Testing the efficiency of Antimicrobial finish

The antimicrobial finish is imparted to the fabric or garment to eradicate the following problems during the usage of the material.

After finishing the material it should pass one of the or all the following tests as required by the customer.

Antimicrobial Finish – Tests

Finish type	Problem	Area of application
Material protection (rot proofing)- Long term	Loss of tensile strength in use. Loss of tensile strength during Storage	Tents, webbings, awnings Storage of all cellulosic goods
Material protection (rot proofing)- Short term	Loss of tensile strength	Cotton, Viscose, Flax, Jute and Wool fabrics, fibres and yarns left wet between processing
Aesthetic	Odour staining	Socks, underwear linings, Shower curtains
	Staining, odour	Storage of fibres, yarns and fabrics with high humidity (climate or storage)
	Staining	Storage of packaged non-cellulosic textiles under fluctuating temperature conditions
	Staining	All textiles left wet between processing
	Difficult to launder dust mites	Bedding, mattresses, carpets, upholstery
	Cross-infection	Protective clothing

Testing

Agar plate method

For bacteria this could be 18-24 hours at 37°C for fungi, 3-14 days at 28°C or upto 4 weeks for materials such as PVC coated fabrics. At the end of the incubation period samples are assessed either visually or by performance loss.

Soil burial test

The soil burial test is a relatively crude method for assessing anti-microbial finishes and is very severe. It is suitable for tents, tarpaulins and sandbags. Strips of the material under test are buried in prepared soil for 7, 14, 21or 28 days (or longer for plastics and coated fabrics) and after burial the samples are then tested for loss in tensile strength.

The soil burial test cannot be used for assessing aesthetic anti-microbial finishes but if the fungicide performs well in this test it will almost certainly perform well in less severe procedures.

Saturated atmosphere test

This method is suitable for assessing fabrics that will come into contact with airborne microorganisms but will not be in contact with the found.

Count test (Bacterial Challenge)

The previous test methods are all qualitative or at best semi-quantitative. In contrast, the count test is quantitative although its application is more limited.

Overall the need for anti-microbial and hygienic finishes looks set to continue for the foreseeable future. Improving performance and cost-effectiveness, while meeting environmental and toxicity requirements, will continue to challenge those working in this field.

Summary of test methods >> Read more...