Patent EP-2113523-A2 (EP)
Inventor: SOMMER STEFAN DR
IPC: C09D175/16
Filed: 2009-04-17
Abstract: Radiation-hardenable coating system comprises an aqueous polyurethane dispersion, which comprises: (i) a polyurethane; and (ii) 0-40 wt.% of oligo(meth)acrylate having a double bond density or greater than 2 mol double bond/kg substance and by the effect of high energy radiation reacts with ethylenically unsaturated compounds under polymerization, where the coating system containing the mixture of (i) and (ii) exhibits a weight average molecular weight of greater than 50000-3000000 g/mol. Radiation-hardenable coating system comprises an aqueous polyurethane dispersion, which comprises: (i) a polyurethane (obtained by reacting (a) 40-80 wt.% of hydroxyl group-containing component (which comprises (a1) 10-80 wt.%, relative to the sum of components (a)-(f) and (ii), of one or more hydroxyl group-containing prepolymer consisting of polyester- or polyether(meth)acrylate having an hydroxyl-number of 5-300 mg potassium hydroxide (KOH)/g substance and contains a group, which reacts (under the effect of high energy radiation) with ethylenically unsaturated double bonds under polymerization, and (a2) 0-50 wt.%, relative to the sum of components (a)-(f) and (ii), of one or more monomeric (meth)acrylate group-containing alcohols with a hydroxyl number of 35-1000 mg KOH/g substance), (b) 0.1-20 wt.% of one or more compounds that are reactive against isocyanate group and the compounds contain non-ionic group, ionic group or groups (Z) that are capable for formation of ionic groups, where (Z) is effective for dispersing the polyurethane dispersion, (c) 0.1-30 wt.% of a hydroxyl- and/or amine-containing component (which comprises (c1) 0.1-10 wt.%, relative to the sum of components (a)-(f) and (ii), of hydroxyl- and/or amine-functional monomer compound having a functionality of 3-6 and a molecular weight of 92-254 g/mol and/or (c2) 0.1-20 wt.%, relative to the sum of the components (a)-(f) and (ii), of hydroxyl- and/or amine functional polyesters, C 2-, C 3- and/or C 4-polyether or polyether ester having a functionality of 2.3-4 and a molecular weight of 238-4000 g/mol), (d) 0-30 wt.% of hydroxyl functional compounds consisting of group of monoalcohol and/or diol, each with a molecular weight of 32-118 g/mol, polyester, polycarbonate, C 2-, C 3- and/or C 4-polyether, polyether ester or polycarbonate polyester having a functionality of 1-2 and each has a molecular weight of 300-4000 g/mol, and (e) 0.1-10 wt.% of mono-, diamines and/or difunctional amino alcohols with (f) 10-50 wt.% of one or more polyisocyanate, where the use of polyepoxy(meth)acrylate during the synthesis of (I) is excluded); and (ii) 0-40 wt.% of oligo(meth)acrylate consisting of the groups in the component (a1) having a double bond density or greater than 2 mol double bond/kg substance and by the effect of high energy radiation reacts with ethylenically unsaturated compounds under polymerization, where the sum of the components (a)-(f) and component (ii) makes up to 100 wt.% and the coating system containing the mixture of (i) and (ii) exhibits a weight average molecular weight of greater than 50000-3000000 g/mol. Independent claims are included for: (1) a method for preparing the coating system comprising (aa1) reacting the components (a) to (d) with component (f) to form polyurethane prepolymer, (aa2) adding the component (ii), and (aa3) dispersing the obtained mixture in water to give aqueous polyurethane dispersion, where at least partial neutralization is carried out with component (b) (before, during or after the addition of the component (ii)/dispersion) to optionally introduce (potential) ionic groups, where a reaction of the polyurethane prepolymer with component (e) can be carried out at any time after the step (aa1); (2) adhesives or lacquers comprising the coating system; and (3) a substrate coated with lacquer obtained by using the coating system.