Antimicrobial Coating Composition With Uniform Up-Conversion Phosphors
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Solution Overview
Problem
Existing antimicrobial coatings using up-conversion phosphors suffer from inhomogeneous particle size distribution and low emission intensity, which affects their effectiveness and compatibility with coating matrices.
Innovation Solution
A curable composition incorporating up-conversion phosphors with a homogeneous particle size distribution and increased emission intensity, prepared using a halogen-containing flux, specifically ammonium, alkali metal, or alkaline earth metal halides, and doped with praseodymium and gadolinium, is used to create coatings with enhanced antimicrobial properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If up-conversion phosphors are incorporated into antimicrobial coatings, then antimicrobial effectiveness is improved, but particle size distribution becomes inhomogeneous
Solution Approach 1:
The patent modifies the synthesis parameters by introducing a flux system with specific metal halides (NaCl, KCl, CaCl2) and controlling calcination temperature (900-1000°C) and time (6-12 hours) to achieve homogeneous particle size distribution while maintaining up-conversion properties for antimicrobial effectiveness
Solution Approach 2:
The patent uses a flux as an intermediary substance during synthesis that mediates between the reactants and facilitates the formation of uniform phosphor particles. The flux system acts as a medium that controls particle growth and prevents aggregation, resolving the contradiction between effectiveness and uniformity
2Reliability
If up-conversion phosphors are used in coatings, then antimicrobial action is achieved, but emission intensity is low
Solution Approach 1:
The patent optimizes emission intensity by adjusting synthesis parameters including increasing calcination temperature to 900-1000°C, extending calcination time to 6-12 hours, and optimizing the dopant concentration of Pr3+ (0.1-5.0 mol%) and Gd3+ (0.1-5.0 mol%) to enhance up-conversion efficiency and photon emission
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (Ca, Li, Pr, Gd, Na, K, Ca) with specific stoichiometric ratios in the formula Ca1-aSra1-2bLnbNabLi2SiO4, where the composite structure enhances emission intensity through synergistic effects of different dopants while maintaining antimicrobial functionality
3Reliability
If phosphors with improved emission intensity are produced, then antimicrobial effectiveness increases, but production complexity increases
Solution Approach 1:
The patent combines multiple synthesis steps into a single integrated calcination process where mixing, flux addition, and sintering are performed in one continuous operation at 900-1000°C for 6-12 hours, simplifying production while achieving the desired phosphor properties for effective antimicrobial coatings
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 composition achieves higher emission intensity and improved particle size homogeneity, resulting in more effective antimicrobial action against various pathogens, including bacteria, yeasts, and viruses, while maintaining coating appearance and stability.
Implementation Method 1
the exploitation of the 'up-conversion' effect is also known. This uses phosphor particles with which electromagnetic radiation having wavelengths above UV radiation, especially visible light or infrared radiation, can be converted to electromagnetic radiation having shorter wavelength
Data Source
AI summary
A curable composition for production of coatings having an antimicrobial property, contains at least one film-forming polymer, optionally at least one additive and/or at least one curing agent, and at least one up-conversion phosphor of the general formula (I): A1-x-y-zB*yB2SiO4:Ln1x,Ln2z. In the general formula (I), x=0.0001-0.0500; z=0.0000 or z=0.0001 to 0.3000 with the proviso that: y=x+z; A is selected from Mg, Ca, Sr and Ba; B is selected from Li, Na, K, Rb and Cs; B* is selected from Li, Na and K; and preferably B and B* are not the same. Additionally, Ln1 is selected from praseodymium (Pr), erbium (Er), and neodymium (Nd); and Ln2 is gadolinium (Gd). The phosphor has been prepared using at least one halogen-containing flux.