Overview of the development of domestic rotational molding industry with the development of science and technology

Overview of the development of domestic rotational molding industry with the development of science and technology

Research and development of rotomolding in my country began in the 1960s. At that time, the Shanghai toy industry began using rotomolding to produce soft polyvinyl chloride pellets. Shanghai Plastics Factory No. 3 successfully trial-produced rotomolded polyethylene containers with volumes of 200L and 1500L. In the mid-1970s, the Beijing Fiberglass Research Institute successfully developed rotomolded nylon containers, which were used in products such as forest fire extinguishers. By 1992, while dozens of rotomolding plants existed in my country, the vast majority employed equipment and technology from the 1950s and 1960s. Annual resin processing capacity was approximately 9,000 tons, representing only 8-90,000th of China's total resin consumption and 1% of the global average. The company produced approximately 28 different products, representing 0.5% of the global total. While some plastics companies have ventured into rotomolding, limitations in key processes have prevented them from achieving significant breakthroughs, resulting in products with limited dimensional requirements and relatively crude performance. Consequently, most practitioners have been unaware of the advanced nature and competitive advantages of rotomolding. In the words of a leading American rotomolder, "Rotational molding in China hasn't taken off yet, and the Chinese rotomolding market is untapped!"

In the mid-to-late 1990s, some domestic companies imported advanced rotomolding equipment and technology from abroad and began truly large-scale industrial production. Currently, domestic companies are capable of producing large plastic products, such as chemical storage tanks with a capacity of over 20,000 liters and high-speed, all-plastic yachts. In recent years, my country's rotomolding industry has developed rapidly, with nearly 100 rotomolding factories nationwide. These factories produce a growing variety of rotomolded products, with applications spanning an ever-expanding range. However, compared with the advanced levels of developed countries, there is still a significant gap. In the early 1990s, over 5,000 types of rotomolded products were registered with the American Rotomolding Association, while my country still only has a little over 40. Rotomolding products are used in over 30 industries abroad, while in my country, they are only used in a dozen or so. Regarding rotomolding raw materials, polyethylene and its composite materials currently account for approximately 75% of all rotomolded products in China. Over 99% of these products are made from PE, 95% of which is rotomolding-grade LLDPE, which is highly suitable for rotomolding. The proportion of polyethylene used in rotomolding abroad is roughly: LLDPE (65%), XHDPE (cross-linked polyethylene) (2%), HDPE (10%), and LDPE (5%).

To adapt to the growing variety of rotomolded products, their increasing technological content, and the increasing demand for rotomolded products across various industries, the China Plastics Processing Industry Association has established a Rotomolding Committee. This committee aims to exchange rotomolding process technology and experience, assimilate advanced international technology and equipment, strengthen technical collaboration, promote the development of rotomolding technology, processing equipment, and molds in my country, and research and develop specialized rotomolding materials and products.