ILMA Compoundings September 2018 - 32

produces base oils with virtually no contaminants or wax.
In fact, because of the process used to make them and
their properties, Group III base oils are now referred to as
"synthetic." This designation is the result of an advertising
claim challenge made by ExxonMobil (which was known
as Mobil at the time) questioning Castrol's use of the term
with motor oils made with Group III base oils. The National
Advertising Division of the Better Business Bureau decided,
based on the technical data provided by Castrol, that Group
III base oils could also be made by a synthetic process, so
the refined Group III could be designated as synthetic. The
advantages for Group III are similar to Group II, only to a
greater degree. Once again, the hydroprocessing results in
lower viscosity. Group III base oils range in viscosity from
about 3cSt to 8cSt at 100 degrees Celsius.
Since the introduction of Group II (and later Group III) base
oils, there has been a shift in the availability of base oils toward
Group II and growth of Group III. So, what drives these
changes? Why did Group II and Group III grow while Group I
fell in popularity? The answers to these questions are rooted in
the economics of each and in the needs of the market.
The marketplace for base oils is driven primarily by
automotive applications. Globally, about 56 percent of oils
marketed are for automotive applications. That includes
both engine oils and transmission fluids. The twin drivers
of fuel economy and emissions controls dictate lower oil
viscosities. In addition, the increased need for base oil
stability (primarily oxidation) also calls for more stable base
oils. Both of these needs benefit from the use of Group II
and Group III base oils.
Economically, Group I base oil refineries are much older
than Group II or Group III refineries. In addition, the
byproducts of Group I production were difficult to market
and were considered more hazardous. Both of these issues
led to many Group I refineries either being shut down or
upgraded to produce Group II base oils.

SEPTEMBER 2018

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However, Group I base oils fill some important niches thanks
to their heavy neutral and bright stock production. For some
applications (e.g., two-cycle engine oil and certain process oils),
Group I base oils are the optimum material to use. Historically,
Group I base oils are well-suited for grease production.
Besides their obvious automotive applications, Group II
base oils are well suited for use in hydraulic and turbine oils.
Their thermal and oxidative stability properties allow for
longer life and less contaminant formation. Some process oil
applications will also benefit from Group II base oils.
Group III base oils, because of their extreme stability and
low viscosity, are primarily suited for automotive applications. The fact that they can be labeled as synthetic is an
added inducement to use them, since economically they
compare favorably to Group IV and Group V base oils.
One issue that affects both Group II and Group III base
oils is volatility. The most recent automotive engine oil
standards have severe limitations on volatility. When that
is combined with very low viscosity, it becomes necessary
to change the refining of these base oils to gain satisfactory
volatility properties. This results in lower yields, as a larger
percentage of higher-volatility (lower-viscosity) components
must be removed during processing. The resulting oil is typically higher in VI (viscosity index) while lower in volatility
and viscosity. The so-called "Group II+" and "Group III+"
oils are examples of these products. They are almost totally
used in premium engine oils.
Future projections are for increased use of Group II base
oils and for some growth for Group III base oils. It's very
likely that refiners will add Group II and Group III capacity
over the next several years. Automotive needs will continue
to drive engine oil development. Improved transmissions
will also continue to push improvements in transmission
fluids. The introduction and growth of electric vehicles will
not likely have a major impact on this market for at least 20
to 25 years because of the very slow turnover rate of vehicles.
Globally, it looks like the internal combustion engine could
rule well into the second half of the 21st century.
All things considered, the Group I market will become a
specialty niche similar to some of the naphthenic markets
and provide improvements to products that traditionally
were made with naphthenic base oils. Group II has become
the mainstay of the lubricating base oil market and will
continue to grow. Group III will be the ongoing synthetic
for premium use.
Swedberg has more than 50 years' experience in the oil industry and
has been involved with several industry organizations, including STLE,
NLGI, ASTM and SAE, where he was Technical Committee 1 (Engine Oils).
chairman from 1992-96. Swedberg is currently consulting on lubricating
products and additives and is a technical writer.

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ILMA Compoundings September 2018

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