| abstract |
An aqueous coating composition comprising: (i) (10) to (80) wt % of a polyurethane A which exhibits a minimum film forming temperature of ≦ambient temperature and which comprises a polyurethane obtained by the reaction of: (a) an isocyanate-terminated pre-polymer formed from components which comprise: (1) 10 to 30 wt % of a polyisocyanate; (2) 0.1 to 10 wt % of a polyol of weight average molecular weight less than 500, containing ionic or potentially ionic water-dispersing groups, and having two or more isocyanate-reactive groups; (3) 0 to 15 wt % of a polyol containing non-ionic water dispersing groups having two or more isocyanate-reactive groups; (4) 40 to 80 wt % of a polyol other than (2) or (3), having two or more isocyanate-reactive groups; where (1), (2), (3) and (4) add up to 100%; and (b) an active-hydrogen chain extending compound; and (ii) 20 to 90 wt % of a polymer dispersion B which exhibits a minimum film forming temperature of above ambient temperature; wherein (i) and (ii) add up to 100%. Processes for manufacture of said composition and methods of application to substrates are also described. |