Lithium-Containing Calcium Complex Grease Thermal Stability
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Solution Overview
Problem
Current grease compositions using lithium soap or urea as thickeners face challenges with resource depletion, high production costs, safety concerns, and inadequate thermal resistance and shear stability, which are not met by calcium soap-based greases under harsh operating conditions.
Innovation Solution
A grease composition using a lithium-containing calcium complex soap thickener, comprising specific higher and lower fatty acids and aromatic monocarboxylic acids, which provides a high dropping point, excellent shear stability, and long bearing life, while being environmentally friendly and cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium soap or urea is used as a thickener to achieve high dropping point and thermal resistance, then thermal stability is improved, but resource depletion, high production cost, and safety concerns arise
Solution Approach 1:
The patent changes the chemical composition parameters by using calcium hydroxide and lithium hydroxide in a specific molar ratio (Ca:Li = 4:1 to 1:1) to create a lithium-containing calcium complex soap thickener. This parameter change maintains high dropping point (above 200°C) and thermal stability while using more abundant and safer materials compared to traditional lithium soap or urea-based greases
Solution Approach 2:
The patent creates a composite thickener system combining calcium hydroxide and lithium hydroxide in a specific molar ratio to form lithium-containing calcium complex soap. This composite material approach leverages the high dropping point contribution from calcium components while incorporating lithium to enhance thermal stability, achieving performance comparable to lithium soap grease but with improved safety and resource sustainability
2Object-affected harmful factors
If calcium soap is used as a thickener to improve safety and reduce cost, then safety and environmental benefits are achieved, but dropping point and thermal resistance deteriorate
Solution Approach 1:
The patent modifies the calcium soap system by adding lithium hydroxide in a controlled molar ratio (Ca:Li = 4:1 to 1:1), which changes the thermal properties of the thickener. This parameter adjustment raises the dropping point above 200°C and improves thermal resistance while maintaining the safety and environmental benefits of calcium-based materials
Solution Approach 2:
The patent creates a composite thickener system combining calcium hydroxide and lithium hydroxide to form lithium-containing calcium complex soap. This composite approach integrates the safety and environmental advantages of calcium soap with the thermal stability benefits of lithium components, achieving a balanced performance profile
3Reliability
If existing calcium complex grease formulations are used to achieve high dropping point, then thermal resistance is improved, but consistency cannot be maintained with small thickener amounts and production requires high temperature
Solution Approach 1:
The patent optimizes the molar ratio of calcium hydroxide to lithium hydroxide (Ca:Li = 4:1 to 1:1) and controls the thickener content (1-20 parts by mass per 100 parts base oil) to achieve high dropping point above 200°C while maintaining suitable grease consistency. This parameter optimization eliminates the need for high-temperature terephthalic acid introduction and enables consistent formulation with moderate thickener amounts
Data Source
AI summary
A grease composition comprising base oil and as thickener calcium complex soap and lithium soap is disclosed. A higher fatty acid, an aromatic monocarboxylic acid and a lower fatty acid are used as carboxylic acids constituting the calcium complex soap and lithium soap. The grease composition has a high dropping point and excellent shear stability, and exhibits thermal stability and long bearing life.