PRINTING OF TEXTILES · 2018-04-10 · During the paste preparation all other chemicals, dyes, thickening paste are mixed together. But dissolved soda ash, which is for the fixation

Basic Principles of

PRINTING OF TEXTILES

( VOLUME- II )

Mandeep Nagpal

B.Tech (Tectile Chemistry), PGDMM, PGDCA

Lecturer, Textile Processing, Govt. Polytechnic Hisar

DEPARTMENT OF TECHNICAL EDUCATION , HARYANA

PANCHKULA

Dedicated to my bereaved loving parents who taught me

the value of hard work and my teachers who opened the

gates of knowledge for me to share it with others.

TABLE OF CONTENTS

Sr. No Pg.No.

Preface

Acknowledgement

About the author

SECTION – A

( Printing of cotton fabrics by Direct style of printing )

1 Unit – 1 General

Terminology of printing of textile in general , general paste recipe , methods

and styles etc.

2 Unit – 2 Printing of cotton fabrics with water soluble dyes

2.1 Printing with Direct dyes

2.2 Printing with Reactive dyes

2.3 Printing with Solublised Vat dyes

2.4 Printing with Rapidozen and Rapidfast colour salts and concept of

illuminating colors.

3 Unit – 3 Printing of cotton fabrics with water insoluble dyes

3.1 Printing with Vat dyes

3.2 Printing with Azoic colors

3.3 Printing with Sulphar dyes ,

3.4 Printing with Aniline Black colors etc.

4 Unit – Printing of cotton fabrics with Pigment Colours

4.1 Printing with Pigment Colors

4.11 General about pigments

4.12 Ingredients of pigment printing paste and their purpose

4.13 Mechanism of pigment printing

4.14 Advantages and disadvantages of pigment printing

4.2 Printing with Phthalocyanine pigments .

Multiple choice questions based on above topics.

SECTION – B

( Printing of cotton fabrics by Discharge style of printing )

5 Unit – 5 General principles about discharge and resist styles of

printing and selection of discharging and resisting chemicals.

6 Unit – 6 Discharge style printing on

6.1 Cotton fabrics Dyed with Direct dyes

6.2 Cotton fabrics Dyed with Reactive dyes

6.3 Cotton fabrics Dyed with Vat dyes

6.4 Cotton fabrics Dyed with Solublised vat dyes

6.5 Cotton fabrics Dyed with Azoic colors

6.6 Cotton fabrics Dyed with Aniline Black

6.7 Cotton fabrics Dyed with Rapidozen and Rapid fast colors

salts. Concept of illuminating colours

7 Unit – 7 Resist styles printing on

7.1 Cotton fabrics to be dyed with Reactive dyes as ground

colours.

7.2 Cotton fabrics to be dyed with Solublized vat dyes as ground

colours.

7.3 Cotton fabrics to be dyed with Aniline black colours as

ground colours.

8 Unit – 8 Concept of Khadi Printing, White and Coloured Khadi

prints.

Multiple choice questions based on above topics

SECTION – C

9 Unit – 9 Printing of cotton fabrics with special styles of

printing

9.1 Tie and Dye printing

9.2 Crimp Style of printing,

9.3 Burn out style of printing,

9.4 Polychromatic style of printing-

9.4.1 Dye weave technique

9.4.2 Flow form technique

10 Unit – 10 Transfer printing, its principle, machines used and

their working, advantages and limitations.

Multiple choice questions based on above topics

PREFACE

Textiles like any other product, since its use by the man for wearing and for

other purposes, is in continuous innovation as far as its manufacturing

principles or technology is concerned. Decoration of textiles is an essential

feature of the textile making. It is the area which plays a key role in

enhancing the quality, appearance, aesthetic properties and in turn market

value of the textile produced. This has been dealt mainly by two ways.

Firstly it is done by crafting the design either inside the weave/knit or on the

surface by embroidery and producing various kinds of ornamentations

leading to many novel varieties of fabrics. Secondly it is done through novel

application of colors on textiles by dyeing and printing of textiles. It is

somewhat cheaper than producing the woven designed fabrics. Latest

technological developments in process and machinery has helped a lot in this

regard However both the ways of decorating the fabrics are essential to

meet the demand of the market.

This book titled “ Basic Principles of Printing of Textiles – Vol. II ’’

is basically written as a text book for the diploma holders in the fields of

Textiles and other allied fields like Fashion Design/Technology. It deals

with the specific methods of printing of cotton fabrics with different classes

of dyes, and the technical details involved in it. It has been specifically

designed as per the latest examination pattern of State Boards of Technical

Education Haryana as well as Punjab and is divided into three sections.

Section - A deals with the printing of cellulossic ( specially cotton ) fabrics

with different classes of dyes by Direct Style of printing. Section -A has

been further subdivided into different units dealing separately with water

soluble dyes, water insoluble dyes and printing with pigment class of

colorants. Section – B deals with the printing of cotton fabrics with various

suitable classes of dyes by Discharge Style and Resist Style of printing.

Section – C basically deals with Transfer Printing and some special styles

of printing . Multiple choice questions have been given at the end of all these

sections to facilitate the students for preparing for the exams. This is a first

little endeavor from me in this field and is merely an introductory work.

Hope this will be liked by the students and and the staff in general. This

might have lots of errors, so suggestions for its improvement and betterment

are always most welcome.

Mandeep Nagpal

ACKNOWLEDGEMENT

Before going further I would like to pay my due regards to all

those responsible for, that this little effort of mine could take shape. Very

firstly I would thank the Almighty without which nothing can happen in this

world. Thereafter I would like to thank our worthy Director General

Technical Education, Haryana who improvised and encouraged to take up

this kind of work of preparing cheap and simple study material for the

students of Diploma streams. I am certainly thankful to my wife Ritu who

played a key role to accomplish this work.

Unit-1 General Introduction

Before we move further let us get ourselves with some general terminology

printing or dyeing of textiles:

Dye – Dye may be defined as the most basic coloring component without

which no coloration of fabrics can be imagined. It can be water soluble or

water-insoluble. In case of printing of textile materials with dyes ‘steaming’

is essential process.

Pigment – Pigments are neither water soluble nor can be made water-

soluble.

General recipe for making printing paste.

1) Thickner :- Thickners are found in powder form. Different thickners

are used with different types of dyes.

Ex :- In case of direct dye, starch Gum Tragacanth is used. Qty of

thickners 50% or more 600-700 gram thickner is used in one k.g.

paste.

2) Dye :- X% depending upon shade % age.

3) Hygroscopic agent :- 5-15% age.

Hygroscopic agent absorb the moisture from steam. It can be urea,

glycerine or any product of glycerine.

4) Chemicals :- Alkaline Medium

e.g. Weak –Alkali – T.S.P [Tri-Sodium Phosphate. This is mostly uses

in direct dye.

Quantity – 0.5%

Alkaline medium is used to increase the solubility of dye. There will

be according to the class of dye.

5) Water :- To adjust the viscosity and to dissolve the dyes and

chemicals. Qty will be as per the viscosity required.

Unit – 2 Printing of cotton fabrics with water soluble

dyes

2.1 PRINTING OF COTTON FABRIC WITH DIRECT DYES

Direct dyes are water soluble dyes and can be applied to cotton fabrics

directly. These dyes have good affinity for cellulosic fibres like cotton,

viscose etc. The most suitable thickener for printing of these dyes is the

mixture of Starch Thickener and Tragacanth Gum thicknener. Mixture

thickener can be prepared by mixing thickening pastes of these two

thickeners in the ratio of 40:60.

PRINTING PASTE RECIPE :

Direct Dye – X gm (depending

upon % shade of print)

T.R.O. _ 5-10 %

T.S.P. (Tri Sodium Phosphate) _ .01- .05 %

Starch Tragacanth Thickening : _ 50% or more

Glycerine : _ 5-10%

Water/thickening paste: _ To adjust the viscosity

------------------------------------

Make the paste = 1 Kg

-----------------------------------.

PROCEDURE :

Print the cotton fabric by above paste. Dry the fabric partially and

then steam at 100°-105°C for 5-15 minutes. During which the dye present in

the printing paste absorbs the moisture present in the steam with the help of

the hygroscopic agent added in the printing paste (Glycerine for direct dye)

and gets dissolved. Now it is automatically taken up by the cotton fabric.

After the steaming process material is washed to remove the extra thickener

and chemicals present in the the fabric. After this the material is dried.

Aftertreatment

Finally we can treat the printed fabric with cationic dye fixing agent ( 5

gms/litre) at a temp. of 70-80oC for 15-20 min.to improve the washing

fastness.

Process Sequence

Print → dry → steam

FUNCTION OF DIFFERENT INGREDIENTS :

TRO : is used as wetting agent for the dye

TSP : This is a mild alkali and it increases the solubility of the dye

Glycerine : It acts as a hygroscopic agent to absorb moisture during

steaming.

2.2 PRINTING OF COTTON FABRIC WITH REACTIVE DYES

BY DIRECT STYLE :

GENERAL : Reactive dyes are the major class of dyes which are used

on cotton fabrics for dyeing and printing. This is because of their eco-

friendliness, low cost and satisfactory fastness properties. Following are the

important types of reactive dyes which are in use in industry on large scale

* MCT ( mono-chloro triazinyle) dyes - For example Procion-M dyes

* DCT (di-chloro triazinyle) dyes. - For example Procion - H dyes

* VINYLE SULPHONE dyes - For example Ramazol dyes

* Tetrachloro pyrimidine dyes - For example Reactone dyes

* Special reactive dyes for printing - For example Procion Supra

and Cibacrone Pront dyes.

METHODS OF PRINTING REACTIVE DYES BY DIRECT STYLE ;

There are four methods of printing of cotton with reactive dyes

( procion class ) :

1. Steaming method

2. Dry heat process

3. Alkali pad process

4. Air development process

1. STEAMING METHOD : This is the most versatile method of

printing used for all the types of Reactive dyes


Reactive dye - X gm.( depending upon %

Shade)

Sodium Alginate thickening - 50 % or more

Urea - 5-15 %

Soda ash(Sodium carbonate) - 1-1.5 %

Resist Salt - .01 %

Water/thickening paste - To adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------.

PROCEDURE :. During the paste preparation all other chemicals,

dyes, thickening paste are mixed together. But dissolved soda ash, which is

for the fixation of the reactive dye, is added just before printing. Because if

we will add soda ash along with other ingredients in the start it can lead to

hydrolysis of the dye and lighter print will be obtained. Mix all the above

mentioned chemical and make a smooth paste. Print the cotton fabric

followed by drying and steaming at 100-105°C for 5-15 min. After this

material is washed and dried:

Process Sequence :-

Print with alkali Dry Steam Wash off Dry

FUNCTION OF DIFFERENT INGREDIENTS

Sodium alginate - acts as thickener

Sodium carbonate - acts as fixing agent

Urea - acts as hygroscopic agent(moisture absorbing

agent)

Resist Salt - It is a mild oxidizing agent to prevent the reduction

of the dye due to the presence of any reducing

fumes.

2. DRY HEAT PROCESS :

Principle : This is based on the principle that when the prints are not to be

steamed or if provision of steaming is not there, then hot brand reactive dyes

can be printed by dry heat process. Shades similar to or brighter than those

produced by steaming process can be obtained in the dry heat process. In

this method cotton fabrics after printing are fixed by curing ( subjecting the

printed fabric to dry heat ) in a curing chamber instead of steaming.

However the quantity of the hygroscopic agent is double of that used in

the steaming method.

PRINTING PASTE RECIPE

Procion Dye - X gm. .( depending upon %

Shade)

Urea - 5 to 20 %

Sodium Alginate - 50 % or more

Resist Salt - 1.0 %

Sodium bicarbonate - 1.0 to 1.5 %

Water/thickening paste - To adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------.

Procedure; Mix all the above ingredients using a mechanical stirrer and

make a smooth paste. Now print the cotton fabric with this paste followed by

drying and curing . Resist salt (10g/kg) is also necessary. Cold brands may

be fixed by heating at 100°C for 3 min. while hot brand need a curing temp.

of 140°C (and 150°C for viscose) and a curing time of about 5 minutes. Cold

brand reactive dyes may be fixed by taking 15 g/kg sodium bicarbonate and

hot brands require 15g/kg sodium carbonate.

Process sequence :-

Print with alkali Dry Cure Wash off Dry

3. ALKALI PAD-PROCESS :-

PRINCIPLE : This method is based on the high reactivity of the cold

brand reactive dyes which get fixed very rapidly on cellulosic materials. The

rapid reaction of cold brand reactive dyes and cellulose under the influence

of heat and moisture has been used to fix the prints. It is done by passing the

cloth in a cylinder drying range. This method is mostly applicable for cold

brand dyes.


In this case print paste recipe is same as that of the steaming method

however, alkali ( sodium carbonate) may or may not be added to the printing

paste. If the alkali is incorporated, the printed cloth has lower storage

stability.

PROCEDURE :

Cloth is printed with the paste and then it is nip-padded or cover printed.

with 20 g/lt. sodium bicarbonate in the presence of sodium alginate.Sodium

hydroxide, if used, may lead to bleeding n the padding trough. The cloth is

immediately dried on steam heated cylinders. When the fixation takes place

and bleeding in the pad liquor or onto the print is negligible. Finally the

cloth is rinsed, soaped at the boil, washed and dried.

Process sequence;

Print with or without alkali –Dry--- Pad with alkali --- dry--- wash---Dry

4. AIR DEVELOPMENT PROCESS :-

This is another method of printing of cold brand reactive dyes.Reasonably

good degree of fixation can be achieved for cold brand reactive dyes by this

process. Hot brands are unsuitable. Good yields can be obtained on

mercerized cotton and viscose rayon. But the yields on un-mercerised cotton

are poor when fixed by this process.

Procedure : 1. The cloth is first padded with 2% sodium-carbonate solution

2. Drying preferably on a cylinder dryer.

3.It is then printed with a paste prepared according to the steaming recipe

but in the absence of sodium-bicarbonate.

4. The cloth is then allowed to dry by hanging in the air for several hours.

5. It is then rinsed, soaped at the boil, washed and dried

Process Sequence:

Print without alkali on alkali padded cotton cloth hang in air wash

dry

2.3 PRINTING WITH SOLUBILISED VAT DYES

Introduction:-

Solublised vat dyes, as the name suggests, are the soluble form of the

vat dyes ( otherwise water insoluble ) and are available in powder form.

These are generally of light colour such as cream or light-brown. These

dyes have the following properties

• These are easily water soluble thereby paste formation of these

dyes is very easy.

• Have good affinity to textile fibres.

• These dyes are sensitive to light.

• Ease of development. When a solution containing H2SO4 ( acid )

and NaNO3 ( oxidizing agent ) or Potassium dichromate is added

to an aqueous solution of solublised vat dyes at 50°C-70°C temp.

This leads to regeneration of the original vat dyes. The reaction

take place in an acidic medium and oxidizing medium and is called

“Development”. .

METHODS OF PRINTING SOLUBLISED VAT DYES

Following are the methods of printing solublised vat dyes by direct style

of printing:

1. STEAMING METHOD OR CHLORATE METHOD:

Principle

When a paste containing solublised vat dye, an oxidizing agent, a catalyst

and an acid librating agent ( generally ammonium salts of mineral acids like

sulphates, chlorides, nitrate, sulphocyanide etc. ) is printed on a well

prepared cotton fabric followed by steaming. It leads to the following

reaction

NH4X NH3 + HX

Under these conditions (boiling), ammonia (NH3) is given up leaving

the acid in the solution. Thus the acidity of the solution increases. This

generates the proper development conditions automatically on the prited

fabric and the colour of the dye appears thereby making the print.

Printing Paste Recipe :-

Solubilised vat dye - X gram depend on shades %

Starch Tragacanth - 50% or more

Glycerine - 5-15%

Ammonia sulphocyanide - Equal to amount of or dye or

sulphate of dye

Sodium Chlorate - 0.5-1%

Ammonia Hydroxide - .01 %

Ammonium Vanadate - .01 %

Water/Reduction thickening - To adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------

Procedure :-

1) First the fabric is printed with above paste.

2) Fabric is then dried out and steamed for 5-15 min. in a rapid ager at

100°C to 102°C.

3) After steaming the cloth is rinsed, soaped at boil, washed and dried.

Purpose of chemicals :-

1) Ammonium sulphocyanide :- Acts as an acid librating agent and

librates acid during steaming as explained in the principle..

2) Sodium Chlorate :- Acts as an oxidizing agent required essentially in

the step of development..

3) Ammonium hydroxide :- It is an alkali and prevents the premature

development of the solublised vat dye in the paste during printing.

4) Glycerine :- Acts as a hygroscopic agent to increase the solubility of

the dye.

5) Ammonium Vanadate :- It acts as a catalyst and it accelerates the

development of the dye during steaming.

NITRITE METHOD :-

This is somewhat improved method of printing for sensitive colours in

solublised vat dyes.This is a wet development method. The ptg. paste

contains the sulublised vat dye and sod. Nitrite in addition to Hygroscopic

agent, solvent and an alkali.

Neither the acid not the acid liberating agent is present in the ptg.

paste the print solubility is very good. The development of dye is carried out

by a short passage through a soln of H2SO4.

The acid and sod. nitrite to produce the oxidizing agent (Nitrous acid)

which along with the acid converts the solubilised vat dye into the vat dye.

In a modification of the nitrate sod. nitrite is not added to the ptg.

paste. The subsequent development being carried out in a bath containing

sulphuric acid H2SO4 and sod. nitrite.

This method is suitable for those dyes which can be developed at or

below 30°C temp in a bath containing sod. nitrite and H2SO4 acid.

Paste Recipe :

Solubilised vat dyes X gm depending on shade %

Starch Tragacanth 50% or more

Urea 5-15%

Sodium Nitrite Equal to amt of dye

Sodium Carbonate 2-3 gm

H2SO4 0.2%

Glabauber salt 0.2%

Water to adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------

Purpose of ingredients :-

1) Sodium nitrite :- To produce the oxidizing agent which alongwith acid

converts the solublised to vat dye into the vat dye.

2) Sodium carbonate : To increase the ptg. paste stability.

3) Urea :- As a hygroscopic agent to minimize evolution of a unpleasant

nitrogen dioxide fumes.

4) Glauber salt :- To minimize the stripping of the solubilised.

Process:-

1) The cloth is printed with above purpose.

2) Then it is passed through with open width of for through a bath

containing.

3) Sulphuric Acid 20 ml/lt

4) Glauber’s salt 20 gm/lg

4) Chromate-Method :- When soluble chromates are actified,

dichromates are treated with an alkali, chromates are formed of these

two, only the dichromates is the oxidizing agent and chromate has no

oxidizing power.

Ptg.- Paste Recipe :

Solubilised vat dye - X gm%

Starch tracaganth paste - 50% or more

Ammonium-Hydroxide - 20 gm/25% of dye

Sod. Chromate - equal to amount of dye

Ammonium chloride - 3-5 gm

Water - To adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------

Purpose of chemicals :-

1) Ammonium chloride and sod. chromate:- Ammonium chloride is

first neutralized and chromate is converted into dichromate there by

erating an acidic oxidizing conds. which are needed for the

development of the solublised vat dye.

2) Ammonium hydroxide :- To be made distinelity alkali.

Procedure :-

1) The cloth is tofd. by above paste recipe.

2) Then cloth is dried.

3) After this cloth may be treated with an acid bath at 50°C for 20-

30 seconds.

4) Steamed the cloth for 5 mtr. in a rapid-ager.

5) Finally, the cloth is rinsed, soaped of the boil, washed and

dried.

4) Aluminium chlorate method :- This method is characterized by the

fact that if does not require steaming for development since

aluminium chlorate is powerful oxidizing agent. Care should be taken

to see that the cloth is not oxidized (damaged).

Ptg. Paste Recipe :-

Solubilised vat dye :- X% depend upon

Starch Tragacanth :- 50% or more

Glycerine :- 5 to 15%

Aluminium chlorate :- 30 gm

Water :- To adjust the viscosity

------------------------------------

Make the paste 1 Kg

-----------------------------------

Procedure :-

1) First the fabric is print with above paste.

2) Then it is dried.

3) After this it is allowed to lie for 2 hrs. for R. temp.

4) Then it is rinsed, soaped and then lwashed and dried.

5. Ferric Chloride Method :- The cloth is printed with a paste confg.

The solublised dye, a solvent, (Glycerine) and a thickner (starch-

tracoganth) in the absence of any oxidizing agent. The development is

then carried out in a bath containing

Ferrid chloride - 30 gm

Sulphuric acid - 20 gm

Glauber salt - 30 gm

At 40°C for 10-30 seconds. Then it is rinsed soaped and then washed

and dried. A short stmg. may be carried out.

6. Copper sulphate method :- There is a danger of degradation of the

cloth taking place in this method.

The cloth is first ptd. with a paste contg. The solublised vat dye

solvent and the thickening agent in the absence of any oxidizing agent. It is

then padded with a solution contng. “Copper sulphate” and lactic acid and

immediately dried on a cylinder dryer.

During drying, acidic oxidizing conds. are created and the solublised vat

dyes is converted into the vat-dye.

7. Chlorite method :- This method is based on the fact that when cotton

cloth is printed with a suitable thickeners of solubilised vat dye in the

presence of sod. chlorite and the ammonium salt and then subjected to the

action of saturated steam, the acidic oxidizing lands created on lead to the

dept. of the solublised vat dye.

2.3 PRINTING WITH RAPDOZEN AND RAPID FAST COLOURS

(SOLUBILIZED AZOIC)

Rapidozen colour salt :-

Formation of Rapidozen colour salt :-

Diazotised base + Amino compound –

Stablised diazotized base + Naphthol (Soluble) + NaOH

Rapidozen :-

Rapidozen colour salt are prepared by diazotion of the base followed

by reaction of the Diazonium salt with a suitable amino compound (-NH2)

(Stablised form) to give a diazoamino compound. This is mixed with the

required napthol. The diazo amino compound dose not have coupling power

with each other under neutral and alkaline conditions.

This mixture dissolve in aqueous solution of an alkali which is needed

to dissolve the naphthol. The mixture give as the rapidozen colour salt.

Rapidozen colour are also called diazomino compound.

Printing paste recipe :

Rapidozen - X gm.

Starch tragacanth - 50% or more

T.R.O. - 20-30 gm

NaOH - 30 gm


After drying the printed cloth with the above recipe. It may be

developed by any of the followed method.

Advantage :-

1) No extra check alkali.

2) Extra temp. is not required.

3) Steaming is not required.

4) Easily soluble

5) Full range of colour.

Rapid Fast colour :-

Rapid fast colour are mixture of antidiazotate and naphthol anti form

of the Diazotate dose not cople with a sodium naphthol. When this mixture

is brought in a acidic conditions.

The principle of stabilization is used in making rapid fast colours. It is

stable in alkaline conditions. Rapid fast ‘H-Brand’ is more stable the other

brand.

Diazotised Base + NaOH = Anti Diazotatett soluble sodium

Printing Paste Recipe :

Rapid fast colour - 50 gm

Starch thagacanth - 50% on more

NaOH - 20-50 gm

T.R.O. - 20-30 gm


After printing and during development process take place.

Process :- Print Dry Steaming After treatment Development

Procedure :-

Print the cotton fabric with this paste and dry it. After this material is

development by any one method.

Airing for 12 hours in a moist room or by a passage through a solution

containing –

Acidic acid – 30 ml/lit

Genuben salt – 50 gm.

Then cloth is rinsed a soaped at the boil washed and dried.

2. To printed cloth may be dried and steaming for 3 min. in a rapid ager

at 102-105°C and then treated with a solution containing :- Acidic

acid 30 g pl, Gluben salt – 50 gm. Rapid fast colour is also called

Antidiazotate colour.

Illuminating colour:

Aniline black repidozen colour, rapid fast colour and solubilized vat

dye have one think is common regarding printing of these colour by direct

style. The development of these colours is done under acidic and oxidizing

condition. After development all these colours show a special effect is called

illuminating effect. Repidozen, rapid fast and aniline black colour provides

very bright colour in red, orange, yellow, magenta, blue and black. Where as

solubilise vat dye gives as very-2 light shades. So in contrast with these light

colour rapidozen, rapid fast and aniline black act as illuminating colour.

Unit – 3 Printing of cotton fabrics with water insoluble

dyes

3.1 Printing with Aniline black by direct style :-

This is an oxidation colour which is used to print or dye black colour

on cotton material.

Principle of aniline black colours :-

This colour is made by oxidation of aniline oil and aniline salt which

gets converted to different stage of colour eg. Dark green to dark brown to

greenable black to fully jet black. This oxidation are takes place into present

of acid lebrating agent and oxidizing agent (like solublised vat dyes).

Different stages

Aniline salt + Aniline oil

Acidic oxidation – Light green shade – dark green – dark brown –

greenable black – Jet black

Printing paste with aniline black :-

Aniline Salt - 10%

Aniline oil - 5%

Starch tragacanth - 500 gm. or more

Sodium clorate (O.A.) - 25 gm

Pottasium Ferrosinite of Ferrocynide - 5%


Process :-

1. Cotton material is printed with above recipe.

2. Drying

3. After this method is hunged in a room where development of the color

take place in about 15-18 hours. The temp. is room temp (35-40°C)

Or

Material may be steamed after drying in a rapid ager for 2-3 minutes.

4. Finally material is chromed. It is solution of potassium dichromate

under acidic condition. After this we get a black print on the fabric.

3.2 PRINTING WITH VAT DYE ON COTTON BY DIRECT

STYLE

Introduction

Vat dyes are water insoluble dye. Generally vat dyes produced prints

of excellent all round fastness properties.

These are can be made water soluble with the help of an alkali like

potassium hydroxide. Sod. Carbonate and a reducing agent like rangolite-C

or sod. Hydrosulphide.

The paste brands of vat dyes are specially developed for use in

printing.

Based on the dyg. principle of vat dyes. There are two methods of

print vat dyes by direct style.

1. Potash-Rongalite Method

2. Potash-Caustic Method

1) Potash-Rongalite Method

This is widely used method of because of its simplicity and reliability

of results. Vat dyes may be used with or without reduction. In the case of

pre-reduction method either or powder brand may be used while in without

pre-reduction paste brands are preferred.

A) With pre-reduction :- In this case first vat dye is converted into its

form by the addition of caustic soda and sodium hydrosulphide in a

separate container.

Separately thickener paste is prepared. Thickener use in this case is

(glycerine) Starch – Tragacanth. A hygroscopic agent is also added

with the thickening paste and the whole mixture is stirred giving a

final ptg. paste which is ready to print.

Potassium carbonate is weak alkali.

Pgt. Paste recipe :

Vat dye – X % [Vatted out by equal amount of NaOH and Na2S2O4]

Starch tragacanth – 500 g

Thickening

Alkali potassium carbonate – Equal to amount of dye (H2CO3)

Rongalite – C - Equal to amount of dye

Glycerine - 50-75 gm.


B) Without Pre-Reduction :- This method is preferred for paste brand

dyes. The printing paste is prepared with same ingredient used in with

pre-reduction method. Only vatting is not done. Less care is required

is soluble in same container.

Ptg. Paste Recipe :-

Vat Dyes - X%

Glycerine - 100-150 gm

Starch Tragacanth - 500 gm

Rongalite-C - Equal to amount of dye


Potassium carbonate - Equal to amount of dye

10% dye apply on fibre; 30% wastage, 60% in steaming.

Purpose of printing paste ingredients :-

Vat Dye - To dye the fabric

Glycerine - As a hygroscopic agent

Starch-Tragacanth - As a thickner for suitable printing paste

K2G3 - Weak-Alkali used with easily reducible

dyes

Sod. Hydroxide - To make the vat dyes in soluble form.

In potash rogalite method alkali use potassium hydroxide and rongalite-C is

the reducing agents which gets activated as steaming temp. reducing.

1. Sodium sulphxylate formaldehyde (Rongalite-C)

2. During stg formaldehyde gets separated sodium sulphoxylate which is

the actual reducing agent.

Formaldehyde is used for increasing the stability of the compound at R.T.

During stg. process actual reducing agent which is sulphoxylate will be

released and vat dye will be solubilised by action of KOH/ reducing agent

and this solubilize dye will be applied to that fabric. Finally the material is

wash with H2O2 and after it wash the sample with soap and water

2) Potash Caustic Method

This method is given reliable results with most of the vat dyes. In this

case also the vat dyes is used with or without pre reduction. The reducing

agent is same rangalite-C. In this case same paste of alkali may be replaced

by using caustic-soda.

A) Without Pre-Reduction Ptg. Paste Recipe :

Alkaline Thickening – 500 gm.

Starch, British Gum K2CO3, NaOH, containing

B) With pre-reduction ptg. paste recipe :

Vat Dye - X%

British Gum Paste - 500 gm

Urea, Glycerine - 20 gm, 20 gm

K2CO3 - 100 gm

Rongalite-C - 160 gm

K2CO3 is weak alkali.

We have to keep in the steamer it is more ptg. paste, speed is less.

Caustic is strong alkali, caustic is very sticky in nature. So it takes

much time while washing. Handling of strong acids is difficult. When

caustic is touch with fabric then caustic is sticky when paste is prepared then

50% work is done and proper registration of paste on fabric 100% caustic is

not used because more water is used which don’t affort. So 50% caustic is

used.

Advantages:-

1. It is sticky in nature

2. Starch is mixed with British Cum. It has better flow properly.

3. Porosity of this is poor.

Advantage of Pre-Reduction:- Because in this case dye is added in the pre

reduced/dissolved from So 20-30% dye is immediately apply on the fabric

and rest of the dye goes to fibre during stg. So in this process more colour

value is achieved from the added dye.

Disadvantage:- Because the dye is in the pre-reduced form this may lead to

the uneven ptg. and unstable conditions for the ptg. paste.

Process :- 1) Print the material.

2) Partially dry the sample.

3) Steam the material at 100°C to 102°C for 3 to 5 mtr.

After the stg. the mat is followed by oxidation.

Purpose of oxidation of step is to reconvert the sol. form of dye into

insoluble form. The oxidation may be carried out by any of the following

process.

1) Air Oxidation :- This is cheapest and simplest to handle. But it is a

slow process. It sufft time is not given complete oxidation may not

take place.

2) Chemical-Oxidation :- Sodium perborates, H2O2 etc. may used as

oxidizing agent. It is a fast process. This is commonly used method.

After-Treatment:-

1) The cloth is rinsed and soaped at boil.

2) Then thoroughly wash the sample and dried. Soaping is done to

remove exhaust thickener film and residual chems.

Porocity :- Transfer the dye from the paste to fibre is called porocity.

Advantages:-

1) It has faster solubilisation than the first motor.

2) Chemical saving is more.

3) Fabric feel does not become harsher.

4) Colour Hue value is better.

3.3 PRINTING WITH AZOIC COLOURS (NAPHTHOL

COLOURS)

General about Naphthol colours

Azoic colours are also called Ice colour. There are light lemon or

yellow colouring matter. These colours are not readymade dyes. Because of

high degree and excellent brightness, easy of application and excellent

fastness properties (except rubbing). Azoic combination (naphthol +base)

are widely used in printing on cellulose fibre these are applied by dried ptg.

Style by four methods :-

a. Base printing method

b. Naphtholate printing method

c. Naphthol nitrite padding method

d. Naphthol nitrite printing method

Basic fundamental chemical :

(a) Naphthol :- Naphthol may produce different coloure with different

bases. Naphthols are Insoluble in water but at a solublised in presence

of NaOH.

(b) Diazotised base :- It is alkaline in nature.

Process of Diazotisation :- Conversion of water insoluble complex organic

compound into water solubile form.

c) Coupling :- Process of combining Naphthol and Diazotised Base

is called coupling to form Naphthol pigment.

Development of colour by the reaction of soluble naphthol and diazatised

base. Naphthol pigment are used to get blood red shade on tomato red shade.

Base printing method :-

Base + Dissolved Naphthol – Diazotised Base + HCl + NaNO2

Printing paste will be prepared mixing the diazotized base with a

suitable thickening paste. Cotton fabric is printed with this paste and dried.

Paste- Recipe

Base - X gm.

Concer. HCl - X/Z gm

Sodium Nitrite - X/Z gm

T.R.O. - 50 gm.

Starch Tragacanth - 500 gm or more

Sodium Acetate - 50 ml

Water - To adjust of viscosity

Acitic acid - 50 ml or more

(Before mixing) Diazotion of the base is carried out by adding sodium

nitrite and concentrated HCl at 0-4°C temp. allow it strength is 15 min. to

complete the process of diazodiation. A buffer solution made by a weak acid

and a weak acid salt cacidic acid and sodium acetate) are adding in the

printing part to maintain the pH on acidic side.

Purpose of Different Ingredient :-

1. Fast base :- Fast base is a colourless and applied on the fabric at in

the form of paste. It is converted into diazotized base with the help of

chemical.

2. HCl :- HCl is used to base is converted intoits diazotized base.

3. Sodium-Nitrite :- Sodium nitrite is another chem. Used to base is

converted into its diazotized base.

4. Starch Tracagonth :- Starch tracagonth is thickener is used to make a

workable paste.

5. Glycerine :- Glycerine act as a hygroscopic agent.

6. Acetic acid : Acetic acid and sodium is used as a Buffer.

Procedure :-

1) First insoluble naphthol is converted into its soluble sodium

naphthol with the help of NaOH.

2) Fabric is passed through the solution of sodium Naphthol.

3) After passed through the solution and then fabric is dried.

4) Secondly the base is converted into its diazotized base with the

help of NaNO2 and HCl.

5) And then the 3 mix all the ingredients with the help of stirrer to

obtained a suitable paste.

6) Print the material using screen printing.

7) After printing dry the sample when cool in takes place.

2. Naphthol printing method :- It is must remove the base printing.

Paste recipe :-

Naphthol - X gm

T.R.O. - 5-10%

Methylated spirit - 50 gm

NaOH 70 TW - 5-10%

Starch tragacanth - 500 gm or more


Procedure

1) Cloth is printed with the naphthol paste.

2) Then it is passed through a suitable diazotized fast base containing

NaCl and a diazostablised and after giving sufficient time to complete

coupling reaction it is rinsed.

3) The treated with sodium bisulphate solution then rinsed, soaped,

washed and dried.

Purpose of Printing Ingredient :

1. Naphthol AS – Naphthol AS is a colourless compound which is

applied on the fabric in the form of paste. Naphthol is converted into

its soluble sodium naphthalate.

2. T.R.O. :- It is act as a wetting agent.

3. Methylated spirit :- Methylated spirit is act as a solvent.

4. Sodium Hydroxide :- Sodium hydroxide is used to convert the

naphthol into its soluble sodium naphthol.

5. Starch – Tragacont :- This thickner is used to make a workable

paste.

6. Evator :- To adjust the viscosity.

Naphthol advantage over the base printing :-

1. No extra chemical wastage

2. Limited use

3. Time less required

4. Cost saving

5. No wear steam of material

3. Naphthol – Nitrite padding method :-

Previous method :-

Base + HCl + NaNO2 Diazotised Base at 0-4°C

Stable compound

Now we add NaNO2 in the sodium Naphthol instead of base colour.

Naphthol + NaOH Sodium Naphthol + NaNO2

For making stablise paste or stable liquor.

In this method Naphthlate and sodium nitrite (NaNO2) are taken in the

padding liquor. The solution cloth is placed with this solution.

After this cloth is printed with a thickened paste containing

hydrochloride of base, tartaric acid, lactic acid etc.

Paste- Recipe:-

Padding liquor :-

Naphthol - X gm

Methylated spirit - 5-10%

NaOH (70 TW) - 5-15%

NaNO2 - 25 gm

T.R.O. - 5-10%

Water - To adjust viscosity

Paste:-

Base - X gm

Starch Tragocanth - 500 gm or more

Tartric acid - 5-10%

Lactic acid - 5-10%

Concen. HCl - 0-5%

Water - To adjust viscosity

Procedure :-

1. Cloth is padded with Naphthol solution.

2. Print the cloth with base paste

3. Dried

4. Rinsed, Soaped, Washed and dried

5. Treat the cloth with sodium bisulphate.

4. Naphthol Nitrite printing method :-

In this method, the cloth is first printed with a thickening paste

containing Naphtholate and sodium nitrite and then developed in a solution

of hydrochloride of a fast base. The base of hydrochloride gets diazotized

and coupled with the naphthol at the printed portion, leading to the

formation of the azoic pigment. This method is suitable for producing small

designs only.

Paste Recipe :-

Naphthol - X gm

T.R.O. - 5-10%

NaOH - 5-15%

Hot water - To proper dissolution for maintain viscosity

Starch tragacanth - 500 gm

Sodium Nitrite - 5-10%

Dissolved water

Procedure

1. Cloth is printed with Naphthol printing paste.

2. Pass the cloth through base solution for development

3. Steaming for 5-10 min in a rapid ager.

4. Then cloth is rinsed with water soap at boil, washed and dried.

Process :

Print dry pass through after treatment steaming base solution

Advantages of Naphthol printing method over base printing method:-

1. The prints are produced by a simple after treatment.

2. Since the naphthol is printed at required area of the cloth, the ground

is kept whitened and therefore it is easier to produce better white

ground.

3. There is saving of chemicals in the naphthol method. Since in the

other method. Naphthol is applied to the whole cloth and then it is

removed from the ground after printing with the diazotized base.

4. There is possible to produce deep and pale shade by naphthol printing

paste which contains different concentrations of naphtholes.

Unit 4– Printing of cotton fabrics with Pigment Colours

4.1 PIGMENT PRINTING

Ptg. of cotton fabric by pigment colours by direct style.

Pigments

Pigments are the special type of colourent which are neither soluble

nor can be made soluble by adding other chemicals. But these are the type of

colourent which are most widely use for printing of tex. mat. Because these

can be applied to variety of fibre mats with a very simply process.

These colours gives satisfactory fastness properties such as washing,

light, but rubbing fastness properly no so good.

There are applied on the fabric with the help of the chemicals (cross

linking chemical) and are mech. fixed on cloth.

Principle of pigment printing :- Principles of the pigment printing is

just similar to fixing of a stamp on a paper with the help of a transparent

adhesive or with the help of adhesive tape.

A transparent layer is made on the stamp and it serves two purpose.

i) It blinds the stamps with the surface on the paper. Similarly,

various ingredients present in the printing paste. Perform the

function of cello tape there by making the pigment on the fabric

sample.

ii) It protects the stamp from damage by addition of water as

moisture.

Ingredients of pigment printing paste :-

i) Pigment emulsion :- Pigments are not soluble in water. They are

converted into emulsion.

So an emulsifier is used to dissolve pigments.

Emulsion :- 20% water + 8-10% oil or oil + water

Kerosine oil 70% and water 10% is used. We choose water in oil

emulsion and these are applied to these emulsion. A mixture of oil water,

wetting agent is mixed with high speed stirring.

This gives a emulsion.

Emulsion paste :-

1. Pigment emulsion oil 60-80%, water 20-30%

2. Thickner (sodium alginate), CMC chemicals (Auxillaries).

3. Water

4. Emulsifying agent

Pigment emulsion :-

1. Oil - 60-70%

2. Water - 20-30%

3. Emulsifier agent - 5%

4. Pigment power - X % gm.

5. Wetting agent - 1-2%

Auxillaries :- Chemicals

Binder - 25-30%

Fixer - 5% max.

Catalyst diammonium - 1-2%

3) Binder :- These are cross linking chemicals which after treatment

at a higher temperature get cross linked and form a transparent

layer on the surface of the pigment particle like a adhesive type.

Polyvenyl-aceate was considered a good binder.

4) Fixer :- It is another cross linking chemical infact it is an initiater

of the cross-linking reaction between the binder molecules.

a. Which form a transparent layer on the surface of pigment

particles.

b. It binds the pigment particle with fabric surface like a adhesive

tape.

c. Binder are high molecular wt. film forming agent produces by

polymerization of simple monomerous present in the printing

paste.

d. After evaporation of the solvent (oil) a thin coating of film is

produce which cover the printing particles and got adhesive on

the fabric’s surface.

Following monomers are used as binder

1) Derivative of Acrylic-Acid

2) Butadiene

3) Vinyle acetate, Urea, formaldehyde, metamine, and other

simmilliar products are used as fixer.

4. Catalyst :- The function of catalyst is to increase the rate of reaction.

In this case of pigment printing to increases the rate of polymerization

of the binder and fixer molecules as well as between the binder and

cellulose fibre. One of such type of catalyst is Ammonium

sulphocyanide which increased acidic condition zinc nitrite is also

catalyst.

5. Acid librating agent : We add some acid librating agent in the

printing paste. This is used in during steaming.

6. Thickening past or thickening ingredients :- Sometimes a thickner

is also required to increase the viscosity of the paste.

Another purpose is to maintain the moisture in printing paste.

Approximately 0.5% of the total made can be used as thickening paste.

1. Sodium alginate

2. Carboxy methyle cellulose

3. Cellulose pextrin

7. Emulsion : A water in oil emulsion fixer, pigment or pigment

particles. So a great water in oil emulsion is required for combining

and fixing in the paste. Kerosene oil, emulsifier make emulsion.

8. Emulsifying agent :- these are must used in emulsion adhesives.

They serves an important work in emulsion process.

Printing paste recipe

i) Pigment emulsion - 10-15%

ii) Binder - 30%

iii) Thickner - 10-15%

iv) Water - To adjust the viscosity

MECHANISM OF PIGMENT PRINTING

Emulsion of water in oil acts as a medium of the printing ingredients.

This emulsion plays an important role in between coloured particles, binder

and fixer molecules which are otherwise not soluble in water.

Only all these are mixed up in the prescribed ratio in the emulsion and

stirred at vigorously.

Material is ptd with the paste. During curing process, binder

molecules are polymerized with the help of fixer or catalyst make a

transparent layer on the pigment particles present on the print and fixed the

print on the surface of the fabric mechanically.

This is similar to fixing a stamp on the paper with the help of a

transparent cello-tape.

Binder CH2 – OR – HO Cellulose

Binder CH2 – O + Cellulose

Where R is CH3 or H.

PROCEDURE OF PIGMENT PRINTING

Process :-

1) Make the pigment printing paste by the help of required chemicals

and work out a smooth paste having proper viscosity.

2) Print the cotton fabric with this paste.

3) Dry the material.

4) Cure the ptd. and dried materials at a temp of 160°C-170°C for 5-10

mtr.

5) After this the material is thoroughly washed, soaped at boil followed

by washing and drying.

Advantages :-

1) Pigment colours are can be used for all type of fibre e.g. natural fibre,

jute, silk, synthetic materials and blended materials etc.

2) This produce economically printing.

3) Fastness properties are good to excellent.

4) App. Procedure (Print – Dry – Cure) is very simple and does not

require any special after treatment.

5) Complete range of shades is available in printing with pgts.

Disadvantages :-

1) In certain colours, light fastness and rubbing fastness is not

satisfactory. This can’t be improve.

2) In some duplicate woolen fabric like wool or its blends harshness

may be produced in print. However, this problem can be minimize

by softening agent.

Ptg. with aniline black

Principle :- Aniline black can be oxidized in stages to a final jet black

shades on the fabric.

The process of production of aniline black on a cotton fabric by

dyeing or by printing.

Printing involves the application of aniline as fabric salt along with

sodium chlorate and potassium ferrocynite etc.

It is then followed by drying steaming and chroming. This steaming or

ageing is carried out in a special ager.

Steamer in which followed proversions.

1. Rapid removal of hydrochloric acid

2. A most hot atmospheric should be there.

4.2 PRINTING OF PTHALOCYNINE DYE

Introduction

Thalocynine pigment and dyes are obtained as a dark blue impurities,

which was observed while doing a chemical reaction of ammonia (g) with

molter phthalic anlydride kept in an iron vessel. This blue pigments are

sparated from the reaction mixture and a new type of organic compound

with one markable property born. This reaction lead to the invension of

thalocynine dye. Later on copper vessel are used in place of iron vessel are

copper blue pigment cellow copper phalocynine (CPC).

Property :-

Thalocynine colour was birllent blue shade with excellent fastness to

light, heat acid and alkali are used widely in various fields as printing inks

for plastic, rubber or cloth etc. They have various used.

Alcian blue dye :-

Alcian blue dyes are solublised CPC which are introduced by the

company ICI. Later on with experiment they introduced seven colour in

alcian series four not blue colour, two no colour and one yellow colour.

These were called onium dye.

PRINTING WITH THELOCYNINE BLUE:-

Printing paste may be prepared :-

Alcian blue pigment - X gm.

Starch trgacanth paste - 50% or more

Solubilising agent (lactic acid) - 3 x or 10%

Hydroscopic agent (glycerine) - 5-15%


Purpose of paste ingredients :-

(i) Lactic acid :- It is used as solubilising agent.

(ii) Glycerine or any product :- It is used as a hydroscopic agent during

steaming.

(iii) Alcain blue pigment :- To print the material (cotton)

(iv) Starch tragacanth :- To make workable paste.

Process :- Print dry steam

Procedure :-

Print the material with the paste followed by steaming lactic acid

maintain the dyes insoluble for better pentedition into the fibre. Glycerine

provided acts as a solvent disterising agent for the dye along with hygro

agent. Which creates a local dye bath for the absorb dye and help printing

the material.

Steaming is a essential during to fixation (insolubisation). Sodium salt

sulphuric acid like sodium dichromate converted the soluble form. Steaming

time are 5-10 min under normal conditions. Sodium acetate, trisodium

phosphate and trihydrogen phosphate are other chemical. Which can be used

as anionic product for fixation of dye.

Thanks .Rest in progress………..

Mandeep Nagpal

Lecturer Textile Processing

Govt. Polytechnic Hisar

PRINTING OF TEXTILES · 2018-04-10 · During the paste preparation all other chemicals, dyes, thickening paste are mixed together. But dissolved soda ash, which is for the fixation

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