THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

At the macromolecular level, Thermoplastic Rubbers (SBS-SEBS-SIS) are synthesized via precision living anionic solution polymerization using alkyllithium initiators to construct two glassy, rigid Polystyrene end-blocks ("A" hard blocks, glass transition temperature Tg1 ~ +95 to +100 °C) chemically bonded to both ends of a low-glass-transition Elastomeric mid-block ("B" soft block, Tg2 ~ -55 to -90 °C)—where the mid-block is unsaturated 1,3-butadiene in SBS, catalytically hydrogenated saturated ethylene-butylene in SEBS, or unsaturated cis-1,4-isoprene in SIS. Because the aromatic polystyrene end-blocks and the aliphatic elastomeric mid-blocks are thermodynamically immiscible, below +90 °C the polystyrene end-blocks micro-phase separate into rigid 20 to 30 nm spherical or cylindrical nano-domains that act as multifunctional physical crosslink junctions anchoring a continuous three-dimensional elastomeric network!
When heated above the softening temperature of the polystyrene domains (150 to 210 °C) in an extruder, injection molding machine, hot-melt adhesive mixer, or hot bitumen mill—or when dissolved in hydrocarbon solvents—these physical polystyrene domains dissociate reversibly in Thermoplastic Rubbers (SBS-SEBS-SIS), allowing the polymer to flow, wet substrates, or disperse effortlessly and then re-lock into a high-strength elastic network immediately upon cooling without sulfur vulcanization! 

Each of the three polymer classes within Thermoplastic Rubbers (SBS-SEBS-SIS) fulfills a specialized engineering role: SBS delivers high tensile strength (18 to 32 MPa), -90 °C low-temperature flexibility, and exceptional bitumen and polystyrene compatibility for asphalt highways, torch-on roofing membranes, and TPR shoe soles; SEBS features a 100% saturated ethylene-butylene mid-block that resists UV light, ozone, and 250 °C thermal aging while absorbing up to 200–300 phr of white mineral oil for soft-touch TPE overmolding and medical tubing; and SIS features a low-modulus polyisoprene mid-block that delivers unmatched loop tack and peel adhesion in hot-melt pressure-sensitive tapes, labels, and hygiene adhesives.

Partnering with Ataman Kimya for linear and radial grades of Thermoplastic Rubbers (SBS-SEBS-SIS) guarantees strict control over styrene content, diblock/triblock ratio, solution viscosity, melt flow rate (MFR), and antioxidant stabilization. Selecting the exact grade of Thermoplastic Rubbers (SBS-SEBS-SIS) empowers compounders and formulators to optimize softening point in PG-graded asphalts, shear holding power in PSA tapes, and non-blooming weatherability in molded TPE articles.

CAS Number: SBS (Styrene-Butadiene-Styrene Block Copolymer): 9003-55-8 (Benzene, ethenyl-, polymer with 1,3-butadiene); SEBS (Styrene-Ethylene-Butylene-Styrene / Hydrogenated Styrene-Butadiene Block Copolymer): 66070-58-4 (Benzene, ethenyl-, polymer with 1,3-butadiene, hydrogenated); SIS (Styrene-Isoprene-Styrene Block Copolymer): 25038-32-8 (Benzene, ethenyl-, polymer with 2-methyl-1,3-butadiene)
EC Number: Polymer substances exempt from EINECS monomer listing under EU REACH Article 2(9) (NLP / ECHA Polymer List Numbers: SBS: 618-367-6; SEBS: 613-894-8; SIS: 607-506-9; constituent monomers Styrene EC 202-851-5, 1,3-Butadiene EC 203-450-8, and Isoprene EC 201-143-3 are fully REACH registered)
Molecular Formula: SBS: (C8H8)x-(C4H6)y-(C8H8)z; SEBS: (C8H8)x-[-(CH2-CH2)m-(CH2-CH(C2H5))n-]y-(C8H8)z; SIS: (C8H8)x-(C5H8)y-(C8H8)z (High-molecular-weight A-B-A linear or (A-B)nX radial triblock and multi-arm block copolymers)
Molecular Weight: Weight-Average Molecular Weight (Mw by GPC): Linear SBS: 80,000 to 160,000 g/mol; Radial (Star-Branched) SBS: 200,000 to 400,000 g/mol; Linear/High-MW SEBS: 60,000 to 320,000 g/mol; Linear/Radial SIS: 100,000 to 240,000 g/mol (Polydispersity Index Mw/Mn typically 1.05 to 1.25 due to living anionic polymerization)
INCI Name: STYRENE/BUTADIENE COPOLYMER (for SBS), HYDROGENATED STYRENE/BUTADIENE COPOLYMER (for SEBS), and STYRENE/ISOPRENE COPOLYMER (for SIS; CosIng functions: Viscosity Controlling, Film Forming, Binding, and Oil-Gelling Agents in hydrocarbon cosmetic gels and depilatory/medical adhesives)
E Number: Not assigned (Industrial thermoplastic elastomers, polymer modifiers, and adhesive/sealant raw materials; not food additives, though specific non-staining antioxidant grades of SBS, SEBS, and SIS are cleared for indirect food-contact packaging, closures, and adhesives under US FDA 21 CFR 175.105, 21 CFR 177.1810, and EU Regulation (EU) No 10/2011)
Melting Point: Two-Phase Glass Transition (Tg) Behavior (Amorphous Block Copolymers with no crystalline melting point): Soft Elastomeric Mid-Block Glass Transition (Tg1): SBS = -85.0 to -90.0 °C, SEBS = -55.0 to -60.0 °C, SIS = -60.0 to -65.0 °C; Hard Polystyrene End-Block Glass Transition (Tg2): +95.0 to +100.0 °C for all three types; Thermoplastic Melt Processing / Domain Dissociation Flow Range: 150.0 to 220.0 °C (Vicat Softening Point ~65 to 90 °C depending on styrene content)
Boiling Point: Not applicable (Non-volatile high-molecular-weight solid polymers; thermal decomposition onset in air occurs above ~250 to 270 °C for unsaturated SBS and SIS, and above ~300 to 320 °C for saturated hydrogenated SEBS; Flash Point of solid polymer > 280 to 300 °C; Autoignition Temperature ~390 to 440 °C)
Viscosity: Melt Flow Rate (MFR, ASTM D1238 / ISO 1133): SBS (200 °C / 5.0 kg): < 1.0 g/10 min (high-MW radial bitumen grades) to 5.0–25.0 g/10 min (linear footwear/adhesive grades); SEBS (230 °C / 5.0 kg): < 1.0 g/10 min (high-MW oil-absorbing powder grades) to 5.0–35.0 g/10 min (medium-MW injection/adhesive grades); SIS (200 °C / 5.0 kg): 3.0 to 25.0 g/10 min; Solution Viscosity (25% w/w in Toluene at 25 °C, Brookfield LV): 500 to 20,000 mPa·s (cP) depending on molecular weight and linear vs. radial architecture
Density: Specific Gravity at 20–23 °C (ASTM D792 / ISO 1183): SBS: 0.93 to 0.95 g/cm3 (typically 0.94 g/cm3 for 30% styrene grades); SEBS: 0.90 to 0.92 g/cm3 (typically 0.91 g/cm3); SIS: 0.92 to 0.93 g/cm3 (Bulk Density of porous pellets/crumb: 0.30 to 0.45 g/cm3; dense pellets: 0.50 to 0.60 g/cm3)

Most Frequently Encountered Synonyms:
Thermoplastic Rubbers (SBS-SEBS-SIS)
THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)
Styrenic Block Copolymers (SBC)
Styrenic Thermoplastic Elastomers (TPE-S / TPS)
Thermoplastic Elastomers (SBS, SEBS, SIS)
SBS (Styrene-Butadiene-Styrene Block Copolymer)
SEBS (Styrene-Ethylene-Butylene-Styrene Block Copolymer)
SIS (Styrene-Isoprene-Styrene Block Copolymer)
Hydrogenated Styrene-Butadiene-Styrene (H-SBS / SEBS)
Polystyrene-block-polybutadiene-block-polystyrene (SBS)
Polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS)
Polystyrene-block-polyisoprene-block-polystyrene (SIS)
TPR (Thermoplastic Rubber)
Linear SBS / Radial SBS (Star-Branched SBS)
Oil-Extended SBS (OE-SBS)
SBS 1301 (Linear 30% Styrene) / SBS 1401 & 4303 (Radial 30% Styrene)
Europrene SOL T (SBS & SIS series)
Kraton D (SBS & SIS series) / Kraton G (SEBS series)
Vector (SIS & SBS series, e.g., Vector 4111A, 4113, 4114A, 4211A)
Calprene / Solprene (SBS & SEBS series)
Taipol (SBS, SEBS & SIS series)
Termoplastik Kauçuklar (SBS-SEBS-SIS) (Turkish)
Stirenik Blok Kopolimerler (SBS / SEBS / SIS)

WHAT ARE THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)?

Thermoplastic Rubbers (SBS-SEBS-SIS)—known in international polymer nomenclature as Styrenic Block Copolymers (SBCs) and standardized under ISO 18064 as Styrenic Thermoplastic Elastomers (TPS or TPE-S)—are synthetic high-performance elastomers whose molecules are engineered as triblock (A-B-A) or multi-arm radial ((A-B)nX) chains. Unlike statistical random copolymers such as emulsion SBR 1502 (where styrene and butadiene monomers are distributed randomly along the polymer chain, yielding a single intermediate glass transition temperature Tg ~ -50 °C that requires irreversible sulfur vulcanization to prevent cold flow), Thermoplastic Rubbers (SBS-SEBS-SIS) segregate the hard styrene monomers into pure terminal blocks ("A") and the soft diene/olefin monomers into a pure central block ("B").

This block architecture produces a two-phase nano-morphology at room temperature:

The Hard Phase (Polystyrene End-Blocks, "A", 14% to 43% w/w): With a glass transition temperature (Tg) of +95 to +100 °C, the polystyrene end-blocks of adjacent chains cluster together into glassy, sub-visible nano-domains (20 to 30 nm in diameter). Because these domains are smaller than the wavelength of visible light (400 to 700 nm), unfilled Thermoplastic Rubbers (SBS-SEBS-SIS) can be formulated into water-clear transparent articles while the glassy styrene domains lock the elastomer chains against creep and permanent set.

The Soft Phase (Elastomeric Mid-Block, "B", 57% to 86% w/w): Bridging between the rigid polystyrene nano-domains are flexible, low-Tg elastomeric mid-block chains that provide high elongation (500% to 1,200%), low compression set, and sub-zero flexibility:
   - In SBS (Styrene-Butadiene-Styrene, CAS 9003-55-8): The mid-block is unsaturated polybutadiene (Tg ~ -90 °C), offering the lowest glass transition temperature, highest tensile strength, and optimal compatibility with asphaltene/maltene fractions in road/roofing bitumen and polystyrene plastics.
   - In SEBS (Styrene-Ethylene-Butylene-Styrene, CAS 66070-58-4): The mid-block is a catalytically hydrogenated polybutadiene containing ~35%–45% 1,2-vinyl units, converting the unsaturated chain into a completely saturated random ethylene-butylene copolymer (Tg ~ -55 °C). With zero backbone double bonds (C=C), SEBS is virtually immune to UV degradation, ozone cracking, and thermal yellowing during 200–260 °C extrusion/injection molding.
   - In SIS (Styrene-Isoprene-Styrene, CAS 25038-32-8): The mid-block is unsaturated cis-1,4-polyisoprene (Tg ~ -60 °C), which has a high entanglement molecular weight (~6,000 g/mol vs ~1,800 g/mol for polybutadiene) and low Dahlquist plateau modulus—making SIS uniquely receptive to C5 aliphatic tackifying resins for pressure-sensitive adhesives!

HISTORICAL DEVELOPMENT AND EVOLUTION OF STYRENIC BLOCK COPOLYMERS (SBS, SEBS, SIS)

Following Michael Szwarc's landmark discovery of "living anionic polymerization" in 1956, researchers at Shell Development Company (Holden and Milkovich) synthesized the first commercial A-B-A triblock thermoplastic rubbers—SBS and SIS—in the early 1960s, commercializing them in 1965 under the trademark Kraton. For the first time in industrial history, footwear manufacturers, adhesive formulators, and asphalt engineers could process a high-strength rubber in standard thermoplastic extruders, injection molding presses, and hot-melt mixers without sulfur curatives, accelerators, or 20-minute vulcanization press cycles.
In the early 1970s, to overcome the susceptibility of the unsaturated polybutadiene and polyisoprene mid-blocks of SBS and SIS to outdoor UV oxidation, ozone cracking, and high-temperature degradation above 200 °C, second-generation hydrogenated Styrene-Ethylene-Butylene-Styrene (SEBS) polymers were commercialized. Over the ensuing five decades, global production of Thermoplastic Rubbers (SBS-SEBS-SIS) has grown past 2.5 million metric tons per year, serving as the cornerstone of polymer-modified asphalt highways, torch-applied waterproofing membranes, hot-melt packaging/diaper adhesives, and soft-touch consumer and medical TPEs.

MOLECULAR ARCHITECTURE: LINEAR VERSUS RADIAL (STAR-BRANCHED) AND DIBLOCK VERSUS TRIBLOCK

When selecting a grade of Thermoplastic Rubbers (SBS-SEBS-SIS), four structural variables dictate rheological and mechanical performance:

Linear (A-B-A) versus Radial / Star-Branched ((A-B)nX) Architecture:
- Linear Triblock Copolymers (S-B-S, S-EB-S, or S-I-S): Synthesized by sequential monomer addition (polymerizing Styrene first, then Butadiene/Isoprene, then a second charge of Styrene) or 2-arm coupling. Linear grades have lower solution and melt viscosity at a given molecular weight, higher elongation at break, rapid dissolution in warm bitumen or solvents, and smooth melt flow in footwear injection molding and hot-melt adhesive coating.
- Radial / Star-Branched Copolymers ((S-B)nX, where n = 3 or 4 arms coupled around a central silicon tetrachloride SiCl4 or multifunctional ester core): At equal total molecular weight (e.g., Mw = 250,000 to 350,000 g/mol), a 4-arm star-branched radial SBS occupies a smaller hydrodynamic coil volume than a linear chain—resulting in a lower solution viscosity for easier mixing while providing 4 polystyrene anchor blocks per molecule! In Polymer-Modified Bitumen (PMB) and roofing membranes, radial SBS grades form a dense three-dimensional network at lower dosages (3.5% to 5.0% w/w) and elevate the Ring-and-Ball Softening Point by 5 to 12 °C more than linear SBS!

 Styrene Content (% w/w Polystyrene End-Blocks):
- Low Styrene (13% to 22% w/w Styrene, typical of SIS adhesive grades and ultra-soft SEBS grades): Polystyrene domains form isolated spheres in a continuous rubber matrix, delivering low modulus, ultra-soft Shore A hardness (30 to 50 Shore A), and maximum pressure-sensitive tack.
- Medium Styrene (28% to 33% w/w Styrene, the standard for 80% of SBS road/roofing/footwear grades and standard SEBS compounding grades): Polystyrene domains form interconnected hexagonal cylinders in the rubber matrix, providing the optimal balance of high tensile strength (20 to 32 MPa), elastic recovery, and Shore A 65–78 hardness.
- High Styrene (38% to 45% w/w Styrene): Polystyrene domains form alternating lamellae, yielding high hardness (Shore A 85 to Shore D 45), high stiffness, and superior flow for footwear outsoles and HIPS/GPPS impact modification.

Triblock versus Diblock Content (% S-B or % S-I Diblock):
In a pure A-B-A triblock chain (< 1% diblock, such as Vector 4111A or 4211A SIS), both ends of the rubber mid-block are anchored in polystyrene domains, maximizing cohesive shear strength and high-temperature holding power (SAFT). Conversely, intentionally including 15% to 50% w/w of uncoupled A-B diblock chains (such as S-I diblock in hygiene/label SIS grades) introduces "dangling elastomeric chain ends" that lower hot-melt viscosity, reduce plateau modulus, and boost aggressive loop tack and low-temperature peel adhesion!

Porous Crumb ("Fluffy Pellet") versus Dense Pellet versus Micronized Powder Morphology:
- Porous Pellets / Crumb (specific surface area 1 to 5 m2/g) and Micronized Powders are used for rapid bitumen dissolution in PMB asphalt plants, solvent adhesives, and dry-blending with high loadings (100–250 phr) of paraffinic white oil in SEBS compounding.
- Dense Pellets (talc- or silica-dusted) are designed for direct volumetric/gravimetric hopper feeding into twin-screw extruders, hot-melt adhesive kneaders, and injection molding machines.

INDUSTRIAL PRODUCTION AND MANUFACTURING PROCESSES

Commercial Thermoplastic Rubbers (SBS-SEBS-SIS) supplied by Ataman Kimya are manufactured in anhydrous hydrocarbon solution via living anionic polymerization:

 Stage 1 (Monomer & Solvent Purification and sec-Butyllithium Initiation):
  Polymerization-grade cyclohexane solvent, styrene monomer, and 1,3-butadiene (for SBS/SEBS) or isoprene (for SIS) are passed through activated alumina columns to remove trace moisture, oxygen, and TBC inhibitor down to < 1 ppm. In a nitrogen-inerted stainless-steel reactor at 40 to 60 °C, sec-butyllithium (s-BuLi) initiator is charged to initiate every polymer chain simultaneously, Polymerizing the first charge of Styrene to 100% conversion into living polystyryllithium (PS-Li+) with a narrow Poisson molecular weight distribution (Mw/Mn < 1.08).

 Stage 2 (Diene Mid-Block Polymerization and Sequential or Coupled Termination):
  Next, 1,3-butadiene (for SBS) or isoprene (for SIS) is fed into the reactor and polymerized by the living PS-Li+ chains at 60 to 80 °C. (When manufacturing SEBS precursors, a polar microstructure modifier such as tetrahydrofuran THF, diethyl ether, or a ditetrahydrofurylpropane diamine is added to increase the 1,2-vinyl addition of butadiene from ~10% up to 38%–42%, ensuring that subsequent hydrogenation yields an amorphous ethylene-butylene rubber rather than crystalline polyethylene!).
  - For Sequential Linear A-B-A Grades: A second charge of styrene monomer is added to grow the terminal polystyrene block, followed by protonation termination with alcohol/water.
  - For Coupled Linear or Radial (Star) Grades: A difunctional coupling agent (for linear) or a tetrafunctional coupling agent such as silicon tetrachloride (SiCl4, for 4-arm star radial grades) is added to link the living PS-Diene-Li+ arms into a star macromolecule.

 Stage 3 (Selective Catalytic Hydrogenation for SEBS Grades):
  To produce SEBS (CAS 66070-58-4), the living-terminated SBS polymer cement in cyclohexane (having ~38%–40% 1,2-vinyl microstructure in the polybutadiene mid-block) is reacted with hydrogen gas (H2) at 70 to 100 °C and 15 to 35 bar in the presence of a homogeneous Ziegler-type nickel/cobalt carboxylate-triethylaluminum or metallocene titanocene catalyst until >= 98.5% to 99.8% of the aliphatic C=C double bonds in the mid-block are saturated into ethylene-butylene units while leaving the aromatic benzene rings of the polystyrene end-blocks untouched!

 Stage 4 (Antioxidant Stabilization, Steam Stripping / Coagulation, and Pelletizing):
  Non-staining hindered phenolic and phosphite antioxidants (such as Irganox 1010 / 1076 / 1520 and Irgafos 168 / TNPP at 0.3% to 0.8% w/w) are blended into the polymer cement (alongside 15 to 50 phr naphthenic/paraffinic extender oil for Oil-Extended SBS grades). The solvent is flashed off by hot-water steam coagulation stripping or direct devolatilizing extrusion, dewatered in expeller presses, dried in fluid-bed dryers, and dusted with 0.2%–0.8% calcium stearate, amorphous silica, or talc to prevent pellet blocking.

PHYSICAL, MECHANICAL, AND RHEOLOGICAL PROPERTIES OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

Representative specification ranges across Ataman Kimya's portfolio of Thermoplastic Rubbers (SBS-SEBS-SIS) include:
. SBS (Styrene-Butadiene-Styrene, CAS 9003-55-8) — Linear & Radial Grades:
- Styrene / Butadiene Ratio: Typically 30/70 (29%–32% Styrene for PMB Bitumen, Roofing, and Adhesive grades) or 40/60 (39%–41% Styrene for Footwear & Plastic Modification grades)
- Molecular Architecture: Linear A-B-A (e.g., 1301 type, Mw ~110,000–140,000 g/mol) or Radial 4-Arm Star (e.g., 1401 / 4303 type, Mw ~240,000–350,000 g/mol)
- Oil Extension: Dry grades (0% oil) or Oil-Extended grades (15 to 50 phr naphthenic/paraffinic process oil)
- Specific Gravity: 0.93 to 0.95 g/cm3
- Solution Viscosity (25% w/w in Toluene at 25 °C): 1,200 to 5,500 mPa·s (Linear) / 4,000 to 20,000 mPa·s (Radial; or 5.23% in toluene = 10 to 35 mPa·s)
- Melt Flow Rate (200 °C / 5.0 kg): < 0.5 g/10 min (Radial Bitumen Grade) to 3.0–15.0 g/10 min (Linear Footwear/Adhesive Grade)
- Shore A Hardness (ISO 868 / ASTM D2240): 68 to 76 Shore A (30% Styrene dry) / 82 to 88 Shore A (40% Styrene dry) / 45 to 62 Shore A (Oil-Extended)
- Tensile Strength (ASTM D412): 16.0 to 32.0 MPa; Elongation at Break: 700% to 900%; 300% Modulus: 2.2 to 5.0 MPa
- Volatile Matter (105 °C): <= 0.50% to 0.70% w/w; Ash Content: <= 0.20% to 0.40% w/w

 SEBS (Styrene-Ethylene-Butylene-Styrene, CAS 66070-58-4) — Hydrogenated Grades:
- Styrene / Ethylene-Butylene Ratio: 13/87 to 33/67 (most commonly 29/71 to 32/68, ~30% Styrene)
- Degree of Mid-Block Hydrogenation: >= 98.5% to 99.5% (Bromine / Iodine value < 2.0 g/100 g)
- Specific Gravity: 0.90 to 0.92 g/cm3
- Solution Viscosity (10% to 25% w/w in Toluene at 25 °C): 350 to 4,500 mPa·s (High-MW oil-absorbing grades measured at 10% in toluene = 1,000 to 2,500 mPa·s)
- Melt Flow Rate (230 °C / 5.0 kg): < 1.0 g/10 min (High-MW Compounding Powder) to 5.0–30.0 g/10 min (Injection/Adhesive Pellet Grade)
- Shore A Hardness (Neat Polymer): 42 to 80 Shore A (compoundable with white oil + PP from Shore OO 15 to Shore D 40)
- Tensile Strength: 18.0 to 35.0 MPa; Elongation at Break: 500% to 850%
- Color: Brilliant snow-white porous powder/crumb or water-white transparent pellets (YI <= 2.0)

 SIS (Styrene-Isoprene-Styrene, CAS 25038-32-8) — Adhesive & Sealant Grades:
- Styrene / Isoprene Ratio: 14/86 to 30/70 (Tape/Hygiene grades: 15%–18% Styrene; High-Shear Label/Elastic grades: 22%–30% Styrene)
- SI Diblock Content: < 1% w/w (Pure Triblock High-Cohesion Grades like Vector 4111A / 4211A) or 15% to 42% w/w (High-Tack Tape/Label Grades like Vector 4113 / 4114A)
- Specific Gravity: 0.92 to 0.93 g/cm3
- Melt Flow Rate (200 °C / 5.0 kg): 3.0 to 22.0 g/10 min
- Solution Viscosity (25% w/w in Toluene at 25 °C): 400 to 2,200 mPa·s
- Shore A Hardness: 32 to 62 Shore A; Tensile Strength: 12.0 to 25.0 MPa; Elongation at Break: 1,000% to 1,350%

WHY EACH IMPORTANT PROPERTY OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) MATTERS IN PRACTICE

 Mid-Block Saturation vs. Unsaturation (SBS & SIS versus SEBS):
In SBS and SIS, each repeating monomer unit in the mid-block contains an unsaturated carbon-carbon double bond (C=C). While these double bonds provide low glass transition temperatures (-90 °C in SBS, -60 °C in SIS), high tackifier compatibility, and optional sulfur/peroxide crosslinking capability, they are susceptible to cleavage by atmospheric ozone (O3), outdoor UV radiation, and prolonged heating above 200 °C. In SEBS, catalytic hydrogenation saturates > 99% of these double bonds into stable C-C single bonds—allowing SEBS compounds to withstand decades of outdoor desert/marine sunlight, high ozone concentrations, and co-extrusion/overmolding with polypropylene at 220 to 260 °C without yellowing or embrittlement!

 Oil-Absorption Capacity of High-Molecular-Weight SEBS and SBS:
High-molecular-weight porous SEBS (Mw > 200,000 g/mol, such as G1651-type powder) and radial SBS can absorb 100 to 300 parts per hundred rubber (phr) of paraffinic white mineral oil directly into their ethylene-butylene or polybutadiene mid-block phase without plasticizing the polystyrene domains (provided aromatic content of the oil is < 1%). This enables TPE compounders to produce ultra-soft, non-bleeding gels and Shore A 20–60 grips at very low raw material cost.

 Selective Mid-Block versus End-Block Solvation by Resins and Bitumen Maltenes:
- In Polymer-Modified Bitumen (PMB): When 3% to 12% w/w porous SBS is sheared into hot bitumen at 175–185 °C, the elastomeric polybutadiene mid-block swells up to 6 to 9 times its own volume by absorbing the lighter aromatic/saturate maltene oils of the bitumen, turning the SBS into the continuous elastic phase that raises the bitumen softening point above 75–125 °C while keeping the cold-bend flexibility at -20 to -30 °C!
- In Hot-Melt Adhesives (HMPSA): Aliphatic C5 hydrocarbon resins and rosin esters selectively dissolve in the polyisoprene mid-block of SIS to generate aggressive pressure-sensitive tack, whereas aromatic C9 or alpha-methylstyrene resins selectively reinforce the polystyrene end-blocks to increase high-temperature shear creep resistance (SAFT).

WHAT PROBLEMS CAN THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) HELP SOLVE?

. Eliminating Rutting (Summer Permanent Deformation) and Thermal Cracking (Winter Embrittlement) in Asphalt Highways & Roofing: Incorporating 3.5% to 6.0% w/w radial or linear SBS into road bitumen (or 10% to 13% w/w in torch-on roofing membranes) creates an elastic polymer network that prevents wheel-track rutting at +70 °C pavement temperatures and prevents low-temperature cracking down to -25 to -30 °C.

 Replacing Slow, Non-Recyclable Sulfur-Vulcanized Rubber in Footwear and Molded Goods: TPR compounds based on Thermoplastic Rubbers (SBS-SEBS-SIS) injection-mold in 15 to 30 seconds (compared to 5 to 15 minutes for vulcanized SBR/NR rubber), require zero vulcanizing curatives, and allow 100% of runner and sprue scrap to be reground and re-molded immediately.

 Solving Delamination, Yellowing, and Plasticizer Migration in Soft-Touch Overmolding & Medical Devices: SEBS-based TPE-S compounds replace plasticized PVC and vulcanized EPDM in toothbrush grips, tool handles, automotive weatherseals, and IV medical tubing—offering phthalate-free, halogen-free purity, zero oil bleeding, UV/ozone immunity, and direct thermal melt-bonding to Polypropylene (PP) and Polyethylene (PE) substrates (or to ABS/PC/PA when compounded with polar-modified SEBS/TPU).

 Achieving High Loop Tack, Clean Peel, and High-Speed Coating in Hot-Melt Pressure-Sensitive Adhesives (HMPSA): SIS and SBS block copolymers enable 100%-solids, zero-VOC hot-melt adhesives that coat at 150 to 175 °C at line speeds exceeding 300 to 600 m/min for packaging tapes, courier bags, labels, and disposable baby diapers.

 Overcoming Low-Temperature Impact Brittleness in Polystyrene (GPPS / HIPS), Polypropylene (PP), and Recycled Plastics: Adding 3% to 15% w/w SBS or SEBS as a dry-blend impact modifier and compatibilizer increases the Izod notched impact strength of brittle GPPS, HIPS, PP, and recycled PE/PP/PS blends by 200% to 500%.

BENEFITS FOR THE MANUFACTURER AND END USER

- True Vulcanized-Rubber Elasticity with 100% Thermoplastic Recyclability: Physical polystyrene domain crosslinking provides high tensile strength and low permanent set below +80 °C while remelting cleanly above +150 °C.
- Wide Service Temperature Window (-90 °C to +120 °C): SBS retains flexibility down to -85 °C, while hydrogenated SEBS withstands continuous service temperatures up to +100–120 °C and outdoor UV/ozone exposure.
- Exceptional Compounding Versatility (Shore OO 10 to Shore D 50): Easily compounded with polyolefins (PP, PE, EVA), polystyrene, hydrocarbon process oils, tackifying resins, and mineral fillers (CaCO3, talc, silica).
- Rapid Dissolution and Low Processing Energy: High-porosity crumb and low-MFR pellet grades dissolve rapidly in hot bitumen, hydrocarbon solvents, and twin-screw extruders.
- Clean, Non-Toxic, Vulcanization-Free Chemistry: Free of nitrosamines, sulfur accelerators, heavy metals, ortho-phthalates, and halogens.

APPLICATIONS OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

Thermoplastic Rubbers (SBS-SEBS-SIS) are utilized across seven major industrial application sectors:
 Thermoplastic Rubbers (SBS-SEBS-SIS)—specifically Linear and Radial SBS grades—are utilized as the primary elastomeric modifier in Polymer-Modified Bitumen (PMB) for Heavy-Duty Highway Asphalt Pavements, Airport Runways, Bridge-Deck Waterproofing, Torch-On / Self-Adhesive SBS Bituminous Roofing Membranes, and Crack-Sealing Mastics.
 Thermoplastic Rubbers (SBS-SEBS-SIS)—specifically SIS, SBS, and SEBS grades—are used to formulate 100%-Solids Hot-Melt Pressure-Sensitive Adhesives (HMPSA) and Solvent-Borne Contact Adhesives for carton-sealing packaging tapes, self-adhesive paper/film labels, disposable baby diapers & adult incontinence hygiene products, medical transdermal patches, mattress foam bonding, and footwear assembly.
 Also Thermoplastic Rubbers (SBS-SEBS-SIS)—specifically Linear and Oil-Extended SBS grades—are utilized in the injection molding and extrusion of TPR Footwear Outsoles, Unit Soles, Casual/Safety Shoe Midsoles, Heels, and Welting with high wet-slip grip and sub-zero flex-crack resistance.

 For Soft-Touch TPE-S Compounding and Two-Shot Overmolding, Thermoplastic Rubbers (SBS-SEBS-SIS)—specifically Hydrogenated SEBS grades—are used in personal-care toothbrush/razor grips, power-tool handles, kitchenware, children's toys, sporting goods, and consumer electronics housings.
 In Automotive Weatherseals, Window Encapsulation, Under-the-Hood Ducts, Airbag Doors, and Interior Soft-Touch Skins, Thermoplastic Rubbers (SBS-SEBS-SIS) based on high-MW SEBS are employed for ozone/UV durability, low fogging, and low compression set.
 Furthermore, Thermoplastic Rubbers (SBS-SEBS-SIS) are applied in Halogen-Free Flame-Retardant (HFFR) Flexible Wire & Cable Jacketing, Medical Tubing, Syringe Plunger Stoppers, IV Solution Bags, and Pharmaceutical Septa (replacing plasticized PVC and vulcanized isoprene rubber).
 Additionally, Thermoplastic Rubbers (SBS-SEBS-SIS) are utilized as Toughness / Impact Modifiers and Recycling Compatibilizers for General-Purpose Polystyrene (GPPS), High-Impact Polystyrene (HIPS), Polypropylene (PP), Polyethylene (PE), Engineering Thermoplastics (PPE/PPO, PC/ABS, PA), and Oil-Gelled Telecom Cable Filling Compounds & Cosmetic Hydrocarbon Gels.

WHICH INDUSTRIES USE THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)?

- The Highway Asphalt Paving, Polymer-Modified Bitumen (PMB), and Waterproofing Roofing Membrane Industry uses Thermoplastic Rubbers (SBS-SEBS-SIS) (specifically Radial and Linear 30% Styrene SBS) to upgrade bitumen elasticity and temperature susceptibility.
- The Adhesive, Sealant, Packaging Tape, Label, and Nonwoven Hygiene (Diaper) Manufacturing Industry utilizes Thermoplastic Rubbers (SBS-SEBS-SIS) (specifically SIS, SBS, and SEBS) as the elastomeric backbone of hot-melt and solvent-borne adhesives.
- The Footwear, Shoe Sole (TPR), and Sporting Goods Manufacturing Industry relies on Thermoplastic Rubbers (SBS-SEBS-SIS) for high-grip, cold-flex-resistant injection-molded shoe soles.
- The Custom TPE Compounding, Consumer Goods, Appliance, and Power-Tool Industry employs Thermoplastic Rubbers (SBS-SEBS-SIS) (specifically SEBS and SBS) to produce soft-touch overmolding pellets.
- The Automotive OEM Part, Extruded Weatherstrip, and Wire & Cable Jacketing Industry uses Thermoplastic Rubbers (SBS-SEBS-SIS) (specifically UV- and heat-stable SEBS) for weather-resistant seals and flexible cable insulation.
- The Medical Device, Pharmaceutical Packaging, Plastics Modification, and Polymer Recycling Industry utilizes high-purity Thermoplastic Rubbers (SBS-SEBS-SIS) for PVC-free medical tubing/stoppers and polyolefin/styrenic impact toughening.

USE OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) IN BITUMEN MODIFICATION (PMB & ROOFING) AND FOOTWEAR COMPOUNDS (TPR)

- Polymer-Modified Bitumen (PMB) for Road Paving and SBS Waterproofing Membranes with Thermoplastic Rubbers (SBS-SEBS-SIS): In road paving PMB (meeting EN 14023 and AASHTO M 320 Superpave PG 76-22 or PG 82-28 standards), 3.0% to 5.5% w/w of porous Radial or Linear SBS (30% styrene, Mw 130,000 to 320,000 g/mol) is milled into penetration-grade bitumen (such as 50/70 or 70/100 pen) at 175 to 185 °C using a high-shear rotor-stator colloid mill (often cross-linked in situ with 0.05% to 0.15% w/w elemental sulfur or functional polysulfide stabilizer to prevent hot-storage phase separation). In waterproofing roofing membranes (EN 13707 torch-on and self-adhesive SBS membranes reinforced with polyester/fiberglass mats), 10.0% to 14.0% w/w Radial/Linear SBS is blended with bitumen and 25%–35% limestone filler, raising the Ring-and-Ball Softening Point from ~48 °C up to +115 to +130 °C while depressing the cold mandrel flexibility temperature down to -20 to -25 °C!
- TPR Footwear Outsole Compounding with Thermoplastic Rubbers (SBS-SEBS-SIS): In injection-molded TPR shoe soles, compounders blend 100 parts of Linear or Oil-Extended SBS (30% to 40% styrene) with 15 to 40 phr naphthenic/paraffinic process oil, 10 to 30 phr Polystyrene (GPPS or HIPS) or EVA to adjust Shore A hardness (50 to 80 Shore A), 15 to 40 phr precipitated silica or calcium carbonate filler, and 0.5 phr phenolic/phosphite antioxidants.

USE OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) IN HOT-MELT ADHESIVES (HMPSA) AND SOFT-TOUCH TPE-S OVERMOLDING

- Hot-Melt Pressure-Sensitive Adhesives (HMPSA) with Thermoplastic Rubbers (SBS-SEBS-SIS):
  - SIS-Based HMPSAs (Tapes, Labels, and Diaper Construction): Low-styrene SIS grades (15%–18% styrene, containing 15%–40% SI diblock) are compounded at 100 parts polymer with 90 to 140 phr of aliphatic C5 hydrocarbon resin or hydrogenated rosin ester (which selectively tackifies the polyisoprene mid-block), 15 to 40 phr naphthenic/paraffinic plasticizer oil, and 1 to 2 phr hindered phenolic antioxidant at 150–170 °C under nitrogen. For high-shear packaging tapes and elastic diaper waistbands, low-diblock (< 1% diblock), higher-styrene (22%–30% styrene) SIS or SBS grades are used.
  - SEBS-Based Clear & UV-Stable HMPSAs: Hydrogenated SEBS compounded with water-white hydrogenated hydrocarbon resins (such as Arkon or Regalite) and white mineral oil produces crystal-clear, non-yellowing hot-melt adhesives for clear bottle labels, medical tapes, and automotive interior assembly.
- Soft-Touch TPE-S Compounding and Overmolding with Thermoplastic Rubbers (SBS-SEBS-SIS): High-molecular-weight porous SEBS powder (30% styrene, Mw ~220,000–280,000 g/mol) is pre-mixed in a high-intensity Henschel mixer with 80 to 200 phr of USP-grade paraffinic white mineral oil (until all oil is absorbed into a dry free-flowing powder), then compounded in a co-rotating twin-screw extruder at 190 to 220 °C with 20 to 60 phr Homopolymer or Random Copolymer Polypropylene (PP, which forms the continuous thermoplastic co-matrix that controls high-temperature compression set and bonds directly to rigid PP substrates during 2K injection overmolding!) plus 20 to 80 phr calcium carbonate or talc filler.

FORMULATION AND PROCESS CONSIDERATIONS WHEN USING THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

 Selecting the Correct Process Oil Type (Paraffinic vs. Naphthenic vs. Aromatic):
The single most critical compounding rule for Thermoplastic Rubbers (SBS-SEBS-SIS) is keeping the aromatic content of plasticizer oils as low as possible (< 1% to 3% CA aromatic carbons):
- Why Aromatic Oils Ruin SBS/SEBS/SIS Strength: If an oil contains significant aromatic hydrocarbons (such as DAE or TDAE aromatic oils), those aromatic molecules dissolve into the glassy Polystyrene end-blocks ("A" domains), plasticizing and lowering the Tg of the polystyrene physical crosslinks below 60 °C—which destroys tensile strength, causes severe compression set, and collapses adhesive shear holding power!
- Correct Oil Selection: For SEBS compounds, always use 100% saturated Paraffinic White Mineral Oil (kinematic viscosity >= 68 to 100 cSt at 40 °C), which is 100% compatible with the saturated ethylene-butylene mid-block and 0% soluble in the polystyrene domains. For SBS and SIS compounds, use low-aromatic Naphthenic Oil or Naphthenic/Paraffinic blends (aromatic carbon CA < 2%).

 Preventing Thermal-Oxidative Degradation During Melt Processing and Hot-Melt Mixing:
- Unsaturated SBS and SIS grades contain allylic C=C double bonds: during hot-melt adhesive mixing or twin-screw extrusion, keep melt temperatures strictly between 150 and 185 °C (never exceeding 195–200 °C for prolonged residence times), blanket hot-melt adhesive kettles with nitrogen gas, and always include 0.5% to 1.5% w/w of a primary + secondary antioxidant package (e.g., Irganox 1010 or 1076 + Irgafos 168; note that in pyrolysis/overheating, SBS crosslinks and gels to increase viscosity, whereas SIS undergoes chain scission and drops in viscosity!).
- Saturated SEBS grades are thermally stable up to 240 to 260 °C, allowing high-shear twin-screw compounding and co-injection overmolding at 200 to 240 °C.

TYPICAL USE LEVELS AND INITIAL FORMULATION APPROACHES FOR THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

Typical commercial incorporation levels for Thermoplastic Rubbers (SBS-SEBS-SIS) depend on the target application:
- Polymer-Modified Bitumen (PMB) for Highway Asphalt Paving (EN 14023 / Superpave PG Grades): Radial or Linear SBS (30% styrene, porous crumb) is incorporated at 3.0% to 5.5% w/w on bitumen weight (typically 3.8% to 4.5% w/w).
- SBS Waterproofing Roofing Membranes (Torch-On & Self-Adhesive Rolls): Radial and/or Linear SBS is dosed at 9.0% to 14.0% w/w of the total filled bituminous coating compound.
- Hot-Melt Pressure-Sensitive Adhesives (HMPSA for Tapes, Labels & Hygiene): SIS, SBS, or SEBS is incorporated at 20.0% to 45.0% w/w of the total adhesive formulation (paired with 40%–55% tackifying resin, 10%–25% plasticizing oil, and 1% antioxidant).
- Solvent-Borne Contact & Spray Adhesives (Footwear, Upholstery, Foam Bonding): Linear SBS (30%–40% styrene) is dissolved at 15.0% to 30.0% w/w in hydrocarbon/ester/ketone solvent blends with 10%–20% tackifier resin.
- TPR Footwear Outsole & Unit Sole Compounds: Dry or Oil-Extended SBS is compounded at 35.0% to 65.0% w/w of the total compound (100 phr SBS + 25–45 phr process oil + 15–30 phr PS/EVA + 20–40 phr filler).
- Soft-Touch TPE-S Overmolding, Automotive Seal, and Medical Tubing Compounds: Hydrogenated SEBS is compounded at 20.0% to 45.0% w/w (100 phr SEBS + 80–180 phr white paraffinic oil + 25–60 phr Polypropylene + 0–60 phr filler).
- Impact Modification of GPPS, HIPS, PP, and HDPE Plastics: SBS or SEBS is dry-blended at 4.0% to 15.0% w/w into the host thermoplastic resin.
The four laboratory and pilot frameworks below illustrate preliminary R&D evaluation protocols for qualified technical personnel formulating with Thermoplastic Rubbers (SBS-SEBS-SIS).

EXAMPLE 1: PREPARATION AND RHEOLOGICAL EVALUATION OF AN SBS-MODIFIED WATERPROOFING ROOFING MEMBRANE BITUMEN COMPOUND (-25 °C COLD BEND)

Purpose: To formulate an elastomeric SBS-modified bitumen coating mass for a 4.0 mm torch-on roofing waterproofing membrane using porous Radial SBS from the Thermoplastic Rubbers (SBS-SEBS-SIS) portfolio, and evaluate Ring-and-Ball Softening Point (EN 1427), Penetration at 25 °C (EN 1426), Elastic Recovery (EN 13398), and Cold-Bend Flexibility at -25 °C (EN 1109).
Initial pilot roofing compound formulation (per 1,000.0 g batch):
- Penetration-Grade Distillation Bitumen (160/220 pen or 70/100 pen with high aromatic maltene fraction): 570.0 g (57.0% w/w)
- Naphthenic Aromatic-Rich Bitumen Compatibilizer Flux Oil (if needed to boost maltene swelling): 20.0 g (2.0% w/w)
- Radial (4-Arm Star) SBS Thermoplastic Rubber (CAS 9003-55-8, Ataman Kimya Bitumen-Grade Porous Crumb from Thermoplastic Rubbers (SBS-SEBS-SIS), 30.0% w/w styrene, 70.0% w/w butadiene, Mw ~280,000 g/mol, MFR < 0.5 g/10 min): 110.0 g (11.0% w/w on total filled compound; 15.7% w/w on unfilled bitumen phase)
- Fine Ground Limestone / Calcium Carbonate Filler (d50 = 15 microns, < 90 microns): 298.5 g (29.85% w/w)
- Hindered Phenolic Thermal Antioxidant (Irganox 1010 / 1076): 1.5 g (0.15% w/w)
Laboratory evaluation procedure:
- Stage 1 (High-Shear SBS Swelling and Phase Inversion at 180 °C): Heat the 570.0 g bitumen and 20.0 g flux oil to 180 +/- 3 °C in a thermostated oil-jacketed stainless-steel vessel. Gradually feed in the 110.0 g porous Radial SBS crumb and 1.5 g antioxidant over 15 minutes under a high-shear Silverson rotor-stator homogenizer running at 4,500 rpm. Continue high-shear milling at 180–185 °C for 60 to 90 minutes while monitoring polymer dispersion under a UV fluorescence microscope (365 nm excitation): verify complete disappearance of discrete SBS particles and complete phase inversion into a continuous golden-yellow fluorescent SBS elastomer network swollen with bitumen maltenes!
- Stage 2 (Filler Incorporation and Membrane Sheet Casting): Switch to a low-shear anchor/paddle mixer (300 rpm at 180 °C), gradually blend in the 298.5 g pre-dried limestone filler over 30 minutes to degas and homogenize, and cast 4.0 mm thick sheets onto silicone release paper reinforced with a 180 g/m2 non-woven polyester mat.
- Stage 3 (EN 13707 Bitumen & Membrane Performance Testing): Verify Brookfield viscosity at 180 °C (target 3,500 to 5,500 mPa·s), Ring-and-Ball Softening Point on the unfilled PMB binder >= 122 °C (EN 1427, up from 44 °C for neat bitumen!), Needle Penetration at 25 °C = 35 to 45 dmm (EN 1426), Elastic Recovery at 25 °C >= 92% (EN 13398), High-Temperature Flow Resistance on vertical tiles >= 110 °C (EN 1110), and 100% crack-free pass on the -25 °C Cold-Bend Mandrel Flexibility test (EN 1109, both initial and after 28 days thermal aging at 70 °C).

EXAMPLE 2: TWIN-SCREW COMPOUNDING OF A SHORE A 45 SOFT-TOUCH SEBS OVERMOLDING TPE-S COMPOUND FOR POLYPROPYLENE SUBSTRATES

Purpose: To compound a non-bleeding, UV-stable, Shore A 45 soft-touch thermoplastic elastomer (TPE-S) using high-molecular-weight hydrogenated SEBS from the Thermoplastic Rubbers (SBS-SEBS-SIS) family, paraffinic white oil, and polypropylene, and evaluate mechanical properties and 2K overmold peel adhesion onto rigid Polypropylene.
Initial TPE-S compound formulation (expressed in parts per hundred SEBS rubber, phr, and % w/w):
- High-Molecular-Weight Porous SEBS Powder (CAS 66070-58-4, Ataman Kimya Compounding-Grade SEBS from Thermoplastic Rubbers (SBS-SEBS-SIS), 31.0% styrene / 69.0% ethylene-butylene, Mw ~240,000 g/mol, >= 99% hydrogenated): 100.0 phr (30.12% w/w)
- USP / Technical White Paraffinic Mineral Oil (CAS 8042-47-5, kinematic viscosity 95 cSt at 40 °C, 0.0% aromatic carbon, water-white): 130.0 phr (39.16% w/w)
- Homopolymer Polypropylene (PP, MFR = 12 g/10 min at 230 °C / 2.16 kg, thermoplastic co-continuous hard phase): 40.0 phr (12.05% w/w)
- Fine Uncoated Calcium Carbonate (d50 = 2.5 microns, whiteness >= 96%): 60.0 phr (18.07% w/w)
- Primary Hindered Phenol (Irganox 1010) + Secondary Phosphite (Irgafos 168) + HALS (Tinuvin 770) Stabilizer Package: 1.5 phr (0.45% w/w)
- Erucamide / Calcium Stearate Mold-Release Processing Aid: 0.5 phr (0.15% w/w; Total batch = 332.0 phr = 100.0% w/w)
Laboratory evaluation procedure:
- Stage 1 (Dry-Liquid Oil Absorption Pre-Blending): Charge the 100.0 phr porous SEBS powder into a high-speed ribbon or Henschel mixer at 25 °C and spray in the 130.0 phr paraffinic white mineral oil over 8 minutes at medium speed. Allow to tumble for 10 minutes until the porous SEBS crumbs absorb 100% of the oil into their internal ethylene-butylene mesopores, yielding a completely dry, free-flowing oil-extended SEBS powder! Add the 40.0 phr PP pellets, 60.0 phr CaCO3, 1.5 phr stabilizers, and 0.5 phr processing aid and blend for 3 minutes.
- Stage 2 (Co-Rotating Twin-Screw Extrusion Compounding): Feed the dry pre-blend into a co-rotating intermeshing twin-screw extruder (L/D = 40:1, screw speed 350 rpm) with barrel zones set from 180 °C (feed throat) to 205–215 °C (kneading/mixing blocks) and 210 °C (die head), equipped with a vacuum vent at Zone 8 and underwater or strand pelletizing.
- Stage 3 (Injection Overmolding and Mechanical Testing): Injection-mold 2.0 mm test plaques at 205 °C melt temperature (mold temperature 35 °C) and also overmold a 2.0 mm layer of the SEBS TPE-S compound directly onto a rigid 3.0 mm Homopolymer Polypropylene plaque in a two-shot mold. Condition for 24 hours at 23 °C and verify: Hardness = 45 +/- 2 Shore A (ISO 868), Specific Gravity = 0.99 g/cm3, Tensile Strength >= 6.8 MPa, Elongation at Break >= 680% (ISO 37), Tear Strength >= 28 kN/m, Compression Set (22 h at 70 °C, ISO 815) <= 28%, zero oil exudation after 7 days at 80 °C, and 90-degree peel bond strength to rigid PP substrate >= 65 N/25 mm (cohesive tearing inside the TPE layer!).

EXAMPLE 3: FORMULATION OF A HIGH-TACK, HIGH-SHEAR HOT-MELT PRESSURE-SENSITIVE ADHESIVE (HMPSA) FOR PACKAGING TAPES & LABELS USING SIS

Purpose: To formulate a 100%-solids Hot-Melt Pressure-Sensitive Adhesive (HMPSA) based on linear SIS from the Thermoplastic Rubbers (SBS-SEBS-SIS) range, and evaluate 175 °C Brookfield melt viscosity, Rolling-Ball Tack (PSTC-6), Loop Tack (PSTC-16), 180° Peel Adhesion to stainless steel and cardboard (PSTC-101), and Shear Holding Power / SAFT (PSTC-107).
Initial HMPSA formulation (per 1,000.0 g batch):
- Linear SIS Thermoplastic Rubber (CAS 25038-32-8, Ataman Kimya Adhesive-Grade SIS from Thermoplastic Rubbers (SBS-SEBS-SIS), 16.0% to 18.0% w/w styrene, ~18% SI diblock content, MFR = 11 g/10 min at 200 °C/5 kg, Vector 4113 / Kraton D1161 equivalent): 320.0 g (32.0% w/w)
- Aliphatic C5 / Aromatically-Modified C5/C9 Hydrocarbon Tackifying Resin (Ring-and-Ball Softening Point = 98 °C, Gardner color <= 3, selectively compatible with the polyisoprene mid-block): 510.0 g (51.0% w/w)
- Low-Volatility Naphthenic / Paraffinic Process Oil (aromatic carbon < 1%, pour point -25 °C, viscosity Depressant and glass-transition lowerer): 160.0 g (16.0% w/w)
- Phenolic + Thioester / Phosphite Thermal Antioxidant Package (Irganox 1010 + Irganox PS 800 / Irgafos 168, mandatory to prevent polyisoprene chain scission during hot-melt compounding!): 10.0 g (1.0% w/w)
Laboratory evaluation procedure:
- Charge the 320.0 g SIS pellets, 10.0 g antioxidant package, and 250.0 g (half) of the C5 hydrocarbon tackifier resin into a nitrogen-blanketed sigma-blade Z-arm kneader or vertical high-shear hot-melt mixer preheated to 165 °C. Masticate under nitrogen for 25 minutes until the high-shear mixing melts and homogenizes the SIS polymer completely into the molten resin without unmelted gel specks.
- Gradually add the remaining 260.0 g C5 tackifying resin and 160.0 g process oil over 20 minutes at 160 to 165 °C and mix for a final 15 minutes until a crystal-clear, golden homogeneous liquid is obtained.
- Measure Brookfield Thermosel viscosity at 175 °C (Spindle No. 27: target 6,500 to 9,500 mPa·s, ideal for high-speed slot-die coating). Coat the molten HMPSA at 25 +/- 2 g/m2 coat weight onto 23-micron corona-treated BOPP film (for packaging tape) and 60 g/m2 siliconized release liner / paper facestock (for labels).
- Condition coated tapes at 23 °C / 50% RH for 24 hours and verify: Rolling-Ball Tack (PSTC-6) <= 2.5 cm, Loop Tack on stainless steel (PSTC-16) >= 24 N/25 mm, 180-degree Peel Adhesion on stainless steel (PSTC-101) >= 18 N/25 mm (with clean corrugated cardboard fiber tear!), Static Shear Holding Time on steel (25 x 25 mm x 1.0 kg load at 23 °C, PSTC-107) > 10,000 minutes, and Shear Adhesion Failure Temperature (SAFT, 0.5 kg load ramped at 0.5 °C/min) >= 84 °C.

EXAMPLE 4: TPR FOOTWEAR OUTSOLE COMPOUNDING WITH OIL-EXTENDED SBS, POLYSTYRENE AND SILICA FOR SUB-ZERO FLEX RESISTANCE

Purpose: To formulate an abrasion-resistant, non-slip Shore A 62 Thermoplastic Rubber (TPR) footwear outsole compound using Oil-Extended SBS and High-Styrene Dry SBS from the Thermoplastic Rubbers (SBS-SEBS-SIS) portfolio, and evaluate Ross Flex-Crack Resistance at -20 °C (ASTM D1052) and DIN Abrasion Loss (ISO 4649).
Initial TPR shoe-sole formulation (expressed in parts per hundred total SBS rubber, phr):
- Oil-Extended Radial/Linear SBS (CAS 9003-55-8, Ataman Kimya Footwear Grade from Thermoplastic Rubbers (SBS-SEBS-SIS), 30% styrene base polymer pre-extended with 37.5 phr paraffinic/naphthenic oil = 72.7% rubber + 27.3% oil): 80.0 phr
- Dry High-Styrene Linear SBS (40% styrene / 60% butadiene, MFR = 6 g/10 min, hardness and melt-flow enhancer): 20.0 phr
- High-Impact Polystyrene (HIPS) or General-Purpose Polystyrene (GPPS, polystyrenic domain hardener): 15.0 phr
- Ethylene-Vinyl Acetate Copolymer (EVA, 18% VA content, MFR 2.5, abrasion and surface feel improver): 10.0 phr
- Additional Naphthenic Process Oil (flow & softness adjuster): 12.0 phr
- Precipitated Hydrated Amorphous Silica (BET surface area 160 m2/g, reinforcing non-black filler for translucent/colored soles) + Calcium Carbonate: 15.0 phr Silica + 15.0 phr CaCO3
- Zinc Stearate + Stearic Acid (internal lubricant / mold release) + Phenolic/Phosphite Antioxidant + UV Absorber: 2.5 phr (Total batch = 169.5 phr)
Laboratory evaluation procedure:
- Pre-blend all components in a tumble mixer for 5 minutes, compound in a Banbury internal mixer (dump temperature 155 °C) or twin-screw extruder (160–175 °C), and pelletize.
- Injection-mold 6.0 mm footwear test soles at 170 to 180 °C nozzle temperature (mold temperature 25 °C; cycle time 22 seconds).
- Condition for 24 hours at 23 °C and test per footwear standards: confirm Hardness = 62 +/- 2 Shore A, Specific Gravity = 0.99 g/cm3, Tensile Strength >= 9.5 MPa, Elongation at Break >= 580%, DIN Abrasion Volume Loss (ISO 4649, 10 N load) <= 135 mm3, Wet Dynamic Coefficient of Friction on quarry tile >= 0.55, and Ross Flex-Crack Resistance at -20 °C (ASTM D1052, pierced specimen) > 100,000 cycles with zero crack propagation!

COMPATIBILITY AND INCOMPATIBILITY OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

- Compatible Polymers, Resins, Oils, and Fillers:
  - Compatible Thermoplastics: Polystyrene (GPPS, HIPS, SAN) is 100% compatible with the polystyrene end-blocks of SBS, SEBS, and SIS. Polypropylene (PP), Polyethylene (LDPE, LLDPE, HDPE), Ethylene-Vinyl Acetate (EVA), and Polybutene-1 are highly compatible with SEBS and SBS (forming co-continuous TPE-S networks). Polyphenylene Ether (PPE / PPO) is miscible in all proportions with the polystyrene end-blocks to raise high-temperature compression set resistance above 120 °C!
  - Compatible Plasticizer Oils: Paraffinic white mineral oils and low-aromatic naphthenic oils (CA < 2%), polybutene / polyisobutylene (PIB) liquid polymers.
  - Compatible Tackifying Resins: Aliphatic C5 hydrocarbon resins, DCPD resins, hydrogenated C5/C9 resins, polyterpene resins, and pentaerythritol/glycerol rosin esters (mid-block compatible); aromatic C9, coumarone-indene, and alpha-methylstyrene resins (polystyrene end-block compatible).
  - Compatible Fillers: Calcium carbonate (CaCO3), talc, kaolin clay, precipitated/fumed silica, barite, carbon black, and halogen-free flame retardants (ATH, MDH, APP).

- Chemical and Material Incompatibilities:
  - High-Aromatic Oils & Solvents in Compounding: High-aromatic oils (DAE, TDAE) and aromatic/chlorinated solvents solvate and soften the glassy polystyrene end-block domains, destroying the physical crosslinking network at room temperature.
  - Unmodified Polar Engineering Plastics (PA, PC, ABS, PET, TPU): Standard non-polar SBS, SEBS, and SIS do not adhere directly to polar Polyamide (Nylon), Polycarbonate, or ABS in 2K overmolding unless maleated SEBS (SEBS-g-MAH, 1%–2% grafted maleic anhydride) or a TPU/copolyester compatibilizer is incorporated into the TPE-S compound.
  - Strong Oxidizing Agents, Halogens, and Concentrated Nitric/Sulfuric Acids: Attack the polymer backbone (especially unsaturated SBS and SIS).

SIMILAR PRODUCTS AND ALTERNATIVES TO THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

Polymer engineers compare the three members of Thermoplastic Rubbers (SBS-SEBS-SIS) against each other and against vulcanized rubbers and TPO/TPV elastomers:

THERMOPLASTIC RUBBERS: SBS (CAS 9003-55-8) AND SEBS (CAS 66070-58-4)

SBS has an unsaturated polybutadiene mid-block (Tg -90 °C), lower raw-material cost, faster dissolution in road/roofing bitumen, and superior solvent-adhesive tack, making SBS the undisputed leader in PMB asphalt, roofing membranes, and TPR shoe soles. SEBS is the selectively hydrogenated derivative of SBS (saturated ethylene-butylene mid-block, Tg -55 °C); SEBS costs more than SBS but delivers 10-fold higher UV, ozone, and 250 °C thermal stability, water-white transparency, and 200+ phr white-oil absorption—making SEBS mandatory for outdoor weatherseals, soft-touch PP overmolding, medical devices, and clear gels.

THERMOPLASTIC RUBBERS: SIS (CAS 25038-32-8) AND SBS IN HOT-MELT ADHESIVES

Because the polyisoprene mid-block of SIS has a much lower entanglement plateau modulus than the polybutadiene mid-block of SBS, SIS compounds with C5 tackifying resins to yield far higher loop tack, lower melt viscosity, and cleaner peel on paper, cardboard, and skin (making SIS the number-one choice for packaging tapes, labels, and diaper adhesives), whereas SBS provides higher cohesive shear strength and solvent solubility for construction mastics and footwear contact cements.

THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) AND TPO / TPV ELASTOMERS

Polyolefin elastomers (POE/TPO) lack the glassy +100 °C polystyrene anchor domains of SEBS, so TPOs suffer from poor elastic recovery and high tension/compression set. Thermoplastic Vulcanizates (TPV, dynamically vulcanized EPDM/PP blends) offer higher hot-oil resistance in automotive under-hood hoses, but TPVs are opaque/brownish, cannot be formulated below ~Shore A 35, and cannot match the ultra-soft feel (Shore OO 15 to Shore A 30), water-white colorability, or adhesive tack of Thermoplastic Rubbers (SBS-SEBS-SIS).

QUALITY GRADES, QUALITY CONTROL AND PURCHASING CRITERIA FOR THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

Ataman Kimya supplies a comprehensive matrix of grades across all three families of Thermoplastic Rubbers (SBS-SEBS-SIS):
 SBS Grades (CAS 9003-55-8):
- Road Paving & Roofing Bitumen Grades (Porous Crumb / Powder): Linear 30% Styrene (1301 type, MFR < 1 g/10 min) and Radial 4-Arm Star 30% Styrene (1401 / 4303 type, Mw ~280,000–350,000 g/mol, MFR < 0.5 g/10 min) for fast bitumen swelling and high softening point.
- Footwear (TPR) & Compounding Grades (Dense Pellets): Dry Linear 30% & 40% Styrene grades (MFR 3 to 15 g/10 min) and Oil-Extended SBS grades (containing 30 to 50 phr paraffinic/naphthenic oil).
- Adhesive & Plastic Impact-Modification Grades: Medium-viscosity, low-ash, non-staining linear and radial SBS grades.

 SEBS Grades (CAS 66070-58-4):
- High-Molecular-Weight Porous Compounding Powder (G1651 type, ~31%–33% Styrene, Mw > 220,000 g/mol, MFR < 1 g/10 min): Absorbs up to 200–300 phr white oil for soft-touch TPE overmolding, medical tubing, and automotive extrusions.
- Medium- & Low-Molecular-Weight Pellet/Powder Grades (G1650 / G1652 type, 29%–30% Styrene, MFR 5–25 g/10 min): Designed for UV-stable hot-melt adhesives, sealants, oil gels, and engineering plastic impact modification.
- Maleic Anhydride Grafted SEBS (SEBS-g-MAH, 1.0%–1.8% MAH): Polar-functionalized SEBS for overmolding onto PA (Nylon), PC, ABS, and PET, and for toughening Nylon 6 / Nylon 66.

 SIS Grades (CAS 25038-32-8):
- Low-Styrene, Medium/High-Diblock Tape & Hygiene Grades (15%–18% Styrene, 18%–40% SI diblock, MFR 8–18 g/10 min): Maximum loop tack and low melt viscosity for BOPP tapes, labels, and diaper construction.
- Medium/High-Styrene Pure Triblock High-Cohesion Grades (18%–30% Styrene, < 1% diblock, Vector 4111A / 4211A equivalents): Maximum shear holding power and elasticity for elastic diaper attachments and specialty tapes.

STORAGE AND HANDLING OF THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

- Commercial Packaging Formats from Ataman Kimya:
  - 15 kg, 20 kg, or 25 kg multi-wall kraft paper, woven polypropylene, or low-melting EVA/PE inclusion bags (which can be thrown unopened directly into hot bitumen mixers or Banbury kneaders!), palletized and stretch-wrapped (typically 800 to 1,000 kg per pallet).
  - 450 kg to 900 kg Flexible Intermediate Bulk Containers (FIBC / Big Bags with anti-static inner liner and bottom discharge spout) for high-volume asphalt PMB plants, roofing mills, and TPE compounding lines.
- Mandatory Warehouse Storage and Handling Precautions:
  - Store Thermoplastic Rubbers (SBS-SEBS-SIS) in a cool, dry, clean, well-ventilated indoor warehouse at ambient temperatures below +30 to +35 °C, away from direct sunlight (UV radiation rapidly crosslinks and yellows exposed bags of unsaturated SBS and SIS!), ozone-generating electrical equipment (motors, arc welders), heaters, moisture, and strong oxidizing agents.

  - Prevent Pellet Blocking / Caking: Avoid stacking pallets more than 2 high in warm summer warehouses (> 35 °C), particularly for soft low-styrene SIS and oil-extended SBS grades, as excessive compressive load + heat can cause pellets to sinter ("block") together.
  - Slip and Static-Electricity Dust Hazards: Spilled pellets or crumbs on warehouse floors create an immediate slipping hazard and must be swept or vacuumed up promptly. When pneumatically conveying porous SEBS or SBS powder/crumb into silos or mixers, ground and bond all metal hoppers, pipes, and FIBC bags to prevent static spark discharges in airborne polymer dust clouds.
  - Shelf Life: 12 to 24 months for unsaturated SBS and SIS grades when stored unopened in dark, cool (< 30 °C) indoor conditions; 36+ months for saturated hydrogenated SEBS grades.
- Transport Classification (ADR / RID / ADN / IMDG / IATA-DGR):
  - UN Number: Not regulated as dangerous goods for transport (Non-Hazardous Solid Polymer Cargo under ADR, RID, IMDG Code, and IATA).
  - Marine Pollutant (IMDG): No.

FIRST AID MEASURES AND SAFETY INFORMATION FOR THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

- Toxicological and Workplace Hygiene Profile:
  - Solid Polymer Inertness: At ambient temperatures, solid pellets, crumbs, and powders of Thermoplastic Rubbers (SBS-SEBS-SIS) are chemically inert, water-insoluble, non-toxic, and non-irritating to skin (many pure grades comply with US FDA 21 CFR 177.1810 food-contact and USP Class VI medical biocompatibility standards).
  - Hot Melt Processing Fumes & Thermal Burn Hazards: During high-temperature extrusion, injection molding, hot-melt adhesive mixing (150 to 240 °C), or bitumen milling (180 °C), molten polymer causes severe thermal skin burns upon contact (never attempt to peel solidified hot polymer off burned skin!). Furthermore, overheating above 220–250 °C evolves irritating thermal degradation vapors/fumes containing trace styrene, butadiene/isoprene oligomers, aldehydes, ketones, and carbon monoxide; always provide local exhaust ventilation canopy hoods over extruder dies, Banbury dumps, and hot-melt tanks.
  - Dust Control: Avoid inhaling airborne polymer dust or anti-blocking dusting agents (amorphous silica, talc, calcium stearate) when dumping bags; maintain workplace dust below OSHA/ACGIH nuisance particulate limits (10 mg/m3 inhalable, 3 mg/m3 respirable).

- Fire-Fighting & Electrostatic Precautions:
  - Combustible solid thermoplastics: Keep away from open flames, welding sparks, and static discharges. In a fire, extinguish with water fog/spray, foam, dry chemical powder, or CO2; firefighters must wear positive-pressure Self-Contained Breathing Apparatus (SCBA).

- First Aid Measures:
  - Contact with Hot Molten Polymer: Immediately immerse or flush the affected skin with copious cold running water for at least 15 to 20 minutes to dissipate heat. Do NOT attempt to pull or peel solidified polymer off the skin (which tears underlying tissue); seek immediate medical attention for thermal burn treatment.
  - Inhalation of Processing Vapors or Dust: Move the person to fresh air; seek medical attention if respiratory irritation, coughing, or headache persists.
  - Eye Contact (Dust / Fines): Flush eyes with lukewarm running water for 10 to 15 minutes without rubbing.

WHAT SHOULD BE CONSIDERED WHEN PURCHASING THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)?

 Select the Correct Polymer Family (SBS vs. SEBS vs. SIS) Based on End-Use Environment and Chemistry: Specify SBS (CAS 9003-55-8) for road/roofing bitumen modification, TPR shoe soles, solvent adhesives, and HIPS impact modification; specify Hydrogenated SEBS (CAS 66070-58-4) whenever UV/ozone weatherability, water-white clarity, 220–260 °C thermal stability, or high white-oil absorption (soft-touch TPE overmolding and medical tubing) is required; specify SIS (CAS 25038-32-8) for high-tack hot-melt pressure-sensitive tapes, labels, and hygiene adhesives.
 Specify Linear (A-B-A) versus Radial / Star ((A-B)nX) Architecture and Physical Form: For Polymer-Modified Bitumen (PMB) and waterproofing membranes, specify Porous Crumb / Powder (for fast 60-minute bitumen swelling) in Radial SBS (for maximum softening point elevation and rutting resistance) or Linear SBS (for low viscosity and elastic recovery); for twin-screw extrusion and injection molding, specify Dense Pellets (or Porous High-MW SEBS Powder if pre-absorbing > 100 phr white oil).
 Verify Styrene Content (% w/w), Diblock Content (% w/w), and Melt Flow Rate (MFR) on the Certificate of Analysis: In SIS adhesives, choose 15%–18% styrene with 18%–40% SI diblock for maximum loop tack, or 22%–30% styrene with < 1% diblock for maximum shear creep resistance; in SBS footwear, choose 30% styrene for soft/cold-flex soles or 40% styrene for harder, high-flow soles.
 Confirm Non-Staining Antioxidant Package and Food/Medical Compliance: Ensure the grade is stabilized with non-staining hindered phenolic/phosphite antioxidants (BHT-free if required to prevent NOx gas yellowing in white textiles/hygiene products) and carries FDA 21 CFR or EU 10/2011 declarations where applicable.

THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) SUPPLY FROM ATAMAN KİMYA

Ataman Kimya supplies a complete, multi-grade portfolio of Thermoplastic Rubbers (SBS-SEBS-SIS)—covering Linear & Radial SBS (CAS 9003-55-8, dry and oil-extended, porous crumb and pellets), Hydrogenated SEBS & Maleated SEBS-g-MAH (CAS 66070-58-4, porous high-MW powder and pellets), and Low-/High-Diblock SIS (CAS 25038-32-8)—directly from warehouse stocks in Türkiye.
 Every shipment of Thermoplastic Rubbers (SBS-SEBS-SIS) from Ataman Kimya is accompanied by a lot-specific Certificate of Analysis (CoA) verifying styrene content, diblock percentage, solution viscosity or Melt Flow Rate (MFR), Shore A hardness, tensile properties, volatile matter, and ash content, alongside EU REACH / CLP and Turkish KKDIK compliant Safety Data Sheets.
 For Polymer-Modified Bitumen (PMB) and roofing membrane producers, Ataman Kimya delivers porous Radial and Linear SBS in low-melting EVA direct-inclusion bags and 500–900 kg Big Bags alongside sulfur crosslinkers, polyphosphoric acid (PPA), and bitumen adhesion promoters.
 For Hot-Melt Adhesive (HMPSA), Footwear (TPR), and Soft-Touch TPE-S compounders, Ataman Kimya offers SIS, SBS, and SEBS alongside C5/C9/Hydrogenated Hydrocarbon Tackifying Resins, Rosin Esters, Paraffinic White Mineral Oils, EVA Copolymers, Precipitated Silica, and Phenolic/Phosphite Antioxidants from a single integrated supply hub.
 Ataman Kimya's technical specialists assist R&D laboratories and plant engineers in selecting the optimal grade of Thermoplastic Rubbers (SBS-SEBS-SIS) and provide sample quantities for pilot trials.

FREQUENTLY ASKED QUESTIONS ABOUT THERMOPLASTIC RUBBERS (SBS-SEBS-SIS)

 How do Thermoplastic Rubbers (SBS-SEBS-SIS) behave like vulcanized rubber at room temperature without using sulfur vulcanization?
Thermoplastic Rubbers (SBS-SEBS-SIS) are A-B-A block copolymers with glassy Polystyrene end-blocks ("A", Tg ~ +100 °C) and rubbery elastomeric mid-blocks ("B", Tg ~ -55 to -90 °C). Below +90 °C, the incompatible polystyrene end-blocks phase-separate into rigid 20–30 nm nano-domains that act as physical crosslink junctions locking the rubber chains into an elastic network. When heated above 150 to 210 °C (or dissolved in solvents), the polystyrene domains soften and release the chains so the polymer melts and flows like a thermoplastic, then re-solidifies into an elastic rubber immediately upon cooling!

 What is the exact chemical difference between SBS, SEBS, and SIS?
All three have Polystyrene ("S") end-blocks, but differ in their central elastomeric mid-block:
- SBS (CAS 9003-55-8) has an unsaturated 1,3-polybutadiene ("B") mid-block (Tg ~ -90 °C)—best for road/roofing bitumen modification, TPR shoe soles, and contact adhesives.
- SEBS (CAS 66070-58-4) is catalytically hydrogenated SBS with a 100% saturated ethylene-butylene ("EB") mid-block (Tg ~ -55 °C, zero C=C double bonds)—best for UV/ozone-resistant outdoor parts, 220–260 °C soft-touch overmolding, clear gels, and medical tubing.
- SIS (CAS 25038-32-8) has an unsaturated cis-1,4-polyisoprene ("I") mid-block (Tg ~ -60 °C)—best for high-tack hot-melt pressure-sensitive adhesives (HMPSA) in tapes, labels, and baby diapers.

 What is the difference between Linear SBS and Radial (Star-Branched) SBS in bitumen modification (PMB)?
Linear SBS has a straight S-B-S three-block chain (Mw ~110,000–150,000 g/mol), giving lower bitumen viscosity and ultra-high elongation. Radial (Star-Branched) SBS has 3 or 4 S-B arms coupled around a central core (Mw ~250,000–350,000 g/mol). Because each Radial SBS molecule carries 4 polystyrene anchor blocks, it forms a stronger three-dimensional network in bitumen—raising the Ring-and-Ball Softening Point by 5 to 12 °C more than linear SBS and providing superior resistance to highway wheel-track rutting and roofing high-temperature flow.

 Why must Paraffinic White Oil (and never high-aromatic oil) be used when compounding SEBS?
In SEBS (and SBS/SIS), the mechanical strength of the rubber depends entirely on keeping the Polystyrene end-block domains glassy and rigid (Tg ~ +100 °C). Paraffinic white mineral oil (0% aromatic carbon) dissolves selectively into the rubbery ethylene-butylene mid-block to soften the TPE while leaving the polystyrene domains untouched. By contrast, aromatic oils dissolve into the polystyrene domains, plasticizing and weakening the physical crosslinks so the compound loses tensile strength and suffers severe permanent compression set!

 Why is Polypropylene (PP) always blended with SEBS and white oil in soft-touch TPE-S overmolding compounds?
When high-MW SEBS is extended with 100 to 200 phr of white mineral oil, the oil-swollen SEBS alone has a high melt viscosity and low tear/compression-set resistance above 70 °C. Blending 20 to 60 phr of Homopolymer or Copolymer Polypropylene (PP, melting point 145–165 °C) creates a co-continuous thermoplastic PP phase that slashes injection-molding melt viscosity, reinforces tear strength, improves 70–100 °C compression set, and enables direct thermal fusion bonding when overmolded onto rigid PP tool handles or toothbrush bodies!

 How does the SI Diblock content in SIS affect Hot-Melt Pressure-Sensitive Adhesive (HMPSA) performance?
In SIS block copolymers, pure S-I-S triblock chains have both ends locked into polystyrene domains, providing high cohesive shear strength and high temperature resistance (SAFT). Uncoupled S-I diblock chains have one free polyisoprene end that dangles freely; increasing the SI diblock content (from < 1% up to 18%–40%) lowers the hot-melt coating viscosity and boosts aggressive initial loop tack and peel adhesion on cardboard and skin.

 Why is Porous Crumb ("Fluffy Pellet") preferred over Dense Pellets for bitumen modification and oil absorption?
Porous crumb (produced by steam coagulation stripping) has an internal sponge-like porosity with a specific surface area 10 times higher than melt-extruded dense pellets. In 180 °C bitumen tanks, porous SBS crumb absorbs hot maltene oils and dissolves in 45 to 75 minutes (versus 3 to 4 hours for dense pellets); in SEBS compounding, porous high-MW SEBS powder absorbs up to 250 phr of cold white mineral oil in a ribbon blender to form a dry, free-flowing powder ready for twin-screw extrusion.

 Can SEBS TPE-S compounds be overmolded onto polar engineering plastics like ABS, Polycarbonate (PC), or Nylon (PA)?
Standard unmodified SEBS is non-polar and only bonds directly to non-polar polyolefins (PP and PE). However, by compounding SEBS with Maleic Anhydride Grafted SEBS (SEBS-g-MAH) and a polar compatibilizer (such as TPU, copolyester, or SAN/EVA), specialized adhesion-modified TPE-S compounds achieve strong chemical and mechanical peel adhesion onto ABS, PC, PC/ABS, PMMA, and Polyamide (Nylon 6 / 66).

 What happens if SBS or SIS is overheated above 200–220 °C during hot-melt mixing, and how do they degrade differently?
Because SBS and SIS contain unsaturated C=C double bonds in their mid-blocks, overheating in the presence of oxygen triggers free-radical degradation—but via opposite pathways: in SBS, polybutadiene radicals crosslink with adjacent chains, causing melt viscosity to spike and form unmeltable gel specks; in SIS, polyisoprene radicals undergo beta-scission cleavage, causing melt viscosity and cohesive shear strength to drop rapidly! Blanket hot-melt mixers with nitrogen, keep temperatures <= 175–185 °C, and include 0.5%–1.0% phenolic/phosphite antioxidants.

 Are Thermoplastic Rubbers (SBS-SEBS-SIS) recyclable and safe for food-contact or medical applications?
Yes. Because their crosslinking is 100% physical and reversible, all molding runners, extrusion trim, and post-industrial scrap from Thermoplastic Rubbers (SBS-SEBS-SIS) can be reground and reprocessed directly without property loss. Furthermore, non-staining grades of SEBS, SBS, and SIS are free of vulcanization curatives, nitrosamines, heavy metals, halogens, and phthalates, complying with US FDA 21 CFR and EU 10/2011 food-contact and USP Class VI medical requirements.

THERMOPLASTIC RUBBERS (SBS-SEBS-SIS) – TECHNICAL SUMMARY

Thermoplastic Rubbers (SBS-SEBS-SIS)—encompassing Styrene-Butadiene-Styrene (SBS, CAS 9003-55-8), Hydrogenated Styrene-Ethylene-Butylene-Styrene (SEBS, CAS 66070-58-4), and Styrene-Isoprene-Styrene (SIS, CAS 25038-32-8) Styrenic Block Copolymers (SBC / TPE-S / TPS)—deliver the definitive combination of vulcanized-rubber elasticity below +90 °C and reversible thermoplastic melt processability above +150 °C. Through tailored styrene contents (13% to 43% w/w), linear (A-B-A) and radial ((A-B)nX) architectures, controlled diblock ratios, and porous crumb, powder, or pellet morphologies, Thermoplastic Rubbers (SBS-SEBS-SIS) serve as the essential elastomeric polymers across Polymer-Modified Bitumen (PMB) Asphalt Highways, Torch-On & Self-Adhesive SBS Roofing Membranes, Hot-Melt Pressure-Sensitive Adhesives (HMPSA for Tapes, Labels & Hygiene), TPR Footwear Outsoles, UV/Ozone-Resistant Soft-Touch SEBS Overmolding Compounds, PVC-Free Medical Tubing & Stoppers, Halogen-Free Cable Jacketing, and Thermoplastic Impact Modification. For technical data sheets, grade cross-referencing, sample requests, or bulk bag and FIBC quotations for Thermoplastic Rubbers (SBS-SEBS-SIS), contact Ataman Kimya:

Ataman Chemicals
Phone: +90 216 577 10 10
Email: info@atamankimya.com