ILMA Compoundings - July 2019 - 31

Figure 2: North American PCMO Demand by SAE Grade
50%
2010

2020

Share, %

40%
30%
20%
10%
0%
0W-20

5W-20

5W-30

additives, hindered phenols and
molybdenum-containing additives.
There were synergies obtained by
using combinations of antioxidants
most likely due to the inhibition of
either the initiation or propagation
steps in the oxidation of the lubricant.
The choice of using combinations of
antioxidants is expected to continue
with the development of ILSAC GF-6. 
Sequence III engine cleanliness can
be controlled with a proper selection
of base stock, viscosity modifier type/
treat rate, antioxidants, detergent
soap and ashless dispersant. This
trend will continue into ILSAC
GF-6. There is a trend among the
major additive suppliers to switch
from chlorine-processed PIBSA/
PAM dispersants to thermal-processed
dispersants. For efficient conversion,
the thermal processing requires a high
preponderance of terminal double
bonds in the polyisobutylene (PIB) to
convert to polyisobutylene succinic
anhydride (PIBSA). Although, from
the patent literature, it appears that
certain iterations of thermal dispersant
offer improved engine cleanliness, the
actual driver for the switch may be for
environmental and safety concerns.
The other point of note with the
development of ILSAC GF-6 has been

10W-30

10W-40

20W-50

Other

the change in viscosity grade demand
over the previous 10-year period that
essentially represents the adjusted timeline for the new category development.
Market demand for low SAE-grade
engine oils like 0W-20 is creating an
increased demand for higher-viscosity
index (VI) base stocks. In the past,
a Group II+ equivalent quality (e.g.,
112 to 116 VI depending on additive
chemistry and finished blending
targets) could be used to formulate SAE
5W-20 and SAE 5W-30 grades. Many
base stock combinations could be considered, including Group II+, Group
II and Group III, Group II and Group
III+, and Group II and Group IV. In
each instance, the amount of Group
II would be balanced to deliver the
target VI while maintaining acceptable
volatility and CCS performance.
Figure 2 represents the change in
the North American PCMO demand
between 2010 and 2020. The significant
growth in SAE 0W-20 demand from
3% to 17% reflects the continuing
need for Group III and Group III+ base
stocks that are required for this SAE
viscosity grade. When GM dexos1™
performance is included, the more
stringent volatility targets create a further
demand for Group III/III+ such that
most GM-approved formulations (SAE

0W-20, SAE 5W-20 and SAE 5W-30 in
particular) are now based essentially on
Group III/III+ base stocks.
So, the road to ILSAC GF-6 has
been an adventure marked with
many changes, delays, side trips and
challenges. The industry as a whole has
remained committed to the category
development, and the result has been
the successful completion of ILSAC
GF-6 with a first license date of May
1, 2020. This represents nearly a
decade of development and a delay of
approximately 64 months from the
original first license date of Jan. 1,
2015. In short, a very lengthy trip. It
also included an intermediate performance specification, API SN-PLUS,
that was introduced May 1, 2016,
to address the immediate need from
OEMs for low-speed LSPI control.
The journey to ILSAC GF-6 has
truly been an adventure, with many
lessons learned along the way. This will
hopefully provide a framework for the
next PCMO category development
(i.e., ILSAC GF-7) with a much
shorter and direct road map.
Henderson is president of K&E Petroleum
Consulting LLC. This article includes
contributions from Rolfe Hartley, Ph.D., of
Sangamon Consulting LLC.

31
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