Internally plasticized epoxide resins of triglycidyl isocyanurate, hydroxy functional urethane polymer and polycarboxylic acid anhydride

Claim 2

The process of claim 1 wherein the molecular weight of said polyurethanes having at least two terminal hydroxyl groups is between 1,000 and 3,000.

Claim 3

The process of claim 1 wherein said long-chain, organic polyurethanes having at least two free hydroxyl groups per molecule and free of other reactive groups are selected from the group consisting of an excess of linear polyoxyalkylene glycols reacted with an organic diisocyanate and an excess of linear polyesters having at least two terminal hydroxyl groups reacted with an organic diisocyanate.

Claim 4

A process for the preparation of a stable, subresinous, heat-hardenable epoxide resin, which when hardened, has increased flexibility without a substantial effect on its thermal properties, which consists essentially of the steps of reacting a mixture consisting essentially of (1) a crystalline triglycidyl isocyanurate having an epoxide oxygen content of at least 14 percent, (2) an organic polycarboxylic acid anhydride epoxide hardener in an amount sufficient that from 0.6 to 1.2 carboxylic acid anhydride groups are present for each epoxide group in said triglycidyl isocyanurate, and (3) from 10 to 30 percent by weight, based on the amount of (1) and (2) above, of long-chain organic polyurethanes having at least two free hydroxyl groups per molecule and free of other reactive groups, said polyurethanes having a molecular weight between 800 and 5,000, at a temperature and for a time sufficient to melt said components, immediately cooling said melt to below 80* C., and recovering said stable, sub-resinous, heat-hardenable epoxide resin.

Claim 5

The stable, sub-resinous, heat- hardenable epoxide resin produced by the process of claim 5.

Claim 6

Heat-hardenable liquid composition comprising the stable, sub-resinous, heat-hardenable epoxide resin produced by the process of claim 5 dissolved in an organic solvent.