Name: Polyether Polyol 2000 MW for Sealants
Brand: Coatingsink
SKU: polyether-polyol-sealant-pp2000
Availability: InStock

Question 1

What is the hydroxyl value of Polyether Polyol 2000 MW and how does it affect isocyanate stoichiometry?

Accepted Answer

The hydroxyl value is 54–58 mgKOH/g, consistent with a difunctional PPG of Mn ~2000. Use this to calculate NCO:OH index; at index 1.05–1.10 with 4,4′-MDI (NCO 33.6%), expect approximately 0.087–0.090 g MDI per gram of polyol for a slightly isocyanate-rich system, which minimises moisture sensitivity in the cured sealant.

Question 2

Does this polyol require pre-drying before compounding with isocyanates?

Accepted Answer

Yes. Water content must be ≤500 ppm (0.05%) before reaction with isocyanates; excess moisture generates CO₂ causing voids and reduced tensile strength. Dry under vacuum at 80°C for 2–3 hours, or strip with 3Å or 4Å molecular sieves if the material has absorbed atmospheric humidity during storage or transfer.

Question 3

What chain extenders are compatible with this polyol in two-component polyurethane sealant systems?

Accepted Answer

MOCA (4,4′-methylenebis(2-chloroaniline)) and DMTDA are standard chain extenders for two-component systems based on this polyol. Short-chain diols such as 1,4-butanediol or ethylene glycol raise crosslink density and Shore A hardness at the cost of low-temperature flexibility. For one-component moisture-cure systems no chain extender is needed; the isocyanate-terminated prepolymer cures directly with atmospheric moisture.

Acid Value	≤0.05 mgKOH/g
Functionality	2.0
Water Content	≤0.05%
Hydroxyl Value	54–58 mgKOH/g
Viscosity (25°C)	200 mPa·s

Polyether Polyol 2000 MW for Sealants

Specifications

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