Plastic packaging film materials

Introduction

Plastic packaging and plastic packaging products in the market share is growing, especially in composite plastic flexible packaging, has been widely used in food, medicine, chemical industry, among which the largest proportion of food packaging, beverage packaging such as , frozen food packaging, food packaging, cooking, fast food packaging, these products gave people life has brought great convenience.
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Several common film

Biaxially oriented polypropylene film (BOPP)
BOPP film is formed by the co-extruded polypropylene sheet by particles, and then by vertical and horizontal stretching in both directions obtained. As the stretching molecular orientation, so this film's physical stability, mechanical strength, good air tightness, high transparency and gloss, tough wear-resistant, is the most widely used print film, general use of a thickness of 20 ~ 40 μ m, the most widely used for the 20 μ m. Biaxially oriented polypropylene film sealing the main drawback is poor, it is generally used as the outer layer of thin-film composite membrane, such as polyethylene film composite with moisture resistance, transparency, strength, stiffness and printability than ideal for dress dry food. Because the surface of biaxially oriented polypropylene film non-polar, high crystallinity, surface free energy is low, so its performance is poor printing, ink and adhesive for adhesion is poor, in the printing and composite surface is needed before deal with.
Low-density polyethylene film (LDPE)
Low-density polyethylene film commonly used blow molding and casting made of two processes. Cast polyethylene film of uniform thickness, but because of higher prices, now rarely used. Blow by blow molding grade polyethylene film by PE particles blown from the blow molding machine, low cost, so the most widely used. Low-density polyethylene film is a translucent, shiny, softer texture of the film, with excellent chemical stability, heat sealing, water resistance and moisture resistance, freezing, can be boiled. Its main drawback is poor oxygen barrier, commonly used in flexible packaging materials, the inner membrane, and is currently the most widely used, the maximum amount of a plastic packaging film, plastic packaging film about the consumption of more than 40%.
As the polyethylene molecules contain polar groups, and high crystallinity, surface free energy is low, therefore, poor performance of the film print, ink and adhesives for the adhesion is poor, so the compound is required before printing and surface treatment.
Polyester film (PET)
Polyester film is polyethylene terephthalate as raw material out of the legal system into thick slices, and then biaxially oriented film made of material. It is a colorless, transparent, glossy film, excellent mechanical properties, rigidity, hardness and toughness, puncture resistance, abrasion, high temperature and low temperature resistance, chemical resistance, oil resistance, air tightness and fragrance preservation good, is commonly used composite barrier film substrate of one. However, the higher the price of polyester film, the general thickness of 12mm, the outer layer used to do cooking and packaging materials, printing is better.
Nylon membrane (PA)
Nylon film is a very tough film, good transparency, and good gloss, tensile strength, high tensile strength, also has good heat resistance, cold resistance, oil resistance and organic solvent, abrasion resistance, puncture resistance and excellent, and relatively soft, excellent oxygen resistance, but poor water vapor barrier, moisture absorption, water vapor permeability greater, poor sealing, suitable for rigid packaging materials such as oily foods, meat, fried foods, vacuum-packed food, cooking food.
Cast polypropylene film (CPP)
Cast polypropylene film is the use of cast polypropylene film production process, can be divided into regular CPP and CPP cooking class two, excellent transparency, thickness, uniformity and performance of vertical and horizontal, generally used in composite films layer of material. Normal CPP film thickness is generally between 25 ~ 50μm, with better transparency OPP composite, the surface brightness, feel strong, general gift bags are used such materials. This film also has good heat sealing. Cooking class CPP film thickness is generally between 60 ~ 80 μ m, the ability of 121 ℃, 30 min of high-temperature cooking, oil resistance, good air tightness and high seal strength, inner packaging meat in general are CPP film using cooking class.
Aluminum film
Currently the most widely used are polyester film metallized aluminum (VMPET) and CPP metallized (VMCPP). Metallized plastic film characteristics of both, but also has the characteristics of the metal. The role of aluminum film surface shading, anti-ultraviolet radiation, both to extend the shelf life of contents, but also improves the brightness of the film, to some extent replaced the aluminum foil, also has a cheap, beautiful and good barrier properties Therefore, aluminized composite package applications in a wide range, currently used in biscuits and other dry, puffed food packaging as well as some pharmaceuticals, cosmetics packaging.