Aqueous polyurethane resin

1. An aqueous polyurethane resin having a Si atom content of 0.05 to 1.5% by weight in a polyurethane resin obtained by reacting compounds consisting of

an isocyanate group-terminated prepolymer which comprises 1 to 15% by weight of a polyoxyethylene group in a side chain branched from the main chain and has two or more isocyanate groups at an end of the main chain, and

a chain extender which consists of a compound having two or more active hydrogen groups reactive with the isocyanate group and an alkoxysilyl group, wherein

the isocyanate group-terminated prepolymer is obtained by reacting compounds from the group consisting of: a polyisocyanate, one or more non-ionic low molecular weight polyol, a macropolyol, and a compound represented by the following general formula (1), wherein the one or more non-ionic low molecular weight polyol is selected from the group consisting of ethylene glycol, propanediol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexandiol, neopentyl glycol, alkane diol comprising 7 to 22 carbon atoms, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexane dimethanol, alkane-1,2-diol comprising 17 to 20 carbon atoms, hydrogenated bisphenol-A, 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, bishydroxyethoxy benzene, xylene bishydroxyethylene terephthalate, glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolpropane, 2,2-bis(hydroxymethyl)-3-butanol, aliphatic triol comprising 8 to 24 carbon atoms, tetramethylolmethane, D-sorbitol, xylitol, D-mannitol and D-mannite, and

the compound having two or more active hydrogen groups and an alkoxysilyl group contained in the chain extender is a compound represented by the following general formula (2),

wherein R 1 and R 2 are the same or different from each other, and each represents an alkylene group of 1 to 4 carbon atoms; R 3 represents an aliphatic, alicyclic, or aralkyl hydrocarbon group of 6 to 13 carbon atoms; R 4 represents an alkyl group of 1 to 4 carbon atoms; and n represents an integer of 8 to 50,

wherein R 5 and R 6 are the same or different from each other, and each represents an alkyl group of 1 to 4 carbon atoms; R 7 and R 8 are the same or different from each other, and each represents an alkylene group of 1 to 4 carbon atoms; and m represents an integer of 1 to 3.

2. The aqueous polyurethane resin according to claim 1 , wherein the macropolyol is a polycarbonatediol.

3. The aqueous polyurethane resin according to claim 2 , wherein the polycarbonatediol is an amorphous polycarbonatediol.

4. The aqueous polyurethane resin according to claim 1 , wherein the polyisocyanate is an aliphatic polyisocyanate and/or an alicyclic polyisocyanate.

5. The aqueous polyurethane resin according to claim 4 , wherein the polyisocyanate is at least one kind selected from the group consisting of 4,4′-, 2,4′- or 2,2′-dicyclohexylmethane diisocyanate or mixtures thereof, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or mixtures thereof, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, and 2,5- or 2,6-bis(isocyanatomethyl)norbornane or mixtures thereof.

6. The aqueous polyurethane resin according to claim 1 , having a thermal solidification temperature of 40 to 90° C.

7. The aqueous polyurethane resin according to claim 1 , being used for production of artificial leather.