How to make EPS foam

Kai Hendry, Creative Commons License

EPS foam is a highly durable material that is used in a large number of consumer products. EPS stands for Expandable Polystyrene. This expanding foam compound is an excellent insulating material. It is used in refrigerators, coolers, helmets and many other products that are used every day. The large number of uses for EPS foam creates a high demand that makes this a very profitable business to be part of. If you have a manufacturing background, it is entirely possible to make EPS foam products yourself.

Impregnate the polystyrene resin granules with the blowing agent. When making EPS foam, Pentane Gas (C5H12) is normally used as the blowing agent. A small amount of pentane gas is injected into the resin in a process known as Polymerization.

Begin the pre-expansion process. After the resin granules have been impregnated, place them into your steamer and use steam to heat the granules. The heat will cause a reaction with the granules and the blowing agent, and will cause the polystyrene granules to expand to 50 times their original size. At this stage you have a large number of individual foam pellets that are ready to be moulded.

Decide on what method of moulding your will use on your EPS foam. There are two standard options for moulding. The first method is to use a "shape molding" machine. This method will mould your foam to the precise size and shape of the product being developed. The second option is to use a "block molding" machine. Doing block moulding creates large blocks or even sheets of EPS foam, which can later be cut to the size and shape that the customer requires. It is important to decide which method applies to the EPS foam you will make, so that you can choose an appropriate moulding machine.

Pour the EPS granules into your mould and complete a second heating. The second time the granules are heated with steam, they will swell within the mould and become pressed together into one solid piece of foam. It is this mould heating process that transforms them from individual grains to a sheet of EPS foam.

Remove the EPS foam product from the mould and allow it to cool. The cooling time will depend on how large your foam item is. Allow the foam to sit and cool until it has reached room temperature. Inspect the mould for any cracks or damage before approving it for use.

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