Lubricating Composition with Self-Assembling Polymers
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Solution Overview
Problem
Existing lubricating compositions face challenges in providing additional elastic lifting force without thickening the oil, and existing high molecular weight flow improvers are unsuitable for hydraulic systems due to high shear conditions.
Innovation Solution
A lubricating composition comprising an oil of lubricating viscosity, 0.1 wt % to 1 wt % of an ethylene-α-olefin copolymer grafted with a polar moiety, and 0.25 wt % to 15 wt % of a poly(meth)acrylate polymer with a block or tapered block copolymer structure, where one block is insoluble in the base oil and the other is soluble, enhancing the normal force and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If viscosity of the lubricant is decreased to improve engine efficiency, then energy consumption is reduced, but hydrodynamic lifting force decreases reducing durability
Solution Approach 1:
The patent employs a composite polymer system combining polyisobutylene (for viscosity modification and energy efficiency) with polyalkylene glycol (for elastic lifting force and durability). This composite approach allows the lubricant to simultaneously achieve reduced viscosity for energy efficiency while maintaining durability through the elastic properties of the polyalkylene glycol component, resolving the contradiction between engine efficiency and durability
Solution Approach 2:
The patent modifies the physical-chemical parameters of the lubricant by introducing specific polymer additives with controlled molecular weights and concentrations. The polyalkylene glycol component specifically alters the elastic properties and normal force characteristics of the lubricant, enabling enhanced durability without requiring increased viscosity, thus resolving the efficiency-durability trade-off
2Stability of the object's composition
If high molecular weight flow improvers are used to improve flow characteristics, then fluid rheology is enhanced, but shear stability deteriorates under high shear conditions
Solution Approach 1:
The patent selects polymers with specific molecular weight parameters and molecular architectures that optimize the balance between flow improvement and shear stability. The polyisobutylene and polyalkylene glycol components are chosen with controlled molecular weights to provide effective viscosity modification while maintaining resistance to shear degradation, resolving the contradiction between flow characteristics and shear stability
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 combination of ethylene-α-olefin copolymer and poly(meth)acrylate polymer synergistically improves the normal force of the lubricating composition, enhancing the durability of lubricating compositions and providing a shear-stable flow improver for hydraulic systems.
Implementation Method 1
viscoelastic lubricating fluids that impart a high normal force
Implementation Method 2
the transition of polymer chains into a non-equilibrium (asymmetrical) conformation. Under equilibrium conditions, polymer chains exist as entangled coils. As these polymers are strained, the chains elongate and any existing entanglements may come apart. Even polymer chains under dilute conditions that are not entangled will deform due to flow. Because Brownian motion tries to return the polymer chains to their equilibrium, average symmetrical state, a stress is generated in the perpendicular, or normal, direction of the shear flow.
Implementation Method 3
Because Brownian motion tries to return the polymer chains to their equilibrium, average symmetrical state, a stress is generated in the perpendicular, or normal, direction of the shear flow.
Implementation Method 4
Existing high molecular weight flow improvers, often based on polyisobutylene, are typically unsuitable for use in hydraulic systems because of the high shear conditions to which they are subjected. Therefore, a need also exists for a shear stable flow improver useful in hydraulic fluids.
Data Source
AI summary
The invention provides a lubricating composition comprising an oil of lubricating viscosity and synergistic mixture of a functionalized ethylene-α-olefin copolymer, a poly(meth)acrylate block polymer having a substantially oil soluble block and a substantially oil insoluble block. The invention also provides a method of lubricating a mechanical device using such a lubricating composition.