Что такое ПЭТ?

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What is PET and what is it served with?
Polyethylene terephthalate - PET, PET (PET) is a thermoplastic polyester used in the production of synthetic fibers, films and plastic packaging.
PET is known to the world under other names - lavsan, dacron, mylar, thermoplastic or polyester. Materials produced on the basis of polyethylene terephthalate have an international name - PET. For the Russian consumer today, two abbreviations are relevant: PET - when it comes to polymer, PET - when it comes to products made from it.
International PET mark
PET containers are one of the most famous in the world: plastic bottles, vials, cans and other containers are made of polyethylene terephthalate. It is also widely used in medicine, mechanical engineering, and clothing manufacturing.
PET production
The raw materials for PET are terephthalic acid dimethyl ester and ethylene glycol.
Colorless crystals of terephthalic acid are synthesized with ethylene glycol (liquid) in a special apparatus at 260 degrees - a polyethylene terephthalate melt is formed at the outlet.
The melt is extruded, cooled and granulated or sent to fiber spinning. All the necessary dyes and additives are introduced into the material during synthesis or into the resulting PET melt. Commodity PET material at the outlet is granules with a size of 2-4 mm.
Polyethylene terephthalate is a high molecular weight plastic polymer. It has nothing to do with poisonous low molecular weight phthalate. Dibutyl phthalate plasticizer is not used in the production of plastic containers, since polyethylene terephthalate itself is very plastic.
PET can be in two states:
  • amorphous state: a solid, transparent substance with a grayish-yellowish tint, passes into this state upon rapid cooling
  • crystalline state: solid, colorless, opaque substance, transitions to this state upon rapid cooling

PET has transparency, high strength, good plasticity, high barrier properties. This material lends itself to processing by drilling, sawing, milling. PET material retains all its characteristics at temperatures from -40 to +75 degrees.

Physical properties of PET
  • Thermal expansion coefficient (melt) - 6.55 x10 -4
  • Compressibility (melt), MPa - 6.99 x 106
  • Density, g / cm3: amorphous, crystalline - 1.370, 1.455
  • Dielectric constant (23 ° С, 1 kHz) - 3.25
  • Elongation at break,% - 12-55
  • Glass transition temperature, (amorphous, crystalline PET) - 67, 98 ° С
  • Melting point, ° С (amorphous, crystalline PET) - 225-275 ° С
  • Decomposition temperature - 350 ° С
  • Refractive index (Na line): amorphous, crystalline - 1.576, 1.640
  • Tensile strength, MPa - 172
  • Tensile modulus, MPa - 1.41x104
  • Moisture absorption of PET - 0.3%
  • Permissible residual moisture in PET - 0.02%
  • Frost resistance, up to -50 ° С

The invention of PET and the emergence of PET containers

PET was patented in 1941 by the English company Calico Printers, which received the first synthetic fiber. The copyright for PET was sold to DuPont and ICI, which created the famous Mylar fibers for use in spacecraft.
Until the 60s of the twentieth century, PET was used in the textile industry, later they began to produce packaging film from it. In 1976, DuPont engineer Nathaniel White created the world's first PET bottle.
In the USSR, work on obtaining PET was carried out in 1949 at the Research Institute of Artificial Fibers. At the place of obtaining the material - the Laboratory of Macromolecular Compounds of the Academy of Sciences of the USSR - it was named "lavsan".
PET for bottle use in Russia appeared only at zero. This is also the reason for the beginning of the study of the material at the Research Institute of Plastics, which proved that PET is a pure polymer and one of the most harmless types of plastic.
The first Russian PET plant started operating in 2003 and quickly increased its volume. Today, there are four such factories in Russia, and the food industry's needs for PET packaging are satisfied by 95% - almost ideal economic indicators. By 2020, it is expected to launch an import-substituting enterprise in Tatarstan - SafPet, the Ivanovo polyester complex, as well as the Etana industrial complex in Kabardino-Balkaria.
The production of PET packaging of all shapes and sizes is the most significant field of PET application today. PET containers are used for packing carbonated and mineral waters, vegetable oil, sauces, juices, fermented milk products, beer, kvass, perfumery, household chemicals, pharmaceutical products. At the end of 2016, Russia produced 534 thousand tons of PET (7% more than a year earlier), imports amounted to 108 thousand tons, exports - 36 thousand tons.
PET and ecology
PET containers have gained popularity due to their ease of use, weight, low cost and, most importantly, they are completely inert to the products packaged in them.
PET belongs to the 5th, safest, waste class. The process of production and circulation of plastic containers does not require a large amount of electricity, which also minimizes CO2 emissions into the atmosphere.
PET containers decompose in landfills for 150 years (for example, it takes 500 years for an aluminum can to decompose, and more than a thousand years for a glass can). In addition,  special bacteria Ideonella sakaiensis  201-F6 is capable of  decomposing PET into its original components - to  terephthalic acid  and  ethylene glycol .
PET recycling potential
PET packaging is 100% recyclable. Recycled PET material is used, among other things, for packaging products, since the production of plastic containers is possible both from “primary” raw materials and from “secondary” ones.
The technology for recycling plastic packaging is called bottle-to-bottle. Old bottles are collected, sorted by color, washed, crushed and processed, melting and getting the same PET granulate, only colored. And the granules are again used for the production of PET bottles.
Flex or pellets are also made from recycled PET. Flex is used to produce bristles for brushes of cleaning machines and car washes, packing tape, film, roof tiles, paving slabs. And from pellets - filler for sleeping bags and geogrid for roads.
At the same time, recycling plastic bottles saves 50-60% of the energy that would be needed to produce a product from new materials.