Magnetic Recording Medium Lubricant Layer Composition
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Solution Overview
Problem
Magnetic recording media face challenges in achieving high recording density and preventing contamination due to voids in the lubricant layer, which reduces coverage and bonding force, leading to environmental substance penetration and contamination by ionic impurities.
Innovation Solution
A magnetic recording medium with a lubricant layer comprising compounds A and B, represented by specific general formulas, at a predetermined ratio, achieving a total surface energy of 25.5 mJ/m2 or less, ensuring high coverage and bonding force to the protective layer, thereby preventing contamination and enhancing environmental resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of the lubricant layer is reduced to increase recording density, then recording density is improved, but voids are easily formed in the lubricant layer reducing coverage and bonding force
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricant layer by incorporating compounds with specific molecular structures (fluorinated compounds, compounds with carboxyl groups, compounds with hydroxyl groups) in controlled ratios. This compositional parameter change enables the formation of a continuous, void-free lubricant layer even at reduced thicknesses of 1 nm or less, thereby maintaining high coverage and bonding force while achieving increased recording density
Solution Approach 2:
The patent uses a composite lubricant layer formed by combining multiple compounds with different functional groups (fluorinated compounds for low surface energy and high coverage, carboxyl-containing compounds for bonding to protective layer, hydroxyl-containing compounds for molecular alignment). This composite approach creates a lubricant layer that maintains structural integrity and prevents void formation at thin thicknesses, resolving the contradiction between reduced thickness for higher density and maintained reliability
2Productivity
If the lubricant layer thickness is reduced, then recording density is improved, but environmental substances penetrate through voids causing contamination
Solution Approach 1:
The patent modifies the chemical composition parameters of the lubricant layer by incorporating fluorinated compounds that provide low surface energy and high coverage, along with compounds containing carboxyl and hydroxyl groups that enhance molecular alignment and continuity. This compositional change eliminates voids in the lubricant layer even at thicknesses of 1 nm or less, creating a barrier that prevents penetration of environmental substances and contaminants while maintaining reduced thickness for high recording density
3Reliability
If conventional lubricants are used, then the lubricant layer can be formed, but sufficient bonding force and coverage cannot be achieved with thin layers
Solution Approach 1:
The patent changes the chemical composition parameters by selecting compounds with specific functional groups: fluorinated compounds for low surface energy and high coverage, carboxyl-containing compounds for strong bonding to the carbon protective layer, and hydroxyl-containing compounds for molecular alignment. This parameter optimization enables the formation of a continuous, well-bonded lubricant layer at thicknesses of 1 nm or less, achieving sufficient bonding force and coverage that conventional lubricants cannot attain at such thin dimensions
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 results in a magnetic recording medium with improved recording density and stable magnetic recording/reproducing characteristics by preventing contamination and maintaining high bonding force and coverage, even with a thin lubricant layer, thus enhancing environmental resistance.
Implementation Method 1
the lubricant layer which is formed on and in contact with the protective layer
Implementation Method 2
frictional force between the magnetic recording medium and the magnetic head sliding on the magnetic recording medium is remarkably reduced
Data Source
AI summary
The present invention relates to a magnetic recording medium in which a lubricant layer contains a compound A represented by general formula (1) and a compound B represented by general formula (2), satisfying (A/B)=0.2 to 3.0, and has an average thickness of 0.8 nm to 2 nm. R1—C6H4OCH2CH(OH)CH2OCH2—R2—CH2OCH2CH(OH)CH2OH . . . (1) (R1 is an alkoxy group having 1 to 4 carbon atoms. R2 is —CF2O(CF2CF2O)x(CF2O)yCF2— (x, y=0 to 15), —CF2CF2O(CF2CF2CF2O)zCF2CF2— (z=1 to 15), —CF2CF2CF2O(CF2CF2CF2CF2O)nCF2CF2CF2— (n=0 to 4). HOCH2CF2CF2O(CF2CF2CF2O)mCF2CF2CH2OCH2CH(OH)CH2OH . . . (2) (m is an integer).