A hydraulic, lubricating and coupling composition

Abstract: A hydraulic, lubricating and coupling composition which comprises an organopolysiloxane and at least one additive selected from: (i) a phosphorus type or sulfur type anti-wear agent; (ii) a metal deactivator; and (iii) a corrosion inhibitor.

Description: The present invention relates to the use of a hydraulic, lubricating and coupling composition in a fan coupling and to a hydraulic, lubricating and coupling composition for use in a fan coupling. More particularly, it relates to a composition having improved thermal stability which can be used at a high temperature for a long period without a significant increase in viscosity. By way of example, a fan coupling (fan clutch) consists of a body which has a disc at the end of a pump shaft and a wheel at the end of a fan shaft such that the disc and the wheel face each other. The disc rotates with the rotation of the pump, while immersed in a viscous operating oil which is filled in the body, whereby the torque is transmitted to the wheel through the operating oil and as a result the fan rotates. As the operating oil an organopolysiloxane, such as dimethylpolysiloxane or methylphenylpolysiloxane, generally having a high viscosity index, is used. The organopolysiloxane is subjected to thermal degradation or gelation when used at a high temperature because of its poor thermal stability, whereby its viscosity increases and its torque transmission ability cannot be stably maintained. To improve the thermal stability of the organopolysiloxane, it has been proposed to add an antioxidant such as iron octoate, aromatic amine derivatives and ferrocene derivatives. When a composition comprising the organopolysiloxane and the antioxidant is used in a fan coupling, however, an increase in viscosity is observed. EP-A-397,507 was published between the first and second priority dates of the present application. It describes a viscous coupling comprising an organopolysiloxane and a phosphorous type anti-wear agent. The organopolysiloxane has a large viscosity of, for example, 50,000 cSt at 25°C. GB-A-2,206,887 discloses a polysiloxane viscous coupling fluid which may contain sulfur or various sulfur compounds. FR-A-2,455,079 discloses working fluids having a low viscosity of, for example, 92.43 cSt at 37.8°C. GB-A-1,296,163 discloses lubricant compositions comprising, inter alia, an organopolysiloxane and a sulfur containing compound. US-A-4,744,915 discloses a brake fluid having a low viscosity of less than 1,000 cSt. JP-A-2/091,196 discloses viscous coupling compositions comprising a phosphorous or chlorine additive. US-A-3,532,730 discloses a hydraulic fluid having a low viscosity of, for example, 73.7 cSt at 25°C. The present invention seeks to provide a composition whose viscosity increases only very slightly even when used at a high temperature for a long period. The present invention provides the use of a hydraulic, lubricating and coupling composition in a fan coupling, which composition comprises: (i) an organopolysiloxane having a viscosity of 1,000 to 20,000 cSt at 25°C; (ii) a phosphorus type anti-wear agent; and (iii) an antioxidant; said phosphorus type anti-wear agent having one of the following formulae (I) to (VII): wherein each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; each of R₅ to R₇ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms; each of X₁ to X₄ is independently oxygen or sulfur; each Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2, with the proviso that both X₂ and X₃ are sulfur when n is 0; wherein R₁ to R₇, X₁ to X₄, Y and n are as defined in formula (I); wherein each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; each of R₅ and R₆ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms; each of X₁ to X₄ is independently oxygen or sulfur; each Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2; wherein each of R₁ and R₂ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; R₈ is a hydrocarbon group containing from 1 to 20 carbon atoms and containing at least one ester bond; each of X₁ and X₂ is independently oxygen or sulfur; and each Y is independently a direct bond, oxygen or sulfur; (R-Y)₃-P=X a (V) wherein each R-Y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; Y is oxygen or sulfur; and a is 0 or 1; R (3-b) (R-Y) b -P=X a (VI) wherein each R-Y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; Y is oxygen or sulfur; a is 0 or 1; and b is an integer of from 0 to 2; ( (R)₂N) a (RO) b -P=X (VII) wherein each (R)₂N group and each RO group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; a is an integer of from 1 to 3; and b is an integer of from 0 to 2, with the proviso that a+b=3 . The present invention also provides a hydraulic, lubricating and coupling composition for use in a fan coupling which comprises: i) an organopolysiloxane having a viscosity of 1,000 to 20,000 cSt at 25°C; ii) a phosphorus type anti-wear agent as defined above; (iii) an antioxidant; and (iv) a sulfur type anti-wear agent, metal deactivator or corrosion inhibitor. It has been found that by adding a phosphorus type anti-wear agent and an antioxidant, optionally together with at least one of a sulfur type anti-wear agent, metal deactivator or corrosion inhibitor, a coating is formed on a metal surface. It is surmised that this retards any catalyzing action that the metal making up the wheel and disc in the coupling may have on degrading the organopolysiloxane, whereby the increase in viscosity of the composition can be effectively prevented. The organopolysiloxane, which is used as a base oil in the composition according to the present invention, generally has the following formula: wherein each R represents hydrocarbon groups containing 1 to 18 carbon atoms, which may be halogenated, and n is an integer of 1 to 3,000. Examples of suitable hydrocarbon groups include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, neopentyl, hexyl, heptyl, octyl, decyl and octadecyl; aryl groups such as phenyl and naphthyl; aralkyl groups such as benzyl, 1-phenylethyl and 2-phenylethyl; and araryl groups such as o-, m- and p-diphenyl. Methyl and phenyl groups are preferable. Examples of suitable halogenated hydrocarbon groups include o-, m- and p-chlorophenyl, o-, m- and p-bromophenyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, heptafluoro-i-propyl, heptafluoro-n-propyl and trifluoromethylphenyl. Fluorinated aromatic or aliphatic saturated hydrocarbon groups containing 1 to 8 carbon atoms are preferable. The organopolysiloxane can be used as a mixture, such as a mixture of methylpolysiloxane and phenylpolysiloxane. The compounds of formulae (I) to (VII) are the phosphorus type anti-wear agents: Compound of formula (I): Each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; each of R₅ to R₇ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; each of X₁ to X₄ is independently oxygen or sulfur; each Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2, with the proviso that both X₂ and X₃ are sulfur when n is 0. Compound of formula (II): R₁ to R₇, X₁ to X₄, Y and n are as defined in formula (I). Compound of formula (III): Each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; each of R₅ and R₆ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; each of X₁ to X₄ is independently oxygen or sulfur; Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2. Compound of formula (IV): Each of R₁ and R₂ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; R₈ is a hydrocarbon group containing from 1 to 20 carbon atoms and containing at least one ester bond; each of X₁ and X₂ is independently oxygen or sulfur; and each Y is independently a direct bond, oxygen or sulfur. R₁ to R₄ in formulae (I) to (IV) are preferably phenyl or alkylphenyl, considering the heat-resistance. R₁ to R₈ in the formulae (I) to (IV) preferably contain from 1 to 10 carbon atoms, considering their surface adsorbing properties on metals and their solubility in the organopolysiloxane. Compound of formula (V): Each R-Y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; X is oxygen or sulfur; Y is oxygen or sulfur; and a is 0 or 1. The compound of formula (V) includes those having the following structures: Examples of the compound of structure (1) are phosphate esters such as propylphenyl phosphate, butylphenyl phenyl phosphate, ethyl diphenyl phosphate, allyl diphenyl phosphate, ethylphenyl diphenyl phosphate, propylphenyl diphenyl phosphate, butylphenyl diphenyl phosphate, benzyl diphenyl phosphate, cresyl diphenyl phosphate, diethylphenyl phenyl phosphate, dipropylphenyl phenyl phosphate, dibutylphenyl phenyl phosphate, dicresyl phenyl phosphate, triphenyl phosphate, tricresyl phosphate, triethylphenyl phosphate, tripropylphenyl phosphate, tributylphenyl phosphate, dibutyl phosphate and tributyl phosphate; and acid phosphate esters such as lauryl acid phosphate, stearyl acid phosphate and di-2-ethylhexyl phosphate. Examples of the compound of structure (2) are triphenyl phophorothionate and butyl methyl diphenyl phosphorothionate. Examples of the compound of structure (5) are triisopropyl phosphite and diisopropyl phosphite. Example of the compound of structure (6) is trilauryl thiophosphite. The compound of formula (V) is preferably a triarylphosphate of structure (1) or a triaryl phosphorothionate of structure (2), considering the heat stability. Compound of formula (VI): Each R-Y b group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms, preferably a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; X is oxygen or sulfur; Y is oxygen or sulfur; a is 0 or 1; and b is an integer of from 0 to 2. The compound of formula (VI) includes those having the following structures: Compound of formula (VII): Each (R)₂N group and each RO group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; a is an integer of from 1 to 3; and b is an integer of from 0 to 2, with the proviso that a+b=3 . The compounds of formula (VII) include those having the following structures: An example of the compound of structure (7) is di-n-butylhexyl phosphonate. An example of the compound of structure (8) is n-butyl-n-dioctyl phosphinate. An example of the compound of structure (22) is hexamethylphosphoric triamide. An example of the compound of structure (24) is dibutyl phosphoroamidate. Among the phosphorus anti-wear agents, the compounds of formulae (V), (VI) and (VII) are especially preferable. The composition may also comprise a sulfur type anti-wear agent. Examples include sulfides such as diphenyl sulfide, diphenyl disulfide, dibenzyl disulfide, di-n-butyl sulfide, di-n-butyl disulfide, di-tert-dodecyl disulfide and di-tert-dodecyl trisulfide; sulfurized oils and fats such as sulfurized sperm oil and sulfurized dipentene; thiocarbonates such as xanthic disulfide; and zinc thiophosphates such as zinc primary-alkyl thiophosphate, zinc secondary-alkyl thiophosphate, zinc alkyl aryl thiophosphate and zinc aryl thiophosphate. The single use of the phosphorus type anti-wear agent is effective for preventing the increase in viscosity. Because the anti-wear agent adsorbs on metals in the temperature range specified depending on its thermal stability, the combined use of two or more phosphorus type or sulfur type anti-wear agents (so long as at least one phosphorus type anti-wear agent is included) is more preferable; such a combination can adsorb over the wide temperature range suitable for various operating conditions of the fan coupling. Most preferably, the phosphorus type anti-wear agent is combined with the sulfur type anti-wear agent, as clear from the examples described below. The anti-wear agent is generally used in an amount of 0.01 to 5 % by weight, preferably 0.1 to 3 % by weight of the organopolysiloxane. When the amount of the anti-wear agent is less than 0.01 % by weight, the desired effect is not obtained. On the other hand, when it is above 5 % by weight, the effect of the anti-wear agent is saturated. There is no reason to use the anti-wear agent in an amount above 5 % by weight. When the phosphorus type anti-wear agent is combined with a sulfur type anti-wear agent, it is preferably used in an amount of 5 to 95 % by weight of the total anti-wear agent. The composition may also comprise a metal deactivator. The metal deactivator preferably has at least one azo, diazo, triazo and/or thiocarbamoyl group that effectively adsorbs on the fresh metal surfaces. The metal deactivator may also preferably have in its structure one or more lone electron pairs which bond effectively to the fresh metal surfaces. Examples of the metal deactivator are benzotriazole and its derivatives, benzothiazole and its derivatives, triazole and its derivatives, dithiocarbamate and its derivatives, and indazole and its derivatives, as well as their mixture. The metal deactivator is generally used in an amount of 0.001 to 1.0 % by weight, preferably 0.01 to 0.5 % by weight of the organopolysiloxane. When the amount of the metal deactivator is less than 0.001 % by weight, the desired effect is not obtained. On the other hand, when it is above 1.0 % by weight, the resultant composition will contain a large amount of precipitates. The composition may also comprise a corrosion inhibitor. The corrosion inhibitor preferably has at least one double bond, ion binding, alkyl carboxylate and/or alkenyl carboxylate group which effectively adsorbs on any metal surface. The corrosion inhibitor effectively adsorbs on any metal surface. Examples of the corrosion inhibitor are isostearate, n-octadecylammonium stearate, diamine dioleate, lead naphthenate, sorbitan oleate, pentaerythrite oleate, oleyl sarcocine, alkylsuccinic acid, alkenylsuccinic acid and their derivatives, and their mixtures. The corrosion inhibitor is generally used in an amount of 0.001 to 1.0 % by weight, preferably 0.01 to 0.5 % by weight of the organopolysiloxane. When the amount of the metal deactivator is less than 0.001 % by weight, the desired effect is not obtained. On the other hand, when it is above 1.0 % by weight, the resultant composition will contain a large amount of precipitates. The single use of the metal deactivator or the corrosion inhibitor, together with the essential components of the composition, is effective for preventing the increase in viscosity. The combined use of the metal deactivator and the corrosion inhibitor is more preferable, as clear from the Examples described below. For furher improving the thermal stability of the composition an antioxidant is present. Examples of the antioxidant are amines such as dioctyl-diphenyl amine, phenyl-α-naphthyl amine, alkyl-diphenyl amine, N-nitroso-diphenyl amine, phenothiazine, N, N'-dinaphthyl-p-phenylene diamine, acridine, N-methylphenothiazine, N-ethyl-phenothiazine, dipyridyl amine, diphenylamine, phenolamine and 2,6-di-t-butyl-α-dimethylamino p-cresol; phenols such as 2,6-di-t-butyl p-cresol, 4,4'-methylene bis(2,6-di-t-butylphenol) and 2,6-di-t-butylphenol; organic iron salts such as iron octoate, ferrocene and iron naphthoate; organic cerium salts such as cerium naphthoate and cerium toluate; organic metal compounds such as zirconium octoate; and their mixtures. The antioxidant is generally used in an amount of 0.001 to 5 % by weight, preferably 0.01 to 2 % by weight of the organopolysiloxane. If necessary, the composition may contain any conventional additives such as an extreme pressure agent, friction modifier or colour-dye agent. Examples The present invention is now further described in the following Examples. The substances used can be prepared by any method known in the art. Example 1 To dimethylsilicone (viscosity 1000 mm²/s at 25°C), 1.0 % by weight of diphenyl amine as the antioxidant and 0, 0.5, 1.0 or 2.0 % by weight of tricresylphosphate as the phosphorus type anti-wear agent were added. 30 ml of the resultant composition was filled in a fan coupling at 25°C. The fan coupling was operated at 6500 rpm for 50 hours, after which the changes in viscosity and torque were tested. The results are shown in Table 1. amount of anti-wear agent (wt %) change in viscosity (%) change in torque (%) 2.0 0 + 1 1.0 + 3 + 3 0.5 + 5 + 7 0 not measurable not measurable Comparative Example 1 To dimethylsilicone (viscosity 1000 mm²/s at 25°C), 1.0 % by weight of 4,4'-methylene bis(2,6-di-t-butylphenol) as the antioxidant and 0, 0.5 or 1.0 % by weight of diphenyl disulfide as the sulfur type anti-wear agent were added. The resultant composition was tested as described in Example 1. The results are shown in Table 2. amount of anti-wear agent (wt %) change in viscosity (%) change in torque (%) 1.0 + 5 + 6 0.5 + 8 + 8 0 not measurable not measurable Comparative Example 2 To dimethylsilicone (viscosity 1000 mm²/s at 25°C), 0, 0.25 or 0.5 % by weight of tricresyl phosphate as the phosphorus type anti-wear agent and dibenzyl disulfide as the sulfur type anti-wear agent were added. 30 ml of the resultant composition was filled in a fan coupling at 25°C. The fan coupling was operated at 6500 rpm for 100 hours, after which the changes in viscosity and torque were tested. The results are shown in Table 3. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0.5 0 + 9 + 9 0 0.5 + 13 + 16 0.25 0.25 + 4 + 5 Example 2 A composition was prepared according to the procedure described in Comparative Example 2, but 1.0 % by weight of diphenyl amine as the antioxidant was further added. The resultant composition was tested as described in Comparative Example 2. The results are shown in Table 4. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0.5 0 + 7 + 8 0 0.5 + 10 + 12 0.25 0.25 + 5 + 6 To the above composition comprising dimethylsilicone (viscosity 1000 mm²/s at 25°C), 0.25 % by weight of tricresyl phosphate, 0.25 % by weight of dibenzyl disulfide and 1.0 % by weight of diphenyl amine, 0.20 % by weight of zinc di-sec-butyldithiophosphate as an additional sulfur type anti-wear agent was added. The resultant composition showed an increase in viscosity of + 2 % and an increase in torque of + 3 %. Example 3 A composition was prepared according to the procedure described in Example 2, but the dibenzyl disulfide was replaced with olefine sulfide as the sulfur type anti-wear agent. The resultant composition was tested as described in Example 2. The results are shown in Table 5. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0 0.5 + 8 + 8 0.25 0.25 + 5 + 5 Example 4 A composition was prepared according to the procedure described in Example 2, but the tricresyl phosphate was replaced with aminodibutyl phosphonate as the phosphorus type anti-wear agent. The resultant composition was tested as described in Example 2. The results are shown in Table 6. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0.5 0 + 8 + 5 0.25 0.25 + 3 + 4 Example 5 A composition was prepared according to the procedure described in Example 2, but the dibenzyl disulfide was replaced with zinc di-sec-butyldithiophosphate as the sulfur type anti-wear agent. The resultant composition was tested as described in Example 2. The results are shown in Table 7. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0 0.5 + 10 + 10 0.25 0.25 + 5 + 6 Example 6 A composition was prepared according to the procedure described in Example 2, but the tricresyl phosphate was replaced with triphenyl phosphorotionate as the phosphorus type anti-wear agent. The resultant composition was tested as described in Example 2. The results are shown in Table 8. amount of P-type anti-wear agent (wt %) amount of S-type anti-wear agent (wt %) change in viscosity (%) change in torque (%) 0.5 0 + 7 + 7 0.25 0.25 + 3 + 3 Comparative Example 3 To dimethylsilicone (viscosity 1000 mm²/s at 25°C), 0 or 0.5 % by weight of tricresyl phosphate as the phosphorus type anti-wear agent and 0.1 or 0.8 % by weight of benzotriazole as the metal deactivator were added. The resultant composition was tested as described in Comparative Example 2. The results are shown in Table 9. amount of anti-wear agent (wt %) amount of metal deactivator (wt %) change in viscosity (%) change in torque (%) 0 0.8 + 7 + 10 0.5 0.1 + 5 + 5 Example 7 A composition was prepared according to the procedure described in Comparative Example 3, but 1.0 % by weight of diphenyl amine as the antioxidant was added and the amount of the metal deactivator was changed. The resultant composition was tested as described in Comparative Example 3. The results are shown in Table 10. amount of anti-wear agent (wt %) amount of metal deactivator (wt %) change in viscosity (%) change in torque (%) 0 0 not measurable not measurable 0 0.1 + 15 + 15 0 0.4 + 9 + 10 0 0.8 + 5 + 6 0.5 0.1 + 4 + 4 Comparative Example 4 A composition was prepared according to the procedure described in Comparative Example 3, but the metal deactivator was replaced with n-octadecylammonium stearate as the corrosion inhibitor. The resultant composition was tested as described in Comparative Example 3. The results are shown in Table 11. amount of anti-wear agent (wt %) amount of corrosion inhibitor (wt %) change in torque (%) change in viscosity (%) 0 0.8 + 7 + 8 0.5 0.1 + 3 + 4 Example 8 A composition was prepared according to the procedure described in Comparative Example 4, but 1.0 % by weight of diphenyl amine was added as the antioxidant and the amount of the corrosion inhibitor was changed. The resultant composition was tested as described in Comparative Example 4. The results are shown in Table 12. amount of anti-wear agent (wt %) amount of corrosion inhibitor (wt %) change in viscosity (%) change in torque (%) 0 0 not measurable not measurable 0 0.1 + 16 + 16 0 0.4 + 10 + 10 0 0.8 + 6 + 8 0.5 0.1 + 4 + 4 To the above composition comprising dimethylsilicone (viscosity 1000 mm²/s at 25°C), 1.0 % by weight of diphenyl amine, 0.5 % by weight of tricresyl phosphate and 0.2 % by weight of n-octadecylammonium stearate, 0.1 % by weight of benzotriazole was added. The resultant composition showed an increase in viscosity of + 2 % and an increase in torque of + 4 %.

Claims: Use of a hydraulic, lubricating and coupling composition in a fan coupling, which composition comprises: (i) an organopolysiloxane having a viscosity of 1,000 to 20,000 cSt at 25°C; (ii) a phosphorus type anti-wear agent; and (iii) an antioxidant; said phosphorus type anti-wear agent having one of the following formulae (I) to (VII): wherein each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; each of R₅ to R₇ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms; each of X₁ to X₄ is independently oxygen or sulfur; each Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2, with the proviso that both X₂ and X₃ are sulfur when n is 0; wherein R₁ to R₇, X₁ to X₄, Y and n are as defined in formula (I); wherein each of R₁ to R₄ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; each of R₅ and R₆ is independently a divalent hydrocarbon group containing from 1 to 6 carbon atoms; each of X₁ to X₄ is independently oxygen or sulfur; each Y is independently a direct bond, oxygen or sulfur; and n is an integer of from 0 to 2; wherein each of R₁ and R₂ is independently hydrogen or a monovalent hydrocarbon group containing from 1 to 20 carbon atoms; R₈ is a hydrocarbon group containing from 1 to 20 carbon atoms and containing at least one ester bond; each of X₁ and X₂ is independently oxygen or sulfur; and each Y is independently a direct bond, oxygen or sulfur; (R-Y)₃-P=X a (V) wherein each R-Y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; Y is oxygen or sulfur; and a is 0 or 1; R (3-b) (R-Y) b -P=X a (VI) wherein each R-Y group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; Y is oxygen or sulfur; a is 0 or 1; and b is an integer of from 0 to 2; ((R)₂N) a (RO) b -P=X (VII) wherein each (R)₂N group and each RO group may be identical or different, R is hydrogen or a hydrocarbon group containing from 1 to 20 carbon atoms; X is oxygen or sulfur; a is an integer of from 1 to 3; and b is an integer of from 0 to 2, with the proviso that a+b=3 . Use according to claim 1 wherein: in formulae (I) and (II) each of R₁ and R₄ is independently hydrogen or a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group and each of R₅ to R₇ is independently a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; in formula (III) each of R₁ to R₄ is independently hydrogen or a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group and each of R₅ and R₆ is independently a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group; and in formulae (V) to (VII) each R is independently hydrogen or a linear or branched alkyl group, aryl group, aralkyl group, araryl group or halogenated hydrocarbon group. Use according to claim 1 or 2 wherein the composition also comprises a sulfur type anti-wear agent. Use according to any one of the preceding claims wherein the composition also comprises a metal deactivator. Use according to any one of the preceding claims wherein the composition also comprises a corrosion inhibitor A hydraulic, lubricating and coupling composition for use in a fan coupling which comprises: i) an organopolysiloxane having a viscosity of 1,000 to 20,000 cSt at 25°C; ii) a phosphorus type anti-wear agent as defined in claim 1 or 2; iii) an antioxidant; and iv) a sulfur type anti-wear agent, metal deactivator or corrosion inhibitor. A fan coupling which comprises a composition as defined in any one of claims 1 to 5.

Inventors: OHENOKI HITOSHI TONEN CORP, TOMIZAWA HIROTAKA TONEN CORP, UMEMOTO NOBORU TONEN CORP, OHENOKI, HITOSHI TONEN CORP., TOMIZAWA, HIROTAKA, TONEN CORP., UMEMOTO, NOBORU, TONEN CORP.
Applicants: TONEN CORP, TONEN CORPORATION
Application year: 1991
Main classification: C10M169
IPC codes: C10M169