Preventing Corrugated Board Delamination

Delamination—separation of the liner from the fluted medium—is one of the most serious quality defects in corrugated board. It compromises box strength and can lead to customer complaints and returns.

Types of Delamination:

Single Facer Delamination: Liner separates from medium immediately after the single facer. Usually visible as bubbles or loose areas.

Double Backer Delamination: Bond failure between single-face web and liner at the double backer. May not appear until cutting or handling.

Delayed Delamination: Board appears good initially but delaminates during storage or use. Often caused by moisture-related stress.

Common Causes:

Adhesive Issues:

• Insufficient adhesive application

• Adhesive viscosity too high (poor penetration)

• Adhesive temperature incorrect

• Gel temperature too high or too low

• Contaminated or old adhesive

Process Issues:

• Insufficient pressure at bond point

• Line speed too fast for adhesive to set

• Inadequate heat for gelatinization

• Poor paper-to-roll contact

Paper Issues:

• Paper surface treatments repelling adhesive

• High-ash recycled papers with poor bonding

• Excessive moisture in paper rolls

Diagnostic Approach:

1. Identify where delamination is occurring (SF or DB)

2. Check adhesive application uniformly across web

3. Verify adhesive preparation (viscosity, temperature)

4. Test paper for surface treatments or contamination

5. Review recent process or material changes

Solutions:

• Optimize adhesive viscosity for paper type

• Ensure proper gel temperature (58-62°C typical)

• Adjust pressure and gap settings

• Consider switching to instant-setting adhesive

• Work with paper supplier on bonding issues