Aqueous sizing composition for producing sized glass fiber strands with improved slip flow properties

Aqueous sizing composition for treating glass fibers to yield sized glass fibers that are gathered into strands that have improved slip flow properties, comprising:

• (a) one or more non-starch film forming polymers that provide integrity to the glass fibers in an amount in the range of about 1 to about 20 weight percent of the aqueous sizing composition,
• (b) one or more coupling agents in an amount in the range of about 0.1 to about 4 weight percent of the aqueous sizing composition,
• (c) one or more nonionic lubricants in an amount in the range of about 0.5 to about 5 weight percent of the aqueous sizing composition,
• (d) a mixture of a substantially linear polyethylene-containing polymer with limited branching having a polydispersity index of less than 10 and a wax having a melting point greater than 50.degree. C. present in the aqueous sizing composition to give a weight ratio of polyethylene polymer to wax of about 10:1 to 1:10, where the amount of the mixture in the aqueous sizing composition is not greater than about 15 weight percent of the aqueous size, and
• (e) water in an amount to give a total solids for the aqueous sizing composition in the range of about 1 to about 30 weight percent.

Aqueous sizing composition for treating glass fibers that are gathered into strands that have improved slip flow properties, comprising:

• (a) one or more non-starch film forming polymers that provide integrity to the glass fibers in an amount in the range of about 1 to about 20 weight percent of the aqueous sizing composition,
• (b) one or more coupling agents in an amount in the range of about 0.1 to about 4 weight percent of the aqueous sizing composition,
• (c) a polyethylene polymer with limited branching having a polydispersity index of less than 10 and having a density greater than around 0.935 present in an amount of less than about 10 weight percent of the aqueous sizing composition,
• (d) one or more nonionic lubricants,
• (e) a wax having a melting point greater than 50.degree. C. present in the aqueous sizing composition in an amount ranging from 0 to about 2 weight percent of the aqueous sizing composition,
• (f) water in an amount to give a total solids for the aqueous sizing composition in the range of about 1 to about 30 weight percent.