JPH0222053A - Deep drawing laminate - Google Patents

Abstract

PURPOSE:To obtain a deep drawing laminate of good quality by laminating a gas barrier layer composed of an ethylene/vinyl alcohol copolymer, an outer layer resin layer, a seal layer composed of a polyolefinic resin and a polyamide resin layer through adhesive resin layers. CONSTITUTION:As a gas barrier layer 4, an ethylene/vinyl alcohol copolymer or vinylidene chloride resin layer and, around this layer, an outer layer resin composed of a soft vinyl chloride resin, a seal layer 5 composed of a polyolefinic resin and a polyamide resin layer 3 composed of a polycondensate of terephthalic acid/hexamethylenediamine and nylon are laminated by adhesive resin layers 2 composed of low density polyethylene. The laminate thus obtained is highly excellent in oxygen blocking properties and can be subjected to boiling treatment and is excellent in flexibility, oil resistance, pinhole resistance and low temp. deep drawing properties.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is highly oxygen barrier, can be boiled, is flexible, has oil resistance, pinhole resistance, and can be deep drawn at low temperatures. This invention relates to a laminate with excellent properties.

[Conventional technology]

In general, research into laminating so-called synthetic resin molded products, especially films, etc., has been conducted for a long time. The aim is to utilize the strengths of each and compensate for the weaknesses of each. Specifically, improvements include heat resistance, water vapor and gas permeability, resistance to oil and chemicals, impact resistance, mechanical strength, stiffness, heat sealability, and economic efficiency. Particularly in food packaging, food products may react with oxygen and the like and deteriorate in quality, so packaging materials that have gas barrier properties have often been used. Vinylidene chloride resins and ethylene-vinyl alcohol copolymers have been known as resins with excellent gas barrier properties, and have been used to take advantage of their respective characteristics.

Conventionally, the vacuum packaging of processed meat, etc. has been carried out using the
A laminate of ethylene resin and gas barrier layer resin as seen in Publication No. 4 has been used, but with the diversification and increase in content, the laminate is now used by deep drawing. Due to this, the strength of the laminate was insufficient and many pinholes were generated.

In order to improve these points, a laminate incorporating a polyamide resin layer as seen in JP-A-59-212261 was devised and used, but compared to ethylene resin, polyamide resin has less flexibility. -, the laminate becomes stiff and has poor fit to the contents.
Furthermore, since it has a high melting point and is hard at low temperatures, it is difficult to form at low temperatures and is particularly unsuitable for deep drawing.

[Problem to be solved by the invention]

The present invention was developed as a result of research to improve the above-mentioned problems. By blending a non-quality polyamide resin with a conventional polyamide resin, it becomes a resin layer that is flexible and elastic, and furthermore, The present invention was completed based on the finding that drawing formability is extremely improved.

The purpose is to have a high degree of gas barrier property, boiling processability, flexibility, and excellent pinhole resistance.
An object of the present invention is to provide a laminate having good deep drawability at low temperatures.

[Failure to solve the problem]

The present invention uses an ethylene-vinyl alcohol copolymer or vinylidene chloride resin layer (A) as a gas barrier layer, an outer resin layer (B), a polyolefin resin layer (C
), the polyamide resin layer (D) is the adhesive resin layer (E)
This is a laminate characterized in that it is laminated with the following materials.

The ethylene-vinyl alcohol copolymer used in the present invention is a saponified ethylene-vinyl acetate copolymer, and preferably has an ethylene content of 32 to 47 mol%. Vinylidene chloride resin is a binary or multi-component copolymer of 60 to 97 parts by weight of vinylidene chloride and unsaturated monomers such as vinyl chloride, alkyl acrylate, acrylic acid, acrylonitrile, etc. Plasticizers, stabilizers, etc. can be added.

The outer layer resin has a molecular weight of 1000 to 100 as a plasticizer.
Soft vinyl chloride resin using 00 oligomer, olefin elastomer, polyester elastomer,
Polyamide elastomer, low crystalline polybutadiene, etc. can be used.

As the polyolefin resin used as the sealing material, low density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymer, ethylene-acrylic acid copolymer, ethylene-alkyl acrylate copolymer, ionomer resin, etc. are used. be able to.

The polyamide resin layer is made of one or two of 6-nylon, 6-6.6 nylon, and 6-12 nylon produced by a polycondensation reaction of ω-aminocarboxylic acid or a polycondensation reaction of tribasic acid and diamine. Polyamide resin of more than 30 to 9 species
5% by weight of terephthalic acid or isophthalic acid, or both of these and hexamethylene diamine copolymerized polyamide resin mixed polyamide resin with 5 to 70% by weight of non-grade nylon blended to reduce crystallinity. Use.

The adhesive resin layer is made of resins such as low density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymer, ethylene-propylene copolymer, high density polyethylene, polypropylene, acrylic acid, -methacrylic acid, etc. Monobasic unsaturated fatty acids or dibasic unsaturated fatty acids such as maleic acid, fumaric acid, ichconic acid, etc., or those obtained by chemically bonding dibasic unsaturated fatty acids such as anhydrides, etc. Either of these and ethylene-vinyl acetate copolymer similarly acid-modified 10-50%
and weight blends, as well as blends of these with 10 to 20% by weight of copolymer polyester elastomer, ethylene-maleic anhydride copolymer, and ethylene-methyl methacrylate-glycidyl acrylate ternary copolymer. .

For manufacturing the laminate of the present invention, any known method such as coextrusion or lamination can be used, but coextrusion is particularly preferred because of its simple manufacturing process.

〔Example〕

Six-layer laminates of Examples and Comparative Examples having the thickness structure and layer structure shown in Table 1 were made by extruding each resin using six extruders and guided to a coextrusion multilayer die, and evaluation thereof. The results are also shown in Table 1.

Various evaluation tests were conducted using the following methods.

+al Pinhole resistance test The outer surface (surface) and inner surface (sealing surface) of the film were evaluated in the following two ways.

(i) Static method A sinusoidal needle with a tip of 0.3flR is applied vertically to the surface of the film set horizontally with a jig, and a load is applied to the top of the needle until no pinhole is formed for more than 1 minute. The load was measured.

(11) Set the film and needle in the same way as the shock method and static method, and place the needle on top of the needle.
When a 0g steel ball is dropped, the highest falling height without pinhole formation was measured.

(bl Deep drawing test corner is R30, bottom corner is R40, additional drawing is 80mm, 120mm We investigated the lowest value of .

(C) Boiling Resistance Test Boiling was performed in a hot water bath at 98°C for 15 to 30 minutes, and the degree of whitening was visually evaluated.

◎: Transparency does not change at all ○: Slightly whitens but becomes transparent over time △: Slightly whitens and cloudy feeling remains even after time passes ×: Whitens and does not return to its original state.

*5-PVC Polymerization degree 1800, plasticizer (molecular weight 2000) 50 parts by weight
Made by Atmer-146-12 nylon made by Ube Industries Al Made by UBE Nylon 6-6.6 Nylon Made by Ube Industries Made by UBE Nylon Made by Mitsubishi Chemical Made by NOVAM ID
Ehal It is a laminated material that can be processed into molded products with a good appearance, and has extremely low pinhole formation during low-temperature transportation, which has been a problem in the past, and has excellent deep drawability at low temperatures. body can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is an example of a cross-sectional view of the laminate of the present invention. Patent Applicant: Sumitomo Bakelite Co., Ltd. No. 1 3 to 1 Noah Midonodo, Riha Tsuki et al.

Claims (2)

[Claims] (1) Ethylene-vinyl alcohol copolymer or vinylidene chloride resin layer (A) as a gas barrier layer, outer resin layer (B), polyolefin resin layer (C) as a sealing layer.
), a laminate for deep drawing forming, characterized in that a polyamide resin layer (D) is laminated together with an adhesive resin layer (E). (2) The polyamide resin layer contains 5 to 70% by weight of a polycondensate of terephthalic acid or isophthalic acid, or both of these and hexamethylene diamine, and one type of nylon 6, 6-6,6 nylon, or 6-12 nylon. The laminate for deep drawing according to claim 1, which is a mixture of 30 to 95% by weight of two or more types of polyamide resins.