Patent ID: 8461351

Claim:
A sterically bulky stabilizer of the formula: wherein each of R a and R b independently represent H or substituted or unsubstituted alkyl groups, provided that at least one of R a and R b on each benzimidazolone group represents H, and R c represents a group selected from the group consisting of: —X—(CH 2 ) n X—; —[(XCH 2 CH 2 ) n ]X—; —[(C═O)—(CH 2 ) n — (C═O)]—; —X—[(C═O)—(CH 2 ) n —(C═O)]—X—; —X—[(C═O)—X—(CH 2 ) n —X—(C═O)]—X—; —[(C═O)—X—(CH 2 ) n —X—(C═O)]—; wherein X, X 1 , and X 2 independently represent O, S, or NH, and n is an integer of 1 to 50.