What are the plastic film types and scope of use?

Answer:

The biaxially oriented polypropylene film is prepared by the co extrusion of polypropylene particles and then by stretching in two directions. Due to stretching of molecular orientation, physical stability, so this kind of film mechanical strength, good air tightness of transparency and gloss, high tenacity, wear-resisting, is currently the most widely used printing film, generally use the thickness of 20 ~ 40 m, the most widely used is 20 m. The main drawback is the biaxially oriented polypropylene film heat sealing is poor, so generally used as an outer film composite film, such as polyethylene film and composite moisture resistance, transparency, strength, stiffness and printability were ideal, suitable for holding dry food. Because the surface of biaxially oriented polypropylene film for nonpolar, high crystallinity and low surface free energy, therefore, the poor performance of printing, ink and adhesive adhesion, surface treatment and compound before printing.

Nylon film is a very tough film, good transparency, good gloss, tensile strength, high tensile strength, but also has good heat resistance, cold resistance, oil resistance and organic solvent resistance, wear resistance, puncture resistance and excellent, relatively soft, excellent oxygen barrier, but the water vapor barrier is poor, moisture absorption, moisture permeability is larger, the heat sealing is poor, suitable for packaging rigid items, such as greasy food, meat, fried food, vacuum packing food, cooking food etc..

Polyester film is made of poly (ethylene terephthalate), which is made of thick film by extrusion and then stretched by biaxial stretching. It is a colorless and transparent film, gloss, excellent mechanical performance, rigidity, hardness and high toughness, puncture resistance, friction resistance, high temperature resistance and low temperature resistance, chemical resistance, oil resistance, air tightness and fragrance is good, is one of the commonly used barrier composite film substrate. But the price of polyester film is higher, general thickness is 12 m, commonly used for cooking and packaging of outer material, printed better.

LDPE films are usually made of two kinds of blow molding and tape casting. Cast PE films are of uniform thickness, but are widely used because of their high cost and low cost. LDPE film is a semi transparent, glossy and soft film with excellent chemical stability, heat sealing property, water resistance and moisture resistance. It can be frozen and boiled. The main drawback is that the oxygen barrier property is poor, the inner membrane is commonly used in soft packing materials, and is currently the most widely used, one of the largest amount of plastic packaging film, accounting for more than 40% of the consumption of plastic packaging film.Due to the polar group containing polyethylene molecules, and high crystallinity, low surface free energy, therefore, the poor performance of the film printing, ink and adhesive adhesion is poor, so the surface treatment in printing and composite before.

PVA coated high barrier film is a strong barrier gas material, and thermal suture, moisture barrier strong polyolefin composite, is a multilayer structure of the film. PVA coating high barrier film, nano layered silicate modified PVA coating on polyethylene film, after printing and composite, the oxygen resistance rate is less than 2cm3/ (M2 ? 24h ? 0.1MPa). The barrier properties are superior to those of EVOH five layer coextrusion film, and the packaging cost is greatly reduced, which can not only ensure the packaging requirements for aseptic packaging all the quality, but also greatly reduces the cost of aseptic packaging of food processing enterprises, solve the technical bottleneck of the three layer coextrusion poor barrier properties of polyethylene packaging film. Can be used for packing beverage, fruit juice, milk, soy sauce, vinegar etc..