Process for making crosslinkable polyurethane/acrylic hybrid dispersions

Patent metadata

Field	Value
Publication number	US-2016009944-A1
Application number	US-201514858346-A
Country	US
Kind code	A1
Filing date	Sep 18, 2015
Priority date	Dec 22, 2011
Publication date	Jan 14, 2016
Grant date	—

Abstract

The present invention provides a new process of preparation for PUA with superior mechanical performance, such as elongation, and tensile strength. The process is solvent free, smooth, and robust. PU prepolymer prepared according to the present invention has low viscosity, and contains no particulate DMPA.

First claim

1 - 7 . (canceled)

8 . A polyurethane/acrylic hybrid dispersion prepared according to a process comprising the following continuous steps:
i) adding at least one polyol into a reactor; ii) adding dimethylolpropionic acid (DMPA) simultaneously with step i), or after step i) but before step iii), as a water dispersibility enhancing agent at a temperature of from 115° C. to 140° C. to obtain a homogeneous solution; iii) adding at least one polyisocyanate at a temperature of from 75° C. to 95° C. and stirring until NCO content reaches a constant value to prepare a polyurethane prepolymer; iv) adding at least one acrylate monomer, at least one styrenic monomer, or a mixture thereof, as a diluent to the polyurethane prepolymer, at a temperature of from 40° C. to 65° C.; v) adding a neutralizing agent; vi) dispersing the polyurethane prepolymer in the presence of the acrylate monomer, and/or the styrenic monomer of step iv); and vii) adding at least one ethylenically unsaturated nonionic monomer, and co-polymerizing it together with the acrylate monomer, and/or the styrenic monomer of step iv), to get the polyurethane/acrylic hybrid dispersion.

9 . A coating composition comprising the polyurethane/acrylic hybrid dispersion according to claim 8 .

10 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the polyurethane/acrylic hybrid dispersion is cold-blended with a polyacrylate dispersion under agitation to form a polyurethane/acrylic hybrid dispersion/polyacrylate dispersion blend.

11 . The polyurethane/acrylic hybrid dispersion according to claim 10 , wherein the polyurethane/acrylic hybrid dispersion and/or polyacrylate dispersion are modified by copolymerization with diacetone acrylamide or acetoacetoxyethyl methacrylate; and adipic acid dihydrazide, as crosslinker, is added into the polyurethane/acrylic hybrid dispersion/polyacrylate dispersion blend.

12 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the acrylate monomer is selected from the group consisting of acrylic acid, methyl (meth)acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl methacrylate, and combinations thereof.

13 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the at least one polyisocyanate is a diisocyanate.

14 . The polyurethane/acrylic hybrid dispersion according to claim 13 , wherein the diisocyanate is selected from bis(isocyanatomethyl)cyclohexane, hexamethylene diisocyanate, isophorone diisocyanate, and combinations thereof.

15 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the at least one polyol consists of polyether polyols, polyester polyols, polycarbonates, or mixtures thereof.

16 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the at least one polyol consists of a combination of polyether polyol and polyester polyol.

17 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein step vi) of the process further comprises adding a chain extender.

18 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the polyurethane/acrylic dispersion is free of organic solvent.

19 . The polyurethane/acrylic hybrid dispersion according to claim 8 , wherein the polyurethane/acrylic hybrid dispersion is free of particulate dimethylolpropionic acid (DMPA).

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Zhang Jiguang
• Guo Shouxue
• Wang Yujiang
• Feng Shaoguang
• Jiang Siyuan
• Wang Caifeng

Classifications

• C08F283/006 Primary

  on to polymers provided for in C08G18/00 (C08F283/004 takes precedence) · CPC title

• C09D133/14 Primary

  of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen · CPC title

• C08G18/672

  Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen · CPC title

• C08G18/4238

  derived from dicarboxylic acids and dialcohols · CPC title

• C08G18/10

  Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step · CPC title