About Closed-Cell Foam

Closed-Cell Polyolefin Foams

Polyolefin foams are solid (rather than liquid) foams that are manufactured from a variety of plastic compounds to which foaming agents have been added. During manufacture, the foaming agents cause bubbles of gas to form inside the foam. In open-celled foams, such as sponges or mattress foam, these bubbles (or cells) of air are open, allowing liquids and air to be freely taken up into the foam. In contrast, closed-cell foams have closed bubbles which do not allow air or liquids to be taken up, except on their cut surfaces. This allows the foams to have excellent insulative and cushioning properties. Other properties of the foam, such as its density, chemical composition, and additives determine the applications to which the foam is best suited. These foams are given additional strength by physical (UV) or chemical cross-linking of molecules. Cross-linked polyolefin foams are given the abbreviation “XLPO”.

There are two main methods of manufacture of closed-cell foams: by extrusion, which allows a continuous length of foam to be produced in thicknesses of up to 15 mm and 1800 mm width; or by block blowing, in which foam blocks of generally up to 50 mm thickness are blown in moulds of around 2000 mm X 1000 mm. This “block” foam tends to have a finer cell size and smoother surface, but is more easily marked or scratched than the extruded foam, and is provided in fixed-size sheets only (generally of 2000 mm X 1000 mm or so), rather than rolls.

Closed-cell polyolefin foams are used in a wide variety of applications requiring padding, floatation, insulation, space filling, cushioning, anti-vibration and noise dampening. Specific applications include aquatic accessories, such as rescue tubes, pool mats, spa covers, boat seats and fenders; industrial applications, such as gaskets and floatation devices; civil applications such as expansion joint and void fillers; automotive applications, such as auto-noise barrier and upholstery; case making applications, such as case inserts; medical applications, such as physiotherapy mats and radiography wedges; construction applications, such as pipe and air-conditioner duct insulation, and carpet and timber floor underlay, and sporting applications, such as martial arts mats and rodeo armour.

What We Import:

3H Foam imports and manufactures a variety of closed-cell foam products that are either extruded Trocellen® foams, sourced from our major supplier in Malaysia, or block foams sourced from a variety of Australian and overseas foam suppliers. They are supplied in black and white, and a range of colours. These products are on-sold in an unconverted form or converted in a number of ways from simply cutting or splitting to complete manufacture of final products, such as rescue tubes and kick boards.

Raw Materials:

Trocellen® foams:

Trocellen® foams supplied as rolls or sheets of up to 15mm thickness and 1800mm width. The foams are extruded (rather than foamed in blocks). These foams are physically (by UV) or chemically cross-linked to provide strength, and may be further modified by addition of fire retardants, adhesives, foil (for use as insulation) or lamination (to provide greater thickness). There are two main formulations: N-series, a plain polyethylene (PE) compound; and W3C, a PE/ Ethylene vinyl acetate (EVA) mixture that provides greater flexibility and a more “rubbery” surface. Both types of foam may be supplied in a range of densities from 25 kg/m3 (soft) to 200 kg/m3 (hard).

N series foams: extruded sheets of 8-15mm thickness polyethylene foam, supplied in rolls of approximately 25-50 m. A variety of densities are available from 25 kg/m3 to 180 kg/m3. These foams are general purpose foams for a wide variety of applications including insulation, cushioning, void-filling, and case-making.

W3C: extruded sheets of 8-15 mm thickness made from a special blend including PE and EVA polymers. This formulation has greater memory and flexibility, and is particularly useful for padding for seats and other upholstery applications, or any application requiring foam of good “memory”. It is also used for manufacture of our rescue tubes. Available in 25, 33, 45 and 70 kg/m3 densities.

WB: extruded sheets of 8-15 mm thickness made from a PE/EVA blend, similar to W3C, but with better memory and faster rebound properties. It is ideal for marine seating, upholstery and other applications requiring superior memory and a slightly more “rubbery” feel than W3C. Available in 25, 45 and 70 kg/m3 densities.

Block foam material

We supply two types of block foam material in a range of densities from 30 kg/m3 to 70 kg/m3: PE and EVA. These are supplied as sheets of around 2000 mm X 1000 mm in a range of thicknesses from 10 mm to 50 mm. They may also be split or laminated to give blocks or sheets of greater or lesser thickness. In comparison with the Trocellen® foam, the block foam material has a finer cell size and therefore a smoother cut surface, but the surface is more easily marked. PE is a good general purpose foam for any application not requiring good “memory”, whereas the EVA is a more flexible foam with greater memory for applications requiring repeated compression and release, such as padding for seating.