Views: 49 Author: Site Editor Publish Time: 2025-06-24 Origin: Site
I. Analysis of the Supercritical Foaming Injection Process
Supercritical foaming is a physical foaming technology that utilizes supercritical fluids such as carbon dioxide or nitrogen as blowing agents. Under high-temperature and high-pressure conditions, the gas enters the polymer matrix, and then rapid pressure relief causes the gas to expand, forming a uniform microporous structure.
This process is environmentally friendly, odorless, and non-toxic, providing long-term protection for both consumers and producers. Without the use of cross-linking agents, the materials can be melt-recycled, making it one of the most popular processes in the shoe material field. Additionally, supercritical foaming also shows great market growth potential in industries such as automotive, toys, and protection.
In terms of shoe midsole technology, there are currently four processes for supercritical foaming, corresponding to different development times and maturity levels: bead foaming, sheet foaming, small-to-large foaming, and direct injection molding.
Among them, supercritical injection foaming, also known as injection molding foaming, involves directly injecting the supercritical fluid into the injection molding machine to integrate foaming and molding.
Process: During the melting of TPU in the injection molding machine, supercritical CO₂ or N₂ is injected into the melt to form a uniform single-phase mixed solution. After injecting the solution into the mold, foaming occurs through rapid pressure relief, resulting in a foamed part with a specific shape.
Supercritical injection foaming is suitable for products with complex shapes, combining lightweight properties with mechanical performance. However, it requires high-end equipment, including high-pressure-resistant injection molding machines and precise temperature control systems, and the cost of continuous extrusion-injection integrated equipment is also relatively high.
II. Manufacturers of Supercritical Foaming Injection Molding Equipment for Shoe Materials
Currently, the supercritical foaming injection molding machines for shoe materials are mainly produced by German and Taiwanese enterprises and have not yet been applied in mainland China. Some international brands have set up production lines in Vietnam and South Korea. Overall, the process debugging is still not mature enough, and further optimization is needed in aspects such as material formulation, mold design, and precise temperature control. The following is a summary of the manufacturers of supercritical foaming injection molding machines for shoe materials.
1. DESMA
DESMA, a German company, provides the highest-quality, most efficient, and most economical shoe machine production systems, reliably and quickly supplying shoe manufacturers around the world.
DESMA's Supercritical Foaming Injection Molding Technology® uses an integrated molding process, different from traditional supercritical foaming technologies such as small-to-large foaming. This technology can complete product production through a single feeding and foaming injection, eliminating the need for secondary processing.
Compared with the traditional autoclave impregnation process, the advantages of supercritical foaming injection molding technology are that the energy consumption is only 1/10 of that of the autoclave impregnation process, and the production efficiency is significantly improved. The equipment can produce 60 to 70 pairs of finished products per hour.
Reliable technology creates high-performance products. With scalable and flexible solutions, it can run up to 36 molds. The adjustable density range is 0.15 - 0.40 g/cm³.
2. KINGSTEEL
KINGSTEEL focuses on the research, development, and manufacturing of injection molding equipment for foamed elastomers and industrial elastomers. It closely cooperates with customers, using the MICS core technology to provide electromechanical integration services for "multi-injection systems and multi-mold production workstations" in a single device.
The NexCel supercritical fluid foamed elastomer injection molding machine jointly developed by KINGSTEEL and its European co-innovation partner (ECIP) is the world's first "mass-production type" supercritical fluid foamed elastomer injection molding machine.
This equipment is developed based on KINGSTEEL's decades of accumulated MICS™ core integration technology (Multiple Injectors and Mold-Clamp System, MICS™). It integrates supercritical fluid foamed elastomer injection molding with multiple injection guns, multiple workstations, and multiple molds into a single device, named "NexCell ® ".
3. TIENKANG
As a research and development technology manufacturer, TIENKANG focuses on the development of automated, energy-efficient, and environmentally friendly models, further enhancing customer benefits and achieving high production efficiency.
The global market demand for shoe soles and the carbon emissions during the production process have a significant impact on the global environment. The GENTREX system, a proprietary technology and technological advantage jointly developed by TIENKANG and the FCS team, uses the MuCell supercritical micro-foaming equipment from the American company Trexel to successfully mix liquid nitrogen (N₂) supercritical fluid into the molten thermoplastic elastomer.
4. Fujian Dongpu Technology Industry Co., Ltd.
Fujian Dongpu Technology Industry Co., Ltd. specializes in various types of shoe molding machines, such as fully automatic EVA single and double-color injection foaming molding machines, injection molding foaming machines with vacuum covers, vacuum cover vulcanization foaming machines, EVA shoe blank foaming molding machines, PVC single, double, and three-color injection blowing molding machines, PVC single, double, three, four, and five-color belt injection molding machines, PVC single and double-color insole injection molding machines, TR/TPU/PVC/TPR single and double-color injection molding machines, EVA small foaming and secondary foaming molding machines, rubber hydraulic molding machines, and various types of injection molding machines.
