Stabilising method of polymers to u.v.radiation

1332560 2 - (2 - Hydroxyphenyl)benzimidazoles CIBA-GEIGY AG 17 June 1971 [19 June 1970] 28490/71 Heading C2C [Also in Division C3] The invention comprises compounds (I) where one of X 1 and X 2 is C 3-14 sec-alkyl or 1- phenethyl and the other is C 1-14 alkyl, benzyl, 1-phenethyl, cycloehxyl, cyclo-octyl or chlorine, one of X 2 may also be hydrogen and R 1 is hydrogen, chlorine, methyl or methoxy with the proviso that X 1 is not 1-phenylethyl or benzyl when R 1 and X 2 are hydrogen which may be made in known manner from an appropriate 2- nitroaniline by diazotization, coupling with a phenol and reducing the resulting 2-nitroazo compound with zinc in alkaline solution. The compounds of the invention are useful as U.V.-absorbers for addition to polymeric substrates.