Solid stabilizer composition for organic polymers, and process for preparing it

A stabilizing composition for organic polymers, composed of a solid continuous phase and another solid continuous phase dispersed in the former, characterized in that said former continuous phase consists of amorphous tetrakis-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyloxy-methyl]metha ne, and the dispersed phase is selected from among:

• (a) an either amorphous or crystalline organic phosphite, in the form of particles with a particle size comprised within the range of from 10 .mu.m to 2 mm, with said organic phosphite having a melting point higher than the melting point of said tetrakis-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyl-oxy-methyl]meth ane, and being selected from those definable by the general formula:
• ##STR4## wherein:
• R.sup.1, R.sup.2 and R.sup.3 represent either equal or different hydrocarbyl radicals, which can be alkyl, cycloalkyl, aryl, alkaryl or aralkyl radicals;
• the weight ratio of said continuous phase to said dispersed phase, in said composition, being furthermore comprised within the range of from 9:1 to 1:9, or
• (b) an either amorphous or crystalline organic phosphite, in the form of particles with a particle size comprised within the range of from 50 .mu.m to 2 mm, with said organic phosphite having a melting point higher than approximately 100.degree. C., and being selected from those definable by the general formulae:
• ##STR5## wherein:
• the R radicals independently represent alkyl, cycloalkyl, aryl, alkaryl or aralkyl radicals;
• the weight ratio of said continuous phase to said dispersed phase, in said compositions, being furthermore comprised within the range of from 9:1 to 1:9.