What is a Thermoplastic Elastomer (TPE)?

Thermoplastic Elastomers (TPEs) are low modulus, flexible materials that can repeatedly be stretched at room temperature and return to their approximate original size when stress is released. TPEs are versatile and are used in most market segments, including mobility, agriculture, consumer goods, electrical/electronics/telecommunications, firearms, medical/pharmaceutical, sports/leisure, and wire/cable. TPEs are processed using conventional thermoplastic equipment for extrusion, injection molding, blow molding, blown film, and calendaring. All TPEs are colorable, which adds to their versatility as a resin choice for applications in many sectors.

Our goal as a solutions company is to provide our customers with high-quality resin expertise, consultation and product. Join us in our latest blog on the advantages of Thermoplastic Elastomers and what sub-category TPE resin works best for your project.

What are the different types of TPE

There are various types of thermoplastic elastomers, each offering a unique combination of characteristics and properties. The more common TPEs and their primary attributes are listed below:

SEBS – Styrene-Ethylene/Butylene-Styrene

Description: Polypropylene Compounded with SEBS Synthetic Rubber

Cost: Lowest Cost, Lowest Performance

Properties:

• General Purpose, Unfilled, and Filled Grades
• Glossy, Tacky, Clear, Translucent, Opaque
• Soft Tactile Feel
• Over-Molding, Adhesion to Substrates
• Low Heat Resistance
• Chemical Resistance (Acids, Bases, Alcohols, Detergents)
• Hydrolytic Stability
• UV Stability
• Food Contact and Biocompatible Grades
• Hardness Range 5 Shore A to 95 Shore A

TPV – Thermoplastic Vulcanizate

Description: Polypropylene Compounded with EPDM Rubber

Cost: Moderate Cost, Moderate Performance

Properties:

• Less Tacky then SEBS
• Matte Appearance, Opaque Only
• Over-Molding, Adhesion to Substrates
• High Heat Resistance
• Low Compression Set
• Chemical Resistance (Acids, Bases, Alcohols, Non-Hydrocarbon Based Oils and Substances)
• Food Contact and Biocompatible Grades
• Hardness Range 25 Shore A to 95 Shore A

TPU (Thermoplastic Polyurethane)

Description: Aromatic or Aliphatic Isocyanate Hard Segment Polymerized with Polyester or Polyether Polyol Soft Segment

Cost: Moderate to High Cost, High Performance

Properties:

• Excellent Toughness
• Excellent Abrasion Resistance
• Excellent Cut and Tear Strength
• Good Compression Set
• Glossy, Clear, Translucent, Opaque
• Over-Molding, Adhesion to Substrates
• Food Contact, Biocompatible, UL Listed, and NSF Approved Grades
• Hardness Range 60 Shore A to 80 Shore D

MPR (Melt-Processible Rubber)

Description: Compounded Blend of COPE, Chlorinated Ethylene & Other Proprietary Constituents

Cost: Moderate to High Cost, Moderate to High Performance

Properties:

• Low Squeak
• Good Abrasion Resistance
• Good Chemical Resistance
• Excellent Weatherability and Environmental Resistance
• Maintain Flexibility Over Wide Temperature Range
• Over-Molding, Adhesion to Substrates
• Matte, Clear, Translucent and Opaque
• Hardness Range 50 Shore A to 95 Shore A

COPE (Co-Polyester-Ether)

Description: Ester Hard Segment Polymerized with Polyether Polyol Soft Segment

Cost: High Cost, High Performance

Properties:

• Tough / Resilient / Repeated Flexures
• Creep and Kink Resistant
• Flexible in Low Temperatures
• Excellent High-Temperature Performance
• Good Resistant to Chemicals, Oils, and Solvents
• Glossy, Opaque
• Hardness Range 80 Shore A to 75 Shore D

PEBA (Polyether Block Amide)

Description: Nylon-based Elastomer, Polyamide Hard Segment Polymerized with Polyether Polyol Soft Segment

Cost: High Cost, High Performance

Properties:

• Good Low-Temperature Flexibility and Impact Resistance
• Excellent Dynamic Properties (Resilience, Hysteresis, Repeated Flexures, Flex Fatigue Resistance, Kink Resistance)
• Excellent Hydrolytic Stability
• Low Coefficient of Friction
• Glossy, Opaque
• Hardness Range 75 Shore A to 80 Shore D

How do I go about selecting the proper TPE for my application?

To select the optimal Thermoplastic elastomer for a specific application, one must consider the following:

Physical and Mechanical Property Requirements

What is the end-use requirement for the resin? Application development depends first on how the product will be used in the end. Your resin specialist or machining company will discuss your design in-depth to get a full scope of the project needs.

Prioritization considerations include: hardness, stretch/bounce back, compression set, abrasion/wear/cut/tear resistance, resistance to bending, adhesion to substrates, energy absorption, acoustic dampening, and any reinforcements or enhancements.

Aesthetic and Appearance Requirements

Color-ability and aesthetic look and feel are also another consideration. If the part is a medical prosthetic, then skin tone may be a factor in the resin selection. Or if the item is a toy, the design may call for bright coloration.

Surface feel considerations are: high surface friction or tacky to touch, dry or silicone-like feel, or silky smooth or lubricious. Surface finish options are glossy or matte, and color options are transparent, translucent, opaque or pre-colored.

Environmental Requirements

Plastics come in contact with environments where heat and chemicals are a factor, such as electrical manifolds and medical fluid tubes. These are critical considerations for the design that a resin specialist will discuss with you.

● Temperature Requirement Considerations: What are the minimum and maximum constant use temperatures, and the length of time exposed to extreme temperatures? UV Exposure and Weather Conditions: Indoors or outdoors, permanent or intermittent?

● Chemical Resistance Considerations: Splash exposure or submerged, the temperature during exposure, and chemical types (acid, base, fuel, oil, cleaning solution, etc.)? Load and Flex Issues: Will the part be under pressure, and if so, how much? Or will it be repeatedly flexed or extended?

Regulatory Requirements

Many applications require the TPE to be certified by a regulatory agency or need some form of OEM approval. The most common are REACH SVHC and RoHS compliance, UL certification (flammability and weatherability), OEM automotive approvals, FDA and EU food contact compliance, FDA toy safety compliance, Medical ISO 10993 or USP Class VI compliance, and NSF 51 and 61 compliance.

Manufacturing Process Method

There are several options for machining a resin. Consider how many of an item you are making and what the cost-benefit of your chosen machining process is compared to the item count and what the end-use is.

Options include the following: injection molding, extrusion, blow molding, over-molding, co-extrusion, blown film and calendaring.

Cost Target

Last but not least, cost plays a key role in the manufacturing process. Your resin specialist will guide you through your options on materials and help you to choose the right material. Would additives to the base material help to offset cost and keep the integrity of the end-use product? From a business standpoint, the material must balance material cost and performance.

How may we assist you today?

Amco Polymers offers a broad range of TPE technologies and products to suit a wide variety of purposes and applications.

The world of polymers continues to grow and offers many design, cost and performance advantages to choose from. Let Amco help you today with our experience in selecting the right material for your application at a cost-effective price. Amco Polymers – The Clear Choice in Resin Distribution.