Polyoxyalkylene Grease with Solid Lubricants for Spalling Protection
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Solution Overview
Problem
Existing grease compositions containing polyoxyalkylene or polyoxyalkylene derivatives as base oils face challenges in maintaining spalling preventive properties and thermal stability under high temperature and high surface pressure conditions, particularly when using reactive anti-spalling additives, which accelerate decomposition, and non-reactive additives provide insufficient protection.
Innovation Solution
A grease composition combining polyoxyalkylene or ether derivatives of polyoxyalkylene as base oils with polytetrafluoroethylene as a first solid lubricant and calcium carbonate, calcium oxide, or tricalcium phosphate as a second solid lubricant, with a minimum content of 0.5% each, enhances spalling prevention and thermal stability without reactive additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reactive anti-spalling additive is used in grease containing polyoxyalkylene as base oil, then spalling preventive properties are improved, but thermal stability deteriorates due to accelerated decomposition of polyoxyalkylene at high temperature
Solution Approach 1:
The patent removes the reactive anti-spalling additive from the grease composition, extracting the harmful element that causes thermal decomposition while retaining the beneficial polyoxyalkylene base oil. This extraction resolves the contradiction by eliminating the source of thermal instability while maintaining spalling prevention through alternative non-reactive solid lubricant additives.
Solution Approach 2:
The patent introduces a non-reactive solid lubricant additive as an intermediary substance that provides spalling prevention without triggering the harmful chemical reactions. This intermediary approach allows the system to achieve the desired protective function while avoiding the thermal decomposition issue associated with reactive additives.
2Stability of the object's composition
If a non-reactive anti-spalling additive is used instead of reactive additive, then thermal stability is improved, but spalling preventive properties deteriorate due to insufficient protection under high temperature and high surface pressure
Solution Approach 1:
The patent combines multiple non-reactive solid lubricant additives (such as PTFE, MoS2, WS2, or B4C) within the grease composition to create a synergistic effect. This combination provides enhanced spalling prevention capabilities while maintaining thermal stability, as each additive contributes different protective mechanisms that work together without causing harmful reactions.
Solution Approach 2:
The patent creates a composite grease system by combining polyoxyalkylene base oil with non-reactive solid lubricant additives. This composite material approach allows the system to integrate the thermal stability of the base oil with the spalling protection of the solid lubricants, achieving both objectives simultaneously through material composition rather than chemical reaction.
3Adaptability or versatility
If polyoxyalkylene or polyoxyalkylene derivative is used as base oil, then compatibility with rubber sealing members is improved, but spalling preventive properties deteriorate under high temperature due to accelerated decomposition
Solution Approach 1:
The patent extracts the problematic reactive additive component that causes decomposition of polyoxyalkylene at high temperature. By removing this harmful element while retaining the polyoxyalkylene base oil, the system maintains its excellent compatibility with rubber sealing members while eliminating the thermal decomposition issue that compromised spalling prevention.
Solution Approach 2:
The patent changes the chemical parameters of the additive system by switching from reactive to non-reactive solid lubricants. This parameter change allows the grease to operate effectively at high temperatures without accelerating polyoxyalkylene decomposition, thereby maintaining both rubber compatibility and spalling prevention capabilities.
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 composition improves spalling preventive properties and heat resistance, preventing base oil decomposition even under harsh conditions, while maintaining compatibility with rubber seals.
Implementation Method 1
The non-reactive anti-spalling additive works by adhering to metal surfaces and preventing metal-to-metal contact
Implementation Method 2
The reactive anti-spalling additive works by causing a reaction on a metal surface and forming a protective film thereon
Implementation Method 3
grease to be used in lubrication sites of these mechanical parts
Data Source
AI summary
A grease composition includes a base oil, a thickener, and an additive. The base oil is at least one selected from the group consisting of polyoxyalkylene, ether derivatives of polyoxyalkylene, and mixtures thereof. The additive includes polytetrafluoroethylene as a first solid lubricant and at least one selected from the group consisting of calcium carbonate, calcium oxide, tricalcium phosphate, and calcium salts of fatty acids as a second solid lubricant. The content of the second solid lubricant is 0.5% by mass or more based on the total mass of the composition.