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AssigneeThe United States of America as represented by the Secretary of the Army
InventorChester W. Huskins
Estimating the term…
By use of the reaction for the preparation of biurets from isocyanates (i, condensation products of isocyanates and water) a variety of tri-functional isocyanates are made available as the curing agents for rubbery-solid-filled compositions employing hydroxy-terminated polybutadiene (HTPB) binder to obtain beneficial binder chain extension and crosslinking functions. The tri-functional isocyanates are prepared by the reaction of three moles of a diisocyanate selected from the diisocyanates consisting of dimeryl diisocyanate, isophorone diisocyanate, and trimethylhexamethylene diisocyanate with one mole of water in an appropriate solvent (e.g., p-dioxane). The reaction occurs at solvent reflux temperature. The reaction must be carried out under a blanket of dry nitrogen. The product, a triisocyanate, is obtained ready for use at the end of the reaction when the solvent is stripped from the reaction product. The product achieves improved mechanical properties for a composition containing high solids loadings of either inert ingredients or oxidizer and combustible ingredients depending on intended use for the composition.
A tri-functional isocyanate prepared by the method comprising reacting together in a reflux vessel containing an excess amount of the reacting solvent p-dioxane, three moles of a diisocyanate, and one mole of water selected from distilled water and deionized water, said diisocyanate selected from the group of diisocyanates consisting of isophorone diisocyanate, trimethyl-hexamethylene diisocyanate, and dimeryl diisocyanate, said reacting being carried out under a blanket of dry nitrogen and at reflux conditions for a period of time from about one to about two hours to complete said reacting to form said tri-functional isocyanate in said reacting solvent that is stripped from the reflux vessel to yield said tri-functional isocyanate which is ready for immediate use as a crosslinking agent in a hydroxy-terminated polybutadiene binder system.
Dependencies are inferred from the claim text.