In high-temperature vulcanized (HTV) raw rubber synthesis, addition-cure liquid silicone rubber (LSR), silicone gel, and polyurethane/acrylic modification, the controllability of molecular weight and reactivity of active intermediates directly determine the processing performance, crosslinking density, and mechanical ceiling of final materials. While traditional vinyl double-head caps are mature chain-end introducers, their small-molecule nature results in coarse molecular chain regulation and narrow process windows during raw rubber polymerization; whereas conventional vinyl-terminated silicone oils (viscosity ranging from hundreds to tens of thousands cSt) suffer from uneven dispersion, high mixing energy consumption, and insufficient reactivity release in low-hardness silicone rubber, precision potting, and highly-filled compounding scenarios. With escalating demands for "low polymerization degree, dual-end vinyl, 10-20mPa·s ultra-low viscosity, volatile matter ≤0.1%, capable of replacing vinyl double-head caps" active intermediates, sourcing a key prepolymer with "ethoxy-terminated small-molecule linear polydimethylsiloxane, easy hydrolytic crosslinking with ethanol generation, dual-end vinyl high reactivity" has become the core gap for domestic high-end silicone rubber and polymer modification localization. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches IOTA 218 Low-Viscosity Vinyl Silicone Oil (Chemical Name: vinyl-terminated ethylene-dimethylsiloxane copolymer, i.e., ethoxy-terminated small-molecule linear polydimethylsiloxane; CAS 26710-23-6). Characterized by "colorless transparent liquid; viscosity 10-20mPa·s (20℃); flash point ≥61℃; volatile matter (105℃/2h) ≤0.1%; IBC ton drum (1000kg)/200L iron or plastic drum (200kg)/25L plastic drum (25kg) and customized packaging; non-hazardous chemical storage and transport; original packaging shelf life 1 year", backed by "ethoxy-terminated small-molecule linear skeleton + dual-end vinyl high reactivity + 10-20mPa·s ultra-low viscosity + easy hydrolytic crosslinking with ethanol for in-situ curing", it serves as the "active engine" for HTV raw rubber, addition-cure LSR, silicone gel, and polymer modification, capable of replacing traditional vinyl double-head caps as raw rubber prepolymer, providing more flexible molecular structure control and more optimized process parameters. Molecular Architecture: Ethoxy-Terminated Small Molecule + Dual-End Vinyl High Reactivity + Si-O-Si Low-Polymer Skeleton

• Ethoxy Terminus Easy Hydrolytic Crosslinking: The molecular chain ends are ethoxy groups (EtO-), which readily undergo hydrolytic condensation upon contact with water, releasing ethanol — this characteristic enables its use as an "in-situ crosslinking agent" in specific application scenarios, while simultaneously providing a reactive interface for further functionalization of the molecular chain.
• Dual-End Vinyl High Reactivity: Both ends of the molecular chain carry vinyl groups (CH₂=CH-), possessing strong reactivity. Under platinum catalysis, they undergo efficient hydrosilylation with hydride silicone oil, forming stable 3D crosslinked networks; in the presence of peroxides and other vulcanizing agents, they can crosslink with rubber molecular chains. Dual-end dual-active sites mean a single 218 molecule can connect two polymer chains simultaneously, doubling crosslinking efficiency.
• 10-20mPa·s Ultra-Low Viscosity Skeleton: Low polymerization degree and narrow molecular weight distribution grant it an ultra-low viscosity of 10-20mPa·s (20℃) — this viscosity ranks as "flowing liquid" among vinyl silicone oils, far below conventional vinyl-terminated silicone oils (50-100,000cSt). Ultra-low viscosity brings three major process advantages: ① more uniform dispersion and lower mixing energy when pre-blending with fillers like fumed silica; ② as raw rubber prepolymer replacing vinyl double-head caps, the molecular chain segment already contains siloxane structure, enabling more flexible molecular design; ③ reducing initial system viscosity in LSR and silicone gel formulations, improving potting fluidity and mold filling.

Performance Leap: From "Double-Head Cap Coarse Tuning" to "Oligomeric Prepolymer Precision Control"

• Replacing Vinyl Double-Head Caps: As raw rubber prepolymer, 218 can replace traditional vinyl double-head caps — its molecular structure already contains a siloxane chain segment, providing more flexible molecular structure control and more optimized process parameters in polymerization reactions, effectively improving the processing performance and mechanical strength of silicone rubber.
• HTV Base Material Main Raw Material: As the base material main raw material in HTV silicone rubber, the dual-end vinyl groups crosslink with rubber molecular chains under peroxide vulcanization, granting HTV silicone rubber excellent mechanical strength, elastic recovery, and high-low temperature stability — an ideal choice for manufacturing sealing rings, gaskets, cable insulation layers under harsh working conditions.
• Addition-Cure LSR & Silicone Gel Main Raw Material: Undergoes efficient hydrosilylation with hydride silicone oil under platinum catalysis, achieving rapid curing at room or medium temperature; the reaction has no by-products, low shrinkage, and is easy to control, making the resulting liquid silicone rubber suitable for precision potting, flexible molds, medical catheters, baby nipples, and other fields with extremely high purity and dimensional accuracy requirements.
• Polymer Material Modifier: Reacts with polyurethane, acrylic, and other materials to introduce polysiloxane segments via block or graft copolymerization, significantly improving weather resistance, aging resistance, UV resistance, and toughness; meanwhile, the flexible siloxane backbone can effectively toughen the matrix and improve low-temperature flexibility.
• High Purity Low Volatility Safety: Volatile matter (105℃/2h) ≤0.1%, high purity grade provides reliable quality assurance for downstream high-end applications; flash point ≥61℃ provides basic safety guarantee; non-hazardous chemical storage and transport ensures high production safety.

Application Penetration: From HTV Seals to Medical LSR

• HTV Silicone Rubber Raw Rubber Synthesis (Main Battlefield): As base material main raw material and vinyl double-head cap replacement for synthesizing HTV silicone rubber raw rubber — widely used in sealing rings, gaskets, cable insulation layers, and other harsh-condition components.
• Addition-Cure Liquid Silicone Rubber (LSR): As main raw material for injection thermoforming silicone rubber — smart watch bands, TWS earbud tips, mobile phone keys, baby nipples, medical catheters, laryngeal mask airways, etc.; ultra-low viscosity ensures fluidity demands for miniaturized, high-precision molding (wall thickness as low as 0.2mm).
• Silicone Gel: Preparing electronic component protection gels, optical device bonding gels, medical sensor interface gels — featuring excellent light transmittance, cushioning, and damping.
• PU & Acrylic Modification: Improving weather resistance, aging resistance, UV resistance, and toughness of PU and acrylic via block/graft copolymerization; reducing surface energy in coatings, imparting excellent release and stain resistance.
• In-Situ Crosslinking Specialty Applications: Leveraging the ethoxy-terminus hydrolytic crosslinking with ethanol generation for use as in-situ crosslinking agent in specific scenarios.

IOTA Technical Guide: Avoid Water & Fire, 1-Year Fresh Efficacy

• Application: As HTV base material main raw material directly participates in compounding; as raw rubber prepolymer replaces vinyl double-head caps in polymerization; as LSR and silicone gel main raw material compounds with hydride silicone oil and platinum catalyst; as PU/acrylic modifier introduces siloxane segments via copolymerization; addition amount determined per target vinyl content and crosslinking density gradient testing.
• ⚠️ Taboo: During storage, no contact with open flame and water; ethoxy termini easily hydrolyze and crosslink generating ethanol, avoid contact with moisture and water to prevent premature crosslinking; avoid coexistence with strong acids, strong bases, tin compounds, and other platinum catalyst poisons.
• Storage: Non-hazardous chemical storage and transport; stable at room temperature; keep ventilated and dry, prevent sunlight and rain; original packaging shelf life 1 year, after expiration must re-inspect all indicators qualified before use.
• Handling: Colorless transparent liquid, extremely low viscosity (10-20mPa·s), prevent splashing and moisture intrusion during feeding; recommend operation in dry environment, use up quickly after opening to maintain activity.

Industry Insight: The "viscosity - vinyl content - polymerization degree" triangle of vinyl silicone oil directly determines the processing performance of silicone rubber and the mechanical properties of vulcanizates — low-viscosity, high-vinyl-density, controllable-polymerization-degree active intermediates are the key to realizing molecular design freedom in silicone rubber. IOTA 218, with "ethoxy-terminated small-molecule linear polydimethylsiloxane + dual-end vinyl + 10-20mPa·s ultra-low viscosity + volatile matter ≤0.1% + CAS 26710-23-6 + non-hazardous storage and transport" hard indicators, fills the key supply chain link for domestic low-viscosity vinyl silicone oil in HTV raw rubber, addition-cure LSR, silicone gel, and PU/acrylic modification fields, providing import-substitution for downstream high-end silicone rubber and polymer modification enterprises. This confirms domestic functional silicone oils are leaping toward "oligomeric active prepolymers", with growing technical say in vinyl silicone oil intermediates.