Patent Title: POLYOL PREMIX COMPOSITION FOR RIGID POLYURETHANE FOAMS

 Number/Link: WO2016/162362

Applicant/Assignee: Covestro

Publication date: 13-10-2016

“Gist”: Addition of dicarboxilic acid reduces cream time in amine catalyzed foams

Why it is interesting: A short cream time has advantages for rigid PU spray foam because it can reduce dripping of the material after application.  According to this invention the cream time of an amine-catalyzed, HFC-blown spray foam composition can -surprisingly-be reduced by addition of a dicarboxilic acid, preferably succinic or glutaric acid. The diacids are used in a ratio of about 2 equivalents acid to 1 equivalent of (free) amine. In the examples a clear reduction of cream time is shown compared to compositions with no diacid, a mono-acid or less than the required amount of diacid. However, all examples also contain some trimerization catalyst (2-hydroxypropyl trimethylammonium formate) next to the tert-amine catalyst (N,N-dimethylcyclohexylamine). It would be interesting to see an example without the trimerization catalyst i.m.o.

Succinic acid