Polymer and fiber developments are adding high-tech properties to finished textile products.
By Jim Phillips, Contributing Editor
t a time when many manufacturers are looking for points of difference to set themselves
apart from the competition, there is one arena within the textile/apparel/fiber complex in which
proprietary processes and innovative new products are the norm. Performance fibers and polymers
account for some of the most advanced processes in the industry; and provide the means through
which significant advances are made in providing end-users with increased safety, enhanced comfort
and added convenience. On the commercial side, advanced fabrics provide structural reinforcement,
high-tech insulation, special coatings, fire barriers and more.
In this competitive arena, the operative word is "innovation." The race to develop something new, differentiated and sometimes, even, breakthrough creates an environment in which fabrics and fibers are infused with some truly remarkable properties.
Before Dow developed the new process, block copolymers of simple olefins, such as ethylene, propylene and a-olefins were attempted in the laboratory using a cost-prohibitive batch process similar to that used to produce other types of block copolymers styrene butadiene styrene (SBS) and styrene ethylene butylene styrene (SEBS), for example by using one initiator to make a single polymer molecule. Dows Insite manufacturing technology enables production of polyolefin block copolymer catalytically in the companys continuous solution polyolefin process.
"Developmental versions of the ethylene-based OBC were found to have better processing, elastic
and stress-relaxation performance characteristics that filled the performance gap between 'random'
polyolefin elastomers and styrenic block copolymers (SBC), which are currently widely used in the
form of elastic films, tapes and panels in health and hygiene articles," said Andy Chang, Ph.D.,
OBC is differentiated from other polymers by having hard and soft blocks within the same polymer chain. According to Dow, this imparts certain performance advantages, including improved elastic performance and improved stress-relaxation performance.
For applied strains greater than about 200 percent, Dow reports "random" ethylene-based and random propylene-based copolymers exhibit higher permanent set compared to styrenic block copolymers. In contrast, the OBC polymers exhibit permanent set values that are more similar to a formulated styrenic block copolymer for applied strains of 100 to 500 percent.
Stress-relaxation performance relates to the ability of an article to maintain fit. High amounts of relaxation lower loads translate to greater sag and poorer fit. Less stress-relaxation higher loads translates to better "holding force" and better fit.
OBC maintains higher stresses compared to a random copolymer, a styrenic block copolymer and a commercial diaper tab when stretched to 50 percent strain at body temperature and allowed to relax. This means better and differentiated fit over time when it is used as the primary elastic component or in combination with other materials.
As a consequence of OBCs various properties, Dow claims the elastomer not only bridges the performance gap between random polyolefin elastomers and styrenic block copolymers, but also exhibits differentiated characteristics that can translate to performance in medical and hygiene applications. Potential applications also include hoses and tubes; profile extruded products such as automotive weatherstripping; appliance, furniture and building/construction gaskets; crosslinked foams for industrial, consumer and footwear applications; closure liners for caps; and interior automotive parts.
Another polypropylene product new to the market is CoolVisions, a dyeable polypropylene fiber from FiberVisions Corp., with production facilities in Covington, Ga. CoolVisions is a disperse-dyeable fiber for use in ring-spinning applications. The product, according to FiberVisions, has essentially the same properties as solution-dyed polypropylene fibers, but, because it is disperse-dyeable, adds flexibility for the design and fashion-driven markets. Catering to the consumer trend toward softness, CoolVisions T-108 yields a soft, cottony hand even more than solution-dyed staple, according to the company. It can be blended with wool, cotton, cellulosics or man-made fibers; and can produce garments that are lightweight, comfortable and breathable with excellent moisture-management properties.
"While segmented pie and islands-in-the-sea processes are currently used to produce nonwoven materials for the household, industrial and personal hygiene markets, the advent of EastONE S85030 water-dispersible polymer will greatly expand the range of applications for nonwovens," Williams said.
Also new for the production of dispersible wet wipes is Nacrylic STP from Dallas-based Celanese Corp. The Nacrylic STP polymer system features a trigger mechanism that enables chemically bonded nonwovens to achieve a wipes desired wet strength during use, while dispersing in an excess freshwater environment. Nacrylic STP is, according to Celanese, ideal for chemically bonded nonwovens. The polymers can be applied by spray, print, foam and saturation.
Charlotte-based Polymer Group Inc. (PGI) recently introduced a new category of high-performance nonwoven fabrics called Spinlace®. These products deliver "high performance at best-value pricing," according to the company, through technology and product research.
The Spinlace manufacturing process incorporates continuous filament with hydroentanglement and eliminates the carding step. The process also uses PGIs proprietary Apex technology to integrate unique 3-D images directly into the fabric. Initial applications are expected to include consumer and industrial wipes. However, the company expects the product line to broaden into every market it serves. PGIs Benson, N.C., plant will house the first Spinlace line, which is expected to come online in the second half of this year.
In the area of comfort, Footjoy® has just introduced a new golf glove made from Holofiber®, according to Jim Ciccone, operations manager, Hologenix LLC, Fort Mill, S.C. Holofiber was introduced to the market several years ago, according to Ciccone, and provides properties that regenerate oxygen back into the skin. Footjoy claims the properties of Holofiber give its new ShockStopper® golf glove the ability to provide maximum cushioning and grip performance, while minimizing club vibration. Holofiber also has been used in a number of medical and comfort applications, including an antimicrobial sock manufactured for diabetics, since its introduction several years ago.
DAK Americas LLC, Charlotte, recently introduced SteriPur FC® and Airloft® to its family of specialty polyester staple fibers. SteriPur FC is engineered to be Food and Drug Administration-compliant for food contact. Airloft is a high-void hollow fiber for nonwoven and fiberfill applications.
Structural Fibers And Composites
Fibers for structural or industrial applications require high strength, high stiffness and other properties, depending upon the ultimate end use. Zoltek Corp., St. Louis, a manufacturer of carbon fibers, has developed Pyron®, a fiber finding a home in flame-retardant fabrics, according to Zolteks Mark Davidson, Pyron products account manager. Pyron is an oxidized polyacrylonitrile fiber that blends the high temperature and flame resistance offered by carbon with manageable processability for textile operations. Pyron has been processed into yarns for woven fabrics and used extensively in needlepunch, spunlace and other nonwoven techniques. Pyrons standard density product and Pyron Plus, a higher-density version, both score well in a Limiting Oxygen Index test a common benchmark for flame-retardant fibers. Davidson said there are no chemical additives to improve these readings; Pyron is inherently fire-resistant.
From Germany-based BASF AG comes Acrodur®, a formaldehyde-free binder for use in molded fiber components. The molded components can be made from wood and/or other natural fibers, and are used for such applications as automotive instrument panels and interior trim. Acrodur is an aqueous single-component system consisting of a modified polycarboxylic acid and a crosslinking agent containing hydroxyl groups. It is a storage-stable single-component system, according to BASF. Before curing, it is thermoplastically deformable; and afterwards, it has duroplastic, mechanically stable properties.
Air Products Inc., Allentown, Pa., has created Flexbond® AN214, a fine particle-size aqueous dispersion of a self-cross-linking vinyl acetate/acrylic copolymer. The product forms a hard, tough plastic film and exhibits resistance to water and aging, as well as slow swelling in chlorinated hydrocarbons. Because it forms a particularly hard film, Flexbond AN214 dispersion is targeted for such applications as a sprayable binder for waddings and as a finishing agent for woven and knitted goods.
Omnova Solutions Inc., Chester, S.C., has developed Omnapel 3158, an aqueous emulsion of a hydrophobic acrylic copolymer, for applications in specialty nonwovens and paper. The company recommends using the product for applications requiring ultra-hydrophobicity/barrier characteristics, superior resistance to heat and ultraviolet (UV) exposure, high wet/dry strength and a medium hand.
thermoplastic polyester elastomer offer enhanced UV stability.
New technology has provided enhanced UV stability for the monofilaments made with Riteflex® thermoplastic polyester elastomer from Ticona GmbH, Germany. Polyester monofilaments made with Riteflex thermoplastic polyester elastomer have more than 90-percent property retention in color and elongation, for example at UV exposures of as much as 1,500 kilojoules per square meter when tested according to SAE J1960. As a result, the fibers are targeted as solutions for auto seating, outdoor furniture and other applications exposed to sunlight. The product also provides a high barrier for liquid water while allowing the transmission of water vapor preventing mold formation when used as fabric for furniture, auto seating or incontinence pads.
chlorine-resistant spandex suitable for swimwear.
According to the company, S-17Bs protective features prolong the wear life and enhance the appearance of swimwear and lingerie, providing end-use customers more value for their money.
RadiciSpandex S-45 yields disperse-dyed polyester stretch fabrics in various colors with dyeing versatility, elimination of cationic polyester fabric streakiness and American Association of Textile Chemists and Colorists wash-fastness ratings of 4 to 5. S-45 provides an economical opportunity for apparel producers to market garments in polyester stretch fabrics with a clean, colorful appearance, according to the company.
Hyosung Corp., South Korea, is building a new creora® spandex facility in Turkey (See "Fiber World News," TW, this issue). "We are investing in Turkey as part of Hyosungs global growth strategy and to demonstrate our commitment to the textile industry," said Greg Vas Nunes, president, Europe and the Americas. "The new factory will be located in Cerkezkoy, near Istanbul, to ensure fast and reliable delivery locally as well as to African and European regional customers," Vas Nunes said.
Hyosung's Creora H-350 is a high-heat-resistant spandex that provides aesthetic and economic benefits for the end-user, according to Hyosung. Some features include lasting power fit and freedom of movement, long-lasting color wash-fastness when blended with polyester, and excellent knitting efficiency.