Possibility analysis of dioxin production or pollution in the production and use of polystyrene foamed tableware
1. Composition of raw materials
The main raw materials of polystyrene foamed tableware are polystyrene, talcum powder, calcium stearate, butane and so on.
Polystyrene: Its production process is that monomer styrene is polymerized in a sealed reaction kettle under the action of catalyst at high temperature and high pressure. Although styrene is an aromatic compound, its reaction is carried out under sealed oxygen-free conditions, and there is no condition to produce dioxins, which meets the food hygiene and requirements.
Talcum powder: it is an inorganic mineral (magnesium silicate containing crystal water), and its dosage is about 1%, which acts as a nucleating agent and is of medical grade.
Calcium stearate: saturated fatty acid salt, the dosage is about 1%, which acts as a lubricant and is medical grade.
Butane: saturated hydrocarbon, foaming agent. In the past, some production lines used freon as foaming agent. In order to protect the atmospheric ozone layer, with the assistance of the United Nations Multilateral Fund, butane foaming agent has been completely used.
2. Process flow
The production process of polystyrene foamed tableware is a physical mixing process. Talcum powder is mainly used to absorb heat without chemical reaction: butane foaming agent is coated in molten polystyrene resin and expands into bubbles.
3. The process of transportation, storage and use of polystyrene foamed tableware
Styrofoam tableware is a container that comes into direct contact with food. Its hygiene conforms to the national standard GB131191,and there are strict requirements for its packaging, storage and transportation. After the tableware is formed, it will be packed in PE plastic film bags and then packed in cartons, which will not be in contact with the external environment, even if there is a trace of chlorine-containing gas in the air, it will not be polluted. The use process is to open the bag when using, and the temperature should not exceed 100℃ when filling hot rice.
According to Professor Chen and many materials, the possible sources of dioxins are: (1) formed as trace impurities in chlorinated aromatic products, such as PCBs and sodium chlorite; (2) It is generated during thermal reaction. When the banned substances contain petroleum products such as cellulose and coal, they contain inorganic chlorine at 300℃, which is easy to generate dioxins. Styrofoam tableware does not contain chlorine, nor does it have a high temperature of several hundred degrees, and it does not have the conditions for dioxin production.
According to the analysis of the above links, it can be concluded that polystyrene foamed tableware will not be polluted by substances that produce dioxins during production and use.
4. The problem that polystyrene foamed tableware contains toxic substances.
On this issue, four people, including Nozichikawa Village of Japan National Institute of Medical Devices and Food Hygiene, published a paper entitled "Styrene oligomer in food polystyrene products" at the Japan Health Association held on May 1998, saying that 25 kinds of polystyrene food packaging containers were widely collected in this study, including disposable water cups, vegetable trays, instant noodle bowls, soup bowls and so on. Taking the substances contained in food as solvent, the simulated dissolution test shows that these products contain dissolved oligomers: the average extraction amount of styrene dimer is 380μg/g, and the dimer is 9 1 20μ g/g. Mr. Kawamura did not mention the toxic amount of dimer and dimer in this article, but in1April, 1998. Although we don't know how seriously these substances damage hormone secretion, we must pay attention to the content of harmful substances in packaging containers that are in direct contact with imported food. " This shows that although harmful substances such as styrene dimer and trimer have been detected from Mr. Kawamura's experiment, their toxic content is still a problem to be determined.
However, after Tokyo News published a paper, 1998 once aroused the fear of polystyrene foamed tableware in Japan and South Korea. It is reported that the sales of instant noodles in Korea/KOOC-0/998 decreased by 30-40% in the second quarter, and that in Japan/KOOC-0/99 decreased by/KOOC-0/5% in the first quarter. After that, due to the foaming of polystyrene and the intensified publicity, explanation and continuous announcement of tableware manufacturers, the public's fear gradually disappeared. South Korea 1998' s sales of instant noodles rebounded by 20~30% in the third quarter, and now it has resumed normal production and sales. In addition, European organizations tested 23 brands of polystyrene containers, and the United States also studied and tested 7 samples, and found no problems.
My personal view on this issue is that, with the development of science and technology, it is right to trace some harmful substances that may lead to poisoning based on the responsibility for people's health. As we all know, many chemicals contain a certain amount, which will dissolve some harmful substances under certain conditions, which is not surprising. The question is how much of these substances constitute toxicity, or how much they accumulate will endanger human health. There should be a quantity standard, but there is no certain content standard. It is unscientific to judge all substances as containing some harmful components or substances that may affect people's health after excessive use. If so, we are exposed to too many toxic substances in our daily life. Long-term heavy drinking may cause fatty liver, liver cirrhosis, liver cancer and other physical diseases, and binge drinking may lead to alcoholism. As the saying goes, it is a three-point poison. Normal use can cure diseases, and excessive use can lead to poisoning and even death; So are alcohol and drugs also toxic substances? The knife cuts bread and fingers. Eating too much food can even kill people. So whether any substance contains poison or not should have a standard concept.
At present, the polystyrene detected in Japan will dissolve dimer and trimer under certain conditions, but how much toxicity it will have has not been determined, and the United Nations Health Organization has not stipulated it. Follow-up study is appropriate, but it is unreasonable to make an issue of it or even attack it. In addition, measures have been taken at home and abroad to avoid direct contact with food through coating.
Therefore, I hope that when you observe, analyze and report anything, you must adopt a scientific and realistic attitude, and don't follow others' advice, so as to promote the smooth and healthy development of China's fast food packaging and container industry.