XH-1698 Silicone Surfactant Specialized for LNG Ultra-Low Temperature Insulation Rigid Foam

Overview of LNG Service Conditions

1. PUR polyurethane rigid foam: Used for LNG transport tank trucks and small pipeline insulation
2. PIR polyisocyanurate foam: The primary material for LNG storage tanks and large pipelines, complying with GB/T 39936

Core Design Requirements of LNG-Grade Silicone Surfactant

1. Mandatory Molecular Structure Specifications

• Adopt hydrolysis-resistant polyether-modified siloxane with Si-C bonds; avoid low-cost silicones with Si-O-C ester linkages which break down under long-term storage or trace moisture
• Precisely balanced EO/PO ratio to deliver great compatibility with low-GWP blowing agents including LBA, cyclopentane and 245fa
• Enhanced toughness of interfacial film: Foam cell walls withstand drastic temperature swings from ambient temperature down to -162℃, preventing spontaneous cell rupture that causes higher open-cell ratio and thermal conductivity drift

2. Critical Target Foam Performance Indicators (Minimum Standards for LNG Insulation)

• Fine, uniform cell structure with pore size between 80–150 μm, no uneven pore distribution
• Initial closed-cell ratio ≥93%; closed-cell retention ≥90% after cryogenic cycling (core benchmark)
• Minimal dimensional change at low temperature to eliminate shrinkage and cracking under ultra-cold conditions
• Stable low thermal conductivity; zero silicone migration, no negative impact on adhesion between foam and metal tanks

Formulation Compatibility Guidelines (Focus on LBA Blowing Agent Systems)

1. Recommended dosage: 1.8–2.8 phr in polyol blend (higher than standard construction rigid foam)
    
   LBA has different solubility properties compared with traditional HCFCs, requiring extra surfactant to stabilize gas-liquid interfaces.
2. Application-specific formulation tuning

• Cast-molded LNG panels: Prioritize flowability; the surfactant balances filling performance and foam stabilization
• On-site spray coating for LNG pipelines: Anti-fogging performance prevents surface crusting and large surface pores

3. Incompatible combinations to avoid

• High-moisture polyol blends: Water content must be strictly controlled below 0.25%; silicone surfactant cannot offset defects caused by excess water
• Large amounts of high-viscosity polar polyester polyols: Complete a 48-hour low-temperature compatibility test to ensure no turbidity or delamination at 5℃ before formal use

Mandatory Validation Tests for LNG Insulation Projects

1. Ambient tests: Density, closed-cell ratio, thermal conductivity
2. Low-temperature aging test: 24-hour hold at -160℃, re-test closed-cell ratio (≥90% retention = pass)
3. Thermal cycling test: 5–10 cycles between 25℃ and -160℃, inspect for cracking and shrinkage