WO2020095961A1 - Chloroprene rubber composition and vulcanization molded body - Google Patents

Chloroprene rubber composition and vulcanization molded body Download PDF

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Publication number
WO2020095961A1
WO2020095961A1 PCT/JP2019/043550 JP2019043550W WO2020095961A1 WO 2020095961 A1 WO2020095961 A1 WO 2020095961A1 JP 2019043550 W JP2019043550 W JP 2019043550W WO 2020095961 A1 WO2020095961 A1 WO 2020095961A1
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mass
parts
chloroprene rubber
chloroprene
rubber composition
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PCT/JP2019/043550
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French (fr)
Japanese (ja)
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敦典 近藤
貴史 砂田
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デンカ株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/14—Peroxides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
    • C08K5/45—Heterocyclic compounds having sulfur in the ring
    • C08K5/46—Heterocyclic compounds having sulfur in the ring with oxygen or nitrogen in the ring
    • C08K5/47—Thiazoles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L11/00—Compositions of homopolymers or copolymers of chloroprene
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/10—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with non-metallic packing

Definitions

  • the present invention relates to a chloroprene rubber composition containing a chloroprene rubber, a specific sulfur compound and an organic peroxide, and a vulcanized molded product of the chloroprene rubber composition.
  • Chloroprene rubber composition is widely used as a material for industrial rubber products because of its excellent mechanical properties and flame retardancy, and various improvements have been made.
  • Patent Document 1 discloses a technology of chloroprene rubber having an improved vulcanization rate.
  • Patent Documents 2 to 4 disclose the technology of chloroprene rubber having improved heat resistance.
  • JP 2001-181451 A JP, 2009-275124, A JP, 2010-106227, A JP, 2005-060546, A
  • One aspect of the present invention when obtaining a vulcanized molded body by vulcanization molding, improve the vulcanization rate while maintaining the compression set of the vulcanized body and suppressing the decrease in elongation at break after heat aging.
  • An object is to provide a chloroprene rubber composition that can be used.
  • Another object of another aspect of the present invention is to provide a vulcanized molded product that can be obtained by vulcanizing this chloroprene rubber composition.
  • One aspect of the present invention comprises 100 parts by mass of a chloroprene rubber, 0.5 to 5.0 parts by mass of a sulfur-based compound represented by the following general formula (1), and more than 4 parts by mass of an organic peroxide.
  • a chloroprene rubber composition containing 0.0 part by mass or less.
  • R 1 represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 8 carbon atoms
  • R 2 and R 3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • One aspect of the present invention provides a vulcanized molded product of the above chloroprene rubber composition.
  • the vulcanization rate in obtaining a vulcanized molded article by vulcanization molding, while maintaining the compression set of the vulcanized molded article and suppressing the decrease in elongation at break after heat aging, the vulcanization rate It is possible to provide a chloroprene rubber composition capable of improving the above.
  • a vulcanized molded article obtained by vulcanizing and molding this chloroprene rubber composition is suitable as a vulcanized molded article for automobile rubber members (seal materials, etc.), hoses (hose materials), rubber molds, gaskets, etc. Can be used.
  • the numerical range indicated by using “to” indicates the range including the numerical values before and after “to” as the minimum value and the maximum value, respectively.
  • the upper limit value or the lower limit value of the numerical range of a certain stage can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another stage.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
  • the materials exemplified in the present specification can be used alone or in combination of two or more kinds.
  • the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.
  • the chloroprene rubber composition according to the present embodiment contains 100 parts by mass of a chloroprene rubber, 0.5 to 5.0 parts by mass of a specific sulfur compound described below, and 4.0 parts by mass of more than 0 parts by mass of organic peroxide. And less than or equal to parts by mass.
  • the chloroprene rubber composition according to the present embodiment when the chloroprene rubber composition is vulcanized and molded to obtain a vulcanized molded body, the compression set of the vulcanized molded body is maintained (the compression set is kept low). At the same time, it is possible to improve (accelerate) the vulcanization rate while suppressing a decrease in elongation at break after heat aging.
  • the vulcanized product according to the present embodiment is a vulcanized product of the chloroprene rubber composition according to the present embodiment, and can be obtained by vulcanizing the chloroprene rubber composition according to the present embodiment.
  • the chloroprene rubber is a chloroprene polymer (for example, chloroprene latex) having a structural unit derived from chloroprene (2-chloro-1,3-butadiene).
  • the chloroprene polymer is a homopolymer of chloroprene, a copolymer of chloroprene (a copolymer of a monomer copolymerizable with chloroprene and chloroprene), and a mixture of these polymers.
  • Examples of monomers copolymerizable with chloroprene include acrylic acid esters such as methyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; methacrylic acid such as methyl methacrylate, butyl methacrylate and 2-ethylhexyl methacrylate.
  • the monomer copolymerizable with chloroprene one type may be used alone, or two or more types may be used in combination.
  • the monomer copolymerizable with chloroprene may be, for example, a polymer obtained by copolymerizing three or more kinds of monomers containing chloroprene. Also, the polymer structure of the polymer is not particularly limited.
  • Chloroprene-based rubber is chloroprene alone from the viewpoint of easily maintaining a low compression set of the vulcanized molded body, from the viewpoint of easily improving the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging.
  • the polymer includes at least one selected from a polymer and a chloroprene copolymer, and the chloroprene copolymer is at least one selected from chloroprene and 2,3-dichloro-1,3-butadiene and acrylonitrile.
  • An embodiment including a copolymer with a monomer is preferable.
  • the chloroprene rubber is a homopolymer of 2-chloro-1,3-butadiene, or is selected from 2-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene and acrylonitrile. It is preferably a copolymer with at least one monomer.
  • the content (copolymerization amount) of the structural unit derived from chloroprene is the compression set of the vulcanized product.
  • the following range is preferable for 100 parts by mass of the chloroprene rubber from the viewpoints of easily maintaining the low value, easily improving the vulcanization rate, and easily suppressing a decrease in elongation at break after heat aging.
  • the content of the structural unit derived from chloroprene is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, further preferably 80 parts by mass or more, particularly preferably 90 parts by mass or more, and very preferably It is 95 parts by mass or more, very preferably 97 parts by mass or more, and even more preferably 98 parts by mass or more.
  • the content of the structural unit derived from chloroprene is less than 100 parts by mass, preferably 99.5 parts by mass or less, more preferably 99.2 parts by mass or less, and further preferably 99 parts by mass or less. From these viewpoints, the content of the structural unit derived from chloroprene is preferably 50 parts by mass or more and less than 100 parts by mass.
  • the content of the structural unit derived from the monomer copolymerizable with chloroprene is 100 parts by mass of the structural unit derived from chloroprene, or 100 parts by mass of the chloroprene rubber, from the viewpoint of easily exhibiting the effect of copolymerizing these monomers without impairing the properties of the obtained chloroprene rubber composition.
  • the following range is preferable.
  • the content of the structural unit is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, particularly preferably 10 parts by mass or less, and very preferably 5 parts by mass. Or less, very preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less.
  • the content of the structural unit is more than 0 parts by mass, preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, still more preferably 1 part by mass or more. From these viewpoints, the content of the structural unit is preferably more than 0 parts by mass and 50 parts by mass or less.
  • the method for producing chloroprene rubber includes a polymerization step of polymerizing a raw material monomer containing chloroprene.
  • Chloroprene-based rubber is used as an emulsifying dispersant, for example, in the presence of a catalyst for polymerization reaction, a catalyst activator, a polymerization initiator, a chain transfer agent, etc. It can be obtained by emulsion-polymerizing a raw material monomer as a component).
  • an alkali metal salt of a saturated or unsaturated fatty acid having 6 to 22 carbon atoms an rosin acid or an alkali metal salt of disproportionated rosin acid (eg potassium rosinate), formalin of ⁇ -naphthalenesulfonic acid
  • alkali metal salts for example, sodium salts
  • the catalyst for the polymerization reaction examples include inorganic peroxides such as potassium sulfate; organic peroxides such as ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides and diacyl peroxides. ..
  • catalyst activator examples include sodium sulfite, potassium sulfite, iron (II) oxide, anthraquinone, sodium ⁇ -sulfonate, formamidine sulfonic acid and L-ascorbic acid.
  • the polymerization initiator is not particularly limited, and a known polymerization initiator generally used for emulsion polymerization of a chloroprene monomer (a chloroprene monomer) can be used.
  • examples of the polymerization initiator include potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide, t-butyl hydroperoxide and the like.
  • the chain transfer agent is also not particularly limited, and it is possible to use the one used for ordinary emulsion polymerization of chloroprene.
  • chain transfer agents include long-chain alkyl mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan; xanthogen compounds such as diisopropylxanthogen disulfide and diethylxanthogen disulfide; iodoform; benzyl 1-pyrrole dithiocarbamate (alias).
  • Benzyl 1-pyrrole carbodithioate benzyl phenyl carbodithioate, 1-benzyl-N, N-dimethyl-4-aminodithiobenzoate, 1-benzyl-4-methoxydithiobenzoate, 1-phenylethylimidazole dithiocarbamate (alias) 1-phenylethylimidazole carbodithioate), benzyl-1- (2-pyrrolidinone) dithiocarbamate (also known as benzyl-1- (2-pyrrolidinone)) Rubodithioate), benzylphthalimidyldithiocarbamate (also known as benzylphthalimidylcarbodithioate), 2-cyanoprop-2-yl-1-pyrroledithiocarbamate (also known as 2-cyanoprop-2-yl-1-pyrrolecarbodithioate) , 2-Cyanobut-2-yl-1-pyrroledithi
  • the polymerization temperature of the chloroprene rubber is not particularly limited, and is generally 0 to 50 ° C., more preferably 20 to 50 ° C., as the temperature at which emulsion polymerization is performed.
  • the final polymerization rate of the chloroprene rubber obtained in the above-mentioned polymerization step is not particularly limited, but it is preferably adjusted within the range of 30 to 100%.
  • the polymerization can be stopped by adding a polymerization terminator that stops the polymerization reaction when the desired conversion is reached.
  • the polymerization terminator is not particularly limited, and a commonly used polymerization terminator can be used.
  • Specific examples of the polymerization terminator include phenothiazine (thiodiphenylamine), 4-tert-butylcatechol, and 2,2-methylenebis-4-methyl-6-tert-butylphenol.
  • the method is not particularly limited, and examples thereof include a steam stripping method.
  • the pH is adjusted, and the chloroprene rubber can be obtained through processes such as freeze-coagulation, washing with water, and drying with hot air in a usual manner.
  • the chloroprene rubber composition according to the present embodiment contains a sulfur-based compound represented by the following general formula (1) (hereinafter referred to as "specific sulfur-based compound").
  • the specific sulfur compound can accelerate vulcanization of the resulting chloroprene rubber composition.
  • R 1 represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 8 carbon atoms
  • R 2 and R 3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • the hydrogen atom of the alkyl group of R 1 , R 2 and R 3 may be substituted with a substituent.
  • R 1 is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • the alkyl group of R 1 preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 or 2 carbon atoms.
  • R 2 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
  • R 3 is preferably a hydrogen atom.
  • Specific examples of the specific sulfur compound include 4-methylthiazolidine-2-thione, 3-methylthiazolidine-2-thione, 5-methylthiazolidine-2-thione, 3,4-dimethylthiazolidine-2-thione, 4, 5-dimethylthiazolidine-2-thione, 3,5-dimethylthiazolidine-2-thione, 3,4,5-trimethylthiazolidine-2-thione, 4-ethyl-3-thiazolidine-2-thione, 4-isopropyl-3 -Thiazolidine-2-thione, 4-isopropyl-3-methylthiazolidine-2-thione, 4-hydroxythiazolidine-2-thione, 5-ethyl-3-thiazolidine-2-thione, 5-isopropyl-3-thiazolidine-2 -Thion, 5-isopropyl-3-methylthiazolidine-2-thione, 5-hydroxythiazo -2-thione, 3-ethyl-thiazolidine-2-thione, 3-propyl thiazolidine-2-thione,
  • the specific sulfur compound is 4- It preferably contains at least one selected from methylthiazolidine-2-thione, 3-methylthiazolidine-2-thione, and 4-isopropyl-3-methylthiazolidine-2-thione.
  • the specific sulfur compounds can be used alone or in combination of two or more.
  • the content of the specific sulfur compound is 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the chloroprene rubber. If the content of the specific sulfur compound is less than 0.5 parts by mass, the effect of promoting vulcanization of the obtained chloroprene rubber composition is low and the vulcanization rate cannot be improved. In addition, elongation upon cutting after heat aging may decrease and compression set may deteriorate. If the content of the specific sulfur compound exceeds 5.0 parts by mass, the rubber elasticity of the obtained vulcanized molded article is lost, the elongation at break after heat aging is reduced, and the compression set is deteriorated. It may happen.
  • the content of the specific sulfur compound is preferably 0.75 parts by mass or more, more preferably 1.0 parts by mass or more, from the viewpoint of easily improving the vulcanization rate.
  • the content of the specific sulfur-based compound is preferably 4.5 parts by mass or less, from the viewpoint of easily suppressing a decrease in elongation at break after heat aging, and from the viewpoint of easily keeping the compression set of the vulcanized molded product low.
  • the content of the specific sulfur compound is preferably 0.75 to 3.0 parts by mass, more preferably 1.0 to 2.0 parts by mass.
  • the content of the specific sulfur-based compound is preferably more than 1.0 part by mass, more preferably 1.5 parts by mass or more, and further preferably 2.0 parts by mass, from the viewpoint that the vulcanization rate is more easily improved.
  • the content of the specific sulfur-based compound from the viewpoint of easily maintaining a low compression set of the vulcanized molded article, from the viewpoint of easily improving the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging.
  • the total amount of the sulfur-based compound (the total amount of the sulfur-based compound contained in the chloroprene rubber composition according to the present embodiment), it is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably Is 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 99% by mass or more.
  • the sulfur-based compound in the chloroprene rubber composition according to the present embodiment may be substantially composed of the specific sulfur-based compound (substantially 100% by mass of the sulfur-based compound is the specific sulfur-based compound).
  • the chloroprene rubber composition according to this embodiment may contain a sulfur-based compound other than the specific sulfur-based compound.
  • a sulfur compound for example, a vulcanization accelerator generally used for vulcanizing chloroprene rubber can be used.
  • the vulcanization accelerator include thiourea-based, guanidine-based, thiuram-based, thiazole-based vulcanization accelerators; dimethylammonium hydrogen isophthalate; 1,2-dimercapto-1,3,4-thiadiazole derivative and the like. ..
  • Examples of the thiourea-based vulcanization accelerator include ethylenethiourea, diethylthiourea, trimethylthiourea, triethylthiourea, N, N'-diphenylthiourea, and the like, and at least one selected from trimethylthiourea and ethylenethiourea is preferable.
  • the sulfur compounds may be used alone or in combination of two or more.
  • the content of the sulfur-based compound (the total amount of the sulfur-based compound contained in the chloroprene rubber composition according to this embodiment) is preferably in the following range with respect to 100 parts by mass of the chloroprene rubber.
  • the content of the sulfur-based compound is preferably 0.5 parts by mass or more, more preferably 0.75 parts by mass or more, and further preferably 1.0 parts by mass or more, from the viewpoint of easily improving the vulcanization rate. Is.
  • the content of the sulfur-based compound is preferably 5.0 parts by mass or less from the viewpoint of easily suppressing a decrease in elongation at break after heat aging, and from the viewpoint of easily keeping the compression set of the vulcanized molded product low.
  • the content of the sulfur-based compound is preferably 0.5 to 5.0 parts by mass.
  • the content of the sulfur-based compound is preferably more than 1.0 part by mass, more preferably 1.5 parts by mass or more, and further preferably 2.0 parts by mass or more, from the viewpoint of further improving the vulcanization rate.
  • the chloroprene rubber composition according to the present embodiment contains an organic peroxide.
  • the organic peroxide can accelerate the vulcanization of the obtained chloroprene rubber composition by a synergistic effect with the above-mentioned specific sulfur compound.
  • organic peroxide examples include dialkyl peroxide, diacyl peroxide, peroxyketal, peroxyester, and butyl 4,4-bis [(t-butyl) peroxy] pentanoate.
  • the organic peroxide is a dialkylperoxide from the viewpoint of easily keeping the compression set of the vulcanized molded article low, from the viewpoint of easily increasing the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. It preferably contains at least one selected from oxides, peroxyketals and butyl 4,4-bis [(t-butyl) peroxy] pentanoate.
  • dialkyl peroxides examples include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne. -3,1,3-bis (t-butylperoxyisoprobyl) benzene, 1,4-bis (t-butylperoxyisoprobyl) benzene, t-butylcumyl peroxide, di-t-butylperoxide, etc. Is mentioned.
  • the dialkyl peroxides can be used alone or in combination of two or more.
  • diacyl peroxide examples include dibenzoyl peroxide, di-p-methylbenzoyl peroxide, di-o-methylbenzoyl peroxide and the like.
  • the diacyl peroxides can be used alone or in combination of two or more.
  • peroxyketals examples include 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane, n-butyl-4,4-di (t-butylperoxy) valerate and the like.
  • the peroxyketals may be used alone or in combination of two or more.
  • peroxyesters examples include 2,5-dimethyl-2,5-di (t-benzoylperoxy) hexane, t-hexylperoxybenzoate, t-butylperoxybenzoate and the like.
  • the peroxyesters may be used alone or in combination of two or more.
  • the content of organic peroxide is more than 0 parts by mass and 4.0 parts by mass or less based on 100 parts by mass of chloroprene rubber.
  • the content of the organic peroxide is 0 part by mass, the effect of promoting vulcanization of the obtained chloroprene rubber composition is low and the vulcanization rate cannot be improved.
  • elongation upon cutting after heat aging may decrease and compression set may deteriorate.
  • the content of the organic peroxide exceeds 4.0 parts by mass, the rubber elasticity of the obtained vulcanized molded product may be lost, and the elongation at break after heat aging may be reduced.
  • the content of the organic peroxide is from the viewpoint of easily keeping the compression set of the vulcanized molded article low, from the viewpoint of easily increasing the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging.
  • the content of the organic peroxide is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and further preferably from the viewpoint of easily suppressing a decrease in elongation at break after heat aging.
  • the content of the organic peroxide is preferably 0.05 to 4.0 parts by mass, more preferably 0.1 to 3.0 parts by mass, still more preferably 0.1 to 3.0 parts by mass.
  • the amount is 2.0 parts by mass, and particularly preferably 0.3 to 1.0 part by mass.
  • the content of the organic peroxide is preferably 0.75 parts by mass or more, from the viewpoint of easily maintaining the compression set of the vulcanized molded article even lower and from the viewpoint of further improving the vulcanization rate, and It is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, particularly preferably 2.0 parts by mass or more, very preferably 2.5 parts by mass or more, and very preferably Is 3.0 parts by mass or more.
  • the chloroprene rubber composition according to the present embodiment may contain a filler or a reinforcing agent, a plasticizer, a vulcanizing agent, a vulcanization aid, a processing aid, an antioxidant, and the like.
  • filler or reinforcing agent examples include carbon black, silica, clay, talc, calcium carbonate and the like. Each of the filler and the reinforcing agent may be used alone or in combination of two or more.
  • the content of the filler or the reinforcing agent is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
  • the plasticizer is not particularly limited as long as it is compatible with chloroprene rubber, vegetable oil (rapeseed oil, etc.), phthalate plasticizer, DOS, DOA, ester plasticizer, ether / ester plasticizer, Examples include thioether plasticizers, aromatic oils, naphthene oils and the like.
  • the plasticizer may be used alone or in combination of two or more, depending on the properties required for the chloroprene rubber composition.
  • the content of the plasticizer is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
  • the vulcanizing agent is not particularly limited, but a metal oxide is preferable. Specific examples of the metal oxide include zinc oxide, magnesium oxide, lead oxide, trilead tetroxide, iron trioxide, titanium dioxide, calcium oxide, hydrotalcite and the like.
  • the vulcanizing agents may be used alone or in combination of two or more.
  • the content of the vulcanizing agent is preferably 3 to 15 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition. Vulcanization can be performed more effectively by using a vulcanizing agent in combination with the above-mentioned vulcanization accelerator.
  • the chloroprene rubber composition according to the present embodiment as a vulcanization aid, at least one selected from a difunctional ester compound and a trifunctional ester compound from the viewpoint of improving the vulcanization rate or vulcanization density. Can be included.
  • vulcanization aid examples include trimethylolpropane, ethylene glycol dimethacrylate, triallyl isocyanate, triallyl cyanate, and maleimide compounds.
  • the vulcanization aids may be used alone or in combination of two or more.
  • maleimide compounds include N-cyclohexylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, 2-methyl-N-phenylmaleimide, 2,3-dimethylmaleimide, 2 -Ethyl maleimide, 2-n-butyl maleimide, N-benzyl maleimide, N, N'-1,2-ethyl bismaleimide, N, N'-1,2-hexyl bismaleimide, N-propionic acid maleimide, 4, 4'-bismaleimidodiphenylmethane, 6,7-methylenedioxy-4-methyl-3-coumaric acid maleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, N-bromomethyl-2,3- Dichloromaleimide, N- (3-maleimidobenzoyloxy) succinic acid, N (3-maleimido
  • the content of the vulcanization aid is preferably in the following range with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
  • the content of the vulcanization aid is preferably 0.2 parts by mass or more, and more preferably 0.5 parts by mass or more, from the viewpoint of easily obtaining the effect of adding the vulcanization aid.
  • the content of the vulcanization aid is preferably 5 parts by mass or less, and more preferably 4 parts by mass or less, from the viewpoint of easily suppressing the hardness of the obtained vulcanized product from becoming excessively high. From these viewpoints, the content of the vulcanization aid is preferably 0.2 to 5 parts by mass, more preferably 0.5 to 4 parts by mass.
  • processing aids include fatty acids such as stearic acid; paraffin-based processing aids such as polyethylene; fatty acid amides.
  • the processing aids may be used alone or in combination of two or more.
  • the content of the processing aid is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
  • an amine antiaging agent an imidazole antiaging agent, a carbamate metal salt, a phenol antiaging agent, a wax, an ozone antiaging agent (for example, N-phenyl-N '-(1,3- Dimethylbutyl) -p-phenylenediamine) and the like.
  • the anti-aging agent is preferably an amine-based anti-aging agent from the viewpoint of a large effect of improving heat resistance, and at least one selected from 4,4′-bis ( ⁇ , ⁇ -dimethylbenzyl) diphenylamine and octylated diphenylamine. Is more preferable, and 4,4′-bis ( ⁇ , ⁇ -dimethylbenzyl) diphenylamine is even more preferable.
  • the antioxidants can be used alone or in combination of two or more.
  • the chloroprene rubber composition according to the present embodiment may contain phenothiazine from the viewpoint of improving the processing stability of the chloroprene rubber composition.
  • the content of phenothiazine is preferably 0.1 to 2 parts by mass, more preferably 0.3 to 1.5 parts by mass based on 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition. .. By using phenothiazine in these ranges, the effect of improving the processing stability of the obtained chloroprene rubber composition is high.
  • the chloroprene rubber composition according to the present embodiment can be obtained by kneading the above compound at a temperature below its vulcanization temperature.
  • a mixer, a Banbury mixer, a kneader mixer, a two-roll mill or the like can be used as the kneading device.
  • the molded body according to this embodiment is a molded body of the chloroprene rubber composition according to this embodiment, and can be obtained by molding the chloroprene rubber composition according to this embodiment.
  • the vulcanized molded product according to the present embodiment is a vulcanized molded product of the chloroprene rubber composition according to the present embodiment.
  • a method for molding a vulcanized molded body from the chloroprene rubber composition a method such as press molding, extrusion molding or calender molding can be used.
  • the temperature for vulcanizing the chloroprene rubber composition may be set appropriately according to the composition, and is preferably 140 to 220 ° C, more preferably 150 to 180 ° C.
  • the vulcanization time may also be appropriately set depending on the composition or shape of the chloroprene rubber composition, and may be 10 to 60 minutes.
  • the vulcanized molded article according to the present embodiment is obtained by vulcanizing and molding the chloroprene rubber composition according to the present embodiment, and its compression set is maintained despite the high vulcanization rate. At the same time, the decrease in elongation at break after heat aging was suppressed.
  • the polymerization rate of the chloroprene-acrylonitrile copolymer latex was calculated from the dry mass of the chloroprene-acrylonitrile copolymer latex air-dried. Specifically, it was calculated by the following formula (I).
  • the solid content concentration means the concentration of solid content obtained by heating 2 g of sampled chloroprene-acrylonitrile copolymer latex at 130 ° C. and removing volatile components such as solvent (water), volatile chemicals and raw materials [mass %].
  • the total amount charged is the total amount of raw materials, reagents and solvent (water) charged in a polymerization vessel from the start of polymerization to a certain time.
  • the evaporation residue is the mass of the chemicals and raw materials charged from the start of the polymerization to a certain time and remaining as a solid content together with the polymer without being volatilized under the condition of 130 ° C.
  • the monomer charging amount is the total of the amount of the monomer initially charged in the polymerization vessel and the amount of the monomer added by a certain time from the start of polymerization.
  • the "monomer” referred to here is the total amount of the chloroprene monomer and the acrylonitrile monomer.
  • Polymerization rate [%] ⁇ (total charged amount [g] ⁇ solid content concentration [mass%] / 100) ⁇ (evaporation residue [g]) ⁇ / monomer charged amount [g] ⁇ 100 ( I)
  • a sheet was obtained by adjusting the pH of the above-mentioned chloroprene-acrylonitrile copolymer latex to pH 7.0 and freeze-coagulating it on a metal plate cooled to -20 ° C to break the emulsion. The sheet was washed with water and then dried at 130 ° C. for 15 minutes to obtain a solid chloroprene-acrylonitrile copolymer rubber.
  • the number-average molecular weight (Mn), weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the chloroprene-acrylonitrile copolymer rubber are the same as those of the chloroprene-acrylonitrile copolymer rubber in a sample adjusted concentration of 0.1 mass% with THF. After that, it was measured by a high-speed GPC device (TOSOH HLC-8320GPC: manufactured by Tosoh Corporation) (standard polystyrene conversion).
  • the TSK guard column HHR-H was used as a pre-column, three HSKgel GMHHR-H were used as an analytical column, and the sample pump pressure was 8.0 to 9.5 MPa, the flow rate was 1 ml / min, and the flow rate was 40 ° C. It was detected by the total.
  • the amount of structural units derived from the unsaturated nitrile monomer contained in the chloroprene-acrylonitrile copolymer rubber was calculated from the content of nitrogen atoms in the chloroprene-acrylonitrile copolymer rubber. Specifically, the nitrogen atom content of 100 mg of chloroprene-acrylonitrile copolymer rubber was measured using an elemental analyzer (Sumigraph 220F: manufactured by Sumika Analytical Center Co., Ltd.), and the structural unit derived from the acrylonitrile monomer was measured. Calculated. The elemental analysis was performed under the following conditions. The electric furnace temperature was set to 900 ° C. for the reaction furnace, 600 ° C. for the reduction furnace, 70 ° C. for the column temperature, and 100 ° C. for the detector temperature. .. The calibration curve was prepared using aspartic acid (10.52%) with a known nitrogen content as a standard substance.
  • the chloroprene-acrylonitrile copolymer rubber had a number average molecular weight (Mn) of 138 ⁇ 10 3 / mol, a weight average molecular weight (Mw) of 473 ⁇ 10 3 g / mol, and a molecular weight distribution (Mw / Mn) of 3.4. ..
  • Mn number average molecular weight
  • Mw weight average molecular weight
  • Mn molecular weight distribution
  • Sulfur-based compound A 3-methylthiazolidine-2-thione, manufactured by LANXESS, Renoglan MTT-80
  • Sulfur-based compound B 4-methylthiazolidine-2-thione (commercially available product)
  • Sulfur-based compound C 4-isopropyl-3-methylthiazolidine-2-thione (commercially available product)
  • Organic peroxide B Perbutyl (registered trademark) C-40 manufactured by NOF CORPORATION
  • Organic peroxide C Perhexa (registered trademark) 25B manufactured by NOF CORPORATION
  • A represents the elongation value at break (average value of 5 sheets) of the measurement sample before heat treatment
  • B represents the elongation value at break (average value of 5 sheets) of the measurement sample after heat treatment.
  • the case where the rate of change was between -15% and 0% was evaluated as acceptable.
  • Change rate of elongation at break after heat aging (%) (BA) / A ⁇ 100 (II)
  • vulcanized molded articles were obtained using the chloroprene rubber compositions of Examples, vulcanization was performed while maintaining compression set and suppressing the decrease in elongation at break after heat aging. It turns out that the speed is improving. Since the vulcanized molded product has these properties, it is excellent in productivity and can be suitably used as a molded product such as a rubber member for automobile (sealing material), a hose (hose material), a rubber mold, a gasket and the like.

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Abstract

A chloroprene rubber composition which contains: 100 parts by mass of a chloroprene rubber; 0.5-5.0 parts by mass of a sulfur-based compound represented by general formula (1); and more than 0 part by mass but 4.0 parts by mass or less of an organic peroxide. (In the formula, R1 represent a hydrogen atom, a hydroxyl group or an alkyl group having 1-8 carbon atoms; and each of R2 and R3 independently represents a hydrogen atom or an alkyl group having 1-8 carbon atoms.)

Description

クロロプレンゴム組成物及び加硫成形体Chloroprene rubber composition and vulcanized molded article
　本発明は、クロロプレン系ゴム、特定の硫黄系化合物及び有機過酸化物を含有するクロロプレンゴム組成物、並びに、このクロロプレンゴム組成物の加硫成形体に関する。 The present invention relates to a chloroprene rubber composition containing a chloroprene rubber, a specific sulfur compound and an organic peroxide, and a vulcanized molded product of the chloroprene rubber composition.
　クロロプレンゴム組成物は、機械特性、難燃性等に優れているため工業用ゴム製品の材料として広く用いられており、様々な改良がなされている。例えば、下記特許文献１には加硫速度を向上させたクロロプレンゴムの技術が開示されている。下記特許文献２～４には耐熱性を向上させたクロロプレンゴムの技術が開示されている。 Chloroprene rubber composition is widely used as a material for industrial rubber products because of its excellent mechanical properties and flame retardancy, and various improvements have been made. For example, Patent Document 1 below discloses a technology of chloroprene rubber having an improved vulcanization rate. The following Patent Documents 2 to 4 disclose the technology of chloroprene rubber having improved heat resistance.
特開２００１－１８１４５１号公報JP 2001-181451 A 特開２００９－２７５１２４号公報JP, 2009-275124, A 特開２０１０－１０６２２７号公報JP, 2010-106227, A 特開２００５－０６０５４６号公報JP, 2005-060546, A
　本発明の一側面は、加硫成形して加硫成形体を得るに際し、加硫成形体の圧縮永久ひずみを維持すると共に熱老化後の切断時伸びの低下を抑制しつつ加硫速度を向上させることが可能なクロロプレンゴム組成物を提供することを課題とする。本発明の他の一側面は、このクロロプレンゴム組成物を加硫して得ることが可能な加硫成形体を提供することを課題とする。 One aspect of the present invention, when obtaining a vulcanized molded body by vulcanization molding, improve the vulcanization rate while maintaining the compression set of the vulcanized body and suppressing the decrease in elongation at break after heat aging. An object is to provide a chloroprene rubber composition that can be used. Another object of another aspect of the present invention is to provide a vulcanized molded product that can be obtained by vulcanizing this chloroprene rubber composition.
　本発明の一側面は、クロロプレン系ゴム１００質量部と、下記一般式（１）で表される硫黄系化合物０．５～５．０質量部と、有機過酸化物０質量部を超えて４．０質量部以下と、を含有する、クロロプレンゴム組成物を提供する。
Figure JPOXMLDOC01-appb-C000002
 ［式中、Ｒ１は、水素原子、水酸基又は炭素数１～８のアルキル基を表し、Ｒ２及びＲ３は、それぞれ独立に、水素原子又は炭素数１～８のアルキル基を表す。］ One aspect of the present invention comprises 100 parts by mass of a chloroprene rubber, 0.5 to 5.0 parts by mass of a sulfur-based compound represented by the following general formula (1), and more than 4 parts by mass of an organic peroxide. Provided is a chloroprene rubber composition containing 0.0 part by mass or less.
Figure JPOXMLDOC01-appb-C000002
 [In the formula, R 1 represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 8 carbon atoms, and R 2 and R 3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ]
　本発明の一側面は、上述のクロロプレンゴム組成物の加硫成形体を提供する。 One aspect of the present invention provides a vulcanized molded product of the above chloroprene rubber composition.
　本発明の一側面によれば、加硫成形して加硫成形体を得るに際し、加硫成形体の圧縮永久ひずみを維持すると共に熱老化後の切断時伸びの低下を抑制しつつ加硫速度を向上させることが可能なクロロプレンゴム組成物を提供することができる。このクロロプレンゴム組成物を加硫成形することにより得られる加硫成形体は、自動車用ゴム部材（シール材等）、ホース（ホース材）、ゴム型物、ガスケットなどの加硫成形体として好適に使用することができる。本発明の他の一側面によれば、このクロロプレンゴム組成物を加硫して得ることが可能な加硫成形体を提供することができる。 According to one aspect of the present invention, in obtaining a vulcanized molded article by vulcanization molding, while maintaining the compression set of the vulcanized molded article and suppressing the decrease in elongation at break after heat aging, the vulcanization rate It is possible to provide a chloroprene rubber composition capable of improving the above. A vulcanized molded article obtained by vulcanizing and molding this chloroprene rubber composition is suitable as a vulcanized molded article for automobile rubber members (seal materials, etc.), hoses (hose materials), rubber molds, gaskets, etc. Can be used. According to another aspect of the present invention, it is possible to provide a vulcanized molded product that can be obtained by vulcanizing this chloroprene rubber composition.
　以下、本発明を実施するための形態について詳細に説明する。なお、本発明は、以下に説明する実施形態に限定されるものではない。 Hereinafter, modes for carrying out the present invention will be described in detail. The present invention is not limited to the embodiments described below.
　本明細書において、「～」を用いて示された数値範囲は、「～」の前後に記載される数値をそれぞれ最小値及び最大値として含む範囲を示す。本明細書に段階的に記載されている数値範囲において、ある段階の数値範囲の上限値又は下限値は、他の段階の数値範囲の上限値又は下限値と任意に組み合わせることができる。本明細書に記載されている数値範囲において、その数値範囲の上限値又は下限値は、実施例に示されている値に置き換えてもよい。本明細書に例示する材料は、特に断らない限り、１種を単独で又は２種以上を組み合わせて用いることができる。組成物中の各成分の含有量は、組成物中に各成分に該当する物質が複数存在する場合、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。 In the present specification, the numerical range indicated by using "to" indicates the range including the numerical values before and after "to" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of the numerical range of a certain stage can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another stage. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. Unless otherwise specified, the materials exemplified in the present specification can be used alone or in combination of two or more kinds. The content of each component in the composition means the total amount of the plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.
＜クロロプレンゴム組成物＞
　本実施形態に係るクロロプレンゴム組成物は、クロロプレン系ゴム１００質量部と、後述する特定の硫黄系化合物０．５～５．０質量部と、有機過酸化物０質量部を超えて４．０質量部以下と、を含有する。本実施形態に係るクロロプレンゴム組成物によれば、クロロプレンゴム組成物を加硫成形して加硫成形体を得るに際し、加硫成形体の圧縮永久ひずみを維持（圧縮永久ひずみを低く維持）すると共に熱老化後の切断時伸びの低下を抑制しつつ加硫速度を向上させる（速める）ことができる。本実施形態に係る加硫物は、本実施形態に係るクロロプレンゴム組成物の加硫物であり、本実施形態に係るクロロプレンゴム組成物を加硫することにより得ることができる。 <Chloroprene rubber composition>
The chloroprene rubber composition according to the present embodiment contains 100 parts by mass of a chloroprene rubber, 0.5 to 5.0 parts by mass of a specific sulfur compound described below, and 4.0 parts by mass of more than 0 parts by mass of organic peroxide. And less than or equal to parts by mass. According to the chloroprene rubber composition according to the present embodiment, when the chloroprene rubber composition is vulcanized and molded to obtain a vulcanized molded body, the compression set of the vulcanized molded body is maintained (the compression set is kept low). At the same time, it is possible to improve (accelerate) the vulcanization rate while suppressing a decrease in elongation at break after heat aging. The vulcanized product according to the present embodiment is a vulcanized product of the chloroprene rubber composition according to the present embodiment, and can be obtained by vulcanizing the chloroprene rubber composition according to the present embodiment.
（１）クロロプレン系ゴム
　クロロプレン系ゴムは、クロロプレン（２－クロロ－１，３－ブタジエン）由来の構造単位を有するクロロプレン重合体（例えばクロロプレンラテックス）である。クロロプレン重合体は、クロロプレンの単独重合体、クロロプレンの共重合体（クロロプレンと共重合可能な単量体と、クロロプレンと、の共重合体）、及び、これら重合体の混合物である。 (1) Chloroprene Rubber The chloroprene rubber is a chloroprene polymer (for example, chloroprene latex) having a structural unit derived from chloroprene (2-chloro-1,3-butadiene). The chloroprene polymer is a homopolymer of chloroprene, a copolymer of chloroprene (a copolymer of a monomer copolymerizable with chloroprene and chloroprene), and a mixture of these polymers.
　クロロプレンと共重合可能な単量体としては、アクリル酸メチル、アクリル酸ブチル、アクリル酸２－エチルヘキシル等のアクリル酸のエステル類；メタクリル酸メチル、メタクリル酸ブチル、メタクリル酸２－エチルヘキシル等のメタクリル酸のエステル類；２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシメチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート等のヒドロキシ（メタ）アクリレート類；２，３－ジクロロ－１，３－ブタジエン；１－クロロ－１，３－ブタジエン；ブタジエン；イソプレン；エチレン；スチレン；アクリロニトリルなどが挙げられる。クロロプレンと共重合可能な単量体は、１種を単独で又は２種以上を組み合わせて用いることができる。クロロプレンと共重合可能な単量体は、例えば、クロロプレンを含む３種以上の単量体を共重合して得られる重合体であってもよい。また、重合体のポリマー構造も、特に限定されるものではない。 Examples of monomers copolymerizable with chloroprene include acrylic acid esters such as methyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; methacrylic acid such as methyl methacrylate, butyl methacrylate and 2-ethylhexyl methacrylate. Esters of 2-hydroxyethyl (meth) acrylate, 2-hydroxymethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and other hydroxy (meth) acrylates; 2,3-dichloro-1,3-butadiene 1-chloro-1,3-butadiene; butadiene; isoprene; ethylene; styrene; acrylonitrile and the like. As the monomer copolymerizable with chloroprene, one type may be used alone, or two or more types may be used in combination. The monomer copolymerizable with chloroprene may be, for example, a polymer obtained by copolymerizing three or more kinds of monomers containing chloroprene. Also, the polymer structure of the polymer is not particularly limited.
　クロロプレン系ゴムは、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、クロロプレンの単独重合体、及び、クロロプレンの共重合体から選ばれる少なくとも１種を含み、クロロプレンの共重合体が、クロロプレンと、２，３－ジクロロ－１，３－ブタジエン及びアクリロニトリルから選ばれる少なくとも１種の単量体との共重合体を含む態様が好ましい。すなわち、クロロプレン系ゴムは、２－クロロ－１，３－ブタジエンの単独重合体、又は、２－クロロ－１，３－ブタジエンと、２，３－ジクロロ－１，３－ブタジエン及びアクリロニトリルから選ばれる少なくとも１種の単量体との共重合体であることが好ましい。 Chloroprene-based rubber is chloroprene alone from the viewpoint of easily maintaining a low compression set of the vulcanized molded body, from the viewpoint of easily improving the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. The polymer includes at least one selected from a polymer and a chloroprene copolymer, and the chloroprene copolymer is at least one selected from chloroprene and 2,3-dichloro-1,3-butadiene and acrylonitrile. An embodiment including a copolymer with a monomer is preferable. That is, the chloroprene rubber is a homopolymer of 2-chloro-1,3-butadiene, or is selected from 2-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene and acrylonitrile. It is preferably a copolymer with at least one monomer.
　クロロプレン系ゴムとして、クロロプレンと共重合可能な単量体と、クロロプレンと、の共重合体を用いる場合、クロロプレン由来の構造単位の含有量（共重合量）は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、クロロプレン系ゴム１００質量部に対して下記の範囲が好ましい。クロロプレン由来の構造単位の含有量は、好ましくは５０質量部以上、より好ましくは７０質量部以上であり、更に好ましくは８０質量部以上であり、特に好ましくは９０質量部以上であり、極めて好ましくは９５質量部以上であり、非常に好ましくは９７質量部以上であり、より一層好ましくは９８質量部以上である。クロロプレン由来の構造単位の含有量は、１００質量部未満であり、好ましくは９９．５質量部以下であり、より好ましくは９９．２質量部以下であり、更に好ましくは９９質量部以下である。これらの観点から、クロロプレン由来の構造単位の含有量は、好ましくは５０質量部以上１００質量部未満である。 When a copolymer of chloroprene and a monomer copolymerizable with chloroprene is used as the chloroprene rubber, the content (copolymerization amount) of the structural unit derived from chloroprene is the compression set of the vulcanized product. The following range is preferable for 100 parts by mass of the chloroprene rubber from the viewpoints of easily maintaining the low value, easily improving the vulcanization rate, and easily suppressing a decrease in elongation at break after heat aging. The content of the structural unit derived from chloroprene is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, further preferably 80 parts by mass or more, particularly preferably 90 parts by mass or more, and very preferably It is 95 parts by mass or more, very preferably 97 parts by mass or more, and even more preferably 98 parts by mass or more. The content of the structural unit derived from chloroprene is less than 100 parts by mass, preferably 99.5 parts by mass or less, more preferably 99.2 parts by mass or less, and further preferably 99 parts by mass or less. From these viewpoints, the content of the structural unit derived from chloroprene is preferably 50 parts by mass or more and less than 100 parts by mass.
　クロロプレン系ゴムとして、クロロプレンと共重合可能な単量体と、クロロプレンと、の共重合体を用いる場合、クロロプレンと共重合可能な単量体由来の構造単位の含有量（共重合量）は、得られるクロロプレンゴム組成物の特性を損なわずに、これらの単量体を共重合させたことによる効果を発現しやすい観点から、クロロプレン由来の構造単位１００質量部、又は、クロロプレン系ゴム１００質量部に対して下記の範囲が好ましい。構造単位の含有量は、好ましくは５０質量部以下、より好ましくは３０質量部以下であり、更に好ましくは２０質量部以下であり、特に好ましくは１０質量部以下であり、極めて好ましくは５質量部以下であり、非常に好ましくは３質量部以下であり、より一層好ましくは２質量部以下である。構造単位の含有量は、０質量部を超え、好ましくは０．５質量部以上であり、より好ましくは０．８質量部以上であり、更に好ましくは１質量部以上である。これらの観点から、構造単位の含有量は、好ましくは０質量部を超え５０質量部以下である。 As the chloroprene rubber, when a copolymer of chloroprene and a monomer copolymerizable with chloroprene is used, the content of the structural unit derived from the monomer copolymerizable with chloroprene (copolymerization amount) is 100 parts by mass of the structural unit derived from chloroprene, or 100 parts by mass of the chloroprene rubber, from the viewpoint of easily exhibiting the effect of copolymerizing these monomers without impairing the properties of the obtained chloroprene rubber composition. On the other hand, the following range is preferable. The content of the structural unit is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, particularly preferably 10 parts by mass or less, and very preferably 5 parts by mass. Or less, very preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less. The content of the structural unit is more than 0 parts by mass, preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, still more preferably 1 part by mass or more. From these viewpoints, the content of the structural unit is preferably more than 0 parts by mass and 50 parts by mass or less.
　クロロプレン系ゴムの製造方法は、クロロプレンを含む原料単量体を重合させる重合工程を備える。クロロプレン系ゴムは、例えば、乳化分散剤として用いて、重合反応の触媒、触媒活性化剤、重合開始剤、連鎖移動剤等の存在下で、クロロプレンを含む原料単量体（例えば、クロロプレンを主成分とする原料単量体）を乳化重合することにより得ることができる。 The method for producing chloroprene rubber includes a polymerization step of polymerizing a raw material monomer containing chloroprene. Chloroprene-based rubber is used as an emulsifying dispersant, for example, in the presence of a catalyst for polymerization reaction, a catalyst activator, a polymerization initiator, a chain transfer agent, etc. It can be obtained by emulsion-polymerizing a raw material monomer as a component).
　乳化分散剤としては、炭素数が６～２２の飽和又は不飽和の脂肪酸のアルカリ金属塩、ロジン酸又は不均化ロジン酸のアルカリ金属塩（例えばロジン酸カリウム）、β－ナフタレンスルホン酸のホルマリン縮合物のアルカリ金属塩（例えばナトリウム塩）等が挙げられる。 As the emulsifying dispersant, an alkali metal salt of a saturated or unsaturated fatty acid having 6 to 22 carbon atoms, an rosin acid or an alkali metal salt of disproportionated rosin acid (eg potassium rosinate), formalin of β-naphthalenesulfonic acid Examples thereof include alkali metal salts (for example, sodium salts) of the condensate.
　重合反応の触媒としては、硫酸カリウム等の無機過酸化物；ケトンパーオキサイド類、パーオキシケタール類、ハイドロパーオキサイド類、ジアルキルパーオキサイド類、ジアシルパーオキサイド類等の有機過酸化物などが挙げられる。 Examples of the catalyst for the polymerization reaction include inorganic peroxides such as potassium sulfate; organic peroxides such as ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides and diacyl peroxides. ..
　触媒活性化剤としては、亜硫酸ナトリウム、亜硫酸カリウム、酸化鉄（ＩＩ）、アントラキノン、β－スルフォン酸ナトリウム、フォルムアミジンスルフォン酸、Ｌ－アスコルビン酸等が挙げられる。 Examples of the catalyst activator include sodium sulfite, potassium sulfite, iron (II) oxide, anthraquinone, sodium β-sulfonate, formamidine sulfonic acid and L-ascorbic acid.
　重合開始剤としては、特に制限はなく、クロロプレン単量体（クロロプレンである単量体）の乳化重合に一般に用いられる公知の重合開始剤を用いることができる。重合開始剤としては、過硫酸カリウム、過硫酸アンモニウム、過硫酸ナトリウム、過酸化水素、ｔ－ブチルハイドロパーオキサイド等が挙げられる。 The polymerization initiator is not particularly limited, and a known polymerization initiator generally used for emulsion polymerization of a chloroprene monomer (a chloroprene monomer) can be used. Examples of the polymerization initiator include potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide, t-butyl hydroperoxide and the like.
　連鎖移動剤も、特に限定されるものではなく、通常のクロロプレンの乳化重合に使用されるものを使用することができる。連鎖移動剤としては、ｎ－ドデシルメルカプタン、ｔ－ドデシルメルカプタン、ｎ－オクチルメルカプタン等の長鎖アルキルメルカプタン類；ジイソプロピルキサントゲンジスルフィド、ジエチルキサントゲンジスルフィド等のキサントゲン化合物；ヨードホルム；ベンジル１－ピロールジチオカルバメート（別名ベンジル１－ピロールカルボジチオエート）、ベンジルフェニルカルボジチオエート、１－ベンジル－Ｎ，Ｎ－ジメチル－４－アミノジチオベンゾエート、１－ベンジル－４－メトキシジチオベンゾエート、１－フェニルエチルイミダゾールジチオカルバメート（別名１－フェニルエチルイミダゾールカルボジチオエート）、ベンジル－１－（２－ピロリジノン）ジチオカルバメート（別名ベンジル－１－（２－ピロリジノン）カルボジチオエート）、ベンジルフタルイミジルジチオカルバメート（別名ベンジルフタルイミジルカルボジチオエート）、２－シアノプロプ－２－イル－１－ピロールジチオカルバメート（別名２－シアノプロプ－２－イル－１－ピロールカルボジチオエート）、２－シアノブト－２－イル－１－ピロールジチオカルバメート（別名２－シアノブト－２－イル－１－ピロールカルボジチオエート）、ベンジル－１－イミダゾールジチオカルバメート（別名ベンジル－１－イミダゾールカルボジチオエート）、２－シアノプロプ－２－イル－Ｎ，Ｎ－ジメチルジチオカルバメート、ベンジル－Ｎ，Ｎ－ジエチルジチオカルバメート、シアノメチル－１－（２－ピロリドン）ジチオカルバメート、２－（エトキシカルボニルベンジル）プロプ－２－イル－Ｎ，Ｎ－ジエチルジチオカルバメート、１－フェニルエチルジチオベンゾエート、２－フェニルプロプ－２－イルジチオベンゾエート、１－酢酸－１－イル－エチルジチオベンゾエート、１－（４－メトキシフェニル）エチルジチオベンゾエート、ベンジルジチオアセテート、エトキシカルボニルメチルジチオアセタート、２－（エトキシカルボニル）プロプ－２－イルジチオベンゾエート、２－シアノプロプ－２－イルジチオベンゾエート、ｔ－ブチルジチオベンゾエート、２，４，４－トリメチルペンタ－２－イルジチオベンゾエート、２－（４－クロロフェニル）－プロプ－２－イルジチオベンゾエート、３－ビニルベンジルジチオベンゾエート、４－ビニルベンジルジチオベンゾエート、ベンジルジエトキシホスフィニルジチオフォルマート、ｔ－ブチルトリチオペルベンゾエート、２－フェニルプロプ－２－イル－４－クロロジチオベンゾエート、ナフタレン－１－カルボン酸－１－メチル－１－フェニル－エチルエステル、４－シアノ－４－メチル－４－チオベンジルスルファニル酪酸、ジベンジルテトラチオテレフタラート、カルボキシメチルジチオベンゾエート、ジチオベンゾエート末端基を持つポリ（酸化エチレン）、４－シアノ－４－メチル－４－チオベンジルスルファニル酪酸末端基を持つポリ（酸化エチレン）、２－［（２－フェニルエタンチオイル）スルファニル］プロパン酸、２－［（２－フェニルエタンチオイル）スルファニル］コハク酸、３，５－ジメチル－１Ｈ－ピラゾール－１－カルボジチオエートカリウム、シアノメチル－３，５－ジメチル－１Ｈ－ピラゾール－１－カルボジチオエート、シアノメチルメチル－（フェニル）ジチオカルバメート、ベンジル－４－クロロジチオベンゾエート、フェニルメチル－４－クロロジチオベンゾエート、４－ニトロベンジル－４－クロロジチオベンゾエート、フェニルプロプ－２－イル－４－クロロジチオベンゾエート、１－シアノ－１－メチルエチル－４－クロロジチオベンゾエート、３－クロロ－２－ブテニル－４－クロロジチオベンゾエート、２－クロロ－２－ブテニルジチオベンゾエート、ベンジルジチオアセテート、３－クロロ－２－ブテニル－１Ｈ－ピロール－１－ジチオカルボン酸、２－シアノブタン－２－イル－４－クロロ－３，５－ジメチル－１Ｈ－ピラゾール－１－カルボジチオエート、シアノメチルメチル（フェニル）カルバモジチオエート、２－シアノ－２－プロピルドデシルトリチオカルボナート、ジベンジルトリチオカルボナート、ブチルベンジルトリチオカルボナート、２－［［（ブチルチオ）チオキソメチル］チオ］プロピオン酸、２－［［（ドデシルチオ）チオキソメチル］チオ］プロピオン酸、２－［［（ブチルチオ）チオキソメチル］チオ］コハク酸、２－［［（ドデシルチオ）チオキソメチル］チオ］コハク酸、２－［［（ドデシルチオ）チオキソメチル］チオ］－２－メチルプロピオン酸、２，２’－［カルボノチオイルビス（チオ）］ビス［２－メチルプロピオン酸］、２－アミノ－１－メチル－２－オキソエチルブチルトリチオカルボナート、ベンジル－２－［（２－ヒドロキシエチル）アミノ］－１－メチル－２－オキソエチルトリチオカルボナート、３－［［［（ｔ－ブチル）チオ］チオキソメチル］チオ］プロピオン酸、シアノメチルドデシルトリチオカルボナート、ジエチルアミノベンジルトリチオカルボナート、ジブチルアミノベンジルトリチオカルボナート等のチオカルボニル化合物などが挙げられる。 The chain transfer agent is also not particularly limited, and it is possible to use the one used for ordinary emulsion polymerization of chloroprene. Examples of chain transfer agents include long-chain alkyl mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan; xanthogen compounds such as diisopropylxanthogen disulfide and diethylxanthogen disulfide; iodoform; benzyl 1-pyrrole dithiocarbamate (alias). Benzyl 1-pyrrole carbodithioate), benzyl phenyl carbodithioate, 1-benzyl-N, N-dimethyl-4-aminodithiobenzoate, 1-benzyl-4-methoxydithiobenzoate, 1-phenylethylimidazole dithiocarbamate (alias) 1-phenylethylimidazole carbodithioate), benzyl-1- (2-pyrrolidinone) dithiocarbamate (also known as benzyl-1- (2-pyrrolidinone)) Rubodithioate), benzylphthalimidyldithiocarbamate (also known as benzylphthalimidylcarbodithioate), 2-cyanoprop-2-yl-1-pyrroledithiocarbamate (also known as 2-cyanoprop-2-yl-1-pyrrolecarbodithioate) , 2-Cyanobut-2-yl-1-pyrroledithiocarbamate (also known as 2-cyanobut-2-yl-1-pyrrolecarbodithioate), benzyl-1-imidazoledithiocarbamate (also known as benzyl-1-imidazolecarbodithioate) , 2-cyanoprop-2-yl-N, N-dimethyldithiocarbamate, benzyl-N, N-diethyldithiocarbamate, cyanomethyl-1- (2-pyrrolidone) dithiocarbamate, 2- (ethoxycarbonylbenzyl) prop- -Yl-N, N-diethyldithiocarbamate, 1-phenylethyldithiobenzoate, 2-phenylprop-2-yldithiobenzoate, 1-acetic acid-1-yl-ethyldithiobenzoate, 1- (4-methoxyphenyl) ethyl Dithiobenzoate, benzyldithioacetate, ethoxycarbonylmethyldithioacetate, 2- (ethoxycarbonyl) prop-2-yldithiobenzoate, 2-cyanoprop-2-yldithiobenzoate, t-butyldithiobenzoate, 2,4,4- Trimethylpent-2-yldithiobenzoate, 2- (4-chlorophenyl) -prop-2-yldithiobenzoate, 3-vinylbenzyldithiobenzoate, 4-vinylbenzyldithiobenzoate, benzyldiethoxyphosphinyldi Thioformate, t-butyltrithioperbenzoate, 2-phenylprop-2-yl-4-chlorodithiobenzoate, naphthalene-1-carboxylic acid-1-methyl-1-phenyl-ethyl ester, 4-cyano-4- Methyl-4-thiobenzylsulfanyl butyric acid, dibenzyl tetrathioterephthalate, carboxymethyl dithiobenzoate, poly (ethylene oxide) with dithiobenzoate end groups, 4-cyano-4-methyl-4-thiobenzylsulfanyl butyric acid end group Having poly (ethylene oxide), 2-[(2-phenylethanethioyl) sulfanyl] propanoic acid, 2-[(2-phenylethanethioyl) sulfanyl] succinic acid, 3,5-dimethyl-1H-pyrazole-1 -Potassium carbodithioate, cyanomethyl-3,5 Dimethyl-1H-pyrazole-1-carbodithioate, cyanomethylmethyl- (phenyl) dithiocarbamate, benzyl-4-chlorodithiobenzoate, phenylmethyl-4-chlorodithiobenzoate, 4-nitrobenzyl-4-chlorodithiobenzoate, Phenylprop-2-yl-4-chlorodithiobenzoate, 1-cyano-1-methylethyl-4-chlorodithiobenzoate, 3-chloro-2-butenyl-4-chlorodithiobenzoate, 2-chloro-2-butenyl Dithiobenzoate, benzyl dithioacetate, 3-chloro-2-butenyl-1H-pyrrole-1-dithiocarboxylic acid, 2-cyanobutan-2-yl-4-chloro-3,5-dimethyl-1H-pyrazole-1-carbo Dithioate, cyanomethylmethyl Phenyl) carbamodithioate, 2-cyano-2-propyldodecyltrithiocarbonate, dibenzyltrithiocarbonate, butylbenzyltrithiocarbonate, 2-[[(butylthio) thioxomethyl] thio] propionic acid, 2- [[(Dodecylthio) thioxomethyl] thio] propionic acid, 2-[[(butylthio) thioxomethyl] thio] succinic acid, 2-[[(dodecylthio) thioxomethyl] thio] succinic acid, 2-[[(dodecylthio) thioxomethyl] thio ] -2-Methylpropionic acid, 2,2 ′-[carbonothioylbis (thio)] bis [2-methylpropionic acid], 2-amino-1-methyl-2-oxoethylbutyltrithiocarbonate, benzyl -2-[(2-hydroxyethyl) amino] -1-methyl-2-oxy Thioethyltrithiocarbonate, 3-[[[(t-butyl) thio] thioxomethyl] thio] propionic acid, cyanomethyldodecyltrithiocarbonate, diethylaminobenzyltrithiocarbonate, dibutylaminobenzyltrithiocarbonate, etc. Examples thereof include carbonyl compounds.
　クロロプレン系ゴムの重合温度は、特に限定されるものではなく、一般に乳化重合が行われる温度として、好ましくは０～５０℃であり、より好ましくは２０～５０℃である。前述した重合工程で得られるクロロプレン系ゴムの最終重合率は、特に限定するものではないが、３０～１００％の範囲内で任意に調節することが好ましい。最終転化率を調整するためには、所望する転化率になった時に、重合反応を停止させる重合停止剤を添加して重合を停止させることができる。 The polymerization temperature of the chloroprene rubber is not particularly limited, and is generally 0 to 50 ° C., more preferably 20 to 50 ° C., as the temperature at which emulsion polymerization is performed. The final polymerization rate of the chloroprene rubber obtained in the above-mentioned polymerization step is not particularly limited, but it is preferably adjusted within the range of 30 to 100%. In order to adjust the final conversion, the polymerization can be stopped by adding a polymerization terminator that stops the polymerization reaction when the desired conversion is reached.
　重合停止剤は、特に限定されるものではなく、通常用いられている重合停止剤を使用することができる。重合停止剤の具体例としては、フェノチアジン（チオジフェニルアミン）、４－ターシャリーブチルカテコール、２，２－メチレンビス－４－メチル－６－ターシャリーブチルフェノール等が挙げられる。 The polymerization terminator is not particularly limited, and a commonly used polymerization terminator can be used. Specific examples of the polymerization terminator include phenothiazine (thiodiphenylamine), 4-tert-butylcatechol, and 2,2-methylenebis-4-methyl-6-tert-butylphenol.
　次に、重合工程により得られた重合液から未反応単量体の除去を行う。その方法は、特に限定されるものではなく、例えば、スチームストリッピング法が挙げられる。その後、ｐＨを調整し、常法の凍結凝固、水洗、熱風乾燥等の工程を経てクロロプレン系ゴムを得ることができる。 Next, unreacted monomers are removed from the polymerization liquid obtained in the polymerization process. The method is not particularly limited, and examples thereof include a steam stripping method. Then, the pH is adjusted, and the chloroprene rubber can be obtained through processes such as freeze-coagulation, washing with water, and drying with hot air in a usual manner.
（２）硫黄系化合物
　本実施形態に係るクロロプレンゴム組成物は、下記一般式（１）で表される硫黄系化合物（以下、「特定硫黄系化合物」という）を含有する。特定硫黄系化合物は、得られるクロロプレンゴム組成物の加硫を促進させることができる。
Figure JPOXMLDOC01-appb-C000003
 ［式中、Ｒ１は、水素原子、水酸基又は炭素数１～８のアルキル基を表し、Ｒ２及びＲ３は、それぞれ独立に、水素原子又は炭素数１～８のアルキル基を表す。Ｒ１、Ｒ２及びＲ３のアルキル基の水素原子は、置換基で置換されていてもよい。 (2) Sulfur-based compound The chloroprene rubber composition according to the present embodiment contains a sulfur-based compound represented by the following general formula (1) (hereinafter referred to as "specific sulfur-based compound"). The specific sulfur compound can accelerate vulcanization of the resulting chloroprene rubber composition.
Figure JPOXMLDOC01-appb-C000003
 [In the formula, R 1 represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 8 carbon atoms, and R 2 and R 3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. The hydrogen atom of the alkyl group of R 1 , R 2 and R 3 may be substituted with a substituent.
　特定硫黄系化合物は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、下記の態様の少なくとも一つを満たすことが好ましい。
　Ｒ１は、水素原子又は炭素数１～８のアルキル基が好ましい。
　Ｒ１のアルキル基の炭素数は、好ましくは１～４であり、より好ましくは１～３であり、更に好ましくは１又は２である。
　Ｒ２は、水素原子又は炭素数１～４のアルキル基が好ましく、水素原子又は炭素数１～３のアルキル基がより好ましい。
　Ｒ３は、水素原子が好ましい。 Specific sulfur-based compound, from the viewpoint of easily maintaining a low compression set of the vulcanized molded article, from the viewpoint of easily improving the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging, the following: It is preferable to satisfy at least one of the embodiments.
R 1 is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
The alkyl group of R 1 preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 or 2 carbon atoms.
R 2 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
R 3 is preferably a hydrogen atom.
　特定硫黄系化合物の具体例としては、４－メチルチアゾリジン－２－チオン、３－メチルチアゾリジン－２－チオン、５－メチルチアゾリジン－２－チオン、３，４－ジメチルチアゾリジン－２－チオン、４，５－ジメチルチアゾリジン－２－チオン、３，５－ジメチルチアゾリジン－２－チオン、３，４，５－トリメチルチアゾリジン－２－チオン、４－エチル－３－チアゾリジン－２－チオン、４－イソプロピル－３－チアゾリジン－２－チオン、４－イソプロピル－３－メチルチアゾリジン－２－チオン、４－ヒドロキシチアゾリジン－２－チオン、５－エチル－３－チアゾリジン－２－チオン、５－イソプロピル－３－チアゾリジン－２－チオン、５－イソプロピル－３－メチルチアゾリジン－２－チオン、５－ヒドロキシチアゾリジン－２－チオン、３－エチルチアゾリジン－２－チオン、３－プロピルチアゾリジン－２－チオン、３－ブチルチアゾリジン－２－チオン、３－フェニルチアゾリジン－２－チオン等が挙げられる。特定硫黄系化合物は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、４－メチルチアゾリジン－２－チオン、３－メチルチアゾリジン－２－チオン、及び、４－イソプロピル－３－メチルチアゾリジン－２－チオンから選ばれる少なくとも１種を含むことが好ましい。特定硫黄系化合物は、１種を単独で又は２種以上を組み合わせて用いることができる。 Specific examples of the specific sulfur compound include 4-methylthiazolidine-2-thione, 3-methylthiazolidine-2-thione, 5-methylthiazolidine-2-thione, 3,4-dimethylthiazolidine-2-thione, 4, 5-dimethylthiazolidine-2-thione, 3,5-dimethylthiazolidine-2-thione, 3,4,5-trimethylthiazolidine-2-thione, 4-ethyl-3-thiazolidine-2-thione, 4-isopropyl-3 -Thiazolidine-2-thione, 4-isopropyl-3-methylthiazolidine-2-thione, 4-hydroxythiazolidine-2-thione, 5-ethyl-3-thiazolidine-2-thione, 5-isopropyl-3-thiazolidine-2 -Thion, 5-isopropyl-3-methylthiazolidine-2-thione, 5-hydroxythiazo -2-thione, 3-ethyl-thiazolidine-2-thione, 3-propyl thiazolidine-2-thione, 3-butyl-thiazolidine-2-thione, 3-phenyl-thiazolidine-2-thione, and the like. From the viewpoint of easily maintaining the compression set of the vulcanized molded article at a low level, the viewpoint of easily increasing the vulcanization rate, and the viewpoint of easily suppressing the decrease in elongation at break after heat aging, the specific sulfur compound is 4- It preferably contains at least one selected from methylthiazolidine-2-thione, 3-methylthiazolidine-2-thione, and 4-isopropyl-3-methylthiazolidine-2-thione. The specific sulfur compounds can be used alone or in combination of two or more.
　特定硫黄系化合物の含有量は、クロロプレン系ゴム１００質量部に対して０．５～５．０質量部である。特定硫黄系化合物の含有量が０．５質量部に満たないと、得られるクロロプレンゴム組成物の加硫を促進させる効果が低く、その加硫速度を向上させることができない。また、熱老化後の切断時伸びが低下すると共に圧縮永久ひずみが悪化してしまう場合がある。特定硫黄系化合物の含有量が５．０質量部を超えてしまうと、得られる加硫成形体のゴム弾性が失われて、熱老化後の切断時伸びが低下すると共に圧縮永久ひずみが悪化してしまう場合がある。 The content of the specific sulfur compound is 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the chloroprene rubber. If the content of the specific sulfur compound is less than 0.5 parts by mass, the effect of promoting vulcanization of the obtained chloroprene rubber composition is low and the vulcanization rate cannot be improved. In addition, elongation upon cutting after heat aging may decrease and compression set may deteriorate. If the content of the specific sulfur compound exceeds 5.0 parts by mass, the rubber elasticity of the obtained vulcanized molded article is lost, the elongation at break after heat aging is reduced, and the compression set is deteriorated. It may happen.
　特定硫黄系化合物の含有量は、加硫速度が向上しやすい観点から、好ましくは０．７５質量部以上であり、より好ましくは１．０質量部以上である。特定硫黄系化合物の含有量は、熱老化後の切断時伸びの低下を抑制しやすい観点、及び、加硫成形体の圧縮永久ひずみを低く維持しやすい観点から、好ましくは４．５質量部以下であり、より好ましくは４．０質量部以下であり、更に好ましくは３．５質量部以下であり、特に好ましくは３．０質量部以下であり、極めて好ましくは２．５質量部以下であり、非常に好ましくは２．０質量部以下であり、より一層好ましくは１．５質量部以下であり、更に好ましくは１．０質量部以下である。これらの観点から、特定硫黄系化合物の含有量は、好ましくは０．７５～３．０質量部であり、より好ましくは１．０～２．０質量部である。特定硫黄系化合物の含有量は、加硫速度が更に向上しやすい観点から、好ましくは１．０質量部を超え、より好ましくは１．５質量部以上であり、更に好ましくは２．０質量部以上であり、特に好ましくは２．５質量部以上であり、極めて好ましくは３．０質量部以上であり、非常に好ましくは３．５質量部以上であり、より一層好ましくは４．０質量部以上であり、更に好ましくは４．５質量部以上である。 The content of the specific sulfur compound is preferably 0.75 parts by mass or more, more preferably 1.0 parts by mass or more, from the viewpoint of easily improving the vulcanization rate. The content of the specific sulfur-based compound is preferably 4.5 parts by mass or less, from the viewpoint of easily suppressing a decrease in elongation at break after heat aging, and from the viewpoint of easily keeping the compression set of the vulcanized molded product low. And more preferably 4.0 parts by mass or less, further preferably 3.5 parts by mass or less, particularly preferably 3.0 parts by mass or less, and very preferably 2.5 parts by mass or less. It is very preferably 2.0 parts by mass or less, still more preferably 1.5 parts by mass or less, and further preferably 1.0 parts by mass or less. From these viewpoints, the content of the specific sulfur compound is preferably 0.75 to 3.0 parts by mass, more preferably 1.0 to 2.0 parts by mass. The content of the specific sulfur-based compound is preferably more than 1.0 part by mass, more preferably 1.5 parts by mass or more, and further preferably 2.0 parts by mass, from the viewpoint that the vulcanization rate is more easily improved. Or more, particularly preferably 2.5 parts by mass or more, very preferably 3.0 parts by mass or more, very preferably 3.5 parts by mass or more, and still more preferably 4.0 parts by mass. It is above, and more preferably 4.5 parts by mass or more.
　特定硫黄系化合物の含有量は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、硫黄系化合物の全量（本実施形態に係るクロロプレンゴム組成物に含まれる硫黄系化合物の全量）を基準として、好ましくは８０質量％以上であり、より好ましくは９０質量％以上であり、更に好ましくは９５質量％以上であり、特に好ましくは９８質量％以上であり、極めて好ましくは９９質量％以上である。本実施形態に係るクロロプレンゴム組成物中の硫黄系化合物が実質的に特定硫黄系化合物からなる（硫黄系化合物の実質的に１００質量％が特定硫黄系化合物である）態様であってもよい。 The content of the specific sulfur-based compound, from the viewpoint of easily maintaining a low compression set of the vulcanized molded article, from the viewpoint of easily improving the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. Based on the total amount of the sulfur-based compound (the total amount of the sulfur-based compound contained in the chloroprene rubber composition according to the present embodiment), it is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably Is 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 99% by mass or more. The sulfur-based compound in the chloroprene rubber composition according to the present embodiment may be substantially composed of the specific sulfur-based compound (substantially 100% by mass of the sulfur-based compound is the specific sulfur-based compound).
　本実施形態に係るクロロプレンゴム組成物、特定硫黄系化合物以外の他の硫黄系化合物を含有してよい。このような硫黄系化合物としては、例えば、クロロプレンゴムの加硫に一般に用いられる加硫促進剤を用いることができる。加硫促進剤としては、チオウレア系、グアニジン系、チウラム系、チアゾール系等の加硫促進剤；ジメチルアンモニウムハイドロジェンイソフタレート；１，２－ジメルカプト－１，３，４－チアジアゾール誘導体などが挙げられる。チオウレア系の加硫促進剤としては、エチレンチオウレア、ジエチルチオウレア、トリメチルチオウレア、トリエチルチオウレア、Ｎ，Ｎ’－ジフェニルチオウレア等が挙げられ、トリメチルチオウレア及びエチレンチオウレアから選ばれる少なくとも１種が好ましい。硫黄系化合物は、１種を単独で又は２種以上を組み合わせて用いることができる。 The chloroprene rubber composition according to this embodiment may contain a sulfur-based compound other than the specific sulfur-based compound. As such a sulfur compound, for example, a vulcanization accelerator generally used for vulcanizing chloroprene rubber can be used. Examples of the vulcanization accelerator include thiourea-based, guanidine-based, thiuram-based, thiazole-based vulcanization accelerators; dimethylammonium hydrogen isophthalate; 1,2-dimercapto-1,3,4-thiadiazole derivative and the like. .. Examples of the thiourea-based vulcanization accelerator include ethylenethiourea, diethylthiourea, trimethylthiourea, triethylthiourea, N, N'-diphenylthiourea, and the like, and at least one selected from trimethylthiourea and ethylenethiourea is preferable. The sulfur compounds may be used alone or in combination of two or more.
　硫黄系化合物（本実施形態に係るクロロプレンゴム組成物に含まれる硫黄系化合物の全量）の含有量は、クロロプレン系ゴム１００質量部に対して下記の範囲が好ましい。硫黄系化合物の含有量は、加硫速度が向上しやすい観点から、好ましくは０．５質量部以上であり、より好ましくは０．７５質量部以上であり、更に好ましくは１．０質量部以上である。硫黄系化合物の含有量は、熱老化後の切断時伸びの低下を抑制しやすい観点、及び、加硫成形体の圧縮永久ひずみを低く維持しやすい観点から、好ましくは５．０質量部以下であり、より好ましくは４．５質量部以下であり、更に好ましくは４．０質量部以下であり、特に好ましくは３．５質量部以下であり、極めて好ましくは３．０質量部以下であり、非常に好ましくは２．５質量部以下であり、より一層好ましくは２．０質量部以下であり、更に好ましくは１．５質量部以下であり、特に好ましくは１．０質量部以下である。これらの観点から、硫黄系化合物の含有量は、好ましくは０．５～５．０質量部である。硫黄系化合物の含有量は、加硫速度が更に向上しやすい観点から、好ましくは１．０質量部を超え、より好ましくは１．５質量部以上であり、更に好ましくは２．０質量部以上であり、特に好ましくは２．５質量部以上であり、極めて好ましくは３．０質量部以上であり、非常に好ましくは３．５質量部以上であり、より一層好ましくは４．０質量部以上であり、更に好ましくは４．５質量部以上であり、特に好ましくは５．０質量部以上である。 The content of the sulfur-based compound (the total amount of the sulfur-based compound contained in the chloroprene rubber composition according to this embodiment) is preferably in the following range with respect to 100 parts by mass of the chloroprene rubber. The content of the sulfur-based compound is preferably 0.5 parts by mass or more, more preferably 0.75 parts by mass or more, and further preferably 1.0 parts by mass or more, from the viewpoint of easily improving the vulcanization rate. Is. The content of the sulfur-based compound is preferably 5.0 parts by mass or less from the viewpoint of easily suppressing a decrease in elongation at break after heat aging, and from the viewpoint of easily keeping the compression set of the vulcanized molded product low. Yes, more preferably 4.5 parts by mass or less, further preferably 4.0 parts by mass or less, particularly preferably 3.5 parts by mass or less, and very preferably 3.0 parts by mass or less, It is very preferably 2.5 parts by mass or less, still more preferably 2.0 parts by mass or less, further preferably 1.5 parts by mass or less, and particularly preferably 1.0 parts by mass or less. From these viewpoints, the content of the sulfur-based compound is preferably 0.5 to 5.0 parts by mass. The content of the sulfur-based compound is preferably more than 1.0 part by mass, more preferably 1.5 parts by mass or more, and further preferably 2.0 parts by mass or more, from the viewpoint of further improving the vulcanization rate. And particularly preferably 2.5 parts by mass or more, very preferably 3.0 parts by mass or more, very preferably 3.5 parts by mass or more, and still more preferably 4.0 parts by mass or more. And more preferably 4.5 parts by mass or more, and particularly preferably 5.0 parts by mass or more.
（３）有機過酸化物
　本実施形態に係るクロロプレンゴム組成物は、有機過酸化物を含有する。有機過酸化物は、上述の特定硫黄系化合物との相乗効果により、得られるクロロプレンゴム組成物の加硫を促進させることができる。 (3) Organic peroxide The chloroprene rubber composition according to the present embodiment contains an organic peroxide. The organic peroxide can accelerate the vulcanization of the obtained chloroprene rubber composition by a synergistic effect with the above-mentioned specific sulfur compound.
　有機過酸化物の具体例としては、ジアルキルパーオキサイド、ジアシルパーオキサイド、パーオキシケタール、パーオキシエステル、４，４－ビス［（ｔ－ブチル）ペルオキシ］ペンタン酸ブチル等が挙げられる。有機過酸化物は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、ジアルキルパーオキサイド、パーオキシケタール及び４，４－ビス［（ｔ－ブチル）ペルオキシ］ペンタン酸ブチルから選ばれる少なくとも１種を含むことが好ましい。 Specific examples of the organic peroxide include dialkyl peroxide, diacyl peroxide, peroxyketal, peroxyester, and butyl 4,4-bis [(t-butyl) peroxy] pentanoate. The organic peroxide is a dialkylperoxide from the viewpoint of easily keeping the compression set of the vulcanized molded article low, from the viewpoint of easily increasing the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. It preferably contains at least one selected from oxides, peroxyketals and butyl 4,4-bis [(t-butyl) peroxy] pentanoate.
　ジアルキルパーオキサイドとしては、ジクミルパーオキサイド、２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキサン、２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキシン－３、１，３－ビス（ｔ－ブチルパーオキシイソプロビル）ベンゼン、１，４－ビス（ｔ－ブチルパーオキシイソプロビル）ベンゼン、ｔ－ブチルクミルパーオキサイド、ジ－ｔ－ブチルパーオキサイド等が挙げられる。ジアルキルパーオキサイドは、１種を単独で又は２種以上を組み合わせて用いることができる。 Examples of dialkyl peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne. -3,1,3-bis (t-butylperoxyisoprobyl) benzene, 1,4-bis (t-butylperoxyisoprobyl) benzene, t-butylcumyl peroxide, di-t-butylperoxide, etc. Is mentioned. The dialkyl peroxides can be used alone or in combination of two or more.
　ジアシルパーオキサイドとしては、ジベンゾイルパーオキサイド、ジ－ｐ－メチルベンゾイルパーオキサイド、ジ－ｏ－メチルベンゾイルパーオキサイド等が挙げられる。ジアシルパーオキサイドは、１種を単独で又は２種以上を組み合わせて用いることができる。 Examples of the diacyl peroxide include dibenzoyl peroxide, di-p-methylbenzoyl peroxide, di-o-methylbenzoyl peroxide and the like. The diacyl peroxides can be used alone or in combination of two or more.
　パーオキシケタールとしては、１，１－ジ（ｔ－ヘキシルペロキシ）シクロヘキサン、１，１－ジ（ｔ－ブチルペロキシ）シクロヘキサン、ｎ－ブチル－４，４－ジ（ｔ－ブチルペロキシ）バレラート等が挙げられる。パーオキシケタールは、１種を単独で又は２種以上を組み合わせて用いることができる。 Examples of peroxyketals include 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane, n-butyl-4,4-di (t-butylperoxy) valerate and the like. The peroxyketals may be used alone or in combination of two or more.
　パーオキシエステルとしては、２，５－ジメチル－２，５－ジ（ｔ－ベンゾイルペロキシ）ヘキサン、ｔ－ヘキシルペロキシベンゾエート、ｔ－ブチルペロキシベンゾエート等が挙げられる。パーオキシエステルは、１種を単独で又は２種以上を組み合わせて用いることができる。 Examples of peroxyesters include 2,5-dimethyl-2,5-di (t-benzoylperoxy) hexane, t-hexylperoxybenzoate, t-butylperoxybenzoate and the like. The peroxyesters may be used alone or in combination of two or more.
　有機過酸化物の含有量は、クロロプレン系ゴム１００質量部に対して０質量部を超えて４．０質量部以下である。有機過酸化物の含有量が０質量部であると、得られるクロロプレンゴム組成物の加硫を促進させる効果が低く、その加硫速度を向上させることができない。また、熱老化後の切断時伸びが低下すると共に圧縮永久ひずみが悪化してしまう場合がある。有機過酸化物の含有量が４．０質量部を超えてしまうと、得られる加硫成形体のゴム弾性が失われて、熱老化後の切断時伸びが低下してしまう場合がある。 The content of organic peroxide is more than 0 parts by mass and 4.0 parts by mass or less based on 100 parts by mass of chloroprene rubber. When the content of the organic peroxide is 0 part by mass, the effect of promoting vulcanization of the obtained chloroprene rubber composition is low and the vulcanization rate cannot be improved. In addition, elongation upon cutting after heat aging may decrease and compression set may deteriorate. When the content of the organic peroxide exceeds 4.0 parts by mass, the rubber elasticity of the obtained vulcanized molded product may be lost, and the elongation at break after heat aging may be reduced.
　有機過酸化物の含有量は、加硫成形体の圧縮永久ひずみを低く維持しやすい観点、加硫速度を向上させやすい観点、及び、熱老化後の切断時伸びの低下を抑制しやすい観点から、好ましくは０．０５質量部以上であり、より好ましくは０．０８質量部以上であり、更に好ましくは０．１質量部以上であり、特に好ましくは０．３質量部以上であり、極めて好ましくは０．５質量部以上である。有機過酸化物の含有量は、熱老化後の切断時伸びの低下を抑制しやすい観点から、好ましくは３．０質量部以下であり、より好ましくは２．５質量部以下であり、更に好ましくは２．０質量部以下であり、特に好ましくは１．５質量部以下であり、極めて好ましくは１．０質量部以下である。これらの観点から、有機過酸化物の含有量は、好ましくは０．０５～４．０質量部であり、より好ましくは０．１～３．０質量部であり、更に好ましくは０．１～２．０質量部であり、特に好ましくは０．３～１．０質量部である。有機過酸化物の含有量は、加硫成形体の圧縮永久ひずみを更に低く維持しやすい観点、及び、加硫速度を更に向上させやすい観点から、好ましくは０．７５質量部以上であり、より好ましくは１．０質量部以上であり、更に好ましくは１．５質量部以上であり、特に好ましくは２．０質量部以上であり、極めて好ましくは２．５質量部以上であり、非常に好ましくは３．０質量部以上である。 The content of the organic peroxide is from the viewpoint of easily keeping the compression set of the vulcanized molded article low, from the viewpoint of easily increasing the vulcanization rate, and from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. , Preferably 0.05 parts by mass or more, more preferably 0.08 parts by mass or more, further preferably 0.1 parts by mass or more, particularly preferably 0.3 parts by mass or more, and very preferably Is 0.5 part by mass or more. The content of the organic peroxide is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and further preferably from the viewpoint of easily suppressing a decrease in elongation at break after heat aging. Is 2.0 parts by mass or less, particularly preferably 1.5 parts by mass or less, and very preferably 1.0 parts by mass or less. From these viewpoints, the content of the organic peroxide is preferably 0.05 to 4.0 parts by mass, more preferably 0.1 to 3.0 parts by mass, still more preferably 0.1 to 3.0 parts by mass. The amount is 2.0 parts by mass, and particularly preferably 0.3 to 1.0 part by mass. The content of the organic peroxide is preferably 0.75 parts by mass or more, from the viewpoint of easily maintaining the compression set of the vulcanized molded article even lower and from the viewpoint of further improving the vulcanization rate, and It is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, particularly preferably 2.0 parts by mass or more, very preferably 2.5 parts by mass or more, and very preferably Is 3.0 parts by mass or more.
（４）その他の化合物
　本実施形態に係るクロロプレンゴム組成物は、充填剤又は補強剤；可塑剤；加硫剤；加硫助剤；加工助剤；老化防止剤等を含有してよい。 (4) Other compounds The chloroprene rubber composition according to the present embodiment may contain a filler or a reinforcing agent, a plasticizer, a vulcanizing agent, a vulcanization aid, a processing aid, an antioxidant, and the like.
　充填剤又は補強剤としては、カーボンブラック、シリカ、クレー、タルク、炭酸カルシウム等が挙げられる。充填剤及び補強剤のそれぞれとしては、１種を単独で又は２種以上を組み合わせて用いることができる。充填剤又は補強剤の含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して５～１００質量部が好ましい。 Examples of the filler or reinforcing agent include carbon black, silica, clay, talc, calcium carbonate and the like. Each of the filler and the reinforcing agent may be used alone or in combination of two or more. The content of the filler or the reinforcing agent is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
　可塑剤としては、クロロプレン系ゴムと相溶性を有する可塑剤であれば特に制限はなく、植物油（菜種油等）、フタレート系可塑剤、ＤＯＳ、ＤＯＡ、エステル系可塑剤、エーテル・エステル系可塑剤、チオエーテル系可塑剤、アロマ系オイル、ナフテン系オイルなどが挙げられる。可塑剤は、クロロプレンゴム組成物に要求される特性に合わせて、１種を単独で又は２種以上を組み合わせて用いることができる。可塑剤の含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して５～５０質量部が好ましい。 The plasticizer is not particularly limited as long as it is compatible with chloroprene rubber, vegetable oil (rapeseed oil, etc.), phthalate plasticizer, DOS, DOA, ester plasticizer, ether / ester plasticizer, Examples include thioether plasticizers, aromatic oils, naphthene oils and the like. The plasticizer may be used alone or in combination of two or more, depending on the properties required for the chloroprene rubber composition. The content of the plasticizer is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
　加硫剤としては、特に制限するものではないが金属酸化物が好ましい。金属酸化物の具体例としては、酸化亜鉛、酸化マグネシウム、酸化鉛、四酸化三鉛、三酸化鉄、二酸化チタン、酸化カルシウム、ハイドロタルサイト等が挙げられる。加硫剤は、１種を単独で又は２種以上を組み合わせて用いることができる。加硫剤の含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して３～１５質量部が好ましい。加硫剤を上述の加硫促進剤と併用することにより更に効果的に加硫を行うこともできる。 The vulcanizing agent is not particularly limited, but a metal oxide is preferable. Specific examples of the metal oxide include zinc oxide, magnesium oxide, lead oxide, trilead tetroxide, iron trioxide, titanium dioxide, calcium oxide, hydrotalcite and the like. The vulcanizing agents may be used alone or in combination of two or more. The content of the vulcanizing agent is preferably 3 to 15 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition. Vulcanization can be performed more effectively by using a vulcanizing agent in combination with the above-mentioned vulcanization accelerator.
　本実施形態に係るクロロプレンゴム組成物は、その加硫速度又は加硫密度を向上させる等の観点から、加硫助剤として、二官能性エステル化合物及び三官能性エステル化合物から選ばれる少なくとも１種の化合物を含有することができる。 The chloroprene rubber composition according to the present embodiment, as a vulcanization aid, at least one selected from a difunctional ester compound and a trifunctional ester compound from the viewpoint of improving the vulcanization rate or vulcanization density. Can be included.
　加硫助剤の具体例としては、トリメチロールプロパン、エチレングリコールジメタクリレート、トリアリルイソシアネート、トリアリルシアネート、マレイミド系化合物等が挙げられる。加硫助剤は、１種を単独で又は２種以上を組み合わせて用いることができる。 Specific examples of the vulcanization aid include trimethylolpropane, ethylene glycol dimethacrylate, triallyl isocyanate, triallyl cyanate, and maleimide compounds. The vulcanization aids may be used alone or in combination of two or more.
　マレイミド系化合物としては、Ｎ－シクロヘキシルマレイミド、Ｎ－メチルマレイミド、Ｎ－エチルマレイミド、Ｎ－イソプロピルマレイミド、Ｎ－ｎ－ブチルマレイミド、２－メチル－Ｎ－フェニルマレイミド、２，３－ジメチルマレイミド、２－エチルマレイミド、２－ｎ－ブチルマレイミド、Ｎ－ベンジルマレイミド、Ｎ，Ｎ’－１，２－エチルビスマレイミド、Ｎ，Ｎ’－１，２－ヘキシルビスマレイミド、Ｎ－プロピオン酸マレイミド、４，４’－ビスマレイミドジフェニルメタン、６，７－メチレンジオキシ－４－メチル－３－クマル酸マレイミド、ビス（３－エチル－５－メチル－４－マレイミドフェニル）メタン、Ｎ－ブロモメチル－２，３－ジクロロマレイミド、Ｎ－（３－マレイミドベンゾイルオキシ）コハク酸、Ｎ－（３－マレイミドプロピオオキシ）コハク酸、Ｎ－（３－マレイミドブチルオキシ）コハク酸、Ｎ－（３－マレイミドヘキシルオキシ）コハク酸、Ｎ－（４－ジメチルアミノ－３，５－ジニトロフェニル）マレイミド、Ｎ，Ｎ’－１，２－フェニレンジマレイミド、Ｎ，Ｎ’－１，３－フェニレンジマレイミド、Ｎ，Ｎ’－１，４－フェニレンジマレイミド、Ｎ－Ｎ’－１，３－ナフテンジマレイミド、Ｎ，Ｎ’－（４－メチル－１，３－フェニレン）ビスマレイミド、Ｎ－（１－ピレニル）マレイミド、１，１’－（メチレンジ－４，１－フェニレン）ビスマレイミド、Ｎ－［４－（２－ベンズイミダゾリル）フェニル］マレイミド、Ｎ－（９－アクリジニル）マレイミド、Ｎ－ヒドロキシマレイミド、２，３－ジフェニルマレイミド等が挙げられる。 Examples of maleimide compounds include N-cyclohexylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, 2-methyl-N-phenylmaleimide, 2,3-dimethylmaleimide, 2 -Ethyl maleimide, 2-n-butyl maleimide, N-benzyl maleimide, N, N'-1,2-ethyl bismaleimide, N, N'-1,2-hexyl bismaleimide, N-propionic acid maleimide, 4, 4'-bismaleimidodiphenylmethane, 6,7-methylenedioxy-4-methyl-3-coumaric acid maleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, N-bromomethyl-2,3- Dichloromaleimide, N- (3-maleimidobenzoyloxy) succinic acid, N (3-maleimidopropiooxy) succinic acid, N- (3-maleimidobutyloxy) succinic acid, N- (3-maleimidohexyloxy) succinic acid, N- (4-dimethylamino-3,5-dinitrophenyl) Maleimide, N, N'-1,2-phenylenedimaleimide, N, N'-1,3-phenylenedimaleimide, N, N'-1,4-phenylenedimaleimide, NN'-1,3- Naphthene dimaleimide, N, N '-(4-methyl-1,3-phenylene) bismaleimide, N- (1-pyrenyl) maleimide, 1,1'-(methylenedi-4,1-phenylene) bismaleimide, N -[4- (2-benzimidazolyl) phenyl] maleimide, N- (9-acridinyl) maleimide, N-hydroxymaleimide, 2,3-diphenylmaleimide, etc. And the like.
　加硫助剤の含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して下記の範囲が好ましい。加硫助剤の含有量は、加硫助剤を添加する効果を充分に得やすい観点から、好ましくは０．２質量部以上であり、より好ましくは０．５質量部以上である。加硫助剤の含有量は、得られる加硫物の硬度が過剰に高くなることを抑制しやすい観点から、好ましくは５質量部以下であり、より好ましくは４質量部以下である。これらの観点から、加硫助剤の含有量は、好ましくは０．２～５質量部であり、より好ましくは０．５～４質量部である。 The content of the vulcanization aid is preferably in the following range with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition. The content of the vulcanization aid is preferably 0.2 parts by mass or more, and more preferably 0.5 parts by mass or more, from the viewpoint of easily obtaining the effect of adding the vulcanization aid. The content of the vulcanization aid is preferably 5 parts by mass or less, and more preferably 4 parts by mass or less, from the viewpoint of easily suppressing the hardness of the obtained vulcanized product from becoming excessively high. From these viewpoints, the content of the vulcanization aid is preferably 0.2 to 5 parts by mass, more preferably 0.5 to 4 parts by mass.
　加工助剤としては、ステアリン酸等の脂肪酸；ポリエチレン等のパラフィン系加工助剤；脂肪酸アミドなどが挙げられる。加工助剤は、１種を単独で又は２種以上を組み合わせて用いることができる。加工助剤の含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して０．５～５質量部が好ましい。 Examples of processing aids include fatty acids such as stearic acid; paraffin-based processing aids such as polyethylene; fatty acid amides. The processing aids may be used alone or in combination of two or more. The content of the processing aid is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition.
　老化防止剤としては、アミン系老化防止剤、イミダゾール系老化防止剤、カルバミン酸金属塩、フェノール系老化防止剤、ワックス、耐オゾン老化防止剤（例えばＮ－フェニル－Ｎ’－（１，３－ジメチルブチル）－ｐ－フェニレンジアミン）等が挙げられる。老化防止剤は、耐熱性の改良効果が大きい観点から、アミン系老化防止剤が好ましく、４，４’－ビス（α，α－ジメチルベンジル）ジフェニルアミン、及び、オクチル化ジフェニルアミンから選ばれる少なくとも１種がより好ましく、４，４’－ビス（α，α－ジメチルベンジル）ジフェニルアミンが更に好ましい。老化防止剤は、１種を単独で又は２種以上を組み合わせて用いることができる。 As the antiaging agent, an amine antiaging agent, an imidazole antiaging agent, a carbamate metal salt, a phenol antiaging agent, a wax, an ozone antiaging agent (for example, N-phenyl-N '-(1,3- Dimethylbutyl) -p-phenylenediamine) and the like. The anti-aging agent is preferably an amine-based anti-aging agent from the viewpoint of a large effect of improving heat resistance, and at least one selected from 4,4′-bis (α, α-dimethylbenzyl) diphenylamine and octylated diphenylamine. Is more preferable, and 4,4′-bis (α, α-dimethylbenzyl) diphenylamine is even more preferable. The antioxidants can be used alone or in combination of two or more.
　本実施形態に係るクロロプレンゴム組成物は、クロロプレンゴム組成物の加工安定性を向上させる等の観点から、フェノチアジンを含有することもできる。 The chloroprene rubber composition according to the present embodiment may contain phenothiazine from the viewpoint of improving the processing stability of the chloroprene rubber composition.
　フェノチアジンの含有量は、クロロプレン系ゴム１００質量部又はクロロプレンゴム組成物１００質量部に対して、好ましくは０．１～２質量部であり、より好ましくは０．３～１．５質量部である。これらの範囲でフェノチアジンを用いることにより、得られるクロロプレンゴム組成物の加工安定性を向上させる効果が高い。 The content of phenothiazine is preferably 0.1 to 2 parts by mass, more preferably 0.3 to 1.5 parts by mass based on 100 parts by mass of the chloroprene rubber or 100 parts by mass of the chloroprene rubber composition. .. By using phenothiazine in these ranges, the effect of improving the processing stability of the obtained chloroprene rubber composition is high.
　本実施形態に係るクロロプレンゴム組成物は、上述の化合物をその加硫温度以下の温度で混練することで得ることができる。混練装置としては、ミキサー、バンバリーミキサー、ニーダーミキサー、二本ロール等を用いることができる。 The chloroprene rubber composition according to the present embodiment can be obtained by kneading the above compound at a temperature below its vulcanization temperature. As the kneading device, a mixer, a Banbury mixer, a kneader mixer, a two-roll mill or the like can be used.
＜成形体及び加硫成形体＞
　本実施形態に係る成形体は、本実施形態に係るクロロプレンゴム組成物の成形体であり、本実施形態に係るクロロプレンゴム組成物を成形して得ることができる。本実施形態に係る加硫成形体は、本実施形態に係るクロロプレンゴム組成物の加硫成形体である。本実施形態に係る加硫成形体は、本実施形態に係るクロロプレンゴム組成物を、所望する各種の形状に成形した後に加硫したり、本実施形態に係るクロロプレンゴム組成物を加硫した後に各種の形状に成形したりして得ることができる。クロロプレンゴム組成物から加硫成形体を成形する方法は、プレス成形、押出成形、カレンダー成形等の方法を用いることができる。 <Molded product and vulcanized molded product>
The molded body according to this embodiment is a molded body of the chloroprene rubber composition according to this embodiment, and can be obtained by molding the chloroprene rubber composition according to this embodiment. The vulcanized molded product according to the present embodiment is a vulcanized molded product of the chloroprene rubber composition according to the present embodiment. The vulcanized molded article according to the present embodiment, the chloroprene rubber composition according to the present embodiment, vulcanized after molding into various desired shapes, or after vulcanizing the chloroprene rubber composition according to the present embodiment. It can be obtained by molding into various shapes. As a method for molding a vulcanized molded body from the chloroprene rubber composition, a method such as press molding, extrusion molding or calender molding can be used.
　クロロプレンゴム組成物を加硫する温度は、その組成に合わせて適宜設定すればよく、好ましくは１４０～２２０℃であり、より好ましくは１５０～１８０℃である。加硫する時間も、クロロプレンゴム組成物の組成又は形状によって適宜設定すればよく、１０～６０分であってよい。 The temperature for vulcanizing the chloroprene rubber composition may be set appropriately according to the composition, and is preferably 140 to 220 ° C, more preferably 150 to 180 ° C. The vulcanization time may also be appropriately set depending on the composition or shape of the chloroprene rubber composition, and may be 10 to 60 minutes.
　本実施形態に係る加硫成形体は、本実施形態に係るクロロプレンゴム組成物を加硫成形して得られるものであり、加硫速度を速いにもかかわらず、その圧縮永久ひずみが維持されると共に熱老化後の切断時伸びの低下が抑制されたものである。 The vulcanized molded article according to the present embodiment is obtained by vulcanizing and molding the chloroprene rubber composition according to the present embodiment, and its compression set is maintained despite the high vulcanization rate. At the same time, the decrease in elongation at break after heat aging was suppressed.
　以下、実施例に基づいて本発明を更に詳細に説明する。なお、以下に説明する実施例は、本発明の代表的な実施例の一例を示したものであり、これにより本発明の範囲が狭く解釈されることはない。 Hereinafter, the present invention will be described in more detail based on examples. The embodiments described below are examples of typical embodiments of the present invention, and the scope of the present invention should not be construed narrowly.
＜クロロプレン－アクリロニトリル共重合ゴムの製造＞
　加熱冷却ジャケット及び攪拌機を備えた内容積３リットルの重合缶に、クロロプレン単量体３７質量部、アクリロニトリル単量体４質量部、ジエチルキサントゲンジスルフィド０．５質量部、純水２００質量部、ロジン酸カリウム（ハリマ化成株式会社製）５．００質量部、水酸化ナトリウム０．４０質量部、及び、β－ナフタレンスルホン酸ホルマリン縮合物のナトリウム塩（花王株式会社製）２．０質量部を添加した。次に、重合開始剤として過硫酸カリウム０．１質量部を添加した後、重合温度４０℃にて窒素気流下で乳化重合を行った。クロロプレン単量体の分添は、重合開始２０秒後から開始し、重合開始からの１０秒間の冷媒の熱量変化を元に分添流量を電磁弁で調整し、以降１０秒毎に流量を再調節することで連続的に行った。クロロプレン単量体及びアクリロニトリル単量体の合計量に対する重合率が５０％となった時点で、重合停止剤であるフェノチアジンを加えて重合を停止させた。その後、減圧下で反応溶液中の未反応単量体を除去することでクロロプレン－アクリロニトリル共重合体ラテックスを得た。 <Production of chloroprene-acrylonitrile copolymer rubber>
In a polymerization vessel having an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer, 37 parts by mass of chloroprene monomer, 4 parts by mass of acrylonitrile monomer, 0.5 part by mass of diethylxanthogen disulfide, 200 parts by mass of pure water, rosin acid 5.00 parts by mass of potassium (manufactured by Harima Kasei Co., Ltd.), 0.40 part by mass of sodium hydroxide, and 2.0 parts by mass of sodium salt of β-naphthalenesulfonic acid formalin condensate (manufactured by Kao Co., Ltd.) were added. .. Next, 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and then emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. The addition of the chloroprene monomer started 20 seconds after the start of the polymerization, and the addition flow rate was adjusted with a solenoid valve based on the change in the amount of heat of the refrigerant for 10 seconds after the start of the polymerization. It was performed continuously by adjusting. When the polymerization rate with respect to the total amount of the chloroprene monomer and the acrylonitrile monomer reached 50%, phenothiazine as a polymerization terminator was added to terminate the polymerization. Then, the unreacted monomer in the reaction solution was removed under reduced pressure to obtain a chloroprene-acrylonitrile copolymer latex.
　クロロプレン－アクリロニトリル共重合体ラテックスの重合率は、クロロプレン－アクリロニトリル共重合体ラテックスを風乾した乾燥質量から算出した。具体的には、下記式（Ｉ）より計算した。式中、固形分濃度とは、サンプリングしたクロロプレン－アクリロニトリル共重合体ラテックス２ｇを１３０℃で加熱して、溶媒（水）、揮発性薬品、原料等の揮発成分を除いた固形分の濃度［質量％］である。総仕込み量とは、重合開始から、ある時刻までに重合缶に仕込んだ原料、試薬及び溶媒（水）の総量である。蒸発残分とは、重合開始から、ある時刻までに仕込んだ薬品及び原料のうち、１３０℃の条件下で揮発せずにポリマーと共に固形分として残留する薬品の質量である。単量体仕込み量は、重合缶に初期に仕込んだ単量体、及び、重合開始から、ある時刻までに分添した単量体の量の合計である。なお、ここでいう「単量体」とはクロロプレン単量体とアクリロニトリル単量体の合計量である。
　重合率［％］＝｛（総仕込み量［ｇ］×固形分濃度［質量％］／１００）－（蒸発残分［ｇ］）｝／単量体仕込み量［ｇ］×１００　　　・・・（Ｉ） The polymerization rate of the chloroprene-acrylonitrile copolymer latex was calculated from the dry mass of the chloroprene-acrylonitrile copolymer latex air-dried. Specifically, it was calculated by the following formula (I). In the formula, the solid content concentration means the concentration of solid content obtained by heating 2 g of sampled chloroprene-acrylonitrile copolymer latex at 130 ° C. and removing volatile components such as solvent (water), volatile chemicals and raw materials [mass %]. The total amount charged is the total amount of raw materials, reagents and solvent (water) charged in a polymerization vessel from the start of polymerization to a certain time. The evaporation residue is the mass of the chemicals and raw materials charged from the start of the polymerization to a certain time and remaining as a solid content together with the polymer without being volatilized under the condition of 130 ° C. The monomer charging amount is the total of the amount of the monomer initially charged in the polymerization vessel and the amount of the monomer added by a certain time from the start of polymerization. The "monomer" referred to here is the total amount of the chloroprene monomer and the acrylonitrile monomer.
Polymerization rate [%] = {(total charged amount [g] × solid content concentration [mass%] / 100) − (evaporation residue [g])} / monomer charged amount [g] × 100 ( I)
　上述のクロロプレン－アクリロニトリル共重合体ラテックスをｐＨ７．０に調整し、－２０℃に冷やした金属板上で凍結凝固させることで乳化破壊することによりシートを得た。このシートを水洗した後、１３０℃で１５分間乾燥させることにより固形状のクロロプレン－アクリロニトリル共重合ゴムを得た。 A sheet was obtained by adjusting the pH of the above-mentioned chloroprene-acrylonitrile copolymer latex to pH 7.0 and freeze-coagulating it on a metal plate cooled to -20 ° C to break the emulsion. The sheet was washed with water and then dried at 130 ° C. for 15 minutes to obtain a solid chloroprene-acrylonitrile copolymer rubber.
　クロロプレン－アクリロニトリル共重合ゴムの数平均分子量（Ｍｎ）、重量平均分子量（Ｍｗ）及び分子量分布（Ｍｗ／Ｍｎ）は、クロロプレン－アクリロニトリル共重合ゴムをＴＨＦでサンプル調整濃度０．１質量％の溶液とした後、高速ＧＰＣ装置（ＴＯＳＯＨ　ＨＬＣ－８３２０ＧＰＣ：東ソー株式会社製）により測定した（標準ポリスチレン換算）。その際、プレカラムとしてＴＳＫガードカラムＨＨＲ－Ｈを使用し、分析カラムとしてＨＳＫｇｅｌＧＭＨＨＲ－Ｈ３本を使用し、サンプルポンプ圧８．０～９．５ＭＰａ、流量１ｍｌ／ｍｉｎ、４０℃で流出させ、示差屈折計で検出した。 The number-average molecular weight (Mn), weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the chloroprene-acrylonitrile copolymer rubber are the same as those of the chloroprene-acrylonitrile copolymer rubber in a sample adjusted concentration of 0.1 mass% with THF. After that, it was measured by a high-speed GPC device (TOSOH HLC-8320GPC: manufactured by Tosoh Corporation) (standard polystyrene conversion). At that time, the TSK guard column HHR-H was used as a pre-column, three HSKgel GMHHR-H were used as an analytical column, and the sample pump pressure was 8.0 to 9.5 MPa, the flow rate was 1 ml / min, and the flow rate was 40 ° C. It was detected by the total.
　流出時間と分子量は、以下に挙げる分子量既知の標準ポリスチレンサンプル計９点を測定して作成した校正曲線を用いて得た。
　Ｍｗ＝８．４２×１０６、１．０９×１０６、７．０６×１０５、４．２７×１０５、１．９０×１０５、９．６４×１０４、３．７９×１０４、１．７４×１０４、２．６３×１０３ The outflow time and the molecular weight were obtained using a calibration curve prepared by measuring 9 points of standard polystyrene samples with known molecular weights as shown below.
Mw = 8.42 × 10 6 , 1.09 × 10 6 , 7.06 × 10 5 , 4.27 × 10 5 , 1.90 × 10 5 , 9.64 × 10 4 , 3.79 × 10 4. 1,74 × 10 4 , 2.63 × 10 3
　クロロプレン－アクリロニトリル共重合ゴムに含まれる不飽和ニトリル単量体由来の構造単位量は、クロロプレン－アクリロニトリル共重合ゴム中の窒素原子の含有量から算出した。具体的には、元素分析装置（スミグラフ２２０Ｆ：株式会社住化分析センター製）を用いて１００ｍｇのクロロプレン－アクリロニトリル共重合ゴムの窒素原子の含有量を測定し、アクリロニトリル単量体由来の構造単位を算出した。元素分析の測定は次の条件で行った。電気炉温度として反応炉９００℃、還元炉６００℃、カラム温度７０℃、検出器温度１００℃に設定し、燃焼用ガスとして酸素を０．２ｍｌ／ｍｉｎ、キャリアーガスとしてヘリウムを８０ｍｌ／ｍｉｎフローした。検量線は、窒素含有量が既知のアスパラギン酸（１０．５２％）を標準物質に用いて作成した。 The amount of structural units derived from the unsaturated nitrile monomer contained in the chloroprene-acrylonitrile copolymer rubber was calculated from the content of nitrogen atoms in the chloroprene-acrylonitrile copolymer rubber. Specifically, the nitrogen atom content of 100 mg of chloroprene-acrylonitrile copolymer rubber was measured using an elemental analyzer (Sumigraph 220F: manufactured by Sumika Analytical Center Co., Ltd.), and the structural unit derived from the acrylonitrile monomer was measured. Calculated. The elemental analysis was performed under the following conditions. The electric furnace temperature was set to 900 ° C. for the reaction furnace, 600 ° C. for the reduction furnace, 70 ° C. for the column temperature, and 100 ° C. for the detector temperature. .. The calibration curve was prepared using aspartic acid (10.52%) with a known nitrogen content as a standard substance.
　クロロプレン－アクリロニトリル共重合ゴムの数平均分子量（Ｍｎ）は１３８×１０３／ｍｏｌ、重量平均分子量（Ｍｗ）は４７３×１０３ｇ／ｍｏｌ、分子量分布（Ｍｗ／Ｍｎ）は３．４であった。また、クロロプレン－アクリロニトリル共重合ゴム中のアクリロニトリル単量体由来の構造単位量は１．２質量％であった。 The chloroprene-acrylonitrile copolymer rubber had a number average molecular weight (Mn) of 138 × 10 3 / mol, a weight average molecular weight (Mw) of 473 × 10 3 g / mol, and a molecular weight distribution (Mw / Mn) of 3.4. .. The amount of structural units derived from the acrylonitrile monomer in the chloroprene-acrylonitrile copolymer rubber was 1.2% by mass.
＜クロロプレンゴム組成物の製造＞
　上述のクロロプレン－アクリロニトリル共重合ゴム（クロロプレン－アクリロニトリル共重合体）又はクロロプレンゴム（デンカ株式会社製、メルカプタン変性クロロプレンゴム、生ゴムムーニー粘度ＭＬ１＋４（１００℃）＝６０）１００質量部と、表１に示す硫黄系化合物と、表１に示す有機過酸化物と、ステアリン酸（新日本理化株式会社製、ステアリン酸５０Ｓ）０．５質量部と、カーボンブラック（東海カーボン株式会社製、シーストＳＯ、ＦＥＦカーボン）５０質量部と、可塑剤（大八化学工業株式会社製、ジオクチルセバケート）１０質量部と、酸化マグネシウム（協和化学工業株式会社製、キョーワマグ（登録商標）１５０）４質量部と、耐熱老化防止剤（大内新興化学工業株式会社製、ノクラック（登録商標）ＣＤ、４，４’－ビス（α，α－ジメチルベンジル）ジフェニルアミン）３質量部と、酸化亜鉛（堺化学工業株式会社製、酸化亜鉛２種）５質量部と、耐オゾン老化防止剤（大内新興化学工業株式会社製、ノクラック（登録商標）６Ｃ、Ｎ－フェニル－Ｎ’－（１，３－ジメチルブチル）－ｐ－フェニレンジアミン）１質量部とを８インチオープンロールにおいて混練することによりクロロプレンゴム組成物を得た。表中、「ｐｈｒ」は「質量部」を意味する。 <Production of chloroprene rubber composition>
100 parts by mass of the above-mentioned chloroprene-acrylonitrile copolymer rubber (chloroprene-acrylonitrile copolymer) or chloroprene rubber (Denka Corporation, mercaptan-modified chloroprene rubber, raw rubber Mooney viscosity ML 1 + 4 (100 ° C.) = 60), and Table 1 Sulfur compounds shown, organic peroxides shown in Table 1, 0.5 parts by mass of stearic acid (Shin Nippon Rika Co., Ltd., stearic acid 50S), carbon black (Tokai Carbon Co., Ltd., Seast SO, FEF) Carbon) 50 parts by mass, plasticizer (manufactured by Daihachi Chemical Industry Co., Ltd., dioctyl sebacate) 10 parts by mass, magnesium oxide (Kyowa Chemical Industry Co., Ltd., Kyowamag (registered trademark) 150) 4 parts by mass, heat resistance Anti-aging agent (Ouchi Shinko Chemical Co., Ltd., Nocrac (registered trademark) CD, 4 3 parts by mass of 4'-bis (α, α-dimethylbenzyl) diphenylamine), 5 parts by mass of zinc oxide (2 kinds of zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.), and an anti-aging agent for ozone (Ouchi Shinko Chemical Co., Ltd.) Chloroprene rubber composition by kneading Nocrac (registered trademark) 6C, 1 part by mass of N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine) manufactured by Co., Ltd. in an 8-inch open roll Got In the table, "phr" means "part by mass".
　表１に示す硫黄系化合物及び有機過酸化物は以下のとおりである。
　硫黄系化合物Ａ：３－メチルチアゾリジン－２－チオン、ランクセス社製、レノグランＭＴＴ－８０
　硫黄系化合物Ｂ：４－メチルチアゾリジン－２－チオン（市販品）
　硫黄系化合物Ｃ：４－イソプロピル－３－メチルチアゾリジン－２－チオン（市販品）
　有機過酸化物Ａ：日本油脂株式会社製、パーブチル（登録商標）Ｐ－４０
　有機過酸化物Ｂ：日本油脂株式会社製、パーブチル（登録商標）Ｃ－４０
　有機過酸化物Ｃ：日本油脂株式会社製、パーヘキサ（登録商標）２５Ｂ The sulfur compounds and organic peroxides shown in Table 1 are as follows.
Sulfur-based compound A: 3-methylthiazolidine-2-thione, manufactured by LANXESS, Renoglan MTT-80
Sulfur-based compound B: 4-methylthiazolidine-2-thione (commercially available product)
Sulfur-based compound C: 4-isopropyl-3-methylthiazolidine-2-thione (commercially available product)
Organic peroxide A: Perbutyl (registered trademark) P-40 manufactured by NOF CORPORATION
Organic peroxide B: Perbutyl (registered trademark) C-40 manufactured by NOF CORPORATION
Organic peroxide C: Perhexa (registered trademark) 25B manufactured by NOF CORPORATION
＜クロロプレンゴム組成物の加硫速度の評価＞
　上述のクロロプレンゴム組成物について、日本ゴム協会標準規格ＳＲＩＳ３１０２－１９７７に準拠して、オシレーションディスクレオメータ（Ｎｏ．２９２ロータスレオメータ、株式会社東洋精機製作所製）を用いて１７０℃×３０分における加硫時間（Ｔ９０及びＴ１０）を測定し、加硫速度（Ｔ９０－Ｔ１０）を算出した。加硫速度が１５分以下の値である場合を合格と評価した。 <Evaluation of Vulcanization Rate of Chloroprene Rubber Composition>
The above chloroprene rubber composition was vulcanized at 170 ° C. for 30 minutes using an oscillation disk rheometer (No. 292 Lotus Rheometer, manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with the Japan Rubber Association standard SRIS3102-1977. The time (T90 and T10) was measured, and the vulcanization rate (T90-T10) was calculated. The case where the vulcanization rate was 15 minutes or less was evaluated as acceptable.
＜加硫成形体の製造＞
　上述のクロロプレンゴム組成物を１７０℃×２０分の条件でプレス加硫して厚さ２ｍｍのシート状の加硫成形体を作製した。 <Manufacture of vulcanized molded body>
The above chloroprene rubber composition was press-vulcanized under the conditions of 170 ° C. for 20 minutes to prepare a sheet-shaped vulcanized molded product having a thickness of 2 mm.
＜加硫成形体の評価＞
　上述の加硫成形体について以下の評価を行った。評価結果を表１に示す。 <Evaluation of vulcanized molded body>
The following evaluation was performed on the above-mentioned vulcanized molded body. The evaluation results are shown in Table 1.
（１）熱老化後の切断時伸びの変化率
　ＪＩＳ　Ｋ６２５１に準拠して、シート状の加硫成形体を厚さ２ｍｍのダンベル状３号形試験片に成形した測定サンプルを１０枚準備した。株式会社島津製作所製の加硫ゴム用長ストローク引張試験システムを用いて、１０枚の測定サンプルのうちの５枚の測定サンプルの切断時伸びを引張速度５００ｍｍ／分で測定した。次いで、残りの５枚の測定サンプルを１３０℃で７２時間熱処理した後、切断時伸びを上述の方法と同一の方法で測定した。熱処理前後の値の変化率（低下率）を下記式（ＩＩ）によって算出した。式中、Ａは熱処理前の測定サンプルの切断時伸びの値（５枚の平均値）を示し、Ｂは熱処理後の測定サンプルの切断時伸びの値（５枚の平均値）を示す。変化率が－１５％以上０％以下の値である場合を合格であると評価した。
　熱老化後の切断時伸びの変化率（％）＝（Ｂ－Ａ）／Ａ×１００　・・・（ＩＩ） (1) Change rate of elongation at break after heat aging In accordance with JIS K6251, a sheet-shaped vulcanized molded body was molded into a dumbbell-shaped No. 3 test piece having a thickness of 2 mm to prepare 10 measurement samples. Using a long stroke tensile test system for vulcanized rubber manufactured by Shimadzu Corporation, the elongation at break of 5 of the 10 measurement samples was measured at a tensile speed of 500 mm / min. Next, the remaining five measurement samples were heat-treated at 130 ° C. for 72 hours, and then the elongation at break was measured by the same method as described above. The change rate (decrease rate) of the values before and after the heat treatment was calculated by the following formula (II). In the formula, A represents the elongation value at break (average value of 5 sheets) of the measurement sample before heat treatment, and B represents the elongation value at break (average value of 5 sheets) of the measurement sample after heat treatment. The case where the rate of change was between -15% and 0% was evaluated as acceptable.
Change rate of elongation at break after heat aging (%) = (BA) / A × 100 (II)
（２）圧縮永久ひずみ
　ＪＩＳ　Ｋ６２６２に基づいて、１３０℃、７２時間における圧縮永久ひずみの評価を行った。圧縮永久ひずみが５４％以下の値である場合を合格であると評価した。 (2) Compression set The compression set at 130 ° C. for 72 hours was evaluated based on JIS K6262. The case where the compression set was 54% or less was evaluated as acceptable.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表１に示した結果から、実施例のクロロプレンゴム組成物を用いて加硫成形体を得た際に、圧縮永久ひずみを維持すると共に熱老化後の切断時伸びの低下を抑制しつつ加硫速度が向上していることがわかった。当該加硫成形体は、これらの性質を有するため、生産性に優れ、自動車用ゴム部材（シール材等）、ホース（ホース材）、ゴム型物、ガスケットなどの成形品として好適に使用できる。 From the results shown in Table 1, when vulcanized molded articles were obtained using the chloroprene rubber compositions of Examples, vulcanization was performed while maintaining compression set and suppressing the decrease in elongation at break after heat aging. It turns out that the speed is improving. Since the vulcanized molded product has these properties, it is excellent in productivity and can be suitably used as a molded product such as a rubber member for automobile (sealing material), a hose (hose material), a rubber mold, a gasket and the like.

Claims (5)

  1. 　クロロプレン系ゴム１００質量部と、下記一般式（１）で表される硫黄系化合物０．５～５．０質量部と、有機過酸化物０質量部を超えて４．０質量部以下と、を含有する、クロロプレンゴム組成物。
    Figure JPOXMLDOC01-appb-C000001
     ［式中、Ｒ１は、水素原子、水酸基又は炭素数１～８のアルキル基を表し、Ｒ２及びＲ３は、それぞれ独立に、水素原子又は炭素数１～８のアルキル基を表す。］     100 parts by mass of chloroprene rubber, 0.5 to 5.0 parts by mass of a sulfur compound represented by the following general formula (1), and more than 0 parts by mass and 4.0 parts by mass or less of an organic peroxide: A chloroprene rubber composition containing:
    Figure JPOXMLDOC01-appb-C000001
     [In the formula, R 1 represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 8 carbon atoms, and R 2 and R 3 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ]
  2. 　前記硫黄系化合物が、４－メチルチアゾリジン－２－チオン、３－メチルチアゾリジン－２－チオン、及び、４－イソプロピル－３－メチルチアゾリジン－２－チオンから選ばれる少なくとも１種を含む、請求項１に記載のクロロプレンゴム組成物。 2. The sulfur-based compound contains at least one selected from 4-methylthiazolidine-2-thione, 3-methylthiazolidine-2-thione, and 4-isopropyl-3-methylthiazolidine-2-thione. The chloroprene rubber composition according to.
  3. 　前記有機過酸化物が、ジアルキルパーオキサイド、パーオキシケタール及び４，４－ビス［（ｔ－ブチル）ペルオキシ］ペンタン酸ブチルから選ばれる少なくとも１種を含む、請求項１又は２に記載のクロロプレンゴム組成物。 The chloroprene rubber according to claim 1, wherein the organic peroxide contains at least one selected from dialkyl peroxide, peroxyketal and butyl 4,4-bis [(t-butyl) peroxy] pentanoate. Composition.
  4. 　前記クロロプレン系ゴムが、２－クロロ－１，３－ブタジエンの単独重合体、及び、２－クロロ－１，３－ブタジエンの共重合体から選ばれる少なくとも１種を含み、
    　前記２－クロロ－１，３－ブタジエンの共重合体が、２－クロロ－１，３－ブタジエンと、２，３－ジクロロ－１，３－ブタジエン及びアクリロニトリルから選ばれる少なくとも１種の単量体との共重合体を含む、請求項１～３のいずれか一項に記載のクロロプレンゴム組成物。     The chloroprene rubber contains at least one selected from a homopolymer of 2-chloro-1,3-butadiene and a copolymer of 2-chloro-1,3-butadiene,
    The 2-chloro-1,3-butadiene copolymer is 2-chloro-1,3-butadiene, and at least one monomer selected from 2,3-dichloro-1,3-butadiene and acrylonitrile. The chloroprene rubber composition according to any one of claims 1 to 3, which comprises a copolymer with
  5. 　請求項１～４のいずれか一項に記載のクロロプレンゴム組成物の加硫成形体。 A vulcanized molded product of the chloroprene rubber composition according to any one of claims 1 to 4.
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