ON THE PITCH TROUBLES AT PAPER MILLS AND PRESENT CONDITIONS OF CURING METHODS

Abstract

After having given the causes and aspects of pitch trouble in various spots at Takasago mill of the Mitsubishi Seishi Co. the writer remarks that the extent of trouble may depend upon the kinds of pulp and paper made from, and suggests such curable methods as seen below : 1.Adding 24% of bleaching powder in beater and after treating for 2 hours, to make paper without washing.2.To blend both clay and size in beater after light beating.On judging from the results of his testing, he says that the chief cause of pitch troubles will lie rather in quality, but not in quantity, and it is judged by the degree of stickiness of pitches in pulp, for which test its tackiness ought to be measured.He suggests the following temporary methods as being effective for mill practices : 1.For the separation or isolated pitches washing out; dispersing and washing ;saponification ; salting out in beater ; Having on dandy roll sticked, etc.2.Hardening of soft pitches.3.Setting pitches on fiber.4.Co-operation with pulp makers.