JP2002179841A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which can be made into a vulcanized rubber which is excellent in processability, has low rolling resistance and the like, and has sufficient abrasion resistance and the like. SOLUTION: (1) A conjugated diene-based rubber comprising a specific quantitative ratio of an olefinically unsaturated nitrile monomer unit, an aromatic vinyl monomer unit and a conjugated diene monomer unit as a repeating unit. A rubber composition comprising: a rubber component comprising: (2) an inorganic filler such as silica; and (3) a compound having at least one polymerizable unsaturated group and a specific functional group such as an amino group. . The molecular weight of this compound is 200
It is preferable that it is above. The conjugated diene rubber has at least one polymerizable unsaturated group as a repeating unit,
It may have a monomer unit having a specific functional group such as an amino group, and may be oil-extended with an extending oil in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rubber composition having a specific composition. More specifically, when blended with an inorganic filler such as silica as a reinforcing agent, excellent workability,
The present invention also relates to a rubber composition which has low rolling resistance, high wet skid resistance, and can be a vulcanized rubber having sufficient abrasion resistance and the like. This vulcanized rubber is particularly useful as a tire tread or the like.

[0002]

2. Description of the Related Art With the recent demand for low fuel consumption of automobiles, tires having low rolling resistance, excellent breaking characteristics and abrasion resistance, and high wet skid resistance which is a representative index of steering stability. There is a need for raw rubbers such as conjugated diene rubbers from which rubber compositions can be prepared.

[0003] In order to reduce the rolling resistance of a tire, the hysteresis loss of the vulcanized rubber may be reduced. This hysteresis loss can be evaluated using various physical properties as indices. For example, a raw rubber having a large rebound resilience at 50 to 80 ° C., a small tan δ at 50 to 80 ° C., or a small Goodrich heat generation is preferable. Examples of the raw rubber having a small hysteresis loss include natural rubber, isoprene rubber, and butadiene rubber, but these have a problem that wet skid resistance is small.

In recent years, there has been proposed a method of using an inorganic filler such as silica as a reinforcing agent in a rubber composition for a tire, or using an inorganic filler and carbon black in combination. A tire tread using an inorganic filler or a combination of an inorganic filler and carbon black has low rolling resistance and excellent steering stability represented by wet skid resistance. However, there is a problem that the vulcanized rubber is inferior in wear resistance and tensile strength. One reason for this is considered to be that the affinity of the inorganic filler for the conjugated diene rubber is lower than that of carbon black, and a sufficient reinforcing effect cannot be obtained.

[0005] In particular, when the inorganic filler is silica,
In order to increase the affinity with the conjugated diene rubber, it has been conventionally studied to use a conjugated diene rubber into which a functional group having an affinity for silica is introduced. For example, a conjugated diene rubber having a hydroxyl group introduced therein (WO 96/23027)
Japanese Patent Application Laid-Open No. 9-208633), a conjugated diene rubber having an alkoxysilyl group introduced therein (JP-A-9-208623), and a conjugated diene rubber having an alkoxysilyl group and an amino group or a hydroxyl group introduced therein (JP-A-9-208633). Have been. However, many of the conjugated diene-based rubbers introduced with these functional groups have a strong interaction with silica, causing problems such as poor dispersion when mixed with silica, large heat generation during processing, and poor processability. have.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, is excellent in workability, has low rolling resistance, has high wet skid resistance, and has sufficient wear resistance. It is an object of the present invention to provide a rubber composition having a tensile strength and the like, and which can be used as a vulcanized rubber useful as an automobile tire tread or the like.

[0007]

A rubber composition for forming a tire tread or the like usually contains a reinforcing agent for improving abrasion resistance, tensile strength and the like, but silica and the like are liable to agglomerate. It is not easy to disperse evenly. When a rubber composition in which the reinforcing agent is not uniformly dispersed is used, not only the desired effect of blending the reinforcing agent is not obtained, but also the processability may be reduced.
Therefore, dispersibility is generally improved by a method such as blending a silane coupling agent.

However, in order to obtain a sufficient effect, it is necessary to use a large amount of an expensive silane coupling agent.
Further, there is a problem that the kneading temperature at the time of compounding must be suppressed to 150 to 160 ° C. or less. In order to solve these problems, the composition of the rubber composition was examined.By using a rubber composition in which a compound having a specific functional group was compounded, it was excellent even without compounding a silane coupling agent. It has been found that they have improved processability and can sufficiently improve the wear resistance and the like of the vulcanized rubber. The present invention has been made based on such findings.

The rubber composition according to claim 1 is [1] 30
A rubber component containing a conjugated diene-based rubber in an amount of not less than mass%, [2]
A rubber composition containing an inorganic filler and [3] a compound having at least one polymerizable unsaturated group and at least one functional group among an amino group, a hydroxyl group, an epoxy group, and a carboxyl group. When the rubber component is 100 parts by mass, the inorganic filler is 20 to 1
50 parts by mass, and the compound is 0.1 to 20 parts by mass.

The above-mentioned "conjugated diene rubber" has a conjugated diene monomer unit as a monomer unit, and includes natural rubber (NR), isoprene rubber (IR), low cis-butadiene rubber (BR), Cis BR, high trans BR, solution polymerized styrene-butadiene copolymer rubber (SBR), emulsion polymerized SBR, styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-
Butadiene copolymer rubber (SIBR), acrylonitrile-butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber (NSBR), NSBR having a functional group, and the like.

These conjugated diene rubbers can be appropriately selected and used according to the required characteristics, and may be used alone or in combination of two or more. As the conjugated diene rubber, NSBR, NSBR having a functional group, NR, IR, BR, SBR, and SIBR are preferable, and NSBR and NSBR having a functional group are particularly preferable in terms of both processability and physical properties.

Hereinafter, the NSBR and the NSBR having a functional group will be described in detail. As described in claim 2, NSBR contains 1 to 30% by mass of (1) an olefinically unsaturated nitrile monomer (hereinafter, referred to as a monomer) unit as a repeating unit, and (2) an aromatic vinyl monomer unit. 10 to 50% by mass of a monomer unit (hereinafter, referred to as a monomer) and 20 to 89% by mass of (3) a conjugated diene monomer (hereinafter, referred to as a monomer) unit. In addition, NSBR having a functional group is a monomer,
, And a monomer having one polymerizable unsaturated group and at least one functional group of an amino group, a hydroxyl group, an epoxy group, and a carboxyl group (hereinafter, referred to as a monomer) ) Unit 10 parts by mass (hereinafter abbreviated as “parts”).
The total amount of (2) and (3) is set to 100 parts. ]. These NSBR and NSBR having a functional group are a monomer,
, And a random copolymer obtained by copolymerizing a monomer as required.

Examples of the monomer include acrylonitrile, methacrylonitrile and the like. One of these monomers may be used alone, or two or more thereof may be used in combination. In the repeating unit of NSBR and NSBR having a functional group, the content of a unit composed of a monomer is 1 to 30% by mass, and particularly preferably 5 to 20% by mass. When the unit composed of the monomer is less than 1% by mass, the interaction with the inorganic filler or the like is reduced, and the abrasion resistance and the like are not sufficiently improved. 30 units composed of monomers
If the amount exceeds 50% by mass, the low-temperature properties of a vulcanized rubber are undesirably reduced.

As the monomers, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene,
α-methylstyrene, 2,4-dimethylstyrene, 2,
4-diisopropylstyrene, 4-tert-butylstyrene, tert-butoxystyrene and the like.
One of these monomers may be used alone, or two or more thereof may be used in combination. In the NSBR and the NSBR having a functional group, the content of the monomer unit is 1
It is preferably 0 to 50% by mass, particularly preferably 20 to 40% by mass. If the unit composed of a monomer is less than 10% by mass, the abrasion resistance may decrease. If the unit composed of a monomer exceeds 50% by mass, the rebound resilience tends to decrease and tan δ tends to increase.

The monomers include 1,3-butadiene,
Isoprene, 2,3-dimethyl-1,3-butadiene,
Chloroprene and the like. One of these monomers may be used alone, or two or more thereof may be used in combination. The content of the unit consisting of the monomer in NSBR and NSBR having a functional group is 20 to 89% by mass,
In particular, it is preferably from 40 to 80% by mass. When the unit composed of a monomer is less than 20% by mass, the rebound resilience becomes small and tan δ may become large, which is not preferable.

Among the monomers, the monomer having an amino group is preferably a monomer having a tertiary amino group.
(A) dimethylaminomethyl (meth) acrylate, diethylaminomethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2- (di-n-propylamino) ethyl (meth) ) Acrylate, 2-dimethylaminopropyl (meth) acrylate, 2-diethylaminopropyl (meth) acrylate, 2- (di-n-
Propylamino) propyl (meth) acrylate, 3-
Dialkylaminoalkyl (meth) acrylates such as dimethylaminopropyl (meth) acrylate, 3-diethylaminopropyl (meth) acrylate, and 3- (di-n-propylamino) propyl (meth) acrylate;

(B) N-dimethylaminomethyl (meth)
Acrylamide, N-diethylaminomethyl (meth) acrylamide, N- (2-dimethylaminoethyl) (meth) acrylamide, N- (2-diethylaminoethyl) (meth) acrylamide, N- (2-dimethylaminopropyl) (meth) Acrylamide, N- (2-diethylaminopropyl) (meth) acrylamide, N-
N-dialkylaminoalkyl group-containing unsaturated amides such as (3-dimethylaminopropyl) (meth) acrylamide, N- (3-diethylaminopropyl) (meth) acrylamide,

(C) N, N-dimethyl-p-aminostyrene, N, N-diethyl-p-aminostyrene, dimethyl (p-vinylbenzyl) amine, diethyl (p-vinylbenzyl) amine, dimethyl (p- Vinylphenethyl) amine, diethyl (p-vinylphenethyl) amine, dimethyl (p-vinylbenzyloxymethyl) amine, dimethyl [2- (p-vinylbenzyloxy) ethyl] amine, diethyl (p-vinylbenzyloxymethyl) amine , Diethyl [2- (p-vinylbenzyloxy) ethyl] amine, dimethyl (p-vinylphenethyloxymethyl) amine, dimethyl [2- (p-vinylphenethyloxy) ethyl] amine, diethyl (p-vinylphenethyloxymethyl) amine ) Amine, diethyl [2-
(P-vinylphenethyloxy) ethyl] amine, 2-
And tertiary amino group-containing vinyl aromatic compounds such as vinylpyridine, 3-vinylpyridine and 4-vinylpyridine. Of these, dialkylaminoalkyl (meth) acrylates and tertiary amino group-containing vinyl aromatic compounds are preferred. One of these monomers having an amino group may be used alone, or two or more thereof may be used in combination.

Among the monomers, monomers having a hydroxyl group include (a) 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acryle
G, 2-hydroxybutyl (meth) acrylate, 3-
Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate;

(B) mono (meth) acrylates of polyalkylene glycols (the number of alkylene glycol units is, for example, 2 to 23) such as polyethylene glycol and polypropylene glycol, (c) N-hydroxymethyl (meth) acrylamide, Hydroxyl group-containing unsaturated amides such as N- (2-hydroxyethyl) (meth) acrylamide, N, N-bis (2-hydroxyethyl) (meth) acrylamide;

(D) o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, o-hydroxy-α-methylstyrene, m-hydroxy-α-methylstyrene, p-hydroxy-α-methylstyrene, p-hydroxystyrene
A hydroxyl group-containing vinyl aromatic compound such as vinylbenzyl alcohol, (e) (meth) allyl alcohol,
And the like. Of these, hydroxyalkyl (meth) acrylates and hydroxyl group-containing vinyl aromatic compounds are preferred. One of these monomers having a hydroxyl group may be used alone, or two or more thereof may be used in combination.

Among the monomers, monomers having an epoxy group include (meth) allyl glycidyl ether, glycidyl (meth) acrylate, 3,4-oxycyclohexyl (meth) acrylate and the like. One of these monomers having an epoxy group may be used alone, or two or more thereof may be used in combination.

Among the monomers, the monomers having a carboxyl group include (a) unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, tetraconic acid, and cinnamic acid; These salts, (b) non-polymerizable polycarboxylic acids such as phthalic acid, hexahydrophthalic acid, succinic acid and adipic acid, and non-hydroxyl-containing carboxylic acids such as (meth) allyl alcohol and 2-hydroxyethyl (meth) acrylate Free carboxyl group-containing esters such as monoesters with saturated compounds and salts thereof. Of these, unsaturated carboxylic acids are preferred. One of these monomers having a carboxyl group may be used alone, or two or more thereof may be used in combination.

The content of the monomer unit in NSBR having a functional group is 10 parts or less, particularly 0.1%.
It is preferably from 5 to 5 parts. If the amount of the monomer unit exceeds 10 parts, the rubber component and the inorganic filler such as silica are agglomerated, so that the processability tends to decrease.

For conjugated diene rubbers such as NSBR and NSBR having a functional group, various monoolefinic monomers may be copolymerized, if necessary, in addition to monomers essential for the production of each rubber. Can be done. Examples of the monoolefin-based monomer include (meth) acrylates such as methyl acrylate and methyl methacrylate, (meth) acrylamides, and vinyl esters such as vinyl acetate. These monoolefin-based monomers can be used in a range that does not impair the required properties of the conjugated diene-based rubber. 20 mass% or less.

The weight average molecular weight of the conjugated diene rubber in terms of polystyrene determined by GPC (gel permeation chromatography) is 10%.
0000 or more, especially 100,000 to 200,000
It is preferably 0. This weight average molecular weight is 100
If it is less than 000, tan δ will increase and the wear resistance may decrease. On the other hand, when the weight average molecular weight is 200
If it exceeds 0000, workability tends to decrease, and in any case, it is not preferable. The weight average molecular weight can be adjusted by a chain transfer agent represented by an alkyl mercaptan generally used in radical polymerization.

NSBR and NSB having a functional group
The conjugated diene rubber such as R has a glass transition point of -60 to 0.
° C, and the difference between the extrapolation start temperature and the extrapolation end temperature of the glass transition is preferably 20 ° C or less. The glass transition point of NSBR and NSBR having a functional group varies depending on the composition ratio of the monomer used, but ASTM D341
-8 when measured by a differential scanning calorimeter (DSC) according to 8-82 (Reapproved 1988).
The temperature is 0 to 0C, and particularly preferably -50 to -10C. Further, the difference between the extrapolation start temperature and the extrapolation end temperature of the glass transition is 20 ° C. or less, and particularly preferably 18 ° C. or less. If this temperature difference exceeds 20 ° C., the wet skid resistance decreases and tan δ increases, which is not preferable.

Further, as a part of the rubber component, Japanese Patent Application
0-128144 and Japanese Patent Application No. 2000-128145, functional groups such as amino group, hydroxyl group and epoxy group having a particle size of 10 to 150 nm and a toluene insoluble content of 80% or more. Crosslinked rubber particles having the following can also be used. When the crosslinked rubber particles are used, the processability of the rubber composition can be greatly improved.

The conjugated diene rubber can be produced by subjecting monomers necessary for producing each rubber to radical polymerization in an aqueous medium. The polymerization method is not particularly limited, but usually an emulsion polymerization method is employed. This emulsion polymerization may be a general polymerization method, and each monomer is emulsified in an aqueous medium in the presence of an emulsifier, polymerization is started by a radical polymerization initiator, and when a predetermined polymerization conversion rate is reached. A method of adding a polymerization terminator to terminate the polymerization.

NSBR and NSB having a functional group
In R, the monomer is preferably added to the polymerization system in a divided or continuous manner before the start of the polymerization and during the reaction. When the entire amount of the monomer is introduced into the polymerization system and copolymerized before the start of polymerization, the difference between the onset temperature and the end temperature of the glass transition such as NSBR tends to be larger than 20 ° C., and This is not preferred because the composition distribution of NSBR and the like to be formed becomes wide.

As the emulsifier, an anionic surfactant,
Nonionic surfactants, cationic surfactants, amphoteric surfactants and the like can be mentioned. Further, a fluorine-based surfactant can also be used. One of these emulsifiers may be used alone, or two or more thereof may be used in combination.
Usually, anionic surfactants are frequently used, and for example, long-chain fatty acid salts having 10 or more carbon atoms, rosinates, and the like are used. Specific examples include potassium salts and sodium salts of capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, and stearic acid.

As the radical polymerization initiator, benzoyl peroxide, lauroyl peroxide, tert
-Butyl hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide, di-te
Organic peroxides such as rt-butyl peroxide and dicumyl peroxide can be used. Further, a diazo compound represented by azobisisobutyronitrile, an inorganic peroxide represented by potassium persulfate, and a redox catalyst represented by a combination of these peroxides and ferrous sulfate are used. You can also. These radical polymerization initiators may be used alone,
Two or more can be used in combination.

In the polymerization of the conjugated diene rubber, the monomers, emulsifiers, radical polymerization initiators, chain transfer agents, etc. may be charged all at once into a reaction vessel to initiate the polymerization, Add continuously or intermittently when the reaction is continued,
It may be added. Incidentally, in NSBR and the like, as described above,
It is not preferable to charge the whole amount of the monomers before the polymerization is started. This polymerization can be performed at 0 to 100 ° C. using a reactor from which oxygen has been removed, and is preferably performed at a polymerization temperature of 0 to 80 ° C. During the reaction, operating conditions such as temperature and stirring can be appropriately changed. The polymerization system may be a continuous system or a batch system.

Further, since a tendency to gel is observed when the polymerization conversion rate is increased, the polymerization conversion rate is preferably suppressed to 80% or less. Termination of the polymerization is performed by adding a polymerization terminator when a predetermined polymerization conversion rate is reached. Examples of the polymerization terminator include amine compounds such as hydroxylamine and diethylhydroxylamine, and quinone compounds such as hydroquinone.

After termination of the polymerization, unreacted monomers are removed from the resulting conjugated diene rubber latex by a method such as steam distillation, if necessary, and then salts such as sodium chloride, calcium chloride, potassium chloride, and the like. In some cases, hydrochloric acid, nitric acid, sulfuric acid or the like may be further added to solidify the conjugated diene rubber as crumb. After washing and dehydrating the crumb, the crumb is dried with a drier or the like to obtain a conjugated diene rubber.

The conjugated diene rubber can be used as a rubber which is blended with a rubber extender oil and oil-extended in advance. The extender oil for rubber is not particularly limited, and naphthenic, paraffinic and aromatic extender oils can be used, and aromatic extender oils are particularly preferred. The amount ratio of the rubber extender oil to be compounded in the conjugated diene rubber is 20 to 60 parts when the conjugated diene rubber is 100 parts,
In particular, it is preferably 20 to 50 parts. If the amount is less than 10 parts, the processability of the rubber composition is reduced, and
Exceeding 0 parts is not preferable because the extender oil is further added at the time of preparing the rubber composition, and the degree of freedom of the compounding amount when the extender oil is added decreases.

Examples of the above-mentioned "inorganic filler" include silica, aluminum hydroxide and the like. In particular, silica is frequently used. The silica is not particularly limited, and those generally used as a bright rubber reinforcing compounding agent for synthetic rubber can be used. The compounding amount of silica is preferably 20 to 150 parts, particularly preferably 20 to 100 parts when the rubber component is 100 parts. When the amount is less than 20 parts,
A sufficient reinforcing effect cannot be obtained, and the wet skid resistance and the like may be reduced. On the other hand, if 150 parts are blended, a sufficient reinforcing effect can be obtained, and it is not necessary to contain more than this amount.

The above-mentioned "compound" having at least one polymerizable unsaturated group and at least one functional group among an amino group, a hydroxyl group, an epoxy group and a carboxyl group includes the production of NSBR having a functional group. In the above, compounds used as monomers can be used, and in addition, the following various compounds can also be used.

[1] (a) exemplified as a monomer having at least one polymerizable unsaturated group and an amino group;
In addition to the salts of the compounds (b) and (c), [2] the compounds exemplified as monomers having at least one polymerizable unsaturated group and a hydroxyl group, (A) (poly) ethylene Di (meth) acrylates such as glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, and bisphenol A diglycidyl ether; (B) unsaturated fatty acid hydroxyalkyl esters of (poly) caprolactone,
(C) unsaturated fatty acid hydroxyalkyl esters of (poly) carbonate such as (poly) dimethyltrimethylene carbonate,

[3] In addition to the compounds exemplified as monomers having at least one polymerizable unsaturated group and a carboxyl group, unsaturated fatty acid esters of (poly) caprolactone and salts thereof, and specific salts thereof One type of compound may be used alone, or two or more types may be used in combination.
Also, at the time of compounding and vulcanization, the volatilization of the compound depending on the temperature
Alternatively, in order to prevent the rubber composition from foaming due to vaporization, it is preferable to use a compound having a molecular weight of 150 or more, especially 200 or more as described in claim 7.

The content of these specific compounds is 0.1 to 20 parts, especially 0.5 to 10 parts, when the rubber component is 100 parts. If the content is less than 0.1 part, the Mooney viscosity of the rubber composition is high, and the processability is poor, which is not preferable. On the other hand, if it exceeds 20 parts, the abrasion resistance and tensile strength of the vulcanized rubber may decrease, which is not preferable.

When the rubber composition of the present invention is put to practical use,
Usually, a reinforcing agent, a vulcanizing agent, a vulcanization accelerator and the like are blended. As the reinforcing agent, carbon black, carbon-silica dual-phase filler, and the like can be used. When silica and carbon black, which are inorganic fillers, are used in combination, the total amount is 10 to 150 parts, particularly 50 to 50 parts. 100
It is preferable to use a part. If the total amount is less than 10 parts, a sufficient reinforcing effect cannot be obtained, and the wet skid resistance and the like may decrease, which is not preferable. On the other hand, if the total amount is 150 parts, a sufficient reinforcing effect can be obtained, and it is not necessary to contain more than this amount. Further, the amount ratio of silica and carbon black is not particularly limited, but when silica is 100 parts, carbon black is 5 to 5 parts.
It is preferably 30 parts, particularly preferably 10 to 15 parts. When the amount ratio is within this range, a vulcanized rubber having excellent wet skid resistance, rebound resilience, tensile strength and the like can be obtained.

As a vulcanizing agent, sulfur is a typical one, but a sulfur-containing compound, a peroxide or the like can also be used. This vulcanizing agent is preferably used in an amount of usually 0.5 to 10 parts, especially 1 to 6 parts, when the rubber component is 100 parts. As the vulcanization accelerator, aldehyde ammonia-based, guanidine-based, thiourea-based, thiazole-based, dithiocarbamic acid-based and the like can be used.
It is preferable to mix 5 to 15 parts, particularly 1 to 10 parts.

In addition, clay, calcium carbonate, magnesium carbonate, and the like can be added in an appropriate amount as a filler, and a naphthene-based, paraffin-based, or aromatic-based extender oil for rubber can be added and added. Furthermore, zinc white, a vulcanization aid, an antioxidant, a processing aid and the like can be added in appropriate amounts.

A rubber product using the rubber composition of the present invention is:
It can be manufactured as follows. First, a rubber component, an inorganic filler such as silica, carbon black, a reinforcing agent such as a carbon-silica dual phase filler, a rubber extending oil, at least one polymerizable unsaturated group, an amino group, a hydroxyl group, A compound having at least one functional group of an epoxy group and a carboxyl group, and other compounding agents are kneaded at a temperature of 70 to 200 ° C. using a kneader such as a Banbury mixer. Thereafter, the kneaded material is cooled, and a vulcanizing agent such as sulfur, a vulcanization accelerator, and the like are further compounded using a Banbury mixer or a mixing roll, and molded into a predetermined shape. Then, 140-1
It is vulcanized at a temperature of 80 ° C. to obtain a required vulcanized rubber, that is, a rubber product. In addition, in the rubber composition of the present invention, since the silane coupling agent may not be used, the temperature at the time of kneading may be one.
It is not necessary to suppress the temperature to a low temperature of 50 to 160C or lower.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. [1] Method of measuring the amount of monomer binding The amount of monomer binding was measured by the following method. 1) Amount of styrene bond (% by mass): The rubber was dissolved in toluene and reprecipitated with methanol twice to purify the product, dried and vacuum dried, and a calibration curve was prepared by infrared absorption spectroscopy. I asked. 2) Amount of acrylonitrile bond (% by mass): The rubber was dissolved in toluene and reprecipitated with methanol twice to purify the product, dried in vacuum, subjected to elemental analysis, and calculated from the nitrogen content. .

3) Bonding amount (% by mass) of a monomer having an amino group; the rubber was dissolved in toluene and reprecipitated with methanol twice, purified, dried under vacuum, and dried.
It was measured by 0 MHz ¹ H-NMR. 4) Bonding amount (% by mass) of a monomer having a hydroxyl group; purification is performed by dissolving the rubber in toluene and reprecipitating with methanol twice, followed by vacuum drying, followed by drying.
Measured in MHz ¹ H-NMR.

5) Bonding amount (% by mass) of a monomer having an epoxy group: The rubber was dissolved in toluene and reprecipitated with methanol twice to purify the product, followed by vacuum drying.
Jay method [R. R. Jay; Anal. Chem. , 3
6,667 (1964)]. 6) Bonding amount (% by mass) of a monomer having a carboxyl group; the rubber was dissolved in toluene, reprecipitated with methanol twice, purified, dried under vacuum, and dissolved in chloroform. It was determined by neutralization titration.

[2] Measurement Methods of Physical Properties The weight average molecular weight of the conjugated diene rubber, the Mooney viscosity and processability of the oil-extended rubber and the rubber compound, and the physical properties of the vulcanized rubber were measured as follows. 1) Weight average molecular weight: determined by GPC (gel permeation chromatography) in terms of polystyrene. 2) Glass transition point; using a differential scanning calorimeter manufactured by Seiko Denshi Kogyo KK, ASTM D3418-82 (R
eapproved 1988).
The glass transition point is the extrapolation start temperature of the glass transition.

3) Mooney viscosity [(ML _{1 + 4} (100
° C)]; measured in accordance with JIS K 6300-1994 under the conditions of a measurement temperature of 100 ° C, a preheating of 1 minute, and a measurement of 4 minutes. 4) Processability: Evaluated by the winding property around the roll when the rubber composition was kneaded with the roll. The evaluation criteria are as follows. ◎: no lifting from the roll surface, small shrinkage after processing, extremely excellent. ；: Excellent without floating from the roll surface. Δ: winding, but floating, inferior
×: hardly wrapped, very poor

5) Tensile properties: JIS K6301-1
Measurement No. 25 using No. 3 type test piece
The elongation at break (%) and the tensile strength (MPa) were measured at a temperature of 500 ° C. and a tensile speed of 500 mm / min. 6) Rebound resilience; 50 using Dunlop trypsometer
Measured in ° C. 7) tan δ; using a dynamic analyzer (RDA) manufactured by Rheometrics, USA, with a dynamic distortion of 3% and a frequency of 10H
The measurement was performed under the conditions of z and measurement temperature of 50 ° C. The smaller the numerical value, the better the rolling resistance is small. 8) Lambourn abrasion index: The abrasion amount at a slip ratio of 60% was calculated using a Lambourn abrasion tester. The measurement temperature is 50 ° C. The larger the index, the better the wear resistance.

[3] Production of conjugated diene rubber Production Example 1 [Conjugated diene rubber (a)] In a polymerization vessel, 200 parts of water, 4.5 parts of rosin acid soap, 65 parts of butadiene, 26 parts of styrene, acrylonitrile 5
And 1 part of diethylaminoethyl methacrylate. Thereafter, the temperature of the polymerization vessel was set to 5 ° C., and 0.03 part of p-menthane hydroperoxide, 0.02 part of sodium ethylenediaminetetraacetate, and 0.01% of ferrous sulfate heptahydrate were used as radical polymerization initiators. And 0.03 part of sodium formaldehyde sulfoxylate were added to initiate polymerization. When the polymerization conversion reached 30%, 3 parts of acrylonitrile was added and the polymerization conversion was 6%.
When 0% was reached, diethylhydroxylamine was added to terminate the polymerization.

Next, unreacted monomers were recovered by steam stripping to obtain a conjugated diene rubber latex. Bonding amount of each monomer constituting the conjugated diene rubber contained in this latex, bonding amount of diethylaminoethyl methacrylate, weight average molecular weight, glass transition point, and extrapolation start temperature and extrapolation end temperature of glass transition Is shown in Table 1 below.

On the other hand, an emulsion containing an aroma oil (trade name “Fukor Aromax # 3”, manufactured by Fujikosan Co., Ltd.) was added to a conjugated diene rubber latex based on 100 parts of solids contained in the latex. 3 aroma oils
It was blended so as to be 7.5 parts, and this was coagulated with sulfuric acid and sodium chloride to obtain crumbs. Thereafter, the crumb was dried with a hot air drier to obtain a conjugated diene rubber (a) oil-extended with aroma oil. The Mooney viscosity of this oil-extended conjugated diene rubber is shown in Table 1 below.

Production Examples 2 to 4 [Conjugated diene rubber (b),
(C) and (d)] Instead of using diethylaminoethyl methacrylate in Production Example 1, 2-hydroxyethyl methacrylate (Production Example 2), glycidyl methacrylate (Production Example 3), or methacrylic acid (Production Example 4) was used. A conjugated diene rubber latex was obtained by the same operation and procedure as in Production Example 1.
The bonding amount of each monomer constituting the conjugated diene rubber contained in these latexes, the weight average molecular weight of the rubber,
The glass transition point and the difference between the extrapolation start temperature and the extrapolation end temperature of the glass transition were measured in the same manner as in Production Example 1.
In addition, the amounts of 2-hydroxyethyl methacrylate, glycidyl methacrylate and methacrylic acid combined were measured by the method described above. The results are also shown in Table 1.

Further, each of the conjugated diene rubber latexes was blended with an emulsion containing an aroma oil in the same manner as in Production Example 1, and this was crumbed, dried, and conjugated diene oil-extended with the aroma oil. The system rubbers (b), (c) and (d) were obtained.

Production Example 5 [Conjugated Diene Rubber (e)] A polymerization vessel was charged with 200 parts of water, 4.5 parts of a rosin acid soap, 58 parts of butadiene, and 42 parts of styrene. Thereafter, the temperature of the polymerization vessel was set at 5 ° C., and the same amount of the radical polymerization initiator used in Production Example 1 as in Production Example 1 was added to initiate polymerization, and the polymerization conversion reached 60%. At that time, diethylhydroxylamine was added to terminate the polymerization. Next, a conjugated diene copolymer latex was obtained in the same manner as in Production Example 1. The amount of each monomer constituting the conjugated diene rubber contained in this latex,
The weight average molecular weight of the rubber, the glass transition point, and the difference between the extrapolation start temperature and the extrapolation end temperature of the glass transition were measured in the same manner as in Production Example 1. The results are also shown in Table 1.

An emulsion containing an aroma oil was added to the conjugated diene-based rubber latex in the same manner as in Production Example 1. The resulting emulsion was crumbed, dried, and oil-extended with the aroma oil. Rubber (e) was obtained.

[0059]

[Table 1]

Production Example 6 [Conjugated diene rubber (f)] In a polymerization vessel, 200 parts of water, 4.5 parts of rosin acid soap, 59 parts of butadiene, 35 parts of acrylonitrile, 5 parts of 2-hydroxyethyl methacrylate, and 5 parts of divinyl 1 part of benzene was charged. Thereafter, the temperature of the polymerization vessel was set at 15 ° C., the same amount of the radical polymerization initiator used in Production Example 1 as in Production Example 1 was added, and polymerization was started.
The reaction was carried out for a time to obtain a latex containing crosslinked rubber particles. The polymerization conversion was about 100%.

Next, an emulsion containing 10 parts by weight of a crosslinked rubber particle latex corresponding to a solid content, 90 parts by weight of a conjugated diene rubber latex in Production Example 2, and an aroma oil-containing emulsion was mixed with the solid content contained in the latex. Aroma oil was mixed to 100 parts with 37.5 parts and coagulated with sulfuric acid and sodium chloride to obtain crumb. Thereafter, the crumb was dried with a hot air drier to obtain a conjugated diene rubber (f) oil-extended with aroma oil. The Mooney viscosity of this oil-extended conjugated diene rubber was 49.

[4] Preparation of rubber composition and vulcanized rubber, evaluation of physical properties Examples 1 to 5 and Comparative Examples 1 to 3 Using conjugated diene rubbers (a) to (f), Tables 2 and 3 After kneading with a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) to obtain the rubber compositions of Examples 1 to 5 and Comparative Examples 1 to 3, the mixture was vulcanized at 160 ° C. for 20 minutes by a vulcanizing press, A vulcanized rubber was obtained. The processability and Mooney viscosity of the rubber compositions of Examples 1 to 5 and Comparative Examples 1 to 3 and the physical properties of the vulcanized rubber were evaluated. Tables 2 and 3 show the results.
It is described together.

[0063]

[Table 2]

[0064]

[Table 3]

The following ingredients were used in the above formulation. Silica; manufactured by Nippon Silica Co., Ltd.
Q "Carbon black; Mitsubishi Chemical Corporation, trade name" Diablack N220 "Silane coupling agent; Degussa Corporation, trade name" Si
69 "Antioxidant; Ouchi Shinko Chemical Co., Ltd., trade name" Nocrack 810NA "Vulcanization accelerator (1); Ouchi Shinko Chemical Co., Ltd., trade name" Noxeller CZ "Vulcanization accelerator (2 ); Manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trade name "Noxeller D"

According to the results shown in Table 2, in the rubber compositions of Examples 1 to 5 using the conjugated diene rubbers (a) to (d) and (f), no silane coupling agent was used. Nevertheless, it can be seen that all are excellent in workability. In addition, since tan δ at 50 ° C. is small, rolling resistance can be reduced when used for a tire. Further, it can be seen that the Lambourn abrasion index is sufficiently large, and a vulcanized rubber excellent in abrasion resistance is obtained. Further, in Example 5 using the conjugated diene rubber (f) containing crosslinked rubber particles as a part of the rubber component, shrinkage of the rubber compound was suppressed, workability was particularly greatly improved, and vulcanization was performed. It can be seen that the rubber has sufficient abrasion resistance and tensile strength.

On the other hand, according to the results shown in Table 3, the conjugated diene rubber (a) was used and silica was blended, but in Comparative Example 1 in which a compound having a specific functional group was not blended, Although there is no particular problem, Mooney viscosity is high,
It can be seen that the workability is poor. In Comparative Example 2 where conjugated diene rubber (e) was used and silica was compounded, but a compound having a specific functional group was not compounded and a silane coupling agent was compounded, Although the properties are good, tan δ is large, and when used in a tire, the rolling resistance increases. Furthermore, it can be seen that in Comparative Example 3 having the same composition as Comparative Example 2 except that the silane coupling agent was not blended, the processability was poor and the wear resistance of the vulcanized rubber was greatly reduced.

[0068]

According to the present invention, a rubber composition having good processability can be obtained even when an inorganic filler such as silica is blended as a reinforcing agent. Further, the vulcanized rubber comprising this rubber composition has low rolling resistance and excellent wet skid resistance and wear resistance, and is particularly useful for tires.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 9/00 (C08L 9/00 91:00) 91:00) (72) Inventor Tadaki Toshihiro 2-11-24 Tsukiji 2-chome, Chuo-ku, Tokyo FSR in JSR Inc. BA04Q BA08S BA27S CA06 DA01 JA29

Claims (7)

[Claims] [1] A rubber component containing 30% by mass or more of a conjugated diene rubber, [2] an inorganic filler, and [3] at least one polymerizable unsaturated group, an amino group, a hydroxyl group, A rubber composition containing a compound having at least one functional group of an epoxy group and a carboxyl group, wherein the inorganic filler is 20 to 150 parts by mass when the rubber component is 100 parts by mass. And the compound is 0.1 to 20 parts by mass. 2. The above-mentioned conjugated diene rubber has, as repeating units, (1) 1 to 30% by mass of an olefinically unsaturated nitrile monomer unit, and (2) 1 to 4 units of an aromatic vinyl monomer unit.
0 to 50% by mass, and (3) 2 units of the conjugated diene monomer unit.
0 to 89% by mass [The total amount of (1), (2) and (3) is 100% by mass. The rubber composition according to claim 1, further comprising: 3. The conjugated diene rubber according to claim 1, wherein the repeating unit is (4) at least one polymerizable unsaturated group and at least one functional group of an amino group, a hydroxyl group, an epoxy group and a carboxyl group. 10 parts by mass or less [The total amount of (1), (2) and (3) above is 100 parts by mass. The rubber composition according to claim 2, comprising: 4. The rubber composition according to claim 1, wherein the weight average molecular weight of the conjugated diene rubber is 100,000 or more. 5. The method according to claim 1, wherein the conjugated diene-based rubber is oil-extended with 20 to 60 parts by weight of an extending oil when the conjugated diene-based rubber is 100 parts by weight. Or the rubber composition according to item 1. 6. The method of claim 1, wherein said inorganic filler is silica.
The rubber composition according to any one of Items 1 to 5, wherein 7. The rubber composition according to claim 1, wherein the compound has a molecular weight of 200 or more.