Cuprous Oxide Dispersion for Transparent Antibacterial Coatings

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Solution Overview

Problem

Existing cuprous oxide nanoparticle dispersion methods, such as microemulsion, are complex and limit solvent types, making it difficult to achieve high antibacterial performance and transparency in coating films, especially when increasing cuprous oxide concentration.

Innovation Solution

A cuprous oxide particle dispersion liquid comprising cuprous oxide particles, a phosphate ester-based anionic surfactant, and an organic solvent, with controlled particle diameters and surfactant amounts, is used to create a coating agent composition that improves dispersibility and transparency, and when combined with a binder resin, forms a high-transparency, high-antibacterial coating film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cuprous oxide concentration is increased to improve antibacterial performance, then antibacterial property is improved, but transparency of coating film deteriorates

Engineering Contradiction:
Improveantibacterial performanceVSAvoidtransparency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The cuprous oxide particles are segmented into small primary particles (2-80 nm) that form secondary particles (50-150 nm) through controlled aggregation. This segmentation allows higher concentration of cuprous oxide to be incorporated while maintaining transparency, as the small particle sizes scatter less light compared to larger aggregates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the particle size parameters of cuprous oxide, specifically controlling the average primary particle diameter to 2-80 nm and average secondary particle diameter to 50-150 nm. This parameter change enables the coating to maintain transparency even at higher cuprous oxide concentrations, resolving the contradiction between antibacterial performance and transparency.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If microemulsion method is used to improve dispersibility of cuprous oxide, then dispersibility is improved, but synthesizing process complexity increases

Engineering Contradiction:
ImprovedispersibilityVSAvoidsynthesizing process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses a specific surfactant as an intermediary substance to achieve dispersibility of cuprous oxide particles. The surfactant mediates between the cuprous oxide particles and the solvent, enabling stable dispersion without requiring the complex microemulsion synthesis process. This simplifies the overall synthesizing process while maintaining good dispersibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If microemulsion method is used to disperse cuprous oxide, then dispersibility is improved, but solvent type selection is limited

Engineering Contradiction:
ImprovedispersibilityVSAvoidsolvent type selection
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent employs a surfactant system that provides universal dispersibility across multiple solvent types. The surfactant can effectively disperse cuprous oxide particles in various solvents including water, alcohols, and organic solvents, making the system versatile and adaptable to different application requirements without being restricted to specific solvent types as in microemulsion methods.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 facilitates a simpler synthesis process, maintains high dispersibility and antibacterial performance even at increased cuprous oxide concentrations, and ensures transparency and effective antibacterial/antiviral properties in the coating film.

Implementation Method 1

20 to 100 parts by mass of a phosphate ester-based anionic surfactant per 100 parts by mass of the cuprous oxide particles

Methodology Applied
Scientific EffectSurfactant adsorption: Adsorption

Implementation Method 2

phosphate ester-based anionic surfactant

Methodology Applied
Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Implementation Method 3

500 to 10000 parts by mass of an organic solvent per 100 parts by mass of the cuprous oxide particles

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 4

the average secondary particle diameter being measured by dynamic light scattering using cumulant analysis

Methodology Applied
Scientific EffectDynamic light scattering:

Implementation Method 5

dynamic light scattering

Methodology Applied
Scientific EffectBrownian motion: Brownian Motion

Data Source

PatentUS9414585B2Cuprous oxide particle dispersion liquid, coating agent composition, and antibacterial/antiviral member
Publication Date: 2016.08.16 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A cuprous oxide particle dispersion liquid includes: cuprous oxide particles; 20 to 100 parts by mass of a phosphate ester-based anionic surfactant per 100 parts by mass of the cuprous oxide particles; and 500 to 10000 parts by mass of an organic solvent per 100 parts by mass of the cuprous oxide particles. The cuprous oxide particles have an average primary particle diameter of 2 nm to 80 nm and have an average secondary particle diameter of 50 nm to 150 nm, the average secondary particle diameter being measured by dynamic light scattering using cumulant analysis. A coating agent composition includes the cuprous oxide particle dispersion liquid and a binder resin, wherein the cuprous oxide particles are contained in a range from 0.1 to 50 parts by mass in 100 parts by mass of a non-volatile matter content of the coating agent composition. An antibacterial/antiviral member includes a substrate and a coating film formed on the substrate and containing the coating agent composition.