Lubricant Composition Friction Modifiers Caterpillar TO-4
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Solution Overview
Problem
Caterpillar TO-4 compliant lubricant compositions face challenges in meeting dynamic and static friction property requirements due to conflicts between scuffing load capacity, copper corrosion performance, and bearing pitting performance, particularly with crankcase lubricants containing friction modifiers like molybdenum and glycerol monooleate.
Innovation Solution
A lubricant composition comprising a base oil, an ashless component P(═S)(SR1)(OR2)(OR3), and a metal dialkyl dithio phosphate salt, with specific phosphorus content and ratios, along with optional additives such as thiadiazole derivatives and overbased metal sulfonates, to enhance scuffing load capacity, copper corrosion resistance, and bearing pitting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If friction modifiers like molybdenum and glycerol monooleate are added to crankcase lubricant compositions, then dynamic and static friction properties are reduced, but the lubricant fails to meet Caterpillar TO-4 specification requirements
Solution Approach 1:
The patent removes traditional friction modifiers (molybdenum compounds and glycerol monooleate) from the lubricant composition that were causing friction properties to be too low. Instead, it uses a specialized friction modifier package with specific compounds (including organic friction modifiers and extreme pressure additives) that increase dynamic and static friction to meet TO-4 specifications while maintaining protective functions.
Solution Approach 2:
The patent changes the chemical composition parameters by introducing specific friction modifier compounds with controlled concentrations. The friction modifier package includes compounds like glycerol monostearate, glycerol monolaurate, and sulfurized polyisobutylene at specific weight percentages (0.01-5.0% total friction modifiers) to achieve the required dynamic friction coefficient of 0.06-0.15 and static friction coefficient of 0.10-0.20.
2Reliability
If additives are selected to improve scuffing load capacity, copper corrosion performance and bearing pitting performance, then performance thresholds improve, but it becomes difficult to meet all Caterpillar TO-4 requirements simultaneously
Solution Approach 1:
The patent employs multifunctional additives that simultaneously address multiple performance requirements. The friction modifier package includes compounds that provide both extreme pressure protection (for scuffing load capacity) and friction modification properties. The use of sulfurized polyisobutylene and metal dialkyl dithio phosphate salts provides combined protection against wear, corrosion, and pitting while maintaining friction within specification limits.
Solution Approach 2:
The patent creates a composite additive system combining multiple types of compounds: organic friction modifiers (glycerol esters), extreme pressure additives (sulfurized polyisobutylene, metal dialkyl dithio phosphate salts), and anti-wear agents. This composite approach allows the lubricant to meet multiple TO-4 specification requirements simultaneously through synergistic interactions between different additive components.
Data Source
AI summary
A lubricant composition and a method of lubricating off-road vehicles and/or machinery. The lubricant composition includes (i) a base oil, (ii) at least one ashless component (A) having the structure P(═S)(SR1)(OR2)(OR3), wherein R1, R2 and R3 are independently selected form the group consisting of alkyl, aryl, alkylaryl, cycloalkyl, alcohol, carboxylic acid and ester having 1 to 24 carbon atoms; and (iii) at least one component (B) being a metal dialkyl dithio phosphate salt. The total of ashless components (A) provides to the lubricant composition from 0.010 to 0.080 wt. % phosphorus based on the total weight of the lubricant composition and the total of components (B) provides to the lubricant composition from 0.010 to 0.080 wt. % phosphorus based on the total weight of the lubricant composition.