JP3370481B2 - Chloroprene polymer composition and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chloroprene polymer composition having excellent ozone resistance and tear strength, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Chloroprene-based polymers have a good balance of physical properties such as general rubber physical properties, weather resistance, heat resistance, and chemical resistance, so they are used in a wide range of fields such as general industrial rubber products, automobile parts, and adhesives. Has been done. However, in recent years, the environment in which rubber products are used has become harsh, and it is becoming difficult for conventional chloroprene-based polymers to cope with it.

Although ozone resistance is one of the required properties, a method of adding an antioxidant is generally used in chloroprene polymers and is widely used.

[0004]

However, the method of adding an antioxidant may cause problems such as burning of an unvulcanized product, bloom of the antioxidant, and reduction in tensile strength of the vulcanized product. Therefore, not only is it difficult to select the type and amount of the antiaging agent, but also the effect of improving ozone resistance is not sufficient.

The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a chloroprene polymer composition having a significantly improved ozone resistance and excellent tear strength, and a method for producing the same. Is.

[0006]

That is, the present invention provides a polymer latex of chloroprene having an average particle size of 100 n.
TECHNICAL FIELD The present invention relates to a chloroprene polymer composition obtained by mixing a polymer emulsion of an α, β-unsaturated carboxylic acid ester of m or less, and a method for producing the same. Specifically, the above α, β-unsaturated carboxylic acid ester is an acrylic acid ester, and further, the α, β-unsaturated carboxylic acid ester is n-butyl acrylate. The method consists of mixing a polymer latex of chloroprene with a polymer emulsion of an α, β-unsaturated carboxylic acid ester having an average particle size of 100 nm or less.

The chloroprene polymer used in the present invention is 2
It is a homopolymer of -chloro-1,3-butadiene (hereinafter referred to as "chloroprene") or a copolymer obtained by polymerizing chloroprene and one or more monomers copolymerizable with chloroprene.

Examples of the monomer copolymerizable with chloroprene in the present invention include 2,3-dichloro-1,3-
Examples thereof include butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, sulfur, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and if necessary, two or more kinds may be used. I don't care.

Polymerization of chloroprene alone or a monomer mixture containing chloroprene and a monomer copolymerizable therewith in the present invention can be carried out by any known method, but radical polymerization is carried out in an aqueous emulsion. The method is the most common.

The emulsifier used in the aqueous emulsion polymerization is not particularly limited and may be any emulsifier generally used in the emulsion polymerization of chloroprene, for example, rosin acid salt, fatty acid salt and alkylbenzene sulfonate. And the like, nonionic emulsifiers such as alkyl polyethylene glycol and polyvinyl alcohol, and cationic emulsifiers such as quaternary ammonium salts. However, anionic emulsifiers such as rosin acid salts and fatty acid salts are preferable.

The polymerization temperature in the present invention is not particularly limited, but it is preferably in the range of 0 to 55 ° C. At temperatures lower than 0 ° C, the solidification of water becomes a problem, and at temperatures higher than 55 ° C, the vapor pressure of chloroprene is increased. Therefore, pressurization equipment is needed.

The molecular weight of the chloroprene polymer can be controlled by
It can be performed using a chain transfer agent. The chain transfer agent is not particularly limited, and commonly known chain transfer agents, for example, alkyl mercaptans such as dodecyl mercaptan, xanthogen disulfides such as diethylxanthogen disulfide, halogenated hydrocarbons such as iodoform can be used. .

The polymerization initiator may be an organic or inorganic peroxide used in a usual chloroprene emulsion polymerization method, and examples thereof include benzoyl peroxide, potassium persulfate and ammonium persulfate. Further, a redox type radical initiator may be used for the purpose of controlling the reaction and completely carrying out the polymerization.

The polymer emulsion of α, β-unsaturated carboxylic acid ester in the present invention is obtained by emulsion polymerization of α, β-unsaturated carboxylic acid ester, and the average particle diameter of the emulsion is 100 nm or less. By mixing the polymer emulsion with the chloroprene latex, the tear strength of the resulting chloroprene polymer composition is increased.

Here, the α, β-unsaturated carboxylic acid ester is an ester composed of an α, β-unsaturated carboxylic acid and an alcohol. Examples of the α, β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid,
Examples thereof include maleic acid and fumaric acid, with acrylic acid being particularly preferred.

Examples of alcohols include alkyl alcohols such as ethyl alcohol, butyl alcohol, dodecyl alcohol and octadecyl alcohol, alkenyl alcohols such as allyl alcohol, cyclic alcohols such as cyclopentyl alcohol and cyclohexyl alcohol, benzyl alcohol and phenethyl alcohol. Examples thereof include aralkyl alcohols such as methoxyethyl alcohol, ethoxyethyl alcohol, glycidyl alcohol, and dialkylaminoethyl alcohol. Among them, n-butyl alcohol and ethyl alcohol are preferable, and n-butyl alcohol is particularly preferable.

The α, β-unsaturated carboxylic acid ester polymer of the present invention is obtained by copolymerizing a monomer other than the α, β-unsaturated carboxylic acid ester within a range that does not impair the effects of the present invention. Is also good. Monomers other than α, β-unsaturated carboxylic acid esters include acrylic acid, methacrylic acid, acrylonitrile, ethylene, propylene, styrene, vinyl acetate, vinyl chloride, isoprene, butadiene, chloroprene, and 2,3-dichloro-1. , 3-butadiene, glycidyl methacrylate, allyl glycidyl ether, 2-
Examples include chloroethyl vinyl ether and vinyl chloroacetate.

The emulsifier for emulsion polymerization of the α, β-unsaturated carboxylic acid ester is not particularly limited, and various emulsifiers can be used as in the polymerization of chloroprene. As a method of controlling the particle size of the polymer emulsion of the α, β-unsaturated carboxylic acid ester of the present invention to 100 nm or less, for example, there is a method of adjusting the monomer / water ratio and the amount of the emulsifier used, It is not limited to this.

The number average molecular weight of the polymer of the α, β-unsaturated carboxylic acid ester is preferably 300,000 or more. However, it is not necessarily limited to this. The molecular weight may be adjusted using a chain transfer agent, and as the chain transfer agent, a generally known chain transfer agent, for example, alkyl mercaptans such as dodecyl mercaptan, xanthogen sulfides such as diethylxanthogen sulfide, and iodoform. And the like can be used.

Further, the polymerization temperature of the α, β-unsaturated carboxylic acid ester is not particularly limited, but it is preferably selected in the range of 0 to 90 ° C. At 0 ° C or below, the solidification of water is 9
Above 0 ° C, water evaporation becomes a problem.

The chloroprene polymer composition of the present invention is
The average particle size of the emulsion is α, β-
Mixed polymer emulsion of unsaturated carboxylic acid ester
It is essential to obtain it. The content of the polymer of α, β-unsaturated carboxylic acid ester is not particularly limited,
The range of 3 to 60% by weight is preferable and 5 to 40% by weight in order to obtain a composition excellent in ozone resistance and tear strength without deteriorating various physical properties originally possessed by the chloroprene polymer.
Is more preferable, and 5 to 30% by weight is further preferable.

[0022]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. In the following description, parts and% are based on weight.

Of the chloroprene polymer latex (A1)
Manufacture 3 liters of glass Kolben, under a nitrogen stream, water 10
0 parts, 5 parts of disproportionated rosin acid as an emulsifier, 1.0 part of potassium hydroxide, and 0.8 parts of sodium salt of a formaldehyde naphthalene sulfonic acid condensate as a dispersant were charged, and after dissolution, 100 parts of chloroprene and with stirring. A mixture with 0.1 part of n-dodecyl mercaptan was added. Polymerization was carried out at a polymerization temperature of 40 ° C using potassium persulfate as a polymerization initiator, and when the conversion rate of the monomer reached 65%, tertiary butyl catechol and thiodiphenylamine were added to terminate the polymerization, and unreacted. The monomers were removed under reduced pressure to obtain a chloroprene polymer latex (A1).

Of the chloroprene polymer latex (A2)
Chloroprene polymer latex (A2) was prepared in the same manner as in chloroprene polymer latex (A1) except that 95 parts of chloroprene and 5 parts of 2,3-dichloro-1,3-butadiene were used instead of 100 parts of chloroprene produced. Got

It is composed of an α, β-unsaturated carboxylic acid ester.
Preparation of polymer (B1)
0 parts, 7.5 parts of sodium dodecylbenzene sulfonate as an emulsifier were charged and dissolved, and then 100 parts of n-butyl acrylate as an α, β-unsaturated carboxylic acid ester,
0.01 part of n-dodecyl mercaptan was added with stirring. Polymerization was carried out at a polymerization temperature of 70 ° C. using potassium persulfate as an initiator until the monomer conversion reached 98%.
-Butyl acrylate polymer emulsion (B1) was obtained.

It consists of α, β-unsaturated carboxylic acid ester
Preparation of polymer (B2)
0 parts and 5 parts of sodium dodecylbenzenesulfonate as an emulsifier were charged and dissolved, and then 100 parts of n-butyl acrylate as an α, β-unsaturated carboxylic acid ester, and n-
0.01 part of dodecyl mercaptan was added with stirring. Polymerization was carried out at a polymerization temperature of 70 ° C. using potassium persulfate as an initiator until the monomer conversion reached 98%, and n−
A butyl acrylate polymer emulsion (B2) was obtained.

It is composed of an α, β-unsaturated carboxylic acid ester.
Production of polymer (B3) according to
0 part and 2 parts of sodium dodecylbenzenesulfonate as an emulsifier were charged and dissolved, and then 100 parts of n-butyl acrylate as an α, β-unsaturated carboxylic acid ester and n-
0.01 part of dodecyl mercaptan was added with stirring. Polymerization was carried out at a polymerization temperature of 70 ° C. using potassium persulfate as a radical initiator until the monomer conversion reached 98%, and an n-butyl acrylate polymer emulsion (B
3) was obtained.

It is composed of an α, β-unsaturated carboxylic acid ester.
Measurement of average particle size of polymer emulsion using a Coulter submicron (model N4 COULTER ELECTRONICS INC.) For polymer emulsions (B1) to (B3) consisting of α, β-unsaturated carboxylic acid ester The average particle size of was measured, and the results are shown in Table 1.

Example 1 The chloroprene polymer latex (A1) obtained above and α,
β-unsaturated carboxylic acid ester polymer emulsion (B
1) was added to 100 parts of (A1) while stirring 10 parts of (B1) (as solid content), and the mixture was further stirred sufficiently to obtain a chloroprene-based polymer composition by freeze-drying.

Example 2 Using (A2) as the chloroprene polymer latex, the chloroprene polymer composition was obtained in the same manner as in Example 1.

Comparative Example 1 A chloroprene polymer composition was obtained in the same manner as in Example 1, except that (B2) was used as the α, β-unsaturated carboxylic acid ester polymer emulsion.

Comparative Example 2 A chloroprene polymer composition was obtained in the same manner as in Example 1 except that (B3) was used as the α, β-unsaturated carboxylic acid ester polymer emulsion.

Comparative Example 3 A chloroprene polymer composition was obtained in the same manner as in Example 1 except that the chloroprene polymer latex (A1) was used alone.

The above chloroprene polymer composition (raw rubber) was vulcanized according to the formulation shown in Table 2 and a physical property test was conducted. JIS-K for hardness, tensile strength, elongation and tear strength
The test was performed according to 6301. Moreover, the ozone resistance was based on JIS-K6259, and the dynamic ozone test (tensile method) was performed. The test results are shown in Table 3.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

As can be seen from Table 3, the chloroprene polymer composition of the present invention is excellent in ozone resistance and tear strength, and also has excellent mechanical properties originally possessed by the chloroprene polymer. Is held. Therefore, it is suitable as a material for rubber boots, specifically, constant velocity joint boots, rack and pinion boots, ball joint boots, etc., particularly in the field of automobile industry. Further, it is also suitable as a rubber hose, specifically a brake hose, a power steering hose, a fuel hose, a radiator hose, an automobile hose such as a car air conditioner hose, and an external rubber material for various high pressure hoses. Further, the chloroprene-based polymer composition of the present invention, a building gasket,
Specifically, air tight, spacer, glazing gasket, joint gasket, zipper gasket,
It is also suitable as a material for setting blocks, expansions, etc., and also suitable for anti-vibration rubber and belts.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-56-84777 (JP, A) JP-A-62-96576 (JP, A) JP-A-60-36543 (JP, A) JP-A-61- 118440 (JP, A) JP 64-69647 (JP, A) JP 62-90376 (JP, A) JP 60-112841 (JP, A) JP 8-226539 (JP, A) JP 59-93701 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 11/00 C08L 33/04

Claims (4)

(57) [Claims] 1. A chloroprene-based polymer composition obtained by mixing a polymer latex of chloroprene with a polymer emulsion of an α, β-unsaturated carboxylic acid ester having an average particle diameter of 100 nm or less. 2. The chloroprene polymer composition according to claim 1, wherein the α, β-unsaturated carboxylic acid ester is an acrylic acid ester. 3. The chloroprene polymer composition according to claim 1, wherein the α, β-unsaturated carboxylic acid ester is n-butyl acrylate. 4. A method for producing a chloroprene polymer composition, which comprises mixing a polymer emulsion of an α, β-unsaturated carboxylic acid ester having an average particle diameter of 100 nm or less with a chloroprene polymer latex.