Classification and Applications of Technical Textiles

Classification and Applications of Technical Textiles

 Electronic textile
Technical Textiles:
Technical textiles are reported to be the fastest growing sector of the textile industrial sector. 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.

It is considered that 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%).
Classification and Applications of Technical Textiles:

Agriculture, Horticulture and Fishing:
Textiles have always been used extensively in the course of food production, most notably by the fishing industry in the form of nets, ropes and lines but also by agriculture and horticulture for a variety of covering, protection and containment applications. Although future volume growth rates appear to be relatively modest, this is partly due to the replacement of heavier weight traditional textiles, including jute and sisal sacking and twine, by lighter, longer lasting synthetic substitutes, especially polypropylene. Lightweight spun bonded fleeces are now used for shading, thermal insulation and weed suppression. Heavier nonwoven, knitted and woven constructions are employed for wind and hail protection. Fibrillated and extruded nets are replacing traditional baler twine for wrapping modern circular bales. Capillary nonwoven matting is used in horticulture to distribute moisture to growing plants. The bulk storage and transport of fertilizer and agricultural products is increasingly undertaken using woven polypropylene FIBCs (flexible intermediate bulk containers – big bags) in place of jute, paper or plastic sacks. At sea, fish farming is a growing industry which uses specialized netting and other textile products. High performance fibres such as HMPE (e.g. Dyneema and Spectra) are finding their way into the fishing industry for the manufacture of lightweight, ultra-strong lines and nets.

Construction-Building and Roofing:
Textiles are employed in many ways in the construction of buildings, both permanent and temporary, dams, bridges, tunnels and roads. A closely related but distinct area of use is in geotextiles by the civil engineering sector. Temporary structures such as tents, marquees and awnings are some of the most obvious and visible applications of textiles where these used to be exclusively made from proofed heavy cotton, a variety of lighter, stronger, rot-, sunlight- and weatherproof (also often fireproof) synthetic materials are now increasingly required. Nonwoven glass and polyester fabrics are already widely used in roofing applications while other textiles are used as breathable membranes to prevent moisture penetration of walls. Fibres and textiles also have a major role to play in building and equipment insulation. Glass fibres are almost universally used in place of asbestos now. Double wall spacer fabrics can be filled with suitable materials to provide sound and thermal insulation or serve as lightweight cores for composite materials. Composites generally have a bright future in building and construction. Existing applications of glass-reinforced materials include wall panels, septic tanks and sanitary fittings. Glass, polypropylene and acrylic fibres and textiles are all used to prevent cracking of concrete, plaster and other building materials. More innovative use is now being made of glass in bridge construction.  

Home Textiles:
By far the largest area of use for other textiles as defined above, that is other than fabrics, nonwovens and composite reinforcements, over 35% of the total weight of fibres and textiles in that category, lies in the field of household textiles and furnishing and especially in the use of loose fibres in wadding and fiberfill applications. Hollow fibres with excellent insulating properties are widely used in bedding and sleeping bags. Other types of fibre are increasingly being used to replace foams in furniture because of concern over the fire and health hazards posed by such materials.

Woven fabrics are still used to a significant extent as carpet and furniture backings and in some smaller, more specialized areas such as curtain header tapes. However, nonwovens such as spun bonded have made significant inroads into these larger markets while various dry laid and hydro-entangled products are now widely used in household cleaning applications in place of traditional mops and dusters.  

Medical and Hygiene Textiles:
The largest use of textiles is for hygiene applications such as wipes, babies’ diapers (nappies) and adult sanitary and incontinence products. Nonwovens dominate these applications which account for over 23% of all nonwoven use, the largest proportion of any of the 12 major markets for technical textiles. The other side of the medical and hygiene market is a rather smaller but higher value market for medical and surgical products such as operating gowns and drapes, sterilization packs, dressings, sutures and orthopaedic pads. At the highest value end of this segment are relatively tiny volumes of extremely sophisticated textiles for uses such as artificial ligaments, veins and arteries, skin replacement, hollow fibres for dialysis machines and so on.

Geotextiles in Civil Engineering:
The economic and environmental advantages of using textiles to reinforce, stabilise, separate, drain and filter are already well proven. Geotextiles allow the building of railway and road cuttings and embankments with steeper sides, reducing the land required and disturbance to the local environment. Revegetation of these embankments or of the banks of rivers and waterways can also be promoted using appropriate materials.

Transportation Textiles:
Transport applications (cars, Lorries, buses, trains, ships and aerospace) represent the largest single end-use area for technical textiles, accounting for some 20% of the total. Products range from carpeting and seating (regarded as technical rather than furnishing textiles because of the very stringent performance characteristics which they must fulfil), through tyre, belt and hose reinforcement, safety belts and airbags, to composite reinforcements for automotive bodies, civil and military aircraft bodies, wings and engine components, and many other uses.  

Packaging and Containment:
Important uses of textiles include the manufacturing of bags and sacks, traditionally. An even faster growing segment of the packaging market uses lighter weight nonwovens and knitted structures for a variety of wrapping and protection applications, especially in the food industry. Tea and coffee bags use wet-laid nonwovens. Meats, vegetables and fruits are now frequently packed with a nonwovens insert to absorb liquids. Other fruits and vegetable products are supplied in knitted net packaging from cotton, flax and jute but increasingly from polypropylene. Strong, lightweight spun bonded and equivalent nonwoven paper-like materials are particularly useful for courier envelopes while adhesive tapes, often reinforced with fibres, yarns and fabrics, are increasingly used in place of traditional twine. Woven strapping are less dangerous to cut than the metal bands and wires traditionally used with densely packed bales.  

Protective and Safety Clothing and Textiles:
Textiles for protective clothing and other related applications are another important growth area which has attracted attention and interest somewhat out of proportion to the size and value of the existing market. The variety of protective functions that needs to be provided by different textile products is considerable and diverse. It includes protection against cuts, abrasion, ballistic and other types of severe impact including stab wounds and explosions, fire and extreme heat, hazardous dust and particles, nuclear, biological and chemical hazards, high voltages and static electricity, foul weather, extreme cold and poor visibility.  

Sports Textiles :
Applications of sports textile are diverse and range from artificial turf used in sports surfaces through to advanced carbon fibre composites for racquet frames, fishing rods, golf clubs and cycle frames. Other highly visible uses are balloon fabrics, parachute and paraglider fabrics and sailcloth.  

Ecological Protection Textiles:
The final category of technical textile markets, as defined by Techtextile, is technical textiles for protection of the environment and ecology. This is not a well defined segment yet, although it overlaps with several other areas, including industrial textiles (filtration media), geotextiles (erosion protection and sealing of toxic waste) and agricultural textiles (e.g. minimizing water loss from the land and reducing the need for use of herbicides by providing mulch to plants). 

Introduction of Acrylic Fibers | Properties of Acrylic Fiber | Production Process of Acrylic Fiber | Uses of Acrylic Fiber

Introduction of Acrylic Fibers | Properties of Acrylic Fiber | Production Process of Acrylic Fiber | Uses of Acrylic Fiber

A manufactured fiber in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85% by weight of acrylonitrile units [-CH2-CH(CN)-] (FTC definition). Acrylic fibers are produced by two basic methods of spinning (extrusion), dry and wet. In the dry spinning method, material to be spun is dissolved is a solvent. After extrusion through the spinneret, the solvent is evaporated, producing continuous filaments which later may be cut into staple, if desired. In wet spinning, the spinning solution is extruded into a
liquid coagulating bath to form filaments, which are drawn, dried, and processed.

Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) with an average molecular weight of ~100,000, about 1900 monomer units. To be called acrylic in the U.S, the polymer must contain at least 85% acrylonitrile monomer. Typical comonomers are vinyl acetate or methyl acrylate. The Dupont Corporation created the first acrylic fibers in 1941 and trademarked them under the name “Orlon”.

Raw Material 
Acrilonitrile is the main main raw material for the manufacture of acrylic fibres. It is made by different methods. In one commercial method, hydrogen cyanide is treated with acetylene:
1st Method

Acetylene + Hydrogen cyanide —> Acrilonitrile

2nd Method
Ethylene—Air Oxidation—> Ethylene oxide + HCN—> Ethylene cyanahydrin—Dehydration at 300 deg C (catalyst)—> Acrylonitrile

Production Process of Acrylic Fiber
The acrylic process is a “one step technology”, with the following main characteristics:

1. polymerization in solution
2. direct feeding of the dope to spinning
3. wet spinning
4. DMF as solvent for both polymerization and spinning

Production Process of Acrylic Fiber

In a continuous polymerisation process, 95% acrylonitrile and 6% methyl acrylate (400 parts) 0.25% aqueous solution of K2S2O8(600 parts), 0.50 % Na2S2O5 solution ( 600 Parts) and 2N sulphuric acid (2.5 Parts) are fed into the reaction vessel at 52 deg C under nitrogen atmosphere giving a slurry with 67% polymer. The slurry is continuously withdrawn, filtered and washed till it is free from salts and dried.

Acrilonitrile is dry spun. The material is dissolved in dimethyl formamide, the solution contains 10-20 polymers. It is heated and extruded into a heated spinning cell. A heated evaporating medium such as air, nitrogen or steam moves counter current to the travel of filaments and removes the solvent to take it to a recovery unit. The filaments are hot stretched at 100 to 250 C depending on the time of contact in the hot zone, to several times their original length.

Properties of Acrylic Fibers

1. Acrylic has a warm and dry hand like wool. Its density is 1.17 g/cc as compared to 1.32 g/cc of wool. It is about 30% bulkier than wool. It has about 20% greater insulating power than wool.

2. Acrylic has a moisture regain of 1.5-2% at 65% RH and 70 deg F.

3. It has a tenacity of 5 gpd in dry state and 4-8 gpd in wet state.

4. Breaking elongation is 15% ( both states)

5. It has a elastic recovery of 85% after 4% extension when the load is released immediately.

6. It has a good thermal stability. When exposed to temperatures above 175 deg C for prolonged periods some discolouration takes place.

7. Acrylic shrinks by about 1.5% when treated with boiling water for 30 min. 

8. It has a good resistance to mineral acids. The resistance to weak alkalies is fairly good, while hot strong alkalies rapidly attack acrylic.

9. Moths, Mildew and insects do not attack Acrylic.

10. It has an outstanding stability towards commonly bleaching agents.

Uses of Acrylic Fiber

1. Knit Jersey, Sweater, blankets

2. Wrinkle resistant fabrics.

3. Pile and Fleece fabrics

4. Carpets and rugs.

Precaution of Acrylic Fiber 

• Wash delicate items by hand in warm water. Static electricity may be reduced by using a fabric softener in every third or fourth washing. Gently squeeze out water, smooth or shake out garment and let dry on a non-rust hanger. (Sweaters, however, should be dried flat.) 
• When machine washing, use warm water and add a fabric softener during the final rinse cycle. 
• Machine dry at a low temperature setting. Remove garments from dryer as soon as tumbling cycle is completed. 
• If ironing is required, use a moderately warm iron. (For specific instructions, refer to garment’s sewn-in care label.)

Application of Dyes According to Fiber Characteristics | Names of Different Dyes and Their Application

Application of Dyes According to Fiber Characteristics | Names of Different Dyes and Their Application

There are different types of dyes for dyeing textile goods. These dyes have different nature in fiber. It depends on fiber characteristics. Application of dyes in different fibers are given below:

Application of Dyes

Name of Dyes	Application
Acid dye	Man made fiber (Nylon), Natural fiber (Silk, Wool)
Direct Dye	Man made fiber (Viscose), Natural fiber (Cotton)
Vat dye	Man made fiber (Viscose), Natural fiber (Cotton, Silk, Wool)
Disperse dye	Nylon, Polyester, Acrylic, Tri-acetate, Di-acetate
Basic dye	Jute, Acrylic
Reactive dye	Cotton, Wool, Silk, Viscose, Nylon
Sulfur dye	Cotton, Viscose
Mordant dye	Cotton, Wool, Silk
Pigment	Cotton, Man made fiber
Mineral	Cotton, Wool, Silk
Azoic dye	Cotton, Viscose
Aniline Black	Cotton
Rapid and Rapidson dye	Cotton
Onium dye	Cotton, Jute

Different Types of Yarn Spinning System | Open-end Spinning | Ring Spinning, Rotor Spinning, Wet Spinning, Dry Spinning, Air-jet Spinning, Centrifugal Spinning, Flyer Spinning, Melt Spinning, Reaction Spinning, Flash Spinning, Draw-Spinning, Dispersion Spinning, Friction Spinning, Break Spinning

Different Types of Yarn Spinning System | Open-end Spinning | Ring Spinning, Rotor Spinning, Wet Spinning, Dry Spinning, Air-jet Spinning, Centrifugal Spinning, Flyer Spinning, Melt Spinning, Reaction Spinning, Flash Spinning, Draw-Spinning, Dispersion Spinning, Friction Spinning, Break Spinning

Spinning:

The present participle of the verb ‘to spin’ used verbally, adjectivally, or as a noun, meaning process or the processes used in the production of yarns or filaments. 

The term may apply to: 
(i) The drafting and, where appropriate, the insertion of twist in natural or staple man-made fibres to form a yarn; 
(ii) The extrusion of filaments by spiders or silkworms; or 
(iii) The production of filaments from glass, metals, fibre-forming polymers or ceramics.

 

Ring spinning

In the spinning of man-made filaments, fibre-forming substances in the plastic or molten state, or in solution, are forced through the holes of a spinneret or die at a controlled rate. There are five general methods of spinning man-made filaments i.e. dispersion spinning, dry spinning, melt spinning, reaction spinning, and wet spinning, but combinations of these methods may be used. 

In the bast and leaf-fiber industries, the terms ‘wet spinning’ and ‘dry spinning’ refer to the spinning of fibres into yarns in the wet state and in the dry state respectively. 

Open-end Spinning;

Break Spinning: 
A spinning system in which sliver feed stock is highly drafted, ideally to individual fibre state, and thus creates an open end or break in the fibre flow. The fibres are subsequently assembled on the end of a rotating yarn and twisted in. Various techniques are available for collecting and twisting the fibres into a yarn, the most noteworthy being rotor spinning and friction spinning. 

Rotor Spinning: 
A method of open-end spinning which uses a rotor (a high-speed centrifuge) to collect individual fibres into a yarn is known as Rotor spinning. The fibers on entering a rapidly rotating rotor are distributed around its circumference and temporarily held there by centrifugal force. The yarn is withdrawn from the rotor wall and, because of the rotation, twist is generated. 

Friction Spinning: 
A method of open-end spinning which uses the external surface of two rotating rollers to collect and twist individual fibres into a yarn is known as Friction spinning. At least one of the rollers is perforated so that air can be drawn through its surface to facilitate fibre collection. The twisting occurs near the nip of the rollers and, because of the relatively large difference between the yam and roller diameters, high yarn rotational speeds are achieved by the friction between the roller surface and the yarns. 

Air-jet Spinning: 
A system of staple-fibre spinning which utilizes air to apply the twisting couple to the yarn during its formation is known as Air-jet spinning. The air is blown through small holes arranged tangentially to the yarn surface and this causes the yarn to rotate. The majority of systems using this technique produce fasciated yarns, but by using two air jets operating in opposing twist directions it is possible to produce yarns with more controlled properties but of more complex structure. 

Centrifugal Spinning: 
A method of man-made fiber production in which the molten or dissolved polymer is thrown centrifugally in fibre form from the edge of a surface rotating at high speed. The term is also used to describe a method of yarn formation involving a rotating cylindrical container, in which, the yarn passes down a central guide tube and is then carried by centrifugal force to the inside of a rotating cylindrical container. 

Dispersion Spinning: 
A process in which the polymers that tend to an infusible, insoluble, and generally intractable character (e.g., polytetrafluoroethylene) are dispersed as fine particles in a carrier such as sodium alginate or sodium xanthate solutions is known as Dispersion spinning. These permit extrusion into fibers, after which the dispersed polymer is caused to coalesce by a heating process, the carrier being removed either by heating or by a dissolving process. 

Draw-Spinning: 
A process for spinning partially or highly oriented filaments in which the orientation is introduced prior to the first forwarding or collecting device. 

Dry Spinning (man-made fiber production): 
The spinning process involving conversion of a dissolved polymer into filaments by extrusion and evaporation of the solvent from the extrudate is known as Dry spinning. 

Flash Spinning: 
A modification of the accepted dry-spinning method in which a solution of a polymer is extruded at a temperature well above the boiling point of the solvent such that on emerging from the spinneret evaporation occurs so rapidly that the individual filaments are disrupted into a highly fibrillar form. 

Flyer Spinning: 
A spinning system in which yarn passes through a revolving flyer leg guide on to the package is known as Flyer spinning. The yarn is wound-on by making the flyer and spinning package rotate at slightly different speeds. 

Melt Spinning (man-made fiber production): 
The spinning process involving conversion of a molten polymer into filaments by extrusion and subsequent cooling of the extrude is known as Melt spinning. 

Reaction Spinning (man-made-fiber production): 
A process in which polymerization is achieved during the extrusion of reactants through a spinneret system. 

Ring Spinning: 
A spinning system in which twist is inserted in a yarn by using a revolving traveller is known as Ring spinning. The yarn is wound on since the rotational speed of the package is greater than that of the traveller. 

Wet Spinning (man-made-fiber production): 
The spinning process involving conversion of a dissolved polymer into filaments by extrusion into a coagulating liquid is known as Wet spinning. The extrusion may be directly into the coagulating liquid or through a small air-gap. In the latter case it may be known as dry-jet wet spinning or air-gap wet spinning.

 

 

What is Whitening Treatment? | Factors Influencing Whitening Process | Whitening Process for 100% Cotton | Whitening Process for Polyester-Cotton Blended Fabric

What is Whitening Treatment? | Factors Influencing Whitening Process | Whitening Process for 100% Cotton | Whitening Process for Polyester-Cotton Blended Fabric

Whitening :

Whitening is a chemical treatment, which is applied on fabric to make the fabric white at a desired level by bleaching and OBA treatment. 

Factors Influencing Whitening Process :
The factors influencing whitening process are as follows : 

a) pH of the bath 
b) Temperature of the bath, and 
c) Time required for the process. 
 

Process Requirements: 

Equipment Used 
Three types of Thies machines are used for whitening process. These are : 

1. Mini-soft
2. Eco-soft
3. Luft-roto

Accessories Used in Whittening 
Key accessories used in whitening process are : 

• Mixing tank
• Machine Tank
• Bohme meter
• pH meter
• Eye protecting glass
• Hand gloves
• Sewing machine
• Hand lifter for carrying the batch, and
• Gum boot.

Materials / Chemicals Used 
Following materials/chemicals are used in the whitening process : 

• Water
• Steam
• Compressed Air
• Wetting agent
• Detergent
• Sequestering agent
• Acid
• Anti-creasing agent
• Optical Brightener for Cotton & Polyester
• Caustic Soda,
• Hydrogen per Oxide, and
• Stabilizer, etc.

Operation Procedure

Whitening Process for 100% Cotton 
Steps of Whitening Process for 100% Cotton: 

The sequence for whitening process for 100% cotton fabric is as follows : 

1. Take water in bath at required level 
2. Add Detergent, Sequestering Agent, Anti-creasing Agent, Stabilizer 
3. Circulate the fabric for 5 minutes at 50⁰C 
4. Add Caustic Soda and circulate for 5 minutes at 50⁰C 
5. Add Hydrogen per Oxide and circulate for 5 minutes at 50⁰C
6. Add Optical Brightener agent and raise the temperature at 100⁰C 
7. Continue circulating the fabric for 50 minutes at constant temperature (100⁰C) 
8. Circulate the fabric and decrease the temperature at 60⁰C 
9. Check the shade with approved shade 
10. Rinse and Drain 
11. Add Acetic acid and circulate for 10 minutes at 50⁰C
12. Drain 
13. Unload 
 
Graphical Representation of Whitening Process of 100% Cotton 
The whitening process for 100% Cotton can be graphically presented as below :

Whitening Process for Polyester-Cotton Blended Fabric

Steps of Whitening Process for Polyester-Cotton Blended Fabric: 

The sequence of Whitening Process for Polyester-Cotton Blended fabric is as follows : 

1. Take water in bath at required level 
2. Add Detergent, Sequestering Agent, Anti-creasing Agent, Stabilizer 
3. Circulate the fabric for 5 minutes at 50⁰C
4. Add Caustic Soda and circulate for 5 minutes at 50⁰C
5. Add Hydrogen per Oxide and circulate for 5 minutes at 50⁰C 
6. Add Optical Brightener agent and raise the temperature at 110⁰C 
7. Continue circulating the fabric for 30 minutes at constant temperature (110⁰C) 
8. Circulate the fabric and decrease the temperature at 60⁰C 
9. Check the shade with approved shade 
10. Rinse and Drain 
11. Circulate the fabric for 10 minutes at 80⁰C 
12. Drain 
13. Add Acetic acid and circulate for 10 minutes at 50⁰C 
14. Drain 
15. Unload 

Graphical Representation of Whitening Process for Polyester Cotton Blended Fabric 
The whitening process for Polyester-Cotton blended fabric can be graphically presented as below :

 

List of Trimmings for a Shirt, Trouser and Jacket | Prepare a Trimming List of Shirt, Trouser and Jacket

List of Trimmings for a Shirt, Trouser and Jacket | Prepare a Trimming List of Shirt, Trouser and Jacket

Experiment name: Prepare a trimming list of shirt, trouser and jacket.

Introduction: 
The materials used in a garment except cloth to make a complete garment are called trimmings. Some trimmings can be seen from outside whether some are not. Again some trimmings are used for increasing beauty whether some for only function.

Objectives: 
To list out the trimming names.

List of trimmings: 
Now the trimming list for shirt, trouser and jacket is given below:

For shirt: 

1. Button 
2. Sewing thread 
3. Interlinning 
4. Linning
5. Label

For trouser: 

1. Button
2. Sewing thread
3. Linning
4. Zipper
5. Label

For jacket: 

1. Button
2. Sewing thread
3. Linning
4. Zipper
5. Label

Brief Description of Trimmings: 

Button: 
Buttons are the hardware items used in conjunction with button for the fastening of garments. The purpose of using buttons are-
Functional purpose.
Decorative purpose.

Types of button: 

1) according to no of holes: 
· 2-hole button.
· 4-hole button.
· Special button
– Shank button
– Snap button.
– Decorative button.

2) According to ligne no: 
According to ligne no there are various types of buttons. Lange is the measuring unit of button diameter.

Zipper: 
In making trousers, skirts and jackets chain or zipper is an essential component which is used to open or close the opening of garment.

Purpose of zipper: 
i) Functional purpose of zipper is as a part of a garment.
ii) Where zipper is used as a decorative purpose it increases the beauty of garment.

Types of zipper: 
Metal zipper.
Polyester or nylon coil zipper.
Plastic-molded zipper.

Label: 
No garments can be sold without some kind of label attached to it. Specially in case of exporting, label on a garment is a must. Label is a attached compound of garment on which important information regarding the garment are written on printed.

There are mainly 3-types of label: 
1) Main label.
2) Size label.
3) Care label.

Lining: 
Linings are generally a functional part of a garment. They are used variously to maintain the shape of a garment, to improve the hang and comfort by allowing it to slide over other garment.

Linings are joined to main garment by sewing and for this normal sewing machines are enough. The method of attaching lining to outer garments depends on the garment type and on whether it is fully or partially bagged out.

Interlining: 
Interlinings are used to support, reinforced control the shape of some areas of garments such as collars, cuffs, waist bands, facings and the front of coats. They are attached by fusing.

Conclusion: 
The experiment gives us an idea about different types of trimmings. I would like to give special thanks to our teacher. I am also grateful to our instructors. I think this experiment will be very helpful in my future life.

Introduction of Under Lap | Closed Lap | Open Lap

Introduction of Under Lap | Closed Lap | Open Lap

The Under Lap

The underlap shog occurs across the side of the needles remote from the hooks on the front of single-needle bar, and in the centre of double-needle bar, warp knitting machines. It supplies the warp yarn between one overlap and the next (Fig.A).The underlap shog generally ranges from 0 to 3 needle spaces, but it might be 14 needle spaces or more depending upon the design of the machine and the fabric structure (although efficiency and production speed will be correspondingly reduced with long underlaps).

A.Under lap shog

Underlaps as well as overlaps are essential in warp knitted structures in order to join the wales of loops together but they may be contributed by different guide bars.

The Closed Lap 
A closed lap is produced when a subsequent underlap shogs in the opposite direction to the preceding overlap, thus lapping the same yarn around the back as well as around the front of the needle (Fig.B).

B.Closed Lap

The Open Lap 
An open lap is produced either when a subsequent underlap is in the same direction as the preceding overlap (Fig.C) or an underlap is omitted so that the overlap of the next knitting cycle commences in the needle space where the previous overlap finished. Closed laps are heavier, more compact, more opaque, and less extensible than open laps produced from the same yarn at a comparable knitting quality. 

C.Open Lap

 

 

History of Weaving in According with Evolution of Weaving, Power Looms, Automation, Shedding Mechanisms, Weft Insertion Systems

History of Weaving in According with Evolution of Weaving, Power Looms, Automation, Shedding Mechanisms, Weft Insertion Systems

HISTORY OF WEAVING 

 

Evolution of Weaving

1. Egyptians made woven fabrics some 6000years ago .
2. Chinese made fine fabrics from silk over 4000 years ago.
3. A shedding mechanism was originally invented in China in the 3rd century and introduced in Europe.
4. In 12th century , completely wooden hand looms were used as standard designs in England.
5. The developments in the design and performance of looms have taken place during the past 850 years.
6. The fly shuttle , invented in 1733 by John Kay, was hand operated.
7. It was an important cornerstone to improve the productivity.
8. This shuttle, running on four wheels, was moving over the lower side of the warp sheet. 
9. Two wooden tenders connected to a small cord commanded by the hand were used to propel the shuttle. The weaver sitting in the middle of the loom threw the shuttle by pulling the cord very easily.

Hand loom

Power Looms

1. E.Cartwright invented the power loom in 1785 
2. In the early 1800s , looms made of cast iron were operated by power .
3. In the 1830s, there were some 100,000 shuttle looms operating in England.
4. In 1895, many looms, all driven by an electric engine were invented and then became spread.
5. At the beginning of 1930’s, eventually, each weaving machine driven individually by an electric motor was developed, this loom drive concept has remained in use until the present.

Automation

1. The automatic loom stopping system was invented by R.Miller in England in 1796. The loom was automatically stopped when a short pick occurred.
2. In 1894 Northrop devised a means for automatic weft replenishment without stopping the loom which was called automatic loom .

Shedding Mechanisms

1. The first dobby operated by a punched card was invented by B. Bouchone in 1725.
2. A machine controlling bundles of harness cords with healds was constructed by J.M. Jacquard in 1801.
3. The first shuttle change motion enabling weft threads of different colors to be inserted was constructed by J.P. Reid and T. Johnson in 1835.
4. One significant invention in the field of design was that of Keighley dobby by Hattersley and Smith in 1867 .
5. Rotary dobbies are manufactured in 1990s.

Weft Insertion Systems

1. Projectile w.m. was invented in 1924by an engineer named Rossmann became commercial in 1953.
2. The first patent for the rapier w.m.was granted in 1898, then followed the Gabler system in 1925 and the Dewas system in 1930. Production of rapier w. m. started in 1972.
3. The first air-jet system was invented in 1914 but it became important commercially after 1980’s.
   
4. Continuous weft insertion on a circular w.m. was proposed before the end of the 19th century.
5. After mid 90s, multi phase w.m. has showed new developments.

Block Printing Style | Procedure of Block Printing on Fabric | After Treatment of Block Printing

Block Printing Style | Procedure of Block Printing on Fabric | After Treatment of Block Printing

Block Printing

The printing of fabric by hand, using carved wooden or linoleum blocks, as distinguished fromprinting by screens or roller is called block printing. Block printing is a special form of printing first developed in China. The earliest known example with an actual date is a copy of the Diamond Sutra from 868 A.D (currently in the British Museum), though the practice of block printing is probably about two thousand years old.

Procedure of Block Printing 

The fabric to be printed is washed free of starch and soft bleached if the natural gray of the fabric is not desired. If dyeing is required as in the case of saris where borders or the body is tied and dyed it is done before printing. The fabric is again washed to remove excess dye and dried thoroughly. The fabric is stretched over the printing table and fastened with small pins. This is an important stage as there should be a uniform tension in the fabric and no ripples. Color is mixed separately in another room. Usually pigment dyes are used for cotton.

The first step in block printing is the production of the original document. This is laid on a large, smooth wooden block and fixed into place, reversed. Next, craftsmen of various skill levels, ranging from master carvers for the fine work to less talented artisans for cheaper blocks or less important sections, carve the original painted, drawn or written image into the block of wood. The block can now be covered with ink and used in a press to create duplicates of the original. 

 

Color paste must be applied to the block surface in a controlled manner, and this was achieved by using a ‘sieve’. A small tub was nearly filled with a starch paste and a waterproof fabric, stretched on a frame, rested on the paste. A piece of woolen fabric was stretched on a slightly smaller frame and fastened to make the sieve. The sieve as saturated with color paste and placed on the waterproof fabric. For each impression, the ‘tiered’ (a boy) spread the color paste on the top surface of the woolen sieve with a large brush and the printer charged the block by pressing it on the wool. The block was then carefully positioned on the fabric, using the pitch pins as guides, and struck with a mallet. After printing a table length with the first block, the second was printed and then any others required to complete the design. 

After Treatment of Block Printing
The fabric, after printing is dried out in the sun. This is part of the fixing process or aftertreatment of printing. It is then rolled in wads of newspapers to prevent the dye from adhering to other layers and steamed in boilers constructed for the purpose. Silks are also steamed this way after printing. After steaming, the material is washed thoroughly in large quantities of water and dried in the sun, after which it is finished by ironing out single layers, which fix the color permanently.