JP2009197127A - Chloroprene rubber composition and chloroprene rubber molded article formed form the chloroprene rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chloroprene rubber composition excellent in flowability during the molding process. <P>SOLUTION: The chloroprene rubber composition comprises at least a chloroprene polymer produced by adding a crosslinking accelerator when the polymerization is stopped. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chloroprene rubber composition. More specifically, the present invention relates to a chloroprene rubber composition having excellent fluidity during molding.

  Chloroprene polymer is a material that excels in heat resistance, weather resistance, ozone resistance, chemical resistance, flame resistance (self-extinguishing), etc., and much more than natural rubber and other synthetic resins. Has excellent properties. As described above, chloroprene polymers having balanced physical properties are used in various applications, and are used in a wide range of fields such as general industrial rubber products, automotive parts, and adhesives.

In particular, the chloroprene polymer is often used for outdoor use such as a wiper blade by utilizing the friction resistance and wear resistance of the chloroprene polymer. For example, Patent Documents 1 and 2 disclose wiper blades using a chloroprene rubber composition.
JP-A-8-319375. JP-A-10-35419.

  However, the chloroprene rubber composition generally has a problem of low fluidity and poor moldability. Accordingly, the main object of the present invention is to provide a chloroprene rubber composition having excellent fluidity during molding.

As a result of intensive studies, the inventors of the present invention surprisingly use a chloroprene polymer that can be obtained by adding a crosslinking accelerator at the time of termination of polymerization to provide a chloroprene rubber composition having excellent fluidity during molding. As a result, they have reached the present invention.
That is, the present invention provides a chloroprene rubber composition containing at least a chloroprene polymer that can be obtained by adding a crosslinking accelerator when polymerization is stopped. By adding a crosslinking accelerator when the polymerization is stopped, a chloroprene rubber composition having excellent fluidity during molding can be obtained.
In the present invention, the term “chloroprene polymer” refers to a homopolymer of 2-chloro-1,3-butadiene (hereinafter referred to as “chloroprene”) used for polymerization, or a copolymer of chloroprene and the chloroprene. It refers to a copolymer composed of other monomers. The copolymer includes those composed of two or more types of monomers.
The method for adding the crosslinking accelerator is not particularly limited, but it is preferable to add the crosslinking accelerator in a mixture with a polymerization terminator. By adding the crosslinking accelerator to the polymerization terminator, it is desirable that the crosslinking accelerator can be distributed throughout the polymerization at the same time as the polymerization is terminated, and the number of steps can be reduced from the viewpoint of productivity. desirable.
The type of the crosslinking accelerator is not particularly limited, but is preferably a thiuram compound. By using a thiuram compound as the crosslinking accelerator, it is desirable because the fluidity during molding of the resulting chloroprene rubber composition is further improved.
Next, the present invention provides a chloroprene rubber molded article comprising the chloroprene rubber composition according to the present invention. Since the chloroprene rubber composition according to the present invention is excellent in fluidity during molding, a molded product can be easily obtained.
Although the molding method of the chloroprene rubber molding according to the present invention is not particularly limited, it can be suitably molded by injection molding because of excellent fluidity during molding.
Moreover, the chloroprene rubber molded body according to the present invention is suitably used as a wiper blade.

  According to the present invention, a chloroprene rubber composition having excellent fluidity during molding can be provided.

  Hereinafter, preferred embodiments for carrying out the present invention will be described. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly.

  The chloroprene rubber composition according to the present invention contains at least a chloroprene polymer that can be obtained by adding a crosslinking accelerator when polymerization is stopped. Hereinafter, the specific structure of the chloroprene polymer used for the chloroprene rubber composition according to the present invention will be described.

  The chloroprene polymer used in the chloroprene rubber composition according to the present invention is a chloroprene homopolymer or a copolymer composed of chloroprene and another monomer copolymerizable with the chloroprene.

  The other monomer used in the present invention is not particularly limited as long as it is a monomer copolymerizable with a chloroprene monomer. For example, 2,3-dichloro-1,3-butadiene, 1-chloro- 1,3-butadiene, sulfur, styrene, acrylonitrile, methacrylonitrile, isoprene, butadiene, acrylic acid, methacrylic acid or esters thereof, and the like, and can be used as long as the characteristics inherent to the chloroprene polymer are not impaired. . In particular, 2,3-dichloro-1,3-butadiene, 1-chloro1-1,3-butadiene, and isoprene are preferably used.

  As a polymerization method of the chloroprene polymer according to the present invention, for example, known polymerization methods such as emulsion polymerization, suspension polymerization, bulk polymerization and the like can be used, but it is preferable to use emulsion polymerization. By using emulsion polymerization, the heat of polymerization is quickly removed, and post-treatment is facilitated, which is desirable.

  When the chloroprene polymer according to the present invention is obtained by emulsion polymerization, a chloroprene monomer, or chloroprene and other monomers copolymerizable with the chloroprene, are used as an emulsifier, a dispersant, a polymerization initiator, a chain transfer agent. Polymerization in the presence of the like.

  The kind of emulsifier used in this case is not particularly limited, and an emulsifier generally used for emulsion polymerization of chloroprene can be used. Specific examples include, for example, saturated or unsaturated fatty acid alkali metal salts having 6 to 22 carbon atoms, alkali metal salts of rosin acid or disproportionated rosin acid, β-naphthalenesulfonic acid formalin condensate alkali metal salts, and the like. It is done. Furthermore, wood rosin acid, gum rosin acid, tall oil rosin acid, disproportionated rosin acid disproportionated from these rosin acids, alkali metal salts of these rosin acids, and the like can be used. Although the usage-amount of an emulsifier is not specifically limited, 0.5-10 mass parts is preferable with respect to 100 weight part of monomers, More preferably, it is 2-6 mass parts. The addition of an emulsifier in the above range is desirable because the monomer can be sufficiently emulsified.

  The type of polymerization initiator used in the polymerization reaction is not particularly limited, and inorganic peroxides such as potassium persulfate, ammonium persulfate, sodium persulfate, sodium peroxide, hydrogen peroxide, and t-butyl hydroperoxide And organic peroxides such as dialkyl peroxides can be used.

In the present invention, a serial transfer agent can be used. The type of chain transfer agent used is not particularly limited. For example, an aliphatic mercaptan compound such as n-dodecyl mercaptan, a xanthogen disulfide compound such as tert-dodecylpropyl xanthogen disulfide, diisopropyl xanthogen disulfide, or diethyl xanthogen disulfide is used. Can do.
The amount of chain transfer agent used is not particularly limited, but is selected so that the molecular weight of the chloroprene polymer (or the Mooney viscosity of the chloroprene rubber obtained by isolating the polymer) is appropriate. Although it varies depending on the structure of the alkyl group and the target molecular weight, it is generally 0.05 to 5.0 parts by weight, preferably 0.3 to 1.0 parts by weight with respect to 100 parts by weight of the chloroprene monomer. Used.

  The polymerization temperature of the chloroprene polymer according to the present invention is not particularly limited, but the lower limit of the polymerization temperature is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, and the upper limit of the polymerization temperature is preferably Is preferably 59 ° C. or lower, more preferably 50 ° C. or lower. By setting the polymerization temperature to be equal to or higher than the lower limit, the emulsion does not coagulate, which is desirable. Moreover, it is desirable to set the polymerization temperature to be equal to or lower than the upper limit of the polymerization temperature because the monomer does not reach the boiling point and the polymerization can be performed without requiring a pressure-resistant facility.

  In the present invention, when the polymerization reaction reaches a desired polymerization rate, the polymerization reaction of chloroprene is stopped, but this stopping method is not particularly limited. For example, a polymerization stopper is added or the reaction temperature is changed. It can be stopped by, for example.

  The kind of the polymerization terminator used in the present invention is not particularly limited, and examples thereof include amine compounds such as phenothiazine and thiodiphenylamine, 4-tert-butylcatechol, 2,2′-methylene (bis-4-methyl-6). Phenolic compounds such as (-tert-butylphenol) can be used.

  The polymerization terminator can be added by a usual method, for example, it can be added after being dissolved in an organic solvent or monomer, or can be added directly.

  In the present invention, the polymerization rate of the chloroprene polymer is not particularly limited, but the lower limit of the polymerization rate is preferably 30%, more preferably 50%, and the upper limit of the polymerization rate is preferably 95%. %, More preferably 80%. By setting the lower limit of the polymerization rate of the chloroprene polymer to the above value, the mechanical properties of the chloroprene polymer, particularly the friction resistance and wear resistance, can be sufficiently obtained. Further, setting the upper limit to the above value is desirable because the fluidity during molding does not deteriorate.

  The chloroprene polymer according to the present invention is characterized in that a crosslinking accelerator is added when the polymerization is stopped. In the present invention, “when the polymerization is stopped” includes not only simultaneously with the operation for stopping the polymerization but also immediately before and after the operation for stopping the polymerization. This includes the case where a crosslinking accelerator is added immediately before, the case where a crosslinking accelerator is added immediately after the addition of a polymerization terminator, and the like.

  The crosslinking accelerator to be added is not particularly limited, and for example, thiuram compounds, thiourea compounds, aldehyde amine compounds, sulfenamide compounds, thiazole compounds, guanidine compounds and the like can be used. System compounds are desirable.

  Specific examples of thiuram compounds include, for example, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetraisopropylthiuram disulfide, tetra-n-butylthiuram disulfide, tetraoctylthiuram disulfide, tetrakis (2-ethylhexyl). ) Thiuram disulfide, dipentamethylene thiuram tetrasulfide and the like, and tetraethylthiuram disulfide is preferably used.

  The amount of the crosslinking accelerator to be added is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.3 parts by weight with respect to 100 parts by weight of the monomer. The amount is preferably 2 parts by weight or less.

  The method for adding the crosslinking accelerator is not particularly limited. For example, it can be added after being dissolved in an organic solvent or a monomer, or it can be added directly, but it is preferable to add it in a polymerization terminator. It is. It is desirable to add the cross-linking accelerator to the polymerization terminator, so that the cross-linking accelerator can be distributed throughout the polymerization at the same time as the polymerization is terminated. It is desirable because it can be done. Furthermore, the fluidity at the time of shaping | molding of the obtained chloroprene rubber composition can be improved by mixing and adding a crosslinking accelerator to a polymerization terminator.

  As post-treatment after the polymerization reaction, unreacted monomers and the like can be removed by exposure to high temperature by, for example, a steam stripping method or a concentration method. And about the chloroprene polymer from which the said unreacted monomer etc. were removed, acidity is adjusted to neutrality. As the neutralizing agent used in this case, for example, an aqueous solution of an acidic substance such as acetic acid or methacrylic acid, an aqueous solution of a basic substance such as caustic soda, potassium hydroxide, or sodium carbonate can be used. Furthermore, the chloroprene polymer can be isolated by a treatment such as freezing and coagulation, washing with water and drying with hot air.

  In addition to the chloroprene polymer, the chloroprene rubber composition according to the present invention includes other rubber components, crosslinking agents, crosslinking accelerators, reinforcing agents, fillers, processing aids, anti-aging agents, softeners, lubricants, and the like. Various additives can be contained as appropriate.

  The chloroprene rubber composition according to the present invention contains at least the above chloroprene polymer, but can appropriately contain rubber components such as natural rubber, butyl rubber, butadiene rubber, nitrile rubber, and ethylene propylene rubber as necessary.

  As the crosslinking agent used in the chloroprene rubber composition according to the present invention, those generally used can be used. Specific examples include, for example, elemental elements such as beryllium, magnesium, zinc, calcium, barium, germanium, titanium, tin, zirconium, antimony, vanadium, bismuth, molybdenum, tungsten, tellurium, selenium, iron, nickel, cobalt, osmium, and the like. Oxides and hydroxides of the above elements can be used.

  As a suitable crosslinking agent used for the chloroprene rubber composition according to the present invention, calcium oxide, zinc oxide, antimony dioxide, antimony trioxide, and magnesium oxide are desirable. These crosslinking agents can be used alone or in combination of two or more. The addition amount of the crosslinking agent is not particularly limited, but is preferably 2 to 20 parts by weight with respect to 100 parts by weight of the chloroprene polymer.

  In order to advance the crosslinking reaction more efficiently, a crosslinking accelerator can be added to the chloroprene rubber composition according to the present invention separately from the one added when the polymerization of the chloroprene polymer is stopped. The crosslinking accelerator used is not particularly limited, and for example, thiuram compounds, thiourea compounds, aldehyde amine compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, etc. may be used alone or in combination. it can. Moreover, the same thing as the crosslinking accelerator added at the time of the polymerization stop of a chloroprene polymer may be used, and a different thing may be used. In particular, thiourea compounds such as ethylenethiourea, diethylthiourea, trimethylthiourea, triethylthiourea, and N, N′-diphenylthiourea are preferably used. Although the addition amount of a crosslinking accelerator is not specifically limited, It is suitable to set it as 0.5-5 weight part.

  As the reinforcing agent used in the chloroprene rubber composition according to the present invention, those generally used can be used. By containing a reinforcing agent, the mechanical strength can be increased. The reinforcing agent used is not particularly limited, and for example, carbon black, silica and the like can be used alone or in combination. The addition amount of the reinforcing agent is not particularly limited, but is preferably 20 to 80 parts by weight with respect to 100 parts by weight of the chloroprene polymer.

  As the filler used in the chloroprene rubber composition according to the present invention, those generally used can be used. The filler used is not particularly limited, and for example, carbon black, calcium carbonate, clay, talc and the like can be used alone or in combination. Although the addition amount of a filler is not specifically limited, It is suitable to set it as 30-100 weight part with respect to 100 weight part of chloroprene polymers.

  As the processing aid used in the chloroprene rubber composition according to the present invention, those generally used can be used. By containing a processing aid, processability can be improved. The processing aid used is not particularly limited, and for example, fatty acids such as stearic acid can be used alone or in combination. The amount of processing aid added is not particularly limited, but is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the chloroprene polymer. By setting the amount of the processing aid to be in the above range, the processability and the like can be improved without impairing the mechanical properties and the like of the resulting chloroprene rubber.

  As the anti-aging agent used in the chloroprene rubber composition according to the present invention, those generally used can be used. The anti-aging agent used is not particularly limited. For example, amine compounds such as diphenylamine, imidazole compounds such as 2-mercaptobenzimidazole, carbamic acid metal salts such as nickel diethyldithiocarbamate, 2,2′-methylene-bis- ( 4-methyl-6-tert-butylphenol) and the like, waxes generally used for rubber compounding, etc. can be used alone or in combination. The addition amount of the antiaging agent is not particularly limited, but is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the chloroprene polymer. By making the addition amount of the anti-aging agent within the above range, it is desirable because aging can be prevented without impairing the mechanical properties of the resulting chloroprene rubber composition.

  As the softener used in the chloroprene rubber composition according to the present invention, those generally used can be used. The softener used is not particularly limited. For example, petroleum softeners such as lubricating oil, process oil, paraffin, liquid paraffin, petroleum jelly, petroleum asphalt, vegetable softener such as rapeseed oil, linseed oil, castor oil, coconut oil, etc. An agent or the like can be used alone or in combination. The addition amount of the softening agent is not particularly limited, but is preferably 0 to 100 parts by weight with respect to 100 parts by weight of the chloroprene polymer. By making the addition amount of the softening agent within the above range, it is desirable because the mechanical properties of chloroprene rubber can be maintained.

  As the lubricant used in the chloroprene rubber composition according to the present invention, those generally used can be used. The lubricant to be used is not particularly limited, and for example, paraffin wax such as liquid paraffin, fatty acid such as stearic acid, fatty acid amide, fatty acid ester and the like can be used alone or in combination. The addition amount of the softening agent is not particularly limited, but is preferably 0 to 100 parts by weight with respect to 100 parts by weight of the chloroprene polymer. By setting the amount of the lubricant to be in the above range, it is preferable because the adhesion of the polymer to the inner wall of the processing machine can be prevented and the molding process can be facilitated.

The chloroprene rubber composition according to the present invention is excellent in fluidity during molding, and is 100 ° C., a load of 9.8 × 10 ² N / cm ² (100 kgf / cm ² ), a die hole diameter of 1 mm, a die It is particularly preferable that the flow rate under the condition of a length of 1 mm is 100 cm ² / s or more. It is desirable for the flow rate under the above conditions to be 100 cm ² / s or more because the molding process by injection molding can be performed more easily. The flow rate is a scale indicating the fluidity of the polymer, and is an index indicating the amount flowing out from a nozzle (orifice) having a specified size under a constant pressure and a constant temperature.

  The chloroprene rubber composition according to the present invention can be kneaded by a kneader such as a kneader, a Banbury mixer, a mixing roll, etc. in the same manner as a general rubber, and can be formed into a shape according to the purpose to be a molded body. Although the molding method in this case is not particularly limited, injection molding is preferably used because the chloroprene rubber composition according to the present invention is excellent in fluidity at the time of molding.

  As a method for crosslinking the chloroprene rubber molded article according to the present invention, a general method can be used, for example, press crosslinking, injection crosslinking, direct kettle crosslinking, indirect kettle crosslinking, direct steam continuous crosslinking, atmospheric pressure continuous crosslinking, continuous A crosslinking press, electron beam crosslinking, or the like can be used.

  The chloroprene rubber molded body according to the present invention is suitably used as a wiper blade, for example.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example.

< Production of chloroprene polymer >
<Production Example 1>
In a 5 L flask, 100 parts by weight of monomer (97.5 parts by weight of chloroprene and 2.5 parts by weight of 2,3-dichlorobutadiene), 115 parts by weight of pure water, 3 parts by weight of potassium rosinate, β-naphthalenesulfone 0.4 parts by weight of acid formalin condensate sodium salt was added. 0.1 parts by weight of potassium persulfate was added as a polymerization initiator, and polymerization was performed at a polymerization temperature of 50 ° C. under a nitrogen stream. When the polymerization rate reached 56.1%, the polymerization terminator t-butylcatechol 0.02 parts by weight, phenothiazine 0.02 parts by weight and thiuram-based crosslinking accelerator (tetraethylthiuram disulfide Ouchi Shinsei Chemical Co., Ltd. Noxeller TET) 0.5 parts by weight of the mixture was added to stop the polymerization.
Next, unreacted monomers and the like were removed by a conventional steam trap method, and the obtained latex was dried by a freeze coagulation drying method. The obtained chloroprene polymer was designated as Production Example 1.

< Measurement of Mooney viscosity >
About the chloroprene polymer which concerns on manufacture example 1, the Mooney viscosity in 100 degreeC was measured based on JIS-K6300.
The Mooney viscosity of the chloroprene polymer according to Production Example 1 was 33.4.

<Production Example 2>
A chloroprene polymer was produced in the same procedure as in Production Example 1 except that the thiuram crosslinking accelerator was 1.0 part by weight and the polymerization rate was 56.2%.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 2 was 34.8.

<Production Example 3>
3.5 parts by weight of potassium rosinate, 94 parts by weight of chloroprene and 6 parts by weight of 2,3-dichlorobutadiene, 0.5 part by weight of tetraoctylthiuram disulfide as a thiuram crosslinking accelerator, and a polymerization rate A chloroprene polymer was produced in the same procedure as in Production Example 1 except that the content was 59.1%.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 3 was 40.5.

<Production Example 4>
A chloroprene polymer is produced in the same manner as in Production Example 1 except that the thiuram-based crosslinking accelerator is 0.5 parts by weight of dipentamethylene thiuram tetrasulfide, the polymerization temperature is 40 ° C., and the polymerization rate is 62.8%. did.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 4 was 44.5.

<Production Example 5>
Except that the monomer was 94 parts by weight of chloroprene and 6 parts by weight of 2,3-dichlorobutadiene, the thiuram crosslinking accelerator was 0.5 part by weight of tetramethylthiuram monosulfide, and the polymerization rate was 61.1%. A chloroprene polymer was produced in the same procedure as in Production Example 1.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 5 was 37.3.

<Production Example 6>
The production example 1 except that the thiuram crosslinking accelerator is 0.5 parts by weight of a thiourea crosslinking accelerator (trimethylthiourea; Noxeller TMU manufactured by Ouchi Shinsei Chemical Co., Ltd.) and the polymerization rate is 63.5%. A chloroprene polymer was produced in the same procedure.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 6 was 39.1.

<Production Example 7>
The thiuram crosslinking accelerator was 0.5 parts by weight of an aldehyde amine crosslinking accelerator (reaction product of n-butyraldehyde and aniline; Noxeller 8 manufactured by Ouchi Shinsei Chemical Co., Ltd.), and the polymerization rate was 62.9%. A chloroprene polymer was produced in the same procedure as in Production Example 1 except for the above point.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 7 was 41.1.

<Production Example 8>
A chloroprene polymer is produced in the same manner as in Production Example 1 except that the thiuram-based crosslinking accelerator is 0.5 part by weight of N-oxydiethylenebenzothiazole-2-sulfenamide and the polymerization rate is 59.5%. did.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 8 was 38.3.

<Production Example 9>
A chloroprene polymer was produced by the same procedure as in Production Example 1 except that the thiuram crosslinking accelerator was 0.5 parts by weight of 2-morpholinodithiobenzothiazole and the polymerization rate was 61.1%.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 9 was 44.1.

<Production Example 10>
Production Example except that potassium rosinate is 3.5 parts by weight, the monomers are 94 parts by weight and 6 parts by weight of chloroprene, no crosslinking accelerator is added when the polymerization terminator is added, and the polymerization rate is 62.6%. A chloroprene polymer was produced by the same procedure as in 1.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 10 was 43.8.

<Production Example 11>
Chloroprene was prepared in the same manner as in Production Example 1 except that potassium rosinate was 3.5 parts by weight, no crosslinking accelerator was added when the polymerization terminator was added, the polymerization temperature was 40 ° C., and the polymerization rate was 60.8%. A polymer was produced.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 11 was 42.9.

<Production Example 12>
A chloroprene polymer was produced in the same procedure as in Production Example 1 except that no crosslinking accelerator was added when the polymerization terminator was added and the polymerization rate was 62.9%.
When the Mooney viscosity was measured by the same method as in Production Example 1, the Mooney viscosity of the chloroprene polymer according to Production Example 12 was 44.9.

  Table 1 shows the polymerization conditions of each production example and the Mooney viscosity of the obtained chloroprene polymer.

< Preparation of chloroprene rubber composition >
<Example 1>
For 100 parts by weight of the chloroprene polymer according to Production Example 1, 1.0 part by weight of stearic acid, 2.0 parts by weight of octylated diphenylamine, 4.0 parts by weight of magnesium oxide, 25.0 parts by weight of carbon black (FEF), 5.0 parts by weight of plasticizer (Shinsocizer DUP, manufactured by Shinnippon Chemical Co., Ltd.), 1.0 part by weight of thiourea-based vulcanization accelerator (ethylene thiourea; Accelerator 22S, manufactured by Kawaguchi Chemical Industry Co., Ltd.) (Tetraethyl thiuram disulfide; Nouchira TET, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.0 part by weight and 5.0 parts by weight of zinc oxide were mixed using an 8-inch roll, and chloroprene was press-crosslinked at 160 ° C. for 30 minutes. A rubber composition was obtained.

<Example 2 to Example 9>
A chloroprene rubber composition was obtained in the same manner as in Example 1 except that the chloroprene polymer according to Production Example 2 to Production Example 9 was used. Each obtained chloroprene rubber composition was made into Example 2-9.

<Comparative Examples 1-3>
The chloroprene polymer according to Production Example 10 to Production Example 11 was obtained in the same manner as in Example 1 to obtain a chloroprene rubber composition. The obtained chloroprene rubber compositions were referred to as Comparative Examples 1 to 3.

< Measurement of Mooney viscosity >
About the chloroprene rubber composition which concerns on each Example and each comparative example, the Mooney viscosity in 100 degreeC was measured based on JIS-K6300.

< Measurement of scorch time >
About the chloroprene rubber composition which concerns on each Example and each comparative example, the scorch time in 125 degreeC was measured based on JIS-K6300.

< Measurement of flow rate >
Using a flow tester CFT-500C manufactured by Shimadzu Corporation, the flow rate was measured under the conditions of a sample temperature of 100 ° C., a load of 100 kgf / cm ² , a die hole diameter of 1 mm, and a die length of 1 mm.

  Table 2 shows the composition of each Example and each Comparative Example and the measurement results of Mooney viscosity, scorch time and flow rate of the resulting chloroprene rubber composition.

The chloroprene rubber compositions according to the examples all showed a high flow rate and were confirmed to be excellent in fluidity during molding.

Claims (6)

  A chloroprene rubber composition comprising at least a chloroprene polymer that can be obtained by adding a crosslinking accelerator when polymerization is stopped.   The chloroprene rubber composition according to claim 1, wherein the crosslinking accelerator is added in a mixture with a polymerization terminator.   The chloroprene rubber composition according to claim 1 or 2, wherein the crosslinking accelerator is a thiuram compound.   A chloroprene rubber molded article comprising the chloroprene rubber composition according to any one of claims 1 to 3.   The chloroprene rubber molded article according to claim 4, which is molded by injection molding.   The chloroprene rubber molded body according to claim 4 or 5, wherein the molded body is a wiper blade.