Role of Unisol in Technology of Paper Making:

The basic material of paper is cellulose which occur in the form of fibers in many vegetable tissues. The pulp fibers in aqueous suspension subjected to mechanical treatment like beating and refining . Refining is splitting and cutting of the fibers whereas beating is fibrillation and hydration of the fibers., Beating increases bursting strength, tensile strength , folding endurance, smoothness and hardness but decreases tearing resistance, opacity dimensional stability and bulk of paper. At the beater stage materials are added known as " wet End additives " Like mineral fillers ( China Clay, Calcium Carbonate, Titanium Dioxide ) sizing agents ( Rosin or synthetic agents ) Binders ,Resins, Slimicides, Antifoaming agents and dyestuffs.

Unisol has an important place in the beater additives which increases the strength of the sheet. After mechanical treatment the stock is diluted and cleaned, treated with alum and enters the head box where main part of the water is removed by filtration.

The Wet sheet passes through series of presses and then on to the steam heated dryers drums. The dryer section contains size press used for improving the surface properties like writing, erasing and strength quality of the sheet. Unisol is the most important surface sizing agent. In the size press the dilute starch solution is applied to the surface of the paper where it cements the fibers to the body of the paper increasing the surface strength.
After drying the paper role passes on the calendar stack to improve the smoothness and finish of the paper. The third important application of Unisol in the paper industry is in coating where it is used as a binding agent in a pigment layer applied to the paper which improves the printability and finish of the paper.

In Nut shell :
Unisol plays vital role in paper making as " wet end additive " for increasing the strength of the sheet. In surface sizing improving bursting, folding endurance and tensile strength supplementing the beating operations . As a Coating Agent " for binding the pigment layer applied on the paper for improving the printability.