Pearl film is made from polypropylene resin as raw material. Then add calcium carbonate and pearlescent pigments and mix them. Finally, pearl film is finished by biaxial stretch. Because of applying mechanical foaming method, the proportion of pearl film is just 0.7, while that of PP is about 0.9. Thus flexible packaging companies are willing to use pear films for their inexpensive prices, good decoration, and excellent performance. Generally, because they have a certain pearl effect, BOPP pearl film/CPP of composite structures and BOPP Pearl film/PE are often used in cold drink packaging such as: ice cream, heat seal label, sweet food, biscuits, and local flavour snack packaging.
Pearl Film Theory
Pearl film is a kind of BOPP film produced by adding pearl pigments into plastic particles and through biaxial stretch heat setting. A typical pearl film is BOPP pearl film produced by A/B/A3 layer co-extruded biaxial stretch. Among them, B is polypropylene mixed with pearl master batch, and A is a kind of PP copolymer varies depending on the properties of pearl film surface, with good heat sealability. Biaxial stretch is done below the melting point of B but above the melting point of A.
Because B contains much pearlescent inorganic pigment particles, the biaxial stretch result will be that polypropylene molecules orient along with the exogenous process direction, and the distance between the pearlescent pigment particles is widened, forming holes, making B layer foam plastic for mechanical foaming. Therefore, pearl film of A/B/A structure is a kind of two-way stretch foam plastic film, proportion of which is less than that of BOPP film, only 0.7~0.75, and generally the average proportion of BOPP film is about 0.9.
A layer protects B layer in the BOPP pearl film and gives pearl film certain heat sealability. So pearl film of A/B/A structure has good heat sealing property. However, pearl film only made from B material can only rely on the porocity of film and some heat sealing property of small amounts non-oriented PP molecules. So the heat seal pearl film is easy to peel.
Application of Pearl Film in Auto Industry
In recent two years, there is a kind of gorgeous color alteration film appeared in car body colour alteration film industry, which we call pearl film.
Take car clothes as an example, the pearl film imported from Belgium include black, pink, white, orange, purple, red, blue and apple green. After the pearl film is stuck on the car body, under lamp light or sunlight, it will give out gorgeous colors, very ornamental. Many car owners who like pursue individuality and rate of second glance will choose pearl film.
Bopp-film.net provides more than 20 years of BOPP plastic film production, providing its customer the most advanced range of BOPP products in the WORLD today.
BOPP Film Manufacturer 