Grease Composition with Ionic Liquid Antistatic Agents
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Solution Overview
Problem
Existing grease compositions used in mechanical parts, such as rolling bearings, suffer from high volume resistivity leading to electrical charging and electrolytic corrosion, with known antistatic agents like carbon black causing noise and environmental concerns, or being expensive and incompatible with petroleum oils.
Innovation Solution
A grease composition incorporating Li(CF3SO2)2N and Li(CF3SO2)3C as antistatic agents, dissolved in suitable solvents, which effectively reduces charging tendency and maintains excellent acoustic properties when used in small amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black is added as an antistatic agent, then electric conductivity is improved, but noise is generated by oscillation on the rolling surface
Solution Approach 1:
The patent changes the physical state of the antistatic agent from solid particles (carbon black) to liquid form (ionic liquid), which eliminates the oscillation noise on the rolling surface while maintaining electric conductivity. The ionic liquid's liquid state allows it to flow smoothly without the mechanical oscillation that causes noise with particulate materials.
Solution Approach 2:
The patent uses a small amount of ionic liquid (0.01-5% by mass) to achieve the desired antistatic effect, replacing the need for large amounts of carbon black. This minimal addition avoids the thickening problem and reduces noise while providing sufficient electric conductivity.
2Reliability
If a large amount of carbon black is added to impart electric conductivity, then electric conductivity is improved, but the grease composition becomes thickened
Solution Approach 1:
The patent changes the form of the antistatic agent from solid particles to liquid ionic liquid, which dissolves in the base oil without causing thickening. This parameter change from particulate to liquid state allows for effective electric conductivity enhancement while maintaining the grease's original viscosity characteristics.
Solution Approach 2:
The patent creates a composite system where the ionic liquid integrates with the base oil and grease matrix, forming a homogeneous mixture that provides electric conductivity without the aggregation and thickening effects associated with carbon black particles.
3Reliability
If chromium alkyl salicylate and fatty acid calcium salt are used as antistatic agents, then electric conductivity is improved, but adverse effects on human body and environment occur
Solution Approach 1:
The patent uses a small concentration of ionic liquid (0.01-5% by mass) to achieve the antistatic effect, replacing toxic compounds like chromium alkyl salicylate and fatty acid calcium salt. This minimal addition of environmentally benign ionic liquid provides the necessary electric conductivity without harmful environmental or health effects.
4Reliability
If ionic liquid is used as an antistatic agent, then electric conductivity is improved, but cost increases and compatibility with petroleum base oils decreases
Solution Approach 1:
The patent optimizes the concentration parameter of the ionic liquid to a low range (0.01-5% by mass), which reduces cost and improves compatibility with petroleum base oils. At these low concentrations, the ionic liquid provides sufficient electric conductivity while minimizing any potential incompatibility issues with the base oil system.
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 prevents electrical charging and electrolytic corrosion while maintaining good acoustic properties, achieving volume resistivity below 50.0×10^7 Ωm and minimal noise, even when used in small amounts, effectively protecting surrounding control equipment.
Implementation Method 1
the grease composition uses as the base oil mineral oils such as paraffinic oils and naphthenic oils or synthetic oils such as ester-based synthetic oils, synthetic hydrocarbon oils, ether-based synthetic oils and the like. Those base oils themselves show considerably high volume resistivities. Therefore, it is known that the bearing or mechanical part filled with a grease composition containing any of the above-mentioned base oils becomes an insulator, thereby being electrically charged
Implementation Method 2
When a large difference in electric potential is generated between the inner and outer rings, a current flows through a thin lubricating oil film to cause sparking, which will produce the problem of so-called electrolytic corrosion where the rolling surface of the bearing and the contact surface of the rolling elements are impaired
Data Source
AI summary
The invention provides a grease composition containing a thickener, a base oil and an antistatic agent, where the antistatic agent includes at least one selected from the group consisting of Li(CF3SO2)2N and Li(CF3SO2)3C; and a mechanical part where the above-mentioned grease composition is packed. The composition of the invention shows satisfactory results in the antistatic properties and the acoustic property.