One of the drivers of wipes innovation can be found in base sheet technology, specifically the nonwoven materials that are engineered to provide precise performance properties like strength, absorbency, fluid release and more. Fortunately for wipes manufacturers and consumers alike, there is a range of nonwoven materials available for different wipes applications, many of which are manufactured with high-speed, innovative and value-added processes.
This article will review some of the leading nonwoven base sheet technologies available today and will provide insight on how they can be used to deliver exceptional performance to wipes.
Meltblown nonwovens offer high wet strength and excellent compatibility with most wet wipe chemical formulations. Meltblown is available in both fine-fiber and dual-texture forms, depending on the type of end-use application. The microfibers in a meltblown nonwoven are extremely thin and tend to fall within diameters of one to five microns. These microfibers are randomly mixed to form a nonwoven web.
Fine-fiber meltblown nonwovens produced from multi-bank machines provide high absorbency and excellent metered fluid release properties. They are naturally oleophilic but can be treated to increase wettability. They are low-linting and contain no chemical binders. This mix of properties makes fine-fiber meltblown nonwovens an ideal base sheet for commercial and industrial-grade wiping applications including automotive/car care, hard surface cleaning and polishing, hard surface sanitizing and disinfecting and hand cleaning. Patterns can be incorporated into the sheet to provide extra strength and create different tactile hand feel.
Dual-texture meltblown nonwovens feature a smooth side and a “scrubby” side. The “scrubby” side fibers can be pigmented with various colors. As with fine-fiber meltblown, dual-texture meltblown can be engineered to provide high absorbency and excellent metered fluid release of desired wet wipe chemistries. They also are low in lint and contain no chemical binders. Dual-texture meltblowns are ideal for wipes used in hand cleaning/sanitizing and hard surface cleaning.
Interwoven Pulp/Polymer Material
A patented and proprietary material (Hydroknit Material), this nonwoven is manufactured using jets of high-pressure water to bond soft pulp fibers into a strong polypropylene base sheet without chemicals or adhesives. In the hydro-entangling process, the pulp fibers intertwine around each other and with the polypropylene base sheet. The result is a highly absorbent fabric that offers high wet strength.
This type of base sheet offers excellent wet durability, tear-resistance and a cloth-like appearance and feel. It is ideal for consumer/household wiping applications including hard surface cleaning; furniture cleaning and polishing; glass/lens wiping; as well as granite and stainless steel wiping.
Spunbond filaments are laid on a continuous belt and thermally point-bonded in a heated calendar to create a uniform web appearance without the need for binders.
Spunbond nonwovens offer high strength, softness and a cloth-like appearance. They are low in lint, durable and abrasion-resistant and are ideal for personal care wiping applications including insect wipes and other specialty hand and face wipes.
Coform base sheets are created through a proprietary process that combines short, wood pulp fibers with fine polypropylene meltblown fibers to create a homogenous sheet.
Coform nonwovens result in a thick, pillow-like sheet that is drapable and cloth-like. Because it is gentle to the skin, it’s perfect for personal care wipes, and its flexibility means it can easily get into corners and crevices for cleaning applications. Its wet strength integrity also makes it an ideal base sheet for wet wipes. The addition of texture to the sheet can improve its perceived cleaning performance and softness.
One of the advantages of coform nonwovens is their ability to take a variety of surface treatment options, such as embossing. Another is that by altering the ratios of hydrophilic pulp and hydrophobic polymer, a wide range of material properties can be yielded, including web stability, drapability, thickness and hand feel. In addition, by altering how the polymer is applied, various levels of strength and absorbency can be achieved.
Spunlace, or hydroentangling is a method of interlocking and entangling fibers around each other with high velocity streams of water. Spunlacing is generally produced from a web made of staple fibers formed through a dry formed, carded system, but small quantities of spunlace bonding are done on production lines that use a wetlaid forming process.
Manufacturers of spunlace nonwovens are using a variety of raw materials for the wipes market. These include cellulosic fibers, cotton and even layers of pulp. This technology is favored in wiping applications because it can offer strength, absorbency and a very textile-like feel and appearance.
Recent improvements to spunlace nonwovens have included improved flushability and dispersability, which has opened up new doors for wipes in flushable applications. Other areas of interest for spunlaced wipes include composite structures featuring layers of cellulose and pulp and 100% cotton wipes.
Airlaid is a nonwoven web forming process that disperses fibers into a fast-moving stream and condenses them onto a moving screen by means of a pressure vacuum. This process can also be produced with fluff or wood pulp and the web can be bonded with resin and/or thermal plastic resins dispersed within the pulp. The process yields a paper-like fabric that is more absorbent than paper. It also has a greater tear resistance and tensile strength when wet. These characteristics make them suitable for many absorbent applications including wipes.
Selecting the Right Nonwoven Base Sheet
When selecting a nonwoven base sheet for your wipe application, product managers and wipes manufacturers would be wise to evaluate the following:
• Quality: Does the nonwovens supplier offer consistent high quality nonwovens for conversion, or do they sell seconds or lower-grade material? In other words, would the supplier put their own name on the finished product with pride?
• Manufacturing capacity and accessibility: Does the nonwoven supplier have the capacity to meet changing demands based on seasonality or consumer trends? Is a claim of “Made in the USA” important to your customers?
• Sustainability: There’s a lot more to environmental sustainability than using recycled materials. Make sure you understand your supplier’s commitment to sustainability throughout the entire product lifecycle, from raw material sourcing and water/energy use to basis weight and in-use and disposal properties. In other words, which supplier can meet your nonwoven base sheet needs with the smallest environmental footprint?
• Marketing and Product Development: Does the nonwovens supplier have deep marketing capabilities and what it takes to help you win in the market? Do they themselves have experience developing and marketing nonwoven based finished products? If they do, chances are good that they intimately understand your needs and the needs of your customers.
At the end of the day, nonwovens suppliers should be ready and willing to work with you to meet your specific nonwovens needs, whether that means developing a new slit width, matching a specific base sheet to a new chemistry, and more.