BRPI0906868B1 - METHOD FOR PREPARING A LUBRICANT COMPOSITION - Google Patents

Description

"METHOD FOR PREPARING A LUBRICANT COMPOSITION" The present invention relates to a method for preparing a lubricant composition, especially a grease.

Alkyl substituted quinolines and polymerized derivatives thereof are known to be very effective, low cost antioxidants for various uses, including use in lubricating compositions.

As an example, WO 94/24235 discloses the use of alkyl-substituted 1,2-dihydroquinolines (including monomers, dimers, trimers and tetramers thereof) in motor oils, transmission oils, gear oils, working fluids. metal, hydraulic fluids, greases and the like. Illustrative examples of these substituted alkyl 1,2-dihydroquinolines are 2,2,4-trimethyl-1,2-dihydroquinoline, 2-methyl-2,4-diethyl-1,2-dihydroquinoline, 2,2,4,6 -tetramethyl-1,2-dihydroquinoline, 2,2,4,7-tetramethyl-1,2-dihydroquinoline, 6,6'-bis (2,2,4-trimethyl-1,2-dihydroquinoline) and the like .

In addition, US 5,246,606 shows that dimeric, trimeric, and tetrameric tetrahydroquinoline derivatives are suitable for stabilizing organic materials against light-induced thermal and / or oxidative degradation. US 5,246,606 suggests the use of these compounds, among others, in functional fluids such as lubricants and hydraulic fluids.

Despite substituted alkyl quinazolines such as 2,2,4-trimethyl-1,2-dihydroquinoline (also referred to as "TMQ", "TMDQ" and "TMHQ") and oligomeric derivatives (ie, dimeric, trimeric and tetrameric) of the Even though they are widely used as antioxidants, they have many disadvantages.

As an example, TMQ is in the form of a brittle solid at room temperature and usually in the form of a mixture of monomers and oligomers, it has no well-defined melting point. Although it becomes soft when the temperature rises, it is still a very viscous and fibrous material at typical additive addition temperatures around 80 to 100 ° C.

If TMQ is added to lubricating compositions such as greases in this typical temperature range of 80 to 100 ° C, it will not be properly dispersed within the grease and will result, for example, in filter blockage, in grease delivery systems. . Even if the filter loading of these grease delivery systems is not sufficient for the filter to be blocked immediately, some of the oxidant will have been removed from the grease, which will result in a reduction in life.

In view of the above, alkyl-substituted quinolines are usually added to the greases at temperatures above 150 ° C, usually between 150 - 160 ° C, after the grease completes its critical cooling phase and after the establishment of the system. thickening in the base oil.

However, a problem associated with the known method is that the window of opportunity for the addition of alkyl-substituted quinolines is usually narrow if they are to be properly dispersed in the grease. The alkyl substituted quinolines are added, for example, 10 minutes later, and this may be too late because the grease may have been cooled too much.

Another problem with the known method of adding alkyl-substituted quinolines to grease at relatively high temperatures is that the most severe health and safety problems, for example related to the risks of high-temperature grease and other hazards, must be taken into account. the danger of vapor release when the manufacturing vessel has to be opened.

An object of the present invention is to avoid the above problems.

Another objective is to present an alternative method for preparing a lubricating composition, especially a grease.

One or more of the above or other objects are achieved by the present invention by presenting a method for preparing a lubricant composition, especially a grease, the method comprising at least the steps of: a) producing a composition base oil optionally containing one or more additives; b) producing a solution of one or more alkyl substituted quinolines or oligomeric derivatives thereof in a solvent; and c) adding the solution of step b) to the base oil composition of step a) at a temperature below 150 ° C.

Surprisingly, according to the present invention, it has been found that if alkyl substituted quinolines (or oligomeric derivatives thereof) are added in a solvent to the base oil composition, they can be added at a lower temperature thereto. further obtaining an appropriate dispersion thereof in the base oil composition.

An important advantage of the present invention is that alkyl-substituted quinolines (or oligomeric derivatives thereof) may be added at a lower temperature, resulting in less stringent safety requirements. There is also more flexibility at the time of addition of alkyl-substituted quinolines (or oligomeric derivatives thereof), because the specific temperature for their addition is less critical than when no solvent is used.

Preferably in step c) the solution of step b) is added at a temperature below 120 ° C, preferably in the range 10 to 110 ° C, more preferably 15 to 100 ° C.

According to an especially preferred embodiment of the present invention, one or more alkyl substituted quinolines are alkyl substituted 1,2-dihydroquinolines (or oligomeric derivatives thereof). Preferably one or more substituted alkyl 1,2-dihydroquinolines have the general formula (I) wherein R 1 -R 8 are independently selected from hydrogen or an alkyl group having 1-8 carbon atoms; and n is 0, 1, 2 or 3.

Preferably R 8 R 8 are independently selected from hydrogen, or an alkyl group having 1-4 carbon atoms, preferably having 1-2 carbon atoms. Preferably R4 is H. It is even more preferable that R4-R8 are all H. It is also preferred that R4-R3 are all a methyl group.

In addition, one or more alkyl-substituted 1,2-dihydroquinolines preferably have a mean value of n of from 1.0 to 2.0, preferably from 1.3 to 1.6. It is also preferred that one or more alkyl substituted quinolines provided in the solution have a solubility below 0.1% as determined using ASTM D893.

Alkyl substituted quinoline compounds (or oligomeric derivatives thereof) as used in the present invention are commercially available or may be prepared by various reactions which are known in the art. Examples of preparation methods have been set forth in WO 94/24235 and US 5,246,606 mentioned above and in the references cited therein, the teachings of which are incorporated herein by reference. Other examples are set forth in US 4,692,258 and US 3,910,918, and in the references cited therein, the teaching of which is incorporated herein by reference as well.

A specific example for the preparation of TMQ (2,2,4-trimethyl-1,2-dihydroquinoline) was given in W. R. Vaughan, "Organic synthesis", Collective Volume III, pp 329-30, (1955). There are no specific limitations on the solvent used in the method according to the present invention, and various conventional solvents may conveniently be used.

Preferably the solvent is composed of a polyglycol, more preferably a polyalkylene glycol. Polyglycols are well known in the art and will no longer be discussed here in detail.

As an example, polyalkylene glycols (PAG) may have alkylene oxide units of 1 to 6 carbon atoms (-R-O-) as monomer units.

Polyalkylene glycols may have hydrogen terminal groups, alkyl, aryl, alkylaryl, aryloxyl, alkoxy, alkylaryloxy and / or hydroxyl groups. Alkylaryloxy groups are to be understood to mean oxyarylalkylene groups, and alkylaryl groups mean arylalkylene groups (e.g., aryl CH 2 CH 2 -). Alkyl-type terminal groups, including alkoxy type, or aryl type groups, including alkylaryl type, aryloxyl type and alkylaryloxy type, preferably have 6 to 24 carbon atoms, especially preferably 6 to 18 atoms. carbon atoms based on aryl types and preferably 1 to 12 carbon atoms based on alkyl types.

Polyalkylene glycols according to the invention may be homopolymers, specifically polypropylene glycol (and / or polypropylene oxide) or copolymers, terpolymers, etc. In the latter case, monomer units may have either a random distribution or a block structure. If the polyalkylene glycols are not homopolymers, preferably at least 20%, preferably at least 40% of all monomer units may be produced from polypropylene oxide (PO), and also preferably at least 20%. % of all monomer units of these polyalkylene glycols can be produced using ethylene oxide (EO) (PO / EO copolymers). According to another embodiment, preferably at least 20%, preferably at least 40% of all monomer units may be produced from butylene oxide (BO) and more preferably at least 20% of all monomer units of these polyalkylene glycols can be obtained using ethylene oxide (BO / EO copolymers).

When polyalcohols are used, the starting compound is incorporated into the polymer and, according to the meaning of the invention, is also referred to as the polymer chain end group. Suitable starting groups consist of compounds consisting of active hydrogen such as n-butanol, propylene glycol, ethylene glycol, neopentyl glycols such as pentaerythritol, ethylenediamine, phenol, cresol or others (Cl a 06 (mono, di or trialkyl Aromatic, (hydroxyalkyl) aromatic, hydroquinone, aminoethanolamines, triethylenetetramines, polyamines, sorbitol or other sugars Other CH acidulated compounds such as carboxylic acids or carboxylic anhydrides may also be used as starting compounds.

Preferably, the polyalkylene glycols are aryl groups or corresponding heteroaromatic groups, for example, inserted into the polymer chain as secondary groups or terminal groups; groups, if necessary, may be substituted by straight or branched alkyl groups or alkylene groups, alkyl groups or alkylene groups generally having from 1 to 18 carbon atoms. Cyclic ether alcohols, such as hydroxyfurfuryl or hydroxy tetrahydrofuran, heterocyclic nitrogen or heterocyclic sulfur, may also be used as starting groups. Such polyalkylene glycols are set forth in WO 01/57164, the teachings of which are incorporated herein by reference.

Preferably the polyalkylene glycols according to the invention have an average molecular weight (number average) of 200 to 3,000 g / mol, more preferably 400 to 2,000 g / mol. The kinematic viscosity of polyalkylene glycols preferably is 10 to 400 mm2 / s (cSt) measured at 40 ° C according to DIN 51562.

The polyalkylene glycols used according to the invention may be produced by the reaction of alcohols, including polyalcohols, as starting compounds with oxiranes, such as ethylene oxide, propylene oxide and / or butylene oxide. After the reaction they have only one free hydroxyl group as terminal group. Polyalkylene glycols with only one hydroxyl group are preferred over those with two hydroxyl groups. Polyalkylene glycols which, for example, after an additional etherification step, no longer contain any free hydroxyl groups, are especially preferred with respect to stability, hygroscopicity and compatibility. Alkylation of terminal hydroxyl groups leads to an increase in thermal stability. Accordingly, in an especially preferred embodiment according to the present invention, the PAG base oil is comprised of end capped PAG, i.e. where no hydroxyl group is present. Neopentyl polyol esters may also be used in place of the polyalkylene glycols described above.

Neopentyl polyol esters such as neopentyl glycol, pentaerythritol and trimethylol propane with linear or branched C4 to C12 monocarboxylic acids, for example, with the addition of the corresponding dicarboxylic acids, are suitable neopentyl polyol esters. Usually pentaerythritol is obtained as a technical grade pentaerythritol, which is a mixture of monopentaerythritol, dipentaerythritol and tri- pentaerythritol. However, their condensation products such as dipentaerythritol and / or tripentaerythritol are also suitable as alcoholic components. Pentaerythritol or mixtures with dipentaerythritol and / or tri-pentaerythritol, preferably mixtures consisting predominantly of dipentaerythritol, are especially suitable. Complexed esters may be produced by proportional esterification of polyhydric alcohols with monovalent and divalent acids such as C4 to C12 dicarboxylic acids. In this way, dimers and oligomers are formed. When using neopentyl glycol and / or trimethylolpropane as the alcohol group, complexed esters are preferred. There is no specific limitation on the composition of the base oil used in the method according to the present invention, and various conventional mineral oils and synthetic oils may conveniently be used. For the purposes of this description, the term "base oil" means also including a grease-based feedstock. The base oil composition used in the present invention may conveniently consist of mixtures of one or more mineral oils and / or one or more synthetic oils.

Mineral oils include petroleum liquid oils and solvent treated or acid treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic / naphthenic type which may be further refined by hydro-finishing and / or grease elimination processes. .

Suitable base oils for use in the lubricating oil composition of the present invention are group I, group II or group ΠΙ base oils, polyalphaolefins, Fischer-Tropsch-derived base oils and mixtures thereof. The "group I" base oil, the "group Π" base oil and the "group ΙΠ" base oil in the present invention mean base oils of lubricating oil according to the definitions of categories I, II and ΙΠ of " American Petroleum Institute (API). ”These API categories are defined in API publication, 15th Edition, Appendix E, April 2002.

Suitable base oils derived from Fischer-Tropsch which could conveniently be used as the base oil in the lubricating oil composition of the present invention are those, for example, disclosed in EP 0 776 959, EP 0 668 342, WO 97/21788, WO 00/15736, WO 00/14188, WO 00/14187, WO 00/14183, WO 00/14179, WO 00/08115, WO 99/41332, EP 1 029 029, WO 01/18156 and W01 / 57166.

Synthetic oils include hydrocarbon oils such as olefin oligomers (PAOs), dibasic acid esters, polyol ethers, and degreased grease raffinate. Synthetic hydrocarbon base oils sold by the Shell Group under the name "XHVI" (trade mark) may be used conveniently. The total amount of base oil incorporated in the lubricant composition of the present invention is preferably present in an amount in the range of 60 to 92 wt.%, More preferably in an amount in the range of 75 to 90 wt.%. preferably in an amount ranging from 75 to 88% by weight, based on the total weight of the lubricant composition.

If desired, the final lubricating composition may further comprise one or more additives such as antioxidants, anti-wear agents, dispersants, detergents, friction modifiers, viscosity index promoters, flow point depressants, binding agents, inhibitors. corrosion suppressants, emulsion scavengers, foam scavengers and seal compatibility or seal fixation agents, etc.

As the person skilled in the art is familiar with the above and other additives, this will no longer be discussed here. The additives may be added to the base oil composition before or after being added in step c) one or more alkyl substituted quinolines. Also, if appropriate, additives may be added at the same time with one or more alkyl-substituted quinolines.

Said additives typically are present in an amount in the range of 0.01 to 12.5% by weight based on the total weight of the lubricant composition, preferably in an amount in the range of 0.05 to 10.0%. more preferably by weight from 1.0 to 9.0% by weight, and more preferably in the range from 2.0 to 5.0% by weight based on the total weight of the lubricant composition.

As the lubricant composition may also be (and preferably is) in the form of a grease, the base oil contained in the lubricant composition may contain or consist of one or more thickeners, such as metal soaps, organic substances or inorganic substances, for example. lithium soaps, lithium complex soaps, sodium terephthalate, urea / urethane compounds and clays.

Preferably, the lubricating composition has a kinematic viscosity in the range 2 to 80 mm2 / s at 100 ° C, more preferably in the range 3 to 70 mm2 / s, more preferably in the range 4 to 50 mm2 / s .

The lubricating compositions of the present invention may conveniently be prepared by mixing one or more base oils and optionally one or more additives which are usually present in the lubricating compositions, for example as described hereinbefore with a base oil. mineral and / or synthetic. Preferably, and as is customary in the art, one or more substituted alkyl quinoline compounds (or oligomeric derivatives thereof) have a sufficiently small particle size (e.g., less than 50 micrometres, preferably below 20 micrometres), to allow easy dispersion thereof in the lubricant composition.

In another aspect, the present invention features a lubricating composition, especially a grease, obtained by the method according to the present invention. The present invention is described below with reference to the following examples, which are not intended to limit the scope of the present invention in any way.

Examples Solutions of alkyl-substituted quinolines - Solution A

A solution at 50¾ m / m 500 ml oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline (solid; available from Rhein Chemie Rheinau GmbH under the tradename "Additin RC7010") on polyalkylene glycol (available from Dow Chemical Company, USA, under the tradename "Oxilube 504 '') was prepared by heating the polyalkylene glycol to 100Â ° C prior to the addition of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline. Oligomeric 4-trimethyl-1,2-dihydroquinoline was added slowly over about 2 minutes allowing it to be dispersed through the fluid before further addition.The mixture thus obtained was stirred for a further 30 minutes at 100 ° C. A homogeneous, stable solution was formed.

- Solution B

Similarly to solution A, a 50% w / w solution of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline, 500 ml in polyglycol (available from Dow Chemical Company, USA, as "Synalox 50-50B"). A stable, homogeneous solution was formed. Example 1 A grease was prepared using the above solution A (50 ml) and a conventional grease base material (4,950 g). The conventional grease-based feedstock contained about 10% w / w lithium complex thickener and about 90% w / w paraffinic mineral base oil mixed from SN 500 and high viscosity deparaffinized lubricant (viscosity at 40 ° C 180mm% according to ASTM D445) The conventional grease-based feedstock also contained an anti-wear additive (a zinc dialkyl dithiophosphate), an extreme pressure additive (a stifling ester). ) and a rust inhibitor (a zinc naphthenate) .The grease-based raw material a and solution A were simply mixed for 30 minutes using a laboratory paddle mixer, after both were preheated to 80 ° C prior to mixing.

After visual inspection, no apparent deficiencies were found in the obtained grease. No agglomerations were formed. No separation of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline from grease occurred after 12 months of storage. Other properties of the obtained grease are given below in Table I.

Table I

The results in table I show that the desired properties for a grease, such as mechanical stability, oil retention, and surprisingly also water stability, are still present in the example I grease and are not affected by the presence of the solvent ( polyalkylene glycol) used to dissolve oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline.

Example ... 2 Similarly to example 1, a grease was prepared using solution B.

After visual inspection no apparent deficiency was found in the obtained grease. No agglomerations were formed.

There was also no separation of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline from grease after 12 months of focusing. As in example 1, the grease of example 2 showed the desired properties of mechanical stability, oil retention and water stability.

Comparative Example 1 A grease was prepared using the same amount of oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline (without solvent) and the same grease-based raw material as in Examples 1 and 2. The grease base was heated to about 160 ° C. Then a portion of the oligomeric 2,2,4-trimethyl-1,2-dihydroqumoline was added to the base material of the heated grease and left at this temperature for about 10 minutes. Mixing was done using a laboratory bread mixer until the mixture reached a temperature of about 60 ° C.

Then the mixture was reheated to about 160 ° C and left at this temperature for about 30 minutes. Subsequently, the addition and mixing steps were repeated until all of the oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline was added and mixed.

Upon visual inspection, no apparent deficiency was found in the obtained grease. No agglomerations were formed.

Comparative Example 2 Similar to Comparative Example 1, a grease was prepared, although the heating was around 60 ° C (rather than about 160 ° C). It was not possible to disperse oligomeric 2,2,4-trimethyl-1,2-dihydroquinoline in the grease-based feedstock, which would lead to severe blockages in the filter if grease in comparative example 2 is used, for example. in grease management systems.

Discussion As can be seen from the examples, the present invention allows the addition of alkyl substituted quinolines or oligomeric derivatives thereof at a significantly lower temperature while still obtaining a stable grease having the desired properties. Needless to say, this is highly desired from a health and safety perspective as well as from a practical manufacturing perspective. In this regard, it is noted that if no solvent is used (see comparative example 2) while adding alkyl substituted quinolines or oligomeric derivatives thereof, no stable grease is obtained.

Claims (7)

Method for the preparation of a lubricating composition, especially a grease, characterized in that it comprises at least the steps of: (a) producing a base oil composition, optionally containing one or more additives; b) producing a solution of one or more alkyl-substituted 1,2-dihydroquinolines or oligomeric derivatives thereof, in a solvent, wherein the alkyl-substituted 1,2-dihydroquinolines have the general formula (i) where R'- R 2 are independently selected from hydrogen or an alkyl group having 1-8 carbon atoms; and enO, 1,2, or 3, and wherein the solvent is a polyglycol; and c) adding the solution of step b) to the base oil composition of step a) at a temperature in the range of 10 to 110 ° C. Method according to claim 1, characterized in that in step c) the solution of step b) is added at a temperature of 15 to 100 ° C. A method according to either claim 1 or claim 2, wherein R 2 R 2 are independently selected from hydrogen or an alkyl group having 1-4 carbon atoms, preferably having 1-2 carbon atoms. Method according to any one of claims 1 to 3, characterized in that RJ-R8 is hydrogen. Method according to any one of claims 1 to 4, characterized in that one or more alkyl-substituted 1,2-dihydroquinolines has a mean value of n of 1.0 to 2.0, preferably of 1, 3 to 1.6. Method according to any one of claims 1 to 5, characterized in that one or more alkyl-substituted 1,2-dihydroquinolines provided in the solution have a solubility below 0.1% as determined using ASTM D 893. Method according to any one of claims 1 to 6, characterized in that the solvent comprises a polyalkylene glycol.