The widest range of polymeric materials is represented by polyethylene terephthalate (PET) products. The materials of this group have a lot of advantages and unique properties that determine demand in various industries. Inside this segment, PET film is especially popular. What it is? This is a form of release of thin polymer-based roll material that can perform many different tasks.
Raw material basis
The film is made of a thermoplastic polymer in the form of polyethylene terephthalate, which is characterized by increased strength, transparency and ductility. Depending on the specific manufacturing technology, the product can also be given improved chemical resistance properties and even the ability to withstand extreme temperatures. For example, PET preforms can withstand from -40 to 75 ° C on average.
At the stage of production of the PET film, the polymer is used in the form of a synthetic fiber. Roughly speaking, this is a plastic mass similar to plasticine, from which any material can be obtained by extrusion under pressure. The product is literally squeezed out of a special apparatus, after which it is cooled and, if necessary, redirected to additional molding procedures. At the same stage, various fillers, dyes, and other additives can be introduced into the composition of the future film product, which have the same improving effect on individual qualities.
Product performance
Basically, the properties of the product are determined by the basic set of qualities of raw materials, but, as already mentioned, in the process of production processing polyethylene terephthalate can be modified. In its pure form, the PET film is transparent, amorphous, heat-resistant and environmentally friendly. However, in special versions, the following qualities can be improved:
- Refractoriness - due to the inclusion of flame retardants.
- Mechanical strength - achieved by strengthening the polymer chain, which leads to an increase in crystallization ability.
- An increase in the melting temperature and reinforcement inside the structure are the effect of adding a phenylene group.
- Anti-sticking.
- High adhesive ability.
Key Specifications
Finished products made of polymers at the stage of technological design are calculated for certain loads, which fully applies to PET film. What is this in terms of specific characteristics? Today there is no single standard that would regulate the technical performance formats of this product, but the average parameters can be represented as follows:
- Roll width - up to 900 mm.
- The thickness of the roller is about 10 mm.
- Film thickness - from 125 to 175 microns.
- Density - 1.4 g / cm3.
- The range of operating temperatures is from -70 to 150 ° C.
- The shrinkage coefficient is about 3%.
Together, these characteristics with dielectric, water-repellent and heat-resistant qualities determine the estimated service life, which can exceed 10 years.
Varieties of PET Film
On the basis of polyethylene terephthalate, a lot of film products are produced, which differ not only in special operational properties, but also in a structural device. On this basis, taking into account the specifics of the application, the following types of material can be distinguished:
- Packing tape. The base segment, in which multilayer film coatings-laminates were originally introduced. Today, such material is used to make casings for various food products, household chemicals, feed, etc.
- Printing film. A more rigid type of material in construction, which is thoroughly used for external lamination. The same group includes PET film in sheets, which covers various printing products in order to protect against mechanical damage.
- Insulation film. A special modification of PET coatings intended for the electrical protection of electronic machines and devices without compromising their functionality. Some versions of this film are used for cable sheathing.
- Metallized film. It belongs to the construction field of application and is a thin polymer base, on the surface of which an alloy of particles of silver, gold, nickel or chromium is sprayed. Such a PET film is also used on windows made of metal-plastic. In the market, such products are known as heat-saving films.
Applications for PET film
The main purpose of the material is related to the manufacture of containers for a wide variety of products from small bottles to bulky equipment. In this quality, the film is used both in industry and in everyday life. Triplex models are widely used for packaging aseptic and hot products with temperatures up to 100 ° C. In some areas, the practice of using such a film is becoming obsolete. For example, not so long ago a radio engineering film was produced from polyethylene terephthalate for cassettes of audio and video recorders, but today products with a similar structure are used only as part of film conditioners. Conversely, in construction there is a great interest in composite products based on PET films. What it is? These are heavy duty thick garbage bags. Construction waste presents a lot of problems during cleaning due to the risks of cuts and punctures in ordinary bags, so reliable and practical PET containers are in great demand.
Material recycling
Recycling from polymers is technologically difficult to obtain, but recently, with the development of new equipment for recycling used products, recycling processes have been greatly simplified. By the way, polyethylene terephthalate PET film in terms of processing capabilities is considered one of the most convenient polymer materials, since it does not require special crushing and crumbling, as is the case with PET bottles, for example. Another thing is that film materials cause more problems at the stages of assembly, sorting and distribution.
Conclusion
Film products based on polyethylene terephthalate today are an indispensable technical product that is widely used in industries for various purposes. Despite the existence of analogues from other synthetic materials, it is PET film that wins the unconditional competition in its niche of packaging materials due to the unique combination of performance. What is this in practice? What does this material deserve such trust from the consumer? Even if you do not take into account the mentioned technical characteristics and protective properties with durability, an important advantage of a PET film is its environmental cleanliness. It is this factor that allows the use of this material in the food industry in large volumes.