Phenol formaldehyde adhesive for bonding wood pieces of high moisture content and composite board and veneers bonded with such adhesive
US4824896A · kind A · utility
Inventors
Key dates
| Filing date | Mar 9, 1988 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | Mar 9, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09J161/04
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Disclosed is an improved phenol formaldehyde (PF) resin that does not require fillers or extenders and is capable of bonding wafers or veneers having a moisture content of 10% or above. In the case of veneers exceptional results are obtained when the permeability of the veneer is increased by incising. The adhesive composition is prepared by mixing together a caustic solution of a high molecular weight PF resin, a dispersion of PF resin which is characterized in that it can swell in aqueous caustic medium but not go into solution, and a chemical which is capable of reacting with resins in both the continuous and the disperse phase, such as alkylene carbonates or phenol resorcinol formaldehyde (PRF) resins. Optionally, a component may be used such as borax which is capable of complexing with resins in the continuous and the disperse phase. The disperse phase is made by converting a solution of a PF resin into a fine particle size particulate form by precipitation, spray drying or freeze drying and partially cross-linking the resin during or subsequent to the formation of the fine particle size dispersion. The PF resin is partially cross-linked by (a) heat, by (b) acid catalysis, or …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.