Patent ID: 7297229
Filing Date: 2007-11-20
Classification: D21H,Y10T

Abstract:
1. A process for producing a paper having a bulk density of more than 0.308 g/cm 3 , said process consisting of: obtaining a pulp slurry containing a virgin and/or a deiniced pulp that has been subjected to a deinicing process including both a floatation step and a washing step; adding a cationic compound and a nonionic surfactant to the pulp slurry containing the virgin and/or the deiniced pulp and evenly blending the cationic compound and the nonionic surfactant with the pulp slurry containing the virgin and/or the deinked pulp; and obtaining a paper having a bulk density of more than 0.308 g/cm wherein the cationic compound is a cationic compound represented by formula (a wherein in formula (a the nonionic surfactant is at least one of the nonionic surfactants represented by (A) to (C): (A): a compound represented by the following formula (A) wherein R 81 is a C6 to C22 straight or branched alkyl or alkenyl group or an alkylaryl group having a C4 to C20 alkyl group; E is an ethylene unit; P is a propylene unit; m 81 and n 81 are an average number of added moles, m 81 is a number in the range of 0 to 20 and n 18 is a number in the range of 0 to 50; and the addition form of EO and PO may be any of block and random and the addition order of BO and PO may not be limited; (B): a compound represented by the following formula (B) wherein R 81 , E, P, m 81 and n 81 are the same as those of the formula (A); and R b is H, an alkyl group, an alkenyl group or an alkylaryl group; and (C): a nonionic surfactant selected from the following (1) to (3): (1) a nonionic surfactant based on fat, (2) a nonionic surfactant based on sugar alcohol, and (3) a nonionic surfactant based on sugar, wherein the cationic compound and the nonionic surfactant are added in a combined amount of 0.01 to 10 wt % based on the weight of the virgin and/or the deinked pulp, and wherein a ratio by weight of said cationic compound to the at least one non-ionic surfactant represented by (A) to (C) is from 1/99 to 50/50.