Analysis Of Banned Azo Dyes In Textiles In China

1 background

In recent years, with the global

With the promulgation and implementation of the EU banned azo dye regulations, China has issued GB18401 - 2003 "basic safety technical specifications for National Textiles" and "GB/T17592.1~17592.3 - 1998" testing methods for prohibited azo dyes in textiles. In 2006, it reissued the GB/T17592 - 2006 "determination of prohibited azo fuel in textiles". These standards have made detailed provisions on the use of azo dyes in textile products processing and testing methods.

The detection of banned azo dyes has attracted more and more attention from the people and the textile manufacturers. It has become one of the most important monitoring indicators for the production of textile and apparel in international and domestic trade.

Azo dye is the dye containing azo group in its molecular structure. Azo is often linked by one or more aromatic ring systems to form a conjugated system as the chromogenic body of dyes, almost all of the colors.

Therefore, not all azo dyes are forbidden. The banned products will only release the 24 class aromatic amine azo dyes (especially aniline Series) specified in the standard and regulations.

The use of these banned azo dyes to produce clothing or other consumer products after contact with human skin will mix with the components released in the normal metabolic process of human body and produce a reduction reaction to form carcinogenic aromatic amine compounds, and become the inducement of human cancer.

2 status of banned azo dyes in China

Since the promulgation and implementation of the new standard in 2006, after a great deal of testing practice and investigation by various testing organizations, it has been found that in recent years, especially since 2008, the ratio of products with banned azo dyes in textile and clothing products in China has been very low, and generally the report is only about 1/1000.

What is the reason why the test results of banned azo dyes in China's textile and clothing products are so optimistic? There are three main reasons:

First of all, the quality supervision departments at all levels have stepped up publicity and strengthened supervision and inspection results.

Through various levels of quality supervision and professional fiber inspection agencies to publicize the GB18401 - 2003 "national textile basic safety technical specification", the vast majority of textile and garment production enterprises have deeply recognized the harm of azo dyes and the requirements of laws and regulations and trade rules in the international and domestic markets.

While enhancing the importance and cognitive ability of enterprises, we should strengthen supervision and inspection and intensify efforts to investigate and punish product quality violations according to law, thus enabling our country to implement laws, regulations and standards for the use of banned azo dyes smoothly.

Followed by the dyeing and finishing enterprises and textile and garment production enterprises attach great importance to the results.

Judging from the situation in Zibo, since the implementation of the new standard, the textile and garment production enterprises and dyeing and finishing enterprises in our city have attached great importance to and actively responded to it, and have banned the control of azo dyes as important clauses in signing contracts or processing agreements.

More than 20 printing and dyeing and dyeing enterprises in our city have found that the dyestuffs used by the existing printing and dyeing enterprises are all environmentally friendly dyes.

Technicians introduced the implementation of the banned azo dye standard. Many years ago, the company adjusted the varieties and production process requirements of the purchased dyes in a timely manner. There were 88 direct dyes, 34 acid dyes, 9 basic dyes, 5 ice dyes, 1 dyestuffs, 2 mordant dyes and 9 dye dyes of the banned azo dye components from the purchase catalogue, so that no banned azo dyes were used in the production process. At the same time, the frequency of targeted detection was also increased, thus ensuring that the processed products do not contain prohibited azo dyes, so that they meet the requirements of mandatory standards and export trade. According to the largest dyeing and finishing enterprise in our city, Zibo dya Fang Silk Development Co., Ltd.

The third is the result that the majority of dyestuff manufacturers actively develop and produce products instead of banned azo dyes.

With the introduction of the EU banned azo dye policy, in order to meet the requirements of international trade, China's dyestuff manufacturers have intensified the development of new products and developed new dyestuffs instead of products.

Besides the necessary dyeing properties and technological properties, the new dyestuff products also need to meet the requirements of environmental protection quality.

At present, the development of new environmentally friendly dyes to replace azo dyes in China has reached a new level. New environmentally friendly acid dyes, environment-friendly direct dyes, environment-friendly disperse dyes, environment-friendly reactive dyes and environment-friendly vat dyes have been successfully developed.

Through the investigation of Qingdao double peach Fine Chemical Co., Ltd., which specializes in dyeing and finishing products, we found that since 2001, more than 150 new products have been developed, more than 40 of which have filled the domestic blank. The new generation of olive and olive products have filled up the whiteness of high-grade dyes in China. The products have won the certificate of ecological safety of dyes and auxiliaries issued by the Oeko-Tex Association. The emergence of these new products will continuously satisfy the ecology of the printing and dyeing process of textile and garment products at home and abroad.

3 existing problems in testing methods

The testing of banned azo dyes can be divided into two parts: pretreatment and instrumental analysis with the standard of GB/T17592 - 2006 "determination of prohibited azo dyes in textiles". The detection process requires high accuracy and complex process.

When samples are pretreated, the samples should be cut and broken, then soaked in half hour in a well prepared buffer solution, and then added into the powder solution to decompose the dye to produce aromatic amine. Then the aromatic amine in the aqueous solution can be extracted into the organic solvent ether by using a special extraction column. After a series of complex processes such as concentration, pfer and volume tolerance, the sample dissolved in 1 mL methanol and other specific solvents can be finally detected.

The GC-MS is used to separate all the complex components in the sample, and the detailed data of each component are obtained by scanning. The operator completes the inspection of the samples by analyzing these data.

It can be seen from the above that the whole process is more complex and prone to higher uncertainty. Minor omissions will lead to erroneous inspection results, which will have a serious impact on testing organizations and clients.

As the main instrument used in the testing method, the GC-MS is basically imported at present. The price is very expensive. In general, each unit is equivalent to RMB 800 thousand yuan. At the same time, a lot of high purity reagents and import extraction columns are used in the process of testing and processing, and the cost is quite high.

At present, most municipal testing institutions are unable to purchase the equipment and carry out corresponding inspection work, which restricts the coverage of banned azo dye project detection in China.

At the same time, because the cost of detection is relatively high, it also causes enterprises to bear the burden of banned azo dyes detection, and the enthusiasm of enterprises for inspection has also been affected to a certain extent.

4 suggestions for testing work

For the existing banned azo dye detection methods, due to the high cost of instrumentation, the tedious method, the high cost of detection, the small coverage of detection and the low frequency of testing, the attention of all parties concerned should be paid attention to.

This paper summarizes the following two suggestions for reference.

First, we should increase the research and development efforts of domestic testing equipment, break the monopoly situation of developed countries on high-precision detection equipment, and produce homemade testing equipment with relatively low price and relatively low function, so as to meet the needs of domestic testing market.

Two, it is timely to amend the detection methods of banned azo dyes. In view of the fact that the unqualified batches found in the actual testing work are very low, it is suggested to use qualitative test to determine whether there are prohibited azo dyes in the tested samples, and to confirm the existence of the samples and determine the number of varieties and contents by quantitative method.