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Tuesday 9 August 2011

Manufacturing Worsted Yarns | Manufacturing Woolen Yarns



Manufacturing Worsted Yarns: Now, we would learn the steps involved in manufacturing worsted yarns. In the manufacturer of worsted yarns, the Different steps involved are:

  • Carding

  • Gilling and combing

  • Drawing

  • Roving

  • Spinning




Carding: The carding process for worsted yarn production is intended to disentangle and lay them as parallel as possible. The fibres are passed between rollers covered with fine wire teeth. Since worsted yarns, however, should be smooth, the fibers are made to lie as parallel as this process will permit. Following this operation, the wool goes to the gilling and combing processes.

Gilling and Combing: Gilling is carried out before (preparative gilling) and after (finisher gilling) combing. The preparative gilling is mainly to align the fibers in a parallel direction, further blend the wool through doubling and to add moisture and lubricants. Whereas finisher gilling is mainly aimed to remove the mild entanglement introduced to the combed sliver. The carded wool, which is to be made into worsted yarn, is put through gilling and combing operations. The gilling process removes the shorter staple and straightens the longer fibers. This process is continued in the combing operation, which removes the shorter fibers of 1 to 4 inch (25 – 100 mm) lengths (called combing noils), places the longer fibers (called tops) as parallel as possible, and further cleans the fibers by removing any remaining loose impurities.

Drawing : Drawing is an advanced operation which doubles and redoubles slivers of wool fibers. The process draws, drafts, twists, and winds the stock, making the slivers more compact and thinning them into slubbers. Drawing is done only for worsted process.

Roving : This is the final stage before spinning. Roving is actually a light twisting operation to hold the thin slubbers intact.

Spinning : The type of spinning explained here is applicable both for woolen and worsted yarns. In the spinning operation, the wool roving is drawn out and twisted into yarn. There are two main methods used to produce woolen-spun yarns. These are:



  • Ring spinning

  • Mule spinning


Mule-spun yarns generally are superior to ring-spun yarns but they tend to be much more expensive due to the slow production rates and high labor input.

Worsted yarns are spun on any kind of spinning machine – mule, ring, cap, or flyer. The two principle systems of spinning worsted yarns are the English system and the French system.

· In the English system (Bradford), the fiber is oiled before combing, and a tight twist is inserted. This produces smoother and finer yarns. The more tightly twisted yarn makes stronger, more durable fabrics.

· In the French system, no oil is used. The yarn is given no twist; it is fuzzier, and therefore suitable for soft worsted yarns.

Manufacturing Woolen Yarns: In the manufacture of woolen yarns, the fibers are passed through two stages such as:

  • Carding

  • Spinning


The objective of carding process is to disentangle the fibers. In this process the wool fibers are passed between rollers covered with thousands of fine wire teeth. The wool fibers are disentangled by the action of the wires and are arranged in parallel fashion. This makes the woolen yarns smooth. Since the production of woolen yarns is intended to be rough or fuzzy, it is not desirable to have the fibers too parallel. By use of an oscillating device, one thin film, or sliver, of wool is placed diagonally and overlapping another sliver to give a crisscross effect to the fibers. This process helps in obtaining a fuzzy surface on the yarn.

The next stage is spinning which is similar to that of worsted production process. We would learn the spinning process is the next section.


Manufacturing Processes for Wool Based Yarns | Production Processes for Wool Yarns



Wool is the fiber derived from
the hair of domesticated animals, usually sheep. Wool is classified
according to the source from which it is obtained. The fleece or the
wool which is collected is kept to the different stages of manufacturing
process which starts with the preparation of the fiber. The different
stage through which it is taken depends upon whether the fiber is intended for worsted or woolen yarns. The flow chart for the manufacturing process is as follows:

Preparation Wool

Fleeces
vary from 6 to 18 pounds (3-8 kg) in weight. The best quality wool is
obtained from the sides and shoulders and is treated as one fleece.
Similarly, the wool obtained from the head, chest, belly, and shanks is
treated as a second fleece.






Preparation Wool


The
raw wool or newly sheared fleece is called grease wool because it
contains the natural oil of the sheep. When grease wool is washed, it
loses from 20 to 80 percent of its original weight. The wool obtained
should be carefully sorted into different grades.

Sorting and Grading: In
sorting, the wool is broken up into sections of different quality
fibers, from different parts of the body. The best quality of wool or
one fleece is used for clothing; the lesser quality or second fleece is
used to make rugs. Each grade is determined by type, length, fineness,
elasticity, and strength. The wool may be graded according to the type
of merino sheep or according to fineness or diameter which is otherwise
called as United States System and British System.

The
classification according to the United States System or according to the
type of merino sheep from which it is obtained is as follows:


  • First quality wool is identified as fine and is equivalent to the
    quality of wool that could be obtained from a full-to
    three-quarter-blood Merino sheep.

  • Second quality is equivalent to the kind of wool that could be obtained from a half blood Merino.

  • The
    poorest qualities are identified as common and braid; they are coarse,
    have little crimp, relatively few scales and are somewhat hair like in
    appearance.

  • The grading system on the world market is based upon
    the British numbering system, which relates the fineness, or diameter,
    of the wool fiber to the kind of combed, or worsted, yarn that could be
    spun from 1 pound of scoured wool.

  • The first in quality would be
    that wool which is fine enough for and capable of being spun into the
    highest wool yarn counts of 80s, 70s, and 64s (No. of 560 yards in 1 
    pound).

  •  The second quality is fine enough to be capable of being spun into yarn counts of 62s, 60s, and 58s.


  • The poorest grade is capable of being spun into yarn counts of only 40s and 30s.





TableComparative Wool Grading Table













United States System British System
Fine (full-to-three-quarter-blood) 80S, 70S, 64S
Half – blood 62S, 60S, 58S
Three – eights – blood 56S
Quarter – blood 50S, 48S
Low – quarter – blood 46S
Common 44S
Braid 40S, 36S






Scouring: Wool taken
directly from the sheep is called “raw” or “grease wool.” It contains
sand, dirt, grease, and dried sweat. The weight of these contaminants
accounts for about 30 to 70 percent of the fleece’s total weight.
Wool
scouring is the first step in the conversion of greasy wool into a
textile product. It is the process of washing wool in hot water and
detergent to remove the non-wool contaminants and then drying it. The
scouring machine contains warm water, soap and a mild solution of soda
ash or other alkali. They are equipped with automatic rakes, which stir
the wool. Rollers between the vats squeeze out the water. If the raw
wool is not sufficiently clear of vegetable substance after scoring, it
is put through the carbonizing bath of dilute sulfuric acid or
hydrochloric acid to burn out the foreign matter.

Drying: Wool
after scouring should not be allowed to become absolutely dry. About,
12 to16 percent of the moisture is left in the wool which would enable
handling of the fibers in further processing.

Oiling: Wool
is unmanageable after scouring and hence the fiber requires to be
treated with various oils to keep it from becoming brittle. Oiling of
the fibers also helps to lubricate it for the spinning operation.

Carding:
From this stage, further processing depends on whether woolen or
worsted yarns are to be produced. The main objective of carding is to
disentangle and to open the scoured wool. Carding also forms a web of
disentangled fibers that are formed into sliver.







Wool Fiber | Properties of Wool Fiber | Classification of Wool

Wool Fiber
Wool fiber is the natural hair grown on sheep and is composed of protein substance called as keratin. Wool is composed of carbon, hydrogen, nitrogen and this is the only animal fiber, which contains sulfur in addition. The wool fibers have crimps or curls, which create pockets and give the wool a spongy feel and create insulation for the wearer. The outside surface of the fiber consists of a series of serrated scales, which overlap each other much like the scales of a fish. Wool is the only fiber with such serration’s which make it possible for the fibers to cling together and produce felt.
Wool fiber
Properties of Wool Fiber
The characteristics of Wool fiber or protein fibers are as follows:
  • They are composed of amino acids.
  • They have excellent absorbency.
  • Moisture regain is high.
  • They tend to be warmer than others.
  • They have poor resistance to alkalis but good resistance to acids.
  • They have good elasticity and resiliency.
Classification of Wool
The quality of wool fibers produced is based on the breeding conditions, the weather, food, general care etc. For example, excessive moisture dries out natural grease. Similarly the cold weather produces harder and heavier fibers. The wool could be classified in two different ways:
  1. By sheep from which it is obtained
  2. By fleece
Classification by Sheep
The wool is classified according to the sheep from which it is sheared as given below:

Merino Wool: Merino sheep originated in Spain yields the best quality wool.
  • These fibers are strong, fine and elastic fiber which is relatively short, ranging from 1 to 5 inches (25 – 125 mm).
  • Among the different wool fibers, merino wool has the greatest amount of crimp and has maximum number of scales. These two factors contribute to its superior warmth and spinning qualities.
  • Merino is used for the best types of wool clothing.
Class – Two Wool: This class of sheep originates from England, Scotland, Ireland and Wales.
  • The fibers are comparatively strong, fine, and elastic and range from 2 to 8 inches (50 – 200mm) in length.
  • They have a large number of scales per inch and have good crimp.
Class – Three Wool: This class of sheep originates from United Kingdom.
  • The fibers are coarser and have fewer scales and less crimp when compared to earlier varieties of wool fibers and are about 4 to 18 inches long.
  • They are smoother, and are more lustrous.
  • These wool are less elastic and resilient.
  • They are of good quality, used for clothing.
Class – Four Wool: This class is a group of mongrel sheep sometimes referred to as half-breeds.
  • The fibers are abour 1 to 16 inches (25 – 400 mm) long, are coarse and hair like, and have relatively few scales and little crimp.
  • The fibers are smoother and more lustrous.
  • This wool is less desirable, with the least elasticity and strength. It is used mainly for carpets, rugs, and inexpensive low-grade clothing.
Classification by Fleece
Shearing, is the process by which the woolen fleece of a sheep is removed. Sheep are generally shorn of their fleeces in the spring, but the time of shearing varies in different parts of the world. Sheep are not washed before shearing. They are sometimes dipped into an antiseptic bath as prescribed by law. The classification by fleece is as follows:

Lamb’s Wool: The fleece obtained by shearing the lamb of six to eight months old for the first time is known as lamb’s wool. It is also referred to as fleece wool, or first clip. As the fiber has not been cut, it has a natural, tapered end that gives it a softer feel.

Hogget Wool: Hogget wool is the one obtained from sheep about twelve to fourteen months old that have not been previously shorn. The fiber is fine, soft, resilient, and mature, and has tapered ends. These are primarily used for warp yarns.

Wether Wool: Wether wool is the one obtained from the sheep older than fourteen months. The shearing is not done for the first time and in fact these fleeces are obtained after the first shearing. These fleeces contain much soil and dirt.

Pulled Wool: Pulled wool is taken from animals originally slaughtered for meat. The wool is pulled from the pelt of the slaughtered sheep using various chemicals. The fibers of pulled wool are of low quality and produce a low-grade cloth.

Dead Wool: This is the wool obtained from the sheep that have died of age or accidentally killed. This type of wool fiber known should not be confused for pulled wool. Dead wool fiber is decidedly inferior in grade; it is used in low-grade cloth.

Cotty Wool: This type of wool is obtained from the sheep that are exposed to severe weather. As discussed; the severe weather conditions hamper the qualities of the fleece obtained. The cotty wool is of a poor grade and is hard and brittle.

Tag locks: The torn, ragged, or discolored parts of a fleece are known as tag locks. These are usually sold separately as an inferior grade of wool.

Sunday 7 August 2011

Properties of Size Ingredients | Size Ingredients and Their Functions


Size ia a coating with a gelatinous or other substance to add strength or stiffness or to reduce absorbency.Sizing is the process of applying the size material on yarn.

Properties of Size Ingredients 
  • Ease of preparation 
  • Uniform viscosity 
  • Absence of prolonged congealing and kenning at application temperature 
  • pH control 
  • absence of foaming properties 
  • absence of prolonged tackiness 
  • compatibility with other components of the size 
  • stability towards decomposition 
  • ease of desizing
Size Ingredients and their functions 

Adhesive: example: maize, wheat, corn, potato, ferina, sago, PVC, PVA, CMC
Function: it increases yarn strength and abrasion resistance

Lubricant: example: mineral oil, linseed oil, tallow, Japan was, cotton oil
Function: increases yarn smoothness and elasticity

Antiseptic agent: example: ZnCl2 , Phenol, carboxylic acid, synthetic acid
Function: it helps to store the yarn without being damaged and it also gives protection from bacteria or fungus.

Deliquescent agent: example: MgCl2, glycerin
Function: it prevents brittleness of size and helps to keep the standard moisture regain by not allowing water to enter or exit the fibre.

Weighting agent: example: china clay, French chalk
Function: it increases the weight of the yarn

Wetting agent: example: MgCl2
Function: helps to wet the yarn instantaneously

Tinting agent: example: Blue
Function: it helps o increase the brightness of yarn

Antifoaming agent: example: Benzene, Pyridine
Function: it prevents the formation of foam

Define Sizing | Objects of Sizing | Types of sizing | Properties of Size Ingredients | Disadvantages of Sizing

Sizing:
Size is a gelatinous film forming substance in solution or dispersion form, applied normally to warp yarns. It can sometimes be applied to weft yarns. Sizing is the process of applying the size material on yarn.A generic term for compounds that are applied to warp yarn to bind the fiber together and stiffen the yarn to provide abrasion resistance during weaving. Starch, gelatin, oil, wax, and manufactured polymers such as polyvinyl alcohol, polystyrene, polyacrylic acid, and polyacetates are employed. 2. The process of applying sizing compounds. 3. The process of weighing sample lengths of yarn to determine the count. Now automation is used in sizing operation.
Yarn sizing
Objects of Sizing:
  1. To protect the yarn from abrasion
  2. To improve the breaking strength of the yarn
  3. To increase smoothness of yarn
  4. To increase yarn elasticity
  5. To decrease hairiness
  6. To decrease the generation of static electricity
Types of Sizing:
  1. Pure sizing: when the size pick up % is about 3 – 10 % it is called pure sizing.
  2. Light sizing: when the size pick up % is about 11 -16% it is called light sizing.
  3. Medium sizing: when the size pick up % is about 17 – 40 % it is called medium sizing.
  4. Heavy sizing: when the size pick up % is above 40 % then it is called heavy sizing.
Disadvantages of Sizing:
  • Cost of land and machine is high
  • Requires lot of labors
  • Requires utility like gas, electricity etc and their cost is high
  • Cost of ingredients
  • The process is long and it takes time
  • There is a risk of degradation of yarn
  • The yarn diameter is increased
  • Requires robust loom
  • It increases yarn stiffness
  • The fabric needs to be desized before use
  • Need knowledge and information about the size ingredients
  • There is a risk of pollution
  • Sizing changes the shade of colored yarn
  • 100% size material cannot be removed
  • Size material presence leads to uneven dying
 

Warping Machine | Main Parts of Warping Machine | Components of Creel | Components of Headstock

Warping:
The operation of winding warp yarns onto a beam usually in preparation for slashing, weaving, or warp knitting. Also called warping. In a word, Warping is the parallel winding of yarn from cone or cheese package on to a warp beam. Warping Process are done by different types of Warping Machine. The main parts of warping machine are given below.
Warping Machine
Components of a Warping Machine
The warping machine is mainly divided into two major components
  1. Creel
  2. Headstock
Components of Creel
  • yarn clearer
  • stop device
  • indicator
  • tensioners
  • yarn guide
  • package base
  • blower or suction fan
Components of Headstock
  • adjustable V-wraith
  • measuring and marking device
  • yarn speed controlling device
  • pneumatic or hydraulic pressure unit
  • break assembly
  • driving drum
  • stop motion
  • building drum
  • beam bracket
  • lease rod
 

Yarn Tensioners in Weaving | Types of Tensioning Device | Important Effects of Tensioning Device | Factors Influencing the Selection of Tensioners

Yarn Tensioners:
Yarn Tensioners are devices by the help of which tension is given to the yarn. This is an important device because it enables us to provide necessary tension to the yarn as it moves through the different parts of the mschine. It is specially used in spinning, weaving and knitting machine.
Yarn Tensioners
Types of tensioning device 
There are basically three types of method by which tension is applied to yarn. They are as follows:
  • Capstan method 
  • Additive method 
  • Combined method
Capstan Method
This is the simplest form of yarn tensioning device where the yarn is passed around posts where the tension on the yarn is provided from the friction between the posts and yarns.

This follows the classic law of:

Output tension = Input tension x eµθ


Additive method
In this method the yarn is passed through the middle of two surfaces in contact. The force is applied from above to give suitable tension to the yarn.

Combined method
The combined system is a combination of capstan and additive method. This device is a complicated system which on allows the addition of tension. We cannot decrease the tension with this device. It is seldom used.

Important effects of tensioning device 
If the tension is too high then
  • The yarn can be damaged 
  • The rate of yarn breakage will be high 
  • The elongation property of yarn will change
If the tension is too low then
  • It can lead to unstable or loose package formation which will cause problems during unwinding
  • Variation in yarn in different parts of a wound package will cause undesirable effects
For man made filament yarn improper tension will cause
  • Change in molecular structure 
  • Variation in colour shades
For staple or spun yarn too high tension will cause
  • Yarn breakage at thin places
Factors influencing the selection of Tensioners 
  • The device must be reliable to control uniform tension 
  • The device must be easily thread able 
  • It must not introduce or magnify tension variation 
  • It must not introduce variation in twist 
  • It must not be affected by wear 
  • It must be easily adjustable 
  • It must not be affected by oil and dirt 
  • It must not encourage dirt collection 
  • It must be easily cleanable 
  • The operating surface must be smooth 
  • It must be cheap
 

Yarn Clearer in Winding | Types of Yarn Clearer | Comprise Between Mechanical and Electronic Clearer

Yarn Clearer 
Yarn clearer is the device which is used to remove the following faults of yarn in order to increase the yarn quality and weaving efficiency.

Faults of yarn are as follows
  • Thick and thin places 
  • Slab and neps 
  • Loose fabric 
  • Foreign materials
Types of Yarn Clearer

There are two types of yarn clearer

1. Mechanical Type

a. Conventional blunt type
b. Serrated blade type

2. Electronic type

a. Capacitance type
b. Photo electric type

Comprise between mechanical and electronic clearer

• Electronic clearer are more sensitive than mechanical clearers
• In case of mechanical clearers there is abrasion between yarn and clearer parts but in case of electronic clearers there is no such abrasion
• Mechanical clearers do not prevent soft slab from escaping through clearer where as electronic type does not allow passing of any types of faults
• Mechanical type does not break the thin places and the length of the fault is not considered
• Mechanical clearer are simple and easy to maintain while the electronic clearers are costly and requires high standard of maintenance


Yarn Winding process | Precision Winding | Non Precision Winding

Winding is the process of transferring yarn or thread from one type of package to another to facilitate subsequent processing. The rehandling of yarn is an integral part of the fiber and textile industries. Not only must the package and the yarn itself be suitable for processing on the next machine in the production process,
but also other factors such as packing cases, pressure due to windingtension, etc., must be considered. Basically, there are two types of winding machines: precision winders and drum winders. Precision widers, used primarily for filament yarn, have a traverse driven by acam that is synchronized with the spindle and produce packages with a diamond-patterned wind. Drum winders are used principally for spun yarns; the package is driven by frictional contact between the surface of the package and the drum.

Types of Winding
A.Precision Winding
B.Non Precision Winding 

A.Precision Winding 
By precision winding successive coils of yarn are laid close together in a parallel or near parallel manner. By this process it is possible to produce very dense package with maximum amount of yarn stored in a given volume.

Features 
  • Package are wound with a reciprocating traverse 
  • Patterning and rubbing causes damage of packages 
  • Package contains more yarn 
  • Package is less stable 
  • The package is hard and compact 
  • The package is dense 
  • Rate of unwinding of package is low and the process of unwinding is hard 
  • The unwound coil is arranged in a parallel or near parallel manner

B.Non Precision Winding 
By this type of winding the package is formed by a single thread which is laid on the package at appreciable helix angle so that the layers cross one another and give stability to the package. The packages formed by this type of winding are less dense but is more stable.

Features
  • Only one coil is used to make this packages 
  • Cross winding technique is used 
  • The package density is low 
  • Minimum number of yarn is wound 
  • The package formed is soft and less compact 
  • The stability is high 
  • Flanges are not required 
  • The rate of unwinding is high and the process is easy 
  • The packages formed have low density

Saturday 6 August 2011

Winding Efficiency | Factors of Winding Efficiency | Reasons for Lower Efficiency

Winding Efficiency :   The ratio of actual production and calculated production is called winding efficiency. It is expressed  as percentage. The efficiency of a highly automated winding operation is calculated by modification of the mathematical model developed for a similar problem.





Winding efficiency depends on the following factors 
  • Spindle or drum speed: the higher the speed the more is the winding efficiency
  • Yarn Count: yarn count is proportional to winding efficiency
  • Yarn quality: if yarn quality increases then winding efficiency increases
  • Worker efficiency: the more efficient the work is the more efficient the winding will be.
  • Humidity: humidity is reciprocal or inversely proportional to winding efficiency.
  • Work load per worker: If the work load on each worker is less then efficiency of winding will be more.
  • Maintenance and over hauling: if the maintenance and over hauling of the machine is not correct then efficiency of winding will decrease.
  • Power failure: if power failure rate increases the winding efficiency will decrease.
  • Creeling time: the more the creeling time the less is the efficiency.
  • Doffing time: the more the doffing time the less is the efficiency.
  • Capacity utilization: when capacity utilization decreases then efficiency increases.
Reasons for lower efficiency 
  • power failure
  • improper maintenance and over hauling
  • natural disasters
  • less skilled labor
  • labor unrest
  • shortage of machine parts and raw materials
  • strike
  • maintenance problems


Winding Packages | Types of Winding Packages | Parallel Winding | Non Parallel Winding | Cross Winding

The process of transferring yarn from small packages like hank, bobbing etc to a large package such as cones, pirns, cheese etc, containing considerable length of yarn is called winding. The suitable package is used for proper winding are called winding package. 

Types of Winding Packages 
  • Parallel Winding 
  • Non Parallel Winding 
  • Cross Winding
Parallel Winding Package

In this type of winding the yarn is wound parallel to each other on package containing flanges on both sides. This type of winding does not require traversing guide.

Advantages of parallel winding

• many yarns can be wound at the same time
• no need of traversing guide
• no change in yarn twist occurs
• the package is stable
• side withdrawal is possible

Disadvantages of parallel winding
  • flanges are required 
  • separate mechanism is required to unwind the yarn 
  • over withdrawal is not possible
example: beam, flange

Non parallel Winding Package

This package contains one or more threads which are laid very nearly parallel to the layers already existing on the package.

Advantage of non parallel winding
  • flanges are not required 
  • over withdrawal is possible 
  • no change in yarn twist occurs
Disadvantages of non parallel winding
  • side withdrawal is not possible 
  • the package is not stable 
  • traversing machine is required
example: cop

Cross Winding Package

This type of package contains a single thread which is laid on the package at an appreciable helix angle so that the layers cross one another to give stability.

Advantages of cross winding
  • flange is not required 
  • yarn package is very stable 
  • over withdrawal is possible
Disadvantage of cross winding
  • the yarn twist is changed during this winding 
  • traversing mechanism is required

Process Flow Chart of Weaving

Different fabrics are produced In Weaving Industry. These fabrics are weaved by using various looms and related machines. Before going straightly to the Weaving process; some pretreatment and pre-process should be carried out. See these below : -

Process Flow Chart of Weaving 


Process Flow Chart of Weaving 




Friday 5 August 2011

What is Modacrylic fiber | Properties of Modacrylic Fiber | Uses of Modacrylic Fiber | Application of Modacrylic Fiber

Modacrylic fiber
Modacrylic fiber is a manufactured fiber in which the fiberforming substance is any long chain synthetic polymer composed of less than 85% but at least 35% by weight of acrylonitrile units. (-CH2CH[CN]-)x. A modacrylic is a synthetic copolymer. Modacrylic fiber is inherently flame resistant. Although it burns when directly exposed to flame, it doesn’t melt or drip and is self-extinguishing when the flame is removed. Modacrylic is widely used in high performance protective clothing, such as firefighting turnout gear, because flame resistance is combined with other desirable textile properties such as durability and good hand feel. Modacrylics are soft, strong, resilient, and dimensionally stable. They can be easily dyed, show good press and shape retention, and are quick to dry. They have outstanding resistance to chemicals and solvents, are not attacked by moths or mildew, and are nonallergenic. Among their uses are in apparel linings, furlike outerwear, paint-roller covers, scatter rugs, carpets, and work clothing and as hair in wigs.

Modacrylic fiber is chemical resistant. It retains its strength in concentrated acid/alkaline environments, which is useful for certain types of industrial filtration. Modacrylic is also on the extreme negative end of the triboelectric scale, and when combined with another more positive fiber such as polypropylene, results in a triboelectric media with improved filtration efficiency.

Modacrylic fibers are made from resins that are copolymers (combinations) of acrylonitrile and other materials, such as vinyl chloride, vinylidene chloride or vinyl bromide. Modacrylic fibers are either dry spun or wet spun.

Characteristics of Modacrylic Fiber 
  • Soft 
  • Resilient 
  • Easy to dye to bright shades 
  • Abrasion resistant 
  • Flame resistant 
  • Quick drying 
  • Resistant to acids and alkalies 
  • Shape retentive
The low softening temperatures of modacrylic fibers allow them to be stretched, embossed and molded into special shapes. The fibers may be produced with controlled heat shrinkage capacities. When fibers of different shrinkages are mixed in the surface of a pile fabric, the application of heat develops fibers of different lengths, producing a surface that resembles natural fur.

Properties of Modacrylic Fiber



General Properties

Chemistry
35% acrylonitrile / 65% vinylidene chloride

Size
3 denier x 51mm cut length

Crimp Level
3.8 crimps/cm

Moisture
3.5% (typical)

Thermal Properties
LOI

28 to 32
Mechanical Properties

Strength
2.6 cN/den (dry)

Elongation
28% (dry)




Application of Modacrylic Fiber

Apparel: Deep-pile coats, trims and linings, simulated fur, wigs and hair pieces, children’s sleepwear, career apparel 

Fabric: Fleece, knit-pile fabric backings, nonwovens 

Home Furnishings: Awnings, blankets, carpets, flame-resistant draperies and curtains, scatter rugs 

Other Uses: Filters, industrial fabrics, paint rollers, stuffed toys.

Precaution for Modacrylic Fiber

Dry-cleaning or fur-cleaning process is suggested for deep-pile garments. For washable items:
  • Machine wash in warm water and add fabric softener during the final rinse cycle. 
  • If dryer is used, use low setting and remove articles as soon as tumbling cycle has stopped. 
  • If ironing is required, use low setting. Never use a hot iron. (For specific instructions, refer to garment’s sewn-in care label.) 


What is Elastoester Fiber | Properties of Elastoester Fiber | Uses of Elastoester Fiber


Elastoester is an official FTC generic fiber type defined as: At least 50% by weight aliphatic polyether and at least 35% by weight polyester. Elastoester is similar to polyester, but different enough physically to warrant a new generic name under the FTC’s Textile Labeling Rules. According to a notice the FTC placed in today’s Federal Register, elastoester is stretchy like spandex, readily washable, and can withstand high temperatures when wet. As a result, it retains dyes better than fabrics made of nylon and spandex and is less likely to be discolored or adversely affected by chlorine, an important characteristic for swimming suits.

Characteristics of Elastoester Fiber
  • Possesses polyester-like qualities. 
  • Excellent elongation qualities (stretchability). 
  • Washable/easy care. 
  • Can withstand high temperatures when wet. 
  • Excellent dye retention. 
  • No adverse discoloring or yellowing when exposed to chlorine. 
Uses of Elastoester Fiber

Apparel - 
  • sweaters,
  • hosiery and socks
  • foundation garments, 
  • knitwear, 
  • dresses, 
  • swimwear, 
  • activewear, 
  • athletic wear, 
  • ski pants,
Sportswear-
  • swimsuits, 
  • cycling shorts and 
  • ski pants.

Melamine Fiber | Properties of Melamine Fiber | Manufacturing Process of Melamine Fiber | Applications of Melamine Fiber | Uses of Melamine Fiber

Melamine fiber is a manufactured fiber in which the fiber-forming substance is a synthetic polymer composed of at least 50% by weight of a cross-linked melamine polymer. Melamine fiber is a cost effective heat resistant fiber based on melamine chemistry, with a 400°F (200°C) continuous operating temperature. Melamine fibers are flame resistant, have outstanding heat/dimensional stability, and are self-extinguishing. EFT’s WF series of melamine fibers have a fiber length distribution tailored for use in wet-laid nonwovens. Typical fiber lengths are in the 1-12mm range, and they show excellent dispersion and formation in wet-laid processes. 

Flame Resistance of Melamine Fiber




Characteristics of Melamine Fiber 
  • Chars without shrinking 
  • Naturally flame retardant 
  • Low thermal conductivity 
  • Non-toxic / No VOC release
  • White and dyeable 
  • Flame resistance and low thermal conductivity 
  • High heat dimensional stability 
  • Processable on standard textile equipment
Typical Properties of Melamine Fiber

Measurement

Units
Typical Values

Color
Ivory white

Average Diameter
µm

15
Average Denier

g/9000m
2.4

Specific Gravity
1.4

Tensile Strength
ksi

36
Tenacity

g/den
2.0

Modulus
Msi
g/den

1.0
55
Elongation at Break

%
11

Moisture Regain (23°C, 65% RH)
%

5
Shrinkage at 200°C (1hr exposure)

%
Limiting Oxygen Index

%
32

Maximum Continuous Operating Temperature
°C

200
Melting Temperature

°C
Does not melt or drip

Resistance to Mildew, Aging, Sunlight
Excellent

Resistance to Solvents, Alkalis
Excellent



Production Process of Melamine Fiber

The production process is proprietary. It is based on a unique melamine chemistry that results in a cross-linked, non-thermoplastic polymer of melamine units joined by methylene and dimethylene ether linkages. In the polymerization reaction, methylol derivatives of melamine react with each other to form a three-dimensional structure. This structure is the basis for the fiber’s heat stability, solvent resistance, and flame resistance.

Applications of Melamine Fiber
  • Mattresses, Home Furnishings / Nonwovens
  • (Compliant with 16CFR1633)
  • Specialty flame resistant papers
  • Firefighting apparel
  • Electrical papers
  • Transmission / friction papers
  • Filtration media
  • Engineered materials / Short-fiber composites
  • Adhesives / Fillers
  • Tire sealants
  • Truck / Rail brakes
Besides Melamine fiber has Potential use which are given below :

Fire Blocking Fabrics: Aircraft seating, fire blockers for upholstered furniture in high-risk occupancies (e.g., to meet California TB 133 requirements)

Protective Clothing: Firefighters’ turnout gear, insulating thermal liners, knit hoods, molten metal splash apparel, heat resistant gloves.

Filter Media: High capacity, high efficiency, high temperature baghouse air filters.



Thursday 4 August 2011

Aramid Fiber | Manufacturing Process of Aramid | Properties of Aramid Fiber | Uses of Aramid Fiber | History of Aramid Fiber

Aramid Fiber:
Aramid ia a manufactured fiber in which the fiberforming substance is a long-chain synthetic polyamide in which at least 85% of the amide (-CO-NH-) linkages are attached directly between two aromatic rings.

Technically, aramid fibers are long-chain synthetic polyamides. Aramid fibers have extremely high tensile strength, which is why they are commonly used in armor and ballistic protection applications. With a distinctive yellow color, aramid fibers are frequently used in advanced composite products which require high-strength and light-weight properties.

Structure of Aramid
Also Known As: Kevlar (Trademark of DuPont), Twaron (Trademark of Teijin)

History of Aramid Fiber | Aramid Fiber History
Aromatic polyamides were first introduced in commercial applications in the early 1960s, with a meta-aramid fiber produced by DuPont under the tradename Nomex. Aramid fiber, which handles similarly to normal textile apparel fibers, is characterized by its excellent resistance to heat, as it neither melts nor ignites in normal levels of oxygen. Aramid is used extensively in the production of protective apparel, air filtration, thermal and electrical insulation as well as a substitute for asbestos. Meta-aramid is also produced in the Netherlands and Japan by Teijin under the tradename Teijinconex, in China by Yantai under the tradename New Star and a variant of meta-aramid in France by Kermel under the tradename Kermel.

Manufacturing Process of Aramid
World capacity of para-aramid production is estimated at about 41,000 tons/yr in 2002 and increases each year by 5-10%. In 2007 this means a total production capacity of around 55,000 tons/yr.

Spinning:
After production of the polymer, the aramid fiber is produced by spinning the solved polymer to a solid fiber from a liquid chemical blend. Polymer solvent for spinning PPTA is generally 100% (water free) sulfuric acid (H2SO4).

Appearances of Aramid Fiber
  • Fiber
  • Chopped fiber
  • Powder
  • Pulp
Aramid Fiber Characteristics
  • Good resistance to abrasion
  • Good resistance to organic solvents
  • Nonconductive
  • No melting point, degradation starts from 500°C
  • Low flammability
  • Good fabric integrity at elevated
  • Sensitive to acids and salts
  • Sensitive to ultraviolet radiation
  • Prone to static build-up unless finished
Uses of Aramid Fiber
  • Flame-resistant clothing
  • Heat protective clothing and helmets
  • Body armor[competing with PE based fiber products such as Dyneema and Spectra
  • Composite materials
  • Asbestos replacement (e.g. braking pads)
  • Hot air filtration fabrics
  • Tires, newly as Sulfron (sulfur modified Twaron)
  • Mechanical rubber goods reinforcement
  • Ropes and cables
  • Wicks for fire dancing
  • Optical fiber cable systems
  • Sail cloth (not necessarily racing boat sails)
  • Sporting goods
  • Drumheads
  • Wind instrument reeds, such as the Fibracell brand
  • Speaker woofers
  • Boathull material
  • Fiber reinforced concrete
  • Reinforced thermoplastic pipes
  • Tennis strings (e.g. by Ashaway and Prince tennis companies)
  • Hockey sticks (normally in composition with such materials as wood and carbon) 
 

What is Spandex Fiber | Properties of Spandex Fiber | Production Process of Spandex Fiber | Manufacturing Process of Spandex Fiber | Uses of Spandex Fiber

Spandex is a manufactured fiber in which the fiber forming substance is a long-chain synthetic polymer comprised of at least 85% of a segmented polyurethane. Spandex or elastane is a synthetic fiber known for its exceptional elasticity (stretchability). It is stronger and more durable than rubber
, its major plant competitor. It was invented in 1959, and when first introduced it revolutionized many areas of the clothing industry.Spandex is the preferred name in North America, while elastane is most often used elsewhere. A well-known trademark for spandex or elastane is Invista’s brand name Lycra; another trademark (also Invista’s) is Elaspan.

Characteristics of Spandex Fiber 
  • Can be stretched repeatedly and still recover to very near its original length and shape 
  • Generally, can be stretched more than 500% without breaking 
  • Stronger, more durable and higher retractive force than rubber 
  • Lightweight, soft, smooth, supple 
  • In garments, provides a combination of comfort and fit, prevents bagging and sagging 
  • Heat-settable — facilitates transforming puckered fabrics into flat fabrics, or flat fabrics into permanent rounded shapes 
  • Dyeable 
  • Resistant to deterioration by body oils, perspiration, lotions or detergents 
  • Abrasion resistant 
  • When fabrics containing spandex are sewn, the needle causes little or no damage from “needle cutting” compared to the older types of elastic materials 
  • Available in fiber diameters ranging from 10 denier to 2500 denier 
  • Available in clear and opaque lusters.
Spandex Fiber Production 

The polymer chain is a segmented block copolymer containing long, randomly coiled, liquid, soft segments that move to a more linear, lower entropy, structure. The hard segments act as “virtual cross-links” that tie all the polymer chains together into an infinite network. This network prevents the polymer chains from slipping past each other and taking on a permanent set or draw. When the stretching force is removed, the linear, low entropy, soft segments move back to the preferred randomly coiled, higher entropy state, causing the fiber to recover to its original shape and length. This segmented block copolymer is formed in a multi-step proprietary process. It is extruded into a fiber as a monofilament threadline or for most products into a multiplicity of fine filaments that are coalesced shortly after they are formed into a single threadline.

Uses of Spandex Fiber 

Garments where comfort and fit are desired: hosiery, swimsuits, aerobic/exercise wear, ski pants, golf jackets, disposable diaper, waist bands, bra straps and bra side panels. 

Compression garments: Surgical hose, support hose, bicycle pants, foundation garments 

Shaped garments: Bra cups


Flax Fiber | Properties of Flax Fiber | Histroy of Flax Fiber | Applications of Flax Fiber | Uses of Flax Fiber

Flax is also called Linen. The fibre is obtained from the stalk of a plant (Linum Usitatissimum - A literal translation is “linen most useful.” ) which is from 80 to 120 cm high, with few branches and small flowers, of a colour which varies from white to intense blue, which flowers only for one day. Common flax was one of the first crops domesticated by man. 

Flax is thought to have originated in the Mediterranean region of Europe; the Swiss Lake Dweller People of the Stone Age apparently produced flax utilizing the fiber as well as the seed. Linen cloth made from flax was used to wrap the mummies in the early Egyptian tombs. In the United States, the early colonists grew small fields of flax for home use, and commercial production of fiber flax began in 1753. However, with the invention of the cotton gin in 1793, flax production began to decline. Presently the major fiber flax producing countries are the Soviet Union, Poland, and France.

Common flax (also known as linseed) is a member of the Linaceae family which includes about 150 plant species widely distributed around the world. Some of them are grown in domestic flower beds, as flax is one of the few true blue flowers. Most “blue” flowers are really a shade of purple.

Properties of Flax Fiber

70% is composed of cellulose, it cannot provoke allergies, absorbs humidity and allows the skin to breathe: therefore it is very indicated in the manufacture of summer articles. Very resistant, above all if wetted it can be washed many times without alteration, rather it becomes softer, something very important for articles of clothing and for daily use which require frequent washing such as shirts. Having very low elasticity, linen cloths do not deform themselves. 

European linen fabrics today are luxurious, elegant, comfortable and practical. Linen is thermo regulating, non-allergenic, antistatic and antibacterial. Because it can absorb up to 20 times its weight in moisture before it feels damp, linen feels cool and dry to the touch. It is not by accident that the world’s oldest and most useful fiber is still in great demand.

Flax History | Histroy of Flax Fiber

Flax fibres are amongst the oldest fibre crops in the world and the use of flax for the production of linen goes back 5000 years. Pictures on tombs and temple walls at Thebes depict flowering flax plants. The use of flax fibre in the manufacturing of cloth in Northern Europe dates back to pre-Roman times. In the USA flax was introduced by the Pilgrim fathers. Currently all flax produced in the USA and Canada are seed flax types for the production of linseed oil or flaxseeds for human nutrition.Flax fibre is soft, lustrous and flexible. It is stronger than cotton fibre but less elastic. The best grades are used for linen fabrics such as damasks, lace and sheeting. Coarser grades are used for the manufacturing of twine and rope. Flax fibre is also a raw material for the high quality paper industry for the use of printed currency notes and cigarette paper.

The major fibre flax producing countries are the former USSR, Poland, France, Belgium and the Czech Republic

Applications of Flax Fiber
  • Table wear 
  • Suiting 
  • Clothing apparel 
  • Surgical thread 
  • Sewing thread 
  • Decorative fabrics 
  • Bed linen 
  • Kitchen towels 
  • High quality papers 
  • Handkerchief linen 
  • Shirting 
  • Upholstery 
  • Draperies 
  • Wall coverings 
  • Artist’s canvases 
  • Luggage fabrics 
  • Paneling 
  • Insulation 
  • Filtration 
  • Fabrics for light aviation use 
  • Automotive end uses 
  • Reinforce plastics and composite materials. 
  • Flax could conceivably be mixed with excess grass seed straw or softwood fiber in composite boards 
Consumers around the world buy linen because they like the way it looks, feels and performs. With new varieties of flax; new processing techniques; and new ways of spinning, weaving and finishing, the European linen industry has reinvented itself. And all of the links in the supply chain are working together through the European flax and linen organization, Masters of Linen, Paris, to market linen globally to a new and growing trade of niche players.

The flax plant has also a couple of other important end uses 

Industrial Uses:
Flax is still produced for its oil rich seed. Linseed oil has been used as a drying agent for paints, varnishes, lacquer, and printing ink. Unfortunately these markets have eroded somewhat over the years with the production of synthetic resins and latex. One bright spot in the market has been the use of linseed oil as an anti-spalling treatment for concrete where freezing and thawing effects have created problems on streets and sidewalks. Occasionally the straw is harvested and used to produce some paper products. 

Livestock Feed:
Linseed oil meal is an excellent protein source for livestock containing about 35% crude protein. Flax straw on the other hand, makes a very poor quality forage because of its high cellulose and lignin content. 

Human Food:
Recently there has been some interest in seed flax as a health food because of its high amount of polyunsaturated fatty acids in the oil.