초록 ▼

Difunctional, hydroxyl-terminated polymers in which the terminal hydroxyl group is non-primary or hindered are end-capped to provide unhindered, primary, terminal hydroxyl groups which promote an improved cure and improved mechanical properties of the cured elastomer. End-capping chemicals have an h

Difunctional, hydroxyl-terminated polymers in which the terminal hydroxyl group is non-primary or hindered are end-capped to provide unhindered, primary, terminal hydroxyl groups which promote an improved cure and improved mechanical properties of the cured elastomer. End-capping chemicals have an hydroxyl-reactive group at one end and a group at the other end which is removable to provide a primary, unhindered hydroxyl group. Short-chain, hydroxyl-terminated polymers are chain-extended with a diisocyanate.

대표청구항 ▼

[ What is claimed is:] [1.] A method for improving the curability of a hydroxyl-terminated polymer comprising,providing an end-capping compound having the formula X--Q--(CH.sub.2).sub.n --O--Z; wherein X is a group which reacts readily with the terminal hydroxyl groups of the polymer to attach said

[ What is claimed is:] [1.] A method for improving the curability of a hydroxyl-terminated polymer comprising,providing an end-capping compound having the formula X--Q--(CH.sub.2).sub.n --O--Z; wherein X is a group which reacts readily with the terminal hydroxyl groups of the polymer to attach said compound to said polymer; Z is a blocking group which does not react with free hydroxyl groups and which may be removed from the linked oxygen under conditions which do not detach the residue of said compound from the termini of said polymer; Q is nothing or is any chemical moiety which does not interfere with attachment of said compound to said polymer, removal of said Z moiety or subsequent curing of the end-capped polymer, and n is 1 or 2;reacting said end-capping compound with said polymer; andremoving Z from said end-capped polymer to provide primary, unhindered hydroxyl groups at the termini of said end-capped polymer. [12.] A method of preparing a cured elastomer comprising, end-capping/deblocking an hydroxyl-terminated polymer in accordance with the method of claim 1, and curing said polymer with an isocyanate having a functionality of 2 or greater. A method according to claim 12 wherein an NCO/OH ratio of at least about 0.5. A method according to claim 1 wherein prior to end-capping said hydroxyl-terminal polymer, said polymer is reacted with a diisocyanate to extend the chain length.