Provided are a rubber composition for producing a foam having a high expansion ratio, a high-expansion-ratio foam, a tire, an acoustic member, a sealing material, a hose, a belt, a wire covering, a thermal insulation material, an expansion ratio improver for rubber, a method for improving the expansion ratio of a foam, and a method for producing a high-expansion-ratio foam. A rubber composition for producing a foam having a high expansion ratio, comprising the following components (a), (b), (c), and (d): (a) a rubber component; (b) a chemical foaming agent; (c) a compound represented by the following formula (1) or a salt thereof; and (d) at least one member selected from the group consisting of vulcanizing agents and crosslinking agents:

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wherein R.sup.1 represents a hydrogen atom, an alkyl group, or an aralkyl group; R.sup.2, R.sup.3, and R.sup.4 are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group; and each of these groups optionally further has one or more substituents.

Process for producing a pressure-sensitive adhesive comprising expanded microballoons, wherein the constituents for forming the adhesive are mixed in a first mixing assembly, the mixed adhesive is transferred into a second mixing assembly into which, at the same time, unexpanded microballoons are fed, the microballoons are expanded in the second mixing assembly or on exit from the second mixing assembly, the adhesive mixture with the expanded microballoons is shaped to a layer in a shaping assembly in which expanded microballoons which have broken through the surface are pressed into the layer surface and the layer of adhesive mixture together with the expanded microballoons are optionally applied to a weblike backing material.

Provided is a rubber composition for tire treads containing a diene rubber, from 1 to 20 parts by weight of a silica containing millable silicone rubber compound, and from 0.2 to 20 parts by weight of thermally expandable microcapsules, per 100 parts by weight of the diene rubber. A rubber hardness of the millable silicone rubber compound is from 10 to 50.

According to the process for preparing a vulcanized rubber composition of the invention comprising (a) a step of preparing a master batch comprising a modified conjugated diene polymer and silica, (b) a step of preparing a master batch comprising an isoprene rubber and silica, (c) a step of kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step of vulcanizing a kneaded product obtained in (c), wherein the obtained vulcanized rubber composition comprises a phase A comprising a modified conjugated diene polymer and a phase B comprising an isoprene rubber, which are incompatible with each other, an abundance ratio of silica in the phase A satisfies 0.50.9 (Relation 1), and a proportion of the modified conjugated diene polymer satisfies 0.40.8 (Relation 2) it is possible to improve performance on ice and abrasion resistance and to provide a vulcanized rubber composition having excellent performance on ice and abrasion resistance, and a studless tire with a tread made using the same.

The invention relates to an alkoxysilane polysulfide, of formula (I):

(R.sup.3O).sub.3-n(R.sup.1).sub.nSiCH.sub.2(R.sup.2)CHZS.sub.xZHC(R.sup.2)CH.sub.2Si(R.sup.1).sub.n(OR.sup.3).sub.3-n(I),

in which: R.sup.1, which are identical or different, each represent a monovalent hydrocarbon group having from 1 to 18 carbon atoms; R.sup.2, which are identical or different, each represent a monovalent hydrocarbon group having from 1 to 4 carbon atoms; R.sup.3, which are identical or different, each represent a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably from 1 to 6 carbon atoms; Z, which are identical or different, each represent a divalent hydrocarbon bonding group comprising from 1 to 16 carbon atoms; x is an integral or fractional number greater than or equal to 2; and n is an integer equal to 0, 1 or 2.

Expanded rubber articles and processes for making such, comprising: partially curing an expandable rubber formulation by heating it in a first mould cavity to form a moulded blank; releasing the moulded blank from the first mould cavity and allowing the moulded blank to expand to form an expanded moulded blank; and further curing and expanding the expanded moulded blank by heating it to form the expanded rubber article comprising an expanded rubber part, wherein the expanded moulded blank is heated in a second mould cavity. Optionally, the expanded moulded blank is contacted with a further rubber formulation and a substrate comprising a base material and an elastomer bonding layer in the second mould cavity to form an expanded rubber article additionally comprising a solid rubber part and a substrate.

Blends of elastomer composites with unfilled or less highly filled elastomer reduces hysteresis without compromising reinforcement. Hysteresis may also be reduced by adjusting the compounding method.

Systems and methods for managing the waste associated with the extraction of rubber from guayule shrubs are provided. Also provided is a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber. Use of the disclosed systems, methods and/or local sub-station can reduce transportation costs, reduce processing costs and reduce the downstream processing complexity associated with the extraction of rubber from guayule shrubs.

An inventive electrically conductive rubber composition contains: a rubber component including SBR and/or NBR, and 20 to 30 parts by mass of epichlorohydrin rubber based on 100 parts by mass of the overall rubber component; a crosslinking component; a foaming component; and a potassium salt of an anion having a fluoro group and a sulfonyl group in its molecule, the potassium salt being present in a proportion of not less than 0.01 part by mass and not greater than 1 part by mass based on 100 parts by mass of the overall rubber component. An inventive transfer roller (1) includes a roller body (2) formed from the electrically conductive rubber composition.

An object of the present invention is to provide an expansion ratio improver for a polymer material that can impart an excellent expansion ratio to polymer materials. Another object of the present invention is to provide a resin composition for obtaining a foam having a high expansion ratio and fine (dense) cells. An expansion ratio improver for a polymer material, comprising at least one member selected from the group consisting of a pyrazolone-based compound and a salt of the compound. A resin composition comprising component (a): polyethylene, component (b): a chemical foaming agent, and component (c): a pyrazolone-based compound, the resin composition containing 0.1 parts by mass to 50 parts by mass of component (b) and 0.1 parts by mass to 50 parts by mass of component (c) based on 100 parts by mass of component (a).