| 摘要 |
PURPOSE:To prevent discoloration of impregnated paper to be used for filter during setting or after storage for days by impregnating the paper with a resin formed by a reaction of bisphenol A with an aldehyde in the presence of a basic catalyst. CONSTITUTION:An impregnating liquid is prepd. by dissolving a resin synthesized by a reaction of bisphenol A with an aldehyde in the presence of a basic catalyst in an appropriate solvent. After dipping paper such as nonwoven cloth, machine-made paper, to be used for a material of filter in the impregnating liquid for several sec - several min, the impregnated paper is dried and cured to obtain thus impregnated paper for filter. Suitable basic catalyst is alkali metal chloride, primary - tertiary amine, etc., and suitable solvent for the impregnating liquid is a lower alcohol such as methanol and ethanol. Suitable amt. of the resin to be deposited to the paper is 10-40 pts.wt. expressed in terms of solid of the resin per 100 pts.wt. of the paper. |
