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Glossary of Terms

A

Acetate Fibers

A manufactured fiber in which the fiber-forming substance is cellulose acetate (Federal Trade Commission (FTC) definition). Acetate fibers are derived by treating pure cellulose, which has been extracted from vegetable matter and generally wood pulp or cotton linters, with acetic anhydride. The resulting product is dissolved in acetone and extruded into filaments and the acetone evaporated. Acetate fibers are moderately strong, generally soft and lustrous like rayon. Acetate staple and filament fibers are more commonly used in weaving operations supplying end-markets such as lingerie, blouses, dresses, men’s ties and other apparel. Acetate consumption by the nonwoven industry is relatively low. [1]

Activated Carbon

A form of carbon capable of removing certain gases from air or impurities from water. Carbon is obtained from certain materials, generally of vegetable origin, and activated to produce a porous structure with a large surface area and adsorptive properties. [1]

Adhesion

The force that holds different materials together at their interface. [1]

Advanced Flexible Materials

Innovative or technically advanced rolled goods.  These materials can be any of the nine material types (composite, extruded net, film, foam, foil, membrane, nonwoven, technical paper, and technical textile), range from soft to semi-ridge, and are supplied on cylindrical cores.  Many of these materials are used in medical, aerospace, and electronic applications, are revolutionizing the way finished goods are assembled, or provide superior performance to previous products with the same end market application. 

Air Permeability

The rate at which air flows through a fabric. [1]

Airlaid Nonwoven

A nonwoven material where the web forming process disperes fibers into a fast moving air stream and condenses them onto a moving screen by means of pressure or vacuum. [1]

Amorphous

Not crystalline. A random, rather than regular, arrangement of chains of molecules within regions of a polymer or fiber. At melting temperatures, all thermoplastic polymers are amorphous. [1] [3]

Anionic Compound

A chemical carrying a negative electrical charge. [1]

Anisotropic

Not having the same physical properties in every direction. In the plane of a material, it is related to a non-random distribution of fibres. Materials will exhibit different properties depending on the direction of the test. [1] [3]

Antioxidant

An additive that retards the deterioration of a material’s functional and aesthetic properties resulting from its reaction with the oxygen in air. Many antioxidants work by absorbing or reacting with the oxygen. [1] [3]

Antistat

An additive that reduces the accumulation or assists the dissipation of electrical charges that arise during the processing of fibers, fabrics and films, and during the use of products. [1]

ASTM

The acronym for American Society for Testing and Materials International. A consensus organization for developing standards and test methods. [1] [2] [3]

B

Back Coating

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 retardency to the fabric. [1]

Back Sheet

The exterior surface of a baby or adult diaper – generally made of film. The current trend isto improve absorbent products’ aesthetics by adding a nonwoven material to cover the film, giving the outside of the product a cloth-like hand. [1]

Backing

A web or other material that supports and reinforces the back of a product such as carpeting or wallpaper. [1]

Basis Weight

The weight of a unit area of fabric. Examples are ounces per square yard and grams per square meter. [1]

Bicomponent Fibers (bico)

Fibers made of two different polymers extruded into one filament (core within a sheath or side by side are examples). One type of bicomponent fiber is produced using two polymers so chosen that one component softens at a lower temperature to act as a binder while the other component maintains the web’s structural integrity. A second type of bicomponent fiber is splittable and with some form of mechanical energy applied, such as the hydroentangled technology, will separate into finer denier fibers. [1]

Binder

An adhesive substance used to bind a web of fibers together or bond one web to another. The adhesive can be in a solid form (powder, film or fiber), foam, or in liquid form (emulsion, dispersion, solution) to bond the constituent elements or enhance their adhesion. [1]

Binder Content

The weight of adhesive used to bond the fibers of a web together – usually expressed in dryweight as percent of the fabric weight. [1]

Binder Fiber

Fibers with lower melting points than other fibers with a higher softening point or non- melting fibers. Upon the application of heat and pressure, these fibers soften and adhere to other fibers in the web, thereby acting as a binder. Some binder fibers can be bicomponent. A solvent (e.g. water) can activate some binder fibers, which may not be thermoplastic. [1]

Biodegradable

The ability of a substance to be broken down by microorganisms such as bacteria. The substance is converted into basic elements such as carbon dioxide and water. [1] [3]

Bleaching

Chemical treatment with compounds that release chlorine or oxygen to increase the whiteness of fibers and fabrics. [1]

Blend

A combination of two or more fiber types in making yarn or fabrics. [1]

Bond Strength

Amount of force needed to separate layers in a laminated structure or to break the fiber-to-fiber bonds in a nonwoven. [1]

Bonding

The combination of two or more components into a multiple-layer composite by means of resins (e.g.adhesives or solvent) or physical (e.g. mechanical entanglement or thermal adherence). The bonding may be all over or restricted to predetermined, discrete sites. [1] [2]

Breathable

A material having significant permeability. This can be due to the inherent properties of the material, the presence of open cells throughout its mass, or to minute perforations. [3]

Bun

A segment of FPF cut off from continuously produced slabstock type of FPF. [2]

Bursting Strength

The force needed to rupture a material by distending it with force or pressure. [1] [3]

C

Calender

A machine used to bond sheets of fabric or film to each other or to create surface features on these sheets. It consists essentially of two or more heavy cylinders that impart heat and/or pressure to the sheets that are passed between them. The rollers can be mirror-smooth, embossed with a pattern or porous. [1] [3]

Calendering

A mechanical finishing process used to laminate and to produce special surface features such as high luster, glazing and embossed patterns. [1]

Caliper

The thickness of a material such as paper, film, or foil, measured under specified conditions in millionths of an inch. [3]

Card

A machine designed to separate fibers from 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 machine direction. The machine consists of a series of rolls and drums that are covered with many projecting wires or metal teeth. [1]

Carding

A process for making fibrous webs in which the fibers are aligned either parallel or randomly in the direction that the carding machine produces the web. [1]

Carrier Web

A fabric which supports and facilitates moving a fibrous material through a processing stage. [1]

Catalyst

A chemical that initiates or accelerates the rate of a chemical reaction, but is not itself changed by the reaction. [1] [3]

Cationic

A chemical carrying a positive electrical charge. [1]

Cellulosic Fibers

Made from plants that produce fibrous products based on polymers of the cellulose molecule. Cotton plants produce separate cellulose fibers. Wood pulp is made by mechanically and chemically separating wood fibers. Rayon is made by dissolving vegetable matter, generally wood pulp, in a solution and extruding the solution through spinnerets into a chemical bath that regenerates the filaments. Some other cellulosic fibers are flax, jute and ramie. [1]

Chemical Finishing

Processes that apply additives to change the aesthetic and functional properties of a material. Examples include the application of antioxidants, flame retardants, wetting agents, stain, and water repellents. [1]

Chemical Properties

The response of a fiber to chemical environments such as acids, bases, or solvents.

Cleanroom

An enclosed space or room with a ventilating system that cleans the air and reduces the concentration and size of airborne particles to certain levels.

Closed Cell Structure

Foam cells having intact cell membranes thereby reducing or eliminating passageways for airflow. [2]

Coating

Application of a liquid material to one or both surfaces of a fabric, which is followed by drying or curing. The objective might be protective, decorative, a primer for subsequent coatings, improved barrier properties, waterproofing, antistatic and so on. Coating does not usually include the application of a layer or ply of preformed dry material by laminating. [1] [3]

Coefficient of Friction (COF)

A measure of the slipperiness of a surface determined by observing the force required to pull a known weight over a surface. Static COF is the force required to initiate motion while dynamic COF is the force required to continue the movement of the one surface over the other. Static COF is always greater than dynamic COF. As a general rule, low coefficient of friction allows for lower power requirements and easier machining where flexible materials are being pulled over stationary machine parts. However too low a COF can also result in telescoping rolls and packages that will slide at very low angles. [3]

Cohesion

The resistance of like materials to being separated from one another. Examples include: 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. [1]

Colorfastness

The ability of a textile material to retain its color when exposed to conditions (washing, drycleaning, sunlight, etc.) that can remove or destroy color. [1]

Combing

In carding, the part of the process that removes neps and aligns the fibers. [1]

Composite

Combination of two or more distinct materials with a recognizable interface between the materials.  The three main types of composites are coated materials, laminates, and tapes.  The multiple components allow the material to achieve a function that could not have been attained singularly by one part of the composite.  Composites are the most diverse material type.   [1]

Conditioning

A process of allowing materials to reach equilibrium with the moisture and temperature of the surrounding atmosphere. The atmosphere may be a standard such as 65 percent relative humidity and 70 degrees Fahrenheit, for testing purposes or other conditions that are optimum for manufacturing or processing. [1] [3]

Contaminant

Any solid, liquid or gas which can adversely affect machinery, a system or person. [1]

Continuous Filament

See Filament Fibers. [1]

Converter

An organization that takes raw materials supplied in rolls and provides an intermediate processing step, such as slitting, dyeing, coating, chemical finishes and printing. The fabric is then shipped to the finished products manufacturer. [1] [3]

Corona Treatment

A treatment applied to plastics and other materials to increase initial filtration properties of a filter, and increase receptiveness of adhesives or printing inks. An electrical discharge creates ozone, which in turn oxidizes the substrate surface and creates polar sites that contribute to strong bond formation. The treatment level is measured in dynes. [1] [3]

Corrosion

The deterioration of a material such as a metal by chemical activity. Corrosion may take place due to the action oxygen (oxidation) or of chemicals such as acids and bases, or to galvanic activity. Rusting is the conversion of iron to iron oxides by reaction with oxygen. [3]

Cover Stock

A lightweight nonwoven material used to contain and conceal an underlying core material. Examples are facing materials that cover the absorbent cores of diapers, sanitary napkins and adult incontinence products. The term cover stock now refers generally to facing material (topsheet), barrier leg cuff, back sheet, acquisition/transfer layer and stretchy panels. [1]

Creep

The increase in strain exhibited by a material when held at a constant stress. Unlike elastic deformation, the dimensional change is time dependent and non-recoverable. [1] [3]

Crepe

A quality in a fabric imparted by wrinkling or embossing to give crimped surface and greater fabric bulk. [1]

Crimp

The waviness of a fiber. Crimp amplitude is the height of the wave with reference to straight uncrimped fiber. Crimp frequency or level is the number of crimps per inch or centimeter. Crimp energy is the work needed to straighten out a crimped fiber. Crimp percent is the length difference between the crimped and stretched out fiber expressed as a percent. [1]

Cross Lapping

Process of layering a carded web on a conveyor, moving at right angles so the fibers are oriented in the cross direction increasing the cross directional strength of the fabric and the web weight. [1]

Cross Laying

Forming a multi-layered web on a conveyor belt by laying the web in a to and fro pattern 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 and the speed of the conveyor belt. [1]

Cross Machine Direction

The width dimension, within the plane of the fabric, that is perpendicular to the material's flow through a machine. [1] [3]

Cross-Linking

The chemical reactions that create bonds at several points between adjacent polymers. These cause the polymers to be less soluble and to undergo changes in elasticity and stiffness. [1] [3]

Cross-section

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 regular shapes – depending on the shape of the die used to extrude the synthetic fiber, or for a natural fiber, depending on its growth pattern. [1]

Crystalline

Orderly arrangement of molecules and polymer chains in a fiber or plastic. [1]

CSR

The central supply room of a hospital from which supply items are distributed. [1]

CSR Wrap

The covering material wrapped around surgical instrument trays to maintain a bacterial barrier in the hospital’s supply room storage area after sterilization. [1]

Curing

A process by which resins, binders or plastics are set into or onto materials, usually by heating, to cause them to stay in place. Curing implies a chemical change as compared to drying which indicates a loss of solvent. [1] [3]

D

Degradation

Deterioration of aesthetic and functional properties of a product - usually after being exposed for some time to heat, cold, light, or use. [1]

Degree of Polymerization

The average number of molecules in a polymer. [1]

Delamination

Separation or splitting of laminate layers caused by lack of adhesive, inadequate adhesion, or by mechanical disruption. [1] [3]

Denier

The measure of a weight per unit length of a fiber. Denier is numerically equal to the weight in grams of 9,000 meters of the material. Low numbers indicate fine fiber sizes and high numbers indicate coarse fiber sizes. The tex system is used in countries outside the United States. A tex is numerically equal to the weight in grams of one kilometer of fiber. It can be calculated by dividing the denier by nine. [1]

Density

A measurement of the mass per unit volume. [2] [3]

Diatomaceous Earth

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. [1]

Diffusion

The movement of molecules or ions through a solution or material in response to differential concentrations or repulsive or attractive forces. [1] [3]

Dimensional Stability

The ability of a material to maintain or resume its original geometric configuration when exposed to changes in temperature and stability. [1] [3]

DIN

Deutches Institut fur Normung or The German Institute for Standardization, which establishes standards for classifying and testing filters. [1]

Dipping

Immersion of a textile in a finishing liquid (dip) such as dye or binder softener to improve its adhesion or water repellent properties. [1]

Discontinuity

A lack of continuity or cohesion; an interruption in the normal physical structure of a material or a product. [3]

Dispersion

A distribution of small particles in a medium. It also describes the uniform suspension of solid particles in a liquid medium. [1] [3]

Disposables

A general classification of end-markets where the product made from the nonwoven has a relatively short life. Examples of some of the major categories are cover stock for baby diapers and sanitary napkins, wipes, fabric softener, medical apparel and associated items and filters. [1]

Drape

The ability of a fabric to fold on itself and to conform to the shape of the article it covers. [1]

Drylaid Nonwoven

A drylaid nonwoven is created by selecting and preparing the fiber, and forming and bonding the web. Two forms of web laying that are considered drylaid nonwovens are airlaid and carded materials. [2]

Durables

A general classification of end-markets for nonwoven materials. The main characteristic of these markets is that the end products have a long life and are more or less permanent. The larger of these markets include apparel interlining, automotive, home furnishings and bedding construction materials, carpeting, geotextiles and roofing material markets. [1]

Dynamic Fatigue

A durability test performed in the laboratory using roller-shear or pounding type mechanisms. [2]

E

Efficiency

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. [1]

Elasticity

The ability of a material to quickly recover its original dimensions after removal of a load that has caused deformation. [1] [3]

Elastomers

Polymers having qualities of stretch and recovery. Most commonly defined as being able to be stretched more than twice its original length and being able to return to its original length when the stress is released. [1] [3]

Electrical Conductivity

A measure of the rate that an electrical charge travels from one point to another in an electric field. [1]

Electrical Resistivity

The resistance to the movement of an electrical charge. [1]

Electron Beam Sterilization

Also known as E-beam (EB), this form of sterilization uses a flow of accelerated electrons that introduces levels of cross-linking, which induces terminal affects on living microorganisms.  The ionizing energy provides high dosage rates with low penetration.  This form of sterilization is well suited for low density products packaged in boxes, and is a highly cost efficient alternative to gamma irradiation [3].

Electrostatic Web Forming or Laying

Forming a web of fibers, especially microfibers, by means of an electrostatic field from a polymer solution or emulsion, or from a polymer melt. [1]

Elongation

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. [1] [3]

Embossing

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 has a raised design. At least one of the rolls is usually heated. [1] [3]

Emulsion

A homogenous mixture of finely divided liquid droplets within another liquid. [1] [3]

Entanglement

A method of forming a fabric by wrapping and knotting fibers in a web about each other, by mechanical means, or by the use of jets of pressurized water, so as to bond the fibers. See Hydroentangling. [1]

Equilibrium

A point at which a substance neither gains nor loses a stated property or condition. For example, paper when it is at equilibrium with the ambient relative humidity will neither lose or gain moisture and in doing so will not change in its physical properties. [3]

Ethylene Oxide

A gas used for sterilization of healthcare products. Packages must be porous to allow the gas to penetrate into and around the contained product. One advantage is that the process is done at comparatively low temperatures; typically about 60oC (140oF). [3]

Ethylene(vinyl acetate) (EVA)

A polar copolymer of ethylene and vinyl acetate, retaining some of the properties of polyethylene but with increased flexibility, elongation, and impact resistance. Copolymers containing less than 5% vinyl acetate are defined as polyethylene or modified polyethylene. Above 50% vinyl acetate, they are considered vinyl acetate-ethylene (VAE) copolymers. The addition of vinyl acetate reduces polymer crystallinity, which increases flexibility and reduces stiffness. EVA has high clarity, puncture resistance, impact strength, and low heat-seal temperature. EVA is frequently specified as the extrusion coating on polypropylene, poly(ethylene terephthalate), and aluminum foil to provide good heat-seals at high converting rates, or as the adhesive layer in some laminates. EVA is the base or backbone polymer of many hot-melt adhesive formulations. EVA is used to make color concentrates for plastics processing on account of its ability to wet-out pigments. [3]

Ethylene(vinyl alcohol) (EVOH)

Can be regarded as a copolymer of polyethylene to which varying amounts of the -OH functional group have been added. EVOH is one of the best polymeric oxygen barriers available to packagers. However, its susceptibility to water requires that for most applications it be laminated or coextruded into a protective sandwich with materials that will keep the EVOH layer away from water. [3]

ETO

Ethylene Oxide sterilization is used when products cannot withstand gamma irradiation or high temperature steam processes.  This process is the most costly and time consuming form of sterilization, so many product developers aim to design a product around this parameter.  ETO has four variables that can be altered to effectively sterilize a product: gas concentration, humidity, temperature, and time.  The process can be divided into three main steps which are pre-conditioning, sterilizer, and degasser.  The ethylene oxide chemical is an alkylating agent that disrupts the DNA of a microorganism making it incapable of reproducing.

Evaporation

The change from a liquid state to a gaseous state, as when a liquid boils or a solvent leaves a base formulation such as an ink or an adhesive. [3]

Exothermic

A chemical reaction that produces heat. [3]

Extruded Film

Generally used to describe film made by the cast extrusion method. [3]

Extruded Net

A strong mesh material that is created by extruding thermoplastic polymer pellets in a melting and pressurizing process.  A die is then used to form the extruded material into its desired structure.  The formed netting is cooled and hardens into its final shape.  Common extruded net patterns are diamonds or squares.

Extrusion

The process of forming a thermoplastic film, or profile by forcing the polymer through a shaped die or orifice to form a molten stream that is immediately chilled. A solution of the polymer can also be forced through the orifice into a solvent that causes the fiber to solidify. [1] [3]

Extrusion Blown Film

The continuous manufacture of thin film by extruding and then inflating a bubble of molten resin. [3]

Extrusion Cast Film

Film made by extruding a thin curtain of thermoplastic melt onto a highly polished chilled drum. After the film solidifies, it is edge trimmed and wound into rolls for further processing. [3]

F

Face Area

The area of a media used in air or liquid filters. [1]

Failure Analysis

A formal analysis that attempts to define the paths leading to failure and what should be done to prevent it. [3]

Failure, fatigue

The failure that occurs as a result of a number of repetitions of a load as opposed to creep which is a failure caused by the continuous application of a load. [3]

Fiber

A unit of matter characterized by a high ratio of length-to-width. Material which can be spun into yarn or made into fabric by interlacing (weaving), interlooping (knitting), or interlocking (bonding). Discontinuous fibers are referred to as “staple fibers” with lengths designated in inches or millimeters. Typical textile fibers have length-to-width ratios in the order of 1000 to 1, are longer than one inch, have diameters greater than 10 microns, and mass-per-unit-length (linear density) values in the order of one gram per thousand meters. [1]

Fiber Distribution

In a web, the orientation (random or parallel) of fibers and the uniformity of their arrangement. [1]

Fiber Variant

A man-made fiber type derived through the use of additives or modification of the polymer chemistry or fiber surface. Fiber variants exhibit or emphasize specific properties and are intended for focused end-uses or specialized applications. The modification may consist of adding end or side groups to the fiber forming polymer, altering spin finish, changing spinneret geometry, or varying any combination of controllable manufacturing parameters. [1]

Fiberfill

Low density fiber construction, used as filling and cushioning, for products like pillows, apparel and quilts made from synthetic fibers. The most common fiber used for fiberfill purposes is virgin polyester. [1]

Fibrillate

The break up of a plastic sheet into a fibrous sheet. The term can also mean breaking fibers into smaller fibers, such as the splitting of a bicomponent fiber. [1]

Filament Fibers

Filaments are extruded fibers produced from a variety of polymers. Filaments are continuous fibers that are produced by forcing a molten polymer through a spinneret. If cut to a shorter length, say 3.8 cm, the term filament fiber changes to “staple” fiber. [1]

Filler

A nonfibrous additive used in a fiber to increase its weight, replace a more expensive polymer or change luster and opacity. It is also non-fibrous materials, such as insoluble clay, gypsum, starch or gum added to a fabric to increase its weight or appearance. [1]

Film

Generally used to describe a thin plastic material usually not more than 76 micrometres (0.003 inch) thick. Typically, films are used as a semi-permeable barrier layer between two different environments, or acts as a support layer for materials with less structural stability.  There is a large range of finishes that can be used to further customize the function of the material including structural and surface changes.  [3]

Film, antifog

A film that has been treated so that moisture droplets do not accumulate on the surface. [3]

Filter Media

Material that makes up the filter element. Media can be made of a variety of materials, woven metal, sand, fiber, ceramics, etc. [1]

Finish (After Treatment)

Chemical or mechanical processes carried out after a web has been formed and bonded to enhance functional or aesthetic properties. Examples are embossing, crêping, softening, printing and dyeing. The term also includes slitting to narrower widths and rewinding to desired roll lengths. [1]

Flame Resistance

The property of a material to resist ignition, burn slowly or to self-extinguish after the ignition source is removed. [1]

Flame Retardent

A chemical used to impart flame resistance. The chemical can be added at the time the fibers are spun or added to the fabric though a finishing process. [1]

Flammability

The characteristics of a material that describe the relative ease for a fabric to ignite and sustain combustion. According to Interstate Commerce Commission regulation, liquids are flammable if their flash point is (27oC, 80oF) or lower. [1] [3]

Flash Dry

Drying or curing by the short duration application of high heat. [3]

Flex Fatigue

The loss of material firmness after flexing the material a predetermiend number of cycles. [2]

Flexural Strength

The ability of a material to withstand breakage by folding. Flexing strength may be measured by a test to determine the number of folds required to cause failure.

Flocking

A method of applying a velvet surface to a material by dusting, or electrostatically attracting, short fibers onto an adhesive coated surface. The short fibers are made by grinding or cutting. [1] [3]

Fluorescent

The property of a coloring agent that shifts ultra violet wavelengths into the visible light spectrum. Fluorescent agents are used to create various unusually bright day-glo type colors. [3]

Foam

A porous material that is composed of polymers with masses of gaseous air pockets within them.  These gas pockets can be closed, forming closed-cell foam, or the air pockets can be open, creating open-celled or reticulated foam.  In its formation process the desired polymers and additives are mixed together, poured, and allowed to cure and rise into its final shape.

Foam Bonding

A method for applying a resin to a loose web to bind the fibers. The resin is turned into a foam which then coats the fibers. An advantage of foam bonding is that little to no water is used in the binder thus requiring less heat energy and time to dry and cure the binder. [1]

Foil

An unsupported thin metal sheet, typically aluminum, less than 152 micrometers (0.006 inch) thick. Traditionally, an annealing (heat treatment) process was used to create foils, but it has become common practice to use a continuous casting process. The continuous casting process increases production efficacy because the timely annealing process is not used in this method.  Foils are commonly used as an impermeable barrier layer between two environments. [3]

Food and Drug Administration (FDA)

The U.S. agency within the Department of Health, Education and Welfare that is concerned with the safety of products marketed for consumer use, particularly those substances that might be ingested, applied to the skin, or used in therapy or prostheses. [3]

Free Sheets

A paper that is free of groundwood pulps. A paper made entirely from chemical pulps. [3]

Fusing

To join two surfaces by heating them to their softening or melting point. [1] [3]

G

Gamma Irradiation

An isotope, commonly Cobalt 60, emits high-energy photons that ionize a product.  The effects of the ionization cause damages to the DNA structure resulting in death of the microorganism or makes it incapable of reproduction.  The effects of the high frequency electromagnetic radiation does not create any damaging or harmful side effects to the end user of the product. 

Gas

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. [1]

Gas Sterilization

In medical packaging, the process of sterilizing flexible packaging using ethylene oxide gas. See Ethylene Oxide. [3]

Gauge

A unit of thickness measure expressed by a number that has a dimensional equivalent that varies for different materials and for different standards. When measuring the thickness of a film, 100 gauge = 0.001 inch. Thus, a 75-gauge film would be 0.00075 inch thick. In ISO units, film gauge is expressed in micrometres. [3]

Gel

A jelly-like material formed by coagulation of a colloidal liquid. [3]

Glass Fiber

Formed by extruding and attenuating molten glass. Glass fiber is brittle, which limits its use to a small number of markets. The fiber is capable of withstanding relatively high temperatures of 280-300°C and exhibits poor heat conductivity. Therefore major markets include 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. [1]

Glass Transition Temperature

The temperature at which a plastic passes from a harder, stiffer phase to a softer, more rubbery or leathery state. Designated by Tg, it is usually determined by observing changes in the rate of physical change (for example, the rate of expansion) rather than a visible change of state. Tg is thought to occur at the point where the polymer chains exhibit segmental mobility. [3]

Glassine

A smooth, dense, glossy, translucent paper made from highly beaten chemical pulps. The dense packing of finely divided fibers results in very low porosity. Often used where resistance to grease is required, hence it is often called greaseproof paper. [3]

Good Manufacturing Practice (GMP)

Good manufacturing practice implies that the entire manufacturing procedure for a product has been designed in such a way as to produce a quality product that presents a minimum risk to the consumer. GMP will vary from industry to industry depending on the nature of the product being packaged. Many GMPs have been formalized and are required by law for critical industries such as food and pharmaceutical packaging. Typically these GMPs describe the kind of equipment to be used, its validation, manufacturing procedures, inspection types and frequencies, record keeping, container types and approvals, and registration of company and product. [3]

Grab Strength Test

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. [1]

Gravure Bonding

In the context of nonwoven web bonding, this refers to a method of 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. See Resin Bonding. [1]

H

Heat Resistance

The ability to resist degradation at high temperatures. The retention of useful properties when measured during heat exposure. Conventionally taken to be the maximum temperature that a material will withstand and still retain at least 50% of its physical properties when subjected to this temperature for a specified time.[1] [3]

Heat Setting

Process by which fibers, yarns or fabrics are heated to a final crimp or molecular configuration so as to minimize changes in shape during use. [1]

Heat Stabilized

The ability of a material to resist shrinking or stretching under mechanical or chemical stress. This property is obtained by prior heat-treatment or by use of a chemical additive. [1]

HEPA Filter

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. [1] [3]

Holes

Small perforations or openings of varying sizes in a fabric. [1]

Homogeneous

Of the same composition or construction throughout. [3]

Homopolymer

A polymer that is produced by the polymerization of a single monomer species. For example, ethylene polymerizes to produce polyethylene. [3]

Humidity, absolute

Absolute humidity is the actual weight of water vapor contained in a unit weight of air. See humidity, ambient. [3]

Humidity, ambient

The uncontrolled humidity present at any given time. See humidity, absolute. [3]

Hybrid

A nonwoven produced by incorporating the advantages of two or more nonwoven manufacturing systems to produce specialized nonwoven structures with properties unattainable by any single nonwoven process. [1]

Hydroentangling

See Spunlace Bonding. [1]

Hydrogen Peroxide

A bacteriostat commonly used to sterilize package components. Hydrogen peroxide has the advantage of decomposing to water and oxygen. Typically used to sterilize packaging in aseptic packaging systems. [3]

Hydrophilic

A material that exhibits a strong affinity or attraction for water; opposite of hydrophobic. [1] [3]

Hydrophobic

A material that exhibits a strong repellency or aversion to water; opposite of hydrophilic. [1] [3]

Hydroscopic

The ability to absorb moisture from the atmosphere, a property that fibers have in varying degrees. [1]

Hydrostatic Pressure

The pressure exerted equally in all directions at points within a confined fluid (liquid or gas.) [3]

I

Inhibitor

Any substance that slows or prevents chemical reactions or biological activity such as those described as corrosion, oxidation, mold, growth, and so on. [3]

Instron Tensile Tester

High precision electronic test instrument that measures the elongation, tensile strength, tear strength or resistance to compression of materials while pulling or compressing forces are applied. [1] [3]

Interface

The contact area between two materials. [3]

Interleave

To insert separate sheets of paper or other sheet material between stacked product sheets in order to facilitate handling, prevent blocking, or reduce abrasion and smudging. [3]

ISO

Acronym for the International Standards Organization based in Switzerland. [1]

Isothermal

A process, study, or measurement that is conducted at a single temperature. [3]

Isotropic

A material having the same physical properties in every direction in the plane of the material. It is related to random distribution of fibers in a fabric. [1]

K

Knitting

A method of producing a fabric by interlocking a series of loops of yarns or filaments. [1]

Kraft

A term derived from a German word meaning strength, applied to pulp, paper, or paperboard produced from virgin wood fibers extracted by the alkaline sulfate process. Unbleached kraft has a light brown appearance. [3]

L

Laminate

A layered material containing two or more sheets bonded together with an adhesive, foam or thermoplastic resin. [1] [2] [3]

Latex

Either a naturally occurring milky appearing fluid from rubber tree sap from which rubber is made or a dispersion of a synthetic polymer in water. Typically used as binders. [1] [2]

Length

The dimension in the direction of travel through a machine. [3]

Line

A series of machines and equipment sufficient for the conversion of materials or for their packaging into the product of sales. [3]

Linters

Short cotton fibers not removed from the cottonseed after the spinnable fibers are removed on first pass through the gin. Linters are cut from the seed. Linters are used to make cellulose- based chemicals and rayon. [1]

M

Machine Direction

The direction parallel to a material’s flow through a machine. Flow direction through a machine may impart directional properties to a material. [1] [3]

Material Composition

The polymer(s) that is used to create a material.  A material composition can be of natural or synthetic origin.  An example of a natural polymer is cellulose, or variations of the cellulose fiber.  A synthetic example is polymers from the polyolefin family.

Material Safety Data Sheets (MSDS)

A document describing all pertinent information regarding safety and health hazards that might be associated with a product, as well as precautions and protection measures. [3]

Mechanical Bonding

Bonding a web of fibers by entangling them. This can be achieved by needling, stitching them with fibers or by entangling them by high-pressure water jets. [1]

Mechanical Finishing

Changing the appearance or physical characteristics of a fabric by a mechanical process such as calendering, embossing, bulking, compacting and creping.

Medium

Medium is 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. [1]

Melt blowing

A nonwoven web forming process that extrudes and draws molten polymer resins with heated, high velocity air to form fine filaments. The filaments are cooled and collected as a web onto a moving screen. In some ways the process is similar to the spunbond process, but meltblown fibers are much finer and generally measured in microns. Meltblowing is a spunlaid process. The term is also spelled “meltblowing.” [1]

Melting Point

The temperature at which a solid changes to a liquid state. [1] [3]

Membrane

A permeable or semi-permeable matrix made of metal, polymer or other materials. These materials are capable of separating micron and sub-micron size particles from liquids and gases by retaining particles larger than the pores on the surface of the membrane.  The three main forms of filtration include microfiltration (MF), ultrafiltration (UF), and Nanofiltration (NF) or Reverse Osmosis (RO).  These levels refer to the size of the particles that are able to pass through the membrane material.  

Membrane Filter

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. [1]

Metallize

Applying a thin coating of metal to a nonmetallic surface by chemical deposition or by exposing the surface to vaporized metal in a vacuum chamber. [3]

Metric System

Any of several decimal systems of weights and measures that use the metre, kilogram, and second as basic units. While all are based on the decimal system, they vary somewhat on the choice of base values. Globally the preferred system is that described as the SI system (not metric or SI metric). [3]

Microperforation

Minute holes deliberately introduced into (usually) flexible substrates for those applications where a definite level of permeability is required. The holes can be produced by electrical discharge. [3]

Modulus

A modulus is a measure of a mechanical property of a material, most frequently a stiffness property, for example, compressive modulus, flexural modulus, shear modulus, modulus of elasticity, and modulus of resilience. [3]

Moisture Content

The amount of moisture in a material expressed as a percentage of the dry product weight. [1] [3]

Moisture Regain

Percentage of moisture in a fiber or material after it is equilibrated in a standard humidity and temperature. [1]

Moisture Vapor Transmission Rate (MVTR)

A measure of the rate that water vapor passes through a film, sheet or dimensional part. Transmission rates have been expressed in a variety of inch/pound, metric and mixed units and care should be taken to ensure the same units are being used in any comparisons. [3]

Mold

A variety of fungus growths commonly found on the surface of damp decaying organic matter or in warm moist places. It is characterized by a woolly or furry texture. [1]

Molecule

The smallest part of an element or compound that can exist separately without losing its chemical properties. [1] [3]

Monofilament

A single filament of fiber. [1]

Monomer

A chemical compound that can be polymerized. [1]

Mullen Burst Test

A test procedure that measures the pressure necessary to burst a rubber diaphragm through a specified area of substrate. The Mullen burst test at one time was the principle methodology for characterizing corrugated board. It has been largely replaced by an edge crush test for this purpose but does have other applications. [3]

N

Natural Fibers

Fibers made directly from animals, vegetables or minerals. Examples are silk, wool, cotton, flax, jute, ramie and asbestos. [1]

Needlepunched

Mechanically binding a web to form a fabric by penetrating the web with an array of barbed needles that carry tufts of the web’s own fibers in a vertical direction through the web. [1]

Neutral

The absence of acid or alkaline activity in a material. The presence of an equal concentration of hydrogen and hydroxyl ions. Materials having a pH of 7. [3]

Neutralize

The addition of chemicals such as buffering agents that will adjust the pH level of a substance to closer to 7. [3]

Newton

The metric unit of force. [3]

Nonconformity

A departure of a quality characteristic from its intended level or state. [3]

Nonwoven

A fabric made directly from a web of fiber, without the yarn preparation necessary for weaving and knitting. In a nonwoven, the assembly of textile fibers is held together 1) by mechanical interlocking in a random web or mat; 2) by fusing of the fibers, as in the case of thermoplastic fibers; or 3) by bonding with a cementing medium such as starch, casein, rubber latex, a cellulose derivative or synthetic resin. Initially, the fibers may be oriented in one direction or may be deposited in a random manner. This web or sheet is then bonded together by one of the methods described above. Fiber lengths can range from 0.25 inch to 6 inches for crimped fibers up to continuous filament in spunbonded fabrics. [1]

O

Olefin Fiber

A polymer whose structure is primarily based on hydrocarbon monomer units (for example, ethylene and propylene). These fibers are used widely by the nonwovens industry in disposable and durable end-uses. [1] [3]

Oleophilic

A substance that has an affinity to oil. [1]

Oleophobic

A substance that has little to no affinity for oil. [1]

Opacity

The ability of a material to stop the transmittance of light. Quantified as the amount of light transmission. The opacity of a material is based upon the ratio of diffused light reflectance of a material backed with a black body to the diffused reflectance of the same material backed with a white body. The higher the percent of opacity, the more opaque the material is said to be. [3]

Opaque

Descriptive of a material or substance that will not transmit light. Opposite of transparent. Materials that are neither opaque nor transparent are best described as translucent. [3]

Open Cell Structure

A permeable structure in flexible foam in which there is minimal barrier between cells, and gases or liquids can pass freely through the foam. [2]

Openness

A term describing how tightly or loosely packed a collection of fibers is in any space. [1]

Organic

Compound molecules that contain one or more carbon atoms. [1]

Orientation

1. The lining up or parallelism of molecular chains in fibers and films. 2. The alignment of fibers in a nonwoven material. 3. The process of mechanically stretching plastic film or parts in order to produce straightened and aligned molecules. If done in one direction like in the manufacture of plastic strapping and cast film, the material is said to be uni-, or monoaxially, oriented. If done in two directions, the film is biaxially oriented. Orientation markedly improves many physical properties. [1] [3]

Orientation, Biaxially

A material in which the molecular structure is highly oriented in both the machine and cross directions to improve various physical and barrier properties. [3]

Orifice

An opening; usually suggestive of some level of precision. [3]

Osmosis

The diffusion of solvent through a semipermeable membrane separating two miscible solutions that tends to equalize their concentrations. [3]

Oxidation

A chemical reaction involving combination with oxygen to form new compounds. [3]

P

Particle

A minute piece, part or portion of matter. It may be solid, semi-solid or liquid. [1]

Particle Count

The quantity of particles in a given volume of fluid. [1]

Pathogen

A microorganism capable of causing sickness or death. [3]

Peak Force

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. [1]

Peel Adhesion

The force required to peel a pressure-sensitive material from a standard test plate at a specified angle and rate. [3]

Peel Strength

The stress required to peel apart two adhesive-bonded surfaces

Penetration

A measure, in percent, of particles of a given size that pass through a substrate. 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 very high efficiency filters. [1] [3]

Permeability

The passage of liquids or gases through an essentially continuous material. Permeation rates usually are described as the rate of permeation for a given area, thickness, and time. Because of the wide choice of units, there are many different ways of expressing permeability. Care should be taken when comparing values, that the units of measure are identical. As a general rule, the permeation rate is inversely proportional to a material’s thickness. Doubling the thickness will approximately halve the permeation rate. [1] [3]

pH

A numerical scale from 1 to 14 for representing the acidity or alkalinity of an aqueous solution. Seven is neutral. Below 7 indicates increased acidity, above 7 indicates increasing alkalinity. Each unit step indicates a ten-fold increase of acidity or alkalinity. [3]

Pharmaceutical

A manufactured, processed, or compounded form of a drug. [3]

Physical Property

The response of a fiber to physical forces. [1]

Plasticizer

Chemical that increases flexibility, or extensibility, while reducing elastic modulus. A plasticizer may also reduce melt viscosityand lower the glass transition temperature. Most plasticizers are nonvolatile organic liquids or low-melting solids (for example dioctyl phthalate, diisooctyl phthalate, and diisodecyl phthalate) that function by reducing the normal intermolecular forces in a resin, thus permitting the macromolecules to slip past one another more freely. Poly(vinyl chloride) is the main user of plasticizers. [1] [3]

Pleating

The process of fan-folding materials to increase surface area. Commonly used for filter media to increase efficiency and reduce pressure drop. [1]

Ply

A single layer of a web, fabric or material of a multilayer laminate. [1] [3]

Point Bonding

Using heat and pressure in a discrete pattern to bind thermoplastic fibers to form a nonwoven fabric. [1]

Poly(vinyl chloride) (PVC)

Plastics based on resins made by polymerization of vinyl chloride or copolymerization of vinyl chloride with other unsaturated compounds, with vinyl chloride being the predominant component. Pure poly(vinyl chloride) is a difficult to process hard brittle material. For most flexible material applications it requires the addition of a plasticizer or to be copolymerized with vinyl acetate. [3]

Polyester (PET)

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 (FTC definition). The physical properties of polyester fiber are excellent strength, high abrasion and resilience with good chemical resistance to acids, solvents and oxidizing agents. [1]

Polyethylene (PE)

A polyolefin composed of polymers of ethylene. PE can be clear or translucent depending on density. It is a tough, waxy solid, that is unaffected by water and is inert to a large range of chemicals. PE is marketed in three general classifications: low-, medium-, and high-density as follows:


Density Range

  • Low-density PE: 0.910 to 0.925
  • Linear low density PE: 0.915 to 0.935
  • Medium-density PE: 0.926 to 0.941
  • High-density PE: 0.942 to 0.965

 

Linear low-density polyethylene is sometimes grouped with low-density polyethylene, even though there are significant property differences. [3]

Polylactic Acid (PLA)

A biodegradable polymer made from renewable resources (primarily corn-derived dextrose.) [3]

Polymer

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. [1] [3]

Polymerization

A chemical reaction in which the molecules of a monomer are linked together to form large molecules whose molecular weight is a multiple of that of the original substance. When two or more monomers are involved, the process is called copolymerization or heteropolymerization. [1] [3]

Polyolefin

A polymer formed by the polymerization of an olefin as the sole monomer. Including such monomers as ethylene, propylene or other olefins. [1] [3]

Polypropylene (PP)

A hydrocarbon polymer polymerized from propylene gas. One attractive physical characteristic of polypropylene is its specific gravity of less than one, which results in a larger area volume yield per kilogram or pound of resin or staple fiber compared to competitive fibers in the nonwoven industry. Polypropylene has a relatively low melt temperature which restrict its uses in many nonwoven markets, but it has good strength properties, softness, and chemical resistance to strong acids and alkalis. In the film markets, the material is mostly oriented (OPP) or biaxially oriented (BOPP). OPP film has excellent clarity, low elongation, good moisture-barrier properties, and good low-temperature performance. Polypropylene has a higher softening point than PE. [1] [3]

Polyurethane (PU)

A polymeric material made by the reaction of any of a group of isocyanates with any of a group of multifunctional glycols. Depending on the participating monomers, urethanes can be made that have a wide range of properties (for example, thermoplastic, thermoset, rigid, elastic, cellular, and so on). [3]

Porosity

The presence of pores or minute openings in a material. A material characteristic that allows free passage of air or liquid.One measurement is the rate of air movement through a test specimen. [3]

Post-Consumer Recyclate (PCR)

Recyclable material whose origin is in consumer waste as opposed to in-plant reprocessing, industrial waste, or commercial waste. [3]

Precipitate

An insoluble substance that forms in a solution. [3]

Pressure

The force per unit area that is acting on a real or imaginary surface. Common units of measure include pounds force per square inch and pascals. [3]

Pressure Drop

The pressure drop is the resistance to a fluid passing through a filter media at various flowrates. [1]

Pulp

Short cellulose fibers made from wood or cotton. [1] [3]

R

Radiation Sterilization

The process of sterilizing the contents of sealed packages containing foods or medical materials by exposing them to controlled levels of high-energy radiation, usually either gamma from a cobalt-60 source or electrons from guns. The process provides total destruction of microorganisms, is safe, is performed at ambient temperatures, and provides flavor advantages over some other methods of sterilizations. Radiation sterilization with gamma rays or electron beams cannot induce radioactivity in the treated material. [3]

Radiation, electron-beam (EB)

Magnetically accelerated electrons focused by electric fields are used for cross-linking polyethylene to improve modulus and temperature resistance, and to cure coatings and adhesives, eliminating the need for photoinitiators. Treatment levels must be controlled since overexposure will cause degradation. Electron beams also can be used to sterilize materials or products similar to gamma irradiation. [3]

Radiation, gamma

Electromagnetic energy emitted from radioactive materials such as cobalt (60) as they decay. Gamma radiations are similar to, but of much shorter wavelength (typically 0.03 nm) and much higher energy than X-rays. They are highly penetrating, capable of passing through several centimetres of lead. Gamma radiation is used to sterilize medical supplies; an advantage being that the product can be sterilized when already sealed in its packaging. Various food products also can be gamma irradiated to improve their keeping qualities. Gamma irradiation also is used to initiate cross-linking and other changes in polymeric materials. [3]

Rated Filter Capacity

The specific quantity of fluid that a filter manufacturer recommends can be handled by the filter. [1]

Rayon

A manufactured fiber composed of regenerated cellulose, as well as manufactured fibers composed of regenerated cellulose in which the substitutes have replaced not more than 15% of the hydrogen atoms of the hydroxyl group (FTC definition). Rayon is manufactured from the cellulose found in vegetable matter, the major source being wood pulp and cotton linters. The cellulose is dissolved into a viscose solution and then extruded through a wet-spinning system to coagulate the filaments. The principal physical properties of rayon is moderate strength, softness, luster, hydrophilic and ease of dyeing. [1]

Reconstituted Fibers

Fibers made from recovered waste polymer or blends of virgin and recovered waste polymer. [1]

Recovery

The amount of return to original dimension and properties of a material sample after a deforming force is removed. [2]

Relative Humidity

The ratio of actual amount of water that the air is holding to the maximum amount of water that air can retain without precipitation at a given temperature and pressure. It is also the ratio of the partial pressure of water vapor present to the vapor pressure of water at the prevailing temperature. Relative humidity (RH) is expressed as a percentage of saturation. [3]

Relaxation

The decay or relaxation of stress exhibited by a material when held at constant strain. [1]

Release

The force required to separate a pressure-sensitive adhesive from its release liner or carrier. [3]

Release Liner

A paper that has been coated with a release agent (an antiadhesive, most commonly silicone or fluoropolymer based) to prevent the formation of a permanent adhesive bond. Release papers are used to hold pressure-sensitive labels and to back adhesive tapes. [3]

Repellency

The ability to resist wetting and staining by materials and soils. [1]

Resilience

Ability of a material to recover its original shape and dimension after being distorted. [1] [2] [3]

Resin

Any of a group of solid or semi-solid organic materials of natural or synthetic origin. The material is generally of higher molecular weight, and with no definite melting point. The material is often used in plastics or production of synthetic fibers [1] [3]

Resin Bonding

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. This is sometimes referred to as “latex bonding.” [1]

S

Saturated

When used to describe a type of chemical bond or molecule, the bonding is saturated if no double or triple bonds exist, that is, each atom is joined within the molecule to other atoms only by single bonds. [3]

Scrim

A textile with an open structure, which may be woven or nonwoven, added to reinforce weaker materials. [1]

Shear

An action resulting from applied forces, which causes or tends to cause two neighboring parts of a body to slide relatively to each other in a direction parallel to their place of contact. [3]

Shear Strength

The ability of a material to withstand shear stress. [3]

Shear Stress

A stress applied to a material parallel to its plane. Tensile stress is a stress applied perpendicular to the plane. For example, an adhesive bond can be separated by pulling perpendicular or parallel to the adhesive layer. [3]

Sheet

A material that is in the form of a flat sheet as opposed to being wound into a roll. [3]

Short Fiber

Staple fiber less than 0.5 inches long. Typically used in wet laid processes, to make fabrics, or as fillers in absorbent cores. [1]

Shrinkage

A reduction in length or width due to the effect of heat, moisture or chemical action. [1]

Silicone Polymer

Polymers composed of molecular chains containing alternating silicon and oxygen atoms. These can be liquids or solids depending on the molecular weight and the groups attached to the chain. Silicones also can have widely differing properties. For example, some silicone compounds are able to be used as adhesives, while others are used as anti-adhesive or release agents. [3]

Slip

The property of a material having a relatively low coefficient of friction. [3]

Solvent

A liquid medium able to dissolve a substance and place it in solution. Solvents are widely used to dissolve solid resins in order to produce a fluid base, which might subsequently be used to manufacture adhesives, coatings, and inks. In other instances, solvents may be used to dilute, render more fluid, or control the viscosity of a composition. Major solvent family groups are alcohols, esters, glycol ethers, ketones, aliphatic and aromatic hydrocarbons, and chlorinated hydrocarbons. [3]

Specific Gravity

The ratio of the weight of a material to the weight of an equal volume of water at the same temperature. [1] [3]

Splice

Joining two pieces of web material to form a continuous web. Film splices may be butted or lapped using tape, adhesives, ultrasonic welding or other means. [3]

Spunbond

A spunlaid technology in which the filaments have been extruded, drawn and laid on a moving screen to form a web. The term is often interchanged with “spunlaid,” but the industry has conventionally adopted the spunbond or spunbonded term to denote a specific web forming process. This is to differentiate this web forming process from the other two forms of the spunlaid web forming, which are meltblown and flash spinning. [1]

Spunbond/Meltblown Composite

A multiple layer fabric that is generally made of various alternating layers of spunbond and meltblown webs: SMS, SMMS, SSMMS, etc. [1]

Spunlace Bonding

The method of bonding a web by interlocking and entangling the fibers about each other with high velocity streams of water (synonymous with Hydroentangling). The web or fabric may have other bonding methods in addition to spunlacing. Spunlacing, not to be confused with spunlaid, is generally produced from a web made up of staple fibers from a dry formed, carded system, but small quantities of spunlace bonding are done on production lines that use a wet laid forming process. A recent technical development is the production of a spunlaced nonwoven from a spunlaid, continuous filament web. [1]

Spunlaid

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. [1]

Static

An accumulation of electrical charge on the surface of fibers or fabrics due to its inadequate dissipation during processing or use. With reference to films, causes them to cling to one another or to other insulating surfaces as well as attracting atmospheric dust. [1] [3]

Steam Sterilization

A form of sterilization traditionally completed in an autoclave device which submits the products to pressurized steam at temperatures ranging from 121C to 134C.  This process takes between 3 to 15 minutes depending on the temperature needed to sterlize the products.  Once the steam phase is completed products must remain in the autoclave until they are dry to avoid re-contamination.  The final step is a cooling process where the products return to ambient room temperture.  This can take up to several hours.  For many materials this is not an effective form of sterilization because the high temperatures cause the raw materials to begin changing form.

Sterile

Free of any active or dormant viable microorganisms. [3]

Stiffness

The ability of a material to resist bending. It is related to fiber modulus or elasticity. [1] [3]

Stress-Strain Curve

Graph showing the amount of stretch or compression obtained as a function of the force applied and the point at which rupture or breakage occurs. [1]

Stretch

Extensibility of web materials under tension. Stretch usually is determined in tensile-testing equipment and is recorded as the percentage of extension at the point at which the sheet breaks.[1] [3]

Substrate

Material to which coatings or other materials are applied. [1] [3]

Superabsorbent (SAP)

A sorbent material that can absorb many times the amount of liquid ordinarily absorbed by cellulosic materials, such as wood pulp, cotton and rayon. [1]

Surface Charge

Electrical charge on a fiber or fabric. [1]

Surface Energy

The work necessary to increase the surface area of a liquid – generally expressed in dynes per square centimeter. Dynes are units of work. [1]

Surface Tension

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. [1] [3]

Surfactent

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 thus permitting easier bubble formation. [1] [2] [3]

Suspension

Dispersion of very fine particles of a solid or liquid in a liquid or gas, respectively, in which the suspended material is not actually dissolved, but will settle out on prolonged standing unless prevented by agitation or by the use of stabilizing agents. A suspension differs from a colloidal condition by this property of settling; a colloid does not settle. [3]

T

Tack

In adhesives, the amount of stickiness or pull resistance experienced when one attempts to separate two substrates while the adhesive is still in a viscous or fluid state. [3]

Tackifier

A substance such as a rosin ester that is added to synthetic resins or elastomeric adhesives to improve the initial tack and extend the tack range of the deposited adhesive film. [3]

Tape

A base material such as technical textile, paper, plastic, film, or other flexible composition coated on one or two sides with an adhesive. The base material may be reinforced with fiber. The adhesive may be water-remoistenable, pressure-sensitive, or other formulation. [3]

Tape, pressure-sensitive

A pressure-sensitive adhesive applied to a thin supporting web. The tape may be wound around itself or with more aggressive adhesives may be attached to a release paper. [3]

Tear Strength

A measure of the force required to continue a tear in a foam after a split or break has been started. This property is important in determining suitability of foam in applications where the material is sewed, stapled, or otherwise anchored to a solid substrate. Also important in demoldability. [2] [3]

Technical Paper

A material manufactured in thin sheets from the pulp of wood or other fibrous substances, unlike traditional paper, technical paper is manufactured for non-aesthetic purposes, where function is the primary criterion.  Technical paper is typically constructed using the traditional wetlaid process.

Technical Textile

A woven or knitted material with extremely precise dimensions.  Technical textiles are constructed from mono- and multi-filament polymer or fabric based yarns.  This material is similar in function to an extruded net, but greater precision can be reached through the weaving process.  The highly accurate dimensions of technical textiles make precise filtration a common application for this material. 

Tensile Strength

The strength of a material when exposed to a force operating to extend, stretch, or pull it apart, at a specified temperature and at a specified rate of stretching. It measures the stress a material can bear without breaking or tearing. [1] [2] [3]

Test Method

A procedure for the identification, measurement, and evaluation of one or more qualities of a material, product, system or service that produces a test result. [1]

Thermal Bonding

A technique for bonding a web of fibers in which a heat or ultrasonic treatment, with or without pressure, is used to activate a heat-sensitive material. The material may be in the form of homofil fibres, bicomponent fibers, fusable powders, as part of the web. The bonding may be applied all over (e.g. through or area bonding) or restricted to predetermined, discrete sites (e.g. point bonding). [1]

Thermoelasticity

Rubber-like elastic state of a normally rigid plastic resulting from an increase in temperature. [3]

Thermoplastic

Any fully reacted polymeric material that can be repeatedly softened to a melt form and resolidified to a solid shape without significant change in properties. Structurally, thermoplastics are characterized by the absence of crosslinking between polymer chains. [1] [3]

Thermoset

A plastic, once formed, that does not melt when reheated. The material is characterized by a high degree of crosslinked polymer chains. [1] [3]

Thickness

The dimension of a sheet or lamina measured perpendicular to the plane of the sheet. [1]

Tight Foam

Foam with many closed cells, resulting in low area flow measurements. [2]

Tolerance

The permitted maximum and minimum deviations in the measurement of specified property, such as weight, strength, elongation, etc., that is being observed in a test method. [1] [3]

Toughness

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. [1]

Toxicity

The degree to which a toxic or poisonous substance affects living organisms. Toxic substances used in the workplace must be described on Material Safety Data Sheets (MSDS) [3]

Trade Name

A name or term that is owned by registration of a copyright that identifies the product or service of a company. [3]

Transition Temperature

A temperature at which some radical change, usually a phase change, in the appearance or structure of a substance occurs. [1] [3]

Transparent

A material or substance that has a high degree of light transmission; i.e., clear enough to see through. [3]

U

Ultrasonic Bonding

The use of high frequency sound to generate localized heat through vibration and cause thermoplastic fibers to bond to one another. [1]

Unidirectional Material

A material has strength mostly in one direction, generally the machine direction. [1]

V

Validation

Testing the components of an operation to confirm that they are performing the function they are supposed to perform. [3]

Virgin Foam

Unfilled flexible slabstock foam that has not been processed in any manner other than cutting to shape. [2]

Virus

A semi-living, generally inert microscopic particle chiefly protein in composition. They replicate by entering a living cell and direct the cell to reproduce more viruses. The cell is usually destroyed as the new viruses are released to the surrounding environment. [1]

Viscoelasticity

A material’s behavior is classed as elastic if after deformation due to an applied stress the material returns to its original size (providing the material’s yield point has not been exceeded). A material that flows and deforms permanently when under stress is said to exhibit viscous flow. A material that exhibits elements of both behaviors is said to be viscoelastic. Elastic behavior is time independent, while viscous flow is time dependent. A plastic that is quickly bent and released will exhibit primarily elastic behavior. The same plastic bent (stressed) to a new shape and held there for a period of time will become permanently deformed. [3]

Viscose

See Rayon Fiber [1]

Viscosity

A measure of a fluid’s resistance to flow. Water would be classed as a low-viscosity fluid, while a syrup would have a high viscosity. Viscosity is measured in centipoise or pascal/seconds. [3]

Voids

The undesirable formation of large cavities or pockets in a foam structure. Voids are usually caused by poor moldability or incorrect mold filling. In the case of foam buns, voids occur when then blowing and polymerization reactions are out of balance. [2]

Volatile

Said of a material subject to rapid evaporation and that easily passes from a liquid to a gaseous state under ambient conditions. A material having a high vapor pressure at room temperature. [3]

W

Warp

The yarns that run in the machine direction of a woven fabric. [1]

Waste

Material trimmed and salvaged in the process of manufacture. [3]

Water Absorption

The percentage of water absorbed by a material in a given time. [3]

Water Blown

Foam in which the gas for expansion is carbon dioxide generated by the reaction between water and an isocyanate material. All flexible polyurethane foam is water blown, although auxiliary blowing agents are often used to obtain special physical properties. [2]

Waterproof

The material property that allows it to be in direct contact with water for extended periods without significant change in properties. [3]

Weight

The mass of a fabric expressed in grams per square meter or ounces per square yard.

Wet Strength

A measure of the physical strength properties of paper, adhesive bonds, or some other material or assembly when saturated with water, usually expressed as wet tensile strength, wet bursting strength, and so on. [1] [3]

Wetlaid

To distinguish nonwovens from papers, a wet laid material will be defined a nonwoven if: More than 50%, by mass, of its fibrous content is made up of fibers (excluding chemically digested vegetable fibers) with a length to diameter ratio greater than 300: or More than 30%, by mass of its fibrous content is made of fibers in “a” above and meet one or both of the following criteria: Length to diameter ratio of more than 600. The density of the fabric is less than 0.4 g/cc. [1]

Wetting

The ability of an adhesive, ink or coating to make contact and spread evenly over a substrate. Proper wetting is a function of the surface energy of the adhesive and the substrate. The adhesive must have attraction to the substrate at the molecular level for proper wetting to occur. [3]

Windows

The thin membranes formed between cell struts. Windows may be present (a closed-cell foam) or absent (an open-cell foam) depending on the particular foam chemistry used. [2]

Wood Pulp

Cellulosic fibers used to make viscose rayon, and paper. [1]

Y

Yarn

A continuous strand of fibers or filaments that are twisted together, to enable its conversion into a woven, knitted or braided fabric. [1]

Yield

The amount of product that can be produced from a given weight of material. However, because of density differences, the same weight of similar materials can produce different amounts of finished product. [1] [3]