TPU Film Manufacturing Process

The manufacturing process of TPU film mainly includes the following steps:

Raw Material Preparation

Raw Material Selection: The main raw material for TPU film is thermoplastic polyurethane (TPU) granules. Suitable polyester polyols and diisocyanates are selected based on product performance requirements.

Formulation and Mixing: TPU granules are mixed uniformly with other additives such as antioxidants and UV absorbers in a specific ratio to meet specific performance requirements.

Melte Preparation

Heating and Melting: The mixed TPU granules are placed in a melt preparation device and heated under high temperature and pressure to melt them into a homogeneous melt.

Quality Control: During this process, parameters such as melt temperature, pressure, and mixing speed need to be strictly controlled to ensure the uniformity and stability of the melt.

Film Forming

Extrusion Method: The molten TPU is extruded into sheets through an extruder die, then trimmed and wound.

Blow Molding: The extruded TPU film is formed into a tube blank using a ring die. Compressed air is introduced, clamped, and a constant internal pressure is maintained, expanding to the desired outer diameter. After cooling and setting, it is pulled and wound up.

Calendar Method: The TPU melt is continuously calendered into a film using several heated and adjacent rotating shafts. The film thickness is determined by the gap between the last shaft.

Casting Method: Molten TPU melt is cast into a film of the desired thickness through a casting machine nozzle.

Stretching Method: The TPU film is stretched longitudinally and laterally between its softening and melting temperatures. In actual production, biaxial stretching is mainly used to improve film performance.

Cooling and Setting

Cooling Treatment: The extruded or calendered TPU film is rapidly cooled using a cooling device, such as a cold water bath or cooling roller, to solidify and set its shape.

Parameter Control: Parameters such as cooling rate, curing time, and curing temperature need to be strictly controlled to ensure the physical properties and appearance quality of the film.

Post-processing

Cutting and Rolling: The cooled and set film is cut to the required size and rolled onto spools for easy subsequent processing and use.

Quality Inspection: The produced TPU film undergoes quality inspection, including testing for thickness, width, transparency, tensile strength, tear strength, and other indicators to ensure the product meets quality requirements.

Packaging and Storage: The qualified TPU film is packaged and properly stored to prevent damage during storage and transportation.

Special Processes

Electroplating: For TPU films requiring electroplating, the TPU film is laminated with an ABC electroplating film. Through preheating and hot pressing, it achieves excellent electroplating effects and durability.

Coating Treatment: Depending on the needs, the TPU film is coated with various materials, such as scratch resistance, fingerprint resistance, and UV protection, to meet the requirements of different applications.

The production process of TPU film is complex and meticulous. Each step requires strict quality control and parameter management to ensure the final product's performance and quality meet requirements.