| 摘要 |
A process is provided for the production of chemimechanical pulp in the absence of silicate stabilizers. This chemimechanical pulp is characterized by (1) a pulp yield of at least 80% based on dry chips, (2) strength properties as shown by a combination of tear, burst and tensile properties which are superior to refiner mechanical pulp, and, (3) bleaching properties as shown by brightness properties which are superior to both refiner mechanical pulp and cold soda pulp. The chemimechanical pulp is prepared by impregnating hardwood chips with an alkaline peroxide liquor. The alkaline peroxide liquor is an aqueous solution containing about 0.5% to about 4% hydrogen peroxide and about 2.5% to about 10% sodium hydroxide based on dry chips. The impregnated chips have a pH greater than 7.5. The thus impregnated wood chips are then held for about 3 minutes to about 3 hours to soften and bleach the chips after which the chips are acidified to a pH of 7.5 or below by the addition of an acid material and thereafter defibrated by passing the acidified chips through refining apparatus operated at atmospheric pressure. The pulp produced by this defibration is recovered from the refining apparatus. |
