Thread Content
TPU (Thermoplastic Polyurethane Elastomer) is an emerging type of plastic. Thanks to its good processability, weather resistance, and environmental friendliness, TPU is widely used in industries such as manufacturing, plastic films, the automotive sector, wires and cables, adhesives, healthcare, footwear, toys, apparel, pipes, rollers, and aviation. Polyurethane thermoplastic elastomers, also known as thermoplastic polyurethane rubbers and abbreviated as TPU, are type (AB)n block-linear polymers. Component A is a high-molecular-weight (1000–6000) polyester or polyether, while component B is a diol containing 2–12 straight-chain carbon atoms. The chemical structure between the AB segments is connected by diisocyanate, usually MDI. The general structural formula is shown in the figure. Thermoplastic polyurethane rubber is cross-linked through intermolecular hydrogen bonds or mild cross-linking between macromolecular chains, and these two types of cross-linking structures are reversible as the temperature rises or falls. In the molten or solution state, intermolecular forces are weakened; however, after cooling or solvent evaporation, strong intermolecular forces bring them together again, restoring the properties of the original solid. Polyurethane thermoplastic elastomers come in two types: polyester-type and polyether-type. They appear as white, irregular spherical or cylindrical particles, with a relative density of 1.10–1.25; the polyether-type has a lower relative density than the polyester-type. The glass transition temperature of the polyether type is 100.6–106.1°C, while that of the polyester type is 108.9–122.8°C. The brittle temperature of polyether and polyester types is below -62°C, and the low-temperature resistance of hard ether types is inferior to that of polyester types. Polyurethane thermoplastic elastomers are distinguished by their excellent wear resistance, outstanding ozone resistance, high hardness, high strength, good elasticity, and low-temperature tolerance. They also possess good oil resistance, chemical resistance, and environmental resistance; in humid environments, the hydrolytic stability of polyether-type ones far exceeds that of polyester-type ones. Polyurethane thermoplastic elastomers are non-toxic and odorless. They are soluble in solvents such as toluene, ethyl acetate, xylene, and dimethylformamide, as well as in mixed solvents composed of these substances in appropriate proportions. They appear colorless and transparent, and possess good storage stability. Domestic TPU developments ● In March 2009, Shandong Hongye Chemical began to enter the TPU sector, which meant that another new TPU-grade product was added to the domestic adipic acid industry. According to the company’s relevant officials, at present, it is mainly Taiwanese-funded enterprises that cooperate with the company; these enterprises have shifted from importing TPU-grade adipic acid to using the products produced by Hongye, and the response has been positive. ●In June 2009, an interview with a responsible official from Zhonglu Borun Special Chemicals Manufacturing (Shanghai) Co., Ltd. revealed that the company’s new 4,000-ton/year thermoplastic polyurethane elastomer (TPU) production facility was under construction, with completion of this TPU plant expected by the end of 2009. At present, Lubrizol Special Chemicals Manufacturing (Shanghai) Co., Ltd. has a production facility with a capacity of 10,000 tons of TPU per year. ●In July 2009, at the first Wenzhou Resin Forum, representatives from Liaoyang Petrochemical said in response to questions that the company was willing to cooperate with downstream enterprises to develop TPU-grade adipic acid products. She explained that earlier, Liaoyang Petrochemical had collaborated with Huafeng Spandex on a project related to TPU-grade adipic acid, but it was halted for various reasons later on. Although Liaoyang Petrochemical currently has no specific plans to produce this product, it remains willing to engage in collaborative development as long as downstream companies are interested. ●In October 2009, according to informed sources, the investment project of Shanghai Beigang Polymer Technology Co., Ltd., which involves an investment of 12 million yuan for a plant capable of producing 4,000 tons of TPU per year, is currently in the preliminary testing phase. Earlier, in July, it was reported that the project was under the second round of public consultation regarding its environmental impact assessment. ●In October 2009, according to people familiar with the matter, a company in Ningbo intended to set up a production line capable of producing around 5,000 tons of TPU per year; currently, this project is still in the initial testing phase.