Isoprene-styrene copolymer

Isoprene-styrene copolymer (CAS 25038-32-8), commercially recognized as Styrene Isoprene Styrene (SIS), is a thermoplastic elastomer block copolymer used across adhesive, sealant, and rubber compounding applications.

It delivers elastic recovery and melt processability without requiring vulcanization, making it a preferred base polymer for hot-melt and pressure-sensitive systems. SIS is the primary base polymer in hot-melt pressure-sensitive adhesives.

These adhesives are used for labels, tapes, and hygiene product construction, where its natural tack and cohesive strength determine bond performance. In roofing and waterproofing membranes, it modifies bitumen to improve low-temperature flexibility.

The material also provides resistance to thermal creep in construction applications. Rubber compounders incorporate it to adjust hardness and elastic recovery in molded and extruded profiles, ensuring high performance in industrial settings.

In household and industrial contact adhesives, SIS contributes to open-time control and peel strength across a range of substrates. Isoprene-styrene copolymer is supplied as pellets, crumbs, or blocks depending on the grade.

Styrene content and diblock ratio are the key specification variables that differentiate commercial grades, with typical styrene content ranging from 14% to 30%. Technical grades are standard for most industrial uses.

Food-contact compliance varies by grade and should be confirmed against applicable regulations. Manufacturers ensure consistency by adhering to strict production protocols to meet specific industrial requirements and performance benchmarks.