1. Biaxially oriented polypropylene film (BOPP) The biaxially oriented polypropylene film is obtained by coextruding polypropylene particles into a sheet and then stretching in both directions. Due to the orientation of the stretched molecules, the film has good physical stability, mechanical strength, air tightness, high transparency and gloss, and is tough and wear resistant. It is the most widely used printing film. Generally, the thickness is 20-40 μm, and the most widely used is 20 μm. The main disadvantage is that the heat sealability is poor, so it is generally used as the outer film of the composite film. For example, it is ideal for moisture-proof, transparency, strength, stiffness and printability after being combined with a polyethylene film, and is suitable for containing dry food. Since the surface of the biaxially oriented polypropylene film is non-polar, the crystallinity is high, and the surface free energy is low, the printing performance is poor, the adhesion to the ink and the adhesive is poor, and the surface is required before printing and compounding. deal with. 2. Low density polyethylene film (LDPE) The polyester film is a film material made of polyethylene terephthalate as a raw material, formed into a thick sheet by extrusion, and then biaxially stretched. 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, but the price of polyester film is relatively high, generally 12 μm thick, commonly used as the outer layer material of retort packaging, and the printing suitability is better. 3. Nylon film (PA) 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 wear 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, mostly used Packaging for greasy foods, meat products, fried foods, vacuum-packed foods, and cooked foods. 4. Cast polypropylene film (CPP) The cast polypropylene film is a polypropylene film produced by a casting process, and can be divided into two types: ordinary CPP and cooking grade CPP. The transparency is excellent, the thickness is uniform, and the longitudinal and lateral properties are uniform, and generally used as a composite film. Layer material. 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. At the same time, the film also has good heat sealability. The cooking grade CPP film is generally between 60 and 80 μm thick. It can withstand high temperature cooking at 121 ° C for 30 minutes. It has good oil resistance and air tightness and high heat sealing strength. The inner layer of general meat packaging is good. A cooking grade CPP film is used. Shaoxing Grace International Trade Co.,Ltd , https://www.shaoxinggrace.com
2. Polyester film (PET)
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