US4075149A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aqueous urea-formaldehyde resin compositions having improved storage life
Assignee: Gulf Research and Development Co
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Filing: 1977-02-24
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Granted: 1978-02-21
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Expires: 1997-02-24
Abstract
Abstract Urea-formaldehyde resin compositions having improved (longer) storage lives are provided by incorporating minor quantities of salts of certain complexed zinc ions into concentrated urea-formaldehyde resin compositions. The complexed zinc salts that can be employed for this purpose include zinc-ammonia carbonate and zinc-ammonia sulfate.
Inventors
- 👤 Pallavoor R. Lakshmanan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:05
CPC Classifications
C; C08; C08L; C08L61/00; C08L61/20; C08L61/22; C08L61/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
151 words
A method for preparing an aqueous solution of a urea-formaldehyde resin having a reduced tendency to polymerize at ambient temperature, which consists essentially of heating one mol of urea with 1.5 - 2.0 mols of formaldehyde in an aqueous medium, adjusting the pH of the resulting resin solution to a value greater than 7.0 by adding ammonium hydroxide to the solutions as the sole alkali, concentrating the resin solution by distillation so that it contains at least 50% by weight of resin solids, and incorporating into the resin solution a minor quantity of a salt of a complexed zinc ion sufficient to retard the rate of polymerization of the urea-formaldehyde resin at ambient temperature, said complexed zinc ion having the structure: ##STR2## where R 1 , R 2 and R 3 are independently selected from the group consisting of hydrogen atoms and lower alkyl groups containing up to 5 carbon atoms.
Claim 2
Independent Claim
151 words
A method for preparing an aqueous solution of a urea-formaldehyde resin having a reduced tendency to polymerize at ambient temperature, which consists essentially of heating one mol of urea with 1.5 - 2.0 mols of formaldehyde in an aqueous medium, adjusting the pH of the resulting resin solution to a value greater than 7.0 by adding ammonium hydroxide to the solutions as the sole alkali, concentrating the resin solution by distillation so that it contains at least 50% by weight of resin solids, and incorporating into the resin solution a minor quantity of a salt of a complexed zinc ion sufficient to retard the rate of polymerization of the urea-formaldehyde resin at ambient temperature, said complexed zinc ion having the structure: ##STR2## where R 1 , R 2 and R 3 are independently selected from the group consisting of hydrogen atoms and lower alkyl groups containing up to 5 carbon atoms.
Claim 3
Dependent Claim
24 words
An aqueous solution of a urea-formaldehyde resin having a reduced tendency to polymerize at ambient temperature and prepared by the method of claim 1.
Claim 4
Dependent Claim
26 words
A resin solution of claim 2 in which the salt of the complexed zinc ion constitutes about 0.1 to 4.0 weight % of the total composition.
Claim 5
Dependent Claim
19 words
A resin solution of claim 3 in which the salt of the complexed zinc ion is zinc ammonia carbonate.
Claim 6
Dependent Claim
19 words
A resin solution of claim 3 in which the salt of the complexed zinc ion is zinc ammonia sulfate.
References Cited (Backward Citations)
US2438244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |