Nonwovens Flow Into Filtration

June 14, 2005

stringent standards and heightened awareness lead to innovation

Unlike many markets for nonwovens, which have reached maturity in recent years, filtration is still viewed by many nonwovens manufacturers as a market with untapped reservoirs of opportunity. Often difficult to categorize as a whole, because of its high number of applications and end use segments, filtration continues to offer plenty of opportunities in terms of both new products and geographical penetration.

Catalysts triggering growth in filtration include an awareness among media suppliers and consumers as to why filtration is important. Government regulations are also creating extended business segments for nonwovens manufacturers.

“New opportunities exist for media that create cleaner air and water,” explained Chris Coates, vice president of filtration specialties at Ahlstrom FiberComposites. “Pollution is a big issue, and media help keep our food, water, pharmaceuticals and air cleaner and healthier. On the other hand, engine filtration has new emission requirements and legislation worldwide, which continues to drive an enormous amount of change in the technical requirements of filters. Otherwise, new global threats, such as disease and terrorism, are raising awareness of filtration needs to the general public.”

Filtration applications are all divided into two main areas—air and liquid. However, within these areas lies myriad applications. For instance, in the air or dry segment key areas include heating, ventilation and air conditioning and cabin air filters while on the liquid or wet side of the filtration business, filters for water filtration, swimming pools and petroleum and food processing are key areas of interest. This scope has required manufacturers to specifically tailor each material to the exact needs of the end use application.

“Filtration applications are customer and end use specific,” explained Frank Baker, market manager for BBA FiberWeb Filtration, Old Hickory, TN, which currently offers 15 trademarked filtration media products. “Perhaps the most important factor is being able to design products that truly add value while delivering the needed performance. This involves an innovative process that takes full advantage of the available fibers, technology and know-how to deliver value, efficiency and cost-effectiveness.”

Nonwovens Grab Share
To provide a quality, cost-effective product, manufacturers focus on several main areas when creating media material. These include flow rate, pressure drop, loading capacity and efficiency. The importance of each of these ratings depends on the segment and the end use in which the media will be applied.

“In air filtration applications, pressure drop and loading capacity are critical factors,” said Mr. Coates. “Meanwhile, liquid applications tend to focus on particulate removal, loading capacity and wet strength, while pressure drop is generally a secondary factor.”

Although filtration applications can use a variety of nonwoven web forming and bonding technologies, wetlaid and meltblown materials, as well as various composites, continue to drive significant growth for nonwovens in filtration. “Nonwoven media are mainly designed to replace glass fiber media in filtration that are known to bear health-endangering risks,” explained Ulrich Hornfeck, sales director of Schwarzenbach/Saale, Germany-based Sandler AG. “Another important aspect is the easy handling of used filters in incinerators.”

In addition to environmental drivers, demand for higher efficiencies continues to create a need for smaller diameter fibers in filtration. Meltblown, microglass and microsynthetics for wetlaid are common examples for this as well as solvent electrospinning and splittable fibers in wetlaid.

Also witnessing the growth of wetlaid materials in filtration is Crane Nonwovens, Dalton, MA. The company supplies Craneglas, a nonwoven formed by a special wetlaid process from chopped strand glass fibers of uniform length, to the industrial, commercial and consumer markets and Cranemat, a wetlaid, thermal bonded nonwoven with polyethylene, polypropylene or bicomponent fibers for membrane-casting substrates, cartridge support and gas and liquid filter media. Crane has also developed custom versions of its newer Craneglas 500 nonwovens, which are composed of silica fibers.

“Filters have to perform—often for extended periods of time—in challenging environments where thermal stability and/or chemical resistance are paramount to performance,” explained Matthew Miller, manager of technical marketing and business development for Crane Nonwovens’ Technical Materials business. “Furthermore, using nylons, PVC, PPS and fluoropolymers allow us to offer materials suited to specific environmental situations. For example, PVC is suitable for use in heavily chlorinated fluids.”

Also gaining ground is the use of antimicrobials in nonwovens for filtration, which are used to custom tailor nonwovens for a specific application and diversify manufacturers’ product lines. Hollingsworth & Vose, East Walpole, MA, recently launched a carded, polyester, thermally bonded nonwoven engineered to filter swimming pools and spas. The product, with inherent antimicrobial properties, will enhance pools and spas filters by offering added protection.

“The antimicrobials are not a second coating that can eventually wear off, leaving the filter unprotected,” explained Dino Abelli, market manager for liquid filtration and respiratory/face mask filtration for H&V. “Carded, thermal bonded nonwovens offer the ability to use a wide variety of fiber types and sizes, making them ideal for this and other liquid filtration applications.”

H&V also offers an NSF-Class 61-(The Public Health and Safety Company) certified line of meltblown polypropylene nonwovens for liquid filtration applications. Granted in early 2002, this NSF standard regulates the potential health effects of drinking water components. “Points of use, whole house and process filter manufacturers can be confident in the use of our NSF-certified liquid meltblown for a variety of end uses requiring NSF- or Food and Drug Administration (FDA)-approved materials,” explained Mr. Abelli. “Also benefiting from the certified meltblown are our existing customers and potential customers. Any necessary end-product testing becomes less expensive for them while the testing and qualification process is shortened.”

Although government standards like NSF-Class 61 are just as varied as the scope of filtration applications, they are a crucial part of the filtration industry and cannot be overlooked. These standards serve as chief guidelines in creating media, and filtration media manufacturers are ramping up efforts to educate customers on what specifications are included in filtration certifications.

Decrypting Standards
Stringent filtration standards exist in all areas of filtration and have spurred manufacturers to improve performance of both their media and filters. Through increased education, end users have also become more aware of the importance of indoor air quality in recent years. “There is more demand for higher efficiency air filtration media to meet the minimum efficiency rating volume (MERV) ratings 52-1 and 52-2,” explained J.C. Sneyd, director of sales and marketing for Roswell, GA-based Kimberly-Clark Nonwovens. “End users today are far more educated about the benefits of better indoor air quality. The pace of this education is accelerating and will continue to grow.”

While this increased customer awareness is keeping manufacturers occupied in the research and development arena, these standards have made participation in the liquid filtration market riskier than in air filtration. “With an air filter, it can be easily changed if it doesn’t work properly, but a filter that does not work in a liquid filtration product can have ramifications beyond just the filter cost,” Mr. Sneyd explained. “Manufacturers are a little more reluctant to enter the liquid filtration market due to fragmentation and lack of industry standards.”

H&V’s antimicrobial meltblown material K-C's pleated filters
Ahlstrom’s pleated filters K-C's media for HVAC applications

Despite these obstacles, Mr. Sneyd stressed the importance of making media certifications in this area highly publicized to customers.

All of K-C’s liquid filtration products, for example, are 21-CFR approved—a standard in the food and beverage segment. This includes the company’s Fathom liquid bag media, a bicomponent polyolefin nonwoven. Thermal bonded for strength, Fathom media are chemically compatible with most liquid applications, such as water treatment, recirculating coolants, microfiltration prefilters and scientific separations, and does not contain binders. The media also stand out for its engineered gradient density structure that provides improved filtration efficiency in trapping solids.

Crane’s Mr. Miller also stressed the importance of cracking filtration standards’ codes to customers and end users. “I would be loathed to suggest we go back to the days of ‘pick any number you want’ for a nominal filter rating. We have to continue to communicate with end users, so that they understand what product they are getting without burying them in standards’ jargon.”

Filtration standards have also been born out of a need for more flexibility among customers. Manufacturers now offer a variety of certified, environmentally friendly filtration media products to customers, depending on the end use application. H&V, for example, launched a new solvent impregnation line in Hawkinsville, GA in August. The line allows its customers to select the level of cure for engine filtration media. Among these levels are Intermediate B-staged (IBS-15-30% cured), Intermediate Cure Resin (ICR-40-60% cured) and Advanced Cure Resin (ACR-70-90% cured).

“This technology offers greater flexibility for our customers in meeting stricter environmental compliance measures as well as reducing energy consumption from curing media at their plants,” explained Robert Murphey, vice president of marketing and technology of H&V’s Engine and Industrial Filtration segment. “We have also introduced Nanoweb, produced at our Hatzfeld, Germany location. This technology offers the ability to apply very fine layers of 0.2 micron diameter fibers on support media. These two products address environmental concerns with cleaner, lower polluting resins and finer filtration efficiencies.”

Also impacting H&V’s engine filtration business are pending regulations regarding diesel particulate emissions and Nitric Oxide (NoX) reductions. These regulations are expected to become effective in the U.S. and in Europe in 2004 and will significantly shape the engine filtration market. “Increased combustion efficiencies are required to reduce the NoX production and the level of particulates in diesel exhaust,” Mr. Murphey said. “The result is the need for dramatic increases in fuel filtration efficiencies and increased levels of water separation, required to support the higher injector wear.”

H&V has developed an extensive offering of composite media to meet the needs of engine filtration for the next 10 years. The company’s composites are being developed to offer increased protection in components such as fuel injectors and gas turbine blades. This will help H&V customers meet new engine emission standards such as common rail diesel fuel filtration.

Filtration—Always Needed
The current events, regulations and trends that are shaping the filtration industry today will also impact this market’s future. Of particular interest to nonwovens manufacturers is the heightened awareness of impending future outbreaks of Sudden Acute Respiratory Syndrome (SARS), as well as threats of nuclear, chemical and biological warfare. Many companies reported sales spikes in the filtration business last winter and spring. “The SARS outbreak had a significant impact on demand and sales of our meltblown material in disposable respirators,” explained H&V’s Mr. Abelli. “We have also been expanding our global presence during the last two years, with the Far East being our largest growth area.”

Growth in the Far East, Europe and South America has been so promising to filtration manufacturers, that many recently opened sales offices or constructed facilities in these regions. Lydall Filtration and Separation, Manchester, NH, opened a sales office in Asia during the third quarter of this year. The company was attracted to Asia because of its high tech industries and the rapid pace of Asia’s economy.

Crane Nonwovens has produced custom-tailored versions of its Craneglas 500. The company’s efforts include broadening the weight range and working with higher temperature binders.
Ahlstrom FiberComposites has also reaped the benefits of the booming Asian economy. The importance of this region to the company is evident in its recent $32 million investment in Hyun Poong, Korea. The company has also gained ground in Brazil, with an upgraded filtration line in Louveira, and in Europe, with the purchase of Spanish filter media and specialty paper supplier Papelera del Besňs.

As nonwovens manufacturers look to penetrate new geographic markets, they will also seek out ways to add value to their products so that nonwovens continue to replace other conventional filtration media, such as woven, paper and glass.

“This includes characteristics such as longer filtration life, superior performance, disposability, pleatability or inventory advantages,” BBA FiberWeb’s Mr. Baker said. “The fibers in a nonwoven structure, compared to a woven, are arranged in a more open structure, providing very effective use of individual fibers. As a result, the fiber’s shape has a pronounced effect on filtration in a nonwoven structure.”

Gas Phase Media—A Growing Niche For Filtration
AQF Technologies, Charlotte, NC, a division of BBA Fiberweb, specializes in gas phase filtration media for the indoor air and cabin air markets. AQF’s media, which use activated carbons, attract airborne molecular contaminants either by physical or chemical adsorption. The nonwoven matrix is comprised of only two raw materials—the bicomponent polyethylene fiber and the functional adsorbent. When heated, the outer sheath of the bicomponent fiber attaches itself to the functional particles. Since no adhesive is required to form the web matrix, a maximum amount of sorbent surface area is exposed, thereby enhancing filtration performance.

“Gas phase filtration is an immature market primed for the introduction of new products,” explained Chris Sipes, account executive for the North American indoor air business. “Filtration has been identified as a target market for many nonwovens producers in recent years, as it provides opportunities for innovative products and engineered solutions. Providing performance filtration products enables manufacturers with R&D capability to find premium products that will compliment a portfolio of commodity-oriented goods. This is certainly true for gas phase segment of the filtration market.”

Related Application:

Related Technology:

Related Other: