Stabilization systems from triarylphosphites and phenols
AssigneeCiba-Geigy Corporation
InventorsHorst Zinke, Hans J. Lorenz, Helmut Linhart
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Abstract
Stabilization system consisting of a triarylphosphite of the general formula ##STR1## wherein R.sub.1 represents tert.-butyl, 1,1-dimethylpropyl, cyclohexyl or phenyl, and one of R.sub.2 and R.sub.3 is hydrogen and the other is hydrogen, methyl, tert.-butyl, 1,1-dimethylpropyl, cyclohexyl or phenyl, and a phenolic antioxidant, for stabilizing polyolefins.
Claims20
A stabilized composition consisting essentially of
- (a) a polymer that is derived from a singly unsaturated acyclic hydrocarbon, or mixtures or copolymers thereof and
- (b) from 0.005 to 5% of a mixture of
- (1) a triarylphosphite of the general formula ##STR4## wherein R.sub.1 represents tert-butyl, or 1,1-dimethylpropyl,
- R.sub.2 represents methyl, tert-butyl, or 1,1-dimethylpropyl, and
- (2) a hindered phenolic antioxidant selected from the group consisting of 1,3,5-tris-(3',5'-di-t.butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris-(3,5-di-t.butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, ethyleneglycol-bis(3,3-bis-3'-t.butyl-4'-hydroxyphenyl)-butyrate, pentaerylthrit-tetra-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate], thiobisethyleneglycol-bis-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate], hexamethylene-1,6-di-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate] and .beta.-(3,5-di-t.butyl-4-hydroxyphenyl)-propionic acid-n-octadecyl ester, the ratio of the phosphite to the antioxidant being from 10:1 to 1:5.
A composition claim of 1, wherein the triarylphosphite is tris-(2,4-di-tert-butylphenyl)phosphite.
A method of stabilizing polymers derived from singly unsaturated, acyclic hydrocarbons or mixtures or copolymers thereof during processing which comprises incorporating in said polymer 0.005 to 5% of a mixture consisting essentially of
- (a) a triarylphosphite of the general formula ##STR5## wherein R.sub.1 represents tert-butyl, or 1,1-dimethylpropyl;
- R.sub.2 represents methyl, tert-butyl, or 1,1-dimethylpropyl, and
- (b) hindered phenolic antioxidant selected from the group consisting of 1,3,5-tris-(3',5'-di-t.butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris-(3,5-di-t.butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, ethyleneglycol-bis(3,3-bis-3'-t.butyl-4'-hydroxyphenyl)-butyrate, pentaerylthrit-tetra-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate], thiobisethyleneglycol-bis-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate], hexamethylene-1,6-di-[3-(3,5-di-t.butyl-4-hydroxyphenyl)-propionate] and .beta.-(3,5-di-t.butyl-4-hydroxyphenyl)-propionic acid-n-octadecyl ester, wherein the phosphite to the antioxidant ratio is 10:1 to 1:5.
Dependencies are inferred from the claim text.