Hybrid Grease Composition for High Dropping Point at Lower Cost
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Solution Overview
Problem
Existing greases, such as hydrated calcium soaps and conventional lithium greases, have low heat resistance, limiting their use to temperatures below 200°C, while overbased metal detergent greases are costly, making them unsuitable for widespread adoption.
Innovation Solution
A hybrid grease formulation combining metal carboxylate soaps and overbased metal detergents, including overbased metal sulfonates, salicylates, naphthenates, or oleate detergents, with a total base number (TBN) of 150 to 500 mg KOH/g equivalents, and a dropping point exceeding 220°C, achieved by mixing an oil of lubricating viscosity, overbased metal detergent, metal carboxylate soap, and oxygenate promoters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If overbased metal detergent greases are used, then temperature stability and dropping point are improved (above 300°C), but cost increases significantly (50% premium over lithium greases)
Solution Approach 1:
The patent combines overbased metal detergent (5-22.5 wt%) with anhydrous metal soap (5-18.5 wt%) to create a hybrid grease system that merges the high temperature stability of overbased detergents with the cost-effectiveness of anhydrous soaps, achieving dropping points above 220°C at lower cost than pure overbased detergent greases
Solution Approach 2:
The invention creates a composite grease formulation using multiple thickener systems (overbased metal detergent and anhydrous metal soap) alongside base oils and additives, producing a material with integrated properties that balance performance and cost, specifically achieving high dropping point without the full premium of pure overbased detergent formulations
2Temperature
If conventional lithium greases are used, then dropping point is improved (around 200°C), but cost increases due to lithium hydroxide price increases
Solution Approach 1:
The patent replaces expensive lithium-based thickeners with more economical alternatives consisting of anhydrous metal soaps (particularly calcium soaps) combined with overbased metal detergents, achieving comparable high-temperature performance without dependency on volatile lithium hydroxide prices
Solution Approach 2:
The invention changes the chemical composition parameters of the grease by using overbased metal detergents with TBN of 150-500 mg KOH/g and specific ratios of thickener components, transforming the base formulation from lithium-based to a hybrid system that maintains dropping points above 220°C while reducing cost
3Ease of manufacture
If anhydrous calcium soaps are used, then cost is reduced and ease of use is improved, but dropping point is limited (150-160°C)
Solution Approach 1:
The patent merges anhydrous metal soap (提供成本优势) with overbased metal detergent (提供高温稳定性) to create a synergistic hybrid system where the combination achieves dropping points above 220°C, surpassing the performance of either component alone while maintaining cost effectiveness
Data Source
AI summary
Greases that are suitable for use in high temperature applications and are cost-effective alternatives to lithium greases. The greases are prepared from an oil of lubricating viscosity; 1.0 to 22.5 wt % of an overbased metal detergent; 5.0 to 18.5 wt % of a metal carboxylate soap component that is the reaction product of a metal hydroxide and/or metal carbonate with a fatty acid; 0.2 to 8.0 wt % of an oxygenate promoter (for example alcohols and/or organic acids); and 1 to 15 wt % of water. The greases have dropping points of at least 220° C., as measured using ASTM D2265.