JPH05212834A - Multi-layer plastic structure - Google Patents

Abstract

(57) [Abstract] [Purpose] In a multilayer plastic structure in which a polyester-based resin and a polyolefin-based resin have a multilayer structure with an intermediate adhesive layer interposed therebetween, the adhesive strength between the two layers is strong, and excellent performance as a multilayer plastic structure, To provide a molded product having an appearance. [Structure] A polyester-based resin layer, a polyolefin-based resin layer, and an intermediate layer having a mixture layer of a copolymer resin containing at least ethylene and a glycidyl group and a copolymer resin containing ethylene and α-olefin. , A multi-layer plastic structure comprising at least three layers of resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic structure having a multi-layer structure, more specifically, a multi-layer blow molding container, a multi-layer sheet or a multi-layer film formed of a polyester resin and a polyolefin resin. Can be used for containers such as bottles and tubes, packaging materials and the like.

[0002]

2. Description of the Related Art Polyolefin resins are widely used because of their excellent moldability and low price, and polyester resins are also widely used because of their excellent strength, gas barrier properties and gloss. Therefore, a combination of the two is also used to bring out more excellent characteristics. However, JP-A-51-9288
As shown in 0, modified polyethylene containing 0.1 to 10 mol% of unsaturated carboxylic acid or its derivative as a copolymerization component between polyester and polyolefin, or homopolymer of ethylene and vinyl acetate. ,
Alternatively, in the case of interposing a layer having a layer made of a mixture, the adhesive force between the two is at most 1.1 kg / cm, which cannot be said to be sufficient at present.

When such a multi-layered plastic structure having insufficient adhesive strength is used as a container, peeling between layers occurs after storage for a long period of time or during use of the container, which causes a problem in content protection performance. Or a problem such as unfavorable appearance may occur.

[0004]

The present invention has been made in order to solve the problems of the prior art as described above.
It is intended to provide a molded article having a strong adhesive strength between layers and having excellent performance and appearance as a multilayer plastic structure.

[0005]

A multilayer plastic structure of the present invention comprises a resin containing a copolymer resin having at least ethylene groups and glycidyl groups as an intermediate layer between a polyester resin layer and a polyolefin resin layer. It is characterized by using a mixture with a copolymer containing ethylene and α-olefin.

According to the embodiment of the present invention, the component having the glycidyl group is glycidyl methacrylate, and in the layer structure of the plastic structure, the plastic structure is provided between the intermediate layer and the polyolefin resin layer. One having a layer containing a recycled material, or one using the recycled material for the polyolefin resin layer itself, further, the multilayer plastic structure, the outer surface layer is a polyester resin, the inner layer is a polyolefin resin And a multi-layer blow molded product.

The multilayer plastic structure in the present invention may be a sheet-shaped product, a film-shaped product, or a molded product of these. Alternatively, a container may be obtained by stacking and extruding a parison having such a layer structure and performing hollow blow molding using compressed air.

The polyester resin is composed of a copolymer of polybasic acid and polyhydric alcohol. As such a polybasic acid, one containing terephthalic acid as a main component is preferable, and as a polyhydric alcohol, one containing ethylene glycol as a main component is preferable. The polybasic acid and the polyhydric alcohol may each include another polybasic acid and another polyhydric alcohol as a comonomer component.

Other polybasic acids that can be contained as a comonomer component in the polybasic acid include polybasic acids such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid and diphenyl ether dicarboxylic acid.

Other polyhydric alcohols that can be contained as a comonomer component in the polyhydric alcohol include trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, diethylene glycol, 1,
A polyhydric alcohol component such as 1-cyclohexanedimethylol can be used.

Usual polyethylene resin, polypropylene resin and the like can be used for the polyolefin resin layer.

As the adhesive resin used as the intermediate layer, a mixture of a copolymer resin containing at least ethylene and a glycidyl group and a copolymer resin containing ethylene and α-olefin can be used. As the copolymer resin containing ethylene and α-olefin, an ethylene / butene copolymer resin or the like can be used. The glycidyl group content in the glycidyl group-containing copolymer resin is 8 to 20 mol.
% Is preferable, when the glycidyl group is too small, the adhesive force to the polyester resin is insufficient, and when it is too large,
Lack of stability as a thermoplastic resin.

[0013]

The multi-layer plastic structure of the present invention has a polyester resin layer and a polyolefin resin layer as an intermediate layer.
By using a mixture of a copolymer resin containing at least ethylene and a glycidyl group and a copolymer resin containing ethylene and α-olefin, a strong adhesive force between the polyester resin and the polyolefin resin can be obtained.

As the adhesion mechanism of the intermediate layer to the polyester resin layer, in the glycidyl group-containing copolymer resin, it is considered that the epoxy component in the glycidyl group reacts with the polyester terminal group to show the adhesion mechanism. It is considered that the copolymer resin containing α-olefin and α-olefin has a melt-adhesive mechanism to obtain an adhesive force with the polyester resin.

Further, a glycidyl group-containing copolymer resin,
Mixtures of ethylene and α-olefin copolymer resins are believed to exhibit synergistic adhesion of reactive and tacky adhesion.

[0016]

【Example】

<Example 1> Using a multi-layer blow molding machine having three screw extruders, screw A is an amorphous polyester resin, and screw B is an intermediate layer having a glycidyl methacrylate / ethylene copolymer (ethylene 88
%) And ethylene / butene copolymer (density 0.9
The 50:50 weight ratio blend of 0) was supplied to screw C with a high-density polyethylene resin, and the mixture was plasticized and extruded under the following conditions to form a laminated parison through a simultaneous confluent type head. It was sandwiched between blow molds having a cylindrical bottle-shaped cavity, the upper part of the parison was cut, and blow molding was performed using compressed air. The obtained bottle had a glossy appearance and had no problem in physical properties.

[0017]

Example 2 Using a multi-layer blow molding machine having four screw extruders, an amorphous polyester resin for screw A and an intermediate layer of glycidyl methacrylate / ethylene copolymer for screw B ( Ethylene 88 mol%) and ethylene / butene copolymer 5
To the screw C, which was dry-blended at a weight ratio of 0:50, was supplied a resin obtained by mixing high-density polyethylene and recycled scrap material of the laminated plastic according to the present example at a weight ratio of 50:50, and to the screw D. A high-density polyethylene resin is supplied, plasticized and extruded under the following temperature conditions, a laminated parison is formed through a simultaneous confluent type head, and the polyester resin layer /
4 of middle layer / recycled material containing layer / high density polyethylene resin layer
A parison having a layer structure was extruded. The parison was sandwiched in a blow molding die having a flat bottle-shaped cavity, the upper part of the parison was cut, and then blow molding was performed using compressed air.

[0019]

The obtained bottle has a polyester resin layer /
The adhesive strength of the intermediate layer was 3.90 kg / 15 mm width, and the adhesive strength of the intermediate layer / recycled material mixed layer was so strong that it could not be peeled off, and the bottle had no physical problems.

Example 3 Using the blow molding machine used in Example 1, screw C has a high-density polyethylene resin, and screw B has a glycidyl methacrylate / ethylene copolymer and ethylene / butene copolymer resin as an intermediate layer. 40:60 weight ratio mixture of
The polyethylene terephthalate resin is dehumidified and dried and then supplied to form a parison in which a high density polyethylene layer / intermediate layer / polyethylene terephthalate resin layer are laminated in this order from the parison outer surface layer through a sequential confluent type multilayer head, The parison is sandwiched between blow molds having a cylindrical bottle-shaped cavity, and after cutting the upper part of the parison,
Blow molding was performed using compressed air. The obtained bottle had a polyethylene terephthalate resin layer on the inner surface layer of the bottle and was excellent in content resistance.

Screw diameter Barrel temperature Screw A 30 mmφ 270 ° C. Screw B 25 mmφ 200 ° C. Screw C 50 mmφ 190 ° C.

Example 4 A multi-layer sheet extruder having three screw extruders was used. The screw E was for the polyester resin used in Example 1 and the screw F was for the intermediate layer used in Example 1. Example 1 for resin and screw G
The high-density polyethylene resin used in 1. was supplied and plasticized and extruded under the following conditions, the layers were joined in a manifold, and a sheet having a thickness of 2 mm was extruded. The sheet was cut into a predetermined size, reheated, and vacuum-pressure formed in a vacuum-pressure die having a cup-shaped concave die to obtain a cup-shaped molded product having an inner diameter of 70 mm and a height of 50 mm.

The cup has an inner surface layer made of a polyester resin layer, the surface layer made of a high-density polyethylene layer, and the polyester layer and the intermediate layer have an adhesive strength of 3.8 kg / 15.
The width of mm, the intermediate layer and the polyethylene layer had a strong peeling strength such that they could not be peeled off, and there was no problem in physical properties.

Screw diameter Barrel temperature Screw E 60 mmφ 200 ° C. Screw F 55 mmφ 200 ° C. Screw G 60 mmφ 190 ° C.

Comparative Example 1 A multilayer blow-molded container obtained by the same method as in Example 1 except that an ethylene / vinyl acetate copolymer was used as the intermediate layer.

[0027]

[Table 1]

Table 1 shows the adhesion between the polyester / interlayer of the containers obtained in each example.

[0029]

EFFECTS OF THE INVENTION According to the method of the present invention, a laminated plastic structure made of a combination of a polyester resin and a polyolefin resin can be used to obtain an article having a strong adhesive force, which causes a problem such as peeling when formed into a molded article such as a container. A molded product that does not occur can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shunichi Kato 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (5)

[Claims] 1. A polyester-based resin layer, a polyolefin-based resin layer and an intermediate layer, a copolymer resin containing at least ethylene and a glycidyl group, and ethylene and α.
A multi-layer plastic structure consisting of a resin composition of at least three layers, characterized in that a mixture of copolymer resins containing olefins is used. 2. The multilayer plastic structure according to claim 1, wherein the component having a glycidyl group is glycidyl methacrylate. 3. The layer structure according to claim 1, wherein the layer structure includes a layer containing a recycled material of the multilayer plastic structure between the intermediate layer and the polyolefin resin layer. The multilayer plastic structure according to claim 2. 4. The structure according to claim 1, wherein the polyolefin resin layer in the above constitution is a mixture of at least three layers, wherein the polyolefin resin is a mixture of a polyolefin resin and a recycled material for the multilayer plastic structure. The described multilayer plastic structure. 5. A multilayer blow molded product according to claim 1, wherein the multilayer plastic structure is a multilayer blow-molded product in which the outer surface layer is a polyester resin and the inner layer is a polyolefin resin. Plastic structure.