Oil Seal Coating Composition for Low Torque and Oil Wettability
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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, due to issues with filler dispersibility, abrasion resistance, and wettability with oil.
Innovation Solution
A coating agent comprising 10 to 90 parts by weight of a filler and 10 to 40 parts by weight of wax, using silicone resin particles of 0.5 to 10 µm and fluororesin particles of 0.1 to 2 µm at a ratio of 20 to 80 wt.%, along with isocyanate group-containing 1,2-polybutadiene, to improve dispersibility and reduce dynamic friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If only fluororesin particles with small particle size (0.1 to 10 μm) are used as filler, then the coating agent can be applied, but the surface energy of fluororesin is high making it difficult to significantly improve wettability with oil, and the roughness of the coating surface cannot be increased
Solution Approach 1:
The patent combines fluororesin particles (20-80 wt%) with silicone resin particles (20-80 wt%) to create a composite filler system. This composite approach allows the fluororesin to provide low friction properties while the silicone resin increases surface roughness and improves oil wettability, resolving the contradiction between using small particle size fillers and achieving good wettability.
2Stability of the object's composition
If a dispersant is added to improve the dispersibility of PTFE, then the dispersibility improves, but if a large amount of dispersant is added, the strength of the film formed from the coating agent is reduced
Solution Approach 1:
The patent changes the chemical composition parameters by introducing silicone resin particles as a alternative dispersing agent. This chemical parameter change allows for improved PTFE dispersibility through the silicone resin's surface properties without requiring large amounts of traditional dispersants that would compromise film strength.
3Stability of the object's composition
If filler other than PTFE is used, then the dispersibility issue is addressed, but abrasion resistance is lowered
Solution Approach 1:
The patent creates a composite filler system where fluororesin particles (providing low friction and wear resistance) are combined with silicone resin particles (providing good dispersibility). This composite material approach allows both requirements to be met simultaneously: the fluororesin maintains abrasion resistance while the silicone resin ensures dispersibility.
4Force
If the coating film is removed during sliding, then the friction reduction effect is lost, but maintaining the coating film requires high strength
Solution Approach 1:
The composite filler system of fluororesin and silicone resin creates a coating film with optimized mechanical properties. The fluororesin provides low friction characteristics while the silicone resin contributes to film integrity and adhesion, allowing the coating to maintain both friction reduction effectiveness and sufficient strength to prevent premature removal during sliding.
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 fluororesin and silicone resin particles enhances dispersibility, increases surface roughness for improved wettability, and reduces dynamic friction, resulting in low torque characteristics and excellent seal performance.
Implementation Method 1
The combined use of fluororesin particles and silicone resin particles as the fillers to be contained in the coating agent ensures the dispersibility of the coating agent
Implementation Method 2
a coating is selected so that the contact angle between the coated oil seal surface and engine oil is less than 35°, while the roughness of the coating surface increases, wettability with oil can be improved, and dynamic friction coefficient in oil can be reduced
Implementation Method 3
The friction of oil seal can be reduced by forming a coating film using of a material having a friction coefficient lower than that of the sealing material on the sliding surface of the oil seal lip part
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.