Glossary of Nonwoven Terms
For more extensive definitions and information, please see the INDA and EDANA glossaries, located at the end of this page.
What It Is
The process by which a gas or liquid is taken up within a material. An absorbent nonwoven holds the gas or liquid within the fibers themselves.
What It Is
The process by which a gas or liquid is taken up by the surface of a material. An adsorbent nonwoven wicks and holds the gas or liquid between the fibers.
A web, nonwoven or other material that supports and reinforces the back of a product such as carpeting or wallpaper. Backings provide dimensional stability and enhance the performance of the face fabric.
An adhesive type substance applied to the back side of a fabric for the purpose of locking pile yarn into a carpet backing, or bonding a secondary backing to the primary backing, increasing fabric body or stiffness, or imparting flame retardancy to the fabric.
A compressed and bound package of fibers – a common shipping package for fibers.
A number or an amount of items forming a group i.e. a batch (amount) of fibers.
BASIS WEIGHT (MASS PER UNIT AREA)
The mass of a unit area of fabric. Examples: grams per square meter – ounces per square yard. Basis Weight is mass per square area and is not the same a DENSITY, which is mass per cubic volume.
A soft bulky assembly of fibers, usually carded. A carded web is sometimes referred to as a batt.
Fibers consisting of two polymeric compounds arranged in a core-sheath (concentric or eccentric) or a side by side or a matrix or ‘islands in the sea’ configuration, chosen to ensure one component softens at a sufficiently lower temperature than the other in order to maintain the structural integrity or to create specific characteristics.
An adhesive substance, generally a high polymer in a solid form (powder, film, fiber) or as a foam, or in a liquid form (emulsion, dispersion, solution) used for bonding the constituent elements of a web or enhancing their adhesion, in order to provide the nonwoven fabric cohesion, integrity and/or strength and additional properties.
Generally, thermoplastic fibers used as thermal bonding fibers in conjunction with other fibers with a higher softening point or non-melting fibers.
Some binder fibers that may not be thermoplastic can be activated by solvent (e.g. water).
The ability of a substance to be broken down by bacteria so that it can be consumed by the environment.
A combination of two or more fiber types in making fabrics.
Conversion of a fibrous web into a nonwoven by chemical (adhesive/solvent) means or by physical (mechanical or thermal) means. The bonding may be distributed all over (through or area bonding) or restricted to predetermined, discrete sites (point or print bonding).
See AIR PERMEABILITY.
A machine used to bond fibers of a web or sheets of fabric or film to each other or to create surface features on these sheets. It consists of two or more heavy cylinders that impart heat and pressure to the sheets that are drawn between them. The rollers can be mirror smooth, embossed with a pattern, or porous.
A process for thermally bonding webs by passing them through the nip of a pair of rolls, one or both of which are heated. Plain or patterned rolls may be employed (see POINT BONDING). Alternatively, a blanket calendar may be used.
A mechanical finishing process used to laminate or to produce special surface features such as high luster, glazing and embossed patterns.
A machine designed to separate fibers and remove impurities; align and deliver them to be laid down as a web or to be further separated and fed to an airlaid process. The fibers in the web are aligned with each other predominantly in the same direction.
The machine consists of a series of rolls or a drum that are covered with many projecting wires or metal teeth. These wire-clothed rolls or drums are called cards.
A process for making fibrous webs in which the fibers are aligned essentially parallel to each other in the direction in which the machine produces the web (machine direction).
A carded web, bonded by one or more techniques to provide fabric integrity.
A disposable filter media which is generally long and cylindrical which is placed in a sealed filtration receptacle. The contaminated fluid flows from the outer edge of the filter to the inner hollow core on exiting but leaves its particles in the cartridge media.
Made from plants that produce fibrous products based on polymers of the cellulose molecule. Cotton plants produce separate cellulose fibers, whereas wood pulp is made by mechanically and/or chemically separating wood fibers. Other sources of cellulose are fibers such as flax manila, ramie and jute.
Rayon is made by dissolving wood pulp in a solution and extruding that solution through spinnerets into a chemical bath that regenerates the fibers.
Cubic Feet per Minute. Technically, Cubic Feet per Minute per Square Foot. Unit of measure for quantifying airflow through a filter media.
A method of bonding webs of fibers by chemical agents that may include adhesives and solvents. The process may entail one or more of the following methods: impregnation, spraying, printing and foam application.
NOTE: chemical bonding using chemical agents occurs only in a reactive system, e.g. a crosslinkable dispersion. Normal polymer bonding as it happens with non-reactive polymer binders (e.g. fibers, adhesives or lattices) is a physical process.
An uneven or irregular web that gives a cloud-like appearance. Also referred to as WINDOWS.
The formation of a nonwoven web through the concurrent use of elements from at least two different web formation technologies.
Application of a liquid material to one or both surfaces of a fabric, which is followed by drying or curing.
The resistance of like materials to be separated from one another. Examples are: The tendency of fibers to adhere to each other during processing, the resistance of a web to being pulled apart, and the resistance of a component of a laminate to being torn apart when the adhesive interface in the laminate is being stressed.
In carding, the part of the process that removes neps and straightens the fibers.
Combination of two or more distinct materials having a recognizable interface between them.
Term used when the essential part of the composite can be identified as a nonwoven material. If the essential part can not be identified, the term composite nonwoven is used when the mass of the nonwoven content is greater than the mass of any other component material.
A fiber of unending length, usually made by extruding a plastic or polymer solution through a hole in a die called a spinneret.
An organization that manufactures finished products from fabrics supplied in rolls; or provides intermediate processing steps such as slitting, dyeing and printing.
A polymer chain made up of monomeric units from more than one monomer, e.g. vinyl acetate / ethylene polymers.
An electrostatic charge applied to some filter media to increase the initial filtration properties of the filter.
A unicellular, natural fiber composed of an almost pure cellulose. As taken from plants, the fiber is found in lengths of 8 mm – 50 mm. For marketing, the fibers are graded and classified for length, strength and color.
The degree to which a fabric hides an underlying structure.
A lightweight nonwoven material used to contain and conceal an underlying core material. Examples are the facing materials that cover the absorbent cores of diapers, sanitary napkins and adult incontinence products.
A quality in a fabric imparted by wrinkling or embossing to give a crimped surface and greater fabric bulk.
The waviness of a fiber. Crimp amplitude is the height of the wave with reference to the straight uncrimped fiber.
CRIMP FREQUENCY OR LEVEL
The number of crimps per unit of length.
CROSS DIRECTION, CROSS MACHINE DIRECTION (CD, CMD, XMD)
The width direction, within the plane of the fabric, that is perpendicular to the direction in which the fabric is being produced by the machine.
Forming a multilayer web on to a conveyor belt by laying thereon a web back and forth at right angles to the direction in which the conveyor belt travels. The orientation of the fibers is dependent on the speed of the web delivery, the speed of the conveyor belt, and the width of the final web. Cross-lapping balances the MD (machine-direction) and CD (cross-direction) properties of the nonwoven. The WEB coming directly from a card has fibers and strength mostly oriented in the MD. A balanced cross-lapped web will have equal strength and elongation on both the MD and CD. Depending on the relative speed of the conveyors, cross-lapped webs may also be stronger in the MD or CD, by design.
CROSS-LAID, CROSS LAPPED
A web of fibers, formed by cross-laying or cross-lapping. A variable percentage of the fibers are oriented in both the MD and CD directions, providing more ISOTROPIC physical properties than a PARALLEL-LAID web.
A machine used to fold or layer fiber webs across their widths. The crosslapper provides webs with both machine direction and cross direction fiber orientation, can change web width, or web weight.
The outline profile of a cut end of a fiber when it is cut perpendicular to its long axis. These profiles can be round, oval, irregular or complex shapes depending on the shape of the die used to extrude the synthetic fiber; or for a natural fiber, depending on its growth pattern.
Orderly arrangement of molecules and polymer chains in a fiber or plastic.
A process by which resins, binders or plastics are set into or onto fabrics, usually by heating, to cause them to stay in place. The setting may occur by removing solvent or by crosslinking so as to make them insoluble.
A brand name for POLYESTER.
Weight in grams of 10,000 meters of a fiber. It is one-tenth of a tex (see Te x).
Tendency of a fabric to be pulled apart (layer separation) by normal surface forces or shear tensions.
The measure of a mass per unit length of a fiber. Denier is numerically equal to the mass in grams of 9000 meters of material. Low numbers indicate fine fiber sizes and high numbers indicate coarse fibers.
Mass per unit volume, i.e. grams/cubic centimeter. Density is different that BASIS WEIGHT, which is mass per square area, not cubic volume.
A filter medium which is thick and captures particles within the media. See also, SURFACE FILTER.
- (verb) The term used for removing a finished fabric from the machine: Doff the roll, or doffing the roll.
- (noun) In some regions, the term also refers to the roll of finished material removed from the machine.
A filter media made from diatoms, which are fossils that collect at the bottom of sea beds in prehistoric seas. Also known as “kieselguhr,” the material is characterized by pores and cavities capable of capturing and retaining contaminants.
A system to produce a thin filament of molten polymer in spunlaid and melt blown technology. A small annular orifice for spinning man-made fibers.
The movement of molecules or ions through a solution or material in response to differential concentrations or repulsive or attractive forces.
The ability of a fabric to maintain or resume its original geometric configuration.
Immersion of a textile in a finishing liquid (dip) such as dye or binder softener to improve its adhesion or water repellent properties.
The last cylinder of a card from which the sheet of fibers that has been formed is removed by a comb (doffer comb or roll).
Dioctylphthalate (diethyhexyphospate) is a viscous liquid that is heated into an aerosol in the critical particle range to challenge a filter. The aerosol’s presence upstream of the filter and downstream are measured to determine the media’s efficiency. DOP is used to measure HEPA and ULPA media performance.
The ability of a fabric to fold on itself and to conform to the shape of the article it covers.
A process of stretching a filament after it has been formed so as to reduce its diameter. At the same time, the molecules of the filament are oriented, thereby making it stronger. The ratio of the final length to the initial length is called the draw ratio.
DRY FORMING (DRY LAYING)
A process for making a nonwoven web from dry fiber. These terms apply to the formation of carded webs, as well as to the air laying formation of random webs.
A web of fibers produced by dry-laying.
A drylaid web bonded by one or more techniques to provide fabric integrity.
The ability of a filter device or media to remove particulate of a certain size from a liquid or gaseous fluid by measuring the concentration of the particles upstream and downstream of the device or media.
The ability of a strained material to recover its original size and shape immediately after removal of the stress that causes deformation.
Polymers having the rubbery qualities of stretch and recovery.
A web produced by an electrostatic process. Forming a web of fibers, especially BONDING microfibers, by means of an electrostatic field from a polymer solution or emulsion, or from a polymer melt.
The deformation in the direction of load caused by a tensile force. Elongation is generally expressed as a ratio of the length of the stretched material as a percentage to the length of the unstretched material. Elongation may be determined by the degree of stretch under a specific load or the point where the stretched material breaks.
ELONGATION AT BREAK
The point at which the last component of the stretched material breaks.
A process whereby a pattern is pressed into a film or fabric, usually by passing the material between rolls with little clearance and where one or both rolls have a raised design. At least one of the rolls is usually heated.
A suspension of finely divided liquid droplets within another liquid (see DISPERSION).
A method of forming a fabric by wrapping or knotting fibers in a web about each other by mechanical means, or by use of jets of pressurized air or water, so as to bond the fibers (see MECHANICAL BONDING).
A process by which a heated polymer is forced through an orifice to form a molten stream that is cooled to form a fiber. Examples of this process are Polypropylene and Polyester.
Alternatively, a solution of polymer can be forced through an orifice into a solvent that causes the fiber to solidify. Examples are Kevlar and rayon.
A sheet structure made from fibers, filaments or yarns.
FACE FABRIC, FACING
A material that serves as the outermost layer of a composite and is exposed and visible.
In carding, prepares the fibers for transfer from the main cylinder to the doffer.
Cleans the fancy.
Top and bottom rolls in carding that receive the fibers from the opening and blending stages of the plant.
A sheet of matted fibers, bonded together by NEEDLEPUNCH, SPUNLACE, and/or a chemical process, and the application of moisture, heat, and pressure (see also NEEDLEFELT). In some regions felt and NONWOVEN are used interchangeable, though there are many other types of nonwovens.
The basic threadlike structure from which nonwovens, yarns and textiles are made.
It differs from a particle by having a length at least 100 times its width. NATURAL FIBERS are either of animal (wool, silk), vegetable (cotton, flax, jute) or mineral (asbestos) origin.
MAN-MADE FIBERS may be either polymers synthesized from chemical compounds (polyester, polypropylene, nylon, acrylic, etc.) modified natural polymers (rayon, acetate) or mineral (glass).
In a web, the orientation (random or parallel) of fibers and the uniformity of their arrangement.
Low density fiber constructions, used as filling and cushioning, for products like pillows, bras and quilts.
(See GLASS FIBER)
A fiber having a lower melting point than the matrix fiber which can ultimately be melted to act as a local binder/enforcement system.
To break up a plastic sheet into a fibrous web, or to break up fibers into smaller fibers.
A fiber of indefinite length (see CONTINUOUS FILAMENT).
A non-fibrous additive used in a fiber, binder or a film, to increase weight, replace more expensive polymer, or to change lustre, or opacity etc.
A material used to separate particles from their suspension in air or liquids.
Material that makes up a filter element. Media can be made of a variety of materials, fabric, metal, sand, fiber, ceramics, etc.
Substance added to fibers and webs in a posttreatment, to change their properties.
Examples are spin finishes (lubricants) and flame retardants.
Process usually carried out after a web has been formed and bonded. Examples are embossing, creping, softening, printing and dyeing.
The ability to burn slowly or to self-extinguish after the ignition source is removed.
The ability of a material to resist ignition and the propagation of a flame.
Modified spinlaying (spunlaid) method in which a solution of a polymer is extruded under conditions where, on emerging from the spinneret, solvent evaporation occurs so rapidly that the individual filaments are disrupted into a highly fibrillar form. These fibers are then deposited on a moving screen to form a web.
A web of fibers produced according to the flash spinning method.
Web of fibers produced by the flash spinning method and bonded by one or more techniques to provide fabric integrity.
A method of applying a velvet-like surface to a material by dusting, or electrostatically attracting, short fibers onto an adhesively coated surface. The short fibers are made by special cutting or grinding techniques.
An automotive industry fire resistance standard. It is a horizontal burn test in which the material must either not ignite or self-extinguish within a certain time/distance.
A form of CHEMICAL BONDING. Binding fibers in a web to form a fabric by applying adhesive in the form of a foam whose bubbles break quickly after being applied.
An aerosol of fine liquid or semi-solid droplets in a gas.
Feet per minute.
Melting or bonding together of fibers or fabrics.
Untangled fibers that protrude from a fabric’s surface or yarn.
A process, similar to a carding, used to form a web from textile waste materials and other course, rough fibers. The machine is known as a Garnet.
A fluid having extreme molecular mobility and no fixed dimensions. It diffuses and expands rapidly to occupy the space in which it is contained. It is the vapor or gaseous state of a substance.
A permeable fabric used in civil engineering construction projects such as paving, dams, embankments and drains for the purpose of soil reinforcement and stabilization, sedimentation control and erosion control, support and drainage.
GLASS FIBERS, FIBERGLASS
Formed by extruding and attenuating molten glass. Glass fiber is brittle, which limits its use to a small number of markets. The fiber has the characteristics of withstanding relatively high temperatures of 280-300°C as well as poor heat conductivity and therefore major markets are heat insulation and high temperature filtration. Its characteristics of resistance to mildew, moisture and many oxidizing agents, solvents, alkalis and acids heightens its importance in those end-uses. The fiber also has good electrical resistance properties.
A measure of the “effective strength” of a fabric; i.e., the strength of fibers in a specific width together with the additional strength contributed by adjacent fibers. Typically, grab strength is determined on a four-inch wide strip of fabric, with the tensile load applied at the midpoint of the fabric width through one-inch-wide jaw faces that are used to clamp the fabric.
GRAVURE PRINTING or BONDING
In the context of nonwoven web bonding, this refers to a method of CHEMICALLY BONDING a web of fibers using the gravure method of printing. The gravure system uses a solid roller that is engraved with numerous small indentations. In the bonding process, the roller is partially immersed into an adhesive resin solution. As the roller turns, the excess solution is removed by a doctor blade, which leaves only the adhesive binder solution in the roller’s indentations. An unbonded web is then squeezed against the gravure roller (generally by a rubber roller) and the resin penetrates the web by osmosis. The web is then dried to remove the water and the binder remains.
Generally refers to woven or knitted fabrics off the loom prior to bleaching, dyeing or finishing treatment. The term is occasionally used to describe nonwovens before a finishing treatment.
Grams per square meter.
Grams per square yard.
Qualities of a fabric perceived by touch, e.g. softness, firmness, stretch, resilience and drape.
The ability to resist degradation at high temperatures.
Process by which fibers or fabrics are heated to a final crimp or molecular configuration so as to minimize changes in shape during use.
A means of dissipating heat generated in a reaction normally within the reaction system.
The ability of a fabric to resist shrinking or stretching under a mechanical or chemical stress. This property is obtained by prior heat treatment or with a chemical additive.
The acronym for High Efficiency Particulate Air. These filters are designed for filtering gases, normally air, to an efficiency of 99.97% by trapping particles down to 0.3 microns in the DOP test.
A brand of ARAMID fiber produced by Kolon Industries.
General term for low density, thick or bulky fabrics, as compared to flat, paper-like fabrics.
A polymer chain made up of monomeric units from one monomer only e.g. polyethylene.
A solid material that melts quickly upon heating, then sets to a firm bond upon cooling. Used for almost instantaneous bonding.
Structure used to contain material prior to being fed into the process i.e. polypropylene polymer chips prior to fiber spinning.
The acronym applies to Heating, Ventilating and Air Conditioning systems that service air in an enclosed space, i.e., buildings, airplanes, cars, etc.
Method of bonding a web of fibers or filaments by entangling them by using high-pressure water jets. A preformed web is entangled by means of high pressure, columnar water jets. As the jets penetrate the web, fiber segments are carried by the highly turbulent fluid and become entangled. In addition to bonding the web, which needs little or no additional binder, the process can also be used to impart a pattern to the web. Also referred to as SPUNLACING.
A web bonded by hydroentanglement. It may additionally be bonded by other techniques.
Having an affinity for being wetted by water or for absorbing water.
Lacking the affinity for being wetted by water or for absorbing water.
The ability to absorb moisture from the atmosphere, a property that fibers have in varying degrees.
The beginning of combustion.
The process in which particles are removed from an airstream because of the inertia. As an air containing particle flows toward a filter fiber or other collecting surface, the particle does not follow the air streamlines because of its inertia. Instead it moves in a straight line, colliding with the filter fiber or surface to which it may become attached.
Materials for non-apparel and non-decorative uses. Examples are wipes, cable wrap and geotextiles.
A material’s resistance to small deformations, defined as the slope of the stress-strain curve at the origin and sometimes used to indicate fiber stiffness.
INSTRON TENSILE TESTER
High precision electronic test equipment that measures the elongation or shortening of materials while forces such as pulling or compression are applied.
A nonwoven used in garments to provide weight, support and stiffness.
Having the same physical properties in every direction in the plane of a fabric.
It is related to the random distribution of the fibers.
A brand of ARAMID fiber produced by DuPont de Nemours, Inc.
A layered material containing two or more sheets bonded together with an adhesive, foam or thermoplastic resin.
The name for a roller at the beginning of the fiber feed system of a card line. It is a highspeed, saw-toothed wire roll that grabs the tufts of fibers fed into the system and deposits the partially opened fibers onto the main card cylinder.
The properties of bulk and resilience of a fabric or batt.
The long direction within the plane of the fabric, that is the direction in which the fabric is being produced by the machine.
In carding carries the fibers to the worker and stripper rolls.
A class name for various types of fibers (and filaments) produced from fiber forming substances that may be:
1) Polymers synthesized from chemical compounds, e.g. acrylic, nylon, polyester, polyethylene, polyurethane, and polyvinyl fibers.
2) Modified or transformed natural polymers, e.g. alginic, and cellulose based fibers such as acetates and rayon.
3) Minerals, e.g. glass.
The term manmade usually refers to all chemically produced fibers to distinguish them from the truly natural fibers such as cotton, wool, silk, flax etc.
The quantity of matter a body or article contains.
An array of fibers.
A non-glossy finish to a web.
A method of bonding a web of fibers by entangling them. This can be achieved by needling, stitching with fibers or by the use of high-pressure air or water jets.
Synonymous with filter material. “Media” is the plural of “medium.” It is common today to use media as the singular and “medias” as the plural.
A method in which a molten polymer is extruded into a high velocity hot gas stream that converts it into fibers. The molten plastic is blown with hot, high velocity gas through the extruder die lips. The filaments exiting from the extruder are attenuated during their formation until they break. The fibers break into short lengths rather than being continuous as those formed in spunlaid nonwovens. The short fibers thereby created are spread with cool quench air onto a moving belt called a forming fabric or onto a drum, where they bond to each other to form a white opaque, fine fiber web.
A web produced by meltblowing.
A meltblown web bonded by one or more techniques to provide fabric integrity.
Production of filaments by melting and extruding polymer. It is a general term that encompasses both SPUNLAID (SPUNBOND), MELTBLOWN, and FLASHSPUN nonwoven technologies, as well as filament yarns.
A permeable or semi-permeable membrane made of metal, polymer or other materials. These filters are capable of separating micron and sub-micron size particles from liquids and gases.
META-ARAMID (See ARAMID)
One millionth of a meter. In the context of nonwovens, the micron unit of measure is generally used to describe the width of low denier fibers, such as melt blown filaments, and the nominal filtration efficiency of a filter media. The abbreviated form is μm.
One thousandth of an inch. Used to measure the diameter of fibers and the thickness of films.
The amount of force it takes to stretch a material a unit distance. It is a measure of elasticity. An extensible material or fiber has a low modulus. Stiff materials have a high modulus.
A single filament of fiber.
Small molecules that can be linked together to produce polymers.
MOISTURE REGAIN (OR REGAIN)
Percentage of moisture in a fiber or fabric after it is equilibrated in a standard humidity.
Narrowing in width of a fabric, fiber or film when it is stretched.
A sheet of fibers (generally man-made) bonded by needling.
Mechanically binding a web to form a fabric by puncturing the web with an array of barbed needles that carry tufts of the web’s own fibers in a vertical direction through the web.
Action of needles being inserted and withdrawn from a batt or web or article not necessarily to produce bonding.
Small knots of fibers that were not separated before forming the web.
The line of close contact between two cylinders between which a fabric or web passes.
A brand of ARAMID fiber produced by DuPont de Nemours, Inc.
A nonwoven is an engineered fibrous assembly, primarily planar, which has been given a designed level of structural integrity by physical and/or chemical means, excluding weaving, knitting or paper making.
The fibers may be of natural or man-made origin. They may also be staple or continuous filaments or be formed in situ.
A manufactured POLYAMIDE fiber in which the fiber forming substance is any long chain synthetic polyamide having recurring amide groups (-NH-CO-) as an integral part of the polymer chain. The two principal nylons are NYLON 66, which is polyhexamethylene diamine adipamide, and NYLON 6, which is polycaprolactam.
A manufactured fiber in which the fiber forming substance is any long chain synthetic polymer composed of at least 85% by weight of ethylene, propylene, or other olefin units. Olefin fibers combine light weight with high strength and abrasion resistance (see also POLYETHYLENE and POLYPROPYLENE).
Having an affinity for being wetted by oil or for absorbing oil.
Having an affinity for being wetted by oil or for absorbing oil.
A preliminary operation whereby staple fiber is separated sufficiently from its lap or baled condition so that it can be fed to the web forming part of the process.
- The lining up or parallelism of molecular chains in fibers and films.
- The alignment of fibers in a nonwoven material.
Applying a liquid or paste to a web by passing it between squeeze rollers or by dipping it in a bath that carries the liquid or paste.
Forming a web in such a way that the fibers or filaments are laid in directions roughly parallel with the machine direction.
A web where the fibers or filaments are laid roughly parallel to the machine direction. Parellel-laid webs exhibit higher strength and lower elongation in the MD vs. CD. See also CROSS-LAID.
A minute piece, part or portion of matter. It may be solid, semi-solid or liquid.
The quantity of particles in a given volume of fluid.
A metric unit of pressure used in measuring an air filter’s performance.
A term used in tear testing. It is the force required to break the fiber bonds of a nonwoven or other samples of textile materials.
The flow of a liquid through pores, pinholes or holes resulting from imperfections or degradations of a
PENETRATION (filtration context)
A measure, in percent, of particles of a given size that pass through a filter. If no particles pass through, then 100% were trapped. If 97% of particles are trapped, then penetration is 3%(100% – 97% = 3%) and the filter is 97% efficient. Penetration is used to measure the performance of high efficiency filters.
The ability to be penetrated by liquids or gases.
A method of bonding fibrous webs by physical means: mechanical and thermal treatments.
A machine that separates staple fiber and forms it into a lap so that it can be fed to a card.
A colored or white substance that is insoluble and finely divided. Used to color or to deluster a fiber, fabric or plastic.
The tendency of fibers to come loose from a fabric surface and form balled or matted particles of fiber.
(See SONIC BONDING)
A gas of positive ions and free electrons with approximately equal positive and negative charges.
A polymer with its additives. Also, the ability to be deformed and molded.
Chemical that imparts flexibility, stretch and workability to a fabric or a plastic.
Layers of web, fabric or components of a laminate.
Using heat and pressure in a discrete predetermined pattern to bind thermoplastic fibers to form a nonwoven fabric.
A synthetic polymer of a type made by the linkage of an amino group of one molecule and a carboxylic acid group of another, including many synthetic fibers such as NYLON.
A manufactured fiber in which the fiber forming substance is any long chain synthetic polymer composed of at least 85% by weight of an ester of dihydric alcohol and terephthalic acid. The polymer is produced by the reaction of ethylene glycol and terephthalic acid or its derivatives.
A manmade fiber made of polyethylene, usually in monofilament form although work has been done on continuous filament yarns and staple. Ethylene is polymerized at high pressures and the resulting polymer is melt spun and cold drawn. It may also be dry spun from xylene solution.
An olefin fiber made from polymers or co-polymers of propylene. Polypropylene fiber is produced by melt spinning the molten polymer followed by stretching to orient the fiber molecules.
A liquid or solid substance made by chemically linking macromolecules together in chains. High polymer denotes substances made from very long chains. Crosslinked polymer describes a substance in which there are molecular links between chains. Polymerization is the process for making these polymers.
An abbreviation of “parts per million.” It may be expressed by volume as ppm (v)or by mass as ppm (m).
The action of a solid or liquid separating from a solution because of a chemical or physical process or change that has rendered it insoluble.
A method of THERMALLY or CHEMICALLY BONDING a web in discrete regions of the web according to a predetermined pattern.
The pressure drop is the resistance to a fluid passing through a filter media at various flowrates.
The fabric into which a carpet is tufted.
Short cellulose fibers made from wood or cotton.
Acronym for Quality Assurance.
QUALITY CONTROL, QUALITY ASSURANCE
Maintenance of standards in products or services through testing and procedures.
Cooling of filaments after extrusion by carefully controlled airflow, common in SPUNLAID/SPUNBOND manufacturing systems.
Forming a web in such a way that the fibers or filaments are laid in essentially random directions.
A web in which the fibers are laid in essentially random directions.
A random laid web bonded by one or more techniques to provide fabric integrity. Random-Laid nonwovens generally have more ISOTROPIC physical properties than a PARALLEL-LAID nonwoven.
RATED FILTER CAPACITY
The specific quantity of fluid that a filter manufacturer recommends can be handled by a filter.
1) A manufactured fiber composed of regenerated cellulose, as well as manufactured fibers composed of regenerated cellulose in which substituents have replaced not more than 15% of the hydrogens of the hydroxyl groups.
2) Also, any manufactured cellulose fiber including, in some cases, fibers composed of cellulose acetate (see also VISCOSE fiber).
Rayon fibers include yarns and fibers made by the viscose process, the cuprammonium process and the now obsolete nitrocellulose and saponified acetate processes. Generally in the manufacture of rayon, cellulose derived from wood pulp, cotton linters, or other vegetable matter is dissolved into a viscose spinning solution. The solution is extruded into an acid-salt coagulating bath and drawn into continuous filaments.
RECONSTITUTED FIBER, REGENERATED (REGEN) FIBER
Fibers extruded from recovered and reprocessed waste polymer or blends of virgin and recovered waste polymer. Waste sources include recycled bottles, plastics, fiber, and other polymeric materials.
The ability to resist wetting and staining by materials and soils.
The ability of a fiber or fabric to spring back when crushed or wrinkled.
A solid or semisolid polymeric material.
A common method of web bonding by using chemical agents, which may include adhesive resins and solvents. Most common is resin bonding. Latex resins (adhesive) are applied to the web by a variety of methods: dipping the web into the latex and removing the excess, spraying, foaming or printing bonding. The resin is usually in a water-based solution, so this bonding process requires heat to remove the water to dry and set the binder into the fabric. See also CHEMICAL BONDING.
Fibers that are sourced from several areas and recycled into needle-punched materials often destined for padding or insulation. This material is often referred to as “SHODDY.”
Fabric rolled up on a core after it has been produced. It is described in terms of weight and width of the roll and the length of the material on the roll.
SATURATION BONDING, SATURATE BONDING
Binding fibers to form a fabric by saturating a web with an adhesive followed by drying and curing. A type of CHEMICAL BONDING.
A textile with an open structure, which may be woven, knit or NONWOVEN, added to reinforce weaker materials in a COMPOSITE. Often, any nonwoven used as a backing or support fabric in composite a is called a scrim, regardless of how it is constructed.
The term refers to the characteristic crunch when loose, bleached cotton or rayon is hand squeezed. The sound is described as the crunch of walking on fresh fallen snow.
Shoddy generally refers to a bulky and/or lofty nonwoven made from reclaimed fibers. It is often multi-colored, and is often used for padding and sound insulation.
Staple fibers less than 15mm long. Typically used in the wetlaid process to make a fabric or as fillers in the absorbent cores of disposable hygiene products.
A layer of material laminated to the underside of a carpet to lock in carpet tufts, improve abrasion resistance, dimensional stability and strength.
SECONDS, SECOND QUALITY
Imperfect materials that have various flaws, such as weight lower or higher than specified, poor bonding, inconsistent web formation, poor tensile strength, etc.
A reduction in length or width due to the effect of heat, moisture or chemical action.
A water or solvent suspension. Examples are titanium dioxide mixed with water for addition to polymers or fibers mixed with water for wet forming.
SLIT (TO -)
To cut lengthwise.
A slow flameless, smoking burning of a fabric.
Adding pigments or insoluble dyes into the polymer melt or spinning solution prior to extruding a manmade fiber.
SONIC BONDING, SONIC SEWING
Also known as ultrasonic bonding and pinsonic bonding, sonic bonding uses high frequency sound to generate localized heat through vibration and thereby cause thermoplastic fibers to bond to one another. Specially designed “horns” that vibrate at ultra-sonic frequencies adjacent to an “anvil”, often a hardened, patterned roller, with a substrate or composite passing between the horn and the anvil. The energy created by the horn imparts the anvil’s pattern onto the substrate creating BOND POINTS that alter the aesthetics and physical characteristics of the material.
A nonwoven fabric used to attract and/or contain fluids. The term is most commonly used to describe products that are used to clean-up environmental oil spills and around machinery in a workplace to capture oil and other fluids. Oleophilic fibers, such as from polypropylene, are widely used in these products.
Ratio of the mass of a material to the mass of an equal volume of water at 4oC. Most POLYMERS used in NONWOVENS have a specific gravity greater than 1 (they sink), however most olefins, such a POLYPROPYLENE, have a specific gravity of less than 1, so they float.
A lubricant applied to fibers to reduce friction and static during processing into yarns and fabrics.
A process by which filaments or fabrics made from filaments, are generated directly from the molten polymer (see MELT SPINNING).
A process by which fibers or filaments are drawn out and twisted together to produce a thread.
Intrinsic angular motion.
A disc or screen containing many small holes through which molten polymer is extruded to form filaments.
Combined spinning and drawing in one operation in melt spun fibers.
Method of forming a web in which a polymeric melt or solution is extruded through spinnerets to form filaments which are laid down on a moving screen.
The system in a spunbond operation between the spinneret and the laydown belt
Binding fibers to form a fabric by spraying with an adhesive and then calendaring, through-air bonding or otherwise drying and curing the adhesive. A type of CHEMICAL BONDING.
SPUNLACE, SPUNLACED FABRIC
A term initially used by DuPont, but now universally used to denote a hydroentangled fabric. See HYDROENTANGLING.
A method of forming a web in which a polymeric melt or solution is extruded through spinnerets to form filaments which are laid down on a moving screen. Melt spun forming processes include spunbond, flash spinning and melt blown. The most common polymers used are polypropylene, polyester and polyethylene.
A spunlaid web bonded by one or more techniques to provide fabric integrity.
Note: The hot filaments are still sufficiently molten to adhere to themselves and form bonds at their crossover points. The desired orientation of the filaments in the web is achieved by rotating the spinneret, by the application of electrical charges, by controlled air streams and by the speed of the forming wire. Additional bonding can be achieved by compaction or hot roll calendaring.
Natural fibers or cut lengths from manmade filaments.
The ability of a fabric to resist bending. It is related to flexural rigidity i.e. to modulus of elasticity and thickness.
A technique in which fibers in a web are bonded together by stitches sewn or knitted through A web to form a fabric.
A nonwoven produced by the stitch bonding process.
Elongation, deformation or change in the dimensions of a body as the result of applied stress, expressed either as a relative unit change, or as a percentage.
An external force applied to a body or internal force per unit cross sectional area resulting from the external force.
Graph showing the amount of deformation obtained as a function of the force applied and the point at which rupture or breakage occurs.
The ability of a fabric to grow in length when pulled.
STRIKE THROUGH TIME
The time taken for a known volume of liquid (e.g. simulated urine) applied to the surface of a test piece of nonwoven coverstock, which is in contact with an underlying standard absorbent pad, to pass through the nonwoven. The ‘strike through time’ test is only designed to compare strike through times of nonwoven coverstocks. It is not intended to simulate in-use conditions of finished products.
In carding, clothed rollers that clear the workers and return fiber to the main cylinder.
Fabric to which coatings or other fabrics are applied.
SUPERABSORBENT POLYMER (SAP)
A material that can absorb many times the amount of liquid normally absorbed by cellulosic materials such as cellulose pulp cotton and rayon. Used mostly in granular form, but now available in fibrous form.
Electrical charge on a fiber or a fabric.
The work necessary to increase the surface area of a liquid. Normally expressed in dynes per square centimeter. Dynes are units of work.
A thin filter material that retains contaminants on the surface. See also DEPTH FILTER.
Forces acting between the molecules making up the surface of a liquid, causing the surface to contract to a minimum. Since it is a measure of the attraction of a liquid for itself, it can be related to its ability to mix with other liquids or to wet other surfaces.
A chemical additive that changes the surface attraction between two liquids, or between a liquid and a solid, by changing the surface energy of one or both components.
A man-made fiber, usually from a molten polymer or a polymer in solution.
TACK, TACKIFIER, TACKY
Slightly sticky surface finish. Tacky finishes are often added to nonwovens to improve anti-slip characteristics, or to improve particle retention in filter medias.
TEAR RESISTANCE, TEAR STRENGTH
The force required to begin or to continue a tear in a fabric under specific conditions.
(The tear resistance of a nonwoven fabric is usually measured by the Trapezoidal Tear Test).
A measure of the strength of a fiber. The force exerted per unit linear density when tensile stress is applied. Expressed as Newton per tex. Newtons are units of force. Previously expressed as grams force per denier.
1) In general, the strength shown by a specimen subjected to tension as distinct from shearing stress, bending or twisting momentum.
2) Specifically, the maximum tensile stress expressed in force per unit cross sectional area of the unstrained specimen, e.g. Newtons per square millimeter.
A metric measure of the mass per unit length of a fiber. It is numerically equal to the mass in grams of one kilometer of the material. It is also equal to the denier divided by 9.
A term describing the surface effect of a fabric such as dull, lustrous, woolly, stiff, soft, fine, coarse, open, or close; the structural quality of a fabric.
A process for imparting crimp, crepe and bulk to fibers yarns and fabrics.
THERMAL BONDING, THERMOBONDING
A method of bonding a web of fibers in which a heat or ultrasonic treatment, with or without pressure, is used to activate a heat-sensitive material, which may be in the form of homofil fibers, bicomponent fibers, or as all or part of the web.
The bonding may be applied all over (through or area bonding) or restricted to predetermined discrete sites (point bonding).
Polymeric materials that have a melting temperature and can flow or be formed into desired shapes on the application of heat at or below the melting point.
Polymeric materials that become intractably hardened by exposure to heat and/or catalyst action.
The dimension of a sheet or lamina measured perpendicular to the plane of the sheet under a specific pressure.
A spun-out filament. A thin structure of twisted yarns.
A bonding system that that uses high temperature air to fuse the web’s fibers. There are two basic systems: blowing hot air through the web in a conveyor oven or passing heated air through the web on a rotating drum. Fabrics made from bicomponent fibers or blends of bicomponent and regular fiber are often bonded by through-air bonding systems. This method is sometimes referred to as air-through bonding.
A natural chemical compound (TiO2) often used to pigment polymers in the spinning process to add whiteness.
The permitted variation in the measurement of specified property, such as weight, strength, color, etc., that is being observed in a test method.
The moment of a system of forces tending to cause rotation.
Ability to absorb work. Commonly measured as the area under the stress/strain curve. The opposite of brittleness.
A bundle of continuous filaments. The form of most manmade filaments before being cut into staple.
The energy-absorbing capacity of a fiber, defined as the specific work of rupture and obtained by measuring the area under the stress-strain curve.
A bundle of continuous filaments – the form of most man-made filaments before being cut into staple.
A fiber that is made from three polymers that are physically or chemically different.
Make insertions of clumps of fibers into depressions in the base fabric to form a 3D structure with the tufts of fibers oriented in the vertical direction.
The acronym for Ultra Low Penetration Air (filter). Air filters made to ULPA standards have filtration efficiencies of 99.999% on 0.3 micron DOP particles.
The use of high frequency sound to generate localized heat through vibration and thereby cause thermoplastic fibers to bond to one another. See also SONIC BONDING.
A fiberfill material that has not had any form of bonding treatment.
A fabric having strength mostly in one direction, generally the machine direction.
The ability of a substance to be broken down by the action of the ultraviolet part of the light spectrum so it can be consumed by the environment.
Various chemicals or polymers added to the product that absorb the ultraviolet light or otherwise make the material resistant to ultraviolet degradation.
The ability to retain strength or other properties upon exposure to ultraviolet light.
The ability of a substance to be broken down by the action of the ultraviolet part of the light spectrum.
UNWIND, UNWINDER, UNWIND STAND
The name often given to the equipment from which a roll of fabric is unwound for further processing or converting.
VAN DER WAALS FORCES
The forces of attraction and repulsion between molecules caused by the electric fields of the electrons (negative) and the nuclei (positive). The forces of molecular attraction explain why particles adhere to a filter’s fiber.
A manufactured fiber of cellulose obtained by the ‘viscose’ process using cellulose xanthate dissolved in a dilute solution of sodium hydroxide and extrusion of the viscose ‘dope’ into an acid precipitation bath. See also RAYON FIBER.
The ability to resist wetting by water.
1) The wide film of fibers that is delivered from a card.
2) A similar product of other web forming equipment such as that formed by air or water deposition and used to make nonwoven fabrics.
3) A term loosely applied to lightweight nonwoven fabrics.
The process by which the fibers or fibrous materials are interlocked in order to provide the integrity or strength desired in the fabric structure.
The process by which individual fibers or fibrous materials are arranged in order to bring about the physical properties desired in the fabric structure.
The force experienced by a body as a result of the earth’s gravitational force.
Any similar force with which a body tends to a centre of attraction.
The heaviness of a body regarded as a property of it.
Formation of a web by filtering an aqueous suspension of fibers onto a screen belt or on to a perforated drum.
Forming a web from an aqueous dispersion of fibers by applying modified paper making techniques.
A fiber web produced by the wetlaying technique.
Wetlaid web bonded by one or more techniques to provide fabric integrity.
The resistance of a fabric to being torn when it is wet. Usually compared to its strength when dry.
Inconsistent coverage of fibers in a nonwoven web. See also CLOUDY.
Transport of liquid within an absorbent fabric, along the thickness of the fabric and within the plane of the fabric.
Cellulosic fibers used to make viscose rayon, paper and the absorbent cores of products such as diapers, sanitary towels and adult incontinence products.
Rolls in the carding process that comb out and disperse the fiber bundles.
Definitions found in this glossary are for reference only, and were gleaned from the following sources:
- Herrmann Debroux, 46
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1100 Crescent Green, Suite 115, Cary, NC 27518
Phone: 919-459-3700 Fax: 919-459-3701 Email: email@example.com
- Sommers Incorporated.