EP2791297A1

EP2791297A1 - Fatty composition

Info

Publication number: EP2791297A1
Application number: EP12801608.6A
Authority: EP
Inventors: Nicole Genet; Xavier BARC
Original assignee: Total Raffinage Marketing SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2011-12-16
Filing date: 2012-12-14
Publication date: 2014-10-22
Anticipated expiration: 2032-12-14
Also published as: FR2984349B1; KR20140107459A; AR089275A1; BR112014014506A2; WO2013087891A1; CN104024388A; JP2015504933A; EP2791297B1; MX2014007283A; US20140329731A1; BR112014014506B1; FR2984349A1; JP6114304B2; CA2858930A1

Abstract

The invention relates to a fatty composition including at least one basic polyol ester oil, at least one fatty-acid metal soap, at least one fluorinated polymer, and at least one sulfurous fatty acid ester, wherein the amount of active sulfur provided by the sulfurous fatty acid ester relative to the total fatty composition at 150°C according to the ASTM D1662 standard is greater than or equal to 0.15 wt %.

Description

FAT COMPOSITION

Field of the invention

The present invention relates to grease compositions, in particular to grease compositions having a reduced impact on the environment and having good extreme-pressure and corrosion properties, in particular with respect to metals or alloys. metal.

Technological background of the invention

The recent period has seen the rise of global environmental problems and the imposition of the protection of the terrestrial biosphere as a major issue in all sectors of the industry. The field of greases is no exception, and the risk of water and soil pollution, such as the natural rejection of base oils, the main ingredients of these products, justifies the expectation today of the latter progress in the field including biodegradability for uses that involve risks of external leakage of fats. At the same time, the machines, always more powerful, are solicited under more and more severe conditions and require from their lubricating products, in addition for example of biodegradability, significant performance gains in terms of properties Extreme pressure and corrosion.

US 6,316,392 discloses a grease composition having improved corrosion resistance and comprising at least one base oil, a fatty acid metal soap and an extreme pressure additive which may be selected from a sulfur fatty acid ester or PTFE. However, the compositions described herein do not include the specific combination of a fluorinated polymer and a sulfur fatty acid ester. In addition, this document gives no indication as to the amount of active sulfur provided by the sulfur fatty acid ester.

The subject of the present invention is a grease composition that can be used in devices that have risks of external leakage of grease, such as automobiles, construction machinery or agricultural equipment, and which has both a reduced impact on the environment, good performance in extreme pressure and low corrosion against metals or metal alloys.

Surprisingly, the Applicant has found that a fat composition having a specific combination of a fatty acid ester sulfur, said ester providing a certain amount of active sulfur at 150 ° C according to ASTM standard D1662, and a fluoropolymer, in a base oil of the polyol ester type, has very good extreme-pressure properties, is not particularly corrosive with respect to metals or metal alloys, in particular vis-à-vis copper screws, while having a reduced impact on the environment.

Brief description of the invention

The invention relates to a grease composition comprising at least one polyol ester base oil, at least one fatty acid metal soap, at least one fluorinated polymer and at least one sulfur fatty acid ester, the amount of active sulfur at 150 ° C according to ASTM D1662 in mass provided by the fatty acid ester sulfur, relative to the total mass of fat composition, being greater than or equal to 0.15%.

Preferably, the polyol ester is chosen from neopentyl glycol esters, trimethylolethane esters, trimethylolpropane esters, pentaerythritol esters and / or dipentaerythritol esters, taken alone or as a mixture.

Preferably, the composition comprises from 50 to 95% by weight, based on the total weight of the fat composition, of a polyol ester base oil, preferably from 60 to 90%, more preferably from 70 to 90% by weight. 80%.

Preferably, the fluoropolymer is polytetrafluoroethylene.

Preferably, the composition comprises from 1 to 10% by weight of fluoropolymer, relative to the total mass of fat composition, preferably from 2 to 8%, more preferably from 3 to 5%.

Preferably, the sulfur fatty acid ester is a fatty acid triglyceride and / or a fatty acid methyl ester, taken alone or as a mixture.

Preferably, the composition comprises from 0.5 to 5% by weight of sulfur fatty acid ester, relative to the total mass of fat composition, preferably from 1 to 4%, more preferably from 2 to 3%. .

Preferably, the fatty acid metal soap is a simple metal soap of fatty acid, preferably lithium or calcium.

Preferably, the fatty acid metal soap is lithium 12-hydroxystearate.

Preferably, the composition comprises from 1 to 20% by weight, relative to the total weight of the fat composition, of fatty acid metal soap, preferably from 2 to 15%, preferably from 4 to 12%.

Preferably, the polyol ester, or the mixture of polyol esters, has a kinematic viscosity at 40 ° C, measured according to ASTM D 445, between 3 and 2000 cSt, preferably between 10 and 1500 cSt, more preferably between 40 and 500 cSt, still more preferably between 50 and 200 cSt.

Preferably, the composition has a consistency according to ASTM D217 of between 220 and 430 tenths of millimeters, preferably between 265 and 295 tenths of millimeters.

Preferably, the amount of active sulfur at 150 ° C. according to ASTM D1662 in mass provided by the sulfur fatty acid ester, relative to the total mass of fat composition, is greater than or equal to 0.15%. by weight, preferably greater than or equal to 0.18%, more preferably greater than or equal to 0.20%.

Preferably, the composition has a weld load according to the ASTM standard

D2596 greater than 315 kg, preferably greater than or equal to 400 kg.

Preferably, the composition has a welding load according to DIN 51350/4 greater than 300 daN, preferably greater than or equal to 320 daN, more preferably greater than or equal to 340 daN, even more preferably greater than or equal to 360 daN .

Preferably, the composition has a copper corrosion rating according to ASTM D4048 of 1 or 2.

The invention also relates to use in a grease composition comprising at least one polyol ester base oil and at least one fatty acid metal soap, at least one fluorinated polymer and at least one ester of sulfur-containing fatty acid, the amount of active sulfur at 150 ° C. according to the ASTM D1662 standard by weight provided by the sulfur-containing fatty acid ester being greater than or equal to 0.15%, relative to the total mass of composition of grease, to improve the extreme pressure performance according to ASTM D2596 and / or DIN 51350/4 of the grease composition.

detailed description

Ester of sulfur fatty acid

The fat according to the invention comprises at least one sulfur-containing fatty acid ester.

The sulfur-containing fatty acid esters are obtained by sulfurizing fatty acid esters. Said fatty acid esters are obtained by reaction between one or more fatty acids and alcohols of all kinds or by transesterification between one or more esters of fatty acids and alcohols of all kinds. By sulfur fatty acid ester is meant an ester of at least one sulfur-containing fatty acid, it being understood that it is mostly an ester of a mixture of sulfur-containing fatty acids. The fatty acids that can be used to form the sulfur-containing fatty acid esters are all fatty acids comprising from 6 to 24 carbon atoms, preferably from 14 to 22 carbon atoms, more preferably from 16 to 20 carbon atoms. The fatty acids comprising 18 carbon atoms are the majority fatty acids, that is to say that they are present in a mass concentration of at least 50% relative to the total weight of sulfur fatty acid ester. .

The sulfur-containing fatty acid esters may be sulfur-containing fatty acid monoesters, sulfur-containing fatty acid diesters, sulfur-containing fatty acid triesters or sulfur-containing fatty acid polyesters, taken alone or as a mixture.

Preferred sulfur-containing fatty acid monoesters are alkyl monoesters of

CC _4, such as methyl monoesters, ethyl monoesters, monoesters of / i-propyl, monoesters / ^'-propyl, monoesters of / i-butyl, monoesters of s-butyl, monoesters f-butyl. Preferably, the monoester is a methyl monoester. Preferably, the sulfur fatty acid ester is a fatty acid methyl ester of sulfur.

As examples of sulfur fatty acid triesters, mention may be made of sulfur-containing fatty acid triglycerides which will be completely or partially esterified and will therefore optionally comprise, in addition to triesters, diesters and / or monoesters.

As an example of sulfur fatty acid polyesters, mention may be made of sulfurized fatty acid pentaerythritol esters.

An advantage of the invention is to provide a grease composition free of sulfur-containing olefins and / or polysulfides. In fact, sulfur-containing fatty acid esters have a reduced impact on the environment since they are compounds derived from renewable resources (fats and fatty acids) that contain a significant renewable carbon content. This is not the case of sulfurized olefins which are obtained by sulphurization of olefins, products of hydrocarbon origin and polysulfides which are also obtained by sulphurization of hydrocarbon feedstocks. It is remarkable to note that good extreme-pressure performance has been obtained by using sulfur-containing fatty acid esters rather than sulfur-containing olefins or polysulfides, which are known to have better extreme-pressure properties, this being notably possible thanks to the presence in addition to a fluoropolymer in the fat composition.

The term "active sulfur" in the sense of the present invention, the sulfur that a chemical compound is able to yield or release when placing this compound in the conditions of ASTM D1662. ASTM D-1662 defines an active sulfur content of a compound at a given temperature as a difference expressed as a weight percent of sulfur content before and after reaction of a sample of that sulfur compound with a given amount of copper for a period of time. a fixed time.

The amount of active sulfur at 150 ° C. (ASTM standard D1662) in the grease composition is one of the important parameters for obtaining good performance, especially at extreme pressure. This amount of active sulfur at 150 ° C (ASTM D1662) in the grease composition should not be too low, otherwise satisfactory extreme pressure behavior can not be obtained. It should not be too high, otherwise it is the corrosion of the grease, particularly vis-à-vis metals and metal alloys, especially vis-à-vis copper, which is a problem and also a quantity of active sulfur at 150 ° C (ASTM D1662) too high without the presence of the fluoropolymer will also give good performance especially in extreme pressure.

Preferably, the amount of active sulfur at 150 ° C. according to ASTM D 1662 provided by the sulfur fatty acid ester in the grease composition is greater than or equal to 0.15% by weight, relative to the mass. total fat composition, preferably greater than or equal to 0.18%, more preferably greater than or equal to 0.20%.

Preferably, the amount of active sulfur at 150 ° C. according to the ASTM D 1662 standard provided by the sulfur fatty acid ester in the grease composition is less than or equal to 5% by weight, relative to the total weight of grease composition, preferably less than or equal to 4%, more preferably less than or equal to 2%, even more preferably less than or equal to 1%.

Preferably, the amount of sulfur according to ASTM D2622 provided by the sulfur fatty acid ester in the fat composition is greater than 0.3% by weight, based on the total mass of fat composition, preferably greater than or equal to 0.34%.

Preferably, the grease composition comprises from 0.5 to 5% by weight, based on the total weight of fat composition, of sulfur-containing fatty acid ester, preferably from 1 to 4%, more preferably from 2 to at 3%.

Preferably, the grease composition according to the invention comprises at least two different sulfur-containing fatty acid esters, for improving the extreme-pressure performance, preferably at least one fatty-acid methyl ester and at least one acid triglyceride. sulfurous fat. At a given amount of active sulfur at 150 ° C, the combination of two different sulfur-containing fatty acid esters, in particular a methyl ester of sulfur fatty acid and a fatty acid triglyceride sulfur, improves the extreme-pressure performance because the sulfur is not released in the same way. The less clogged ester, such as the sulfurized fatty acid methyl ester, will release the active sulfur faster, then the more congested ester, such as sulfur fatty acid triglyceride will take over.

The sulfur-containing fatty acid esters used in the present invention are commercially available products, for example from PCAS, King Industries, Dover, Magna, Arkema and Rhein Chemie suppliers.

Fluoropolymer

The grease compositions according to the invention comprise at least one fluoropolymer or fluoropolymer, an essential element of the invention to obtain good extreme-pressure performance.

The fluoropolymers are chosen from polytetrafluoroethylenes or PTFE, poly (tetrafluoroethylene / hexafluoropropene) or FEP, poly (tetrafluoroethylene / perfluorinated ether / vinyl ether) or PFA, perfluorinated polyethers, poly (chlorotrifluoroethylene) or PCTFE, polyvinylidene fluoride or PVDF, poly (ethylene / tetrafluoroethylene) or ETFE, poly (ethylene / chlorotrifluoroethylene) or ECTFE, polyvinyl fluoride or PVF, polyvinylidene fluoride / hexafluoropropene, polytetrafluoroethylene / perfluorinated vinyl ether ), poly (tetrafluoroethylene / proprene), fluorosilicones, polyfluorophosphazenes.

Preferably the fluoropolymer consists exclusively of carbon atoms and fluorine atoms.

Preferably the fluoropolymer is a polytetrafluoroethylene.

Preferably, the polytetrafluoroethylene has a mean particle size of between 0.1 and 100 μιη, preferably between 0.2 and 50, more preferably between 0.2 and 10, still more preferably between 0.2 and 5, and even more preferably between 0.2 and 1, still more preferably between 0.2 and 0.5.

The grease composition according to the invention comprises from 1 to 10% by weight of fluoropolymer, relative to the total mass of fat composition, preferably from 2 to 8%, more preferably from 3 to 5%. A smaller amount of fluoropolymer will not achieve good extreme pressure performance, a larger amount will have a negative impact on the environment. The fluoropolymers used in the present invention are commercially available products, for example from suppliers Dupont, Solvay, Maflon, Xeon, Shamrock.

Polyol ester base oil

The grease composition according to the invention comprises at least one base oil of renewable origin based on a polyol ester.

The polyol esters which can be used as base oils 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.

Preferably, the monocarboxylic acids have from 3 to 22 carbon atoms, more preferably from 4 to 20, still more preferably from 6 to 18, still more preferably from 8 to 16, even more preferably from 10 to 12.

For example, hexanoic, octanoic, 2-ethylhexanoic, isooctanoic, nonanoic, decanoic, isodecanoic, oleic and stearic acids may be mentioned. Saturated acids that do not contain unsaturations are preferably used.

Preferably, the dicarboxylic acids have from 3 to 22 carbon atoms, more preferably from 4 to 20, even more preferably from 6 to 18, still more preferably from 8 to 16, even more preferably from 10 to 12. It is possible to mention examples are succinic, adipic, azelaic and sebacic acids.

The alcohols which can be used to form the esters are monoalcohols (formation of diesters with dicarboxylic acids), dihydric alcohols, trihydric alcohols or tetrahydric alcohols. Preferred alcohols are polyols such as neopentyl glycol, trimethylolpropane, pentaerythritol.

To obtain sufficient biodegradability, the grease composition according to the invention comprises from 50 to 95% by weight, relative to the total weight of the fat composition, of the polyol ester, preferably from 60 to 90%, more preferably from 70 to 80%.

These ester base oils are chosen for their negligible impact on the environment, unlike the petroleum-based base oils conventionally used. However, the use of such polyol ester base oils has a negative impact on the extreme-pressure properties, since these polyol ester base oils tend to also go to the surface of the lubricated parts and are competition with other additives, hence the use of the specific combination of fluoropolymer and fatty acid ester sulfur.

The polyol ester base oil or the polyol ester base oil mixture has a kinematic viscosity at 40 ° C of between 3 and 2000 cSt (ASTM D445), preferably between 10 and 1500 cSt, more preferably between 20 and 1000 cSt, more preferably between 40 and 500 cSt, even more preferably between 50 and 200 cSt. These viscosity ranges, in particular from 50 to 200 cSt, make it possible to obtain a good compromise between extreme pressure performance and biodegradability.

The base oils used in the present invention are commercially available products, for example from Uniqema, Croda, Oléon, Akzo, Nyco suppliers.

Soaps

The grease compositions according to the invention are thickened with fatty acid metal soaps, which may be prepared separately, or in situ during the manufacture of the grease (in the latter case, the fatty acid is dissolved in the grease). base oil, then add the appropriate metal hydroxide).

These thickeners are commonly used products in the field of fats, readily available and inexpensive. Greases thickened with fatty acid metal soaps have a very good mechanical stability, compared, for example, with greases comprising polyurea thickeners, which allows easy use in applications where the grease is in a chamber unconfined. In addition, the polyureas are prepared from isocyanate, an extremely toxic compound. It is therefore not desirable to use thickeners based on polyureas to obtain a biodegradable fat, non-toxic and free of products classified according to the CLP Regulation (EC No 1272/2008). The grease according to the invention is therefore free of thickeners based on polyurea and therefore comprises only metal fatty acid type thickeners.

Preferred is long-chain fatty acids, 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, lauric, myristic, palmitic, stearic, arachidic, behenic, oleic, linoleic and erucic acids, and their derivatives. hydroxylated. Hydroxystearic acid 12 is the most well-known derivative of this category and is preferred. Lithium 12-hydoxystearate is the preferred thickener.

These long-chain fatty acids generally come from vegetable oils, for example palm oil, castor oil, rapeseed oil, sunflower oil, ... or animal fats (tallow, whale oil, etc.).

So-called simple soaps can be formed using one or more long-chain fatty acids. Simple soaps are preferred over complex soaps because they are more easily biodegradable and non-bioaccumulative.

So-called complex soaps can also be formed by using one or more long-chain fatty acids in combination with one or more short-chain hydrocarbon carboxylic acids comprising at most 8 carbon atoms.

The saponification agent used to make the soap may be a metal compound of lithium, sodium, calcium, aluminum, preferably lithium and calcium, and preferably a hydroxide, oxide or carbonate of these metals.

One or more metal compounds, with or without the same metal cation, may be used in the greases according to the invention. It is thus possible to associate lithium soaps, combined with calcium soaps to a lesser extent.

The metal soaps are used at levels of the order of 1 to 20% by weight, relative to the total mass of the grease composition, preferably from 2 to 15%, preferably from 4 to 12%.

Fat preparation process

The greases according to the invention are manufactured by forming the metal soap in situ or by using a preformed soap.

The method of preparing the fat by forming the metal soap in situ is as follows.

One or more long chain or short chain fatty acids are dissolved in a fraction of the base oil or base oil mixture at a temperature between 80 ° C and 90 ° C. This fraction is generally of the order of 40% to 60% by weight of the total amount of oil contained in the final fat.

Metallic compounds, preferably of oxide, hydroxide or metal carbonate type, are then added at the same temperature.

One type of metal can be added together or several metals can be combined. The preferred metal of the compositions according to the invention is lithium, possibly combined, to a lesser extent, with calcium. The saponification reaction of the long chain or short chain fatty acids is allowed to proceed with the metal compound (s) at a temperature between 80 ° C and 90 ° C.

The formed water is then evaporated by baking the mixture at a temperature of about 100 ° C to 200 ° C.

The grease is then cooled by the remaining fraction of base oil.

The fluorinated polymer and the sulfur fatty acid ester and any other additives are then incorporated at about 80 ° C.

It is then kneaded for a time sufficient to obtain a fat composition, which is then milled to make it more homogeneous.

The method of preparing the fat with the preformed metal soap is identical, except that there is no saponification reaction since the soap is already formed. These preparation methods are well known to those skilled in the art.

The consistency of a grease measures its hardness or fluidity at rest. It is quantified by the depth of penetration of a cone of given dimensions and mass. The fat is previously subjected to mixing. The conditions for measuring the consistency of a grease are defined by ASTM D 217.

Consistency of fats

Depending on their consistency, the fats are divided into 9 classes or 9 NLGI grades (National Lubricating Grease Institute) commonly used in the field of fats. These grades are shown in the table below.

Preferably, the greases according to the invention have a consistency of between 220 and 430 tenths of a millimeter according to the ASTM D217 standard, to cover the grades 00, 0, 1, 2 and 3. Preferably, the greases according to the invention have a consistency of between 265 and 295 tenths of a millimeter according to the ASTM D217 standard, to cover the grade 2.

Other additives

The grease compositions according to the invention may also contain antioxidant additives, for example phenolic antioxidants, anti-rust additives, for example oxidized waxes or amine phosphates, anti-oxidant additives, such as tolyltriazoles or dimercaptothiadiazole derivatives.

Technical performance of greases

The grease compositions according to the invention have good extreme-pressure performance. In particular, the grease compositions according to the invention have a weld load measured according to 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 weld load measured according to DIN 51350/4 greater than 300 daN, preferably greater than or equal to 320 daN, more preferably greater than or equal to 340 daN, even more preferably greater than or equal to 360 daN.

The grease compositions according to the invention are also very slightly corrosive, in particular with respect to metals and metal alloys, and more particularly with respect to copper. In particular, the grease compositions according to the invention only slightly tarnish the copper blades (classification 1 according to ASTM D4048) or only slightly tarnish the copper blades (classification 2 according to ASTM D4048).

The grease compositions according to the invention in addition to having good extreme-pressure properties and not being corrosive with respect to metals and metal alloys, and more particularly with respect to copper, have a reduced impact. on the environment. In particular, the greases according to the invention are biodegradable, non-bioaccumulative, non-toxic for aquatic environments and are renewable.

Preferably, the grease compositions according to the invention contain additives which do not present a danger for the environment and human health.

Preferably, the grease compositions according to the invention are free of halogenated organic compounds, nitrite compounds, metals or metal compounds other than sodium, potassium, magnesium, calcium, lithium and / or 'aluminum. Preferably, the grease compositions according to the invention are not toxic to the aquatic environment.

In particular, the grease compositions according to the invention have an aquatic toxicity of at least 1000 mg / l on algae, daphnids and fish according to the OECD 201, 202 and 203 standards.

Likewise, the main constituents of the fat, that is to say those present at more than 5% by weight, relative to the total mass of the fat composition, such as the base oil, and the soap have an aquatic toxicity of at least 100 mg / l on algae and daphnids according to OECD 201 and 202.

Similarly, when a constituent has an aquatic toxicity of at least 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D), that constituent may be present in fat at any concentration. The fat compositions according to the invention have a mass concentration of constituents having an aquatic toxicity of between 10 mg / l and 100 mg / l on algae and daphnids according to OECD 201 and 202 (category E), less than or equal to at 25%. The fat compositions according to the invention have a mass concentration of constituents having an aquatic toxicity of between 1 mg / l and 10 mg / l on algae and daphnids according to OECD 201 and 202 (category F), less than or equal to at 2%, preferably less than or equal to 1%. This only concerns the constituents of the fat whose mass concentration in the fat is greater than or equal to 0.1%.

The grease compositions according to the invention are biodegradable and non-bioaccumulative. In particular, the grease compositions according to the invention have a mass concentration of constituents which are ultimately biodegradable in an aerobic medium (category A according to OECD 301A-F, OECD 306, OECD 301) of greater than 75%, a mass concentration of constituents intrinsically biodegradable in an aerobic environment (category B according to OECD 302B, OECD 302C) or non-biodegradable and non-bioaccumulative constituents (category C) up to 25%, and a mass concentration of non-biodegradable and accumulatable constituents (category X ) less than or equal to 0.1%. This only concerns the constituents of the fat whose mass concentration in the fat is greater than or equal to 0.1%.

The grease compositions according to the invention contain at least 45% by weight, based on the total mass of grease composition, of carbon originating from renewable raw materials. The invention also relates to a method of lubrication using the fat compositions described above. The method of contacting the parts to be lubricated with the grease compositions described above.

Examples

Various fat compositions are prepared from:

- lithium 12-hydroxystearate (thickener). Its aquatic toxicity is greater than 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D). Its biodegradability is 83.8% according to OECD 301B (category A).

- polytetrafluoroethylene (PTFE). Its aquatic toxicity is greater than 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D). Its biodegradability is category C according to OECD 301B.

- fatty acid methyl ester sulfur (sulfur ester 1), comprising 17% by weight, relative to the total weight of sulfur ester, sulfur and 48% by mass of active sulfur at 150 ° C relative to the mass total of sulfur ester. Its aquatic toxicity is between 10 mg / l and 100 mg / l on algae and daphnids according to OECD 201 and 202 (category E). Its biodegradability is category C according to OECD 301B. It comprises 95% by weight of renewable carbon, based on the total weight of sulfur ester.

triglycerides of sulfur-containing fatty acid (sulfur ester 2), comprising 15% by weight, relative to the total weight of sulfur-containing ester, sulfur and 33% by mass of active sulfur at

150 ° C relative to the total mass of sulfur ester. 60% by weight of the sulfur ester, with respect to the total weight of sulfur ester, has an aquatic toxicity of between 10 mg / l and 100 mg / l on algae and daphnids according to OECD 201 and 202 ( category E) and 40% by weight of the sulfur ester has an aquatic toxicity of between 1 mg / l and 10 mg / l on algae and daphnids according to OECD 201 and 202 (category E). Its biodegradability is category C according to OECD 301B. It comprises 95% by weight of renewable carbon, based on the total weight of sulfur ester.

- trimethylolpropane ester 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 is greater than 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D). Its biodegradability is 79% according to OECD 301B (Category A). It comprises 81% by weight of renewable carbon, based on the total weight of sulfur ester. - trimethylolpropane ester 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 is greater than 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D). Its biodegradability is 67% according to OECD 301B (Category A). It comprises 55% by mass of renewable carbon, relative to the total mass of sulfur ester.

4,4'-methylenebis 2,6-di-tert-butylphenol (antioxidant 1),

Octadecyl 3- (3,5-ditertiobutyl-4-hydroxyphenyl) propanoate (antioxidant 2). Its aquatic toxicity is greater than 100 mg / l on algae and daphnids according to OECD 201 and 202 (category D). Its biodegradability is class B according to OECD 301B.

- Oxidized hydrocarbon waxes (anti-corrosion 1). Its aquatic toxicity is between 10 mg / l and 100 mg / l on algae and daphnids according to OECD 201 and 202 (category E). Its biodegradability is 55% according to the OECD 301B standard (category B).

- Tolyltriazole (anti-corrosion 2). Its aquatic toxicity is between 1 mg / l and 10 mg / l on algae and daphnids according to OECD 201 and 202 (category F). Its biodegradability is 4% according to OECD 301B (category C).

in the proportions (% by weight) of Table I below:

Table I - Mass composition of fats

The control fats and according to the invention have the following biochemical characteristics (Table II): Table II - Biochemical characteristics of fats

These grease compositions are subjected to extreme pressure and corrosion tests (Table III).

Table III - Extreme Pressure Performance and Grease Corrosion

ASTM D2596

DIN 51350/4

ASTM D4048

It is found that the control grease composition 1 has a very poor weld load of 160 kg (ASTM D2596) or 160 daN (DIN 51350/4). The presence of PTFE in the grease composition is not sufficient to ensure good extreme-pressure properties.

It is found that control grease composition 5 has a low weld load of 315 kg (ASTM D2596) or 300 daN (DIN 51350/4). The presence of sulfur fatty acid ester alone in the fat composition is not sufficient to ensure good extreme-pressure properties. When 2% sulfur ester 2 is added, the weld load is somewhat improved, since it is 315 kg (ASTM D2596) or 300 daN (DIN 51350/4) in the control grease composition 3, but still insufficient because the amount of active sulfur at 150 ° C is too low.

The presence of 4% sulfur ester 2 and PTFE in the grease composition according to the invention 2 makes it possible to achieve a welding load of 400 kg (ASTM D2596) or 360 daN (DIN 51350/4).

The combination of 2% sulfur ester 1 and PTFE in the grease composition according to the invention 4 also makes it possible to achieve a welding load of 400 kg (ASTM D2596) or 340 daN (DIN 51350/4).

The results of the control fat 6 show that the combination of a fatty acid ester sulfur with PTFE is not alone sufficient to ensure good extreme pressure properties, when the amount of active sulfur at 150 ° C according to the standard ASTM D1662 provided by the sulfur fatty acid ester is less than 0.15%.

The grease according to the invention 7 shows that a combination of a sulfur-containing fatty acid ester and PTFE in a grease composition, the amount of active sulfur at 150 ° C. according to ASTM D1662 standard provided by the ester of sulfur-containing fatty acid being greater than or equal to 0.15%, makes it possible to improve the extreme pressure properties.

In addition, the grease compositions according to the invention are very slightly corrosive to copper.

These results demonstrate that obtaining high extreme pressure performance is due to the presence of the fluorinated polymer in combination with a sulfur fatty acid ester which provides in the fat composition an amount of active sulfur at 150 ° C greater than or equal to at 0.15% by weight, based on the total mass of fat composition. This extreme-pressure performance goes hand in hand with low corrosion of grease and a fat that is biodegradable, non-accumulative, non-toxic, and derived from renewable raw materials.

Claims

A grease composition comprising at least one polyol ester base oil, at least one fatty acid metal soap, at least one fluorinated polymer and at least one sulfur fatty acid ester, the amount of active sulfur at 150 ° C according to ASTM D1662 in mass provided by the sulfur fatty acid ester, relative to the total mass of fat composition, being greater than or equal to 0.15%.

2. Composition according to claim 1, in which the polyol ester is chosen from neopentyl glycol esters, trimethylolethane esters, trimethylolpropane esters, pentaerythritol esters and / or dipentaerythritol esters, taken alone or as a mixture.

A composition according to claim 1 or 2 comprising from 50 to 95% by weight, based on the total weight of the fat composition, of a polyol ester base oil, preferably from 60 to 90%, more preferably from 70 to 80%.

The composition of claim 1, 2 or 3 wherein the fluoropolymer is polytetrafluoroethylene.

5. Composition according to any one of claims 1 to 4 comprising 1 to 10% by weight of fluoropolymer, relative to the total mass of fat composition, preferably from 2 to 8%, more preferably from 3 to 5% by weight. %.

6. A composition according to any of claims 1 to 5 wherein the sulfur fatty acid ester is a fatty acid triglyceride and / or a fatty acid methyl ester, taken alone or in admixture.

7. Composition according to any one of claims 1 to 6 comprising from 0.5 to 5% by weight of fatty acid ester sulfur, relative to the total mass of fat composition, preferably from 1 to 4% more preferably from 2 to 3%.

8. Composition according to any one of claims 1 to 7 wherein the metal soap of fatty acid is a simple metal soap of fatty acid, preferably lithium or calcium.

9. Composition according to any one of claims 1 to 8 wherein the metal soap of fatty acid is lithium 12-hydroxystearate.

10. Composition according to any one of claims 1 to 9 comprising from 1 to 20% by weight, based on the total weight of the fat composition, of fatty acid metal soap, preferably from 2 to 15%, preferably from 4 to 12%.

11. A composition according to any one of claims 1 to 10 wherein the polyol ester, or the mixture of polyol esters, has a kinematic viscosity at 40 ° C, measured according to ASTM D 445, between 3 and 2000 cSt, preferably between 10 and 1500 cSt, more preferably between 40 and 500 cSt, still more preferably between 50 and 200 cSt.

12. Composition according to any one of claims 1 to 11 having a consistency according to ASTM D217 between 220 and 430 tenths of millimeters, preferably between 265 and 295 tenths of millimeters.

13. Composition according to any one of claims 1 to 12 comprising a quantity of active sulfur at 150 ° C according to ASTM D1662 by mass provided by the fatty acid ester sulfur, relative to the total weight of the composition of grease, greater than or equal to 0.18% by weight, preferably greater than or equal to 0.20%.

14. Composition according to any one of claims 1 to 13 having a weld load according to ASTM D2596 greater than 315 kg, preferably greater than or equal to 400 kg.

15. Composition according to any one of claims 1 to 14 having a welding load according to DIN 51350/4 greater than 300 daN, preferably greater than or equal to 320 daN, more preferably greater than or equal to 340 daN, even more preferably greater than or equal to 360 daN.

16. A composition according to any one of claims 1 to 15 having a copper corrosion rating according to ASTM D4048 of 1 or 2.

17. Use in a grease composition comprising at least one polyol ester base oil and at least one fatty acid metal soap, at least one fluorinated polymer and at least one sulfur fatty acid ester the amount of active sulfur at 150 ° C. according to ASTM D1662 by mass provided by the sulfur-containing fatty acid ester being greater than or equal to 0.15%, relative to the total mass of fat composition, to improve Extreme pressure performance according to ASTM D2596 and / or DIN 51350/4 of the grease composition.