Flame retardant solutions for thermoplastic elastomer TPE
When using aluminum hypophosphite (AHP) and melamine cyanurate (MCA) in thermoplastic elastomers (TPE) to achieve a UL94 V0 flame-retardant rating, it is essential to consider the flame-retardant mechanism, material compatibility, and processing conditions. Below is the recommended formulation:
1. Typical Loading When Used Individually
Aluminum Hypophosphite (AHP)
- Loading: 15-25%
- Characteristics: Promotes char formation, suitable for systems requiring high mechanical performance, but processing temperature should be controlled (recommended ≤240°C).
Melamine Cyanurate (MCA)
- Loading: 25-35%
- Characteristics: Relies on endothermic decomposition and gas dilution; high loading may reduce material flexibility.
2. Recommended Synergistic Blending Formula
AHP and MCA Blending Ratio
- AHP: 10-15%
- MCA: 10-20%
- Total loading: 20-30%
Advantages: Synergistic effect reduces total loading while minimizing impact on mechanical properties (e.g., tensile strength, elasticity).
3. Key Influencing Factors
- Base Material Type: SEBS-based TPEs are generally easier to flame-retard than SBS-based ones, allowing for slightly lower additive loading.
- Sample Thickness: UL94 V0 compliance is thickness-sensitive (1.6mm is more challenging than 3.2mm), so formulations must be adjusted accordingly.
- Synergists: Adding 2-5% nano-clay or talc can enhance char formation and reduce flame retardant loading.
- Processing Temperature: Ensure processing temperatures remain below the decomposition points of AHP (≤240°C) and MCA (≤300°C).
4. Recommended Verification Steps
- Preliminary Testing: Conduct small-scale trials with AHP 12% + MCA 15% (total 27%).
- Performance Testing: Evaluate flame retardancy (UL94 vertical burning), hardness (Shore A), tensile strength, and melt flow index.
- Optimization: If dripping occurs, increase AHP ratio (to enhance charring); if mechanical properties are poor, consider adding plasticizers or reducing total loading.
5. Precautions
- Avoid combining with acidic fillers (e.g., certain colorants), as they may destabilize AHP.
- If the TPE contains large amounts of oil-based plasticizers, flame retardant loading may need to be increased (oil can reduce flame retardancy efficiency).
Through rational blending and experimental optimization, UL94 V0 compliance can be achieved while balancing TPE processability and mechanical performance. Collaboration with flame retardant suppliers for customized solutions is recommended.
Sichuan Taifeng New Flame Retardant Co., Ltd. (ISO & REACH)
Wechat/ WhatsApp: +86 18981984219
lucy@taifeng-fr.com
Post time: May-22-2025
