Supercritical CO₂ Physical Foaming vs. Conventional Chemical Foaming — Process Differences & Equipment Selection
The foamed materials industry currently relies on two mainstream forming routes: chemical foaming and physical foaming. Chemical foaming generates pores through gas released by decomposing chemical blowing agents. It features low equipment thresholds and low initial capital investment, but finished products suffer blowing-agent residues, uneven cell sizes and insufficient environmental performance. Supercritical CO₂ physical foaming uses carbon dioxide as the blowing medium, leaving no chemical residues and producing fine, uniform cells. It has become the mainstream mass-production solution for high-end PET structural foam, with the PET Foamed Board Extruder as the core equipment.
The most intuitive difference between the two processes lies in finished-product performance. Chemically foamed sheets typically feature cell diameters in the hundreds of microns with a broad size distribution and fluctuating mechanical properties. The PET CO₂ Foamed Board Extruder, through a decoupled design of low-temperature high-pressure saturation in the first stage and slow foaming with back pressure in the second stage, stabilizes cell size below 50 microns. Compressive strength and fatigue resistance are significantly improved, making the material suitable for high-end applications such as wind-power core materials and new-energy-battery insulation panels.
Environmental compliance is another key distinction. Decomposition of chemical blowing agents generates by-product residues, and certain categories involve VOC emissions, easily creating compliance barriers for exports to the EU and North America. The supercritical CO₂ process uses inert gas as the medium, leaving no residues in finished products and generating no pollution during production, fully aligning with global dual-carbon policies. Matched with a PET Foam Sheet Extrusion Line, it realizes full automation from raw-material drying, extrusion and foaming to cutting, delivering stronger mass-production stability.
Regarding equipment selection, small and medium manufacturers focusing on ordinary packaging cushioning materials can retain conventional chemical-foaming lines. For target customers in wind power, new energy and high-end cold chain, where material performance requirements are stringent, it is recommended to directly configure a PET CO₂ Foamed Board Extruder paired with a complete PET Foam Sheet Extrusion Line, meeting high-end market demand in one step and avoiding repeated retrofitting investment later.
