TPU is a thermoplastic polyurethane elastomer rubber. It is mainly divided into the polyester type and polyether type. It has a wide hardness range (60HA-85HD). It is characterized by excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low-temperature resistance, and good oil, chemical and environmental resistance.
TPU is widely used in shoe materials, pipes, films, rollers, cables and wires and other related industries due to its good processability, weather resistance and environmental protection.
The so-called elastomer refers to the polymer material with glass transition temperature lower than room temperature, elongation at break >50%, and good recoverability after removal of external force. Polyurethane elastomers are a special class of elastomers. Polyurethane elastomers have a wide range of hardness and properties. Therefore, polyurethane elastomers are a kind of polymer material between rubber and plastic.
Thermoplastic polyurethane rubber is crosslinked by intermolecular hydrogen bonds or slight crosslinking between macromolecular chains. With the increase or decrease of temperature, these two crosslinking structures are reversible. The intermolecular force is weakened in the molten state or solution state, and after cooling or solvent volatilization, there is a strong intermolecular force connected together to restore the properties of the original solid.
TPU Modified Granulation Process
- Twin screw extruder – screen change – water-cooling strand pelletizing granulation auxiliary machine – water trough – dryer – pelletizer – vibrating screen – silo
- Twin screw extruder – melt pump – screen change – Underwater granulation auxiliary machine – underwater pelletizer – water circulation system – centrifugal dehydrator – vibrating screen – silo
TPU reaction process
Polyol material tank, MDI material tank, BDO chain extender three liquid quantitative mixer – Twin Screw Extruder – melt pump – screen change – Underwater granulation auxiliary machine – underwater pelletizer – water circulation system – centrifugal dehydrator – vibrating screen – silo
Q&A of TPU processing:
- Does TPU need to be dried? What are the problems caused by not drying? What is the moisture content of TPU?
TPU will quickly absorb moisture when exposed to the air so the material must be dried before the molding process, otherwise, the water will be transformed into moisture at high temperature, which will bring many obstacles to the processing, such as colloidal foaming, melt thinning, serious product flow marks, material physical properties decline, etc. - What is the relationship between TPU hardness and processing temperature?
The soft hardness of TPU is often expressed by shore A and shore D. what controls the soft hardness? The soft hardness of TPU is mainly controlled by the internal molecular structure, that is, the ratio of the soft segment to the hard segment of TPU. In the molecular characteristics, soft and hard is the performance of molecular chain rigidity. The thermal stability, that is, the temperature resistance of the hard segment is higher than that of the soft segment. Relatively speaking, the relatively soft TPU is less stable than the relatively hard segment during processing.
Cowin’s TPU Twin Screw Extruders
TPU is a thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber. It is a kind of elastomer that can be plasticized by heating and dissolved by the solvent. It has excellent comprehensive properties such as high strength, high toughness, wear resistance, oil resistance and good processing performance. It is widely used in national defence, medical treatment, food and other industries. The intermolecular force is weakened in the molten state or solution state, and after cooling or solvent volatilization, there is a strong intermolecular force connected together to restore the properties of the original solid.
Advantages of TPU granulation equipment:
- Touch screen and PLC are combined with intelligent control to reduce labor and material waste;
- Beautiful grain shape, uniform blanking for extrusion and injection molding, stable products, and easy for customers to use; The material is pelletized in water and dehydrated for cooling, which can avoid the adhesion of materials with high viscosity during processing, significantly improve the appearance of pellets and reduce the moisture content of pellets.
- Used for plastic processing requirements that cannot be met by ordinary granulation.
For example, processing and production of hot melt adhesive, elastomer, grafting material and raw material granulation.
Technical Specifications of Extruder：
According to different applications & outputs, there are many different choices for extruders.
CHT-B Twin Screw Extruder
| Model | Diameter(mm) | L/D | Speed(rpm) | Power(kw) | Output(kg/h) |
| CHT52-B | 51.4 | 24-80 | ~600 | ~55 | ~300 |
| CHT65-B | 62.4 | 24-80 | ~600 | ~90 | ~450 |
| CHT75-B | 71 | 24-80 | ~600 | ~132 | ~700 |
| CHT85-B | 81 | 24-80 | ~600 | ~250 | ~1200 |
| CHT95-B | 93 | 24-80 | ~600 | ~315 | ~1800 |
CHT-D High Torque Twin Screw Extruder
| Model | Diameter(mm) | L/D | Speed(rpm) | Power(kw) | Output(kg/h) |
| CHT52-D | 51.4 | 24-80 | ~800 | ~110 | ~450 |
| CHT65-D | 62.4 | 24-80 | ~800 | ~160 | ~900 |
| CHT75-D | 71 | 24-80 | ~800 | ~250 | ~1500 |
| CHT85-D | 81 | 24-80 | ~800 | ~315 | ~1800 |
| CHT95-D | 93 | 24-80 | ~800 | ~550 | ~2800 |
| CHT110-D | 110 | 24-80 | ~800 | ~600 | ~3200 |
CHT-MAX High Torque Twin Screw Extruder
| Model | Diameter(mm) | L/D | Speed(rpm) | Power(kw) | Output(kg/h) |
| CHT52-MAX | 51.4 | 20-80 | ~1000 | ~160 | ~700 |
| CHT65-MAX | 62.4 | 20-80 | ~1000 | ~250 | ~1500 |
| CHT75-MAX | 71 | 20-80 | ~1000 | ~355 | ~2000 |
| CHT85-MAX | 81 | 20-80 | ~1000 | ~400 | ~2500 |
| CHT95-MAX | 93 | 20-80 | ~1000 | ~600 | ~3500 |
| CHT120-MAX | 122 | 20-80 | ~1000 | ~700 | ~5000 |
| CHT135-MAX | 133 | 20-80 | ~600 | ~800 | ~6000 |
| CHT160-MAX | 158 | 20-80 | ~600 | ~1200 | ~10000 |
Customer Case
Project 1
- Factory Location: China
- Equipment: CHT65 Twin Screw Extruder
- Application: TPU
- Output:500 kg/h
- Date:2018.08
Project 2
Factory Location: China
Equipment:CHT65 Twin Screw Extruder
Application:TPU
Output:500 kg/h
Date:2017.11
