Claims
- 1. A process for the preparation of thermal oxidation color stabilized cured anionic polyurethanes, comprising preparing a water dispersed polyurethane having pendant acid groups, said polyurethane being prepared from the reaction of a polyhydroxy polyol and a polyhydroxy polyol having a pendant carboxylic acid group, with a polyisocyanate, said acid groups having been neutralized with a volatile alkyl or alkanol tertiary amine which vaporizes at a temperature below about 150.degree. C., said water dispersed anionic polyurethane being further treated with a hydrazide being an additive selected from the group consisting of monohydrazide and a polyhydrazide in an amount sufficient to impart thermal oxidation color stability to the polyurethane during curing, there being an absence of reactive NCO terminal groups when a polyhydrazide is selected and curing the polyurethane at a temperature of from about 150.degree. C. to about 190.degree. C. to provide a product which has thermal oxidation color stability.
- 2. The process of claim 1, wherein the hydrazide is one selected from the group consisting of a carbohydrazide, adipicdihydrazide and oxalyldihydrazide.
- 3. The process of claim 2, wherein the hydrazide is a carbohydrazide.
- 4. The process of claim 1, wherein curing is for a period of at least 10 minutes to about 60 minutes.
Parent Case Info
This is a continuation-in-part of copending application Ser. No. 138,761, filed on Apr. 9, 1980, abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3188302 |
Lorenz et al. |
Jun 1965 |
|
3923713 |
Hermann |
Dec 1975 |
|
3929726 |
Schollenberger et al. |
Dec 1975 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
138761 |
Apr 1980 |
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