Thermoplastic elastomers (TPE) are a class of copolymers that have properties similar to rubber but can be processed like thermoplastics. Common types of TPEs include styrene block copolymers (SBCs), thermoplastic polyurethanes (TPUs), thermoplastic copolyesters (TPCs), and thermoplastic polyamides (TPAs). TPEs are used in a wide range of applications including automotive parts, footwear, consumer goods, medical devices, sports equipment, and more. Die-casting also provides some surface finish.
What Material Is TPE Made Of?
Thermoplastic elastomers (TPEs) are made from a combination of hard plastic and soft elastic polymer materials. Some common materials used to make TPEs include:
- Styrenic block copolymers (SBCs) – Made from polystyrene (hard) and polybutadiene or polyisoprene (soft). Examples are SBS, SIS, and SEBS.
- Thermoplastic polyurethanes (TPUs) – Made from rigid polyurethane segments and flexible polyether or polyester soft segments.
- Thermoplastic copolyesters (TPCs) – Made from rigid aromatic polyesters and flexible aliphatic polyesters.
- Thermoplastic polyamides (TPAs) – Made from rigid polyamides and flexible polyether or polyester soft segments.
- Thermoplastic vulcanizates (TPVs) – A blend of rubber particles dispersed in a thermoplastic matrix.
- Thermoplastic polyolefins (TPOs) – A blend of polypropylene plastic and ethylene propylene rubber.
- Thermoplastic silicone elastomers – Made from hard silicone resins and soft silicone gels.
- Thermoplastic copolyamides (TPCAs) – Made from rigid polyamide segments and soft polyether or polyester segments.
TPE Injection Molding Parameter Standards
- -Melt Temperature: 360-430°F (182-221°C)
- -Mold Temperature: 50-100°F (10-38°C)
- -Injection Pressure: 10,000-15,000 psi (69-103 MPa)
- -Holding Pressure: 3000-8000 psi (21-55 MPa)
- -Back Pressure: 50-100 psi (0.3-0.7 MPa)
- -Injection Speed: Medium to High
- -Screw Speed: 50-200 rpm
- -Cushion: 25-50% of shot size
- -Cooling Time: 15-60 seconds
- -Clamping Force: 3-5 tons/in2 (420-700 kg/cm2)
- -Shot Size: 25-75% of maximum
- -Regrind Usage: 10-25%
How to Choose the Right TPE Material?
Here are some tips for choosing the right TPE material for your application:
- Consider the key properties needed – hardness, elasticity, resistance to oils/chemicals, temperature stability, etc. Different TPE types offer different properties.
- Match the material to the end-use conditions – will the part be exposed to sunlight, oils, and moisture? Select a TPE that can withstand those conditions.
- Evaluate mechanical requirements – tensile strength, compression set, and abrasion resistance needed. Select a TPE that meets those needs.
- Consider processing method – some TPEs like TPUs and copolyesters are better for extrusion, while others like SBCs and TPVs are better for injection molding.
- Review FDA compliance if required – some TPEs are FDA-approved for food contact or medical devices.
- Consider modifications like color, lubricity, anti-static, and UV resistance if needed. Many TPEs can be modified.
- Analyze cost trade-offs – higher performance TPEs usually cost more. Balance properties and cost.
- Get TPE samples to test for all critical requirements. Work with your TPE supplier.
- Based on the application, consider factors like recycling, adhesion, shelf life, etc..