| 摘要 |
A cation-active resin is prepared by reacting phenol, formaldehyde, and a salt of sulphurous acid with a strong base in the presence of water constituting not more than 40 per cent by weight of the initial reaction mixture and curing the reaction product by heating at between 125 DEG and 175 DEG C. Examples describe the reaction of mixtures of phenol, anhydrous sodium sulphite, anhydrous sodium bisulphite (1), (2) and (3) with water and paraformaldehyde; (4), (5) and (6) with formalin. The products are cured first at 100 DEG C., and then at 150 DEG C., except in (6) which is heated to 125 DEG C. The water-softening capacities are composed with those of resins prepared in experiments employing more than 40 per cent of water and/or temperatures of 100 DEG C. Salts of sulphurous acid specified are potassium sulphite, sodium meta-bisulphite, sodium or potassium bisulphite, trimethylamine sulphite, and benzyl trimethyl ammonium bisulphite. Before gelation the product may be applied to a carrier such as diatomaceous earth, clay, or charcoal. |
