Protection from microbes gives plastic products a longer life

Plastics, like other materials, are constantly exposed to the environment where they are located and, depending on the surrounding conditions, a broad array of microbes can exist on their surfaces. This can potentially lead to a range of problems, from unpleasant odours to deterioration, that affect the sustainability of both virgin and recycled plastics in products. Whatever the industry, incorporating built-in antimicrobial additives into plastics to help reduce the growth of microorganisms and odours is one way to offer long-lasting product protection and sustainability.
 
Plastics are everywhere in our lives and, due to their versatility, have replaced steel in cars, paper in packaging, and wood in furniture. Its revolutionary discovery has led to the development of diverse, flexible and cost-effective materials that have influenced fashion and style, and made previously unattainable products available to all, from everyday necessities to once-in-a-lifetime luxuries. The demand for plastics is therefore continuing to skyrocket. However, single-use, disposable plastics have a long, none too complimentary history, with a bad reputation for posing environmental threats, from being pervasive in landfills and causing toxic pollution, to contributing to global warming and natural resource depletion.
 
Consequently, pressures from governments and consumers to offer more environmentally friendly plastic solutions are forcing a rise in demand for more durable, reusable or recyclable plastic products that result in less waste. However, plastic surfaces can sometimes succumb to the build-up of bacteria, moulds and mildew, leaving unpleasant odours and an unattractive appearance. This problem is exacerbated by reusing plastics that may already have been affected by microorganisms, for example, in storage containers, bottles and packaging used for products such as food, drinks and cosmetics. If these surfaces are not properly washed and disinfected, substances such as food debris or shampoo can collect in cracks and hard-to-clean corners, creating a nutrient-rich source for microbes. It is an issue that is prevalent in many sectors where manufacturers employ recycled plastics in their products, from toys and shower or hospital curtains to interiors and exteriors in buildings, automobiles and planes, in a move towards sustainability.
 
The effects of microbes
High-touch products and surfaces – including consumer electronics, home appliances, textiles, medical carts and even airport security trays – contain plastic components that are intended to have a longer lifetime than other materials, but are still vulnerable to microbial growth. Synthetic polymers within these plastics effectively serve as nutrient sources that encourage the growth of microbes, and their structure makes it particularly susceptible to the penetration and accumulation of bacteria, mould and mildew. This is greatly influenced by factors such as temperature, humidity and moisture, and can lead to stains and smells, ultimately resulting in damaging, long-term consequences that include permanent loss of the plastic material and increased expenses for repair or replacement. Helping to prevent microbial growth within the plastics themselves is therefore a remarkably effective and comprehensive approach that can overcome even these challenges.
 
Achieving sustainability with thoughtful product development
Product design is at the forefront of worldwide sustainability initiatives. Some plastics contain high levels of plasticisers that act as a carbon-rich food source for microbes so, in line with sustainability agendas, plastic manufacturing has begun transitioning from using synthetic phthalate to plant-derived alternatives, which are often considered greener. However, plant-sourced plasticisers – such as epoxidised soybean oil (ESBO) found in some PVC food packaging – are especially vulnerable to the growth of microorganisms. This is one reason why, although adding antimicrobials to products has been on the radar for plastics compounders for some time, until recently there hasn’t been a real push to overcome the challenges associated with reworking formulations and meeting regulatory requirements. While we’d all love to be greener in our use and reuse of plastics, antimicrobial technologies and odour control solutions are becoming an expectation rather than a ‘nice to have’. These innovations are thought to be contributing to sustainable product development by helping to prevent microbial growth, which preserves quality and aesthetics, extends the product’s lifespan and reduces plastic waste.
 
Tried and tested technologies for plastics
Silver and zinc have long been used in many industries for their antimicrobial properties, as they are potent at low concentrations against bacteria, yeast, and moulds. These additives work at a cellular level, continually disrupting the growth and reproduction of microorganisms. More recently, silver- or zinc-based additives have been incorporated into a wide range of products – from food storage containers to washing machines – during manufacture to provide continuous antimicrobial protection.
 
These built-in antimicrobial solutions and coatings adhere to a surface and effectively act as a barrier to help reduce the growth of microbes, improving the overall cleanliness of products. Having the capability to incorporate the same technology into various formulations, without impacting the plastic’s properties, is an important step forward for the future of the compounding and additives industries, and a promising prospect for bringing odour control and antimicrobial technologies into the fight for sustainability. Powerful, ‘always on’ protection that does not wash off or wear away provides the perfect complement to routine cleaning with surface disinfection products, ensuring products – especially those containing recycled plastics – can stay clean, smell fresh, and last longer.
 
There are a few leading companies in the market offering proven antimicrobial additives for plastics, but it is important to partner with a well-established and trusted provider capable of offering tailored solutions to match exact material requirements. Selecting a specialist supplier – such as Microban International – that has invested a lot of time and effort to address this unmet need is crucial. In-depth knowledge of global regulatory requirements can also help manufacturers to navigate the complexities of biocidal regulations in various geographical markets. For example, it is crucial to select an antimicrobial solutions provider whose silver- or zinc-based formulas, for instance, are registered with the Environmental Protection Agency (EPA) in the US or notified with the Biocidal Products Regulation (BPR) in Europe.
 
There is a portfolio of approved chemistries on the market that can be formulated into polymer pellets, powders and liquids. These scientifically proven antimicrobial protections can be manufactured into a range of synthetic materials, including polypropylene, polystyrene, polyethylene, polyvinyl chloride, polycarbonate and acrylonitrile butadiene styrene. Specialized pellet-based masterbatches ensure that the technology can be seamlessly incorporated into injection moulding, extruded thermoplastic and thermosetting polymer production processes. There are also a variety of powder and liquid-based masterbatches for other processes, such as powder coating, roto-moulding and foaming.
 
The sustainability of plastics of the future
Plastics that are treated with antimicrobial technologies have longer term benefits and make products more attractive to all consumers, including those who focus on sustainability and are environmentally conscious. Built-in treatments in plastics provide enduring protection by slowing the growth of degrading microbes – such as moulds and mildews – keeping materials cleaner, reducing odours, and promoting longer product life. This reduces the expense and environmental costs associated with wastage and premature replacement of materials, ultimately helping to shape a greener planet. The main aim now is to implement these sustainable plastics to ensure these added living benefits across the globe.