Curable prepregs possessing enhanced ability for the removal of gases from within prepregs and between prepreg plies in a prepreg layup prior to and/or during consolidation and curing. Each curable prepreg is a resin-impregnated, woven fabric that has been subjected to a treatment to create an array
Curable prepregs possessing enhanced ability for the removal of gases from within prepregs and between prepreg plies in a prepreg layup prior to and/or during consolidation and curing. Each curable prepreg is a resin-impregnated, woven fabric that has been subjected to a treatment to create an array of openings in at least one major surface. The location of the openings is specific to the weave pattern of the fabric. Furthermore, when these prepregs are laid up and subjected to a debulking process to form a composite part, a shorter debulking time can be achieved as compared to using prepregs without the same surface openings.
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1. A method for fabricating a composite part wherein an overall cure time is reduced as a result of a decrease in debulking time prior to curing, said method comprising: laying up a plurality of uncured prepregs to form a composite layup;debulking the composite layup to remove air and volatiles ther
1. A method for fabricating a composite part wherein an overall cure time is reduced as a result of a decrease in debulking time prior to curing, said method comprising: laying up a plurality of uncured prepregs to form a composite layup;debulking the composite layup to remove air and volatiles therefrom by: (a) sealing a vacuum bag over the composite layup; (b) drawing a vacuum from within said vacuum bag; (c) applying pressure external to the vacuum bag; and (c) continuing to draw vacuum and to apply pressurize for a predetermined time interval; andcuring the composite layup after debulking,wherein at least some of the uncured prepregs are porous prepregs with surface openings, each of said porous prepregs comprising:a woven fabric having two opposing faces and a weaving pattern in which one or more tows in a first weaving direction float over one or more tows in a second weaving direction, then pass under one or more tows in the second weaving direction,wherein a pocket is defined in the fabric surface when a first tow in the first weaving direction passes over a second tow in the second weaving direction then under an adjacent third tow in the second weaving direction, or when the first tow passes under a second tow in the second weaving direction then over an adjacent third tow in the second weaving direction, and the pocket location is defined by the portion of the first tow that is going up or going down between the adjacent second and third tows;a curable, hot-melt resin film covering one or both face(s) of the fabric and penetrating partially through the thickness of the fabric leaving an inner section of the fabric, in the thickness direction, substantially free of the resin film; andan array of openings in at least one of the resin films, each opening exposing at least a portion of the pocket in the fabric surface and configured to create a fluid flow path from the inner section of the fabric to at least one outer surface of the prepreg, or from at least one outer surface of the prepreg to the inner section, or from one outer surface of the prepreg to an opposite outer surface, or combination thereof. 2. The method of claim 1, wherein the weaving pattern of the woven fabric is satin weave or twill weave. 3. The method of claim 1, wherein the weaving pattern is satin weave, and the openings are formed through one or both surfaces of the prepreg. 4. The method of claim 1, wherein the hot-melt resin film is substantially solid at a temperature within the range of 20° C.-25° C. and becomes flowable at an elevated temperature below an onset curing temperature of the resin film. 5. The method of claim 1, wherein the hot-melt resin film comprises one or more thermoset resins as a major component, and is substantially free of any organic solvent. 6. The method of claim 1, wherein the hot-melt resin film comprises one or more epoxy resins, a curing agent, and at least one thermoplastic or elastomeric compound. 7. The method of claim 1, wherein each tow comprises a plurality of fiber filaments, which are formed of a material selected from: glass, carbon, aramid, polyethylene (PE), boron, quartz, basalt, ceramic, polyester, poly-p-phenylene-benzobisoxazole (PBO), and combinations thereof. 8. A method for fabricating a composite part wherein an overall cure time is reduced as a result of a decrease in debulking time prior to curing, said method comprising: laying up a plurality of uncured prepregs to form a composite layup;debulking the composite layup to remove air and volatiles therefrom by: (a) sealing a vacuum bag over the composite layup; (b) drawing a vacuum from within said vacuum bag; (c) applying pressure external to the vacuum bag; and (c) continuing to draw vacuum and to apply pressurize for a predetermined time interval; andcuring the composite layup after debulking,wherein at least some of the uncured prepregs are porous prepregs with surface openings, each of said porous prepregs comprising:a woven fabric having two opposing faces and a weaving pattern in which a tow in a first weaving direction passes over another tow in a second weaving direction, then pass under an adjacent tow in the second weaving direction, and interstices are defined between adjacent tows;a curable, hot-melt resin film covering one or both face(s) of the fabric and penetrating partially through the thickness of the fabric leaving an inner section of the fabric, in the thickness direction, substantially free of the resin film; andan array of openings in at least one of the resin films, each opening exposing an interstice in the fabric and configured to create a fluid flow path from the inner section of the fabric to at least one outer surface of the prepreg, or from at least one outer surface of the prepreg to the inner section, or from one outer surface of the prepreg to an opposite outer surface, or combination thereof. 9. The method of claim 8, wherein the weaving pattern of the woven fabric is plain weave. 10. The method of claim 9, wherein the openings are formed through opposing outer surfaces of the prepreg.
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이 특허에 인용된 특허 (5)
Guo Feng Xu ; Linas Repecka ; Steve Mortimer GB; Steve Peake ; Jack Boyd, Manufacture of void-free laminates and use thereof.
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