Atrak Pulp & Paper Industries Ltd.
Sponsored Links
This presentation is the property of its rightful owner.
1 / 27

Paper & Board Coating PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

Atrak Pulp & Paper Industries Ltd. Paper & Board Coating. Why is Paper Coated ??. Cellulose Fiber Size : Soft Wood : Length 3 ~ 4 mm Diameter 25 ~ 50 Micron Hard Wood: Length 0.8 ~ 1.5 mmDiameter 10 ~ 35 Micron Pores between Fibers : 10 ~ 100 Micron.

Download Presentation

Paper & Board Coating

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Atrak Pulp & Paper Industries Ltd.

Paper & Board Coating

Why is Paper Coated ??

  • Cellulose Fiber Size :

  • Soft Wood : Length 3 ~ 4 mm Diameter 25 ~ 50 Micron

  • Hard Wood: Length 0.8 ~ 1.5 mmDiameter 10 ~ 35 Micron

  • Pores between Fibers : 10 ~ 100 Micron.

  • Printing Dot Diameter : 25 ~ 50 Micron.

Coating the paper surface with Fine Pigments (Diameter 1~2 Micron)

to cover the fibers and fill the pores.

Why is Paper Coated ??

  • Printability

  • Smoothness

  • Uniformity

  • Ink Receptivity

  • Visual Properties

  • Brightness

  • Opacity

  • Gloss

  • Functionality

  • Reduce Ink Consumption

  • Glueability

Coatings Purposes

The whole purpose of a coating is to attach uniform layer of pigment to the base sheet.

A Binder is used to adhere the pigment to the fibers.

There are additional additives in the coating formula to help in processing or enhance final sheet properties.

Photo of Un-coated Paper

Magnification 200x

Photo of Coated Paper

Magnification 2000x

Cross Section of Coated Paper

Magnification 2000x

Coating Ingredients

Natural Pigment: Clay, Calcium Carbonate, Talc.

Synthetic Pigment: PCC, Plastic Pigment, TiO2, Silica, Satin White.

Synthetic Binder: Latex.

Hydrosolubles Binder: Starch, CMC, PVA, Casein.

Additives: Dispersant, Thickener, Cross Linker, OBA, Lubricant, De-Foamer, etc.


Coating Ingredients, Dry Weight %

Function of Coating Ingredients

Pigment: Govern optical & printing properties of the paper.

Binders: Give the cohesion of the coating & adhesion of pigments to the base

paper without affecting the properties brought by pigments.

Dispersant: To disperse the pigments.

Cross Linker: Provide wet pick resistant.

OBA: To increase brightness.

Lubricant: Improves flow properties, prevent coating adhesion on to calendar.

Thickener: Modifies the rheology and/or the water retention of the colour.

De-Foamer: Reduces foam.


Interest : paper & ink gloss, rotogravure printability, stiffness.


Draw back : lack of brightness, closed coating.

Interest : brightness, low viscosity, high solid, ink porosity.


Draw back : gloss, low water retention, fiber coverage.

Interest : opacity, brightness, whiteness


Draw back : cost, latex demanding.


Plastic Pigment

Interest : high gloss, brightness, low specific gravity.

Draw back : price, more latex demand.

Interest : brightness, viscosity, low abrasivity.


Draw back : cost, more latex demand.

Interest : brightness, high specific area, opacity.


Draw back : cost, need higher cohesion binder.


Interest : smoothness, non abrasive, best for gravure.


Draw back : gloss.

Satin White

Interest : high gloss.

Draw back : work ability.

Pigment Structure

Magnification 5000x

Pigments Properties

Brightness : 84 ~ 96 % ISO

Particle Size Distribution : 0.22 ~ 2.00 Micron

Surface Area :

Fine Clay20 ~ 25m2/gram

Standard Clay18 ~ 20 m2/gram

Calcined Clay13 ~ 17 m2/gram

GCC 8 ~ 13 m2/gram

Pigments Properties

Refractive Index :

Light Comes

Angle I



Light Refracted

R.I. is amount of lights refracted by the pigments.

Angle R

High R.I. = High Opacity.

Pigments Properties



Hard Latex : Higher gloss, low binding power, mainly for top coat.

Web Offset Latex : Blistering resistance, low binding power.

Soft Latex : Lower cost, high binding power, best for pre coat.


Interest: Stiffness, price.

Draw Back: Mottling, low binding power, rheology at high speed.



Interest: Water retention, rheology, binding power.

Draw Back: Handling.


Interest: Excellent binding power, gloss, brightness.

Draw Back: Price, rheology at high level.


Interest: Water retention, binding power, bulkier coating layer.

Draw Back: Handling, rheology at high level, microbiology control.

What Does Binder Do ?

  • To hold the pigments on the base paper.

  • To help give good printability.

  • To give special characteristic.




Latex Structure

Latex Particles

Pigments Particles

Main Binder Types

  • Styrene Butadiene.

  • Styrene Acrylic.

  • Styrene Butadiene Acrylic.

  • Vinyl Acetate.

The Influence of Binder

  • Dry and Wet Pick Strength.

  • Sheet and Ink Gloss.

  • Printability.

  • Blister Resistance.

  • Ink Drying.

  • Yellowing.

The Influence of Binder

Sheet Gloss

Ink Gloss


Coat Weight


Solid Content

Rheology Modifier (Thickener)

Increase low shear viscosity to allow proper application.

Adjust high shear viscosity to provide coat weight control and run-ability.

Increase water retention.

Can enhance optical and printing properties of the finished sheet.

Rheology Modifiers



Poly - Acrylates  Alco Gum

Sodium Alginate

Urethane Modified Acrylates  Poly Phobe

Cellulosic  Carboxyl Methyl Cellulose (CMC),

Hydroxyl Ethyl Cellulose (HEC)

Atrak Pulp & Paper Industries Ltd.


  • Login