Magnetic Recording Medium Binder Dispersion and Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic recording media face challenges in achieving both improved dispersion of ferromagnetic powder and enhanced durability of the magnetic layer, as better mechanical properties of binders enhance durability but compromise powder dispersion, and vice versa.
Innovation Solution
Incorporating a compound denoted by formula (1) with a weight average molecular weight of 1,000 to 20,000, featuring a heterocyclic group for adsorption and a polymer group for steric repulsion, along with ferromagnetic powder and a binder, to form a magnetic layer that improves dispersion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the concentration of urethane groups in the binder is increased to enhance mechanical properties, then the durability of the magnetic layer is improved, but the solubility of the binder decreases and dispersion of ferromagnetic powder deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by incorporating specific copolymer components (aromatic polyisocyanate with 10-40 mol% of isocyanate groups) to optimize the balance between mechanical properties and solubility. This parameter adjustment allows the binder to maintain both durability and dispersion capability
Solution Approach 2:
The patent uses a composite binder system combining polyurethane resin with specific copolymer components containing aromatic polyisocyanate. This composite material approach enables the binder to exhibit both high mechanical strength and adequate solubility for ferromagnetic powder dispersion
2Quantity of substance
If polar groups are introduced into the binder to enhance dispersion of ferromagnetic powder, then the dispersion is improved, but excessive polar groups decrease the dispersion and mechanical properties
Solution Approach 1:
The patent optimizes the polar group content by controlling the copolymerization components, specifically using aromatic polyisocyanate with controlled isocyanate group concentration (10-40 mol%). This parameter control ensures adequate polarity for dispersion without excessive polar groups that would harm mechanical properties
3Manufacturing precision
If the particle size of ferromagnetic powder is reduced to increase recording density, then the magnetic force per bit decreases, but the frequency of contact between reproduction head and magnetic layer increases causing more scratching
Solution Approach 1:
The patent uses a composite binder material with optimized polyurethane resin and copolymer components that provides enhanced mechanical strength and adhesion. This composite binder protects the magnetic layer from scratching caused by increased head contact frequency, thereby maintaining reliability despite reduced particle size
Solution Approach 2:
The patent adjusts the binder's mechanical properties by controlling the copolymerization ratio and isocyanate group concentration, creating a binder with optimal hardness and elasticity that can withstand the increased mechanical stress from frequent head contact
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 compound enhances the dispersion of ferromagnetic powder and imparts suitable extensibility to the magnetic layer, thereby achieving both improved dispersion and durability, reducing the risk of scratching and increasing the magnetic layer's resistance to mechanical stress.
Implementation Method 1
the heterocyclic group (X in formula (1)) that is capable of adsorbing to the surface of the ferromagnetic powder
Implementation Method 2
a polymer group for steric repulsion
Data Source
AI summary
An aspect of the present invention relates to a magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the magnetic layer further comprises a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and is denoted by formula (1):wherein, in formula (1), A denotes a monovalent substituent, R1 denotes a single bond or a divalent connecting group, and m denotes an integer ranging from 2 to 4, multiple instances of A and R1 that are present can be identical or different, at least one of the multiple instances of A that are present denotes a monovalent polymer group and X denotes a heterocyclic group of valence m.