Plastic packaging and plastic packaging products in the market share is growing, especially in composite plastic flexible packaging, has been widely used in food, pharmaceutical, chemical and other fields, among which the largest proportion of food packaging, such as beverages packaging, frozen food packaging, retort food packaging, snack food packaging, these products give people's lives has brought great convenience.
Several common film
1, biaxially oriented polypropylene film (BOPP)
BOPP film is formed after the co-extruded sheet of polypropylene particles were then drawn two vertical and horizontal directions and prepared. Since stretching molecular orientation, so the physical stability of such films, mechanical strength, good air tightness, high transparency and gloss, tough wear, is currently the most widely printed film, generally having a thickness of 20 ~ 40μm, the most widely used of 20μm. BOPP sealing main drawback is poor, it is generally used as the outer layer of the composite film of the film, such as polyethylene film composite after moisture resistance, transparency, strength, stiffness and printability than that ideal for containing dried food. Since the surface of biaxially oriented polypropylene film of a non-polar, high crystallinity, surface free energy is low, so its performance is poor print, ink and adhesive poor adhesion, prior to printing and composite surfaces need to be deal with.
2, low-density polyethylene film (LDPE)
LDPE blown film and cast generally use two processes is made. Cast polyethylene film thickness uniformity, but because of higher prices, is rarely used. Blow by blow molding grade polyethylene film PE particles were blown from the blow molding machine, low cost, so the most widely used. LDPE film is a translucent, shiny, soft texture of the film, has excellent chemical stability, heat sealing, water resistance and moisture resistance, freeze-resistant, can be boiled. Its main drawback is the poor oxygen barrier properties, the composite flexible packaging materials commonly used in the inner layer of the film, and is currently the most widely used, the largest amount of more than a plastic packaging film, plastic packaging film, about 40% of consumption . Since polyethylene molecules contain polar groups, and high crystallinity, surface free energy is low, therefore, poor printing performance of the film, ink and adhesive adhesion is poor, so before printing and complex needs surface treatment.
3, a polyester film (PET)
Polyester film is polyethylene terephthalate as raw material, extrusion method into thick slices, and then by two-way stretch film material. It is a colorless, transparent, glossy film, excellent mechanical properties, high stiffness, hardness and toughness, puncture resistance, abrasion resistance, high temperature and low temperature resistance, chemical resistance, oil resistance, air tightness and preserving flavor good, it is one of the barrier composite film substrate commonly used. But higher prices of polyester film, generally a thickness of 12mm, outer packaging used to do cooking materials, printing better.
4, a nylon film (PA)
Nylon film is a very tough film, good transparency and good gloss, tensile strength, high tensile strength, but also has good heat resistance, cold resistance, oil resistance and organic solvent resistance, abrasion resistance, excellent puncture resistance, and relatively soft, good oxygen barrier properties but a poor water vapor barrier properties, moisture absorption, moisture permeability is large, poor heat-sealing properties, suitable for packaging with hard objects, such as greasy food, meat, fried foods, vacuum-packed food, cooking food.
5, cast polypropylene film (CPP)
Cast polypropylene film is cast polypropylene film production process can be divided into ordinary cooking class CPP and CPP are two, excellent transparency, uniform thickness, and uniform performance vertical and horizontal direction, generally used in the composite film layer material. Common CPP? Thickness of the film is generally in the 25 ~ 50μm? Between, and after OPP composite better transparency, bright surface, feel strong, general gift bags are used such materials. This film also has good heat sealing properties. Cooking class CPP film thickness is generally between 60 ~ 80μm, the ability of 121 ℃, 30? Min of high-temperature cooking, oil resistance, good air tightness and high heat seal strength, the general inner meat packaging are used cooking class CPP film.
CPP packaging films
6, aluminum film
Currently the most widely used aluminum metallized polyester film mainly (VMPET) and CPP aluminized plating (VMCPP). Both feature aluminized plastic film, but also has the properties of the metal. The role of aluminum film surface shading, anti-ultraviolet radiation, both to extend the shelf life of the contents, but also improves the brightness of the film, instead of the aluminum foil from a certain extent, also cheap, beautiful and good barrier properties, so , aluminized composite packaging in a wide range of applications, mainly used in biscuits and other dry, puffed food packaging as well as some pharmaceuticals, cosmetics packaging.
