Thiodicarboxylic Acid Ester Storage Stability
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Solution Overview
Problem
Thiodicarboxylic acid esters, which possess antioxidant and wear-resistant properties, suffer from poor storage stability and increased acid value over time, making them unsuitable for long-term use in lubricating oil compositions.
Innovation Solution
A compound (B) is used in combination with a thiodicarboxylic acid ester-based lubricating oil additive composition to adjust the acid value within a specific range (0.01 to 0.4 mgKOH/g), enhancing storage stability without compromising antioxidant and wear-resistant properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thiodicarboxylic acid esters are used as lubricating oil additives to provide antioxidant and wear-resistant properties, then the lubricating oil exhibits multiple effects with reduced additive amounts, but the storage stability deteriorates and acid value increases over time
Solution Approach 1:
The patent introduces a specific additive composition containing thiodicarboxylic acid ester derivatives in combination with other additives (such as zinc dialkyldithiophosphate and phenolic antioxidants) as an intermediary system. This composite additive package mediates between the need for multiple functions and storage stability, where the synergistic interaction of components prevents acid value increase while maintaining antioxidant and wear-resistant properties.
Solution Approach 2:
The patent employs composite additive materials by combining thiodicarboxylic acid ester derivatives with other lubricant additives in specific ratios. This composite approach creates a synergistic effect where the combination provides both antioxidant and wear-resistant properties while the stabilizing components prevent degradation during storage, thus resolving the contradiction between versatility and stability.
2Ease of manufacture
If thiodicarboxylic acid esters are used to reduce the amount of other additives needed, then cost is reduced and fewer additive interactions occur, but storage stability deteriorates and acid value increases
Solution Approach 1:
The patent modifies the chemical parameters of the thiodicarboxylic acid ester by using specific derivatives with controlled chain lengths and structural variations. These parameter changes optimize the balance between functionality and stability, allowing cost-effective single-additive solutions while preventing the acid value increase that plagues conventional thiodicarboxylic acid esters during storage.
3Adaptability or versatility
If the acid value of thiodicarboxylic acid esters is allowed to increase over time, then the additive structure changes, but the performance of lubricating oil composition becomes unstable and unpredictable
Solution Approach 1:
The patent extracts and addresses the specific problem of acid value increase by introducing stabilizing additives that specifically counteract the degradation mechanism of thiodicarboxylic acid esters. This targeted approach removes the harmful acid value increase while preserving the beneficial antioxidant and wear-resistant properties, ensuring consistent performance.
Data Source
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AI summary
The purpose of the present invention is to provide a thiodicarboxylic acid ester which has high long-term storage stability without inhibiting antioxidant properties and wear-resistant properties of the thiodicarboxylic acid ester. In order to achieve the above-mentioned purpose, the present invention provides a lubricating oil additive composition which is characterized by containing a compound (A) represented by general formula (1) and a compound (B) represented by general formula (2) and by having an acid value of 0.01-0.4 mgKOH/g. (in the formula, R1 and R4 each independently represent a hydrocarbon group having 6 to 18 carbon atoms and R2 and R3 each independently represent an alkylene group having 1 to 4 carbon atoms) (in the formula, R5 represents a hydrocarbon group having 6 to 18 carbon atoms and R6 and R7 each independently represent an alkylene group having 1 to 4 carbon atoms).