The factors affecting lamination quality
In the process of book printing quality of lamination, the easiest to appear the quality problem of the lamination of products is glued rickety, easy to fall off; it will directly affect the sequence effect of product use effect and after life. To solve this problem, we need to combine considered printing ink, printing process, lamination process and so on.
About printing ink
When lamination, the white ink pigment particles in the surface of ink can hinder the adhesives and influence the adhesives on the surface of the printing ink The aluminum hydroxide in the oil is easy to form the isolation layer, blocking the interaction between the adhesives and the ink layer, causing the foaming or adhesion to be untrue; The light slurry has good effect on the coating effect, and its composition is similar to the adhesive properties. Therefore, when adding ink diluent, we should combine the laminate effect of the product for comprehensive consideration.
In addition, the particle degree of ink also affects the effect of lamination. The granule passes through big, can affect the lamination effect of the film and the printing surface, easy to appear bubbling, then the cement is not real. Especially gold and silver ink, due to the metallic pigment particles in dry ink to separate, hinder the combination of ink layer and adhesives, so using gold and silver ink printing product is not suitable for lamination.
About printing process
The book printing before laminated need to finishing by printing. After drying of the surface layer of ink performance will influence effect of lamination, and on the premise of appropriate use of ink, printing format, ink layer thickness, drying effect factors can cause laminating adhesive. If the printing format is too large (or using field printing), makes the paper surface to reduce the contact area and adhesives, intensifying declining print surface bonding effect with adhesives, the effect of the quality of the product and service life.
If the printing ink layer is too thick, the resistance to adhesive can be aggravated, which will directly cause the delamination, which can not be cemented. Comparing all kinds of printing ink layer characteristics, offset printing quality ink layer thickness, the lowest for 1 ~ 2 microns, so offset printing will better, laminating and attention should be paid to control color printing overprint effect and print the ink layer thickness.
Similarly, the undrying ink will cause lamination to expand and elongate, causing the laminating products to bubble, the film glued rickety. The key to solve this problem is to ensure that the ink completely dry before laminating, can adopt the way of auxiliary drying speed up production, but try to minimize the use of ink adjuvant.
1. The drying effect of adhesive
Adhesive to dry ink drying effect and the print surface situation is similar to impact on the quality of laminating machine, if the solvent is not dry completely, makes the film stretching, produce bubbles, then cause glued rickety.
2. The bonding effect of adhesive
The binding effect of adhesive is mainly considered in two aspects. Is the performance of adhesive laminating, requires both adhesive evenly on the surface of lamination, the effect is good, and according to the printing quality of the surface features and structure control adhesives thickness: the thickness too thin, can reduce the adhesion strength of the adhesive; Thick thickness can affect the drying rate. The second is the compound temperature, which can affect the molecular energy and molecular force of the adhesive. When the molecular force is over an hour, the adhesive force of the coated product is too small. In addition, composite temperature is too high, and can cause damage to membrane structure, general requirements composite temperature control in 70 ~ 90 ℃.
3. Effect of covering pressure
The effect of laminating pressure is influenced by two factors: compound pressure and membrane speed. Compound pressure can promote the penetration and diffusion of adhesive, and its size should be considered in combination with coated material and other process. Membrane speed is also a multi-impact parameter. Its size can affect the coating thickness and drying speed of adhesive, and it needs to be adjusted in combination with other factors.
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