COMPOSITIONS AND METHODS FOR PROTECTING ORGANIC POLYMERIC MATERIALS FROM DISCOLORATION DUE TO EXPOSURE TO UV-C LIGHT

Polymer compositions for making a stabilized polymeric articles that are resistant to discoloration upon exposure to UV-C light having: (i) an organic polymeric material; and (ii) a hindered phenol, organic phosphite, or a combination thereof, with the provisos that: (a) the OH group on the aromatic ring of the hindered phenol is flanked by two tertiary hydrocarbyl groups, and (b) the organic phosphite does not have any -OAr group linked directly to the P atom of the phosphite, wherein Ar represents an unsubstituted or substituted aryl group, are provided herein. Reduced discoloration is associated with the use of specific hindered phenols and the organic phosphites compared to other hindered phenols and organic phosphites, even in the absence of other polymer additives including UV absorbers, hindered amine light stabilizers (HALS), metal oxides and/or barium salts. Methods of reducing discoloration of an organic polymeric material upon exposure to UV-C light are also provided, wherein such methods include the step of adding to the organic polymeric material a stabilizing amount of hindered phenol, organic phosphite, or a combination thereof.