JPWO2017038724A1 - Coated polymer particles, resin modifier, rubber composition and tire - Google Patents

Abstract

Coated polymer particles having particles (x) and an outermost coating film covering at least a part of the particles (x), wherein the particles (x) comprise a monomer unit derived from farnesene (A) A coated polymer particle containing the polymer (B), and a resin modifier, a rubber composition, and a tire using the coated polymer particle.

Description

  The present invention relates to coated polymer particles, a resin modifier using the same, a rubber composition, and a tire. More specifically, the present invention relates to coated polymer particles useful as a resin modifier for tire applications, for example.

  Polymer particles containing a conjugated diene polymer are known as resin modifiers. For example, in tire applications, polymer particles made of styrene / butadiene rubber gel having a swelling index in toluene in a specific range and a particle size in a specific range are mixed with rubber to improve wear resistance and rolling. It is known that the resistance performance can be improved (see Patent Document 1). However, since the polymer particles using butadiene have a high viscosity, there is a problem that the processability of the rubber is lowered by the addition of the polymer particles.

JP 2010-095724 A

  The present invention has been made in view of the above situation, and in tire applications, while maintaining excellent rolling resistance performance, while suppressing deterioration of rubber processability, coated polymer particles excellent in wear resistance, and It aims at providing the resin modifier, rubber composition, and tire using this.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that the polymer particles are coated polymer particles having particles and an outermost coating covering at least a part of the particles, and the particles are derived from farnesene. The present invention has been completed by finding that the above-mentioned problems can be solved by coated polymer particles, which are polymers containing monomer units.

That is, the present invention relates to the following [1] to [13].
[1] Coated polymer particles having particles (x) and an outermost coating covering at least a part of the particles (x),
The particle (x) contains a polymer (A) containing a monomer unit derived from farnesene,
Coated polymer particles, wherein the outermost coating contains a polymer (B).
[2] In the above [1], the polymer (A) is a copolymer comprising a monomer unit derived from farnesene and a monomer unit derived from another radical polymerizable monomer (a). Coated polymer particles as described.
[3] The content of the monomer unit derived from the radical polymerizable monomer (a) in the polymer (A) is 5 to 95% by mass with respect to the total mass of the polymer (A). Coated polymer particles according to 2].
[4] The radical polymerizable monomer (a) is a conjugated diene other than farnesene, an aromatic vinyl compound, (meth) acrylic acid and its salt, (meth) acrylic acid ester, and (N-alkyl) (meth). The coated polymer particle according to the above [2] or [3], which is at least one selected from the group consisting of acrylamide.
[5] The coated polymer particle according to any one of [1] to [4], wherein the polymer (B) is a polymer containing a monomer unit derived from a conjugated diene.
[6] The polymer (B) is a copolymer including a monomer unit derived from a conjugated diene and a monomer unit derived from another radical polymerizable monomer (b), and the radical polymerizable property. The monomer (b) is at least one selected from the group consisting of aromatic vinyl compounds, (meth) acrylic acid and salts thereof, (meth) acrylic acid esters, and (N-alkyl) (meth) acrylamides. The coated polymer particle according to any one of [1] to [5] above.
[7] The content of the monomer unit derived from the radical polymerizable monomer (b) in the polymer (B) is 1 to 80% by mass with respect to the total mass of the polymer (B). Coated polymer particles according to 6].
[8] The radical polymerizable monomer (b) is (meth) acrylic acid and a salt thereof, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid N, N′— The coating according to [6] or [7] above, which is at least one selected from the group consisting of dialkylaminoalkyl esters, trialkoxysilylalkyl esters of (meth) acrylic acid, and (N-alkyl) (meth) acrylamides Polymer particles.
[9] Any of [1] to [8] above, wherein the mass ratio [particle (x) / outermost coating] of the particles (x) to the outermost coating is in the range of 95/5 to 50/50. Coated polymer particles described in 1.
[10] Any of [1] to [9] above, wherein the particle (x) is a particle having a coating composed of at least one layer covering at least a part of the particle (x ′) and the particle (x ′). Coated polymer particles described in 1.
[11] A resin modifier containing the coated polymer particles according to any one of [1] to [10].
[12] A rubber composition containing the rubber component (X) including the coated polymer particles according to any one of the above [1] to [10] and a filler (Y), wherein the total amount of the rubber component (X) The rubber composition in which the content of the coated polymer particles is 1 to 50% by mass and the filler (Y) is contained in an amount of 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component (X).
[13] A tire using at least a part of the rubber composition according to [12].
Hereinafter, the “polymer (A) containing a monomer unit derived from farnesene” is also simply referred to as “polymer (A)”, and the “radically polymerizable monomer (a)” is simply referred to as “monomer (a ) ", And" radically polymerizable monomer (b) "is also simply referred to as" monomer (b) ". Hereinafter, “a monomer unit derived from farnesene” is also simply referred to as “farnesene unit”, and “a monomer unit derived from conjugated diene” is also simply referred to as “conjugated diene unit”.
In the present specification, “(meth) acryl” means one or two selected from “methacryl” and “acryl”, and “(N-alkyl) (meth) acrylamide” It means one or more selected from “(meth) acrylamide” and “N-alkyl (meth) acrylamide”.

  According to the present invention, in a tire application, coated polymer particles that suppress deterioration in workability of rubber and have excellent wear resistance while maintaining excellent rolling resistance performance, and a resin modifier and rubber using the same Compositions and tires can be provided.

[Coated polymer particles]
The coated polymer particle of the present invention is a coated polymer particle having a particle (x) and an outermost coating film covering at least a part of the particle (x), wherein the particle (x) is a heavy polymer containing a farnesene unit. A coalescence (A) is contained and this outermost film contains a polymer (B).
In the coated polymer particle of the present invention, the particle (x) is a portion of the inner layer in the coated polymer particle, and the outermost coating is a portion of the outermost layer. In the present invention, “coating” refers to a state in which the outermost coating covers at least a part of the surface of the particle (x), and preferably covers the entire surface.

<Particle (x)>
The particles (x) in the present invention contain a polymer (A) containing farnesene units. The polymer (A) is formed by polymerization of a monomer containing farnesene. When the polymer (A) constituting the particle (x) contains a farnesene unit, it is possible to suppress an increase in viscosity due to the addition of the coated polymer particle, improve workability, and improve wear resistance. it can.
Such farnesene may be α-farnesene, may be β-farnesene represented by the following formula (I), and may include α-farnesene and β-farnesene. From the viewpoint of sex, it is preferable to include β-farnesene.
From the viewpoint of ease of production, the content of the monomer unit derived from β-farnesene is preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass, that is, farnesene units. It is more preferable that all of the above are monomer units derived from β-farnesene.
Moreover, it is preferable that the farnesene unit contained in a polymer (A) is bridge | crosslinked. When the polymer (A) is crosslinked, the low molecular weight polymer component that causes a decrease in wear resistance is reduced. The smaller the toluene swelling index described below, the higher the degree of crosslinking.
The content of the farnesene unit in the polymer (A) is preferably in the range of 5 to 100% by mass, preferably 5 to 95% by mass with respect to the total mass of the polymer (A), from the viewpoints of workability and wear resistance. Is more preferable, the range of 20 to 95 mass% is more preferable, the range of 30 to 90 mass% is still more preferable, and the range of 40 to 80 mass% is still more preferable.

The polymer (A) of the present invention may be a copolymer containing a farnesene unit and a monomer unit derived from a radical polymerizable monomer (a) other than farnesene.
Monomers (a) include conjugated dienes other than farnesene such as butadiene and isoprene; aromatic vinyl compounds such as styrene, α-methylstyrene and tert-butylstyrene; (meth) acrylic acid and salts thereof; (meth) (Meth) acrylic acid esters such as methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, N- (N-alkyl) (meth) acrylamides such as ethyl (meth) acrylamide; nitriles such as (meth) acrylonitrile; vinyl esters such as vinyl acetate, vinyl n-propionate, vinyl butyrate and vinyl pivalate; maleic anhydride, anhydrous Unsaturated dicarboxylic anhydrides such as itaconic acid; ethene, propene, -Monoolefins such as butene and isobutene; Halogenated ethylene such as vinyl bromide, vinylidene bromide, vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; Allyl compounds such as allyl acetate and allyl chloride; Maleic acid and Itacone And unsaturated dicarboxylic acids such as acids and salts thereof; unsaturated dicarboxylic acid esters such as maleic acid esters and itaconic acid esters; vinylsilyl compounds such as vinyltrimethoxysilane and vinyltriethoxysilane; and the like. Among these, from the viewpoint of copolymerization with farnesene, conjugated dienes other than farnesene, aromatic vinyl compounds, (meth) acrylic acid and salts thereof, (meth) acrylic acid esters, and (N-alkyl) (meth) At least one selected from the group consisting of acrylamide is preferable, and from the viewpoint of improving rolling resistance performance, conjugated dienes other than farnesene are more preferable, butadiene is more preferable, and workability, wear resistance, and rolling resistance performance are improved. From the viewpoint, an aromatic vinyl compound is more preferable, and styrene is more preferable. A monomer (a) may be used individually by 1 type, or may use 2 or more types together.
The content of the monomer unit derived from the monomer (a) in the polymer (A) is preferably in the range of 0 to 95% by mass, and 5 to 95% by mass with respect to the total mass of the polymer (A). Is more preferable, the range of 5-80 mass% is further more preferable, the range of 10-70 mass% is further more preferable, and 20-60 mass% is still more preferable.

  When the polymer (A) is a copolymer containing a farnesene unit and a monomer unit derived from the monomer (a), the farnesene unit and the monomer unit derived from the monomer (a) The mass ratio [farnesene unit / monomer unit derived from monomer (a)] is preferably 95/5 to 30/70, and preferably 90/10 to 40 from the viewpoints of workability, wear resistance and rolling resistance performance. / 60 is more preferable, 80/20 to 50/50 is more preferable, and 70/30 to 60/40 is still more preferable.

The particles (x) may contain a plurality of types of polymers (A) having different monomer compositions, and the particles (x ′) and at least one layer covering at least a part of the particles (x ′). The particle | grains which consist of several layers which have the film which becomes may be sufficient.
The content of the particles (x ′) in the particles (x) is preferably in the range of 1 to 50% by mass, more preferably in the range of 7 to 30% by mass, and from 10 to 20% by mass from the viewpoint of ease of production. A range is more preferred.

From the viewpoint of workability, wear resistance and rolling resistance performance, the particles (x) are composed of another polymer (A ′) containing a monomer unit having a composition different from that of the polymer (A) (hereinafter simply referred to as “polymer”). (A ′) ”) and a coating containing the polymer (A) covering at least a part of the particles (x ′) preferable.
Monomers that can form such other polymers (A ′) include conjugated dienes such as butadiene, isoprene, and farnesene; aromatic vinyl compounds such as styrene, α-methylstyrene, and tert-butylstyrene; (meth) acrylic Acids and salts thereof; (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate; (meth) acrylamide, N- (N-alkyl) (meth) acrylamides such as methyl (meth) acrylamide and N-ethyl (meth) acrylamide; nitriles such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether and isobutyl vinyl ether; Vinyl acetate, n-propio Vinyl esters such as vinyl acid, vinyl butyrate and vinyl pivalate; unsaturated dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; monoolefins such as ethene, propene, n-butene and isobutene; vinyl bromide and bromide Halogenated ethylene such as vinylidene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids such as maleic acid and itaconic acid and salts thereof; And unsaturated dicarboxylic acid esters such as itaconic acid esters; vinylsilyl compounds such as vinyltrimethoxysilane and vinyltriethoxysilane;

Among these, from the viewpoint of workability, wear resistance and rolling resistance performance, at least one selected from the group consisting of conjugated dienes and aromatic vinyl compounds is preferable, conjugated dienes are more preferable, and farnesene is more preferable.
The polymer (A ′) may be a copolymer containing a monomer unit derived from farnesene and a monomer unit derived from another radical polymerizable monomer (a ′). From the viewpoint of copolymerization with farnesene, the polymerizable monomer (a ′) is a conjugated diene other than farnesene, an aromatic vinyl compound, (meth) acrylic acid and its salt, (meth) acrylic acid ester, and ( N-alkyl) (meth) acrylamide is preferably at least one selected from the group consisting of (meth) acrylamides, and from the viewpoint of workability, wear resistance and rolling resistance performance, selected from the group consisting of conjugated dienes other than farnesene and aromatic vinyl compounds. At least one selected from the group consisting of butadiene and styrene is more preferable. These may be used alone or in combination of two or more.

  The content of the particles (x) in the coated polymer particles of the present invention is preferably in the range of 10 to 99.9% by mass, and 30 to 99.9% by mass with respect to the total mass of the coated polymer particles. Is more preferable, it is still more preferable that it is the range of 40-95 mass%, and it is still more preferable that it is the range of 60-95 mass%.

The content of the polymer (A) in the particles (x) is preferably in the range of 60 to 100% by mass, more preferably in the range of 80 to 100% by mass, from the viewpoints of workability and wear resistance. A range of mass% is more preferred. When the particles (x) include a plurality of types of polymers (A) having different monomer compositions, the content of the polymer (A) is the total amount of the plurality of types of polymers (A). .
The content of the polymer (A ′) in the particles (x ′) is preferably in the range of 60 to 100% by mass, more preferably in the range of 80 to 100% by mass, from the viewpoints of workability and wear resistance. The range of ˜100% by mass is more preferable.

<Outermost coating>
The outermost coating in the present invention contains the polymer (B).
Monomers that can form the polymer (B) of the present invention include conjugated dienes such as butadiene, isoprene, and farnesene; aromatic vinyl compounds such as styrene, α-methylstyrene, and tert-butylstyrene; (meth) acrylic acid And salts thereof; (meth) acrylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and hydroxyalkyl (meth) acrylate (Meth) acrylic acid esters such as esters, (meth) acrylic acid glycidyl esters, (meth) acrylic acid N, N′-dialkylaminoalkyl esters, (meth) acrylic acid trialkoxysilylalkyl esters; (meth) acrylamides, N -Methyl (meth) acrylamide, N-ethyl (meta (N-alkyl) (meth) acrylamides such as acrylamide; nitriles such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether; vinyl acetate, vinyl n-propionate, vinyl butyrate, Vinyl esters such as vinyl pivalate; unsaturated dicarboxylic anhydrides such as maleic anhydride and itaconic anhydride; monoolefins such as ethene, propene, n-butene and isobutene; vinyl bromide, vinylidene bromide, vinyl chloride, chloride Halogenated ethylene such as vinylidene, vinyl fluoride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids such as maleic acid and itaconic acid and salts thereof; maleic acid esters and itaconic acid esters The sum dicarboxylic acid esters; vinyl triethoxysilane, vinyl silyl compounds such as vinyltrimethoxysilane; and the like.

Among these, from the viewpoint of workability, wear resistance and rolling resistance performance, conjugated dienes, aromatic vinyl compounds, (meth) acrylic acid and salts thereof, (meth) acrylic acid esters, and (N-alkyl) (meta) ) At least one selected from the group consisting of acrylamide is preferable, and at least one selected from the group consisting of conjugated dienes, aromatic vinyl compounds, (meth) acrylic acid and salts thereof, and (meth) acrylic acid esters is more preferable. .
The conjugated diene is preferably at least one selected from the group consisting of farnesene, butadiene and isoprene, more preferably at least one selected from the group consisting of farnesene and butadiene.
The aromatic vinyl compound is preferably at least one selected from the group consisting of styrene and α-methylstyrene, and more preferably styrene.
Examples of the (meth) acrylic acid ester include (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid N, N′-dialkylaminoalkyl ester, and (meth) acrylic acid trialkoxy At least one selected from the group consisting of silylalkyl esters is preferred, at least one selected from the group consisting of (meth) acrylic acid hydroxyalkyl esters and (meth) acrylic acid glycidyl esters is more preferred, 2-hydroxybutyl methacrylate and More preferred is at least one selected from the group consisting of glycidyl methacrylate.
These may be used alone or in combination of two or more.
The farnesene used for the polymer (B) may be α-farnesene as in the case of the polymer (A), may be β-farnesene represented by the formula (I), and α- Although it may contain farnesene and β-farnesene, it is preferable to contain β-farnesene from the viewpoint of ease of production.
In addition, when a polymer (B) contains a farnesene unit, it is preferable that a polymer composition is not the same as a polymer (A) and a polymer (B).

The polymer (B) of the present invention preferably contains a conjugated diene unit from the viewpoints of workability, wear resistance and rolling resistance performance. Such conjugated diene units are formed by polymerization of the conjugated diene described above. The conjugated diene is preferably at least one selected from the group consisting of farnesene, butadiene and isoprene, from the viewpoint of wear resistance and rolling resistance performance, more preferably a combination of farnesene and another conjugated diene, and farnesene and butadiene or The combined use with isoprene is more preferable, and the combined use of farnesene and butadiene is more preferable.
The polymer (B) may be a copolymer containing a conjugated diene unit and a monomer unit derived from another radical polymerizable monomer (b). Monomer (b) is an aromatic vinyl compound, (meth) acrylic acid and its salt, (meth) acrylic acid ester, and (N-alkyl) (from the viewpoint of workability, wear resistance and rolling resistance performance. At least one selected from the group consisting of (meth) acrylamides is preferable, and at least one selected from the group consisting of aromatic vinyl compounds, (meth) acrylic acid and salts thereof, and (meth) acrylic acid esters is more preferable.

The content of the conjugated diene unit in the polymer (B) is preferably in the range of 20 to 100% by mass and preferably in the range of 20 to 99% by mass with respect to the total mass of the polymer (B). More preferably, it is in the range of 40 to 99% by mass, and more preferably in the range of 60 to 98% by mass.
The content of the monomer unit derived from the monomer (b) in the polymer (B) is preferably in the range of 0 to 80% by mass with respect to the total mass of the polymer (B). The range is more preferably 80% by mass, still more preferably 1 to 60% by mass, and even more preferably 2 to 40% by mass.
When farnesene and other conjugated dienes are used in combination as monomers that form conjugated diene units, the mass ratio of farnesene to other conjugated dienes [farnesene / other conjugated dienes] is the workability and wear resistance. In view of the above, 5/95 to 95/5 are preferable, 30/70 to 70/30 are more preferable, and 40/60 to 60/40 are even more preferable.

  When the polymer (B) is a copolymer containing a conjugated diene unit and a monomer unit derived from the monomer (b), the monomer unit derived from the conjugated diene unit and the monomer (b) The mass ratio of [conjugated diene unit / monomer unit derived from monomer (b)] is preferably 98/2 to 50/50 from the viewpoint of processability, wear resistance and rolling resistance performance, and 95 / 5-60 / 40 is more preferable, and 95 / 5-70 / 30 is further more preferable.

The polymer (B) forming the outermost coating preferably has a reactive functional group from the viewpoint of improving the wear resistance and rolling resistance performance. When the coated polymer particles of the present invention are used as a resin modifier or when blended in a rubber composition, the reactive functional group of the polymer (B) reacts with a filler component contained in the resin or rubber composition. By improving the dispersibility of the filler, the effect of improving the wear resistance and rolling resistance performance can be obtained.
Examples of such reactive functional groups include hydroxyl groups, carboxy groups, epoxy groups, amino groups, N-alkylamino groups, trialkoxysilyl groups, and the like.
As a method for introducing the functional group into the polymer (B), it is preferable to use a conjugated diene and the monomer (b) having the functional group in combination as a copolymer.
As the monomer (b), from the viewpoint of improving rolling resistance performance, (meth) acrylic acid and its salt; (meth) such as 2-hydroxyethyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate Hydroxyalkyl esters of acrylic acid; (meth) acrylic acid glycidyl esters such as glycidyl (meth) acrylate; (meth) such as N, N′-dimethylaminoethyl (meth) acrylate and N, N′-diethylaminoethyl (meth) acrylate N, N'-dialkylaminoalkyl acrylates; (meth) acrylic acid trialkoxylates such as (meth) acrylic acid triethoxysilylpropyl, (meth) acrylic acid trimethoxysilylpropyl, (meth) acrylic acid methyldimethoxysilylpropyl Silyl alkyl esters, side by side At least one selected from the group consisting of (N-alkyl) (meth) acrylamides such as (meth) acrylamide and N-methyl (meth) acrylamide is preferred. From the viewpoint of ease of production of the copolymer, (meth) Acrylic acid and its salt, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid N, N′-dialkylaminoalkyl ester, and (N-alkyl) (meth) acrylamide At least one selected from the group is more preferable, at least one selected from the group consisting of (meth) acrylic acid and salts thereof, (meth) acrylic acid hydroxyalkyl ester and (meth) acrylic acid glycidyl ester is more preferable, Acid, glycidyl methacrylate and 2- At least one selected from the group consisting of mud carboxybutyl methacrylate is more preferred more.
These may be used alone or in combination of two or more.

The content of the outermost coating in the coated polymer particles of the present invention is preferably in the range of 0.1 to 90% by mass, based on the total mass of the coated polymer particles, and is 0.1 to 70% by mass. The range is more preferable, the range of 5 to 60% by mass is further preferable, and the range of 5 to 40% by mass is still more preferable.
The content of the polymer (B) in the outermost coating is preferably in the range of 60 to 100% by mass, more preferably in the range of 80 to 100% by mass, from the viewpoints of workability, wear resistance, and rolling resistance performance. The range of ˜100% by mass is more preferable.

  The mass ratio of the particles (x) to the outermost coating [particles (x) / outermost coating] is in the range of 95/5 to 50/50 from the viewpoint of the balance of workability, wear resistance and rolling resistance performance. Preferably, it is in the range of 90/10 to 60/40, more preferably in the range of 80/20 to 65/35.

When the coated polymer particle of the present invention is used as a resin modifier for tire applications, it is preferably crosslinked from the viewpoint of improving wear resistance. Regarding the degree of crosslinking of the coated polymer particles of the present invention, the toluene swelling index of the coated polymer particles can be used as an index. From the above viewpoint, the toluene swelling index is preferably from 1 to 80, more preferably from 1 to 60, further preferably from 6 to 40, and even more preferably from 6 to 25.
The toluene swelling index is determined by the mass ratio (α) of the toluene swollen mass obtained by swelling the coated polymer particles with toluene and the mass (β) after drying of the toluene swollen mass by the method described in Examples. / Β) can be obtained by measuring. The lower the toluene swelling index, the higher the degree of crosslinking.

  When used as a resin modifier for tire applications, the average particle size of the coated polymer particles of the present invention is preferably 10 to 200 nm, more preferably 20 to 100 nm, from the viewpoint of the balance between easy dispersibility and the modification effect. 30-80 nm is more preferable. The average particle diameter is measured by embedding the coated polymer particles in a methacrylic resin, staining with osmium tetroxide, and observing the particle image with a transmission electron microscope by the method described in Examples.

  In the present invention, the ratio of the average particle diameter of the particles (x) to the average thickness of the outermost coating [the average particle diameter of the particles (x) / the average thickness of the outermost coating] represents the workability, wear resistance, and rolling resistance performance. From the viewpoint, a range of 1 to 1,000 is preferable, a range of 2 to 500 is more preferable, a range of 3 to 100 is more preferable, a range of 4 to 50 is still more preferable, and a range of 5 to 30 is still more preferable. The range of 7 to 20 is even more preferable. In addition, the average particle diameter of particle | grains (x) and the average thickness of outermost film are measured by the method as described in an Example.

The coated polymer particle of the present invention is an anti-aging agent, an antioxidant, a wax, a lubricant as necessary for the purpose of improving the weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the present invention are not impaired. , Light stabilizers, scorch prevention agents, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, You may contain 1 type (s) or 2 or more types of additives, such as an antifungal agent and a fragrance | flavor.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, hydroquinone compounds, and the like. Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenolic compounds, sulfur compounds, and phosphorus compounds.

(Method for producing coated polymer particles)
The coated polymer particles of the present invention can be produced, for example, by emulsion polymerization, and are preferably obtained by a production method having the following steps 1 and 2.
Step 1: Step of obtaining emulsion of particles (x) containing polymer (A) by emulsion polymerization of water-containing monomer forming polymer (A) in water Step 2: Obtained in Step 1 A monomer for forming the polymer (B) is further added to the obtained emulsion and emulsion polymerization is carried out in water to obtain an emulsion of coated polymer particles having an outermost film containing the polymer (B). The process of obtaining

Film (x) comprising polymer (A), particles (x ′) containing polymer (A ′), and film containing polymer (A) covering at least part of the particles (x ′) In the case of producing coated polymer particles that are particles having the following, it is preferable to have the following steps 1-1 and 1-2 as step 1 before step 2.
Step 1-1: A step of emulsion-polymerizing the monomer forming the polymer (A ′) in water to obtain an emulsion of particles (x ′) containing the polymer (A ′) Step 1-2: Particles having a coating film containing the polymer (A) by further adding a monomer containing farnesene that forms the polymer (A) to the emulsion obtained in step 1-1 and emulsion polymerization in water. Step of Obtaining Emulsified Liquid (x) When the coating film covering the particles (x ′) is composed of a plurality of layers, it can be produced by repeating the above step 1-2.

  The amount of water used in the emulsion polymerization is 100 masses of the sum of the monomer forming the polymer (A) and the monomer forming the polymer (B) from the viewpoint of the viscosity and stability of the emulsion. The amount is preferably in the range of 50 to 1,500 parts by mass, more preferably in the range of 80 to 1,000 parts by mass, and still more preferably in the range of 100 to 800 parts by mass.

In the emulsion polymerization, an emulsifier and a polymerization initiator are usually used.
The emulsifier used in the emulsion polymerization is preferably an anionic emulsifier such as a fatty acid salt, a rosin acid salt or an alkyl sulfate. Specifically, sodium, potassium or ammonium salts of aliphatic carboxylic acids such as laurate, myristate, palmitate, stearate, linoleate, linolenate; disproportionation of natural rosin Or sodium salt, potassium salt or ammonium salt of hydrogenated product; sodium salt, potassium salt or ammonium salt of aliphatic sulfate compound such as lauryl sulfate; polyoxyethylene octyl phenyl ether sulfonate, polyoxyethylene octyl phenyl ether sulfate Examples thereof include sodium salts, potassium salts, and ammonium salts of nonionic anionic emulsifiers such as ester salts. In the emulsion polymerization, a nonionic emulsifier such as polyoxyethylene octylphenyl ether or polyoxyethylene nonylphenyl ether or a protective colloid agent such as polyvinyl alcohol may be used in combination.

  The amount of the emulsifier is not particularly limited as long as it does not impair the stability of the emulsion, but is a monomer that forms the polymer (A) from the viewpoint of removal after emulsion polymerization and environmental contamination due to waste water. And preferably in the range of 0.01 to 15 parts by mass, and in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the sum of the monomers forming the polymer (B). More preferably, it is still more preferably in the range of 1 to 7 parts by mass. Such an emulsifier may be usually dispersed in water from the beginning of emulsion polymerization before the monomer is added, or may be added during the polymerization reaction.

  The polymerization initiator used in the emulsion polymerization is not particularly limited as long as it has radical polymerization initiating ability. Specifically, azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2 Azo compounds such as' -azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate; Inorganic peroxides such as sodium, potassium persulfate and hydrogen peroxide; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide. These may be used alone or in combination of two or more. Such a polymerization initiator may be added to water from the beginning of emulsion polymerization, or may be added during the polymerization reaction.

  The amount of the polymerization initiator used is 0.01 to 15 parts by mass with respect to 100 parts by mass of the sum of the monomer that forms the polymer (A) and the monomer that forms the polymer (B). The range is preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass.

In addition, from the viewpoint of productivity, a redox initiator may be used, and the redox initiator is preferably a combination of the organic peroxide and the transition metal salt.
Examples of transition metal salts used in combination with organic peroxides include iron (II) sulfate, iron (II) thiosulfate, iron (II) carbonate, iron (II) chloride, iron (II) bromide, and iron iodide. Iron compounds such as (II), iron hydroxide (II), iron oxide (II); copper sulfate (I), copper thiosulfate (I), copper carbonate (I), copper chloride (I), copper bromide ( Copper compounds such as I), copper iodide (I), copper hydroxide (I), copper oxide (I), or hydrates thereof can be used.
Among these, from the viewpoint of productivity, the combined use of the organic peroxide and the iron compound is preferable, the combined use of cumene hydroperoxide and the iron compound is more preferable, and the water of cumene hydroperoxide and iron (II) sulfate is more preferable. The combined use with a Japanese thing is still more preferable.
The amount of the organic peroxide used is 0.01 to 15 parts by mass with respect to 100 parts by mass of the sum of the monomer that forms the polymer (A) and the monomer that forms the polymer (B). The range of 0.1-5 mass parts is more preferable.
The amount of the transition metal salt used is 0.001 to 0.2 mass with respect to 100 mass parts of the sum of the monomer that forms the polymer (A) and the monomer that forms the polymer (B). The range of parts is preferable, and the range of 0.005 to 0.1 parts by mass is more preferable.

  The organic peroxide may be used not only at the start of emulsion polymerization but also added during the polymerization reaction. The amount added during the polymerization reaction is not particularly limited as long as it does not impair the modification effect of the produced coated polymer particles, but from the viewpoint of the toluene swelling index of the obtained coated polymer particles, A range of 0.0001 to 0.1% by mass with respect to water at the start of polymerization is preferred. As a method of additional addition of the organic peroxide to the polymerization reaction system, either continuous addition or intermittent addition may be used.

  In the emulsion polymerization, a desired amount of a reducing agent, a metal ion chelating agent, an electrolyte, or the like may be added as necessary. Specific examples include reducing agents such as sodium hydroxymethanesulfinate and sodium ascorbate, metal ion chelating agents such as disodium ethylenediaminetetraacetate, and electrolytes such as sodium chloride, sodium sulfate, and trisodium phosphate. These reducing agent, metal ion chelating agent, and electrolyte may be added during the polymerization reaction, but are preferably added to water from the beginning of the emulsion polymerization.

When performing the emulsion polymerization, a chain transfer agent conventionally used in emulsion polymerization can be used to adjust the toluene swelling index.
The chain transfer agent is not particularly limited as long as it has chain transfer ability in radical polymerization of farnesene. Specifically, mercaptan compounds such as n-dodecyl mercaptan and t-dodecyl mercaptan; dimethylxanthogen disulfide, Examples thereof include xanthogen disulfide compounds such as diethyl xanthogen disulfide and diisopropyl xanthogen disulfide; thiuram disulfide compounds such as tetramethylthiuram disulfide and tetraethylthiuram disulfide; halogenated hydrocarbon compounds such as carbon tetrachloride. Among these, mercaptan compounds such as n-dodecyl mercaptan and t-dodecyl mercaptan are preferable from the viewpoint of chain transfer ability with respect to farnesene. These chain transfer agents may be added to water from the beginning of emulsion polymerization or may be added during the polymerization reaction.
The amount of the chain transfer agent used is preferably 5 parts by mass or less with respect to 100 parts by mass of the sum of the monomer that forms the polymer (A) and the monomer that forms the polymer (B). Less than the mass part is more preferable.

  In order to make the coated polymer particles of the present invention have a desired toluene swelling index, it can be adjusted by the addition amount of the polymerization initiator and chain transfer agent, but it can also be adjusted by adding a crosslinking agent before adding the polymerization terminator. it can. The compound used for crosslinking is not particularly limited as long as it has the ability to initiate the crosslinking reaction of olefins. Specific examples include hydrogen peroxide, cumene hydroperoxide, p-menthane hydroperoxide, and the like. Oxides; azo compounds such as azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); sulfur And so on.

The emulsion polymerization is preferably performed under stirring conditions such that the environment in the system is uniform, and is preferably performed in an inert gas atmosphere such as nitrogen or argon.
The polymerization temperature of the emulsion polymerization is not particularly limited, but is preferably 5 to 80 ° C and more preferably 20 to 70 ° C from the viewpoint of the polymerization rate and the stability of the emulsion.
The pressure condition during the emulsion polymerization depends on the vapor pressure and the amount of the compound to be used, but is appropriately selected from normal pressure to high pressure (about 1 MPa).

In step 1, the method for adding the monomer for forming the polymer (A) is preferably intermittent addition and more preferably continuous addition from the viewpoint of emulsion stability at the time of monomer addition.
In the emulsion polymerization of the monomer forming the polymer (A), the monomer conversion rate is preferably 60% by mass or more, more preferably 80% by mass or more, and 90% by mass or more. Is more preferable. This conversion rate can be confirmed by measuring the mass of the solid content precipitated from the emulsion by the method described in Examples.

In Step 1, after producing an emulsion of particles (x) containing the polymer (A) by emulsion polymerization, in Step 2, the polymer (B) is further formed in the emulsion obtained in Step 1. A monomer is added and emulsion polymerization is performed to form an outermost film covering at least a part of the particles (x).
In step 2, the method for adding the monomer for forming the polymer (B) is preferably intermittent addition, more preferably continuous addition, from the viewpoint of the stability of the emulsion during monomer addition.
When adding a monomer, you may add the said emulsifier, a polymerization initiator, a reducing agent, a metal ion chelating agent, an electrolyte, a chain transfer agent, etc. as needed.
In the emulsion polymerization of the monomer forming the polymer (B), the monomer conversion rate is preferably 60% by mass or more, more preferably 80% by mass or more, and 90% by mass or more. Is more preferable. This conversion rate can be confirmed by measuring the mass of the solid content precipitated from the emulsion by the method described in Examples.

  After forming the outermost film containing the polymer (B) by emulsion polymerization, the polymerization can be stopped by adding a polymerization terminator. Examples of such a polymerization terminator include amine compounds such as hydroxylamine and sodium dimethyldithiocarbamate, and phenol compounds such as hydroquinone and p-methoxyphenol. These may be used individually by 1 type, or may use 2 or more types together. The addition amount of the polymerization terminator is in the range of 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of monomers normally used. The polymerization terminator may be added after mixing with water to prepare an aqueous solution, suspension, emulsion or the like.

From the emulsion containing the coated polymer particles thus obtained, the coated polymer particles can be recovered by a general method of taking out the emulsion polymer such as salting out, acid precipitation, spray drying method and freezing method. You may remove a residual monomer by heating etc. before collection | recovery.
In the salting out, the coated polymer particles can be recovered by using a coagulant generally used in emulsion polymerization. Specifically, monovalent metal salts such as sodium chloride, potassium chloride, sodium acetate, potassium acetate, sodium sulfate, potassium sulfate, sodium carbonate, potassium carbonate; calcium chloride, magnesium chloride, calcium acetate, magnesium acetate, calcium sulfate Divalent metal salts such as magnesium sulfate, calcium carbonate and magnesium carbonate; trivalent metal salts such as aluminum chloride and aluminum sulfate; and polymer flocculants. These coagulants may be used alone or in combination of two or more.
In the acid precipitation, the coated polymer particles can be recovered by using an acid compound generally used in emulsion polymerization. Specific examples include hydrochloric acid, acetic acid, sulfuric acid and the like. These acid compounds may be used alone or in combination of two or more.

The average dispersed particle size of the particles (x) containing the polymer (A) in the emulsion during the emulsion polymerization and the coated polymer particles in the emulsion after the completion of the emulsion polymerization is the monomer and water used in the emulsion polymerization. The addition ratio, the type or amount of the emulsifier, the polymerization temperature, the type or amount of the electrolyte can be adjusted. The particle size can adjust the polymerization rate and the physical properties and dispersibility of the coated polymer particles. From the viewpoint of polymerization stability, the average dispersed particle size of the coated polymer particles in the emulsion during production is 10 to 10. 200 nm is preferable, 20 to 100 nm is more preferable, and 30 to 80 nm is still more preferable. The average dispersed particle size is measured by the method described in the examples.

  The toluene swelling index of the particles (x) containing the polymer (A) and the coated polymer particles is the polymerization temperature, polymerization time, type or amount of polymerization initiator, type or amount of chain transfer agent when performing emulsion polymerization. It can be adjusted by the kind or amount of the monomer, the kind or amount of the crosslinking agent, and the like.

[Resin modifier]
The resin modifier of the present invention includes the coated polymer particles and can be used by being dispersed in a resin serving as a matrix.
By mixing the resin modifier of the present invention and the resin used as a matrix, it is possible to impart excellent processability to the resin composition and improve wear resistance in tire applications. A resin composition having excellent rolling resistance performance can be obtained.
There are no particular restrictions on the resin used as the matrix, but various rubbers such as natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, isobutylene-isoprene copolymer, styrene-isoprene copolymer, styrene-isoprene- Examples thereof include a butadiene copolymer, a halogenated isobutylene-isoprene copolymer, an ethylene-propylene-diene copolymer, an acrylonitrile-butadiene copolymer, a partial hydrogenated product of an acrylonitrile-butadiene copolymer, and polychloroprene. These may be used individually by 1 type, or may use 2 or more types together.

As the rubber, a modified rubber having a functional group introduced may be used. Examples of such functional groups include epoxy groups, hydroxyl groups, amino groups, alkoxysilyl groups, etc. Specific examples of the modified rubber include epoxy group-modified natural rubber, hydroxyl group-modified styrene-butadiene copolymer, amino group-modified styrene- Examples thereof include a butadiene copolymer and an alkoxysilyl group-modified styrene-butadiene copolymer.
The rubber may contain a β-farnesene homopolymer in the range of, for example, 0.1 to 50 parts by mass with respect to 100 parts by mass of the rubber.

When using the coated polymer particles of the present invention as a resin modifier, it is preferable to use 0.1 to 100 parts by weight of the coated polymer particles of the present invention with respect to 100 parts by weight of the resin serving as a matrix. It is more preferable to use -50 mass parts, and it is still more preferable to use 1-30 mass parts.
Further, the resin modifier of the present invention is an antioxidant, an antioxidant, a wax, a lubricant, a light stabilizer, a scorch inhibitor, a processing aid, as necessary, as long as the effects of the present invention are not impaired. 1 type of additives such as colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, antifungal agents, and perfumes Or you may contain 2 or more types.

[Rubber composition]
The rubber composition of the present invention is a rubber composition containing a rubber component (X) containing the above-mentioned coated polymer particles and a filler (Y), wherein the coated polymer particles in the total amount of the rubber component (X) Content is 1-50 mass%, and 20-150 mass parts of fillers (Y) are contained with respect to 100 mass parts of rubber components (X).

<Rubber component (X)>
In the present invention, examples of the rubber component (X) include natural rubber; styrene-butadiene copolymer, polybutadiene, polyisoprene, isobutylene-isoprene copolymer, styrene-isoprene copolymer, and styrene-isoprene-butadiene copolymer. , Halogenated isobutylene-isoprene copolymer, ethylene-propylene-diene copolymer, acrylonitrile-butadiene copolymer, partial hydrogenated product of acrylonitrile-butadiene copolymer, and synthetic rubber such as polychloroprene. Among these, from the viewpoint of improving moldability and braking performance, at least one selected from the group consisting of natural rubber; synthetic rubber such as styrene-butadiene copolymer, polybutadiene, and polyisoprene is preferable. These rubbers may be used alone or in combination of two or more.

[Natural rubber]
The natural rubber used as the rubber component (X) is, for example, natural rubber generally used in the tire industry such as TMR and RSS such as SMR, SIR and STR, high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, Examples thereof include modified natural rubbers such as hydrogenated natural rubber and grafted natural rubber. Among these, SMR20, STR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability. These natural rubbers may be used alone or in combination of two or more. When two or more kinds of natural rubber are used in combination, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical property value can be adjusted by the combination.

[Synthetic rubber]
Synthetic rubber used as the rubber component (X) is styrene-butadiene copolymer, polybutadiene, polyisoprene, isobutylene-isoprene copolymer, styrene-isoprene copolymer, styrene-isoprene-butadiene copolymer, halogenated isobutylene- At least one selected from the group consisting of an isoprene copolymer, an ethylene-propylene-diene copolymer, an acrylonitrile-butadiene copolymer, a partial hydrogenated product of an acrylonitrile-butadiene copolymer, and a polychloroprene is preferable. More preferred is at least one selected from the group consisting of a butadiene copolymer, polyisoprene, and polybutadiene. When two or more synthetic rubbers are mixed and used, the combination can be arbitrarily selected within a range not impairing the effects of the present invention, and the physical property values can be adjusted by the combination. Moreover, these manufacturing methods are not specifically limited, What is marketed can be used.

(Styrene-butadiene copolymer)
As the styrene-butadiene copolymer, those commonly used for tire applications can be used. Specifically, those having a styrene content of 0.1 to 70% by mass are preferred, and those having a styrene content of 5 to 50% by mass. Is more preferable. Moreover, the content (vinyl content) of the bonding mode excluding 1,4 bonds in the butadiene monomer unit in the copolymer is preferably 0.1 to 60% by mass, More preferred.
The weight average molecular weight (Mw) of the styrene-butadiene copolymer is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and further preferably 200,000 to 1,500,000. When it is within the above range, both moldability and the mechanical strength of the obtained tire can be achieved.

  The glass transition temperature (Tg) obtained by differential thermal analysis of the styrene-butadiene copolymer used in the present invention is preferably −95 to 0 ° C., more preferably −95 to −5 ° C. When the Tg is in the above range, the rubber composition can be prevented from increasing in viscosity, and the handling becomes easy.

The styrene-butadiene copolymer that can be used in the present invention is obtained by copolymerizing styrene and butadiene. There is no restriction | limiting in particular about the manufacturing method of a styrene-butadiene copolymer, Any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used, An emulsion polymerization method and a solution polymerization method are preferable.
The styrene-butadiene copolymer can be produced by an ordinary emulsion polymerization method, and is obtained, for example, by emulsifying and dispersing a predetermined amount of styrene and a butadiene monomer in the presence of an emulsifier, and emulsion polymerization with a radical polymerization initiator. . Moreover, in order to adjust the molecular weight of the styrene-butadiene copolymer obtained by emulsion polymerization, a chain transfer agent can also be used. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The copolymer can be recovered as crumb by adding the acid and coagulating the copolymer while adjusting the pH of the coagulation system to a predetermined value and then separating the dispersion solvent. The crumb is washed with water, then dehydrated, and dried with a band dryer or the like to obtain the desired emulsion-polymerized styrene-butadiene copolymer.

The styrene-butadiene copolymer can be produced by a usual solution polymerization method, for example, by copolymerizing styrene and butadiene in the presence of a polar compound, if desired, using an anion-polymerizable active metal in a solvent. Can be manufactured. As an anion-polymerizable active metal, an alkali metal and an alkaline earth metal are preferable, an alkali metal is more preferable, and an organic alkali metal compound is further preferable.
Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4- Polyfunctional organolithium compounds such as dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined depending on the required molecular weight of the styrene-butadiene copolymer obtained by solution polymerization.
Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene and toluene And aromatic hydrocarbons. These solvents are usually preferably used in a range where the monomer concentration is 1 to 50% by mass.

The polar compound is not particularly limited as long as it is usually used for adjusting the microstructure of the butadiene moiety and the distribution of styrene in the copolymer chain without deactivating the reaction in anionic polymerization. For example, dibutyl ether Ether compounds such as tetrahydrofuran and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides and phosphine compounds.
The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. The polymerization mode may be either a batch type or a continuous type. The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. A polymerization terminal modifier may be added before the polymerization terminator is added. After the polymerization reaction is stopped, the solvent can be separated by direct drying, steam stripping or the like, and the target solution-polymerized styrene-butadiene copolymer can be recovered. In addition, before removing the solvent, the polymerization solution and the extending oil may be mixed in advance and recovered as an oil-extended rubber.

  In the present invention, a modified styrene-butadiene copolymer having a functional group introduced into the styrene-butadiene copolymer may be used as long as the effects of the present invention are not impaired. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxyl group, an epoxy group, and a carboxyl group. In this modified styrene-butadiene copolymer, the position at which the functional group in the polymer is introduced may be the polymer end or the side chain of the polymer.

(Polyisoprene)
As polyisoprene, for example, a commercially available polyisoprene obtained by polymerization using a Ziegler catalyst, a lanthanoid rare earth metal catalyst, an organic alkali metal compound, or the like can be used. Among these, polyisoprene obtained by polymerization using a Ziegler catalyst is preferable from the viewpoint of a high cis isomer content. Moreover, you may use the polyisoprene of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.
The vinyl content of polyisoprene is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content is 50% by mass or less, the rolling resistance performance is good. The lower limit of the vinyl content is not particularly limited.

The glass transition temperature (Tg) of polyisoprene varies depending on the vinyl content, but is preferably −20 ° C. or lower, more preferably −30 ° C. or lower.
The weight average molecular weight (Mw) of polyisoprene is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When the weight average molecular weight is within the above range, the moldability and the mechanical strength of the resulting tire are good.
The polyisoprene is partially branched by using a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a structure or a polar functional group.

(Polybutadiene)
As the polybutadiene, for example, a commercially available polybutadiene obtained by polymerization using a Ziegler catalyst, a lanthanoid rare earth metal catalyst, an organic alkali metal compound, or the like can be used. Among these, polybutadiene obtained by polymerization using a Ziegler catalyst is preferable from the viewpoint of a high cis isomer content. Moreover, you may use the polybutadiene of the ultra-high cis body content obtained using a lanthanoid type rare earth metal catalyst.
The vinyl content of the polybutadiene is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. When the vinyl content is 50% by mass or less, the rolling resistance performance is good. The lower limit of the vinyl content is not particularly limited.

The glass transition temperature (Tg) of polybutadiene varies depending on the vinyl content, but is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower.
The weight average molecular weight (Mw) of the polybutadiene is preferably 90,000 to 2,000,000, more preferably 150,000 to 1,500,000, and even more preferably 250,000 to 800,000. When the weight average molecular weight is in the above range, the moldability and the mechanical strength of the resulting tire are good.
The polybutadiene is partially branched by using a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. Or you may have a polar functional group.

<Filler (Y)>
The rubber composition of this invention contains 20-150 mass parts of fillers (Y) with respect to 100 mass parts of rubber components (X). By using the filler (Y), physical properties such as mechanical strength, heat resistance, and weather resistance are improved, and the hardness can be adjusted and the amount of the rubber composition can be increased.
Fillers (Y) used in the present invention include oxides such as silica and titanium oxide; silicates such as clay, talc, mica, glass fiber and glass balloon; carbonates such as calcium carbonate and magnesium carbonate; magnesium hydroxide And hydroxides such as aluminum hydroxide; sulfates such as calcium sulfate and barium sulfate; inorganic fillers such as carbons such as carbon black and carbon fiber; organic fillers such as resin particles, wood powder and cork powder. . These may be used alone or in combination of two or more.

(Content of each component)
Content of the coating polymer particle in a rubber composition is 1-50 mass% in rubber component (X) total amount, 2-30 mass% is preferable and it is more preferable to use 3-10 mass%. When the content of the coated polymer particles is in the above range, workability, wear resistance, and rolling resistance performance are improved.
Content of the filler (Y) in a rubber composition is 20-150 mass parts with respect to 100 mass parts of rubber components (X), 25-130 mass parts is preferable and 30-110 mass parts is more preferable. . When the content of the filler (Y) is in the above range, molding processability, braking performance, mechanical strength, and wear resistance are improved.

<Optional component>
(Silane coupling agent)
The rubber composition of the present invention preferably contains a silane coupling agent. Examples of the silane coupling agent include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, and chloro compounds.
Examples of sulfide compounds include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (2-trimethoxysilyl). Ethyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N Examples include dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide and 3-trimethoxysilylpropyl methacrylate monosulfide. It is done.
Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the like.

Examples of the vinyl compound include vinyl triethoxysilane and vinyl trimethoxysilane.
Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxy. Silane etc. are mentioned.
Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. Can be mentioned.
Examples of the nitro compound include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.
Examples of the chloro compound include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.
These may be used alone or in combination of two or more. Among these, a sulfide compound and a mercapto compound are preferable from the viewpoint of the effect of addition and cost, and bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, and 3-mercapto. More preferred is propyltrimethoxysilane.

  When the silane coupling agent is contained, the content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the filler (Y). 1 to 15 parts by mass is more preferable. When the content of the silane coupling agent is within the above range, dispersibility, coupling effect, reinforcement, and tire wear resistance are improved.

(Crosslinking agent)
The rubber composition of the present invention is preferably used after being crosslinked (vulcanized) by adding a crosslinking agent. Examples of the crosslinking agent include sulfur and sulfur compounds, oxygen, organic peroxides, phenol resins and amino resins, quinones and quinone dioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organometallic halogens. And silane compounds other than silane coupling agents. Of these, sulfur and sulfur compounds are preferred. These may be used alone or in combination of two or more. The content of the crosslinking agent is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and still more preferably 0.8 to 5 parts by mass with respect to 100 parts by mass of the rubber component (X). .

  Among the crosslinking agents, when sulfur and a sulfur compound are used, the rubber composition of the present invention can be vulcanized and used as a vulcanized rubber. Although there are no particular limitations on the vulcanization conditions and method, it is preferably carried out using a vulcanization mold under a pressure heating condition of a vulcanization temperature of 120 to 200 ° C. and a vulcanization pressure of 0.5 to 2.0 MPa.

  The rubber composition of the present invention may contain a vulcanization accelerator. Examples of the vulcanization accelerator include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds or aldehyde-ammonia compounds, imidazolines. Compounds, xanthate compounds, and the like. These may be used alone or in combination of two or more. When it contains the said vulcanization accelerator, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (X), and 0.1-10 mass parts is more preferable.

  The rubber composition of the present invention may further contain a vulcanization aid. Examples of the vulcanization aid include fatty acids such as stearic acid; metal oxides such as zinc white; and fatty acid metal salts such as zinc stearate. These may be used alone or in combination of two or more. When the said vulcanization | cure adjuvant is contained, 0.1-15 mass parts is preferable with respect to 100 mass parts of rubber components (X), and 1-10 mass parts is more preferable.

(Other ingredients)
The rubber composition of the present invention is intended to improve molding processability, fluidity, etc. within a range that does not impair the effects of the invention, and if necessary, silicon oil, aroma oil, TDAE (Treated Distilled Aromatic Extracts), MES ( Mild Extracted Solvates), RAE (Residual Aromatic Extracts), paraffin oil, naphthenic oil and other process oils, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, C9 resins, rosin resins, coumarone-indene resins, Resin components such as phenolic resins, liquid polymers such as low molecular weight polybutadiene, low molecular weight polyisoprene, low molecular weight styrene-butadiene copolymers, and low molecular weight styrene-isoprene copolymers can be used as softeners as appropriate. . The copolymer may be in any polymerization form such as block or random. The weight average molecular weight of the liquid polymer is preferably 500 to 100,000 from the viewpoint of molding processability.

The rubber composition of the present invention is an anti-aging agent, an antioxidant, a wax, a lubricant, a light as needed for the purpose of improving the weather resistance, heat resistance, oxidation resistance, etc., as long as the effects of the invention are not impaired. Stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, fungicides One or more additives such as an agent and a fragrance may be contained.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, and hydroquinone compounds.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenol compounds, sulfur compounds, and phosphorus compounds.

(Method for producing rubber composition)
The method for producing the rubber composition of the present invention is not particularly limited, and the components may be mixed uniformly. Examples of the uniform mixing method include a tangential or meshing closed kneader such as a kneader ruder, a brabender, a banbury mixer, an internal mixer, a single screw extruder, a twin screw extruder, a mixing roll, and a roller. Usually, and can be carried out in a temperature range of 70 to 270 ° C.

[tire]
The tire of the present invention is a tire using at least a part of the rubber composition. Therefore, workability, wear resistance, and rolling resistance performance are good. The rubber composition of the present invention can be used for various members of tires, and can be suitably used particularly as tire treads for passenger cars, truck buses, motorcycles and industrial vehicles.
In addition, you may use the crosslinked material which bridge | crosslinked the rubber composition of this invention for the tire of this invention. A tire using the rubber composition of the present invention or a crosslinked product of the rubber composition of the present invention can maintain characteristics such as wear resistance and rolling resistance performance even when used for a long time.
A tire made of a rubber composition containing the coated polymer particles of the present invention is excellent in wear resistance and rolling resistance performance.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.

(Monomer)
・ Β-farnesene: Amiris, manufactured by Incorporated ・ Butadiene: manufactured by JSR Corporation ・ Styrene: manufactured by Kishida Chemical Co., Ltd. ・ Methacrylic acid: manufactured by Wako Pure Chemical Industries, Ltd. 2-hydroxybutyl methacrylate: trade name “Light Ester HOB (N)”, manufactured by Kyoeisha Chemical Co., Ltd. (emulsifier)
-Sodium lauryl sulfate: trade name "Sinoline 100", manufactured by Shin Nippon Rika Co., Ltd. (polymerization initiator)
Cumene hydroperoxide: trade name “Park Mill H-80”, manufactured by NOF Corporation (polymerization terminator)
・ Hydroquinone: Tokyo Chemical Industry Co., Ltd. (reducing agent)
・ Iron sulfate (II) (7 hydrate): Wako Pure Chemical Industries, Ltd. ・ Longalite: Wako Pure Chemical Industries, Ltd. (additive)
・ Ethylenediaminetetraacetic acid disodium dihydrogen: manufactured by Kanto Chemical Co., Ltd.
・ Sodium chloride: Wako Pure Chemical Industries, Ltd. (solvent)
・ Ion-exchanged water: Ion-exchanged water with an electric conductivity of 0.08 × 10 ⁻⁴ S / m or less ・ Toluene: Wako Pure Chemical Industries, Ltd. (anti-aging agent)
-K-840: manufactured by Chukyo Yushi Co., Ltd. (additive for salting out)
・ Potassium chloride: Wako Pure Chemical Industries, Ltd. (staining agent)
・ Osmium tetroxide: Nisshin EM Co., Ltd.

In the examples and comparative examples, various analysis conditions were performed according to the following methods.
[Monomer conversion rate]
An emulsion (1 ml) sampled every hour from the start of the polymerization was dropped into acetone (20 ml) to precipitate the coated polymer particles or the polymer particles. After the sedimentation of the particles, the supernatant liquid is removed, and the obtained solid content is reduced to 0 using a vacuum dryer (square vacuum constant temperature dryer model: DP23, manufactured by Yamato Scientific Co., Ltd.) until there is no change in mass. Vacuum drying was performed under the conditions of 1 kPa and 60 ° C.
The monomer conversion rate (%) was calculated from the mass of the sampled emulsion, the concentration of the monomer at the start of emulsion polymerization, and the mass of the solid content after drying.

[Average dispersion particle size in emulsion]
After adding the monomer mixture (iii), which will be described later in Step 2, a mixture of the emulsion (0.1 ml) and ion-exchanged water (10 ml) sampled before the addition of the polymerization terminator is used as a dynamic light scattering measurement device (device). Name: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.), the particle size distribution of the particles was measured on a volume basis, and the median diameter was measured as the average dispersed particle diameter.
In Comparative Examples 3 and 4, the emulsion was sampled after the monomer mixture (ii) was added and before the polymerization terminator was added.

[Average particle size]
6.8 parts by mass of the coated polymer particle or polymer particle emulsion after addition of the polymerization terminator is mixed with 100 parts by mass of the polymethyl methacrylate emulsion (solid content concentration: 40%), and -15 ° C. Co-deposited by freezing in The obtained solid was press-molded at 200 ° C. for 1 minute to obtain a resin sheet. After dyeing the sheet with osmium tetroxide, the particle image obtained by observing with a transmission electron microscope (device name: transmission electron microscope HT7700, manufactured by Hitachi High-Technologies Corporation) is a number average from 100 particle diameters. The average particle diameter of the coated polymer particles or polymer particles was obtained as a value.
[Average thickness]
The average particle diameter of the particles (x) is measured by the same method as above except that the emulsion of the particles (x) is used in place of the coated polymer particles or the emulsion of polymer particles, and the above measurement is performed. The average thickness was obtained from the difference from the average particle diameter of the coated polymer particles.

[Toluene swelling index]
The coated polymer particles or polymer particles immersed in toluene were shaken for 24 hours so that the solid concentration was about 1% by mass to obtain a toluene solution containing a toluene swell. The toluene solution containing the swollen body was treated at 20,000 rpm for 1 hour using a centrifuge (device name: hymac CR 22GII, manufactured by Hitachi Koki Co., Ltd.), and solid-liquid separation was performed. Subsequently, after taking out the solid layer containing the swollen body and measuring the mass (α), it was vacuum-dried under the conditions of 0.1 kPa and 60 ° C. using the vacuum dryer until the mass change of the swollen body disappeared, and toluene The toluene swelling index (α / β) was calculated from the ratio of the mass before drying (α) and the mass after drying (β).

The rubber compositions obtained in Examples and Comparative Examples were evaluated by the following methods.
[Machinability]
In accordance with JIS K6300, the Mooney viscosity (ML1 + 4) of the rubber composition before vulcanization was measured at 100 ° C., and the reciprocal thereof was used as an index of processability of the rubber composition. Each numerical value in Table 4 is a relative value when the value of Comparative Example 1 is set to 100. The larger the value, the better the workability.

[Abrasion resistance]
Measure the DIN wear amount at a wear distance of 40 m under a load of 10 N in accordance with JIS K6264 using the vulcanized sheet produced by the method described later, and calculate the reciprocal of the DIN wear amount (1 / DIN wear amount). It was used as an index of wear resistance. Each numerical value in Table 4 is a relative value when the value of Comparative Example 1 is set to 100. Larger values indicate less wear and better wear resistance.

[Rolling resistance performance]
A 40 mm long x 7 mm wide test piece was cut out from a vulcanized sheet produced by the method described below, and measured using a dynamic viscoelasticity measuring device manufactured by GABO, measuring temperature 60 ° C., frequency 10 Hz, static strain 10%, dynamic Tan δ was measured under the condition of 2% static strain, and its reciprocal (1 / tan δ) was used as an index of rolling resistance performance. Each numerical value in Table 4 is a relative value when the value of Comparative Example 1 is set to 100. The larger the value, the better the rolling resistance performance.

Example 1
(Preparation of initiator emulsion)
An emulsion containing 3.45 g of cumene hydroperoxide as a polymerization initiator, 3.75 g of sodium lauryl sulfate as an emulsifier, and 150 g of ion-exchanged water was subjected to deoxygenation to obtain an initiator emulsion.
(Production of coated polymer particles (1-1))
(Process 1)
In a dried 0.5 L pressure-resistant polymerization tank, 200 g of ion-exchanged water, 5 g of sodium lauryl sulfate, 0.032 g of iron (II) sulfate (7 hydrate), 0.02 g of disodium ethylenediaminetetraacetate, 0% of sodium chloride After adding 2 g, deoxygenation was performed by bubbling with nitrogen gas for 30 minutes to obtain an aqueous solution.
After raising the temperature of the aqueous solution to 60 ° C., the monomer mixture (ii) shown in Table 1 was deoxygenated and then added. Subsequently, polymerization was started by continuously adding the initiator emulsion at a rate of 0.02 ml / min, and an emulsion of particles (x) was obtained.
(Process 2)
When it was confirmed that the total monomer conversion calculated by the above method exceeded 95% by mass, the initiator emulsion was added to the emulsion obtained in Step 1 at a rate of 0.02 ml / min. The monomer mixture (iii) shown in Table 1 was deoxygenated while feeding, and then continuously added at a rate of 1.7 ml / min.
After the addition of the monomer mixture (iii), when it was confirmed that the total monomer conversion calculated by the above method exceeded 95% by mass, the addition of the initiator emulsion was stopped, and the polymerization terminator A hydroquinone deoxygenated aqueous solution was added. The polymerization tank was cooled to 25 ° C., and the emulsion of the coated polymer particles of the present invention was taken out.
The polymerization time from the start of polymerization to the addition of the polymerization terminator was 10 hours.
After adding 0.5 g of K-840 as an anti-aging agent to the emulsion, 200 ml of 5% by weight potassium chloride aqueous solution was mixed to recover the coated polymer particles by salting out, and then using a vacuum dryer. Drying was performed at 0.1 kPa and 60 ° C. until there was no change in weight to obtain coated polymer particles (1-1). The obtained coated polymer particles were analyzed by the above method. The results are shown in Table 4.

(Manufacture of rubber composition)
According to the blending ratio (parts by mass) shown in Table 3, rubber component (X), filler (Y), silane coupling agent, vulcanization aid, anti-aging agent, and other components, TDAE and wax are sealed, respectively. The mixture was put into a banbury mixer and kneaded for 6 minutes so that the starting temperature was 50 ° C. and the resin temperature was 150 ° C., then taken out of the mixer and cooled to room temperature. Next, this mixture was again put into a Banbury mixer, and a crosslinking agent (sulfur) and a vulcanization accelerator were added and kneaded at 100 ° C. for 75 seconds to obtain 950 g of a rubber composition.
The obtained rubber composition was press-molded (160 ° C., 25 minutes) to produce a vulcanized sheet (thickness 2 mm) and evaluated based on the above method. The results are shown in Table 4.

Examples 2-6
(Production of coated polymer particles (1-2) to (1-6) and a rubber composition)
After using the monomer mixture shown in Table 1 to obtain coated polymer particles (1-2) to (1-6) in the same manner as in Example 1, the blending ratio (parts by mass) shown in Table 3 was obtained. Thus, a rubber composition was obtained in the same manner as in Example 1. Each of the obtained coated polymer particles and the rubber composition was evaluated by the above method. The results are shown in Table 4.

Example 7
(Preparation of initiator emulsion)
An initiator emulsion was obtained in the same manner as in the preparation of the initiator emulsion in Example 1.
(Production of coated polymer particles (1-7))
(Step 1-1)
In a dried 0.5 L pressure-resistant polymerization tank, 200 g of ion-exchanged water, 5 g of sodium lauryl sulfate, 0.032 g of iron (II) sulfate (7 hydrate), 0.02 g of disodium ethylenediaminetetraacetate, 0% of sodium chloride After adding 2 g, deoxygenation was performed by bubbling with nitrogen gas for 30 minutes to obtain an aqueous solution.
After raising the temperature of the aqueous solution to 60 ° C., the monomer mixture (i) shown in Table 1 was deoxygenated and then added. Next, polymerization was started by continuously adding the initiator emulsion at a rate of 0.02 ml / min, and an emulsion of particles (x ′) was obtained.
(Step 1-2)
After confirming that the total monomer conversion calculated by the above method exceeded 95% by mass, the initiator emulsion was added to the emulsion obtained in Step 1-1 at a rate of 0.02 ml / min. The monomer mixture (ii) shown in Table 1 was deoxygenated while being fed at 0, and then continuously added at a rate of 1.7 ml / min to obtain an emulsion of particles (x).
(Process 2)
After the addition of the monomer mixture (ii), when it was confirmed that the total monomer conversion calculated by the above method exceeded 95% by mass, the monomer mixture (iii) shown in Table 1 was removed. After oxygen treatment, it was continuously added at a rate of 1.7 ml / min.
After the addition of the monomer mixture (iii), when it was confirmed that the total monomer conversion calculated by the above method exceeded 95% by mass, the addition of the initiator emulsion was stopped, and the polymerization terminator A hydroquinone deoxygenated aqueous solution was added. Thereafter, the polymerization tank was cooled to 25 ° C., and the emulsion of the coated polymer particles of the present invention was taken out.
The polymerization time from the start of polymerization to the addition of the polymerization terminator was 10 hours.
After adding 0.5 g of K-840 as an anti-aging agent to the emulsion, 200 ml of 5% by weight potassium chloride aqueous solution was mixed to recover the coated polymer particles by salting out, and then using a vacuum dryer. Drying was performed at 0.1 kPa and 60 ° C. until there was no change in weight to obtain coated polymer particles (1-7). The obtained coated polymer particles were analyzed by the above method. The results are shown in Table 4.
(Manufacture of rubber composition)
According to the compounding ratio (parts by mass) shown in Table 3, a rubber composition was obtained in the same manner as in Example 1. About the obtained rubber composition, it evaluated by the said method. The results are shown in Table 4.

Examples 8-10
(Production of coated polymer particles (1-8) to (1-10) and a rubber composition)
After using the monomer mixture shown in Table 1 to obtain coated polymer particles (1-8) to (1-10) in the same manner as in Example 7, the blending ratio (parts by mass) shown in Table 3 was obtained. Thus, a rubber composition was obtained in the same manner as in Example 1. Each of the obtained coated polymer particles and the rubber composition was evaluated by the above method. The results are shown in Table 4.

Comparative Examples 1 and 2
(Production of coated polymer particles (2-1) and (2-2))
Using the monomer mixture shown in Table 2, coated polymer particles (2-1) and (2-2) were obtained in the same manner as in Example 1. Each of the obtained coated polymer particles was analyzed by the above method. The results are shown in Table 4.
(Manufacture of rubber composition)
According to the compounding ratio (parts by mass) shown in Table 3, a rubber composition was obtained in the same manner as in Example 1. Each rubber composition obtained was evaluated by the above method. The results are shown in Table 4.

Comparative Examples 3 and 4
(Preparation of initiator emulsion)
An initiator emulsion was obtained in the same manner as in the preparation of the initiator emulsion in Example 1.
(Production of polymer particles (2-3) and (2-4))
In a dried 0.5 L pressure-resistant polymerization tank, 200 g of ion-exchanged water, 5 g of sodium lauryl sulfate, 0.032 g of iron (II) sulfate (7 hydrate), 0.02 g of disodium ethylenediaminetetraacetate, 0% of sodium chloride After adding 2 g, deoxygenation was performed by bubbling with nitrogen gas for 30 minutes to obtain an aqueous solution.
After raising the temperature of the aqueous solution to 60 ° C., the monomer mixture (ii) shown in Table 2 was deoxygenated and then added. Next, the polymerization was started by continuously adding the initiator emulsion at a rate of 0.02 ml / min. When it was confirmed that the total monomer conversion calculated by the above method exceeded 95% by mass, the addition of the initiator emulsion was stopped, and a deoxygenated aqueous solution of hydroquinone as a polymerization terminator was added. Thereafter, the polymerization tank was cooled to 25 ° C., and an emulsion of polymer particles was taken out.
The polymerization time from the start of polymerization to the addition of the polymerization terminator was 10 hours.
After adding 0.5 g of K-840 as an anti-aging agent to the emulsion, polymer particles were taken out by salting out by mixing 200 ml of a 2% by mass aqueous potassium chloride solution. The obtained polymer particles were dried with a vacuum dryer at 0.1 kPa and 60 ° C. until there was no change in weight to obtain polymer particles (2-3) and (2-4). Each polymer particle obtained was analyzed by the above method. The results are shown in Table 4.
(Manufacture of rubber composition)
According to the compounding ratio (parts by mass) shown in Table 3, a rubber composition was obtained in the same manner as in Example 1. Each rubber composition obtained was evaluated by the above method. The results are shown in Table 4.

Each component in Table 3 is as follows.
[Rubber component (X)]
Styrene-butadiene copolymer: modified terminal hydroxyl group, Mw: 500,000, styrene content 23% by mass, vinyl content 54% by mass
Polybutadiene: “BR01” (manufactured by JSR Corporation, Mw: 550,000, cis isomer content: 95% by mass)
[Filler (Y)]
Silica: “ULTRASIL 7000GR” (Evonik Japan Co., Ltd.)
Carbon black: Diamond Black N234 (Mitsubishi Chemical Corporation)
〔Silane coupling agent〕
Silane coupling agent: Si75 (manufactured by Evonik Japan Co., Ltd.)
[Crosslinking agent]
Sulfur: Jinhua stamp fine powder sulfur 200 mesh (manufactured by Tsurumi Chemical Co., Ltd.)
[Vulcanization accelerator]
Vulcanization accelerator (1): Sunseller NS-G (manufactured by Sanshin Chemical Industry Co., Ltd.)
Vulcanization accelerator (2): Noxeller D (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (3): Noxeller MP (Ouchi Shinsei Chemical Co., Ltd.)
[Vulcanization aid]
Stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
[Other ingredients]
Anti-aging agent: NOCRACK 6C (Ouchi Shinsei Chemical Co., Ltd.)
TDAE: VivaTec500 (H & R)
Wax: Suntite S (manufactured by Seiko Chemical Co., Ltd.)

Each notation in Table 4 is as follows.
* 1: Numerical values in parentheses in Table 4 indicate the content (% by mass) of each monomer in each polymer.
* 2: Indicates the average particle diameter of the coated polymer particles or polymer particles.
* 3: Indicates the ratio between the average particle diameter of the particles (x) and the average thickness of the outermost coating.

  From Table 4, the rubber composition using the coated polymer particles of Examples 1 to 10 is excellent in workability and wear resistance while maintaining excellent rolling resistance performance as compared with Comparative Examples 1 to 4. This shows that the rolling resistance performance is compatible with workability and wear resistance.

The coated polymer particles of the present invention are useful as a resin modifier capable of suppressing deterioration in processability of rubber and improving wear resistance while maintaining excellent rolling resistance performance in tire applications. A rubber composition containing coalesced particles can be suitably used as a rubber composition for a tire or the like having excellent processability and excellent wear resistance and rolling resistance performance.

Claims (13)

Coated polymer particles having particles (x) and an outermost coating covering at least a portion of the particles (x),
The particle (x) contains a polymer (A) containing a monomer unit derived from farnesene,
Coated polymer particles, wherein the outermost coating contains a polymer (B).   The coating weight according to claim 1, wherein the polymer (A) is a copolymer comprising a monomer unit derived from farnesene and a monomer unit derived from another radical polymerizable monomer (a). Coalesced particles.   Content of the monomer unit derived from the radically polymerizable monomer (a) in a polymer (A) is 5-95 mass% with respect to the total mass of a polymer (A). Coated polymer particles.   The radical polymerizable monomer (a) is composed of a conjugated diene other than farnesene, an aromatic vinyl compound, (meth) acrylic acid and its salt, (meth) acrylic acid ester, and (N-alkyl) (meth) acrylamide. The coated polymer particle according to claim 2 or 3, which is at least one selected from the group.   The coated polymer particle according to any one of claims 1 to 4, wherein the polymer (B) is a polymer containing a monomer unit derived from a conjugated diene.   The polymer (B) is a copolymer containing a monomer unit derived from a conjugated diene and a monomer unit derived from another radical polymerizable monomer (b), and the radical polymerizable monomer 2. (b) is at least one selected from the group consisting of aromatic vinyl compounds, (meth) acrylic acid and salts thereof, (meth) acrylic acid esters, and (N-alkyl) (meth) acrylamides. The coated polymer particle according to any one of -5.   The content of the monomer unit derived from the radically polymerizable monomer (b) in the polymer (B) is 1 to 80% by mass with respect to the total mass of the polymer (B). Coated polymer particles.   Radical polymerizable monomer (b) is (meth) acrylic acid and its salt, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid N, N′-dialkylaminoalkyl The coated polymer particle according to claim 6 or 7, which is at least one selected from the group consisting of esters, (meth) acrylic acid trialkoxysilylalkyl esters, and (N-alkyl) (meth) acrylamides.   The coated polymer according to any one of claims 1 to 8, wherein the mass ratio of the particles (x) to the outermost coating [particle (x) / outermost coating] is in the range of 95/5 to 50/50. particle.   The coated polymer according to any one of claims 1 to 9, wherein the particle (x) is a particle having a coating composed of at least one layer covering at least a part of the particle (x ') and the particle (x'). particle.   The resin modifier containing the covering polymer particle in any one of Claims 1-10.   A rubber composition comprising the rubber component (X) comprising the coated polymer particles according to any one of claims 1 to 10 and a filler (Y), wherein the coated polymer in the total amount of the rubber component (X) A rubber composition having a particle content of 1 to 50% by mass and containing 20 to 150 parts by mass of filler (Y) with respect to 100 parts by mass of rubber component (X).   A tire using at least a part of the rubber composition according to claim 12.