Method for producing a water-permeable covering on granular water-soluble substances
AssigneeAshland Oil, Inc.
InventorsHubert Kogler, Reinhard Winter, Peter Kuhlmann
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Abstract
The invention relates to a method for producing a water-permeable covering on granular, water-soluble substances by coating them with a synthetic resin. The method of the invention uses a coating composition which comprises a polyisocyanate and a polyol component of a condensation product from phenols and aldehydes, a softener containing hydroxyl groups and optionally a diluent containing hydroxyl groups. The coating composition is cured at room temperature with an amine as a catalyst.
Claims30
A method for producing a water-permeable covering on granular, water-soluble substances by coating said substances with a synthetic resin which comprises:
- (a) covering said granular, water-soluble substances with a coating composition which comprises a polyisocyanate and a polyol component that includes:
- (1) condensation product of phenols and aldehydes, and
- (2) hydroxyl group containing softener;
- wherein said condensation product is 10-90% by weight of said polyol component and wherein the relative amounts of said polyisocyanate and said polyol component are such as to provide a polyurethane covering upon hardening;
- and
- (b) hardening said coating composition employing an amine as a catalyst to provide a cured polyurethane covering.
Dependencies are inferred from the claim text.