Thermoplastic compositions with very high content of pulverulent mineral materials for incorporation into polymers

Claim 1

A coherent thermoplastic aggregate with very high content of pulverulent mineral materials comprising: (a) 19.99 to 4.05 wt. % of at least one polyolefin polymer or copolymer having a fusion or softening temperature of at least 60° C. and an index of fluidity of at least 50, wherein said polyolefin polymer or copolymer is selected from the group consisting of linear or branched low density polyethylenes; high density polyethylenes; polypropylene homopolymers; polyisobutylenes; copolymers obtained by copolymerization of at least two monomers selected from the group consisting of ethylene, propylene, and isobutylene; halogenated polyolefins, and polypropylene modified by grafting or copolymerization with EPDM or SEBS, (b) 80-95 wt. % of a pulverulent mineral material, present in an amount of 400 to 1900 parts by weight per 100 parts by weight of the said polyolefin polymer or copolymer, said pulverulent mineral material having a particular size distribution such that 95% of the particles have at least one dimension <30 microns; and (c) as a fluidifacient agent in an amount of 0.01 to 0.95 wt. % of a phosphate having the following formula: ##STR2## where A represents ethylene oxide; B represents propylene oxide; 0≦(m+n)≦24; R represents a linear or nonlinear alkyl group which may be saturated or unsaturated, an aryl group, a saturated or unsaturated heterocycle, wherewith said alkyl, aryl, or heterocycle has 5-28 C atoms, or R is a steroid group; and R' is hydrogen, a carbon chain having 1-4 C atoms, or a group R as defined above; and wherein said aggregate has a density near to the theoretical density of said pulverulent mineral material while still providing excellent compatibility with said polymer or copolymer, and wherein the interparticle voids between the grains of said mineral material are filled by at least one said polymer or copolymer.