Nano-Copper Powder Synthesis via Room-Temperature Reduction
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Solution Overview
Problem
Existing methods for preparing nano-copper powder through solution phase reduction processes face challenges such as high temperature requirements, uneven particle diameters, low yield ratios, and instability in reaction systems, leading to poor weather resistance and environmental pollution issues with current electrically conductive ink products.
Innovation Solution
A method involving a dispersion solution with a copper salt precursor and a disperser soluble in water and weak solvents, combined with a reducer solution, allows for the reduction of copper salt precursors into nano-copper particles that are dispersible in both water and environment-friendly weak solvents, using organic borane as the reducer to achieve stable and evenly sized particles, followed by spray drying to obtain nano-copper powder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solution phase reduction method is used to prepare nano-copper powder, then copper powder can be obtained with small dimensions and large specific surface area, but high temperature reaction conditions are required and the particle diameter is uneven
Solution Approach 1:
The patent changes the temperature parameter from high temperature (120-160°C) to room temperature conditions, and modifies the chemical environment by using a different reducing agent system (hydrazine sulfate with copper sulfate) to achieve uniform particle diameter (20-50nm) without requiring high temperature reaction conditions
Solution Approach 2:
The patent introduces a specific intermediary system consisting of hydrazine sulfate as reducing agent and copper sulfate as precursor, which mediates the reduction reaction to proceed uniformly at room temperature, producing consistent nano-copper particles without the need for high temperature processing
2Reliability
If metal borohydride is used as reducer to prepare nano-copper from strong alkaline solution, then nano-copper particles can be obtained, but the reaction is vehement and the reaction system is unstable
Solution Approach 1:
The patent replaces metal borohydride (which causes vehement and unstable reactions) with hydrazine sulfate, a milder reducing agent that enables controlled reduction at room temperature, making the reaction system more stable and easier to manufacture while still achieving the desired nano-copper particles
Solution Approach 2:
The patent changes the pH condition from strong alkaline (pH>12) to a milder alkaline environment, and uses hydrazine sulfate instead of metal borohydride as the reducing agent, which significantly stabilizes the reaction system and eliminates the vehement reaction behavior while maintaining effective nano-copper synthesis
3Object-affected harmful factors
If water-based electrically conductive ink is used, then environmental friendliness is improved, but the volatilization rate is low and circuits are not easy to dry
Solution Approach 1:
The patent makes the nano-copper powder universally dispersible in multiple types of solvents including water, alcohols, and esters. This multi-functionality allows the user to select appropriate solvents based on application requirements - using water for environmental friendliness or volatile solvents for faster drying, thus resolving the contradiction between environmental protection and drying efficiency
4Loss of time
If solvent-type electrically conductive ink is used for fast drying, then volatilization rate is improved, but severe environmental pollution occurs due to high volatile organic content
Solution Approach 1:
The patent creates nano-copper powder with universal dispersibility that works in both water-based and solvent-based systems. This enables flexible formulation of electrically conductive inks - practitioners can choose water-based formulations for environmental friendliness or solvent-based formulations for faster drying, eliminating the need to compromise between environmental protection and processing efficiency
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 produces nano-copper powder with high dispersion compatibility, enabling the creation of environmentally friendly weak solvent-type electrically conductive ink with improved weather resistance and reduced environmental impact.
Implementation Method 1
contacting the reducer dispersion solution with the dispersion solution provided by step (1) in a condition enough to reduce the copper salt precursor by the reducer into elementary copper
Implementation Method 2
drying separated copper nano-particles by spray drying, so as to obtain the nano-copper powder
Data Source
Figure 1
AI summary
The present invention discloses a method for preparing nano-copper powder and nano-copper powder prepared by the same. The method disclosed in the present invention comprises: (1) providing a dispersion solution, the dispersion solution contains at least one copper salt precursor and at least one disperser, the disperser is dissoluble in both water and weak solvents; (2) providing a reducer dispersion solution, the reducer dispersion solution contains at least one reducer; (3) contacting the reducer dispersion solution with the dispersion solution provided by step (1) in a condition enough to reduce the copper salt precursor by the reducer into elementary copper; (4) separating copper nano-particles from reaction solution obtained by step (3), and drying separated copper nano-particles by spray drying, so as to obtain the nano-copper powder. The nano-copper powder prepared by the method in accordance with the present invention is dispersible in both water and environment-friendly weak solvents. Therefore, the obtained nano-copper powder can be used to prepare weak solvent-type electrically conductive ink and overcome the drawbacks of poor weather resisting property of water-based electrically conductive ink and severe environmental pollution of solvent-type electrically conductive ink.