Development History of Extruded Polystyrene (XPS) Boards
The evolution history of extruded polystyrene (XPS) boards records not only technological iterations of polymer foaming processes, but also industry progress driven by global building energy-saving concepts and environmental policies. The core manufacturing machines for XPS boards are PS foam extruders and complete foam sheet extrusion lines.
The production of XPS boards heavily relies on foaming agents, whose technical evolution is profoundly affected by global environmental treaties. Early XPS production adopted chlorofluorocarbons (CFCs, commonly known as Freon) as physical foaming agents. Though featuring excellent thermal insulation performance, CFCs severely damage the ozone layer. After the signing of the Montreal Protocol in 1987, CFCs were phased out worldwide, and the whole industry shifted to transitional hydrochlorofluorocarbons (HCFCs, such as HCFC-142b and HCFC-22).
Entering the 21st century, global manufacturers jointly tackled supercritical CO₂ foaming equipment technology to eliminate ozone depletion potential (ODP) and lower global warming potential (GWP). Foshan Gaoming Keli Machinery Co., Ltd. has long focused on this green foaming technical route, jointly establishing the fourth-generation eco-friendly foaming system dominated by carbon dioxide and ethanol. This technology has been widely applied to various thermal insulation board extrusion lines.
In 1996, China introduced production line technology from Germany BASF and built the country’s first industrial demonstration XPS production line in China, marking the official industrialization of rigid thermal insulation materials in China. Around 2000, domestic plastic machinery manufacturers independently broke through core twin-screw extrusion technologies and ended foreign brand monopolies. Localized equipment brought explosive capacity growth and sharp cost cuts. Coinciding with China’s real estate and urbanization boom, XPS boards were widely adopted in construction projects nationwide. The first national standard GB/T 10801.2-2002 was released in 2002 to standardize the unregulated early market.
From 2009 to 2011, multiple severe fire accidents triggered by exterior wall thermal insulation materials pushed China to tighten building fire safety codes. Mandatory standards including GB 8624-2012 were issued to completely eliminate highly flammable Class B3 low-grade boards and upgrade the whole industry to flame-retardant Class B1 and Class B2 products.
Following China’s carbon peaking and carbon neutrality strategy and the implementation of Technical Standard for Near-Zero Energy Buildings, stricter requirements were raised for XPS thermal conductivity and environmental indicators. The revised national standard GB/T 10801.2-2023 was issued in December 2023 and enforced on July 1, 2024. Aligned with international high standards, the updated standard imposes strict limits on TVOC emissions and improves long-term thermal resistance and weather resistance, guiding China’s XPS industry toward green, low-carbon and long-life high-quality development.
