LIGHTWEIGHT ULTRA-STRONG SHEET AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain a lightweight inexpensive ultra-strong sheet by constituting the sheet of a two-layered laminated structure of a stretched material selected from a biaxial or multi- axial yarn laminated nonwoven fabric obtained from a tape with tensile strength of a specific value or more composed of ultra-high mol.wt. polyethylene with intrinsic viscosity of a specific value or more and a longitudinal and lateral laminated nonwoven fabric of wide reticulated webs and a sheet material. CONSTITUTION:Ultra-high mol.wt. polyethylene with intrinsic viscosity of 5dl/g or more (measured in a decalin soln. at 135 deg.C) is stretched to form a stretched material with tensile strength of 1.0 GPa or more and this stretched material is formed into a tape form and a number of the obtained stretched tapes are laminated so that the orientation axes of them cross each other at a right angle and thermally fused at intersecting points to obtain a biaxial or multiaxial yarn laminated nonwoven fabric 2. The stretched material is split under tension by a splitter to be formed into a reticulated web shape and a number of the obtained wide split webs are laminated longitudinally and laterally through an adhesive to form a nonwoven fabric 2. Non-combustion or fire-retardant sheet materials 3, 4 are laminated to both surfaces of the yarn laminated nonwoven fabric 2 or the longitudinally and laterally laminated nonwoven fabrics of the wide reticulated webs through an adhesive to obtain an ultra-strong sheet 1.