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Bonding and web forming technologies.


a diversity of web formation and bonding technologies continue to propel nonwoovens into a variety of end use markets; synopses of various technologies describe the great potential for different applications

The Melt Blown Process: Its Role In Filtration

The melt blown process is an extremely versatile process that produces a microfine fibrous web directly from thermoplastic resin.

Melt blown filter media has been very successful in penetrating and gaining sizable market share in several filtration applications, such as surgical and industrial face masks, pleated micron rated cartridges, micron rated bags, coolant filtration and other filtration applications.

The total annual worldwide market volume for melt blown media used in air and liquid filtration applications has grown to exceed 20 million pounds.

The success of the melt blown media to penetrate these filtration applications is due to the capability of the process to produce microfine organic fibers at a relatively low cost. The average fiber diameter of melt blown webs range from 1-10 microns, with most melt blowns used in filtration applications having a diameter of 2-4 microns. These fiber sizes compare to conventional nonwovens processes that are composed of fibers in the range of 1-3 denier (approximately 13-22 microns).

The finer fiber size increases the number of fibers and surface area in a given volume and hence increases the filtration efficiency. The filtration efficiency of the melt blown media can be further enhanced through charging of the media, which significantly enhances the filtration efficiency without changing the pressure drop of the media. Charged melt blown media that exhibit stability in high humidity and long term shelf life under normal storage conditions are being commercially produced.

In addition to having high efficiency, the melt blown media are composed of synthetic polymers and can be produced without the addition of chemical additives or binders. These synthetic polymers are considered to be harmless and tend to have low shedding properties. Due to these characteristics, melt blown media have been successful in replacing glass and other filtration media due to fears concerning the use of glass or due to problems of fiber shedding or chemical contamination of the end product.

Background Of The Melt Blown Process

The development of the melt blown process was initiated in 1951 by the Naval Research Laboratories in an effort to develop organic microfibers. This research resulted in the development of organic microfibers on lab scale equipment. This initial research and development work was continued by Exxon in the mid-1960s, which resulted five years later in the first large scale pilot production process to produce melt blown fibers. Exxon continued its research work on the process and began licensing the technology to several companies in the 1970s. There are currently at least 60 production lines worldwide, with the majority operating under Exxon's license.

Melt Blown Properties

The melt blown process is an extremely versatile process, capable of producing filter media of widely different polymer compositions, weights, thickness, pore size and fiber size. Therefore, an almost infinite variety of grades could be produced to target a variety of filtration applications.

In theory, the melt blown process is capable of extruding and forming a web from any thermoplastic resin. The polymers that are generally used on a commercial basis are polypropylene, polyester (PET, PBT, PCT), polyethylene, nylon and polyurethane.

Polypropylene resin is the most widely used resin in commercial melt blown applications and in most filtration applications. This is to a large extent because the manufacturers of polypropylene resins have devoted sufficient research and development efforts to tailor the polypropylene resin specifically for the melt blown process. In addition, this resin is relatively inexpensive compared to other resins, is easily blown into a small fiber diameter and provides a high degree of chemical resistance and purity. The major disadvantage of polypropylene is that with melt temperatures in the 350 F range, it is not very heat resistant.

The next most widely used resins in filtration applications are polyester, which are used primarily in applications requiring higher temperature resistance, since polyester resins have a melt temperature in a range of 450 F. Although polyester resins have not been as well developed for the melt blown process, they can be readily processed through the melt blown process, producing webs with fiber diameter sizes int he 3-4.5 micron size range.

Polyethylene resins are generally not used in filtration applications. However, these resins are expected to gain wider use in melt blown products designed for medical applications due to their resistance to gamma sterilization, which tends to degrade polypropylene resin.

In addition to melt blown webs produced from pure polymers, it is possible to add various chemical additives by mixing the chemical additives to the resin prior to the extrusion process. Some of the more common additives would be pigment for product identification or aesthetic purposes, wetting agents to rend the product hydrophilic or antistats.

The weights of the melt blown media can be varied between 10-1000 grams sq. meter by varying the line speed. Most of the melt blown media used in filtration range in weight from 10-100 grams sq. meter, since high levels of efficiency can be achieved at relatively low weights.

The thickness and consequently the pore size and void volume of a given weight can also be altered within wide ranges. The melt blown process is capable of producing thicknesses in the range of 3-300 mils and mean pore sizes in the rage of 4-30 microns. The thickness and pore size can be further reduced through the incorporation or area or point bond calendering methods.

Applications for Melt Blown Filter Media

The largest and probably some of the first applications to use melt blown media are in surgical and industrial face mask applications. Surgical face masks are designed primarily to protect the patient from bacterial contamination in surgical operations. These masks are usually specified to meet a bacterial filtration efficiency (BFE) of 95% or greater, with pressure drops usually below three mm.

The melt blown media have almost completely replaced microdenier glass media in these applications, due to the fear of breathing glass fibers migrating or shedding from the media. In surgical face mask applications generally 15-40 grams sq. meter polypropylene melt blown media is used. This melt blown is usually sandwiched between two layers of either a dry laid or wet laid nonwoven, which provide strength to the melt blown and allow the media to be folded or molded into the shape of the surgical face mask.

Disposable industrial masks are used to protect workers in industrial applications. In general, the test requirements of the industrial masks are more stringent than required in surgical masks. The melt blown media are usually 40-60 grams sq. meter polypropylene melt blown, which may or may not be charged media.

HVAC or Ashrae pocket filters are composed almost entirely of filter media formed into several pockets or bags with sewn or welded seams. There is a growing market for HVAC pocket filters composed of 100% synthetic media to replace microfine glass batts.

There is a market developing in the European and Japanese markets for automotive interior cabin air filters. These filters are being developed to remove particles in incoming air. In general, most manufacturers are targeting 95% efficiency in the 1-3 micron range. Melt blown media are being developed to meet these requirements, generally combined with other nonwoven support media.

Pleated liquid mircon rated cartridges are designed to remove particles above a rated particle size from a liquid product, usually in the .5-40 micron range. They are designed with several layers of polypropylene melt blown, usually sandwiched between two or more layers of spunbond as support.

Micron rated vessel bags are designed to filter out particles in the range of 1-800 microns from various liquids. The traditional media used are needled felts of rayon/polyester, polyester, nylon or polypropylene. In the mid-1980s, 3M entered this market offering micron rated bags composed of its "Filtrete" microfiber polypropylene. In the late 1980s, 3M introduced filter bags of multilayered melt blown media. Also in the late 1980s other manufacturers introduced bags composed of felt, polypropylene melt blown media and spunbond nonwovens.

Coolant filtration media is usually used in roll form. The majority of media used is either wet laid nonwovens or spunbonds. Melt blown media are used where higher levels of filtration performance are required.

'S-Tex' Spunbond--A Unique Filtration Media

Spunbond fabrics are widely used in filtration applications, especially those requiring a fabric having good strength. Typical filtration applications for spunbond fabrics are swimming pool pleated filters, coolant oil filters, cotton linter and dust filters in textile mills and support fabrics for HVAC microfine glass media.

Spunbond fabrics perform quite well in these coarse or large particle size filtration applications because they meet many of the nonwoven filtration criteria.

Spunbond fabrics are composed of continuous filaments and are typically made in weight ranges from 0.3-6.0 oz. sq. yard. Because of the continuous filament structure, spunbond fabrics exhibit good strength. Grab tensile strength values range from about 10-20 pounds at an 0.5 oz. sq. yard fabric weight to a high strength of 120-240 pounds at a fabric weight of 6.0 oz. sq. yard. The polymer type and degree of fiber orientation during spinning/drawing and bonding will have a major influence on fabric strength.

Fiber diameter plays a distinct role in filtration performance. The majority of spunbond fabrics produced today are composed of filaments of two to 20 denier, therefore having fiber diameters of 20-55 microns, depending on polymer composition and assuming round filaments. Filaments of this large size are not efficient in removing small micron size particles since then can not be positioned in the web as it is laid down in such a way to create small pore openings. However, spunbond fabrics have been able to partially overcome this, either by increasing the basis weight, by being calendered or by using multi layers of fabrics, either bonded together or not. However, these approaches nearly always result in significant increases in costs.

The Melt Blown Attributes

To achieve finer particle size filtration, for example in the less than 10 micron range, producers must turn to fabrics made with the melt blowing process.

Melt blown fabrics are extensively used in filtration end uses requiring fine to medium particle size separation capabilities. Typical melt blown applications are industrial and medical masks, coolant (aluminum can and rolling mill) filtration, automotive interior air supply filters and cartridge filters for high purity chemicals.

These end uses usually require that the melt blown media be combined with another material, usually a carded web or spunbond fabric, to achieve the necessary strength or stiffness to meet specific application requirements.

The strength properties of melt blown fabrics are significantly lower than those of spunbond fabrics because the melt blowns are composed of discontinuous fibers that in the majority of cases rely on mechanical entanglement for their strength. The grab tensile strength properties of melt blown fabrics usually range between 0.5-1 pound at a 0.5 oz. sq. yard basis weight, to a high of 9-24 pounds at a 12 oz. sq. yard basis weight.

Melt blown fabrics achieve their microfiber size because the polymer is subjected to sub-sonic hot air as it leaves the spinnerett. Fibers have been experimentally produced as small as 0.1 micron in diameter. However, the typical fiber diameter is 1-10 microns, depending on the filtration application it is designed to meet.

The melt blown is well suited to produce products designed to remove ultra to medium (0.1-10 micron particle size) filtration requirements. This is based on the ability to spin very small diameter fiber, therefore increasing the number of filaments in a given media volume and resulting in much smaller pores in the media. However, it must be remembered that this is at the sacrifice of fabric strength.

S-Tex: Bridging The Gap

The S-Tex spunbond process and the products it produces are specifically targeted to help bridge the gap between the typical spunbond and melt blown fabrics available today.

This spunbond technology was developed by Johannas Janfeld at Fiberweb's Sodoca operations in France. This unique spunbond technology produces small diameter, continuous filament fabrics. This attribute, coupled with a carefully controlled laydown procedure, results in significantly improved spunbond web formation. The two properties of excellent web formation and small diameter filaments are the keys to producing a spunbond fabric that can perform in new, more demanding filtration applications.

S-Tex's fiber diameters typically range between 10-40 microns. With fiber diameters in this low range, this spunbond fabric begins to bridge the void left between conventional spunbond fabrics and melt blowns. S-Tex's spunbond fabrics have a basis weight range of 0.15-6.0 oz. sq. yard.

The small fiber diameters in the product do not adversely impact the fabric's strength. In fact, S-Tex fabrics show strength properties normally associated with spunbonds of equal weights. The combination of the fabric's strength and its small fiber diameter size that results in small pore size media enables S-Tex fabrics to substitute for traditional spunbond fabrics used in coarse filtration applications with a lower basis weight. It also allows the fabric to begin to achieve medium particle size filtration performance levels that allow infiltration into melt blown applications while providing strength properties common to spunbond properties.

The attributes that S-Tex fabrics deliver can now possibly be used in industrial protective clothing, medical protective clothing, face mask media (industrial dust and medical isolation), food processing, water taps, vacuum cleaner bags and battery separators.

The S-Tex manufacturing technology employs a new fiber laydown and distribution system. This enables the process to provide excellent uniformity, filament diameters between 10-40 microns, basis weight ranges from 0.15-6.0 oz. sq. yard and a selection of polymers (polypropylene, polyester and nylon).

Demand for high performance filtration media presents a tremendous opportunity for spunbond fabrics demonstrating the filtration efficiency approaching micro to fine fiber webs, as well as processing strength and dimensional stability of traditional spunbonds. The S-Tex technology and its fabrics could perhaps provide the next generation of spunbonds promoting high filtration efficiency and strength employing a new fine fiber continuous filament spunbond technology.

Therefore, it can begin to bridge the gap left between spunbonds and melt blown fabrics with filtration properties needed to meet both current and developing filtration demands.

Trends In Hydroentanglement

Hydroentangled fabrics have been one of the fastest growing categories of nonwovens in recent years. Some of the best selling of these fabrics are characterized by soft hand, excellent drapability, breathability and strength. Currently commercial fabrics range in weight from 0.5-4.0 ozs. sq. yard. Prices range from $.10-5.00 sq. yard. The highest volume is at about 2.0 ozs. sq. yard for $.30 sq. yard.

The hydroentangled fabrics business, like many nonwoven fabric categories, is facing a dynamic market and a challenging future. Forecasts for growth in the 1990s range from 3-12% annual rates. Many uncertainties are reflected in that range of projections, with a series of challenges facing the industry of the future.

* Alternate technologies. Several high volume hydroentangled fabric applications, such as surgical gowns and drapes, face continuing challenges from alternate technologies, such as film-based and melt blown composite fabrics. Significant effort is required to continuously improve product performance and cost effectiveness in order to remain the preferred fabric for these applications.

* Environmental concerns. User perceptions about the environmental impact of disposables has renewed interest in reusable alternatives in some applications. More users are requiring environmental impact assessments of both disposable and reusable products and systems. Users are trying to strike a balance for themselves between the utility and performance of the products they use and the total system environmental impact of those products. Because reusables are assumed by many to have less environmental impact, the burden of proof rests on producers of disposables.

* Cost and size of new capacity. To add cost-effective hydroentangled fabric capacity to support growth of existing customers and position to supply new applications requires large steps of investment. Du Pont's new line, which started up in the fall of 1990, cost about $40 million. This line increases world capacity for hydroentangled fabric by about 30%, more than is needed for several years. With this addition, world capacity is about 1.1 billion sq. yards. This puts renewed energy into developing new applications for the technology.

Evolving Business & Marketing Strategies

* Commitment to Europe and Asia. Much of the growth in hydroentangled fabric use is forecast in Europe and Asia. Some nonwovens producers in those areas have installed small, commercially available equipment to make hydroentangled fabrics for market development work and specialized small applications. U.S. based hydroentangled fabric producers are continuously improving their routes to those markets. Marketing, sales, customer service, fabric converting and warehousing facilities and people are being put in place and/or increased by some U.S. producers. European and Asian customers expect that U.S. producers will build cost effective production facilities in their regions as their needs grow.

* Marketing partnerships. Producers are looking for customers who have existing product lines and channels of distribution to markets where hydroentangled fabrics could have some applications. Most markets use a variety of products for specific needs. Fabric producers can't develop entire product lines and channels of distribution for a market that only wants one or two items based on that fabric, so hydroentangled fabric producers are becoming the suppliers of special products to round out the product line of producers and users of other fabric types, such as wovens, nonwovens, films and paper. Nonwovens companies often think of hydroentangled fabric producers as suppliers rather than competitors.

* Technology partnerships. Many of the most exciting possibilities for new applications and higher performance products are based on combining technologies. Combining the expertise and equipment of different companies can create genuinely new and unique fabrics. Many fabric technologies exist that have not been explored in combinations.

Some hydroentangled fabric producers have the capability to hydroentangle webs or fabrics formed by other companies' processes. This "toll" hydroentangling offers a completely new route to combining nonwovens technologies.

Suppliers of resins, finishing processes, physical treatments, chemical treatments, fibers and converting processes are bringing their technologies to the table as well.

The Nuances of Needlepunching

Needlepunching achieves direct fiber-to-fabric formation by subjecting a carded web to mechanical entanglement perpendicular to the orientation of the fiber in the web. This technology in its simplicity limits ways in which to produce highly engineered textiles. Where and how to diversify a product line in order to supply niche markets and still maintain a streamlined manufacturing process in a cost effective manner is the goal.

Needlefelting is a relatively fast, cost effective process that converts staple fiber into finished fabric. The basic method of manufacture involves mechanical interlocking of fibers in the web structure. The following steps are typical in needlepunch manufacture:

* Fiber Opening/Blending. One or more distinct staple fiber types are separated, if compact due to packaging of the raw material, and intimately blended. The fiber size ranges from 1.5-60 denier with a fiber length 40-115 mm.

* Carding. A lightweight web of the fibers is produced in the machine direction (zero degree) by disentangling and aligning the fibers.

* Crosslapping. Multiple layers of the carded web are stacked to achieve the desired weight and uniformity. Fiber orientation in the cross-wise direction (60-90 degrees) can be layered continuously.

* Needlepunching. As the crosslapped web enters the needling zone, thousands of barbed needles penetrate the web from one or both sides, consolidate it and give it the required three dimensional reinforcement.

A primary consideration is selection of a needle type to accommodate specific fiber properties and the desired fabric characteristics. Among the influences of needle structure are fiber type and size; needle configuration (length and gauge, blade shape, barb spacing, barb formation and barb kick-up); processing (efficiency, scope of effectiveness and structural damage to components); and maintenance (needle wear, replacement).

The amount of needling that occurs is a function of penetrations per square inch and how many of the available barbs penetrate the web. Typically, the range is between 250 and 10,000 total penetrations per square inch.

* Finishing. Post needling processes can include heat setting, flame singeing, calendering and the addition of chemical treatments and coatings.

Needlefelt weights range from 120-4000 grams sq. cm. Corresponding thickness can range from 1-50 mm. Fabric density can vary from 0.04-0.6 g/cc. Thickness and density modifications are obtainable by compressing the needlefelt under conditions of heat and pressure.

The Fiber Variables

Needlefelts can contain a combination of radically different fiber types in a single construction. Fibers can be blended or webs of single fiber types can be layered. A homogeneous fiber mix will enable the required fiber properties to translate effectively throughout the fabric. Asymmetrical layering of dissimilar webs is another way of achieving distinct fiber attributes. High modulus fibers are often incapable of withstanding the mechanical action of the carding process. These materials can be incorporated into the needled structure as a separate fabric.

Needlefelts can be supported or unsupported. The supported felt will contain a woven, knitted or nonwoven reinforcement fabric as an integral part of its structure. The inclusion of a support material improves the tensile properties of the finished fabric. The range of scrim materials is as unlimited as the fibers available combined with any textile method used to produce fabric.

By design, the reinforcement material addresses specific performance that isolates the individual contribution. Subjecting this then to a factor of translation efficiency, we can more closely predict performance. The requirements of needlefelts are essentially the additive qualities of the component materials and their interaction that determines effective performance.

The Malivlies Technology For Stitchbonding

The Malivlies technology involves the preparation of a web through a carding and crosslapping system. Fiber webs of up to 10 oz. sq. yard may be introduced to the Malivlies machine. The fiber length is generally greater than one inch. The web is presented to the knitting machine with all fiber oriented parallel to the knitting board. Great care must be taken in transferring the web from the crosslapper to the knitting machine so as not to elongate or distort the web.

Most knitting machines operate off-line from the crosslapping systems, as their respective production rates are disproportionate. For this reason, off-line take up and let off systems are provided to make the most efficient use of both machines. This is accomplished through the use of a carrier substrate of film that bears the strain of tension, insuring that the web remains intact through the path into the knitting bed.

The unique distinction of Malivlies fabric is that there is no yarn system stitched into the web. The fabric is formed by knitting the filaments of the web together, producing an aesthetically appealing fabric with excellent elongation in both the warp and weft directions. This permits good potential in applications where molding of the fabric is required.

One technology, the Maliwatt warp knitting technology, describes the introduction of a stitching yarn system into a base substrate for purposes of adding strength, aesthetic appeal or as a method of bonding various substrates.

Historically this technology has been applied to crosslapped web systems that have no strength or integrity in the warp or weft direction. By applying one or two yarn systems into the web, considerable strength and stability result, as well as a surface texture that may be suitable for printing.

The yarn systems may be applied at a density of from less than one yarn up to 22 yarn ends per wide inch. The yarn applied by the knitting bars may range broadly from 40 denier polyester up to 500 denier.

Maliwatt machines are in production in the U.S. using "Lycra," polyester and fiberglass and have demonstrated successful operation on "Kevlar," graphite and polypropylene based filaments on extended research and development programs. Most of these types of machines are under production making mattress covers, interlinings and wiping cloths.

The ability of the Maliwatt machinery to bond substrates together with a yarn system is legendary. Knits and webs can be bonded together to form a quilted type structure. This might be a bedspread with an attractive and durable surface cover and a lofty web interior. The same structure could be applied to a machine washable diaper or as an insulator for heat or cold.

Another form of bonding involves the fabrication of a hook/loop structure. Since loops can be readily assembled onto a woven/nonwoven substrate, various applications have been uncovered that apply to the "velcro" principle. Significant among these involves the attachment of automotive upholstery to the fame of the seat.

The set-up of the warp knitting machine to run a Malimo configuration is similar to Maliwatt with the exception of adding a weft yarn into the fabric. Yarns, webs, nonwovens, film, rovings, knits or woven fabrics may be introduced into the Malimo. One or more of these components may be introduced at the same time.

An appendage has also been added to the basic Malimo machine that greatly varies its performance capability. Historically, lateral movement of warp yarns were governed by pattern wheels that have two limitations: first, the repeat pattern was short and, second, the lateral movement was greatly limited.

A new electronic patterning device allows for a pattern to repeat up to every 14 linear meters. The electronic aspects of this capability allow for the required pattern to be sketched with a drafting apparatus on a color based CRT. The drawing is then converted by software into both the mechanical parameters to set up the warp yarns onto the machine as well as the electronic commands necessary to drive the motors that control the warp yarns.

Although the aesthetic possibilities are obvious for this device, it was designed with the industrial fabric in mind. The premise is that warp yarns might be stitched onto a base fabric or nonwoven for handling and stability purposes yet controlled laterally with such movement as to conform to the actual end product.

Compressive Treatment Technology

The mechanical post-treatment of nonwovens is a cost effective solution to enhancing the performance of a material without the need to re-engineer the basic web/fabric structure. There are many finishing machines available today that can alter materials in such a manner that they will have increased fields of application, thus increasing market opportunities for converted products.

Surface treatment by mechanical methods can increase bulk, softness, absorbency, drape, aesthetic appeal, stretch and conformability. These terms describe physical changes that can be obtained through the use and application of compressive treatment technology. Compacting, compressive shrinkage, stuffer boxes, creping and calendering devices are all mechanical methods that produce alterations in web structure.

The product is changed by the introduction of shear forces on the material. Also, the introduction of a pure crushing load, such as calendering, will permanently alter the characteristics of a material. Compressive treatment occurs when a material is overfed, under pressure, into a converging passage or nip, then into a diverging cavity with sufficient vertical and longitudinal space for a columnar collapse to occur.

Typical mechanical compressive treatment machinery consists of one or two feed rolls working in harmony with the compacting zone. The substrate is presented to the compaction section or cavity by the feed roll or rolls. The precise geometry of the nip formed in the engagement of the roll/rolls, shoe/shoes and/or retarding medium create the proper cavity necessary to impart compaction to a range of web structures.

Obviously, the rate of feed into the treatment zone and the rate of speed that the material leaves the treatment zone controls the amount of residual compaction. The relative permanence of this compaction is dependent on the specific fiber content of a web. The introduction of heat to the drive roll/rolls and transference of the heat to the web during mechanical treatment can impart semi-permanent to permanent results in the processed web. The thermoplastic fibers and binding systems will become elastic or plastic during processing and a controlled lengthwise compression will take place. The compressive treatment process can be especially effective on nonwoven webs because of their frequent composite makeups.

Precisely controlling the size, shape and temperature of the treatment zone is the critical ingredient to the successful application of compressive treatment technology. This is also true of devices that achieve compaction by stretching a web between an elastomeric blanket and a heated roll. The pressure roll squeezes the elastomeric blanket against the shrinking drum, which lengthens the blanket. When the clearance increases and the squeeze pressure decreases, the blanket is allowed to return to its original thickness and length, resulting in a fabric compaction between the elastomeric blanket and the shrinking drum.

Whatever method is used, the rearrangement of the web structure through the use and application of mechanical post treatment processes can create new market opportunities for converted nonwoven products without re-engineering existing materials.

The Enhancement Characteristics

For example, the following is a list of nonwoven enhancement characteristics that are achieved by the compressive treatment process:

* A change in physical appearance of the substrate sometimes referred to as "surface texture" is a visual effect of pattern creping or compacting of a web structure that can separate and distinguish a product from the competition.

* Increased bulk is a measurable rise in thickness of a treated product and also a rise in basis weight per unit area. In specific web structures, this can translate into improved absorption in which both rate and volume of liquid pick up and retention are increased.

* Improved drape, flexibility, softness and conformability are obvious attributes of fabrics designed to be used in various apparel applications. Also, these web qualities are advantageous in other near-to-skin end uses such as bandages and medical disposables. The obvious functional goal here is to make a nonwoven that exhibits as many textile-like attributes as possible.

* Cover enhancement, opacity, light reflection, density change and porosity are additional by-products of linear compaction. These characteristics applied to certain substrates produce unlimited opportunities for engineered products such as nonwovens for filtration.

* Stretch and recovery, energy absorption and resistance to tear features are extremely useful in various packaging applications.

Insofar as the market seems to be leading the industry towards increasingly more sophisticated nonwoven fabrics, the solution may be as simple as ameliorating an existing product through the application of compressive treatment technology. Now, more than ever before, a team effort is needed between fabric and machinery manufacturers to understand the needs of customers.

Recent innovations in compressive treatment technology have greatly expanded the product types that can be processed by compaction devices. When listening to customer requirements, think of converting a product through mechanical post-treatment before going back to the drawing board to re-engineer a product for a new application.

A simple converting operation may open up a myriad of options and possibilities for a basic product. The application of compressive treatment technology can not only enhance a company's product, but also a company's profit.
COPYRIGHT 1991 Rodman Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Manns, John; Weninger, Stephen; Searle, Sheldon; Harris, Jane; Heydt, Rick; Goodchild, William
Publication:Nonwovens Industry
Date:Oct 1, 1991
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