Trial By Fire!

In the months following the global spread of and disruption caused by the Covid-19 virus, there emerged a steady spate of claims, press notes and scientific papers on ways and means to halt the contagion by adding protective layers on surfaces that were prone to frequent human touch. Dhananjay Sardeshpande pieced together these claims and looked up several scientific resources to find out what these ‘protective’ coatings are and how they work.

An anti-microbial laminate is a polymer-matrix composite of layers that have been treated with an anti-microbial agent. These fit into a variety of different applications, including flooring, countertops and wall partitions.

There is now a flood of products and varied claims about assisting in the halt of the spread of the Covid-19 virus, at least through contaminated surfaces open to human touch, including articles of day-to-day use such as wood-based furniture.

Canada-based Holsag Furniture recently said it would begin shipping its wood chairs to customers finished with a catalysed lacquer that includes an anti-microbial coating that prevents the growth of bacteria and some viruses.

Microban International, a leader in anti-microbial technologies, has teamed up with a leading textile manufacturer, to provide anti-microbial treatment of textiles for the hospitality industry in the UK, US, Canada and the European Union.

Nohara Japan has introduced Dr HardoLass coating, a patented technology, which stays on hard surfaces for up to 5 years. The coating has been tested against influenza Type-A virus and proven to be effective in suppressing the virus and bacteria, on contact.

A chemical engineering professor from Virginia Tech published a scientific paper on a surface coating that, when painted on common objects, de-activates SARS-CoV-2, the virus that causes Covid-19.  The idea is that when the droplets land on a solid object, the virus within the droplets will be inactivated.

Harvesting microbes

So what is an anti-microbial coating for furniture? People and businesses are more conscious than ever about hygiene and cleanliness. Furniture, especially wooden furniture, and upholstery can absorb micro-organisms such as bacteria, mold and other fungi. Keeping surfaces clean can be a constant struggle.

The ancient Egyptians discovered the remarkable cleansing power of anti-microbials more than 2,000 years ago by using specific molds and plant entrants to treat infections. Evidence of this has been found by scientists studying uncovered bones from ancient Egypt.

It was only in 1928 that the healing power of anti-microbials was discovered by modern scientists. It was the year Alexander Fleming discovered the immense healing power of a natural anti-microbial fungus known as penicillin. Thus, antibiotics were born.

Anti-microbial coatings control, destroy, or suppress the growth of micro-organisms and their negative effects such as odour, staining and deterioration. These anti-microbials do not all work the same. But most of them work by leaching or moving microbes from the surface on which they live.

A furniture finish that includes an anti-microbial formula prevents the growth of bacteria and some viruses. The US Environmental Protection Agency has assigned the anti-microbial toxicity rating to the safest category of chemicals. Therefore, they are certified and approved by the EPA for human use.

Working chemistry

An anti-bacterial agent destroys or inhibits the growth of bacteria cells. An anti-microbial destroys or inhibits the growth of micro-organisms or kills them outright.

Anti-bacterial technologies are effective against a broad spectrum of harmful bacteria, including E. coli and MRSA. They typically incorporate silver active ingredients, allowing for successful application in a wide variety of product types.

Anti-microbial technologies minimise the presence of bacteria, mold and fungi on surfaces for very long periods of time. The typical active ingredients in them include silver or zinc.

How do anti-microbial agents work? They disrupt the vital life processes of micro-organisms, eliminating microbial growth and preventing their reproduction.

They are most commonly applied during the manufacturing step itself to become a durable, built-in feature. Additives to prevent bacterial and fungal growth are also used to treat intermediate materials (adhesives, latex, pigments, etc.) while in transport and during storage.

This is even more important in warmer climates and during hot summer months, when these materials are prone to spoilage by microbes.

In anti-bacterial agents we can count soaps and detergents, which prevent the development of bacteria. Anti-microbial agents, such as alcohol-based hand sanitizers, prevent the spread of bacteria, fungi, parasites and some viruses.

This gives anti-microbial agents a broader scope of protection than that provided by anti-bacterial agents. In essence, anti-microbials can act as both an anti-bacterial and an anti-parasitic.

The 60-year-old Holsag primarily manufactures chairs from European beech at its 2,70,000-square-foot facility, to educational institutions and hospitality businesses throughout Canada and the US.

Its research & development and manufacturing teams worked with suppliers to add an anti-microbial formula to the catalysed lacquer finish. A coat of the lacquer is sprayed onto the chair frame. The anti-microbial formula has the same shelf life and warranty as the lacquer formula.

Laminates too

On a laminate surface, microbes can double in number every 20 minutes. This can result in staining, unpleasant odours and premature degradation that affects the durability, lifespan and hygiene of a laminate product. Once microbes have begun to proliferate on a laminate surface, constant cleaning is required to keep growth under control.

Recognising that the ability to clean constantly is unreasonable in most environments, Microban has developed a range of anti-microbial technologies for laminate surfaces.

An anti-microbial laminate is a polymer-matrix composite consisting of layers of materials that have been treated with an anti-microbial agent. These fit into a variety of different applications, including flooring, countertops, wall partitions, etc.

As a thermosetting material, high-pressure laminates (HPL) have a natural resistance to microbial proliferation. However, these hygienic properties have a limited lifespan and eventually wear off.

In addition to decreased efficacy over time, global biocidal regulations do not permit the marketing of any laminates as being anti-microbial unless they contain a registered biocide.

Microban anti-microbial laminate protection can be seamlessly introduced to HPL during the final resin bath of the impregnation process. The growing awareness of antibiotic resistance, combined with the regular inclusion of laminates in hygiene-critical spaces, has resulted in an increased demand for anti-microbial laminates in healthcare, consumer and commercial environments.

Other applications

Microban International is a global specialist in anti-microbial technologies that give protection against the growth of bacteria, mold, mildew and algae. Microban solutions on textiles and upholstery do not wash off or wear away.

Headquartered in North Carolina, USA, Microban’s latest ‘Protect-360°’ product line include mattress encasements and pillow protectors that are treated with Microban anti-microbial product protection and inhibit the growth of product damaging bacteria. Protect-360° products are water-proof, bedbug-proof, and have passed third-party testing for viral penetration protection.

A recent study revealed that 68% respondents said cleanliness in hotels has become extremely important to them over the last year. Over and 58% of respondents said they would be willing to pay more for a hotel room with products treated with anti-microbial protection.

Once an anti-microbial coating is bonded to a surface, it is ready for action. The microbe is punctured by the long molecular chain (sword). The positive/negative attraction of nitrogen draws the microbe further down the ‘sword’. When the cell membrane of the microbe comes in contact with positive charges, it is electrocuted and blown apart, accounting for a reliable ‘kill’.

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