Patent ID: 7572850

Claim:
A cushion gum having improved storage stability, the cushion gum comprising: rubber selected from the group consisting of polybutadienes (BR), polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers, butadiene-styrene copolymers (SBR), butadiene-isoprene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR) and mixtures thereof; an ultra-accelerator; and between 3 and 10 phr (parts per hundred of the rubber by weight) of a compound R1—NH-phenyl-NH—R2, wherein the amino moieties occupy the 1 and 4 positions of the phenyl ring, and R1 and R2 are selected from the group consisting of H, C1 to C3 straight chain or branched alkyl groups, C4 to C5 straight chain or branched alkyl groups and C6 to C15 straight chain or branched alkyl groups; wherein if R1 and R2 are branched alkyl groups, the branched groups are methyl groups, ethyl groups or combinations thereof, and wherein R1 and R2 may be the same or different; and wherein the increased storage stability is evidenced by the t 90 isothermal at 125° C., after 28 days aging at 40° C., being within thirty percent of the t 90 isothermal of the unaged composition.