Lubricating Oil Additive Package Using Block Copolymer Friction Modifiers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The stability issues between detergents and friction modifiers in additive packages for lubricating oils, particularly when glycerol monoesters are used as friction modifiers, lead to sediment, haze, or gel formation, which complicates the production of stable lubricating oil compositions, especially when overbased detergents like calcium salicylates are present.
Innovation Solution
Incorporating oil-soluble block or graft copolymers derived from hydroxycarboxylic acids and polyalkylene glycols as friction modifiers in lubricating oil compositions, which include overbased metal hydroxybenzoate detergents, to enhance stability and friction reduction properties, while minimizing the use of glycerol monoesters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glycerol monoester friction modifiers are used in additive packages with overbased detergents, then friction reduction is improved, but stability deteriorates leading to sediment, haze or gel formation
Solution Approach 1:
The patent changes the chemical parameters of the friction modifier by using block copolymers with specific molecular weights and compositions (polylactic acid blocks combined with polyalkylene glycol blocks) instead of traditional glycerol monoesters. This parameter change maintains friction reduction capability while eliminating the instability and sediment formation issues associated with glycerol monoesters when combined with overbased detergents.
Solution Approach 2:
The patent employs composite material structure by creating block copolymers that combine different polymer blocks (polylactic acid and polyalkylene glycol) with distinct properties. The polylactic acid blocks provide friction reduction while the polyalkylene glycol blocks improve solubility and stability, creating a composite material that resolves the contradiction between friction reduction and additive package stability.
2Use of energy by moving object
If the amount of friction modifier is increased to improve fuel economy, then fuel economy is improved, but stability deteriorates and sediment formation increases
Solution Approach 1:
The patent changes the molecular parameters of the friction modifier to enable higher concentrations without stability loss. The block copolymer structure with controlled molecular weights (polylactic acid blocks of 1000-5000 g/mol and polyalkylene glycol blocks of 500-2000 g/mol) allows the friction modifier to be used at higher levels to improve fuel economy while maintaining additive package stability and preventing sediment formation.
3Reliability
If overbased metal hydroxybenzoate detergents are used in lubricating oil compositions, then detergent performance is improved, but stability deteriorates when combined with traditional friction modifiers
Solution Approach 1:
The patent changes the parameters of the friction modifier component to be compatible with overbased metal hydroxybenzoate detergents. By using block copolymers with specific molecular weights and compositions rather than traditional glycerol monoesters, the friction modifier no longer reacts adversely with the overbased detergents, allowing both components to coexist stably while maintaining their respective performances.
Data Source
AI summary
An additive package is disclosed for preparing an automotive crankcase lubricating oil composition for an internal combustion engine. The additive package is made by admixing: (i) 50 mass% or less of an oil of lubricating viscosity; (ii) 50 mass% or less of at least one overbased metal detergent, preferably at least one overbased metal hydroxybenzoate detergent,; (iii) 50 mass% or less of an oil-soluble block or graft co-polymer of at least one polymeric block A which is derived from a hydroxycarboxylic acid and at least one polyalkylene block B which is a residue of a polyalkylene glycol, and (iv) optionally, at least one further additive selected from a dispersant, an antioxidant and/or an antiwear agent. The additive package includes less than 2.00 mass %, preferably less than 1.50 mass %, of a friction modifier which is a monoester of a C5 to C30 carboxylic acid and which is free of nitrogen. Component (ii) is preferably an overbased metal hydroxybenzoate detergent. Component (iii) acts as a friction modifier and can be used as a replacement for a friction modifier such as glycerol monooleate. The additive package exhibits improved stability.