Plastic products industry should strictly prohibit the "chrome" content exceeding the standard

Unwelcome "chrome"

Chromium is a metallic element that is versatile. Some plastic products , such as ABS plastic products, after degreasing, can be etched with a relatively thin chromic acid treatment solution to treat the surface layer. Its typical treatment formula is 420g/L chromic acid and 200ml/L sulfuric acid (specific gravity 1.83). Etching with chromic acid treatment solution has the great advantage that even if the shape of the plastic product is complicated, it can be uniformly treated. But even if chromic acid treatment or chrome plating has considerable advantages, these two types of treatment processes are not popular in the surface treatment of plastic products. On the one hand, there are certain dangers in operation, and there are also pollution problems. What is more important is that the chromium residue in the finished product will threaten the health of human beings.

As early as ten years ago, hexavalent chromium plating has been banned in China's electronic information industry; in the EU, hexavalent chromium, which is carcinogenic or mutated, is not allowed to be sold. With the introduction of relevant laws, it may not be nonsense to talk about "chrome" discoloration.

No stranger to "chrome"

We have to deal with chrome every day in our lives. Chromium has been used very early in our history, and the addition of chromium increases the corrosion resistance of metals. In addition, chromium can increase the luster of metal surfaces, such as the surface of bicycles and automotive flash metal may be plated with chromium. The metal chromium that we are exposed to in our daily lives is insoluble in water, so we don't have to worry about chromium entering our bodies when using metal products containing chromium such as stainless steel.

This blue-white multivalent metal element is widely present in the natural environment, and the chromium in the earth's crust is mainly present in the form of trivalent chromium and hexavalent chromium. The chromium content in the atmosphere and water is extremely low, while the chromium in the soil is large. However, due to its low solubility and stable nature, it is often difficult to enter plants, so the chromium content in food is generally low.

Chromium is not all toxic. It is even a trace element essential to the human body. Its toxicity is related to its valence state. It is classified into trivalent chromium and hexavalent chromium according to its valence. Trivalent chromium is an important element for the human body. Appropriate intake is beneficial to the human body. It can affect lipid metabolism and promote protein metabolism and growth. However, if we ingest a large amount of trivalent chromium for a long time, then on the one hand, it is an antioxidant system that affects our body, and it is easy to get some chronic oxidative diseases, such as diseases such as diabetes and high blood pressure. On the other hand, since the antioxidant system is damaged, it is prone to such abnormal growth of tumors and the like.

Unfriendly hexavalent "chrome"

Compared with trivalent chromium, hexavalent chromium is more toxic, about 100 times that of trivalent chromium. Clinically, the damage of hexavalent chromium and its compounds to the human body is usually manifested in three aspects. One is damage to the skin, leading to dermatitis, pharyngitis, etc.; the second is damage to the respiratory system, causing pneumonia, bronchitis and other diseases, the third is damage to the digestive system, ingestion and even long-term exposure to chromate, easily lead to gastritis, gastric ulcer and intestinal tract ulcer. Excessive intake of hexavalent chromium can also cause kidney failure and even cancer.

Hexavalent chromium is a strong oxidant, has a strong biological toxicity, is easily absorbed by the body, and invades the body through the digestive tract, respiratory tract, skin and mucous membranes. Internationally, hexavalent chromium is listed as one of the eight most harmful chemicals in the human body and is recognized as a carcinogen. In China, chromium-containing wastes are listed in the National Hazardous Waste List.

Currently, the hexavalent chromium content of drinking water in the United States is no more than 100 micrograms per liter of water. The standard in China is no more than 50 micrograms per liter of drinking water, and farmland irrigation water does not exceed 100 micrograms per liter of water. The pollution of hexavalent chromium comes mainly from two aspects. One is the mining of chrome ore. If the sewage treatment in the industrial production process is improperly treated, it is likely to cause hexavalent chromium to contaminate the soil and water source; the other is leather processing. Unscrupulous companies use industrial chromium salts to neutralize and decolorize and clean leather waste, and then make industrial gelatin.

The reason for the "glue" discoloration is that the hexavalent chromium content of industrial gelatin used in poison capsules often exceeds several times or even dozens of times the chromium content of gelatin in regular manufacturers. So in any case, this industrial gelatin should not appear in foods and medicines.