Method of hygienic faultless stabilization of the polyolefine against thermooxidation and photooxidation degradation

The present invention relates to a process for stabilizing polyolefins by means of which the resistance to thermooxidation and photooxidation aging is increased, the polyolefins stabilized according to the invention being wholesome.

The prior art method of stabilizing polyolefins against thermooxidative degradation and photooxidative degradation is accomplished by applying antioxidants derived from phenol derivatives, aromatic amines, phosphites. These substances are mostly harmful to health and cannot be used in contact with food. Polyolefins stabilized by these substances induce unwanted inflammatory processes when used as implants in contact with tissues of the organism. Some of these compounds have been found to be carcinogenic (e.g., uphenyl-beta-naphthylamine).

The above drawbacks are overcome by stabilizing the polyolefins according to the invention, which comprises applying 0.01 to 5% alpha-tocopherol, beta-tococerol, gamma-tocopherol, delta-tocopherol or a mixture thereof to the polyolefins.

The tocopherol-stabilized polyolefins have substantially greater resistance to thermo-oxidative degradation at both the technical and processing temperatures of these materials. They have a higher resistance to photooxidative degradation, which results in higher durability when exposed to tocopherol-stabilized polyPlefin under natural weather conditions. They are harmless to health. They can be used in contact with food. They do not induce adverse tissue responses when such stabilized polyolefins are used as implants in the body. On the contrary, they have a beneficial effect on healing processes.