US3884907A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Regenerated cellulose recovery process using a humid gas to remove coating solvent
Assignee: Shawmut Capital Corp
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Filing: 1974-09-05
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Granted: 1975-05-20
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Expires: 1994-09-05
Abstract
Abstract In a regenerated cellulose recovery process wherein (1) coated, softened, regenerated cellulose is comminuted, (2) the softener is removed leaving coated regenerated cellulose having open internal pores, (3) the coating is removed from the regenerated cellulose by flushing with a coating solvent, and (4) the regenerated cellulose is dried of coating solvent, the improvement wherein the regenerated cellulose is dried of coating solvent by contacting the regenerated cellulose having a solvent content of at least about 6% by weight at an elevated temperature with a gas stream containing an effective amount of water vapor to raise the regenerated cellulose water content to about 7 to 22 percent by weight and to reduce the coating solvent content of the regenerated cellulose. In a preferred embodiment, steam is selected as the gas stream and residual coating solvent is reduced to less than about 1 percent by weight.
Inventors
- 👤 Dale Roderic Laurance
- 👤 Richard Dale Roe
- 👤 Robert Gene Sheppard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:18
CPC Classifications
C; C08; C08J; C08J11/00; C08J11/04; C08J11/06; C08J11/08; C08L; C08L1/00; C08L1/02; C08J2301/00; C08J2301/02; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S264/00; Y10S264/911; Y10S264/913; Y10S264/914
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
128 words
IN A REGENERATED CELLULOSE RECOVERY PROCESS WHEREIN (1) COATED, SOFTENED, REGENERATED CELLULOSE IS COMMINUTED, (2) THE SOFTENER IS REMOVED LEAVING COATED REGENERATED CELLULOSE HAVING OPEN INTERNAL PORES, (3) THE COATING IS REMOVED FROM THE REGENERATED CELLULOSE BY FLUSHING WITH A COATING SOLVENT, AND (4) THE REGENERATED CELLULOSE BY FLUSHING WITH A COATING SOLV ENT, IS DRIED OF COATING SOLVENT, THE IMPROVEMENT WHEREIN THE REGENERATED CELLULOSE IS DRIED OF COATING SOLVENT BY CONTACTING THE REGENERATED CELLULOSE HAVING A SOLVENT CONTENT OF AT LEAST ABOUT 6 PERCENT BY WEIGHT AT AN ELEVATED TEMPERATURE WITH A GAS STREAM CONTAINING AN EFFECTIVE AMOUNT OF WATER VAPOR TO RAISE THE REGENERATED CELLULOSE WATER CONTENT TO ABOUT 7 TO 22 PERCENT BY WEIGHT AND TO REDUCE THE COATING SOLVENT CONTENT OF THE REGENERATED CELLULOSE.
Claim 2
Dependent Claim
128 words
IN A REGENERATED CELLULOSE RECOVERY PROCESS WHEREIN (1) COATED, SOFTENED, REGENERATED CELLULOSE IS COMMINUTED, (2) THE SOFTENER IS REMOVED LEAVING COATED REGENERATED CELLULOSE HAVING OPEN INTERNAL PORES, (3) THE COATING IS REMOVED FROM THE REGENERATED CELLULOSE BY FLUSHING WITH A COATING SOLVENT, AND (4) THE REGENERATED CELLULOSE BY FLUSHING WITH A COATING SOLV ENT, IS DRIED OF COATING SOLVENT, THE IMPROVEMENT WHEREIN THE REGENERATED CELLULOSE IS DRIED OF COATING SOLVENT BY CONTACTING THE REGENERATED CELLULOSE HAVING A SOLVENT CONTENT OF AT LEAST ABOUT 6 PERCENT BY WEIGHT AT AN ELEVATED TEMPERATURE WITH A GAS STREAM CONTAINING AN EFFECTIVE AMOUNT OF WATER VAPOR TO RAISE THE REGENERATED CELLULOSE WATER CONTENT TO ABOUT 7 TO 22 PERCENT BY WEIGHT AND TO REDUCE THE COATING SOLVENT CONTENT OF THE REGENERATED CELLULOSE.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein the coating solvent content of the regenerated cellulose is reduced to less than about 1 percent by weight.
Claim 4
Dependent Claim
22 words
The process of claim 2 wherein the regenerated cellulose is heated to about 30* to 100*C. during contact with the gas stream.
Claim 5
Dependent Claim
33 words
The process of claim 3 wherein the gas stream is heated and contains water vapor at a partial pressure within the bounds of lines AB, BC, CD, DE and EA of FIG. 2.
Claim 6
Dependent Claim
11 words
The process of claim 4 wherein the gas stream is nitrogen.
Claim 7
Dependent Claim
19 words
The process of claim 4 wherein external heat is also provided to assist in heating the solvent-ladden regenerated cellulose.
Claim 8
Dependent Claim
10 words
The process of claim 4 wherein the solvent is tetrahydrofuran.
Claim 9
Dependent Claim
11 words
The process of claim 1 wherein the gas stream is steam.
Claim 10
Dependent Claim
19 words
The process of claim 8 wherein external heat is also provided to assist in heating the solvent-laden regenerated cellulose.
Claim 11
Dependent Claim
10 words
The process of claim 8 wherein the solvent is tetrahydrofuran.
Claim 12
Dependent Claim
34 words
The process of claim 1 wherein the solvent content of the regenerated cellulose is reduced to less than about 50 percent prior to contacting the regenerated cellulose with the gas stream containing water vapor.
Claim 13
Dependent Claim
45 words
The process of claim 11 wherein the solvent content of the regenerated cellulose is reduced to less than about 50 percent by distributing the solvent-laden cellulose on a screen and passing a high-velocity stream of a gas through the cellulose to entrain and remove solvent.
Claim 14
Dependent Claim
25 words
The process of claim 11 wherein the regenerated cellulose is heated to about 30* to 100*C. during contact with the gas stream containing water vapor.
Claim 15
Dependent Claim
33 words
The process of claim 13 wherein the gas stream is heated and contains water vapor at a partial pressure within the bounds of lines AB, BC, CD, DE and EA of FIG. 2.
Claim 16
Dependent Claim
11 words
The process of claim 13 wherein the gas stream is steam.
Claim 17
Dependent Claim
22 words
The process of claim 11 wherein liquid water is added to regenerated cellulose having a solvent content less than about 50 percent.
Claim 18
Dependent Claim
115 words
In a regenerated cellulose recovery process wherein (1) coated, softened, regenerated cellulose is comminuted, (2) the softener is removed leaving coated regenerated cellulose having open internal pores, (3) the coating is removed from the regenerated cellulose by flushing with a coating solvent, and (4) the regenerated cellulose is dried of coating solvent, the improvement wherein the regenerated cellulose is dried of coating solvent by contacting the regenerated cellulose having a solvent content of at least 6 percent by weight with steam to raise the regenerated cellulose water content to about 7 to 22 percent by weight and to reduce the coating solvent content of the regenerated cellulose to less than about 1 percent by weight.
Claim 19
Dependent Claim
115 words
In a regenerated cellulose recovery process wherein (1) coated, softened, regenerated cellulose is comminuted, (2) the softener is removed leaving coated regenerated cellulose having open internal pores, (3) the coating is removed from the regenerated cellulose by flushing with a coating solvent, and (4) the regenerated cellulose is dried of coating solvent, the improvement wherein the regenerated cellulose is dried of coating solvent by contacting the regenerated cellulose having a solvent content of at least 6 percent by weight with steam to raise the regenerated cellulose water content to about 7 to 22 percent by weight and to reduce the coating solvent content of the regenerated cellulose to less than about 1 percent by weight.
Claim 20
Dependent Claim
33 words
The process of claim 17 wherein the solvent content of the regenerated cellulose is reduced to less than about 50 percent prior to contacting the regenerated cellulose with the gas stream containing water.
Claim 21
Dependent Claim
23 words
The process of claim 18 wherein liquid water is added to the regenerated cellulose prior to contacting the regenerated cellulose with the steam.
Claim 22
Dependent Claim
24 words
The process of claim 19 wherein external heat is also provided to assist in heating the solvent-laden regenerated cellulose during contact with the steam.
Claim 23
Dependent Claim
10 words
The process of claim 20 wherein the solvent is tetrahydrofuran.
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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |