Additive composition based on at least partially re-refined lubricating oils

Abstract

The present invention relates to an additive composition, in particular intended to be incorporated into a lubricant composition or into a fuel composition, comprising: - at most 60% by weight of at least one at least partially re-refined lubricating oil, - at least 40% by weight of at least one additive chosen from the usual additives for a lubricant composition and / or for a fuel composition.

Description

[0001] COMPOSITION OF ADDITIVES BASED ON LUBRICATING OILS AT LEAST IN

[0002] RE-REFINED PARTS

[0003] The present invention relates to an additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition, said additive composition being based on an at least partly re-refined lubricating oil. The invention also relates to the use of an at least partly re-refined lubricating oil for preparing an additive composition having a low carbon footprint.

[0004] A lubricating composition is typically composed of a base oil to which several additives are generally associated, designed to boost the lubricating performance of the base oil, such as friction modifier additives, but also to provide additional performance.

[0005] Similarly, a fuel composition is typically composed of a base fuel to which are generally associated several additives dedicated to boosting the performance of the base fuel, such as combustion aids or anti-sedimentation agents, but also to provide additional performance.

[0006] In both cases, the final compositions (lubricant or fuel) are generally prepared by diluting an additive concentrate, commonly referred to as an "additive composition." In the case of lubricating compositions, the diluent consists of one or more base oils. In the case of fuel compositions, the diluent consists of one or more base fuels.

[0007] Whether the additive composition is intended to be integrated into a lubricating composition or into a fuel composition, the additive composition consists of a base oil in which one or more additives of interest are dissolved and / or diluted. An additive composition is distinguished from a lubricating composition by its high additive content, typically greater than or equal to 40% by mass, relative to the total mass of the additive composition. Conversely, a lubricating composition has a high base oil content, typically greater than 60% by mass.

[0008] Current environmental concerns, particularly with a view to reducing carbon dioxide emissions, have led to an urgent need for lubricant and / or fuel compositions with a reduced carbon footprint. However, it is essential that these compositions with a reduced carbon footprint have technical performance levels that are at least equivalent to, or even superior to, those used to date.

[0009] There is therefore a need for lubricating and fuel compositions with a reduced carbon footprint, while retaining satisfactory or even improved technical properties.

[0010] Reducing the carbon footprint of lubricant and fuel compositions involves many avenues. One of these is reducing the carbon footprint of the additive compositions used to prepare the final compositions.

[0011] There is therefore a need to have additive compositions, intended to be integrated into a lubricating composition or into a fuel composition, having a reduced carbon footprint, compared to the additive compositions of the prior art.

[0012] In particular, there is a need to have additive compositions having a reduced carbon footprint compared to the additive compositions of the prior art, and allowing the preparation of final compositions (lubricants or fuels) having equivalent, or even improved, properties compared to current compositions.

[0013] Summary of the invention

[0014] The invention firstly relates to an additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition, comprising:

[0015] - at most 60% by mass of at least one lubricating oil which is at least partly re-refined,

[0016] - at least 40% by mass of at least one additive chosen from the usual additives for lubricating compositions and / or for fuel compositions, in particular chosen from friction modifying additives, anti-wear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant (PPD) additives, dispersants, anti-foaming agents, thickeners, anti-corrosion agents, corrosion inhibitors, metal passivating agents, pH regulating additives, colorants, emulsifying agents, sequestering agents, biocidal agents, demulsifiers, reodorants, procetane additives, friction modifiers, lubricity additives or smoothness additives, combustion aids, cloud point improvers, limit temperature improvers filterability, anti-sedimentation agents,conductivity modifying agents and mixtures thereof. Preferably, the at least partly re-refined lubricating oil has one or more of the following characteristics:,

[0017] - the at least partly re-refined lubricating oil comes from a used lubricant having been subjected to one or more prior stages of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material,

[0018] - the at least partly re-refined lubricating oil has a kinematic viscosity, measured at 100°C according to standard ASTM D445, greater than or equal to 5 mm 2 / s, in particular between 5 mm 2 / s and 12 mm 2 / s, more particularly between 5 mm 2 / s and 10 mm 2 / s ;

[0019] - the at least partly re-refined lubricating oil has a viscosity index greater than or equal to 100, in particular between 100 and 130, in particular between 102 and 125;

[0020] - the at least partly re-refined lubricating oil has a Noack volatility of less than or equal to 15%, in particular between 8% and 15%, preferably strictly less than 13.5%, and more particularly between 8% and 13.2%;

[0021] - the at least partly re-refined lubricating oil has a sulphur content of between 0.02% and 0.3% by mass, relative to the total mass of said partly re-refined lubricating oil;

[0022] - the at least partly re-refined lubricating oil has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said partly re-refined lubricating oil,

[0023] - the at least partly re-refined lubricating oil has a density less than or equal to 880 kg / m 3 , notably between 830 and 880 kg / m 3 , in particular less than or equal to 875 kg / m 3 , and more particularly between 840 and 875 kg / m 3 .

[0024] - the at least partly re-refined lubricating oil has a thermal conductivity, measured at 100°C and at atmospheric pressure, greater than or equal to 125 mW / mK, in particular between 125 and 145 mW / mK, in particular greater than or equal to 128 mW / mK and more particularly between 128 and 140 mW / mK.

[0025] According to one embodiment, the additive composition according to the invention further comprises one or more base oils distinct from the re-refined lubricating oil, in particular chosen from virgin base oils.

[0026] Preferably, said at least one additive is chosen from antioxidants, pour point depressants (PPD), viscosity index (VI) improvers, antioxidants and mixtures thereof, preferably from pour point depressants (PPD), viscosity index (VI) improvers and mixtures thereof.

[0027] The invention also relates to the use of an at least partly re-refined lubricating oil, in particular as defined above and in detail below, as a solution fluid, in particular as a base oil, in an additive composition.

[0028] In particular, the subject of the invention is the use of an at least partly re-refined lubricating oil, in particular as defined above and in detail below, to reduce the carbon footprint of said additive composition, compared to the same additive composition prepared from a virgin base oil.

[0029] The invention also relates to a process for preparing a lubricating composition, said process comprising diluting an additive composition as defined above and described in detail below in a lubricating oil, optionally at least partly re-refined.

[0030] The invention finally relates to a process for preparing a fuel composition, said process comprising diluting an additive composition as defined above and described in detail below in a fuel.

[0031] The inventors have surprisingly discovered that it is possible to formulate an additive composition, intended to be integrated into a lubricating or fuel composition, from re-refined oils from used oil recycling channels.

[0032] In particular, the inventors have discovered that it is possible to prepare compositions based on re-refined oils and having a high content of additives, typically greater than or equal to 40% by mass, relative to the total mass of the composition.

[0033] More particularly, the inventors discovered that the re-refined oils had a solvent power high enough to allow the dissolution therein of a significant quantity of usual additives, and in particular sufficiently high to allow the preparation of additive compositions based on re-refined oils.

[0034] For the purposes of the invention, the term "solvent power" means the capacity of a substance, in particular an oil, to form a homogeneous solution with other substances, in particular with usual additives for lubricants or fuels.

[0035] As explained in detail below, the composition of re-refined oils differs from that of virgin base oils, in particular by the presence of degradation products. It was therefore not obvious to the inventors that these re-refined oils could be used for the preparation of concentrated compositions, in particular for the preparation of additive compositions. In particular, it was not obvious according to them that at least partly re-refined oils could have a sufficiently high solvent power to allow the preparation of additive-concentrated compositions.

[0036] The additive compositions of the invention are thus advantageous in that they have a reduced carbon footprint, compared to virgin oil-based additive compositions, in that they are prepared from recycled oils, in particular re-refined oils.

[0037] The inventors have also discovered that, unexpectedly, re-refined oils have improved, in particular increased, solvent power compared to virgin base oils. Thus, it is possible to prepare, from re-refined oils, additive compositions having a higher additive content, compared to additive compositions prepared from the same additives but from a virgin base oil.

[0038] This increased solvent power thus allows the preparation of more concentrated additive compositions, and therefore less voluminous with a constant quantity of additives. The additive compositions according to the invention are thus advantageous in that they allow transport costs to be reduced, as well as the associated carbon footprint.

[0039] Detailed description of the invention

[0040] The invention firstly relates to an additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition, comprising:

[0041] - at least one lubricating oil at least partly re-refined,

[0042] - at least one additive.

[0043] At least partially re-refined lubricating oil

[0044] For the purposes of the invention, the term "at least partly re-refined lubricating oil", also known as "at least partly regenerated oil" or "at least partly recycled oil" means a lubricating oil derived from a used lubricating composition having been subjected to one or more re-refining treatment steps.

[0045] It is understood that a used lubricating composition may be a mixture of several used lubricating compositions, from the same source or from several different sources.

[0046] According to one embodiment, a re-refined lubricating oil according to the present invention comprises one or more alkylphenol(s). By "alkylphenol" is meant a phenolic compound with an alkyl group Ri in the para position, and therefore of formula Ri- C6H4-OH. The presence of alkylphenol is characteristic of re-refined lubricating oils, since native (unused) oils do not comprise alkylphenol.

[0047] Preferably, the content of alkylphenol(s) in the re-refined lubricating oil according to the present invention is from 5 to 3,200 ppm.

[0048] A re-refined lubricating oil according to the present invention may for example comprise from 10 to 2000 ppm, preferably from 15 to 1500 ppm, of alkylphenol(s).

[0049] According to one embodiment, a re-refined lubricating oil according to the present invention comprises from 10 to 300 ppm, preferably from 15 to 250 ppm, of alkylphenol(s).

[0050] According to one embodiment, a re-refined lubricating oil according to the present invention comprises from 150 to 2,000 ppm, preferably from 200 to 1,500 ppm, of alkylphenol(s).

[0051] The alkylphenol(s) content in the re-refined lubricating oil is measured according to the method described in the patent application filed under number FR 23 15133.

[0052] This method is based on the implementation of liquid chromatography and mass spectrometry steps, using a standard compound which is 4-hexadecylphenol.

[0053] For the liquid chromatography steps, a particle-filled column composed of C8-bonded silica is used. Measurements are carried out at 40°C with a flow rate of 0.4 mL / min.

[0054] Here, a so-called reversed-phase column is used to separate the different components of the sample (here, re-refined lubricating oil to be analyzed) according to their polarity. The composition of the mobile phase is used to modify these interactions over time and thus gradually elute the different molecules of the sample analyzed (here, re-refined lubricating oil).

[0055] The mobile phase is used in the form of a gradient as shown in the table below, from a solution A comprising 50% water and 50% acetonitrile and a solution B comprising 100% methanol.

[0056] Using mass spectrometry detection, it is then possible to obtain the signal produced only by the molecules of interest, identified both by their mass and their retention time. The ionization source used is preferably the electrospray ionization (ESI) source which allows the selective ionization of polar compounds. In the case of the method used here, the detection mode chosen is the negative detection mode because it allows the selective ionization of polar compounds with an acidic character. The range for masses (m / z) varies from 100 to 1200.

[0057] In particular, the method for measuring the alkylphenol content in the re-refined lubricating oil used according to the invention comprises a first step consisting of preparing the standard solution (4-hexadecylphenol) and the solution to be analyzed (re-refined lubricating oil): preparing a standard solution at different concentrations to obtain a calibration line as explained later, by dilution in THF with the addition of 2% ammonium hydroxide; and preparing a solution of said re-refined lubricating oil by dilution in THF with the addition of 3% ammonium hydroxide.

[0058] To establish the calibration curve, the intensity of the chromatographic peak associated with the 4-hexadecylphenol ion of the standard is recovered by plotting an extracted ion chromatogram (EIC). This makes it possible to have a chromatogram extracted only for a given m / z, namely here 317.28 for the standard molecule, the deprotonated form corresponding to the ion [C22H38O-H]". The intensity of the EIC is therefore recovered for each of the analyses at the different concentrations tested.

[0059] The data obtained allow the construction of the calibration line. This calibration line is obtained by injecting several standard solutions at different concentrations: the line is constructed by linear regression, and the calculation of the correlation coefficient (R 2 ) allows to check the linearity of the detector and the correct preparation of the standard solutions.

[0060] The associated equation then allows us to predict the concentration of an unknown sample by entering the experimentally obtained y value. Here, the equation is: y = 1001.9x - 15309

[0061] To quantify the alkylphenols in the re-refined lubricating oil according to the invention, the analysis method comprises a step of identifying the m / z of the alkylphenol residues on the average mass spectrum by integrating the entire chromatogram. This average spectrum corresponds to an average of all the mass spectra obtained on the complete chromatographic run. This makes it possible to have all the compounds that were ionized during the analysis. From this average mass spectrum is extracted a mass list grouping together all the m / z ratios of the ions with the associated intensities.

[0062] The next step is to construct a Kendrick diagram with this mass list. This is a molecular map that allows us to identify series of compounds of the same type, but with different degrees of alkylation, by overcoming the mass defect of the hydrogens in the CH2 motif.

[0063] The Kendrick diagram can be made by calculating the following values: 14.00000

[0064] KM = mass (IUPAC or EXPER) x - — v J 14.01565 where KM corresponds to the Kendrick mass, IUPAC mass corresponds to the theoretical mass calculated from the sum of each element constituting the molecule of interest, here for the standard molecule hexadecylphenol of formula C22H37O-, the IUPAC mass = 317.284440 g. mol -1 , and EXPER mass corresponds to an experimental mass measurement, measured during an experiment.

[0065] The Kendrick mass KM is calculated for each peak of the average mass spectrum, determined previously as explained above.

[0066] Then, the Kendrick MKD mass defect is typically calculated according to the following equation:

[0067] KMD = NKM - KM where KMD corresponds to the Kendrick mass defect,

[0068] KM corresponds to the Kendrick mass, and

[0069] NKM is the nearest integer rounding of the Kendrick mass KM.

[0070] The Kendrick KMD mass defect is calculated for each peak (each peak corresponding for example to a compound present in the re-refined lubricating oil).

[0071] Kendrick diagrams are a 2D molecular map representing KMDs versus NKMs. Homologous compounds varying in their degree of alkylation appear as a horizontal line.

[0072] The set of m / z of the alkylphenols is obtained by applying a filter on the y-axis (KMD): this is the value KMD = 0.069. Once all the m / z at KMD = 0.069 are identified, they are used to construct extracted ion chromatograms (EIC) as described for the standard molecule. This allows to have a chromatogram dependent only on the requested m / z. The intensities of the EIC of each m / z corresponding to the alkylphenols are thus summed to have the total intensity (several alkylphenol type molecules are obtained on the spectra of re-refined lubricating oil according to the invention, these molecules varying by the length of their alkyl chain).

[0073] To obtain a quantification, the sum of the intensities of the obtained EICs is used as the value of y for the equation of the calibration line. For example, if the obtained value is 2.45 E6, the quantification of alkylphenol residues in the re-refined lubricating oil used according to the invention is: y = 1001.9% - 15309

[0074] > y + 15309

[0075] X ~ 1001.9 and therefore x is equal to 2460.6 ppm.

[0076] According to one embodiment, a re-refined lubricating oil according to the present invention comprises one or more polyalphaolefins (PAOs). The presence of polyalphaolefin(s) is characteristic of re-refined lubricating oils, since native (unused) oils do not comprise polyalphaolefins (PAOs).

[0077] Figures 1 and 2 represent two-dimensional chromatograms of two re-refined lubricating oils according to the present invention. The arrow in each of the figures indicates the characteristic peak of PAO (at C30), a marker of re-refined oils.

[0078] According to one embodiment, a re-refined lubricating oil according to the present invention comprises one or more polyalphaolefins (PAOs) comprising less than 40 carbon atoms, and preferably comprising 30 carbon atoms.

[0079] The presence of PAOs in re-refined lubricating oil is determined according to the method described in the patent application filed under number FR 24 06231.

[0080] This method is based on the implementation of comprehensive two-dimensional gas chromatography (GCxGC) and classification steps.

[0081] In particular, it is implemented via a chromatography device (12), the chromatography device comprising a comprehensive two-dimensional gas chromatography module comprising a first column A and a second column B, and capable of separating different compounds of the product according to their volatility and their polarity, the chromatography device further comprising a flame ionization detector capable of measuring an intensity of electric ionization current generated for each compound included in the product, the chromatography device being calibrated with at least one calibration product, making it possible to correct the retention time of the different compounds present in the product; The method is furthermore implemented by an electronic classification device, comprising the following steps: a.determining a table describing the intensity of the ionization electric current generated for each compound included in the product as a function of the corrected retention times in columns A and B, from a measurement carried out by the chromatography device on the product; b. assigning a class to the product, from among a plurality of classes, by applying a multivariate statistical algorithm to the table, said algorithm being trained on tables obtained from reference products.

[0082] The chromatography device comprises a comprehensive two-dimensional gas chromatography module comprising a first column A and a second column B. The comprehensive two-dimensional gas chromatography modules (2DGC or GCxGC) that can be used in the context of the present disclosure are those described in the literature.

[0083] These modules generally include an injection module, a vaporization module, a first column A, a modulator, and a second column B. They allow a two-dimensional separation of complex mixtures, because the product is subjected to two separations, we then obtain a two-dimensional chromatogram as a function of the retention times of columns A and B and a table describing the intensity of the electric ionization current generated for each compound included in the product as a function of the corrected retention times in columns A and B.

[0084] According to one embodiment, the first column A and the second column B are columns based on polydimethylsiloxane partially functionalized with phenyl groups. The percentage of phenyl group functionalization can be between 2 and 50%. According to a particular embodiment, the percentage of phenyl group functionalization of column A is greater than the percentage of phenyl group functionalization of column B. Advantageously, the length of column A is greater than that of column B. The diameter of the two columns A and B can be equivalent. The two columns can have a film thickness of 0.1 μm suitable for the separation of low-volatile samples. According to one embodiment, the temperature gradient applied to the oven is 2°C / min up to 400°C.

[0085] A quantity of product is injected into the first column A to obtain a first separation, then via the modulator, into the second column B to obtain a second separation. The product can be injected directly without pretreatment, particularly in the case of lubricating oil analysis. The GCxGC device is coupled to a flame ionization detector, or Fl D. This is capable of measuring the intensity of the electric ionization current generated for each compound included in the product. The flame ionization detector is located at the outlet of the second column.

[0086] Following analysis by the flame ionization detector, a table describing the intensity of the ionization electric current generated for each compound included in the product, as a function of the corrected retention times in columns A and B, is determined. The table is therefore derived from a two-dimensional chromatogram obtained from a measurement carried out by the chromatography device on the product.

[0087] In addition, during this initial step, an external calibration is performed to correct the retention time of the various compounds present in the product. This is performed by injecting at least one calibration product. In the case where the product to be classified is a lubricating oil, the calibration product may be a lubricating oil, preferably recycled. According to one embodiment, the calibration product comprises at least one marker, preferably at least two markers. The marker may be selected from n-paraffins, polyalphaolefins, and their mixture. The correction of the retention times may be performed by software.

[0088] At the end of this initial step, the classification device moves on to a next step, during which it assigns, via its product assignment module, a respective class from among the plurality of classes, by applying a multivariate statistical algorithm to the table, said algorithm being trained on tables obtained from reference products.

[0089] The multivariate statistical algorithm used in the allocation step may be a partial least squares regression multivariate statistical algorithm; the multivariate statistical algorithm preferably being selected from the group consisting of: a partial least squares regression algorithm, and a partial least squares regression algorithm with discriminant analysis. The algorithm is typically a partial least squares regression algorithm, such as the PLS algorithm or the PLS-DA algorithm.

[0090] The multivariate statistical algorithm used during the attribution step is trained on tables obtained from reference products.

[0091] In Partial Least Squares Discriminant Analysis (PLS-DA), the prediction coefficient on a scale of 0 to 1 represents the probability or confidence that a sample belongs to a particular class. Here is how this coefficient is calculated and used:

[0092] 1. Creation of latent variables:

[0093] PLS-DA creates latent variables (components) that capture the maximum variance of the X data (the predictors) while maximizing the covariance with the Y classes (the categorical responses).

[0094] 2. Calculation of scores:

[0095] Samples are projected onto these latent variables, producing scores that are used to discriminate between classes.

[0096] 3. Modeling:

[0097] A linear model is fitted to these scores to predict the values ​​of Y. In the case of PLS-DA, Y is often binary encoded to represent classes (e.g., 0 for group A and 1 for group B).

[0098] 4. Prediction:

[0099] When predicting for new samples, the scores of these samples are calculated and passed through the linear model to obtain a continuous prediction. This continuous prediction is then transformed into a probability on a scale of 0 to 1.

[0100] 5. Interpretation of probabilities:

[0101] These probabilities are then interpreted to assign the samples to the different classes.

[0102] For example :

[0103] - If the probability is less than 0.4, the sample is classified in group A (here group of re-refined base oils); and

[0104] - If the probability is greater than or equal to 0.4, the sample is classified in group B (conventional base oil group).

[0105] Used lubricating compositions and, consequently, regenerated base oils, comprise, in the majority quantity, one or more base oils conventionally used in the field of lubricants, such as mineral, synthetic or natural, animal or vegetable oils or their mixtures.

[0106] It can be a mixture of several base oils, for example a mixture of two, three, or four base oils.

[0107] These base oils may be of natural origin, for example from plants or animals, such as vegetable, animal, fish oils, and mixtures thereof. Examples of such oils are rapeseed oil, canola oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, animal fats, and mixtures thereof.

[0108] Advantageously, these base oils are oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in the following table, or their mixtures.

[0109] [Table 1]

[0110] In particular, the used lubricating composition, from which the regenerated lubricating oil used according to the invention is derived, may comprise at least 50% by weight of base oil(s) relative to its total weight, in particular at least 60% by weight of base oil(s), and more particularly from 60% to 99% by weight of base oil(s).

[0111] The re-refined lubricating oils used according to the invention advantageously have characteristics in terms of content of saturated compounds, sulfur content and viscosity index, satisfying the criteria defined by the API classification for oils of groups I, II, III, IV and / or V, in particular for oils of groups I, II, III and / or IV.

[0112] According to a particular embodiment, the re-refined lubricating oil used according to the invention may come from the treatment of a used lubricating composition having been used for the lubrication of a motorization system, in particular “mobile”, that is to say including light vehicles, heavy goods vehicles, so-called “off-road” mobile machines, or even marine vehicles.

[0113] According to another particular embodiment, the re-refined lubricating oil used according to the invention may come from the treatment of a used lubricating composition having been used for the lubrication of a so-called industrial system, in particular “stationary”, that is to say including, in a non-limiting manner, turbines, compressors, hydraulic systems, gears, or even forming or cutting machines.

[0114] A used lubricating composition, from which the reclaimed lubricating oil used according to the invention is derived, may contain various conventional additives in the field of lubricants, such as friction modifier additives, extreme pressure additives, anti-wear additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant (PPD) additives, dispersing agents, anti-foaming agents, thickeners, and mixtures thereof.

[0115] As already mentioned above, the properties of the used lubricating composition are degraded due to its use, for a more or less long period, for the lubrication and / or cooling of a mechanical system, in particular a motorization system, such as a combustion engine.

[0116] Due to their origin, used lubricating compositions may thus contain one or more additives described above and impurities resulting from the degradation of additives originally present in the lubricant, or resulting from the wear of moving mechanical parts.

[0117] The composition of used lubricant can of course vary depending on the origin of the lubricant, its initial formulation and the fact that it may have been contaminated differently depending on its use.

[0118] The regenerated lubricating oil used according to the invention comes more particularly from a used lubricating composition having been subjected to one or more prior pre-treatment steps known in the field of re-refining used lubricants.

[0119] In particular, these treatment steps aim to remove, at least partially, water, solid particles, fuel and / or other contaminants, such as polycyclic aromatic hydrocarbons (PAHs), which are undesirable in the formulation of lubricants.

[0120] According to a particular embodiment, the regenerated lubricating oil used according to the invention comes from a used lubricant having been subjected to one or more prior steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material, preferably as detailed below.

[0121] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one dehydration step. This dehydration step makes it possible to eliminate any water possibly present in the used lubricant.

[0122] Advantageously, the regenerated lubricating oil used according to the invention thus comprises a water content of less than or equal to 10% by mass, in particular less than or equal to 5% by mass, in particular less than or equal to 2% by mass and more particularly less than or equal to 1% by mass, relative to the total mass of said regenerated lubricating oil.

[0123] This dehydration can be carried out by any method known to those skilled in the art, for example by distillation, evaporation, decantation, heating or passing a flow of hot air over the used lubricating composition.

[0124] According to one embodiment, the dehydration step can be carried out at a temperature between 50°C and 250°C, preferably between 100°C and 200°C. In particular, it can be carried out at a pressure between 50,000 and 150,000 Pa, preferably at atmospheric pressure.

[0125] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one prior filtration step. This filtration can be carried out by any method known to those skilled in the art. This filtration step can be a particulate or non-particulate filtration step. It can, for example, be carried out by diatomaceous earth type systems.

[0126] Preferably, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one distillation step, preferably following a prior dehydration step. Said distillation step(s) may be carried out by any technique known to those skilled in the art. It may be, for example, atmospheric distillation or distillation under reduced pressure. The distillations may, for example, be carried out at a temperature of between 100°C and 500°C, preferably between 200°C and 400°C, more preferably between 300°C and 380°C. In particular, they may be carried out at a pressure of between 25 and 2,000 Pa, preferably between 50 and 1,000 Pa, more particularly between 50 and 250 Pa.

[0127] Advantageously, the regenerated lubricating oil used according to the invention is obtained by subjecting a used lubricating composition to at least one prior step of passing said used lubricating composition over an adsorbent material.

[0128] The adsorbent material advantageously allows the selective adsorption of aromatic compounds, in particular PAHs.

[0129] In particular, passing over an adsorbent material, preferably over activated carbon, advantageously makes it possible to reduce the content of polycyclic aromatic hydrocarbons (PAHs), notably chosen from chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, dibenz[a,h]anthracene and / or benz[a]anthracene, of the used lubricating composition.

[0130] The term "passage of the used lubricating composition over an adsorbent material" means the flow of the used lubricating composition over the adsorbent support.

[0131] The adsorbent materials can be, for example, activated carbon, zeolites, clays or functionalized porous compounds. Preferably, it is activated carbon.

[0132] For example, the regenerated lubricating oil of the invention can be obtained from the treatment of a used lubricating composition according to the method described in document WO 2018 / 109208.

[0133] In the case of passing the used lubricating composition over activated carbon, the quantity of activated carbon used is preferably between 0.5 and 60 g of activated carbon per liter of used lubricating composition, preferably between 0.5 and 50 g / L, preferably from 1 to 50 g / L, preferably between 1 and 30 g / L, for example between 5 and 60 g / L, preferably between 5 and 50 g / L.

[0134] The flow rate of the used lubricating composition can be between 1 m 3 / h and 15 m 3 / h, for example between 5 and 10 m 3 / h.

[0135] Preferably, the activated carbon is characterized by a density between 200 and 500 kg / m 3 , for example measured according to ASTDM D2854.

[0136] Preferably, the activated carbon is a coal, preferably comprising from 70 to 95%, advantageously from 80 to 90% by weight of carbon.

[0137] The step of passing the used lubricating composition onto an adsorbent support, preferably onto activated carbon, is advantageously preceded by the following preliminary steps:

[0138] - one or more distillation stages; and - a filtration stage, in particular as defined above.

[0139] Advantageously, the regenerated lubricating oil used according to the invention can be obtained by subjecting a used lubricating composition to at least one prior hydrogenation (or hydrotreatment) step, preferably which follows a prior dehydration and / or distillation step. Said hydrogenation step(s) can be carried out by any technique known to those skilled in the art and generally consist of treating the lubricating oil with hydrogen, generally in the presence of a hydrotreatment catalyst. Such a catalyst can contain, for example, at least one oxide or sulfide of at least one group VI metal and / or at least one group VIII metal, such as molybdenum, tungsten, nickel or cobalt, and a support, for example alumina, silica-alumina or a zeolite.

[0140] Advantageously, the regenerated lubricating oil of the invention can be obtained by subjecting a used lubricating composition to at least one prior step of liquid / liquid extraction by a solvent, preferably following a prior step of dehydration and / or distillation. In particular, the liquid / liquid extraction by a solvent advantageously makes it possible to lighten a dark-colored used oil, to eliminate at least in part the bad odor or the aromatic compounds, in particular the PAHs. Said extraction step(s) can be implemented by any technique known to those skilled in the art. The extraction is generally carried out in a mixer-settler or in an extraction column, using a suitable extraction solvent.

[0141] Advantageously, the regenerated lubricating oil of the invention can be obtained by subjecting a used lubricating composition to at least one prior decantation step. Said decantation step(s) can be carried out by any technique known to those skilled in the art.

[0142] It is understood that the invention is in no way limited to the use of regenerated oils obtained according to the treatment methods described above. Other lubricating oils at least partly re-refined, for example group I and / or II, resulting from treatment steps different from those described above, may be suitable for the invention.

[0143] In any event, a re-refined lubricating oil used according to the invention is distinguished from a used lubricating oil, in particular due to the reduced content of certain undesirable contaminating elements, for example water, fuel, metallic elements or even certain heteroatoms.

[0144] A regenerated lubricating oil used according to the invention is notably characterized by a silicon content of between 0 ppm and 300 ppm, notably between 1 and 300 ppm.

[0145] A regenerated lubricating oil used according to the invention is in particular characterized by a phosphorus content of less than or equal to 100 ppm, in particular between 0 ppm and 100 ppm, for example 0 ppm.

[0146] A regenerated lubricating oil used according to the invention may also be characterized by its content of one or more other elements chosen from chlorine, oxygen and nitrogen. It may, for example, have a chlorine content of between 0 ppm and 50 ppm, for example 0 ppm.

[0147] The content of these elements can be assessed by any method known to those skilled in the art, for example by X-ray fluorescence (XRF), or by infrared or ultraviolet spectroscopy.

[0148] On the other hand, a regenerated lubricating oil used according to the invention is distinguished, due to its formation from a used lubricant, from a virgin or new base oil, oil directly derived from petroleum refining, or even from native base oils, for example of natural origin, both in terms of its composition and its physicochemical properties.

[0149] In particular, as previously indicated, surprisingly, a reclaimed lubricating oil exhibits excellent thermo-physical and hydraulic properties, particularly in terms of viscosity index, density, Noack volatility, flash point and / or thermal conductivity, and advantageously thermo-physical and hydraulic properties superior to those of a virgin base oil.

[0150] Preferably, the regenerated lubricating oil used according to the invention has a kinematic viscosity measured at 100°C according to the ASTM D445 standard of between 2 and 12 mm2 / s-1, in particular between 3 and 10 mm2 / s-1.

[0151] Preferably, the kinematic viscosity measured at 100°C according to ASTM D445 of the at least partly re-refined lubricating oil is greater than or equal to 5 mm 2 / s, for example between 5 and 12 mm 2 / s, more particularly between 5 and 10 mm 2 / s.

[0152] Advantageously, the regenerated lubricating oil used according to the invention has a kinematic viscosity measured at 40°C according to standard ASTM D445 of between 20 and 40 mm 2 / s, especially between 25 and 35 mm 2 / s. Preferably, a regenerated lubricating oil used according to the invention has a viscosity index greater than or equal to 100. The viscosity index of the at least partly re-refined lubricating oil can thus be between 100 and 130, in particular between 102 and 125.

[0153] The viscosity index can in particular be determined according to standard NF ISO 2909.

[0154] A regenerated lubricating oil used according to the invention has a Noack volatility of less than or equal to 15%.

[0155] The Noack volatility of at least partially re-refined lubricating oil can thus be between 8% and 15%.

[0156] More preferably, a regenerated lubricating oil used according to the invention has a Noack volatility strictly less than 14%. The Noack volatility of the at least partially re-refined lubricating oil can thus be between 8% and 13.5%.

[0157] Preferably, the regenerated lubricating oil used according to the invention has a Noack volatility of from 2.5% to 14%, for example from 3% to 14%, preferably from 4% to 13.5%, and preferentially from 8% to 13.2%.

[0158] Noack volatility can be determined in particular according to the CEC L-40-93 standard.

[0159] Preferably, a regenerated lubricating oil used according to the invention has a sulfur content of between 0.02% and 0.3% by mass, relative to the total mass of said regenerated lubricating oil.

[0160] According to one embodiment, the regenerated lubricating oil used according to the invention has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said regenerated lubricating oil.

[0161] The contents of these different elements can be determined according to any method known to those skilled in the art, for example by X-ray fluorescence (XRF) or by infrared or ultraviolet spectroscopy. The re-refined lubricating oil used according to the invention advantageously has at least one, at least two, at least three, or even all of the following characteristics:

[0162] - a kinematic viscosity measured at 100°C according to ASTM D445 standard greater than or equal to 5 mm 2 / s, for example between 5 and 12 mm 2 / s, more particularly between 5 and 10 mm 2 / s ;

[0163] - a viscosity index greater than or equal to 100, in particular between 100 and 130, in particular between 102 and 125;

[0164] - a Noack volatility less than or equal to 15%, in particular between 8% and 15%, preferably strictly less than 13.5%, more particularly between 8% and 13.5%;

[0165] - a sulfur content of between 0.01% and 0.3% by mass, in particular between 0.02% and 0.2% by mass, relative to the total mass of said regenerated lubricating oil;

[0166] - a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said regenerated lubricating oil.

[0167] Advantageously, a regenerated lubricating oil used according to the invention has a density less than or equal to 880 kg / m 3 , in particular less than or equal to 875 kg / m 3 The density of the at least partly re-refined lubricating oil can thus be between 830 and 880 kg / m 3 , particularly between 840 and 875 kg / m 3 .

[0168] The density can in particular be determined according to standard NF EN ISO 12185.

[0169] Advantageously, a regenerated lubricating oil used according to the invention has a flash point greater than or equal to 220°C, in particular greater than or equal to 222°C. The flash point of the at least partly re-refined lubricating oil can thus be between 220°C and 245°C.

[0170] The flash point can in particular be determined according to standard NF EN ISO 2592.

[0171] Preferably, the at least partly re-refined base oil represents at most 60% by mass of the total mass of the additive composition according to the invention, more preferably less than 50% by mass, even more preferably less than 40% by mass, advantageously less than 30% by mass, more advantageously less than 20% by mass, typically less than 10% by mass.

[0172] Preferably, the at least partly re-refined base oil represents more than 0.1% by mass of the total mass of the additive composition according to the invention, more preferably more than 0.5% by mass, even more preferably more than 1% by mass, more advantageously more than 5% by mass.

[0173] Advantageously, the at least partly re-refined base oil represents from 0.1% to 60% by mass of the total mass of the additive composition of the invention, preferably from 0.5% to 50% by mass, more preferably from 1% to 40% by mass, advantageously from 5% to 30% by mass, more advantageously from 5% to 20% by mass, typically from 5% to 10% by mass.

[0174] Additional base oils (optional)

[0175] According to one embodiment, the additive composition according to the invention further comprises one or more base oils distinct from said at least one at least partially re-refined lubricating oil.

[0176] Preferably, according to this embodiment, the additive composition according to the invention further comprises one or more new (or native or virgin) base oils.

[0177] These new base oils are in particular chosen from base oils conventionally used in the field of lubricants, such as mineral, synthetic or natural, animal or vegetable oils or their mixtures.

[0178] Advantageously, these new base oils are oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in table 1 above, or their mixtures.

[0179] An additive composition used according to the invention may thus comprise a mixture of one or more at least partly re-refined lubricating oils, in particular as described above, and one or more new base oils, for example at least one mineral oil.

[0180] More particularly, according to this embodiment, the additive composition according to the invention comprises a mixture comprising:

[0181] - at least one lubricating oil at least partly re-refined, and

[0182] - at least one new base oil (or native or virgin), in particular at least one mineral oil. Preferably, according to this embodiment, the new base oil(s) and the at least partly re-refined lubricating oil(s) together represent at most 60% by mass of the total mass of the additive composition according to the invention, more preferably less than 50% by mass, even more preferably less than 40% by mass, advantageously less than 30% by mass, more advantageously less than 20% by mass, typically less than 10% by mass.

[0183] More preferably, according to this embodiment, the new base oil(s) and the lubricating oil(s) together represent more than 0.1% by mass of the total mass of the additive composition according to the invention, more preferably more than 0.5% by mass, even more preferably more than 1% by mass, more advantageously more than 5% by mass.

[0184] Advantageously, according to this embodiment, the new base oil(s) and the lubricating oil(s) together represent from 0.1% to 60% by mass of the total mass of the additive composition of the invention, preferably from 0.5% to 50% by mass, more preferably from 1% to 40% by mass, advantageously from 5% to 30% by mass, more advantageously from 5% to 20% by mass, typically from 5% to 10% by mass.

[0185] In particular, an additive composition according to the invention may comprise from 0% to 60% by mass, in particular from 0.01% to 50% by mass of new base oil(s), distinct from the at least partly re-refined lubricating oil(s) required according to the invention and defined above, relative to the total mass of the composition.

[0186] According to an alternative embodiment, the additive composition according to the invention is free of base oil distinct from at least partly re-refined lubricating oils. In particular, according to this embodiment, the base oil used according to the invention consists essentially, or even exclusively, of at least partly re-refined base oils.

[0187] Additives

[0188] The additive composition according to the invention further comprises at least one additive, in particular chosen from the usual additives of lubricating compositions and fuel compositions.

[0189] Preferably, the additive(s) represent(s) at least 40% by mass of the total mass of the additive composition according to the invention, more preferably at least 50% by mass, even more preferably at least 60% by mass, advantageously at least 70% by mass, more advantageously at least 80% by mass, typically at least 90% by mass. Preferably, the additive(s) represent(s) at most 99.9% by mass of the total mass of the additive composition according to the invention, more preferably at most 99.5% by mass, even more preferably at most 99% by mass, more advantageously at most 95% by mass.

[0190] Advantageously, the additive(s) represent from 40% to 99.9% by mass of the total mass of the additive composition of the invention, preferably from 50% to 99.5% by mass, more preferably from 60% to 99% by mass, advantageously from 70% to 95% by mass, more advantageously from 80% to 95% by mass, typically from 80% to 90% by mass.

[0191] According to a first embodiment, the additive composition is intended to be integrated into a lubricating composition.

[0192] Thus, the additive composition according to the invention can comprise all types of additives suitable for the intended use for the lubricant, as detailed in the rest of the text.

[0193] For example, the additive composition according to the invention may comprise all types of additives suitable for use in mobile or stationary powertrain systems, more particularly mobile, for light or heavy vehicles, or even off-road vehicles, in particular in combustion powertrain systems. Such additives are well known to those skilled in the art and may in particular be chosen from friction modifier additives, anti-wear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressants (PPD), dispersants, anti-foaming agents, thickeners, anti-corrosion agents, corrosion inhibitors, metal passivators, emulsifiers, and mixtures thereof.

[0194] The additive composition of the invention may also comprise all types of additives suitable for metalworking, in particular for any metal machining operation, for example in shaping, cutting, joining processes or any other transformation of the metal such as forming, stamping, rolling, etc.

[0195] Such additives are well known to those skilled in the art and may in particular be chosen from corrosion inhibitors, anti-foam additives, pH regulating additives, metal passivating agents, colorants, emulsifying agents, sequestering agents, biocidal agents with bactericidal and / or fungicidal action and mixtures thereof.

[0196] Advantageously, an additive composition according to the invention intended to be integrated into a lubricating composition comprises one or more additives chosen from viscosity index improvers, pour point lowering additives, anti-wear additives, antioxidants and mixtures thereof. These additives may be added to the at least partly re-refined lubricating oil used according to the invention, in an appropriate quantity, determined by a person skilled in the art. It is understood that the nature and quantity of the additives used are chosen in such a way that the advantageous properties of the composition based on said at least partly re-refined lubricating oil(s) are not or are not substantially altered by the envisaged addition.

[0197] Advantageously, the additive composition according to the invention comprises at least one friction-modifying additive. The friction-modifying additives make it possible to limit friction by forming adsorbed monolayers on the surfaces of the metals in contact with them. They may be chosen from compounds providing metallic elements and ash-free compounds. Among the compounds providing metallic elements, mention may be made of transition metal complexes such as Mo, Sb, Sn, Fe, Cu, Zn, the ligands of which may be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus atoms.The ash-free friction modifying additives are generally of organic origin and may be chosen from fatty acid esters and polyols, distinct from the monoester required according to the invention, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borate fatty epoxides, fatty amines or fatty acid glycerol esters. According to the invention, the fatty compounds comprise at least one hydrocarbon group comprising from 10 to 24 carbon atoms. In particular, the molybdenum-based compounds may be chosen from molybdenum dithiocarbamates (Mo-DTC), molybdenum dithiophosphates (Mo-DTP), and mixtures thereof.

[0198] Advantageously, an additive composition according to the invention may comprise from 0.01% to 10.0% by mass of friction modifying additives, relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0199] Preferably, an additive composition according to the invention comprises at least one anti-wear additive, one extreme pressure additive or mixtures thereof. The anti-wear additives and the extreme pressure additives are dedicated to protecting the friction surfaces by forming a protective film adsorbed on these surfaces. There is a wide variety of anti-wear additives. Particularly suitable for the lubricating compositions according to the invention are the anti-wear additives chosen from polysulfide additives, sulfur-containing olefin additives or even phospho-sulfur additives such as metal alkylthiophosphates, in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates or ZnDTP. The preferred compounds are of formula Zn((SP(S)(OR)(OR'))2, in which R and R', identical or different, independently represent an alkyl group, preferably comprising from 1 to 18 carbon atoms.

[0200] Advantageously, an additive composition according to the invention may comprise from 0.01% to 10.0% by mass of anti-wear additives and extreme pressure additives, relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0201] Advantageously, an additive composition according to the invention may comprise at least one antioxidant additive. The antioxidant additive makes it possible to delay the degradation of the lubricating composition in service. This degradation may in particular result in the formation of deposits, the presence of sludge or an increase in the viscosity of the lubricating composition. They act in particular as radical inhibitors or hydroperoxide destroyers.

[0202] Commonly used antioxidant additives include phenolic antioxidants, amine antioxidant additives, and phosphosulfur antioxidant additives. Some of these antioxidant additives, for example phosphosulfur antioxidant additives, may be ash-generating. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. The antioxidant additives may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters, and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted with at least one C1-C12 alkyl group, N,N'-dialkylaryldiamines, and mixtures thereof.

[0203] Preferably, the sterically hindered phenols are 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 C1-C10 alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably by the tert-butyl group. Amino compounds are another class of antioxidant additives that can be used, optionally in combination with the phenolic antioxidant additives. Examples of amino compounds are aromatic amines, for example aromatic amines of formula NR 5 R 6 R 7 in which R 5 represents an aliphatic group or an aromatic group, optionally substituted, R 6 represents an aromatic group, optionally substituted, R 7represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R 8 S(O) Z R 9 in which R 8 represents an alkylene group or an alkenylene group, R 9 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2. Sulphurized alkyl phenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

[0204] Advantageously, an additive composition according to the invention may comprise from 0.01% to 10.0% by mass of antioxidant additive(s), relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0205] An additive composition according to the invention may also comprise at least one detergent additive. Detergent additives generally make it possible to reduce the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products. The detergent additives that can be used in a lubricating composition according to the invention are generally known to those skilled in the art. The detergent additives may be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation may be a metal cation of an alkali or alkaline-earth metal. The detergent additives are preferably chosen from alkali metal or alkaline-earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, as well as phenate salts. The alkali and alkaline-earth metals are preferably calcium, magnesium, sodium or barium.These metal salts generally comprise the metal in a stoichiometric quantity or in excess, i.e. in a quantity greater than the stoichiometric quantity. These are then overbased detergent additives; the excess metal providing the overbased character to the detergent additive is then generally in the form of a metal salt insoluble in the base oil, for example a carbonate, a hydroxide, an oxalate, an acetate, a glutamate, preferably a carbonate.

[0206] An additive composition according to the invention may comprise from 0.01% to 10.0% by mass of detergent additive(s), relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0207] Advantageously, an additive composition according to the invention may also comprise at least one pour point depressant additive (also called a "PPD" agent for "Pour Point Depressant" in English). By slowing down the formation of paraffin crystals, the pour point depressant additives generally improve the cold behavior of the lubricating composition according to the invention. Examples of pour point depressants include polyalkyl methacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes and alkylated polystyrenes.

[0208] A lubricating composition according to the invention may comprise from 0.01% to 10.0% by mass of pour point lowering additive(s), relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0209] An additive composition according to the invention may also comprise at least one dispersing agent. Such dispersing agents ensure the maintenance in suspension and removal of insoluble solid contaminants consisting of secondary oxidation products which form when the lubricating composition is in service. They may be chosen from Mannich bases, succinimides and their derivatives, such as polyisobutylene succinic anhydride derivatives.

[0210] In particular, an additive composition according to the invention may comprise 0.01% to 10.0% by mass of pour point dispersing agent(s), relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0211] An additive composition according to the invention may also comprise at least one viscosity index (VI) improver additive. Viscosity index improvers, in particular viscosity index improving polymers, ensure good cold resistance and minimal viscosity at high temperatures. Examples of viscosity index improving polymers include hydrogenated or non-hydrogenated polymer esters, homopolymers or copolymers of styrene, butadiene and isoprene, homopolymers or copolymers of olefins, such as ethylene or propylene, polyacrylates and polymethacrylates (PMA), preferably homopolymers or copolymers of olefins, such as ethylene or propylene.

[0212] In particular, an additive composition according to the invention may comprise from 0.01% to 20.0% by mass of viscosity index improving additive(s), relative to the total weight of the additive composition, preferably from 0.1% to 15.0% by mass, or more particularly from 0.5% to 14.0% by mass.

[0213] An additive composition according to the invention may also comprise at least one anti-foam additive, for example chosen from polar polymers such as polymethylsiloxanes or polyacrylates. In particular, an additive composition according to the invention may comprise from 0.01% to 10.0% by mass of anti-foam additive(s), relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0214] An additive composition according to the invention may also comprise at least one corrosion inhibiting agent and / or at least one anti-corrosion agent.

[0215] Corrosion inhibitors can advantageously reduce or even prevent the corrosion of metal parts. The nature of the corrosion inhibitor(s) can be chosen with regard to the metal to be protected against corrosion, such as aluminum, steel, galvanized steel, yellow metals, for example copper or brass.

[0216] Inorganic corrosion inhibitors include nitrites, sulfites, silicates, borates, sodium, potassium, calcium or magnesium phosphates, alkali metal phosphates, hydroxides, molybdates, zinc, magnesium or nickel sulfates.

[0217] Among the organic corrosion inhibitors that may be mentioned are aliphatic monocarboxylic acids, in particular having from 4 to 15 carbon atoms, for example octanoic acid, aliphatic dicarboxylic acids having from 4 to 15 carbon atoms, for example decanedioic acid (sebacic acid), undecanedioic acid, dodecanedioic acid, isononanoic acid or mixtures thereof, polycarboxylic acids optionally neutralized by triethanolamine, such as 1,3,5-triazine-2,4,6-tri-(6-aminocaproic) acid, alkanoylamidocarboxylic acids, in particular isononanoylamidocaproic acid, 6-[[(4-methylphenyl)sulfonyl]amino]hexanoic acid, and mixtures thereof. Borated amides, products of the reaction of amines or amino alcohols with boric acid, can also be used.

[0218] It may also include at least one anti-corrosion agent, for example compounds such as succinic polyisobutene anhydrides or thiadiazole sulfonates.

[0219] The corrosion inhibiting agents and / or the anti-corrosion agents are typically present in an additive composition according to the invention at contents of between 0.01% and 10.0% by mass, relative to the total weight of the additive composition, preferably from 0.1% to 5.0% by mass, or more particularly from 0.5% to 3.0% by mass.

[0220] The additive composition according to the invention may also comprise at least one pH regulating additive, in particular an alkaline buffer. The pH regulator makes it possible to maintain the desired pH of the lubricating composition, in particular in order to preserve an alkaline pH, advantageously between 8 and 11, in particular so as to prevent corrosion of metal surfaces.

[0221] The pH regulator can be chosen from the amine family, in particular alkanolamines and amino alcohols.

[0222] It may in particular be a pH regulating additive chosen from ethanolamines, such as monoethanolamine (MEA), diethanolamine (DEA); triethanolamine (TEA), diglycolamine (DGA); isopropanolamines, such as monoisopropanolamine (MIPA), diisopropanolamine (DIPA) and triisopropanolamine (TIPA), ethylene amines, such as ethylene diamine (EDA), diethylene triamine (DETA), triethylene tetramine (TETA) and tetraethylene pentamine (TEPA), alkanolamines, such as methyldiethanolamine (MDEA), cyclamines, such as cyclohexylamine, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1-propanol and mixtures thereof.

[0223] An additive composition according to the invention may in particular comprise from 0.1% to 10% by mass of pH regulating additive(s), preferably from 0.5% to 8% by mass, relative to the total mass of the additive composition according to the invention.

[0224] The additive composition according to the invention may also comprise at least one metal passivating agent. Metal passivating agents make it possible to protect metal parts by promoting the formation of metal oxide on their surface.

[0225] The metal passivating agents may be, for example, selected from triazole derivatives, such as tetrahydrobenzotriazole (THBTZ), tolyltriazole (TTZ), benzotriazole (BTZ), triazole-substituted amines, such as N,N-bis(2-ethylhexyl)-1,2,4-triazol-1-yl methanamine, N'-bis(2-ethylhexyl)-4-methyl-1H-benzotriazol-1-methylamine, N,N-bis(heptyl)-ar-methyl-1H-benzotriazol-1-methanamine, N,N-bis(nonyl)-ar-methyl-1H-benzotriazol-1-methanamine, N,N-bis(decyl)-ar-methyl-1H-benzotriazol-1-methanamine, N,N-bis(undecyl)-ar-methyl-1H- benzotriazole-1 -methanamine, N,N-bis(dodecyl)-ar-methyl-1 H-benzotriazole-1 - methanamine, N,N-bis(2-ethylhexyl)-ar-methyl-1 H-benzotriazole-1 -methanamine, 1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles, 2-(N,N-dialkyldithiocarbamoyl)benzothiazoles, 2,5-bis(alkyldithio)-1,3,4-thiadiazoles, such as 2,5-bis(tert-octyldithio)-1,3,4-thiadiazole, the,

[0226] 2.5-bis(tert-nonyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-decyldithio)-1,3,4-thiadiazole,

[0227] 2.5-bis(tert-undecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-tridecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-tetradecyldithio)-1 ,3,4-thiadiazole, 2,5-bis(tert-pentadecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-hexadecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-heptadecyldithio)-1,3,4-thiadiazole, 2,5- bis(tert-octadecyldithio)-1 ,3,4-thiadiazole, 2,5-bis(tert-nonadecyldithio)-1,3,4-thiadiazole, 2,5-bis(tert-eicosyldithio)-1,3,4-thiadiazole, 2,5-bis(N,N-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles, 2-alkyldithio-5-mercaptothiadiazoles, and mixtures thereof.

[0228] Preferably, the metal passivating agents are chosen from tetrahydrobenzotriazole (THBTZ), tolyltriazole (TTZ), benzotriazole (BTZ), and their salts, taken alone or in mixtures.

[0229] An additive composition according to the invention may in particular comprise from 0.01% to 10.0% by mass of metal passivating agent(s), preferably from 0.1% to 5.0% by mass, more preferably from 0.2% to 3.0% by mass, relative to the total mass of the additive composition.

[0230] The additive composition according to the invention may also comprise one or more colorants. The colorants may be natural or synthetic, generally organic.

[0231] The colorants that can be used in an aqueous lubricant composition can be more particularly chosen from natural or synthetic water-soluble colorants, for example the colorants FDC Red 4, DC Red 6, DC Red 22, DC Red 28, DC Red 30, DC Red 33, DC Orange 4, DC Yellow 5, DC Yellow 6, DC Yellow 8, FDC Green 3, DC Green 5, FDC Blue 1, betanin (beetroot), carmine, a chlorophyllin, methylene blue, anthocyanins (enocyanin, black carrot and hibiscus), caramel and riboflavin.

[0232] An additive composition according to the invention may comprise between 0.01% and 2.0% by mass of colorant(s), preferably between 0.01% and 1.5% by mass, more preferably between 0.02% and 1.0% by mass, relative to the total mass of the additive composition.

[0233] The additive composition according to the invention may also comprise one or more emulsifying agents, also called emulsifiers. Their function is to generate stable emulsions in water.

[0234] The emulsifying agents may be more particularly non-ionic, such as for example ethoxylated fatty alcohols, ethoxylated fatty acids, compounds resulting from the reaction between propylene oxide, ethylenediamine and optionally ethylene oxide of ethoxylated fatty amides; anionic, for example KOH, NaOH soaps; sulphonates; cationic, such as quaternary ammonium compounds; or carboxylic acid esters soluble or emulsifiable in water. In particular, an additive composition according to the invention may comprise from 0.01% to 10% by mass of emulsifying agent(s), preferably from 0.1% to 5.0% by mass, relative to the total mass of the additive composition.

[0235] The additive composition according to the invention may comprise at least one sequestering agent. Sequestering agents, also called chelating agents, make it possible to limit the encrustation of metal ions in the composition.

[0236] Examples of sequestering agents include those derived from phosphonic acids and phosphonates, such as diethylenetriaminepentamethylphosphonic acid (DTPMPA), aminotri(methylenephosphonic acid) (ATMP), hydroxyethanediphosphonic acid (HEDP), 1,1-hydroxyethylidene diphosphonate, 2-hydroxyethylamine di(methylenephosphonic acid) (HEAMBP), diethylenetriaminopenta(methylenephosphonic acid) (DTMP), multifunctional organic acids and hydroxy acids, such as ethylenediaminetetraacetic acid (EDTA), pteroyl-L-glutamic acid (PGLU), organic polyacids, such as maleic acid and polyaspartic acid, and carbohydrates, such as inulin, carboxymethylinulin, and carboxymethylchitosan.

[0237] An additive composition according to the invention may comprise from 0.001% to 2.0% by mass of sequestering agent(s), preferably from 0.01% to 1.0% by mass, relative to the total mass of the composition.

[0238] The additive composition according to the invention may comprise at least one biocidal agent with bactericidal and / or fungicidal action. The biocides may be used to improve the biological stability of the composition by limiting the proliferation of bacteria, fungi and yeasts in the lubricating fluid.

[0239] Such biocides may be selected from parabens, aldehydes, reactive acetylacetone compounds, isothiazolinones, phenolic compounds, acid salts, halogenated compounds, quaternary ammoniums, certain alcohols and mixtures thereof.

[0240] Preferably, the biocides may be chosen from optionally substituted benzisothiazolinones (BIT), such as N-butyl-1,2-benzisothiazolin-3-one, methylisothiazolinones (MIT), mixtures of methylisothiazolinone and chloromethylisothiazolinone (MIT / CMIT), orthophenyl-phenol (OPP) or its sodium salt, 3-iodo-2-propynylbutylcarbamate (IPBC), chloro-cresol and N,N-methylene-bis-morpholine (MBM); sorbic acid; preferably from orthophenyl-phenol (OPP) or its sodium salt, 3-iodo-2-propynylbutylcarbamate, chloro-cresol, benzisothiazolinones and N,N-methylene-isomorpholine.

[0241] An additive composition according to the invention may in particular comprise between 0.01% and 10% by mass of biocide(s), preferably between 0.1% and 5.0% by mass, relative to the total mass of the composition.

[0242] According to a second embodiment, the additive composition is intended to be integrated into a fuel composition.

[0243] Thus, according to this embodiment, the additive composition according to the invention may comprise all types of additives suitable for use as a fuel composition, in particular chosen from detergent additives, anti-corrosion agents, dispersants, demulsifiers, anti-foam agents, biocides, reodorants, procetane additives, friction modifiers, lubricity additives or smoothness additives, combustion aid agents (catalytic combustion and soot promoters), agents improving the cloud point, the pour point, the TLF ("Filtrability Limit Temperature"), anti-sedimentation agents, anti-wear agents, conductivity modifying agents and mixtures thereof.

[0244] Among these additives, mention may be made in particular of: a) procetane additives, in particular (but not limited to) chosen from alkyl nitrates, preferably 2-ethylhexyl nitrate, aryl peroxides, preferably benzyl peroxide, and alkyl peroxides, preferably tert-butyl peroxide; b) anti-foam additives, in particular (but not limited to) chosen from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides derived from vegetable or animal oils.Examples of such additives are given in EP861882, EP663000, EP736590; c) Cold flow improver additives (CFI) selected from ethylene and unsaturated ester copolymers, such as ethylene / vinyl acetate (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA), and ethylene / alkyl fumarate copolymers described, for example, in US3048479, US3627838, US3790359, US3961961 and EP261957; (d) lubrication additives or anti-wear agents, in particular (but not limited to) chosen from the group consisting of fatty acids and their ester or amide derivatives, in particular glycerol monooleate, and mono- and polycyclic carboxylic acid derivatives. Examples of such additives are given in the following documents: EP680506, EP860494, WO98 / 04656, EP915944, FR2772783, FR2772784.(e) cloud point additives, including (but not limited to) those selected from the group consisting of long chain olefin / ester terpolymers.

[0245] (meth)acrylic / maleimide, and polymers of fumaric / maleic acid esters. Examples of such additives are given in FR2528051, FR2528051, FR2528423, EP112195, EP172758, EP271385, EP291367; f) detergent additives, in particular (but not limited to) chosen from the group consisting of succinimides, polyetheramines and quaternary ammonium salts; for example those described in documents US4171959 and W02006135881. g) polyfunctional cold operability additives chosen from the group consisting of olefin- and alkenyl nitrate-based polymers as described in EP573490.

[0246] These additives are generally present in the additive composition according to the invention in a content ranging from 100 to 1,000 ppm (each).

[0247] Applications

[0248] An additive composition according to the invention is intended to be used in all types of lubricating compositions or fuel compositions.

[0249] In particular, and when incorporated into a lubricating composition, the resulting lubricating composition may in particular be used for any known application.

[0250] The additive composition according to the invention can thus be used to prepare a lubricating composition for a motor vehicle, preferably comprising at least one combustion engine, in particular in heavy vehicles or light vehicles.

[0251] In particular, the additive composition according to the invention can be used to prepare a lubricating composition intended to lubricate the parts of an internal combustion engine, in particular of the spark ignition type, preferably a gas, gasoline, diesel or even hybrid engine, and more particularly intended to lubricate the parts of a diesel engine.

[0252] The additive composition may also be used to prepare a lubricating composition, in particular an aqueous lubricating composition according to the invention, intended to be used in a metalworking process.

[0253] In particular, the additive composition according to the invention can be used to prepare a lubricating composition intended to be used in any metal machining operation, for example in shaping, cutting, joining processes or any other transformation of the metal such as forming, stamping, rolling, etc. The resulting lubricating composition can be intended to be used for working various metals, such as aluminum, steel, galvanized steel or even yellow metals.

[0254] The resulting lubricating composition advantageously reduces friction between the tool or machining equipment and the machined metal part.

[0255] The invention thus relates to a process for preparing a lubricating composition, said process comprising the following successive steps: i) providing an additive composition as defined above, ii) diluting said additive composition in one or more lubricating oil(s), optionally at least partly re-refined.

[0256] When the additive composition according to the invention is integrated into a fuel composition, the resulting lubricating composition can in particular be used in any known application, in particular in all types of engine depending on the nature of the base fuel used.

[0257] In particular, the additive composition according to the invention is suitable for the preparation of a liquid fuel composition for an internal combustion engine.

[0258] In particular, the additive composition according to the invention can be used for the preparation of a fuel composition intended to be used in:

[0259] - a spark ignition engine, preferably direct injection (DISI in English “Direct Injection Spark Ignition engine”), or

[0260] - a Diesel engine, preferably a direct injection Diesel engine, in particular a Diesel engine with a Common-Rail injection system (CRDI in English “Common Rail Direct Injection”).

[0261] The invention further relates to a process for preparing a fuel composition, said process comprising the following successive steps: i) providing an additive composition as defined above, ii) diluting said additive composition in one or more base fuels, in particular liquid fuel(s).

[0262] The liquid fuel is advantageously derived from one or more sources selected from the group consisting of mineral, animal, vegetable and synthetic sources. Petroleum will preferably be chosen as the mineral source.

[0263] The liquid fuel is preferably chosen from hydrocarbon fuels and non-essentially hydrocarbon fuels, alone or in a mixture.

[0264] Hydrocarbon fuel means a fuel consisting of one or more compounds consisting solely of carbon and hydrogen. Non-essentially hydrocarbon fuel means a fuel consisting of one or more compounds consisting not essentially of carbon and hydrogen, i.e. which also contain other atoms, in particular oxygen atoms.

[0265] Hydrocarbon fuels include in particular middle distillates with boiling points ranging from 100 to 500°C or lighter distillates with a boiling point in the gasoline range. These distillates may, for example, be chosen from distillates obtained by direct distillation of crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates resulting from catalytic cracking and / or hydrocracking of vacuum distillates, distillates resulting from ARDS (atmospheric residue desulfurization) and / or visbreaking conversion processes, distillates resulting from the upgrading of Fischer Tropsch cuts. Hydrocarbon fuels are typically gasolines and diesel fuels (also called diesel fuel).

[0266] Gasoline includes, in particular, all commercially available spark-ignition engine fuel compositions. A representative example is gasoline meeting the NF EN 228 standard. Gasoline generally has octane numbers high enough to avoid knocking. Typically, gasoline-type fuels marketed in Europe, meeting the NF EN 228 standard, have a motor octane number (MON) greater than 85 and a research octane number (RON) of at least 95. Gasoline-type fuels generally have a RON ranging from 90 to 100 and a MON ranging from 80 to 90, with RON and MON being measured according to ASTM D 2699-86 or D 2700-86.

[0267] Diesel fuels include, in particular, all commercially available diesel engine fuel compositions. Examples include diesel fuels that comply with standard NF EN 590.

[0268] Non-primarily hydrocarbon fuels include oxygenates, for example, distillates resulting from the BTL (biomass to liquid) conversion of plant and / or animal biomass, taken alone or in combination; biofuels, for example, vegetable and / or animal oils and / or oil esters; biodiesels of animal and / or plant origin and bioethanols.

[0269] Mixtures of hydrocarbon fuel and non-primarily hydrocarbon fuel are typically Bx type diesel or Ex type gasoline.

[0270] Diesel fuel type Bx for diesel engines is defined as a diesel fuel containing x% (v / v) of esters of vegetable or animal oils (including used cooking oils) transformed by a chemical process called transesterification, obtained by reacting this oil with an alcohol to obtain fatty acid esters (FAE). With methanol and ethanol, fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAE) are obtained, respectively. The letter "B" followed by a number indicates the percentage of FAE contained in the diesel fuel. Thus, a B99 contains 99% EAG and 1% middle distillates of fossil origin (mineral source), B20, 20% EAG and 80% middle distillates of fossil origin etc.... We therefore distinguish between B0 type diesels which do not contain oxygenated compounds, and Bx type diesels which contain x% (v / v) of vegetable oil or fatty acid esters, most often methyl esters (EMHV or EMAG).When EAG is used alone in engines, the fuel is referred to as B100.

[0271] Type Ex petrol for spark-ignition engines means a petrol fuel which contains x% (v / v) of oxygenates, generally ethanol, bioethanol and / or ethyl-tert-butyl-ether (ETBE).

[0272] The invention also relates to the use of an at least partly re-refined lubricating oil, preferably as defined above, as a solution fluid, in particular as a base oil, in an additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition.

[0273] For the purposes of the invention, the term "dissolving fluid" means a liquid substance capable of forming a homogeneous solution with other substances, in particular with conventional additives for lubricants or fuels. Depending on the chemical nature of the additives, the dissolving fluid may be a dilution fluid or a dissolution fluid.

[0274] For the purposes of the invention, the term "dilution fluid" means a fluid capable of diluting, by mixing a homogeneous solution, one or more usual liquid additives.

[0275] For the purposes of the invention, the term "dissolving fluid" means a fluid capable of dissolving one or more usual solid additives, to form a mixture in the form of a homogeneous solution.

[0276] The present invention finally relates to the use of an at least partly re-refined lubricating oil, preferably as defined above, to reduce and / or reduce the carbon footprint of an additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition, compared to the same additive composition prepared from a virgin (or new or even native) base oil.

[0277] More particularly, the invention aims to reduce the carbon footprint by using the aforementioned additive composition, and therefore by using at least one at least partly re-refined base oil, in comparison with the use of an additive composition prepared from a new (or native) base oil.

[0278] The invention is illustrated by the following examples given without limitation.

[0279] EXAMPLES

[0280] The ability of different lubricating oils to solubilize different common additives for lubricating or fuel composition was evaluated / estimated by molecular modeling.

[0281] Base oils evaluated

[0282] The base oils evaluated are defined below:

[0283] - H1 oil (comparative): native mineral oil of group I,

[0284] - H2 oil (comparative): hydrocracked or hydroisomerized native group III oil,

[0285] - H3 oil (according to the invention): partly re-refined mineral oil,

[0286] - H4 oil (according to the invention): partly re-refined mineral oil,

[0287] - H5 oil (according to the invention): partly re-refined mineral oil,

[0288] - H6 oil (according to the invention): partly re-refined mineral oil.

[0289] The main physicochemical characteristics of H1 and H2 oils and partially re-refined lubricating oils H3 to H6 are given in the following Table 2.

[0290] [T able 2]

[0291] The additives tested

[0292] The following common additives were used:

[0293] - Additive A1: ashless dispersant of the borated polyisobutylene succinimide type, with a polyisobutylene chain having a molecular mass (Mn) equal to 300 g. mol -1 ,

[0294] - Additive A2: anti-wear agent of organic phosphate ester type (CAS: 39464-69-2).

[0295] The modeling method

[0296] The ability of different lubricating oils H1 to H6 to solubilize the additives A1 and A2 defined above was evaluated using thermodynamic methods based on conductor-like screening models (COSMO) derived from the use of solvation thermodynamics and computational quantum mechanics. These methods rely on molecule-specific sigma profiles. A sigma profile is the probability distribution of a molecular surface segment with a specific charge density. The model used here is a thermodynamic model called I COSMO-RS (realistic solvation) and developed by Klamt et al. More specifically, the Sigma profiles of additive compositions consisting of a specific oil and additive were modeled. Sigma profiles are one of the fundamental elements of a COSMO-RS calculation.They are also widely used as an important empirical descriptor for the behavior of a molecule in a solution as well as for the properties of a molecule in a number of applications. In the standard COSMO-RS workflow, sigma profiles are generated after a sequence of DFT calculations. Thus, it is possible from the generated sigma profiles for a specific oil and / or for a defined additive to estimate the solvency potential of the additive in question in the desired oil.

[0297] Thus, from the generated sigma profiles, the solubility of the additive in the oil considered was estimated.

[0298] The results

[0299] The results obtained are reported in Table 3 below.

[0300] [Table 3]

[0301] It is observed that additives A1 and A2 are insoluble in native base oils H1 and H2. These additives are however soluble in at least partly re-refined mineral oils H3 to H6.

[0302] Mineral oils that are at least partly re-refined H3 to H6 therefore have increased solvent power compared to native base oils H1 and H2.

Claims

CLAIMS 1. Additive composition, in particular intended to be incorporated into a lubricating composition or into a fuel composition, comprising: - at most 60% by mass of at least one lubricating oil which is at least partly re-refined, - at least 40% by mass of at least one additive chosen from the usual additives for lubricating compositions and / or for fuel compositions, in particular chosen from friction modifying additives, anti-wear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant (PPD) additives, dispersants, anti-foaming agents, thickeners, anti-corrosion agents, corrosion inhibitors, metal passivating agents, pH regulating additives, colorants, emulsifying agents, sequestering agents, biocidal agents, demulsifiers, reodorants, procetane additives, friction modifiers, lubricity additives or smoothness additives, combustion aids, cloud point improvers, limit temperature improvers filterability, anti-sedimentation agents,conductivity modifying agents and mixtures thereof, wherein the at least partly re-refined lubricating oil has a Noack volatility of less than or equal to 15%., 2. Additive composition according to claim 1, in which the at least partly re-refined lubricating oil comes from a used lubricant having been subjected to one or more prior steps of dehydration, distillation, filtration, hydrogenation, liquid / liquid extraction, decantation and / or passage of the used lubricant over an adsorbent material.

3. Additive composition according to claim 1 or claim 2, wherein the at least partly re-refined lubricating oil has a kinematic viscosity, measured at 100°C according to ASTM D445, greater than or equal to 5 mm 2 / s, in particular between 5 and 12 mm 2 / s, more particularly between 5 and 10 mm 2 / s.

4. An additive composition according to any preceding claim, wherein the at least partly re-refined lubricating oil has a viscosity index greater than or equal to 100, in particular between 100 and 130, in particular between 102 and 125.

5. Additive composition according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a Noack volatility of between 8% and 15%, preferably strictly less than 13.5%, and more particularly of between 8% and 13.2%.

6. Additive composition according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a sulfur content of between 0.02% and 0.3% by mass, relative to the total mass of said partly re-refined lubricating oil.

7. Additive composition according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a content of aromatic compound(s) greater than or equal to 0.5% by mass, in particular greater than or equal to 1% by mass, in particular between 1% and 25% by mass, more particularly between 2.5% and 20% by mass, relative to the total mass of said partly re-refined lubricating oil.

8. An additive composition according to any one of the preceding claims, wherein the at least partly re-refined lubricating oil has a density of less than or equal to 880 kg / m 3 , notably between 830 and 880 kg / m 3 , in particular less than or equal to 875 kg / m 3 , and more particularly between 840 and 875 kg / m 3 .

9. Additive composition according to any one of the preceding claims, in which the at least partly re-refined lubricating oil has a thermal conductivity, measured at 100°C and at atmospheric pressure, greater than or equal to 125 mW / mK, in particular between 125 and 145 mW / mK, in particular greater than or equal to 128 mW / mK and more particularly between 128 and 140 mW / mK.

10. Additive composition according to any one of the preceding claims, further comprising one or more base oils distinct from the re-refined lubricating oil, in particular chosen from virgin base oils.

11. Additive composition according to any one of the preceding claims, wherein said at least one additive is selected from antioxidants, pour point depressants (PPD), viscosity index (VI) improvers, antioxidants and mixtures thereof, preferably selected from pour point depressants (PPD), viscosity index (VI) improvers and mixtures thereof.

12. Use of an at least partly re-refined lubricating oil as a solution fluid, in particular as a base oil, in an additive composition according to any one of the preceding claims.

13. Use according to claim 12, for reducing the carbon footprint of said additive composition, compared to the same additive composition prepared from a virgin base oil.

14. A process for preparing a lubricating composition, said process comprising diluting an additive composition according to any one of claims 1 to 11 in a lubricating oil, optionally at least partly re-refined.

15. A method of preparing a fuel composition, said method comprising diluting an additive composition according to any one of claims 1 to 11 in a fuel.

Images