| 摘要 |
<p>Process for the preparation of master batches of additives for compositions on the bases of polymers, as flame-retardant agents, stabilizers, oxidation inhibitors, dyes, pigments, antistatic additives, inert and/or reinforcing fillers and the like, of the type providing the coating and/or the blending of said additives (previously micronized) with inert and compacting substances, which process comprises the mixing, in at least two successive mixing steps, of at least one of said additives, previously micronized, with at least one molten wax, said wax having a melting point comprised within the range of approximately from 40oC to 160oC, and being moreover of such a nature as to result compatible both with said additives, and with polymers comprised in the polymeric composition into which the same additives are destined to be added as master batch, the first one of said mixing steps performing the function of accomplishing a thin film of wax wetting around the individual particles of said additives, and the further mixing step(s) performing the function of first accomplishing the aggregation of the wax-coated particles, as obtained above, as spheroidal particles of about 20 to 2000 νm in diameter, and of then accomplishing the stabilization of these latter particles into other end spheroidal particles of about 100 to 3000 νm in diameter, said end particles resulting free-flowing and dust-free. The master batches are characterized by very high concentrations of said additives (80-95%) and by being hygienically safe in the operations they are handled in.</p> |
