The production of TPU series materials uses diisocyanates, polyols and chain extenders as core raw materials, and the core processes are prepolymerization reaction and chain growth reaction. Technological upgrading focuses on three directions: improving reaction efficiency, optimizing product performance, and realizing flexible production. In the prepolymerization stage, the traditional batch reaction has problems of uneven molecular weight distribution of prepolymers (dispersion index 2.5-3.0) and large performance fluctuations between batches. However, the new continuous prepolymerization device realizes continuous mixing and reaction of raw materials by precisely controlling the reaction temperature (80-90℃) and stirring speed (500-800rpm), reducing the dispersion index of prepolymers to 1.8-2.2, and controlling the batch performance fluctuation within ±3%, providing a stable foundation for the subsequent chain growth reaction.

The technological innovation in the chain growth reaction link is the key to improving the performance of TPU. By introducing a dynamic viscosity monitoring system, it can feedback the reaction process in real time and automatically adjust the amount of chain extender added, which can accurately control the molecular weight of TPU (adjustable from 20,000 to 100,000), and then realize the customization of performance parameters such as hardness (60A-85D) and elasticity (elongation at break 300-800%). For example, when producing high-elastic TPU, by increasing the length of the polyol chain segment, the elongation at break is increased to more than 800%, and the rebound rate is maintained at more than 70%, which is suitable for scenarios such as shoe materials and sports equipment. When producing high-hardness TPU, by adjusting the proportion of diisocyanate, the hardness reaches 85D, and the tensile strength exceeds 60MPa, which can replace some engineering plastics for structural part manufacturing. In addition, the anti-yellowing agents and hydrolysis-resistant agents added during the reaction can realize in-situ compounding, making the anti-yellowing grade of TPU reach above grade 4, and the hydrolysis-resistant life extended to more than 5 years, solving the problem of easy aging of traditional TPU.

The intelligent transformation of equipment provides support for TPU flexible production. The automated batching system deployed on the production line can accurately control the raw material ratio (error ±0.1%) according to the formula requirements, and can quickly switch product models without manual adjustment. The automated pelletizing and screening equipment can real-time eliminate particles with unqualified particle sizes (qualified particle size 2-4mm) through laser detection technology, increasing the product qualification rate to 99.7%. At the same time, the application of the new twin-screw extruder realizes the efficient mixing of TPU and inorganic fillers (such as calcium carbonate, talc powder), with a filling amount of more than 30%, which reduces costs while improving material rigidity, expanding the application of TPU in automotive parts, electronic casings and other fields.

At present, TPU production has formed a flexible production system with "standardization + customization" in parallel. The standardized production line can achieve an annual output of 10,000 tons, producing general-purpose TPU (hardness 80A-95A) to meet the needs of the mass market such as shoe materials and pipes. The customized production line is aimed at high-end fields. For example, medical-grade TPU is used to manufacture infusion tubes and artificial blood vessels through strict control of heavy metal content (lead, mercury, etc. <1ppm) and biocompatibility tests. Flame-retardant TPU meets the UL94 V-0 flame retardant standard by adding halogen-free flame retardants (such as phosphazene), which is suitable for electronic cable coating. This flexible production mode can quickly respond to changes in market demand. For example, switching from producing 80A elastic TPU to 60D high-hardness TPU only takes 2 hours to complete equipment adjustment and formula switching, greatly improving production efficiency.

In addition, the application of green production technology has become a new trend in the development of the TPU industry. By using heat pump cycle technology to recover reaction waste heat, the unit production energy consumption is reduced by 25%. The production wastewater has a reuse rate of 80% after biochemical treatment, reducing water waste. The leftover materials and unqualified products are re-pelletized through screw extrusion, with a recycling rate of more than 95%, realizing resource recycling. These technological innovations not only improve the environmental protection level of the TPU industry, but also further reduce production costs, promoting the penetration of TPU series materials into a wider range of fields.