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WO2024203715A1 - Latex copolymère de chloroprène-nitrile insaturé, composant en caoutchouc, composition de caoutchouc, moulage vulcanisé et procédé de production d'un latex copolymère chloroprène-nitrile insaturé - Google Patents

Latex copolymère de chloroprène-nitrile insaturé, composant en caoutchouc, composition de caoutchouc, moulage vulcanisé et procédé de production d'un latex copolymère chloroprène-nitrile insaturé Download PDF

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Publication number
WO2024203715A1
WO2024203715A1 PCT/JP2024/011008 JP2024011008W WO2024203715A1 WO 2024203715 A1 WO2024203715 A1 WO 2024203715A1 JP 2024011008 W JP2024011008 W JP 2024011008W WO 2024203715 A1 WO2024203715 A1 WO 2024203715A1
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Prior art keywords
chloroprene
unsaturated nitrile
nitrile copolymer
mass
parts
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PCT/JP2024/011008
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English (en)
Japanese (ja)
Inventor
渉 西野
遼太郎 安藤
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Denka Co Ltd
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Denka Co Ltd
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Publication of WO2024203715A1 publication Critical patent/WO2024203715A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/30—Nitriles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
    • C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
    • C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
    • C08F236/14—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen
    • C08F236/16—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen containing halogen
    • C08F236/18—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen containing halogen containing chlorine
    • 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
    • C08L11/02—Latex

Definitions

  • the present invention relates to a chloroprene-unsaturated nitrile copolymer latex, a rubber component, a rubber composition, a vulcanized molded product, and a method for producing the chloroprene-unsaturated nitrile copolymer latex.
  • Chloroprene latex and chloroprene rubber which contain chloroprene polymers, have excellent mechanical properties, ozone resistance, and chemical resistance, and these properties are used in a wide range of fields, including automotive parts, adhesives, and various industrial rubber parts.
  • Patent Document 1 discloses a copolymer in which the proportions of the monomers constituting the polymer are, when the total amount of all monomers is taken as 100% by mass, 80 to 97% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1) and 20 to 3% by mass of 2,3-dichloro-1,3-butadiene (C-2); or a copolymer in which 79.8 to 96.8% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1), 20 to 3% by mass of 2,3-dichloro-1,3-butadiene (C-2) and 0.2 to 17% by mass of a monomer (C-3) copolymerizable therewith are
  • the present invention discloses a composition for chloroprene-based vulcanized rubber, which comprises 100 parts by mass of a polymer for chloroprene-based vulcanized rubber, the polymer being a copo
  • Patent Document 2 discloses a rubber composition for a flame-retardant hose, which contains a rubber component, carbon black, and silica, and in which the rubber component is composed only of chloroprene rubber, or is composed only of chloroprene rubber and styrene-butadiene rubber.
  • Patent Document 3 discloses a statistical copolymer latex containing chloroprene monomer units and unsaturated nitrile monomer units, with an unsaturated nitrile monomer unit content of 5 to 20% by mass, and wherein the toluene-insoluble portion of the statistical copolymer obtained by freeze-drying the statistical copolymer latex is 50 to 100% by mass relative to 100% by mass of the statistical copolymer.
  • chloroprene-based latexes have room for improvement in terms of storage stability at high temperatures for long periods of time.
  • the present invention has been made in consideration of these circumstances, and provides a chloroprene-unsaturated nitrile copolymer latex that has excellent storage stability at high temperatures for long periods of time, and that has excellent oil resistance in a vulcanized molded product of a rubber composition that uses the rubber component of the chloroprene-unsaturated nitrile copolymer latex.
  • the present invention also provides a rubber component of the chloroprene-unsaturated nitrile copolymer latex, a rubber composition that contains the rubber component, a vulcanized molded product of the rubber composition, and a method for producing the chloroprene-unsaturated nitrile copolymer latex.
  • a chloroprene-unsaturated nitrile copolymer latex containing a chloroprene-unsaturated nitrile copolymer containing chloroprene monomer units and unsaturated nitrile monomer units, the chloroprene-unsaturated nitrile copolymer having a nitrogen content of 0.5% by mass or more as measured by a combustion method, and a content of unsaturated nitrile hydrolysates in the chloroprene-unsaturated nitrile copolymer latex of 0.10 to 9.00 parts by mass per 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • R 1 represents any one of hydrogen, chlorine, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted mercapto group, and a substituted or unsubstituted heterocyclyl group.
  • a rubber component of the chloroprene-unsaturated nitrile copolymer latex according to any one of [1] to [3].
  • a rubber composition comprising the rubber component according to [4].
  • the vulcanization molded article according to [6] which is a transmission belt, a conveyor belt, a hose, a wiper, a dipping product, a sealing part, an adhesive, a boot, a rubber-coated cloth, a rubber roll, a vibration-proof rubber or a sponge product.
  • a method for producing a chloroprene-unsaturated nitrile copolymer latex containing a chloroprene-unsaturated nitrile copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit comprising a polymerization step of polymerizing raw material monomers containing a chloroprene monomer and an unsaturated nitrile monomer in an aqueous solution containing water to obtain the chloroprene-unsaturated nitrile copolymer, wherein the amount of the water is less than 150 parts by mass when the total amount of the raw material monomers used in the polymerization step is taken as 100 parts by mass.
  • the chloroprene-unsaturated nitrile copolymer latex of the present invention has excellent storage stability at high temperatures for long periods of time.
  • a vulcanized molded product of a rubber composition containing the rubber component of the chloroprene-unsaturated nitrile copolymer latex of the present invention has excellent oil resistance.
  • the chloroprene-unsaturated nitrile copolymer latex of the present invention has excellent storage stability at high temperatures for long periods of time, it can be stored while maintaining its excellent quality in the state of the chloroprene-unsaturated nitrile copolymer latex, and since a vulcanized molded product of a rubber composition using the rubber component has excellent oil resistance, these properties can be utilized for a variety of applications and components.
  • Chloroprene-unsaturated nitrile copolymer latex contains a chloroprene-unsaturated nitrile copolymer.
  • the chloroprene-unsaturated nitrile copolymer has a nitrogen content of 0.5% by mass or more as measured by a combustion method, and the content of the unsaturated nitrile hydrolysate in the chloroprene-unsaturated nitrile copolymer latex is 0.10 to 9.00 parts by mass per 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • the chloroprene-unsaturated nitrile copolymer according to the present invention may have a structure derived from a monomer unit other than the chloroprene monomer unit and the unsaturated nitrile monomer unit, as long as the object of the present invention is not impaired.
  • 2-chloro-1,3-butadiene may contain a small amount of 1-chloro-1,3-butadiene as an impurity.
  • 2-chloro-1,3-butadiene containing such a small amount of 1-chloro-1,3-butadiene can also be used as the chloroprene monomer in this embodiment.
  • unsaturated nitriles examples include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenylacrylonitrile.
  • the unsaturated nitriles may be used alone or in combination of two or more. It is preferable that the unsaturated nitrile contains acrylonitrile, from the viewpoint of easily obtaining excellent moldability, and from the viewpoint of easily obtaining excellent breaking strength, breaking elongation, hardness, tear strength, and oil resistance in the vulcanized molded product.
  • the chloroprene-unsaturated nitrile copolymer according to the present invention has a nitrogen content of 0.5% by mass or more as measured by a combustion method.
  • the nitrogen content may be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or 7.0% by mass, and may be within a range between any two of the values exemplified here.
  • the nitrogen content of the chloroprene-unsaturated nitrile copolymer can be determined by analyzing the chloroprene-unsaturated nitrile copolymer obtained by freeze-drying or methanol precipitation from the chloroprene-unsaturated nitrile copolymer latex using an elemental analyzer by a combustion method. Specifically, the analysis can be performed by the method described in the Examples.
  • the nitrogen in the chloroprene-unsaturated nitrile copolymer can be derived from the unsaturated nitrile monomer units in the chloroprene-unsaturated nitrile copolymer, and can be controlled by adjusting the amount of unsaturated nitrile in the raw material monomer during polymerization of the chloroprene-unsaturated nitrile copolymer.
  • the chloroprene-unsaturated nitrile copolymer preferably has an unsaturated nitrile monomer unit content of 2% by mass or more.
  • the unsaturated nitrile monomer unit content may be, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention preferably has an acrylonitrile bond content (content of acrylonitrile monomer units) of 2 mass% or more, measured in accordance with JIS K 6451-1.
  • the acrylonitrile bond content (content of acrylonitrile monomer units) is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mass%, and may be within a range between any two of the numerical values exemplified here.
  • the content of unsaturated nitrile monomer units and the content of acrylonitrile monomer units in the chloroprene-unsaturated nitrile copolymer can be calculated based on the nitrogen content measured by the combustion method, and in particular, the amount of acrylonitrile bonds (content of acrylonitrile monomer units) can be calculated based on JIS K 6451-1. Specifically, it can be analyzed by the method described in the Examples.
  • the resulting rubber composition and vulcanized molded product will have sufficient oil resistance.
  • the resulting rubber composition and vulcanized molded product will have improved water resistance and cold resistance.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention preferably contains 60 to 100% by mass of chloroprene monomer units when the chloroprene-unsaturated nitrile copolymer is taken as 100% by mass.
  • the content of chloroprene monomer units in the chloroprene-unsaturated nitrile copolymer may be, for example, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention may also have a monomer unit other than the chloroprene monomer and the unsaturated nitrile monomer.
  • the monomer unit other than the chloroprene monomer and the unsaturated nitrile monomer is not particularly limited as long as it is copolymerizable with the chloroprene monomer or the chloroprene monomer and the unsaturated nitrile monomer, and examples of the monomer unit include esters of (meth)acrylic acid (methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), hydroxyalkyl (meth)acrylates (2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.), 2,3-dichloro-1,3-butadiene, 1-chlor
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention may contain 0 to 20% by mass of monomer units other than the chloroprene monomer and the unsaturated nitrile monomer when the chloroprene-unsaturated nitrile copolymer is taken as 100% by mass.
  • the content of the monomer units other than the chloroprene monomer and the unsaturated nitrile monomer in the chloroprene-unsaturated nitrile copolymer may be, for example, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention may be composed only of chloroprene monomer units and unsaturated nitrile monomer units.
  • the chloroprene-unsaturated nitrile copolymer latex according to one embodiment of the present invention may contain one kind of chloroprene-unsaturated nitrile copolymer, or may contain two or more kinds of chloroprene-unsaturated nitrile copolymers.
  • the chloroprene-unsaturated nitrile copolymer latex according to one embodiment of the present invention contains two or more kinds of chloroprene-unsaturated nitrile copolymers, it is preferable that the content based on the total mass of total nitrogen, total unsaturated nitrile monomer units, total acrylonitrile monomer units, etc.
  • chloroprene-unsaturated nitrile copolymers contained in the two or more kinds of chloroprene-unsaturated nitrile copolymers is within the above-mentioned numerical range with respect to 100% by mass of the two or more kinds of chloroprene-unsaturated nitrile copolymers in total contained in the chloroprene-unsaturated nitrile copolymer latex.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention can have a functional group having a structure represented by chemical formula (1) or chemical formula (2).
  • R 1 represents any one of hydrogen, chlorine, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted mercapto group, and a substituted or unsubstituted heterocyclyl group.
  • the functional group having the structure represented by chemical formula (1) or chemical formula (2) can be introduced by carrying out the polymerization process of the chloroprene-unsaturated nitrile copolymer in the presence of a RAFT agent.
  • a RAFT agent Compounds that can be used to introduce the functional group having the structure represented by chemical formula (1) or chemical formula (2) will be described later in the section on the production method.
  • the rubber composition containing the rubber component of the chloroprene-unsaturated nitrile copolymer latex according to one embodiment of the present invention has a sufficiently long scorch time because the chloroprene-unsaturated nitrile copolymer has a functional group having a structure represented by chemical formula (1) or chemical formula (2).
  • the content of the hydrolyzate of the unsaturated nitrile in the chloroprene-unsaturated nitrile copolymer latex is 0.10 to 9.00 parts by mass per 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • unsaturated nitriles are hydrolyzed to amides, alcohols, and ethers, and are finally decomposed to carboxylic acids and ammonia.
  • the hydrolyzate of the unsaturated nitrile may contain amides, nitriles, alcohols, ethers, carboxylic acids, and ammonia derived from the unsaturated nitrile.
  • the hydrolyzate of the unsaturated nitrile may be a compound derived from the unsaturated nitrile, and may be a compound containing a cyano group, a compound containing an amide group, a compound containing a carboxy group, and a compound containing an amino group (including ammonia).
  • the hydrolysate of the unsaturated nitrile may contain acrylamide, 2-cyanoethanol, 2-cyanoethyl ether, acrylic acid, and ammonia, and may be acrylamide, 2-cyanoethanol, 2-cyanoethyl ether, acrylic acid, and ammonia.
  • the hydrolysate of the unsaturated nitrile may contain methacrylamide, 3-hydroxy-2-methylpropanenitrile, 3-(2-cyanopropoxy)-2-methylpropanenitrile, methacrylic acid, and ammonia, and may be methacrylamide, 3-hydroxy-2-methylpropanenitrile, 3-(2-cyanopropoxy)-2-methylpropanenitrile, methacrylic acid, and ammonia.
  • phenylacrylonitrile in the case of phenylacrylonitrile, it can contain 3-phenylpropionamide, ⁇ -(hydroxymethyl)benzeneacetonitrile, ⁇ , ⁇ '-[oxybis(methylene)]bis[ ⁇ -methylbenzeneacetonitrile], 2-phenylpropionic acid, and ammonia, and can be 3-phenylpropionamide, ⁇ -(hydroxymethyl)benzeneacetonitrile, ⁇ , ⁇ '-[oxybis(methylene)]bis[ ⁇ -methylbenzeneacetonitrile], 2-phenylpropionic acid, and ammonia.
  • the chloroprene-unsaturated nitrile copolymer according to the present invention has a content of unsaturated nitrile hydrolysate in the chloroprene-unsaturated nitrile copolymer latex relative to 100 parts by mass of the chloroprene-unsaturated nitrile copolymer, which is 0.10 to 9.00 parts by mass, for example, 0.10, 0.20, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, or 9.00% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention may have a total content of amide, nitrile, alcohol, ether, carboxylic acid, and ammonia derived from unsaturated nitrile within the above numerical range, and the content of amide, nitrile, alcohol, and ether derived from unsaturated nitrile may be within the above numerical range.
  • the total content of acrylamide, 2-cyanoethanol, 2-cyanoethyl ether, acrylic acid, ammonia, methacrylamide, 3-hydroxy-2-methylpropanenitrile, 3-(2-cyanopropoxy)-2-methylpropanenitrile, methacrylic acid, 3-phenylpropionamide, ⁇ -(hydroxymethyl)benzeneacetonitrile, ⁇ , ⁇ '-[oxybis(methylene)]bis[ ⁇ -methylbenzeneacetonitrile], and 2-phenylpropionic acid may be within the above numerical range, and the total content of acrylamide, 2-cyanoethanol, 2-cyanoethyl ether, methacrylamide, 3-hydroxy-2-methylpropanenitrile, 3-(2-cyanopropoxy)-2-methylpropanenitrile, 3-phenylpropionamide, ⁇ -(hydroxymethyl)benzeneacetonitrile, and ⁇ ,
  • the chloroprene-unsaturated nitrile copolymer according to the present invention is preferably such that the content of acrylonitrile hydrolysates per 100 parts by mass of the chloroprene-unsaturated nitrile copolymer in the chloroprene-unsaturated nitrile copolymer latex is within the above numerical range.
  • the content of unsaturated nitrile hydrolysates can be the total content of 2-cyanoethanol, 2-cyanoethyl ether, and acrylamide
  • the content of acrylonitrile hydrolysates can be the total content of 2-cyanoethanol, 2-cyanoethyl ether, and acrylamide.
  • the chloroprene-unsaturated nitrile copolymer according to the present invention is preferably such that the total content of 2-cyanoethanol, 2-cyanoethyl ether, and acrylamide per 100 parts by mass of the chloroprene-unsaturated nitrile copolymer in the chloroprene-unsaturated nitrile copolymer latex is within the above numerical range.
  • the chloroprene-unsaturated nitrile copolymer latex may have a 2-cyanoethanol content of 0.05 to 8.00 parts by mass relative to 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • the 2-cyanoethanol content may be, for example, 0.05, 0.10, 0.20, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, or 8.00% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer latex may have a 2-cyanoethyl ether content of 0.05 to 8.00 parts by mass relative to 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • the 2-cyanoethyl ether content may be, for example, 0.05, 0.10, 0.20, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, or 8.00 parts by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer latex may have an acrylamide content of 0.05 to 8.00 parts by mass relative to 100 parts by mass of the chloroprene-unsaturated nitrile copolymer.
  • the acrylamide content may be, for example, 0.05, 0.10, 0.20, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, or 8.00% by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention has an unsaturated nitrile hydrolysate content within the above numerical range, and therefore has excellent storage stability at high temperatures for long periods of time, and a vulcanized molded product of a rubber composition containing a rubber component of the chloroprene-unsaturated nitrile copolymer latex has excellent oil resistance.
  • the content of unsaturated nitrile hydrolysates can be controlled by adjusting the production conditions during polymerization of the chloroprene-unsaturated nitrile copolymer, in particular the amount of water and the amount of alkali relative to the raw material monomers used in polymerization, the type and amount of the raw material monomers mixed, as well as the timing of addition, polymerization temperature, and the concentration of each monomer in the polymerization liquid.
  • the content of the hydrolyzed unsaturated nitrile in the chloroprene-unsaturated nitrile copolymer latex can be determined by analyzing a solution obtained by diluting the chloroprene-unsaturated nitrile copolymer latex with tetrahydrofuran using gas chromatography, for example, a gas chromatograph (GC) system. Specifically, the analysis can be performed using the method described in the Examples. As another method, since ammonia, one of the hydrolyzed unsaturated nitriles, has a strong irritating odor, the presence or absence of the generation of ammonia can be confirmed by the presence or absence of the irritating odor in the polymerization liquid.
  • gas chromatography for example, a gas chromatograph (GC) system.
  • GC gas chromatograph
  • carboxylic acid is considered to be generated simultaneously with ammonia from the mechanism of decomposition, the presence or absence of the generation of carboxylic acid can be confirmed by the presence or absence of ammonia.
  • concentration of ammonia in the chloroprene-unsaturated nitrile copolymer latex is 1 ppm or more, the irritating odor can be detected in the working environment.
  • concentration of ammonia in the chloroprene-unsaturated nitrile copolymer latex can be less than 1 ppm.
  • the concentration of ammonia can be analyzed by ion chromatography.
  • carboxylic acid can be analyzed by ion chromatography, liquid chromatography, or gas chromatography.
  • the chloroprene-unsaturated nitrile copolymer latex according to one embodiment of the present invention can contain compounds used in the polymerization of the chloroprene-unsaturated nitrile copolymer, in addition to the chloroprene-unsaturated nitrile copolymer and the hydrolyzate of the unsaturated nitrile.
  • the chloroprene-unsaturated nitrile copolymer latex according to one embodiment of the present invention can have a solid content adjusted according to the application.
  • the solid content is not particularly limited, and may be, for example, 40, 45, 50, 55, 60, 65, or 70% by mass, or may be within a range between any two of the values exemplified here.
  • the viscosity is less than 1000 cps.
  • the viscosity after storage at 40°C for four months may be, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 950 cps, or may be within a range between any two of the values exemplified here.
  • the viscosity can be measured using a B-type viscometer, and specifically, can be analyzed by the method described in the examples.
  • a method for producing a chloroprene-unsaturated nitrile copolymer latex including a chloroprene-unsaturated nitrile copolymer including a chloroprene monomer unit and an unsaturated nitrile monomer unit can include a polymerization step of polymerizing raw material monomers including a chloroprene monomer and an unsaturated nitrile monomer in an aqueous solution containing water to obtain a chloroprene-unsaturated nitrile copolymer.
  • the total raw material monomers used in the polymerization step are taken as 100 parts by mass, the amount of the water can be less than 150 parts by mass.
  • raw material monomers including chloroprene monomer and unsaturated nitrile monomer are polymerized in an aqueous solution containing water to obtain a chloroprene-unsaturated nitrile copolymer.
  • the raw material monomers include chloroprene monomer and unsaturated nitrile monomer, and may include other monomers in addition to chloroprene monomer and unsaturated nitrile monomer.
  • the other monomers are as described above. It is preferable to adjust the blending ratio of each monomer in the raw material monomers so that the content of chloroprene monomer units, unsaturated nitrile monomer units, and other monomer units in the resulting chloroprene-unsaturated nitrile copolymer falls within the numerical ranges described above.
  • a portion of the raw material monomers can be added initially, and a portion can be added in portions after the start of polymerization.
  • the polymerization process can include a first addition step of adding at least a portion of the raw material monomers including chloroprene and unsaturated nitrile, and a second addition step of adding the remaining raw material monomers.
  • the total amount of chloroprene monomers added in the polymerization step is taken as 100 parts by mass, at least 10 parts by mass of chloroprene monomer can be added, for example, 10, 20, 30, 40, 50, 60, or 70 parts by mass can be added, and may be within a range between any two of the numerical values exemplified here.
  • the first addition step when the total amount of unsaturated nitriles added in the polymerization step is taken as 100 parts by mass, at least 50 parts by mass of unsaturated nitrile can be added, for example, 50, 60, 70, 80, 90, or 100 parts by mass can be added, and may be within a range between any two of the numerical values exemplified here.
  • the raw material monomer, emulsifier, and optionally RAFT agent and molecular weight are added to water in the above amounts. Then, a polymerization initiator is added to start polymerization.
  • the second addition step when the total amount of chloroprene monomer added in the polymerization step is 100 parts by mass, at least 30 parts by mass of chloroprene monomer can be added, for example, 30, 40, 50, 60, or 70 parts by mass can be added, and may be within a range between any two of the numerical values exemplified here.
  • the total amount of unsaturated nitrile added in the polymerization step is 100 parts by mass, 0, 10, 20, or 30 parts by mass of unsaturated nitrile can be added, and may be within a range between any two of the numerical values exemplified here.
  • the remaining raw material monomer in two or more separate portions.
  • the remaining raw material monomer can be added in separate portions, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20 portions, and the number of separate additions may be within a range between any two of the numerical values exemplified here.
  • the remaining raw material monomers can also be added continuously at a constant flow rate.
  • the raw material monomers in portions so that the amount of unsaturated nitrile monomer in the polymerization liquid is maintained at 20 to 90 parts by mass when the amount of unreacted monomer in the polymerization liquid (e.g., the total of chloroprene monomer and acrylonitrile monomer) is 100 parts by mass.
  • the amount of unsaturated nitrile monomer relative to 100 parts by mass of unreacted monomer in the polymerization liquid is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 parts by mass, and may be within a range between any two of the numerical values exemplified here.
  • the amount of water can be less than 150 parts by mass when the total amount of raw material monomers used in the polymerization step is 100 parts by mass.
  • the amount of water can be, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 149 parts by mass, or can be within a range between any two of the values exemplified here.
  • the amount of hydrolyzed unsaturated nitriles produced can be reduced by reducing the amount of water compared to conventional production methods.
  • hydrolyzed unsaturated nitriles such as acrylamide, 2-cyanoethanol, and 2-cyanoethyl ether
  • acrylamide, 2-cyanoethanol, and 2-cyanoethyl ether impose a large burden on wastewater treatment, and therefore reducing the production of these hydrolyzed products is also advantageous in terms of reducing the environmental load and the effort and cost required for wastewater treatment.
  • the emulsifier used in emulsion polymerization is not particularly limited, and any known emulsifier generally used in emulsion polymerization of chloroprene polymers can be used.
  • emulsifiers include alkali metal salts of saturated or unsaturated fatty acids having 6 to 22 carbon atoms, alkali metal salts of rosin acid or disproportionated rosin acid (e.g. potassium rosinate), and alkali metal salts of formalin condensates of ⁇ -naphthalenesulfonic acid (e.g. sodium salt).
  • the amount of emulsifier added is preferably 0.2 to 20 parts by mass, and more preferably 2 to 10 parts by mass, per 100 parts by mass of the total raw material monomers used in the polymerization process.
  • the molecular weight regulator used in emulsion polymerization is not particularly limited, and any known molecular weight regulator commonly used in emulsion polymerization of chloroprene can be used, such as mercaptan compounds, xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds.
  • molecular weight regulators for the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds can be suitably used.
  • a known radical polymerization initiator can be used, such as potassium persulfate, benzoyl peroxide, hydrogen peroxide, and azo compounds.
  • a RAFT agent can be used, and by carrying out polymerization in the presence of a known RAFT agent, the terminal structure represented by chemical formula (1) or chemical formula (2) can be introduced into the chloroprene-unsaturated nitrile copolymer.
  • R 1 represents any one of hydrogen, chlorine, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted mercapto group, and a substituted or unsubstituted heterocyclyl group.
  • the compound leading to the structure represented by the above chemical formula (1) is not particularly limited, and general compounds can be used, such as dithiocarbamates and dithioesters.
  • benzyl 1-pyrrole carbodithioate (common name: benzyl 1-pyrrole dithiocarbamate), benzyl phenyl carbodithioate, 1-benzyl-N,N-dimethyl-4-aminodithiobenzoate, 1-benzyl-4-methoxydithiobenzoate, 1-phenylethyl imidazole carbodithioate (common name: 1-phenylethyl imidazole dithiocarbamate), benzyl-1-(2-pyrrolidinone) carbodithioate, (Common name: benzyl-1-(2-pyrrolidinone)dithiocarbamate), benzyl phthalimidyl carbodithioate, (Common name: benzyl phthalimidyl car
  • the compound leading to the structure represented by the above chemical formula (2) is not particularly limited and general compounds can be used, for example, 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]thio]thio]thio]
  • trithiocarbonates include 2-methylpropionic acid, 2,2'-[carbonothioylbis(thio)]bis[2-methylpropionic acid], 2-amino-1-methyl-2-
  • the amount of the RAFT agent added can be 0.05 to 10 parts by mass relative to 100 parts by mass of the raw material monomer, for example, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass, and may be within a range between any two of the numerical values exemplified here.
  • the chloroprene-unsaturated nitrile copolymer according to one embodiment of the present invention has a terminal structure represented by chemical formula (1) or chemical formula (2), and thus can sufficiently extend the scorch time of a rubber composition containing a rubber component of the chloroprene-unsaturated nitrile copolymer latex.
  • the polymerization temperature and the final conversion rate of the monomer are not particularly limited, but the polymerization temperature may be, for example, 0 to 50°C or 10 to 50°C.
  • the polymerization may be carried out so that the final conversion rate of the monomer falls within the range of 40 to 95% by mass.
  • a polymerization terminator that stops the polymerization reaction may be added to terminate the polymerization when the desired conversion rate is reached.
  • polymerization terminator there are no particular limitations on the polymerization terminator, and any known polymerization terminator commonly used in emulsion polymerization of chloroprene can be used.
  • polymerization terminators include phenothiazine (thiodiphenylamine), 4-t-butylcatechol, and 2,2-methylenebis-4-methyl-6-t-butylphenol.
  • freezing stabilizers emulsion stabilizers, viscosity modifiers, antioxidants, preservatives, etc. can be added as desired after polymerization, within the scope that does not impair the effects of the present invention.
  • Rubber component of chloroprene-unsaturated nitrile copolymer latex is the rubber component of the chloroprene-unsaturated nitrile copolymer.
  • the method for obtaining the rubber component of the chloroprene-unsaturated nitrile copolymer latex is not particularly limited.
  • the rubber component of the chloroprene-unsaturated nitrile copolymer can be obtained by mixing the chloroprene-unsaturated nitrile copolymer latex with a large amount of methanol, precipitating, filtering, and drying.
  • the rubber component of the chloroprene-unsaturated nitrile copolymer can be obtained by freeze-drying the chloroprene-unsaturated nitrile copolymer latex, specifically, by adjusting the pH of the chloroprene-unsaturated nitrile copolymer latex, freeze-drying, washing with water, and drying with hot air.
  • the rubber component of the chloroprene-unsaturated nitrile copolymer includes a methanol precipitate of the chloroprene-unsaturated nitrile copolymer latex and a freeze-dried product of the chloroprene-unsaturated nitrile copolymer latex.
  • the rubber component according to one embodiment of the present invention when made into a rubber composition having the composition described in the examples, preferably has a scorch time of 11 minutes or more.
  • the scorch time can be determined by performing a Mooney scorch test based on JIS K 6300-1 using an L-type rotor at a test temperature of 125°C, and measuring the time at which the measured Mooney viscosity increases by 5M.
  • the scorch time can be controlled by adjusting the manufacturing conditions during polymerization of the chloroprene-unsaturated nitrile copolymer, in particular by adjusting the type and amount of the raw material blend and the terminal structure of the chloroprene-unsaturated nitrile copolymer.
  • a rubber composition having the composition described in the examples is prepared, and the rubber composition is press-vulcanized at 170°C for 20 minutes in accordance with JIS K 6250 to produce a vulcanized molded product.
  • a test oil high-grade automotive lubricating oil, ASTM No. 3, IRM 903 oil
  • the volume change is preferably less than 45% by mass.
  • the rubber composition according to one embodiment of the present invention includes the above-mentioned rubber component.
  • the rubber composition according to the present invention may include a vulcanizing agent, a vulcanization accelerator, an antioxidant, a filler, a reinforcing material, a silane coupling agent, a plasticizer, a softener, a lubricant, a processing aid, and may further include components such as a stabilizer, a flame retardant, and a vulcanization retarder, as long as the effects of the present invention are not impaired.
  • the rubber composition according to the present invention may contain a vulcanizing agent.
  • the type of vulcanizing agent is not particularly limited as long as it does not impair the effects of the present invention.
  • the vulcanizing agent is preferably a vulcanizing agent that can be used for vulcanizing chloroprene-based rubber.
  • One or more vulcanizing agents may be freely selected and used. Examples of the vulcanizing agent include sulfur, zinc oxide, and organic peroxide.
  • metal oxide is zinc oxide.
  • the metal oxide preferably contains zinc oxide, and more preferably is zinc oxide.
  • organic peroxides include dicumyl peroxide, benzoyl peroxide, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, diisobutyryl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t- Hexyl peroxypivalate, t-butyl peroxypivalate, di
  • At least one selected from dicumyl peroxide, 1,4-bis[(t-butylperoxy)isopropyl]benzene, t-butyl- ⁇ -cumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 is preferred, with 1,4-bis[(t-butylperoxy)isopropyl]benzene being particularly preferred.
  • the rubber composition according to the present invention preferably contains 3 to 15 parts by mass of a vulcanizing agent relative to the rubber component contained in the rubber composition, from the viewpoint of ensuring processing safety and being able to obtain a good vulcanizate.
  • the content of the vulcanizing agent is, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by mass relative to 100 parts by mass of the rubber component contained in the rubber composition, and may be within a range between any two of the numerical values exemplified here.
  • the rubber composition according to one embodiment of the present invention may contain an acid acceptor.
  • the acid acceptor include magnesium oxide, lead oxide, lead tetroxide, iron trioxide, titanium dioxide, calcium oxide, and hydrotalcite.
  • hydrotalcite one represented by the following formula may be used. [M 2+ 1-x M 3+ x (OH) 2 ] x+ [A n-x/n ⁇ mH 2 O] x-
  • M 2+ at least one divalent metal ion selected from Mg 2+ , Zn 2+ , etc.
  • M 3+ at least one trivalent metal ion selected from Al 3+ , Fe 3+ , etc.
  • a n- at least one n-type anion selected from CO 3 2- , Cl - , NO 3 2- , etc.
  • X 0 ⁇ X ⁇ 0.33.
  • hydrotalcite examples include Mg4.3Al2 ( OH ) 12.6CO3.3.5H2O , Mg3ZnAl2 (OH) 12CO3.3H2O , Mg4.5Al2 ( OH ) 13CO3.3.5H2O , Mg4.5Al2 ( OH ) 13CO3 , Mg4Al2 ( OH ) 12CO3.3.5H2O , Mg6Al2 ( OH ) 16CO3.4H2O , Mg5Al2 ( OH ) 14CO3.4H2O , and Mg3Al2 ( OH ) 10CO3.1.7H2O .
  • Particularly preferred is Mg4.3 Al2 ( OH ) 12.6CO3.3.5H2O , Mg3ZnAl2 ( OH ) 12CO3.3H2O .
  • the amount of acid acceptor added may be 0.1 to 15 parts by mass per 100 parts by mass of the rubber component.
  • the amount of hydrotalcite added may be, for example, 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by mass, and may be within a range between any two of the numerical values exemplified here. Hydrotalcite may be used alone or in combination of two or more types.
  • the rubber composition according to the present invention may contain a vulcanization accelerator, and may contain 0.3 to 5.0 parts by mass of the vulcanization accelerator relative to 100 parts by mass of the rubber composition contained in the rubber composition.
  • the content of the vulcanization accelerator is, for example, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 parts by mass, and may be within a range between any two of the numerical values exemplified here.
  • the rubber composition according to the present invention may not contain a vulcanization accelerator.
  • the type of vulcanization accelerator is not particularly limited as long as it does not impair the effects of the present invention.
  • the vulcanization accelerator is preferably one that can be used for vulcanization of chloroprene-based rubber.
  • One or more vulcanization accelerators can be freely selected and used. Examples of vulcanization accelerators include thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthogenate-based, and thiazole-based.
  • thiuram vulcanization accelerators examples include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide.
  • TMTD tetramethylthiuram disulfide
  • TMTD tetraethylthiuram disulfide
  • tetrabutylthiuram disulfide examples include tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide.
  • dithiocarbamate vulcanization accelerator examples include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, and tellurium diethyldithiocarbamate.
  • thiourea-based vulcanization accelerator examples include thiourea compounds such as ethylene thiourea, diethyl thiourea (N,N'-diethyl thiourea), trimethyl thiourea, diphenyl thiourea (N,N'-diphenyl thiourea), and 1,3-trimethylene-2-thiourea.
  • guanidine-based vulcanization accelerator include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salts of dicatechol borate.
  • Examples of the xanthogenate-based vulcanization accelerator include zinc butylxanthogenate and zinc isopropylxanthogenate.
  • Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, 2-mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole cyclohexylamine salt, 2-(4'-morpholinodithio)benzothiazole, and N-cyclohexylbenzothiazole-2-sulfenamide. These may be used alone or in combination of two or more.
  • the rubber composition according to the present invention may contain a filler.
  • the filler (reinforcing material) include furnace carbon black such as SAF, ISAF, HAF, EPC, XCF, FEF, GPF, HMF, and SRF, modified carbon black such as hydrophilic carbon black, channel black, lamp black, thermal carbon such as FT and MT, acetylene black, ketjen black, silica, clay, talc, and calcium carbonate. These may be used alone or in combination of two or more.
  • the rubber composition according to one embodiment of the present invention may contain 5 to 130 parts by mass of a filler per 100 parts by mass of the rubber component.
  • the filler content may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, or 130 parts by mass, or may be within a range between any two of the numerical values exemplified here.
  • the rubber composition according to one embodiment of the present invention can appropriately adjust the hardness of the vulcanized molded body.
  • the rubber composition according to one embodiment of the present invention may contain a silane coupling agent.
  • a silane coupling agent is not particularly limited, and those used in commercially available rubber compositions can be used, for example, vinyl coupling agents, epoxy coupling agents, styryl coupling agents, methacrylic coupling agents, acrylic coupling agents, amino coupling agents, polysulfide coupling agents, and mercapto coupling agents.
  • vinyl coupling agents, methacrylic coupling agents, and acrylic coupling agents that start reacting under high temperature conditions during crosslinking are preferred.
  • the rubber composition according to one embodiment of the present invention may contain 0.5 to 15 parts by mass of a silane coupling agent per 100 parts by mass of silica contained in the rubber composition, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by mass, and may be within a range between any two of the numerical values exemplified here. These may be used alone or in combination of two or more.
  • the plasticizer is not particularly limited as long as it is compatible with the chloroprene-unsaturated nitrile copolymer rubber, and examples thereof include vegetable oils such as rapeseed oil, phthalate-based plasticizers, DOS (dioctyl sebacate), DBS (dibutyl sebacate), DOA (dioctyl adipate), ester-based plasticizers, ether ester-based plasticizers, thioether-based plasticizers, aromatic oils, naphthenic oils, and the like. These can be used alone or in combination of two or more.
  • vegetable oils such as rapeseed oil, phthalate-based plasticizers, DOS (dioctyl sebacate), DBS (dibutyl sebacate), DOA (dioctyl adipate), ester-based plasticizers, ether ester-based plasticizers, thioether-based plasticizers, aromatic oils, naphthenic oils,
  • the amount of plasticizer added can be 0 to 50 parts by mass relative to 100 parts by mass of the rubber component contained in the rubber composition, and may be, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, and may be within the range between any two of the numerical values exemplified here.
  • the rubber composition according to the present invention may further contain a lubricant and/or a processing aid.
  • the lubricant and processing aid are mainly added to improve processability, such as making the rubber composition easier to peel off from rolls, molding dies, extruder screws, etc.
  • Examples of the lubricant and processing aid include fatty acids such as stearic acid, paraffin processing aids such as polyethylene, fatty acid amides, vaseline, factice, etc. These may be used alone or in combination of two or more.
  • the rubber composition according to the present invention may contain 0.5 to 15 parts by mass of the lubricant and processing aid per 100 parts by mass of the rubber component, and may also be 1 to 10 parts by mass.
  • the content of the lubricant and processing aid may be, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by mass, and may be within a range between any two of the numerical values exemplified here.
  • the rubber composition according to the present invention may further contain components such as an antiaging agent, an antioxidant, a flame retardant, and a vulcanization retarder, as long as the effects of the present invention are not impaired.
  • the antiaging agent and the antioxidant include ozone antiaging agents, phenolic antiaging agents, amine antiaging agents, acrylate antiaging agents, imidazole antiaging agents, aromatic secondary amine antiaging agents, carbamic acid metal salts, waxes, phosphorus antiaging agents, and sulfur antiaging agents.
  • the imidazole antiaging agents include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and zinc salts of 2-mercaptobenzimidazole.
  • the rubber composition according to the present invention may contain 0.1 to 10 parts by mass of the antiaging agent and the antioxidant in total, relative to 100 parts by mass of the rubber component contained in the rubber composition.
  • the rubber composition according to one embodiment of the present invention preferably has a scorch time of 11 minutes or more.
  • the scorch time is determined by performing a Mooney scorch test based on JIS K 6300-1 using an L-type rotor at a test temperature of 125°C, and measuring the time when the measured Mooney viscosity increases by 5M.
  • the rubber composition according to one embodiment of the present invention is obtained by kneading the rubber component of the chloroprene-unsaturated nitrile copolymer latex and other necessary components at a temperature equal to or lower than the vulcanization temperature.
  • the device for kneading the raw material components include conventional kneading devices such as a mixer, a Banbury mixer, a kneader mixer, and an open roll.
  • Unvulcanized molded body, vulcanized product, and vulcanized molded body uses the rubber composition according to one embodiment of the present invention, and is a molded body (molded product) of the rubber composition (unvulcanized state) according to one embodiment of the present invention.
  • the manufacturing method of the unvulcanized molded body according to one embodiment of the present invention includes a step of molding the rubber composition (unvulcanized state) according to one embodiment of the present invention.
  • the unvulcanized molded body according to one embodiment of the present invention is made of the rubber composition (unvulcanized state) according to one embodiment of the present invention.
  • the vulcanizate according to one embodiment of the present invention is a vulcanizate of the rubber composition according to one embodiment of the present invention.
  • the method for producing the vulcanizate according to one embodiment of the present invention includes a step of vulcanizing the rubber composition according to one embodiment of the present invention.
  • the vulcanized molded product according to one embodiment of the present invention is a vulcanized molded product of a rubber composition according to one embodiment of the present invention.
  • the vulcanized molded product according to one embodiment of the present invention uses a vulcanizate according to one embodiment of the present invention, and is a molded product (molded article) of the vulcanizate according to one embodiment of the present invention.
  • the vulcanized molded product according to one embodiment of the present invention is made of a vulcanizate according to one embodiment of the present invention.
  • the vulcanized molded product according to one embodiment of the present invention can be obtained by molding a vulcanized product obtained by vulcanizing a rubber composition (unvulcanized state) according to one embodiment of the present invention, and can also be obtained by vulcanizing a molded product obtained by molding a rubber composition (unvulcanized state) according to one embodiment of the present invention.
  • the vulcanized molded product according to one embodiment of the present invention can be obtained by vulcanizing a rubber composition according to one embodiment of the present invention after or during molding.
  • the method for producing a vulcanized molded product according to one embodiment of the present invention includes a step of molding a vulcanized product according to one embodiment of the present invention, or a step of vulcanizing an unvulcanized molded product according to one embodiment of the present invention.
  • the vulcanized molded article according to one embodiment of the present invention preferably undergoes a volume change of less than 45% by mass when immersed in a test oil (high-strength automotive lubricating oil, ASTM No. 3, IRM 903 oil) at 130°C for 72 hours.
  • a test oil high-strength automotive lubricating oil, ASTM No. 3, IRM 903 oil
  • the unvulcanized molded product, vulcanized product, and vulcanized molded product according to one embodiment of the present invention can be used as rubber parts in various industrial fields such as buildings, structures, ships, railways, coal mines, and automobiles.
  • the rubber composition according to the present invention has excellent oil resistance and can be used as various components where these properties are required.
  • the rubber composition, vulcanized product, and vulcanized molded product according to one embodiment of the present invention can be used as rubber parts in various industrial fields such as buildings, structures, ships, railways, coal mines, and automobiles, and can be used for rubber parts such as automotive rubber parts (e.g., automotive seal materials), hose materials, rubber molded products, gaskets, rubber rolls, industrial cables, industrial conveyor belts, and sponges. In particular, they can be used as transmission belts, conveyor belts, hoses, wipers, immersion products, seal parts, adhesives, boots, rubber-coated cloth, rubber rolls, vibration-proof rubber, or sponge products.
  • automotive rubber parts e
  • Rubber components for automobiles include gaskets, oil seals, and packings, which are components that prevent leakage of liquids and gases and intrusion of garbage and foreign objects such as rainwater and dust into machines and devices.
  • gaskets used for fixed applications and oil seals and packings used for moving parts and movable parts.
  • various materials are used according to the purpose, as opposed to soft gaskets such as O-rings and rubber sheets.
  • packings are used for rotating parts such as the shafts of pumps and motors, movable parts of valves, reciprocating parts such as pistons, connecting parts of couplers, water stop parts of water faucets, etc.
  • the rubber composition of the present invention can improve oil resistance. This makes it possible to manufacture automobile parts with excellent oil resistance, which was difficult to do with conventional rubber compositions.
  • Hose materials are flexible pipes, and specifically include high- and low-pressure hoses for water supply, oil supply, air supply, steam, hydraulic pressure, etc.
  • the rubber composition of the present invention can improve the oil resistance of the hose material while maintaining the processability of the unvulcanized product. This makes it possible to manufacture, for example, a hose material with excellent oil resistance, which was difficult to achieve with conventional rubber compositions.
  • Rubber molded products include anti-vibration rubber, vibration-damping materials, boots, etc.
  • Anti-vibration rubber and vibration-damping materials are rubbers that prevent the transmission and spread of vibrations, and specifically include torsional dampers, engine mounts, muffler hangers, etc. for automobiles and various vehicles that absorb vibrations during engine operation to prevent noise.
  • the rubber composition of the present invention can improve the oil resistance of anti-vibration rubber and vibration-damping materials. This makes it possible to produce anti-vibration rubber and vibration-damping materials with excellent oil resistance, which was difficult to achieve with conventional rubber compositions.
  • a boot is a bellows-shaped member whose outer diameter gradually increases from one end to the other end, and specifically includes boots for constant velocity joint covers, boots for ball joint covers (dust cover boots), boots for rack and pinion gears, etc., for protecting drive parts of automobile drive systems, etc.
  • the rubber composition of the present invention can improve oil resistance. This makes it possible to manufacture boots that can be used in harsher environments than conventional rubber compositions.
  • Gaskets, oil seals and packings are components that prevent leakage of liquids or gases and intrusion of garbage or foreign objects such as rainwater or dust into machines or equipment.
  • gaskets used for fixed applications and oil seals and packings used for moving parts.
  • various materials are used according to the purpose, as opposed to soft gaskets such as O-rings and rubber sheets.
  • packings are used for rotating parts such as the shafts of pumps and motors, moving parts of valves, reciprocating parts such as pistons, connecting parts of couplers, water stop parts of water faucets, etc.
  • the rubber composition of the present invention can increase the oil resistance of these members. This makes it possible to manufacture sealing members with excellent oil resistance, which was difficult to achieve with conventional rubber compositions.
  • Rubber roll A rubber roll is manufactured by adhesively covering a metal core such as an iron core with rubber, and is generally manufactured by spirally winding a rubber sheet around a metal iron core. Rubber materials such as NBR, EPDM, and CR are used for rubber rolls according to the required characteristics of various applications such as papermaking, various metal manufacturing, film manufacturing, printing, general industrial use, agricultural machinery such as rice hullers, and food processing. CR has good mechanical strength that can withstand the friction of the objects being transported, so it is used in a wide range of rubber roll applications. Furthermore, rubber rolls that transport heavy objects have the problem of being deformed by load, and improvements are required.
  • the rubber composition of the present invention can increase the oil resistance of the rubber roll. This makes it possible to manufacture an embossing rubber roll with excellent oil resistance, which was difficult to achieve with conventional rubber compositions.
  • An industrial cable is a linear member for transmitting electrical or optical signals. It is made by covering a good conductor such as copper or a copper alloy, or an optical fiber, with an insulating covering layer, and a wide variety of industrial cables are manufactured depending on their structure and installation location.
  • the rubber composition of the present invention can improve the oil resistance of industrial cables. This makes it possible to manufacture industrial cables with excellent oil resistance, which was difficult to achieve with conventional rubber compositions.
  • Industrial conveyor belts are available in rubber, resin, and metal, and are selected according to a wide variety of uses. Among these, rubber conveyor belts are inexpensive and widely used, but when used in an environment where friction and collision with conveyed goods are frequent, they tend to deteriorate and break.
  • the rubber composition of the present invention can improve the oil resistance of industrial conveyor belts. This makes it possible to manufacture industrial conveyor belts with excellent oil resistance that can be used in harsh environments, which was difficult with conventional rubber compositions.
  • a sponge is a porous material with numerous fine holes inside, and is specifically used in vibration-proofing materials, sponge seal parts, wet suits, shoes, etc.
  • the rubber composition of the present invention can improve the acid resistance and water resistance of the sponge.
  • a chloroprene-unsaturated nitrile copolymer rubber is used, it is also possible to improve the flame retardancy of the sponge. This makes it possible to produce a sponge with excellent oil resistance and flame retardancy that can be used in harsh environments, which was difficult with conventional rubber compositions.
  • the hardness of the resulting sponge can be appropriately adjusted by adjusting the content of the foaming agent, etc.
  • Methods for molding the rubber composition (unvulcanized state) and vulcanized product according to one embodiment of the present invention include press molding, extrusion molding, calendar molding, and the like.
  • the temperature for vulcanizing the rubber composition may be set appropriately according to the composition of the rubber composition, and may be 140 to 220°C, or 160 to 190°C.
  • the vulcanization time for vulcanizing the rubber composition may be set appropriately according to the composition of the rubber composition, the shape of the unvulcanized molded product, and the like.
  • Example 1 A 3-liter polymerization vessel equipped with a heating/cooling jacket and a stirrer was charged with 23 parts by mass of chloroprene monomer, 35 parts by mass of acrylonitrile monomer, 100 parts by mass of pure water, 5.0 parts by mass of disproportionated potassium rosinate (manufactured by Harima Chemicals Co., Ltd.), 0.4 parts by mass of potassium hydroxide, 1.0 part by mass of sodium salt of ⁇ -naphthalenesulfonic acid formalin condensate (manufactured by Kao Corporation), and 0.2 parts by mass of butylbenzyl trithiocarbonate.
  • 0.1 parts by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out under a nitrogen stream at a polymerization temperature of 40° C.
  • the chloroprene monomer was added in portions so that the amount of the unsaturated nitrile monomer in the polymerization liquid was maintained at 70 parts by mass ⁇ 20 parts by mass when the amount of unreacted monomers in the polymerization liquid (the total of the chloroprene monomer and the acrylonitrile monomer) was taken as 100 parts by mass.
  • the chloroprene monomer was added in portions 20 seconds after the start of polymerization, and the amount of the portion added was adjusted with an electromagnetic valve based on the change in the heat quantity of the refrigerant for 10 seconds from the start of polymerization, and the flow rate was readjusted every 10 seconds thereafter, so that the polymerization was carried out continuously.
  • the polymerization rate relative to the total amount of chloroprene and acrylonitrile reached 65%, 0.02 parts by mass of phenothiazine, a polymerization terminator, was added to terminate the polymerization.
  • unreacted monomers, organic solvents, etc. were removed by distillation under reduced pressure, and the residue was concentrated to obtain a chloroprene-unsaturated nitrile copolymer latex 1 having a solid content of 50% by mass.
  • Example 2 Chloroprene-unsaturated nitrile copolymer latexes 2 and 4 to 7 were obtained in the same manner as in Example 1, except that the amount of chloroprene monomer initially added, the amount of acrylonitrile monomer, the amount of water, the amount of chloroprene monomer dividedly added, and the amount of unsaturated nitrile monomer relative to the unreacted monomer in the polymerization liquid maintained during polymerization were as shown in Table 1.
  • Example 3 A chloroprene-unsaturated nitrile copolymer latex 3 was obtained in the same manner as in Example, except that the amount of chloroprene monomer initially added, the amount of acrylonitrile monomer, the amount of water, the amount of chloroprene monomer added in portions, and the amount of unsaturated nitrile monomer relative to the unreacted monomer in the polymerization liquid maintained during polymerization were as shown in Table 1, and 0.5 part by mass of diisopropyl xanthogen disulfide was used instead of 0.2 part by mass of the RAFT agent.
  • the evaluation was based on the following criteria. ⁇ : Less than 1000 cps ⁇ : 1000 cps or more
  • the nitrogen content in the chloroprene-unsaturated nitrile copolymer was measured by a combustion method using the chloroprene-acrylonitrile copolymers 1 to 7, and the amount of bound acrylonitrile was calculated from the nitrogen content.
  • the analysis method was based on JIS K6451-1:2016, and an automatic analyzer was used to calculate the nitrogen content in the sample by the combustion method (Dumas method), and the content of acrylonitrile monomer units (bound acrylonitrile amount) was calculated from the nitrogen content.
  • an elemental analyzer (Sumigraph 220F: manufactured by Sumika Chemical Analysis Center Co., Ltd.) was used to measure the nitrogen atom content in 100 mg of chloroprene-unsaturated nitrile copolymer, and the content of acrylonitrile monomer units was calculated. Elemental analysis was performed as follows. The electric furnace temperatures were set at 900°C for the reactor, 600°C for the reduction furnace, 70°C for the column, and 100°C for the detector, and oxygen gas was flowed at 0.2 mL/min as the combustion gas and helium gas was flowed at 80 mL/min as the carrier gas. A calibration curve was created using aspartic acid (10.52%), which has a known nitrogen content, as the standard substance.
  • Rubber compositions were prepared using the rubber components (chloroprene-acrylonitrile copolymers 1 to 7) in the chloroprene-unsaturated nitrile copolymer latexes obtained by freeze-drying the chloroprene-acrylonitrile copolymer latexes 1 to 7 as described above.
  • Antiaging agent (4,4'-bis( ⁇ , ⁇ -dimethylbenzyl)diphenylamine (Nocrac CD, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) 3 parts by mass
  • Antiaging agent N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Nocrac 6C)) 1 part by mass
  • Acid acceptor magnesium oxide (Kyowamag 150, manufactured by Kyowa Chemical Industry Co., Ltd.) 4 parts by mass
  • Zinc oxide manufactured by Sakai Chemical Industry Co., Ltd., zinc oxide type 2
  • vulcanization accelerator trimethylthiourea (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noccela TMU)
  • Filler carbon black FEF (Asahi Carbon Co., Ltd., Asa
  • the scorch times of rubber compositions 1 to 7 were evaluated. Specifically, a Mooney scorch test was carried out for each rubber composition based on JIS K 6300-1 using an L-type rotor at a test temperature of 125°C. The time required for the measured Mooney viscosity to increase by 5M was defined as the scorch time. The obtained scorch times were evaluated according to the following evaluation criteria. ⁇ : 11 minutes or more ⁇ : Less than 11 minutes
  • Vulcanized molded articles were produced using the above-mentioned rubber compositions 1 to 7. Specifically, the obtained rubber compositions 1 to 7 were press-vulcanized under conditions of 170°C x 20 minutes based on JIS K 6250 to produce sheet-shaped vulcanized molded articles having a thickness of 2 mm. (Oil resistance) A test piece measuring 25 mm in length and 20 mm in width was punched out from the sheet-like vulcanized molded product. The test piece was immersed in a test oil (high-grade lubricating oil for automobiles, ASTM No. 3, IRM 903 oil) at 130°C for 72 hours. The volume change rate ⁇ V was calculated according to JIS K 6258. The volume change rate ⁇ V was evaluated according to the following criteria. ⁇ : Less than 45% ⁇ : 45% or more

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

L'invention concerne un latex copolymère chloroprène-nitrile insaturé présentant une excellente stabilité au stockage de longue durée à haute température, une composition de caoutchouc présentant une excellente résistance à l'huile pouvant être obtenue à l'aide d'un composant en caoutchouc à base du latex copolymère chloroprène-nitrile insaturé. La présente invention concerne un latex copolymère chloroprène-nitrile insaturé comprenant un copolymère chloroprène-nitrile insaturé contenant un motif monomère chloroprène et un motif monomère nitrile insaturé, la teneur en azote du copolymère chloroprène-nitrile insaturé étant au moins égale à 0,5 % en masse comme mesuré par un procédé de combustion, et la teneur en un hydrolysat de nitrile insaturé du latex copolymère chloroprène-nitrile insaturé variant de 0,10 à 9,00 parties en masse pour 100 parties en masse du copolymère chloroprène-nitrile insaturé.
PCT/JP2024/011008 2023-03-28 2024-03-21 Latex copolymère de chloroprène-nitrile insaturé, composant en caoutchouc, composition de caoutchouc, moulage vulcanisé et procédé de production d'un latex copolymère chloroprène-nitrile insaturé Pending WO2024203715A1 (fr)

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JP2023-052362 2023-03-28

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4857920A (fr) * 1971-11-13 1973-08-14
JPS5599907A (en) * 1979-01-27 1980-07-30 Denki Kagaku Kogyo Kk Copolymerization of chloroprene with unsaturated nitrile
WO2019017470A1 (fr) * 2017-07-21 2019-01-24 デンカ株式会社 Polymère de chloroprène et son procédé de production
WO2019211975A1 (fr) * 2018-05-02 2019-11-07 デンカ株式会社 Latex de copolymère statistique et utilisation correspondante et procédé de production pour latex de copolymère statistique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4857920A (fr) * 1971-11-13 1973-08-14
JPS5599907A (en) * 1979-01-27 1980-07-30 Denki Kagaku Kogyo Kk Copolymerization of chloroprene with unsaturated nitrile
WO2019017470A1 (fr) * 2017-07-21 2019-01-24 デンカ株式会社 Polymère de chloroprène et son procédé de production
WO2019211975A1 (fr) * 2018-05-02 2019-11-07 デンカ株式会社 Latex de copolymère statistique et utilisation correspondante et procédé de production pour latex de copolymère statistique

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