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