Temperature-Related Aspects of TPE Materials

Preface

To help industry professionals gain a more comprehensive understanding of the temperature-related properties of elastomers, this article discusses TPE in a broad sense. It covers not only styrenic thermoplastic elastomers but also includes TPEE, TPU, TPV, and TPAE elastomers.

Brittleness Temperature of TPE

The brittleness temperature of TPE ranges approximately from -70°C to -20°C. Different types of TPE exhibit different brittleness temperatures, serving as an indicator of their cold resistance. Generally, polyester elastomers (TPEE) have the best cold resistance, styrenic elastomers perform well, while polyolefin elastomers show relatively poorer cold resistance.

Heat Distortion Temperature of TPE

Since TPEs are soft materials and highly diverse, some modified TPEs have heat distortion temperatures that are not fixed values. Thus, this data is typically not provided in TDS sheets. In general, the heat distortion temperature for styrenic TPEs is around 60–100°C. For thermoplastic vulcanizates (TPVs), it can reach around 130°C. Some foreign TPEEs can withstand up to 150°C, and glass fiber-reinforced TPUs can even reach 170°C.

Melting Temperature of TPE

This refers to the temperature at which TPE materials become flowable. The melting temperature is closely related to the composition of the material. Super soft PVC elastomers melt around 100°C, super soft TPES melts between 120–140°C, and typical elastomers with standard hardness have melting temperatures between 160–250°C.

Drying Temperature for TPE

Generally, drying is performed at 60–80°C for 2–3 hours. Preheating and drying the material before molding prevents surface defects like flow marks caused by moisture. TPE pellets are typically dried and dehumidified before packaging, ensuring they are moisture-free. Common styrenic TPEs and TPRs are not prone to moisture absorption and usually do not require drying before molding. However, polyurethane-based elastomers (TPU) and TPU-modified TPEs absorb moisture easily, and drying is recommended before molding.

Processing Temperature of TPE

TPEs can be molded by injection, extrusion, blow molding, vacuum forming, and calendaring. Processing temperatures are related to the melting temperature. Processing temperatures can often be fine-tuned by adjusting injection pressure, extrusion pressure, and shear pressure. Due to the wide variety of TPE formulations and modifications, there is no fixed processing temperature. It is recommended to refer to the TDS provided by material suppliers and adjust according to actual processing conditions.

Mold Temperature for TPE Molding

Typically, mold temperatures are set between 30–50°C. This is suitable for most TPEs such as styrenic and polyolefin-based elastomers. For temperature-sensitive polyester elastomers like TPU and TPEE, higher mold temperatures may be appropriate.

Decomposition (Carbonization) Temperature of TPE

Soft PVC and thermoplastic polyurethane (TPU) have poor high-temperature stability and begin decomposing gradually above 200°C. In contrast, styrenic and polyolefin TPEs have decomposition temperatures exceeding 300°C.

Container Temperature for TPE Products

This refers to the temperature that exported TPE products can withstand inside shipping containers without deforming due to heat. Typical container temperatures range from 65–70°C, which most TPE materials can handle.

Service Temperature of TPE

Service temperature refers to the range in which TPE products do not become brittle, soften, or deform, maintaining normal functionality. Theoretically, the service temperature range lies between the brittleness temperature and the heat distortion temperature. Typically, styrenic TPEs have a service temperature of -60°C to 100°C, while thermoplastic polyester elastomers (TPEE) can maintain performance between -70°C and 150°C. This makes TPEEs widely applicable in high-end consumer goods, daily-use products, as well as aerospace and military fields.

Additional Knowledge: Common Types of Thermoplastic Elastomers (TPE)

TPE materials refer to all thermoplastic elastomers that exhibit rubber-like elasticity and can be directly processed without vulcanization. They are also commonly known as thermoplastic rubbers. TPEs include styrenic thermoplastic elastomers (SBS), thermoplastic polyurethanes (TPU), thermoplastic polyolefins (TPO), and thermoplastic polyester elastomers (TPEE).

1. Styrenic Thermoplastic Elastomers (SBS)

This includes styrene-butadiene block copolymers (SBS) and their hydrogenated versions (SEBS), along with modified materials such as TPS and TPES. (Note: TPS is sometimes referred to as TPR, and TPES as TPE in the industry, though these terms differ from the general category of TPE materials.)
SEBS and SBS are often used to modify polymers, enhance toughness, and serve as tackifiers for adhesives, coatings, and inks. Modified materials like TPES and TPS offer more flexible physical properties and hardness, making them widely used in toys, household products, fitness equipment, automotive accessories, medical devices, footwear, and cables. Globally, styrenic elastomers have the largest consumption volume among TPEs.

2. Thermoplastic Polyurethane Elastomers (TPU)

TPU stands for Thermoplastic Urethane and is known for its high transparency and elasticity. TPUs are categorized by molecular structure into polyester and polyether types, and by processing methods into injection-grade, extrusion-grade, and blow molding-grade.
TPUs feature excellent wear resistance, high mechanical strength, adjustable hardness (Shore 60A–72D), oil resistance, water resistance, and mold resistance. They are extensively used in automotive parts, mechanical components, footwear, cables, tubing, hoses, and calendared products.

3. Thermoplastic Polyolefin Elastomers (TPO)

TPOs are composed of rubber and polyolefins. The rubber components usually include EPDM, NBR, and butyl rubber, while the polyolefin components mainly consist of polypropylene (PP) and polyethylene (PE).
TPOs have become major materials in the automotive and appliance industries, with automotive applications accounting for over 75% of total production. EPDM/PP blends, also called TPV, are the most widely used TPO products. By improving formulations, TPOs can achieve aging resistance, flame retardancy, anti-static properties, and more. Automotive and cable applications dominate TPO usage.

4. Thermoplastic Polyester Elastomers (TPEE)

TPEEs are block copolymers composed of polyester hard segments and polyether soft segments. The soft segments form an amorphous phase with uncrystallized polyester, while the hard segments crystallize into microdomains that act as physical crosslinks.
TPEEs combine the elasticity of rubber with the strength of engineering plastics. The soft segments impart flexibility, while the hard segments contribute to mechanical strength and durability.

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