PROCESS FOR MAKING CURABLE, MULTI-LAYER FIBER-REINFORCED PREPREG

摘要

Multilayer prepregs are formed by stacking layers of unidirectional prepregs in which continuous reinforcing fibers are aligned in a single direction. The unidirectional prepregs are made by impregnating aligned tows of a reinforcing fiber with a solid thermosetting resin that softens at a temperature below its cure temperature. The layers of the stack are bonded together by softening and then re-cooling the resin portion of the individual prepreg layers. The multilayer prepreg is then molded and cured to form a composite part.

主权项

1. A method for making a curable multiaxial prepreg, comprising
A) impregnating multiple aligned fiber tows with a heat-softened, thermosetting resin composition without curing the thermosetting resin composition, wherein the thermosetting resin composition is solid and non-tacky at 25° C., has a curing temperature of at least 80° C. and a Mettloff softening temperature below its curing temperature, and then cooling the composition to below its Mettloff softening temperature to form a unidirectional prepreg which is non-tacky at 25° C. and in which the resin infusion is at least 70%, the prepreg containing up to 500 g/m2 of unidirectional reinforcing fibers; B) stacking two or more layers of the unidirectional prepreg to form a multilayer stack in which the orientation of the unidirectional fibers in at least one prepreg layer is different from the orientation of the unidirectional fibers in at least one other prepreg layer to form a multilayer stack containing at least 500 g/m2 of reinforcing fibers; C) heat-softening at least a portion of the thermosetting resin composition of at least some of the stacked prepreg layers without curing the thermosetting resin composition, and then cooling and thereby re-hardening the thermosetting resin composition while maintaining the adjacent layers of the stack in contact with each other to form adhesive bonds between the layers of the stack and produce the curable multiaxial prepreg.