First, Preface to the production of acid degradation bag
According to the Professional Committee of Plastic Recycling and Utilization of the China Plastics Association, one billion plastic bags are used every day to buy vegetables in my country, and more than two billion plastic bags are used every day. While plastic bags bring convenience to people’s lives, they also cause some environmental problems. Therefore, the country now promotes the use of degradable plastics as raw materials for life packaging bags, such as PLA, PBAT, corn starch, etc., and continues to promote the use of environmentally friendly plastic bags to replace traditional plastic materials: PE, PP, PVC, POF, and so on.
Second, the material of the acid degradation bag
- Low pressure polyethylene plastic bag PE
The first and most commonly used plastic bag in my country is made of PE film. Its characteristics are: low cost, good water resistance, but poor gas barrier properties. Wide range of uses: A, garbage bags, bacterial seed bags; B, convenience bags, shopping bags, tote bags, vest bags; C, fresh-keeping bags; D, woven bag inner bags. - High pressure polyethylene plastic bag PEF
High-pressure polyethylene has low density and low melting temperature. It is mostly used in film products: A. Food packaging: cakes, candies, roasted seeds and nuts, biscuits, milk powder, salt, tea, etc.; B. Fiber packaging: shirts, clothing, cotton products, Chemical fiber products; C, daily chemical supplies package. - Polypropylene plastic bag PP
Polypropylene is non-toxic, tasteless, low density, strength, rigidity, hardness, and heat resistance are better than low-pressure polyethylene, and can be used at around 100 degrees. Common acid and alkali organic solvents have little effect on it. Uses: A. Mainly used for packaging textiles, knitted cotton products, clothing, shirts, etc. B. Packaged food, can be used for microwave heating. - Polyvinyl chloride plastic bag PVC
PVC is one of the largest plastic products in the world. It is cheap and widely used. Polyvinyl chloride resin is white or light yellow powder, adding an appropriate amount of plasticizer, can be made into a variety of hard, soft and transparent products. Can be used as: A, gift bags; B, luggage bags, needle cotton packaging bags, cosmetics packaging bags; C, document bags, information bags.
Attention! Polyvinyl chloride plastic bags will decompose hydrogen chloride gas at a higher temperature, such as about 50°C, which is harmful to the human body. Among them, the anti-aging agent containing lead salt will diffuse the lead molecules into the fat when encountering oily foods such as fried dough sticks, fried cakes, fried fish, cooked meat, cakes and snacks. Therefore, polyvinyl chloride plastic bags cannot be used for food.
- Environmental protection plastic bags
Definition: Plastic bags that meet the national standard GB/T21661-2008. Environmentally friendly plastic bags include recycled plastic bags and new plastic bags. Plastic bags added with degradable masterbatch during the production of plastic bags are called degradable plastic bags. Degraded plastic bags (such as PLA, PBAT, corn starch, etc.) can automatically decompose under certain conditions after 90 days.
Third, the composition of the acid degradation bag
The plastic we usually use is not a pure substance, it is made up of many materials. Among them, high molecular polymers (or synthetic resins) are the main components of plastics. In addition, in order to improve the performance of plastics, various auxiliary materials must be added to the polymers.
Synthetic resin: the most important component, which often determines the properties of plastics;
Filler: also called filler, which can improve the strength and heat resistance of plastics;
Plasticizer: increase plasticity, commonly used phthalate esters;
Stabilizer: to prevent decomposition and destruction during processing and use;
Coloring agent: make the plastic have various bright and beautiful colors;
Lubricant: Prevent the plastic from sticking to the mold during molding, and at the same time make the surface of the plastic smooth and beautiful.
Fourth, the production process of plastic bags
Take PE as an example: PE raw materials -> slitting one by one＞color printing one ＞cutting film one by one＞ bag making one by one＞packaged products
PE raw material-plastic film
Production methods: extrusion blow molding method, T-die method, biaxial stretching method, calendering method and casting method. Blowing 5 Mo over fluorine. The process of making 0 particles into a plastic film. The machine used is a film blowing machine.
Five, plastic bag packaging safety
Studies have shown that plasticizers in plastic products are also a carcinogen, while recycled plastics are more likely to ooze out when they come in contact with food, especially oily foods, due to poor technology and other reasons.
Colored plastic bags are recycled plastic bags, and the colorant used usually contains benzoin, which is a strong carcinogen.
Many cooked foods such as fried dough sticks are spread early in thin, pungent recycled plastic bags, and carcinogens ooze out more quickly and are more harmful.
How to identify the toxicity of plastic bags?
- Sensory testing method:
Touch the plastic bag with your hands. If it is non-toxic, it will feel lubricious to the touch, while the toxic plastic bag will feel sticky to the touch. - Jitter detection method:
Hold one end of the plastic bag with your hand and shake it vigorously. Those with a crisp sound are non-toxic, and those with a dull sound are poisonous. - Fire detection method:
The non-toxic polyethylene plastic bag is flammable, the flame is blue, it drips like candle tears when it burns, and it smells of paraffin wax. Toxic polyvinyl chloride plastic bags are not flammable, they will go out immediately after leaving the fire, giving off a pungent smell. - Water testing method
Put the plastic bag in the water, the non-toxic plastic bag can float up; and the toxic ones will not float up.
Sixth, Plastic bags and environmental protection
The hazards of plastic bags
- a) Polluting the environment: The plastic has a stable structure and is not easily degraded.
- b) Huge energy consumption: my country consumes 3 tons of oil for every ton of plastic bags produced
- c) Damage to human health: Toxic plastic bags are used for cooked food packaging, which can easily spoil the food.
- d) Threatened survival: Waste plastic products discarded on land or in water bodies are swallowed as food by animals, leading to their deaths.
- e) Affecting agricultural development: affecting the absorption of nutrients and water by crops, leading to reduced yields.
- f) Occupying a large amount of land: it takes 200 years to degrade it, and the occupied land cannot be restored for a long time.
Eliminate ultra-thin plastic bags, reduce the use of plastic bags, protect the environment, and benefit the country and the people!
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