High performance aqueous coating compositions
View Patent ↗This invention relates to coating compositions that include water; a latex polymer and a silane coupling agent. The latex polymer preferably comprises acetoacetoxy functionality, or is a multistage latex, or is an acetoacetoxy functional multistage latex. The silane coupling agent is preferably a functionalized silane coupling agent (more preferably an epoxy-functional silane coupling agent). The compositions may be used to coat a variety of substrates, including wood, cement and fiber cement. Articles having the coating applied thereto are also provided.
1. A coating composition, comprising:
water;
a multistage latex polymer having acetoacetoxy functionality; and
at least about 0.25 weight % and less than about 10 weight %, based on the weight of the latex polymer, of a silane coupling agent that provides improved resistance to delamination from a cement substrate when a coating made from the composition is exposed for one hour at 60° C. to 1,034 kPa pressure from an automotive tire tread section heated to 60° C., wherein the silane coupling agent does not contain a functional group capable of reacting with another component of the coating composition.
2. The composition of claim 1 , wherein the multistage latex polymer comprises at least one soft stage having a Tg between about −65 and 30° C. and at least one hard stage having a Tg between about 30 and 230° C.
3. The composition of claim 2 , wherein the multistage latex polymer comprises 50 to 90 weight % soft stage polymer morphology having a Tg between about −5 and 25° C. and 10 to 50 weight % hard stage polymer morphology having a Tg between about 30 and 105° C., based on total polymer weight.
4. The composition of claim 2 , wherein the multistage latex polymer has a gradient Tg.
5. The composition of claim 1 , wherein the composition comprises at least 10 weight % multistage latex polymer, based on total solids of the composition.
6. The composition of claim 1 , wherein the multistage latex polymer is made using from 0.5 to 10 weight % acetoacetoxy functional monomer based on the total weight of the multistage latex polymer.
7. The composition of claim 1 , wherein the composition includes less than 10 weight % volatile organic compounds.
8. The composition of claim 1 , wherein the composition further comprises a low VOC coalescent in an amount of at least 1 weight %.
9. The composition of claim 1 , wherein the composition resists crush when two face-to-face coated embossed substrates are subjected to a pressure of 8 kg/cm 2 .
10. The composition of claim 1 , wherein the silane coupling agent is present in an amount of from 0.25 to 5 weight percent based on the weight of latex polymer.
11. The composition of claim 10 , wherein the silane coupling agent is present in an amount of from 0.5 to 2 weight percent based on the weight of latex polymer.
12. The composition of claim 1 , wherein the composition is in the form of a sealer layer atop a wood or porous substrate.
13. The composition of claim 1 , wherein the composition is in the form of a sealer layer atop a cementitious substrate.
14. The composition of claim 1 , wherein the composition is in the form of a topcoat layer atop a cementitious substrate.
15. The composition of claim 1 , wherein the coating composition resists damage from hot tires.