Patent ID: 7799951

Claim:
A process for preventing contact discoloration of substrates coming into contact with elastomers and stabilizing elastomers to prevent oxidative, thermal, dynamic, light -induced and/or ozone-induced degradation, which comprises incorporating into the elastomers, or applying to these, a mixture comprising a) at least a compound of formula I wherein R 1 is C 1 -C 12 alkyl, R 2 is C 1 -C 12 alkyl, or R 1 and R 2 together with the carbon atom to which they are attached form an unsubstituted or C 1 -C 4 alkyl substituted C 5 -C 12 cycloalkyl ring; R 3 is hydrogen, R 4 is an unsubstituted or cyano substituted C 5 -C 18 -alkyl; C 7 -C 9 phenylalkyl, unsubstituted or halogen, hydroxyl, cyano or C 1 -C 4 alkyl substituted phenyl or naphthyl; benzothiazolyl or —R 6 —CO 2 —R 7 , R 6 is C 1 -C 18 alkylene, R 7 is C 1 -C 18 alkyl, and m is 0, 1 or 2; and b) at least a compound of formula I wherein R 1 is C 1 -C 12 alkyl, R 2 is C 1 -C 12 alkyl, or R 1 and R 2 together with the carbon atom to which they are attached form an unsubstituted or C 1 -C 4 alkyl substituted C 5 -C 12 cycloalkyl ring; R 3 is —CH 2 —S(O) m —R 5 , R 4 and R 5 independently of each other are unsubstituted or cyano substituted C 5 -C 18 alkyl; C 7 -C 9 phenylalkyl, unsubstituted or halogen, hydroxyl, cyano or C 1 -C 4 alkyl substituted phenyl or naphthyl; benzothiazolyl or —R 6 —CO 2 —R 7 , R 6 is C 1 -C 18 alkylene, R 7 is C 1 -C 18 alkyl, and m is 0, 1 or 2.