Patent US5094883A successfully refreshed from Google Patents.
US5094883A
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US
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Flexible multiply towpreg and method of production therefor
Assignee: Georgia Tech Research Corp
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Filing: 1989-04-17
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Granted: 1992-03-10
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Expires: 2009-04-17
Abstract
Abstract This invention relates to an improved flexible towpreg and a method of production therefor. The improved flexible towpreg comprises a plurality of towpreg plies which comprise reinforcing filaments and matrix forming material; the reinforcing filaments being substantially wetout by the matrix forming material such that the towpreg plies are substantially void-free composite articles, and the towpreg plies having an average thickness less than about 100 microns. The method of production for the improved flexible towpreg comprises the steps of spreading the reinforcing filaments to expose individually substantially all of the reinforcing filaments; coating the reinforcing filaments with the matrix forming material in a manner causing interfacial adhesion of the matrix forming material to the reinforcing filaments; forming the towpreg plies by heating the matrix forming material contacting the reinforcing filaments until the matrix forming material liquefies and coats the reinforcing filaments; and cooling the towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until the matrix forming material solidifies.
Inventors
- 👤 John D. Muzzy
- 👤 Babu Varughese
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:49
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/45; C04B41/4584; B; B29; B29B; B29B15/00; B29B15/08; B29B15/10; B29B15/12; B29C; B29C70/00; B29C70/04; B29C70/28; B29C70/40; B29C70/50; D; D01; D01F; D01F11/00; D01F11/10; D01F11/14; D01F11/16; D06; D06M; D06M23/00; D06M23/08; B29K; B29K2105/00; B29K2105/25; B29K2105/251; Y; Y10; Y10S; Y10S428/00; Y10S428/902
Claims Analysis
Total Claims: 72
Claim 1
Independent Claim
125 words
A method for the production of an improved flexible towpreg comprising a plurality of towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, comprising the steps of: (a) spreading said reinforcing filaments to expose individually substantially all of said reinforcing filaments in a generally columnated manner; (b) coating said reinforcing filaments with said matrix forming material in a manner causing interfacial adhesion of said matrix forming material to said reinforcing filaments; (c) forming said towpreg plies by heating said matrix forming material contacting said reinforcing filaments until said matrix forming material liquefies and coats said reinforcing filaments; and (d) cooling said towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until said matrix forming material solidifies.
Claim 2
Independent Claim
125 words
A method for the production of an improved flexible towpreg comprising a plurality of towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, comprising the steps of: (a) spreading said reinforcing filaments to expose individually substantially all of said reinforcing filaments in a generally columnated manner; (b) coating said reinforcing filaments with said matrix forming material in a manner causing interfacial adhesion of said matrix forming material to said reinforcing filaments; (c) forming said towpreg plies by heating said matrix forming material contacting said reinforcing filaments until said matrix forming material liquefies and coats said reinforcing filaments; and (d) cooling said towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until said matrix forming material solidifies.
Claim 3
Dependent Claim
12 words
The method as claimed in claim 1, wherein said spreading is lateral.
Claim 4
Dependent Claim
18 words
The method as claimed in claim 1, wherein said spreading results in a band one reinforcing filament thick.
Claim 5
Dependent Claim
23 words
The method as claimed in claim 1, wherein said spreading of said reinforcing filaments is maintained by axial tension on said reinforcing filaments.
Claim 6
Dependent Claim
13 words
The method as claimed in claim 4, wherein said axial tension is constant.
Claim 7
Dependent Claim
22 words
The method as claimed in claim 1, wherein said matrix forming material is in powder form when contacted with said reinforcing filaments.
Claim 8
Dependent Claim
26 words
The method as claimed in claim 6, wherein said powder comprises particles whose average diameter is greater than twice the average diameter of said reinforcing filaments.
Claim 9
Dependent Claim
27 words
The method as claimed in claim 6, wherein said powder comprises particles whose average diameter is greater than four times the average diameter of said reinforcing filaments.
Claim 10
Dependent Claim
21 words
The method as claimed in claim 1, wherein said matrix forming material liquefies and solidifies in less than about 60 seconds.
Claim 11
Dependent Claim
60 words
The method as claimed in claim 1, wherein said matrix forming material is selected from the group consisting of ABS group, acetals, acrylics, alkyd polyesters, allyls, aminos, epoxies, fluoroplastics, furans, melamines, nylons, phenolics, phenylene oxides and ethers, polyamides, polyamide-imides, polybutylenes, polycarbonates, polyesters, polyetheretherketones (PEEK), polyetherimides, polyethylenes, polyimides, polymethylpentenes, polyphenylene sulfides, polypropylenes, polystyrenes, polyurethanes, sulfones, ureas and vinyls, and blends thereof.
Claim 12
Dependent Claim
19 words
The method as claimed in claim 1, wherein said filaments have an average diameter no greater than 25 microns.
Claim 13
Dependent Claim
12 words
The method as claimed in claim 1, wherein said filaments are continuous.
Claim 14
Dependent Claim
19 words
The method as claimed in claim 1, wherein said filaments have a glass transition temperature greater than ambient temperature.
Claim 15
Dependent Claim
18 words
The method as claimed in claim 1, wherein said filaments have a melting temperature greater than ambient temperature.
Claim 16
Dependent Claim
23 words
The method as claimed in claim 1, wherein said filaments have a melting temperature more than the consolidation temperature of the resulting towpreg.
Claim 17
Dependent Claim
13 words
The method as claimed in claim 1, wherein said filaments are electrically grounded.
Claim 18
Dependent Claim
30 words
The method as claimed in claim 1, wherein said filament is selected from the group consisting of glass fibers, carbon fibers, graphite fibers, organic fibers, ceramic fibers, and hybrid fibers.
Claim 19
Dependent Claim
32 words
The method as claimed in claim 17, wherein said organic fiber is selected from the group consisting of liquid crystal fibers such as aramids and aromatic polyesters which are not low melting.
Claim 20
Dependent Claim
14 words
The method as claimed in claim 17, wherein said ceramic fiber is silicon carbide.
Claim 21
Dependent Claim
24 words
The method as claimed in claim 17, wherein said hybrid fiber is selected from the group consisting of aramid/carbon, aramid/glass, aramid/carbon/glass, and carbon/glass fibers.
Claim 22
Dependent Claim
25 words
The method as claimed in claim 1, wherein said heating occurs at a temperature significantly higher than the melting temperature of said matrix forming material.
Claim 23
Dependent Claim
29 words
The method as claimed in claim 21, wherein said heating occurs at a temperature which is as high as said matrix forming material will take without incurring degrading reaction.
Claim 24
Dependent Claim
29 words
The method as claimed in claim 21, wherein said heating occurs at a temperature which is as high as said matrix forming material will take without incurring resin advancement.
Claim 25
Dependent Claim
19 words
The method as claimed in claim 21, 22, or 23, wherein said heating occurs for less than 60 seconds.
Claim 26
Dependent Claim
18 words
The method as claimed in claim 1, wherein said filaments are split from each other during step (d).
Claim 27
Dependent Claim
17 words
The method as claimed in claim 25, wherein said filaments are split from each other before cooling.
Claim 28
Dependent Claim
18 words
The method as claimed in claim 25, wherein said filaments are split from each other by mechanical means.
Claim 29
Dependent Claim
13 words
The method as claimed in claim 1, wherein multiple towpreg plies are produced.
Claim 30
Dependent Claim
17 words
The method as claimed in claim 28, wherein said plies contain a plurality of said reinforcing filaments.
Claim 31
Dependent Claim
19 words
The method as claimed in claim 29, wherein said reinforcing filaments are substantially wetout by said matrix forming material.
Claim 32
Dependent Claim
19 words
The method as claimed in claim 1, wherein said plies have an average length greater than their average width.
Claim 33
Dependent Claim
19 words
The method as claimed in claim 1, wherein said plies have an average width greater than their average thickness.
Claim 34
Dependent Claim
19 words
The method as claimed in claim 31, wherein said average length is at least about 30 times said width.
Claim 35
Dependent Claim
23 words
The method as claimed in claim 28, wherein the matrix forming material content of said towpreg plies is more than 25% by volume.
Claim 36
Dependent Claim
22 words
The method as claimed in claim 28, wherein said towpreg plies have an average ply thickness of less than about 100 microns.
Claim 37
Dependent Claim
22 words
The method as claimed in claim 28, wherein said towpreg plies have an average ply thickness of less than about 75 microns.
Claim 38
Dependent Claim
24 words
The method as claimed in claim 28, wherein said towpreg plies have an average ply thickness of between about 10 and about 50 microns.
Claim 39
Dependent Claim
24 words
The method as claimed in claim 28, wherein said towpreg plies have an average ply thickness of between about 15 and about 30 microns.
Claim 40
Independent Claim
107 words
A method for the production of an improved flexible towpreg comprising a plurality of towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, comprising the steps of; (a) supplying a quantity of tow comprising a plurality of said reinforcing filaments; (b) spreading said tow so as to form a generally columnated lateral spread of said reinforcing filaments; (c) coating said reinforcing filaments with said matrix forming material; (d) liquefying said matrix forming material on said reinforcing filaments to produce a substantially wetout tow; (e) splitting said coated reinforcing filaments from each other; and (f) cooling said coated reinforcing filaments to produce said towpreg plies.
Claim 41
Independent Claim
107 words
A method for the production of an improved flexible towpreg comprising a plurality of towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, comprising the steps of; (a) supplying a quantity of tow comprising a plurality of said reinforcing filaments; (b) spreading said tow so as to form a generally columnated lateral spread of said reinforcing filaments; (c) coating said reinforcing filaments with said matrix forming material; (d) liquefying said matrix forming material on said reinforcing filaments to produce a substantially wetout tow; (e) splitting said coated reinforcing filaments from each other; and (f) cooling said coated reinforcing filaments to produce said towpreg plies.
Claim 42
Dependent Claim
23 words
The method as claimed in claim 39, wherein groups of said coated reinforcing filaments form said towpreg plies during said cooling step (f).
Claim 43
Dependent Claim
24 words
The method as claimed in claim 39, wherein said tow is maintained in axial tension to prevent said reinforcing filaments from collapsing upon themselves.
Claim 44
Dependent Claim
13 words
The method as claimed in claim 41, wherein said axial tension is constant.
Claim 45
Dependent Claim
12 words
The method as claimed in claim 39, said tow is suppied untwisted.
Claim 46
Dependent Claim
14 words
The method as claimed in claim 39, wherein said reinforcing, filaments are electrically grounded.
Claim 47
Dependent Claim
21 words
The method as claimed in claim 1 or 39, wherein said coating is accomplished by an electrostatic fluidized bed coating means.
Claim 48
Dependent Claim
20 words
The method as claimed in claim 1 or 39, wherein said coating is accomplished by a wet powder coating means.
Claim 49
Dependent Claim
20 words
The method as claimed in claim 1 or 39, wherein said coating is accomplished by a hot melt coating means.
Claim 50
Dependent Claim
19 words
The method as claimed in claim 1 or 39, wherein said coating is accomplished by a solution coating means.
Claim 51
Dependent Claim
26 words
The method as claimed in claim 1 or 39, wherein including a step for desizing said reinforcing filaments between said spreading step and said coating step.
Claim 52
Dependent Claim
29 words
The method as claimed in claim 1 or 39, further including a step for applying adhesion promoters to said reinforcing filaments between said spreading step and said coating step.
Claim 53
Dependent Claim
28 words
The method as claimed in claim 1 or 39 further including a step for surface activation of said reinforcing filaments between said spreading step and said coating step.
Claim 54
Dependent Claim
67 words
The method as claimed in claim 45, wherein: said matrix forming material is uniformly dispersed in the fluidized bed of said electrostatic fludized bed coating means; the voltage employed in said electrostatic fluidized bed coating means is from about 0 to about 100 kilovolts; and the air input to said electrostatic fluidized bed coating means is from about 0 to about 12.5 standard cubic feet per minute.
Claim 55
Dependent Claim
22 words
The method as claimed in claim 52, wherein said air is cleaned and dried prior to entering said electrostatic fluidized bed means.
Claim 56
Dependent Claim
74 words
The method as claimed in claim 52, wherein: matrix of polyester powders is at about 50 kV or less; matrix forming material consisting essentially of epoxy powders is electrically charged at between about 40 and about 70 kV; matrix forming material consisting essentially of vinyl powders is at between about 60 and about 75 kV; and matrix forming material consisting essentially of PEEK is electrically charged at between about 70 and about 90 kV.
Claim 57
Dependent Claim
32 words
The method as claimed in claim 46, wherein said wet powder coating means is a slurry coating means comprising a roll coater, a wet powder reservoir, a slurry pump, and a drier.
Claim 58
Dependent Claim
20 words
The method as claimed in claim 55, wherein said wet powder comprises matrix forming material, water, and a water-soluble binder.
Claim 59
Dependent Claim
21 words
The method as claimed in claim 55, wherein said wet powder comprises matrix forming material, a solvent, and a solvent-soluble binder.
Claim 60
Dependent Claim
15 words
The method as claimed in claim 56, wherein said water is evaporated in said drier
Claim 61
Dependent Claim
15 words
The method as claimed in claim 57, wherein said solvent is evaporated in said drier.
Claim 62
Dependent Claim
17 words
The method as claimed in claim 55, wherein said reinforcing filaments are drawn directly through said slurry.
Claim 63
Dependent Claim
21 words
The method as claimed in claim 47, wherein said hot melt means comprises a roll coater and a hot melt reservoir.
Claim 64
Dependent Claim
22 words
The method as claimed in claim 47, wherein said hot melt means comprises an extruder and die and a hot melt reservoir.
Claim 65
Dependent Claim
17 words
The method as claimed in claim 47, wherein said hot melt means comprises a hot melt reservoir.
Claim 66
Dependent Claim
12 words
The method as claimed in claim 62, wherein said die is grooved.
Claim 67
Dependent Claim
21 words
The method as claimed in claim 48, wherein said solution coating means comprises a solution reservoir, a drier, and a melter.
Claim 68
Dependent Claim
19 words
the method as claimed in claim 65, wherein said solution comprises said matrix forming material dissolved in a solvent.
Claim 69
Dependent Claim
39 words
The method as claimed in claim 66, wherein said reinforcing filaments are first drawn through said solution reservoir so as to coat said reinforcing filaments, then said coated reinforcing filaments are passed through said drier to evaporate said solvent.
Claim 70
Dependent Claim
18 words
The method as claimed in claim 1 or 39, further comprising a gathering step as the final step.
Claim 71
Dependent Claim
19 words
The method as claimed in claim 1 or 39, further comprising a polishing step subsequent to said coating step.
Claim 72
Dependent Claim
19 words
The method as claimed in claim 61, wherein said polishing step is accomplished by a plurality of polishing rollers.
References Cited (Backward Citations)
US4714642A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-10 | 1995-09-09 | 1996-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-10 | 1999-09-09 | 2000-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-10 | 2003-09-09 | 2004-03-10 | $7700.00 | Window Closed / Lapsed |