A process reaction between: (1) a compound that contains one or more epoxide moieties per molecule, and (2) a compound that contains one or more primary aliphatic hydroxyl groups per molecule; is catalyzed by: (3) a catalyst compound containing one or more trifluoromethanesulfonate moieties and one or more silyl moieties and run at a temperature of no more than 130.degree. C., such that the catalyst preferably catalyzes reaction at the primary aliphatic hydroxyl group, so that the resulting resin does not gel.