FREQUENTLY ASKED QUESTIONS
Self-adhesive membranes are divided into monomeric, polymeric and cast. Monomeric is the simplest form of material with the smalest durability and the least properties. Polymeric, contains additional additives that give them more durability and more elasticity.
Both of these categories are produced in the same way, that is, by pressing an almost solid mixture between a series of cylinders until it acquires the desired thickness. The cast membranes, unlike the previous two, come from a liquid mixture that is poured (hence the name) from a spout, leaving it to dry in silence. In this way, the phenomenon of memory and shrinkage of polymeric and even more so of monomeric membranes is not observed.
Cast membranes, due to the way they are produced and their composition, are the top solution in durability and elasticity for long-term applications even on surfaces with strong curves.
Lamination is not always necessary. There are cases that can be avoided, for example in indoor applications, in a short time and in latex and UV prints where these inks have a high scratch resistance.
The type of lamination must follow the type of material. That is, monomeric lamination for monomeric material, polymeric for polymeric and cast for cast. Regarding the texture, ie glossy or matte, the choice is mainly subjective, although there are some features that can guide us.
For example, matte lamination prevents unwanted reflections, “forgives” application imperfections and printing failures, but slightly “sheds” the intensity of the colors. The glossy on the other hand, enhances the colors but any imperfection may be visible.
Finally, for a perforated adhesive film (one-way vision), there is a special polyester or cast lamination of high transparency in order to gain the highest visibility from inside out.
Digital printing inks are divided into Latex, UV and Solvent / Eco solvent. Today, all inks have a certificate for harmful emissions and indoor use, but not all certificates have the same weight.
Thus, Latex inks are recommended for full coverage of a space, UV and Eco solvent for a smaller area, while Mild solvent for small poster-sized prints.
Each type of ink dries differently, thus affecting the production times when it follows another stage besides printing (lamination, perimeter cutting, die cutting). Latex inks dry at high temperatures, evaporating the water that is their main ingredient. UVs are polymerized by exposure to ultraviolet radiation which causes a photochemical reaction and dries.
Finally, Solvent / Eco solvent must completely remove the solvents they contain and for this reason the print must remain exposed to air and temperature, often up to 48 hours. Therefore, the inks that allow us to process the material immediately after printing are Latex & UV, unlike solvent which, if not dried properly, risks damaging the glue and plating the material by trapping the solvent that is trying to evaporate.
Many times, when a print on a self-adhesive film is large, water or a mixture of water with neutral soap is used to prevent air bubbles during application. However, there are cases where the use of water is prohibited. 1. When the adhesive of the membrane is not based on solvent but on water, and this happens mainly on very cheap media. The result is that the glue weakens and there is a risk that the material will come off. 2. In a plasticized self-adhesive perforated film (one way), because the water will be trapped in the holes of the material, significantly complicating vision and creating a risk if exposed to high temperature, to dilate and detach the membrane. 3. In a film with technology glue that facilitates the escape of air preventing the creation of air bubbles, also known as Easy Apply, Bubble Free, Rapid Air, Comply, etc. 4. Finally, in the application of a membrane on polycarbonate material, as this has the property to absorb moisture and when exposed to temperature it violently eliminates it by displacing and detaching the membrane.
The laminator, in addition to the overlamination of the printed film, can be used for the lamination on rigid materials e.g. antigraffiti, for lamination of prints on sheet materials e.g. Foamboards, ACP etc and finally for the application of transfer tape in graphics that have a long length but also in painted or sensitive materials such as protection film.
The space in which a printer operates must have a temperature close to 20 degrees, humidity 65% and be clean without dust, material spills and other contaminants, gaseous, liquid, or solid.
Self-adhesive films, among other things, are separated according to the type of their adhesive. So, the most common categories are permanent and removable. The first, as its name suggests, is intended for permanent applications. Its strength usually ranges from 16-18N / 25mm and sometimes, it is available with technology that facilitates air escape, preventing the formation of air bubbles, also known as Easy Apply, Bubble Free, Rapid Air, Comply, etc. as well as repositioning & repositionable adhesives.
This category also includes high-strength adhesives (High Tack, Super Tack, etc.) intended for applications on uneven surfaces or surfaces with low adhesion and the strength of the adhesive often exceeds 28N / 25mm. The second category, the removable glue is usually used in short or medium duration applications where easy detachment and avoidance of glue residues is required. Such applications are, for example, surface coatings with advertising messages of a certain duration, eg metro, buses, shop windows, etc. as well as interior decoration that ideally after removal will not need to be repaired wall.
HOP means High Opacity and is the latest innovation from Avery Dennison, which has managed to merge two categories of materials, the sticker with the white back (transparent glue) and the opaque (gray glue) making a material with a white back so as not to disturb when visible from the back and at the same time with 99% impermeability to light to completely cover the applied surface. The result is to provide a material for all applications, thus reducing the need for the professional stock to hold two materials.