US4338091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for lowering the viscosity of sulfonated lignins
Assignee: Westvaco Corp
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Filing: 1981-08-13
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Granted: 1982-07-06
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Expires: 2001-08-13
Abstract
Abstract Disclosed herein is a process for preparing sulfonated lignins processing a low viscosity which comprises pretreating a lignin with sodium dithionate and subsequently reacting the pretreated lignin with sodium sulfite and an aldehyde. The resulting sulfonated lignins are useful as dispersants for disperse dyes and vat dyes.
Inventors
- 👤 Peter Dilling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:40
CPC Classifications
C; C08; C08H; C08H6/00; C09; C09B; C09B67/00; C09B67/0071; C09B67/0084; C09B67/0085; C09B67/0086; D; D06; D06P; D06P1/00; D06P1/44; D06P1/46; D06P1/48; D06P1/50
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
66 words
A process for preparing sulfonated lignins possessing low viscosity which comprises the steps of: (a) treating an aqueous lignin solution obtained from an alkaline wood pulping process with from about 1 percent to about 10 percent of sodium dithionate, based on the weight of lignin; and (b) subsequently reacting the sodium dithionite treated lignin with a water soluble sulfite (or bisulfite) in combination with an aldehyde.
Claim 2
Dependent Claim
66 words
A process for preparing sulfonated lignins possessing low viscosity which comprises the steps of: (a) treating an aqueous lignin solution obtained from an alkaline wood pulping process with from about 1 percent to about 10 percent of sodium dithionate, based on the weight of lignin; and (b) subsequently reacting the sodium dithionite treated lignin with a water soluble sulfite (or bisulfite) in combination with an aldehyde.
Claim 3
Dependent Claim
22 words
The process according to claim 1 wherein the amount of sodium dithionite is about 5 percent, based on the weight of lignin.
Claim 4
Dependent Claim
25 words
The process according to claim 1, wherein the lignin solution is adjusted to a pH of about 10 prior to the treatment with sodium dithionate.
Claim 5
Dependent Claim
28 words
The process according to claim 1, wherein the sodium dithionate is added to the lignin solution at a temperature ranging from about 25° C. to about 70° C.
Claim 6
Dependent Claim
14 words
The process according to claim 1, wherein the water soluble sulfite is sodium sulfite.
Claim 7
Dependent Claim
11 words
The process according to claim 1, wherein the aldehyde is formaldehyde.
Claim 8
Dependent Claim
23 words
The process according to claim 1, wherein the mole ratio of water soluble sulfite to aldehyde ranges from about 1.1:0.6 to about 1.5:1.0.
Claim 9
Dependent Claim
19 words
The process according to claim 1, wherein the mole ratio of water soluble sulfite to aldehyde is about 1.3:0.8.
Claim 10
Dependent Claim
30 words
The process according to claim 1, wherein the sodium dithionite treated lignin is reacted with the water soluble sulfite and the aldehyde about 60 minutes after treatment with sodium dithionite.
Claim 11
Dependent Claim
36 words
A dyestuff composition comprising a disperse or vat dye cake and up to 75 percent, by weight of said dyestuff composition, of a dispersant comprised of a sulfonated lignin produced by the process of claim 1.
References Cited (Backward Citations)
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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) | 1985-07-05 | 1986-01-04 | 1986-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-05 | 1990-01-04 | 1990-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-05 | 1994-01-04 | 1994-07-06 | $7700.00 | Window Closed / Lapsed |