Phenol-resorcinol-formaldehyde resin
US4373062A · kind A · utility
Inventor
Key dates
| Filing date | Apr 20, 1981 |
| Grant date | Feb 8, 1983 |
| Priority date | — |
| Expiry date | Apr 20, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G8/24
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Phenol-formaldehyde and phenol-resorcinol-formaldehyde resinous aqueous syrups useful as thermosetting binders or adhesives are prepared by reacting, a phenol-formaldehyde resin composition firstly at atmospheric reflux temperature at a substantially neutral pH of 5.8 to 8.5 and a formaldehyde to phenol mol ratio between 1.7 to 2.8 for a period of 20 to 120 minutes; reacting secondly with added formaldehyde, if necessary, and also needed alkali metal hydroxide to produce mol ratios of 2.1 to 2.8 and 0.10 to 0.38, respectively, per mol of phenol, for a period of at least two minutes at reflux to produce a liquid phenol-formaldehyde thermosetting resin. The setting time can be decreased, if desired, by using two portions of syrup, reacting one portion for a greater time-temperature period than the other and combining the two portions. By scavenging the remaining free formaldehyde by addition of a suitable reactant and then adding resorcinol and proceeding with a time-temperature period of copolymerization until the desired viscosity, water dilution tolerance, and potential setting speed upon formaldehyde addition are attained, a phenol-resorcinol-formaldehyde resin is obtained. The l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.