Size Press is one of the major part of the Paper Making machine.It generally consists of two rolls of specific diameter.
The main purpose of Size Press is to apply a solution of starch or other material onto the surface of the dry paper coming from the dryers and then it is again dried.
Some Paper machines contain a unit for the application of certain liquid media to the Web surface like :- Size Press , Top Coater , Bottom Coater , Pre Top Coater.
The Process of applying Starch solution , a Sizing agent Or a mixture of both by means of Size Press is known as Sizing.
The main reason for paper sizing is to increase the strength and printability of paper products by the chemicals ( mostly starch ) applied acting as binding agent.
Starch is the most agent used , but in recent years a combination of Cationic Starch and synthetic copolymers has been increasingly used to improve the effects of surface sizing.
Cationic starch increases strength of the the paper because it binds to the anionic paper fibres.
In Size Press coating Or a thin film of chemicals is applied on the paper web by means of rolls.