Olefin-Ester Copolymer Viscosity Modifiers for Lubricants

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Solution Overview

Problem

Current lubricant formulations face challenges in achieving a balance between power transfer efficiency and elastohydrodynamic (EHD) film thickness, as additives that improve viscosity index and reduce friction often compromise EHD film protection, and those that enhance EHD film thickness may hinder power transfer efficiency.

Innovation Solution

A lubricant composition comprising a specific blend of an esterified copolymer derived from α-olefin and ethylenically unsaturated carboxylic acid monomers, combined with a polymer containing olefin monomers, and optional performance additives, optimized to provide a balance between EHD film thickness and power transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymeric materials or viscosity modifiers are added to improve EHD film thickness, then EHD film thickness is improved, but power transfer efficiency decreases

Engineering Contradiction:

ImproveEHD film thicknessVSAvoidpower transfer efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by carefully controlling the molecular weight, composition, and concentration of the copolymer viscosity modifier. By optimizing these parameters, the copolymer provides adequate EHD film thickness while minimizing energy losses and maintaining power transfer efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite approach by combining the copolymer viscosity modifier with specific base oils and complementary additives. This composite lubricant formulation achieves a balance between EHD film protection and power transfer efficiency that neither component could achieve alone

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If lubricant additives are used to provide good power transfer efficiency through lower viscosity, then power transfer efficiency is improved, but EHD film thickness becomes inadequate

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidEHD film thickness

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The copolymer's molecular weight and composition parameters are specifically designed to provide viscosity improvement without excessive thickening. This allows the lubricant to maintain low enough viscosity for efficient power transfer while still providing adequate EHD film thickness under load

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If viscosity index is improved and friction is reduced, then power transfer efficiency is improved, but EHD film protection is compromised

Engineering Contradiction:

Improvefriction and power transferVSAvoidEHD film protection

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The copolymer exhibits dynamic viscosity modification behavior, providing shear thinning characteristics that reduce friction and improve power transfer at operating conditions, while maintaining adequate viscosity for EHD film formation under high load conditions. This dynamic response allows the lubricant to adapt to different operating regimes

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP2814921B1Mixtures of olefin-ester copolymer with polyolefin as viscosity modifier

Publication Date: 2017.11.08 THE LUBRIZOL CORP

AI summary

A lubricant composition of an oil of lubricating viscosity; an esterified copolymer with a backbone comprising units derived from (i) an alpha-olefm monomer of at least about 6 carbon atoms and (ii) an ethylenically unsaturated carboxylic acid in a mole ratio of 1 :3 to 3: 1; and a polymer comprising olefin monomer units of 3 to 5 carbon atoms, wherein at least 50 percent by weight of such units contain fewer than 6 carbon atoms and wherein less than 5 percent by weight of such units are ethylene monomer units; exhibits good power transfer efficiency and elastohydrodynamic film thickness.