Technical Specifications
This grade family is available as 4 CheMost grades — the differences are in the columns below.
| Property | Unit | VII6000 | VII6000S | VII8000 | VII9000 | Test Method |
|---|---|---|---|---|---|---|
| Shear Stability Index (SSI) | 45 | 45 | 26 | 20 | ASTM D6278 | |
| Viscosity at 100°C | mm²/s | 1000 | 1500 | 1100 | 2100 | ASTM D445 |
| Density at 20°C | kg/m³ | 860 | 865 | 880 | 880 | ASTM D4052 |
| Water content | PPM | 20 | 20 | 20 | — | ASTM D95 |
| Flash point | °C | 190 | 200 | 170 | >200 | ASTM D93 / D92 |
| Solubility (Mineral Group I–III) | >20% | >20% | >20% | — | — | |
| Appearance | Colorless or light yellow viscous liquid | Colorless or light yellow viscous liquid | Colorless or light yellow viscous liquid | Colorless or light yellow viscous liquid | Visual |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Molecular Structure
Molecular structure · olefin copolymer (OCP)
–[CH₂–CH₂]ₓ–[CH₂–CH(CH₃)]ᵧ–
Idealised repeat unit of the amorphous ethylene–propylene copolymer (OCP); the x : y ratio is set by the ethylene / propylene content.
What Is a Liquid Olefin Copolymer (OCP) Viscosity Modifier?
CheMost supplies a ready-to-blend liquid olefin copolymer (OCP) viscosity modifier — the oil-soluble ethylene-propylene copolymer that holds the dominant share of the engine-oil viscosity-modifier market thanks to its high thickening efficiency and low cost. Dissolved in a high-quality diluent oil, it is a polymer-in-oil concentrate that thickens the finished lubricant at high temperature and raises its viscosity index, so the oil stays close to its target viscosity across the operating range rather than thinning sharply as it heats up.
An OCP works because the dissolved polymer coil expands as temperature rises, offsetting the natural thinning of the base oil and keeping the oil film intact when the engine is hot. This is the mechanism behind every multigrade oil: a low-viscosity base stock for cold-start flow, plus an OCP to build the high-temperature viscosity. CheMost’s grades are non-functionalised rheology modifiers — pure viscosity control — so dispersancy, detergency and antiwear come from the matching additives in the package rather than from the polymer itself.
This page covers the four liquid concentrate grades — VII6000, VII6000S, VII8000 and VII9000 — which differ in shear stability and thickening power, set out grade-by-grade in the Technical Specifications table above. Because they arrive already dissolved in oil, they can be metered straight into a blend; the same OCP chemistry is also offered as a solid EPM bale for blenders who prefer to dissolve the raw polymer in-house.
How an OCP Viscosity Modifier Works
Temperature-responsive thickening
The ethylene-propylene chains are coiled tightly in cold oil and contribute little to viscosity; as the oil heats, the coils expand and interact more with the solvent, raising viscosity exactly where the base oil would otherwise thin. The net effect is a flatter viscosity-temperature curve — a higher viscosity index — which is what lets a single oil meet both a winter (cold-crank) and a summer (high-temperature) grade.
Thickening efficiency vs molecular weight
Thickening efficiency rises with polymer molecular weight and ethylene content, so a higher-molecular-weight grade reaches the same target viscosity at a lower treat. That efficiency is the OCP’s main economic advantage — but it trades off against shear stability, which is the axis the four grades are tuned along.
Shear stability and “stay-in-grade”
In high-shear zones — bearings, the ring-liner contact, gear meshes — long polymer chains can be temporarily aligned (temporary viscosity loss, recovered at rest) and permanently broken (permanent viscosity loss, irreversible). The shear stability index (SSI, ASTM D6278 Kurt Orbahn) measures the permanent fraction lost; a lower SSI grade keeps its viscosity better and helps the oil “stay in grade” over its drain interval.
High- and low-temperature rheology
At operating temperature the polymer contributes to high-temperature high-shear (HTHS) viscosity, which protects the oil film in loaded bearings; at low temperature the amorphous OCP adds little to cold-crank and pumpability viscosity, leaving those to the base oil and the pour-point depressant. Balancing HTHS, KV100, CCS and MRV is the core of multigrade formulation.
Choosing Between VII6000, VII6000S, VII8000 and VII9000
All four grades are the same olefin-copolymer chemistry as a liquid concentrate; the choice is set by the shear-stability/thickening trade-off and by handling viscosity. The numbers are in the Technical Specifications table at the top of this page — here is how to read them:
VII6000 (SSI 45) — general multigrade thickener. The highest-thickening-efficiency grade: it reaches a target viscosity at the lowest polymer level, which makes it the cost-effective default for monograde and general multigrade engine oils, industrial oils, greases and metalworking fluids where severe mechanical shear is not the governing constraint.
VII6000S (SSI 45) — higher-solids version of VII6000. The same shear-stability tier as VII6000 but a higher solid (polymer) content, reflected in its higher concentrate viscosity (1500 vs 1000 mm²/s) and flash point. Choose it to deliver more polymer per kilogram of concentrate — fewer kilograms shipped and metered for the same thickening — where your blending equipment can handle the higher handling viscosity.
VII8000 (SSI 26) — shear-stable, high-grade engine oils. A more shear-stable grade that holds viscosity better under sustained high-shear service and has only a weak effect on low-temperature pumpability, which suits high-grade gasoline and diesel engine oils. It needs a little more polymer than VII6000 to hit the same viscosity, the price of the better stay-in-grade behaviour.
VII9000 (SSI 20) — maximum shear stability / thickener grade. The most shear-stable liquid grade and the highest-viscosity concentrate (2100 mm²/s), positioned as a thickener and viscosity modifier for the most demanding high-grade lubricants — severe-duty heavy-duty diesel, gear and long-drain oils — where permanent viscosity loss must be kept to a minimum.
As a rule of thumb, move down the SSI ladder (45 → 20) as mechanical shear severity and drain interval increase, and accept the modestly higher treat that the more shear-stable grades require. If you are unsure which grade fits your viscosity target and base-oil set, our technical team can advise on request.
Applications
This OCP viscosity modifier is used as the rheology-control component in formulations targeting the categories below; it builds high-temperature viscosity and viscosity index but carries no detergency, dispersancy or antiwear of its own.
Multigrade engine oils (PCMO & HDDEO)
The primary use: converting a low-viscosity base stock into a multigrade passenger-car or heavy-duty diesel oil (for example SAE 10W-30, 15W-40). Lower-SSI grades (VII8000, VII9000) are preferred for heavy-duty and long-drain oils where shear durability matters most.
Industrial & gear oils
Builds viscosity index and film thickness in industrial gear oils, circulating oils and tractor/transmission fluids, extending oil life and improving the viscosity-temperature behaviour of multigrade industrial lubricants.
Hydraulic & high-VI fluids
Used to formulate high-viscosity-index and multigrade hydraulic oils, where the shear-stable grades help the fluid hold its viscosity through high-pressure pumps and valves over the service interval.
Greases & metalworking fluids
Small additions improve the body, film strength and water resistance of greases, and VII6000/VII6000S are dosed at low levels in metalworking oils and fluids for controlled viscosity build.
Finished-oil OEM and industry approvals (API, ACEA, ILSAC and OEM bench sequences) are held by the fully formulated oil, not by an individual viscosity modifier.
Treat Rate & Formulation Notes
The technical data sheet gives the recommended concentrate treat rates below. These are for the liquid concentrate (polymer dissolved in oil), so they are higher than the neat-polymer figure: in published engine-oil studies, roughly 0.5–1.5 wt% of neat OCP polymer is enough to lift a base oil to a multigrade KV target, with the more shear-stable (lower-SSI) grades needing more polymer for the same thickening. Because a liquid concentrate is only part polymer, the concentrate doses higher than that.
| Application | Concentrate treat rate (TDS) |
|---|---|
| Engine oil — VII6000 / VII6000S | 1.0–10.0 wt% |
| Engine oil — VII8000 / VII9000 | 2.0–10.0 wt% |
| Industrial oils | 0.5–2.0 wt% |
| Metalworking oils / fluids (VII6000 / VII6000S) | 0.3–1.0 wt% |
Set the exact level from your viscosity target, not from the range alone: thickening efficiency scales with the grade’s SSI, so a higher-SSI grade (VII6000) reaches the target at the low end of the range while a lower-SSI grade (VII9000) sits higher. Low-temperature behaviour is governed jointly by the base oil, the viscosity modifier and the pour-point depressant — the three must be co-optimised, because the PPD, not the VM, is the primary control over pumpability (MRV) at cold temperatures.
The TDS treat ranges above are the manufacturer’s recommendations; the right level for your oil depends on the viscosity grade target, base-oil set and the rest of the package. CheMost can provide formulation and treat-rate support on request.
Formulating With an OCP Viscosity Modifier — Complementary Additives
An OCP controls viscosity only; a finished multigrade oil pairs it with the additives that cover the rest of the performance envelope:
Pour-point depressants
The PPD is the primary guardian of low-temperature pumpability; it must be matched to the base oil and the viscosity modifier together, because the wrong VM/PPD pairing can drive up MRV viscosity or cause yield-stress failures. Amorphous OCPs like these grades are generally well-behaved with conventional PPDs.
Ashless dispersants
Dispersants suspend soot and sludge — the function an OCP does not provide. (Where dispersancy is grafted onto the polymer itself, the result is a dispersant OCP; CheMost’s grades here are the non-functionalised type, so dispersancy comes from a separate dispersant.)
Antioxidants
Aminic and phenolic antioxidants protect both the base oil and the polymer from oxidative degradation, preserving the viscosity the OCP builds over a long drain interval.
Detergents & TBN boosters
In an engine-oil package the OCP works alongside overbased detergents and the ZDDP antiwear system; the viscosity modifier sets the grade while the DI package delivers cleanliness, acid control and wear protection.
Documentation, Qualification & Regulatory Support
Standard documentation — Certificate of Analysis (COA, per shipment), Technical Data Sheet (TDS) and Safety Data Sheet (SDS, GHS/CLP) — is provided. The full TDS is available on request rather than as a public download. Additional support is available on request:
Regulatory documentation
REACH, TSCA and country-specific market-registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom shear-stability grades and packaging — metal drum, IBC, ISO tank.
Formulation support
Grade selection, treat-rate calculation and viscosity-target guidance from our technical team.
Packaging & Supply
This liquid OCP viscosity modifier is stocked and shipped worldwide, with a typical lead time of 1–15 days and a 36-month shelf life at ambient temperature (maximum storage 50°C; maximum blending temperature 70°C). Samples and quotations are answered within 12 hours.
Packaging
170 kg drum · 900 kg IBC tank (VII8000 in drum).
Minimum order
1 drum or 1 IBC — no minimum order value.
Incoterms
FOB · CIF · EXW, to suit your freight arrangement.
Loading ports
All major Chinese ports.
Frequently Asked Questions
What is an OCP viscosity modifier?
An OCP (olefin copolymer) viscosity modifier is an oil-soluble ethylene-propylene copolymer that thickens a lubricant at high temperature and raises its viscosity index, so the oil stays close to its target viscosity from cold start to full operating temperature. It is the most widely used viscosity index improver in engine oils because of its high thickening efficiency and low cost. CheMost supplies it as a ready-to-blend liquid concentrate in four shear-stability grades.
What is the difference between VII6000, VII6000S, VII8000 and VII9000?
They are the same OCP chemistry at different shear-stability tiers. VII6000 (SSI 45) is the highest-thickening, most cost-effective grade for general multigrade and monograde oils; VII6000S is the same tier at a higher solid content (more polymer per kilogram). VII8000 (SSI 26) is more shear-stable for high-grade engine oils, and VII9000 (SSI 20) is the most shear-stable, highest-viscosity thickener grade for severe-duty and long-drain lubricants. The full grade-by-grade specifications are in the table above.
What does the shear stability index (SSI) tell me?
SSI is the percentage of the viscosity contributed by the polymer that is permanently lost when the oil is sheared (ASTM D6278). A lower SSI means the polymer resists chain scission better, so the oil holds its viscosity and “stays in grade” longer — important for heavy-duty and long-drain service. The trade-off is thickening efficiency: a lower-SSI grade needs slightly more polymer to reach the same viscosity, so SSI is the main axis you choose a grade along.
How much viscosity modifier should I use?
The TDS recommends 1.0–10.0 wt% of the liquid concentrate in engine oils (2.0–10.0 wt% for VII8000/VII9000), 0.5–2.0 wt% in industrial oils and 0.3–1.0 wt% in metalworking fluids. As a guide, roughly 0.5–1.5 wt% of neat OCP polymer lifts a base oil to a multigrade target, and the liquid concentrate doses higher because it is polymer dissolved in oil. Set the exact figure from your viscosity target and confirm with our team for your base-oil set.
Should I choose the liquid concentrate or the solid bale?
The liquid concentrate on this page is dissolved in oil and ready to meter straight into a blend — the simplest option for most blenders. The same OCP chemistry is also sold as a solid EPM bale, which is more economical per unit of polymer but must be ground and dissolved in hot oil (100–130°C) before use — suited to blenders with in-house dissolving capacity. Choose by whether you have that capacity; both deliver the same finished-oil performance.