Patent ID: 11866538
Assignee: JIANGNAN UNIVERSITY
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  D | IPC C  D

Claim 0:
1. A method for preparing a polyurethane-acrylate water repellant, comprising:
(a) preparing a polyurethane prepolymer by using diisocyanate, a part of a hydrophilic chain extender and a polymer polyol;
(b) continuously reacting the polyurethane prepolymer with a double carbon-carbon double bond-containing dihydroxy micromolecular chain extender and the remaining hydrophilic chain extender for a period of time to obtain a waterborne polyurethane emulsion with carbon-carbon double bonds in the side chain, the double carbon-carbon double bond-containing dihydroxy micromolecular chain extender being a compound with the following formula (II);
(c) adding an oxime blocking agent to block an isocyanate radical (NCO %≤0.5%);
(d) cooling, and adding a neutralizer to adjust pH to 7 to 8.5;
(e) adding deionized water for emulsification to obtain a waterborne polyurethane emulsion with carbon-carbon double bonds in a side chain; and
(f) performing a free radical polymerization of the polyurethane emulsion with carbon-carbon double bonds in the side chain and an acrylate monomer under the condition of an initiator to obtain the polyurethane-acrylate water repellant,, wherein the polyurethane-acrylate water repellant comprises carbon-carbon double bonds introduced in a polyurethane side chain, and has the structure in formula (I):, and wherein:
R1 is an oxime blocking group;
R2 is derived from a diisocyanate monomer;
R3 is selected from alkyl, phenyl, a cyclic group, acyl, an ester group, carbonyl, and an ether group having any number of carbon atoms;
R4 is selected from alkyl, a cyclic group and its derivatives, and phenyl and its derivatives;
R5 is a carbon chain having 1 to 18 carbon atoms;
R6 is derived from polyether or polyol polyorganic compounds;
R7 is derived from a hydrophilic chain extender; and
a and n are natural numbers of 1 to 100.