Block Copolymer Viscosity Modifier for Lubricating Oil Shear Stability
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Solution Overview
Problem
Current lubricating oil compositions using viscosity modifiers face challenges in achieving excellent low-temperature properties and shear stability while maintaining economic efficiency, as they require a balance between viscosity and fluidity, which is difficult to achieve with existing polymers.
Innovation Solution
A block copolymer with specific properties, including a melting point range of -20°C to 100°C, molecular weight distribution of 1.6 to 5.0, and specific thermal and crystallization characteristics, is used as a lubricating oil viscosity modifier to enhance low-temperature properties and shear stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer with low molecular weight is used to improve shear stability, then shear stability is improved, but the amount of viscosity modifier that must be added increases, deteriorating economic efficiency
Solution Approach 1:
The invention changes the molecular weight distribution parameter of the polymer, specifically controlling Mw/Mn to be 2.0 or less. This parameter optimization allows the polymer to achieve both good shear stability and adequate viscosity modification efficiency, resolving the contradiction between shear stability and economic efficiency
Solution Approach 2:
The invention uses a composite polymer structure comprising both a polymer component and an oligomer component with specific molecular weight ranges. This composite structure combines the shear stability benefits of lower molecular weight materials with the viscosity efficiency of higher molecular weight materials, resolving the contradiction between shear stability and amount of additive required
2Quantity of substance
If a polymer with high molecular weight is used to improve economic efficiency by reducing the amount of viscosity modifier added, then economic efficiency is improved, but shear stability deteriorates
Solution Approach 1:
The invention optimizes the molecular weight distribution parameter by controlling Mw/Mn to be 2.0 or less, which allows high molecular weight polymers to maintain good shear stability while reducing the amount of additive needed, thus improving economic efficiency
Solution Approach 2:
The composite structure of polymer and oligomer components with specifically controlled molecular weights creates a synergistic effect where the oligomer component enhances shear stability while the polymer component provides efficient viscosity modification, reducing the total amount of additive required
3Temperature
If the amount of constituent units derived from ethylene is increased to improve low-temperature properties, then low-temperature properties are improved, but the intramolecular composition distribution becomes wide, making it difficult to avoid deterioration
Solution Approach 1:
The invention changes the composition parameters by precisely controlling the ethylene content to be 30-80 mol% and optimizing the molecular weight distribution (Mw/Mn ≤ 2.0). This parameter optimization allows sufficient ethylene content for low-temperature properties while maintaining narrow composition distribution through controlled polymerization
Solution Approach 2:
The invention employs dynamic control of the polymerization process to maintain consistent monomer composition throughout polymerization. By dynamically adjusting polymerization conditions and using appropriate catalyst systems, the intramolecular composition distribution is kept narrow even with optimized ethylene content for low-temperature performance
Data Source
AI summary
A copolymer containing a constituent unit derived from ethylene and a constituent unit derived from an α-olefin having 3 to 20 carbon atoms and satisfying the following requirements (1) to (5): (1) the copolymer has a melting point (Tm) of -20°C to 100°C; (2) the melting point (Tm) and the density D (g/cm3) satisfy the following expression Tm≥1073×D-893 (1); (3) the copolymer has a molecular weight distribution (Mw/Mn) measured by GPC of 1.6 to 5.0; (4) the copolymer has a half-width (ΔThalf) of a melting peak measured by DSC of 90°C or less; and (5) the half-width (ΔThalf) and the melting point (Tm) satisfy the relationship shown by the following expression ΔThalf≤-0.71×Tm+101.4 (2).