INTRODUCTION TO TEXTILES
TEXTILE FIBRES
A fibre is a solid and quite flexible material, with a little cross section and a high relation about length – width.
The fibres classify in 3 big groups: natural and man – made that clasiffies in artificial and synthetics.
NATURAL FIBRES
These are extracted directly from nature, through physical or mechanic procedures. They classify in 3 groups:
Vegetable - (cellulose base): cotton, linen, ramie, hemp, jute,etc
Animal - (protein base): wool, silk, etc.
Mineral- asbestos (in disuse), glass (also considered synthetic fibre), etc.
MAN – MADE FIBRES
ARTIFICIAL
These have its origin on naturals (natural polymer) and are chemically modified by men.
Most common are:
Acetate
Viscose
They are obtained through the cellulose mainly extracted from the bark of trees. Later, they are chemically modified until to convert them in a textile fibre possible to be yarn.
SYNTHETIC FIBRES
These are obtained from synthetic polymers by product of petroleum.
Most common are:
Polyester (Avora and Trevira are fire retardants derivated from this)
Acrylic
Polypropylene
Nylon
YARN
Large and fine cord that forms by putting on parallel, stretching and twisting any fibre or textile fibres.
In essence we could divide yarns in 2 big groups:
SPUN YARN (cotton, wool, polyester, acrylic, etc.)
CONTINOUS FILAMENT YARN (polyester, polypropylene, silk, etc.)
In this 2 groups there are various yarn types as:
single, twisted, flamé, knotted, corkscrew, chenille, high volume, texturized, compacted, taslanized, etc.
Some of the previous types of yarns are made from a conventional or single one. With others, there has to be applied a kind of “finish” or some extra yarns through a machine that modifies the conventional production of the yarn, this could be the case for example: chenille.
Any yarn can be constructed by one or more fibre blends. The blend of fibres for the production of a yarn is called close blend, each blends are made mainly by polyester / cotton. These are of a great use and acceptance in the manufacture of fabrics for decoration.
Any yarn can be made of one or more ends, this means that for one or more cords joined together and twisted between them, they can form a yarn.
Fabrics with a process of manufactured yarn, either conventional or fancy, in mostly all cases with the addition of dyes to weave them subsequently , are called as pre – dyed fabrics with pre- dyed yarns. It is possible too, to print the yarn, although is is not very common.
FABRIC
A fabric is an estructural lamina as a result of joining fibres of diverse origin by knitting, weaving or non weaving. There are several types of fabrics, depending on their construction, the way they are woven, here we could divide them in 3:
knitted fabrics
warp and weft fabrics
non woven fabrics
KNITTED FABRICS
This consists of the interweaving of a yarn by itself.
Examples:
underwear, socks, t – shirts, jerseys, etc.
WARP & WEFT FABRICS
Consists by 2 elements:
Warp: group or groups of vertical yarns in regard to the weaver and perpendicular to the weft.
Weft: group or groups of horizontal yarns in regard to the weaver and perpendicular to the warp.
Examples:
Denim, upholstery, sheets, towels, etc.
NON WOVEN
Consists of gathering textile fibres with adhesives and mechanic methods.
Examples:
diapers, surgical clothes, kitchen napkins, suede, etc.
WARP & WEFT WEAVING
It is formed by 2 clearly different elements.
The weaving process starts making the warp in a machine called warper, rolling the ends for the number of meters needed. Then, at the end of the process they are put on a beam. After that, the beam is transfered to the back of the loom and the warp ends are knotted with the yarn tails of the previous beam. This way the yarns pass through the eyes of the mesh and through the comb´s gap that corresponds.
Then, the weft will pass into the “tunnel” called shed that forms the warp, with the loom system (rigid or flexible rapier insertion, shuttle, air- jet, water – jet, projectile, etc.) and incorporates every pick to the weave through the beat of the reed and so on to make the fabric.
DOBBY WEAVING
Warp and weft weaving, where the warp is moved in groups of yarns inserted in the meshes. These are grouped in structures called shafts or healds moved by dobby shafts.
JACQUARD WEAVING
Warp and weft weaving too, but in this case, the yarns are moved by a machine called Jacquard that allows an individual movement of every thread, altough this is limited, with this kind of weave it can be made fabrics with very complex designs that with a dobby weaving would not be possible to do.
SPECIAL WEAVING
Weaving that continues from warp and weft system, but on their manufacture some elements are added. The most common case is the velvet, which uses a third warp that later will be shaved to obtain the characteristic feeling. Also the “ blackout” combines in general two or three layers of fabric previously woven and with a sizing of acrylic resin foamed. This layers are “stucked” between them as a sandwich. The goal is to avoid the light to pass through the fabric, it can have flame retardant, it can be inherent to the fibre, added by immersion or shaver.
WEAVE
The manner in which the yarns or threads interlace or structure themselves is called weave. The main weaves are:
plain, twill and satin.
Eventhough there´s a great variety of weaves all have as base the three basics.
The yarns combination, the fibres, the rates, the types and colors of the warp and weft, the weaves that are being used, the design as the finishes; all of this will give us the fabric we want to make.
WDTHS
A fabric width can vary because of the loom where is going to be woven and the client needs. Mainly in decoration it is used a 1.40 m (55”). This is used for upholstery most of the time. The 2.80 m (110”), is very useful for curtains, bedding (bedspreads, sheets, etc.) On printing, the print bases are of 1.50 m width.
FINISHING
There are several textile finishings. A finishing is all process that gives an added value to the previously woven fabric. It can be a value for esthetic, resistance, protection, etc.
Most common finishing in decoration are:
BOILING OUT
Process that eliminates the impurities that the fabric has got during the process of its manufacture, since the spinning to the weaving. With this process, the fabric can be commercialized or another process like printing can be applied.
BLEACHING
It is similar to the boiling out finishing, but in this case the fabric is dyed with white.
DYE IN THE PIECE
Process where color is applied to the fabric. The machines used fot this are the Jets and the Jiggers, these work with the heat, pressure, dye formulation, softener, etc. which is needed.
It is very important to think about the different fibres, because they have each dyeing affinity. The correct use allows to obtain “extra” results through the process of dyeing in the piece.
PRINTING
Process of capturing a print base to the fabric and it can be any design, but it´s limited by the printing technique. There are 3 industrial techniques:
Woodblock Printing: process where the color is added to the fabric through serigraphy or screen printing.
Transfer printing: process where the color is added by sublimation of the pigments which were previously added on paper. The pigments transfered by heat and pressure effects that the printing machine does over the paper on the fabric.
Roller or cylinder printing: process where the rollers with previously engraved design zones (as many as colors to print) let the heat passes through. This way the design is added on the print base that runs under the rollers.
BACKING
Textiles finishing that gives the fabric a sizing of acrylic resin. It is applied on the back of the fabric with the aim of giving stiffness and consistency, due to manipulate better the textile on the process of making up of the ultimate product and have less slipagge of the fabric threads.
FIREPROOF BACKING
It is similar to the previous, but adding a product that can postpone by a few moments the flame and in rare cases extinguish it when the fabric is put on fire.
FLAME RETARDANT
In this finishing the fabric is placed by immersion on a solution that adds some products that retard the combustion process of the fabric.
STAIN REPELLENT OR STAIN RESISTANCE
Finishing that gives the textile an invisible coat whith thi,s stains cannot be absorbed.
DEVORE
Process where quimical substances destroy some fibre or fibres, meanwhile another fibre or fibres
aren´t damaged. This finishing gives the fabric some holes or parts without some textile material.
IRONING
The fabric passes through some cylinders at certain temperature. The function here is to eliminate possible wrinkles, also to give the fabric a better “draping”and shine.