Composition, vulcanizate, and vulcanized molded article

Abstract

Provided is a composition that is excellent in the balance among all of the Mooney viscosity and scorch time in the unvulcanized form of the composition and the acid resistance, waterproofness, mechanical characteristics and cold resistance of a vulcanized molded body obtained from the composition. The present invention provides a composition comprising a component R, which is at least one selected from among a chloroprene-based rubber having an unsaturated nitrile monomer unit content of less than 25 mass%, a hydrogenated acrylonitrile butadiene rubber, an acrylonitrile butadiene rubber, a chlorosulfonated polyethylene and natural rubber, and a plasticizer P. This composition contains 0.1-25 parts by mass of the plasticizer P per 100 parts by mass of the component R. The plasticizer P, which has a weight average molecular weight of 150-800, is an alicyclic epoxy resin P1 and / or a plasticizer P2 having no ester group.

Description

Technical Field

[0001] The present invention relates to a composition, a vulcanizate, and a vulcanized molded article containing rubber or an elastomer. For example, chloroprene rubber has excellent mechanical strength, weather resistance, chemical resistance, heat resistance, cold resistance, and oil resistance, and is therefore widely used as a material for general industrial transmission belts, conveyor belts, automotive air springs, vibration isolation rubbers, hoses, wipers, dipped products, seal parts, adhesives, boots, rubber draw cloths, rubber rolls, etc.

Background Art

[0002] For example, Patent Document 1 discloses an invention related to a sulfur-modified chloroprene rubber composition comprising sulfur-modified chloroprene rubber, a vulcanization accelerator, zinc oxide, and magnesium oxide, wherein the blending amount of the vulcanization accelerator is 0.1 to 5 parts by weight, and the blending amounts of zinc oxide and magnesium oxide are specified by a previously obtained relational expression between the respective blending amounts and the Mooney scorch time t. Further, Patent Document 2 discloses an invention related to a copolymer of chloroprene monomer and an unsaturated nitrile compound having a Mooney viscosity ML(1+4)100°C of 20 to 80 and having a functional group with a specific structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there was room for improvement in the acid resistance and water resistance of the vulcanized molded product of the conventional composition containing rubber or elastomer. Also, it was difficult to obtain a composition excellent in the balance of the Mooney viscosity, scorch time of the unvulcanized product of the composition, and the acid resistance, water resistance, mechanical properties, and cold resistance of the vulcanized product of the composition.

[0005] The present invention has been made in view of such circumstances, and provides a composition excellent in the balance of the Mooney viscosity, scorch time of the unvulcanized product of the composition, and the acid resistance, water resistance, mechanical properties, and cold resistance of the vulcanized molded product of the composition, which has been difficult with the conventional composition containing rubber or elastomer.

Means for Solving the Problems

[0006] According to the present invention, there is provided a composition containing at least one component R selected from chloroprene rubber, hydrogenated acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, chlorosulfonated polyethylene, and natural rubber, in which the content of the unsaturated nitrile monomer unit is less than 25% by mass, and a plasticizer P. The composition contains 0.1 to 25 parts by mass of the plasticizer P with respect to 100 parts by mass of the component R. The plasticizer P has a weight average molecular weight of 150 to 800, and the plasticizer P is at least one of an alicyclic epoxy resin P1 and a plasticizer P2 having no ester group.

[0007] As a result of intensive studies, the present inventor has found that by incorporating a plasticizer P having a specific structure into a composition containing rubber or elastomer and defining the content of the plasticizer P and the molecular weight of the plasticizer P, a composition excellent in the balance of the Mooney viscosity, scorch time of the unvulcanized product of the composition, and the acid resistance, water resistance, mechanical properties, and cold resistance of the vulcanized molded product of the composition can be obtained, leading to the completion of the present invention.

[0008] According to another aspect of the present invention, there is provided a vulcanized product of the composition described above. According to another aspect of the present invention, there is provided a vulcanized molded article using the vulcanizate described above.

[0009] Hereinafter, various embodiments of the present invention will be exemplified. The embodiments shown below can be combined with each other. It is possible. [1] A composition comprising at least one component R selected from chloroprene rubber, hydrogenated acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, chlorosulfonated polyethylene, and natural rubber, in which the content of unsaturated nitrile monomer units is less than 25% by mass, and a plasticizer P. The composition contains 0.1 to 25 parts by mass of the plasticizer P with respect to 100 parts by mass of the component R. The plasticizer P has a weight average molecular weight of 150 to 800, and the plasticizer P is at least one of an alicyclic epoxy resin P1 and a plasticizer P2 having no ester group. [2] The composition according to [1], wherein the unsaturated nitrile monomer unit is a monomer unit derived from acrylonitrile. [3] The composition according to [1] or [2], which contains 20 to 80 parts by mass of a filler with respect to 100 parts by mass of the component R. [4] The composition according to any one of [1] to [3], which contains 0.1 to 15 parts by mass of hydrotalcite with respect to 100 parts by mass of the component R. [5] The composition according to any one of [1] to [4], wherein the plasticizer P2 having no ester group contains at least one plasticizer selected from bisphenol A type liquid epoxy resin and bisphenol F type liquid epoxy resin. [6] The composition according to any one of [1] to [5], which contains 1 part by mass or more of at least one compound selected from carboxylic acid hydrazide and carboxylic acid dihydrazide with respect to 100 parts by mass of the plasticizer P2 having no ester group. [7] A vulcanizate of the composition according to any one of [1] to [6]. [8] A vulcanized molded article using the vulcanizate according to [7].

Advantages of the Invention

[0010] The composition according to the present invention is excellent in the Mooney viscosity and scorch time of the unvulcanized product of the composition, and has excellent processability. Further, according to the composition of the present invention, a vulcanized product excellent in the balance of all of acid resistance, water resistance, mechanical properties, and cold resistance can be obtained. The vulcanized product made of the conventional composition had room for improvement in acid resistance and water resistance. According to the composition of the present invention, while maintaining the processability in the unvulcanized product, the mechanical properties and cold resistance of the vulcanized molded body, a vulcanized product having excellent acid resistance and water resistance can be obtained, and thus it can be used as various members that require these properties. Specifically, the vulcanized molded body according to an embodiment of the present invention can be suitably used, for example, as materials such as transmission belts and conveyor belts for general industrial use, air springs for automobiles, vibration-proof rubbers, hoses, wipers, dipped products, seal parts, adhesives, boots, rubber draw sheets, and rubber rolls. In particular, it can be used as a member used in an environment where acid resistance and / or water resistance is required. As an example, the vulcanized molded body according to an embodiment of the present invention can be suitably used, particularly for rolls for steel that require acid resistance. Further, the vulcanized molded body according to an embodiment of the present invention can be suitably used as a roll for papermaking that particularly requires water resistance.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be illustrated and the present invention will be described in detail. The present invention is not limited by these descriptions. Each feature of the embodiments of the present invention shown below can be combined with each other. Further, the invention can be established independently for each feature.

[0012] 1. Composition The composition according to the present invention contains at least one component R selected from chloroprene-based rubbers, hydrogenated acrylonitrile-butadiene rubbers (H-NBR), acrylonitrile-butadiene rubbers (NBR), chlorosulfonated polyethylene (CSM), natural rubber (NR), etc., with a content rate of unsaturated nitrile monomer units of less than 25% by mass, and a plasticizer P. Further, the composition according to the present invention contains 0.1 to 25 parts by mass of a plasticizer P having a specific structure with respect to 100 parts by mass of the component R, and the plasticizer P has a weight average molecular weight of 150 to 800. The composition according to the present invention contains at least one component R selected from chloroprene-based rubbers, hydrogenated acrylonitrile-butadiene rubbers (H-NBR), acrylonitrile-butadiene rubbers (NBR), chlorosulfonated polyethylene (CSM), natural rubber (NR), etc., with a content rate of unsaturated nitrile monomer units of less than 25% by mass, and a plasticizer P. By defining the content of the plasticizer P having a specific structure and the molecular weight of the plasticizer P, the composition has an excellent balance in all of the Mooney viscosity, scorch time of the unvulcanized product of the composition, and the acid resistance, water resistance, mechanical properties, and cold resistance of the vulcanized molded product of the composition.

[0013] 1.1 Component R The composition according to the present invention contains at least one component R selected from chloroprene-based rubbers, hydrogenated acrylonitrile-butadiene rubbers (H-NBR), acrylonitrile-butadiene rubbers (NBR), chlorosulfonated polyethylene (CSM), natural rubber (NR), etc., with a content rate of unsaturated nitrile monomer units of less than 25% by mass. 1.1.1 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 homopolymer of chloroprene and a copolymer of chloroprene (a copolymer of chloroprene and a monomer copolymerizable with chloroprene). The polymer structure of the chloroprene-based polymer is not particularly limited.

[0014] In addition, 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 the present embodiment.

[0015] The chloroprene rubber according to one embodiment of the present invention includes a chloroprene rubber in which the content rate of the unsaturated nitrile monomer unit is less than 25% by mass. The chloroprene rubber according to one embodiment of the present invention has a content rate of the unsaturated nitrile monomer unit of less than 25% by mass when the rubber is 100% by mass, and it is preferable that the content rate of the unsaturated nitrile monomer unit is 1% by mass or more and less than 25% by mass. The content rate of the unsaturated nitrile monomer unit in the chloroprene 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 may be within the range between any two of the numerical values exemplified herein. By setting the content rate of the unsaturated nitrile monomer unit to less than 25% by mass, the resulting composition has sufficient cold resistance. In particular, by setting the content rate of the unsaturated nitrile monomer unit to 1% by mass or more, the resulting composition has sufficient oil resistance, and a vulcanized molded article excellent in the balance of tensile strength and cold resistance can be obtained.

[0016] Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, etc. The unsaturated nitrile can be used alone or in combination of two or more. From the viewpoint that excellent moldability is easily obtained and from the viewpoint that excellent breaking strength, breaking elongation, hardness, tear strength, and oil resistance are easily obtained in the vulcanized molded article, it is preferable to contain acrylonitrile.

[0017] The content of the unsaturated nitrile monomer unit contained in the chloroprene rubber can be calculated from the content of nitrogen atoms in the chloroprene rubber. Specifically, the content of nitrogen atoms in 100 mg of chloroprene rubber can be measured using an elemental analyzer (Sumigraph 220F: manufactured by Showa Denko K.K. Analytical Center), and the content of the structural unit derived from the unsaturated nitrile monomer can be calculated. The elemental analysis can be performed under the following conditions. For example, the electric furnace temperature is set to 900 °C for the reaction furnace, 600 °C for the reduction furnace, 70 °C for the column temperature, and 100 °C for the detector temperature. Oxygen is flowed at 0.2 mL / min as the combustion gas, and helium is flowed at 80 mL / min as the carrier gas. The calibration curve can be prepared using aspartic acid (10.52%) with a known nitrogen content as a standard substance.

[0018] The chloroprene rubber according to one embodiment of the present invention preferably contains 60 to 100% by mass of chloroprene monomer units when the component R is 100% by mass. The content rate of the chloroprene monomer units in the component R is, for example, 60, 65, 70, 75, 80, 85, 90, 95, 99, 100% by mass, and may be within the range between any two of the numerical values exemplified herein. By setting the content rate of the chloroprene monomer units within the above numerical range, a composition capable of obtaining a molded article excellent in the balance of hardness, tensile strength, and cold resistance can be obtained.

[0019] The chloroprene rubber according to one embodiment of the present invention may also have monomer units other than chloroprene monomer and unsaturated nitrile monomer. The monomer units other than chloroprene monomer and unsaturated nitrile monomer are not particularly limited as long as they are copolymerizable with chloroprene monomer or chloroprene monomer and unsaturated nitrile monomer, and examples thereof include esters of (meth)acrylic acid (methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), hydroxyalkyl (meth)acrylate (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.

[0020] The chloroprene rubber according to one embodiment of the present invention may contain 0 to 20% by mass of monomer units other than chloroprene monomer and unsaturated nitrile monomer when the chloroprene rubber is 100% by mass. The content of monomer units other than chloroprene monomer and unsaturated nitrile monomer in the chloroprene rubber is, for example, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20% by mass, and may be within the range between any two of the values exemplified herein. By adjusting the copolymerization amount of monomers other than chloroprene monomer and unsaturated nitrile monomer within this range, the effects of copolymerizing these monomers can be exhibited without impairing the properties of the resulting composition. Further, the chloroprene rubber according to one embodiment of the present invention may consist only of chloroprene monomer units and unsaturated nitrile monomer units, or may consist only of chloroprene monomer units.

[0021] The composition according to the present invention can use the chloroprene rubber alone or in combination of two or more. When the composition according to an embodiment of the present invention contains two or more chloroprene rubbers, it is preferable that the total content ratio of the unsaturated nitrile monomer units contained in the two or more chloroprene rubbers contained in the composition is less than 25% by mass.

[0022] The chloroprene polymer (homopolymer of chloroprene, copolymer of chloroprene, etc.) 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.

[0023] The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (polydispersity of molecular weight, Mw / Mn) of the chloroprene rubber may be in the following ranges from the viewpoint that excellent hardness, tensile strength, and cold resistance are easily obtained in a well-balanced manner.

[0024] The weight average molecular weight of the 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 g / mol or more. The weight average molecular weight of the 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 g / mol or less. From these viewpoints, the weight average molecular weight of the chloroprene rubber is 10×10 3 ~5000×10 3 g / mol, 100×10 3 ~2000×10 3g / mol, or 300×10 3 ~1000×10 3 g / mol.

[0025] The number average molecular weight of the chloroprene rubber is 1×10 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 g / mol or more. The number average molecular weight of the 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 g / mol or less. From these viewpoints, the number average molecular weight of the chloroprene rubber is 1×10 3 ~1000×10 3 g / mol, 10×10 3 ~500×10 3 g / mol, or 50×10 3 ~300×10 3 g / mol.

[0026] The molecular weight distribution of the chloroprene rubber may be 1.0 or more, 1.5 or more, 2.0 or more, 2.5 or more, 3.0 or more, 3.2 or more, or 3.4 or more. The molecular weight distribution of the chloroprene rubber may be 10 or less, 8.0 or less, 5.0 or less, 4.0 or less, 3.8 or less, 3.5 or less, or 3.4 or less. From these viewpoints, the molecular weight distribution of the chloroprene rubber may be 1.0~10, 2.0~5.0, or 2.5~4.0.

[0027] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the chloroprene rubber can be measured by gel permeation chromatography (GPC) and obtained by converting to polystyrene equivalent. Specifically, they can be measured by the method described in the examples.

[0028] 1.1.2 Production method of chloroprene rubber The production method of the chloroprene rubber according to the present invention is not particularly limited, but can be obtained by a production method including an emulsion polymerization step of emulsion-polymerizing a raw monomer containing a chloroprene monomer. In the emulsion polymerization step according to an embodiment of the present invention, a monomer containing a chloroprene monomer or a monomer containing a chloroprene monomer and an unsaturated nitrile monomer is emulsion-polymerized using an emulsifier, a dispersant, a catalyst, a chain transfer agent, etc. as appropriate, and a polymerization terminator is added when the target final conversion rate is reached to obtain a latex containing a chloroprene-based polymer containing a chloroprene monomer unit. Next, unreacted monomers can be removed from the polymerization solution obtained by the emulsion polymerization step. The method is not particularly limited, and for example, the steam stripping method can be mentioned. Thereafter, the pH is adjusted, and through steps such as conventional freezing and solidification, washing with water, and hot air drying, a chloroprene rubber containing a chloroprene-based polymer can be obtained.

[0029] There is no particular limitation on the polymerization initiator used in the case of emulsion polymerization, and known polymerization initiators generally used for the 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.

[0030] As the emulsifier used in the case of emulsion polymerization, there is no particular limitation, and known emulsifiers generally used in the 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 (for example, potassium rosin), alkali metal salts of formalin condensates of β-naphthalene sulfonic acid (for example, sodium salt), and the like.

[0031] As the molecular weight regulator used in the case of emulsion polymerization, there is no particular limitation, and known molecular weight regulators generally used in the emulsion polymerization of chloroprene can be used. For example, there are mercaptan compounds, xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds. As the molecular weight regulator of the chloroprene rubber according to one embodiment of the present invention, xanthogen compounds, dithiocarbonate compounds, trithiocarbonate compounds, and carbamate compounds can be preferably used.

[0032] 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. In order to adjust the final conversion rate, a polymerization terminator may be added to stop the polymerization reaction when the desired conversion rate is reached.

[0033] As the polymerization terminator, there is no particular limitation, and known polymerization terminators generally used in the emulsion polymerization of chloroprene can be used. Examples of the polymerization terminator include phenothiazine (thiodiphenylamine), 4-t-butylcatechol, 2,2-methylenebis-4-methyl-6-t-butylphenol, and the like.

[0034] The chloroprene rubber according to one embodiment of the present invention can be obtained, for example, by removing unreacted monomers by the steam stripping method, then adjusting the pH of the above latex, and passing through steps such as conventional freezing and coagulation, washing with water, and hot air drying.

[0035] Chloroprene rubber is classified into mercaptan-modified type, xanthate-modified type, sulfur-modified type, dithiocarbonate type, trithiocarbonate type, and carbamate type according to the type of molecular weight regulator.

[0036] 1.1.3 Other component R In addition to chloroprene rubber, the composition according to the present invention may use at least one component R selected from hydrogenated acrylonitrile-butadiene rubber (H-NBR), acrylonitrile-butadiene rubber (NBR), chlorosulfonated polyethylene (CSM), natural rubber (NR).

[0037] Hydrogenated acrylonitrile-butadiene rubber (H-NBR) and acrylonitrile-butadiene rubber (NBR) can be of medium to high nitrile type. Hydrogenated acrylonitrile-butadiene rubber (H-NBR) and acrylonitrile-butadiene rubber (NBR) have a bound acrylonitrile amount of, for example, 30, 35, 40, 45, 50%, and may be within the range between any two of the exemplified values.

[0038] 1.2 Plasticizer P The composition according to the present invention contains a plasticizer P, and the plasticizer is at least one of an alicyclic epoxy resin P1 and a plasticizer P2 having no ester group. The plasticizer P2 has a weight average molecular weight of 150 to 800 and is not particularly limited as long as it functions as a plasticizer, that is, a compound having a function of improving the fluidity of the unvulcanized product. The plasticizer can also improve the flexibility of the vulcanized product. The plasticizer P may also have a function as a curing type plasticizer that improves mechanical properties such as tensile strength in the vulcanized product by curing during vulcanization. The plasticizer P2 having no ester group is a compound having no ester group in its structure. Note that esters include carbonates, phosphates, sulfates, etc.

[0039] The plasticizer P has a weight average molecular weight of 150 to 800, for example, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, and may be within the range between any two of the exemplified values. By setting the weight average molecular weight to be equal to or less than the above upper limit, an increase in the Mooney viscosity and scorch time of the unvulcanized product can be prevented, and the processability can be maintained. Also, from the viewpoint of having an appropriate viscosity and the function as a plasticizer, it is preferable to set the weight average molecular weight to be equal to or more than the above lower limit.

[0040] The plasticizer P is preferably liquid at 25°C, and preferably has a viscosity at 25°C of 500 cP or more. The viscosity at 25°C is, for example, 500, 1000, 1500, 2000, 2500, 3000, 4000, 5000, 7000, 10000, 15000, 20000 cP, and may be within the range between any two of the exemplified values.

[0041] Specific examples of the plasticizer P2 having no ester group include epoxy compounds, terpene compounds, and the like. The epoxy compound is not particularly limited as long as it has an epoxy group and no ester group and has a molecular weight of 150 to 800. Examples thereof include epoxy resins having a bisphenol structure and diene-based polymers having an epoxy group (excluding chloroprene-based polymers, hydrogenated NBR, and compounds corresponding to NBR).

[0042] The epoxy resin having a bisphenol structure can be obtained by a condensation reaction of bisphenol and epichlorohydrin. As the epoxy resin having a bisphenol structure, bisphenol A-type epoxy resins containing a structure derived from bisphenol A and bisphenol F-type epoxy resins containing a structure derived from bisphenol F are preferable, and bisphenol A-type liquid epoxy resins and bisphenol F-type liquid epoxy resins are more preferable. As an example, a bisphenol A-type epoxy resin having the following structure can be mentioned.

[0043] [Chemical formula] (n in the formula is any integer that satisfies the following molecular weight definition.)

[0044] Examples of the diene polymer having an epoxy group include aliphatic conjugated diene polymers such as polybutadiene and polyisoprene having an epoxy group; aromatic vinyl - aliphatic conjugated diene copolymers such as styrene - butadiene polymer (SBR); and hydrogenated SBR. The diene polymer having an epoxy group may contain, for example, a compound represented by the following formula.

[0045] [Chemical formula] (m and n in the formula are any integers that satisfy the following molecular weight definition.)

[0046] Examples of the terpene - based compound include terpene resin, aromatic - modified terpene resin, terpene phenol resin, and hydrogenated terpene phenol resin.

[0047] Specific examples of the alicyclic epoxy resin P1 include glycidyl ester - type alicyclic epoxy - based compounds, epoxidized fatty acid alkyl esters, and the like.

[0048] Examples of the alicyclic epoxy resin P1 include compounds represented by the following formula (1), formula (2), and formula (3).

[0049] [Chemical formula]

[0050] In formula (3), X can be any organic group. For example, it can be a hydrocarbon group optionally having a substituent. As an example, it can be an alkyl group or an alkenyl group optionally having a substituent. Further, the hydrocarbon group can include a carbonyl group, an ether group (ether bond), an epoxy group, and a group formed by linking a plurality of these groups.

[0051]

Chemical formula

[0052] In formula (4), Y represents any single bond or linking group (a divalent group having one or more atoms). Examples of the linking group include a divalent hydrocarbon group (e.g., an alkylene group), a carbonyl group, an ether group (ether bond), an epoxy group, and a group formed by linking a plurality of these groups.

[0053]

Chemical formula

[0054] In formula (5), Z 1 and Z 2 can each independently be any organic group. For example, it can be a hydrocarbon group optionally having a substituent. As an example, it can be an alkyl group or an alkenyl group optionally having a substituent. Further, the hydrocarbon group can include a carbonyl group, an ether group (ether bond), an epoxy group, and a group formed by linking a plurality of these groups.

[0055] Examples of the alicyclic epoxy resin P1 include 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 1-vinyl-3,4-epoxycyclohexane, di-2-ethylhexyl 4,5-epoxycyclohexane-1,2-dicarboxylate, di(9,10-epoxystearyl) 4,5-epoxycyclohexane-1,2-dicarboxylate, and the like.

[0056] The plasticizer P can be used alone or in combination of two or more of the above-described compounds. The plasticizer P preferably contains at least one of an alicyclic epoxy resin, an epoxy compound having no ester group, and a terpene compound, and more preferably contains an epoxy compound (an alicyclic epoxy resin and / or an epoxy compound having no ester group). The plasticizer P2 having no ester group preferably contains at least one selected from bisphenol A type liquid epoxy resin and bisphenol F type liquid epoxy resin.

[0057] The composition according to one embodiment of the present invention can also contain a plasticizer having an ester group other than the alicyclic epoxy resin (i.e., a plasticizer other than the plasticizer P) as long as the effects of the present invention are not inhibited. Further, the composition according to one embodiment of the present invention can contain a plasticizer having no ester group and having a weight average molecular weight of less than 150 or more than 800, or an alicyclic epoxy resin having a weight average molecular weight of less than 150 or more than 800 as long as the effects of the present invention are not inhibited. When the total content of the plasticizers contained in the composition is 100% by mass, the total content of the plasticizers other than the plasticizer P is, for example, 0, 5, 10, 15, 20, 25, 30% by mass, and may be within the range between any two of the values exemplified herein. The composition according to one embodiment of the present invention can also not contain a plasticizer having an ester group other than the alicyclic epoxy resin. Further, the composition according to one embodiment of the present invention can not contain a plasticizer other than the plasticizer P.

[0058] Examples of the plasticizer having an ester group include phthalate plasticizers, DUP (diundecyl phthalate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DOTP (dioctyl terephthalate), DOS (dioctyl sebacate), DBS (dibutyl sebacate), DOA (dioctyl adipate), DINCH (diisononyl 1,2-cyclohexanedicarboxylate), TOP (trioctyl phosphate), TBP (tributyl phosphate) and other ester plasticizers, ether ester compounds, compounds having a phosphate ester group such as triphenyl phosphate and tricresyl phosphate, and thioether plasticizers having an ester group. In the present invention, the plasticizer may not contain oils such as vegetable oils and petroleum additives.

[0059] The composition according to the present invention contains 0.1 to 25 parts by mass of the plasticizer P with respect to 100 parts by mass of the component R. The content rate of the plasticizer P with respect to 100 parts by mass of the component R is, for example, 0.1, 0.5, 1, 5, 10, 15, 20, 25 parts by mass, and may be within the range between any two of the values exemplified here. By setting the content rate within the above numerical range, a composition can be obtained that can improve the Mooney viscosity and scorch time of the unvulcanized product, and the water resistance, acid resistance, tensile strength, and cold resistance of the vulcanized product in a well-balanced manner. When the composition according to an embodiment of the present invention contains a plasticizer other than the plasticizer P, it is preferable that the total content rate of the plasticizer P and the plasticizer other than the plasticizer P with respect to 100 parts by mass of the component R is not more than the above upper limit.

[0060] 1.3 Curing agent The composition according to an embodiment of the present invention may contain a curing agent, and the curing agent may also contain any one selected from the group consisting of carboxylic acid hydrazide and carboxylic acid dihydrazide. Specifically, examples include salicylic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, tetrahydrophthalic acid dihydrazide, phthalic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, and the like. The curing agent according to an embodiment of the present invention preferably contains carboxylic acid dihydrazide. The curing agent according to an embodiment of the present invention more preferably contains any one selected from the group consisting of isophthalic acid dihydrazide, sebacic acid dihydrazide, adipic acid dihydrazide, and dodecanedioic acid dihydrazide. These can be used alone or in combination of two or more.

[0061] The composition according to an embodiment of the present invention preferably contains at least 1 part by mass of at least one compound selected from carboxylic acid hydrazide and carboxylic acid dihydrazide with respect to 100 parts by mass of a plasticizer having no ester group and a molecular weight of 150 to 800. The composition according to an embodiment of the present invention can contain, for example, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40 parts by mass in total of carboxylic acid hydrazide and carboxylic acid dihydrazide with respect to 100 parts by mass of a plasticizer having no ester group and a molecular weight of 150 to 800, and it may also be within the range between any two of the exemplified numerical values. By setting it within the above numerical range, it is possible to improve the mechanical properties of the vulcanizate while suppressing an increase in the Mooney viscosity of the unvulcanized product and shortening the scorch time. The composition according to an embodiment of the present invention may contain carboxylic acid hydrazide and carboxylic acid dihydrazide in total within the above numerical range with respect to 100 parts by mass of the epoxy compound contained in the composition.

[0062] 1.4 Vulcanizing Agent The composition according to the present invention may contain a vulcanizing agent. The type of vulcanizing agent is not particularly limited as long as the effects of the present invention are not impaired. The vulcanizing agent is preferably a vulcanizing agent that can be used for vulcanizing chloroprene rubber. The vulcanizing agent can be freely selected and used singly or in combination of two or more. Examples of the vulcanizing agent include sulfur, metal oxides, and organic peroxides.

[0063] Examples of the metal oxide include zinc oxide, magnesium oxide, lead oxide, red lead, iron(III) oxide, titanium dioxide, calcium oxide, etc. The metal oxide preferably contains zinc oxide, and more preferably is zinc oxide.

[0064] Examples of the organic peroxide include dicumyl peroxide, benzoyl peroxide, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, diisobutyryl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, disuccinic peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, t-butyl peroxy-2-ethylhexanoate, di(3-methylbenzoyl) peroxide, benzoyl(3-methylbenzoyl) peroxide, dibenzoyl peroxide, 1,1-di(t-butylperoxy)-2-methylcyclohexane, 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxymaleic acid, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-di-methyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, 2,2-Di-(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl 4,4-di-(t-butylperoxy)valerate, 1,4-bis[(t-butylperoxy)isopropyl]benzene, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide and the like. Among these, at least one selected from dicumyl peroxide, 1,4-bis[(t-butylperoxy)isopropyl]benzene, t-butyl α-cumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 is preferable, and particularly preferably 1,4-bis[(t-butylperoxy)isopropyl]benzene.,

[0065] From the viewpoint of ensuring processing safety and obtaining good vulcanizates, when the component R contained in the composition is 100 parts by mass, the composition preferably contains 3 to 15 parts by mass of a vulcanizing agent. The content of the vulcanizing agent is, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 parts by mass when the component R contained in the composition is 100 parts by mass, and may be within the range between any two of the values exemplified herein.

[0066] The composition according to one embodiment of the present invention can contain a metal oxide and an organic peroxide. When using an organic peroxide, the addition amount of the organic peroxide can be 0.3 to 1.8 parts by mass with respect to 100 parts by mass of the chloroprene rubber. The addition amount of the organic peroxide can be, for example, 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 parts by mass, and it may be within the range between any two of the numerical values exemplified here.

[0067] 1.5 Hydrotalcite The composition according to one embodiment of the present invention can contain hydrotalcite. As the hydrotalcite, those represented by the following formula can be used. [M 2+ 1-x M 3+ x (OH)2] x+ [A n-x / n ·mH2O] x-

[0068] In the above formula, M 2+ : Mg 2+ , Zn 2+ at least one divalent metal ion selected from etc. M 3+ : Al 3+ , Fe 3+ at least one trivalent metal ion selected from etc. A n- : Co3 2- , Cl ― , NO3 2- at least one n-type anion selected from etc. X: 0 < X ≦ 0.33 can be set.

[0069] As the hydrotalcite, 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 is CO3·3H2O.

[0070] When using hydrotalcite, the addition amount of hydrotalcite can be 0.1 to 15 parts by mass with respect to 100 parts by mass of the chloroprene rubber. The addition amount of hydrotalcite is, for example, 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 parts by mass, and may be within the range between any two of the values exemplified here. Hydrotalcite can be used alone or in combination of two or more.

[0071] 1.6 Oils The composition according to the present invention can contain oils. The oils can include vegetable oils such as rapeseed oil, linseed oil, castor oil, and coconut oil, aroma oils, naphthenic oils, lubricating oils, process oils, paraffin, liquid paraffin, petrolatum, and petroleum asphalts. These can be used alone or in combination of two or more.

[0072] The composition according to one embodiment of the present invention can contain 0 to 50 parts by mass of oils when the component R contained in the composition is 100 parts by mass. For example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 parts by mass, and may be within the range between any two of the values exemplified here.

[0073] 1.7 Filler (Reinforcing Material) The composition according to the present invention can contain a filler. Examples of the filler and reinforcing material include furnace carbon black such as SAF, ISAF, HAF, EPC, XCF, FEF, GPF, HMF, SRF, modified carbon black such as hydrophilic carbon black, channel black, soot black, thermal carbon such as FT and MT, acetylene black, ketjen black, silica, clay, talc, and calcium carbonate. These can be used alone or in combination of two or more.

[0074] When the component R contained in the composition is 100 parts by mass, the composition according to an embodiment of the present invention can contain 20 to 80 parts by mass, preferably 35 to 65 parts by mass, of a filler, reinforcing material, or silica. The content of the filler, reinforcing material, or silica can be, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 parts by mass, and can also be within the range between any two of the values exemplified herein. By containing the filler within the above numerical range, the composition according to an embodiment of the present invention can further improve the hardness of the vulcanizate and vulcanized molded article.

[0075] 1.8 Silane coupling agent The composition according to an embodiment of the present invention can contain a silane coupling agent. There is no particular limitation on the silane coupling agent, and those used in commercially available compositions can be used. For example, vinyl-based coupling agents, epoxy-based coupling agents, styryl-based coupling agents, methacrylic-based coupling agents, acrylic-based coupling agents, amino-based coupling agents, polysulfide-based coupling agents, and mercapto-based coupling agents are available. In particular, vinyl-based coupling agents, methacrylic-based coupling agents, and acrylic-based coupling agents that start to react under high-temperature conditions during crosslinking are preferable from the viewpoints of scorch resistance and reinforcing effect.

[0076] As silane coupling agents, specifically, bis-(3-triethoxysilylpropyl)tetrasulfide, bis-(3-trimethoxysilylpropyl)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-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-trimethoxysilylpropyl methacryloyl monosulfide, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, isobutyltrimethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, hexyltrimethoxysilane, octadecylmethyldimethoxysilane, octadecyltrimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, triphenylchlorosilane, heptadecafluorodecylmethyldichlorosilane, heptadecafluorodecyltrichlorosilane, triethylchlorosilane and the like can be mentioned.,

[0077] In the composition according to one embodiment of the present invention, when the component R contained in the composition is 100 parts by mass, the silane coupling agent can be contained in an amount of 0.5 to 10 parts by mass, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by mass, and may be within the range between any two of the numerical values exemplified here. These can be used alone or in combination of two or more. By including the above silane coupling agent and setting the content rate of the silane coupling agent within the above numerical range, the dispersibility of the silica filler in rubber or elastomer and the reinforcing effect among rubber or the like, epoxy-based compound and silica filler can be improved, and the occurrence of scorch can be suppressed.,

[0078] 1.9 Lubricants and processing aids The composition according to the present invention may further contain a lubricant and a processing aid. The lubricant and the processing aid are mainly added to improve the processability, such as making the composition easily peel from rolls, molding dies, screws of extruders, etc. Examples of the lubricant and the processing aid include fatty acids such as stearic acid, paraffin-based processing aids such as polyethylene, fatty acid amides, petrolatum, factice, etc. These can be used alone or in combination of two or more. When the component R contained in the composition is 100 parts by mass, the composition according to the present invention can contain 1 to 15 parts by mass of the lubricant and the processing aid, and can also be 1 to 10 parts by mass. The content of the lubricant and the processing aid is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 parts by mass, and may be within the range between any two of the values exemplified herein.

[0079] 1.10 Vulcanization accelerator The composition according to the present invention may contain a vulcanization accelerator. When the component R contained in the composition is 100 parts by mass, the composition can contain 0.3 to 5.0 parts by mass of the vulcanization accelerator. The content of the vulcanization accelerator is, for example, 0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 parts by mass, and may be within the range between any two of the values exemplified herein. Note that the composition according to the present invention may not contain a vulcanization accelerator.

[0080] The type of the vulcanization accelerator is not particularly limited as long as the effects of the present invention are not impaired. The vulcanization accelerator is preferably a vulcanization accelerator that can be used for vulcanizing chloroprene rubber. One or more kinds of vulcanization accelerators can be freely selected and used. Examples of the vulcanization accelerator include thiuram-based, dithiocarbamate-based, thiourea-based, guanidine-based, xanthate-based, thiazole-based, etc.

[0081] Examples of thiuram vulcanization accelerators include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide, and the like. Examples of dithiocarbamate vulcanization accelerators include sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, tellurium diethyldithiocarbamate, and the like. Examples of thiourea vulcanization accelerators include thiourea compounds such as ethylene thiourea, diethylthiourea (N,N'-diethylthiourea), trimethylthiourea, diphenylthiourea (N,N'-diphenylthiourea), 1,3-trimethylene-2-thiourea, and the like. Examples of guanidine vulcanization accelerators include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, di-o-tolylguanidine salt of dicatecholborate, and the like. Examples of xanthate vulcanization accelerators include zinc butylxanthate, zinc isopropylxanthate, and the like. Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole, di-2-benzothiazolyldisulfide, zinc salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(4'-morpholinodithio)benzothiazole, N-cyclohexylbenzothiazole-2-sulfenamide, and the like. These can be used alone or in combination of two or more.

[0082] 1.11 Others In addition to the above-described components, the composition according to the present invention may further contain components such as an anti-aging agent, an antioxidant, a flame retardant, and a vulcanization retarder, as long as the effects of the present invention are not impaired. Examples of the anti-aging agent and the antioxidant include an ozone anti-aging agent, a phenolic anti-aging agent, an amine-based anti-aging agent, an acrylate-based anti-aging agent, an imidazole-based anti-aging agent, a metal carbamate, a wax, a phosphorus-based anti-aging agent, and a sulfur-based anti-aging agent. Examples of the imidazole-based anti-aging agent include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and a zinc salt of 2-mercaptobenzimidazole. When the component R contained in the composition is 100 parts by mass, the composition according to the present invention may contain 0.1 to 10 parts by mass of an anti-aging agent and an antioxidant.

[0083] 2. Method for producing the composition The composition according to one embodiment of the present invention can be obtained by kneading the component R, the plasticizer P, and other necessary components at a temperature below the vulcanization temperature. Examples of the apparatus for kneading the raw material components include conventionally known kneading apparatuses such as a mixer, a Banbury mixer, a kneader mixer, and an open roll.

[0084] 3. Characteristics of the composition (Mooney viscosity of unvulcanized product) For the composition according to one embodiment of the present invention, based on JIS K 6300-1, the Mooney viscosity measured at a preheating time of 1 minute, a rotation time of 4 minutes, and a test temperature of 100 °C using an L-type rotor is preferably 100 or less, more preferably less than 90, and even more preferably less than 80. The Mooney viscosity is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and may be within the range between any two of the values exemplified herein. The Mooney viscosity may also be less than 100.

[0085] (Scorch time of unvulcanized product) The composition according to one embodiment of the present invention preferably has a scorch time measured by a Mooney scorch test at 125°C of 7 minutes or more, more preferably 9 minutes or more, and even more preferably 11 minutes or more, based on JIS K 6300-1. The scorch time is, for example, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 minutes, and may be within the range between any two of the numerical values exemplified herein.

[0086] (Tensile strength of vulcanized molded article) The composition according to one embodiment of the present invention preferably has a tensile strength measured based on JIS K 6251 of 21.0 MPa or more, more preferably 22.5 MPa or more, and even more preferably 24.0 MPa or more, for the vulcanizate obtained by molding based on JIS K6299. The tensile strength is, for example, 21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0, 30.0 MPa, and may be within the range between any two of the numerical values exemplified herein.

[0087] (Cold resistance of vulcanized molded article) The composition according to one embodiment of the present invention preferably has a T10 of less than -10°C, more preferably less than -20°C, and even more preferably less than -30°C, for the vulcanizate obtained by vulcanizing the composition based on JIS K6299, as determined by a Gehman torsional test based on JIS K 6261. T10 is, for example, -40, -35, -30, -25, -20, -15°C, less than -10°C, and may be within the range between any two of the numerical values exemplified herein.

[0088] (Water resistance of vulcanized molded article) The composition according to one embodiment of the present invention is obtained by immersing the vulcanizate obtained by molding based on JIS K6299 in water at 70°C for 144 hours, and the volume change rate ΔV calculated based on JIS K 6258 is, for example, less than 0, 1, 2, 3, 4, 5, 6, 7, 8%, and 9%, and may be within the range between any two of the numerical values exemplified herein.

[0089] (Acid resistance of vulcanized molded article) For the composition according to one embodiment of the present invention, the vulcanizate obtained by molding based on JIS K6299 is immersed in 10% hydrochloric acid at 70 ° C for 144 hours, and the volume change rate ΔV calculated based on JIS K 6258 is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9%, and less than 10%, and may be within the range between any two of the numerical values exemplified herein.

[0090] (Alkali resistance of vulcanized molded article) For the composition according to one embodiment of the present invention, the vulcanizate obtained by molding based on JIS K6299 is immersed in 10% hydrochloric acid at 70 ° C for 144 hours, and the volume change rate ΔV calculated based on JIS K 6258 is, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9%, and less than 10%, and may be within the range between any two of the numerical values exemplified herein.

[0091] (Oil resistance of vulcanized molded article) For the composition according to one embodiment of the present invention, the vulcanizate obtained by molding based on JIS K6299 is immersed in a test oil (automobile high lubricating oil, ASTM No. 3, IRM 903 oil) at 130 ° C for 72 hours, and the volume change rate ΔV calculated based on JIS K 6258 is, for example, 0, 5, 10, 15, 20, 25, 30, 35%, and less than 40%, and may be within the range between any two of the numerical values exemplified herein.

[0092] (Wear resistance (volume change during 1000 revolutions)) For the composition according to one embodiment of the present invention, the obtained composition is press-vulcanized under the conditions of 160 ° C × 40 minutes to produce a vulcanized molded article having a diameter of 63.6 mm, a thickness of 12.7 mm, and a central hole of 12.7 mm. For the obtained vulcanized molded article, an Akron wear test (1000 revolutions of wear, ΔV, unit: mm 3 ) is carried out, and the wear during 1000 revolutions is, for example, for example, 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mm 3 , and 110 mm 3It may be less than and within the range between any two of the numerical values exemplified herein.

[0093] 4. Unvulcanized molded body, vulcanizate, and vulcanized molded body The unvulcanized molded body according to the present embodiment uses the composition according to the present embodiment and is a molded body (molded product) of the composition (in an unvulcanized state) according to the present embodiment. The method for manufacturing the unvulcanized molded body according to the present embodiment includes a step of molding the composition (in an unvulcanized state) according to the present embodiment. The unvulcanized molded body according to the present embodiment is composed of the composition (in an unvulcanized state) according to the present embodiment.

[0094] The vulcanizate according to the present embodiment is a vulcanizate of the composition according to the present embodiment. The method for manufacturing the vulcanizate according to the present embodiment includes a step of vulcanizing the composition according to the present embodiment.

[0095] The vulcanized molded body according to the present embodiment is a vulcanized molded body of the composition according to the present embodiment. The vulcanized molded body according to the present embodiment uses the vulcanizate according to the present embodiment and is a molded body (molded product) of the vulcanizate according to the present embodiment. The vulcanized molded body according to the present embodiment is composed of the vulcanizate according to the present embodiment.

[0096] The vulcanized molded body according to the present embodiment can be obtained by molding the vulcanizate obtained by vulcanizing the composition (in an unvulcanized state) according to the present embodiment, and can also be obtained by vulcanizing the molded body obtained by molding the composition (in an unvulcanized state) according to the present embodiment. The vulcanized molded body according to the present embodiment can be obtained by vulcanizing the composition according to the present embodiment after or during molding. The method for manufacturing the vulcanized molded body according to the present embodiment includes a step of molding the vulcanizate according to the present embodiment or a step of vulcanizing the unvulcanized molded body according to the present embodiment.

[0097] The unvulcanized molded article, vulcanizate, 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. The composition according to the present invention is excellent in the Mooney viscosity of the unvulcanized material and has a sufficiently long scorch time, so it has excellent processability. Since the vulcanizate has well-balanced acid resistance, water resistance, mechanical properties, and cold resistance, it can be used as various members that require these properties. Furthermore, according to the composition according to one embodiment of the present invention, a vulcanizate excellent in alkali resistance, oil resistance, and abrasion resistance can also be obtained, and it can be used as various members that require these properties. The composition 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 as rubber parts such as rubber members for automobiles (for example, sealing materials for automobiles), hose materials, rubber moldings, gaskets, rubber rolls, industrial cables, industrial conveyor belts, and sponges. In particular, it can be used as a member used in an environment where acid resistance and / or water resistance are required. As an example, the composition according to one embodiment of the present invention can be suitably used as a rubber roll. As an example, the vulcanized molded article according to one embodiment of the present invention can be suitably used for rolls for steel that particularly require acid resistance. Further, the vulcanized molded article according to one embodiment of the present invention can be suitably used as a roll for paper making that particularly requires water resistance.

[0098] (Rubber member for automobile) Automotive rubber components include gaskets, oil seals, and packings, etc. They are parts that prevent leakage of liquids and gases, as well as dust and foreign objects such as rainwater and dirt from entering the interior in machines and devices. Specifically, there are gaskets used for fixed applications, and oil seals and packings used for moving parts and movable parts. In the case of gaskets where the sealing part is fixed with bolts, various materials are used for soft gaskets such as O-rings and rubber sheets according to the purpose. Also, packings are used for rotating parts such as the shafts of pumps and motors, the movable parts of valves, reciprocating parts such as pistons, connection parts of couplings, and water stop parts of faucets. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of these components while maintaining the processability of the unvulcanized material. Thereby, it is possible to manufacture seals used in harsh environments, which was difficult with conventional compositions.

[0099] (Hose material) The hose material is a bendable tube. Specifically, there are water supply hoses, oil supply hoses, air supply hoses, steam hoses, high- and low-pressure hydraulic hoses, etc. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of the hose material while maintaining the processability of the unvulcanized material. Thereby, for example, it is possible to manufacture hose materials used in harsh environments, which was difficult with conventional compositions.

[0100] (Rubber molded product) Rubber molded products include vibration isolation rubbers, vibration damping materials, boots, etc. Vibration isolation rubbers and vibration damping materials are rubbers that prevent the transmission and spread of vibrations. Specifically, there are torsional dampers, engine mounts, muffler hangers, etc. that absorb vibrations during engine operation of automobiles and various vehicles to prevent noise. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of vibration isolation rubbers and vibration damping materials. Thereby, it is possible to manufacture vibration isolation rubbers and vibration damping materials that can be used even in harsh environments, which was difficult with conventional compositions. Also, the boot is a bellows-shaped member whose outer diameter gradually increases from one end to the other end. Specifically, there are boots for constant velocity joint covers, boots for ball joint covers (dust cover boots), boots for rack and pinion gears, etc., for protecting drive parts such as automotive drive systems. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of the boots. Thereby, it is possible to manufacture boots that are used in harsher environments than conventional compositions.

[0101] (such as gaskets) Gaskets, oil seals, and packings are parts that prevent leakage of liquids and gases, and entry of dust and foreign substances such as rainwater and dust into machines and devices. Specifically, there are gaskets used for fixed applications, and oil seals and packings used for moving parts and movable parts. For gaskets whose sealing parts are fixed with bolts, various materials are used according to the purpose, as opposed to soft gaskets such as O-rings and rubber sheets. Also, packings are used for rotating parts such as the shafts of pumps and motors, movable parts of valves, reciprocating parts such as pistons, connection parts of couplings, and water stop parts of faucets. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of these members. Thereby, it is possible to manufacture seals that can be used even in harsh environments that were difficult with conventional compositions.

[0102] (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. For rubber rolls, rubber materials such as NBR, EPDM, and CR are used according to the required characteristics for various applications such as paper manufacturing, various metal manufacturing, film manufacturing, printing, general industrial use, agricultural implements such as rice hulling, and food processing. Since CR has good mechanical strength that can withstand the friction of the conveyed object, it is used in a wide range of rubber roll applications. On the other hand, rubber rolls used in environments where they come into contact with oil or water, such as during the manufacture of industrial materials and products for iron and paper manufacturing, have insufficient oil and water resistance and require improvement. Also, when products are plated or during the process of washing products, they may be exposed to acids or alkalis such as gold, silver, nickel, chromium, and zinc, and resistance to these is also required. Furthermore, rubber rolls for conveying heavy objects have the problem of deforming under load and require improvement. The composition of the present invention can enhance the water resistance, acid resistance, and tensile strength of rubber rolls. Thereby, it becomes possible to manufacture rubber rolls used in processes of being immersed or coming into contact with water or acid, which was difficult with conventional compositions.

[0103] (Industrial cable) An industrial cable is a linear member for transmitting electrical or optical signals. It is 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 composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of industrial cables. Thereby, it becomes possible to manufacture industrial cables that can be used even in harsh environments, which was difficult with conventional compositions.

[0104] (Industrial conveyor belt) Industrial conveyor belts include rubber, resin, and metal belts, which are selected according to a variety of usage methods. Among these, rubber conveyor belts are inexpensive and widely used. However, when used in an environment with a lot of friction and collision with the conveyed objects, damage due to deterioration has occurred. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of industrial conveyor belts. Thereby, it is possible to manufacture industrial conveyor belts used in harsh environments that were difficult with conventional compositions.

[0105] (Sponge) A sponge is a porous substance with innumerable fine pores inside. Specifically, it is used in anti-vibration members, sponge seal parts, wet suits, shoes, etc. The composition of the present invention can enhance the acid resistance, water resistance, mechanical properties, and cold resistance of sponges. In addition, since chloroprene rubber is used, it is also possible to enhance the flame retardancy of sponges. Thereby, it is possible to manufacture sponges used in harsh environments that were difficult with conventional compositions, or sponges with excellent flame retardancy. Furthermore, the hardness of the sponge obtained by adjusting the content of the foaming agent and the like can also be appropriately adjusted.

[0106] Examples of the method for molding the composition (unvulcanized state) and the vulcanizate according to the present embodiment include press molding, extrusion molding, calender molding, etc. The temperature for vulcanizing the composition may be appropriately set according to the composition of the composition, and may be 140 to 220 °C, or 160 to 190 °C. The vulcanization time for vulcanizing the composition may be appropriately set according to the composition of the composition, the shape of the unvulcanized molded body, etc.

Examples

[0107] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto.

[0108] (Example 1) (Manufacturing method of chloroprene rubber (R-2)) Into a polymerization kettle with an internal volume of 3 L equipped with a heating and cooling jacket and a stirrer, 24 parts by mass of chloroprene (monomer), 24 parts by mass of acrylonitrile (monomer), 0.5 part by mass of diethylxanthogen disulfide, 200 parts by mass of pure water, 5.00 parts by mass of potassium rosinate (manufactured by Harima Kasei Co., Ltd.), 0.40 part by mass of sodium hydroxide, and 2.0 parts by mass of sodium salt of β-naphthalene sulfonic acid formalin condensate (manufactured by Kao Corporation) were added. Next, 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and then emulsion polymerization was carried out at a polymerization temperature of 40 °C under a nitrogen stream. The above-mentioned chloroprene was added dropwise starting from 20 seconds after the start of polymerization. The dropwise addition flow rate was adjusted with a solenoid valve based on the heat quantity change of the refrigerant during the first 10 seconds from the start of polymerization, and the flow rate was readjusted every 10 seconds thereafter to perform continuously. When the polymerization rate reached 50% with respect to the total amount of chloroprene and acrylonitrile, 0.02 part by mass of phenothiazine, which is 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 latex (R-2) containing a chloroprene-acrylonitrile copolymer.

[0109] The above-mentioned polymerization rate [%] of the chloroprene-based latex was calculated from the dry mass when the chloroprene-based latex was air-dried. Specifically, it was calculated from the following formula (A). In the formula, the "solid content concentration" is the concentration [mass%] of the solid content obtained by heating 2 g of the sampled chloroprene-based latex at 130 °C to remove volatile components such as the solvent (water), volatile chemicals, and raw materials. The "total charged amount" is the total amount [g] of raw materials, reagents, and solvent (water) charged into the polymerization kettle from the start of polymerization to a certain time. The "evaporation residue" is the mass [g] of the chemicals that do not volatilize under the condition of 130 °C and remain as solid content together with the polymer among the chemicals and raw materials charged from the start of polymerization to a certain time. The "charged amount of monomers" is the total amount [g] of the monomers initially charged into the polymerization kettle and the monomers added dropwise from the start of polymerization to a certain time. Here, the "monomers" referred to here is the total amount of chloroprene and acrylonitrile. Polymerization rate = {[(total charged amount × solid content concentration / 100) - evaporation residue] / charged amount of monomers} × 100 ···(A)

[0110] After adjusting the pH of the above-mentioned chloroprene latex (R-2) to 7.0 using acetic acid or sodium hydroxide, the chloroprene latex was frozen and solidified on a metal plate cooled to -20 °C to break the emulsion, thereby obtaining a sheet. After washing this sheet with water, it was dried at 130 °C for 15 minutes to obtain a solid chloroprene rubber (R-2).

[0111] After preparing the above-mentioned chloroprene rubber into a solution with a sample-adjusted concentration of 0.1% by mass using THF, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the chloroprene rubber were measured by a high-speed GPC device (TOSOH HLC-8320GPC: manufactured by Tosoh Corporation) (in terms of standard polystyrene conversion). At that time, a TSK guard column HHR-H was used as the pre-column, and three HSKgel GMHHR-H were used as the analytical columns. The sample pump pressure was 8.0 - 9.5 MPa, the flow rate was 1 mL / min, and it was eluted at 40 °C and detected with a differential refractometer.

[0112] The elution time and molecular weight were obtained using a calibration curve prepared by measuring a total of 9 standard polystyrene samples with known molecular weights 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

[0113] The weight-average molecular weight (Mw) of the chloroprene rubber was 473×10 3 g / mol, the number-average molecular weight (Mn) was 138×10 3 g / mol, and the molecular weight distribution (Mw / Mn) was 3.4.

[0114] The content of the monomer unit of acrylonitrile contained in the chloroprene rubber (R-2) was calculated from the nitrogen atom content in the chloroprene-acrylonitrile copolymer rubber. Specifically, using an elemental analyzer (Sumigraph 220F: manufactured by Sumitomo Chemical Analysis Center Co., Ltd.), the nitrogen atom content in 100 mg of the chloroprene rubber (R-2) was measured, and the content of the monomer unit of acrylonitrile was calculated. The content of the monomer unit of acrylonitrile was 10.0% by mass.

[0115] The above elemental analysis was performed as follows. The electric furnace temperature was set at 900 °C for the reactor, 600 °C for the reduction furnace, 70 °C for the column temperature, and 100 °C for the detector temperature. 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. The calibration curve was prepared using aspartic acid (10.52%) with a known nitrogen content as a standard substance. The content of the monomer unit of acrylonitrile in the chloroprene rubber (R-2) obtained by the above production method was 10.0% by mass.

[0116] <Production method of chloroprene rubbers (R-1, R-3 to R-5)> The addition amount of the acrylonitrile monomer in the polymerization step was changed to obtain a chloroprene rubber (R-1) with a content of the monomer unit of acrylonitrile of 5.0% by mass, a chloroprene rubber (R-3) with a content of the monomer unit of acrylonitrile of 20.0% by mass, a chloroprene rubber (R-4) with a content of the monomer unit of acrylonitrile of 25.0% by mass, and a rubber (R-5) with a content of the monomer unit of acrylonitrile of 0.0% by mass.

[0117] <Preparation of composition> As shown in Tables 1 to 3, the compositions of the examples and comparative examples were obtained by mixing the respective components and kneading them with an 8-inch open roll.

[0118] Each component used to obtain the composition is as follows. Component R: ·R-1 (chloroprene-acrylonitrile copolymer, AN (acrylonitrile monomer unit) content 5% by mass) ·R-2 (chloroprene-acrylonitrile copolymer, AN content 10% by mass) ·R-3 (chloroprene-acrylonitrile copolymer, AN content 20% by mass) ·R-4 (chloroprene-acrylonitrile copolymer, AN content 25% by mass) ·R-5 (mercaptan-modified chloroprene rubber (homopolymer of chloroprene), "S-40V" manufactured by Denka Co., Ltd.) ·R-6 (hydrogenated acrylonitrile-butadiene rubber, Zetpol 2010 manufactured by Nippon Zeon Co., Ltd., bound acrylonitrile content 36%) ·R-7 (acrylonitrile-butadiene rubber, N230S manufactured by JSR Corporation, bound acrylonitrile content 35%) ·R-8 (chlorosulfonated polyethylene, TOSO-CSM manufactured by Tosoh Corporation) ·R-9 (natural rubber, SMR-CV60 manufactured by HB Chemical Corporation)

[0119] Plasticizer P2-A: Bisphenol A type liquid epoxy resin with the following structure (weight average molecular weight: 650)

[0120]

Chemical formula

[0121] Plasticizer P2-B: Bisphenol A type liquid epoxy resin with the following structure (JER-828 manufactured by Mitsubishi Chemical Corporation) (weight average molecular weight: 350)

[0122]

Chemical formula

[0123] Plasticizer P2-C: YS Resin LP (manufactured by Yasuhara Chemical Co., Ltd., CAS: 64536-06-7) (weight average molecular weight: 240)

[0124] [Chemical formula] (Coupling product and polymer of the above compound)

[0125] Plasticizer D: A diene polymer having an epoxy group with the following structure (weight average molecular weight: 1300)

[0126] [Chemical formula]

[0127] Plasticizer E: An ether ester compound, manufactured by ADEKA CORPORATION, Adeka Sizer RS-700 Plasticizer P2-F: Bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation, JER-807) (molecular weight: 230) Plasticizer P1-G: An alicyclic epoxy resin with the following structure (manufactured by Daicel Corporation, Celoxide 2021P) (molecular weight: 250)

[0128] [Chemical formula]

[0129] Hardening agent: Dicarboxylic acid dihydrazide, manufactured by Otsuka Chemical Co., Ltd., isophthalic acid dihydrazide Vulcanizing agent: Zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd., two types of zinc oxide Vulcanizing agent: Organic peroxide, 1,4-bis[(t-butylperoxy) isopropyl] benzene, manufactured by NOF Corporation, Perbutyl P Acid acceptor: Hydrotalcite: Chemical formula Mg3ZnAl2(OH) 12 CO3·3H2O, manufactured by Kyowa Chemical Industry Co., Ltd., ZHT-4A Filler: Carbon black (HAF), "Asahi #70" manufactured by Asahi Carbon Co., Ltd. Filler: Silica, Nipsil AQ manufactured by Tosoh Silica Corporation Silane coupling agent: Methacryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503 Processing Aid: Stearic Acid: Manufactured by Shin Nippon Rika Co., Ltd., Stearic Acid 50S Heat Aging Inhibitor: 4,4'-Bis(α,α-dimethylbenzyl)diphenylamine, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Nocrac CD Ozone Aging Inhibitor: 3,9-Di(3-cyclohexen-1-yl)-2,4,8,10-tetraoxaspiro[5.5]undecane, manufactured by Rancess Co., Ltd., Bulcazon AFS Vulcanization Retarder: 2,2'-Methylenebis(6-tert-butyl-p-cresol), manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Nocrac NS-6

[0130] <Evaluation of the Composition (Unvulcanized Material)> (Measurement of Mooney Viscosity) For the composition (unvulcanized material), the Mooney viscosity was measured in accordance with JIS K 6300-1 at a preheating time of 1 minute, a rotation time of 4 minutes, and a test temperature of 100°C using an L-type rotor. A: Less than 80 B: 80 or more and less than 90 C: 90 or more and less than 100 D: 100 or more

[0131] (Scorch Time) Based on JIS K 6300-1, a Mooney scorch test was carried out at a test temperature of 125°C using an L-type rotor. The time when the measured Mooney viscosity increased by 5 M was defined as the scorch time. The obtained scorch time was evaluated according to the following evaluation criteria. A: 11 minutes or more B: 9 minutes or more and less than 11 minutes C: 7 minutes or more and less than 9 minutes D: Less than 7 minutes

[0132] <Preparation of Vulcanized Molded Body> The obtained composition was press-vulcanized under the conditions of 160°C × 40 minutes based on JIS K6299 to prepare a sheet-like vulcanized molded body with a thickness of 2 mm.

[0133] <Evaluation of Vulcanized Molded Body> The evaluation of the above-mentioned vulcanized molded body was carried out as follows. The results are shown in Table 1 and Table 2.

[0134] (Tensile strength) Based on JIS K 6251, the above-mentioned sheet-shaped vulcanized molded body was molded into dumbbell-shaped No. 3 test pieces with a thickness of 2 mm, and five test pieces were prepared. Using a long-stroke tensile test system for vulcanized rubber manufactured by Shimadzu Corporation, the tensile strength of each test piece was measured at a tensile speed of 500 mm / min. The obtained tensile strength was evaluated according to the following evaluation criteria. A: 24.0 MPa or more B: 22.5 MPa or more and less than 24.0 MPa C: 21.0 MPa or more and less than 22.5 MPa D: Less than 21.0 MPa

[0135] (Cold resistance) Based on JIS K 6261, a German torsion test was performed to obtain T10. For the above-mentioned vulcanized molded body, the temperature (T10) at which the 180° torsion modulus becomes 10 times the 180° torsion modulus at room temperature was obtained. The obtained T10 was evaluated according to the following criteria. A: Less than -30°C B: -30°C or more and less than -20°C C: -20°C or more and less than -10°C D: -10°C or more

[0136] (Water resistance (volume change rate after immersion in water at 70°C for 144 h)) Test pieces were obtained by punching out test pieces with a length of 25 mm and a width of 20 mm from the above-mentioned vulcanized molded body. The obtained test pieces were immersed in water at 70°C for 144 hours. The volume change rate ΔV was calculated in accordance with JIS K 6258. The obtained volume change rate ΔV was evaluated according to the following criteria. A: Less than 3% B: 3% or more and less than 6% C: 6% or more and less than 9% D: 9% or more

[0137] (Acid resistance (volume change rate after immersion in 10% hydrochloric acid at 70°C for 144 h)) Test specimens were obtained by punching out test pieces measuring 25 mm in length and 20 mm in width from the above-mentioned vulcanized molded body. The obtained test pieces were immersed in 10% hydrochloric acid at 70 °C for 144 hours. The volume change rate ΔV was calculated in accordance with JIS K 6258. The obtained volume change rate ΔV was evaluated according to the following criteria. A: Less than 4% B: 4% or more and less than 7% C: 7% or more and less than 10% D: 10% or more

[0138] (Alkali resistance (volume change rate after immersion in 10% sodium hydroxide aqueous solution at 70 °C for 144 h)) Test specimens were obtained by punching out test pieces measuring 25 mm in length and 20 mm in width from the above-mentioned vulcanized molded body. The obtained test pieces were immersed in 10% sodium hydroxide aqueous solution at 70 °C for 144 hours. The volume change rate ΔV was calculated in accordance with JIS K 6258. The obtained volume change rate ΔV was evaluated according to the following criteria. A: Less than 2% B: 2% or more and less than 5% C: 5% or more and less than 8% D: 8% or more

[0139] (Oil resistance (volume change rate after immersion in IRM-903 at 130 °C for 72 h)) Test specimens were obtained by punching out test pieces measuring 25 mm in length and 20 mm in width from the above-mentioned vulcanized molded body. The obtained test pieces were immersed in test oil (automotive high lubricating oil, ASTM No. 3, IRM 903 oil) at 130 °C for 72 hours. The volume change rate ΔV was calculated in accordance with JIS K 6258. The obtained volume change rate was evaluated according to the following evaluation criteria. A: Less than 25% B: 25% or more and less than 30% C: 30% or more and less than 40% D: 40% or more

[0140] (Wear resistance (volume change during 1000 revolutions)) The obtained composition was press-vulcanized under the conditions of 160 °C for 40 minutes to prepare 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. Regarding the obtained vulcanized molded body, an Akron abrasion test (1000 abrasions, ΔV, unit: mm 3 ) was carried out. 110 mm 3 Those showing the following values were judged to be good. A: Less than 50 mm 3 B: 50 mm or more and less than 90 mm 3 3 C: 90 mm or more and less than 110 mm 3 3 D: 110 mm or more 3

[0141]

Table 1

[0142]

Table 2

[0143]

Table 3

[0144]

Table 4

[0145]

Table 5

[0146]

Table 6

Claims

1. A composition comprising at least one component R selected from chloroprene rubber, hydrogenated acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber, and natural rubber, wherein the content rate of the unsaturated nitrile monomer unit is less than 25% by mass, and a plasticizer P, the composition contains 0.1 to 25 parts by mass of the plasticizer P with respect to 100 parts by mass of the component R, the plasticizer P has a weight average molecular weight of 150 to 800, the plasticizer P is at least one selected from an alicyclic epoxy resin P1 and a plasticizer P2 having no ester group, the composition contains 0.1 to 15 parts by mass of hydrotalcite with respect to 100 parts by mass of the component R, the composition contains 0.3 to 1.8 parts by mass of an organic peroxide with respect to 100 parts by mass of the component R, Composition.

2. The composition according to claim 1, wherein the unsaturated nitrile monomer unit is a monomer unit derived from acrylonitrile.

3. The composition according to claim 1 or claim 2, which contains 20 to 80 parts by mass of a filler with respect to 100 parts by mass of the component R.

4. The composition according to claim 1 or claim 2, wherein the plasticizer P2 having no ester group contains at least one plasticizer selected from bisphenol A type liquid epoxy resin and bisphenol F type liquid epoxy resin.

5. The composition according to claim 1 or claim 2, which contains 1 part by mass or more of at least one compound selected from carboxylic acid hydrazide and carboxylic acid dihydrazide with respect to 100 parts by mass of the plasticizer P2 having no ester group.

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

7. A vulcanized molded article containing the vulcanizate according to claim 6.

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