Name: Castor Oil Renewable Polyol for Eco PU Adhesives
Brand: Coatingsink
SKU: castor-oil-renewable-polyol-adhesive
Availability: InStock

Question 1

What is the functionality of this castor oil polyol and how does it affect crosslink density?

Accepted Answer

Castor oil has an average functionality of approximately 2.7 due to its ricinoleic acid content (~87%). This near-trifunctional character produces moderately crosslinked PU networks with good cohesive strength and flexibility — suitable for flexible laminating adhesives where some chain mobility is needed.

Question 2

Is moisture control critical when processing castor oil polyol with MDI or TDI?

Accepted Answer

Yes. Moisture content must be kept below 0.1% (1000 ppm) before isocyanate addition. Residual water reacts with isocyanate to generate CO₂, causing foam defects and reducing bond strength. Dry the polyol at 100–110°C under vacuum for 1–2 hours if the moisture value exceeds spec.

Question 3

Can this polyol be blended with synthetic polyester or polyether polyols?

Accepted Answer

Yes. Castor oil is fully miscible with most polyester polyols and compatible with many polyether polyols at up to 30–50 wt% loading. Blending with a linear polyester polyol (e.g. adipate-based, OH value 50–60) reduces viscosity and lowers the bio-based content proportionally while fine-tuning mechanical properties.

OH Value	160–165 mg KOH/g
Acid Value	≤2.0 mg KOH/g
Functionality	~2.7 (trifunctional)
Moisture Content	≤0.1%
Viscosity (25°C)	650–750 mPa·s

Castor Oil Renewable Polyol for Eco PU Adhesives

Specifications

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