CA1143722A - Oil for mechanical power transmission - Google Patents

Abstract

APPLICATION FOR LETTERS PATENT FOR
COMPOSITION SUITABLE FOR MECHANICAL POWER
TRANSMISSION AND PROCESS FOR OPERATING TRACTION DRIVES

ABSTRACT OF THE DISCLOSURE
The disclosure relates to a composition suitable for use in mechanical power transmission devices. It has as its prin-cipal component a hydrocarbon oil which has from 19 to 30 carbon atoms, inclusive, and three six-membered carbocyclic rings and consists of a mixture of compounds having the following formula:

(I) wherein R1 is a divalent straight or branched chain radical CyH2y where y is an integer of l through 3; R2 is a straight chain radical CzH2z where z is an integer of l through 3; R3, R4, and R5 are the same or different alkyl groups having from 1 through 4 carbon atoms; ? , m, and n each is an integer from zero through 3; and x is zero or 1; and wherein rings A and B
are hydrogenated benzene rings and ring C is a hydrogenated benzene ring when X is 1 and a hydrogenated benzene ring or a cyclohexane ring when X is zero said hydrogenated benzene rings being saturated with hydrogen to the extent of at least 80% but less than 100% of the theoretical, and the composition can additionally contain one or more of an antioxidant, a rustproof-ing agent, a viscosity index improver, and antifoaming agent.
INVENTORS:
Yoshiharu Horita 7-17, Toyotamanaka 3-chome, Nerima-ku, Tokyo, Japan Kenichi Fujimoto 3880-2, Hisage, Kanda-machi, Miyako-gun, Fukuoka-Ken, Japan Michio Hoshino 4207-752, Takeyama, Midori-ku, Yokohama-shi, Kanagawa-ken, Japan Tetsuo Takito 3-6, Shimoshinjo, Nakahara-ku, Kawasaki-shi, Kanagawa-ken, Japan Masayoshi Muraki Nobadanchi 3-3310, 618, Nobacho, Konan-ku, Yokohama-shi, Kanagawa-ken, Japan

Description

'~.
COMPOSITION st3IT~sLE FOI~ MEC~l~NICAL POI~E~
TRANSMISSION AND PROCESS FOR O~E~ATING TRACTION DRIVES

BACKG~OUND OF TH~ INVEMTION
Field of the Inventlon This invention relates to a composition suitable for use in mechanical power transmission units. More particularly, the invention relates to compositions specifically adapted for use with traction drives and to a process for operating traction drives.

Prior Art Heretofore, gears and hydraulic devices have been used for power transmission or speed control. A system of drives, called traction drives (rolling friction drive devices), which resort to point contact or line contact between rolling solid bodies has found recognition. These traction drives are particularly useful in industrial machines because they provide high power transmission efficiency without the vibration characteristic of devices using gears and like positive forms of engagement.
As the fluid to be interposed between contact parts of such traction drives, there must be selected a lubricant which proves most suitable from the functional point of view. Specifically, the fluid intervening between contact parts is required to possess an ability to undergo reversible glass transition, vis-cosity increasing, and enhance the efficiency of power trans-mission between surfaces of rolling contact under high pressure and, on departure from such contact surfaces, immediately return to its original fluid state. It must also be capable of pre-cluding direct contact between metal bodies, preventing metal bodies from seizure, wear and fatigue damage and, similarly to lubricants of all kinds fulfilling important functions of pre-_ 1 _ "';~' HATT~-29 ~3~ Z

venting occurrence of rust and elevation of temperature.
E`riction or traction drive devices for transmission of mechanical power have been disclosed in a number of reports in prior technical literature. They are dealt with in full detail in US Patents 3,394,603 and 3,411,369; the Journal of Chemical and Engineering Data, Vol. 5, No. 4, p.p. 499-507 (1960), and Hewko et al., in Proceedings of the Symposium on ~olling Contact Phenomena, p.p. 157-185 (1962), Elsevier, Amsterdam, Netherlands, for example.
As compositions for use in traction drives, a host of substances have been advanced, including mineral oils (Japan-ese Patent Publication 24,635/1964), mixtures of dialkyl aro-matic hydrocarbons with diarylalkanes (Japanese Patent Publica-tion 40,525/1972), polymethylmethacrylate (Japanese Patent Publication 31,828/1973), adamantanes (Japanese Patent Publica-tions 42,067/1973 and 42,068/1973), polyolefins (Japanese Patents KOKAI 4,766/1971 and 2,229/1972) and alkylnaphthalenes (US
Patent 2,549,377), for example. Japanese Patent KOKAI 40,726/
1980 has proposed fluids which are obtained by hydrogenating bis-(q-methylbenzyltoluene) and/or bis-(~-methylbenzyl)-xylene.
Besides, proposals abound which concern naphthenic oils having naphthenic rings. These naphthenic oils include di-- cyclohexylethane (US Patent 3,577,361), dicyclohexylpropane (Japanese Patent Publication 36,105/1978), hydrogenated condensa-tion ring compounds (US Patent 3,411,369), naphthenes containing at least one saturated carbon-containing cyclic ring (US Patent 3,440,894), naphthenes containing at least two saturated carbon-containing cyclic rings (US Patent 3,925,217), and mixtures o~
naphthenes and paraffins ~US Patents 3,595,796 and 3,595,797), and an oil which is obtained by hydrogenating the product of alkylation of xylene and/or toluene with styrene (Japanese ~ HATTA-29 Z

Patent KOK~I 43,108/1980), for example.
US Patents 3,4~0,894 and 3,925,217 mentioned above embrace a wide range of naphthenic compounds and cite a large number of naphthenes by way of example. Most of them are compounds which possess one or two hydrogenated rings. Among the compounds dis-closed therein, those which possess three or more hydrogenated rings are limited to a small number, including tercyclohexyls 1,2,3-tricyclohexylpropane and tricyclohexylmethane, for ex-ample. Although they have a high traction factor, they have poor practical use because of high viscosity or high crystal-precipitating temperature. It is noted from the p~ior te~hnical literature that naphthenic oils containing hydrogenated -ings are possessed of generally outstanding properties for lubric-ants, particularly those to be used in traction drives.
OBJECTS OF THE INVENTION
An object of this invention, therefore, is to provide novel compositions suitable for use in mechanical power transmission devices. Another object of the invention is to provide such compositions which excel in traction properties and other pro-perties such as resistance to oxidation and resistance to corro-sion and which are easily synthesized from inexpensive raw materials on a commercial scale. Still another object is to provide a novel process for operating traction drives. Other objects are to avoid the disadvantages of the prior art and to obtain such advantages as will appear as the description proceeds.
SUMMARY OF THE INVENTION
The objects described above are accomplished by provision of a composition suitable for use in mechanical power trans-mission units, consisting essentially of a minor amount of an antioxidant in admixture with a hydrocarbon oil which has from HAT~rA-29 ~;3'7~Z

19 through 30 carbon atoms and three six-membered carbocyclic rings and consists of a mixture of compounds having the follow-ing formula: (R3) (R4) (R5)n ~ ~ _ Rl ~ (R )x ~ (I) wherein R1 is a divalent straiyht or branched.chain radical CyH2y where y is an integer of l through 3; R2 is a straight chain radical CzH2z where z is an integer of l through 3; R3, R4, and R5 are the same or different alkyl groups having from 1 through 4 carbon atoms; Q, m, and n each is an integer from zero through 3; and x is zero or 1; and wherein rings A and B
are hydrogenated benzene rings and ring C is a hydrogenated benzene ring when X is 1 and a hydrogenated benzene ring or a cyclohexane ring when X is æero said hydrogenated benzene rings being saturated with hydrogen to the extent of at least 80% but less than 100% of the theoretical and said hydrocarbon oil being otherwise unsaturated. Advantageously, the rings are saturated to at least 95%.
In one form of the invention it is preferred that X in the formula is 1; in another, that it is zero. Preferred com-pounas in such cases include hydrogenated 1-(benzylphenyl)-1-phenylethane having from zero to two, inclusive, methyl sub-stituents and from zero to two, inclusive, ethyl substituents;
hydrogenated dibenzylbenzene having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents; hydrogenated benzylbiphenyl having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents; and, hydrogenated 1-biphenyl-1-phenylethane having from zero to two, inclusive, methyl sub-29 stituents and from zero to two~ inclusive, ethyl substituents.

3, 72Z

~ dvantageously, the composition contains additionally up to 100 parts, preferably 10 to 60 parts, of an alkylcyclohexane in which the alkyl group contains from 9 through 20 carbon atoms for each 100 parts of said hydrocarbons.
The invention also relates to a process for operating traction drives which have an area of point or line contact between rolling solid bodies in which the area of contact is oiled with the above composition.
Thus, it has been found that a mixture of hydrocarbons having a backbone wherein three hydrogenated benzene rings are linearly linked through the medium of two chains, CyH2y and CzH2z, or two hydrogenated benzene rings are linearly linked directly by a CyH2y group and a hydrogenated benzene or cyclohex-ane ring is linked to one of them without any intervening chain, because of its peculiar molecular structure, is specifically effective in fulfilling the objects of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The principal component of the hydrocarbon oil of this in-vention for use in mechanical power transmission devices is a naphthenic-type hydrocarbon compound having 19 to 30 carbon atoms, inclusive, and three hydrocarbon benzene rings and is represented by the aforementioned general formula I, wherein y and z in R1 and R2 severally are 1, 2, or 3, preferably y is 1 or 2 and z l, R3, R4, and R5 severally are alkyl groups having 1 to 4 carbon atoms, inclusive, preferably 1 or 2 carbon atoms, ~, m, and n severally are zero, 1, 2, 3, or desirably, zero, l,

2, or 3 and preferably, zero, 1 or 2, and X is either zero or 1.
Where X is 1, therefore, the compound of the general form-ula I can be expressed by the general formula II. Where X is zero, therefore, this compound can be expressed by the general formula III.

,3l~Z2 (R3)R (n4)m (R5)n ~l ~ R2 ~ (II) (R3)R (~4)m (R5)n ~ Rl ~ ~ ) (III) wherein R1, R2, R3, R4, R5, ~, m and n have the same meanings as defined above and ring C in formula III is a hydrogenated benzene or a cyclohexane ring.
Where X is 1, the compounds represented hy the general formula I include hydrogenated dibenzylbenzenes, hydrogenated (methylbenzyl)-benzylbenzenes, hydrogenated (dimethylbenzyl)-benzylbenzenes, hydrogenated di-(methylbenzyl)benzenes, hydrogen-ated (ethylbenzyl)-benzylbenzenes, hydrogenated di~(ethylbenzyl)-benzenes, hydrogenated (diethylbenzyl)-benzylbenzene~, hydrogen-ated dibenzyltoluenes, hydrogenated dibenzyl-dimethylbenzenes, hydrogenated dibenzyl-ethylbenzenes, hydrogenated (methylben-zyl)-benzyltoluenes, hydrogenated (dimethylbenzyl)-benzyltolu-enes, hydrogenated (ethylbenzyl)-benzyltoluenes, hydrogenated di-(methylbenzy~toluenes, hydrogenated di-(ethylbenzyl)toluenes, hydrogenated di-(methylbenzyl)xylenes, hydrogenated 1,1-(benzyl-phenyl)-phenylethanes, hydrogenated 1,1-[(methylbenzyl)-phenyl]-phenylethanes, hydrogenated 1,1-(benzylphenylj(methylphenyl)-~0 ethanes, hydrogenated 1,1-(benzylmethylphenyl)-phenylethanes, hydrogenated 1,1-(benzylphenyl)(ethylphenyl)ethanes, hydrogen-ated 1,1-(benzylethylphenyl) phenylethanes, hydrogenated phen-ethyl-benzylbenzenes, hydrogenated phenethyl-benzyltoluenes, hydrogenated diphenethylbenzenes, and hydrogenated diphenethyl-toluenes, for example.

37~;2 Among the compounds represented by the general formula II
mentioned above, hydrogenated dibenzylbenzenes and hydrogenated (benzylphenyl)-phenylethanes or the derivatives thereof incor-porating one to two methyl or ethyl substituents, particularly hydrogenated dibenzyltoluenes, are especial.ly suitable for the objects of the present invention.
Where X is 0, the compounds represented by the general formula I mentioned above include hydrogenated benzylbiphenyls, hydrogenated benzy~monomethyl-biphenyls, hydrogenated benzyl-dimethyl-biphenyls, hydrogenated benzyl-trimethyl-biphenyls, hydrogenated benzyl-monoethyl-biphenyls, hydrogenated .~benzyl-diethyl-biphenyls, hydrogenated benzyl-triethyl-biphenyls, hy-drogenated biphenylyltolyl-methanes, hydrogenated (methyl-bi-phenylyl)tolyl-methanes, hydrogenated ~dimethylbiphenylyl)tolyl-methanes, hydrogenated (trimethylbiphenylyl)tolyl-methanes, (ethylbiphenylyl)tolyl-methanes, hydrogenated (diethylbiphen-ylyl)tolyl-methanes, hydrogenated (biphenylyl)(ethylphenyl)-ethanes, hydrogenated (methylbiphenylyl)(ethylphenyl)-methanes, hydrogenated (dimethyl-biphenylyl)(ethylphenyl)-methanes, hy-drogenated (trimethylbiphenylyl)(ethylphenyl)-methanes, hydro-genated (ethylbiphenylyl)(ethylphenyl)-methanes, hydrogenated (diethylbiphenylyl)(ethylphenyl)-methanes, hydrogenated 1-bi-phenylyl-1-phenyl-ethanes, hydrogenated 1-(methylbiphenylyl~-i-phenylethanes, hydrogenated 1-(dimethylbiphenylyl)-l-phenyl-ethanes, hydrogenated 1-(ethylbiphenylyl)-1-phenylethanes, hy-drogenated 1-(diethylbiphenylyl)-1-phenylethanes, hydrogenated 1-biphenylyl-1-(methylphenyl)ethanes, hydrogenated 1-(ethylbi-phenylyl)-1-(methylphenyl)ethanes, hydrogenated 1-(methylbi-phenylyl)-1-(methylphenyl)ethanes, hydrogenated 1-biphenylyl-1-30 (ethylphenyl)ethanes, hydrogenated 1-(methylbiphenylyl}1 (ethyl-phenyl)ethanes, hydrogenated 1-(dimethylbiphenylyl)-1-(ethyl-~3 ~ HATTA-29 phenyl)ethanes, hydrogenated 1-(ethylbiphenylyl)-1-(ethyl-phenyl)ethanes, hydrogenated phenethylbiphenyls, hydrogenated phenethyl-methylbiphenyls, hydrogenated phenethyl-dimethylbi-phenyls, hydrogenated phenethyl-ethylbiphenyls, hydrogenated phenethyl-diethylbiphenyls, hydrogenated (methylphenethyl)bi-phenyls, hydrogenated (methylphenethyl)-methylbiphenyls, hydro-genated ~methylphenethyl)-ethylbiphenyls, and hydrogenated (ethylphenethyl)biphenyls, for example.
Among the compounds which are represented by the general formula III mentioned above, hydrogenated benzylbiphenyls or derivatives thereof incorporating one or two methyl or ethyl ( substituents are particularly suitable for the objects of this invention.
The compound of the general formula II such as, for ex-ample, hydrogenated dibenzylbenzenes are obtained by hydrogen-ating dibenzylbenzene resulting from the reaction of benzyl halides and benzene in the presence of a Friedel-Crafts cata-lyst. Among other benzyl halides, benzyl chloride proves ad~an-tageously useful. Advantageously, the benzyl halides are used in an amount of not more than 1 mol, preferably in the range of from 0.1 to 0.5 mol per mol of benzene. Among other compounds usable as Friedel-Crafts catalysts, sulfuric acid, boron tri-fluoride and aluminum chloride prove particularly suitable, with aluminum chloride as the best choice. The amount of aluminum chloride to be used is desired to fall in the range of from 0.0001 to 0.1 mol, per mol of benzyl chloride. Although the reaction temperature can be selected in the range of from 20 to 150C, it is preferably cho~en from the range of from 40 to 80C. Although the reaction pressure has only to exceed the minimum level required for maintaining the contents of the reactor in a liquid phase, the pressure in the range of from 0 I~TTA-29

3~ 2 to 10 kg/cm2G proves advantageous for the sake of the reaction.
This reaction affords as its product dibenzylbenzene which is a mixture of ortho, meta and para isomers. These isomers may be subjected to hydrogenation in their mixed form or in their sepa-rated form. Preparatory to the hydrogenation, the Friedel-Crafts catalyst is removed from the reaction mixture as by wash-ing with water and the unreacted portions of reactants and possibly by-products of reaction are expelled from the reaction mixture as by distillation to isolate dibenzylbenzene. Then, the isolated reaction product is treated in the presence of a hydrogenation catalyst to undergo hydrogenation.
As the hydro~enation catalyst, a platinum, palladium, rhod-ium,ruthenium or nickel catalyst functions advantageously. The nickel catalyst is used in an amount within the range of from 0.1 to 20 weight percent. The hydrogen pressure is suitable in the range of from 10 to 200 kg/cm2G. The hydrogen for the hydrogenation is used in an amount of 9 mols or more per mol of dibenzylbenzene, preferably 1.1 times the mol ratio metioned above. The reaction temperature of hydrogenation is in the range of from 100 to 200C, preferably from 140 to 170C.
When the hydrogenation has proceeded to a predetermined ratio of hydrogenation, the reaction is stopped and followed by isolation of hydrogenated dibenzylbenzene. This isolation of the reaction product may be obtained by simply removing the used catalyst.
It may be effected by separation through filtration or option-ally by any of ordinary methods adopted for treatment of lubri-cants such as, for example, treatment with activated clay. When necessary, distillation may be adopted for this purpose. Little advantage, however, is usually derived from the distillation - 30 unless the reaction has produced low boiling compounds as by-products because, by distillation, separation of fully hydrogen-3~7~Z

ated dibenzylbenzene and partially hydrogenated dibenzylbenzene or separation of isomers is obtained only with great difficulty.
Production of an alkyl-substituted hydrogenated dibenzyl-benzene is accomplished by substituting benzene or benzyl hal-ides or both respectively with an alkyl-substituted benzene or alkyl-substituted benzyl halides or both as the raw materials and using these raw materials in suitable combinations. Suit-able alkyl-substituted benzenes for this purpose are toluene, ethylbenzene, propylbenzene, xylene, cumene, diethylbenzene, and methylethylbenzene. Suitable alkyl-substituted benzyl halides for the purpose include derivatives of benzyl halides incorporating monomethyl or monoethyl substituents. When such alkyl-substituted raw materials are adopted, the reaction can be carried out under similar conditions as described above and the hydrogenation can be performed similarly.
When a compound represented by the general formula:

(R3)~
~ CH2 -- CH2 X (wherein, R3 and ~ have the same meanings as defined above and X stands for a halogen) is used in the place of the aforementioned benzyl halides or an alkyl-substituted derivative thereof, there can be obtained hydrogenated diphen-ethyl benzene or an alkyl-substituted derivative thereof.
In a preferred embodiment of the method for the manufacture of the compounds of this invention, a hydrogenated (benzylphenyl)-phenyl alkane-type compound is obtained by reacting a diphenyl alkane with benzyl halides in the presence of a Friedel-Crafts catalyst to afford a (benzylphenyl)-phenyl alkane and subsequ-ently hydrogenating this reaction product. In this case, when a 1,1-diphenyl alkane is used as the diphenyl alkane, there is produced a hydrogenated 1-(benzylphenyl)-1-phenyl alkane-type compound. Use of an alkyl-substituted 1,1-diphenyl alkane or an H~TlA-29 ~3~;~2 alkyl-substituted benzyl halide or both results in production of a hydrogenated alkyl-substi~uted l-(benzylphenyl)-1-phenyl alkane-type compound. When a 1,3-diphenyl alkane is used as the diphenyl alkane, there is obtained a hydrogenated 1-(benzylphen-yl)-3-phenyl alkane-type compound and when a 1,2-diphenyl alkane is used, there is obtained a 1-benzylphenyl-2-phenyl alkane or a 2-benzylphenyl-1-phenyl alkane. In all these cases, the kind of the Friedel-Crafts catalyst, the conditions of the Friedel-Crafts reaction of alkyl halides, the conditions of the hydro-genation, etc., are similar to those described above. The aforementioned 1,1-diphenyl alkanes can be obtained by the re-action of ethylbenzene or styrene and benzene in the presence of the Friedel-Crafts catalyst.
The compounds of the general formula III such as, for ex-ample, hydrogenated benzylbiphenyl are obtained, similarly to those of the general formula II, by hydrogenating benzylbi-phenyls resulting from the reaction of benzyl halides with bi-phenyls in the presence of the Friedel-Crafts catalyst. In this case, the amount of aluminum chloride to be used is desired to fall in the range of from 0.0001 to 0.05 mol per mol of benzyl chloride. Although the reaction temperature can be selected in the range from a level exceeding the melting point of the bi-phenyls involved to 180C, it is preferably selected in the range of from 70 to 100C. Although the reaction pressure has only to exceed the minimum level required for maintaining ~` the contents of the reactor in a liquid phase, it is preferred to fall in the range of from 0 to 50 kg/cm2G. This reaction affords as its product benzylbiphenyl, which is a mixture of ortho, meta and para isomers. These isomers may be subjected to hydrogenation either in their mixed form or in their separated form. Preparatory to the hydrogenation, the reaction mixture is 3~7'~
washed with water and distilled to effect removal of the unre-acted reactants and the used Friedel-Crafts catalyst and isola-tion of benzylbiphenyl. The isolated benzylbiphenyl is then hydrogenated by introduction of hydrogen in the presence of a hydrogenation catalyst. In l-his casei the conditions for the hydrogenation are the~same as those adopted in the hydrogenation for the production of the compounds of generai formula II.
Production of a hydrogenated alkyl-substituted benzylbi-phenyl is accomplished by substituting a biphenyl or a benzyl 10halide or both respectively with an alkyl-substituted biphenyl or an alkyl-substituted benzyl halide or both as the raw mater-ials by using these raw materials in suitable combinations.
Suitable alkyl-substituted biphenyls are monomethylbiphenyl, monoethylbiphenyl, monopropylbiphenyl, dimethylbiphenyl, di-ethylbiphenyl, and methylethylbiphenyl. And suitable alkyl-sub-stituted benzyl halides are derivatives of benzyl halides in-corporating monomethyl, monoethyl and other similar substitu-ents. When these alkyl-substituted derivatives are used, the reaction can be carried out under similar conditions, as de-20scribed above. The hydrogenation can also be performed simi-larly.

When a compound represented by the general formula:
(R3)~
~ CH2 -- CH2X (wherein R3 and ~ have the same meanings as defined above and X stands for a halogen) is used in the place of the aforementioned benzyl halides or an alkyl-substituted derivative thereof, there can be obtained hydrogenated phen-ethylbiphenyl or an alkyl-substituted derivative thereof.
Another preferred embodiment of the method for the manufac-ture of the compound of this invention comprises the steps of 30reacting cyclohexylbenzene or a biphenyl with styrene in the presence of the Friedel--Crafts catalyst and hydrogenating the ilATTA-29 ~..1'~3t7'~2 resultant reaction product. Suitable Friedel-Crafts catalysts for this reaction are boron trifluoride, aluminum chloride and sulfuric acid. When sulfuric acid is adopted as the catalyst, the amount of this catalyst is desired to fall in the range of from 5 to 50 weight percent based on the amount of the biphenyl involved. The cyclohexylbenzene or biphenyl and styrene are preferably used in equal or nearly equal mol proportions in order to preclude the otherwise possible polymerization of styrene in the reaction. The reaction temperature is desired to be low, falling on the order of from 0 to 30C. When the reaction is terminated, the reaction mixture is washed with water to effect removal of the used catalyst and then dis-tilled to effect isolation of 1-(biphenylyl)-1-phenylethane or 1-(cyclohexylphenyl)-1-phenylethane as the reaction product.
The compound, when subjected to hydrogenation by the same method as described above, produces hydrogenated 1-(biphen-ylyl)-1-phenylethane.
When a similar procedure is repeated by using an alkyl-substituted cyclohexylbenzene or an alkyl-substituted biphenyl or an alkyl-substituted styrene respectively in the place of cyclohexylbenzene or biphenyl or styrene, there is obtained an alkyl-substituted hydrogenated 1,-(biphenylyl)-1-phenylethane.
Alkyl-substituted cyclohexyl benzenes suitably usable for the purpose are cyclohexylmethylbenzenes, cyclohexyl-ethylbenzenes, cyclohexyl-propylbenzenes, cyclohexyl-dimethylbenzenes, cyclo-hexyl-diethylbenzenes, ~methylcyclohexyl)benzenes, (dimethyl-cyclohexyl)benzenes, (ethylcyclohexyl)benzenes, (diethyl-cyclo-hexyl)benzenes, and mixtures thereof. Alkyl substituted bi-phenyls suitably useful herein are the same as those cited above. Suitable alkyl-substituted styrenes include those com-pounds represented by the general formula: C~2=CH ~ (R3)~

(wherein R3 and ~ have the same meanings).

~143~7'~Z
A typical example of these compounds is vinyl toluene. Also, ~-methylstyrene can be used similarly with advantage. When these alkyl-substituted derivatives are utilized, the reaction can be carried out under similar conditions as described above.
The composition of the present invention for use in mech-anical power transmis~ion devices can be used in its independent form. ~hen it is mixed with an alkyl(Cg-C20) cyclohexane added thereto in an amount of at most 100 parts by weight, preferably in the range of from 10 to 60 parts by weight, based on 100 parts by weight of the compound of this invention, there can be obtained a composition possessed of a varying degree of vis-cosity useful in mechanical power transmission devices without substantially degrading the properties which the oil is expected to possess to fulfill its function~ Alkyl cyclohexanes suitable for this purpose are obtained by hydro~enating alkylbenzenes derived by the reaction of trimer through pentamer of propylene with benzene.
The compositions of the invention can contain, in addition to its essential ingredients, namely, a minor amount of an anti-oxidant and a hydrocarbon oil as above described, can contain other additives or by-products as long as they do not detract from its suitability for use in mechanical power transmission.
Thus, in addition to antioxidants, the compositions can contain such additives as rustproofing agents, antifoam agents, and the like. They also can include a small amount of the by-pro-ducts which occur in the course of the production of the hydro-carbon oils represented by the general formula I. However, a large amount of aromatic hydrocarbons or compounds possessing a double bond are desirably avoided. In the production of a compound represented by the general formula I by the hydrogena-tion of a corresponding aromatic hydrocarbon, therefore, the I~A'I'TA- 2 9 ,1 1ilL3 ;~

hydrogenation is desired to be performed until the hydrogenation reaches at least 80~ of completion, desirably 95% and preferably more than 95%. Substantially complete hydrogenation, e.g., re-moval to less than 1% is practically impossible. Such complete removal of unsaturation, however, is not called for, because the objects of this invention are not obstructed b~ the presence of unsaturated compounds in small amounts. Thusl the hydro-carbon oils which constitute the essential components of the compositions of the invention are mixtures of components in different stages of hydrogenation or isomers or both and can be ; used as such or in combination with suitable additives, as mentioned above.
The reference to hydrogenated compounds, accordingly, is to be understood to include such compounds which have been hydrogenated to at least 80%, preferably to at least 95~, of the theoretical.
The traction coefficient of a given oil is generally measured by use of a traction drive device. In the present invention, the measurement has been made by use of a Soda's four roller machine friction tester. (T. Kimura and M. Muraki "TRI~OLOGY",1979 (12), p. 255). In this tester, traction (roll-ing friction) occurs at the three areas of contact formed be-tween an inner centrally located roller and three outer rollers tangentially located around the inner central roller. These rollers are arranged so that equal perpendicular loads are caused to bear on the three areas of contact. The surface pressure of contact as expressed by the average Hertzian press-ure falls in the range of from 0.575 to 1.157 GPa. The other conditions for the determinaton of traction by this tester are as shown in Table 1 below.

H F~T'I'A - 2 9 37'~2 Table 1. Conditions for determination of traction Speed of rotation 1.05 to ~.19 m/sec Speed of sliding 0 to 0.22 m/sec Test rollers Material bearing steel, SUJ-2 ~ardness (Hv) 760 to 800 Dimensions 40mm x 9mm (outer rollers) (diam x width~ 40mm x 5mm (central roller) Method of lubrication--Dripping about 10 ml/min in flow volume Feed oil temperature 28C
The procedure of the test comprised first setting the central and outer rollers rotating at a fixed speed, applying a load to bear upon these rollers and thereafter accelerating the rotational speeds of the outer rollers while keeping that of the central roller constant thereby inducing slide/roll ratios to permit continuous measurement of the change in the friction torque or the traction coefficient. The friction torque was determined by directly measuring the torsional moment of the centerlessly-supported shaft of the central roller with a re-sistance-wire strain meter.
The traction coefficient determined under the conditions mentioned above tends first to rise in a straight line with the increasing slide/roll ratios, then reach a peak and start fall-ing. Of the curve thus drawn, the important zone from the standpoint of the practical use of oil falls in the first por-tion of straight line in which the magnitude of heat generated by the shearing of the oil film is not large. Thus, the trac-tion coefficient specifically within this zone will be con-sidered exclusively herein below.
Under the test conditions of 1.157 GPa of average Hertzian pressure and 4.19 m/s of rotational speed, for example, the following ~raction coefficients were obtained.

37"~ ~

vi~cosity(cst) tractlon at 40C conefficient Naphthenic mlneral oil 8.0 0.050 Hydrogenated Polyisobutylene 10.0 0.060 Dicyclohexane 2.9 0.065 Ethyl Dicyclohexane 4.0 0.060 Methylcyclohe~yl Cyclohe~ylmethane 4.2 0.065 Dicyclohexylethane 4.0 0.070 sec-Dodecylcyclohe~ane 5.4 0.050 ~ercyclohexyls(o-and m-mi~ture)* 30 0.090 Hydrogenated ~-Methylstyrene linear dimer 22 0.~90 * crystal was precipitated at room temperature.
In contrast, the traction coef~icient of the compound obtained by the pre~ent invention reached as high as 0.095, a value definitely higher than the values ~ound for the afore-mentioned hydrocarbon~. It ha3 been found con~eguently that the product of this in~ention even excels hydrogenated d-methyl-styrene linear dimer, which i9 now marketed as a Ibest' ~ynthetic traction fluid.
In sddition to traction coefficient and oxidation stubility, the composition for mechanical power tran~mission i~ required at least -10C of pour point or freezing point and i8 preferred 7-150 cst of ~iscosity at 40C under atmospheric pressure.
vi~co~ity(cst) pour point or at 40C freezing point(~C) o tercyclohexyl - 45 m-tercyclohexyl - 63 p-tercyclohexyl - 162 m-, p-tercyclohe~yls mi~ture 30 crystal was precipitated at room temperature tricyclohexymethane - 59 1,1,3-tricyclohexyl propane about 2500 As being clear from abo~e, the above-mentioned compound~ are 3~7~Z

not sppropriate as a base oil for the compo~ition for mechanical power transmi~sion.
Further, in order to ~ecure stable operation of a traction device for a long time, the composition for mechanical power transmi~sion i~ required good ~ealing properties. Following table shows the sealing propertie~ of the composition for mechanical power transmis~ion using base oil3 having appropriate viscosity as the composition and relatively good traction property.
The tests were carried out at 120C for 70 hours about nitrile rubber (~una N) and acrylic rubber ba~ed on a method of JIS K-6301.

Ba~e oil E~ample 1 and 4 _*
Rubber Nitrile Acrylic Nitrile Acrylic rubber rubber rubber rubber Propert~ (Buna N) (Buna N~
Increase of weight(%) 3.45 1.48 7.30 3.86 Increa~e of volume(%) 6.58 3.42 13.6 7.67 Tensile strength(~gf/cm2) 195 81 168 85 Elongation(%) 260 140 150 110 Variation of hardness(%) -6 0 ~6 -1 Aniline point 85C 70C
The oil in accordance with the present invention can be used in itself, but addition of the additives is a pre~erable embodiment.
In sddition to the traction characteristics described above, the oil for use in traction drives needs to possess propertie~
usually e~pected of ordinary lubricant~ such a~, for e~ample, o~idation stability, resistance to the corrosive action of a vi~cosity inde~ improver~ resistance to wear, rustproofne~, rubber swelling property, and ability to prevent foaming. Thus, ~0 depending on the nature of use, ~uitable additives, for e~ample, 2,6-di tertiary-butyl-para-cresol and other ~imilar alkyl phenols, -17a-* Hydroyenated ~ -methylstyrene dimer oil for traction drives '7~Z
zinc dialkyl-dithiopho3phate and other 3imilar sulfur-phosphorous compound~ can be incorporated aB antio~idants; amine~, esters and metal salts as rustproofing agent~; polymethacrylate~ a~ viscoslty inde~ improvers; and ffiliconetype polymers a~ antifoaming agent~, can be included.
Now, the present invention will be described more ~pecifically below with reference to working examples. Wherever "parts" or "percentages" are mentioned in the ~ollowing ex--17b-IIATT~-29 ~3~ Z
amples, and elsewhere herein, they are by weight unless other-wise specified.
In the following examples, a composition suitable for use in traction drives was prepared by adding to the hydrogenated dibenzyltoluene, or like oil, according to the invention, 2,6-di-tertiary-butyl-para-cresol and zinc dialkyl-dithiophosphate as antioxidants, each in the amount of 0.5 weight percent. This oil was tested for traction coefficient under the aforementioned conditions and then subjected to an oxidation test by the pro-cedure described in Paragraph 3.2 (Testing Method for Oxidation Stability of Internal Combustion Engine ~il of Japanese Indus-trial Standard (JIS) K-2514-1980 (Testing Method for Oxidation Stability of Lubricating Oils).
Example 1 To 3 parts of toluene was added 0.002 to 0.01 part of aluminum chloride. The mixture was heated to 70C and then allowed to react with 1 part of benzyl chloride added thereto for two hours. The reaction mixture was washed with water to remove the used catalyst and then distilled to expel the un~
reacted portion of reactants. The dibenzyltoluene (mixture of isomers) thus obtained was supplied to an autoclave and, in the presence of a nickel catalyst, subjected to hydrogenation for four hours under the conditions of 40 kg~cm2G of initial hy-drogen pressure and 200C of temperature, to afford hydrogen-ated dibenzyltoluene (mixture of isomers). The general attri-butes of this hydrogenated dibenzyltoluene were as shown in Table 2. The results of the oxidation test were as shown in Table 3. For the purpose of comparison, a commercially avail-able hydrogenated d-methylstyrene linear dimer-type oil for traction drives and an oil prepared from a naphthenic mineral oil were subjected to the same tests.

~37~
1`he oxidation test was carried out under the following conditions.
Amount of test specimen 300 ml Temperature 165.5C
Time 72 hours Oxidation catalyst Copper and iron Example 2 To 4 mols of 1,1-diphenylethane was added 0.001 to 0.005 mol of aluminum chloride. The mixture was heated to 60C and allowed to react upon 1 mol of benzyl chloride added thereto for 20 minutes. Then, the reaction mixture was washed with water to remove the used catalyst and subsequently distilled to expel the unreacted portions of the reactants. The isolated 1-(benzyl-phenyl-1-phenylethane (mixture of isomers) was supplied to an autoclave and, in the presence of a nickel catalyst, subjected to hydrogenation under the conditions of 100 kg/cm2G of ini-tial hydrogen pressure, 140 to 170C of temperature for five hours, to afford hydrogenated 1-(benzylphenyl)-1-phenylethane (mixture of isomers). The general attributes of this reaction product were as shown in Table 2.
This product, compounded as above, was tested for traction coefficient and subjected to the oxidation test, as specified in Paragraph 3.2 of JIS K-2514-1980. The results were shown in Table 3.
Example 3 A hydrogenated monoethyl-substituted l-(benzylphenyl)-1-phenylethane, a mixture of compounds of the formulas ~ - CH- ~ CH2 ~ a~ ~ Cll ~ Cllz ~

29 was obtained by following the procedure of Example 2, except 3~7;~,~ HI~TT~-29 that 4 mols of monoethyl-substituted 1,1-diphenylethane was used in the place of 1,1-diphenylethane. The general attri-butes of this reaction product were as shown in Table 2. This product, compounded as above, was tested for traction coeffic-ient and subjected to the oxidation test specified in Paragraph 3.2 of JIS ~-2514-1980. The results were as shown in Table 3.

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EXAMPLF` 4 J
To 5 parts of biphenyl was added 0.001 to 0.005 part of aluminum chloride. The mixture was heated to 70C and then allowed to react upon 1 part of benzyl chloride added thereto for 20 minutes. The reaction mixture was washed with water to remove the used catalyst and then distilled to expel the unre-acted fractions of the reactants. The produced ~enzylbiphenyl (a mixture of isomers) was supplied to an autoclave having an inner volume of 1 liter and, in the presence of a nickel cata-lyst, subjected to hydrogenation under the conditions of 100 kg/cm2G of initial hydrogen pressure and 140 to 170C tempera-ture for two hours, to afford hydrogenated benzylbiphenyl (a mixture of isomers). The general attributes of this hydrogen-ated benzylbiphenyl were as shown in Table 4.
This product, compounded as described above with 0.5 weight percent each of 2,6-di-tertiary-butyl-para-cresol and zinc dialkyl-dithiophosphate as antioxidants, was tested for traction coefficient and subjected to the oxidation test as specified in Paragraph 3.2 of JIS K-2514-1980. The results were as shown in Table 5.
Example 5 A hydrogenated benzyl-monoethylbiphenyl, a mixture of com-pounds of the formulas C?1~5 C2~5 ~ CH2 ~ ~ and O _CH2 ~ was obtained by following the procedure of Example 4, except 5 parts of mono-ethylbiphenyl and 0.03 part of aluminum chloride were used. The general attributes of this reaction product were as shown in Table 4. This product, compounded as described above, was tested for traction coefficient and subjected to the oxidation test specified in Paragraph 3.2 of JIS K-2514-1980. The results ~ 3, ~ HATTA-29 were as shown in Table 5.
Example 6 In a reactor, 1 liter of cyclohexylbenzene and 200 ml of concentrated sulfuric. acid were introduced and the resultant mixture was kept at 15C. Then, 800 ml of a 1:1 mixture of cyclohexylbenzene and styrene was added dropwise to the result~
ant mixture over a period of two hours, while the temperature of the mixture was kept in the range of from 15 to 20C. At the end of the dropwise addition of the mixture, 200 ml of concen-trated sulfuric acid was added to continue the reaction further for 30 minutes. Then, the reaction mixture was washed repeat-edly with water to remove residual sulfuric acid and then dis-tilled to isolate 1-(cyclohexylphenyl)-1-phenylethane (a mixture of structural isomers). Then, 1 liter of 1-(cyclohexylphenyl)-1-phenylethane was introduced in the autoclave and, in the presence of a nickel catalyst, subjected to hydrogenation under the conditions of 100 kg/cm2G of initial hydrogen pressure and 140 to 170C temperature for two hours, to afford hy-drogenated 1-(biphenylyl)-1-phenylethane (a mixture of struc-tural isomers). The general attributes of this hydrogenation product were as shown in Table 4.
A composition suitable for traction drives prepared by in-corporating into this hydrogenation product the same additives as given above, was tested for traction coefficient and sub-jected to the oxidation test specified in Paragraph 3.2 of JIS K-2514-1980. The results were as shown in Table 5.
Example 7 Hydrogenated 1-(ethylbiphenylyl)-1-phenylethane, a mix-ture of compounds of the formulas C \-CH ~ and C CH ~ was obtained ~3~ Z
~IA'I'I'A-29 by following the procedure of Example 6, except 1 liter of monoethylbiphenyl was used in the place of cyclohexylbenzene and 800 ml of a 1:1 mixture of monoethylbiphenyl and styrene was used in the place' of the mixture of cyclohexylbenzene and styrene. The general attributes of this product were shown in Table 4. This product, compounded as given above, was tested for traction coefficient and then subjected to the oxidation test specified in Paragraph 3.2 of JIS K-2514-1980. The results were as shown in Table 5 ~3'~'Z;Z

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t' ~ 3~Z~ HATTA-29 Example 8 Dodecylbenzene obtained by the reaction of propylene tetramer with benzene was introduced into an autoclave and, in the presence of a nickel catalyst, subjected to hydrogena-tion under the conditions of 50 kg/cm2G of initial hydrogen pressure and 150C of temperature for 4 hours, to afford alkylcyclohexane. An oil for traction drives was prepared by mixing 50 parts by volume of this alkylcyclohexane with 50 parts by volume of the hydrogenated dibenzyltoluene obtained in Example 1 and incorporating into this mixture 0.5 weight percent, based on the amount of the mixture, each of 2,6-di-tertiary-butyl-para-cresol and zinc dialkyl-dithiophosphate. This fluid was tested for traction coefficient and subjected to the oxida-tion test as specified in Paragraph 3.2 of JIS K 2514-1980. The results of the tests are shown together with the general attri-butes in Table 6.
Example 9 By following the procedure of Example 8, an oil for trac-tion drives was prepared from 50 parts by volume of alkylcyclo-hexane obtained in Example 8 and 50 parts by volume of hydro-genated benzylbiphenyl obtained in Example 4. Then, the fluid was subjected to the same tests as described in Example 8. The results were as shown in Table 6.

~ ~ ~ 3~ HATTA-29 _able 6 General Attributes Property Example 8 Example 9 Specific gravity (15/4C) 0.88 0.87 Appearance Colorless, Colorless, clear clear Viscosity (cst)(40C)20.2 17.5 Viscosity (cst)(100C) 3.4 . 3.1 Pour point (C) -37.5 -35 Flash point (C) 150 150 Hydrogenation ratio (%) 98 98 Traction Coefficient and Result of Oxydation Test Item of Test Example 8 Example 9 Traction coefficient 0.086 0.088 Oxidation Test:
Viscosity ratio 1.08 1.07 Increase of total acid number (mg KOH/g) 0.07 0.05 Heptane insolubles after oxidation text (weight %) 0.15 0.13 As shown by the Examples, the addition of dodecylcyclo-hexane gave compositions having substantially lower viscosities and substantially lower pour points without substantial loss in traction coefficient or stability to oxidation.
It is to be understood that the invention is not to be limited to the exact details of operation or exact compounds, compositions, methods, or procedures shown and described, as obvious modifications and equivalents will be apparent to one skilled in the art.

Claims (21)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A composition, suitable for use in mechanical power trans-mission units, consisting essentially of a minor amount of an antioxidant in admixture with a hydrocarbon oil which has from 19 through 30 carbon atoms and three six-membered carbocyclic rings and consists of a mixture of compounds having the following formula:

(I) wherein R1 is a divalent straight or branched chain radical CyH2y where y is an integer of 1 through 3; R2 is a straight chain radical CzH2z where z is an integer of 1 through 3; R3, R4, and R5 are the same or different alkyl groups having from 1 through 4 carbon atoms; ? , m, and n each is an integer from zero through 3; and x is zero or 1; and wherein rings A and B
are hydrogenated benzene rings and ring C is a hydrogenated benzene ring when X is 1 and a hydrogenated benzene ring or a cyclohexane ring when X is zero said hydrogenated benzene rings being saturated with hydrogen to the extent of at least 80% but less than 100% of the theoretical and said hydrocarbon oil being otherwise unsaturated.

2. A composition according to Claim 1, in which said benzene rings are saturated to at least 95%.

3. A composition according to Claim 1, in which X in the formula is 1.

4. A composition according to Claim 3, in which said hydro-carbon comprises hydrogenated 1-(benzylphenyl)-1-phenylethane -28- (Claims page 1) having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

5. A composition according to Claim 3, in which said hydro-carbon comprises hydrogenated dibenzylbenzene having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

6. A composition according to Claim 5, in which X in the formula is zero.

7. A composition according to Claim 6, in which said hydro-carbon comprises hydrogenated benzylbiphenyl having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

8. A composition according to Claim 6, in which said hydro-carbon comprises hydrogenated 1-biphenyl-1-phenylethane having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

9. A composition according to Claim 1, which contains addi-tionally up to 100 parts of an alkylcyclohexane in which the alkyl group contains from 9 through 20 carbon atoms for each 100 parts of said hydrocarbons.

10. A composition according to Claim 9, which contains addi-tionally from 10 to 60 parts of an alkylcyclohexane in which the alkyl group contains from 9 through 20 carbon atoms for each 100 parts of said hydrocarbons.

-29- (Claims page 2)

11. A process for operating traction drives which have an area of point or line contact between rolling solid bodies which comprises oiling the area of contact with hydrocarbon oil which has from 19 through 30 carbon atoms and three six-membered carbo-cyclic rings and consists of a mixture of compounds having the following formula:

(I) wherein R1 is a divalent straight or branched chain radical CyH2y where y is an integer of l through 3; R2 is a straight chain radical CzH2z where z is an integer of 1 through 3; R3, R4, and R5 are the same or different alkyl groups having from 1 through 4 carbon atoms; ? , m, and n each is an integer from zero through 3; and x is zero or 1; and wherein rings A and B
are hydrogenated benzene rings and ring C is a hydrogenated benzene ring when X is 1 and a hydrogenated benzene ring or a cyclohexane ring when X is zero said hydrogenated benzene rings being saturated with hydrogen to the extent of at least 80% but less than 100% of the theoretical and said hydrocarbon oil being otherwise unsaturated.

12. A process of Claim 11, in which the rings are saturated to at least 95%.

13. A process of Claim 11, in which the hydrocarbon oil is stabilized by an antioxidant.

-30- (Claims page 3)

14. A process according to Claim 11, in which X in the formula is 1.

15. A process of Claim 11, in which said hydrocarbon comprises hydrogenated (benzylphenyl)-phenylethane having from zero to to two, inclusive, methyl substituents and from zero to two, in-clusive, ethyl substituents.

16. A process of Claim 11, in which said hydrocarbon comprises hydrogenated dibenzylbenzene having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

17. A process of Claim 11, in which X in the formula is zero.

18. A process of Claim 11, in which said hydrocarbon comprises hydrogenated benzylbiphenyl having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

19. A process of Claim 11, in which said hydrocarbon comprises hydrogenated biphenyl-phenylethane having from zero to two, inclusive, methyl substituents and from zero to two, inclusive, ethyl substituents.

20. A process of Claim 11, which contains additionally up to 100 parts of an alkylcyclohexane in which the alkyl group con-contains from 9 through 20 carbon atoms for every 100 parts of said hydrocarbons.

21. A process of Claim 11, which contains additionally from 10 to 60 of an alkylcyclohexane in which the alkyl group con-tains from 9 through 20 carbon atoms for every 100 parts of said hydrocarbons -31- (Claims page 4)