The textile industry has been known to use a lot of chemicals for the purpose of printing and processing. For decades plastisol inks have been utilized for screen printing of garments and pre-cut textile applications. Since these are essentially Polyvinyl chloride (PVC) based chemicals, they are highly toxic in nature and hence have raised very serious environmental concerns within the industry.
The good colour opacity, affordable pricing, and high productivity rates have been the reason why they have been popular among textile printers all around the globe. PVC based chemicals contain phthalates, which are added to transform a hard plastic into a rubbery soft form, by letting long polyvinyl molecules slide against each other, instead of binding rigidly together. Phthalates is a carcinogenic substance and is extremely hazardous to foetuses and infants. Hence many brand owners, apparel retailers, and non-government organizations have been anti-PVC based inks, and owing to the growing awareness, and demand for eco-friendly inks, have resulted in adopting new alternatives.
One such option has been the use of water based inks for screen printing in the textile and apparel industry. Such inks use water as the basic solvent. There are two main types of water based inks being used currently which are traditional ink and discharge ink. The traditional ink also known as the air dry ink seeps into the fabric and binds with the fibres leaving good colour fastness and wash ability. The discharge ink is used to remove the original dye from the apparel and replaces it with a particular colour or pigment. The discharge inks free of formaldehyde formulations are also available for a pollution free environment.
Water based inks are easy on the pocket in comparison to solvent based inks but yet provide the same quality, adhesion, and the gloss of PVC based inks. There is a common misconception pertaining water based inks, which is that they have just water. While in reality they comprise of pigments, binders, thickeners, and eco-friendly solvents. Also water based inks unlike plastisol do not need harmful solvents for the cleaning process. The screens after printing can be cleaned using water.
Many consumers prefer a soft finish where the print soaks into the surface of the fabric and the ink film cannot be felt, which can be achieved with water based inks. However, the screen printing process with water based inks requires an altogether different set of skills, tools, supplies, choreography, speed, and experiences.
The shelf life of water based inks longer than the conventional inks thanks to manufacturers who have devised a technology to encapsulate water in the ink in a way that it does not evaporate until it is printed. Available and sold in the textile chemical markets just as traditional plastisol like colours or underbases, water based inks have thicker viscosity yielding greater opacity on finished prints.