Chemicals used in textile processing

Here’s to new beginnings and fresh starts! I hope you are all looking forward to a fulfilling 2013.

Zydex Industries

Everybody seems to be up in arms about chemicals used in fabrics, some of which have gotten lots of media attention recently, such as PBDE’s, which were featured in the Chicago Tribune series “Playing with Fire” and NPE’s, featured in Greenpeace’s “Toxic Threads” campaign. But why are these chemicals in our fabrics – how are they used, and why? What do they do to us – if anything?

We thought it would be a good idea to take a look, individually, at some of the chemicals used in textile processing and try to answer those questions: what the chemicals are designed to do, what they can do to us – and whether we can avoid using them.

One thing I know for sure – the textile industry uses lots of chemicals. During manufacturing, it takes from 10% to 100% of the weight of the fabric in chemicals to produce that fabric.(1) And the final fabric, if made of 100% natural fibers (such as cotton or linen), contains about 27% , by weight, chemicals.(2) And many of those chemicals are simply not benign.

Why does the industry use so many chemicals? What are they used for?

Most fabrics are finished in what is called “wet processing” where the process is accomplished by applying a liquid – which accomplishes some sort of chemical action to the textile – as opposed to “dry processing”, which is a mechanical/physical treatment, such as brushing. It is a series of innumerable steps leading to the finished textile, each one of which also has a complex number of variables, in which a special chemical product is applied, impregnated or soaked with the textile fiber of the fabric. A defined sequence of treatments can then be followed by another sequence of treatments using another chemical substance. Typically, treatments are arranged to permit a continuous mode of sequences.

The chemicals used can be subdivided into:
• Textile auxiliaries – this covers a wide range of functions, from cleaning natural fibers and smoothing agents to improving easy care properties. Included are such things as:
o Complexing agents, which form stable water-soluble complexes
o Surfactants, which lowers the surface tension of water so grease and oil to be removed more easily
o Wetting agents, which accelerates the penetration of finishing liquors
o Sequestering agents
o Dispersing agents
o Emulsifiers
• Textile chemicals (basic chemicals such as acids, bases and salts)
• Colorants, such as:
o Dyes
o Dye-protective agents
o Fixing agents
o Leveling agents
o pH regulators
o Carriers
o UV absorbers
• Finishes
The 2010 AATCC (American Association of Textile Chemists and Colorists) Buyer’s Guide lists about 2,000 chemical specialties in over 100 categories offered for sale by about 66 companies, not including dyes. The types of products offered run the gamut from antimicrobial agents and binders to UV stabilizers and wetting agents.

The chemicals used get very specific: for example, Lankem Ltd. is one such manufacturer of a range of textile chemicals. According to their website, their Kemtex AP, for example, is an “anti-precipitant” to be used “where dyes of opposing ionicity may be present in the same bath” and their Kemtex TAL is a levelling agent for wool which is a “highly effective level dyeing assistant for acid, acid milling and prematallised dyes on wool.”

In addition to the branded products supplied by chemical companies, which are made of unknown components because they’re proprietary, we know many chemicals are necessary to achieve certain effects, such as PBDEs for fire retardants, formaldehyde resins for crease resistance or PFOA’s for stain protection. (Per- and polyfluoroalkyl substances are both included as PFAS.)

The chemicals used in these branded products to create the effects above include chemicals which have been proven to be toxic, or to cause cancers or genetic mutations in mammals (i.e., us too). The following is by no means an all-inclusive list of these chemicals:
• Alkylphenolethoxylates (APEOs)
• Pentachlorophenols (PCP)
• Toluene and other aromatic amines
• Dichloromethane (DCM)
• Formaldehyde
• Phthalates
• Polybrominated diphenyl ethers ( PBDE’s)
• Perfluorooctane sulfonates (PFOS)
• Heavy metals – copper, cadmium, lead, antimony, mercury among others
So starting next week, we’ll begin by looking at the some of the chemicals used in textile processing, to give you an idea of why we’re making all the fuss about organic fabrics.

(1) Environmental Hazards of the Textile Industry, Hazardous Substances Research Centers, South and Southwest Outreach Program, US EPA funded consortium, June 2006.
(2) Lacasse and Baumann, Textile Chemicals: Environmental Data and Facts; German Environmental Protection Agency, Springer, New York, 2004, page 609.