Tecli~iicaFl ield
[0001] The present invention relates to a refrigerating machine oil, a
working fluid con~position for a refrigerating machine, use of a
composition containing a polymer as a base oil for a refrigerating
machine oil or a working fluid composition for a refrigerating machine
10 and use of a polymer for manufacturing a refrigerating machine oil or a
working fluid composition for a refrigerating machine.
Background Art
[0002] Recently, destruction of the ozone layer has been concerned.
Due to this problem, CFC (chlorofluorocarbons) and HCFC
15 (hydrochlorofluorocarbons) conventionally used as refrigerants for
refrigerating machines become subjects to regulation and alternatively
XlFC (hydrofluorocarbons) has been increasingly used as a refi-igerant.
In addition, refrigerants having a lower global warming potential
(GWP) than WC refrigerants have been developed (for example, see
20 Patent Literature 1).
[0003] In the meantime, in the cases of using conventional CFC and
HCFC as refrigerants, a refrigerating machine oil such as a mineral oil
and a hydrocarbon oil including alkyl benzene have been suitably used.
Since behaviors of a refkigerating machine oil such as compatibility
25 with a refrigerant, lubricity, dissolution viscosity to the refi-igerant and
tl1ema1/chemical stability vary depending upon the type of refrigerant
used in coinbination and cannot be expected, a rekigerating machine oil
inust be developed for every refrigerant.
Citation List
Patent Literature
5 [0004]Patent Literature 1: International Publication No.
WO2005/105947
Summary of Invention
Techl~icaPl roblem
[0005] An object of the present invention is to provide a rekigerating
10 machine oil excellent in suitability with a predete~~nineredf ~igeranat nd
a working fluid colnposition for a refrigerating machine using the
refrigerating machine oil.
Solution to Probleni
[OOOG] The present invention provides a rekigerating machine oil
15 comprising, as a base oil, a polymer having a structural unit represented
by the followiug formula (1):
wherein R', and R3, which may be the same as or different from each
other, represent a hydrogen atom or a hydrocarbon group; and R4
20 represents a hydrocarbon group or an organic group containing an
oxygen atom, and having a nwnber average lnolecular weight Mn of
300 or more and 3000 or less and a ratio of a weight-average molecular
weight Mw to a number average molecular weight Mn (MwMn) of
1.10 or more and 2.00 or less, and the reftigerating machine oil being
used with a refrigerant selected fiom tile group consisting of
difluoromethane, a mixture of difluorotnethane and pentafluoroethane, a
5 mixture of difluoromethane, pentafluoroethane and
1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l,l-tsifluoroethane, unsaturated
hydrofluorocarbons, hydrocarbons and carbon dioxide.
[0007] The present invention also provides a working fluid composition
10 for a refrigerating machine comprising: a refrigerating machine oil
comprising, as a base oil, a polymer having a structusal unit represented
by the above formula (I), and having a number average molecular
weight Mn of 300 or more and 3000 or less and a ratio of a
weight-average molecular weight Mw to a number average molecular
15 weight Mn (Mw/Mn) of 1.10 or more and 2.00 or less; and a refrigerant
selected fkom the group consisting of difluoromnethane, a mixture of
difluoromethane and pentafluoroethane, a mixture of difluoromethane,
pentafluoroethane and 1,1,1,2-tetrafluoaoethane, a mixture of
pentafluoroethane, 1,1,1,2-tetrafluoroethane and 1, 1 ,1-trifluoroethane,
20 unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.
[0008] The present invention also relates to use of a composition
comprising a polymer as a base oil for a reEigerating machine oil or a
working fluid composition for a aefiigerating machine, wherein the
polymer has a structural unit reprcsented by the above fomula (I),
25 wherein the polymer has a nutnber average molecular weight i%l of 300
or more and 3000 or less and a ratio of a weight-average molecular
weight Mw to a number average molecular weight Mn (Mw/Ivln) of
1.10 or more and 2.00 or less, wherein the refiigerating machine oil is
used with a refiigerant selected fionl the group consisting of
difluoromethane, a mixture of difluoromethane and pentafluoroethane, a
5 mixture of difluoromethane, pentafluoroethane and
1,l ,I ,2-tetrafluoroethane, a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l, 1-tritluoroethane, utlsaturated
bydrofluorocarbons, hydrocarbons and carbon dioxide, and wherein the
working fluid composition for a refiigerating machine comprises a
10 refrigerating machine oil and a refrigerant selected from the group
consisting of difluoromethane, a mixture of difluoromethane and
pentafluoroethane, a mixture of difluoromethane, pentafluoroethane and
1 ,I, 1,2-tetrafluoroethane, a mixhire of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l ,l-trifluoroethane, unsaturated
1 S hydrofluorocarbons, hydrocarbons and carbon dioxide.
[0009] 171e present invention also provides use of a polymer for
manufacturing a refrigerating machine oil or a working fluid
composition for a refrigerating machine, wherein the polymer has a
structural unit represented by the above formula (I), wherein the
20 polymer has a number average moleculas weight Mn of 300 or more
and 3000 or less and a ratio of a weight-average molecular weight Mw
to a number average molecular weight Mn (MwIMn) of 1.10 or more
and 2.00 or less, wherein the refrigerating machine oil is used with a
refrigerant selected from the group consisting of difluoromethane, a
25 mixture of difluoromethane and pentafluoroethane, a mixture of
difluoromethane, pentafluoroethane and 1,1,1,2-tetrafluoroethane, a
mixture of pentafluoroethane, 1 ,I, 1,2-tetrafluoroethane and
1,l ,l -tsifluoroethane, unsaturated hydrofluorocarbons, l~ydrocarbons
and carbon dioxide, and wherein the working fluid composition for a
refrigerating machine comprises a refrigerating machine oil and a
5 refrigerant selected from the gsoup consisting of difluoron~ethane, a
mixture of difluoroinethane and pentafluoroethane, a mixture of
difluoromethane, pentafluoroethane and 1 ,I, 1,2-tetrafluoroethane, a
mixture of pentafluoroethane, 1,1,1,2-tetrafluoroethane and
1,l , 1-trifluoroethane, unsaturated hydrofluorocarbons, hydrocarbons
10 and carbon dioxide.
Advantageous Effects of Invention
[0010] According to the present invention, it is possible to provide a
refrigerating machine oil excellent in suitability with a predetermined
refrigerant and a working fluid composition for a refi-igerating machine
15 using the refrigerating machine oil.
Description of Embodiments
[0011] The refiigerating machine oil according to the embodiment
contains, as a base oil, a polymer (hereinafter also referred to as
"(1neth)acrylate polymer"), which has a structural unit represented by
20 the following formula (1):
wherein R', R' and R ~w,h ich may be the same as or different from each
othel; represent a hydrogen atom or a l~ydrocarbon group; and R~
represents a hydrocarbon group or an organic group containing an
oxygen atom, which has a number average nlolecular weight Mn of 300
or more and 3000 or less and a ratio of a weight-average molecular
5 weight Mw to a number average lnolecular weight Mn, i.e., MwM, of
1.10 or Inore and 2.00 or less, and to be used with a refrigerant selected
from difluoromethane, a mixture of difluoromethane and
pentafluoroethane, a mixture of difluoromethane, pentafluoroethane and
1,1, I ,2-tetrafluoroethane, a mixture of pentafluoroethane,
10 1,1,1,2-tetrafluoroethane and l,l, 1-l~ifluoroethane, unsaturated
hydrofluorocarbons, hydrocarbons and carbon dioxide.
[0012] The working fluid composition for a refrigerating machine
according to the embodiment contains a refrigerating machine oil
containing, as a base oil, a polymer, which has a structural unit
15 represented by the above formula (I), a number average molecular
weight Mil of 300 or more and 3000 or less and a ratio of a
weight-average molecular weight Mw to a number average molecular
weight Mn, is., MwfluIn, of 1.10 or more and 2.00 or less; and a
rehigerant selected from difluoromethane, a mixture of difluoromethane
20 and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane
and I ,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
1 ,I ,I ,2-tetrafluoroethane and I ,l ,1 -trifluoroethane, unsaturated
hydrofluorocarbons, hydrocarbons and carbon dioxide. The working
fluid composition for a refrigerating machine according to the
25 cmbodimellt includes an aspect containing the refrigerating machine oil
according to the embodiment and a rehigerant selected horn
difluoromethane, a mixhire of difluoromethane and pentafluoroethane, a
mixture of difluoromnethane, peniafluoroethane and
1,1,1,2-tetrafluoroethane a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and 1,1,1 -trifluoroethane, unsaturated
5 hydrofluorocarbons, hydrocarbons and carbon dioxide.
[0013] In the formula (I), the number of carbon atoms of the
hydrocarbon gsoup represented by each of R', R2 and R~ is preferably 1
to 8, more preferably 1 to 5 and further preferably 1 to 3. In the
formula (I), it is preferable that R' and R3 are each a hydrogen atom and
10 R' is a hydrogen atom or a methyl group.
[0014] In the formula (I), R4 represents a hydrocarbon group or an
organic group containing an oxygen atom. The number of carbon
atoms of the hydrocarbon group represented by R4 is preferably 1 to 10,
more preferably 1 to 5 and further preferably 1 to 3. In all structural
15 units constituting a (meth)acrylate polymer, an average number of
carbon atoms of the hydrocarbon group represented by R~ is preferably
1 to 10, more preferably 1 to 5 and further preferably 1 to 3. Examples
of the organic group containing an oxygen atom include a linear or
branched hydrocarbon group containing an oxygen atom constituting an
20 ether bond and a hydrocarbon group having a glycidyl group.
[0015] It is preferable that -0R4 jn the formula (1) is represented by the
following formula (2):
-0(R50),R6 (2)
wherein R5 represents a divalent hydrocarbon group or a divalent
25 hydrocarbon group containing an ether-bond oxygen atom; R6
represents a hydrocarbon group; and m represents an integer of 0 or
more. Lf m is 2 or more, a plurality of R5 may be the same as 01
different fro111 each othes.
[0016] In the formula (2), the number of carbon atoms of the divalent
hydrocarbon group and hydrocarbon group containing an ether-bond
5 oxygen atom which are represented by R' is preferably 1 to 10, more
preferably 1 to 5 and fi~rtherp referably 1 to 3. In the fonnula (2), the
divalent hydrocarbon group containing an ether-bond oxygen atom
which is represented by R5 may be a hydrocarbon group having, for
example, an oxygen atom constituting an ether bond at a side chain.
10 [0017] In the formula (2), it is preferable that R6 is a hydrocarbon group
having 1 to 20 carbon atoms. Examples of the hydsocarbon .group
include an alkyl group, a cycloalkyl group, a phenyl group, an aryl
group and an arylalkyl group. Of these, an alkyl group is preferable
and an alkyl group having 1 to 5 carbon atoms is more preferable.
15 [0018] In the formula (2), m is an integer of preferably 0 or more, more
preferably 1 or more; and is also an integer of preferably 20 or less,
more preferably 10 or less and hsther preferably 5 or less. It is
preferable that the average value of m in all stsuctural units constituting
a (meth)aciylate polymer is 0 to 10.
20 [0019] The (meth)ac~ylatep olymer may be a homopolylner composed
of a single stsuctural unit selected fiom those represented by the fosmula
(I), a copolynler composed of two or more structural units selected fsom
those represented by the formula (I) or a copolymer composed of a
sttuctural unit represented by the formula (l).and another structural unit.
25 If the (meth)ac~ylate polymer is a copolymer, compatibility with a
refrigerant of a refsigerating machine oil is satisfied, at the same time,
properties thereof such as lubricity, insulation properties and
hygroscopicity can be further iniproved.
[0020] If the (meth)acrylate polymer is a copolymer, it is preferable that
the copolyim has at least one structural unit selected from the
5 stiuctural units represented by the above formula (1) wherein R~ is an
a w l group having 1 to 4 carbon atoms. This copolymer ]nay have
two or more str.uct11ra1 units selected from structural units represented
by the above formula (1) wherein R4 is an alkyl group having 1 to 4
carbon atoms; or may have one or more stluctural units selected from
10 the structural units represented by the above formula (1) wherein R4 is
an alkyl group having 1 to 4 carbon atoms and one or more structural
units selected from the structural units represented by the above formula
(1) wherein R4 is an allcyl group having 5 to 8 carbon atoms or an
organic group containing an oxygen atom. The content of the
15 structural units represented by the above fornlula (1) wherein R~ is an
alkyl group having 1 to 4 carbon atoms based on the total amount of the
stluctural units constituting the copolymer is preferably 50% by mole or
more, more preferably 70% by mole or more, Wher preferably 80% by
mole or more and particularly preferably 96% by mole or more.
20 [0021] Of the above copolymers, for example, the following
copolymers (A) to (E) are suitable. Note that, R' to R4 described in
(A) to (E) respectively refer to R' to R~ in the above formula (1).
(A) a copolymer having a structural unit wherein R' to R3 are
each a hydrogen at0111 and R~ is an ethyl group; a structural unit wherein
25 R1 to R3 are each a hydrogen atom and lc4 is a n-butyl group; and a
structural unit wherein R' to R3 each is a hydrogen atom and R4 is an
i-butyl group (2-n~ethylpropygl roup).
(B) a copolymer having a structural unit wherein R' to R3 are
each a hydrogen atom and R4 is an ethyl group; and a structural unit
wherein R' to R3 are each a hydrogen atom and R4 is a propyl group.
5 (C) a copolymer having a structusal unit wherein K' and R3 are
each a hydrogen atom and R2 and R4 al.e e ach a methyl group; and a
structural unit wherein R' to R3 are each a hydrogen atom and R4 is an
i-octyl group (for example, 2-ethylhexyl group).
@) a copolymer having a slructural unit wherein R1 to R~ are
10 each a hydrogen atom and R4 is an ethyl group; and a structural unit
wherein R' and R3 are each a hydrogen atom; R2 is a methyl group and
R4 is a glycidyl group.
(E) a copolymer having a structural unit wherein R' to R3 are
each a hydrogen atom and R~ is an i-butyl group (2-methylpropyl
15 group); and a structural unit wherein R' and It3 are each a hydrogen
atom, R2 is a methyl group and R4 is a methoxyethyl group.
[0022] A (meth)acrylate polymer is produced by a known method
described, for example, in International Publication No.W001/083619.
At this time, if the types of raw material monomers, the type of initiator,
20 the ratio of structural units in a copolymer and the like are appropriately
selected, the above rekigerating machine oil having desired properties
can be obtained. Accordingly, a rekigerating machine oil satisfying
requirements for properties such as lubricity and co~npatibility, which
vary depending upon e.g., the compressor model in a refrigerating
25 system or an air conditioniug system, the material of the lubrication
unit, refkigerating capacity and the type of refrigerant, can be obtained
as desired. The copolytner may be either a block copolymer or a
ra~idomc opolymer.
[0023] The number average tnolecular weight @In) of a (1neth)acrylate
polymer is preferably 300 or more, more preferably 400 or more, further
5 preferably 500 or more and particularly preferably 600 or more; and
also preferably 3000 or less, more preferably 2000 or less, further
preferably 1500 or less and particularly preferably 1000 or less. If the
number average molecular weight is 300 or more, lubricity (in
particular, antiwear propesty) in the presence of a predetermined
10 refrigerant improves. If the number average molecular weight is 3000
or less, compatibility with a predetermined refrigerant improves.
100241 In the (meth)acrylate polymer, the ratio of weight-average
molecular weight (Mw) to number average molecular weight (Mn), i.e.
Mw/Mn, is preferably 1.10 or more, more preferably 1.11 or more,
15 further preferably 1.12 or more and particularly preferably 1.13 or more;
and also preferably 2.00 or less, more preferably 1.90 or less, further
preferably 1.80 or less and pat-ticularly preferably 1.70 or less. If the
M w k is 1.10 or more, compatibility with a predetermined refiigerant
improves. If the MwIMn is 2.00 or less, poor lubrication of a
20 refrigerant compressor and inhibition of heat exchange in an evaporator
can be suppressed. The weight-average molecular weight (Mw) of a
(1neth)aciylate polymer is appropriately selected such that Mn and
M w k satisfy the above conditions.
100251 In the present invention, the weight-average molecular weight
25 (M\.v), number average inolecular weight (Mn) and the ratio of
weight-average molecular weight (Mw) to number average molecular
weight (Mn), i.e. Mw/Mu, refer to Mw, Mn and MwIMn (polystyrene
(standard sample) equivalent) obtained by GI'C analysis. Mw, Mn and
Mw/Mn can be measured, for example, as follows.
[0026] Using tetrahydrofuran as a solvent, a sample is diluted to
5 prepare a sample solutioil having a concentration of 1% by mass. 'I'fle
sample solution is subjected to analysis using a GPC apparatus (Waters
Alliance2695). Using a column (an analyzable molecular weight of
100 to 10000) at a solvent flow-rate of I rnllmin, analysis is cmied out
by a refractive index detector. Note that, using polystyxene whose
10 molecular weight is known as a standard, the relationship between the
columl retention time and the molecular weight is separately obtained
to prepare a calibration curve in advance. Based on the calibration
curve, the molecular weight is determined fiom the obtained retention
time.
15 [0027] The flash point of a (meth)acrylate polymer is preferably 195°C
or more, more preferably 200°C or more and mher preferably 205°C
or more. In the present invention, the flash point refers to a value
measured in accordance with JIS K2265-4: 2007, "how to obtain flash
point, part 4: Cleveland open cup".
20 [0028] The autoignition point of a (meth)acrylate polymer is preferably
335°C or more, more preferably 340°C or more and fuither preferably
345°C or more. In the present invention, the autoignition point refers
to a value measured in accordance with ASTM E659-1978.
COO291 The kinematic viscosity at 40°C of a (meth)aciylate polymer is
25 preferably 10 ~nm~olrs m ore, more preferably 20 mm2/s or more and
further preferably 30 m1112/s or more; and also preferably 400 mn2/s or
less, more preferably 300 nun2/s or less and further preferably 200
d s or less. If the kiuematic viscosity at 40°C is the lower limit or
more, lubricity and sealing of the colnpressor tend to iniprove. If the
lcinematic viscosity at 40°C is the upper limit or less, the range of a
5 composition exhibiting compatibility with a refrigerant in low
temperature conditions is widen, with the result that poor lubrication of
a refrigerant compressor and inhibition of heat exchange in an
evaporator can be suppressed.
[0030] The k'ienlatic viscosity at 100°C of a (meth)acrylate polymer is
10 preferably 1 nun21s or more, more preferably 2 mm2/s or more and
further preferably 3 d s or more; and also preferably 50 m d s or
less, more preferably 40 m d s or less and haher preferably 30 mn2/s
or less. If the kinematic viscosity at 100°C is the lower limit or more,
lubricity in the presence of a refiigerant improves. If the kinematic
15 viscosity at 100°C is the upper limit or less, the range of a composition
exhibiting compatibility with a refrigerant is widen, with the result that
poor lubrication of a refrigerant compressor and inhibition of heat
exchange in an evaporator can be suppressed.
[003 11 The viscosity index of a (meth)acrylate polymer is preferably 80
20 or more, more preferably 90 or more and h-ther preferably 100 or
more; and also preferably 200 or less, more preferably 180 or less and
further preferably 150 or less. If the viscosity index is the lower limit
or more, the lubricity (in particular, antiwear property) at high
temperature in the presence of a predetermined refrigerant improves.
25 If the viscosity index is the upper limit or less, the lubricity (in
particnlar, antiwear property) in the presence of a predetermined
refrigerant at low temperature improves.
[0032] In the present invention, kinematic viscosities at 40°C and
100°C and viscosity index refer to the values nleasured in accordance
with JIS I<-2283: 1993.
5 [0033] The pour point of a (meth)acrylate polymer is preferably -10°C
or less, more preferably -20°C or less and preferably -50°C or more. If
a (1neth)aclylate polymer having a pour point of -1 O°C or less is used,
solidification of the refrigerating machine oil in a refrigerant circulation
system tends to be suppressed at low temperature. Iu the present
10 invention, the pour point refers to the value measured in accordance
with JIS K2269: 1987.
[0034] A refiigerating machine oil may contain a (1neth)acrylate
polymer alone and may further contain a base oil other than the
(1neth)acrylate polymer and lor additives. In the refiigerating machine
15 oil, the content of a (meth)acrylate polymer is not particularly limited as
long as the aforementioned excellent properties are not impaired;
however, the content is preferably 50% by mass or more, more
preferably 70% by mass or more, further preferably 80% by mass or
more and particularly preferably 90% by mass or more based on the
20 total amount of the refrigerating machine oil. If the content of a
(meth)acrylate polymer is 50% by mass or more, suitability with a
predetermined refsigerant can be more improved.
[0035] As the base oil other than a (1neth)acrylate polymer, a mineral
oil; a hydrocarbon-based oil such as an olefin polymer, a naphthalene
25 conlpound and an alkylbenzene, an ester base oil (such as a monoester,
a diester, a polyol ester); and a synthetic oil (oxygen-containing oil)
constituted of a compound containing oxygen as a constituent element,
such as a polyalkylene glycol, a polyvinyl ether, a ketone, a polyphenyl
ether, a silicone, a polysiloxane and a perfluoro ethet; can be used. As
the oxygen containing oil, a polyol ester, a polyalkylene glycol and a
5 polyvinyl ether are preferal~lyu sed.
[0036] In order to obtain excellent propesties required for a
refrigerating machine oil such as lubsicity, compatibility,
ther~nal/chemical stability and electrical insulating property, the content
of a base oil based on the total amount of the refsigerating machine oil is
10 preferably 80% by mass or more, more preferably 90% by mass or more
and further preferably 95% by mass or more.
[0037] Examples of the additive include an acid scavenger, an
antioxidant, an extreme pressure agent, an oiliness agent, a defoaming
agent, a metal deactivator, an antiwear agent, a viscosity index
15 improver, a pour point depressant, a detergent-dispersant, a friction
modifier and a nlst inhibitor. The content of an additive(s) is
preferably 5% by mass or less and inore preferably 2% by mass or less,
based on the total amount of the refrigerating machine oil.
[0038] Of the aforementioned additives, an acid scavenger is preferably
20 further contained in the refrigerating machine oil in order to hither
improve the~malfcheraical stability, Examples of the acid scavenger
include an epoxy compound and a casbodiimide comnpound.
[0039] Examples of the epoxy compound include, but are not
pasticulasly limited to, a glycidyl ether epoxy compound, a glycidyl
25 ester epoxy compound, an oxirane compound, an alkyloxirane
compound, an alicyclic epoxy compound, an epoxidized fatty acid
non no ester and an epoxidized vegetable oil. These epoxy conlpounds
can be used alone or iu combination of two or more.
[0040] Examples of the glycidyl ether epoxy compouttd include
n-butylphenyl glycidyl ether, i-buitylphenyl glycidyl ether,
5 sec-butylphenyl glycidyl ether, te1-t-butylphenyl glycidyl ether,
pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl
glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether,
decylphenyl glycidyl ether, decylglycidyl ether, undecylglycidyl ether,
dodecylglycidyl ether, tridecylglycidyl ether, tetradecylglycidyl ether,
10 2-ethylhexylglycidyl ether, neopentyl glycol diglycidyl ether,
trimethylolpropane triglycidyl ether, pentaewhritol tetraglycidyl ether,
1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether,
polyallrylene glycol nlonoglycidyl ether and polyallcylene glycol
diglycidyl ether.
15 [0041] Examples of the glycidyl ester epoxy compound include
glycidyl benzoate, glycidyl neodecanoate, glycidyl-2,2-dimethyl
octanoate, glycidyl acrylate and glycidyl methacrylate.
[0042] The alicyclic epoxy conlpound is a compound having a partial
structure represented by the following formula (3):
wherein carbon atoms constituting an epoxy group directly constitute an
alicyclic ring.
[0043] Examples of the alicyclic epoxy compound iilclude
1,2-epoxycyclohexane, 1,2-epoxycyclopentane,
3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate,
bis(3,4-epoxycyclohexylmethyl) adipate, exo-2,3-epoxynorbornane,
bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate,
2-(7-oxabicyclo[4.1 .O]hept-3-yl)-spiro(1,3-dioxane-5,3'-[7]oxabicyclo[4
5 .l.O]heptane, 4-(1'-methylepoxyethyl)-I,2-epoxy-2-methylcyclohexane
and 4-epoxyethyl-l,2-epoxycyclohexane.
[0044] Examples of the ally1 oxirane compound include 1,2-epoxy
styrene and alkyl-1,2-epoxy styrene.
[0045]Examnples of the alkyl oxirane compound include
10 1 &epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane,
1,2-epoxyheptane, 1,2-epoxyoctane, 1,2-epoxynonane,
1,2-epoxydecane, 1,2-epoxyundecanc, 1,2-epoxydodecane,
1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane,
1,2-epoxyhexadecane, 1,2-epoxyheptadecane, 1,1,2-epoxyoctadecane,
15 2-epoxynonadecane and 1,2-epoxyeicosane.
[0046] Examples of the epoxidized fatty acid monoester iuclude an
ester of an epoxidized fatty acid having 12 to 20 carbon atoms and an
alcohol having 1 to 8 carbon atoms, phenol or an alkylphenol. As the
epoxidized fatty acid monoester, butyl, hexyl, benzyl, cyclohexyl,
20 mcthoxyetllyl, octyl, phenyl and butylphcnyl esters of epoxystearate are
preferably used.
[0047] Examples of the epoxidized vegetable oil include epoxy
compounds of vegetable oils such as soybean oil, linseed oil and
cottonseed oil.
25 [0048] As the carbodiimide coinpound, which is not pa~ticularly
limited, dialkylcarbodiimide, diphenyl carbodiimide and
bis(alkylplleny1) carbodiimide can be used. Exatnples of the
dialkylcarbodiimide include diisopropylcarbodii~nide and
dicyclohexylcarbodiirnide. Examples of the bis(alkylpheny1)
carbodiimide include ditolylcarbodii~nide,
5 bis(isopropylpheny1)cal-bodiitnide, bis(diisopropylphenyl)carbodiimide,
bis(triisopropylphenyl)carbodiiinide, bis(b~itylphenyl)carbodiirnide,
bis(dibutylpheny1)carbodiimide and bis(nonylpheny1)carbodiimide.
[0049] Of the additives, a wear inhibitor is preferably further contained
in a refrigerating machine oil. Preferable exa~nples of the wear
10 inhibitor include phosphorates, thiophosphates, sulfide compounds and
zinc dialkyldithiophosphates. Of the phosphates, triphenyl phosphate
(TPP) and tricresyl phosphate (TCP) are preferable. Of the
thiophosphates, triphenylphosphorothionate ( P ) is preferable.
Examples of the sulfide compounds include many compounds;
15 however, a monosulfide compound is preferable since it can ensure the
stability of a refi-igerating machine oil and can suppress deterioration of
copper used in a refrigerating machine.
[0050] Of the above additives, an antioxidant is preferably further
contained in a reftigerating machine oil. Examples of the antioxidant
20 include phenolic compounds such as di-te1-t-butyl-p-cresol and arnine
compounds .such as alkyl diphenylamine. In pal-ticular, a phenolic
compound is preferably contained as an antioxidant in a refrigerating
machine oil in an amount of 0.02% by mass or more and 0.5% by mass
or less, based on the total amount of the refrigerating machine oil.
25 LO05 11 Of the above additives, a friction modifier, an extreme pressure
agent, a rust inhibitor, a metal deactivator and a defoaming agent are
preferably furtl~erc ontained in a refrigcrating machine oil. Exail~ples
of the fi-iction modifier include an alipl~atica mine, an aliphatic amidc,
an aliphatic imide, an alcohol, an ester, a phosphate amine salt and a
phosphite amine salt. Examples of the extreme pressure agent include
5 a sulfilrized olefiui and a sulfurized fat and oil. Examples of the rust
inhibitor include an ester or partial ester of an alkenyl succinic acid.
Examples of the metal deactivator include benzotriazole and a
benzotriazole derivative. Examples of the defoa~ninga gent include a
silicone compound and a polyester compound.
10 [0052] The kinematic viscosity at 40°C of a reiiigerating machine oil,
which is not particularly limited, is preferably 3 min2/s or more, more
preferably 4 mm2/s or more and fbrther preferably 5 mnm2/s or more; and
also preferably 1000 nim2/s or less, more preferably 500 mm2/s or less
and further preferably 400 rmn2/s or less. The kinematic viscosity at
15 100°C of a refrigerating machine oil, which is not particularly limited, is
preferably 1 mm2/s or more, more preferably 2 mm2/s or more and
furfher preferably 3 mm2/s or more; and also preferably 100 m2/s. or
less, more preferably 50 mm2/s or less and hither preferably 30 rnrp2/s
or less.
20 [0053] The moisture content of a reEigerating machine oil, which is not
particularly limited, is preferably 500 ppm or less based on the total
amount of the refrigerating machine oil, more preferably 300 ppm or
less and further preferably 200 ppm or less. If a refrigerating machine
oil is used pa~ticuIarly in a closed-type refrigerating machine, in
25 consideration of the the~mallche~nicaslt ability of a reeigerating
machine oil and the effect on electrical insulating properties, the
moisture content is preferably low.
[0054] The acid value of a refrigerating machine oil, which is not
paiticularly limited, is preferably 1.0 mgKOHIg or less and more
preferably 0.1 mgKOWg or less, in order to prevent coi~osion of the
5 metal used in a refkigerating machine or piping and prevent
decomposition of esters contained in the refiigerating machine oil of the
embodinlent. In the present invention, the acid value refers to a value
measured in accordance with JIS K2501: 2003, "Petroleuin products
and lubricants-neutralization value test nlethod".
10 [0055] The ash content of a refrigerating machine oil, which is not
particularly limited, is preferably 100 ppm or less and more preferably
50 ppm or less in order to enhance the thei?nal/chemical stability of a
rei?igerating machine oil and suppress generation of e.g., sludge. In
the present invention, the ash content refers to a value measured in
15 accordance with JIS K2272: 1998, "Ciude oil and petroleum
products-ash and sulfuric ash test method".
[0056] A composition containing a (meth)ac~ylate polymer and a
composition containing a (meth)acrylate polymer and the
aforementioned additives are suitably used as a constitutional
20 component of a refrigerating machine oil, which is to be used with a
refrigerant selected from difluoromethane, a inixture of difluoromethane
and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane
and 1,1,1,2-tetrafluoroethane, a mixtuse of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l, 1-trifluoroethane, an unsaturated
25 l~ydrofluorocarbon, a hydrocarbon and carbon dioxide, or as a
constitutional component of a working fluid composition for a
refiigerating machine containing the refiigerating machine oil and a
refi-igerant selected from difluoromethane, a mixture of difluoromethane
and pentafluoroethane, a mixture of ditluoromethane, pentafluoroethane
and 1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
5 1,1,1,2-tetrafluoroethane and 1,1,1-trifluoroethane, an unsaturated
hydrofluorocarbon, a hydrocarbon and carbon dioxide.
[0057] A (meth)acrylate polymer and the aforenlentioned additives are
suitably used for producing a refiigerating machine oil to be used with a
refiigeraut selected horn difluorometl~anea, mixture of difluoromethane
10 and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane
and 1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l ,l-trifluoroethane, an unsaturated
hydrofluorocarbon, a hydsocasbon and carbon dioxide, or a working
fluid composition for a rehigerating machine containing the
15 refrigerating machine oil and a refrigerant selected kom
difluoromethane, a mixture of difluoromethane and pentafluoroethane, a
mixture of difluoromethane, pentafluoroethane and
1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and l,l, I-trifluoroethane, an unsatusated
20 hydrofluorocarbon, a hydrocarbon and carbon dioxide.
[0058] The refrigerant to be used with a refrigerating machine oil and
the refrigerant contained in a working fluid composition for a
reeigerating machine are selected honl difluoromethane (R32), a
mixture of difluoromethane (R32) and pentafluoroethane (R125), a
25 mixture of difluoromethane (R32), pentafluoroethane (Xt125),
1,1,1,2-tetrafluoroethane @134a), a mixture of pentafluoroethane
(R125), 1,1,1,2-tetsafluoroethane (R134a) and l,l,l-trifluoroethane
(R143a), an unsaturated fluorinated hydrocarbon, a hydrocarbon and
carbon dioxide. The refiigerant may be one or two or more selected
from the above. 'I'llc content of the refrigerant selected from the above
5 is preferably 60 to 100% by mass based on the lotal amount of the
refrigerant and more preferably 80 to 100% by mass.
[0059] In the mixture of difluoromethane (R32) and pentafluoroethane
(R125), the mass ratio (R32iR125) can be controlled to fall within the
range of, for example, 40 to 70160 to 30. Of these, a mixlure having a
10 mass ratio (R32iR125) of 60140, a mixture (R410A) having a mass ratio
of 50150 and a mixture (R410B) having a mass ratio of 45/55 are
suitably used.
[0060] In the mixture of difluoromethane (R32) pentafluoroethane
(R125) and 1,1,1,2-tetrafluoroethane (R134a), the mass ratio
15 (R32&125/R134a) can be controlled to fall within the range of, for
example, 15 to 3515 to 40140 to 70. Of these, a mixtuse having a Inass
ratio @32&125/R134a) of 30/10/60, a mixture (R407C) having a mass
ratio of 23125152 and a mixture (R407E) having a mass ratio of 25/15/60
are suitably used.
20 [0061] In the mixture of pentafluoroethane (R125),
1,1,1,2-tetrafluoroethane (R1342) and l,l,l-tsifluoroethane (R143a), the
mass ratio (R125/R134a/R143a) can be controlled to fall within the
range of, for example, 35 to 5511 to 15/40 to 60. Of these, a mixture
(R404A) having a mass ratio (R125/R134a/R143a) of 44/4/52 is
25 suitably used.
[0062] As a refiigerant, is., an unsaturated fluorinated hydrocarbon
(HFO), fluoropropene having 3 to 5 fluorhe atoms is preferable and at
least one element or a mixture of two or more elements selected fi.o~n,
1,2,3,3,3-pentafluoropropene (HFO-1225ye),
1,3,3,3-tetrafluoropropenes (HFO-1234ze), 2,3,3,3-tetrafluoropropenes
5 (WO-1234~0, 1,2,3,3-tet~afluoropropenes (HFO-1234ye) and
3,3,3-trifluoropropenes (HFO-12434 is preferable. In view of
physical propelties of a refrigerant, at least one element or a mixture of
two or Inore elements selected fiom HFO-1225ye, HFO-1234ze and
HFO-1234yf, is preferable.
10 [0063] The hydrocarbon refrigerant is preferably a hydrocarbon having
1 to 5 carbon atoms. More specifically, examples of the hydrocarbon
refrigerant include methane, ethylene, ethane, propylene, propane
(R290), cyclopropane, n-butane, isobutane, cyclobutane, methyl
cyclopropane, 2-methylbutane, n-pentane or a mixture of two types or
15 more of these. Of these, a substance present in a gaseous state at 2S°C,
1 atm is preferably used, and propane, n-butane, isobutane,
2-methylbutane or a mixture of these, is preferable.
[0064] In addition to the above refrigerant, another refrigerant may be
used appropriately in combination. Examples of the "another
20 refrigerant" include anotlier saturated fluorinated hydrocarbon
refiigerant, a fluorinated ether refiigerant such as perfluoro ether, a
bis(tsifluoromethy1) sulfide refiigerant, tsifluoroiodomethane refrigerant
and a natural refiigerant such as ammonia.
[0065] Examples of the "another saturated fluorinated hydrocarbon
25 refigerant" include a saturated fluorinated hydrocarbon having 1 to 3
and preferably 1 to 2 carbon atoms. More specifically, examples of the
saturated fluorinated hydroca~bon include a single substance or a
mixture of two or niore substances selected from pentafluoroethane
(R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tctrafluoroethane
(R134a), 1 ,l,l-trifluoroethane (R143a), 1,l -difluoroethane (R152a),
5 fluoroethane (R161), 1,1,1,2,3,3,3-heptafluoropropane (R227ea),
1 ,1, 1 ,2,3,3-hexafluoropropane (R236ea), 1, 1,1,3,3,3-hexafluoropropane
(R236fa), 1,1,1,3,3-pentafluoropropane (R245fa) and
1,1,1,3,3-pentafluorobutane (R365mfc).
[0066] A refiigerating machine oil is usually mixed with a refi-igerant
10 and present in the form of a working fluid composition for a
refrigerating machine in refrigerating air conditioning machines. The
content of a refi-igerating machine oil in the working fluid composition
for a refrigerating machine, which is not particularly limited, is 1 part by
mass or more, more preferably 2 parts by mass or more; and also
15 preferably 500 parts by mass or less and more preferably 400 parts by
mass or less based on 100 parts by mass of the refi-igerant.
[0067] The refi-igerating machine oil and working fluid composition for
a refrigerating machine are suitably used in air-conditioners having a
reciprocating or rotary hermetic compressor, refrigerators, open or
20 closed type car air-conditioners, dehumidifiers, water heaters, freezers,
refrigeratcd warehouses, vending machines, showcases, cooling systems
for chemical plants and machines having a centrifugal compressor.
Examples
[0068] Now, the present invention wiU more specifically described by
25 way of Examples; however, the present invention is not limited to the
following Examples.
[0069] Base oils having compositions and propel-ties show11 in 'I'ables 1
to 3 were used. The abbreviations in Tables I to 3 represent the
following nlonomers.
AC2: ethyl aciylate
AnC4: n-butyl aciylate
AiC4: 2-methylpropyl ac~ylate
AC3: propyl acsylate
MCI : methyl methacrylate
AiC8: 2-ethylhexyl acsylate
MG: glycidyl methacrylate
MMOE: lnethoxyethyl methaclylate
AEOM: ethoxymethyl ac~ylate
[0070] Properties of individual base oils were evaluated by the
following methods.
15 Mn, MwIMn: Using tetrahydrofuran as a solvent, a sample was
diluted to prepare a sample solution having a concentration of 1% by
mass. The sample solution was subjected to analysis by a GPC
apparatus (Waters AUiance2695). Using a column (an analyzable
molecular weight of 100 to 10000) at a solvent flow-sate of I mumin,
20 analysis was carried out by a refractive index detector. Note that,
using polystyrene whose molecular weight was knowg, as a standard,
the relationship between the column retention time and the n~olecular
weight was separately obtained to prepare a calibration curve iu
advance. Based on the calibration curve, the nlolecular weight was
25 determined fiom the obtained retention time.
Kinematic viscosity and viscosity index: JIS K2283: 1993
Pour point: JIS K2269: 1987
Flash point: JIS K2265-4: 2007
Autoignition point: ASTM E659-1978
[0071] [Table I]
Pour point ["C] <-45 -45 <-45 -40 1 -35 1
~
-
Mn
MwMn
Type of nionolner
Mola ratio of
monomers
1 B o 1 Bas oil 1 a oil 1 B e Base oil
9 1 10 1
- -
13asc oil
1
530
1.98
AC2
100
-
-
-
Kinenlatic
viscosity
[ d s ]
I
Type of mo~~omer I MCl I MCllAiC8 I MGlAC2 I MMOEdAiC4 I AEOM
40°C
100°C
Flash point ["C] 1 231 1 240
13ase oiI
2
1000
I .70
AnC4
100
150.4
17.1
Viscositv index 124
COO721 [Table 21
235
Autoignition point ["C] 381
[~utoi~nitipoonin t ["C] 1 387 1 391 1 399 387 39 3
Base oil
3
750
1.11
AiC4
100
25 1
379 402
Molar ratio of
monomeis
263
390 412
100
w
-
< -45
Kinematic
viscosity
[mm2/s]
Base oil
4
1510
1 .SO
AC21A-n C4JAiC4
80/10110
-
-
40°C
100°C
Base oil
5
2950
1.81
AC2lAC3
20180
-
80120
-
"
-
< -45
Viscosity index
Pour point ["C]
10190
-
-
-
< -45
50150
-
-
-40
100
-
-
-3 5
FP15-0152-00
roo731 [Table 31
Base oil 11 Base oil 12
Mu 290 3060
Mwhh 1.25 1.75
Type of monomer AC2IAnC4lAiC4 AC21AnC4/A-iC
Molw ratio of
monome1's 80/10/10 80/10/10
Kinematic 1400~
scosity I I
nm2/s1 100°C . .
Viscosity index
Pour point r°Cl < -45
Flas11 point rC] 238 26 1
Autoignition point YC] 389 397
Base oil 13 Base oil 14
[0074] Using the aforemetitioned individual base oils and the following
additives, refiigerating machine oils having compositions shown in
Tables 4 to 7 were prepared. Individual refrigerating machine oils
5 were subjected to the refrigerant compatibility test and antiwear
properly test shown below. The results are shown in 'Tables 4 to 7.
Additive 1: 2,6-di-tert-butyl-p-cresol
Additive 2: Tricresyl phosphate
Additive 3: Glycidyl neodecanoate
10 Additives 4: 2-ethylhexyl glycidyl ether
[0075] (Refrigerant compatibility test)
In accordance with JIS I(2211: 2009 "Test method for
compatibility with refiigermt" of "refrigerating machine oil", 10 g of a
refrigerating machine oil was blended with 10 g of a
15 difluoromethane/pentafluoroethane mixture (mass ratio 50150)
(R410A), difluoromethane (R32), 2,3,3,3-tetrafluoropropene
(HFO-1234yf), propane (R290) or carbon dioxide (C02), and then
whether a reftigerant and the refrigerating machinc oil werc ~nuttrally
dissolved at 0°C was observed. Note that, in the Tables, "compatible"
tneans that a refrigerant and the refrigerating machine oil were nlutually
dissolved; whereas, "separation" means that a reftigerant and the
5 refrigerating inacliine oil are separated into two layers.
[0076] (Antiwear property test)
An antiwear property test was perfomled using a
hyperbaric-atmosphere friction tester (system of rotation sliding of a
rotating vane material and a fixed disk material) manufactured by
10 SHINKO ENGINEERlNG CO., LTD., in the same atmosphere of a
rehigerant as created by a practical compressor. As the test condition,
any one of the following antiwear property tests-(1) to (5), which varied
depending upon the type of refrigerant, was enlployed.
Antiwear properly test-(1): R410A is used as a refrigerant and
15 the test vessel pressure is 1.6 MPa.
Antiwear property test-(2): R32 is used as a refiigerant and the
test vessel pressure is 1.6 m a .
Antiwear property test-(3): HFO-1234yf is used as a refrigerant
and the test vessel pressure is 1.6 MPa.
20 Antiwear property test-(4): n-hexane (added at 20% by volume
relative to a refrigerating machine oil; and used as an alternative
refrigerant because a hydrocarbon refrigerant such as R290 has security
fear) is used as a refrigerant and the test vessel pressure is controlled to
be slightly higher than atmospheric pressure.
Antiwear property test-(5): C02 is used as a refrigerant and the
test vessel pressure is 1.6 m a .
[0077] All antiwear property tests-(1) to (5) were carried out in
common conditions: an oil quantity of 600 ml, a test temperature of
90°C, a rotational speed of 550 ipm, a load load of 90 kgf, and test time
of one hour; and using SKI-T-51 as the vane material and FC250 as the
5 disk material. The ailtiwear property was evaluated based on the wear
depth of the vane material since the amount of wear of the disk material
was extremely low.
[007S] [Table 4:]
I
Refrigerant
Refrigerant compatibility
test
Antiwear property test
(wear depth, pm)
Refiigeriu~t
Refrigerant compatibility
test
Antimear propel@ test
(wear depth, pm)
Refrigerant
Refrigerant compatibility
test
R41OA
Compatible
9.3
R32
Compatible
10.1
HFO-1234yl
Compatible
12.2
R290
Compatible
11.8
C02
Compatible
10.1
Example 2
-
R4 1 OA
Compatible
8.1
R32
Compatible
8.5
EO-1234yl
Compatible
9.1
R290
Colnpatible
9.2
C02
Compatible
7.4
Example 3
.
R410A
Cotnpatible
7.3
R32
Compatible
8.4
HFO-1234y
Compatible
7.8
R290
Compatible
6.5
coz
Compatible
8.8
Example 4
-
R4lOA
Cotnpatible
6.6
R32
Co~npatible
7.6
PO-1234yf
Compatible
8.3
R2.90
Compatible
7.5
C02
Cotnpatible
9.1
-
R4 1 OA
Compatible
5.9
R32
Compatible
7.1
KFO-1234yl
Compatible
8.5
R290
Compatible
7.9
coz
Compatible
9.9
100791 [Table 51
Example 6
100
Example 7
011 total
amoollt of
R410A
Coiupatible
R4 1 OA
Compatible
R4lOA
Compatible
8.2
R32
Compatible
9.3
IFO-1234y:
Compatible
8.9
R4 1 OA
Refiigeraut compatibility Compatible
[test
hitiwear propetty test
(wear deptl~p, m)
TW2
Compatible
13.2
HFO-1234yf
Compatible
15.7
R32
Compatible
R32
Refrigerant compatibility Compatible
/test
Antiwear property test
(wear depth, p )
Refrigerant
Refrigerant cotopatibility Compatible Compatible
Antiwear property test
(wear depth, pm)
Refrigerant
Refrigerant compatibility . R290
Compatible
R290
Compatible
R290
Compatible
R290
Compatible
9.1
co2
Compatible
10.0
R290
Compatible
Antiwear property test
(wear depth, p )
coz
Compatible
coz
Compatible
coz
Refiigeraut compatibility Compatible
ltest
I Ailtiwear property test
(wear deptb, pm)
[0080] [Table 6 1 - . - .
total amount of
Antiwar property test
(wear depth, pn~)
Refrigerant
Refrigerant compatibility test
Autiwear property test
(wear depth, pm)
Rekigerant
Refrigerant compatibility test
Antiwear property test
(wear depth, pm) -
Rekigerant
Refrigerant compatibility test
Atiti\vear prope~tyte st
(wear depth, fi111)
8.1
HFO-1234yf
Co~npatible
10.2
R290
Compatible
10.8
COz
Compatible
7.1
8.1
HFO-1234yf
Compatible
8.8
R290
Compatible
8.9
COz
Compatible
7.1
' 6.7
HFO-1234yf
Compatible
6.5
R290
Compatible
5.2
coz
Compatible
6.4
[008 11 [Table 71
Coniposition
(mass % based on
total an~otulot f
refiigcrating Base oil 13
I Refrigerant cotnpatibility test
I Refrigerant cotnpatibility test
I ~etii~eracnomt patibility test
Antiwear property test
I Refrigerant compatibility test
Re£rigerant compatibility test
Antiwear property test
(wear depth, pm)
R410A
Conipatible
18.1
R32
Cotnpatible
17.1
HFO-1234yf
Compatible
21.5
R290
Compatible
16.9
co2
Compatible
15.3
:omnparative
Example 2
R4 1 OA
Separation
5.3
R32
Separatio~i
6.4
WO-1234yf
Separation
7.2
R290
Separation
8.3
co2
Separation
9.1
-. -01nparativt
Example 3
R410A
Compatible
9.1
R32
Separation
9.3
R290
Separation
8.9
co2
Compatible
8.3
100
R4 I 0A
Compatible
6.9
R32
Separation
8.8
:GO-1234yJ
Separation
9.9
R290
Separation

CLAIMS
1. A rekigerating machine oil conlprising, as a base oil, a polymer
having a structural unit represented by the following formula (1):
5 wherein R', R2 and R3, which may be the same as or different fiom each
other, represent a hydrogen atom or a hydrocarbon group; and K~
represents a hydrocarbon group or an organic group containing an
oxygen atom, and
having a iiunlber average molecular weight Mn of 300 or more and
10 3000 or less and a ratio of a weight-average molecular weight Mw to a
number average molecular weight Mn ( M w h ) of 1.10 or more and
2.00 or less, and
the refrigerating machine oil being used with a refrigerant
selected from the group consisting of difluoromethane, a mixture of
15 difluoromethane and pentafluoroethane, a mixture of difluoromethane,
pentafluoroethane and 1,1,1,2-tetrafluoroethane, a mixture of
pentafluoroethane, 1,!.,1,2-tetrafl.noroethane and I ,l,l-trifluoroethane,
unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.
2. The refrigerating machine oil according to claim 1, wherein
20 OR^ in the foxmula (I) is represented by the following forlnula (2):
-o(R~o),R~ (2)
wherein R5 represents a divalent hydrocarbon group or a divalent
hydrocarbon group containing an ether-bond oxygcn atom; R6
represents a hydrocarbon group; and m represents an integer of 0 or
more; wit11 the proviso that if m is 2 or more, a plurality of R~ may be
the same as or different from each other
5 3. A working fluid composition for a refrigerating machine
conlprising:
a refrigerating machine oil complising, as a base oil, a polymer
having a struck~raul nit represented by the following formula (1):
10 wherein R', R2a nd R ~w,h ich may be the same as or different fiom each
other, represent a hydrogen atom or a hydrocarbon group; and R~
represents a hydrocarbon group or an organic gsoup containing an
oxygen atom, and
having a number average molecular weight Mn of 300 or more and
15 3000 or less and a ratio of a weight-average molecular weight Mw to a
number average molecular weight Mn (Mw/Mn) of 1.10 or more and
2.00 or less; and
a refi-igerant selected from the group consisting of
ditluoromethane, a mixture of difluoromethane and pentafluoroethane, a
20 mixture of difluoromethane, pentafluoroethane and
1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane,
1,1,1,2-tetrafluoroethane and 1 ,l,l-tritluoroethane, unsaturated
hydrofluorocarbons, hydrocasbons and carbon dioxide.
4. The working fluid co~nposition for a refrigerating machine
according to claim 3, wherein -01X4in the for~nula(I ) is represented by
the following formula (2):
5 -o(R~o),R~ (2)
wherein R5 represents a divalent hydrocarbon group or a divalent
hydrocarbon group an ether-bond oxygen atom; R6 repsesents a
hydrocarbon group; and m represents an integer of 0 or more; with the
proviso that if m is 2 or more, a plurality of R5 may be the same as or
10 different from each other.
5. Use of a composition comprising a polymer as a base oil for a
refrigerating machine oil or a working fluid composition for a
refiigerating machine, wherein the polymer has a structural unit
represented by the following formula (1):
wherein R', R~a nd R ~w,h ich may be the same as or different from each
other, represent a hydrogen atom or a. hydrocarbon group; and R~
represents a l~ydrocarbon group or an organic group containing an
oxygen atom,
20 wherein the polymer has a number average molecular weight
Mn of 300 or more and 3000 or less and a ratio of a weight-average
molecular weight Mw to a number average molecular weight Mn
(MwJMn) of 1.10 or more and 2.00 or less,
wherein the refsigerating machine oil is used with a refi-igerant
selected from the group consisting of difluoronlethane, a mixture of
difluoronlethane and pentafluoroethane, a mixture of d ifluoromethane,
5 pentafluoroethane and 1,1,1,2-tetrafluoroethane, a mixture of
pentafluoroethane, 1,1,1,2-tetrafluoroethane and l,l, 1-trifluoroethane,
unsaturated hydrofluorocarbons, hydsocarbons and carbon dioxide, and
wherein the working fluid composition for a refrigerating
machine comprises a refiigerating machine oil and a refrigerant selected
10 fioin the group consisting of difluoromethane, a mixture of
difluoromethane and pentafluoroethane, a mixtuse of difluoromethane,
pentafluoroethane and 1,1,1,2-tetrafluoroethane, a mixture of
pentafluoroethane, 1,1,1,2-tetrafluoroethane and l,l, 1-trifluoroethane,
unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.
15 6. Use of a polymer for manufacturing a refrigerating machine oil
or a working fluid colnposition for a refiigerating machime, wherein the
polymer has a structural unit represented by the following formula (1):
wherein R', R' and R3, which may be the same as or different fionl each
20 otl~er, represent a hydrogen atom or a hydrocarbon group; and R4
represents a l~ydrocasbon group or an orgallic group containing an
oxygen atom,
wllerein the polymer has a number average molecular weight
Mn of 300 or more and 3000 or less and a ratio of a weight-average
lnolecular weight Mw to a number average molecular weight Mn
(MwMI) of 1.10 or Inore and 2.00 or less,
5 wherein the refrigerating machine oil is used with a refrigerant
selected fioin the group consisting of difluoromethane, a mixture of
difluoromethane and pentafluoroethane, a mixture of difluoromethane,
pentafluoroethane and 1 ,I, 1,2-tetrafluoroethane, a mixture of
pentafluoroethane, 1 ,I, 1,2-tetrafluosoethane and 1 ,l,l -trifluoroethane,
10 unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide, and
wherein the working fluid composition for a refrigerating
machine cotnprises a refrigerating maclline oil and a refrigerant selected
from the group consisting of difluoromethane, a mixture of
difluoromethane and pentafluoroetllane, a mixture of difluoromethane,
15 pentafluoroethane and 1 ,I ,1,2-tetrafluoroethane, a mixture of
pentanuoroethane, 1,1,1,2-tetrafluoroethane and I, 1,l-trifluoroethane,
unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.