Rubber composition, vulcanized product, and vulcanized molded body

Abstract

To provide a rubber composition that makes it possible to obtain a vulcanized product and a vulcanized molded body having better compression set resistance and bending fatigue resistance than in the past. The present invention provides a rubber composition containing chloroprene rubber and a crosslinking agent A, wherein the chloroprene rubber contains chloroprene rubber containing an unsaturated nitrile monomer unit, and the crosslinking agent A has an alkylphenol structure.

Description

Rubber composition, vulcanizate, and vulcanized molded product

[0001] The present invention relates to a rubber composition, a vulcanizate, and a vulcanized molded article.

[0002] Taking advantage of their properties, rubber compositions are used in a wide range of fields, such as general industrial power transmission belts and conveyor belts, automotive air springs, vibration-isolating rubber, hoses, wipers, dipped products, sealing parts, adhesives, boots, rubber-coated fabrics, rubber rolls, etc. In recent years, the properties required of rubber parts have increased significantly.

[0003] Patent Document 1 discloses a rubber composition for tire vulcanization bladders, characterized by blending 1 to 20 parts by mass of an alkylphenol formaldehyde condensate and 0.1 to 10 parts by mass of a citraconic imide compound with 100 parts by mass of a rubber component containing 90 parts by mass or more of a butyl-based rubber consisting of butyl rubber and / or halogenated butyl rubber. Patent Document 2 discloses a rubber composition for bladders, which contains a rubber component containing a butyl-based rubber and zinc oxide having an average primary particle size of 15 to 190 nm.

[0004] JP 2016-098294 A JP 2010-285225 A

[0005] However, it has been difficult to simultaneously achieve improvements in compression set resistance and flex fatigue resistance in vulcanizates and vulcanized molded articles obtained from conventional rubber compositions. The present invention has been made in view of these circumstances, and provides a rubber composition that can give vulcanizates and vulcanized molded articles having better compression set resistance and flex fatigue resistance than conventional rubber compositions.

[0006] According to the present invention, there is provided a rubber composition comprising a chloroprene-based rubber and a crosslinking agent, wherein the chloroprene-based rubber contains a chloroprene-based rubber containing an unsaturated nitrile monomer unit, and the crosslinking agent A has an alkylphenol structure.

[0007]

[0006] Conventionally, there has been a demand for rubber compositions having excellent compression set resistance and flexural fatigue resistance, but it has been difficult to further improve compression set resistance and flexural fatigue resistance. The present inventors have conducted extensive research and found that, in a rubber composition containing a chloroprene-based rubber, by containing a chloroprene-based rubber containing unsaturated nitrile monomer units as the chloroprene-based rubber and using a crosslinking agent having a specific structure, a rubber composition can be obtained that provides a vulcanizate and a vulcanized molded article having even better compression set resistance and flexural fatigue resistance, and have thus completed the present invention.

[0008] Various embodiments of the present invention are exemplified below. The embodiments shown below can be combined with each other. [1] A rubber composition containing a chloroprene-based rubber and a crosslinking agent A, wherein the chloroprene-based rubber contains a chloroprene-based rubber containing an unsaturated nitrile monomer unit, and the crosslinking agent A has an alkylphenol structure. [2] A rubber composition wherein the crosslinking agent A has a chemical structure represented by the following formula (1): (In formula (1), R １ and R ２ are S ｋ , C.H. ２ and CH ２ OCH ２ wherein k is an integer of 1 to 8; and Y １ and Y ２ are each any one selected from hydrogen, halogen, and a hydrocarbon group which may be substituted with halogen, and Z １is a hydrocarbon group which may be substituted with halogen.) [3] The rubber composition according to [1] or [2], wherein the chloroprene-based rubber contains 1 to 25% by mass of the unsaturated nitrile monomer unit relative to 100% by mass of the chloroprene-based rubber. [4] The rubber composition according to any one of [1] to [3], wherein the rubber composition contains a butyl-based rubber. [5] The rubber composition according to [4], wherein the rubber composition contains 0.1 to 50 parts by mass of the chloroprene-based rubber and 50 to 99.9 parts by mass of the butyl-based rubber, relative to 100 parts by mass of the rubber contained in the rubber composition. [6] The rubber composition according to any one of [1] to [5], wherein the rubber composition contains 0.1 to 30 parts by mass of the crosslinking agent A, relative to 100 parts by mass of the rubber contained in the rubber composition. [7] In formula (1), Z １ [8] The rubber composition according to any one of [1] to [7], wherein the crosslinking agent A contains a chemical structure of the following formula (2) at at least one terminal thereof: (In formula (2), X １ is any one selected from OH and halogen, and Y ３ and Y ４ are each any one selected from hydrogen, halogen, and a hydrocarbon group which may be substituted with halogen, and Z ２is a hydrocarbon group which may be substituted with a halogen.) [9] The rubber composition according to any one of [1] to [8], wherein the crosslinking agent A has two or more alkylphenol structures per molecule.

[10] The rubber composition according to any one of [1] to [9], wherein the rubber composition contains 0.1 parts by mass or more of a metal oxide per 100 parts by mass of the rubber contained in the rubber composition.

[11] The rubber composition according to any one of [1] to

[10] , wherein the rubber composition contains 0.1 parts by mass or more of a triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more per 100 parts by mass of the rubber contained in the rubber composition.

[12] The rubber composition according to any one of [1] to

[11] , wherein the crosslinking agent A contains 0.1 to 15% by mass of a halogen element.

[13] The rubber composition according to any one of [1] to

[12] , wherein the rubber composition is for a bladder used at 150 to 220°C.

[14] A vulcanizate of the rubber composition according to any one of [1] to

[13] .

[15] A vulcanized molded article of the rubber composition according to any one of [1] to

[13] .

[0009] The rubber composition according to the present invention can provide a vulcanizate and a vulcanized molded article having excellent compression set resistance and flex fatigue resistance. The vulcanizate and the vulcanized molded article according to the present invention also have excellent compression set resistance and flex fatigue resistance. In addition to known applications (e.g., general industrial power transmission belts and conveyor belts, automotive air springs, anti-vibration rubber, hoses, wipers, immersion products, sealing parts, adhesives, boots, rubber-coated fabrics, and rubber rolls), the vulcanizate and the vulcanized molded article according to the present invention can be suitably used, taking advantage of their properties, as materials for, for example, tire innerliners, tubes, vulcanization bladders, pharmaceutical rubber stoppers, electrical wire coatings, vibration-isolating materials, hoses, linings, capacitor packings, and gaskets. The vulcanizate and the vulcanized molded article according to one embodiment of the present invention can be suitably used for applications requiring particularly excellent compression set resistance and flex fatigue resistance, such as tire innerliners, tubes, vulcanization bladders, and hoses.

[0010] The present invention will be described in detail below by illustrating embodiments of the present invention. The present invention is not limited by these descriptions. The features of the embodiments of the present invention described below can be combined with each other. Furthermore, each feature can be an invention independently.

[0011] 1. Rubber Composition The rubber composition according to the present invention is a rubber composition containing a chloroprene-based rubber and a crosslinking agent, wherein the chloroprene-based rubber contains a chloroprene-based rubber containing unsaturated nitrile monomer units, and the crosslinking agent A has an alkylphenol structure.

[0012] 1.1 Chloroprene-Based Rubber The chloroprene-based rubber according to the present invention refers to a rubber containing a chloroprene-based polymer having chloroprene (2-chloro-1,3-butadiene) as a monomer unit (monomer unit = structural unit). Examples of the chloroprene-based polymer include a chloroprene homopolymer and a chloroprene copolymer (a copolymer of chloroprene and a monomer copolymerizable with chloroprene). The polymer structure of the chloroprene-based polymer is not particularly limited.

[0013] Commercially available 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 of this embodiment.

[0014] The chloroprene rubber according to the present invention contains a chloroprene rubber containing unsaturated nitrile monomer units. The rubber composition according to the present invention can further improve compression set resistance and flex fatigue resistance by containing the chloroprene rubber containing unsaturated nitrile monomer units and a crosslinking agent A having an alkylphenol structure, which will be described later. The mechanism by which the rubber composition according to the present invention can produce a vulcanizate and a vulcanized molded article having further improved compression set resistance and flex fatigue resistance is not clear, but it is thought that the unsaturated nitrile monomer units contained in the chloroprene rubber react with the crosslinking agent A having an alkylphenol structure to form bonds, resulting in the formation of a three-dimensional network in the chloroprene rubber.

[0015] The chloroprene-based rubber according to the present invention may contain one or more chloroprene-based rubbers. The chloroprene-based rubber according to one embodiment of the present invention may contain a chloroprene-based rubber containing one or more unsaturated nitrile monomer units. Furthermore, the chloroprene-based rubber according to one embodiment of the present invention may further contain a chloroprene-based rubber that does not contain one or more unsaturated nitrile monomer units.

[0016] The chloroprene-based rubber (the chloroprene-based rubber containing unsaturated nitrile monomer units and the chloroprene-based rubber not containing unsaturated nitrile monomer units) according to one embodiment of the present invention may also have monomer units derived from a monomer other than the chloroprene monomer and the unsaturated nitrile monomer. The monomer other than the chloroprene monomer and the unsaturated nitrile monomer is not particularly limited as long as it is copolymerizable with the chloroprene monomer, and examples thereof 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-chloro-1,3-butadiene, butadiene, isoprene, ethylene, styrene, sulfur, etc. For example, the chloroprene-based rubber according to one embodiment of the present invention may include 2,3-dichloro-1,3-butadiene monomer units.

[0017] In the chloroprene-based rubber containing unsaturated nitrile monomer units according to one embodiment of the present invention, the content of the unsaturated nitrile monomer units can be 1 to 25% by mass, preferably 1 to 20% by mass, and more preferably 5 to 20% by mass, based on 100% by mass of the chloroprene-based rubber containing unsaturated nitrile monomer units. The content of the unsaturated nitrile monomer units in the chloroprene-based rubber containing unsaturated nitrile monomer units according to one embodiment of the present invention may be, for example, 1, 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, or may be within a range between any two of the values ​​exemplified here. By setting the content of the unsaturated nitrile monomer units in the rubber composition to the above-mentioned upper limit or less, the compression set resistance of the vulcanizate and vulcanized molded article of the rubber composition is further improved. Furthermore, by containing the unsaturated nitrile monomer units in an amount equal to or greater than the lower limit, the oil resistance, elongation at break, elongation at break at high temperatures, heat resistance, compression set resistance and flex fatigue resistance of the vulcanized molded product of the rubber composition are further improved.

[0018] When the chloroprene-based rubber according to one embodiment of the present invention contains two or more chloroprene-based rubbers, the content based on the total amount of unsaturated nitrile monomer units contained in the two or more chloroprene-based rubbers, relative to 100% by mass of the total of the two or more chloroprene-based rubbers contained in the rubber composition, is preferably within the above-mentioned numerical range. That is, the chloroprene-based rubber according to one embodiment of the present invention preferably contains 1 to 25% by mass of unsaturated nitrile monomer units relative to 100% by mass of the chloroprene-based rubber, and the content of the unsaturated nitrile monomer units may be within a range between any two of the above-mentioned numerical values. Furthermore, the chloroprene-based rubber according to one embodiment of the present invention preferably contains 1 to 25% by mass of acrylonitrile monomer units relative to 100% by mass of the chloroprene-based rubber, and the content of the acrylonitrile monomer units may be within a range between any two of the above-mentioned numerical values.

[0019] Examples of unsaturated nitriles include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenylacrylonitrile. The unsaturated nitriles may be used alone or in combination of two or more. The unsaturated nitrile preferably contains acrylonitrile, from the viewpoint of easily obtaining excellent moldability and easily obtaining excellent breaking strength, breaking elongation, hardness, tear strength, and oil resistance in a vulcanized molded product.

[0020] The content of unsaturated nitrile monomer units in chloroprene-based rubber can be calculated from the content of nitrogen atoms in the chloroprene-based rubber. Specifically, the content of nitrogen atoms in 100 mg of chloroprene-based rubber can be measured using an elemental analyzer (Sumigraph 220F, manufactured by Sumika Chemical Analysis Center Co., Ltd.), and the content of structural units derived from unsaturated nitrile monomers can be calculated. Elemental analysis can be performed under the following conditions. For example, the electric furnace temperatures are set to 900°C for the reactor, 600°C for the reduction furnace, 70°C for the column, and 100°C for the detector, and oxygen is flowed at 0.2 mL / min as the combustion gas and 80 mL / min as the carrier gas. A calibration curve can be prepared using aspartic acid (10.52%), which has a known nitrogen content, as a standard substance.

[0021] The chloroprene-based rubber according to one embodiment of the present invention preferably contains 75 to 100 mass% of chloroprene monomer units, and more preferably 80 to 100 mass%, of the chloroprene-based rubber taken as 100 mass%. The content of the chloroprene monomer units in the chloroprene-based rubber may be, for example, 75, 80, 85, 90, 95, 99, or 100 mass%, or may be within a range between any two of the values ​​exemplified here. By setting the content of the chloroprene monomer units within the above numerical range, a rubber composition can be obtained that can give a molded product having an excellent balance of hardness, tensile strength, and cold resistance.

[0022] A chloroprene-based rubber according to one embodiment of the present invention may contain 0 to 20 mass% of monomer units other than chloroprene monomer units and unsaturated nitrile monomer units, when the chloroprene-based rubber is taken as 100 mass%. The content of monomer units other than chloroprene monomer units and unsaturated nitrile monomer units in the chloroprene-based rubber may be, for example, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20 mass%, and may be within a range between any two of the values ​​exemplified here. By adjusting the copolymerization amount of the monomer other than the chloroprene monomer and the unsaturated nitrile monomer within the above range, the effects of copolymerizing these monomers can be achieved without impairing the properties of the resulting rubber composition.

[0023] When the rubber composition according to one embodiment of the present invention contains two or more types of chloroprene-based rubber, it is preferable that the content based on the total amount of each monomer unit contained in the two or more types of chloroprene-based rubber be within the above-mentioned numerical range, relative to 100 mass% in total of the two or more types of chloroprene-based rubber contained in the rubber composition.

[0024] The chloroprene polymer (e.g., chloroprene homopolymer or chloroprene copolymer) contained in the chloroprene rubber according to the present invention may be a sulfur-modified chloroprene polymer, a mercaptan-modified chloroprene polymer, a xanthogen-modified chloroprene polymer, a dithiocarbonate-based chloroprene polymer, a trithiocarbonate-based chloroprene polymer, a carbamate-based chloroprene polymer, or the like.

[0025] 1.2 Method for Producing Chloroprene-Based Rubber The method for producing the chloroprene-based rubber according to the present invention is not particularly limited, but the rubber can be obtained by a production method including an emulsion polymerization step in which raw material monomers containing a chloroprene monomer are emulsion-polymerized. In the emulsion polymerization step according to one embodiment of the present invention, raw material monomers containing a chloroprene monomer are emulsion-polymerized using an appropriate emulsifier, dispersant, catalyst, chain transfer agent, etc., and a polymerization terminator is added when the target final conversion rate is reached, thereby obtaining a latex containing a chloroprene-based polymer containing chloroprene monomer units. Next, unreacted monomers can be removed from the polymerization liquid obtained by the emulsion polymerization step. The method for this removal is not particularly limited, and examples include steam stripping. Thereafter, the pH is adjusted, and the resulting mixture is subjected to conventional processes such as freeze coagulation, water washing, and hot air drying, thereby obtaining a chloroprene-based rubber containing a chloroprene-based polymer.

[0026] The polymerization initiator used in emulsion polymerization is not particularly limited, and any known polymerization initiator generally used in emulsion polymerization of chloroprene can be used. Examples of the polymerization initiator include potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide, and organic peroxides such as t-butyl hydroperoxide.

[0027] The emulsifier used in emulsion polymerization is not particularly limited, and any known emulsifier generally used in emulsion polymerization of chloroprene can be used. Examples of the emulsifier 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 β-naphthalenesulfonic acid (e.g., sodium salt).

[0028] The molecular weight modifier used in emulsion polymerization is not particularly limited, and any known molecular weight modifier commonly used in emulsion polymerization of chloroprene can be used, such as mercaptan compounds, xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds. Xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds are preferably used as molecular weight modifiers for the chloroprene rubber according to one embodiment of the present invention.

[0029] 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. In order to adjust the final conversion rate, a polymerization terminator that terminates the polymerization reaction may be added to terminate the polymerization when the desired conversion rate is reached.

[0030] The polymerization terminator is not particularly limited, and any known polymerization terminator generally used in emulsion polymerization of chloroprene can be used, such as phenothiazine (thiodiphenylamine), 4-t-butylcatechol, and 2,2-methylenebis-4-methyl-6-t-butylphenol.

[0031] The chloroprene rubber according to one embodiment of the present invention can be obtained, for example, by removing unreacted monomers by a steam stripping method, adjusting the pH of the latex, and then performing conventional steps such as freeze coagulation, water washing, and hot air drying.

[0032] Chloroprene rubbers are classified into mercaptan-modified, xanthogen-modified, sulfur-modified, dithiocarbonate-based, trithiocarbonate-based and carbamate-based types depending on the type of molecular weight modifier.

[0033] 1.3 Butyl-Based Rubber The rubber composition according to the present invention may contain a butyl-based rubber. In the present invention, butyl-based rubber refers to a rubber containing a butyl-based polymer containing monomer units derived from isobutylene. That is, the butyl-based rubber contains isobutylene monomer units. Furthermore, the butyl-based rubber according to one embodiment of the present invention may contain isobutylene monomer units and isoprene monomer units, i.e., may contain a copolymer obtained by copolymerizing raw monomers containing isobutylene and isoprene. The butyl-based rubber may contain 0.5 to 10 mol% of isoprene monomer units. The content of isoprene monomer units refers to the proportion (mol%) of isoprene monomer units contained in the butyl-based rubber, where the sum of the number of moles of isobutylene monomer units, the number of moles of isoprene monomer units, and, if present, the number of moles of other monomer units, is 100 mol%.

[0034] The butyl-based rubber according to the present invention may contain one or more types of butyl-based rubber. The butyl-based rubber according to one embodiment of the present invention may contain one or more types selected from regular butyl rubber (non-halogenated butyl rubber) and halogenated butyl rubber. Examples of halogenated butyl rubber include chlorinated butyl rubber and brominated butyl rubber. The halogenated butyl rubber may contain 0.1 to 5.0% by mass of halogen, preferably 0.5 to 3.0% by mass, of halogenated butyl rubber taken as 100% by mass. The halogen content of the halogenated butyl rubber may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0% by mass, and may be within a range between any two of the values ​​exemplified here.

[0035] The butyl rubber according to one embodiment of the present invention preferably contains 75 to 100 mass % of isobutylene monomer units, and more preferably 80 to 100 mass %, of the butyl rubber taken as 100 mass %. The content of chloroprene monomer units in the butyl rubber may be, for example, 75, 80, 85, 90, 95, 99, or 100 mass %, or may be within a range between any two of the values ​​exemplified here.

[0036] 1.4 Other Rubbers The rubber composition according to one embodiment of the present invention may contain rubbers other than chloroprene-based rubber and butyl-based rubber. Examples of other rubbers include natural rubber (NR), hydrogenated acrylonitrile butadiene rubber (H-NBR), acrylonitrile butadiene rubber (NBR), chlorosulfonated polyethylene (CSM), ethylene-propylene-diene rubber (EPDM), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), epoxidized natural rubber (ENR), acrylonitrile butadiene rubber (NBR), styrene-isoprene-butadiene copolymer rubber (SIBR), epichlorohydrin rubber (CO), acrylic rubber (ACM), urethane rubber (U), silicone rubber (Q), fluororubber (FKM), and polysulfide rubber (T). The rubber composition according to one embodiment of the present invention may contain chloroprene-based rubber, butyl-based rubber, and natural rubber.

[0037] 1.5 Amount of Rubber The rubber composition according to the present invention contains 0.1 to 50 parts by mass of chloroprene rubber, based on 100 parts by mass of rubber contained in the rubber composition. The amount of chloroprene rubber is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 25 parts by mass, even more preferably 1 to 15 parts by mass, and can also be 5 to 10 parts by mass. The amount of chloroprene rubber is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0038] The rubber composition according to the present invention preferably contains 50 to 99.9 parts by mass of butyl rubber, based on 100 parts by mass of rubber contained in the rubber composition. The amount of butyl rubber is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5, or 99.9 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0039] The rubber composition according to the present invention preferably contains 70 to 100 parts by mass, and more preferably 90 to 100 parts by mass, of chloroprene-based rubber and butyl-based rubber in total, per 100 parts by mass of rubber contained in the rubber composition. The total content of chloroprene-based rubber and butyl-based rubber is, for example, 70, 75, 80, 85, 90, 95, or 100 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 contain 0 to 30 parts by mass, and may contain 0 to 10 parts by mass, of rubber other than chloroprene-based rubber and butyl-based rubber, per 100 parts by mass of rubber contained in the rubber composition.

[0040] 1.6 Crosslinking Agent A The rubber composition according to the present invention contains crosslinking agent A. Crosslinking agent A has an alkylphenol structure, i.e., crosslinking agent A is a compound having a structure derived from alkylphenol. Crosslinking agent A can have the function of promoting the formation of a three-dimensional network between rubbers. It is preferable that crosslinking agent A itself is incorporated into the three-dimensional network, and more preferable that it forms a crosslinked structure that bonds the rubbers together. As described above, the rubber composition according to the present invention contains a chloroprene rubber containing unsaturated nitrile monomer units and a crosslinking agent A having an alkylphenol structure. It is presumed that the unsaturated nitrile monomer units contained in the chloroprene rubber react with crosslinking agent A having an alkylphenol structure to form bonds, thereby further improving compression set resistance and flex fatigue resistance. Note that crosslinking agent A may not contain a compound having an alkylphenol structure, which is commonly used as an antioxidant.

[0041] The crosslinking agent A preferably has a chemical structure of the following formula (1):

[0042] In formula (1), R １ and R ２ are S ｋ , C.H. ２ and CH ２ OCH ２ k is an integer of 1 to 8.

[0043] Y １and Y ２ Y is any one selected from hydrogen, halogen, and a hydrocarbon group which may be substituted with halogen. １ and Y ２ can be hydrogen or halogen. The hydrocarbon group optionally substituted with a halogen refers to an unsubstituted hydrocarbon group or a hydrocarbon group in which one or more hydrogen atoms contained in the hydrocarbon group have been substituted with a halogen. The number of carbon atoms in the hydrocarbon group can be 2 to 20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or may be within a range between any two of the values ​​exemplified here. The hydrocarbon group can be an alkyl group, a vinyl group, or an aryl group, and can be an alkyl group, and can be a linear or branched alkyl group. The halogen can be any one selected from fluorine, chlorine, bromine, and fluorine atoms, and preferably contains bromine.

[0044] Z １ is a hydrocarbon group which may be substituted with a halogen. １ may contain a hydrocarbon group containing 2 to 20 carbon atoms and optionally substituted with a halogen. The number of carbon atoms in the hydrocarbon group may be 2 to 20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or may be within a range between any two of the values ​​exemplified here. The hydrocarbon group may be an alkyl group, a vinyl group, or an aryl group, and may be an alkyl group, and may be a linear or branched alkyl group. Examples of the alkyl group include an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, and a 1,1-dimethyl-3,3-dimethylpropyl group. The halogen may be any one selected from fluorine, chlorine, bromine and iodine, and preferably includes bromine.

[0045] The crosslinking agent A preferably has a structure capable of forming a bond with rubber at at least one end, and preferably has a structure capable of forming a bond with rubber at both ends. As an example, the crosslinking agent A preferably contains a chemical structure of the following formula (2) at at least one end. The crosslinking agent A preferably contains a structure represented by the following formula (2) at both ends. The structure represented by the following formula (2) is a structure obtained by converting R of the structure represented by formula (1) １ and / or R ２ can be combined with

[0046]

[0047] In formula (2), X １ is any one selected from OH and halogen. The halogen can be any one selected from fluorine, chlorine, bromine, and elements, and preferably includes bromine. ３ and Y ４ are each any one selected from hydrogen, halogen, and hydrocarbon groups which may be substituted with halogen, and specifically, Y １ and Y ２ It can be done in the same way as Z. ２ is a hydrocarbon group which may be substituted with a halogen. ２ may contain a hydrocarbon group containing 2 to 20 carbon atoms and optionally substituted with halogen, specifically Z １ The same can be said.

[0048] Crosslinking agent A can have two or more alkylphenol structures in one molecule. The number of alkylphenol structures in one molecule of crosslinking agent A can be 2 to 10, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and may be within a range between any two of the values ​​exemplified here. The alkylphenol structure can be represented by the following formula (3):

[0049]

[0050] In formula (3), R ３ are S ｋ , C.H. ２ and CH ２ OCH２ and k is an integer of 1 to 8. ５ and Y ６ are each any one selected from hydrogen, halogen, and hydrocarbon groups which may be substituted with halogen, and specifically, Y １ and Y ２ It can be done in the same way as Z. ３ is a hydrocarbon group which may be substituted with a halogen. ３ may contain a hydrocarbon group containing 2 to 20 carbon atoms and optionally substituted with halogen, specifically Z １ The same can be said.

[0051] The crosslinking agent A may have one type of alkylphenol structure or two or more types of alkylphenol structures. When the crosslinking agent A has one type of alkylphenol structure, the crosslinking agent A can be represented by the following formula (4).

[0052]

[0053] In formula (4), R ４ and R ５ are S ｋ , C.H. ２ and CH ２ OCH ２ where k is an integer of 1 to 8. X ２ and X ３ is any one selected from OH and halogen. ２ and X ３ is X １ It can be done in the same way as above. ７ , Y ８ , Y ９ , Y １０ , Y １１ , and Y １２ are each any one selected from hydrogen, halogen, and hydrocarbon groups which may be substituted with halogen, and specifically, Y １ and Y ２ It can be done in the same way as Z. ４ , Z ５ , and Z ６is a hydrocarbon group which may be substituted with a halogen. ４ , Z ５ , and Z ６ may contain a hydrocarbon group containing 2 to 20 carbon atoms and optionally substituted with halogen, specifically Z １ n can be 0 or more, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or can be within a range between any two of the numerical values ​​exemplified here.

[0054] Crosslinking agent A may have two or more alkylphenol structures. When crosslinking agent A has multiple alkylphenol structures, crosslinking agent A can have a structure in which multiple alkylphenol structures are randomly arranged. As an example, when crosslinking agent A has two alkylphenol structures, i.e., when crosslinking agent A has alkylphenol structure X and alkylphenol structure Y, crosslinking agent A can have a structure in which alkylphenol structure X and alkylphenol structure Y are randomly arranged. Note that crosslinking agent A may have a structure other than the structures represented by formula (1) and formula (2), and may have a repeating unit other than an alkylphenol structure. In crosslinking agent A, the content of structures other than the structures represented by formula (1) and formula (2) relative to 100% by mass of crosslinking agent A may be, for example, 0, 10, 20, 30, 40, or 50% by mass, and may be within a range between any two of the numerical values ​​exemplified here. Crosslinking agent A may also be composed only of structures represented by formula (1) and formula (2).

[0055] Crosslinking agent A can be any one selected from the group consisting of a condensate of an alkylphenol and formaldehyde, a condensate of an alkylphenol and a sulfide, and halogenated modifications thereof. Examples of alkylphenols include alkylphenols having an alkyl group with 2 to 20 carbon atoms. The alkyl group may be a linear or branched alkyl group. The sulfide may have 1 to 8 sulfur atoms, for example, 1, 2, 3, 4, 5, 6, 7, or 8, or may be within a range between any two of the values ​​exemplified herein. Crosslinking agent A may contain a halogen. If crosslinking agent A contains a halogen, the halogen concentration of crosslinking agent A is preferably 1 to 10% by mass, more preferably 2 to 7% by mass, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10% by mass, or may be within a range between any two of the values ​​exemplified herein. Crosslinking agent A preferably has a softening point of 120°C or less, more preferably 70 to 100°C. The rubber composition according to one embodiment of the present invention may contain a crosslinking agent other than the crosslinking agent A, a vulcanizing agent, or a vulcanization accelerator.

[0056] 1.7 Vulcanizing Agent and Vulcanization Accelerator The rubber composition according to the present invention may contain a vulcanizing agent. The rubber composition according to the present invention may also contain a vulcanization accelerator. The types of vulcanizing agent and vulcanization accelerator are not particularly limited as long as they do not impair the effects of the present invention. The vulcanizing agent and vulcanization accelerator preferably contribute to the vulcanization of chloroprene-based rubber, more preferably contribute to the vulcanization of butyl-based rubber and / or chloroprene-based rubber, and more preferably contribute to the vulcanization of butyl-based rubber and chloroprene-based rubber.

[0057] One or more vulcanizing agents can be freely selected and used. Examples of vulcanizing agents include sulfur. When the rubber composition according to one embodiment of the present invention contains regular butyl rubber as the butyl rubber, it preferably contains sulfur. The content of the vulcanizing agent can be 0 to 10.0 parts by mass, preferably 0 to 5.0 parts by mass, per 100 parts by mass of rubber contained in the rubber composition. For example, the content may be 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7, 8, 9, or 10.0 parts by mass, or may be within a range between any two of the values ​​exemplified here. The rubber composition according to the present invention may also be free of a vulcanizing agent.

[0058] The rubber composition according to one embodiment of the present invention may contain a vulcanization accelerator. The rubber composition according to one embodiment of the present invention may contain 0 to 10.0 parts by mass of the vulcanization accelerator per 100 parts by mass of the rubber contained in the rubber composition. The content of the vulcanization accelerator is, for example, 0, 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, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0 parts by mass, or may be within a range between any two of the values ​​exemplified here. Note that the rubber composition according to the present invention may not contain a vulcanization accelerator.

[0059] One or more vulcanization accelerators can be freely selected and used, and examples of the vulcanization accelerator include thiuram compounds, 3-methyl-thiazolidine-2-thione, thiadiazole compounds, dithiocarbamate compounds, thiourea compounds, guanidine compounds, xanthogenate compounds, thiazole compounds, and sulfenamide compounds.

[0060] A rubber composition according to one embodiment of the present invention preferably contains at least one selected from a thiourea-based compound, 3-methyl-thiazolidine-2-thione, and a thiadiazole-based compound. A rubber composition according to one embodiment of the present invention preferably contains at least a thiourea-based compound. A rubber composition according to one embodiment of the present invention preferably contains 0.1 to 10.0 parts by mass, and more preferably 0.3 to 5.0 parts by mass, of the thiourea-based compound, 3-methyl-thiazolidine-2-thione, and the thiadiazole-based compound in total per 100 parts by mass of rubber contained in the rubber composition. The total content of the thiourea compound, 3-methyl-thiazolidine-2-thione, and thiadiazole compound is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, and may be within a range between any two of the values ​​exemplified herein. By including one vulcanization accelerator selected from the group consisting of a thiourea compound, 3-methyl-thiazolidine-2-thione, and a thiadiazole compound, and particularly by including the total content within the above-mentioned range, the vulcanization of the chloroprene rubber and the butyl rubber proceeds sufficiently, resulting in a rubber composition capable of producing a vulcanizate and a vulcanized molded article having excellent gas barrier properties, compression set resistance, flex fatigue resistance, and heat resistance.

[0061] The thiourea compound may be a compound having a thiourea structure, such as a compound represented by the following formula:

[0062]

[0063] In the above formula, R １１ ~R １４can each independently represent hydrogen or an organic group, can represent hydrogen or a hydrocarbon group, and the hydrocarbon group can be an alkyl group or an aryl group. Examples of thiourea compounds include ethylene thiourea, diethyl thiourea (N,N'-diethyl thiourea), trimethyl thiourea, diphenyl thiourea (N,N'-diphenyl thiourea), 1,3-trimethylene-2-thiourea, etc.

[0064] 3-Methyl-thiazolidine-2-thione is represented by the following formula:

[0065]

[0066] An example of the thiadiazole compound is di(5-mercapto-1,3,4-thiadiazol-2-yl)disulfide, which is represented by the following formula:

[0067]

[0068] The rubber composition according to one embodiment of the present invention preferably contains one selected from the group consisting of thiuram compounds, thiazole compounds, and sulfenamide compounds. The rubber composition according to one embodiment of the present invention preferably contains 0.1 to 10.0 parts by mass, and more preferably 0.1 to 5.0 parts by mass, of the thiuram compounds, thiazole compounds, and sulfenamide compounds in total, per 100 parts by mass of rubber contained in the rubber composition. The total amount of the thiuram compounds, thiazole compounds, and sulfenamide compounds is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, and may be within a range between any two of the values ​​exemplified herein. By including at least one vulcanization accelerator selected from thiuram compounds, thiazole compounds and sulfenamide compounds, particularly within the above-mentioned numerical range, the rubber composition can give vulcanizates and vulcanized molded articles that are even more excellent in compression set resistance and flex fatigue resistance.

[0069] Examples of thiuram compounds include compounds containing a structure represented by the following formula:

[0070]

[0071] In the above formula, R ２１ , R ２２ , R ２３ , R ２４ can each independently be an organic group, preferably a hydrocarbon group. The hydrocarbon group can be an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 1 to 12 carbon atoms. ２１ and R ２２ , R ２３ and R ２４ may be linked to each other to form a cyclic structure (for example, a cycloalkyl group). n can be an integer of 1 or greater, and can be 1 to 4, preferably 1 or 2, and more preferably 2. Examples of thiuram compounds include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide.

[0072] Examples of sulfenamide compounds include compounds having a sulfenamide structure. Examples of sulfenamide compounds include N-cyclohexyl-2-benzothiazolyl sulfenamide and N-oxydiethylene-2-benzothiazolyl sulfenamide. The sulfenamide compound may be a compound having a sulfenamide structure and a thiazole skeleton.

[0073] Examples of the thiazole compound include compounds having a thiazole skeleton, and those having a benzothiazole skeleton are more preferred. Examples of the thiazole compound include 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, 2-mercaptobenzothiazole zinc salt, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(4'-morpholinodithio)benzothiazole, N-cyclohexylbenzothiazole-2-sulfenamide, N-cyclohexyl-2-benzothiazolyl sulfenamide, and N-oxydiethylene-2-benzothiazolyl sulfenamide. The thiazole compound may be a compound having a thiazole skeleton and a sulfenamide structure.

[0074] The rubber composition according to one embodiment of the present invention may contain vulcanization accelerators other than thiourea-based compounds, 3-methyl-thiazolidine-2-thione, thiadiazole-based compounds, thiuram-based compounds, thiazole-based compounds, and sulfenamide-based compounds. Examples of other vulcanization accelerators include dithiocarbamate-based compounds, guanidine-based compounds, xanthogenate-based compounds, and benzimidazole-based compounds.

[0075] Examples of dithiocarbamate compounds include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, and tellurium diethyldithiocarbamate. Examples of guanidine compounds include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salt of dicatechol borate. Examples of xanthate compounds include zinc butylxanthate and zinc isopropylxanthate. Examples of benzimidazole compounds include compounds having a benzimidazole skeleton. Examples of the benzimidazole compounds include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and zinc salts of 2-mercaptomethylbenzimidazole.

[0076] A rubber composition according to one embodiment of the present invention preferably contains any one selected from thiourea compounds, 3-methyl-thiazolidine-2-thione, and thiadiazole compounds, and any one selected from thiuram compounds, thiazole compounds, and sulfenamide compounds, and it is more preferable that the total content of the thiourea compounds, 3-methyl-thiazolidine-2-thione, and thiadiazole compounds is within the above-mentioned numerical range, and that the total content of the thiuram compounds, thiazole compounds, and sulfenamide compounds is also within the above-mentioned numerical range.

[0077] 1.8 Metal Oxide The rubber composition according to one embodiment of the present invention may contain a metal oxide. The metal oxide may function as a vulcanizing agent and / or an acid acceptor. Examples of the metal oxide include zinc oxide, magnesium oxide, lead oxide, trimelead tetroxide, iron trioxide, titanium dioxide, and calcium oxide. The metal oxide preferably contains at least one of zinc oxide and magnesium oxide, and may contain zinc oxide.

[0078] The rubber composition according to one embodiment of the present invention may contain at least 0.1 parts by mass of a metal oxide per 100 parts by mass of rubber contained in the rubber composition, preferably 0.1 to 15.0 parts by mass, and more preferably 0.5 to 10.0 parts by mass. The metal oxide content may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, or 15.0 parts by mass, or may be within a range between any two of the values ​​exemplified here.

[0079] A rubber composition according to one embodiment of the present invention may contain zinc oxide. Zinc oxide can function as a vulcanizing agent and / or an acid acceptor. The rubber composition according to one embodiment of the present invention may contain 0.1 parts by mass or more of zinc oxide per 100 parts by mass of rubber contained in the rubber composition, preferably 0.1 to 10.0 parts by mass, and more preferably 0.5 to 5.0 parts by mass. The zinc oxide content may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, or may be within a range between any two of the values ​​exemplified here.

[0080] The rubber composition according to one embodiment of the present invention may contain a metal oxide other than zinc oxide. The metal oxide other than zinc oxide can function as an acid acceptor. The rubber composition according to one embodiment of the present invention may contain 0.1 to 10.0 parts by mass, and more preferably 0.5 to 5.0 parts by mass, of the metal oxide other than zinc oxide per 100 parts by mass of rubber contained in the rubber composition. The content of the metal oxide other than zinc oxide is, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0081] 1.9 Plasticizer The rubber composition according to one embodiment of the present invention may contain a plasticizer. The plasticizer is preferably a plasticizer compatible with chloroprene-based rubber, butyl-based rubber, and / or crosslinking agent A, and more preferably a plasticizer compatible with crosslinking agent A. Examples of plasticizers include vegetable oils such as rapeseed oil and castor oil, phthalate-based plasticizers, dioctyl sebacate (DOS), dibutyl sebacate (DBS), dioctyl adipate (DOA), ester-based plasticizers, ether-ester-based plasticizers, thioether-based plasticizers, aromatic oils, naphthenic oils, and paraffinic oils. These may be used alone or in combination of two or more.

[0082] The rubber composition according to one embodiment of the present invention preferably contains a vegetable oil and / or an aromatic oil, and more preferably contains castor oil. The rubber composition according to one embodiment of the present invention preferably contains a triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more. The triacylglycerol may have one or more hydroxy groups, for example, 1, 2, or 3 hydroxy groups, and may be within a range between any two of the numerical values ​​exemplified herein. The triacylglycerol may have a molecular weight of 500 or more, for example, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, or 1500, and may be within a range between any two of the numerical values ​​exemplified herein. An example of a triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more is castor oil, and the main component of castor oil is represented by the following formula:

[0083]

[0084] A rubber composition according to one embodiment of the present invention may contain 0 to 50 parts by mass of a plasticizer per 100 parts by mass of rubber contained in the rubber composition, and preferably 0.1 parts by mass or more. The amount of plasticizer may be, for example, 0, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, or may be within a range between any two of the values ​​exemplified herein. A rubber composition according to one embodiment of the present invention may contain, per 100 parts by mass of rubber contained in the rubber composition, 0.1 parts by mass or more of a triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more. The amount of triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more may be, for example, 0, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, or may be within a range between any two of the values ​​exemplified herein.

[0085] 1.10 Filler The rubber composition according to one embodiment of the present invention may contain a filler. Examples of fillers 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. The rubber composition according to one embodiment of the present invention may contain one or more fillers.

[0086] A rubber composition according to one embodiment of the present invention may contain a total of 20 to 90 parts by mass, preferably 35 to 80 parts by mass, of filler per 100 parts by mass of rubber contained in the rubber composition. The filler content may be, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 parts by mass, or may be within a range between any two of the values ​​exemplified here. By containing the filler content within the above numerical range, the rubber composition according to one embodiment of the present invention can adjust the hardness of the vulcanizate and vulcanized molded article.

[0087] 1.11 Lubricants and Processing Aids The rubber composition according to the present invention may further contain a lubricant and / or a processing aid. Lubricants and processing aids are added primarily to improve processability, such as by making it easier for the rubber composition to be released from rolls, molding dies, extruder screws, etc. Examples of lubricants and processing aids include fatty acids such as stearic acid, paraffin-based processing aids such as polyethylene, fatty acid amides, petrolatum, and factice. The rubber composition according to one embodiment of the present invention may contain one or more types of lubricants and / or processing aids.

[0088] The rubber composition according to the present invention may contain a total of 0 to 15 parts by mass of lubricant and processing aid per 100 parts by mass of rubber contained in the rubber composition, and may also contain 1 to 10 parts by mass. The total content of lubricant and processing aid is, for example, 0, 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 values ​​exemplified here. The rubber composition according to the present invention may also be free of lubricant and / or processing aid.

[0089] 1.12 Others In addition to the above-mentioned components, the rubber composition according to the present invention may further contain components such as organic peroxides, silane coupling agents, co-crosslinking agents (e.g., maleimide-based compounds), stabilizers, flame retardants, and vulcanization retarders, as long as the effects of the present invention are not impaired. Examples of antioxidants and antioxidants include ozone antioxidants, phenolic antioxidants, amine-based antioxidants, acrylate-based antioxidants, waxes, and phosphorus-based antioxidants. Examples of amine-based antioxidants include 4,4'-bis(α,α-dimethylbenzyl)diphenylamine. The rubber composition according to the present invention may contain a total of 0.1 to 10 parts by mass of antioxidants and antioxidants per 100 parts by mass of rubber contained in the rubber composition.

[0090] 2. Method for Producing Rubber Composition A rubber composition according to one embodiment of the present invention can be obtained by kneading rubber and other necessary components at a temperature not higher than the vulcanization temperature. A method for producing a rubber composition according to one embodiment of the present invention can include a mixing step of mixing rubber and other necessary components at a temperature not higher than the vulcanization temperature. Examples of kneading devices include conventionally known kneading devices such as mixers, Banbury mixers, kneader mixers, and open rolls.

[0091] 3. Properties of Rubber Composition The rubber composition according to one embodiment of the present invention preferably has the following properties.

[0092] <Hardness of vulcanized molded article> In the rubber composition according to one embodiment of the present invention, the durometer hardness (Type A) of a vulcanized molded article of the rubber composition, as defined in JIS K 6253, can be 30 to 90, and preferably 40 to 80. The durometer hardness (Type A) of a vulcanized molded article of the rubber composition is, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90, and may be within a range between any two of the numerical values ​​exemplified here.

[0093] <Gas barrier properties of vulcanized molded article> The rubber composition according to one embodiment of the present invention preferably has an air permeability index, as defined in JIS K 6275-1:2022, of 160 or less, relative to an air permeability index of 100 for a vulcanized molded article of a rubber composition containing only butyl-based rubber as the rubber (for example, a vulcanized molded article of the rubber composition according to Comparative Example 1). The air permeability index relative to an air permeability index of 100 for a vulcanized molded article of a rubber composition containing only butyl-based rubber as the rubber is, for example, 90, 100, 110, 120, 130, 140, 150, or 160, and may be within a range between any two of the numerical values ​​exemplified here.

[0094] <Elongation at break of vulcanized molded article> In the rubber composition according to one embodiment of the present invention, it is preferable that the elongation at break of a vulcanized molded article of the rubber composition at 23°C measured in accordance with JIS K 6251 is 200 to 1000%. The elongation at break is, for example, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%, and may be within a range between any two of the numerical values ​​exemplified here.

[0095] <Elongation at break of vulcanized molded product at high temperatures> In a rubber composition according to one embodiment of the present invention, a vulcanized molded product of the rubber composition preferably has an elongation at break of 100 to 1000% at 180°C measured in accordance with JIS K 6251. The elongation at break is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%, and may be within a range between any two of the numerical values ​​exemplified here.

[0096] <Heat Resistance of Vulcanized Molded Article> The rubber composition according to one embodiment of the present invention preferably has an elongation at break of 50 to 1000% when a vulcanized molded article of the rubber composition is heated at 180°C for 48 hours and then measured in accordance with JIS K 6251. The elongation at break after the heat resistance test is, for example, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, or 1000%, and may be within a range between any two of the values ​​exemplified here.

[0097] <Compression set resistance of vulcanized molded article> In a rubber composition according to one embodiment of the present invention, a vulcanized molded article of the rubber composition preferably has a compression set of 62 or less, measured under test conditions of 180°C for 48 hours in accordance with JIS K 6262: 2013. The compression set may be, for example, 20, 30, 40, 50, 55, 60, or 62, or may be within a range between any two of the numerical values ​​exemplified here.

[0098] <Flexural fatigue resistance of vulcanized molded article> The rubber composition according to one embodiment of the present invention preferably has a flexural fatigue test time of 300,000 or more at which cracks occur when a de Mattia flexural fatigue test is performed using a vulcanized molded article of the rubber composition under conditions of a stroke of 58 mm, a speed of 300±10 rpm, and room temperature according to JIS K 6260. The flexural fatigue test time at which cracks occur is, for example, 30, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 10 million times, and may be within a range between any two of the values ​​exemplified here.

[0099] The properties of the rubber composition can be values ​​obtained by forming a vulcanized molded product from the rubber composition under the conditions and by the method described in the Examples and measuring the properties by the method described in the Examples. Furthermore, the properties of the vulcanized molded product of the rubber composition can be controlled by adjusting the type and amount of the rubber composition. For example, the flex fatigue resistance of the vulcanized molded product can be adjusted by adjusting the amount of chloroprene-based rubber, the amount of unsaturated nitrile monomer units contained in the chloroprene-based rubber, and the type and amount of crosslinking agent A.

[0100] 4. Unvulcanized molded body, vulcanized product, and vulcanized molded body The unvulcanized molded body according to one embodiment of the present invention uses the rubber composition according to one embodiment of the present invention, and is a molded body (molded article) of the rubber composition (unvulcanized state) according to one embodiment of the present invention. A method for producing an 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.

[0101] A vulcanizate according to one embodiment of the present invention is a vulcanizate of the rubber composition according to one embodiment of the present invention. A method for producing a 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.

[0102] A vulcanization molded article according to one embodiment of the present invention is a vulcanization molded article of a rubber composition according to one embodiment of the present invention. The vulcanization molded article according to one embodiment of the present invention uses a vulcanizate according to one embodiment of the present invention and is a molded article (molded product) of the vulcanizate according to one embodiment of the present invention. The vulcanization molded article according to one embodiment of the present invention is made of a vulcanizate according to one embodiment of the present invention.

[0103] The vulcanized molded article according to one embodiment of the present invention can be obtained by molding a vulcanizate obtained by vulcanizing the rubber composition (unvulcanized state) according to one embodiment of the present invention, and can also be obtained by vulcanizing a molded article obtained by molding the rubber composition (unvulcanized state) according to one embodiment of the present invention. The vulcanized molded article according to one embodiment of the present invention can be obtained by vulcanizing the rubber composition according to one embodiment of the present invention after molding or during molding. A method for producing a vulcanized molded article according to one embodiment of the present invention comprises a step of molding a vulcanized article according to one embodiment of the present invention, or a step of vulcanizing an unvulcanized molded article according to one embodiment of the present invention.

[0104] The vulcanized molded product according to one embodiment of the present invention preferably has the above-mentioned hardness, gas barrier properties, elongation at break, elongation at break at high temperatures, heat resistance, compression set resistance, and / or flex fatigue resistance.

[0105] The unvulcanized molded article, vulcanized product, and vulcanized molded article according to this embodiment 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 known applications such as rubber parts for automobiles (e.g., automobile seals), hose materials, rubber molds, gaskets, rubber rolls, industrial cables, industrial conveyor belts, sponges, etc. The vulcanized product and vulcanized molded article according to the present invention have excellent compression set resistance and flex fatigue resistance, and the vulcanized product and vulcanized molded article according to one embodiment of the present invention have appropriate hardness and are excellent in gas barrier properties, elongation at break, elongation at break at high temperatures, heat resistance, compression set resistance, and flex fatigue resistance, and can be used as various parts where these properties are particularly required. As an example, the vulcanizate and vulcanization-molded article according to one embodiment of the present invention can be suitably used as materials for tire innerliners, tubes, bladders, pharmaceutical rubber stoppers, electric wire coatings, vibration-proofing materials, hoses, linings, capacitor packing, gaskets, and the like, and can be particularly suitably used for applications requiring particularly excellent gas barrier properties, compression set resistance, and flex fatigue resistance, such as tire innerliners, tubes, vulcanization bladders, and hoses. Furthermore, since the vulcanizate and vulcanization-molded article according to one embodiment of the present invention can maintain excellent gas barrier properties, flex fatigue resistance, compression set resistance, and elongation at break in high-temperature environments, they can be used, for example, for bladders used at 150 to 220°C. Examples of bladders include accumulator bladders, vulcanization bladders for transmission belts, and tire vulcanization bladders. The rubber composition according to one embodiment of the present invention can be used as a rubber composition for tire vulcanization bladders, particularly a rubber composition for tire vulcanization bladders used at 150 to 220°C.

[0106] (Automobile Tire Components, Tire Manufacturing Components) Examples of automobile tire components and tire manufacturing components include tire innerliners, tubes, and vulcanization bladders. A tire innerliner is a rubber sheet that replaces a tube and is attached to the inside of a tubeless tire. Attaching the innerliner prevents air leakage and maintains the tire's air pressure. A vulcanization bladder is a jig used when molding a tire. During tire molding, a tire prototype is placed in a mold, and a bladder is placed in the tire cavity. The bladder is inflated to press the tire against the mold, and the tire is molded and vulcanized by applying pressure and heat. The vulcanizates and vulcanized molded articles obtained from the rubber composition according to the present invention have excellent compression set resistance and flex fatigue resistance. Therefore, it is possible to produce components such as tire innerliners, tubes, and vulcanization bladders that are highly reliable and long-lasting and can withstand repeated deformation while maintaining properties required for these applications, such as gas barrier properties and heat resistance.

[0107] (Automotive Rubber Components) Automotive rubber components include gaskets, oil seals, and packings, which are used in machinery and equipment to prevent leaks of liquids and gases and the intrusion of debris and foreign objects such as rainwater and dust. Specifically, there are gaskets used for fixed applications and oil seals and packings used for moving parts. Gaskets whose sealing parts are fixed with bolts or other fasteners are made of various materials depending on the purpose, as opposed to soft gaskets such as O-rings and rubber sheets. Packings are also used for rotating parts such as pump and motor shafts, moving parts of valves, reciprocating parts such as pistons, coupler connections, and water stop parts of water faucets. The rubber composition of the present invention can improve compression set resistance and flex fatigue resistance. This makes it possible to produce highly reliable, long-lasting automotive rubber components that can withstand repeated deformation while maintaining gas barrier properties and heat resistance, something that was difficult to achieve with conventional rubber compositions.

[0108] (Hose Material) Hose materials are flexible pipes, and specific examples include high- and low-pressure hoses for water supply, oil supply, air supply, steam supply, and hydraulic applications. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of hose materials while maintaining the processability of the unvulcanized product. This makes it possible to produce, for example, highly reliable, long-life hose materials that can withstand repeated deformation while maintaining gas barrier properties and heat resistance, which was difficult to achieve with conventional rubber compositions.

[0109] (Rubber molded products) Examples of rubber molded products include vibration-isolating rubber, vibration-damping materials, and boots. Vibration-isolating rubber and vibration-damping materials are rubbers that prevent the transmission of vibrations. Specific examples include torsional dampers, engine mounts, and muffler hangers for automobiles and various other vehicles that absorb vibrations during engine operation to prevent noise. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of vibration-isolating rubber and vibration-damping materials. This makes it possible to produce vibration-isolating rubber and vibration-damping materials that can be used for long periods of time even in harsh environments, which was difficult to achieve with conventional rubber compositions. Boots are bellows-shaped components whose outer diameter gradually increases from one end to the other. Specific examples include boots for constant velocity joint covers, boots for ball joint covers (dust cover boots), and boots for rack and pinion gears that protect drive parts such as automobile drive systems. The rubber composition of the present invention can improve compression set resistance and flex fatigue resistance. This makes it possible to produce boots that can be used for long periods of time even in harsh environments compared to conventional rubber compositions.

[0110] (Gaskets, etc.) Gaskets, oil seals, and packings are components in machines and equipment that prevent the leakage of liquids and gases and the intrusion of debris and foreign objects such as rainwater and dust into the interior. Specifically, there are gaskets used for fixed applications and oil seals and packings used for moving parts. Gaskets whose sealing parts are fixed with bolts or other fasteners are made of various materials depending on the purpose, as opposed to soft gaskets such as O-rings and rubber sheets. Packings are also used for rotating parts such as pump and motor shafts, moving parts of valves, reciprocating parts such as pistons, coupler connections, and water stop parts of water faucets. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of these components. This makes it possible to produce highly reliable, long-lasting seals that can withstand repeated deformation while maintaining gas barrier properties and heat resistance, something that was difficult to achieve with conventional rubber compositions.

[0111] (Rubber Roll) A rubber roll is manufactured by adhesively coating 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 depending on the required characteristics for 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 conveyed, and is therefore used in a wide range of rubber roll applications. Furthermore, rubber rolls used to convey heavy objects have the problem of deformation under load, and improvements are needed. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of rubber rolls. This makes it possible to manufacture embossing rubber rolls that can be used for long periods of time even in harsh environments, something that was difficult to achieve with conventional rubber compositions.

[0112] (Industrial Cable) Industrial cables are linear components for transmitting electrical or optical signals. They are made by coating a good conductor such as copper or a copper alloy, or an optical fiber, with an insulating coating 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 compression set resistance and flex fatigue resistance of industrial cables. This makes it possible to manufacture highly reliable, long-life industrial cables that can withstand repeated deformation while maintaining gas barrier properties and heat resistance, which were difficult to achieve with conventional rubber compositions.

[0113] (Industrial Conveyor Belts) Industrial conveyor belts are available in rubber, resin, and metal, and are selected to suit a wide variety of uses. Among these, rubber conveyor belts are inexpensive and widely used, but when used in environments where there is a lot of friction and collision with the conveyed materials, they have been prone to damage due to deterioration. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of industrial conveyor belts. This makes it possible to produce industrial conveyor belts that can be used for long periods of time even in harsh environments, which was difficult with conventional rubber compositions.

[0114] (Sponge) Sponges are porous materials with countless fine holes inside, and are specifically used in vibration-damping materials, sponge sealing parts, wetsuits, shoes, etc. The rubber composition of the present invention can improve the compression set resistance and flex fatigue resistance of the sponge. In addition, the use of chloroprene-based rubber can also improve the flame retardancy of the sponge. This makes it possible to produce sponges that can be used for long periods of time even in harsh environments, which was difficult with conventional rubber compositions, and sponges with excellent flame retardancy. Furthermore, the hardness of the resulting sponge can be appropriately adjusted by adjusting the content of the foaming agent, etc.

[0115] Methods for molding the rubber composition (unvulcanized state) and vulcanized product according to this embodiment include press molding, extrusion molding, calendar molding, etc. The temperature for vulcanizing the rubber composition may be appropriately set in accordance with 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 appropriately set depending on the composition of the rubber composition, the shape of the unvulcanized molded product, etc.

[0116] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0117] <Method for Producing Chloroprene-Based Rubber (10% by Mass of Acrylonitrile (AN))> 24 parts by mass of chloroprene (monomer), 24 parts by mass of acrylonitrile (monomer), 0.5 parts by mass of diethylxanthogen disulfide, 200 parts by mass of pure water, 5.00 parts by mass of potassium rosinate (manufactured by Harima Chemicals Co., Ltd.), 0.40 parts by mass of sodium hydroxide, and 2.0 parts by mass of sodium salt of β-naphthalenesulfonic acid formalin condensate (manufactured by Kao Corporation) were added to a 3 L polymerization vessel equipped with a heating / cooling jacket and a stirrer. Next, 0.1 parts by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40°C under a nitrogen gas flow. The chloroprene was added in portions starting 20 seconds after the start of polymerization. The portion-by-portion addition flow rate was adjusted with a solenoid valve based on the change in the heat quantity of the refrigerant over the first 10 seconds of polymerization. Subsequently, the flow rate was readjusted every 10 seconds, thereby carrying out continuous polymerization. When the polymerization rate relative to the total amount of chloroprene and acrylonitrile reached 50%, 0.02 parts by mass of phenothiazine as a polymerization terminator was added to terminate the polymerization. Thereafter, unreacted monomers in the reaction solution were removed under reduced pressure to obtain a chloroprene-based rubber latex containing a chloroprene-acrylonitrile copolymer.

[0118] The above-mentioned polymerization rate [%] of the chloroprene latex was calculated from the dry mass of the air-dried chloroprene latex. Specifically, it was calculated using the following formula (A). In the formula, "solid content concentration" refers to the concentration [% by mass] of the solid content obtained by heating 2 g of a sample of chloroprene latex at 130°C and removing volatile components such as the solvent (water), volatile chemicals, and raw materials. "Total charge amount" refers to the total amount [g] of raw materials, reagents, and solvent (water) charged into the polymerization vessel from the start of polymerization to a certain time. "Evaporation residue" refers to the mass [g] of chemicals and raw materials charged from the start of polymerization to a certain time that do not volatilize under conditions of 130°C and remain as solids together with the polymer. "Monomer charge amount" refers to the sum [g] of the amount of monomer initially charged into the polymerization vessel and the amount of monomer added in portions from the start of polymerization to a certain time. Note that "monomer" here refers to the total amount of chloroprene and acrylonitrile. Conversion rate = {[(total charge amount × solid content concentration / 100) - evaporation residue] / charge amount of monomer} × 100 (A)

[0119] The content of acrylonitrile monomer units contained in the chloroprene-based rubber was calculated from the content of nitrogen atoms in the chloroprene-acrylonitrile copolymer rubber. Specifically, the content of nitrogen atoms in 100 mg of the chloroprene-based rubber was measured using an elemental analyzer (Sumigraph 220F, manufactured by Sumika Chemical Analysis Center, Ltd.), and the content of acrylonitrile monomer units was calculated.

[0120] The above elemental analysis was carried out as follows. The electric furnace temperatures were set to 900°C for the reactor, 600°C for the reduction furnace, 70°C for the column, and 100°C for the detector. 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 prepared using aspartic acid (10.52%), which has a known nitrogen content, as a standard substance. The chloroprene rubber obtained by the above manufacturing method had an acrylonitrile monomer unit content of 10.0% by mass. This was designated as chloroprene rubber AN10%.

[0121] <Method for producing chloroprene-based rubber> The amount of acrylonitrile monomer added in the polymerization step was changed to obtain chloroprene-based rubber AN 5%, in which the acrylonitrile monomer unit content in the chloroprene-based rubber was 5.0 mass%, and chloroprene-based rubber AN 20%, in which the acrylonitrile monomer unit content was 20.0 mass%.

[0122] <Preparation of Rubber Composition> The components shown in Tables 1 to 3 were mixed and kneaded with an 8-inch open roll to obtain rubber compositions of Examples and Comparative Examples.

[0123] The components used to obtain the rubber composition are as follows: (Chloroprene rubber) Acrylonitrile-containing chloroprene rubber: the above-mentioned chloroprene rubber AN 5%, chloroprene rubber AN 10%, chloroprene rubber AN 20% Acrylonitrile-free chloroprene rubber: "M-42" manufactured by Denka Co., Ltd.

[0124] (Butyl rubber) Non-halogenated butyl rubber RIIR268: Regular butyl rubber, manufactured by ENEOS Material Corporation, RIIR268, isoprene 1.7 mol%, Halogenated butyl rubber CIIR1066: Chlorinated butyl rubber, manufactured by ENEOS Material Corporation, CIIR1066, Cl 1.2 mass%, BIIR2244: Brominated butyl rubber, manufactured by ENEOS Material Corporation, BIIR2244, Br 2.0 mass%

[0125] (Crosslinking agent A) Halogenated alkylphenol formaldehyde resin Tackirol 250-III: Brominated alkylphenol formaldehyde resin (brominated modified product of alkyl (C5-10) phenol formaldehyde polycondensate), manufactured by Taoka Chemical Co., Ltd., Tackirol 250-III Non-halogenated alkylphenol formaldehyde resin Tackirol 201: Alkylphenol formaldehyde resin (formaldehyde / 4-nonylphenol / 4-tert-pentylphenol polymer), manufactured by Taoka Chemical Co., Ltd., Tackirol 201, halogen concentration 3.5% by mass PR2500: Formaldehyde / 4-octylphenol polymer, manufactured by Resonac Inc., PR2500 Alkylphenol sulfide resin Tackirol AP: Polycondensate of amylphenol disulfide, manufactured by Taoka Chemical Co., Ltd., Tackirol AP

[0126] (Vulcanization accelerator) Noccela DM: di-2-benzothiazolyl disulfide thiadiazole compound, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noccela DM

[0127] (Plasticizer) Hydroxy group-containing triacylglycerol Castor oil: manufactured by Fukoku Oil Mills Co., Ltd., industrial No. 1 castor oil, the main component has a molecular weight of 933.4 and is represented by the following formula:

[0128]

[0129] (Filler) Carbon black HAF: Asahi #70G, manufactured by Asahi Carbon Co., Ltd.

[0130] (Metal oxide) Zinc oxide type 2: Zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.

[0131] (Lubricant) Stearic acid: Stearic acid 50S, manufactured by New Japan Chemical Co., Ltd.

[0132] The obtained rubber compositions were evaluated by the following methods. The results are shown in Tables 1 to 3. Note that vulcanization did not proceed for the rubber compositions of Comparative Examples 5 and 6, and molded articles suitable for the following evaluations could not be obtained. <Hardness (Type A Durometer)> The obtained rubber compositions were press-vulcanized in accordance with JIS K 6299 at 180°C for 20 minutes to produce sheet-like vulcanized molded articles having a thickness of 2 mm. The durometer hardness (Type A) of the obtained sheet-like vulcanized molded articles was measured using a GS-610 (manufactured by Teclock Corporation) as defined in JIS K 6253.

[0133] <Gas barrier properties> The obtained rubber composition was press-vulcanized at 180°C for 20 minutes in accordance with JIS K 6299 to produce a sheet-like vulcanized molded product having a thickness of 1 mm. The nitrogen permeability of the obtained sheet-like vulcanized molded product was measured at 25°C using a gas permeation tester CT1 (manufactured by Toyo Seiki Seisaku-sho, Ltd.). The nitrogen permeability (based on JIS K 6275-1:2022) was expressed as an index, with the nitrogen permeability of the vulcanized molded product of Comparative Example 1 set at 100. The smaller the index, the lower the nitrogen permeability and the better the gas barrier properties.

[0134] <Elongation at Break> The obtained rubber composition was press-vulcanized at 180°C for 20 minutes to prepare a sheet-like vulcanized molded product having a thickness of 2 mm in accordance with JIS K 6299. The obtained sheet-like vulcanized molded product was molded into a dumbbell-shaped No. 3 test piece, and the elongation at break was measured at 23°C in accordance with JIS K 6251.

[0135] <Elongation at break at high temperature> The obtained rubber composition was press-vulcanized at 180°C for 20 minutes to produce a sheet-like vulcanized molded product having a thickness of 2 mm in accordance with JIS K 6299. The obtained sheet-like vulcanized molded product was molded into a dumbbell-shaped No. 3 test piece, and the elongation at break was measured at 180°C in accordance with JIS K 6251.

[0136] <Heat resistance (change in elongation at break after heating)> The obtained rubber composition was press-vulcanized at 180°C for 20 minutes to produce a sheet-like vulcanized molded product having a thickness of 2 mm in accordance with JIS K 6299. The obtained sheet-like vulcanized molded product was molded into a dumbbell-shaped No. 3 test piece, which was heated at 180°C for 48 hours, and then the elongation at break was measured in accordance with JIS K 6251.

[0137] <Compression Set Resistance> A cylindrical vulcanized molded article having a diameter of 29 mm and a height of 12.5 mm was obtained by press-vulcanizing the article at 180°C for 20 minutes. The compression set was measured under test conditions of 180°C for 48 hours in accordance with JIS K 6262:2013.

[0138] <Flexural Fatigue Resistance> The obtained rubber composition was press-vulcanized at 180°C for 20 minutes to prepare a vulcanized molded article for a De Mattia flexural fatigue test. Using the obtained vulcanized molded article, a De Mattia flexural fatigue test was carried out based on JIS K 6260. The number of flexural tests (unit: 10,000 times) at which cracks occurred was measured under conditions of a stroke of 58 mm, a speed of 300±10 rpm, and room temperature, and the flexural fatigue resistance was evaluated.

[0139]

[0140]

[0141]

Claims

1. A rubber composition comprising a chloroprene rubber and a cross-linking agent A, wherein the chloroprene rubber contains a chloroprene rubber containing an unsaturated nitrile monomer unit, and the cross-linking agent A has an alkylphenol structure.

2. A rubber composition, wherein the crosslinking agent A contains a chemical structure represented by the following formula (1): (In formula (1), R １ and R ２ are S ｋ , C.H. ２ and C.H. ２ OCH ２ wherein k is an integer from 1 to 8; １ and Y ２ each represents one selected from hydrogen, halogen, and a hydrocarbon group which may be substituted with halogen; Z １ is a hydrocarbon group which may be substituted with halogen.

3. A rubber composition according to claim 1 or 2, wherein the chloroprene rubber contains 1 to 25 mass % of the unsaturated nitrile monomer unit relative to 100 mass % of the chloroprene rubber.

4. The rubber composition according to claim 1 or 2, wherein the rubber composition contains a butyl-based rubber.

5. The rubber composition according to claim 4, wherein the rubber composition contains 0.1 to 50 parts by mass of the chloroprene-based rubber and 50 to 99.9 parts by mass of the butyl-based rubber, based on 100 parts by mass of rubber contained in the rubber composition.

6. The rubber composition according to claim 1 or 2, wherein the rubber composition contains 0.1 to 30 parts by mass of the crosslinking agent A when the rubber contained in the rubber composition is taken as 100 parts by mass.

7. In formula (1), Z １ The rubber composition according to claim 2, wherein contains 2 to 20 carbon atoms and contains a hydrocarbon group which may be substituted with a halogen.

8. The rubber composition according to claim 1 or 2, wherein the crosslinking agent A contains a chemical structure represented by the following formula (2) at at least one end: (In formula (2), X １ is any one selected from OH and halogen; Y ３ and Y ４ each represents one selected from hydrogen, halogen, and a hydrocarbon group which may be substituted with halogen; Z ２ is a hydrocarbon group which may be substituted with halogen.

9. The rubber composition according to claim 1 or 2, wherein the crosslinking agent A has two or more alkylphenol structures in one molecule.

10. A rubber composition according to claim 1 or 2, wherein the rubber composition contains 0.1 parts by mass or more of a metal oxide when the rubber contained in the rubber composition is 100 parts by mass.

11. A rubber composition according to claim 1 or claim 2, wherein the rubber composition contains 0.1 parts by mass or more of triacylglycerol having one or more hydroxy groups and a molecular weight of 500 or more when the rubber contained in the rubber composition is 100 parts by mass.

12. The rubber composition according to claim 1 or 2, wherein the crosslinking agent A contains 0.1 to 15 mass % of a halogen element.

13. The rubber composition according to claim 1 or 2, which is for a bladder used at 150 to 220°C.

14. A vulcanizate of the rubber composition according to claim 1 or 2.

15. A vulcanized molded article of the rubber composition according to claim 1 or 2.

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