US4428992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of splicing reinforcement fiber
Assignee: HITCO A CORP OF CA
•
Filing: 1981-11-21
•
Granted: 1984-01-31
•
Expires: 2001-11-21
Abstract
Abstract Reinforcement fiber for fiber-reinforced resin composites such as graphite tows are spliced by applying a solution of a linear, soluble, high glass transition temperature polyimide having good thermal-oxidative stability to the broken ends of a fiber, placing the ends in contact and removing solvent. The preferred polyimide is an aromatic-cycloaliphatic diamine such as 5,(6)-amino-1-(4' amino phenyl)-1,3-trimethylindane (DAPI) imidized with a dianhydride such as PMDA or BTDA. The soluble polyimide can be preapplied to the fiber as a sizing. The splices are not apparent by visual inspection nor by instrumental scanning of cured composites indicating there is no blistering nor loss of strength.
Inventors
- 👤 Sidney W. Street
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:05
CPC Classifications
B; B65; B65H; B65H69/00; B65H69/02; B65H2701/00; B65H2701/30; B65H2701/31; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24132; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
111 words
A method of splicing a reinforcement fiber for reinforcing a composite with a matrix resin comprising the steps of applying to the ends of two of said fibers a solution of linear polyimide having a glass transition temperature of at least 200° C. dissolved in a fast evaporating solvent having a boiling point below 150° F.; said polyimide being insoluble in the solvent utilized to dissolve said matrix resin, having high heat resistance and being compatible with said matrix resin; placing the coated ends in contact; drying the solution to remove said fast evaporating solvent in less than one minute to form a continuous splice of said polyimide joining said ends.
Claim 2
Independent Claim
111 words
A method of splicing a reinforcement fiber for reinforcing a composite with a matrix resin comprising the steps of applying to the ends of two of said fibers a solution of linear polyimide having a glass transition temperature of at least 200° C. dissolved in a fast evaporating solvent having a boiling point below 150° F.; said polyimide being insoluble in the solvent utilized to dissolve said matrix resin, having high heat resistance and being compatible with said matrix resin; placing the coated ends in contact; drying the solution to remove said fast evaporating solvent in less than one minute to form a continuous splice of said polyimide joining said ends.
Claim 3
Dependent Claim
43 words
A method according to claim 1 in which the solution is applied to the fiber and dried to form a sizing and said splice is formed by dissolving the sizing adjacent broken ends of the fiber by applying said fast evaporating solvent thereto.
Claim 4
Dependent Claim
28 words
A method according to claim 1 in which the fast evaporating solvent is applied to the broken ends of the fiber before application of the solution of polyimide.
Claim 5
Dependent Claim
22 words
A method according to claim 1 in which the fiber is selected from carbon, graphite, fiberglass, boron, aromatic polyimide or polyvinyl alcohol.
Claim 6
Dependent Claim
14 words
A method according to claim 4 in which the fiber is graphite or carbon.
Claim 7
Dependent Claim
28 words
A method according to claim 4 in which the soluble polyimide is a linear polyimide having a glass transition temperature of at least 250° C. to 450° C.
Claim 8
Dependent Claim
24 words
A method according to claim 6 in which the solvent has a boiling point below 100° F. and evaporates in less than 10 seconds.
Claim 9
Dependent Claim
13 words
A method according to claim 7 in which the solvent is methylene chloride.
Claim 10
Dependent Claim
28 words
A method according to claim 1 further including the step of impregnation the splice-containing fiber with a matrix, reinforcement resin to form prepreg, filament wound or pultruded composites.
Claim 11
Dependent Claim
23 words
A method according to claim 9 in which the splice containing fiber is coated with reinforcement resin to form a sheet of prepreg.
Claim 12
Dependent Claim
39 words
A method according to claim 10 further including the steps of assembling a plurality of sheets of prepreg into an assembly and curing the matrix resin to form a fiber reinforced composite containing at least one of said splices.
Claim 13
Dependent Claim
30 words
A method according to claim 9 in which the matrix resin is selected from epoxy, polyimide or polyester resins and the matrix resin solvent is selected from ketones and alcohols.
Claim 14
Dependent Claim
21 words
A method according to claim 1 in which the polyimide is the polymerizate of an aromatic-cycloaliphatic diamine imidized with a dianhydride.
Claim 15
Dependent Claim
52 words
A method according to claim 13 in which the diamine is selected from compounds of the formula: ##STR2## where R 1 , R 2 and R 3 are individually selected from the group consisting of hydrogen, lower alkyl of 1 to 5 carbon atoms or alkoxy of 1 to 5 carbon atoms.
Claim 16
Dependent Claim
18 words
A method according to claim 14 in which the dianhydride is selected from benzophenonetetracarboxylic dianhydride or pyromellitic dianhydride.
Claim 17
Dependent Claim
12 words
A method according to claim 15 in which the diamine is 5,(6)-amino-1-(4'-aminophenyl)-1,3-trimethylindane.
Claim 18
Dependent Claim
22 words
A method according to claim 12 in which the splice is the same color as the matrix resin and is absent voids.
Claim 19
Dependent Claim
74 words
A fiber-reinforced resin matrix article comprising filamentary reinforcement fiber containing a splice formed by coating overlapped ends of the fiber with a linear, aromatic polyimide having a glass transition temperature of at least 200° C., said polyimide being dried from solution in a fast evaporating solvent having a boiling point less than 100° F., being insoluble in solvents for the matrix resin, having a high heat resistance and being compatible with said matrix resin.
Claim 20
Dependent Claim
74 words
A fiber-reinforced resin matrix article comprising filamentary reinforcement fiber containing a splice formed by coating overlapped ends of the fiber with a linear, aromatic polyimide having a glass transition temperature of at least 200° C., said polyimide being dried from solution in a fast evaporating solvent having a boiling point less than 100° F., being insoluble in solvents for the matrix resin, having a high heat resistance and being compatible with said matrix resin.
Claim 21
Dependent Claim
18 words
An article according to claim 18 in which the splice-containing fiber is embedded in a sheet of prepreg.
Claim 22
Dependent Claim
20 words
An article according to claim 19 in which said sheet of prepreg is contained in a cured fiber-reinforced resin composite.
Claim 23
Dependent Claim
18 words
An article according to claim 18 in which the polyimide is formed from imidization of an aromatic-cycloaliphatic diamine.
Claim 24
Dependent Claim
69 words
An article according to claim 18 in which the polyimide is a reaction product of a dianhydride selected from benzophenonetetracarboxylic dianhydride and pyromellitic dianhydride and the diamine is selected from compounds of the formula: ##STR3## where R 1 , R 2 and R 3 are individually selected from the group consisting of hydrogen, lower alkyl of 1 to 5 carbon atoms or alkoxy of 1 to 5 carbon atoms.
Claim 25
Dependent Claim
18 words
An article according to claim 20 in which the resin is selected from epoxy, polyimide and polyester resins.
References Cited (Backward Citations)
US469015A
Cited
US3070947A
Cited
US3386871A
Cited
US3607507A
Cited
US3665586A
Cited
US3904458A
Cited
US4028162A
Cited
US4077822A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |