**5. Engineered fabrics**

Engineered fabrics are textile materials manufactured primarily for technical and functional performances. Most of the engineered fabrics are manufactured by assembly of fibers, yarns and/or strips of material which have a very high surface area in comparison to their thickness and have sufficient mechanical strength. Engineered fabrics are commonly manufactured by weaving, knitting, felting, lace making, nonwoven processes, net making and tufting or a combination of these processes. Most of the engineered fabrics are two dimensional structures but recently three-dimensional structures have become very popular structure in this segment. The knitted structure consist one set of thread, woven consist two set of threads in the form of warp and weft but three-dimensional structure consist three set of threads: warp, weft and stuffer thread.

warps and two weft act as a unit in plain weave). The unit of lifting threads can be increased

Introductory Chapter: Engineered Fabrics http://dx.doi.org/10.5772/intechopen.82717 7

Some typical matt weaves, like a 4/2 matt, are produced to obtain special engineered effects.

Plain weave can be modified in another way in which either the ends or picks keeps more with higher crimp is called rib structure. If the number of ends is more than picks per unit length with high warp crimp, it is called as warp rib and vice versa for weft rib fabrics [28].

Almost all two-dimensional woven structures have been developed from plain weave fabrics in which warp and weft yarns are interlaced at 90° or at nearly 90°. The triaxial fabrics are the only exception, where two sets of warp yarns are generally inserted at 60° to the weft. In case of tetra-axial fabrics, four sets of yarns are inserted at 45° to each other. Triaxial fabrics are manufacturing on commercial machines. The first triaxial weaving machines were developed by the Barber Colman Co. and further developed by Howa Machinery Ltd., Japan. Triaxial fabrics can be defined as set of threads where the three sets of threads form a multitude of equilateral triangles in which two sets of warp yarn are interlaced at 60° with each other and with the weft. The tearing and bursting strength of triaxial fabrics is remarkable higher than conventional fabrics. The shear rigidity of triaxial fabrics remains superior due to locked intersection points. Triaxial woven engineered fabrics have found a wide range of technical applications in, balloon fabrics, pressure receptacles, sailcloths, tyre fabrics and laminated structures [29].

Three-dimensional woven engineered fabrics are produced to enhance the strength, thick-

The performance of 3D woven fabrics can be engineered by making some alteration in weave used, the thread spacing, raw materials structure (filament or staple), linear density (or count) and twist factors of the warp and weft yarns. There are countless possibilities in 3D woven

Engineered fabrics manufacturing processes: the essential operations in the weaving of a

• Shedding, i.e. the separation of the warp threads into two (or more) sheets according to a

• Beating-up, i.e. forcing the pick, which has been inserted into the shed, up to the fell of the

Secondary motions are incorporated to make the provision for the supply of warp and weft warp yarns and for the cloth. The warp yarn is usually supplied from warp beam(s) and the

cloth (line where the cloth terminates after the previous pick has been inserted).

ness, extensibility, porosity and durability in woven engineered fabrics.

engineered fabrics to manufacture engineered fabrics of desired properties [5].

to 3 or 4 to create 3/3 or 4/4 matt weave structures.

*5.1.3. Three-dimensional woven engineered fabrics*

pattern to allow for weft insertion

• Weft insertion (picking)

*5.1.2. Triaxial weaves*

cloth are:

#### **5.1. Weave structures**

The two dimension engineered fabrics consists various weaves in which plain and leno weaves are widely used. There are some others weaves which can be proved functionality in engineered fabrics. All threads do not follow the straight path in woven structures and consist a crimp [24].

#### *5.1.1. Plain weave and derivatives*

The simplest weave to manufacture engineered fabrics is plain weave which is produced by alternatively lifting and lowering one warp thread across one weft thread. The performance of engineered fabrics has plain weave will depend type of fiber used: either staple or filament, type of yarn: flat, textured and twisted, yarn linear density and fabric set. The bending rigidity of engineered fabrics depends on the stiffness of the raw materials used and by the twist factor of the yarn and thread density in woven fabric [25]. Amount of twist in constituent yarns of engineered fabrics is used to impart specific features like extensibility, surface roughness and texture, etc. By changing the areal density (fabric grams per square meter, GSM) and cover factor affect the abrasion resistance, dimensional stability, filtration potential, porosity, stiffness, strength and thickness of engineered fabrics can be altered [26]. Square sett plain woven fabrics that are fabrics have nearly the constant number of ends and picks per unit space and warp and weft yarns of the same linear densities are produced with similar cover factors. Light weight plain woven fabrics with lower areal density and low cover factor with open weave construction are used as bandages and cheese cloths while highly open cloths are used in geotextile stabilization fabrics and heavy closely woven fabrics include cotton awnings.

Plain weave can be modified in the form of Rib and Matt weave. These weaves are produced when two or more than two adjoining warp or weft threads are considered as one unit and lifts or downs simultaneously. These weaves gives a higher cover factor, without jamming the weave structure [27].

Simple matt (or hopsack) woven fabrics offer a similar texture to plain woven fabric. The simplest matt weave is a 2/2 matt where two warp ends are lifted over two picks (unit of two warps and two weft act as a unit in plain weave). The unit of lifting threads can be increased to 3 or 4 to create 3/3 or 4/4 matt weave structures.

Some typical matt weaves, like a 4/2 matt, are produced to obtain special engineered effects.

Plain weave can be modified in another way in which either the ends or picks keeps more with higher crimp is called rib structure. If the number of ends is more than picks per unit length with high warp crimp, it is called as warp rib and vice versa for weft rib fabrics [28].

#### *5.1.2. Triaxial weaves*

**5. Engineered fabrics**

6 Engineered Fabrics

and stuffer thread.

a crimp [24].

**5.1. Weave structures**

weave structure [27].

*5.1.1. Plain weave and derivatives*

Engineered fabrics are textile materials manufactured primarily for technical and functional performances. Most of the engineered fabrics are manufactured by assembly of fibers, yarns and/or strips of material which have a very high surface area in comparison to their thickness and have sufficient mechanical strength. Engineered fabrics are commonly manufactured by weaving, knitting, felting, lace making, nonwoven processes, net making and tufting or a combination of these processes. Most of the engineered fabrics are two dimensional structures but recently three-dimensional structures have become very popular structure in this segment. The knitted structure consist one set of thread, woven consist two set of threads in the form of warp and weft but three-dimensional structure consist three set of threads: warp, weft

The two dimension engineered fabrics consists various weaves in which plain and leno weaves are widely used. There are some others weaves which can be proved functionality in engineered fabrics. All threads do not follow the straight path in woven structures and consist

The simplest weave to manufacture engineered fabrics is plain weave which is produced by alternatively lifting and lowering one warp thread across one weft thread. The performance of engineered fabrics has plain weave will depend type of fiber used: either staple or filament, type of yarn: flat, textured and twisted, yarn linear density and fabric set. The bending rigidity of engineered fabrics depends on the stiffness of the raw materials used and by the twist factor of the yarn and thread density in woven fabric [25]. Amount of twist in constituent yarns of engineered fabrics is used to impart specific features like extensibility, surface roughness and texture, etc. By changing the areal density (fabric grams per square meter, GSM) and cover factor affect the abrasion resistance, dimensional stability, filtration potential, porosity, stiffness, strength and thickness of engineered fabrics can be altered [26]. Square sett plain woven fabrics that are fabrics have nearly the constant number of ends and picks per unit space and warp and weft yarns of the same linear densities are produced with similar cover factors. Light weight plain woven fabrics with lower areal density and low cover factor with open weave construction are used as bandages and cheese cloths while highly open cloths are used in geotextile stabilization fabrics and heavy closely woven fabrics include cotton awnings.

Plain weave can be modified in the form of Rib and Matt weave. These weaves are produced when two or more than two adjoining warp or weft threads are considered as one unit and lifts or downs simultaneously. These weaves gives a higher cover factor, without jamming the

Simple matt (or hopsack) woven fabrics offer a similar texture to plain woven fabric. The simplest matt weave is a 2/2 matt where two warp ends are lifted over two picks (unit of two Almost all two-dimensional woven structures have been developed from plain weave fabrics in which warp and weft yarns are interlaced at 90° or at nearly 90°. The triaxial fabrics are the only exception, where two sets of warp yarns are generally inserted at 60° to the weft. In case of tetra-axial fabrics, four sets of yarns are inserted at 45° to each other. Triaxial fabrics are manufacturing on commercial machines. The first triaxial weaving machines were developed by the Barber Colman Co. and further developed by Howa Machinery Ltd., Japan. Triaxial fabrics can be defined as set of threads where the three sets of threads form a multitude of equilateral triangles in which two sets of warp yarn are interlaced at 60° with each other and with the weft. The tearing and bursting strength of triaxial fabrics is remarkable higher than conventional fabrics. The shear rigidity of triaxial fabrics remains superior due to locked intersection points. Triaxial woven engineered fabrics have found a wide range of technical applications in, balloon fabrics, pressure receptacles, sailcloths, tyre fabrics and laminated structures [29].

#### *5.1.3. Three-dimensional woven engineered fabrics*

Three-dimensional woven engineered fabrics are produced to enhance the strength, thickness, extensibility, porosity and durability in woven engineered fabrics.

The performance of 3D woven fabrics can be engineered by making some alteration in weave used, the thread spacing, raw materials structure (filament or staple), linear density (or count) and twist factors of the warp and weft yarns. There are countless possibilities in 3D woven engineered fabrics to manufacture engineered fabrics of desired properties [5].

Engineered fabrics manufacturing processes: the essential operations in the weaving of a cloth are:


Secondary motions are incorporated to make the provision for the supply of warp and weft warp yarns and for the cloth. The warp yarn is usually supplied from warp beam(s) and the weft yarn from the pirn on shuttle looms only or cones on shuttles looms. Most of the single phase weaving machines uses same kind of motions and an almost horizontal warp sheet between the back rest and the front rest. Such kind of system is utilized in common shuttle looms, rapier looms, projectile looms, air jet looms and water jet looms [30].

converted to engineered nonwoven fabric by opting anyone way of either bonding or entanglement. The strength of bond in parallel laid nonwoven remains less than individual fiber strength. The parallel laying process suits to manufacture narrow tapes and medical textiles while cross laying suits to filter and wipe fabrics. However randomized doffer cards neutralize the situation up to major extent by distributing the fibers randomly together with 'scrambling rollers'. Both parallel laid and cross laid laying shows anisotropic behavior, however by combining both parallel laying and cross laying isotropic nonwoven structures are engineered.

Introductory Chapter: Engineered Fabrics http://dx.doi.org/10.5772/intechopen.82717 9

The final width of nonwoven engineered structure is a challenge and it can be overcome by

In order to result cross laying of webs to form batt, the cards are kept at right angles to the main conveyor lattice M and the card web is moved backwards and forwards across the main

The speed of main conveyor lattice is kept slow to accommodate many layers of card web in desired order. The cross laying systems suffers with two major problems; first, this system prone to form heavier batt at the edge due to overlapping. This issue can be solved by moving the of direction of batt at the edge of lattice. The second is to match the input speed of cross laying with card web speed. Generally input speed remains less and card web speed must

This technique of batt formation is influenced by paper making industry. The fibers are dispersed into water and water content is kept sufficient to prevent fiber aggregation. This system promotes the blending of fibers and laying them successfully. Wood pulps can also be blended with fibers to form the batt. This system is suitable to the batt of wooden pulp and fibers used in sanitary napkin manufacturing. The wet-laid batt is used in some other disposable engineered products like drapes, gowns, sometimes as sheets, as one-use filters, and as

This technique of batt formation offers shortest route. This includes extrusion of the filaments from extruder, drawing the filaments and laying them in the form of batt. At the same time bonding also takes place which makes this process very economic from polymer to fabric manufacturing cost point of view. Initially, this process was developed for large scale production but at present small size machines are available to cater the need of small scale manufacturers. Initially polyester and polypropylene fibers were spun-laid but presently polyamide and polyethylene fibers can also be processed on this system. The microfiber technology also integrated with this system which enhanced the versatility to produce finer, softer and better filtration engineered fabric structures. The process starts from feeding of polymer chips into extruder which feeds the molten mass of polymer to a metering pump and then to a group of

combining various laying techniques [32].

**7.2. Cross laying**

**7.3. Wet laying**

**7.4. Spun laying**

moving conveyor lattice.

reduce to match with input speed.

coverstock in disposable nappies [33].
