Method for preparing preforms for molding processes
AssigneeThe Dow Chemical Company
InventorsHenry G. Heck, Warren D. White
Life of this patent
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Abstract
Preforms for molding processes such as resin transfer molding processes are prepared by melting a solid, non-sintering, thermoplastic-like resinous compound on the surface of a substrate material; after cooling, assembling one or more plies of the coated substrate material into the desired shape; heating the thus shaped substrate material to a temperature above the melting temperature of resinous compound and subsequently cooling to a temperature below the melting point of the resinous compound.
Claims7
A method for preparing preforms which comprises (1) applying substantially evenly onto the surface of each of one or more plys of an unimpregnated substrate material one or more non-sintering thermoplastic-like resinous compounds which are substantially free of any compound which would serve as a crosslinker for said thermoplastic-like, solid resinous compound, said resinous compound being in the form of a powder having a particle size of less than about 500 microns and having a melting point of from about 50.degree. C. to about 70.degree. C. in an amount of from about 2 to about 12 percent by weight based upon the weight of said substrate material;
- (2) fusing said powdered thermoplastic-like resinous compound into a film on the surface of said substrate material:
- (3) cooling said resinous material:
- (4) assembling one or more plies of the thus treated substrate material and conforming said plies of said treated substrate material into a desired shape:
- (5) subjecting the thus shaped plies of treated substrate material at a temperature sufficient to melt said resinous compound;
- and (6) cooling said shaped treated plies of substrate material to a temperature below the melting point of said resinous compound;
- thereby forming a preshaped preform for use in molding processes as reinforcing material.
Dependencies are inferred from the claim text.