Ni-Zn-Cu Ferrite Particles for Resin Dispersion and Resistivity

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Solution Overview

Problem

Ferrite particles used in resin moldings for flexible printed wiring materials exhibit poor dispersibility and surface irregularities, leading to insufficient electrical resistivity and durability issues when high voltage is applied.

Innovation Solution

Ni-Zn-Cu ferrite particles with a specific composition (5-10 wt% Ni, 15-30 wt% Zn, 1-5 wt% Cu, and 25-50 wt% Fe) and a polyhedral shape, having an average diameter of 1-2000 nm, are used to enhance dispersibility and electrical resistivity, allowing for a smooth surface and constant magnetic permeability across a wide frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ferrite particles (20-50 μm) are used in resin moldings, then magnetic properties are achieved, but dispersibility in resin is insufficient and surface irregularities occur

Engineering Contradiction:
Improvemagnetic propertiesVSAvoidsurface smoothness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The ferrite particles are divided into much smaller sizes (1-2000 nm) compared to conventional particles (20-50 μm). This segmentation into nanoscale particles dramatically improves dispersibility in the resin matrix while eliminating surface irregularities, as the fine particles can be uniformly distributed without creating visible defects on the molding surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The particle size parameter is changed from micrometer scale (20-50 μm) to nanometer scale (1-2000 nm). This parameter change fundamentally alters the interaction between filler particles and resin, enabling excellent dispersibility while maintaining necessary magnetic properties through controlled composition (Ni: 5-10 wt%, Zn: 15-30 wt%, Cu: 1-5 wt%, Fe: 25-50 wt%).

Inventive Principle:
Principle #35Parameter changes

2Productivity

If ferrite particles are used to enable magnetic field adsorption for resin removal, then efficiency is improved, but electrical resistivity is insufficient leading to current leakage

Engineering Contradiction:
Improveresin removal efficiencyVSAvoidelectrical resistivity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A composite ferrite material containing multiple elements (Ni-Zn-Cu-Fe) is created with specific composition ranges. This composite structure provides both adequate magnetic properties for field adsorption and high electrical resistivity to prevent current leakage, resolving the contradiction between productivity and reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different elements are strategically distributed within the ferrite particle structure to provide localized functions: Ni and Zn contribute to magnetic properties for adsorption efficiency, while Cu and surface modifications enhance electrical resistivity. This local quality differentiation allows simultaneous achievement of both productivity and reliability requirements.

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 Ni-Zn-Cu ferrite particles achieve high saturation magnetization, low residual magnetization, and high electrical resistivity, ensuring excellent dispersibility and surface smoothness in resin moldings, preventing current leakage and enabling efficient removal of unnecessary resin by magnetic field adsorption.

Implementation Method 1

with use of ferrite particles as filler instead of silicon oxide or the like, the resin film is adsorbed to remove by applying a magnetic field to the resin film

Methodology Applied
Scientific EffectMagnetic field adsorption: Magnetism

Implementation Method 2

the ferrite particles are also required to have a high resistivity such that durability is secured by suppressing generation of current leakage

Methodology Applied
Scientific EffectElectrical resistivity: Electrical Resistance

Data Source

PatentEP3522179B1Ni-zn-cu ferrite particles, resin composition and resin molded body
Publication Date: 2021.11.17 POWDERTECH CO LTD
  • EP3522179B1 patent drawingFigure 1
  • EP3522179B1 patent drawingFigure 2
  • EP3522179B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide ferrite particles having high saturation magnetisation and electrical resistivity, excellent in dispersibility in a resin, a solvent, or a resin composition; a rein composition containing the ferrite particles; and a resin molding composed of the resin composition. A Ni-Zn-Cu ferrite particle is in a single crystalline body having an average particle diameter of 1 to 2000 nm, has a polyhedral particle shape, and comprises 5 to 10 wt% of Ni, 15 to 30 wt% of Zn, 1 to 5 wt% of Cu, and 25 to 50 wt% of Fe.