FIELD: polymer materials.
SUBSTANCE: invention provides a process for continuous in-bulk production of foamable vinylaromatic polymers, which comprises following steps: (i) charging into extruder vinylaromatic polymer jointly with (a) copolymer obtained via polymerization of one or more vinylaromatic monomers and 0.1-15 wt% α-alkylstyrene, and 0-10 wt% (b) compatible polymer having crystallinity below 10% and vitrification temperature (Tg) above 100°C, provided that at least one of (a) and (b) is present in reaction mixture; (ii) heating polymers to temperature superior to relative melting temperature; (iii) adding foaming agent to molten product before extrusion; and (iv) molding, through extrusion head, optionally foamable essentially spherical granules having average diameter within a range of 0.2 to 2 mm. There are also provided foamable vinylaromatic polymers with improved foamability and additionally including 0.05 to 29% of athermic and refracting materials as well as application of foamed products having density between 5 and 50 g/L.
EFFECT: speeded up foaming of foamable polymer granules without a collapse of resulting plastic foam.
5 cl, 1 tbl, 5 ex
