Additive for masticating natural rubber, mastication method, composition obtained thereof and pneumatic tire

摘要

An additive for masticating natural rubber comprising at least one compound selected from the group consisting of benzoic acids, naphthoic acids, dicarboxylic acids and compounds represented by Formula (IV): <CHEM> wherein m and n each represent an integer of 1 to 3; p represents an integer of 1 to 4; m + n + p = 6; X is O, NR<8> or (R<9>O)q; R<6> is a C1 &tilde& C24 alkyl, a C2 &tilde& C24 alkenyl, or a C6 &tilde& C24 aryl group; and R<7> is H, OH, an alkyl, alkenyl, or aryl group; R<8> is H or C1 &tilde& C24 alkyl group; R<9> is a C1 &tilde& C4 alkyl group; q is an integer of 1 to 5, a mastication method and a natural rubber composition each of which uses the additive, and a pneumatic tire using the natural rubber composition.