Study The Effect Of Surface Sizing Technology On Printability Of Bagasse Pulp Offset Paper

The quality of offset paper should be improved to meet with the development of high-speed offset printing techniques. The surface sizing techniques can influence the printability directly. It is very important to choose and confect sizing chemicals properly to improve printability of paper, especially for the paper which contain most bagasse fiber or other non-wood fibers.The effects of different sizing process on the printability of bagasse pulp offset paper were studied in the thesis. The optimal sizing conditions were as follows: sizing temperature was 60℃, total concentration of chemicals was 10%.The effects of different chemicals on printability of paper were analyzed by the properties of sizing degree, Cobb, surface strength, absorbency and air permeability, and the surface microstate and water resisting property of paper were studied by SEM and EST.The experiment results showed that sizing with oxide starch could improve the surface strength, absorbency and interior water resisting property of paper. Compared with oxide starch, phosphate starch which was amphoteric, could increase the surface strength of the paper more, but it could reduce the surface sizing degree of paper for its hygroscopic.When sized with starch and PVA together, the surface strength of the paper could be increased obviously, and be increased along with the rate of PVA. But the air permeability of the paper was reduced, and the absorbency value was increased when PVA sized. The osmotic curve showed PVA could increase the interior water resisting property of paper when it coated.At the same coating dosage 1g/m~2, when the proportion of starch and PAM is 5:1, the surface strength of paper can increase by 22% than the paper sized with proportion of starch and PVA is 5:1, and the former also can reduce the roughness and air permeability of paper.Surface sizing degree and surface strength of the paper could be increased, absorbency and water resisting property of the paper could be improved when coated with SAE.Water-resistant chemicals from Bossco Co. had the same effect on water resisting property and absorbency of the paper when it sized. It could also improve the surface strength of the paper more than PVA and PAM, but less than SAE.At last, good quality offset paper could be obtained in paper mill by adjusting the sizing process and the proportion of chemicals.