Rubber compositions, vulcanized products, and vulcanized molded articles

Abstract

Provided is a rubber composition from which a vulcanized product and a vulcanized molded body having excellent wear resistance can be obtained. According to the present invention, provided is a rubber composition containing a chloroprene-based rubber, silica, a silane coupling agent, and a hydrate, wherein the rubber composition contains 5-80 parts by mass of the silica and at least 0.5 parts by mass and less than 20 parts by mass of the hydrate with respect to 100 parts by mass of the chloroprene-based rubber, contains 0.5-15 parts by mass of the silane coupling agent with respect to 100 parts by mass of the silica, and satisfies at least one among the conditions i) and ii) below. Condition i): The rubber composition contains 3-methyl-thiazolidine-2-thione, and contains 0.1-3.0 parts by mass of the 3-methyl-thiazolidine-2-thione with respect to 100 parts by mass of the chloroprene-based rubber. Condition ii): The rubber composition contains compound A and compound B, wherein compound A is at least one selected from among a thiourea-based compound, 3-methyl-thiazolidin-2-thione, and di(5-mercapto-1,3,4-thiadiazol-2-yl)disulfide, compound B is at least one selected from among a thiuram-based compound, a sulfenamide-based compound, a thiazole-based compound, a guanidine-based compound, a benzoimidazole-based compound, N-phenyl-N-(trichloromethyl thio)benzenesulfonamide, and a diazabicyclo undecene-based compound, and the rubber composition contains 0.1-3.0 parts by mass of compound A and 0.01-3.0 parts by mass of compound B with respect to 100 parts by mass of the chloroprene-based rubber.

Description

[Technical Field]

[0001] Chloroprene-based rubbers possess excellent mechanical properties, ozone resistance, and chemical resistance, and these properties are utilized in a wide range of fields, including automotive parts, adhesives, and various industrial rubber components. Furthermore, in recent years, the performance requirements for rubber components have increased significantly, with demands for further improvements in abrasion resistance, for example. [Background technology]

[0002] Patent Document 1 describes copolymers in which the fractions of each monomer constituting the polymer are such that, when the total amount of all monomers is taken as 100% by mass, the copolymer consists of 80-97% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1) and 20-3% by mass of 2,3-dichloro-1,3-butadiene (C-2), or 79.8-96.8% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1), 20-3% by mass of 2,3-dichloro-1,3-butadiene (C-2) and 0.2-17% by mass of monomers copolymerizable with these (C-3). A composition for chloroprene-based vulcanizable rubber is disclosed, comprising 100 parts by mass of a chloroprene-based vulcanizable rubber polymer having a Mooney viscosity (ML1+4 (100℃)) of 100 to 135, 0.5 to 6 parts by mass of an acid acceptor, 0.2 to 3 parts by mass of a lubricant, 1 to 5 parts by mass of an antioxidant, 10 to 120 parts by mass of carbon black, 0.1 to 20 parts by mass of a filler other than carbon black, 2 to 40 parts by mass of a softener, 0.2 to 5 parts by mass of a processing aid, 0.5 to 10 parts by mass of a metal oxide, and 0.5 to 5 parts by mass of a vulcanization accelerator. Furthermore, Patent Document 2 discloses a rubber composition for flame-retardant hoses that contains a rubber component, carbon black, and silica, wherein the rubber component is either chloroprene rubber only, or chloroprene rubber and styrene-butadiene rubber only. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-211345 [Patent Document 2] Japanese Patent Publication No. 2017-019947 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, conventional chloroprene-based rubber compositions had room for improvement in the abrasion resistance of the resulting vulcanized products and vulcanized molded articles. The present invention has been made in view of these circumstances, and provides a rubber composition that can produce vulcanized products and vulcanized molded articles with excellent abrasion resistance. [Means for solving the problem]

[0005] The present invention provides a rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, wherein the rubber composition contains 5 to 80 parts by mass of silica and 0.5 to less than 20 parts by mass of hydrate per 100 parts by mass of chloroprene rubber, and the rubber composition contains 0.5 to 15 parts by mass of the silane coupling agent per 100 parts by mass of silica, and the rubber composition satisfies at least one of the following conditions i) and ii). Condition i) The rubber composition contains 3-methyl-thiazoldin-2-thion, and the rubber composition contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of the chloroprene-based rubber. Condition ii) The rubber composition comprises compound A and compound B, wherein compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds, and the rubber composition contains 0.1 to 3.0 parts by mass of compound A and 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of the chloroprene rubber.

[0006] Conventionally, in rubber compositions containing chloroprene-based rubber, when silica was used as a filler and a vulcanization accelerator supplying sulfur as a crosslinking agent, vulcanization sometimes did not proceed sufficiently. It is presumed that the reason why vulcanization does not proceed sufficiently when silica and a vulcanization accelerator are combined is that the silica surface is covered with silanol groups and becomes acidic, and that vulcanization is inhibited by the adsorption of the vulcanization accelerator onto the silica surface. The inventors conducted diligent research and discovered that by using a certain amount of a specific compound in a chloroprene-based rubber composition containing silica, and / or by using a certain amount of a specific compound A in combination with a specific compound B, it is possible to sufficiently proceed with vulcanization, resulting in a rubber composition that can produce vulcanized products and vulcanized molded articles with excellent abrasion resistance, thus completing the present invention.

[0007] The following are examples of various embodiments of the present invention. The embodiments shown below can be combined with each other. [1] A rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, wherein the rubber composition contains 5 to 80 parts by mass of silica and 0.5 to less than 20 parts by mass of hydrate per 100 parts by mass of chloroprene rubber, the rubber composition contains 0.5 to 15 parts by mass of the silane coupling agent per 100 parts by mass of silica, and the rubber composition satisfies at least one of the following conditions i) and ii). Condition i) The rubber composition contains 3-methyl-thiazoldin-2-thion, and the rubber composition contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of the chloroprene-based rubber. Condition ii) The rubber composition comprises compound A and compound B, wherein compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds, and the rubber composition contains 0.1 to 3.0 parts by mass of compound A and 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of the chloroprene rubber. [2] The rubber composition according to [1], wherein the chloroprene rubber contains unsaturated nitrile monomer units. [3] The rubber composition according to [1] or [2], wherein the silane coupling agent is a silane coupling agent having an amino group in its structure. [4] The rubber composition according to any one of [1] to [3], wherein the hydrate is a hydrate that releases H2O in a temperature range of 100°C to 250°C. [5] The rubber composition according to any one of [1] to [4], wherein the hydrate is at least one hydrate selected from a hydrotalcite compound represented by the following chemical formula (1), a hydrated salt, and a metal hydroxide. [M 2+ 1-x M3+ x (OH)2] x+ [A n- x / n ·mH2O] x- (1) (M 2+ :Mg 2+ 、Mn 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ At least one divalent metal ion M selected from 3+ :Al 3+ 、Fe 3+ 、Cr 3+ 、Co 3+ 、In 3+ At least one trivalent metal ion A selected from n- :OH - 、F - 、Cl - 、Br - 、NO3 - 、CO3 2- 、SO4 2- 、Fe(CN)6 3- 、CH3COO - At least one n-type anion X selected from (0 < X ≤ 0.33) [6] The hydrate is Mg 4.3 Al2(OH) 12.6 CO3·3.5H2O, Mg3ZnAl2(OH) 12 CO3·3H2O, Mg 4.5 Al2(OH) 13 CO3·3.5H2O, Mg 4.5 Al2(OH) 13 CO3, Mg4Al2(OH) 12 CO3·3.5H2O, Mg6Al2(OH) 16 CO3·4H2O, Mg5Al2(OH) 14 CO3·4H2O, Mg3Al2(OH)​​​​​A rubber composition according to any of [1] to [6], wherein the weight is / g. [8] The rubber composition according to any one of [1] to [7], wherein the rubber composition comprises compound A and compound B, and the rubber composition comprises 10 to 100 parts by mass of compound B with respect to 100 parts by mass of compound A. [9] A rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, wherein when the rubber composition is press-vulcanized at 160°C for 40 minutes to obtain a vulcanized molded body, the wear volume ΔV of the vulcanized molded body at 1000 rotations in the Akron abrasion test according to JIS K6264-2 is 50 mm 3 The following is a rubber composition.

[10] The rubber composition according to [9], wherein the durometer hardness (Type A) of the vulcanized molded article as defined in JIS K6253 is 30 to 90.

[11] The rubber composition according to [9] or

[10] , wherein the rubber composition contains 5 to 80 parts by mass of silica and 0.5 to 20 parts by mass of the hydrate per 100 parts by mass of the chloroprene rubber, and the rubber composition contains 0.5 to 15 parts by mass of the silane coupling agent per 100 parts by mass of the silica.

[12] The rubber composition according to any one of [9] to

[11] , comprising 3-methyl-thiazoldin-2-thion, compound A and compound B, wherein compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide and diazabicycloundecene compounds. A vulcanized product of a rubber composition as described in any of

[13] [1] to

[12] . A vulcanized molded article of a rubber composition described in any of

[14] [1] to

[12] . [Effects of the Invention]

[0008] The rubber composition according to the present invention makes it possible to obtain vulcanized products and vulcanized molded articles having excellent abrasion resistance. Furthermore, the obtained vulcanized products and vulcanized molded articles can be suitably used as materials for general industrial power transmission belts and conveyor belts, automobile air springs, vibration-damping rubber, hoses, wipers, immersion products, sealing parts, adhesives, boots, rubberized fabrics, rubber rolls, etc., taking advantage of their properties. The vulcanized products and vulcanized molded articles according to one embodiment of the present invention can be used in particular as components that require abrasion resistance. As an example, the vulcanized products and vulcanized molded articles according to one embodiment of the present invention can be suitably used as rubber rolls that require abrasion resistance, for example, rubber rolls for embossing. [Modes for carrying out the invention]

[0009] The present invention will be described in detail below with reference to embodiments of the present invention. The present invention is not limited in any way by these descriptions. The features of the embodiments of the present invention shown below can be combined with each other. Furthermore, each feature constitutes an invention independently.

[0010] <First Perspective> 1. Rubber composition The rubber composition according to the present invention comprises chloroprene rubber, silica, a silane coupling agent, and a hydrate, and further comprises 3-methyl-thiazoldin-2-thion, and / or compounds A and B.

[0011] 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 chloroprene-based polymers include chloroprene homopolymers and chloroprene copolymers (polymers of chloroprene and monomers copolymerizable with chloroprene). The polymer structure of the chloroprene-based polymer is not particularly limited.

[0012] Commercially available 2-chloro-1,3-butadiene may contain small amounts of 1-chloro-1,3-butadiene as an impurity. Such 2-chloro-1,3-butadiene containing small amounts of 1-chloro-1,3-butadiene can also be used as the chloroprene monomer in this embodiment.

[0013] The chloroprene-based rubber according to one embodiment of the present invention preferably contains unsaturated nitrile monomer units. The chloroprene-based rubber according to one embodiment of the present invention preferably has an unsaturated nitrile monomer unit content of 25% by mass or less, more preferably less than 25% by mass, and even more preferably 1% by mass or more and less than 25% by mass, when the rubber is considered as 100% by mass. The unsaturated nitrile monomer unit content in the chloroprene-based rubber according to one embodiment of the present invention is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24% by mass, less than 25% by mass, and 25% by mass or less, and may be within the range of any two of the values ​​exemplified here. By setting the unsaturated nitrile monomer unit content in the rubber composition to 25% by mass or less, the water resistance and cold resistance of the vulcanized product and vulcanized molded article of the rubber composition are further improved. Furthermore, by ensuring that the content of unsaturated nitrile monomer units is 1% by mass or more, the resulting rubber composition will have sufficient oil resistance.

[0014] Examples of unsaturated nitriles include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenylacrylonitrile. Unsaturated nitriles can be used individually or in combination of two or more. From the viewpoint of easily obtaining excellent moldability and easily obtaining excellent tensile strength, elongation at break, hardness, tear strength, and oil resistance in vulcanized molded articles, it is preferable that the unsaturated nitrile includes acrylonitrile.

[0015] The content of unsaturated nitrile monomer units in chloroprene rubber can be calculated from the nitrogen atom content in the chloroprene rubber. Specifically, the nitrogen atom content in 100 mg of chloroprene rubber can be measured using an elemental analyzer (Sumigraph 220F: manufactured by Sumika 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 temperature is set to 900°C for the reactor, 600°C for the reduction furnace, 70°C for the column, and 100°C for the detector, with 0.2 mL / min of oxygen as the combustion gas and 80 mL / min of helium as the carrier gas flowing. A calibration curve can be created using aspartic acid (10.52%), which has a known nitrogen content, as a standard substance.

[0016] The chloroprene-based rubber according to one embodiment of the present invention preferably contains 60 to 100% by mass of chloroprene monomer units when the rubber is considered as 100% by mass. The content of chloroprene monomer units in the rubber may be, for example, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. By setting the content of chloroprene monomer units within the above numerical range, a rubber composition can be obtained that yields a molded article with an excellent balance of hardness, tensile strength, and cold resistance.

[0017] The chloroprene-based rubber according to one embodiment of the present invention may also have monomer units other than chloroprene monomers and unsaturated nitrile monomers. Examples of monomer units other than chloroprene monomers are not particularly limited as long as they are copolymerizable with chloroprene monomers or chloroprene monomers and unsaturated nitrile monomers, but include (meth)acrylic acid esters ((meth)acrylate, (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.

[0018] The chloroprene-based rubber according to one embodiment of the present invention may contain 0 to 20% by mass of monomer units other than chloroprene monomers and unsaturated nitrile monomers when the rubber is considered as 100% by mass. The content of monomer units other than chloroprene monomers and unsaturated nitrile monomers in the rubber may be, for example, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% by mass, and may be within the range of any two of the values ​​exemplified here. By adjusting the copolymerization amount of monomers other than chloroprene monomers and unsaturated nitrile monomers to this range, the effects of copolymerizing these monomers can be expressed without impairing the properties of the resulting rubber composition. Furthermore, the chloroprene-based rubber according to one embodiment of the present invention may consist only of chloroprene monomer units and unsaturated nitrile monomer units, or it may consist only of chloroprene monomer units.

[0019] The rubber composition according to the present invention can use chloroprene-based rubber alone or in combination of two or more types. In the case where the rubber composition according to one embodiment of the present invention contains two or more types of chloroprene rubber, it is preferable that the total content of unsaturated nitrile monomer units contained in the two or more types of chloroprene rubber contained in the rubber composition is 25% by mass or less.

[0020] The chloroprene polymer (chloroprene homopolymer, chloroprene copolymer, etc.) contained in the chloroprene rubber according to the present invention may be sulfur-modified chloroprene polymer, mercaptan-modified chloroprene polymer, xanthogene-modified chloroprene polymer, dithiocarbonate-based chloroprene polymer, trithiocarbonate-based chloroprene polymer, carbamate-based chloroprene polymer, etc.

[0021] The weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (polydispersity of molecular weight, Mw / Mn) of chloroprene rubber may be within the following ranges, from the viewpoint of easily obtaining a good balance of excellent hardness, tensile strength, and cold resistance.

[0022] The weight-average molecular weight of chloroprene rubber is 10 × 10 3 g / mol or more, 50×10 3 g / mol or more, 100×10 3 g / mol or more, 300×10 3 g / mol or more, 400×10 3 g / mol or more, or 450 × 10 3 It may be greater than or equal to g / mol. The weight-average molecular weight of chloroprene rubber is 5000 × 10 3 g / mol or less, 3000×10 3 g / mol or less, 2000×10 3 g / mol or less, 1000×10 3 g / mol or less, 800×10 3 g / mol or less, or 500 × 10 3 From these perspectives, the weight-average molecular weight of chloroprene rubber is 10 × 10 3 ~5000 x 10 3 g / mol, 100 × 10 3 ~2000×10 3g / mol, or 300 × 10⁻⁶ 3 ~1000×10 3 It can be expressed as g / mol.

[0023] The number-average molecular weight of chloroprene rubber is 1 × 10⁻⁶ 3 g / mol or more, 5×10 3 g / mol or more, 10×10 3 g / mol or more, 50×10 3 g / mol or more, 100×10 3 g / mol or more, or 130 × 10 3 It may be g / mol or more. The number-average molecular weight of chloroprene rubber is 1000 × 10 3 g / mol or less, 800×10 3 g / mol or less, 500×10 3 g / mol or less, 300×10 3 g / mol or less, 200×10 3 g / mol or less, or 150 × 10 3 It may be less than or equal to g / mol. From these perspectives, the number-average molecular weight of chloroprene rubber is 1 × 10⁻⁶. 3 ~1000×10 3 g / mol, 10 × 10 3 ~500×10 3 g / mol, or 50 × 10 3 ~300×10 3 It can be expressed as g / mol.

[0024] The molecular weight distribution of chloroprene rubber may be 1.0 or higher, 1.5 or higher, 2.0 or higher, 2.5 or higher, 3.0 or higher, 3.2 or higher, or 3.4 or higher. The molecular weight distribution of chloroprene rubber may be 10 or lower, 8.0 or lower, 5.0 or lower, 4.0 or lower, 3.8 or lower, 3.5 or lower, or 3.4 or lower. From these viewpoints, the molecular weight distribution of chloroprene rubber may be 1.0 to 10, 2.0 to 5.0, or 2.5 to 4.0.

[0025] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of chloroprene rubber can be obtained by measuring them using gel permeation chromatography (GPC) and converting them to polystyrene equivalents. Specifically, they can be measured by the method described in the examples.

[0026] 1.2 Method for manufacturing chloroprene rubber The method for producing chloroprene rubber according to the present invention is not particularly limited, but it can be obtained by a production method that includes an emulsion polymerization step in which raw material monomers containing chloroprene monomers are emulsion polymerized. In the emulsion polymerization process according to one embodiment of the present invention, a chloroprene monomer, or a monomer containing a chloroprene monomer and an unsaturated nitrile monomer, is emulsion polymerized using an emulsifier, dispersant, catalyst, chain transfer agent, etc. as appropriate, and when the desired final conversion rate is reached, a polymerization termination agent is added to obtain a latex containing a chloroprene polymer containing chloroprene monomer units. Next, unreacted monomers can be removed from the polymerization solution obtained in the emulsion polymerization process. The method for this is not particularly limited, and for example, a steam stripping method can be used. After that, the pH is adjusted, and a chloroprene rubber containing a chloroprene polymer can be obtained by going through processes such as conventional freeze-solidification, water washing, and hot air drying.

[0027] There are no particular restrictions on the polymerization initiator used in emulsion polymerization; known polymerization initiators commonly used in the emulsion polymerization of chloroprene can be used. Examples of polymerization initiators include potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide, and organic peroxides such as t-butyl hydroperoxide.

[0028] There are no particular restrictions on the emulsifier used in emulsion polymerization, and any known emulsifier commonly used in the emulsion polymerization of chloroprene can be used. Examples of emulsifiers include alkali metal salts of saturated or unsaturated fatty acids having 6 to 22 carbon atoms, alkali metal salts of rosinic acid or disproportionated rosinic acid (e.g., potassium rosinate), and alkali metal salts of formalin condensates of β-naphthalenesulfonic acid (e.g., sodium salt).

[0029] There are no particular restrictions on the molecular weight modifier used in emulsion polymerization, and known molecular weight modifiers commonly used in the emulsion polymerization of chloroprene can be used, such as mercaptan compounds, xanthogene compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds. In one embodiment of the present invention, xanthogene compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds can be suitably used as molecular weight modifiers for chloroprene-based rubber.

[0030] 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. Polymerization may be carried out so that the final conversion rate of the monomer falls within the range of 40 to 95% by mass. To adjust the final conversion rate, a polymerization inhibitor can be added to stop the polymerization reaction when the desired conversion rate is reached.

[0031] There are no particular restrictions on the polymerization inhibitor; any known polymerization inhibitor commonly used in the emulsion polymerization of chloroprene can be used. Examples of polymerization inhibitors include phenothiazine (thiodiphenylamine), 4-t-butylcatechol, and 2,2-methylenebis-4-methyl-6-t-butylphenol.

[0032] A chloroprene-based rubber according to one embodiment of the present invention can be obtained, for example, by removing unreacted monomers by steam stripping, adjusting the pH of the latex, and then following conventional freeze-solidification, water washing, and hot-air drying processes.

[0033] Chloroprene-based rubbers are classified into mercaptan-modified type, xanthogene-modified type, sulfur-modified type, dithiocarbonate type, trithiocarbonate type, and carbamate type, depending on the type of molecular weight modifier used.

[0034] 1.3 3-Methyl-thiazoldin-2-thion, Compound A and Compound B The rubber composition according to the present invention satisfies at least one of the following conditions i) and ii). Condition i) The rubber composition contains 3-methyl-thiazoldin-2-thion, and contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of the chloroprene rubber. Condition ii) The rubber composition comprises compound A and compound B, wherein compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds, and the rubber composition contains 0.1 to 3.0 parts by mass of compound A and 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of the chloroprene rubber.

[0035] Conventionally, in rubber compositions containing chloroprene-based rubber, when silica as a filler and a vulcanization accelerator supplying sulfur as a crosslinking agent were used in combination, vulcanization sometimes did not proceed sufficiently. Here, the reason why vulcanization does not proceed sufficiently when silica and a vulcanization accelerator are combined is presumed to be that the silica surface is covered with silanol groups and becomes acidic, and that vulcanization is inhibited by the adsorption of the vulcanization accelerator onto the silica surface. The inventors of the present invention conducted diligent research and found that by satisfying the above conditions i) and / or ii) in a chloroprene-based rubber composition containing silica, it is possible to obtain a rubber composition in which vulcanization can proceed sufficiently and vulcanized products and vulcanized molded articles with excellent abrasion resistance can be obtained, leading to the completion of the present invention. According to one embodiment of the present invention, since vulcanization proceeds sufficiently, it is possible to obtain vulcanized products and vulcanized molded articles with excellent abrasion resistance and tensile properties such as tensile strength at break and elongation at break, and / or compression set resistance. Furthermore, according to the present invention, the hardness of the resulting vulcanized product and vulcanized molded article can be freely adjusted by adjusting the type and amount of rubber composition, particularly the amount of filler such as silica, thereby obtaining vulcanized products and vulcanized molded articles that have various hardnesses according to the application and usage environment, while also having excellent abrasion resistance, tensile properties, and / or compression set resistance. For example, it is also possible to design vulcanized products and vulcanized molded articles that have relatively low hardness and excellent abrasion resistance, tensile properties, and / or compression set resistance.

[0036] If the rubber composition according to the present invention satisfies condition i), the rubber composition contains 3-methyl-thiazoldin-2-thion (formula shown below). In this case, the rubber composition contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of chloroprene rubber. The content of 3-methyl-thiazoldin-2-thion per 100 parts by mass of chloroprene rubber is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0037] [ka]

[0038] Furthermore, if the rubber composition contains 3-methyl-thiazoldin-2-thione, the rubber composition does not necessarily have to contain compound B described below. For example, it may contain 3.0 parts by mass or less per 100 parts by mass of chloroprene rubber.

[0039] If the rubber composition according to the present invention satisfies condition ii), the rubber composition comprises compound A and compound B. Compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide.

[0040] Examples of thiourea compounds include compounds having a thiourea structure. Examples of thiourea compounds include compounds represented by the following formula.

[0041] [ka]

[0042] In the above formula, R 11~R 14 Each of these can independently be hydrogen or an organic group, or hydrogen or a hydrocarbon group, and the hydrocarbon group can be an alkyl group or an aryl group. Examples of thiourea compounds include ethylenethiourea, diethylthiourea (N,N'-diethylthiourea), trimethylthiourea, diphenylthiourea (N,N'-diphenylthiourea), and 1,3-trimethylene-2-thiourea.

[0043] Di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide is represented by the following formula.

[0044] [ka]

[0045] Compound B is at least one selected from thiuram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds (excluding the compounds listed as Compound A). Preferably, Compound B is at least one selected from thiuram compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds (excluding the compounds listed as Compound A).

[0046] Examples of thiram compounds include compounds containing one or more structures represented by the following formula.

[0047] [ka]

[0048] In the above formula, R 21 , R 22 , R 23 , R 24may each independently be an organic group, preferably a hydrocarbon group. The hydrocarbon group may be an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 1 to 12 carbon atoms. R 21 and R 22 , R 23 and R 24 may each be linked to form a cyclic structure (e.g., a cycloalkyl group). n can be an integer of 1 or more, can be 1 to 4, is 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, dipentamethylenethiuram tetrasulfide, and the like.

[0049] Examples of sulfenamide compounds include compounds having a sulfenamide structure. Examples of sulfenamide compounds include N-cyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, and the like. The sulfenamide compound may be a compound having a sulfenamide structure and a thiazole skeleton.

[0050] Examples of thiazole compounds include compounds having a thiazole skeleton (excluding the compounds listed as compound A), and more preferably having a benzothiazole skeleton. Examples of thiazole compounds include 2-mercaptobenzothiazole, di-2-benzothiazolyldisulfide, zinc salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(4'-morpholinodithio)benzothiazole, N-cyclohexylbenzothiazole-2-sulfenamide, N-cyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, and the like. The thiazole compound may be a compound having a thiazole skeleton and a sulfenamide structure.

[0051] Examples of guanidine compounds include compounds having a guanidine skeleton. Examples of guanidine compounds include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, and di-o-tolylguanidine salts of dicatecholborate.

[0052] Examples of benzimidazole compounds include compounds having a benzimidazole skeleton. Examples of benzimidazole compounds include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and zinc salts of 2-mercaptomethylbenzimidazole.

[0053] N-phenyl-N-(trichloromethylthio)benzenesulfonamide is represented by the following formula. [ka]

[0054] Examples of diazabicycloundecene compounds include compounds having a diazabicycloundecene skeleton. An example of a diazabicycloundecene compound is 1,8-diazabicyclo[5.4.0]undecene-7.

[0055] The rubber composition contains 0.1 to 3.0 parts by mass of compound A per 100 parts by mass of chloroprene rubber. The content of compound A per 100 parts by mass of chloroprene rubber is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0056] The rubber composition contains 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of chloroprene rubber. The content of compound B per 100 parts by mass of chloroprene rubber is, for example, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0057] When the rubber composition contains compound A and compound B, it is preferable that the rubber composition contains 10 to 100 parts by mass of compound B per 100 parts by mass of compound A. The content of compound B per 100 parts by mass of compound A may be, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0058] Compound A can be any of the above-mentioned compounds used individually or in combination of two or more. Compound B can also be any of the above-mentioned compounds used individually or in combination of two or more. When the rubber composition contains 3-methyl-thiazoldin-2-thion and compound B, it is preferable that the rubber composition contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion and 0.1 to 3.0 parts by mass of compound B. When the rubber composition contains compound A and compound B other than 3-methyl-thiazoldin-2-thion, it is preferable that the total content of compound A including 3-methyl-thiazoldin-2-thion is 0.1 to 3.0 parts by mass, and it is more preferable that the content of compound B is 0.1 to 3.0 parts by mass.

[0059] The rubber composition may also include compounds other than 3-methyl-thiazoldin-2-thion, compound A, and compound B, which can be used as vulcanizing agents and / or vulcanization accelerators for chloroprene rubber. The content of vulcanizing agents and vulcanization accelerators other than 3-methyl-thiazoldin-2-thion, compound A, and compound B, per 100 parts by mass of chloroprene rubber, can be, for example, 0.01, 0.02, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range between any two of the values ​​exemplified here. The rubber composition according to one embodiment of the present invention may also not contain vulcanizing agents and vulcanization accelerators other than 3-methyl-thiazoldin-2-thion, compound A, and compound B. Other examples of vulcanizing agents and vulcanization accelerators besides 3-methyl-thiazoldin-2-thion, compound A, and compound B include sulfur, dithiocarbamate-based vulcanization accelerators, and xanthogenic acid-based vulcanization accelerators.

[0060] The rubber composition according to one embodiment of the present invention may also contain an organic peroxide. When an organic peroxide is used, the content of the organic peroxide per 100 parts by mass of chloroprene rubber may be 3.0 parts by mass or less. The amount of organic peroxide added may be, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here. The rubber composition according to one embodiment of the present invention may not contain an organic peroxide.

[0061] 1.4 Silica Silica is added to the rubber composition as a filler, and its type is not particularly limited. Examples of silica that can be used include wet silica (hydrated silica), dry silica (anhydrous silica), and colloidal silica, with wet silica being preferred.

[0062] From the perspective of processability and the resulting physical properties, silica has a BET specific surface area of ​​50-300 m².2 It is preferable to use a product with a specific surface area of ​​ / g. The BET specific surface area can be, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300m². 2 The value is / g, and may be within the range of any two of the values ​​exemplified here.

[0063] The amount of silica added is 5 to 80 parts by mass per 100 parts by mass of chloroprene rubber. The silica content per 100 parts by mass of chloroprene rubber can be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80, and may be within the range of any two of the values ​​exemplified here.

[0064] A rubber composition according to one embodiment of the present invention may contain fillers other than silica. Examples of fillers other than silica 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, fume black, thermal carbon such as FT and MT; acetylene black, Ketjen black; clay; talc; and calcium carbonate.

[0065] The rubber composition according to one embodiment of the present invention preferably contains 50% by mass or more silica when the filler contained in the rubber composition is considered to be 100% by mass. The silica content when the filler contained in the rubber composition is considered to be 100% by mass may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. The rubber composition according to one embodiment of the present invention may not contain any fillers other than silica.

[0066] 1.5 Silane coupling agents A rubber composition according to one embodiment of the present invention contains a silane coupling agent. The silane coupling agent in the rubber composition according to one embodiment of the present invention is not particularly limited, and any commercially available rubber composition can be used. For example, there are 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. From the viewpoint of good reactivity with chloroprene rubber, it is preferable to include a silane coupling agent having an amino group in its structure, i.e., an amino coupling agent.

[0067] Specifically, silane coupling agents include 3-methacryloxypropyltrimethoxysilane, bis-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-trimethoxylylpropyl)tetrasulfide, bis-(3-methyldimethoxysilylpropyl)tetrasulfide, bis-(2-triethoxysilylethyl)tetrasulfide, bis-(3-triethoxysilylpropyl)disulfide, bis-(3-trimethoxysilylpropyl)disulfide, bis -(3-triethoxysilylpropyl)trisulfide, 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoyl Thiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-trimethoxysilylpropyl methacryloyl monosulfide, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, isobutyltrimethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, hexyltrimethoxysilane, octa Examples include decylmethyldimethoxysilane, octadecyltrimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, triphenylchlorosilane, heptadecafluorodecylmethyldichlorosilane, heptadecafluorodecyltrichlorosilane, and triethylchlorosilane, with 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane being preferred.

[0068] 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 the range of any two of the values ​​exemplified herein. These can be used individually or in combination of two or more. By containing the above-mentioned silane coupling agent and setting the content of the silane coupling agent within the above numerical range, it is possible to improve the dispersibility of silica filler in the rubber, the reinforcing effect between the rubber and silica filler, and suppress the occurrence of scorch.

[0069] 1.6 Hydrate The hydrate preferably has a structure in which H2O is released, for example, during kneading and vulcanization. The hydrate is more preferably a hydrate that releases H2O in the temperature range of 100°C to 250°C, and even more preferably a hydrate that releases H2O in the temperature range of 100°C to 150°C. Thereby, the reaction between the silane coupling agent and silica is promoted, and good physical properties and vulcanization rate can be obtained.

[0070] The hydrate is not particularly limited, and those used in commercially available rubber compositions can be used. For example, hydrotalcite compounds represented by the following chemical formula (1), hydrous salts, and metal hydroxides can be used. [M 2+ 1-x M 3+ x (OH)2] x+ [A n-x / n ·mH2O] x- (1)

[0071] In the above formula (1), M 2+ : Mg 2+ , Zn 2+ At least one divalent metal ion selected from M 3+ : Al 3+ , Fe 3+ At least one trivalent metal ion selected from A n- : CO3 2- , Cl ― , NO3 2- At least one n-type anion selected from X: 0 < X ≤ 0.33 Can be set as.

[0072] [[ID=5б]]As the hydrotalcite compound, Mg 4.3 Al2(OH) 12.6 CO3·3.5H2O, Mg3ZnAl2(OH) 12 CO3·3H2O, Mg 4.5 Al2(OH) 13 CO3·3.5H2O, Mg 4.5 Al2(OH)13 CO3, Mg4Al2(OH) 12 CO3·3.5H2O, Mg6Al2(OH) 16 CO3·4H2O, Mg5Al2(OH) 14 CO3·4H2O, Mg3Al2(OH) 10 Examples include CO3·1,7H2O, and particularly preferably Mg 4.3 Al2(OH) 12.6 CO3·3.5H2O, Mg3ZnAl2(OH) 12 It is CO3·3H2O.

[0073] Examples of hydrated salts include Al2O3·3H2O, Al2O3·H2O, Na2SO4·10H2O, CaSO4·2H2O, NaHCO3·Na2CO3·2H2O, and MgSO4·7H2O, with Al2O3·3H2O being particularly preferred.

[0074] Examples of hydroxides include Ca(OH)2, Al(OH)3, Mg(OH)2, and Zn(OH)2, with Mg(OH)2 being particularly preferred.

[0075] The hydrate content is 0.5 parts by mass or more and less than 20 parts by mass, preferably 1 part by mass or more and less than 20 parts by mass, and more preferably 4 to 10 parts by mass, per 100 parts by mass of chloroprene rubber. The amount of hydrate added can be, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 parts by mass or less than 20 parts by mass, and may be within the range of any two of the values ​​exemplified here. By using hydrate within this range, a rubber composition with excellent abrasion resistance can be obtained.

[0076] 1.7 Acid absorbers A rubber composition according to one embodiment of the present invention may contain an acid acceptor. Examples of acid acceptors include metal oxides, such as zinc oxide, magnesium oxide, lead oxide, trilead tetroxide, iron oxide, titanium dioxide, and calcium oxide. The metal oxide preferably contains zinc oxide, and more preferably zinc oxide.

[0077] 1.8 Plasticizers There are no particular restrictions on the plasticizer as long as it is compatible with chloroprene rubber, but examples include vegetable oils such as rapeseed oil, phthalate plasticizers, DOS (dioctyl sebacate), DBS (dibutyl sebacate), DOA (dioctyl adipate), ester plasticizers, ether / ester plasticizers, thioether plasticizers, aromatic oils, naphthenic oils, etc. These can be used individually or in combination of two or more. The amount of plasticizer added can be 0 to 50 parts by mass per 100 parts by mass of chloroprene rubber contained in the rubber composition, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0078] 1.9 Lubricants and processing aids The rubber composition according to the present invention may further contain a lubricant and / or processing aid. The lubricant and processing aid are added mainly to improve processability, such as making it easier for the rubber composition to peel off rolls, molds, 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 Factis. These can be used individually or in combination of two or more. The rubber composition according to the present invention may contain 1 to 15 parts by mass of lubricants and processing aids per 100 parts by mass of chloroprene rubber contained in the rubber composition, and may also be 1 to 10 parts by mass. The content of lubricants and processing aids may be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0079] 1.10 Other The rubber composition according to the present invention may further contain, in addition to the above-mentioned components, components such as antioxidants, antioxidants, flame retardants, and vulcanization retardants, to the extent that they do not impair the effects of the present invention. Examples of antioxidants and antioxidants include ozone antioxidants, phenolic antioxidants, amine antioxidants, acrylate antioxidants, waxes, and phosphorus antioxidants. An example of an amine antioxidant is 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 chloroprene rubber contained in the rubber composition.

[0080] 2. Method for producing rubber composition A rubber composition according to one embodiment of the present invention is obtained by kneading chloroprene rubber and other necessary components at a temperature below the vulcanization temperature. Examples of kneading equipment for mixing the component materials include conventionally known kneading devices such as mixers, Banbury mixers, kneader mixers, and open rolls.

[0081] 3. Properties of rubber compositions The rubber composition according to the ACT preferably has the following properties.

[0082] <Hardness of vulcanized molded products> A rubber composition according to one embodiment of the present invention can adjust the durometer hardness (Type A) of a vulcanized molded article of the rubber composition to 30 to 90 as defined in JIS K 6253. The durometer hardness (Type A) of a vulcanized molded article of the rubber composition can be, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90, and may be within the range of any two of the values ​​exemplified here. The durometer hardness (Type A) of a vulcanized molded article of the rubber composition can be controlled by adjusting the type and amount of compounding in the rubber composition, in particular, the amount of filler (especially silica) added. The durometer hardness (Type A) of a vulcanized molded article of the rubber composition can be determined by the method described in the examples. According to the present invention, even when the hardness is adjusted to a low level, vulcanized products and vulcanized molded articles with excellent abrasion resistance, tensile properties, and resistance to compression set can be obtained.

[0083] <Tensile properties of vulcanized molded articles> In one embodiment of the present invention, the rubber composition preferably has a tensile strength at break of 16 MPa or more, according to JIS K 6251, for a vulcanized molded article of the rubber composition. The tensile strength at break of a vulcanized molded article of the rubber composition may be, for example, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, or 40 MPa, and may be within the range of any two of the values ​​exemplified herein. According to one embodiment of the present invention, it is possible to obtain a vulcanized product and a vulcanized molded article that can be sufficiently vulcanized while containing silica and has sufficient tensile strength.

[0084] The rubber composition according to one embodiment of the present invention can have an elongation at break of 300 to 1200% according to JIS K 6251 for a vulcanized molded article of the rubber composition. The elongation at break of a vulcanized molded article of the rubber composition may be, for example, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, or 1200%, and may be within the range of any two of the values ​​exemplified here. The tensile strength and elongation at break of a vulcanized molded article of a rubber composition can be determined by the method described in the examples.

[0085] <Compression set resistance> A rubber composition according to one embodiment of the present invention can achieve a compression set of 35% or less for a vulcanized molded article of the rubber composition under test conditions of 70°C and 24 hours according to JIS K 6262:2013. The compression set may be, for example, 0, 5, 10, 15, 20, 25, 30, or 35%, and may be within the range of any two of the values ​​exemplified herein. The compression set of a vulcanized molded article of the rubber composition can be determined by the method described in the examples.

[0086] <Abrasion Resistance> The rubber composition according to one embodiment of the present invention has an abrasion volume ΔV of 50 mm² as determined by the Akron abrasion test (1000 abrasions) based on JIS K 6264-2:2019. 3 The following are preferable: The wear volume ΔV is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 mm 3 The value may be within the range of any two of the values ​​exemplified here. The wear volume ΔV of the vulcanized molded article of the rubber composition can be determined by the method described in the examples.

[0087] 4. Unvulcanized molded articles, vulcanized articles, and vulcanized molded articles The unvulcanized molded article according to this embodiment uses the rubber composition according to this embodiment and is a molded article of the rubber composition (unvulcanized state) according to this embodiment. The method for manufacturing the unvulcanized molded article according to this embodiment includes a step of molding the rubber composition (unvulcanized state) according to this embodiment. The unvulcanized molded article according to this embodiment consists of the rubber composition (unvulcanized state) according to this embodiment.

[0088] The vulcanized product according to this embodiment is a vulcanized product of the rubber composition according to this embodiment. The method for manufacturing the vulcanized product according to this embodiment comprises the step of vulcanizing the rubber composition according to this embodiment.

[0089] The vulcanized molded article according to this embodiment is a vulcanized molded article of the rubber composition according to this embodiment. The vulcanized molded article according to this embodiment uses the vulcanized product according to this embodiment and is a molded article (molded product) of the vulcanized product according to this embodiment. The vulcanized molded article according to this embodiment consists of the vulcanized product according to this embodiment.

[0090] The vulcanized molded article according to this embodiment can be obtained by molding a vulcanized product obtained by vulcanizing the rubber composition (unvulcanized state) according to this embodiment, or by vulcanizing a molded article obtained by molding the rubber composition (unvulcanized state) according to this embodiment. The vulcanized molded article according to this embodiment can be obtained by vulcanizing the rubber composition according to this embodiment after molding or during molding. The method for manufacturing the vulcanized molded article according to this embodiment comprises the steps of molding a vulcanized product according to this embodiment, or vulcanizing an unvulcanized molded article according to this embodiment.

[0091] The unvulcanized molded articles, vulcanized articles, and vulcanized molded articles according to this embodiment 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 abrasion resistance and can therefore be used as various components where these properties are required. The rubber composition, vulcanized articles, and vulcanized molded articles 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 components such as automotive rubber components (e.g., automotive sealing materials), hose materials, rubber molds, gaskets, rubber rolls, industrial cables, industrial conveyor belts, and sponges. In particular, they can be used for components where abrasion resistance is required. As an example, the vulcanized articles and vulcanized molded articles according to one embodiment of the present invention can be suitably used as rubber rolls. As an example, the vulcanized articles and vulcanized molded articles according to one embodiment of the present invention can be suitably used as embossing rubber rolls where abrasion resistance is particularly required.

[0092] (Rubber components for automobiles) Automotive rubber components include gaskets, oil seals, and packings, which are parts used in machinery and equipment to prevent leakage of liquids and gases, and to prevent the intrusion of dirt and foreign matter such as rainwater and dust. Specifically, there are gaskets used for fixed applications, and oil seals and packings used in moving and movable parts. In gaskets where the sealing part is fixed with bolts, various materials are used depending on the purpose, as opposed to soft gaskets such as O-rings and rubber sheets. Packings are used in rotating parts such as the shafts of pumps and motors and the movable parts of valves, reciprocating parts such as pistons, coupler connections, and water-stopping parts of water faucets. The rubber composition of the present invention can enhance abrasion resistance. This makes it possible to manufacture seals that can be used in harsh environments, which was difficult with conventional rubber compositions.

[0093] (Hose material) Hose materials are flexible tubes, and specifically include high and low-pressure hoses for water, oil, air, steam, and hydraulics. The rubber composition of the present invention can improve the abrasion resistance of hose materials while maintaining the processability of the unvulcanized material. This makes it possible to manufacture hose materials for use in harsh environments, which was difficult with conventional rubber compositions.

[0094] (Rubber molded object) Rubber-type products include vibration-damping rubber, vibration-damping materials, and boots. Vibration-damping rubber and vibration-damping materials are rubber that prevents the transmission and propagation of vibrations. Specifically, they include torsional dampers, engine mounts, and muffler hangers for automobiles and various other vehicles that absorb vibrations during engine operation and prevent noise. The rubber composition of the present invention can improve the wear resistance of vibration-damping rubber and vibration-damping materials. This makes it possible to manufacture vibration-damping rubber and vibration-damping materials that can be used even in harsh environments, which was difficult with conventional rubber compositions. Furthermore, boots are bellows-shaped components whose outer diameter gradually increases from one end to the other. Specifically, examples include constant velocity joint cover boots, ball joint cover boots (dust cover boots), and rack and pinion gear boots for protecting drive components such as automobile drive systems. The rubber composition of the present invention can enhance wear resistance. This makes it possible to manufacture boots that can be used in harsher environments than those made with conventional rubber compositions.

[0095] (Gaskets, etc.) Gaskets, oil seals, and packings are components in machinery and equipment that prevent leakage of liquids and gases, as well as the intrusion of dirt and foreign matter such as rainwater and dust. Specifically, there are gaskets used for fixed applications and oil seals and packings used in moving parts. For gaskets where the sealing portion is fixed with bolts, various materials are used depending on the purpose, as opposed to soft gaskets such as O-rings and rubber sheets. Packings are used in rotating parts such as the shafts of pumps and motors and the movable parts of valves, reciprocating parts such as pistons, coupler connections, and water-stopping parts of water faucets. The rubber composition of the present invention can improve the wear resistance of these components. This makes it possible to manufacture seals that can be used even in harsh environments, which was difficult with conventional rubber compositions.

[0096] (Rubber roll) Rubber rolls are manufactured by bonding and covering a metal core, such as an iron core, with rubber. Generally, they are manufactured by spirally winding a rubber sheet around a metal core. Rubber rolls are made from various rubber materials such as NBR, EPDM, and CR, depending on the required characteristics for various applications, including papermaking, various metal manufacturing, film manufacturing, printing, general industrial use, agricultural machinery such as rice hulling machines, and food processing. CR is used in a wide range of rubber roll applications because it has good mechanical strength that can withstand the friction of the objects being conveyed. Furthermore, rubber rolls that convey heavy objects have the problem of deforming under load, and improvements are needed. The rubber composition of the present invention can improve the abrasion resistance of rubber rolls. This makes it possible to manufacture embossing rubber rolls with excellent abrasion resistance, which was difficult with conventional rubber compositions.

[0097] (Industrial cables) Industrial cables are linear components used to transmit electrical and optical signals. They consist of good conductors such as copper or copper alloys, or optical fibers, covered with an insulating coating layer. 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 abrasion resistance of industrial cables. This makes it possible to manufacture industrial cables that can be used even in harsh environments, which was difficult with conventional rubber compositions.

[0098] (Industrial conveyor belt) Industrial conveyor belts are made of rubber, resin, or metal, and are selected according to a wide variety of applications. Among these, rubber conveyor belts are inexpensive and widely used, but they are prone to deterioration and damage, especially in environments with high friction and collision with conveyed materials. The rubber composition of the present invention can improve the abrasion resistance of industrial conveyor belts. This makes it possible to manufacture industrial conveyor belts that can be used in harsh environments, which was difficult with conventional rubber compositions.

[0099] (sponge) Sponge is a porous material with countless fine pores inside, and is specifically used in vibration damping components, sponge seal parts, wetsuits, shoes, and the like. The rubber composition of the present invention can improve the acid resistance and water resistance of sponge. Furthermore, because it uses chloroprene-based rubber, it can also improve the flame retardancy of sponge. This makes it possible to manufacture sponges that can be used in harsh environments, which was difficult with conventional rubber compositions, and sponges with excellent flame retardancy. In addition, the hardness of the resulting sponge can be adjusted as appropriate by adjusting the content of the foaming agent, etc.

[0100] Methods for forming the rubber composition (unvulcanized) and vulcanized product according to this embodiment include press molding, extrusion molding, and calendering. The temperature for vulcanizing the rubber composition can 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 can be set appropriately depending on the composition of the rubber composition, the shape of the unvulcanized molded product, etc.

[0101] <Second perspective> 1. Rubber composition A rubber composition according to one embodiment of the present invention is a rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, wherein when the rubber composition is press-vulcanized at 160°C for 40 minutes to obtain a vulcanized molded article, the wear volume ΔV of the vulcanized molded article at 1000 rotations in the Akron abrasion test according to JIS K 6264-2 is 50 mm 3 The following applies: According to the rubber composition relating to the second aspect, in a rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, the wear volume ΔV of the vulcanized molded body of the rubber composition is 50 mm 3 By adjusting the rubber composition as follows, a vulcanized molded article with excellent abrasion resistance, tensile properties, and resistance to compression set can be obtained. The following explanation will focus on the differences from the first perspective.

[0102] 1.1 The method for producing chloroprene-based rubber and 1.2 the method for producing chloroprene-based rubber are the same as in the first section.

[0103] 1.3 3-Methyl-thiazoldin-2-thion, Compound A and Compound B The rubber composition relating to the second aspect may contain at least one of 3-methyl-thiazoldin-2-thion, compound A, and compound B. Compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds. In a chloroprene-based rubber composition containing silica, incorporating the above compound allows for more sufficient vulcanization, resulting in a rubber composition that provides vulcanized products and molded articles with excellent abrasion resistance.

[0104] The rubber composition relating to the second aspect may contain a total content of 3-methyl-thiazoldin-2-thion, compound A, and compound B in an amount of 0.1 to 3.0 parts by mass per 100 parts by mass of chloroprene rubber. Specifically, the total content of 3-methyl-thiazoldin-2-thion, compound A, and compound B in an amount of 100 parts by mass of chloroprene rubber may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0105] The content of 3-methyl-thiazoldin-2-thion in the rubber composition relating to the second aspect can be 0 to 3.0 parts by mass per 100 parts by mass of chloroprene rubber. Specifically, for example, it can be 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may be within the range of any two of the values ​​exemplified here.

[0106] The content of compound A in the rubber composition relating to the second aspect can be 0 to 3.0 parts by mass per 100 parts by mass of chloroprene rubber. Specifically, for example, it can be 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may also be within the range of any two of the values ​​exemplified here.

[0107] The content of compound B in the rubber composition relating to the second aspect can be 0 to 3.0 parts by mass per 100 parts by mass of chloroprene rubber. Specifically, for example, it can be 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 parts by mass, and may also be within the range of any two of the values ​​exemplified here.

[0108] Specific examples of 3-methyl-thiazoldin-2-thion, compound A, and compound B are the same as in the first aspect.

[0109] The rubber composition relating to the second aspect is more preferably satisfied with at least one of the following conditions i) and ii). Condition i) The rubber composition contains 3-methyl-thiazoldin-2-thion, and contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of the chloroprene rubber. Condition ii) The rubber composition comprises compound A and compound B, wherein compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide, and compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds, and the rubber composition contains 0.1 to 3.0 parts by mass of compound A and 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of the chloroprene rubber.

[0110] Conditions i) and / or ii) are the same as in the first point of view.

[0111] 1.4 Silica, 1.5 Silane coupling agent, 1.6 Hydrate, 1.7 Acid acceptor, 1.8 Plasticizer, 1.9 Lubricant, processing aid, 1.10 Other components, 2. The method for producing the rubber composition is the same as in the first aspect.

[0112] 3. Properties of rubber compositions <Abrasion Resistance> The rubber composition relating to the second aspect is such that when a vulcanized molded article is obtained by press-vulcanizing the rubber composition at 160°C for 40 minutes, the wear volume ΔV of the vulcanized molded article at 1000 rotations (number of rotations of the polishing wheel) in the Akron abrasion test according to JIS K 6264-2 is 50 mm 3 The following applies: The wear volume ΔV is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 mm. 3 The value may be within the range of any two of the values ​​exemplified here. The wear volume ΔV of the vulcanized molded article of the rubber composition can be determined by the method described in the examples. According to the rubber composition relating to the second aspect, in a rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, the wear volume ΔV of the vulcanized molded body of the rubber composition is 50 mm 3 By adjusting the rubber composition as described below, a vulcanized molded article with excellent abrasion resistance, tensile properties, and resistance to compression set can be obtained. The wear volume ΔV of the vulcanized molded article of the rubber composition can be controlled by adjusting the type and amount of each component in the rubber composition.

[0113] <Hardness of vulcanized molded products> The rubber composition relating to the second aspect allows for a durometer hardness (Type A) of the vulcanized molded article obtained by press vulcanization of the rubber composition at 160°C for 40 minutes, with a durometer hardness of 30 to 90 as defined in JIS K 6253. The durometer hardness (Type A) of the 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 the range of any two of the values ​​exemplified here. The durometer hardness (Type A) of the vulcanized molded article of the rubber composition can be controlled by adjusting the type and amount of compounding in the rubber composition, in particular, the amount of filler (especially silica). The durometer hardness (Type A) of the vulcanized molded article of the rubber composition can be determined by the method described in the examples. According to the present invention, even when the hardness is adjusted to a low level, vulcanized products and vulcanized molded articles with excellent abrasion resistance, tensile properties, and resistance to compression set can be obtained. Furthermore, according to one embodiment of the present invention, by adjusting the type and amount of rubber composition so that the hardness falls within the above numerical range, the type and amount of each component including silica, silane coupling agent, and hydrate can be indirectly adjusted, thereby obtaining vulcanized products and vulcanized molded articles that have appropriate hardness while also having superior abrasion resistance, tensile properties, and resistance to compression set.

[0114] The tensile properties and compression set resistance of the vulcanized molded articles of the rubber composition relating to the second aspect are the same as those relating to the first aspect.

[0115] 4. The same applies to unvulcanized molded articles, vulcanized products, and vulcanized molded articles as in the first point of view. [Examples]

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

[0117] <Manufacturing of chloroprene-acrylonitrile copolymer rubber> In a 3-liter polymerization vessel equipped with a heating / cooling jacket and a stirrer, 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, Inc.), 0.40 parts by mass of sodium hydroxide, and 2.0 parts by mass of sodium salt of β-naphthalene sulfonic acid formalin condensate (manufactured by Kao Corporation) were added. 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 atmosphere. Chloroprene monomer was added from 20 seconds after the start of polymerization, and the addition flow rate was adjusted with a solenoid valve based on the change in the heat quantity of the refrigerant during the first 10 seconds of polymerization, and then readjusted every 10 seconds thereafter to continue the process. When the polymerization rate reached 50% of the total amount of chloroprene monomer and acrylonitrile monomer, 0.02 parts by mass of phenothiazine, a polymerization inhibitor, was added to stop the polymerization. Subsequently, unreacted monomers were removed from the reaction solution under reduced pressure to obtain chloroprene-acrylonitrile copolymer latex.

[0118] The polymerization rate [%] of the chloroprene-acrylonitrile copolymer latex mentioned above was calculated from the dry mass of the chloroprene-acrylonitrile copolymer latex after air drying. Specifically, it was calculated using the following formula (A). In the formula, "solid content concentration" is the concentration of solids [mass %] obtained by heating 2 g of sampled chloroprene-acrylonitrile copolymer latex at 130°C and removing volatile components such as solvent (water), volatile chemicals, and raw materials. "Total charge" is the total amount [g] of raw materials, reagents, and solvent (water) charged into the polymerization tank from the start of polymerization to a certain time. "Evaporation residue" is the mass [g] of chemicals [g] that remain as solids with the polymer without volatilizing under 130°C conditions, out of the chemicals and raw materials charged from the start of polymerization to a certain time. "Monomer charge" is the sum of the amount [g] of monomers initially charged into the polymerization tank and the amount of monomers added from the start of polymerization to a certain time. In this context, "monomer" refers to the total amount of chloroprene and acrylonitrile. Polymerization rate = {[(Total amount charged × Solid content concentration / 100) - Evaporation residue] / Amount of monomer charged} × 100 ... (A)

[0119] The pH of the chloroprene-acrylonitrile copolymer latex described above was adjusted to 7.0 using acetic acid or sodium hydroxide. A sheet was then obtained by emulsifying and destroying the chloroprene-acrylonitrile copolymer latex by freezing and solidifying it on a metal plate cooled to -20°C. After washing this sheet with water, it was dried at 130°C for 15 minutes to obtain a solid chloroprene-acrylonitrile copolymer rubber (chloroprene-acrylonitrile copolymer).

[0120] The chloroprene-acrylonitrile copolymer rubber described above was prepared as a 0.1% by mass solution with THF, and then the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the chloroprene-acrylonitrile copolymer rubber were measured using a high-speed GPC instrument (TOSOH HLC-8320GPC: manufactured by Tosoh Corporation) (in standard polystyrene equivalent). A TSK Guard column HHR-H was used as the pre-column, and three HSKgel GMHHR-H columns were used as the analytical columns. The samples were flushed at a sample pump pressure of 8.0-9.5 MPa, a flow rate of 1 mL / min, and 40°C, and detected using a differential refractometer.

[0121] The elution time and molecular weight were obtained using a calibration curve created by measuring a total of nine standard polystyrene samples with known molecular weights, as listed below. Mw = 8.42 × 10 6 , 1.09 × 10 6 , 7.06×10 5 , 4.27×10 5 , 1.90×10 5 , 9.64×10 4 , 3.79 × 10 4 , 1.74 × 10 4 , 2.63 × 10 3

[0122] The weight-average molecular weight (Mw) of chloroprene-acrylonitrile copolymer rubber is 473 × 10⁻¹⁴. 3 The molecular weight is g / mol, and the number-average molecular weight (Mn) is 138 × 10⁻¹⁵. 3 The concentration was g / mol, and the molecular weight distribution (Mw / Mn) was 3.4.

[0123] The monomer content of acrylonitrile in chloroprene-acrylonitrile copolymer rubber was calculated from the nitrogen atom content in the chloroprene-acrylonitrile copolymer rubber. Specifically, the nitrogen atom content in 100 mg of chloroprene-acrylonitrile copolymer rubber was measured using an elemental analyzer (Sumigraph 220F: manufactured by Sumika Analysis Center Co., Ltd.), and the monomer content of acrylonitrile was calculated. The monomer content of acrylonitrile was 9.9% by mass.

[0124] The elemental analysis described above was performed 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 at 80 mL / min as the carrier gas. A calibration curve was created using aspartic acid (10.52%) with a known nitrogen content as the standard substance.

[0125] <Preparation of rubber composition> As shown in Tables 1-3, the rubber compositions of the examples and comparative examples were obtained by mixing each component and kneading in an 8-inch open roll. In Comparative Example 1, the viscosity of the compound became too high, increasing heat generation during processing, and the crosslinking reaction progressed, resulting in hardening. In addition, the rubber compositions of Comparative Examples 5-12 did not undergo the vulcanization reaction even after heating and molding, and therefore did not exhibit rubber elasticity.

[0126] The components used to obtain the rubber composition are as follows: (Chloroprene-based rubber) Acrylonitrile-containing chloroprene rubber: The chloroprene-acrylonitrile copolymer rubber described above. Mercaptan-modified chloroprene rubber: "S-40V" manufactured by Denka Co., Ltd.

[0127] (Filler) Silica Nipsil AQ: Manufactured by Tosoh Silica Co., Ltd. (BET specific surface area 187 m²) 2 / g) Silica Carplex 1120: "Carplex 1120", (BET specific surface area 120m²) 2 / g, average particle size 12μm)

[0128] (Silane coupling agent) Amino group-containing silane coupling agent: KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd., N-phenyl-3-aminopropyltrimethoxysilane

[0129] [ka] Amino group-free silane coupling agent: "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacryloxypropyltrimethoxysilane

[0130] [ka]

[0131] (Compound A and 3-methyl-thiazoldin-2-thion) Thiourea compound Noxellar TMU: "Noxellar TMU" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trimethylthiourea Thiourea compound Accel 22S: "Accel 22S" manufactured by Kawaguchi Chemical Industry Co., Ltd., ethylene thiourea Di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide: MLPC International, "MIXLAND+SD 75 GA F250" 3-Methyl-thiazoldin-2-thion: Lanxess Corporation's "Renogran MTT-80",

[0132] (Compound B) Thiuram-based compound Noxellar TT: "Noxellar TT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., tetramethylthiuram disulfide Sulfenamide compound Noxellar CZ: "Noxellar CZ" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N-cyclohexyl-2-benzothiazolyl sulfenamide Thiazole compound Noxellar DM: "Noxellar DM" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., di-2-benzothiazolyl disulfide Guanidine compound Noxellar DT: "Noxellar DT" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., 1,3-di-o-tolylguanidine DBU (diazabicycloundecene) compound Renogran XLA-60: Lanxess's "Renogran XLA-60" contains 60% by mass of a synthetic mixture of active amine (DBU) and a retarder. Benzimidazole compound Nocrac MB: "Nocrac MB" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., mercapto-benzimidazole N-phenyl-N-(trichloromethylthio)benzenesulfonamide: Lanxess "BullCurrent E / C"

[0133] (hydrate) DHT-4A: “DHT-4A” manufactured by Kyowa Chemical Industry Co., Ltd., Mg 4.3 Al2(OH) 12.6 CO3·3.5H2O ZHT-4A: Manufactured by Kyowa Chemical Industry Co., Ltd. "ZHT-4A", Mg3ZnAl2(OH) 12 CO3·3H2O

[0134] Acid acceptor ZnO: "Zinc Oxide Type 2" manufactured by Sakai Chemical Industry Co., Ltd. Plasticizer RS-700: ADEKA Corporation's "ADEKA Sizer RS-700" polyether ester type. Lubricant: Stearic acid: "Stearic acid 50S" manufactured by Shin-Nippon Rika Co., Ltd. Anti-aging agent Nocrack CD: "Nocrack CD" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., 4,4'-bis(α,α-dimethylbenzyl)diphenylamine

[0135] <Hardness (Type A Durometer)> The obtained rubber composition was press-vulcanized at 160°C for 40 minutes according to JIS K6299 to produce a 2 mm thick sheet-like vulcanized molded article. The obtained sheet-like vulcanized molded article was measured for durometer hardness (Type A) as specified in JIS K 6253 using a GS-610 (manufactured by Teclock Co., Ltd.). The results are shown in Tables 1 to 4.

[0136] <Tensile properties> The obtained rubber composition was press-vulcanized at 160°C for 40 minutes according to JIS K6299 to produce a 2 mm thick sheet-like vulcanized molded body. According to JIS K 6251, the above-mentioned sheet-like vulcanized molded body was molded into a 2 mm thick dumbbell-shaped No. 3 test piece, and four test pieces were prepared. The tensile strength and elongation at break of each test piece were measured at a tensile speed of 500 mm / min using an AGS-X manufactured by Shimadzu Corporation. The results are shown in Tables 1 to 4.

[0137] <Compression set resistance> For cylindrical vulcanized molded bodies with a diameter of 29 mm and a height of 12.5 mm, obtained by press vulcanization at 160°C for 50 minutes, the compression set was measured under test conditions of 70°C for 24 hours, in accordance with JIS K 6262:2013. The results are shown in Tables 1 to 4.

[0138] <Abrasion Resistance> The obtained rubber composition was press-vulcanized at 160°C for 40 minutes to produce a vulcanized molded body with a diameter of 63.6 mm, a thickness of 12.7 mm, and a central hole of 12.7 mm. The obtained vulcanized molded body was subjected to an Akron abrasion test (1000 abrasions, abrasion volume ΔV, unit: mm) based on JIS K 6264-2:2019. 3 The following was performed. The results are shown in Tables 1 to 4.

[0139] [Table 1]

[0140] [Table 2]

[0141] [Table 3]

[0142] [Table 4]

Claims

1. A rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, The hydrate is at least one hydrate selected from hydrotalcite compounds, hydrated salts, and metal hydroxides. The rubber composition contains 5 to 80 parts by mass of silica and 0.5 to less than 20 parts by mass of hydrate per 100 parts by mass of the chloroprene rubber. The rubber composition contains 0.5 to 15 parts by mass of the silane coupling agent per 100 parts by mass of the silica. The rubber composition is a rubber composition that satisfies at least one of the following conditions i) and ii). Condition i) The rubber composition contains 3-methyl-thiazoldin-2-thion, The rubber composition contains 0.1 to 3.0 parts by mass of 3-methyl-thiazoldin-2-thion per 100 parts by mass of the chloroprene-based rubber. Condition ii) The rubber composition comprises compound A and compound B, Compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide. Compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds. The rubber composition contains 0.1 to 3.0 parts by mass of compound A and 0.01 to 3.0 parts by mass of compound B per 100 parts by mass of the chloroprene-based rubber.

2. The rubber composition according to claim 1, wherein the chloroprene rubber contains unsaturated nitrile monomer units.

3. The rubber composition according to claim 1 or claim 2, wherein the silane coupling agent is a silane coupling agent having an amino group in its structure.

4. The hydrate, in a temperature range of 100°C to 250°C, contains H ２ The rubber composition according to claim 1 or claim 2, which is a hydrate that releases oxygen.

5. The rubber composition according to claim 1 or claim 2, wherein the hydrate is at least one hydrate selected from a hydrotalcite compound represented by the following chemical formula (1), a hydrated salt, and a metal hydroxide. [M ２＋ １－ｘ M ３＋ ｘ (OH) ２ ] ｘ＋ [A ｎ－ ｘ／ｎ ・mH ２ O] ｘ－ (1) (M ２＋ : Mg ２＋ Mn ２＋ Fe ２＋ Co ２＋ Ni ２＋ ,Cd ２＋ , Zn ２＋ At least one divalent metal ion selected from M ３＋ : Al ３＋ Fe ３＋ , Cr ３＋ Co ３＋ In ３＋ At least one trivalent metal ion selected from A ｎ－ : OH － F － , Cl － , Br － NO ３ － CO ３ ２－ SO ４ ２－ Fe(CN) ６ ３－ ,CH ３ COO － At least one n-type anion selected from (X: 0 < X ​​≤ 0.33)

6. The hydrate is Mg ４．３ Al ２ (OH) １２．６ CO ３ 3.5H ２ O, Mg ３ ZnAl ２ (OH) １２ CO ３ 3H ２ O, Mg ４．５ Al ２ (OH) １３ CO ３ 3.5H ２ O, Mg ４．５ Al ２ (OH) １３ CO ３ Mg ４ Al ２ (OH) １２ CO ３ 3.5H ２ O, Mg ６ Al ２ (OH) １６ CO ３ 4H ２ O, Mg ５ Al ２ (OH) １４ CO ３ 4H ２ O, Mg ３ Al ２ (OH) １０ CO ３ 1.7H ２ The rubber composition according to claim 5, wherein the rubber composition is at least one hydrate selected from hydrotalcite compounds represented by O.

7. The BET specific surface area of ​​the aforementioned silica is 50 to 300 m². ２ The rubber composition according to claim 1 or claim 2, wherein the weight is / g.

8. The rubber composition comprises compound A and compound B, The rubber composition contains 10 to 100 parts by mass of compound B with respect to 100 parts by mass of compound A. The rubber composition according to claim 1 or claim 2.

9. A rubber composition comprising chloroprene rubber, silica, a silane coupling agent, and a hydrate, The hydrate is at least one hydrate selected from hydrotalcite compounds, hydrated salts, and metal hydroxides. When the rubber composition is press-vulcanized at 160°C for 40 minutes to obtain a vulcanized molded body, the wear volume ΔV of the vulcanized molded body at 1000 rotations in the Akron abrasion test according to JIS K 6264-2 is 50 mm ３ The following: The rubber composition comprises at least one selected from the group consisting of 3-methyl-thiazoldin-2-thion, compound A, and compound B. Compound A is at least one selected from thiourea compounds, 3-methyl-thiazoldin-2-thion, and di(5-mercapto-1,3,4-thiadiazole-2-yl) disulfide. A rubber composition in which compound B is at least one selected from thiram compounds, sulfenamide compounds, thiazole compounds, guanidine compounds, benzimidazole compounds, N-phenyl-N-(trichloromethylthio)benzenesulfonamide, and diazabicycloundecene compounds.

10. The rubber composition according to claim 9, wherein the durometer hardness (Type A) of the vulcanized molded article, as defined in JIS K 6253, is 30 to 90.

11. The rubber composition contains 5 to 80 parts by mass of silica and 0.5 to less than 20 parts by mass of the hydrate, per 100 parts by mass of the chloroprene rubber. The rubber composition according to claim 9 or claim 10, wherein the rubber composition contains 0.5 to 15 parts by mass of the silane coupling agent per 100 parts by mass of the silica.

12. A vulcanized product of the rubber composition according to claim 1 or claim 9.

13. A vulcanized molded article of the rubber composition according to claim 1 or claim 9.

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