Definition and Classification of Textile Neps | Count of Neps

Any small entanglement of textile fibers that can not be unraveled, formed during carding or ginning.

Classification of Neps
For cotton fiber; there are five types of Neps. These are –

Process Neps: Commonly produced by faulty carding or up to spinning yarn.

Mixed Neps: Fibres tangle around a foreign materials. For instance – Grit.

Immature Neps: Generally form by processing immature fibre.

Homogeneous Dead Neps: A tangle of nearly all dead fibres.

Fuzz Neps: A fault of short fuzz fibers .

Count of Neps
Nep count is the no. of neps per 100 square inches of card web forming ( a standerd hank of sliver of 12 NE on a 40 inch wide card).

How To Measure the Count of Neps?
At first a web is collected from the card placed on a 10 inch × 10 inch black board. Then the neps are counted and the no. of neps found is corrected fro any difference in hank or card width.
Mathematically, Nep Count, n = m × 100 [ m = no. of neps per inch square card web].

Define Jute Fiber | Chemical Composition of Jute Fiber | Defects in Jute

A bast fiber used for sacking, burlap, and twine as a backing material for tufted carpets. Jute is one of the most affordable natural fibres and is second only to cotton in amount produced and variety of uses of vegetable fibres. Jute fibres are composed primarily of the plant materials cellulose (major component of plant fibre) and lignin (major components of wood fibre).

Chemical Composition of Jute Fiber

• Cellulose → 65.2%
• Hemi-cellulose → 22.2%
• Lignin → 12.5%
• Water Soluble matter → 1.5%
• Fat and Wax → 0.6%

Defects in Jute

Rooty Jute: in these jute the lower parts of jute fires contain barks.

Specky jute: this defects occur because of insufficient washing which causes the outer barks to adhere in some places

Croppy Jute: this is a defect where the top end of the fibre become rough and hard. It is usually caused by careless steeping.

Knotty jute: the jute fibres contain knots in places and it is caused by insect bite or punctures.

Dezed or Dead fibres: due to over retting in moist condition, the fibre becomes dull, lose strength and becomes inferior for spinning.

Runners: this is a defect where long and hard barky ribbon of fibres remains in jute fibre.

Hunka: defects caused by non-removal of dried up base and hard bark from the fibres.

Mossy jute: fibres from short plants that cannot be properly stripped and cleaned contain broken piece of jute sticks etc.

Flabby or Fluffy jute: due to careless stripping, fibre loses firmness and becomes flabby and hairy

Heart damage: These defects occur when jute fibre contains excess moisture when baled. The centre of the bale becomes badly tendered and in some cases fibres are reduced to powder.

Rayon Fiber | Characteristics of Rayon Fiber | Manufacturing Process ofViscose Rayon | End Uses of Rayon Fiber

Rayon is the oldest commercial manmade fiber. It is a manufactured fiber composed of regenerated cellulose, as well as manufactured fibers composed of regenerated cellulose in which substituents have replaced not more than 15% of the hydrogens of the hydroxyl groups. Rayon fibers include yarns and fibers made by the viscose process, the cuprammonium process, and the now obsolete nitrocellulose and saponified acetate processes. Generally, in the manufacture of rayon, cellulose derived from wood pulp, cotton linters, or other vegetable matter is dissolved into a viscose spinning solution. The solution is extruded into an acid-salt coagulating bath and drawn into continuous filaments. Groups of these filaments may be made in the form of yarns or cut into staple.

Characteristics of Rayon Fiber :

1. Highly absorbent
2. Soft and comfortable
3. Easy to dye
4. Drapes well

The drawing process applied in spinning may be adjusted to produce rayon fibers of extra strength and reduced elongation. Such fibers are designated as high tenacity rayons, which have about twice the strength and two-thirds of the stretch of regular rayon. An intermediate grade, known as medium tenacity rayon, is also made. Its strength and stretch characteristics fall midway between those of high tenacity and regular rayon.

Types of Rayons

Rayon fibers are engineered to possess a range of properties to meet the demands for a wide variety of end uses. Types of rayon fiber are given below:

1. High wet modulus rayon
2. Polynosic rayon
3. Specialty rayons
4. Super absorbent rayons
5. Tencel rayon
6. Lyocell

Manufacturing Process of Viscose Rayon:

While there are many variations in the manufacturing process that exploit the versatility of the fiber, the following is a description of the procedure that is used in making regular or viscose rayon.

Regardless of whether wood pulp or cotton linters are used, the basic raw material for making rayon must be processed in order to extract and purify the cellulose. The resulting sheets of white, purified cellulose are then treated to form regenerated cellulose filaments. In turn, these filaments are spun into yarns and eventually made into the desired fabric.

The process of manufacturing viscose rayon consists of the following steps mentioned, in the order that they are carried out: (1) Steeping, (2) Pressing, (3) Shredding, (4) Aging, (5) Xanthation, (6) Dissolving, (7)Ripening, (8) Filtering, (9) Degassing, (10) Spinning, (11) Drawing, (12) Washing, (13) Cutting. The various steps involved in the process of manufacturing viscose are explained below.

Figure : Process of manufacture of viscose rayon fiber

1. Steeping: 

Cellulose pulp is immersed in 17-20% aqueous sodium hydroxide (NaOH) at a temperature in the range of 18 to 25°C in order to swell the cellulose fibers and to convert cellulose to alkali cellulose.

(C6H10O5)n + nNaOH —-> (C6H9O4ONa)n + nH2O
 

2. Pressing: 

The swollen alkali cellulose mass is pressed to a wet weight equivalent of 2.5 to 3.0 times the original pulp weight to obtain an accurate ratio of alkali to cellulose.
 

3.  Shredding: 

The pressed alkali cellulose is shredded mechanically to yield finely divided, fluffy particles called “crumbs”. This step provides increased surface area of the alkali cellulose, thereby increasing its ability to react in the steps that follow.
 

4.  Aging: 

The alkali cellulose is aged under controlled conditions of time C) in order to depolymerize the°and temperature (between 18 and 30 cellulose to the desired degree of polymerization. In this step the average molecular weight of the original pulp is reduced by a factor of two to three. Reduction of the cellulose is done to get a viscose solution of right viscosity and cellulose concentration.
 

5. Xanthation: 

In this step the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulphide under controlled temperature (20 to 30°C) to form cellulose xanthate.

(C6H9O4ONa)n + nCS2 ——> (C6H9O4O-SC-SNa)n

Side reactions that occur along with the conversion of alkali cellulose to cellulose xanthate are responsible for the orange color of the xanthate crumb and also the resulting viscose solution. The orange cellulose xanthate crumb is dissolved in dilute sodium hydroxide at 15 to 20 °C under high-shear mixing conditions to obtain a viscous orange colored solution called “viscose”, which is the basis for the manufacturing process. The viscose solution is then filtered (to get out the insoluble fiber material) and is deaerated.
 

6.  Dissolving: 

The yellow crumb is dissolved in aqueous caustic solution. The large xanthate substituents on the cellulose force the chains apart, reducing the interchain hydrogen bonds and allowing water molecules to solvate and separate the chains, leading to solution of the otherwise insoluble cellulose. Because of the blocks of un-xanthated cellulose in the crystalline regions, the yellow crumb is not completely soluble at this stage. Because the cellulose xanthate solution (or more accurately, suspension) has a very high viscosity, it has been termed “viscose”.
 

7. Ripening: 

The viscose is allowed to stand for a period of time to “ripen”. Two important process occur during ripening: Redistribution and loss of xanthate groups. The reversible xanthation reaction allows some of the xanthate groups to revert to cellulosic hydroxyls and free CS2. This free CS2 can then escape or react with other hydroxyl on other portions of the cellulose chain. In this way, the ordered, or crystalline, regions are gradually broken down and more complete solution is achieved. The CS2 that is lost reduces the solubility of the cellulose and facilitates regeneration of the cellulose after it is formed into a filament.

(C6H9O4O-SC-SNa)n + nH2O —-> (C6H10O5)n + nCS2 + nNaOH
 

8.  Filtering: 

The viscose is filtered to remove undissolved materials that might disrupt the spinning process or cause defects in the rayon filament.
 

9.  Degassing: 

Bubbles of air entrapped in the viscose must be removed prior to extrusion or they would cause voids, or weak spots, in the fine rayon filaments.
 

10.  Spinning - (Wet Spinning): 

Production of Viscose Rayon Filament: The viscose solution is metered through a spinnerette into a spin bath containing sulphuric acid (necessary to acidify the sodium cellulose xanthate), sodium sulphate (necessary to impart a high salt content to the bath which is useful in rapid coagulation of viscose), and zinc sulphate (exchange with sodium xanthate to form zinc xanthate, to cross link the cellulose molecules). Once the cellulose xanthate is neutralized and acidified, rapid coagulation of the rayon filaments occurs which is followed by simultaneous stretching and decomposition of cellulose xanthate to regenerated cellulose. Stretching and decomposition are vital for getting the desired tenacity and other properties of rayon. Slow regeneration of cellulose and stretching of rayon will lead to greater areas of crystallinity within the fiber, as is done with high-tenacity rayons.

The dilute sulphuric acid decomposes the xanthate and regenerates cellulose by the process of wet spinning. The outer portion of the xanthate is decomposed in the acid bath, forming a cellulose skin on the fiber. Sodium and zinc sulphates control the rate of decomposition (of cellulose xanthate to cellulose) and fiber formation.

(C6H9O4O-SC-SNa)n + (n/2)H2SO4 —> (C6H10O5)n + nCS2 + (n/2)Na2SO4

Elongation-at-break is seen to decrease with an increase in the degree of crystallinity and orientation of rayon.
 

11. Drawing: 

The rayon filaments are stretched while the cellulose chains are still relatively mobile. This causes the chains to stretch out and orient along the fiber axis. As the chains become more parallel, interchain hydrogen bonds form, giving the filaments the properties necessary for use as textile fibers.
 

12.  Washing: 

The freshly regenerated rayon contains many salts and other water soluble impurities which need to be removed. Several different washing techniques may be used.
 

13.  Cutting: 

If the rayon is to be used as staple (i.e., discreet lengths of fiber), the group of filaments (termed “tow”) is passed through a rotary cutter to provide a fiber which can be processed in much the same way as cotton . 

Major End Uses of Rayon Fiber :

1. Apparel: Accessories, blouses, dresses, jackets, lingerie, linings, millinery, slacks, sportshirts, sportswear, suits, ties, work clothes 

2. Home Furnishings: Bedspreads, blankets, curtains, draperies, sheets, slipcovers, tablecloths, upholstery 

3. Industrial Uses: Industrial products, medical surgical products, nonwoven products, tire cord 

4. Other Uses: Feminine hygiene products

Introduction of Glass Fiber | Types of Glass Fiber | Properties ofGlass Fiber | Manufacturing Processes of Glass Fiber | Uses of GlassFiber or Glass Yarn

Glass fiber

Glass fiber also called fiberglass. It is material made from extremely fine fibers of glass Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favorable when compared to metals, and it can be easily formed using molding processes. Glass is the oldest, and most familiar, performance fiber. Fibers have been manufactured from glass since the 1930s.



Types of Glass Fiber
As to the raw material glass used to make glass fibres or nonwovens of glass fibres, the following classification is known:

1. A-glass: With regard to its composition, it is close to window glass. In the Federal Republic of Germany it is mainly used in the manufacture of process equipment.

2. C-glass: This kind of glass shows better resistance to chemical impact.

3. E-glass: This kind of glass combines the characteristics of C-glass with very good insulation to electricity.

4. AE-glass: Alkali resistant glass.

Generally, glass consists of quartz sand, soda, sodium sulphate, potash, feldspar and a number of refining and dying additives. The characteristics, with them the classification of the glass fibres to be made, are defined by the combination of raw materials and their proportions. Textile glass fibres mostly show a circular

Properties of Glass Fiber
Glass fibers are useful because of their high ratio of surface area to weight. However, the increased surface area makes them much more susceptible to chemical attack. By trapping air within them, blocks of glass fiber make good thermal insulation, with a thermal conductivity of the order of 0.05 W/(mK).

The strength of glass is usually tested and reported for “virgin” or pristine fibers those which have just been manufactured. The freshest, thinnest fibers are the strongest because the thinner fibers are more ductile. The more the surface is scratched, the less the resulting tenacity. Because glass has an amorphous structure, its properties are the same along the fiber and across the fiber. Humidity is an important factor in the tensile strength. Moisture is easily adsorbed, and can worsen microscopic cracks and surface defects, and lessen tenacity.

In contrast to carbon fiber, glass can undergo more elongation before it breaks. There is a correlation between bending diameter of the filament and the filament diameter. The viscosity of the molten glass is very important for manufacturing success. During drawing (pulling of the glass to reduce fiber circumference), the viscosity should be relatively low. If it is too high, the fiber will break during drawing. However, if it is too low, the glass will form droplets rather than drawing out into fiber.

Glass Fiber Manufacturing Processes
After the initial process of melting glass and passing it through spinnerets, continuous filaments or staple fibers of glass are manufactured by two different methods.

Continuous Filament Process
In this process, continuous filaments of indefinite length is produced. The molten glass passes through spinnerets having hundreds of small openings. These strands of multiple filaments are carried to winder revolving at very high speed of more than 2 miles per km. This process draws out the fibers in parallel filaments of the diameter of the openings. A sizing or a binder is applied to facilitate the twisting and winding process and to prevent breakage during yarn formation. After winding, filaments are further twisted and plied to make yarns by methods similar to those for making other continuous filament yarns. The sizing is removed through volatizing in an oven. These yarns are used for making such items as curtains and drapes.

Staple Fiber Process
Fibers with long-staple qualities are manufactured through staple fiber process. There are many methods for producing such fibers.

In one of such methods, the molten glass flows through the small holes of bushing, where jets of compressed air shake the thin streams of molten glass into fine fibers. These fibers vary in length ranging from 8 to 15 inches. The fibers fall through a spray of lubricant and a drying flame onto e revolving drum where they form into a thin web. These fibers in the form of web are gathered from the drum into a sliver. Yarn is then made from this sliver by similar methods that are adopted for making cotton or wool yarns. These yarns are used for fabrics for industrial purposes where insulation is required.

In yet another method, the ends of the glass rods are melted from which drops of glass fall away drawing off glass filaments after them onto a speedily revolving cylinder where they are wound parallel to each other. A web of sliver is formed if the cylinder moves sideways. Sometimes, the staple may be thrown off the cylinder onto a stationary sieve where it forms a sliver. In either conditions, the sliver is then converted into spun yarn.

The staple fiber, if subjected to oven, is compressed to the desired thickness and the binder which was earlier applied, is cured. This permanently binds the fibers.

Production:
The subsequent manufacture of glass fibres may be executed to the direct melting process. However, in most cases glass rods or balls are made first which then may undergo a variety of further processes.

Nozzle-Drawing:
As can be seen in Fig. 1-50, the glass fed in is melted in a heated melt tub at 1250–1400oC. Then, it emerges at the bottom of the melt tub from nozzle holes of 1–25 mm diameter and it is taken off and drawn. The filaments solidify and are finished and wound. One can find them in the shops as various kinds of “glass silk”. To make them into webs, the filaments are cut to length (mostly, between 6 and 25 mm).

Manufacture of glass melt

Processes to make glass fibres

Nozzle-Blowing:
The same as with nozzle-drawing, glass balls are melted in the tub. The melt emerging from the nozzle holes is then taken by pressed air, which draws the liquid glass so as to make fibres of 6–10 um diameter. A fluttering effect is caused by the flow of pressed air, which results in fibres of lengths from 50 to 300 mm. A lubricant is put on and the fibres are laid down on a sieve drum which sucks them in. The dry web received is held together by the long fibres, the short ones lying in between them as a filling material. Then, the slivers of glass fibre material are cut.

Rod-Drawing:
By means of a burner, bundles of glass rods are melted at their bottom ends. This results in drops which, as they fall down, draw filaments after them. The filaments are taken by a rotating drum, a squeegee laying them down onto a perforated belt. Thus, a dry web is received which can be wound as glass fibre slivers. – Machine performance being limited by the number of glass rods fed in, the rotating drum may be combined with nozzle-drawing, which results in drum-drawing. This multiplies machine performance. The dry web is again laid down onto a perforated belt and solidified or, after winding it so as to receive slivers, cut for further processing on machines producing wetlaid nonwovens. Using and processing glass fibres is not without any problems. For example, fine pieces of broken fibres may disturb if the work place is not well prepared for the purpose. Using the nonwovens to manufacture glass-fibre reinforced plastics, it is important the surface of the plastic material is fully even. Ends of fibre looking out may be pulled out or loosened by outward stress (temperature, gases, liquids), which may influence material characteristics. In some cases, it is
advisable to cover up such layers of glass fibre with suitable chemical fibres.

Uses of Glass Fiber or Glass Yarn
Glass fiber is manufactured in a wide range of fine diameters. Some of them are so fine that they can be seen only through a microscope. This quality of fineness contributes greatly to the flexibility of glass fibers. Various manufacturers produce different types of glass fibers for different end uses. Glass fibers them are used for various purpose.

1. For making home furnishings fabrics;
2. For making apparels and garments; and
3. For the purpose tires and reinforced plastics.

There are certain glass fibers that can resist heat upto 7200oC and can withstand forces having speed of 15,000 miles per hour. These types of glass fibers are used as

1. Filament windings around rocket cases;
2. Nose cones;
3. Exhaust nozzles; and
4. Heat shields for aeronautical equipment

Some other types of glass fibers are embedded into various plastics for strength. These are used in

1. Boat hulls and seats;
2. Fishing rods; and
3. Wall paneling

Some other types of glass fibers are used for reinforcing electrical insulation. Yet other types are used as batting for heat insulation in refrigerators and stoves.

Introduction of Synthetic Fiber | Production Process of DifferentSynthetic Fibers

Most synthetic and cellulosic manufactured fibers are created by “extrusion” — forcing a thick, viscous liquid (about the consistency of cold honey) through the tiny holes of a device called a spinneret to form continuous filaments of semi-solid polymer.

In their initial state, the fiber-forming polymers are solids and therefore must be first converted into a fluid state for extrusion.

This is usually achieved by melting, if the polymers are thermoplastic synthetics (i.e., they soften and melt when heated), or by dissolving them in a suitable solvent if they are non-thermoplastic cellulosics. If they cannot be dissolved or melted directly, they must be chemically treated to form soluble or thermoplastic derivatives. Recent technologies have been developed for some specialty fibers made of polymers that do not melt, dissolve, or form appropriate derivatives. For these materials, the small fluid molecules are mixed and reacted to form the otherwise intractable polymers during the extrusion process.

The Spinneret 
The spinnerets used in the production of most manufactured fibers are similar, in principle, to a bathroom shower head. A spinneret may have from one to several hundred holes. The tiny openings are very sensitive to impurities and corrosion. The liquid feeding them must be carefully filtered (not an easy task with very viscous materials) and, in some cases, the spinneret must be made from very expensive, corrosion-resistant metals. Maintenance is also critical, and spinnerets must be removed and cleaned on a regular basis to prevent clogging.

As the filaments emerge from the holes in the spinneret, the liquid polymer is converted first to a rubbery state and then solidified. This process of extrusion and solidification of endless filaments is called spinning, not to be confused with the textile operation of the same name, where short pieces of staple fiber are twisted into yarn. There are four methods of spinning filaments of manufactured fibers: wet, dry, melt, and gel spinning.

Wet Spinning 

Wet spinning is the oldest process. It is used for fiber-forming substances that have been dissolved in a solvent. The spinnerets are submerged in a chemical bath and as the filaments emerge they precipitate from solution and solidify.

Because the solution is extruded directly into the precipitating liquid, this process for making fibers is called wet spinning. Acrylic, rayon, aramid, modacrylic and spandex can be produced by this process.

Dry Spinning 

Dry spinning is also used for fiber-forming substances in solution. However, instead of precipitating the polymer by dilution or chemical reaction, solidification is achieved by evaporating the solvent in a stream of air or inert gas.

The filaments do not come in contact with a precipitating liquid, eliminating the need for drying and easing solvent recovery. This process may be used for the production of acetate, triacetate, acrylic, modacrylic, PBI, spandex, and vinyon.

Melt Spinning
In melt spinning, the fiber-forming substance is melted for extrusion through the spinneret and then directly solidified by cooling. Nylon, olefin, polyester, saran and sulfar are produced in this manner.

Melt spun fibers can be extruded from the spinneret in different cross-sectional shapes (round, trilobal, pentagonal, octagonal, and others). Trilobal-shaped fibers reflect more light and give an attractive sparkle to textiles.

Pentagonal-shaped and hollow fibers, when used in carpet, show less soil and dirt. Octagonal-shaped fibers offer glitter-free effects. Hollow fibers trap air, creating insulation and provide loft characteristics equal to, or better than, down.

Detailed production flowcharts:
•   Acrylic	•   Nylon (Polyamide)	•   Polyester

Gel Spinning

Gel spinning is a special process used to obtain high strength or other special fiber properties. The polymer is not in a true liquid state during extrusion. Not completely separated, as they would be in a true solution, the polymer chains are bound together at various points in liquid crystal form. This produces strong inter-chain forces in the resulting filaments that can significantly increase the tensile strength of the fibers. In addition, the liquid crystals are aligned along the fiber axis by the shear forces during extrusion. The filaments emerge with an unusually high degree of orientation relative to each other, further enhancing strength. The process can also be described as dry-wet spinning, since the filaments first pass through air and then are cooled further in a liquid bath. Some high-strength polyethylene and aramid fibers are produced by gel spinning.

Stretching and Orientation

While extruded fibers are solidifying, or in some cases even after they have hardened, the filaments may be drawn to impart strength. Drawing pulls the molecular chains together and orients them along the fiber axis, creating a considerably stronger yarn.

Introduction of Nylon 6 Fiber | Spinning Process of Nylon 6 Fiber |Manufacturing Process of Nylon 6 Fiber

Nylon 6 Fiber

The synthetic fibres also called as chemical fibres are the synthesised polymers, which are not found in nature. There are different types of synthetic fibres of which the manufacturing process of nylon is discussed in this unit. Nylon is the first man made synthetic fibre (pure chemical fibre).

Nylon 6 Fiber

As defined by the Federal Trade Commission (FTC), nylon “is a long – chain synthetic polyamide in which less than 85 per cent of the amide linkages are attached to two aromatic rings”.

Manufacturing of Nylon 6
The raw material for manufacturing Nylon 6 is coal.Cyclohexane oxime is produced by a series of chemical reactions on coal. Cyclo heaxaneoxime is then treated with sulphuric acid to form caprolactum. The caprolactum is a monomer with 6 carbon atoms that are polymerized to from chains of caprolactum. Polymerization is done by gently heating it in a steam – jacked stainless steel vessel. The solution is stabilised as a super polymer under constant steam and pressure.

Nylon may be delustered by adding the delustering agents like titanium di oxide, barium sulphate, zinc oxide, and zinc sulphate. The molten nylon 6 polymer is allowed to flow onto a slowly revolving casting wheel. These are sprayed with cold water, which hardens it into milky white ribbons. The ribbons are transformed into flakes that are sent for spinning and are then drawn into the fibre form.

Spinning of nylon 6:

Spinning of Nylon 6
The spinning of the nylon fibres is carried out with melt spinning. There are two methods of melt spinning:

1. grid spinning
2. extruder spinning.

Grid spinning is employed for the production of finer filaments.The nylon flakes are made to fall on a hot grid that melts the nylon flakes. The molten nylon is pumped through a sand filter to the spinneret. The type of filament produced depends upon the number of holes on the spinneret, the size and the shape of the holes. The molten nylon as extruded from the spinneret solidifies and forms filaments as exposed to the air. Extruder spinning is generally used for heavier yarns.

The nylon chips flow by gravity into a device that forces them by screw action through the heated zones. The combined action of the heat and screw pressure melts the chips. The molten polymer is then extruded through the spinneret, which solidifies when the polymer comes in contact with the air.

Drawing:
The filaments obtained from spinning are stretched by drawing process. The drawing process is accomplished in two stages: unwinding the yarn from one godet, or wheel, winding it onto another godet that is rotating much faster. The speed of the second wheel determines the amount of cold-drawing or stretching. The yarn from the second godet is wrapped on a cylindrical tube called a pirn.

The filaments can be stretched from 2 to 7 times their original length. The molecules in the filament structure straighten out, become parallelized, and are brought very close together.

Ginning | Cotton Ginning Process | Types of Ginning

Ginning

Ginning is the process of separating the cotton fibers from the cotton seeds. Perfect ginning operation would be performed if the separation of fibers from seed was effected without the slightest injury to either seeds or to the fiber. A cotton gin is a machine that quickly and easily separates the cotton fibers from the seeds, a job previously done by hand. These seeds are either used again to grow more cotton or, if badly damaged, are disposed of. It uses a combination of a wire screen and small wire hooks to pull the cotton through the screen, while brushes continuously remove the loose cotton lint to prevent jams. The term “gin” is an abbreviation for engine, and means “machine”.

Types of Ginning

Previous to the introduction of Modern Machinery, ginning was performed by hand or by machines of a primitive character such as the “Foot Roller” and its improvement the “Churka”.

As the cotton industry developed, greater production than these were capable of was necessary, and machines driven by power were introduced. Numerous forms of gins have been tried, but at the present time only three are used to any large extent. They are

1. Knife Roller Gin / Roller Gin

2. Saw Gin
3. Macarthy Gin

Three Types Of Macarthy Gins

i. Single acting Macarthy Gin.

ii. Double acting Macarthy Gin

iii. Double roller Macarthy Gin / Double Roller Gin

Properties of Fiber | Properties of Textile Fiber

Properties of Textile Fiber:
To be a textile fiber it has some properties. The properties of textile fiber are given below:

Normally properties of textile fiber are three types
A) Physical Properties 

B) Mechanical Properties 

C) Chemical Properties
 
A) Physical Properties
1. Length
2. Fineness
3. Crimp
4. Maturity
5. Lusture
6. Softness
7. Resiliency
8. Work of rupture
9. Density
10. Appearance
11. Flexibility
12. Toughness
13. Elorgation

B)Mechanical Properties
1. Strength
2. Elasticity
3. Extensibility
4. Rigidity 

C) Chemical Properties
1. Solubility in aqueous salt
2. Solubility in organic salt 

Without above that properties fiber has also 

1. Thermal Prperties

2. Torsional Properties

Introduction of Textile Fiber | Classification of Textile Fiber

Fiber

Fiber or fibre is classes of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together. Human uses for fibers are diverse. They can be spun into filaments, string or rope, used as a component of composite materials or matted into sheets to make products such as paper or felt.Fibers are often used in the manufacture of other materials. Synthetic fibers can be produced very cheaply and in large amounts compared to natural fibers, but natural fibers enjoy some benefits, such as comfort, over their man-made counterparts.

Types of Fiber:
Generally two types of  Textile fiber.
1. Natural fiber.
2. Manmade fiber.

Natural fiber
Natural fibers include those produced by plants, animals, and geological processes. They are biodegradable over time. They can be classified according to their origin.

Man made fiber
Synthetic or man-made fibers generally come from synthetic materials such as petrochemicals. But some types of synthetic fibers are manufactured from natural cellulose; including rayon, modal, and the more recently developed Lyocell. Cellulose-based fibers are of two types, regenerated or pure cellulose such as from the cupro-ammonium process and modified or derivitized cellulose such as the cellulose acetates. 

Classification of Textile Fiber

 

Fiber

What is Textile Fiber? | Types of Textile Fiber

Fiber:
It is defined as one of the delicate, hair portions of the tissues of a plant or animal or other substances that are very small in diameter in relation to there length. A fiber is a material which is several hundred times as long as its thick.

Textile Fiber:
Textile fiber has some characteristics which differ between fiber to Textile fiber. Textile fiber can be spun into a yarn or made into a fabric by various methods including weaving, knitting, braiding, felting, and twisting. The essential requirements for fibers to be spun into yarn include a length of at least 5 millimeters, flexibility, cohesiveness, and sufficient strength. Other important properties include elasticity, fineness, uniformity, durability, and luster.

Banana fiber is one kind of fiber but it is not a textile fiber. Because it can not fill up the above properties. So we can say that all fiber are not textile fiber.

Types of Textile Fiber:
Generally two types of fiber.
1. Natural fiber.
2. Manmade fiber.

Natural Fiber:
Natural fibers include those produced by plants, animals, and geological processes. They are biodegradable over time. They can be classified according to their origin.

A class name for various genera of fibers (including filaments) of: 

(1) animal (i.e., silk fiber and wool fiber); 

(2) mineral (i.e., asbestos fiber); or

(3) vegetable origin (i.e., cotton fiber, flax fiber, jute fiber, and ramie fiber).

Manmade Fiber:
It is also known as Manufactured fiber. Synthetic or man-made fibers generally come from synthetic materials such as petrochemicals. But some types of synthetic fibers are manufactured from natural cellulose; including rayon, modal, and the more recently developed Lyocell. A class name for various genera of fibers (including filaments) produced from fiber-forming substances which may be: 

(1) Polymers synthesized from chemical compounds, e.g., acrylic fiber, nylon fiber, polyester fiber, polyethylene fiber, polyurethane fiber, and polyvinyl fibers; 

(2) Modified or transformed natural polymers, e.g., alginic and cellulose-based fibers such as acetates fiber and rayons fiber; and 

(3) Minerals, e.g., glasses. The term manufactured usually refers to all chemically produced fibers to distinguish them from the truly natural fibers such as cotton, wool, silk, flax, etc.e.g: Glass 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.)

Milk or Casein Fiber | Manufacturing Process of Milk Fiber | Application of Milk Fiber

Milk Fiber:Milk fiber is a blend of casein protein and the chemical acrylonitrile, which is used to make acrylic. It’s made using a process that is similar to rayon/viscose, but because it’s a regenerated protein fiber and not a regenerated cellulose fiber, it reacts like wool. That means that it dyes like wool and even smells like wool when burned, according to Kiplinger. 

Milk fiber

Characteristics of Milk Fiber:

1. In milk fibre,the natural protein humectant factor is present,which makes the skin delicate and smooth…
2. It absorbs moisture very well as it is hygroscopic in nature.
3. It is antibacterial and antifungal as amino acids present in the fibre.
4. It is glossy and luxurious in appearance,feel and comfortability, just like silk..
5. It is very easy to dye and can be dyed under normal temperature.














































6. It can be blended well with other different fiares,such as tencel,cotton,bamboo,modal fibre.

History of Casein or Milk Fiber:
According to Euroflax Industries, milk fiber was invented in 1930’s in both Italy and America and was called “milk casein.” Huh. Who knew? And here I thought it was some newfangled invention. But apparently it’s been around for a while. Whoa. For a longwhile! Crazily enough, casein was inventedway before the 1930s – apparently they’ve discovered that many churches from the 14th and 15th centuries were painted with casein-based paints – the colors are still bright and unfaded even to this day! Well, apparently this milk casein stuff is great for paint. But how does that connect with milk fiber?

Apparently “milk casein” fiber was used in many clothing and household items in America and Europe during the 1930s and ’40s, says Joan Kiplinger of Fabrics.net. It was substitute for wool, which was needed by men on the front lines. However, it fell out of use after WWII ended and newer, cheaper synthetics such as nylon grew in popularity. The fiber was blended with other natural fibers and known under the brand names of Aralac, Lanatil and Merinova, for those of you checking your vintage clothing labels. While these brands’ fabrics were very similar to wool and could be dyed by the same processes, apparently there were some flaws with the milk casein fiber – namely, that it was not as strong and firm, nor as elastic as wool, and the fibers mildewed easily when they got damp.

Production Process of Milk Fiber:
Milk protein fiber production line application processing system can not do without the cooperation of the link. Shanghai is home on R & D Technology Co., Ltd. milk silk protein fibers, also engaged in spinning, dyeing and finishing of technical research, raw material quality, technology is complete, customers can better support the promotion of milk fiber.

Milk protein fiber can be used, in theory, cationic dyes, direct dyes, acid dyes, reactive dyes, neutral dyes, generally more than the actual cationic dye and reactive dye used is suitable for pure milk protein fiber and its products, such as staple fiber, yarn line, knitted fabrics, woven fabrics and garments. Period in order to milk protein fiber textiles as an example of pure cationic dyes and reactive dyes on the usage described as follows.

Flow chart of milk fiber

After Treatment of Milk Fiber:
Cationic dyes and finishing the first treatment process, due to temperature and moisture absorption of the products are strong, so do not need special treatment. With 60 ?water, liquid running back 10s, and then the second can of cold wash. In the special white process, the use of prescription and bleaching conditions were as follows: 5% sodium hydrosulfite (95 ?with warm water even after accession); 5% of the standard soap powder (use warm water even after the accession), not alkaline , does not contain brighteners; bath ratio 1:20 ~ 30; temperature of 95 ~ 98 ? time is about 15s ~ 30s, but also according to liquor ratio, equipment and raw materials of different thickness to adjust. Note that, if so special white, raw materials without cooling; If the training is finished, then white, must be 2% to 3% of the HAC, 60 ?water running 5s ~ 10s, cold washed twice, and then softening. Prescription and use of the whitening process conditions: 1.6% cationic brighteners (Dilute with warm water even after accession); 3% HAC (Dilute with warm water even after accession); temperature of 95 ~ 98 ? time of 15s ~ 20s ; bath ratio 1:25 ~ 30. In the dyeing process, the basic cationic dye with the general approach, but not 1227, and NaAc. To liquor ratio 1:25 to 30, for example, dyeing conditions to control the following table. Cleaning, light to be 1 or 2 times the cold wash, cold wash in the dark to be 1 or 2 times and then wash with hot water, 70 ?10s, and finally cold wash 1 or 2 times. In the post-treatment processes, the use of softener 5% to 8%; temperature 45 ~ 50 ? time of 20s or so; bath ratio 1:20 ~ 25.

According to different requirements of customers can choose different softeners, such as the fabric soft, smooth, elastic anti-wrinkle, anti-contamination, etc. when requested, by the production units to decide. In the dehydration process, in order to reduce the discount video, dehydration, slower, time is shorter, usually 1 minute each time, while patients have to row together, try not to let cloth folded. In the drying process, the use of the cage drying temperature of 80 ? 5 ? time is 20s ~ 30s, speed too quickly, after drying grounds lit 12 to 24 hours after the stereotypes. Using rotary drying temperature of 90 ? 5 ? fast speed, the disadvantage is the easy bit like a very light, must be strictly controlled temperature.

In the setting process, the general shape of water rolling open sites, the effect is better than the cylindrical shape. Process parameters are 150 ? 5% overfeed of 10%, the line speed 15m / s, the pressure head of about 4kg. Reactive dyeing of basic aspects of pre-treatment with the former, but if the dye houses using recycled water, pH value may be unstable or reactive groups dealing with different materials, can be the first treatment bath by adding 1% of the HAC, it will give the pH value of the cloth evenly from the inside out, but also conducive to color dyes.

Proven, low temperature dyeing cotton used reactive dyes more suitable, light-colored soda instead of baking soda can be used as dyeing auxiliaries, the amount can be as long as required to achieve the color, the dark can be used for dyeing auxiliary sodium sulfate and soda ash , the amount of cotton fiber dyed with similar.

Uses of Milk or Casein Fiber:
Because of the healthy & bacteriostatic nature of milk Fiber, it is being considered as a perfect material for manufacturing of underwear. As discussed above, milk casein proteins are considered as a main ingredient of milk protein Fiber, which can lubricate the skin. The milk protein contains the natural humectant factor which can help to maintain the skin moisture, to reduce the wrinkles & to smoothen the skin - which may help to realize the people of taking milk bath.

The major usages of milk Fiber are as given below:

1. T-Shirts
2. Underwear
3. Sportswear
4. Ladies outerwear
5. Sweaters