US-12624306-B2 - Refrigerator oil composition and mixed composition for refrigerator

Abstract

A refrigerator oil composition may effectively suppress an increase in an acid value even when a ratio of an unsaturated fluorinated hydrocarbon compound (HFO) in a refrigerant is increased. Such a refrigerator oil composition can used for a refrigerant and may include one or more unsaturated fluorinated hydrocarbon compounds of formula (1): C x F y H  (1), wherein x is an integer of 2 to 6, y is an integer of 1 to 11, and z is an integer of 1 to 11, and one or more carbon-carbon unsaturated bonds are present in the molecule. The refrigerator oil composition may include a base oil (A), and one or more silicone compounds (B) selected from the group consisting of an unmodified silicone (B1) and a modified silicone (B2), wherein a content of the silicone compound (B) is 0.05% by mass or more based on the total amount of the refrigerator oil composition.

Inventors

• So NAKAJIMA

Assignees

• IDEMITSU KOSAN CO., LTD.

Dates

Publication Date

20260512

Application Date

20220315

Priority Date

20210316

Claims (8)

1. 1 . A refrigerator oil composition, comprising: a base oil; and a modified silicone compound comprising a side-chain modified silicone in which at least a side chain of a polysiloxane skeleton is modified to have one or more epoxy groups, wherein the base oil comprises polyvinyl ether compounds, a content of the base oil is from 92% to 98% by mass based on the total amount of the refrigerator oil composition, a content of the modified silicone compound is 0.5% by mass or more based on the total amount of the refrigerator oil composition, and the refrigerator oil composition is capable to be mixed with a refrigerant comprising one or more unsaturated fluorinated hydrocarbon compounds selected from the group consisting of R1234ze, R1234yf, and R1234ye.
2. 2 . The refrigerator oil composition of claim 1 , further comprising an acid scavenger.
3. 3 . The refrigerator oil composition according to claim 2 , wherein a content ratio of the modified silicone compound to the acid scavenger is 0.025 or more in terms of mass ratio.
4. 4 . The refrigerator oil composition of claim 1 , further comprising an oxidation inhibitor.
5. 5 . The refrigerator oil composition according to claim 4 , wherein a content ratio of the modified silicone compound to the oxidation inhibitor is 0.17 or more in terms of mass ratio.
6. 6 . A mixed composition for a refrigerator comprising: a refrigerant comprising at least one compound selected from the group consisting of R1234ze, R1234yf, and R1234ye; and the refrigerator oil composition of claim 1 .
7. 7 . A method for producing the refrigerator oil composition according to claim 1 , comprising: mixing the base oil and the modified silicone compound comprising a side-chain modified silicone in which at least a side chain of a polysiloxane skeleton is modified to have one or more epoxy groups, wherein a blending amount of the modified silicone compound is 0.5% by mass or more based on the total amount of the refrigerator oil composition.
8. 8 . The refrigerator oil composition of claim 1 , wherein the content of the modified silicone compound is 1.0% by mass or more based on the total amount of the refrigerator oil composition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is the national stage of international application PCT/JP2022/011608, filed on Mar. 15, 2022, and claims the benefit of the filing date of Japanese Appl. No. 2021-042722, filed on Mar. 16, 2021. TECHNICAL FIELD The present invention relates to a refrigerator oil composition, and a mixed composition for a refrigerator. In the description herein, the term “mixed composition for a refrigerator” refers to a composition obtained by mixing the “refrigerator oil composition” and a “refrigerant”. BACKGROUND ART Refrigerators, for example, compression-type refrigerators generally include at least compressors, condensers, expansion mechanisms (for example, expansion valves and the like), and evaporators, and have a structure in which a mixed composition for a refrigerator circulates in a closed system. As a refrigerant used in a refrigerator such as a compression-type refrigerator, a fluorinated hydrocarbon compound having a low environmental load is being used instead of a hydrochlorofluorocarbon (HCFC) which has been conventionally used in many cases. As the fluorinated hydrocarbon compounds, saturated fluorinated hydrocarbon compounds (Hydro-Fluoro-Carbon; hereinafter also referred to as “HFC”) such as 1,1,1,2-tetrafluoroethane (R134a), difluoromethane (R32), and 1,1-difluoroethane (R152a) are being used. In addition, the use of unsaturated fluorinated hydrocarbon compounds (Hydro-Fluoro-Olefin; hereinafter also referred to as “HFO”) such as 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf, and 1,2,3,3-tetrafluoropropene (R1234ye) having low global warming potential (GWP) has also been examined (see, for example, PTL 1). CITATION LIST Patent Literature PTL 1: JP 2006-503961 SUMMARY OF INVENTION Technical Problem However, while unsaturated fluorinated hydrocarbon compounds (HFO) have an advantage of a low global warming potential (GWP), they have a disadvantage of inferior thermal stability at high temperatures compared to saturated fluorinated hydrocarbon compounds (HFC). Therefore, when a content of the unsaturated fluorinated hydrocarbon compound (HFO) in the refrigerant increases, there is a problem that an acid value of the refrigerator oil composition is likely to increase. In addition, in recent years, refrigerators have been made more compact and higher in performance, and their operating conditions have become severer than before. Therefore, the refrigerator oil composition is required to have higher quality than ever before. For example, while the amount of refrigerator oil composition used in the equipment is decreasing along with the compactification of the refrigerator, a portion which is locally high in temperature is likely to be generated due to frictional heat and the like in a sliding portion of the compressor due to the severe operating conditions. When the mixed composition for a refrigerator is exposed to such a portion, the acid value of the refrigerator oil composition is more likely to increase. Therefore, it is desired to create a refrigerator oil composition that can effectively suppress an increase in the acid value even when the content of the unsaturated fluorinated hydrocarbon compound (HFO) in the refrigerant is increased. The present invention has been made in view of such a demand, and an object of the present invention is to provide a refrigerator oil composition capable of effectively suppressing an increase in an acid value even when a content of an unsaturated fluorinated hydrocarbon compound (HFO) in a refrigerant is increased, and a mixed composition for a refrigerator containing the refrigerator oil composition. Solution to Problem The present inventor has conducted intensive studies to solve the above problem. As a result, the present inventor has found that a refrigerator oil composition containing a specific amount or more of one or more silicone compounds (B) selected from the group consisting of an unmodified silicone (B1) and a modified silicone (B2) can solve the problem, and has completed the present invention. That is, the present invention relates to the following [1] to [3]. [1] A refrigerator oil composition used for a refrigerant containing one or more unsaturated fluorinated hydrocarbon compounds selected from compounds represented by the following general formula (1): CxFyHz  (1) wherein x is an integer of 2 to 6, y is an integer of 1 to 11, and z is an integer of 1 to 11, and one or more carbon-carbon unsaturated bonds are present in the molecule, the refrigerator oil composition containing: a base oil (A); and one or more silicone compounds (B) selected from the group consisting of an unmodified silicone (B1) and a modified silicone (B2), wherein a content of the silicone compound (B) is 0.05% by mass or more based on the total amount of the refrigerator oil composition. [2] A mixed composition for a refrigerator containing: a refrigerant containing at least one compoun