What are styrenic block copolymers?

The fundamental mechanical characteristics of SBCs are their rubber-like elastic properties combined with excellent softness. This makes them well-suited for soft-touch applications in various industries, such as sporting goods and footwear, consumer goods, mobility, electronics and medical applications. For a full list, see below.

For applications that require higher hardness and mechanical strength, other TPEs such as TPUs, TPCs and TPAs may be more suitable.

SBCs are lower in density compared to TPUs, TPAs, TPCs and TPVCs, and comparable density with TPO and TPV.

The heat resistance of SBCs is dependent on the chemical structure and glass transition temperature of the end-blocks. The maximum operation temperature is ~ 80℃. The brittleness temperature is the point at which the polymer transitions from a rubbery state into glass, which is much harder and more fragile. The low brittleness temperature of SBCs allows it to be used in low temperature applications requiring good impact and flexibility.

For observed scores, refer to the table above.

SBCs have a narrow molecular weight distribution compared to other TPEs, as TPS is produced by living anionic polymerization.

Unhydrogenated/non-hydrogenated styrenic block copolymers (USBCs) consist of styrene and diene monomer units arranged in a block-like structure. The diene block can be polybutadiene (PB) or polyisoprene (PI). USBCs have not undergone any hydrogenation process, so they retain their unsaturated diene block.

This makes them more reactive compared to their hydrogenated counterparts, so they can be further customized through chemical reactions such as crosslinking or functionalization. They display excellent elastomeric properties and lower processing costs compared to HSBCs.

However, due to the unsaturated diene and the susceptibility to degradation, they have lower thermal stability, reduced chemical resistance and they are more susceptible to aging. USBCs are more prone to developing a yellowish tint over time, which may not be critical for some applications, but problematic for others – such as packaging and medical, where transparent TPEs are preferred.

Hot-melt adhesives are another common application for SBCs. SBCs are an essential component in providing adhesive properties. Kuraray offers materials with excellent processability and performance characteristics.

Additional resources on hot-melt adhesives can be found here:

• Adhesives, coatings and sealants
• Polymer adhesives

SBCs provide broad versatility, allowing customers to tailor their polymers for specific applications across a wide range of industries. From automotive components to packaging materials, construction products to consumer goods, SBCs have proven their worth in countless innovative solutions.

By incorporating SBCs into polymer blends, customers can enhance the lifespan and durability of products, reducing the need for frequent replacements and minimizing waste. SBCs can be useful as a modifier for polypropylene (PP), polyethylene (PE), polystyrene (PS), polycarbonate (PC), acrylonitrile-butadiene-styrene resins (ABS), and polyphenylene ether (PPE).

The improved impact resistance and flexibility provided by SBCs contribute to longer-lasting, more durable products resulting in reduced environmental impact.

SBCs also enable the creation of lightweight yet strong polymer solutions reducing the overall material consumption and carbon footprint. Their versatility allows for optimized processing characteristics by reducing energy consumption during the manufacturing processes. Learn more about SBCs as polymer modifiers.

When it comes to achieving precise viscosity profiles, SBCs excel as highly efficient and versatile viscosity modifiers. These polymers have the ability to significantly change the viscosity of lubricant oils at low concentrations, providing exceptional thickening capabilities.

One of the standout features of SBCs is their shear stability, ensuring that the viscosity remains consistent across a range of various shear conditions and temperatures. This makes them ideal for applications involving intense mechanical forces where stability and reliable flow control are crucial. Learn more about SBCs as viscosity index improvers.