ISPOKESVIAN
Serving the Grease Industry Since 19.33
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VOL. 77, NO. 2, MAY/JUNE 2013
The 80th Annual Meeting
Highlights
Authors and Abstracts
How Friendly are Bio Based
Greases with other Greases?
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NLGI
How Friendly Are Bio-Based Greases with Other Greases?
Dr. Anoop Kumar and Bill Mallory
Royal Mfg Co. LP, 516 s, 25thW Ave., Tulsa, 74127, Oklahoma, USA
Presented at NLGI's 79th Annual Meeting, June, 2012, Palm Beach, Florida, USA
1. Introduction
he applications of lubricants
based on vegetable oils/animal
fats were known to mankind since
our ancient past and continued to
be used until the 19th century when
they were suddenly replaced by
mineral oil, and to a lesser extent,
by synthetic oil based lubricants
and greases [1-2]. These mineral
oil based and/or synthetic oil based
greases have continued to dominate even today. The NLGI 2010
Grease Production Survey indicates
over 2.3 billion lbs. of total worldwide grease volume were mineral
oil based greases which dominated
by about 93%, followed by synthetic and semi-synthetic oil based
greases, or about 3% each. Biobased greases found their entry for
the first time in this survey, though
only about a 1% market share [3].
Lubricating grease based on oils
from vegetable sources has been
reported as early as the 1940's,
however, their practical applications appear to have been reported
in the 1960's [4, 5]. The usage of
bio-based greases has been pretty
spotty since then, until recently.
The main reasons for their limited
applications appear to be their
limited performance, high price and
lack of support from environmental/
governmental agencies. More
recently, growing environmental
consciousness, drive for products
based on renewable sources, legislative compliances, etc., once again
revived bio-based greases. The
further advancement in base oil
chemistry and processes coupled
with additive chemistry to improve
the performance of these bio-based
fluids has further provided support
for their growth. Consequently, more
and more lubricating greases based
on different base oils viz., canola oil,
rapeseed oil, soybean oil, sunflower
oil, castor oil, synthetic esters, etc.,
have recently been reported from
different parts of the world. These
bio-based greases have increasingly
found applications in various industries like agriculture, forestry, mining,
water treatment/sewage treatment,
off shore, railroad, automotive applications, etc. [6-10]. As the majority of lubricating greases presently
being used are mineral oil based,
it is likely that these vegetable oil
based greases, possibly, are going
to replace mineral oil based greases
or, to a lesser extent, by synthetic oil
based greases.
The compatibility of greases with
one another is a very important
property that plays a vital role in
actual applications like centralized
lubrication systems and the applications where complete cleaning or
replacement of existing grease is
very difficult. If two greases are not
compatible with each other, it is likely
that the mixed grease changes its
- 34
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VOLUME 77, NUMBER 2
physical or chemical property and
may lead to the premature failure of
bearing/equipment. Compatibility
of greases also plays a crucial role
while manufacturing, as complete
cleaning of the manufacturing vessel/kettle, filling and finishing line is
extremely difficult. If two greases
are not compatible, and one is produced over the other, it is possible
the quality of fresh grease added
later may be adversely affected.
The incompatibility of lubricating
greases is well known to the industry and compatibility studies are well
documented and reported [11-12].
NLGI and others have published
grease compatibility charts which
indicate the compatibility of different
types of thickeners [13]. Until very
recently, these studies were limited
to different types of thickener systems however nothing significant
on the influence of base oil on the
compatibility has been reported.
Influence of base oil on the compatibility appears to be relevant,
considering the fact that finished
lubricating greases consist of over
80% of base oil itself and does influence end use properties. These
studies become more significant
when considering the change over
from a mineral oil based grease, to
a bio-based grease as mineral oils
primarily consist of hydrocarbons,
whereas bio-based oils are triglycerides of long chain fatty acids.
NLGI
In view of this, compatibility studies
of greases made in different base
oils having the same type or different type of thickeners have been
recently reported by this author [14].
However, these preliminary studies
were limited to the greases having
no additives and no effort was made
to study the compatibility of fully formulated greases. Lou Honary et.al ,
has also recently reported compatibility studies on soy based greases
[15], where it was reported that fully
formulated soy based greases were
found to be compatible with other
greases. In our present study, efforts
have been made to investigate the
effect of canola oil based greases,
both with and without additives,
with other commercially available
mineral and synthetic oil based
greases. Some interesting results
of these investigations have been
covered in this paper.
Grease 1 and Grease 2
50:50 Mixtures
2. Experimental:
The protocol for evaluating the
compatibility of various greases,
have been described in the ASTM D
6185-10 test method [16] and
therefore the compatibility studies in
this paper were carried out based
on this test method. The ASTM-D
6185-10 test method delineates
two stages of testing requirements.
The first one is primary (mandatory) testing and the other one is
secondary (non-mandatory) testing.
As per method, binary mixtures in
10:90, 50:50 and 90:10 ratios are
prepared by physical mixing. These
mixtures along with neat greases
are tested first for primary testing
of less than the repeatability of the
test method used to evaluate the
property.
Accordingly, the binary mixtures
of greases in ratios (50:50; 10:90
and 90:10) are prepared manually
by physical mixing, by spatula on
a flat plate surface until a uniform
mixture emerges. The 100:0 ratios
indicates neat grease and 50:50
ratio indicates 50% of one grease
and 50% of the other grease with
the tolerance limits of ±1 %. The
neat greases were also subjected
to spatulating before testing, to
make the experimental conditions
identical. It was interesting to note
that there was a fall in the dropping
point of neat greases after spatulating, as compared to the undisturbed grease. The mixtures were
tested for all primary tests irrespective of failure and as per option 1
shown schematically in Figure 1.
requirements. These primary tests
to be conducted are dropping point
by ASTM D 566 (or ASTM D 2265),
shear stability (100,000 strokes
worked penetration) by ASTM D 217
and storage stability at elevated
temperatures (change in 60 strokes
penetration) by ASTM D 217 test
method. As per the method, the
mixtures passing all three primary
tests, a secondary (non-mandatory)
testing protocol is also suggested.
Either sequential or concurrent testing is proposed by the method until
the first failure. If any of the mixtures
fail in any of the primary tests, the
greases are declared incompatible.
If all the mixtures pass the three
primary tests, the greases are considered compatible. The greases are
considered borderline compatible
if properties or performance of the
mixture is poorer than those of the
two neat greases, but by an amount
Worked Penetration
After 100,000 Strokes
Dropping
Point
Elevated - Temperature
Storage Stability
10:90 and 90:10
Grease Mixtures
Worked Penetration
After 100,000 Strokes
Dropping
Point
High-Temperature
Storage
4
Secondary Compatibility Tests
—
35 -
NLGI SPOKESMAN, MAY/JUNE 2013
Figure 1
NLGI
The vegetable oils used in these studies were commercially available technical grade canola oil. Properties
of the canola oil are listed in Table 1. Mineral base oils
used for making these greases are either paraffinic
and /or naphthenic oils. The thickeners selected for
making vegetable oil based greases were of three
types, namely lithium complex, aluminum complex and
lithium-calcium mixed based. Other mineral oil based
greases prepared for studying compatibility with vegetable oil based greases were lithium, lithium complex,
aluminum complex, calcium sulfonate complex, and
lithium-calcium mixed base greases and contain performance EP-AW, Anti-oxidant, rust inhibitors, tackifier/
viscosity modifiers, etc. All the bio-based grease samples were prepared in a lab and the mineral or synthetic
oil based greases used in these studies are commercial
plant manufactured greases. All neat and mixtures were
tested as per standard ASTM test methods. The storage stability of the samples was tested according to
Federal Test Method 791C, Method 3467.1 at 120 ± 3°C
(248 ± 3°F) for 24 ± 1/4 h instead of 70 ± 1/4 h. The reason for this deviation is that vegetable oils indicated
faster deterioration at elevated temperatures for prolonged periods of time.
3.1 Compatibility of Bio-Based Aluminum
Complex Grease (No Additives) with
other Aluminum Complex Greases:
The bio-based aluminum complex grease (Grease-1)
is prepared in canola oil (Table-1) but does not contain
any additives. Its compatibility has been studied with
Grease-2 (aluminum complex grease prepared in
naphthenic oil and containing no additives). All grease
samples including neat greases were tested for
mechanical stability (worked penetration after 10,000
strokes), elevated temperature storage stability (Federal
Test Method 791C, Method 3467.1) and dropping
point (ASTM D 2265). Although, the ASTM D 6185-10
method describes that mechanical stability of greases
to be tested after 100,000 strokes whereas these samples were tested for only 10,000 strokes, as aluminum
complex greases, in general, are tested for only 10,000
strokes. These penetrations after 10,000 strokes and
elevated temperature storage stability (Figure-2 (a))
clearly indicate that the penetrations of all mixtures
fall'within the penetration values of neat Grease-1 and
Grease-2. The dropping point of Grease-1 was 276°C
and that of Grease-2 was + 288°C (Table 3). The dropping points of all binary mixtures fell within the dropping points of neat greases. Therefore, Grease-1 and
Grease-2 may be considered as compatible. Grease-1
was also tested for compatibility with Grease-3.
Grease-3 is aluminum complex grease prepared in
3. Results and Discussion:
NLGI defines incompatibility as: "two greases show
incompatibility when a mixture of two products shows physical or service performance,
which are markedly inferior to those of either
of the greases before mixing. The properties
Serial #
or performance inferior to one of the prod1.
ucts and superior to the other, may be due to
simply mixing, and would not be considered
as evidence of incompatibility." As per ASTM
6185-10 primary test protocol, the properties
2.
to be tested are mechanical stability (pene3.
tration after 100,000 strokes), dropping point
4.
and storage stability at high temperatures.
5.
Therefore, these properties have been tested
6.
for neat as well as binary mixtures. In addition
to these, roll stability and weld load has also
7.
been tested for some mixtures.
8.
Table 1
Typical Characteristics of Canola Oil
Property
Viscosity
Method
Data
ASTM D 445
40°C, cSt
35.36
100°C, cSt
8.07
Viscosity Index
ASTM D 2270
Specific Gravity
213
0.91
C.O.C. Flash Point, °C (°F)
ASTM D 92
340 (644)
Smoke Point, °C (°F)
AOCS Cc 9a-48
224 (435)
Fire Point, °C (°F)
ASTM D 92
362 (684)
Pour Point, °C (°F)
ASTM D 97
-18 (0)
Acid Number
ASTM D 974
< 0.10
-36VOLUME 77, NUMBER 2
NLGI
within the repeatability of test method (ASTM D 217).
The deviation by 5 units in a mechanical stability of
50:50 mixtures of Grease-1 and Grease-5, which is
within the repeatability of the test method, indicate that
Grease-1 and Grease-5 have borderline compatibility.
This borderline compatibility is due to a penetration
change after 10,000 strokes, and was further confirmed
by testing roll stability after 2 hrs. for neat Grease-1 and
Grease-5. Roll stability data of 50:50 mixture shows
penetration 341, which is 6 units more than Grease-1.
Similarly, compatibility of Grease-1 with Grease-6
was studied and penetration test results are shown in
Figure 3 (b). Grease-6 is an aluminum complex grease
prepared in naphthenic-paraffinic blend oil (VG 150)
and contains 3.0% antimony dialkyldithiocarbamate,
1% zinc dialkyldithiophosphate, 1% fatty acid derivative
of 4,5-dihydro-1 H imidazole, and 1% alkylated diphenylamine. Mechanical stability (penetration after 10,000
strokes) of 50:50 mixtures of Grease-1 and Grease-6
is higher by 4 units (349) than softer grease i.e.,
Grease-1. This was further confirmed by running roll
blend of group II and Group I paraffinic oil and does not
contain any additive. The penetration test results have
been shown in Figure 2 (b).
Figure 2 (b) indicates that worked penetration after
10,000 strokes, and worked penetration after elevated
temperature storage stability of blends, fall within penetration limits of neat Grease-1 and Grease-3. The
dropping point of mixtures were found to be within the
limits of the dropping point of Grease-1 and Grease-3
and thus considered compatible. The compatibility of
Grease-1 was also studied with Grease-4 (prepared in
8 cSt polyalphaoliffins oil and no additives). Like
Grease-3 worked penetration after 10,000 strokes,
elevated temperature storage stability and drop points
were found to be well within the limits of the two neat
greases (Table 3). Based on these test results, it may
be inferred that bio-based aluminum complex grease
(Grease-1), having no additives is compatible with other
aluminum complex greases having no additives, and
prepared in naphthenic oil (Grease-2), blend of group II
and group I (Grease-3) and synthetic PAO oil (Grease-4).
In order to study the influence of additives on
the compatibility of bio-based aluminum complex
grease, Grease-1 was studied with other aluminum
complex greases having different performance additives. Grease-5 is prepared in naphthenic base oil
and contains additives (Table 3). Worked penetrations
of Grease-1 and Grease-5 mixtures were found to
be within penetration range of the two neat greases.
However, worked penetration of the 50:50 mixture was
found to be 340, 5 units higher than Grease-5 which is
--IF— ET St. Stability
—4— 10 K Pen
340
320
300
,s
280
o.
260
240
0%
50%
10%
90%
% of Grease 2 mixed in Grease 1
Figure 2(a)
••■•••••• 10 K Pen
-
Penetration after mixing Grease-2 with Grease-1
ET St. Stability
ET St. Stability
10 K Pen
340
0
320
3
a
280
260
0%
0A
10%
50%
90%
10%
50%
90%
% of Grease 4 mixed in Grease 1
100%
% of Grease 3 mixed in Grease 1
Figure 2(c) - Penetration after mixing Grease-4 with
Grease-1
Figure 2(b) - Penetration after mixing Grease-3 with Grease-1
MOW
- 37
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NLGI SPOKESMAN, MAY/JUNE 2013
1111111w
110011
NLGI
Table 2
Properties of Test Greases
Grease #
Details
Grease-1
Aluminum complex grease prepared in canola oil and do not contain any additives
Grease-2
Aluminum complex grease prepared in naphthenic oils (VG 150) and do not contain any additives
Grease-3
Aluminum complex grease prepared in blend of group II and paraffinic oil (VG 150) and do not
contain any additives
Grease-4
Aluminum complex grease prepared in synthetic oil (PAO 8) and do not contain any additives
Grease-5
Aluminum complex grease made in naphthenic oil (VG 150) and contains 4.0% blend of antimony
dialkyldithiocarbamate and sulfurized isobutylene) , 1% fatty acid derivative of 4,5-dihydro-1 H
imidazole and 0.5% OCP polymer
Grease-6
Aluminum complex grease made in naphthenic-paraffinic blend oil (VG 150) and contains 3.0%
antimony dialkyldithiocarbamate, 1% zinc dialkyldithiophosphate, 1% fatty acid derivative of
4,5-dihydro-1 H imidazole, 1% alkylated diphenylamine.
Grease-7
Aluminum complex grease prepared in paraffinic oil (VG 150) and contains 2.0% antimony
dialkyldithiocarbamate, 1% zinc dialkyldithiophosphate, 1% fatty acid derivative of 4, 5-dihydro-1 H
imidazole and 5% blend of molybdenum disulphide and graphite
Grease-8
Lithium Complex Grease prepared in Naphthenic oil (VG 150) and do not contain any additives
Grease-9
Lithium complex prepared in Blend of Naphthenic-Paraffinic oil (VG 220) and contains 3.5% blend
of antimony dialkyldithiocarbamate and zinc dialkyldithiophosphate, 1% fatty acid derivative of 4,
5-dihydro-1 H imidazole and 0.5% OCP polymer
Grease-10
Lithium complex prepared in naphthenic Oil (VG 460) and contain 5.0% blend of antimony dialkyldithiocarbamate, zinc dialkyldithiophosphate and sulfurized isobutylene , 1% barium sulfonate,
1% alkylated diphenylamine and 1% OCP polymer
Grease-11
Lithium complex prepared in PAO 8 and contain 3.0% blend of sulfurized isobutylene and zinc
dialkyldithiophosphate, 1% barium sulfonate, 1% alkylated diphenylamine
Grease-12
Aluminum complex grease prepared in canola oil and contains 4% blend of calcium carbonate,
graphite, 3 blend of % Ashless polysulfide and sulfur-phosphorous-nitrogen containing EP-AW
additive
Grease-13
Lithium Complex grease prepared in canola oil and do not contain any additives
Grease-14
Calcium sulfonate complex grease prepared in naphthenic-paraffinic blend oil (VG 220) and
also contain 1% alkylated diphenylamine, 3% calcium carbonate and 0.5% ethylene-propylene
co-polymer.
Grease-15
Lithium complex grease prepared in canola oil and contains, 3.5% blend of Ashless polysulfide and
sulfur-phosphorous-nitrogen containing EP-AW additive and 2% bio-based tackifier
Grease-16
Lithium-calcium grease prepared in canola oil and contains, 3.0% blend of Ashless polysulfide and
sulfur-phosphorous-nitrogen containing EP-AW additive, 1% rust inhibitor and 2.5% bio-based
tackifier
Grease-17
Lithium-Calcium base grease prepared in naphthenic-paraffinic type base oil (VG 460) and contain
3.0% blend of antimony dialkyldithiocarbamate and zinc dialkyldithiophosphate, 1% fatty acid
derivative of 4, 5-dihydro-1 H imidazole and 0.5% ethylene-propylene co-polymer
- 38 VOLUME 77, NUMBER 2
NLGI
Table 3
Compatibility: Bio-Based Aluminum Complex Grease
(With and Without Additives) with Other Greases (With and Without Additives)
A. Compatibility: bio-based aluminum complex grease (without additives) with other aluminum greases
(without additives)
Grease Blend / Property
Blend Ratio
Grease-1 : Grease -2
100:0
90:10
50:50
10:90
0:100
DP Dropping Point, °C
276
278
+288
280
+288
Grease 1 : Grease 3
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
277
275
272
271
271
0:100
262
-
-
Grease 1 : Grease 4
100:0
90:10
50:50
10:90
Dropping Point, °C
277
275
263
268
Grease 1 : Grease 5
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
275
280
+288
279
280
Grease 1 : Grease 6
100:0
90:10
50:50
10:90
0:100
Dropping Point,°C
-
-
-
-
-
-
275
276
279
274
280
Grease 1 : Grease 7
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
278
275
272
270
265
Grease 1 : Grease 8
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
282
260
251
263
267
Weld Load, kg
160
-
-
-
-
-
-
-
-
Grease 1 : Grease 9
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
282
263
241
252
259
Weld Load, kg
160
180
315
315
400
-
-
Grease 1 : Grease 10
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
282
248
216
239
266
Weld Load, kg
160
225
315
400
500
-
-
Grease 1 : Grease 11
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
282
237
230
219
254
Weld Load, kg
160
225
225
250
315
-
-
B. Compatibility: bio-based aluminum complex grease (with additives) with other greases (with additives)
Grease-12 : Grease- 5
100:0
90:10
50:50
10:90
0:100
DP Dropping Point, °C
240
252
263
269
280
Weld Load , kg
400
315
315
315
315
Grease 12 : Grease 9
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
240
238
220
236
253
-
-
400
400
315
400
400
Grease 12 : Grease 10
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
246
240
216
253
266
Weld Load, kg
-
-
400
400
400
400
500
Grease 12 : Grease 11
100:0
90:10
50:50
10:90
0:100
Dropping Point, °C
246
243
235
243
250
Weld Load, kg
-
-
- 39 NLGI SPOKESMAN, MAY/JUNE 2013
NLGI
Grease-8, and do not have any additives. Though weld
load is not included in the primary test protocol of the
ASTM D 6185-10 test method, this test was considered worthwhile as these lithium complex greases are
EP (extreme pressure) type greases, and the effect of
mixing with bio-based grease may possibly have influenced this property. Grease-8 was prepared in naphthenic oil and does not contain any additive. Figure 4
(a) indicates that worked penetrations after 10,000,
as well as 100,000 strokes, and elevated temperature
storage stability data of mixtures fall within the limits of
neat Grease-1 and neat Grease-8. On the other hand,
the dropping points of Grease-1 and Grease-8 were
282°C and 267°C respectively, whereas the dropping
point of 90:10, 50:50 and 10:90 blends are 260°C,
251 °C and 263°C, which are lower than the dropping
point of either Grease-1 or Grease-8 (Table 3). This indicates that Grease-1 is not compatible with Grease-8
due to lower dropping points.
Further, the compatibility of Grease-1 with Grease-9
was also studied (Figure 4 (b)), where Grease-9 is lithium
complex grease prepared in a blend of naphthenicparaffinic oil (VG 220) and contains a 3.5% blend of
antimony dialkyldithiocarbamate and zinc dialkyldithiophosphate, 1% fatty acid derivative of 4, 5-dihydro1 H imidazole and 0.5% OCP polymer. Like Grease-8,
mechanical stability (both penetration after 10,000 and
100,000 strokes), elevated temperature storage stability and weld loads of Grease-1 and Grease-9 mixtures
and fall with the limits of neat Grease-1 and Grease-9.
However, the dropping point of the mixtures were
found to be lower than the dropping point of either
greases (Table 3) and therefore inferred incompatible.
A similar trend has been observed between Grease-1
and Grease-10 (Figure 4 (c)) where Grease-10 is
stability tests for blends, and the neat greases where
roll stability tested after 2 hrs. for 50:50 blends, and
were found to be off by 6 units. Whereas, the elevated
temperature storage stability data fell within the limits
of neat Grease-1 and Grease-6. Similarly, the dropping point of the mixtures fell within the dropping point
of Grease-1 and Grease-6 (Table 3). This indicates the
borderline compatibility of Grease-1 and Grease-6.
On the other hand, compatibility data of Grease-1 with
Grease-7 (Figure 3 (c)) indicate that Grease-1 is compatible with Grease-7. Grease-7 is an aluminum complex grease prepared in paraffinic oil (VG 150) and
contains 2.0% antimony dialkyldithiocarbamate, 1%
zinc dialkyldithiophosphate, 1% fatty acid derivative of
4, 5-dihydro-1 H imidazole and 5% blend of molybdenum disulphide and graphite.
Based on the above studies, it may be inferred that
canola oil based aluminum complex grease having no
additives (Grease-1) is found to be compatible with an
aluminum complex greases prepared in mineral oil or
synthetic oil and not having any additives. However,
Grease-1 was found to be borderline compatible with
two out of three aluminum complex greases having
conventional performance additives.
3.2 Compatibility of Bio-Based Aluminum
Complex Grease (No Additives) with
Lithium Complex Greases:
The NLGI compatibility chart indicates that aluminum
complex greases are compatible with lithium complex
greases, therefore in order investigate the effect of biobased aluminum complex grease on the compatibility
of lithium complex greases, this study was undertaken.
Lithium complex greases selected for these studies
meets NLGI GC-LB specification requirements except
10 KPen
10 K Pen
-.9111
10%
50%
ET St. Stab Ilt ■
350
—dr-- Roll Stability —ill— ET St. Stability
2 350
0
«
;,- 300
4
11 310
a.
10 K Pen
ET St. Stability
—a— Roll Stability
270
0%
10%
50%
90%
% of Grease 5 mixed in Grease 1
100%
250
0%
10%
50%
90%
100%
0%
90%
100%
% of Grease 7 mixed in Grease 1
Figure 3(a) — Penetration after mixing of
Grease-5 in Grease-1
% of Grease 6 mixed in Grease 1
Figure 3(b) — Penetration after mixing Grease-6
"
with Grease-1
—1411111111111.11.11111111011111.1111WIMPM111111111111111M
— 40 —
VOLUME 77, NUMBER 2
Figure 3(c) — Penetration after mixing Grease-7
with Grease-1
NLGI
lithium complex prepared in heavier naphthenic Oil
(VG 460) and contains more amounts of additives
than Grease-9. A similar observation has been found
when the compatibility of Grease-1 was studied with
Grease-11 (Table 3), where Grease-11 is a lithium
complex grease prepared in synthetic oil (PAO 8) and
contain a 3.0% blend of sulfurized isobutylene and
zinc dialkyldithiophosphate, 1% barium sulfonate, 1%
alkylated diphenylamine. Though different penetration
values of the blend fall within the values of neat greases
(Figure 4 (d)), the dropping point of the blends fell considerably (Table-3) as compared to either Grease-1 or
Grease-11, indicating the incompatibility. These blends
were also tested for weld load and the results (Table-3)
did not indicate any adverse effect as a result of mixing.
3.3 Compatibility of Bio-Based Aluminum
Complex Grease (With Additives) with
Other Additive Containing Greases:
Grease-12 is aluminum complex grease prepared in
canola oil and contains a 4% blend of calcium carbonate, graphite, 3% blends of ashless polysulfide and
sulfur-phosphorous-nitrogen containing EP-AW additive, and 0.5% bio-based tackifier. Compatibility of
o-10KPen
Grease-12 was first tested with Grease-5, which was
an aluminum complex grease prepared in naphthenic
oil (VG 150) and contains performance additives, as
indicated in Table 2. Figure 5 (a) and Table-3 indicates
that worked penetration after 10,000 strokes, elevated
temperature storage stability, dropping point and weld
load of 90:10, 50:50 and 10:90 mixtures fell within the
limits of neat Grease-12 and Grease-5. Which indicates
that bio-based aluminum complex grease containing
additives (Grease-12) was found to be compatible with
mineral oil based aluminum complex grease containing
additives (Grease-5). To further investigate the compatibility of additized bio-based grease (Grease-12) with
more greases, compatibility studies were conducted
with different additized lithium complex greases.
Compatibility data of Grease-12 with Grease-9 are
tabulated in Table 3 and also depicted in Figure 5 (b)
where Grease-9 is a lithium complex prepared in a
blend of Naphthenic-Paraffinic oil (VG 220) and contains additives (Table 2). Figure 5 (b) indicates that
worked penetration after 10,000 and 100,000 strokes,
elevated temperature storage stability and weld load
of the mixtures fell within the limits of neat Grease-12
and Grease-9. On the other hand, the dropping point of
—a— ET St. Stability
10 K Pen
340
100 K Pen
Penetration
ET St. Stability
30
320
3
300
C
0
280
a-
330
310
C
290
20
260
0%
10%
50%
90%
250
10%
100%
10%
% of Grease 3 mixed in Grease 1
50%
100 %
90%
% of Grease 9 mixed in Grease 1
Figure 4(a) - Mixture Grease-8 with Grease-1
Figure 4(b) - % Mixing of Grease-9 in Grease-1
gill.11.1110011111011111111110111010110.1"
1- 10KPen —48e...100KPen
—
ET St. S7ability
10 K Pen
ir."100 K Pen —X— ET St. Stability
350
0
300x
X
X
X
90%
100%
250
0%
% of Grease 10 mixed in Grease 1
10%
50%
% of Grease 11 mixed in Grease 1
Figure 4(c) - Penetration after Mixing of Grease-10 in Grease-1
Figure 4(d) - Penetration after Mixing of
Grease-11 in Grease-1
- 41 -
NLGI SPOKESMAN, MAY/JUNE 2013
NLGI
meet the penetration, even weld load but do not meet
the dropping point requirements (Table-3) and thus
deemed incompatible. To further validate this observation, compatibility of Grease-12 was tested with a
synthetic oil based lithium complex grease (Grease-11)
containing additives as described in Table-2. Like
Grease-9 and Grease-10, mixtures of Grease-12 with
Grease-11 exhibited lower dropping point (Table-3)
though comparative penetrations appear to be fine
the mixtures was found to be less than either of the neat
greases. Though grease mixtures pass the test criteria
in other tests, lower dropping points of the mixtures indicate that Grease-9 and Grease-12 are not compatible.
Similarly, compatibility data of Grease-12 with
Grease-10 where Grease-10 is lithium complex grease
prepared in a higher base oil viscosity oil (VG 460) and
contains more additives than Grease-9 Figure 5 (c),
indicate that the mixtures of Grease-10 and Grease-12
Table 4
Bio-Based
Lithium Complex Greases
Compatibility:
(With and Without Additives) with Other Greases (With and Without Additives)
C. Compatibility: bio-based lithium complex grease (without additives) with other greases
Blend Ratio
Grease Blend / Property
0:100
10:90
50:50
90:10
100:0
Grease-13 : Grease - 8
263
266
266
250
260
DP Dropping Point, °C
0:100
10:90
50:50
100:0
90:10
Grease-13 : Grease -9
274
267
263
269
250
Dropping Point, °C
0:100
50:50
10:90
90:10
100:0
Grease-13 : Grease -5
271
242
223
248
250
Dropping Point,°C
10:90
0:100
50:50
100:0
90:10
Grease-13 : Grease -14
274
226
259
242
243
Dropping Point, °C
D. Compatibility: bio-based lithium complex grease (with additives) with other greases
0:100
50:50
10:90
90:10
Grease-15 : Grease -8
100:0
266
261
260
260
252
Dropping Point, °C
0:100
10:90
50:50
100:0
90:10
Grease-15 : Grease -9
286
267
263
226
252
Dropping Point, °C
0:100
10:90
50:50
90:10
100:0
Grease-15 : Grease -5
271
211
199
231
252
Dropping Point, °C
0:100
10:90
50:50
90:10
.100:0
Grease-15 : Grease -14
274
211
230
245
252
Dropping Point, °C
E. Compatibility: bio-based Lithium-calcium grease with other greases
0:100
10:90
50:50
90:10
100:0
Grease-16 : Grease- 17
198
201
198
195
DP Dropping Point, °C
191
400
315
315
400
400
Weld Load, kg
0:100
10:90
50:50
90:10
100:0
Grease-16 : Grease -9
252
224
197
204
191
Dropping Point, °C
315
400
315
400
400
Weld Load, kg
10:90
0:100
50:50
90:10
100:0
Grease-16 : Grease -5
271
220
179
185
192
Dropping Point, °C
315
315
315
315
400
Weld Load, kg
0:100
10:90
50:50
100:0
90:10
Grease-16 : Grease -14
271
216
253
192
207
Dropping Point, °C
Weld Load, kg
400
400
400
-42VOLUME 77, NUMBER 2
500
500
Grease-13's compatibility was also studied with
mineral oil based, additized aluminum complex grease
(Grease-5). Worked penetration after 100,000 strokes
and elevated temperature storage stability data of the
mixtures appears to be well within the limits of neat
greases (Figure 6 (c)), whereas the dropping point
(Table 4) of the mixtures (especially 50:50 blend) was
found to be much lower than either of the greases, indicating incompatibility. Compatibility of Grease-13 was
also evaluated with calcium sulfonate complex grease
(Grease-14) with additives. Mechanical stability and
elevated temperature storage stability data of the mixtures (Figure 6 (d)) were found to be within the limits.
However, the dropping point (Table-4) of all the blends
(especially 50:50 blend) was found to be much lower
than neat greases, and thus incompatible. It is therefore
inferred that bio-based lithium complex grease without
any additives, was found to be compatible with both
with/without additives mineral oil based lithium complex
greases, but incompatible with additized mineral oil
based aluminum complex and calcium sulfonate complex greases.
To further validate this observation, compatibility
of bio-based lithium complex grease (Grease-15), prepared in canola oil, having a 3.5% blend of Ashless
(Figure 5 (b)) thus concluded as incompatible. These
studies indicate that additized bio-based aluminum
complex grease was found to be compatible with
additized mineral oil based aluminum complex grease,
but incompatible with additized mineral oil, and also
synthetic oil, based lithium complex greases.
3.4 Compatibility of Bio-Based Lithium
Complex Greases with Other Greases:
Another class of bio-based grease studies, is lithium
complex greases. Grease-13 is a lithium complex
grease prepared in canola oil and does not contain any
additives. Its compatibility was first studied with mineral
oil based lithium complex grease that does not contain
any additives (Grease-8) and the test result is depicted
in Figure 6 (a) and also in Table-4. Test data indicate
that worked penetration after 100,000 strokes, elevated
temperature storage stability and dropping point of the
mixtures, fall within the limits of neat Grease-13 and
Grease-8, and are therefore considered compatible.
The compatibility of Grease-13 was further studied with
lithium complex grease (Grease-9), that contains additives as described in Table 2. Figure 6 (b)) and Table 4,
data analysis would confirm that Grease-13 and
Grease-9 are compatible.
S8
1.)
■Sl■
ET St. Stability
100 K Pen
a8
50%
10%
ct
100 3/4
90%
% of Grease 12 mixed in Grease 5
370
35
33
310
29
270
250
0%
350
a90%
50%
100%
Figure 5(b) - Penetration after Mixing of
Grease-12 with Grease-9
11111111111MMINIIIIIIIIMPUMMInir-
10%
300
33
295
310
0
290
290
270
28
250
90%
100 %
% of Grease 12 mixed in Grease 11
Figure 5(d) - Penetration after Mixing
Grease-12 with Grease-11
71111111111MMOMMIIMIMMIIIIIIMINms*
0%
10%
50%
90% 100%
% of Grease 13 mixed in Grease 8
Figure 6(a) - Penetration after Mixing of Grease-13
in Grease-8
- 43 NLGI SPOKESMAN, MAY/JUNE 2013
10 0 %
90%
Figure 5(c) - Penetration after Mixing Grease-12 in
Grease-1 0
—
Er St. Stability
50%
% of Grease 12 mixed in Grease 10
a— 100 K Pen
—II— ET St. Stability
370
305
350
50%
250
0%
—tr.-- 100 K Pen —X— ET St. Stability
370
350
10%
290
270
10%
10 K Pen
250
0%
330
310
-
-a--
370
0
% of Grease 11 mixed in Grease 9
Figure 5(a) - Penetration after Mixing
Grease-12 with Grease-5
ili■•• 100 K Pen
11k— ET St. Stability
—a— 100 K Pen
370
350 •
330
31
270 •
250
0%
10 K Pen
10 K Pen
Er St. Stability
Penetration
••■••••■ 10 KPen
29
270 •
250
0%
10%
50%
90%
% of Grease 13 mixed in
100%
Grease 9
Figure 6(b) - Penetration after Mixing of
Grease-13 in Grease-9
NLGI
and Table-4. It is concluded that bio-based lithium
complex grease having EP-AW additives, was found to
be compatible with mineral oil based lithium complex
grease (no-additives), but incompatible with mineral oil
based additized lithium complex, aluminum complex
polysulfide and sulfur-phosphorous-nitrogen containing
EP-AW additive, and 2% bio-based tackifier, was studied with other greases. Figure 7 (a) and Table-4 indicate
that Grease-15 with Grease-8, which is a mineral oil
based lithium complex grease having no additives, are
compatible. On the other hand, compatibility test data
and calcium sulfonate complex greases.
of Grease-15 with Grease-9 (mineral oil based lithium
complex grease containing additives), indicate that
100,000 strokes worked penetration, elevated temperature storage stability (Figure 7 (b)) and weld load, fall
within the limits of neat greases, but the dropping point
of the 50:50 mixture was found to be much less than
any individual neat grease, and therefore incompatible.
Compatibility data (Figure 7 (c) and Table-4) of
Grease-15 with additized mineral oil based aluminum
complex grease (Grease-5), indicate that, though the
100,000 strokes worked penetration, elevated temperature storage stability and weld load fall well with
the limits of individual neat greases, the dropping
point of all the mixtures were found to be lower than
that of either of the neat greases. The similar trend
was observed when compatibility of Grease-15 was
tested with additized calcium sulfonate complex grease
(Grease-14) and test data are depicted in Figure 7 (d)
3.5 Compatibility of Bio-Based LithiumCalcium Greases with Other Greases:
Another type of bio-based grease considered for these
studies, are additized bio-based lithium-calcium grease
(Grease-16). Grease-16 is lithium-calcium grease
prepared in canola oil and contains a 3.0% blend of
Ashless polysulfide, sulfur-phosphorous-nitrogen containing EP-AW additive, 1% rust inhibitor and 2.5%
bio-based tackifier.
Compatibility of Grease-16 was first studied with
mineral oil based additized lithium-calcium grease
(Grease-17). The test data (Table 4 and Figure 8 (a))
indicate that the values of the test results of all the
mixtures fall within the limits of Grease-16 and
Grease-17 thus considered compatible. Grease-16
was further tested with Grease-9, which is a mineral oil
100 K Pen
100 K Pen —rte ET St. Stability
4
— —
•■Aii■
ET St. Stability
350
350
Er St. Stability
100 K Pen
350
a
1'3 300
300
300
2
c!!
250
iu
a250
250
0% 10% 50% 90% 100%
0% 10%
% of Grease 13 mixed in Grease 5
50%
0%
90% 100%
10%
Figure 6(c) - Penetration after Mixing
Grease-13 with Grease-5
Figure 6(d) - Penetration after Mixing of
Grcasc-13 with Grease-14
50%
Figure 7(a) - Penetration after Mixing
Grease-15 with Grease-8
10 K Pen
ET St. Stability
Penetrat ion
310 -
ro
290
°- 290
250
0% 10% 50 1. 90% 100%
% of Grease 15 mixed in Grease 9
Figure 7(b) - % Mixing of Grease-15 in
Grease-9
y
3304.41
-
330 c
V 310
aci
—111— ET St. Stabili
350 -
350 -
300 -
100%
ET St. Stability
—0— 10 K Pen
100 K Pen
90%
% of Grease 15 mixed in Grease 8
% of Grease 13 mixed in Grease 14
20
0%
10%
50%
90%
100%
20
0%
% of Grease 15 mixed in Grease 5
Figure 7(c) - Penetration after Mixing Grease-15 in
Grease-5
- 44 —
VOLUM E 77, NUMBER 2
10%
50%
90%
100%
% of Grease 15 mixed in Grease 14
Figure 7(d) - Penetration after Mixing
Grease-15 with Grease-14
NLGI
additized lithium complex grease. Worked penetration
after 100,000 strokes, elevated temperature storage
stability (Figure 8 (b)), dropping point and weld load
data (Table-4) of the mixtures tested, indicate that the
two greases are compatible.
However, when Grease-16 was tested with
Grease-5, which is an additized mineral oil based aluminum complex grease, it exhibited incompatibility in
terms of mechanical stability, elevated temperature
storage stability and dropping point (especially 50:50
blend) (Figure 8 (c) and Table 4). Compatibility of
Grease-16 was also tested with Grease-14, a mineral
oil based additized calcium sulfonate grease. The test
data of the mixtures (Figure 8 (d) and Table 4) indicate
that the worked penetration, after 100,000 strokes,
elevated temperature storage stability and dropping
points of all the mixtures, and fell within the limits of
neat Grease-16 and Grease-14. Based on the test data
as described in Table-4, it can be concluded that biobased lithium-calcium grease, containing performance
additives, is compatible with mineral oil based additized
lithium-calcium, lithium complex and calcium sulfonate
complex greases, but incompatible with mineral oil
based, additized aluminum complex grease.
have so far been made to study compatibility of these
greases prepared in other bio-fluids. It has been interesting to note that canola oil based aluminum complex
grease, without any additives, was found to be compatible with mineral oil or synthetic oil based aluminum
complex greases, having no additives, but found to be
borderline compatible with two out of three aluminum
complex greases, having additives and prepared in mineral/synthetic oils. However, the same grease was found
to be incompatible with mineral/synthetic oil based
lithium complex greases, having performance additives.
Additionally, additized canola oil based aluminum complex grease, was found to compatible with additized,
mineral oil based aluminum complex grease, but incompatible with additized lithium complex greases.
These compatibility studies were further extended to
canola oil based lithium complex grease. Test results
indicate that canola oil based lithium complex grease,
without any additives was found to be compatible with
mineral oil based lithium complex grease, having no
additives and also with additives; however was found
to be incompatible with additized, mineral oil based
aluminum and calcium sulfonate greases. When the
—Ai— ET St. Stability
—••■• 10 K Pen
320 •
300 Penetration
4.0 Conclusions:
The compatibility of canola oil based aluminum complex, lithium complex and lithium-calcium greases,
either with or without additives, was studied with different aluminum complex, calcium sulfonate complex,
and lithium complex greases, prepared in different base
oils and containing different additives. These studies are
limited to canola oil based greases, and no attempts
280 -
240
220
0%
10%
50%
Grease-17
330
330
5
310
310
290
290
280
a
350
350
300
e_
260
e_
270
250
240
ET St. Stability
10 K Pen
K Pen —A-- ET St Stability
320
100%
Figure 8(a) - Penetration after Mixing Grease-16 with
—U-10 K Pen —a— ET St. Stability
340
0
90%
% of Grease 16 mixed in Grease 17
270
250
230
0%
220
10%
50%
90%
100%
230
0%
0%
10%
50%
90%
100%
10%
50%
90%
% of Grease 16 mixed in Grease 5
% of Grease 16 mixed in Grease 14
% of Grease 16 mixed in Grease 9
Figure 8(b) - Penetration after Mixing
Figure 8(c) - Penetration after Mixing
Grease-16 with Grease-5
Grease-16 with Grease-9
- 45 -
NLGI SPOKESMAN, MAY/JUNE 2013
Figure 8(d) - Penetration after Mixing of
G rease- 1 6 in Grease-14
100%
NLGI
compatibility of additized canola oil base lithium complex grease, was studied with mineral oil based lithium
complex grease, without any additives, and was found
compatible. However, the same grease was found to
be incompatible with additized lithium complex, aluminum complex and calcium sulfonate complex greases.
Interestingly, canola oil based lithium-calcium grease,
containing performance additives, was found to be
compatible with additized lithium complex and calcium
sulfonate complex greases, although incompatible with
additized aluminum complex greases.
It appears from these studies that the properties,
especially dropping points, of the blends of two greases
are considerably influenced and dependent on the
type of thickener and amount of additives present in
either finished grease; however there was no significant
impact on penetrations. These studies could not establish any generalized trend, and therefore, more elaborate studies may be necessary to investigate further.
[5] McNichol, M. A., "A Co-op First Rapeseed Oil
Grease" NLGI Spokesman, Vol. 24(10), 1961, pp.
408-409.
[6] Honary, L., "Performance Characteristics of
Soybean Based Greases Thickened with Clay,
Aluminum Complex and Lithium" NLGI Spokesman,
Vol. 65(8), 2001, pp. 18-27.
[7] Kumar, A., et al., "Eco-Friendly Titanium Complex
Grease" NLGI Spokesman, Vol. 61(8), 1997, pp.
22-28.
[8] Kieke, M. D. and Klein, R. J, "Earth Friendly
Vegetable Oil Based Greases Thickened with
Organophilic Clay" NLGI Spokesman, Vol. 67(9),
2003, pp. 14-16.
[9] Hocine, F., Medrano, A. and Cisler, B.,
"Biodegradable Open Gear Lubricant" NLGI
Spokesman, Vol. 67(12) 2004, pp. 121-135
[10] Stempfel, E. M. and Baumann, M., "Environmentally
Acceptable Lubricants in Railway Applications"
Eurogrease, September/October, 2004, pp. 19-34.
Acknowledgement:
[11] Myers, E. H., "Incompatibility of Greases" NLGI
Spokesman, Vol. 47(4), 1983, pp. 24-32.
The authors wish to acknowledge grease plant personnel, especially Monte Walton, for the assistance in
arranging the samples and other inputs for these studies. Authors are also thankful to the management of
Royal Mfg. Co. LP for all necessary assistance in carrying out this work and granting permission to report
such work.
[1 2] Mistry, A., "Grease Compatibility Revisited" NLGI
Spokesman, Vol. 64(10), 2001, pp. 24-30.
[13] Boner, C. J., "Modern Lubricating Greases"
Scientific Publishing (G.B.) Ltd, Shropshire,
England, 1976, pp. 2.20.
[14] Kumar, A., et al., "Compatibility of Vegetable Oil
Based Greases with Different Mineral Oil Based
Greases" Journal of ASTM International, Vol. 8.
No. 9, 2011.
References:
[1] Boner, C. J., "Manufacturing and Applications of
Lubricating Greases" Reinhold Publishing Corp.,
430 Park Ave. NY, 1954, pp. 136-138.
[15] Honary, L., "A Study of Compatibility of Fully
Formulated Bio-based and Conventional Greases"
presented at 78th NLGI Annual Meeting, Palm
Desert California, June 2011.
[2] Polishuk, A.T., "A Brief History of Lubricating
Greases" Llewellyn & McKane Inc. PA, 1998, pp.
35-72
[16] ASTM Standard D6185-10, "Standard Practice
for Evaluating Compatibility of Binary Mixtures
of Lubricating Greases" ASTM Annual Book of
Standards, 2010, Vol. 05.03 ASTM International,
West Conshohocken, PA.
[3] NLGI, "Grease Production Survey Report" Kansas
City, Missouri, 2010.
[4] Nicholaichuk, M. P., "Field Testing and Commercial
Experience with Lithium Rapeseed Grease" NLGI
Spokesman, Vol. 35(12), 1962, pp. 153-154.
- 46
-
VOLUME 77, NUMBER 2
NLGI
ABOUT THE AUTHORS
Dr. Anoop Kumar - Royal Manufacturing
Co. LP - Anoop received his M.S. in
Chemistry and Ph.D. in Chemistry, 1991,
from Indian Institute of Technology, India.
Currently, he is the Director of R&D for
Royal Manufacturing Co., Tulsa, OK.
Prior to joining Royal, he worked for
Indian Oil Corpora-tion, India. Anoop
has over 17 years experience in the
development of greases and lubricants,
has authored over 60 papers, and has many patents on grease
development. He was instrumental in the formation of the NLGIIndia Chapter and served as Treasurer. He is the recipient of the
UN-WIPO Silver Medal award. He is a life member of the Tribology
Society of India.
Bill Mallory - Royal Manufacturing Co.
LP - Presently CEO and President of
Royal Manufacturing Company. He has
over 50 years of experience in the field
of lubricating oils and greases. Under
his vision and guidance, Royal Mfg. Co.
successfully manufactures almost all
kinds of greases from lithium, sulfonate,
Polyurea, aluminum complex etc. He
developed and improved many grease
formulations and products. He has the credit of designing and
putting up two world class grease plants; one in Tulsa and the
other in San-Antonio. He has played a decisive role in acquiring
Wright Oil Company and Troco Oil Company and consolidating
all companies to one Royal Mfg. Co. LP. Bill is a regular attendee
of industry meetings like NLGI, ILMA, STLE, SAE, etc. His current
interests are bio-based and food grade lubricants.
•
•
Tribotecc
•
-
more than performance
solid lubricants
Reduction of wear
High load capacity
Excellent metal adhesion
For technical assistance please contact
Ron Balmain
at 704 243 0213 or
ron.balmain©tribotecc.com
Superior oxidation resistance
Improvement of friction coefficient
Improvement of high load temperature efficiency
Tribotecc GmbH
A company of Rockwood Holdings. Inc.
Rockwo od
- 47 —
NLGI SPOKESMAN, MAY/JUNE 2013