Antimicrobial Textile Zinc Loading via Wash Solution to Prevent Loss

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Solution Overview

Problem

Conventional antimicrobial/antiviral articles experience a decline in antimicrobial efficacy due to zinc loss during wash cycles, as the laws of thermodynamics predict a mass transfer of zinc from the article to wash water, leading to reduced bioefficacy over multiple washes.

Innovation Solution

A wet treatment process involving a wash solution with a specific concentration of zinc, pH greater than 3.5, and a wash time greater than 10 seconds, which results in a washed article with a zinc content at least 10% greater than the initial content, demonstrating enhanced antimicrobial efficacy and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If zinc is incorporated into the polymer matrix of antimicrobial articles, then antimicrobial efficacy is improved and retained during washing, but zinc mass transfer to wash water occurs due to concentration gradient, leading to gradual loss of zinc and deterioration of bioefficacy over multiple wash cycles

Engineering Contradiction:

Improveantimicrobial efficacy retentionVSAvoidzinc loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary anti-action by pre-saturating the wash solution with zinc ions before the wash cycle begins. This creates a zinc reservoir in the wash water that prevents zinc leaching from the article, effectively counteracting the concentration gradient that would otherwise drive zinc loss. The wash solution is prepared with zinc salts (such as zinc sulfate, zinc chloride, or zinc nitrate) to establish a high initial zinc concentration that maintains equilibrium during washing.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful effect of zinc leaching into a beneficial effect by intentionally adding zinc to the wash solution. The zinc that would normally be lost from the article is instead replenished from the wash solution, transforming the leaching phenomenon from a loss mechanism into a maintenance or even enhancement mechanism for zinc content. This approach uses the same mass transfer principle to achieve the opposite effect.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of operation

If conventional washing is performed on zinc-containing antimicrobial articles, then cleaning function is achieved, but zinc content in the article decreases due to mass transfer to wash water

Engineering Contradiction:

Improvewashing functionVSAvoidzinc content

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent changes the chemical parameters of the wash solution by adjusting pH and adding zinc salts. The wash solution is maintained at a pH greater than 3.5 (preferably pH 4-9) and contains zinc salts at concentrations of 1-100 ppm. These parameter changes create conditions that prevent zinc leaching while maintaining effective cleaning. The pH adjustment is particularly important as it affects the solubility and stability of zinc compounds during washing.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If zinc concentration in wash solution is increased to prevent zinc loss, then zinc retention is improved, but cost and potential environmental impact increase

Engineering Contradiction:

Improvezinc retentionVSAvoidresource consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by using low concentrations of zinc salts in the wash solution (1-100 ppm, preferably 1-10 ppm). This is sufficient to prevent zinc leaching from the article without excessive zinc addition. The wash solution is typically reused for multiple wash cycles, further reducing zinc consumption. This approach achieves effective zinc retention while minimizing resource input and environmental impact.

Inventive Principle:

Principle #16Partial or excessive action

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 process significantly increases the zinc content in the article, maintaining or enhancing antimicrobial efficacy even after multiple wash cycles, with a washed article showing improved log reductions in bacteria and viruses, such as Klebsiella pneumonia and Escherichia coli, and achieving zinc retention over 100%.

Implementation Method 1

the laws of thermodynamics suggest that there may be some (slight) mass transfer of zinc from the article to wash water during wash a wash cycle

Methodology Applied

Scientific EffectMass transfer: Diffusion

Implementation Method 2

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS20230175197A1Am/AV metal loading via wet treatment

Publication Date: 2023.06.08 ASCEND PERFORMANCE MATERIALS OPERATIONS LLC

AI summary

A wet treatment process, the process comprising: adding an article comprising a polymer and an initial zinc content to a wash solution comprising solute and a wash solution zinc content; maintaining the article in the wash solution for a wash time greater than 10 seconds to yield a washed article comprising a washed zinc content; wherein the washed zinc content is greater than the initial zinc content; and wherein the washed article demonstrates a Klebsiella pneumonia log reduction greater than 0.90, as determined via ISO20743:2013 and/or an Escherichia coli log reduction greater than 1.5, as determined via ASTM E3160 (2018).