Introduction to nonwovens technology

Nonwovens technology can be used to produce a wide range of products to meet a growing number of end applications.
There is evidence that the earliest method of turning fibers into fabric was felting, which used the flake structure of wool to firmly bind the fibers together. Some production technologies used in today’s nonwovens industry are based on this ancient method of forming fabrics, while other methods are the product of modern techniques developed to work with man-made materials. The origins of the modern nonwovens industry are unclear, but according to the Nonwovens Institute in Raleigh, North Carolina, the term “nonwovens” was first used in 1942, when webs of fibers were bonded together using adhesives to make fabrics.
In the decades since the term was coined, innovation has evolved into a dizzying array of technologies used to create products such as filtration, automotive, medical, hygiene, geotextiles, agricultural textiles, flooring and even clothing, to name a few. Here, Textile World provides information on some of the latest technologies available to nonwovens and product manufacturers.
German engineered nonwoven systems manufacturer DiloGroup offers a unique additive manufacturing process called 3D-Lofter, which was initially presented as a prototype at ITMA 2019. Essentially, the process uses a separate ribbon feed mechanism that operates similarly to a digital printer. The tape is fed into an aerodynamic web forming device, which allows additional fibers to be placed in a three-dimensional manner at specific locations on the flat needle felt. Added fibers can be placed to avoid thin areas and create stress points, change texture, build mountains or fill valleys in the base web, and even allow for the creation of colored or patterned designs in the resulting web. Dilo reports that this technology can save up to 30% of total fiber weight because only the required fibers are used after making a uniform flat needle felt. The resulting web can be densified and consolidated using needlepunching and/or thermal fusion. Applications include needle felt molded parts for automotive interiors, upholstery and mattresses, clothing and footwear, and colorfully patterned flooring.
DiloGroup also offers IsoFeed single card feeding technology – an aerodynamic system with several independent 33mm wide web forming units located across the entire working width of the cards. These devices allow the web or fiber strip to be dosed in the direction of travel, which is necessary to counteract changes in web quality. According to Dilo, IsoFeed can produce mesh mats using carding machines, increasing the CV value by approximately 40%. Other benefits of IsoFeed include savings in fiber intake when comparing conventional feeding and IsoFeed feeding at the same minimum weight; the paper web visually improves and becomes more uniform. Mats made with IsoFeed technology are suitable for feeding into carding machines, into airfoil forming units or can be used directly in the needling or thermal bonding processes.
The German company Oerlikon Noncloths offers comprehensive technologies for the production of nonwovens produced by melt extrusion, spunbond and airlaid. For melt extrusion products, Oerlikon offers separate one- and two-component equipment or plug-and-play options between upstream and downstream molding systems (such as spunbond systems) for the production of products with barrier layers or liquids. layers. Oerlikon Noncloths says its airlaid technology is well suited for the production of nonwovens made from cellulosic or cellulosic fibers. This process also allows for homogeneous mixing of different raw materials and is of interest for environmentally friendly processing.
Oerlikon Nonwovens’ newest product is Procter & Gamble’s (P&G) patented PHANTOM technology. Teknoweb Materials, Oerlikon’s hygiene and wipes partner, has an exclusive license from P&G to distribute the technology worldwide. Developed by P&G for hybrid nonwovens, Phantom combines airlaid and spin-coating technologies to produce wet and dry wipes. According to Oerlikon Non Wovens, the two processes are combined into one step that combines cellulosic fibers, long fibers including cotton, and possibly man-made fiber powders. Hydroweaving means there is no need to dry the nonwoven material, resulting in cost savings. The process can be customized to optimize desired product properties, including softness, strength, dirt absorption and liquid absorption. Phantom technology is ideal for the production of wet wipes and can also be used in products with an absorbent core, such as diapers.
Austria-based ANDRITZ Nonwovens says its core capabilities are in the production of dry-laid and wet-laid nonwovens, spunbond, spunlace, needlepunched nonwovens, including converting and calendering.
ANDRITZ provides technologies for the production of biodegradable environmentally friendly nonwovens, including the Wetlace™ and Wetlace CP spunlace lines. The production line is capable of processing wood pulp, chopped cellulose fiber, rayon, cotton, hemp, bamboo and flax without the use of any chemical additives. The company offers dedicated testing at its Center of Excellence in Montbonneau, France, which recently updated its innovative cellulose application system for the production of carded cellulose wipes.
ANDRITZ’s latest technology in biodegradable wiper nonwovens is neXline Wetlace CP technology. This innovation combines two molding technologies (on-line dry and wet lay) with hydrobonding. According to the company, natural fibers such as viscose or cellulose can be seamlessly recycled to produce fully biodegradable carded cellulose wipes that are high-performing and cost-effective.
The recent acquisition of France’s Laroche Sas adds additional dry fiber processing technologies to ANDRITZ’s product portfolio, including opening, blending, dosing, air laying, textile waste processing and hemp debarking. The acquisition adds value to the waste recycling industry by providing complete recycling lines for municipal and industrial waste that can be processed into fibers for re-spinning and end-use nonwovens. Within the ANDRITZ Group, the company is now ANDRITZ Laroche Sas.
In the United States, Andritz Laroche is represented by Allertex of America Ltd., Cornelius, North Carolina. Jason Johnson, director of technical sales and business development at Allertex, said LaRoche’s technology is ideal for the booming hemp fiber market in the United States. “We are currently seeing tremendous interest in debarking, cotton processing and processing of hemp fibers into nonwovens for building materials, tissues, automotive, furniture and composites,” said Johnson. “Combined with the discovery of Laroche, hybrid and air-laid technologies , as well as Schott technologies.” And Thermofix technology from Meissner: the sky’s the limit!”
The Thermofix-TFE double belt flat lamination press from Schott & Meissner Maschinen- & Anlagenbau GmbH in Germany uses a combination of contact heat and pressure. The processed product passes through the machine between two Teflon-coated conveyor belts. After heating, the material passes through one or more calibrated pressure rollers into a cooling zone to thermally harden the material. Thermofix-TFE is suitable for fabrics such as outerwear, reflective stripes, artificial leather, furniture, glass mats, filters and membranes. Thermofix is ​​available in two models and three different sizes for different capacities.
Allertex specializes in processing and nonwovens technologies, including opening and blending, web forming, gluing, finishing, hemp fiber processing and lamination from various companies.
As demand for high-quality disposable cleaning wipes continues to grow, German company Truetzschler Noncloths has launched a carded pulp (CP) solution that uses AquaJet spunlace technology to produce environmentally friendly wipes at a more economical price. In 2013–2014, Trützschler and its partner Voith GmbH & Co. KG from Germany brought to market the environmentally friendly WLS wet/molded installation process. The WLS line uses a cellulosic blend of plantation wood pulp and short lyocell or rayon fibers that is dispersed in water and then wet laid and hydroentangled.
The latest CP developments from Truetzschler Noncloths take the WLS concept one step further by combining wet-laid cellulose-based fabrics with carded fabrics made from longer viscose or lyocell fibers. Wet laid sizing gives the nonwoven material the necessary absorbency and additional bulk, and the fabric increases softness and strength when wet. AquaJet’s high-pressure water jets bond the two layers into a functional non-woven fabric.
The CP line is equipped with a high-speed NCT card machine between a Voith HydroFormer wet web forming machine and an AquaJet. This configuration is very flexible: you can dispense with a card and use only HydroFormer and AquaJet to produce WLS nonwovens; The wet lay-up process can be omitted to produce classic carded spunlace nonwovens; or you can use HydroFormer, NCT Card and AquaJet. used to produce double-layer CP nonwovens.
According to Truetzschler Noncloths, its Polish customer Ecowipes has seen high demand for nonwovens produced on the CP line installed in fall 2020.
The German company Reifenhäuser Reicofil GmbH & Co. KG specializes in spunbond, meltblown and lamination lines and is a business unit of Reifenhäuser GmbH & Co. KG, providing environmentally friendly options for the production of nonwovens. According to the company, its Reicofil line can recycle up to 90% of polyethylene terephthalate (PET) from household waste for industrial applications. The company also provides technology to produce hygiene products using environmentally friendly materials, such as bio-based diapers.
In addition, Reifenhäuser Reicofil also offers solutions for medical protective equipment such as masks. The company recognizes that these applications require 100% reliable fabrics and provides highly reliable equipment to produce nonwovens with filtration efficiency up to 99%, meeting N99/FFP3 standards. Shawmut Corp., based in West Bridgewater, Massachusetts, recently purchased approximately 60 tons of specialized precision melt blowing equipment from Reifenhauser Reicofil for its new health and safety division (see “Shawmut: Investing in the Future of Advanced Materials “, TW, that’s a question).
“For applications in the hygiene, medical and industrial sectors, we regularly set standards in performance and quality of the final products,” says Markus Müller, Sales Director at Reifenhäuser Reicofil. “In addition, we offer our customers the opportunity to produce environmentally friendly nonwovens from bio-based raw materials or recycled materials. We help our customers take advantage of the opportunities presented by the global transition to sustainable development, in other words: the next generation of nonwovens.”
The German company Reifenhäuser Enka Tecnica specializes in specially designed interchangeable intelligent spinning mandrels, spin boxes and dies that are compatible with any existing spunbond or meltblown production line. Its functionality allows manufacturers to upgrade existing production lines and enter new markets, including hygiene, medical or filtration. Enka Tecnica reports that high-quality nozzle tips and capillary tubes ensure consistent product quality and precision. Its meltblown spinning mandrel also features an optimized sustainable energy concept to reduce warm-up times and increase heat output. “Our main goal is the satisfaction and success of our customers,” says Wilfried Schiffer, Managing Director of Reifenhäuser Enka Tecnica. “That’s why personal relationships with our customers are just as important to us as the timely delivery of high-quality products. Long-term cooperation based on trust is more important to us than quick profits.”
Reifenhäuser Reicofil and Reifenhäuser Enka Tecnica are represented in the United States by Fi-Tech Inc., Midlothian, Virginia.
The Swiss company Graf + Cie., part of the Rieter Components business group, is a manufacturer of card coverings for flat cards and roller cards. For the production of nonwovens, Graf offers Hipro metallized cardboard garments. Graf says the innovative geometry used in the design can increase productivity in nonwovens production by up to 10% compared to traditional clothing. According to Graf, the front of the Hipro teeth has a specially designed projection that increases fiber retention. Optimized web transport from the cylinder to the docker increases productivity by up to 10%, and fewer defects occur in the web due to precise fiber transport in and out of the cylinder.
Suitable for both high-performance and conventional cards, these carding coatings are available in a wide range of steel alloys and surface finishes so they can be tailored to the specific application and fiber being processed. Hipro carded garments are designed for all types of man-made fibers processed in the nonwovens industry and are compatible with a variety of rolls including work, take-off and cluster rolls. Graf reports that Hipro is well suited for applications in the hygiene, medical, automotive, filtration and flooring markets.
Over the past few years, the German company BRÜCKNER Trockentechnik GmbH & Co. KG has significantly expanded its nonwovens product portfolio. The company offers ovens and dryers for nonwovens, including:
In addition, Brückner’s nonwovens portfolio includes impregnation units, coating units, stockers, calenders, laminating calendars, cutting and winding machines. Brückner has a technical center at its headquarters in Leonberg, Germany, where testing can be carried out by customers. Brückner is represented in the United States by Fi-Tech.
The quality of water used in the spunlace manufacturing process is very important. The Italian company Idrosistem Srl specializes in water filtration systems for spunlace production lines that remove fibers from the water to avoid problems with the syringe and the quality of the finished product. The company’s latest product is designed to control bacteria in the water cycle of wipes production. This technology uses a chlorine dioxide water sterilization system to prevent toxic substances, in particular chloride and bromate products, from entering the produced water. Idrosistem reports that the effectiveness of the sterilization system is independent of water pH and achieves the minimum required bacterial control in colony forming units per millimeter (CFU/ml). According to the company, the system is also a potent algicidal, bactericidal, virucidal and sporicidal agent. Idrosistem is represented in the USA by Fi-Tech.
The German company Saueressig Surfaces, owned by Matthews International Corp., is a renowned designer and manufacturer of embossing sleeves and rolls for decorative spunbonds and thermally bonded nonwovens. The company uses the latest laser engraving methods, as well as advanced moire technology. Hardened rollers, microporous housings, base and structural baffles enhance customization options. Recent developments include new 3D embossing and offline perforation capabilities using high-precision heated rollers with complex and precise engraving patterns, or the in-line use of nickel sleeves in the spunlace process. These developments allow the creation of structures with three-dimensional effects, higher tensile strength and elasticity, and high air/liquid permeability. Saueressig can also produce 3D samples (including substrate, engraving pattern, density and color) so customers can develop the best solution for their final product.
Nonwovens are non-traditional materials, and traditional cutting and sewing methods may not be the most efficient way to produce a final product using nonwovens. The pandemic outbreak and demand for personal protective equipment (PPE) in particular have led to increased interest in ultrasonic technology, which uses high-frequency sound waves to heat and plasticize nonwoven materials made from man-made fibers.
Sonobond Ultrasonics, based in West Chester, Pa., says ultrasonic welding technology can quickly create strong sealing edges and provide barrier connections that meet regulatory requirements. High-quality gluing at these pressure points allows you to obtain a finished product without holes, glue seams, abrasions and delaminations. No threading is required, production is typically faster and productivity is higher.
Sonobond offers equipment for gluing, stitching, slitting, cutting and trimming and can often perform multiple functions on the same equipment in a single step. Sonobond’s SeamMaster® ultrasonic sewing machine is the company’s most popular technology. SeamMaster provides a continuous, patented rotation operation that produces strong, sealed, smooth and flexible seams. According to the company, the machine can be used in various assembly operations as it can perform multiple functions at the same time. For example, with the right tools, SeamMaster can quickly complete gluing, joining, and trimming operations. Sonobond says it’s four times faster than using a traditional sewing machine and ten times faster than using a bonding machine. The machine is also configured like a traditional sewing machine, so minimal operator training is required to operate the SeamMaster.
Applications of Sonobond technology in the medical nonwovens market include face masks, surgical gowns, disposable shoe covers, pillowcases and mattress covers, and lint-free wound dressings. Filtration products that can be manufactured using Sonobond’s ultrasonic technology include pleated HVAC and HEPA filters; air, liquid and gas filters; durable filter bags; and rags and rods to catch spills.
To help customers decide which technology is best suited for their application, Sonobond offers free ultrasonic bondability testing on customer nonwovens. The client is then able to review the results and understand the capabilities of the available products.
St. Louis-based Emerson offers Branson ultrasonic equipment that cuts, glues, seals or quilts man-made fiber nonwovens for medical and non-medical applications. One of the important advances the company is reporting is the ability of ultrasonic welders to monitor and record weld data in real time. This enhances customers’ quality control capabilities and enables continuous improvement, even on automated production lines.
Another recent development is the addition of fieldbus capabilities to the Branson DCX F ultrasonic welding system, allowing multiple welding systems to interface with each other and interface directly with programmable logic controllers. Fieldbus allows users to monitor the welding parameters of a single ultrasonic welder and monitor the status of a multi-machine production system via an electronic dashboard. In this way, users can optimize the production process and solve problems that arise.
Herrmann Ultrasonics Inc. of Bartlett, Illinois, is offering new ultrasonic technology for securing elastic cords in diapers. The company’s innovative process creates a tunnel between two layers of nonwoven material and guides the tensioned elastic through the tunnel. The fabric is then welded at specific joints, then cut and relaxed. The new consolidation process can be performed continuously or periodically. According to the company, the method simplifies the processing of elastic products, reduces the risk of breakage, increases the processing window and reduces production costs. Herrmann says it has successfully tested a number of material combinations, different elastic sizes and extensions, and different speeds.
“Our new process, which we call ‘binding’, will better support our customers in North America as they work to create softer, more environmentally friendly products,” said Uwe Peregi, president of Herrmann Ultrasonics Inc.
Herrmann has also updated its ULTRABOND ultrasonic generators with new controls that quickly trigger ultrasonic vibrations at the desired location rather than generating a continuous signal. With this update, format-specific tools such as the format anvil drum are no longer needed. Herrmann noted that overall equipment efficiency has improved because tooling costs have been reduced and the time required for format changes has been reduced. The combination of the Ultrabond generator signal with MICROGAP technology, which monitors the gap in the bonding area, provides multi-dimensional process monitoring to ensure consistent bond quality and direct feedback to the system.
All the latest innovations in nonwovens will definitely be showcased at the upcoming nonwovens exhibition INDEX™20 in October 2021. The show will also be available in a parallel virtual format for attendees who are unable to attend in person. For more information on INDEX, see this issue of the Global Triennial Nonwovens Exhibition, Moving Forward, TW.