Thermoplastics-Elastomer Processing Equipment

There are six generic classes of commercial TPEs:

Styrenic block copolymers, TPS (TPE-s)

Thermoplastic polyolefinelastomers, TPO (TPE-o)

Thermoplastic Vulcanizates, TPV (TPE-v or TPV)

Thermoplastic polyurethanes, TPU (TPU)

Thermoplastic copolyester, TPC (TPE-E)

Thermoplastic polyamides, TPA (TPE-A)

Not classified thermoplastic elastomers, TPZ

TPE (Thermoplastic Elastomer) processing requires specialized equipment and knowledge. Unlike rubber processing, TPEs can be processed using standard plastics machinery such as injection molding and extrusion. However, TPE processing is different from traditional plastics processing due to the unique properties of TPEs, which combine the characteristics of both rubber and plastic materials.

When it comes to processing TPEs, the screw design is critical to achieving a quality product. The screw design for TPE processing typically involves a low compression ratio, shallow flight depth, and a low shear rate. The low compression ratio allows for effective melting and mixing of the TPE material without damaging the material’s unique properties. Shallow flight depth reduces the shear rate, minimizing the risk of material degradation. Additionally, the screw L/D ratio for TPE processing is typically higher than that used for plastic processing, ranging from 18:1 to 24:1.

In terms of machinery, TPEs can be processed using standard injection molding machines or extruders. However, specialized equipment may be required to process certain types of TPEs, such as those with high viscosity or low melt flow index.

Overall, TPE processing requires specialized equipment and knowledge, and screw design is critical to achieving high-quality products. Manufacturers should consult with experts in TPE processing to ensure optimal processing conditions and achieve the desired product characteristics.

TPE materials require a specialized feed screw design to ensure optimal processing conditions and product quality. The feed screw design for TPEs typically involves a low compression ratio, shallow flight depth, and a low shear rate. Here’s a more detailed breakdown of each of these design elements:

Low compression ratio: TPEs require a low compression ratio to prevent overworking the material and damaging its unique properties. A typical compression ratio for TPE processing might be in the range of 1.5:1 to 2.5:1.

Shallow flight depth: TPEs also require a shallow flight depth to minimize shear forces and reduce the risk of material degradation. Shallow flight depth also allows for more effective mixing of the material. A typical flight depth for TPE processing might be in the range of 0.2 mm to 0.5 mm.

Low shear rate: TPEs have a relatively low shear rate compared to other materials, so the screw design must be optimized to provide sufficient shear without causing degradation. This can be accomplished by adjusting the flight depth and the clearance between the screw and the barrel. A typical shear rate for TPE processing might be in the range of 50 to 200 s^-1.

In addition to these design elements, the feed screw for TPE processing may also have a special coating or treatment to enhance its wear resistance and prevent buildup of the TPE material on the screw surface. Some common coatings used for TPE processing include nitriding, tungsten carbide, and chromium plating.

Overall, the feed screw for TPE processing requires a specialized design to ensure optimal processing conditions and product quality. Manufacturers should work with experts in TPE processing to select the appropriate screw design for their specific application.