Abstract: A dope (36) containing TAC and plasticizer is produced. Foreign materials in the dope (36) are filtrated by a filtration device (57). In the filtration device (57), the dope (36) flows from an outer passage (58a) to an inner passage (58b) through a filter (59). The filter (59) has a first layer (59a), a second layer (59b), and a third layer (59c), which are formed of sintered metal fibers. An average diameter of the sintered metal fibers of the first layer (59a) is 8 mm, that of the second layer (59b) is 4 mm, and that of the third layer (59c) is 20 mm. The filter (59) is roasted 2 hours at 400° C. and reused. Breakages from the sintered metal fibers in the first and second layers (59a, 59b) are filtrated in the third layer (59c).

Abstract: A process for producing microcapsules that have a sufficiently broad particle size distribution to be suitable for use in a pressure measuring films, which process is improved in that it eliminates the need to perform blending and filtering operations while reducing the possible loss in capsule solutions or films or operating efficiency of the capsule applicator. A disperse phase is poured into a disperse medium as the latter is stirred in a preliminary emulsification tank, thereby forming a primary emulsion. The primary emulsion is forced into cylindrical continuous emulsification equipment by means of a metering pump. An emulsion having a broad particle size distribution is produced by lowering stepwise the rotational speed of the inner cylinder of the continuous emulsification equipment in accordance with the following schedule: 3 min and 15 sec at 2900 rpm, 4 min and 15 sec at 2700 rpm, 4 min and 15 sec at 2300 rpm, and 3 min and 15 sec at 2100 rpm.