PURPOSE: To obtain a substantially shear-free, high-quality gel-like polymer continuously and easily in an excellent volume efficiency, by performing polymerization by using a specified straight tubular reactor whose diameter is enlarged just after the gelation zone.
CONSTITUTION: A straight tubular reactor 5 is constructed by enlarging its diameter just after the gelation zone so that the sectional area on the outlet side of the body of a tube having a feed inlet 7 at the lower part and a polymer outlet 8 on the upper part may be larger than the sectional area on the feed inlet side and surrounding the outside of its body with a jacket 9 having an inlet 10 and an outlet 11 for cooling water. A feed material 1 which can give a gel-like polymer such as polyacrylic acid and a catalyst 2 such as a mixture of (NH4)2O2 with NaHSO3 are fed to and mixed in a mixing tank 3 in a N2 atmosphere. The resulting mixture is continuously sent to said reactor 5 by a pump 4, is subjected to polymerization by heating to 60±3°C and is allowed to ascend through the inside of the tube without being sheared because it reaches the area of an enlarged diameter soon after gelation occurs. The gel-like polymer after polymerization is cut with a cutter 12 to a desired size to obtain the purpose polymer continuously from a discharge outlet 13.
MORI HIDETARO
TSUBONE HIROSHI
OMOTO SETSUO
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