Note: Descriptions are shown in the official language in which they were submitted.
HATTA-29
'~.
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.
HATTA-29
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.
HATTA- 2 9
,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.
HATTA-29
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-
--7--
~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-
H A T T A - 2 9
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
--10--
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
HATTA- 2 9
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
-12-
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).
-13-
HATTA-29
~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.
-15-
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.
-16-
HATTA-29
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
-17-
HATTA-29
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
HATTA-29
'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.
-18-
IIA5TA-29
~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
--1 9--
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.
--20--
1~3~
C I IJ ~13 3 ~ X ~t ~ ~-- o ~. ~ ~ U~
n I ~(D o PJ rt O ~ ~t g nO n
O I rt :~ O p) U~ - ~ h
t~ (D O ra O Pl -
't ~ ~ O n H ~ < ~ n o
rt 1 1- G O 1~ h O ~ o
O ~ ~
o I ~ ~ . ~ o O ô - _
,t b ~ .,
X rD
~, ~ ,t
tn I ~
~ ~_ o o o ~ ~ ~ ~_ ~ ~S
1- O'~ ~ O Ul a' ~t O ~Q
O U~ O ~_rt rD
O X ~h ~_ Q~ ~
o o 1- o ~ u n~ ~
~n o o ~D IJ (D ~
rD ~ ~S
~ ~ I_
O O 1-- 0 X w ~D N) O 1--
G ~ o ~1 o~ (D o 1_ 1_
_ o o ~ ~ 3~ ul w ~D rt ~ rt rt
~ ~ O:J n tD rD
W ~h X 3 ~ w
~ O (D ~1
rt ~D ~
rt rt
~ I' ::J' ~ ~ ~
n 3 ~ ~ 3 O - o
O o 1- o O W O ~3 0 I tD ~:C
:~ O ~ ~q rt ~DI ~ r It (D r~
~ ~h 3 rt r~ o ~ a~ w o ~ 3 1~ 0
<: O rD ~ ~3 ~ (D 1~ ~ 3
x n~ ~ w rt
3 fDpl tD rt (D
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~ rt
I (D
~ 1~
n ~ c~ o
(D
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I_
H~TTA- 2 9
37'~Z
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
-22-
~ 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
CH3 C2H5 CH3 C2H5
C \-CH ~ and C CH ~ was obtained
-23-
~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
-24-
~3'~'Z;Z
O ~, ~ H C~ 0 ~3
X (D n ~ !~ x It p, o
n u, 1- p.
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p) P) fD O P~ ( t H ~~ Pl 1-
1' o rD ~ o 1
O ~ O ~ 3 p~ n
C ~ c~ ~ Y ~ n
n o n ,.,. r~ q o
t ~3 0 ~h o ~ ~ It ~
rD OPJ ~D tD ~ ~ o n ~ (D
U~ I~ ^ ( t rt U~ ~h ~3 C> tl~ U~ C
rt ~ 3 o ~- ~ ~h rD ~ t rt 1'- rt
4 rt O .. ~. ~ t ~<:
P) O r~ c~
(D5~ J.
O (D O O o ,.~
o O ~_
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~ ~h ~q ~ n ~ ~
(D I t~ 3 o
o o ~~ o ~ (D
-- O O O ~ n
~ I_ ~n O
Vl rD I_ r
o ~ lC
. ;~
1-3 1 ~-- ~ .~
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t~ ~ W o ~ ~
X O ~ W ~- (D
P' rt~D ~ ' ~ ~ ~
O 0 1~ 0 ~ ~ Jl ~ ~3
. ~ O O (D (t
O ~ ~O- ~D (I) ~ ~_ ~ p.
n ~ ,_ ~D
n
x n o g 5: G~
o o I-- o 3 ~............ O N k~
. ~ ~ ~ ~ ~
_ o O ~~ ~ ~ 1'- I--~ ~D
CO C~ ~ ~D ~ 0~ 0 ~ 0~ (D O ~ ~ ~4 ~
, Ul ~D m ~9 g ~ ~ ~_
Q- ~ ~ O p)
t~ . n 1--
P~ ~ tD ~pJ ~S
o o 1- o 3 ~ ~:
l_ O o ~ l_
Ul 0~ 00 ~ (D ~ r~
n ~_ n
_l o o ~ I ~n
~^
O (D ~ ~C
s2 XO w I c~
~ '<: c~ O ~ O (D O 1--~ O
rt (~) Q~ n tD rD ~4
tt 1~ rt P) 3 O ~ W ~D rt ~ (D
p) ~ ~ ~ rt PJ '~ W ~<
~1. X P~
rt ~ ~ O n ~ ~ rt
i'- ~ I It ~ ~_ (I) ~
o o 1-- o O ~n o ~D _ ~,
~ O t ~ ~
1~ ~ ~ o 1~. ~< (D (D It I_
CO O O ~D Q~ u~
~ ) rt
1'- ~h ::~ rt
<: O rD (D n
(D ~ Q- O
U~ ~-- ~ rt
~- o ~a
~ )t
(D IJ (D 1--~t
I~ (D :~ ~ O
~ O U~ ~ ~-
- Ot)_~ o 1~ U~ o
.
U~ D rt (D
~ n w 3~ ~t
3 ~- 1
~ p) ~D
U~ w ro o ~ X ~ SD
~ o (D _
:~, IJ
O
t'
--25--
~ 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.
-26-
~ ~ ~ 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.
-27-
