Process for the preparation of aqueous polyurethane dispersions, containing from 20 to 50% by weight of an anionic polyurethane having a mean particle size from 1 to 15 micron and providing films with durable low gloss aspect.

The present invention relates to a coating composition, a coating system comprising the coating composition, a coating method and application of the coating system, and a product coated with the coating system. The coating composition comprises: (A) at least one aqueous polyurethane dispersion and/or one aqueous polyacrylate dispersion, wherein the aqueous polyurethane dispersion comprises at least one polyurethane polymer (a), wherein the polyurethane polymer (a) is obtained by a reaction comprising at least one polyurethane prepolymer (a1) and at least one isocyanate-reactive component (a2), wherein the polyurethane prepolymer (a1) is obtained by a reaction comprising the following components: (a1-1) at least one polyisocyanate having an isocyanate functionality of no less than 2, and (a1-2) at least one polyfunctional polyether polyol having a hydroxyl functionality of no less than 3, wherein the polyfunctional polyether polyol has an amount of 1 wt % to 20 wt %, based on the amount of the components for preparing the polyurethane prepolymer being 100 wt %, and (B) at least one crosslinking agent.

The problem addressed by the present invention is to provide an antifogging coating film having excellent antifogging property, antifogging persistence, persistence of appearance, and elution resistance. The coating film according to the present invention contains a metal oxide (A) and a hydrophilic compound (B); the height of the eluate by a coating film surface elution test is 1.0 μm or less; this test is carried out by placing 10 μL of deionized water on the coating film, allowing the film to stand for 24 hours in a 23° C., 50% RH environment, measuring the eluate height of 20 locations selected randomly within a 10 cm.sup.2 range on the coating film surface, and determining the maximum height; and the water contact angle measured after subjecting the coating film to a moisture resistance test by exposure for 24 hours in an 85° C., 85% RH environment followed by standing for one hour in a 23° C., 50% RH environment, is less than 40°. Preferably, the elution level per coating film unit volume by a coating film total elution test is 40 mg/cm.sup.3 or less, and this test is carried out by immersing the coating film in 23° C. deionized water for 24 hours, then measuring the weight of the coating film eluate recovered from the deionized water.

A waterborne resin crosslinking agent is provided, wherein the waterborne resin crosslinking agent of the present invention includes a polycarbodiimide compound (A) and a polycarbodiimide compound (B); the polycarbodiimide compound (A) has a structure in which the isocyanate groups at both terminals are each capped with a predetermined hydrophilic organic compound; the polycarbodiimide compound (B) has a chain diisocyanate compound as a structural unit, and has a structure in which the isocyanate groups at both terminals are each capped with a predetermined organic compound, and the polycarbodiimide compound (A) is in an amount of 5 to 90 parts by mass per 100 parts by mass in total of the polycarbodiimide compounds (A) and (B).

Provided is a waterborne resin crosslinking agent, as well as a waterborne resin crosslinking agent-containing liquid and a waterborne resin composition, including the waterborne resin crosslinking agent. The waterborne resin crosslinking agent of the present invention includes a polycarbodiimide compound (A) and a polycarbodiimide compound (B); the polycarbodiimide compound (A) has a structure in which the isocyanate groups at both terminals are each capped with a predetermined hydrophilic organic compound; the polycarbodiimide compound (B) has, as a structural unit, a diisocyanate compound having one cyclohexyl ring or one benzene ring, and has a structure in which the isocyanate groups at both terminals are each capped with a predetermined organic compound, and the polycarbodiimide compound (A) is in an amount of 5 to 90 parts by mass per 100 parts by mass in total of the polycarbodiimide compounds (A) and (B).

A water-dispersible polyisocyanate contains an isocyanate group and a sulfone group. The water-dispersible polyisocyanate contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component contains a first polyisocyanate containing pentamethylene diisocyanate and a second polyisocyanate containing polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component contains a sulfone group-containing active hydrogen compound. The first polyisocyanate is contained in an amount of 40% by mass or more and 90% by mass or less relative to the total amount of the first polyisocyanate and the second polyisocyanate.

A thin self-supporting adhesive film is claimed that includes a first polyurethane and a solid surface-deactivated isocyanate.

Described herein is a composition including at least one polyurethane polymer. Also described herein are a method of using the composition including at least one polyurethane polymer for metal pre-treatment and a process for metal pre-treatment.

A process for producing a water-emulsifiable polyisocyanate formulation, in which, in a first process step,

(A) a dispersion-active reaction product (E) is prepared from at least one diisocyanate selected from the group of hexamethylene 1,6-diisocyanate, pentamethylene 1,5-diisocyanate, 4,4′-di(isocyanatocyclohexyl)methane, 1-isocyanato-3,3,5-trimethyl-5-(isocyanatomethyl)cyclohexane, tolylene 2,4- and 2,6-diisocyanate, tetramethylxylylene diisocyanate, p-xylylene diisocyanate, 2,4′- and 4,4′-diisocyanatodiphenylmethane, with at least one mono- or polyhydric polyalkylene ether alcohol having 2 to 4 carbon atoms in the alkylene groups that comprises a polymer chain having at least 8 ethylene oxide units, and the resultant reaction product (E), in a second process step,
(B) is mixed with at least one (cyclo)aliphatic polyisocyanate having an average NCO functionality of 2.2 to 5.0, preferably of 2.5 to 4.0,
wherein step (B) is performed in the presence of an allophanatization catalyst and the conditions are chosen such that (E) and the polyisocyanate form allophanate groups, characterized in that the allophanatization catalyst is at least one salt consisting of a metal cation and at least one dithiophosphate anion.

The present invention relates to an aqueous coating composition comprising polyurethane A and vinyl polymer, wherein the polyurethane A comprises as building blocks at least: (a) a polyisocyanate(s) containing at least two cyclic groups, (b) a non-cyclic aliphatic diisocyanate(s) whereby the non-cyclic aliphatic group connecting the two isocyanate groups has from 4 to 36 carbon atoms, and (c) a component(s) containing an isocyanate-reactive group(s), whereby the summed amount of (a) and (b) is 10 to 60 wt. %, relative to the total weight amount of components used to prepare the polyurethane A; and whereby the weight ratio between (a) and (b) is in the range from 50:50 to 99:1.