Technical Textiles:

Technical Textiles:

A technical textile is a textile that has been developed to meet the exacting specified high-performance requirements of a particular end-use other than conventional clothing and furnishings. In many cases, specially developed technical yarns are employed to support and reinforce the fabric properties .

Technical Textiles

Markets for Technical Textiles:
According to Professor S. Anand of Bolton Institute, England, technical textiles account for approximately 21 per cent of all textiles. The main markets are: traditional industrial fabrics, for example, canvas, tents, etc. (43%); transportation and automotive (23%); leisure (12%); geotextiles (10%); medical textiles (10%); and protective apparel (2%). Two-thirds of automotive materials go into ‘interior trim’ for seat covers, roof and door liners, and carpets, where woven fabrics still dominate. Other uses include tyres, air bags and filters. Although non-woven and woven fabrics account for the majority of technical textiles, warp knitted and, to a lesser extent, weft knitted structures have captured some special end-use markets.These are particularly where certain properties such as drapability, mouldability, knitting to shape, open-work, extensibility, strength, lightness of weight and cost are at a premium and can be tailored to requirements.

End-uses for Technical Textiles:
Possible specific applications for technical textiles are as follows:

1. Geotextiles – Drainage, filter, and membrane material, road and tunnel reinforcement,erosion protection.
2. Tarpaulins, coverings – Air-inflated structures, tarpaulins, roof coverings, temperature-resistant sails, back-lit advertising signs.
3. Safety textiles – Heat and flame-resistant protective clothing for civil and military purposes, fluorescent safety clothing, inflatable life rafts, bullet-proof vests, helmets, sun protection blinds, radiation protection, parachutes, oil trap mats.(Bullet-proof vest fabric can be knitted on a Karl Mayer E 18 raschel machine with a magazine weft insertion and three guide bars. The front bar is threaded with 80 dtex polyester guide bars and laps 1–0/2–3. The other two bars ‘interweave’ with the front bar using the evasion technique 00/11/00/22 and 00/22/00/11 (Chapter 27).These, together with the weft insertion mechanism, are threaded with 840 dtex aramid.
4. Industrial Textiles – Filter fabrics, conveyor belts, adhesive tapes.
5. Medical Textiles – Plasters, tapes, gauze, artificial arteries, bandages, dialysisfilters, elastic net bandages, blankets and covers. (Small-diameter, single cylinder machines are ideal for weft knitting tubular stretch bandages from cotton yarn with inlaid elastic yarn .
6. Composites – Composites for buildings, aerospace, automobiles, boats.
7. Active Sportswear – Clothing and equipment.
8. Nets – Fabrics for construction, agriculture, for safety, weather and pest protection, blinds, fences, storage nets, sacks, fish nets .

Protective Textiles, Study on Bullet Proof Vest

A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor that helps absorb the impact from firearm-fired projectiles and shrapnel from explosions, and is worn on the torso. Soft vests are made from many layers of woven or laminated fibers and can be capable of protecting the wearer from small-caliber handgun and shotgun projectiles, and small fragments from explosives such as hand grenades.

Modern body armor may combine a ballistic vest with other items of protective clothing, such as a combat helmet. Vests intended for police and military use may also include ballistic shoulder and side protection armor components, and bomb disposal officers wear heavy armor and helmets with face visors and spine protection.

such type of vests use layers of very strong fiber to “catch” and deform a bullet, mushrooming it into a dish shape, and spreading its force over a larger portion of the vest fiber. The vest absorbs the energy from the deforming bullet, bringing it to a stop before it can completely penetrate the textile matrix. Some layers may be penetrated but as the bullet deforms, the energy is absorbed by a larger and larger fiber area.

While a vest can prevent bullet penetration, the vest and wearer still absorb the bullet’s energy. Even without penetration, modern pistol bullets contain enough energy to cause blunt force trauma under the impact point. Vest specifications will typically include both penetration resistance requirements and limits on the amount of impact energy that is delivered to the body.

Vests designed for bullets offer little protection against blows from sharp implements, such as knives, arrows or ice picks, or from bullets manufactured of non-deformable materials, e.g., those containing a steel core instead of lead. This is because the impact force of these objects stays concentrated in a relatively small area, allowing them to puncture the fiber layers of most bullet-resistant fabrics.

Textile vests may be augmented with metal (steel or titanium), ceramic or polyethylene plates that provide extra protection to vital areas. These hard armor plates have proven effective against all handgun bullets and a range of rifles. These upgraded ballistic vests have become standard in military use, as soft body armor vests are ineffective against military rifle rounds. Corrections officers and other law enforcement officers often wear vests which are designed specifically against bladed weapons and sharp objects. These vests may incorporate coated and laminated para-aramid textiles or metallic components.

Technical Textiles Glossary

Textiles are indispensable part of human life. They are used mainly to cover the human body for protection against all the adversities. Technological innovations have also made it possible for textile industry to offer technical solutions to the multiple end-users in the different industries.

Technical textiles are defined as textile materials and products used primarily for their technical performance and functional properties rather than their aesthetic or decorative characteristics. Other terms used for defining technical textiles include industrial textiles, functional textiles, performance textiles, engineering textiles, invisible textiles and hi-tech textiles.

An outstanding feature of the technical textile industry is the range and diversity of raw materials, processes, products and applications that it encompasses.

Technical textiles are used individually or as a component/part of another product. Technical textiles are used individually to satisfy specific functions such as fire retardant fabric for uniforms of firemen and coated fabric to be used as awnings. As a component or part of another product, they are used to enhance the strength, performance or other functional properties of that product as done by the tyre cord fabrics in tyres and interlining in shirt collars. They are also used as accessories in processes to manufacture other products like filter fabric in food industry or paper maker felt in paper mills.

Technical textiles have been slowly but steadily gaining ground due to one or more of the reasons such as: functional requirement, health & safety; cost effectiveness; durability; high strength; light weight; versatility; customization; user friendliness; eco friendliness; logistical convenience etc.

Unlike conventional textiles used traditionally for clothing or furnishing, technical textiles are used basically on account of their specific physical and functional properties and mostly by other user industries. Depending on the product characteristics, functional requirements and end-use applications the highly diversified range of technical textile products have been grouped into 12 sectors application wise:

1. Agrotech (Agriculture, horticulture and forestry)
2. Buildtech (building and construction)
3. Clothtech (technical components of shoes and clothing)
4. Geotech (geotextiles, civil engineering)
5. Hometech (components of furniture, household textiles and floor coverings)
6. Indutech (filtration, cleaning and other industrial usage)
7. Meditech (hygiene and medical)
8. Mobiltech (automobiles, shipping, railways and aerospace)
9. Oekotech (environmental protection)
10. Packtech (packaging)
11. Protech (personal and property protection)
12. Sporttech (sport and leisure

Ultrasonic Technology in Nonwoven and Textile Industry

Flexible technology for a flexible market:

Today’s textile and nonwoven market is so complex that fields of application, production techniques and technologies for further processing as well as the variety of new products are difficult to grasp, even for specialists.The variety of new composite materials of fleece, paper, films and fabric as well as the numerous possibilities in terms of combinations have one requirement in common: a safe and reliable process.

Ultrasonics is also the method of choice for these materials, for example for parting fabrics so that there is no thickening of the material along the cut edges.

No consumables such as glue, staples or sewing thread are needed. The fabric remains intact, because no external thermal energy is directed into the fleece. Position, shape and displacement of the welding points can even support the desired properties of the composite.

Textiles is thus a field where ultrasonic technology can prove its uniqueness.

The Functioning Principle of Ultrasonic Welding:

Low frequency mains voltage is transformed into high frequency electrical energy. A converter connected in line converts these electrical oscillations into mechanical vibrations. This is done using a piezoelectric transducer having an efficiency above 95 %.

The mechanical vibrations are transferred to a transformer element coupied to the converter, the so-called booster. This booster optimises the amplitude for the horn.

The horn is individually manufactured for each application and transfers the ultrasonic energy to the material to be processed. To build up a mechanical clamping force, a so-called anvil is required enabling the energy to effect melting on account of physical processes (internal and external absorption).

The Optimum Process for any Application:

Cycle-controlled process:

The actuator applies a defined pressure onto the anvil and hence onto the part to be welded between the two components. Usually, the ultrasonic irnpulse applied  simultaneously is time-controlled. Using the weld depth or the amount of energy applied as criteria for deactivation is also possible.

Main fields of application for cyclecontrolled welding:

• Overlapping welding of belts and tapes
• Linear welding of fabric and nonwoven
• Welding textile materials with thermoplastic contents
• Joining the end of a material strip to the start of a roll to prevent costintensive drawing in of material into the production equipment.

Seal and cut edges can also be manufactured to excellent quality. This only requires a special design of horn and anvil which is important for the following particular applications:

• Cut belt strips to length and/or punching
• Parting of edge binding for blankets
• Manufacturing buttonholes and eyes applying a certain structure to the rim in order to leave the impression of a sewn edge
• Parting colour ribbons in bureau machine industry

Continuous Process:

Two or more overlapping material strips are fed between horn and anvil which, if required, is rotating. Again, different systern combinations are possible:

Fixed Horn/Rotating Anvil:

This is the most commonly applied combination. Material strips (e. 9. fleece for use in agriculture) are joined at very high speeds using special profile wheels. Using profile wheels, sandwich structures can be generated. Combinations of different materials such as paper, films and textiles are particularly interesting applications. This combination can also be used for cutting processes. This usually involves cutting without sealing or with only slight edge sealling. The extension of the service life as well as the reduction of the cutting force and hence an increased cutting speed are strong arguments for the application of ultrasonic technology. Non-thermoplastic materials can also be cut. In this case ultrasonic energy supports breaking of the materials. Maximum precision is of course a prerequisite in such applications.

Rotating Horn/Rotating Anvil:

In this combination horn and anvil serve both to weld and to transport the welded product. In most cases both horn and anvil are driven synchronously. As in this system only a limited amplitude can be generated. This method is usually used for thin materials having a low mass per unit area.

Fixed HornlFixed Anvil:

This combination is usually used for cutting/ parting applications with simultancous sealing. However, it can also be used for continuous welding of paper, films, or textiles.