What is food grade plastic?
"Food-grade plastic" is defined as food-safe plastic. The term refers to any plastic suitable for contact with consumable food or beverage products. Since some acidic foods or liquids can leach chemicals from the container, it is important to store them in the proper container.
The Food, Drug, and Cosmetic Act, adopted by the U.S. Food and Drug Administration (FDA), defines food contact substances as substances used in food manufacturing, packaging, packaging, storage, and transportation applications without a risk of technical effects occurring in food materials. The "technical effects" mentioned in this definition include leaching, which affects the taste of food and beverages and poses a potential risk to human health when the affected materials are consumed.
What are the food grade raw materials?
Common food-grade plastics include PET (polyethylene terephthalate), HDPE (high density polyethylene), LDPE (low density polyethylene), PP (polypropylene), PS (polystyrene), PC, etc.
1, PET (polyethylene terephthalate)
Thermoplastic polyester, with excellent toughness, tensile, impact strength, wear resistance, electrical insulation.
Due to its good toughness, light weight, air permeability, acid and alkali resistance, water resistance, oil resistance and other characteristics, it has become a common material for soda, juice, carbonated beverages, edible oil retail packaging in recent years. Shrinkage rate of 70%, general PET is not heat resistant. Below 80 degrees Celsius can maintain no deformation, no toxin release.
PET is often used as a mineral water bottle, carbonated beverage bottle material. Carbonated beverages, tea, juice, packaged drinking water, wine and soy sauce and other products can also choose this material, in addition, such as detergent, shampoo, food oil, condiments, sweet food, medicine, cosmetics, and alcoholic beverage packaging bottles, have been used in a large number of bottles.
2, HDPE (high density polyethylene)
HDPE is a highly crystalline, non-polar thermoplastic resin. The appearance of the original HDPE is milky white, and it is translucent to a certain extent in the meager section. PE has excellent resistance to most life and industrial chemicals, is the most widely used plastic in industry and life, generally divided into high density polyethylene (HDPE) and low density polyethylene (LDPE) two. PE has excellent resistance to acidity and alkalinity. HDPE is higher than LDPE melting point, hardness, and more resistant to corrosive liquid erosion. Certain types of chemicals produce chemical decay agents, such as corrosive oxidants (concentrated nitric acid), aromatic hydrocarbons (xylene) and halogenated hydrocarbons (carbon tetrachloride). The polymer is non-hygroscopic and has good vapor resistance, which can be used for packaging purposes. HDPE has good electrical properties, especially the high dielectric strength of the insulation, making it suitable for wire and cable.
At present, the plastic bags and various translucent or opaque plastic bottles seen on the market are almost all made by PE, such as cleaning agents, shampoo, bath milk, cooking oil, pesticides... Etc., most of them are held in HDPE bottles. LDPE is ubiquitous in modern life, but not because of the containers it makes, but because of the plastic bags you can see everywhere. Most plastic bags and plastic films are made of LDPE.
In terms of pipe products, HDPE is more suitable for making pipes than LLDPE and LDPE, LDPE pipe has poor pressure resistance, poor aging resistance, soft texture and the pipes are not easy to connect, so it is not suitable for pressure supply water pipes, and HDPE pipe has excellent impact resistance, excellent aging resistance, cracking resistance and corrosion resistance.
3, LDPE (Low density polyethylene)
Low density polyethylene is a synthetic resin obtained by free radical polymerization of ethylene under high pressure, so it is also called "high pressure polyethylene". Because the molecular chain contains more long and short branch chains, the product density is small, soft, low temperature resistance, impact resistance is good; Has good chemical stability, in addition to strong oxidizing acid, under normal circumstances, acid, alkali, salt corrosion, has excellent electrical insulation performance, low water vapor transmission rate, good fluidity, has good molding processing performance, Suitable for injection molding, extrusion, blow molding, rotary forming, coating, foaming process, hot forming, hot air welding, hot welding and other thermoplastic processing processes.
Low density polyethylene is mainly used to make film products, in agriculture with film (such as ground cover film, greenhouse film, etc.), packaging film (can be used for candy, vegetables, frozen food and other packaging), liquid packaging with blow molding (coated) film (can be used for cattle
Milk, soy sauce, juice, tofu, soy milk and other packaging), heavy packaging bags, shrink packaging film, elastic film, lining film, construction film and general industrial packaging film and food bags have a wide range of applications, low density polyethylene can also be used in the production of blow molding hollow products, such as food containers, medicine, cosmetics, chemical products containers, tanks and so on.
4, PP (polypropylene)
Polypropylene (PP) is a thermoplastic addition polymer made from a combination of propylene monomers. A wide range of applications, including consumer packaging, plastic parts for the automotive industry and textiles. Easy to obtain and relatively cheap.
It has high flexural strength and relatively smooth surface. PP moisture-proof, low water absorption, in a variety of acids and alkalis have good chemical corrosion resistance, with good impact strength.
The microwave lunch box is made of this material, resistant to 130 ° C high temperature, poor transparency, this is the only plastic box that can be put into the microwave oven, and can be reused after careful cleaning.
PP and PE can be said to be two brothers, but some physical and mechanical properties are better than PE, so bottlers often use PE to make bottles, caps and handles with greater hardness and strength of PP to manufacture. PP melting point up to 167℃, heat resistance, products can be sterilized by steam is its characteristics. PP bottles, the most common is soy milk, rice milk bottles, and used to hold 100% pure juice, yogurt, juice drinks, dairy products (such as pudding), etc., larger containers, such as buckets, trash cans, laundry tanks, baskets, baskets, etc., are made of PP.
How to distinguish food grade plastic products
01 Look at the material from plastic recycling
Food grade plastics are divided into seven grades, from one to seven, the greater the number, the stronger the hardness. The plastic recycling sign is a triangular symbol, usually on the bottom of the plastic container. There are numbers from 1 to 7 inside the triangle, each number represents a different material, if the product is made of several different materials, it indicates the main, basic material of the product.
02 Simple identification of plastic products
Vision: The surface of qualified plastic products is smooth, the color is clear and transparent, and the flexibility 靭 is good; The color of unqualified plastic products is cloudy.
Smell: qualified plastic products are odor-free at room temperature; Substandard plastic products have a pungent or unpleasant smell.
Touch: Qualified plastic products feel smooth, flexibility is good, if the feel is not smooth, especially sticky must not be loaded with food, because it is likely to add a lot of additives.
