Coming clean: can nonwoven filters answer the call for better air & water quality?

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What do filtration customers want? Clean air. Clean water. How can roll goods producers meet those requirements? Through increased performance, technological innovation and improved cost efficiencies. This may sound straight-forward, but nonwovens producers in the filtration market are being challenged to offer cutting-edge technology for air, gas and liquid filtration applications while keeping costs down (in a world where costs keep going up). This may be a tall order, but it hasn't slowed activity in the filtration sector; in fact, more roll goods producers are entering this arena and bumping competition up to new heights.

Having more players in the game has meant two things: filter makers have more alternatives and filtration customers are demanding more from suppliers. Confirming an overall increase in strategic focus from the nonwovens supplier base was Christine Murray, director of filtration at PGI. "Nonwovens producers recognize the rapid dynamics occurring and recognize significant opportunities," she said.

Turkish producer Mogul Nonwovens has witnessed the growth trend going both ways. "On one side you have nonwovens manufacturers seeking product and market diversification," said Serkan Gogus, commercial director. "On the other side is the growing filtration market that's attracting them." As he sees it, in the end, if companies can't be innovative and compete in the same areas with the same type of products, the profitability and attractiveness of the market will decline.

For most producers, new market entrants aren't a major concern because products are specified and validated. This makes the cost of changing products expensive for the likely cost savings, especially when the margins and prices are already very competitive. Another boon has been the fact that the filtration market has typically been fragmented, with a range of raw materials and nonwovens technologies used across all segments.

Still, manufacturers can't rest on their laurels--quality and consistency is sure to continue to play a critical role in filter manufacturers' buying decisions. Marjorie Wilcox, marketing manager of DelStar Technologies Inc., pointed to the high level of sophistication involved in filter manufacturing and said that although high capacity producers have have been looking at the filtration market for a long time, filter manufacturers are more sophisticated than some other markets. "They will not move quickly, or just for a low price," she said.

Another consideration is the strong value component inherent in highly technical nonwoven filters. While this is an advantage for nonwovens, they still face the challenge of differentiating high value products from lower content alternatives and seeking new markets and applications for core technologies. Patrick Apfeld, vice president of marketing and business development at Lydall Performance Materials, characterized nonwoven filtration products in general as "loaded with technical content providing high levels of value to the filter producers and end users."

The higher technical content of specialized filtration products has raised the barriers to entry in filtration, and new market requirements are expected to continue to keep these barriers high. According to Jerome Barrillon, director of marketing, filtration for Ahlstrom, The field of roll good manufacturers is quite stable and most large names are present. Smaller players have a tendency to come and go based on demand in other industries," he said.

Economic Crisis?

As fuel and energy costs climb ever higher--and as the economy continues to worry consumers--nonwovens makers are keeping a watchful eye on just what the impact will be on the filtration market. While industry insiders certainly don't seem hopeful with regard to the current economic climate, they are staying surprisingly positive.

Barry Kellar, general manager and vice president of Freudenberg's North American filter business, said there are pros and cons to the current economic dilemma. The downside is that people are using filters for a longer period than they should in an attempt to squeeze out more time. The thought here is that 'time is money,' but actually people are choosing a short-term cost advantage rather than overall best value. Right now there is a lot of focus on short-term costs."

"On the other hand," he continued, "as energy costs go up, people look to protect their asset and use less energy to put air or liquid through a filter. They are after better efficiency and pressure drop."

Manufacturers agree that the key is to find a balance between short-term costs and energy costs. While there is a dynamic where consumers feel they can't afford to upgrade to a more expensive filter, what suppliers are banking on is the question of whether they can afford not to.

Unfortunately, what many customers are looking for--higher efficiency and better performance with a lower pressure drop in less expensive filters--are diametrically opposed requirements. To lower prices, producers need an economy of scale in manufacturing, which is not an option for many high-end filtration products. As is the case in many nonwovens sectors, the higher the level of innovation, the more difficult it is to keep costs down.

Despite current economic woes, the filtration sector has been steady for the first half of this year, but many companies report signs of an impending slow-down and expect the market to remain sluggish until the middle of next year or longer if conditions do not improve.

Danny Grover, president of needle-punch specialist Southern Felt, described both the industrial air and liquid filtration markets as challenging due to ever-increasing prices for raw materials and energy. "Turbulence in the economy is causing end users to rethink or put off purchases of filter products. The market is also demanding that any development work that goes on has value for the performance."

If the downside to offering premium products is cost, the upside is that such items are more immune to economic twists and turns than are commodity products. Although raw material prices have an impact on costs, in most cases filtration products have better yields and may be less affected than other, lower cost applications. The good news for nonwovens is that these products are less influenced by the purchasing decisions of consumers when the economy is down because they are olden viewed as essential.

Overall, the driving forces in the filtration sector are similar to other nonwovens segments--raw material prices, volatility in petroleum-based raw materials as well as reliable media supply are all key issues. "Filtration is not immune," remarked Ms. Murray of PGI.

She went on to describe the current position of suppliers in relation to customers' demands for better performance and lower prices as a tough balancing act but one that is achievable. "It is virtually impossible for suppliers to focus on innovation for improved performance without channeling the same amount of effort into optimizing I cost and overall system economics. The I entire marketplace has reached a new level of sophistication, and customers are demanding more performance at the same or lower price. With customized media designed for specific applications, we can meet this demand. With customers and suppliers working together to optimize the media, the processing and the filter systems, we can achieve that optimized balance for superior customer value."

Fiberweb employs a similar strategy, working with individual customers in innovative ways to mitigate some cost increases. "Our customers see the value in nonwovens," said Kim Rolman, director--Filtration at Fiberweb. "They continue to invest in the development and design of new applications utilizing nonwoven components."

Just how severe are recent raw material price increases? Severe. Keith Hayward, managing director of Monadnock Non-wovens, pointed to a 40% jump industry-wide over the last 12 months and described pricing as still volatile. "Price increases have changed the sweet point for cost benefit," he said. "In some cases it encourages lighter material to reduce costs at the expense of reduced efficiency. Often the low basis weight means that the impact of increased material costs are not so significant, but 40% increases do make a difference."

Up until the recent financial crisis, in general, filtration markets (with the exception of the automotive filter segment) had been holding up well. Today, things are different. "Raw material increases in synthetic and glass fiber, binder and almost every other component of filtration media are having a huge impact on filter media costs," observed Lydall's Mr. Apfeld.

Often, increasing energy costs drive companies to reduce the total energy consumption of filtration systems by designing longer-lasting, more efficient filters. Customers are increasingly concerned over pressure drop in air and liquid filters and are pushing for more environmentally-sensitive filters capable of re-use or recyclability. DelStar's Ms. Wilcox stated that, in response to demand for cleaner filters within the semiconductor industry, DelStar is investigating the use of high-purity resins, as well as improving the surface of its existing products, to create technically superior components for process chemical filters.

Another response from companies has been to reexamine the product development lifecycle while incorporating scrap material without negatively impacting the end product. H&V's director of business development Angelika Mayman said that escalating and volatile raw material prices are challenging filtration manufacturers to rein in costs and improve profitability. "While there has been some short-term moderation in energy costs, pulp prices remain high and certain raw materials such as specialty pulps, resins and synthetic fibers continue to increase."

Fine Things

A continuing trend in both air and liquid filtration is the need for finer particle size removal for reduced emissions, cleaner water and reduced energy costs. This has driven fine fiber, nanotechnology and membrane technologies into the forefront of filtration demand. New developments in fine fiber products are in turn spurring the need for higher performance support substrates and pre-filtration layers.

According to Lydall's Mr. Apfeld, the move toward finer fibers marks an important shift. "The market is being inundated with discussion about nanofiber, nanoparticles and nanotechnology; smaller and smaller particles require smaller and smaller fibers for capture."

With three key technologies in this field (fine-fiber meltblown, electrospun nanofibers and Disruptor nano-alumina), Ahlstrom is also seeing developments in nanotechnologies and the use of smaller fibers in the manufacturing of filter media. "The fibers are a recognized solution to address higher and higher requirements," said Mr. Barrillon. 'he trick is the industrialization of the process to manufacture products competitively."

Ms. Murray acknowledged a similar trend, explaining that PGI Filtration is responding with tailored designs to provide solutions through combinations of different raw materials, media design and processing technologies. "Historical scrim offerings are no longer adequate to meet the demands of the high-performance, fine-fiber composite structures, and prefiltration is becoming more essential for overall system efficiencies," she said.

Norafin also acknowledged the growing need for finer particle filtration and offers filter media with fine fibers, microfibers or even microsplit fibers that enable the filtration of finer particles. The company reaches high filtration efficiency by combining spunlace technology with fine micro or sub micro fibers.

The Future of Filtration

Looking ahead, industry experts expect to see a continued focus on improving air quality, more consumer awareness, a desire for higher efficiency products and a push for energy savings and green products. Additionally, Mr. Kellar of Freudenberg predicted increased diversity in applications and industries in the near-term future. "What I don't know is which industries will look for filtration, but I guarantee we'll see illters built into more products than we do today,"

Sandra VanWormer, president of DuPont's Hybrid Membrane venture, foresees education as a significant trend in air filtration in the next decade. "This includes raising the awareness and importance around good air quality and energy savings and how the proper air filtration system can achieve these goals efficiently, raising the standard of living and improving the sustainability of the planet." In addition, in targeted liquid filtration segments, the company is looking to significantly raise performance expectations in the 0.2 - 2.0 micron range of retention, creating a tailored, optimum balance of retention, flow and filter life for each end use segment.

Mr. Kellar of Freudenberg also acknowledged the need to continue to raise consumer awareness with regard to air quality. "People are smarter about air quality today but producers still wish they were more aware," he said. "For us, the biggest challenge in cabin air quality is awareness, not competition. Consumers now understand the need for better performing air filters in the home but many don't realize that the air in a car has a tunnel effect and is six times dirtier than outside. The bottom line is educating the consumer."

No doubt, the future of filtration will be shaped by several factors, one of which is a changing global financial setting. Many companies expect the most significant contributor to growth to be the emergence of the Chinese and Indian industrial and consumer economies. Increasing demand on energy supply across the globe is expected to spur development of lower pressure drop filtration technologies.

"In the established markets and in emerging markets such as China, we will see escalating efficiency requirements for existing applications as well as the adoption of filtration in new applications, particularly those related to 'quality of life," predicted Mr. Apfel of Lydall.

Overall, heightened global competition should be a prime driver for better efficiency and innovation in filtration products. As for China, it may turn out to be not only a competitor but a formidable market opportunity. According to Ahlstrom's Mr. Barrillon, the Asian region as a whole will continue to grow, but the local markets will consume a large part of the local production. "Many western industries are locating plants locally, mainly to serve the local markets rather than manufacture off-shore for western markets. Local quality by local competition will obviously improve to much higher levels and this will push the industry as a whole to continue to develop smarter and efficient solutions to stay ahead."

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photo courtesy of DelStar Technologies

By Ellen Wuagneux

Associate Editor

RELATED ARTICLE: A look at key players' recent activities in the filtration sector.

FREUDENBERG--In line with continued growth trends in the filtration sector, the world's largest nonwovens manufacturer, Freudenberg Group, plans to break out its filtration division into an independent business effective January 1, 2009. The new business will be known as Freudenberg Filtration Technologies, Limited Partnership and will continue to operate its North American headquarters in Hopkinsville, KY. (For more information, see Top of the News, page 12.)

Freudenberg provides finished cabin air filters for the automotive market as well as industrial air filters for commercial buildings and automotive painting facilities. In the area of liquid filtration, the company is active in membrane support technology and also offers filtration consultation services.

One interesting new product is an after-market laser printer filter for consumer use. "We continue to move forward with human protection efforts," said Mr. Kellar. "The micronAir Office filters have been introduced in Europe, and we are starting to talk to customers in the U.S. as well. In Europe, there is concern about laser toner cartridges emitting fine dust. The European health bodies are concerned about this and are beginning to question HP, Canon and other companies."

Another new micronAir product is a cabin air filter specifically designed for 18-wheel vehicles, where truckers spend extended periods of time. In Europe, Freudenberg's micronAir Pro line offers increased efficiency to capture fine dust particles such as diesel engine soot.

"We look at filters as more of a health device--striving for cleaner liquids or cleaner air," he added. For the past year-and-a-half, Freudenberg's air filtration products have been backed by Greenguard indoor air quality certification, a costly and rigorous program that certifies that the filtration products are healthy and not emitting contaminants. Greenguard (grenguard.org) is also tied in to the efforts of the Green Building Council (GBC).

DUPONT--At DuPont, efforts in air filtration center on HMT (hybrid membrane technology) nanofiber media for HVAC and dust collection markets, targeting high efficiencies such as MERV 13 to 16. For liquid filtration, DuPont targets HMT applications that require particle retention in the 0.2 to 2.0 micron range. An example would be slurries that require the filtration media to accomplish particle classification.

In the air filtration area, DuPont's HMT nanofiber synthetic media features a low pressure drop and corresponding improved energy usage as well as non-dissipating performance at high efficiency levels. For liquid filtration, DuPont HMT nanofiber media claim to have two to three times the flow rate of incumbent meltblown media at similar or better retention. Additionally, it provides performance similar to microfiberglass with media that have one-tenth the thickness and do not present concerns around particle shedding that is inherent to glass.

"As one would imagine, the trend in the air filtration market is toward lower energy usage," said Ms. VanWormer. "This is achieved with lower pressure drop across the media, the chief attribute of our HMT products. The market also has wanted to go to synthetic media for some time, but dissipating performance has slowed that move. We feel we have addressed the market's two major needs with our product line."

Ms. VanWormer also pointed to a driver to finer filtration in a broad range of liquid filtration applications. "This vector requires significantly increased surface area with traditional media. With the high flux of the DuPont HMT nanofiber media, at the same retention, the surface area can be significantly reduced, which lowers the cost of ownership on a 'cost per unit filtered' basis."

In addition to HMT, in early 2009 DuPont will launch a highly versatile new fine of liquid filtration media for large particle filtration. The new line is available for use in a variety of end use applications that use vacuum, pressure and gravity filtration. "Testing has demonstrated compatibility with a range of fluids, increased filtration efficiency and longer life, the benefits of which are a reduction in media cost, downtime inventory and waste disposal."

FIBERWEB--While the company's filtration business is best known for its Reemay brand of spunbond, Fiberweb supplies a full range of products to the filtration industry including meltblowns, drylaids, airlaids and composites. Although many of the developments Fiberweb devotes engineering resources to are customer-specific, the company is focused on driving nonwoven developments that deliver finer fibers, shaped fibers, more uniform structures and add further science into these structures by compounding additives into its resins. The bulk of this work is directed toward spunbond and meltblown nonwovens. Building on its Reemay technology, Fiberweb has unveiled a next-generation Reemay product line of fine-fiber spunbonds with mean fiber diameters of less than 2dpf.

AHSLTROM--Ahlstrom has spent the last several years boosting its filtration business through acquisition and capital investment. From traditional production processes to proprietary techniques, Ahlstrom's filtration solutions are designed to meet specific performance requirements. Among the company's key offerings is the Disruptor high-performance wetlaid filtration media that rivals UF and MF membrane filters in terms of retention and efficiency with flow rates of a nonwoven filter media. Potential filtration applications include: backup filter to UF and MF membranes, pre-filter to RO membranes, point-of-entry and point-of-use potable water and boiler feed water.

The latest version, Disruptor PAC, combines the benefits of powdered activated carbon with the existing performance of the regular Disruptor media, creating a complete filter media suited for a variety of uses.

For HVAC applications, Ahlstrom offers a range of products starting with nonwoven media in low to medium efficiency, complemented with microglass for high to ultra-high efficiency. The company targets the dust filtration sector with a range of felts from polyester to aramid, PPS and P84 for baghouse filtration applications. These products are now manufactured on a state-of-the-art line recently installed in South Carolina.

For fuel filtration, Ahlstrom sells media manufactured from a variety of fibers, which is designed to meet the performance requirements of today's most advanced engines. Ahlstrom sells high quality filter media for ultra low sulfur diesel and is currently developing solutions for biodiesel markets.

PGI--Another company with a broad base of filtration experience is PGI, which offers nonwoven media solutions for industrial air, HVAC, industrial liquid, pleat media, pre-filtration and performance substrates as well as support scrims for membrane, nanofiber and engineered composites. PGI Filtration provides customized filtration media, specifically designed with controlled pore size and excellent web uniformity for balanced filtration efficiency, cycle time/capacity and economics.

PGI's current focus is on developing filtration media that answer the industry's desire for higher performance with balanced filtration properties at competitive costs. "Customers are seeking filtration solutions to optimize their overall systems when it comes to reducing energy, increasing capital-equipment life and lowering total system costs," commented the company's Ms. Murray.

For industrial HVAC, PGI Filtration's UltraLoft Air was developed to meet higher demands in the mechanical MERV8 market. UltraLoft Air delivers MERV7 and MERV8 efficiencies with a balance of pressure drop, dust holding capacity and cost.

LYDALL--At Lydall, the focus is on providing innovative filtration media solutions for air, fluid power, industrial and life science applications through its global sales offices and production facilities in the U.S. and France. Lydall air filtration products include LydAirMG (micro-glass), LydAirMB (meltblown) and LydAirSC (synthetic composite) media. These products constitute the critical media component of clean-air systems for applications in clean-space, commercial, industrial and residential HVAC, power generation, industrial processes and protection/respiratory devices.

LyPore and activated carbon containing ActiPure media series address a variety of application needs including hydraulic filters, air-water and air-oil coalescing, industrial fluid processes, diesel filtration, biopharmaceutical pre- filtration and clarification, diagnostic tests and drinking water filtration.

HOLLINGSWORTH & VOSE--Hollingsworth & Vose (H&V) supplies a technically advanced engine and high efficiency filter media. Principal markets include: automotive, high efficiency ULPA and HEPA filter media as well as ASHRAE/indoor air quality, specialty liquid filtration and industrial filtration materials. The company has recently introduced its Nanoweb advanced synthetic nanofiber, which--when added to standard media--results in performance comparable to multi-layer laminates and microfiberglass-containing grades, while offering the caliper and pleating characteristics of a standard media. The product is designed to significantly enhance particle capture efficiency at a minimal increase in pressure drop compared to electrospun products.

Also new from H&V is NanoWave, an extended-surface air filtration medium that represents a critical breakthrough in synthetics technology.. Unlike conventional charged synthetic media that rely on charge and will often lose its efficiency in use, NanoWave mechanical filtration maintains its efficiency for the life of the filter. Compared to glass mat media, its highloft design delivers longer filter life and twice the dust-holding capability. And unlike glass, uitrasafe NanoWave won't shed fibers during processing, installation and use. NanoWave targets ASHRAE bag or panel filter applications including commercial and residential HVAC, paint spraying, vacuums, auto air, respirators and more.

MOGUL--Mogul Nonwovens, the concentration is on polypropylene and polyester spunbond, pure meltblown, SMS and various multilayer spunbond-meltblown composite products for filtration uses. These mainly target liquid filtration as well as medium-efficiency air filtration applications. The company also supplies vacuum cleaner dust bags and offers corona-treated meltblown and spunbond-meltblown composites for higher dust collecting capability.

"Our spunbond-melthblown composite product is currently being used in vacuum cleaner dust bags," remarked Mr. Gogus. %% supply our polypropylene and polyester spunbond into liquid filtration applications and we also sell our polypropylene spunbond and meltblown media for air filters. We recently developed a polypropylene/pulp/meltblown composite that we believe can bring different filtration characteristics due to the different pore structures of polypropylene and pulp."

GENERAL NONWOVENS--Another Turkish roll goods producer on the scene is General Nonwovens, which has recently expanded its involvement in the filtration sector in response to increased interest in replacing paper-like cellulose media with nonwovens. The company's products are 100% synthetic, consisting of either polyethylene terephthalate or polypropylene. General Nonwovens' FilterGen range includes lightweight and heavyweight polyester filter media. "Our thermally bonded polyester and polypropylene nonwoven layers do not have any type of chemicals on them," explained Alican Yilankirkan, business development director.

FilterGen lightweight polyester spunbond media is used as a reinforcement or coverstock layer for air and water filtration. The composite structures are used both with and without pleating. The pleatable, medium-weight ranges are used as coverstock media in a composite structure while the heavier weight fabrics are also pleatable and generally target air filtration.

Mr. Yilankirkan said that in most cases General Nonwovens' fabrics are used in combination with other filter media such as membranes, glass fibers, meltblown and nanofibers as a support layer. He said that an increase in the use of micro and nano fibers has helped drive growth.

MONADNOCK--Also specializing in composites for the filtration market is Monadnock Non-wovens. The company sells composites in slit widths from 6-60 inches for use in air and liquid filtration applications such as filter element and cartridge manufacturing, face mask, vacuum bag and other barrier or filtration applications.

In the last 12 months, the company has added new machinery to produce finer fibers and offer improved characteristics and more cost effective filtration. The company has also launched ECTFE/Halar meltblown as a new roll good for aggressive environments such as ozonated water filtration in the bio-pharmaceutical industry and strong acid or alkalis filtration in the chemical or power industries."

NORAFIN--On the other side of the globe, Norafin uses spunlace to target filtration end uses from its Allschwil, Switzerland-based headquarters. The company targets process air or hot gas filtration with its spunlace filter media and has recently introduced a self-pleatable filter medium that can be pleated without using a binder thanks to the metal scrim included in the material. "The filter medium consequently has much higher intrinsic temperature resistance and greater permeability, which offers a new opportunity especially for compact cartridge filters used in process air or natural gas filtration," explained Vincent Lorentz, sales manager filtration at Norafin.

In addition, Norafin developed materials to meet requirements in the field of process liquid filtration. "First tests have already been run where we could demonstrate that spunlace filter media offer a valuable alternative to the materials existing in the liquid filtration market today."

DELSTAR--Technologies also targets beth air and liquid end uses and supplies a variety of nonwovens and specialized plastic nets to the filtration industry. Products include Naltex netting, used primarily as a feed spacer and support in air and liquid filtration applications; Delnet apertured film, used as a pleat support in air and liquid filters, as well as a dust release layer in air filtration applications, such as vacuum bags; and DelPore meltblown media, a fine filtration media, calendered or uncalendered, customized for air and liquid filtration. DelStar also manufactures Coretec machined products, including plastic and metal filter components such as inner ceres for reverse osmosis elements, adapters and custom fittings for filtration systems.

DelStar's current product development focus is on advancing its line of engineered composites. In addition to thermal lamination technology, it has recently installed ultrasonic bonding equipment capable of combining multiple layers of material to produce unique filtration composites. "This technology allows us not only to customize products more specifically to customer needs, but it reduces the number of required components, inventory, suppliers and processing demands for our customers," said Ms. Wilcox. "Our ultrasonically bonded meltblown media composites, combined with our Delnet and Naltex nets, are pleatable and provide flow channels for air and liquid filter applications."

DONALDSON--Donaldson Membranes is also making strides in the filtration market with its new Tetratex brand of expanded PTFE membrane roll goods for industrial filtration applications. Tetratex 7018 is a new roll goods product used in high-end filtration baghouse process applications for air pollution control and product recovery such as: Ti[O.sub.2]--oxidizers, chlorinators, dryers, micronizers; medical and hazardous specialty incineration; lead--smelters, dryers, catalysts and others. According to the company, it is currently being used in Ti[O.sub.2] and micronizer applications where it has been well received in the market

Air Filter Media Adds tip

According to a recent report from INDA, the North American air filtration industry can be broken down into five key markets--industrial dust filtration, HVAC, disposable face masks, disposable vacuum cleaner bags and transportation, with the largest two subsectors being in-cabin filtration and air intake. "For these five markets, the filter media consumed totaled about 109,000 tons with a value of close to $600 million in 2007," stated Ian Butler, INDA's director of market research and statistics. "Of the 109,000 tons, about 40,000 tons is produced by the wetlaid/cellulosic technology, some of which are not technically a nonwoven material."