Coating expandable granular polystyrene with glyceryl fatty acid ester - using aq. dispersion contg. oxyethylate with specified min m.pt.

摘要

In the use of aq. dispersions based on glyceryl esters (I) of fatty acids with min. 12C for coating small expandable polystyrene granules, the dispersion also contains 10-50 wt.%, w.r.t. (I), of oxethylates (II) of the formula RO(C2H4O)nH (in which R is 10-22C (cyclo)alkyl, 10-22C aliphatic acyl or an alkylphenyl gp. with min. 8C in the alkyl chain. n is 15-60). (II) has a m.pt. of min. 40 deg.C. Low coating temps. can be used, so that the free running and sifting properties are not impaired. The coating lubricates the surface of the granules well and does not prevent the expanded granules welding together.