Soft Magnetic Resin Composition Suppressing Spring Back
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Solution Overview
Problem
High filling of soft magnetic particles in magnetic films leads to spring back phenomena, resulting in gaps and defects, particularly during high temperature treatments, which compromise the magnetic properties and film integrity.
Innovation Solution
A soft magnetic resin composition comprising flat soft magnetic particles, a resin component with a combination of epoxy resin, phenol resin, and acrylic resin, where the epoxy and phenol resins have three or more functional groups, and the acrylic resin content is 25% or more, ensuring a high content of soft magnetic particles while suppressing spring back and gap formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content ratio of soft magnetic particles in a magnetic film is increased to improve magnetic properties, then magnetic permeability is improved, but gaps (voids) occur in the soft magnetic film due to spring back phenomenon
Solution Approach 1:
The invention changes the chemical composition parameters of the resin by specifying functional group counts (three or more for epoxy and phenol resins) and content ratios (acrylic resin at 25 mass% or more), which alters the resin's elastic properties to suppress spring back while maintaining high particle content for good magnetic properties
Solution Approach 2:
The invention uses a composite resin system combining epoxy resin, phenol resin, and acrylic resin with specific proportions, creating a material with balanced properties that prevents gap formation while allowing high soft magnetic particle content (40% by volume or more) for excellent magnetic permeability
2Reliability
If the thickness of the magnetic film is increased to improve shielding effect, then magnetic field shielding is improved, but the device size increases which contradicts the demand for smaller electronic devices
Solution Approach 1:
The invention changes the resin composition parameters to achieve high particle content (40% by volume or more) in a thin film, which improves magnetic permeability and shielding effect per unit thickness, allowing thinner films to achieve the same shielding performance as thicker conventional films
3Reliability
If high filling of soft magnetic particles is used to improve magnetic properties, then magnetic permeability is improved, but peeling or appearance defects occur during high temperature treatment such as reflow treatment
Solution Approach 1:
The invention specifies parameter ranges for resin composition (epoxy resin with three or more functional groups, phenol resin with three or more functional groups, acrylic resin at 25 mass% or more) that provide thermal stability, preventing peeling and appearance defects during high temperature reflow treatment while maintaining high particle content for good magnetic properties
Solution Approach 2:
The composite resin system of epoxy resin, phenol resin, and acrylic resin in specific proportions creates a thermally stable matrix that bonds well with soft magnetic particles, preventing peeling during high temperature treatment while allowing high particle content (40% by volume or more) for excellent magnetic permeability
Data Source
Figure 1
AI summary
A soft magnetic resin composition contains flat soft magnetic particles, and a resin component containing an epoxy resin, a phenol resin, and an acrylic resin. The epoxy resin consists of only an epoxy resin having three or more functional groups, the phenol resin consists of only a phenol resin having three or more functional groups, and the content ratio of the acrylic resin in the resin component is 25 mass% or more.