| 摘要 |
PROBLEM TO BE SOLVED: To concentrate a polymer latex to a high degree of concentration effectively with a vibration type membrane separation apparatus by vibrating its separation membrane at a specific torsional vibration frequency and a specific torsional vibration angle and applying a specific temperature and a specific operation pressure for separation to keep a high permeation flux. SOLUTION: A polymer latex is concentrated with a vibration type membrane separation apparatus using a torsional vibration frequency of 40-80 Hz and a torsional vibration angle of 4-12 degree for membrane vibration at a temperature of 10-50 deg.C and an operation pressure of 2-15 kg/cm2G. A nano filter, a reverse osmosis membrane or the like is used for the separation membrane. If the particle size distribution of the polymer latex has only one frequency local maximum, the concentration is preferably carried out at 30-45 deg. and an operation pressure of 2.3-3.5 kg/cm2G. If the particle size distribution of the polymer latex has two frequency local maximums, the concentration is preferably carried out at 35-45 deg. and an operation pressure of 3.0-4.0 kg/cm2G. The polymer latex is preferably a vinyl chloride polymer latex having a glass transition temperature of not less than 60 deg.C or a methyl methacrylate polymer latex.
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