Oil Seal Coating Agent Using Large Fluororesin Fillers
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Solution Overview
Problem
Existing oil seal coating agents face challenges in achieving low torque characteristics while maintaining excellent seal performance due to high surface energy of fluororesin particles and limited roughness, leading to increased friction and energy loss.
Innovation Solution
A coating agent comprising 10 to 160 parts by weight of fillers with a particle size of 0.5 to 30 μm, based on isocyanate group-containing 1,2-polybutadiene, prepared as an organic solvent solution, which results in a contact angle of less than 35° with engine oil, improving wettability and reducing dynamic friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fluororesin particles with small particle size (0.1 to 10 μm) are used as filler, then the coating film can be formed, but the surface energy is high making it difficult to improve wettability with oil
Solution Approach 1:
The patent changes the particle size parameter of the filler from the conventional small range (0.1 to 10 μm) to a larger range (10 to 30 μm). This parameter change reduces the surface energy of the filler particles, thereby improving wettability with oil and reducing the contact angle to 35° or less, while still maintaining effective coating film formation.
2Quantity of substance
If fluororesin particles with small particle size (0.1 to 10 μm) are used as filler, then the coating film can be formed, but it is difficult to increase the roughness of the coating surface
Solution Approach 1:
The patent increases the particle size parameter of the filler to 10 to 30 μm, which directly increases the roughness of the coating surface. The larger particles create more pronounced surface irregularities and higher roughness, which improves oil retention and reduces friction, while still forming an effective coating film.
3Force
If coating film is formed to reduce friction, then the torque of oil seal can be reduced, but the coating film may be removed during sliding causing loss of friction reduction effect
Solution Approach 1:
The patent uses a composite material system combining fluororesin particles (10 to 30 μm) with specific rubber base materials (nitrile rubber, fluororubber, or hydrogenated nitrile rubber). This composite structure provides both low friction properties from the fluororesin and high adhesion/durability from the rubber matrix, preventing coating film removal during sliding while maintaining friction reduction.
Solution Approach 2:
The patent applies coating agents with different compositions to different parts of the oil seal. Specifically, the lip seal portion receives a coating with fluororesin particles for low friction, while other portions may have different coatings optimized for their specific functions, ensuring both friction reduction and overall durability.
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 solution effectively enhances oil wettability and reduces the dynamic friction coefficient, achieving low torque characteristics while maintaining excellent seal performance and preventing oil leakage.
Implementation Method 1
a contact angle between a substrate surface coated with the coating agent and engine oil is less than 35°
Implementation Method 2
reduce dynamic friction coefficient in oil
Data Source
AI summary
A coating agent for oil seal comprising 10 to 160 parts by weight of a filler having a particle size of 0.5 to 30 □m based on 100 parts by weight of isocyanate group-containing 1,2-polybutadiene and being prepared as an organic solvent solution, wherein a contact angle between a substrate surface coated with the coating agent and engine oil is less than 35°. The coating agent can improve wettability with oil and reduce dynamic friction coefficient in oil, while increasing the roughness of the coating surface. Thus, low torque characteristics can be achieved, while maintaining excellent seal performance inherent in oil seal.