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Test for the harmful azo colorants in textiles Bookmark and Share

Posted by Sazid Rahman

Azo colorants are the most important class of synthetic dyes and pigments, representing 60 - 80% of all organic colorants. They are used widely in substrates such as textile fibres, leather, plastics, papers, hair, mineral oils, waxes, foodstuffs and cosmetics.

Hence azo colorants are part of our everyday colorful life, they are all around us and we could not do without them.

It allows colors with outstanding colorfastness and wide huge spectrum of colors.

Some of these dyes have the capacity to release certain aromatic amines which pose cancer risks. For this reason, the European Union has laid down legislation to prevent exposure to these hazardous amines. This implies that azo dyes containing aromatic amines can no longer be used to dye textile and leather products that may come into contact with the skin.

Please note that all the different parts of the finished product should be tested, and if there are several colors involved, it is not necessary to test them all separately. Only if the general test proves that there are banned azo dyes in the product, more tests will be needed.

Restrictions

EU legislation specifically prohibits the use of the 22 aromatic amines included in the next table in a concentration above the threshold limit of 30 ppm(mg/kg) (detection limit). Please note that all parts of a product should comply with this limit, and that this limit applies to each amine separately. E.g. a textile shoelace of leather footwear needs to comply with the limit of 30 ppm, as well as the leather parts of footwear. It is not allowed to take the average concentration of a certain amine in the complete product.

Table: List of aromatic amines according to the EU Directive 2002/61/EC

Sl. No.

Substance Name

CAS Number

01

Biphenyl-4-ylamin 4-aminobifenyl Xenylamine

92-67-1

02

Benzidine

92-87-5

03

4-chloro-o-toluidine

95-69-2

04

2-naphthylamine

91-59-8

05

o-aminoazotoluene

4-amino-2’,3-dimethylazobenzene

4-o-tolylazo-o-toluidine

97-56-3

06

5-nitro-o-toluidine

99-55-8

07

4-chloroaniline

106-47-8

08

4-methoxy-m-phenylenediamine

615-05-4

09

4,4'-methylenedianiline

4,4'-diaminodiphenylmethane

101-77-9

10

3,3'-dichlorobenzidine

3,3'-dichlorobiphenyl-4,4'-ylenediamine

91-94-1

11

3,3'-dimethoxybenzidine

o-dianisidine

119-90-4

12

3,3'-dimethylbenzidine

4,4'-bi-o-toluidine

119-93-7

13

4,4'-methylenedi-o-toluidine

838-88-0

14

6-methoxy-m-toluidine

p-cresidine

120-71-8

15

4,4'-methylene-bis- (2-chloro-aniline)

2,2'-dichloro-4,4'-methylenedianiline

101-14-4

16

4,4'-oxydianiline

101-80-4

17

4,4'-thiodianiline

139-65-1

18

o-toluidine

2-aminotoluene

95-53-4

19

4-methyl-m-phenylenediamine

95-80-7

20

2,4,5-trimethylaniline

137-17-7

21

o-anisidine

2-methoxyaniline

90-04-0

22

4-amino azobenzene

60-09-3


Articles covered in the EU Directive

Textile and leather products that may come into direct and prolonged contact with the human skin or oral cavity. The examples of products listed are:

• clothing, bedding, towels, hairpieces, wigs, hats, nappies and other sanitary items, sleeping bags;

• footwear, gloves, wristwatch straps, handbags, purses/wallets, briefcases, chair covers, purses worn around the neck;

• textile or leather toys and toys which include textile or leather garments;

• yarn and fabrics intended for use by the final consumer.

Test Methods:

 General Textiles: EN14362-1:2003

 Polyester: EN14362-2:2003

 Leather: CEN ISO/TS 17234:2003

 Determination of P-aminoazobenzene (4-AAB)

Chemistry of aromatic amine release

Azo dyes contain one or more nitrogen-nitrogen double bonds called azo groups in their chemical structure, see Fig. 1.

-N=N -

Fig.1: Azo group

Under reductive conditions using sodium dithionite these azo groups can be cleaved to form 2 amines, which can be schematically shown as in Fig. 2.



Fig.2: Reductive cleavage of the azo dye to form amines

A small number of the aromatic amines are classified as being carcinogenic or potentially carcinogenic to humans. Only those few azo dyes that can release these amines upon reductive cleavage are affected. It has been estimated that less than 4% of known azo dyes structures may release the corresponding amines.

False positive results
For certain dyed goods a listed amine is detected under the conditions of the analytical test even though no banned azo dye is present in the consumer good. The amine is an artifact of the test procedure, resulting from a chemical reaction other than azo cleavage. So, care should be taken that detected aromatic amines originate from azo colorants and not from other materials such as Polyurethane.

Click here to download a test report sample from ITS.

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Common Seam Quality Defects in Denim Bookmark and Share

Posted by Sazid Rahman

A visual catalog of seam defects occurred during jeans manufacturing. Includes a detailed illustrated description of the defects and recommended solutions to them.

Click here to download

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Micromerchandising: The Next Generation Bookmark and Share

Posted by Sazid Rahman

A report, explaining the concept of micromerchandising and it's scope and area of application by Stacy Baker and published by Aroq Limited in April 2007.

Click here to download

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A report on apparel manufacturing technology Bookmark and Share

Posted by Sazid Rahman

A just-style report on apparel manufacturing technology by Malcolm Newbery and published on September 2005 by Aroq Limited.

Click here to download

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The Effects of Different Fabric Types and Seam Designs on the Seam Efficiency Bookmark and Share

Posted by Sazid Rahman

An undergraduate thesis paper by Courtney LaPere of Eastern Michigan University.

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Stitch and Seam Guide to the ASTM Standard D-6193 Bookmark and Share

Posted by Sazid Rahman

A very good guide to learn about different seam types and stitch classes. This guide is designed to enable you to easily find and utilize the correct ASTM D-6193 stitch and seam standard for your product specifications, communications and development.

here's the link

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The Sewability of Elastic Fabric Bookmark and Share

Posted by Sazid Rahman

A complete guideline for sewing elastic fabric. Mentions what type of stitch should be used, what type of stitch density should be used, what type of needle should be used to sew elastic fabrics etc.

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Sewing Knitted Fabrics Bookmark and Share

Posted by Sazid Rahman

A guideline for sewing of outerwear, underwear, lingerie, shirts, blouses, swimwear and leisurewear. Also lists the most important stitch types in the knitted fabrics industry with sewing thread requirements for standard sewing parameters.

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Determining your sewing thread requirement Bookmark and Share

Posted by Sazid Rahman

A document developed by Amann Group, Germany for their software. Lists different stitch class with appearance and their consumption. Also gives you idea about the factors that influence thread demand.

Click here to download

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A-Z about Sewing Thread Bookmark and Share

Posted by Sazid Rahman

A document containing everything you need to know about sewing thread like their types, how they are made, sizing systems, suitable needle and machine, their fastness and a glossary.

Thanks to Mr. Priyank Goyal for providing this document.

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Introduction to Apparel, Merchandising, Design and Textiles Bookmark and Share

Posted by Sazid Rahman

Lecture Notes by Dr. Joan Anderson of a course titled 'Introduction to Apparel, Merchandising, Design and Textiles' of Washington State University. The Business of Fashion: Designing, Manufacturing, and Marketing by Burns & Bryant and published by Fairchild is used as reference book.

Chapter One: From Spinning Machine to Quick Response

Chapter Two: Business and Legal Framework of Textile and Apparel Companies

Chapter Three: The Structure of the U.S. Textile Industry

Chapter Four: Ready-to-Wear Company Organization

Chapter Five: The Creation Stage: Research

Chapter Six: The Creation Stage: Design

Chapter Seven: Design Development and Style Selection

Chapter Eight: Marketing an Apparel Line

Chapter Nine: Preproduction Processes

Chapter Ten: Sourcing Decisions and Production Centers

Chapter Eleven: Production Processes and Quality Assurance

Chapter Twelve: Distribution and Retailing

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Lecture Notes on various topics related to textile, apparel and fashion Bookmark and Share

Posted by Sazid Rahman

A great collection of lecture notes on textile and apparel manufacturing and merchandising as well as fashion designing from Rai Foundation Colleges under their OpenCourseware initiative.

Lecture Notes available for these courses:

* Clothing Manufacture & Production Operation
* Textile Manufacturing Techniques
* Visual Merchandising
* Fashion Forecasting
* Experimental Embroidery Textiles
* Accessory Designing
* Fashion Stylization
* Model Drawing
* Design Exploration in Fashion
* Techniques & Processes in Fashion
* Brand Positioning
* CAD-CAM-II

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European (International) Care Labeling Bookmark and Share

Posted by Sazid Rahman

A document on the status of the European (International) Care Labeling published by the GINETEX technical commission.

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Regulation on Apparel Labeling and Apparel Safety Bookmark and Share

Posted by Sazid Rahman

A document on US Government's Regulation on Apparel Labeling and Apparel Safety.

Click here to download

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Guide to Apparel and Textile Care Symbols Bookmark and Share

Posted by Sazid Rahman

A document published by the Canada’s Office of Consumer Affairs (OCA).

Click here to download

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Clothing Appearance & Fit: Science and technology Bookmark and Share

Posted by Sazid Rahman

A book written by J. Fan, W. Yu and L. Hunter and published by Woodhead Publishing Limited in association with The Textile Institute

ISBN 1 85573 745 0

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