Analysis of Disabling the Detection of Azo Dyes in Textiles in China

Analysis of Disabling the Detection of Azo Dyes in Textiles in China

1. Background Business News Agency October 25. In recent years, with the continuous improvement of global industrialization, international attention to the continuous deterioration of the quality of the global environment and the imbalance of ecological balance has been increasing. In the industries that cause environmental pollution, the textile printing and dyeing industry has been regarded as one of the highly polluting industries due to the need to use a large number of chemical synthesis products such as dyes and auxiliaries. Among dyes and dyes used in the dyeing of textile products, aromatic amines, which are intermediates of some dyes, are regarded as suspicious carcinogens by many countries. Dozens of dyes containing this substance have been listed as prohibited.

With the ban on the implementation of the azo dye regulations in the European Union, China has successively issued standards such as GB18401–2003 "National Basic Technical Specifications for Textile Products" and GB/T17592.1 ~ 17592.3-1998 "Determination of banned azo dyes for textiles". In 2006, GB/T17592-2006 “Determination of banned azo fuels for textiles” was revised and issued. These standards set forth in detail the problems and detection methods for the use of azo dyes in textile printing and dyeing processes. The ban on the detection of azo dyes has increasingly attracted the attention of people and textile manufacturers. It has become one of the most important monitoring indicators for textiles and apparel produced in China in both international and domestic trade.

The so-called azo dye is a dye whose azo group is contained in its molecular structure, in which the azo group is often connected to one or more aromatic ring systems to form a conjugate system as the color body of the dye, and is distributed in almost all colors. Therefore, not all azo dyes are banned, and only azo dyes (especially the Teng aniline series) of the 24 types of aromatic amines specified in the standards and regulations will be released after being banned. The use of these clothing or other consumer products that are banned from the production of azo dyes and their contact with human skin will mix with the components released during the normal metabolism of the human body and produce a reduction reaction to form carcinogenic aromatic amine compounds, which will become a cause of cancer in humans.

2. The status of China's banned detection of azo dyes Since the promulgation and implementation of the new standard in 2006, a large number of testing practices and surveys of inspection organizations at all levels have revealed that: in recent years, especially since 2008, China's textile and clothing products have been tested The proportion of products with banned azo dyes is very low, and the substandard report usually accounts for only about one thousandth. So what is the reason that makes China's textile and clothing products banned azo dye test results so optimistic? There are mainly three reasons:

The first is the result of stepping up publicity and strengthening supervision and inspection by quality supervision departments at all levels. Through the promotion of GB18401-2003 "National Technical Specification for Basic Safety of Textiles" by all levels of quality supervision and professional fiber inspection organizations, most textile and apparel product manufacturers deeply realize the danger of banned azo dyes and laws and regulations and trade rules in international and domestic markets. The demand for this. While enhancing the importance and cognitive ability of enterprises, we have strengthened supervision and inspection and increased efforts to investigate and punish product quality violations according to law, so that the laws, regulations, and standards stipulated in China against the use of azo dyes have been successfully implemented. Implementation.

Followed by dyeing and finishing enterprises and textile and apparel product manufacturers pay attention to the results. Judging from the situation in Zibo City, since the implementation of the new standard, the city’s large-scale textile and garment manufacturing enterprises and dyeing and finishing enterprises have all attached great importance to and responded positively. The signing of contracts or processing agreements has made the control of banned azo dyes an important item. To be specified. More than 20 printing, dyeing and dyeing enterprises visited our city and found that the dyestuffs used by the existing printing and dyeing processing companies are all environmentally friendly dyes that meet the requirements. According to the technical personnel of Zibo Daxiefang Silk Development Co., Ltd., the largest dyeing and finishing enterprise in the city, the company has adjusted the type of dyes purchased and the production process requirements in a timely manner several years ago. The azo dye component involves 88 direct dyes, 34 acid dyes, 9 disperse dyes, 7 basic dyes, 5 ice dyes, 1 oxidized chromophore, 2 mordant dyes, and 9 solvent dyes. A total of 155 dye products have been removed from the procurement catalog, so that the use of banned azo dyes will not occur at all during the production process. At the same time, the frequency of targeted inspections will be increased, thus ensuring that the processed products will not be disabled. The azo dyes meet the requirements of mandatory standards and export trade regulations.

Once again, the vast number of dye production companies actively develop and produce products that replace azo dyes. As the EU banned the introduction of azo dyeing policies, in order to meet the requirements of international trade, China's dye production companies have intensified the development of new products and developed new dye replacement products. In addition to the necessary dyeing performance and process performance, the new dye products also need to meet the environmental quality requirements. At present, the development of new environmentally-friendly dyes that have replaced azo dyes in China has reached a new level. New environmentally-friendly acid dyes, environmentally friendly direct dyes, environment-friendly disperse dyes, environmentally-friendly reactive dyes, and environment-friendly vat dyes have been successfully developed. Wait. Through the investigation of Qingdao Shuangtao Fine Chemical Co., Ltd., which specializes in the production of dyestuffs and chemical materials, it has discovered that the company has developed more than 150 new products since 2001, of which more than 40 have filled the gaps in the domestic market. The series of products fills the blank of high-grade dyes in China. The products have obtained the eco-safety certificates for dyes and additives issued by the Oeko-Tex Association. The emergence of these new products will continue to meet the domestic and international textile and apparel product printing and dyeing production processes. The ecological environmental protection requirements.

3. Problems existing in the existing detection methods The GB/T17592-2006 "Determination of banned azo dyes for textiles" standard banned azo dyes is roughly divided into two parts: pretreatment and instrument analysis. The detection process requires high precision. The process is complicated. Sample pretreatment, the sample needs to be smashed, and then after soaking in the prepared buffer solution for half an hour, the solution of the insurance powder is added to decompose the dye to produce the aromatic amine that may be present, and then the aqueous solution can be obtained by using a special extraction column. Aromatic amines were extracted into organic solvents** and subjected to a series of complicated processes such as concentration, transfer, and constant volume. Finally, samples dissolved in 1 mL of methanol and other specific solvents were obtained before they could be tested on the machine. The tester uses a GC/MS instrument, which separates various complex components in the sample and obtains detailed data of each component through scanning. The operator analyzes the data to complete the inspection of the sample. It can be seen from the above that the whole process is numerous and complex, and it tends to produce high uncertainty. Minor omissions will lead to erroneous inspection results, which will have a serious impact on testing organizations and customers.

As the main instrument used in the testing method, the GC/MS instrument is basically all imported, and the price is very expensive. Generally, the equivalent of *** is about 800,000 yuan per sample. At the same time, a lot of high purity is used in the inspection process. Materials such as reagents and imported extraction columns are also quite expensive. At present, most city-level testing agencies do not have the ability to purchase and equip this testing equipment and carry out corresponding inspections, which restricts the coverage of banned azo dyes inspection in China. At the same time, due to the relatively high cost of testing, the burden on companies for disabling the detection of azo dyes is also relatively heavy, and the enthusiasm of enterprises for inspection has also been affected to a certain extent.

4. Suggestions on the detection work For the current banned azo dye detection methods, due to the high cost of instrumentation equipment, cumbersome methods, high detection cost, small test coverage, and low actual detection frequency of the company, problems should be caused. Party's attention. This article summarizes the following two suggestions for reference.

The first is to increase the research and development of domestic testing equipment, break the monopoly of developed countries on high-precision detection equipment, and produce domestic testing equipment with relatively low prices and corresponding functions to meet the needs of the domestic testing market;

The second is to revise the detection method of banned azo dyes at the appropriate time. In view of the fact that the unqualified batches found during the actual inspection work are very low, it is recommended to determine the existence of banned azo dyes in the tested samples by using a pre-determined detection method. , And then use quantitative methods to determine the number of its varieties and content, using this method instead of the current direct quantification method to improve the detection efficiency, reduce the detection cost and detection risk.

(Li Junye China Fiber Inspection)

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