Harder for water-soluble epoxy resin system with peak time display

摘要

A water-dispersible hardener (I) for epoxy resins, indicates the end of the working time by means of a marked increase in viscosity. Hardener (I) contains reaction products (ABC) of adducts (AB), derived from (A) aliphatic polyols with a weight-average molecular weight (Mw) of 200-20000 and (B) epoxide(s) with at least two epoxide groups and epoxide group contents of 500-10000 mmols/kg, with (C) polyamines with at least 3 amine hydrogen atoms and at least one primary amino group, optionally followed by chemical modification of ABC. In one version (1), component (AB) contains (i) a mixture of at least 1 wt% adducts (A2B) of epoxides (B) with aliphatic polyols (A2) with Mw = at least 4000 and up to 99 wt.% adducts (A1B) of epoxides (B) with aliphatic polyols (A1) with Mw = less than 4000. In another version (2), (AB) contains adducts of a polyol mixture (A) comprising at least 1 wt.% polyols (A2) as above and up to 99 wt.% polyols (A1) as above with epoxides (B). In the synthesis of adducts (AB), (A1B) and (A2B), the ratio of the number of hydroxyl groups in the polyol to the number of epoxide groups in (B) = (1:3)-(1:10), and the ratio of the number of residual epoxide groups in adducts (AB) to the number of amine H atoms in (C) = (1:1.5)-(1:100). Also claimed are processes for the production of (I).