Screen printing on cotton fabric using chitosan and alginate as natural thickening agent

Abstract

[EN] In the process of making a print on a fabric, several steps that require many materials and substances are involved. When the purpose is to create a pattern through the use of natural products, it is necessary to pay close attention, not only to the origin and method of extraction of the pigments that you intend to use, but also, for example, to the thickeners to be added to the paste for increasing the viscosity of the pastes and molding, to the stains to be applied for better color rendering on the fabric and to the final fixatives, designed to make the product durable. Thickeners are a fundamental step in the success of printing on fabrics. These agents are generally compounds with a high molecular weight whose task is to transfer to the fabrics the dyes and chemical compounds necessary to create the printing pattern, thanks to the plastic action that they give to the compound used. As far as the environmental consequences of the use of thickeners are concerned, starting from the analysis of the wastewater of the processes, it has emerged that the use of biodegradable additives and guar rubber on the fabrics is preferable, since they are less harmful to the ecosystem. In this work different natural compounds, chitosan and alginate, are used in order to increase the viscosity of the paste prepared for printing. Color measurement of each printed cotton simple was analized and it could be appreciated that alginate paste printed on pretreated fabric with chitosan reached good results.