WO2009027428A2

WO2009027428A2 - Lubricating composition comprising fluorine oil and tricalcium phosphate

Info

Publication number: WO2009027428A2
Application number: PCT/EP2008/061215
Authority: WO
Inventors: Takahiro Ozaki; Tetsuya Katou; Koichi Numazawa
Original assignee: Shell Internationale Research Maatschappij B.V.
Priority date: 2007-08-28
Filing date: 2008-08-27
Publication date: 2009-03-05
Also published as: WO2009027428A3; JP5525149B2; JP2009227958A

Abstract

Lubricating composition comprising fluorine oil and tricalcium phosphate. Preferably the tricalcium phosphate is used at from 1% to 40% by mass relative to the total composition. The lubricating composition of the present invention has excellent heat resistance, load resistance, fire resistance, and a long life at elevated temperatures, without using a fluororesin or the fluorine solvent to dissolve it.

Description

LUBRICATING COMPOSITION

Technical Field of the Invention

This invention relates to an improvement in lubricating compositions and in particular relates to a lubricating composition with excellent heat resistance and load resistance.

Background of the Invention

Hitherto, lithium soap grease compositions prepared by adding a lithium salt of a fatty acid to a mineral oil or a synthetic oil (Japanese Laid-Open Patent H5-86392 (1993)) or aluminium complex soap grease compositions, or urea grease compositions prepared by reacting an isocyanate and an amine in a mineral oil or a synthetic oil to form a urea compound (Japanese Laid-Open Patent H6-330072 (1994)), have been used for lubricating compositions such as greases that require heat resistance and load resistance.

There has also been a proposal, as a means of improving heat resistance, to obtain urea grease compositions by using urea compounds which have fluorine atoms within the molecular skeleton (Japanese Laid-Open Patent Hll-61169 (1999)), but these have drawbacks in that they have a special structure and are generally difficult to obtain.

Fluorine-based grease compositions in which the base oil is a perfluoropolyether of a fluorine oil, this being thickened by means of a fluororesin, are known as a means of further improving heat resistance (Japanese Laid-Open Patent 2007-154084) . Such fluorine-based grease compositions are being used for lubrication under elevated temperatures exceeding 150⁰C, for lubrication at points that come into contact with chemical products, for lubrication under high vacuum, for lubrication subject to irradiation, and also for lubrication at points where long life is required in various kinds of precision apparatus .

However, the aforementioned fluorine-based grease compositions have drawbacks associated with manufacturing costs in that it is necessary, at the time of manufacture, to heat and dissolve the fluororesin in a fluorine solvent, to disperse it within the fluorine oil constituting the base oil, and further to treat it by means of a depressurising apparatus in order to remove the fluorine solvent from the grease composition produced. Moreover, the aforementioned fluororesin and the fluorine solvent used to dissolve it are expensive, so that the cost of fluorine-based grease compositions becomes higher still, and for this reason their application has been substantially limited in spite of their excellent performance.

Detailed Description of the Invention

This invention offers at low cost, a high- performance fluorine-based lubricating composition with excellent heat resistance, load resistance and fire resistance, by obtaining a fluorine-based lubricating composition safely and easily, without using a fluororesin or the fluorine solvent to dissolve it.

Fluorine-based greases have excellent heat resistance and oxidative stability, and yet have the property of being virtually insoluble in organic solvents or oils and fats. For this reason, their compatibility with various kinds of additives is poor, and, depending on the lubrication materials and the conditions of use, there are many instances where wear is accelerated or rust is produced.

This invention offers a fluorine-based lubricating composition which reduces the friction coefficient and improves wear resistance under rigorous lubrication conditions .

This invention also offers a fluorine-based lubricating composition with excellent rust-preventing performance . The inventors have discovered that, when tricalcium phosphate is added to a fluorine oil, it exhibits an extremely good thickening effect. They have also discovered that a fluorine-based lubricating composition thus prepared has excellent heat resistance and load resistance, so that it is possible to sustain its performance over long periods at elevated temperatures, and so they have arrived at this invention.

In other words, this invention will produce a fluorine-based lubricating composition by incorporating tricalcium phosphate in a fluorine oil.

The tricalcium phosphate may be used at a level of from about 1% to about 40% by mass relative to the total composition including the fluorine oil. Also, this tricalcium phosphate can be used together with other thickeners .

According to the present invention, it is possible to obtain a lubricating composition with excellent heat resistance and load resistance and with a long life at elevated temperatures. Also, tricalcium phosphate is more economic than a fluororesin and the fluorine solvent to dissolve it, so that it is possible to obtain safely and easily a lubricating composition which is advantageous in cost terms. Also, when tricalcium phosphate is used, the cost of raw materials is lower and the penetration yield is better than ordinary fluorine greases. In other words, it is possible to obtain a lubricating composition of the requisite hardness with a smaller amount of thickener. Whilst the lubricating composition of this invention can naturally be used in applications such as ordinarily used machinery and bearings, it exhibits superior performance under lubricating conditions where more rigorous high-temperature properties are required. For example, in automobiles, mention may be made of engine peripherals such as starters, alternators and various actuator parts, power lines such as propeller shafts, constant velocity joints (CVJ), wheel bearings and clutches, and various components such as electric power steering (EPS), damping devices, ball joints, door hinges, handle parts and cooling fans. It is suitable for these applications.

Furthermore, it is also suitable for construction machinery such as power shovels, bulldozers and cranes, and in various high-temperature locations such as iron and steel, the paper-making industry, forestry, agricultural machinery, chemical plant, drying ovens and copying machines .

Other applications include use in hard-disk bearings, use in plastic lubricants, cartridge greases and so on, and it is also suitable for these applications .

The aforementioned fluorine oil can be, for example, a perfluoropolyether or a fluorosilicone, and it is possible to use at least one of these or a suitable mixture .

For this fluorine oil, mention may be made of perfluoropolyether and derivatives thereof, fluorosilicone, chlorotrifluoroethylene and fluorophosphazene and so on, and mention may also be made of mixtures thereof.

The type of perfluoropolyether is not specially limited, but those which are constituted from at least one of the fluorooxyalkylene structural units as shown below are preferred.

X in the undermentioned chemical structures (6) and (7) is "CF₃(CF₂) _n~" , and n is an integer of from 0 to 4. -(-CF₂CF₂O-)- (1)

-(-CF₂O-)- (2)

-(-CF₂CF(CF₃)O-)- (3)

-(-CF(CF₃)O-)- (4)

-(-CF₂CF₂CF₂O-)- (5) -(-CF₂CF(OX)O-)- (6); and

-(-CF(OX)O-)- (7)

When the perfluoropolyether is constituted from two or more kinds of the aforementioned fluorooxyalkylene structural units, each structural unit is to be distributed statistically along chains. The terminal groups are fluoroalkyl groups which may have arbitrarily one H and/or Cl, such as CF₃-, C₂F₅-, C₃F₇-, CF₂Cl(CF₃)CF-, CF₃CFClCF₂-, CF₂ClCF₂-, CF₂Cl-, CHF₂- and CF₃CHF-.

What is meant by the fluorosilicones of this invention are fluorosilicones having substituent groups containing fluorine atoms. They are not specially limited so long as they have a viscosity within a range where they may be used as a mineral oil for a lubricating composition . As specific examples of fluorosilicones suitable for use, mention may be made of those represented by the undermentioned Formula (8), but they are not limited to these . Further, it is possible to add other known lubricating compositions to the perfluoropolyethers or fluorosilicones so long as they do not interfere with the specific purpose of this invention.

In the aforementioned equation 8, R¹ is a hydrocarbon group with from 1 to 3 carbon atoms and R² is a methyl group, an ethyl group, a vinyl group, a phenyl group or a -CH₂CH₂R group (wherein R is a perfluoroalkyl group having from 1 to 10 carbons), at least 50% of the aforementioned R² being -CH₂CH₂R groups. Also, n is an integer within a range which gives a practicable viscosity range.

The aforementioned tricalcium phosphate is one having the chemical structure of a hydroxyapatite composition as generally represented by

[Ca₃ (PO4)₂] ₃-Ca(OH) ₂, but it is also possible to use those represented by Ca₃ (PO₄) ₂.

In the examples described below for this invention, [Ca₃ (PO₄) ₂] ₃ -Ca (OH) ₂ is used, and the content is shown as the mass based on this.

It is possible to obtain the lubricating composition by thorough mixing and kneading after adding the tricalcium phosphate to the aforementioned fluorine oil. The consistency of the lubricating composition increases according to an increase in the amount of tricalcium phosphate added, and as the consistency of the lubricating composition increases so it gradually takes on the form of a grease.

When obtaining a lubricating composition in the form of a grease, the amount of tricalcium phosphate used in the blend is from about 1% to about 40% by mass relative to the total lubricating composition, but is preferably from about 5% to about 20% by mass and more preferably from about 7% to about 15% by mass.

If the amount of tricalcium phosphate in the blend is less than 1% by mass, a form is obtained that would not normally be called a grease, but as an increase in consistency is seen, it is possible to use it in applications that call for the form obtained. Also, if the amount exceeds 40% by mass, the lubricating composition becomes hard, and as it is not like smooth butter it may not be considered as a grease, but it can be used in applications where such a form is suitable.

In addition to the aforementioned constituents, it is possible also to use in the lubricating composition of this invention, where suitable and as required, rust preventatives, corrosion inhibitors, anti-oxidants, extreme pressure agents, anti-wear agents and other additives .

For the aforementioned rust preventatives and corrosion inhibitors, those generally used may be mentioned, but of these it is particularly good to have at least one kind selected from alkali metal salts of dibasic acids, alkaline earth metal salts of dibasic acids or benzotriazole derivatives, benzothiazole derivatives, benzoimidazole derivatives or thiocarbamates . Particularly preferred are sodium sebacate and benzotriazole, or these used in combination. Also, for the anti-oxidants it is possible to use, for example, amine-based, phenol-based, phosphate-based, sulphur-based and dialkyl dithiophosphate anti-oxidants.

For the extreme-pressure agents and anti-wear agents, it is possible to use sulphur compounds such as sulphided oils and fats, sulphided olefins or dithiocarbamate salts as exemplified by zinc dithiocarbamate and molybdenum dithiocarbamate, phosphorus compounds such as phosphate esters, acidic phosphate esters, phosphite esters, acidic phosphite esters, amine salts of phosphate esters, amine salts of phosphite esters, amine salts of acidic phosphate esters and amine salts of acidic phosphite esters, and sulphur- phosphorus compounds such as thiophosphate esters, or dithiophosphate compounds as exemplified by zinc dithiophosphates and molybdenum dithiophosphates .

Together with the aforementioned tricalcium phosphate which functions as a thickener, it is also possible to use (as mixtures) other thickeners in the lubricating composition of this invention. For these other thickeners it is possible to use, for example, urea compounds, alkali metals soaps, for example, lithium soaps, alkali metal complex soaps, for example lithium complex soaps, alkaline earth metal soaps, for example calcium soaps, alkaline earth metal complex soaps, alkali metal sulphonates, alkaline earth metal sulphonates, aluminium soaps, aluminium complex soaps, terephthalamate metal salts, for example sodium terephthalate, clays and polytetrafluoroethylenes, and these may be used either singly or as mixtures.

The aforementioned other thickeners may form part of the lubricating composition of this invention by being mixed into the fluorine oil together with the tricalcium phosphate. It is also possible to make the lubricating oil of this invention by mixing together a lubricating composition prepared by using fluorine oil and tricalcium phosphate and a lubricating composition prepared by using other thickeners and fluorine oil or a base oil other than fluorine oil.

Where such other thickeners are also used, it can be best if the aforementioned rust preventatives, corrosion inhibitors, anti-oxidants, extreme-pressure agents, anti- wear agents and other additives are mixed in by adding them to a lubricating composition prepared by using other thickeners and a base oil other than fluorine oil, and in addition mixed in to a lubricating composition prepared by using fluorine oil and tricalcium phosphate. If this is done, it is effective in making it possible for additives that are difficult to mix with the fluorine oil to mix in more easily.

Examples

Further explanation is given below by means of examples and comparative examples, but the invention is not limited by these. Example 1

450 g of GPL106 (viscosity: 240 mm²/s at 40⁰C and 25 mm²/s at 100⁰C) made by Dupont Ltd. of the USA were drawn off as the perfluoropolyether . 50 g of tricalcium phosphate were added, and after kneading at room temperature the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. The amount of tricalcium phosphate included was 10.0% by mass. Example 2

450 g of GPL107 (viscosity: 440 mm²/s at 40⁰C and 42 mm²/s at 100⁰C) made by Dupont Ltd. of the USA were drawn off as the perfluoropolyether . 50 g of tricalcium phosphate were added, and after kneading at room temperature the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. The amount of tricalcium phosphate included was 10% by mass. Example 3

425 g of FL-100-lOOOCS (viscosity: 1000 mm²/s at 25°C) made by Shin-Etsu Chemical Industries Ltd. were drawn off as the fluorosilicone . 75 g of tricalcium phosphate were added, and after kneading at room temperature the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. The amount of tricalcium phosphate included was 15% by mass. Example 4

A lubricating composition was obtained by mixing 200 g of the lubricating composition of Example 2 and 200 g of the lubricating composition of Example 3. The amount of tricalcium phosphate included was 12.5% by mass. Examples 5 to 21

As shown in Tables 3 to 12, lubricating compositions were prepared by mixing the lubricating composition of Example 2 with a lubricating composition formed by means of the other thickeners of the below mentioned Comparative Examples 4 to 12. Examples 22 to 24

Fluorine oil (perfluoropolyether GPL107 made by Dupont Ltd. of the USA), tricalcium phosphate, sodium sebacate and/or benzotriazole were added in the blend proportions shown in Table 13, and, after kneading, the mixtures were processed in a three-roll mill to give finished lubricating compositions of uniform state. Comparative Example 1

Commercial lithium-complex soap-based grease: Texaco

Starplex 2 made by Texaco Ltd.

Comparative Example 2 Commercial aluminium-complex soap-based grease:

Omega 57 made by Magna Industrial Co. Ltd.

Comparative Example 3

Commercial urea-based grease: Caltex RPM SRI OEM2 made by Caltex Ltd. Comparative Example 4

Commercial clay-based grease: Aero Shell Grease 22

(ASG) from Shell Aviation Limited.

Comparative Example 5

Lubricating composition prepared using polytetrafluoroethylene : commercial lubricating composition (Fomblin TR-15) which uses fluorine oil as the base oil and polytetrafluoroethylene as the thickener .

Comparative Example 6 Lubricating composition prepared using calcium sulphonate : commercial lubricating composition which uses calcium sulphonate as the thickener (trade name Calforex

EP grease) .

Comparative Example 7 Lubricating composition prepared using a urea compound: In 900 g of refined mineral oil (I) which had a kinetic viscosity at 100⁰C of approximately 33 mm²/s and a kinetic viscosity at 40⁰C of approximately 500 mm²/s,

0.295 mole (38.12 g) of octylamine was reacted in 0.147 mole (36.88 g) of diphenylmethane-4, 4 ' -diisocyanate and then 0.08 mole (14.92 g) of laurylamine was reacted by adding it to 0.04 mole (10.08 g) of diphenylmethane-4, 4 '- diisocyanate, and a lubricating composition was obtained by uniformly dispersing and processing in a three-roll mill. The content of urea compound was 10% by mass. Comparative Example 8

Lubricating composition prepared using a lithium soap: 600 g of lithium 12-hydroxystearate were dissolved in 5400 g of the aforementioned refined mineral oil (I) and, after uniformly dispersing and processing, a lubricating composition was obtained. The lithium soap content was 10% by mass. Comparative Example 9

Lubricating composition prepared using a lithium complex soap: After reacting 350 g of lithium 12- hydroxystearate with 50.5 g of lithium hydroxide in 4165 g of the aforementioned refined mineral oil (I), 120.65 g of azelaic acid was reacted with 59.0 g of lithium hydroxide and a grease was obtained by uniformly dispersing and processing. The content of thickener was 10.4% by mass . Comparative Example 10 Lubricating composition prepared using a calcium soap: 300 g of calcium stearate was dissolved in 2700 g of the aforementioned refined mineral oil (I), and a grease was obtained by uniformly dispersing and processing. The content of thickener was 10% by mass. Comparative Example 11

Lubricating composition prepared using an aluminium complex soap: 158.22 g of benzoic acid and 334.8 g of stearic acid were dissolved in 4272 g of the aforementioned refined mineral oil (I), and then 293.64 g of commercial cyclic aluminium oxide propylate lubricating fluid [trade name: Algomer, made by Kawaken Fine Chemicals Co. Ltd.] was added and a reaction was effected. A grease was obtained by uniformly dispersing and processing the soap produced. The content of aluminium complex soap was approximately 11% by mass. The molar ratio of benzoic acid (BA) and stearic acid (FA) was set at BA/FA = 1.1 and the molar ratio of aluminium (Al) to benzoic acid and stearic acid was set at.(BA÷FA) / Al = 1.9 Comparative Example 12

Lubricating composition prepared using sodium terephthalamate : 294.54 g of methyl N-octadecyl terephthalamate were reacted with 27.36 g of sodium hydroxide in 2700 g of the aforementioned refined mineral oil (I), and a grease was obtained by uniformly dispersing and processing. The content of thickener was 10% by mass . Comparative Example 13

After kneading the fluorine oil (II)

[perfluoropolyether GPL107 made by Dupont Ltd. of the USA] , tricalcium phosphate and calcium sulphonate in the blend proportions shown in Table 13 at room temperature, the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. Comparative Example 14

After kneading the fluorine oil (II), tricalcium phosphate and zinc sulphonate in the blend proportions shown in Table 13 at room temperature, the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. Comparative Example 15

After kneading the fluorine oil (II), tricalcium phosphate and zinc napthenate in the blend proportions shown in Table 13 at room temperature, the mixture was processed in a three-roll mill to give a finished lubricating composition of uniform state. Evaluations of Examples 1 to 24 and Comparative Examples 1 to 15 were made by carrying out tests such as penetration, heat resistance, high-temperature bearing life, load resistance, friction coefficient, wear resistance and bearing rust prevention.

(1) Penetration: The worked penetration (25°C, 60W) was measured in respect of the penetration of the grease state in accordance with JIS K2220 (ASTM D1403), using a Vt scale pug mill. The unworked penetration (25°C, OW) was also measured.

(2) Penetration after heating: The specimen was packed into the ¹A scale pug mill of JIS K2220 (ASTM D1403) and the top surface cut flat. It was then heated for 24 hours at 200⁰C. The specimen was then allowed to cool to room temperature while it was examined for external changes, and the aforementioned unworked penetration (OW) was measured at a temperature of 25°C.

Also, the percentage change in hardness was obtained by means of the following formula: Percentage change in hardness = [ (P₂ - Pi) / P₂] x

100

P₁ = unworked penetration after test P₂ = unworked penetration before test

(3) Thin film evaporation: 1.0 ± 0.1 g of specimen was smeared onto the central area (50 x 70 mm) of one side of a test-piece of the dimensions of thickness stipulated by the humidity cabinet test method of JIS K2246 (1.0 ~ 2.0 mm) x length 60 mm x width 80 mm, and a heating test was carried out at 200⁰C x 24 hours. The state of the specimen after the test was examined, and the amount of evaporation (amount of loss) of the specimen was also obtained as % by mass. (4) High-temperature bearing life: Bearing life tests were carried out in accordance with ASTM D3336 and the bearing life (hours) at 200⁰C was obtained.

(5) Load resistance: Four-ball tests were carried out in accordance with ASTM D2596 under the following conditions, and the wear mark diameter (mm) of the balls was obtained for loads of 50 kg, 63 kg, 80 kg, 100 kg, 126 kg, 160 kg, 200 kg, 250 kg, 315 kg, 400 kg, 500 kg and 600 kg up to weld load (WL; kgf ) . Conditions: Speed: 1770 ± 60 rpm

Time: 10 seconds

Temperature : Room temperature

(6) Falex friction and wear test: The friction coefficient and surface roughness (μm) of a test piece (pin) after 15 minutes from start of the test were obtained under the following conditions (as per IP241/65) .

Conditions: Speed: 290 rpm

Load: 90.7 kg (200 pounds) Temperature: Room temperature

Time: 15 minutes

Amount of sample: Approx. 1 gram of specimen smeared on test piece (7) Bearing rust prevention tests were carried out under the following conditions on the basis of ASTM D1743-73.

Conditions: Temperature: 52⁰C

Time: 48 hours Relative humidity: 100% Re sult s

The results of the tests on Examples 1 to 24 are given in Table 1 and Tables 3 to 13 together with the make-up of the test specimens. The results of the tests on Comparative Examples 1 to 15 are given in Table 2 and Tables 4 to 13. Discussion

As shown in Table 1, the lubricating compositions of Examples 1 to 4 had a percentage hardness change of as little as 5.8% or less and a film evaporation of as little as 22% by weight or less even when heated for 24 hours at 200⁰C.

On the other hand, as shown in Table 2, when the commercial high-temperature greases of Comparative Examples 1 to 3 were heated for 24 hours at the high temperature of 200⁰C, they melted and leaked out of their containers, so that it was impossible to measure their change in hardness. Also, as to the amount of film evaporation, 60% or more by mass evaporated off, and a hardened state after melting was observed.

Also, in the case of high-temperature bearing life tests, Examples 1 to 4 all had a bearing life of more than 200 hours, and in the four-ball EP tests the weld load (WL) was high: 400 kg for Example 1, 500 kg for Example 2, 315 kg for Example 3 and 600 kg for Example 4. The wear mark diameters (mm) on balls at the various loads up to weld load were also small, and the lubrication properties were good. It was evident that Examples 1 to 4 as a whole were lubricating compositions having superior heat resistance, wear resistance and load resistance, and with long life at elevated temperatures.

In contrast, in the bearing life tests Comparative Examples 1 to 3 had bearing lives of 20 hours and 60 hours, and in the four-ball EP tests the weld load (WL) was low: 315 kg for Comparative Example 1, 250 kg for Comparative Example 2, and 126 kg for Comparative Example 3. The wear mark diameters (mm) of balls at the various loads up to weld load (WL) were large, and it was obvious that lubricating performance was not satisfactory.

Examples 5 to 12 as shown in Tables 3 to 12, were instances of mixing with the grease of Example 2, greases formed from the other thickeners of Example 3 or Comparative Examples 4 to 12 and varying the respective amounts in the blend. Example 5 was a mixture of Example 2 and Example 3 at 9 : 1, and the anti-wear properties were rather low but were within permissible limits, while the friction coefficient was better than either individual case. Example 6 was a mixture of Example 2 and Comparative Example 4 at 9 : 1, and the friction coefficient and anti-wear properties were better than either individual case. Example 7 and Example 8 were mixtures of Example 2 and Comparative Example 5 at 9 : 1 and 1 : 9, and the friction coefficient and anti-wear properties were better than either individual case. Example 9 and Example 10 were mixtures of Example 2 and Comparative Example 6 at 9 : 1 and 1 : 9, and for both the friction coefficient and anti-wear properties were better than either individual case. Example 11 was a mixture of Example 2 and Comparative Example 7 at 9 : 1, and the friction coefficient and anti-wear properties were better than either individual case. Example 12 and Example 13 were mixtures of Example 2 and Comparative Example 8 at 9 : 1 and 5 : 5, and for both the friction coefficient and anti-wear properties were better than either individual case. Example 14 was a mixture of Example 2 and Comparative Example 9 at 9 : 1, and the friction coefficient was similar to or better than either individual case, while the anti-wear properties were superior. Example 15 and Example 16 were mixtures of Example 2 and Comparative Example 10 at 9 : 1 and 5 : 5, and for both the friction coefficient and anti-wear properties were better than either individual case. Example 17, Example 18 and Example 19 were mixtures of Example 2 and Comparative Example 11 at 9 : 1, 5 : 5 and 1 : 9, and the friction coefficient was similar to or better than each individual case, while the anti-wear properties for Example 19 were rather lower than for Example 2 but were within a permissible range and so the results were good. Example 20 and Example 21 were mixtures of Example 2 and Comparative Example 12 at 9 : 1 and 5 : 5, and while the anti-wear properties for Example 21 were rather lower than for Example 2 they were within a permissible range, and otherwise better results were obtained than for the individual cases.

Table 13 shows the results of investigations of the effect of adding sodium sebacate or benzotriazole to the grease comprised of fluorine oil and tricalcium phosphate, and of using these together (Examples 22 to 24), and of adding calcium sulphonate, zinc sulphonate or zinc naphthenate (Comparative Examples 13 to 15) . In the case of the Examples using sodium sebacate or benzotriazole or both, no occurrence of rust was seen and it was evident that the rust-preventing effect was high. In contrast, as shown by Comparative Examples 13 to 15, in the case of calcium sulphonate, zinc sulphonate and zinc naphthenate, which are generally known as rust preventatives, rust was observed and it was evident that a rust-preventing effect had not been obtained. Table 1

Table 2

Table

Table 4

Table 5

Table 6

Table 7

Table

Table 9

Table 10

Table 11

Table 12

Table 13

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Claims

C L A I M S

1. Lubricating composition comprising fluorine oil and tricalcium phosphate.

2. Lubricating composition according to Claim 1 comprising from 1% to 40% by weight of tricalcium phosphate relative to the total composition.

3. Lubricating composition according to Claim 1 or Claim 2 wherein the aforementioned fluorine oil comprises a perfluoropolyether or fluorosilicone .

4. Lubricating composition according to any of Claims 1 to 3 further comprising thickening agents, other than tricalcium phosphate, selected from urea compounds, alkali metal soaps, alkali metal complex soaps, alkaline earth metal soaps, alkaline earth metal complex soaps, alkali metal sulphonates, alkali earth metal sulphonates, aluminium soaps, aluminium complex soaps, terephthalamate metal salts, clays or polytetrafluoroethylenes .

5. Lubricating composition according to any of Claims 1 to 3 additionally comprising at least one additive selected from alkali metal salts of dibasic acids, alkaline earth metal salts of dibasic acids, benzotriazole derivatives, benzothiazole derivatives, benzoimidazole derivatives or thiocarbamates .

6. Lubricating composition according to Claim 5 wherein the aforementioned alkali metal salt of a dibasic acid is sodium sebacate.

7. Lubricating composition according to Claim 5 wherein the benzotriazole derivative is benzotriazole.