Plastic films have a wide variety of properties and are widely used, and their uses vary in terms of their properties. So do you know the types and uses of plastic films? In this article, I will introduce you some common plastic film basic characteristics and applications. Let’s take a look.
Polyethylene (PE) film
PE film is a large plastic packaging film, accounting for more than 40% of the total consumption of plastic films. Although it is not very ideal in appearance, strength, and other aspects, but it has good toughness, moisture resistance, and heat-sealing performance, and it is convenient to process and shape, with cheap price, so it is widely used.
Polypropylene (PP) film
PP film is divided into non-stretching film and biaxial oriented film. The two films have a great difference in performance, so they should be considered as different films.
Polyvinyl chloride (PVC) film
PVC film is divided into flexible film and hard film. The flexible PVC film has good elongation, abrasion resistance, and cold resistance, is easy to print and heat sealing, and can be made into transparent film. The flexible PVC film cannot be used in food packaging because of the peculiar smell of plasticizer and plasticizer migration. However, it can be used for packaging food if it’s produced by internal plasticization. Generally speaking, PVC flexible film is mainly used for industrial products and non-food packaging.
Hard PVC film, commonly known as PVC cellophane, with the advantages of high transparency, stiffness, good toughness, stable kink, good air tightness, fragrance protectiveness, great moisture resistance, and excellent printing performance, and it can be used for preparing a non-toxic film. It is mainly used for twist packing of candy, packaging of textiles and clothing, and over wrapping film of cigarette and food packaging box. However, it has poor cold resistance and is brittle at low temperature, so it is not suitable to be packaging material for frozen food.
Polystyrene (PS) film
PS film has high transparency and glossiness, beautiful appearance, good printing performance, low water absorption, and high permeability to gas and water vapor. Non-stretching polystyrene films are hard and brittle and rarely used as flexible packaging materials for their low extensibility, tensile strength, and impact resistance strength. Biaxial oriented polystyrene (BOPS) films and heat-absorbing films are primarily used in packaging.
The physical and mechanical properties, especially elongation, impact resistance strength, toughness and the like of the BOPS film prepared by biaxial stretching are obviously improved, and the original transparency and gloss are still maintained. The good permeability of BOPS film makes it very suitable for packaging fresh foods such as fruits, vegetables, meat and fish as well as flowers.
Polyester (PET) film
PET film is a kind of good packaging film. It has the advantages of good transparency and gloss, good air tightness and fragrance protectiveness, moderate moisture resistance, and reduced moisture permeability at low temperature. It has excellent mechanical properties, and its toughness is better than that of all thermoplastics, with higher tensile strength and impact strength than those of common films. Also good stiffness and stable size, and is suitable for secondary processing such as printing, paper bags and the like. PET film also has excellent heat resistance, cold resistance, and good chemical resistance and oil resistance. However, it is not resistant to strong alkali, easy to carry static electricity, and no proper anti-static method. Therefore, attention shall be paid when packaging powdery articles. Its heat-sealing is so difficult that the current price is high, so it is seldom used in single mode. Most of them are compounded with PE or PP film with good heat-sealing property or coated with polyvinylidene chloride.
Polycarbonate (PC) film
PC film is odorless and non-toxic, with the transparency and gloss similar to cellophane, and the strength is equivalent to that of PET film and BONY film, especially the impact resistance strength is very outstanding. PC film has excellent properties of fragrance protectiveness, good air-tightness, and moisture- resistance, and good ultraviolet transmission resistance. It has good oil resistance, good heat resistance and cold resistance; can be steamed sterilization under high temperature and high pressure, with better low temperature resistance and freeze-resistance than that of PET films, but its heat-sealing is poor.
