Detox Fashion: Sustainable Chemistry and Wet Processing Edited by Subramanian Senthilkannan Muthu

Contents

Sustainable Chemicals: A Model for Practical Substitution
Christina Jönsson, Stefan Posner and Sandra Roos

Abstract: The textile industry sees currently a fast development of legal and voluntary restrictions of chemicals content in textile products. However, the on-going phase-out work focuses on evaluating the environmental and health aspects of chemicals. The technical performance in the end application for the chemical does not receive the same attention. In addition, many research projects committed to evaluating hazardous substances and their possible alternatives also neglects the technical performance. The technical performance is left to the companies to evaluate. This may lead to inefficiency in the substitution process and also have the consequence that companies never dare to take the step to practical substitution, at least not in a proactive way. This chapter presents a model for practical substitution, developed and evaluated in several case studies, whereof two in the textile field: water and soil repellent textile coating materials and flame retarded textiles. From the general lessons learnt, an improved substitution methodology with widespread applicability has been defined.

Keywords: Chemicals _ Toxicity _ Practical substitution _ Perfluorinated substances _ Flame retardants _ Functional properties

1 Introduction
Chemicals are used among other things to provide function in materials and products. Some chemicals do show hazard characteristics that are of great concern. Thus, there is a clear need for phase out actions of such hazardous chemicals that today are used in materials and products. But, we cannot phase out chemicals without replacing their functionality.

In the manufacturing of textiles large amounts of chemicals are used. A quantitative study of the consumption of chemicals during the life cycle of textiles showed that between 1 and 5 kg of chemicals are used per kg textiles (Olsson et al. 2009). Some of the substances are harmful to health and/or the environment, with properties such as sensitizing, human toxic, eco-toxic, persistent or bio-accumulative (Munn 2011).

This chapter presents a model for practical substitution including also the technical and economical performance of alternative chemistries. The first section gives a background to why hazardous chemicals are used in textile production and occur in the ready-made textile product. Furthermore it describes the state-of-the-art regarding the legal and voluntary initiatives to phase-out hazardous chemicals in the textile industry. Finally the conditions required for a viable substitution are explained. Two specific examples are addressed where the authors have in practice applied, and iteratively developed, the suggested substitution model. The latter example involves textile chemistry and is a further development of a model used for phase out of hazardous flame retardants in plastic components in electronics as well as textiles.

1.1 Use of Chemicals in Textile Production
A wide variety of chemical substances with various functionalities, applications and properties are used in textile manufacturing. Chemical substances can be grouped in several different ways (Swedish Chemicals Agency 2004a), based on:

• chemical structure (phthalates, polychlorinated biphenyls etc.),
• functional properties (plasticizers, flame retardants etc.), or
• toxicological properties (endocrine disrupters, carcinogens, etc.).

While the chemical structure is a singular property, both the functional and toxicological properties are not; one substance may have one or many functional properties (e.g. both be a plasticizer and a flame retardant) and also one of many toxicological properties (e.g. both be endocrine disruptive and carcinogenic). Figure 1 shows the long sequence of process steps in textile production and the type of chemicals that are used in each step. In this overview, the chemicals have been described after their functional properties. The grouping of chemicals after their functional properties is a key factor in the model for practical substitution. The functional properties of chemicals can be further divided into:

• Effect chemicals, which provide function to the final textile product (softeners, plasticizers etc.). These functions are usually selected by the product designer and/or the procurer. Sometimes this group of chemicals is addressed as “functional chemicals”, hence giving function to the final product.

• Processing chemicals, which are used in the processing of textiles in the production (antifoaming agents, catalysts etc.). These functions are selected by the process engineer or sometimes specified by the chemical company to achieve compatibility with chemicals added to provide final effect.