Introduction to Textile Printing-1.pptx

Introduction to Textile Printing

1. Mohammad Shohag Lecturer, DoWPE BUTEX Email: [email protected] WPE: 311 Wet Processing- II Part-A: Textile Printing

2. Curriculum Details Credit of the course is 3. Hour/Week 4. Total Week 10. Total Hour 40 (Part-A 20 Classes & Part-B 20 Classes). Part A(Textile Printing) Part B(Textile finishing) Introduction to Printing. Thickener Style of Printing. Printing Methods/techniques Special printing method. Printing with different dyes/pigment Introduction to Finishing. Physical or Mechanical Finishing. Chemical Finishing. Special Finishing. Part A: Mohammad Shohag Part B: Humayra Akhter Himu

3. MARKS ALLOCATION 1.CLASS ATTENDANCE =8 2.CLASS TEST (5×4) =20 3. FINAL =72(Part A-36, Part B-36) TOTAL =100

4. Textile printing by Leslie W C Miles. Principle of Textile Printing by Asim Kumar Roy Choudhury Technology of Printing edited by Prof. V. A. Shenai. Reference Book:

5. Chapter-1: Introduction to Printing

6. Table of Contents Definition of Printing Objectives of printing Difference between dyeing and printing. Chronological development of Printing machinery History of printing Steps of textile printing process using dye Functions of print paste ingredients with example.

7. What is Textile Printing? Textile printing is the most versatile and important of the methods used for introducing color and design to textile fabrics. The term ‘’textile printing’’ means the localized application of dyes or pigments and chemicals by any method which can produce particular effect of color on the fabric according to the design. In printing dye/pigment and chemical are applied in paste form, this paste are created with dyes/pigments, thickener, other necessary chemicals etc. Printed fabric can be identified by looking at back side of fabric where there is no design or color as face side.

8. Objectives of Printing To add color on localized area. T o produce various attractive designs. Allows greater design flexibility over other system. Inexpensive product compared to other system. C ombines art, engineering, and dyeing technology to produce images that existed only in the textile designer’s mind.

9. Block Printing Technology

10. Roller Printing Technology

11. Screen Printing Technology

12. Transfer Printing Technology

13. Digital Printing Technology

14. Chronological Development of Textile Printing Machine Method Period Origin Block Ancient China Roller printing 1785 Scotland Manual Screen 1900 England Auto flat bed Screen 1940 Switzerland Rotary Screen 1963 Portugal Transfer Printing 1968 France Inkjet/Digital printing 1990 USA

15. Historical Perspective of Textile Printing Fabric printing is not a new process; in fact, it’s been around for many centuries.   Ancient civilizations used color and design to set themselves apart.   Textile printing is an ancient art, from the 4th and 5th centuries BC.  The first commonly used textile printing method originated in China, where examples of wooden block printing have been discovered. Block printing  is the process of designing fabric using some form of carved material generally been wood or copper, but on occasion rubber and even other materials have been used, and are still using today. At the beginning of the 17th century, the East India Company began to ship block printed cotton fabric to England. But they unable to produce the designs demanded by British, so British people implement printing in their places with their own specific patterns, It was near about 1676 they established the first print works in England, near London.

16. Historical Perspective of Textile Printing Later, in the 18th century (near about 1785),  a printing technique using rollers or cylinders emerged.  This is a process whereby the fabric is carried along a rotating central cylinder and pressed by a series of rollers, each of which is engraved with the design. Each roller is supplied with a different color through the feed rollers, and some roller printing machines were able to print as many as 6 colors at a time, making them much faster than the block printing process. The 20th century marked the arrival of the modern silk-screen printing process.   In the mid-20th century, multi-color rotary screen-printing enabled screen printing on a large scale  and at a faster rate, making it more economical. In 1750s Transfer printing invented for decorating  pottery  or ceramic items. In the middle of 20th century it becomes enormously popular in other sectors like textiles, home album, tourism etc. Today, we have digital textile printing, which uses  computer-controlled lasers to inject the ink directly into the fabric.  This allows the printing of very detailed designs extremely quickly and efficiently. 

17. Printing Dyeing Steaming is not required on dyed fabric Steaming is used in the printed fabric for fixation More time is required Less time is required W hole fabric is uniformly covered with one color O ne or more colors are applied only to defined areas to obtain the desired pattern.  No use of thickener Thickener is used Huge amount of water is required Less amount of water is required Fiber, yarn and fabric are dyed Mostly fabric is printed but now a days yarn are also printing. Dyeing is a thorough coloration process of textile materials in which dyes and pigments are applied from a solubilized medium to the textile materials. Printing is the localized application of dyes and pigments from a solubilized or a insolubilized medium to the fabric surface. Color is applied in form of solution Color is applied in form of thick paste 1 2 3 4 5 6 7 8 Difference between Dyeing and Printing

18. Grey Fabric Preparation of Fabric Design Selection Preparation of print paste Printing on the fabric by block, roller, screen Drying of printed fabric Steaming of printed fabric Washing and Soaping Final dry Steps of Textile Printing Process Artworks received from buyer to follow design Design transfer to blocks/rollers/screens manually or by exposure of light sensitive coating Color Separation

19. Dyes or Pigments Thickener Wetting agents Solvent/dispersing agents Defoaming agents Oxidizing agents Reducing agents Catalyst and oxygen carrier Acids and Alkalis Carrier Swelling agents Hygroscopic agents Functions of print paste ingredients with example.

20. Dyes or Pigments: Produce color effect on the fabric Achieve required shade Attraction of dyes to the fabric due to presence of auxochrome. Example: Direct dyes, Reactive dyes, Vat dyes, Acid dyes, Basic dyes, Disperse Dyes, Azoic dyes and Pigments. Thickener: To give required viscosity to the printing paste. To prevent premature reactions between the chemicals contained in the print paste. To hold the ingredients of the print paste on the fabric. Example: Starch, Na-Alginate, Guar gum, British gum, Locust bean gum, Gum arabic, Gum tragacanth, CMC(carboxy methyl cellulose) etc. Functions of print paste ingredients with example.

21. Wetting Agents: To reduce the surface tension of water allowing the dyestuff for easy penetration into fabric. To wet the fabric as well as dissolve the dyestuff in the paste. To obtain smooth paste Example: Turkey Red Oil(T.R Oil), Olive oil, Castor oil, Glycerin, Almond oil, Lissapol N. animal oil etc. Solvents or dispersing agents: To prevent aggregation of the dye molecules in the highly concentrated paste. To spread dye molecules evenly in the paste. To increase solubility of the dyes. To get bright and prominent print design. Example: urea, Glycerin, di ethylene glycol, thio diethylene glycol, acetone, alcohol. Functions of print paste ingredients with example.

22. Defoaming agents: To prevent the foam generation during printing. To make proper printing shade. Example: Silicone defoamers, Sulphated oil, Perminal KB, Emulsified pine oil. Reducing Agents: To make the insoluble dyes to soluble form. Used for reduction of different dyes. Used mainly in discharge style printing. To destroy color from the ground of fabric. Example: Rongalite C, sodium hydrosulphite.. Oxidizing agents : To develop the final color during steaming or in the after treatment. To assist dye fixation. Example: Potassium chlorate, sodium chlorate, sodium nitrate, Na or K dichromate, ammonium chloride etc. Functions of print paste ingredients with example.

23. Mild Oxidizing agents: In case steaming of azo dyes, the prints tends to reduce which may result in loss of color value and destruction of dyes, to prevent this problem mild oxidizing agents are used. Example: Ludigol, Resist salt. Catalyst and Oxygen Carrier: To prevent fiber damage during steaming. Accelerate the final color development by oxidation. Reduce the risk of oxidation. Example: Copper sulphide, Potassium ferrocyanide, ammonium vanadate. Acids and Alkalis: To maintain P H To develop the color on fabric To fix dyes on fabric permanently To fix pigments and binders on fabric permanently. Example: Acids- organic acid, ammonium chloride, diammonium hydrogen phosphate, ammonium sulphate, ammonium nitrate etc. Alkalis- sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium silicate, trisodium phosphate, di sodium hydrogen phosphate. Functions of print paste ingredients with example.

24. Swelling agents: Helps to swell the fiber structure. To increase the intermolecular space of fiber. Helps to penetrate the dye molecule inside fiber space. Example: Phenol, polyethylene glycol, Diethylene glycol diacetate(DEGDA), Ethyl lactate[CH 3 CH(OH)COOC 2 H 5 ]. Carrier: Works like swelling agents. Lowering the glass transition temperature(tg) thus promote molecular chain movement and create free volume. Example: phenol, ortho phenyl phenol, para phenyl phenol, dichloro benzene. Hygroscopic Agents: Absorb moisture from air. To assist dye fixation. Facilitate subsequent washing off. Example: Urea, Glycerin etc. Functions of print paste ingredients with example.

25. Problems: What is textile printing? State the functions of different print paste ingredients with example. Write down the various stage of textile printing. Mention the functions of oxidizing agent, alkali and urea in a print paste. Differentiate between dyeing and printing. Mention the functions of defoaming agents, hygroscopic agent and dispersing agent in a print paste. Mention the chronological development of printing era.