Sizing composition and sized glass fibers and process

In a process of preparing sized glass fiber roving for use in preparing reinforced polymeric materials, the Improvement comprising:

• (a) treating the glass fibers during their formation with an aqueous sizing composition, comprising:
• (1) a major amount of the solids of the sizing composition in an epoxidized polar thermoplastic copolymer having 3 to about 12 parts of epoxy per 100 parts of the copolymer, where the comonomer is selected from vinyl acetate, acrylate, and polyurethane condensate monomer, where the copolymer has a Tg in the range of ambient temperatures to about 70.degree. C.,
• (2) one or more compatibilizing agents selected from unsaturated polyester polymers, polyvinylacetate homopolymer, or vinyl acetate-ethylene copolymers, in an amount of less than 20 weight percent of the film former,
• (3) one or more organo silane coupling agents,
• (4) one or more nonionic, cationic or anionic lubricants, and
• (5) an amount of water sufficient to make the percent solids of the sizing composition in the range of about 2 to about 30 weight percent,
• (b) gathering the treated glass fibers into one or more treated glass fiber strands,
• (c) drying the treated glass fiber strand or strands at a temperature above about 100.degree. C. for more than one hour to remove most of the moisture from the strand or strands,
• (d) gathering a plurality of dried glass fiber strands into a roving.

A process for preparing an aqueous sizing composition for treating glass fibers for use as reinforcement in polymeric materials, comprising:

• (a) combining an organo silane coupling agent having the free radical polymerizable organo moiety with water and acetic acid,
• (b) combining an epoxidized polyvinylacetate copolymer present in a major amount of the solids of the aqueous sizing composition with an unhydrolyzed or partially hydrolyzed aminofunctional organo silane coupling agent present in an amount in the range of about 0.1 to about 5 weight percent of the aqueous sizing composition,
• (c) adding vinyl acetate-ethylene copolymer to the organo silane mixture of step a),
• (d) adding the mixture of step c) to the water diluted mixture of step b),
• (e) adding water diluted amidated polyamine lubricant to the mixture of step d),
• (f) diluting the mixture of step e) with water to obtain the desired volume.