GEARBOX LUBRICANT COMPOSITION

Description

[0001] The present invention relates to gear lubricating compositions. Said compositions according to the invention are biodegradable, do not exhibit bioaccumulation in organisms and do not exhibit toxicity to the environment, more particularly the aquatic environment.

[0002] Since December 2013, US regulations have been amended, requiring all ships sailing in US waters to use EAL (Environmentally Acceptable Lubricant) products, and since 1992 in Europe, an Ecolabel has been used to identify environmentally friendly lubricant products. The components of these products may be from the LuSC (Lubricant Substance Classification) list and meet strict biodegradability, bioaccumulation, and aquatic toxicity requirements. Ecolabel lubricants are considered lubricants that meet the environmental specifications of EAL lubricants.

[0003] These Ecolabel or EAL lubricants are used in equipment that may have interfaces and / or contact with a user, with air and / or with water. This applies in particular to lubricating compositions for gears that may be in direct contact with water and / or air and / or with humans and / or any other contact requiring biodegradable, non-toxic products.

[0004] Furthermore, gear lubricant compositions for industrial or marine use must meet very specific specifications in terms of performance, particularly in terms of tribological performance and seal compatibility. There is therefore an interest in providing biodegradable lubricant compositions, which do not bioaccumulate in organisms, which do not present toxicity for the environment, more particularly the aquatic environment and which meet all the tests specific to gear lubricant compositions.

[0005] An objective of the present invention is to provide a lubricating composition, in particular for gears, which is biodegradable, does not exhibit bioaccumulations in organisms and does not exhibit toxicity to the environment, more particularly the aquatic environment.

[0006] Another objective of the present invention is to provide such a composition which meets the specific properties relating to gear compositions, in particular in terms of tribological properties and joint compatibility.

[0007] Still other objectives will appear upon reading the description of the invention which follows.

[0008] EP 0 612 831 A1 relates to flame-retardant hydraulic oils, possibly usable for lubricating gears, based on synthetic esters.

[0009] The present application relates to a gear lubricating composition comprising: 97 to 99.9% by weight of a trimethylolpropane triester which is trimethylolpropane triisostearate; and 0.1 to 3% by weight of at least one additive chosen from anti-wear additives, extreme pressure additives, antioxidants, anti-corrosion additives, metal deactivator additives, anti-foams, and mixtures thereof.

[0010] In the context of the present invention, the term "lubricating composition" means a lubricating composition meeting the criteria of Regulation EEC No. 66 / 2010 of the European Parliament and of the Council of 25 November 2009. This regulation makes it possible to establish the European Union Ecolabel. The certification standard for the European Union Ecolabel for Lubricants (identification no. EC 511 revision 4 of 04 / 07 / 2016) details the criteria for Lubricants. The substances and mixtures subject to limitation or exclusion are defined in this standard. The additional requirements for aquatic toxicity are specified (OECD 201 methods for algae, OECD 202 for daphnia, OECD 203 for fish). The criteria for biodegradability and bioaccumulation potential are defined in this same standard.

[0011] Trimethylolpropane triester is trimethylolpropane isostearate.

[0012] The additives that can be used in the compositions according to the invention are additives from the LuSC-list or additives making it possible to obtain a biodegradable formula meeting the Ecolabel standard or the American EAL specifications.

[0013] Anti-wear additives and extreme pressure additives protect surfaces from friction by forming a protective film adsorbed on these surfaces. There are a wide variety of anti-wear additives. Preferably, some additives are both anti-wear and extreme pressure additives.

[0014] Preferably for the lubricating composition according to the invention, the anti-wear and extreme pressure additives are chosen from ashless phosphorus or phosphorus-sulfur additives such as, for example, phosphates, phosphorothionates, phosphonates, dithiophosphates and thiophosphates such as dialkyl dithiophosphates.

[0015] As anti-wear additives, we can also mention triaryl thiophosphate, carbamates and thiocarbamates.

[0016] Also preferably, certain additives are both anti-wear, extreme pressure and anti-corrosion additives. Among these additives, mention may be made of amine phosphates which may be used in the lubricating composition according to the invention.

[0017] Advantageously, the lubricating composition according to the invention may comprise at least one anti-corrosion additive such as an N-acyl sarcosine compound.

[0018] Advantageously, the lubricating composition according to the invention may comprise at least one metal deactivating additive such as a tolutriazole or di Mercapto Thiadiazole derivative.

[0019] Advantageously, the lubricating composition according to the invention may comprise at least one anti-foam additive such as a silicone compound or a polyacrylate compound.

[0020] Advantageously, the lubricating composition according to the invention may comprise at least one antioxidant additive.

[0021] The antioxidant additive generally helps to delay the degradation of the lubricant composition in service. Antioxidant additives act in particular as free radical inhibitors or hydroperoxide destroyers. Among the commonly used antioxidant additives, we can cite phenolic antioxidant additives and amine antioxidant additives.

[0022] The phenolic antioxidant additives may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge.

[0023] Preferably according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group of which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C 1 -C 10 alkyl group, preferably a C 1 -C 6 alkyl group, preferably a C 4 alkyl group, preferably by the tert-butyl group.

[0024] The amine antioxidant additives may be chosen from diphenylamines, diphenylamines substituted by at least one C 1 -C 12 alkyl group, N,N'-dialkyl-aryl-diamines, octylphenyl naphthylamine and mixtures thereof.

[0025] Examples of amine compounds are aromatic amines, for example aromatic amines of formula NR 4< R 5< R 6< in which R 4< represents an aliphatic group or an aromatic group, optionally substituted, R 5< represents an aromatic group, optionally substituted, R 6< represents a hydrogen atom, an alkyl group, an aryl group.

[0026] Amino antioxidant additives can be used in combination with phenolic antioxidant additives.

[0027] Preferably, the composition of the invention comprises as additives: 0.1 to 1% by weight of an amine phosphate type anti-wear additive; and 0.1 to 1% by weight of a phenolic antioxidant additive.

[0028] Preferably the amine phosphate is chosen from alkyl amine phosphates.

[0029] Preferably, the phenolic antioxidant is preferably chosen from sterically hindered phenols chosen from compounds comprising a phenol group in which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C 1 - C 10 alkyl group, preferably a C 1 - C 6 alkyl group, preferably a C 4 alkyl group, preferably by the tert-butyl group. Preferably, the phenol is chosen from phenolic compounds in which the two vicinal carbons of the carbon carrying the alcohol function are substituted by at least one C 1 - C 10 alkyl group, preferably a C 1 - C 6 alkyl group, preferably a C 4 alkyl group, preferably by the tert-butyl group, and in which another carbon is substituted by an alkyl-ester group.

[0030] Particularly advantageously, the composition according to the invention is biodegradable, does not bioaccumulate in organisms and does not present any toxicity for the environment, more particularly the aquatic environment and meets the European Ecolabel label and the American EAL specifications. Furthermore, the composition according to the invention meets the various characteristic tests for gear lubricant compositions.

[0031] The present invention also relates to the use of the lubricating composition according to the invention for the lubrication of gears, in particular in the marine field and in equipment having gears which may be in contact with the environment (water, air, etc.) or humans.

[0032] The composition according to the invention is also useful for the lubrication of equipment comprising gears, in particular for the lubrication of the stern tube.

[0033] The stern tube is the system that allows the propeller shaft to pass through the hull while maintaining maximum watertightness.

[0034] The present invention also relates to a method of lubricating gears using the lubricating composition according to the invention, that is to say comprising the lubrication of the parts in contact with a lubricating composition according to the invention.

[0035] The present invention also relates to a method for lubricating equipment comprising gears, in particular the stern tube, comprising the use of a lubricating composition according to the invention, i.e. the lubrication of the internal walls of the equipment comprising gears, in particular the internal walls of the stern tube, with a lubricating composition according to the invention.

[0036] The present invention will now be described with the aid of the following non-limiting examples. Example 1: Example of Composition according to the invention

[0037] Table 1 describes an example of a composition according to the invention. Table 1 Components Composition 1 content in % m / m Trimethylolpropane triisostearate 98,52 Phenolic antioxidant 0,5 Anti-wear amine phosphate 0,5 Dialkyl dithiophoshate anti-wear 0,09 Anti-corrosion 0,1 Metal deactivator 0,09 Silicone antifoam stock solution 0,2 Example 2: Tribological tests

[0038] The following tribological tests were carried out: FZG A / 8.3 / 90°C according to ISO 14635-1 (equivalent to CEC L-07-A-95) FZGA / 8.3 / 60°C according to modified ISO 14635-1 FZG A10 / 16.6R / 30 according to ISO 14635-2 (equivalent to CEC L-84) FZG A10 / 16.6R / 90 according to ISO 14635-2 (equivalent to CEC L-84) Micropitting C-GF / 8.3 / 90 according to FVA 54 / I-IV FAG-FE8 D7.5 / 80-80 according to DIN51819-3 FAG-FE8 D7.5 / 100-80 according to DIN51819-3

[0039] The results are shown in Table 2 below. A + means that the composition passes the standard test used to determine gear wear or seizure. A - means that the composition does not pass this test. Table 2 Measured parameter Performance to be achieved Composition 1 FZG A / 8.3 / 90°C Bearing seizure damage >12 >14 FZG A / 8.3 / 60°C Bearing seizure damage + FZG A10 / 16.6R / 30 Bearing seizure damage + FZG A10 / 16.6R / 90 Bearing seizure damage report 9 Micropitting C-GF / 8.3 / 90 according to FVA 54 / I-IV Gear wear Minimum 10 Greater than 10 FAG-FE8 D7.5 / 80-80 Wear of rolling elements Maximum 20 mg 4 mg FAG-FE8 D7.5 / 100-80 Wear of rolling elements + FZG low speed wear test at 40-60°C, Method DGMK 377-01 (C / 0.05 / 90:120 / 12) Total wear of gears +

[0040] These tests indicate that the composition according to the invention passes the tests implemented to measure wear and seizure in gears, that is to say that the composition according to the invention implemented in gears allows for minimal wear and seizure of the elements constituting the gears. Example 3: Joint compatibility

[0041] Joint tests were carried out in two ways: FKM-2 - 168h / 130°C and 168h / 175°C, Freudenberg tests according to the method described in document FB 73 11 008 “Static and dynamic oil compatibility tests for Freudenberg radial shafts seals to release the usage in Flender-gear units applications (Table T 7300)”, Ed. 2013. Table 3 Joint tests - FKM-2 - 168h / 130°C Acceptable limits in % Composition 1 Volume variation Less than 7 / 8 0.3 Hardness variation report 0.3 Breaking load variation Less than 25 -0.7 Elongation-to-break variation Less than 25 5.4 Joint tests - FKM-2 - 168h / 175°C Acceptable limits in % Composition 1 Volume variation Less than 7 / 8 -1.2 Hardness variation report 1.05 Breaking load variation Less than 25 -7.8 Elongation-to-break variation Less than 25 -2.5 Nd: not determined Freudenberg Essays Acceptable limits in % Composition 1 FKM 585 elastomer 130°C / 1000h Volume variation (%) -2 / +5 2,1 Hardness variation -5 / +5 -1,2 Breaking load variation (%) -50 / +20 12,9 Variation in elongation at break (%) -60 / +20 -13,9 NBR 902 elastomer 95°C / 1000h Volume variation (%) -2 / +5 1,8 Hardness variation -5 / +5 -3,3 Breaking load variation (%) -50 / +20 -11,1 Variation in elongation at break (%) -60 / +20 -21,1 FKM elastomer 260466 130°C / 1000h Volume variation (%) -2 / +5 0,9 Hardness variation -5 / +5 -1 Breaking load variation (%) -50 / +20 9,5 Variation in elongation at break (%) -60 / +20 5

[0042] These results show that the lubricating composition according to the invention is compatible with the different seals studied and does not deteriorate the properties of the seals.

Claims

1. Use of a composition comprising: - 97 to 99.9% by weight of a trimethylolpropane triester which is trimethylolpropane tri-isostearate; and - 0.1 to 3% by weight of at least one additive chosen from among anti-wear additives, extreme pressure additives, antioxidants, anticorrosive additives, metal deactivator additives, defoamers, and mixtures thereof, for the lubrication of gears or equipment comprising gears, in particular the stern tube.

2. Use according to claim 1, wherein the composition comprises: - 0.1 to 1% by weight of an anti-wear additive phosphate of amine; and - 0.1 to 1% by weight of a phenolic antioxidant additive.

3. Use according to claim 2 wherein the amine phosphate is selected from amine alkyl phosphate.

4. Use according to any one of claims 1 to 3, wherein the equipment comprising gearing is the stern tube.

5. Method of lubricating gearing or equipment comprising gearing, in particular the stern tube, comprising the implementation of the composition as described according to one of claims 1 to 3.