| 摘要 |
Raw material resorcin, an aqueous solution of calcium chloride recovered and recovered MEK are added into a water solvent, and further a hydrochloric acid catalyst is added thereto. Formalin is dropped in the reaction system to thereby advance a liquid-liquid heterogeneous reaction. The water layer (0) is removed, and water is added to the MEK layer (0), followed by satisfactory water washing. The water layer (1) is removed, and the water washing operation is further carried out at least once. The water layer (2) is removed, and water is added to the resultant MEK layer (2) containing MEK-modified resorcin/formalin resin. Further, 1 to 30% aqueous ammonia is added thereto and rectified to thereby realize recovery and reuse of MEK. Methanol is removed from the water layer (0) by vacuum distillation, and the resultant water layer after adjusting of calcium chloride concentration therein is recycled to the reaction system to thereby attain reuse thereof. Thus, there is provided a process for producing an MEK-modified resorcin/formalin resin parallelly carrying out recovery and reuse of specified raw materials (methanol, calcium chloride and MEK), in which finally, there is obtained an aqueous solution of resorcin/formalin resin exhibiting a reaction product concentration of 30 to 80% and a pH value of 6 to 10 to have an appropriate fluidity; and exhibiting a calcium chloride concentration of 100 ppm or below; a ratio of peak area corresponding to resorcin monomer to overall peak area, as obtained by gel permeation chromatography analysis, of 3 to 9%; and a ratio of peak area corresponding to five or more resorcin nuclei to the above overall peak area of 30 to 55%.
|
