Polyester Lubricant Sealing Material Expansion

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Solution Overview

Problem

Commercially available lubricant compositions using Group II and Group III hydrorefined paraffinic mineral oils and GTL synthetic oils cause shrinkage in sealing materials, and there is a need for lubricants with high viscosity index and improved low-temperature characteristics to enhance energy efficiency and sealing material expansion.

Innovation Solution

A polyester is synthesized by reacting adipic acid with a mixture of 1-nonanol, monomethyloctanols, and dimethylheptanols, which has a viscosity range of 5 to 15 mm^2/s at 40°C, density of 0.85 to 1.00 g/cm^3, and refractive index of 1.400 to 1.500, providing improved sealing material expansion and low-temperature behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Group II and Group III hydrorefined paraffinic mineral oils or GTL synthetic oils are used as base oils, then good lubrication performance is achieved, but sealing materials shrink

Engineering Contradiction:
Improvelubrication performanceVSAvoidsealing material shrinkage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces polyesters as an intermediary substance that mediates between the base oil and sealing materials. The polyesters interact with the sealing materials to prevent shrinkage caused by the base oil, while maintaining the lubrication performance. This is achieved by selecting specific polyester molecular weights and compositions that can simultaneously satisfy lubrication requirements and seal compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the lubricant by incorporating polyesters with specific molecular weights (1,000 to 10,000 g/mol) and structures. By adjusting the polyester content (0.1-50 wt%) and molecular weight distribution, the patent optimizes both the lubrication performance and seal material compatibility, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If polyesters with high viscosity index are used, then energy efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent achieves high viscosity index (above 140) by carefully controlling the polyester molecular weight (1,000 to 10,000 g/mol) and composition parameters. This parameter optimization allows the use of commercially available polyester synthesis processes, avoiding excessive manufacturing complexity while achieving the desired energy efficiency through reduced power consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses commercially available polyesters with defined properties rather than requiring complex custom synthesis processes. This approach leverages existing industrial capabilities to produce cost-effective lubricant compositions that achieve high viscosity index without excessive manufacturing complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If polyesters are added to expand sealing materials, then seal compatibility improves, but viscosity control becomes more difficult

Engineering Contradiction:
Improveseal expansionVSAvoidviscosity stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent maintains viscosity stability by optimizing the polyester molecular weight range (1,000 to 10,000 g/mol) and content (0.1-50 wt%). These parameter constraints ensure that the polyester adds sufficient expansion to improve seal compatibility while maintaining the overall viscosity within acceptable ranges for lubrication performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite lubricant system combining base oils with specific polyesters. This composite approach allows the polyester component to provide seal expansion benefits while the base oil maintains viscosity stability, achieving both objectives through synergistic material combination.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The synthesized polyester effectively expands sealing materials and exhibits improved low-temperature characteristics, achieving a viscosity index above 140 and suitable viscosity, density, and refractive index, thus addressing the energy efficiency and sealing material expansion issues.

Implementation Method 1

polyester obtainable by reacting a mixture comprising adipic acid and an alcohol mixture comprising 1-nonanol, monomethyloctanols, dimethylheptanols and monoethylheptanols

Methodology Applied
Scientific EffectEsterification: Chemical Bonding

Data Source

PatentEP2920281B1Use of polyesters as lubricants
Publication Date: 2019.05.08 BASF SE

AI summary

The presently claimed invention is directed to the novel use of polyester obtainable by reacting a mixture comprising adipic acid and an alcohol mixture comprising 1-nonanol, monomethyloctanols, dimethylheptanols and monoethylheptanols as lubricants and a lubricant composition comprising these polyesters.