Viscosity Modifiers & Base Stocks
Viscosity modifiers are polymeric additives used to control how lubricant viscosity changes with temperature. They can increase viscosity, improve viscosity index, and help lubricants maintain the required viscosity across a wider operating temperature range. Selecting the right viscosity modifier requires balancing three critical attributes: viscosity index improvement, thickening efficiency, and shear stability.
Liquid viscosity modifiers provide convenient handling and incorporation when manufacturing industrial fluids and lubricants, while solid polymer options can provide additional flexibility in formulation and economics.
Functional Products Inc. offers all the major viscosity modifier chemistries because there is no single polymer that is best for every application. Using one viscosity modifier for everything may simplify logistics, but it often requires compromises in performance, treat rate, or cost.
Our approach is to provide the right tool for the job. From OCP and styrenic polymers to PMAs, EPOs, and specialized low-temperature polyolefins, Functional Products can help identify the viscosity modifier technology that best fits the requirements of your next formulation.
Available in drums, totes (275gal or 330gal IBC), bulk tanker truck up to 6000 gallons, isotainer, and FlexiTank.
Additional Information
- Olefin Copolymers
- Ethylene-Propylene Oligomers
- Polybutene / Polyisobutylenes
- Styrene Viscosity Modifiers
- Polymethacrylates
- Low-Temperature Polyolefins
- Need a specialty biobased or NSF HX-1 incidental food contact option?
Frequently Asked Questions about Viscosity Modifiers
1. What is a viscosity modifier in lubricants?
A viscosity modifier (VM) is a polymer additive that improves an oil’s viscosity index, keeping it thicker at high temperatures and more fluid at low temperatures for consistent performance.
2. Why are viscosity modifiers used in lubricants and hydraulic fluids?
They stabilize lubricant film thickness across operating temperatures, improving efficiency, wear protection, and cold-start performance. Low viscosity oil can be increased to any higher viscosity, ISO Viscosity Grade, or SAE Viscosity Grade giving formulators more flexibility on their raw materials and costs. Viscosity index, the temperature-viscosity trade-off of a lubricant, can also be tuned through viscosity modifier use.
3. What types of viscosity modifiers does Functional Products offer?
Functional Products manufactures OCP (V-150/V-160), PMA (M Series), Styrene Copolymers (V-4300 Series), EPO (V-730 Series), and specialties like our EAL-grade (V-500 Series) viscosity modifiers for petroleum and biodegradable systems. These are a core part of the FUNCTIONAL brand polymer additives.
4. What is the difference between OCP and PMA viscosity modifiers?
OCP (olefin copolymer) VMs provide strong shear stability and cost-effectiveness; PMA (polymethacrylate) VMs offer higher thickening efficiency, dispersancy, and oxidation resistance. Styrene copolymers bridge the gap between performance and cost effectiveness.
5. What are the advantages of Functional’s OCP V-150 and V-160 Series?
They deliver balanced shear stability, high VI improvement, and broad base-oil compatibility, making them ideal for hydraulic, gear, and engine oils. We offer shear stability indexes (P-SSI) from 20 to 60 across the V-150 / V-160 line-up.
6. How does the FUNCTIONAL M Series (PMA) improve lubricant performance?
The M Series enhances cleanliness, soot dispersancy, and oxidation control, improving deposit control and long-term stability in diesel and crankcase oils.
7. What makes the Styrene Copolymer V-4300 Series unique?
Styrene copolymer VMs add film strength and mild EP performance, offering both viscosity control and mechanical protection under heavy loads.
8. What is an EPO (Ethylene-Propylene-Octene) viscosity modifier?
EPO terpolymers combine high shear stability and oxidative durability, bridging the gap between OCP cost and PMA performance.
9. What is the FUNCTIONAL V-500 Series for EAL lubricants?
The V-500 Series are biodegradable viscosity modifiers listed under EU Ecolabel and OECD 301, designed for marine, forestry, and agricultural EAL formulations.
10. Are Functional viscosity modifiers compatible with synthetic base oils?
Yes — all FUNCTIONAL VMs dissolve cleanly in PAO, PAG, Group III, and ester base oils, ensuring formulation flexibility. Let our technical team find the best fit for compatibility, performance, and cost for your next project!
11. How do viscosity modifiers improve fuel efficiency and equipment life?
By maintaining proper film thickness, they reduce metal-to-metal contact, lower friction, and extend lubricant life under both hot and cold conditions.
12. How are viscosity modifiers measured for performance?
Key parameters include kinematic viscosity at 40C (KV40), kinematic viscosity at 100C (KV100), viscosity index (ASTM D2270), shear stability index (ASTM D6022/D6278), and HTHS viscosity. Handling viscosity during use is another key factor that can determine which option is right for your plant.
13. What is the typical treat rate for viscosity modifiers?
Most FUNCTIONAL polymers are used at 2–12 %, depending on base-oil viscosity, target VI, and thickening efficiency.
14. What are the main benefits of PMA viscosity modifiers in hydraulic oils?
They provide excellent shear stability, oxidation control, and water tolerance, extending oil life and reducing varnish formation.
15. How do OCP viscosity modifiers perform in shear stability testing?
The V-150 and V-160 Series exhibit low SSI values as low as 20 under ASTM D6278, maintaining viscosity even after high-shear operation.
16. What are the advantages of EPO (V-730 Series) over traditional OCP polymers?
EPO polymers offer higher shear stability, lower permanent viscosity loss, and better oxidation resistance, ideal for long-life gear and transmission oils.
17. Do styrene copolymer viscosity modifiers provide any anti-wear benefits?
Yes. FUNCTIONAL V-4300 polymers create load-bearing polymer films that provide mild EP and anti-wear protection in gear and chain oils.
18. Are Functional Products’ viscosity modifiers suitable for biodegradable and marine oils?
Yes — the V-500 Series are biodegradable, non-toxic, and compliant with VGP (Vessel General Permit) and EU Ecolabel standards.
19. Can viscosity modifiers be used in grease formulations?
Yes — small additions of OCP or PMA polymers improve grease elasticity, bleed control, and water resistance without affecting consistency. The use of viscosity modifiers to replace bright stock and polybutene allows formulators to use lower viscosity base oils which improves the low temperature torque and fluidity of grease. We recommend you look at our Grease Additives portfolio for specially tuned options.
20. How do viscosity modifiers interact with pour-point depressants (PPDs)?
They work synergistically, stabilizing wax crystal networks and improving cold-flow performance.
21. What affects the shear stability of a viscosity modifier?
Molecular weight, polymer architecture (linear vs. star), and base-oil compatibility all determine shear stability under mechanical stress.
22. Do viscosity modifiers affect demulsibility or air release?
Proper treat rates maintain ASTM D1401 demulsibility and ASTM D3427 air release, ensuring hydraulic and gear system performance. In specialty base fluids, a FUNCTIONAL DM Series demulsifier or DF Series defoamer can help.
23. How can viscosity modifiers help reduce oil consumption?
They improve film strength at high temperatures, reducing evaporation loss and consumption in engines and gearboxes.
24. Are Functional viscosity modifiers oxidatively stable?
Yes — they are formulated for high thermal and oxidative stability to resist breakdown during long-term service.
25. How can I select the right viscosity modifier for my application?
Contact Functional Products Inc. for technical support. Our R&D team can recommend the best OCP, PMA, Styrene, EPO, or biodegradable VM for your base oil, viscosity target, and regulatory needs.