Dryer section of paper machine

The Size Press Section is a critical part of the paper machine, positioned between the drying and calendar sections. It applies a starch or chemical solution (called "size") to the paper surface to improve its strength, printability, and resistance to water, ink, or oil.

• Function:
  • Applies surface sizing to both sides of the paper
  • Enhances paper surface strength and stiffness
  • Improves ink holdout and printability
  • Controls water and grease absorbency (especially for packaging papers)

• Main Components:
  • Applicator Rolls (Size Press Rolls): Press the sizing solution into the sheet
  • Squeeze Rolls: Ensure uniform application and remove excess liquid
  • Starch/Size Supply System: Delivers controlled amounts of solution
  • Reel or Transfer Felt System: Guides the paper through the nip
  • Drying Cylinders: Re-dry the paper after sizing

• Types of Size Press:
  • Horizontal Size Press – Standard two-roll configuration
  • Vertical Size Press – Space-saving and suitable for high-speed machines
  • Gate Roll Size Press – Advanced design for better control and coverage

• Sizing Solutions:
  • Modified starch, carboxymethyl cellulose (CMC), synthetic resins, or specialty chemicals depending on paper grade

• Applications:
  • Writing & printing paper
  • Packaging and board grades
  • Paper requiring coating base preparation

• Benefits:
  • Improved surface strength and runnability
  • Enhanced print quality and ink absorption control
  • Increased resistance to penetration by liquids
  • Better bonding for coated and laminated papers

The size press significantly enhances the functional and aesthetic properties of paper, making it essential for value-added paper production.