Patent US4465586A successfully refreshed from Google Patents.
US4465586A
Expired / Lapsed
US
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Formation of optically anisotropic pitches
Assignee: EIDP Inc
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Filing: 1982-06-14
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Granted: 1984-08-14
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Expires: 2002-06-14
Abstract
Abstract An improved process for preparing liquid crystal containing pitches includes extracting carbonaceous isotropic pitches with an organic solvent system which comprises at least one member of the group consisting of dioxane, dimethylacetamide, and tetramethylurea.
Inventors
- 👤 Russell J. Diefendorf
- 👤 Joe G. Venner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:24
CPC Classifications
C; C10; C10C; C10C3/00; C10C3/08; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/145
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
In a process for producing an optically anisotropic deformable pitch by extracting a carbonaceous isotropic pitch, prior to fiber formation therefrom, with an organic solvent system to form a solvent insoluble fraction which is then separated from the resulting organic solvent system fraction; and heat treating said insoluble fraction the improvement which comprises employing as said organic solvent system at least one member of the group consisting of dioxane, and tetramethylurea.
Claim 2
Dependent Claim
71 words
In a process for producing an optically anisotropic deformable pitch by extracting a carbonaceous isotropic pitch, prior to fiber formation therefrom, with an organic solvent system to form a solvent insoluble fraction which is then separated from the resulting organic solvent system fraction; and heat treating said insoluble fraction the improvement which comprises employing as said organic solvent system at least one member of the group consisting of dioxane, and tetramethylurea.
Claim 3
Dependent Claim
48 words
The process of claim 1 wherein said organic solvent system is used in an amount sufficient to produce a solvent insoluble fraction having a sintering point below about 350° C. when determined by differential thermal analysis of a sample of the insoluble fraction in the absence of oxygen.
Claim 4
Dependent Claim
33 words
The process of claim 2 wherein said organic solvent system is used in an amount sufficient to provide a solvent insoluble fraction having a sintering point in the range of about 300°-340° C.
Claim 5
Dependent Claim
27 words
The process of claim 1 wherein the isotropic pitch is treated with about 5-150 ml of said organic solvent system per gram of pitch at ambient temperature.
Claim 6
Dependent Claim
60 words
The process of claim 1 wherein the solvent insoluble fraction is heated to a temperature of about 230°-400° C. whereby said fraction is converted to a deformable pitch containing greater than 75% of an optically anisotropic phase and which phase when extracted with quinoline at 75° C. contains less than about 25 wt. % of substances insoluble in said quinoline.
Claim 7
Dependent Claim
31 words
The process of claim 5 wherein the heating of said solvent insoluble fraction is effected while extruding the said heated insoluble fraction through an extrusion orifice thereby forming a pitch fiber.
Claim 8
Dependent Claim
42 words
The process of claim 1 wherein said isotropic carbonaceous pitch is heated at a temperature in the range of about 350°-450° C. for a time sufficient to increase the solvent insoluble fraction of the pitch before contact with said organic solvent system.
Claim 9
Dependent Claim
29 words
The process of claim 7 wherein said preheating is terminated just prior to the time when spherules become visible upon polarized light microscopic examination of samples of the pitch.
Claim 10
Dependent Claim
11 words
The process of claim 1 wherein said solvent system comprises dioxane.
Claim 11
Dependent Claim
11 words
The process of claim 1 wherein said solvent system comprises tetramethylurea.
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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) | 1987-08-14 | 1988-02-13 | 1988-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-14 | 1992-02-13 | 1992-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-14 | 1996-02-13 | 1996-08-14 | $7700.00 | Window Closed / Lapsed |