Claims
- 1. A polymeric, macromonomeric, or oligomeric high-temperature-gelation-resistant material that includes both sterically hindered carboxylic acid groups and carboxylic acid-reactive groups, such that the material has an improved pot-life and exhibits a viscosity below about 1000 cps for at least about 60 minutes at a temperature in the range of about 115° C. to 180° C.
- 2. The high-temperature-gelation-resistant material of claim 1, wherein the acid-reactive groups are hydroxyl groups and the carboxylic acid groups are provided by methacrylic acid monomers, and wherein the material is formed by free-radical polymerization of methacrylic acid monomers with at least one hydroxy-functional comonomer and, optionally, at least one other acrylate or methacrylate comonomer.
- 3. The high-temperature-gelation-resistant material of claim 1, wherein the material exhibits a viscosity below about 500 cps for at least about 120 minutes at about 150° C.
- 4. The high-temperature-gelation-resistant material of claim 1, wherein the material exhibits a viscosity below about 300 cps for at least about 180 minutes at about 150° C.
- 5. The high-temperature-gelation-resistant material of claim 1, wherein the material exhibits an Mn between about 1,000 and 50,000 for at least about 60 minutes at a temperature in the range of about 115° C. to 180° C.
- 6. A process for improving the pot life of a high-temperature-gelation-resistant material that comprises copolymerizing sterically hindered carboxylic acid-containing monomers with at least one hydroxy-functional comonomer and, optionally, at least one other acrylate or methacrylate comonomer, at a sufficient polymerization temperature and for a sufficient time to create a copolymer with a viscosity below about 1000 cps or an Mn of about 1,000 to 50,000, wherein the viscosity of the material remains below about 1000 cps or the Mn remains between about 1,000 and 50,000 for at least about 60 minutes at a temperature in the range of about 115° C. to 180° C.
- 7. A process for preparing an isocyanate-based, curable oil-in-water emulsion, comprising the steps of:
(i) admixing (a) an unblocked isocyanate crosslinking agent containing at least two reactive isocyanate groups, the agent being substantially hydrophobic and non-dispersible in water, with (b) a mixture of the high-temperature-gelation-resistant material of claim 1, and an aqueous medium, wherein, in the mixture, the high-temperature-gelation-resistant material is water-dispersible; in proportions and under conditions sufficient to produce a substantially homogenous curable water-in-oil emulsion having a VOC content of about 2.1 lbs/gal (252 g/l) or less; then (ii) admixing the curable water-in-oil emulsion from step (i) with an aqueous medium in proportions and under conditions sufficient to produce a substantially homogenous oil-in-water emulsion of the high-temperature-gelation-resistant material and the isocyanate crosslinking agent in water, the oil-in-water emulsion having a VOC content of about 2.1 lbs/gal (252 g/l) or less.
- 8. The process of claim 7, wherein the admixing of step (i) comprises:
adding the aqueous medium to the high-temperature-gelation-resistant material to produce a substantially homogenous mixture; adding the isocyanate crosslinking agent to the substantially homogenous mixture to produce the water-in-oil emulsion; adding an aqueous medium to the water-in-oil emulsion until a phase inversion occurs, thereby forming the oil-in-water emulsion; and adding additional aqueous medium to the oil-in-water emulsion such that the oil-in-water emulsion has a desired solids content and viscosity.
- 9. The process of claim 7, wherein the high-temperature-gelation-resistant material is a copolymer comprising styrene and a hydroxyalkyl acrylate or methacrylate.
- 10. The process of claim 9, wherein the hydroxyalkyl acrylate or methacrylate comprises 4-hydroxybutyl methacrylate or 4-hydroxybutyl acrylate.
- 11. The process of claim 9, which further comprises at least one additional comonomer.
- 12. The process of claim 11, wherein the at least one additional comonomer is selected from the group consisting of methyl methacrylate, butyl acrylate, methacrylic acid, and a mixture thereof.
- 13. The process of claim 7, wherein the high-temperature-gelation-resistant material is from about 30% to about 60% neutralized.
- 14. The process of claim 8, which further comprises adding a neutralizing agent to the aqueous medium.
- 15. The process of claim 7, wherein the aqueous medium comprises water added in an amount such that the water-in-oil emulsion comprises up to about 40% by weight water.
- 16. The process of claim 7, wherein the unblocked isocyanate crosslinking agent is selected to comprise a tertiary polyisocyanate.
- 17. A curable water-in-oil emulsion comprising a substantially homogeneous emulsion of water in a mixture of the high-temperature-gelation-resistant material of claim 1, which has been at least partially neutralized, has a hydroxyl content of at least 1.5 wt % (based on 48 wt % solids), has a Tg of less than about 0° C., and is dispersible in water, with an unblocked isocyanate crosslinking agent, which contains at least two reactive isocyanate groups and which is substantially hydrophobic and non-dispersible in water, the curable water-in-oil emulsion having a VOC content of about 2.1 lbs/gal (252 g/l) or less.
- 18. A coated substrate comprising the high-temperature-gelation-resistant material of claim 1 or a reaction product thereof.
- 19. The coated substrate of claim 18, wherein the high-temperature-gelation-resistant material or a reaction product thereof is present in a coating formed on the article.
- 20. A coated substrate comprising a high-temperature-gelation-resistant material, having an improved pot life and formed according to the process of claim 6, or a reaction product thereof.
- 21. The coated substrate of claim 20, wherein the high-temperature-gelation-resistant material or a reaction product thereof is present in a coating formed on the article.
- 22. An article comprising an isocyanate-based, curable oil-in-water emulsion formed according to the process of claim 7.
- 23. The article of claim 22, wherein the high-temperature-gelation-resistant material or a reaction product thereof is present in a coating formed on the article.
- 24. An article comprising an isocyanate-based, curable water-in-oil emulsion formed according to the process of claim 17.
- 25. The article of claim 24, wherein the high-temperature-gelation-resistant material or a reaction product thereof is present in a coating formed on the article.
- 26. A process for providing a coating on an article comprising:
applying an isocyanate-based, curable oil-in-water emulsion formed according to the process of claim 7 on an article; and drying the emulsion to form a coating.
- 27. A process for providing a coating on an article comprising:
applying an isocyanate-based, curable oil-in-water emulsion formed according to the process of claim 17 on an article; and drying the emulsion to form a coating.
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation-in-part of co-pending U.S. patent application Ser. Nos. 09/032,518 and 09/032,519, both filed on Feb. 27, 1998, and co-pending U.S. patent application Ser. No. 09/609,837, filed on Jul. 5, 2000, the entire disclosures of each of which are incorporated herein by express reference thereto.
Continuation in Parts (3)
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Number |
Date |
Country |
Parent |
09032518 |
Feb 1998 |
US |
Child |
09736126 |
Dec 2000 |
US |
Parent |
09032519 |
Feb 1998 |
US |
Child |
09736126 |
Dec 2000 |
US |
Parent |
09609837 |
Jul 2000 |
US |
Child |
09736126 |
Dec 2000 |
US |