HS (Hydrogenated Styrenic) VII (CAS 66070-97-5) – Premium Shear-Stable Viscosity Modifier | China Manufacturer & Bulk Supplier

🚗 1. Ultra-Low Viscosity Engine Oils - Next-Generation Fuel Economy Lubricants

The global trend toward ultra-low viscosity engine oils (0W-16, 0W-20, 5W-20) to meet increasingly stringent fuel economy regulations (CAFE, Euro 7, China 6b) demands a VII with the most demanding combination of properties: extremely low cold cranking viscosity, robust high-temperature film thickness, and long-term shear stability over extended drain intervals. HS (Hydrogenated Styrenic) VII uniquely satisfies all three requirements simultaneously. Its SSI ≤ 15% means a lubricant formulated to 0W-20 on day one will still meet 0W-20 viscosity limits after 15,000–20,000 km of service - a performance guarantee that OCP and PMA struggle to match in these ultra-thin oil grades.

Dispersant-type HS VII grades are also available, incorporating polar functional groups that help suspend soot and combustion by-products - supporting API SP, ACEA C5/C6, and ILSAC GF-6 compliant extended drain interval formulations.

🌬️ 2. Wind Turbine Gear Oils & Long-Drain Industrial Lubricants

Wind turbine gearboxes operate under continuous high shear loads with oil change intervals of 3–5 years or 60,000+ operating hours. Over such extended service periods, VII shear stability is the single most critical factor determining whether the lubricant maintains adequate viscosity at drain. HS VII's block polymer architecture, combined with full hydrogenation, delivers the lowest permanent viscosity loss of any commercial VII - making it the industry standard for wind turbine gear oils (ISO VG 320/460, DIN 51517-3 CLP) approved by major OEMs including Vestas, Siemens Gamesa, and GE Renewable Energy. It is equally well-suited to high-pressure hydraulic systems and compressor oils requiring long service life.

🔄 3. Premium ATF, CVTF & Specialty Transmission Fluids

Modern automatic transmissions (8-speed+), CVT, and dual-clutch transmissions apply extreme shear stress on transmission fluid in torque converters, gear sets, and clutch packs. HS VII's superior shear stability ensures that ATF viscosity stays within OEM specification throughout the fluid's service life - a critical requirement for approved fluids targeting GM DEXRON VI, Toyota WS, ZF LifeGuard 9, and equivalent OEM standards. Its outstanding low-temperature fluidity (pour point ≤ -25°C) also contributes to faster transmission warm-up and smoother low-temperature shifting, improving the overall driving experience in cold climates.

HS VII commands a price premium over OCP due to the complexity of the hydrogenation process and specialized raw materials (styrene-diene block copolymer precursors). When evaluating total formulation cost, always benchmark on a per-liter-of-finished-lubricant basis: HS VII's higher activity per unit mass often means lower treat rates, partially offsetting its unit price premium. Long-term supply agreements with volume commitments unlock the most competitive pricing and ensure allocation priority during periods of raw material tightness.

Q1: What is the CAS number for Hydrogenated Styrenic VII?

The CAS number is 66070-97-5 for hydrogenated styrene-diene block copolymer (HS VII). It is also referred to as SEBS-based VII, Hydrogenated SBS, or Star Polymer VII in some trade literature. Please specify your target application (engine oil, ATF, industrial gear oil) and base oil group (II/III/IV) when requesting a grade recommendation.

Q2: Why is HS VII preferred for wind turbine gear oil?

Wind turbine gearboxes demand oil drain intervals of 3–5 years. Over this period, a VII with even moderate shear degradation can cause the oil to fall out of viscosity grade specification, risking gear micropitting and bearing damage. HS VII's SSI ≤ 15% - the lowest of any commercial VII type - ensures the oil maintains its viscosity classification throughout the full drain interval. Most major wind turbine OEM gear oil approvals (Vestas, Siemens Gamesa, Nordex, GE) either require or strongly prefer HS VII-based formulations for this reason.

Q3: What is the significance of ≥ 98% hydrogenation degree?

Residual carbon-carbon double bonds (unsaturation) in un- or partially hydrogenated styrenic polymers are vulnerable to thermal oxidation at engine temperatures, leading to polymer chain degradation, deposit formation, and viscosity loss. A hydrogenation degree of ≥ 98% eliminates nearly all these reactive sites, giving HS VII thermal-oxidative stability comparable to fully saturated polymers like OCP - while retaining the superior shear stability and low-temperature performance of the styrenic block architecture.

Q4: Can HS VII be used in Group IV (PAO) synthetic base oils?

Yes - HS VII exhibits excellent compatibility with PAO Group IV base oils and is widely used in synthetic and semi-synthetic engine oil formulations. Its solubility in PAO is superior to OCP (which can be limited in high-PAO content blends) due to the polar segments of the styrenic block copolymer structure. This makes HS VII the preferred VII for fully synthetic 0W-20 and 0W-16 PAO-based engine oils.

Q5: What documentation is provided with each shipment?

Every Sinolook shipment comes with a complete documentation package: Certificate of Analysis (CoA), Safety Data Sheet (SDS/MSDS), commercial invoice, packing list, Bill of Lading, and Certificate of Origin. Third-party inspection reports (SGS, Intertek, BV) and REACH/RoHS compliance documentation are available on request.