Thermoplastic prepreg, fiber-reinforced plastic, and manufacturing method therefor

A thermoplastic prepreg obtained by impregnating a discontinuous reinforcing fiber web with a thermoplastic resin, the thermoplastic prepreg satisfying at least one of the following features (A) or (B):

• feature (A):
• a plurality of incisions cut at least a portion of discontinuous reinforcing fibers constituting the discontinuous reinforcing fiber web,
• wherein the incisions are regularly arranged and reach a depth of 100% in the thickness direction of the discontinuous reinforcing fiber web;
• and
• feature (B):
• a fiber length variation region of the discontinuous reinforcing fibers constituting the discontinuous reinforcing fiber web is included, where the discontinuous reinforcing fibers have a coefficient of variation in fiber length of is 40% or more,
• wherein when a histogram of fiber length distribution of the discontinuous reinforcing fibers in the fiber length variation region is created under the following conditions, the highest frequency is 70% or less:
• lengths of discontinuous reinforcing fibers randomly selected from the discontinuous reinforcing fibers in the fiber length variation region are measured, and a range from minimum fiber length to maximum fiber length is equally divided into nine fiber length ranges, thereby creating a histogram with a grade number of 9 on a horizontal axis;
• and
• frequency on a vertical axis, where the frequency is a ratio [%] of number of single fibers of discontinuous reinforcing fibers belonging to each grade when the total number of randomly selected single fibers of the discontinuous reinforcing fibers is taken as 100%.