Logogroup's factories specialize in the manufacture of plastic packaging of varying complexity, of barrier materials of various types. These include lines for the manufacture of polyethylene sleeves, polypropylene film and films of combined materials - polypropylene / polyethylene / polyethylene terephthalate / foil / paper.
Basic packaging manufacturing technology has not changed for many years, improving only in detail. One of the areas of development is the improvement of the polymer resin components themselves. This includes a number of additives and additives to change and adjust the properties of the packaging.
The most common method of manufacturing plastic packaging, for example, from polyethylene is called film extrusion or "tubular film process". The manufacturing process may vary depending on a number of nuances, such as original or secondary raw material, type of polyethylene blow molding density or film structure, but the overall essence is one and the whole process consists of preparing the mixture, blowing, cooling, drawing and cutting / soldering the finished packages.
The initial stage (1) in the production of plastic sleeves is the preparation of raw materials. Polyethylene comes into production in a granular form called a resin. Raw plastic granules HDPE, LDPE or LLPDE are mixed (2) in the hopper with additional components, for example:
Anti-block component - prevents blocking (sticking) during the drying stage;
component Slip - helps ready plastic bag to open more easily and allows sliding of surfaces;
UV inhibitor (UVI) protects plastic from UV radiation, which can weaken the strength of plastic under certain conditions.
The full list of components used by the company, as well as the technological blend maps, cannot be shared. However, a general description of the process and its understanding are important for collaboration.
A unique blend is prepared for each individual order, depending on the required packaging characteristics. This causes considerable minimum order volumes and the inability to produce products in small batches.
Prepared resin is fed into extruders - special pumps for thick liquids (3). There the material is heated to the desired temperature and stirred. The resin heating temperature depends on a number of parameters and can fluctuate near the 260 ° C mark. The material in the heated container, having reached the molten plastic state, is blown through the die into the form of a sleeve (4). The shape of the stamp adjusts the size and thickness of the sleeve and the future package. After passing the Frostline point (5), the molten polyethylene solidifies into the film (6).
The final step of the extrusion process is to guide the sleeve through a series of rollers at the top of the cooling tower (nip rolls) and insert a flat film, which is then wound into rolls (7-8). The heights of the extrusion tower can range from 7 to 10 meters. This is the height required for sufficient cooling of the plastic film. Further, if necessary, the film is treated with an electrostatic current wave. This is part of the film-to-print (activation) procedure.
Prepared sleeves fall into flexo machines - rotary machines for printing on flexible surfaces.
A unique cliché is made for each order. This is another reason for large product runs.
Note that color components are used as the base color for the plastic film (package). Adding coloring components occurs at the initial stage, before extrusion.
When the printing process is complete, the film rolls are cut to the desired size. Slicing and perforation may occur during cutting. For the production of products directly (packages), the film-semi-finished product is fed into machines (automatic machines) with specialized equipment, which forms the characteristic features of each product: side and bottom folds, zip-locks, valves, seals, ventilation valves, ventilation openings, reinforced seams, etc.
When it comes to finished products, not semi-finished rolls, it is important to understand that each type of packaging has the characteristic design features that change the package functionally. Follow our blogs in soc. networks and on this site where we will go into more detail about each type of package design and how to choose the right package.
The process of film extrusion to create plastic bags has not changed for many years. What has changed is how we use plastic bags in our daily lives - once a novelty is now an everyday convenience that makes our lives better.