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Trend Analysis And Countermeasures Of EU Six Price Chromium Control

2014/6/11 16:11:00 54

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1. The main types of recalled products are .
 in the first quarter of 2014, the Rapex system recalled 13 Chinese made "a" target= "_blank" href= "http://www.91se91.com/" > leather "/a" products. On average, 1 leather products were recalled every week due to the detection of six valent chromium. 
 the recalled products are: leather gloves, ladies leather "a target=" _blank "href=" http://www.91se91.com/ "> shoes < /a > baby shoes and safety shoes. Recall is shown in Figure 1. 
 on the recall of the first quarter of 2014, ladies' shoes are the products with high recall frequency, but the conclusion is unscientific based on the data of the first quarter. Recalling the data of Rapex in 2013, the high frequency products of six chromium exceeding the standard were also for ladies' shoes. Besides, the recalled products also included bracelet, cortical bikini, children's shoes, safety shoes and so on. 
 two, analysis of problem product processing measures 
 processing measures for products recalled in the first quarter: 
 ladies' shoes: 6 products, 5 German recall all made voluntary withdrawal, 1 other women's shoes recalled by Spain were forced to withdraw from the shelves; 
 leather gloves: 3 leather gloves are recalled by Germany and are voluntarily removed. 
 safety shoes: 1 safety shoes recalled by France are treated as refuse to import (the recall is based on safety shoes standard: EN ISO 20345:2011); 
 baby shoes: all 3 baby shoes are recalled by France, and the measures taken must be stricter than those of the above products, forced to be removed and destroyed. 
 according to the data of the six valent chromium concentration in the recalled products, there is little correlation between the treatment measures and the six valent chromium concentration detected, but it is related to the product type and the recall state. 
 according to the above data, the detection of HCCO indicates that children's products with < a > Leather > /a > products need more attention, and their enforcement is obviously greater than other products. In addition, countries that have recalled related products in particular need to attract the attention of exporters, while other countries should not ignore them. 
The hazards and causes of three and six chromium valence 
 six valence chromium is an invasive poison. It stimulates the skin and mucous membrane. It can cause dermatitis, eczema, tracheitis and rhinitis, and can invade the human body through digestive tract, respiratory tract, skin and mucous membrane. It has carcinogenic effect. 
It is a puzzling and objective problem to detect six valence chromium in finished leather. Because the chrome tanning agent used in tanning leather is trivalent, not six valent, even if six chromium is not detected in the chromium powder, six valent chromium can be detected in the leather produced. 
 at present, it is generally believed that the production of six valent chromium in leather may be the use of chromium powder, chrome tanning agent and chromium containing additives which contain six valence chromium or over six chromium in the leather production process, such as chromium salt dye, pigment paste, < a > fixing agent < /a > medium water, etc. 
 in addition, the influence of production process on the formation of six valence chromium is also more complicated, generally summarized as follows: 
 1. the high pH value of the bath liquid during wet dyeing and finishing process: when the pH of the process is more than 5, the trivalent chromium will be oxidized to six valent chromium during the neutralization, retanning and dyeing and fatliquoring of chrome tanned leather. 
 2. fatliquoring agent: fatliquoring agent itself does not contain chromium, but fatliquoring agent usually contains unsaturated bond, which can oxidize trivalent chromium in peroxide environment. The higher the iodine value is, the easier it is to promote the formation of six valent chromium. 
 3. heating and illumination: this reason is basically the root cause of the formation of six valent chromium. The higher the temperature, the stronger the light, and the longer the action time, the higher the six valence chromium content in the leather. 
 4. the relative humidity in the air: the humidity of the finished leather during storage is one of the main influencing factors. The experiment proved that the high humidity of the air is beneficial to inhibit the six valent chromium in the leather. 
 in short, the reason for the formation of six valent chromium in leather is very complicated. So far, the business community has not yet reached a conclusion, and can only take different measures to deal with the problem according to the actual production situation. 
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 leather manufacturers in some European countries do better in chrome treatment, that is, the use of chrome tanning agents can also control almost no six valent chromium in the process. This technical problem is widespread in China. In the process of traditional leather tanning process control, the details of the implementation of the process parameters are overlooked, such as excessive liquid volume, low pH value of alkali extraction terminal, insufficient production time, no rinsing of blue drum, no aging, subsequent use of chromium removal agents, and high thermal energy generated by mechanical action. 
 four, the six valent chromium solution in leather is less than /strong > /p >
 there are many reasons for the formation of six valent chromium in leather. Single method can not completely prevent the formation of six valent chromium. To meet the stringent requirements of the EU standard, we need to control and control the whole leather making and transportation process. In view of the above causes, the solutions can be roughly summarized as follows: 
 1. first of all, six valence chromium should be investigated for raw materials, especially coloring agents, chrome tanning agents and chromium salts additives. 
 2. in the leather making process, we must ensure that the whole process parameters can be kept under a condition of six valent chromium inhibition, for example, the pH value is guaranteed to be around 5 and avoid the dramatic change of pH value. 
 3. choose better processing aids: use reductive retanning agent, usually plant retanning agents have good reducibility; avoid using fatliquoring agent with higher unsaturated value. 
 4. using effective reductant: in Duan Limin and other studies, Sodium Bisulfite and THPS (four hydroxymethyl phosphonic acid) have better effect on eliminating six valent chromium, and THPS treated leather has brighter colors. 
 5. leather storage conditions: to ensure that the moisture content of leather is not exceeded or not affect its quality, the humidity in the environment is controlled at a higher level, and as far as possible avoid storing at high illumination and high temperature for a long time. 
 hicker detection suggests that the revision of the REACH Regulations means that the six price chromium control in leather will be upgraded comprehensively, especially after the end of the transition period. The law enforcement efforts will also be improved correspondingly. The relevant European leather enterprises should pay close attention to the rectification of the internal production lines and the training of personnel in the legislation. 
 in addition, the comprehensive upgrading of six valent chromium control is an opportunity for already mature and mature leather enterprises. They can take the lead in seizing the EU market more effectively, while the tanning technology is backward. Enterprises with unstable control of six valent chromium will have to rectify their backward production lines, which will also make some tanning enterprises face severe problems of survival.