Corrugated Board Delamination: Causes, Prevention, and Solutions

Delamination — the separation of paper layers in corrugated board — is one of the most common and costly quality problems in corrugated box production. This guide explains the causes and provides practical solutions for preventing and fixing delamination issues.

Understanding Delamination

What Is Delamination?

Delamination occurs when the bond between paper layers fails, causing the liner to separate from the fluting medium or the layers of a multi-wall board to come apart. This can happen immediately after production or later during storage, converting, or use.

Types of Delamination

Wet-end delamination: Bond fails before fully curing

Dry delamination: Separation occurs after board has dried

Edge delamination: Separation at board edges

Spot delamination: Localized areas of poor bonding

Converting delamination: Separation during printing or die-cutting

Common Causes

1. Adhesive Issues

Insufficient Adhesive Application

Gap too large between glue roll and corrugating roll

Glue dam settings incorrect

Adhesive viscosity too low

Glue roll worn or damaged

Poor Adhesive Quality

Incorrect gel point temperature

Inadequate tack or green bond strength

Adhesive degradation from age or contamination

Wrong adhesive formula for paper types being used

2. Machine Settings

Temperature Problems

Preheater temperature too low

Hot plate temperature insufficient

Uneven heat distribution across web

Heat transfer compromised by dirty surfaces

Pressure Issues

Pressure roll settings incorrect

Uneven pressure across web width

Worn belts or pads

Belt tension improper

Speed vs. Capacity

Running too fast for heat and adhesive to work

Inadequate dwell time on hot plates

Speed changes without corresponding adjustments

3. Paper Quality

Moisture Content

Paper too dry (won't accept adhesive)

Paper too wet (adhesive diluted)

Moisture variation across web

Different moisture levels between liner and medium

Surface Issues

Sizing or coating interfering with adhesive penetration

Contamination on paper surface

Recycled fiber content affecting porosity

Prevention Strategies

Adhesive Management

Maintain correct viscosity (check regularly with cup)

Keep gel temperature consistent and appropriate

Use fresh adhesive (don't let it degrade in tank)

Match adhesive formula to paper types

Consider alkali-free adhesive for better consistency

Machine Setup

Regular temperature calibration and verification

Consistent pressure roll settings

Proper belt maintenance and tension

Clean heat transfer surfaces regularly

Establish standard operating procedures for each board type

Paper Handling

Control paper storage conditions

Allow paper to acclimate before use

Monitor and record paper moisture content

Work with paper suppliers on consistency

Testing and Quality Control

Pin adhesion test (PAT) for immediate bond check

Ply bond test for cured board strength

Regular adhesive testing

Document settings and results for reference

Solutions for Existing Problems

Immediate Steps

Check and adjust adhesive viscosity

Verify temperatures at all heat sources

Inspect glue application pattern

Review recent changes to materials or settings

Systematic Approach

Test one variable at a time

Document changes and results

Check paper supplier consistency

Evaluate adhesive performance

When to Consider Adhesive Change

If delamination persists despite machine adjustments, the adhesive formula may need revision. Xuegong's alkali-free adhesive products are engineered for consistent bond strength and easier process control. Contact our technical team for adhesive evaluation and recommendations.