MATERIALS
The transformed expandable materials essentially come from three families of plastics: polystyrene, polypropylene and polyethylene.
The characteristics and typical applications for each are listed below along with their properties - List of material Properties
Materials
EPS - Expanded polystyrene
Characteristics :
- Good quality/price ratio
- High energy absorption during impact
- Resistant to compression
- High thermal resistance (R-value)
Some applications :
- Custom packaging
- Standard packaging (protective corners)
- Antistatic packaging (Electro Static Discharge)
- Insulating panels
- Light structural components
- Isothermal containers (to maintain the cold chain)
EPP
- Expanded polypropylene
Characteristics :
- Flexible
- Resilient
- Solvent resistant
- Reusable
Some applications :
- Absorption systems in car bumpers
- Packaging for fragile and high-end electronic devices
- Reusable handling trays
- Custom protective padding for helmets
- Protective cases for instruments
- Flotation material
EPE
- Expanded polyethylene
Characteristics :
- Very flexible and resistant
- Soft, nonabrasive on delicate finishes
- Excellent reuse potential following multiple impacts
- Highly solvent resistant
- Insulating
Some applications :
- Flotation material
- Packaging for very delicate products
- Antistatic packaging for electronic components
- Seat padding
- Support for fragile components
- Comfort padding in sporting goods
Other copolymers
Characteristics :
- Superior strength
- Can be moulded to high densities
- Can be used at high temperatures (up to 255°F)
Some applications :
- Helmet padding
- Car interior components
- Sterilizable trays
- Furniture components
- Solar panels
Properties
Expanded plastics are also called cellular plastics. Once transformed, the small
beads are filled with air and fused together. At low densities they are
basically 98% air by volume. It is this unique characteristic that yields
exceptional performance in terms of shock absorption and thermal insulation.
Expanded resins can be used to mould parts that are either simple or complex in
shape, and in dimensions ranging from one inch to many feet. The transformation
process is safe and economical. Since steam is used to expand the resins,
virtually no odour or waste products are generated and everything is recycled.
Products made with expanded resins possess numerous properties, meaning they can
meet the requirements of a variety of applications, from packaging to light
structural components.
- Climatic protection (temperature variations, humidity protection and acoustic
insulation).
- Impact damping to prevent breakage caused by strong acceleration during
impact, fall or vibration.
- Uniform distribution of loads on resilient load-bearing surfaces.
- Filling material inside packaging.
- Quality packaging with a flexible design: light and rigid, the designed parts
fit together rapidly and precisely, plus allow for stable, secure stacking (for
easier assembly and handling and lower transport costs).
Here are some of the properties of expanded plastics (EPS, EPP and EPE) :
Thermal behaviour (excellent)
These materials are known for their superior insulating properties (R-value).
They are ideal products for ensuring climatic comfort and isothermal protection
(maintaining the cold chain). They are resistant to high temperatures between
160°F and 250°F (71°C and 121°C). They even withstand
applications at temperatures below –40° (F or C).
Permeability (low)
These materials are not hygroscopic (i.e., they do not easily absorb moisture).
Electrical properties (resistant)
These materials do not conduct electricity. They can also be treated to
dissipate electrostatic charges and so are suitable for antistatic packaging.
Chemical properties (stable)
All expanded resins are insensitive to water, alkaline washing powders and most
acids. They are stable when in contact with animal or vegetable fat as well as
anticorrosives containing paraffin. Some resins (EPP and EPE) are also
resistant to organic solvents and gasoline.
Mechanical properties (large range)
The different densities possible allow for a large range of performances.
Compression resistance can vary from very low (padding) to high (wood).
Products can be rigid or flexible. They can absorb vibrational energy as well
as the energy generated by large impacts or even multiple impacts.
UV radiation (slight degradation)
In direct and prolonged exposure to sunlight, expanded resins show slight
surface degradation in the form of a fine layer of dust. Black pigments can be
added to improve their durability with respect to UV rays.
Fire hazard behaviour (self-extinguishing)
Some types of materials are self-extinguishing, meaning they cannot maintain
combustion by themselves. However, untreated cellular materials are
combustible.
Contact with food
EPS, EPP and EPE do not have any effect on the taste or smell of food/products
with which they are in contact. When required, they are safe for use with
foodstuffs.
