Polyvinyl chloride (PVC) is one of the most abundant polymers; with about 40 million metric tons produced annually. The practical uses of PVC are almost unlimited, with the popular polymer used in application ranging from utility materials such as drainage pipes, to sterile applications such as medical devices.
However, this very practical plastic is not popular only for its high versatility, but also for its proclaimed inherent antimicrobial properties.
UK-based antimicrobial additives provider BioCote’s Technical Team took a closer look at why this property of PVC could be more complex than one might assume.
What is PVC?
PVC itself is a white, granular powder that can be melted at high temperatures and formed into shapes.
It is thermoplastic, which means that once it is shaped, it can be reheated and remoulded.
However, PVC will begin to decompose at around 135°C and can immediately discolour and become brittle if exposed to these processing temperatures without a heat stabiliser.
Hydrogen chloride: a by-product of PVC breakdown
An extremely potent acid called hydrogen chloride (HCl) can be released as a by-product when PVC breaks down.
Due to the high temperatures, it is expelled as a gas; a release which can also trigger further breakdown of PVC chains. Hydrogen chloride, however, can become trapped in between the PVC chains and eventually slowly release itself from the product over time.
Understanding how hydrochloric acid makes PVC antimicrobial
Because of the powerful biocidal nature of hydrochloric acid (HCl), PVC is recognised for having what are described as “inherent” antibacterial qualities. However, this is not entirely correct.
With this understanding, it can be seen that it is hydrochloric acid (HCl) that is antimicrobial; PVC is not.
This, unfortunately, is not a permanent feature of PVC. Over the time of use, the amount of released HCl gradually decreases to a level where it is no longer efficient in killing bacteria. As a result, there is nothing stopping microbes from flourishing on the product’s surface after this point.
This is why this “inherent” property can not be relied upon as a long term solution in a cleanroom facility.
It is hydrochloric acid that is antimicrobial; PVC is not
Integrating antimicrobial technology
BioCote is aware of many materials such as PVC off-gassing and producing biocidal HCl that can distort the results of antimicrobial tests. The HCl can hide issues contained within formulations and may hide that an antimicrobial additive is being deactivated by something.
Because of this, BioCote requests that materials such as PVC are “aged”. This procedure can reveal formulation problems in products that proved to be antimicrobial, but only for a short-term period.
“We at BioCote then work with such manufacturers to address these issues to guarantee successful long-term antimicrobial protection that our global client base has come to rely on,” the company states.
While by-products such as HCl cannot be avoided through polymer processing, it is important they are not ignored. If antimicrobials are being incorporated, it is crucial to make sure the technology is working efficiently and continuously.
BioCote requests that materials such as PVC are “aged”
At BioCote we take all the extra steps needed to provide our customers with data that can independently demonstrate that the antimicrobial technology is effective not only on the day it was manufactured into their product, but even up to 25 years.
It’s in the walls
This technology can be applied to construction materials designed for hygienic spaces. This can include wall cladding for pharmaceutical manufacturing, healthcare spaces, food production, and other controlled environments.
Benefiting from in-built antimicrobial technology, the antimicrobial PVC wall cladding panels from BioClad’s BioCote portfolio are designed to combat bacteria and other microbes to uphold a fully hygienic environment (*). Independent testing checks that these materials show continuous efficacy in reducing levels of bacteria such as MRSA, E. coli, Legionella, Salmonella, Aspergillus niger and mould by up to 99.99%.
The continuous aspect of reduction is what defines the “inherent” antimicrobial properties from the “aged” antimicrobial properties.
It is also thanks to the “continuous” aspect that BioClad adheres to the industry accreditations and is ISO 9001, 14001, 18001, CHAS & Constructionline accredited. Particular UK compliance also means that the NHS has previously given the solutions the NHS Supply Chain Innovation Award.
The BioCote-protected range includes wall and door protection, flooring, IPS units and the world’s first, proven antimicrobial PVC hygienic wall cladding. All are ideal for environments where hygiene is paramount.
(*) The antimicrobial properties do not protect users or others against bacteria, viruses, germs, or other disease organisms. This technology is not a substitute for good cleaning practices
