Coating Station

Coated paper or gloss paper is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including kaolinite, calcium carbonate, bentonite, and talc, can be used to coat paper for high-quality printing used in the packaging industry and in magazines.

The chalk or china clay is bound to the paper with synthetic as well as natural organic binders. The coating formulation may also contain chemical additives as dispersants, resins, etc give water resistance and wet strength to the paper.

Online Coating

Coated Duplex Board: This board is used mainly for Packaging Industry used on top side of corrugated Boxes. There are two types of coting for such board. Light weight coating used for normal printing and High weight Coating where packaging is done for high end products. For mono carton, Duplex board with white back is used where coating is done on both sides. These coating is done on paper machine on “On Line Basis”

Types of Coating Machine

All the coating machines (except curtain coater) are having applicator roll which is dipped in a Colour pan and film of coating chemical slurry having solid contents ranging from 50% to 65% in transferred on the paper sheet. To scrap out excess chemical to maintain uniform coating thickness, various devices are used as follows

• Air Knife: Air knife is a non-contact type of scrapper which remove the excess chemical and gives uniform coating on paper but unable to fill hills and valleys of Paper. Mainly used for Low GSM Base Paper.
• Blade- Bar Coater: Scrapping done by Blade is best as it maintains a perfect clearance between paper and blade hence all hills and valleys are filled with chemical hence you get the best gloss on Paper. This unit is most preferred
• Curtain Coater: Coating chemical film falls on running Paper and full chemical is utilized. Highly sophisticated and used for high speed operation. With one unit three different chemicals can be applied. Coating thickness is uniform but there is no evening effect if paper is uneven. Used for lower GSM well calendared Paper.