Abstract
The tendency of pulp resin particles to coagulate and then adhere to wire and fibrous surfaces causes what is generally known in the paper industry as “pitch trouble”. This is almost specific to the production of pulp and paper from woods by sulfite process or kraft process, but it can occur to an equal degree in mills handling waste papers. An attempt was made to obtain some fundamental knowledge on the reduction of pitch-causing potential through chemical analysis of the pitch samples obtained in boardmaking mills. The result has indicated that the major components of deposited pitch are lignin substances and neutral resin compounds existing in pulp, and resin ous polymers originally located in the waste papers. This would imply that the pitch-causing potential of these waste papers would be no less than that of pulp material. A few methods which would contribute to the control of pitch problems encountered in board manufacture have been suggested on the basis of numerical figures obtained from pitch analysis.
