| 摘要 |
Phenol-aldehyde cation-exchange resins containing reactive silver are prepared from cation-exchange resins obtained by condensing a mono- and/or poly-hydric phenol with an aldehyde by charging with alkali and then treating with a solution of a silver salt. Excess of electrolyte, e.g. silver nitrate, or a protective p colloid may be mixed with the product. In examples: (1) an alkali-condensed resorcinol-formaldehyde resin is washed free of formaldehyde, then treated thrice with hydrochloric acid and caustic soda successively; dried and ground, and treated for 10 minutes with silver nitrate solution; (2) an acid-condensed resorcinol-formaldehyde resin is dried and aged for 2 months, treated with caustic soda, then hydrochloric acid, then caustic soda again and finally for 10 minutes with silver nitrate solution; (3) an alkali-condensed phenol-formaldehyde resin is sulphonated by sulphuric acid, then treated with acid and alkali twice in succession, then for 5 minutes with silver nitrate solution. |
