METHOD FOR PRODUCTION OF DIELECTRIC COMPOSITION MATERIAL Russian patent published in 1994 - IPC

FIELD: processing of thermoplastic polymers. SUBSTANCE: method comprises the steps of immersing hollow microspheres in liquid, separating floating fraction, sorting it into size grades, determining average size, axial and hydrostatic strength of microsphere fractions, mixing said fractions to achieve required volume filling coefficient, and crushing polymeric material to particle size which satisfies the inequality where d_p, d_ms - average diameter of polymeric particles and microspheres, C_v - volume fraction of microspheres. Then microspheres are mixed with polymer when composition variation coefficient drops below 1% , the mixture charge is calculated, loaded into closed press-mold, heated up to 1.1-1.3 of polymer melting temperature, compacted by pressure growing at the rate of 0.05-10 MPa/min to doubled axial strength of microspheres during meeting movement of die and punch, kept at constant pressure for 3-10 min, after which pressure is raised to hydrostatic strength of microspheres and material is cooled under pressure. EFFECT: higher efficiency. 5 cl, 3 tbl