Field of the invention
The present invention relates to grease compositions, in particular grease
compositions having a reduced environmental impact and exhibiting good extre5 me
pressure and corrosion properties, in particular with respect to metals or metal alloys.
Technical background of the invention
Recent times have seen the increasing significance of environmental problems
on a worldwide scale and the enforcement of protection of the terrestrial biosphere as
10 a major challenge in all sectors of industry. The field of greases is no exception to the
rule, and the risk of pollution of watercourses and soils that is represented in particular
by disposal into the natural environment of base oils, the main ingredients of these
products, means that today progress is expected in respect of these oils, in particular in
the area of biodegradability, for uses which involve the risk of external leakage of
15 greases. At the same time, increasingly powerful machinery is subject to demands
under ever more severe conditions and in addition to biodegradability, for example,
their lubrication products are required to show significant improvements in
performance in terms of extreme pressure and corrosion properties.
The present invention relates to a grease composition that can be used in
20 devices which present a risk of external leakage of grease such as automobiles,
construction machinery or agricultural equipment, while at the same time having a
reduced environmental impact, good performance under extreme pressure and a low
corrosiveness to metals or metal alloys.
Surprisingly, the applicant observed that a grease composition having a
25 combination of at least one sulfurized fatty acid ester, said ester providing a certain
quantity of active sulphur at 150°C according to standard ASTM D1662, and at least one
dimercaptothiadiazole derivative, in a base oil of the polyol ester type, has very good
extreme pressure properties, is not corrosive in particular to metals or metal alloys, in
particular to copper, while having a reduced environmental impact.
30 Brief description of the invention
The invention relates to a grease composition comprising at least one base oil of
the polyol ester type, at least one fatty-acid metal soap, at least one
dimercaptothiadiazole derivative and at least one sulfurized fatty acid ester, the
quantity of active sulphur at 150°C according to standard ASTM D1662 by mass
WO2013087896 3 text for national entry
provided by the sulfurized fatty acid ester with respect to the total mass of grease
composition being greater than or equal to 0.18%.
Preferably, the polyol ester is chosen from neopentylglycol esters,
trimethylolethane esters, trimethylolpropane esters, pentaerythritol esters and/or
dipentaerythritol esters, used alone or in a mixture5 .
Preferably, the composition comprises from 50 to 95% by mass with respect to
the total mass of grease composition of a base oil of the polyol ester type, preferably
from 60 to 90%, more preferentially from 70 to 80%.
Preferably, the dimercaptothiadiazole derivative is chosen from the derivatives
10 of 4,5-dimercapto-1,2,3-thiadiazoles, 3,5-dimercapto-1,2,4-thiadiazoles,
3,4-dimercapto-1,2,5-thiadiazoles, 2,5-dimercapto-1,3,4-thiadiazoles, used alone or in a
mixture.
Preferably, the composition comprises from 0.1 to 5% by mass of
dimercaptothiadiazole derivative with respect to the total mass of grease composition,
15 preferably from 0.2 to 2%, more preferentially from 0.5 to 1%.
Preferably, the sulfurized fatty acid ester is a fatty acid triglyceride and/or a
fatty acid methyl ester, used alone or in a mixture.
Preferably, the composition comprises from 0.5 to 5% by mass of sulfurized
fatty acid ester with respect to the total mass of grease composition, preferably from
20 1 to 4%, more preferentially from 2 to 3%.
Preferably, the fatty-acid metal soap is a simple fatty-acid metal soap,
preferably of lithium or calcium.
Preferably, the fatty-acid metal soap is lithium 12-hydroxystearate.
Preferably, the composition comprises from 1 to 20 % by mass with respect to
25 the total mass of the grease composition of fatty-acid metal soap, preferably from
2 to 15%, preferentially from 4 to 12%.
Preferably, the polyol ester, or the mixture of polyol esters, has a kinematic
viscosity at 40°C, measured according to standard ASTM D 445, comprised between
3 and 2000 cSt, preferably between 10 and 1500 cSt, more preferentially between
30 40 and 500 cSt, even more preferentially between 50 and 200 cSt.
Preferably, the composition has a consistency according to standard ASTM
D217 comprised between 220 and 430 tenths of a millimetre, preferably between
265 and 295 tenths of a millimetre.
Preferably, the quantity of active sulphur at 150°C according to standard ASTM
35 D1662 by mass provided by the sulfurized fatty acid ester, with respect to the total
WO2013087896 4 text for national entry
mass of grease composition, is preferably greater than or equal to 0.19%, preferably
greater than or equal to 0.20%, more preferentially greater than or equal to 0.21%.
Preferably, the composition has a welding load according to standard ASTM
D2596 greater than 315 kg, preferably greater than or equal to 400 kg.
Preferably, the composition has a welding load according to standard D5 IN
51350/4 greater than 300 daN, preferably greater than or equal to 320 daN, more
preferentially greater than or equal to 340 daN, even more preferentially greater than
or equal to 360 daN.
Preferably, the composition has a classification of corrosiveness to copper
10 according to standard ASTM D4048 of 1 or 2.
The invention also relates to the use in a grease composition comprising at least
one base oil of the polyol ester type and at least one fatty-acid metal soap of at least
one dimercaptothiadiazole derivative and at least one sulfurized fatty acid ester, the
quantity by mass of active sulphur at 150°C according to standard ASTM D1662
15 provided by the sulfurized fatty acid ester being greater than or equal to 0.18%, with
respect to the total mass of grease composition, in order to improve the extremepressure
performance according to standards ASTM D2596 and/or DIN 51350/4 of the
grease composition.
The invention also relates to a lubricant composition comprising at least one
20 base oil of the polyol ester type, at least one dimercaptothiadiazole derivative and at
least one sulfurized fatty acid ester, the quantity by mass of active sulphur at 150°C
according to standard ASTM D1662 provided by the sulfurized fatty acid ester with
respect to the total mass of lubricant composition being greater than or equal to
0.18%.
25 Detailed description
Sulfurized fatty acid ester
The grease according to the invention comprises at least one sulfurized fatty
acid ester.
The sulfurized fatty acid esters are obtained by sulphurizing fatty acid esters.
30 Said fatty acid esters are obtained by reaction between one or more fatty acids and
alcohols of all sorts or by transesterification between one or more fatty acid esters and
alcohols of all sorts. By sulfurized fatty acid ester is meant an ester of at least one
sulfurized fatty acid, it being understood that this is usually an ester of a mixture of
sulfurized fatty acids.
WO2013087896 5 text for national entry
The fatty acids that can be used to form the sulfurized fatty acid esters are all
fatty acids comprising from 6 to 24 carbon atoms, preferably from 14 to 22 carbon
atoms, more preferentially from 16 to 20 carbon atoms. Fatty acids comprising
18 carbon atoms are the majority fatty acids, i.e. they are present at a concentration by
mass of at least 50% with respect to the total mass of sulfurized fatty acid est5 er.
The sulfurized fatty acid esters may be sulfurized fatty acid monoesters,
sulfurized fatty acid diesters, sulfurized fatty acid triesters or sulfurized fatty acid
polyesters, used alone or in a mixture.
Preferred sulfurized fatty acid monoesters are C1-C4 alkyl monoesters, such as
10 methyl monoesters, ethyl monoesters, n-propyl monoesters, i-propyl monoesters,
n-butyl monoesters, s-butyl monoesters, t-butyl monoesters. Preferably, the
monoester is a methyl monoester. Preferably the sulfurized fatty acid ester is a
sulfurized fatty acid methyl ester.
As an example of sulfurized fatty acid triesters there may be mentioned
15 sulfurized fatty acid triglycerides which will be fully or partially esterified and will
therefore, in addition to the triesters, optionally comprised diesters and/or
monoesters.
As an example of sulfurized fatty acid polyesters, there may be mentioned
sulfurized pentaerythritol fatty acid esters.
20 An advantage of the invention is to provide a grease composition free from
sulfurized olefins and/or polysulphides. In fact, sulfurized fatty acid esters have a
reduced environmental impact, as these are compounds originating from renewable
resources (fatty substances and fatty acids) and contain a significant proportion of
renewable carbon. This is not the case of the sulfurized olefins which are obtained by
25 sulphurizing olefins, products of hydrocarbon origin and of polysulphides which are
also obtained by sulphurizing hydrocarbon source materials. It is noteworthy to
observe that good extreme-pressure performance was achieved using sulfurized fatty
acid esters rather than sulfurized olefins or polysulphides, which are known for having
better extreme-pressure properties, this being possible in particular due to the
30 additional presence of a dimercaptothiadiazole derivative in the grease composition.
By “active sulphur” is meant within the meaning of the present invention, the
sulphur that a chemical compound is capable of giving up or releasing when this
compound is placed under the conditions of standard ASTM D1662. Standard ASTM
D1662 defines a level of active sulphur of a compound at a given temperature as a
35 difference expressed as a weighted percentage of sulphur content before and after
WO2013087896 6 text for national entry
reacting a sample of this sulfurized compound with a given quantity of copper for a set
time.
The quantity of active sulphur at 150°C (ASTM D1662) in the grease composition
is one of the parameters that are important for obtaining good performance, in
particular under extreme pressure. This quantity of active sulphur at 150°C (5 ASTM
D1662) in the grease composition must not be too low, or it is not possible to achieve
satisfactory extreme-pressure behaviour. It must not be too high, or problems will arise
from corrosiveness of the grease in particular to copper; neither will too high a quantity
of active sulphur at 150°C (ASTM D1662) in the absence of the dimercaptothiadiazole
10 derivative give good performance, in particular under extreme pressure.
Preferably, the quantity of active sulphur at 150°C according to standard ASTM
D1662 provided by the sulfurized fatty acid ester in the grease composition is greater
than or equal to 0.18% by mass with respect to the total mass of grease composition,
preferably greater than or equal to 0.19%, more preferentially greater than or equal to
15 0.20%, even more preferentially greater than or equal to 0.21%.
Preferably, the quantity of active sulphur at 150°C according to standard ASTM
D1662 provided by the sulfurized fatty acid ester in the grease composition is less than
or equal to 5% by mass with respect to the total mass of grease composition,
preferably less than or equal to 4%, more preferentially less than or equal to 2%, even
20 more preferentially less than or equal to 1%.
Preferably, the quantity of sulphur according to standard ASTM D2662 by the
sulfurized fatty acid ester in the grease composition is greater than or equal to 0.35%
by mass with respect to the total mass of grease composition, preferably greater than
or equal to 0.40%, more preferentially greater than or equal to 0.45%.
25 Preferably, the grease composition comprises from 0.5 to 5% by mass with
respect to the total mass of grease composition of sulfurized fatty acid ester, preferably
from 1 to 4%, more preferentially from 2 to 3%.
Preferably, the grease composition according to the invention comprises at
least two different sulfurized fatty acid esters, in order to improve the extreme30
pressure performance, preferentially at least one sulfurized fatty acid methyl ester and
at least one sulfurized fatty acid triglyceride. For a given quantity of active sulphur at
150°C, the combination of two different sulfurized fatty acid esters, in particular a
sulfurized fatty acid methyl ester and a sulfurized fatty acid triglyceride, makes it
possible to improve the extreme-pressure performance because the sulphur is not
35 released in the same manner. The least hindered ester, such as the sulfurized fatty acid
WO2013087896 7 text for national entry
methyl ester, will be the quickest to release the active sulphur, then the most hindered
ester, such as the sulfurized fatty acid triglyceride, will take its turn.
The sulfurized fatty acid esters used in the present invention are products that
are commercially available, for example from the suppliers PCAS, King Industries,
Dover, Magna, Arkema, Rhein Chem5 ie.
Dimercaptothiadiazole derivative
The grease compositions according to the invention comprise at least one
dimercaptiothiadiazole derivative, an essential element of the invention for obtaining
good extreme-pressure performance.
10 Thiadiazoles are heterocyclic compounds comprising two nitrogen atoms, one
sulphur atom, two carbon atoms and two doubles bonds, having the general formula
C2N2SH2, capable of existing in the following forms, respectively: 1,2,3-thiadiazole;
1,2,4-thiadiazole; 1,2,5-thiadiazole; 1,3,4-thiadiazole:
15
20
By dimercaptothiadiazole derivative according to the invention, is meant
25 chemical compounds derived from the following four dimercaptothiadiazole molecules
below: 4,5-dimercapto-1,2,3-thiadiazole, 3,5-dimercapto-1,2,4-thiadiazole,
3,4-dimercapto-1,2,5-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, used alone or in a
mixture:
30
35
N
N
S
N
N
S
N
S
N
N N
S
1, 2, 3 -thiadiazole 1, 2, 4 -thiadiazole
1, 2, 5 -thiadiazole 1, 3, 4 -thiadiazole
WO2013087896 8 text for national entry
5
10
15 In particular, by way of example, 2,5-dimercapto-1,3,4-thiadiazole, derivatives
of 2,5-dimercapto-1,3,4-thiadiazole are molecules of general formula (I) or (II) used
alone or in a mixture:
20
25
30 in which, R1 and R2 are independently of each other, hydrogen atoms, linear or
branched, saturated or unsaturated alkyl groups, comprising from 1 to 24 carbon
atoms, preferably from 2 to 18, more preferentially from 4 to 16, even more
preferentially from 8 to 12 or aromatic substituents, n and m being independently of
each other integers equal to 1, 2, 3 or 4.
NH
HN
S
HN
NH
S
NH
S
HN
HN NH
S
S S S
S
S S
S S
4, 5-dimercapto-1, 2, 3 -thiadiazole 3, 5-dimercapto-1, 2, 4 -thiadiazole
3, 4-dimercapto-1, 2, 5 -thiadiazole 2, 5-dimercapto-1, 3, 4 -thiadiazole
HN NH
S
S S
R1
n
HN NH
S
S S
R1
n
R2
m
(I)
(II)
WO2013087896 9 text for national entry
The dimercaptothiadiazole derivatives are sulfurized compounds such as
sulfurized fatty acid esters, but this sulphur is stabilized in the ring and will not be
released like the sulphur present in the sulfurized fatty acid esters. Thus the
dimercaptothiadiazole derivatives do not contain active sulphur at 150°C unlike
sulfurized fatty acid esters. The active sulphur at 150°C is therefore provided only 5 by
the sulfurized fatty acid ester.
Preferably, the quantity of sulphur according to standard D2622 provided by the
dimercaptothiadiazole derivative in the grease composition is comprised between 0.05
and 0.50% by mass with respect to the total mass of grease composition, preferably
10 between 0.10 and 0.30%, more preferentially between 0.15 and 0.20%.
Preferably, the grease compositions according to the invention comprise from
0.1 to 5% by mass of dimercaptothiadiazole derivative with respect to the total mass of
the lubricant composition, preferably from 0.2 to 4%, more preferentially from
0.3 to 2%, even more preferentially from 0.5 to 1%.
15 The dimercaptothiadiazole derivatives used in the present invention are
products that are commercially available, for example from the suppliers Vanderbilt,
Rhein Chemie, Afton.
Base oil of the polyol ester type
The grease composition according to the invention comprises at least one base
20 oil of renewable origin based on a polyol ester.
The polyol esters that can be used as base oil are diesters, triesters, tetraesters
or complex esters comprising more than four ester functions.
The acids that can be used to form the esters are monocarboxylic acids or
dicarboxylic acids.
25 Preferably, the monocarboxylic acids have from 3 to 22 carbon atoms, more
preferentially from 4 to 20, even more preferentially from 6 to 18, even more
preferentially from 8 to 16, even more preferentially from 10 to 12.
There may be mentioned for example hexanoic acid, octanoic acid,
2-ethylhexanoic acid, isooctanoic acid, nonanoic acid, decanoic acid, isodecanoic acid,
30 oleic acid, stearic acid. Preferably, saturated acids containing no unsaturations are
used.
Preferably, the dicarboxylic acids have from 3 to 22 carbon atoms, more
preferentially from 4 to 20, even more preferentially from 6 to 18, even more
preferentially from 8 to 16, even more preferentially from 10 to 12. There may be
35 mentioned for example succinic acid, adipic acid, azelaic acid, sebacic acid.
WO2013087896 10 text for national entry
The alcohols that can be used to form the esters are monoalcohols (formation
of diesters with dicarboxylic acids), dialcohols, trialcohols or tetraalcohols. The
preferred alcohols are polyols such as neopentylglycol, trimethylolpropane,
pentaerythritol.
In order to obtain a sufficient biodegradability, the grease compositio5 n
according to the invention comprises from 50 to 95% by mass with respect to the total
mass of grease composition of polyol ester, preferably from 60 to 90%, more
preferentially from 70 to 80%.
These base oils of the ester type are chosen for their negligible environmental
10 impact in contrast to the base oils originating from petroleum that are conventionally
used. Nevertheless the utilization of such base oils of polyol ester type has a negative
impact on the extreme-pressure properties, since these base oils of polyol ester type
likewise have a tendency to migrate to the surface of the lubricated parts and are in
competition with the other additives, hence the utilization of the specific combination
15 of dimercaptothiadiazole and sulfurized fatty acid ester.
The base oil of the polyol ester type or the mixture of base oils of the polyol
ester type has a kinematic viscosity at 40°C comprised between 3 and 2000 cSt
(measured according to standard ASTM D445), preferably between 10 and 1500 cSt,
more preferentially between 20 and 1000 cSt, even more preferentially between
20 40 and 500 cSt, even more preferentially between 50 and 200 cSt. These viscosity
ranges, in particular from 50 to 200 cSt, make it possible to achieve a good compromise
between extreme-pressure performance and biodegradability.
The base oils used in the present invention are products that are commercially
available, for example from the suppliers Uniqema, Croda, Oleon, Akzo, Nyco.
25 Soaps
The grease compositions according to the invention are thickened with fatty-acid
metal soaps, which can be prepared separately, or in situ during the manufacture of
the grease (in the latter case, the fatty acid is dissolved in the base oil, then the
appropriate metal hydroxide is added).
30 These thickening agents are products commonly utilized in the field of greases,
easily available and cost-effective. Greases thickened with fatty-acid metal soaps have
a very good mechanical stability, in comparison, for example, with greases comprising
thickening agents based on polyureas, which allows easy use in applications where the
grease is applied in an unconfined space. Furthermore the polyureas are prepared from
35 isocyanate, an extremely toxic compound, it is therefore not desirable to use
WO2013087896 11 text for national entry
thickening agents based on polyureas in order to obtain a grease that is biodegradable,
non toxic and free from products classified under CLP Regulation (EC) No 1272/2008.
The grease according to the invention is therefore free from thickening agents based
on polyurea and therefore comprises only thickening agents of the fatty-acid
metalsoaps typ5 e.
Preferentially, long-chain fatty acids are used, typically comprising from 10 to 28
carbon atoms, saturated or unsaturated, optionally hydroxylated.
The long-chain fatty acids (typically comprising from 10 to 28 carbon atoms), are
for example capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic
10 acid, behenic acid, oleic acid, linoleic acid, erucic acid and their hydroxylated
derivatives. 12-hydroxystearic acid, the best-known derivative of this category, is
preferred. Lithium 12-hydoxystearate is the preferred thickening agent.
These long-chain fatty acids generally originate from vegetable oils, for example
palm oil, castor oil, rapeseed oil, sunflower oil, etc. or animal fats (tallow, whale oil,
15 etc).
Soaps known as simple soaps can be formed by using one or more long-chain
fatty acids. Simple soaps are preferred to the complex soaps, because they are more
easily biodegradable and do not bioaccumulate.
Soaps known as complex soaps can also be formed by using one or more long20
chain fatty acids in combination with one or more carboxylic acids with short
hydrocarbon chains comprising at most 8 carbon atoms.
The saponification agent used to produce the soap can be a metallic compound
of lithium, sodium, calcium, aluminium; preferentially lithium and calcium, and
preferably a hydroxide, oxide or a carbonate of these metals.
25 One or more metallic compounds, whether or not having the same metallic
cation, can be used in the greases according to the invention. It is thus possible to use
lithium soaps in combination with calcium soaps in a smaller proportion.
The metal soaps are utilized at contents of the order of 1 to 20 % by mass with
respect to the total mass of the grease composition, preferably from 2 to 15%,
30 preferentially from 4 to 10%.
Process for preparation of the greases
The greases according to the invention are produced by forming the metal soap
in situ or by using a preformed soap.
WO2013087896 12 text for national entry
The process for the preparation of the grease by forming the metal soap in situ is
the following.
One or more long-chain or short-chain fatty acids are dissolved in a fraction of the
base oil or of the mixture of base oil at a temperature comprised between 80°C and
90°C. This fraction is generally of the order of 40 % to 60% by mass of the total quantit5 y
of oil contained in the final grease.
Then metallic compounds are added at the same temperature, preferentially of
the metallic oxide, hydroxide or carbonate type.
It is thus possible to add a single type of metal or to combine several metals. The
10 preferred metal of the compositions according to the invention is lithium, optionally
combined, in a smaller proportion, with calcium.
The saponification reaction of the long-chain or short-chain fatty acids with the
metallic compound(s) is left to develop at a temperature between 80°C and 90°C.
The water formed is then evaporated off by heating the mixture at a temperature
15 of approximately 100°C to 200°C.
The grease is then cooled down by the remaining fraction of base oil.
Then, at approximately 80°C, the dimercaptothiadazole derivative and the
sulfurized fatty acid ester and any other additives are incorporated.
Stirring is then carried out for a sufficient time in order to obtain a grease
20 composition, which is then ground in order to improve its uniformity.
The process for the preparation of the grease with the preformed metal soap is
identical save that there is no saponification reaction, since the soap is already formed.
These preparation processes are well known to a person skilled in the art.
Consistency of the greases
25 The consistency of a grease measures its hardness or its fluidity at rest. It is
assigned a numerical value by the depth of penetration of a cone of given dimensions
and weight. The grease undergoes prior stirring. The conditions for the measurement
of the consistency of a grease are defined by standard ASTM D 217.
According to their consistency, greases are divided into 9 classes or 9 NLGI
30 (National Lubricating Grease Institute) grades commonly used in the field of greases.
These grades are indicated in the table below.
WO2013087896 13 text for national entry
NLGI grade Consistency according to ASTM D 217 (tenths of a millimetre)
000 445 - 475
00 400 - 430
0 355 - 385
1 310 - 340
2 265 - 295
3 220 - 250
4 175 - 205
5 130 - 160
6 85 - 115
Preferably, the greases according to the invention have a consistency comprised
between 220 and 430 tenths of a millimetre according to standard ASTM D217,
covering grades 00, 0, 1, 2 and 5 3.
Preferably, the greases according to the invention have a consistency comprised
between 265 and 295 tenths of a millimetre according to standard ASTM D217, to
cover grade 2.
Other additives
10 The grease compositions according to the invention can also contain antioxidant
additives, for example antioxidants of the phenolic type, anti-rust additives, such as for
example oxidized waxes or amine phosphates, corrosion inhibitor additives such as
tolyltriazoles.
Technical performance of the greases
15 The grease compositions according to the invention have good extremepressure
performance. In particular, the grease compositions according to the
invention have a welding load measured according to standard ASTM D2596 greater
than 315 kg, preferably greater than or equal to 400 kg. In particular, the grease
compositions according to the invention have a welding load measured according to
20 standard DIN 51350/4 greater than 300 daN, preferably greater than or equal to
320 daN, more preferentially greater than or equal to 340 daN.
The grease compositions according to the invention are also only slightly
corrosive, in particular to metals or metal alloys, and more particularly to copper. In
particular, the grease compositions according to the invention tarnish copper strips
WO2013087896 14 text for national entry
only slightly (classification 1 according to standard ASTM D4048) or tarnish copper
strips only moderately (classification 2 according to standard ASTM D4048).
In addition to having good extreme-pressure properties and not being corrosive
to metals and metal alloys and more particularly to copper, the grease compositions
according to the invention have a reduced environmental impact. In particular, th5 e
greases according to the invention are biodegradable, do not bioaccumulate, are non
toxic for aquatic mediums and are renewable.
Preferably, the grease compositions according to the invention contain
additives which are not hazardous to the environment and human health.
10 Preferably, the grease compositions according to the invention are free from
organic halogenated compounds, nitrite type compounds, metals or metallic
compounds other than sodium, potassium, magnesium, calcium, lithium and/or
aluminium.
Preferably, the grease compositions according to the invention are not toxic to
15 the aquatic environment.
In particular the grease compositions according to the invention have an aquatic
toxicity to algae, daphnia and fish of at least 1000 mg/l according to standards OECD
201, 202 and 203.
Similarly, the main constituents of the grease, i.e. those present at more than
20 5% by mass with respect to the total mass of the grease composition, such as the base
oil and the soap, have an aquatic toxicity to algae and daphnia of at least 100 mg/l
according to standards OECD 201 and 202.
Similarly, when a constituent has an aquatic toxicity to algae and daphnia of at
least 100 mg/l according to standards OECD 201 and 202 (category D), said constituent
25 can be present in the grease at any concentration. The grease compositions according
to the invention have a concentration by mass of constituents having an aquatic
toxicity to algae and daphnia comprised between 10 mg/l and 100 mg/l according to
standards OECD 201 and 202 (category E), less than or equal to 25%. The grease
compositions according to the invention have a concentration by mass of constituents
30 having an aquatic toxicity to algae and daphnia comprised between 1 mg/l and 10 mg/l
according to standards OECD 201 and 202 (category F), less than or equal to 2%,
preferably less than or equal to 1%. This only concerns the constituents of the grease
the concentration by mass in the grease of which is greater than or equal to 0.1%.
The grease compositions according to the invention are biodegradable and do
35 not bioaccumulate. In particular, the grease compositions according to the invention
WO2013087896 15 text for national entry
have a concentration by mass of constituents that are ultimately biodegradable in an
aerobic medium (category A according to standards OECD 301A-F, OECD 306, OECD
301) greater than 75%, a concentration by mass of constituents that are intrinsically
biodegradable in an aerobic medium (category B according to standards OECD 302B,
OECD 302C) or of non-biodegradable constituents and those that do not bioaccumulat5 e
(category C) less than or equal to 25%, and a concentration by mass of nonbiodegradable
constituents and those that bioaccumulate (category X) less than or
equal to 0.1%. This only concerns the constituents of the grease the concentration by
mass in the grease of which is greater than or equal to 0.1%.
10 The grease compositions according to the invention contain at least 45% by
mass with respect to the total mass of grease composition of carbon originating from
renewable raw materials.
The invention also relates to a lubrication process using the above-described
grease compositions, said process consisting of contacting the parts to be lubricated
15 with the above-described grease compositions.
Finally, the invention relates to a lubricant composition comprising at least one
base oil of the polyol ester type, at least one dimercaptothiadiazole and at least one
sulfurized fatty acid ester, the quantity of active sulphur at 150°C according to standard
ASTM D1662 by mass provided by the sulfurized fatty acid ester with respect to the
20 total mass of grease composition being greater than or equal to 0.17%. The polyol ester
type base oil has all the above-mentioned features. The same goes for the
dimercaptothiadiazole derivative and the fatty acid ester. The quantities used are those
described in the present application and are expressed with respect to the total mass
of lubricant composition rather than of grease composition. The lubricant compositions
25 therefore comprise the same additives as the grease compositions except for the soap.
The viscosity of the lubricant compositions is that of the base oils. The lubricant
compositions also have good extreme-pressure and anti-corrosion properties, while
having a reduced environmental impact.
Examples
30 Different grease compositions are prepared from:
- lithium 12-hydroxystearate (thickening agent). Its aquatic toxicity to algae and
daphnia is over 100 mg/l according to standards OECD 201 and 202 (category D). Its
biodegradability is equal to 83.8% according to standard OECD 301B (category A).
- a dimercaptothiadiazole derivative which is a mixture of the products of general
35 formulae (I) and (II), with R1 and R2 being linear alkyl groups comprising an average
WO2013087896 16 text for national entry
number of 12 carbons, n being equal to 1. Its aquatic toxicity to algae and daphnia is
category E according to the standards OECD 201 and 202, its biodegradability is
category C according to standard OECD 301B.
- sulfurized fatty acid methyl ester (sulfurized ester 1), comprising 17% by mass of
sulphur with respect to the total mass of sulfurized ester and 48% by mass of act5 ive
sulphur at 150°C with respect to the total mass of sulfurized ester. Its aquatic toxicity to
algae and daphnia is comprised between 10 mg/l and 100 mg/l according to standards
OECD 201 and 202 (category E). Its biodegradability is category C according to standard
OECD 301B. It comprises 95% by mass of renewable carbon with respect to the total
10 mass of sulfurized ester.
- sulfurized fatty acid triglycerides (sulfurized ester 2), comprising 15% by mass of
sulphur with respect to the total mass of sulfurized ester and 33% by mass of active
sulphur at 150°C with respect to the total mass of sulfurized ester. 60% by mass of the
sulfurized ester with respect to the total mass of sulfurized ester has an aquatic toxicity
15 to algae and daphnia comprised between 10 mg/l and 100 mg/l according to standards
OECD 201 and 202 (category E) and 40% by mass of the sulfurized ester has an aquatic
toxicity to algae and daphnia comprised between 1 mg/l and 10 mg/l according to
standards OECD 201 and 202 (category E). Its biodegradability is category C according
to standard OECD 301B. It comprises 95% by mass of renewable carbon with respect to
20 the total mass of sulfurized ester.
- ester of trimethylolpropane and saturated fatty acids (base oil 1). Its kinematic
viscosity at 100°C (ASTM D445) is 4.4 cSt, its kinematic viscosity at 40°C (ASTM D445) is
19.6 cSt. Its aquatic toxicity to algae and daphnia is over 100 mg/l according to
standards OECD 201 and 202 (category D). Its biodegradability is equal to 79%
25 according to standard OECD 301B (category A). It comprises 81% by mass of renewable
carbon with respect to the total mass of sulfurized ester.
- ester of trimethylolpropane and saturated fatty acids (base oil 2). Its kinematic
viscosity at 100°C (ASTM D445) is 32.2 cSt and its kinematic viscosity at 40°C (ASTM
D445) is 316 cSt. Its aquatic toxicity to algae and daphnia is over 100 mg/l according to
30 standards OECD 201 and 202 (category D). Its biodegradability is equal to 67%
according to standard OECD 301B (category A). It comprises 55% by mass of renewable
carbon with respect to the total mass of sulfurized ester.
- 4,4’-methylene bis 2,6-di-tertio-butylphenol (antioxidant 1),
- Octadecyl 3-(3,5-ditertiobutyl-4-hydroxyphenyl) propanoate (antioxidant 2). Its
35 aquatic toxicity to algae and daphnia is over 100 mg/l according to standards OECD 201
WO2013087896 17 text for national entry
and 202 (category D). Its biodegradability is category B according to standard OECD
301B.
- Oxidized hydrocarbon waxes (corrosion inhibitor 1). Their aquatic toxicity to algae and
daphnia is comprised between 10 mg/l and 100 mg/l according to standards OECD 201
and 202 (category E). Their biodegradability is equal to 55% according to standar5 d
OECD 301B (category B).
- Tolyltriazole (corrosion inhibitor 2). Its aquatic toxicity to algae and daphnia is
comprised between 1 mg/l and 10 mg/l according to standards OECD 201 and 202
(category F). Its biodegradability is equal to 4% according to standard OECD 301B
10 (category C).
in the proportions (% by mass) of the following Table I:
Table I – Composition by mass of the greases
GT1 GT2 GT3 GT4 GI5 GI6 GT7 GT8
Base oil 1 19.63 19.40 19.38 19.49 19.15 19.15 19.25 19.06
Base oil 2 65.72 64.95 64.97 65.26 64.20 64.20 64.60 63.79
Thickening agent 10.96 10.96 10.96 10.96 10.96 10.96 10.96 10.96
Antioxidant 1 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09
Antioxidant 2 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Corrosion inhibitor 1 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Corrosion inhibitor 2 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10
Dimercaptothiadiazole
derivative
0.50 0.50 0.50 0.50 0.50 0.50 - -
Sulfurized ester 1 1.00 - 1.00 2.00 1.00 2.00 1.00 -
Sulfurized ester 2 - 2.00 1.00 - 2.00 1.00 2.00 4.00
The control greases and greases according to the invention have the following
biochemical characteristics (Table II):
15
WO2013087896 18 text for national entry
Table II – Biochemical characteristics of the greases
GT1 GT2 GT3 GT4 GI5 GI6 GT7 GT8
Quantity of sulphur
fatty acid ester
0.17 0.30 0.32 0.34 0.47 0.49 0.47 0.60
Quantity of sulphur
dimercaptothiadiazole
0.15 0.15 0.15 0.15 0.15 0.15 0.00 0.00
Quantity of active
sulphur at 150°C fatty
acid ester
0.082 0.010 0.131 0.163 0.181 0.213 0.181 0.199
Aquatic toxicity
Category E (%)
2.5 2.7 3.1 3.5 3.7 4.1 3.2 3.4
Aquatic toxicity
Category F (%)
0.1 0.9 0.5 0.2 0.9 0.5 0.9 1.7
Biodegradability
Category A (%)
96 95 95 96 94 94 95 94
Biodegradability
Category B + C (%)
3.6 4.6 4.6 4.6 5.6 5.6 5.1 6.1
Renewable carbon (%) 53 53 53 54 54 54 54 54
These grease compositions were subjected to extreme-pressure and corrosiveness
tests (Table III).
The control greases and greases according to the invention have the following
performances (Table III5 ):
WO2013087896 19 text for national entry
Table III - Extreme-pressure and corrosion performance of the greases
GT1 GT2 GT3 GT4 GI5 GI6 GT7 GT8
4-ball extreme pressure
Welding load (kg) (1)
315 315 315 315 400 400 315 315
4-ball extreme pressure
Last load before welding
(daN) (2)
260 260 280 280 300 320 260 280
4-ball extreme pressure
Welding load (daN) (2)
280 280 300 300 320 340 280 300
Copper corrosion (3) 1b 1b 1b 1b 1b 1b 1b 1b
(1) ASTM D2596
(2) DIN 51350/4
(3) ASTM D4048
The grease compositions GT1 to GT4 are control greases comprising both 5 a
dimercaptothadiazole derivative and a sulfurized fatty acid ester but with low active
sulphur contents at 150°C. The grease compositions GT1 to GT4 have a low welding load
of 315 kg (ASTM D2596) or 280 or even 300 daN (DIN 51350/4).
The grease compositions GI5 and GI6 are greases according to the invention
10 comprising both a dimercaptothadiazole derivative and a sulfurized fatty acid ester but
with higher active sulphur contents at 150°C. The grease compositions GI5 and GI6 have
an improved welding load of 400 kg (ASTM D2596) or 320 or even 340 daN (DIN
51350/4).
The grease compositions GT7 and GT8 are control greases not comprising any
15 dimercaptothadiazole derivative, comprising only a sulfurized fatty acid ester with high
active sulphur contents at 150°C. The grease compositions GT5 and GT6 have a low
welding load of 315 kg (ASTM D2596) or 280 or even 300 daN (DIN 51350/4). The
presence of the sulfurized fatty acid ester alone is not sufficient to obtain good
extreme-pressure performance.
20 These grease compositions are in addition only slightly corrosive to copper.
These results demonstrate that obtaining high extreme-pressure performance is
due to the presence of the dimercaptothiadiazole derivative in combination with a
sulfurized fatty acid ester which provides to the grease composition a quantity of active
sulphur at 150°C greater than or equal to 0.18% by mass with respect to the total mass
25 of grease composition. This extreme-pressure performance goes hand in hand with a
WO2013087896 20 text for national entry
low corrosiveness of the grease and a grease which is biodegradable, does not
bioaccumulate, is non-toxic, and originates from renewable raw materials.
WO2013087896 21 text for national entry
WE CLAIM:
1. Grease composition comprising at least one base oil of the polyol ester type, at
least one fatty-acid metal soap, at least one dimercaptothiadiazole derivative and
at least one sulfurized fatty acid ester, the quantity by mass of active sulphur a5 t
150°C according to standard ASTM D1662 provided by the sulfurized fatty acid ester
with respect to the total mass of grease composition being greater than or equal to
0.18%.
10 2. Composition according to claim 1, in which the polyol ester is chosen from
neopentylglycol esters, trimethylolethane esters, trimethylolpropane esters,
pentaerythritol esters and/or dipentaerythritol esters, used alone or in a mixture.
3. Composition according to claim 1 or 2, comprising from 50 to 95% by mass with
15 respect to the total mass of grease composition of a base oil of the polyol ester
type, preferably from 60 to 90%, more preferentially from 70 to 80%.
4. Composition according to claim 1, 2 or 3 in which the dimercaptothiadiazole
derivative is chosen from the derivatives of 4,5-dimercapto-1, 2, 3-thiadiazoles,
20 3,5-dimercapto-1, 2, 4-thiadiazoles, 3,4-dimercapto-1, 2, 5-thiadiazoles,
2,5-dimercapto-1, 3, 4-thiadiazoles, used alone or in a mixture.
5. Composition according to any one of claims 1 to 4, comprising from 0.1 to 5% by
mass of dimercaptothiadiazole derivative with respect to the total mass of grease
25 composition, preferably from 0.2 to 2%, more preferentially from 0.5 to 1%.
6. Composition according to any one of claims 1 to 5, in which the sulfurized fatty acid
ester is a fatty acid triglyceride and/or a fatty acid methyl ester, used alone or in a
mixture.
30
7. Composition according to any one of claims 1 to 6, comprising from 0.5 to 5% by
mass of sulfurized fatty acid ester with respect to the total mass of grease
composition, preferably from 1 to 4%, more preferentially from 2 to 3%.
WO2013087896 22 text for national entry
8. Composition according to any one of claims 1 to 7, in which the fatty-acid metal
soap is a simple fatty-acid metal soap, preferably of lithium or calcium.
9. Composition according to any one of claims 1 to 8, in which the fatty-acid metal
soap is lithium 12-hydroxystearate5 .
10. Composition according to any one of claims 1 to 9, comprising from 1 to 20 % by
mass with respect to the total mass of the grease composition of fatty-acid metal
soap, preferably from 2 to 15%, preferentially from 4 to 12%.
10
11. Composition according to any one of claims 1 to 10, in which the polyol ester, or
the mixture of polyol esters, has a kinematic viscosity at 40°C, measured according
to standard ASTM D 445, comprised between 3 and 2000 cSt, preferably between
10 and 1500 cSt, more preferentially between 40 and 500 cSt, even more
15 preferentially between 50 and 200 cSt.
12. Composition according to any one of claims 1 to 11, having a consistency according
to standard ASTM D217 comprised between 220 and 430 tenths of a millimetre,
preferably between 265 and 295 tenths of a millimetre.
20
13. Composition according to any one of claims 1 to 12, comprising a quantity by mass
of active sulphur at 150°C according to standard ASTM D1662 provided by the
sulfurized fatty acid ester with respect to the total mass of grease composition,
greater than or equal to 0.19% by mass, preferentially greater than or equal to
25 0.20%, even more preferentially greater than or equal to 0.21%.
14. Composition according to any one of claims 1 to 13, having a welding load
according to standard ASTM D2596 greater than 315 kg, preferably greater than or
equal to 400 kg.
30
15. Composition according to any one of claims 1 to 14, having a welding load
according to standard DIN 51350/4 greater than 300 daN, preferably greater than
or equal to 320 daN, more preferentially greater than or equal to 340 daN, even
more preferentially greater than or equal to 360 daN.
35
WO2013087896 23 text for national entry
16. Composition according to any one of claims 1 to 15, having a classification of
corrosiveness to copper according to standard ASTM D4048 of 1 or 2.
17. Use in a grease composition comprising at least one base oil of the polyol ester type
and at least one fatty-acid metal soap, at least one dimercaptothiadiazo5 le
derivative and at least one sulfurized fatty acid ester, the quantity by mass of active
sulphur at 150°C according to standard ASTM D1662 provided by the sulfurized
fatty acid ester being greater than or equal to 0.18% with respect to the total mass
of grease composition, in order to improve the extreme-pressure performance
10 according to standards ASTM D2596 and/or DIN 51350/4 of the grease
composition.
18. Lubricant composition comprising at least one base oil of the polyol ester type, at
least one dimercaptothiadiazole derivative and at least one sulfurized fatty acid
15 ester, the quantity by mass of active sulphur at 150°C according to standard ASTM
D1662 provided by the sulfurized fatty acid ester with respect to the total mass of
lubricant composition being greater than or equal to 0.18%.