Degradation by the action of heat and light is a major problem in the use of vinyl halide resins. Various additives have been proposed as stabilizers to offset the deleterious effects of heat and light in the manufacture of useful articles from such resins. The problem has been compounded in recent times by the numerous governmental regulations designed to safeguard the environment and to reduce or eliminate potential hazards to the well being of the populace.
The emphasis on environmental quality and the increasing awareness of toxicological requirements have led the plastics industry, and in particular the vinyl halide resin field, to seek a satisfactory replacement for the high performance stabilizers based upon the compounds of the heavy metals, such as cadmium, barium, lead, etc., currently in wide usage in the industry.
The use of calcium and zinc salts of higher fatty acids for the stabilization of vinyl halides is well recognized in the art. However, these salts, and similar salts of magnesium and tin, do not provide the same degree of effectiveness as the salts of barium and cadmium. It is, therefore, clearly a desirable objective to increase the effectiveness of the stabilizers based upon calcium and zinc, and thereby provide an effective replacement for the lead, barium and cadmium based stabilizers.
USPTO Backgrounds
USPTO Backgrounds