Polyol Ester Refrigerant Oil for Unsaturated HFO Lubricity
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Solution Overview
Problem
Refrigerating machine oils exhibit unpredictable behaviors when used with unsaturated hydrofluorocarbon refrigerants, lacking superior lubricity and antiwear properties compared to those used with saturated hydrofluorocarbons.
Innovation Solution
A refrigerating machine oil composition comprising an ester of a polyhydric alcohol and a fatty acid, combined with an ether compound of a polyhydric alcohol, specifically designed for use with unsaturated hydrofluorocarbon refrigerants, such as 1,3,3,3-tetrafluoropropene and 2,3,3,4-tetrafluoropropene, to enhance lubricity and antiwear properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a refrigerating machine oil is designed for use with saturated hydrofluorocarbon refrigerants, then it exhibits superior thermal and chemical stability and lubricity, but it does not necessarily show superior properties for use with unsaturated hydrofluorocarbon refrigerants
Solution Approach 1:
The invention changes the chemical composition parameters of the base oil from conventional mineral oils or simple esters to polyol esters with specific molecular structures (polyhydric alcohols with 3-6 hydroxyl groups). This parameter change enables the oil to achieve both thermal stability and adaptability to unsaturated hydrofluorocarbon refrigerants, resolving the contradiction between reliability and versatility.
Solution Approach 2:
The invention creates a composite lubricating oil system by combining polyol esters with specific additives including ether compounds, esters, and other auxiliary additives. This composite formulation achieves synergistic effects that provide both the thermal/chemical stability required for saturated HFCs and the lubricity needed for unsaturated HFOs, simultaneously addressing both requirements.
2Ease of manufacture
If conventional base oils are used with unsaturated hydrofluorocarbon refrigerants, then the system is simpler to manufacture, but the lubricity and antiwear properties become unpredictable and inferior
Solution Approach 1:
The invention specifies precise compositional parameters for polyol esters, including the type of polyhydric alcohol (3-6 hydroxyl groups), fatty acid chain lengths (C4-C20), and additive concentrations (ether compound: 0.01-5 mass%, ester: 1-20 mass%). These controlled parameters ensure consistent lubricity and antiwear properties while maintaining manufacturability through established chemical synthesis methods.
3Reliability
If the content of ether compound is increased to improve lubricity, then antiwear property improves, but excessive content may adversely affect other properties
Solution Approach 1:
The invention applies partial action by limiting the ether compound content to a specific range (0.01-5 mass%, preferably 0.1-2 mass%). This partial addition provides sufficient antiwear protection without excessive content that could cause adverse effects, achieving the optimal balance between lubricity improvement and overall composition stability.
Solution Approach 2:
The invention precisely controls the concentration parameter of ether compounds within a narrow optimal range, transforming the quality of lubricity and antiwear protection while maintaining overall oil stability. This parameter optimization resolves the contradiction between improving antiwear properties and maintaining composition stability.
Data Source
AI summary
The present invention provides a refrigerating machine oil comprising: an ester of a polyhydric alcohol and a fatty acid as a base oil; and an ether compound of a polyhydric alcohol, the refrigerating machine oil being used with an unsaturated hydrofluorocarbon refrigerant.