How To Select Raw Materials For HR Foam?

High resilience polyurethane foam (HR foam) is widely used in mattresses, car seats, and upholstered furniture due to its excellent elasticity, comfort, and durability. Its performance largely depends on the composition and ratio of the polyurethane system used. Therefore, selecting the right raw materials is essential to ensure foam quality and stable production.

I. Main Raw Material Selection

1.Polyether Polyol (Base Polyol)

Function & Role: Forms the foam's main structure, determining softness, resilience, and mechanical properties.

Common Types: High molecular weight trifunctional polyether polyols (e.g., 330N, 4110, 5601).

Selection Points:

*Hydroxyl value between 25–35 mgKOH/g to support open-cell formation

*Moderate viscosity for better metering and mixing

*Free of impurities and moisture to reduce foam defects

2.Polymer Polyol (Reinforced Polyol)

Function & Role: Enhances load-bearing capacity and mechanical strength of foam.

Common Types: Polymer polyols containing polystyrene or polyacrylonitrile particles (e.g., 803, C series).

Selection Points:

*Good dispersion and stable suspension

*Does not reduce cell openness

*High compatibility with base polyol

II. Key Additives Selection

1.Silicone Surfactant (Silicone Oil)

Function & Role: Controls foam cell structure, prevents collapse and cell coalescence.

Recommendation: Use hydrolysis-resistant, moderately active and stable silicone oils (e.g., L series, B series).

Notes: Must match the polyol system; select non-separating types.

2.Catalyst

Function & Role: Accelerates reaction between isocyanate and water/polyol, controls reaction time and curing speed.

Common Types:

*Tertiary amines: A33 (for foaming), DMEA (for balancing reaction rate)

*Organotin compounds: A1, T9 (for gelling)

Selection Advice:Use a balanced catalyst system;Control dosage to avoid premature closed cells or excessive heat

3.Crosslinker

Function & Role: Increases structural crosslinking points, improving thermal stability and compression performance.

Common Types: Diethanolamine (DEA), Trimethylolpropane (TMP)

Selection Focus: Good stability, no precipitation, low volatility

4.Blowing Agent (Physical/Chemical)

Function & Role: Generates gas to create foam cells. HR systems generally use chemical blowing agents.

Common Type: Deionized water

Control Tips:

Strict control of water dosage (error < ±0.1 parts)

Avoid water carrying impurities that may affect the reaction

5.Cell Opener (Degassing Aid)

Function & Role: Controls cell openness, facilitates gas escape, improves elasticity and breathability.

Common Types: C225, Y10366

Selection Advice:

Use low-dosage, high-efficiency types

Ensure compatibility with silicone oils to prevent interaction

III. Raw Material Selection Notes

1.Stability First: Material stability determines the shelf life of the polyol blend.

2.Compatibility Match: All additives must be compatible with the base polyol to prevent separation or sedimentation.

3.Environmental Consideration: Prefer low-VOC, low-odor, halogen-free eco-friendly additives.

4.Supply Reliability: Work with reputable suppliers with strong technical support to ensure batch consistency.