US3972959A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing phenolic filaments
Assignee: Gun Ei Chemical Industry Co Ltd
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Filing: 1974-10-22
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Granted: 1976-08-03
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Expires: 1994-10-22
Abstract
Abstract A process for producing melt-spun and cured phenolic filaments having improved tenacity and whiteness which comprises treating cured phenolic filaments with an alcohol having 1 to 6 carbon atoms or acetone and reacting the thus-treated phenolic filaments with an esterifying solution containing acetic anhydride in the presence of an inorganic acid of phosphorus as an esterifying catalyst.
Inventors
- 👤 Hiroaki Koyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:36
CPC Classifications
D; D06; D06M; D06M13/00; D06M13/10; D06M13/144; D06M13/184; D06M13/1845
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
188 words
A process for producing melt-spun and cured phenolic filaments consisting essentially of a novolak resin in an amount of more than 50% by weight based on the total weight of the filaments and a fiber-forming thermoplastic synthetic resin in an amount of less than 50% by weight based on the total weight of the filaments and having improved tenacity and whiteness, which comprises contacting cured phenolic filaments with a treating agent in the vapor or liquid phase, said treating agent containing at least 25% by weight of at least one member selected from the group consisting of alcohols containing from 1 to 6 carbon atoms, acetone and mixtures thereof, the filaments being contacted with the treating agent before or during the drawing of the filaments, and reacting the thus-treated phenolic filaments with an esterifying solution containing at least 30% by weight of acetic anhydride as an esterifying agent and 0.3 to 20% by weight of an inorganic acid of phosphorus as an esterifying catalyst at a temperature of about 90° to 140° C. to esterify the phenolic hydroxyl or methylol groups of said novolak resin in the filaments.
Claim 2
Dependent Claim
188 words
A process for producing melt-spun and cured phenolic filaments consisting essentially of a novolak resin in an amount of more than 50% by weight based on the total weight of the filaments and a fiber-forming thermoplastic synthetic resin in an amount of less than 50% by weight based on the total weight of the filaments and having improved tenacity and whiteness, which comprises contacting cured phenolic filaments with a treating agent in the vapor or liquid phase, said treating agent containing at least 25% by weight of at least one member selected from the group consisting of alcohols containing from 1 to 6 carbon atoms, acetone and mixtures thereof, the filaments being contacted with the treating agent before or during the drawing of the filaments, and reacting the thus-treated phenolic filaments with an esterifying solution containing at least 30% by weight of acetic anhydride as an esterifying agent and 0.3 to 20% by weight of an inorganic acid of phosphorus as an esterifying catalyst at a temperature of about 90° to 140° C. to esterify the phenolic hydroxyl or methylol groups of said novolak resin in the filaments.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein said treating agent is an aqueous solution of methanol in a concentration of at least 25% by weight.
Claim 4
Dependent Claim
24 words
The process of claim 1 where said treating agent is an aqueous solution of methanol in a concentration of at least 35% by weight.
Claim 5
Dependent Claim
24 words
The process of claim 1 wherein said treating agent is an aqueous solution of methanol in a concentration of at least 50% by weight.
Claim 6
Dependent Claim
34 words
The process of claim 1 wherein the contacting of the cured phenolic filaments with the treating agent is performed at a temperature of about 30° to 70° C. for about 5 to 60 minutes.
Claim 7
Dependent Claim
23 words
The process of claim 1 wherein the concentration of the acetic anhydride in the esterifying solution is about 40 to 80% by weight.
Claim 8
Dependent Claim
23 words
The process of claim 1 wherein the concentration of the acetic anhydride in the esterifying solution is about 50 to 70% by weight.
Claim 9
Dependent Claim
18 words
The process of claim 1 wherein said inorganic acid of phosphorus in the esterifying solution is ortho-phosphoric acid.
Claim 10
Dependent Claim
25 words
The process of claim 1 wherein the concentration of the inorganic acid of phosphorus in the esterifying solution is about 0.6 to 10% by weight.
Claim 11
Dependent Claim
25 words
The process of claim 1 wherein the concentration of the inorganic acid of phosphorus in the esterifying solution is about 1 to 5% by weight.
Claim 12
Dependent Claim
28 words
The process of claim 1 wherein the esterification reaction is carried out at a temperature of 90° to 140° C. for a period of 1 to 60 minutes.
Claim 13
Dependent Claim
28 words
The process of claim 1 wherein the esterification reaction is carried out at a temperature of 100° to 130° C. for a period of 5 to 30 minutes.
Claim 14
Dependent Claim
41 words
The process of claim 1 wherein the cured phenolic filaments used as a starting material are cured filaments obtained by pre-treating uncured phenolic filaments using an acid catalyst and formaldehyde, and then curing the filaments using a basic catalyst and formaldehyde.
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) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |