Types of biaxially oriented polypropylene

　　Biaxially oriented polypropylene films are classified according to their uses. At present, the common types are heat sealed, pearlescent and capacitive. In addition, there are shrinkage film, extinction film, antifogging film, label film, synthetic and BOPP / PE film, BOPP / CPP composite film, vacuum aluminizing film, cooking bag composite film and barrier film.

　　The types of biaxially oriented polypropylene are as follows:

　　(1) Common biaxially oriented polypropylene film

　　The common biaxially oriented polypropylene film is made of polypropylene resin as the main raw material and some auxiliary materials. The film has the characteristics of good strength, high transparency, heat shrinkable, low moisture permeability and moderate corona treatment. Because of its good printing performance, it can be used as adhesive tape substrate and vacuum electroplating metal foil layer, so it is widely used in food, clothing, tea and milk powder packaging. The commonly used films are 20um (printing composite film), 30um (adhesive tape film) and 40um (calendar film).

　　Biaxially oriented polypropylene film for general use, according to the standard BG / T 10003-2008, can be divided into ordinary type (Class A) and heat sealing (type b) according to whether there is heat sealing layer on the surface.

　　(2) Heat sealed biaxial tensile film

　　The heat sealing biaxial tensile film is made of biaxially oriented polypropylene film coated with a thin layer of chlorinated polypropylene (PP and copp) can also be used as raw materials, and some auxiliary materials are properly added to co extrude the three-layer film. In addition to the properties of BOPP film, the film also has the characteristics of low temperature heat sealing performance, low friction coefficient and water vapor filtration. It is mostly used in the packaging of candy, food and biscuits. It can directly heat seal and keep the surface smooth.

　　(3) Capacitive biaxially oriented polypropylene film

　　It is required that the resin used for forming this kind of film has high purity and the ash content is less than 0.1 * 10 ^ - 3,. In addition to the properties of ordinary thin films, this kind of thin films should also have good dielectric strength, volume resistivity, dielectric constant, dielectric loss angle tangent and other electrical properties; the film is generally less than 20um, which is mostly used to manufacture oil immersed power capacitors and metallized film capacitors.