How T-shirt packages with a logo are made

       T-shirt packages with a logo are hygienic packaging for products, a universal container for carrying loads and simply a very convenient thing that has changed our lives forever. To provide us with containers for packaging and carrying products, chain stores order T-shirt packages in bulk from manufacturer. Today in Ukraine, transparent oxo-biodegradable T-shirt packages with logo print or starch-based packages are especially popular. And we buy them with pleasure. It is so convenient and practical! Do you know what raw materials a T-shirt package is made from? How are packages made? How are T-shirt packages printed? It is very interesting and informative!

 

What are T-shirt packages with a logo for?

       Imagine you want to buy T-shirt packages in a supermarket, and the cashier shrugs his hands guiltily and says that they are no longer produced. And hands you a paper bag. You put groceries in it, go out into the street. And it's raining there. Your bag instantly soaks, oranges, sausages, a bottle of expensive French wine fall out of it. An awkward position? But that exactly how it will happen!

       Then you, learning from your bitter experience, buy a reusable shopping bag. And put dirty potatoes in it. And the next day, come with this string bag for bread and loose marshmallows for children. Which, by the way, lays now on the counter unpacked. Therefore, someone can cough or sneeze on it, someone can touch it with dirty hands.

       Luckily, such a fictional dystopian social catastrophe does not threaten us yet. After all, Ukraine has its own production of T-shirt packages, which make our life much easier, more comfortable and safer.

       You can order T-shirt packages with a logo by clicking on the link here.

 

How to make T-shirt bags with a logo

 

All that different T-shirt package

       Today you can order T-shirt packages with a logo made of several types of polyethylene. Depending on this, they will have different density, carrying capacity and even look differently.

       What raw materials are used for making packages? Polyethylene is made from ethylene. If start from the very beginning, then ethylene can be obtained in the process of thermocatalytic cracking of petroleum fractions, dehydrogenation of ethane or dehydration of ethyl alcohol. In industry, ethylene is obtained mainly from natural gas by method of thermal pyrolysis: first, ethylene is obtained from hydrocarbons, then polyethylene granules are made from it.

 

There are several technologies for the production of polyethylene, in which the following types of product are obtained:

  1. LDPE – high pressure polyethylene. The name itself speaks of the technological process – polyethylene is obtained by polymerizing compressed ethylene under high pressure. The radical substitution reaction occurs in the presence of organic peroxides under the influence of oxygen at high temperatures. A mixture of ethylene with catalytic additives is heated and compressed several times by a compressor. This results in polyethylene granules.LDPE film has good stretching properties and beautiful glossy sheen. Bags of this type of raw material are non-crease and elastic. They are pierce-proof, but stretch and take the shape of the content.

  2. HDPE – low pressure polyethylene or HDPE. There are several technologies for industrial production of HDPE: suspension polymerization, solution polymerization, gas-phase polymerization. All reactions take place at low pressure. The finished product can be in the form of granules or powder. Soft HDPE packaging is easily recognizable. Such polyethylene has a matte rough surface, does not shine, rustles when crumpled. It does not stretch, therefore it can be quite easily pierced with a sharp object. It is very strong and has a high carrying capacity. It is from it a T-shirt package is most often made. 

  3. MDPE – medium pressure polyethylene or MDPE. Obtained by polymerizing ethylene in solution. The finished product is granules ready for further production of T-shirt packages.

       MDPE polyethylene is a midway between HDPE and LDPE film. Characteristics of products made from this type of material will depend on the composition of raw materials.

      As you can see, the composition of the plastic package directly affects the quality of the product. Therefore, manufacturer can choose the right material individually for each client: for the needs of a supermarket, a construction hypermarket, a postal service, courier delivery, a shoe manufacturer or home textile.

 

T-shirt package loading capacity

       Loading capacity of the T-shirt package depends on the thickness of the film (measured in microns - µm). The larger the package, the stronger it should be, therefore, for its production, a denser (thicker) polyethylene is used. To make it easier for a buyer in a supermarket to choose a package for his purchases, maximum allowable weight of the cargo is usually indicated on it: 3 kg, 5 kg, 10 kg, etc.

T-shirt package loading capacity depending on film thickness:

  • 15 µm – 3 kg;
  • 20 µm – 5 kg;
  • 25 µm – 7 kg;
  • 30 µm – 10 kg;
  • 35 µm – 13 kg;
  • 40 µm – 15 kg.

 

How T-shirt packages are made

Each stage of production at the plant takes place in a separate workshop equipped with industrial equipment.

 

Extruder workshop

       Here, quality-controlled polyethylene granules together with various components (pigments, polymeric oxo-biodegradable additives to accelerate the degradation of eco-friendly packages) are loaded into extruder, where the mixture is heated to a certain temperature. Polymer becomes viscous, mixture passes through the hole, cools and takes the form of a sleeve, which is then inflated with an air jet to the desired size. Then the blank is finally cooled and reeled.

 

Extruder for the production of tubular films with side folds

Extruder for the production of HDPE tubular films

    

       If polyethylene is intended for the production of T-shirt packages with a logo, then it is additionally subjected to corona treatment. It increases hydrophilicity (increases surface wettability) and improves paint adhesion to polymer. How it works? Corona treatment changes the properties of the surface of polyethylene – it becomes more rough and porous. Moreover, the changes occur at the micro level and affect only the uppermost layer, while the properties of the film itself do not change. On the other hand, when drawing a picture and a logo, the paint “eats into” the micropores, therefore it does not wipe off during the operation of the product and does not remain on the consumer's hands.

 

Arrangement of the extruder for the production of tubular films

 Schematic of an extruder for the production of tubular films


 

Arrangement of the extruder:

  1. Pneumatic loader;
  2. Bunker for polyethylene and additives;
  3. Extruder screw;
  4. Forming head;
  5. Cooler;
  6. Ring band;
  7. Film sleeve;
  8. Folding jaws;
  9. Puller;
  10. Film canvas;
  11. Wide-centering rolls;
  12. Cutter;
  13. Reeler.

 

Flexo-printing workshop

       Here, ink is applied to the blank for the production of T-shirt package with a logo. There are several types of flexographic machines, differing from each other in the location of the ink units (vertically, horizontally, on the central shaft).

       For flexo-printing, flexo-molds are used – cliches made of the finest photosensitive photopolymer plates from which inks are transferred to polyethylene. In order for the flexo-mold to be reused for the next batch of logo T-shirt packages, it must be stored under certain conditions. Only the packaging manufacturer can provide such a temperature, humidity, light and sanitary and hygienic regime. That’s why flexo-molds are not given to the customer together with a batch of finished products.

Advantages of flexography:

  • excellent image quality and photographic accuracy;
  • multicolor;
  • low cost;
  • high speed application;
  • large selection of paints: water-based, alcohol-based, quick-drying UV inks;
  • cost-effectiveness ensured by the minimum amount of canvas waste;
  • minimum amount of rejects, since overlaps and omissions of a pattern during printing are practically excluded;
  • possibility of large format printing.

Flexography has many advantages over silk-screen printing, for example. Flexo-printing is cheaper, it allows you to apply full color images of any size.


4-color deck-type flexo-printing machine with printing on two reels simultaneously

4 color deck flexo machine  


 

Arrangement of decked-type flexographic machine:

  1. unit for unreeling unpainted bobbins;
  2. printing units;
  3. drying system;
  4. unit for reeling painted bobbins.

 

Package-making workshop

       Here the blank with the printed logo is soldered with a special knife for contact-heat welding, creating side or bottom seams. Then the sleeve or half-sleeve is cut according to the pattern and ready-made packages are obtained.

 

High speed double row package-making machine

Double row bag making machine

    

Polymer recycling workshop

       Any polymers (with the exception of biodegradable, that is, containing additives to accelerate degradation) can be recycled. The secondary granule can be made as identical as possible to the primary one, or its mechanical strength or heat resistance can be increased with the help of additives.

Technological process of recycling consists of the following stages:

  • sorting (LDPE cannot be made from HDPE and vice versa, since the molecular weight characteristics of the polymer do not change during recycling);
  • grinding;
  • cleaning;
  • drying;
  • agglomeration;
  • obtaining granules.

If a plastic compactor is used in the processing line instead of agglomeration (it, like the agglomerator, compresses polyethylene flakes), then the drying stage is excluded.

       There are other recycling technologies, such as pyrolysis. However, in this case a separate industrial pyrolysis plant is needed.

       Polyethylene is an ideal material for recycling, as a result of which old things get a second life. If we learn to collect and sort garbage, we will solve many problems of civilization.


Fun facts about plastic and plastic packaging

  1. Soft packaging protects food and extends its shelf life. As a result, the amount of CO2 emissions into the atmosphere decreases by ten folds (carbon footprint, which is now on everyone's lips, is reduced). By the way, if we count the amount of CO2 emissions per unit weight of the product, then the most significant harm to the environment is caused by the production of meat and milk, the minimum – by organic fruits and vegetables. If we count CO2 emissions per calories, then canned vegetables are the most damaging to the environment, followed by chicken eggs.

  2. Research has proved that the appearance of packaging shapes our minds about the product. For example, consumers find products in green packaging to be healthier. The amount of text also has a positive effect on the perception of the quality of goods. The more information the manufacturer has put on the package, the more useful the product, buyers believe.

  3. 1 ton of recycled plastic saves almost 6,000 kWh of electricity, 2,500 liters of gasoline, 28,700 kWh of energy or 40 cubic meters of land that would be used as landfills.

  4. Out of all human waste, only 10% is plastic. The rest of the garbage is food waste, textiles, glass, paper, construction materials, household appliances that have served their time, etc. All this is practically not recycled, but goes straight to the landfill. And it does the environment only slightly less harm than plastic. The only difference is that other types of garbage decompose much faster. However, they still have time to thoroughly litter the world's water supplies, land and air.

 

Hence, the production of soft packaging is more beneficial than harmful. It remains to address the issue with its collection and recycling.

 

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