Thermosetting coating compositions for the sealing of fiber reinforced plastics

摘要

High solids thermosetting organic solvent solution coating compositions are disclosed which are particularly useful for sealing the pores in fiber reinforced plastics. These compositions contain a mixture of resins comprising (1) from 30% to 70% of one or more hydroxy functional resins having a number average molecular weight of at least about 700, a Gardner bubble viscosity less than about Z4 measured in methyl ethyl ketone at 90% solids at 25 DEG C., and at least 5% of the hydroxy groups thereof being primary hydroxy groups, (2) from 10% to 70% of low molecular weight epoxy ester made by esterifying one or more resinous polyepoxides having a 1,2-epoxy equivalency of at least 1.2 with an approximately stoichiometric proportion of monocarboxylic fatty acid to provide an essentially epoxy-free ester having a Gardner bubble viscosity less than Z4 at 75% solids in xylol at 25 DEG C., and (3) the balance of the mixture, but not less than 15% thereof, being a curing agent having a plurality of groups reactive with the hydroxy groups in the hydroxy resin and in the epoxy ester.