Prepreg with integrated multi-dimensional gas venting network
View Patent ↗Composite prepreg including a gas venting network that allows multi-dimensional escape of gas from the prepreg during the curing process. Penetrable barriers are also provided between the matrix precursor elements to promote long-term storability of the prepreg at ambient temperatures. All or a portion of the gas venting network may be integrated with the penetrable barriers.
1. A method for making a composite part comprising the steps of:
providing a fibrous element comprising a first side and a second side;
applying a sheet of resin as a single entity to the first side of said fibrous element, said sheet of resin comprising a flat side and a notched side, said flat side being located on the first side of said fibrous element and said notched side having alternating upper resin surfaces and lower resin surfaces; said sheet of resin comprising a plurality of resin elements consisting of parallel lines of one or more thermosetting resins that are separated from each other by a resin barrier zone comprising a penetrable barrier material wherein said resin elements extend between the flat side of said sheet of resin and the upper resin surfaces, said sheet of resin further comprising resin bridges which extend across said resin barrier zones at the flat side of said sheet of resin to form partially closed resin hairier zones that are partially filled with said penetrable barrier material, said resin bridges providing connections between said resin elements along the flat side of said sheet of resin, said resin bridges consisting of one or more thermosetting resins and each of said resin bridges having a thickness extending between the flat side of said sheet of resin and one of said lower resin surfaces;
applying one or more curative elements consisting of one or more curatives for said one or more thermosetting resins to said fibrous element, said curative elements being located on the second side of said fibrous element; and
curing said sheet of resin to form said composite part wherein said thickness of said resin bridges is such that said resin bridges flow during curing into said fibrous element in order to open the partially closed resin barrier zones to form a gas venting network which provides multi-dimensional escape of gas during curing of said sheet of resin.
2. A method for making a composite part according to claim 1 , wherein said step of applying one or more curative elements to fibrous element comprises applying a sheet of curative as a single entity, said sheet of curative comprising a flat side and a notched side, said flat side being located on the second side of said fibrous element and said notched side having alternating upper curative surfaces and lower curative surfaces; said sheet of curative comprising a plurality of curative elements consisting of parallel lines of one or more curatives for said thermosetting resins that are separated from each other by a curative barrier zone comprising a penetrable barrier material wherein said curative elements extend between the flat side of said sheet of curative and the upper curative surfaces, said sheet of curative further comprising curative bridges which extend across said curative barrier zones at the flat side of said sheet of curative to form partially closed curative barrier zones that are partially filled with said penetrable barrier material, said curative bridges providing connections between said curative elements along the flat side of said sheet of curative, said curative bridges consisting of one or more curatives for said thermosetting resins and each of said curative bridges having a thickness extending between the flat side of said sheet of curative and one of said lower curative surfaces, wherein said thickness of said curative bridges is such that said curative bridges flow during curing into said fibrous element in order to open the partially closed resin barrier zones to form a gas venting network which provides multi-dimensional escape of gas during curing of said sheet of resin.
3. A method for making a composite part according to claim 1 wherein said resin elements that are located on the first side of said fibrous element are transversely offset from the curative elements that are located on the second side of said fibrous element.
4. A method for making a composite part according to claim 2 wherein said resin elements that are located on the first side of said fibrous element are transversely offset from the curative elements that are located on the second side of said fibrous element.
5. A method for making a composite part according to claim 1 wherein said resin elements consist of one or more epoxy resins.
6. A method for making a composite part according to claim 1 wherein resin elements consisting of parallel lines of one or more thermosetting resins are also located on the second side of said fibrous element.
7. A method for making a prepreg according to claim 1 wherein curative elements consisting of parallel lines of one or more curatives are also located on the first side of said fibrous element.
8. A method for making a composite part according to claim 1 wherein the penetrable barrier material in said resin barrier zone comprises a material selected from the group consisting of gas, thermo-fusible polymers and porous materials.
9. A method for making a composite part according to claim 8 wherein the penetrable barrier material in said resin barrier zone comprises a gas.
10. A method for making a composite part according to claim 2 wherein the penetrable barrier material in said curative barrier zone comprises a material selected from the group consisting of gas, thermo-fusible polymers and porous materials.
11. A method for making a composite part according to claim 10 wherein the penetrable barrier material in said curative barrier zone comprises a gas.