Plastic film dry compound sticky edge refers to the phenomenon that the plastic film is dried, heated and dried after being coated with glue, and then rolled up after being pressed by a hot-pressed steel roll, and the rolled product is adhered together on both sides. And this kind of sticky edge failure will happen frequently. Once the sticking phenomenon occurs, both ends of the roll material and the film layer are firmly bonded. It is difficult to separate the finished film, often resulting in the finished film being pulled and deformed, broken, and turned into waste products, causing waste of resources. .
The non-squeegee type gluing system adjusts the amount of glue through the threaded rods at the two ends of the top roller. The squeegee type sizing system adjusts the amount of glue according to the squeegee and the anilox roller. The effect of the squeegee type sizing system on the amount of glue is the pressure and angle of the squeegee. The pressure is low, and the amount of glue is too much, which will cause sticky edges. In order to extend the life of the anilox roller, there is no sticky edge and the angle between the blade and the anilox roller is 35°.
The non-squeegee type sizing system does not affect the amount of glue as much as the pressure between the top roller and the anilox roller. The pressure is small and the amount of glue is large. On the contrary, the amount of glue is small. Because it adjusts the amount of glue through the threaded rods at the two ends of the rubber roller, the pressure at both ends must be the same during operation. Otherwise, the adhesive layer will be thick and thin on one side, and the thick side will be prone to sticking after being pressed by hot rollers. malfunction.
When non-scraper type gluing system is adopted, it will prevent sticky edge failures. Experienced masters will press the threaded rods at both ends of the rubber roller first, and then slowly adjust the amount of glue during operation. The most direct way to check the amount of glue on the rubber roller is to squeeze the rubber roller with the index finger and observe the thickness of the glue at the squeezed place.
The generation of sticky edges is also related to the drying temperature of the dryer. Drying system has evaporation zone, hardening zone, exclusion of odor zone, these 3 zones. The evaporation zone temperature is generally controlled at 60-70°C, and the hardening zone and the exclusion of the deodorization zone are generally controlled at 70-80°C. The temperature of the drying temperature varies with the width and thickness of the composite substrate. The width of the composite substrate becomes wider, the thickness becomes thicker, and the temperature should be increased accordingly, otherwise sticky edges will be produced. The width of the composite substrate is also related to the sticking edge failure. If the width of the printed substrate is greater than the width of the composite substrate, sticking must occur. At the same time glue will stick to the hot roller, seriously affecting product quality. The best way to solve this problem is to increase the width of the composite substrate. If a BOPP/OPP, OPP/PET composite structure is used, the solution is to compound the printed film as a "composite substrate."
In addition to the above factors will be easy to produce sticky edge failure, as well as the hardness of the roller is easy to produce sticky edge failure. After the rubber roller has been used for a long time, the surface lacks elasticity and there is a phenomenon of “hardeningâ€. After this phenomenon occurs, when the glue is applied, it is easy to have a glue liquid overflow and it is easy to produce a sticky edge. The solution is to place the rubber roll in a curing chamber at a temperature of about 50°C for 1 to 2 hours so as to restore the surface elasticity or replace the rubber roll with a new one.
The width of the pressure roller also has a certain relationship with the sticking edge failure. The role of the pressure roller is to compact the film and the coating roller so that it is uniformly coated and does not generate bubbles. The width of the pressure roller is generally narrower than the width of the film by 0.5mm. If the width is the same or is too large, the glue liquid on the rubber roller is easily pressed by the hot steel roller when the glue is applied. To solve this problem, choose a pressure roller that is narrower than the width of the film by 0.5mm.
There are many factors that produce sticky edges, which must be regulated during operation. Once a sticky edge failure occurs, it must be carefully observed and carefully summarized to prevent this failure from occurring again.