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The Guide to Woven and Non-Woven Cleanroom Wipes – Usage, Protocol, and ISO Class Applications

Cleanroom wipes differ by application, cleanliness, materials, and essential properties. This post addresses cleanroom and industrial requirements such as ISO classes, procedures, protocol, ESD-safe properties and use cases for manufacturing. The cleanroom wipe is historically the most effective and commonly used tool for the removal of contaminants, particulate, and residual material in critical manufacturing and pharmaceutical compounding environments. Highly absorbent, low lint materials enable tight control of moisture, solvents, and spills for cleaning of cleanroom surfaces, walls, machinery, fixtures, transport carts, tools, and other production materials.

What’s the Difference Between a Woven and Non-Woven Cleanroom Wipe?

What's a Nonwoven Wipe?

Nonwoven fabrics are broadly defined as a sheet or web structure bonded together by entangling fiber or filaments (or by perforating films) mechanically, thermally or chemically. Post-treatment and unique construction characteristics provide some potentially beneficial outcomes, such as a porosity that enables gas sterilization. Nonwoven wipes offer an economical choice, as the manufacturing process does not require laundering. Cellulose and synthetic blended hybrids provide additional absorbency for spill cleanup and removal of thick liquids. Generally, nonwoven wipes are used in cleanrooms no cleaner than ISO Class 6 or above.

Hydroentangled blend of 45% polyester / 55% cellulose

Nonwoven Polycellulose Wipes Made with a hydroentangled blend of 45% polyester / 55% cellulose; providing economical performance & purity. This creates a strong, clean, and very absorbent wipe for liquid removal or lint free wiping in controlled areas.

What's a Knit (Woven) Cleanroom Wipe?

Woven wipes, also known as knitted wipes, assist contamination control in critical environments. Woven fabrics are the highest quality cleanroom wipes on the market today. Low levels of NVRs and superb particle removal is ideal for critical class environments. Unlike nonwoven fabrics, woven cleanroom fabrics are formed by knitting or looping monofilament, continuous polyesters or other synthetics. The outcome is cleanroom wiper with great tensile strength that will not shed. The lowest amount of linting and particulate generation yields compliance for ISO Class 3 and upwards.

What Are the Advantages of Woven Polyester Cleanroom Wipes?

100% Continuous Filament Polyester — What is a Knitted Polyester Cleanroom Wipe?

Polyester is a synthetic petroleum-based fiber. Monofilament or continuous polyester cleanroom wipers is the cleanest wiping material available. Monofilament structure ensures a very strong and durable material. Naturally, polyester absorbs solvents but not aqueous solutions; a finish treatment is commonly applied to improve sorbent properties.

Laundered polyester knit cleanroom wipes undergo a laundering process using ultra-filtered water at 0.45 micron before HEPA filtered moisture removal. Packaging and sealing under an ISO class 4 laminar flow workstation with a hermetically sealed (air tight) package ensures cleanliness and traceability before final inspection. Cleanroom processing and laundering ensures low particle shed, consistent quality, and favorable outcomes in class 3-5 cleanrooms. The wipe will also not shrink or change shape. Compatibility with cleaning solvents such as IPA and autoclave ready temperature ratings enables use for the most critical cleanroom environments.

Double Knitted Polyester Cleanroom Wipes

Double-knitted monofilament polyester creates a super soft fabric for increased durability and particle retention. The material is knitted and interlaced twice in a cross pattern for the strongest possible outcome. Double knits yield a cross-hatched texture which increase surface area and capture more particles than traditional polyester knit wipes. Tightly knitted designs reduce surface catches, unraveling, and breakage of yarn filaments that generate particulate.

Polyester Double Knit Wipes The CleanPro® Double Knit Pro 1 9″ x 9″ wipe is composed of 100% double-knit polyester. They are processed and double bagged in an ISO Class 4 cleanroom environment.

Polyester/Nylon Cleanroom Wipes

Polyester/nylon wipes for cleanroom and industrial applications generally feature a mix of between 25-30% nylon and 70-75% polyester. The result is a very soft fabric which will not scratch sensitive devices yet is extremely effective in trapping micro-contaminants without re-contaminating the surface.

Polyester/Cellulose or Polycellulose Cleanroom Wipes

Polyester cellulose wipes, also known as polycellulose wipes, generally feature a 55/45 mix of cellulose and polyester which is hydroentangled for a chemically pure wipedown without binders, starches, or thermal bonding. Cellulose aids electrostatic dissipation as a naturally ESD-forward material, which is commonly used where liquid retention is important.

What are the Advantages of Cellulose Blended Wipes?

The mix of cellulose and polyester may vary as the majority depending on the need of absorbance versus less lint. Cellulose is more absorbent, while polyester is less linting. Polycellulose blended wipes are one of the most popular cleanroom wipes for general wipedown and spill control in ISO Class 6 and above cleanrooms. Biodegradable and naturally ESD friendly, polycellulose provides one of the most economical cleanroom wiper options because it’s easy to produce and process. Price, chemical resistance, and high absorbency are among its most desired features.

Types of Nonwoven Cleanroom Wipes

Nonwoven fabrics are flat, porous sheet made from separate fibers or from molten plastic. Conversion from fiber to yarn for weaving or knitting is unnecessary in the manufacturing process. Nonwovens have a limited lifespan, and are generally used for one time wipe down and then discarded. Non-woven materials support a number of applications where a unique combination of characteristics is achieved by a combination of fiber and additives. An advantage of nonwoven fabrics is the capability for very wide widths, and an overall lower cost of manufacturing. Three types of manufacturing processes distinguish most nonwoven cleanroom wipe designs:

Meltblown wipe construction requires the thermal bonding of ultra-fine polypropylene fibers.

Hydroentangled wipe construction requires high pressure jets which entangle and clean the fibers. The process forgoes binders or additives which yields the lowest possible residual remnants or manufacturing bi-products like binders, ions, or extraneous fibers.

Spunlaced wiper construction applies low impact water jet energy to a fabric web and vacuum dewatering that results in spunlaced fabric. Low particle counts when wet or dry renders spunlaced wipers particularly useful for cleanroom wipe down.

Cotton Cleanroom Wipes

Cotton provides a thermally stable, solvent resistant, and static dissipative wiper within an ISO Class 7 or above cleanrooms or clean spaces. Its ability to absorb up to 6x as much liquid as other wipes is ideal for handling aqueous or solvent solutions. While cotton is not recommended for critical particle control, it enables high heat cleaning for enclosed injection molding, electronics, or other enclosed high temperature machinery. Cotton enables elevated temperature applications, and food-safe contact due to natural construction which is biodegradable and sustainably sourced. The most delicate of common cleaning fabrics, cotton is uncommon where minimal shedding and tear resistance is paramount. Despite claims of cotton wipes that attain ISO Class 3 – ISO Class 5 compliance, our in-house experts agree that a cotton wipe should not be used in an ISO Class 6 cleanroom or cleaner.

Polypropylene Cleanroom Wipes

Polypropylene is an industrial-grade thermoplastic which when combined with minerals and other additives during the manufacturing process is malleable into synthetic papers and wipes. The result of meltblown entanglement process is a uniformly flat surface with exceptional particle removal characteristics. It has excellent compatibility with acids, bases, and solvents.

Microdenier or Microfiber Wipes for Cleanroom Applications?

Microdenier, interchangeably used with microfiber, is constructed of synthetic yarn, typically a bi-component polyester-nylon polymer, or 100% polyester polymer. Microfibers absorb up to 99.4% of microorganisms found on the surface compared to only 30% for wipers containing cellulose. Therefore, microfiber is ideal for cleaning nano-sized particles, removing fingerprints from screen displays, applying or removing liquid, or wiping a wet surface dry. Problematically, the intense absorption characteristics render a material that is difficult to clean, and also retains many of the additives, ions, particulate and NVR acquired during the manufacturing process. Fragile bicomponent filament construction, such as 70% polyester and 30% nylon challenges particle control because it’s more susceptible to tearing, breaking, and shedding. For cleanroom use, a 100% polyester microfiber yarn ensures a cleaner more consistent wipe due to tightly knit filament structure which exceeds the cohesiveness of the previous generation of microfiber materials.

Dry and Presaturated Cleanroom Wiper Materials and Construction

Presaturated Cleanroom Wipes

Local or large-surface disinfection of cleanrooms or clean spaces favors easy to grab, easy to apply, and evenly saturated solvent wipes. Simplified workstation and equipment wipedown provides a high level safety and procedural consistency. Presaturated wipes aid cleanliness in compounding pharmacies, pharmaceutical manufacturers, and hospitals because of the convenience and even dispersion of chemical solvents.

Use of Sterile Presaturated Cleanroom Wipes

Sterile presaturated wipes generally feature a meltblown polypropylene or knitted polyester fabric saturated with 70% IPA and 30% deionized water which is then gamma irradiated. Gamma irradiation and aseptic filtration ensure sterile outcomes during the manufacturing of sterile presaturated wipes. Sterile wipedown materials ensure the utmost cleanliness in critical drug compounding areas such as intravenous IV preparation or sterile packaging. Resealable pouches and tamper-evident labels ensure integrity of the product upon final delivery.

Sterile Cleanroom Wipes

Pharmaceutical, Compounding or Medical Device Packaging

USP 797 and USP 800 compliant pharmacies, cGMP pharmaceutical compounding facilities, and medical device manufacturers require gamma irradiated cloths to maintain an aseptic environment. Sterile classification requires that biomedical and pharmaceutical products abstain from the presence of living organisms and also pyrogens. A pyrogen is a lipopolysaccharide from the cell wall of a gram-negative bacteria, which commonly grows in ultra-pure water. USP chapter 161 denotes acceptable limit of endotoxins or pyrogens with 0.5EU/mL for medical devices and 20 EU/device for products in direct contact with cardiovascular or lymphatic systems. The FDA specifies a limit of <1EU/wipe, 0.5 EU/mL for medical devices, or 20 EU/device for products that directly or indirectly contact the cardiovascular and lymphatic systems. Final delivery features triple or double-bagged packaging and a certificate of sterility.

Presaturated wipes are pre-wetted and saturated with 70% isopropyl alcohol (IPA) and deionized water (DI) filtered to 0.2 um. Each pouch, usually sold by the case with individual packs of 50 wipes, is labeled with a lot number for traceability and process accountability.

Sterile IPA Cleanroom Swab Usage

70% IPA swabs are commercially available in individual foil-sealed packages. Application of IPA to entry points on bags and vials before opening curbs any preexisting contamination obtained during the transportation from its sterile packaging center. Sterile packaging designed for sterile delivery and opening does not require disinfection on site when used properly. IPA wetted gauze or other particle-generating material is not effective in this process, due to potential introduction of physical particulate within CSPs.

Cleanroom wipes and swabs halt particle shed and contaminate spread during the wipedown process of ISO class cleanrooms. The use of cleanroom wipes increases with output and degrees of cleanliness with frequency define by multiple factors, including: The beginning of a production shift, before each segment of the manufacturing or production process, after spills, or when surface contamination is known or suspected. For pharmaceutical compounding, wipedown is conducted at intervals of no longer than 30 minutes while activities remain ongoing.

The Case For Cleanroom Wiper Dispensers

Wipe dispensers provide easy storage, easy access, and eliminate the waste and cross-contamination of holding too many wipes at a single time, therefore throughput is easily scaled. Pre-saturated 70% isopropyl wipes generate ideal outcomes during sanitary wipedown. It should be noted that isopropyl alcohol does not kill bacteria or fungal spores, which you can read about in further depth here.

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Contact: Allen Tang

Phone: +86 13632876247

Mailto: info@tlycleanroom.com

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