Magnetic Recording Medium Copolymer Binding Agent

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Solution Overview

Problem

Existing magnetic recording media face challenges in simultaneously improving electromagnetic conversion characteristics and durability due to limitations in the binding agents used, which affect the dispersibility and mechanical properties of ferromagnetic powders.

Innovation Solution

A magnetic recording medium comprising a non-magnetic support with a magnetic layer containing ferromagnetic powder and a binding agent, where the magnetic layer includes a compound with a polyalkyleneimine chain and a vinyl polymer chain, enhancing dispersibility and hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polar group is introduced to a binding agent to increase dispersibility of ferromagnetic powder, then dispersibility is improved, but excessive introduction decreases dispersibility and electromagnetic conversion characteristics

Engineering Contradiction:

Improveelectromagnetic conversion characteristicsVSAvoidbinding agent composition complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a copolymer binding agent combining polyurethane resin and polyacrylonitrile resin in specific ratios (70:30 to 90:10). This composite material approach allows the polyurethane component to provide mechanical strength while the polyacrylonitrile component introduces polar groups for enhanced ferromagnetic powder dispersibility, resolving the contradiction between dispersibility and electromagnetic conversion characteristics

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the urethane group concentration within a specific range (5-20 mass%) and controls the copolymer ratio to balance dispersibility and electromagnetic performance. By precisely controlling these parameters, the invention achieves optimal dispersibility without excessive polar group introduction that would harm electromagnetic conversion characteristics

Inventive Principle:

Principle #35Parameter changes

2Strength

If the concentration of urethane group in the binding agent is increased to improve mechanical properties, then durability is improved, but solubility decreases and dispersibility of ferromagnetic powder deteriorates

Engineering Contradiction:

Improvemechanical properties of binding agentVSAvoiddispersibility of ferromagnetic powder

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The copolymer binding agent combines polyurethane resin (providing mechanical strength through urethane groups) with polyacrylonitrile resin (providing solubility and dispersibility). This composite structure allows the urethane group concentration to be optimized for mechanical properties (5-20 mass%) while the polyacrylonitrile component maintains solubility and dispersibility, resolving the contradiction between strength and dispersibility

Inventive Principle:

Principle #40Composite materials

3Duration of action of stationary object

If a binding agent with high mechanical properties is used to improve durability, then durability is improved, but dispersibility of ferromagnetic powder decreases

Engineering Contradiction:

Improvedurability of magnetic recording mediumVSAvoidelectromagnetic conversion characteristics

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent employs a copolymer binding agent where polyurethane resin provides the mechanical strength for durability while polyacrylonitrile resin ensures dispersibility of ferromagnetic powder. The specific composition ratio (70:30 to 90:10) and controlled urethane group concentration (5-20 mass%) enable simultaneous achievement of durability and electromagnetic conversion characteristics

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The binding agent has different functional regions: the polyurethane segments provide mechanical strength and durability, while the polyacrylonitrile segments provide polar groups for dispersibility. This local differentiation of properties within the binding agent structure allows simultaneous optimization of durability and electromagnetic conversion characteristics

Inventive Principle:

Principle #3Local quality

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 improves both electromagnetic conversion characteristics and durability of the magnetic recording medium by optimizing the dispersibility and mechanical properties of the ferromagnetic powder within the magnetic layer.

Implementation Method 1

a polar group is introduced to a binding agent, in order to increase dispersibility by causing the binding agent to be efficiently adsorbed to the surface of the ferromagnetic powder

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

improve electromagnetic conversion characteristics of a magnetic recording medium

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS11670334B2Magnetic recording medium, magnetic recording and reproducing device and composition for magnetic recording medium including polyalkyleneimine compound

Publication Date: 2023.06.06 FUJIFILM CORP

AI summary

The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer further includes a compound including a polyalkyleneimine chain and a vinyl polymer chain. The composition for a magnetic recording medium includes: ferromagnetic powder; and a compound including a polyalkyleneimine chain and a vinyl polymer chain.