Dry-free PET supercritical carbon dioxide foaming line
● In April 2019, “Dry-free PET reactive extrusion foaming integrated molding technology” passed the expert identification organized by China Light Industry Assication.
● The appraisal committee is composed of professors and industry experts from key national universities such as Tsinghua University, Fudan University and Zhejiang University. The director is Academician Qu Jinping of Chinese Academy of Engineering.
● The PET continuous extrusion foaming integrated process technology is innovative and advanced. The overall technology of the project has reached the international advanced level, and some technologies have reached the international advanced level.
Compared with other types of foam plastics, PET foam materials have their unique advantages:
1. PET foam has good dimensional stability, good sound insulation and heat insulation properties. Its short-time maximum working temperature can reach 200℃, and it can be used for a long time at 120℃, which is much higher than polyethylene (PE), polypropylene (PP), polystyrene (PS), polyurethane (PU), and vinyl chloride (PVC).
2. PET foam has excellent mechanical properties and fatigue resistance, better than PS, PU foam and glass foam.
3. PET foam has excellent FST (flame retardant, low smoke, non-toxic) performance.
4. PET foam has excellent wear resistance and surface blocking properties, and has good barrier properties to water vapor, oxygen (O2) and carbon dioxide (CO2).
5. The thermal expansion coefficient of PET foam is close to that of concrete and steel, and its thermal expansion performance is comparable to glass foam.
6. The water absorption of PET foam is lower than that of PS and PU foam.
7. PET can be recycled and reused and has little impact on the environment. Waste PET plastic is an important source of raw materials for the PET foaming process, and has greater advantages in terms of economic costs and environmental protection.
Co-rotating twin screw extruder + ultra-high vacuum unit + inert gas filler → Melt pump → Single screw extruder
Continuous extrusion foaming PET drying-free technology does not require pre-crystallization and drying of raw materials, which can significantly improve equipment production efficiency, reduce energy consumption and equipment investment. In addition, the supercritical carbon dioxide composite foaming system can also realize a completely incombustible foaming agent system, which greatly improves the process safety, significantly reduces the cell size, improves the cell uniformity, and finally improves the comprehensive mechanical properties of the PET foam material.
In addition, the optimized reaction chain extension system used in this equipment can adjust the viscoelasticity of the melt, making it easier to control the foaming process and control performance. The design of the foaming die head can realize the adjustment of porous strips, thin plates, thick plates and sheets, multi-process molding, and strong process flexibility.
Energy saving and environmental protection are also a highlight of this equipment. This set of equipment can not only use conventional flake-grade PET resin as the foaming matrix resin, but also use recycled PET flakes as the main resin, and the corner waste can also be completely recycled, so it is energy-saving, efficient, safe, environment friendly, and cost-effective to realize the stable and continuous extrusion production of PET boards and sheets with high foaming ratio.
PET foam materials are widely used in structural core materials, food packaging, sports equipment, microelectronics and other fields. The composite structure material of low-density PET foam core material, with its huge advantage of maintaining high strength and rigidity without increasing the weight of the product, has a very broad field in the fields of wind power, transportation, ships, and even aerospace etc.
The emergence of "drying-free PET reactive extrusion foaming integrated molding unit", whether it is to enrich the structure of polyester industrial products, expand the application of PET, or promote the development of high-performance foaming material preparation technology and application fields, is very important.