EPS, or Expandable Polystyrene: a thermoplastic product that is lightweight, strong, and offers excellent thermal insulation, making it ideal for the packaging and construction industries.
EPS, or Expandable Polystyrene: a thermoplastic product that is lightweight, strong, and offers excellent thermal insulation, making it ideal for the packaging and construction industries.
EPS is among the biggest commodity polymers produced in the world. EPS is a solid foam with a unique combination of characteristics, like lightness, insulation properties, durability and an excellent processability. EPS is used in many applications like thermal insulation board in buildings, packaging, cushioning of valuable goods and food packaging.
EPS has been a material of choice for over half a century because of its technical versatility, performance and cost effectiveness. It is widely used in many everyday applications where its light weight, strength, durability, thermal insulation and shock absorption characteristics provide economic, high performance products.
Light weight
EPS is an extremely lightweight material which is not surprising considering it is comprised of ~95% air. This characteristic makes it ideal for use in packaging as it does not significantly add to the weight of the total product thereby reducing transportation costs. Energy consumption for transport fuel is also reduced and vehicle emissions minimised – all contributing to lower global warming.
Durability
The exceptional durability of EPS makes it an effective and reliable protective packaging for a wide range of goods. The cellular structure of EPS makes it dimensionally stable and therefore does not deteriorate with age. EPS is also odourless and non-toxic.
Moisture resistance
EPS is a closed cell material and does not readily absorb water. There is no loss of strength in damp conditions, making EPS ideal for cool-chain products. The material is moisture resistant, so the highest hygiene requirements are met. The ability of EPS to resist moisture also lends itself for use in fishing floats and marina buoys. Even when subjected to prolonged saturation in water, EPS will still maintain its shape, size, structure and physical appearance with only a slight reduction to its thermal performance.
Thermal efficiency
The superior thermal efficiency of EPS makes it ideal for packaging any product that is sensitive to temperature change. Products enclosed in EPS containers can be maintained for long periods at temperature above or below ambient conditions and can be protected from sudden temperature changes that can occur in the transport through different climatic zones. Examples include fresh produce and seafood as well as pharmaceutical and medical products.
Shock absorption
EPS exhibits excellent shock absorbing characteristics making it the first choice for packaging of a wide range of products including appliances, electronic products, computers and chemicals.
Versatility
EPS can be manufactured to almost any shape or size, or it can be easily cut and shaped when required to suit any application. EPS is also produced in a wide range of densities providing a varying range of physical properties. These are matched to the various applications where the material is used to optimise its performance. In addition, EPS is also compatible with a wide variety of materials.
Ease of use
For building and construction applications, EPS is considered to be one of the easiest materials to install on site. It is normally supplied in sheet form however can also be moulded into shapes or in large blocks.
Building & Insulation applications
EPS resins are among the most popular materials for building and construction applications. EPS insulation foam are used in closed cavity walls, roofs, floor insulation and more. With its excellent price/performance ratio EPS is also used in pontoons and road construction. In addition to its traditional insulation application in the construction industry, EPS foam also finds a wide use in civil engineering and building: road foundations, void forming, flotation, drainage, impact sound insulation, modular construction elements, cellular bricks, etc. They all exploit the excellent mechanical properties of EPS combined with fast construction / assembly and low subsequent maintenance.
Packaging applications
Eggs, meat, fish and poultry. Cold drinks or carry-out meals. All these products are safely packed with EPS packaging materials; by doing so spoilage of foods is prevented. In the western world a combination of good packaging, refrigeration and transportation ensures that only two percent of food is lost through spoilage, compared with 50 percent in developing countries.
No matter what your products package, EPS have long been recognized as a versatile and cost-effective solution for foods and goods packaging.
Expensive TV's and all kind of IT equipment travel safely from the production line to the consumer's houses. EPS is the leading choice for electronic goods cushioning.
Other applications
Apart from the typical application in construction and packaging, EPS protective qualities can also be used in crash helmets - protecting the heads and potentially the lives of cyclists, or into surface and other decoration ranging from simple printing of a brand name to an elaborate pictorial representation achieved by mould engraving, or for fun and sports with e.g. windsurfing board.
EPS is manufactured from styrene monomer; low levels of styrene occur naturally in many plants, fruit, vegetables, nuts and meat. EPS is a derivative of ethylene and benzene and is made using a polymerisation process which produces translucent spherical beads of polystyrene, about the size of sugar granules. During this process a low boiling point hydrocarbon, usually pentane gas, is added to the material to assist expanision during subsequent processing.
EPS is produced in a three stage process:
Pre-expansion
Upon contact with steam the pre-foaming agent found within the polystyrene beads (usually a hydrocarbon such as pentane) starts to boil and the beads are expanded to between 40 to 50 times their original volume.
Conditioning
After expansion the beads undergo a maturing period in order to reach an equilibrium temperature and pressure.
Moulding
The beads are placed within a mould and again reheated with steam. The pre-foamed beads expand further, completely fill the mould cavity and fuse together. The beads are moulded to form blocks or customised products. When moulded, nearly all the volume of the EPS (~98%) is air.
There are two moulding processes for EPS:
Expanded Polystyrene is completely recyclable.
How is EPS recycled?
Segregation
EPS scrap must be segregated from other materials in the waste stream before it can be recycled. Ideally the EPS should be separated before it enters the waste stream to minimise contamination and so as to not take up bin capacity for other recyclable materials.
Collection
Since EPS is lightweight, transportation cost is a major component of its recycling. The material handling requirements for EPS scrap are usually determined by the recycler. Most commonly EPS scrap is either bagged in loose form or baled prior to transport.
Reprocessing
The collected EPS is fed into a granulation machine. The granulated material is then fed to a hopper where it is stored before being compressed into continuous lengths. This compressed material is broken into lengths suitable for palletisation. Once palletised the material is ready for shipment.
Converting EPS into other products
Once exported, the EPS material is then shredded and then extruded to form General Purpose Polystyrene (GPPS) pellets. This can then be used as a feedstock for applications such as synthetic timber, cd and video casette cases, stationery products as well as plant pots and coathangers.
