October 2017 - Textile Study365

Archive for October 2017

Some Impotent Trams About Water Which Is Used In Textile Wet Processing?

October 14, 2017 কোন মন্তব্য নেই water

##Why water is called universal solvent?

Water is called universal solvent, because the solvency power of water is very high & most of the solute of this world is easily dissolved in the water.

##What do you mean by water hardness?

Hardness is a term applied to water denoting a measurement of its pH & metal salt content. The presence of Ca & Mg salt i.e. Bi-Carbonates, Sulfates, Chlorides in water is called causes of hardness of water. The water which contains these salts is called hard water. Hard water does not easily form lather with soap as the salt of Ca & Mg react with soap to form insoluble organic salts.

CaSO4 + 2 RCOONa → (RCOO)2Ca ↓ + Na2SO4.

MgSO4 + 2 RCOONa → (RCOO)2Mg ↓ + Na2SO4.

##State different types of water hardness?

Water hardness may be classified into following two types-

1) TEMPORARY HARDNESS:

Temporary hardness is due to the presence of Bi-Carbonates of Ca & Mg. this type of hardness is called temporary hardness, because, it can be removed by easy means like boiling. When temporary hard water is boiled, the Carbonates decompose with liberation of CO2 & precipitation of the insoluble Carbonates which are reformed.

Ca(HCO3)2 ∆→ CaCO3↓ + CO2 + H2O Mg(HCO3)2 ∆→ MgCO3 ↓ + CO2 + H2O

2) PERMANENT HARDNESS:

It is due to the presence of Sulfates, Chlorides of Ca & Mg. this type of hard water is called permanent hardness. These salts do not decompose on boiling. So, permanent hardness cannot be removed.

##Write down the name of mineral metallic salts which is responsible for water hardness?

The name of mineral metallic salts which is responsible for water hardness-

1. Ca(OH)2;

2. Mg(HCO3)2;

3. Al(HCO3)2;

4. Fe(HCO3)2;

5. CaSO4;

6. MgSO4;

7. Al2(SO4)3;

8. FeSO4;

9. CaCl2;

10. MgCl2;

11. AlCl2;

12. FeCl2.

##Why soap does not create foam easily with hard water? Explain with reaction?

Soap does not create foam easily with hard water as the salt of Ca & Mg react with soap to form insoluble organic salts.

CaSO4 + 2 RCOONa → (RCOO)2Ca ↓ + Na2SO4.

MgSO4 + 2 RCOONa → (RCOO)2Mg ↓ + Na2SO4.

Define water? Classification of water?

October 14, 2017 কোন মন্তব্য নেই water

Water:

Water is a complex compound. It is very important compound in textile wet processing. The total amount of water in the world is about 75%. Natural water is obtained in 3 steps. They are solid, liquid & vapor. Water has a un-comparable power to dissolve other compound. It is very difficult to obtain pure water in nature. Water is consists of two part Hydrogen & one part Oxygen. Its chemical formula is H2O. Water is converted to ice at 0°C & converted to vapor at 100°C the concentration of water is highest at 4°C.

Classification of water:

Classify water on the basis of hardness:

DESCRIPTION	TOTAL HARDNESS (degree)
Very soft	0 - 4°
Soft	5 - 8°
Mild	9 - 14°
Fairly mild	15 - 18°
Hard	19 - 30°
Very hard	>30°

Classify water on the basis of source:

On the basis of source water may be classified into followings-

1) RAIN WATER:

Rain, collected immediately after recitation, is the purest of all natural water.
It may contain traces of gases dissolved out of the atmosphere & possibly an almost infinitely small amount of finely divided solid matter derived from the air.
It also contain dissolved or Sulfur DI-oxide or Sulfuric acid, CO2, NH3, NO2 & other by products of industrialization.
Suspended impurities present in it, can be filtered by using sand bed.
Suitable for boiling, washing & dyeing process.

2) SURFACE WATER:

Surface water may consists of rain water which has collected from streams, rivers or lakes.
This type of water contains organic & inorganic matters which are dissolved in it
& also contain suspended impurities.
Then the nutrifying bacteria will in time convert the organic substances into nitrates which are not objectionable in dyeing & printing.
Surface waters may receive considerable additions of dissolved mineral salts from shallow springs which feed the streams.
It contains Chloride, Sulfate, Carbonate, Bicarbonate of Na, P, Ca & Fe.
Not suitable for dyeing & finishing.

3) SUBSOIL WATER:

This type of water is collected from shallow springs & wells which are about 50 ft (15 m) or so deep.
It is usually free from suspended impurities because it has been filtered by its passage through the soil. It'll however contain dissolve organic water.
Subsoil water is often rich in dissolved Carbon di oxide, a gas abundantly present in the skin of the soil.
Subsoil waters are very variable with regard to the impurities which they contain.
Not suitable for dyeing & finishing.

4) DEEP WELL WATER:

This type of water is obtained from 500 m below the surface. It is free from organic matters.
The soluble impurities in water may be composed of a variety of substances. Soluble organic compounds, ammonium salts, Nitrates & Nitrites of animal; or vegetable origin may be found. If they are present in considerable quantities, the sewage contamination is undesirable for many textile purposes.
The presence of salts of Ca or Mg in solution can be most undesirable in many finishing process.

What is Difference between Fashion and Style?

October 14, 2017 3 টি মন্তব্য news

Fashion and Style are two common terms which are now vastly used by the young generation, though they are totally confused about it, cannot differentiate between fashion and style. Just not this young generation, there are so many who still don’t know the difference between fashion and style. “Fashion is about dressing according to what’s fashionable. Style is more about being yourself” said by Oscar de la Renta.

What is Fashion?

Fashion is a very versatile matter and trendy right now, which is being featured in magazines, on TV and on the fashion runways. In another view, Fashion is also the newest creations made by designers, which are brought by only a few numbers of people. Fashion can be anything such like clothes, shoes, make-up and accessories etc which is being made popular by fashion house, models, actors and actresses.

What is Style?

Style is something which is unique to everyone. Style is the persons own choice in clothes, accessories and others. Style is not totally dependent on clothing; it can be related with anything that makes the person looking stylish. In another view, style is the extension of fashion which does not change as fashion.

Objects & Advantages of Garments Washing

October 14, 2017 কোন মন্তব্য নেই washing

Objects of garments washing:

To develop softness in garments: Size materials applied during manufacturing present in the fabric are removed which enhances soft hand feel. Additional softness may be attained by using softener.
To introduce fading effect: Dyes or pigments are present in the fabric, used during coloration, are washed out locally or partially which result fading or worn out effects in the garments.
To create new fashion: Washing Process of garments bring different outlook (faded, color tinted etc) thus creating new fashion for the new generation especially for teenagers.

To satisfy the consumer : As the contraction or extraction (shrinkage) occur due to washing , the wearer can use the garments after purchase satisfactory

Advantages of garments washing:

The following advantages are obtained could be gained from the garments washing—

Removal of starch or size materials makes the fabric soft hand feels.
Softness could be increased by the addition of softener just at the last stage of washing.
Dirt, spots, impurities, gum etc, if purchase.
Faded or worn out effect could introduced to the garments which creates new fashion
Similar outlook can be obtained by different washing techniques.
Comparatively lower capital is required to set up a washing plant.
Accumulated in the garments during manufacturing could be removed.
During washing shrinkage may takes place, therefore after washing there is no possibility to create such problem.
Washed garments could be worn directly after
Lower land space and least manpower cost are required to run a washing plant.

Unavoidable changes / limitations of garments washing :

Like other processes the garments washing is also not without some limitations. They included as below-

Garments size change: Size change takes place due to shrinkage properties of fabric . The amount of shrinkage properties of fabric determines the size change of the garments.
Size material is partly removed: Unfixed dyes may remain on the surface of the garments and it is necessary to remove completely after washing.

Physical properties of textile fibers?

October 14, 2017 টি মন্তব্য fiber

Fiber length

In physical properties the most important is the fiber length on which the quality of yarns depends. For cotton if fiber length increases the quality of yarns will be good, but this is just opposite for wool. In jute the fiber length is too long that sometimes the fibers are cut into small pieces.

If the fiber length is too small it is difficult to produce yarn. Yarn is impossible if the fiber length is less than 0.5 inch. Thin fibers produce thin yarn and coarse yarn is produced from coarse fibers.

There are two types of fiber on the basis of length:

Continuous filament
Staple fiber

Continuous filament

Long and continuous fibers are called filament. Filaments are continuous in length which can be used as such form or cut into shorter staple fiber form. These fibers are collected from both natural and artificial source. Any natural fiber can be made into a filament. When only one filament is used in a yarn then it is called mono filament. When more than one filament are used in yarn then it is called multi filament.

Mono filament → 1.5 holes in spinneret.

Multi filament → 10-100 holes.

Staple fiber

When the length of fiber is short then it is called staple fiber. Stable fibers are manly shorter in length and related to natural fiber. All natural fibers without silk can be collected as staple fiber. Artificial fibers also collected as staple fiber.

Staple fibers are three types on the basis of length:

Short staple: Length is less than 2 inch.

Medium staple: Length is from 2-4 inch.

Long staple: Length is more than 4 inch.

Strength

The capacity of a fiber to support a load is known as fiber strength. The strength is described as tenacity.

Tenacity = Strength/ linear density.

It is expressed as CN/Tex or N/Tex. The tensile strength is commonly described as the force required to reach break the increase in the length before breaking is known as extension.

Elasticity

It is the property to recover from deformation. The fiber may be elastic or plastic which depends upon fiber condition and surrounding environment.

Flexibility

Flexibility is that property to resist repeated bending and folding.

Cohesiveness

It is the ability of the fibers to cling together during spinning depends on crimp and twist. In natural fiber the property comes from nature but in artificial fiber this property is given by crimping.

Fineness

The term fineness describes the quality of a fiber. By this, we know how fine a fiber is. It is expressed by the terms count, tex, denier, tex per unit length etc.

1 Tex = 1 gm/1000m.

1 denier = wt. in gm/900m.

Fineness affects some fiber properties. Such as yarn count, yarn strength, yarn regularity etc.

Cross section

The cross section of a fiber determines the physical properties of fiber. It gives idea about strength, fineness that varies from fiber to fiber. The cross section shape of a fiber is important because it contributes to the surface appearance of the fiber. It helps to give properties of luster, bulk and body of the fibers, yarn and fabrics. It has effect in twisting, bending or shunning.

Crimp

It refers to the waves or bends that take place along the length of a fiber. It increases cohesiveness and resilience, resistance to abortion and gives increased bulk or warmth to fabrics. It also helps fabrics to maintain their softness or thickness, increase absorbency and show contact comforts bid reduces luster. A fiber may have one of the three types of crimp. Namely – Mechanical crimp, natural crimp or Inherent crimp and Chemical crimp.

Resiliency

It is the property of a fiber, which enables it to recover from certain load or stretch over a period of time.

Toughness

The ability of a fiber to endure large permanent deformations without rupture is called toughness.

Work of rupture

The area below the stress –strain curves provides a measure of the work required to break the fiber. It is called work of rupture and it commonly expressed in CN/Tex.

Appearance

It is expressed by length, fineness, cross-section cleanness and luster of a fabric. Generally short fibers are bulky and loss lustrous.

Density

The density indicates the mass per unit volume. The specific gravity of a fiber indicates the density relative to that of water at 4 degree Celsius.

Elongation

It is the ability to be stretched, extended or lengthened. Elongation vary at different temperatures and when wet or dry.

Thermal properties of textile fibers?

October 14, 2017 কোন মন্তব্য নেই fiber

Amorphousness

Amorphousness orientation of polymers within the polymer system of any fiber is called the amorphous region. In other word, if a substance exposed to X-rays and diffuse and broad patterns X-ray diffraction called amorphous substance and the property is called amorphousness. In amorphous regions, the polymers are oriented or aligned at random.

Crystallinity

If a substance is exposed to X-rays, give sharp and well defined X-ray diffraction patterns is called crystalline substance and the property is called Crystallinity. Crystalline orientation of polymers within the polymer system of any fiber is called the crystalline region. In crystalline regions the polymers are oriented or aligned longitudinally into more or less parallel order. It is in the crystalline areas that hydrogen bonding and Vander-Walls forces occur.

Flammability

It is the ability to ignite and burn.

Dye ability

It is the ability of fibers to be dyed.

Mechanical properties of Textile fibers?

October 14, 2017 কোন মন্তব্য নেই fiber

A. Tensile properties

Tensile properties indicate how a material will react to the forces being applied in Tension. Some tensile properties are given below -

Tenacity

Tenacity is the maximum strength to break a fiber.

Breaking extension

It is expressed in percentage. It is the ratio of elongation at break to the initial length and multiple of hundred.

Work of rupture

The total energy needed or work done to break a fiber.

Initial modulus

Initial modulus is the stress needed to double the length of a fiber.

Yield stress

Yield stress is the stress for which the fiber or material starts yielding.

Work factor

It is the ratio of work of rupture to the product of breaking load and breaking extension.

Elastic recovery

The tendency of a fiber to recover its original size and shape. It is the ratio of elastic extension to total extension.

B. Flexural properties

It is the property or behavior shown by the fiber or material when we bend it. The importance of Flexural properties is required when we wear cloth.

C. Torsional properties

It is the property of fiber or material when a Torsional force is applied on it. Here Torsional force is a twisting force that is applied on the two ends of the material in two opposite direction.

D. Frictional properties

Frictional properties are due to the friction between the fibers. These properties are shown during processing. Too high friction and too low friction is not good for yarn. Therefore it is an important property when yarn manufacturing and processing.

What are the objects of blending in spinning?

October 14, 2017 কোন মন্তব্য নেই yarn

(a) Blending influences the reduction of the cost of the final product through blend composition, availability of fibres quality & inherent fibre property variations.

(b) It helps to improve processing performance of the following process–

(i) Carding : Blending influences the processing performance of carding through control of nep level variation, waste level variation, fly, roving twist variation, m/c adjustment, static electricity formation.

(ii) Spgⁿ : Blending influences the processing performance of spgⁿ through control of yarn twist variation, end breakage, m/c adjustment etc.

(iii) Warping & weaving : Blending influences the processing performance of warping & weaving through control of end break m/c adjustment etc.

(iv) Dyeing & finishing : Blending influences the behavior of dyeing & finishing through control of shrinkage variation, dyeing defects etc.

(i) Physical properties : It influences to increases tensile & tear strength, Elasticity, abrasion resistance, stretch etc.

(ii) Aesthetic properties : It influences to increase luster. Appearance, cover, color etc.

(iii) Subjective properties :It increases comfort & the properties like handlings, touch, softness etc.

(d) It helps to meet function & end used requirements.

(e) It helps to achieve effect by carrying color, fibre characteristics & so on.

Chemical properties of textile fibers?

October 14, 2017 কোন মন্তব্য নেই fiber

Acid and Alkali

Acid or alkali is harmful for cellulose and protein fibers. Therefore, the effect of acid and alkali must be known during bleaching, dyeing and finishing. Different fibers react differently with acid and alkali. For example, Cotton and Linen damaged when they are subjected to conc. Hydrochloric, Sulphuric and Nitric acids. Also dilute solution of those acids can make harm to the fibers. On the other hand, conc. alkaline solution is not harmful to Cotton and Linen. Wool is not affected by dilute solution of acid. But conc. acid and alkali damage wool easily. So acid or alkali must be chosen properly to use in different purpose and processing.

Water

Water is very important to determine the properties of fibers. According to the behaviors of fibers with water, fibers are classified into two groups – hydrophobic and hydrophilic. Water is used in process like scouring, dyeing etc.

Moisture Regain

Moisture regain is expressed as percentage. It is the ratio of oven dry weight of a material to the weight of water in this material and multiple of hundred.

Moisture Content

Moisture content is also expressed as percentage. It the ratio of oven dry weight of a material to the total weight (oven dry weight + weight of water in this material) of the material.

Absorbency

Normally, textile fibers absorb moisture. The ability of fiber to take up the moisture is known as absorbency. The absorbency is expressed in the terms of moisture regain. Among the all fibers cotton absorbs easily. For the property cotton requires more time to dry. Moisture regain of wool is 16%. It is 10% for silk. But it seems like dry after regain for silk. The cloths we wear are more comfortable which ability is higher to absorb.

Heat

Effect of heat si a vital point during dyeing, ironing, steaming and some other operations. Different fibers behave differently under heat. Some fibers burn where some scorch when heat is applied. Some fibers are not combustible e.g. mineral fiber, glass fiber etc. Cotton is easily flammable, wool is hardly flammable fiber.

Sunlight

When we wear cloth or fabric it comes into the touch of sunlight. It is very familiar to us. Effect of sunlight should be kept in mind for general people. Sunlight reduces the strength of cotton and it becomes yellow. Linen is better than cotton in sunlight. But cotton is better than silk.

Biological agent

If the fibers are attacked by bacteria’s, black spots are seen on the fibers as a result of which the strength of fiber is reduced. Its importance whether fibers attached by micro-organisms or not upon which strength of products depends. Cotton, Linen and rayon attacked by fungus. Silk, wool, acetate, tri-acetate and spandex have better resistance to mildew and other insects.

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