| 摘要 |
PROBLEM TO BE SOLVED: To prepare the subject cationic ion exchanger which is useful for treatment of drinking water with a largely reduced bleeding level of impurities by sulfonating unfuctional polymer at an elevated temperature and/or sulfonation in the absence of oxygen. SOLUTION: The crosslinked styrene polymer is sulfonated at 125-150 deg.C and/or in the absence of oxygen to prepare the polymer preferably having the conductivity profile of <=50μS/cm. For example, before sulfonation, the granular polymer is swollen with a swelling agent such as dichloromethane and then sulfonated with a sulfonating agent selected form chlorosulfonic acid, sulfuric acid, sulfur trioxide, and fuming sulfuric acid in a nitrogen atmosphere. |
