Electromagnetic Wave-Absorbing Composition for Stable Molding
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Solution Overview
Problem
Existing electromagnetic wave-absorbing compositions containing thermoplastic resin or thermoplastic elastomer and soft-magnetic metal powder exhibit increased fluidity when heated, leading to overfilling during molding and adversely affecting mass-productivity of molded articles.
Innovation Solution
Incorporating a specific amount of a phosphite-based or phosphate-based compound into the composition, along with a Fe-Cr-Si-based soft-magnetic metal powder and thermoplastic resin or elastomer, suppresses fluidity increases while maintaining electromagnetic wave absorption performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoplastic resin or thermoplastic elastomer containing soft-magnetic metal powder is used for electromagnetic wave absorption, then electromagnetic wave absorption performance is improved, but fluidity increases when heated causing overfilling during molding
Solution Approach 1:
The invention changes the chemical composition parameters of the resin system by specifying particular resin types (polyester, polyamide, polycarbonate, acrylic, vinyl chloride resin) and their molecular weight ranges, along with controlled ratios between different resins. This parameter optimization ensures the composition maintains appropriate viscosity and melt strength during processing while preserving electromagnetic wave absorption capabilities through controlled soft-magnetic metal powder content (5-60 parts by mass per 100 parts resin).
Solution Approach 2:
The invention creates a composite material system combining multiple resin types with soft-magnetic metal powder. The composite consists of thermoplastic resin (5-60 parts by mass per 100 parts resin of total resin), where the resin blend provides balanced rheological properties. The soft-magnetic metal powder content is controlled at 5-60 parts by mass per 100 parts resin to ensure electromagnetic wave absorption while avoiding excessive fluidity increase during heating.
2Reliability
If soft-magnetic metal powder is added to thermoplastic resin to achieve electromagnetic wave absorption, then electromagnetic wave absorption performance is improved, but the composition becomes difficult to mold due to fluidity control issues
Solution Approach 1:
The invention optimizes physical parameters including soft-magnetic metal powder particle size (0.1-10 μm average diameter), resin molecular weight ranges, and compositional ratios. These parameter changes ensure the composition has appropriate viscosity and melt strength for easy molding while maintaining electromagnetic wave absorption performance through controlled powder content (5-60 parts by mass per 100 parts resin).
Solution Approach 2:
The invention applies local quality control by specifying particular resin types with appropriate molecular weights for different application requirements. The soft-magnetic metal powder is distributed uniformly at controlled concentrations (5-60 parts by mass per 100 parts resin) to ensure consistent electromagnetic wave absorption properties throughout the molded product while maintaining overall moldability.
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 composition achieves excellent electromagnetic wave absorption with reduced fluidity during heating, ensuring consistent molding and improved productivity of molded articles.
Implementation Method 1
a predetermined amount of at least one selected from a phosphite-based compound and a phosphate-based compound is further contained therein, whereby an increase in fluidity when the composition is heated can be suppressed
Implementation Method 2
the composition has an electromagnetic wave absorption energy P, shown in the following equation (1), at 79 GHz of 5 kW/m3
Data Source
AI summary
The present invention aims to provide an electromagnetic wave-absorbing composition comprising a thermoplastic resin or a thermoplastic elastomer, exhibiting electromagnetic wave absorption performance, and suppressing an increase in fluidity when heated. The composition of the present invention comprises a component (A) that is at least one selected from a thermoplastic resin and a thermoplastic elastomer and a component (B) that is a Fe-Cr-Si-based soft-magnetic metal powder at a mass ratio (component (A)/component (B)) in a range of 5/95 to 80/20, further comprises a component (C) that is at least one selected from a phosphite-based compound and a phosphate-based compound in an amount of 0.02 to 1.4 parts by mass relative to 100 parts by mass in total of the component (A) and the component (B), and has an electromagnetic wave absorption energy P at 79 GHz of 5 kW/m3 or more.