US3994850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modified urea-formaldehyde resin adhesive
Assignee: US PLYWOOD Corp A CORP OF
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Filing: 1976-01-05
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Granted: 1976-11-30
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Expires: 1996-01-05
Abstract
Abstract Improved adhesive resin and resin-containing products are described. These adhesives are urea-formaldehyde resins formed in the presence of lignin-sulfonate extender.
Inventors
- 👤 Walter N. Willegger
- 👤 Horst G. Thiel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:13
CPC Classifications
C; C09; C09J; C09J161/00; C09J161/20; C09J161/22; C09J161/24; C08; C08G; C08G12/00; C08G12/02; C08G12/04; C08G12/10; C08G12/12; C09J197/00; C08L; C08L2666/00; C08L2666/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
155 words
A process for producing a modified resin adhesive comprising: a. forming a basic aqueous medium of formaldehyde, urea, and lignin-sulfonate having a pH of from 7.1 to 8.5, said formaldehyde and urea being provided in a mole ratio of from 1.8 to 2.5:1 and said lignin-sulfonate comprising from 5 to 30% by total solids weight and heating said basic aqueous medium to a temperature of from 65° to 95° C; b. acidifying and maintaining said medium at a pH of from 5.0 to 6.5 and at a temperature of from 88° to 98° C for a period of time sufficient to form adhesive resin; c. adjusting the medium containing resin to an alkaline pH of from 7.1 to 7.4 and adding sufficient urea to the basic medium to provide a formaldehyde:urea mole ratio of from 1.2 to 1.7:1; and d. cooling said medium to a temperature below 65° C to produce a stable adhesive resin.
Claim 2
Dependent Claim
155 words
A process for producing a modified resin adhesive comprising: a. forming a basic aqueous medium of formaldehyde, urea, and lignin-sulfonate having a pH of from 7.1 to 8.5, said formaldehyde and urea being provided in a mole ratio of from 1.8 to 2.5:1 and said lignin-sulfonate comprising from 5 to 30% by total solids weight and heating said basic aqueous medium to a temperature of from 65° to 95° C; b. acidifying and maintaining said medium at a pH of from 5.0 to 6.5 and at a temperature of from 88° to 98° C for a period of time sufficient to form adhesive resin; c. adjusting the medium containing resin to an alkaline pH of from 7.1 to 7.4 and adding sufficient urea to the basic medium to provide a formaldehyde:urea mole ratio of from 1.2 to 1.7:1; and d. cooling said medium to a temperature below 65° C to produce a stable adhesive resin.
Claim 3
Dependent Claim
29 words
The process of claim 1, wherein the lignin-sulfonate of the aqueous medium of step (a) is present in an amount of from 5 to 15% by total solids weight.
Claim 4
Dependent Claim
28 words
The process of claim 1, wherein from 0.5 to 5% by solids weight of an ammonium salt of a strong acid is incorporated into the cooled, stabilized resin.
Claim 5
Dependent Claim
10 words
The adhesive resin produced by the process of claim 1.
Claim 6
Dependent Claim
60 words
In a composite board comprising adhesively bound particulate cellulosic material, said board being formed by subjecting an admixture of said material and 4 to 15% of adhesive resin by weight to conditions of pressure and temperature sufficient to cure said admixture into an integral composite structure, the improvement which comprises forming said board with the adhesive resin of claim 4.
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) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |