Hydroxyphenylalkyleneyl isocyanurate/pentaerythritol phosphite combinations as ultraviolet light stabilizers for polyolefins

Claim 1

As a stabilizer for polyolefin polymers subject to degradation when exposed to ultraviolet light, a combination consisting essentially of (1) a hydroxyphenylalkyleneyl isocyanurate of the formula ##STR15## wherein R' is a hydroxyphenylalkyleneyl radical of the formula ##STR16## where m is 1 to 4, r 1 is an alkyl radical having 1 to 18 carbon atoms and is positioned immediately adjacent to the hydroxyl group on the ring; r 2 , r 3 , and r 4 are hydrogen or an alkyl radical containing 1 to 18 carbon atoms; and R" and R'" are hydrogen, an alkyl radical containing 1 to 18 carbon atoms, or are the same as R', and (2) a pentaerythritol phosphite compound selected from the group consisting of (a) compounds of the formula ##STR17## wherein R is selected from the group consisting of an aliphatic group containing 1 to about 20 carbon atoms, a cycloalkyl radical containing 5 to about 8 carbon atoms in the ring, and an aryl, alkaryl, or aralkyl group of 6 to about 14 carbon atoms in the group, (b) compounds of the formula ##STR18## wherein R is defined as above, and wherein the said hydroxyphenylalkyleneyl isocyanurate compound is used in a weight ratio of about 10:1 to 1:10 to the pentaerythritol phosphite compound.