Rigid Foam Polyester Polyol For PIR Panels

Rigid foam polyester polyols for PIR (Polyisocyanurate) panels are mainly used to produce high-performance thermal insulation boards and sandwich panels for cold storage, industrial buildings, roofing, and wall insulation systems. These polyester polyols are typically aromatic polyester polyols with high hydroxyl values and are reacted with polymeric MDI at a high isocyanate index to form PIR structures.

Key Characteristics of Polyester Polyols for PIR Panels

Typical properties include:

High aromaticity improves:

• Fire resistance

• Char formation

• Dimensional stability

• Compressive strength

• Thermal insulation performance

These are important for PIR sandwich panels used in construction and refrigeration.

Main Applications of PIR Panel Polyester Polyols

1. Continuous PIR Sandwich Panels

Used in:

• Cold rooms

• Industrial wall panels

• Roofing panels

• Clean rooms

Benefits:

• Excellent adhesion to metal facings

• Good foam flowability

• Uniform cell structure

• Low thermal conductivity (low lambda)

2. Discontinuous / Batch Panels

Suitable for:

• Custom insulated panels

• Refrigerated truck panels

• Pipe insulation sections

3. Refrigeration & Cold Storage

PIR foams provide:

• Better thermal efficiency

• Higher dimensional stability at low temperature

• Improved moisture resistance

4. Fire-Resistant Construction Panels

PIR chemistry forms isocyanurate rings, improving:

• Flame resistance

• Smoke suppression

• Thermal stability up to ~140–200°C depending on formulation

Common Raw Materials

Polyester Polyol Types

• Phthalic anhydride based polyester polyols

• PET recycled aromatic polyester polyols

• Terephthalic acid based polyester polyols

Isocyanate

Usually:

• Polymeric MDI (pMDI)

Blowing Agents

Common options:

• Cyclopentane

• n-Pentane / Iso-pentane blends

• HFO blowing agents

• HCFC-141b (being phased out globally)

Catalysts

Common catalysts include:

• DMCHA

• TEDA

• DMAEE

• Stannous Octoate

Catalyst selection strongly affects PIR trimerization, cure speed, adhesion, and panel dimensional stability.

Typical PIR Panel Formulation Example

Example rigid PIR panel formulation:

Higher PIR index improves:

• Fire performance

• Heat resistance

• Char strength

But excessive index may increase brittleness.

Advantages of Polyester Polyol in PIR Panels

Compared with polyether systems:

Common Commercial PIR Polyester Polyols

Examples include:

• Stepan Company STEPANPOL® series

• Dow Inc. VORATHERM™ FF series

• Huntsman Corporation DALTOPIR® systems

• Synthesia Technology aromatic polyester polyols

• Esterpol rigid foam polyester polyols

Processing Technologies

PIR panels are commonly produced by:

• Continuous double-belt lamination lines

• High-pressure foaming machines

• Pentane-compatible systems

Critical process parameters:

• Cream time

• Gel time

• Tack-free time

• Core density

• Panel adhesion

• Cell uniformity

8. Parameters