NONWOVEN FABRIC FOR ELECTRIC INSULATION, METHOD FOR PRODUCING THE SAME, PREPREG AND LAMINATE

摘要

PROBLEM TO BE SOLVED: To provide a printed-wiring board of which insulating substrate is consisted mainly of a nonwoven fabric and contains organic fiber pulp in the binder component bonding fiber chops to each other, wherein misdetection that a nondefective point is recognized as a defective point is prevented in inspection of a printed-wiring pattern with an optical automatic inspection system. SOLUTION: This nonwoven fabric for electric insulation is composed mainly of p-aramid fiber chops and contains organic fiber pulp as the binder for bonding the fiber chops to each other, wherein aggregate of the organic fiber pulp in the nonwoven fabric has <=1 mm maximum length. The nonwoven fabric is obtained by forming a first dispersion dispersing the p-aramid fiber as the main component and a second dispersion dispersing the organic fiber pulp used as the binder for bonding the fiber chops to each other, mixing the first dispersion with the second dispersion and making paper.