Claims
- 1. A waterborne coating composition wherein the volatile organic content is less than 3.5 pounds per gallon and having a total solids content at application of greater than 30 percent, comprising pigment, crosslinking agent and a dispersion of polymeric microparticles in an aqueous medium wherein the microparticles are prepared by forming a mixture in aqueous medium of a vinyl monomer or mixture of vinyl monomers with greater than 30 percent by weight based on the microparticles of a polymer which is substantially hydrophobic such that when the polymer is mixed with the aqueous medium and vinyl monomer or mixture of vinyl monomers a majority of the polymer is in the organic phase and a separate aqueous phase is obtained; said polymer being essentially free of repeating acrylic or vinyl units in the backbone, has a molecular weight greater than 300 and contains functional groups which are capable of reacting with the crosslink agent; and particularizing said mixture into microparticles by high stress techniques followed by polymerizing the polymerizable species within the microparticles to produce the polymeric microparticles which are stably dispersed in the aqueous medium; and the aqueous medium of the microparticle dispersion being substantially free of water soluble polymer.
- 2. The coating composition of claim 1 wherein less than 20 percent of the polymer microparticles have a means diameter greater than one micron.
- 3. The coating composition of claim 2 wherein the polymeric microparticles have a mean diameter ranging from about 0.01 microns to about 10 microns.
- 4. The coating composition of claim 3 wherein the mean diameter of the polymer microparticles ranges from about 0.05 microns to about 0.5 microns.
- 5. The coating composition of claim 1 wherein the vinyl monomer or mixture of vinyl monomers is selected from acrylic monomers.
- 6. The coating composition of claim 1 wherein the polymer having molecular weight greater than 300 is selected from the group consisting of polyesters and polyurethanes.
- 7. The coating composition of claim 1 wherein the volatile organic content is less than 3.0 pounds per gallon.
- 8. The coating composition of claim 7 wherein the volatile organic content is less than 2.5 pounds per gallon.
- 9. The coating composition of claim 1 wherein the polymer microparticles are crosslinked.
- 10. The coating composition of claim 1 wherein the polymer microparticles are uncrosslinked.
- 11. A waterborne coating composition wherein the volatile organic consent is less than 3.5 pounds per gallon and having a total solids content at application of greater than 30 percent, comprising crosslinking agent and a dispersion of polymeric microparticles in an aqueous medium wherein the microparticles are prepared by forming a mixture in aqueous medium of a vinyl monomer or mixture of vinyl monomers with greater than 30 percent by weight based on the microparticles of a polymer which is substantially hydrophobic such that when the polymer is mixed with the aqueous medium and vinyl monomer or mixture of vinyl monomers a majority of the polymer is in the organic phase and a separate aqueous phase is obtained; said polymer being essentially free of repeating acrylic or vinyl units in the backbone, has a molecular width greater than 300 and contains functional groups which are capable of reacting with the crosslinking agent; and particulation said mixture into microparticles by high stress techniques followed by polymerizing the polymerizable species within the microparticles to produce the polymeric microparticles which are stably dispersed in the aqueous medium; the aqueous medium of the microparticle dispersion being substantially free of water soluble polymer.
Parent Case Info
This application is a continuation of application Ser. No. 07/357,828, fled May 30, 1989, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0269059 |
Jun 1988 |
EPX |
308115 |
Mar 1989 |
EPX |
1373531 |
Nov 1974 |
GBX |
1403794 |
Aug 1975 |
GBX |
1419199 |
Dec 1975 |
GBX |
2006229 |
May 1979 |
GBX |
Non-Patent Literature Citations (3)
Entry |
Backhouse, "Routes to Low Pollution Glamour Metallic Automotive Finishes", Journal of Coatings Technology, vol. 54, No. 693, Oct. 1982. |
Pearson, "Water-Based Basecoat for Automotive Industry", Polymer Paint Colour Journal, vol. 177, No. 4195, Jul. 1987. |
Oberflache+JOT, "Water-Based Enamel. Has the Breakthrough Succeeded?", Sep. 1985, pp. 48-49. |
Continuations (1)
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Number |
Date |
Country |
Parent |
357828 |
May 1989 |
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