Name: 1,4-Butanediol Chain Extender for PU Adhesives
Brand: Coatingsink
SKU: bdo-chain-extender-pu-adhesive
Availability: InStock

Question 1

How does BDO chain extender dosage affect hard-segment content and adhesive performance?

Accepted Answer

Increasing BDO loading raises the hard-segment fraction, which improves tensile strength, cohesive modulus, and heat resistance. However, excessive hard-segment content reduces flexibility and low-temperature peel strength. Typical BDO/polyol molar ratios in laminating adhesives range from 0.5:1 to 2:1 — optimize against the target R value (NCO/(OH + NH) = 1.00–1.05).

Question 2

Why is moisture control especially critical for BDO compared to higher-MW polyols?

Accepted Answer

BDO's high OH value (≈1247 mg KOH/g) means even trace moisture represents a significant mole-fraction of the reactive hydroxyl pool. At 500 ppm water, roughly 0.03 mol H₂O per 100 g BDO competes with isocyanate, producing CO₂ and urea linkages that disrupt hard-segment ordering. Use BDO stored under nitrogen and dried to ≤0.05% moisture before formulating.

Question 3

Is BDO a solid at room temperature and how should it be handled?

Accepted Answer

BDO has a melting point of 20–21°C, meaning it may solidify in cool storage. Maintain drummed material above 25°C or gently warm to 40–50°C to reliquefy before use. Avoid overheating; prolonged exposure above 100°C can cause dehydration to tetrahydrofuran (THF). Handle under inert atmosphere to prevent moisture uptake.

OH Value	1240–1250 mg KOH/g
Purity (GC)	≥99.5%
Color (APHA)	≤10
Melting Point	20–21°C
Moisture Content	≤0.05%

1,4-Butanediol Chain Extender for PU Adhesives

Specifications

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