Star Polymer Lubricating Composition for Engine Oil

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Solution Overview

Problem

Existing lubricating compositions for internal combustion engines fail to simultaneously achieve acceptable viscosity index, oil blend thickening capabilities, shear stability, good low temperature viscosity performance, and low viscosity modifier treatment level while maintaining appropriate lubricating performance.

Innovation Solution

A lubricating composition comprising 0.001 wt % to 15 wt % of a polymethacrylate polymer with radial or star architecture, 0.1 wt % to 15 wt % of an overbased detergent, and 0.1 wt % to 25 wt % of a dispersant, obtained from RAFT or ATRP polymerization processes, combined with an oil of lubricating viscosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a viscosity index improver with C16 to C30 alkyl (meth)acrylate monomer is used at 5 weight percent or more, then viscosity index is improved, but low temperature viscosity performance deteriorates due to waxy texture

Engineering Contradiction:

Improveviscosity indexVSAvoidlow temperature viscosity performance

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the molecular architecture parameter from linear to star-shaped polymer structure, and adjusts the monomer composition parameters (using C10-C15 alkyl (meth)acrylate as main component with 70-90 wt%, and limiting C16-C30 alkyl (meth)acrylate to 5-15 wt%). This combination of parameter changes achieves improved viscosity index while preventing waxy texture formation, thereby maintaining good low temperature viscosity performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer system by combining multiple monomer types in specific proportions: C10-C15 alkyl (meth)acrylate (70-90 wt%), C16-C30 alkyl (meth)acrylate (5-15 wt%), and optionally other complementary monomers (0-30 wt%). This composite approach allows the polymer to exhibit both high viscosity index improvement capability and good low temperature fluidity, resolving the contradiction between these two properties

Inventive Principle:

Principle #40Composite materials

2Reliability

If complex anionic polymerization processes are used to prepare star polymers, then polymer performance is improved, but process complexity increases

Engineering Contradiction:

Improvepolymer performanceVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex anionic polymerization mechanism with a free radical polymerization mechanism using RAFT or ATRP techniques. This substitution simplifies the process conditions (no need for strictly anhydrous and oxygen-free environments) while still achieving well-defined star polymer architectures with controlled molecular weights and polydispersity, thus maintaining polymer performance while reducing process complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces RAFT agents or ATRP catalysts as intermediaries to mediate the polymerization process. These intermediaries enable controlled radical polymerization that can form star polymers with defined architectures without requiring the complex conditions of anionic polymerization, thereby simplifying the overall process while maintaining product quality

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If high amounts of polymer are used to achieve acceptable viscosity index, then viscosity index is improved, but fuel economy deteriorates

Engineering Contradiction:

Improveviscosity indexVSAvoidfuel economy

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the polymer architecture parameter to star-shaped structure and optimizes the monomer composition (C10-C15 alkyl (meth)acrylate 70-90 wt%, C16-C30 alkyl (meth)acrylate 5-15 wt%). This parameter optimization enables the polymer to achieve high viscosity index improvement efficiency, allowing acceptable viscosity index to be obtained at lower polymer concentrations (0.1-10 wt%), thereby reducing energy consumption and improving fuel economy

Inventive Principle:

Principle #35Parameter changes

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 composition provides improved fuel economy, reduces deposit and sludge formation, and maintains effective lubricating performance at low temperatures, while minimizing the need for complex anionic polymerization processes.

Implementation Method 1

A lubricating composition comprising 0.001 wt % to 15 wt % of a polymer with radial or star architecture

Methodology Applied

Scientific EffectPolymer thickening:

Implementation Method 2

obtained from RAFT or ATRP polymerization processes

Methodology Applied

Scientific EffectRAFT polymerization:

Implementation Method 3

obtained from RAFT or ATRP polymerization processes

Methodology Applied

Scientific EffectATRP polymerization:

Data Source

PatentEP2021442B1Star polymer lubricating composition

Publication Date: 2016.08.17 THE LUBRIZOL CORP

AI summary

The invention provides a lubricating composition containing (a) 0.001 wt % to 15 wt % of a polymer with radial or star architecture; (b) an overbased detergent; (c) a dispersant; and (d) an oil of lubricating viscosity. The invention further provides a method for lubricating a mechanical device with the lubricating composition.