Ear-of-Rice Copper Particles via Galvanic Displacement
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Solution Overview
Problem
Current methods for manufacturing copper dendrimer-type conductive fillers are costly, energy-intensive, and difficult to scale due to high temperatures and complex equipment requirements, limiting productivity and practical application in conductive pastes.
Innovation Solution
A room-temperature synthesis process involving the addition of zinc powder to a copper precursor solution to produce ear-of-rice-shaped copper particles, which are easily synthesized in large quantities and mixed with resin formulations, reducing production costs and improving conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional dendrimer-type copper fillers are used to reduce silver cost, then material cost is reduced, but mixing uniformity deteriorates due to increased surface area ratio and difficulty of resin penetration
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the copper particle has a dendrimer core with a smooth outer shell. The dendrimer core provides high surface area for conductivity, while the smooth outer shell ensures uniform mixing and resin penetration. This resolves the contradiction by having different local properties in different parts of the same particle.
Solution Approach 2:
The patent uses composite materials by combining dendrimer-type copper structure with a smooth surface coating or modification. This creates a hybrid particle that exhibits both the high surface area characteristics of dendrimers and the mixing properties of smooth particles, resolving the contradiction between conductivity enhancement and mixing uniformity.
2Use of energy by stationary object
If zinc powder is added to copper precursor solution for room-temperature synthesis, then production cost and energy consumption are reduced, but particle shape control becomes more challenging
Solution Approach 1:
The patent applies parameter changes by systematically optimizing the zinc powder to copper precursor ratio, pH value, temperature, and stirring conditions to achieve consistent ear-of-rice shape formation. By controlling these parameters within specific ranges, the patent achieves both low energy consumption (room temperature) and precise particle shape control.
Solution Approach 2:
The patent uses pH adjustment and specific additives as intermediaries to control the reaction between zinc powder and copper precursor. These intermediaries mediate the reduction process to ensure uniform nucleation and growth of the ear-of-rice shaped particles, resolving the shape control challenge while maintaining room-temperature synthesis.
3Quantity of substance
If copper is used as conductive filler instead of silver, then cost is reduced, but corrosion resistance deteriorates leading to surface oxidation and reduced electrical conductivity
Solution Approach 1:
The patent accepts the limited corrosion resistance of copper as a trade-off for using inexpensive material, but compensates through the dendrimer structure that increases conductivity efficiency. The ear-of-rice shaped copper particles are designed to maximize conductivity within their service life, making the shorter lifespan acceptable given the cost advantage.
Solution Approach 2:
The patent creates a composite structure where copper particles are combined with resin formulation containing curing agents and additives that provide corrosion protection. This composite approach maintains the low cost of copper while improving its reliability and corrosion resistance in the final conductive paste product.
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 method enables the production of low-cost, high-quality ear-of-rice-shaped copper particles with improved mixing properties and electrical conductivity, facilitating mass production and efficient conductive paste formulation.
Implementation Method 1
a first step of preparing a copper precursor solution, a second step of adjusting the pH of the copper precursor solution, a third step of adding a zinc powder to the pH-adjusted copper precursor solution, a fourth step of synthesizing the ear-of-rice-shaped copper particles by stirring the copper precursor solution, to which the zinc powder is added
Data Source
AI summary
The present invention relates to ear-of-rice-shaped copper particles. The technical gist thereof is a method of manufacturing ear-of-rice-shaped copper particles, ear-of-rice-shaped copper particles manufactured thereby, and a conductive paste using the same. The method includes a first step of preparing a copper precursor solution, a second step of adjusting the pH of the copper precursor solution, a third step of adding a zinc powder to the pH-adjusted copper precursor solution, a fourth step of synthesizing the ear-of-rice-shaped copper particles by stirring the copper precursor solution, to which the zinc powder is added, for a predetermined time, and a fifth step of separating, washing, and then drying the synthesized ear-of-rice-shaped copper particles.