The production process of TPU (Thermoplastic Polyurethane) pellets mainly includes steps such as raw material formulation, melt extrusion, injection molding, cast elastomer molding, and mixed elastomer molding.
The raw material formulation of TPU pellets is a crucial step in the production process. The primary raw materials include polyether polyol, polyester polyol, diisocyanate, and chain extenders. The selection and formulation of these materials directly affect the final product's quality and performance. For example, polyether polyol and polyester polyol provide different physical and chemical properties, while diisocyanate plays a role in cross-linking, enhancing the strength and durability of the material.
Melt extrusion is one of the core processes in TPU pellet production. In this step, the raw materials designed according to the formula are fed into the extruder, where they are melted through high temperature and high pressure. The molten material is then extruded through a die to form pellets of a specific shape. During this process, the control of temperature, pressure, and extrusion speed is critical, as these parameters directly affect the appearance and internal properties of the pellets.
Injection molding is another important process for TPU pellet applications. Before injection molding, TPU raw materials need to undergo a drying process to remove moisture and volatile substances. During injection molding, the barrel temperature is controlled between 170-220°C, and the injection pressure is relatively low, typically between 14-19 MPa. Since TPU materials have high viscosity, strict control of temperature and pressure is necessary during the injection process to ensure proper molding results.
Cast elastomer molding and mixed elastomer molding are also key processes in TPU pellet production. Cast elastomer molding is suitable for large products, where liquid reactants are injected into molds and cured by heating to form the final product.
Mixed elastomer molding involves first generating a viscous rubber-like material from the reactive components, curing it in an oven to produce raw rubber, then mixing it in a mixer, and finally injecting it into molds for cross-linking and molding.
Beiqiao polyurethane can supply many kinds of TUP,such as Extrusion TPU Granules,Film Series TPU Granules,Injection Grade Polyester Based TPU Granules,Moisture Vapor Transmission TPU Granules,Transparent TPU Granules etc,welcome to inquiry