Hot Sale Spraying Rigid Foam Polyester Polyol NXF-400

Product Overview

NXF-400 is a rigid foam polyester polyol. It is a polyester polyol made from materials such as diethylene glycol and phthalic anhydride. The polyester polyol products of this series produced by our company feature high reactivity, good stability, moderate molecular weight and no stratification during long-term storage, among other excellent comprehensive properties.

For spray polyurethane foam (SPF), the polyester polyol you choose has a big impact on reactivity, adhesion, dimensional stability, and fire performance. 

What Spraying Foam Needs from a Polyester Polyol

Compared with slabstock or boardstock, spray foam requires polyols that provide:

• Fast but controllable reactivity (short cream & gel time)

• Good adhesion to concrete, metal, wood

• High crosslink density for rigidity

• Thermal and fire performance (especially PIR spray)

• Manageable viscosity for spray equipment

Recommended Polyester Polyol Types for Spray Foam

Aromatic Polyester Polyols (Most Common)

Best for:

• Closed-cell SPF

• Roofing spray foam

• PIR spray insulation

Typical properties

• OH value: 200–400 mg KOH/g

• Functionality: 2.5–3.5

• Viscosity: 1,500–5,000 cP @25 °C

Advantages

• Excellent rigidity

• Better fire performance than polyether polyols

• Strong adhesion

• Cost-effective

Modified Aromatic Polyester Polyols

Used when you need:

• Lower viscosity for easier spraying

• Better B-side compatibility

• Improved dimensional stability

Often blended with:

• Low-viscosity polyether polyols

• Reactive flame retardants

Polyester Polyol vs Polyether Polyol in SPF

Closed-cell SPF & PIR → Polyester polyol dominant
Open-cell SPF → Mostly polyether polyol

Typical Polyester Polyol Role in Spray Formulation

In a closed-cell spray foam B-side, polyester polyol usually makes up:

• 30–70% of total polyol blend

Blended with:

• Polyether polyol (processing & flexibility)

• Flame retardants

• Catalysts (amine + potassium for PIR)

• Surfactants

• Blowing agents (HFO / water)

Prameters

Summary Recommendation

If your target is:

• Closed-cell SPF insulation → Aromatic polyester polyol (OH 220–260)

• PIR spray foam / roofing → Higher OH aromatic polyester polyol

• Easy spraying + balanced performance → Modified aromatic polyester polyol blend