Method of forming glass fiber

Claim 1

In the method of forming glass fiber strands useful for the reinforcement of resinous articles which comprises drawing glass streams through orifices in a bushing to form individual glass fibers, moving the fibers away from the bushing at a high rate of speed, applying an aqueous sizing solution thereto while they are moving at this speed and gathering the fibers into the form of the strand the improvement comprising: applying as the aqueous sizing solution an aqueous sizing composition comprising a phenolic epoxy resin; the reaction product of a partial ester of a polycarboxylic acid containing one or more unesterified carboxyl groups with a compound containing more than one epoxy group; a dual component emulsifier system having therein a polyethylene glycol emulsifier and a second emulsifier consisting essentially of the reaction product of propylene glycols and ethylene oxide; a silane coupling agent and a saturated fatty triglyceride.