Water-soluble heat-press-bonding polyvinyl alcohol binder fiber of a sea-islands structure

摘要

By mixing a high-melting polyvinyl alcohol type polymer (A) and a low-melting water-soluble polymer (B) in a solvent for the polymer (A) to prepare a spinning solution and then subjecting the solution to low-temperature spinning so that the resulting filaments are solidified uniformly in the cross-sectional direction, there is formed a fiber of sea-islands structure comprising said high-melting polyvinyl alcohol type polymer (A) as the sea component and said low-melting water-soluble polymer (B) as the islands component. In this fiber, at least part of the islands component is present in a fiber zone ranging from the fiber surface to 2 mu m inside and the fiber surface contains substantially no islands component. This fiber ordinarily shows the performance of the matrix phase, i.e. the performance of a high-melting polyvinyl alcohol fiber; however, when the fiber is pressurized at high temperatures, the low-melting polymer (the islands component) is pushed out onto the fiber surface and there occurs heat bonding between fibers. Owing to this property of the fiber, a nonwoven fabric can be produced advantageously from the fiber.