Properties Of Reactive Softener || Advantages And Disadvantages Of Reactive Softener

Reactive softener is not so used softener as cationic and nonionic softener. It is applicable to all fibers and it gives permanent finish to the textile materials.

Properties of Reactive Softener: The properties of reactive softener are given below.

• Reactive softener can be applying on all types of fibers.


• Reactive softener reacts with –OH group of cellulose and form covalent bond and gives permanent finish.


• Its washing fastness is good.


• It is soluble in water.


• After application, it needs to cure.

Methods of application: Pad – dry- calender method is used to apply the reactive softener. This could be done as the follow. It is a sample application parameter.

Reactive softener        : 25 – 30 g/l

Temperature              : 90⁰C

Curing                       : 140⁰ – 150⁰ C

Time                         : 4 – 5 minutes

Advantages and Disadvantages of Reactive Softener: Advantages and disadvantages of reactive softener are given below.

Advantages of Reactive Softener:

1. The softening effect of reactive softener is durable.


2. It does not cause yellowing problem.


3. In case of resin finished fabrics, it minimizes the loss in tensile strength, tear strength and abrasion resistance.


4. Application is easy.

Disadvantages of Reactive Softener:

• The reactive softener is comparatively costly than other softener.

So, from the above, we see that, reactive softener is reliable to apply to all kinds of fibers but it is more costly than other softening agents.

Properties Of Amphoteric Softener | Properties Of Silicon Softener

Amphoteric softener and silicon softener are not widely used. Silicon softener is the latest types of softener.

Properties of Amphoteric Softener: These molecules consist of one or longer alkyl chains attached to polar molecules which contains both anionic and cationic groups. Their nature depends on P^H.

Neutral P^H: No ionic

Lower P^H: Cationic

Higher P^H: Anionic

Properties of Silicon Softener: The uses of silicon softener are given below.

• Silicon softener is a latest softener and it is used for bulky effect in high quality cotton towel.


• Silicon softener is expensive.


• It is very durable in laundering.


• Silicon softener improves tear strength, wrinkle recovery.

Although this two softener is not popular to all but day by day the application of silicon softener is increasing rapidly.

Properties Of Nonionic Softener || Advantages And Disadvantages Of Nonionic Softener

Nonionic softener is widely used on synthetic fibers and their blends. It is compatible to use for synthetic fibers.

Properties of Nonionic Softener: The Properties of nonionic softener are given below.

• Nonionic softener is applied to synthetic fibers and their blends.


• It is fairly soluble in water.


• Its color is like creamy paste.


• Hot water should not used during the application of nonionic softener.


• Acetic acid is added to cold water before adding the softener.


• Nonionic softener is chemically fatty acid, ethylene oxide condensates etc.

Methods of Application: Nonionic softener is used on fiber by the following way.

1. Pad – dry – calender method


2. Exhaust Method

Advantages and Disadvantages of Nonionic Softener: The advantages and disadvantages of nonionic softener are given below.

Advantages of Nonionic Softener:

1. Nonionic softener is compatible with cationic, anionic agents, starch and resin.


2. It does not create yellowish problems.


3. It is applicable for all types of fibers.


4. Nonionic softener can be applied in both exhaust and padding processes.


5. It is compatible with silicon and cationic products used in finishing formulation.


6. It does not influence on dyeing fastness.


7. When treated fibers are heated it does not become yellow.


8. Nonionic softener does not influence dye fastness.


9. It does not irritate human skin.


10. It is suitable for cheese dyeing process.


11. It provides bulky and heavy feel.


12. It keeps fabric low yellowing.

Disadvantages of Nonionic Softener:

1. Nonionic softener gives temporary soft feel.


2. It is comparatively costly then other softener.


3. Not easily soluble in water.

So, when you will choose the softener, you have to consider the effect of that’s softener to the textile materials.

Properties Of Anionic Softener || Advantages And Disadvantages Of Anionic Softener

Anionic softener is not so used as cationic softener. Anionic softener is applied on cellulosic and its blend textile materials.

Properties of Anionic Softener: Properties of anionic softener are given below.

• Anionic softener is applied on cellulose and its blend.


• Anionic softener is not permanent and not fast to repeated washing.


• It is not stable in hard water.


• It has not enough affinity to cellulose.


• Examples of anionic softener is oil, fat, wax, soap, sulphated and sulphonated oils and sulphated fatty alcohol.

Methods of Application: Anionic softener is applied on the fabric by the following way.

1. Fad – dry – calender


2. Exhaust Method (Jigger / Winch)

Advantages And Disadvantages Of Anionic Softener: The advantages and disadvantages of anionic softener are given below.

Advantages Of Anionic Softener:

• Anionic softener is compatible with direct dyes, optical brightener, starch, resigns etc.

Disadvantages Of Anionic Softener:

1. Anionic softener gives temporary finish on the textile materials.


2. It gives poor softness.


3. Because of less substantively, wastages become high.

Uses of Anionic Softener: Anionic softener is used in the following cases.

• Anionic softener is used to modify the softness of resin treated fabrics.


• Anionic softener is used as the lubricant for fiber during carding and drawing in spinning.

Anionic softener has lots of limitation for this reason its application area is smaller than cationic softener or nonionic softener.

Properties Of Cationic Softener || Advantages And Disadvantages Of Cationic Softener

Cationic softeners are one of the important softening agents used for finishing process. It is widely used for softening the cellulosic materials.

Properties of Cationic Softener: The properties of cationic softeners are given below. They are-

1. Cationic softeners are widely used on cellulose materials.


2. It has enough affinity and substantively towards cellulosic fibers.


3. Its P^H is lies between 5 – 6.


4. Cationic agents become unstable to alkaline media.


5. It is soluble in water.


6. Cationic salts present in hard water react with softener forming precipitation.


7. Chemically cationic softener is sap amines, amido amines, imidazoline and quaternary ammonium compounds.

Preparation of Softener Solution: Softener solution is made by following way.

1. At first, take required softener.


2. Then, take required amount of water at 70⁰C.


3. After that, softener and water is mixed by stirring.


4. Finally, acetic acid is added in the solution.

Methods of Application: Softener is applied on fabric by the following two ways.

1. Pad-dry-calender: In this method, 20 -25 g/l softener are taken where P^H level is 4 – 5. Then, fabric is impregnate in to water and the pickup % is 70 – 80. Then fabric is dried at 120⁰ - 140⁰C for 2 – 3 minutes.


2. Exhaust Methods (Jigger or winch): In this method, following parameters are maintained. It is a sample recipe.

      Americos AC 1000 : 1 - 2% (owf)

Material: Liquo : 1: 10

           Temperature : 45⁰ – 50⁰ C

                P^H : 4 – 5

                            Time : 20 – 30 minutes

Advantages and Disadvantages of Cationic Softener: Advantages and disadvantages of cationic softener are given below.

Advantages of Cationic Softener:

• Cationic softener increases lubricity of yarn.


• It minimizes the loss in physical property on resin finished goods.


• Permanent finish is done by cationic softener.


• It can be used as antistatic agent for loose fiber.

Disadvantages of Cationic Softener:

• Cationic softener gets precipitated when with anionic compounds.


• It is not compatible with other additives.

So, when you will choose cationic softener, you should remind the properties of cationic softener as well as the advantages and disadvantages of cationic softener.

Softening Agents || Requirements Of Softening Agents || Types Of Softening Agents

Softening agents are one of the finishing agents which give softness, better handle, drape, cutting and sewing qualities to fabric. Softening agents are applying on fiber, yarn, woven or knitted fabrics during dyeing process. Softening agents are applying on the materials at the last stage of dyeing process. Most of the time softening agents applies on fabric by softener machine. Various techniques are applied for softening agent application.

Requirements of Softening Agents: Following requirements should be fulfilled by a softening agent. They are-

• Physical properties of the fabric should not be affected by softening agent.


• Softening agents should be compatible with other finishing chemicals.


• It should not affect the fastness properties of dyed and printed materials.


• It should not create any yellowish problem to the fabric.


• Softening agent should not affect the depth and tone of dyed or printed fabrics.


• Softening agent should not give irritation to human skin.


• Softening agent should have strong properties on own.

Types of Softening Agents: Softening agents are classified according to their chemical properties. Softening agents are classified as the following way.

1. Cationic Softener


2. Anionic Softener


3. Nonionic Softener


4. Reactive Softener


5. Amphoteric Softener


6. Silicon Softener

Above softening agents are used for softening of the fabrics. The application of the softening agents depends on the types of textile materials. All of the softening agents are not suitable for all types of textile materials. Faulty selection of softener agents could be harmful for the dyed or printed fabrics.

So, we should have deep knowledge about the various types of softening agents.

Direct Dyes || Properties Of Direct Dyes

Direct dyes are sodium salt of sulphonic acid and most of them contain an azo group as the main chromophore. Direct dye dyeing is carried out in alkaline condition. This dyeing process is done comparatively in low temperature. After absorbing dyes it tends to bleeding of dyes which produce unevenness of shade, to resist these different types of after treatment is done.

Direct dyes are anionic dyes substantive to cellulosic fibers when applied from an aqueous bath containing electrolyte. Many of them also dye protein fibers. Direct dyes are very easy to apply and available in the market.

Properties of direct dyes: Direct dyes have some characteristics. Followings are the main properties of direct dyes.

• Direct dyes are water soluble dyes.


• It is anionic in nature.


• It needs electrolyte for exhaustion.


• Dyeing process is carried out in alkaline condition.


• Generally applied for cellulosic as well as protein fibers.


• Fastness properties are average specially wet fastness.


• Fastness properties are improved by after treatment.


• It is not widely used as compared with reactive dyes.


• Comparatively cheap in price.


• Direct dyes are used for cheap goods for local market.

It is not suitable to dye cellulosic fiber with direct dyes for this reason most of the cases reactive dyes, basic dyes and azoic color is used. The use of direct dyes is very limited.

So, choose your direct dyes according to your requirements.

What Is Vat Dyes || Properties Of Vat Dyes

Vat dyes are different from reactive dyes, disperse dyes, basic dyes, acid dyes or azoic color but its application process is near similar as sulphur dyes. Vat dyes are used for coloring cellulosic fiber specially cotton fiber. It is widely used for run the dyeing process of cotton yarns which is used for producing jeans or denim product.

The word vat is come from vessel; vat dyes can be applied in a vat for coloration textile products. Vat dyes are natural coloring materials which are solubilized in a vat by the fermentation process called vatting.

Vat dyes are insoluble in water but it becomes in soluble form by vatting process. The process of converting insoluble vat dyes into soluble form is known as vatting.

Properties of vat dyes: Vat dyes have lots of properties which are required to remember before and during dyeing process. Followings are the main properties of vat dyes.

• Vat dyes are natural coloring dyes.


• Vat dyes are insoluble in water.


• Vatting process is needed for making the insoluble vat dyes into soluble form.


• Final color is developed by the oxidation process.


• Vatting is done in alkaline condition.


• Fastness properties of the dyes are excellent but its rubbing properties are not so good.


• Sometimes, it causes different types of skin disease.


• Vat dyes are mainly used for coloring cellulosic fibers.


• Stability of the color in the fiber is excellent.


• Wide range of color can be achieved by these dyes.


• Application of vat dyes is limited in practical life.


• Vat dyes are expensive in price.

So, it’s very interesting that most of the denim product is colored by vat dyes.

What Is Basic Dyes || Properties Of Basic Dyes

Basic dyes and its application in dyeing and printing process are interesting. Jute fiber and its generated products are treated with basic dyes. I have written about the jute fabric printing with basic dyes in one of my blog post. I think that’s will help you to know about the printing process of basic dyes.

Basic dyes are called cationic dyes because when salts of organic bases are ionize into anionic and cationic part that’s time cation is the responsible for color production. On the otherhand basic dyes are basically hydro-chloride or salts of organic bases. Generally they are in-soluble in water but it becomes in soluble form when treated with alcohol or methylated spirit. Basic dyes dyeing are carried out in acidic form. Dyeing process for different fibers are varies.

Properties of basic dyes: Like other dyes; basic dyes have some own characteristics. Followings are the main characteristics of basic dyes:

• Basic dye is a synthetic class dye.


• Cationic part of the salt is responsible for color production.


• Basic dyes are water insoluble but soluble in alcohol and methylated spirit.


• Basic dyes are hydro-chlorides or salts of organic salts.


• Basic dyes are applied in acidic condition.


• Very brilliant shade can be produced by basic dyes.


• Fastness properties of these dyes are average to good.


• Mainly basic dyes are suitable for jute dyeing and jute printing but wool, acrylic fibers also can be dyed by basic dyes.


• Leveling properties of these dyes are very poor.


• Cotton has no affinity for basic dyes but dyeing of cotton could be carried out by mordanting, fixing and dyeing operation.


• Basic dyes are comparatively cheap in price.

We know that reactive dyes, azoic color, sulphur dyes are used for dyeing cellulosic fiber but basic dyes also can be apply for this.

So, do your job and dye and print your product with basic dyes.

Sulphur Dyes || Properties Of Sulphur Dyes

Sulphur dyes are one of the most used dyes for producing bright black and brown shade on cellulosic fiber products. The chemistry of sulphur dyes dyeing is near similar to vat dyes dyeing. In both case final color is developed by the oxidation process. Although, reactive dyes, azoic color is available but sulphur dyes is preferable for black shade production.

Sulphur dyes are so called because sulphur dyes contain di-sulphide (S-S) linkage in their chemical structure. Sulphur dyes dyeing process is carried out in alkaline condition. Sulphur dyes are used for both dyeing and printing.

Properties of sulphur dyes:

• Sulphur dye is water insoluble dye.


• It needs solubilization for application (with reducing agent).


• Oxidation is needed for final color development.


• Sulphur dye is applied in alkaline condition.


• Electrolyte can be added in the dye to enhance exhaustion of dyes.


• Fastness properties are average.


• Best suitable for producing black and brown shade on the textile materials.


• It is mainly applied on cotton, viscose and staple fiber.


• Its exhaustion properties are good.


• Most of the times dyeing is carried out in 80-95 degree Celsius.


• Sulphur dye is comparatively cheap in price.

Although sulphur dyes have a lots of advantage but it has some disadvantage like-

• Bronziness of shade: For this defect some white spot can be appear in the fabric.


• Sulphur black tendency: This have sulphur black tendency.

So, when you will choose your dyes; check out the properties which should have dyes.

What Is Azoic Color | Properties of Azoic Color

Azoic Color is produced by the combination of Naphtha or coupling component and Diazo component. Production procedure of Azoic Color is different from other dyes production process. Azoic color is different from other dye and its application process is also different.

Azoic Color is called Ice Color or magic color because it needs low temperature and after coupling color is produced within few seconds. Color fastness properties are good to excellent.

Properties of Azoic Color: Properties of Azoic Color is given below:

• Azoic Color is a water insoluble dye.


• Azoic Color is composed of two components; such as

1. Azoic coupling component


2. Azoic Diazo component

• For color production, coupling is necessary.


• Coupling is done in alkaline condition.


• Applicable mainly for cellulosic fibers.


• The time of application is lengthy.


• Very bright shade can be produced by Azoic Color.


• A fastness property of the textile material which is dyed by Azoic Color is good to excellent.


• Azoic Color is comparatively cheap in price.


• Dyeing process is run by three processes - Naphtholation, Diazotization and Coupling.


• Final color is produced within few seconds after immersing the textile materials in the dye solution.

Azoic Color is used for coloring small amount of textile materials dyeing. It is suitable for small scale industry. Azoic color dyeing process is not popular as reactive dye or disperses dye dyeing.

So, select your dyes as you need.

Disperse Dyes | Properties Of Disperse Dye

Disperse dyes are synthetic dyes. Disperse dye is one kind of organic substances which is free of ionizing group. Disperse dyes are less soluble in water and used for dyeing synthetic textile materials. Disperse dyes is mainly used for dyeing polyester yarn of fabric. in the other hand, Reactive dyes are used for coloring cotton or cellulosic fiber.



A question could be appear in your mind that why this dye is called disperse dyes? It has a simple answer. Disperse dye is so called because it is non soluble and molecularly dispersed therefore dispersing agent is necessary for coloration with disperse dyes.

Properties of Disperse Dyes:

• Disperse dye is one kind of organic substances which is free of ionizing group.


• Disperse dye is non-soluble in nature.


• Disperse dye is insoluble in water.


• Dispersing agent is needed for dyeing with disperse dyes.


• Fastness properties specially wet and light fastness is good to excellent.


• Disperse dyes are applied in acidic condition.


• Disperse dyes are widely used for dyeing synthetic fibers. Polyester fiber is dyed by disperse dyes but nylon, acrylic also can be dyed with this.


• Disperse dyes dyeing is carried out in high temperature.


• In some case carrier method is applied for dyeing of polyester with disperse dyes


• Disperse dyes are economical.


• Molecular size of disperse dyes are smaller than other dyes.


• Disperse dyes are derivatives of azo, anthroquinone, nitro and quinine groups.

Disperse dyes dyeing is carried out in high temperature for this reason dyeing machine should have the capability of serving this process.

Different dyes manufacturing companies manufacture disperse dyes. Choose your color brand on which you can trust for better dyeing.

Functions Of Chemical Auxiliaries Used In Wet Processing | List Of Chemical Auxiliaries

We know that dyes and chemicals are the main factor for producing color in yarn of fabric. Different types of chemicals are used during dyeing. In different stages of dyeing processing, various chemicals are used. Every chemical have their own characteristics and they are used in different stages of wet processing.



List of Chemical auxiliaries used in wet processing unit and their function is given bellow:

1. Acid: Acid is used to control P^H. Acid decrease the pH of the solution. If P^H 1-7 then it is called Acidic solution.


2. Basic: Basic is used for increase the P^H of the solution. P^H range of basic is 7-14. This also used as scouring agent.


3. Peroxide Killer: This chemical is used to kill per oxide which is remaining in the material. Peroxide is harmful for the material. A test is carried out to measure the amount of peroxide present in the solution.


4. Bleaching Agent: Bleaching is carried out before dyeing or printing operation. Better absorption of dyes depends on better bleaching. Absorbency test is carried out to test the bleaching performance. Absorbency time should lie under 5 second. It is used for removing natural color from the grey yarn or fabric.


5. Salt/Electrolyte: Salt is used as electrolyte. Salt increase the exhaustion rate of the dyeing process. Different types of salt are used for different shade. The amount of salt used depends on the shade % of the material.


6. Scouring Agent: Scouring agent is used to remove fat, waxes, fragments of cotton etc.


7. Antifoaming Agent: Foam is formed during bleaching and dyeing process. Anti foaming agent is used to resist foam formation. If foam formed it reduces the dyeing uptake %.


8. Sequestering Agent: This agent is used to remove hardness of water.


9. Dispersing Agent: This agent is used for disperse dyes. We know, disperse dye is insoluble in water and dye present in disperse form. By applying this agent dye molecule breaks and become soluble in the solution.


10. Neutralization Agent: This agent is used to neutral the P^H of the solution.


11. Wash/Soaping Agent: Soaping agent is used for washing. It needs to wash dyed material to remove unfix dye from the material. Dark material needs double wash. But light shade materials needs single wash, sometimes no wash is carried out for light shade. It also increases the reflecting properties.


12. Softening Agent: This agent is used to increase softness of the material. This agent used as finishing material.


13. Fixing Agent: This agent is used for fixing of dyestuff and also remove the unfix dye.


14. Brightening Agent: This agent is used to increase the brightness of the material. This agent increases the reflecting property of the material. Standard reflecting value is 85%. But sometimes it is possible to increase it up to 95%. But it is risk because it needs high kier boiler temperature, which reduces the strength of material.

So, we should use the chemical auxiliaries according to their scope of use.

List Of Basic Chemicals Used for Knit Dyeing | Chemicals And Auxiliaries

Chemicals are second important materials for dyeing knit fabrics. Chemicals are different in their properties. Chemicals are mixed in dyeing machine with the dyes. All chemicals are not suitable for all types of dyeing. Specific dyes need specific chemicals. Use of chemicals depends on the dyes type. Some chemicals are strong alkaline some are weak and some are moderate in nature.



I have given some chemicals name list which is widely used for getting better dyeing performance. They are as follow:

Basic Chemicals

1. Acetic Acid


2. Oxalic Acid


3. Soda Ash


4. Sodium Hypo chloride


5. Sulphuric Acid

Bleaching Agent   

1. Hydrogen peroxide 50%

Salt or Electrolytes

1. Glubar salt


2. Common Salt


3. Refined Salt


4. Caustic Soda


5. Caustic Soda Pear

Detergent & Scouring Agent

1. Invadine DA


2. Invatex CS


3. Cibafluid C

Anti foaming/Penetrating Agent

1. Cibaflow Winch


2. Cibaflow C


3. Antifoam TC


4. Primasol NF

Anti creasing Agent

1. Ciba fluid P


2. Ciba fluid C


3. Primasol Winch

Peroxide Stabilizer

1. Lavatex


2. Prestozen PL


3. Stabilol P


4. Tinoclarito G-100

Sequestering Agent

1. Ladiqueast 1097


2. Dekol SM


3. Sirrix AKLiq

Peroxide Killer

1. Invatex PC


2. Lorinol PK


3. Basopal PK

Reactive Fixing Agent

1. Cibafix Eco


2. Tinofix FRD


3. Cycianon E

Mercerizing Wetting Agent

1. Mercerol QWLF


2. Leophen MC

After Soaping Agent

1. Cibapor R Liq


2. Sandopour RSK


3. Geiclean AW

Enzyme Finishing Agent

1. Bio polish AL

Optical Brightener for Cotton

1. Uvitex BBT


2. Uvitex CIDN


3. Uvitex BHV

Optical Brightener for Polyester

1. Ultraphore BN Liq


2. Uvitex BHT


3. Ultraphore SFG Liq


4. Ultraphore SFR

Leveling Agent for polyester

1. Baso Winch PEL


2. Osimol ROL


3. Uniperol EL


4. Prote-Gal DP505

Decolourant For Effluent Treatment

1. Colfloc RD

Above chemicals are manufactured by different chemicals manufacturer. Before buying the chemicals ones should be confirm about the properties of chemicals. Chemicals properties should be checked in lab for ensure about the quality because qualified chemicals can give qualified output.

So, apply your favorite one in knit dyeing process.

 

What is Pigments || Comparison between Dyes and Pigments

Pigments are the special type of dyeing or printing materials for wet processing technology. It is not so easy task to print or dye a material by pigments, because pigment is 100% water insoluble. So it needs to take special technique for pigment dyeing or printing. Generally pigment is use for printing.



Pigments can be define as a water insoluble coloring material mostly mineral origin have been used for coloration of metal, wood, stone and textile materials. Pigments have different types of chemical characteristics. Some examples of pigments are given bellow:

1. Dioxazine


2. Fluorubine


3. Isoindoline


4. Perylene perinone


5. Pyrocoline


6. Quinacridone


7. ETC

Dyes and pigments are the main coloring materials. So we have to know about the comparison between dyes and pigments, which will give us a clear idea about this two.

Dyes	Pigments
Generally organic materials are dyed or print	Organic and inorganic both types are dyed or print
It is water soluble	It is completely water insoluble
It contains auxo chrome in their chemical structure	No auxo chrome contains in pigments
Color fastness generally average to excellent	Color factness is average to good
Its application method is very easy	Need binder for application
It is generally used for dyeing	Generally used for printing
Dyes are expensive than pigments	Pigments are generally inexpensive than dyes
Dyes have attraction for fibers	They have no attraction for fibers
It applies selectively on textile materials	All fibers can be color

In modern times pigment use to dyeing cotton fabric besides printing. Different types of pigment are supplied by different well known dye and pigment manufacturing companies.

Reactive Dyes | Definition-Classification-Properties and Influencing Factors

Dyeing operation is performed by the reaction between fiber and dyes. Some dyes are water soluble and some are water insoluble. Some fiber has affinity to dye; some have no affinity to dyes. So dyeing depends on both fiber and dyes chemical properties. Before dyeing we have to consider this factor.



Reactive dyes are the most common and huge uses dyes all over the world. Most of the dyeing operation of natural fiber is done by reactive dyes. Reactive dyes have a worldwide acceptance to the dyeing technologist for dyeing cotton. This article is about reactive dyes.

Reactive dye is only class of dyes which makes co-valent bond with the fiber and becomes a part of it. This can be described as:

Reactive dyes + Fiber = Reactive dye-Fiber (Co-valent bonding)

If the general structure of a reactive dye is “R-B-X” then,

R-B-X + Fiber = R-B-X-Fiber (Dyed fiber)

Here,

R = Chromophore Group (Azo, Anthaquinone, Phthalocyanine, Metal complex group)

B = Bridging Group ( Imino, Ethyl & Methyl, Oxide, Sulphide group)

X = Reactive Group (-Cl, -Br, -SH, -OCH, etc)

Examples of reactive dyes:



Classification of Reactive Dyes:

• By depending on chemical constitution reactive dyes can be classified as:

1. Chlorotriazine Dyes (MCT)


2. Vinyl Sulphone Dyes (VS)


3. Heterocyclic Helogen Containing Dyes (HHC)


4. Mixed Dyes (MCT-VS)

• By depending on application methods of temperature, reactive dyes can be classified as:

I.Cold brand reactive dyes: This type of reactive dyes is applied in very low temperature. Temperature lies between 25 -50 degree Celsius. They are highly reactive with fiber on this temperature.

II.Medium brand reactive dyes: This type of dyes is applied in a medium temperature range is 40 – 60 degree Celsius. Their reactivity is medium with fiber.

III.Low brand reactive dyes: This type of dyes has very low reactivity properties with fiber with comparison with medium and high brand reactive dyes. Dyeing is carried out on 60 -90 degree Celsius.

Properties of reactive dyes:

1. Reactive dye is anionic in nature.


2. Reactive dye is a water soluble dye.


3. They have better wash and light fastness properties.


4. They have better substantivity.


5. They form strong co-valent bond with the cellulosic fiber.


6. Alkaline condition is must required for dyeing.


7. Electrolyte is must for exhaustion of dyes in the fiber.


8. A certain amount of dyes are hydrolyzed during application.


9. Wide range of color can be produced with reactive dyes.


10. Comparatively cheap in price.

Influencing factors: Dyeing of cellulosic fiber with reactive dyes is influenced by some factor. Following factors should consider during dyeing operation.

1. pH: Reactive dyeing is done in an alkaline conditon for this reason pH of the dyeing bath should control. pH should be between 11.5 -11.


2. Temperature: Temperature should fix depending on the brand of reactive dyes.


3. Concentration of electrolyte: Concentration of electrolyte depends on the type of shade.


4. Time: Dyeing time should be between 60 – 90 minutes.


5. Liquor ratio: Huge amount of water is use during dyeing operation. Higher the liquor ratio betters the efficiency of dyeing.

Reactive dyes have some advantage and disadvantage to use. Different famous dyes manufacturing companies produce reactive dyes with different characteristics. So, select your ones depending on your demand.

 

Dyes | Classification Of Dyes

Dyeing and dyes; this two word is related with one another. Without dyes it’s not possible to dye materials. So dye is the main thinking of dyeing. But most of time we do something wrong for what we face a lots of problem during dyeing. For this reason we should know about dyes, which we use in our dyeing process.



 

Dyes are coloring materials used in dyeing textiles. Other hand it can be defined as a substance which may be natural or synthetic use to change or add color to the textile materials. Applying of dyes on materials depends on the type of materials. Different materials have different chemical structure and different dyes had different chemical structure, so we have to know which dye is suitable for which materials.

Depending on dyes chemical structures, it is classified as bellow:

• Readymade dyes

1. Water soluble dyes:
   
   
   
   1. Direct dyes
   
   
   2. Acid dyes
   
   
   3. Basic dyes
   
   
   4. Reactive dyes
   
   
   5. Optical whiteners
   
   
   
   


2. Water insoluble dyes:
   
   
   
   1. Vat dyes
   
   
   2. Sulphur dyes
   
   
   3. Disperse dyes
   
   
   
   

• Ingrain dyes

1. Azoic colors


2. Oxidation colors


3. Mineral colors

Natural dyes are the dyes which are produced naturally from different plant source like roots, leaves, bark, berries and fungi, wood, lichens etc. Very beginning of the dyeing history man started dyeing their materials by natural dyes. Indigo, woad, saffron and madder are the plant based dyes which is much popular in Asia.

Synthetic dyes occupied the marked of dyes. Now a day most of the dyeing operation is done by synthetic dyes. Different factor is responsible for it. Synthetic dye is made from the reaction of two or more chemicals.

Another dye is food dye, which is not as an industrial dye. A higher standard is maintained during processing. It generally used as a food additives. Generally direct dyes, vat dyes and mordant dyes are used. Food dyes standard also controlled hardly by legislature.

Dyes can be water soluble or water insoluble. Some dyes are anionic, some are cationic or some has both anionic and cationic properties. Some dyes need low temperature and pressure for make a solution, some needs high temperature and pressure for make a solution. All of the properties of dyes depend on the molecular structure of dyes.

Now, dye molecule bears some group which is responsible for producing a color. Chromophore group is responsible for color production. The color bearing unsaturated group of a dye molecule is called Chromophore group. Some chromophore groups name is given bellow:

1. Ethylenic


2. Nitro


3. Azo


4. Keto


5. Nitroso


6. Thioketo


7. Quinonoid


8. Acridine

We know about Chromogen. The compounds containing a chromophore are called Chromogen. We know that the leaves of plant are green because it contains chromogen. Also Auxochrome is color helping group, it does not produce color itself but depends on the color of chromogen. Auxochrome may be acidic either basic like OH or NH_2, COOH, NR₂ etc.

Dyes are very sensitive to atmospheric condition. So it needs to keep in a standard atmospheric condition. Different world famous companies are trying to improve the properties of dyes. So by the research we can get more efficient dyes for the next day.