There are many types of film on the market, but the most commonly used printing films are BOPP, NY, PET, and PE. As far as printing is concerned, the most important thing is, of course, the surface treatment effect of the film and whether the NY film is damp. When printing, a process requirement should be established to measure the surface tension of each film roll. The corona effect has timeliness, and if left for too long, the corona effect may decrease too much to meet the printing requirements; It can also avoid potential malfunctions caused by accidentally reversing the printing on the film surface.
PE film is the object that we need to focus on: there may be film rolls that have missed corona treatment during film blowing; Insufficient corona effect caused by excessive or uneven film thickness; Blowing film is caused by adding too much smoothing agent or a large proportion of high smoothing particles, resulting in a significant decrease in the corona effect. When the corona effect on both sides of the 12-15um PET film is not significantly different, it is easy to cause printing film roll back adhesion failure. Corona requirements for printing film: BOPP, PE ≥ 38 dynes, PET ≥ 50 dynes, NY ≥ 52 dynes. After the NY film absorbs water, it will not have a significant impact on the corona effect. To determine whether the NY film absorbs water, check if there is any shrinkage or tendency of the film. Cut a film and put it in the oven for a few hours to check if it feels hard. If there is a tendency or hardening, it indicates that the NY film has absorbed too much water. When purchasing thin films, it is necessary to explain the purpose and requirements of the film to the supplier. The variety of film should be refined. Just mention the names of PET, NY, and BOPP, and the supplier may have several varieties, but not all of them are suitable.