Polyalkyl Methacrylate Viscosity Index Improver for Shear-Stable Lubricants

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Solution Overview

Problem

Current viscosity index improvers for lubricants face challenges in maintaining high viscosity index while ensuring good shear-resistance, which is crucial for efficient fuel economy and engine protection without causing mechanical degradation.

Innovation Solution

A poly alkyl(meth)acrylate polymer is developed using a polybutadiene-based macromonomer in combination with high amounts of linear or branched propyl(meth)acrylate, resulting in a polymer with high viscosity index and excellent shear-stability when used in lubricant formulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If polymeric additives are added to improve viscosity index, then the temperature-dependence of viscosity is reduced, but the additives undergo shear stress and mechanically degrade over time

Engineering Contradiction:
Improveviscosity indexVSAvoidshear-resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the molecular weight distribution of polybutadiene macromonomers (500-50,000 g/mol) and the composition ratios of monomers in the polymer. By adjusting these parameters, the polymer achieves optimal balance between viscosity index improvement and shear resistance, resolving the contradiction between composition stability and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material principles by creating a poly alkyl(meth)acrylate polymer that combines polybutadiene-based macromonomers with other monomer units. This composite structure integrates the advantages of different monomer components, achieving both high viscosity index and excellent shear stability that neither component could provide alone.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If lubricant viscosity is reduced for fuel economy, then fuel consumption decreases, but the viscosity must still be high enough to protect metal parts

Engineering Contradiction:
Improvefuel economyVSAvoidprotection capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies dynamics by formulating a lubricant with viscosity index improver polymer that dynamically adapts its viscosity characteristics. The polymer maintains lower base viscosity for fuel economy while providing viscosity enhancement and protection capability when needed, allowing the lubricant to optimize performance across different operating conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11795413B2Viscosity index improver and lubricant compositions thereof
Publication Date: 2023.10.24 EVONIK OPERATIONS GMBH

AI summary

The invention relates to a poly alkyl(meth)acrylate polymer comprising polybutadiene-based monomer units and a process for preparing the same. The invention also relates to the use of said polymer as a viscosity index improver in lubricant formulation and to lubricant compositions comprising said polymer.