ADDITIVE FOR MASTICATION OF NATURAL RUBBER, MASTICATION METHOD OF NATURAL RUBBER, NATURAL RUBBER COMPOSITION OBTAINED BY SAID MASTICATION AND TIRE USING SAID COMPOSITION

摘要

PROBLEM TO BE SOLVED: To decrease a gel content and improve processability without reduction of molecular weight of a natural rubber by adding a specific additive for mastication of a natural rubber to the natural rubber and masticating thereof. SOLUTION: 100 pts.wt. of a natural rubber is masticated using 0.05-20 pts.wt. of at least one additive for mastication of a natural rubber selected from aromatic polycarboxylic acid derivatives represented by the formula (wherein m and n are each 1-3; p is 1-4 and m+n+p is 6; in case of m=2, a part or all of the carboxyl groups may be dehydrated in a molecule; X is O, NR3 or (R4 O)q; R3 is H or an 1-4C alkyl; R4 is an 1-4C alkyl; q is 1-5; R1 is an 1-24C alkyl, alkenyl or aryl; and R2 is H, OH, alkyl, alkenyl or aryl and a part or all of H of R1 and R2 may be substituted by a halogen) at 60-85 deg.C, preferably 70-80 deg.C for 60-120 seconds, preferably 80-100 seconds.