摘要 |
Expandable granulates, having compositions based on vinyl-aromatic polymers, including: a) 65-99.8% by weight of a copolymer obtained by polymerizing 85-100% by weight of one or more vinyl-aromatic monomers and 0-15% by weight of an α-alkylstyrene in which the alkyl group contains from 1 to 4 carbon atoms; b) 0.01-20% by weight, calculated with respect to the polymer (a), of a carbon black having an average diameter ranging from 10 to 1000 nm and a surface area ranging from 5 to 200 m2/g; c) 0.01-5% by weight, calculated with respect to the polymer (a), of c1) oxides and sulfates and lamellar dichalcogenides of metals; or c2) oxides and sulfates of metals, or c3) lamellar dichalcogenides of metals; or c4) oxides of metals; or c5) sulfates and lamellar dichalcogenides of metals; or c6) sulfates of metals; d) at least one of the following additives d1) and d2): d1) 0.01-5% by weight, calculated with respect to the polymer (a), of graphite having an average diameter ranging from 0.5 to 50 μm; d2) 0.01-5% by weight, calculated with respect to the polymer (a), of inorganic derivatives of silicon of the lamellar type; e) 0-5% by weight, calculated with respect to the polymer (a), of a nucleating agent; and f) 1-6% by weight, calculated with respect to 100 parts of the total of (a)-(e), of one or more expanding agents. |