| abstract |
A sizing composition for reinforcement fibers that includes a cationic modified polyurethane dispersion, one or more silane coupling agents, and at least one lubricant is provided. The cationic modified polyurethane dispersion includes a dual end-capped polyurethane selected from a silane-terminated polyurethane, a ketoxime-terminated polyurethane, or a hybrid silane/ketoxime-terminated polyurethane where one end of the polyurethane is terminated with a silane group and the opposing end is terminated with a ketoxime group. The size composition is applied to reinforcement fibers and formed into chopped strand, wet-laid mats that can be used for a variety of purposes, including roofing products. Chopped strand mats formed from fibers sized with the inventive sizing composition maintains or improves the dry tear strengths and wet strengths compared to chopped strand mats made from fibers sized with a commercial sizing composition that does not contain a modified cationic polyurethane dispersion (e.g., SPUD). |