US4003773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing graphite fibers of ultra-short length and narrow size distribution
Assignee: Hercules LLC
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Filing: 1976-03-02
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Granted: 1977-01-18
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Expires: 1996-03-02
Abstract
Abstract A process for cutting a multi-filament tow into fibers of ultra-short length and narrow size distribution is provided. Initially, a multi-filament tow is passed through a bath of liquid impregnating material at elevated temperature. The impregnated tow is then passed through a die which is sized to control the quantity of material impregnating the tow and to compact the filaments of the tow into a closely packed bundle. The resulting tow is then cooled to solidify the impregnating material and to convert the tow to a rigid form. The rigid tow is then cut, yielding wafer-thin disks. The impregnating material is then stripped from the wafer-thin disks with a solvent followed by removal of the solvent, thereby yielding fibers of ultra-short length and narrow size distribution.
Inventors
- 👤 Michael Anthony Grable
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:45
CPC Classifications
D; D01; D01G; D01G1/00; D01G1/02; D01G1/025; D01G1/027; B; B26; B26D; B26D7/00; B26D7/08; B26D7/10; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1052; Y10T83/00; Y10T83/04; Y10T83/0405; Y10T83/041
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
142 words
A method for preparing fibers of ultra-short length and narrow size distribution from multi-filament tow comprising the steps of: a. providing a source of multi-filament tow; b. passing said multi-filament tow through a bath of liquid impregnating material at elevated temperature, said impregnating material being one which is solid at ambient temperature; c. passing said impregnated tow through a die sized to control the quantity of material impregnating the tow and to compact the filaments of the tow into a closely packed bundle; d. cooling the compact tow to solidify the impregnating material therein and to convert the tow to a rigid form; e. cutting said rigid tow to produce wafer-thin disks therefrom; f. stripping the impregnating material from said wafer-thin disks with a solvent to yield fibers of ultra-short length and narrow size distribution; and g. removing solvent from the fibers.
Claim 2
Independent Claim
142 words
A method for preparing fibers of ultra-short length and narrow size distribution from multi-filament tow comprising the steps of: a. providing a source of multi-filament tow; b. passing said multi-filament tow through a bath of liquid impregnating material at elevated temperature, said impregnating material being one which is solid at ambient temperature; c. passing said impregnated tow through a die sized to control the quantity of material impregnating the tow and to compact the filaments of the tow into a closely packed bundle; d. cooling the compact tow to solidify the impregnating material therein and to convert the tow to a rigid form; e. cutting said rigid tow to produce wafer-thin disks therefrom; f. stripping the impregnating material from said wafer-thin disks with a solvent to yield fibers of ultra-short length and narrow size distribution; and g. removing solvent from the fibers.
Claim 3
Dependent Claim
14 words
A method according to claim 1 wherein the multi-filament tow consists of graphite filaments.
Claim 4
Dependent Claim
19 words
A method according to claim 1, wherein said multi-filament tow is passed through a bath containing heated paraffin wax.
Claim 5
Dependent Claim
31 words
A method according to claim 1, including the following additional step: passing the rigid tow of step (d) through a die, after cooling, whereby high spots or other malformations are removed.
Claim 6
Dependent Claim
46 words
A method according to claim 1, including the following additional step: passing the impregnated tow of step (c) through a second die, said second die having a discharge orifice larger than the discharge orifice of the die at step (c), to further shape the impregnated tow.
Claim 7
Dependent Claim
42 words
A method according to claim 1 wherein the impregnated tow of step (b) is passed through a cylindrical die sized to control the quantity of material impregnating the tow and to compact the filaments of the tow into a closely packed bundle.
Claim 8
Dependent Claim
38 words
A method according to claim 5, including the following additional step: passing the rigid tow of step (d) through a die, said die having a trimming edge whereby protrusions along the surface of the rigid tow are removed.
Claim 9
Dependent Claim
27 words
A method according to claim 7 wherein the multi-filament tow consists of graphite filaments and said multi-filament tow is passed through a bath containing heated paraffin wax.
References Cited (Backward Citations)
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Cited
US3549734A
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US3632366A
Cited
US3634570A
Cited
US3921874A
Cited
US3940464A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-18 | 1980-07-19 | 1981-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-18 | 1984-07-19 | 1985-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-18 | 1988-07-19 | 1989-01-18 | $7700.00 | Window Closed / Lapsed |