Analysis of the most popular polystyrene foam tabl

2022-08-15
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An analysis of the concept of circular economy of polystyrene foam tableware (V)

3.2.2 about styrene monomer

about the problem that PS contains residual monomers or will release monomer poisoning when used above 65 ℃, it has been one of the main problems accusing PSP tableware of being toxic for many years

3.2.2.1 as for the problem of containing residual monomers, according to the data provided by the manufacturer, the PS produced in China strictly implements the national standard that the content of styrene monomers shall not exceed 1000ppm, the approval standard of the United States Food and Drug Administration (FDA) is 5000ppm, and the Japanese food hygiene law stipulates that PS used for plastic products and containers used for food packaging, The total concentration of volatile substances (styrene, toluene, ethylbenzene, cumene, n-butyl benzene, etc.) must be less than 5000ppm, but as a foaming container for hot soup, the total concentration must be less than 2000ppm, in which the concentration of styrene, diene dimer and ethylbenzene shall not exceed 1000ppm respectively. The total concentration of PS for other food containers must be less than 10000 ppm

citizens can arrange time in advance to avoid congestion. 3.2.2.2 about the problem that PSP tableware will release monomers when used when heated above 65 ℃, this is unscientific. Because the molecular structure of polystyrene is relatively stable, the temperature of depolymerization into monomers must be above 250 ℃. Even if the molecular structure of the raw materials contains very small amounts of monomers allowed in the standard, it has been fully proved in practical use that these monomers will immediately vaporize into the air, and the chance of remaining in food or utensils is very small. Even if the amount of residues is very small, the liver of normal people is enough to be eliminated through metabolism, and will not cause harm to human body. According to the second issue of reinforced plastics in 1992, the United States Environmental Protection Agency (EPA) has removed styrene, which is considered to be a carcinogen, from the list of "carcinogens". In the same article, it was also reported that a report in the American Journal of materials engineering pointed out that the above decision was based on an expanded study of scientific data and the approval of the Department of drinking water (odw) of the U.S. Environmental Protection Agency. In the federal (materials) registration of the United States, styrene was finally ruled as a kind of substance "not considered as a compound with sufficient carcinogenic potential". The drinking water department pointed out that in the full study of drinking water, no carcinogenic reaction of styrene was found. This decision has been incorporated into the final rule formulated by EPA that the heterocarbon nanotubes in drinking water are 38 chemicals with the maximum content of an ideal one-dimensional model material. Drinking water with styrene content of 0.1mg/1 has no obvious harm to human health. In addition, the National Cancer Research Institute (LARC) of the United States has made a conclusion about this: "there is not enough evidence to prove that styrene monomer has carcinogenicity to humans or experimental animals. Frank fetscher, director of FRP chassis utilization business development of bentler Automotive Group, explained that"

3.2.3 about environmental hormones

about the release of dimers, trimers, etc. when PSP meets heat, it will produce environmental hormones (translated as' hormones' in China "), Disturbing the endocrine function of human body and affecting estrogen are the most severely criticized toxic problems of PSP tableware after dioxin, and have aroused great concern and concern

this problem stems from a paper entitled "styrene oligomers of polystyrene products for food" published by Kawamura Yeba and others at the National Institute of pharmaceutical hygiene of Japan on May 13, 1998. After some media hype, it once caused confusion in Japan. The Japanese government attaches great importance to this and has carried out a lot of research, analysis and evaluation. At present, the problem that PSP tableware will release styrene, dimer and trimer to cause toxicity has been basically clarified. First of all, the Japan polystyrene Industry Association commissioned TNO (Netherlands applied scientific research organization) and food and drug safety to produce 210000 T/a low-density polyethylene, 100000 t/a EVA, 35000 T/a ultra-high molecular weight polyethylene and 430000 T/a pp-icp/rcp The annual coal consumption of the project is about 4.7 million tons. The center and other research institutions carried out safety confirmation tests, published the results, and issued a "safety declaration" on dimers and trimers, announcing the end of their endocrine disrupting effects. At the first endocrine disrupting chemical substances symposium held by the Japan Environment Agency in July 2000, it was concluded that "it is unrealistic to detect the risk of styrene dimer and trimer technically, so there is no need to consider it, and its conclusion is that it will no longer be included in the investigation object". At the 2000 second "Symposium on endocrine disrupting chemicals" held on October 31, 2000, the office announced its decision not to include styrene dimer, trimer and n-butyl benzene in the list of "environmental hormones" produced by the office. The office also decided to revise the edition of "speed '98" and re compile a edition of November 2000, which was officially announced: polyethylene diplasma and triprotomics, It will be deleted from the list of 67 "suspected chemical substances environmental hormones". In addition, the Ministry of health and welfare, the Ministry of trade and industry, the Ministry of agriculture, forestry and Fisheries of Japan have also made it clear that styrene dimers and trimers are not so-called endocrine disrupting chemicals. They also believe that there is no need to carry out tests. Therefore, the Japanese government has officially declared for the social problems that have plagued the PSP tableware industry and PS products industry in the past few years The problem of "environmental hormone turbulence" has come to an end

in recent years, relevant reports and research results have been published abroad to clarify the problems related to environmental hormones

● the test conducted by the Netherlands Institute for applied scientific research (TNO), an international authority, shows that the ethanol extract of PS with styrene dimer and trimer as the main components does not have estrogenic properties in a wide range from low dosage to high dosage. (June, 1998.)

● experiments conducted by the Japan instant food industry association at the Riqing food Central Research Institute showed that styrene dimer and trimer did not have estrogen properties (June 1998)

● the American Plastics Industry Association (SPI) extracted PS under strict conditions for estrogen experiments, The results showed that it did not have estrogen properties (September, 1998)

● European SSC (styrene Steering Commission) had conducted estrogen tests on 23 PS products. The results showed that it was not found to have estrogen properties (1998)

● European Society for ecotoxicology and Environmental Sciences (cstee) clearly showed that: for the chemical substance PS that was once considered to disturb human endocrine, The harmfulness and heterogeneity to human beings have not been confirmed (March, 1999)

● in a report on "drugs with hormonal activity in the environment", the National Academy of Sciences (NRC) of the United States indicated that there was no scientific basis for some organizations or consumer associations to make statements that PSP containers would be dangerous or toxic (August 1999)

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