Silver Zirconium Phosphate Antibacterial Agent Heat Resistance

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Solution Overview

Problem

Conventional silver-based inorganic antibacterial agents face challenges with heat resistance, chemical resistance, and resin coloring, and have limitations in processability, particularly when used in plastics.

Innovation Solution

A silver-based inorganic antibacterial agent is developed using a zirconium phosphate compound with hafnium, represented by the formula AgaMbZr(c+d)(PO4)3·nH2O, where M is an alkali metal ion, hydrogen ion, or ammonium ion, and c+d satisfies 1.75<(c+d)<2.25, enhancing heat and chemical resistance while minimizing resin coloring and improving processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional silver-based inorganic antibacterial agents are used, then antibacterial activity is achieved, but heat resistance and chemical resistance are insufficient

Engineering Contradiction:
Improveheat resistance and chemical resistanceVSAvoidantibacterial activity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material system consisting of silver ions incorporated into a zirconium phosphate matrix with specific crystal structure. The zirconium phosphate serves as a stable inorganic carrier that provides both heat/chemical resistance while releasing silver ions for antibacterial activity. This composite approach resolves the contradiction by combining the stability of zirconium phosphate with the biological activity of silver ions.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If conventional silver-based inorganic antibacterial agents are used, then antibacterial function is provided, but resin coloring occurs

Engineering Contradiction:
Improveantibacterial functionVSAvoidresin coloring
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent controls the crystal structure parameters of zirconium phosphate, specifically maintaining a P/Zr ratio within 1.5-2.0 and controlling particle size distribution. These parameter changes in the material structure prevent silver ion aggregation and reduce light absorption that causes coloring, while maintaining antibacterial functionality through controlled silver ion release.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional synthesis methods are used, then zirconium phosphate can be produced, but uniform mixing of raw materials is difficult and composition homogeneity is poor

Engineering Contradiction:
Improveproduction processVSAvoidcomposition homogeneity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs a sol-gel preliminary action where raw materials are pre-mixed in molecular level dispersion in a solution before forming the final zirconium phosphate structure. This preliminary homogeneous mixing at the molecular level ensures uniform composition in the final product, resolving the contradiction between ease of manufacture and composition homogeneity.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If calcining method is used for synthesis, then zirconium phosphate with controlled P/Zr ratio can be obtained, but pulverization and classification are required causing quality and productivity problems

Engineering Contradiction:
ImproveP/Zr ratio controlVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the synthesis parameters from high-temperature calcining to controlled precipitation or sol-gel methods at lower temperatures. By adjusting pH, temperature, and reaction time parameters, the method achieves both P/Zr ratio control and produces fine particles directly without requiring subsequent pulverization and classification, thus improving productivity while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

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 silver-based inorganic antibacterial agent exhibits superior antibacterial activity and prevents coloring, offering improved durability and processability compared to conventional agents, making it suitable for use in plastics and other applications.

Implementation Method 1

a compound wherein a silver ion is retained on a zirconium phosphate by ion exchange

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP2213173B1Silver-containing inorganic antibacterial
Publication Date: 2016.07.20 TOAGOSEI CO LTD

AI summary

The present invention is completed by finding that a silver ion-containing zirconium phosphate represented by the following formula (1) is excellent tin heat resistance and chemical resistance, low in resin coloring and excellent in processability.         AgaMbZrcHfd(PO4)3·nH2O     (1) wherein, in the formula (1), M is at least one ion selected from alkali metal ion, hydrogen ion and ammonium ion, a, b, c and d are positive numbers satisfying a+b+4(c+d)=9; c and d satisfy 1.75&lt;(c+d)&lt;2.25; and n is 0 or a positive number of not more than 2.