What is the white point on the protective film?
There are many white spots on the protective film, some of which are caused by the production process, others are caused by improper storage after production, and the white spots appear to cause great losses to the product itself. Therefore, how to eliminate these white spots? It is the knowledge that both manufacturers and manufacturers need to have.
So how to reduce the impact of protective film white spots on the product? The following points can be noted:
1. Different batches of inks increase the particle size detection index and are strictly controlled. In particular, the particle size and particle size distribution of full-bottom inks are not used outside the standard range; choose an excellent and stable supplier, such as Hua Li Bao Co., Ltd. email@example.com
2, using electronic protective film adhesive. The special adhesive for the electronic protective film composite has a lower surface tension and the coating and spreading effect on the surface of the glue layer is obviously better than that of the general-purpose adhesive. The use of glue glue will be very easy to control the leveling of the glue, and has a better coating state. From the adhesive coating state alone, the use of electronic glue can eliminate the possibility of white point phenomenon.
3. The viscosity of the glue has a certain matching relationship with the number of roller lines of the network. Exceeding the matching range too much will destroy the coating state of the glue, resulting in more attention to the production of “white spots”.
4, using electronic protective film coating method. The commonly used coating process is the printing film (ink surface) gluing. Here a special coating method is used to avoid the problem of uneven infiltration of the ink layer by the ethyl ester, and to avoid the problem of inhomogeneity of the ethyl ester to the ink layer. At the same time, the coated adhesive can fully and evenly cover the surface of the adhesive layer, so that white spots can be well eliminated. But this kind of craft has its very big limitation, first of all, is only limited to compound of VMPET, and other electronic protective film is influenced by the heat in the oven under the action of tension, will be stretched and deformed; Second, will sacrifice a certain peel strength .
5, flexible packaging companies must adhere to the regular cleaning system of the coating roller, to master the correct coating roller cleaning method. In the production of full-bottom or light-colored printing films, two points should be noted. First, the scraper, coating roll, spreading roll, etc. should be thoroughly cleaned before production.
6, should be completely dry adhesive. Due to the better barrier property of aluminum plating, if the bonding in the composite film is not completely dry, then after the composite film enters the curing chamber, a large amount of residual solvent needs to be released quickly. Under the barrier of the electronic protection film, a bubble is bound to form. . Even if there is no white point when leaving the machine, white spots will appear after aging.