EP0738776A1 - Colloidal alkali or alkaline-earth metal carbonates containing a calcium phosphorous and sulphur compound in micellar form - Google Patents

Abstract

A colloidal prod. comprises micelles of an alkali and/or alkaline earth carbonate maintained in the colloidal state by an alkyl- or alkylaryl-sulphonate of an alkali or alkaline earth metal. In addn. it contains (maintained in the colloidal state by the surfactant of the pre-existent micellar structure) a prod. contg. Ca, P and S, resulting from the in situ reaction of CaO or Ca(OH)2 with a phosphorus sulphide and water. The structure of this prod. corresps to that of a thiophosphate or polythiophosphate of Ca.

Description

The present invention relates to colloidal products. of the hyperbasic sulfonate type and their use as additives for lubricants.

In an earlier French patent FR - B - 2 698 018, the same applicant has already described colloidal products obtained by micellization of the product of the reaction of calcium oxide or hydroxide with a phosphorus sulfide such as tetraphosphorus decasulfide , and water, produced in the presence of a surfactant such as an alkyl arylsulfonic acid or a calcium salt of such an acid. In the present application, the colloidal products are no longer obtained in the presence of surfactant but in the presence of a pre-existing micelle.

Indeed, we have now discovered that it was possible to micellize the product of the reaction of calcium oxide or hydroxide with tetraphosphorus decasulfide and water within a pre-existing micelle of alkaline or alkaline earth carbonate stabilized by an alkali or alkaline earth metal alkyl- or alkylarylsulfonate (the latter being said: "overbased" or "hyperbasic").

The products of the invention can be defined in general by the fact that they consist of colloidal products comprising micelles of alkaline or alkaline-earth carbonate maintained in the colloidal state by a surfactant consisting of at least one alkali or alkaline earth metal alkyl or alkylarylsulfonate and further comprising, maintained in the colloidal state by the surfactant of the pre-existing micelle, a product containing calcium, phosphorus and sulfur resulting from the in situ reaction of calcium oxide or hydroxide with a phosphorus sulfide, in general tetraphosphorus decasulfide, and water. The structure of this product corresponds to that of at least one thiophosphate and / or at least one calcium polythiophosphate.

Obtaining the products of the invention therefore brings into play, as starting products, alkali or alkaline earth alkylsulfonates or alkylarylsulfonates, for example sodium, potassium, calcium or magnesium, overbased with an alkaline or alkaline earth carbonate, such than calcium, magnesium, sodium or potassium carbonate. Such alkylsulfonates and alkylarylsulfonates derive from the corresponding acids, which have been described in numerous documents, for example in FR - B-2 101813. The overbased alkyl or alkylarylsulfonates used can have a basicity reserve of 50 to approximately 500 or more (total basic index expressed in mg of potash per gram of product).

Most often the phosphorus sulfide involved is the tetraphosphorus decasulfide P ₄ S ₁₀ .

• o le rapport molaire de l'oxyde ou de l'hydroxyde de calcium au sulfure de phosphore peut aller de 4/1 à 20/1;
• o le rapport molaire de l'eau au sulfure de phosphore peut aller de 2/1 à 20/1; et
• o le sulfure de phosphore est mis en jeu en une proportion de 1 à 30 g pour 100 g d'alkyl ou d'alkylarylsulfonate surbasé.

The reagents used are dispersed calcium oxide or hydroxide, phosphorus sulfide and water in the following proportions:

• o the molar ratio of calcium oxide or hydroxide to phosphorus sulfide can range from 4/1 to 20/1;
• o the molar ratio of water to phosphorus sulfide can range from 2/1 to 20/1; and
• o the phosphorus sulfide is used in a proportion of 1 to 30 g per 100 g of overbased alkyl or alkylarylsulfonate.

At the start of the reaction, the overbased alkali or alkaline earth metal alkyl or alkylarylsulfonate is in colloidal solution in a solvent which may consist of an aliphatic hydrocarbon (such as, for example, hexanes, heptanes or octanes); aromatic (such as toluene or xylenes); cycolaliphatic (such as, for example, cyclohexane); a chlorinated hydrocarbon (such as, for example, mono- or dichlorobenzene); or an ether (such as tetrahydrofuran for example).

It is also possible to use a dilution oil consisting of a mineral or synthetic oil such as a lubricating oil, optionally with one of the solvents mentioned above.

The reaction temperature can generally range from room temperature to 170 ° C, more particularly to the reflux temperature of the selected solvent.

The products according to the invention can be obtained by the process as described above in the presence of an oil and then most often contain from 30 to 70% by mass of active material. They generally have a calcium content of up to 30% by mass; a sodium content of 5 to 30% by mass when the starting substrate is colloidal sodium carbonate; a phosphorus content of 0.5 to 10% by mass and a sulfur content of 1 to 20% by mass.

The micelle core contains the starting alkaline or alkaline earth carbonate as well as an additional quantity of micellized calcium, phosphorus and sulfur compound, probably in the form of calcium thiophosphate.

It may be noted at this stage of the description of the present invention that, in an earlier French patent FR - B - 2 698 019, the same applicant had already described the modification of micelles of calcium carbonate or of magnesium by the product of the reaction of tetraphosphorus decasulfide and water. In this case, the acid formed - presumably thiophosphoric acid - reacted with the colloidal calcium or magnesium carbonate present.

In a different manner, in the present application, the thiophosphoric acid formed reacts preferentially with the added calcium oxide or hydroxide, without consuming the basic reserve of the alkali or alkaline earth carbonate already micellized. This reaction mode is confirmed by the analysis of the calcium content before and after the reaction, as well as by the determination of the total basic index, which is not affected by the reaction.

The colloidal nature of the products of the invention is checked by dialysis through a latex membrane. The sulfur and / or phosphorus analyzes locate these elements in the fraction that has not dialyzed (concentrate), which constitutes the colloidal part of the additive. The colloidal products of the invention retain the well-known detergent properties of the overbased starting products from which they are derived.

They also have antiwear and extreme pressure properties. Antiwear and extreme pressure additives are incorporated in lubricants when they are intended to lubricate organs subjected to significant mechanical stresses, such as distribution in heat engines, gears, bearings and stops. Significant mechanical stresses also appear during the machining of metals, whether cutting or forming.

In addition, the colloidal products of the invention are endowed with great thermal stability, which authorizes their use in lubricants subjected in service at very high temperatures which can reach 200 ° C., as in certain severe motor casings, in heavily loaded transmissions or high speed metal cutting.

In the use of the products of the invention as additives for lubricating oils and greases, they can be incorporated into them, for example at a concentration of 0.1 to 25% by mass, preferably from 1 to 15% by mass .

Lubricating oils (or greases) also generally contain one or more additives such as viscosity index additives, pour point lowering additives, antioxidants, rust inhibitors, anticorrosive additives for copper , detergents, antiwear, antifoam, dispersants, friction reducers, with which the products of the invention are compatible.

The following examples illustrate the invention without limiting it.

In Examples 1 to 5, the preparation of products according to the invention is carried out from colloidal substrates consisting of calcium or sodium alkylarylsulfonates called hyperbasic noted A, B and C, of which the alkaline reserve is essentially constituted calcium carbonate and sodium carbonate respectively. Their characteristics are as follows: Substrate Alkaline reserve TBN (1) Active ingredient (2) (mass%) Oil (2) (mass%) Ca or Na (mass%) S (mass%) AT CaCO3 300 59 41 11.6 1.8 B CaCO3 500 61.8 38.2 18.6 1.3 VS Na2CO3 377 59.1 40.9 15.7 1.8 (1) Total basic index expressed in mg of potash per g of product (ASTM D 2896) (2) Determination by dialysis

Example 1

• Ca = 14,7%
• P = 2,3%
• S = 6,2%

50 g of hyperbasic calcium sulfonate A dissolved in 250 ml of xylene and 50 ml of tetrahydrofuran are introduced into a reactor, then 6 g (0.0135 mole) of tetraphosphorus decasulfide and 15 g (0.267 mole) of lime CaO are dispersed. Then a solution of 4.9 g of water in 50 ml of tetrahydrofuran is introduced over an hour at 30 ° C. with constant stirring. The medium is stirred for 3 hours, then the tetrahydrofuran and the excess water are removed by distillation. After returning to ambient temperature, the medium is filtered and the filtrate is evaporated under reduced pressure. A homogeneous liquid product is collected, the mass concentrations of which are as follows:

• Ca = 14.7%
• P = 2.3%
• S = 6.2%

Example 2

• Ca = 11,3 %
• P= 2,4 %
• S= 6,4 %

50 g of hyperbasic calcium sulfonate A dissolved in 250 ml of xylene, 30 g of 130 Neutral oil and 50 ml of tetrahydrofuran are introduced into a reactor, then 10 g (0.0225 mole) of tetraphosphorus decasulfide and 20 g (0.357) are dispersed mole) of lime CaO. Then a solution of 8.1 g of water in 50 ml of tetrahydrofuran is introduced over an hour at 30 ° C. with constant stirring. The medium is stirred for 3 hours, then the tetrahydrofuran and the excess water are removed by distillation. After returning to ambient temperature, the medium is filtered and the filtrate is evaporated under reduced pressure. A homogeneous liquid product is collected, the mass concentrations of which are as follows:

• Ca = 11.3%
• P = 2.4%
• S = 6.4%

Example 3

• Ca = 21,1 %
• P = 1,9 %
• S = 5,7 %

50 g of hyperbasic calcium sulfonate B dissolved in 250 ml of xylene and 50 ml of tetrahydrofuran are introduced into a reactor, then 5 g (0.0113 mole) of tetraphosphorus decasulfide and 20 g (0.27 mole) of lime Ca are dispersed (OH) 2. Then a solution of 4.1 g of water in 50 ml of tetrahydrofuran is introduced over an hour at 30 ° C. with constant stirring. The medium is stirred for 3 hours, then the tetrahydrofuran and the excess water are removed by distillation. After returning to ambient temperature, the medium is filtered and the filtrate is evaporated under reduced pressure. A homogeneous liquid product is collected, the mass concentrations of which are as follows:

• Ca = 21.1%
• P = 1.9%
• S = 5.7%

Example 4

• Ca = 22,3 %
• P = 2,4 %
• S = 6,7 %

50 g of hyperbasic calcium sulfonate B dissolved in 250 ml of xylene and 50 ml of tetrahydrofuran are introduced into a reactor, then 6 g (0.0135 mole) of tetraphosphorus decasulfide and 20 g (0.357 mole) of lime CaO are dispersed. Then a solution of 4.9 g of water in 50 ml of tetrahydrofuran is introduced over an hour at 30 ° C. with constant stirring. The medium is stirred for 3 hours, then the tetrahydrofuran and the excess water are removed by distillation. After returning to ambient temperature, the medium is filtered and the filtrate is evaporated under reduced pressure. A homogeneous liquid product is collected, the mass concentrations of which are as follows:

• Ca = 22.3%
• P = 2.4%
• S = 6.7%

Example 5

• Na = 15,6 %
• Ca =1,3 £à
• P = 1,4 %
• S = 3,9 %

50 g of hyperbasic sodium sulfonate C dissolved in 250 ml of xylene and 50 ml of tetrahydrofuran are introduced into a reactor, then 4 g (0.009 mole) of tetraphosphorus decasulfide and 20 g (0.357 mole) of lime CaO are dispersed. Then a solution of 3.2 g of water in 50 ml of tetrahydrofuran is introduced over an hour at 30 ° C. with constant stirring. The medium is stirred for 3 hours, then the tetrahydrofuran and the excess water are removed by distillation. After returning to room temperature, the medium is filtered and the filtrate is evaporated under reduced pressure. A homogeneous liquid product is collected, the mass concentrations of which are as follows:

• Na = 15.6%
• Ca = £ 1.3 at
• P = 1.4%
• S = 3.9%

EXAMPLE 6 Examination of the Products by Dialysis

The products of Examples 1 to 6 are dialyzed in n-heptane through a latex membrane. The non-colloidal fraction (dilution oil) called dialysate dialysis through the membrane while the colloidal fraction called concentrate is retained inside it. The localization of calcium, sodium, phosphorus and sulfur in the fraction which has not been dialyzed confirms the colloidal nature of the products of the invention. The calcium concentration in the active ingredient is higher for each of the modified products than that of its precursor. This confirms the incorporation into the micelle of additional calcium from the dispersed lime present during the synthesis.
The results are collated in Table 1.

Example 7 : Evaluation of antiwear and extreme pressure performance

The products of the invention prepared as described in examples 1 to 5 above are characterized by their antiwear and extreme pressure properties in a 130 Neutral solvent mineral oil at a concentration which makes it possible to adjust the concentration of active material to 7, 5% by mass. The characterization is carried out using a 4-ball machine according to the ASTM D2783 test. The results are collated in Table 2. Also included are the results obtained with the unmodified hyperbasic sulfonates A, B and C evaluated at the same concentration. Examination of the results confirms the best antiwear and extreme pressure performance of the products of the invention (products of examples 1 and 2 compared to A, examples 2 and 3 compared to B, example 5 compared to C). Table 2 Example product Active mat concentration / 130N (% by mass) Welding load (daN) Load / wear index (saN) Footprint diameter after 1 hour / 40 daN (mm) 1 7.5 300 43 0.42 2 7.5 360 45 0.45 3 7.5 400 65 0.34 4 7.5 410 63 0.35 5 7.5 340 60 0.38 AT 7.5 220 32 0.41 B 7.5 280 43 0.34 VS 7.5 260 49 0.53

Claims (11)

Colloidal product comprising carbonate micelles of at least one alkali metal and / or at least one alkaline earth metal maintained in the colloidal state by at least one alkyl or alkylarylsulfonate of alkali or alkaline earth metal, characterized in that that it further comprises, maintained in the colloidal state by the surfactant of the pre-existing micelles, in the form of micelles, a product containing calcium, phosphorus and sulfur, resulting from the in situ reaction of oxide or calcium hydroxide with phosphorus sulfide and water; the structure of this product corresponding to that of at least one thiophosphate and / or at least one calcium polythiophosphate. Colloidal product according to claim 1, characterized in that it comprises micelles of sodium, potassium, calcium or magnesium carbonate maintained in the colloidal state by an alkyl or an alkylarlylsulfonate of sodium, potassium, calcium or magnesium. Colloidal product according to claim 1 or 2, characterized in that the initial alkyl or alkylarylsulfonate has a basicity reserve of approximately 50 to 500 mg of potassium hydroxide per gram. Colloidal product according to one of claims 1 to 3, characterized in that said phosphorus sulfide is tetraphosphorus decasulfide. Colloidal product according to one of Claims 1 to 4, characterized in that, for the micellization of the product containing calcium, phosphorus and sulfur, the phosphorus sulfide is used in an amount of 1 to 30 g per 100 g alkyl or alkylarylsulfonate; calcium oxide or hydroxide, in an amount of 4 to 20 moles per mole of phosphorus sulfide; and water, at a rate of 2 to 20 moles per mole of phosphorus sulfide. Colloidal product according to one of claims 1 to 5, characterized in that the reaction is carried out in a solvent chosen from hydrocarbons aliphatic, aromatic, or cycolaliphatic, chlorinated hydrocarbons and ethers, and / or in a dilution oil, at a temperature between room temperature and 170 ° C. Colloidal product according to one of claims 1 to 6, characterized in that it comprises a dilution oil and a proportion of 30 to 70% by mass of active material. Colloidal product according to one of Claims 1 to 7, characterized in that it contains up to 30% by mass of calcium, optionally from 5 to 30%, by mass of sodium, from 0.5 to 10% by mass of phosphorus and from 1 to 20% by mass of sulfur. Use of a colloidal product according to one of claims 1 to 8 as an additive with detergent and / or antiwear and extreme pressure action in oils or thick lubricants. Composition of lubricating oil or grease characterized in that it contains from 0.1 to 25% by mass of at least one colloidal product according to one of claims 1 to 8. Composition of lubricating oil or grease according to Claim 10, characterized in that the said colloidal product is incorporated in a concentration of 1 to 15% by mass.