Rubber composition and organopolysiloxane

Abstract

To provide a rubber composition which is excellent in vulcanization characteristics and in tensile characteristics, wet grip properties and low rolling resistance after vulcanization and can achieve a desired low fuel consumption tire.SOLUTION: The rubber composition contains an organopolysiloxane represented, e.g., by the following average composition formula (1) and having a mercapto group-containing organic group and either or both of a trialkoxysilyl group-containing organic group and a dialkoxymethylsilyl group-containing organic group. (A)a(B)b(C)c(D)dSiO(4-a-b-c-d) / 2 (1) (A represents a mercapto group-containing organic group; B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl group-containing organic group; C represents a hydrolyzable group; D represents a C1-12 alkyl group, a C1-10 haloalkyl group or a C6-12 aryl group; and a, b, c and d represent numbers satisfying 0<a<1, 0<b<1, 0<c<3, 0≤d<1 and 0<a+b+c+d<4).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a rubber composition and an organopolysiloxane, and more specifically to a rubber composition containing an organopolysiloxane containing a mercapto group-containing organic group and a trialkoxysilyl group or a dialkoxymethylsilyl group. [Background technology]

[0002] Tires made of silica-filled rubber compositions have excellent performance in automotive applications, particularly in terms of abrasion resistance, rolling resistance, and wet grip. Improvements in these performances are closely related to improvements in tire fuel economy, and therefore have been the subject of intensive research in recent years.

[0003] In order to improve fuel economy, it is essential to increase the silica filling rate of the rubber composition, but although silica-filled rubber compositions reduce the rolling resistance of tires and improve wet grip performance, they have problems with workability because they have high unvulcanized viscosity and require multi-stage kneading, etc. Therefore, rubber compositions in which an inorganic filler such as silica is simply blended suffer from insufficient dispersion of the filler, resulting in significant reductions in breaking strength and abrasion resistance. Therefore, sulfur-containing organosilicon compounds are essential to improve the dispersibility of inorganic fillers in rubber and to chemically bond the inorganic fillers to the rubber matrix.

[0004] As sulfur-containing organosilicon compounds, compounds containing an alkoxysilyl group and a polysulfide silyl group in the molecule, such as bis-triethoxysilylpropyl tetrasulfide and bis-triethoxysilylpropyl disulfide, are known to be effective (see Patent Documents 1 to 4). In addition to the above-mentioned organosilicon compounds having polysulfide groups, the use of thioester-type organosilicon compounds containing blocked mercapto groups, which are advantageous for silica dispersibility, and sulfur-containing organosilicon compounds in which an amino alcohol compound is transesterified with a hydrolyzable silyl group moiety, which is advantageous for affinity with silica through hydrogen bonding, are also known (see Patent Documents 5 to 9).

[0005] However, even when the sulfur-containing organosilicon compounds disclosed in the above-mentioned patent documents are used, it has not yet been possible to obtain a rubber composition for a tire that achieves the desired fuel economy. Furthermore, these sulfur-containing organosilicon compounds are more expensive than sulfide-type compounds, and the production methods are complicated, resulting in productivity problems, and various other issues remain.

[0006] Furthermore, Patent Document 10 discloses a rubber composition for tires that uses a polysiloxane having a mercapto group and a long-chain alkyl group. However, although tires obtained from this composition have improved rolling resistance and wet grip properties, they have the problem of significantly deteriorating vulcanization characteristics. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2004-525230 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-18511 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-145890 [Patent Document 4] U.S. Patent No. 6,229,036 [Patent Document 5] Japanese Patent Application Laid-Open No. 2005-8639 [Patent Document 6] Japanese Patent Application Laid-Open No. 2008-150546 [Patent Document 7] Japanese Patent Application Laid-Open No. 2010-132604 [Patent Document 8] Patent No. 4571125 [Patent Document 9] U.S. Patent No. 6,414,061 [Patent Document 10] Patent No. 5339008 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and provides a rubber composition excellent in vulcanization characteristics, tensile characteristics after vulcanization, wet grip properties, and low rolling resistance, and capable of realizing a desired low fuel consumption tire, and an organopolysiloxane that imparts the above characteristics when added to the rubber composition.

Means for Solving the Problems

[0009] As a result of intensive studies to achieve the above object, the present inventors have found that a rubber composition containing an organopolysiloxane containing a mercapto group-containing organic group and a trialkoxysilyl group or a dialkoxymethylsilyl group can improve vulcanization characteristics, tensile characteristics after vulcanization, wet grip properties, and rolling resistance, and have found that a tire made of this rubber composition can realize low fuel consumption tire characteristics, thus completing the present invention.

[0010] That is, the present invention provides 1. A rubber composition containing an organopolysiloxane having a mercapto group-containing organic group and a trialkoxysilyl group-containing organic group, a dialkoxymethylsilyl group-containing organic group, or both. 2. The rubber composition according to 1, wherein the organopolysiloxane is represented by the following average compositional formula (1). (A) , , , , (4-a-b-c-d) / 2 , c , d , a , b (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1) (In the formula, A represents a mercapto group-containing organic group, B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl-containing organic group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and a, b, c, and d represent numbers satisfying 0 < a < 1, 0 < b < 1, 0 < c < 3, 0 ≤ d < 1, and 0 < a + b + c + d < 4.) 3. The rubber composition according to 2, wherein the mercapto group-containing organic group is represented by the following formula (2) * -(CH2) m -SH (2) (where m represents an integer from 1 to 10, * - represents a bond.) and is represented by the formula, and the trialkoxysilyl group-containing organic group or dialkoxymethylsilyl-containing organic group is represented by the following formula (3) * -(CH2) m -S-(CH2) n -Si(CH3) 3-k (OR 1 ) k (3) (where m represents an integer from 1 to 10, n represents an integer from 1 to 10, k represents 2 or 3, and R 1 each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an alkenyl group having to 10 carbon atoms, * - represents a bond.) and is represented by the formula, and the hydrolyzable group is represented by the following formula (4) * -OR 1 (4) (where R 1 represents the same meaning as described above, * - represents a bond.) A rubber composition represented by 2, 4. A rubber composition of 2 or 3 in which d satisfies 0 < d < 1, 5. An organopolysiloxane represented by the following average composition formula (1’) (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1’) (In the formula, A represents a mercapto group-containing organic group, B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl group-containing organic group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, and a, b, c, and d represent numbers satisfying 0 < a < 1, 0 < b < 1, 0 < c < 3, 0 < d < 1, and 0 < a + b + c + d < 4.) provides.

Effects of the Invention

[0011] The rubber composition of the present invention is excellent in vulcanization characteristics, tensile properties after vulcanization, wet grip properties, and low rolling resistance, and a tire formed using this rubber composition can achieve low fuel consumption tire characteristics.

Modes for Carrying Out the Invention

[0012] Hereinafter, the present invention will be specifically described. [1] Organopolysiloxane The organopolysiloxane blended in the rubber composition of the present invention has a mercapto group-containing organic group and a trialkoxysilyl group-containing organic group, a dialkoxymethylsilyl group-containing organic group or both, and specifically, an organopolysiloxane represented by the following average composition formula (1) is preferable. (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1)

[0013] In formula (1), A represents a mercapto group-containing organic group, B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl-containing organic group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, and a, b, c, and d represent numbers satisfying 0 < a < 1, 0 < b < 1, 0 < c < 3, 0 ≦ d < 1, preferably 0 < d < 1, and 0 < a + b + c + d < 4. From the viewpoints of the dispersibility of silica and rubber physical properties, a, b, c, and d are more preferably numbers satisfying 0.05 ≦ a ≦ 0.80, 0.10 ≦ b ≦ 0.9, 1 ≦ c ≦ 2.5, 0 < d ≦ 0.6, and even more preferably numbers satisfying 0.1 ≦ a ≦ 0.7, 0.2 ≦ b ≦ 0.8, 1 ≦ c ≦ 2.5, 0.05 ≦ d ≦ 0.5. Note that a, b, c, and d represent the average number of moles of each organic group per mole of silicon atom.

[0014] More specifically, in formula (1), the mercapto group-containing organic group is represented by the following formula (2) * -(CH2) m -SH (2) (In the formula, m represents an integer of 1 to 10, * - represents a bond.) and the trialkoxysilyl group-containing organic group or the dialkoxymethylsilyl-containing organic group is represented by the following formula (3) * -(CH2) m -S-(CH2) n -Si(CH3) 3-k (OR 1 ) k (3) (In the formula, m represents an integer of 1 to 10, n represents an integer of 1 to 10, k represents 2 or 3, R 1 each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, * - represents a bond.) and the hydrolyzable group is represented by the following formula (4) * -OR1 (4) (In the formula, R 1 has the same meaning as above, * - indicates a bond.) More preferred is an organopolysiloxane represented by the following formula:

[0015] In the above formulas (3) and (4), R 1 Specific examples of the alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, and octadecyl groups, specific examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, and naphthyl groups, specific examples of the aralkyl group having 7 to 10 carbon atoms include benzyl groups, and specific examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, propenyl, and pentenyl groups.

[0016] In the above formula (1), specific examples of the alkyl group having 1 to 12 carbon atoms represented by D include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, and n-decyl groups. Specific examples of the haloalkyl group having 1 to 10 carbon atoms include 1-chloromethyl, 3-chloropropyl, 6-chlorohexyl, 8-chlorooctyl, 1-bromomethyl, 3-bromopropyl, 6-bromohexyl, and 8-bromooctyl groups. Specific examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, styryl, naphthyl, and diphenyl groups. Among these, n-octyl groups are preferred from the viewpoints of raw material availability and rubber physical properties. Furthermore, the inclusion of a unit containing D in the organopolysiloxane improves the dispersibility of silica and improves rubber physical properties.

[0017] Specific examples of the mercapto group-containing organic group represented by the above formula (2) include the groups shown below. * -CH2SH * -C2H4SH * -C3H6SH * -C4H8SH *-C5H 10 SH * -C6H 12 SH * -C7H 14 SH * -C8H 16 SH * -C9H 18 SH * -C 10 H 20 SH (In the formula, * - indicates a bond. The same applies below.)

[0018] Specific examples of the trialkoxysilyl group-containing organic group or dialkoxymethylsilyl group-containing organic group represented by the above formula (3) include the groups shown below. * -C3H6-S-C2H4-Si(OCH3)3 * -C3H6-S-C2H4-SiCH3(OCH3)2 * -C3H6-S-C2H4-Si(OC2H5)3 * -C3H6-S-C2H4-SiCH3(OC2H5)2 * -C3H6-S-C6H 12 -Si(OCH3)3 * -C3H6-S-C6H 12 -SiCH3(OCH3)2 * -C3H6-S-C6H 12 -Si(OC2H5)3 * -C3H6-S-C6H 12 -SiCH3(OC2H5)2 * -C3H6-S-C8H 16 -Si(OCH3)3 * -C3H6-S-C8H 16 -SiCH3(OCH3)2 * -C3H6-S-C8H 16 -Si(OC2H5)3 * -C3H6-S-C8H 16 -SiCH3(OC2H5)2 * -CH2-S-C2H4-Si(OCH3)3 * -CH2-S-C2H4-SiCH3(OCH3)2 * -CH2-S-C2H4-Si(OC2H5)3 * -CH2-S-C2H4-SiCH3(OC2H5)2 * -CH2-S-C6H 12 -Si(OCH3)3 * -CH2-S-C6H 12 -SiCH3(OCH3)2 * -CH2-S-C6H 12 -Si(OC2H5)3 * -CH2-S-C6H 12 -SiCH3(OC2H5)2 * -CH2-S-C8H 16 -Si(OCH3)3 * -CH2-S-C8H 16 -SiCH3(OCH3)2 * -CH2-S-C8H 16 -Si(OC2H5)3 * -CH2-S-C8H 16 -SiCH3(OC2H5)2

[0019] Specific examples of the hydrolyzable group represented by the above formula (4) include the groups shown below. * -OCH3 * -OC2H5 * -OC3H7 *-OC4H9 * -OC5H 11

[0020] The organopolysiloxane can be produced by reacting a hydrolysis condensation product of a mercapto group-containing organosilicon compound represented by the following formula (5) with an alkenyl group-containing organosilicon compound represented by the following formula (7), or by reacting a co-hydrolysis condensation product of a mercapto group-containing organosilicon compound represented by the following formula (5) and an organosilicon compound represented by the following formula (6) with an alkenyl group-containing organosilicon compound represented by the following formula (7).

[0021] [ka] (In the formula, R 1 and m have the same meaning as above, y represents an integer of 1 to 3, and Me represents a methyl group.

[0022] [ka] (In the formula, R 1 has the same meaning as above, k represents an integer of 0 to 8, z is 2 or 3, and Me represents a methyl group.

[0023] [ka] (In the formula, R 1 has the same meaning as above, and R 3 represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and z represents an integer of 1 to 4.

[0024] In the above formula (6), R 3Specific examples of the alkyl group having 1 to 12 carbon atoms represented by the formula (I) include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, and n-decyl groups, and specific examples of the haloalkyl group having 1 to 10 carbon atoms include 1-chloromethyl, 3-chloropropyl, 6-chlorohexyl, 8-chlorooctyl, 1-bromomethyl, 3-bromopropyl, 6-bromohexyl, and 8-bromooctyl groups, and specific examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, styryl, naphthyl, and diphenyl groups.

[0025] Specific examples of the organosilicon compound represented by the above formula (5) include α-mercaptomethyltrimethoxysilane, α-mercaptomethylmethyldimethoxysilane, α-mercaptomethyltriethoxysilane, α-mercaptomethylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldiethoxysilane.

[0026] Specific examples of the organosilicon compound represented by the above formula (6) include methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, ethyltrimethoxysilane, ethylmethyldimethoxysilane, ethyltriethoxysilane, ethylmethyldiethoxysilane, butyltrimethoxysilane, butylmethyldimethoxysilane, butyltriethoxysilane, butylmethyldiethoxysilane, hexyltrimethoxysilane, hexylmethyldimethoxysilane, hexyltriethoxysilane, hexylmethyldiethoxysilane, and octyltrimethoxysilane. alkyl group-containing organosilicon compounds such as silane, octylmethyldimethoxysilane, octyltriethoxysilane, octylmethyldiethoxysilane, decyltrimethoxysilane, decylmethyldimethoxysilane, decyltriethoxysilane, and decylmethyldiethoxysilane; aryl group-containing organosilicon compounds such as phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryltriethoxysilane, and p-styrylmethyldiethoxysilane;1-Chloromethyltrimethoxysilane, 1-chloromethylmethyldimethoxysilane, 1-chloromethyltriethoxysilane, 1-chloromethylmethyldiethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropylmethyldiethoxysilane, 6-chlorohexyltrimethoxysilane, 6-chlorohexylmethyldimethoxysilane, 6-chlorohexyltriethoxysilane, 6-chlorohexylmethyldiethoxysilane, 8-chlorooctyltrimethoxysilane, 8-chlorooctylmethyldimethoxysilane, 8-chlorooctyltriethoxysilane, 8-chlorooctylmethyldiethoxysilane, 1-bromomethyltrimethoxysilane, 1-bromomethylmethyldimethoxysilane , 1-bromomethyltriethoxysilane, 1-bromomethylmethyldiethoxysilane, 3-bromopropyltrimethoxysilane, 3-bromopropylmethyldimethoxysilane, 3-bromopropyltriethoxysilane, 3-bromopropylmethyldiethoxysilane, 6-bromohexyltrimethoxysilane, 6-bromohexylmethyldimethoxysilane, 6-bromohexyltriethoxysilane, 6-bromohexylmethyldiethoxysilane, 8-bromooctyltrimethoxysilane, 8-bromooctylmethyldimethoxysilane, 8-bromooctyltriethoxysilane, 8-bromooctylmethyldiethoxysilane, and other halogenated alkyl group-containing organosilicon compounds; and tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane.

[0027] Specific examples of the alkenyl group-containing organosilicon compound represented by the above formula (7) include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, allyltrimethoxysilane, allylmethyldimethoxysilane, allyltriethoxysilane, allylmethyldiethoxysilane, hexenyltrimethoxysilane, hexenylmethyldimethoxysilane, hexenyltriethoxysilane, hexenylmethyldiethoxysilane, octenyltrimethoxysilane, octenylmethyldimethoxysilane, octenyltriethoxysilane, octenylmethyldiethoxysilane, and the like.

[0028] The hydrolysis-condensation product of the mercapto group-containing organosilicon compound represented by the above formula (5), or the co-hydrolysis-condensation product of the mercapto group-containing organosilicon compound represented by the above formula (5) and the organosilicon compound represented by the above formula (6), can be produced by a known method using a hydrolysis-condensation catalyst.

[0029] As the hydrolysis / condensation catalyst, various known catalysts can be used. Specific examples thereof include organic acids such as acetic acid, butyric acid, maleic acid, and citric acid; inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, and sulfuric acid; basic compounds such as triethylamine; organic metal salts such as tetrabutyl titanate and dibutyltin dilaurate; and fluorine-containing compounds such as KF and NHF. These may be used alone or in combination. The amount of the catalyst used is preferably in the range of 0.0001 to 1 mol % based on the total amount of the reaction components.

[0030] The amount of water used in the hydrolysis and condensation reaction can be adjusted depending on the desired degree of polymerization, and is usually preferably 0.5 to 0.99 mol, more preferably 0.66 to 0.90 mol, per mol of the total hydrolyzable silyl groups.

[0031] In the hydrolysis-condensation reaction, a solvent may be used as needed. Usable solvents include alcohols such as methanol, ethanol, isopropanol, and t-butanol; ketones such as acetone and methyl isobutyl ketone; ethers such as dibutyl ether; esters such as ethyl acetate; aromatics such as toluene; etc. Among these, alcohols such as methanol and ethanol are preferred.

[0032] The reaction of the hydrolysis condensate of the mercapto group-containing organosilicon compound represented by the above formula (5) or the co-hydrolysis condensate of the mercapto group-containing organosilicon compound represented by the above formula (5) and the organosilicon compound represented by the above formula (6) with the vinyl group-containing organosilicon compound represented by the above formula (7) can be carried out using known ene-thiol reaction techniques.

[0033] In the ene-thiol reaction, a catalyst such as an organic peroxide or an azo compound may be used as needed. Specific examples of organic peroxides include benzoyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, and dicumyl peroxide. Specific examples of azo compounds include 2,2'-azobispropane, 2,2'-dichloro-2,2'-azobispropane, 1,1'-azo(methylethyl) diacetate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile (AIBN), methyl 2,2'-azobis-2-methylpropionate, 2,2'-dichloro-2,2'-azobisbutane, 2,2'-azobis-2-methylbutyronitrile, dimethyl 2,2'-azobisisobutyrate, 3,5-dihydroxymethylphenylazo-2-methylmalonodinitrile, 2,2'-azobis-2-methylvaleronitrile, dimethyl 4,4'-azobis-4-cyanovalerate, and 2,2'-azobis-2,4-dimethylvaleronitrile.

[0034] The amount of catalyst used is preferably 0.00001 to 10 parts by mass per 100 parts by mass of the total amount of the hydrolysis condensate of the mercapto group-containing organosilicon compound represented by the above formula (5) or the co-hydrolysis condensate of the mercapto group-containing organosilicon compound represented by the above formula (5) and the organosilicon compound represented by the above formula (6), and the alkenyl group-containing organosilicon compound represented by the above formula (7).

[0035] In the ene-thiol reaction, a solvent may be used if necessary. Usable solvents include alcohols such as methanol, ethanol, isopropanol, and t-butanol; ketones such as acetone and methyl isobutyl ketone; ethers such as dibutyl ether; esters such as ethyl acetate; aromatics such as toluene; and hydrocarbons such as hexane and decane. The reaction temperature for the ene-thiol reaction is preferably 0 to 200°C, more preferably 50 to 150°C, in order to prevent volatilization of the vinyl group-containing organosilicon compound represented by the above formula (7).

[0036] [2] Rubber composition The rubber composition of the present invention contains the organopolysiloxane (A) and may further contain a diene rubber (B) and a filler (C). Considering the physical properties of the resulting rubber and the balance between the degree of effect exerted and economic efficiency, the amount of the organopolysiloxane (A) blended is preferably 3 to 20 parts by mass, and more preferably 5 to 15 parts by mass, per 100 parts by mass of the filler (C) described below.

[0037] As the diene rubber (B), any rubber commonly used in various rubber compositions can be used, and specific examples thereof include natural rubber (NR); various isoprene rubbers (IR), various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubber (NBR), and other diene rubbers, which may be used alone or in combination of two or more. In addition to diene rubbers, non-diene rubbers such as butyl rubber (IIR) and ethylene-propylene copolymer rubbers (EPR, EPDM) can also be used in combination.

[0038] Examples of the filler (C) include silica, talc, clay, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium oxide, etc. Among these, silica is preferred, and the rubber composition of the present invention is more preferably used as a silica-containing rubber composition. In this case, the amount of filler (C) to be compounded is preferably 5 to 200 parts by mass, more preferably 30 to 120 parts by mass, per 100 parts by mass of diene rubber, taking into consideration the physical properties of the resulting rubber and the balance between the degree of effect exerted and economic efficiency.

[0039] In addition to the components (A) to (C), the rubber composition of the present invention may contain various additives that are generally used in tires and other general rubbers, such as carbon black, vulcanizing agents, crosslinking agents, vulcanization accelerators, crosslinking accelerators, various oils, antioxidants, plasticizers, etc. The amounts of these additives may be conventional amounts as long as they do not deviate from the object of the present invention.

[0040] The rubber composition of the present invention can be obtained by kneading the above components (A) to (C) and, if necessary, other components, according to a conventional method.

[0041] [3] Rubber products (tires) The rubber composition of the present invention can be used to produce rubber products, such as tires, by vulcanizing or crosslinking the rubber composition. In particular, when producing tires, it is preferable that the rubber composition of the present invention is used in the tread.

[0042] A tire obtained using the rubber composition of the present invention has significantly improved rolling resistance performance and wet grip performance, and therefore can achieve the desired low fuel consumption. The tire structure may be a conventionally known structure, and the manufacturing method may be a conventionally known manufacturing method. In the case of a gas-filled tire, the gas to be filled in the tire may be normal air, air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium. [Example]

[0043] The present invention will be explained in more detail below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. In the following Examples, the weight average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0044] [1] Synthesis of organopolysiloxane [Synthesis Example 1-1] A 2 L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 953 g (4.0 mol) of 3-mercaptopropyltriethoxysilane (KBE-803, manufactured by Shin-Etsu Chemical Co., Ltd.) and 100 g of ethanol, and then 54 g of 0.5 N aqueous hydrochloric acid (3.0 mol of water) was added dropwise at 25°C. The mixture was then stirred at 80°C for 10 hours and then cooled to 25°C. 3.0 g of propylene oxide was added dropwise, and the mixture was stirred at 25°C for 1 hour. The reaction solution was evaporated under reduced pressure and filtered to yield 730 g of organopolysiloxane (i) as a colorless, transparent liquid. The resulting organopolysiloxane (i) had a weight-average molecular weight of 730, a mercapto equivalent of 183 g / mol, and was represented by the following average compositional formula: (-C3H6-SH) 1.00 (-OC2H5) 1.50SiO 0.75 (i)

[0045] [Synthesis Example 1-2] A 2 L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 715 g (3.0 mol) of 3-mercaptopropyltriethoxysilane (KBE-803, manufactured by Shin-Etsu Chemical Co., Ltd.), 277 g (1.0 mol) of octyltriethoxysilane (KBE-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), and 100 g of ethanol, and then 54 g of 0.5 N aqueous hydrochloric acid (3.0 mol of water) was added dropwise at 25°C. The mixture was then stirred at 80°C for 10 hours and then cooled to 25°C. 3.0 g of propylene oxide was added dropwise, and the mixture was stirred at 25°C for 1 hour. The reaction solution was evaporated under reduced pressure and filtered, yielding 770 g of organopolysiloxane (ii) as a colorless, transparent liquid. The resulting organopolysiloxane (ii) had a weight average molecular weight of 770, a mercapto equivalent of 256 g / mol, and was represented by the following average composition formula: (-C3H6-SH) 0.75 (-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (ii)

[0046] [Comparative Synthesis Example 1-1] A 2 L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 238 g (1.0 mol) of 3-mercaptopropyltriethoxysilane (KBE-803, manufactured by Shin-Etsu Chemical Co., Ltd.), 831 g (3.0 mol) of octyltriethoxysilane (KBE-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), and 100 g of ethanol, and then 54 g of 0.5 N aqueous hydrochloric acid (3.0 mol of water) was added dropwise at 25°C. The mixture was then stirred at 80°C for 10 hours and then cooled to 25°C. 3.0 g of propylene oxide was added dropwise, and the mixture was stirred at 25°C for 1 hour. The reaction solution was evaporated under reduced pressure and filtered, yielding 840 g of organopolysiloxane (iii) as a colorless, transparent liquid. The resulting organopolysiloxane (iii) had a weight average molecular weight of 850, a mercapto equivalent of 845 g / mol, and was represented by the following average composition formula: (-C3H6-SH)0.25 (-C8H 17 ) 0.75 (-OC2H5) 1.50 SiO 0.75 (iii)

[0047] [Synthesis Example 1-4] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 183 g (1 mole of mercapto groups) of the organopolysiloxane (i) obtained in Synthesis Example 1-1 and 95 g (0.5 moles) of vinyltriethoxysilane (KBE-1003, Shin-Etsu Chemical Co., Ltd.), followed by the addition of 0.1 g of a peroxyester compound (Perbutyl O, NOF Corporation) at 90°C and stirring for 3 hours at 90°C. The reaction solution was evaporated under reduced pressure and filtered to yield 275 g of organopolysiloxane (iv) as a colorless, transparent liquid. The resulting organopolysiloxane (iv) had a weight-average molecular weight of 1100, a mercapto equivalent of 555 g / mol, and was represented by the following average compositional formula: (-C3H6-SH) 0.50 (-C3H6-S-C2H4-Si(OC2H5)3) 0.50 (-OC2H5) 1.50 SiO 0.75 (iv)

[0048] [Synthesis Example 1-5] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 183 g (1 mole of mercapto groups) of the organopolysiloxane (i) obtained in Synthesis Example 1-1 and 143 g (0.75 moles) of vinyltriethoxysilane (KBE-1003, Shin-Etsu Chemical Co., Ltd.), followed by the addition of 0.1 g of a peroxyester compound (Perbutyl O, NOF Corporation) at 90°C and stirring for 3 hours at 90°C. The reaction solution was evaporated under reduced pressure and filtered to yield 320 g of organopolysiloxane (v) as a colorless, transparent liquid. The resulting organopolysiloxane (v) had a weight-average molecular weight of 1300, a mercapto equivalent of 1300 g / mol, and was represented by the following average compositional formula: (-C3H6-SH) 0.25 (-C3H6-S-C2H4-Si(OC2H5)3) 0.75(-OC2H5) 1.50 SiO 0.75 (v)

[0049] [Example 1-1] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 256 g (1 mole of mercapto groups) of the organopolysiloxane (ii) obtained in Synthesis Example 1-2 and 127 g (0.67 moles) of vinyltriethoxysilane (KBE-1003, Shin-Etsu Chemical Co., Ltd.), followed by the addition of 0.1 g of a peroxyester compound (Perbutyl O, NOF Corporation) at 90°C and stirring for 3 hours at 90°C. The reaction solution was evaporated under reduced pressure and filtered to yield 380 g of organopolysiloxane (vi) as a colorless, transparent liquid. The resulting organopolysiloxane (vi) had a weight-average molecular weight of 1150, a mercapto equivalent of 1150 g / mol, and was represented by the following average compositional formula: (-C3H6-SH) 0.25 (-C3H6-S-C2H4-Si(OC2H5)3) 0.50 (-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (vi)

[0050] [Example 1-2] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 256 g (1 mole of mercapto groups) of the organopolysiloxane (ii) obtained in Synthesis Example 1-2 and 142 g (0.75 moles) of vinyltriethoxysilane (KBE-1003, Shin-Etsu Chemical Co., Ltd.), followed by the addition of 0.1 g of a peroxyester compound (Perbutyl O, NOF Corporation) at 90°C and stirring for 3 hours at 90°C. The reaction solution was evaporated under reduced pressure and filtered to yield 395 g of organopolysiloxane (vii) as a colorless, transparent liquid. The resulting organopolysiloxane (vii) had a weight-average molecular weight of 1200, a mercapto equivalent of 1600 g / mol, and was represented by the following average compositional formula: (-C3H6SH) 0.19 (-C3H6S-C2H4-Si(OC2H5)3) 0.56(-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (vii)

[0051] [2] Preparation of rubber composition [Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-2] The SBR and BR shown in Table 1 were mixed for 30 seconds using a 4 L internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.). Next, the oil components, carbon black, silica, sulfide silane, organopolysiloxanes obtained in Synthesis Examples, Examples, and Comparative Synthesis Examples, stearic acid, antioxidants, and wax listed in Table 1 were added, the internal temperature was raised to 150°C, and the mixture was held at 150°C for 2 minutes before being discharged. It was then stretched using rolls. The resulting rubber was again kneaded using an internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.) until the internal temperature reached 140°C, discharged, and then stretched using rolls. To this was added zinc oxide, a vulcanization accelerator, and sulfur as shown in Table 1, and the mixture was kneaded to obtain a rubber composition.

[0052] SBR: SLR-4602 (manufactured by Trinseo) BR: BR-01 (JSR Corporation) Oil: AC-12 (Idemitsu Kosan Co., Ltd.) Carbon black: Seast 3 (manufactured by Tokai Carbon Co., Ltd.) Silica: Nipsil AQ (manufactured by Tosoh Silica Corporation) Sulfide silane: KBE-846 (Shin-Etsu Chemical Co., Ltd.) Stearic acid: Industrial stearic acid (Kao Corporation) Antioxidant: Nocrac 6C (Ouchi Shinko Chemical Industry Co., Ltd.) Wax: Ozoace 0355 (manufactured by Nippon Seiro Co., Ltd.) Zinc oxide: Zinc oxide No. 3 (manufactured by Mitsui Mining & Smelting Co., Ltd.) Vulcanization accelerator (a): Noccela D (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization accelerator (b): Noccela DM-P (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization accelerator (c): Noccela CZ-G (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Sulfur: 5% oil-treated sulfur (Hosoi Chemical Industry Co., Ltd.)

[0053] The unvulcanized and vulcanized physical properties of the rubber compositions obtained in Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-2 were measured by the following methods. The results are also shown in Tables 1 and 2. The vulcanized physical properties were measured using vulcanized rubber sheets (thickness 2 mm) prepared by press molding (160°C, 10 to 40 minutes) the obtained rubber compositions.

[0054] [Unvulcanized physical properties] (1) Mooney viscosity According to JIS K 6300-1:2013, measurements were performed with 1 minute of preheating and 4 minutes of measurement at a temperature of 130°C, and the results were expressed as an index, with Comparative Example 2-1 being set at 100. A smaller index value indicates a lower Mooney viscosity and better processability. (2) Vulcanization characteristics (T90) The vulcanization rate at 160°C was measured using a rotorless rheometer, and the minimum torque ML and maximum torque MH were determined from the vulcanization curve, and T90 (the time (minutes) required to reach 90% of the maximum torque value) was calculated. The results were expressed as an index, with Comparative Example 2-1 set to 100. A smaller index value indicates a faster vulcanization rate and better productivity. [Vulcanization properties] (3)Hardness Durometer (type A) hardness was measured in accordance with JIS K 6253-3:2012, and expressed as an index with Comparative Example 2-1 being 100. A larger index value indicates higher and more excellent hardness. (4) Tensile properties JIS No. 3 dumbbell-shaped test pieces were punched out and subjected to a tensile test at a tensile speed of 500 mm / min in accordance with JIS K6251. 300 ) [MPa] was measured at 25° C. The results were expressed as an index, with Comparative Example 2-1 being set at 100. A larger index value indicates a higher modulus and more excellent tensile properties. (5) Dynamic viscoelasticity (strain dispersion) Using a viscoelasticity measuring device (Metrabib), the storage modulus E' (0.5%) at 0.5% strain and the storage modulus E' (3.0%) at 3.0% strain were measured at 25°C and 55Hz, and the value of [E' (0.5%) - E' (3.0%)] was calculated. The test specimen was a sheet with a thickness of 0.2 cm and a width of 0.5 cm, with a clamp distance of 2 cm and an initial load of 1 N. The value of [E'(0.5%)-E'(3.0%)] is expressed as an index with Comparative Example 2-1 being 100, and the smaller the index value, the better the dispersibility of silica. (6) Dynamic viscoelasticity (temperature dispersion) Measurements were made using a viscoelasticity measuring device (Metrabib) under conditions of a tensile dynamic strain of 1% and a frequency of 55 Hz. The test specimen was a sheet of 0.2 cm thick and 0.5 cm wide, with a clamp distance of 2 cm and an initial load of 1 N. The values ​​of tan δ(0°C) and tan δ(60°C) are expressed as indexes, with Comparative Example 2-1 being 100. A larger index value for the tan δ(0°C) value indicates better wet grip performance. A smaller index value for the tan δ(60°C) value indicates better rolling resistance.

[0055] [Table 1]

[0056] As shown in Table 1, the rubber compositions of Examples 2-1 to 2-5 have excellent vulcanization characteristics, and are good in tensile properties, silica dispersibility, wet grip properties, and rolling resistance after vulcanization, compared to the rubber composition of Comparative Example 2-1, which does not contain the organopolysiloxane of the present invention. On the other hand, the rubber composition of Comparative Example 2-2, which used a mercapto group-containing organopolysiloxane that did not have a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl group-containing organic group, exhibited significantly reduced vulcanization characteristics, and was found to have poor tensile properties and rolling resistance after vulcanization.

Claims

1. an organopolysiloxane having a mercapto group-containing organic group and a trialkoxysilyl group-containing organic group, a dialkoxymethylsilyl group-containing organic group, or both; The organopolysiloxane is a rubber composition represented by the following average composition formula (1): (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1) [In the formula, A represents a mercapto group-containing organic group, B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl group-containing organic group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and a, b, c, and d represent numbers that satisfy 0<a<1, 0<b<1, 0<c<3, 0≦d<1, and 0<a+b+c+d<4.] The mercapto group-containing organic group is represented by the following formula (2): * -(CH 2 ) m -SH (2) (wherein m represents an integer of 1 to 10, * - indicates a bond.) The trialkoxysilyl group-containing organic group or the dialkoxymethylsilyl group-containing organic group is represented by the following formula (3): * -(CH 2 ) m -S-(CH 2 ) n -Si(CH 3 ) 3-k (OR 1 ) k (3) (wherein m represents an integer of 1 to 10, n represents an integer of 1 to 10, k represents 2 or 3, R 1 each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; * - indicates a bond.) and the hydrolyzable group is represented by the following formula (4): * -OR 1 (4) (In the formula, R 1 has the same meaning as above, * - indicates a bond.) It is expressed as follows.]

2. 2. The rubber composition according to claim 1, wherein d is a number that satisfies the condition 0<d<1.

3. An organopolysiloxane represented by the following average composition formula (1'): (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1’) [In the formula, A represents a mercapto group-containing organic group, B represents a trialkoxysilyl group-containing organic group or a dialkoxymethylsilyl group-containing organic group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and a, b, c, and d represent numbers that satisfy 0<a<1, 0<b<1, 0<c<3, 0<d<1, and 0<a+b+c+d<4.] The mercapto group-containing organic group is represented by the following formula (2): * -(CH 2 ) m -SH (2) (wherein m represents an integer of 1 to 10, * - indicates a bond.) The trialkoxysilyl group-containing organic group or the dialkoxymethylsilyl group-containing organic group is represented by the following formula (3): * -(CH 2 ) m -S-(CH 2 ) n -Si(CH 3 ) 3-k (OR 1 ) k (3) (wherein m represents an integer of 1 to 10, n represents an integer of 1 to 10, k represents 2 or 3, R 1 each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; * - indicates a bond.) and the hydrolyzable group is represented by the following formula (4): * -OR 1 (4) (In the formula, R 1 has the same meaning as above, * - indicates a bond.) It is expressed as follows.]

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