| PATENT ASSIGNEE'S COUNTRY | UK |
| UPDATE | 06.99 |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT CLAIMS |
- Condensing formol with phenolic compds in presence of acid catalyst & photoresist solvent - Adding water to mixt. thereby forming 2 soln layers, top la yer comprising soln of unreacted phenols, novolak oligo mer & monomers in water & bottom layer soln of remaining mixt in solvent & removing top layer - Adding water soluble organic polar solvent & water to bo ttom layer thereby again forming 2 soln layers, bottom la yer comprising soln of novolak resin condensation prodt in reaction solvent & top layer comprising soln of novolak oli gomers & monomer in solvent comprising water/water solu ble organic polar solvent/reaction solvent & removing the top layer - Repeating second & third steps 2 - 10 times for bottom la yer - Diluting remaining novolak resin soln with a solvent compri sing reaction solvent & removing any remaining water & wa ter soluble organic polar solvent, & thereby producing a film forming fractionated novolak resin |
| PATENT PHOTOCOPY | Available on request |
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