Fine-Particle Urea Grease Composition for Metal-Resin Wear Resistance

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Solution Overview

Problem

Existing grease compositions fail to provide adequate wear resistance for lubrication in sliding portions composed of metal and resin materials, particularly in large-sized vehicles where increased forces can lead to resin material defects and wear.

Innovation Solution

A grease composition containing a base oil, a urea-based thickener with particles having an area-based arithmetic average particle diameter of 2.0 µm or less, and melamine cyanurate, which enhances wear resistance by allowing the urea-based thickener to effectively spread and fill defects in the resin material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass fiber is mixed into resin material to improve strength, then the strength of the resin material is improved, but the glass fibers scratch and break on the resin surface, causing defects and increased wear

Engineering Contradiction:
Improvestrength of resin materialVSAvoidwear resistance of resin material
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The grease composition acts as an intermediary substance between the metal sliding surface and the glass fiber-reinforced resin. It fills the defects on the resin surface caused by broken glass fibers and provides a protective lubricating film, preventing direct contact and further damage between the metal surface and defective resin areas, thereby reducing wear while maintaining the strength benefits of glass fiber reinforcement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical and chemical parameters of the lubrication system by introducing a specifically formulated grease composition with controlled viscosity (10-420 mm²/s at 40°C) and specific additive packages. This parameter optimization allows the grease to effectively penetrate and fill surface defects in the glass fiber-reinforced resin while providing adequate lubrication under high load conditions

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional grease compositions are used for lubrication, then the basic lubrication function is provided, but adequate wear resistance is not achieved in metal-resin sliding portions under high load

Engineering Contradiction:
Improvelubrication functionVSAvoidwear resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The grease composition employs a composite formulation combining multiple functional components: base oil providing lubrication, urea-based thickener for consistency and film formation, and melamine cyanurate as a solid lubricant. This composite structure creates a synergistic effect that delivers both adequate lubrication function and superior wear resistance in metal-resin sliding portions under high load conditions

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters of the grease composition, including viscosity (10-420 mm²/s at 40°C), thickener content (0.1-20% by mass), and melamine cyanurate content (0.1-10% by mass). These parameter adjustments ensure the grease maintains proper consistency for lubrication while providing enhanced wear protection through the solid lubricant components

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 grease composition exhibits excellent wear resistance by improving the holding power and reducing wear in metal-resin sliding interfaces, even under high loads, thus preventing resin material defects.

Implementation Method 1

the area-based arithmetic average particle diameter of the particles is 2.0 μm or less, as measured by a laser diffraction/scattering method

Methodology Applied
Scientific EffectLaser diffraction/scattering:

Implementation Method 2

addition of melamine cyanurate, which is a solid lubricant, to a lubricant composition has been studied

Methodology Applied
Scientific EffectSolid lubrication: Lubrication

Data Source

PatentEP4317382B1Grease composition
Publication Date: 2025.08.13 IDEMITSU KOSAN CO LTD
  • EP4317382B1 patent drawingFigure 1
  • EP4317382B1 patent drawingFigure 2
  • EP4317382B1 patent drawing

AI summary

Provided is a grease composition containing a base oil (A), a urea-based thickener (B), and melamine cyanurate (C), wherein particles containing the urea-based thickener (B) in the grease composition satisfy the following requirement (I), and the grease composition has excellent wear resistance. Requirement (I): The particles have an area-based arithmetic average particle diameter of 2.0 µm or less, as measured by a laser diffraction/scattering method. It is preferred that the particles containing the urea-based thickener (B) in the grease composition further satisfy the following requirement (II). Requirement (II): The particles have a specific surface area of 0.5 × 105 cm2/cm3 or more, as measured by a laser diffraction/scattering method.