Styrene-ethylene-butylene-styrene thermoplastic elastomer (SEBS)

As a polymer manufacturer, Kuraray offers styrene-ethylene-butylene-styrene (SEBS) as part of its core product range. The important thermoplastic elastomer (TPE) behaves like rubber, but does not undergo vulcanization. SEBS rubber is flexible, strong, has excellent heat and UV resistance as well as good processability. Read below to find out how SEBS is made and what its advantages and applications are.

How is SEBS made?

Thermoplastic styrenic elastomers (TPS) are compounds based on a styrene-butadiene-styrene (SBS) block copolymer or styrene-ethylene-butylene-styrene (SEBS). SBS and SEBS are raw materials, but the two terms are often used to describe the properties of the respective compound.

The history of thermoplastic elastomers goes back about half a century. At that time, a discovery led to the production of block copolymers with the aid of anionic polymerization. This made it possible to construct precise polymer chains with a sequence of styrene repeat units. These were attached to a sequence of butadiene repeat units and ended with another block of styrene units. A SBS block copolymer was the result.

Styrene block copolymers are styrene-based thermoplastic elastomers in which thermoplastic styrene building blocks are chemically coupled with an elastic polymer building block. SEBS is produced by hydrogenation from SBS. In this process, ethylene and butylene mid-blocks are formed by eliminating CC double bonds in the butadiene moiety. As a result of this conversion, SEBS exhibits better thermal stability and weathering resistance while maintaining almost all of its mechanical performance.

Advantages of SEBS

• Inherits the soft-touch characteristics of SBS
• Thermal stability
• Weathering resistance
• UV resistance
• Ozone resistance
• Chemical resistance (oil, detergents, acids, bases, etc.)
• Good abrasion resistance
• Better cost-performance ratio compared to vulcanized rubber processing
• SEBS-based compounds can be used for 2K molding
• Sterilizable

Disadvantages

• Small loss of mechanical performance compared to SBS
• Hydrogenating SBS to SEBS increases the cost of the polymer

Compounds including SEBS

To improve the performance of polymers and engineering plastics, they are often blended with compounds based on SEBS material. SEBS-based elastomers are frequently used as impact modifiers and as flexibilizers or tougheners for clear PP and other materials. Oil, fillers and additives are often added to reduce costs and further modify properties, for example for adhesion to engineering thermoplastics.

SEPTON™ 8000-series

With the SEPTON™ 8000-series, Kuraray uses anionic polymerization techniques to synthesize a hydrogenated SEBS type for its portfolio. With its popular mid-block structure in HSBCs, SEPTON™ 8000-series is an excellent choice. The moderate tensile strength is one of the main features of SEBS polymers. The SEPTON™ 8000-series is widely used for adhesives, automotive parts, personal care products and other applications.

Contact us for more information about the SEPTON™ 8000-series or to receive a sample.

TPS Compounds with SEBS: features & benefits

• Broad range of Shore A hardness
• Completely colorable
• Light weight
• Replacement of hazardous plasticized PVC as well as TPU in various applications
• Compatible with several types of plastics, e.g. PP, PS, ABS, EVA, PBT, PC/ABS, PA, TPU
• Various methods of plastics processing (injection molding, extrusion, blow molding)

TPS compounds with SEBS: applications

• Compounding
• Consumer goods
• Industrial & construction
• Medical
• Mobility
• Sporting goods & footwear
• 3D printing

Interested in what happens when SEBS is exposed to UV radiation for prolonged durations? Read the Polymers article by Garcia-Garcia et al. (2020)