Abstract: [Problem] An object of the present invention is to provide a foam including a thermoplastic resin and rubber as a main component, in which a micronized product of a cellulose fiber is uniformly dispersed, and uniformity and mechanical properties are excellent. [Solution] A foam includes a modified cellulose fiber (A) covalently bonded with a diene-based polymer, a thermoplastic resin and/or rubber (B), and a diene-based polymer (C) having a functional group capable of covalently bonding with a cellulose fiber, in which the fiber (A) is micronized, the fiber (A) has a content of 0.05 to 20% by mass, and the thermoplastic resin and/or rubber (B) has a glass transition point of ?130° C. to 120° C.

Abstract: [Problem] An object of the present invention is to provide a foam including a thermoplastic resin and rubber as a main component, in which a micronized product of a cellulose fiber is uniformly dispersed, and uniformity and mechanical properties are excellent. [Solution] A foam includes a modified cellulose fiber (A) covalently bonded with a diene-based polymer, a thermoplastic resin and/or rubber (B), and a diene-based polymer (C) having a functional group capable of covalently bonding with a cellulose fiber, in which the fiber (A) is micronized, the fiber (A) has a content of 0.05 to 20% by mass, and the thermoplastic resin and/or rubber (B) has a glass transition point of ?130° C. to 120° C.

Abstract: Provided are modified plant fibers suitable for addition to rubber; an additive for rubber comprising the modified plant fibers which can be micronized and dispersed easily and highly when adding to rubber; a method of preparing the additive for rubber; and a rubber composition comprising the additive for rubber. Modified plant fibers (A) in which plant fibers (a) and a modified synthetic rubber (B) are covalently bonded wherein the ratio of the modified synthetic rubber (B) relative to 100 parts by weight of the plant fibers (a) is 5 to 100 parts by weight. An additive for rubber comprising 20 to 75 weight % of the modified plant fibers (A) according to claim 1 and 25 to 80 weight % of a processing agent for rubber (C), wherein the number average molecular weight of the processing agent for rubber (C) is 400 to 60,000, and the glass transition point of the processing agent for rubber (C) is 100° C. or less, and wherein the additive for rubber includes plant fibers in the ratio of 10 to 65 weight %.

Abstract: Provided is a pneumatic tire including a sidewall that has a good balance of excellent handling stability, rolling resistance, and durability and further has excellent flex crack growth resistance. The sidewall is formed from a modified cellulose fiber-containing rubber composition that is allowed to simultaneously achieve excellent rigidity, excellent tensile properties, and low energy loss by improving the dispersibility of the cellulose fiber in rubber. The present invention relates to a pneumatic tire including a sidewall formed from a modified cellulose fiber-containing rubber composition, the modified cellulose fiber-containing rubber composition containing a modified cellulose fiber (A) obtained by adding a C15 or higher cyclic polybasic acid anhydride (a) containing a hydrophobic group to a cellulose fiber through esterification, a dispersing polymer (B) having a softening point of 135° C. or lower, and a rubber component (C).

Abstract: Provided are modified plant fibers suitable for addition to rubber; an additive for rubber comprising the modified plant fibers which can be micronized and dispersed easily and highly when adding to rubber; a method of preparing the additive for rubber; and a rubber composition comprising the additive for rubber. Modified plant fibers (A) in which plant fibers (a) and a modified synthetic rubber (B) are covalently bonded wherein the ratio of the modified synthetic rubber (B) relative to 100 parts by weight of the plant fibers (a) is 5 to 100 parts by weight. An additive for rubber comprising 20 to 75 weight % of the modified plant fibers (A) according to claim 1 and 25 to 80 weight % of a processing agent for rubber (C), wherein the number average molecular weight of the processing agent for rubber (C) is 400 to 60,000, and the glass transition point of the processing agent for rubber (C) is 100° C. or less, and wherein the additive for rubber includes plant fibers in the ratio of 10 to 65 weight %.

Abstract: Provided are a modified cellulose fiber-containing rubber composition and rubber composition for tires that are allowed to simultaneously achieve excellent rigidity, excellent tensile properties, and low energy loss by improving the dispersibility of the cellulose fiber in rubber, as well as a pneumatic tire formed from the rubber composition, having excellent handling stability, excellent rolling resistance properties, and excellent durability. The present invention relates to a modified cellulose fiber-containing rubber composition containing: a modified cellulose fiber (A) obtained by adding a C15 or higher cyclic polybasic acid anhydride (a) containing a hydrophobic group to a cellulose fiber through esterification; a dispersing polymer (B) having a softening point of 135° C. or lower; and a rubber component (C).

Abstract: Provided are a modified cellulose fiber-containing rubber composition and rubber composition for tires that are allowed to simultaneously achieve excellent rigidity, excellent tensile properties, and low energy loss by improving the dispersibility of the cellulose fiber in rubber, as well as a pneumatic tire formed from the rubber composition, having excellent handling stability, excellent rolling resistance properties, and excellent durability. The present invention relates to a modified cellulose fiber-containing rubber composition containing: a modified cellulose fiber (A) obtained by adding a C15 or higher cyclic polybasic acid anhydride (a) containing a hydrophobic group to a cellulose fiber through esterification; a dispersing polymer (B) having a softening point of 135° C. or lower; and a rubber component (C).

Abstract: Provided is a pneumatic tire including a sidewall that has a good balance of excellent handling stability, rolling resistance, and durability and further has excellent flex crack growth resistance. The sidewall is formed from a modified cellulose fiber-containing rubber composition that is allowed to simultaneously achieve excellent rigidity, excellent tensile properties, and low energy loss by improving the dispersibility of the cellulose fiber in rubber. The present invention relates to a pneumatic tire including a sidewall formed from a modified cellulose fiber-containing rubber composition, the modified cellulose fiber-containing rubber composition containing a modified cellulose fiber (A) obtained by adding a C15 or higher cyclic polybasic acid anhydride (a) containing a hydrophobic group to a cellulose fiber through esterification, a dispersing polymer (B) having a softening point of 135° C. or lower, and a rubber component (C).