JP2012121980A - Modified homopolymeric diene rubber and method for producing the same, and rubber composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified homopolymeric diene polymer rubber well-balancedly excellent in mechanical properties, low energy loss tendency and abrasion resistance, to provide a method for producing the same, and to provide a rubber composition using the same.SOLUTION: The modified homopolymeric diene polymer rubber is such as to be obtained by reaction of an epoxidized homopolymeric diene rubber with an epoxidized rate of 0.1% or greater and less than 15% with an alkoxysilane having a functional group reactive with an epoxy group. The method for producing the modified homopolymeric diene polymer rubber is characterized by comprising: conducting a reaction, by mechanical kneading operation, of the epoxidized homopolymeric diene rubber having an epoxidized rate of 0.1% or greater and less than 15% with the alkoxysilane having a functional group reactive with an epoxy group.

Description

  The present invention relates to a modified homopolymer diene rubber, a method for producing the same, and a rubber composition using the same.

  In recent years, awareness of environmental issues has increased, and rubber materials for fuel-efficient tires have been actively developed for the purpose of improving the fuel efficiency of automobiles. Such rubber materials for tires aimed at low fuel consumption are desired to be excellent in mechanical properties, low energy loss and wear resistance. There is known a technique for reducing heat generation by improving friction and reducing friction between rubber molecules and between silica and rubber molecules. And in order to improve the dispersibility of a silica, many techniques which epoxidize-modify the rubber | gum used as the material are developed (patent document 1).

Japanese Patent No. 3363539

  However, the tire tread rubber composition described in Patent Document 1 does not necessarily have sufficient mechanical properties, low energy loss, and wear resistance. Accordingly, an object of the present invention is to provide a modified homopolymer diene rubber excellent in balance between mechanical properties, low energy loss and wear resistance, a method for producing the same, and a rubber composition using the same. .

  As a result of intensive studies to achieve the above object, the present inventors have found a modified homopolymer diene rubber obtained by reacting an epoxidized homopolymer diene rubber having a limited epoxidation rate with an alkoxysilane. It has been found that the mechanical properties, low energy loss and wear resistance can be improved in a balanced manner by using it, and the present invention has been achieved. That is, the present invention provides a modified homopolymer diene system obtained by reacting an epoxidized homopolymer diene rubber having an epoxidation rate of 0.1% or more and less than 15% with an alkoxysilane having a functional group that reacts with an epoxy group. Related to rubber.

  In the present invention, an epoxidized homopolymer diene rubber having an epoxidation rate of 0.1% or more and less than 15% and an alkoxysilane having a functional group that reacts with an epoxy group are reacted by mechanical kneading. The present invention relates to a method for producing a characteristic modified homopolymer diene rubber.

  Furthermore, the present invention relates to a modified homopolymer diene rubber composition comprising the above modified homopolymer diene rubber and silica.

  As described above, according to the present invention, there are provided a modified homopolymer diene rubber having excellent balance between mechanical properties, low energy loss and wear resistance, a method for producing the same, and a rubber composition using the same. be able to.

  In the modified homopolymer diene rubber according to the present invention, the homopolymer diene rubber used as a raw material is not particularly limited as long as it is a homopolymer, and a known one can be used. For example, natural rubber, butadiene rubber (BR), syndiotactic-1,2-polybutadiene-containing butadiene rubber (VCR), isoprene rubber, butyl rubber, chloroprene rubber and the like. Among these, butadiene rubber is particularly preferable.

  The homopolymer diene rubber has a weight average molecular weight (Mw) by GPC (gel permeation chromatography) of 50,000 to 2,000,000, 200,000 to 1,000,000, particularly 400,000 to 800,000. preferable. When the weight average molecular weight (Mw) is less than 50,000, the mechanical strength is lowered, and when it exceeds 2 million, the workability is deteriorated.

  The homopolymer diene rubber is epoxidized at an epoxidation rate of 0.1% to less than 15%, more preferably 0.2% to 5%, particularly preferably 0.5% to 2. %.

  The method for epoxidizing the homopolymer diene rubber is not particularly limited, and includes, for example, a method using monoperphthalic acid (Japanese Patent Laid-Open No. 51-060292), an organic peracid or a carboxylic acid anhydride thereof. Known methods such as a method using a hydrogen peroxide solution (Japanese Patent Laid-Open No. 05-214141), a method using a tungstic acid catalyst and a phosphoric acid compound, a phase transfer catalyst and a hydrogen peroxide solution (Japanese Patent No. 0392927) Is used.

  Examples of the method for adjusting the epoxidation rate during the epoxidation include ordinary methods such as adjusting the amount of hydrogen peroxide solution added, adjusting the reaction temperature, and adjusting the reaction time. . An epoxidation rate of less than 0.1% is not preferable in that the number of epoxy groups that react with an alkoxysilane having a functional group that reacts with an epoxy group is insufficient. In addition, when the epoxidation rate is 15% or more, it is preferable from the viewpoint that unsaturated bonds are reduced and rubber elasticity is lowered, and that when sulfur vulcanization is used, reversion is likely to occur and mechanical properties are lowered. Absent.

  In the modified homopolymer diene rubber according to the present invention, the alkoxysilane having a functional group that reacts with an epoxy group is not particularly limited, and an addition reaction can be performed on the epoxy group in the epoxidized homopolymer diene rubber. Anything is fine.

  Examples of the functional group that reacts with the epoxy group include amino group, mercapto group, vinyl group, ureido group, acryloxy group, isocyanate group, styryl group, methacryloxy group, sulfide group, nitro group, halogen group, epoxy group or glycidyl. A group having a thiocarbamoyl tetrasulfide structure, a benzothiazole tetrasulfide structure, or a methacrylate monosulfide structure.

  Examples of the alkoxysilane having a functional group that reacts with an epoxy group include 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3- Aminopropyldimethylethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethylbutoxysilane, 3-aminopropylmethyldibutoxysilane, 3- (2-aminoethylaminopropyl) Dimethoxymethylsilane, 3- (2-aminoethylaminopropyl) dimethoxyethylsilane, 3- (2-aminoethylaminopropyl) dimethoxypropylsilane, 3- (2-aminoethylaminopropyl) di Toxibutylsilane, 3- (2-aminoethylaminopropyl) diethoxymethylsilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 3- ( Those having an amino group, such as 2-aminoethylaminopropyl) tributoxysilane. Among these compounds, 3-aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) dimethoxymethylsilane, and 3- (2-aminoethylaminopropyl) trimethoxysilane are particularly preferable from the viewpoint of the modification effect. Preferably used.

  Furthermore, as an alkoxysilane having a functional group that reacts with an epoxy group, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, etc. Those having a mercapto group, those having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, those having a ureido group such as 3-ureidopropyltriethoxysilane, and acryloxy groups such as 3-acryloxypropyltrimethoxysilane Those having an isocyanate group such as 3-isocyanatopropyl and triethoxysilane, those having a styryl group such as p-styryltrimethoxysilane, and 3-methacryloxypropylmethyldi Those having a methacryloxy group such as toxisilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, bis Those having a sulfide group such as (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-nitropropyltrimethoxysilane, Those having a nitro group such as 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloro One having a halogen group such as tilt triethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxy Those having a thiocarbamoyl tetrasulfide structure such as silylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, benzothiazole tetrasulfides such as 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide Methacrylates such as those having a structure, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, diethoxy (3-glycidyloxypropyl) The thing etc. which have epoxy groups or glycidyl groups, such as methylsilane and 3-glycidyloxypropyl (dimethoxy) methylsilane, are mentioned. Among these compounds, alkoxysilanes having a glycidyl group or an epoxy group such as 3-glycidyloxypropyltrimethoxysilane are preferably used because the performance after reaction is particularly excellent.

  Furthermore, examples of the alkoxysilane having a functional group that reacts with an epoxy group include tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, triethylmethoxysilane, and tetraethoxy. Silane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, ethyltriethoxysilane, diethyldiethoxysilane, triethylethoxysilane, tetrabutoxysilane, methyltributoxysilane, dimethyldibutoxysilane, trimethylbutoxysilane, ethyltri Butoxysilane, diethyldibutoxysilane, triethylbutoxysilane, trimethoxysilane, methyldimethoxysilane, dimethylmethan Xysilane, ethyldimethoxysilane, diethylmethoxysilane, triethoxysilane, methyldiethoxysilane, dimethylethoxysilane, ethyldiethoxysilane, diethylethoxysilane, tributoxysilane, methyldibutoxysilane, dimethylbutoxysilane, ethyldibutoxysilane, Diethylbutoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, tetrapropoxysilane, methyltripropoxysilane, dimethyldipropoxysilane, ethyltripropoxy Examples include silane and diethyldipropoxysilane. Among these compounds, tetramethoxysilane and tetraethoxysilane are preferably used particularly from the viewpoint of both the effect of addition and cost.

  The alkoxysilane having a functional group that reacts with the epoxy group may be used alone or in combination of two or more.

  The amount of the alkoxysilane having a functional group that reacts with these epoxy groups is preferably 0.001 to 0.3 mol, more preferably 0.002 to 0.00 mol per 100 g of the epoxidized homopolymer diene rubber. 25 mol, particularly preferably 0.003 to 0.1 mol. When the amount of alkoxysilane used is less than 0.001 mol, the amount of alkoxysilane introduced into the epoxidized homopolymer diene rubber is reduced, and a satisfactory modification effect does not appear. On the other hand, when the amount of alkoxysilane used exceeds 0.3 mol, unreacted alkoxysilane remains in the epoxidized homopolymer diene rubber, which takes time to remove, and wastes alkoxysilane. Furthermore, the remarkable effect of improving physical properties is unlikely to appear.

  The modified homopolymer diene rubber according to the present invention comprises an epoxidized homopolymer diene rubber having an epoxidation rate of 0.1% or more and less than 15%, and an alkoxysilane having a functional group that reacts with an epoxy group. The reaction is characterized by mechanical kneading. For example, the reaction can be carried out by kneading alkoxysilane into an epoxidized homopolymer diene rubber as a raw material using a preheated kneader.

  As reaction temperature of the said reaction, 20 to 140 degreeC is preferable, More preferably, it is 40 to 120 degreeC. If it is less than 20 ° C, the reaction of the functional group of the epoxy group and the alkoxysilane does not occur, and if it exceeds 140 ° C, the homopolymer diene rubber is thermally deteriorated, which is not preferable.

  In the method for producing a modified homopolymer diene rubber according to the present invention, mechanical kneading is kneading a molten resin by applying a mechanical shearing force, and the kneading machine used for the kneading is mechanical shearing. There is no particular limitation as long as it is an apparatus capable of kneading molten resin by applying force, and it is used for resin processing such as roll kneader, Banbury mixer, pressure kneader, single screw extruder, twin screw extruder, twin screw taper extruder, etc. A general kneading machine can be used.

  According to the modified homopolymer diene rubber obtained by the method for producing a modified homopolymer diene rubber according to the present invention, mechanical properties, low energy loss and wear resistance can be improved in a well-balanced manner.

  Next, the rubber composition using the modified homopolymer diene rubber according to the present invention will be described. The rubber composition according to the present invention is characterized by containing the modified homopolymer diene rubber and silica.

  In the rubber composition according to the present invention, in addition to the modified homopolymer diene rubber, other rubbers may be added and used as a rubber composition. There is no restriction | limiting in particular as rubber | gum other than that added, A well-known thing can be used. For example, polymers of diene monomers such as natural rubber, butadiene rubber (BR), syndiotactic-1,2-polybutadiene-containing butadiene rubber (VCR), isoprene rubber, butyl rubber, chloroprene rubber; acrylonitrile butadiene rubber ( NBR), acrylonitrile-diene copolymer rubber such as nitrile chloroprene rubber, nitrile isoprene rubber; styrene-diene copolymer rubber such as styrene butadiene rubber (SBR), styrene chloroprene rubber, styrene isoprene rubber; ethylene propylene diene rubber (EPDM), etc. Is mentioned. Of these, butadiene rubber, syndiotactic-1,2-polybutadiene-containing butadiene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, natural rubber, and isoprene rubber are preferable. These can be used alone or in combination of two or more.

  In the rubber composition according to the present invention, the content of silica is 10 to 120 parts by weight, more preferably 30 parts by weight based on 100 parts by weight of the modified homopolymer diene rubber and other rubber components. Part to 90 parts by weight, particularly preferably 50 parts to 80 parts by weight. If the amount of silica is less than 10 parts by weight, sufficient silica dispersion can be obtained without using the modified homopolymer diene rubber of the present invention. Therefore, there is no effect of the present invention. This is not preferable because it is extremely worse and wear resistance is also lowered.

  Moreover, a rubber reinforcing agent can be added to the rubber composition according to the present invention. Examples of the rubber reinforcing agent include various types of carbon black, white carbon, activated calcium carbonate, ultrafine magnesium silicate and the like in addition to the above silica. Among them, preferably, carbon black having a particle size of 90 nm or less and dibutyl phthalate (DBP) oil absorption of 70 ml / 100 g or more, for example, FEF, FF, GPF, SAF, ISAF, SRF, HAF and the like are used. Particularly preferred is ISAF having a small particle size from the viewpoint of low heat build-up and low fuel consumption.

  When carbon black and silica used for the rubber reinforcing agent are mixed, it becomes possible to achieve both workability, low energy loss and wear. In particular, the weight ratio of carbon black / silica is preferably 90/10 to 10/90, more preferably 80/20 to 20/80, and particularly preferably 70/30 to 30/70. If the amount of silica is less than 10%, energy loss increases, and if it is more than 90%, there is a drawback that workability and wear resistance are deteriorated.

  Moreover, a vulcanizing agent and a vulcanization accelerator can be further added to the rubber composition according to the present invention.

  Examples of the vulcanizing agent include sulfur, a compound that generates sulfur by heating, a metal oxide such as an organic peroxide and magnesium oxide, a polyfunctional monomer, and a silanol compound. Examples of the compound that generates sulfur by heating include tetramethyl thiuram disulfide and tetraethyl thiuram disulfide.

  Examples of the vulcanization accelerator include aldehydes, ammonia, amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, xanthates, and more specifically, tetramethylthiuram disulfide. (TMTD) N-oxydiethylene-2-benzothiazolylsulfenamide (OBS), N-cyclohexyl-2-benzothiazylsulfenamide (CBS), dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole ( MBT), zinc di-n-butyldithiocarbite (ZnBDC), zinc dimethyldithiocarbide (ZnMDC) and the like.

  Moreover, the rubber composition which concerns on this invention can add well-known additives normally used for rubber compositions, such as anti-aging agent, a filler, a process oil, as needed.

  Anti-aging agents include amine / ketone-based, imidazole-based, amine-based, phenol-based, sulfur-based and phosphorus-based anti-aging agents. More specifically, as the anti-aging agent, phenol-based 2,6-di-t-butyl-p-cresol (BHT), phosphorus-based trinonylphenyl phosphite (TNP), sulfur-based 4,6- Bis (octylthiomethyl) -o-cresol, dilauryl-3,3′-thiodipropionate (TPL) and the like can be mentioned.

  Examples of fillers include inorganic fillers such as calcium carbonate, basic magnesium carbonate, clay, Lissajous, diatomaceous earth, and other fillers such as recycled rubber and powder rubber. Process oils include aromatic and naphthenic fillers. And paraffinic process oil.

  Furthermore, a silane coupling agent may be added to the rubber composition according to the present invention. As the silane coupling agent, a silane coupling agent having a functional group capable of reacting with an epoxy group is particularly preferable.

  Examples of commercially available silane coupling agents having a functional group capable of reacting with an epoxy group include, but are not limited to, the following. 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropylmethyldiethoxysilane, 3 -Aminopropyltriethoxysilane, 3-aminopropyldimethylbutoxysilane, 3-aminopropylmethyldibutoxysilane, 3- (2-aminoethylaminopropyl) dimethoxymethylsilane, 3- (2-aminoethylaminopropyl) dimethoxyethyl Silane, 3- (2-aminoethylaminopropyl) dimethoxypropylsilane, 3- (2-aminoethylaminopropyl) dimethoxybutylsilane, 3- (2-aminoethylaminopropyl) diethoxy Methylsilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (2-aminoethylaminopropyl) triethoxysilane, 3- (2-aminoethylaminopropyl) tributoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, (3-mercaptopropyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane, (3-mercaptopropyl) methyldimethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 11- Mercaptoethyloleates undecyl trimethoxysilane, and the like 11 mercaptoundecyl triethoxysilane. Among these, (3-mercaptopropyl) triethoxysilane is particularly preferable.

  The addition amount of the silane coupling agent having a functional group capable of reacting with an epoxy group is preferably 0.1 to 1 molar equivalent with respect to the number of epoxy groups of the epoxidized diene rubber. When the addition amount of the silane coupling agent is less than 0.1 molar equivalent, the effect of improving tan δ and wear resistance tends to be reduced. Moreover, when the addition amount of the said silane coupling agent exceeds 1 molar equivalent, there exists a tendency which is not economically preferable.

  A rubber composition using a silane coupling agent functions to improve the dispersibility of the rubber reinforcing agent in the rubber matrix by mixing with a rubber reinforcing agent such as silica. As a result, it also leads to effects such as low fuel consumption.

  In the rubber composition according to the present invention, the maximum temperature during kneading using the banbury, open roll kneader, kneader, biaxial kneader, etc., in which each of the above components is usually performed, is the silane coupling agent and the epoxy group. It can be obtained by kneading under the condition of the reaction temperature or higher.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, these do not limit the objective of this invention.

(Reference example)
First, an epoxidized polybutadiene rubber used in this example was produced. Specifically, 100 g of diene rubber (manufactured by Ube Industries Co., Ltd .: UBEPOL BR150L) is taken, put into 1000 cc of cyclohexane in a separable flask and stirred, and dissolved overnight (about 8 hours). did. Thereafter, the temperature of the separable flask was set to 50 ° C. in a water bath, and 1 g of nonionic surfactant Telic 320 (manufactured by HUNTSMAN) and 4.25 g of formic acid were added and stirred, followed by hydrogen peroxide solution (30%) 10 0.5 g was added with a dropping funnel and stirring was continued for 2 hours. Thereafter, the heating was stopped, 0.1 g of antioxidant Irganox 1520L was added, and ice was added into the water bath to lower the temperature to room temperature. Next, 500 ml of methanol was added to precipitate epoxidized polybutadiene rubber from the solution. After removing the solvent, 500 cc of 2.5% sodium carbonate was added, and after stirring for 10 minutes, the washing solution was removed. Further, 500 cc of water was added, and after stirring for 10 minutes, the cleaning solution was removed. This washing operation was performed three times. Then, the reaction solution was taken out into a vat coated with Teflon (registered trademark), placed in a vacuum dryer at 90 ° C. for 1 hour, and dried to obtain an epoxidized polybutadiene rubber according to a reference example.

  When the epoxidation rate of the obtained epoxidized polybutadiene rubber was measured, it was 5.0%.

  The epoxidation rate was measured according to JIS K7236 after storing for 3 hours or more after the completion of the sample process. The difference from JIS K7236 is that the amount of epoxidized rubber was 0.6 to 0.9 g, and the amount of chloroform used when dissolving the epoxidized rubber was 20 ml. According to JIS K7236, 20 ml of acetic acid is added immediately before the measurement, but no acetic acid other than acetic acid contained in the tetraethylammonium bromide acetic acid solution is added. When a standard amount of acetic acid was added, a rubber having a low epoxidation rate was precipitated in a lump and could not be titrated. When the amount of acetic acid was reduced, the equivalence point became difficult to understand, but the precipitated sample spread on the measurement liquid in the form of an oil film, and titration became possible if time was taken. Other reagent adjustments are as described in JIS K7236.

  Moreover, the epoxidation rate was computed using the following formula 1 here. The epoxy equivalent is the mass (g) of the epoxidized resin corresponding to 1 mol of the epoxy group, and is determined by the method described in JIS K7236. In the case of 100% epoxidized polybutadiene, it is butadiene molecular weight + oxygen 1 atomic weight.

Example 1
Next, 100 g of the epoxidized polybutadiene rubber produced in the reference example was taken, wound around a roll (temperature: 60 ° C., roll interval: 0.8 mm), and kneaded. As the roll, a 6-inch roll kneader manufactured by Yasuda Seiki was used. Next, 1 g of GOPTMS (3-glycidyloxypropyltrimethoxysilane) (manufactured by Tokyo Kasei Co., Ltd .: reagent) is hung on the epoxidized polybutadiene rubber on the roll by using a pipette, and further kneaded for 5 minutes, thereby relating to Example 1. A modified homopolymer polybutadiene rubber was obtained. The modified homopolymer polybutadiene rubber was allowed to stand for 24 hours, and about 5 g was taken, dissolved in 100 ml of cyclohexane, and precipitated with ethanol twice. The obtained sample was again dried at 90 ° C. for 1 hour, and the Si pigment was measured by ICP analysis. The results are shown in Table 1.

  Further, a 180 cc Banbury type plastmill was preheated to 90 ° C., 30 parts by weight of the modified homopolymer polybutadiene rubber obtained in Example 1 and a styrene-butadiene rubber (styrene content: 23%, ML1 + 4, 100 ° C .: 70) 70 parts by weight was put into a plast mill and kneaded for 30 seconds. Subsequently, 6 parts by weight of silane coupling agent Si69, 75 parts by weight of silica (nip seal AQ), 21.5 parts by weight of process oil, 3 parts by weight of zinc, and 2 parts by weight of anti-aging agent Antigen 6C (manufactured by Sumitomo Chemical), 1 part by weight of stearic acid was mixed, half of which was put into a plastmill and kneaded for 1 minute. Next, the remaining half was added and kneaded for about 3 minutes for 30 seconds. After a total of 5 minutes from the start of kneading, the kneaded product was taken out from the plast mill. Next, 1.4 parts by weight of sulfur as a vulcanizing agent, 1.7 parts by weight of a vulcanization accelerator Noxeller CZ and 2 parts by weight of Noxeller D were added while the mixture taken out around a 6-inch roll was wound and kneaded in a roll. . The roll temperature was 60 ° C., and sulfur and the vulcanization accelerator were mixed for about 5 minutes. After allowing the mixture to stand for 1 day, a part of the mixture was sampled and the compound Mooney viscosity was measured. Next, vulcanization molding was performed in order to obtain a vulcanization molded body necessary for the test described in Table 1. Using a mold set in a hot press, the mixture was placed in the mold and vulcanized by heating and pressurizing at a temperature of 160 ° C. for about 20 to 25 minutes to obtain a rubber composition according to Example 1. Table 2 shows the chemicals used and the mixing ratio (parts by weight).

  In Table 1 above, the tensile strength, rolling resistance index (tan δ index), and lamborn wear index of the rubber composition were measured by the following methods.

(Compound ML (Mooney viscosity of the compound (ML1 + 4, 100 ° C.)))
According to JIS K6300, after preheating at 100 ° C. for 1 minute, the Mooney viscosity (ML1 + 4, 100 ° C.) of the unvulcanized rubber composition measured for 4 minutes was expressed by the following formula 2. The larger the index, the lower the viscosity and the better.

(Tensile test)
Measurement was performed according to JIS K6301, and the tensile strength and fracture elongation were indicated by the following formula (3) as an index. Generally, the larger the index, the more advantageous as a rubber composition.

(Tan δ index)
Using EPLEXOR 100N (manufactured by GABO), tan δ of each formulation was measured under the measurement conditions of initial strain 10%, dynamic strain 0.3%, frequency 16 Hz, temperature 50 ° C., and tan δ of Comparative Example 1 was set to 100. Indicated by an index using the following formula 4. The larger the index, the better the rolling resistance characteristics.

(Lambourn wear index)
Using a Lambourn wear tester, measure the Lambourn wear amount under the measurement conditions of a temperature of 20 ° C., a slip rate of 60%, and a test time of 5 minutes, calculate the volume loss of each formulation, and set the loss amount of Comparative Example 1 to 100 Indicated by an index using the following formula (5). It shows that abrasion resistance is excellent, so that an index | exponent is large.

(Comparative Example 1)
Next, the epoxidized polybutadiene rubber used in Example 1 was changed to polybutadiene rubber (manufactured by Ube Industries, Ltd .: UBEPOL BR150L), and the Si content was measured by ICP analysis without washing with cyclohexane. Moreover, each physical property value of the rubber composition was measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
Next, polybutadiene rubber (manufactured by Ube Industries, Ltd .: UBEPOL BR150L) is dissolved in 1000 cc of cyclohexane, GOPTMS (manufactured by Tokyo Chemical Industry: 3-glycidylpropyltrimethoxysilane) is added, and the mixture is stirred at 80 ° C. for 30 minutes. And the modified homopolymer polybutadiene rubber which concerns on the comparative example 2 was obtained by making it precipitate with ethanol and making it dry at 90 degreeC. The Si content of this modified homopolymer polybutadiene rubber was measured in the same manner as in Example 1. Moreover, each physical property value of the rubber composition was measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
Next, the Si content and each physical property value of the rubber composition were measured in the same manner as in Example 1 except that the epoxidized polybutadiene rubber produced in Reference Example was used as it was without modification. The results are shown in Table 1.

(Comparative Example 4)
Next, the epoxidized polybutadiene rubber produced in the reference example is dissolved in 1000 cc of cyclohexane, GOPTMS (manufactured by Tokyo Chemical Industry: Reagent) is added, stirred at 80 ° C. for 30 minutes, precipitated with ethanol, and dried at 90 ° C. Thus, a modified homopolymer polybutadiene rubber according to Comparative Example 4 was obtained. The Si content of this modified homopolymer polybutadiene rubber was measured in the same manner as in Example 1. Moreover, each physical property value of the rubber composition was measured in the same manner as in Example 1. The results are shown in Table 1.

  As described above, since the modified homopolymer polybutadiene rubber according to the example has a large amount of Si reacted with an epoxy group, the dispersibility of silica is improved, and as a result, Tan δ, tensile strength, breaking elongation, and It can be seen that the wear resistance is improved in a well-balanced manner.

Claims (4)

  A modified homopolymer diene rubber obtained by reacting an epoxidized homopolymer diene rubber having an epoxidation rate of 0.1% or more and less than 15% with an alkoxysilane having a functional group that reacts with an epoxy group.   The modified homopolymer diene rubber according to claim 1, wherein the reaction is carried out at 20 to 140 ° C.   A modified single weight characterized in that an epoxidized homopolymer diene rubber having an epoxidation rate of 0.1% or more and less than 15% is reacted with an alkoxysilane having a functional group that reacts with an epoxy group by mechanical kneading. A method for producing a combined diene rubber. A modified homopolymer diene rubber composition comprising the modified homopolymer diene rubber according to claim 1 or 2 and silica.