air gaps from the T-die to the lamination, and the vapor-deposited layer and polyethylene are extruded and laminated. A method for manufacturing a laminate.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As a plastic substrate for forming a thin film deposition layer comprising an inorganic oxide of the present invention, polyethylene, polypropylene, polyethylene terephthalate,
Unstretched or stretched plastic films such as polyethylene naphthalate, polystyrene, polyamide, and polyacrylonitrile can be used.

The inorganic oxide forming the thin film deposition layer of the present invention comprises a deposition film of an inorganic oxide such as aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof, and has transparency. Any material having gas barrier properties such as oxygen and water vapor may be used. In particular, aluminum oxide and silicon oxide are preferable.

Although the optimum conditions for the thickness of the thin film deposited layer vary depending on the type and composition of the inorganic compound used, it is generally desirable that the thickness be in the range of 5 to 300 nm, and the value is appropriately selected. However, if the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved. On the other hand, if the thickness exceeds 300 nm, flexibility cannot be maintained in the thin film, and the thin film may be cracked due to external factors such as bending and stretching after the film is formed. Preferably, 1
It is in the range of 0-150 nm.

As a method of forming a thin film deposition layer made of an inorganic oxide, it can be formed by a usual vacuum deposition method. Other methods include a sputtering method, an ion plating method, and a plasma vapor deposition method (CVD). It can also be used. However, in consideration of productivity, the vacuum deposition method is currently the most excellent. The heating means of the vacuum evaporation apparatus by the vacuum evaporation method is preferably an electron beam heating method, a resistance heating method, or an induction heating method. In order to improve the adhesion between the thin film and the base material and to improve the denseness of the thin film, a plasma assist method is used. It is also possible to use a method or an ion beam assist method. In addition, in order to increase the transparency of the deposited film, a reactive evaporation method in which oxygen gas or the like is blown in the deposition may be used.

Further, a primer layer such as a polyester resin or a polyurethane resin is provided on a plastic substrate to form the thin film layer, or a water-soluble layer for protecting the thin film is formed on the inorganic oxide thin film layer. An overcoat layer containing a polymer as a main component can be provided as necessary.

The surface-treated layer of the vapor-deposited layer can be formed by a dry process such as corona treatment, plasma treatment, electron beam irradiation, or ultraviolet irradiation. Can be generated. Among these surface treatments, corona treatment can perform highly active surface treatment with a simple device, and plasma treatment has a high degree of freedom by introducing a gas such as oxygen, argon, ethylene, or propylene. Processing can be performed, which is preferable.

The polyethylene that can be used in the present invention includes low-density polyethylene, medium-density polyethylene,
High-density polyethylene and linear low-density polyethylene can be used. Among them, linear low-density polyethylene is preferable because a strong laminate strength can be obtained. Further, the above polyethylene, if necessary, an antioxidant, a lubricant,
Additives such as anti-blocking agents, antistatic agents, anti-fogging agents and the like can be added.

The linear low-density polyethylene includes propene, butene-1, hexene-1, octene-1,4
-Copolymerization with ethylene selected from methyl-pentene-1 is inexpensive and preferable, and particularly has a density of 0.870 g / c.
m3 or more and 0.925 g / cm3 or less.
It is preferably in the range of 89 to 0.915 g / cm3. Further, as the polyethylene, polyethylene polymerized by a single-site catalyst such as a metallocene catalyst having a small amount of low molecular weight components that cause odor is preferable.

The laminate of the present invention can be manufactured by a general extrusion laminating apparatus comprising an unwinding section of a substrate, a surface treatment section of the substrate, a laminating section, a winding section, an extruder and a T-die. . That is, the plastic substrate on which the thin film layer made of the inorganic oxide is deposited is sent out from the unwinding section,
Next, in the surface treatment section, the vapor deposition side of the plastic substrate can be subjected to surface treatment by a dry process such as corona treatment, plasma treatment, electron beam irradiation, or ultraviolet irradiation. Then
In the laminating section, it can be laminated with polyethylene melted in an extruder and extruded from a T-die. Ozone gas can be sprayed on the lamination side of the molten polyethylene film between the air gap from the T die to the lamination to form an oxide layer on the surface of the polyethylene film. Further, the laminate is wound up at a winding section. If the temperature of the molten polyethylene in the extruder and the T-die is too low, the processability of the polyethylene is deteriorated, and if it is too high, the polyethylene itself is deteriorated.
It is preferred that the temperature be in the range of from 0 ° C to 310 ° C.

The concentration of the ozone gas used in the ozone treatment is preferably 5 g / Nm3 or more and 60 g / Nm3 or less, and is preferably in the range of 15 g / Nm3 to 50 g / Nm3. The flow rate of the ozone gas is adjusted by the width of the extruded T-die.
/ Min to 5 L / min.

[0025]

A thin film vapor-deposited layer made of an inorganic oxide is formed on a plastic substrate, and the surface of the vapor-deposited layer is activated by corona treatment or plasma treatment. One side is T
Between the air gap from the die to the lamination,
Ozone gas is blown out and the activated polyethylene is extruded so that the surface of the polyethylene faces the vapor-deposited layer, and the vapor-deposited layer and the polyethylene are laminated by extrusion. By the above operation, active chemical species are generated on the surface of the vapor-deposited layer on the substrate subjected to the activation treatment and on the surface of the polyethylene, and are bonded, so that a laminate having a strong laminate strength without using an anchor coating agent is used. The body is obtained.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

Example 1 A 12 μm-thick biaxially stretched polyethylene terephthalate (PET) film was used as a substrate on one side by a resistance heating type vacuum evaporation apparatus.
Silicon oxide was deposited to a thickness of about 40 nm to form an inorganic oxide thin film layer, and a plastic substrate of the present invention was obtained. The base material is subjected to a corona surface treatment on the vapor deposition layer side by a corona treatment machine installed on a line of an extrusion laminator, and then low-density polyethylene M14P (manufactured by Mitsui Petrochemical Co., density 0.919 g / cm3, MFR5. 1) was extruded from a T-die at 300 ° C., and 35 g under the T-die.
A laminate of the present invention was produced by treating the polyethylene-laminated side with ozone gas having a concentration of / Nm3 and laminating the surface-treated side of the plastic substrate and the ozone-treated side of polyethylene.

<Example 2> In Example 1, a linear low-density polyethylene polymerized by a single-site catalyst as a polyethylene (Evolu SP manufactured by Mitsui Petrochemical Co., Ltd.)
A laminate was produced in the same manner except that the extrusion temperature was 1540 (density 0.915 g / cm3) and the extrusion temperature was 290 ° C.

Example 3 A laminate was produced in the same manner as in Example 1, except that aluminum oxide was used as the inorganic oxide, and plasma surface treatment was performed in a mixed gas of helium gas and ethylene gas.

Comparative Example 1 A laminate was produced in the same manner as in Example 2 except that ozone gas was not used.

Comparative Example 2 A laminate was produced in the same manner as in Example 2 except that the corona surface treatment was not performed on the substrate side.

The above-prepared laminate is 15 mm wide.
And a tensile tester with a pulling speed of 100m
The lamination strength of the substrate and the linear low-density polyethylene was measured at a speed of m / min, and the results in Table 1 were obtained.
From this result, it is clear that the laminate of the present invention has excellent lamination strength.

[0033]

[Table 1]

[0034]

According to the present invention, a laminate composed of a barrier layer in which a thin film deposition layer composed of an inorganic oxide is formed on a plastic substrate and a sealant layer can be laminated without using an anchor coating agent. The present invention can provide a laminate having excellent lamination strength, which is uniform in quality and does not contain an odor of an anchor coat agent or a solvent and is particularly suitable for a packaging material for food, and a method for producing the same.

Claims (8)

[Claims] 1. A thin film vapor-deposited layer made of an inorganic oxide is formed on a plastic substrate, and the surface of the vapor-deposited layer having been subjected to an activation treatment is coated with a film-like molten polyethylene having one surface activated by the vapor-deposited layer. A laminate characterized by being extruded so as to face each other and laminating the vapor-deposited layer and polyethylene. 2. The laminate according to claim 1, wherein the surface of the vapor-deposited layer has been subjected to an activation treatment by corona treatment or plasma treatment. 3. The method according to claim 1, wherein the surface of the polyethylene is activated by an ozone treatment.
The laminate according to the above. 4. The laminate according to claim 1, wherein said inorganic oxide is aluminum oxide, silicon oxide or a mixture thereof. 5. The method according to claim 1, wherein the polyethylene is a linear low-density polyethylene which is a copolymer of ethylene and a comonomer selected from butene-1, hexene-1, and octene-1. Laminate. 6. The laminate according to claim 1, wherein the density of the polyethylene is in a range of 0.870 to 0.925 g / cm 3. 7. The method according to claim 1, wherein said polyethylene is polymerized by a single-site catalyst.
A laminate according to any of the preceding claims. 8. A thin film deposition layer made of an inorganic oxide is formed on a plastic substrate, and one surface of a film-like molten polyethylene extruded by an extruder is placed on a surface of the vapor deposition layer having a surface activated by a T-die. A method for producing a laminate, comprising extruding the activated polyethylene surface so as to face the vapor-deposited layer and extruding and laminating the polyethylene between the vapor-deposited layer and the air-gap between the air gaps until lamination.