Expandable styrene polymer (PS), esp for recycling PS foam particles - contains PS, fire retardants in the body of the polymer and on the surface of the particles, low-boiling blowing agent and opt additives

摘要

Fine-particle, expandable styrene polymers (I) are claimed, contg. (a) 95-99.8 wt.% polystyrene and/or a copolymer contg. at least 50 wt.% styrene (PS), (b) 0.2-5 wt.% fire retardant(s), 0.1-2.5 wt.% of which is homogeneously distributed in the polymer and 0.1-2.5 wt.% of which is present as a surface coating, (c) 2-10 wt.% low-boiling blowing agent (all w.r.t. a+b) and opt. (d) conventional additives. Also claimed are (i) a process for recycling PS foam particles (II), by mixing pulverised (II) with fine-particles, pre-expanded (I) and bonding the mixt. in a mould to give foam mouldings; and (ii) foam of density 0.01-0.2 g/cm3, obtd. by this process. USE/ADVANTAGE - The invention enables the prodn. of self-extinguishing expanded foam (EPS) prods. from mixts. contg. a large proportion of non-fire-resistant, recycled E