What is PVC film and how is it marked

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Packaging materials have become one of the main products consumed by industry in the 20th century. There is every reason to believe that their importance will only increase in this century. PVC (polyvinyl chloride) film occupies a special place among such materials.

Packaging should perform several functions. Its main purpose is to protect goods from harmful external influences, pollution, damage during transportation and during the sale process. Other factors that influence the motives of the buyer are also important, such as an attractive appearance and the certainty that no one has used or even touched the previously chosen item. PVC film compares favorably with polyethylene film in terms of better optical properties and the possibility of being used for packaging many food products.

The relative simplicity of the technology contributes to the spread of polyvinyl chloride. The granulated starting material (polymer) enters the extruder where it is melted. Then a large bubble is blown out of it, serving as a source of a continuous layer, cut to the desired width, and wound on spools.

PVC film used in foodindustry and trade, it is produced in two types: stretch and heat-shrinkable. Each of them has its own purpose.

Stretch - PVC film is used to wrap the product without creating a weld. It is characterized by special mechanical properties, such as the ability to stretch and interlaminar adhesion due to the occurrence of an electrostatic field and intermolecular attraction. It is widely used by trading organizations to create hygienic conditions for the storage and sale of goods.

PVC shrink film is characterized by its ability to decrease in geometric dimensions under the influence of heat. In order to pack goods into it, two main technological operations should be performed: solder the edges and shrink. It is produced in the form of a half-sleeve (that is, folded in half in width) or a sleeve wound into rolls. Sealing is carried out on industrial welders, most often angle welders, and seating is usually carried out with a stream of heated air.

Depending on the nature of the product to be packaged, the consumer selects the desired size from the range offered on the market. The characteristics of shrink wrap are usually clear from the label. For example, the PVCT code 40075015 printed on the label means that the roll has a half-sleeve width of 40 cm, a length of 750 m, and a single layer thickness of 15 microns.

PVC film manufacturers must indicate the weight. It so happened historically that PVC film is sold by weight.

This species haspackaging materials and a disadvantage - it is impossible to print text or pictures on a shrink film, since any inscriptions will be distorted if the geometric dimensions change. However, it is easy to stick any label on a smooth surface, or, alternatively, put it on the bottom. When choosing this method of product design, you should remember that shrink film creates an outer optically transparent layer that reliably protects against scratches, dust, dirt, and gives any, even a faded box, a glossy shine.

The marking of PVC stretch film is about the same as shrink film, the difference is that it is wound in one layer, and therefore, as a rule, the length of the roll is twice as long.