Why Adhesive Viscosity Monitoring Is Critical for Quality

Viscosity is one of the most important adhesive properties to monitor during production. Even small variations can significantly impact board quality and production efficiency.

How Viscosity Affects Performance

Too High Viscosity

Poor penetration into paper fibers

Uneven glue film application

Increased adhesive consumption

Risk of delamination

Too Low Viscosity

Excessive penetration into paper

Weak surface bond

Wet board and warping

Inconsistent gel temperature performance

Measuring Viscosity

Stein-Hall Cup Method

Most common in corrugating industry. Measures time for adhesive to flow through a standardized funnel. Typical targets: 30-60 seconds.

Rotational Viscometer

More precise measurement using spinning spindle. Better for R&D and troubleshooting.

Factors Causing Viscosity Changes

1. Temperature: Higher temp = lower viscosity

2. Water evaporation: Increases viscosity over time

3. Bacterial growth: Can break down starch, reducing viscosity

4. Preparation errors: Incorrect mixing ratios

5. Aging: Fresh adhesive differs from aged

Best Practices for Viscosity Control

Monitoring Schedule

Check at preparation (verify target viscosity)

Check every 2 hours during production

Check after any process changes

Log all readings for trend analysis

Adjustment Guidelines

Add water carefully to reduce viscosity

Prepare fresh adhesive if viscosity too low

Maintain consistent temperature in glue pans

Use covered pans to reduce evaporation

Quality Correlation

Track viscosity readings alongside quality data (bond strength, delamination incidents) to identify optimal ranges for your specific operation.

Xuegong adhesive powders are formulated for consistent viscosity development when mixed according to specifications.