METHOD FOR SHIFTING PRODUCTION GRADE OF POLYMER AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a method for efficiently shifting production grade while minimally reducing occurrence of off-specification products accompanying shifting of grade. SOLUTION: This method for shifting production grade in a production process of polymers has (A) a polymerization step by a continuous polymerization method and (B) a step for uniformly mixing the polymerized polymer. In the method, optimal quality value orbit in the outlet of the step (A) is prepared before shifting the grade under conditions in which the quality value of a product uniformized in the step (B) satisfies production target of each grade before and after shifting of grade and when the shifting of the grade is carried out, operation conditions are controlled by using the quality value orbit as the target.