AQUEOUS COATING COMPOSITION COMPRISING POLYURETHANES AND VINYL POLYMERS

摘要

An aqueous coating composition comprising (i) a polyurethane obtained by the reaction of (a) an isocyanate-terminated pre-polymer obtained from the reaction of components comprising at least one polyisocyanate of which at least 50 wt % is at least one aliphatic polyisocyanate; in an NCO/OH ratio in the range of from 1.75 to 1.05; and (b) an active-hydrogen chain-extending compound; and (ii) a vinyl polymer having a Tg below ambient temperature.

主权项

1. An aqueous coating composition comprising:
(i) 50 to 95 wt % of a polyurethane obtained by the reaction of:
(a) an isocyanate-terminated pre-polymer obtained from the reaction of components comprising:
(1) 10 to 40 wt % of at least one polyisocyanate of which at least 50 wt % is at least one aliphatic polyisocyanate;(2) 0 to 10 wt % of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol, containing ionic or potentially ionic water-dispersing groups;(3) 50 to 89 wt % of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol;(4) 0 to 10 wt % of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol not comprised by (2);in an NCO/OH ratio in the range of from 1.75 to 1.05; andwhere (1), (2), (3) and (4) add up to 100%; and(b) an active-hydrogen chain-extending compound;and (ii) 5 to 50 wt % of a vinyl polymer having a Tg below ambient temperature; wherein (i) and (ii) add up to 100%; and (iii) a liquid medium comprising ≦10 wt % of organic solvent.