Manufacture of polypropylene bags: technology and equipment

As the processes of industrial manufacturing of goods are optimized, the approaches to their technical organization also change. The use of compact machines makes it possible to use small premises, which also affects the cost of production. The tendency to rationalization while ensuring the process of manufacturing products is particularly noticeable in areas serving household needs. So, the production of polypropylene bags is oriented to a wide audience of consumers, among which, however, not only ordinary buyers, but also large enterprises. This causes interest in the segment from small entrepreneurs who decide to open their own production lines.

What is a polypropylene bag?

This is a kind of packaging bags, the purpose of which can be considered as universal. Nevertheless, the main field of application of such products is reduced to domestic use - as a rule, they contain bulk materials, dry mixes, fodder fillers, etc. A polypropylene bag is also used to store non-food items. Even the construction industry widely uses such packaging for storing and transporting cement, coal, various mixtures and garbage.

Depending on what manufacturing technology is used by the enterprise, the product is endowed with certain characteristics. For example, the production of polypropylene bags in Russia has recently been actively mastered by the technology of conductive fabrics. Thanks to the innovation the range is replenished with electrically conductive and antistatic bags. As for the primary characteristic in the form of the ability to cope with loads, the standard polypropylene is oriented to a mass of 5-10 kg. Specialized big bags are able to withstand 50 kg or more, but such products are usually produced on individual orders.

Technological stages of production

The process begins with the preparation of raw materials, from which the basis for the formation of bags is subsequently produced. First of all, the plastic filler from granules is mixed and dried. For the sake of economy, it is also permissible to produce polypropylene bags of recyclables that can be mixed with a clean substrate, after which the mixture is dyed and diluted with modifying additives.

The next step is to feed the prepared mass to the extruder, where it is heated to 260 ° C. The result of this stage is the process of forming flat filaments. Cutting and cooling methods allow technologists to form optimal flat fibers for the interlacing of future bags.

The fabric base is created on circular looms, which release the sleeve by winding the woven fibers onto special reels. The final stage is the cutting of the finished fabric base to the specified dimensions and the stitching of the material into the finished product. This is the classic production of polypropylene bags. Technology and equipment can also provide for certain features of the process, as required by the customer. For example, as an additional step, flexography can be introduced.

Flat Thread Extrusion Line

The direct production of the material from which the polypropylene bag will be made begins with an extrusion process. To begin with, the appropriate mixture must be prepared, which is also developed taking into account the required performance of the final product. The basis of the line is an extruder that produces plastic film. Most models work with a wide range of polymer bases, but in any case, the main operations include heating, extrusion and stretching. If production of large-size polypropylene bags is envisaged, the extruder is initially tuned for feeding broad dense fibers. However, the subsequent steps allow you to adjust the film to the desired format.

Round loom machines

To form the fabric base, circular loom aggregates are used. With their help, the creation of continuous sleeves made of polypropylene. There are several modifications of such equipment, which differ in the number of shuttles. So, among the basic versions it is possible to mark a 4-shuttle machine. The advantages of this unit include the minimum amount of wear-prone parts, so that it benefits from analogues in durability. This also increases the overall reliability of the line on which polypropylene bags are manufactured.

The equipment is supplied with a transfer system with roller wheels, which do not need constant lubrication. This nuance, in turn, determines the ease of maintenance.

Machines for cutting and sewing bags

Cutting can be done mechanically and manually. On an industrial scale, the first option is often used. In this case, they use aggregates that automatically cut bags from prepared hoses at an average speed of 40-50 pieces. The maximum width of the rolls available for machining reaches 800 mm in standard formats. In some cases, manual production of polypropylene bags justifies itself.

The cutting technology of this type provides for the use of special tables, on which the operators serve, in addition, sleeves of non-standard sizes. After this, the equipment for sewing sliced bases for sacks comes into play. Typically, such aggregates form a seam along the upper and lower layers of plastic tissue.

Flexographic printing machines

Printing is performed by special machines provided with photosensitive matrices. The most common flexible machine provides the ability to print on plastic fabric made of polyethylene and polypropylene. Some lines also use offset aggregates, which are distinguished by their ability to apply two- and three-color printing. These are modern high-precision devices, which are controlled through electronic panels. In particular, the production of polypropylene bags (pictured below) provides for the use of flexographic equipment of this type.

Requirements for production conditions

Regardless of the composition of the work line, the owner of the production must ensure the proper operating conditions of the equipment. First of all, like all workshops whose operation is related to the processing of polymers, such lines must be removed from residential buildings. In the same premises, it is necessary to provide an efficient ventilation system, to carry out communications in the form of sewage and water pipelines, and also to take care of installing cleaning filters.

With regard to the size of the room, the production of polypropylene bags is usually performed on processing lines with an area of not less than 50 m2. Accordingly, for optimal maintenance of such a complex, the size of the working area should be at least 80 m2.

Conclusion

The process of manufacturing polypropylene bags requires considerable investments in the organization. Renting a room and purchasing equipment are just basic expenses, but in the future it may be necessary to create additional technological steps for the company.

For example, competitive production of polypropylene bags in modern conditions is possible only with careful monitoring of product quality. Therefore, it will be necessary to equip and a point for examination of the products. It will also be necessary to organize the storage of goods. Although polypropylene bags do not take up much space and do not require special storage conditions, their appearance can be spoiled by mechanical influences during transportation - this also should not be forgotten.