Natural Dyes | Classification of Natural Dyes | Plant Dyes | Plant Dye | Natural Plant Dyes | Insect Dyes | Insect Dye | Animal Dyes | Animal Dye

Dyes : Substances that add color to textiles. They are incorporated into the fiber by chemical reaction, absorption, or dispersion. Dyes differ in their resistance to sunlight, perspiration, washing, gas, alkalies, and other agents; their affinity for different fibers; their reaction to cleaning agents and methods; and their solubility and method of application. Various classes and types are listed below.

Natural Dyes

Natural dyes are dyes or colorants derived from plants, invertebrates,a or minerals. The majority of natural dyes are vegetable dyes from plant sources from roots, berries, bark, leaves, and wood and other organic sources such as fungi and lichens.

Plant Dyes | Plant Dye

There is a whole variety of plants which can be used to make plant dyes. Different parts of plants are used to make dyes – for example, the leaves, the skins of fruit, the bark, roots or wood. Lichens are very small plants which grow on rocks. There are many colours of lichens and they are very good for making dyes.

Natural Plant Dyes

• Alkanna tinctoria
• Indigofera suffruticosa
• Anthemis tinctoria
• Bixa orellana
• Caesalpinia echinata
• Catechu
• Common Tormentil
• Cordeauxia edulis
• Cryptocarya alba
• Dyewoods
• Eucalyptus fibrosa
• Eurasian smoketree
• Gardenia jasminoides
• Genista tinctoria
• Haematoxylum campechianum
• Haemodorum coccineum
• HennaIndigo dye
• Indigofera
• Indigofera tinctoria
• Isatis tinctoria
• Juglans regia
• Lithospermum caroliniense
• Lomatia hirsuta
• Maclura tinctoria
• Mallotus discolor
• Mallotus philippensis
• Morinda citrifolia
• Morinda tinctoria
• Oldenlandia umbellata
• Pentaglottis sempervirens
• Pokeweed
• Pomegranate
• Psorothamnus emoryi
• Quercus velutina
• Reseda (plant)
• Reseda luteola
• Rubia
• Rubia cordifolia
• Safflower
• Saw-wort
• Tansy
• Trihydroxyanthraquinone
• Turmeric
• Wild Angelica
• Wrightia tinctoria

Insect Dyes | Insect Dye

Example of an insect Dye is the Kermes dye obtained from the dried bodies of the female insects ( Kermes vermilio Planchon and Kermes ilicis ) which were found in southern Europe on the small evergreen kermes oak ( Quercus coccifera )The history of the Kermes dye dates back to the ancient Egyptians and Romans. Kermes dye was produced by a process of drying the bodies of the insects and then fermentation.

• Cochineal

Animal Dyes | Animal Dye

Animal-based dyes could be created from shellfish.

Carmine

Cochineal

Hexaplex trunculus

Polish cochineal

Tekhelet

Tyrian purple

Washing Fastness Test | Wash Fastness | Description of Washing Fastness | Types of Washing Fastness

Color Fastness:

Color fastness is the ability of fabrics to retain the dyes used to color them. Some fabrics hold dye within their fibers extremely well - like denim - while others do not (mostly synthetic or artificial non-natural fabrics) and tend to “bleed” when they are washed. The denim would therefore be more “color fast” than the other fabric.

The resistance of a material to change in any of its color characteristics, when subjected to washing is called color fasntess to washing.

General Principle:
A specimen of the textile to be tested, with the adjacent fabric attached is subjected to washing under specifiend conditions. Te extent of any change in color and that of the staining of the adjacent fabric are assessed and the rating is expressed in fastness numbers.

There are two types of adjacent fabrics; (1) single fibre fabric and multiple fibre fabric. In the case of multifiber fabric only one specimen is required and in the of single fiber fabric two adjacent faabric are required.

There are various colorfastness tests. Details of washing fastness tests are given below.

Fastness to Washing:
In the test, change in color of the textile and also staining of color on the adjacent fabric are assessed. A 10 x 4 cm swatch of the coloured fabric is taken and is sandwitched between two adjacent fabric and stitched, The sample and the adjacent fabric are washed together. FIve different types of washing are specified as different washing mthods.

Fastness to Wash
Sr.No	Method	Washing severity	Soap+Soda in grams/liter	Time in minutes	Temperature	Steel balls
1	IS:687:79	Very mild like hand wash	5	30	40+/- 2	Nil
2	IS:3361:79	5 times severe than method 1	5	45	50+/- 2	Nil
3	IS:764:79	Mild washing	5 + 2	30	60+/-2	Nil
4	IS:765:79	Severe washing	5 + 2	30	95+/-2	10
5	IS:3417:79	Severe washing	5 + 2	4 hrs	95+/-2	10

 

The solution for washing should be prepared to the required temperature of washing. The liquor material ratio is 50:1 . After soaping treatment, remove the speciment, rinse twice in cold water and then in running cold water under a tap. Squeeze it and air dry at a temperture not exceeding 60°C. The change in color and staining is evaluated with the help of grey scales.

Quality Control | Apparel Quality Management | Apparel Quality Management for Apparel Exporters | Garment Quality Control | Garment Quality Index | Apparel Quality Control | Textile Quality Control

Quality Control:

Quality control is a process by which entities review the quality of all factors involved in production. This approach places an emphasis on three aspects. Quality control emphasizes testing of products to uncover defects, and reporting to management who make the decision to allow or deny the release, whereas quality assurance attempts to improve and stabilize production, and associated processes, to avoid, or at least minimize, issues that led to the defects in the first place.

1. Elements such as controls, job management, defined and well managed processes, performance and integrity criteria, and identification of records
2. Competence, such as knowledge, skills, experience, and qualifications
3. Soft elements, such as personnel integrity, confidence, organizational culture, motivation, team spirit, and quality relationships.

   

   Quality Check

The quality of the outputs is at risk if any of these three aspects is deficient in any way.

Apparel Quality Management:
There are a number of factors on which quality fitness of Apparel industry is based such as - performance, reliability, durability, visual and perceived quality of the garment. Quality needs to be defined in terms of a particular frame¬work of cost. The national regulatory quality certification and international quality programmes like ISO 9000 series lay down the broad quality parameters based on which companies maintain the export quality in the garment and apparel industry. Here some of main fabric properties that are taken into consideration for garment manufacturing for export basis:

• Overall look of the garment.
• Right formation of the garment.
• Feel and fall of the garment.
• Physical properties.
• Colour fastness of the garment.
• Finishing properties of apparels
• Presentation of the final produced garment.

Apparel Quality Management for Apparel Exporters:
For a garment exporter or apparel exporter there are many strategies and rules that are required to be followed to achieve good business. The fabric quality, product quality, delivery, price, packaging and presentation are some of the many aspects that need to be taken care of in garment export business. Some rules that are advisable for garment exporters are listed below:

1. Quality has to be taken care by the exporter, excuses are not entertained in international market for negligence for low quality garments, new or existing exporters for both it is mandatory to use design, technology and quality as major upgradation tools.
2. Apart from superior quality of the garment, its pricing, packaging, delivery, etc has to be also taken care of.
3. The garment shown in the catalogue should match with the final garment delivered.
4. It is important to perform according to the promises given to the buyer, or else it creates very bad impression and results in loss of business and reputation.
5. In international market, quality reassurance is required at every point.
6. Proper documentation and high standard labels on the garment are also important aspects as these things also create good impression.
7. Timely delivery of garments is as important as its quality.
8. If your competitor has the better quality of garment in same pricing, it is better to also enhance your garment quality.
9. Before entering into international market, garment exporters have to carefully frame out the quality standards, or else if anything goes wrong it could harm the organization. And after that strictly follow it.
10. The garment quality should match the samples shown during taking the orders.
11. The garment exporters should know to negotiate a premium price after quality assurance is done.
12. Quality is a multi-dimensional aspect. There are many aspects of quality based on which the garment exporters are supposed to work.
13. Quality of the production.
14. Quality of the design of the garment.
15. Purchasing functions’ quality should also be maintained.
16. Quality of final inspection should be superior.
17. Quality of the sales has to be also maintained.
18. Quality of marketing of the final product is also important as the quality of the garment itself.

 

Termal Properties of Textile Fibers

The property which is shown by a textile fiber when it is subjected to heating is called thermal property. Thermal properties are including:

1. Thermal conductivity

2. Heat of wetting or heat of absorption

3. Glass transition temperature

4. Melting temperature

5. Heat setting

6. Thermal expansion

 

Thermal conductivity: 

Thermal conductivity is the rate of heat transfer in degree along the body of a textile fiber by conduction. Higher the thermal conductivity indicates the fiber more conductive. Thermal conductivity is measure by co-efficient of thermal conductivity.

 

Heat of wetting: 

When a textile fiber absorb moisture or water it gives of some amount of heat which is called heat of wetting or heat of absorption. Heat of absorption resulting from changes in moisture regain rather than the thermal conductivity. If 1gm of dried textile fiber is completely wetted then heat in calory/gm is involved which is known as heat of wetting for that fiber.

Glass transition temperature(Tg): 

The temperature up to which a fiber behaves hard as like glass and after which it behaves soft as like rubber is called Glass transition temperature and it is denoted by Tg. The range of Tg is lies between -100˚C to 300˚C

 

Melting temperature: 

A temperature at which fiber melt completely is called melting temperature. At melting temperature fiber losse its identity and convert it into a viscous liquid. At melting temperature fiber also losse its strength and some molecular weight.

 

Thermal expansion: 

Thermal expansion can be measured by co-efficient of thermal expansion and which is defined as the fractional increase in length of a specimen to rise in temperature by 1˚C. Co-efficient of thermal expansion ═ Length increased / initial length of specimen ═ ∆L / L ═ L2-L1 / L1

 

Heat setting: 

Heat setting is the process of stabilizing the form of fibers, yarns, fabric or garment by means of successive heating or cooling in dry and wet condition.

Static Electricity

 

If two surfaces come in close contact with each other, then charge is created due to friction between them. The produced charge remains enclosed and static in those surfaced. They can not move from one place to another place. Here only charges are exchanged between two surfaces. This type of electricity is called static electricity.

Problem caused by static electricity in textile:

 

1. Similar charge repel each other:

a) The filament in a charged warp will blow out away from one another.

b) This causes difficulties in handling materials.

c) There will be ballooning of a bundle of sliver.

d) Cloth will not fold down neatly upon itself when it comes off a finishing machine.

 

2. Different charge attracts each other:

a) Difficulties in the opening of the parachute.

b) Different parts of garments may be stick together.

3. Attraction between charged particles & charged textile materials:

a) Roller lapping may occur.

b) Dust, Dirt’s etc may be attracted by the textile material as a result materials become dirt.

c) Soiling of cloth may occur.

d) Fibers may stick to the earthed parts of the machine.

Methods of minimizing static electricity: 

1. By using conducting liquids like emulsion, oil, friction between the materials ca be reduced as a result, static electricity will be minimize. 
2. By increasing relative humidity of the atmosphere, static electricity can be minimized.
3. By using anti-static agent on the materials static problem may reduce.
4. By ear thing the metallic part of the machinery static electricity can be minimized. By blending conductive materials with non conductive materials, static electricity can be minimized.

Fiber migration:

Migration occurs during spinning both in staple and filament yarns. The effect of migration is more pronounced in staple yarn than in filament yarn. The migration of fiber affect on many properties of fiber as like elongation and strength. According to the textile institute “The change in the distance of a fiber or filament form the axis of a yarn during production is called fiber migration.

Structure of Textile Fiber | Physical Structure of Textile Fiber | Molecular Structure of Textile Fiber

Requirement of fiber formation or fiber forming polymer:

1) Polymer should have long & linear chain molecules.

2) They must be chemically resistance.

3) Molecular chain must be parallel to each other.

4) They should have attractions.

5) Some measures of freedoms of molecules movement due to give required extensibility.

6) Lateral forces to hold the molecules together and gives cohesion the structure.

Methods of fiber structure investigation:

1) X-ray diffraction method

2) Infra-red radiation method

3) Electron microscopic method

4) Optical microscopic method

5) Thermal analysis

6) Nuclear magnetic resonance methods

7) Density

8) General physical properties

9) The chemistry of fiber material

Properties of x-ray diffraction method:

1) Determination of chemical groups

2) Determination of molecular spacing

3) Determination of chemical bonding

4) Determination of degree of crystallinity & orientation

5) Determination of water absorption

Properties of Infra- red radiation absorption method:

1) Determination of spiral turns or convolution of cotton fiber

2) Determination of molecular spacing

3) Determination of chemical bonding

4) Determination of degree of crystallinity & orientation

5) Determination of molecular packing

6) Determination of cross-sectional shape of fiber

7) Identifications of fiber

Crystallinity:

Crystallinity is the arrangement of fiber molecules in the molecular chain.
Properties of crystallinity:

1) More dense 

2) More stiff

3) More strength

4) More rigid

5) Less water absorbent

Measurement of crystallinity:

1) X-ray diffraction method

2) Infra-red radiation absorption method

3) Density measurement methods

Orientation: Orientation is the arrangement of molecular chain of fiber.
Properties of Orientation:

1) More dense 

2) More stiff

3) More strength

4) More rigid

5) More water absorbent

6) More lustrous

7) Less elastic as less extension

Measurement of Orientation:

1) X-ray diffraction method

2) Infra-red radiation absorption method

3) Density measurement methods

Effects of structural factors on fiber properties:
1) Chemical bonding:

a) Single bond-More strength, less flexibility 

b) Double bond - Less strength, more flexibility

2) Character of polymer chin: 

a) Long chain, such as [-CH2-CH2-CH2-CH2-CH2-CH2-]n-More strength, less flexibility
b) Sort chain, such as [-CH2-CH2-]n-Les strength, more flexibility 

c) Long side chain-More strength, less flexibility
d) Sort side chain-Less strength, more flexibility 

 

3) Molecular packing: 

a) Regular packing: More strength, less flexibility
b) Irregular packing: Less strength, more flexibility 

 

4) Crystallinity: High crystallinity, higher strength and less flexibility 

 

5) Orientation: High Orientation, higher strength and less flexibility

6) Nature of monomer:

a) Same monomer (Homopolymer) -More strength, less flexibility
b) Same monomer (Co-polymer) -Less strength, more flexibility

7) Internal structure of fiber polymer: 

a) For ring structure -More strength, less flexibility 

b) For normal structure -Less strength, more flexibility

Torsional Properties of Fiber | Torsional Properties of Textile Materials

It is the property of fibre 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. The behaviors which are shown by a textile material when it is subjected to a torsional force is called torsional property.

1. Torsional rigidity

2. Breaking twist 

3. Shear modulus

1. Torsional rigidity:  

Torsional rigidity can be defined as the torque required against twisting is done for which torque is termed as torsional rigidity.Mathematically, torsional rigidity = ηET2/ρ

Where, 

η = shape factor, 

E = specific shear modulus (N/tex)

Specific torsional rigidity: Specific torsional rigidity can be defined as the torsional rigidity of a fiber of unit linear density.Mathematically, specific torsional rigidity = ηE/ρ

Unit: N-m2 /Tex

2. Breaking twist:  

The twist for breaking of a yarn is called breaking twist. It also can be defined as the number of twists required to break a yarn. Breaking twist depends on the diameter of fiber and it is inversely proportional to its diameter.That is, Tb ∞ 1/d

Where, 

Tb = Breaking twist, 

d = diameter of fiber

Breaking twist angle: This is the angle through which outer layer of fiber are sheared at breaking. Mathematically, α = tan-1(πdTb)

Where, 

α = breaking twist angle, 

d = diameter of fiber, 

Tb = breaking twist per unit length 

Frictional Property of Textile Fiber

When the textile materials are processed, then friction is developed between the fibers. The properties which are shown by a textile material during friction is known as frictional property. This 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.

Frictional properties depend on-

1. Composition of the material

2. State of the surface of the material

3. Pressure between the surfaces

4. Temperature

5. Relative humidity %

Co-efficient of friction:  

Frictional force is proportional to the normal or perpendicular of a material due to its own weight.That is, F ∞ N Or, F = μ N Or, μ = F/NWhere, F = Frictional force, N = Normal / perpendicular forceHere, μ is the proportional constant known as “co-efficient of friction”.So, co-efficient of friction can be defined as the ratio of frictional force and perpendicular force.

Methods of measuring co-efficient of friction:  

Capstan method is most commonly used to measure co-efficient of fraction. Capstan method can be classified into two classes-

1. Static capstan method

2. Dynamic capstan method

Other methods- 

1. Buckle & Pollitt’s method

2. Abboh & Grasberg method

3. Gutheric & Olivers method

Influences of friction on textile material:

Friction holds the fibers in a sliver and hence the sliver does not break due to its’ own weight. Friction helps in drafting and drawing.· Uniform tension can be maintained during winding & warping because of friction.· Friction helps to make yarn by twisting during spinning.· Friction increases lusture and smoothness of the yarn and the fabric.· Friction makes more clean material. 

Demerits of friction on textile material:· 

Friction causes nap formation.· High static friction causes high breakage of yarn during weaving.· If the frictional force is high, the handle properties of fabric will be low.· Friction generates temperature and therefore static electricity is developed which attracts dust, dirt etc. and the materials become dirty.· Sometimes due to over friction materials may be elongated.· Friction increases yarn hairiness.· Friction worn out parts of machine.

Minimization of friction intensity:  

1. Sizing is done in warp yarn before weaving to reduce frictional intensity. As a result, yarn damage will be reduced.

2. Emulsion, oil, lubricants etc. are specially applied on jute fiber to reduce friction.

3. Chemical treatment is done on wool fiber to reduce scale sharpness and thus reduce friction during processing.

4. By calendaring frictional intensity of cloth is reduced.

5. Sometimes resin finish is applied on fabric to reduce friction.