JPH09314763A - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminate with a good low temperature extension durability by providing an ethylene vinyl alcohol compolymer as a gas barrier. SOLUTION: In order to form this laminate, a joint material layer having a tensile elastic modulus of 7×10<9> -3×10<10> dine/cm<2> (-40 deg.C) and a thermoplastic elastomer of a tensile elastic modulus of 3×10<9> -7×10<9> dine/cm<2> (-40 deg.C) are laminated in turn on both the surfaces of a gas barrier layer consisting of a tensile elastic modulus 3×10<10> -7×10<10> dine/cm<2> (-40 deg.C). Furthermore, a butyl rubber and nitrile rubber can be vulcanization adhered on the thermoplastic elastomer layer of the laminate.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a laminate.
More specifically, it relates to a laminate having excellent gas barrier properties and low temperature extension durability.

[0002]

2. Description of the Related Art Diaphragms, bladders and the like are used in accumulators and the like for transmitting the pressure of fluid such as gas, and are required to have the property of deforming according to the pressure of fluid without allowing the fluid to permeate. Therefore, it is required not only to have gas barrier properties against hydrogen gas, oxygen gas, nitrogen gas, etc., but also to have excellent low temperature extension durability depending on the application.

In order to achieve both the gas barrier property and the low temperature elongation durability, it is necessary to use them at their respective compromise points. When the gas barrier property is emphasized, the low temperature elongation durability is greatly deteriorated. Selection of resin is required. For example, when a well-known ethylene-vinyl alcohol copolymer (saponified ethylene-vinyl acetate copolymer) is used as a gas barrier resin, the elastic modulus is high,
Since cracks and damages occur during extension operation, although there are examples where a plasticizer was added to reduce the elastic modulus, it is generally difficult to balance gas barrier properties and low temperature extension durability at a high level. Has been done.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laminate having an ethylene-vinyl alcohol copolymer as a gas barrier layer, which has excellent low temperature elongation durability.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Tensile modulus of elasticity of 3 × 10 ^{10 to} 7 × 10 ¹⁰ dynes / cm ² (-40 ℃) made of ethylene-vinyl alcohol copolymer on both sides, tensile modulus of elasticity of 7 × 10 ^{9 to} 3 × 10 ¹⁰ dynes / Cm ² (-40
Is achieved by bonding the material layers and tensile elastic modulus 3 × 10 ⁹ ~7 × 10 ⁹ dynes / cm ² thermoplastic elastomer layer sequentially stacked laminate (-40 ° C.) in ° C.). Butyl rubber or nitrile rubber can be further vulcanized and adhered onto the thermoplastic elastomer layer of this laminate.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene-vinyl alcohol copolymer used in the gas barrier layer has the property that when the copolymerization ratio of ethylene is high, both the gas barrier property and the tensile elastic modulus are high. At 40 mol% or more, film equivalent 10cc / 10μ / m ² / 24hr ・ atm (70
It is possible to satisfy the gas barrier property of (° C) or less,
The tensile modulus (-40 ° C) is also 3 × 10 ¹⁰ dynes / cm ² or more.
Such a tensile elastic modulus is specified in relation to the gas barrier property, provided that the value is 7 × 10 ¹⁰ dynes / cm ²
If it becomes above, it will not be able to endure deformation. The gas barrier layer made of such a copolymer is generally formed to a thickness of about 20 to 200 μm, preferably about 50 to 100 μm.

A bonding material layer for bonding a thermoplastic elastomer layer as a flexible layer is generally provided on both surfaces of the gas barrier layer in a thickness of about 10 to 200 μm, preferably about 20 to 100 μm. As such a bonding material, a maleic anhydride modified polypropylene or the like is used, and this material layer not only has a bonding effect between the gas barrier layer and the flexible layer, but also holds a tensile elastic modulus between these two. Also, the low temperature extension durability is improved.

As the thermoplastic elastomer, an olefinic thermoplastic elastomer is preferably used. As the olefinic thermoplastic elastomer, ethylene-
Blends of propylene rubber and polypropylene, blends of high-viscosity ethylene-propylene rubber and polypropylene, blends of crystalline ethylene-propylene copolymer and polyethylene, etc., having a tensile modulus of 3 × 10 Those having a size of ^{9 to} 7 × 10 ⁹ dynes / cm ² are used.
In addition to the olefin-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer or the like is also used, and on these thermoplastic elastomer layers, butyl rubber or nitrile rubber having a lower elastic modulus is preferably vulcanized and adhered.
A layer having such a tensile elastic modulus is selected and used as a lower layer therefor, and if a layer having a tensile elastic modulus higher than that is used, the low temperature elongation durability is lowered. Such a thermoplastic elastomer layer is generally formed with a thickness of about 100 to 1000 μm, preferably about 300 to 500 μm.

When butyl rubber or nitrile rubber is vulcanized and bonded as the outermost layer, a rubber compound having a good bondability with the thermoplastic elastomer, for example, the following rubber compound is used. (Butyl rubber compound) Butyl rubber (Nippon synthetic rubber product Butyl 365) 100 parts by weight Zinc oxide 10 〃 Stearic acid 1 〃 FEF carbon black 60 〃 Sulfur 2 〃 Vulcanization accelerator 2 〃 (Nitrile rubber compound) Nitrile rubber (Nippon Synthetic rubber) Rubber product JSR240S) 100 parts by weight Zinc oxide 5 〃 Stearic acid 1 〃 HAF carbon black 65 〃 Dioctyl sebacate 20 〃 Anti-aging agent (RD) 2 〃 〃 (810NA) 3 〃 〃 (NBC) 2 〃 Vulcanization accelerator ( CZ) 2 〃 〃 (TT) 2 〃 sulfur 0.5 〃

The gas barrier layer, the bonding material layer, and the thermoplastic elastomer layer can be laminated by a method of laminating and laminating the monolayer films of these layers. However, since each of these layer components is thermoplastic. Preference is given to coextrusion. When further vulcanizing and adhering butyl rubber or nitrile rubber onto these laminates, an unvulcanized sheet of these rubber compounds is bonded onto the laminate, and then vulcanization and adhesion under heat and pressure conditions. Is done.

[0011]

EFFECT OF THE INVENTION A bonding material layer and a thermoplastic elastomer layer having a small tensile elastic modulus are successively laminated on a resin layer having a very high tensile elastic modulus and therefore a high gas barrier property, and preferably a butyl rubber or a nitrile rubber is further used. By laminating materials having a low elastic modulus, it is possible to obtain a laminate having a large bonding force between the layers and having good low temperature extension durability. The laminate having such good properties is effectively used as a diaphragm, a bladder, or the like.

[0012]

Next, the present invention will be described by way of examples.

Example 1 A laminate having the following layers was produced by a coextrusion method. Ethylene-vinyl alcohol copolymer layer 100 μm (Kuraray product Eval, tensile modulus 5 × 10 ¹⁰ dynes / cm ² ) Maleic anhydride modified polypropylene layer 50 μm (Mitsui Petrochemicals Admer, tensile modulus 2 × 10 ¹⁰ dynes / cm ² ) Olefinic thermoplastic elastomer layer 300 μm (AES JAPAN product Santoprene, tensile modulus 5 × 10 ⁹ dynes / cm ² )

Example 2 On the olefinic thermoplastic elastomer layer of the laminate obtained in Example 1, a vulcanized adhesive layer of the above butyl rubber compound was formed.
(Thickness 600 μm, tensile modulus 3 × 10 ⁹ dynes / cm ² ) was further formed.

Example 3 On the olefinic thermoplastic elastomer layer of the laminate obtained in Example 1, a vulcanized adhesive layer of the above-mentioned nitrile rubber compound was applied.
(Thickness 600 μm, tensile modulus 3.5 × 10 ⁹ dynes / cm ² ) was further formed.

Example 4 In Example 1, instead of the olefin thermoplastic elastomer, the same layer of polyamide thermoplastic elastomer (Dainippon Ink Products Grelax A250, tensile modulus 7 × 10 ⁹ dynes / cm ² ) is the same. It was formed with a thickness (300 μm).

Example 5 A vulcanized adhesive layer of the above-mentioned butyl rubber compound was formed on the polyamide thermoplastic elastomer layer of the laminate obtained in Example 4.
(Thickness 600 μm, tensile modulus 3 × 10 ⁹ dynes / cm ² ) was further formed.

COMPARATIVE EXAMPLE 1 In Example 4, another polyamide-based thermoplastic elastomer (Dainippon Ink Products Grelax A100, tensile modulus 2
× 10 ¹⁰ dynes / cm ² ) is used and the layers have the same thickness (300
μm).

Comparative Example 2 In Example 5, another polyamide-based thermoplastic elastomer (Greak A100, tensile elastic modulus 2 × 10 ¹⁰ dynes / cm
² ) was used and the layers were formed with the same thickness (300 μm).

With respect to the laminates obtained in each of the above Examples and Comparative Examples, the following items were measured. Elongation durability test under -40 ℃ condition: A measurement sample punched out in a dumbbell shape is extended by 50% under -40 ℃ environment condition (5Hz)
Repeat the measurement and measure the number of times until it breaks. Gas barrier property after product durability test: -4 product diaphragm
After operating up and down 100 times between the highest point and the lowest point at a speed of 0.01 Hz under an environmental condition of 0 ° C, the gas permeation coefficient for N ₂ gas (unit: cc · 10 μ / m ² · 24 hr · atm) measured at 70 ° C

The results obtained are shown in the following table. Example: Extension durability test under -40 ° C condition (times) Gas barrier property after product durability test Example 1> 1000 7 〃 2> 1000 〃 〃 3> 1000 〃 〃 4 800 〃 〃 5 800 〃 Comparative example 1 <500 > 20 〃 2 <500 〃

Claims (2)

[Claims] 1. Tensile modulus 3 × 10 ^{10 to} 7 × 10 ¹⁰ dynes / cm
² (-40 ℃) ethylene-vinyl alcohol copolymer on both sides of the gas barrier layer, tensile elastic modulus 7 × 10 ⁹ ~ 3 × 10 ¹⁰
Dyne / cm ² (-40 ℃) bonding material layer and tensile modulus 3 × 1
A laminate formed by sequentially laminating thermoplastic elastomer layers of 0 ^{9 to} 7 × 10 ⁹ dynes / cm ² (-40 ° C.). 2. The laminate according to claim 1, further comprising butyl rubber or nitrile rubber vulcanized and adhered onto the thermoplastic elastomer layer.