Boronic Ester-Modified Polyalkyl(Meth)Acrylates for Reversible Oil Thickening

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Solution Overview

Problem

Existing viscosity index improvers for lubricating oils suffer from irreversible degradation under mechanical stress, leading to a decline in viscosity and thickening properties, especially at higher temperatures, and there is a need for polymers that can associate thermo-reversibly to maintain stability over a broad temperature range.

Innovation Solution

Development of boronic ester-modified polyalkyl(meth)acrylate copolymers with specific monomer compositions and molecular weights, capable of forming association-related thickeners through thermo-reversible chemical bonds, which can be used in lubricating oil compositions at low treat rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high molecular weight polymers are used as viscosity index improvers, then thickening efficiency is improved, but irreversible degradation under mechanical stress occurs leading to viscosity loss

Engineering Contradiction:
Improvethickening efficiencyVSAvoidstability under mechanical stress
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the molecular weight parameter of the polymer from high to low range, and introduces dynamic covalent bonds (boronic ester-diol complexes) that can reversibly form and break. This allows the polymer to maintain low molecular weight (avoiding degradation) while achieving thickening efficiency through thermal association at operating temperatures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system combining low molecular weight polyalkyl(meth)acrylate backbone with boronic ester functional groups and diol-containing additives. This composite structure enables both low molecular weight (reducing degradation) and effective thickening through intermolecular bonding between boronic esters and diols.

Inventive Principle:
Principle #40Composite materials

2Reliability

If low molecular weight polymers are used, then degradation under mechanical stress is reduced, but thickening efficiency decreases

Engineering Contradiction:
Improvestability under mechanical stressVSAvoidthickening efficiency
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent introduces dynamic covalent bonding through boronic ester-diol complexes that can reversibly form and break. At low temperatures, bonds break allowing polymer chains to move freely; at high temperatures, bonds form creating association that increases viscosity. This dynamic behavior allows low molecular weight polymers to achieve high thickening efficiency conditionally.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes temperature as a controlling parameter to switch between bonded and unbonded states. The boronic ester-diol complex formation is temperature-dependent, allowing the same low molecular weight polymer to exhibit different effective viscosities at different temperatures, achieving both stability and thickening efficiency.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If polymers are used to improve viscosity index, then fuel economy is improved, but irreversible degradation leads to permanent viscosity loss

Engineering Contradiction:
Improvefuel consumptionVSAvoidviscosity stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical nature of polymer bonds from permanent covalent bonds to dynamic non-covalent boronic ester-diol complexes. These complexes can reversibly form and break based on temperature and stress conditions, allowing the lubricant to maintain stable viscosity properties over time while still providing fuel economy benefits through reduced friction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of mechanical stress (which breaks polymer chains) into a beneficial reversible process. Instead of permanent degradation, the dynamic bonds temporarily break under stress then reform, actually protecting the polymer from irreversible damage while maintaining lubrication performance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 boronic ester-modified polyalkyl(meth)acrylate copolymers provide stable viscosity index improvement over a broad temperature range, maintaining lubricant properties and enhancing fuel efficiency in vehicles.

Implementation Method 1

boronic ester functional groups... can associate and exchange chemical bonds in a thermo-reversible way

Methodology Applied
Scientific EffectCoordination chemistry: Chemical Bonding

Implementation Method 2

Increasing temperature increases the solvency of the oil, which, in turn, promotes the uncoiling of the polymer and results in a larger hydrodynamic volume

Methodology Applied
Scientific EffectThermal uncoiling: Thermal Expansion

Data Source

PatentEP4441176B1Boronic ester modified polyalkyl(METH)acrylate polymers
Publication Date: 2025.10.01 EVONIK OPERATIONS GMBH
  • EP4441176B1 patent drawingFigure 1
  • EP4441176B1 patent drawingFigure 2
  • EP4441176B1 patent drawing

AI summary

The present invention is directed to boronic ester-modified polyalkyl(meth)acrylate polymers, their use to prepare thermo-associative polymers and method for their preparation.