Comb-Shaped Polymer Viscosity Index Improver for Fuel Economy
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Solution Overview
Problem
Current lubricating oil compositions containing viscosity index improvers are insufficient in improving fuel consumption reducing properties, and there is a need for a viscosity index improver that can enhance these properties while maintaining favorable characteristics of the lubricating oil composition.
Innovation Solution
A lubricating oil composition incorporating a comb-shaped polymer viscosity index improver, which has a high degree of entanglement between molecules, resulting in reduced viscosity changes with temperature, thereby improving fuel consumption reducing properties. The composition includes a base oil and additives such as pour-point depressants, metal-based detergents, and anti-wear agents, and is produced by blending the viscosity index improver with the base oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional viscosity index improvers (polymethacrylate-based) are used, then the lubricating oil composition shows acceptable fuel consumption reducing properties, but the fuel consumption reducing properties are not sufficient
Solution Approach 1:
The patent changes the molecular structure parameters of the viscosity index improver by introducing a comb-shaped polymer with specific repeating units (polyolefin macromonomer, alkyl (meth)acrylate, styrene-based monomer) and controlling weight average molecular weight and composition ratios. This structural parameter change results in improved fuel consumption reducing properties while maintaining other lubricating performance characteristics.
Solution Approach 2:
The patent creates a composite viscosity index improver structure combining multiple repeating units in a comb-shaped polymer architecture. The main chain includes polyolefin macromonomer units with side chains of alkyl (meth)acrylate and styrene-based monomers, forming a composite molecular structure that achieves superior fuel consumption reducing properties compared to conventional single-type polymers.
2Stability of the object's composition
If viscosity index improvers with high degree of entanglement are used, then viscosity changes with temperature are reduced, but the complexity of the polymer structure increases
Solution Approach 1:
The patent segments the polymer structure into distinct functional components: a main chain backbone and comb-shaped side chains. The main chain provides structural continuity while the side chains (derived from polyolefin macromonomers) provide entanglement and viscosity stabilization. This segmentation allows independent optimization of each component's contribution to overall performance.
Solution Approach 2:
The patent transitions from linear polymer structures to three-dimensional comb-shaped architectures. The side chains extend in multiple dimensions from the main chain, creating a spatial network that increases molecular entanglement and reduces viscosity changes with temperature. This dimensional expansion provides enhanced thermal stability without excessive complexity.
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 use of a comb-shaped polymer viscosity index improver in the lubricating oil composition significantly enhances fuel consumption reducing properties while maintaining favorable viscosity and performance characteristics, particularly in high-temperature regions, by minimizing viscosity changes due to temperature fluctuations.
Implementation Method 1
with respect to a viscosity index improver containing a comb-shaped polymer, as it has a structure whose degree of entanglement between molecules is large, a change in viscosity attributable to a temperature environment or a change in temperature is small
Data Source
AI summary
Provided is a viscosity index improver including a comb-shaped polymer and satisfying the following requirement (I) or (II). Requirement (I): With respect to a solution having the viscosity index improver dissolved in a mineral oil and having a solid component concentration of 25 mass%, a ratio [(G')/(G")] of a storage modulus (G') to a loss modulus (G") of the solution as measured under prescribed conditions with a measuring temperature of 70°C is 0.40 or more. Requirement (II): With respect to a solution (α) at 25°C having the viscosity index improver dissolved in a mineral oil and having a solid component concentration of 25 mass% and a solution (β) resulting from subjecting the solution (α) to temperature rise to 100°C at a prescribed temperature rise rate and then cooling to 25°C at a prescribed cooling rate, a ratio of a storage modulus (G') of the solution (β) to a storage modulus (G') of the solution (α) as measured under prescribed conditions with a measuring temperature of 25°C is 2.0 or more.