A view into the vast field of manufacturing and application of industrial textilesThe
technical and technological application of textiles has become a rapidly growing field, especially
over the past two decades. For example, even though some textile seat belts for automotive
applications were installed before the 1960s, nobody imagined then how large a role textiles would
play in passenger safety. The demand for seat belts, as well as supplemental restraint systems such
as air bags, is huge. And while this is only the result of about two decades, we now have a better
feeling for how the market for such technical safety textiles will grow.

There are thousands of applications of textiles today for industrial and consumer usage.
Additionally, many potential uses have not been explored because end users arent aware that textile
fabrics and composites can effectively replace many traditional materials. Industrial textiles are
not in the spotlight like flashy brand-name apparel textiles and live almost a secret life, often
hidden from the eye of the end user. And the manufacturers of high-technology industrial textiles
are (understandably) very secretive about their manufacturing processes and the design of their
fabrics. The market for industrial fabrics and engineered textiles is growing constantly and
becoming increasingly significant. This leads to technical developments and innovations of advanced
textiles for new tasks. A growing awareness can be observed of environmental demands, e.g., methods
of filtration, or of the substitution of textiles for conventional materials. A great effort is
geared toward the development of cheaper, easy-to-install and lightweight textile components (in
the automotive industry, for example) based on textiles.Dream It, And It Will Be TextilesThe
following list of applications is based on a summary of fields that was compiled over the years by
Sulzer Textil Ltd., Switzerland. The company has been in the field of woven industrial applications
for many decades and set many of the original benchmarks for this sector with the introduction of
the Sulzer Projectile weaving machine. In geotextiles, woven industrial fabrics are selected for
their stability and strength, while nonwovens are often selected because of their cushioning,
damping and liquid filtration properties. Each individual manufacturing technology, in combination
with specific fibers, has certain advantages in a particular field. It seems that the nonwovens
technology has an even more impressive growth rate over the past years when compared to all other
industrial textile manufacturing technologies. Unlike consumer-oriented textile producers, the
industrial textile manufacturers face challenges presented by fibers that are extreme in nature and
chemical origins. Also, physical and mechanical properties of fibers and yarns are often very
different from those used in typical consumer textiles. The distinct design of fabrics for
industrial applications often requires special devices and setups on the production machinery.
Textile manufacturers are understandably very secretive about machine settings and installations.
Many of the nonwovens installations show a specific custom layout, and weavers have to purchase
expensive, wide, reinforced or specially equipped weaving machinery to be able to produce the
desired industrial fabrics. However, it seems to pay back when one compares the profit margins of
the industrial fabric segment with those of the rest of the textile industry.Industrial TextilesAs
already mentioned, woven textile products, nonwovens and knitted textiles share each segment of
industrial textiles, while the actual percentage assigned to each individual manufacturing
technology may vary from application to application. The technical specification profile,
cost-effectiveness and practical performance determine which manufacturing technology receives the
lions share. The following list provides a general overview of all major fields in which textiles
play a significant role.

• Protection and safety-related textiles
• Public services
• Medical and healthcare applications
• Agriculture, horticulture and fisheries
• Buildings and light structures
• Transportation
• Packing, transporting and shipping
• Filters and other industrial applications
• Miscellaneous applications of textiles
• Geotextiles

Following are some selected sub-categories of industrial textiles.Protection, Safety

These are mainly textiles that have a role in protecting the environment and humans from
leaks, spills, falling debris, fire, heat radiation and resulting accidents.

• Protective tarpaulins and netting (e.g., for scaffolding)
• Extinguishing blankets
• Safety nets
• Fire-resistant fabrics
• Fluorescent fabrics
• Insulating fabrics
• Reflecting fabrics
• Gas-proof fabrics
• Water-repellent fabrics
• Waterproof fabrics
• Microporous fabrics
• Oil-repellent fabrics
• Acid-resistant fabrics
• Fly screens
• Mosquito netting

Public ServicesThese textiles are used by the military, fire fighters, police and similar
institutions to camouflage, shelter and protect their forces.

• Camouflage netting
• Camouflage fabrics
• Army tents
• Fabrics for protection against projectiles and shrapnel
• Fabrics for peace-keeping and battlefield applications
• Fabrics for uniforms
• Nuclear, biological and chemical (NBC) protective fabrics
• Fire-fighting suits and fabrics
• Parachute fabrics
• Packing materials for defense applications (e.g., sandbags)

Medical, HealthcareThis is an ever-growing sector, especially for nonwoven applications,
because many textiles in this field are either one way or do not need to withstand high stress
levels and long-term cleaning cycles.

• Barrier fabrics for the operating theatre
• Fabrics for medical courtesy
• Fabrics for casts
• Orthopedic fabrics
• Stabile bandages
• Elastic bandages
• Cotton gauze bandages
• Fabrics as mattress and pillow protectors
• Diapers (babies, incontinence)
• Sanitary napkins
• Medical sutures

Agriculture, Horticulture, FisheriesThis sector is mainly dominated by knitted and woven
fabrics. In agricultural applications, very wide fabrics and vast square yardage especially find
their applications.

• Shade and energy-saving fabrics for greenhouses
• Ground cover fabrics
• Tie-ribbon and tape for fruit crops and similar applications
• Bags and nets for storage
• Fabric for root ball packing
• Netting for enclosures (e.g., grazing)
• Protective fabrics and nets
• Twine and cordage for enclosures
• Textile products for bagging and wrapping purposes
• Draw cloth for mushroom cltivation and rabbit breeding

Buildings, Light StructuresThis is a vast field of applications that often challenges the
highest standards of color fastness, UV resistance, strength and durability.

• Insulating and draining fabrics for buildings
• Roofing textiles
• Indoor sun screens
• Outdoor sun screens
• Awnings
• Shading fabrics
• Draught strip for doors and windows
• Reinforcing fabrics for plaster
• Tent fabrics and camper/trailer extensions
• Fabrics for marquees
• Fabrics for light-permeable structures

TransportationThere are thousands of individual applications when considering all forms of
transportation, such as motorcycle, car, bus, train, trolley, aircraft and ship. Besides the
comfort textiles (covers, decoration) for personal and industrial applications, there are many
technical textile applications hidden from the eye because of surrounding rubber or plastics.

• Passenger compartment linings
• Car trunk lining materials
• Mats
• Coated textiles (dashboard, door panels, etc.)
• Upholstery fabrics for car, bus, train, trolley, aircraft and ship seats
• Fabrics for decorative and sound-proofing applications in trains, trolleys, aircraft and
  ships
• Aftermarket seat covers
• Seat belts
• Air bag fabrics
• Tire cord fabrics
• Structural support fabrics for fan belts, timing belts and hoses
• Noise and heat damping/insulating materials

Packing, Transporting, ShippingThere are a host of applications in this arena. Applications
range from wrapping a piece of jewelry to wrapping an army tank. Following is a sampling of the
various applications.

• Cargo and container nets
• Mail bags
• Money bags
• Large textile bags
• Fabric for conveyor belting (coated and uncoated)
• Polyolefin fabrics for packing
• Fabrics for shopping bags, shoulder bags, backpacks, etc.
• Suitcase fabrics (outer shell and lining fabrics)
• Textile wrappings for car tires
• Industrial packing (bags in polypropylene, jute, etc.)
• Canvas and tarpaulin fabrics for shipping protection
• Container fabrics for silos (e.g., for water)
• Helicopter nets

Filters, Other Industrial Applications

An amazing technological area is the world of textile filters. Some high-tech filters are
used for blood filtration in the medical field. Workshop materials as well as polishing and sanding
tools often contain a textile core. Again, the array of potential applications is seemingly
endless. A partial listing follows.

• Filter fabrics from extremely fine mesh to coarse mesh
• Wet-filtration applications
• Dry-filtration applications
• Open-weave fabrics
• Tubular fabrics
• Felt fabrics
• Fabrics for polishing discs, cutting discs, abrasives
• Belts, etc.
• Technical textiles for electronic applications
• Technical textiles for heavy engineering
• Technical textiles for papermaking, printers, laundries and the cement industry
• Industrial pulley drive belts

Miscellaneous ApplicationsAgain, touching just the tip of the iceberg, the following listing
contains only a few textile applications that play important roles in their specific fields of
utilization.

• Woven primary carpet backing
• Secondary carpet backing
• Artists canvas
• Cinema screens
• Canvas for film sets and theatre scenery
• Umbrella fabrics
• Fabric for parasols, deck chairs and windbreakers
• Textiles for specific sports applications (e.g., judo mats, outdoor mattress covers, etc.)
• Fabric for sports shoes and slippers
• Base fabrics for coating
• Base fabrics for flexible lamination
• Fabrics for shower curtains

GeotextilesThis is a vast and rapidly growing field of applications. It is estimated that only
about 20 percent of all possible applications for textile products have been developed. It is
usually the end user who cannot imagine a textile product that could lead to significant
improvements and savings. However, for geotextile applications, it is often the textile
manufacturers drive to research and educate their customers that leads to new textile products.
Companies like Synthetic Industries, Chattanooga, Tenn., for example, offer a broad range of
geotextiles for civil and environmental engineering, as well as fabrics for erosion control and
storm water management. The company offers high-strength woven geotextiles for soil stabilization,
reinforcement and containment; and nonwoven geotextiles for drainage, separation, cushioning and
pavement overlay. Its geotextiles and erosion-control products are distributed in more than 50
countries. Following are more applications in geotextiles.

• Textiles for engineering water flow and road drainage
• Roadway separation and railroad stabilization
• Textile product reinforcement of earth, slopes and hills
• Erosion-control blankets
• Turf-reinforcement mats
• Fabrics for landfill rehabilitation
• Surface fabrics for sport grounds
• Protective fabrics for pond foils
• Engineered water-filtrationfabrics

August 2000

 first Internet chemical marketplace to provide a neutral market where buyers and sellers of
all sizes can conduct both large and small transactions.Covalex. com empowers buyers with pricing
and product information that helps them make smarter purchasing decisions, said Bob Steel, chairman
and CEO. The site exposes suppliers to new customers and reduces the costs and time associated with
completing a transaction all directly impacting the bottom line.The sites supply-chain management
offering will help companies to better manage costs and inventories by streamlining the evaluation,
purchase, tracking, distribution and procurement processes. Accurate, real-time global, national
and regional market information will also be available through Covalex.coms information
bureau.Conducting business on the Web will be a necessity for those who want to remain competitive
in their industries, said Steel. Covalex.com helps companies realize cost savings and operating
efficiencies today. Long term, it will help ease industry issues like price volatility and
imbalances in supply and demand.

August 2000

The multi-storied behemoths that dot the landscape of the American Northeast and South serve as a
reminder of days when companies built physical facilities to be viable producers for more than a
half-century.Today, however, many companies build plants with much shorter life cycles. Its not
uncommon to see plants built as late as the 1960s or early 1970s no longer in use, according to
industry engineering/construction consultants.Machinery changes so quickly now, said Wilson
Tillotson, division manager, manufacturing, Lockwood Greene, a Spartanburg, S.C.-based engineering
company. Buildings that were well-equipped for the latest manufacturing technology just a decade
ago are woefully obsolete today.Automated processes, such as new doffing mechanisms for roving and
spinning frames, require a different physical layout than older, more labor-intensive machinery.
High-speed rapier looms need stronger, more stable flooring with less vibration; air-jet machinery
taxes the capabilities of air compression systems; and temperature/humidity requirements stress the
air conditioning.It is not uncommon to see companies move more toward pre-engineered construction,
especially for some of the lighter processes, Tillotson said. You will likely see more and more
companies gravitate in this direction.Pre-engineered facilities are suitable for such functions as
cut-and-sew operations, Tillotson said. Heavier manufacturing, such as spinning and weaving,
however, still require substantially more structural strength.The two biggest obstacles that
confront most new facilities are environment and electronics, according to Neal E. Tonks, Ph.D.,
director of manufacturing, Bayer Corp.s Bushy Park plant near Charleston, S.C.Environment is, of
course, an old issue, one that textile companies have faced regardless of when and where theyve
built new plants. Electronic considerations, however, are relatively new to the industry so new, in
fact, that it is easy to overlook their importance until painful and costly experience teaches
otherwise.

The level of computerization in our operation is significant, Tonks said of the Bayer plant.
The Bushy Park plant, which manufactures Bayers Dorlastan® spandex fiber, recently underwent a
$60-million expansion. Computerization represents fully 25 percent of our total investment cost. We
have a sophisticated control system that monitors our processes to ensure exact tolerances. Just
the exercise of running cable trays was a major factor in the design of our facility of making sure
we had the right infrastructure in place to get power and computer control to where it was
needed.Tonks said it wouldve been a costly and time-consuming venture had electronic considerations
not been such a high priority with the Bayer design team. It wouldve been a nightmare if we hadnt
given thought to how we were going to design the electronic layout.In general, though, I believe
these considerations are still an afterthought a lot of times. We are so focused on reaching
economies of scale of fitting maximum production capability into minimum space that we overlook
having the infrastructure in place to make the most efficient use of what we have.Environmental
issues remain a primary consideration in new construction. Working with the EPA and the respective
state and local regulatory organizations is old hat for almost all U.S.-based companies in the
textile/apparel complex. But other than nonwovens and specialty applications, few new textile
facilities are being built in the United States.Thats one reason we dont design plants to be in
production for 50 years anymore, said one industry insider who preferred to remain unnamed. Despite
all the advances in automation and production speed, textile manufacturing is still a
labor-intensive process. The industry, to be competitive on a global basis, has to go to wherever
the labor is available. Years ago, it migrated from the Northeastern sector of the United States to
the South. Now it is moving to Mexico and Latin America. I believe we have a specific window of
opportunity there, however. In the not-too-distant future, basic manufacturing will move again,
essentially to wherever there is a ready supply of relatively skilled, inexpensive labor. So it
really doesnt make a great deal of sense to build a plant to last 100 years.Environmental factors,
depending upon location, might be less stringent in developing nations than in the United States,
but major U.S. mills tend to build plants in other countries to specifications similar to those for
domestic facilities.Air quality and wastewater treatment standards might be similar, but the
process of getting required permits and approvals can be substantially different.Mexico is
well-known for its bureaucratic, presentation-oriented approach, according to several mill
executives. One mill reported it took more than a year to get the environmental impact statement
approved, even though the mill used the same waste treatment, air abatement and hazardous waste
disposal procedures that generally win quick approval in the United States.In addition, the same
mill reports construction practices in Mexico that differ depending upon region.You find that
contractors in the northern part of Mexico generally work much the same way as you would expect in
the United States, using a lot of heavy equipment and mechanization, one executive said. The
further south in Mexico you go, however, the more labor-intensive construction becomes. In the
southern part of the country, if you need a ditch that is 10 feet wide and 40 feet long, you might
see people in the trench with shovels. Conversely, you would never see that in the United States or
in northern Mexico.Water is a particularly big issue in Mexico because all water is federally
owned. A company building a plant has to dig its own wells, pay for all water pumped out of the
well and then pay again when treated water is returned.From a cost perspective, U.S. mills say the
only significant difference is in labor. Materials cost about the same in the United States and
Mexico, and scheduling is very similar.Regardless of location, however, todays plants are built to
provide optimum conditions for high-quality manufacturing. High-speed equipment exponentially
increases dust and air pollution. Processes that might require one kilowatt of power a few years
ago might now require 10. More air exchanges per hour are necessary. Power delivery has to be
cleaner to provide uninterrupted operation of sensitive electronic controls.Infrastructure Tax
DeductionsOur tax rules go to quite some length to define and limit the tax deductions for the
infrastructure of your textile operation or business. Ordinarily, neither the buildings that house
the operation nor what tax rules refer to as structural components qualify for fast tax
write-offs.The term structural components includes such parts of a building as walls, partitions,
floors and ceilings, as well as any permanent coverings such as paneling or tiling, windows and
doors. It rarely includes machinery required to meet temperature or humidity requirements essential
for the operation of other machinery or for materials processing.Machinery will meet a sole
justification test even though it may provide employee comfort as well or serve, to an
insubstantial degree, areas where such temperature or humidity requirements are not essential. A
good example would be the air conditioning and humidification systems installed in many textile
plants to maintain temperature or humidity within the narrow optimum range that is critical in
processing particular types of yarn or cloth.Squeezing Faster Depreciation DeductionsUntil
recently, textile operations and businesses could choose faster or slower depreciation methods for
their machinery and equipment. Similar choices did not exist for buildings and their structural
components, which were required to be depreciated over 39 years using the slow, straight-line
method of depreciation.Today, the Internal Revenue Service (IRS), in IRS Legal Memorandum
199921045, provides guidance to building owners who want to maximize up-front depreciation
deductions. Now, some of the assets installed in a building can be written off via accelerated
depreciation over five or seven years (or even expensed immediately under the Section 179,
first-year expensing rules) if they are not structural components.MACRS DepreciationUnder the IRSs
basic depreciation system, MACRS (modified asset cost recovery system), nonresidential real
property is depreciated over 39 years using straight-line depreciation. By contrast, so-called
Section 1245 property is eligible for much faster depreciation (e.g., five years) using the
200-percent declining balance method.Under MACRS, a textile operation generally cannot break up a
plant building into components and write off each separately. However, according to the U.S. Tax
Courts decision in the case of Hospital Corp. of America vs. Commissioner (109 TC 21 (1997), if
property would have qualified as tangible personal property for investment tax credit purposes
under pre-1981 tax laws, it will also qualify as tangible personal property for MACRS purposes
today.Assets Eligible For Quick RecoveryThe Tax Court concluded that Hospital Corp. could
depreciate, over a five-year period, a percentage of the electrical systems, measured by electrical
load, that was allocable to hospital equipment as opposed to building operation and maintenance.
Also eligible for quick write-offs were many components, at least to the extent that they were for
a function or equipment unrelated to the operation or maintenance of the building, regardless of
the fact that the equipment was permanently installed.When a structure is built to house a
restaurant, for example, that part of the cost of its electrical distribution systems that is
allocable to the restaurants operation (e.g., refrigerators, freezers, food preparation equipment)
would be eligible for five-year accelerated depreciation. Similarly, the owner of a building
housing extensive computer operations should be able to claim a quick write-off for the portion of
the electrical systems relating to the computers. Obviously, an engineer would have to certify the
percentage of the electrical load allocable to non-building operation or maintenance.The IRSs legal
memorandum validates the Tax Courts central conclusion regarding whether assets installed in a
building should be eligible for fast recovery under MACRS. Unfortunately, that memorandum also
states no bright line test exists for determining if property is a structural component or tangible
personal property.The IRS doesnt have a test for separating structural components from the tangible
personal property supporting your textile operation. However, the faster write-offs now available
for that personal property make the effort of following the IRSs advice well worthwhile.By Mark E.
Battersby
Editors Note: Mark E. Battersby is a tax and financial advisor from Ardmore, Pa. He writes a
weekly farm taxes column syndicated in 45 newspapers and a topical tax column carried by several
trade magazines and more than 25 business publications.

August 2000

The Hosiery Associations (THA), Charlotte, N.C., annual convention in September will feature a
variety of seminars on issues affecting the legwear industry. The event will provide a forum in
which hosiery professionals legwear manufacturers, retailers, business lawyers, and e-commerce and
finance networks can share information and provide mutual support.Some questions that will be
addressed during the show include: How will my sourcing operations be affected by the removal in
2005 of textile quotas for the members of the World Trade Organization (WTO) Is my company prepared
to get involved in e-commerce What are the ready-to-wear fashion trends predicted for Fall 2001,
and how can my business capitalize on them What steps should I take to evaluate the worth of my
business for a sale, merger, acquisition or family transferFor more information on business
sessions and events scheduled for the convention, visit the associations site,
www.hosieryassociation.com.

August 2000

Synthetic Industries, Chattanooga, Tenn., and Shaw Industries, Dalton, Ga., were awarded a U.S.
patent for the invention of SoftBac carpet, a collaboration of both companies.The patent was given
for a composite fabric consisting of a woven scrim combined with a fiber batt. It also covers the
method for manufacturing the carpet. The object of the invention is to provide a modified secondary
carpet backing that will increase the delamination strength and dimensional stability of the
carpet, as well as block the latex or other adhesive from exuding out of the back of the carpet.The
physical properties of SoftBac carpet are second to none, said Carey Mitchell, director of
technical services, Shaw. To date, we have yet to find a carpet system that offers the same
dimensional stability, is as easy to work with and that is as consumer friendly as SoftBac.

August 2000

Industry InfrastructureBy Jim Phillips, Executive EditorCompact And Efficient
Air filtration developments save space, reduce dust and increase product
quality.Compliance with OSHA dust standards remains a major expense in both construction of
new textile plants and expansion and retrofitting of older ones, according to executives of air
filtration systems suppliers. The good news, however, is that the hit on space, cost and efficiency
is steadily declining.The trend in air filtration is toward smaller units that outperform their
gigantic predecessors, cost less to install and require less downtime for maintenance.In truth,
OSHA has probably done the industry a favor, said W. Brad Carr, vice president, textile engineering
sales, Luwa Bahnson. Modern air filtration systems eliminate so much particulate matter that
product contamination is not nearly the issue it once was. The efficiency of air filtration systems
in American textile plants has had a positive impact on product quality.Luwa Bahnson,
Winston-Salem, N.C., is one of the major companies in the United States that design and manufacture
complete turnkey air filtration systems, as is Pneumafil, in Charlotte, N.C.We are designing new
systems that offer up to 50-percent space savings over conventional systems, said John Stonestreet,
Pneumafils sales manager. These smaller systems provide greater efficiency than much larger,
older-style systems. We have some applications, for example, that outperform older systems that use
tandem design.Air Filtration ChallengesThe challenge before air filtration system design engineers
has not been solely to keep up with OSHA standards. New, faster production equipment high-speed
cards, spinning frames, looms has significantly increased the amount of particulate matter that
must be removed from ambient air.Its not a linear progression; its exponential, Carr explained. It
is amazing the amount of dust and waste produced by modern machinery. A rule of thumb is that a
typical mill 20 years ago would have required 20 air exchanges per hour (AC/H) to keep particulate
matter within limits. Ten years ago, the same mill would need 30 AC/H. Today, with current OSHA
dust level requirements and the speed of new production equipment, that same mill would need 45-55
AC/H.

OSHA requirements now allow a maximum respirable dust concentration in most workplaces of 133
micrograms per cubic meter, Carr said.We have to look at several things in accomplishing our goals,
he continued. How you supply the air can be as important to quality and cleanliness as how you
remove waste.For example, Luwa Bahnsons LoomSphere® system, a patented system designed to provide
optimum humidification for the weave room, establishes and maintains an exact and constant
environment around each loom. A precise airflow is designed to bathe each loom in a tightly
controlled environment of cool, humid and clean air. The conditioned air flows through the entire
warp sheet and preconditions the warp beam. As the air flows through and around the loom, the yarn
is strengthened by the moisture gain while the dirt and fly are carried to the return air openings
on the floor, where they are removed.Carr said the LoomSphere system results in reduced energy
costs, reduced maintenance, less capital cost and, most importantly, clean and precisely controlled
conditions at the loom.The advantage to this system is that it is a gentle flow of air over the
process, Carr said. It doesnt create turbulence, which would stir up the fiber fly and dust.For
ambient air filtration in large, open spaces, Luwa Bahnson, like Pneumafil, has developed efficient
systems that occupy a fraction of the space needed by conventional drum filters.We have our Sonic
Micro Filter, which is ideal in installations where space is at a premium, said Carr. It requires
less room than a conventional drum- and panel-type filter, requires less pressure drop, or energy
usage, than roll-media filters and automatically cleans itself, which eliminates labor required to
change disposable roll media.The ambient air return in the Sonic Micro Filter is conducted axially
to the rotary filter screen. The proprietary filter mesh and flow rate velocity are selected in
accordance with the type of application. A layer of fiber and dust is built up on the fine-mesh
screen, which increases filtration efficiency. At a selected pressure drop, the filters are cleaned
until the pressure drop is lowered to a selected set point. The waste deposited on the filter
screen/media is removed by means of a near-sonic velocity impact air nozzle in conjunction with a
catching suction nozzle. The high mass flow/high impact air nozzle dislodges the waste to
regenerate the filter screen/media.

Luwa Bahnson, as well, manufactures an Air Bell system for circular knitting applications,
which the company claims can eliminate fiber defects by as much as 50 percent. The Air Bell system
controls the airflow volume, condition and pattern to optimize efficiency. The distribution of air
provided by the Air Bell system, Carr said, sufficiently prevents fluff from entering the bell. The
air current at the feed wheel is strong enough to transport any free-flying fibers that develop.
The fibers are then carried off. This method of control prevents fluff from returning to the
knitting machine.Pneumafils Everclean Rotary Pleated Belt Filter, also a patented filtration
system, combines high-capacity pleated-membrane media with high-efficiency suction cleaning, said
Stonestreet.The Everclean filter consists of a number of filter cells, he said. Each cell comprises
an endless pleated media belt looped between two pulleys. Unfiltered air enters the unit parallel
to the filter cells and passes through the straight sections of the belt loop. Larger fibers
collect on the outer edges of the pleats, and smaller particles build up on the media surfaces
between pleats. The clean air continues between the two sides of the cell into a plenum in back of
the filter and then exits. Pressure drop across the media is constantly monitored. When the high
set point is reached, a cells belt begins rotating around the pulleys, and a stationary suction
plenum underneath the cell is activated. As the belt moves around the lower pulley, the pleats open
up and airflow through the media is blocked, allowing the pleats to be vacuumed clean.We have been
notified by two recent clients that the installation of this filtration system has allowed them to
exceed the OSHA dust test for the first time in history, said Stonestreet. One installation was a
plant expansion, and the other was a retrofit of an existing application.The Everclean system is
designed for production areas from opening through spinning. For weave-room applications, Pneumafil
offers its Automatic Panel Filter (APF).The APF is a self-cleaning filter that installs in a
fraction of the time required for installation of space and conventional drum filters, Stonestreet
said. Air is cleaned as it flows through an arrangement of parallel, hollow filter cells, each
formed by two sets of filter panels. A pressure differential switch or timer activates the cleaning
mechanism, which travels in and out of the space between filter cells. A shuttle device moves the
cleaning mechanism from cell to cell and returns it to the starting position when a complete pass
of the filter panels is accomplished. Filter panels are always cleaned in the same sequence,
ensuring that dirtier cells are cleaned before those with less accumulation. Stripper nozzles
vacuum the filter media until proper pressure is restored. Waste is pneumatically carried to a
disposal unit.Both companies have brought to domestic and export market preassembled filtration
systems that offer substantially reduced engineering, labor and installation costs.The Luwa Bahnson
Insta-Filter, a complete primary and secondary filtration unit, is used as part of a complete air
engineering solution. Contaminated air flows horizontally through a baffle system to equalize and
straighten air flow. Next, the air flows through a Sonic Micro Filter or Rotary Pre-Filter to
remove lint. The Rotary Pre-Filter provides preliminary filtration of air streams heavily charged
with waste. Air then passes through a Luwa Bahnson Multi-Drum Vac® (MDV) filter to remove
microdust. The MDV provides filtration of fine particles. Both lint waste and microdust waste can
be automatically removed and compressed for easy handling.This is a very simple filtration system,
said Carr. It is ideal for export because it doesnt require a lot of engineering and installation
expertise on-site. By assembling much of the system before it is shipped, a lot of add-on costs are
eliminated.The Pneumafil Rotary Pleated Belt Filter is preassembled on a steel base and prewired,
including controls, Stonestreet said.Both Pneumafil and Luwa Bahnson provide primary and secondary
filtration systems, as does Industrial Air Inc., Greensboro, N.C.Industrial Air offers filtration
systems, ranging from integrated air systems to air washers, fiber and waste separators, custom
HVAC systems, as well as bag, drum and roll filters.Our main focus, as is that of the entire
industry, is to provide our customers with the most efficient means to meet OSHA dust standards,
said Allen Hunter, president, Industrial Air. We offer complete, turnkey solutions to make this
happen.Among the newest offerings from Industrial Air is the S Series drum filter, according to
Hunter. The S Series filter is constructed of perforated steel panels bolted together to form a
cylindrical horizontal rotating drum. The arrangement, Hunter said, allows even air distribution
across the fabric filtering media. When bolted together in multiple sections, these panels form a
rigid cylindrical truss member that eliminates the need for a continuous center support shaft,
which facilitates maintenance. The drum is cleaned by a series of vacuum nozzles located on the
outside of the cylinder, allowing convenient media inspection. Industrial Air has also introduced a
new Hi-Vac sleeve receiver that has 400 percent more screen area than standard 30-inch flat screen
receivers, Hunter said.Replacement media for many filtration systems are proprietary, according to
Pneumafils Stonestreet. However, one new venture, FiltersRx.com, a division of Lifetime Industries,
now makes replacement filters available through the Internet.For More InformationLuwa Bahnson3901
West Point Blvd.Winston-Salem, NC 27103(336) 760-3111
www.luwabahnson.com Pneumafil
Corporation4500 Chesapeake DriveP.O. Box 16348Charlotte, NC 28297(704) 399-7441
www.pneumafil.com Industrial Air
Inc.428 Edwardia DriveGreensboro, NC 27409(919) 292-1030

August 2000

Wet Processing UpdateATI Special ReportpH Control In The Dyeing Of Polyamide
DyStars Optidye N program calculates optimum conditions for dye penetration and shade
stabilization.Uptake of acid and metal-complex dyes by polyamide is temperature-dependent. The
fiber takes up the dye at temperatures above the glass transition point because the segments in the
polymer chains become more mobile at higher temperatures. The fibers thus open and allow the dye,
which is attracted to the positive charge on the amino end groups in the fiber, to penetrate the
polyamide. It is then bonded to the fiber through intermolecular forces. At the end of the dyeing
process, a thermodynamic equilibrium is established between the dye dissolved in the liquor and the
dye that has diffused into the fiber. The relationship between the dye concentration in the liquor
and on the fiber is roughly described by the well-known Langmuir and Nernst isotherms.A finite time
is required to achieve this state of equilibrium. The time required depends on the substrate, the
dyes and the process parameters. This process can be described by the laws of dyestuff diffusion.
Applying these physical chemical principles in conjunction with practical experience shows the
dyeing process.Systematic OptimizationThere are two established methods of dyeing polyamide with
acid and metal-complex dyes: the constant-pH process and the pH-sliding process. While the
constant-pH process ensures that the dye exhausts onto the substrate by raising the temperature,
the pH-sliding process achieves exhaustion by a combination of raising the temperature and reducing
the pH.In the constant-pH method of dyeing polyamide (Polyamide S process), the aim is to produce
dyeings that are as level as possible from the outset and have good reproducibility.

Level application of dyes, particularly at the start of the dyeing process, can be ensured if
all of the dyes exhaust onto the substrate uniformly. This is what is referred to as their
combination behavior (See right). It can be achieved in two ways. The first is to select suitable
dyes with good combinability. If this is not possible on coloristic grounds or because of the
fastness properties required, a second method can improve the combination behavior of some dyes by
using an auxiliary with affinity for the dye. The optimum concentration of such auxiliaries depends
on the type of dye, dye concentration and the auxiliaries used. The combination behavior of the
dyes may deteriorate if the amount of auxiliary exceeds the optimum level.To ensure good levelness,
the dyebath must contain enough dye to allow sufficient migration. However, if bath exhaustion is
too low, too much dye is wasted. As well as raising dyestuff costs, which are relatively low
compared with the overall process costs, this alters the final shade and thus impairs
reproducibility. A low pH increases bath exhaustion and reduces migration, while an increase in the
concentration of an auxiliary with affinity for the dye has the opposite effect. The pH therefore
needs to be optimized to ensure optimum bath exhaustion. At the same time, the strike rate (i.e.,
kinetic properties) plays a major role in regulating the dyeing process. During the heating-up
phase, the dyes exhaust onto the fiber in a given temperature range. This is known as the critical
temperature range. The beginning and end of this range are indicated by TStart and TEnd (TStart
must not be confused with the temperature at the start of the dyeing process). The optimum heating
gradient depends primarily on the unit used.To ensure good penetration of the fiber and thus
stabilize the shade and improve fastness, a diffusion phase is required after exhaustion of the
dyes. The time required for this depends on the substrate and diffusion properties of the dyes. In
practice, the diffusion period is often unnecessarily long. This raises process costs and can
damage the goods. Optimum conditions can be calculated using DyStars Optidye N computer program,
which includes both the underlying theory and the necessary dyestuff data.The Optidye N ProgramThe
Optidye N program contains the formula required for systematic optimization of polyamide dyeing
(See below). It contains data on the properties of DyStar products and a number of auxiliaries.
Users enter details of the recipe, dyeing units and substrate for each batch. The program then
calculates the optimum dyeing profile, the pH required to achieve average bath exhaustion of
approximately 95 percent and the auxiliary concentration required to ensure optimum compatibility
of the dyes. Alongside the recipe data, details of the substrate are very important.

Two parameters are required to describe the dyeing properties of polyamide to be dyed in the
constant-pH process. The V value shows how quickly a standard dye exhausts onto the substrate. The
fiber saturation value (SF value) shows the maximum amount of dye that can exhaust onto the
substrate. Any dyehouse laboratory can determine these values by carrying out a few dyeings. Values
determined in bulk conditions vary between 1 and 3 for SF and 0.2 and 5 for V. For a typical recipe
with Telon A dyes, the following exhaustion ranges may be calculated on the basis of the SF and V
values given above.For V=0.2 a range of T
^Start=74°C and T
^End=102°C is calculated. To save time, the bath can be heated to 74°C as fast as the
equipment allows, without any risk of unlevelness. By contrast, for V=5, the final temperature T
^End=31°C, while T
^Start would be below the normal water temperature (theoretically below 0°C).
Consequently, heating the bath too quickly at the start would entail a risk of unlevelness. A dwell
time at the start of the process (e.g., 15 minutes at 20°C) can reduce this risk but not eliminate
it entirely. Moreover, a higher starting pH would be required. In other words, a pH-sliding process
would have to be used. Using a pH-sliding process, the bath could be heated rapidly from 31°C.
These examples show how effective optimization of the dyeing profile can be. The next section looks
at the progress made on the basis of these theoretical findings.Extending The Polyamide S ProcessAs
we have seen, it is necessary to regulate bath exhaustion to ensure the correct level of migration.
In the constant-pH process, the aim is to achieve final bath exhaustion of around 95 percent.
However, to increase reproducibility, bath exhaustion of nearly 100 percent would be ideal. This
can be achieved by reducing the pH. Similarly, if the V value of the substrate is very high and the
strike rate cannot be controlled solely via temperature, a modified version of the constant-pH
process is required. The pH-sliding process was developed from the constant-pH process specifically
for critical shades and problematic units and substrates. This process uses a combination of
temperature rises and a reduction in the pH during dyeing to control exhaustion of the dye. Under
standard dyeing conditions (pH 7), the amino end group and the carboxyl group are protonated. In
other words, viewed from a distance, this material has a positive electrical charge. A negatively
charged dyestuff molecule is therefore attracted to the PA and tries to react with it. Raising the
pH in other words, reducing the concentration of H
⁺ ions deprotonates the carboxyl group, leading to a negative charge. The fiber thus
takes on a neutral or negative charge, and the dyestuff molecules are not so keen to react with
it.Therefore, pH plays a major role in the exhaustion of the dye from the liquor onto the surface
of the fiber and in the diffusion of the dye in the fiber. The optimum pH range required for the
pH-sliding process depends to some extent on end groups in the fiber. Practical trials have shown
that a pH
^Start that generates bath exhaustion of around 70 percent is most suitable. Since the
reproducibility of a dyeing is best at 100-percent bath exhaustion, wherever possible the pH should
be reduced to a level where this is achieved. pH
^End thus depends on the substrate, dyeing recipe and auxiliaries used. This value can be
calculated using the Optidye N program. It is about 3 points below pH
^Start and 0.5 points below the pH used for the constant-pH process.

To optimize the pH-sliding process, we look at three different ranges in which the pH can be
reduced (See right).Depending on requirements (i.e., the level of difficulty), three different
points are recommended for the addition of the acid. In the process shown in Figure 4 as the most
rapid method, the pH is reduced as soon as the temperature reaches the start of the critical range.
This method is suitable for relatively uncritical conditions. The dyeing time at T
^max is then equivalent to the diffusion time in the constant-pH process. The critical
temperature range can be passed through faster because the pH at the start of the process is above
the level used in the constant-pH method, allowing for more level dye uptake.In the second method
illustrated here (the universal method in Figure 4), which has proved reliable in practical trials,
the pH is reduced when the temperature reaches the end of the critical range. This generally
ensures an optimum balance between dyeing time and reliability.The third method, which is shown in
Figure 4 as the most reliable method, should be used only for very difficult shades such as
turquoise. In this method, the pH is not reduced until the temperature reaches T
^max. The low level of bath exhaustion at the higher initial pH value is utilized for
migration of the dyes. Compared with the constant-pH method, the dyeing time at maximum temperature
is increased by the length of time required for dosing.Regrettably, the most suitable of these
three methods can only be determined empirically at present, as no mathematical formulae are
available. Alongside the migration properties of the dye, other major influences are the equipment
used and the composition and pH-dependence of the polyamide.Constant-pH Vs. pH-Sliding MethodsThe
two methods used to dye polyamide are the constant pH method and the pH-sliding method. The
parameters used in this illustration were calculated on the basis of the same recipe with the aid
of the Optidye N program. The unbroken curves show the temperature profile for each method (the
gray curve shows the pH-sliding process and the black one shows the constant pH method), while the
broken line shows the pH profile. The fiber saturation value of the substrate used in this example
is SF=2.0, and the strike rate is V=1.2. Both curves show that the liquor was heated as fast as
possible up to the critical range. Since virtually no dye is exhausted onto the fiber during this
heating phase, the highest possible heating gradient should be selected to save time. The critical
temperature range depends on the pH; it is slightly higher for the pH-sliding process than for the
constant pH process. A higher heating-up rate can be selected in the critical temperature range
when using the pH-sliding method than when using the constant pH method. Once the temperature has
reached TEnd, at which point exhaustion of the dyes is completed or the desired level of bath
exhaustion is achieved, depending on which method is being used, the heating rate is increased
significantly. The temperature is held at the maximum point until full penetration of the fiber is
achieved. This is necessary to stabilize the shade and achieve the desired fastness properties. The
dwell time at maximum temperature may be longer in the pH-sliding process if the maximum
temperature is used for part of the pH-sliding phase.The amount of auxiliaries needed to optimize
the combinability of the dyes varies in the examples shown here. Virtually no auxiliary is required
for the constant pH process (the optimum concentration is 0.2 percent), whereas 0.6 percent is
required for the pH-sliding process.Although the pH-sliding takes longer and requires buffers and a
control unit, it has proved effective, especially for shades where it is difficult to achieve level
dyeings. The process also improves reproducibility because it raises bath exhaustion. Setting The
pHChanging the pH during the dyeing process is a method that has been used since the 1970s to dye
carpets on winch becks, for example. Methods such as the Telomat and Dosacid processes are
well-established. Since the pH is an inverse logarithm of the concentration of H+ ions, it is often
difficult to regulate automatically. Methods used to control the pH during dyeing include pH
buffers, acid or alkali donors and automatic control and regulation units.While a pH buffer
maintains a constant, predefined pH, acid and alkali donors alter the pH as the temperature rises.
Automatic pH measuring and control units can be used for the constant pH and pH-sliding methods.
Moreover, they are often used to monitor the pH and thus control the process. However, in the past,
such units have not been stable enough to become established. A modern pH-control unit is expected
to meet the following requirements:

• robust technology with low maintenance requirements;
• user-friendliness;
• automatic calibration;
• long-lasting electrodes; and
• simple connection to dyeing units

pH-FiT, a pH measuring and control unit developed by Thies, SETEX and DyStar, has a modern
SETEX 737 control unit with integrated fuzzy logic to match the measurements taken to ideal values
using predefined rules. To make it easier to use, the unit has an automatic calibration device,
which contains buffer solutions and a KCl solution to protect the electrodes. pH-FiT is available
either as an integral system built into dyeing units or as a mobile unit, which can be connected
and operated in the same way as well-known alkali dosing units such as Adcon (automet).The pH
sensor (electrode) is built into a bypass parallel to the liquor pump. To prolong the life of the
electrodes, they are only placed in the liquor to take measurements. The bypass has a back cooling
system that cools the liquor to 80°C. This is also designed to prevent wear of the electrodes. In
the mobile unit, the acid or alkali is added via a dosing pump. If several pH-FiT units are
installed in the same plant, it makes sense to pump the chemicals in a closed-system circuit with a
dosing valve for each dyeing unit.To demonstrate how the Polyamide S process can be used to
optimize the pH-sliding process in conjunction with a pH-FiT unit, Figure 3 shows exhaust samples
taken from the dyebath after beam dyeing of a polyamide taffeta fabric with Supranol and Isolan
dyes. To achieve an optimum dyeing profile, the starting temperature for the critical range was
calculated at 48°C, while the final temperature was calculated at 88°C. Since the dyeing involved a
critical shade with high-molecular dyes, the reduction in pH was selected to ensure maximum
migration (i.e., the pH was reduced after the critical temperature range). The optimum pH range in
this case is 8.5 to 5.6. A statistical evaluation was made of the reproducibility of bulk dyeings
performed using the pH-sliding method and the Polyamide S process on the basis of approximately 300
batches dyed on the jet. After optimization of the process, the optimized and non-optimized batches
were compared.Process times were reduced by 27 percent per batch, mainly due to a 65-percent
reduction in the need to correct faulty dyeings. The use of acetic acid instead of an acetate
buffer cut chemical costs by 48 percent. Altering the chemicals used also reduced effluent
contamination, for example, but lowered the COD.

The Compudye SystemOptimizing the pH-sliding process through the Polyamide S process is only
one aspect of our approach to modern dyeing methods. Following successful application of the
Optidye N PC program, where certain data such as the recipe have to be entered manually, it is far
more effective for routine work to automate both these inputs and the transmission of the dyeing
parameters calculated to the control units. Dyehouses often have a host computer system on which
the servers and PCs depend and which is responsible for coordinating routine tasks. The Optidye N
program may use data already in the system. Alternatively, the host system may require data from
the Optidye N program. Once the dyeing recipe has been calculated, data on the recipe, substrate
and equipment are transmitted to the Optidye N program to optimize the recipe. In the simplest
case, this takes place manually. In a fully automated dyehouse, the data would be transferred
automatically via a network. The Optidye N program would then pass the relevant optimized recipe
parameters on to the control unit on the dyeing machine which needs data like T
^Start, T
^End, heating-up rate, pH range, pH reduction time, etc. and to the color kitchen, which
needs data on the dyes required and the optimized additions of auxiliaries.For more information on
pH control research, contact Karl-Heinz Michel, DyStar, at 49 69 2109 2734.

August 2000

3M, St. Paul, Minn., is phasing out
and finding substitutes for the perfluorooctanyl sulfate (PFOS) chemistry used to produce certain
repellents. Among the affected product lines are many Scotchgard products used on textile products
including carpets and upholstery fabrics.

Citing increasing attention to the appropriate use and management of persistent materials,
Dr. Charles Reich, executive vice president, Specialty Material Markets, said, “While this
chemistry has been used effectively for more than 40 years and our products are safe, our decision
to phase out production is based on our principles of responsible environmental management.”

In a message relayed through the Carpet and Rug Institute, Dalton, Ga., 3M stated, “…you can
continue to sell all of your current products treated with 3M Scotchgard protection under the
existing labels.”

Sophisticated testing capabilities have detected PFOS broadly at extremely low levels in the
environment and in people. While existing scientific knowledge indicates that its presence at these
levels does not pose a human health or environmental risk, the Environmental Protection Agency
(EPA) indicates a potential long-term risk could be associated with its use.

“EPA will work with the company on the development of substitutes to ensure that those
chemicals are safe for the environment,” said EPA Administrator Carol M. Browner. “3M deserves
great credit for identifying this problem and coming forward voluntarily.”

July 2000

The U.S. Department of Commerce trade
and economic data for the first quarter of 2000 show that textile and apparel exports totaled $4.4
billion, up 5.4 percent over the same period of 1999, while imports for the first quarter reached
an all-time high, totaling 7.8 billion square meters equivalent (sme) or $18 billion.

The increase in textile imports has been influenced by the three-year-old Asian financial
crisis on one hand and by the North American Free Trade Agreement (NAFTA) on the other, according
to ATMI President Roger W. Chastain. Regarding the surge in Asian imports, he cited increases of 44
percent from Pakistan, 32 percent from Thailand, 25 percent from Bangladesh and 14 percent from
China.

Helping to balance the increased imports from Mexico, at 17 percent, and Canada, at 21
percent, was a reciprocal increase in exports, primarily of fabric and cut pieces, to those two
countries totalling 15 percent.

“Unfortunately, we have not had that kind of success in exporting to other countries around
the world because many markets are closed to our exports,” said Chastain. “All the U.S. textile
industry asks is that it obtains its fair share of access to world markets so it can compete on a
level playing field where everyone plays according to the agreed-upon rules.”

Chastain also commented on the potential negative effects of the U.S. granting of permanent
Normal Trade Relations (NTR) to China and the phaseout of quotas against Chinese textiles and
apparel upon China’s entry into the World Trade Organization (WTO): “This makes it imperative that
we take advantage of new opportunities with our Caribbean partners under the just-passed Caribbean
Basin Initiative (CBI) trade enhancement legislation, especially prior to 2005 when all of the
quotas will be removed.”

Commenting on other economic news related to the textile industry, Chastain said, “After
many months of difficult times, we are starting to see improvement in some key areas, such as fiber
consumption and new textile orders.”

Consumption of fiber on the cotton spinning system increased 5.7 percent in the first
quarter of 2000, the first quarterly gain since first quarter 1999. However, the total consumption
of 1.6 billion pounds, excluding fiber consumption in carpet, woolens and worsted, and some
industrial uses, was still 9 percent below first quarter 1999 levels.

New textile orders rose more than 3 percent in the first quarter of 2000 from the previous
quarter. This represents an increase of nearly 7 percent over the first quarter 1999. Unfilled
orders in March 2000 were 3.6 percent above March 1999 figures.

July 2000

The Belgian weaving machine
manufacturer Picanol and the Radici Group, the Italian conglomerate which includes the
manufacturers Somet and Vamatex, have come to an outline agreement to acquire Fimtextile, the
Italian producer of cam motions and dobbies. Negotiations are also underway with a financial group
which is interested in joining this new venture.

The current acquisition initiative is being taken in order to preserve the variety of
products offered by Fimtextile, whose survival has been threatened by the worldwide recession in
the textile machinery industry. Currently, the Radici Group is its largest customer, and Picanol
has entrusted certain projects to Fimtextile for some time. It is anticipated that other
manufacturers will also be interested in this new company.

Details of the agreement will be worked out in the next few weeks.

July 2000