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Toxicity identification of convenient bag
Commonly used food convenience bags are made of polyethylene film, which is non-toxic and can be used to hold food. There is also a membrane made of PVC, which is not toxic in itself, but the additives added according to the purpose of the membrane are often harmful to the human body and have certain toxicity. Therefore, this film and the convenient bag made of this film are not suitable for holding food. If you want to identify PVC convenience bags and polyethylene convenience bags, you can use the following simple methods to identify them.
Polyethylene film (nontoxic)
The film is milky white, translucent (especially obvious after being folded several times), smooth to the touch, as if the surface is coated with a layer of wax, which is hard to shake, brittle in sound, flammable in case of fire, yellow in flame, dripping with mucus when burning, and smelling of candles when burning.
PVC film (usually toxic)
If no pigment is added, it is transparent, the surface feels a little sticky, shaking badly and the sound is low. It is not easy to burn in case of fire, and it goes out immediately after leaving the flame, and the flame is green.
Edit the history of this convenient bag.
A photographer's experiment in a darkroom led to the first plastic. Alexander Parks has many hobbies, and taking photos of convenient bags (4) is one of them. In the19th century, people can't buy ready-made photographic films and chemicals as they do today. They must always make what they need. So every photographer must also be a chemist. One of the materials used in photography is "collodion", which is a kind of "nitrocellulose" solution, that is, nitrocellulose solution in alcohol and ether. At that time, it was used to stick photosensitive chemicals on glass and make photographic film equivalent to today. In the 1950s of 19, Parks studied different methods to treat collodion. One day, he tried to mix collodion with camphor. To his surprise, a flexible hard material was produced after mixing. Parks called this substance "Paxsin", which was the earliest plastic. Parks made all kinds of objects with Paxsin: combs, pens, buttons and jewelry patterns. However, Parks is not very business-conscious. He lost money in his business venture. In the 20th century, people began to explore new uses of plastics. Almost everything in the house can be made of some kind of plastic. Leave it to other inventors to continue to develop Parks' achievements and profit from them. John wesley Heath, a printer from New York State, saw this opportunity in 1868, when a billiards company complained about the shortage of ivory. Heath improved the manufacturing process and gave Paxsin a new name-celluloid. He got a ready-made market from billiards manufacturers, and soon he made various products out of plastic. Early plastic caught fire easily, which limited the range of products made from it. The first plastic that can successfully resist high temperature is "Beckett". Leo Baekeland obtained this patent on 1909. 1909, phenolic plastics were synthesized for the first time in Baekeland, USA. In 1930s, nylon came out again, which was called "a kind of fiber composed of coal, air and water, thinner than spider silk, harder than steel and better than silk". Their appearance laid the foundation for the invention and production of various plastics. Due to the development of petrochemical industry in World War II, the raw material of plastics replaced coal with oil, and the plastic manufacturing industry also developed rapidly.
In this paragraph, edit the hazards of convenient bags.
harm
Plastic is a very light substance, which can be softened by heating at a very low temperature and made into various shapes at will. Plastic products are bright in color, light in weight, not afraid of falling, economical and durable. Its appearance not only brings a lot of convenience to people's lives, but also greatly promotes the development of industry. However, plastics were invented less than 100 years ago. If people were ecstatic about their birth at that time, now they have to deal with these things that are full of life and pose a great threat to the living environment of mankind. Plastic is a chemical petroleum product extracted from petroleum or coal, and it is difficult to degrade naturally once it is produced. Plastics will not rot and degrade after 200 years underground, and a large amount of plastic garbage will destroy the permeability of soil, harden the soil and affect the growth of plants. If domestic animals eat plastic mixed with feed or left in the wild by mistake, they will also die because of digestive tract obstruction. At present, the annual output of plastics in China is 300,000 tons and the consumption is more than 6 million tons. The annual output of plastics in the world is 654.38 billion tons. If the annual plastic waste is calculated as 654.38+05%, the annual plastic waste in the world is 6.5438+05 million tons, and the annual plastic waste in China is more than 6.5438+00 million tons, accounting for 40% of the waste. So a lot of waste plastics are buried underground as garbage, which undoubtedly gives the already scarce cultivated land. Plastics not only bring convenience to people's lives, but also bring irreparable troubles to the environment. People call the disaster that plastics bring to the environment "oil pollution". At present, many countries use incineration (heat energy recovery) or reprocessing (product recovery) to treat waste plastics. These two methods can recycle waste plastics and save resources. However, because waste plastics will produce gases harmful to human body and pollute the environment when they are burned or reprocessed, it can be said that the treatment of waste plastics is still a headache in environmental protection work.
Completely restricted use
The General Office of the State Council issued the Notice on Restricting the Production, Sales and Use of Plastic Shopping Bags, requiring all supermarkets, shopping malls, bazaars and other retail places to implement a system of paid use of plastic shopping bags, and plastic shopping bags are not allowed to be provided free of charge. In addition, passenger trains, passenger ships, buses, planes, stations, airports and tourist attractions are not allowed to provide ultra-thin plastic shopping bags (packaging bags) to passengers and tourists. Plastic shopping bags must be clearly marked, and enterprises are encouraged to provide bags free of charge. Plastic shopping bags must be clearly marked and collected separately. According to the notice, retail outlets are not allowed to provide plastic shopping bags free of charge or include them in the total price of goods. At the same time, relevant departments will formulate specific management measures for the paid use of plastic shopping bags in commodity retail places, and gradually form a market environment for the paid use of plastic shopping bags. The circular advocates carrying cloth bags, reusing shopping baskets, reusing durable shopping bags and reducing the use of convenient bags. At the same time, enterprises should simplify commodity packaging and choose more green packaging bags. The circular also encourages enterprises and social forces to provide reusable shopping bags such as cloth bags for the masses free of charge. The production and sale of ultra-thin convenient bags are prohibited nationwide. From June 1 2008, a tax policy to curb waste plastic pollution will be formulated, and the production, sale and use of plastic shopping bags (ultra-thin plastic shopping bags) with a thickness of less than 0.025mm will also be banned throughout the country. From June this year 1, convenience bags will be paid for in major shopping malls across the country, and customers must pay to prevent the overflow of convenience bags.
This paragraph edits the environmental protection convenient bag (hdpe).
The invention of the convenient bag has brought great convenience to human life, but more and more people don't know how to use it effectively, which leads to a convenient and environmentally friendly convenient bag.
The globalization of bag pollution calls on everyone to use environmentally-friendly convenient bags as much as possible and make their own contributions to our bluer sky. Compared with the traditional convenience bag, it has the following advantages: 1, water solubility can be designed and selected, completely soluble in water, non-toxic and pollution-free; 2. Strong tensile strength and good tension; 3, high transparency and good luster; 4, high softness and good touch; 5. Good oil resistance, solvent resistance, heat sealing and printability; 6. Low permeability coefficient and good gas barrier; 7. Plastic snap buttons or adhesive bags can be added; 8. Excellent antistatic performance, no vacuuming, etc. The most common packaging in daily shopping, the main component of white pollution.