JP2015051632A - Laminate and food packaging container and container for microwave oven using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate having good adhesiveness between a substrate and a resin and having excellent gas barrier properties, aroma retention, heat resistance and moisture-proof properties and to provide a food packaging container and a container for a microwave oven using the same.SOLUTION: There is provided a laminate in which a polyethylene resin layer (I) composed of the following polyethylene-based resin composition (C) is formed on one surface of a base material mainly containing paper and a polyethyleneterephthalate resin layer (II) is laminated on the polyethylene resin layer (I). (C) A polyethylene-based resin composition having the following properties of (c-1), in which in the elution curve obtained by a temperature-rising elution fractionation method using o-dichlorobenzene, the ratio of the elute at 80°C or less is 28 wt.% or more.

Description

  The present invention provides a laminate excellent in gas barrier properties, fragrance retention, heat resistance, and moisture resistance, and a food packaging container and a microwave oven using the same, which have good adhesion to a substrate mainly composed of paper. Concerning the container.

Conventionally, in order to provide various functions, it is widely performed to laminate a thermoplastic resin. In particular, in the production of processed paper laminated with polyethylene, polyethylene is frequently used as a packaging or container material because of its excellent moldability and adhesiveness to paper.
However, since polyethylene has insufficient gas barrier properties, it is unsuitable in the field of food packaging containers and the like that require gas barrier properties and fragrance retention properties.
On the other hand, in a field that requires fragrance retention and heat resistance, a material obtained by laminating polyethylene terephthalate (PET) on a base material has been used. However, when PET is to be laminated on paper, it is difficult to perform stable processing, and thickness unevenness occurs, or only processed paper with insufficient adhesion to the substrate can be obtained. was there.

In order to solve the problem of adhesion between the base material and PET, the following method is disclosed.
For example, in Patent Document 1, a first layer made of PET having a specific density or a resin containing PET as a main component is disposed on a paper base material without using an adhesive layer, and the first layer is specified on the first layer. It is disclosed that the adhesiveness is improved by a multilayer polyester-based laminated paper characterized in that a second layer made of a PET copolymer resin having a density of 1 is disposed.
Moreover, in patent document 2, in the method of carrying out extrusion coating of polyester to a fiber base material, polyester which was excellent in interlayer adhesiveness by carrying out extrusion coating on specific conditions using polyester of specific melt viscosity ratio and intrinsic viscosity. It is disclosed that processed paper can be manufactured stably.
However, the adhesion between the substrate and PET is inferior to the adhesion between the substrate and polyolefin, and there is room for improvement as a material. Further, when PET is directly coated, although it has excellent fragrance retention, it has poor room for moisture resistance as compared with the case where polyethylene is laminated, so there is room for improvement.

Japanese Patent No. 3917888 Japanese Patent No. 3749000

  In view of the above-mentioned problems, the object of the present invention is to improve the adhesiveness of a laminate having a base material and having a resin layer of polyethylene and polyethylene terephthalate, each of which has been considered to have poor adhesion to each other. An object of the present invention is to provide a laminate having good adhesion between a material and a resin and excellent gas barrier properties, aroma retention, heat resistance and moisture resistance, and a food packaging container and a microwave oven container using the same.

  As a result of intensive studies to solve the above problems, the inventor of the present invention has a polyethylene resin layer (I) comprising a polyethylene-based resin composition (C) having a certain property on one surface of a paper-based substrate. It was found that the above problems can be solved by laminating a polyethylene terephthalate resin layer (II) thereon, and the present invention was completed.

That is, according to the first invention of the present application, a polyethylene resin layer (I) composed of the following polyethylene resin composition (C) is formed on one surface of a base material mainly composed of paper, on which A laminated body characterized by laminating a polyethylene terephthalate resin layer (II) is provided.
(C) Polyethylene resin composition having the following properties (c-1) (c-1) In an elution curve obtained by temperature-elution elution fractionation (TREF) with orthodichlorobenzene, the proportion of eluate of 80 ° C. or less is 28% by weight or more

Furthermore, according to the second invention of the present application, in the first invention, there is provided a laminate in which the polyethylene resin composition (C) is a polyethylene resin composition having the property (c-2). Is done.
(C-2) The test temperature is 23 ° C. and the density according to JIS-K7112 is 0.910 to 0.940 g / cm ^3.

  Furthermore, according to the third invention of the present application, the polyethylene terephthalate resin layer (II) is directly formed on the polyethylene resin layer (I) by extrusion laminating. A laminate according to the invention is provided.

Furthermore, according to the fourth invention of the present application, in any one of the first to third inventions, the polyethylene resin composition (C) comprises the following polyethylene resin (A) and polyethylene resin (B). A laminate according to claim 1 is provided.
(A) Polyethylene resin having the following properties (a-1) (a-1) Test temperature 23 ° C., density in accordance with JIS-K7112 is 0.880 / cm ³ or more and less than 0.930 g / cm ³ ( B) Polyethylene resin having the following properties (b-1) (b-1) Test temperature 23 ° C., density in accordance with JIS-K7112 is 0.930 g / cm ³ or more and 0.970 g / cm ³ or less

According to the fifth invention of the present application, in any one of the first to fourth inventions, the polyethylene resin composition (C) is a polyethylene resin composition having the property (c-1 ′). The described laminate is provided.
(C-1 ′) TREF 80 ° C. or lower eluate ratio is 28 wt% or more and 99.5 wt% or less According to the sixth invention of the present application, the polyethylene resin composition (C) is (c-1 ″). The laminate according to any one of the first to fifth inventions, which is a polyethylene resin composition having the properties of
(C-1 ″) TREF 80 ° C. or lower eluate ratio is 50 wt% or more and 99.5 wt% or less According to the seventh invention of the present application, the polyethylene resin composition (C) is (c-1 ′ The laminate according to any one of claims 1 to 6, which is a polyethylene resin composition having the property '').
(C-1 ′ ″) TREF 80 ° C. or less The eluate ratio is 57 wt% or more and 99.5 wt% or less.

According to the eighth invention of the present application, in the fourth invention, there is provided a laminate characterized in that the polyethylene resin (A) is high-pressure radical polymerization polyethylene.
On the other hand, according to the ninth invention of the present invention, in the fourth invention, the polyethylene resin (A) is a high-pressure radical polymerization polyethylene (A ′) and an ethylene α-olefin copolymer (A ″). A laminate comprising a mixture is provided.

  Furthermore, according to the tenth invention of the present application, in any one of the first to ninth inventions, the polyethylene terephthalate resin layer (II) is laminated on the polyethylene resin layer (I) in the molding process. There is provided a laminate characterized in that the surface of the polyethylene resin layer (I) is subjected to corona treatment.

Furthermore, according to the eleventh invention of the present application, according to any one of the first to tenth inventions, a food packaging container obtained from the laminate is provided.
According to a twelfth aspect of the present invention, there is provided a microwave oven container obtained from the laminate according to any one of the first to tenth aspects.

  According to the present invention, there was obtained a laminate having no problem in adhesion and excellent in gas barrier properties, aroma retention, heat resistance, and moisture resistance. In addition, by using this laminate, it is possible to stably obtain a food packaging container and a microwave oven container that are excellent in gas barrier properties, aroma retention, heat resistance, and moisture resistance.

It is the graph which showed the integral elution curve obtained by the temperature rising elution fractionation (TREF) by the ortho dichlorobenzene of the resin composition (C) used in this-application Example 5. FIG.

Hereinafter, the present invention will be described in detail for each item.
1. Laminate (1) Polyethylene resin composition (C)
The polyethylene resin composition (C) forming the polyethylene resin layer (I) used in the present invention is a polyethylene resin composition having the following properties (c-1).
(C-1) In the elution curve obtained by temperature-rise elution fractionation (TREF) with orthodichlorobenzene, the proportion of eluate of 80 ° C. or less is 28% by weight or more obtained by temperature-rise elution fractionation (TREF) with orthodichlorobenzene. The elution curve to be obtained can be obtained by the measuring means, measuring apparatus and measuring conditions described in detail in the following examples. For example, as shown in FIG. 1, from the integral elution curve with respect to the temperature of the obtained TREF, the percentage by weight of the component eluted at an elution temperature of 80 ° C. or less can be calculated.
According to the polyethylene-based resin composition satisfying the above (c-1), it becomes possible to develop adhesiveness with the polyethylene terephthalate resin layer (II) directly laminated thereon.
More preferably, in the elution curve obtained by the TREF, the polyethylene resin composition (C)
(C-1 ′) TREF 80 ° C. or lower eluate ratio is 28 wt% or more and 99.5 wt% or less,
More preferably,
(C-1 ″) TREF 80 ° C. or less eluate ratio is 50 wt% or more and 99.5 wt% or less,
More preferably
(C-1 ′ ″) TREF 80 ° C. or less The eluate ratio is 57% by weight or more and 99.5% by weight or less.
Furthermore, when the ratio of the eluate at TREF of 80 ° C. or less is 95.0% by weight or less, preferably 88.0% by weight or less, the laminate has excellent water vapor barrier properties.
In order to obtain a polyethylene-based resin composition (C) that satisfies this elution ratio, specifically, it is obtained by mixing a polyethylene-based resin (A) and a polyethylene-based resin (B), which will be described later, as described later. Is preferred.
Specifically, the polyethylene resin (A) having a lower density (and a high ratio of the eluate component of TREF 80 ° C. or less) and a higher density (a low ratio of the eluate component of a TREF 80 ° C. or lower component) By adjusting the kind and component ratio of each resin to be mixed when mixing the polyethylene resin (B), it has a TREF elution ratio in the above desired range, and preferably (c-2 The polyethylene resin composition (C) having the desired density range described in (1) can be obtained. Such a resin composition can satisfy the contradictory performance of improving the water vapor barrier property and improving the adhesiveness in a well-balanced manner. Although it is possible to use a single polyethylene-based resin as (C), there may be a problem in the balance of heat resistance, moisture resistance, and extrusion laminate processability as well as adhesiveness.

The polyethylene resin composition (C) used in the present invention preferably has the following properties (c-2) in order to exhibit extremely excellent adhesiveness and moldability.
(C-2) The test temperature is 23 ° C. and the density according to JIS-K7112 is 0.910 to 0.940 g / cm ³ .
(I) Density The density of the polyethylene resin composition (C) is measured according to a test temperature of 23 ° C. in accordance with JIS-K7112, and is 0.910 to 0.940 g / cm ³ , preferably 0.912 to 0. .937 g / cm ³ , more preferably in the range of 0.913 to 0.935 g / cm ³ . If the density is less than 0.910 g / cm ³ , the laminate molding resin does not slide well, and handling becomes worse. In addition, when used at high temperatures such as in a microwave oven or oven, the polyethylene resin layer may foam or cause poor appearance due to insufficient heat resistance of the polyethylene layer. A material having a density exceeding 0.940 g / cm ³ is not preferable because the adhesive strength with the polyethylene terephthalate resin is poor. It has been confirmed that when the density is 0.940 g / cm ³ or less, the adhesive strength is dramatically improved.

(Ii) MFR
The melt flow rate (MFR) of the polyethylene-based resin composition (C) is preferably 1.0 to 30 g / 10 min, more preferably 2 as measured by JIS K7210 (190 ° C., 21.18 N load). 0.025 g / 10 min, most preferably 3.0-20 g / 10 min. If the MFR (a) is less than 1.0 g / 10 min, there is a concern that the high-speed workability during extrusion laminating deteriorates. Moreover, what exceeds 30 g / 10min is unpreferable since there exists a possibility that the process stability at the time of an extrusion lamination process may deteriorate.

(Iii) Manufacturing method It is preferable to obtain a polyethylene-type resin composition (C) by mixing the polyethylene-type resin (A) and polyethylene-type resin (B) which are shown later, respectively. In the case of a single polyethylene resin, problems may occur in the balance of adhesiveness, heat resistance, moisture resistance, and extrusion lamination processability.
The blending ratio is preferably 10 to 95% by weight of the polyethylene resin (A) and 5 to 90% by weight of the polyethylene resin (B), more preferably 15 to 90% by weight of the resin (A) / resin (B ) 85 to 10% by weight, most preferably 20 to 85% by weight of resin (A) / 80 to 15% by weight of resin (B).
When the resin (A) is less than 10% by weight and exceeds 90% by weight of the resin (B), or when the resin (A) is more than 90% by weight and less than 10% by weight of the resin (B), a polyethylene resin Inconveniences such as inability to adjust various physical properties of the composition (C) are likely to occur, and as a result, the neck-in at the time of extrusion laminating is large, resulting in inconveniences such as poor stability at the time of processing.

In the polyethylene resin composition (C), an antioxidant, a heat stabilizer, a plasticizer, a tackifier, a metal may be added to the polyethylene resin composition (C) as necessary, as long as the characteristics of the polyethylene resin composition (C) are not impaired. Additives such as soaps, neutralizers, anti-blocking agents, lubricants, dispersants, pigments, dyes, etc., antifogging agents, antistatic agents, UV absorbers, light stabilizers, nucleating agents, etc. May be. The addition amount of the antioxidant is desirably small from the viewpoint of adhesiveness.
Moreover, you may mix | blend thermoplastic resins other than polyethylene in the range which does not impair the characteristic of the said polyethylene-type resin composition. Examples of the thermoplastic resin include other polyethylene resins, polyester resins, polyvinyl chloride resins, and polystyrene resins.

(2) Polyethylene resin (A)
The polyethylene resin (A) has (a-1) a test temperature of 23 ° C. and a density based on JIS-K7112 of 0.880 g / cm ³ or more and less than 0.930 g / cm ³ .

(I) Density The polyethylene resin (A) has a test temperature of 23 ° C. and a density according to JIS-K7112 of 0.880 g / cm ³ or more and less than 0.930 g / cm ³ , preferably 0.882 to 0.928 g / cm. ³ , more preferably in the range of 0.884 to 0.925 g / cm ³ , still more preferably 0.910 g / cm ³ or more. If the density is less than 0.880 g / cm ³ , the laminate molding resin does not slide well and handling is not preferable. Moreover, what a density exceeds 0.930 g / cm < ³ > will become difficult to manufacture industrially.

(Ii) MFR
The polyethylene resin (A) has an MFR measured in accordance with JIS K7210 (190 ° C., 21.18 N load) of 1.0 to 40 g / 10 min, preferably 2.0 to 35 g / 10 min, more preferably 3. The range is 0 to 30 g / 10 min, more preferably 20 g / 10 min or less. An MFR of less than 1.0 g / 10 min is not preferable because high-speed processability during extrusion laminating deteriorates. Moreover, since MFR exceeds 40 g / 10min, there exists a possibility that extrusion lamination processability may become unstable, and is unpreferable.

(Iii) Production method The polyethylene resin (A) in the present invention can be produced by various methods. From the viewpoints of adhesion of paper and polyethylene terephthalate and extrusion lamination processability, the following high-pressure radicals are used. It is preferable to use a high-pressure radical polymerization polyethylene obtained by a polymerization method or a mixture of the high-pressure radical polymerization polyethylene (A ′) and the ethylene α-olefin copolymer (A ″).

[Polymerization conditions]
The high-pressure radical polymerization method of the present invention is produced by bulk or solution polymerization under ultra-high pressure in the presence of a radical initiator such as oxygen or organic peroxide.
The polymerization temperature is 100 to 300 ° C, preferably 120 to 280 ° C, more preferably 150 to 250 ° C. If the polymerization temperature is less than 100 ° C, the yield may be lowered or a stable product may not be produced. If the polymerization temperature is more than 300 ° C, the reaction is not stabilized and it is difficult to obtain a polymer having a large molecular weight. The polymerization pressure is 50 to 400 MPa, preferably 70 to 350 MPa, more preferably 100 to 300 MPa. If the polymerization pressure is less than 50 MPa, a product having a sufficient molecular weight cannot be obtained, resulting in deterioration of workability and physical properties. When the pressure exceeds 400 MPa, stable production operation is difficult to perform.

[Polymerization operation]
In production, basically, ordinary high-pressure radical process low-density polyethylene production equipment and technology can be used. As the type of reactor, an autoclave type with a stirring blade or a tubular type can be used, and if necessary, a plurality of reactors can be connected in series or in parallel to perform multistage polymerization. . Furthermore, in the case of an autoclave type reactor, it is possible to provide temperature distribution or to perform more precise temperature control by dividing the inside of the reactor into a plurality of zones. By such an operation, it is possible to control a memory effect or the like.

Ethylene α-olefin copolymer (A ″) is produced by gas phase method, solution method, high pressure method, slurry method, etc., using general Ziegler catalyst, Phillips catalyst, metallocene catalyst, etc. Is done. An ethylene α-olefin copolymer produced by (co) polymerizing ethylene and α-olefin such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, The test temperature is 23 ° C., and the density according to JIS-K7112 is 0.880 to 0.930 g / cm ³ , preferably 0.882 to 0.930 g / cm ³ , according to JIS K7210 (190 ° C., 21.18 N load) ) Measured for MFR is preferably 1.0 to 40 g / 10 min, more preferably 2.0 to 35 g / 10 min, and most preferably 3.0 to 30 g / 10 min.
The mixing ratio of the high-pressure low-density polyethylene (A ′) constituting the polyethylene resin (A) and the ethylene α-olefin copolymer (A ″) can be arbitrarily defined, but preferably (A ′) is 5 The range (A ″) is 95 to 5% by weight with respect to ˜95% by weight, and more preferably the range (A ″) is 90 to 5% by weight with respect to 10 to 95% by weight. It is done. By constituting (A) with a mixture of (A ′) and (A ″), the adhesion to polyethylene terephthalate resin is further improved while maintaining the properties such as moisture resistance and extrusion laminating properties. Has an effect.

(3) Polyethylene resin (B)
The polyethylene resin (B) has (b-1) a test temperature of 23 ° C. and a density according to JIS-K7112 of 0.930 g / cm ³ or more and 0.970 g / cm ³ or less.

(I) Density The polyethylene-based resin (B) has a test temperature of 23 ° C. and a density according to JIS-K7112 of 0.930 to 0.970 g / cm ³ , preferably 0.932 to 0.970 g / cm ³ , More preferably, it is the range of 0.934-0.970 g / cm < ³ >. If the density is less than 0.930 g / cm ³ , moisture resistance and heat resistance are lowered, which is not preferable. Moreover, what a density exceeds 0.970 g / cm < ³ > becomes a thing which is difficult to manufacture industrially.

(Ii) MFR
The polyethylene resin (B) has an MFR (b) measured in accordance with JIS K7210 (190 ° C., 21.18 N load), preferably 1.0 to 40 g / 10 min, more preferably 2.0 to 35 g / 10 min. The most preferable range is 3.0 to 30 g / 10 min. The polyethylene resin (B) can be said to be a component for improving heat resistance, adhesiveness, and moisture resistance with respect to the low density polyethylene resin (A). When the MFR is less than 1.0 g / 10 min, the extrusion laminate is used. It is not preferable because high-speed processability during processing deteriorates. Moreover, since MFR (b) exceeds 40 g / 10min, there exists a possibility that extrusion lamination processability may become unstable, and is unpreferable.
(Iii) Production method Polyethylene resin (B) is produced by a process such as a gas phase method, a solution method, a high-pressure method, or a slurry method using a catalyst such as a general Ziegler catalyst, a Phillips catalyst, or a metallocene catalyst. Is done. It is produced by homopolymerization of ethylene or (co) polymerization of ethylene or ethylene and a small amount of propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene or other α-olefin.

(4) Laminate The laminate of the present invention is formed by forming a polyethylene resin layer (I) on one surface of a paper-based substrate and laminating a polyethylene terephthalate resin layer (II) thereon. Features. In particular, in the present invention, the polyethylene resin layer (I) is directly formed on one surface of a paper-based substrate, and the polyethylene terephthalate resin layer (II) is directly formed without providing an anchor coat layer thereon. It can be laminated.

(A) Substrate Examples of the substrate in the present invention include high-quality paper, craft paper, art paper, and cup base paper. In addition, a substrate mainly composed of paper can be coated with a substance that generates volatile gas by heating, or a substance that generates volatile gas by heating can be blended into the paper substrate. On a base material mainly made of paper, a picture, a character, a pattern, or the like can be printed with ink on paper such as pulp paper or synthetic paper. The paper used for the substrate preferably has a basis weight of 100 to 400 g / m ² , particularly 150 to 350 g / m ² .
In addition, the base material has been subjected to surface treatment and coating such as corona discharge treatment, flame treatment, plasma treatment, and ozone treatment in order to improve the wettability of the substrate surface and improve the adhesion to the polyethylene resin layer. May be.

(B) Polyethylene resin layer (I)
The polyethylene resin layer (I) according to the laminate of the present invention uses the above polyethylene resin composition (C). In order to obtain a laminate having good heat resistance, it is desirable that the melting point of the polyethylene-based composition (C) is selected in the range of 80 to 140 ° C, preferably in the range of about 90 to 135 ° C.

  The thickness of the polyethylene resin layer (I) is not particularly limited, but is 5 to 100 μm, and is preferably 10 to 100 μm in terms of moisture resistance, extrusion lamination processability, and adhesion to a substrate. When the thickness of the polyethylene resin layer (I) is less than 5 μm, pinholes are generated or it is difficult to perform stable film formation.

(C) Polyethylene terephthalate resin layer (II)
The resin constituting the polyethylene terephthalate resin layer (II) according to the laminate of the present invention may be a polyethylene terephthalate resin, but Homo-PET (homopolymer polyethylene terephthalate) or copolymerized PET (copolymer polyethylene terephthalate). ) Can be used.
The thickness of the polyethylene terephthalate resin layer (I) is not particularly limited, but is 10 to 100 μm, and is preferably 15 to 100 μm in terms of aroma retention, moisture resistance, and heat resistance.
In the present invention, particularly preferred is a laminate in which the polyethylene terephthalate resin layer (II) is directly formed on the polyethylene resin layer (I) by extrusion lamination. In the field of such laminates, it is usual to use a polyethylene terephthalate film previously formed into a film and try to laminate the polyethylene resin layer (I) via an adhesive layer agent. Thus, by directly forming the polyethylene terephthalate resin layer (II) on the polyethylene resin layer (I) without using an adhesive layer, the effect of improving the adhesiveness of the present invention can be further exhibited. .

About the laminated body of this invention, the layer which consists of various resin can be laminated | stacked also on the other surface of a base material. Examples of such layers include: (1) A thermoplastic resin layer such as polyethylene resin for imparting heat sealability is provided and used for paper containers, paper cups, trays, microwave oven containers and the like by known methods. It is possible. Alternatively, (2) it is possible to provide a foamed layer for imparting heat insulation to the laminate, mold it by a known method, and use it for paper containers, paper cups, trays, microwave oven containers, and the like.
As the thermoplastic resin layer or the foam layer, a known resin composition layer can be used. For example, as the resin composition layer forming the foam layer, polyethylene having a lower density than the resin layer (I) is used. Examples include resin layers made of high-pressure method low-density polyethylene, linear low-density polyethylene, linear low-density polyethylene having long-chain branches, and mixtures thereof, in accordance with JIS K7210 (190 ° C., 21.18 N load). The measured MFR is preferably in the range of 4 to 100 g / 10 min, the test temperature is 23 ° C., and the density based on JIS-K7112 is in the range of 0.890 to 0.935 kg / cm ³ .

In the laminate of the present invention, other layers may be provided in the interlayer, or its inner layer and / or outer layer, etc., as long as the effects of the present invention are not impaired. For example, the inner layer and / or outer layer of the laminate, Alternatively, one or more film layers, decorative layers, reinforcing layers, adhesive layers, barrier layers and the like may be provided between the layers.
Moreover, you may print etc. as needed. The printing may be performed partially or entirely with colored ink. Moreover, you may provide a foaming site | part partially or entirely using a foamable ink as needed. For the printing position, the size of the printing area, the printing method, the ink used, etc., a conventionally known technique can be appropriately selected and used.

Examples of the decorative layer include printed paper, film, nonwoven fabric, and woven fabric.
The reinforcing layer is not particularly limited, and examples thereof include polyolefin resins such as polyethylene and polypropylene, polyamide resins, and polyester resins.
Examples of the resin forming the adhesive layer include a copolymer of ethylene and an unsaturated carboxylic acid or a derivative thereof, a modified polyolefin resin obtained by grafting an unsaturated carboxylic acid on a polyolefin resin, an ethylene-vinyl acetate copolymer, etc. A hot melt, a normal adhesive, etc. are mentioned.
As the resin for forming the barrier layer, polyamide resin, polyester resin, ethylene-vinyl acetate copolymer saponified product (EVOH), polyvinylidene chloride resin, polycarbonate resin, stretched polypropylene (OPP), stretched polyester ( OPET), stretched polyamide, alumina vapor deposition film, inorganic oxide vapor deposition film such as silica vapor deposition film, metal vapor deposition film such as aluminum vapor deposition, and metal foil.

  As a method for producing the laminate of the present invention, as a method for laminating a polyethylene resin layer (I) and a polyethylene terephthalate resin layer (II) on a base material mainly composed of paper, an extrusion laminating process in which a molten resin is directly laminated is used. Examples of the method include a sand laminating method of laminating a film made in advance. In the present invention, it is particularly preferable to employ an extrusion laminating process.

Extrusion laminating is a molding method in which a molten resin film extruded from a T-die is continuously coated and pressure-bonded on a substrate, and coating and adhesion are performed simultaneously.
Sand laminating is a method in which a molten resin is poured between paper and a film to be laminated, and the molten resin acts as an adhesive to bond and laminate.

In the present invention, it is desirable to perform corona treatment on the surface of the paper base material when the polyethylene resin layer (I) is bonded to the paper base material in the extrusion laminate molding process.
Furthermore, it is desirable to perform corona treatment on the surface of the polyethylene resin layer (I) when the polyethylene terephthalate resin layer (II) is laminated on the polyethylene resin layer (I).
By performing corona treatment on the surface of the polyethylene resin layer (I), adhesion with the polyethylene terephthalate resin layer (II) is remarkably improved.
As a method for performing the corona treatment, a known method can be employed. Specifically, a paper substrate or a laminate of the paper substrate and the polyethylene resin layer (I) is passed between the insulated electrode and the dielectric roll, and the paper substrate surface or the polyethylene resin layer (I) surface side. From the above, it is possible to apply a high frequency high voltage to generate corona discharge.
The corona discharge amount is not particularly specified, but 10 to 80 W · min / m ² is exemplified. The corona discharge amount is expressed as follows.
Corona discharge amount = P / (L × V)
(Where, discharge power P (W), discharge electrode length L (m), passage speed V (m / min))

2. Use of Laminate Since the laminate of the present invention has gas barrier properties, scent retention, and moisture resistance, it is suitable for packaging of various articles, particularly food packaging containers that require gas barrier properties, scent retention, and moisture resistance. Moreover, since this laminated body has heat resistance, it is used as a tray, a cup, etc. As a use, a container for microwave ovens, a hot drink container, a cup soup container, a cup miso soup container, a cup noodle container, a natto container, a lunch box container, coffee Examples include cup containers and heat-resistant trays.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In addition, the testing method of the polyethylene-type resin used in a present Example, its physical property, the obtained laminated body, etc. is as follows.

1. Test method (1) MFR: Measured according to JIS K7210 (190 ° C., 21.18 N load).
(2) Density: The polyethylene resin (A) was measured under the following conditions.
The pellets were hot-pressed to prepare a press sheet having a thickness of 2 mm. The sheet was placed in a beaker having a capacity of 1000 ml, filled with distilled water, capped with a watch glass, and heated with a mantle heater. After boiling boiling water for 60 minutes, the beaker was placed on a wooden table and allowed to cool. At this time, the boiling distilled water after boiling for 60 minutes was adjusted to 500 ml so that the time until reaching room temperature was not less than 60 minutes. Moreover, the test sheet was immersed in the substantially center part in water so that it might not contact a beaker and the water surface. The sheet was annealed at a temperature of 23 ° C. and a humidity of 50% within a period of 16 hours or more and within 24 hours, then punched out to a length of 2 mm and measured at a test temperature of 23 ° C. according to JIS-K7112.
The polyethylene resin (B) was measured under the following conditions.
The pellets were pressed by a hot press to a thickness of 1 mm under the conditions of a temperature of 165 ° C. and a pressure of 10 Mpa, then cooled at a cooling rate of 25 ° C./min, and the sheet was taken out at 40 ° C. The sheet was annealed at a temperature of 23 ° C. and a humidity of 50% for 16 hours or more and within 24 hours, then punched and measured at a test temperature of 23 ° C. according to JIS-K7112.
(3) TREF: A sample is dissolved in orthodichlorobenzene (containing 0.5 mg / mL BHT) at 140 ° C. to obtain a solution. This was introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to 40 ° C. at a rate of 4 ° C./min, and then cooled at a rate of 1 ° C./min. To -15 ° C and hold for 20 minutes. Thereafter, orthodichlorobenzene (containing 0.5 mg / mL BHT) as a solvent is passed through the column at a flow rate of 1 mL / min, and the components dissolved in orthodichlorobenzene at −15 ° C. are eluted in the TREF column for 10 minutes. Next, the column is linearly heated to 140 ° C. at a temperature increase rate of 100 ° C./hour to obtain an elution curve.
The apparatus and measurement conditions described below were used.
(TREF part)
TREF column: 4.3 mmφ × 150 mm stainless steel column Column packing material: 100 μm surface inert treatment glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000
(Valve oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve, 4-way valve (sample injection part)
Injection method: Loop injection method Injection volume: Loop size 0.1ml
Inlet heating method: Aluminum heat block measurement temperature: 140 ° C
(Detection unit)
Detector: Fixed wavelength infrared detector MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: LC-IR micro flow cell, optical path length 1.5 mm, window shape 2φ × 4 mm oval, synthetic sapphire window measurement temperature: 140 ° C.
(Pump part)
Liquid feed pump: SSC-3461 pump manufactured by Senshu Scientific Co., Ltd. <Measurement conditions>
Solvent: Orthodichlorobenzene (with 0.5 mg / mL BHT)
Sample concentration: 5 mg / mL
Sample injection volume: 0.1 mL
Solvent flow rate: 1 mL / min

(4) Adhesive strength: The laminate was sampled with a width of 15 mm in the flow direction of the extrusion laminating process, and the interface between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) was 180 using Tensilon manufactured by Orientec Corporation. The adhesive strength was evaluated at an angle of ° and a speed of 300 mm / min.
(5) Water vapor permeability: In accordance with JIS K7129 A method, the water vapor permeability meter made by LYSSY was used and evaluated under the condition of 40 ° C.-90% RH in an area of 50 cm ² .

2. Resin (1) Polyethylene resin (A)
A1: MFR8.4g / 10 min, high-pressure low-density polyethylene having a density of ^{0.918g / cm 3 A2: MFR14g /} 10 min, polyethylene mixture density 0.919g / cm ³ (MFR8.4g / 10 min, density 0. a high-pressure 30 wt% low density polyethylene (A1) of 918g / cm ^3, MFR17g / 10 min, an ethylene-hexene copolymer produced at a density 0.918 g / cm ³ of the metallocene catalyst (A2 '') 70 weight % Mixture)
A3: MFR 11 g / 10 min, polyethylene mixture having a density of 0.913 g / cm ³ (MFR 8.4 g / 10 min, density 0.918 g / cm ³ of high-pressure low-density polyethylene (A1) 25% by weight, MFR 12 g / 10 min , A mixture of 75% by weight of ethylene / hexene copolymer (A3 ″) produced with a metallocene catalyst having a density of 0.911 g / cm ³ )
The A1 was polymerized in a high-pressure process low-density polyethylene production facility having an autoclave reactor. The above A2 ″ was polymerized by a high pressure process. The above A3 ″ was polymerized by a gas phase process.

(2) Polyethylene resin (B)
B1: Polyethylene resin with MFR 17 g / 10 min and density 0.966 g / cm ³ The raw material B1 was polymerized with ethylene alone in a slurry polymerization process using a Ziegler-based catalyst.
B2: MFR 11 g / 10 min, polyethylene resin having a density of 0.950 g / cm ³ The raw material B2 was obtained by copolymerizing ethylene and 1-butene in a gas phase process using a Ziegler catalyst.
B3: Polyethylene resin having an MFR of 5 g / 10 min and a density of 0.935 g / cm ³ The raw material B3 was obtained by copolymerizing ethylene and 1-butene by a gas phase process using a Ziegler catalyst.
(3) Polyethylene terephthalate resin: BK6180C manufactured by Mitsubishi Chemical Corporation

Example 1
As a resin used for the polyethylene resin layer (I), 100 parts by weight of a polyethylene resin (A1) was used alone.
Corona treatment (30 W · min / m ² ) is applied to one side of a kraft paper substrate having a basis weight of 75 g / m ² and is used for a polyethylene resin layer (I) using a 40 mmφ extruder and an extrusion laminator with a die effective width of 360 mm. As a resin, a polyethylene resin (A1) was extrusion laminated at a resin temperature of 320 ° C., a processing speed of 30 m / min, and a thickness of 30 μm to obtain a laminate of the polyethylene resin layer (I) and a paper substrate.
Next, the polyethylene terephthalate resin layer (II) is used as a material constituting the polyethylene terephthalate resin layer (II) on the surface of the polyethylene resin layer (I) of the laminate, and a 40 mmφ extruder and an extrusion laminator having a die effective width of 410 mm are used. Then, extrusion lamination was carried out at a resin temperature of 300 ° C., a processing speed of 15 m / min, and a thickness of 30 μm to obtain a laminate.
Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good. However, the water vapor barrier property was slightly lower.

(Example 2)
As a resin used for the polyethylene resin layer (I), a resin composition (C) obtained by melt blending 90 parts by weight of a polyethylene resin (A1) and 10 parts by weight of a polyethylene resin (B1) in advance using a 40 mmφ single screw extruder. A laminate was obtained in the same manner as in Example 1 except that it was used. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.

(Example 3)
Before the polyethylene terephthalate resin layer (II) was laminated by extrusion lamination on the surface of the polyethylene resin layer (I), corona treatment (30 W · min / m ² ) was performed on the surface of the polyethylene resin layer (I). Except for this, a laminate was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was very good. In Table 1, the notation “PET rupture” indicates that PET has a strength at which rupture occurs during the adhesive evaluation, and the adhesiveness is extremely good. However, the water vapor barrier property was slightly lower.

Example 4
As a resin used for the polyethylene resin layer (I), a resin composition (C) obtained by melt blending 90 parts by weight of a polyethylene resin (A1) and 10 parts by weight of a polyethylene resin (B1) in advance using a 40 mmφ single screw extruder. A laminate was obtained in the same manner as in Example 3 except that it was used. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was very good.

(Example 5)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 80 parts by weight of a polyethylene resin (A1) and 20 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. The integral elution curve obtained by temperature rising elution fractionation (TREF) of the resin composition (C) used in Example 5 with orthodichlorobenzene is shown in FIG.
Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was very good.

(Example 6)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 75 parts by weight of a polyethylene resin (A1) and 25 parts by weight of a polyethylene resin (B1) are previously melt-blended in a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.

(Example 7)
As a resin used for the polyethylene resin layer (I), 65 parts by weight of a polyethylene resin (A1) and 35 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder (C ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.

(Example 8)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 60 parts by weight of a polyethylene resin (A1) and 40 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 1 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.

Example 9
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 70 parts by weight of a polyethylene resin (A1) and 30 parts by weight of a polyethylene resin (B2) are previously melt-blended in a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.
(Example 10)
As a resin used for the polyethylene resin layer (I), 40 parts by weight of a polyethylene resin (A1) and 60 parts by weight of a polyethylene resin (B2) are melt-blended in advance using a 40 mmφ single screw extruder (C ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.
(Example 11)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 10 parts by weight of a polyethylene resin (A1) and 90 parts by weight of a polyethylene resin (B3) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was good.
(Example 12)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 75 parts by weight of a polyethylene resin (A2) and 25 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C). The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was very good.
(Example 13)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 65 parts by weight of a polyethylene resin (A3) and 35 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C). The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was very good.

(Example 14)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 50 parts by weight of a polyethylene resin (A1) and 50 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C). The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was confirmed to be slight.

(Example 15)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 40 parts by weight of a polyethylene resin (A1) and 60 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C). The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was confirmed to be slight.

(Comparative Example 1)
As a resin used for the polyethylene resin layer (I), a resin composition (C) in which 20 parts by weight of a polyethylene resin (A1) and 80 parts by weight of a polyethylene resin (B1) are melt-blended in advance using a 40 mmφ single screw extruder. ) Was used in the same manner as in Example 3 except that a laminate was obtained. Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C). The adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate was poor.

(Comparative Example 2)
A laminate is obtained in the same manner as in Example 1 except that the resin composition (C) using 100 parts by weight of the polyethylene resin (B2) alone is used as the resin used for the polyethylene resin layer (I). However, before measuring the adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate, it was impossible to process the polyethylene resin layer (I). Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).
(Comparative Example 3)
A laminate is obtained in the same manner as in Example 1 except that the resin composition (C) using 100 parts by weight of the polyethylene resin (B3) alone is used as the resin used for the polyethylene resin layer (I). However, before measuring the adhesion between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II) of the laminate, it was impossible to process the polyethylene resin layer (I). Table 2 shows the evaluation results of the obtained laminate and the physical properties of the used resin composition (C).

From the results of Examples 1 to 15 and Comparative Examples 1 to 3, the following matters were confirmed.
When the elution component amount of the resin composition (C) (c-1) TREF of 80 ° C. or lower is 28 wt% or more, the adhesiveness is expressed between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II). When the eluted component amount is less than 28 wt%, it can be seen that there is no adhesive strength between the polyethylene resin layer (I) and the polyethylene terephthalate resin layer (II).
Preferably, when the amount of the eluted component at TREF of 80 ° C. or less is 50 wt% or more and 57 wt% or more, the adhesion tends to be improved.
More preferably, in Examples 1 to 13 in which the density (c-2) of the resin composition (C) is 0.910 / cm ³ or more and 0.940 g / cm ³ or less, the density exceeds 0.940. Compared to Examples 14 and 15, it can be seen that the adhesiveness is dramatically improved.
Moreover, the direction in which the polyethylene terephthalate resin layer (II) is formed after the corona treatment on the surface of the polyethylene resin layer (I) tends to improve the adhesion.

Claims (12)

Forming a polyethylene resin layer (I) comprising the following polyethylene resin composition (C) on one surface of a paper-based substrate, and laminating a polyethylene terephthalate resin layer (II) on the polyethylene resin layer (I) A featured laminate.
(C) Polyethylene resin composition having the following property (c-1) (c-1) Elution curve obtained by temperature rising elution fractionation (TREF) with orthodichlorobenzene In the elution curve obtained at 80 ° C. or less Is 28% by weight or more The laminate according to claim 1, wherein the polyethylene-based resin composition (C) is a polyethylene-based resin composition further having the property (c-2).
(C-2) The test temperature is 23 ° C. and the density according to JIS-K7112 is 0.910 to 0.940 g / cm ^3.   The laminate according to claim 1 or 2, wherein the polyethylene terephthalate resin layer (II) is directly formed on the polyethylene resin layer (I) by extrusion lamination. The laminate according to any one of claims 1 to 3, wherein the polyethylene resin composition (C) comprises the following polyethylene resin (A) and polyethylene resin (B).
(A) Polyethylene resin having the following properties (a-1) (a-1) Test temperature 23 ° C., density in accordance with JIS-K7112 is 0.880 g / cm ³ or more and less than 0.930 g / cm ³ ( B) Polyethylene resin having the following properties (b-1) (b-1) Test temperature 23 ° C., density in accordance with JIS-K7112 is 0.930 g / cm ³ or more and 0.970 g / cm ³ or less The laminate according to any one of claims 1 to 4, wherein the polyethylene resin composition (C) is a polyethylene resin composition having the properties of (c-1 ').
(C-1 ′) TREF 80 ° C. or lower elution ratio is 28 wt% or more and 99.5 wt% or less The laminate according to any one of claims 1 to 5, wherein the polyethylene resin composition (C) is a polyethylene resin composition having a property of (c-1 '').
(C-1 ″) TREF 80 ° C. or lower eluate ratio is 50 wt% or more and 99.5 wt% or less The laminate according to any one of claims 1 to 6, wherein the polyethylene resin composition (C) is a polyethylene resin composition having the property of (c-1 ''').
(C-1 ′ ″) TREF 80 ° C. or less effluent ratio is 57 wt% or more and 99.5 wt% or less   The laminate according to claim 4, wherein the polyethylene resin (A) is high-pressure radical polymerization polyethylene.   The laminate according to claim 4, wherein the polyethylene resin (A) comprises a mixture of high-pressure radical polymerization polyethylene (A ') and an ethylene alpha olefin copolymer (A ").   The corona treatment is performed on the surface of the polyethylene resin layer (I) when the polyethylene terephthalate resin layer (II) is laminated on the polyethylene resin layer (I) in the molding process. The laminate according to any one of the above items.   The food packaging container obtained from the laminated body in any one of Claims 1-10.   The container for microwave ovens obtained from the laminated body of any one of Claims 1-10.

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