Six kinds of toxic and harmful substances brought by plastics
Hydrogen cyanide, also known as hydrocyanic acid, can be poisoned by inhalation of respiratory tract or by ingestion.
Benzene-containing compounds Benzene-containing compounds are the most common damage to the human nervous system, which is manifested as dizziness, headache, fatigue, insomnia or dreaminess, and are also toxic to the human hematopoietic system. Benzene has been identified as a chemical that can cause human leukemia.
PVC plastic products will produce hydrogen chloride gas after combustion. People will cause cough, sneezing, shortness of breath, chest tightness, runny nose and tears after contact. Inhalation of high concentration PVC can cause pulmonary edema, and long-term contact can induce chronic bronchitis.
Toluene diisocyanate (TDI) is a low molecular compound, which is widely used in industrial fields, especially in foam, paint, coatings and plastics industries. Its harm to human body is mainly the adverse effects on respiratory system, which can lead to cough, chest tightness, shortness of breath, asthma and other symptoms.
Phthalate PVC contains phthalate components. Experts have found that soft plastic toys and children's products containing phthalates may be put into children's mouths. Phthalate esters will cause damage to the liver and kidneys after entering the human body for a long time, and may also lead to precocious puberty in children. Studies have shown that phthalates play a similar role to estrogen in human and animals, which can interfere with endocrine, reduce the amount and number of * * * * in men, make the exercise ability of * * * low, cause abnormal morphology of * * *, and seriously lead to testicular cancer, which is the chief culprit of male reproductive system problems.
A new study on bisphenol A shows that the old and new plastic bottles filled with room temperature water release the same amount of bisphenol A. But when scientists fill these bottles with boiling water, the release rate of bisphenol A is 54 times higher than that before heating. Bisphenol A is another name for environmental hormone and endocrine interferon, which can produce similar effects to sex hormones.
Which plastics are poisonous? 5 points
Food bags on the market can be packed dry, wet, raw and cooked, which is safe and non-toxic. Plastic bags for packaging food in food factories and preserves factories are of course non-toxic. Plastic bags used to pack daily necessities, clothes, shoes and socks, electrical appliances and hardware parts may be toxic and not suitable for food. Non-toxic plastic bags are generally made of polyethylene and toxic plastic bags are made of polyvinyl chloride. Because there is unpolymerized vinyl chloride monomer in PVC resin, it is a compound that will be toxic to human body. In addition, in the process of processing PVC resin into plastic bags, some auxiliary materials such as plasticizers, stabilizers, pigments, etc. Some auxiliary materials are toxic. These toxic substances are easily extracted by oil or water in food and eaten with food, which is harmful to human health. PVC resin itself is non-toxic. If the free vinyl chloride monomer is reduced to a few in the production of PVC resin, and the nontoxic auxiliary materials are strictly selected in the production of finished products, nontoxic PVC plastic bags can be made. It is generally difficult to distinguish polyethylene plastic bags from PVC plastic bags. By burning, it is easy to identify. Polyethylene can burn, the flame is blue, the upper end is yellow, and it emits paraffin smell when burning; PVC is extremely difficult to burn. When it caught fire, it was yellow-green outside and smelled of hydrochloric acid. Whether plastic bags are toxic in use is also related to the method of use. Some food bags are printed with words such as trademarks. It is unsafe to turn the food bag upside down and let the food be stained with these pigments.
What kinds of plastics are there, which are toxic and which are non-toxic?
Classification by usage characteristics
According to the different use characteristics of various plastics, plastics are usually divided into three types: general plastics, engineering plastics and special plastics.
① Ordinary plastics
Generally, it refers to plastics with large output, wide use, good formability and low price. There are five kinds of general plastics, namely polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and acrylonitrile butadiene styrene (ABS)[3]. These five kinds of plastics account for the vast majority of plastic raw materials, and the rest can basically be classified as special plastic varieties, such as PPS, PPO, PA, PC, POM and so on. It is rarely used in daily life products, and is mainly used in high-end fields such as engineering industry and national defense technology, such as automobiles, aerospace, architecture, communications and other fields. Plastics can be divided into thermoplastics and thermosetting plastics according to their plasticity. Usually, thermoplastic products can be recycled, but thermosetting plastics can't. According to the optical properties of plastics, they can be divided into transparent, translucent and opaque raw materials, such as PS, PMMA, AS and PC, which belong to transparent plastics, while other plastics are mostly opaque plastics.
Properties and uses of common plastic varieties
1. Polyethylene: Commonly used polyethylene can be divided into low density polyethylene (LDPE), high density polyethylene (HDPE) and linear low density polyethylene (LLDPE)[4]. Among the three, HDPE has better thermal, electrical and mechanical properties, while LDPE and LLDPE have better flexibility, impact properties and film-forming properties. LDPE and LLDPE are mainly used in packaging film, agricultural film and plastic modification. And HDPE is widely used in films, pipes, daily necessities for injection and other fields.
2. Polypropylene: Relatively speaking, polypropylene has more varieties, more complex uses and more fields. The main varieties are homopolypropylene, block polypropylene (copp) and random polypropylene (rapp). According to different uses, homo is mainly used in drawing, fiber, injection molding, BOPP film and other fields.
3.PVC: Because of its low cost and self-flame retardant characteristics, it is widely used in the construction field, especially in sewer pipes, plastic steel doors and windows, plates, artificial leather and so on.
4. Polystyrene: As a transparent raw material, it is widely used, such as car lampshades, daily transparent parts, transparent cups and cans.
5.ABS is a widely used engineering plastic with excellent physical, mechanical and thermal properties. Widely used in household appliances, panels, masks, components, accessories and so on. Especially household appliances, such as washing machines, air conditioners, refrigerators, electric fans, etc. It is also widely used in plastic modification.
② Engineering plastics
Generally speaking, it refers to plastics that can withstand certain external forces, have good mechanical properties, high and low temperature resistance and good dimensional stability, and can be used as engineering structures, such as polyamide and polysulfone.
Among engineering plastics, it can be divided into general engineering plastics and special engineering plastics.
General engineering plastics include: polyamide, polyoxymethylene, polycarbonate, modified polyphenylene ether, thermoplastic polyester, ultra-high molecular weight polyethylene, methylpentene polymer, vinyl alcohol polymer and so on.
Special engineering plastics can be divided into crosslinking type and non-crosslinking type. Cross-linking types include: polyamino bismaleimide, polytriazine, cross-linked polyimide, heat-resistant epoxy resin and so on. Non-crosslinked ones include polysulfone, polyethersulfone, polyphenylene sulfide, polyimide, polyetheretherketone (PEEK) and so on.
③ Special plastics
Generally, it refers to plastics with special functions, which can be used in special application fields such as aviation and aerospace. For example, fluoroplastics and silicone resins have outstanding special functions such as high temperature resistance and self-lubrication, while reinforced plastics and foamed plastics have special properties such as high strength and high cushioning. These plastics belong to the category of special plastics.
A. reinforced plastics:
The raw materials of reinforced plastics can be divided into three types in appearance: granular (such as calcium-plastic reinforced plastics), fibrous (such as glass fiber or glass cloth reinforced plastics) and flaky (such as mica reinforced plastics). According to the materials, it can be divided into three types: cloth reinforced plastics (such as rag reinforced plastics or asbestos reinforced plastics), inorganic mineral filled plastics (such as timely or mica filled plastics) and fiber reinforced plastics (such as carbon fiber reinforced plastics).
. Foam:
Foam plastics can be divided into hard, semi-hard and soft foams. & gt
Is plastic poisonous?
There are many kinds of plastics, polyethylene PE and polystyrene PS are just two of them. PS is more toxic than the two. If it is eaten in the stomach, it will not have much impact on the human body if it can be excreted with feces, unless it is hard plastic, which is easy to scratch the stomach wall and intestines. Generally speaking, cups that meet national standards are non-toxic, such as PET materials, which can only be decomposed at a high temperature above 200 degrees Celsius. So if you buy plastic cups from regular manufacturers, you can use them with confidence. As far as I know, the materials used to make this cup are PE, PP, PET, and other PVC and ps. If we have to treat the disease, the most serious thing is to inhale the gas produced by burning plastics, such as toluene produced by burning polystyrene. Inhalation of a small amount of this substance can cause blindness, vomiting and other symptoms. The combustion of PVC will also produce toxic gas hydrogen chloride. In addition to combustion, high temperature environment will lead to the decomposition of toxic components in plastics, such as benzene rings. The substances produced by pure plastic materials such as PE and PP will not cause too much harm to the human body for the above reasons. However, white pollution is also a serious problem because plastics are difficult to decompose under natural conditions. After all, plastics are not natural, they are all synthetic by human beings. The principle of producing toxic components is that polymers undergo energy decomposition, and their monomers are generally highly polar, which is easy to destroy living tissues.
Are all plastic products toxic?
Plastic products used in daily life are not toxic. Like papermaking, paper is not toxic, but the papermaking process will produce pollution and use some toxic substances. The raw materials used to make plastics are somewhat toxic, but the plastics made are high molecular substances and have no toxicity. However, it does not rule out that some unscrupulous merchants add recycled materials or excessive additives to plastics.
Distinguish toxic plastic products
There is a plastic material called PET in the mineral water bottle, which is safe once used. If it is reused for thrift or convenience, there will be a cancer crisis.
All mineral water bottles have a triangle with an arrow at the bottom and a number in the triangle.
General mineral water bottle, bottom marked1; Nongfu Spring is 4 liters, with the bottom marked 2; Plastic heat-resistant cup for making tea, the bottom of which is marked with 5.
PET polyethylene terephthalate
Common mineral water bottles, carbonated beverage bottles, etc. Heat resistance to 70℃ is easy to deform, and substances harmful to human body are melted out. Plastic product 1 may release carcinogen DEHP after using 10 months. Can't put it in the car to bask in the sun; Don't pack alcohol, oil and other substances.
HDPE high density polyethylene
Common white medicine bottles, cleaning products, bath products. Don't use it as a cup, or as a storage container for other items. If the cleaning is not thorough, don't recycle it.
polyvinyl chloride
Common raincoats, building materials, plastic films, plastic boxes, etc. Excellent plasticity and low price, so it is widely used, and can only resist heat of 865438 0℃. It is easy to produce harmful substances at high temperature and is rarely used in food packaging. It is difficult to clean, and it is easy to remain, so don't recycle it. Don't buy packaged drinks.
PE Chu ethylene
Common cling film, plastic film, etc. Harmful substances will be produced at high temperature, and toxic substances may cause diseases such as breast cancer and birth defects of newborns after entering the human body with food. Don't put plastic wrap in the microwave.
polypropylene
Common soybean milk bottles, sour milk bottles, fruit juice bottles, microwave lunch boxes. With a melting point as high as 167℃, it is the only plastic box that can be put into a microwave oven and can be reused after careful cleaning. It should be noted that some microwave lunch boxes are made of No.5 PP, but the cover is made of 1 PE. Because PE is not resistant to high temperature, it can't be put in the microwave oven with the box.
polystyrene
Common instant noodle boxes and fast food boxes in bowls. Can't put it in the microwave oven, so as not to release chemicals when the temperature is too high. After being filled with acid (such as orange juice) and alkaline substances, carcinogens will decompose. Avoid packing hot food in fast food boxes. Don't cook bowls of instant noodles in the microwave oven.
Other classes of PC
Common kettles, space cups and milk bottles. Department stores often use cups made of this material as gifts. It is easy to release bisphenol A, a toxic substance harmful to human body. Don't heat it when using it, and don't directly bask in the sun.
Is plastic poisonous?
This question is too difficult. As far as I know, I will answer from several aspects from a professional point of view. Plastics are both toxic and non-toxic. This issue has been debated in academia and industry. Just look at the process, formula, synthesis technology and application. Not every plastic is poisonous. Like PP, it is often used to make cups, and the sealing ring made of stainless steel is also made of plastic or rubber. You can usually see these signs on plastic products. Let me talk about it first. The icon 1 is: PET polyethylene terephthalate, which is commonly found in mineral water bottles and carbonated beverage bottles. Heat resistance to 70 degrees is easy to deform, and substances harmful to human body are melted out. Plastic product 1 may release carcinogen DEHP after using 10 months. It can't be put in the car to bask in the sun, nor can it be used to hold substances such as wine and oil. Figure 2 shows: HDPE high-density polyethylene, which is commonly used in white medicine bottles, cleaning products, bath products, etc. But it can't be used as a cup, and it can't be used as a storage container to hold other items. The cleaning is not thorough and cannot be recycled. Icon 3 is: PVC and polyvinyl chloride, which are commonly found in raincoats, building materials, plastic films, plastic boxes and so on. This kind of plastic has excellent plasticity and low price, so it is widely used. It can only resist heat of 8 1 degree, and it is easy to produce bad substances at high temperature, so it is rarely used in food packaging. It is difficult to clean and easy to remain, so it cannot be recycled. Don't buy packaged drinks. Figure 4 shows PE polyethylene, which is commonly found in plastic wrap and plastic film. Harmful substances will be produced at high temperature, and toxic substances may cause diseases such as breast cancer and neonatal congenital defects after entering the human body with food. Never put plastic wrap in the microwave oven. Icon 5 is: PP polypropylene, which is commonly found in soybean milk bottles, yogurt bottles, juice bottles and microwave lunch boxes. The melting point is as high as 167 degrees. It is the only plastic box that can be put into the microwave oven and reused after careful cleaning. It should be noted that some microwave oven boxes are made of No.5 PP, but the cover is made of 1 PE. Because PE is not resistant to high temperature, it can't be put in the microwave oven with the box. Icon 6 is: polystyrene, which is often used for instant noodle boxes and fast food boxes in bowls. But it can't be placed in the microwave oven, so as not to release chemicals when the temperature is too high. After being filled with acid (such as orange juice) and alkaline substances, carcinogens will decompose. Avoid packing hot food in fast food boxes. Don't cook bowls of instant noodles in the microwave oven. Icon 7 is: PC and other plastics, which are commonly found in kettles, space cups and milk bottles. Department stores often use cups made of this material as gifts. It is easy to release bisphenol A, a toxic substance harmful to human body. Don't heat it when using it, and don't directly bask in the sun. We now know that some waste plastics are toxic, and some are not toxic after paying attention to details when using them. On many occasions, everyone likes to use plastic bottles to hold drinks, but drinks taste like plastic, indicating that people drink plastic instead of drinks. The most poisonous are No.3, No.6 and No.7. If you find these three-digit drinks at the bottom of the bottle, don't drink them. When it comes to plastics, we are all concerned about environmental protection. Since its appearance, plastics have been widely used, but at the same time it has also caused serious environmental problems. Plastic waste is difficult to decompose naturally, which leads to the increase of solid waste; If it flows into the ocean, it will also lead to ingestion, suffocation and poisoning of marine life, affecting marine ecology; Burning plastic waste can also cause air pollution. Some plastics, such as polyvinyl chloride (PVC) and polycarbonate, may release harmful substances or endocrine interferon under certain conditions, thus endangering the reproductive function of organisms. Therefore, reducing the use of plastics has become an important task of environmental protection. Unfortunately, the recycling of plastics is not easy, and the implementation effect is not satisfactory. Compared with metal recycling, the biggest problem of plastic recycling is that it is difficult to sort automatically by machine, and the process involves a lot of manpower. In addition to containers usually made of a single plastic, many plastic products are assembled from a variety of different materials, and the cost of disassembling them may be higher than that of recycling plastic. In addition, some plastics recycling has no economic value, such as expanded polystyrene. This kind of plastic waste is usually buried or burned. I hope this answer is helpful to you.
How to identify whether plastic products are toxic?
The first is the identification number on the plastic.
No.65438 +0- Pets: bottles of mineral water and carbonated drinks
Don't recycle the hot water in the beverage bottle.
The heat resistance is 65℃, and the cold resistance is -20℃. It is only suitable for warm or frozen drinks and high-temperature liquids, otherwise it is easy to deform when heated, and substances harmful to the body are dissolved out. Moreover, scientists have found that plastics 1 use 10 may release carcinogens and be toxic to testicles.
Therefore, drink bottles should be discarded when they are used up. They should not be used as drinking cups or as storage containers for other items, so as not to cause health problems.
Second: high-density polyethylene: cleaning and bathing products.
If the cleaning is not thorough, it is recommended not to recycle.
It can be reused after careful cleaning, but these containers are usually not easy to clean, leaving the original cleaning supplies and becoming a hotbed of bacteria. It is best not to recycle them.
No.3-PVC: rarely used for food packaging.
It's best not to buy it.
This material is easy to produce harmful substances at high temperature, and even it will be released during the manufacturing process. Poisons entering the body with food may cause diseases such as breast cancer and birth defects of newborns. At present, containers made of this material are rarely used for packaging food. If it is in use, don't let it get hot.
No.4-LDPE: cling film, plastic film, etc.
Food enters the microwave oven and the plastic package is torn off.
Heat resistance is not strong. Generally qualified PE plastic wrap will melt when the temperature exceeds 1 10℃, leaving some insoluble plastic preparations in the body. Moreover, food is wrapped and heated with plastic wrap, and the oil in food can easily dissolve the harmful substances in plastic wrap. Therefore, before putting food into the microwave oven, you must first remove the wrapped plastic wrap.
No.5 PP: microwave lunch box, fresh-keeping box.
Take off the cover before entering the microwave oven.
Because microwave lunch boxes generally use PP (polypropylene, high temperature resistance 120℃, low temperature resistance -20℃) for microwave ovens, because of cost reasons, lids are generally not used. When put into the microwave oven, the cover must be removed before use. Because all kinds of bayonet fresh-keeping boxes use transparent PP instead of special PP, they can't be put into the microwave oven.
The only plastic box that can be put into the microwave oven can be reused after careful cleaning. It should be noted that some microwave lunch boxes are indeed made of No.5 PP, but the lid is made of No.0 PE/kloc-0. Because PE is not resistant to high temperature, it can't be put in the microwave oven with the box. To be on the safe side, open the lid before putting the container in the microwave oven.
No.6 -PS: Bowl instant noodle box, fast food box
Don't cook a bowl of instant noodles in the microwave oven.
Heat-resistant and cold-resistant, but it can't be put into the microwave oven to avoid releasing chemicals at high temperature (it will be released when it is resistant to 70℃). Moreover, it can not be used to load strong acids (such as orange juice) and strong alkaline substances, because it will decompose polystyrene which is not good for health and easy to cause cancer. Therefore, you should try to avoid packing hot food in fast food boxes.
No.7 computer: kettle, water cup, milk bottle
PC glue releases bisphenol A when heated.
A widely used material, especially in milk bottles, is controversial because it contains bisphenol A. ..
Lin Hanhua, an associate professor in the Department of Biochemistry of City University of Hong Kong, said that in theory, as long as bisphenol a 100% is converted into plastic structure in the process of manufacturing PC, it means that the product does not contain bisphenol A at all, let alone is released. However, if a small amount of bisphenol A is not converted into the plastic structure of PC, it may be released into food or drink. Therefore, when using this kind of plastic container, we should be especially careful.
Related connection
Plastic cups containing "7" should be washed with baking soda powder for the first time.
The higher the temperature, the more bisphenol A remaining in PC is released and the faster it is. Therefore, PC water bottles should not be used to hold hot water, so as not to increase the release speed and concentration of bisphenol A (if any). If your kettle number is 7, the following methods can reduce the risk:
● Do not heat when using. ● Do not use dishwasher or bowl dryer to clean the kettle.
● Don't let the kettle be exposed to direct sunlight.
● Before the first use, wash it with baking soda powder and warm water and bake it naturally at room temperature. Because bisphenol A will release more during the first use and long-term use.
● If the container is injured or damaged, it is recommended to stop using it, because if there are tiny pits on the surface of plastic products, it is easy to hide bacteria.
● Avoid reusing aging plastic appliances.
The second is to observe by some physical methods.
Generally speaking ... >>
How to identify toxic plastic products in life?
I learned it when I was studying plastic material processing. It is really difficult for ordinary people to have a professional appraisal. Let me tell you some simple and convenient methods. First of all, generally speaking, the darker the color, the more toxic the plastic is, because the darker the pigment is, the more toxic it is. Another important reason for dyeing plastic is that the raw material is waste plastic, in order to cover up the original color. The second is smell. As long as plastic smells, it will never hold food. The smell is generally the smell of additives, pigments and other auxiliary materials or residual monomers added to the product. The third is touching. Generally speaking, the plastic used to hold food feels smooth and shiny. If it is not smooth and sticky, you must not hold food, because there are too many additives in it, which may account for more than 50%. Next, I will briefly talk about some materials. Usually, PP (polypropylene) and PE (polyethylene) are used to package food. These two are safer. The plastic wrap in supermarkets is generally PP, and the hot water pipes at home are also PP, because it is necessary to ensure non-toxicity. Generally, PC (polycarbonate) is a plastic cup used to hold hot water, but this one is also used to hold CDs, so be careful about waste recycling. Sewer pipes are generally PVC. I forgot to say that the thinner and softer the plastic, the worse the more additives. The above is a simple explanation. We have studied polymer materials and plastics for a semester and have a general understanding. If you are original and satisfied with the above personal views, you will get extra points. It's tiring to type so many words on your mobile phone!