Development and application of KPET film (K film) high barrier film

With PET(polyethylene terephthalate) as the base material, single-side coated with high barrier PVDC(copolymer with vinylidene chloride as the main component) coated plastic film, and then coated layer can also be printed. It is often used for flexible packaging and printing substrates. Like this coated PVDC film, also known as K film, K film in the selection of substrate, in addition to PET, there are PP, PA, PE and other materials of film, used to improve the barrier performance of the substrate.


PVDC(chemical name polyvinylidene chloride) is a kind of plastic packaging products with better comprehensive barrier performance in today's society. It is not only different from acrylic emulsion with moisture absorption and sudden drop of temper resistance, but also different from nylon film because of the water absorption ability to reduce the moisture resistance performance, but is a kind of moisture resistance, gas resistance are excellent high barrier performance raw materials. With fire resistance, corrosion resistance, good air tightness and other characteristics, due to strong polarity, insoluble in general solvents at room temperature.

The development of PVDC industry is mainly along with the development of its application technology. The initial PVDC industry is only used for moisture-proof packaging of military products. In the mid-1950s, it was promoted to civil use, because it solved the blowing film technology with a thickness of only 12 microns and its self-adhesive. As a food cling film, it is still popular today. With the development of single-film composite, coating composite, casing film and co-extrusion film technology, the development of military products, medicine and food packaging industry is more extensive. Especially with the acceleration of modern packaging technology and the pace of modern life and a large number of development of frozen fresh-keeping packaging, microwave cooker revolution, food, medicine shelf life extension, make the application of PVDC more popular. For decades, its dominant position as a high barrier packaging material has not been shaken.


The production process of PVDC natural latex coating is different from that of PVDC epoxy resin film blowing machine and extrusion production and processing. The latex coating only includes the whole process of coating distribution and heating and drying. There is no additive in the final coating, so the coating is only 2-3μm thick, but its resistance to O2 and wet vapor is similar to that of a 25μm injection film.


As a barrier packaging products, PVDC coated film is most suitable for the production of composite packaging bags, mainly because the mechanical equipment and some physical properties of the coating film is determined by its use of coated plate, and the final resistance, fragrance, acid and basic resistance is given by the coating, Users only need to select the barrier level of plate and coating according to the characteristics of the packaging items and distribution conditions to clarify the mechanical equipment, physical performance regulations and the level of maintenance of the packaging products.