Urethane acrylic hybrid polymer dispersion with robust dry/wet adhesion and basecoats prepared therefrom
This invention relates to urethane acrylic hybrid polymer dispersion with robust dry/wet adhesion and the basecoats prepared therefrom for automotive applications. In this system, the polyurethane dispersion (PUD) prepolymer is based on a combination of polyols and aliphatic diisocyanates. The acrylic portion is based on (meth)acrylated monomers. A combination of this hybrid polymer dispersion and other resins having defined glass transition temperature (T g ) values, organic and/or inorganic rheology modifiers, and different additives including pigment, dispersant, and defoamer are used to prepare waterborne basecoats having modified appearance and performance. The final coatings show excellent dry/wet adhesion to the primer for automotive applications.
1 . A urethane acrylic hybrid polymer dispersion, comprising:
a. a polyurethane dispersion prepolymer comprising (a) at least one polyester diol; and (b) at least one diisocyanate selected from an aliphatic diisocyanate or cycloaliphatic diisocyanate; (c) at least one hydroxy functional carboxylic acid; and (d) optionally one low-molecular-weight polyol having a molecular weight between 60 and 200; and
b. an acrylic part comprising at least one monomer having polymerizable functionality selected from the group consisting of a (meth) acrylate, allyl, and (meth)acrylamide, wherein said monomer contains at least one pendant functional group selected from the group consisting of ureido, morpholino, phosphate, and any combination thereof, wherein the acrylic part is present in the range of 10 wt. % to 90 wt. % based on total weight of the hybrid polymer dispersion;
wherein the urethane acrylic hybrid polymer dispersion is formed by combining the polyurethane dispersion prepolymer and the acrylic part.
2 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the acrylic part has a T g in the range of −20° C. to 60° C.
3 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the acrylic part has a T g in the range from −10° C. to 40° C.
4 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the acrylic part is present in the range from 25 wt. % to 75 wt. %, based on the total weight of the hybrid polymer dispersion.
5 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the (meth)acrylated monomer is selected from the group consisting of ureido methacrylate, phosphate ester of polypropylene glycol methacrylate, and 2-N-morpholinoethyl acrylate.
6 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the (meth)acrylamide monomer is selected from the group consisting of dimethylaminopropyl methacrylamide and ureidoethyl methacrylamide.
7 . The urethane acrylic hybrid polymer dispersion of claim 1 ,
wherein the allyl monomer is an allyl ether.
8 . The urethane acrylic hybrid polymer dispersion of claim 1 ,
wherein the allyl monomer is selected from the group consisting of allyl ether comprising 2-imidazolidinone, 1-(2-aminoethyl)-, N,N-bis(2-hydroxy-3-(2-propen-1-yloxy) propyl), and N-(2-hydroxy-3-(2-propen-1-yloxy) propyl) derivatives.
9 . The urethane acrylic hybrid polymer dispersion of claim 1 , comprising 0.2 wt. % to 15 wt. % of the at least one monomer having polymerizable functionality, based on the total monomer weight of the acrylic part.
10 . The urethane acrylic hybrid polymer dispersion of claim 1 , comprising 2.5 wt. % to 7.5 wt. % of the at least one monomer having polymerizable functionality, based on the total monomer weight of the acrylic part.
11 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the aliphatic diisocyanate is selected from the group consisting of 1,6-hexamethylene diisocyanate, tetra-methyl xylylene diisocyanate (TMXDI), isophorone diisocyanate, or 4,4′-dicyclohexylmethane diisocyanate.
12 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the polyester polyol is selected from the group consisting of poly(glycol adipates), poly(ethylene terephthalate) polyols, polycaprolactone polyols, alkyd polyols, and mixtures thereof.
13 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the polycarbonate diol is selected from the group polycarbonate diols consisting of 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl 1,5-pentane diol, 1,6-hexanediol, or mixtures thereof.
14 . The urethane acrylic hybrid polymer dispersion of claim 1 , wherein the low-molecular-weight polyol has up to 10 carbon atoms per molecule.