Resinous composition and method

Claim 1

A METHOD OF PREPARING AN OBJECT COMPOSED ESSENTIALLY OF GLASS FIBER FABRIC IMPREGNATED WITH RESIN, SAID OBJECT HAVING AN IMPROVED RESISTANCE TO HEAT AND UNIFORM ELECTRICAL CHARACTERISTICS TO UHF WAVES WHICH COMPRISES: LOWERING THE PH OF AN AQUEOUS SOL OF COLLOIDAL SILICA TO BELOW 7 BY THE ADDITION OF WEAK ACID, MIXING SAID SOL IN APPROXIMATELY EQUAL PROPORTIONS WITH A WATERMISCIBLE, ORGANIC SOLVENT, ADDING TO THIS MIXTURE A DISPERSION OF HEAT RESISTANT ORGANIC THERMOSETTING RESIN IN SOLVENT, SUBJECTING THE RESULTING SILICEOUS, RESINOUS MIXTURE TO HEAT AND SUBATMOSPHERIC PRESSURE TO THEREBY CONCENTRATE THE MIXTURE BY EVAPORATION OF WATER AND SOLVENT, SAID CONCENTRATED MIXTURE CONTAINING FROM 20% TO 75% ON A SOLVENT-FREE BASIS OF COLLOIDAL SILICA, IMPREGNATING A WOVEN GLASS FIBER FABRIC WITH SAID RESIN-SILICA MIXTURE WHILE SAID FABRIC IS IN NORMAL FORM, THEN SUBJECTING THE FABRIC TO TENSION APPLIED ON THE BIAS OF SAID FABRIC TO REDUCE VOID SPACES BETWEEN THE FIBERS, AND CURING THE IMPREGNATED FABRIC WHILE THE FIBERS ARE IN SUCH TENSIONED AND REARRANGED CONDITION.