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US3639140A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for carbonized cellulose fiber or the products thereof

Assignee: Nitto Boseki Co Ltd
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Filing: 1969-10-03
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Granted: 1972-02-01
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Expires: 1989-10-03
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Abstract

Abstract Cellulose fiber or the product thereof is treated with a strength increasing agent selected from the group consisting of (A) ammonium sulfate, ammonium bisulfate, ammonium sulfite, ammonium bisulfite, ammonium thiosulfate, ammonium sulfamate, ammonium imidosulfonate, and mixtures thereof; (B) a mixture of at least one compound selected from the group consisting of ammonium sulfate, ammonium bisulfate, ammonium sulfite, ammonium bisulfite, ammonium thiosulfate, ammonium sulfamate, and ammonium imidosulfonate with at least one organic nitrogen base; and (C) a mixture of an organic nitrogen base and an acid selected from the group consisting of sulfuric acid, sulfurous acid and sulfamic acid, and heat treating the product in an inert atmosphere at a temperature of at least about 400* C. for a period of time sufficient to bring about carbonization.

Inventors

  • 👤 Kazuo Miyamichi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 05:01
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/16; Y; Y02; Y02P; Y02P20/00; Y02P20/10; Y02P20/129

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 16 words
The process of claim 1 in which the strength-increasing agent includes a flame resistance improving agent.
Claim 2
Dependent Claim 33 words
The process of claim 2 in which the flame-resistance-improving agent comprises at least one compound selected from the group consisting of ammonium phosphate, guanidine phosphate, aluminum ammonium sulfate, and tetrakis (hydroxymethyl) phosphonium chloride.
Claim 3
Dependent Claim 19 words
The process of claim 1 in which the strength-increasing agent is applied in the form of an aqueous solution.
Claim 4
Dependent Claim 29 words
The process of claim 1 in which the heat treatment of step (b) is carried out at a heating rate of about 1* to about 5* C. per minute.
Claim 5
Dependent Claim 24 words
The process of claim 1 in which the heat treating is effected at a temperature increasing up to not less than about 1,000* C.

References Cited (Backward Citations)

US3305315A Cited
US3333926A Cited
US3297405A Cited
US3461082A Cited
US3479150A Cited
US3532466A Cited
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US3441378A Cited
US3527564A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-01-31 1975-08-02 1976-02-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-01-31 1979-08-02 1980-02-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-01-31 1983-08-02 1984-02-01 $7700.00 Window Closed / Lapsed

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