METHOD FOR OPENING BUNDLE OF REINFORCING FIBER AND MANUFACTURING METHOD OF PREPREG

摘要

PROBLEM TO BE SOLVED: To provide a method for homogeneously opening a reinforcing fiber bundle almost free from generation of fluff, and a method for manufacturing prepreg having high surface smoothness and low weight. SOLUTION: This method opens a continuously running bundle (F) of reinforcing fiber while imparting a periodic change of tension by a tension changing means (5). The method is capable of inhibiting generation of the fluff by setting an absolute ratio|Vr/V|at 0.6-1.4, in the ratio Vr is a speed of the part of the tension changing means (5) contacting with the fiber bundle (F) and V is a running speed of the fiber bundle (F). The prepreg (P) is manufactured by opening the bundle of the reinforcing fiber (F) into a sheet and then impregnating a resin into the sheet.