Rheology modifier

摘要

The present invention relates to a composition comprising a hydrophobically modified alkylene oxide polyurethane characterized by having a Mw of from 50,000 to about 150,000 Daltons and a polydispersity of 2.5 to about 5.0. The present invention further relates to a multi-step process for the preparation of the hydrophobically modified polymer.

主权项

1. A process comprising the steps of:
a) contacting a polyisocyanate branching agent with a stoichiometric excess of a water-soluble polyalkylene glycol under such conditions to form a mixture of the polyalkylene glycol and a branched poly-hydroxyalkylene oxide urethane; b) contacting the mixture of the polyalkylene glycol and the branched poly-hydroxyalkylene oxide urethane with a stoichiometric excess of a difunctional linking agent selected from the group consisting of diisocyanates, epihalohydrins, and gem-dihalides, under such conditions to form a branched urethane polymer containing hydroxyl-reactive end groups; and c) contacting the branched urethane polymer containing hydroxyl-reactive end groups with a capping agent under such conditions to form a hydrophobically modified alkylene oxide urethane, wherein the capping agent is characterized by either of the following formulas:
R2(OY)x—ZH orwhere R2 is a C4-C30-alkyl, -aryl, or -aralkyl group; R3 is H or a C4-C30-alkyl, -aryl, or -aralkyl group; R4 is a C4-C30-alkyl, -aryl, or -aralkyl group; Y is a C2-C8-alkylene group; W is N or P; x is an integer from 0 to 200; and Z is O or NH.