Epoxy Metal Powder Paste for Low-Volatile Insulating Cores
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Solution Overview
Problem
The use of metal powder pastes in industrial applications faces challenges such as increased viscosity and reduced fluidity due to high metal powder blending ratios, leading to performance degradation in cured products due to volatile organic solvents, which can cause voids, mechanical strength loss, and poor insulation properties.
Innovation Solution
A metal powder paste comprising a metallic element-containing powder, an epoxy group-containing compound, and a curing agent, with a thermogravimetric reduction rate of 5% or less after heat curing at 180°C, and a coefficient of thermal expansion (CTE) of 40 ppm/°C or less, utilizing an amine-based or imidazole-based curing agent and a liquid epoxy resin to minimize solvent usage and maintain product integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the blending ratio of metal powder is increased to enhance strength and electrical conductivity, then the properties of the formed body are improved, but the viscosity of the paste increases and fluidity decreases
Solution Approach 1:
A volatile component is introduced as an intermediary substance to reduce paste viscosity and improve fluidity, allowing high metal powder content to be processed effectively. The volatile component temporarily modifies rheological properties during application, then evaporates during curing, leaving no residue that would compromise final product properties.
Solution Approach 2:
The viscosity of the paste is dynamically controlled by adjusting the amount of volatile component added. This parameter change allows the paste to achieve optimal fluidity for processing while maintaining high metal powder blending ratio, and the volatile component is subsequently removed through evaporation during the curing process.
2Ease of operation
If an organic solvent is added to adjust viscosity, then the fluidity of the paste is improved, but volumetric shrinkage occurs and the substrate may be exposed
Solution Approach 1:
A volatile component with low boiling point is used as a temporary viscosity modifier that serves its purpose during application and then completely evaporates during curing. This disposable approach avoids the permanent presence of solvents that would cause shrinkage and substrate exposure, as the component leaves no residue.
3Ease of operation
If an organic solvent is used to adjust viscosity, then the fluidity is improved, but properties of the cured product deteriorate due to stress strain accumulation and void formation
Solution Approach 1:
The volatile component is designed to completely evaporate during the curing process, converting what would normally be a harmful residue into a beneficial temporary processing aid. By selecting a component with appropriate volatility, the paste achieves improved fluidity during application, and the component then disappears during curing, preventing stress strain accumulation and void formation that would compromise mechanical strength.
4Reliability
If the amount of organic solvent is reduced, then the insulation properties are improved, but the viscosity adjustment capability is reduced
Solution Approach 1:
The volatile component acts as a temporary intermediary that provides viscosity control during processing without compromising insulation properties in the final product. Unlike conventional organic solvents that leave residues, this component completely evaporates, ensuring that insulation properties are maintained while still providing the necessary viscosity adjustment capability during application.
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 reduces the amount of volatile components, suppressing performance degradation and achieving excellent insulation properties and low CTE in the cured product, thereby enhancing mechanical strength and reliability.
Implementation Method 1
a paste containing a metallic element-containing powder, an epoxy group-containing compound, and a curing agent
Implementation Method 2
thermogravimetric reduction rate is 5% or less after heat curing at 180° C.
Implementation Method 3
volumetric shrinkage occurs with the volatilization of the organic solvent
Data Source
AI summary
Provided is a paste including: a metallic element-containing powder; an epoxy group-containing compound; and a curing agent, wherein a thermogravimetric reduction rate is 5% or less after heat curing at 180° C. The paste can be suitably used as a material for a magnetic core of an inductor or as a material for filling between conductors of a coil, and is capable of easily providing a formed body having excellent insulation properties.