The use of the seven plastic film
PVA coated high barrier plastic film polyvinyl alcohol is a highly barrier film formed by coating a modified polyvinyl alcohol water soluble liquid on a polyethylene substrate. Due to the good barrier property and environmental protection requirement of the polyvinyl alcohol, the market prospect of this kind of packaging material is very bright, and there is broad market space in the food industry. Biaxially oriented polypropylene film (BOPP) is a kind of transparent flexible packaging material developed in 1960s. It uses a dedicated production line to mix polypropylene raw materials with functional additives, melt and mix them to make sheets, and then stretch them to make films. Bopp film not only has the advantages of low density, good corrosion resistance and heat resistance of PP resin, but also has good optical properties, high mechanical strength and abundant raw materials. In addition, it can also be used to prepare electrical membrane, microporous membrane and other high value-added functional products, so the development prospects of BOPP film are very broad. Up to 2004, the production capacity of China's BOPP film production line was 1.9 million tons, the actual output was about 1.76 million tons. The use of Low-density polyethylene film (LDPE) Low-density polyethylene is under high pressure, free radical polymerization of ethylene to obtain a synthetic resin, it is also known as "high pressure polyethylene. ". LPDE is a branched molecule with different branched chains in the main chain, and each 1000 carbon atoms in the main chain has about 15 ~ 30 branched chains of ethyl, butyl or longer. Because there are more long and short branched chains in the molecular chain, therefore, the product has low density, soft, low temperature resistance, good impact resistance, good chemical stability, acid (in addition to strong oxidizing acid) , Alkali Resistance, salt corrosion, with good electrical insulation. Low-density polyethylene also has a wide range of applications, such as packaging. There are many kinds of polyethylene packaging film, and its properties are different. The single-layer film has single properties and the composite film has complementary properties, so it becomes the main material of food packaging. Secondly, polyethylene film is also used in civil engineering, such as Geomembrane. It can play a waterproof role in civil engineering, and has very low permeability. Agriculture is the application of agricultural film, can be divided into plastic film, plastic film, bitter covered film, Green Film, etc. . The use of polyester film (PET) polyester film (PET) commonly known as polyethylene terephthalate, is a thermoplastic engineering plastics. The thick sheet is made by extrusion method and then the thin film material is made by biaxial tension. Polyester film is characterized by excellent mechanical properties, high rigidity, hardness and toughness, puncture resistance, friction resistance, high and low temperature resistance, chemical resistance, oil resistance, air tightness and fragrance retention, it is one of the most commonly used composite film substrates, but its corona resistance is not good. The price of polyester film is higher, the thickness is generally 0.12 mm, commonly used as the outer layer of food packaging materials, printing is better. Due to the complexity of polyester film and difficult to judge, customs supervision has brought certain difficulties. The chemical name of Nylon for plastic film use is polyamide (PA) . There are many kinds of nylon for industrial production at present, among which the main varieties for film production are Nylon 6, Nylon 12, Nylon 66 and so on. Nylon film is a very tough film, good transparency, and has a good gloss, tensile strength, tensile strength, but also has good heat resistance, cold resistance, oil resistance and resistance to organic solvents, wear Resistance, puncture resistance is good, and relatively soft, oxygen resistance is good, but the water vapor barrier is poor, moisture absorption, moisture permeability, heat sealing is poor, suitable for packing hard goods, for example, greasy food, meat products, fried food, vacuum packaging food, cooking food, etc. . Casting polypropylene film (CPP) is a kind of non-oriented flat-extruded film produced by melt casting and quenching. It is characterized by high production speed, high yield, film transparency, gloss, thickness uniformity, excellent balance of performance. As a result of flat extrusion film, follow-up work such as printing, laminating is very convenient, widely used in textiles, flowers, food, daily necessities packaging. The use of plastic film aluminum coating has both the characteristics of plastic film and the characteristics of metal. The function of aluminum plating on the surface of the film is to block light and prevent ultraviolet radiation. It not only prolongs the shelf life of the content, but also improves the brightness of the film. Therefore, the aluminum coating is widely used in composite packaging, mainly used in biscuits and other dry, expanded food packaging, as well as some medicine, cosmetic packaging.
