EVA Foam Deep Dive

1. Fundamental Material Characteristics

Chemical Composition and Structure

• Ethylene-Vinyl Acetate Copolymer (EVA), Vinyl Acetate (VA) content: 5%-40%
• Closed-cell foam structure, density range: 0.03-0.25 g/cm³, customizable hardness (Shore C 15-80)

Key Physical Properties

Property	Value Range	Industry Impact
Reboundedness	40%-65%	Determines cushioning performance
Compression Set	10%-35% (22h@70°C)	Impacts service life
Temperature Resistance	-50°C to 80°C	Applicable environment range
Water Absorption	<1%	Key waterproof property
Tear Strength	3-8 kN/m	Mechanical durability indicator

2. Special Modified Varieties

1. Anti-Static EVA
   • Surface resistance: 10^6-10^9Ω, for electronic product packaging
   • Added carbon nanotubes or permanent anti-static agents
2. Flame-Retardant EVA
   • UL94 V-0 rating, oxygen index >28%
   • Aluminum/Magnesium hydroxide composite flame retardant system
3. High-Rebound EVA
   • Reboundedness >60%, for sports shoe midsoles
   • Peroxide cross-linking foaming technology

3. In-Depth Industry Applications

New Energy Vehicle Sector

• Battery cushion pads: Thermal conductive EVA (0.6-1.2 W/m·K)
• Requirements: UL94 V-0 rating, resistant to coolant corrosion

Medical Device Applications

• Medical device packaging: Complies with ISO 11607 requirements
• Surgical positioning pads: Biocompatibility testing (ISO 10993)

High-End Sports Equipment

Surfboard filling: Closed-cell ratio >90%, excellent waterproofness

Sports shoe midsoles: Energy return rate >65%

4. Processing Technology Comparison

Process Type	Applicable Products	Min Thickness	Tolerance Control
Compression Molding	Footwear/Sporting Goods	2mm	±0.3mm
Continuous Extrusion	Rolls/Sheets	0.5mm	±0.15mm
Precision Die-Cutting	Electronic Gaskets	0.3mm	±0.1mm

5. Quality Control Standards

• Automotive Industry: IATF 16949 system, PPAP certification
• Medical Industry: ISO 13485, biocompatibility testing
• Electronics Industry: ESD S20.20 anti-static standard

6. Technology Development Trends

Smart Manufacturing: AI visual inspection of cell uniformity

Green Environmental Protection: Bio-based EVA (sugarcane ethanol extraction)

Functional Integration: Thermal conductive-flame retardant-EMI shielding multifunctional composites

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