Styrene block copolymers are the largest, and perhaps the most widely used, category of thermoplastic elastomers. They consist of hard styrene intermediate blocks and soft-end blocks from raw materials such as butadiene or isoprene, exhibiting a unique multiphase structure. Generally, the structure of a multiphase compound can be described as a poly(styrene-b-elastomer-b-styrene) structure. It is obtained through block copolymerization.
Styrene block copolymers are widely used because they blend well with a variety of materials, including additives, resins, and fillers. They are characterized by high elasticity, tensile strength, and abrasion resistance. The products are colorless and available in a variety of hardnesses. They can be designed to function over a wide temperature range and exhibit varying degrees of viscosity and damping.
The exact properties of this thermoplastic elastomer depend on the chemical structure of the elastomer block. This allows for a high degree of customization.
The following main types are available:
- SEP: Styrene-ethylene-propylene block copolymer
- SEPS: Styrene-ethylene-propylene-styrene block copolymer
- SEEPS: Styrene-ethylene-ethylene-propylene-styrene block copolymer
- SEEPS-V: S-ethylene-ethylene-propylene-S block copolymer (S: crosslinkable hard block)
- SBS: Styrene-butadiene-styrene block copolymer
- SEBS: Styrene-ethylene-butene-styrene block copolymer
- SIS: Styrene-isoprene-styrene block copolymer
In addition, unique vinyl-rich thermoplastic elastomers are available as alternatives to PVC without the need for plasticizers:
- V-SIS: Vinyl-rich SIS
- V-SEPS: Vinyl-rich SEPS
- V-SEEPS: Vinyl-rich SEEPS
Kuraray offers SEPTON™ and HYBRAR™ styrene block copolymers for a wide range of applications, such as thermoplastic elastomer compounds, polymer modification, adhesives, PVC alternatives, damping applications, etc.