PMA viscosity index improvers in gear oil

The modern gear oil transmission device is for high loading, high speed, and miniaturization, which puts higher demands on gear oil's performance. The gear oil needs to have good low-temperature liquidity and high-temperature oil strength to keep a suitable viscosity in a wider temperature range.

Therefore, gear oil needs viscosity index improvers for wider temperatures uses.

 

 

What are viscosity index improvers and the mechanism?

What are Viscosity Index Improvers (VIIs)?

Viscosity indices are used to measure changes in viscosity. Viscosity index improvers are used to improve the oil's viscosity at suitable temperatures.

Viscosity index improvers mainly include polymethacrylate (PMA), hydro styrene-vinyl diene (HSD), ethylene propylene copolymer (OCP), and polyisobutylene (PIB).

The mechanism of viscosity index modifiers.

Viscosity index improvers exploit the thermal expansion and contraction of high-molecular chains, giving multigrade oil low-temperature start-up and high-temperature viscosity, resulting in more stable lubrication at a given temperature.

 

What are the special requirements of gear oil for VIIs?

Compared with engine oil, when choosing viscosity index improvers for gear oil, you should consider the following 4 parts: adhesion-enhancing ability, low-temperature performance, shear stability, and oxidation stability.

1. Adhesion-enhancing: the higher adhesion-enhancing ability can achieve low dosage, high viscosity grade, and stable gear oil formulation.

2. Low temperature performance: the gear oil can reach the gear meshing area, and low temperature performance can ensure the gears can get quick lubrication under cold temperatures.

3. Shear stability: the gear will produce high shear stress when meshing. The lower the shear stability index (SSI), the better, which can protect the high molecular chains completely under a strict shear environment and avoid viscosity loss and the oil thinner.

4. Oxidation stability: it depends on the cleanness and service life of gear oil under high-temperature operating conditions. Good oxidation stability can prevent the oil decay.

 

The choice of viscosity index in gear oil.

The use of viscosity index improvers will influence the oil shear stability, which is important for oil performance stability. Misusing VIIs will decrease the viscosity of the high molecular compound in the gear oil under shear stress, which will cause friction and failure.

The degree of shear stress in various oil products is as follows:

gear oil＞hydraulic oil＞automatic transmission oil＞diesel engine oil＞gasoline engine oil

 

The choice of viscosity index improvers:

The VIIs mainly include HSD, OCP, PMA, and PIB. Normally, OCP and HSD are not recommended for gear oil; instead, PMA and PIB are suitable for vehicle gear oil.

PIB has good high-temperature shear stability and oxidation stability that can not be dissolved at high temperatures. However, the low temperature effects are not good that the viscosity increases fast under low temperatures.

The PMA viscosity index modifier in gear oil.

PMA has an excellent low-temperature performance that can improve the oil's viscosity. It has good oxidation stability, but the thickening ability, thermal stability, and shear stability are relatively low. It's suitable for gear oil that has a higher requirement for low-temperature performance.

Chorus PMA viscosity index improver VII T6104 is a high-quality polymethacrylate (PMA) viscosity index improver. Owing to its excellent shear stability, used for gear oil can improve the oil's viscosity index and low-temperature performance.

 

Take 150N base oil as an example, not adding T6104, the viscosity is 5.0cSt, after adding 10%, the thickening ability reach to 8.0, the growth rate is 60%. And after 20% T6104, the viscosity reaches 12.0, and the growth rate is 140%.

 

It can be seen that the T6104 dosage is much lower, which can not improve the viscosity performance but also reduces formulation cost and leaves more room for other additives.

 

PMA viscosity index modifier T645 is a high-grade PMA viscosity index, suitable for hydraulic, gear oil, etc, with the features of excellent shear stability that can improve the oil viscosity and performance under extreme weather.

There is no universal PMA viscosity index improver in gear oil.

If you are pursuing quick lubrication and economy, choose PMA first.

We can provide you with different PMA viscosity indices according to different performance requirements.

Chorus is a professional lubricant supplier in China. Whether you need PMA VIIs with excellent low temperatures or other kinds of viscosity index improvers, HSD, and OCP, we can provide you with our professional solution and recommend the most suitable VIIs.

 

Contact us and get the most professional solution and the latest price.