Paper\board Sizing process

WHAT purposes surface sizing of paper / board, kecuali?

• –To increase paper / board strength and stiffness

• To increase water absorption

• –To prevent dusting of paper

• –To prevent absorption of ink

Why is technology the film sizing more popular, kecuali?

• Off machine sizing process

• –Excellent runnability and machine efficiency

• –Size amount can be controlled each side independently

• –Wide range of processes from normal surface sizing with starch to special chemicals

What are Raw materials Paper/board surface sized parameters, kecuali?

• –Raw material from potato, rice, corn, tapioca, etc.

• Clay

• –Dry solids content usually 5-12 %

• –To increase opacity some coating pigment can be added to starch sizing

Sizing results had strong Influencing factors, kecuali?

• Pressure

• –Surface sizing method; pond vs. film

• –Size amount

• –Base paper properties

Surface Sizing Positive Effects on paper\board properties, kecuali?

• better strength properties surface strength

     internal bond strength

    tensile strength

• better linting properties , better stiffness

• lower opacity and brightness

• lower porosity

The film sizing process is metered to the rolls which transfer the film in the nip onto the sheet, kecuali?

• 1.Premetering of wet film on the roll surface

• 1.Transfer of premetered wet film on to the paper

• 1.Film-split of non-immobilized film layer

• 1. 1. Non Levelling of non-immobilized film layer

Surface sizing Volumetric metering, ŸWet surface size film amount on the applicator roll depends on, kecuali?

• –Grooved applicator rod type

  ŸGroove profile

  Ÿ(Diameter)

• –Roll cover

  ŸMaterial

  ŸHardness

• –Rod load, Size properties

  ŸSolids content

  ŸViscosity

  ŸRunning speed

• ,Rod rotation speed

Sizing process, Starch distribution in paper\board, kecuali?

• ŸStarch seen as  dark yellow

• ŸStarch seen as  dark blue

• ŸStarch concentrated on the surface of paper\board

• ŸPenetration through the sheet only through the bigger pores of paper\board

Starch transfer and film splitting in roll nip process, kecuali?

• ŸStarch/water penetrated into base paper

• ŸWater removed from size, Immobilizing of size

• ŸWater di not removed from size

• ŸFilm splitting of  non-immobilized wet film layer

  ŸLevelling of wet film layer

Film surface sizing runnability issues, kecuali?

• ŸWater removed from size

• ŸStarch spits at the rod

• ŸUncontrollable web release from the roll

• Ÿ“Web stealing” of the paper web at the nip outlet