POROUS THREE-LAYER LAMINATE SHEET AND METHOD FOR MANUFACTURING SAME, AND SEPARATOR FOR ELECTRICITY STORAGE ELEMENT COMPRISING THREE-LAYER LAMINATE SHEET

摘要

This three-layer laminate sheet provided with porous fiber layers consisting of a core material of a nonwoven fabric composed mainly of thermoplastic fibers, and a layer above and a layer below the core material composed mainly of fine diameter cellulose fibers, wherein the air resistance of the three-layer laminate sheet, as measured by the Gurley method, is 1000 seconds/100 mL or less, the mass per unit area of the three-layer laminate sheet is in the range of 2 g/m² to 15 g/m², and the thickness of the three-layer laminate sheet is in the range of 5 μm to 40 μm. If the upper porous fiber layer is specified as (P), the lower porous fiber layer is specified as (Q), the nonwoven fabric is specified as (S), and the three-layer laminate sheet composed of P, Q and S is specified as (P/S/Q), a method for manufacturing the three-layer laminate sheet involves overlapping (P) and (Q) with (S), which has been prepared in advance, so as to attain (P/S/Q), and then integrating (P/S/Q) by applying pressure while in an overlapping state.