EP2791297B1 - Grease composition - Google Patents

Description

Field of the invention

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

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 problem in all sectors of industry. The field of greases is no exception to the rule, and the risk of pollution of water and soil represented in particular by the release into the nature of base oils, main ingredients of these products, justifies that we expect today to the latter that they are making progress in the field, in particular in terms of biodegradability for uses which involve the risk of external leakage of grease. At the same time, the ever more powerful machines are subjected to increasingly severe conditions and require from their lubrication products, in addition to biodegradability for example, significant performance gains in terms of properties. extreme pressure and corrosion.

The document JP 2008/208240 a relates to grease compositions having good biodegradability, good extreme pressure properties and good stability to thermal oxidation. However, this document makes no mention of a fat composition associating a sulfur fatty acid ester with at least one fluoropolymer.

The document US 6,316,392 describes a grease composition having improved corrosion resistance and comprising at least one base oil, a metallic soap of fatty acid and an extreme pressure additive which can be chosen from an ester of sulfur-containing fatty acid or of PTFE. However, the compositions described in this document do not include the specific combination of a fluoropolymer 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 which can be used in devices comprising risks of external grease leaks such as cars, construction machines or agricultural equipment, and which has both a reduced impact on the environment, good performance under extreme pressure and low corrosion towards metals or metal alloys.

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

Brief description of the invention

The present application describes a fat composition comprising at least one base oil of polyol ester type, at least one metallic soap of fatty acid, at least one fluorinated polymer and at least one ester of sulfur fatty acid, the amount of sulfur active at 150 ° C. according to standard ASTM D1662 by mass supplied by the sulfur fatty acid ester, relative to the total mass of fat composition, being greater than or equal to 0.15%.

More particularly, the invention relates to a fat composition comprising from 50 to 95% by mass, relative to the total mass of the composition, of at least one base oil of polyol ester type, from 1 to 20% by weight. mass, relative to the total mass of the composition, of at least one fatty acid metal soap, from 1 to 10% by mass, relative to the total mass of the composition, of at least one fluoropolymer and from 0.5 to 5% by mass, relative to the total mass of the composition, of at least one sulfur fatty acid ester, the amount of active sulfur at 150 ° C. according to standard ASTM D1662 by mass provided by the sulfur fatty acid ester, 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.

As mentioned previously, the composition comprises from 50 to 95% by mass, relative to the total mass of fat composition, of a base oil of the polyol ester type, preferably from 60 to 90%, more preferably from 70 at 80%.

Preferably, the fluoropolymer is polytetrafluoroethylene.

As mentioned previously, the composition comprises from 1 to 10% by mass of fluoropolymer, relative to the total mass of grease 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.

As mentioned previously, the composition comprises from 0.5 to 5% by mass of sulfur-containing 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 metallic soap is a simple fatty acid metallic soap, preferably lithium or calcium.

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

As mentioned above, the composition comprises from 1 to 20% by mass, relative to the total mass of the fat composition, of metallic soap of fatty acid, 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 standard ASTM D 445, of 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.

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

Preferably, the quantity of active sulfur at 150 ° C. according to standard ASTM D1662 by 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 mass, 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 standard ASTM D2596 greater than 315 kg, preferably greater than or equal to 400 kg.

Preferably, the composition has a solder 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 corrosion classification with respect to copper 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 polyol ester type and at least one metallic soap of fatty acid, of at least one fluorinated polymer and of at least one ester. sulfur fatty acid, the amount of active sulfur at 150 ° C according to standard ASTM D1662 by mass provided by the sulfur fatty acid ester being greater than or equal to 0.15%, relative to the total mass of composition grease, to improve the extreme pressure performance according to the ASTM D2596 and / or DIN 51350/4 standards of the grease composition.

detailed description Sulfur fatty acid ester

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

The sulfur 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 fatty acid esters and alcohols of all kinds. By sulfur fatty acid ester is meant an ester of at least one sulfur fatty acid, it being understood that it is most of the time an ester of a mixture of sulfur fatty acids.

The fatty acids which can be used to form the sulfur 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 at a mass concentration of at least 50% relative to the total mass of sulfur fatty acid ester .

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

Preferred sulfur fatty acid monoesters are C ₁ -C ₄ alkyl monoesters, such as methyl monoesters, ethyl monoesters, n -propyl monoesters, i -propyl monoesters, monoesters of n -butyl, monoesters of s -butyl, monoesters of t -butyl. Preferably, the monoester is a methyl monoester. Preferably the sulfur fatty acid ester is a methyl fatty acid ester.

As an example of sulfur fatty acid triesters, mention may be made of sulfur fatty acid triglycerides which will be completely or partially esterified and will therefore possibly also comprise, in addition, triesters, diesters and / or monoesters.

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

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

“Active sulfur” is understood to mean, within the meaning of the present invention, the sulfur that a chemical compound is capable of yielding or releasing when this compound is placed under the conditions of standard ASTM D1662. ASTM D-1662 defines an active sulfur level of a compound at a given temperature as a difference expressed as a percentage by weight of sulfur content before and after reaction of a sample of this sulfur-containing compound with a given quantity of copper during a fixed time.

The quantity of active sulfur at 150 ° C. (ASTM D1662 standard) in the grease composition is one of the important parameters for obtaining good performance, in particular at extreme pressure. This amount of active sulfur at 150 ° C. (ASTM D1662) in the grease composition must not be too low, otherwise a satisfactory extreme pressure behavior cannot be obtained. It must not be too high, otherwise it is the corrosion of the grease, in particular with respect to metals and metal alloys, in particular with respect to copper, which is problematic and moreover an amount of active sulfur. at 150 ° C (ASTM D1662) too high without the presence of the fluoropolymer will also not give good performance, in particular at extreme pressure.

Preferably, the amount of active sulfur at 150 ° C. according to standard ASTM D 1662 provided by the sulfur fatty acid ester in the fat composition is greater than or equal to 0.15% by mass, 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 standard ASTM D 1662 provided by the sulfur fatty acid ester in the fat composition is less than or equal to 5% by mass, relative to the total mass of fat 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 standard ASTM D2622 provided by the sulfur fatty acid ester in the fat composition is greater than 0.3% by mass, relative to the total mass of fat composition, preferably greater than or equal to 0.34%.

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

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

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

Fluorinated polymer

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

The fluoropolymers are chosen from polytetrafluoroethylenes or PTFE, poly (tetrafluoroethylene / hexafluoropropene) or FEP, poly (tetrafluoroethylene / perfluorinated ethervinyl) or PFA, perfluorinated polyethers, poly (chlorotrifluoroethylene) or PCTFE, poly (fluoride) or PVDF, poly (ethylene / tetrafluoroethylene) or ETFE, poly (ethylene / chlorotrifluoroethylene) or ECTFE, poly (vinyl fluoride) or PVF, poly (vinylidene fluoride / hexafluoropropene), poly (tetrafluoroethylene / 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 an average particle size of between 0.1 and 100 μm, preferably between 0.2 and 50, more preferably between 0.2 and 10, even more preferably between 0.2 and 5, even more preferably between 0.2 and 1, even more preferably between 0.2 and 0.5.

The grease composition according to the invention comprises from 1 to 10% by mass of fluoropolymer, relative to the total mass of grease composition, preferably from 2 to 8%, more preferably from 3 to 5%. A lower 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 products available commercially, 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 oil, are diesters, triesters, tetraesters or complex esters comprising more than four ester functions.

The acids which 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, even more preferably from 6 to 18, even more preferably from 8 to 16, even more preferably from 10 to 12.

Mention may be made, for example, of hexanoic, octanoic, 2-ethylhexanoic, isooctanoic, nonanoic, decanoic, isodecanoic acids, oleic, stearic. Preferably saturated acids which do not contain unsaturations are 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, even more preferably from 8 to 16, even more preferably from 10 to 12. We can cite by example succinic, adipic, azelaic, sebacic acids.

The alcohols which 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.

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

These base oils of ester type are chosen for their negligible impact on the environment, unlike the base oils from petroleum conventionally used. However, the use 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 also tend to go to the surface of lubricated parts and compete with the other additives, hence the use of the specific combination of the fluoropolymer and the sulfur fatty acid ester.

The polyol ester base oil or the mixture of polyol ester base oils has a kinematic viscosity at 40 ° C. of between 3 and 2000 cSt (standard ASTM D445), 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 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 suppliers Uniqema, Croda, Oléon, Akzo, Nyco.

Soaps

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

These thickeners are products commonly used in the field of greases, readily available and inexpensive. Greases thickened with metallic fatty acid soaps have very good mechanical stability, compared, for example, to greases comprising thickeners based on polyureas, which allows easy use in applications where the fat is in an enclosure not confined. In addition, polyureas are prepared from isocyanate, an extremely toxic compound. It is therefore undesirable to use thickeners based on polyureas to obtain a biodegradable, non-toxic grease 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 only comprises thickeners of the metallic soap type of fatty acid.

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

Long chain fatty acids (typically comprising from 10 to 28 carbon atoms), are for example capric, lauric, myristic, palmitic, stearic, arachidic, behenic, oleic, linoleic, erucic acids, and their hydroxylated derivatives. 12-hydroxystearic acid is the best known derivative of this category, 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 ...).

Soaps known as simple can be formed using one or more long chain fatty acids. Simple soaps are preferred to complex soaps because they are more easily biodegradable and not bioaccumulative.

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

The saponification agent used to make 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.

One or more metallic compounds can be used, with or without the same metallic cation, in the greases according to the invention. We can thus combine lithium soaps, combined with calcium soaps in a lesser proportion.

The metallic soaps are used in contents of the order of 1 to 20% by mass, relative to the total mass of the fat composition, preferably from 2 to 15%, preferably from 4 to 12%.

Fat preparation process

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

The process for preparing the fat by forming the metallic 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 of the base oil mixture at a temperature between 80 ° C and 90 ° C. This fraction is generally of the order of 40% to 60% by mass of the total amount of oil contained in the final fat.

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

It is thus possible to add a single type of metal or to combine several metals. The preferred metal of the compositions according to the invention is lithium, optionally 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 water formed is then evaporated by cooking the mixture at a temperature of about 100 ° C to 200 ° C.

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

Then incorporated, at about 80 ° C, the fluoropolymer and the sulfur fatty acid ester, and any other additives.

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

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

Consistency of fats

Depending on their consistency, greases are divided into 9 classes or 9 NLGI (National Lubricating Grease Institute) classes commonly used in the field of greases. These grades are indicated in the table below. NLGI grade Consistency according to ASTM D 217 (tenth of a millimeter) 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 of between 220 and 430 tenths of a millimeter according to standard ASTM D217, to cover 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 standard ASTM D217, to cover grade 2.

Other additives

The grease compositions according to the invention may also contain antioxidant additives, for example antioxidants of the phenolic type, anti-rust additives, such as for example oxidized waxes or amine phosphates, anti-oxidant additives. corrosion 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 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 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 plates (classification 1 according to standard ASTM D4048) or only slightly tarnish the copper plates (classification 2 according to standard 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 fats according to the invention are biodegradable, not bio-accumulative, 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 from halogenated organic compounds, from nitrite-type compounds, from metals or from metallic 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 fat compositions according to the invention have an aquatic toxicity of at least 1000 mg / l on algae, daphnia and fish according to OECD standards 201, 202 and 203.

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

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

The grease compositions according to the invention are biodegradable and not bio-accumulative. In particular, the grease compositions according to the invention have a mass concentration of constituents which are ultimately biodegradable in aerobic medium (category A according to OECD standards 301A-F, OECD 306, OECD 301) greater than 75%, a mass concentration of constituents intrinsically biodegradable in aerobic environment (category B according to OECD 302B, OECD 302C standards) or non-biodegradable and non-bioaccumulative constituents (category C) less than or equal to 25%, and a mass concentration of non-biodegradable and accumulable constituents (category X ) less than or equal to 0.1%. This only concerns the constituents of fat whose mass concentration in fat is greater than or equal to 0.1%.

The fat compositions according to the invention contain at least 45% by mass, relative to the total mass of fat composition, of carbon originating from renewable raw materials.

The invention also relates to a method of lubrication using the grease compositions described above. The method of contacting the parts to be lubricated with the grease compositions described above.

Examples

• 12-hydroxystéarate de lithium (épaississant). Sa toxicité aquatique est supérieure à 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie D). Sa biodégradabilité est égale à 83,8% selon OCDE 301B (catégorie A).
• polytétrafluoroéthylène (PTFE). Sa toxicité aquatique est supérieure à 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie D). Sa biodégradabilité est de catégorie C selon la norme OCDE 301B.
• ester méthylique d'acide gras soufré (ester soufré 1), comprenant 17% en masse, par rapport à la masse totale d'ester soufré, de soufre et 48% en masse de soufre actif à 150°C par rapport à la masse totale d'ester soufré. Sa toxicité aquatique est comprise entre 10 mg/l et 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie E). Sa biodégradabilité est de catégorie C selon la norme OCDE 301B. Il comprend 95% en masse de carbone renouvelable, par rapport à la masse totale d'ester soufré.

- triglycérides d'acide gras soufré (ester soufré 2), comprenant 15% en masse, par rapport à la masse totale d'ester soufré, de soufre et 33% en masse de soufre actif à 150°C par rapport à la masse totale d'ester soufré. 60% en masse de l'ester soufré, par rapport à la masse totale d'ester soufré, a une toxicité aquatique comprise entre 10 mg/l et 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie E) et 40% en masse de l'ester soufré a une toxicité aquatique comprise entre 1 mg/l et 10 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie E). Sa biodégradabilité est de catégorie C selon la norme OCDE 301B. Il comprend 95% en masse de carbone renouvelable, par rapport à la masse totale d'ester soufré.
- ester de triméthylolpropane et d'acides gras saturés (huile de base 1). Sa viscosité cinématique à 100°C (ASTM D445) est de 4,4 cSt, sa viscosité cinématique à 40°C (ASTM D445) est de 19,6 cSt. Sa toxicité aquatique est supérieure à 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie D). Sa biodégradabilité est égale à 79% selon la norme OCDE 301B (catégorie A). Il comprend 81% en masse de carbone renouvelable, par rapport à la masse totale d'ester soufré.
- ester de triméthylolpropane et d'acides gras saturés (huile de base 2). Sa viscosité cinématique à 100°C (ASTM D445) est de 32,2 cSt et sa viscosité cinématique à 40°C (ASTM D445) est de 316 cSt. Sa toxicité aquatique est supérieure à 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie D). Sa biodégradabilité est égale à 67% selon la norme OCDE 301B (catégorie A). Il comprend 55% en masse de carbone renouvelable, par rapport à la masse totale d'ester soufré.
- 4,4'-méthylène bis 2,6-di-tertio-butylphénol (anti-oxydant 1),
- Octadécyl 3-(3,5-ditertiobutyl-4-hydroxyphényl) propanoate (anti-oxydant 2). Sa toxicité aquatique est supérieure à 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie D). Sa biodégradabilité est de catégorie B selon la norme OCDE 301B.
- Cires d'hydrocarbures oxydées (anti-corrosion 1). Sa toxicité aquatique est comprise entre 10 mg/l et 100 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie E). Sa biodégradabilité est égale à 55% selon la norme OCDE 301B (catégorie B).
- Tolyltriazole (anti-corrosion 2). Sa toxicité aquatique est comprise entre 1 mg/l et 10 mg/l sur les algues et les daphnies selon les normes OCDE 201 et 202 (catégorie F). Sa biodégradabilité est égale à 4% selon la norme OCDE 301B (catégorie C).
dans les proportions (% massiques) du Tableau I suivant : Tableau I - Composition massique des graisses Graisse Témoin 1 Graisse Invention 2 Graisse Témoin 3 Graisse Invention 4 Graisse Témoin 5 Huile de base 1 (%) 18,83 17,85 18,30 18,30 19,06 Huile de base 2 (%) 63,12 60,00 61,55 61,55 63,79 Epaississant (%) 10,96 10,96 10,96 10,96 10,96 Anti-oxydant 1 (%) 0,09 0,09 0,09 0,09 0,09 Anti-oxydant 2 (%) 1,00 1,00 1,00 1,00 1,00 Anti-corrosion 1 (%) 1,00 1,00 1,00 1,00 1,00 Anti-corrosion 2 (%) - 0,10 0,1 0,1 0,1 PTFE (%) 5,00 5,00 5,00 5,00 - Ester soufré 1 (%) - - - 2,00 - Ester soufré 2 (%) - 4,00 2,00 - 4,00 Graisse Témoin 6 Graisse Invention 7 Huile de base 1 (%) 18.17 18,32 Huile de base 2 (%) 61,18 61,68 Epaississant (%) 10,96 10,96 Anti-oxydant 1 (%) 0,09 0,09 Anti-oxydant 2 (%) 1,00 1,00 Anti-corrosion 1 (%) 1,00 1,00 Anti-corrosion 2 (%) 0,10 0,10 PTFE (%) 5,00 5,00 Ester soufré 1 (%) 1,85 Ester soufré 2 (%) 2,50 Different fat compositions are prepared from:

• Lithium 12-hydroxystearate (thickener). Its aquatic toxicity is greater than 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category D). Its biodegradability is equal to 83.8% according to OECD 301B (category A).
• polytetrafluoroethylene (PTFE). Its aquatic toxicity is greater than 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category D). Its biodegradability is category C according to OECD standard 301B.
• sulfur fatty acid methyl ester (sulfur ester 1), comprising 17% by mass, relative to the total mass of sulfur ester, of sulfur and 48% by mass of active sulfur at 150 ° C. relative to the total mass of sulfur ester. Its aquatic toxicity is between 10 mg / l and 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category E). Its biodegradability is category C according to OECD standard 301B. he includes 95% by mass of renewable carbon, based on the total mass of sulfur ester.

- sulfur fatty acid triglycerides (sulfur ester 2), comprising 15% by mass, relative to the total mass of sulfur ester, sulfur and 33% by mass of active sulfur at 150 ° C relative to the total mass of sulfur ester. 60% by mass of the sulfur ester, relative to the total mass of sulfur ester, has an aquatic toxicity of between 10 mg / l and 100 mg / l on algae and daphnia according to OECD standards 201 and 202 ( category E) and 40% by mass of the sulfur-containing ester has an aquatic toxicity of between 1 mg / l and 10 mg / l on algae and daphnia according to OECD standards 201 and 202 (category E). Its biodegradability is category C according to OECD standard 301B. It comprises 95% by mass of renewable carbon, relative to the total mass of sulfur 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 is greater than 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category D). Its biodegradability is equal to 79% according to OECD standard 301B (category A). It comprises 81% by mass of renewable carbon, relative to the total mass of sulfur 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 is greater than 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category D). Its biodegradability is equal to 67% according to OECD standard 301B (category A). It comprises 55% by mass of renewable carbon, relative to the total mass of sulfur ester.
- 4,4'-methylene bis 2,6-di-tertio-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 daphnia according to OECD standards 201 and 202 (category D). Its biodegradability is category B according to OECD standard 301B.
- Oxidized hydrocarbon waxes (anti-corrosion 1). Its aquatic toxicity is between 10 mg / l and 100 mg / l on algae and daphnia according to OECD standards 201 and 202 (category E). Its biodegradability is equal to 55% according to OECD standard 301B (category B).
- Tolyltriazole (anti-corrosion 2). Its aquatic toxicity is between 1 mg / l and 10 mg / l on algae and daphnia according to OECD standards 201 and 202 (category F). Its biodegradability is equal to 4% according to OECD standard 301B (category C).
in the proportions (% by mass) of Table I below: Table I - Mass composition of fats Fat Control 1 Fat Invention 2 Fat Witness 3 Fat Invention 4 Fat Witness 5 Base oil 1 (%) 18.83 17.85 18.30 18.30 19.06 Base oil 2 (%) 63.12 60.00 61.55 61.55 63.79 Thickener (%) 10.96 10.96 10.96 10.96 10.96 Antioxidant 1 (%) 0.09 0.09 0.09 0.09 0.09 Antioxidant 2 (%) 1.00 1.00 1.00 1.00 1.00 Anti-corrosion 1 (%) 1.00 1.00 1.00 1.00 1.00 Anti-corrosion 2 (%) - 0.10 0.1 0.1 0.1 PTFE (%) 5.00 5.00 5.00 5.00 - Sulfurized ester 1 (%) - - - 2.00 - Ester sulfur 2 (%) - 4.00 2.00 - 4.00 Fat Witness 6 Fat Invention 7 Base oil 1 (%) 18.17 18.32 Base oil 2 (%) 61.18 61.68 Thickener (%) 10.96 10.96 Antioxidant 1 (%) 0.09 0.09 Antioxidant 2 (%) 1.00 1.00 Anti-corrosion 1 (%) 1.00 1.00 Anti-corrosion 2 (%) 0.10 0.10 PTFE (%) 5.00 5.00 Sulfurized ester 1 (%) 1.85 Ester sulfur 2 (%) 2.50

The control fats and according to the invention have the following biochemical characteristics (Table II): Table II - Biochemical characteristics of fats Fat Control 1 Fat Invention 2 Fat Witness 3 Fat Invention 4 Fat Witness 5 Amount of sulfur (%) - 0.60 0.30 0.34 0.60 Amount of active sulfur at 150 ° C (%) - 0.198 0.099 0.163 0.198 Aquatic toxicity Category E (%) 1.0 3.4 2.2 3.0 3.4 Aquatic toxicity Category F (%) 0 1.7 0.9 0.1 1.7 Biodegradability Category A (%) 93 89 91 91 94 Biodegradability Category B + C (%) 7.0 11.1 9.1 9.1 6.1 Renewable carbon (%) 50 51 51 51 54 Fat Witness 6 Fat Invention 7 Amount of active sulfur at 150 ° C (%) 0.124 0.15

These grease compositions are subjected to extreme pressure and corrosion tests (Table III). Table III - Extreme pressure performance and corrosion of greases Fat Control 1 Fat Invention 2 Fat Witness 3 Fat Invention 4 Fat Witness 5 4 Extreme Pressure balls Welding load (kg) ⁽¹⁾ 160 400 315 400 315 4 Extreme Pressure balls Last load before welding (daN) ⁽²⁾ 140 340 280 320 280 4 Extreme Pressure balls Welding load (daN) ⁽²⁾ 160 360 300 340 300 Copper corrosion ⁽³⁾ 1a 1b 1a 2c 1b Fat Witness 6 Fat Invention 7 4 Extreme Pressure balls Welding load (kg) ⁽¹⁾ 315 315 4 Extreme Pressure balls Last load before welding (daN) ⁽²⁾ 260 300 4 Extreme Pressure balls Welding load (daN) ⁽²⁾ 280 320 Copper corrosion ⁽³⁾ 1a 2c ⁽¹⁾ ASTM D2596
⁽²⁾ DIN 51350/4
⁽³⁾ 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 the control grease composition 5 has a low weld load of 315 kg (ASTM D2596) or 300 daN (DIN 51350/4). The presence of a 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 solder 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 because the amount of active sulfur at 150 ° C is too low.

The presence of 4% of sulfur ester 2 and of 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).

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

The results of control grease 6 show that the combination of a sulfur fatty acid ester 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 fat according to the invention 7 shows that a combination of a sulfur fatty acid ester and PTFE in a fat composition, the amount of active sulfur at 150 ° C. according to standard ASTM D1662 provided by the ester d sulfur fatty acid being greater than or equal to 0.15%, improves the extreme pressure properties.

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

These results demonstrate that obtaining high extreme pressure performance is due to the presence of the fluoropolymer in association with a sulfur fatty acid ester which provides in the fat composition an amount of active sulfur at 150 ° C. greater than or equal at 0.15% by mass, relative to the total mass of fat composition. These extreme pressure performances go hand in hand with a low corrosion of the grease and a grease which is biodegradable, non-accumulative, non-toxic, and obtained from renewable raw materials.

Claims (15)

1. Grease composition comprising from 50 to 95% by mass, with respect to the total mass of the composition, of at least one base oil of the polyol ester type, from 1 to 20 % by mass, with respect to the total mass of the composition, of at least one fatty-acid metal soap, from 1 to 10% by mass, with respect to the total mass of the composition, of at least one fluorine-containing polymer and from 0.5 to 5% by mass, with respect to the total mass of the composition, of 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 grease composition, being greater than or equal to 0.15%.
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 60 to 90% by mass, with respect to the total mass of grease composition, of a base oil of the polyol ester type, preferably from 70 to 80%.
4. Composition according to claim 1, 2 or 3, in which the fluorine-containing polymer is polytetrafluoroethylene.
5. Composition according to any one of claims 1 to 4, comprising from 2 to 8% by mass of fluorine-containing polymer, with respect to the total mass of grease composition, preferably from 3 to 5%.
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.
7. Composition according to any one of claims 1 to 6, comprising from 1 to 4% by mass of sulfurized fatty acid ester, with respect to the total mass of grease composition, preferably from 2 to 3%.
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-hydroxystearate.
10. Composition according to any one of claims 1 to 9, comprising from 2 to 15% by mass, with respect to the total mass of the grease composition, of fatty-acid metal soap, preferably from 4 to 12%.
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 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.
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 0.18% by mass, preferably greater than or equal to 0.20%.
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.
15. 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 of 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 0.15%, with respect to the total mass of grease composition, in order to improve the extreme-pressure performance according to standards ASTM D2596 and/or DIN 51350/4 of the grease composition.