Copper Oxide Ultrafine Particles Redispersibility via Extraction
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Solution Overview
Problem
Current methods for producing copper oxide ultrafine particles with primary diameters less than 100 nm face challenges such as excessive particle growth, difficulty in separation, and poor redispersibility, making them unsuitable for industrial-scale production and use as conductive fillers.
Innovation Solution
A method involving the production of soft agglomerates of copper oxide ultrafine particles with primary diameters not exceeding 100 nm, which can be easily redispersed, using techniques like reducing copper carboxyl compounds with hydrazine in an aqueous solution, followed by heating in diethylene glycol to form colloidal dispersions, allowing for efficient separation and redispersion in a suitable solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a surfactant or bulky organic compound is used to protect the surface of ultrafine particles, then particle diameter increase is inhibited, but the particles become difficult to separate and redispersion is poor
Solution Approach 1:
The patent removes the surfactant and bulky organic compound from the particle surface, extracting the harmful element that caused poor separability and redispersibility while maintaining particle size control through alternative means
Solution Approach 2:
The patent changes the surface state parameter from coated (surfactant/bulky compound) to uncoated, fundamentally altering the particle surface properties to enable easy separation and redispersibility while controlling particle diameter through reaction conditions
2Manufacturing precision
If centrifugation is used to separate ultrafine particles from the reaction solution, then particle separation is achieved, but productivity is lowered due to complex operations
Solution Approach 1:
The patent extracts the need for centrifugation by designing the particle formation process to yield easily separable products, eliminating the complex centrifugation operation and its associated productivity losses
Solution Approach 2:
The reaction system automatically separates the particles through simple filtration or decantation without requiring energy-intensive centrifugation, making the separation process self-service and efficient
3Manufacturing precision
If amino groups are used to coordinate to the particle surface, then particle diameter increase is inhibited, but electric conductivity is reduced due to insulating organic compounds
Solution Approach 1:
The patent extracts the amino group coating from the particle surface, removing the insulating layer that reduced electric conductivity while maintaining particle size control through alternative coordination mechanisms
Solution Approach 2:
The patent changes the surface composition parameter from amino group-coated to uncoated, fundamentally altering the electrical properties while maintaining particle diameter control through reaction condition optimization
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 copper oxide ultrafine particles with improved handleability and redispersibility, enabling their use as effective electrically conductive fillers and inks, suitable for industrial applications like printing boards and inkjet coatings.
Implementation Method 1
reducing copper carboxyl compounds with hydrazine in an aqueous solution
Implementation Method 2
heating in diethylene glycol to form colloidal dispersions
Data Source
AI summary
A soft agglomerate of copper oxide ultrafine particles which has an average primary particle diameter of not more than 100 nm and an average secondary particle diameter of not less than 0.2 μm and of producing the soft agglomerate by (1) forming ultrafine copper oxide by reducing a cuprous carboxyl compound in an aqueous solution, with hydrazine and/or a hydrazine derivative, optionally with a base and optionally with organic compounds, such as alcohol (e.g., ethylene glycol or ethanol), ether, ester or amide; and simultaneously or separately applying an agglomerating force, e.g., agglomerating agent; to produce copper oxide soft agglomerate. Alternatively (2), forming a colloidal dispersion of cuprous oxide ultrafine particles by heating and reducing at least one copper compound (e.g., copper carboxyl, copper alkoxy and copper diketonate compound) at a temperature of not lower than 160 ° C. and forming a soft agglomerate by either further heating the colloidal dispersion or by adding an agglomerating agent, e.g., monoalcohol, ether, ester, nitrite, amide and imide. Colloidal dispersions are formed by separating and redispersing the soft agglomerate. Cuprous oxide ultrafine particles are used as fillers, such as electroconductive paste and electroconductive ink, and manufacture of copper-oxide ultrafine particle colloid dispersion liquid used as inkjet ink.