Radiation curable aqueous composition for low gloss coatings

摘要

A radiation curable aqueous coating composition having a 85° gloss of ≦60 upon drying comprising (A) 10 to 99 wt % of a polyurethane, (B) 1 to 90 wt % of a radiation curable component; (C) 0.1 to 10 wt % of an associative thickener; wherein at least 80 wt % of (A)+(B)+(C) has a particle size greater than 500 nm and wherein the C═C bond concentration of the composition is 0.2 to 5.0 mmol per g of (A)+(B)+(C).

主权项

1. An ultraviolet (UV) radiation curable aqueous coating composition comprising:
(A) 10 to 99 wt % of a polyurethane obtained by the reaction of components comprising:
(i) 5 to 65 wt % of at least one organic polyisocyanate;(ii) 0.1 to 6 wt % of at least one polyol containing ionic or potentially ionic water-dispersing groups having a molecular weight in the range of from 100 up to 500 g/mol;(iii) 0 to 30 wt % of at least one isocyanate-reactive component containing water-dispersing groups and having a molecular weight in the range of from 500 to 6000 g/mol;(iv) 0 to 80 wt % of at least one isocyanate-reactive component containing radiation curable functional groups and having a molecular weight in the range of from 70 to 6000 g/mol;(v) 0 to 50 wt % of at least one component not comprised by (i), (ii), (iii), (iv) or (vi);(vi) 0 to 50 wt % of at least one active-hydrogen chain extending compound;where (i), (ii), (iii), (iv), (v) and (vi) add up to 100 wt %; andwhere the NCO:OH ratio is in the range of from 0.4:1.0 to 10.0:1.0; (B) 1 to 90 wt % of a radiation curable component carrying two or more radiation polymerizable ethylenically unsaturated bonds which are capable of crosslinking; and (C) 0.1 to 10 wt % of an associative thickener; wherein (A)+(B)+(C) add up to 100 wt %; and wherein at least 80 wt % of the polyurethane (A)+(B)+(C) has a particle size greater than 500 nm; and wherein the C═C bond concentration of the composition is 0.2 to 5.0 mmol per g of (A)+(B)+(C) and wherein crosslinking of the aqueous coating composition is initiated by UV radiation, and wherein the coating composition exhibits an 85° gloss of <60 upon curing in the absence of a flattening agent.