Study On Use Of Functional Chemicals For Easing Lining And Pull-up Of The Paper

The internal sizing and surface sizing to improve the surface strength of handsheet are discussed respectively in this paper, and the optimal conditions are obtained. During the process of internal sizing and surface sizing, the functional chemicals are applied in the way of the one-component or two-component.The result of internal sizing shows that one-component enhancer increases surface strength of handsheet only to a certain extent, among them chitosan, cationic starch and CMC increases picking speed to3.42m/s,3.10m/s and2.40m/s respectively from0.9m/s without enhancer. While the effect of two-component enhancer is better than that of one-component. This means that the two kinds of combined strengthening agent can more fully play enhancement effect. Based on enhencer dosage, effect on picking speed, and the cost of cationic starch, CMC and chitosan, the optimal conditions are as followed:when picking speed reaches4.00m/s,(1)0.50%CMC and2.50%starch, its cost is1.03yuan/kg pulp,(2)0.81%CMC and0.54%chitosan, its cost is1.05yuan/kg pulp,(3)0.81%starch and0.54%chitosan, its cost is1.09yuan/kg pulp; when3.50m/s of picking speed is enough, the lowest cost of the combination is that (1)1.08%CMC and0.27%chitosan,(2)1.08%starch and0.27%chitosan, the cost is0.73yuan/kg and0.78yuan/kg pulp respectively.The result of surface sizing proves that effect of surface sizing on picking speed is greater than that of internal sizing. Similarly, in surface sizing experiments, the effect of two-component enhancer is better than that of one-component. The selected conditions are that ratio of starch and CMC is4:1, the total amount is1.20g/m2, the cost is0.58yuan/kg pulp, picking speed can reach to4.00m/s; ratio of starch and chitosan is6:1, the sum amount is0.50g/m2, the cost is0.37yuan/kg pulp, picking speed can reach to3.50m/s.Within the internal sizing and surface sizing, the optimal conditions are as followed:when picking speed reaches3.50m/s or so, the best process conditions is1.08%CMC and0.27%chitosan in the internal sizing within, at the same time, the ratio of starch and CMC is4:1in the surface sizing within; when picking speed reaches4.00m/s or so, the best process conditions is2.50%starch and0.27%CMC in the internal sizing within, at the same time, the ratio of starch and CMC is4:1in the surface sizing within.