JP6036079B2 - Rubber composition for studless tire and studless tire - Google Patents

Description

  The present invention relates to a rubber composition for studless tires and a studless tire.

  For the purpose of improving the friction on ice and wear resistance of studless tires, a rubber composition for studless tires containing a plasticizer has been developed.

For example, in Patent Document 1, the present applicant states that “(A) 100 parts by weight of at least one rubber selected from natural rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, polyisoprene rubber and butyl rubber” (B) 30 to 80 parts by weight of carbon black and / or silica, and (C) a compound having a polyisobutylene-based main chain and at least one alkoxysilyl group and / or a main chain of the formula —R ¹ —O— (formula R ¹ is a polyether system having a repeating unit represented by a divalent hydrocarbon group having 1 to 8 carbon atoms) and 3 to 50 parts by weight of a compound having at least one alkoxysilyl group. The tread rubber composition for studless tires ”is proposed ([Claim 1]).

JP-A-11-91310

  However, when the present inventors repeatedly examined the rubber composition described in Patent Document 1, it was revealed that the performance on ice tends to be improved, but the wear resistance may be inferior. .

  Then, this invention makes it a subject to provide the rubber composition for studless tires which can produce the studless tire excellent in both on-ice performance and abrasion resistance, and a studless tire using the same.

As a result of intensive investigations to solve the above problems, the present inventors have blended a predetermined cross-linkable oligomer or polymer together with polyisobutylene fine particles having a specific particle size, so that either on-ice performance or wear resistance can be achieved. And found that an excellent studless tire can be produced, and completed the present invention.
That is, the present invention provides the following (1) to (11).

(1) 100 parts by mass of diene rubber (A),
30 to 100 parts by mass of carbon black and / or white filler (B),
0.3 to 30 parts by mass of a crosslinkable oligomer or polymer (C),
Containing 0.1 to 12 parts by mass of three-dimensionally crosslinked fine particles (D) having an average particle diameter of 1 to 200 μm,
The fine particles (D) are polyisobutylene fine particles,
A rubber composition for studless tires, wherein the content of the fine particles (D) is 1 to 50% by mass with respect to the total mass of the crosslinkable oligomer or polymer (C) and the fine particles (D).

  (2) In the above (1), the fine particle (D) is a fine particle obtained by three-dimensionally crosslinking the oligomer or polymer (d1) having an isobutylene monomer unit in the crosslinkable oligomer or polymer (C) in advance. The rubber composition for studless tires as described.

  (3) The diene rubber (A) is natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), styrene-isoprene rubber. (SIR), styrene-isoprene-butadiene rubber (SIBR), and studless as described in (1) or (2) above containing at least one rubber selected from the group consisting of derivatives of each of these rubbers Rubber composition for tires.

  (4) The crosslinkable oligomer or polymer (C) is a polyether-based, polyester-based, polyolefin-based, polycarbonate-based, aliphatic-based, saturated hydrocarbon-based, acrylic-based, plant-derived polymer or siloxane-based polymer or copolymer. The rubber composition for studless tires according to any one of (1) to (3), which is a polymer.

  (5) The crosslinkable oligomer or polymer (C) is at least selected from the group consisting of a hydroxyl group, a silane functional group, an isocyanate group, a (meth) acryloyl group, an allyl group, a carboxy group, an acid anhydride group, and an epoxy group. The rubber composition for studless tires according to any one of the above (1) to (4), which has one or more reactive functional groups.

(6) The oligomer or polymer (d1) is a reactive functional group different from the reactive functional group of the crosslinkable oligomer or polymer (C), and includes a hydroxyl group, a mercapto group, a silane functional group, an isocyanate group, Having at least one reactive functional group selected from the group consisting of (meth) acryloyl group, allyl group, carboxy group, acid anhydride group and epoxy group,
The fine particles (D) are fine particles that are three-dimensionally crosslinked using the reactive functional group of the oligomer or polymer (d1) in the crosslinkable oligomer or polymer (C). Rubber composition for studless tires.

  (7) The fine particles (D) are selected from the group consisting of the oligomer or polymer (d1) having the reactive functional group and a compound having water, a catalyst, and a functional group that reacts with the reactive functional group. The rubber composition for a studless tire according to (6), wherein the rubber composition is three-dimensionally cross-linked by reacting at least one component (d2).

  (8) The rubber composition for studless tires according to (7), wherein the compound having a functional group that reacts with the reactive functional group in the component (d2) is a silanol compound and / or a hydrosilane compound.

  (9) The rubber composition for studless tires according to any one of (1) to (8), wherein the fine particles (D) have an average particle diameter of 1 to 50 μm.

  (10) The rubber composition for studless tires according to any one of (1) to (9), wherein the average glass transition temperature of the diene rubber (A) is −50 ° C. or lower.

  (11) A studless tire using the rubber composition for a studless tire according to any one of (1) to (10) as a tire tread.

  As shown below, according to the present invention, it is possible to provide a rubber composition for a studless tire capable of producing a studless tire excellent in both on-ice performance and wear resistance, and a studless tire using the same. it can.

It is a typical fragmentary sectional view of the tire showing an example of the embodiment of the studless tire of the present invention.

[Rubber composition for studless tire]
The rubber composition for studless tires of the present invention (hereinafter also referred to as “the rubber composition for tires of the present invention”) comprises 100 parts by mass of a diene rubber (A) and carbon black and / or white filler (B). Contains 30 to 100 parts by mass, crosslinkable oligomer or polymer (C) 0.3 to 30 parts by mass, and three-dimensionally crosslinked fine particles (D) 0.1 to 12 parts by mass with an average particle diameter of 1 to 200 μm The fine particles (D) are polyisobutylene fine particles, and the content of the fine particles (D) is 1 to 50% by mass based on the total mass of the crosslinkable oligomer or polymer (C) and the fine particles (D). This is a rubber composition for studless tires.
Below, each component which the rubber composition for tires of this invention contains is demonstrated in detail.

<Diene rubber (A)>
The diene rubber (A) contained in the tire rubber composition of the present invention is not particularly limited as long as it has a double bond in the main chain, and specific examples thereof include natural rubber (NR) and isoprene rubber. (IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), and the like. These may be used alone or in combination of two or more.
The diene rubber (A) is a derivative in which the terminal or side chain of each rubber is modified (modified) with an amino group, amide group, silyl group, alkoxy group, carboxy group, hydroxy group, epoxy group or the like. It may be.
Among these, NR, BR, and SBR are preferably used, and NR and BR are more preferably used in combination, because the performance on ice of the studless tire becomes better.

In the present invention, the average glass transition temperature of the diene rubber (A) is −50 ° C. or less because the hardness of the studless tire can be kept low even at low temperatures and the performance on ice is better. Is preferred.
Here, the glass transition temperature is a value measured at a heating rate of 10 ° C./min according to ASTM D3418-82 using a differential thermal analyzer (DSC) manufactured by DuPont.
The average glass transition temperature is an average value of the glass transition temperature. When only one diene rubber is used, the glass transition temperature of the diene rubber is used. When two or more diene rubbers are used in combination, Means the glass transition temperature of the entire diene rubber (mixture of each diene rubber), and can be calculated as an average value from the glass transition temperature of each diene rubber and the blending ratio of each diene rubber.

  In the present invention, 20 mass% or more of the diene rubber (A) is preferably NR, and more preferably 40 mass% or more is NR because the strength of the studless tire is good. .

<Carbon black and / or white filler (B)>
The rubber composition for tires of the present invention contains carbon black and / or a white filler (B).

(Carbon black)
Specific examples of the carbon black include furnace carbon blacks such as SAF, ISAF, HAF, FEF, GPE, and SRF. These may be used alone or in combination of two or more. May be.
In addition, the carbon black preferably has a nitrogen adsorption specific surface area (N ₂ SA) of 10 to 300 m ² / g from the viewpoint of processability when mixing the rubber composition, reinforcement of the studless tire, and the like. more preferably from 200 m ² / g, to improve the wet performance of the studless tire, for the reasons ice performance becomes better, is preferably from 50 to 150 m ² / g, in 70~130m ² / g More preferably.
Here, N ₂ SA is a value obtained by measuring the amount of nitrogen adsorbed on the carbon black surface in accordance with JIS K 6217-2: 2001 “Part 2: Determination of specific surface area—nitrogen adsorption method—single point method”. .

(White filler)
Specific examples of the white filler include silica, calcium carbonate, magnesium carbonate, talc, clay, alumina, aluminum hydroxide, titanium oxide, calcium sulfate, and the like. Or two or more of them may be used in combination.
Among these, silica is preferable because the performance on ice of the studless tire becomes better.

Specific examples of silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like, and these may be used alone. Two or more kinds may be used in combination.
Among these, wet silica is preferable because the performance on ice of the studless tire is further improved and the wear resistance is further improved.

The silica preferably has a CTAB adsorption specific surface area of 50 to 300 m ² / g, more preferably 70 to 250 m ² / g, because the wet performance and rolling resistance of the studless tire are good. More preferably, it is -200 m < ² > / g.
Here, the CTAB adsorption specific surface area was determined by measuring the adsorption amount of n-hexadecyltrimethylammonium bromide on the silica surface according to JIS K6217-3: 2001 “Part 3: Determination of specific surface area—CTAB adsorption method”. Value.

In the present invention, the content of the carbon black and / or the white filler (B) is 30 to 100 parts by mass in total of the carbon black and the white filler with respect to 100 parts by mass of the diene rubber (A). It is preferably 40 to 90 parts by mass, and more preferably 45 to 80 parts by mass.
Moreover, when using the said carbon black and the said white filler together, it is preferable that content of the said white filler is 5-85 mass parts with respect to 100 mass parts of the said diene rubber (A), 15 More preferably, it is -75 mass parts.

<Crosslinkable oligomer or polymer (C)>
The crosslinkable oligomer or polymer (C) contained in the tire rubber composition of the present invention is not particularly limited, and may be compatible with or not compatible with the diene rubber (A). .
Here, “(compatible with the diene rubber)” does not mean that it is compatible with all the rubber components included in the diene rubber (A), but the diene rubber (A And the specific components used in the crosslinkable oligomer or polymer (C) are compatible with each other.
Similarly, “incompatible with (in the diene rubber)” does not mean that it is incompatible with all the rubber components included in the diene rubber (A), but the diene rubber (A And the specific components used in the crosslinkable oligomer or polymer (C) are incompatible with each other.
In the present invention, the above-mentioned crosslinkable oligomer or polymer (C) improves the dispersibility in the rubber composition and improves the performance on ice and the wear resistance of the studless tire. Those that are not compatible with each other are preferred.

  Examples of the crosslinkable oligomer or polymer (C) include polyether, polyester, polyolefin, polycarbonate, aliphatic, saturated hydrocarbon, acrylic, plant-derived or siloxane-based polymers or copolymers. A polymer etc. are mentioned.

  Among these, from the viewpoint of improving the performance on ice and wear resistance of the studless tire, the crosslinkable oligomer or polymer (C) is a polyether-based, polycarbonate-based or acrylic-based polymer or copolymer. Preferably there is.

Here, examples of the polyether polymer or copolymer include polyethylene glycol, polypropylene glycol (PPG), polypropylene triol, ethylene oxide / propylene oxide copolymer, polytetramethylene ether glycol (PTMEG), and sorbitol. Based polyols and the like.
Examples of the polycarbonate-based polymer or copolymer include esters of polyol compounds (for example, 1,6-hexanediol, 1,4-butanediol, 1,5-pentanediol, etc.) and dialkyl carbonate. Examples thereof include those obtained by exchange reaction.
In addition, examples of the acrylic polymer or copolymer include acrylic polyols; homopolymers of acrylates such as acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; and combinations of two or more of these acrylates. Acrylate copolymer; and the like.

In the present invention, the crosslinkable oligomer or polymer (C) is a hydroxyl group, a silane functional group, an isocyanate group, (meth) acryloyl, because the performance on ice of a studless tire is improved by crosslinking between molecules. It preferably has at least one reactive functional group selected from the group consisting of a group, an allyl group, a carboxy group, an acid anhydride group and an epoxy group.
Here, the silane functional group is also called a so-called crosslinkable silyl group. Specific examples thereof include hydrolyzable silyl group; silanol group; silanol group as acetoxy group derivative, enoxy group derivative, oxime group derivative, amine derivative. And the like.
Among these functional groups, the above-mentioned crosslinkable oligomer or polymer (C) is appropriately crosslinked at the time of rubber processing, and the performance on ice of the studless tire is further improved and the wear resistance is also improved. It preferably has an isocyanate group, an acid anhydride group or an epoxy group, and more preferably has a silane functional group (particularly a hydrolyzable silyl group) and / or an isocyanate group.

Here, specific examples of the hydrolyzable silyl group include an alkoxysilyl group, an alkenyloxysilyl group, an acyloxysilyl group, an aminosilyl group, an aminooxysilyl group, an oximesilyl group, and an amidosilyl group. It is done.
Among these, an alkoxysilyl group is preferable because of a good balance between hydrolyzability and storage stability. Specifically, an alkoxysilyl group represented by the following formula (1) is preferable. More preferred are a methoxysilyl group and an ethoxysilyl group.

(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, a represents an integer of 1 to 3. a is 2 or 3) In this case, the plurality of R ¹ may be the same or different, and when a is 1, the plurality of R ¹ may be the same or different.)

Moreover, the said isocyanate group is an isocyanate group which remains when the hydroxyl group of a polyol compound (for example, polycarbonate-type polyol etc.) and the isocyanate group of a polyisocyanate compound are made to react.
The polyisocyanate compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. Specific examples thereof include TDI (for example, 2,4-tolylene diisocyanate (2,4-TDI). ), 2,6-tolylene diisocyanate (2,6-TDI)), MDI (for example, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4 ' -MDI)), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), Triphenylme Aromatic polyisocyanates such as polytriisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI); transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis (isocyanatemethyl) cyclohexane (H ₆ XDI), alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate (H ₁₂ MDI); these carbodiimide-modified polyisocyanates; these isocyanurate-modified polyisocyanates; It is done.

  In the present invention, when a crosslinkable oligomer or polymer (C) having a hydroxyl group as a reactive functional group is used, the crosslinkable oligomer or polymer is previously added with an isocyanate compound or the like before blending with the diene rubber (A). It is preferable that a part or all of (C) is crosslinked, or a crosslinking agent such as an isocyanate compound is blended in advance with the rubber.

  In the present invention, the reactive functional group is preferably at least at the end of the main chain of the crosslinkable oligomer or polymer (C), and when the main chain is linear, 1.5 is present. It is preferable to have the above, and it is more preferable to have two or more. On the other hand, when the main chain is branched, it is preferably 3 or more.

In the present invention, the weight-average molecular weight or number-average molecular weight of the crosslinkable oligomer or polymer (C) improves dispersibility in the diene rubber (A) and kneading processability of the rubber composition. It is preferably 300 to 30000, and preferably 500 to 25000, because the particle size and shape can be easily adjusted when the fine particles (D) described later are prepared in the crosslinkable oligomer or polymer (C). Is more preferable.
Here, the weight average molecular weight and the number average molecular weight are both measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

  Furthermore, in this invention, content of the said crosslinkable oligomer or polymer (C) is 0.3-30 mass parts with respect to 100 mass parts of said diene rubbers (A), and 0.5-25 masses. Parts, preferably 1 to 15 parts by mass.

<Fine particles (D)>
The fine particles (D) contained in the tire rubber composition of the present invention are three-dimensionally crosslinked polyisobutylene fine particles having an average particle diameter of 1 to 200 μm.
The average particle size of the fine particles (D) is preferably 1 to 50 μm, and more preferably 5 to 40 μm, because the surface of the studless tire becomes moderately rough and the performance on ice is better. Is more preferable.
Here, the average particle diameter means an average value of equivalent circle diameters measured using a laser microscope. For example, a laser diffraction scattering type particle size distribution measuring apparatus LA-300 (manufactured by Horiba, Ltd.), a laser microscope VK- 8710 (manufactured by Keyence) or the like.

In the present invention, the content of the fine particles (D) is 0.1 to 12 parts by mass, preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the diene rubber (A). 0.5 to 10 parts by mass is more preferable.
Moreover, content of the said microparticles | fine-particles (D) is 1-50 mass% with respect to the total mass of the said crosslinkable oligomer or polymer (C) and the said microparticles | fine-particles (D), and it is 3-30 mass%. Preferably, it is 5-20 mass%.
By containing a predetermined amount of the fine particles (D), the performance on ice and the wear resistance of a studless tire using the tire rubber composition of the present invention for a tire tread are both good.
This is presumably because the on-ice performance and wear resistance were improved because the strain applied locally was dispersed and the stress was relieved by the elasticity of the fine particles (D).

Further, in the present invention, the fine particles (D) contain isobutylene monomer units in the crosslinkable oligomer or polymer (C) in advance for the reason that the performance on ice and wear resistance of the studless tire becomes better. It is preferably fine particles obtained by three-dimensionally cross-linking the oligomer or polymer (d1). This is because the crosslinkable oligomer or polymer (C) and the fine particles (C) function as a solvent for the fine particles (D), and when the mixture thereof is blended into the rubber composition. This is probably because the dispersibility and dispersibility of the rubber composition (D) can be expected to be improved. Therefore, from the viewpoint of further improving these functions and effects, the oligomer or polymer (d1) is preferably incompatible with the crosslinkable oligomer or polymer (C).
Here, “(incompatible with the crosslinkable oligomer or polymer (C))” does not mean that it is incompatible with all components included in the crosslinkable oligomer or polymer (C). The specific components used for the crosslinkable oligomer or polymer (C) and the oligomer or polymer (d1) are incompatible with each other.

The oligomer or polymer (d1) is not particularly limited as long as it is an oligomer or polymer having an isobutylene monomer unit.
Because the crosslinkable oligomer or polymer (C) can be three-dimensionally cross-linked only in the oligomer or polymer (d1), the reaction is different from the above-mentioned reactive functional group of the crosslinkable oligomer or polymer (C). At least one selected from the group consisting of hydroxyl groups, mercapto groups, silane functional groups, isocyanate groups, (meth) acryloyl groups, allyl groups, carboxy groups, acid anhydride groups, and epoxy groups. It preferably has a reactive functional group.
Here, the silane functional group is also referred to as a so-called crosslinkable silyl group, and specific examples thereof include, for example, a hydrolyzable silyl group; silanol, similar to the silane functional group of the crosslinkable oligomer or polymer (C). Groups; functional groups in which silanol groups are substituted with acetoxy group derivatives, enoxy group derivatives, oxime group derivatives, amine derivatives, and the like.
After the oligomer or polymer (d1) is three-dimensionally crosslinked, the crosslinkable oligomer or polymer (C) is the same reactive functional group as the oligomer or polymer (d1) (for example, a carboxy group, A hydrolyzable silyl group or the like), and the functional functional group already possessed may be modified to the same reactive functional group as the oligomer or polymer (d1).
Among these functional groups, it is more preferable to have a silane functional group (particularly a hydrolyzable silyl group) or an allyl group because the three-dimensional crosslinking of the oligomer or polymer (d1) easily proceeds.

  Examples of commercially available oligomers or polymers (d1) having such a reactive functional group include hydrolyzable silyl group-terminated polyisobutylene (EP705S, number average molecular weight: 17000, manufactured by Kaneka Corporation), hydrolyzable silyl group. Examples include terminal polyisobutylene (S-303S, number average molecular weight: 15000, manufactured by Kaneka Corporation), allyl group terminal polyisobutylene (EP200A, number average molecular weight: 5000, manufactured by Kaneka Corporation), and the like.

  In the present invention, the reactive functional group is preferably at least at the end of the main chain of the oligomer or polymer (d1). When the main chain is linear, 1.5 or more are present. It is preferable to have two or more. On the other hand, when the main chain is branched, it is preferably 3 or more.

In the present invention, the weight average molecular weight or number average molecular weight of the oligomer or polymer (d1) is not particularly limited, but the particle diameter and crosslinking density of the fine particles (D) become appropriate, and the performance on ice of the studless tire is further improved. From the reason of becoming favorable, it is preferable that it is 1000-100000, and it is more preferable that it is 3000-60000.
Here, both weight average molecular weight or number average molecular weight shall be measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

(Preparation method of fine particles (D))
The method for preparing the fine particles (D) by three-dimensionally crosslinking the oligomer or polymer (d1) in the crosslinkable oligomer or polymer (C) includes, for example, the reactive functional group of the oligomer or polymer (d1). Examples include a method of three-dimensional crosslinking using, specifically, the oligomer or polymer (d1) having the reactive functional group and a functional group that reacts with water, a catalyst, and the reactive functional group. Examples thereof include a method of reacting at least one component (d2) selected from the group consisting of compounds with three-dimensional crosslinking.

  Here, the water of the component (d2) is preferably used when the oligomer or polymer (d1) has a hydrolyzable silyl group, an isocyanate group, or an acid anhydride group as a reactive functional group. it can.

Examples of the component (d2) catalyst include a silanol group condensation catalyst (silanol condensation catalyst).
Specific examples of the silanol condensation catalyst include dibutyltin dilaurate, dibutyltin dioleate, dibutyltin diacetate, tetrabutyl titanate, and stannous octoate.

  Moreover, as a compound which has a functional group which reacts with the said reactive functional group of the said component (d2), a silanol compound, a hydrosilane compound, etc. are mentioned, for example.

The silanol compound can be suitably used when the oligomer or polymer (d1) has a silane functional group as a reactive functional group.
Specific examples of the silanol compound include tert-butyldimethylsilanol, diphenylmethylsilanol, polydimethylsiloxane having a silanol group, and cyclic polysiloxane having a silanol group.

The hydrosilane compound is a compound having a SiH group, and can be suitably used when the oligomer or polymer (d1) has an allyl group as a reactive functional group.
Specific examples of the hydrosilane compound include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyltetracyclosiloxane, 1,3,5,7,8- Examples include pentamethylpentacyclosiloxane.
When the hydrosilane compound is used, a catalyst that promotes the reaction with the (meth) acrylic compound (d1) having an allyl group (for example, from a group VIII transition metal element such as platinum, rhodium, cobalt, palladium, nickel, etc.) A selected metal complex catalyst) can be used.

In the present invention, when preparing the fine particles (D) by three-dimensionally crosslinking the oligomer or polymer (d1) in the crosslinkable oligomer or polymer (C), a solvent may be used as necessary. .
The use mode of the solvent is a mode in which a plasticizer, a diluent, or a solvent is used as a good solvent for the oligomer or polymer (d1) and a poor solvent for the crosslinkable oligomer or polymer (C), and / or Examples include using a plasticizer, a diluent, and a solvent that are good solvents for the crosslinkable oligomer or polymer (C) and that are poor solvents for the oligomer or polymer (d1).
Specific examples of such a solvent include n-pentane, isopentane, neopentane, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, 2-methylhexane, 3-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 3-ethylpentane, 2,2 Aliphatic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; Aromatic hydrocarbons such as xylene, benzene and toluene; α-pinene, Examples include terpene organic solvents such as β-pinene and limonene.

  In the present invention, when preparing the fine particles (D) by three-dimensionally crosslinking the oligomer or polymer (d1) in the crosslinkable oligomer or polymer (C), a surfactant, an emulsifier, a dispersant, It is preferable to prepare using an additive such as a silane coupling agent.

<Silane coupling agent>
When the tire rubber composition of the present invention contains the above-described white filler (particularly silica), it is preferable to contain a silane coupling agent for the purpose of improving the reinforcing performance of the studless tire.
The content when the silane coupling agent is blended is preferably 0.1 to 20 parts by mass and more preferably 4 to 12 parts by mass with respect to 100 parts by mass of the white filler.

  Specific examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, Bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy Silane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N- Methylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl Methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, Dimethoxymethylsilylpropylbenzothiazole tetrasulfide and the like, and these may be used alone, It may be used alone or species.

  Of these, bis- (3-triethoxysilylpropyl) tetrasulfide and / or bis- (3-triethoxysilylpropyl) disulfide is preferably used from the viewpoint of reinforcing effect. Specifically, Examples thereof include Si69 [bis- (3-triethoxysilylpropyl) tetrasulfide; manufactured by Evonik Degussa], Si75 [bis- (3-triethoxysilylpropyl) disulfide; manufactured by Evonik Degussa).

<Other ingredients>
In addition to the components described above, the rubber composition for tires of the present invention includes the diene rubber (A), the carbon black and / or white filler (B), the crosslinkable oligomer or polymer (C), and the above In addition to fine particles (D), fillers such as calcium carbonate; vulcanizing agents such as sulfur; vulcanization accelerators such as sulfenamide-based, guanidine-based, thiazole-based, thiourea-based, and thiuram-based materials; zinc oxide, stearic acid, etc. Various other additives generally used in rubber compositions for tires, such as vulcanization accelerators; waxes; aroma oils; anti-aging agents; plasticizers;
As long as the amount of these additives is not contrary to the object of the present invention, a conventional general amount can be used. For example, for 100 parts by mass of the diene rubber (A), 0.5 to 5 parts by mass of sulfur, 0.1 to 5 parts by mass of the vulcanization accelerator, and 0.1 to 10 parts by mass of the vulcanization accelerator aid. Parts, anti-aging agent 0.5-5 parts by mass, wax 1-10 parts by mass, aroma oil 5-30 parts by mass, respectively.

<Method for producing rubber composition for tire>
The method for producing the tire rubber composition of the present invention is not particularly limited. For example, the above-described components are kneaded using a known method or apparatus (for example, a Banbury mixer, a kneader, a roll, or the like). Is mentioned.
The tire rubber composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

〔studless tire〕
The studless tire of the present invention (hereinafter also simply referred to as “the tire of the present invention”) is a studless tire using the above-described tire rubber composition of the present invention for a tire tread.
FIG. 1 shows a schematic partial sectional view of a tire representing an example of an embodiment of the studless tire of the present invention, but the tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, the code | symbol 1 represents a bead part, the code | symbol 2 represents a sidewall part, and the code | symbol 3 represents the tread part comprised from the rubber composition for tires of this invention.
Further, a carcass layer 4 in which fiber cords are embedded is mounted between the pair of left and right bead portions 1, and the end of the carcass layer 4 extends from the inside of the tire to the outside around the bead core 5 and the bead filler 6. Wrapped and rolled up.
In the tire tread 3, a belt layer 7 is disposed over the circumference of the tire on the outside of the carcass layer 4.
Moreover, in the bead part 1, the rim cushion 8 is arrange | positioned in the part which touches a rim | limb.

  The tire of the present invention is vulcanized or cured at a temperature corresponding to, for example, the diene rubber used in the tire rubber composition of the present invention, the type of vulcanization or crosslinking agent, the type of vulcanization or crosslinking accelerator, and the blending ratio thereof. It can manufacture by bridge | crosslinking and forming a tire tread part.

<Preparation of fine particle-containing crosslinkable polymer 1>
Hydroxyl-terminated polyoxypropylene glycol (preminol S-4012, number average molecular weight: 10000, hydroxyl value 11.2, manufactured by Asahi Glass Co., Ltd.) and 3-isocyanatopropyltriethoxysilane (A-1310, Momentive Performance Materials) 26 g) (manufactured by Japan Godo Kaisha) was put into a three-necked flask and stirred at 80 ° C. for 8 hours to obtain a hydrolyzable silyl group-terminated polyether.
Next, 100 g of allyl group-terminated polyisobutylene (EP200A, number average molecular weight: 5000, manufactured by Kaneka Corp.), 0.08 g of acetylene alcohol, 12 g of hydrosilane compound (CR-300, manufactured by Kaneka Corp.), 0.1 g of platinum catalyst, After kneading for 5 minutes, the entire amount was immediately charged into the hydrolyzable silyl group-terminated polyether synthesized earlier.
After the addition, the temperature was raised to 120 ° C. while stirring was continued, and stirring was continued at 120 ° C. for 2 hours. Thereafter, by cooling to room temperature, a cloudy pasty product (hereinafter also referred to as “fine-particle-containing crosslinkable polymer 1”) was prepared.
When this pasty product is observed using a laser microscope VK-8710 (manufactured by Keyence Corporation), fine particles (skeleton: isobutylene monomer unit, cross-linking: Si—C bond) having an average particle diameter of 10 μm are generated, It was confirmed that it was dispersed in the hydrolyzable silyl group-terminated polyoxypropylene glycol. Further, as a result of image processing and 3D profiling of this image, the content (% by mass) of fine particles in the pasty product was about 15%.

<Preparation of fine particle-containing crosslinkable polymer 2>
Hydroxyl group-containing acrylic polyol (ARUFON UH-2000, weight average molecular weight: 11000, hydroxyl value 20, manufactured by Toagosei Co., Ltd.), 4 g of a mixture of water and ethanol (mixing ratio = 1: 2), and an organic tin compound (MSCAT) -01, manufactured by Nippon Chemical Industry Co., Ltd.) was sufficiently mixed with stirring. To this, 150 g of hydrolyzable silyl group-terminated polyisobutylene (EP705S, number average molecular weight: 17000, manufactured by Kaneka Corporation) was added, and the mixture was heated to 50 ° C. and stirred for 5 hours.
Then, after raising the temperature to 120 ° C. and performing vacuum deaeration for 2 hours, the temperature was lowered to 60 ° C., 12 g of a dehydrating agent (vinyltrimethoxysilane, KBM1003, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3-isocyanatopropyltriethoxysilane. (A-1310, manufactured by Momentive Performance Materials Japan LLC) was added to 55.0 g, and the mixture was heated to 80 ° C. and stirred for 8 hours. Thereafter, by cooling to room temperature, a cloudy pasty product (hereinafter also referred to as “fine particle-containing crosslinkable polymer 2”) was prepared.
When this pasty product is observed using a laser microscope VK-8710 (manufactured by Keyence Corporation), fine particles (skeleton: isobutylene monomer unit, cross-linking: siloxane bond) having an average particle diameter of 15 μm are generated and hydrolyzed. It was confirmed that it was dispersed in the polymerizable silyl group-terminated acrylic polymer. Further, as a result of image processing and 3D profiling of this image, the content (% by mass) of fine particles in the pasty product was about 15%.

<Preparation of fine particle-containing crosslinkable polymer 3>
800 g of polycarbonate diol (Duranol T5652, number average molecular weight: 2000, hydroxyl value 56, manufactured by Asahi Kasei Chemicals), 4 g of a mixture of water and ethanol (mixing ratio = 1: 2), and an organic tin compound (MSCAT-01, Nippon Kagaku) 10 g (manufactured by Sangyo Co., Ltd.) was sufficiently stirred and mixed. To this, 150 g of hydrolyzable silyl group-terminated polyisobutylene (EP705S, number average molecular weight: 17000, manufactured by Kaneka Corporation) was added, and the mixture was heated to 50 ° C. and stirred for 5 hours.
Then, after raising the temperature to 120 ° C. and performing vacuum deaeration for 2 hours, the temperature was lowered to 50 ° C., and 12 g of a dehydrating agent (vinyltrimethoxysilane, KBM1003, manufactured by Shin-Etsu Chemical Co., Ltd.) and xylylene diisocyanate (XDI) ( (Mitsui Chemicals) 112g was added, and it heated up at 80 degreeC, and stirred for 6 hours. Thereafter, by cooling to room temperature, a cloudy pasty product (hereinafter also referred to as “fine-particle-containing crosslinkable polymer 3”) was prepared.
When this pasty product is observed using a laser microscope VK-8710 (manufactured by Keyence Corporation), fine particles (skeleton: isobutylene monomer unit, cross-linking: siloxane bond) having an average particle diameter of 15 μm are formed, and an isocyanate group It was confirmed that it was dispersed in the terminal polycarbonate polymer. Further, as a result of image processing and 3D profiling of this image, the content (% by mass) of fine particles in the pasty product was about 15%.

<Preparation of fine particle-containing crosslinkable polymer 4>
100 g of allyl group-terminated polyisobutylene (EP200A, number average molecular weight: 5000, manufactured by Kaneka), 0.08 g of acetylene alcohol, 12 g of hydrosilane compound (CR-300, manufactured by Kaneka), and 0.1 g of platinum catalyst After kneading for a minute, the entire amount was immediately charged into 600 g of hydroxyl-terminated polytetramethylene ether glycol (PTMEG) (Poly THF650S, manufactured by BASF).
After the addition, the temperature was raised to 120 ° C. while stirring was continued, and stirring was continued at 120 ° C. for 2 hours. Then, after cooling to 50 ° C., 28 g of xylylene diisocyanate (XDI) (manufactured by Mitsui Chemicals), 54 g of 3-isocyanatopropyltriethoxysilane (A-1310, manufactured by Momentive Performance Materials Japan GK) Was added, and the mixture was heated to 80 ° C. and stirred for 6 hours.
Thereafter, by cooling to room temperature, a cloudy pasty product (hereinafter also referred to as “fine-particle-containing crosslinkable polymer 4”) was prepared.
When this pasty product is observed using a laser microscope VK-8710 (manufactured by Keyence Corporation), fine particles (skeleton: isobutylene monomer unit, cross-linking: Si—C bond) having an average particle diameter of 13 μm are generated, It was confirmed that it was dispersed in polytetramethylene ether glycol having an isocyanate group and a hydrolyzable silyl group at the terminal. Further, as a result of image processing and 3D profiling of this image, the content (% by mass) of fine particles in the pasty product was about 15%.

<Examples 1-5 and Comparative Examples 1-3>
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1 below.
Specifically, the components shown in Table 1 below, excluding sulfur and the vulcanization accelerator, were kneaded for 5 minutes with a 1.7 liter closed mixer and released when the temperature reached 150 ° C. A master batch was obtained.
Next, sulfur and a vulcanization accelerator were kneaded with an open roll in the obtained master batch to obtain a rubber composition.
Next, the obtained rubber composition was vulcanized at 170 ° C. for 15 minutes in a lamborn abrasion mold (diameter 63.5 mm, disk shape 5 mm thick) to produce a vulcanized rubber sheet.

<Performance on ice>
Each prepared vulcanized rubber sheet was affixed to a flat cylindrical base rubber, and the coefficient of friction on ice was measured with an inside drum type friction tester on ice. The measurement temperature was −1.5 ° C., the load was 5.5 g / cm ³ , and the drum rotation speed was 25 km / h.
The test results were expressed as an index according to the following formula, with the measured value of Comparative Example 1 being 100, and listed in the column “Performance on ice” in Table 1. The larger the index, the greater the frictional force on ice and the better the performance on ice.
Index = (Measured value / Coefficient of friction on ice of test piece of Comparative Example 1) × 100

<Abrasion resistance>
Using a Lambourn abrasion tester (manufactured by Iwamoto Seisakusho Co., Ltd.), in accordance with JIS K 6264-2: 2005, additional force 4.0 kg / cm ³ (= 39 N), slip rate 30%, wear test time 4 minutes, test A wear test was performed at room temperature, and the wear mass was measured.
The test results were expressed as an index according to the following formula, with the measured value of Comparative Example 1 being 100, and listed in the column of “Abrasion resistance” in Table 1. The larger the index, the smaller the amount of wear and the better the wear resistance.
Index = (Abrasion mass / measured value of test piece of Comparative Example 1) × 100

The following components were used as the components in Table 1 above.
NR: natural rubber (STR20, glass transition temperature: -65 ° C, manufactured by Bombandit)
BR: Polybutadiene rubber (Nipol BR1220, glass transition temperature: −110 ° C., manufactured by Nippon Zeon)
・ Carbon black: Show black N339 (manufactured by Cabot Japan)
Silica: ULTRASIL VN3 (Evonik Degussa)
・ Zinc oxide: 3 types of zinc oxide (manufactured by Shodo Chemical Co., Ltd.)
・ Stearic acid: Bead stearic acid YR (manufactured by NOF Corporation)
・ Anti-aging agent: Amine-based anti-aging agent (Santflex 6PPD, manufactured by Flexsys)
・ Wax: Paraffin wax (Ouchi Shinsei Chemical Co., Ltd.)
・ Silane coupling agent: Silane coupling agent (Si69, manufactured by Evonik Degussa)
Crosslinkable polymer: Hydrolyzable silyl group-terminated polyisobutylene (EP705S, number average molecular weight: 17000, manufactured by Kaneka Corporation)
-Fine-particle-containing crosslinkable polymers 1 to 4: manufactured as described above-Oil: Process oil (Extract No. 4 S, Showa Shell Sekiyu KK)
・ Sulfur: 5% oil-treated sulfur (Hosoi Chemical Co., Ltd.)
・ Vulcanization accelerator: Sulfenamide vulcanization accelerator (Sunseller CM-G, manufactured by Sanshin Chemical Co., Ltd.)

From the results shown in Table 1, although Comparative Example 2 containing only the crosslinkable oligomer or polymer (C) has a slightly improved performance on ice compared to Comparative Example 1 prepared without adding this, It was found that the wearability was inferior.
Further, although a suitable amount of fine particles (D) is blended, Comparative Example 3 with a large amount of crosslinkable oligomer or polymer (C) is more on ice than Comparative Example 1 prepared without blending fine particles. The performance was slightly improved, but the wear resistance was found to be greatly inferior.

  On the other hand, Examples 1-5 which mix | blended predetermined amount of the crosslinkable oligomer or polymer (C) and microparticles | fine-particles (D) improve the performance on ice, maintaining the outstanding abrasion resistance equivalent to or more than the comparative example 1. I found out that Especially, it turned out that Example 1 using a polyether polymer as the crosslinkable oligomer or polymer (C) has an excellent balance between performance on ice and wear resistance.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims (10)

100 parts by mass of diene rubber (A),
30 to 100 parts by mass of carbon black and / or white filler (B),
0.3 to 30 parts by mass of a crosslinkable oligomer or polymer (C),
Containing 0.1 to 12 parts by mass of three-dimensionally crosslinked fine particles (D) having an average particle diameter of 1 to 200 μm,
The crosslinkable oligomer or polymer (C) is a polyether-based, polyester-based, polyolefin-based, polycarbonate-based, aliphatic-based, saturated hydrocarbon-based, acrylic-based, plant-derived polymer or siloxane-based polymer or copolymer. Yes,
The fine particles (D) are polyisobutylene-based fine particles,
A rubber composition for studless tires, wherein the content of the fine particles (D) is 1 to 50% by mass with respect to the total mass of the crosslinkable oligomer or polymer (C) and the fine particles (D).   The studless tire according to claim 1, wherein the fine particles (D) are fine particles obtained by three-dimensionally cross-linking the oligomer or polymer (d1) having an isobutylene monomer unit in the cross-linkable oligomer or polymer (C) in advance. Rubber composition.   The diene rubber (A) is natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR). The rubber composition for studless tires according to claim 1 or 2, comprising at least 30% by mass of at least one rubber selected from the group consisting of styrene-isoprene-butadiene rubber (SIBR) and derivatives of these rubbers. The crosslinkable oligomer or polymer (C) is at least one selected from the group consisting of a hydroxyl group, a silane functional group, an isocyanate group, a (meth) acryloyl group, an allyl group, a carboxy group, an acid anhydride group, and an epoxy group. The rubber composition for studless tires according to any one of claims 1 to 3 , wherein the rubber composition has a reactive functional group. The crosslinkable oligomer or polymer (C) is at least one selected from the group consisting of a hydroxyl group, a silane functional group, an isocyanate group, a (meth) acryloyl group, an allyl group, a carboxy group, an acid anhydride group, and an epoxy group. Having a reactive functional group of
The oligomer or polymer (d1) is a reactive functional group different from the reactive functional group of the crosslinkable oligomer or polymer (C), and is a hydroxyl group, mercapto group, silane functional group, isocyanate group, (meth) Having at least one reactive functional group selected from the group consisting of an acryloyl group, an allyl group, a carboxy group, an acid anhydride group and an epoxy group;
The fine particles (D) is, in the above cross-linkable oligomer or polymer (C), according to claim 2 wherein a reactive microparticles three-dimensionally crosslinked by utilizing the functional groups of the oligomer or polymer (d1) has A rubber composition for studless tires. The fine particle (D) is at least one selected from the group consisting of the oligomer or polymer (d1) having the reactive functional group, and a compound having water, a catalyst, and a functional group that reacts with the reactive functional group. The rubber composition for studless tire according to claim 5 , which is a fine particle obtained by reacting the component (d2) with a three-dimensionally crosslinked fine particle. The rubber composition for studless tire according to claim 6 , wherein the compound having a functional group that reacts with the reactive functional group in the component (d2) is a silanol compound and / or a hydrosilane compound. The rubber composition for a studless tire according to any one of claims 1 to 7 , wherein the fine particles (D) have an average particle diameter of 1 to 50 µm. The rubber composition for studless tires according to any one of claims 1 to 8 , wherein the diene rubber (A) has an average glass transition temperature of -50 ° C or lower. Studless tire using the rubber composition for a studless tire according to the tire tread to claim 1-9.