U.S. patent application number 11/549034 was filed with the patent office on 2007-08-23 for lubricating oil composition.
Invention is credited to Hiroshi Kaneko, Hirohiko Otsu, Tetsuo Wakizono.
Application Number | 20070197411 11/549034 |
Document ID | / |
Family ID | 38441712 |
Filed Date | 2007-08-23 |
United States Patent
Application |
20070197411 |
Kind Code |
A1 |
Kaneko; Hiroshi ; et
al. |
August 23, 2007 |
Lubricating oil composition
Abstract
A lubricating oil composition is provided containing a base oil
having a kinematic viscosity at 40.degree. C. in the range of from
2 to 20 mm.sup.2/s and a viscosity index of 50 or more and a
polymethacrylate, wherein the lubricating oil composition has a
kinematic viscosity at 40.degree. C. in the range of from 22 to 95
mm.sup.2/s; a kinematic viscosity at 100.degree. C. in the range of
from 10 to 30 mm.sup.2/s; a pour point of -10.degree. C. or less; a
CCS viscosity at -20 .degree. C. of 2500 mPas or less; and a flash
point of 140.degree. C. or more.
Inventors: |
Kaneko; Hiroshi; (Tokyo,
JP) ; Otsu; Hirohiko; (Tokyo, JP) ; Wakizono;
Tetsuo; (Tokyo, JP) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
38441712 |
Appl. No.: |
11/549034 |
Filed: |
October 12, 2006 |
Current U.S.
Class: |
508/469 |
Current CPC
Class: |
C10M 2205/0285 20130101;
C10M 2223/041 20130101; C10M 2203/1006 20130101; C10N 2010/12
20130101; C10M 2205/028 20130101; C10M 2207/026 20130101; C10N
2030/02 20130101; C10M 2223/045 20130101; C10M 171/02 20130101;
C10M 2229/041 20130101; C10M 145/14 20130101; C10M 2207/2825
20130101; C10M 2209/084 20130101; C10M 2207/282 20130101; C10N
2020/02 20130101; C10N 2020/04 20130101; C10M 2203/1006 20130101;
C10M 2203/1006 20130101 |
Class at
Publication: |
508/469 |
International
Class: |
C10M 145/14 20060101
C10M145/14 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 2005 |
EP |
2005-298746 |
Claims
1. A lubricating oil composition comprising a base oil having a
kinematic viscosity at 40.degree. C. in the range of from 2 to 20
mm.sup.2/s and a viscosity index of 50 or more and a
polymethacrylate, wherein the lubricating oil composition has a
kinematic viscosity at 40.degree. C. in the range of from 22 to 95
mm.sup.2/s; a kinematic viscosity at 100.degree. C. in the range of
from 10 to 30 mm.sup.2/s; a pour point of -10.degree. C. or less; a
CCS viscosity at -20.degree. C. of 2500 mPas or less; and a flash
point of 140.degree. C. or more.
2. The lubricating oil composition of claim 1 wherein the weight
average molecular weight of the polymethacrylate is in the range of
from 150,000 to 700,000.
3. The lubricating oil composition of claim 2 wherein the weight
average molecular weight of the polymethacrylate is in the range of
from 200,000 to 500,000.
4. The lubricating oil composition of claim 1 wherein the viscosity
index of the base oil is 70 or more.
5. The lubricating oil composition of claim 1 wherein the
lubricating oil composition further comprises at least one type of
additive selected from an anti-wear agent, an antioxidant, an
anti-rust agent, a corrosion inhibitor and an antifoaming
agent.
6. The lubricating oil composition of claim 1 wherein said
lubricating oil composition is a hydraulic oil composition for a
door closer or a hydraulic oil composition for a floor hinge or
both.
7. The lubricating oil composition of claim 2 wherein the viscosity
index of the base oil is 70 or more.
8. The lubricating oil composition of claim 7 wherein the
lubricating oil composition further comprises at least one type of
additive selected from an anti-wear agent, an antioxidant, an
anti-rust agent, a corrosion inhibitor and an antifoaming
agent.
9. The lubricating oil composition of claim 5 wherein said
lubricating oil composition is a hydraulic oil composition for a
door closer or a hydraulic oil composition for a floor hinge or
both.
10. A method of lubricating a door closer or a floor hinge
comprising using a lubricating oil composition of claim 1 to
lubricate said door closer or floor hinge.
11. A method of lubricating a door closer or a floor hinge
comprising using a lubricating oil composition of claim 2 to
lubricate said door closer or floor hinge.
12. A method of lubricating a door closer or a floor hinge
comprising using a lubricating oil composition of claim 4 to
lubricate said door closer or floor hinge.
13. A method of lubricating a door closer or a floor hinge
comprising using a lubricating oil composition of claim 7 to
lubricate said door closer or floor hinge.
14. A method of lubricating a door closer or a floor hinge
comprising using a lubricating oil composition of claim 8 to
lubricate said door closer or floor hinge.
Description
FIELD OF THE INVENTION
[0001] The present invention relates lubricating oil compositions,
in particular to hydraulic oil compositions. More specifically, the
present invention relates to a hydraulic oil composition for use in
a door closer or a floor hinge employed for opening/closing various
types of doors.
BACKGROUND OF THE INVENTION
[0002] Door closers using hydraulic oil compositions are widely
employed for door opening/closing. Such door closers slowly close a
door which has been manually opened, and when the door is caused by
a wind or the like to move abruptly, the door closer is required to
have the function of slowing down the motion of the door lest it
should close on a hand.
SUMMARY OF THE INVENTION
[0003] A lubricating oil composition is provided comprising a base
oil having a kinematic viscosity at 40.degree. C. in the range of
from 2 to 20 mm.sup.2/s and a viscosity index of 50 or more and a
polymethacrylate,
wherein the lubricating oil composition has a kinematic viscosity
at 40.degree. C. in the range of from 22 to 95 mm.sup.2/s; a
kinematic viscosity at 100.degree. C. in the range of from 10 to 30
mm.sup.2/s;
[0004] a pour point of -10.degree. C. or less; [0005] a CCS
viscosity at -20.degree. C. of 2500 mPas or less; and [0006] a
flash point of 140.degree. C. or more.
[0007] A method of lubricating a door closer or a floor hinge using
such lubricating oil composition is also provided.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The door closer fundamentally comprises a cylinder, a piston
and an orifice, and prevents the door from being abruptly closed
due to the resistance generated by the passage of a hydraulic oil
composition through the orifice.
[0009] Since the door closer uses a hydraulic oil composition,
sometimes opening and closing of the door becomes difficult due to
temperature fluctuations. For example, during high temperature in
summer, the viscosity of a hydraulic oil composition is decreased
and thus the hydraulic oil composition passes through the orifice
in a shorter period of time, leading to abrupt closing of the door.
In contrast, during low temperature in the cold season, the
viscosity of a hydraulic oil composition is increased and it takes
a longer period of time to pass through the orifice, thereby
causing the problem that an unduly long period of time is required
for closing the door, and also that an unduly large force is
required for opening the door.
[0010] Ordinarily, for lubricating oil compositions in general,
when viscosity is to be increased for the purpose of viscosity
adjustment, a polymer having a large molecular weight is added to a
mineral oil or a synthetic oil. However, if such a polymer having
large molecular weight is added to the oil, although the viscosity
of the oil at high temperature is increased, the viscosity under
low temperature is also increased. Therefore, when the oil is used
in machinery, problems sometimes occur, particularly when the
machinery is operated at low temperature.
[0011] Further, mineral oil contains a wax component which is
crystallized at low temperature, and such wax crystals grow with
time and thereby lower flowability of the oil. As a result, the oil
comes to have an increased viscosity or sometimes may even become
solidified. In order to prevent such a wax component from being
crystallized, a pour-point depressant which is adsorbed on the wax
crystals and suppresses the growth of the crystals is generally
used; however, there are cases where because of the pour-point
depressant the viscosity of the oil does not increase at high
temperatures.
[0012] Still further, after a door closer is fixed to a building,
it is used for a long period of time, and during such period, there
is a tendency for the hydraulic oil composition to deteriorate. The
thus-deteriorated oil hardens the oil seal so that the hydraulic
oil composition leaks and becomes reduced in quantity. As a result,
there are cases in which the door closer does not function
satisfactorily. In particular, in order to perform the opening
and/or closing of a door smoothly, a typical hydraulic oil
composition is a mineral oil or synthetic oil having a low
viscosity, which also causes a problem of compatibility with the
oil seal.
[0013] In addition, as per Japanese Laid-open Patent Application
No. H. 5-747488 it has been pointed out that when a mineral oil
having low viscosity is used, a large amount of viscosity index
improving agent needs to be added to the oil in order to increase
the viscosity, and a problem arises regarding flowability of the
oil at low temperatures.
[0014] It is highly desirable to obtain hydraulic oil compositions
which show little fluctuation of viscosity over low temperatures
and high temperatures and which can operate in the same condition
at any time.
[0015] The present invention provides lubricating oil composition,
in particular a hydraulic oil composition, comprising a base oil
having a kinematic viscosity at 40.degree. C. in the range of from
2 to 20 mm.sup.2/s and a viscosity index of 50 or more and a
polymethacrylate, wherein the lubricating oil composition has a
kinematic viscosity at 40.degree. C. in the range of from 22 to 95
mm.sup.2/s; a kinematic viscosity at 100.degree. C. in the range of
from 10 to 30 mm.sup.2/s; a pour point of -10.degree. C. or less; a
CCS (cold cranking shear) viscosity at -20.degree. C. of 2500 mPas
or less; and a flash point of 140.degree. C. or more.
[0016] The polymethacrylate used in the lubricating oil composition
of the present invention preferably has a weight average molecular
weight in the range of from 150,000 to 700,000.
[0017] In the present invention, the lubricating oil composition,
in particular the hydraulic oil composition, is uninfluenced by hot
or cold and shows practically the same degree of viscosity whether
at low temperature or high temperature and stays in the same
condition at all times, thereby making it possible to achieve
smooth operation in, for example, a door closer. Also, since the
lubricating oil composition, in particular the hydraulic oil
composition is compatible with oil seals, problems of oil leakage
seldom occur even over long periods. In addition, apart from in
door closers or floor hinges as referred to above, the lubricating
oil composition of the present invention may be widely employed as
hydraulic oil composition of various types.
[0018] In a preferred embodiment of the present invention, the
lubricating oil composition, in particular the hydraulic oil
composition, has a viscosity index of at least 260.
[0019] The base oil in the lubricating oil composition of the
present invention may be conveniently chosen from mineral oils,
synthetic oils and mixtures thereof.
[0020] Mineral oils that may be conveniently used include base oils
manufactured by conducting one or more treatments such as solvent
deasphalting, solvent extraction, hydrocracking, solvent dewaxing,
or hydrorefining on the lubricating oil fraction obtained from the
reduced pressure distillation of reduced crude obtained by
atmospheric distillation of crude oil.
[0021] Various types of synthetic oil may be conveniently used as
the synthetic oil. Examples of synthetic oils include so-called GTL
(gas-to-liquid) base oils obtained by solvent dewaxing or contact
dewaxing after synthesis using the Fischer-Tropsch process. Other
examples of synthetic oils that may be conveniently used include
poly-.alpha.-olefins (for example ethylene-propylene copolymers,
polybutylenes, 1-octene oligomers, 1-decene oligomers, and hydrides
thereof), alkyl benzenes, alkyl naphthalenes, monoesters (for
example, butyl stearate or octyl stearate), diesters (for example,
ditridecyl glutarate, dioctyl adipate, diisodecyl adipate,
ditridecyl adipate, dioctyl sebacate, or dioctyl azelate),
polyesters (for example, trimellitate esters), polyol esters (for
example, trimethylol propane caprylate, trimethylol propane
pelargonate, pentaerythritol-2-ethyl hexanoate, or pentaerythritol
pelargonate), polyphenyl ethers and dialkyl diphenyl ethers.
[0022] The kinematic viscosity at 40.degree. C. of the base oil is
generally in the range of from 2 to 20 mm.sup.2/s, preferably in
the range of from 5 to 15 mm.sup.2/s.
[0023] If the kinematic viscosity of the base oil exceeds 20
mm.sup.2/s, when the above polymethacrylate is added, the
high-temperature kinematic viscosity of the lubricating oil
composition may become too high, or, if polymethacrylate is added
in an amount in accordance with the required high-temperature
viscosity, the low temperature flowability may become poor due to
the base oil failing to reach the necessary viscosity index
mentioned below, due to paucity of addition of
polymethacrylate.
[0024] On the contrary, if the kinematic viscosity of the base oil
is less than 2 mm.sup.2/s, then the viscosity-increasing effect may
become poor at more than a certain added content of the
polymethacrylate, even if polymethacrylate is added in accordance
with the prescribed high-temperature viscosity, and on the other
hand the low-temperature viscosity may become large, with the
result that the required low-temperature flowability cannot be
obtained, or problems arise regarding safety in that the flash
point becomes less than 140.degree. C.
[0025] The viscosity index of the above base oil used in the
lubricating oil composition of the present invention is generally
50 or more and preferably 70 or more. If the viscosity index of the
base oil is low, then more polymethacrylate must be added in order
to obtain the prescribed viscosity index, thereby lowering the
solubility of the polymethacrylate at high temperature, with the
possible consequence that the target viscosity index may not be
achieved.
[0026] There are no particular restrictions regarding the upper
limit of the viscosity index of the base oil, and for example base
oils that may be used include normal paraffins, slack wax, GTL wax
or a substance of viscosity index about 135 to 180, such as an
isoparaffin-based mineral oil obtained by isomerisation.
[0027] The pour point of the above base oil is generally
-10.degree. C. or less, preferably -20.degree. C. or less, more
preferably -30.degree. C. or less and most preferably -37.5.degree.
C. or less. If the pour point of the base oil is -10.degree. C. or
less, solidification of the hydraulic oil at low temperature can be
prevented.
[0028] On the contrary, if the pour point is higher than
-10.degree. C., then even if polymethacrylate or a pour point
depressant is added, it is difficult to obtain the necessary low
temperature flowability for the lubricating oil composition.
[0029] The polymethacrylate that is added to the above base oil may
be, for example, a non-dispersion type polymethacrylate or a
dispersion type polymethacrylate. Non-dispersion type
polymethacrylates include copolymers of one or more monomers
selected from compounds expressed by the following general formula
(1), ##STR1## general formula (2), ##STR2## and general formula
(3), ##STR3## and hydrides thereof.
[0030] Dispersion type polymethacrylates include, for example,
copolymers of two or more monomers selected from compounds
expressed by the following general formula (4), ##STR4## and
general formula (5), ##STR5## or compounds obtained by introducing
an oxygen-containing group into hydrides of these or copolymers of
one or more 15 monomers selected from compounds expressed by the
above general formula (1) to general formula (3) and one or more
monomers selected from compounds expressed by the above general
formula (4) or general formula (5) and hydrides thereof.
[0031] In the above general formula (1), R.sup.1 represents a
hydrogen atom or methyl group and R.sup.2 represents an alkyl group
having a carbon number in the range of from 1 to 18. Examples of
alkyl groups having a carbon number in the range of from 1 to 18
represented by R.sup.2 include: a methyl group, ethyl group, propyl
group, butyl group, pentyl group, hexyl group, heptyl group, octyl
group, nonyl group, decyl group, undecyl group, dodecyl group,
tridecyl group, tetradecyl group, pentadecyl group, hexadecyl
group, heptadecyl group and octadecyl group (these alkyl groups may
be of straight chain or branched form).
[0032] In the above general formula (2), R.sup.3 represents a
hydrogen atom or methyl group and R.sup.4 represents a hydrocarbon
group having a carbon number in the range of from 1 to 12. Examples
of hydrocarbon groups having a carbon number in the range of from 1
to 12 represented by R.sup.4 include: alkyl groups such as a methyl
group, ethyl group, propyl group, butyl group, pentyl group, hexyl
group, heptyl group, octyl group, nonyl group, decyl group, undecyl
group, or a dodecyl group, (these alkyl groups may be of straight
chain or branched form); a cycloalkyl group having a carbon number
in the range of from 5 to 7 such as a cyclopentyl group, cyclohexyl
group, or a cycloheptyl group; an alkyl cycloalkyl group having a
carbon number in the range of from 6 to 11 such as a methyl
cyclopentyl group, dimethyl cyclopentyl group, methylethyl
cyclopentyl group, diethyl cyclopentyl group, methyl cyclohexyl
group, dimethyl cyclohexyl group, methylethyl cyclohexyl group,
diethyl cyclohexyl group, methyl cycloheptyl group, dimethyl
cycloheptyl group, methylethyl cycloheptyl group, or diethyl
cycloheptyl group (the position of substitution of the alkyl groups
in the cycloalkyl groups is not limited and may be chosen as
required); an alkenyl group such as a butenyl group, pentenyl
group, hexenyl group, heptenyl group, octenyl group, nonenyl group,
decenyl group, undecenyl group, dodecenyl group (these alkenyl
groups may be of straight chain or branched form and the position
of the double bond is not limited and may be chosen as required);
an aryl group such as a phenyl group or naphthyl group; an
alkylaryl group having a carbon number in the range of from 7 to 12
such as a tolyl group, xylyl group, ethyl phenyl group, propyl
phenyl group, butyl phenyl group, pentyl phenyl group, or hexyl
phenyl group (these alkyl groups may be of straight chain or
branched form, and the position of substitution into the aryl group
is not limited and may be chosen as required); or an arylalkyl
group having a carbon number in the range of from 7 to 12 such as a
benzyl group, phenyl ethyl group, phenyl propyl group, phenyl butyl
group, phenyl pentyl group, or phenyl hexyl group (these alkyl
groups may be of straight chain or branched form).
[0033] In the above general formula (3), X.sup.1 and X.sup.2 are
independently selected from a hydrogen atom, an alkoxy group
--OR.sup.10 having a carbon number in the range of from 1 to 18
(wherein R.sup.10 is an alkyl group having a carbon number in the
range of from 1 to 18) or a monoalkyl amino group --NHR.sup.11
having a carbon number in the range of from 1 to 18 (wherein
R.sup.11 is an alkyl group having a carbon number in the range of
from 1 to 18).
[0034] In the above general formula (4), R.sup.5 indicates a
hydrogen atom or methyl group, R.sup.6 indicates an alkylene group
having a carbon number in the range of from 1 to 18, Y.sup.1
indicates an amine residue or heterocyclic residue containing from
1 to 2 nitrogen atoms and from 0 to 2 oxygen atoms, and a is 0 or
1.
[0035] The alkylene group having a carbon number in the range of
from 1 to 18 indicated by R.sup.8 may be, for example, an ethylene
group, a propylene group, butylene group, pentylene group, hexylene
group, heptylene group, octylene group, nonylene group, decylene
group, undecylene group, dodecylene group, tridecylene group,
tetradecylene group, pentadecylene group, hexadecylene group,
heptadecylene group or octadecylene group (these alkylene groups
may be of straight chain or branched form).
[0036] Also, the group indicated by Y.sup.1 may be, for example, a
dimethylamino group, diethylamino group, dipropylamino group,
dibutylamino group, anilino group, toluidino group, xylidino group,
acetylamino group, benzoylamino group, morpholino group, pyrrolyl
group, pyrrolino group, pyridyl group, methyl pyridyl group,
pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl
group, pyrrolidono group, imidazolino group or pyrazino group.
[0037] In the above general formula (5), R.sup.7 indicates a
hydrogen atom or methyl group, and Y.sup.2 indicates an amine
residue or heterocyclic residue containing from 1 to 2 nitrogen
atoms and from 0 to 2 oxygen atoms.
[0038] The group indicated by Y.sup.2 may be, for example, a
dimethylamino group, diethylamino group, dipropylamino group,
dibutylamino group, anilino group, toluidino group, xylidino group,
acetylamino group, benzoylamino group, morpholino group, pyrrolyl
group, pyrrolino group, pyridyl group, methyl pyridyl group,
pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl
group, pyrrolidono group, imidazolino group or pyrazino group.
[0039] Preferred examples of one or more monomers selected from the
compounds indicated by general formula (1) to general formula (3)
include: alkyl acrylates having a carbon number in the range of
from 1 to 18, alkylamide methacrylates having a carbon number in
the range of from 1 to 18, olefins having a carbon number in the
range of from 2 to 20, styrene, methyl styrene, maleic anhydride
esters, maleic anhydride amides and mixtures thereof.
[0040] Preferred examples of one or more monomers selected from the
compounds indicated by general formula (4) and general formula (5)
include: dimethylamino methyl methacrylate, diethylamino methyl
methacrylate, dimethylamino ethyl methacrylate, 2-methyl-5-vinyl
pyridine, morpholino methyl methacrylate, morpholino ethyl
methacrylate, N-vinyl pyrrolidone and mixtures thereof.
[0041] The copolymerisation mol ratio of a copolymer of one or more
monomers selected from the compounds indicated by the above general
formula (1) to general formula (3) to one or more monomers selected
from the compounds indicated by general formula (4) and general
formula (5) is typically about 80:20 to 95:5, respectively.
[0042] The method of manufacture of said copolymers is not limited,
but, a copolymer can conveniently be obtained by radical solvent
polymerisation of the monomers in the presence of a polymerisation
initiator such as benzoyl peroxide.
[0043] The weight average molecular weight of the above
polymethacrylate is preferably in the range of from 150,000 to
700,000, more preferably in the range of from 200,000 to 500,000,
and is preferably selected taking into account the rate of increase
of viscosity per unit mass and the rate of improvement of the
viscosity index.
[0044] In the lubricating oil composition of the present invention,
polymethacrylate is employed in an amount such as to produce a
kinematic viscosity at 40.degree. C. in the range of from 22 to 95
mm.sup.2/s and may be blended with a suitable amount of one or more
compounds selected from the various types of polymethacrylate
referred to above. If the kinematic viscosity at 40.degree. C. is
less than 22 mm.sup.2/s, the high-temperature viscosity is
insufficient; on the other hand, if the CCS (cold-cranking shear)
viscosity at -20.degree. C. exceeds 2500 mPas, closure at a low
temperature becomes slow, thereby presenting an obstacle to
use.
[0045] A suitable content of polymethacrylate is added to the base
oil in order to ensure that the kinematic viscosity of the above
lubricating oil composition at 40.degree. C. is within the above
range. The amount of polymethacrylate is preferably in the range of
from 0.1 to 30 weight %, with reference to the total weight of the
lubricating oil composition.
[0046] The lubricating oil composition of the present invention,
apart from the above base oil and polymethacrylate, may be
conveniently blended with additional additives, for example, with
anti-wear agents, antioxidants, rust inhibitors, corrosion
inhibitors and/or anti-foaming agents.
[0047] Anti-wear agents that may be conveniently used include
phosphorus-based compounds, organic molybdenum compounds, fatty
acid ester compounds and aliphatic amine based compounds.
[0048] Examples of phosphorus-based compounds that may be
conveniently used include zinc alkyl thiophosphate, phosphoric
acid, phosphorous acid, phosphoric acid monoesters, phosphoric acid
diesters, phosphoric acid triesters, phosphorous acid monoesters,
phosphorous acid diesters, phosphorous acid triesters, salts of
phosphoric (phosphorous) acid esters, and thiophosphoric acid or
thiophosphorous acid and esters thereof, as well as mixtures
thereof.
[0049] The above components listed as phosphorus-based compounds,
with the exception of phosphoric acid, thiophosphoric acid,
phosphorous acid and thiophosphorous acid, are normally compounds
containing a hydrocarbon group having a carbon number in the range
of from 2 to 30, preferably in the range of from 3 to 20.
[0050] As such hydrocarbon groups having a carbon number in the
range of from 2 to 30, there may be mentioned by way of example
alkyl groups, cycloalkyl groups, alkyl cycloalkyl groups, alkenyl
groups, aryl groups, alkylaryl groups and arylalkyl groups.
[0051] As said alkyl groups, there may be mentioned by way of
example alkyl groups such as ethyl groups, propyl groups, butyl
groups, pentyl groups, hexyl groups, heptyl groups, octyl groups,
nonyl groups, decyl groups, undecyl groups, dodecyl groups,
tridecyl groups, tetradecyl groups, pentadecyl groups, hexadecyl
groups, pentadecyl groups and octadecyl groups (these alkyl groups
may be of straight chain form or branched form).
[0052] As said cycloalkyl groups, there may be mentioned by way of
example cycloalkyl groups having a carbon number in the range of
from 5 to 7 such as a cyclopentyl group, cyclohexyl group or
cycloheptyl group.
[0053] As said alkyl cycloalkyl groups, there may be mentioned by
way of example alkyl cycloalkyl groups having a carbon number in
the range of from 6 to 11 such as a methyl cyclopentyl group,
dimethyl cyclopentyl group, methyl ethyl cyclopentyl group, diethyl
cyclopentyl group, methyl cyclohexyl group, dimethyl cyclohexyl
group, methyl ethyl cyclohexyl group, dimethyl cyclohexyl group,
methyl cycloheptyl group, dimethyl cycloheptyl group, methyl ethyl
cycloheptyl group and diethyl cycloheptyl group (the position of
substitution of the alkyl group into the cycloalkyl group is not
limited and may be chosen as required).
[0054] As said alkenyl groups, there may be mentioned by way of
example alkenyl groups such as butenyl groups, pentenyl groups,
hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups,
decenyl groups, undecenyl groups, dodecenyl groups, tetradecenyl
groups, pentadecenyl groups, hexadecenyl groups, heptadecenyl
groups, and octadecenyl groups (these alkenyl groups may be of
straight chain or branched form and the position of the double bond
is not limited and may be chosen as required).
[0055] As said aryl groups, there may be mentioned by way of
example aryl groups such as phenyl groups and naphthyl groups.
[0056] As said alkylaryl groups, there may be mentioned by way of
example alkylaryl groups having a carbon number in the range of
from 7 to 18, such as a tolyl group, xylyl group, ethyl phenyl
group, propyl phenyl group, butyl phenyl group, pentyl phenyl
group, hexyl phenyl group, heptyl phenyl group, octyl phenyl group,
nonyl phenyl group, decyl phenyl group, undecyl phenyl group and
dodecyl phenyl group (these alkyl groups may be of straight chain
or branched form, and the position of substitution into the aryl
group is not limited and may be chosen as required).
[0057] As said arylalkyl groups, there may be mentioned by way of
example arylalkyl groups having a carbon number in the range of
from 7 to 12, such as a benzyl group, phenyl ethyl group, phenyl
propyl group, phenyl butyl group, phenyl pentyl group and phenyl
hexyl group (these alkyl groups may be of straight chain or
branched form).
[0058] Preferred phosphorus-based compounds include phosphoric
acid; phosphorous acid; zinc alkyl dithiophosphates such as zinc
dipropyl dithiophosphate, zinc dibutyl dithiophosphate, zinc
dipentyl dithiophosphate, zinc dihexyl dithiophosphate, zinc
diheptyl dithiophosphate, or zinc dioctyl dithiophosphate (these
alkyl groups may be of straight chain form or branched form);
monoalkyl esters of phosphoric acid such as monopropyl phosphate,
monobutyl phosphate, monopentyl phosphate, monohexyl phosphate,
monoheptyl phosphate, or monooctyl phosphate (these alkyl groups
may be of straight chain form or branched form); mono(alkyl)aryl
esters of phosphoric acid such as monophenyl phosphate and
monocresyl phosphate; dialkyl esters of phosphoric acid such as
dipropyl phosphate, dibutyl phosphate, dipentyl phosphate, dihexyl
phosphate, diheptyl phosphate and dioctyl phosphate (these alkyl
groups may be of straight chain form or branched form);
di(alkyl)aryl esters of phosphoric acid such as diphenyl phosphate
and dicresyl phosphate; trialkyl esters of phosphoric acid such as
tripropyl phosphate, tributyl phosphate, tripentyl phosphate,
trihexyl phosphate, triheptyl phosphate and trioctyl phosphate
(these alkyl groups may be of straight chain form or branched
form); tri(alkyl)aryl esters of phosphoric acid such as triphenyl
phosphate and tricresyl phosphate; monoalkyl esters of phosphorous
acid such as monopropyl phosphite, monobutyl phosphite, monopentyl
phosphite, monohexyl phosphite, monoheptyl phosphite and monooctyl
phosphite (these alkyl groups may be of straight chain form or
branched form); mono(alkyl)aryl esters of phosphorous acid such as
monophenyl phosphite and monocresyl phosphite; dialkyl esters of
phosphorous acid such as dipropyl phosphite, dibutyl phosphite,
dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, and
di-octyl phosphite (these alkyl groups may be of straight chain
form or branched form); di(alkyl)aryl esters of phosphorous acid
such as diphenyl phosphite and dicresyl phosphite; trialkyl esters
of phosphorous acid such as tripropyl phosphite, tributyl
phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl
phosphate and trioctyl phosphite (these alkyl groups may be of
straight chain form or branched form); tri(alkyl)aryl esters of
phosphorous acid such as triphenyl phosphite, and tricresyl
phosphite; and mixtures of these.
[0059] Also, as the salts of phosphoric (phosphorous) acid esters,
listed above, salts may be conveniently used which are obtained by
reacting a nitrogen-containing compound such as ammonia or an amine
compound containing in the molecule a hydrocarbon group having a
carbon number in the range of from 1 to 8 or a hydroxyl
group-containing hydrocarbon group with for example phosphoric acid
monoester, phosphoric acid diester, phosphorous acid monoester, or
phosphorous acid diester and neutralising part or all of the
remaining acidic hydrogen.
[0060] Examples of said nitrogen-containing compounds include
ammonia; alkylamines such as monomethylamine, monoethylamine,
monopropylamine, monobutylamine, monopentylamine, monohexylamine,
monoheptylamine, mono-octylamine, dimethylamine, methyl ethylamine,
diethylamine, methyl propylamine, ethyl propylamine, dipropylamine,
methyl butylamine, ethyl butylamine, propyl butylamine,
dibutylamine, dipentylamine, dihexylamine, diheptylamine and
dioctylamine (these alkyl groups may be of straight chain form or
branched form); alkanolamines such as monomethanolamine,
monoethanolamine, monopropanolamine, monobutanolamine,
monopentanolamine, monohexanolamine, monoheptanolamine,
mono-octanolamine, monononanolamine, dimethanolamine, methanol
ethanolamine, diethanolamine, methanol propanolamine, ethanol
propanolamine, dipropanolamine, methanol butanolamine, ethanol
butanolamine, propanol butanolamine, dibutanolamine,
dipentanolamine, dihexylanolamine, diheptanolamine and
dioctanolamine (these alkanol groups may be of straight chain form
or branched form); and mixtures thereof.
[0061] Any one or more of the above phosphorus compounds may be
blended together in use.
[0062] Organic molybdenum-based compounds may be conveniently used
as the above anti-wear agent. Typical compounds include molybdenum
dithiocarbamates, molybdenum dithiophosphates and amine
molybdenates. Molybdenum dithiocarbamates are particularly
preferred.
[0063] Examples of such molybdenum dithiocarbamates include
compounds of general formula (6) ##STR6##
[0064] examples of such molybdenum dithiophosphates include
compounds of general formula (7) ##STR7##
[0065] and examples of such amine molybdenates include compounds of
general formula (8) ##STR8##
[0066] In the above general formula (6), general formula (7) and
general formula (8), R.sup.12 to R.sup.21 are hydrocarbon groups
having a carbon number in the range of from 6 to 18 and may be
respectively the same or different. X and Y indicate a sulphur atom
or oxygen atom, a.ltoreq.3, b.ltoreq.3 and c.ltoreq.3.
[0067] One of said organic molybdenum-based compounds may be
employed in the lubricating oil composition of the present
invention. Alternatively, two or more of said organic
molybdenum-based compounds may be used therein in combination.
[0068] The content of said organic molybdenum-based compounds,
expressed in terms of the molybdenum content, is preferably at
least 200 weight ppm, more preferably in the range of from 400 to
2000 weight ppm, and even more preferably in the range of from 600
to 1000 weight ppm. If the above content of organic
molybdenum-based compound is less than 200 weight ppm, then the
anti-wear effect may be low; if the content exceeds 2000 weight
ppm, the effect of such addition of organic molybdenum-based
compounds may become saturated.
[0069] As the fatty acid ester compounds and/or aliphatic
amine-based compounds of the above anti-wear agent, fatty acid
esters, aliphatic amine compounds or any desired mixture of these
having straight chain or branched hydrocarbon groups having a
carbon number in the range of 6 to 30, preferably having a carbon
number in the range of 8 to 24 and even more preferably having a
carbon number in the range of 10 to 20 may be employed.
[0070] Examples that may be given of such straight chain or
branched hydrocarbon groups having a carbon number in the range of
6 to 30 include: alkyl groups such as a hexyl group, heptyl group,
octyl group, nonyl group, decyl group, undecyl group, dodecyl
group, tridecyl group, tetradecyl group, pentadecyl group,
hexadecyl group, heptadecyl group, octadecyl group, nonadecyl
group, eicosyl group, heneicosyl group, docosyl group, tricosyl
group, tetracosyl group, pentacosyl group, hexacosyl group,
heptacosyl group, octacosyl group, nonacosyl group and triacontyl
group, or alkenyl groups such as a hexenyl group, heptenyl group,
octenyl group, nonenyl group, decenyl group, undecenyl group,
dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl
group, hexadecenyl group, heptadecenyl group, octadecenyl group,
nonadecenyl group, eicosenyl group, heneicosenyl group, docosenyl
group, tricosenyl group, tetracosenyl group, pentacosenyl group,
hexacosenyl group, heptacosenyl group, octacosenyl group,
nonacosenyl group and triacontenyl group. It should be noted that
the above alkyl groups and alkenyl groups include all conceivable
straight chain constructions and branched chain constructions, and
the position of the double bond in the alkenyl groups may be chosen
as required.
[0071] As the above fatty acid esters, there may be mentioned by
way of example esters comprising a fatty acid having a hydrocarbon
group as above and an aliphatic monohydric alcohol or an aliphatic
polyhydric alcohol. Specific examples of fatty acid esters that may
be conveniently used include glycerine mono-oleate, glycerine
dioleate, sorbitan mono-oleate and sorbitan dioleate.
[0072] Examples of aliphatic amine compounds that may be
conveniently used in the lubricating oil composition of the present
invention include aliphatic monoamines or their alkylene oxide
addition products, aliphatic polyamines or imidazoline compounds,
and derivatives thereof. Specific examples of said aliphatic amine
compounds include laurylamine, lauryl diethylamine, lauryl
diethanolamine, dodecyl dipropanolamine, palmitylamine,
stearylamine, stearyl tetramethylene pentamine, oleylamine, oleyl
propylene diamine, oleyl diethanolamine, and N-hydroxyethyl oleyl
imidazoline, or amine alkylene oxide addition products such as the
N, N-dipolyoxyalkylene-N-alkyl (or alkenyl) (having a carbon number
in the range of from 6 to 28) addition products of these aliphatic
amine compounds, or so-called acid-modified compounds obtained by
reacting monocarboxylic acids (fatty acids etc) or oxalic acid,
phthalic acid, trimellitic acid, pyromellitic acid or the like
polycarboxylic acids having a carbon number in the range of from 2
to 30 with these aliphatic amine compounds and neutralisation or
amidation of some or all of the remaining amino groups and/or imino
groups. A suitable example is
N,N-dipolyoxyethylene-N-oleylamine.
[0073] Examples of the aforementioned anti-rust agents include
petroleum sulphonates, alkyl benzene sulphonates, dinonyl
naphthalene sulphonate, alkenyl succinic acid esters, and
polyhydric alcohol esters.
[0074] Examples of the aforementioned corrosion inhibitors include
benzotriazole-based, tolyl triazole-based, thiadiazole-based and
imidazole-based compounds.
[0075] The aforementioned oxidation inhibitors include phenyl-based
oxidation inhibitors and amine-based oxidation inhibitors.
[0076] Preferred examples of phenol-based oxidation inhibitors that
may be conveniently used in the lubricating oil composition of the
present invention include 4,4'-methylene bis(2,6-di-tert-butyl
phenol); 4,4'-bis(2,6-di-tert-butyl phenol),
4,4'-bis(2-methyl-6-tert-butyl phenol); 2,2'-methylene
bis(4-ethyl-6-tert-butyl phenol); 2,2'-methylene
bis(4-methyl-6-tert-butyl phenol); 4,4'-butylidene
bis(3-methyl-6-tert-butyl phenol); 4,4'-isopropylidene bis(2,6-di
-tert-butyl phenol); 2,2'-methylene bis(4-methyl-6-nonyl phenol);
2,2'-isobutylidene bis(4,6-dimethyl phenol); 2,2'-methylene
bis(4-methyl-6-cyclohexyl phenol); 2,6-di-tert-butyl-4-methyl
phenol; 2,6-di-tert-butyl-4-ethyl phenol; 2,4-dimethyl-6-tert-butyl
phenol; 2,6-di-tert-a-dimethylamino-p-cresol;
2,6-di-tert-butyl-4(N, N'-dimethylaminomethyl phenol);
4,4'-thiobis(2-methyl-6-tert-butyl phenol);
4,4'-thiobis(3-methyl-6-tert-butyl phenol); 2,2'-thiobis(4-methyl
-6-tert-butyl phenol); bis(3-methyl-4-hydroxy-5-tert-butyl benzyl)
sulphide; bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulphide;
2,2'-thio-diethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)
propionate]; tridecyl-3-(3, 5-di-tert-butyl-4-hydroxyphenyl)
propionate; pentaerythrityl-tetrakis
[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]; octyl-3-(3,5-di
-tert-butyl-4-hydroxyphenyl) propionate; octadecyl-3-(3,
5-di-tert-butyl-4-hydroxyphenyl) propionate; or octyl-3-(3-methyl
-5-tert-butyl-4-hydroxyphenyl) propionate. One or more of the
aforementioned oxidation inhibitors may be used in the lubricating
oil composition of the present invention.
[0077] Examples of amine-based oxidation inhibitors that may be
conveniently used in the lubricating oil composition of the present
invention include substituted and non-substituted
phenyl-.alpha.-naphthylamines, alkyl phenol-.alpha.-naphthylamines,
and dialkyl diphenylamines. One or more of the aforementioned
oxidation inhibitors may be used in the lubricating oil composition
of the present invention.
[0078] Furthermore, the aforementioned phenol-based oxidation
inhibitors and amine-based oxidation inhibitors may be used in
combination in the lubricating oil composition of the present
invention.
[0079] Examples of antifoaming agents that may be conveniently used
in the lubricating oil composition of the present invention include
a silicone, fluorosilicone, or fluoroalkyl ether.
[0080] The present invention further provides the use of the
lubricating oil composition of the present invention for
lubricating a door closer or a floor hinge. There is also provided
a method of lubricating a door closer or a floor hinge comprising
using the lubricating oil composition of the present invention to
lubricate said door closer or floor hinge.
[0081] The lubricating oil composition of the present invention can
be conveniently prepared by blending together the base oil having a
kinematic viscosity at 40.degree. C. in the range of from 2 to 20
mm.sup.2/s and a viscosity index of 50 or more with a
polymethacrylate and, optionally, one or more additives as
hereinbefore described.
[0082] The present invention is described below with reference to
the following Examples, which are not intended to limit the scope
of the invention in any way.
EXAMPLES
Example 1
[0083] 21.8 parts by weight of mineral oil (B) having a kinematic
viscosity of 99.21 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 11.14 mm.sup.2/s at 100.degree. C., a flash point of
268.degree. C. and a viscosity index of 97 was mixed with 62.2
parts by weight of mineral oil (C) having a kinematic viscosity of
8.74 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 2.23
mm.sup.2/s at 100.degree. C., a flash point of 160.degree. C. and a
viscosity index of 41, to obtain a mixed base oil having a
kinematic viscosity of 15.1 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 3.22 mm.sup.2/s at 100.degree. C. and a
viscosity index of 74. This mixed base oil was blended with 16
parts by weight of a polymethacrylate (a) having a weight average
molecular weight of 270,000.
[0084] The resulting lubricating oil composition had a kinematic
viscosity 68.8 mm.sup.2/s at 40.degree. C., a kinetic viscosity of
17.92 mm.sup.2/s at 100.degree. C., a viscosity index of 281, a
pour point of less than -50.degree. C., a CCS viscosity at
-20.degree. C. of 1120 mPas, and a flash point of 156.degree.
C.
[0085] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region.
[0086] As an oil seal compatibility test, an immersion test of 1000
hours at oil temperature of 100.degree. C. was conducted on said
lubricating oil composition in accordance with the procedure of JIS
K 6258 "Method of immersion testing of vulcanised rubber", and the
external appearance and physical properties of the oil seal
determined after conducting the test, in order to evaluate
compatibility. Excellent results were obtained with said
lubricating oil composition and compatibility with the oil seal was
confirmed.
Example 2
[0087] 20 parts by weight of a mineral oil (A) having a kinematic
viscosity of 24.98 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 4.64 mm.sup.2/s at 100.degree. C., a flash point of
222.degree. C. and a viscosity index of 101 was mixed with 63.7
parts by weight of a mineral oil (E) having a kinematic viscosity
of 4.22 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 1.51
mm/s at 100.degree. C., a flash point of 142.degree. C., to obtain
a mixed base oil having a kinematic viscosity of 5.93 mm.sup.2/s at
40.degree. C., a kinematic viscosity of 1.89 mm.sup.2/s at
100.degree. C. and a viscosity index of 108. This mixed base oil
was blended with 16.3 parts by weight of a polymethacrylate (b)
having a weight average molecular weight of 400,000.
[0088] The resulting lubricating oil composition had a kinematic
viscosity of 29.86 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 10.49 mm.sup.2/s at 100.degree. C., a viscosity index
of 367, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 1900 mPas, and a flash point of 146.degree.
C.
[0089] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 3
[0090] 21.3 parts by weight of a mineral oil (B) having a kinematic
viscosity of 99.21 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 11.14 mm.sup.2/s at 100.degree. C. and a flash point
of 268.degree. C. was mixed with 62.2 parts by weight of a mineral
oil (C) of kinematic viscosity of 8.74 mm2/s at 40.degree. C.,
kinematic viscosity of 2.23 mm.sup.2/s at 100.degree. C., a flash
point 160.degree. C. and a viscosity index of 41, to obtain a mixed
base oil having a kinematic viscosity of 15.1 mm.sup.2/s at
40.degree. C., a kinematic viscosity of 3.22 mm.sup.2/s at
100.degree. C. and a viscosity index of 74.
[0091] This mixed base oil was blended with 16 parts by weight of a
polymethacrylate (a) of weight average molecular weight 270,000,
0.2 parts by weight of the phosphorus compound TCP (tricresyl
phosphate) as anti-wear agent, 0.3 parts by weight of hindered
phenol based oxidation inhibitor, 0.05 parts by weight of a
oxyalkyl carboxylic acid ester (content 70%) and 0.001 parts by
weight of antifoaming agent dimethyl siloxane.
[0092] The resulting lubricating oil composition had a kinematic
viscosity of 67.4 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 18.0 mm.sup.2/s at 100.degree. C., a viscosity index
of 288, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 1080 mPas, and a flash point of 156.degree.
C.
[0093] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 4
[0094] 20 parts by weight of a mineral oil (A) having a kinematic
viscosity of 24.98 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 4.64 mm.sup.2/s at 100.degree. C. and a flash point of
222.degree. C. were mixed with 63 parts by weight of a mineral oil
(E) of kinematic viscosity of 4.22 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 1.51 mm.sup.2/s at 100.degree. C., and a
flash point of 142.degree. C., to obtain a mixed base oil having a
kinematic viscosity of 5.93 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 1.89 mm.sup.2/s at 100.degree. C. and a
viscosity index of 108. This mixed base oil was blended with 16.3
parts by weight of polymethacrylate (b) having a weight average
molecular weight of 400,000, 0.5 parts by weight of the phosphorus
compound TCP (tricresyl phosphate) as anti-wear agent, 0.2 parts by
weight of the organic molybdenum compound molybdenum dialkyl
thiophosphate and 0.001 parts by weight of antifoaming agent
dimethyl siloxane.
[0095] The resulting lubricating oil composition had a kinematic
viscosity of 29.39 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 10.53 mm.sup.2/s at 100.degree. C., a viscosity index
of 375, a pour point less than -50.degree. C., a CCS viscosity at
-20.degree. C. of 1890 mPas, and a flash point of 146.degree.
C.
[0096] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 5
[0097] 6.5 parts by weight of a mineral oil (B) having a kinematic
viscosity of 99.21 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 11.14 mm.sup.2/s at 100.degree. C., a flash point of
268.degree. C. and a viscosity index of 97 was mixed with 24.4
parts by weight of a mineral oil (C) having a kinematic viscosity
of 8.74 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 2.23
mm.sup.2/s at 100.degree. C., a flash point of 160.degree. C. and a
viscosity index of 41, 36.7 parts by weight of "XHVI" oil ("XHVI"
is a trade mark for synthetic hydrocarbon base oils sold by the
Shell Group) having a kinematic viscosity of 23.6 mm.sup.2/s at
40.degree. C., a kinematic viscosity of 5.51 mm.sup.2/s at
100.degree. C., a flash point of 244.degree. C. and a viscosity
index 148, and 7.35 parts by weight of DOA (dioctyl adipate) to
obtain a mixed base oil having a kinematic viscosity of 15.03
mm.sup.2/s at 40.degree. C., a kinematic viscosity of 3.49
mm.sup.2/s at 100.degree. C. and a viscosity index of 109.
[0098] This mixed base oil was blended with 24.5 parts by weight of
a polymethacrylate (a) having a weight average molecular weight of
270,000, 0.2 parts by weight of the phosphorus compound TCP
(tricresyl phosphate) as anti-wear agent, 0.3 parts by weight of a
hindered phenol based oxidation inhibitor, 0.05 parts by weight of
an oxyalkyl carboxylic acid ester (content 70%) and 0.001 parts by
weight of antifoaming agent dimethyl siloxane.
[0099] The resulting lubricating oil composition had a kinematic
viscosity of 28.6 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 10.15 mm.sup.2/s at 100.degree. C., a viscosity index
of 314, a pour point -45.degree. C., a CCS viscosity at -20.degree.
C. of 1450 mPas, and a flash point of 182.degree. C.
[0100] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 6
[0101] 48.73 parts by weight of mineral oil (C) having a kinematic
viscosity of 8.74 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 2.23 mm.sup.2/s at 100.degree. C., a flash point of
160.degree. C. and a viscosity index of 41 was mixed with 29.74
parts by weight of a mineral oil (D) having a kinematic viscosity
of 19.24 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 4.19
mm/s at 100.degree. C., a flash point of 234.degree. C. and a
viscosity index of 123, to obtain a mixed base oil having a
kinematic viscosity of 11.93 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 2.85 mm.sup.2/s at 100.degree. C. and a
viscosity index of 81. To this mixed base oil were added 20.98
parts by weight of a polymethacrylate (a) having a weight average
molecular weight of 270,000, 0.2 parts by weight of phosphorus
compound TCP (tricresyl phosphate) as anti-wear agent, 0.3 parts by
weight of a hindered phenol based oxidation inhibitor, 0.05 parts
by weight of an oxyalkyl carboxylic acid ester (content 70%) and
0.001 parts by weight of antifoaming agent dimethyl siloxane.
[0102] The resulting lubricating oil composition had a kinematic
viscosity of 71.76 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 21.48 mm.sup.2/s at 100.degree. C., a viscosity index
of 323, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 660 mPas, and flash point of 160.degree.
C.
[0103] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 7
[0104] 56.89 parts by weight of a mineral oil (C) having a
kinematic viscosity of 8.74 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 2.23 mm.sup.2/s at 100.degree. C., a flash
point of 160.degree. C. and a viscosity index of 41, 7.86 parts by
weight of a mineral oil (E) of kinematic viscosity of 4.22
mm.sup.2/s at 40.degree. C., a kinematic viscosity of 1.51
mm.sup.2/s at 100.degree. C., a flash point of 142.degree. C., and
10 parts by weight of poly-.alpha.-olefin (PAO) of kinematic
viscosity of 34.87 mm2/s at 40.degree. C., a kinematic viscosity of
6.38 mm.sup.2/s at 100.degree. C. and a viscosity index of 136 were
mixed to obtain a mixed base oil of a kinematic viscosity of 9.56
mm.sup.2/s at 40.degree. C., a kinematic viscosity 2.44 mm.sup.2/s
at 100.degree. C. and a viscosity index 71.
[0105] This mixed base oil was blended with 24.66 parts by weight
of a polymethacrylate (a) having a weight average molecular weight
of 270,000, 0.2 parts by weight of the phosphorus compound TCP
(tricresyl phosphate) as anti-wear agent, 0.3 parts by weight of a
hindered phenol based oxidation inhibitor, 0.05 parts by weight of
a oxyalkyl carboxylic acid ester (content 70%) and 0.001 parts by
weight of antifoaming agent dimethyl siloxane.
[0106] The resulting lubricating oil composition had a kinematic
viscosity of 80.38 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 24.88 mm.sup.2/s at 100.degree. C., a viscosity index
of 335, pour point of less than -50.degree. C., a CCS viscosity at
-20.degree. C. of 730 mPas, and a flash point of 150.degree. C.
[0107] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 8
[0108] 44.26 parts by weight of mineral oil (E) having a kinematic
viscosity of 4.22 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 1.51 mm.sup.2/s at 100.degree. C., a flash point of
142.degree. C., and 25.36 parts by weight of a poly-.alpha.-olefin
(PAO) having a kinematic viscosity of 34.87 mm.sup.2/s at
40.degree. C., a kinematic viscosity of 6.38 mm.sup.2/s at 100
degrees, a flash point of 258.degree. C. and a viscosity index of
136 were mixed to obtain a mixed base oil having a kinematic
viscosity of 8.31 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 2.42 mm.sup.2/s at 100.degree. C. and a viscosity
index of 118.
[0109] This mixed base oil was blended with 29.83 parts by weight
of a polymethacrylate (a) having a weight average molecular weight
of 270,000, 0.2 parts by weight of the phosphorus compound TCP
(tricresyl phosphate) as anti-wear agent, 0.3 parts by weight of a
hindered phenol based oxidation inhibitor, 0.05 parts by weight of
oxyalkyl carboxylic acid ester (content 70%) and 0.001 parts by
weight of antifoaming agent dimethyl siloxane.
[0110] The resulting lubricating oil composition had a kinematic
viscosity of 88.97 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 8.49 mm.sup.2/s at 100.degree. C., a viscosity index
of 347, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 730 mPas, and a flash point of 150.degree.
C.
[0111] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 9
[0112] 10.2 parts by weight of a mineral oil (A) having a kinematic
viscosity of 24.98 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 4.64 mm.sup.2/s at 100.degree. C., a flash point of
222.degree. C. and a viscosity index of 101 was mixed with 50.75
parts by weight of a mineral oil (C) having a kinematic viscosity
of 8.74 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 2.23
mm.sup.2/s at 100.degree. C., a flash point of 160.degree. C. and a
viscosity index 41, and with 20.3 parts by weight of a mineral oil
(D) having a kinematic viscosity of 19.24 mm.sup.2/s at 40.degree.
C., a kinematic viscosity of 4.19 mm.sup.2/s at 100.degree. C., a
flash point of 234.degree. C. and a viscosity index of 123, to
obtain a mixed base oil having a kinematic viscosity of 12.16
mm.sup.2/s at 40.degree. C., a kinematic viscosity of 2.87
mm.sup.2/s at 100.degree. C. and a viscosity index 78.
[0113] This mixed base oil was blended with 18.2 parts by weight of
a polymethacrylate (a) having a weight average molecular weight of
270,000, 0.2 parts by weight of the phosphorus compound TCP
(tricresyl phosphate) as anti-wear agent, 0.3 parts by weight of a
hindered phenol based oxidation inhibitor, 0.05 parts by weight of
an oxyalkyl carboxylic acid ester (content 70%) and 0.001 parts by
weight of antifoaming agent dimethyl siloxane.
[0114] The resulting lubricating oil composition had a kinematic
viscosity of 61.59 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 18.22 mm.sup.2/s at 100.degree. C., a viscosity index
of 315, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 660 mPas, and a flash point of 160.degree.
C.
[0115] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Example 10
[0116] 9.8 parts by weight of a mineral oil (A) having a kinematic
viscosity of 24.98 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 4.64 mm.sup.2/s at 100.degree. C., a flash point of
222.degree. C. and a viscosity index of 101 was mixed with 63.9
parts by weight of a mineral oil (E) having a kinematic viscosity
of 4.22 mm.sup.2/s at 40.degree. C., a kinematic viscosity of 1.51
mm.sup.2/s at 100.degree. C., and a flash point of 142.degree. C.,
to obtain a mixed base oil having a kinematic viscosity of 5.11
mm.sup.2/s at 40.degree. C., a kinematic viscosity of 1.71
mm.sup.2/s at 100.degree. C. and a viscosity index of 109.
[0117] This mixed base oil was blended with 24.6 parts by weight of
a polymethacrylate (a) having a weight average molecular weight of
270,000, 0.5 parts by weight of the phosphorus compound TCP
(tricresyl phosphate) as anti-wear agent, 1.0 parts by weight of
hindered phenol based oxidation inhibitor, 0.2 parts by weight of
the organic molybdenum compound molybdenum dialkyl thiophosphate
and 0.001 parts by weight of antifoaming agent dimethyl
siloxane.
[0118] The resulting lubricating oil composition had a kinematic
viscosity of 52.16 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 19.58 mm.sup.2/s at 100.degree. C., a viscosity index
of 390, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 2350 mPas, and a flash point of 142.degree.
C.
[0119] This lubricating oil composition had fully satisfactory
properties for use as a hydraulic oil composition for a door closer
from the low temperature region to the high temperature region and
also showed excellent results in the above oil seal compatibility
test.
Comparative Example 1
[0120] 79.45 parts by weight of a mineral oil (F) having a
kinematic viscosity of 8.66 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 2.19 mm.sup.2/s at 100.degree. C., a flash
point of 136.degree. C. and a viscosity index of 30 was mixed with
20 parts by weight of a polymethacrylate (a) having a weight
average molecular weight of 270,000, 0.2 parts by weight of the
phosphorus compound TCP (tricresyl phosphate) as anti-wear agent,
0.3 parts by weight of a hindered phenol based oxidation inhibitor,
0.05 parts by weight of an oxyalkyl carboxylic acid ester (content
70%) and 0.001 parts by weight of antifoaming agent dimethyl
siloxane.
[0121] The resulting lubricating oil composition had a kinematic
viscosity of 53.49 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 7.19 mm.sup.2/s at 100.degree. C., a viscosity index
of 339, a pour point of less than -50.degree. C., CCS viscosity at
-20.degree. C. of 925 mPas, and a flash point of 128.degree. C.
[0122] This lubricating oil composition was found to be lacking in
compatibility in the above oil seal compatibility test and was of
low flashpoint and was consequently unsuitable for use as a
hydraulic oil composition for a door closer.
Comparative Example 2
[0123] 79.45 parts by weight of a mineral oil (F) having a
kinematic viscosity of 8.66 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 2.19 mm.sup.2/s at 100.degree. C., a flash
point of 136.degree. C. and a viscosity index of 30 was mixed with
20 parts by weight of a polymethacrylate (a) having a weight
average molecular weight of 400,000, 0.2 parts by weight of the
phosphorus compound TCP (tricresyl phosphate) as anti-wear agent,
0.3 parts by weight of a hindered phenol based oxidation inhibitor,
0.05 parts by weight of an oxyalkyl carboxylic acid ester (content
70%) and 0.001 parts by weight of antifoaming agent dimethyl
siloxane.
[0124] The resulting lubricating oil composition had a kinematic
viscosity of 55.32 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 15.9 mm.sup.2/s at 100.degree. C., a viscosity index
of 304, a pour point less than -50.degree. C., a CCS viscosity at
-20.degree. C. of 810 mpas, and a flash point of 128.degree. C.
[0125] This lubricating oil composition was found to be lacking in
compatibility in the above oil seal compatibility test and was of
low flashpoint and was consequently unsuitable for use as a
hydraulic oil composition for a door closer.
Comparative Example 3
[0126] 89.45 parts by weight of mineral oil (A) having a kinematic
viscosity of 24.98 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 4.64 mm.sup.2/s at 100.degree. C., a flash point of
222.degree. C. and a viscosity index of 101 was mixed with 10 parts
by weight of a polymethacrylate (a) having a weight average
molecular weight of 270,000, 0.2 parts by weight of the phosphorus
compound TCP (tricresyl phosphate) as anti-wear agent, 0.3 parts by
weight of a hindered phenol based oxidation inhibitor, 0.05 parts
by weight of an oxyalkyl carboxylic acid ester (content 70%) and
0.001 parts by weight of antifoaming agent dimethyl siloxane.
[0127] The resulting lubricating oil composition had a kinematic
viscosity of 58 mm.sup.2/s at 40.degree. C., a kinematic viscosity
of 13.81 mm.sup.2/s at 100.degree. C., a viscosity index of 249, a
pour point of -45.degree. C., a CCS viscosity at -20.degree. C. of
3050 mpas, and a flash point 128.degree. C.
[0128] Whilst this lubricating oil composition was found to be
compatible in the above oil seal compatibility test, it had a high
CCS viscosity at -20.degree. C. and was consequently unsuitable for
use as a hydraulic oil composition for a door closer.
Comparative Example 4
[0129] 79.45 parts by weight of a poly-.alpha.-olefin (PAO) having
a kinematic viscosity of 34.87 mm.sup.2/s at 40.degree. C., a
kinematic viscosity of 6.38 mm.sup.2/s at 100 degrees, a flash
point of 258.degree. C. and a viscosity index of 136 was mixed with
20 parts by weight of a polymethacrylate (a) having a weight
average molecular weight of 270,000, 0.2 parts by weight of the
phosphorus compound TCP (tricresyl phosphate) as anti-wear agent,
0.3 parts by weight of a hindered phenol based oxidation inhibitor,
0.05 parts by weight of an oxyalkyl carboxylic acid ester (content
70%) and 0.001 parts by weight of antifoaming agent dimethyl
siloxane.
[0130] The resulting lubricating oil composition kinematic
viscosity of 93.31 mm.sup.2/s at 40.degree. C., a kinematic
viscosity of 22.48 mm.sup.2/s at 100.degree. C., a viscosity index
of 270, a pour point of less than -50.degree. C., a CCS viscosity
at -20.degree. C. of 3450 mPas, and a flash point of 250.degree.
C.
[0131] This lubricating oil composition had a high CCS viscosity at
-20.degree. C., and produced shrinkage of the oil seal, and was
therefore unsuitable for use as hydraulic oil composition for a
door closer.
* * * * *