EVA

The material. Ethylene-Vinyl-Acetate elastomers (EVA) are built around polyethylene. They are soft, flexible, and tough and retain these properties down to -60°C and have good barrier properties as well as FDA approval for direct food contact. EVA can be processed by most normal thermoplas­tic processes: co-extrusion for films, blow molding, rotational molding, injection molding, and transfer molding.

Composition

(CH2)n-(CH2-CHR)m

General properties

Density

945

– 955

kg/m3

Price

*2.1

– 2.31

USD/kg

Mechanical properties

Young’s modulus

0.01

– 0.04

GPa

Yield strength (elastic limit)

12

– 18

MPa

Tensile strength

16

– 20

MPa

Compressive strength

13.2

– 19.8

MPa

Elongation

730

– 770

%

Fatigue strength at 107 cycles

*12

– 12.8

MPa

Fracture toughness

*0.5

– 0.7

MPa. m1/2

Thermal properties

Glass temperature

* -73.2

– -23.2

°C

Maximum service temperature

46.9

– 51.9

°C

Thermal conductor or insulator?

Good insulator

Thermal conductivity

0.3

– 0.4

W/m. K

Specific heat capacity

*2000

– 2200

J/kg. K

Thermal expansion coefficient

160

– 190

p, strain/°C

Electrical properties

Electrical conductor or insulator?

Good insulator

Electrical resistivity

*3.1 X 1021 –

1 X 1022

pnhm. cm

Dielectric constant

2.9 –

2.95

Dissipation factor

0.005 –

0.022

Dielectric strength

26.5 –

27 106

V/m

EVA is available in pastel or deep hues; it has good clarity and gloss. It has good barrier properties, little or no odor, and UV resistance.

Ecoproperties: material

Embodied energy, primary production

*86.7

– 95.8

MJ/kg

CO2 footprint, primary production

*2.88

– 3.19

kg/kg

Water usage

*96.4

– 289

l/kg

Ecoproperties: processing

Polymer molding energy Polymer molding CO2

7.4 – 8.84 MJ/kg

0.592 – 0.707 kg/kg

Recycling

Embodied energy, recycling CO2 footprint, recycling Recycle fraction in current supply

Typical uses. Medical tubes, milk packaging, beer dispensing equipment, bags, shrink film, deep freeze bags, co-extruded and laminated film, clo­sures, ice trays, gaskets, gloves, cable insulation, inflatable parts, running shoes.