The state of the ink in the printed matter mainly refers to the nature of the paper, the ink properties, the thickness of the ink layer, the area of ​​the graphics, and the density of the printed graphics. Their influence on the quality of the film is mainly the influence on the adhesive strength of the printed crystal and the film.
Thickness of the ink layer When the ink layer of the printed matter is thick and the area of ​​the graphic is large, the ink changes the porous surface characteristics of the paper, and many paper fiber capillary pores are closed, impeding the penetration and diffusion of the adhesive, making the printed matter and the plastic film. Bonding is difficult, and delamination, blistering, etc. may easily occur. Therefore, during process selection, offset printing should be used to print products that will be covered because the ink layer of the offset product is thinner.
The role of ink dilute agent
Common ink diluting agents include white ink, weili oil and bright light paste. In the white ink, there are obvious silt particles, which are not tightly bound to the binder. After printing, these pigment particles will float on the surface of the paper and hinder the adhesion. Verite oil is made by rolling aluminum hydroxide and binder. Due to the light weight of aluminum hydroxide, it tends to float on the surface of the ink layer after printing. When the film is covered, a barrier layer is formed between the adhesive and the ink layer, resulting in stickiness. Can not close or blistering. The glossy pulp is made of resin, dry vegetable oil, drier, etc. The texture is delicate and the film is bright. It has similar properties to the conjugated multi-bond terpene resin as the main component of the cover film. They have a good affinity and can firmly adsorb the polypropylene film on the ink surface.
Dry oil added to the ink to add dry oil, can speed up the drying of the print, but dry oil plus heavy volume, easy to make the surface of the ink layer into a glossy and smooth low interface layer, the adhesive is difficult to wet and infiltration, affect the film's Fastness, therefore, to control the amount of dry oil.
Dusting Offset printing adopts a dusting process to avoid dirty printed crystals. The powder spray forms a layer of fine particles on the surface of the ink layer. When the film is coated, the adhesive does not adhere to the ink layer in every place, but binds with these powders to form a false-stick phenomenon, which seriously affects the quality of the film. Therefore, the product to be coated should avoid the use of dusting technology, printed matter that has been dusted, and is applied to cloths to wipe off the silty.
The nature of the ink stickiness of the printed product is due to the ink. To solve this problem, the ink must be improved in the process, and the ink is added in proportion to 10% of the stickiness agent, which is very effective for preventing stickiness. After the ink is added with the viscose, it not only prevents stickiness, does not affect the hue and color saturation of the printed product, but also makes the ink layer brighter, the dots are clearer, and it is also more convenient for post-printing processing procedures such as calendering, laminating, hot stamping. Wait. Viscosity adhesives can be used as an alternative to oily, dusty, and anti-adhesive dirty materials.
Gold and silver ink prints Gold and silver inks are formulated using metal powders and binders. The distribution and homogeneity of the metal powders in the binder are extremely poor, and the ink layers are easily separated during the drying process. These separated metal powders form a barrier between the ink layer and the adhesive layer, affecting the effective bonding of the two interfaces. After such a product is left for a period of time, wrinkling and blistering may occur. Therefore, the coating of gold and silver ink prints should be avoided.
Printing ink layer drying condition When the ink is not completely dry film, the high boiling point solvent contained in the ink can easily make the plastic film expand and elongate, and this is the main reason for the blistering and delamination of the product after the film coating. Full drying of the ink layer is the primary condition for guaranteeing the quality of the film. For products that are imprinted and eagerly coated, they can be dried in an oven.