JP2012012458A - Method of manufacturing vulcanized rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a vulcanized rubber composition improved in viscoelastic properties, which method can be carried out in a low energy.SOLUTION: The method for manufacturing a vulcanized rubber composition containing a rubber component, a filler, a metal salt of S-(3-aminopropyl)thiosulfuric acid, a sulfur component, and a vulcanization accelerator includes: a pre-kneading step A of kneading the rubber composition, the filler and the metal salt of S-(3-aminopropyl)thiosulfuric acid under the temperature-rise condition in which the temperature at the initiation is ≥40°C and ≤100°C and the temperature at the finish is ≥110°C and ≤155°C; a post-kneading step B of kneading the kneaded material A obtained in the pre-kneading step A, the sulfur component and the vulcanization accelerator; and a heat treatment step C of thermally treating the kneaded material B obtained in the post-kneading step B to obtain a vulcanized rubber.

Description

  The present invention relates to a method for producing a vulcanized rubber composition with improved productivity.

  Rubber compositions are used in various fields, and in particular as raw materials for automobile tires. In addition to rubber components such as natural rubber and synthetic rubber, various materials are blended as raw materials for tires to obtain rubber compositions. Examples thereof include fillers such as carbon black, sulfur components necessary for vulcanization, and vulcanization accelerators that accelerate vulcanization. In addition, various substances are blended in order to impart predetermined characteristics to the rubber component. For example, Patent Document 1 discloses a substance that promotes adhesion between rubber and metal. Specifically, it is disclosed that 6-aminohexylthiosulfuric acid S-ester is used as a rubber / metal adhesion promoter (Example 24 of Patent Document 1).

  By the way, a vulcanized rubber product obtained by heat-treating a rubber composition is mainly used as a tire raw material for automobiles and the like. For this reason, the vulcanized rubber composition is required to have excellent viscoelastic properties. Examples of the viscoelastic property include tan δ at 60 ° C., which is a measure of rolling resistance. When tan δ at 60 ° C. is small, fuel efficiency is improved, and thus viscoelastic properties are an important factor in designing a vulcanized rubber composition (page 124 of Non-Patent Document 1).

  Furthermore, environmental technology is required in recent product development. As part of this, it is also important to reduce energy in the production of vulcanized rubber compositions.

Japanese Patent Publication No. 5-15173 (released February 26, 1993)

Publisher: Takehiko Koshiro, Editor: Japan Rubber Association, Literature Name: Introduction to Rubber Technology, Publisher: Maruzen Co., Ltd., Publication Date: March 10, 2004, pages 123-124

  Although improvement of viscoelastic properties is important, in the production of vulcanized rubber compositions, the raw rubber components, fillers, sulfur components, vulcanized components, etc. affect the physical properties of the vulcanized rubber composition. It is not easy to improve viscoelastic properties. Furthermore, in addition to the above problems, there is a harsh situation where it is also required to achieve energy reduction in the production of vulcanized rubber compositions.

  The present invention has been made in view of the above-mentioned conventional problems, and its object is to provide a method for producing a vulcanized rubber composition that can be carried out at low energy and has improved viscoelastic properties. is there.

The method for producing a vulcanized rubber composition of the present invention contains a rubber component, a filler, a metal salt of S- (3-aminopropyl) thiosulfuric acid, a sulfur component, and a vulcanization accelerator in order to solve the above problems. A method for producing a vulcanized rubber composition,
Rubber components, fillers, S- (3-aminopropyl) under temperature rising conditions where the temperature at the start is 40 ° C. or more and 100 ° C. or less and the temperature at the end is 110 ° C. or more and 155 ° C. or less Pre-kneading step A for kneading a metal salt of thiosulfuric acid;
A post-kneading step B in which the kneaded product A obtained in the pre-kneading step A, the sulfur component and the vulcanization accelerator are kneaded;
A heat treatment step C for obtaining a vulcanized rubber by heat-treating the kneaded product B obtained in the post-kneading step B;
It is characterized by including.

  According to the above invention, in the pre-kneading step A, a metal salt of S- (3-aminopropyl) thiosulfuric acid is used for kneading, so that even at a low starting temperature and a ending temperature can be added. A vulcanized rubber can be obtained, and the production method can be carried out with low energy. Furthermore, the viscoelastic properties of the resulting vulcanized rubber composition can be improved.

  Moreover, in the manufacturing method of the vulcanized rubber composition of this invention, it is preferable that the temperature at the said start is 80 degreeC or more and 100 degrees C or less, and the temperature at the end is 135 degreeC or more and 155 degrees C or less.

  Thereby, the viscoelastic property of the obtained vulcanized rubber composition can be further improved by an easy procedure in which the temperature at the start and the temperature at the end are within the above ranges.

  In the method for producing a vulcanized rubber composition of the present invention, the weight of the metal salt of S- (3-aminopropyl) thiosulfuric acid relative to 100 parts by weight of the rubber component is 0.05 parts by weight or more and 2.5 parts by weight. The following is preferable.

  By being in the above-mentioned range, it is possible to preferably obtain an effect of further improving the viscoelastic properties of the obtained vulcanized rubber composition.

As described above, the method for producing a vulcanized rubber composition of the present invention includes a rubber component, a filler, a metal salt of S- (3-aminopropyl) thiosulfuric acid, a sulfur component and a vulcanization accelerator. A method for producing a rubber composition,
Rubber components, fillers, S- (3-aminopropyl) under temperature rising conditions where the temperature at the start is 40 ° C. or more and 100 ° C. or less and the temperature at the end is 110 ° C. or more and 155 ° C. or less Pre-kneading step A for kneading a metal salt of thiosulfuric acid;
A post-kneading step B in which the kneaded product A obtained in the pre-kneading step A, the sulfur component and the vulcanization accelerator are kneaded;
A heat treatment step C for obtaining a vulcanized rubber by heat-treating the kneaded product B obtained in the post-kneading step B;
It is a method including.

  Therefore, in the pre-kneading step A, by using a metal salt of S- (3-aminopropyl) thiosulfuric acid for kneading, a vulcanized rubber is obtained even at a low start temperature and end temperature. Therefore, the present manufacturing method can be carried out with low energy. Furthermore, the viscoelastic property of the obtained vulcanized rubber composition can be improved.

Hereinafter, a method for producing a vulcanized rubber composition according to the present invention (hereinafter abbreviated as “the production method of the present invention” as appropriate) will be described in detail. The production method of the present invention is a method for producing a vulcanized rubber composition containing a rubber component, a filler, a metal salt of S- (3-aminopropyl) thiosulfuric acid, a sulfur component and a vulcanization accelerator,
Rubber components, fillers, S- (3-aminopropyl) under temperature rising conditions where the temperature at the start is 40 ° C. or more and 100 ° C. or less and the temperature at the end is 110 ° C. or more and 155 ° C. or less Pre-kneading step A for kneading a metal salt of thiosulfuric acid;
A post-kneading step B in which the kneaded product A obtained in the pre-kneading step A, the sulfur component and the vulcanization accelerator are kneaded;
A heat treatment step C for obtaining a vulcanized rubber by heat-treating the kneaded product B obtained in the post-kneading step B;
It is a method including.

  First, each component used in the pre-kneading process A will be described.

[Rubber component]
Rubber components include natural rubber, epoxidized natural rubber, deproteinized natural rubber and other modified natural rubber, as well as styrene / butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), acrylonitrile. Examples include various synthetic rubbers such as butadiene copolymer rubber (NBR), isoprene / isobutylene copolymer rubber (IIR), ethylene / propylene-diene copolymer rubber (EPDM), and halogenated butyl rubber (HR). Among these, highly unsaturated rubbers such as natural rubber, styrene / butadiene copolymer rubber and polybutadiene rubber are preferably used. Particularly preferred is natural rubber. It is also effective to combine several rubber components such as a combination of natural rubber and styrene / butadiene copolymer rubber, a combination of natural rubber and polybutadiene rubber.

  Examples of natural rubber include natural rubber of grades such as RSS # 1, RSS # 3, TSR20, SIR20, SMR20 and the like.

  As the epoxidized natural rubber, those having a degree of epoxidation of 10 to 60 mol% are preferable, and examples thereof include ENR25 and ENR50 manufactured by Kumpoulan_Gusley. As the deproteinized natural rubber, a deproteinized natural rubber having a total nitrogen content of 0.3% by weight or less is preferable. Modified natural rubber containing a polar group obtained by reacting natural rubber in advance with 4-vinylpyridine, N, N-dialkylaminoethyl acrylate (for example, N, N-diethylaminoethyl acrylate), 2-hydroxy acrylate, etc. Is preferably used.

  Examples of the SBR include emulsion polymerization SBR and solution polymerization SBR described in pages 210 to 211 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. In particular, solution-polymerized SBR is preferably used as a rubber composition for a tread, and further, the molecular terminal is terminated by using 4,4′-bis- (dialkylamino) benzophenone such as “Nippol (registered trademark) NS116” manufactured by Nippon Zeon Co., Ltd. Modified solution polymerized SBR, solution polymerized SBR in which molecular ends are modified using tin halide compounds such as “SL574” manufactured by JSR, and silane-modified solution polymerized SBR such as “E10” and “E15” manufactured by Asahi Kasei Or a lactam compound, an amide compound, a urea compound, an N, N-dialkylacrylamide compound, an isocyanate compound, an imide compound, a silane compound having an alkoxy group (trialkoxysilane compound, etc.), or an aminosilane compound. Or a silane compound having a tin compound and an alkoxy group In addition, two or more of the above-described different compounds such as an alkylacrylamide compound and an alkoxy group-containing silane compound are used, and each of the molecular ends obtained by modifying the molecular ends is nitrogen, tin, or silicon, or Solution polymerization SBR having these plural elements is particularly preferably used. Oil-extended SBR in which oil such as post-polymerization process oil and aroma oil is added to emulsion polymerization SBR and solution polymerization SBR can be preferably used as a rubber composition for treads.

  Examples of BR include solution polymerization BR such as high cis BR having 90% or more of cis 1,4 bond and low cis BR having cis bond of around 35%, and low cis BR having a high vinyl content is preferably used. . Furthermore, tin-modified BR such as “Nipol (registered trademark) BR — 1250H” manufactured by Nippon Zeon, 4,4′-bis- (dialkylamino) benzophenone, tin halide compound, lactam compound, amide compound, urea compound, N, N -A dialkylacrylamide compound, an isocyanate compound, an imide compound, a silane compound having an alkoxy group (trialkoxysilane compound, etc.), an aminosilane compound alone, a silane compound having a tin compound and an alkoxy group, or an alkyl Two or more of the above-mentioned different compounds such as an acrylamide compound and an alkoxy group-containing silane compound are used, and each of the molecular ends obtained by modifying the molecular ends is nitrogen, tin, silicon, or a plurality thereof. Solution containing the elements of If BR is particularly preferably used. These BRs can be preferably used as a rubber composition for a tread or a rubber composition for a sidewall, and are usually used in a blend with SBR and / or natural rubber. In the rubber composition for treads, the blend ratio is preferably 60 to 100% by weight for SBR and / or natural rubber and 0 to 40% by weight for BR relative to the total rubber weight. In the rubber composition for sidewalls, The SBR and / or natural rubber is preferably 10 to 70% by weight and the BR is preferably 90 to 30% by weight based on the total rubber weight, and further the natural rubber is 40 to 60% by weight and BR 60 to 40% based on the total rubber weight. Weight percent blends are particularly preferred. In this case, a blend of modified SBR and non-modified SBR or a blend of modified BR and non-modified BR is also preferable.

〔filler〕
Examples of the filler include carbon black, silica, talc, clay, aluminum hydroxide, titanium oxide and the like that are usually used in the rubber field. Carbon black and silica are preferably used, and carbon black is particularly preferable. Preferably used. Examples of the carbon black include those described in page 494 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Among these, carbon blacks such as HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate SAF), FEF (Fast Extrusion Furnace), MAF, GPF (General Purpose Furnace), SRF (Semi-Reinforcing Furnace), etc. are preferable. . Tire tread rubber composition for CTAB (Cetyl Tri-methyl Ammonium Bromide ) surface area 40~250m ² / g, nitrogen adsorption specific surface area 20 to 200 m ² / g, carbon black having a particle diameter 10~50nm are preferably used, CTAB Carbon black having a surface area of 70 to 180 m ² / g is more preferable, and examples thereof include N110, N220, N234, N299, N326, N330, N330T, N339, N343, and N351 in the ASTM standard. A surface-treated carbon black in which 0.1 to 50% by weight of silica is attached to the surface of the carbon black is also preferable. Furthermore, it is also effective to combine several kinds of fillers such as the combined use of carbon black and silica, and it is preferable to use carbon black alone or both carbon black and silica in the rubber composition for a tire tread. In the rubber composition for carcass and sidewall, carbon black having a CTAB surface area of 20 to 60 m ² / g and a particle size of 40 to 100 nm is preferably used. Examples thereof include N330, N339, N343, N351, N550 in the ASTM standard. N568, N582, N630, N642, N660, N662, N754, N762, and the like.

  The amount of the filler used is not particularly limited, but is preferably in the range of 5 to 100 parts by weight per 100 parts by weight of the rubber component. Particularly preferred is a range of 30 to 80 parts by weight when only carbon black is used as a filler, and a range of 5 to 50 parts by weight when used in combination with silica in a tread member application.

Examples of the silica include silica having a CTAB surface area of 50 to 180 m ² / g and a nitrogen adsorption specific surface area of 50 to 300 m ² / g. “AQ”, “AQ-N” manufactured by Tosoh Silica Corporation, Degussa "Ultrasil (registered trademark) VN3", "Ultrasil (registered trademark) 360", "Ultrasil (registered trademark) 7000" manufactured by Rhodia, "Zeosil (registered trademark) 115GR", "Zeosil (registered trademark) 1115MP" manufactured by Rhodia , “Zeosil (registered trademark) 1205MP”, “Zeosil (registered trademark) Z85MP”, “Nippal (registered trademark) AQ” manufactured by Nippon Silica Co., Ltd., and the like are preferably used. Further, silica having a pH of 6 to 8, silica containing 0.2 to 1.5% by weight of sodium, true spherical silica having a roundness of 1 to 1.3, silicone oil such as dimethyl silicone oil, and ethoxysilyl group It is also preferable to use an organosilicon compound containing silane, silica surface-treated with an alcohol such as ethanol or polyethylene glycol, and silica having two or more different nitrogen adsorption specific surface areas.

  The amount of the filler used is not particularly limited, but silica is preferably used in the rubber composition for a tread for passenger cars, and the range of 10 to 120 parts by weight per 100 parts by weight of the rubber component is preferable. Moreover, when mix | blending a silica, it is preferable to mix | blend 5-50 weight part of carbon black, and the blend ratio of silica / carbon black is especially preferable 0.7 / 1-1 / 0.1. When silica is usually used as a filler, bis (3-triethoxysilylpropyl) tetrasulfide ("Si-69" manufactured by Degussa) or bis (3-triethoxysilylpropyl) disulfide ("Si-" manufactured by Degussa) 75 "), bis (3-diethoxymethylsilylpropyl) tetrasulfide, bis (3-diethoxymethylsilylpropyl) disulfide, octanethioic acid S- [3- (triethoxysilyl) propyl] ester (General Electronic Silicones) "NXT silane"), octanethioic acid S- [3-{(2-methyl-1,3-propanedialkoxy) ethoxysilyl} propyl] ester and octanethioic acid S- [3-{(2-methyl-1, 3-propanedialkoxy) methylsilyl} propyl] ester Rutriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-octyltrimethoxysilane , N-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3 -Methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-amino Til) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxy Silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyl It is preferable to add a compound having a functional group such as silicon or an element such as silicon that can be bonded to silica, such as one or more silane coupling agents selected from the group consisting of triethoxysilane, and bis (3 -Triethoxysilylpropyl) tetrasulfide (Degussa "Si- 69 ”), bis (3-triethoxysilylpropyl) disulfide (“ Si-75 ”manufactured by Degussa), and 3-octanoylthiopropyltriethoxysilane (“ NXT silane ”manufactured by General Electronic Silicones) are particularly preferable. Although the addition timing of these compounds is not particularly limited, it is preferably blended with the rubber component at the same time as silica, and the blending amount is preferably 2 to 10% by weight, more preferably 7 to 9% by weight, based on silica. It is. In the case of blending, the blending temperature is preferably 80 to 200 ° C, more preferably 110 to 180 ° C. Furthermore, when silica is used as the filler, in addition to silica, an element such as silicon that can be bonded to silica or a compound having a functional group such as alkoxysilane, monohydric alcohol such as ethanol, butanol, octanol, or ethylene Glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, pentaerythritol, polyether polyol and other dihydric alcohols, N-alkylamines, amino acids, liquid polybutadienes whose molecular ends are carboxyl-modified or amine-modified, etc. It is also preferable to mix.

Examples of the aluminum hydroxide include aluminum hydroxide having a nitrogen adsorption specific surface area of 5 to 250 m ² / g and a DOP oil supply amount of 50 to 100 ml / 100 g.

[Metal salt of S- (3-aminopropyl) thiosulfuric acid]
The metal salt of S- (3-aminopropyl) thiosulfuric acid used in the present invention has the following formula (1)
(H ₂ N— (CH ₂ ) ₃ —SSO ₃ ⁻ ) _n · M ^{n +} (1)
(In the formula, M ^{n +} represents a metal ion, and n represents its valence.)
It is a compound shown by these.

The metal ion represented by M ^{n +} is preferably a lithium ion, sodium ion, potassium ion, cesium ion, cobalt ion, copper ion or zinc ion, and more preferably a lithium ion, sodium ion or potassium ion. n represents the valence of the metal ion, and is not particularly limited as long as it is a possible range for the metal. For example, in the case of an alkali metal ion such as lithium ion, sodium ion, potassium ion or cesium ion, n is usually 1, n is usually 2 or 3 in the case of cobalt ion, and n is in the case of copper ion. Usually, it is an integer of 1 to 3, and in the case of zinc ion, n is usually 2.

  The weight of the metal salt of S- (3-aminopropyl) thiosulfuric acid is preferably 0.05 parts by weight or more and 2.5 parts by weight or less with respect to 100 parts by weight of the rubber component. By being in said range, the improvement effect of the viscoelastic property which concerns on the manufacturing method of this invention can be obtained preferably. Further, the use weight of the metal salt of S- (3-aminopropyl) thiosulfuric acid is more preferably 0.5 parts by weight or more and 1.0 part by weight or less with respect to 100 parts by weight of the rubber component.

  In addition, when the metal salt of S- (3-aminopropyl) thiosulfuric acid is blended in the pre-kneading step A, the temperature of the rubber component at the start of blending is 40 ° C. to 100 ° C., and the temperature of the rubber component at the end of blending is 110 ° C. or higher and 155 ° C. or lower.

  The median diameter of the metal salt of S- (3-aminopropyl) thiosulfuric acid is preferably 0.05 to 100 μm, more preferably 1 to 100 μm. Such median diameter can be measured by a laser diffraction method.

  The metal salt of S- (3-aminopropyl) thiosulfuric acid is obtained, for example, by reacting 3-halopropylamine with sodium thiosulfate; reacting phthalimide potassium salt with 1,3-dihalopropane. The compound can be produced by any known method such as a method of reacting the compound with sodium thiosulfate and then hydrolyzing the obtained compound.

  The metal salt can be isolated by operations such as concentration and crystallization, and the isolated metal salt usually contains about 0.1% to 5% of water.

  The metal salt of S- (3-aminopropyl) thiosulfuric acid can be previously blended with a support agent. Examples of such a carrier include the fillers exemplified above and “inorganic fillers and reinforcing agents” described on pages 510 to 513 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Carbon black, silica, fired clay and aluminum hydroxide are preferred. The amount of the carrier used is not particularly limited, but is preferably in the range of 10 to 1000 parts by weight per 100 parts by weight of the metal salt of S- (3-aminopropyl) thiosulfuric acid.

[Zinc oxide]
In the pre-kneading step A, it is preferable to knead the zinc oxide together with the rubber component. The amount of zinc oxide used is preferably in the range of 1 to 15 parts by weight, more preferably in the range of 3 to 8 parts by weight, per 100 parts by weight of the rubber component.

[Viscoelasticity improver]
It is possible to mix and knead an agent for improving viscoelastic properties (viscoelasticity improving agent) conventionally used in the rubber field in the pre-kneading step A and / or the post-kneading step B. What is necessary is just to add a viscoelasticity improving agent as needed.

  Examples of the viscoelasticity improver include N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), JP, Dithiouracil compounds described in JP-A-63-23942, nitrosoquinoline compounds such as 5-nitroso-8-hydroxyquinoline (NQ-58) described in JP-A-60-82406, “Tachylol (registered)” (Trademark) AP, V-200 "," Palwald "Baltuck 2, 3, 4, 5, 7, 710", etc., and the alkylphenol-sulfur chloride condensates described in JP2009-138148A, and bis ( 3-Triethoxysilylpropyl) tetrasulfide (Degussa “Si-69”), bis (3-triethoxysilylpropyl) disulfide Degussa “Si-75”), bis (3-diethoxymethylsilylpropyl) tetrasulfide, bis (3-diethoxymethylsilylpropyl) disulfide, octanethioic acid S- [3- (triethoxysilyl) propyl] ester , Octanethioic acid S- [3-{(2-methyl-1,3-propanedialkoxy) ethoxysilyl} propyl] ester and octanethioic acid S- [3-{(2-methyl-1,3-propanedialkoxy) Methylsilyl} propyl] ester phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysila , N-octyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, 3-methacryl Roxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, 2- (3,4-epoxycyclohexane) Sil) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and other silane coupling agents, 6-bis (N, N′-dibenzylthiocarbamoyldithio) hexane (“KA9188” manufactured by Bayer), 1,6-hexamethylenedithiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene ("Parkalink 900" manufactured by Flexis), 1-benzoyl-2-phenylhydrazide, 1- or 3-hydroxy-N '-(1-methylethylidene) -2-naphthoic acid hydrazide, JP-A-2004-91505 1- or 3-hydroxy-N ′-(1-methylpro Ridene) -2-naphthoic acid hydrazide, 1- or 3-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide and 1- or 3-hydroxy-N ′-(2-furylmethylene) ) Carboxylic acid hydrazide derivatives such as 2-naphthoic acid hydrazide, 3-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide, 3-hydroxy described in JP-A No. 2000-190704 -N '-(1,3-diphenylethylidene) -2-naphthoic acid hydrazide and 3-hydroxy-N'-(1-methylethylidene) -2-naphthoic acid hydrazide, bis described in JP-A-2006-328310 Mercaptooxadiazole compounds, pyrithione salt compounds described in JP2009-40898, JP2006 It includes cobalt hydroxide compounds described in 249361 JP.

  Among them, N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), 5-nitroso-8-hydroxyquinoline ( NQ-58), bis (3-triethoxysilylpropyl) tetrasulfide (“Si-69” manufactured by Degussa), bis (3-triethoxysilylpropyl) disulfide (“Si-75” manufactured by Degussa), 1, 6-bis (N, N′-dibenzylthiocarbamoyldithio) -hexane (“KA9188” manufactured by Bayer), hexamethylenebisthiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene (flexis Alkyl, such as “Parka Link 900” manufactured by the company, “Tacchirol (registered trademark) AP, V-200” manufactured by Taoka Chemical Phenol-sulfur chloride condensate is preferable.

  The use weight of the viscoelasticity improver is preferably in the range of 0.1 to 10 parts by weight per 100 parts by weight of the rubber component. By being in said range, the effect which improves a viscoelastic property can be acquired efficiently.

[Sulfur component]
Next, each substance used in the post-kneading process B will be described. Examples of the sulfur component include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Usually, powdered sulfur is preferred, and insoluble sulfur is preferred when used for tire members having a large amount of sulfur such as belt members. The sulfur component does not include S- (3-aminopropyl) thiosulfuric acid and its metal salt and vulcanization accelerator.

  The used weight of the sulfur component is preferably in the range of 0.3 to 10 parts by weight per 100 parts by weight of the rubber component, and preferably in the range of 0.5 to 5 parts by weight. More preferred. By being in said range, vulcanization | cure can be performed efficiently.

[Vulcanization accelerator]
Examples of vulcanization accelerators include thiazole vulcanization accelerators described on pages 412 to 413 of Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994), Examples thereof include sulfenamide vulcanization accelerators and guanidine vulcanization accelerators.

  Specifically, for example, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2 -Benzothiazolylsulfenamide (DCBS), 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), diphenylguanidine (DPG). Also, morpholine disulfide, which is a known vulcanizing agent, can be used.

  When carbon black is used as the filler, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclo Hexyl-2-benzothiazolylsulfenamide (DCBS) or dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) are preferably used in combination, and when silica and carbon black are used in combination as fillers N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2-benzothiazolylsulfate Fenamide (DCBS), dibenzothiazyl disulfide It is preferable that either of MBTS) in combination with diphenyl guanidine (DPG). The vulcanization accelerator does not include S- (3-aminopropyl) thiosulfuric acid and its metal salt.

  The weight of the vulcanization accelerator is not particularly limited. For example, it can be 0.1 parts by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the rubber component. Further, it is preferably 0.3 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the rubber component.

  By setting the weight of the vulcanization accelerator within the above range, the effect of improving the viscoelastic properties of the vulcanized rubber composition when a metal salt of S- (3-aminopropyl) thiosulfuric acid is used for kneading is obtained. Can be increased.

[Other ingredients]
Various compounding agents that can be blended in the kneading in the pre-kneading step A and / or the post-kneading step B are shown below. Examples of such compounding agents include anti-aging agents; oils; fatty acids such as stearic acid; Coumarone resin NG4 (softening point 81 to 100 ° C.) of Nittsu Chemical Co., Ltd., process resin of Kobe Oil Chemical Co., Ltd. Coumarone indene resin such as AC5 (softening point 75 ° C.); Terpene resin such as terpene resin, terpene phenol resin, and aromatic modified terpene resin; Mitsubishi Gas Chemical Co., Ltd. “Nikanol (registered trademark) A70” Rosin derivatives such as 70 to 90 ° C .; hydrogenated rosin derivatives; novolac alkylphenol resins; resole alkylphenol resins; C5 petroleum resins; liquid polybutadienes.

  Examples of the oil include process oil and vegetable oil. Examples of the process oil include paraffinic process oil, naphthenic process oil, and aromatic process oil.

  Examples of the anti-aging agent include those described in pages 436 to 443 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Among them, N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine (6PPD), reaction product of aniline and acetone (TMDQ), poly (2,2,4-trimethyl-1,2-) Dihydroquinoline (“Antioxidant FR” manufactured by Matsubara Sangyo Co., Ltd.), synthetic wax (paraffin wax, etc.) and vegetable wax are preferably used.

  Moreover, a chelating agent or a retarder may be blended and kneaded, and various general rubber chemicals or softeners may be blended and kneaded as necessary.

  Examples of the retarder include phthalic anhydride, benzoic acid, salicylic acid, N-nitrosodiphenylamine, N- (cyclohexylthio) -phthalimide (CTP), sulfonamide derivatives, diphenylurea, bis (tridecyl) pentaerythritol-diphosphite, etc. N- (cyclohexylthio) -phthalimide (CTP) is preferably used.

  The retarder may be blended and kneaded in the pre-kneading step A, but is preferably blended and kneaded in the post-kneading step B. The amount of the retarder used is not particularly limited, but is preferably in the range of 0.01 to 1 part by weight per 100 parts by weight of the rubber component. Especially preferably, it exists in the range of 0.05-0.5 weight part.

[Combination of each component]
According to the production method of the present invention, kneading is performed in the pre-kneading step A and the post-kneading step B, and the obtained kneaded product B is heat-treated in the heat treatment step C, thereby being used for various applications. A vulcanized rubber composition can be obtained.

  Of the rubber blends suitable for tread members suitable for trucks, buses, light trucks, and large construction tires, the rubber component is preferably natural rubber alone or a blend of SBR and / or BR containing natural rubber as a main component. As the filler, carbon black alone or a blend with carbon black containing silica as a main component is preferably used. Further, N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), 5-nitroso-8-hydroxyquinoline ( NQ-58), bis (3-triethoxysilylpropyl) tetrasulfide (Si-69), bis (3-triethoxysilylpropyl) disulfide (Si-75), 1,6-bis (N, N′-di) Benzylthiocarbamoyldithio) -hexane (“KA9188” manufactured by Bayer), hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene (“Parkalink 900” manufactured by Flexis), Taoka Viscosity of alkylphenol / sulfur chloride condensates such as chemical “Tacchirol (registered trademark) AP, V-200” It is preferable to use a sex modifier.

  Among rubber blends suitable for tread members suitable for passenger car tires, the rubber component includes, as a main component, solution-polymerized SBR having a molecular end modified with a silicon compound alone or the above-mentioned terminal-modified solution-polymerized SBR, and non-modified solution polymerization. A blend with at least one rubber selected from the group consisting of SBR, emulsion polymerization SBR, natural rubber and BR is preferred. Moreover, as a filler, the blend with carbon black which has a silica as a main component is used preferably. Further, N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), 5-nitroso-8-hydroxyquinoline ( NQ-58), bis (3-triethoxysilylpropyl) tetrasulfide (Si-69), bis (3-triethoxysilylpropyl) disulfide (Si-75), 1,6-bis (N, N′-di) Benzylthiocarbamoyldithio) -hexane (“KA9188” manufactured by Bayer), hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene (“Parkalink 900” manufactured by Flexis), Taoka Viscosity of alkylphenol / sulfur chloride condensates such as chemical “Tacchirol (registered trademark) AP, V-200” It is preferable to use a sex modifier.

  Among the rubber blends suitable for the sidewall member, the rubber component includes a blend of at least one rubber selected from the group consisting of BR as a main component, non-modified solution polymerization SBR, emulsion polymerization SBR, and natural rubber. preferable. Further, as the filler, carbon black alone or a blend with silica containing carbon black as a main component is preferably used. Further, N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), 5-nitroso-8-hydroxyquinoline ( NQ-58), bis (3-triethoxysilylpropyl) tetrasulfide (Si-69), bis (3-triethoxysilylpropyl) disulfide (Si-75), 1,6-bis (N, N′-di) Benzylthiocarbamoyldithio) -hexane (“KA9188” manufactured by Bayer), hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene (“Parkalink 900” manufactured by Flexis), Taoka Viscosity of alkylphenol / sulfur chloride condensates such as chemical “Tacchirol (registered trademark) AP, V-200” It is preferable to use a sex modifier.

  Among rubber blends suitable for carcass and belt members, the rubber component is preferably natural rubber alone or a blend with BR containing natural rubber as a main component. Further, as the filler, carbon black alone or a blend with silica containing carbon black as a main component is preferably used. Further, N, N′-bis (2-methyl-2-nitropropyl) -1,6-hexanediamine (“Sumifine (registered trademark) 1162” manufactured by Sumitomo Chemical Co., Ltd.), 5-nitroso-8-hydroxyquinoline ( NQ-58), bis (3-triethoxysilylpropyl) tetrasulfide (Si-69), bis (3-triethoxysilylpropyl) disulfide (Si-75), 1,6-bis (N, N′-di) Benzylthiocarbamoyldithio) -hexane (“KA9188” manufactured by Bayer), hexamethylene bisthiosulfate disodium salt dihydrate, 1,3-biscitraconimidomethylbenzene (“Parkalink 900” manufactured by Flexis), Taoka Viscosity of alkylphenol / sulfur chloride condensates such as chemical “Tacchirol (registered trademark) AP, V-200” It is preferable to use a sex modifier.

[Pre-kneading process A]
Below, each process which concerns on the manufacturing method of this invention is demonstrated. In the pre-kneading step A, the temperature at the start is 40 ° C. or higher and 100 ° C. or lower, and the temperature at the end is 110 ° C. or higher and 155 ° C. or lower. This is a step of kneading a metal salt of-(3-aminopropyl) thiosulfuric acid.

  In the pre-kneading step A, the order of blending the rubber component, the filler, and the metal salt of S- (3-aminopropyl) thiosulfuric acid is not particularly limited. The order of blending the metal salt of S- (3-aminopropyl) thiosulfuric acid is preferred.

  An example of a kneading apparatus that kneads each component is a Banbury mixer. The number of revolutions of the mixer during kneading varies depending on the type of rubber component used and the desired molecular weight, but can generally be 10 rpm or more and 100 rpm or less. Moreover, what is necessary is just to set the kneading | mixing time which kneads on the said temperature rising conditions suitably, and can generally be 3 minutes or more and 20 minutes or less.

  Thus, in the kneading process A, it is preferable to knead while heating each component by heating the mixer. Each component such as a rubber component is heated (or maintained at a predetermined temperature) by heat generated by kneading.

  In the pre-kneading step A, a rubber component, a filler, and a metal salt of S- (3-aminopropyl) thiosulfuric acid are blended and mixed under a temperature rising condition in which the temperature is increased from the starting temperature to the ending temperature. Perform smelting. The temperature at the start is 40 ° C. or more and 100 ° C. or less, and the temperature at the end is 110 ° C. or more and 155 ° C. or less.

  Specifically, the temperature at the start and the temperature at the end are the temperatures of the rubber components to be kneaded. The temperature at the start is the temperature of the rubber component when heating the rubber component, the filler, and the metal salt of S- (3-aminopropyl) thiosulfuric acid by the heating member. On the other hand, the temperature at the end is the temperature of the kneaded product A when the kneading of the rubber component, the filler, and the metal salt of S- (3-aminopropyl) thiosulfuric acid is finished. The temperature increase from the start temperature to the end temperature may be performed gradually as kneading progresses, or may be performed step by step at a predetermined temperature, for example, 5 ° C. The kneaded material A is obtained by kneading in this step.

  Conventionally, when kneading is performed, heating is usually performed at a temperature of 120 ° C. or higher. However, in the manufacturing method of the present invention, the initial temperature is 40 ° C. or higher and 100 ° C. or lower. Thus, the energy required for kneading can be reduced by kneading under a lower temperature condition. For this reason, it is possible to further reduce the load applied to the environment. Furthermore, the load on a manufacturing apparatus such as a mixer can be reduced. This has the effect of extending the life of the manufacturing apparatus.

  In the pre-kneading step A, a metal salt of S- (3-aminopropyl) thiosulfuric acid is used for kneading. By using the compound for kneading, even when kneading at low temperature, the finally obtained vulcanized rubber composition can have improved viscoelastic properties. Thus, the production method of the present invention can solve simultaneously the problem that can be carried out with low energy and the problem of improving the viscoelastic properties of the vulcanized rubber composition, and is very useful.

  Further, it is more preferable that the initial temperature is 80 ° C. or higher and 100 ° C. or lower and the end temperature is 135 ° C. or higher and 155 ° C. or lower. By performing the pre-kneading process A on the said temperature rising conditions, the viscoelastic characteristic of the vulcanized rubber composition obtained can be improved more preferably.

  When natural rubber is used as the rubber component, the pre-kneading step A may include a step of masticating the rubber component as a pre-stage of the pre-kneading step. The molecular chain of natural rubber is cut by mastication, which facilitates the processing of natural rubber.

[Post-kneading process B]
The post-kneading step B is a step of kneading the kneaded product A, the sulfur component and the vulcanization accelerator obtained in the pre-kneading step A. The post-kneading step B is preferably performed promptly after the kneading in the pre-kneading step A is completed.

  Examples of the kneading apparatus for kneading each component include an open mixer and a Banbury mixer.

  The temperature condition of the mixer setting in the post-kneading step is preferably 60 ° C. or higher and 120 ° C. or lower. The kneading time in the post-kneading step B may be appropriately changed according to the type of each component such as a rubber component, but as an example, it can be set to 0.5 minutes or more and 10 minutes or less. The kneaded product B can be obtained by further kneading in the post-kneading step B.

[Process to process kneaded material into a specific state]
Even if the manufacturing method of this invention includes the process step b which processes the kneaded material A obtained by the pre-kneading process A in a specific state between the post-kneading process B and the heat treatment process C. Good.

  Here, the “process for processing the kneaded product into a specific state” means, for example, in the field of tires, the step of coating the kneaded product on a steel cord, the step of coating a carcass fiber cord, “Process for processing into shape of tread member” and the like. In addition, processing shall include the process of shape | molding kneaded material.

  In addition, each member such as a belt, a carcass, an inner liner, a sidewall, and a tread (cap tread or under tread) respectively obtained by these steps is usually combined with other members by a method usually performed in the field of tires. Further, after being molded into the shape of the tire, that is, through a step of incorporating the kneaded product into the tire, a state of a raw tire including the kneaded product is obtained.

[Heat treatment step C]
The heat treatment step C is performed after the post-kneading step B or the processing step b. The kneaded product B obtained in the post-kneading step B or the molded product obtained in the processing step b is subjected to a heat treatment in the heat treatment step C. Such heat treatment is usually performed at normal pressure or under pressure.

  The temperature condition in the heat treatment in the heat treatment step C is preferably 120 ° C. or higher and 180 ° C. or lower. If the temperature is lower than 120 ° C, the vulcanization speed may be slow, and it may be difficult to determine the degree of vulcanization. If the temperature exceeds 180 ° C, the vulcanization speed may be high, and the vulcanization speed may be difficult to control. There is. Moreover, the suitable heating time (vulcanization time) in the heat treatment step C varies depending on the specific composition of the rubber composition.

  By the heat treatment, a vulcanized rubber composition can be obtained from the kneaded product obtained in the pre-kneading step A. On the other hand, when the heat treatment is performed after the processing step b, a molded product is obtained from the molded body.

  In addition, as an apparatus used for the heat treatment in the heat treatment step C, for example, a vulcanizer, a vulcanization press, a pressure press, or the like can be used.

  By using the vulcanized rubber composition thus obtained, a pneumatic tire can be produced by an ordinary method. That is, the rubber composition in the stage before the vulcanization treatment is extruded into a tread member, and is pasted and molded by a usual method on a tire molding machine to form a green tire. A tire can be obtained by heating and pressurizing.

[Physical properties of vulcanized rubber composition]
The viscoelastic properties of the vulcanized rubber composition are shown below.

<Viscoelastic properties>
The viscoelastic properties of the vulcanized rubber composition are determined from the loss coefficient (tan δ) calculated by changing the temperature and frequency conditions. When the loss factor at 60 ° C., which is a measure of rolling resistance, is small, the fuel efficiency of an automobile equipped with a tire obtained from a vulcanized rubber composition is good, and the loss factor at 0 ° C. is a measure of grip strength on wet roads Is large, it is considered that the braking performance of the automobile is good (page 124 of Non-Patent Document 1).

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention. The viscoelastic properties of the rubber compositions in the following examples and comparative examples were evaluated as follows.

(Viscoelastic properties)
Measurement was performed using a viscoelasticity analyzer manufactured by Ueshima Seisakusho. The loss coefficient (loss tangent) tan δ at 0 ° C., 20 ° C., 40 ° C., and 60 ° C. according to Examples and Comparative Examples was shown. tan δ is calculated from the equation tan δ = E ″ / E ′. E ′ is the storage elastic modulus and E ″ is the loss elastic modulus.

Measurement conditions: temperature -5 ° C to 80 ° C (temperature increase rate: 2 ° C / min), initial strain 10%, dynamic strain 2.5%, frequency 10 Hz
[Production Example 1]
Preparation of sodium salt of S- (3-aminopropyl) thiosulfuric acid:
The reaction vessel was purged with nitrogen, and 25 g (0.11 mol) of 3-bromopropylamine bromate, 28.42 g (0.11 mol) of sodium thiosulfate pentahydrate, 125 ml of methanol and 125 ml of water were placed in the reaction vessel. The resulting mixture was refluxed at 70 ° C. for 4.5 hours. The reaction mixture was allowed to cool and methanol was removed under reduced pressure. To the reaction mixture from which methanol had been removed, 4.56 g of sodium hydroxide was added and stirred at room temperature for 30 minutes. After completely removing the solvent under reduced pressure, 200 ml of ethanol was added and refluxed for 1 hour. Thereafter, sodium bromide as a by-product was removed by hot filtration. The filtrate was concentrated under reduced pressure until crystals precipitated, and then allowed to stand. The crystals were collected by filtration and washed with ethanol and hexane, and the crystals obtained were dried under vacuum to obtain sodium salt of S- (3-aminopropyl) thiosulfuric acid. The measurement result of ¹ H-NMR is shown below.

¹ H-NMR (270.05 MHz, MeOD) δ _ppm : 3.1 (2H, t, J = 6.3 Hz), 2.8 (2H, t, J = 6.2 Hz), 1.9-2. 0 (2H, m)
When measured by a laser diffraction method using a Shimadzu SALD-2000J type, the median diameter (50% D) of the sodium salt of S- (3-aminopropyl) thiosulfuric acid obtained was 66.7 μm. The sodium salt of S- (3-aminopropyl) thiosulfuric acid was pulverized so that the median diameter (50% D) was 14.6 μm and used in Example 1.

<Measurement operation>
The obtained sodium salt of S- (3-aminopropyl) thiosulfuric acid was added to a mixed solution of the following dispersion solvent (toluene) and a dispersant (10% by weight sodium di-2-ethylhexyl sulfosuccinate / toluene solution) at room temperature. The dispersion was stirred for 5 minutes while irradiating the obtained dispersion with ultrasonic waves to obtain a test solution. The test solution was transferred to a batch cell and measured after 1 minute (refractive index: 1.70-0.20i).

  The pH of an aqueous solution obtained by dissolving 10.0 g of sodium salt of S- (3-aminopropyl) thiosulfuric acid in 30 ml of water was 11-12.

[Example 1]
<Pre-kneading process A>
100 parts by weight of natural rubber (RSS # 1) was added to a Banbury mixer (600 ml Labo Plast Mill manufactured by Toyo Seiki Co., Ltd.) at a rpm of 25 rpm for 1 minute. The temperature of the heating member of the Banbury mixer was 40 ° C. Natural rubber put into a Banbury mixer was kneaded for 3 minutes at a rotation speed of a mixer of 50 rpm. Thereafter, while kneading the natural rubber at a mixer speed of 10 rpm, 45 parts by weight of carbon black (trade name “HAF Black N330” manufactured by Asahi Carbon Co., Ltd.), 3 parts by weight of stearic acid, zinc white (zinc oxide) ) 5 parts by weight and 0.4 part by weight of the sodium salt of S- (3-aminopropyl) thiosulfuric acid obtained in Production Example 1 were added to natural rubber.

  After adding the above carbon black into natural rubber, the temperature of the heating member of the Banbury mixer is set to 40 ° C. as the starting temperature, and further kneaded for 3 minutes while increasing the temperature, and then the rotation speed of the mixer is increased to 50 rpm. And kneaded for 5 minutes to obtain a kneaded product A. The temperature at the end of the heating member at the end of kneading was 120 ° C. As a result of heat generation by kneading, the temperature was 120 ° C. at the end of 5 minutes.

  Moreover, the temperature of the kneaded material at the time of kneading was 180-200 degreeC. Furthermore, the obtained kneaded material A was passed through an open roll having a set temperature of 50 to 60 ° C. and processed into a sheet shape.

<Post-kneading process B>
A kneaded product A obtained by the pre-kneading step A, 3 parts by weight of sulfur, a vulcanization accelerator (N-cyclohexyl-2-benzo) at a temperature of 60 to 80 ° C. in an open roll machine for 3 minutes. 1 part by weight of thiazolesulfenamide (CBS) and anti-aging agent (N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine: trade name “Antigen (registered trademark) 6C” manufactured by Sumitomo Chemical Co., Ltd. 1 part by weight was kneaded and blended to obtain a kneaded product B. Furthermore, the kneaded material B was processed into a 2.0 mm sheet. Thereafter, the kneaded product B was aged overnight (approximately 12 hours).

<Heat treatment step C>
Using a vulcanization press, the kneaded product B obtained in the post-kneading step B was vulcanized at 1145 ° C. for 15.5 minutes to obtain a vulcanized rubber composition. The viscoelastic property was measured with respect to the obtained vulcanized rubber composition. The viscoelastic properties are shown in Table 1.

[Comparative Example 1]
The temperature at the start was 40 ° C., the temperature at the end was 112 ° C., and the sodium salt of S- (3-aminopropyl) thiosulfuric acid was not blended in the pre-kneading step A, as in Example 1. Kneading was performed to obtain a vulcanized rubber composition. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

[Example 2]
Example 1 except that the temperature at the start was changed to 60 ° C., the temperature at the end was changed to 136 ° C., and the vulcanization time of the kneaded product B in the heat treatment step C was changed from 15.5 minutes to 16.0 minutes. Kneading was conducted in the same manner as above to obtain a vulcanized rubber product. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

[Comparative Example 2]
The temperature at the start is 60 ° C. and the temperature at the end is 135 ° C. In the pre-kneading step A, the sodium salt of S- (3-aminopropyl) thiosulfuric acid is not blended, and the kneaded product B in the heat treatment step C Kneading was carried out in the same manner as in Example 1 except that the vulcanization time was changed from 15.5 minutes to 17.5 minutes to obtain a vulcanized rubber composition. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

Example 3
Example 1 except that the temperature at the start was changed to 80 ° C., the temperature at the end was changed to 142 ° C., and the vulcanization time of the kneaded product B in the heat treatment step C was changed from 15.5 minutes to 15.0 minutes. Kneading was conducted in the same manner as above to obtain a vulcanized rubber product. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

[Comparative Example 3]
The temperature at the start is 80 ° C. and the temperature at the end is 137 ° C. In the pre-kneading step A, the sodium salt of S- (3-aminopropyl) thiosulfuric acid is not blended, and the kneaded product B in the heat treatment step C Kneading was carried out in the same manner as in Example 1 except that the vulcanization time was changed from 15.5 minutes to 16.0 minutes to obtain a vulcanized rubber composition. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

Example 4
Kneading was performed in the same manner as in Example 1 except that the temperature at the start was changed to 100 ° C. and the temperature at the end was changed to 154 ° C. to obtain a vulcanized rubber product. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

[Comparative Example 4]
The temperature at the start is 100 ° C. and the temperature at the end is 153 ° C. In the pre-kneading step A, the sodium salt of S- (3-aminopropyl) thiosulfuric acid is not blended, and the kneaded product B in the heat treatment step C Kneading was carried out in the same manner as in Example 1 except that the vulcanization time was changed from 15.5 minutes to 17.5 minutes to obtain a vulcanized rubber composition. In the same manner as in Example 1, viscoelastic properties of the obtained vulcanized rubber composition were measured. The viscoelastic properties are shown in Table 1.

  As shown in Table 1, when viscoelasticity specific tan δ of 0 ° C. to 80 ° C. is compared with Comparative Examples 1 to 4 corresponding to Examples 1 to 4, the values of the Examples are smaller at all temperatures. It turns out that was obtained. In particular, tan δ at 60 ° C., which is an index of fuel consumption, is 90.8% when Example 1 and Comparative Example 1 are compared, 94.8% when Example 2 and Comparative Example 2 are compared, and is compared with Example 3. When compared with Example 3, it is 77.3%, and when Example 4 is compared with Comparative Example 4, it is 85.7%. That is, according to the production method of the present invention, even if the kneading of the pre-kneading step A is performed at the temperature at the start and end of the low temperature, the metal of S- (3-aminopropyl) thiosulfuric acid The effect of blending the salt can improve tan δ at 60 ° C. of the resulting vulcanized rubber composition.

  On the other hand, in Examples 1 to 4, tan δ at 0 ° C. is larger than tan δ at 20 ° C. to 80 ° C. For example, when tan δ at 0 ° C. and tan δ at 80 ° C. in Example 1 are compared, tan δ at 0 ° C. has a larger value of 203.2%. Thus, tan δ at 0 ° C. in this example also shows a good value, and when the vulcanized rubber composition is used as a tire material for an automobile, the braking performance of the automobile can be improved. As described above, it is apparent that the vulcanized rubber composition obtained by the production method of the present invention has improved viscoelastic properties.

  Further, as in Examples 3 and 4, when the temperature at the start was 80 ° C. or more and 100 ° C. or less and the temperature at the end was in the range of 135 ° C. or more and 155 ° C. or less, Comparative Example 3 Compared to 4, tan δ at 60 ° C. is 77.3% and 85.7%, respectively, and tan δ at 60 ° C. is further reduced. That is, the fuel efficiency improvement effect of the automobile can be further increased, and it is shown that it is very useful.

  According to the present invention, it is possible to provide a vulcanized rubber composition having improved viscoelastic properties at low energy. Therefore, the present invention can be used in the field of using a rubber composition, particularly in the field of tires.

Claims (3)

A method for producing a vulcanized rubber composition comprising a rubber component, a filler, a metal salt of S- (3-aminopropyl) thiosulfuric acid, a sulfur component and a vulcanization accelerator,
Rubber components, fillers, S- (3-aminopropyl) under temperature rising conditions where the temperature at the start is 40 ° C. or more and 100 ° C. or less and the temperature at the end is 110 ° C. or more and 155 ° C. or less Pre-kneading step A for kneading a metal salt of thiosulfuric acid;
A post-kneading step B in which the kneaded product A obtained in the pre-kneading step A, the sulfur component and the vulcanization accelerator are kneaded;
A heat treatment step C for obtaining a vulcanized rubber by heat-treating the kneaded product B obtained in the post-kneading step B;
A process for producing a vulcanized rubber composition comprising:   2. The method for producing a vulcanized rubber composition according to claim 1, wherein the temperature at the start is 80 ° C. or more and 100 ° C. or less, and the temperature at the end is 135 ° C. or more and 155 ° C. or less.   The weight of the metal salt of S- (3-aminopropyl) thiosulfuric acid relative to 100 parts by weight of the rubber component is 0.05 parts by weight or more and 2.5 parts by weight or less. A process for producing a vulcanized rubber composition.