Coating composition for extreme washable coatings comprising self-crosslinkable core-shell particles
A coating composition including: an aqueous dispersion of self-crosslinkable core-shell particles, where the core-shell particles include (1) a polymeric core at least partially encapsulated by (2) a polymeric shell having urethane linkages, keto and/or aldo functional groups, and hydrazide functional groups, where the polymeric core is covalently bonded to at least a portion of the polymeric shell, and an acrylic polymer, where the acrylic polymer is non-reactive with the polymeric core and the polymeric shell. A substrate coated with a coating formed from the coating composition and a method of improving stain resistance of a substrate are also disclosed.
1. A coating composition comprising:
an aqueous dispersion of self-crosslinkable core-shell particles, wherein the core-shell particles comprise (1) a polymeric core at least partially encapsulated by (2) a polymeric shell comprising urethane linkages, keto and/or aldo functional groups, and hydrazide functional groups, wherein the polymeric core is covalently bonded to at least a portion of the polymeric shell, and
an acrylic polymer, wherein the acrylic polymer is non-reactive with the polymeric core and the polymeric shell.
2. The coating composition of claim 1 , wherein the polymeric core comprises an addition polymer derived from ethylenically unsaturated monomers.
3. The coating composition of claim 2 , wherein the ethylenically unsaturated monomers comprise a (meth)acrylate monomer, a vinyl monomer, and/or a combination thereof.
4. The coating composition of claim 1 , wherein the polymeric shell comprises a water dispersible group.
5. The coating composition of claim 1 , wherein the core-shell particles are formed from a mixture of reactants comprising: (a) isocyanate-functional ethylenically unsaturated polyurethane prepolymers; (b) a Michael addition reaction product of ethylenically unsaturated monomers comprising a keto and/or aldo functional group, and a compound comprising at least two amino groups; (c) a hydrazide functional component; and (d) ethylenically unsaturated monomers.
6. The coating composition of claim 1 , wherein the polymeric core is completely free of keto and/or aldo functional groups.
7. The coating composition of claim 1 , wherein the acrylic polymer is added to the aqueous dispersion after formation of the core-shell particles.
8. The coating composition of claim 1 , comprising 10-50 wt % of the core-shell particles and 50-90 wt % of the acrylic polymer, based on total resin solids.
9. The coating composition of claim 1 , wherein the self-crosslinkable core-shell particles further comprise a fluorine-containing group and/or a silicon-containing group bonded to the polymeric shell.
10. The coating composition of claim 1 , wherein the polymeric core comprises a Tg of 0° C. to 50° C.
11. The coating composition of claim 1 , further comprising a rheology modifier.
12. The coating composition of claim 1 , further comprising a matting agent.
13. The coating composition of claim 1 , further comprising an inorganic pigment and/or filler.
14. The coating composition of claim 1 , wherein when the coating composition is applied to a substrate and dried to form a coating, the coating exhibits an improved stain resistance compared to the same coating composition not including the core-shell particles.
15. A substrate at least partially coated with a coating formed from the coating composition of claim 1 .
16. The substrate of claim 15 , wherein the substrate comprises an architectural component.
17. The substrate of claim 15 , wherein the substrate is non-metallic.
18. A method of improving stain resistance of a substrate comprising:
preparing a coating composition by:
preparing an aqueous dispersion of self-crosslinkable core-shell particles dispersed in an aqueous medium, wherein the core-shell particles comprise (1) a polymeric core at least partially encapsulated by (2) a polymeric shell comprising urethane linkages, keto and/or aldo functional groups, and hydrazide functional groups wherein the polymeric core is covalently bonded to at least a portion of the polymeric shell; and
adding an acrylic polymer to the aqueous dispersion, wherein the acrylic polymer is non-reactive with the polymeric core and the polymeric shell; and
applying the coating composition to a substrate.
19. The method of claim 18 , wherein the acrylic polymer is added to the aqueous dispersion after formation of the core-shell particles.
20. The method of claim 18 , wherein the coating composition comprises 10-50 wt % of the core-shell particles and 50-90 wt % of the acrylic polymer, based on total resin solids.