| As nonwoven materials continue to penetrate world markets, so too, does the need for fiber finishing technologies that are essential in their manufacture as well their proliferation. A boom in nonwovens production has given fiber finish suppliers reason to constantly seek new and improved technologies that deliver value and cost efficiency to their customers. Whether a nonwovens producer seeks finishes that facilitate the manufacturing process or add value to the needs of converters and end use suppliers.
Nonwoven goods are rapidly serving applications with specific performance requirements, often substituting for traditional woven or knit fabric constructions. Surface chemistry, either applied to the fiber as a finish, or later on the formed fabric, is perhaps the most efficient route to add value to the nonwoven fabric and solve specific end-use problems.
Generally, fiber producers no longer possess the internal staff to develop these solutions, choosing to focus solely on production. This has make them more dependent on finish than ever. Eventually, experts predict, nonwovens are likely to follow the same path as traditional fabrics where most effective solutions are provided by cooperative developments between fiber and fabric producers, finish and auxiliary suppliers and the end-user.
Separation of Services
The existing diversity of nonwovens production makes it difficult to narrow the scope of finishing technology. Nonwoven roll good manufacturers may produce the fabrics, finish them and convert them for sale. Other companies may simply produce the roll good for another company which treats and sells that material. In turn, other companies may purchase roll goods, send them elsewhere for finishing, converting and packaging and offer that specifically finished product to the customer.
There are a variety of applications that may be performed on a nonwoven substrate to make it perform better. In environments such as electronic clean rooms, auto-paint preparation or in operating rooms, for example, lint can be a problem. Materials being applied in these segments receive chemical treatments to lock their fibers in place to avoid lint. Or, in other cases, nonwovens may need to be strengthened to withstand pulling and stretching or made repellent to water or other substances. Even the feel of a fiber can be affected.
Recent trends have drawn a line between the companies that produce the fibers and those that produce the chemicals to finish them. As this separation evolves, experts stress that communication between producers and finishes is essential. Clariant, once part of a larger fiber producer, has an inroad to some fiber producers as a result of this past affiliation. The relationship helps facilitate understanding about how the fibers are produced and what can be done to custom tailor finishes to solve the customer's problems. “In reality, what really counts in this business is connections. The fiber producers have to trust you--let you in and let you run trials. That, plus efficiency, is what drives the market,” said Mr. Balekjian.
Whitford Worldwide, Westchester, PA, is a custom compounder of high performance coatings. Traditionally a maker of non-stick coatings for pots and pans, the company has overlapped into industrial applications such as corrosion an chemical resistance. In doing so, Whitford has taken a unique approach to customizing nonwovens producers’ needs for chemical finishes.
“As a custom formulator, the company is trying to offer performance enhancements to a textile producer or fiber manufacturer that is not possible to accomplish by purchasing an of the shelf material on the market,” said Kurt Mecray, technical director for Whitford Worldwide.
Flourochemicals, for example, can become ineffective after a limited number of washes. Whitford may use a flourochemical to achieve water repellency, but in combination with other materials, such as a resin, to improve durability. “Customers in nonwovens markets are demanding attention,” said Mr. Mekray. “The entire textile industry has been very self reliant on solutions to problems or to performance enhancements. They are familiar with things like flourochemicals, but they don’t historically look outward to other types of possible answers to what they’re trying to accomplish.”
Mr. Mekray said that not many companies are willing to make custom materials specific to a customer’s application because it’s time consuming, difficult and a tax on any custom manufacturers’ inventory and manufacturing process. Finish companies are instead looking to fine-tune and optimize the production process so they’re making less frequent larger batches, which does not lend itself to customization.
Diversity in Needs
The French word for fiber finish is avi vage, which means “to bring to life.” When first extruded, synthetic fibers such as polyester and polypropylene are simply a piece of plastic, not a natural fiber such as cotton or wool. Fiber finishes accompany the fiber throughout the entire manufacturing process, most commonly in a topical solution. A finish allows the fiber to pass through machinery. Without it, friction would immediately stop the machine.
“Friction causes static, static causes voltage problems and that endangers your people,” said Uniqema’s sales development manager, Vinod Palathinkara. Uniqema provides both formulated spin finishes and ingredients for man-made fiber production. Its finishes provide critical effects such as lubrication, antistatic protection, emulsification, wetting and wicking to the surface of synthetic fibers.
Some performance properties imparted by fiber finishes include functional characteristics such as moisture refrain and transport, absorbency of repellency, flame retardency and anti-static and anti-frictional behavior. They may impart aesthetic properties, also, such as appearance, surface texture, color and odor.
Eastman Chemical Company, Kingsport, TN, recognized a need in the areas of anti-linting, improved strength and repellency and absorbency in markets such as automotive, wipes, filtration and medical. To address these needs, the company has introduced its Synthebond line of topical finishing chemicals used to improve performance of nonwoven substrates.
“The advantage of a topical finish is they can be added to any nonwoven, regardless of how they are formed,” said Wayne Steinberg, business manager of textile chemicals for Eastman. “As opposed to concentrates, which may be added during the production process and used only during the spunbond or meltblown process.”
The Synthebond nonwovens product line features a range of binders, performing finishes, softeners and soil release agents which fall into five key technology groups. Included in the line are AC Emulsion Polymers, a series of conventional acrylic, vinyl and acrylic and styrene and acrylic emulsion polymers.
The product is composed of both self-crosslinking and non-crosslinking polymers for use in durable and disposable nonwovens for improved hand building properties.
Also in the line are the FX Flourochemical Extenders, acrylic emulsion polymers that impart durability and repellency extension when combined with flourochemical emulsions. Mr. Steinberg said that when used in conjunction with expensive flourochemicals, this product would help lower a customer’s cost, which is the “Holy Grail” of chemical applications.
As a departure from topical solutions, some companies are producing combinations of polymer additives that will exude to the surface of a fiber when applied into the polymer melt. This technology is not particularly new; pigmented additives were a good example of this. Topical applications tend to be less expensive and therefore are the industry norm. This has led companies such as Goulston Technologies to look at more specialty polymer additives in an attempt to affect certain surface properties more permanently. Goulston’s focus is concentrated on spin finishes, or fiber lubricants, and getting them into nonwoven fabrics, particularly for the card and bonding techniques for hygienic, diaper top sheets, wipes and padding applications. The company’s experience with polymer additives--historically a costly process--has taught it that commercial viability is case specific. “In today’s market, the raw materials are increasing quite substantially,” said Roger Crossfield, president of Goulston.
One company banking on the future of polymer additives is Polyvel, Hammonton, NJ. The company is a specialty concentrate producer dedicated to the development and marketing of high performance, cost-effective additive concentrate systems for use in polymers. The concentrates contain extremely high levels of heat and shear sensitive additives.
The systems are compatible in a broad range of polymers and, said Robert Axelrod, Polyvel’s vice president of sales and marketing, offer improved economics, ease of handling and efficiency in dispersion compared to polymer additives in the past. All of the concentrates are finished in a dust-free pellet form or custom ground into a uniform powder.
The company's additives are introduced to the meltblown process to increase the flow or decrease the viscosity of meltblown polypropylene fibers. The additives reportedly allow the extrusion of smaller denier fibers to increase efficiency in filtration. Mr. Axelrod added that his company’s peroxides could help diffuse the increasing cost of high-flow polypropylene for fine denier materials. This is achieved, he said, by using the less expensive combination of Polyvel peroxides and low-flow polypropylene.
In spite of the incessant call for less expensive products, fiber finish manufacturers, as with all users of oil-based products, must continue to juggle rising raw material costs and customer demand. As more uses are found for engineered fibers and fabrics, technology must keep pace by imparting the characteristics that will make them viable for multiple applications.
To be successful, finishes and manufacturers must come together to realize each others’ needs as rising costs, environmental concerns and government regulations narrow the field in the new textile frontier. And, cooperation can no longer wait as rising oil costs drive up the price of doing business.
“With the current rise in oil prices, some people will be happy to even get their raw materials,” said Clariant’s Mr. Balekjian.