Silver-Copolymer Fabric Treatment for Low-pH Silver Retention

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Solution Overview

Problem

Existing methods face challenges in introducing biocidal silver into fabrics at low pH values without precipitation, making it difficult to create a fabric treatment resistant to biocide removal during laundering.

Innovation Solution

A composition comprising a silver ion complex with a copolymer, where the copolymer consists of 60-95% ethylenically unsaturated compounds with unsaturated or aromatic heterocyclic groups and 5-40% ethylene oxide units, is used to treat fabrics in an aqueous medium, maintaining stability at low pH values and ensuring effective silver retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a silver-polymer complex is used for fabric treatment, then biocidal silver can be introduced into the fabric, but the complex precipitates at low pH values making treatment difficult

Engineering Contradiction:
Improvebiocidal silver retentionVSAvoidcomplex stability at low pH
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the polymer by incorporating specific functional groups (carboxylic acids, organosulfuric acids, sulfonic acids, phosphonic acids, and esters comprising polymerized units of ethylene oxide) that maintain complex stability at low pH values. This parameter change in the polymer structure allows the silver complex to remain stable and soluble in acidic conditions where conventional silver-polymer complexes would precipitate.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If conventional silver introduction methods are used, then silver can be added to fabric, but the biocide is easily removed during laundering

Engineering Contradiction:
Improvesilver contentVSAvoidbiocide resistance to removal
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent creates a composite material system where silver ions are complexed with a specifically designed copolymer containing multiple functional groups. This composite structure enhances the binding affinity between silver and the fabric, making the biocidal silver resistant to removal during laundering while maintaining effective silver content on the fabric.

Inventive Principle:
Principle #40Composite materials

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 effectively introduces biocidal silver into fabrics at low pH, providing resistance to biocide removal during laundering and maintaining antimicrobial efficacy, as demonstrated by the silver-containing fabric's bacteriostatic activity against various bacteria.

Implementation Method 1

a complex of silver ion with a copolymer

Methodology Applied
Scientific EffectComplexation: Chemical Bonding

Implementation Method 2

introducing a biocidal silver material to a fabric... to provide a treated fabric resistant to removal of biocide by laundering

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentUS7927379B2Method for fabric treatment at low pH
Publication Date: 2011.04.19 NUTRITION & BIOSCIENCES USA 2 LLC

AI summary

A composition useful for treating fabrics. The composition contains a silver-containing copolymer having polymerized units of a monomer X which is an ethylenically unsaturated compound having a substituent group selected from an unsaturated or aromatic heterocyclic group having at least one nitrogen atom and polymerized units of a monomer Y which is an ethylenically unsaturated compound selected from carboxylic acids, organosulfuric acids, sulfonic acids, phosphonic acids and esters comprising polymerized units of ethylene oxide.