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US 5,427,725 AGranted
Process for resin transfer molding and preform used in the process
AssigneeThe Dow Chemical Company
InventorsWarren D. White, Phil H. Cook, Martin Wai, William Davis
Life of this patent
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Abstract
An improved process to make composites contains the steps of: (1) partially curing a tackifier resin in contact with a substrate to form a shapeable preform; (2) adding a matrix resin and co-curing the tackifier and matrix resin to form a composite. The resulting composites are useful in structural applications.
Claims18
A process to make a matrix composite comprising the steps of:
- (1) contacting a reinforcing substrate with a tackifier, which contains either:
- (a) a single resin that is capable of at least partially curing with itself;
- or (b) a mixture containing resin and hardener that is capable of at least partially curing, at a temperature and for a time sufficient to partially cure the tackifier so that it adheres to the substrate but remains thermoplastic-like and capable of further reaction, whereby a preform is made;
- (2) placing one or more layers of the preform in a mold;
- (3) injecting a second curable resin or resin composition, that is capable of reacting with the tackifier, into the mold to impregnate the preform;
- and
- (4) curing the tackifier and matrix resin, whereby a composite is formed.
4 more elements
An improved method to make composites having the steps of:
- (1) contacting a fiber-containing reinforcing substrate with a tackifier, which is a first curable resin or resin composition, at a temperature selected such that the tackifier binds fibers within the substrate together but remains capable of further reaction, whereby a preform is made;
- and
- (2) impregnating one or more preforms with a matrix resin, which is a second curable resin or resin composition that is capable of reacting with the tackifier;
- and
- (3) curing the tackifier and matrix resin, whereby a composite is formed, comprising the improvement that:
- (a) the tackifier contains a labeling moiety that can be quantitatively analyzed after the composite is formed without destroying the composite;
- and
- (b) the quantity of labeling moiety is analyzed by non-destructive methods in at least two different points of the composite during or after Step (2).
5 more elements
Dependencies are inferred from the claim text.