Thermoplastic Elastomers
for Automotive Applications

The challenges for the automotive industry are constantly changing: emissions & noise reduction, performance & safety improvement, light weighting, interior air quality, greater comfort and affordability. Kuraray helps achieve these goals by providing a wide range of high performance materials combined with expert technical service ensuring you find the right solution for your specific requirements.

Automotive Interior

Soft-Touch Over Molding

SEPTON™ 4000-series provides excellent oil retention due to its novel soft block structure. Using SEPTON™ 4000-series helps avoid discoloration and staining caused by oil migration. Good haptics, excellent adhesion to common thermoplastics and wide hardness ranges are key advantages of soft-touch over molding with Kuraray’s elastomers. Typical applications include grips, airbag-covers and molded parts for impact modification.



Automotive Exterior

Structural Adhesives


For automotive adhesives Kuraray has developed selected copolymers with diverse functionalities. LIR-403 and -410 are carboxylated Liquid Isoprene Rubber (LIR) for improving adhesion to metal surfaces. Other Kuraray Liquid Rubber (K-LR) copolymers contain vinyl-groups for tailored damping performance. Both LIR & LBR (Liquid Butadiene Rubber) can be incorporated into adhesive and sealant formulations for sharp property modifications. In specific cases, LIR & LBR can also be used as primary components. These properties lead to longer product life times with enhanced sound and damping performance.


Mechanism scheme of Liquid Rubber versus process oil in vulcanized baser rubber >>

Max. load (N) (adhesion) to aluminium  >>



Various grades of SEPTON™ and HYBRAR™ deliver excellent adhesive properties combined with improved temperature and weather resistance for automotive sealants. Certain grades of HYBRAR™ can be foamed and cured during the paint curing process for added damping performance. SEPTON™ 4000-series and SEPTON™ V-series exhibit excellent tensile properties, compression set and oil resistance while maintaining a good surface smoothness.


Formulation example with SEPTON™ 4000-series >>


The narrow molecular weight distribution of Kuraray Liquid Rubber (K-LR) ensures minimal residuals (low VOC’s) for improved quality. With its low glass transition temperature (Tg), K-LR allows formulators to tailor performance over a broad temperature range.

Under the Hood

Hoses, Gaskets and Cables


Liquid Butadiene Rubber (LBR) is used in high performance crosslinked rubber applications where high operating temperatures are common. Kuraray has a range of Liquid Rubbers with high vinyl contents (e.g. LBR-361). These materials provide two functions. First, as a reactive plasticizer without bleeding. Second, they improve curing kinetics similar to conventional coagents. The crucial advantages of incorporating LBR into EPDM rubber include optimum hardness compression set improvement, high hardness compounds, processability, metal adhesion, low VOC’s and no migration with excellent curing kinetics.


Table of properties Liquid Butadiene Rubber>>


In particular SEPTON™ 4000-series with its high loading capacities is widely used in cable applications. The main benefit is to combine thermoplastic processing and adequate elasticity over a wide temperature range.


SEPTON™ V-series is a block copolymer with reactive and cross-linkable hard and soft blocks. Crosslinked SEPTON™ V-series compounds exhibit excellent heat resistance, long term compression set and oil resistance while maintaining good rubber-like properties even at low temperatures. 

Decoration and Protection

Protective Films

Various grades of SEPTON™ and HYBRAR™ are used in protective films. The core chemistry is based on styrenic-block copolymers and allows design flexibility in customizing tack adhesion, strengthening ultimate tack, and residue-free removal. Especially in films for transportation protection or in colored films for temporary color changes Kuraray’s products SEPTON™ and HYBRAR™ offer solutions for all needs.


Film Recipe Example >>

Protective Films (Newly Developed Bio-based HSFC*)- Hydrogenated Styrene-Farnesene Copolymer

Utilizing a new renewable monomer called β-farnesene, Kuraray has developed a new hydrogenated styrene–farnesene copolymer (HSFC), called SEPTON™ BIO-series with a unique chemical structure and differentiated properties. SEPTON™ BIO-series exhibits strong and stable adhesion force across a wide temperature range and has excellent removability without leaving residues, making it ideally suited for use in protective film applications.

*HFSC is a newly developed styrenic block copolymer having a hydrogenated farnesene soft block.

Spray-able Films

Another new application area for SEPTON™ and HYBRAR™ are spray able films. Both SEPTON™ and HYBRAR™ can be easily dissolved in solvent for further processing into a spray-able film formulation. The readymade solution can be bottled in spray cans or multiple use tanks.

Decorative Films

SEPTON™ Q-series is a new HSBC (hydrogenated styrenic block copolymer) with outstanding abrasion resistance, light weight, temperature resistance and weatherability. The product is synthesized with a new polymerization technology and is compatible with Polyolefins and PMMA. This provides the potential for new polymer combinations. For soft touch applications, SEPTON™ Q-series delivers excellent softness and elasticity. Its enhanced durability shows high UV resistance as well as scratch and abrasion resistance. SEPTON™ Q-series is compatible with polyolefins and suitable for co-extrusion and over molding. The biggest advantage compared to TPU is its non-polarity which makes the material compatible with commodity plastics such as PP.



Kuraray Liquid Rubber (K-LR) offers various application possibilities for tire manufacturing. Different grades can be processed in certain tire parts to contribute to a long lasting quality product. K-LR is a favored component in the production of high performance tires. It reduces Mooney viscosity which minimizes migration while improving the processability of the rubber compound in tires. K-LR enhances tire performance significantly by simultaneously controlling the balance of grip, fuel efficiency and wear resistance. K-LR is crosslinkable for superior performance and longer shelf life.



To top