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US4221708A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for polymerization of lignin

Assignee: Westvaco Corp
•
Filing: 1978-08-14
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Granted: 1980-09-09
•
Expires: 1998-08-14
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Abstract

Abstract Disclosed herein is a process for polymerizing technical lignins, hardwood as well as softwood and sulfonated as well as unsulfonated. The process involves the sequential treatment of the lignin material with formaldehyde and air (or oxygen) to increase the molecular weight. The lignin is first treated with from 0.5 to 3.5 moles of formaldehyde per 1,000 grams of lignin at a pH between 10.5 and 11.5 and a temperature from 50 DEG C. to 80 DEG C. for from 3 to 24 hours to form a lignin-formaldehyde adduct, preferably with minimum cross-linking of the lignin. Then, the thus formed lignin-formaldehyde adduct is oxidized at a temperature of from 25 DEG C. to 80 DEG C. with air or molecular oxygen for from 2 to 24 hours.

Inventors

  • 👤 Stephen Y. Lin

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-10 02:34
CPC Classifications
C; C08; C08H; C08H6/00

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 77 words
A two-step method for polymerizing technical lignin comprising; (a) treating the lignin with from 0.5 to 3.5 moles of formaldehyde per 1,000 grams of lignin at a pH of from 10.5 to 11.5, and a temperature from 50° C. to 80° C. for 3 to 24 hours to form a lignin-formaldehyde adduct, and (b) oxidizing the lignin-formaldehyde adduct at a temperature from 25° C. to 80° C. with air or molecular oxygen for 2 to 24 hours.
Claim 2
Dependent Claim 77 words
A two-step method for polymerizing technical lignin comprising; (a) treating the lignin with from 0.5 to 3.5 moles of formaldehyde per 1,000 grams of lignin at a pH of from 10.5 to 11.5, and a temperature from 50° C. to 80° C. for 3 to 24 hours to form a lignin-formaldehyde adduct, and (b) oxidizing the lignin-formaldehyde adduct at a temperature from 25° C. to 80° C. with air or molecular oxygen for 2 to 24 hours.
Claim 3
Dependent Claim 13 words
The method of claim 1 wherein the technical lignin is a sulfonated lignin.
Claim 4
Dependent Claim 13 words
The method of claim 1 wherein the technical lignin is an alkali lignin.
Claim 5
Dependent Claim 14 words
The method of claim 3 wherein the alkali lignin is a hardwood kraft lignin.
Claim 6
Dependent Claim 14 words
The method of claim 3 wherein the alkali lignin is a softwood kraft lignin.
Claim 7
Dependent Claim 17 words
The method of claim 1 wherein the lignin treated with formaldehyde in step (a) is not cross-linked.
Claim 8
Dependent Claim 25 words
The method of claim 1 or 6 wherein the formaldehyde is employed in the amount of 1.5 to 2.5 moles per 1,000 grams of lignin.
Claim 9
Dependent Claim 17 words
The method of claim 1 or 6 wherein the temperature is from 60° C. to 70° C.
Claim 10
Dependent Claim 21 words
The method of claim 1 or 6 wherein the treatment with formaldehyde of step (a) is for 3 to 10 hours.

References Cited (Backward Citations)

US3167523A Cited
US3784493A Cited
US3864276A Cited
US3886101A Cited
US4069217A Cited
US4045421A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-09-09 1984-03-10 1984-09-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-09-09 1988-03-10 1988-09-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-09-09 1992-03-10 1992-09-09 $7700.00 Window Closed / Lapsed

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