METHOD FOR REMOVING INK/FOREIGN MATERIAL IN PRODUCTION OF WASTE PAPER PULP, METHOD FOR PRODUCING WASTE PAPER PULP AND PRINTING PAPER

摘要

PPROBLEM TO BE SOLVED: To improve ability of removing an alkali-meltable foreign material such as a hot-melt adhesive and enhance qualities of waste pulp and regenerated paper. PSOLUTION: The method for producing the waste pulp comprises carrying out, in order, a disintegration step 1 for disintegrating unsorted waste paper to obtain a fiber suspension, a coarse selection step 4 for removing the foreign material by screening from the suspension obtained by the disintegration step 1, a pre-floatation step 5 for removing ink/the foreign material by floatation from the suspension passed through the coarse selection step 4, a disperse treating step 9 for dispersing the ink/the foreign material from the suspension passed through the pre-floatation step 5 by mechanical stirring, a bleaching step 10 for adding a bleaching chemical to the suspension passed through the disperse treating step 9 and a post floatation step 11 for removing the ink/the foreign material by floatation from the suspension passed through the bleaching step 10. The waste paper pulp is obtained without carrying out alkali soaking. PCOPYRIGHT: (C)2004,JPO