Film coating process is a kind of surface processing technology after printing, also known as post-press plastic, post-press laminating or post-press pasting film, which refers to the use of a laminating machine to cover a layer of 0.012~0.020mm thick transparent plastic film on the surface of the printed material to form a paper-plastic integrated product processing technology. Generally speaking, according to the technology used, it can be divided into two types: coating film and pre-coating film, and bright film and matte film according to the difference of film materials. As a way to protect and decorate the surface of printed matter, film mulching accounts for a large share of post-press processing. If you walk into a bookstore, you will find that most books use this way. This is because the surface of the printed matter covered with film will be smoother, brighter, dirt-resistant, water-resistant and wear-resistant, and the color of the cover of books and periodicals will be more dazzling and not easy to be damaged. the wear resistance, folding resistance, tensile resistance and moisture resistance of printed matter have been greatly strengthened, which protects the appearance of all kinds of printed matter and improves the service life. It is worth mentioning that the film coating can make up for the quality defects of printing products to a great extent, and many of the apparent defects in the printing process can be covered after coating (especially after the matte film). Therefore, the film coating technology is widely used in all kinds of packaging and decoration printing, various bookbinding forms of books, books, calendars, maps and so on, which is a very popular printing surface processing technology. The film mulching process was introduced into China in the 1980s. Because of its many advantages, it became very popular in a very short time.