In the actual production process of Pearlescent BOPP film , the CaCO3 ofparticles are uniformly dispersed in the homopolymer PP. When the PP is stretched, many holes are formed. It is these holes that refract the light to form the pearlescent effect. BOPP pearl film silver white iridescent, can reflect more light, the air resistance and water resistance than other varieties of fine BOPP films.
Application of BOPP film
The double sided heat sealing pearlescent film BOPP with a thickness of 35 m can be directly used for ice cream, ice cream and other cold drinks packaging, and can also be used for candy pillow packaging, chocolate and toilet soap packaging. Double sided heat sealing BOPP pearlescent film with a thickness of 30 m is widely used in biscuits, sweets, sweets, snacks and other packaging.
The principle of BOPP pearlescent film
Pearlescent film is a kind of biaxially oriented heat setting BOPP film which is produced by mixing pearlescent pigment into plastic particles. A typical pearl film is BOPP pearl film produced by A/B/A3 layer extruding method, where B is the mixing of the pearlescent masterbatch PP, A PP is a copolymer with pearl film surface properties vary, with good heat sealing. Biaxial stretching is performed below the melting point of the B material and above the melting point of the A material.
The Pearl contains more inorganic pigment particles B material, biaxial tensile results: Polypropylene molecules were oriented along the direction of the external force, and between the pearlescent pigment particle distance is widening, the formation of pores, the B layer into mechanical foam. Therefore, the A/B/A structure of the Pearl film is a biaxially oriented BOPP foam film, the specific gravity is smaller than the general BOPP film, only 0.7 ~ 0.75, while the general BOPP film weight is about 0.9.
The A layer has the function of protecting the B layer in the BOPP pearlescent film, and endows the pearlite film with a certain heat sealing property. Therefore, the A/B/A structure of the pearlite film has good heat sealing property. Using only B material to produce pearlescent film, porous film and can only rely on small amount without PP molecular orientation slightly heat sealing, pearl film heat sealed is easy to peel.
Performance parameters of pearlescent BOPP films item Unit Testing method Index range Thickness μm GB/T 6672 22um-120um density g/cm3 GB/T 6343 22um-50um ≤0.70 70um-120um ≤0.62 tensile strength MD MPa GB/T 13022 ≥75 TD ≥140 Glossiness % GB/T 2410 ≥50 Heat sealing strength MPa ZBY28004/86 ≥1.5(35μ以下) ≥1.8(35μ-40μ) ≥2.0(40μ以上) Surface tension single side mN/m GB 12026 38 souble side 35/38 Whiteness % GB/T 2913 ≥85 corona treatment mN/m --- ≥38