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US 4,061,618 AGranted
Process for preparing stable polyurethane latices
AssigneeNational Starch and Chemical Corporation
InventorsHenry Stanley, Dilip K. Ray-Chaudhuri
Life of this patent
Estimating the term…
Abstract
Stable polyurethane polymer latices are obtained by incorporating specified amounts of polyethylene glycol into the backbone of various polyurethane polymers. The polyurethane latices are non-ionic but can assume an anionic or cationic character by the addition of anionic or cationic emulsifying or surface active agents. The latices have wide utility, for example, as adhesives, coatings, textile sizes, binders, and in molding applications.
Claims9
A process for preparing a predominantly linear polyurethane latex comprising the steps:
- a. reacting by initially heating an organic polyisocyanate and an organic compound containing at least two reactive hydrogen atoms as determined by the Zerewitinoff method and having a molecular weight of from about 300 to about 20,000, a portion of which is a polyethylene glycol of molecular weight from 600 to 20,000 in proportions such that the ratio of isocyanate groups to reactive hydrogen atoms is in the range of from 0.7 to 1.3, and said polyethylene glycol is present in an amount of from 2 to 12% by weight of polymer solids,
- b. terminating the polymerization reaction by addition of a terminating agent thereto when a desired viscosity is reached and thereafter,
- c. adding water to the reaction mixture in an amount so as to produce a latex containing from about 20 to 60% solids, by weight.
Dependencies are inferred from the claim text.