Ester Base Oil Molecular Weight Distribution for Refrigerant Compatibility

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Solution Overview

Problem

Refrigerating machine oils need to balance low temperature properties and flame retardancy, especially when using mildly flammable hydrofluorocarbon refrigerants, as existing solutions do not consistently achieve both requirements effectively.

Innovation Solution

An ester base oil is developed from pentaerythritol and mixed fatty acids with specific carbon lengths, with a controlled molecular weight distribution ratio (Mw/Mn) between 1.06 and 1.20, ensuring compatibility with both low temperature performance and flame retardancy, and used in conjunction with a mildly flammable hydrofluorocarbon refrigerant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an ester base oil with narrow molecular weight distribution is used to control low temperature properties, then low temperature property is improved, but flame retardancy cannot be sufficiently achieved

Engineering Contradiction:

Improvelow temperature propertyVSAvoidflame retardancy

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the molecular weight distribution parameters of the ester base oil by controlling the ratio of weight average molecular weight to number average molecular weight (Mw/Mn) to be within 1.05 to 1.15. This parameter optimization allows the oil to achieve both low temperature fluidity and flame retardancy with mildly flammable refrigerants like HFO-1234ze and HFO-1234yf.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite ester base oil formed by mixing esters with different molecular weights and structures. The specific composition includes esters represented by formulas (1) and (2) with controlled molecular weight distribution, creating a composite material that balances low temperature properties and flame retardancy.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If various esters with different structures are present in the ester base oil, then manufacturing flexibility is improved, but property control becomes difficult

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidproperty control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent establishes specific parameter ranges for the ester base oil composition, including the Mw/Mn ratio (1.05-1.15) and specific ester content ratios. These parameter specifications enable consistent property control while allowing manufacturing flexibility within the defined ranges.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent specifies different ester components with particular structures and proportions, where each ester type contributes specific properties. The controlled distribution of different ester structures (formulas 1 and 2) allows optimization of both low temperature fluidity and flame retardancy through localized compositional control.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3216850B1Refrigerator oil and working fluid composition for refrigerator

Publication Date: 2022.03.02 ENEOS CORP

Figure 1

AI summary

The present invention provides a refrigerating machine oil containing an ester base oil obtained from pentaerythritol and mixed fatty acids of a fatty acid having 8 carbon atoms and a fatty acid having 9 carbon atoms, wherein a ratio of a weight average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, of the ester base oil is 1.06 to 1.20, and used with a mildly flammable hydrofluorocarbon refrigerant.