Rubber composition and organopolysiloxane

Abstract

For example, the rubber composition containing an organopolysiloxane represented by the following average compositional formula (1) and having a thiol group-containing organic group and one or both of a trialkoxysilyl group-containing organic group and a dialkoxymethylsilyl group-containing organic group, and the tensile property after vulcanization. The tire has excellent wet grip performance and low rolling resistance, and a desired low fuel consumption tire can be achieved. (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 an alkyl group having 1-12 carbon atoms, a haloalkyl group having 1-10 carbon atoms or an aryl group having 6-12 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. )

Description

Technical Field

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

[0002] Tires composed of a silica-filled rubber composition have excellent performance in automotive applications, particularly excellent abrasion resistance, rolling resistance, and wet grip. The improvement of these performances is closely related to the improvement of the low fuel consumption of tires, and thus, has been actively studied recently.

[0003] For the improvement of low fuel consumption, it is necessary to increase the silica filling rate of the rubber composition. For a silica-filled rubber composition, although the rolling resistance of the tire is reduced and the wet grip is improved, the unvulcanized viscosity is high, and multi-stage mixing etc. are required, which causes problems in workability. Therefore, for a rubber composition simply compounded with an inorganic filler such as silica, the dispersion of the filler is insufficient, and problems such as a significant reduction in breaking strength and abrasion resistance occur.

[0004] Therefore, in order to improve the dispersion of the inorganic filler in the rubber and to chemically bond the inorganic filler to the rubber matrix, a sulfur-containing organosilicon compound is required.

[0005] As the sulfur-containing organosilicon compound, a compound containing an alkoxysilyl group and a polysulfide silyl group in the molecule is known, and for example, bis-triethoxysilylpropyl tetrasulfide, bis-triethoxysilylpropyl disulfide, etc. are effective (see Patent Documents 1 to 4).

[0006] In addition, in addition to the above-mentioned organosilicon compounds having a polysulfide group, a thioester type organosilicon compound containing a blocked mercapto group, which is advantageous for the dispersion of silica, and the application of a sulfur-containing organosilicon compound of an ester exchange type in which an amino alcohol compound is used in a hydrolyzable silyl moiety that is advantageous for the affinity with silica due to hydrogen bond formation are also known (see Patent Documents 5 to 9).

[0007] However, even when using the sulfur-containing organosilicon compounds disclosed in the above-mentioned patent documents, a tire rubber composition that achieves the desired low fuel consumption has not been obtained. In addition, these sulfur-containing organosilicon compounds are more costly than sulfur ether type compounds, and the manufacturing method is complicated, and thus, there are problems in productivity etc., and various problems remain.

[0008] In addition, Patent Document 10 discloses a tire rubber composition using a polysiloxane having a mercapto group and a long-chain alkyl group. For a tire obtained from this composition, although the rolling resistance and wet grip are improved, there is a problem that the vulcanization characteristics are significantly deteriorated.

[0009] Prior art documents

[0010] Patent documents

[0011] Patent document 1: Japanese Patent Application Laid-Open No. 2004-525230

[0012] Patent document 2: Japanese Patent Application Laid-Open No. 2004-18511

[0013] Patent document 3: Japanese Patent Application Laid-Open No. 2002-145890

[0014] Patent document 4: U.S. Patent No. 6229036 Specification

[0015] Patent document 5: Japanese Patent Application Laid-Open No. 2005-8639

[0016] Patent document 6: Japanese Patent Application Laid-Open No. 2008-150546

[0017] Patent document 7: Japanese Patent Application Laid-Open No. 2010-132604

[0018] Patent document 8: Japanese Patent No. 4571125 Gazette

[0019] Patent document 9: U.S. Patent No. 6414061 Specification

[0020] Patent document 10: Japanese Patent No. 5339008 Gazette Summary of the invention

[0021] Problems to be solved by the invention

[0022] In view of the above actual situation, the present invention has been completed, and the object is to provide a rubber composition having excellent vulcanization characteristics, tensile characteristics, wet grip and low rolling resistance after vulcanization, and capable of realizing a desired low fuel consumption tire, and an organopolysiloxane that forms the above characteristics by being added to the rubber composition.

[0023] Means for solving the problems

[0024] The inventors of the present invention have conducted in-depth research to achieve the above object, and as a result, it has been found that a rubber composition containing an organopolysiloxane having an organic group containing a mercapto group and an organic group containing a trialkoxysilyl group or a dialkoxymethylsilyl group can improve vulcanization characteristics, tensile characteristics, wet grip and rolling resistance after vulcanization. At the same time, it has been found that a tire composed of the rubber composition can achieve low fuel consumption tire characteristics, and the present invention has been completed.

[0025] That is, the present invention provides:

[0026] 1. A rubber composition comprising an organopolysiloxane having an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, or both, and an organic group containing a mercapto group;

[0027] 2. The rubber composition according to 1, wherein the organopolysiloxane is represented by the following average compositional formula (1):

[0028] (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1)

[0029] (In the formula, A represents an organic group containing a mercapto group, B represents an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl 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.)

[0030] 3. The rubber composition according to 2, wherein the organic group containing a mercapto group is represented by the following formula (2),

[0031] *-(CH2) m -SH(2)

[0032] (In the formula, m represents an integer of 1 to 10, and *- represents a bonding end.)

[0033] The organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group is represented by the following formula (3),

[0034] *-(CH2) m -S-(CH2) n -Si(CH3) 3-k (OR 1 ) k (3)

[0035] (In the formula, m represents an integer of 1 to 10, n represents an integer of 1 to 10, k represents 2 or 3, and each R 1 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, and *- represents a bonding end.)

[0036] The hydrolyzable group is represented by the following formula (4),

[0037] *-OR1 (4)

[0038] (In the formula, R 1 represents the same meaning as described above, and *- represents a bonding end.)

[0039] 4. The rubber composition according to 2 or 3, wherein d is a number satisfying 0 < d < 1;

[0040] 5. An organopolysiloxane represented by the following average compositional formula (1’),

[0041] (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1’)

[0042] (In the formula, A represents an organic group containing a mercapto group, B represents an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl 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.)

[0043] Effects of the Invention

[0044] The vulcanization characteristics, tensile characteristics after vulcanization, wet grip, and low rolling resistance of the rubber composition of the present invention are excellent, and a tire formed using the rubber composition can achieve low fuel consumption tire characteristics. Detailed Description of the Invention

[0045] The present invention will be specifically described below.

[0046] [1] Organopolysiloxane

[0047] The organopolysiloxane compounded in the rubber composition of the present invention has one or both of an organic group containing a trialkoxysilyl group and an organic group containing a dialkoxymethylsilyl group and an organic group containing a mercapto group. Specifically, an organopolysiloxane represented by the following average compositional formula (1) is preferably used.

[0048] (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1)

[0049] In formula (1), A represents an organic group containing a mercapto group, B represents an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl 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 aspects of the dispersibility of silica and the physical properties of the rubber, a, b, c, and d are more preferably numbers satisfying 0.05 ≤ a ≤ 0.80, 0.10 ≤ b ≤ 0.9, 1 ≤ c ≤ 2.5, and 0 < d ≤ 0.6, and further preferably numbers satisfying 0.1 ≤ a ≤ 0.7, 0.2 ≤ b ≤ 0.8, 1 ≤ c ≤ 2.5, and 0.05 ≤ d ≤ 0.5.

[0050] Furthermore, a, b, c, and d mean the average molar numbers of the respective organic groups relative to 1 mole of silicon atoms.

[0051] More specifically, it is more preferable that the organic group containing a mercapto group in formula (1) is represented by the following formula (2)

[0052] *-(CH2) m -SH (2)

[0053] (In the formula, m represents an integer of 1 to 10, and *- represents a bonding end.)

[0054] It is represented that the organic group containing a trialkoxysilyl group or the organic group containing a dialkoxymethylsilyl group is represented by the following formula (3)

[0055] *-(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, and each R 1 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, and *- represents a bonding end.) It is represented that the above hydrolyzable group is represented by the following formula (4)

[0056] *-OR 1 (4)

[0057] (In the formula, R 1 represents the same meaning as above, and *- represents a bonding end.)

[0058] represents an organopolysiloxane.

[0059] In the above formulas (3) and (4), as R 1 Specific examples of the alkyl group having 1 to 20 carbon atoms as R include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, octadecyl, etc. Specific examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, naphthyl, etc. Specific examples of the aralkyl group having 7 to 10 carbon atoms include benzyl, etc. Specific examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, propenyl, pentenyl, etc.

[0060] In the above formula (1), specific examples of the alkyl group having 1 to 12 carbon atoms as D include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, etc. 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, 8-bromooctyl, etc. Specific examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, styryl, naphthyl, biphenyl, etc. Among them, from the viewpoints of availability of raw materials and physical properties of the rubber, n-octyl is preferred. In addition, when the unit containing D is contained in the organopolysiloxane, the dispersibility of silica is improved and the physical properties of the rubber are improved.

[0061] Specific examples of the organic group containing a mercapto group represented by the above formula (2) include groups represented by the following, etc.

[0062] *-CH2SH

[0063] *-C2H4SH

[0064] *-C3H6SH

[0065] *-C4H8SH

[0066] *-C5H 10 SH

[0067] *-C6H 12 SH

[0068] *-C7H 14 SH

[0069] *-C8H 16 SH

[0070] *-C9H 18 SH

[0071] *-C 10 H 20 SH

[0072] (In the formula, *- represents a bonding end. The same applies hereinafter.)

[0073] As specific examples of the trialkoxysilyl group-containing organic group or dimethoxymethylsilyl group-containing organic group represented by the above formula (3), groups represented by the following can be cited, etc.

[0074] *-C3H6-S-C2H4-Si(OCH3)3

[0075] *-C3H6-S-C2H4-SiCH3(OCH3)2

[0076] *-C3H6-S-C2H4-Si(OC2H5)3

[0077] *-C3H6-S-C2H4-SiCH3(OC2H5)2

[0078] *-C3H6-S-C6H 12 -Si(OCH3)3

[0079] *-C3H6-S-C6H 12 -SiCH3(OCH3)2

[0080] *-C3H6-S-C6H 12 -Si(OC2H5)3

[0081] *-C3H6-S-C6H 12 -SiCH3(OC2H5)2

[0082] *-C3H6-S-C8H 16 -Si(OCH3)3

[0083] *-C3H6-S-C8H 16 -SiCH3(OCH3)2

[0084] *-C3H6-S-C8H 16 -Si(OC2H5)3

[0085] *-C3H6-S-C8H 16 -SiCH3(OC2H5)2

[0086] *-CH2-S-C2H4-Si(OCH3)3

[0087] *-CH2-S-C2H4-SiCH3(OCH3)2

[0088] *-CH2-S-C2H4-Si(OC2H5)3

[0089] *-CH2-S-C2H4-SiCH3(OC2H5)2

[0090] *-CH2-S-C6H 12 -Si(OCH3)3

[0091] *-CH2-S-C6H 12 -SiCH3(OCH3)2

[0092] *-CH2-S-C6H 12 -Si(OC2H5)3

[0093] *-CH2-S-C6H 12 -SiCH3(OC2H5)2

[0094] *-CH2-S-C8H 16 -Si(OCH3)3

[0095] *-CH2-S-C8H 16 -SiCH3(OCH3)2

[0096] *-CH2-S-C8H 16 -Si(OC2H5)3

[0097] *-CH2-S-C8H 16 -SiCH3(OC2H5)2

[0098] Specific examples of the hydrolyzable group represented by the above formula (4) include groups represented by the following, etc.

[0099] *-OCH3

[0100] *-OC2H5

[0101] *-OC3H7

[0102] *-OC4H9

[0103] *-OC5H 11

[0104] The above organopolysiloxane can be produced by reacting a hydrolysis condensate 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 condensate 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).

[0105] [Chemical formula 1]

[0106]

[0107] (In the formula, R 1and m have the same meanings as described above, y represents an integer from 1 to 3, and Me represents methyl.)

[0108] [Chemical Formula 2]

[0109]

[0110] (In the formula, R 1 has the same meaning as described above, k represents an integer from 0 to 8, z is 2 or 3, and Me represents methyl.)

[0111] (R 1 O) z -Si-R 3 4-z (6)

[0112] (In the formula, R 1 has the same meaning as described above, R 3 represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and z represents an integer from 1 to 4.)

[0113] In the above formula (6), as specific examples of the alkyl group having 1 to 12 carbon atoms represented by R 3 , methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-decyl, etc. can be cited. As specific examples of the halogenated alkyl group having 1 to 10 carbon atoms, 1-chloromethyl, 3-chloropropyl, 6-chlorohexyl, 8-chlorooctyl, 1-bromomethyl, 3-bromopropyl, 6-bromohexyl, 8-bromooctyl, etc. can be cited. As specific examples of the aryl group having 6 to 12 carbon atoms, phenyl, tolyl, styryl, naphthyl, biphenyl, etc. can be cited.)

[0114] As specific examples of the organosilicon compound represented by the above formula (5), α-mercaptomethyltrimethoxysilane, α-mercaptomethylmethyldimethoxysilane, α-mercaptomethyltriethoxysilane, α-mercaptomethylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, etc. can be cited.)

[0115] As specific examples of the organosilicon compound represented by the above formula (6), there can be cited alkyl-containing organosilicon compounds such as methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, ethyltrimethoxysilane, ethylmethyldimethoxysilane, ethyltriethoxysilane, ethylmethyldiethoxysilane, butyltrimethoxysilane, butylmethyldimethoxysilane, butyltriethoxysilane, butylmethyldiethoxysilane, hexyltrimethoxysilane, hexylmethyldimethoxysilane, hexyltriethoxysilane, hexylmethyldiethoxysilane, octyltrimethoxysilane, octylmethyldimethoxysilane, octyltriethoxysilane, octylmethyldiethoxysilane, decyltrimethoxysilane, decylmethyldimethoxysilane, decyltriethoxysilane, decylmethyldiethoxysilane; aryl-containing organosilicon compounds such as phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane; haloalkyl-containing organosilicon compounds such as 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; tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane.

[0116] As specific examples of the alkenyl-containing organosilicon compound represented by the above formula (7), vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, allyltrimethoxysilane, allylmethyldimethoxysilane, allyltriethoxysilane, allylmethyldiethoxysilane, hexenyltrimethoxysilane, hexenylmethyldimethoxysilane, hexenyltriethoxysilane, hexenylmethyldiethoxysilane, octenyltrimethoxysilane, octenylmethyldimethoxysilane, octenyltriethoxysilane, octenylmethyldiethoxysilane, etc. can be cited.

[0117] The hydrolysis condensate of the mercapto-containing organosilicon compound represented by the above formula (5), or the co-hydrolysis condensate of the mercapto-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.

[0118] As the hydrolysis-condensation catalyst, various catalysts known in the past can be applied. As specific examples thereof, 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; organometallic salts such as tetrabutyl titanate and dibutyltin dilaurate; F-containing compounds such as KF and NH4F, etc. These can be used alone or in combination of multiple kinds.

[0119] Regarding the usage amount of the catalyst, a range of 0.0001 to 1 mol% is preferably relative to all reaction components.

[0120] The amount of water used in the hydrolysis and condensation reaction can be adjusted according to the required degree of polymerization. Generally, relative to 1 mol of the whole hydrolyzable silyl group, 0.5 to 0.99 mol is preferred, and 0.66 to 0.90 mol is more preferred.

[0121] Furthermore, in the hydrolysis-condensation reaction, a solvent can be used as needed.

[0122] As the solvents that can be used, alcohols such as methanol, ethanol, isopropyl alcohol, and tert-butanol; ketones such as acetone and methyl isobutyl ketone; ethers such as dibutyl ether; esters such as ethyl acetate; aromatic compounds such as toluene, etc. can be cited. Among these, alcohols such as methanol and ethanol are preferred.

[0123] The reaction of the hydrolysis condensate of the mercapto-containing organosilicon compound represented by the above formula (5), or the co-hydrolysis condensate of the mercapto-containing organosilicon compound represented by the above formula (5) and the organosilicon compound represented by the above formula (6) with the alkenyl-containing organosilicon compound represented by the above formula (7) can use the technology of the known ene-thiol reaction.

[0124] In the ene-thiol reaction, catalysts such as organic peroxides and azo compounds can be used as needed.

[0125] Specific examples of the organic peroxide include benzoyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, dicumyl peroxide, etc.

[0126] Specific examples of the azo compound include 2,2'-azobispropane, 2,2'-dichloro-2,2'-azobispropane, 1,1'-azobis(methylethyl) diacetate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile (AIBN), methyl 2,2'-azobis(2-methylpropionate), 2,2'-dichloro-2,2'-azobutane, 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 3,5-dihydroxymethylphenylazo-2-methylmalononitrile, 2,2'-azobis(2-methylvaleronitrile), dimethyl 4,4'-azobis(4-cyanovalerate), 2,2'-azobis(2,4-dimethylvaleronitrile), etc.

[0127] The usage amount of the catalyst is preferably 0.00001 to 10 parts by mass relative to 100 parts by mass of the total amount of the hydrolysis condensate of the mercapto-containing organosilicon compound represented by the above formula (5), or the co-hydrolysis condensate of the mercapto-containing organosilicon compound represented by the above formula (5) and the organosilicon compound represented by the above formula (6) and the alkenyl-containing organosilicon compound represented by the above formula (7).

[0128] In the ene-thiol reaction, a solvent can be used as needed.

[0129] Examples of the solvent that can be used include alcohols such as methanol, ethanol, isopropanol, and tert-butanol; ketones such as acetone and methyl isobutyl ketone; ethers such as dibutyl ether; esters such as ethyl acetate; aromatic compounds such as toluene; hydrocarbons such as hexane and decane, etc.

[0130] From the aspect of suppressing the volatilization of the vinyl group-containing organosilicon compound represented by the above formula (7), the reaction temperature of the ene-thiol reaction is preferably 0 to 200 °C, more preferably 50 to 150 °C.

[0131] [2] Rubber composition

[0132] The rubber composition of the present invention contains the above-mentioned organopolysiloxane (A), and may further contain a diene rubber (B) and a filler (C).

[0133] Regarding the compounding amount of the above-mentioned organopolysiloxane (A), considering the balance of the physical properties of the resulting rubber, the degree of the effects exerted, and economy, etc., it is preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the filler (C) described later.

[0134] As the diene rubber (B), any rubber that has been conventionally used in various rubber compositions can be used. Specific examples thereof include natural rubber (NR); various isoprene rubbers (IR), various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubbers (NBR), etc. These diene rubbers can be used alone, or two or more of them can be used in combination. In addition, other than diene rubbers, non-diene rubbers such as butyl rubber (IIR) and ethylene-propylene copolymer rubbers (EPR, EPDM) can be used in combination.

[0135] 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 rubber composition containing silica.

[0136] In this case, regarding the compounding amount of the filler (C), considering the balance of the physical properties of the resulting rubber, the degree of the effects exerted, and economy, etc., it is preferably 5 to 200 parts by mass, more preferably 30 to 120 parts by mass, relative to 100 parts by mass of the diene rubber.

[0137] Furthermore, in the rubber composition of the present invention, in addition to the components (A) to (C) described above, various additives that are usually compounded in tires, such as carbon black, vulcanizing agent, crosslinking agent, vulcanization accelerator, crosslinking accelerator, various oils, anti-aging agent, plasticizer, etc., can be compounded. As long as the compounding amounts of these additives do not violate the object of the present invention, they can be set to the conventionally usual compounding amounts.

[0138] The rubber composition of the present invention can be obtained by kneading the above-mentioned components (A) to (C) and other components optionally used according to a conventional method.

[0139] [3] Rubber product (tire)

[0140] The rubber composition of the present invention can be used in the manufacture of rubber products such as tires, etc., which are vulcanized or crosslinked. In particular, in the case of manufacturing a tire, it is preferred to use the rubber composition of the present invention for the tread.

[0141] Since the rolling resistance performance and wet grip performance of the tire obtained by using the rubber composition of the present invention are greatly improved, the desired low fuel consumption can be achieved.

[0142] Furthermore, the structure of the tire can be set to a conventionally well-known structure, and its manufacturing method can also adopt a conventionally well-known method. Additionally, in the case of a pneumatic tire, as the gas filled in the tire, in addition to ordinary air and air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can also be used.

[0143] Examples

[0144] Synthesis examples, examples, and comparative examples are shown below to explain the present invention in more detail, but the present invention is not limited to these examples. Furthermore, in the following examples, the weight-average molecular weight represents the polystyrene conversion value measured by gel permeation chromatography (GPC).

[0145] [1] Synthesis of organopolysiloxane

[0146] [Synthesis Example 1-1]

[0147] In a 2 L detachable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, 953 g (4.0 moles) of 3-mercaptopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-803) and 100 g of ethanol were charged, and then 54 g (3.0 moles of water) of 0.5 N hydrochloric acid water was dropped at 25°C. Then, it was stirred at 80°C for 10 hours, and then cooled to 25°C. 3.0 g of propylene oxide was dropped, and it was stirred at 25°C for 1 hour. The reaction solution was distilled off under reduced pressure and filtered to obtain 730 g of a colorless transparent liquid organopolysiloxane (i). The weight-average molecular weight of the obtained organopolysiloxane (i) was 730, and the mercapto equivalent was 183 g / mol, which was represented by the following average composition formula.

[0148] (-C3H6-SH) 1.00 (-OC2H5) 1.50 SiO 0.75 (i)

[0149] [Synthesis Example 1-2]

[0150] In a 2 L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 715 g (3.0 moles) of 3-mercaptopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-803), 277 g (1.0 mole) of octyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-3083), and 100 g of ethanol were charged. Then, 54 g (3.0 moles of water) of 0.5 N hydrochloric acid water was dropped in at 25°C. Then, it was stirred at 80°C for 10 hours, and then cooled to 25°C. 3.0 g of propylene oxide was dropped in, and it was stirred at 25°C for 1 hour. The reaction solution was distilled off under reduced pressure and filtered to obtain 770 g of a colorless transparent liquid organic polysiloxane (ii). The obtained organic polysiloxane (ii) had a weight average molecular weight of 770 and a mercapto equivalent of 256 g / mol, and was represented by the following average composition formula.

[0151] (-C3H6-SH) 0.75 (-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (ii)

[0152] [Comparative Synthesis Example 1-1]

[0153] In a 2 L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 238 g (1.0 mole) of 3-mercaptopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-803), 831 g (3.0 moles) of octyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-3083), and 100 g of ethanol were charged. Then, 54 g (3.0 moles of water) of 0.5 N hydrochloric acid water was dropped in at 25°C. Then, it was stirred at 80°C for 10 hours, and then cooled to 25°C. 3.0 g of propylene oxide was dropped in, and it was stirred at 25°C for 1 hour. The reaction solution was distilled off under reduced pressure and filtered to obtain 840 g of a colorless transparent liquid organic polysiloxane (iii). The obtained organic polysiloxane (iii) had a weight average molecular weight of 850 and a mercapto equivalent of 845 g / mol, and was represented by the following average composition formula.

[0154] (-C3H6-SH) 0.25 (-C8H 17 ) 0.75 (-OC2H5) 1.50 SiO 0.75 (iii)

[0155] [Synthesis Example 1-4]

[0156] In a 1-L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 183 g (1 mol in terms of mercapto group) of the organopolysiloxane (i) obtained in Synthesis Example 1-1 and 95 g (0.5 mol) of vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-1003) were charged. Then, 0.1 g of a peroxyester compound (Perbutyl O manufactured by NOF Corporation) was added at 90°C, and the mixture was stirred at 90°C for 3 hours. The reaction solution was distilled off under reduced pressure and filtered to obtain 275 g of a colorless and transparent liquid organopolysiloxane (iv). The obtained organopolysiloxane (iv) had a weight-average molecular weight of 1100 and a mercapto equivalent of 555 g / mol, and was represented by the following average compositional formula.

[0157] (-C3H6-SH) 0.50 (-C3H6-S-C2H4-Si(OC2H5)3) 0.50 (-OC2H5) 1.50 SiO 0.75 (iv)

[0158] [Synthesis Example 1-5]

[0159] In a 1-L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 183 g (1 mol in terms of mercapto group) of the organopolysiloxane (i) obtained in Synthesis Example 1-1 and 143 g (0.75 mol) of vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-1003) were charged. Then, 0.1 g of a peroxyester compound (Perbutyl O manufactured by NOF Corporation) was added at 90°C, and the mixture was stirred at 90°C for 3 hours. The reaction solution was distilled off under reduced pressure and filtered to obtain 320 g of a colorless and transparent liquid organopolysiloxane (v). The obtained organopolysiloxane (v) had a weight-average molecular weight of 1300 and a mercapto equivalent of 1300 g / mol, and was represented by the following average compositional formula.

[0160] (-C3H6-SH) 0.25 (-C3H6-S-C2H4-Si(OC2H5)3) 0.75 (-OC2H5) 1.50 SiO 0.75 (v)

[0161] [Example 1-1]

[0162] In a 1 L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 256 g (1 mole in terms of mercapto group) of the organopolysiloxane (ii) obtained in Synthesis Example 1-2 and 127 g (0.67 mole) of vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-1003) were charged. Then, 0.1 g of a peroxyester compound (Perbutyl O manufactured by NOF Corporation) was added at 90°C, and the mixture was stirred at 90°C for 3 hours. The reaction solution was distilled under reduced pressure and filtered to obtain 380 g of a colorless transparent liquid of organopolysiloxane (vi). The weight-average molecular weight of the obtained organopolysiloxane (vi) was 1150, and the mercapto equivalent was 1150 g / mole, which was represented by the following average composition formula.

[0163] (-C3H6-SH) 0.25 (-C3H6-S-C2H4-Si(OC2H5)3) 0.50 (-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (vi)

[0164] [Example 1-2]

[0165] In a 1 L detachable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 256 g (1 mole in terms of mercapto group) of the organopolysiloxane (ii) obtained in Synthesis Example 1-2 and 142 g (0.75 mole) of vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-1003) were charged. Then, 0.1 g of a peroxyester compound (Perbutyl O manufactured by NOF Corporation) was added at 90°C, and the mixture was stirred at 90°C for 3 hours. The reaction solution was distilled under reduced pressure and filtered to obtain 395 g of a colorless transparent liquid of organopolysiloxane (vii). The weight-average molecular weight of the obtained organopolysiloxane (vii) was 1200, and the mercapto equivalent was 1600 g / mole, which was represented by the following average composition formula.

[0166] (-C3H6SH) 0.19 (-C3H6S-C2H4-Si(OC2H5)3) 0.56 (-OC2H5) 1.50 (-C8H 17 ) 0.25 SiO 0.75 (vii)

[0167] [2] Preparation of Rubber Composition

[0168] [Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-2]

[0169] Using a 4L internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.), the SBR and BR listed in Table 1 were kneaded for 30 seconds.

[0170] Next, the oil components, carbon black, silica, thioether silane, the organopolysiloxanes obtained in the synthesis examples, examples, and comparative synthesis examples, stearic acid, antioxidant, and wax listed in Table 1 were added, and the internal temperature was raised to 150 °C. After maintaining at 150 °C for 2 minutes, it was discharged. Then, it was stretched using a roll. The resulting rubber was kneaded again using an internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.) until the internal temperature reached 140 °C. After discharging, it was stretched using a roll.

[0171] Zinc oxide, vulcanization accelerator, and sulfur listed in Table 1 were added thereto and kneaded to obtain a rubber composition.

[0172] SBR: SLR-4602 (manufactured by Trinseo)

[0173] BR: BR-01 (manufactured by JSR Corporation)

[0174] Oil: AC-12 (manufactured by Idemitsu Kosan Co., Ltd.)

[0175] Carbon black: Seast 3 (manufactured by Tokai Carbon Co., Ltd.)

[0176] Silica: Nipsil AQ (manufactured by Tosoh Silica Corporation)

[0177] Thioether silane: KBE-846 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0178] Stearic acid: Industrial grade stearic acid (manufactured by Kao Corporation)

[0179] Antioxidant: Nocrac 6C (manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.)

[0180] Wax: Ozoace-0355 (manufactured by Nippon Seiro Co., Ltd.)

[0181] Zinc oxide: Zinc oxide No. 3 (manufactured by Mitsui Mining & Smelting Co., Ltd.)

[0182] Vulcanization accelerator (a): Nocceler D (manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.)

[0183] Vulcanization accelerator (b): Nocceler DM-P (manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.)

[0184] Vulcanization accelerator (c): Nocceler CZ-G (manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.)

[0185] Sulfur: 5% oil-treated sulfur (manufactured by Hosoi Chemical Industry Co., Ltd.)

[0186] For the rubber compositions obtained in the above Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-2, the unvulcanized physical properties and vulcanized physical properties were measured by the following methods. The results are shown together in Tables 1 and 2. Further, regarding the vulcanized physical properties, they were measured using a vulcanized rubber sheet (2 mm thick) produced by compression molding the obtained rubber composition (at 160 °C for 10 to 40 minutes).

[0187] [Unvulcanized Physical Properties]

[0188] (1) Mooney viscosity

[0189] In accordance with JIS K 6300-1:2013, it was measured at a preheating temperature of 1 minute, a measurement time of 4 minutes, and a temperature of 130 °C. Taking Comparative Example 2-1 as 100, the obtained results were expressed as an index. The smaller the index value, the lower the Mooney viscosity and the better the processability.

[0190] (2) Vulcanization characteristics (T90)

[0191] Using a rotorless rheometer, the vulcanization rate at 160 °C was measured. The minimum torque ML and the maximum torque MH were obtained from the vulcanization curve, and T90 (the arrival time (minutes) of the torque value reaching 90% of the maximum torque value) was calculated. Taking Comparative Example 2-1 as 100, the obtained results were expressed as an index. The smaller the index value, the faster the vulcanization rate and the better the productivity.

[0192] [Vulcanized Physical Properties]

[0193] (3) Hardness

[0194] In accordance with JIS K 6253-3:2012, the hardness of a durometer (Type A) was measured. Taking Comparative Example 2-1 as 100, the obtained results were expressed as an index. The larger the index value, the higher the hardness and the better the performance.

[0195] (4) Tensile properties

[0196] A test piece in the shape of a JIS No. 3 dumbbell was punched out, and a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251. The 300% modulus (M 300 ) [MPa] was measured at 25 °C. Taking Comparative Example 2-1 as 100, the obtained results were expressed as an index. The larger the index value, the higher the modulus and the better the tensile properties.

[0197] (5) Dynamic viscoelasticity (strain dispersion)

[0198] Using a viscoelasticity measuring device (manufactured by Metravib), the storage modulus E’(0.5%) at a strain of 0.5% and the storage modulus E’(3.0%) at a strain of 3.0% were measured under the conditions of a temperature of 25 °C and a frequency of 55 Hz, and the value of [E’(0.5%) - E’(3.0%)] was calculated. Furthermore, for the test piece, a sheet with a thickness of 0.2 cm and a width of 0.5 cm was used, the distance between the used jigs was set to 2 cm, and the initial load was set to 1 N.

[0199] Regarding the value of [E’(0.5%) - E’(3.0%)], Comparative Example 2-1 was set to 100 and expressed as an index. The smaller the index value, the better the dispersion of silica.

[0200] (6) Dynamic viscoelasticity (temperature dispersion)

[0201] Using a viscoelasticity measuring device (manufactured by Metravib), the measurement was carried out under the conditions of a dynamic strain of 1% in tension and a frequency of 55 Hz. Furthermore, for the test piece, a sheet with a thickness of 0.2 cm and a width of 0.5 cm was used, the distance between the used jigs was set to 2 cm, and the initial load was set to 1 N.

[0202] Regarding the values of tanδ(0 °C) and tanδ(60 °C), Comparative Example 2-1 was set to 100 and expressed as an index. Regarding the value of tanδ(0 °C), the larger the index value, the better the wet grip performance. Regarding the value of tanδ(60 °C), the smaller the index value, the better the rolling resistance.

[0203] [Table 1]

[0204]

[0205] As shown in Table 1, it can be seen that the rubber compositions of Examples 2-1 to 2-5 have excellent vulcanization characteristics, and good tensile characteristics, silica dispersion, wet grip performance, and rolling resistance after vulcanization compared with the rubber composition of Comparative Example 2-1 that does not contain the organopolysiloxane of the present invention.

[0206] On the other hand, it can be seen that the vulcanization characteristics of the rubber composition of Comparative Example 2-2 using a mercapto-containing organopolysiloxane that does not have an organo group containing trialkoxysilyl and an organo group containing dialkoxymethylsilyl are significantly reduced, and the tensile characteristics and rolling resistance after vulcanization are poor.

Claims

1. A rubber composition comprising an organopolysiloxane having an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, or both, and an organic group containing a mercapto group.

2. The rubber composition according to claim 1, wherein The organopolysiloxane is represented by the following average compositional formula (1): (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1) In the formula, A represents an organic group containing a mercapto group, B represents an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl 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 claim 2, wherein The organic group containing a mercapto group is represented by the following formula (2), *-(CH2) m -SH (2) In the formula, m represents an integer of 1 to 10, and *- represents a bonding end. The organic group containing a trialkoxysilyl group or the organic group containing a dialkoxymethylsilyl 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 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 2 to 10 carbon atoms, and *- represents a bonding end. The hydrolyzable group is represented by the following formula (4), *-OR 1 (4) In the formula, R 1 represents the same meaning as described above, and *- represents the bonding end.

4. The rubber composition according to claim 2 or 3, wherein The d is a number satisfying 0 < d < 1.

5. An organopolysiloxane represented by the following average compositional formula (1’), (A) a (B) b (C) c (D) d SiO (4-a-b-c-d) / 2 (1’) In the formula, A represents an organic group containing a mercapto group, B represents an organic group containing a trialkoxysilyl group or an organic group containing a dialkoxymethylsilyl group, C represents a hydrolyzable group, D represents an alkyl group having 1 to 12 carbon atoms, a halogenated alkyl 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.

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