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Styrene Isoprene Styrene is a synthetic, large-sized polymer, that works to control the viscosity and forms a film in cosmetics and personal care products.
Styrene Isoprene Styrene has a molecular weight of 172.27 and its chemical formula is C13H16.
Styrene Isoprene Styrene is a highly versatile thermoplastic elastomer that offers the elasticity of natural rubber combined with the processability of plastics, and its triblock molecular architecture allows it to be customized for adhesives, coatings, sealants, hot-melt applications, and a variety of flexible and elastic products across industrial, medical, and consumer markets.
CAS Number: 25038-32-8
Molecular Formula: C13H16
Molecular Weight: 172.26614
Synonyms:styrene-isoprene-styrene, styrene/isoprene/styrene, SCHEMBL218545, VSKJLJHPAFKHBX-UHFFFAOYSA-N, STYRENE/ISOPRENE, ABA BLOCK COPOLYMER;POLYSTYRENE-BLOCK-POLYISOPRENE-BLOCK-POLYSTYRENE;Isoprene - styrene (1:1);STYRENE/ISOPRENE COPOLYMER;Benzene,ethenyl-,polymerwith2-methyl-1,3-butadiene;Styrene,polymerwithisoprrene;Polystyrene-block-polyisoprene-block-polystyrene styrene 22 wt. %;POLYSTYRENE-BLOCK-POLYISOPRENE-BLOCK-POL YSTYRENE, 14 WT. % STYRENE
Styrene Isoprene Styrene, commonly abbreviated as SIS, is a thermoplastic elastomer composed of polystyrene end blocks and a polyisoprene midblock, forming a triblock copolymer that combines the elastic properties of rubber with the processability of thermoplastics.
The polystyrene domains act as physical crosslinks that provide structural integrity and tensile strength at ambient temperatures, while the polyisoprene midblock gives the material its flexibility, resilience, and excellent elongation characteristics, allowing it to stretch under stress and return to its original shape without permanent deformation.
Styrene Isoprene Styrene is a lightweight, tacky, and viscoelastic polymer, which makes it ideal for applications where adhesion, softness, and elasticity are required simultaneously. Unlike vulcanized rubbers, it does not require chemical crosslinking to achieve its elastic properties, meaning it can be processed using standard thermoplastic methods such as extrusion, injection molding, or hot-melt application, offering significant advantages in terms of manufacturing efficiency and recyclability.
Chemically, Styrene-Isoprene-Styrene exhibits high compatibility with oils, resins, and other hydrocarbon-based additives, which allows it to form blends, adhesives, and coatings with customizable performance characteristics, including controlled tackiness, peel strength, and cohesive strength.
Its thermoplastic nature also enables it to be re-melted and re-processed multiple times without significant degradation, making it a versatile material for both industrial and consumer applications.
In addition to mechanical performance, SIS displays good resistance to water, low levels of polar solvents, and mild chemical exposure, although it is less resistant to strong acids, bases, or oxidizing agents.
Styrene Isoprene Styrenes triblock structure allows manufacturers to modify the ratio of styrene to isoprene to tailor hardness, elasticity, and thermal properties, producing materials suitable for a wide range of temperatures and environmental conditions.
Styrene Isoprene Styrene is a highly specialized block copolymer in which two polystyrene end blocks are chemically bonded to a central polyisoprene block, forming a linear triblock structure that behaves like a crosslinked rubber at room temperature but can be processed like a thermoplastic when heated.
This unique molecular arrangement gives Styrene Isoprene Styrene its exceptional combination of elasticity, toughness, and processability, making it suitable for applications that require both mechanical strength and flexibility.
The polystyrene domains act as hard segments that form physical “nodes” providing dimensional stability and tensile strength, while the polyisoprene midblock acts as a soft, elastic segment that absorbs stress, permits elongation, and allows for rapid recovery after deformation.
This makes Styrene Isoprene Styrene particularly advantageous in products where stretchability, resilience, and repeated flexing without permanent deformation are essential, such as in pressure-sensitive adhesives or elastic films.
Melting point: 95 °C
Density: 0.93 g/mL at 25 °C
refractive index: 1.5164-1.5191
solubility: solvents with solubility parameters between 7.7 and 9.4: soluble
form: Transparent or translucent pellets or granules
Odor: Mild aromatic
Viscosity: 5poise25wt. % in toluene(25°CBrookfield)(lit.)
Styrene Isoprene Styrene is also thermally processable, meaning that it can be melted, reshaped, and solidified repeatedly without chemical curing, which simplifies manufacturing and recycling.
Its tackiness and compatibility with hydrocarbon resins, oils, and other polymer additives allow formulators to adjust adhesive strength, peel strength, and cohesive properties to meet specific product requirements.
Additionally, Styrene Isoprene Styrene can be co-extruded with other polymers or applied as a hot-melt adhesive, providing versatility in multilayer structures, laminated films, and coated materials.
From a chemical perspective, Styrene Isoprene Styrene exhibits good resistance to water, mild acids, and bases, and it retains flexibility across a broad range of temperatures, although prolonged exposure to strong oxidizers, UV light, or aromatic solvents may lead to degradation.
Its low density and lightweight nature, combined with soft touch and elastic recovery, make it suitable for applications ranging from medical adhesives, wearable devices, and wound care products to flexible packaging, automotive seals, and vibration-damping materials.
In summary, Styrene-Isoprene-Styrene is a versatile, high-performance elastomeric polymer whose unique triblock structure provides a combination of elasticity, strength, processability, and adaptability, making it a key material for industries that demand flexible, durable, and easily processed polymer solutions.
Styrene Isoprene Styrene is a copolymer of styrene and isoprene monomers.
Styrene Isoprene Styrene is a thermoplastic elastomer material that is well-regarded for its excellent flexibility and wear resistance.
At room temperature, this copolymer exhibits rubber-like elasticity, yet it can be processed and molded like plastic when heated.
This unique property allows for a wide range of applications across various fields.
Typically appearing as yellow to pale yellow granules, Styrene Isoprene Styrene is visually distinguishable from other materials.
These granules can be melted and reformed during processing to create products of various shapes and sizes.
Due to its good flexibility and durability, Styrene Isoprene Styrene has significant advantages in manufacturing automotive parts, wire and cable coatings, hoses, seals, and other products that require impact resistance and abrasion resistance.
Additionally, it boasts good aging resistance and chemical corrosion resistance, further expanding its application range.
Whether exposed to harsh external environments or in contact with various chemicals, this material maintains stable physical and chemical properties.
Therefore, Styrene Isoprene Styrene has broad application prospects in industries such as construction, medical devices, and sports equipment.
Uses:
Component of hot melt adhesives, sealants, asphalt and oil gels.
Modifier for polymers, thermosets and general rubber compounding.
Direct molded or extruded auto parts, sporting goods, footware and film.
Styrene Isoprene Styrene is extensively employed in applications where a unique combination of elasticity, thermal processability, and adhesive properties is required.
In the pressure-sensitive adhesive (PSA) market, Styrene Isoprene Styrene is highly valued for its ability to provide strong initial tack, long-term adhesion, and cohesive strength, making it ideal for sticky labels, tapes, protective films, and graphic overlays.
Its elastic recovery ensures that the adhesive maintains its performance after repeated stretching or mechanical stress, which is particularly important for industrial labeling, packaging, and consumer goods that undergo handling and transportation.
Beyond adhesives, Styrene Isoprene Styrene is also utilized in hot-melt adhesive systems, where it is incorporated into formulations that flow under heat and solidify upon cooling, providing rapid bond formation without the need for solvents.
These adhesives are widely used in packaging, woodworking, bookbinding, and assembly of automotive and electronic components, where the combination of flexibility, durability, and strong adhesion ensures reliable product performance.
In the coatings and sealants sector, Styrene Isoprene Styrene can be blended with resins, tackifiers, oils, and other polymers to create flexible, protective coatings that resist cracking and delamination.
These coatings are applied in packaging films, protective barriers, and architectural or automotive sealants, where their elasticity and durability help protect surfaces from mechanical stress, vibration, and environmental exposure.
Styrene Isoprene Styrene also finds significant use in medical, personal care, and hygiene applications.
Its soft, elastic, and skin-compatible properties make it suitable for transdermal patches, wound dressings, flexible tapes, and adhesives used in wearable medical devices.
The polymer ensures comfortable application, secure adhesion, and consistent performance, even on moving or delicate skin surfaces.
Styrene Isoprene Styrene is employed in the manufacture of films, laminates, and elastomeric fibers, where its tunable hardness and elasticity allow engineers to produce lightweight, stretchable, and resilient materials used in footwear, athletic equipment, flexible packaging, and protective gear.
The polymer’s compatibility with oils, tackifiers, and other elastomers enables the creation of customized formulations that meet specific mechanical, thermal, and adhesive performance requirements.
Styrene Isoprene Styrene is widely used in industries where a combination of elasticity, adhesion, and thermoplastic processability is required.
One of the primary applications is in pressure-sensitive adhesives (PSAs), where Styrene Isoprene Styrene provides excellent tack, peel strength, and cohesion, making it ideal for labels, tapes, sticky notes, and adhesive films that must adhere to surfaces securely yet be removable without leaving residue.
Its elastic recovery and flexibility also allow these adhesives to maintain performance across repeated stretching, bending, or environmental changes, which is crucial in industrial, medical, and consumer products.
In addition to adhesives, Styrene Isoprene Styrene is used in the coatings and sealants industry, where it is blended with resins, oils, and other polymers to create protective films, elastic coatings, and sealants that are durable, water-resistant, and flexible.
This makes Styrene Isoprene Styrene suitable for protecting electronic devices, packaging materials, and building components where flexibility and impact resistance are necessary.
Styrene Isoprene Styrene is also employed in hot-melt adhesive formulations, which are applied in packaging, woodworking, automotive assembly, and disposable medical products.
In these applications, its ability to flow when heated and solidify upon cooling enables efficient manufacturing processes while providing strong adhesion without chemical curing.
In the medical and personal care industries, Styrene Isoprene Styrene is used in transdermal patches, wound care products, and flexible medical tapes, where its biocompatibility, softness, and elastic recovery ensure comfort and consistent adhesion to skin over extended periods.
Styrene Isoprene Styrene can be incorporated into films, elastomeric fibers, and flexible laminates for lightweight, stretchable, and resilient materials used in footwear, clothing, and sporting goods.
Furthermore, Styrene Isoprene Styrene finds applications in vibration damping, noise reduction, and cushioning materials due to its elasticity and energy-absorbing properties, which are valuable in automotive parts, protective packaging, and industrial equipment.
Its versatility is enhanced by the ability to modify the ratio of styrene to isoprene, allowing formulators to tailor hardness, tack, and elasticity according to the specific functional requirements of each application.
In summary,Styrene Isoprene Styrene is a highly adaptable thermoplastic elastomer that is widely used in adhesives, coatings, sealants, hot-melt systems, medical patches, films, elastomeric fibers, and vibration-damping materials, providing a combination of elasticity, adhesion, flexibility, and processability that meets the demands of diverse industrial, medical, and consumer applications.
Safety Profile:
Styrene Isoprene Styrene is generally considered stable under normal handling conditions, but it can present certain chemical, physical, and environmental hazards that should be carefully managed.
Chemically, Styrene Isoprene Styrene is a polymer composed of styrene and isoprene monomers, which means that under high temperatures, open flames, or strong oxidizing conditions, the polymer can degrade, release styrene vapors, or produce flammable and potentially toxic gases.
Styrene Isoprene Styrene itself is a volatile organic compound (VOC) and may pose respiratory, skin, or eye irritation risks if inhaled as vapor or if dust is generated during mechanical processing.
From a physical hazards perspective, Styrene Isoprene Styrene is a combustible thermoplastic material.
While the solid polymer is not highly reactive, it can catch fire when exposed to sparks, open flames, or excessive heat, producing dense smoke and irritating fumes.
The molten polymer can cause thermal burns upon contact, and heated processing equipment can present fire and burn hazards if proper safety protocols are not followed.
Regarding environmental hazards, Styrene Isoprene Styrene is generally non-water soluble and chemically inert in normal environmental conditions, but improper disposal can contribute to microplastic pollution or long-term persistence in landfills.
Combustion or incineration of SIS can release styrene, carbon monoxide, carbon dioxide, and other potentially toxic compounds into the atmosphere, which may impact air quality and human health.
