Patent ID: 6090533
Filing Date: 2000-07-18
Classification: C08G,G03F

Abstract:
A method for producing a water insoluble, aqueous alkali soluble novolak resin consisting essentially of:a) condensing formaldehyde with one or more phenolic compounds, in the presence of an acid catalyst and, after the condensation reaction is complete, adding a water soluble solvent;b) precipitating the condensation product from step a) by adding water, and removing the unreacted phenolic compounds and oligomers in a water soluble solvent/water solution, and thereby removing the unreacted phenolic compounds and oligomers with said solution;c) dissolving the precipitate from step b) in a novolak resin solvent selected from the group consisting of propylene glycol methyl ether acetate, 2-heptanone, ethyl lactate, ethyl-3-ethoxypropionate, butyl acetate, xylene, diglyme, and ethylene glycol monoethyl ether acetate, and removing the residual water, thereby producing a water insoluble, aqueous alkali soluble, film forming novolak resin.