BR112014014506B1 - GREASE COMPOSITION - Google Patents

Abstract

Grease composition. 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 fluorine-containing polymer and at least one sulfurized fatty acid ester, the amount per mass of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester with respect to the total mass of the grease composition being greater than or equal to 0.15%

Description

Field of invention

[001] The present invention relates to grease compositions, specifically, grease compositions having a reduced environmental impact and exhibiting good extreme pressure and corrosion properties, specifically with respect to metals or metal alloys.

Technological history of the invention

[002] Recent times have seen the growing significance of environmental problems on a world scale and the exercise of terrestrial biosphere protection as a major challenge in all sectors of industry. The field of greases is no exception to the rule, the risk of pollution of water courses and soils, which is represented, specifically, by discarding the natural environment of base oils, the main ingredients of these products, means that the current progress is expected with these oils, specifically in the area of biodegradability, for uses that involve the risk of external leakage of greases. At the same time, progressively powerful machinery is subject to demands under even more severe conditions and, in addition, to biodegradability, for example, its lubrication products are required to show significant performance improvements in terms of extreme pressure and corrosion properties.

[003] US 6,316,392 describes a grease composition having an improved corrosion resistance and comprising at least one base oil, a fatty acid metal soap and an extreme pressure additive that can be chosen from a sulfurized fatty acid ester or PTFE. However, the compositions described in this document do not include the specific combination of a fluorine-containing polymer and a sulfurized fatty acid ester. Furthermore, this document does not provide any indication regarding the amount of active sulfur supplied by the sulfurized fatty acid ester.

[004] The present invention relates to a grease composition that can be used in devices that present a risk of external grease leakage, such as automobiles, construction machinery or agricultural equipment, while at the same time having an environmental impact reduced, good performance under extreme pressure and low corrosion to metals or metal alloys.

[005] Surprisingly, the depositor observed that a grease composition having a specific combination of a sulfurized fatty acid ester, said ester providing a certain amount of active sulfur at 150 ° C according to ASTM D1662, and a fluorine-containing polymer, in a base oil of the polyol ester type, has very good properties of extreme pressure, it is not corrosive specifically to metals or metal alloys, specifically copper, while having a reduced environmental impact.

Brief description of the invention

[006] 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 fluorine-containing polymer and at least one fatty acid ester sulfurized, the amount by mass of the active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester with respect to the total mass of the grease composition being greater than or equal to 0.15%.

[007] Preferably, the polyol ester is chosen from neopentylglycol esters, trimethylolethane esters, trimethylolpropane esters, pentaerythritol esters and / or dipentaerythritol esters, used alone or in a mixture.

[008] Preferably, the composition comprises from 50 to 95% by weight with respect to the total mass of the grease composition of a base oil of the polyol ester type, preferably from 60 to 90%, more preferably from from 70 to 80%.

[009] Preferably, the fluorine-containing polymer is polytetrafluoroethylene.

[0010] Preferably, the composition comprises from 1 to 10% by weight of the fluorine-containing polymer with respect to the total mass of the grease composition, preferably from 2 to 8%, more preferably from 3 to 5% .

[0011] Preferably, the sulfurized fatty acid ester is a fatty acid triglyceride and / or a methyl fatty acid ester, used alone or in a mixture.

[0012] Preferably, the composition comprises from 0.5 to 5% by weight of the sulfurized fatty acid ester with respect to the total mass of the grease composition, preferably from 1 to 4%, more preferably from 2 to 3%.

[0013] Preferably, the fatty acid metal soap is a simple fatty acid metal soap, preferably of lithium or calcium.

[0014] Preferably, the fatty acid metal soap is lithium 12-hydroxystearate.

[0015] Preferably, the composition comprises from 1 to 20% by weight with respect to the total mass of the fatty acid metal soap grease composition, preferably from 2 to 15%, preferably from 4 to 12 %.

[0016] Preferably, the polyol ester, or mixture of polyol esters, has a kinematic viscosity at 40 ° C, measured according to the ASTM D 445 standard, between 3 and 2000 cSt, preferably between 10 and 1500 cSt, more preferably between 40 and 500 cSt, even more preferably between 50 and 200 cSt.

[0017] Preferably, the composition has a consistency according to the ASTM D217 standard comprised between 220 and 430 tenths of a millimeter, preferably between 265 and 295 tenths of a millimeter.

[0018] Preferably, the amount per mass of the active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester, with respect to the total mass of the grease composition, is greater than or equal to 0.15% per mass, preferably greater than or equal to 0.18%, more preferably greater than or equal to 0.20%.

[0019] Preferably, the composition has a welding load according to the ASTM D2596 standard greater than 315 kg, preferably greater than or equal to 400 kg.

[0020] 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.

[0021] Preferably, the composition has a corrosion rating for copper according to ASTM D4048 of 1 or 2.

[0022] The invention also relates to 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 fluorine-containing polymer and at least one ester of sulfurized fatty acid, the amount by mass of the active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester being greater than or equal to 0.15%, with respect to the total mass of the grease composition, with the purpose of improving extreme pressure performance according to the ASTM D2596 and / or DIN 51350/4 standards of the grease composition.

Detailed Description Sulfurized fatty acid ester

[0023] The grease according to the invention comprises at least one sulfurized fatty acid ester.

[0024] Sulfurized fatty acid esters are obtained by sulfurizing the fatty acid esters. Said fatty acid esters are obtained by reaction between one or more fatty acids and alcohols of all types or by transesterification between one or more fatty acid esters and alcohols of all types. By sulfurized fatty acid ester is meant an ester of at least one sulfurized fatty acid, it being understood that this is normally an ester of a sulfurized mixture of fatty acids.

[0025] 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 preferably from 16 to 20 carbon atoms. Fatty acids comprising 18 carbon atoms are the majority of fatty acids, i.e., they are present in a mass concentration of at least 50% ∞m relative to the total mass of the sulfurized fatty acid ester.

[0026] Sulfurized fatty acid esters can be sulfurized fatty acid monoesters, sulfurized fatty acid diesters, sulfurized fatty acid triesters or sulfurized fatty acid polyesters, used alone or in a mixture.

[0027] Preferred sulfurized fatty acid monoesters are C1-C4 alkyl monoesters, such as 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 methyl sulfurized fatty acid ester.

[0028] As an example of sulfurized fatty acid triesters, mention can be made of the sulfurized fatty acid triglycerides which will be totally or partially esterified and, therefore, in addition to the triesters, they will optionally comprise diesters and / or monoesters.

[0029] As an example of sulfurized fatty acid polyesters, pentaerythritol sulfurized fatty acid esters can be mentioned.

[0030] An advantage of the invention is to provide a grease composition free of sulfurized olefins and / or polysulfides. Sulfurized fatty acid esters have a reduced environmental impact, as these are compounds originating from renewable resources (fatty substances and fatty acids) that contain a significant proportion of renewable carbon. This is not the case for sulfurized olefins that are obtained by sulfurizing olefins, products of hydrocarbon origin and polysulfides that are also obtained when sulfurizing hydrocarbon source materials. It is noteworthy to note that the good extreme pressure performance was achieved using sulfurized fatty acid esters instead of sulfurized olefins or polysulfides, which are known to have better extreme pressure properties, this being made possible specifically due to the additional presence of a polymer containing fluorine in the grease composition.

[0031] By "active sulfur" is meant within the meaning of the present invention, the sulfur that a chemical compound is able to give up or release when that compound is placed under the conditions of the ASTM D1662 standard. The ASTM D-1662 standard defines an active sulfur level of a compound at a given temperature as a difference expressed as a weighted percentage of the sulfur content before and after reacting a sample of that sulfurized compound with a certain amount of copper for a defined time.

[0032] The amount of active sulfur at 150 ° C (ASTM D1662 standard) in the grease composition is one of the parameters that is important to achieve good performance, specifically under extreme pressure. This amount of active sulfur at 150 ° C (ASTM D1662) in the grease composition must not be too low, or it is not possible to achieve satisfactory extreme pressure behavior. It must not be too high, or problems will arise from grease corrosion, specifically to metals and metal alloys, specifically to copper; neither a very high amount of active sulfur at 150 ° C (ASTM D1662) in the absence of the fluorine-containing polymer provides good performance, specifically under extreme pressure.

[0033] Preferably, the amount of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester in the grease composition is greater than or equal to 0.15% by weight with respect to the total mass of the composition of grease, preferably greater than or equal to 0.18%, more preferably greater than or equal to 0.20%.

[0034] Preferably, the amount of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester in the grease composition is less than or equal to 5% by weight with respect to the total mass of the 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%.

[0035] Preferably, the amount of sulfur according to ASTM D2622 provided by the sulfurized fatty acid ester in the grease composition is greater than 0.3% by weight with respect to the total mass of the grease composition, preferably greater than or equal to 0.34%.

[0036] Preferably, the grease composition comprises from 0.5 to 5% by weight with respect to the total mass of the grease composition of the sulfurized fatty acid ester, preferably from 1 to 4%, more preferably from from 2 to 3%.

[0037] Preferably, the grease composition according to the invention comprises at least two different sulfurized fatty acid esters, for the purpose of improving extreme pressure performance, preferably at least one sulfurized fatty acid methyl ester and at least one sulfurized fatty acid triglyceride. For a given amount of active sulfur at 150 ° C, the combination of two different sulfurized fatty acid esters, specifically a sulfurized fatty acid methyl ester and a sulfurized fatty acid triglyceride, makes it possible to improve extreme pressure performance due to non-sulfur be released in the same way. The less blocked ester, such as the sulfurized fatty acid methyl ester, will be the fastest to release the active sulfur, so the more blocked ester, such as the sulfurized fatty acid triglyceride, will take turns.

[0038] The sulfurized fatty acid esters used in the present invention are products that are commercially available, for example, from suppliers PCAS, King Industries, Dover, Magna, Arkema,

Rhein Chemie. Fluorine-containing polymer

[0039] The grease compositions according to the invention comprise at least one fluorine-containing polymer> fluoropolymer, an essential element of the invention to achieve good extreme pressure performance.

[0040] Fluoropolymers are chosen from polytetrafluoroethylenes or PTFE, poly (tetrafluoroethylene / hexafluoropropene) or FEP, poly (tetrafluoroethylene / vinyl perfluorinated ethers) or PFA, perfluorinated polyethers, poly (chlorotrifluoroethylene) or poly (chlorotrifluoroethylene) or PCT PVDF, poly (ethylene / tetrafluoroethylene) or ETFE, poly (ethylene / chlorotrifluoroethylene) or ECTFE, poly (vinyl fluoride) or PVF, poly (vinyl fluoride / hexafluoropropene), poly (tetrafluoroethylene / vinyl perfluorinated ether), poly (tetrafluoroethylene) ), fluorosilicones, polyfluorophosphates.

[0041] Preferably, the fluoropolymer consists exclusively of carbon atoms and fluorine atoms.

[0042] Preferably, the fluoropolymer is a polytetrafluoroethylene.

[0043] Preferably, the polytetrafluoroethylene has an average particle size comprised between 0.1 and 100 Dm, preferably between 0.2 and 50, more preferably between 0.2 and 10, even more preferably between 0.2 and 5, still more preferably between 0.2 and 1, even more preferably between 0.2 and 0.5.

[0044] The grease composition according to the invention comprises from 1 to 10% by mass of the fluorine-containing polymer in relation to the total mass of the grease composition, preferably from 2 to 8%, more preferably from 3 to 5%. A smaller amount of fluoropolymer will not allow good performance of extreme pressure to be achieved, while a larger amount would have a negative environmental impact.

[0045] The fluorine-containing polymers used in the present invention are products that are commercially available, for example, from suppliers Dupont, Solvay, Maflon, Xeon, Shamrock.

Base oil of the polyol ester type

[0046] The grease composition according to the invention comprises at least one base oil of renewable origin based on a polyol ester.

[0047] The polyol esters that can be used as the base oil are diesters, triesters, tetraesters or complex esters comprising more than four ester functions.

[0048] The acids that can be used to form the esters are monocarboxylic acids or dicarboxylic acids.

[0049] Preferably, monocarboxylic acids have from 3 to 22 carbon atoms, more preferably from 4 to 20, even more preferably from 6 to 18, even more preferably from 8 to 16, even more preferably from 10 to 12.

[0050] There may be mentioned, for example, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, isooctanoic acid, nonanoic acid, decanoic acid, isodecanoic acid, oleic acid, stearic acid. Preferably, saturated acids containing no unsaturation are used.

[0051] Preferably, dicarboxylic acids have from 3 to 22 carbon atoms, more preferably from 4 to 20, even more preferably from 6 to 18, even more preferably from 8 to 16, even more preferably from 10 to 12. For example, succinic acid, adipic acid, azelaic acid, sebacic acid can be mentioned.

[0052] The alcohols that can be used to form the esters are monoalcohols (formation of diesters with dicarboxylic acids), di-alcohols, tri-alcohols or tetra-alcohols. Preferred alcohols are polyols, such as, neopentylglycol, trimethylolpropane, pentaerythritol.

[0053] In order to obtain sufficient biodegradability, the grease composition according to the invention comprises from 50 to 95% by weight with respect to the total mass of the polyol ester grease composition, preferably from 60 to 90%, more preferably from 70 to 80%.

[0054] These ester type base oils are chosen for their negligible environmental impact in contrast to base oils originating from petroleum that are conventionally used. Although the use of such base oils of the polyol ester type has a negative impact on the properties of extreme pressure, since these base oils of the polyol ester type likewise have a tendency to migrate to the surface of the lubricated parts and are in competition with the other additives, consequently, the use of the specific combination of fluoropolymer and sulfurized fatty acid ester.

[0055] 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 (ASTM D445 standard), preferably between 10 and 1500 cSt , more preferably between 20 and 1000 cSt, even more preferably between 40 and 500 cSt, even more preferably between 50 and 200 cSt. These viscosity variations, specifically from 50 to 200 cSt, make it possible to achieve a good compromise between extreme pressure performance and biodegradability.

[0056] The base oils used in the present invention are products that are commercially available, for example, from suppliers Uniqema, Croda, Oléon, Akzo, Nyco.

Soaps

[0057] The grease compositions according to the invention are thickened with fatty acid metal soap, 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).

[0058] These thickening agents are the products commonly used in the field of greases, easily available and economical. Greases thickened with fatty acid metal soap have very good mechanical stability, compared, for example, with greases comprising polyurea-based thickening agents, which allows easy use in applications where grease is applied in a non-stick space. confined. In addition, polyureas are prepared from isocyanate, an extremely toxic compound. It is therefore not desirable to use thickeners based on polyureas in order to obtain a grease that is biodegradable, non-toxic and free of products classified under CLP Regulation (EC) No. 1272/2008. The grease according to the invention is, therefore, free of thickeners based on polyurea and, therefore, comprises only thickeners of the fatty acid metal soap type.

[0059] Preferably, long-chain fatty acids are used, typically comprising from 10 to 28 carbon atoms, saturated or unsaturated, optionally hydroxylated.

[0060] 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, arachidonium acid, behenic acid, oleic, linoleic acid, erucic acid and its hydroxylated derivatives. 12-hydroxystearic acid, the best known derivative in this category, is preferred. Lithium 12-hydroxystearate is the preferred thickening agent.

[0061] 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, etc.).

[0062] Soaps known as simple soaps can be formed by using one or more long-chain fatty acids. Simple soaps are preferred over complex soaps, as they are more easily biodegradable and do not accumulate biologically.

[0063] Soaps known as complex soaps can also be formed by using one or more long-chain fatty acids in combination with one or more carboxylic acids with short hydrocarbon chains comprising a maximum of 8 carbon atoms.

[0064] The saponification agent used to produce the soap can be a metallic compound of lithium, sodium, calcium, aluminum; preferably lithium and calcium, and preferably a hydroxide, oxide or carbonate of these metals.

[0065] One or more metallic compounds, having or not the same metallic cation, can be used in the greases according to the invention. In this way, it is possible to use lithium soaps in combination with calcium soaps in a smaller proportion.

[0066] Metal soaps are used in the content of the order of 1 to 20% by weight with respect to the total mass of the grease composition, preferably from 2 to 15%, preferably from 4 to 12%.

Process for preparing greases

[0067] Greases according to the invention are produced by forming the metal soap in situ or using a preformed soap.

[0068] The process for preparing the grease when forming the metal soap in situ is as follows.

[0069] One or more long-chain or short-chain fatty acids are dissolved in a fraction of the base oil or mixture of the base oil at a temperature between 80 ° C and 90 ° C. This fraction is generally in the range of 40% to 60% by mass of the total amount of oil contained in the final grease.

[0070] Then, the metallic compounds are added at the same temperature, preferably of the type of metal oxide, hydroxide or carbonate.

[0071] In this way, it is possible to add a single type of metal or combine several metals. The preferred metal of the compositions according to the invention is lithium, optionally combined, in a lesser proportion, with calcium.

[0072] The saponification reaction of 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.

[0073] The formed water is then evaporated by heating the mixture to a temperature of approximately 100 ° C to 200 ° C.

[0074] The grease is then cooled by the remaining fraction of the base oil.

[0075] Then, at approximately 80 ° C, the fluorine-containing polymer and the sulfurized fatty acid ester and any other additives are incorporated.

[0076] Stirring is then carried out for a sufficient time in order to obtain a grease composition, which is then ground in order to improve its uniformity.

[0077] The process for preparing the grease with the preformed metal soap is identical, except 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.

[0078] The consistency of a grease measures its stiffness or fluidity at rest. A numerical value is designated by the depth of penetration of a cone of certain dimensions and weight. The grease is subjected to the previous mixture. The conditions for measuring the consistency of a grease are defined by the ASTM D 217 standard.

Grease consistency

[0079] According to their consistency, greases are divided into 9 grades or 9 degrees of NLGI (National Lubrication Grease Institute) commonly used in the field of greases. These degrees are indicated in the table below.

[0080] Preferably, the greases according to the invention have a consistency between 220 and 430 tenths of a millimeter according to the ASTM D217 standard, covering grades 00, 0,1,2 and 3.

[0081] Preferably, the greases according to the invention have a consistency between 265 and 295 tenths of a millimeter according to the ASTM D217 standard, to cover grade 2.

Other additives

[0082] The grease compositions according to the invention may also contain antioxidant additives, for example, antioxidants of the phenolic type, anti-corrosion additives, such as, for example, oxidized waxes or amine phosphates, corrosion inhibitor additives, such as, derivatives of tolyltriazoles or dimercaptotiadiazole.

Technical performance of greases

[0083] The grease compositions according to the invention have good extreme pressure performance. Specifically, the grease compositions according to the invention have a welding load measured in accordance with the ASTM D2596 standard greater than 315 kg, preferably greater than or equal to 400 kg. Specifically, the grease compositions according to the invention have a welding 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.

[0084] The grease compositions according to the invention are also only slightly corrosive, specifically to metals and metal alloys, and more particularly to copper. Specifically, the grease compositions according to the invention stain copper tape only lightly (classification 1 according to ASTM D4048) or stain copper tapes only moderately (classification 2 according to ASTM D4048).

[0085] 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. Specifically, the greases according to the invention are biodegradable, do not accumulate biologically, are not toxic to aquatic environments and are renewable.

[0086] Preferably, the grease compositions according to the invention contain additives that are not dangerous to the environment and human health.

[0087] Preferably, the grease compositions according to the invention are free of organic halogenated compounds, nitrite-type compounds, metals or metallic compounds, except sodium, potassium, magnesium, calcium, lithium and / or aluminum.

[0088] Preferably, the grease compositions according to the invention are not toxic to the aquatic environment.

[0089] Specifically, the grease compositions according to the invention have an aquatic toxicity to algae, daphnia and fish of at least 1000 mg / l according to OECD standards 201,202 and 203.

[0090] Similarly, the main constituents of grease, ie those present in more than 5% by mass with respect to the total mass of the grease composition, such as base oil and soap, have an aquatic toxicity for seaweed and daphnia of at least 100 mg / l according to OECD standards 201 and 202.

[0091] Similarly, when a constituent has an aquatic toxicity to algae and daphnia of at least 100 mg / l according to OECD standards 201 and 202 (category D), said constituent can be present in the grease in any concentration. The grease compositions according to the invention have a concentration by mass of constituents having an aquatic toxicity for algae and daphnia comprised between 10 mg / l and 100 mg / l according to OECD 201 and 202 (category E), lower or equal to 25%. The grease compositions according to the invention have a concentration by mass of constituents having an aquatic toxicity for algae and daphnia comprised between 1 mg / l and 10 mg / l according to OECD 201 and 202 (category F), lower or equal to 2%, preferably less than or equal to 1%. This only refers to the constituents of the grease whose concentration per mass in the grease is greater than or equal to 0.1%.

[0092] The grease compositions according to the invention are biodegradable and do not accumulate biologically. Specifically, the grease compositions according to the invention have a mass concentration of constituents that are finally biodegradable in an aerobic medium (category A according to OECD 301A-F, OECD 306, OECD 301) over 75%, a mass concentration of constituents that are intrinsically biodegradable in an aerobic medium (category B according to OECD 302B, OECD 302C) or of non-biodegradable constituents and those that do not accumulate biologically (category C) less than or equal to 25% , and a concentration by mass of non-biodegradable constituents and those that accumulate biologically (category X) less than or equal to 0.1%. This only refers to the constituents of the grease whose concentration per mass in the grease is greater than or equal to 0.1%.

[0093] The grease compositions according to the invention contain at least 45% by weight with respect to the total mass of the carbon grease composition originating from renewable raw materials.

[0094] The invention also relates to a lubrication process using the grease compositions described above. The process consists of contacting the parts to be lubricated with the grease compositions described above.

Examples

[0095] Different grease compositions are prepared from:

[0096] - lithium 12-hydroxystearate (thickening agent). Its aquatic toxicity to algae and daphnia is above 100 mg / l in accordance with OECD standards 201 and 202 (category D). Its biodegradability is equal to 83.8% according to OECD 301B (category A).

[0097] - polytetrafluoroethylene (PTFE). Its aquatic toxicity for algae and daphnia is above 100 mg / l according to OECD 201 and 202 (category D). Its biodegradability is category C according to the OECD 301B standard.

[0098] sulfurized fatty acid methyl ester (sulfurized ester 1), comprising 17% by mass of sulfur with respect to the total mass of sulfurized ester and 48% by mass of sulfur active at 150 ° C with respect to the total mass of ester sulfurized. Its aquatic toxicity to seaweed and daphnia is comprised between 10 mg / l and 100 mg / l according to OECD standards 201 and 202 (category E). Its biodegradability is category C according to the OECD 301B standard. It comprises 95% by mass of renewable carbon with respect to the total mass of the sulfurized ester.

[0099] - sulfurized fatty acid triglycerides (sulfurized ester 2), comprising 15% by mass of sulfur with respect to the total mass of sulfurized ester and 33% by mass of sulfur active at 150 ° C with respect to the total mass of sulfurized ester . 60% by weight of the sulfurized ester in relation to the total mass of the sulfurized ester has an aquatic toxicity for algae and daphnia between 10 mg / l and 100 mg / l according to OECD standards 201 and 202 (category E) and 40% per mass of the sulfurized ester it has an aquatic toxicity for algae and daphnia between 1 mg / l and 10 mg / l according to OECD standards 201 and 202 (category E). Its biodegradability is category C according to the OECD 301B standard. It comprises 95% by mass of the renewable carbon in relation to the total mass of the sulfurized ester.

[00100] -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 for algae and daphnia is above 100 mg / l according to OECD 201 and 202 (category D). Its biodegradability is equal to 79% according to OECD 301B (category A). It comprises 81% by mass of the renewable carbon in relation to the total mass of the sulfurized ester.

[00101] -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 for algae and daphnia is above 100 mg / l according to OECD 201 and 202 (category D). Its biodegradability is equal to 67% according to OECD 301B (category A). It comprises 55% by weight of the renewable carbon in relation to the total mass of the sulfurized ester.

[00102] - 4,4'-methylene bis 2,6-di-tertiary-butylphenol (antioxidant 1),

[00103] -Octadecyl 3- (3,5-dithertiobutyl-4-hydroxyphenyl) propanoate (antioxidant 2). Its aquatic toxicity for algae and daphnia is above 100 mg / l according to OECD 201 and 202 (category D). Its biodegradability is category B according to the OECD 301B standard.

[00104] -Rusted hydrocarbon waxes (corrosion inhibitor 1). Its aquatic toxicity to algae and daphnia is comprised between 10 mg / l and 100 mg / l according to OECD standards 201 and 202 (category E). Its biodegradability is equal to 55% according to OECD 301B (category B).

[00105] - Tolyltriazole (corrosion inhibitor 2). Its aquatic toxicity to algae and daphnia is comprised between 1 mg / l and 10 mg / l according to OECD standards 201 and 202 (category F). Its biodegradability is equal to 4% according to OECD 301B (category C).

[00106] In the proportions (% by mass) of the following Table I:

[00107] Table I - Composition by mass of greases

[00108] The control greases and greases according to the invention have the following biochemical characteristics (Table II):

[00109] Table II - Biochemical characteristics of greases

[00110] These grease compositions were subjected to extreme pressure and corrosion tests (Table III).

(1)ASTM D2596 (2) DIN 51350/4 (3) ASTM D4048[00111] Table III - Performance of extreme pressure and corrosion of greases

(1) ASTM D2596 (2) DIN 51350/4 (3) ASTM D4048

[00112] It is observed that the control grease composition 1 has a very mediocre welding load of 160 kg (ASTM D2596) or 160 daN (DIN 51350/4). The presence of PTFE in the grease composition is not sufficient to provide good properties of extreme pressure.

[00113] It is observed that the control grease composition 5 has a low welding load of 315 kg (ASTM D2596) or 300 daN (DIN 51350/4). The presence of the sulfurized fatty acid ester alone in the grease composition is not sufficient to guarantee good extreme pressure properties.

[00114] When 2% sulfurized ester 2 is added, the welding load is slightly improved, since it is 315 kg (ASTM D2596) or 300 daN (DIN 51350/4) in the control grease composition 3, but still insufficient due to the amount of active sulfur at 150 ° C being very low.

[00115] The presence of 4% of sulfurized ester 2 and PTFE in the grease composition according to invention 2 makes it possible to achieve a welding load of 400 kg (ASTM D2596) or 360 daN (DIN 51350/4).

[00116] The combination of 2% sulfurized ester 1 and PTFE in the grease composition according to invention 4 thus makes it possible to achieve a welding load of 400 kg (ASTM D2596) or 340 daN (DIN 51350/4).

[00117] The results of control grease 6 show that the combination of a sulfurized fatty acid ester with PTFE alone is not sufficient to guarantee good extreme pressure properties, when the amount of active sulfur at 150 ° C according to the standard ASTM D1662 provided by the sulfurized fatty acid ester is less than 0.15%.

[00118] The grease according to invention 7 shows that a combination of a sulfurized fatty acid ester and PTFE in a grease composition, the amount of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the ester of sulfurized fatty acid being greater than or equal to 0.15%, makes it possible to improve the properties of extreme pressure.

[00119] Furthermore, the grease compositions according to the invention are only slightly corrosive to copper.

[00120] These results demonstrate that obtaining the high performance of extreme pressure is due to the presence of the fluorine-containing polymer in combination with a sulfurized fatty acid ester that provides the grease composition with an amount of active sulfur at 150 ° C greater than or equal to 0.15% by weight with respect to the total mass of the grease composition. This extreme pressure performance is paralleled by low grease corrosion and a grease that is biodegradable, does not accumulate biologically, is non-toxic and originates from renewable raw materials.

Claims (17)

1. Grease composition, characterized by comprising from 50 to 95% by weight in relation to the total mass of grease composition of at least one basic oil of the polyol ester type, from 1 to 20% by weight in relation to the total mass of the composition of grease of at least one fatty acid metal soap, from 1 to 10% by weight relative to the total mass of grease composition of at least one fluorine-containing polymer and from 0.5 to 5% by weight relative to the total mass of fat composition of at least one sulfurized fatty acid ester, the mass amount of active sulfur at 150 ° C according to ASTM D1662 standard provided by the sulfurized fatty acid ester in relation to the total mass of the grease composition being greater that or equal to 0.15%. 2. Composition according to claim 1, characterized by the fact that the polyol ester is chosen from neopentyl glycol 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, characterized by the fact that it comprises from 60 to 90% by weight with respect to the total mass of the grease composition of a base oil of the polyol ester type, preferably from from 70 to 80%. Composition according to claim 1, 2 or 3, characterized by the fact that the fluorine-containing polymer is polytetrafluoroethylene. Composition according to any one of claims 1 to 4, characterized in that it comprises from 2 to 8% by weight of the fluorine-containing polymer in relation to the total mass of the grease composition, preferably from 3 to 5 %. Composition according to any one of claims 1 to 5, characterized in that the sulfurized fatty acid ester is a fatty acid triglyceride and / or a methyl fatty acid ester, used alone or in a mixture. Composition according to any one of claims 1 to 6, characterized in that it comprises from 1 to 4% by weight of the sulfurized fatty acid ester in relation to the total mass of the grease composition, preferably from 2 up to 3%. Composition according to any one of claims 1 to 7, characterized in that the fatty acid metal soap is a simple fatty acid metal soap, preferably of lithium or calcium. Composition according to any one of claims 1 to 8, characterized in that the fatty acid metal soap is lithium 12-hydroxystearate. Composition according to any one of claims 1 to 9, characterized in that it comprises from 2 to 15% by mass with respect to the total mass of the fatty acid metal soap grease composition, preferably from 4 to 12%. 11. Composition according to any one of claims 1 to 10, characterized by the fact that the polyol ester, or the mixture of polyol esters, has a kinematic viscosity at 40 ° C, measured according to the ASTM D standard 445, between 3 and 2000 cSt, preferably between 10 and 1500 cSt, more preferably between 40 and 500 cSt, even more preferably between 50 and 200 cSt. Composition according to any one of claims 1 to 11, characterized in that it has a consistency according to the ASTM D217 standard comprised between 220 and 430 tenths of a millimeter, preferably between 265 and 295 tenths of a millimeter. 13. Composition according to any one of claims 1 to 12, characterized in that it comprises an amount per mass of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester in relation to the mass total grease composition, greater than or equal to 0.18% by weight, preferably greater than or equal to 0.20%. Composition according to any one of claims 1 to 13, characterized in that it has a welding load according to the ASTM D2596 standard greater than 315 kg, preferably greater than or equal to 400 kg. Composition according to any one of claims 1 to 14, characterized in that it 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. 16. Composition according to any one of claims 1 to 15, characterized by the fact that it has a copper corrosion rating according to ASTM D4048 of 1 or 2. 17. Use in a grease composition defined in claim 1, characterized in that it comprises at least one base oil of the polyol ester type and at least one fatty acid metal soap, at least one fluorine-containing polymer and at least one sulfurized fatty acid ester, the amount per mass of active sulfur at 150 ° C according to the ASTM D1662 standard provided by the sulfurized fatty acid ester being greater than or equal to 0.15% with respect to the total mass of the grease composition, for the purpose of improving extreme pressure performance in accordance with ASTM D2596 and / or DIN 51350/4