REFRIGERATOR OIL COMPOSITION AND REFRIGERATOR MIXTURE COMPOSITION

Abstract

A refrigerator oil composition with a base oil (A), and a first phosphorus compound (B). The first phosphorus compound (B) is a first phosphite ester (B1) represented by formula (1) and a second phosphite ester (B2) represented by formula (2):

(R.sup.11—O—).sub.n—PO—R.sup.12).sub.3-n   (1)

##STR00001##

A method of producing a refrigerator oil composition by mixing a base oil (A) with a first phosphorus compound (B). A refrigerator mixture composition includes the refrigerator oil composition and a refrigerant.

Claims

1. A refrigerator oil composition comprising a base oil (A), and a first phosphorus compound (B), wherein the first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite ester (B1) represented by formula (1) and a second phosphite ester (B2) represented by formula (2):
(R.sup.11—O—).sub.n—PO—R.sup.12).sub.3-n   (1) wherein in formula (1) R.sup.11 is an aromatic group represented by formula (1a), R.sup.12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms, and n is an integer of 1 to 3, wherein if n≥2, R.sup.11—O—'s may be the same or different from each other, and if n=1, —O—R.sup.12's may be the same or different from each other, ##STR00035## wherein in formula (1a) R.sup.13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms, m is an integer of 0 to 5, wherein if m≥2, R.sup.13's may be the same or different from each other, and the wavy line in the formula (1a) represents a position of bonding to an oxygen atom in R.sup.11—O—, ##STR00036## wherein in formula (2) each of R.sup.21 and R.sup.22 is independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.

2. The refrigerator oil composition according to claim 1, wherein m in the formula (1a) is an integer of 1 to 5.

3. The refrigerator oil composition according to claim 1, further comprising a second phosphorus compound (C), wherein the second phosphorus compound (C) is at least one selected from the group consisting of a phosphoric acid compound (C1) and an organic phosphine oxide compound (C2).

4. The refrigerator oil composition according to claim 1, wherein a phosphorus atom content is 200 ppm by mass to 1,500 ppm by mass based on a total amount of the refrigerator oil composition.

5. The refrigerator oil composition according to claim 1, wherein the base oil (A) comprises at least one selected from the group consisting of polyalkyleneglycols, polyvinylethers, a copolymer of poly(oxy)alkyleneglycol or its monoether, polyvinylether, polyolesters, and mineral oil.

6. A method of producing a refrigerator oil composition, the method comprising mixing a base oil (A) with a first phosphorus compound (B), wherein the first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite ester (B1) represented by formula (1) and a second phosphite ester (B2) represented by formula (2):
(R.sup.11—O—).sub.n—PO—R.sup.12).sub.3-n   (1) wherein in formula (1) R.sup.11 is an aromatic group represented by a following general formula (1a), R.sup.12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms, and n is an integer of 1 to 3, wherein if n≥2, R.sup.11—O—'s may be the same or different from each other, and if n=1, —O—R.sup.12's may be the same or different from each other, ##STR00037## wherein in formula (1a) R.sup.13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms, m is an integer of 0 to 5, wherein if m≥2, R.sup.13's may be the same or different from each other, and the wavy line in the formula (1a) represents a position of bonding to an oxygen atom in R.sup.11—O—, ##STR00038## wherein in the formula (2) each of R.sup.21 and R.sup.22 is independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.

7. A refrigerator mixture composition, comprising: the refrigerator oil composition according to claim 1; and a refrigerant.

8. The refrigerator mixture composition according to claim 7, wherein the refrigerant comprises at least one selected from the group consisting of an unsaturated fluorinated hydrocarbon compound, a saturated fluorinated hydrocarbon compound, hydrocarbon, carbon dioxide, and ammonia.

Description

EXAMPLES

[0374] The present invention will be described in detail with reference to the following Examples. However, the present invention is not limited to the following Examples.

[0375] <Properties of Base Oil (A)>

[0376] The 40° C. kinematic viscosity of a base oil (A) used in each of Examples and each of Comparative Examples was measured in accordance with JIS K 2283:2000.

[0377] <Details of Each Component Used for Preparing Refrigerator Oil Composition≥

[0378] The details of each component used for preparing a refrigerator oil composition are illustrated below.

[0379] 1. Base oil (A)

[0380] (1) PAG

[0381] polyoxypropyleneglycol monomethylether, 40° C. kinematic viscosity: 49 mm.sup.2/s

[0382] (2) PVE

[0383] copolymer of polyethyl vinylether and polyisobutyl vinylether (structural unit of ethyl vinylether: structural unit of polyisobutyl vinylether =9:1 (molar ratio)), 40° C. kinematic viscosity: 67 mm.sup.2/s

[0384] 2. First phosphorus compound (B)

[0385] (1) First phosphite ester (B1)-1

[0386] Isodecyldiphenyl phosphite (manufactured by JOHOKU CHEMICAL Co., Ltd., JPM-311, a compound represented by the following formula (1-1), phosphorus atom content: 8.1% by mass)

##STR00026##

[0387] The compound represented by the formula (1-1) corresponds to a compound in which n=2, two R.sup.11—O—'s are the same, and R.sup.12 is an isodecyl group in the general formula (1). Further, in the general formula (1a), m=0.

[0388] In the formula (1-1), “-iC.sub.10H.sub.21” means an isodecyl group. The same also applies to the following description.

[0389] (2) First phosphite ester (B1)-2

[0390] 2-ethylhexyldiphenyl phosphite (manufactured by JOHOKU CHEMICAL Co., Ltd., JPM-308, a compound represented by the following formula (1-2), phosphorus atom content: 8.6% by mass)

##STR00027##

[0391] The compound represented by the formula (1-2) corresponds to a compound in which n=2, two R.sup.11—O—'s are the same, and R.sup.12 is a 2-ethylhexyl group in the general formula (1). Further, in the general formula (1a), m=0.

[0392] (3) First phosphite ester (B1)-3

[0393] Phenyldiisodecyl phosphite (manufactured by Sakai Chemical Industry Co., Ltd., ChelexD, a compound represented by the following formula (1-3), phosphorus atom content: 7.1% by mass)

##STR00028##

[0394] The compound represented by the formula (1-3) corresponds to a compound in which n=1, two —O—R.sup.12's are the same, and R.sup.12 is an isodecyl group in the general formula (1). Further, in the general formula (1a), m=0.

[0395] (4) First phosphite ester (B1)-4

[0396] A reaction product of bis[2,4-bis(2-methylbutane-2-yl) phenyl]4-(2-methylbutane-2-yl)phenyl phosphite, 2,4-bis(2-methylbutane-2-yl)phenylbis[4-(2-methylbutane-2-yl)phenyl]phosphite, and tris[4-(2-methylbutane yl)phenyl]phosphite (manufactured by Addivant, WESTON (registered trademark) 705, a mixture of compounds represented by the following formula (1-4) to the following formula (1-7), phosphorus atom content: 4.9% by mass)

##STR00029##

[0397] The compound represented by the formula (1-4) corresponds to a compound in which n=3, and three R.sup.11—O—'s are the same in the general formula (1). Further, in the general formula (1a), m=1, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: a para position).

##STR00030##

[0398] The compound represented by the formula (1-5) corresponds to a compound in which n=3, and among three R.sup.11—O—'s, two are the same, and one is different in the general formula (1). Further, in the same two R.sup.11—O—'s, in R.sup.11 represented by the general formula (1a), m=1, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: a para position). In the remaining one R.sup.11—O—, in R.sup.11 represented by the general formula (1a), m=2, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: an ortho position and a para position).

##STR00031##

[0399] The compound represented by the formula (1-6) corresponds to a compound in which n=3, and among three R.sup.11—O—'s, two are the same and one is different in the general formula (1). Further, in the same two R.sup.11—O—'s, in R.sup.11 represented by the general formula (1a), m=2, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: an ortho position and a para position). In the remaining one R.sup.11—O—, in RH represented by the general formula (1a), m=1, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: a para position).

##STR00032##

[0400] The compound represented by the formula (1-7) corresponds to a compound in which n=3, and three R.sup.11—O—'s are the same in the general formula (1). Further, in the general formula (1a), m=2, and R.sup.13 is a tert-pentyl group (a position of bonding to a phenyl group: an ortho position and a para position).

[0401] (5) Second phosphite ester (B2)-1

[0402] Distearylpentaerythritol diphosphite (manufactured by JOHOKU CHEMICAL Co., Ltd., JPP-2000PT, a compound represented by the following formula (2-1), phosphorus atom content: 4.2% by mass)

##STR00033##

[0403] The compound represented by the formula (2-1) corresponds to a compound in which R.sup.21 and R.sup.22 are stearyl groups (n-octadecyl groups) in the general formula (2).

[0404] 3. Phosphite ester (B′): Comparative Example compound

[0405] (1) Phosphite ester (a)-1

[0406] Trioleyl phosphite (manufactured by JOHOKU CHEMICAL Co., Ltd., JP-318-O, a compound represented by the following formula (3-1), phosphorus atom content: 3.7% by mass)

[0407] The phosphite ester (B′)-1 is a phosphite ester in which n=0 in the general formula (1), and is a phosphite ester not belonging to the first phosphorus compound (B).

PO—C.sub.18H.sub.37).sub.3   (3-1)

[0408] (2) Phosphite Ester (B′)-2

[0409] Trisnonylphenyl phosphite (manufactured by Sakai Chemical Industry Co., Ltd., TNPP, a compound represented by the following formula (3-2), phosphorus atom content: 4.1% by mass)

[0410] The phosphite ester (B′)-2 is a phosphite ester in which R.sup.13 is a linear alkyl group in the general formula (1a), and is a phosphite ester not belonging to the first phosphorus compound (B).

##STR00034##

[0411] In the formula (3-2), “—nC.sub.9H.sub.19” means a normal nonyl group.

[0412] 4. Second phosphorus compound (C)

[0413] (1) Phosphoric acid compound (C1)

[0414] Tricresyl phosphate (phosphorus atom content: 8.4% by mass)

[0415] (2) Organic phosphine oxide compound (C2)

[0416] Triphenyl phosphine oxide (phosphorus atom content: 10.9% by mass)

[0417] 5. Phosphorus compound belonging to neither first phosphorus compound (B) nor second phosphorus compound (C)

[0418] Tetraphenyl-m-phenylenebisphosphate

[0419] 6. Antioxidant

[0420] Di-tert-butyl-p -cresol (DBPC)

Examples 1 to 29 and Comparative Examples 1 to 12

[0421] Refrigerator oil compositions having compositions noted in Table 1 to Table 4 were prepared, and the wear resistance was evaluated by the Falex wear test described below. The evaluation results are noted in Table 1 to Table 4. In the blending compositions in Table 1 to Table 4, the numerical value unit is “% by mass.” Further, in Table 1 to Table 4, the compound name of the first phosphite ester (B1)-4 is described as “triphenyl phosphite having three phenyl groups, which is substituted with branched alkyl groups.”

[0422] Further, the P atom content derived from the first phosphorus compound (B), the P atom content derived from the phosphite ester (B′), and the P atom content derived from the second phosphorus compound (C), which are noted in Table 1 to Table 4, were calculated from P atom contents of raw materials, respectively.

[0423] <Falex Wear Test>

[0424] The following items were prepared as a pin and a block.

[0425] Pin: SAE-3135

[0426] Block AISI-1137

[0427] The following test was performed by using a Falex tester in accordance with ASTM D2670.

[0428] The pin and the block were set in the Falex tester, 300 g of the refrigerator oil composition as an evaluation target was put into a test container while 30 g of R1234yf was filled as a refrigerant. Then, the test container was sealed. Then, after a rotation speed of 0.09 m/s, an oil temperature of 60° C., and a load of 1,779 N were set, an operation was carried out for 60 min, and then the total wear amount (mg) of the pin and the block was measured.

[0429] This Falex test is a Falex test under harsher conditions than before because the oil temperature and the load are higher than usual.

[0430] The evaluation criteria were as follows. The smaller the wear amount (mg), the better the wear resistance.

[0431] Evaluation S (pass): 2.0 mg or less

[0432] Evaluation A (pass): greater than 2.0 mg and 2.5 mg or less

[0433] Evaluation B (pass): greater than 2.5 mg and less than 5.0 mg

[0434] Evaluation C (failure): 5.0 mg or more

TABLE-US-00001 TABLE 1 Example Unit 1 2 3 4 5 6 Base oil (A) PAG % by 98.5 98.3 98.5 98.3 98.5 98.7 mass PVE % by — — — — — — mass First First phosphite Isodecyldiphenyl phosphite % by 0.3 0.5 — — — — phosphorus ester (B1)-1 mass compound First phosphite 2-ethylhexyldiphenyl % by — — 0.3 0.5 — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — 0.3 — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by — — — — — 0.1 ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — — — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by 0.9 0.9 0.9 0.9 0.9 0.9 phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — — — neither First phosphorus phenylenebis phosphate mass compound (B) nor Second phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived ppm by 242 404 259 431 213 49 of P atom content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived ppm by 756 756 756 756 756 756 P atom content mass Compound corresponding to neither First ppm by 0 0 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 998 1160 1015 1187 969 805 mass Evaluation Wear amount in FALEX wear test mg 4.6 2.7 3.6 2.5 3.2 2.4 result) Evaluation B B B A B A Example Unit 7 8 9 10 11 12 Base oil (A) PAG % by 98.5 98.3 99.1 98.9 98.7 98.5 mass PVE % by — — — — — — mass First First phosphite Isodecyldiphenyl phosphite % by — — — — — — phosphorus ester (B1)-1 mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by 0.3 0.5 0.1 0.3 0.5 — ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — — 0.3 ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — — — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by 0.9 0.9 0.5 0.5 0.5 0.9 phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — — — neither First phosphorus phenylenebis phosphate mass compound (B) nor Second phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 146 244 49 146 244 126 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 756 756 420 420 420 756 content mass Compound corresponding to neither First ppm by 0 0 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 902 1000 469 566 664 882 mass Evaluation Wear amount in FALEX wear test mg 1.3 0.8 2.5 1.9 1.6 2.4 result) Evaluation S S A S S A

TABLE-US-00002 TABLE 2 Example Example Example Example Example Unit 13 14 15 16 17 Base oil (A) PAG % by 98.7 98.5 98.3 98.7 98.7 mass PVE % by — — — — — mass First First phosphite Isodecyldiphenyl % by — — — 1.0 — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — 1.0 (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by 0.1 0.3 0.5 — — ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by — — — — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by 0.9 0.9 0.9 — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 49 146 244 807 862 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 981 981 981 0 0 content mass Compound corresponding to neither First ppm by 0 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 1030 1127 1225 807 862 mass Evaluation Wear amount in FALEX wear test mg 1.1 0.9 0.8 2.8 2.6 result Evaluation S S S B B Example Example Example Example Unit 18 19 20 21 Base oil (A) PAG % by 98.7 99.2 98.7 98.7 mass PVE % by — — — — mass First First phosphite Isodecyldiphenyl % by — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by 1.0 — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by — 0.5 1.0 — ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — 1.0 ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by — — — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 710 244 488 420 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 0 0 0 0 content mass Compound corresponding to neither First ppm by 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 710 244 488 420 mass Evaluation Wear amount in FALEX wear test mg 2.3 4.9 2.4 4.6 result Evaluation A B A B

TABLE-US-00003 TABLE 3 Example Example Example Example Unit 22 23 24 25 Base oil (A) PAG % by- — — — — mass PVE % by- 98.7 98.5 98.3 99.1 mass First First phosphite Isodecyldiphenyl % by- — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2- ethylhexyldiphenyl % by- — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by- — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by- 0.1 0.3 0.5 0.1 ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by- — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by- — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by- — — — — (B)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by- 0.9 0.9 0.9 0.5 phosphorus compound (C1) mass compound Organic Triphenylphosphine % by- — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by- — — — — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by- 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 49 146 244 49 of content mass refrigerator Phosphite ester (B) -derived P atom content ppm by 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 756 756 756 420 content mass Compound corresponding to neither First ppm by 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 805 902 1000 469 mass Evaluation Wear amount in FALEX wear test mg 2.3 2.1 1.2 2.3 result Evaluation A A S A Example Example Example Example Unit 26 27 28 29 Base oil (A) PAG % by- — — — — mass PVE % by- 98.9 98.7 99.2 98.7 mass First First phosphite Isodecyldiphenyl % by- — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2- ethylhexyldiphenyl % by- — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by- — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by- 0.3 0.5 0.5 1.0 ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by- — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by- — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by- — — — — (B)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by- 0.5 0.5 — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by- — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by- — — — — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by- 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 146 244 244 488 of content mass refrigerator Phosphite ester (B) -derived P atom content ppm by 0 0 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 420 420 0 0 content mass Compound corresponding to neither First ppm by 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 566 664 244 488 mass Evaluation Wear amount in FALEX wear test mg 2.0 1.6 4.8 1.7 result Evaluation S S B S

TABLE-US-00004 TABLE 4 Comparative Example Unit 1 2 3 4 5 6 Base oil (A) PAG % by 98.8 99.2 98.8 99.2 98.8 99.2 mass PVE % by — — — — — — mass First First phosphite Isodecyldiphenyl % by — — — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by — — — — — — ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — 0.9 — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — — — 0.5 (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by 0.9 0.5 — — — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — 0.9 0.5 — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — — — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 0 0 0 0 0 0 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 0 0 333 205 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 756 420 981 545 0 0 content mass Compound corresponding to neither First ppm by 0 0 0 0 0 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 756 420 981 545 333 205 mass Evaluation Wear amount in FALEX wear test mg 6.1 8.2 5.2 7.3 14.2 5.6 result) Evaluation C C C C C C Comparative Example Unit 7 8 9 10 11 12 Base oil (A) PAG % by — — — — 99.5 99.2 mass PVE % by 98.8 99.2 98.8 99.2 — — mass First First phosphite Isodecyldiphenyl % by — — — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by — — — — — — ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — 0.9 — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by — — — 0.5 — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by 0.9 0.5 — — — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — — — — 0.2 0.5 neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) -derived P atom ppm by 0 0 0 0 0 0 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 0 0 333 205 0 0 oil mass composition Second phosphorus compound (C) -derived P atom ppm by 756 420 0 0 0 0 content mass Compound corresponding to neither First ppm by 0 0 0 0 210 530 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 756 420 333 205 210 530 mass Evaluation Wear amount in FALEX wear test mg 7.1 13.9 18.7 6.7 7.6 5.1 result) Evaluation C C C C C C

[0435] From Table 1 to Table 4, the followings can be seen.

[0436] It can be found that all the refrigerator oil compositions of Examples 1 to 29 are excellent in the wear resistance.

[0437] In contrast, it can be found that as in Comparative Examples 1, 2, 7, and 8, the refrigerator oil composition in which the first phosphorus compound (B) is not blended, and tricresyl phosphate belonging to the phosphoric acid compound (C1) in the second phosphorus compound (C) is blended is inferior in the wear resistance.

[0438] Further, it can be found that as in Comparative Examples 3 and 4, the refrigerator oil composition in which the first phosphorus compound (B) is not blended, and triphenyl phosphine oxide belonging to the organic phosphine oxide compound (C2) in the second phosphorus compound (C) is blended is inferior in the wear resistance.

[0439] Further, it can be found that as in Comparative Examples 5 and 9, the refrigerator oil composition in which trioleyl phosphite that is a phosphite ester not belonging to the first phosphorus compound (B) is blended is inferior in the wear resistance.

[0440] Further, it can be found that as in Comparative Examples 6 and 10, the refrigerator oil composition in which trisnonylphenyl phosphite that is a phosphite ester not belonging to the first phosphorus compound (B) is blended is inferior in the wear resistance.

[0441] Further, it can be found that as in Comparative Examples 11 and 12, the refrigerator oil composition in which neither the first phosphorus compound (B) nor the second phosphorus compound (C) is blended, and tetraphenyl-m-phenylenebisphosphate that is a compound belonging to neither the first phosphorus compound (B) nor the second phosphorus compound (C) is blended is inferior in the wear resistance.

[0442] <Autoclave Test>

[0443] Fe, Cu, and Al as catalysts were put in an autoclave container (volume: 200 mL), and a mixture of 20 g of each of the refrigerator oil compositions of Example 19 and Comparative Examples 6, 11, and 12 and 20 g of a refrigerant (R1234yf) was filled while 2,000 ppm by mass of water was filled. This was maintained at 175° C. for 336 h, and then, the acid value (mgKOH/g) was evaluated.

[0444] The acid value was measured by the indicator photometric titration method (see Annex 1 in the JIS standard described on the left) in accordance with JIS K2501:2003.

[0445] The evaluation criteria were as follows. The smaller the value of the acid value, the better the thermal stability.

[0446] Evaluation A (pass): 0.5 mgKOH/g or less

[0447] Evaluation B (failure): greater than 0.5 mgKOH/g and 1.0 mgKOH/g or less

[0448] Evaluation C (failure): greater than 1.0 mgKOH/g

[0449] The results of the autoclave test are noted in Table 5.

TABLE-US-00005 TABLE 5 Comparative Comparative Comparative Example Unit Example 6 Example 11 Example 12 19 Base oil (A) PAG % by 99.2 99.5 99.2 99.2 mass PVE % by — — — — mass First First phosphite Isodecyldiphenyl -% by — — — — phosphorus ester (B1)-1 phosphite mass compound First phosphite 2-ethylhexyldiphenyl % by — — — — (B) ester (B1)-2 phosphite mass First phosphite Phenyldiisodecyl phosphite % by — — — — ester (B1)-3 mass First phosphite Triphenyl phosphite having % by — — — 0.5 ester (B1)-4 three phenyl groups, which mass is substituted with branched alkyl groups Second phosphite Distearyl pentaerythritol % by — — — — ester (B2)-1 diphosphite mass Phosphite Phosphite ester Trioleyl phosphite % by — — — — ester (B′)-1 mass (B′) Phosphite ester Trisnonylphenyl % by 0.5 — — — (B′)-2 phosphite mass Second Phosphoric acid Tricresyl phosphate % by — — — — phosphorus compound (C1) mass compound Organic Triphenylphosphine % by — — — — (C) phosphineoxide oxide mass compound (C2) Compound corresponding to Tetraphenyl-m- % by — 0.2 0.5 — neither First phosphorus phenylenebis mass compound (B) nor Second phosphate phosphorus compound (C) Antioxidant DBPC % by 0.3 0.3 0.3 0.3 mass Properties First phosphorus compound (B) - derived P atom ppm by 0 0 0 244 of content mass refrigerator Phosphite ester (B′) -derived P atom content ppm by 205 0 0 0 oil mass composition Second phosphorus compound (C) - derived P atom ppm by 0 0 0 0 content mass Compound corresponding to neither First ppm by 0 210 530 0 phosphorus compound (B) nor Second mass phosphorus compound (C) -derived P atom content Total content of P atoms ppm by 205 210 530 244 mass Evaluation Acid value after autoclave test mgKOH/g 0.65 0.67 1.23 0.34 result Evaluation — B B C A

[0450] From the results noted in Table 5, the followings can be seen.

[0451] It can be seen that the refrigerator oil composition illustrated in Example 19 is excellent in the thermal stability.

[0452] In contrast, it can be seen that the thermal stability is inferior when trisnonylphenyl phosphite that is a phosphite ester not corresponding to the first phosphorus compound (B) is used as in Comparative Example 6, or tetraphenyl-m-phenylenebisphosphate that is a compound corresponding to neither the first phosphorus compound (B) nor the second phosphorus compound (C) is used as in Comparative Examples 11 and 12.