Cross-linked polyethylene foam, commonly known as IXPE (electron-beam cross-linked polyethylene foam), is a high-performance closed-cell polymeric foam material. Manufactured through advanced physical cross-linking and foaming technology, it differs fundamentally from chemically cross-linked XPE foam and conventional EVA foam. With a uniform microcellular structure, stable physical properties, excellent environmental adaptability and superior processing performance, IXPE foam has gradually replaced traditional foam materials and become a core lightweight material widely used in electronics, automotive manufacturing, household appliances, packaging and new energy industries.
1. Production Principle of IXPE Foam
The production of IXPE foam adopts a green physical irradiation cross-linking process, which is completely different from the chemical cross-linking mechanism of XPE and EVA foam. The whole production process is divided into four core stages with no chemical residue and high safety.
First, raw material extrusion and sheet forming. Low-density polyethylene (LDPE) resin is used as the base material, mixed with environmentally friendly auxiliary agents and physical blowing agents. The mixture is uniformly melted and extruded into flat sheets through a precision extruder, laying a uniform foundation for subsequent cross-linking and foaming.
Second, electron-beam irradiation cross-linking is the core and most critical step of IXPE production. The extruded PE sheet is irradiated by high-energy electron beams generated by an electron accelerator. The high-energy radiation breaks part of the polyethylene molecular chains and induces free radical polymerization, forming a dense and stable three-dimensional network cross-linking structure between molecular chains. This physical cross-linking method does not require peroxide chemical cross-linking agents, avoiding residual chemical substances.
Third, high-temperature continuous foaming. The cross-linked sheet is sent to a high-temperature foaming furnace. Under precise temperature control, the physical blowing agent inside the sheet expands stably. Restricted by the three-dimensional network skeleton formed by cross-linking, bubbles expand evenly to form independent closed-cell structures with consistent pore size. The cell size of finished IXPE foam is concentrated at 80–300 μm, with extremely high uniformity.
Fourth, cooling, shaping and slitting. The foamed foam is rapidly cooled and shaped to fix the microcellular structure, then cut into standard sheets or rolls according to application requirements, completing the finished product processing.

2. Comparative Advantages: IXPE vs XPE Foam vs EVA Foam
In industrial applications, EVA foam, chemically cross-linked XPE foam and physically cross-linked IXPE foam are the three mainstream foam materials. IXPE shows comprehensive performance advantages in structure, stability, durability and environmental protection.
2.1 IXPE vs Chemically Cross-Linked XPE Foam
XPE foam relies on peroxide chemical agents to complete cross-linking during high-temperature foaming. In contrast, IXPE adopts physical electron-beam cross-linking, bringing obvious upgrades.
First, more uniform cell structure. IXPE’s irradiation cross-linking forms an integral network structure in advance, so the bubble expansion force is balanced. Its cell distribution uniformity is far better than XPE, with a smooth and velvety surface without bulges or pits. XPE’s chemical cross-linking reaction is unstable, resulting in uneven pore size and rough surface.
Second, higher dimensional stability. The three-dimensional network of IXPE is tighter and more stable, with a linear shrinkage rate lower than 1.2%, which resists deformation during high-temperature processing and long-term use. XPE is prone to shrinkage and warping after heating.
Third, better safety and durability. IXPE has no chemical cross-linking agent residue, while XPE may have residual peroxide substances, leading to aging, yellowing and performance attenuation after long-term use.
2.2 IXPE vs Traditional EVA Foam
EVA foam is a traditional thermoplastic foam with low production cost but obvious performance defects compared with IXPE.
First, superior water and moisture resistance. IXPE is a fully closed-cell structure with zero water absorption and excellent waterproof and moisture-proof properties. EVA foam has partial open-cell structures, which easily absorb water and mildew in humid environments.
Second, excellent temperature resistance and weather resistance. IXPE can maintain stable elasticity and mechanical properties in the temperature range of -40°C to 80°C, resisting ultraviolet aging. EVA foam is prone to hardening at low temperatures and softening and aging at high temperatures.
Third, better resilience and shock absorption. IXPE has uniform and delicate cells, providing soft and lasting cushioning resilience without permanent compression deformation. EVA foam has poor resilience and is easy to collapse after long-term compression.
Fourth, environmental protection and recyclability. IXPE is free of harmful additives, odorless and compliant with global environmental protection standards. Traditional EVA production uses chemical foaming agents, with slight odor and limited environmental compliance.
3. Development Prospects of IXPE Foam Industry
With the upgrading of global lightweight manufacturing, environmental protection policies and high-end industrial manufacturing, IXPE foam, as a high-end new material, has broad market development space and huge growth potential.
First, continuous expansion of downstream high-end application markets. In the consumer electronics industry, IXPE is widely used in mobile phone buffer layers, screen shock-absorbing materials and thermal insulation gaskets due to its ultra-thin, uniform and dust-free characteristics. In the new energy industry, it serves as battery thermal insulation, shock absorption and flame-retardant buffer material for new energy vehicles, becoming an indispensable safety material for power batteries. In automotive lightweighting, IXPE replaces heavy rubber and traditional foam materials for interior sound insulation, shock absorption and thermal insulation, effectively reducing vehicle weight.
Second, strict global environmental policies drive material replacement. Traditional EVA and XPE foams have residual chemical substances and poor environmental performance, which are gradually restricted by EU GPSR, REACH and other environmental regulations. IXPE’s physical cross-linking production process is pollution-free, residue-free and odorless, fully meeting the high environmental protection standards of European and American markets, and has become the preferred export foam material.
Third, process iteration promotes performance upgrading and cost optimization. With the popularization of electron-beam irradiation equipment and continuous optimization of foaming technology, the production cost of IXPE is gradually reduced. At the same time, modified IXPE products with flame retardant, anti-static, high thermal insulation and antibacterial functions continue to emerge, expanding its application boundaries from traditional civil use to high-end industrial, medical and aerospace fields.
Fourth, market demand maintains steady growth. Benefiting from the booming development of new energy vehicles, smart home appliances, high-end packaging and outdoor sports industries, the global demand for high-performance foam materials is rising year by year. IXPE, with its comprehensive performance advantages, will continuously erode the market share of low-end EVA and XPE foam materials, showing a long-term upward development trend.
Conclusion
IXPE cross-linked polyethylene foam achieves a more stable and delicate microcellular structure through advanced physical irradiation cross-linking and physical foaming technology. Compared with traditional XPE and EVA foam materials, it has unparalleled advantages in dimensional stability, weather resistance, shock absorption, environmental safety and processing performance. Driven by industrial upgrading and global environmental protection trends, IXPE foam will continue to expand its application scenarios, realize high-end and diversified development, and become one of the most promising lightweight new polymer materials in the future industrial manufacturing field.