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Article: Reader responds to Q & A on manufacturing synthetic resins.(Letter to the Editor)
- Article from:
- JCT CoatingsTech
- Article date:
- August 1, 2004
- Author:
CopyrightCOPYRIGHT 2004 Federation of Societies for Coatings Technology. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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TO THE EDITOR:
While the answer to the recent question about manufacturing PUD's, which appears in the June 2004 issue of JCT COATINGSTECH (page 22), provides some general worthwhile advice, there are some specific recommendations that should be followed when manufacturing PUD's.
I assume that the "prepolymer process" is being used, since this is the predominant manufacturing method. In the first step of the process a polyol, an excess of isocyanate, and a dihydroxy acid are heated to form a prepolymer. M-Pyrol is added to control the viscosity of the prepolymer. After the addition of a tertiary amine, to neutralize the acid group, in the second step, ...