US3894884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the enhancement of low modulus carbon fibers
Assignee: Celanese Corp
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Filing: 1972-08-28
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Granted: 1975-07-15
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Expires: 1992-08-28
Abstract
Abstract An improved process is provided for modifying the surface characteristics of a low modulus carbonaceous fibrous material to facilitate enhanced adhesion between the fibrous material and a resinous matrix material. The process is carried out in the absence of electrolysis by contacting the carbonaceous fibrous material for a relatively brief residence time with an aqueous solution of sodium hypochlorite (as defined) which is provided at a moderate temperature, and thereafter washing the same. Composite articles of enhanced interlaminar shear strength may be formed by incorporating the fibers modified in accordance with the present process in a resinous matrix material.
Inventors
- 👤 Melvin L Druin
- 👤 Robert Dix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:11
CPC Classifications
D; D01; D01F; D01F11/00; D01F11/10; D01F11/12; D01F11/122; D01F11/121; D01F11/14; D01F9/00; D01F9/08; D01F9/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
114 words
AN IMPROVED PROCESS FO ENHANCING THE ABILITY OF A CARBONACEOUS FIBROUS MATERIAL CONTAINING AT LEAST ABOUT 90 PER CENT CARBON BY WEIGHT AND EXHIBITING A MEAN SINGLE FILAMENT YOUNG,S MODULES OF ABOUT 10 TO 50 MILLION PSI TO BOND TO A RESINOUS MATRIX MATERIAL COMPRISING: A. CONTACTING SAID FIBROUS MATERIAL FOR ABOUT 1 TO 60 MINUTES IN THE ABSENCE OF ELECTROLYSIS WITH AN AQUEOUS SOLUTION OF SODIUM HYDROCHLORITE PROVIDED AT ABOUT 20* TO 35*C. HAVING A PH OF ABOUT 8 TO 12 AND AN ACTIVE CHLORIN CONCENTRATION OF ABOUT 3 TO 7 PER CENT BY WEIGHT, B. WASHING THE RESULTING CARBONACEOUS FIBROUS MATERIAL TO REMOVE. RESIDUAL SOLUTION ADHERNG THE SAME, AND C. DRYING SAME
Claim 2
Dependent Claim
114 words
AN IMPROVED PROCESS FO ENHANCING THE ABILITY OF A CARBONACEOUS FIBROUS MATERIAL CONTAINING AT LEAST ABOUT 90 PER CENT CARBON BY WEIGHT AND EXHIBITING A MEAN SINGLE FILAMENT YOUNG,S MODULES OF ABOUT 10 TO 50 MILLION PSI TO BOND TO A RESINOUS MATRIX MATERIAL COMPRISING: A. CONTACTING SAID FIBROUS MATERIAL FOR ABOUT 1 TO 60 MINUTES IN THE ABSENCE OF ELECTROLYSIS WITH AN AQUEOUS SOLUTION OF SODIUM HYDROCHLORITE PROVIDED AT ABOUT 20* TO 35*C. HAVING A PH OF ABOUT 8 TO 12 AND AN ACTIVE CHLORIN CONCENTRATION OF ABOUT 3 TO 7 PER CENT BY WEIGHT, B. WASHING THE RESULTING CARBONACEOUS FIBROUS MATERIAL TO REMOVE. RESIDUAL SOLUTION ADHERNG THE SAME, AND C. DRYING SAME
Claim 3
Dependent Claim
39 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material in accordance with claim 1 wherein said fibrous material is immersed in said solution of sodium hypochlorite during said contact.
Claim 4
Dependent Claim
53 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material in accordance with claim 1 wherein said aqueous solution of sodium hypochlorite has a pH of about 10.5 to 11.5 and an active chlorine concentration of about 5.025 to 5.35 per cent by weight.
Claim 5
Dependent Claim
68 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material according to claim 1 wherein said washing is conducted at least in part by contacting said resulting carbonaceous fibrous material with a solution of a mineral acid to neutralize any adhering residue resulting from said contact with said sodium hypochlorite solution, and by subsequently rinsing the same with water.
Claim 6
Dependent Claim
112 words
An improved process for enhancing the ability of a carbonaceous fibrous material containing at least about 95 per cent carbon by weight and exhibiting a mean single filament Young''s modulus of about 20 to 40 million psi to bond to a resinous matrix material comprising: a. contacting said fibrous material for about 2 to 45 minutes in the absence of electrolysis in an aqueous solution of sodium hypochlorite provided at about 20* to 35*C. having a pH of about 10.5 to 11.5 and an active chlorine concentration of about 5.025 to 5.35 per cent by weight, b. washing the resulting carbonaceous fibrous material to remove residual solution, and c. drying the same.
Claim 7
Dependent Claim
112 words
An improved process for enhancing the ability of a carbonaceous fibrous material containing at least about 95 per cent carbon by weight and exhibiting a mean single filament Young''s modulus of about 20 to 40 million psi to bond to a resinous matrix material comprising: a. contacting said fibrous material for about 2 to 45 minutes in the absence of electrolysis in an aqueous solution of sodium hypochlorite provided at about 20* to 35*C. having a pH of about 10.5 to 11.5 and an active chlorine concentration of about 5.025 to 5.35 per cent by weight, b. washing the resulting carbonaceous fibrous material to remove residual solution, and c. drying the same.
Claim 8
Dependent Claim
38 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material according to claim 5 wherein said fibrous material is immersed in said solution of sodium hypochlorite during said contact.
Claim 9
Dependent Claim
43 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material in accordance with claim 5 wherein said fibrous material is contacted with said aqueous solution of sodium hypochlorite for about 4 to 30 minutes.
Claim 10
Dependent Claim
36 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material in accordance with claim 5 wherein said aqueous solution of sodium hypochlorite is provided at about 25*C.
Claim 11
Dependent Claim
69 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material in accordance with claim 5 wherein said washing is conducted at least in part by contacting said resulting carbonaceous fibrous material with a solution of a mineral acid to neutralize any adhering residue resulting from said contact With said sodium hypochlorite solution, and by subsequently rinsing the same with water.
Claim 12
Dependent Claim
137 words
An improved process for enhancing the ability of a carbonaceous fibrous material containing at least about 95 per cent carbon by weight and exhibiting a mean single filament Young''s modulus of about 20 to 40 million psi to bond to a resinous matrix material comprising: a. contacting said fibrous material for about 4 to 30 minutes in the absence of electrolysis in an aqueous solution of sodium hypochlorite provided at about 25*C. having a pH of about 11 and an active chlorine concentration of about 5.25 per cent by weight, b. rinsing the resulting carbonaceous fibrous material with water, c. contacting the previously rinsed carbonaceous fibrous material with a dilute aqueous solution of a mineral acid to neutralize said sodium hypochlorite adhering thereto, d. subsequently rinsing the carbonaceous fibrous material with water, and e. drying the same.
Claim 13
Dependent Claim
137 words
An improved process for enhancing the ability of a carbonaceous fibrous material containing at least about 95 per cent carbon by weight and exhibiting a mean single filament Young''s modulus of about 20 to 40 million psi to bond to a resinous matrix material comprising: a. contacting said fibrous material for about 4 to 30 minutes in the absence of electrolysis in an aqueous solution of sodium hypochlorite provided at about 25*C. having a pH of about 11 and an active chlorine concentration of about 5.25 per cent by weight, b. rinsing the resulting carbonaceous fibrous material with water, c. contacting the previously rinsed carbonaceous fibrous material with a dilute aqueous solution of a mineral acid to neutralize said sodium hypochlorite adhering thereto, d. subsequently rinsing the carbonaceous fibrous material with water, and e. drying the same.
Claim 14
Dependent Claim
38 words
An improved process for enhancing the ability of a carbonaceous fibrous material to bond to a resinous matrix material according to claim 10 wherein said fibrous material is immersed in said solution of sodium hypochlorite during said contact.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |