The material of air cushion systems (风袋) is not a single-component structure but a composite of three functional layers—base material, coating, and reinforcement layer—each serving specific roles to achieve the unique performance of "flexible yet tough, dense yet lightweight."
1. Base Material: TPU Film – The "Golden Balance" of Flexibility & Strength
The main body of the air cushion typically uses thermoplastic polyurethane (TPU) film with a thickness of 0.15–0.3 mm. TPU’s molecular structure alternates between soft segments (polyester/polyether polyols) and hard segments (diisocyanates), creating a "soft-hard alternating" architecture that delivers dual advantages:
- Flexibility: The soft segments’ freely rotating chains allow the film to bend 180° without cracking, conforming seamlessly to complex seat contours.
- Strength: The hard segments form physical crosslinks like "microscopic scaffolds," enabling a tensile strength of 30–50 MPa (1/5 of steel wire) to withstand human body pressure without deformation.
TPU also offers exceptional:
- Oil resistance (resists oil penetration from seat leathers).
- UV aging resistance (no yellowing after 5 years of sun exposure).
- Recyclability (aligning with automotive industry sustainability trends), making it the ideal base material choice.
2. Coating: PU or Silicone – The "Dual Shield" for Airtightness & Protection
To enhance airtightness and chemical resistance, TPU films are coated with polyurethane (PU) or silicone layers (5–10 µm thick), each with distinct roles:
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PU Coating:
- Forms a dense crosslinked network via chemical reactions, reducing gas leakage to <0.1 cc/m²·h (equivalent to 1 mL air loss per 1 m² film over 24 hours), ensuring ventilation efficiency.
- Contains antistatic agents to minimize dust adhesion, maintaining surface cleanliness.
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Silicone Coating:
- Low surface energy (contact angle >110°) creates a "lotus effect," causing water droplets to roll off and preventing condensation ingress.
- Wider temperature tolerance (-60°C to 200°C), suitable for extreme climates.
3. Reinforcement Layer: 3D Woven Mesh – The "Invisible Skeleton" Against Collapse
In critical areas (e.g., seat frame contact points), a 3D woven mesh fabric (polyester-spandex blend) is embedded, providing three key functions through its three-dimensional structure:
- Collapse Resistance: Prevents over-inflation deformations to maintain airflow pathways.
- Pressure Distribution: Elastic deformation evenly disperses body pressure, avoiding localized stress points that could rupture the film.
- Breathability: Porous design enables "micro-ventilation" for enhanced seating comfort.
