Title of Invention: LUBRICATING OE COMPOSITION FOR
M A C m G TOOL
5
Technical Field
[0001] The present invention relates to a lubricant composition for a
machining tool, and specifically relates to a lubricant composition that
is suitably used in lubricating of a slideway surface of a machining tool
10 and used as an oil for use in a hydraulic apparatus.
Background Art
[0002] Lubricants for slideway surfaces such as work tables of
machining tools are required to have lubricity in order to improve
15 working accuracy. Then, in order to meet such a requirement, a
lubricant to which additives such as an extreme pressure agent and an
oiliness agent are blended is used. In addition, such lubricants are also
required to have lubricity to a hydraulic pump as accessory equipment
of a machining tool in terms of a proper operation of a machining tool,
20 and a lubricant to which additives such as an extreme pressure agent and
an oiliness agent are blended is used.
[0003] Examples of such additives include phosphoric acid esters,
acidic phosphoric acid esters, phosphorous acid esters, carboxylic acids,
a sulfur compound and amines (see, for example, Patent Literature 1).
25 In addition, there has been attempted to neutralize an acidic phosphoric
acid ester by an alkyl amine to thereby result in the improvement in
stability (see, for example, Patent Literature 2).
[0004] In addition, oiliness agents include amines such as monoamines,
polyamines and alkanolamines (see, for example, Patent Literatures 2
and 3). Monoamines and polyamines are blended as a simple
5 substailce thereof (see, for example, Patent Literature 2). In addition,
with respect to alkanolamines, a method in which they are used as a,
compound for forming a salt such as an ainine salt with an acidic
phosphoric acid ester or an amide with a carboxylic acid is described
(see, for example, Patent Literature 3).
10
Citation List
Patent Literature
[0005] [Patent Literature 11 Japanese Patent Application Laid-Open No.
8-134488
15 patent Literature 21 Japanese Patent Application Laid-Open No.
2007-238764
patent Literature 31 Japanese Patent Application Laid-Open No.
2008-013688
20 Summary of Invention
Technical Problem
[0006] In recent years, however, a further improvement in lubricity has
been. required. Then, a conventional lubricant to which the above
additives are blended is difficult to meet such a requirement, and in
25 particular antiwear performance tends to be insufEcient.
[0007] The present invention has been made in view of such
circumstances, and an object thereof is to provide a lubricant
compositioa for a machining tool, having an excellent antiwear
perfomlance.
5 Solution to Problem
[0008] The present inventors have made intensive studies in order to
achieve the above object, and as a result, have found that the above
problem is solved by a lubricant composition containing a lubricant base
oil, and a specific phosphoric acid ester compound, a specific acidic
10 phosphoric acid ester and a sulfur compound in respective specific
amounts, leadiilg to the completion ofthe present invention.
[0009] That is, the lubricant composition for a machining tool of the
present invention contains:
lubricant base oil; and,
15 based on a total amount of the composition,
0.05 to 5% by mass of a phosphoric acid ester represented by the
following general formula (1):
(R'o)~P=o (1)
wherein R' represents any of an aryl group having 6 to 15 carbon atoms
20 and a saturated hydrocarbon group having 1 to 20 carbon atoms, and
each R' may be the same or different;
0.01. to 2% by mass of an acidic phosphoric acid ester represented by
the following general formula (2):
(~~o)np(=o)(o~),n) (2)
25 wherein R~ represents an alkyl group having 4 to 20 carbon atoms, n
represents 1 or 2, and R2 may be the same or different; and
0.5 to 5% by mass of a sulfiu- compound.
[0010] R' jn the above general formula (2) preferably represents an
alkyl group having 8 carbon atoms.
[0011] In addition, R' in the above general formula (1) preferably
5 represenfs a saturated hydrocarbon group having 1 to 20 carbon atoms.
[0012] The lubricant composition for a machining tool of the present
invention may be suitably used as a lubricant for simultaneously
lubricating a slideway surface and a hydraulic pump of a machining
tool.
10
Advantageous Effects of Invention
[0013] The lubricant composition of the present invention is excellent
in antiwear performance. Accordingly, the lubricant composition of
the present invention is very useful in tenns of stabilization of an
15 operation of a machining tool and high machining accuracy. Also in
lubricating of a hydraulic pump, the lubricant composition of the
present invention is very useful in terms of antiweax performance.
Description of Embodiments
20 [0014] Hereinafter, a suitable embodiment of the present invention will
be described in detail.
[0015] A lubricant composition for a machining tool according to an
embodiment of the present invention contains:
lubricant base oil; and
25 (A) a phosphoric acid ester rep~esented by the following general
formula (1) (hereinafter, also referred to as "component (A)".):
(R'o)~P===o (I)
wherein R' represents any of an alyl group having 6 to 15 carbon atoms
and a saturated hydrocarbon group having 1 to 20 carbon atoms, and
each R' may be the same or different;
5 (B) an acidic phosphoric acid ester represented by the followirig general
formula (2) (hereinafter, also refesred to as "component (B)".):
@20)np(=0)(0m(3.n) (2)
wherein R2 represents an alkyl group having 4 to 20 carbon atoms, n
represents 1 or 2, and each R' may be the same or different; and
10 (C) a s u l h conlpound (hereinafter, also referred to as "component
(C)".). The contents of the component (A) to the component (C) are,
based on the total amount of the composition, 0.05 to 5% by mass, 0.01
to 2% by mass, and 0.5 to 5% by mass, respectively.
[0016] The lubricant base oil in the present embodiment is not
15 particularly restricted, but examples thereof include a mineral oil, oil
and fat, and a synthetic oil.
[0017] The mineral oil is not particularly restricted in terms of the
production method thereof, and examples thereof include a paraffinic or
naphthenic mineral oil that is obtainable by applying, to a lubricant
20 fraction obtainable by distilling a crude oil at ordinary pressure or under
reduced pressure, one or a combination of two or more of refining
measures such as solvent deasphalting, solvent extraction,
hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining,
sulfuric acid washing and a clay treatment.
25 [0018] Examples of the oil and fat include beef tallow, lard, a soybean
oil, a rapeseed oil, a rice bran oil, a coconut oil, a palm oil, a palm
kernel oil, or 2 hydrogenated product thereof. In addition, the oil and
fat in which the content of an oleic acid is increased by means of a
recombinant DNA technology may also be suitably used.
[0019] Examples of the synthetic oil include poly-a-olehs (an
5 ethylene-propylene copolymer, polybutene, a 1-octe11c oligomer, a
1-decene oligomer, hydrides thereof, and the like), alkylbenzenes,
alkylnaphthalenes, monoesters (butyl stearate, octyl laurate and the like),
diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate,
ditridecyl adipate, di-2-ethylhexyl sebacate and the like), polyesters
10 (trimellitic acid esters and the like), polyol esters (trimethylolpropane
caprylate, trimethylolpropane pelargonate,
pentae~ythritol-2-ethylhexanoate,p entaesythritol pelagonate and the
like), polyoxyalkylene glycols, polyphenyl ethers, dialkyl diphenyl
ethers, phosphoric acid esters (tricresyl phosphate and the like), a
15 fluorine-containing compound (perfluoropolyethers, fluorinated
polyoleiins and the like) and a silicone oil.
[00201 In the present embodiment, as the lubricant base oil, one
selected from the above mineral oils, oils and fats and synthetic oils
may be used singly, or two or more selected therefrom may be used in
20 combination.
[0021] The viscosity of the lubricant base oil is not particularly
restricted, but the kinematic viscosity at 40°C thereof is preferably 10 to
700 rnm2/s and more preferably 15 to 500 m d s .
[0022] In addition, the content of the lubricant base oil is not
25 particularly limited, but is preferably 50 to 99.98% by mass based on
the total amount of the composition.
[0023] 'i'he phosphoric acid ester of the component (A) is a conlpound
represented by the above general formula (I), and is an orthophosphoric
acid ester having a group selected koin an aryl group having 6 to 15
carbon atoms (preferably an aryl group having 6 to 9 carbon atoms) and
5 a saturated hydrocarbon group having 1 to 20 carbon atoms (preferably
a saturated hydrocarbon soup having 4 to 12 carbon atoms), Inore
preferably a saturated hydrocarbon group having 8 to 12 carbon atoms.
[0024] Specific examples of the phosphoric acid ester of the component
(A) include tsiphenyl phosphate, hkresyl phosphate, trixylenyl
10 phosphate, aesyl diphenyl phosphate, xylenyl diphenyl phosphate,
tris(isopropylpheny1) phosphate, tris(t-butylphenyl) phosphate, tributyl
phosphate (including linear or branched ones), tripentyl phosphate
(including linear or branched ones), trihexyl phosphate (including linear
or branched ones), triheptyl phosphate (including linear or branched
15 ones), trioctyl phosphate (including linear or branched ones), trinonyl
phosphate (including linear or branched ones), tridecyl phosphate
(including linear or branched ones), triundecyl phosphate (including
linear or branched ones), tridodecyl phosphate (including linear or
branched ones), tritridecyl phosphate (including linear or branched
20 ones), tritetradecyl phosphate (icluding linear or branched ones),
tripentadecyl phosphate (including linear or branched ones),
trihexadecyl phosphate (icluding linear or branched ones),
triheptadecyl phosphate (including linear or branched ones), trioctadecyl
phosphate (including linear or branched ones) and trioleyl pl~osphate
25 (including linear or branched ones).
[0025] Among them, triphenyl phosphate, tricresyl phosphate, triheptyl
phosphate (including linear or branched ones), tsioctyl pllosphate
(including linear or branched ones), trinonyl phosphate (inchding linear
or branched ones) and tridecyl phosphate (including linear or branched
ones) are preferable;
5 tricresyl phosphate and trioctyl phosphate (including linear or branched
ones) are more preferable;
trioctyl phosphate (including linear or branched ones) is further
preferable; and
tri(2-ethylhexy1)phosphate is particularly preferable.
10 LO0261 The content of the phosphoric acid ester of the component (A) is
0.05% by mass or more, preferably 0.1% by mass or more and more
preferably 0.2% by mass or more, and 5% by mass or less and
preferably 3% by mass or less, based on the total amount of the
composition. If the content is less than 0.05% by mass, antiwear
15 performance is insufficient. In addition, if the content is more th+5%
by mass, the antiwear performance improvement effect corresponding
to the content is not achieved, and such a case is not preferable in terms
of economic efficiency.
[0027] The acidic phosphoric acid ester of the component (B) is a
20 compound represented by the above general f o ~ d (a2) , and is an
acidic phosphoric acid ester having an alkyl goup having 4 to 20
carbon atoms.
[0028] Specific examples of the acidic phosphoric acid ester of the
component (l3) include monoalkyl acidic phosphoric acid esters, dialkyl
25 acidic phosphoric acid esters, and mixtures thereof. The alkyl group of
these alkyl acidic phosphoric acid esters may be a linear or branched
alkyl group and may be saturated or unsaturated, but is preferably 1inea.r.
The number of carbon atoms in the allcyl group is 4 to 20, preferably 6
to 16 and more preferably 6 to 10, and a linear alkyl group having 8
carbon atoms (n-octyl group) is most preferable. In addition, the
5 numbers of carbon atoms in the two alkyl groups of the dialhyl acidic
phosphoric acid esters may be the same or different.
If the number of carbon atoms is 4 or less, such a case is not
preferable because solubility is poor. In addition, if the number of
carbon atoms is more than 20, the effect per unit mass is impaired and
10 such a case is not preferable:
[0029] Specific examples of the allcyl group having 4 to 20 carbon
atoms include a butyl group, a pentyl group, a hexyl group, a heptyl
group, an odyl. group, a nonyl group, a decyl group, an undecyl group, a
dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group,
15 a hexadecyl group, a heptadecyl group, an octadecyl group and a
nonadecyl group, and it is possible for each of them to use saturated or
unsaturated linear, or saturated or unsaturated branched one.
[0030] Specific examples of the acidic phosphoric acid ester include
mono-n-butyl acid phosphate, mono-n-pentyl acid phosphate,
20 mono-n-hexyl acid phosphate,
mono-n-heptyl acid acid phosphate, mono-n-octyl acid phosphate,
mono-n-nonyl acid phosphate, mono-n-decyl acid phosphate,
mono-n-dodecyl acid phosphate, mono-n-octadecyl acid phosphate,
mono-iso-butyl acid phosphate, mono-iso-pentyl acid phosphate,
25 mono-iso-hexyl acid phosphate, mono-iso-heptyl acid acid phosphate,
mono-iso-octyl acid phosphate, mono-iso-nonyl acid phosphate,
mono-iso-decyl acid phosphate, mono-iso-dodecyl acid phospl~ate,
mono-iso-hexadecyl acid phosphate, mono-iso-octadecyl acid
phosphate, di-n-butyl acid phosphate, di-n-pentyl acid phosphate,
di-n-hexyl acid phosphate, di-n-heptyl acid acid phosphate, di-11-octyl
5 acid phosphate, di-n-nonyl acid phosphate, di-n-decyl acid phosphate,
di-n-dodecyl acid phosphate, di-n-octadecyl acid phosphate, di-iso-butyl
acid phosphate, di-iso-pentyl acid phosphate, di-iso-hexyl acid
phosphate, di-iso-heptyl acid acid phosphate, di-iso-octyl acid
phosphate, di-iso-nonyl acid phosphate, di-iso-decyl acid phosphate,
10 di-iso-dodecyl acid phosphate, di-iso-hexadecyl acid phosphate and
di-iso-octadecyl acid phosphate.
[0031] Among them, mono-n-hexyl acid phosphate, mono-n-heptyl
acid acid phosphate, mono-n-octyl acid phosphate, mono-n-nonyl acid
phosphate, mono-n-decyl acid phosphate, di-n-hexyl acid phosphate,
15 di-n-heptyl acid acid phosphate, di-n-octyl acid phosphate, di-n-nonyl
acid phosphate, di-n-decyl acid phosphate, di-n-hexyl acid phosphate,
di-n-heptyl acid acid phosphate, di-n-octyl acid phosphate, di-n-nonyl
acid phosphate, di-n-decyl acid phosphate, di-iso-hexyl acid phosphate,
di-iso-heptyl acid acid phosphate, di-iso-octyl acid phosphate,
20 di-iso-nonyl acid phosphate and di-iso-decyl acid phosphate are
preferable; and
mono-n-octyl acid phosphate, di-n-octyl acid phosphate, di-iso-octyl
acid phosphate, and mixtures thereof are more preferable.
[0032] In the lubricant composition according to the present
25 embodiment, the content of the acidic phosphoric acid ester of the
component (B) is 0.01% by mass or more, more preferably 0.02% by
mass or more and more preferably 0.3% by mass or more, and 2% by
mass or less, more preferably 1% by mass or less and most preferably
0.8% by mass or less, based on the total amount of the composilion. If
the content is less than 0.01% by mass, antiwear performance is
5 insufficient. In addition, if the content is more than 2% by mass, the
antiwear performance improvement effect corresponding to the content
is not achieved, and such a case is not preferable in terns of economic
efficiency.
[0033] The sulfur compound of the component (C) is not particularly
10 restricted as long as characteristics of the lubricant composition are not
impaired, but sulhized oil and fat, a thiadiazole compound,
dihydrocarbyl polysulkide, sulfkrized fatty acids, s W i d olefins,
sulfide esters, a sulfurized mineral oil, a zinc dithiophosphate compound,
a zinc dithiocarbamate compound, a molybdenum dithiophosphate
15 compound, a molybdenum dithiocarbamate compound, an
alkylthiocarbarnoyl compound, a thiocarbamate compound, a
thioterpene compound and a dialkylthiopropionate compound are
preferably used.
[0034] The sulhrized oil and fat is one obtainable by reacting s u l k or
20 a sulfur-containing compound with oil and fat (lard oil, whale oil,
vegetable oil, fish oil and the like), and examples thereof include
sulfurized lard, a sulfurized rapeseed oil, a sulfurized castor oil, a
sulfirized soybean oil and a sulfirized rice bran oil.
LO0351 Examples of the thiadiazole compound include 1,3,4-thiadiazole
25 represented by the following general formula (3), a 1,2,4-thiadiazole
compound represented by the following general fonnula (4) and a
I,4,5-thiadiazole compound represented by the following general
formula (5):
wherein R3, R~,.R', R6, R~ and R* may be the same or different and each
represent a hydrogen atom or a hydrocarbon group having 1 to 20
carbon atoms, and a, b, c, d, e and f may be the same or different and
each represent an integer of 0 to 8.
10 [0036] Specific examples of such a thiadiazole compound preferably
include 2,5-bis(n-hexyldithi0)-1,3,4-thiadiazole,
2,5-bis(n-octy1dithio)-1,3,4-thiadiazole,
2,5-bis(n-nony1dithio)-l,3,4-thiadiazole,
2,5-bis(1,1,3,3-tetramethylbutyldithio)-1,3,4-thiadiazole,
15 3,5-bis(n-hexy1dithio)- 1,2,4-thiadiazole,
3,5-bis(n-octy1dithio)- 1,2,4-thiadiazole,
3,5-bis(n-nonyldithio)-1,2,4-thiadiazole,
3,5-bis(1,1,3,3-tetramethylbutyldithio)-1,2,4-thiadiazole,
4,5-bis(n-hexy1dithio)-1,2,3 -thiadiazole,
20 4,5-bis(n-octy1dithio)- 1,2,3-thiadiazole,
4,5-bis(n-nony1dithio)-1,2,3-thiadiazole,
4,5-bis(l,l,3,3-tetramethylbutyIdithio)-l,2,3-~hiadiazole, and mixtures
thereof.
[0037] Dihydrocarbyl polysulfide is generally a sulfur-based compound
5 called polysulfide or sulhrized olefin, and specifically means a
compound represented by the following general formula (6):
R~-s,-R" (6)
wherein IX9 and R'' may be the same or different and each represent a
linear or branched alkyl group having 3 to 20 carbon atoms, an aryl
10 group having 6 to 20 carbon atoms, an alkylayl group having 6 to 20
carbon atoms or an arylalkyl group having 6 to 20 carbon atoms, and x
represents an integer of 2 to 6, preferably an integer of 2 to 5.
[0038] R9 and R'' in the above general formula (6) specifically include
respective linear or branched aUryl groups of a propyl group, a butyl
15 group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a
nonyl group, a decyl group, an undecyl group, a dodecyl group, a
tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl
group, a heptadecyl group, an octadecyl group, a nonadecyl group and
an icosyl group;
20 ayl groups such as phenyl group and a naphthyl group; and
alkylaryl groups such as a tolyl group, an ethylphenyl group, a xylyl
group, an ethylmethylphenyl group, a diethylphenyl group, a linear or
branched propylphenyl group, a linear or branched butylphenyl group, a
linear or branched pentylphenyl group, a linear or branched hexylphenyl
25 group, a linear or branched heptylphenyl group, a linear or branched
octylphenyl group, a linear or branched nonylphenyl group, a linear or
branched decylphcnyl group, a linear or branched undecylphenyl group,
a linear or branched dodecylphenyl group, a di(1inear or
branched)propylphenyl group, a &(linear or branched)butylphenyl
group, a methylnaphthyl group, an ethylnaphthyl group, a linear or
5 branched propylnaphthyl group, a linear or branched butylnaphthyl
group, a dimethylnapl~thyl group, an ethylmethylnaphthyl group, a
diethylnaphthyl group, a di(linear or branched)propylnaphthyl group
and a di(1ineax or branched)butylnapl~thylg roup; and arylallcyl groups
such as a benzyl group, a phenylethyl group and a phenylpropyl group;
10 and all compounds include all isomers and structural isomers.
[0039] Among them, as R' and R'O in the general fomula (6), an alkyl
group having 3 to 18 carbon atoms, derived fiom propylene, 1-butene or
isobutylene, or an aryl soup, an alkylaryl group or an arylalkyl group
having 6 to 8 carbon atoms is preferable, and in particular, an -1
15 group having 3 to 18 carbon atoms, derived fiom propylene, 1-butene or
isobutylene is preferable. Examples of these groups include alkyl
groups such as an isopropyl group, a branched hexyl group derived from
a propylene dkner, a branched nonyl group derived from a propylene
trimer, a branched dodecyl group derived from a propylene tetramer, a
20 branched pentadecyl group derived from a propylene pentamer, a
branched octadecyl group derived eom a propylene hexamer, a
sec-butyl group, a tert-butyl group, a branched octyl group derived fiom
a 1-butene dimes, a branched octyl group derived from an isobutylene
dimer, a branched dodecyl group derived fiom a 1-butene trimer, a
25 branched dodecyl group derived from an isobutylene trimer, a branched
hexadecyl group derived from a 1-butene tekamer and a branched
hexadecyl group derived &om an isobutylene tetramer, aid all groups
include all branched isomers.
[0040] Furthermore, as K~ and R'' in the above general formula (6),
separately, a branched akjd group having 3 to 18 carbon atoms, derived
5 from ethylene or propylene, is more preferable and a branched alkyl
goup having 6 to 15 carbon atoms, derived &om ethylene or propylene,
is particularly preferable from the viewpoint of the improvement in
antiwear performance.
[004 11 Examples of the sulfurized fatty acid include oleic acid sulfide.
10 [0042] Examples of the sulfurized olefin include a compound
represented by the following general formula (7). This compound is
obtainable by reacting olefins having 2 to 15 carbon atoms or di- to
tetramers thereof with a sulhizing agent such as sulfur or sulfur
chloride, and as the olefins, propylene, isobutene, diisobutene and the
15 like are preferable:
R~~-S,-R~~(7 )
wherein R" represents an alkenyl group having 2 to 15 carbon atoms,
R ' ~rep resents an alkyl group or an alkenyl group having 2 to 15 carbon
atoms, and y represents an integer of 1 to 8.
20 [0043] Examples of the sulfide ester include animal and vegetable oils
and fats such as beef tallow, lard, fish fat, a rapeseed oil and a soybean
oil; unsaturated fatty acid esters obtainable by reacting unsaturated fatty
acids (including oleic acid, linoleic acid or fatty acids extracted &om the
above animal and vegetable oils and fats) with various alcohols; and
25 those obtainable by sulfurizing mixtures thereof by an arbitrary method.
More specific examples include methyl oleate sulfide, rice bean fatty
acid octyl sulfide, and mimes thereof.
COO441 The sulikrized mineral oil refers to one in which elemental
s u l k is dissolved in a mineral oil. Herein, the mineral oil for use in
the sulhized mineral oil in the present invention is not particularly
5 restricted, but any of those listed as the mineral oil of the base oil in the
invention of the present application may be used therefor. In addition,
as elemental s u l k one in the fonn of any of a mass, a powder, a
molten liquid and the Like may also be used, but elemental sulfur in the
form of a powder or a molten liquid may be preferably used because of
10 capable of being effectively dissolved in the base oil. The content of
sulfur in the sulfiriied mineral oil is not particularly restricted, but is
usually preferably 0.05 to 1.0% by mass and more preferably 0.1 to
0.5% by mass based on the total amount of the sulhized mineral oil.
[0045] The zinc dithiophosphate compound, the zinc dithiocarbamate
15 compound, the molybdenum dithiophosphate compound and the
molybdenum dithiocarbamate compound mean compounds represented
by the following general formulae (8) to (1 l), respectively:
wherein R13, lXI4, R'~,.R'~R,1 7, RL8R, 19, R20, RZ1R, Z2,R ~R~~R, '~ ~, R, ~ ~ ,
lXZ7 and R2' may be the same or different and each represent a
hydrocarbon group having one or more carbon atoms, and X' and x2
5 each represent an oxygen atom or a sulfur atom.
100461 Herein, specific examples of the hydrocarbon groups
represented by RI3, R'~, R16, R17, R", lXL9R, ZOR, "~ R ~R~~,R~ ~, ~ ,
R ~R~Z6,R, Z 7a nd R~~in clude, in addition to a methyl group and an ethyl
group, alkyl groups such as a propyl group, a butyl group, a pentyl
10 group, a hexyl group (including all branched isomers), a heptyl group,
an octyl group, a nonyl group, a decyl group, an undecyl group, a
dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group,
a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl
group, an icosyl group, a heneicosyl group, a docosyl group, a tricosyl
15 group and a tetracosyl group, all groups including all branched isomers;
cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group and a
cycloheptyl group;
al!lcycloalkyl groups such as a methylcyclopentyl group, an
ethylcyclopentyl. group, a dimethylcyclopentyl group, a
20 propylcyclopentyl group, a methylethylcyclopentyl group, a
tritnethylcyclopentyl group, a butylcyclopentyl group, a
methylpropylcyclopentyl group, a diethylcyclopentyl group, a
dimethylethylcyclopentyl group, a methylcyclohexyl group, an
ethylcyclohexyl goup, a dimethylcyclohexyl group, a propylcyclohexyl
group, a methylethylcyclohexyl group, a trimethylcyclohexyl group, a
butylcyclohexyl group, a methylpropylcyclohexyl group, a
diethylcyclohexyl group, a dimethylethylcyclohexyl group, a
methylcycloheptyl group, an ethylcycloheptyl group, a
5 dimethylcycloheptyl group, a propylcycloheptyl group, a
methylethylcycloheptyl group, a trimethylcycloheptyl group, a
butylcycloheptyl group, a methylpropylcycloheptyl group, a
diethylcycloheptyl group and a dimethylethylcycloheptyl group, all
groups including all substituted isomers and branched isomers;
10 aryl groups such as a phenyl group and a naphthyl group;
alkyla~yl groups such as a tolyl group, a xylyl group, an ethylphenyl
group, a propylphenyl group, a methylethylphenyl group, a
trimethylphenyl group, a butylphenyl group, a methylpropylphenyl
group, a diethylphenyl group, a diiethylethylphenyl group, a
15 pentylphenyl group, a hexylphenyl group, a heptylphenyl group, a
octylphenyl group, a nonylphenyl group, a decylphenyl group, an
undecylphenyl group, a dodecylphenyl group, a tridecylphenyl group, a
tetradecylphenyl group, a pentadecylphenyl group, a hexadecylphenyl
group, a heptadecylphenyl group and an octadecylphenyl group, all
20 groups including all substituted isomers and branched isomers; and
arylalkyl groups such as a benzyl group, a phenethyl group, a
phenylpropyl group (including all branched isomers) and a phenylbutyl
group (including all branched isomers).
[0047] Examples of the alkylcarbamoyl compound include a compound
25 represented by the following general formula (12):
v~l~eseiRn ~R~~', ,R~ ~a nd R~~m ay be the same or different and each
represent an alkyl goup having 1 to 20 carbon atoms, and g represents
an integer of 1 to 8.
5 [0048] Specific examples of such an alkylcarbamoyl compound
preferably include bis(diniethylthiocarbamoyl)monosulfide,
bis(dibutylthiocarbamoyl)monosulfide,
bis(dimethylthiocarbamoyl)disulfide,
bis(dibutylthiocarbamoyl)disulfide, bis(diamylthiocarbamoyl)disulfide,
10 bis(dioctylthiocarbamoyl)disulfide, and mixtures thereof.
[0049] Examples of the alkylthiocarbamate compound include a
compound represented by the following general foimula (13):
wherein R ~R. ~. ~,R~ 3* a,nd R~~m ay be the same or different and each
15 represent an alkyl group having 1 to 20 carbon atoms, and R~~
represents an allcyl group having 1 to 10 carbon atoms.
[0050] Specific examples of such an alkylthiocarbamate compound
preferably include metfiylenebis(dibutyfdithioc'arbamate) and
methylenebis[di(Z-ethylhexy1)dithiocarbamate.
20 [0051] Furthermore, examples of the thioterpene compound include a
reaction product of phosphorus pentasufide and pinene, and examples
of the dialkylthiopropionate compound include dilauryl thiodipropionate,
distearyl thiodipi-opionate, and mixtures thereof.
[0052] in the present embodiment, when at least one selected from the
group consisting of the sulfurized oil and fat, the thiadiazole compound
and dihydrocarbyl polysulfide among the above sulhr compounds is
5 used, such a case is preferable because the wear-resistant characteristic
improvement effect is achieved at a higher level, and it is more
preferable to use further the sulfurized oil and fat.
[0053] In the lubricant composition according to the present
embodiment, when the component (C) is a sulfur compound other than
10 the thiadiazole compound, the content thereof is 0.5% by mass or more
and more preferably 0.7% by mass or more, and 5% by mass or less and
more preferably 3% by mass or less, based on the total amount of the
composition. If the content is less than 0.5% by mass, antiwear
performance is insufficient, and if the content is more than 2% by mass,
15 the antiwear performance improvement effect corresponding to the
content is not achieved, and such a case is not preferable in terms of
economic efficiency.
[0054] In addition, when the component (C) is the thiadiazole
compound, the content thereof is 0.05% by mass or more and more
20 preferably 0.1% by mass or more, and 1% by mass or less and more
preferably 0.5% by mass or less, based on the total amount of the
composition. If the content is less than 0.05% by mass, antiwear
performance is insufficient, and if the content is more than 1% by mass,
the antiwear performance improverncnt effect corresponding to the
25 content is not achieved, and such a case is not preferable in terms of
economic eficiency.
[0055] It is possible to blend to the lubricant composition according to
the present embodiment an additive known in the lubricant field in order
to enhance the performance of the lubricant composition and to impart,
to the lubricant composition, performances necessary for the lubricant
5 composition, in particular, a lubricant composition for a slidii surface
of a machining tool.
[0056] Examples of such an additive include antioxidants such as
monohydric alcohols or polyhydric alcohols, monobasic acids or
polybasic acids, esters of the alcohols and the acids, phenolic
10 compounds such as di-tee-butyl-p-cresol and bisphenol A, and
amine-based compounds such as phenyl-a-naphthylamine and
N,N'-di(2-naphthy1)-p-phenylenediamine;
anti-wear agents such as a sulfur-containing phosphoric acid ester
compound;
15 oiliness agents such as esters, carboxylic acids and aliphatic alcohols;
metal deactivators such as benzotriazole;
anti-foaming agents such as a silicone oil and a fluorosilicone oil;
anti-corrosion additives such as akenylsuccinic acids and sorbitan
monooleate;
20 pour-point depressants such as polymethacrylate;
viscosity index improvers such as polybutene, polyallcylstyrenes, an
olefin copolymer, a styrene-diene copolymer and a styrene-maleic
anhydride copolymer; and
oil film-retaining agents of olefin-based polymers such as an
25 ethylene-propylene copolymer, polybutene and polyisobutylene.
[0057] The lubricant composition according to the present embodiment
is excellent in antiwear performance. Accordingly, the lubsicant
composition according to the present embodiment is vely useful in
terms of stabilization of operation of a machining tool, working
accuracy and the Like. In addition, the lubricant composition according
5 to the present embodiment is vely usehl because of being capable of
suppressing the increase in liquid leakage due to wear occurring in a
hydraulic pump and maintaining pump efficiency. Fcufhelmore, the
lubricant composition according to the present embodiment may be
suitably used in various applications in which antiwear performance is
10 required. In particular, in the case where the lubricant composition is
used as a lubricant for a slideway surface (sliding scu-face) of a
machining tool or the like, the above effect is fitsfher exerted. In
addition, even in the case where the lubricant composition is used as a
hydraulic oil, the above effect is hsther exerted.
15 Examples
[0058] Hereinafter, the present invention will be more specifically
described based on Examples and Comparative Examples, but the
present invention is not limited to these Examples at all.
[0059] pxamples 1 to 16, Comparative Examples 1 to 71
20 In Examples 1 to 16 and Comparative Examples 1 to 7, lubricant
compositions each having composition shown in Tables 1 to 4 were
prepared. Components used in preparation of each of the lubricant
compositions are as follows.
[0060] Lubricant base oil
25 Base oil 1: solvent-dewaxed and hydrorefined para&ic mineral oil
(kinematic viscosity at 40°C: 68.8 d s ; viscosity index: 98; sulfur
contcnt 0.62% by mass)
Base oil 2: synthetic lubrication base material (number average
molecular weight: 3700; kinematic viscosity at 100°C: 2000 d s ;
viscosity index: 300; sulfur content: less than 0.1% by mass)
5 Component (A): phosphoric acid ester
Al: fri(2-ethylhexy1)phosphate
A2: tricresyl phosphate
A3: tri(isopropylary1)phosphoric acid ester represented by the following
general formula (14)
wherein i-Pr represents an isopropyl. group and n represents a mixture of
1 to3.
Component @): acidic phosphoric acid ester
B 1 : n-butyl acid phosphate
15 B2: n-octyl acid phosphate
B3: 2-ethylhexyl acid phosphate
B4: oleyl acid phosphate
B5: eicosa acid phosphate
B6: docosa acid phosphate (mixture of linear and branched ones)
20 Component (C): sulfur compound
C1: sulfirized oil and fat
C2: 2,s-bis(1,1,3,3-tetramethylbuty1dithio)- 1,3,4-thiadiazole
C3: di-tert-dodecyl polysulfide
[0061] Then, each of the lubi-icant compositions in Examples 1 to 16
and Comparative Examples 1 to 7 was subjected to the following test.
The evaluation of lubricity was according to ASTM D3233-93
(Falex PN test) and the abrasion wear (mg) was measured. The
obtained resultsare shown in Tables 1 to 4. Herein, "Fractued" in
Table 4 means breakage such as bending or twisting of P (pin).
CLAlMS
[Claim 1]
A lubricant composition for a machining tool, containing:
lubricant base oil; and,
5 based on a total amount of the composition,
0.05 to 5% by mass of a phospl~oric acid ester represented by the
following general fo~mula(1 ):
@'o)~P=o (1)
wherein R' represents any of an my1 group having 6 to 15 carbon atoms
10 and a saturated hydrocarbon group having 1 to 20 carbon atoms, and
each R' may be the same or different;
0.01 to 2% by mass of an acidic phospho~5c acid ester represented by
the following general formula (2):
@2~)n~(~O)(OI-1)~~(-2n) ~
15 wherein R2 represents an alkyl group having 4 to 20 carbon atoms, n
represents I. or 2, and each R2 may be the same or different; and
0.5% by mass to 5% by mass of a sulfur compound.
[Claim 2]
The lubricant composition for a machining tool according to
20 claim 1, wherein R~ in the general formula (2) represents an alkyl group
having 8 carbon atoms.
[Claim 3]
The lubricant composition for a machining tool accordimg to
claim 1, wherein R' in the general formula (1) represents a saturated
25 hydrocarbon group having 1 to 20 carbon atoms.
[Claim 4]
The lubricant composition for a machining tool according to
claim 1, which simultaneously lubricates a slideway surface and a
hydraulic pump of a machining tool.