US4028367A
Expired / Lapsed
US
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High efficiency stable aqueous resoles
Assignee: Monsanto Co
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Filing: 1975-03-10
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Granted: 1977-06-07
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Expires: 1995-03-10
Abstract
Abstract High efficiency stable aqueous resoles which contain low concentration of free phenol and free formaldehyde and cause substantially less pollution of the atmosphere than prior art resins. The resoles are prepared by a two-stage reaction which controls the molecular weight, water tolerance and the ratio of methylolated 2,2'-, 2,4'- and 4,4'-dihydroxydiphenylmethanes. Stability is promoted by inhibition of the crystallization of bis(4-hydroxy-3,5-dimethylolphenyl)methane.
Inventors
- 👤 Harold P. Higginbottom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:08
CPC Classifications
C; C08; C08G; C08G8/00; C08G8/04; C08G8/08; C08G8/10
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
166 words
An aqueous solution of a resole wherein the solution has a pH in the range 6 to 8.5 and contains less than 2 percent of free phenol and less than 2 percent of free formaldehyde based on the weight of the resole and wherein the resole has a number average molecular weight of less than 300, a water tolerance between about 100 and 800 and a combined formaldehyde to phenol molar ratio in the range of 2.0:1 to 2.9:1 and contains sufficient methylolated 2,2'- and 2,4'-dihydroxydiphenylmethanes to inhibit crystal formation in the resole solution said resole being the product of: a. reacting 1.0 mole phenol with from 0.05 to 0.03 moles formaldehyde under conditions for formation of novolac resin, b. adding from 1.75 to 3.5 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 300, and containing less than 2 weight percent free phenol, and c. adjusting the pH of the aqueous resole to between about 6 and 8.5.
Claim 2
Dependent Claim
166 words
An aqueous solution of a resole wherein the solution has a pH in the range 6 to 8.5 and contains less than 2 percent of free phenol and less than 2 percent of free formaldehyde based on the weight of the resole and wherein the resole has a number average molecular weight of less than 300, a water tolerance between about 100 and 800 and a combined formaldehyde to phenol molar ratio in the range of 2.0:1 to 2.9:1 and contains sufficient methylolated 2,2'- and 2,4'-dihydroxydiphenylmethanes to inhibit crystal formation in the resole solution said resole being the product of: a. reacting 1.0 mole phenol with from 0.05 to 0.03 moles formaldehyde under conditions for formation of novolac resin, b. adding from 1.75 to 3.5 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 300, and containing less than 2 weight percent free phenol, and c. adjusting the pH of the aqueous resole to between about 6 and 8.5.
Claim 3
Dependent Claim
46 words
The aqueous solution of claim 1 wherein the resole has a number average molecular weight in the range of 180 to 300 and comprises between 5 and 90 weight percent of methylolated dihydroxydiphenylmethanes of which between 5 and 50 weight percent are methylolated 2,2'- and 2,4'-dihydroxydiphenylmethanes.
Claim 4
Dependent Claim
25 words
The aqueous solution of claim 1 wherein the resole comprises less than 1 weight percent free phenol and less than 1 weight percent free formaldehyde.
Claim 5
Dependent Claim
28 words
The aqueous solution of claim 1 wherein reduction of formaldehyde to less than 2 percent based on the weight of the resole is achieved with a formaldehyde scavenger.
Claim 6
Dependent Claim
57 words
The aqueous solution of claim 4 wherein the scavenger is a soluble nitrogen organic compound of molecular weight less than 300, containing at least one N-H group per molecule which is reactive with formaldehyde said scavenger being selected from the group consisting of ammonia, primary and secondary amines, urea, substituted ureas, primary amides, dicyandiamide, guanidines and aminotriazines.
Claim 7
Dependent Claim
152 words
A process for preparing an aqueous resole solution which comprises: a. reacting 1.0 mole phenol with from 0.05 to 0.30 moles formaldehyde under conditions for formation of novolac resin, b. adding from 1.75 to 3.5 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 300, and containing less than 2 weight percent free phenol, and c. adjusting the pH of the aqueous resole to between about 6 and 8.5, wherein said solution contains less than 2% of free phenol and less than 2% of free formaldehyde based on the weight of the resole and wherein the resole has a number average molecular weight of less than 300, a water tolerance between about 100 and 800 and a combined formaldehyde to phenol molar ratio in the range of 2.0:1 to 2.9:1 and contains sufficient methylolated 2,2'- and 2,4'-dihydroxydiphenylmethanes to inhibit crystal formation in the resole solution.
Claim 8
Dependent Claim
152 words
A process for preparing an aqueous resole solution which comprises: a. reacting 1.0 mole phenol with from 0.05 to 0.30 moles formaldehyde under conditions for formation of novolac resin, b. adding from 1.75 to 3.5 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 300, and containing less than 2 weight percent free phenol, and c. adjusting the pH of the aqueous resole to between about 6 and 8.5, wherein said solution contains less than 2% of free phenol and less than 2% of free formaldehyde based on the weight of the resole and wherein the resole has a number average molecular weight of less than 300, a water tolerance between about 100 and 800 and a combined formaldehyde to phenol molar ratio in the range of 2.0:1 to 2.9:1 and contains sufficient methylolated 2,2'- and 2,4'-dihydroxydiphenylmethanes to inhibit crystal formation in the resole solution.
Claim 9
Dependent Claim
16 words
The process of claim 6 wherein the pH is adjusted to between about 7 and 8.
Claim 10
Dependent Claim
53 words
The process of claim 6 wherein the novolac reaction stage is carried out in the presence of 0.001 to 0.02 mole equivalents of a soluble acid catalyst per mole of phenol at a temperature in the range of 60° to 200° C. and wherein the acid has a pK of less than 5.
Claim 11
Dependent Claim
28 words
The process of claim 8 wherein the catalyst has a pK of less than 2 and wherein the temperature is in the range of 100° to 120° C.
Claim 12
Dependent Claim
69 words
The process of claim 6 wherein the resole reaction stage is carried out in the presence of a soluble basic catalyst of pK greater than about 9.0 at a temperature in the range of 40° to 80° C., the concentration of base being between about 0.05 to 0.3 mole equivalent per mole of phenol in excess of the amount required to neutralize the acid of the novolac reaction stage.
Claim 13
Dependent Claim
33 words
The process of claim 10 wherein the base is selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkaline earth hydroxides, ammonia and amines of molecular weight less than 300.
Claim 14
Dependent Claim
24 words
The process of claim 6 wherein the resole reaction stage is carried out at a temperature in the range of 50° to 70° C.
Claim 15
Dependent Claim
73 words
The process of claim 6 wherein a soluble nitrogen containing organic compound of molecular weight less than 300 containing at least one N--H group reactive with formaldehyde is added as a formaldehyde scavenger to the resole after the free phenol content has dropped to less than 2 weight percent of the resole and is reacted with the free formaldehyde to reduce the formaldehyde concentration to less than 2 weight percent of the resole.
Claim 16
Dependent Claim
48 words
The process of claim 13 wherein the formaldehyde scavenging reaction is carried out at a temperature in the range of 20° to 60° C. and the scavenger is selected from the group consisting of ammonia, primary and secondary amines, urea, substituted ureas, primary amides, dicyandiamide, guanidines and aminotriazines.
References Cited (Backward Citations)
US2593926A
Cited
US3206412A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |