DESCRIPTION
Title of inventioli: WORKING FLUID COlWOSITION FOR
REFRIGERATOR AND REFRIGERATION OIL
Technical Field
5 [0001] The present invention relates to a working fluid composition for
a refrigerating machine and a refrigerating machine oil.
Bacltground Art
[0002] CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons),
which have been used as refrigerants for conventional
10 refrigeration equipment, have become objects of regulations due to the
problem of recent ozone layer depletion, and HFCs
(hydrofluorocarbons) have come to be used as refrigerants instead of
them. Of HFC refrigerants, for example, R134a is normally used as a
refrigerant for automobile air conditioners. Fu~theimore, recently, use
15 of unsaturated fluorinated hydrocarbon refrigerants such as
FIFO-1234yf has been suggested, of which ozone depletion potential
(ODP) and global warming potential (GWP) are both very small and of
which thermodynamic properties, which are measures of refrigerant
performance, are equivalent to or greater than those of R13'4a.
20 [0003]tFor example, in Patent Literature 1, a refrigerating machine oil
that contains a polyol ester composed of a polyhydric alcohol selected
from pentaerythritol, trimethylolpropane, and neopentyl glycol and a
fatty acid and predetermined additives, as a refrigerating machine oil for
R134a, is disclosed, Alternatively, for example, in Patent Literature 2,
25 a refrigerating machine oil that contains, as the main component, an
ester of one or more selected from neopentyl glycol,
trimethylolpropane, pentaerythritol, and dipentaeqthritol and one or
more selected from monovalent fatty acids having 7 to 9 carbon atoms,
as a regigerating machine oil for HFO-1234yf, is disclosed.
Citation List
5 Patent Literature
[0004] Patent Literature I: Japanese Unexamined Patent Publication
NO. H09-189453
Patent Literature 2: International Publication WO No. 2010/029704
Summary of Invention
10 Technical Problem
[0005] However, according to the investigation of the present inventors,
even the refrigerating machine oils disclosed in Patent Literatures 1 and
2, there is still a room of improvement in terms of achieving both
lubricity (in particular, antiwear property) and stability.
15 [0006] The present invention has been made in consideration of such
circumstances and has an object to provide a working fluid composition
for a refrigerating machine and a refrigerating machine oil that is
capable of achieving both antiwear property and stability.
Solution to Problem
20 [0007] To solve the problem described ,above, the present invention
provides a working fluid composition for a refiigerating machine which
- ,.. contains a refrigerating machine oil colitaining an ester of a polyhydric
.. . . * : alcohol ana 'a'fatty acid, a carbodiimid&~compounda;n d a phosphorous
compound, and at least one regigerant selected from
25 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene, wherein the
polyhydric alcohol comtituting the ester contains p e n t a e ~ i t o la nd
dipentaerythritol, the fatty acid constituting the ester contains at least
one selected from fatty acids having 4 to 9 carbon atoms, and the
carbodiimide compound and the phosphorus cornpound satisfy the
conditions represented by the following formula (1).
5 [OOOS]
In the formula (I), Nc represents the number of carbodiimide groups per
molecule of the carbodiimide compound, Mc represents the molecular
weight of the casbodiimide compound, Wc represents the content of the
10 carbodiide compound based on the total amount of the refrigerating
machine oil, Np represents the number of phosphoins atoms per
molecule of the phosphorus compound, Mr represents the molecular
weight of the phosphosus compound, and Wp represents the content of
the phosphosus compound based on the total amount of the refiigerating
15 machine oil.
[0009] According to the above working fluid composition for a
refrigerating machine, it is possible to achieve both antiwear property
and stability at a high level. The ,present inventors infer the reason
why the effect is obtained as follows.
20 [OOlO] In the case of the working.fluid composition for a refrigerating
, ,- machine accortkig to the present 'invention, it is conceivable that both
antiwear property and stability can be achieved at a high level because
stability is sufficiently maintained as well as it is possible to sufficiently
suppress a phenomenon in which adsorption of the phosphorus
compound onto sliding portions is inhibited by the carbodiimide
compound by blending a phosphorus compound, which imparts
antiwear property so as to satisfy the above formula (I), and a
carbodiimide compound, which imparts stability, to the above specific
5 ester.
[0011] In the above estel; aspects of the following (i) and (ii) are
included:
(i) an ester containing a first ester that is an ester of pentaerythitol and
at least one fatty acid selected &om fatty acids having 4 to 9 carbon
10 atoms and a second ester that is an ester of dipentaerythritol and at least
one fatty acid selected flom fatty acids having 4 to 9 carbon atoms; and
(ii) an ester containing an ester obtained by reacting a mixture of a
polyhydsic alcohol containing pentaesythritol and dipentae~ythritowl ith
at least one fatty acid selected fkom fatty acids having 4 to 9 carbon
15 atoms.
[0012] Futthe~norei,n the above aspect of (i), it is preferable that the
content of the second ester be 10% by mass or more and 40% by mass
or less based on the total of the content of the first ester and the content
of the second ester.
20 [0013] It is preferable that the refrigerating machine oil further contain
0.1% by mass or more and 0.5% by mass or less of
2,6-di-test-butyl-p-cresol based on the total amount of the re&igerating
machine oil.
[0014] The present invention also provides a refiigerating machine oil
25 that contains an ester of a polyhydric alcohol and a fatty acid, a
carbodiimide compound, and a phospho~us compound, wherein the
polyhydric alcohol constituting the ester contains pentaerythritol and
dipentaerythritol, the fatty acid constituting the ester contains at least
one selected from fatty acids having 4 to 9 carbon atoms, the
carbodiimide compound and the phosphorus compound satisfy the
5 conditions represented by the following follnula (I), and the
refrigerating machine oil is used together with at least one refrigerant
selected from 1,1,1,2-tetraftuoroethane and 2,3,3,3-tetsafluoropropene.
[0015]
10 In the formula (I), Nc represents the number of carbodiimide groups per
molecule of the carbodiimide compound, Mc represents the molecular
weight of the carbodiimide compound, Wc represents the content of the
carbodiimide compound based on the total amount of the refrigerating
machine oil, Np represents the number of phosphoms atoms per
15 molecule of the phosphorus compound, Mp represents the molecular
weight of the phosphorus compound, and Wp represents the content of
the phosphorus compound based on the total amount of the refrigerating
machine oil.
Advantageous Effects of Invention
20 [0016] According to the present invention, it is possible to provide a ..
working 'flGd composition for a refrigerating machine and a
refrigerating machine oil that can achieve both antiwear property and
stability.
Description of Elnbodiments
[0017] Hereinbelow, preferred embodiments of the present invention
will be described in detail.
[0018] A refrigerating machine oil according to the present embodiment
contains an ester of polyhydric alcohol and a fatty acid, a carbodiimide
5 compound, and a phosphorus compound and is used together with at
least one refrigerant selected from 1,1,1,2-tetrafluoroethane and
2,3,3,3-tetrafluoropropene. The polyhydric alcohol constituting the '
ester contains pentaerythritol and dipentaerythritol, the fatty acid
constituting the ester contains at least one selected from fatty acids
10 having 4 to 9 carbon atoms, and the carbodiimide compound and the
phosphorus compound satisfy the conditions represented by the
following formula (1).
[0019]
15 In the formula (I), Nc represents the number of carbodiimide groups per
molecule of the carbodiimide compound, Mc represents the molecular
weight of the carbodiimide compound, Wc represents the content of the
carbodiimide compound based on the total amount of the refrigerating
machine oil, Np represents the number of phosphorus atoms per
20 molecule of the phosphoius compound, Mp represents the inolecular
weight of the phosplio~us compound, and Wp represents the content of
the phosphorus compound based on the total amount of the refrigerating
machine oil.
[0020] A working fluid composition for a rekigerating machine
according to the present embodiment contains a refrigerating machine
oil that comprises an ester of a polyhydsic alcohol and a fatty acid, a
ca~bodiimidec ompound, and a phospholus compound, and at least one
refrigerant selected from 1,1,1,2-tetsafluoroethane and
5 2,3,3,3-tetrafluoropropene. The polyhydric alcohol constituting the
ester contains pentaesythsitol and dipentaerythsitol, the fatty acid
constituting the ester comprises at least one selected from fatty acids
having 4 to 9 carbon atoms, and the carbodiimide compound and the
phosphorus compound satisfy the conditions represented by the above
10 formula (1). In the working fluid composition for a refrigerating
machine according to the present embodiment, an aspect containing the
refrigerating machine oil according to the present embodiment and at
least one refiigerant selected from 1,1,1,2-tetrafluoroethane and
2,3,3,3-tetsafluoropropene are included.
15 [0021] The rekigerating machine oil according to the present
embodiment contains an ester of a polyhydric alcohol and a fatty acid as
a base oil. The polyhydric alcohol constituting the ester contains
pentaelytbsitol and dipentaesyhitol, and the fatty acid constituting the
ester contains at least one selected £tom fatty acids having 4 to 9 carbon
20 atoms.
[0022] In the above ester, aspects of the following (i) and (ii) are
included: .,
(i) an ester corifaiiiing a first ester that is an ester of pentaesythritirl and
at least one fatty acid selected from fatty acids having 4 to 9 carbon
25 atoms and a second ester that is an ester of dipentaerythritol and at least
one fatty acid selected fiom fatty acids having 4 to 9 carbon atoms; and
(ii) an ester containing an ester obtained by reacting a mixture of a
polyhydric alcohol containing pentaerythritol and dipentaerythritol with
at least one fatty acid selected from fatty acids having 4 to 9 carbon
atoms.
5 [0023] It is preferable that the above ester contain a first ester that is an
ester of pentaerJrthrito1 and at least one fatty acid selected from fatty
acids having 4 to 9 carbon atoms and a second ester that is an ester of
dipentaerythlitol and at least one fatty acid selected from fatty acids
having 4 to 9 carbon atoms, The content of first ester is preferably
10 60% by mass or more, more preferably 65% by mass or more, still more
preferably 70% by mass or more, and also, preferably 90% by mass or
less, more preferably 85% by mass or less, still more preferably 80% by
mass or less, based on the total of the content of the first ester and the
content of the second ester. The content of the second ester is
15 preferably 10% by mass or more, more preferably 15% by mass or
more, still more preferably 20% by mass or more, and also, preferably
40% by mass or less, more preferably 35% by mass or less, still more
preferably 30% by mass or less, based on the total of the content of the
first ester and the content of the second ester. When the contents of the
20 first este~an d the second ester is withim the above range, it is possible to
sufficiently ensure the antiwear property.
[0024] The content of the above ester is preferably 70% by mass or
more, more preferhbly 80% by mass or more, still more pref61ably 90%
by mass or more based on the total amount of the refiigesating machine
25 oil, w om the viewpoint of being excellent in various performance such
as lubricity, refrigerant compatibility, thermal and chemical stability,
and electrical insulation. The content of the above ester can be 99% by
mass or less based on the total amount of the refrigerating machine oil.
[0025] As the polyhydric alcohol, other polyhydric alcohols may be
used in addition to pentae~witola nd dipentaesythsitol. As the other
5 polyhydric alcohol, it is possible to use a polyhydric alcohol having 2 to
6 hydroxyl groups, for example. The content of the other polyhydric
alcohol can be 50 mol% or less based on the total amount of the
polyhydric alcohol constituting the ester.
[0026] Specific examples of a divalent alcohol (diol) include ethylene
10 glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol,
1,2-butanediol, 2-metl1yl-1,3-propanediol, 1,5-pentanediol, neopentyl
gl~ml, 1,6-hexanediol, 2-ethyl-2-methyl-l,3-propanediol,
1,7-heptanediol, 2-methyl-2-propyl- l,3-propanediol,
2,2-diethyl- 1,3-propanediol, 1,8-octanediol, 1,9-nonanediol,
15 1,lO-decanediol, 1,ll-undecanediol, and 1,12-dodecanediol.
[0027] Specific examples of a trivalent or more alcohol include
polyhydric alcohols, such as tsimethylolethane, trimethylolpropane,
trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane),
hi-(pentaerythritol), glycerin, polyglycerin (dimes or tsimer of glycerin),
20 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol-glycerin . condensates,
adonitol, arabitol, xylitol, and mannitol, saccharides, such as xylose,
arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose,
sorbose, and ce'llobiose, and partially etherified produ&s thereof. Of
these, hindered alcoliols, such as neopentyl glycol, tsimethylolethane,
25 tsimethylolpropane, trimethylolbutane, di-(trimethylolpropane), and
tri-(tsimnethylolpropane) are preferable.
[0028] Examples of thc fatty acids having 4 to 9 carbon atoms
specifically include linear or branched butanoic acids, linear or
branched pentanoic acids, linear or branched hexanoic acids, linear or
branched heptanoic acids, linear or branched octanoic acids, and linear
5 or branched nonanoic acids. Of these, fatty acids having a branch at
the a-position and/or the P-position, and, for example,
2-methyl-propanoic acid, 2-methyl-butanoic acid, 2-methyl-pentanoic
acid, 2-methyl-hexanoic acid, 2-ethyl-pentanoic acid,
2-methyl-heptanoic acid, 2-ethyl-hexanoic acid, and
10 3,5,5-trimethyl-hexanoic acid ase preferable. Additionally, mixed
acids of Zmnethyl propanoic acid and 3,5,5-trimethyl hexanoic acid and
mixed acids of 2-ethyl hexanoic acid and 3,5,5-trimethyl hexanoic acid
are more preferable, and mixed acids of 2-ethyl hexanoic acid and
3,5,5-trimethyl hexanoic acid are still more preferable.
15 [0029] As the fatty acid, in addition to fatty acids having 4 to 9 carbon
atoms, it is possible to use other fatty acids. . Examples of the other
fatty acids include fatty acids having 10 to 24 carbon atoms. The
content of the other fatty acid can be 50 mol% or less based on the total
.amount of the fatty acid constituting the ester.
20 [0030] Examples of the other fatty acids more specifically include
linear or branched decanoic acids, linear or branched undecanoic acids,
I linear or branched dodecanoic acids, linear or branched tridecanoic
acids, linear or branched tetradecanoic acids; ginear or branched
pentadecanoic acids, linear or branched hexadecanoic acids, linear or
25 branched heptadecanoic acids, linear or branched octadecanoic acids,
linear or branched nonadecanoic acids, linear or branched icosanoic
acids, linear or branched heneicosanoic acids, linear or branched
docosanoic acids, linear or branched tricosanoic acids, and linear or
branched tetracosanoic acids.
[003 11 The ester according to the present embodiment may be a partial
ester in which some hydroxyl goups of the polyhydric alcohol are not
esterified and remains as the hydroxyl groups, may be a complete ester
in which all the hydroxyl groups are esterified, or may be a mixture of a
partial ester and a complete ester. The hydroxyl value of the ester is
preferably 10 mg KOWg or less, more preferably 5 mg KOHlg or less,
still more preferably 3 mg KOWg or less.
[0032] The base oil may comprise other base oil in addition to the ester
according to the present embodiment. As the other base oil, cxamples
include hydrocarbon oils, such as mineral oils, olefin polymers,
naphthalene compounds, and alkylbenzenes, ester base oils other than
the esters according to the present embodiment, synthetic oils composed
of a compound having oxygen atoms, such as polyglycols, polyvinyl
ethers, ketones, polyphenyl ethers, silicones, polysiloxanes, and
perffuoroethers. As the synthetic oil composed of a compound having
oxygen atoms, polyglycols, polyvinyl ethers, and ketones are preferably
. used of above oils. The content of the other base oil can be 50% by
mass or less based on the total amount of the base oil.
[0033] The kinematic viscosity of the base oil-at 40°C can be preferably
3 mm2is or more, more preferably 4 mtr!/s or more, still more
preferably 5 mm2/s or more, and preferably 1000 mm2/s or less, more
preferably 500 m d s or less, still more preferably 400 mm2/s or less.
The kinematic viscosity of the base oil at 100°C can be preferably 1
mm2/s or more, more preferably 2 mmZ/s or more, and can be preferably
100 t n d s or less, more preferably 50 mm2/s or less.
[0034] The refrigerating machine oil according to the present
embodiment comprises a carbodiimide compound and a phosphorus
5 compound in addition to the oil described above. The carbodiimide
compound and the phosphorus compound satisfy the conditions
represented by the following formula (1).
[0035]
10 [0036] In the formula (I), Nc represents the number of carbodiimide
groups per moJecde of the carbodiimide compound, Mc represents the
molecular weight of the carbodiimide compound, Wc represents the
content of the casbodiimide compound based on the total amount of the
refrigerating machine oil (unit: % by mass), Np represents the number of
15 phosphorus atoms per molecule of the phosphorus compound, Mp
represents the molecular weight of the phospholvs compound, and Wp
- represents the content of the phosphoms compound based on the total
amount of the refrigerating machine oil (unit: % by mass).
COO371 Hereinbelow, description will be made by conveniently
2,O - assuming that the middle term of the fo~mula( I) is C/P (that is, C =
. . ., @'TJMc).Wc, 'P = (NpMP).Wp). C/P is '0.11 or more, it is preferable
that CP be 0.12 or more, and it is more preferable that CP be 0.15 or
more. By the fact that C/P is 0.11 or more, it is possible to enhance the
stability of the refrigerating machine oil. Additionally, CIP is 4.70 or
less, it is preferable that CP be 4.50 or less, and it is more preferable that
CP be 3.90 or less. By the fact that C@ is 4.70 or less, since it is
possible to sufficiently exert the hnction of the phosphoius compound
as an anti-wear agent, it is possible to enhance the antiwear property of
the refrigerating machine oil.
[0038] It should be noted that that in the case where the reffigerating
machine oil comprises a plurality of carbodiimide compounds, Ci =
(N&)-Wc is calculated for each carbodiimide compound, and the
sum of all the Ci's calculated is taken as C, which is used in the foxmula
(1). Similarly, in the case where the reffigerating machine oil
comprises a plurality of phosphorus compounds, Pi = (NP/Mp).Wp is
calculated for each phosphorus compound, and the sum of all the Pi's is
taken as P, which is used in the formula (1).
[0039] As the carbodiiuzide compound, which is not particularly
limited, for example, it is possible to use dialkylcarbodiimides,
diphenylcarbodiimide, and bis(alky1phenyl)carbodiimides.
[0040] Examples of the alkylcarbodiimide include
diisopropylcarbodiimide and dicyclohexylcarbodiirnide.
[0041] Examples of the bis (alkylpheny1)carbodiimide include
ditolylcarbodiimide, bis(isopropylphenyl)carbodiimide, bis-
(diisopropylphenyl)carbodiimide, bis(triisopropylphenyl)carbodiimide,
bis(butyIphenyl)carbodiimide, bis(dibutylphenyl)carbodiimide, and
bis(nony1phenlj;l)carbodiimide.
[0042] The content of the carbodiimide compound, which may be set as
appropriate so as to satisfy the conditions represented by the above
formula (I), is preferably 0.01% by mass or more, more preferably
0.05% by mass or more, still more preferably 1.0% by mass or more,
and also, preferably 10% by mass or less, more preferably 8% by mass
or less, still more preferably 5% by mass or less, based on the total
amount of the refsigerating machine oil coinposition.
5 [0043] Examples of the phosphoms compound (also referred to as a
"phospholus-based additive" or a "phosphosus-based anti-wear agent")
include, but not particularly limited to, phosphoric esters, acidic
phosphoric esters, thiophosphates, amine salts of acidic phosphoric
esters, chlorinated phosphoric esters, and phosphite esters. These
10 phosphorus compounds may be used singly, or two or more of these can
be used in combination.
[0044] Examples of the phosphoric ester include tributyl phosphate,
tripentyl phosphate,. tsihexyl phosphate, triheptyl phosphate, trioctyl
phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate,
15 tsidodecyl phosphate, tritsidecyl phosphate, tsitetradecyl phosphate,
tsipentadecyl phosphate, tsihexadecyl phosphate, triheptadecyl
phosphate, t~ioctadecyl phosphate, trioleyl phosphate, triphenyl
phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl
phosphate, and xylenyl diphenyl phosphate.
20 [0045] Examples of the acidi~ph osphoric ester include monobutyl acid .. ~.
phosphate, monopentyl acid phosphate, monohexyl acid phosphate,
monoheptyl acid phosphate, monooctyl acid phosphate, monononyl acid ,. ,< -
. phosphate, mono'decyl acid phosphate, monoundecyl acid phosphate, . Ci
monododecyl acid phosphate, monotridecyl acid phosphate,
25 inonotetsadecyl acid phosphate, monopentadecyl acid phosphate,
monohexadecyl acid phosphate, monolieptadecyl acid ,phosphate,
monooctadecyl acid phospllate, monooleyl acid phosphate, dibutyl acid
phosphate, dipentyl acid phosphate, dihexyl acid phosphate, diheptyl
acid phosphate, dioctyl acid phosphate, dinonyl acid phosphate, didecyl
acid phosphate, diundecyl acid phosphate, didodecyl acid phosphate,
5 ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid
phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate,
dioctadecyl acid phosphate, and dioleyl acid phosphate.
[0046] Examples of the thiophosphoric ester include tributyl
phosphorothioate, tripentyl phosphorothioate, trihexyl
10 phosphorothioate, triheptyl phosphorothioate, trioctyl phosphorothioate,
trinonyl phosphorothioate, tridecyl phosphorothioate, triundecyl
phosphorothioate, tridodecyl phosphorothioate, tritridecyl
p h o s p h ~ ~ o a t e , tritetradecyl phosphorothioate, tripentadecyl
phosphorothioate, trihexadecyl phosphorothioate, triheptadecyl
15 phosphorothioate, trioctadecyl phosphorothioate, trioleyl
phosphorothioate, triphenyl phosphorothioate, tricresyl
phosphorothioate, trixylenyl phosphorothioate, cresyl diphenyl
phosphorothioate, and xylenyl diphenyl phosphorothioate.
[0047] Examples of the amine salt of the acidic phosphoric ester
20 include salts of the above acidic phosphoric ester with an amine such as
methylamine, ethylamine, propylamine, butylamine, pentylamine,
hexylatnhe, heptylamine, octylamine, dimethylamine, diethylamine,
dipropylamine, dibutfiamine, dipentylamine, dihexylamine, '-
diheptylamine, dioctylamine, trimethylamine, triethyla~nine,
25 tripropylamine, tributylatnine, tripentylamine, trihexylarnine,
triheptylamine, and trioctylamine.
[0048] Examples of the chlorinated phosphoric ester include
tris-dichloropropyl phosphate, tris-chloroethyl phosphate,
tris-chlorophenyl phosphate, and polyoxyalkylene-bis[di(chloroalkyl)]
phosphate. Examples of the phosphite ester include dibutyl phosphite,
5 dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl
phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite,
didodecyl phosphite, dioleyl phosphite, diphenyl phosphite, dicresyl
phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite,
triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl
10 phosphite, triundecyl phosphite, tridodecyl phosphite, trioleyl phosphite,
triphenyl phosphite, and tricresyl phosphite.
[0049] The content of the phospho1.u~ compound, which may be set as
appropriate so as to satisfy the conditions represented by the above
formula (I), is preferably 0.1% by mass or more, more preferably 0.2%
15 by mass or more, still more preferably 0.3% by mass or more, and also,
preferably 2.4% by mass or less, more preferably 2.0% by mass or less,
still more preferably 1.0% by mass or less, based on the total amount of
the refrigerating machine oil.
[0050] It is preferable that the refrigerating machine oil according to the
20 present embodiment further contain 2,6-di-test-butyl-p-cresol. The
content of 2,6-di-tert-butyl-p-cresol is preferably 0.1% by mass or more,
more preferably 0.15% by mass or more, still more preferably 0.2% .by,
mass or more, and:.also, preferably 0.5% by mass or less, more,
preferably 0.35% by mass or less, still more preferably 0.3% by mass or
25 less, based on the total amount of the refiigesating machine oil. When
the content is the above lower limit or more, it is possible to further
enhance the stability of the reeigerating machine oil. In contrast,
when the content is the above upper limit or less, it is possible to
suppress the coloring of the refrigerating machine oil due to
2,6-di-tert-butyl-p-cresol,
[0051] Also, the refrigerating machine oil according to the present
embodiment can contain conventionally known additives for
refkigerating machine oils in order to hsther enhance its performance.
Examples of such additives include phenol-based antioxidants, such as
bisphenol A, 2,6-di-teit-butyl-4-methylphenol, and 4,4'-methylene
bis(2,6-di-test-butylphenol), arnine-based antioxidants, such as
phenyl-a-naphthylamine and N,N-di(2-naphthy1)-p-phenylenediamine,
extreme pressure agents, such as chlorinated paraffin and dibenzyl
disulfide, oiliness agents, such as acyl glycerol and glyceryl ether,
antifoaming agents, such as dimethylpolysiloxane and
perfluoropolyether-modified polysiloxane, metal deactivators, such as
benzotriazole, 2,s-dialkylmercapto- 1,3,4-thiadiazole, and
N,N1-disalicylidene-l,Zdiaminopropane, antiwear agents, such as
triphenyl phosphate, tricresyl phosphate, and tricresyl
phosphorothionate, viscosity index improvers, such as
polymethacrylate, olefin copolymers, and polyisobutylene, pour point
depressant, such as alkylated aromatic compounds and ethylene-vinyl
acetate copolymers PVA), and detergent dispersants, such as hide
succinate and- succinic esters. One of these additives may be' used
singly, or two or more of these additives may be used in combination.
The content of these additives is not particularly limited, but is
preferably 0.01% by mass or more, more preferably 0.05% by mass or
more, still more preferably 0.1% by mass or more, and also, preferably
10% by mass or less, more preferably 5% by mass or less, still more
preferably 3% by mass or less, based on the total amount of the
refrigerating machine oil.
5 [0052] The volume resistivity of the refrigerating machine oil is not
particularly limited, but can be preferably 1.0 x 1012 Ocm or more,
more preferably 1.0 x 1013 CLcm or more, still more preferably 1.0 x
1014 Qncm or more. In particular, in the case of use for a hermetic-type
refrigerating machme, high electrical insulation tends to be required.
10 The volume resistivity in the present invention means the value
measured at 25°C in compliance with JIS C2101 "Testing methods of
electrical insulating oils".
[0053] The moisture content of the reEgerating machine oil is not
particularly limited, but can be preferably 200 ppm or less, more
15 preferably 100 ppm or less, still more preferably 50 ppm or less based
on the total amount of the refkigerating machine oil composition.
Particularly, in the case of use for a hermetic-type refl-igerating machine,
it is required that the moisture content be low, from the viewpoint of the
idtuence on the thermal/chemical stability and the electrical insulation
20 propetty of the refrigerating machme oil.
[0054] The acid value of the refrigerating machine oil is not particularly
limited, but can be preferably 0.1 mg KOWg or less, more preferably
0.05 tng W g or less. The hydroxyl value OF the refrigerating
machine oil is not particularly limited, but can be preferably 5.0 mg
25 KOHg or less, more preferably 2.0 mg KOWg or less. When the acid
value and the hydroxyl value of the refkigerating machine oil satisfy the
above conditions, it is possible to further prevent corrosion of the metal
used in a refrigerating machine or piping. The acid value in the
present invention means the acid value measured in compliance with JIS
K2501 "Petroleum products and lubricants - Determination of
5 neutralization number", and the hydroxyl value in the present invention
means the hydroxyl value measured in compliance with JIS KO070
"Test methods for acid value, saponification value, ester value, iodine
value, hydroxyl value and unsaponifiable matter of chemical products".
COO551 The ash content of the refrigerating machine oil is not
10 particularly limited, but can be preferably 100 ppm or less, more
preferably 50 ppm or less, in order to increase the thermallchemical
stability of the refrigerating machine oil and to suppress the occurrence
of sludge or the like. The ash content in the present invention means
the value of the ash content measured in compliance with JIS K2272
15 "Crude oil/petroleum product ash content and sulfated ash content test
method".
[0056] The pour point of the refrigerating machine oil can be preferably
-10°C or less, more preferably -20°C or less, still more preferably -30°C
or less. The pour point in the present invention means the pour point
20 measured in compliance with JIS K2269.
[0057] The refi-igerating machine oil according to the present
smbodiment is used together with at least one refitgerant selected from
T;1,1,2-tetrafluoroethane (R134a) and 2,3;3;3-tetrafluoropropene
(HFO-1234yf). The working fluid composition for a refrigerating
25 machine according to the present embodiment contains at least one
refrigerant selected from 1,1,1,2-tetrafluoroethane (R134a) and
2,3,3,3-tetrafluoropropene (HFO-1234yf). Such refrigerants may take
aspects of a refrigerant composed only of R134a, of a refrigerant
composed only of WO-l234yf, or of a mixed refrigerant of R134a and
HFO-1234yf.
5 [0058] A composition that contains an ester of a polyhydric alcohol and
a fatty acid, a carbodiimide compound, and a phosphorus compound
and in which the polyhydsic alcohol constituting the ester contains
pentaewhritol and dipentaesythritol, the fatty acid constituting the ester
contains at least one selected fsom fatty acids having 4 to 9 carbon
10 atoms, and the carbodiimide compound and the phosphorus compound
satisfy the conditions represented by the above formula (1) is suitably
used as a component of a refrigerating machine oil used together with at
least one. . refrigerant. selected from 1,1,1,2-tetrafluoroethane and
2,3,3,3-tetrafluoropropene or as a component of a working fluid
15 composition for a rekigerating machine that contains the refrigerating
machine oil and at least one refrigerant selected fsom
1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene.
[0059] A composition that contains an ester of a polyhydsic alcohol and
- a fatty acid, a carbodiimide compound, and a phosphorus compound
20 .. . and in which the polyhydric alcohol constituting the ester contains
- pentaeiythritol and dipentaetythritol, the fatty acid constituting the ester
.. <. ... contains at least one selected fsom fatty acids having 4 to 9 carbon
.: % 'atoms, aria'tlie carbodiimide compound and-the phosphorus compound
satisfy the conditions represented by the above formula (1) is suitably
25 used for manufacture of a component of a refrigerating machine oil used
together with at least one refrigerant selected from
1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene or for
manufactuse of a working fluid composition for a refrigerating machine
that contains the refrigerating machine oil and at least one refrigerant
selected from 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetsafluoropropene.
[0060] The refrigerant used together with the refrigerating machine oil
according to the present embodiment or the refrigerant contained in the
working fluid composition for a refrigerating machine according to the
present embodiment may contain other refrigerant in addition to at least
one refrigerant selected from R134a and HFO-1234yf. Examples of
other refrigerant include saturated fluorinated hydrocarbon refrigerants
other than R134a, unsaturated fluorinated hydrocarbon refrigerants
other than HFO-1234yf, fluorine-containing ether-based refrigerants,
such as perfluoroethers, bis(trifluoromethy1)sulfide rekigerants,
trifluoroiodomethane refrigerants, and natural refrigerant, such as
dimethyl ether, carbon dioxide, ammonia, and hydrocarbons.
[0061] The content of the refrigerating machine oil in the working fluid
composition for a refitgerating machine is not particularly limited, but
can be preferably 1 past by mass or more, more preferably 2 parts by
mass or more, and also, can be preferably 500 parts by mass or less,
more preferably 400 parts by mass or less, based on 100 pasts by mass
of the refrigerant.
[0062] The refrigerating machine oil and-the working fluid composition
for a refrigerating machine according .td the present embodiment are
preferably used in air conditioners or refsigerating machines having a
reciprocating or rotating closed compressor, or in open or closed
automobile air conditioners. The refrigerating machine oil and the
working fluid composition for a refrigerating machine according to the
present embodiment are preferably used in dehumidifiers, hot water
suppliers, cooling apparatuses, such as freezers, freezing-refrigerating
warehouses, vending machines, showcases, and chemical plants. The
5 refrigerating machine oil and the working fluid composition for a
refrigerating machine according to the present embodiment are also
preferably used in those having a centrifugal compressor.
Examples
[0063] Hereinbelow, the present invention will be described more
10 specifically based on examples and comparative examples, but the
present invention is not limited in any way by the examples below.
[0064] Examples 1 to 10 and Comparative Examples 1 to 201
In Examples 1 to 10 and Comparative Examples 1 to 20, base
oils 1, Al, A2, and B1 comprising an ester of apolyhydric alcohol and a
15 fatty acid shown in Table 1 and additives shown below were used to
prepare refrigerating machine oils of which composition is shown in
Tables 2 to 7. On the refrigerating machine oils prepared in Examples
1 to 10 and Comparative Examples 1 to 20, antiwear property test and
stability test were conducted.
20
100651 [Table 11
Rase oil number 1 A1
Polyllydric alcohol Negolpyecnotly l ~entaefllzitol
'ope
2-Ethylhexanoic 2-Methylpropanoit
acid acid
Fatty acid
A Mixing ratio
of fatty acid 100 35
(mol%)
Fatty acid
65
C1: Bis(diisopropylpheny1)carbodiimide
C2: Diisopropylcarbodiimide
5 Dl: Tricresyl phosphate
D2: Triphenyl phosphorothionate
El: 2,6-di-tert-butyl-p-cresol
[0067] (Antiwear property Test)
A High Pressure Ambience Friction & Wear Tester
10 manufactured by Shinko Engineering Co., Ltd. (rotation sliding mode
by a rotary vane member and a fixed disc member), which can achieve a
refrigerant atmosphere similar to that of an actual compressor, was used
,. for antiwear property test. The test conditions were oil amount: 600
ml, test temperature: 100°C, niunber of revolutions: 450 rpm, applied
15 load: 60 kgf, and test period: 1 hour. SKH-51 was used as the vane
member, and FC250 was used as the disc member. As the refrigerant,
(HFO-1234yf) was used, and the pressure inside the test vessel was 1.1
MPa. Antiwear property evaluation was conducted based on the wear
depth of the vane member because the mount of wear of the disc was
very small. The results obtained are shown in Tables 2 to 7.
5 [0068] (Stability Test)
The stability test was conductcd in compliance with JIS
K2211-09 (autoclave test). Specifically, 80 g of a sample oil of which
moistuse content had been adjusted to 100 ppm was weighed into an
autoclave. After the sample oil, catalysts (iron, copper, aluminum
10 lines, each in outer diameter of 1.6 mm x length of 50 mmn), and 20 g of
1,1,1,2-tetrafluoroethane (R134a) or 2,3,3,3-tetrafluoropropene
(HFO-1234yf) were sealed, the mixture was heated to 140°C, and the
appearance and acid value of the sample oil after 150 how were
evaluated (JISC2101). The results obtained are shown in Tables 2 to 7.
[0069] [Table 21
--
[0070] [Table 31
[0071] [Table 41
mass based on the
roo721 [Table 51 ~~ - - . . . . . . .
- - . . . . . 1 llxarnplc . 6 1 Example 7 1 Examp.l. e. 8. . 1-E .x.- a mple 9 . . 1 &. . ..G -. m. .
[0073] [Table 61
I I Cow. I comp. comp.
Example 14
Composition of
base oil (% by
mass, based on the
total amount of the
base oil)
Composition of
refrigerating
machine oil (% by
mass, based on the
total amount ofthe
Exampie 12
60
40
98.7
0.2
0.5
1
~1
A2
B1
Base oil
C1
C2
Dl
refrigerating
tnachine oil)
base oil (% by
mass, based on the
total amount of the
I I
Comp.
~xampie1 3 Exanlplc 15
60
40
98.95
0.05 -
0.5
Stability test
2Example 17 Example 18
Comp.
Example 16
D2
El
1 base oil) IB1
Acid value
fmeKOWe)
Composition of Base oil 95 93.4
reeigerating C1 5
~nachineo il (%by C2 4
mass, based on the
total amount of tho Dl 1
refrigerating D2 0.5
machiie oil) El 0.5 0.6
C/P 21.71 4.78
Refrigerant mo- HFOm4yr
i234yf
0.6
CR
Refrigerant
Antiwar property 1\7{ear depth
Stability test
0.01
0.38
mo-
1234yf
Antiwear property 6,7
test
No
deposition
0,03
Comp. Coq. Comp. Comp.
Example 19 Example 20 Example 21 Example 22
0.5
Wear depth
(m0.6 0.5 0.6 0.6
5.73 7.65 7.65 4.78
HFO- HFO- HFO- HFO-
0.10
mo-
1234yf
5.5
No
deposition
0.75
I I I
No No No No
deposition deposition deposition deposition
I I I
1
0.5 -.
21.71
HFO-
1234yf
7.1
No
deposition
0.01
1
0.5
0.5
0.5
27.14
HFO-
1234yf
7.5
No
deposition
0.01
16.29
mo-
1234yf
6.9
No
deposition
0.01

CLAIMS
1. A working fluid composition for a refrigerating machine,
comprising:
a sefiigerating machine oil comprising an ester of a polyhydric
5 alcohol and a fatty acid, a carbodiiinide compound, and a phospholus
compound; and
at least one refrigerant selected from 1,1,1,2-tetrafluoroethane
and 2,3,3,3-tetrafluoropropene;
wherein the polyhydric alcohol constituting the ester comprises
10 pentae~ythritoal nd dipentaerythritol,
the fatty acid constituting the ester comprises at least one
selected from fatty acids having 4 to 9 carbon atoms, and
the carbodiimide compound and the phosphorus compound
satisfy conditions represented by the following formula (1):
wherein, Nc represents a number of carbodiimide groups per molecule
of the carbodiimide compound, Mc represents a molecular weight of the
carbodiirnide compound, Wc represents a content of the carbodiimide
compound based on a total amount of the refiigeratine machine oil, Np
2;. --.
20 represents a number of phospholus atoms per m'blecule of the
phosphorus compound, Mp represents a molecular weight of the
phosphorus compound, and Wp represents a content of the phosphorus
compound based on a total amount of the refrigerating machine oil.
2. The working fluid composition for a refrigerating machine
according to claim 1, wherein the ester comprises a mixture of a first
ester that is an ester of pentaerythritol and at least one fatty acid selected
from fatty acids having 4 to 9 carbon atoms and a second ester that is an
5 ester of dipentaet-ythsitol and at least one fatty acid selected from fatty
acids having 4 to 9 carbon atoms.
3. The working fluid composition for a refrigerating machine
according to claim 2, wherein a content of the second ester is 10% by
mass or more and 40% by mass or less based on a total content of the
10 first ester and the second ester.
4. The working fluid composition for a refrigerating machine
according to any one of claims 1 to 3, wherein the refrigerating machine
oil further comprises 0.1% by mass or more and 0.5% by mass or less of
2,6-di-tert-butyl-p-cresol based on the total amount of the refrigerating
15 machine oil.
5. A refrigerating machine oil comprising:
an ester of a polyhydric alcohol and a fatty acid;
a carbodiimide compound; and
a phosphoius compound;
20 wherein the polyhydric alcohol constituting the ester comprises
pentaerythritol and dipentaerythsitol,
. , the fatty acid constituting the ester comprises at least one
sclected from fatty acids having 4 to 9 carbon atoms;
the carbodiimide compound and the phosphorus compound
25 satisfy conditions represented by the following formula (1):
wherein, Nc represents a number of carbodiimide groups per molecule
of the carbodiimide compound, Mc represents a molecular weight of the
carbodiimide compound, Wc represents a content of the carbodiimide
5 compound based on a total amount of the refrigerating machine oil, Np
represents a number of phosphorus atoms per molecule of the
phosphorus compound, Mp represents a molecular weight of the
phosphorus compound, and Wp represents a content of the phosphorus
compound based on a total amount of the refkigerating machine oil, and
10 the ref?igerating machine oil is used together with at least one
refrigerant selected from 1,1,1,2-tetrafluoroethane and
2,3,3,3-tetrafluoropropene.
6, Use of a composition for a refiigerating machine oil or a
working fluid composition for a refiigerating machine, the composition
15 comprising:
an ester of a polyhydric alcohol and a fatty acid;
a carbodiimide compound; and
a phosphorus compound,
wherein the polyhydric alcohol constituting the ester comprises
20 .- pentaeryt'hr'itol ana dipentaerythitol, -%
the fatty acid constituting the ester comprises at least one
selected £?om fatty acids having 4 to 9 carbon atoms,
the carbodiimide compound and the phosphorus compound
satisfy conditions represented by the following formula (1):
wherein, Nc represents a number of carbodiide groups per molecule
of the carbodiimide compound, Mc represents a molecular weight of the
carbodiimide compound, Wc represents a content of the carbodiimide
compound based on a total amount of the refrigerating machine oil, Np
represents a number of phosphorus atoms per molecule of the
phosphorus compound, Mp represents a molecular weight of the
phosphoms compound, and Wp represents a content of the phosphorus
compound based on a total amount of the refrigerating machine oil,
the reeigerating machine oil is used together with at least one
refrigerant selected &om 1,1,1,2-tetsafluoroethane and
2,3,3,3-tetrafluoropropene, and
the working fluid composition for a refrigerating machine
comprises the refrigerating machine oil and at least one refrigerant
selected from 1,1,1,2-tetrafluoroethane and 2,3,3,3 -tetrafluoropropene.
7. Use of a composition for manufacturing a refrigerating machine
oil or a working fluid composition for a refrigerating machine, the
composition comprising:
an ester of a polyhydric alcohol ar~da fatty acid;
a casbodiimide compound; and
a phosphorus compound,
wherein the polyhydric alcohol constituting the ester comprises
. .
pentaemhritol and dipentaemhritol, .;
' the fatty acid constituting the ester comprises at least one
selected horn fatty acids having 4 to 9 carbon atoms,
the carbodiimide compound and the phosphorus compound
5 satisfy conditions represented by the following formula (1):
wherein, Nc represents a number of carbodiimide groups per molecule
of the carbodiimide compound, Mc represents a moIecular weight of the
carbodiimide compound, Wc represents a content of the carbodiimide
10 compound based on a total amount of the refrigerating machine oil, Np
represents a number of phosphorus atoms per molecule of the
phosphorus compound, Mp represents a molecular weight of the
phosphorus compound, and Wp represents a content of the phosplloms
compound based on a total amount of the refrigerating machine oil,
15 the refrigerating machine oil is used together with at least one
refrigerant selected from - 1,1,1,2-- tetrafluoroethane and - .. 2,3,3,3-tetrafl~oropro~enaen, d .. .
the working fluid composition for a refrigerating machine
,* a ..~. comprises the refigerating machine oil and .at least one refrigerant , .?.~
-. .A.
. :'% i.20 . - selectea" horn 1,1,1,2-tetrafluoroeth5ihe and 2,3,3,3-tetrafluoropropene.