Gear oils are normally split into 2 different oils:
- Automotive (manufacturing)
- Industrial (processing)
Certain parameters should be considered when selecting gear oil:
- Gear design
- Gear material
- Conditions of operation
The most important parameters of the gear oil:
- Viscosity index
- Low pour point
- Good shear stability
To obtain a control leakage of the oil
To limit the noise generation of the gear
The viscosity index (VI) is the rate of change of viscosity between two temperatures. The lower the VI, the greater the drop in viscosity as the oil warms up. The higher the VI, the less the drop in viscosity as the oil warms up. The flow properties change at different temperatures and conditions, for example: during a cold start, the greatest strain occurs due to the heavy drag from the syrup-like oil. At first the oil’s viscosity will thin out rapidly, however as soon as the engine warms up the viscosity will stabilise as a running temperature is reached.
Polybutenes have excellent qualities for the automotive gear oil industry:
- Good shear stability
- Viscosity index improver in the formulation of high quality multigrade oils
- Efficient oil thickness at high temperature.
- Improve pour point of the formulation
POLYBUTTM 150, 200, 600 fit very well but also the lower viscous PIBs can be used, depending on the requirements for the gear.
PAO mixed with the PIB will increase the price of the formulation but will also improve the Viscosity index.
They represent 60% to 75% of the gear oils.
There are gear oils for open and closed systems:
Open system gear oils: are used in industrial open gears at high temperatures in open gearing for mining, ore processing.
Closed system gear oils: are used in extreme conditions to splash, spray and/or mist within the oil system, for example roller bearings, elastic clutches.
To maximise the energy efficiency of the gear oils, the polybutene needs to have:
- high shear
- high VI
- good low temperature properties
- good adhesion so low
There are different process needs for metalworking fluids:
- Cutting, drawing, grinding, pressing, rolling and stamping
A lubricant is used to maintain a protective film between the die or tool and the metal billet (a length of metal with a round or square cross section, created by continuous casting or extrusion). Such a film acts to reduce the frictional heat generated during the operation. The lubricant is expected to prolong the life of the die or tool, reduce energy requirements, and produce a smooth, stain-free surface of the metal article.
- High viscosity oils are preferred as the loads increase.
- In severe operations, an extreme pressure additive needs to be added.
In certain nonferrous metalworking applications, polybutenes have a number of advantages over mineral oils when used as a lubricant.
- PIB is non-toxic therefore where applications (of which there are many) place the operator in close proximity to the metalworking machine, the health risks are reduced.
- PIB contains no sulphur no nitrogen species = no staining of the metal.
- PIB produces no carbon deposit after decomposition by depolymerisation at temp. > 300°C so no attack to the metal (brazing, welding, etc).
- PIB has a diverse viscosity range so covers all area of metal production viscosity oils.
- PIB has good storage capabilities therefore no biodegradation.
The most important quality is that polybutenes decompose cleanly and totally at high temperature so they will avoid staining and not leave carbon deposit on the metal article
Metal rolling fluids:
In cold rolling of aluminium sheet or foil, a lubricant is used to reduce the friction between the rollers and the metal sheet.
Some manufacturers avoid the staining from the mineral oil used during the annealing of aluminium by replacing it partially or totally with polybutenes.
In hot rolling of aluminium sometimes the use of an emulsified lubricant based on polybutenes of higher viscosity as Polybut 200 can be used.
Oil leaks, based on polybutenes, that contaminate the rolling oil or metal sheet do not stain because they will decompose totally at annealing temperatures.
Tube drawing: polybutenes can be useful in tube drawing. At an annealing temperature of 550°C to 600°C used for copper tubing, the polybutene is removed quickly and completely from the surface of the metal.
Polybutenes can also be used in cutting oils, anti-corrosion, forging, welding, casting, ironing.
The main purpose is always the lubrification quality together with the total decomposition after burning without residue.