How to solve the problem of poor adhesion of laminating products in packaging printing

Packaging box printers and product manufacturers sometimes in order to improve the surface gloss effect and mechanical resistance of the box, often using laminating to the surface of the box for processing, laminating process for a variety of commodities packaging, can achieve the protection and beautification of goods, improve the role of added value of goods.

In the process of packaging printing and laminating, the most likely quality failure is that the film of the laminating product is not solidly bonded to the printed product and is easy to fall off, which will directly affect the use of post-processed laminating products and the life of the product. The formation of this printing problem is not only caused by one-sided reasons, we also need to combine the printing ink, printing process for comprehensive consideration.

First, the printing ink

In the printing process, the lamination process is relatively simple, mainly through the adhesive will be printed with the film well bonded together. In the print non-graphic area because there is no printed graphics, so the surface of the region is a porous loose structure, such a structure is conducive to the penetration and diffusion of adhesives, that is, the print graphic area of the ink is the main reason for the impact of the print and film bonding is not real.

The effect of ink on the effect of lamination is mainly the surface properties of the ink after drying on the adhesive. But when the ink dries, the main component of the surface layer is ink washout.

Of course, at the same time will also contain some other substances, for example, white ink components in the powder particles due to insufficient binding force with the linker, will float in the oil surface layer, and then dry; Veli oil components in the aluminium hydroxide due to the quality of the too light, but also will float in the ink surface layer; glossy paste components of the film-forming resins, which can improve the effect of the film-forming in the oil, but also at the surface layer of the ink.

In the lamination, the ink surface layer of white ink pigment particles will have a hindering effect on the adhesive, affecting the adhesive in the print ink layer surface of the further penetration; Veli oil in the aluminium hydroxide is prone to the formation of an isolation layer, impede the interaction between the adhesive and the ink layer, resulting in blistering or bonding is not solid;

Glossy pulp is favourable to the effect of lamination, and its composition is also similar to the nature of the adhesive, good affinity. Therefore, the addition of ink flushing agent should be combined with the laminating effect of the product for comprehensive consideration.

In addition, the particle size of the ink will also affect the effect of film lamination. The particle is too large, will affect the film and the surface of the print adhesion effect, easy to bubble, and then bonding is not solid. Especially in gold and silver, due to the metal pigment particles in the ink will be separated after drying, hindering the mutual combination of ink layer and adhesive, so the use of gold and silver ink printing products are not suitable for lamination.

Second, the printing process

Printed products that need to be laminated need to be completed by printing before this process. Previously introduced, the surface properties of the ink after drying will affect the effect of lamination, and in the use of appropriate ink under the premise of printing width, ink thickness, drying effect and other factors will also cause the lamination adhesion is not real.

When we print too large (or use field printing), this will make the paper surface and adhesive contact area is reduced, exacerbated by the surface of the print and adhesive bonding effect of the decline in the quality and service life of the laminated products greatly reduced. Therefore, we should try to avoid laminating large format or field printing prints.

If the ink layer of the box printing is too thick, the hindering effect on the adhesive will be aggravated, which will directly cause delamination, and then can not be bonded. Comparing the characteristics of the ink layer obtained from various printing processes, the lower limit of the ink layer thickness of the prints of offset printing is 1-2um, so we suggest that if the box needs to be laminated, we should choose offset printing and pay attention to the control of the overprint effect of the colour printing and the final thickness of the ink layer of the prints.