XPE foam safety

Is XPE foam safe? The material itself carries no hazardous additives, and the safety questions that do come up — fire behaviour, residue, what it releases indoors — each have a specific answer. This page sets out the process behind the material and then takes those questions in turn.

XPE foam is cross-linked polyethylene: a closed-cell sheet made from polyethylene with a peroxide cross-linking agent. The cross-links lock the polymer into a three-dimensional network, and that network is what holds the sheet’s dimensions under heat and resists tearing when it is pulled.

Manufacturing process

The production of XPE foam has five steps:

1. Polyethylene is compounded with a peroxide cross-linking agent and a chemical blowing agent.
2. The compound is formed into sheet at the required thickness.
3. The sheet is heated, the peroxide decomposes, and the polyethylene molecules are cross-linked into a network.
4. At a higher temperature the blowing agent decomposes and releases gas, expanding the cross-linked sheet into a foam.
5. The foam is cooled and the cell structure is fixed.

Scope of application

XPE foam is used in the following areas:

1. Packaging and protective inserts
2. Sports equipment, including yoga mats and protective padding
3. Building and underfloor insulation
4. Automotive interior trim
5. Medical supplies
6. Cushioning for electronic equipment

Safety performance features

1. Fire retardant. XPE foam can be supplied in flame-retardant grades that resist the spread of flame, and low-smoke grades are also available. Many XPE foam products meet international standards, such as UL94 V2, which means they do not easily ignite, and that if they do burn they self-extinguish.
2. RoHS and REACH documentation. XPE foam can be supplied to support compliance with the EU RoHS directive and REACH; test reports for a specific grade are available on request.
3. Chemical resistance. XPE foam resists a wide range of chemicals, including acids, alkalis and organic solvents, which suits it to laboratories, chemical plants and other environments where contact with chemicals is expected.
4. Antimicrobial and anti-mould. The surface does not support the growth of bacteria or mould, which is why the material is used in medical supplies and sanitary facilities, and why it helps keep those products clean and lowers the risk of infection.
5. Shock absorption. XPE foam absorbs impact energy and returns to shape. That is the property that protects packaged goods and sports equipment, and that damps vibration around vehicle interiors.
6. Low VOCs. XPE foam releases few volatile organic compounds, so fewer harmful substances reach the air and it is safe to specify indoors.
7. Temperature resistance. The material keeps its properties across a wide working range, from low to high temperatures, which suits it to a variety of climates. Where service temperature is the binding constraint, heat-resistant functional grades are rated for a 110 °C environment with shrinkage of 8% or less.

Conclusion

What makes XPE foam safe is not one property but the same one appearing several times: the closed-cell cross-linked structure. It is what stops flame spreading through the sheet, what keeps liquids and chemicals out of the core, what holds shape under heat, and what absorbs impact. Specify the grade that matches the risk in front of you — flame-retardant or low-smoke for fire, heat-resistant for high temperature, conductive for static control — and the safety case follows from the data sheet rather than from the description.

References

• [1] ISO 9001:2015 Quality Management Systems - Requirements
• [2] UL 94 Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances
• [3] RoHS Directive 2011/65/EU on the restriction of the use of certain hazardous substances in electrical and electronic equipment
• [4] ASTM D3574 Test Methods for Flexible Cellular Materials-Slab, Bonded, and Molded Urethane Foams

See XPE foam for material data, or contact us for safety documentation.