1) The rigidity of polypropylene (PP) is better than that of polyethylene (PE). The bending modulus of PP is about 1.52Gpa, while that of PE is only 207Mpa, and its chemical resistance is similar to that of PE.
2) The glass transition temperature of polypropylene is lower than room temperature, and its impact resistance is better than PS. Moreover, compared with PS foam, polypropylene foam is an environmentally friendly material.
3) Polypropylene has a high thermal deformation temperature and can be used in some high-temperature fields. Foamed polypropylene can usually withstand the high temperature of 130℃, which is much higher than the maximum service temperature of polyethylene foam of 80℃. The closed-cell structure makes its thermal conductivity unaffected by moisture, so it can be used as thermal insulation material.
4) Good low temperature characteristics: Even at -30℃, the product shows good performance.
5) Energy absorption: PP foamed products have good energy absorption characteristics and excellent compression energy absorption performance. Widely used in automobile bumper energy processing system and other anti-collision energy-absorbing components.
6) dimensional and shape recovery stability: PP foamed products will quickly recover to the original state after repeated continuous impact and bending deformation, and will not be permanently deformed.
7) light weight and reusability: the density of PP foamed products can reach a very low level, so the weight can be greatly reduced. At the same time, PP foamed products are flexible, reusable and not easy to break; Easy to recycle and decompose, the product does not contain toxic and harmful components to human body, and the combustion does not produce toxic substances.
8) Good surface protection and sound insulation performance: PP foamed products are semi-hard, moderate in hardness, and will not scratch or scratch objects in contact with them, so they have good surface protection.
Polypropylene resin has the characteristics of light weight, rich raw materials, excellent cost performance, excellent heat resistance and chemical corrosion resistance, and easy recycling. It is the fastest growing general thermoplastic resin in the world. At present, PP resin has become the largest resin variety in China. However, the applications are mainly woven products and agricultural films, and the PP resin industry faces the problems of single consumption structure, low demand and low product grade. All resin production enterprises are actively adjusting their production ideas and developing and producing marketable, high-quality and high-value-added special materials, so that PP has greater application value and economic benefits. Among them, the research and development of polypropylene foam has also become a hot spot in recent years. Although polypropylene foam products have good properties and application prospects, the development of polypropylene foam is very difficult, and there is no related and industrialized core technology in China at present. At present, some developed countries are vigorously developing it as a green packaging material to replace expanded polystyrene.
At present, EPP foaming particles are mostly realized by intermittent foaming. Due to the complex production process, high cost and high price, the price of EPP products in the domestic market is about 6.5438+0.2 million RMB/ton, while the price of EPP products in the European market is about 20,000 Euro/ton. The forming process of EPP parts is similar to that of EPS (mature process). Although the price is so high, the market of EPP is gradually expanding. Last year (fiscal year 2005), Japan Jesby Plastic Company produced and sold 65,438+10,000 tons of EPP foamed particles and molded products, which were mainly used as automobile bumper core materials. In China, JSP established an EPP pellet production base with an annual output of 3,000 tons in Wuxi in 2003, and completed the expansion of Phase II and Phase III projects. With the continuous expansion of EPP market demand in China, JSP plans to build a new EPP production base in Dongguan. Domestic manufacturers of foamed polypropylene products, such as Shanghai Zhongtong Auto Parts Co., Ltd., Shanghai One-to-One Insulation Products Co., Ltd., Foshan Nanhai Ocean Packaging Material Factory, Tianjin Runsheng Packaging Material Co., Ltd., etc., all use externally purchased polypropylene pre-foamed particles to produce packaging of auto parts and industrial products through the secondary foaming molding process, which is mostly used in the high-end product market.