US4063001A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing acid resistant glass fibers
Assignee: PPG Industries Inc
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Filing: 1976-05-13
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Granted: 1977-12-13
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Expires: 1996-05-13
Abstract
Abstract Acid resistant glass fibers are prepared by treating the surface of a siliceous glass fiber with an aqueous acid solution to increase the silica content thereof. The aqueous acid solution is removed from the surface of the glass fibers and the fibers are heated to dehydrate or partially dehydrate the surface. The glass fibers as produced have a dual composition; the outer surface of the fiber is rich in silica in relation to the core of the fiber. The fibers so formed are highly resistant to acid attack.
Inventors
- 👤 Isaac A. Zlochower
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:24
CPC Classifications
C; C03; C03C; C03C13/00; C03C13/005; C03C25/00; C03C25/66; C03C25/68; Y; Y10; Y10T; Y10T428/00; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
109 words
A method of preparing a dual composition, acid resistant glass fiber comprising contacting the surface of the siliceous glass fiber with an aqueous acidic solution at a pH and temperature and for a period of time sufficient to increase the silica content of said surface without substantially reducing the tensile strength of said fiber and producing a glass fiber having an overall SiO 2 content of 52 to 64 percent by weight, removing said aqueous acid solution from the surface of said fiber and heating the fiber after removing said acid solution for a time and at a temperature sufficient to render the surface of said fiber acid resistant.
Claim 2
Independent Claim
109 words
A method of preparing a dual composition, acid resistant glass fiber comprising contacting the surface of the siliceous glass fiber with an aqueous acidic solution at a pH and temperature and for a period of time sufficient to increase the silica content of said surface without substantially reducing the tensile strength of said fiber and producing a glass fiber having an overall SiO 2 content of 52 to 64 percent by weight, removing said aqueous acid solution from the surface of said fiber and heating the fiber after removing said acid solution for a time and at a temperature sufficient to render the surface of said fiber acid resistant.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said aqueous acid solution has a pH of 1 to 3.
Claim 4
Dependent Claim
11 words
A glass fiber produced according to the method of claim 2.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein said heating step is conducted at temperature between 300° F. and a temperature below the revitrification temperature of said fiber and is conducted for about 10 to about 60 minutes.
Claim 6
Dependent Claim
38 words
The method of claim 1 wherein the aqueous acid solution is selected from the group consisting of HCl, H 2 SO 4 , HNO 3 and acetic acid containing aqueous solutions having a pH of 1 to 2.2.
Claim 7
Dependent Claim
14 words
The method of claim 5 wherein the aqueous acid solutions contain ZnCl 2 .
Claim 8
Dependent Claim
16 words
The method of claim 5 wherein the aqueous acid solution contains Fe(NO 3 ) 3 .
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein the aqueous acid solution contains oxalic acid and Cr (NO 3 ) 3 .
Claim 10
Dependent Claim
35 words
The method of claim 1 wherein the heating step is conducted at temperature between 400° F. and a temperature below the revitrification temperature of said fiber and is conducted for 20 minutes to 60 minutes.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein said aqueous acid solution is a citric acid containing solution having a pH of 1 to 3.
Claim 12
Dependent Claim
34 words
The method of claim 1 wherein said heating step is at a temperature between 300° F. and below the revitrification temperature of said glass fiber and is conducted for between 10 to 60 minutes.
Claim 13
Dependent Claim
11 words
A glass fiber produced according to the method of claim 1.
References Cited (Backward Citations)
US2337460A
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US2461841A
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US2494259A
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US2686954A
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US3259517A
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US3687850A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |