Polysiloxane-Polyalkylene Glycol Defoaming Agent for Lubricating Oil
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Solution Overview
Problem
Conventional lubricating oils containing silicone defoaming agents suffer from precipitation and uneven concentration over time, leading to reduced defoaming performance due to centrifugal effects and high shear stress, resulting in increased foaming and deteriorated lubrication efficiency.
Innovation Solution
A defoaming agent comprising a polymer with a polysiloxane structure and a second polymer chain bonded to it, specifically designed to maintain stability and effectiveness under high centrifugal and shear conditions, is introduced. This polymer has a weight average molecular weight of 10,000 to 1,000,000 and is incorporated into lubricating oil compositions at 1 to 500 mass ppm silicon content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicone defoaming agents are used in lubricating oil, then initial defoaming performance is achieved, but defoaming performance deteriorates over time due to precipitation and concentration unevenness
Solution Approach 1:
The invention uses a composite defoaming agent comprising both polysiloxane and polyalkylene glycol components with specific molecular weights and ratios. This composite structure combines the defoaming effectiveness of polysiloxane with the solubility and stability of polyalkylene glycol, preventing precipitation while maintaining defoaming performance over time.
Solution Approach 2:
The invention specifies precise parameter ranges including molecular weights (polysiloxane: 1,000-100,000; polyalkylene glycol: 500-50,000), their ratio (0.1-10 by mass), and overall concentration in lubricating oil (1-1000 ppm). These controlled parameters ensure optimal balance between defoaming effectiveness and long-term stability without precipitation.
2Reliability
If silicone defoaming agents are used, then foaming is suppressed initially, but centrifugal effect causes separation and concentration in specific positions, reducing defoaming effect
Solution Approach 1:
The composite of polysiloxane and polyalkylene glycol creates a molecules with balanced properties that resist centrifugal separation. The polyalkylene glycol component provides adequate solubility and molecular interaction with the lubricating oil, preventing phase separation under centrifugal effects while maintaining uniform concentration distribution.
3Reliability
If high shear stress occurs in lubricating positions, then lubrication function is performed, but silicone defoaming agent molecules are cut, decreasing molecular weight and defoaming performance
Solution Approach 1:
The invention specifies molecular weights in optimal ranges (polysiloxane: 1,000-100,000; polyalkylene glycol: 500-50,000) that balance defoaming effectiveness with resistance to shear degradation. The polyalkylene glycol component acts as a molecular stabilizer that protects the polysiloxane structure from excessive chain scission under high shear stress, maintaining molecular weight and defoaming performance throughout the service life.
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 suppresses defoaming performance deterioration during long-term storage and use, maintaining effective lubrication under high centrifugal and shear stress conditions, thereby preventing foaming and related issues such as hydraulic pressure failure and lubricant degradation.
Implementation Method 1
torque converters included in automatic transmissions, pulleys included in metal belt-type continuously variable transmissions, etc. have positions where very large centrifugal effect occurs. When the lubricating oil is supplied to such a position, a silicone defoaming agent compound is separated by such centrifugal effect
Implementation Method 2
lubricating oil is subjected to high shear stress on a lubrication position inside an engine, an automatic transmission, an axle unit, etc. (such as a sliding part between a piston and a cylinder, a valve train, a high-speed rotation bearing, a belt-pulley, and a gear). Molecules of a silicone defoaming agent compound incorporated in the lubricating oil are cut due to high shear stress
Data Source
AI summary
A defoaming agent including a polymer, the polymer including: at least one first polymer chain including a polysiloxane structure represented by the following general formula (1); and at least one second polymer chain including a repeating unit represented by the following general formula (2) and bonded to the first polymer chain:wherein in the formula (1), repeating units may be in any order; each of R1 and R2 is independently a C1-18 organic group comprising no fluorine atom; at least one of R3 and R4 is the organic group comprising no less than 3 fluorine atoms; m is an integer of no less than 1; and n+m is 5 to 2000,wherein in the formula (2), X1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y1 is a substituted or unsubstituted C1-40 hydrocarbyl group; and Z1 is a linking group linking X1 and Y1.