What is a Nonwoven?
A Nonwoven is an engineered fabric structure made directly from fibres or from the materials that the fibres themselves are made. The term “nonwoven” is often used as a generic description of a fabric that has been produced by a process different from weaving or, more broadly, a fabric that is different from a traditional textile fabric, paper sheet, or plastic film. Like textile fabrics, paper sheets, and plastic films, a nonwoven is a planar structure that can be produced with varying degrees of integrity, surface texture, thickness, flexibility, and porosity. Each of these items of commerce is manufactured by a distinct industry and each is often associated with different, but very basic applications. Specific associations include textile fabrics with clothing and home furnishings, paper sheets with writing and printing, and plastic films with wrapping and packaging. These apparently different commercial items are similar in the sense that each is a fibre-based material, and that many application properties often considered to be unique to textiles, paper, or plastic materials can be met or exceeded by some form of nonwoven fabric. In fact, the technologies used to make nonwoven fabrics are based on the fundamental principles used to produce textiles, papers, and plastics. In this regard, nonwovens are fabrics that are made by (a) mechanically, chemically, or thermally interlocking layers or networks of fibres or filaments or yarns, (b) interlocking fibres or filaments concurrent with their extrusion, (c) perforating films, or (d) forming porous films concurrent with their extrusion.

A number of definitions have been drafted to help in distinguishing nonwovens from other fabrics. The Textile Institute defines nonwovens, in general, as

...textile structures made directly from fibre rather than yarn. Fabrics are normally made from continuous filaments or from fibre webs or batts strengthened by bonding using various techniques: these include adhesive bonding, mechanical interlocking by needling or fluid jet entanglement, thermal bonding and stitch bonding.

The American Society for Testing and Materials (ASTM D 1117-80) defines a nonwoven fabric as:

A textile structure produced by bonding or interlocking of fibres, or both, accomplished by mechanical, chemical, or solvent means and combinations thereof.

The International Standards Organization (ISO 9092:1988) gives the following definition: A manufactured sheet, web, or batt of directionally or randomly oriented fibres, bonded by friction, and/or cohesion and/or adhesion, excluding paper (see Note 1) and products which are woven, knitted, tufted, or stitchbonded incorporating binding yarns or filaments, or felted by wet-milling, whether or not additionally needled (see Note 2). The fibres may be of natural or man-made origin. They may be staple or continuous filaments or be formed in situ (see Note 3).

Note 1: To distinguish wet-laid nonwovens from wet-laid papers, a material shall be regarded as a nonwoven if (a) more than 50 percent by mass of its fibrous content is made up of fibres (excluding chemically digested vegetable fibres) with a length to diameter ratio greater than 300; or, if the conditions in (a) do not apply, then (b) if the following conditions are fulfilled: (i) more than 30 percent by mass of its fibrous content is made up of fibres (excluding chemically digested vegetable fibres) with a length to diameter ratio greater than 300 and (ii) its density is less than 0.40 g/cm3.

Note 2: The commonly used term needlefelt has given rise to some confusion since it restrictively associates needling with felting or felt-like products. In fact, needling (mechanical interlocking of fibres by specially designed needles or barbs) is a major bonding method of nonwovens in its own right and is frequently the only consolidation route for nonwovens ranging from medical/hygienic disposables to spunlaid geotextiles.

Note 3: The appearance of a relatively new group of products such as splitfilms, extruded meshes and nets, etc., presents a further borderline case between nonwovens and related technologies (in this case, plastics). For the purpose of this International Standard, products shall be regarded as nonwovens if they meet the requirements of the core definition above and where their main structural element can be regarded as fibrous, however derived....
The INDA Association of the Nonwoven Fabrics Industry definition of nonwovens is: A sheet, web, or batt of natural and/or man-made fibres or filaments, excluding paper, that have not been converted into yarns, and that are bonded to each other by any of several means.


1. To distinguish nonwovens from papers, a material shall be defined as a nonwoven if:
(A) More than 50 percent by mass of its fibrous content is made up of fibres (excluding chemically digested vegetable fibres) with a length to diameter ratio greater than 300;
(B) More than 50 percent by mass of its fibrous content is made up of fibres as in "A" above and meeting one or both of the following criteria:
1. Length-to-diameter ratio greater than 600.
2. The density of the fabric is less than 0.4 g/cm3
3. Bonding method may include any of the following means or any combination thereof, including but not limited to:
A. Adding an adhesive.
B. Thermally fusing the fibres or filaments to each other or to other meltable fibres or powders.
C. Fusing fibres by first dissolving then resolidifying their surfaces.
D. Creating physical tangles or tufts among the fibres.
E. Stitching the fibres or filaments in place.
4. A nonwoven may be a structural component of a composite.
5. Nonwoven structures may incorporate monofilaments or yarns.
As items of commerce, nonwovens are recognized internationally by government agencies, trade associations, and business enterprises. In the US, statistical data on establishments engaged in manufacturing nonwoven fabrics are reported under Standard Industrial Classification 2297. Nonwoven fabrics are produced in weights ranging from less than 10 g/m2 (0.3 oz/yd2) to as much as 3500 g/m2 (100 oz/yd2) and are sold in the form of rolls cut to lengths and widths to accommodate specific application requirements.

As engineered structures, nonwovens can be designed to have appearances, textures, and other aesthetic properties comparable to traditional wovens and knits. In terms of performance and functional properties, nonwovens can be constructed to be equivalent or superior to traditional papers or films. Nonwovens are, indeed, a distinct class of fibre-based materials and have the characteristics of many different fabric types and properties appropriate for many traditional emerging applications.
Historical Background

Nonwovens are often viewed as the “new kid” in the world of fabric manufacturing.
However, a number of accounts regard nonwovens as a fabric of antiquity; thus, a short history. A contemporary article describes a method used since the eighth century BC to make the felt used in nomadic dwellings. The technique consists of placing loose wool on an old dampened felt; soaking the fibres with water; layering the old felt, new wool, and a skin from a freshly killed yak around a pole which serves as an axle; and dragging the bundle by horseback around in circles for several hours. An earlier paper on nonwoven felts, notes that the Mongolian tribes of Asia were early nonwoven fabric users, and that reference to felt materials is contained in the writings of the ancient Greeks and Romans. The felt-making process has also been associated with the travels of a Benedictine monk on an eighth-century pilgrimage from Caen to the shrine at Mont-Saint-Michel. During the journey, the monk placed some greased wool, plucked from a wandering sheep, in his sandals to relieve his tired, painful feet. At the end of the day, he examined the wool and noted that the fibres had interlocked into a matted fabric due to the working action of his feet against the sandal and the presence of heat and moisture. The discovery is said to mark the birth of felt-making in the Western world, and resulted in the monk Fuetre (St. Clement) being named the patron saint of the felt industry.
A noted Japanese scientist, Inagaki traces the production and use of paper made from long (15-17 mm) fibres to a passage from Choya Gunsai, a type of paper that was used to make clothes between 983 BC and 4 AD. The method is still used today to make the traditional kamiko, or paper robe. The combination of long fibre and an external binder appears to be the key factor in producing a durable fabric. Inagaki notes that the fabric is made as follows: "Pure kozo is dissolved raw in water and sieved to produce sheets of longfibreed paper. The sheets are put together using konjak mannan glue, and the resulting cloth is reinforced by applications of persimmon tannin. The cloth is crumpled so that it may develop suppleness. The process is repeated several times until the cloth becomes sturdy yet soft enough to be made into robes."
A prominent Chinese scholar, Yang notes an anomaly from the ancient practice of sericulture. When silk worms are ready to spin their cocoons and fall from their spinning trellis onto a flat surface, they secrete filaments in the form of a "flat cocoon." Records from the Song Dynasty (960-1279) describe neck tie and quilt cover fabrics up to 1.23 meters wide and 7.68 meters long made directly from filaments. Qing Dynasty (1644-1911) articles provide statements to the effect that these quilt covers were made by "...ten thousand worms making a common cocoon," with instructions not to place silk worms on a trellis when they are ready to spin their cocoons, but to let them stay on a flat surface, because "...they cannot produce cocoons, but will discharge silk filaments on the flat surface, yielding a bright web fabric."
Producing nonwoven fabrics in an industrial setting has a more recent but equally interesting history that appears to follow a recurring theme, namely, finding a way to make better fabric materials more efficiently. Finding a better way to make gauze resulted in Johnson & Johnson's involvement in nonwovens in the 1930s. Robert Johnson attributes his company's venture into nonwovens to a discussion regarding the under-utilization of sophisticated spinning and weaving machinery to make surgical gauze, that for the most part is ..."used once, for a short time, and then thrown away." Response to the question, "Can't we work out a simpler method?" yielded a simple statement of the problem, namely, to ... "take cotton or other fibres and spread them into a sheet, ... give the sheet some kind of treatment that would bond the fibres together and so form a non-woven fabric". The proposed method ... "would save a great deal of time and effort" and ..."eliminate the process of spinning the fibres into threads, as well as that of weaving the threads into gauze."

After ten years of experimentation, the nonwovens department and its Masslinn fabrics became a division of the Chicopee Manufacturing Corporation. Rayon replaced cotton in most commercial products, and the fabrics were put to use in bed pads, dental napkins, surgical towels, disposable diapers, sanitary napkins, hand towels, casket linings, pattern markers, ribbons, and wiping cloths. Nearly forty years later, production facilities using jets of water to bond fibres together to produce nonwoven surgical gauze were completed. Today, many woven gauze applications have been replaced by nonwoven fabrics.
Freudenberg of Germany also entered the nonwovens area in the 1930s. Freudenberg‘s quest was to find a substitute for leather. Today this firm is a major worldwide producer of nonwoven interlinings a( woven fabric replacement). Other industrial pioneers involved in developing nonwovens as textile replacements include Avondale, Kimberly-Clark, Kendall, and West Point.

The concept of producing special papers from long fibres by a single continuous process has been attributed to Fay H. Osborne. Osborne's analysis of the properties of soft, strong, flexible cigar tissue wrap and durable stencil paper "hand made" in Japan initiated an eight-year study focused on locating appropriate sources of fibre and developing a method to modify the modern papermaking process to accommodate these fibres. Osborne observed that the cylindrical, rigid fibres in the Japanese hand papers were sixty times longer, four times thinner, and extensively more uniform than fibres used in normal paper. After evaluating scores of natural fibres and many of the new man-made fibres, he determined that musa textilis, or manila hemp, grown in the Philippines and used for making rope, would meet his technical requirements.

Processing these long fibres at normal water-fibre dilution ratios on conventional papermaking machinery, however, would not work. Osborne's solution to the problem was to change slurry consistency from 0.25 to 0.0025 percent fibre, and to incline the forming wire to an angle of about 20 percent. The first commercial long-fibre paper was produced at Dexter in 1934; six years later, product diversity included specialty papers for electrolytic condensers, vacuum bags, stencils, meat casings, tea bags, and diapers. Later developments include wet -laid nonwovens made from various synthetic, glass, and natural fibre furnishes.

Considering the success demonstrated by textile and paper producers in making fabrics directly from fibres, it would appear that a logical next step would be to make fabrics directly from the materials used to make the fibres themselves — cutting out altogether the fibre production step. It is not surprising, therefore, that following the successful introduction of synthetic fibres into traditional woven and knitted fabrics, fibre producers devoted some focus on nonwovens. The quest by synthetic fibre producers for new applications and markets resulted in the introduction of synthetic staple into nonwoven products in the mid-1950s.

The knowledge gained in adapting these new fibres to the various commercial nonwoven processes available at the time resulted in an increased understanding of how these processes really work. These discoveries, in turn, brought about improvements to those processes and expanded into the development of new technologies for making fabrics directly from fibres, and expanded them further into the development of methods for making fabric directly from the fibre-forming polymer itself. Two closely related technologies are illustrative of methods for making fabric directly from the fibre-forming polymers, namely, spunbonding and meltblowing.

The spunbond process transforms polymer directly to fabric by extruding filaments, orienting them as bundles or groupings, layering them on a conveying screen in a patterned array, and interlocking them by thermal fusion, mechanical entanglement, chemical adhesives, or combinations of the above. The first three operations are elements of synthetic fibre extrusion, also known as spinning, and constitute the spun or web formation phase of the process, while the last operation is the web-consolidation or bonding phase — hence the generic term spun-bond. Several methods of achieving the spunbond process have been developed as commercial operations, and each produces fabric with a high ratio of strength per unit weight. Technology for commercially producing spunbonds was developed over forty years ago in Germany by Freudenberg and in the United States by DuPont. These early systems, as well as others developed later in the Netherlands, England, and France were guarded proprietary processes. A spunbond technology system developed by Lurgi in Germany was sold on a licensing basis during the early 1970s. The various technologies differ in the methods of passing the polymer through the spinneret, separating the filaments at the extruder head, orienting the filaments, collecting the filaments on the conveyor screen, and/or bonding the filaments together.

Meltblown fabrics, like most spunbonds, are manufactured directly from thermoplastic resins. The resin in chip form is heated, hence the term melt, to the liquid state and, as it passes through an extrusion orifice, is injected (blown) with sonic-velocity air at about 250-500° C. The fast-moving air streams effectively shatter, stretch, and solidify the molten polymer into an attenuated, very fine-diameter fibrous array. The array is then separated from the air stream as a randomly entangled web and compressed between heated rolls. The combination of fine-diameters, random entanglement, and close packing brings about a fabric structure with a high surface area and a large number of pores per unit weight. Meltblown technology was developed at the US Naval Research Laboratories. A description of the original work in this field was published by Wente in 1956. Researchers at Esso and others independently at 3M improved the process during the mid-1960s and commercialized products in the late 1960s. In the early 1970s, Exxon began a worldwide licensing program, which attracted firms such as Kimberly-Clark, Riegel Paper, Pall, and Electrolux. Over the past two decades, developments in melt-blown technology have focused on improvements in die design, web handling, resin requirements, energy utilization, and other means to enhance productivity and fabric strength.

Nonwoven fabric development during the 1980s and into the new millennium expanded on the general theme of finding a way to make better fabric materials more efficiently through the process of technology hybridization. Nonwoven hybrid technologies include
(1) methods to combine two or more nonwoven fabrics made by any of the primary nonwoven manufacturing systems,
(2) methods to provide a combination of fabric properties, and
(3) methods to produce true composite nonwoven structures. Combining systems employ lamination technology, or at least one basic nonwoven web formation or consolidation method, to join two or more fabric layers. Combination systems utilize at least one basic nonwoven web formation, bonding, or finishing element to enhance the properties of one or more fabric substrates. Composite systems integrate two or more nonwoven web formation technologies to produce nonwoven structures.

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