Microdenier Wipers in Critical Cleaning Applications
Products used in cleanroom environments often have their origins in the consumer market. Microdenier (or microfiber, the terms are used interchangeably) wipers are no different. These products were introduced in the early 1970s as artificial leather.
Microfiber material is currently used in a broad range of consumer applications including apparel, eye glass cleaning, furniture covering, and car detailing. Microdenier fabrics feel soft, are durable, and have the ability to wipe surfaces clean even without using a wetting agent.
Microdenier wipers are increasingly gaining acceptance for use in cleanroom environments because of their ability to perform well in critical cleaning applications.
What is Microdenier?
Microdenier fabrics are constructed differently compared to traditional fabrics. Microdenier fabrics are made from synthetic yarns, generally bi-component polyester-nylon polymers, or 100% polyester polymers. Many filaments are processed together to form a yarn that will eventually be formed into a fabric.
Effectiveness of Microdenier Wipers
In the 1990s, hospitals started to use microfiber materials in cleaning applications. Five independent university studies in hospital settings compared the use of microdenier cleaning materials to more traditional cotton cleaning materials. All five studies came to the same conclusion: microdenier materials are superior to the traditional wipers when applying cleaning solutions and drying surfaces. The high sorptive capacity of the microdenier wiper (the ability to hold liquids in the wiper) allows for even distribution of a cleaning solution on surfaces; the first part of the surface receives the same amount of liquid as the last part of the surface being cleaned.
Even more remarkably, when microfiber wipers were used in a drying application, they removed up to 99.4% of microorganisms found on the surface compared to 30% for wipers containing cellulose. These same properties make microfiber wipers effective for:
- Cleaning nano-sized particles (or nano-particles)
- Removing fingerprints and oils from PC monitors, TV or smart phone screens without leaving behind any streaks
- Applying and removing liquids such as disinfectant solutions from surfaces
- Wiping a wet surface dry, unlike most synthetic wipers
Cleanliness of microdenier wipers
In spite of their impressive performance in cleaning applications, microdenier wipers have traditionally proved difficult to clean. The same attributes that make a microfiber wiper effective at cleaning (tight construction pattern in the wiper and the increased filament surface area) also makes cleaning the wiper more challenging. The increased surface area of the filaments tends to retain the additives needed to manufacture the microfiber fabric.Traditionally, the surfactant level was increased to remove process additives; however, the extra surfactant is also captured in the fabric. The result is a wiper with elevated NVR (non-volatile residues), ions, and particulate burden. Further, the density of the microdenier fabric construction can make it difficult to obtain a consistently reproducible edge treatment, which can contribute to higher variability in particulate levels.
A key factor contributing to the traditionally lower levels of cleanliness of microdenier wipers is the use of a bi-component filament, commonly composed of 70% polyester and 30% nylon, although the blend ratio can vary. The two components are split during processing making for a lower DPF, but the resulting filaments are more fragile and, hence, more susceptible to further breakage. Filament splitting leads to higher particulate and fiber levels. Further, nylon is not compatible with the same chemicals as polyester which prevents the use of these bi-component microfiber wipers in some applications.
Conclusions
Microdenier wipers present several advantages in their ability to clean surfaces when dry, consistently apply cleaning solutions to surfaces, and effectively remove microbial contamination from surfaces. Vertex™ TX59 has all of these advantages in addition to being the cleanest and most consistent microdenier wiper ever produced.
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