Ashless Phosphorus Antiwear Additive for Copper Corrosion
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Solution Overview
Problem
Conventional lubricating compositions, such as those using zinc dialkyl dithiophosphates, face challenges with copper corrosion, particularly with ashless antiwear additives that provide good antiwear and extreme pressure performance but tend to corrode copper and bronze metals.
Innovation Solution
A lubricating composition is developed with an oil-soluble phosphorus antiwear additive prepared by reacting an organic hydroxy compound with phosphorus pentasulfide, distilling the reaction product to isolate a condensate of dialkyl dithiophosphoric acid, and further reacting it with an unsaturated ester of a carboxylic acid, which is then used in combination with base oils to form a lubricating composition that effectively addresses copper corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ashless dithiophosphates are used as antiwear additives, then antiwear and extreme pressure performance are improved, but copper corrosion increases
Solution Approach 1:
The patent uses an intermediary substance (a specific organic compound with formula (R1R2N-CR3R4)2C=O where R1-R4 are hydrogen or alkyl groups) as a mediator between the ashless dithiophosphate additive and the copper metal. This intermediary compound, present at 0.01-5 wt% of the lubricant composition, modifies the interaction mechanism to prevent direct corrosive attack on copper while maintaining the antiwear benefits of the dithiophosphate additive.
Solution Approach 2:
The patent changes the chemical composition parameters of the lubricant by introducing a specific organic compound with controlled concentration (0.01-5 wt%). This parameter change transforms the chemical environment in the lubricant system, reducing the corrosivity toward copper while preserving the antiwear properties. The specific structural parameters of the added compound (alkyl group sizes and configurations) are optimized to achieve the desired effect.
2Strength
If zinc dialkyl dithiophosphates are used, then antiwear performance is achieved, but zinc content increases which is less desired in some applications
Solution Approach 1:
The patent extracts or removes the zinc element from the dithiophosphate additive structure, transitioning from zinc dialkyl dithiophosphates to ashless (metal-free) dithiophosphates. This extraction eliminates the unwanted zinc content while retaining the core antiwear functionality of the dithiophosphate molecule. The ashless variant achieves comparable antiwear performance without the zinc byproduct issues.
Solution Approach 2:
The patent replaces the expensive and problematic zinc-containing additive with a cheaper, metal-free alternative. The ashless dithiophosphate provides equivalent or superior performance without the drawbacks of zinc ash formation, effectively substituting a less desirable substance with a more suitable one that meets modern environmental and performance requirements.
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 resulting lubricating composition exhibits excellent antiwear performance and significantly reduced copper corrosion, as measured by ASTM standards, demonstrating improved protection for metal components in extreme pressure situations.
Implementation Method 1
reacting an organic hydroxy compound with phosphorus pentasulfide to form a reaction product
Implementation Method 2
distilling the reaction product and recovering a condensate
Implementation Method 3
reacting the condensate with an unsaturated ester of a carboxylic acid to form the oil-soluble phosphorus antiwear additive
Data Source
Figure 1
Figure 2~5
AI summary
An oil-soluble phosphorus antiwear additive and a lubricating composition including the ashless antiwear additive having improved copper corrosion performance obtained by reacting an organic hydroxy compound with phosphorus pentasulfide to form a reaction product, distilling the reaction product and recovering a condensate, and reacting the condensate with an unsaturated ester of a carboxylic acid to form an oil-soluble phosphorus antiwear additive.