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.