Title of Invention: LUBRICANT BASE OIL, REFRIGERATOR OIL
ANJ WORKING FLUID COMPOSITION FOR REFRIGERATORS
Technical Field
5 [0001] The present invention relates to a lubricating base oil, a
reEgerating machine oil and a working fluid composition for a
rekigerating machine.
Background A1-i
[0002] in the refrigerationlair-conditioning field, 1 ,I $1,2-
10 tetrafluoroethane @134a), R410A as a mixed refrigerant of
difluoromethane (R2.2) and pentafluoroethane (R125) in a mass ratio of
111, and the Eke, which are hyd*onuorocarbons @PC), are currently
widely used as refrigerants for coolerators, car air-conditioners, room
air-conditioners, i n d d a l refrigerators, and h e Like.
15 [0003] These IlFC reeigemts, however, have a high global warming
potential (GW) of 1000 or more while having an ozone depletion
potential (ODP) of zero, and thus the use thereof comes to be limited by
the so-called P-gas regulation for the purpose of global environment
protection.
20 [0004]As alternatives of the refrigerant high in GWP,
2,3,3,3-teetrafluoropropene @FO-1234yf) and difluoromethane (l732)
itself have been studied as candidates in terns of their thermodynamic
characteristics. In addition, a mixed refiigerant of such a reeigeranl
and other reEgerant, which is well-balanced with respect to GWP and
25 various characteristics, has also been studied. An alternative of the
HFC refiigerant is required to be low in GWP, and the GWP of
HFO-1234yf is as low as 4. Although the GWP of R32 is as slightly
high as 675, R.2 has been studied as a major candidate because the gas
pressure thereof is high and R32 is a highly-effective refi-igerant (for
example, Patent Literature 1).
5 [0005] In addition, hydrocarbon refrigerants such as isobutme (R600a) I ' /
and propane ($2901, which have been already in practical use for
coolerators, have been studied as alternative refiigerants while they are
flammable, because the GVJP is as low as 20 or less and physical
property values are suitable.
10 [0006] When a reeigerant whose pressure is high, such as R32 or a
mixed refrigerant including R32, among alternative reliigerant
candidates, is used, the discharge temperature in a compressor is higher,
thus the oil film of a refrigerating machine oil for lubricating the inside
of the compressor is thinner and lubricating conditions are severer, and
15 therefore a reftigerating machine oil good in lubricity and stability is
required.
[0007] In addition, in the case of the hydrocarbon refrigerant, not only
fluorine that results in an increase in lubricity is not present in the
hydrocarbon molecule and thus the refrigerant cannot be expected to
20 exert the lubricity enhancement effect unlike the NFC refrigerant and
the like, but also the solubility of the hydrocarbon refrigerant in the
refigerating machine oil is high t~ reduce the viscosity of the oil,
thereby making lubricating conditions severer, and it is demanded for
the reEigerating machine oil that its antiwear property is equal to or
25 higher than that of a conventional ono.
Citation List
Patent Literature
[0008j [Patent Literature 11 Japanese Patent Application Laid-Open No. 1
Summary of Invention
Technical Problem
[0009] The present invention is aimed at providing a lubricating base
oil that is large in the effect of antiwear and also good in stability and
excellent in long-term. reliability even under severe lubricating
conditions as compared with a conventional lubricating base oil, as well
as a refrigerating machine oil and a working fluid composition for a
refrigerating machine, using the lubricating base oil.
Solution to Broblcm
[0010] The present inventors have found that a lubricating base oil
containing a complex ester synthesized %om specific polyhydric
alcohol, polybasic acid, diiydric alcohol and monohydric alcohol is
high in antiwear property and good in stability, and can be sta,bly used
over a long period, thereby leading to the completion of the present
invention.
[0011] That is, the present invention provides lubricating base oils
according to the following [1] to [7], refsigerating machine oils
according to the following [a] to [14], and a workhg fluid composition
for a refiigerating machine according to the following [15].
[I] A lubricating base oil comprising an ester synthesized from: a first
component that is at least one selected from polyhydric alcohols having
2 to 4 hydroxyl goups; a second component that is at least one selected
from polybasic acids having 6 to 12 carbon atoms; and a thisd
component that is at least one selected from monohydric alcohols
having 4 to 18 caibon atoms and monocarboxylic acids having 2 to 12
carbon atoms.
[2] The lubricating base oil according to [I], wherein the first
5 component comprises at least one selected from neopentyl glycol,
trimethylolpropane and pentaerythritol.
[3] The lubricating base oil according to [1] or [2], wherein the thest
component comprises a first alcohol that is at least one selected from
neopentyl glycol, trimethylolpropane and pentaerythritol, and a second
10 alcohol that is at least one selected horn dihydric alcohols having 2 to
10 carbon atoms other than neopenty1 glycol.
[4] The lubricating base oil according to any one of [I] to [3], wherein
the &st component comprises at least one selected from neopentyl
glycol and trimethylolpropane.
15 [51 The lubricating base oil according to any one of [I] to [4], wherein
the second component comprises at least one selected fiorn adipic acid
and sebacic acid
[6] The lubricating base oil according to any one of [I] to [5], wherein
the first component comprises butanediol.
20 [7] The lubricating base oil according to any one of [I] to [6], wherein
the third component comprises at least one selected horn monohydric
alcohols having 8 to 10 carbon atoms.
[8] A refrigerating machine oil comprising the lubricating base oil
according to any one of [I] to [7].
25 [9] The refrigerate machine oil according to [8], being used with a
refrigerant comprising at least one selected from hydrofluorocarbons,
hydrofluoroolefms, hydrocarbons having 2 to 4 carbon atoms, and
carbon dioxide.
[lo] The refrigerating machine oil according to [8] or [9], being used
I: with a refrigerant having a global warming potential of 1000 or less.
i 5 [ll] The refrigerating machine oil according to any one of [8] to [lo],
i
,I being used with a refkigerant having a global warming potential of 700
or less.
[I21 The refiigeratiilg machine oil according to any one of [8] to [Ill,
being used with a refkigerant comprising difluoromethane.
10 [13] The refrigerating machine oil according to any one of claims 8 to
12, bcing used with are%gerant comprising propane or isobutane.
[14] The refiigerating machine oil according to any one of IS] to [12],
being used with a refrigerant comprising at least one
hydrofluoropropene.
15 11.51 A working fluid composition for a refrigerating machine,
comprising: a refiigerating machine oil comprising the lubricating base
oil according to any one of [I] to [7]; and a rei?igerant comprising at
least one selected from hydrofluorocarbo~~sh, ydrofluoroolefins,
hydrocarbons having 2 to 4 carbon atoms, and carbon dioxide.
20 Advantageous Effects of Invention
[0012] The lubricating base oil, refrigerating machine oil and working
fluid composition for a refiigerating machine of the present invention
exert remarkable effects so that they are high in antiwear property and
good in stability as well as allow reEgemtion1air-conditioning
25 equipment to be stably used over a long period, even under severe
lubricating conditions, as compared with conventional lubricating base
oil, reeigerating machine oil and working fluid composition for a
reftigerating machine.
Description of Embodiments
[0013] Hereinafter, suitable embodiments of the present invention are
5 described in detail.
[0014] First embodiment: Lubricating base oil]
A lubricating base oil according to a first embodiment of the
present invention contains an ester (hereinafter, sometimes also referred
to as "complex ester according to the present embodiment") synthesized
10 &om a first component, a second component and a third component
shown below:
first component: at least one selected hom polyhydric alcohols having 2
to 4 hydroxyl groups,
second component: at least one selected &om polybasic acids having 6
15 to 12 carbon atoms, and
lhird componenk at least one selected from monohy&tc alcohols having
4 to 18 carbon atoms and monocarboxylic acids having 2 to 12 carbon
atoms.
[0015] Herein, the tcnns "first componen.t", "second component" and
20 "third component" are conveniently collective terms, and the
compound(s) included in each of the components may be one
compound, or two or more compo~~nds.
[0016] The frst component contains at least one selected fiom
polyhydris alcohols having 2 to 4 hydroxyl groups. Examples of such
25 polyhydric alcohols include neopentyl glycol, trimethylolpropane and
pentaeryhitol, and also dihydric alcohols having 2 to 10 carbon atoms
other than neopentyl glycol.
[0017] It is preferable that the first component contain at least one
polyhydric alcohol (hereinafter, sometimes also referred to as "(A)
component") selected &om neopentyl glycol, trirnethylolpropane and
pentaerythritol. The (A) component can be used as the first component
to thereby impart viscosity suitable as a base oil to the resulting ester, as
compared with the case where the (A) component is not used. In the
case where at least one selected from neopentyl glycol and
trimethylolpropane is here used as the (A) component, viscosity can be
lowered and more excellent low-temperatwe characteristics can be
achieved as compared with the case where pentaerythritol that is a
tetrahydric alcohol is used. Furthermore, in the case where neopentyl
glycol is used, viscosity can be widely adjusted, and such a case is more
preferable.
[IN181 In addition, it is preferable that the &st component contain the
(A) component and dihydric alcohol(s) having 2 to 10 carbon atoms
other than neopentyl glycol (hereinafter, sometimes also referred to as
"(B) component"). The @) component can be used to thereby enhance
the lubricity or the resulting ester as compared with the case where the
(B) component is not used. Examples of the (B) component include
ethylene glycol, propanediols, butanediols, pentanediols, hexanediols,
2-methyl-1,3-propanediol, 3-methyl-1,5-penkmediol and
2,2-diethyl-1,3-pentanediol. Butanediols, in which the characteristic
balance of the base oil synthesized is good, are preferable, and examples
thereof include 1,2-butanediol, 1,3-butmediol, 1,4-butanediol and
2,3-butanediol, but I ,3 -butanediol and I ,4-butanediol are more
preferable in terms of characteristics.
[0019] The second component contains at least one selected fkom
polybasic acids having 6 to 12 carbon atoms (hereinafter, sometimes
also referred to as "(C) component"). Such polybasic acids include
5 adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,
phthalic acid and trimellitic acid. Adipic acid and sebacic acid, which
are well balanced with respect to the lubricity and the stability of the
resulting base oil md are available, are: preferable, and among them,
adipic acid is more preferable.
10 [0020] The third component contains at least one selected &om
monohydric alcohols having 4 to 18 carbon &oms and monocarboxylic
acids having 2 to 12 carbon &oms.
[0021] Examples of such monohydric alcohols having 4 to 18 carbon
atoms (hereinafter, sometimes also referred to as "@) component")
I5 include butanols, pentanols, heptanols, octanols, nonanols, decanols,
dodecanols and oleyl alcohols. These monohydric alcohols may be
either linear alcohols or branched alcohols. Monohydric alcohols
having 8 to 10 carbon atoms are preferable, and among hem,
2-ethylhexanol that is a branched octanol and 3,5,5-trimethylhexanol
20 that is a branched nonanol are preferable in terms of good
low-temperature characteristics of the complex ester synthesized.
COO223 Specific examples of such monocarboxyiic acids having 2 to 12
carbon atoms (hereinafter, sometimes also referred to as "(E)
component") include acetic acid, propanoic acids (also referred to as
25 propionic acids), linear or branched butanoic acids, linear or branched
pentamic acids, lii~earo r branched hexanoic acids, linear or branched
I
heptanoic acids, linear or branched octanoic acids, linear or branched I
I
nonanoic acids, linear or branched decanoic acids, linear or branched
undecanoic acids, and linear or branched dodecanoic acids. As the (E)
component, a- andlor P-branched fatty acids are preferable, isobutanoic
5 acid, 2-methylbutanoic acid, 2-methylpentamic acid, 2-methylhexanoic
acid, 2-ethylpentanoic acid, 2-methylheptanoic acid, 2-etl~ylhexanoic
acid, 3,5,5-trimethylhexanoic acid and the like are preferable, and
among them, 2-elhyhexanoic acid andlor 3,5,5-trimethylhexanoic acid
is particularly preferable.
10 [0023] Examples of a preferable mode of the complex ester according
to the present embodiment include an ester synthesized &om
(A) a fM alcohol that is at least one selected hom neopentyl glycol,
trimethylolpropane and pentaeryhitol,
(l3) a second alcohol that is at least one selected fiom dihydric alcohols
15 having 2 to 10 carbon atoms other than neopentyl glycol,
(C) at least one polybasic acid selected from polybasic acids having 6 to
12 carbon atoms, and
(D) a third alcohol that is at least one selected from monoalcohols
having 4 to 18 carbon atoms.
20 [0024] The method for synthesizing the complex ester according to the
present embodiment is not particularly l i t e d . Examples of a
preferable method for sylthesizing the ester from the above components
(A) to (D) include the fol'ollo~ving.
First, the (A) component, the (B) component and the (C)
25 camponent are reacted to obtain a first ester intermediate. The molar
ratio of the (A) component, the (l3) component and the (C) component
is here adjusted such that the carboxylic acid group (-COOH) derived
from the (B) component is present in the resulting Grst ester
intermediate.
Then, the above first ester intermediate and the @) component
5 are reacted to esterify the carboxylic acid group (-COOH) of the Grst
ester intermediate with the @) component (monohydric alcohols having
4 to 18 carbon atoms) io obtain the intended ester (the complex ester
according to the present embodiment).
The esterification reaction in each of the steps can be performed
according to a conventional method, and the reaction condition of the
esterification reaction can be appropriately selected.
[0025] Herein, in the case of a complex ester including monobasic
acid(s) as a constituent component (the molar mtio of the polybasic acid
to the polyhydric alcohol is adjusted to allow an ester intermediate in
which the hydroxyl group of the alcohol remains, and the hydroxyl
group is esterified with a monocarboxylic acid), the es.ter may cause a
relatively strong acid by hydrolysis when used as a refrigerating
machine oil, and stability may be insufficient, On the contrary, the
ester synthesized &om the (A), (B), (C) and (D) components contains no
monocarboxylic acid as a constituent component, and thus has a higher
stability than a complex ester containing it as a constituent component.
[0026] The complex eater according to the present embodiment can be
suitably used as a base oil of a reeigerating machine oil that is a
lubricant of a refrigeratiodair-conditioniug refrigerating machine.
Herein, as described later, a rekigerating machine oil according to the
present embodiment can M e r contain a base oil other than the
I
!
complex according to the present embodiment, and various additives.
[0027] [Sccond embodiment: Refrigerating machine oil]
A refrigerating machine oil according to a second embodiment
of the present invention contains an ester synthesized from a first
5 alcohol that is at least one selected from neopentyl glycol,
trimethylolpropane and pentaerythritol, a polybasic acid that is at least
one selected from polybasic acids having 6 to I2 carbon atoms, a
second alcohol h i t is at least one selected %om dihydric alcohols
having 2 to 10 carbon atoms other than neopentyl glycol, and a third
10 alcohol that is at least one selected from monohydric alcohols having 4
to 18 carbon atoms (hereinafter, sometimes also referred to as " the
complex ester according to the present embodiment"). Herein, the
complex ester is the same as the complex ester according to the first
embodiment, and thus explanation overlapped is here onnitted.
15 [0028] l'he refrigelating machine oil according to the present
embodient may be one made of only the complex ester according to
the present embodiment (namely, the content of the complex ester
according to the present embodiment is 100% by mass based on the
total amount of the refrigerating machine oil), and may M e r contain a
20 lubricating base oil and/ or additive other than the complex ester
according to the present embodiment.
[0029] In the case where the refrigerating machine oil according to the
present embodiment kther contains a lubricating base oil andl or
additive other than the complex ester according to the present
25 embodiment, the content of the complex ester is preferably 10% by
mass or more, more preferably 20% by mass or more and mher
prererably 30% by mass or more based on the total amount of the
reeigerating machine oil.
[0030] Examples of the lubricatjllg base oil other than the complex
ester according to the present embodiment include a mineral oil type
base oil, and a synthetic base oil other than the complex ester according
to the present embodiment.
100311 The refrigerating machine oil according to the present
embodiment can cantain additives such as an antioxidant, a friction
modifier, an antiwear additive (icIuding an anti-wear agent and
extreme pressure agent), an antirust agent, a metal deactivator and an
antifoamer in order to further enhance performmces, as long as the
object of the present invention is not impaired.
[0032] For example, the antioxidant indudes a phenolic compound
such as di-tert-butyl-p-cresol, and an mine type compound such as
alkyl diphenylamine, the fiction modifier includes aliphatic amines,
aliphatic amides, aliphatic irnides, alcohols, esters, acidic phosphate
amine salt and phosphite mine salt, the anti-wear agent includes zinc
diallcyldithiophosphate, the extreme pressure agent includes sulhized
olefins and sulfurized oils and fats, the antirust agent includes allcenyl
succinate or partial esters, the metal deactivator includes benzotriazoie,
and the antifoamer includes a silicone compound and a polyester
compound, respectively.
[0033] Ln addition, in order to further enhance antiwear property of the
retiigerating machine oil according to the present embodiment, it is
possible to apply an antiwear additive. Examples of a preferable
antiwear additive include phosphates, and among them, examples of a
preferable compound include triphenyl phosphate (TPP), tricresyl
phosphate QCP), and alkylphenylphosphates having an alkyl group
having 3 to 4 carbon atoms (APPs). TPP and TCP each have a single
structure. On the other hand, AF'Ps are each usually a mixture of APP
5 having one alkylphenyl group (mono-type), APP having two
alkylphenyl groups (di-type) and APP having three alkylphenyl groups
(tri-type), but the mixing ratio thereof is not particularly limited. In
terms of the enhancement effect of antiwear property, and stability, the
content of the antiwear additive is preferably 0.1 to 3.0% by mass based
10 on the total amount of the refrigerating machine oil.
LO0341 In addition, a suitable sulfur type additive is a sulfide compound.
There are many types of sulfide compounds, but among them, a
monosuEde compound is preferable. Herein, for example, a sulfur
compound whose activity is high, such as a disuEde compound, may
15 cause stability of the refkigerating macyme oil to be deteriorated and
may cause copper often used in the inside of refrigeration equipment to
be converted. As the suEde compound, in particular, a thiobisphenol
compound that has antioxidizing, namely, radical scavenging ability and
that is a stabilizer is preferable. The antiwear effect thereof is
20 comparable with that of phosphates. The content of the sulfide
compound is preferably 0.05 to 2.0% by mass based on the total amount
of the refrigerating machine oil. If the content is less than 0.05% by
mass, the effect of adding the sulfide compound may be inslafftcient.
In addition, if the content is more than 2.0% by mass, corrosive wear
25 may be conversely caused depending on the atmosphere.
[00351 The kinematic viscosity at 40°C of the rekigerating machine oil
according to the present embodiment is preferably 3 to 500 mm2/s, more
preferably 3 to 300 mm2/s and further preferably 5 to 150 mm2/s.
[0036] The pour point of the refrigerating machine oil according to the
present embodiment is preferably -10°C or lower and more preferably
-20°C or lower. In addition, from the viewpoint of lubricity, the pour
point is preferably -55OC or higher.
[0037] The acid value of the refrigerating machine oil according to the
present embodiment can be preferably 0.1 mgKOHg or less and more
preferably 0.05 mgKOWg or less in order to prevent corrosion of a
metal used in a refkigeratiug machine or pipe and suppress degradation
of the refi-igerating machine oil itself. Herein, the acid value in the
present invention means an acid value measured according to
"petroleum products and lubricants-neutralization test method" in JIS
K2501.
[0038] The viscosity index and the flash point of the re%gerating
machine oil according to the present embodiment are not particularly
limited, but the kinematic viscosity is preferably 10 or more, and the
flash point is preferably 120°C or higher and more preferably 200°C or
higher. In addition, the moisture content of the refrigerating machine
oil according to the present embodiment is also not limited, but is
preferably 200 ppm or less, Inore preferably 100 ppm or less and most
preferably 50 ppm or less. ILn particular, in the case where the
refrigerating machine oil is used in a closed type retiigerating machine,
it is demmded that the moisture content be low hom the viewpoints of
stability and electrical insukttion property of the rehigerating machine
oil.
[0039] The refrigerating machine oil accordiing to the present
embodiment can be used together with various refrigerants. In other
words, according to the present embodiment, a working fluid
composition for a refrigerating machine, containing the reftigerating
5 machine oil according to the present embodiment and a refrigerant is
provided. In particular, the refrigerating machine oil according to the
present embodiment can exert an excellent effect in the case of being
used together with G refrigerant low in GWP.
[0040] The refiigerant is here described in detail: in the case of a
10 refrigerating machine, as described above, a HFC refrigerant currently
used, which is high in GWP, tends to be transferred to a refrigerant low
in GWP Bom Wle viewpoint of global warming prevention, and a
refrigerating machine oil to be adapted thereto is demanded.
j Currently, 1,1,1,2-tetrduoroethanes @FC-l34a, R134a) are
15 widely used for coolerators and car air-conditioners, and R410Athat is a
mixed refrigerant of difluoromethanes (i flFC-32, R32) and
pentafluoroethanes (WC-125, R125) in a mass ratio of 111 is widely
used for room air-conditioners, respectively. It has been considered
that, as the base oil of a refrigerating machine oil for a refrigerating
20 machine in which these refrigerants are used, esters (however, not
including the complex according to the present embodiment),
polyethers, in particular, polyol esters, polyallcylene glycols, and
polyvinyl ethers are suitable. The reason for this is because, in the
refrigerant circulation cycle of refiigemtionlair-conditioning equipment,
25 a refrigerating machine oil for lubricating a compressor circulates
together with a refiigerant in the cycle, and thus the refrigerating
machine oil is demanded to be compatible with the refrigerant. If the
refrigerating machine oil is not compatible with the refrigerant, the
reffigerating machine oil discharged from the compressor is easily
retained, and as a result, there occur the problems of wear due to
5 lubrication failure by reduction in the amount of the oil in the
compressor and blockage of an expansion mechanism such as a
capillary.
[0041] Each of the above refigerants, however, whose GWP is as high
as 1000 or more, and thus the use thereof is expected to be limited by
10 the so-called F-gas regulation. Then, as an alteinative thereof,
hydrofluoroolofins (EIPOs) and difluorometbane (R32) that are
unsaturated hydro£luorocarbons low in GW, or hydrocarbon
refrigerants such as propane (R290) and isobutane (R600a), and a mixed
rekigerant including them are studied, and are major candidates.
15 [0042] Examples of the unsahated hydrofluorocarbons include
2,3,3,3-tetrafluoropropene (IGO-1234fi, 1,3,3,3-tetrafluoropropene
(EXPO-1234ze) and 1,2,3,3,3-pentafluoropropene w0-1225ye).
These HFO refrigerants each have an easily degradable olefin strtxcture
in the molecule, and Urus are characterized by being poor in stability
20 while being low in GWP. In particular, decomposition of the
refrigerant together with wearing may be promoted by local heat
generation in a sliding portion due to metdmetal contact lmder severe
lubricating conditions, leading to degradation of a worlcing fluid in
which the re&gerant is compatible with the refrigerating machine oil,
25 and lubricity of the refrigerating machine oil is an extremely important
property.
100431 Jn addition, in the case of R32 that is hydrofluorocarbon (FIFC) I
low in boiling point and high in pressure, or a mixed refrigerani
including R32 in a lWge amount, the discharge temperature of the
compressor is increased and thus the oil film of the refrigerating
5 machine oil is thinner, making lubricating conditions severer. In
addition, in the case of a hydrocarbon refrigerant such as propane
(R290), fluorine that contributes to an enhancement in lubricity is not
present in the hydrocarbon molecule and the solubility in the
refrigerating machine oil is high to thereby reduce the viscosity of the
10 resgerating machine oil, making lubricating conditions severer. Each
of such refrigerant candidates low in GWP is under severe conditions
from the viewpoint of lubricity, and thus a rekigerating machine oil to
be used is demanded to be high in lubricity.
100441 The refrigerating machine oil according to the present
15 embodiment is sufficiently provided with the above characteristics
demanded, and can be used together with various refrigerants.
[0045] The refrigerating machine oil according to the present
embodiment is preferable as a refrigerating machine oil for refrigerants,
containing at least one selected kom hydrofluorocarbons (WCs),
20 hydrofluoroolefhs (EILFOs), hydrocarbons having 2 .to 4 carbon atoms
(HC) and carbon dioxide (COz). Jn addition, the refitgerating machine
oil is preferable for a refrigerant having a global warming potential
(GWP) of 1000 or less, and further preferable for a refrigerant having a
GWP of 700 or less.
25 [0046] Examples of the HFC refrigerant include hydrofluorocarbons
having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specific
examples include trifluoromethane @FC-23), pentafluoroethane i
(HFC-125), 1,1,2,2-tetrafluoroethane (ITFC-134),
I
1,1,1,2-tetrafluoroethme (HFC-134a), 1,1,1-trifluoroethane i: ,I
7 1
(HFC-143a), 1,l-difluoroethane @PC-1 52a), fluoroethane (HFC-161), I
5 1,1,1,2,3,3,3-heptafluoropropane( lWC-227ea),
1,1,1,2,3,3-hexduoropropane (I-IFC-236ea),
1,1,1,3,3,3-hexafluoropropane (f-IFC-236fa),
1,1,1,3,3-penhfluorapropane (I-XFC-245fa) and
1 ,I, 1,3,3-pentduorobutane(HFC-365mfc), or mixtures of two or more
10 of them. These refrigerants are appropriately selected depending on its
application and requirement performances, but preferable examples
include HFC-32 itself; HFC-23 itself; HFC-134a itself; HFC-125 itsee
a mixture of NFC-134alHFC-32 = 60 to 80% by mass140 to 20% by
mass; a mixture of HFC-32flIFC-125 = 40 to 700% by mass160 to 30%
15 by mass; a mixture of IFC-125HFC-143a = 40 to 60% by mass160 to
40% by mass; a mixture of HFC-134a/HFC-32flIFC-12=5 60% by
mass/JO% by mass/10% by mass; a mixture of
HFC-134d€PC-32&IECG125 = 40 to 70% by mass115 to 35% by
massf5 to 40% by mass; and a mixture of
20 XIFC-125MFC-134a/HFCc143a = 35 to 55% by mass11 to 15% by
mass140 to 60% by mass. Further specific examples include a mixture
of HFC-134aEFC-32 = 70130% by mass; a mixture of
HFC-32MFC-125 = 60140% by mass; a mixture of I3iFC-32/HFC-125 =
50150% by mass (R410A); amixture ofHFC-32EFC-125 = 45155% by
25 mass @410B); a mixture of HFC-125/NFC-143a = 50150% by mass
(R507C); amkture of HFC-32/HFC-125/KFC-134a = 30/10/60% by
mass; a mixture of IIFC-32~C-I25~C-l34=a 2 3125152% by mass
(R407C); a mixture of HFC-32/HFC-l25/HFC-l34a = 2511 5160% by
mass (R407J3); and a mixture of HFC-125/I-IFC-134&iFC-l43a =
4414152% by mass (R404A).
[0047] As the unsaturated hyciroduorocarbon (WO) reEgerant,
fluoropropenes having 3 to 5 fluorine atoms are preferable, and any one
of 1,2,3,3,3-pentafluoropropene OJFO-1225ye),
1,3,3,3-tetrafluoropopene @EO-1234ze), 2,3,3,3-.tetrafluoropropene
(I-IFO-1234yf), 1,2,3,3-tetrafluoropropene @PO-1234ye) and
3,3,3-Lrifluoropropenc (IPO-124320, or a mixture of two or more of
them is preferable. From the viewpoint of physical properties of the
refkigerant, one selected &om HFO-1225ye, HFO-1234ze and
HFO-1234yf, or two or more selected therefrom is preferable.
[0048] Examples of hydrocarbon refrigerants having 2 to 4 carbon
atoms include ethylene, ethane, propylene, propane @290),
cyclopropane, n-butane, isobutane, cyclobutane, methylcyclopropane or
a mixture of two or more of them. Among them, one that is gaseous at
25OC and 1 atm is preferably used, and propane, n-butane, isobutane,
2-methylbutane or a mixture thereof is preferable.
Examples
[0049] Hereinafter, the present invention is W e r specifically
described based on Examples and Comparative Examples, but the
present invention is not liited to the following Examples at all.
[0050] pxample 1: Production of ester (A-l)]
Neopentyl glycol, 1,4-butanediol and adipic acid were reacted in
neopentyl gtycol/l,4-butanediol/adipica cid = 110.3J2.4 (molar ratio) to
obtain an ester intermediate. 3,5,5-Trimethykiexanol was fivther
reacted with this ester intermediate in neopentyl
glycol/3,5,5-trimethylhexanol = 112.5 (molar ratio) using neither a
catalyst nor a solvent, and the remainkg alcohol was removed by
5 distillation. Then, an adsorption treatment (clay treatment) was
performed in the final step to remove traces of impurities, obtaining an
ester (kinematic viscosity at 40°C: 67.8 mm2/s, viscosity index: 145,
pour point: -50°C, hereinafter, referred to as ester (A-1)).
[0051] [Example 2: Production of ester (A-211
10 Neopentyl glycol, 1,3-butanediol and sebacic acid were reacted
in neopentyl glycol/l,3-butanediol/sebacica cid = 1/0.2!2.4 (molar ratio)
to obtain an ester intermediate. n-Odanol was further reacted with this
ester intermediate using neither a catalyst nor a solvent so that the ratio
of neopentyl glycoVn-ocianol was 112.6 (molar ratio), ahdthe remaining
15 alcohol was removed by distillation. Then, an adsorption treatment
(clay treatment) was performed in the final step to remove traces of
impurities, obtaining an ester (kinematic viscosity at 40°C: 59.0 rumz/s,
viscosity index: 158, pour poinl: -50°C, hereinafter, referred to as "ester
(A-2y).
20 [0052] [Example 3: Production of ester (A-3)]
Trimethylolpropane, 1,4-butanediol and &pic acid were reacted
in tfiethylolpropane/1,4-butanediolladipic acid = 110.212.4 (molar
ratio) to obtain an ester intermediate. n-Heptanol was M e r reacted
with this ester intermediate using neither a catalyst nor a solvent so that
25 the ratio of trimethylolpropaneln-heptanol was 1/1.6 (molar ratio), and
the remaining alcohol was removed by distillation. Then, an
adsorption treatment (clay treatment) was performed in the final step to
remove traces of impurities, obtaining an ester (kinematic viscosity at
40°C: 75.8 m d i s , viscosity index: 148, hereinafter, referred to as "ester
(A-3)").
5 [0053] [Example 4: Production of ester (A-4)]
I Trimethylolpropane and adipic acid were reacted in
trimethylolpropaneIadipic acid = 112.4 (molar ratio) to obtain an ester
intermediate. 2-Cthylhexanol was further reacted with this ester
intermediate so that the ratio of trimethylolpropanel2-ethylhexanoI was
10 1/1.9 (molar ratio), and the remaining alcohol was removed by
distillaiion. Then, an adsorption treatment (clay treatment) was
performed in the final step to remove traces of impurities, obtaining an
ester (kinematic viscosity at 40°C: 68.8 d s , viscosity index: 120,
hereinafter, referred to as "ester (A-4)").
15 100541 [Example 5: Production of ester (A-511
Neopentyl glycol and adipic acid were reacted in neopentyl
glycolladipic acid = 1/03 (molar ratio) to obtain an ester intermediate.
3,5,5-Trimethylhexanoic acid was further reacted with this ester
intemediatc so that the ratio of neopentyl glycol1
3,5,5-trimethylhexanoic acid was 110.5 (molar ratio), and the remaining
fatty acid was removed by distillation. Then, an adsorption treatment
(clay treatment) was performed in ihe final step to remove traces of
impurities, obtaining an ster (kinematic viscosity: 71.5 m2/s,
viscosity index: 114, hereinafter, referred to as "ester (A-5)").
[0055] [Example 6: Production of ester (A-6)]
Neopentyl glycol, l,4-butanediol and adipic acid were reacted in
!.' t. ,
neopentyl glycoll1,4-butanediol/adipic acid = 110.111.2 (molar ratio) to !.. ..
obtain an ester intermediate. 3,5,5-Trimethylhexanol was further
reacted with this ester intermediate in neopentyl glycol1
3,5,5-trimethylbexano1= U0.3 (molar ratio) using neither a catalyst nor
5 a solvent, and the remaining alcohol was removed by distillation.
Then, an adsorption treatment (clay treatment) was performed in the
find step to remove traces of impurities, obtaining an ester (kinematic
viscosity at 40°C: 275.9 d s , viscosity index: 117, pour point: -35OC,
hereinafter, referred to as ester (A-6)).
10 [0056] [Example 7: Production of ester (A-7)]
Neopentyl glycol, 1,4-butanediol and adipic acid were reacted in
neopentyl glycol/l,4-butanedioUadipic acid = 1/0.4/3.1 (molar ratio) to
obtain an ester intermediate. 3,5,~-TrimethyIhexanol was further
reacted with &is ester intermedih in neopentyl glycol/
15 3,5,5-trirnethylhexanol= 1/35 (molar ratio) using neither a catalyst nor
a solvent, and the remaining alcohol was removed by distillation.
Then, an adsorption treatment (clay treatment) was performed in the
fmal step to remove traces of impurities, obtaining an ester (kinematic
viscosity at 40°C: 32.2 m2/s, viscosity index: 161, pour point: -55"C,
20 hereinafter, referred to as ester (A-7)).
[0057] [Example 8: Production of ester (A41
Neopentyl glycol and adipic acid were xeacted in neopentyl
glycolladipic acid = 110.8 (molar ratio) to obtain an ester intermediate.
3,5,5-Trimethylhexanoic acid was reacted with this ester intermediate in
25 neopentyl glycoU3,5,5-trimethylhexanoic acid = 110.3 (molar ratio)
using neither a catalyst nor a solvent, and the remaining alcohol was
, i
i
removed by distillation. Then, an adsorption treatment (clay .1 .
treatment) was performed in the final step to remove traces of
i
impurities, obtaining an ester (kinematic viscosity at 40°C: 300 mm2/s, I
viscosity index: 114, pour poinl: -35OC, hereinafter, referred to as ester i
5 (A-8)).
[0058] The kinematic viscosity and the viscosity index of each of esters
(A-1) to (A-8) were measured or calculated according to JIS K2283.
In addiion, ihe porn- point was measured according to .JlS K 2269-1987.
[0059] [Examples 9 to 67 and Comparative Examples 1 to 45:
10 Production and evaluation of refrigerating macbine oil]
In each of Examples 9 to 67, each of esters (A-1) to (A-8) above
was used as the base oil, and 0.1% by mass of di-tea-butyl-p-cresol
@BPC) (based on the total amount of each reiiigerathg machine oil) as
the antioxidant was blended therewith to prepare each refigmating
15 machine oil.
In Comparative Examples 1 to 45, each of (b-1) to (b-3), (c-1),
and (c-2) shown below was used as the base oil, and 0.1% by mass of
di-tert-.butyl-p-cresol (DBPC) (based on the total amount of each
refrigerating machine oil) as the antioxidant was blended therewith to
20 prepare each refrigerating machine oil.
The type of each of the base oils used in Examples 9 to '67 and
Comparative Examples 1 to 45 is shown in Tables 1 to 16.

I (b-1) ester of pentaerythritol with a mixed acid of 2-mnethylpropanoic
i 25 acid and 3,5,5-trimethylhexanoic acid in a mass ratio of 1 : I (kinematic I
I viscosity at 40": 69.4 d s , viscosity index: 95, pour point: -45'C)
i
(b-2) ester of dipentaerythitol with a mixed acid of n-butanoic acid and 1
3,5,5-trimethylhexanoic acid in a mass ratio of 7 : 3 (kinematic viscosity
at 40°C: 68.1 &IS, viscosity index: 90)
(6-3) ester of trimethylolpropane with oleic acid (kinematic viscosity at
40°C: 50.3 m2/s, viscosity index: 176)
(b-4) ester of pentaerytbritol with pentanoic acid and
3,5,5-trimethylhexanoic acid (kinematic viscosity at 40°C: 31.4 d s ,
viscosity index: 118, pour point: less than -55°C)
(c-1) poly-a-olefin (PAO) (kinematic viscosity at 40°C: 34.0 rnm2/s,
viscosity index: 170, pour point: less than -55°C)
(c-2) poly-a-olefin (PAO) (kinematic viscosity at 40°C: 68.0 d s ,
viscosity index: 94, pour point: less than -55°C)
The kinematic viscosity and the viscosity index of each of base
oils @-I) to (b-4), (el) and (c-2) were measured and calculated
according to JIS K2283. In addition, with respect to each of (b-1) to
(b-4) among these base oils, an adsorption treatment (clay treatment)
was performed in the final step of production to remove traces of
impurities.
[0060] Then, each of the refrigerating machine oils in Examples 9 to 67
20 and Comparative Examples 1 to 45 was used to perform the following
tests.
[006 11 (Lubricity test)
A high pressure atmosphere friction tester (rotating-sliding
system of rotating vane material and fixed disk material), in which a
25 refrigerant atmosphere similar to the actual compressor could be made,
manufactured by Shinko Engineering Go., Ltd., was used to perform a
. . :
i :
lubricity test.' The test condition was any of the following lubricity
tests-(1) to (4) depending on the type of the refrigerant.
i
Lubricity test-(1): R32 was used as the refrigerant, and the pressure in I
the test vessel was 3.1 MPa.
5 Lubricity test-(2): HFO-1234yf was used as the refrigerant, and the
pressure inthe test vessel was 1.6 MPa.
Lubricity test-(3): R410A (in a mass ratio of R32/R125 = 111) was used
as the refrigerant, ai~dth e pressure in the test vessel was 3.1 MPa.
! Lubricity test-(4): n-hexane (n-C6) was blended in a volume of 20% to
10 that of the oil for the test (a hydrocarbon refrigerant such as R290 was
not sufficient in terms of safety, and was used as an alternative). The
pressure was only slightly higher than normal pressure.
Lubricity test-(5): R404A (in a mass ratio of MFG-125/HFC-l34a/
HFC-143a 44/4/52) was used as the refrigerant, and the pressure in
15 the lest vessel was 1.6 MPa
Lubricity test-(6): R407C (in a mass ratio of WFC-32/EIFC-1251
NFC-134a = 23/25/52) was used as the refrigerant, and the pressure in
the test vessel was 1.6 MPa
Lubricity test-(7): R134a was used as the refrigerant, and the pressure in
20 the test vessel was 1.6 m a .
Lubricity test-@): COa was used as the refrigerant, and the pressure in
the test vcssel was 1.6 NLPa.
The test conditions other than the above were as follows: the
mount of the ooil: 600 ml, the test temperature: llO°C, the number of
25 rotation: 500 rpm, the load applied: 80 kgf, and the test time: 1 hour,
which were common to those of all lubricity tests-(1) to (8). In
addition, SKH-51 was used as the vane material and FC250 was used as
the disk material, which were also common to those of all lubricity
tests-(1) to (8).
Herein, the evaluation of antiwear property was performed by
5 the wear depth of the vane material because the amount of wear of the
disk material was extremely small. The results obtained are shown in :
Tables 1 to 16.
[0062] (Stability test)
90 g of a reiXgerating machine oil whose moisture content was
adjusted to 100 ppm was weighed in an autoclave, and catalysts (wires
of iron, copper, and aluminum, each diameter: 1.6 mm x 50 mm) and 10
g of any of the following refrigerants:
Examples 9 to 16 and Comparative Examples 1 to 6: R32,
Examples 17 to 24 and Comparative Examples 7 to 12: HFO-1234yf,
15 Examples 25 to 30 and Comparative Examples 13 to 16: R410A,
Examples 3 1 to 35 and Comparative Examples 17 to 21: n-hexane,
Examples 36 to 43 and Comparative Examples 22 to 27: R404A,
Examples 44 to 51 and Comparative Examples 28 to 33: R407C,
Examples 52 to 59 and Comparative Examples 34 to 39: R134a,
Examples 60 to 67 and Comparative Examples 40 to 45: COZ
were included, and then heated to 17S°C, and observation of the
appearance and measurement of the acid value of a sample oil after 100
hours were performed. The results obtained are shown in Tables 1 to
16.
Herein, the acid value of each of the sample oils (new oils)
before the stability test was 0.01 mgKOWg.
[0063] [Table 11
I I E m ~ l9e 1 Example 10 I Example f 1 1 Exarnplc 12 I
[Table I] .(continued)
[Evaluation refrigerant]
-=Xe£rigerating mach'111e oil>
Type of base oil
Lubricity test
J.ubricity condition
Wear depthof vane @m)
Thermal stabiiq test
Appearance
Acid value (mgKOWg)
+
K32
A-1
(1)
7.2
No precipitate
0.01
K32
A-2
(1)
8.4
No precipitate
0.01
R32
A-3
(1)
8.3
No precipitate
0.0 1
R32
A-4
(1)
11.2
No preoipitate
0.01
LO0641 [Table 21
[O065] [Table 33
Acid value (mgK0Wd
Comp.
Example 6
R32
c-2
[Evaluation refrigamtl
aeeigerating machine oil>
Type of base oil
0.01
Comp.
Example 2
R32
b-2
Comp.
Example 1
R32
b-1
Lubricity test
Lubricity condition
Wear depth of vane (lun)
Thermal stability test
0.01
p a r a n - I precipitate /precipitate 1 ( precipitate ( precipitate 1 precipitate
(1)
16.2
No
Comp.
Example 3
R32
b-3
(1)
---1-4.1 -
No
0.08
Comp.
Example 4
R32
b-4
(1) (1)
16.7 16.1
Comp.
Example 5
R.32
c-1
No
0.11
No
0.01 0.01
No No
[Table 31 (continued)
( Example 21 Example 22 1 Example 23 / Example 24

Type of base oil
Lubricity test
Lubricity condition
Wear depth of vane (pm)
Thermal stabiity test
Appearance
[0066] [Table 41
Acid value (mgKOWg)
-
I I cow. I comp. comp. c o q . Camp. Comp.
A-5
(2)
7.9
No preoipirate
Lubricity condition
Thermal stability test
[Evaluation refrige~antl
0.17
HFO- 1234yf HFO- 1234yf
A-6
(2)
6.3
No precipitate
0.04
Acid value (mgKOWg)
HFO- 1234yi
A-7
(2)
7.4
No precipitate
HFO- 1234yf
A-8
(2)
6.2
No precipitate
0.03
0.03
0.05
0.05 0.07 0.18 1 0.06 1 0.07
[0067] [Table 51
I Example I Example / Example I Example / E ~ ~ ~ ~ I ~ T F X Z ]
b~e~i~eracmiancghi ne oil> / I 1 I 1 I I
25
il"; ofbaseoil 1 A-: Lubricity test 1 *:
Lubricity condition
Thelma1 stability tesl
26
No No No No No No
Appearance
precipitate precipitate precipitate precipitate precipitate precipitate
Acid value (mgKWg) 0.01 0.01 0.08 0.02 0.01 0.02 -
[0068] [Table 61
Lubricity condition
27
[Evaluation re%gerantlt] R410A
28
R410A R410A
29
R410A R410A
30
R410A
[00701 [Table 81
,
i
I
[0069] [Table 71
Comp. Comp.
No No No No No
Appearance
precipitate precipitate precipitate precipitate precipitate
0.01 0.03 0.08 0.01 0.01
5
i
!
ig
. ,
Example 35
n-C6
A-8
(4)
7.5
No
precipitate
0.02
.[..E. valuation refrigerant]
aefrigerating machine oil>
%e of base oil
~-
Lubricity test
Lubricity condition
Wear depth of vane (pm)
Thermal stability test
Appwance
Acid value (mgKOWg)
Example 32
a-C6
A-4
(4)
12.3
No
precipitate
0.01
Example 31
n-C6
A-3
(4)
9.1
No
precipitate
0.01
Example 33
n-C6
A-6
(4)
7.7
No
precipitate
0.02
Example 34
n-C6
A-7
(4)
8.2
~
No
precipitate
0.01
[0071] [Table 91

(Ty~oef base oil 1 A-1 [ A-2
kubriciv test I
Lubricity condition
Wear depth af vane (p)
Appearance No precipitate
Acid value (mgKOHlg)
El-ple 38 1 Example 39 I
[Table 91 (continued)
ITVpe of base oil I A-5 I Ad ( A-7 / A-8 1
Example 40
K404A

\Lubricity test I
/Lubricity condition I
Example 41
R404A
Thermal stability test
bppearance / NO precipitate
Example 42
R404A
Acid value (mgKOWg) 0.06
Example 43
R404A
No precipitate No precipitate No pl-ecipitate
0.01 0.01 0.01
FP13-03813-00
j
i
I
I i
[0072] [Table 101 I
i
. .
1 Appearance , ~ N o ~ N o ~ N o ~ N o ~ I i o precipitate precipibte precipitate precipitate precipitate precipitate ~ Acid value (mgKOII/g) 0.01 0.01 0.03 0.10 0.01 0.01
6.0 6.0
No precipitate No precipitate NO precipitate
0.01 0.01
lo0731 [Table 111
[Evaluation refrigerant]
Gefrigerating machine oil>
Type of base oiJ
Lubricity test
Lubricity condition
Wear depth ofvane (&m)
Thermal stability test
Appearance
Acid value (rngK0IVg)
Example 44
R407C
A- 1
(6)
5.7
No precipitate
0.01
[Table 1 I] (continued)
[0074] [Table 121
Appearance / No I No 1 No 1 No 1 No 1 No 1
precipitate precipitate precipitate precipitate precipitate predpitae
Acid LAcLid v-alu e (mgKOWg) 0.01
0.01 0.01 0.011 0.01 0.01
Lubricity tea
Lubricity condition
~ValuationteiXgetant]

Lubricity test
l~ubrioityc ondition 1 (7)
Wear depth of vane (pm)
Thermal stability test
Appearance
precipitate
Acid value (mgKOH/g) 0.01
! I
: i
Comp. Comp. Comp. Comp. Comp. I
Example 35 Example 36 Example 37 Example 38 Exampis 39 .. I..
precipitate I
No
precipitate
0.02
No
precipitate
0.11
100771 Fable 151
1~ubrioicto~n dition / (8) 1 (8) , 1 (8) 1 (8)
Type of bace oil
l~ppearance 1 No precipitate No precipitate I No precipitate 1 No precipitat
Example 62
Co1
Example 61
[Evaluation cefiigeraat] C02
%frige~ating machine oil1
Lubricity test
A-1
Wear depth of vane (w)
Example 63
cO2
Example 60
C02
A-2
Themat stabiity test
6.0
Acid value (mgKOWg) 0.01
6.5
A-3
5
0.01
A-4
0.01
Lubricity condition
[Table 151 (continued)
reardepihofvane(pm) I 6.3 1 5.6 1 6.1 1 5.3 1
Tl~ennaslt ablibnity test
( ~ ~ ~ e a r a n c e 1 No preoipitate I No precipitate I No precipitate
[Evaluation refrigerant]
%frigerating machine oil>
Example 66
co2
[0078] [Table 161
Examp-le -67. --
coz
Example 64
col
Acid value (mgKOH/g)
Comp. c q .
Example 65
co2
5
[0079] The evaluation results were shown in Tables 1,2 when R32 was
0.09
used, the evaluation results were shown in Tables 3, 4 when
IIFO-1234yf was used, the evaluation results were shown in Tables 5,6
0.01 0.01 0.01
when R410A was used, the evaluation results were shown in Tables 7,8
when n-hexane was used, the evaluation results were shown in Tables 9, I
I
10 when R404A was used, the evaluation results were shown in Tables
11, 12 when R407C was used, the evaluation results were shown in
Tables 13, 14 when R134a was used, and the evaluation results were
shown in Tables 15,16 when COz was used, respectively.
It can be seen that the refrigerating machine oil of each of
Examples 9 to 59 was favorable in antiwear property and also good in
skbility.
Xndustrial ApplicabiliQ
[0080] The lubricating base oil and the refrigerating machine oil of the
present invention are each a refrigerating machine oil that is excellent in
antiwear property and stability even under severe lubricating conditions,
and thus can be suitably used in a high-cooling efficiency refrigeration
system having a compressor, a condenser, a throttle device, an
evaporator, and the like among which the refigeraat is circulated, in
particular, in a system having a compressor such as a rotary-type,
swing-type, or scrolling-type, and can be used in the fields of a room
air-conditioner, an all-in-one air conditioner, a coolerator, a car
air-condi~oner,a n industrial refrigerator, and the like.
GLAlMS
1. A lubricating base oil comprising an ester synthesized from:
a first component that is at least one selected from polyhydric alcohols
having 2 to 4 hydroxyl groups;
5 a second component that is at least one selected &om polybasic acids
having 6 to 12 carbon atoms; and
a third component that is at least one selected from monohydric alcohols
having 4 to 18 carbon atoms and monocarboxylic acids having 2 to 12
carbon atoms.
10 2. The lubricating base oil according to claim 1, wherein the first
component comprises at least one selected horn neopentyl glycol,
trimethylolpropane and pentaeeitol.
3. The lubricating base oil according to claim 1 or 2, wherein the
first component comprises:
15 a first alcohol that is at least one selected fiom neopentyl glycol,
trimethylolpropane and pentaewtol; and
a second alcohol that is at least one selected from dihydric alcohols
having 2 to 10 carbon atoms other than neopentyl glycol.
4. The lubricating base oil according to any one of claims 1 to 3,
20 wherein the first component comprises at least one selected from
neopentyl glycol and trimethylolpropane.
5. The lubricating base oil according to any one of claims 1 to 4,
wherein the second component comprises at least one selected from
adipic acid and sebacic acid.
25 6. The lubricating base oil according to any one of claims I to 5,
wherein the first component comprises butanediol.
i
: !
:. 1
.' i 7. The lubricating base oil according to any one of claims 1 to 6,
wherein the third component comprises at least. one selected from
monobydric alcohols having 8 to 10 carbon atoms.
. .
8. A refrigerating machine oii containing the lubricating base oil j
according to any one of claims 1 to 7.
9. The refrigerating machiie oil according to claim 8, being used
with a refrigerant comprising at least one selected from
hydrofluorocarbons, hydrofluorooleiins, hydrocarbons having 2 to 4
carbon atoms, and carbon dioxide.
10. The refrigerating machine oil according to claim 8 or 9, being
used with a refrigerant having a global wariui~~pgo tential of 1000 or
less.
11. The refrigerating machine oil according to any one of claims 8
to 10, being used wifh a refitgerant having a global w a r h g potential
of 700 or less.
12. The refrigerating machine oil according to any one of claims 8
.to 11, being used with a refrigerant comprising difluoromethane.
13. The refrigerating machine oil according to any one of claims 8
to 12, being used with a refrigerant comprising propane or isobutane.
14. The refrigerating machine oil according to any one of claims 8
to 12, being used with a refrigerant comprising at least one
hydrofluoropropene.
15. A working fluid composition for a refrigerating machine,
comprising:
a refrigerating machiie oil comprising the lubricating base oil according
to my one of claims 1 to 7; and
:.. ,.
j
I, :
a refrigerant conlprising at least one selected fi-o.orahydrofluo~.ocarbons,
. .
,I
hydrofluoroolefins, hydrocarbons having 2 to 4 carbon atoms, and
,, . : carbon dioxide.