Industrial Packaging – EVA Packaging Liner
Definition
EVA (Ethylene Vinyl Acetate Copolymer) is a copolymer of ethylene and vinyl acetate. Its Chinese chemical name is ethylene-vinyl acetate copolymer (or ethylene-acetic acid vinyl ester copolymer). Typically, the vinyl acetate (VA) content ranges from 5% to 40%. Compared to polyethylene (PE), EVA has reduced crystallinity due to the introduction of vinyl acetate monomers, which enhances its toughness, impact resistance, filler compatibility, and heat-sealing properties. It is widely used in foam shoe materials, functional greenhouse films, packaging films, hot-melt adhesives, wires and cables, toys, and more. In the new energy sector, it is also applied in photovoltaic materials and solar cell adhesives.
Properties
(1) Softness & Elasticity: EVA exhibits rubber-like elasticity and remains flexible even at -50°C.
(2) Optical & Chemical Properties: It has high transparency, surface gloss, and excellent chemical stability, with strong aging and ozone resistance. It is non-toxic.
(3) Processability & Shock Absorption: EVA is easily processed and molded, and its shock resistance surpasses polystyrene foam (EPS). Unlike traditional foam materials, it can be cut and shaped for protective packaging.
(4) Environmental Compliance: EVA meets eco-friendly standards, making it an ideal choice for export products.
(5) Density Versatility: Its wide density range allows for diverse applications.
II. Definition of EVA Packaging Liner
1. Definition
EVA packaging liners are inserts used inside metal boxes, paper gift boxes, whiteboard boxes, and plastic boxes to protect products (e.g., USB drives, jewelry, knives, precision instruments, and tools).
2. Classification
(1) By Foaming Type:
Eco-friendly coarse-celled EVA
Standard EVA
Food-grade odorless EVA
Flame-retardant EVA
Anti-static EVA
(2) By Hardness (Shore A):
25°, 38°, 45°, 50°, 60°, 70°, 80°
Common industrial uses:
38°–45° for foot pads
25°–38° for electronic components
(3) By Function:
Standard EVA liner
Flame-retardant EVA liner
Anti-static EVA liner
(4) By Color:
Black, white, and colored EVA liners
Industrial preference: Black and white (colored liners are less common)
III. Manufacturing Process of EVA Packaging Liners
1. Die-Cutting (Punching):
Uses a die and small press to cut EVA sheets.
Limitations:
Thickness >3cm may cause uneven edges and depressions around cutouts.
Not ideal for thick materials (e.g., 9cm requires layering).
2. CNC Carving:
Uses a CNC machine for precise, straight-edged cuts.
Advantage:
Can produce thick liners (e.g., 9cm) in one piece (no layering needed).
IV. Advantages of EVA Packaging Liners
(1) Water Resistance: Closed-cell structure prevents water absorption.
(2) Chemical Resistance: Resists seawater, oils, acids, alkalis, and bacteria.
(3) Ease of Processing: No seams, high toughness, and easy to heat-press, cut, glue, or laminate.
(4) Shock Absorption: High elasticity and tensile strength provide superior cushioning for impact protection.
(5) Thermal Insulation: Excellent heat/cold resistance (suitable for extreme temperatures).
(6) Eco-Friendly: Non-toxic, odorless, recyclable, and compliant with EU packaging regulations.
V. Applications of EVA Packaging Liners
EVA liners are widely used in:
Jewelry, ceramics, toolboxes, electronics, instruments
Gift boxes, toys, handicrafts, cosmetics, medical supplies
Hardware, wine, furniture, lighting, and other foam packaging fields
Note: This translation maintains technical accuracy while ensuring readability for industry professionals. Let me know if you need any refinements!
