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A - C



The wearing away by friction. As rubbing against another surface can damage glass filaments, they are coated with a size to prevent filament breakage during manufacturing and further processing.


See Cem-FIL®. 

Assembled roving

A collection of parallel strands assembled without intentional twist (according to ISO/DIS 13922).


Batch oven

Large temperature-controlled oven that, through heat cleaning, removes the organic materials applied to the glass filament surface. 


A big spool on which a large number of yarns or ends are wound parallel and used for various operations as slashing, weaving, knitting, laid scrim, multiaxial machine and more.


Operation in which yarn ends, pulled from several section beams, are combined by a beamer on a loom beam in order to supply the required number of warp ends specified by the fabric construction.

Binder, Binding agent

Mixture of chemical products (ingredients) applied to strands or filaments in order to hold them in a desired arrangement, for example, in chopped strand mat, continuous strand mat and surfacing mat (according to ISO/DIS 13922). 


The shipping package onto which textile strand or yarn is wound, and which can be used in various textile processing (also known as cops).


A planar flat or tubular fabric structure made by interlacing several yarns in such a manner that all yarns lie at an angle other than 0° or 90° to the length direction of the structure (according to ISO/DIS 13922).


A method of interlacing yarns or rovings (according to ISO/DIS 13922).


Platinum and rhodium alloy plate with several hundred holes, from which molten glass flows by gravity.


Cabled yarn

Yarn made from two or more plied yarns, which have been twisted together in a third twisting operation. A cabled yarn of “n” ends means that “n” plied yarns were used in its construction.


Primary package of glass filament strand wound on a tube (also called a sleeve) placed on the collet of a winder, during the forming stage.

Chopped strands

Short cut strands (according to ISO/DIS 13922).

Chopped strands mat

A mat formed of strands cut to a short length, randomly distributed, without intentional orientation, and held together by a binder (according to ISO/DIS 13922). 


A rotating cylinder onto which the glass filaments are wound during the forming stage. 

Continuous strand mat

A mat formed of uncut strands, held together by a binder (according to ISO/DIS 13922). 


Continuous full or partial heat cleaning conducted in a continuous oven. 


The number of warp and weft threads per centimeter, counted on a fabric free of tension. 

Coupling agent

A substance that promotes or establishes a stronger bond at the interface of the matrix resin and the reinforcement (according to ISO/DIS 13922). 


Operation that consists of winding the glass yarn around an electrical conductor, in one or more layers, to provide it with an insulating sheath (also known as wrapping).


A structure holding a predetermined number of packages, from which the yarns are pulled smoothly and uniformly for additional processing operations, such as warping, sectional warping, warping sizing, laid scrim and more.

Combustible matter content

The ratio of the mass of material removed on calcinations from a dried textile glass product to the mass of the dried product (according to ISO/DIS 13922). Also called loss on ignition (LOI).

Crowfoot weave

A broken-twill weave, 1-up and 3-down or 3-up and 1-down, with two ends to the right and two ends to the left, commonly referred to as four-harness satin or broken crow (according to ASTM D 579).

D - F



Glass composition with higher dielectric characteristics than E-glass, used in the manufacture of radomes, electromagnetic windows and high performance printed circuit boards.

Desized product

Product (yarn, fabric, etc.) from which the size has been removed, for example, by extraction with suitable solvents or by thermal treatment (according to ISO/DIS 13922).

Direct roving

A large and predetermined number of filaments obtained by winding directly from a bushing (according to ISO/DIS 13922).



A calcium alumino-borosilicate glass containing less than 1% of alkali oxide when calculated as Na2O.


Term used to describe warp yarns.


Operation that consists of threading warp yarns from the loom beam through the heddles of the harness shaft and then through the reed blade to achieve the desired design.



A planar structure composed of textile products.

Fabric construction

Number of yarns per centimeter length in the warp and weft directions, possibly extended to the weave pattern (according to ISO/DIS 13922).


A textile structure characterized by interlocking and consolidation of its constituent fibers, achieved by the interaction of a suitable combination of mechanical energy, chemical action, moisture and heat, but without the use of weaving, knitting, stitching, thermal bonding or adhesives (according to ASTM D 2475).


A generic term designating a unit of matter characterized by a high ratio of length to thickness or diameter (according to ISO/DIS 13922).


A single textile element of small diameter compared to its length; it can be continuous or discontinuous (according to ISO/DIS 13922).


Yarn running crosswise to the warp in a fabric (also known as fill, pick, weft).


A treatment applied to fabric to improve the adhesion with a resin matrix.


Protuberance of broken filaments on the surface of fabric or yarn (also known as fluff).

Fuzz ball

Accumulation of free broken filaments in fabric or yarn structure.

G - L


Greige fabric

Fabric that has received no finish (also known as loom state, untreated).


Heat cleaning

Thermal treatment conducted in a static oven to remove the organic materials applied to glass fabrics.


Inspection machine

A well-lighted device on which a roll of fabric is running slowly and continuously to permit an observer to identify and quantify the number of defects (also known as grading machine).


Kinky filling

Filling with protruding loops on the surface of a fabric.

Knitted scrim

Flat structures in which both warp and weft yarns are regularly, widely spaced and fixed by means of a warp knitting process.


Laid scrim

Textile structure in which the weft and warp yarns are linked together by an adhesive.

Laminated fabric

A multi-layer fabric, in which the successive layers are fixed by bonding or impregnation on one or more surfaces.

Linear density

The mass per unit length of the yarn, with or without size, expressed in the tex system ( (according to ISO/DIS 13922).

Loom beam

A large spool, on which the warp yarns are bound, that feeds the loom.

Loss on ignition (LOI)

Amount of organic material applied to glass filament consumed by ignition (according to ASTM D 123).Also called combustible matter content.

M - P



A flat structure made of strands, cut or uncut, oriented or not, held together in the form of a sheet (according to ISO/DIS 13922).

Mesh fabric

A flat fabric in which both warp and weft yarns are widely spaced and locked by means of the leno weaving process. 

Milled filaments

Filaments broken into very short lengths by processing through a size-reduction mill.



Needled mat

A mat whose elements are felted together in a needle loom, with or without a carrier (according to ISO/DIS 13922). 

No-twist roving (for over-end unwinding)

A roving in which intentional twist was placed during assembly, so that when pulled from a designated end of the package, the twist is removed (according to ISO/DIS 13922).

Non-woven fabric

A textile structure produced by bonding or interlocking of fibers or both, accomplished by mechanical, chemical, thermal or solvent means and combinations thereof (according to ASTM D1117).




Yarn in the form of units capable of being unwound and suitable for handling, storing, shipping and use (according to ISO/DIS 13922).

Plain weave

A fabric pattern in which each yarn of the filling passes alternately over and under a yarn of the warp and each yarn of the warp passes alternately over and under a yarn of the filling (according to ASTM D 4850).

Plied yarn

Yarn made from two or more single yarns, which have been combined in a second twisting operation.

R - S



Glass composition with higher mechanical performance than E-glass, used in the "leading-edge" sectors, including aircraft, space and defense, sport and leisure industries, transport and ballistic armors.


A collection of parallel strands (assembled roving) or parallel continuous filaments (direct roving) assembled without intentional twist (according to ISO/DIS 13922).




Woven or non-woven structure in which the yarns are regularly and widely spaced

Secondary sizing or wrap size

Chemicals applied to the warp yarn to improve strand integrity and abrasion resistance to withstand additional textile processing.

Section beam 

A large spool onto which yarns or strands pulled from a creel are wound.

Single yarn 

A continuous element, directly usable for textile operation, made with either:

•A given number of continuous filaments (one or several strands) held together with twist

•A number of discontinuous filaments, held together with twist (according to ISO/DIS 13922)


Mixture of chemical products applied to continuous or discontinuous filaments during their manufacture. A plastic size is a product designed to obtain a good bond between the surface of the fiber and the matrix resin. It generally contains ingredients that facilitate certain operations of conversion or application (winding, chopping, etc.). A textile size is a product designed to facilitate subsequent textile operations (twisting, folding, weaving, etc.).

 A textile plastic size is a product designed either to facilitate subsequent textile operations or to promote the bond between the surface of the fiber and the matrix resin (according to ISO/DIS 13922).


Operation in which the secondary size, also called warp size, is applied to yarns from several section beams. The sheets are then dried and wound on a beam to make up the loom beam.


A tubular structure with a collapsed width not exceeding 100 mm (according to ISO/DIS 13922). Also called tubing. 


A continuous assembly of slightly bonded discontinuous filaments in a practically parallel arrangement (according to ISO/DIS 13922).


A yarn made of two ends of yarn bound together pneumatically.

Spun roving

A fiberglass strand repeatedly doubled back on itself to form a roving, sometimes reinforced by one or more straight strands (according to ISO/DIS 13922).

Staple yarn 

Yarn spun from discontinuous filaments (according to ISO/DIS 13922). 


An assembly of simultaneously produced parallel continuous filaments, slightly bonded and without intentional twist (according to ISO/DIS 13922).

T - V



Small piece of yarn wound and fixed around the base of the bobbin before the start of the twisting process. It allows the splicing of two packages in order to make possible the continuous supply of textile processing.


A narrow fabric.


A non-woven fabric composed of chopped filaments used as a reinforcement material for flooring and roofing (also known as roofing mat).


A direct yarn numbering system that gives the linear density, as being the mass in grams per 1,000 meters of yarn length. 

Texturized product          

"In the texturizing process, the glass yarns or strands are overfed in a nozzle in which an air stream creates a turbulence that causes a disorganization of the structure and the formation of loops. 

The texturizing effect can be fixed by chemical means."


A large number of filaments gathered substantially without twist (according to ISO/DIS 13922).

Tubing (in textiles)          

A tubular structure with a collapsed width greater than 100 mm (according to ISO/DIS 13922). Also called sleeving. 


The Vetrotex registered trade name for voluminized and texturized products.

Twill weave        

A weave characterized by diagonal lines produced by a series of floats staggered in the warp direction, which are normally formed by the filling (a filling-faced twill) (according to ASTM D 4850).


Process that imparts to the strand from the cake a slight twist in order to improve the abrasion resistance and the strand integrity of yarns.

Type of weave  

Method of interlacing warp and weft to give a regular, repeating pattern of weaving, for example, plain, satin, twill, etc. (according to ISO/DIS 13922).



Unidirectional fabric       

A flat structure with a great number of yarns in one direction.



Voluminized product      

In the voluminized process, the glass yarns or strands are fed into a nozzle in which an air stream creates a turbulence, imparting bulk.

W - Z



Yarns lying in the lengthwise direction of the fabric (0° direction) (according to ISO/DIS 13922).  


Operation in which a predetermined number of parallel and equally tensioned yarns or ends are pulled from a creel and wound by a warper on a large spool, called a beam, to make up the section beam.

Weave pattern  

The way in which warp and weft threads cross each other. Web flat structure made with filament that is laid, with or without orientation, and held together by appropriate means (according to ISO/DIS 13922). 


Yarn running crosswise to the warp in a fabric (also known as fill, pick).


A machine with a rotating cylinder that draws glass into filaments and winds them into package form as a cake or roving.

Woven fabric

A reinforcement filament fabric made by interlacing at least two sets of threads perpendicular to each other or at some other specified angle, such interlacing being formed during weaving on a loom or weaving machine (according to ISO/DIS 13922).

Woven scrim

A flat structure in which both warp and weft yarns are widely spaced and woven according to a plain weave pattern.                           



A general term covering all specific types of textile structures, with or without twist, made of continuous or discontinuous filaments (according to ISO/DIS 13922).                          


ZeroTwist® products

Glass filament products are manufactured with no intentional twist.