What is polymer waste, its processing and disposal. Properties: Behavior of recycled materials during processing Types of polymer processing

INTRODUCTION

Based on polyvinyl chloride (PVC), more than 3,000 types of composite materials and products are used in the electrical, light, food, automotive industries, mechanical engineering, shipbuilding, in the production of building materials, medical equipment, etc., due to its unique physical and mechanical, dielectric and other operational properties.

However, at present, the use of PVC is gradually limited, which is primarily due to environmental problems that arise during the operation of products, their disposal and recycling. During the aging of PVC-based polymers, along with the loss of physical and mechanical properties, a negative impact on the environment and humans is observed, due to the processes of PVC dehydrochlorination, which increase at a temperature of 50-80 ° C (highly toxic chlorine-containing polyaromatic compounds are formed).

UTILIZATION OF SECONDARY POLYMER RAW MATERIALS

Currently, there are the following ways of beneficial use of recycled polymer raw materials:

Burning for the purpose of obtaining energy;

Thermal decomposition (pyrolysis, destruction, decomposition to initial monomers, etc.);

Reuse;

Recycling.

Waste incineration in incinerators is not a cost-effective disposal method, as it involves pre-sorting the waste. During combustion, there is an irretrievable loss of valuable chemical raw materials and environmental pollution with harmful substances in flue gases.

A significant place in the recycling of secondary polymeric raw materials is given to thermal decomposition as a method of converting EPS into low molecular weight compounds. An important place among them belongs to pyrolysis. Pyrolysis is the thermal decomposition of organic substances in order to obtain useful products. At lower temperatures (up to 600°C), mainly liquid products are formed, and above 600°C, gaseous products, up to carbon black.

Pyrolysis of PVC with the addition of PE, PP and PS waste at T=350°C and pressure up to 30 atm in the presence of a Friedel-Crafts catalyst and when the mixture is treated with hydrogen makes it possible to obtain many valuable chemical products with a yield of up to 45%, such as benzene, toluene , propane, cumene, alpha-methylstyrene, etc., as well as hydrogen chloride, methane, ethane, propane. Despite a number of disadvantages, pyrolysis, unlike HBO combustion processes, makes it possible to obtain industrial products used for further processing.

Another way to transform recycled polymer raw materials is catalytic thermolysis, which involves the use of lower temperatures. In some cases, gentle modes make it possible to obtain monomers, for example, during the thermolysis of PET, PS, etc. The resulting monomers can be used as raw materials in polymerization and polycondensation processes. In the USA, scarce monomers, dimethyl terephthalate and ethylene glycol, are obtained from used PET bottles, which are again used for the synthesis of PET of a given molecular weight and structure required for the production of bottles.

From an economic and environmental point of view, the most preferred ways of recycling polymeric raw materials are reuse and recycling into new types of materials and products.

Reapplication involves the return to the production cycle of the used packaging after its collection and appropriate processing (washing, drying, etc. operations), as well as obtaining permission from the sanitary authorities for its reuse in direct contact with food products. This route is mainly suitable for PET bottles.

Recycling of waste has become widespread in many countries of the world. In this way, mixed waste from polymeric materials can be processed into products for various purposes (building panels, decorative materials, etc.). In the United States, where the use of polyethylene terephthalate containers is especially high, a national program has been adopted and is being implemented, according to which, by the beginning of the 21st century, the level of recycling of PET bottles will be increased to 25-30% (compared to 9-10% in the early nineties) . The program provides for the implementation of four stages: - organizing the collection of used containers from the population; - sorting of the collected raw materials;

Processing (preliminary and final) into products for national economic purposes;

Sales of received products.

The program also provides for the creation of collection points throughout the country with the involvement of up to 50% of the total population, focal points, the establishment of various communications, advertising, the publication of information on waste collection, the creation of a data bank, public education, the creation of "hot" lines (up to 800) for the transfer timely information and other activities. One of the promising areas in this area is the production of granules from sorted raw materials using various additives that improve its quality (stabilizers, dyes, modifiers, etc.), which are processed into products by various processing methods.

The recycling of waste, for example, in Germany is based on the "Dual System", which includes the sorting and processing of certain types of secondary raw materials at enterprises producing materials and packaging from them. To facilitate waste collection and recycling, a system has been put in place to accept used packaging and recycle it with the Green Dot (Der Grune Punkt) environmental label. This mark indicates that this packaging is recyclable or reusable, and is assigned to packages that have passed a special competition, which is the main principle of the "Dual System". Usually, for efficient processing of EPS, it is subjected to modification. There are the following methods of EPS modification: - chemical (crosslinking with peroxides, for example, dicumyl peroxide, maleic anhydride, organosilicon liquids, etc.);

Physico-chemical (introduction of various additives of an organic nature, for example, technical lignins, soot, thermoplastic elastomers, waxes, etc.), creation of composite materials;

Physical (introduction of inorganic fillers: chalk, oxides, graphite, etc.) and technological (variation of processing modes). The introduction of polyorganosiloxanes together with initiating additives and subsequent homogenization of the processed raw materials makes it possible to regenerate heavily worn materials and restore the required level of their technological properties. Depending on the medium used and the processing mode, the formation of graft copolymers or spatially structured systems with the formation of cross-siloxane bonds occurs. Their high strength and low molecular packing density in polysiloxanes ensures the elasticity of the material while improving mechanical properties, thermal stability, weather and chemical resistance.

The mechanical characteristics of secondary PA from worn products can be significantly improved by thermal treatment of raw materials with various heat-transfer media (water, mineral oil, etc.) with simultaneous IR irradiation. Heat treatment in a heat carrier medium is carried out according to the annealing principle and includes the operations of heating, holding and cooling. At the same time, the level of physical and mechanical indicators is determined by the type of heat carrier, heat treatment mode and drying time, which can be from 1.5 to 2.5 hours. Most of the proposed methods are based on the radical chain mechanism of interaction between the active groups of the added additive or filler and the oxidized fragments of the base polymer. Among all available methods, composite materials from recycled polymer raw materials are of the greatest practical interest. One of the functional modifying additives can serve as a natural polymer - lignin, which is a waste of pulp and paper and hydrolysis processing of wood. It is a metabolic product of wood and other plants accumulated during lignification in the median lamina and cell wall, accounting for 30% of its total mass (the remaining 70% are cellulose and hemicellulose).

By its chemical nature, lignin belongs to polyfunctional phenols, the main class of polymer stabilizers, and has a fairly effective light and heat stabilizing effect on oxidized and oxidized polymers. The technology for obtaining a micronized product from it using electromagnetic grinding was developed at MGUPB.

In addition to an effective modifier of secondary polymeric raw materials, hydrolysis lignin after appropriate processing and preparation in the form of hydrolysis flour (microlignin) can be used to obtain such valuable products in plastics processing technology as aromatic stabilizers, antioxidants, structure formers and modifying additives for thermoplastics, fillers - for thermoplastics , sorbents for medical purposes of the "EKOLIS" type for removing toxins, heavy metals and other substances harmful to a living organism from the body, as a drug in the treatment of liver cirrhosis (studyed on rabbits), for the production of vanillin and other purposes. In a number of European countries, the problem of recycling used plastic packaging is inextricably linked with the establishment of a clear service for their collection, sorting and separation of mixed waste, since these operations are the most labor-intensive.

In the EU countries, the issues of packaging waste disposal are solved within the framework of a single law for these countries, aimed at preventing the increase in the volume of polymer packaging and containers, rational methods of their disposal, mainly by recycling, organizing a rational collection system, etc.

Works in the field of utilization of secondary polymer raw materials were started in Russia in the late 70s - early 80s.

PVC recycling

During processing, polymers are exposed to high temperatures, shear stresses and oxidation, which leads to a change in the structure of the material, its technological and operational properties. The change in the structure of the material is decisively influenced by thermal and thermal-oxidative processes.

PVC is one of the least stable industrial carbon chain polymers. The PVC degradation reaction - dehydrochlorination begins already at temperatures above 100 °C, and at 160 °C the reaction proceeds very quickly. As a result of thermal oxidation of PVC, aggregative and disaggregative processes occur - cross-linking and destruction.

The destruction of PVC is accompanied by a change in the initial color of the polymer due to the formation of chromophore groups and a significant deterioration in physical, mechanical, dielectric and other performance characteristics. Crosslinking results in the transformation of linear macromolecules into branched and, ultimately, into crosslinked three-dimensional structures; at the same time, the solubility of the polymer and its ability to be processed are significantly worsened. In the case of plasticized PVC, cross-linking reduces the compatibility of the plasticizer with the polymer, increases the migration of the plasticizer, and irreversibly degrades the performance properties of the materials.

Along with taking into account the influence of operating conditions and the frequency of processing of secondary polymeric materials, it is necessary to evaluate the rational ratio of waste and fresh raw materials in the composition intended for processing.

When extruding products from mixed raw materials, there is a risk of rejection due to different melt viscosities, therefore it is proposed to extrude virgin and recycled PVC on different machines, however, powdered PVC can almost always be mixed with recycled polymer.

An important characteristic that determines the fundamental possibility of recycling PVC waste (permissible processing time, the service life of the recycled material or product), as well as the need for additional strengthening of the stabilizing group, is the thermal stability time.

Methods for the preparation of PVC waste

Homogeneous industrial waste, as a rule, is recycled, and in cases where only thin layers of material are subjected to deep aging.

In some cases, it is recommended to use an abrasive tool to remove the degraded layer with subsequent processing of the material into products that are not inferior in properties to products obtained from the original materials.

To separate the polymer from the metal (wires, cables), a pneumatic method is used. Typically, isolated plasticized PVC can be used as low voltage wire insulation or injection molded products. To remove metal and mineral inclusions, the experience of the milling industry based on the use of the induction method, the method of separation by magnetic properties can be used. To separate aluminum foil from thermoplastic, heating in water at 95–100 °C is used.

It is proposed to immerse unusable containers with labels in liquid nitrogen or oxygen with a temperature not exceeding -50 ° C to make the labels or adhesive brittle, which will then allow them to be easily crushed and separate a homogeneous material, such as paper.

An energy-saving method for the dry preparation of plastic waste using a compactor. The method is recommended for processing artificial leather (IR) waste, PVC linoleums and includes a number of technological operations: grinding, separation of textile fibers, plasticization, homogenization, compaction and granulation; additives may also be added. The lining fibers are separated three times - after the first knife crushing, after compaction and secondary knife crushing. A molding mass is obtained which can be processed by injection molding, which still contains fibrous components which do not interfere with processing, but serve as a filler that reinforces the material.

Products made of polymers are an integral part of our daily lives today, however, along with the growth in the production of such products, it is only natural that the amount of solid waste is also increasing.

Today, polymer waste makes up about twelve percent of all household waste, and their number is constantly growing. And it is natural that the recycling of polymers today is one of the most pressing problems, because without it, humanity can literally drown in mountains of garbage.

The recycling of polymers today is not only a problem, but also a very promising line of business, since it is possible to obtain many useful substances from seemingly waste raw materials - household waste. In addition, this waste recycling technology (MSW) is a much safer method of recycling polymer waste than traditional incineration, which causes significant environmental damage.

Polymer processing technology

So what is polymer recycling?

To convert polymer waste into raw materials suitable for further processing into products, it is necessary to pre-process it. The choice of pre-treatment method primarily depends on the degree of contamination of the waste and the source of their formation. Thus, homogeneous production wastes are usually processed right at the place of their formation, since in this case little pre-treatment is required - just grinding and granulation.

However, waste in the form of obsolete products requires much more thorough preparation. So, the pre-treatment of polymer waste usually includes the following steps:

1. Rough sorting and identification for mixed waste.
2. Waste shredding.
3. Separation of mixed waste.
4. Waste washing.
5. Drying.
6. Granulation.

Pre-sorting provides for a rough separation of polymer waste according to various criteria: type of plastic, color, shape and dimensions. Pre-sorting is usually carried out manually on conveyor belts or tables. Also, the technology of polymer processing implies that various foreign inclusions are removed from the waste during sorting.

Polymer wastes that have become obsolete and have ended up at the waste processing plant, in which the content of foreign impurities does not exceed 5%, are sent to the sorting unit, where random foreign inclusions are removed from them. Waste that has been sorted is crushed in knife crushers until a loose mass is obtained, the particle size of which is 2…9 mm.

Grinding is one of the most important stages in the preparation of waste for processing, since the degree of grinding determines the flowability, particle size and bulk density of the resulting product. And the regulation of the degree of grinding allows you to improve the quality of the material due to the averaging of its technological characteristics. This also simplifies the processing of polymers.

A very promising method of grinding polymer waste is cryogenic, thanks to which it is possible to obtain powders from polymer waste with a degree of dispersion from 0.5 to 2 mm. The use of this technology has a number of advantages over traditional mechanical grinding, since it allows to achieve a reduction in the mixing time and a better distribution of the components in the mixture.

The separation of mixed plastic waste by type is carried out in the following ways:

1. Flotation.
2. Separation in heavy media.
3. Aeroseparation.
4. Electroseparation.
5. Chemical methods.
6. Deep cooling methods.

The most common of these today is the flotation method, in which the separation of plastics is carried out by adding various surfactants to water, due to which the hydrophilic properties of polymers are selectively changed.

In some cases, a fairly effective way to separate polymers is to dissolve them in a common solvent. Processing the resulting solution with steam, PVC, a mixture of polyolefins and PS are isolated, and the purity of the products is not less than 96%.

It is these two methods that are economically more expedient of all those listed above.

Next, the crushed waste polymers are fed into the washing machine for cleaning. Washing is carried out in several steps using special detergent mixtures. The polymer mass squeezed out in a centrifuge with a moisture content of 10 to 15% is fed for final dehydration to a drying plant, where it is dried to a moisture content of 0.2%.

After that, the mass enters the granulator, where the material is compacted, thereby facilitating its further processing and averaging the characteristics of secondary raw materials. The end result of granulation is a material that can be processed by standard polymer processing equipment.

So, it is clear that the processing of polymer waste is quite a difficult task, and requires certain equipment. What kind of polymer recycling equipment is used today?

• Washing lines for polymer waste.
• Crushers of polymers.
• Recycling extruders.
• Belt conveyors.
• Shredders.
• Agglomerators.
• Granulation lines, granulators.
• Sieve substitutes.
• Mixers and dispensers.

If you have all the equipment necessary for processing polymers, then you can get down to business and make sure from your own experience that today waste recycling (MSW) is not only a concern for the planet's ecology, but also an excellent investment, since the profitability of this business is very high.

The use of secondary raw materials as a new resource base is one of the most dynamically developing areas of polymer materials processing in the world. For Russia it is new. However, the interest in obtaining cheap resources, which are secondary polymers, is very tangible, so the world experience in their recycling should be in demand.

In countries where environmental protection is of great importance, the volume of recycling of recycled polymers is constantly increasing. Legislation obliges legal entities and individuals to dispose of plastic waste (flexible packaging, bottles, cups, etc.) into special containers for their subsequent disposal. Today, the agenda is not only the task of recycling waste polymer materials, but also the restoration of the resource base. However, the possibility of using polymer waste for re-production is limited by their unstable and worse mechanical properties compared to the original polymers. The end products with their use often do not meet aesthetic criteria. For some types of products, the use of secondary raw materials is generally prohibited by the current sanitary or certification standards. For example, some countries have banned the use of certain recycled polymers in food packaging.

The process of obtaining finished products from recycled plastics is associated with a number of difficulties. The reuse of recycled materials requires a special reconfiguration of the process parameters due to the fact that the recycled material changes its viscosity, and may also contain non-polymer inclusions. In some cases, special mechanical requirements are imposed on the finished product, which simply cannot be met when using recycled polymers. Therefore, for the use of recycled polymers, it is necessary to achieve a balance between the desired properties of the final product and the average characteristics of the recycled material. The basis for such developments should be the idea of ​​creating new products from recycled plastics, as well as partial replacement of primary materials with secondary ones in traditional products. Recently, the process of replacing primary polymers in production has intensified so much that more than 1,400 items of products from recycled plastics are produced in the USA alone, which were previously produced only using primary raw materials.

Thus, recycled plastic products can be used to produce products that were previously made from virgin materials. For example, it is possible to produce plastic bottles from waste, i.e. recycling in a closed cycle. Also, secondary polymers are suitable for the manufacture of objects whose properties may be worse than those of analogues made using primary raw materials. The latter solution is called "cascade" waste processing. It is successfully used, for example, by FIAT auto, which recycles the bumpers of end-of-life cars into pipes and floor mats for new cars.

We will consider the problems and prospects for the reuse of plastics using the example of polyethylene terephthalate (PET), polyethylene, polypropylene and polystyrene.

PAT

PET has fairly stable mechanical properties. Therefore, secondary material based on it is quite easy to process. The main raw material for recycling are such common plastic bottles from drinks. It is also important that recycled PET homogenizes more easily than other recycled plastics. In developed countries, the collection of PET waste is sufficiently established, as well as the technology for their processing. The global volume of recycling of recycled PET reaches 1 million tons annually.

The process of recycling PET waste does not require their plasticization. They are sorted from other types of plastic containers (PVC or PE based), then shredded, washed and cleaned from labels, adhesives, residues of packaging compounds and other contaminants, and then agglomerated or granulated. Recycled PET polymers have the same processing problems as virgin PET substrates: a low threshold for non-Newtonian behavior (when shear rate affects the change in polymer viscosity), heat sensitivity, and, finally, the need to dry. Moreover, during drying and processing, the recycled material undergoes some loss of viscosity, which is caused not only by temperature and deformation effects during the plasticization of the polymer, but also by the presence of contaminants (moisture, glue, dyes, etc.). These factors lead to a decrease in the molecular weight of the polymer. Table 1 shows the values ​​of strength (σ) and relative elongation (ε) at break of film samples from virgin PET and samples of recycled PET extrusion with pre-drying and without drying. Insufficient drying of the recycled substrate can significantly impair the properties of the recycled material.

Table 1

The area of ​​their further application of recyclable PET waste is determined by their molecular weight. The molecular weight of PET is calculated from its intrinsic viscosity. Table 2 shows the range of its values ​​for various PET applications.

Table 2. Intrinsic viscosity of PET depending on the application

Obviously, the secondary polymers that underlie different types of products and, accordingly, have different molecular weights (intrinsic viscosity), require completely different recycling technologies. Recycled PET can not always serve as a basis for the re-production of original products.

Another problem of PET waste processing is related to the possible presence of PVC in them. Even with careful sorting of PET bottles, there is a chance that PVC and PE impurities will enter the composition of the recycled material. At the processing temperature of PET, PVC decomposes, releasing hydrochloric acid, which causes intense degradation of the polymer. Therefore, it is necessary to minimize the presence of PVC in the composition of PET waste. Permissible PVC content does not exceed 50 ppm.

Most often, PET waste is reused for the production of plastic bottles, films and fibers. The rheological and mechanical properties of recycled PET make it suitable for use in the manufacture of detergent containers, making it a good alternative to PVC and HDPE. Recycled PET is also often used as an intermediate layer in the production of three-layer amorphous film and blow molding of three-layer laminated bottles with outer layers of virgin polymer. The use of co-extrusion of mixtures of recycled and virgin PET can improve the rheological properties of the recycled polymer, making it more suitable for blowing.

An equally important area of ​​application for recycled PET is the production of fibers. The fiber spinning process requires the plasticizable secondary polymer to have the same rheological properties (flow rate gradient and non-isothermal stretching) as the virgin polymer. As a rule, PET fiber formed from a secondary base has mechanical properties that satisfy the conditions for the production of a wide range of products.

Recycled fiber is processed into textiles or woven bases for the production of clothing and carpets. These applications can use up to 100% recycled polymer. Most often, PET fiber is used as a synthetic insulation for winter clothes or as a ready-made plush texture for sewing clothes.

PET fiber has a number of advantages over other synthetic fibers. For example, PET fiber carpets do not fade and do not require the special chemical treatment required for nylon fiber carpets. PET fibers and dye more easily than nylon. PET fiber webs made using the melt-blown technology are used for the production of noise-insulating materials, geotextiles, filtering and absorbing elements, synthetic winterizer. Finally, a small amount of recycled PET is used for the manufacture of automotive components, electrical products, and various fittings by injection molding.

Polyethylene

Low-density polyethylene (LDPE) and linear polyethylene (LLDPE) are used to make films for household packaging (including plastic bags, bags and sacks) and industrial packaging (for example, bags for agricultural fertilizers), which are raw materials for further recycling. In the first case, recycling is quite simple, since the quality of the secondary material is very close to the quality of the primary polymer due to the short life cycle of the product. The polymer is exposed to external factors for a short time and undergoes only a slight breakdown of the structure. To a greater extent, the structure of the material suffers in the process of its regeneration through plasticization. Another source of unsatisfactory properties of recycled material can be the use of wastes with different molecular structures (for example, both LDPE and LLDPE), which inevitably leads to a decrease in the mechanical properties of the resulting material.

When reusing industrial packaging, the situation is somewhat more complicated. As a rule, industrial film has a longer life cycle than household film. Exposure to sunlight, temperature fluctuations, etc. also has a detrimental effect on the polymer structure. In addition, used industrial polyethylene films can contain significant contamination in the form of dust and fine components, which are almost impossible to remove even with the most thorough washing. Naturally, this negatively affects the properties of secondary materials.

The use of all recycled plastics is calculated based on their average properties. In the case of LDPE and LLDPE, it can be argued with varying degrees of certainty that the polymer raw materials of these types of recycled films can be processed under the same conditions (and with approximately the same final properties) as virgin plastics. Examples of LDPE recycling include remanufacturing of film for household and commercial packaging, bags for non-bulk waste, and garden mulch film. The properties of the material of the finished product are very close to those of the primary polymer base, however, the number of "product-to-product" recycling cycles is limited due to the deterioration of the polymer properties during the process of repeated melting of the material. In the last cycle, the recyclable film is suitable only for the production of garden mulch film, which requires rather modest mechanical properties (often ordinary soot is added to it).

Stretch films have polymer additives that act as contaminants, requiring a significant addition of primary raw materials: recycled stretch film is mixed in a low proportion (15-25%) with virgin polymer. In the recycling of agro-industrial film, a number of difficulties arise, caused not only by the deterioration of the mechanical properties of the polymer base and foreign inclusions, but also by photo-oxidative processes that reduce the optical properties of the material. The resulting film again acquires a yellow tint.

Currently, the most promising direction for recycling waste from LDPE and LLDPE (and from any other polymers) is considered to be the creation of intermediate materials to replace traditional wood materials. The main advantage of polymer recycled materials over wood is its biological stability: polymers are not destroyed by microorganisms and can be in water for a long time without jeopardizing the structure. To improve the mechanical properties, various inert additives are introduced into the composition of polymers, for example, powdered wood shavings or fibers. The market for such products is huge. US Plastic Lumber Corp. estimates it at $10 billion.

High-density polyethylene is used to make, for example, canisters for liquid products. The process of processing HDPE waste requires special treatment of secondary products (for example, containers for fuel and lubricants). In addition, there are often problems associated with the destruction of HDPE during the plasticization process due to the large mechanical forces accompanying the process. The scope of recycled HDPE is very wide and is distinguished by a variety of technological processes. It is often used for the production of film, containers of various sizes, irrigation pipes, various semi-finished products, etc. Recycled HDPE has found the greatest use in the production of containers (canisters) by blow molding. The rheological properties of high-density recycled polymers do not allow blowing large containers, so the volume of such canisters is limited. A typical area of ​​use for canisters based on HDPE waste is the packaging of fuels and lubricants and detergents.

Cans can be produced either completely on the basis of polymer waste, or with extrusion with primary granulate. In the latter case, the sec polymer layer forms a core between the two primary polymer layers. Canisters obtained in this way are used for filling detergents by a number of companies (Procter & Gamble, Unilever, etc.).

Another example of mass production from recycled HDPE is irrigation pipes. As a rule, they are made from a mixture of secondary and primary polymers in different ratios. Given that irrigation pipes are not designed to be used under pressure, the mechanical properties of recycled HDPE are well suited for their production. The high viscosity of canister and film recycled HDPE can often be compensated for by the low viscosity of the virgin polymer, whereby impact resistance can be improved. The production of large diameter pipes from recycled HDPE is no problem either: irrigation and drainage pipes are up to 630 mm in diameter.

When using injection molding technology, the percentage of recycled plastic is lower. This technology is applied to cladding panels, municipal waste bins, etc. The cladding panel market is very attractive due to its large capacity. It is estimated that the US market alone consumes 2 billion units of sheathing panels and boards, which are still traditional lumber.

As for the production of film with improved impact resistance and high tear strength, in this case recycled HDPE can only be used with LDPE and LLDPE additives.

Polypropylene

The main source of recycled polypropylene are plastic boxes, battery cases, bumpers and other plastic car parts. To a lesser extent, packaging products made from this material are recycled. The quality of the secondary PP depends on the conditions in which the product was located during operation. The less it has suffered from external influences, the closer the properties of the secondary material to the properties of the primary. However, operating conditions are rarely so favorable. Only in rare cases can automotive plastic components be recycled in a closed loop: for example, Renault's Megane uses recycled PP bumpers to make new ones. As a rule, recycled PP is used for the production of other automotive parts that have less stringent requirements - vent pipes, seals, floor mats, etc. This example fits into the classic cascade recycling scheme.

Recycled PP is also used in various blends with virgin PP or other polyolefins in injection molding (boxes, cases) or extrusion (various profiles and semi-finished products).

Polystyrene

The possibilities of recycling polystyrene waste are much more modest. This is due to less diffusion compared to other plastics and, most importantly, a smaller price difference between raw and recycled materials. In addition, polystyrene products often undergo significant volumetric stretching during production, which complicates recycling and affects the overall cost of disposal. A very small proportion of post-consumer polystyrenes is recycled into raw materials. Examples of recycled polystyrene are insulating panels, packaging materials, pipe insulation and other products that can optimally utilize the good thermal insulation, noise dampening and impact resistance properties of recycled polystyrene. In some cases, the structure of the recycled polystyrene is compacted through the use of special transitional technologies, and the material thus obtained is used in crystalline polystyrene applications. The most interesting application of this material is the production of profiles previously made only from wood (window frames, floors, etc.). In this case, the properties of recycled polystyrene are in no way inferior to the properties of wood, and in terms of the duration of the life cycle under natural conditions, they even surpass it.

Plastic blends

Disposal of products consisting of a combination of different polymers is both time-consuming and promising task. On the one hand, when creating secondary materials with acceptable mechanical properties from plastic mixtures, there is no need for primary (at the municipal level) and secondary (at the level of recycling production) sorting of household and industrial waste, which should positively affect the cost of processing. On the other hand, the properties of the resulting materials are not very good, because the polymers that make up their basis (mainly PE, PP, PET, PS and PVC) are incompatible with each other and form a multicomponent system with low interfacial interaction. Moreover, the presence of contaminants - particles of paper, metal, dyes - leads to a further deterioration of the physical and mechanical properties.

In almost all cases, the properties of the mixture are much worse than the properties of each component separately. To achieve visible success in the disposal of multicomponent waste, it is necessary to carry out processing with the shortest possible cycle. The task is, on the one hand, to avoid unnecessary material costs, and on the other hand, to reduce the processing time, preventing the polymers that make up the material from starting to break down. For this reason, it is necessary to keep the operating temperature low, even though certain components (eg PET) will remain in a solid state and behave like inert fillers. It is also necessary to choose applications that do not require high mechanical properties and do not have significant dimensions. This is the only way to avoid the serious impact of the cost of processing on the final cost of the product, as well as to level the low mechanical properties of the multicomponent polymer by the small dimensions of the products formed from it.

Equipment

Various types of equipment for the processing of polymer waste are produced in all developed industrial countries. There are manufacturers of certain types of equipment for "recycling" in the CIS - for example, JSC "Kuzpolimermash" (Russia), Baranovichi Machine Tool Plant (Belarus).

However, such well-known European companies as Erema GmbH, Artoc Maschinenbau GesmbH, NGR GmbH, General Plastics GmbH (Austria), Gamma Meccanica, Tria S.p.A. have no equal in complex solutions. (Italy), Erlenbach GmbH, Sikoplast Maschinenbau, Heinrich Koch GmbH (Germany), ORVAK (Sweden). Today these companies are actively entering the Russian market.

As part of the CREON Group

Polymer recycling, which is so developed in European countries, is still in its infancy in Russia: separate waste collection has not been established, there is no regulatory framework, there is no infrastructure, and there is no consciousness among the majority of the population. However, market players look to the future with optimism, pinning their hopes on the Year of Ecology, which was announced in the country in 2017 by presidential decree.

The third international conference "Polymer Recycling 2017", organized by INVENTRA, took place in Moscow on February 17. The partners of the event were Polymetrix, Uhde Inventa-Fischer, Starlinger Viscotec, MAAG Automatik, Erema and Moretto; support was provided by Nordson, DAK Americas and PETplanet. The information sponsor of the conference is the Polymer Materials magazine.

“Now the situation is not inspiring, but its improvement is a matter of time,” said Sergey Stolyarov, Managing Director of CREON Group, in his welcoming speech. – With high prices for primary raw materials, the demand for recycled polymers and products from them will grow. At the same time, the emergence of domestic raw materials will shift the structure of primary PET consumption towards fibers and films. In this regard, the use of secondary polymers becomes especially promising.”

At the end of 2016, the global collection of PET for recycling amounted to 11.2 million tons, said Helen McGee, consultant of PCI Wood Mackenzie. The main share fell on the countries of Asia - 55%, in Western Europe 17% of the world volume was collected, in the USA - 13%. According to the expert's forecast, by 2020 the collection of PET for recycling will exceed 14 million tons, and in percentage terms the collection level will reach 56% (now 53%). The main growth is expected at the expense of Asian countries, in particular, China.

At the moment, the highest level of collection is observed in China, it is 80%, and other Asian countries have reached approximately the same figure. According to Ms. McGee, out of PET collected in 2016 (and this, we recall, 11.2 million tons), production losses amounted to 2.1 million tons, respectively, 9.1 million tons of flakes were obtained. The main direction of further processing is fibers and threads (66 %).

By 2025, 60% of household waste will be recycled in Europe, in 2030 this figure will grow to 65%. Such amendments are planned to the Waste Framework Directive, said Kaspars Fogelmanis, Chairman of the Board of Directors of Nordic Plast. Now the level of recycling is much lower - in Latvia, for example, it is only 21%, on average in Europe - 44%. At the same time, the volumes of plastic packaging produced in the Baltics are growing every year, the most common recyclable polymers are LDPE, HDPE and PP film.

In Russia, in 2016, the consumption of recycled PET (rePET) amounted to about 177 thousand tons, of which 90% fell to domestic collection. According to Konstantin Rzayev, Chairman of the Board of Directors of EcoTechnologies Group, almost 100% of imports fell on PET flakes for the production of polyester fiber. The largest supplier countries are Ukraine (more than 60%), as well as Kazakhstan, Belarus, Azerbaijan, Lithuania and Tajikistan.

Konstantin Rzayev noted that last year the collection rate for the first time exceeded 25%, and this allows us to speak about the emergence in Russia of a full-fledged industry that is already of interest for investment. Today, the main consumer (62% of the total volume) and the price driver is still the recycled PET fiber segment. But changes in legislation and the trend towards the priority use of recycled materials as part of the sustainable development strategies of multinational consumer goods companies provide fertile ground for the development of another key segment of rePET consumption - bottle-to-bottle.

Over the past year, there were no new large-scale productions consuming rePET, but its use in the sheet segment is gradually growing. However, already in 2017, it is expected to open new recycled PET fiber production facilities and expand existing ones, which, together with the ruble exchange rate, will be the main factor influencing the market balance and prices for rePET.

However, there are many other areas - still undeveloped, but quite promising, where recycled PET is also in demand. According to ARPET Honorary President Viktor Kernitsky, these are threads for furniture fabrics, car upholstery and various types of geosynthetics, foamed materials for heat and sound insulation, sorption materials for wastewater treatment, as well as fibers reinforcing bitumen for road construction. According to the expert, there are many new processing technologies and applications, and the goal of state policy should not be to limit the use of PET, but to collect and rationally use its waste.

The topic was continued by Lyubov Melanevskaya, Executive Director of the RusPEC Association, who spoke about the first results of the introduction of extended producer responsibility (EPR) in Russia. It entered into force in 2016, its goal is to create a constant, solvent and growing demand for the recycling of product and packaging waste. After a year, it is already possible to draw some conclusions, the main of which is that there are a number of problems due to which the mechanism for the implementation of the RPR often simply does not work. As Ms. Melanevskaya said at the conference, there is a need to change and supplement the existing regulation. In particular, when declaring goods, including packaging, manufacturers encountered a discrepancy between the codes for the packaging of goods and the codes specified in the adopted regulatory acts, as a result of which many manufacturers and importers were unable to file declarations, because. did not find themselves in regulation. The solution was the rejection of codes and a proposal to switch to the identification of packaging by materials.

In the future, according to RusPEC, it is necessary to adopt a single end-to-end terminology for all elements of the RPR and determine unambiguous, understandable and transparent conditions for concluding contracts with waste management operators. On the whole, the association supports the law on EPR as necessary and positive for the industry.

When introducing and popularizing PET recycling in the country, the availability of modern technologies (as a rule, they are provided by foreign companies) is of great importance. For example, Polymetrix offers state-of-the-art integrated PET recycling solutions, including its own SSP technology, for recycling PET bottles into food bottled polyethylene terephthalate. Now there are 21 such lines in the world, said Danil Polyakov, regional sales manager. The technology is aimed at the premium market and involves the processing of bottles into pellets for food containers. The first step is the wash, where paper fibers and surface contaminants are completely removed, as well as labels and glue. Next, the bottles are crushed into flakes, which are sorted by morphology and color. Then there is the production of granules and then - the final complete purification and restoration of the characteristics of the polymer at the SSP stage.

Viscotec offers its customers the technology to convert PET bottles into sheets, says company spokesman Gerhard Osberger. For example, the viscoSTAR and deCON solid phase polycondensation reactors are designed to purify and increase the viscosity of PET pellets and flakes. They are used after the granulator, before the production extrusion equipment or as a stand-alone unit. The ViscoSHEET line is capable of producing tape made from 100% recycled PET and fully food grade.

Christoph Wjoss, a representative of Erema, spoke about the in-line production of food-grade plastic bottles from PET flakes. The VACUREMA® inline system allows you to process flakes directly into finished thermoforming sheet, bottle preform, finished packaging tape or monofilament.

Summing up the results of the conference, its participants identified the main factors hindering the development of polymer recycling in Russia. The main one they called the lack of regulatory documents:

“Nevertheless, there is one more factor that we cannot ignore, and that is the public consciousness,” says Rafael Grigoryan, director of the conference. “Unfortunately, our mentality today is such that the separate collection of waste is perceived more as pampering than as the norm. And no matter what progress we see in other areas, it is necessary first of all to change the thinking of our fellow citizens. Without this, even the most modern infrastructure will be useless.”

Recycling of polymers in Russia is becoming more and more promising. The number of projects for separate collection of waste is increasing, and products made using such materials are widely used in various industries. However, the development of the market is still hindered by a number of factors.

On February 16, the Fourth International Conference "Polymer Recycling 2018" was held in Moscow. The partners are Viscotec and KRONES, the general media partner is the Polymer Materials magazine. The event was supported by INTRATOOL, EREMA and PETplanet.

General Director of INVENTRA Rafael Grigoryan, welcoming the participants, noted that in the future regional operators can become the largest players in the segment of polymer recycling. Their main source of income today is the waste management tariff paid by the population, but the volume of incoming funds may not be enough to make a profit. In this regard, regional operators with an extensive resource base are interested in sorting, processing and producing goods from recycled materials in order to derive maximum benefit.

The discussion of the state of affairs in the segment began with a speech by the Chairman of the Board of Directors of the Clean City Group of Companies, Polina Vergun, who said that the area of ​​waste management in Russia is as follows: 5% is sent for processing, 10% goes to landfills that meet environmental requirements, and 85% end up at facilities that do not provide environmental safety.

Among the main problems of the industry, Ms. Vergun singled out: the placement of waste in unauthorized landfills and the lack of a sufficient number of waste management facilities. And the main difficulties in the recycling segment are the lack of sorting and processing capacities, the fragmentation of the market and the underdevelopment of the separate collection system.

The solution to the above problems, according to the speaker, has already been found: the introduction of the institution of a regional operator in the field of waste management, a ban on the disposal of individual components and an increase in the rates and standards of the environmental fee. The expert also noted that the participation of small businesses in the organization of waste management activities is important.

“Given the ongoing waste management reform, it is important to start building federal ecotechnoparks that process secondary raw materials, which will be taken from the regional technoparks that are currently being commissioned today, because the existing processing capacities will not be enough for the volumes of recyclables in the new system, - continued Ms. Vergun, - within its framework, interaction takes place at the level of regional and federal ecotechnoparks, directions for processing secondary raw materials for the purpose of import substitution are determined and joint solutions are developed to improve the regulatory framework , including the rationale for increasing the standards and recycling rates.
In addition, the speaker noted that in the next few years the collection of plastic waste will increase significantly and it is not entirely clear whether there is a sufficient volume of consumption of products made from recycled polymers in Russia today. “We are ready to give certain capacities on our territory for the development of third-party enterprises, if it is expedient and beneficial to both parties,” concluded Ms. Vergun.

The Chairman of the Board of Directors of Ecotechnology, Konstantin Rzayev, spoke about his vision of the situation and recalled that in total Russia consumes 5 million tons of polymer raw materials, an impressive part of which remains in use for decades (window frames, pipes, geomaterials), and in “garbage” first of all, polymer packaging gets into.

According to the speaker, taking into account the expected sharp increase in the collection of plastic waste at sorting by the efforts of regional operators, an additional 100-150 thousand tons of PET and several hundred thousand tons of other polymer packaging can be expected in the next few years.

Mr. Rzayev, continuing the conversation, noted that the previous two or three years had set some trends in the field of plastic waste processing, there were factors that led to the growth of the industry and new opportunities. Among these, the speaker noted the adoption of laws 458 and 503 F3, the introduction of extended producer responsibility, the launch of an increasing number of waste sorting complexes, as well as the implementation of a ban on waste disposal, which includes useful components, which began in 2018. Territorial schemes have been developed in almost all regions, about a third of them have chosen recyclers for the treatment of MSW, more and more organizations are learning about extended producer responsibility and environmental fees.

Of course, environmental friendliness is becoming a trend. But the segment still has problems: the low collection of fractions for processing, the high proportion of players remaining "in the shadows", the unstructured industry - will this change in the coming year? The question remains open.

The expert estimated the consumption of recycled PET (in the form of PET flakes) for 2017 at 151 thousand tons, of which domestic production is 136 thousand tons, about 16 thousand tons were imported, and 877 tons were exported. Almost 100% of imports - PET flakes for the production of polyester fiber. Among the largest supplier countries: Ukraine, Belarus-Kazakhstan-Kyrgyzstan, Lithuania, Azerbaijan and the UK.

The structure of consumption of recycled PET today is as follows: 65.4% falls on polyester fiber, about 18% - preforms, 12.7% - tape, twine, film and sheets - 2.7%, and less than 1% - other segments (resins, etc.). ) The largest processors - manufacturers of polyester fiber (Comitex, RB-Group, Technoplast, Politex, Nomatex, Selena, Vtorkom), Specta (leader in the Russian packaging tape market), as well as the only manufacturer of food-grade PET granulate, the Plarus plant.

The volume of deliveries of recycled polyethylene to Russia, for comparison, in 2014 was 1.9 thousand tons, by 2016 it rose to 3.3 thousand tons, but in 2017 it dropped again and amounted to about 3.1 thousand tons. Among the largest suppliers according to the data over the past year - Poland (2.2 thousand tons) and Bulgaria (777 tons).

In Europe, an average of 492 kg of waste per person per year is produced, of which a smaller part - 42% is recycled, and the remaining 58% is buried or incinerated, Kaspars Fogelmanis, CEO of PET Baltija, said in his report on plastics recycling in Europe.

Today, almost 50% of all plastic collected and recycled in the EU comes from France, Germany and Italy. These countries are joined by Spain and the UK, forming the top five players and collecting about 71% of the total waste in the EU. The European Commission has proposed to increase the percentage of recycling of the entire flow of plastic waste in the EU to 55% by 2025.

PET waste imports to China decreased in the 3rd quarter of 2017 by 177.6 thousand tons, or 26% compared to the figures for 2016, which amounted to 517 thousand tons. By the end of 2017, the Chinese authorities banned the import of 24 types of materials, including paper and plastic. From now on, they will only accept recyclable materials with a pollution level of no more than 0.3%, according to the government of the country.

Clearly, the ban imposed by China has an impact on recycling worldwide: this extends to the EU-27 countries, where 87% of the collected recycled plastic is shipped directly or indirectly via Hong Kong to China. Japan and the US are also taking advantage of China buying up their recycled plastic. Last year, America exported 1.42 million tons of plastic waste, which, according to Mr. Fogelmanis, brought China nearly $500 million.

Lyubov Melanevskaya, executive director of RusPEC, made a report on the mechanisms for implementing extended producer responsibility (which are provided in two ways: independently or through payment of an environmental fee).

“According to the plan, the state in 2017 was supposed to collect 6.5 billion rubles. as an environmental fee, but in fact collected 1.3 billion rubles. What does it take to make ROP work? Clear rules of the game, equal contribution of business, the state and the population, as well as support for the “first swallows” in the independent implementation of the ROP,” shared Ms. Melanevskaya.

Success in the current situation, according to the speaker, can lead to the synchronous adoption of legislative acts, giving obligations to the authorities to introduce separate waste collection and responsibility for failure to achieve targets for the RSO, as well as the introduction of infrastructure for the RSO. The North Ossetia Law, adopted at the end of 2017, marked the beginning of changes. Will there be further improvements? Time will tell.

Anna Dautova, head of the TechnoNIKOL project, believes that in Russia there is still no culture and widespread practice of collecting and processing polystyrene waste, but this process can be led by their company, and then an important environmental problem on a national scale will be solved.

Recycling of polystyrene waste requires less than 10% of the total resources spent on the production of virgin polymers. At the same time, for the production of a number of products, secondary ones can be used in large volumes. Speaking about the world experience, the speaker noted that Torox and Ursa are the main players in the European polystyrene recycling market. According to the data provided by the speaker, 50 thousand tons of expanded polystyrene are recycled annually in Europe, and in Japan, with a market capacity of primary foamed polystyrene of 132 thousand tons, 125 thousand tons are collected and reused.

Kaloyan Iliev, General Director of the Yerema subsidiary, presented information on pre-vacuum treatment at elevated temperature before extrusion, due to which, in a stable technological environment, moisture and migratory substances are removed from the material already before extrusion. This processing and the short extrusion screw ensure continuous production of food grade approved PET pellets with high and stable viscosities and good color values.

Global waste collection rates are on the rise, with Asia leading the way. The legislation is getting stricter: recycling of materials is encouraged and at the same time restrictions on waste disposal and energy use are introduced, which, of course, should have a positive impact on the global environment, said Peter Hartel, head of sales at Krones, and spoke about the decisions of the plastics recycling company. Krones modular systems are fully customizable and can be supplied as individual machines or as turnkey plants. MetaPure processing technology produces flakes or granules of various qualities, up to food grade PET in accordance with the FDA and other certification systems.

In conclusion, the conversation turned to PET packaging. According to Starlinger Viscotec representative Gerhard Ossberger, there are three conditions for successful PET packaging: optical appearance (bright color, full transparency and no defects), food safety (100% safe packaging for human health), mechanical characteristics (maximum stackability and warehousing, strength). The deCON dryer and viscoSHEET extrusion line removes dust to reduce visual blemishes, dries raw materials for maximum viscosity yet maximum strength, and cleans incoming recycled materials for 100% food safety. In this way, Viscotec creates high-quality "protection" for the goods.