Sinopec YH-602T

Styrene Ethylene Butylene Styrene (SEBS) block copolymers are among the most versatile thermoplastic elastomers (TPEs) on the market. Produced by the selective hydrogenation of Styrene-Butadiene-Styrene (SBS), SEBS uniquely combines the processability of thermoplastics with the elasticity of vulcanized rubber. It is widely applied across medical devices, wire/cable insulation, overmolding, automotive parts, sealants, and footwear.    However, not all SEBS grades perform identically. The molecular architecture—such as linear vs. star-shaped structures, vinyl content (1,2-structure), and main-chain monomer distribution—significantly dictates processability, oil absorption, transparency, and mechanical strength.    1. Linear vs. Radial SEBS Standard SEBS usually has a styrene content of 30%–40%. In unfilled states, conventional SEBS exhibits low melt flow. To achieve melt processability, it is commonly extended with paraffin oil and modified with Polypropylene (PP).    Linear SEBS (such as Sinopec YH-503T): Provides higher tensile strength and modulus due to more physical entanglement points along the linear polymer chains. It is the preferred choice for structural applications requiring higher tensile performance.    Radial SEBS (such as Sinopec YH-602T): Features a multi-arm coupled structure with smaller relative arm molecular weight. This yields superior melt flowability, lower compression set, and better elasticity. It is ideal for high-elasticity applications like elastic bands, seal strips, and complex molded products.      2. High 1,2-Vinyl Content SEBS Conventional SEBS requires heavy paraffin oil extension for processing. However, oil bleed-out, surface tackiness, and volatile organic compound (VOC) emissions under extreme high/low temperature conditions limit its application in clean or extreme environments.    By increasing the 1,2-structure content of the pre-hydrogenated polybutadiene segment (>60%): The chain regularity of the resulting SEBS is disrupted, which lowers melt viscosity.    Direct Processing without Oil: Exhibit high melt flow rates without oil addition.    Clean & Low-Odor Applications: Perfect for oil-free medical devices, surgical/protective clothing, film materials, automotive interior components, and transparent PP toughening agents.      3. Random Mid-Block Copolymerization Introducing styrene randomly into the middle butadiene block creates a unique middle-chain random copolymer structure.    Enhanced Transparency: The random dispersion of styrene interrupts polyethylene crystallization, yielding high optical clarity (light transmittance up to 88%).    Filler Compatibility & Processing Aid: This structure increases polymer polarity, improving compatibility with inorganic fillers (CaCO3) and polar resins. When blended with standard SEBS, it acts as an effective processing promoter and surface quality enhancer.    Damping Performance: Reduces elastic modulus and increases damping properties, making it suitable for shock-absorbing applications such as athletic tracks and suspended flooring mats.   4. Hydrogenated Styrene-Butadiene Random Copolymers For modified EVA foaming applications (e.g., shoe soles, footwear midsoles), standard oil-extended SEBS often causes increased compression set and thermal shrinkage due to oil migration.    Hydrogenated styrene-butadiene random copolymers without terminal polystyrene block segments can be directly blended with EVA without oil extension: Improved Resilience & Low Shrinkage: Blending SEBS into EVA foam formulations significantly increases rebound resilience (up to 58%) while noticeably reducing compression set and thermal shrinkage.    Dimensional Stability: Ensures lightweight, soft, and dimensionally stable foam products with excellent tactile feel.      Summary & Product Selection Matrix SEBS Structural Feature Advantages Applications Linear Structure High tensile strength, good mechanical integrity Structural parts, high-strength TPE compounds Radial Structure High elasticity, low compression set, superior melt flow Seal strips, elastic bands, complex injection molding High 1,2-Vinyl Content Processable without oil, zero oil bleed-out, low odor Medical devices, transparent PP toughening, protective wear Random Mid-Block Styrene High transparency, high polar filler compatibility, damping Clear TPEs, high-filler Masterbatches, vibration damping pads Non-Block Hydrogenated Random Copolymer Direct EVA blending without oil, high resilience, low shrinkage Premium footwear midsoles, athletic shoe soles, foam mats   Website: www.elephchem.com whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com