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US 11,390,060 B2Granted
Surface treatment to enhance bonding of composite materials
AssigneeCytec Industries Inc.
InventorsJessica L. Wallick, Leonard A. MacAdams
Life of this patent
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Abstract
A method for surface preparation of composite substrates prior to adhesive bonding. A curable surface treatment layer containing blocked isocyanate compounds is applied onto a curable composite substrate, followed by co-curing. The surface treatment layer may be a resin layer without fibers or a removal peel ply composed of resin-impregnated fabric. After surface preparation, the composite substrate is provided with a chemically-active, bondable surface that can be adhesively bonded to another composite substrate to form a covalently-bonded structure.
Claims20
A method for surface preparation prior to adhesive bonding comprising:
- (a) providing a composite substrate comprising reinforcing fibers impregnated with a curable matrix resin, said curable matrix resin comprising one or more epoxy resins and a curing agent;
- (b) applying a surface treatment layer onto a surface of the composite substrate, said surface treatment layer comprising one or more epoxy resins and blocked isocyanate compounds;
- (c) co-curing the composite substrate and the surface treatment layer at an elevated temperature for a time period to unblock some, but not all, of the blocked isocyanate compounds,
- wherein the blocked isocyanate compounds are non-reactive at 20° C.-25° C.
1 more element
A bonding method comprising:
- (a) providing a first composite substrate comprising reinforcing fibers impregnated with a first curable matrix resin, said first curable matrix resin comprising one or more epoxy resins and a curing agent;
- (b) applying a surface treatment layer onto a surface of the first composite substrate, said surface treatment layer comprising one or more epoxy resins and blocked isocyanate compounds, wherein the blocked isocyanate compounds are non-reactive at 20° C.-25° C.;
- (c) co-curing the first composite substrate and the surface treatment layer at an elevated temperature for a time period to unblock some, but not all, of the blocked isocyanate compounds, wherein the first composite substrate is fully cured or partially cured after co-curing,
- (d) joining the fully cured or partially cured first composite substrate having the surface treatment layer thereon to a second composite substrate with a curable adhesive film in between the composite substrates and the surface treatment layer adjacent to the curable adhesive film, and
- (e) curing the joined composite substrates to form a covalently bonded structure, wherein the blocked isocynate compounds in the surface treatment layer become unblocked during curing at (e).
2 more elements
A bonding method comprising:
- (a) providing a first composite substrate comprising reinforcing fibers impregnated with a first curable curable resin, said first curable matrix resin comprising one or more epoxy resins and a curing agent;
- (b) applying a curable peel ply onto a surface of the first composite substrate, said peel ply comprising a woven fabric embedded in a second curable resin, wherein the second curable resin comprises one or more epoxy resins and blocked isocyanate compounds;
- (c) co-curing the first composite substrate and the peel ply at an elevated temperature for a time period to unblock some, but not all, of the blocked isocyanate compounds, wherein the second curable resin is partially cured after co-curing;
- (d) removing most of the peel ply, including the woven fabric therein, from the first composite substrate, leaving behind a remaining film of partially cured thermoset material comprising blocked isocyanate compounds on the first composite substrate;
- (e) joining the first composite substrate to a second composite substrate with a curable adhesive film in between the composite substrates, wherein the remaining film of partially cured thermoset material is adjacent to the curable adhesive film, and
- (f) curing the joined composite substrates to form a covalently bonded structure, wherein the blocked isocyanate compounds in the remaining film of partially cured thermoset material become unblocked during curing at (f).
3 more elements
Dependencies are inferred from the claim text.