Method of manufacturing composite panels

Abstract

A method of manufacturing solid composite panels utilizes an exothermic foam-forming resin to simultaneously consolidate and cure the heat activated resin of the composite panel without forming a foam-filled part. According to the method, composite fabric layers are laid up on the interior surface of a mold half that conforms to the surface configuration of the finished panel. Once the composite fabric layers are laid up, a flexible bladder is placed over the composite layup and the mold closed. The exothermic foam-forming resin is injected into the bladder within the mold cavity, which generates heat to cure the resin impregnated fabric layers above the cure temperature while simultaneously generating pressure within the cavity to consolidate the fabric layers into a substantially solid void-free composite panel.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to the fabrication of composite panels, more particularly to the manufacture of composite panels for use in medical equipment and residential construction. [0002] In U.S. Pat. No. 6,117,376 (the “376 patent”) the inventor of the present invention describes a method of making foam-filled composite products, in which fiber layers, impregnated with a heat activated resin are built up on two mold halves, which are then clamped together to form a pressure vessel. An exothermic foam-forming resin is then poured into the mold cavity. The exothermic foaming reaction of the foam material generates both heat and pressure to consolidate and cure the resin impregnated fiber layers while forming a tight bond between the foam and the fiber layers. Advantages of the method described in the '376 patent includes substantial savings in production costs by obviating the need for expensive autoclaves, vacuum furnaces, heated molds or othe...

AI Technical Summary

Benefits of technology

[0004] The present invention comprises a method of manufacturing solid composite panels utilizing an exothermic foam-forming resin to simultaneously consolidate and cure the heat activated resin of the composite panel without forming a foam-filled part. According to an illustrative embodiment of the present invention, composite fabric layers are laid up on the interior surface of a mold half that conforms to the surface configuration of the finished panel. The composite fabric layers may be so-called “pre-preg” sheets, which comprise fabric that has been pre-coated with resin, or they may be dry sheets that are wetted with resin after they have been placed in the mold half. Once the composite fabric layers are laid up, a flexible bladder is placed over the composite layup and the mold closed by means of a rigid cover plate so as to form a cavity inside the mold. A foam-forming resin, is pre-measured so as to expand to more than fill the cavity. The foam-forming resin is injected into the bladder within the mold cavity. The mix begins foaming after a short delay, generating an exothermic reaction that heats the resin impregnated fabric layers above the cure temperature. Simultaneously, the expand

Problems solved by technology

Unfortunately, to manufacture thin composite panels prior to the present invention, one had to resort to the capital equipment-intensive methods such as vacuum furnaces and autoclaves.

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