What is the material of the plastic film?
The plastic film is a film made of polyvinyl chloride, polyethylene, polypropylene, polystyrene, and other resins, used for packaging, and as a coating layer. Plastic packaging and plastic packaging products occupy an increasing share in the market, especially composite plastic flexible packaging, which has been widely used in food, medicine, chemical and other fields, among which food packaging accounts for the largest proportion, such as beverage packaging. , frozen food packaging, cooking food packaging, fast food packaging, etc., these products have brought great convenience to people's lives.
Plastic film use
1. Biaxially oriented polypropylene film (BOPP) use
Biaxially oriented polypropylene film is a transparent flexible packaging material developed in the 1960s. It is a special production line that mixes polypropylene raw materials and functional additives, melts and kneads them into sheets, and then forms a film by stretching. The BOPP film not only has the advantages of low density, good corrosion resistance and good heat resistance of the PP resin, but also has good optical properties, high mechanical strength and abundant raw material sources.
In addition, it can also be applied to the preparation of high value-added functional products such as electrical films and microporous films. Therefore, the development prospects of BOPP films are very broad. By 2004, the production capacity of China's BOPP film production line was 1.9 million tons, and the actual production was about 1.76 million tons.
2. Low density polyethylene film (LDPE) use
Low density polyethylene films are generally produced by both blow molding and casting processes. The thickness of the cast polyethylene film is uniform, but it is rarely used because of its high price. Blow-blown polyethylene film is blown from blow molding PE particles by a blow molding machine, and has a lower cost, so it is the most widely used. Low-density polyethylene film is a translucent, lustrous, softer film with excellent chemical stability, heat sealability, water resistance and moisture resistance, freeze-resistant, boilable, and agricultural application. Membrane can be divided into shed film, mulch film, bitter cover film, and green film.
3. Polyester film (PET) use
PET polyester film is abbreviated as PET film, a thermoplastic engineering plastic. It is characterized by high temperature resistance, good printing, easy processing, and good voltage insulation. It is made of polyethylene terephthalate as raw material, and is made into a thick film by extrusion method and then made into a film material by biaxial stretching. It is a colorless, transparent and lustrous film with excellent mechanical properties, high rigidity, hardness and toughness, puncture resistance, friction resistance, high temperature and low temperature resistance, chemical resistance, oil resistance, air tightness and aroma retention. Good, it is one of the commonly used barrier composite film substrates. However, the price of the polyester film is relatively high, and the thickness is generally 0.12 mm, which is commonly used as an outer layer material for retort packaging, and has good printability.
4, nylon (Pa) plastic film use
The chemical name of nylon is polyamide (Pa). At present, there are many varieties of nylon produced industrially. Among them, the main varieties used to produce film are Pa6, Pa12, Pa66 and so on. Nylon film is a very tough film with good transparency, good gloss, high tensile strength, high tensile strength, good heat resistance, cold resistance, oil resistance and organic solvent resistance. Excellent abrasion resistance and puncture resistance, soft and oxygen barrier, but poor barrier to water vapor, high moisture absorption and moisture permeability, poor heat sealability, suitable for packaging hard articles, such as greasy Sex food, meat products, fried foods, vacuum packed foods, cooked foods, etc.
5. Cast polypropylene film (CPP) use
The cast polypropylene film can be divided into a general-purpose CPP film, an aluminized CPP film and a cooking-grade CPP film, and has excellent transparency, uniform thickness, and uniform longitudinal and lateral properties, and is generally used as an inner layer material of the composite film. The thickness of ordinary CPP film is generally between 25 and 50 μm. After compounding with OPP, the transparency is good, the surface is bright, and the hand feel is firm. The general gift packaging bag uses this material. This film also has good heat sealability. The thickness of the cooking grade CPP film is generally between 60 and 80 μ m. It can withstand high temperature cooking at 121 ° C for 30 min. It has good oil resistance and air tightness, and the heat sealing strength is high. The inner layer of the general meat packaging is uniform. A cooking grade CPP film is used.
6, aluminum-plated plastic film use
The aluminized film is a composite flexible packaging material formed by plating a thin layer of metal aluminum on the surface of the plastic film by a special process.
The surface of the film is coated with aluminum to prevent light and ultraviolet radiation, which not only prolongs the shelf life of the content, but also improves the brightness of the film. It replaces the aluminum foil to a certain extent, and has the advantages of low cost, good appearance and good barrier property. Aluminized film is widely used in composite packaging. It is mainly used in dry and puffed food packaging such as biscuits and on the outer packaging of some medicines and cosmetics.
