Abstract: The present invention relates to fine particles in which desired magnetic particles are enclosed, the fine particles being easy to handle, having a large surface area, being resistant to settling, being compact, and having a functional group such as a carboxyl group on the particle surface. The fine particles include at least one type of polyolefin or polyolefin copolymer and at least one type of magnetic material, are substantially spherical particles having a density of 0.9 to 1.5 g/cc and an average particle size of 0.5 ?m to 1,000 ?m, and have a functional group on the particle surface.

Abstract: A thermoplastic composite composition comprisingI. about 95 to about 30 percent by weight of a thermoplastic material andIi. about 5 to about 70 percent by weight of a polyolefin composition comprisingA. about 15 to about 60 percent by weight of a polyolefin andB. about 85 to about 40 percent by weight of at least one reactive inorganic filler,Said reactive inorganic filler having been prepared by effecting reaction betweenA. an inorganic material substantially comprising at least one compound selected from the group consisting of metal carbonates, metal hydroxides and metal oxides, said metal being selected from the group consisting of beryllium, magnesium, calcium, strontium, barium, zinc, cadmium and aluminum, said compound having a number average particle diameter of from about 0.01 .mu.. to about 50 .mu.. and a maximum particle diameter of about 100 .mu.., andB.