JPS6211787A - Gasket - Google Patents

Abstract

PURPOSE:A co-extruded and molded gasket having improved molding properties, deformation resistance of appearance, sealing and closing effects, comprising a rigid PVC resin, etc., a specific high-molecular weight substance and a plasticizer. CONSTITUTION:The aimed gasket consisting of (A) (i) a rigid PVC resin or ABS resin and (ii) 100pts.wt. high-molecular weight substance consisting of 30-80wt% vinyl chloride resin and 70-20wt% partially crosslinked acrylonitrile- butadiene copolymer and (B) 20-200pts.wt. plasticizer. Trimellitic ester, polyes ter, etc., may be cited as the preferable example of the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synthetic resin coextrusion molded gasket that has excellent moldability and resistance to deformation in appearance.

[Second, rice technology]

Conventionally, soft synthetic resins such as soft vinyl chloride resin or crosslinked rubber materials have been used for door stoppers or gaskets (hereinafter referred to as gaskets) for buildings, automobiles, kitchen appliances, etc.

When soft synthetic resin or rubber materials are used alone as extrusion molded or injection molded products, construction materials, automobiles,
Gaskets co-extruded or bonded with hard synthetic resin materials or metals may be used to facilitate connection to kitchen appliances.

[Problem that the invention seeks to solve]

However, it is difficult to melt and integrate hard synthetic resin and soft vinyl chloride resin in the same mold (hereinafter referred to as Gui).
(hereinafter referred to as coextrusion), the appropriate molding temperature difference between hard synthetic resin and soft vinyl chloride resin is usually 40-100°C.
If the die temperature is maintained at an appropriate temperature for hard synthetic resin, soft vinyl chloride =... The resin will thermally decompose and the product will not form, or the product will have an extremely poor appearance such as poor surface smoothness and waving. becomes. Conversely, if the appropriate die temperature is maintained for soft vinyl chloride resin, the soft vinyl chloride part will have a good appearance, but the hard synthetic resin will have poor molding or poor fusion due to insufficient molding temperature, and the appearance will be extremely poor. As a coextruded product, the product has extremely poor appearance and physical strength.

Furthermore, the resulting coextruded gasket product is highly deformed by pressure and compression during use (the sealing effect decreases during use, making it impossible to obtain a gasket product with good sealing performance).

On the other hand, when using cross-linked rubber materials as soft materials, products with excellent deformation resistance and good sealing performance can often be obtained, but due to the difference in molding temperature with the rubber material and the cross-linking treatment of the rubber part. Because the product requires heating, etc., coextrusion products with synthetic resins that use synthetic resins for hard parts are almost impossible to produce.

An object of the present invention is to solve these drawbacks and provide a coextruded gasket that has good appearance and deformation resistance, and has excellent sealing and sealing effects.

[Means for solving problems]

The present invention consists of hard vinyl chloride resin or ABS resin, 100 parts by weight of a polymer consisting of 30-80% by weight of vinyl chloride resin and 70-20% by weight of partially crosslinked acrylonitrile-butadiene copolymer, and 20-200 parts by weight of a plasticizer. This is a coextruded gasket made of a resin composition consisting of parts.

The vinyl chloride resin used here is not particularly limited as long as it is a vinyl chloride resin obtained by copolymerizing or graft polymerizing polyvinyl chloride and a small amount of vinyl acetate, ethylene-vinyl acetate resin, etc., but the average value measured according to JIS K-6721 is not particularly limited. When coextrusion molding is performed, it is desirable that the degree of polymerization is 2000 or more, as this meets the objective of the present invention, which is to reduce the molding temperature difference with the hard synthetic resin material and obtain a good gasket product.

The production method of the partially crosslinked acrylonitrile-butadiene copolymer used in the present invention is not limited as long as it contains a crosslinked acrylonitrile-butadiene copolymer that is insoluble in methyl ethyl ketone; A method of obtaining a copolymer with a polyfunctional monomer such as dimeter acrylate, or a method of increasing the reaction rate until a crosslinked acrylonitrile-butadiene copolymer insoluble in methyl ethyl ketone is produced, or
Any production method may be used, such as a method in which unvulcanized acrylonitrile-butadiene copolymer is crosslinked using a small amount of crosslinking agent. In general, partially crosslinked acrylonitrile-butadiene copolymers that are available include Chemi Gum P83 (product manufactured by Gutdeyer), JSRN201 (
Product manufactured by Japan Synthetic Rubber Co., Ltd.), Hycar 1422 (B
, F, products manufactured by Gutsrich), and the like.
- Further, the vinyl chloride resin and the partially crosslinked acrylonitrile-butadiene copolymer are contained in a weight ratio of 30-80% by weight/7.
It is desirable that the content be in the range of O-201t%. If the vinyl chloride resin content is less than 60% by weight, defects such as poor product appearance often occur during extrusion molding.
If the temperature is less than 1, the difference in proper molding temperature with the hard synthetic resin material during coextrusion molding becomes large, resulting in poor appearance of the product, which does not meet the purpose of the present invention.

The plasticizer used is generally a plasticizer used for vinyl chloride resin, etc., but preferably a so-called high molecular weight plasticizer such as trimellitic acid ester or polyester is used to improve moldability during coextrusion molding with hard materials. is good and suitable, but the amount used is 20-2 parts by weight per 100 parts by weight of resin.
If it is less than 20 parts by weight, it may cause poor moldability during extrusion molding or poor appearance of the gasket part, and if it exceeds 200 parts by weight, it should be at the appropriate extrusion temperature with the hard resin material. The difference becomes large, and problems such as poor appearance and insufficient strength of the gasket part occur.

Hard vinyl chloride resin used as a hard material is usually polyvinyl chloride with an average degree of polymerization of 500 to 1,500 or less than i.
! : (Not specified, but 10% or less) Extrusion containing appropriate amounts of necessary stabilizers, lubricants, processing aids, and/or ABS% MBS resin, etc. to vinyl chloride resin copolymerized or graft polymerized with vinyl acetate or ethylene vinyl acetate resin. Even moldable hard vinyl chloride can sufficiently achieve the purpose of the present invention. Furthermore AB
S resin is also a resin whose main three components are acrylonitrile-butadiene-styrene, which is generally used for molding as ABS resin, and although there are no particular restrictions on the individual components, the styrene component is α-methylstyrene, p - So-called heat-resistant ABS resin containing components with a high softening temperature such as methylstyrene is sufficiently used.

The co-extrusion device is not particularly specified, but usually the device (1) for kneading the soft resin material of the 1U6 hard synthetic resin kneading and extrusion device is joined and integrated with the same mold C.
The method for obtaining a coextruded product is determined, and the size of the individual extrusion equipment, single-screw, twin-screw, etc., model, vertical equipment, etc., is determined by the materials used, the shape of the coextruded product, They are appropriately selected depending on the dimensions.

The present invention will be explained below with reference to Examples.

〔Example〕

Examples 1 to 5 Materials having the resin composition shown in the table were stirred and mixed using a 751 Henschel mixer, and then mixed using a 90 ml single screw extruder (Ikegai Iron Works Co., Ltd.).
The mixture was kneaded and made into pellets using a commercial machine (manufactured by Kogyo Co., Ltd.) to obtain 15 kg of pellets each.

A coextrusion test was conducted using the following extruder.

Extruder: 65 m/m single screw extruder (manufactured by Ikegai Tekko Co., Ltd.) Extruder ■ 4 Q m/m vertical single screw extruder (manufactured by F Rustik Industrial Research Institute Co., Ltd.) Composition of hard resin material and soft material A die designed to

For Examples 1 to B, a hard vinyl chloride resin molding material (Denka Nikon R-2001 Denki Kagaku Kogyo Co., Ltd.) was used as the hard material, and coextrusion molding was performed at a die temperature of 190'C, and for Example 4S5. ABS resin Denka A
A coextrusion test was conducted using BS GTR-40: Denki Kagaku Kogyo (Company) at a die temperature of 200°C. The appearance of the soft portion (hereinafter referred to as gasket portion) of the obtained coextruded product was evaluated, and the height (H) of the gasket portion was measured. Furthermore, the obtained coextruded product was cut into a length of 10 cIrL and heated for 4 hours under a load of 6009 in a constant temperature bath kept at 60°C.

After taking it out and leaving it at room temperature for 2 hours, measure the height Hl of the gasket part and divide by the first measured height H) Comparative Examples 1 to 4 Materials with the resin compositions shown in the table were kneaded in the same manner as shown in the examples. After producing extruded pellets, coextrusion molding was performed using the same equipment and method as in the examples, and the products were evaluated and measured in the same manner.

Materials used (1) Vinyl chloride resin Electrified Vinyl 5H250 (degree of polymerization 2500) Denki Kagaku Kogyo Co., Ltd. (2) Partially crosslinked acrylonitrile-butadiene copolymer, TSRN201 Japan Synthetic Rubber Co., Ltd. (3) T
OTM Vinicide W-700 Dainippon Ink Co., Ltd. (4) Stabilizer Tripase (Kosei Co., Ltd.) (5) Lubricant Stearic acid Kao Sekiken Co., Ltd. (6) Hard vinyl chloride resin Denkabi Nicole R2001 Denki Kagaku Kogyo ( (7) ABS resin Denka ABS, GTR-40 [
Effects of the Invention] As shown in the Examples in the table, it was confirmed that the gasket of the present invention was excellent in moldability during manufacture, appearance, and heat deformation resistance.

Claims (1)

[Claims] 1. Hard vinyl chloride resin or ABS resin, 100 parts by weight of a polymer consisting of 30-80% by weight of vinyl chloride resin and 70-20% by weight of partially crosslinked acrylonitrile-butadiene copolymer, and 20-200 parts by weight of plasticizer. A coextruded gasket made of a resin composition.