JPS6333438A - Thermoplastic rubber composition - Google Patents

Abstract

PURPOSE:To provide the titled composition containing a specific carboxyl- containing chloroprene rubber, a carboxyl-containing vinyl chloride resin, a univalent or bivalent metal compound and a plasticizer usable without vulcanization and having excellent high-temperature creep resistance and weather resistance. CONSTITUTION:The object composition can be produced by mixing (A) a carboxyl-containing chloroprene rubber containing >=10(wt%), preferably 30-98% gel component insoluble in toluene (preferably having a carboxyl group content of 0.2-10%), (B) a carboxyl-containing vinyl chloride resin (preferably having a carboxyl group content of 0.2-10%), (C) a univalent or bivalent metal compound (e.g. magnesium acetylacetonate) and (D) a plasticizer (e.g. di-2-ethylhexyl phthalate). Preferably, the ratio of A/B is 1:9-8:2, the amount of the component D is 20-300pts.(wt.) per 100pts. of the component B and that of the component C is 0.1-3mol-equivalent based on the total amount of the carboxyl group of the components A and B.

Description

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

(Prior art) Chlorogren rubber has properties such as oil resistance, weather resistance, heat resistance, and flame retardancy, and is widely used in automobile parts and other applications due to these properties, but it naturally cannot be vulcanized. is the premise.

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 excellent moldability, low cost, weather resistance, colorability, etc., and is widely used. However, since it is inferior to vulcanized rubber in terms of creep properties at high temperatures, its use at high temperatures is limited. Therefore, attempts have been made to improve the creep properties by using vinyl chloride resins with a high degree of polymerization or those containing gel content. Furthermore, a method is known in which compression set is improved by adding a crosslinked rubber substance to vinyl chloride resin containing these glue components. (Japanese Patent Application Laid-Open No. 58-215442.

59-51933) However, these methods also provide 1
High-temperature creep properties at temperatures above 00°C (load, compression set 1
It is difficult to improve the rebound resilience.

Therefore, there is currently a strong demand for a thermoplastic rubber that can be thermoplastically processed and has high-temperature creep properties similar to vulcanized rubber without vulcanization.

(Problems to be Solved by the Invention) In view of the above situation, the present inventors have conducted extensive research to solve the above problems, and have found that chloroprene rubber having a glue content and carboxyl group, a carboxyl group-containing vinyl chloride resin, and a monovalent Or, by using a composition containing a divalent metal compound and a plasticizer as essential components, thermoplastic processing is possible and high temperature creep properties are significantly improved without vulcanization, The present invention has now been completed.

(Means for Solving the Problems) Thus, according to the present invention, the amount of dal that is insoluble in toluene is reduced to 1
There is provided a thermoplastic rubber composition comprising a carboxyl group-containing chloroprene rubber having 0% by weight or more, a carboxyl group-containing vinyl chloride resin, a monovalent or divalent metal compound, and a plasticizer.

The carboxyl group-containing chloroprene rubber used in the present invention includes chloroprene and α.

β-unsaturated Cal? copolymers with phosphoric acid monomers, hydrolyzed copolymers of chloroglene and α,β-unsaturated carenoic acid ester polymers, or addition reactions of chloroglene polymers with carboxylic acids, etc. Can be mentioned. Note that this chloroprene rubber may be one obtained by copolymerizing a small amount of other copolymerizable monomers. α in the above,
Examples of the β-unsaturated carboxylic monomer include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid, dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid, and monomethyl malate,
Examples include monoesters of dicarboxylic acids such as monoethyl maleate, moptil maleate, monomethyl itaconate, monoethyl itaconate, and monobutyl itaconate.

In order to make this chloroprene rubber contain a glue component, monomers having multiple double bonds in the molecule, such as divinylbenzene, diallyl 7-thale, -/allyl maleate, and trimethylolpropane triacrylate, are added. A method such as polymerization or generation of intermolecular crosslinks through a post-treatment reaction using a mother oxide or the like may be employed as appropriate.

Further, the carboxyl group content is 0.05 to 20% by weight, preferably 0.2 to 10% by weight. If it is less than 0.05% by weight, the impact resilience at high temperatures is not necessarily sufficient, and if it is contained in an amount exceeding 20% by weight, it is often pointless or undesirable due to other properties.

The dull content that is insoluble in toluene refers to the amount of chloroprene rubber added to 100 grams of toluene. After dissolving 3 ink at room temperature overnight,
This refers to the residue that is filtered through mesh wire mesh.

The gel content is required to be 10% by weight or more, preferably 30% by weight or more. If the dullness content is less than 10% by weight, compression set, which is one of the main characteristics of high-temperature creep properties, will not be sufficiently improved, which is not preferable. Note that the upper limit of the dullness is not particularly limited, but in consideration of workability, it is preferably 98% or less.

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,
Copolymerization of radicals such as monobutyl maleate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, etc. with monoesters of phosphoric acid, (2)
(3) Copolymerization of vinyl chloride and α, β-, β-carboxylic acid esters followed by water decomposition, and (3) Cal? Examples include those obtained by addition reaction of a phosphoric acid-containing compound. The carboxyl group content in this resin is usually 0.05 to 20% by weight, preferably 0.2%.
~10% by weight. If it is less than 0.05% by weight, the impact resilience at high temperatures will not be sufficiently improved, and if it is contained in an amount exceeding 20% by weight, it is often pointless or undesirable due to other properties. Note that the average degree of polymerization of the vinyl chloride resin is not particularly limited, but it is usually 500 to s, ooo, and a vinyl chloride resin containing a glue component insoluble in tetrahydrofuran may be used.

As the monovalent or divalent metal compound, Ll.

Na # K m Ca # Mg” * Ca
-@Ba # Zn j+ + Metal oxides such as Cd''+, hydroxides, acetates, propionates, octylates, casilyates, stearates, carboxylates such as naphthenates, thiocarboxylate Examples include acid salts, sulfonates, phosphates, and complex salts of the above metals with acetylacetone, etc.These may be used alone or in combination of two or more.The amount of the metal compound to be added is as follows:
0 for the total carboxyl group content of carboxyl group-containing chloroprene rubber and carboxyl group-containing vinyl chloride resin.
．． 1 to 3 molar equivalents are preferred. It is presumed that this metal compound reacts ionically with the carboxyl group in the chloroprene rubber and vinyl chloride resin, and acts as a so-called ionic crosslinking agent that crosslinks the chloroprene rubber and vinyl chloride resin.

As the plasticizer, plasticizers commonly used for soft vinyl chloride resins can be used, such as di-2-ethylhexyl phthalate, di-n-octyl 7-talate, diisodecyl 7-thaleate, digtyl 7-talate, and digtyl 7-thale. 7-talic acid esters such as tallate; dioctyl adipate,
Linear dibasic acid esters such as dioctyl sebacate: Trimellitic acid esters, polyester polymer plasticizers: Epoxy plasticizers such as epoxidized soybean oil and epoxidized linseed oil:) Liphenyl phosphate, tri Phosphate ester plasticizers such as cresyl phosphate may be used alone or in combination of two or more.

The mixing ratio of carboxyl group-containing chloroglene rubber and carboxyl group-containing vinyl chloride resin is 0.5:9.5 to 9:
1, preferably l:9 to 8:2. If the mixing ratio is smaller than 0.5:9.5, a sufficient compression set improvement effect will not be exhibited, and if it exceeds 9:1, the melt fluidity will decrease and processing methods will be 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.
00 parts by weight, preferably 20 to 300 M parts.

When producing the thermoplastic rubber composition in the present invention,
As in general vinyl chloride resin, stabilizers, lubricants,
Mild additives such as fillers, antioxidants, ultraviolet absorbers, processing aids, blowing agents, pigments, flame retardants, and impact resistance aids can be added as necessary. Further, other polymers may be mixed.

(Effect of the invention) By molding the obtained composition using ordinary vinyl chloride resin processing methods such as extrusion molding, compression molding, calendar molding, blow molding, and injection molding, molding with excellent high-temperature creep properties and weather resistance can be achieved. Goods can be obtained.

This molded product can be used in automobile window seal materials, electric wire sheath materials, and other materials that require the same characteristics. It can be suitably used for fish and the like.

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

Example 1 Chloroprene rubber, vinyl chloride resin, magnesium acetylacetonate, 100 parts of di-2-ethylhexyl 7-talate, and 4 parts of digtyltin malate shown in Table 1 were mixed into 1
The mixture was kneaded for 10 minutes using heated rolls at 60°C to obtain a sheet. These sheets were heated and pressed at 175° C. for 10 minutes to produce pressed test pieces of a predetermined thickness.

The impact resilience of this press test piece was expressed as impact resilience modulus (%) measured at 140°C using a Dunlop trigsometer according to BS 903 Part A8:1963. The compression set was expressed as the compression set rate (%) after 70 hours at 100°C at 25% compression, as measured in accordance with JIS K-6301. Further, weather resistance was evaluated by observing the discoloration state of the test piece after 500 hours using a sunshine type sederometer. The results are shown in Table 1.

Umbrella 1 When polymerizing chloroglene, the carboxyl group content was adjusted by the amount of acrylic acid added, and the amount of toluene-insoluble glue was adjusted by the amount of divinylbenzene added.

*2 Acrylonitrile dibutadiene weight ratio 33:6
Copolymer Book 3 of No. 7 When vinyl chloride was polymerized, the carboxyl group content was adjusted by adding monomethyl malate.

40: No discoloration to slight discoloration ×: Discoloration to brown Example 2 Carboxyl base i 1.2%, toluene insoluble dull content 85
% chloroprene rubber 100 parts, carboxyl group content 1
．． 8%, vinyl chloride polymer 10 with an average degree of polymerization of 2.500
The same experiments and evaluations as in Example 1 were conducted, except that 4 m (0 parts, diptyltin male) and the metal compound and plasticizer in the amounts shown in Table 2 were added.

The results are shown in Table 2.

Claims (1)

[Claims] A thermoplastic rubber composition comprising a carboxyl-containing chloroprene rubber having a toluene-insoluble gel content of 10% by weight or more, a carboxyl group-containing vinyl chloride resin, a monovalent or divalent metal compound, and a plasticizer. .