Coating Defects
Conventional films are divided into two types: coated and uncoated. The reasons for ink flaking caused by film coating defects can be divided into two corresponding situations: for coated film materials, if the surface coating has poor fastness, it will result in poor ink adhesion; while for uncoated film materials, the poor bonding fastness between the surface layer and the ink often causes ink flaking.
To solve the ink flaking caused by coating defects, we can take the following measures: carry out topcoating varnish printing treatment on the surface layer to protect the surface of the ink and prevent ink flaking; re - treat the surface layer by corona treatment, and the corona dyne value of the material surface should be no less than 38mm/m. If the dyne value is lower than 36mm/m, it will directly affect the fastness of the printing ink.
Applying a primer on the surface layer or using an ink adhesion enhancer (with a mixing ratio of about 3%) can also improve the ink receptivity of the film surface layer. Some matte synthetic paper materials are not suitable for testing with 3M tape due to the characteristics of their surface coating similar to that of paper coatings.
Tension
For film materials with a corona - treated printing surface, to achieve good ink wetting, the dyne value usually needs to be above 38mm/m. If it is lower than 36mm/m, ink flaking problems are likely to occur. At the same time, the dyne value of this material will gradually fade over time, leading to printing ink flaking problems. The essence of this problem is a tension issue.
Ink Drying and Tension
During the printing process, ink drying and tension can also cause ink flaking. Specifically, it includes: the printing ink layer is too thick, resulting in incomplete drying; the energy of the UV lamp is insufficient, the lamp tube is aging, and the lamp tube reflector is aging, resulting in insufficient drying and curing of the UV lamp and an undried ink layer; the ink is over - dried, causing the material to deform and the ink layer to peel off.
Ink - Material Compatibility
The degree of compatibility between the ink and the material can also cause ink flaking to a certain extent. For example, if the molecular tension of the ink used is too high, it cannot form a uniform ink layer on the surface of the substrate material; or using an ink model that has exceeded its shelf life or inferior domestic brand inks will cause printing ink flaking.
Post time: Mar-10-2025
