Acrylic Block Copolymer Lubricating Oil Additive

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Solution Overview

Problem

Conventional acrylic lubricating oil additives with wide molecular weight distributions suffer from low shear stability and short service life, requiring high addition amounts to achieve desired viscosity index improvements.

Innovation Solution

A lubricating oil additive comprising an acrylic block copolymer with a weight-average molecular weight between 10,000 to 1,000,000 and a narrow molecular weight distribution of 1.5 or below, specifically designed to enhance viscosity index and thickening effects with a small addition amount.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a polymer with wide molecular weight distribution is used, then the thickening effect is achieved, but the shear stability deteriorates and service life becomes short

Engineering Contradiction:
Improvethickening effectVSAvoidshear stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the molecular weight distribution parameter from wide to narrow (Mw/Mn ≤ 1.5) while maintaining the thickening effect. This parameter change resolves the contradiction by selecting polymers with specific molecular weight ranges (10,000-1,000,000) that provide both effective thickening and improved shear stability, eliminating the need for high addition amounts while ensuring long service life.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a polymer with low molecular weight is used, then the shear stability is improved, but the thickening effect deteriorates and addition amount must be increased

Engineering Contradiction:
Improveshear stabilityVSAvoidthickening effect
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the molecular weight parameter by specifying a narrow distribution within a specific range (Mw: 10,000-1,000,000, Mw/Mn: 1.5 or below). This resolves the contradiction by finding the optimal molecular weight window that maintains effective thickening while ensuring sufficient shear stability, eliminating the need to increase addition amounts.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If a polymer with wide molecular weight distribution is used, then the addition amount can be reduced, but the service life becomes short

Engineering Contradiction:
Improveaddition amountVSAvoidservice life
Core Design Contradiction:
Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The patent changes the molecular weight distribution parameter to narrow (Mw/Mn ≤ 1.5) while maintaining moderate addition amounts. This resolves the contradiction by selecting polymers with controlled molecular weights that provide both effective performance at low addition amounts and long service life through improved resistance to shear degradation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7718588B2Lubricating oil additive containing acrylic polymer and lubricating oil compositions
Publication Date: 2010.05.18 KURARAY CO LTD

AI summary

A lubricating oil additive containing at least one acrylic block copolymer having a weight-average molecular weight of 10,000 to 1,000,000 and a molecular weight distribution [ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), i.e., Mw/Mn ratio] of 1.5 or below; and lubricating oil compositions containing the additive. The lubricating oil additive exhibits a thickening effect higher than those of conventional acrylic lubricating oil additives and can improve the viscosity index of lubricating oil even when added in a small amount. Further, the additive can also improve the low-temperature characteristics, flow characteristics, and shear stability. The lubricating oil compositions enable energy saving and can lengthen the lifetime of lubricating oil and reduce the load on the global environment.