10. Surface Brittleness & Powdering

Phenomenon: Surface crumbles easily upon touch.

Causes: Excess moisture forming excessive urea linkages, low isocyanate index.

Solutions:

· Strictly control moisture in polyol component, or adopt water-foaming dedicated catalysts.

· Increase isocyanate index to 1.08–1.12.

11. Poor Fluidity (Local Voids)

Phenomenon: Incomplete filling at special profile sections.

Causes: High viscosity of composite material, excessively short cream time, unreasonable material distribution.

Solutions:

· Reduce composite material viscosity (limit high-hydroxyl-value polyether).

· Extend cream time to 20–30 seconds.

12. Strong Pentane Odor (Environmental & Safety Hazards)

Phenomenon: Severe workshop odor and excessive VOC emission.

Causes: Incomplete foaming, open-cell foam surface, inadequate post-curing.

Solutions:

· Raise isocyanate index above 1.10.

· Prolong post-curing period to promote complete pentane reaction.

13. Rapid Combustion (Failed Flame Retardancy)

Phenomenon: Low oxygen index and substandard combustion performance.

Causes: Poor compatibility between flame retardant and pentane system, flame retardant migration, insufficient dosage.

Solutions:

· Increase dosage of flame retardants (e.g. TCPP, DEEP) or flame-retardant polyester content.

· Avoid powder flame retardants incompatible with pentane system.

14. Foam Brittleness (Poor Toughness)

Phenomenon: Foam cracks upon bending.

Causes: Excessively high crosslinking degree, high-functionality polyols, over-high isocyanate index.

Solutions:

· Introduce flexible polyether (e.g. molecular weight 2000).

· Control index at 1.05–1.08.

15. Uneven Surface (Orange Peel & Wavy Surface)

Phenomenon: Orange peel texture or wave patterns on panel surface.

Causes: Mismatched cream time and production line speed, inadequate mixing.

Solutions:

· Adjust cream time according to line speed (15–20 s for 5–7 m/min line speed).

· Regularly clean the mixing head on schedule.

16. Moisture Condensation between Foam and Facings

Phenomenon: Water droplets visible after peeling.

Causes: Facing temperature below dew point, excessive moisture in raw materials.

Solutions:

· Preheat facings above 25℃.

· Strictly control moisture content of polyol component.

17. Post-expansion of Foam

Phenomenon: Excessive panel thickness after cutting.

Causes: Insufficient post-curing, slow reaction rate of system.

Solutions:

· Increase post-curing temperature to 60–70℃.

· Boost trimerization catalyst dosage.

18. Poor Batch-to-Batch Stability

Phenomenon: Unstable product quality between consecutive batches with identical formula.

Causes: Property variation of polyol batches, pentane volatilization loss, catalyst weighing deviation.

Solutions:

· Conduct small-scale trial before mass production for each raw material batch.

· Adopt nitrogen sealing for pentane storage tank to prevent volatilization.

· Pre-dilute catalysts before batching and addition.

If you have encountered with other problems, feel free to connect with us. Qichen has been providing blend polyol system for over 13 years. We have a team of well-experienced technical team to be at your serivce.