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Views: 0 Author: Site Editor Publish Time: 2026-01-12 Origin: Site
Pentane-based systems are widely used for pipe insulation because they deliver low thermal conductivity, high compressive strength, and good dimensional stability. Below is a practical, application-focused guide.
Rigid foam for insulated pipes must have:
Low λ-value (excellent thermal insulation)
High compressive strength (radial & axial)
Good adhesion to steel / HDPE / aluminum
Dimensional stability over temperature cycling
Uniform cell structure in thick sections
Compatibility with pentane blowing agents
Polyester polyols are preferred over polyether polyols for these reasons.
| Property | Typical Range | Benefit |
|---|---|---|
| Hydroxyl value | 220–280 mg KOH/g | Strength & crosslink density |
| Functionality | 2.3–3.0 | Mechanical performance |
| Viscosity (25 °C) | Low–medium | Good flow in long pipe molds |
| Acid value | ≤ 1.5 mg KOH/g | Foam stability |
| Aromatic content | Medium–high | Higher rigidity & insulation |
| Pentane solubility | High | Stable foaming, fine cells |
| Blowing agent | Suitability |
|---|---|
| Cyclopentane | Best insulation & closed cells |
| iso-Pentane | Good flow, slightly higher λ |
| n-Pentane | Cost-effective, higher volatility |
➡ Cyclopentane is most commonly used for district heating, LNG, and cold-water pipelines.
Polyol side (B-side):
Pentane-compatible polyester polyol
Cyclopentane: 10–18 php
Silicone surfactant (pentane grade)
Amine + metal catalysts (balanced)
Optional flame retardant (TCPP / TEP)
Isocyanate side (A-side):
PMDI (index 105–115 for PUR)
PIR systems: index 180–250
| System | Application |
|---|---|
| PUR | Cold water, chilled water, HVAC pipes |
| PIR | District heating, hot oil, industrial pipes |
➡ PIR polyester polyols have higher aromatic content and support high-index formulations.
✔ Excellent pentane retention in thick walls
✔ Uniform foam rise in long pipe molds
✔ Higher compressive strength vs polyether
✔ Lower thermal conductivity over time
✔ Better adhesion to metal and plastic jackets
| Property | Typical Value |
|---|---|
| Free-rise density | 30–40 kg/m³ |
| Molded density | 45–65 kg/m³ |
| Closed-cell content | ≥ 90% |
| Compressive strength | ≥ 250 kPa |
| λ-value (initial) | ~22–24 mW/m·K |
Aromatic polyester polyols for cyclopentane pipe systems
Low-viscosity polyester polyols for continuous pipe production
PIR-grade polyester polyols for high-temperature insulation
(I can help match Stepan, Covestro, or Chinese grades based on your target density and pipe diameter.)
⚠ Pentane is flammable:
Explosion-proof foaming lines required
Good ventilation & gas monitoring
Control mold & raw material temperature
Pentane-foaming polyester polyols are the industry standard for insulated pipe systems because they deliver:
Superior insulation performance
Strong mechanical properties
Long-term dimensional stability
