Are all cleaning wipes created equal?
23 May 2017
Wipes are used in almost every type of industry for a diverse array of cleaning tasks. Mike Jones, vice president at MicroCare Corp, explores the different types of wipes on the market
Technicians cannot do their jobs without the right tools and bringing the right wipes to the job is vitally important.
The most important characteristic in a wipe is the absorbency of the proposed wipe for the contamination. Absorption usually is expressed in mililiters of water (or alcohol) absorbed by a specific weight of material. Some wipes work well with solvents, for example, but will not absorb water. You need to get the right wipe for the contamination you have.
Once you have found a wipe that is suitable, then down-select based on the cleanliness (lint and particulate) you require. Cleanliness usually is inversely related to absorbency. The cleanest wipes may be less porous and unable to absorb as much contamination, while more absorbent materials may leave fibres or residues.
Packaging also is a factor with wipes. Most clean rooms require special “double-packaging” free of particulate. Another feature is static-dissipative wrapping which will not attract dust. These enhancements obviously add to the cost.
There are three categories of wiping materials used in flat wipes: non-woven, woven and knitted. Ordinary flat wipes are generally made from either paper or fabric. Paper is the most popular nonwoven product and usually is found in single-use disposables.
The cheapest paper wipes use glues (binders) to hold cellulose fibres in place. The most common binder is a water-based latex such as polyacrylate. These binders will dissolve when exposed to solvents, leaving adhesives, lint and fibres on the surfaces being cleaned. While cellulose wipes are cheap, most are insufficiently strong, clean and absorptive to handle anything but the simplest cleaning tasks.
In the middle price range are nonwovens made without cellulose. These use synthetic fibres such as polyester, polypropylene and rayon and, because the fibres are stronger than cellulose they will deliver better cleaning.
There also is a hybrid material called a “nonwoven fabric.” This material has the strength, softness and quality of a woven textile but is produced at the volumes, speeds and cost of a paper. These lint-free wipes often are selected for medical device and electronics manufacturing where residues must be strictly controlled.
Fabric wipes can be woven or knitted materials using a wide variety of fibres. The least expensive categories are rags, marketed as “reclaimed fabric.” These wipes are cut from recycled materials. A better choice is a “mill end” which will not have the seams or decoration of reclaimed fabric but can be loaded with permanent press chemicals, stain-resisters and dyes. Virgin “washed cheesecloth” makes a smooth and flexible material, and near the top of the quality pyramid is “washed diaper fabric” which is soft, strong and highly absorbent.
Many companies use swabs to clean tiny spaces. The materials of construction, plus size and configuration of the head and the handle are the primary factors to consider.
Cheap cotton make an inexpensive swab but leaves fibres behind. Reticulated foam makes a good swab for scrubbing but leaves particulate residues. The highest quality swabs are made from prewashed knitted fabric.
The better grades of swabs are glue-free and will not use adhesives to hold the swabs together. Adhesives may cause problems downstream in a manufacturing process. While absorbency is critical when selecting a swab, a unique issue is materials compatibility. The construction of the swab must be compatible with the cleaning application.
The presaturated wipe is the latest product to make significant market penetration in critical cleaning applications. A presaturated wipe made from nonwoven sythetic fabric brings the proper quality and quantity of solvent to the task, resulting in more consistent cleaning performance. A broad array of cleaning fluids, both water-based and solvent-based, have enabled manufacturers to tailor their presaturated wipes for different environments. Better packaging has allowed some companies to offer presaturated products with an unlimited shelf life.
The optimal cleaning fluids for presaturated wipes must be slow-drying mixtures of water with soaps, or alcohols, hydrocarbons or siloxanes. Stronger fluids, such as d-liomine, will attack the plastic tubs and fast-drying solvents will not deliver the required shelf life.
Whatever special requirements there may be, engineers can be comfortable that today’s wipe manufacturers will have the answer they need at a price that’s right.