Nonwoven fabric is a fabric

Fabric

A fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...

-like material made from long fibres, bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry

Textile industry

The textile industry is primarily concerned with the production of yarn, and cloth and the subsequent design or manufacture of clothing and their distribution. The raw material may be natural, or synthetic using products of the chemical industry....

 to denote fabrics, such as felt

Felt

Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....

, which are neither woven

Weaving

Weaving is a method of fabric production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. The other methods are knitting, lace making and felting. The longitudinal threads are called the warp and the lateral threads are the weft or filling...

 nor knitted

Knitting

Knitting is a method by which thread or yarn may be turned into cloth or other fine crafts. Knitted fabric consists of consecutive rows of loops, called stitches. As each row progresses, a new loop is pulled through an existing loop. The active stitches are held on a needle until another loop can...

. Nonwoven materials typically lack strength unless densified or reinforced by a backing. In recent years, nonwovens have become an alternative to polyurethane

Polyurethane

A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 foam.

Applications

Nonwoven fabrics are broadly defined as sheet or web structures bonded together by entangling fibre or filaments (and by perforating films) mechanically, thermally or chemically. They are flat, porous sheets that are made directly from separate fibres or from molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibres to yarn. Typically, a certain percentage of recycled fabrics and oil-based materials are used in nonwoven fabrics. The percentage of recycled fabrics vary based upon the strength of material needed for the specific use. Conversely, some nonwoven fabrics can be recycled after use, given the proper treatment and facilities. For this reason, some consider nonwovens a more ecological fabric for certain applications, especially in fields and industries where disposable or single use products are important, such as hospitals, schools, nursing homes and luxury accommodations.

Nonwoven fabrics are engineered fabrics that may be a limited life, single-use fabric or a very durable fabric. Nonwoven fabrics provide specific functions such as absorbency, liquid repellence, resilience, stretch, softness, strength, flame retardancy, washability, cushioning, filtering, use as a bacterial barrier and sterility. These properties are often combined to create fabrics suited for specific jobs, while achieving a good balance between product use-life and cost. They can mimic the appearance, texture and strength of a woven fabric and can be as bulky as the thickest paddings. In combination with other materials they provide a spectrum of products with diverse properties, and are used alone or as components of apparel, home furnishings, health care, engineering, industrial and consumer goods.

Non-woven materials are used in numerous applications, including:

Hygiene

• baby diaper
  Diaper
  A nappy or a diaper is a kind of pant that allows one to defecate or urinate on oneself discreetly. When diapers become soiled, they require changing; this process is often performed by a second person such as a parent or caregiver...
  
  s or nappies
• feminine hygiene
  Feminine hygiene
  Feminine hygiene is a general euphemism used to describe personal care products used by women during menstruation, vaginal discharge, and other bodily functions related to the vulva...
  
  
• adult incontinence
  Urinary incontinence
  Urinary incontinence is any involuntary leakage of urine. It is a common and distressing problem, which may have a profound impact on quality of life. Urinary incontinence almost always results from an underlying treatable medical condition but is under-reported to medical practitioners...
  
   products
• wet wipes
• bandages and wound dressings
• disposable bath and face towels
• disposable slippers and footwear

Medical

• isolation gowns
• surgical gowns
• surgical drapes and covers
• surgical scrub suits
• caps
• medical packaging: porosity allows gas sterilization

Filters

• gasoline, oil and air - including HEPA
  HEPA
  High-Efficiency Particulate Air or HEPA is a type of air filter. Filters that are awarded the HEPA accolade are used in various locations, whether in medical facilities, automotive vehicles, airplanes, home filters, or wherever very pure air is sought. The filter must satisfy certain standards of...
  
   filtration
• water, coffee, tea bags
• pharmceutical industry
• mineral processing
• liquid cartridge and bag filters
• vacuum bags
• allergen membranes or laminates with non woven layers

Geotextiles

• soil stabilizers and roadway underlayment
• foundation stabilizers
• erosion control
• canals construction
• drainage systems
• geomembrane protection
• frost protection
• agriculture mulch
• pond and canal water barriers
• sand infiltration barrier for drainage tile

Other

• carpet
  Carpet
  A carpet is a textile floor covering consisting of an upper layer of "pile" attached to a backing. The pile is generally either made from wool or a manmade fibre such as polypropylene,nylon or polyester and usually consists of twisted tufts which are often heat-treated to maintain their...
  
   backing, primary and secondary
• composites
  Composite material
  Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
  
  
  • marine sail laminates
  • tablecover laminates
  • chopped strand mat
• backing/stabilizer for machine embroidery
  Machine embroidery
  Machine embroidery is an embroidery process whereby a sewing machine or embroidery machine is used to create patterns on textiles. It is used commercially in product branding, corporate advertising, and uniform adornment. Hobbyists also machine embroider for personal sewing and craft projects.There...
  
  
• packaging  where porosity is needed
• insulation
  Thermal insulation
  Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...
  
   (fiberglass
  Fiberglass
  Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
  
   batting
  Batting (material)
  Batting is a layer of insulation used in quilting between a top layer of patchwork and a bottom layer of backing material. Batting is usually made of cotton, polyester, and/or wool....
  
  )
• pillows, cushions, and upholstery
  Upholstery
  Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word upholstery comes from the Middle English word upholder, which referred to a tradesman who held up his goods. The term is equally applicable to domestic,...
  
   padding
• batting
  Batting (material)
  Batting is a layer of insulation used in quilting between a top layer of patchwork and a bottom layer of backing material. Batting is usually made of cotton, polyester, and/or wool....
  
   in quilts or comforters
• consumer and medical face masks
• mailing envelope
  Envelope
  An envelope is a common packaging item, usually made of thin flat material. It is designed to contain a flat object, such as a letter or card....
  
  s
• tarps, tenting and transportation (lumber, steel) wrapping
• disposable clothing (foot coverings, coveralls)

Manufacturing processes

Nonwovens are typically manufactured by putting small fibres together in the form of a sheet or web (similar to paper

Paper

Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 on a paper machine), and then binding them either mechanically (as in the case of felt, by interlocking them with serrated needles such that the inter-fibre friction results in a stronger fabric), with an adhesive

Adhesive

An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

, or thermally (by applying binder

Binder

The reaper-binder, or binder, was a farm implement that improved upon the reaper. The binder was invented in 1872 by Charles Withington. In addition to cutting the small-grain crop, it would also tie the stems into small bundles, or sheaves...

 (in the form of powder, paste, or polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 melt) and melting the binder onto the web by increasing temperature).

Staple nonwovens

Staple nonwovens are made in 2 steps. Fibres are first spun, cut to a few centimetres length, and put into bale

Bale

- Places :* Bale , a small town in Croatia* Bale, California, in Napa County* Bale, Norfolk in England* Bale, Poland* Balé Province, Burkina Faso* Basel, the Swiss city, for which the French name is Bâle-Ethiopia:* Bale Mountains...

s. These bales are then dispersed on a conveyor belt

Conveyor belt

A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley...

, and the fibres are spread in a uniform web by a wetlaid process or by carding

Carding

Carding is a mechanical process that breaks up locks and unorganised clumps of fibre and then aligns the individual fibres so that they are more or less parallel with each other. The word is derived from the Latin carduus meaning teasel, as dried vegetable teasels were first used to comb the raw wool...

. Wetlaid operations typically use 1/4" to 3/4" long fibres, but sometimes longer if the fibre is stiff or thick. Carding operations typically use ~1.5" long fibres. Rayon

Rayon

Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber. Rayon is known by the names viscose rayon and art silk in the textile industry...

 used to be a common fibre in nonwovens, now greatly replaced by PET and PP. Fibreglass is wetlaid into mats for use in roofing and shingles. Synthetic fibre blends are wetlaid along with cellulose

Cellulose

Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 for single-use fabrics. Staple nonwovens are bonded by using either resin or thermally. Bonding can be throughout the web by resin saturation or overall thermal bonding or in a distinct pattern via resin printing or thermal spot bonding. Conforming with staple fibres usually refers to a combination with meltblown, often used in high-end textile insulations.
Melt Blown non wovens are produced by extruding melted polymer fibres through a spin net or die consisting of up to 40 holes per inch to form long thin fibres which are stretched and cooled by passing hot air over the fibres as they fall from the die.The resultant web is collected into rolls and subsequently converted to finished products.The extremely fine fibres typically polypropylene differ from other extrusions particularly spun bond in that they have low intrinsic strength but much smaller size offering key properties.Often melt blown is added to spun bond to form SM or SMS webs, which are strong and offer the intrinsic benefits of fine fibres such as fine filtration, low pressure drop as used in face masks or filters and physical benefits such as acoustic insulation as used in dishwashers. One of the largest users of SM and SMS materials is the disposable diaper and feminine care industry

Spunlaid nonwovens

Spunlaid nonwovens are made in one continuous process. Fibres are spun and then directly dispersed into a web by deflectors or can be directed with air streams. This technique leads to faster belt speeds, and cheaper costs. Several variants of this concept are available, but the leading technology is the REICOFIL machinery. PP spunbonds run faster and at lower temperatures than PET spunbonds, mostly due to the difference in melting points. Spunbond has been combined with meltblown nonwovens, conforming them into a layered product called SMS (spun-melt-spun). Meltblown nonwovens have extremely fine fibre diameters but are not strong fabrics. SMS fabrics, made completely from PP are water-repellent and fine enough to serve as disposable fabrics. Meltblown is often used as filter media, being able to capture very fine particles. Spunlaid is bonded by either resin or thermally. Regarding the bonding of Spunlaid, Rieter has launched a new generation of nonwovens called Spunjet. In fact, Spunjet is the bonding of the Spunlaid filaments thanks to the hydroentanglement

Air-laid paper

Air-laid paper

Paper

Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 is a textile-like material categorized as a nonwoven fabric made from wood pulp

Wood pulp

Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or waste paper. Wood pulp is the most common raw material in papermaking.-History:...

. Unlike the normal papermaking process, air-laid paper does not use water as the carrying medium for the fibre. Fibres are carried and formed to the structure of paper by air.

Other

Nonwovens can also start with films and fibrillate, serrate or vacuum-form them with patterned holes. Fiberglass nonwovens are of two basic types. Wet laid mat or "glass tissue" use wet-chopped, heavy denier fibers in the 6 to 20 micrometre diameter range. Flame attenuated mats or "batts" use discontinuous fine denier fibres in the 0.1 to 6 range. The latter is similar, though run at much higher temperatures, to meltblown thermoplastic nonwovens. Wet laid mat is almost always wet resin bonded with a curtain coater, while batts are usually spray bonded with wet or dry resin. An unusual process produces polyethylene fibrils in a Freon-like fluid, forming them into a paper-like product and then calendering them to create Tyvek

Tyvek

Tyvek is a brand of flashspun high-density polyethylene fibers, a synthetic material; the name is a registered trademark of DuPont. The material is very strong; it is difficult to tear but can easily be cut with scissors or a knife...

.

Bonding

Both staple and spunlaid nonwovens would have no mechanical resistance in and of themselves, without the bonding step. Several methods can be used:

• thermal bonding
  • Use of a heat sealer
    Heat sealer
    A heat sealer is a machine used to seal products, packaging, and other thermoplastic materials using heat. This can be with uniform thermoplastic monolayers or with materials having several layers, at least one being thermoplastic...
    
    
  • using a large oven for curing
    Curing (chemistry)
    Curing is a term in polymer chemistry and process engineering that refers to the toughening or hardening of a polymer material by cross-linking of polymer chains, brought about by chemical additives, ultraviolet radiation, electron beam or heat...
    
    
  • calendering
    Calendering
    Calendering is a finishing process used on cloth where fabric is folded in half and passed under rollers at high temperatures and pressures. Calendering is used on fabrics such as moire to produce its watered effect and also on cambric and some types of sateens.In preparation for calendering, the...
    
     through heated rollers (called spunbond when combined with spunlaid webs), calenders can be smooth faced for an overall bond or patterned for a softer, more tear resistant bond
• hydro-entanglement: mechanical intertwining of fibers by water jets (called spunlace)
• ultrasonic pattern bonding: used in high-loft or fabric insulation/quilts/bedding
• needlepunching/needlefelting: mechanical intertwining of fibres by needles
• chemical bonding (wetlaid process): use of binders (such as latex emulsion or solution polymers) to chemically join the fibers. A more expensive route uses binder fibres or powders that soften and melt to hold other non-melting fibres together
  • one type of cotton staple nonwoven is treated with sodium hydroxide to shrink bond the mat, the caustic causes the cellulose-based fibres to curl and shrink around one another as the bonding technique
  • one unusual polyamide(Cerex) is self-bonded with gas-phase acid
• meltblown: fibre is bonded as air attenuated fibers intertangle with themselves during simultaneous fiber and web formation.

External links

• http://www.edana.org association of nonwovens
• http://www.inda.org The Association of the Nonwovens Fabrics Industry
• / http://www.rupainks.com An ISO 9001-2008 certified printing ink manufacturer
• / http://www.screenink.in An ISO 9001-2008 certified Nonwovens printing ink manufacturer

See also

• Disposable towel
  Disposable towel
  Disposable towels are a relatively new invention, made from nonwoven fibres. They were first popularised by the hospital supply industry, but now relatively common in resorts, hotels, beauty salons, day cares and similar fields. Their main advantage is the hygiene and cleanliness that they...
  
  
• / http://www.silkscreenink.in An ISO 9001-2008 certified Nonwovens printing ink manufacturer