Isocyanurate Gp.-contg. poly-isocyanate mixts. for PU foam prodn. - by partial trimerisation of mixt. of specified amts. of 4,4-, 2,4- and 2,2-MDI isomers contg. 0-20 wt. per cent higher poly-isocyanate(s)

摘要

Liq. isocyanurate gp.-contg. polyisocyanate mixts. with NCO content 15-30 wt. % (I) are claimed. (I) are obtd. by partial trimerisation of the NCO gps. in polyisocyanate mixts. of the diphenylmethane series (II) contg. 80-100 wt. % MDI isomers (IIA) and 0-20 wt. % higher than difunctional polyisocyanates (IIB) in which (IIA) contains 40-80 wt. % 4,4'-MDI, 20-60 wt. % 2,4'-MDO and 0-8 wt. % 2-2'-MDI. - Also claimed is a process for the prodn. of (I) by trimerisation of mixts. (II) opt. with addn. of OH gp. contg. components in the presence of a trimerisation catalyst (III) to obtain the required deg. of trimerisation and then stopping the reaction with a catalyst poison. - Pref. 0-50 wt. % of the reacted NCO gps. in (I) have been converted into urethane gps.