Polyalkyl(meth)acrylate Shear-Stable Viscosity Index Improvers
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Solution Overview
Problem
Current viscosity index improvers for lubricants face challenges in achieving high shear-resistance while maintaining high viscosity index values, which is crucial for maintaining lubricant performance across varying temperatures and reducing wear on metal parts in engines and transmissions.
Innovation Solution
A polyalkyl(meth)acrylate polymer is developed using a monomer composition comprising 15-35% hydroxylated hydrogenated polybutadiene with a molecular weight of 1,800-2,200 g/mol, 50-60% methyl(meth)acrylate and butyl(meth)acrylate, and 5-35% linear or branched alkyl(meth)acrylates, with a weight ratio of methyl(meth)acrylate to butyl(meth)acrylate between 5:1 and 3:1, resulting in polymers with excellent shear-stability and high viscosity index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyalkyl(meth)acrylate polymers are used as viscosity index improvers, then the viscosity index is improved, but the shear-resistance deteriorates
Solution Approach 1:
The patent changes the molecular weight parameter of the polybutadiene-based macromonomer to a specific range (1,800-2,200 g/mol) and adjusts the compositional parameters (monomer ratios) to achieve optimal balance between viscosity index improvement and shear-resistance. This parameter optimization resolves the contradiction by finding the precise conditions where both properties are satisfied simultaneously.
Solution Approach 2:
The patent creates a composite polymer structure combining polybutadiene-based macromonomers with specific molecular weight characteristics and alkyl(meth)acrylate components. This composite approach allows the polymer to exhibit both high viscosity index improvement capability and enhanced shear-resistance, resolving the contradiction through material composition design.
2Use of energy by moving object
If lubricant viscosity is reduced to improve fuel economy, then energy consumption decreases, but protection of metal parts deteriorates
Solution Approach 1:
The patent utilizes polymers that dynamically adapt their viscosity characteristics based on operating conditions. The specific polymer structure allows the lubricant to maintain low viscosity at operating temperatures for energy efficiency while providing sufficient film strength and protection under high shear conditions, resolving the contradiction between fuel economy and metal part protection.
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 polymer effectively improves the shear-resistance and viscosity index of lubricant formulations, ensuring consistent lubricant performance and protecting metal parts across a wide temperature range.
Implementation Method 1
viscosity index improvers (VIIs) are used to improve the temperature-dependence of the lubricant that is usually illustrated by the viscosity index (VI). The VI is calculated from the kinematic viscosity at 40 °C (KV 40) and the kinematic viscosity at 100 °C (KV 100). The higher the VI the lower is the temperature-dependence of the viscosity of the lubricant
Implementation Method 2
the shear-resistance of the lubricant is an important factor: on one side, the lifetimes of the lubricants are getting longer asking for more resistant lubricants and on the other side the lubricant viscosities are getting lower minimizing the possibility to reduce viscosity due to shear losses without causing any failures in the metal parts
Data Source
AI summary
The invention relates to a polyalkyl(meth)acrylate polymer comprising a polybutadiene-based monomer and preparation process thereof. The invention also relates to the use of said polymers as viscosity index improvers in lubricant formulation and to lubricant compositions comprising said polymer.