JPH08208957A - Chloroprene rubber composition and its production - Google Patents

Abstract

PURPOSE: To obtain a chloroprene rubber compsn. which is excellent in processibility and gives a vulcanizate with an improved stiffness without detriment to its elongation at break by mixing a chloroprene rubber with a polyester. CONSTITUTION: This compsn. comprises a chloprene rubber and a polyester usually in a wt. ratio of about (100:1)-(100:50) and is prepd. pref. by mixing a chloroprene rubber latex with a water-base polyester dispersion. Examples of the polyester usable are a polyalkylene terephthalate, a polyalkylene isophthalate, a polyalkylene ether terephthalate, and a polyalkylene ether isophthalate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chloroprene rubber composition excellent in rigidity and processability of a vulcanized product and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, chloroprene rubber has a good balance of physical properties such as general rubber physical properties, weather resistance, heat resistance and chemical resistance, so that it can be used in a wide range of fields such as general industrial rubber products, automobile parts and adhesives. in use. However, in recent years, the environment in which rubber products are used has become harsh,
Conventional chloroprene rubber is becoming difficult to handle. For example, in a rubber hose of an automobile rubber component, if the wall thickness is reduced to reduce the weight of the rubber hose, the deformation due to the internal pressure or the external pressure applied to the rubber hose becomes large, which is a problem. Therefore, in such a case, it is necessary to increase the stress for deformation, that is, the rigidity.

As a method for increasing the rigidity of chloroprene rubber, a method of filling a large amount of a reinforcing filler such as carbon black, a method of adding a thermoplastic high styrene resin or a phenol resin, a thermosetting phenolic resin A method of adding, etc. is known.

However, when a large amount of the reinforcing filler is blended, the viscosity of the rubber compound becomes too high, which causes a problem in processing, and there is a problem that the elongation at break of the vulcanized product is greatly reduced. In addition, in the method of adding a thermoplastic resin, it is necessary to mix a large amount in order to increase the rigidity, but the large amount of the compound softens the resin at a high temperature, and conversely decreases the rigidity. In addition, in the method of adding a thermosetting phenolic resin or the like, the viscosity of the rubber compound does not increase so much, and the rigidity is increased at both room temperature and high temperature, but early vulcanization during molding, so-called scorch is likely to occur. Have a problem.

[0005]

DISCLOSURE OF THE INVENTION The present invention has solved the above drawbacks, and improves the rigidity of the vulcanized product without impairing the elongation at break, and the chloroprene rubber composition having excellent processability, and a method for producing the same. Is to establish.

[0006]

That is, the present invention relates to a chloroprene rubber composition prepared by mixing polyester with chloroprene rubber and a method for producing the same, wherein the polyester is polyalkylene terephthalate, polyalkylene isophthalate or polyalkylene. A chloroprene rubber composition comprising at least one selected from the group consisting of ether terephthalate and polyalkylene ether isophthalate, and mixing a chloroprene rubber latex with an aqueous dispersion of polyester, and a method for producing the same.

The chloroprene rubber in the present invention means 2
-Chloro-1,3-butadiene (hereinafter referred to as chloroprene) alone or a polymer or copolymer obtained by polymerizing chloroprene and one or more monomers copolymerizable with chloroprene.

Examples of the monomer copolymerizable with chloroprene of the present invention include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene,
Examples thereof include isoprene, sulfur, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and if necessary, two or more kinds can be used.

Polymerization of chloroprene alone or a mixture of chloroprene and a monomer copolymerizable with chloroprene in the present invention may be carried out by any known method, but the method of radical polymerization in an aqueous emulsion is the most general, It is also simple.

The emulsifier used in the aqueous emulsion polymerization is not particularly limited as long as it is generally used in the emulsion polymerization of chloroprene. For example, anionic emulsifiers such as rosin acid salts, fatty acid salts and alkylbenzene sulfonates, nonionic emulsifiers such as alkyl polyethylene glycols and polyvinyl alcohol, and cationic emulsifiers such as quaternary ammonium salts can be used. But,
Preferred are anionic emulsifiers such as rosin acid salts and fatty acid salts.

The polymerization temperature in the present invention can be freely set, but is preferably in the range of 0 to 55 ° C. At temperatures lower than 0 ° C., water coagulation becomes a problem, and at temperatures higher than 55 ° C., pressure equipment is required due to the vapor pressure of chloroprene.

The molecular weight of chloroprene rubber can be controlled by using a chain transfer agent. The chain transfer agent may be a general one, and for example, alkyl mercaptans such as dodecyl mercaptan, xanthogen disulfides such as diethyl xanthogen disulfide, halogenated hydrocarbons such as iodoform, and the like can be used.

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

The polyester used in the present invention is a polycondensation product of a polyhydric alcohol and a polybasic acid. Examples of polyhydric alcohols are ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 2,2-dimethyl-1,
3-propanediol and the like can be mentioned, and examples of the polybasic acid include phthalic acid, terephthalic acid, isophthalic acid, their esters and acid chlorides and the like.

The method of mixing chloroprene rubber and polyester includes a method of mixing an aqueous dispersion of polyester with a latex of chloroprene rubber, a method of kneading a solid polymer, a method of mixing solutions dissolved in an organic solvent, and the like. Although any method may be used, a method of mixing an aqueous dispersion of polyester with chloroprene rubber latex is preferable. This method is a simple method because a uniform mixture can be obtained by stirring for a short time.

The mixing amount of the polyester in the present invention is
Although it is appropriately used in a wide range, it is usually in the range of 1 to 50 parts by weight, and further in the range of 5 to 20 parts by weight with respect to 100 parts by weight of the chloroprene rubber. If the amount of polyester mixed is too large or too small, the physical properties such as tensile strength may be impaired.

[0017]

EXAMPLES The present invention will be described in detail with reference to examples. In the following description, parts and% are based on weight.

Example 1 Water was added in a 3 liter glass Kolben under a nitrogen stream.
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 radical polymerization initiator, and when the monomer addition rate reached 65%, tertiary butyl catechol and thiodiphenylamine were added to terminate the polymerization, The reaction monomer was removed under reduced pressure to obtain a chloroprene rubber latex.

To 100 parts of the chloroprene rubber latex (solid content), 5 parts of the polyester aqueous dispersion shown in Table 1 (solid content) was added with stirring, and the mixture was thoroughly stirred and then freeze-coagulated and dried. A chloroprene rubber composition was obtained.

Next, the chloroprene rubber composition was kneaded with the various compounding chemicals shown in Table 1 by an open roll to obtain a rubber compound (unvulcanized rubber), which was press-vulcanized at 175 ° C. for 15 minutes to give a thickness of A vulcanized sheet having a size of 2 mm was obtained (vulcanized rubber).

Example 2 Example 2 was repeated except that the mixing ratio of the polyester water dispersion shown in Table 1 was changed to 10 parts (solid content conversion).

Example 3 Example 3 was repeated except that the mixing ratio of the polyester aqueous dispersion shown in Table 1 was changed to 20 parts (solid content conversion).

Example 4 Example 4 was repeated except that the mixing ratio of the polyester aqueous dispersion shown in Table 1 was changed to 20 parts (solid content conversion).

Comparative Example 1 To 100 parts of a chloroprene polymer obtained by independently finishing the chloroprene rubber latex synthesized in Example 1,
Kneading various compounding chemicals shown in Table 1 with an open roll,
A physical property test was conducted in the same manner as in Example 1.

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out except that 65 parts of carbon was added to 100 parts of chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1.

Comparative Example 3 100 parts of chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1 was kneaded with 10 parts of the thermosetting phenolic resin shown in Table 1 and various compounding chemicals by an open roll. Then, the physical property test was performed in the same manner as in Example 1.

Comparative Example 4 To 100 parts of chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1, 20 parts of thermosetting phenolic resin shown in Table 1 and various compounding chemicals were kneaded by an open roll. Then, the physical property test was performed in the same manner as in Example 1.

Comparative Example 5 100 parts of the chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1 was kneaded with 10 parts of the high styrene resin shown in Table 2 and various compounding chemicals by an open roll. A physical property test was conducted in the same manner as in Example 1.

Comparative Example 6 100 parts of the chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1 was kneaded with 10 parts of the thermoplastic amino resin shown in Table 2 and various chemicals by an open roll, A physical property test was conducted in the same manner as in Example 1.

Comparative Example 7 To 100 parts of chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1, 10 parts of the thermosetting alkylphenol resin shown in Table 2 and various compounding chemicals were kneaded by an open roll. A physical property test was conducted in the same manner as in Example 1.

Comparative Example 8 100 parts of the chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1 was kneaded with 10 parts of the thermoplastic terpene phenol resin shown in Table 2 and various compounding chemicals by an open roll. A physical property test was conducted in the same manner as in Example 1.

Comparative Example 9 100 parts of the chloroprene rubber obtained by independently finishing the chloroprene rubber latex synthesized in Example 1 was kneaded with 10 parts of the thermoplastic phenol resin shown in Table 2 and various chemicals by an open roll, A physical property test was conducted in the same manner as in Example 1.

The physical properties of the unvulcanized rubber and the vulcanized rubber obtained in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Tables 3 and 4. 1) Method for measuring physical properties of unvulcanized rubber A) Viscosity of unvulcanized rubber: The Mooney viscosity (ML1 + 4 (100 ° C.)) of unvulcanized rubber was measured according to JIS-K6300. B) Scorch time: Scorch time (t5, ML 125 ° C.) was measured according to JIS-K6300. 2) Measurement of physical properties of vulcanized rubber A) Physical properties at room temperature; measured according to JIS-K6301.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

As described above, the chloroprene rubber composition of the present invention has improved rigidity (100% tensile stress) without impairing the scorch of unvulcanized rubber and the elongation at break of the vulcanized product. It is preferably used for various purposes such as shoes, boots and belts.

Claims (4)

[Claims] 1. A chloroprene rubber composition obtained by mixing polyester with chloroprene rubber. 2. The chloroprene rubber composition according to claim 1, wherein the polyester is one or more selected from the group consisting of polyalkylene terephthalate, polyalkylene isophthalate, polyalkylene ether terephthalate and polyalkylene ether isophthalate. 3. A method for producing a chloroprene rubber composition, which comprises mixing an aqueous dispersion of polyester with chloroprene rubber latex. 4. An aqueous dispersion of polyester is polyalkylene terephthalate, polyalkylene isophthalate,
1 selected from the group consisting of polyalkylene ether terephthalate and polyalkylene ether isophthalate
The method for producing a chloroprene rubber composition according to claim 3, which is an aqueous dispersion of at least one kind.