Which lubricant to chose PG or PAO?

Which lubricant to choose PG or PAO?

Molyduval lubricants with PG (polyglycol) and PAO (poly-alpha-olefin) bases differ significantly in their chemical composition, lubrication properties, temperature performance, and sealing compatibility. Here’s a comparison:

PG (Polyglycol) Base lubricants (Molyduval Syntholube G 220 for example)

• Chemical Composition: Made from synthetic polyglycol oils, which offer excellent thermal stability and low friction characteristics.
• Lubrication Properties: 

1. High lubricity, particularly in applications involving sliding contacts.
2. Low tendency for hydrocarbon varnish formation, making them ideal for clean operations.

• Temperature Performance: 

1. Good thermal stability up to +150°C to +200°C.
2. Low pour point ensures good low-temperature performance (-30°C to -50°C).

• Sealing Properties: 

1. PG lubricants are polar, which makes them less compatible with some sealing materials (like elastomers) and certain paints.
2. Tend to absorb water more readily than PAO greases, which may 

• Applications: Often used in gearboxes, worm gears, and other applications requiring excellent sliding performance and minimal energy loss.

Molyduval Syntholube A 220 - PAO (Poly-Alpha-Olefin) Base oils

• Chemical Composition: Made from synthetic hydrocarbons, PAOs closely mimic mineral oils but offer improved performance.
• Lubrication Properties: 

1. Excellent film strength and stability under high loads.
2. Generally lower friction coefficients than PG greases in rolling contact applications.

• Temperature Performance: 

1. Broad temperature range, typically -50°C to +150°C. Some formulations can exceed this range with proper thickeners.
2. Lower evaporation rates at high temperatures compared to PG greases.

• Sealing Properties: 

1. Chemically inert and compatible with most sealing materials (e.g., nitrile, Viton, EPDM).
2. Hydrophobic properties improve water resistance and sealing performance in wet environments.

• Applications: Widely used in bearings, automotive applications, and other environments requiring broad compatibility and balanced performance.

Comparison and Suitability

Which is Better?

• For Lubrication Properties: Depends on the application: 

1. Sliding applications (e.g., gears): PG greases and oils have less friction- better lubrication.
2. Rolling applications (e.g., bearings): PAO greases and oils.

• For Temperature Performance: Both perform well in their respective ranges, but PAOs have better seal compatibility and better low temperature properties. 
• For Sealing Properties: PAO greases are better due to their inertness and water resistance.