JP3290712B2 - Method for producing chloroprene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a chloroprene-based polymer, which comprises conducting polymerization in the presence of a polythiol compound. And this polymer shows high rigidity and is suitable for applications such as automobile boots, hoses and belts.

[0002]

2. Description of the Related Art Chloroprene-based polymers have been used in various applications because of their good balance of physical properties such as general rubber properties, heat resistance, cold resistance and chemical resistance. However, in recent years, in applications such as boots and belts for automobiles, the stress applied to the rubber material has become larger, and the accompanying deformation of the rubber material under high stress has become a problem. Therefore, there is a demand for these rubber materials that have little deformation even under high stress, that is, have high rigidity.

In general, as a method for increasing the rigidity of a rubber material, a method of adding a reinforcing agent such as carbon black is known. However, in this method, due to excessive addition of the reinforcing agent, the fatigue properties, since it causes a decrease in cold resistance, etc.,
The amount added is naturally limited, and therefore, improvement of the chloroprene-based polymer itself is desired.

In producing a chloroprene-based polymer,
Usually, a chain transfer agent such as alkyl mercaptan or dialkyl xanthogen disulfide is added for controlling the molecular weight. However, the chloroprene polymer obtained by this method is not at a satisfactory level in terms of rigidity.

[0005]

An object of the present invention is to obtain a chloroprene polymer having high rigidity represented by tensile stress.

[0006]

[Means for Solving the Problems] The present inventors have conducted various studies to achieve this object, and as a result, have found that a chloroprene polymer polymerized using a specific chain transfer agent exhibits high rigidity. This has led to the present invention.

That is, the present invention is a method for producing a chloroprene polymer, which comprises polymerizing a chloroprene monomer as a main monomer in the presence of a polythiol compound.

The chloroprene polymer in the present invention is a homopolymer of 2-chloro-1,3-butadiene or 2
-Refers to a copolymer of chloro-1,3-butadiene and other monomers.

Here, the other monomer is 2-chloro-
There is no particular limitation as long as it can be copolymerized with 1,3-butadiene.Examples include styrene, acrylonitrile, 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, acrylic acid, and acrylic acid. Esters, methacrylic acid, methacrylic esters, isoprene, 1,3-butadiene and the like can be mentioned.

The polythiol compound referred to in the present invention may be any compound having two or more thiol groups in the molecule, for example, alkylene dithiol having two or more carbon atoms, di (2-mercaptoethyl) ether, p -Xylylenedithiol and the like.

The method for polymerizing the chloroprene-based polymer of the present invention is not particularly limited, and may be any of emulsion polymerization, solution polymerization, etc., but is generally emulsion polymerization.

[0012]

The present invention will be described below in detail with reference to examples.

Example 1 A four-necked flask of 5 was used as a reactor, 1,6-hexanedithiol was used as a polythiol compound in a polymerization recipe shown in Table 1, and potassium persulfate was used at a polymerization temperature of 40 ° C. under a nitrogen atmosphere. Was continuously dropped to perform emulsion polymerization. When the conversion of the monomer reached 65%, the polymerization reaction was stopped by adding 100 ppm of diethylhydroxylamine to all the charged monomers, and the unreacted monomer was removed using a steam stripping method. did. Next, the obtained polymer was kneaded with an open roll kneader according to the compounding recipe shown in Table 3, and then vulcanized by press vulcanization at 141 ° C. for 25 minutes in accordance with JIS K-6301. Then, a normal physical property test was performed. Table 1 shows the test results.

Example 2 Polymerization and tests were conducted in the same manner as in Example 1 except that 0.14 parts by weight of 1,10-decanedithiol was used instead of 1,6-hexanedithiol. Table 1 shows the test results.

Comparative Example 1 Polymerization and tests were carried out in the same manner as in Example 1 except that 0.17 parts by weight of n-dodecyl mercaptan was used instead of the polythiol compound. Table 1 shows the test results.

Example 3 Di (2) was used as a polythiol compound in the polymerization recipe shown in Table 2.
Polymerization and tests were carried out in the same manner as in Example 1 using (-mercaptoethyl) ether. Table 2 shows the test results.

Comparative Example 2 Polymerization and tests were carried out in the same manner as in Example 3 except that 0.22 parts by weight of n-dodecyl mercaptan was used instead of di (2-mercaptoethyl) ether. Table 2 shows the test results.

[0018]

From the above results, it can be seen that the vulcanizate of the chloroprene-based polymer of the present invention has a large tensile stress and high rigidity.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

Claims (1)

(57) [Claims] 1. A method for producing a chloroprene polymer, comprising polymerizing a chloroprene monomer as a main monomer in the presence of a polythiol compound.