Expanded Polystyrene Foam or EPS foam
Get to know each other.Expanded Polystyrene Foam (EPS) Expanded Polystyrene Foam (EPS) is a material created by bonding closed-cell foam beads together using steam heat. It consists of 98% air and only 2% polystyrene (PS) plastic. The bonding of the foam beads provides support and distributes the force applied to the workpiece. Therefore, despite its lightweight nature, Expanded Polystyrene Foam maintains its shape well, possesses excellent load-bearing and thermal insulation properties. These outstanding physical characteristics and properties make it popular for manufacturing in a wide variety of applications, including foam beads, foam sheets, foam blocks, packaging foam, molded foam, shock-absorbing foam, and even construction foam.
- EPS foam (eps foam) is PS foam Using pentane gas (C5H12It expands when heated by steam, becoming white foam beads. These beads can then be molded in two ways: compressed into shapes according to a mold, or compressed into rectangular blocks.Foam block It is then processed and cut into foam sheets of the desired thickness.
- PSP foam This refers to PS plastic pellets that have been passed through a heated screw. While the plastic pellets are melting, they release Butane gas (C₂).4H10(The process continues) until the polystyrene expands approximately 20 times its original size. It is then injected into sheets, stored in rolls like paper, and finally molded into boxes or food trays.
Additional information
https://omnexus.specialchem.com/selection-guide/expanded-polystyrene-eps-foam-insulation
What is the manufacturing process of foam?
1. Expanded Polystyrene Foam (EPS) It involves the use of pentane gas (C).5H12) , which belongs to the same family as liquefied petroleum gas (LPG), is an expanding agent (blowing agent) added during the polymerization process of the raw material pellets. The polystyrene (PS) plastic material retains pentane gas within the pellets. These pellets are then used to produce expanded polystyrene foam by heating them with steam until they expand into white foam beads. These foam beads are then molded in a mold using steam again. The foam beads fuse together to form a block or shape according to the mold, ready for further processing or use as needed. Molding has two forms: 1.1 Shape molding: Molding into various shapes according to the mold design, such as ice boxes and various packaging. 1.2 Block molding: Molding into rectangular blocks and then cutting to the desired size and shape. Generally, EPS foam expands approximately 50 times its original size. Then, air replaces up to 98% of the volume, leaving only 2% as PS plastic material. This is why the foam is large in size but lightweight. This characteristic is what makes EPS foam excellent at absorbing impact, making it suitable for packaging goods. It also supports vertical weight without deformation, making it used as a fill material in road construction to solve the problem of road subsidence. Furthermore, it serves as thermal insulation because the 98% air inside acts as a good insulator.
Why doesn't foam contain CFCs?
Both EPS and PSP foam consist of 95-98% air, with the remaining 2-5% being polystyrene plastic, which is a hydrocarbon compound called CFCs (Chlorofluorocarbons). CFCs are compounds of chlorine, fluorine, and carbon, and their composition differs from the polystyrene that makes up the foam. Because CFCs have a low volatile point, they are difficult to retain in the raw materials. Therefore, EPS foam has never used CFCs in its manufacturing process since BASF of Germany first produced EPS foam in 1952. The substance used to expand EPS foam is pentane gas, which does not contain chlorine.
Initially, PSP foam used CFCs, but as CFC usage was reduced in both the plastics and refrigeration industries over the past two decades, PSP foam manufacturers switched to butane gas approximately 15 years ago. Butane is the same gas used in household cooking today. Therefore, nowadays, the expanding agents in foam are pentane and LPG. Both of these gases are hydrocarbon compounds, just like polystyrene plastic. They belong to the same family as the widely known methane, ethane, and propane.
What are some possible uses for used foam?
In addition to being recycled, used EPS foam can be managed in the following ways:
- Mix the crushed EPS foam with the soil for planting, as it helps to loosen the soil and the air inside will benefit the plant roots.
- EPS foam is used in concrete mixing for construction because it has insulating properties and is lightweight. Incorporating crushed EPS foam into concrete reduces the weight of the material and also helps maintain the temperature of the construction site.Burning EPS foam for fuel is possible because EPS foam contains mostly air. When burned at high temperatures, around 1000 degrees Celsius, the crushed foam is incinerated without producing environmentally harmful substances and without the need for any additional fuel. One kilogram of EPS foam burned using this process can yield energy equivalent to 1.2-1.4 liters of oil.
Foam recycling
Because both EPS and PSP foam are made of polystyrene, a thermoplastic, they can be recycled back into polystyrene.
The recycling process for both types of foam begins with crushing the foam scraps into smaller pieces. The crushed foam is then either melted or compressed. Melting is done using a heated screw (screw extrusion) at a temperature above the melting point. Compression is done using an agglomeration system with blades, heated by pressure and friction, at a temperature below the plastic's melting point.
Recycled PS plastic from foam can be used to produce common plastic products such as cassette tapes, video tapes, rulers, pencil cases, and coasters. Furthermore, shredded EPS foam scraps can be mixed with new foam beads and used to manufacture foam again.
Conditions for recycling PS foam.
Recycling PS foam in Thailand is similar to that of general plastic recycling. Both EPS and PSP foam manufacturers have the capacity to reuse it in their production processes to a certain extent, in order to reduce raw material costs and manage production waste. The average waste rate for EPS foam production is no more than 5%, equivalent to approximately 125 tons of waste per month. The average waste rate for PSP foam production is no more than 20% (due to differences in production processes), equivalent to approximately 300 tons of waste per month.
In addition to recycling by the foam manufacturers themselves, there are also buyers who purchase waste from foam manufacturing plants to recycle into low-grade PS plastic.
In the past, recycling of PS foam collected from the public was insufficient due to a lack of public knowledge and understanding about PS foam. This led to negative attitudes, particularly regarding foam recycling, with many believing that foam could not be recycled, which is untrue. Furthermore, the process of collecting EPS foam, which is often large but lightweight, results in higher transportation costs compared to other types of plastic.
However, the group is currently working to disseminate factual information and correct understanding. In addition, they are developing a foam compression machine to reduce the size and weight of stored foam, thereby lowering transportation costs from various locations to recycling plants. This will help increase the amount of foam collected for recycling continuously.
PS foam industry in Thailand
The PS foam industry in Thailand was established approximately... 50 For many years, the production of EPS foam began with block molding for use in cold storage panels. As domestic industry grew, the use of EPS foam for packaging, particularly electrical appliances and electronics for export, began around 1977. Later, EPS foam was also used in construction for buildings, bridges, and roads. Currently, there are 5 domestic EPS raw material producers and approximately 25 EPS foam producers. Most producers are located in Bangkok and its surrounding areas, with a total production capacity of approximately 2,800–3,000 tons per month. The majority of EPS foam produced is used as packaging for electrical appliances and electronics for export. In addition, POLYGLOSS 2, made from EPS foam, is also used for packaging frozen seafood for export. As for PSP foam, it started about 15 years ago with 5 domestic raw material producers (PS plastic pellets) and 10 PSP foam producers, only one of whom is not located in Bangkok. The total production capacity is… Currently, approximately 1300-1500 tons per month of PSP foam are produced, primarily for food trays and boxes, with about 30% of the production going into export.
