Multiaxial stack rigidly connected by means of weld points applied by means of inserted thermoplastic webs

摘要

The present invention relates to a stack of fibrous materials including at least two unidirectional carbon fiber layers, each extending in different directions, wherein each one of the unidirectional layers is connected by means of at least one of the surfaces thereof to an adjacent web of thermoplastic fibers, at least one web being inserted between two consecutive unidirectional layers, characterized in that the link between each unidirectional layer and each adjacent web is provided by the web, by weld points which produce an intermittent overall weld, and in that said weld points also guarantee the cohesion of the stack, as well as the method for manufacturing same.

主权项

1. A cohesive stack of layers of dry unidirectional carbon fibers that are not held together by stitching or knitting wherein said cohesive stack includes diffusion channels for infusing a thermosetting resin into said cohesive stack to form a composite part, said cohesive stack comprising:
a first layer having a first surface and a second surface, said first layer comprising a plurality of unidirectional carbon fibers extending in a first direction, wherein said first layer is not impregnated with a polymeric binder nor is said first surface or second surface of said first layer coated with a polymeric binder; a second layer having a first surface and a second surface, said second layer comprising a plurality of unidirectional carbon fibers extending in a second direction, said second direction being different from said first direction, wherein said second layer is not impregnated with a polymeric binder nor is said first surface or second surface of said second layer coated with a polymeric binder; a first internal web comprising a plurality of thermoplastic fibers and having a first surface and a second surface, said first surface of said first internal web being located adjacent to the second surface of said first layer and said second surface of said first internal web being located adjacent to the first surface of said second layer; a first external web comprising a plurality of thermoplastic fibers and having a first surface and a second surface, said second surface of said first external web being located adjacent to the first surface of said first layer; a first set of linear weld points that provide welding together of said first internal web, first external web, first layer and second layer, said first set of linear weld points comprising a plurality of first weld lines that are aligned collinearly in a first weld line direction and which each have a width, a head and a tail wherein the length of each of said first weld lines between said head and said tail is from 10 millimeters to 100 millimeters and wherein the head of each first weld line is spaced a distance from the tail of the adjacent first weld line to form openings between said first weld lines, said openings each having a length; a second set of weld points located in the openings between said first weld lines, said second set of weld points providing welding together of said first internal web, first external web, first layer and second layer, said second set of weld points comprising a plurality of second weld lines that each have a width, a head and a tail wherein the length of each of said second weld lines between said head and said tail is from 10 millimeters to 100 millimeters, said second weld lines not being aligned collinearly wherein each second weld line extends in a direction that is different from said first weld line direction and wherein the length of said openings between said first weld lines and the length of said second weld lines are such that the head of each second weld line overlaps the tail of the first weld line adjacent thereto and the tail of each second weld line overlaps the head of the first weld line adjacent thereto; a plurality of first weld point perforations which are located within said first weld points and which form diffusion channels for said thermosetting resin wherein each first weld point perforation extends transversally through said first and second layers and said first external web and said first internal web; and a plurality of second weld point perforations which are located within said second weld points and which form diffusion channels for said thermosetting resin wherein each second weld point perforation extends transversally through said first and second layers and said first external web and said first internal web and wherein there is a sufficient number of first and second weld points to provide said cohesive stack of layers of dry unidirectional carbon fibers that are not held together by stitching or knitting.