Oil Seal Coating Composition for Low Torque and Seal Durability
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Solution Overview
Problem
Existing coating agents for oil seals face challenges in achieving low torque characteristics while maintaining excellent dispersibility and seal performance, as they often struggle with wettability and friction reduction due to high surface energy fluororesin particles and small particle sizes, which also affect the balance between film strength and abrasion resistance.
Innovation Solution
A coating agent comprising 10 to 90 parts by weight of fillers, including silicone resin particles of 0.5 to 10 μm and fluororesin particles of 0.1 to 2 μm, used in a ratio of 20 to 80 wt. % of the total filler amount, based on isocyanate group-containing 1,2-polybutadiene, improves wettability and reduces dynamic friction by increasing surface roughness without compromising film strength or abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fluororesin particles with small particle size (0.1 to 10 μm) are used to improve wettability, then surface energy increases, but it becomes difficult to significantly improve wettability with oil and increase surface roughness
Solution Approach 1:
The patent combines two types of filler particles with different particle sizes: fluororesin particles (0.1 to 2 μm) and silicone resin particles (0.5 to 10 μm). The smaller fluororesin particles contribute to low surface energy and good wettability, while the larger silicone resin particles provide surface roughness. This combination resolves the contradiction by making both small particles (for wettability) and large particles (for roughness) work together synergistically.
2Force
If a coating film is formed using material with low friction coefficient to reduce friction, then friction decreases, but the coating film may be removed during sliding
Solution Approach 1:
The patent uses a composite coating system consisting of isocyanate group-containing 1,2-polybutadiene as the base resin combined with fluororesin and silicone resin particles. This composite material provides both low friction characteristics (from fluororesin) and enhanced durability (from the polybutadiene matrix and silicone resin), preventing coating film removal during sliding while maintaining low friction.
3Stability of the object's composition
If dispersant is added in large amount to improve dispersibility of PTFE, then dispersibility improves, but the strength of the film formed from the coating agent is reduced
Solution Approach 1:
The patent introduces isocyanate group-containing 1,2-polybutadiene as an intermediary substance that facilitates the dispersion of fluororesin particles without requiring large amounts of dispersant. The polybutadiene acts as a compatibilizer that interacts with both the filler particles and the coating matrix, achieving good dispersibility while maintaining film strength.
4Strength
If filler other than PTFE is used to maintain film strength, then film strength is maintained, but abrasion resistance is lowered
Solution Approach 1:
The patent employs a composite filler system combining fluororesin particles (which provide low friction and good dispersibility) with silicone resin particles (which enhance abrasion resistance). This composite filler approach maintains film strength while improving abrasion resistance, overcoming the limitation of using single-type fillers.
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 combined use of silicone resin and fluororesin particles enhances dispersibility and wettability, achieving low torque characteristics and maintaining excellent seal performance by reducing the dynamic friction coefficient and improving abrasion resistance, while avoiding the need for dispersants and preventing particle aggregation.
Implementation Method 1
increasing the roughness of the sliding surface
Implementation Method 2
reduces dynamic friction by increasing surface roughness
Implementation Method 3
improve wettability with oil by increasing the roughness of the sliding surface
Data Source
AI summary
A coating agent for oil seal comprising 10 to 90 parts by weight of a filler and 10 to 40 parts by weight of a wax, based on 100 parts by weight of isocyanate group-containing 1,2-polybutadiene, and being prepared as an organic solvent solution, wherein as the filler, silicone resin particles having a particle size of 0.5 to 10 μm and fluororesin particles having a particle size of 0.1 to 2 μm are each used at a ratio of 20 to 80 wt. % of the total filler amount. The coating agent for oil seal can exhibit excellent seal performance inherent in oil seal while maintaining excellent dispersibility of the coating agent, and can further achieve low torque characteristics.