Piperidine derivatives and their use as stabilizers

A synthetic polymer composition stabilized against photo- and thermal-deterioration wherein there is incorporated, in a sufficient amount to prevent said deterioration, at least one compound selected from the group consisting of the compounds having the formula ##SPC22##

• wherein
• R' represents an alkylene group which may be interrupted with an oxygen or sulfur atom, an alkenylene group, an alkynylene group, an aralkylene group, an aliphatic diacyl group, a group of the formula ##EQU13## in which n is an integer of 1 or 2 and X is an alkylene group, or o-, m- or p-phenylene group or the carbon atoms of CO groups may be directly joined in the absence of X or a group of the formula ##EQU14## in which Y is an alkylene group or o-, m- or p-phenylene group;
• and R represents hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, an alkoxycarbonylalkenyl group, an aliphatic, aromatic or heterocyclic monoacyl group, a N-substituted carbamoyl group, a N-substituted thiocarbamoyl group or a monovalent radical derived from an oxoacid, the compounds having the formula ##SPC23##
• wherein
• R' represents an alkylene group which may be interrupted with an oxygen or sulfur atom, an alkenylene group, an alkynylene group, an aralkylene group, an aliphatic diacyl group, a group of the formula ##EQU15## in which n is an integer of 1 or 2 and X is an alkylene group, or o-, m- or p-phenylene group or the carbon atoms of CO groups may be directly joined in the absence of X or a group of the formula ##EQU16## in which Y is an alkylene group or o-, m- or p-phenylene group;
• R.sub.1 and R.sub.2 individually represent a lower alkyl group or they jointly represent, together with the oxygen atoms, a group of the formula ##SPC24##
• in which R.sub.3 is hydrogen atom, a lower alkyl group or hydroxymethyl or a group of the formula ##SPC25##
• in which R.sub.4 and R.sub.5 may be the same or different and each represents hydrogen atom, a lower alkyl group or hydroxymethyl group and R.sub.6 is hydrogen or a lower alkyl group, the compounds having the formula ##SPC26##
• wherein
• R' represents an alkylene group which may be interrupted with an oxygen or sulfur atom, an alkenylene group, an alkynylene group, an aralkylene group, an aliphatic diacyl group, a group of the formula ##EQU17## in which n is an integer of 1 or 2 and X is an alkylene group, or o-, m- or p-phenylene group or the carbon atoms of CO groups may be directly joined in the absence of X or a group of the formula ##EQU18## in which Y is an alkylene group or o-, m- or p-phenylene group;
• and R.sub.7 represents an alkyl group or an aralkyl group, and the compounds having the formula ##SPC27##
• wherein
• R' represents an alkylene group which may be interrupted with an oxygen or sulfur atom, an alkenylene group, an alkynylene group, an aralkylene group, an aliphatic diacyl group, a group of the formula ##EQU19## in which n is an integer of 1 or 2 and X is an alkylene group, or o-, m- or p-phenylene group or the carbon atoms of CO groups may be directly joined in the absence of X or a group of the formula ##EQU20## in which Y is an alkylene group or o-, m- or p- phenylene group.