US3723588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for production of novolac fibers
Assignee: Unifrax I LLC
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Filing: 1970-11-04
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Granted: 1973-03-27
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Expires: 1990-11-04
Abstract
Abstract A novolac melt is fiberized to produce a thermoplastic, uncured novolac fiber, and the novolac is curved by heating the fiber in a formaldehyde environment in the presence of an acid catalyst to obtain an infusible, cured novolac fiber.
Inventors
- 👤 J Economy
- 👤 R Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:20
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/58; D01F6/76
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
22 words
A method as set forth in claim 1 wherein said melt is fiberized by blowing a thin falling stream of said melt.
Claim 2
Dependent Claim
19 words
A method as set forth in claim 1 wherein said melt is fiberized by drawing it through an orifice.
Claim 3
Dependent Claim
23 words
A method as set forth in claim 3 wherein said melt has a viscosity of from about 5,000 cps to about 70,000 cps.
Claim 4
Dependent Claim
23 words
A method as set forth in claim 3 wherein said melt has a viscosity of from about 20,000 cps to about 50,000 cps.
Claim 5
Dependent Claim
16 words
A method as set forth in claim 1 wherein said novolac is a phenol formaldehyde novolac.
Claim 6
Dependent Claim
22 words
A method as set forth in claim 1 wherein said acid is present in said uncured novolac fiber in a catalytic quantity.
Claim 7
Dependent Claim
26 words
A method as set forth in claim 1 wherein said uncured novolac fiber is cured by heating it in a solution of formaldehyde and an acid.
Claim 8
Dependent Claim
21 words
A method as set forth in claim 8 wherein said solution is an aqueous solution and said acid is hydrogen chloride.
Claim 9
Dependent Claim
30 words
A method as set forth in claim 9 wherein said formaldehyde and said hydrogen chloride are each present in an amount of from about 12 percent to about 18 percent.
Claim 10
Dependent Claim
38 words
A method as set forth in claim 1 wherein said uncured novolac fiber is cured by heating it in a gaseous atmosphere containing an acid and from about 10 percent to about 99 percent by volume of formaldehyde.
Claim 11
Dependent Claim
14 words
A method as set forth in claim 11 wherein said acid is hydrogen chloride.
Claim 12
Dependent Claim
24 words
A method as set forth in claim 1 including the step of further curing said infusible fiber by heating it in a nonoxidizing atmosphere.
Claim 13
Dependent Claim
13 words
A method as set forth in claim 13 wherein said atmosphere is nitrogen.
Claim 14
Dependent Claim
14 words
A method as set forth in claim 13 wherein said atmosphere is a vacuum.
Claim 15
Dependent Claim
122 words
A method for the production of an infusible, cured novolac fiber according to claim 1 wherein said novolac is a phenol formaldehyde novolac, said melt has a viscosity of from about 5, 000 cps to about 70,000 cps, and said melt is fiberized by drawing it through an orifice to form an uncured novolac fiber having a diameter of from less than about 4 microns to about 300 microns, curing said uncured novolac fiber by heating it in an aqueous solution containing at least about 1 percent each of formaldehyde and an acid to render said fiber infusible, and further curing the resulting infusible fiber by heating it in a non-oxidizing atmosphere selected from the group consisting of nitrogen and a vacuum.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |