As part of the industry’s effort to provide options that leverage currently developments in the sustainable biopolymers, there are currently efforts to develop a PLA (polylactic acid) nonwoven material that is targeted for disposable healthcare markets that offers an alternative to the current product solutions in a cost-effective and performance efficacious manner. The PLA nonwoven material would be capable of passing the relevant EN (such as EN13432), ISO (ISO 14855) and ASTM (D5526-94, and/or ASTM D6400, and/or ASTM D5338) biodegradability and biocompostability tests (or equivalents) while at the same time hit the relevant performance metrics.
The current industry focus is on the growing issue of global infection and the vital contribution of single-use nonwoven medical devices, such as gowns and drapes, in protecting against infection. Preventing infection is critical for reducing patient suffering and morbidity, protecting medical staff in the operating theater and minimizing post-operative costs caused by infections, such as Heath Care Associated Infection (HCAI) and Methicillin Resistant Staphylococcus Aureus (MRSA). I strongly believe that depending on the circumstance, the nonwoven material should either be a barrier or as an active mitigator of infectious pathogens.
There is market trending towards completely green and sustainable disposables given the main advantage of nonwovens is that they are used only once, on one patient or during one procedure and incinerated after use, avoiding the need for handling and dismissing the potential spread of contaminants. While conversations are still prevalent whether single-use disposable gowns can be more expensive than repeat-use garments (for an excellent discussion please see: www.ansellhealthcare.com/pdf/ceu/Operating_Room.pdf), the reality remains that if the product solution is cost-effective, actively mitigates the spread of hospital acquired infections and its cradle-to-grave lifecycle footprint is environmentally attractive, the value proposition of the nonwoven product becomes fairly unassailable. There is a continued move to disposable from laundered, as purchasers are very aware of the costs of readmittance to hospitals because of people going into the hospital and picking up an infectious disease, which coupled with the logistics burden of laundering, erodes the bottom-line of healthcare provider who are under considerable pressure to improve their financial health.
One attractive pathway to providing a cost-effective and performance oriented nonwoven product is utilizing spunblown technology rather than the conventional meltblown manufacturing method. It is a flexible one step process that involves polymer spinning and fiber bonding utilizing extrusion of low/high melt viscosity polymer to make cost-effective nonwoven fabrics. Spun-blown is a hybrid technology bridging the gap between meltblowing and spunbond processes, creating small fibers compared to spunbond but strong compared to meltblown fibers accommodating spunbond and meltblown polymer resins (MFR 5 – 2500 g/10 min).
Utilizing this technology, Biovation has been able to generate a material that is flexible, skin-soft and has the drape and the requisite robustness need for specific healthcare applications. Testing is showing solid results for the nonwoven material as a barrier material, demonstrating that a product solution that would be acceptable to the healthcare provider is possible. A key parameter, breathability, demonstrated moisture vapor permeability values (ASTM E 96) of 3980 g/m2/day (target > 1000 g/m2/day) exhibiting that the healthcare personnel can wear the gown for long duration with comfort.
The essential characteristic for all nonwoven product providers is not just to ensure the material is breathable but also can act as a barrier to pathogenic loading. Finally, if the material is breathable and provides a barrier, and then additionally actively mitigates the bacterial, viral and fungal pathogens, it enables the healthcare provider with a series of options not previously available.
For barrier properties, the nonwoven material has to incorporate a hydrophobic coating which does not impede the breathability characteristics but yet at the same time provide performance characteristic that allow the material to pass the required industry testing. The commercial market has a plethora of DWR (durable water repellent) coatings which are applied to prevent the fabric from absorbing water and becoming saturated when worn in wet conditions. However, DWR does have limitations (for an excellent discussion see: andrewskurka.com/2012/breathability-its-importance-mechanisms-and-limitations/).
One possibility, is the coating LiquiGlide that was invented at MIT and which differs from super hydrophobic coatings that have been developed thus far, which have a textured surface that forms a cushion of air that prevents liquids from clinging to it. The LiquiGlide coating does away with the layer of air and replaces it with another liquid. Super hydrophobic coating can be also be made from many different materials. The following are known possible bases for the coating:
• Manganese oxide polystyrene (MnO2/PS) nano-composite;
• Zinc oxide polystyrene (ZnO/PS) nano-composite;
• Precipitated calcium carbonate;
• Carbon nano-tube structures; and
• Silica nano-coating; silica-based gels remain the most economically viable option at present.
However, super hydrophobic coatings rely on a delicate micro or nano structure for their repellence and hence this structure is easily damaged by abrasion; creative advancements in this technology platform can resolve this identified weakness.
In terms of integrating antimicrobial agents that are infused to the fiber for efficacious mitigation of pathogen it is important to consider the myriad of possibilities that are available. These possibilities are cost-effective and efficacious manner (without affecting the drape, breathability and barrier properties) allows another level of protection for the healthcare provider and contributes to the economics of patient healthcare and safety. In the current marketplace, for example, there are some commercially available antimicrobial technologies that can potentially be used:
1. Silver or copper based; e.g Agion, AlphaSan, Nanosilver, Cupron
2. Cationic treatments; e.g. Aegis, Purista, Biosafe, BioShield
3. Other; e.g. Microban, Ultra-Fresh
It is interesting to note that the recent Ebola epidemic has bought to the forefront not only the challenges of personal protective equipment (healthcare providers only being able to wear them for 45 minutes, logistics burden of bleaching the materials as a washdown after use, etc.) but also the opportunities present to the nonwovens industry. Bleach, the only approved EPA disinfectant for washdown of personal protective wear, has a poor health and safety profile together with an unattractive environmental risk profile. If the above antimicrobial possibilities, in conjunction with options that are next-generation and have been commercialized for medical use, such as chlorhexidine, are implemented such that it does not affect any change in application rates or procedures as currently established by WHO and CDC and therefore no retraining of the staff while being cost-effective, the nonwovens industry can play a very needed role in global healthcare solutions. Such solutions would be deployable in short to mid-term achieving global impact and mitigating future outbreaks. The key here is the innovative approach that uniquely merges existing manufacturing know-how with current and next-generation antimicrobial/anti-viral chemistries with the traditional cost-effectivity of nonwoven materials.
The below table exhibits ANSI/AAMI PB 70:12 classification of barrier performance of surgical gowns, other protective apparel, surgical drapes and drape accessories and the values obtained by a representative nonwoven PLA material. The PLA material does have a proprietary hydrophobic coating and a silver based antimicrobial infused to the nonwoven fibers.
It is also important for nonwoven product providers that they consider themselves taking on the burden of obtaining FDA 510K registrations for their material positioning as a unique and differentiated product solution at equivalent cost-effective levels with a “green and sustainability” value proposition. Doing so decreases the validation and testing time cycle that is conducted by the end-customer and increases the value of service and information that is provided by the manufacturer.
Nonwovens have an incredibly important role to play in the healthcare sector when it comes to disposable products. With the new advances in polymer chemistry, leading edge coating formulations and available suite of antimicrobial products, having a nonwoven that is a breathable barrier coupled with active pathogen mitigating characteristic is well within reach.