JPS6330552A - Thermoplastic elastomer composition - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thermoplastic elastomer composition, and more particularly, to a thermoplastic elastomer composition that does not require vulcanization and has excellent high-temperature creep properties and weather resistance. .

(Conventional technology).

Acrylate elastomers have excellent heat resistance and weather resistance, and are widely used in automatic mold parts and other applications due to these properties, but in order to achieve these properties, they must be vulcanized.

On the other hand, vinyl chloride resin containing a plasticizer, known as soft vinyl chloride resin, has a flexible, rubber-like feel.
Compared to vulcanized rubber, it has superior moldability, cost, weather resistance, colorability, etc., and is widely used. However, its creep properties at high temperatures are inferior to that of vulcanized rubber, so its use at high temperatures is limited. Therefore, the creep properties are improved by using vinyl chloride resins with a high degree of polymerization or those containing gel content. Attempts have been made to improve the compression set by adding cross-linked nitrile rubber to vinyl chloride resin containing gel content (Japanese Patent Application Laid-Open No. 58-215442゜59). -'5193
3). However, even with these methods, it is difficult to simultaneously improve high-temperature creep properties (particularly compression set and impact resilience) at 100° C. or higher and weather resistance.

Therefore, there is a strong demand for thermoplastic elastomers that can be thermoplastically processed and have high-temperature creep properties close to those of vulcanized rubber even without vulcanization.

(Problems to be Solved by the Invention) In view of this situation, the present inventors have attempted to solve the above-mentioned problems (as a result of intensive research, they have found that an acrylate entomer containing a specific amount of gel content, a carboxyl group-containing vinyl chloride resin, etc.) , by using a composition containing a monovalent or divalent metal compound and a plasticizer as essential components, thermoplastic processing is possible and high-temperature creep properties are significantly improved without vulcanization. According to the present invention, an acrylate elastomer having a gel content insoluble in methyl ethyl ketone of 10% or more by weight, and a carboxyl group. Provided is a thermoplastic elastomer composition comprising a vinyl chloride resin, a monovalent or divalent metal compound, and a plasticizer.

The acrylate elastomer used in the present invention is an acrylate homopolymer elastomer, an ethylene-
Examples include acrylate copolymer elastomer, ethylene-vinyl acetate-acrylate copolymer elastomer, acrylate-acrylonitrile copolymer elastomer, azirylate-vinyl acetate-acrylonitrile copolymer elastomer, acrylate-butadiene-acrylonitrile copolymer elastomer, etc. However, it is not particularly limited to these elastomers.

In order to contain gel content in this acrylate elastomer, divinylbenzene, diallyl phthalate, diallyl maleate, trimethylolpropane tri(meth)
Adopt appropriate methods such as copolymerizing monomers with multiple double bonds in the molecule, such as acrylate and triallyl trimellitate, or generating intermolecular crosslinks through post-treatment reactions using peroxide, etc. do it.

The gel content insoluble in methyl ethyl ketone refers to the addition of acrylate elastomer cL25', which was masticated with a water-cooled roll for 10 minutes, to 100 d of methyl ethyl ketone.
This refers to the residue obtained by filtration through an 8° wire mesh after dissolving at room temperature for 4 hours. The content of gel molecules i1o is required to be at least 50% by weight, preferably at least 50% by weight. If the gel content is less than 10% by weight, compression set, which is one of the characteristics of high-temperature creep properties, will not be sufficiently improved, which is not preferable.

In addition, as the carboxyl group-containing vinyl chloride resin, (1
) Vinyl chloride, monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid, or dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid, and monomethyl maleate, monoethyl maleate,
Copolymerized with dicarboxylic acid monoesters such as motuptil maleate, monomethyl itaconate, monoethyl itaconate, and motuptil itaconate, (2)
Examples include those obtained by polymerizing vinyl chloride and all α,β-unsaturated carboxylic acid esters and then hydrolyzing them, and (3) those obtained by adding a carboxylic acid-containing compound after producing a normal vinyl chloride polymer. It will be done. The carphokyfur group content in this resin is usually 0.05 to 20% by weight, preferably CL2
~10 weight factor ◎0.05 weight arrogance and high temperature impact resilience at high temperatures is not sufficiently improved, and it is not only meaningless to contain more than 20 weight yen, but is often undesirable due to other characteristics. . Note that the average degree of polymerization of the vinyl chloride resin is not particularly limited, but is usually 500 to 5,000.

As a monovalent or divalent metal compound, L1+.

Na, K,, Cs, Mg, Ca
, Ba, Zn.

Metal oxides such as CD++, hydroxides, acetates, propionates, octylates, caprates, stearates, carboxylates such as naphthenates, thiocarboxylate, sulfonate, phosphoric acid Examples include salts and complex salts of the metals and acetylacetone. These may be used alone or in combination of two or more. The amount of metal compound added is
It is preferably 0.1 molar equivalent to 3 molar equivalent relative to the carboxyl group weight of the vinyl chloride resin. It is presumed that this metal compound acts as a so-called ionic crosslinking agent that ionically reacts with the carboxyl group in the vinyl chloride resin and crosslinks the vinyl chloride resin.

As plasticizers, plasticizers commonly used for soft vinyl chloride resins can be used, including phthalic acids such as di-2-ethylhexyl phthalate, di-octyl phthalate, diisodecyl phthalate, dibutyl phthalate, and dibutyl phthalate. Ester; dioctyl adipate,
Linear dibasic acid esters such as dioctyl sebacate: trimellitic acid esters, polyester polymer plasticizers; epoxies such as epoxidized soybean oil and epoxidized linseed oil, L
[agent; )! j Phosphate ester plasticizers such as phenyl phosphate and tricresyl phosphate can be used alone or in combination of two or more.

The mixing ratio of the acrylate elastomer and the carboxyl group-containing vinyl chloride resin is in the range of 0.5:9.5 to 9:1, preferably 1:9 to 8:2.

If the mixing ratio is smaller than 0.5:9.5, sufficient compression set improvement effect will not be achieved. If it exceeds 1, the melt fluidity of the bath decreases and processing methods are restricted, which is not preferable.

The amount of plasticizer used in the present invention is appropriately selected depending on the hardness of the target product, but in order to obtain a soft rubber-like product, it is necessary to use 20 to 300 parts by weight of plasticizer per 100 parts by weight of carboxyl group-containing vinyl chloride resin. part is preferred.

In producing the thermoplastic nitrogenous composition of the present invention, stabilizers, lubricants, fillers, antioxidants, ultraviolet absorbers, processing aids, blowing agents, pigments, flame retardants, Various additives such as impact resistance aids can be added as necessary. In addition, other polymers may be mixed.O (Effect of the invention) The obtained composition may be molded by ordinary vinyl chloride resin processing methods such as extrusion molding, compression molding, calendar molding, blow molding, injection molding, etc. As a result, a molded product with excellent high temperature creep properties and weather resistance can be obtained.

This molded product can be suitably used for automobile window seal materials, electric wire sheath materials, packing materials, etc., which require the same characteristics.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and parts in the examples are based on weight unless otherwise specified.

Example 1 Acrylate elastomer, vinyl chloride resin, magnesium acetylacetonate and G2-
100 parts of ethylhexyl phthalate and 4 parts of diptyltin malate were kneaded for 10 minutes using hot rolls at 160°C to obtain a sheet. These sheets were heated and pressed at 175° C. for 1Q minutes to prepare pressed test pieces with a predetermined thickness.

The impact resilience of this press test piece was measured using a Dunlop tripunmeter.BS・903PartA8: 1'? 6
The impact elasticity modulus (expressed as a penalty) was measured at 140° C. according to No. 3. The compression set was expressed as the compression set rate after 100'CX70 hours at 25% compression measured according to JISK-6501. Further, weather resistance was evaluated by observing the discoloration of the test piece after 500 hours using a sunshine type therometer. The results are shown in Table 1.

Example 2

Claims (1)

[Claims] A thermoplastic elastomer composition comprising an acrylate elastomer having a gel content insoluble in methyl ethyl ketone of 10% by weight or more, a carboxyl group-containing vinyl chloride resin, a monovalent or divalent metal compound, and a plasticizer.