Transfer Printing

A brief discussion on transfer printing in textile industry with its different types of application method.

1. Prepared by Md. Asiqul Alam B.Sc in Textile Engineering Port City International University Chattogram , Bangladesh Transfer Printing

2. Contents Introduction to Transfer Printing Sublimation Transfer Melt Transfer Film Release Transfer Wet Transfer Advantages, Disadvantages and Limitations of Transfer Printing

3. Introduction to Transfer Printing

4. Transfer printing is the term used to describe textile and related printing processes in which the design is first printed on to a flexible non-textile substrate and later transferred by a separate process to a textile. It may be asked why this devious route should be chosen instead of directly printing the fabric. The reasons are largely commercial but, on occasion, technical as well and are based on the following considerations. Designs may be printed and stored on a relatively cheap and non-bulky substrate such as paper, and printed on to the more expensive textile with rapid response to sales demand. The production of short-run repeat orders is much easier by transfer processes than it is by direct printing. What is Transfer Printing?

5. The design may be applied to the textile with relatively low skill input and low reject rates. Stock volume and storage costs are lower when designs are held on paper rather than on printed textiles. Certain designs and effects can be produced only by the use of transfers (particularly on garments or garment panels). Many complex designs can be produced more easily and accurately on paper than on textiles. Most transfer-printing processes enable textile printing to be carried out using simple, relatively inexpensive equipment with modest space requirements, without effluent production or any need for washing-off.

6. A great many methods of producing textile transfer prints have been found. Many of them exist only in patent specifications but several have been developed to production potential. They may be summarized most conveniently as below: Sublimation transfer: This method depends on the use of a volatile dye in the printed design. Melt transfer: The design is printed on paper using a waxy ink and a hot iron applied to its reverse face presses the paper against the fabric. Film release: This method is similar to melt transfer with a little difference. Wet transfer: Dye transfers by diffusion through the aqueous medium. Types of Transfer Printing

7. Sublimation Transfer Printing

8. Sublimation is the name for the chemical processes which is a solid object is changed into gas without first becoming a liquid . In recent years Sublimation Transfer Printing has become mostly used and economic printing process. It depends on the usage of a volatile dye in the printed design. When the paper is heated the dye is preferentially absorbed from the vapour phase by the textile material with which the heated paper is held in contact. What is Sublimation ? Sublimation Transfer Printing :

9. Dye sublimation is relatively easy way to print design onto garments, compared to other methods like screen printing, embroidery etc . All that’s needed is : A dye sublimation printer Sublimation paper Photo processing software A heat transfer press A digital camera or scanner to transfer design Equipment needed for Sublimation Transfer Printing :

10. Dye sublimation is done using a digital image , a dye sublimation printer and dye. The image is transferred to dye sublimation paper and the ink is transferred to the fabric. The image retain the digital quality & is permanently embedded into the fabric. Then the fabric is washed, dryed and worn over and over. How it is done?

11. Work shirts and jackets. Promotional Items. Merchandised for valued customer. T-shirts and hats. Uniform for EMTs , Firefighters , Police and municipalities. Application :

12. Melt Transfer Printing

13. This method has been used since the 19th century to transfer embroidery designs to fabric. The design is printed on paper using a waxy ink, and a hot iron applied to its reverse face presses the paper against th e fabric . The ink melts on to the fabric in contact with it. This was the basis of the first commercially successful transfer process, known as Star printing, developed in Italy in the late 1940s. It is used in the so-called ‘hot-split ’ transfer papers extensively used today in garment decoration. What is Melt Transfer Printing? Melt Transfer Printing

14. Melt Transfer Diagram

15. The ink layer of the transfer is based on dyes and waxes. The ink layer is embedded in the fabric by melt and pressure, and part of the ink is transferred to the fibers and then post-treated according to the properties of the dye. When the melting method is employed, a large pressure is required and the transfer rat of the dye increases as the pressure is increases. Melt Transfer Printing Process

16. Film Release Transfer Printing

17. As the name implies, film release deposits the printed image as a virtually coherent film on the textile material. Such systems have been used for several years with great success worldwide for the decoration of garments; their use for printing continuous web fabrics, which have to meet different criteria, has not so far proved commercially viable, although the technical problems presented are well understood. What is Film Release Printing?

18. This process is similar to melt transfer with the difference that the design is held in an ink layer which is transferred completely to the textile from a release paper using heat and pressure. Adhesion forces are developed between the film and the textile which are stronger than those between the film and the paper. The process has been developed for the printing of both continuous web and garment panel units, but is used almost exclusively for the latter purpose. In commercial importance it is comparable with sublimation transfer printing. Film Release Printing Working Process

19. Film Release Printing Diagram

20. Two main methods are used for the production of transfers. One method is to print on to a release paper, usually one that is coated with a Werner complex, using a semidrying lithographic ink system and then to blotch screen print over the image using a white or grey plastisol backing coat. Alternatively the image can be directly printed using fine screens and plastisol process inks. The image layer is thin and does not have high covering power, so an additional plastisol backing layer is normally required. Both methods enable images of high photographic quality to be produced. Film Release Printing Methods:

21. Wet Transfer Printing

22. Water-soluble dyes are incorporated into a printing ink which is used to produce a design on paper . The design is transferred to a moistened textile using carefully regulated contact pressure. The dye transfers by diffusion through the aqueous medium . What is Wet Transfer Printing?

23. Wet transfer-printing machine ( DewPrint )

24. Steps of Wet Transfer Printing Process A wet transfer printing process for fabrics is known which comprises the following three stages. 1 st: The pattern / design is printed on a special grade paper by paper printing or modified textile printing machine 2 nd : The fabric is impregnated with a mixture containing water, dye carrier, dye fixation, catalyst etc. at the boiling temperature of the bath. 3 rd: The transfer of printed design/ pattern from the paper to textile substrate is effected by forming a sandwich of printed paper and impregnated wet fabric followed by application of required pressure and temperature for a fixed time of contact in suitable Machine Specially developed for this purpose.

25. Advantages, Disadvantages and Limitations of Transfer Printing

26. The capital cost of the equipment is low. Space required is also small. A skill printer is not required through careful control of temperature and pressure. A clear and sharp definition of all objects is possible. The proportion of sub-standard quantity is as low as 20% Since the printed fabric does not required any after treatment, it does not contribute to water pollution problem . Advantages of Transfer Printing

27. It gives good prints on well prepared knitted goods. No adverse effect on fabric’s feel and luster. It allows excellent dye penetration into the fiber ( because transfer takes place at very high temperature). Steaming , Washing, drying etc are not necessary. Quicker reaction to changes in fashions. Advantages of Transfer Printing

28. There is some restriction of the production of deep shade High temp and pressure is required Once printed cannot be corrected Only limited dyestuff can be used for transfer printing Lower production speed due to existing transfer calendars Storage of large quantities of paper over prolonged period of time is a risk. Disadvantages of Transfer Printing

29. Not applicable to all fiber specially which cannot stand under required temperature and pressure. The print paper is not available. Limitations of Transfer Printing

30. Thank You