Introduction:

What is TPE material?

In the world of plastics, Thermoplastic Elastomers (TPE), also known as thermoplastic rubber, have emerged as a popular material. TPE exhibits the characteristics of low modulus elasticity, with the ability to be repeatedly stretched to more than twice its original length at room temperature. Additionally, it has a high degree of rebound and can almost fully recover to its original length after stress relaxation. Unlike traditional rubber materials, many injection-moldable TPE series are being used to replace thermosetting rubbers. In addition to their basic form, TPEs are extensively used for modifying rigid thermoplastic materials, often to enhance impact resistance. This has become quite common in sheet materials and general molding-grade composites. As a TPE material supplier, this blog aims to give you a little reference on how to perform TPE injection molding and TPE extrusion.

Properties and Applications of TPE:

TPE is a type of material that combines the characteristics of rubber, such as high elasticity, strength, resilience, and moldability. It is environmentally friendly, non-toxic, and safe to use. TPE offers a wide range of hardness, excellent adhesion properties, soft touch, weather resistance, fatigue resistance, heat resistance, and superior processing performance. It does not require vulcanization and can be recycled, reducing costs. TPE can be both used for secondary injection molding, where it is bonded to base materials such as PP, PE, PC, PS, ABS, and PA, as well as for standalone molding.

Advantages of TPE:

Thermoplastic elastomers combine the processing properties of thermoplastic plastics TPE Pellets with the physical properties of vulcanized rubber, making them a combination of the best of both worlds. TPE is rapidly gaining ground in areas that were traditionally dominated by vulcanized rubber. Over the past decade, the rapid development of the electronics, telecommunications, and automotive industries has greatly boosted the TPE market.

Material TPE Processing Techniques for Extrusion:

1. Ensure proper drying before extrusion. Typically, material drying is carried out using hopper-type drying at 80℃ for 2 hours or tray drying at 100℃ for 1 hour. For tray drying, it is recommended to maintain a tray thickness of up to 5cm. The presence of surface imperfections, bubbles, or easy breakage of extruded profiles suggests excessive moisture content in the raw material.

2. Strive for low-temperature extrusion. While ensuring good plasticization quality, try to reduce the extrusion temperature. When the extruded material has a uniform color on the surface and a slight gloss when exiting the die, it indicates good plasticization quality. If the surface is highly glossy, the extrusion temperature can be further reduced.

3. Set temperature profiles that resemble a parabolic curve, with the middle section of the screw having the highest temperature, followed by the feeding section and then the die head. It's important to adjust the die head temperature based on the distance between the screw tip and the die head exit. Longer distances require slightly lower die head temperature (around 10-20℃ lower), while shorter distances can have die head temperature lowered by 30-50℃. Typical temperature settings are 170℃ (feeding section), 180℃ (middle section), 190℃ (front section), and 180℃ (die head). If instability or low melt strength is observed during extrusion, refer to the technique mentioned in point 2.

4. Clean the die head before changing materials, even if using the same grade of TPE resin raw material. If the raw material was not properly dried and subsequently dried again, it is necessary to clean the die head. If surface imperfections, instability during extrusion, or easy breakage of extruded profiles occur after material change, immediately dismantle and clean the die head.

5. Gradually increase the extrusion speed to avoid instability caused by rapid extrusion. Increase the speed at intervals of 3-5 minutes until the desired speed is reached.

Material TPE Processing Techniques for Injection Molding:

1. For strict surface requirements of the molded product, ensure proper drying before injection molding. Typically, material drying is carried out using hopper-type drying at 80℃ for 2 hours or tray drying at 100℃ for 1 hour. It is recommended to use tray drying, keeping the tray thickness within the appropriate range. If the molded product has bubbles on the surface, internal voids when cutting the product, or scattered silver wires on the surface, it indicates excessive moisture content in the raw material.

2. Strive for low-temperature injection molding. While ensuring good plasticization quality, try to reduce the barrel temperature. Increase the injection pressure and screw speed to lower the melt viscosity and improve fluidity. When the injected material has a smooth surface with a slight gloss, it indicates good plasticization quality. If the surface is highly glossy, the barrel temperature can be further reduced. Technique 2 can reduce cooling time, thereby increasing production efficiency.

3. Set temperature profiles that resemble a parabolic curve, with the middle section of the barrel having the highest temperature, followed by the feed section and then the nozzle. Typical temperature settings are 170℃ (feed section), 180℃ (middle section), 190℃ (front section), and 180℃ (nozzle). If internal swelling (trapped gas) occurs in the molded product or if the gate is easily broken during demolding, refer to technique 2.

4. Minimize the holding pressure during injection. Generally, the holding pressure should be lower than the injection pressure. The holding time is determined by monitoring the weight of the product, ensuring that the weight no longer increases, or based on acceptable shrinkage marks. If the gate is easily broken during demolding, reducing the holding pressure may be effective.

5. If there are several injection stages, start with a slow injection speed and gradually increase it to allow easy venting of internal gases. If internal swelling (trapped gas) or surface marks occur, follow technique 2. If there are no multiple injection stages, simply reduce the injection speed.

Conclusion:

Thermoplastic Elastomers (TPE) offer a unique combination of rubber-like properties and thermoplastic processability. With their excellent mechanical properties and ease of processing, TPEs are revolutionizing the rubber industry. The steadily growing demand for TPEs, driven by industries like electronics, telecommunications, and automotive sectors, reinforces their position as a preferred material for various applications. As a TPE manufacturer, we welcome your inquiries and we can provide high-quality TPE materials with competitive prices.

https://www.toponew.com/products/tpe-compound/TPE-20-85
https://www.toponew.com/products/tpe-compound/TPE-20-30