Textiles; printing, dyeing and other finishing processes (Part I) Dr Celina Jones Lecturer in Fashion Technology [email protected] M A T S 6 7 1 2 1 Aim of Today’s Lecture Introduce you to textile finishing manufacturing techniques and basic production processes. In particular, we will be focusing on technologies within the field of fabric enhancement (printing) and other processes. Introduce a range of finishes for textiles, detailing their purpose and method of application M A T S 6 7 1 2 1 Structure of the Lecture 25 Briefly recap Week 1 Textile Printing and Coloration Finishing Processes Minutes Before dye is applied Finishing Processes 25 Before dye is applied Minutes After dye is applied Sublimation Printing 25 Thermochromics Minutes Pigments and Binders Finishing R E V I S I O N - L A S T W E E K Textile Fibres Synthetic Protein Cellulosic Disperse Acid Direct (Polyester) Acid (Nylon) Reactive Finishing COLOURATION Applying Dyes to Textiles Finishing COLOURATION Processes with Dyes Dye Application Cover next week Dye Bath Print Paste Print Ink Using Silk Digital Screen Printing Printing Finishing COLOURATION Processes: Dye Bath Processes before the application of dye: Finishing PHYSICAL RESISTS Shibori Japanese name, deriving from the verb ‘shiboru – to wring, squeeze and press’. Often referred to as tie-dye. Wells K. 1997 PHYSICAL RESISTS Shibori https://www.wgsn.com/content/board_viewer/#/24694/page/1 Finishing PHYSICAL RESISTS Shibori A process of blocking the dye from the fabric, using string, objects, folds, stitches,etc. Finishing PHYSICAL RESISTS PHYSICAL RESISTS ShiboriBatik Can use blocks of wood and clamps Finishing PHYSICAL RESISTS PHYSICAL RESISTS Shibori Creates geometric repeats http://images.dharmatrading.com/images/public/instru ctional/ikatshibori/itaje.jpg http://3.bp.blogspot.com/-LlNalsBsGZc/Tq9yVDcXknI/AAAAAAAANAc/e_l7MYr4PVc/s1600/IMG_0092.JPG Finishing PHYSICAL RESISTS Batik A process of blocking the dye from the fabric. Wax was used traditionally as the resist, but today chemicals can be used. http://www.barkclothhawaii.com/fabrics/detail/d20batik.jpg http://www.unesco.org/culture/ich/img/photo/thumb/00946-BIG.jpg Finishing COLOURATION Chemical Resists Prevent the fixation mechanism from operating. For example, a nonvolatile acid will prevent the alkaline fixation of reactive dyes on cellulosic fibres. Ingamells 1993 https://fashion2apparel.blogspot.com/2017/04/printing-styles.html Finishing COLOURATION Chemical Resist Printing A process before the application of dye: Undyed Fabric Finishing COLOURATION Chemical Resist Printing A process before the application of dye: Printing paste with Chemical resist agent Finishing COLOURATION Chemical Resist Printing A process before the application of dye: Chemical Resist Print Finishing COLOURATION Chemical Resist Printing A process before the application of dye: Finishing COLOURATION Chemical Resist Printing A process before the application of dye: Please go to kahoot.com on your laptop or the ap on your phone… Finishing COLOURATION Processes: Dye Bath Processes before the application of dye: Finishing PHYSICAL RESISTS Ikat A process of blocking the dye from the yarns. Warp and/or weft yarns are tied together in bundles to make the desired pattern. http://lillstreet.com/blog/wp-content/uploads/2014/02/Warp-ikat-being-tied.jpg Finishing PHYSICAL RESISTS Ikat They are then dyed and the ties undone. http://www.prioritywindows.com/images/blog/ikat-blue.jpg http://static.squarespace.com/static/527c3236e4b0c84d7aac73fa/t/5350a780e4b06683005fcb3 e/1397794689624/Aligning-Yarn-Ikat.png Finishing PHYSICAL RESISTS Ikat The yarns are then threaded through the loom http://www.binichic.com/blog/wp-content/uploads/2012/02/1_llengues_vicencs_binichic1.jpg http://4.bp.blogspot.com/-4xmVq_pt8f0/T3NJmxWN13I/AAAAAAAAG3k/7dwEGQj9hDQ/s320/warped- tateyokopgasuri-300x200.jpg Finishing PHYSICAL RESISTS Ikat Finishing COLOURATION Discharge Printing A process after the application of dye: Intricate print on a coloured fabric The print can be white or a colour; the latter referred to as ‘illuminated discharge printing’ https://media.seamwork.com/2016/04/Melissa_Dettloff-09-discharge- printing-1024x680.jpg Finishing COLOURATION Discharge Printing A process after the application of dye: Ground shade of the fabric must be sensitive to the discharge agent in the print paste, (i.e. be dischargeable) to give ‘white appearance’. For example, if the discharge agent is alkali then alkali sensitive dyes must be used in the ground shade Finishing COLOURATION Discharge Printing A process after the application of dye: Dyed Fabric Finishing COLOURATION Discharge Printing A process after the application of dye: Printing paste with discharge agent Finishing COLOURATION Discharge Printing A process after the application of dye: Discharge Print Finishing COLOURATION Devoré Printing Can be a process after the application of dye or used on undyed fabrics. Removing fibres instead of dyes: Printing process of removing cellulose from a dual or multi-fibre fabric under the influence of heat and acid The fabric is specially constructed for the purpose so when the cellulose is removed there remains a skeleton of non-cellulosic yarn to hold it together. A number of acidic chemicals have been used including sodium bisulphate, sulphuric acid and aluminium sulphate. Finishing COLOURATION Devoré Printing An example of a typical colourless devoré paste: 15g Aluminium Sulphate 60g Indalca PA/3R (6% stock) 5g Glycerine (glycerol) 20g Water Finishing COLOURATION Sublimation Printing Transfer printing technique A dry transfer process (does not use water) Uses disperse dyes Called sublimation printing as the disperse dyes siblime when heated. https://oss.adm.ntu.edu.sg/bren0016/tag/transfer-printing/ Finishing COLOURATION Sublimation Printing Can be applied by painting onto paper or inkjet printing Fabric and paper are put in heat press (200°C) 30-40 seconds Advantage is that no printing paste is applied to the fabric; no washing off is necessary. https://www.pinterest.co.uk/fabricprint/heat-transfer/ http://hot-textiles.blogspot.com/2011_08_01_archive.html Finishing SMART TEXTILES Phase Change Materials (PSMs) Through the use of textile finishes, textiles can respond to changes in the temperature of the environment. Microencapsules containing phase change materials (PCM) can be added to fabrics. ⬆ temp. increase the encapsulated chemical melts and absorbs the heat. ⬇ temp. falls PCMs solidify and heat is http://www.centexbel.be/files/month/m released, providing heat effect. atrastijkbreisel-met-pcm-capsules- peultjes_0.png http://wcec.ucdavis.edu/wp-content/uploads/2012/10/PCM_hero.jpg Finishing COLOURATION Thermochromics Microencapsulated dyes can be used (thermochromics) which display a change in colour with a change in temperature Finishing COLOURATION Thermochromics Finishing COLOURATION Thermochromics Thermochromics can be applied to textiles in a variety of ways: 1. Pad mangle Finishing COLOURATION Thermochromics 2. Silk Screen Printed Finishing COLOURATION Thermochromics Thermochromics have been used in the past for novelty items, but today they are being used for medical textiles too. Please go to kahoot.com on your laptop or the ap on your phone… Finishing COLOURATION Pigments Colorants that are insoluble in the dye bath Will not form ‘bonds’ with the textile material Pigments have a ‘crystal’ structure http://plentyofcolour.com/wordpress/wp- content/uploads/2011/03/plentyofcolour_holi16.png Cannot penetrate textile fibres and reside on the surface of the fibre Finishing COLOURATION Pigments 1. Melt Spinning The pigment is incorporated with the polymer chips Extruded through spinneret to form filament The pigment is uniformly distributed throughout the fibre Finishing COLOURATION Pigments 1. Melt Spinning Pigment used needs to be heat stable (temp. in spinneret head) Cooled fibre – locks pigment inside solid fibre http://www.wacker.com/cms/media/images/mark ets_1/textile/process_aid_IMG_230.jpg Finishing COLOURATION Pigments 2. Pigment Printing Consists of pigment, polymer binder, thickener, emulsifiers, softeners and crosslinkers Simple technique – print, dry and heat cure http://thinkingflowers.files.wordpress.com/2011/06/dye.jpg Finishing COLOURATION Pigment Printing Heat Cure Dry Print Finishing COLOURATION Pigment Printing A puffing agent can be added to the pigment printing paste, creating a raised 3D effect in the fabric. When the puff pigment print is subsequently dried and cured, the puffing agent in the print expands, thereby creating raised, http://www.optiger.cz/img/print_efekty.jpg three-dimensional designs on the surface of the fabric. Finishing COLOURATION Pigment and Dye Comparisons Pigments are cheaper than dyes. Pigments have high light fastness, Dyes have variable light fastness. Wash fastness depends on pigment location. Pigment inside fibre has high fastness (melt spun) Wash fastness is variable depending on the dye. Finishing COLOURATION Pigment and Dye Comparisons Pigment/binder applications can adversely affect fabric handle, pigment inside the fibre has no effect on the handle. Pigment/binder applications on surface of textiles can affect the fabric lustre. http://www.wgsn.com/content/board_viewer/#/51511/page/4 M A T S 6 7 1 2 1 Recommended Reading Textiles and Fashion: Materials, Design and Technology, Woodhead Publishing Series in Textiles Sinclair, R. (2015) Chapter 19 – Fabric Finishing: Dyeing and Colouring Chapter 20 – Fabric Finishing: Printing Textiles M A T S 6 7 1 2 1 Further Reading Synthetic Fibre Dyeing, edited by Chris Hawkyard, Society of Dyers and Colourists, 2004 Colour for textiles, A users handbook, Wilfred Ingamells , Society of Dyers and Colourists 1993 The Chemistry of Colour Application, by R.M. Christie, R. R. Mather and R. H. Wardman, Blackwell Science , 2000 Fabric Dyeing and Printing by Kate Wells 1997. Published by Conran Octopus Limited Textile Printing – Leslie Miles, Society of Dyers and Colourists, 2003. .