Recycling and recycling of polymer materials. Recycling of polymer products Characteristics of the properties of polyethylene foam before and after aging

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

On February 16, the Fourth International Conference “Polymer Recycling 2018” was held in Moscow. The partners were Viscotec and KRONES, the general information partner was the Polymer Materials magazine. The event was supported by INTRATOOL Group, EREMA and PETplanet.

INVENTRA General Director Rafael Grigoryan, welcoming the audience, noted that regional operators in the future could become the largest players in the polymer recycling segment. Their main source of income today is the waste management tariff paid by the population, but the volume of incoming funds may not be sufficient 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 extract maximum benefits. The discussion of the state of affairs in the segment began with a speech by the Chairman of the Board of Directors of the Group of Companies “ Clean city

» Polina Vergun, who reported that the waste management sector in Russia is as follows: 5% is sent for recycling, 10% goes to landfills that meet environmental requirements, and 85% ends up at facilities that do not ensure environmental safety.

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 environmental collection. The expert also noted that the participation of small businesses in organizing waste management activities is important.

“Taking into account the ongoing waste management reform, it is important to begin the construction of federal eco-technoparks that process secondary raw materials, which will be selected from the regional technoparks currently being commissioned today, because the existing processing capacities will not be enough for the volumes of recyclable materials in the new system, - continued Ms. Vergun, - within its framework, interaction takes place at the level of regional and federal eco-technoparks, directions for processing recyclable materials for the purpose of import substitution are determined and developed joint solutions to improve the regulatory framework, including justification for increasing recycling standards and 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 today in Russia there is a sufficient volume of consumption of products made from secondary polymers. “We are ready to provide certain capacities for development on our territory third party companies, if it is appropriate and beneficial to both parties,” Ms. Vergun concluded.

Chairman of the Board of Directors of Ecotechnology Konstantin Rzaev spoke about his vision of the situation and recalled that in total 5 million tons of polymer raw materials are consumed in Russia, an impressive part of which remains in use for decades (window frames, pipes, geomaterials), and ends up in “garbage” First of all, polymer packaging is included.

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

Mr. Rzayev continued the conversation by noting that the previous two to three years had set some trends in the field of plastic waste processing, factors had emerged that entailed industry growth 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 all more waste sorting complexes, as well as the implementation of the ban on the disposal of waste that contains useful components, which began in 2018. Territorial schemes have been developed in almost all regions, approximately a third of them have chosen re-operators for the management of MSW, and 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: low scale of collection of fractions for processing, a high proportion of players remaining “in the shadows”, 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 was 136 thousand tons, approximately 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 supplying countries: Ukraine, Belarus-Kazakhstan-Kyrgyzstan, Lithuania, Azerbaijan and the UK.

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

The volume of supplies 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 approximately 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 is produced per person per year, of which a smaller portion is recycled - 42%, and the remaining 58% is landfilled or incinerated, reported CEO PET Baltija Kaspars Fogelmanis in his report on plastic 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 volume in the EU. The European Commission has proposed increasing the recycling rate of the entire EU plastic waste stream to 55% by 2025.

Imports of PET waste 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. According to the government, from now on they will only accept recyclable materials with a pollution level of no more than 0.3%.

It is clear that the ban imposed by China is affecting recycling around the world: this extends to the EU-27 countries, where 87% of recycled plastic collected 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 Mr. Fogelmanis estimates 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 was supposed to collect 6.5 billion rubles in 2017. as an environmental fee, but in fact they collected 1.3 billion rubles. What does it take for ROP to work? Clear rules of the game, equal contribution of business, the state and the population, as well as support for the “first signs” of independent implementation of EPR,” shared Ms. Melanevskaya.

Success in the current situation, according to the speaker, can be achieved by the simultaneous adoption of legislative acts, the assignment of obligations to authorities to implement separate waste collection and responsibility for failure to achieve target indicators for waste disposal, as well as the introduction of infrastructure for waste disposal. The RSO Law, adopted at the end of 2017, marked the beginning of changes. Will there be further improvements? Time will show.

The head of the TechnoNIKOL project, Anna Dautova, 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 polystyrene waste requires less than 10% of the total resources spent on the production of primary polymers. At the same time, secondary materials can be used in large quantities to produce a number of products. Speaking about global experience, the speaker noted that the companies Torox and Ursa are the main players in the European market for polystyrene recycling. According to the data provided by the speaker, 50 thousand tons of foamed polystyrene are recycled annually in Europe, and in Japan, with a primary foam polystyrene market capacity of 132 thousand tons, 125 thousand tons are collected and reused.

The general director of the Erema subsidiary, Kaloyan Iliev, presented information on preliminary vacuum treatment at elevated temperatures before extrusion, due to which, in a stable technological environment, moisture and migratory substances are removed from the material before extrusion. This processing and short extrusion screw ensure the continuous production of food-grade PET granules with high and stable viscosity values ​​and good color properties.

Global waste collection rates are increasing, with Asia leading the way. Legislation is becoming stricter: the recycling of materials is encouraged and at the same time restrictions are introduced on waste disposal and energy use, which should definitely have a positive impact on the global environment, said Peter Hartel, head of the Krones sales department, and spoke about the company’s solutions for plastic recycling. Krones modular systems are fully adaptable to individual needs and can be supplied as individual machines or as turnkey plants. MetaPure processing technology produces flakes or granules in a variety of qualities, up to food grade PET in accordance with the FDA and other certification systems.

Finally, 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, complete transparency and no defects), food safety (100% safe packaging for human health), mechanical characteristics(maximum stackability and storage, strength). The deCON dryer and viscoSHEET extrusion line removes dust to reduce visual defects, dries raw materials to ensure maximum viscosity while maintaining maximum strength, and cleans incoming recycled materials for 100% food safety. In this way, Viscotec creates high-quality “protection” for the product.

Thermoplastics are plastics that, once molded into a product, remain recyclable. They can repeatedly soften when heated and harden when cooled without losing their properties. This is precisely why there is great interest in the recycling of thermoplastic waste, both domestic and industrial.

Composition of solids household waste(MSW) in the capital differs markedly from the Russian average. Every year about 110 thousand tons of solid household waste are generated in Moscow. Of these, 8-10% are polymer, and in commercial waste from large enterprises this figure reaches 25%.

Plastic bottles should be highlighted separately in the structure of solid waste. Every year in Moscow alone, about 50 thousand tons of them are thrown away. According to the results of the International Scientific and Practical Conference “Packaging and the Environment”, 30% of all polymer waste bottles are made of polyethylene and polyvinyl chloride. However, at present, according to the State Unitary Enterprise Promotkhody, in Moscow and the region no more than 9 thousand tons of polymer waste separated from solid waste are processed annually. And half of them are in the Moscow region. What are the reasons for such little recycling of thermoplastic waste?

Organizing the collection

Today, several channels for collecting plastic waste are used.

The first and main one is the collection and removal of large waste shopping complexes. These raw materials are predominantly used packaging and are considered the “cleanest” and best suited for further use.

The second way is selective garbage collection. In the southwest of Moscow, the city administration, together with the State Unitary Enterprise Promotkhody, is conducting such an experiment. Special German Euro containers have been installed in the courtyards of several residential buildings. Container lids with holes: round - for PET bottles, large slot - for paper. Containers are locked and constantly monitored. In two years, 12 tons of plastic bottles were collected. Today the project includes only 19 residential buildings. According to experts, when covering a territory with more than 1 million inhabitants, the benefits of such a system become obvious.

The third option is the sorting of solid waste at specialized enterprises (experimental industrial waste sorting center "Kotlyakovo", private enterprise MSK-1, other waste sorting complexes). It is still quite difficult to accurately determine the volume of sorted waste, but the share of this source of secondary raw materials is already noticeable. Some commercial organizations, under the control of municipal authorities, organize their own collection points for secondary raw materials (including polymer waste) from the population. Primary sorting and pressing usually take place there. However, there are very few such points in the city.

A significant share of secondary raw materials used for processing is collected illegally at landfills. This is done by private companies, and sometimes by the management of the landfills themselves. Collected and sorted materials are sold to resellers or directly to manufacturers.

When processing thermoplastics, the uniformity of the polymers used, the degree of contamination, color and type (film, bottles, scrap), and the form of the supplied waste (compressed, packaging, etc.) are very important. Depending on these and a number of other parameters, the degree of suitability of a particular batch for further processing (and, consequently, its market value) may vary significantly. Waste paper is the most expensive.

Sorting, crushing and compaction can be carried out by numerous intermediaries, waste sorting complexes, processors themselves, and structures of the State Unitary Enterprise "Industrial Waste".

In most cases, manual sorting is used, since the appropriate equipment is expensive and not always effective.

Polymer processing

Collected and sorted waste can be processed into secondary granulate or directly used for the production of new products (shopping bags and packages, disposable tableware, cases for video cassettes, country furniture, polymer pipes, wood-polymer boards, etc.).

Processing of polymer household waste into industrial scale in Moscow, only OJSC NII PM is engaged in the production of products for the needs of the municipal economy as part of the program for separate waste collection in the South-Western Autonomous District and by order of the capital's mayor's office. State Unitary Enterprise "Promotkhody" carries out crushing, washing and drying, then the flakes at a price of $400 per ton are transported for further processing to the Research Institute of PM.

Other processors of secondary raw materials are either too small (capacity up to 20 tons per month), or under the guise of processing they are engaged in crushing and further resale; at best, they add crushed raw materials to their products. Almost no one is engaged in large-scale production of secondary granulate and agglomerate in Moscow.

According to other information (N.M. Chalaya, NPO "Plastik"), many small companies are engaged in processing polymers contained in Moscow waste, for which this activity is not their main activity. They try not to advertise it, since it is generally accepted that the use of recyclable materials in the production of products worsens its quality.

Typical company for of this market is the Vtorpolymer production cooperative, which works directly with the city landfill. The homeless people who live at the landfill collect everything plastic there: bottles, toys, broken buckets, film, etc. For a certain fee, the “product” is handed over to intermediaries, and they deliver it to Vtorpolymer. Here, worn-out items are washed and sent for recycling. They are sorted by color, crushed and added to plastic, which is used to make installation pipes (they are used in the construction of new houses to insulate electrical wiring). The purchase price of dirty plastic scrap is 1 thousand rubles. per ton, clean - 1.5 thousand. Smaller lots are accepted at prices of 1 and 1.5 rubles. per-kg respectively.

Sorting of polymer waste is carried out manually. The main selection criterion is appearance products or corresponding markings. Without markings, packaging made of polystyrene, polyvinyl chloride or polypropylene cannot be visually distinguished. Bottles are most often considered PET, film - polyethylene (the specific type of PE is usually not determined), although it may well turn out to be PP or PVC. Linoleum - mainly PVC, foamed polystyrene (foam) is easily identified visually, nylon fibers and products technical purpose(spools, bushings) are usually made of polyamide. The probability of matches with this sorting is about 80%.

An analysis of the activities of companies operating in the secondary materials market allows us to draw the following conclusions:

1) prices of recycled materials on the market are determined by the degree of their preparation for processing. If we take the cost of primary low-density polyethylene granulate as 100%, then the price of pure crushed polyethylene film prepared for processing ranges from 8 to 13% of the cost of the primary polymer. The price of polyethylene agglomerate is from 20 to 30% of the cost of the primary polymer;

2) the price of most granular secondary polymers, averaged by composition, ranges from 45 to 70% of the price of primary polymers;

3) the price of secondary polymers strongly depends on their color, that is, on the quality of preliminary sorting of polymer waste by color. The difference in the price of secondary polymers of pure and mixed colors can reach 10-20%;

4) prices for products made from primary and secondary polymers are, as a rule, almost the same, which makes the use of secondary polymers in production extremely profitable.

On average, the price of polymer waste separated from solid waste, depending on the degree of preparedness, batch and type, ranges from 1 to 8 rubles/kg. Purchase prices from processors depending on the batch and level of contamination are shown in Table 1.

The price of clean MSW waste is usually equal to the price of industrial and commercial waste.

The market price for the purchase by a processor of polymer waste from solid waste consists of the price of purchase by an intermediary from the population (approximately 25% of the cost), fees for the formation of large-scale batches of waste, sorting, pressing and even washing for the most expensive (clean) raw materials.

Prices for products such as agglomerate and granulate average 12-24 rubles/kg (polyamide is more expensive than others - 35-50 rubles/kg, PET - from 20 rubles/kg). Further processing increases the added value depending on the type of product by 30-200 %.

Investment attractiveness

According to most experts, investing in the processing of polymer waste is profitable, but only if supported by government support and legislative framework, focused on the interests of processors of secondary raw materials.

Today the Moscow market consists of 20-30 small companies engaged in the processing of polymer waste, mainly of industrial origin. The market as a whole is characterized by informal connections between processors and suppliers, a large share of companies for which this business is a side business, as well as low processing volumes (12-17 thousand tons per year). It can be assumed that if there is a stable demand for such waste from processors, the supply volumes will increase.

It should be noted that the amount of polymer waste that is actually recycled today constitutes a very small part of urban solid waste. And this despite the fact that the demand for polymers and products made from them is constantly increasing, and the problem of waste disposal is increasingly worrying city authorities.

A limiting factor in the construction of new processing plants is the underdevelopment of the waste collection system and the lack of serious suppliers. The coincidence of interests of private business and the state in this area should inevitably lead to the adoption of laws that meet the interests of recyclers.

Present and future

1. The annual volume of PET processing in the capital is 4-5 thousand tons per year. The plans of the Moscow authorities include organizing a system for the selective collection of PET containers by 2003 and creating two production complexes for its processing with a capacity of 3 thousand tons per year. Currently, the construction of two private PET processing plants with a total capacity of six thousand tons annually is being completed.

In the coming months, the Moscow government should adopt regulations regulating the activities of polymer processors (their exact content is not yet known). Existing and under construction capacities are sufficient to meet market needs. The possibility of state support for the projects of the State Unitary Enterprise "Promotkhody" and the company "Inteko" (potential processing capacity - 7-8 thousand tons per year) is being considered.

2. The volume of PP recycling in Moscow is 4-5 thousand tons per year, although about 50-60 thousand tons are thrown away annually in the city - mainly film and big bags. After processing, PP in the form of granules is added to primary raw materials or is used entirely for the production of plastic utensils, shopping bags, etc.).

The absence of large-scale projects for the recycling of this polymer (as is the case with PET) opens up wide opportunities for investment. The most profitable at this stage is the processing of recyclable materials into granulate, since in the field of production of consumer goods the competition is much tougher.

3. The volume of PE processing is also 4-5 thousand tons per year. The main type of raw material is film, including agricultural film. In total, about 60-70 thousand tons of polyethylene waste are thrown out in the city every year. As a rule, enterprises processing PE also deal with PP. One of the large companies through which about 2.5 thousand tons per year passes is Plastpoliten.

PE is characterized by high resistance to pollution. However, the existing ban on the use of recycled polymer raw materials in the manufacture of food packaging limits the possibility of sales.

Thus, the most rational option today seems to be the construction of an industrial complex for processing waste polyethylene, polypropylene and PET into granulate.

This production must include:

a) sorting (requires special education personnel to reduce the share of another type of polymer, which is very important for the quality of the product);

b) washing (the largest potential volumes of raw materials are usually not sorted and washed);

c) drying, crushing, agglomeration.

It is economically most profitable to locate this complex in the near Moscow region, since prices for electricity, water, rent of land and industrial space there are significantly lower than in the capital (see Table 2).

For such production to operate effectively, government support is required. It might make sense to partially revise existing sanitary standards processing of solid waste, as well as oblige manufacturers of polymer products to make contributions for the processing of polymer waste. In addition, comprehensive measures should be taken at the level of the Moscow government and individual housing and communal services aimed at developing a selective collection system and creating a network of collection points for recyclable materials.

The state's increased interest in waste disposal is already reflected in the budget: from 2002 to 2010. It is planned to spend 519.2 million rubles for these purposes. from federal budget. The budgets of the federal subjects are expected to be allocated until 2010. 11.4 billion rubles. for the implementation of the “Diversions” program.

In 2001, Moscow spent on security environment 3.1 billion rubles To date, the cost of already implemented projects for processing household waste is 115.5 million rubles.

Andrey Golinei,

Equipment for processing plastic (polymers) is special machines and additional devices combined into a production line, which is used for processing or processing polymers (plastics) into useful and valuable materials for further use in construction, textile, chemical, oil and other industries .

Classification of plastic processing equipment

Depending on the functional features and purpose, all equipment for plastic processing is divided into:

1. Equipment for storage and dosing of materials/raw materials. As a rule, these are bunkers with devices for sorting (filtration) and unloading materials/raw materials.
2. Devices for transportation. They are either vacuum or pneumatic.
3. Machines for crushing and breaking - crushers, runners, shredders, pulpers, cavitators and others.
4. Faucets. Used for mechanical separation of substances through mutual movement of particles.
5. Roller machines. Necessary for the formation (creation) of fracture and crushing of polymer compositions.
6. Extrusion equipment. With its help, polymer materials are processed into various products by continuously pressing molten raw materials through a forming head, geometric shape which determines the profile of the final product.
7. Molding machines. This is polymer processing equipment used to make plastic compositions from powdered or granular raw materials, which are moved or compressed in the forming cavity of an injection mold, where it hardens and, after cooling, is removed.
8. Extrusion blow molding machines. They, according to the method of forming a product from a blank, are divided into blowing, extrusion and injection molding mechanisms.
9. Vulcanizing machines and presses. They are continuous or periodic and are used to create products from powdered or granular raw materials.
10. Applying and impregnating machines. They are used for applying polymer coatings to a special substrate.
11. Washing complexes. Necessary for preliminary purification of the polymer after granulation or grinding, but before its processing.

Plastic recycling machines

The following units are considered the main machines from a large number of varieties of special equipment for processing polymers:

• crushers - the unit operates on the principle of a blender, cutting whole products into small pieces;
• agglomerators - in which small pieces of polymer are further crushed and then sintered into small lumps;
• granulators - with their help, the mixture obtained from the agglomerator is heated and cut into granules.

Less important, but still necessary, is the following plastic processing equipment:

• washing line units;
• transportation hubs;
• different types separators;
• dryers.

Equipment for starting a mini-factory

To run a small plastic recycling plant, the following polymer processing equipment is required.

1. Basic equipment:
   • crusher or shredder;
   • agglomerator;
   • if necessary, a granulator.
2. Optional equipment:
   • hot wash tub;
   • 1-2 centrifuges;
   • extruders for recycling;
   • screen substitutes;
   • mixers and dispensers;
   • flotation washing;
   • connecting units (pneumatic or vacuum transport).
   • control module.

Major manufacturers of units for polymer processing

The most popular manufacturers of equipment for plastic processing are the following companies:

European.

1. HGMA Wulf GmbH is a German manufacturer with an excellent reputation, which produces not only equipment for primary and secondary processing of polymers, but also earthmoving and construction equipment.
2. Global Tech is a Polish company that makes fast and reliable stationary and mobile crushers.
3. Herbold Meckesheim is an excellent German manufacturer of units for the entire plastics processing and processing cycle.

Chinese.

1. China IS-MAC Machinery is the largest Chinese manufacturer of extrusion equipment for processing plastic bottles and other plastics.
2. LISHENG INDUSTRIAL is a manufacturer of washers, crushers, printing machines and other equipment.
3. Blue Ocean - manufactures extrusion machines and casting plants.

Russian.

1. GC Polymer System Group (Novosibirsk) - produces everything necessary for processing polymers.
2. ENGEL Austria GmbH (Moscow) – makes thermoplastic machines for plastic injection molding, units for processing rubber/silicone, etc.
3. StankoPet (Moscow) - produces almost the entire range of equipment for plastic processing.

Profitability of equipment for polymer processing

An approximate estimate for equipping a small polymer processing plant will include costs for:

• purchase of a line of equipment for processing plastic bottles - about $10,000;
• transportation and installation of equipment – ​​up to 15% of the cost of the equipment ($1,500);
• wages to employees - about $7,000;
• rental (+ renovation) of premises – $10,000;
• other events – $5,000.

At the same time, a ton of recycled plastic costs about $750, while the purchase of raw materials will cost $100 per ton.
The specified level of investment is designed for a mini-plant with the purchase of equipment for processing plastic bottles and similar polymer products with a productivity of 1 ton per day, i.e. with an income of $7,000 to $9,000 per month. With such a payback, the plant will begin to generate net profit in the second year of its operation (in 15-20 months).

It should be clarified that the payback period, as well as the costs of opening a plant, may be less if:

• preferences will be received from the state;
• the plant will be opened near the place where plastic is sorted for subsequent processing;
• The plant will receive gratuitous investments from international funds for environmental protection.

Receipt of raw materials and their sales

Depending on the production line and the wishes of the owner, a plastics processing plant can produce granular or powdered polymer raw materials. Marketing such products, as a rule, is not difficult, since they are in great and constant demand in the following areas:

• production of nonwoven materials;
• manufacturing building materials;
• production of polymer products for national use;
• production of chemical fibers;
• as an additive to primary raw materials (reduces cost).

Factories with corresponding production lines are widely represented in all regions and are in dire need of cheap raw materials.

In addition, the polymer processing line can be extended with additional equipment and some types of plastic products can be independently produced. For example:

• packaging nets for vegetables and fruits;
• garbage bags;
• packages;
• furniture fittings;
• polymer tiles;
• various pipes, shapes, parts for plumbing or sewerage;
• accessories or technical parts for cars;
• liquid storage containers;
• other small polymer products.

The 20th century is considered the century of steel and non-ferrous metals. Aluminum, copper, iron alloys could be found everywhere - in bed headboards, bridges, mechanisms of all types, and facing panels. However, as a result of mechanical processing, 50–80% of the melted material went into chips. Experts pinned great hopes on the chemical industry for reducing material consumption. And yet, despite the increase in the use of polymers, the results of industrial activity by the 80s were approximately the same: half of the resources were wasted.

Obviously, the apparent availability of polymers is an illusion. The raw materials used for their production are a natural rarity. Access to its sources is a daily and constant reason and reason for trade, diplomatic and other wars. The geography of natural resource extraction is increasingly shifting to places that are not so remote. Therefore, today they are increasingly talking about the need to introduce resource-saving business models.

The uniqueness of modern technological methods chemical production lies not only in the ability to synthesize materials that successfully replace metal, paper or wood.

Most of today's industrial complexes in developed economies are capable of recycling obsolete polymer products into new ones that are in demand by the user.

Recycled plastics

The main classes of polymers include:

• polyethylenes,
• polypropylenes,
• polyvinyl chlorides,
• polystyrenes (including copolymers - ABS plastics),
• polyamides,
• polyethylene terephthalate.

Products with complex compositions are first separated. For physical cleaning, various mechanisms are used - vacuum, thermal, cryogenic.

The most common and economically feasible technologies are flotation and dissolution.

In the first case, the plastic is crushed and immersed in water. Compounds are also added there that affect the ability of various plastics to absorb moisture. After separation, separated polymers are obtained.

In the second method, complex pressed parts are crushed and successively exposed to various solvents. To restore materials to pure form, the resulting compounds are exposed to water vapor. As a result of a precisely executed process, finished products of a high degree of purity are obtained. Further processing of various plastics may have its own characteristics associated with the individual properties of the polymers.

High and low pressure polyethylene (LDPE and HDPE).

A group of these compounds is also called polyolefins. They have found wide application in all types of industry, medicine, and the agricultural sector. PE are thermoplastics – materials suitable for remelting. This feature is successfully used by the industry, processing its own technological waste in order to reduce operating costs.

The difficulty of reusing used plastic is due to the partial destruction of its surfaces caused by sunlight. Products obtained through conventional processing of products: grinding, mechanical cleaning, remelting are not of high quality. Most often, such polyethylene is used for the manufacture of auxiliary household equipment.

Recycled polyethylene that has undergone chemical modification turns out to be more perfect. Various additives placed in the polymer melt bind the modified molecular units and align the structure of the substance. Dicumyl peroxide, wax, lignins, and shale are used as modifiers. Additives of certain types lead to changes in certain properties of secondary PE. Combining them allows you to obtain material with the necessary parameters.

Polypropylene (PP)

This material is rarely recycled. Most often, plastic has one life, despite its excellent consumer properties. characteristics that allow the polymer to be used in the food industry. Despite its good meltability, the high cost of maintaining hygiene discourages processors. However, in the United States, every fifth ton of PP is reused.

According to chemists, PP can withstand no more than four remeltings. With each heating, a certain number of deformed molecular units accumulate, affecting the physical characteristics of the material. Recycled granules are easily processed in extruders and injection molding machines.

Recycled plastic does not require special modification. Its parameters are comparable to the original material, with only slightly reduced frost resistance. The polymer is again finding application in battery housings, garden tools, containers and films.

Polyvinyl chloride PVC

The material is used for the manufacture of linoleum and finishing films. Plastic is subject to thermal destruction. At temperatures above 100°, the oxidation of macromolecules begins to accelerate, leading to a deterioration in the thermoplastic properties of the material.

Extrusion technology using recycled PVC requires special preparation: the initial raw material mixture in the melt may be heterogeneous. Solid modifications of PVC containing recycled plastic will have uneven internal stress. In order to minimize negative impacts, dry processing of granules in compactors is carried out before extrusion. As a result of this operation, fibers are formed that reinforce the walls of new products.

More often, recycled polyvinyl chloride is used to produce plastisols and vinyl plastics. These materials are used to produce pastes, solutions, and injection molded products. Among new technologies, multilayer casting is gaining popularity. The peculiarity of the method is the production of a multicomponent sheet, each layer of which has different characteristics.

The outer surface of the composite is formed by a high-quality polymer, the inner layers are formed by recycled plastic.

Polystyrene (UPS, PSM) ABS plastic

Different kinds polystyrene is recycled in one mass - impact-resistant modifications, copolymers, acrylonitrile butadiene styrene. The versatility of PS products is often the reason why industrialists refuse to process it. The cost of cleaning, sorting, and modification is too high.

Prospects for plastic recycling.

In developed economies, the share of plastics processing reaches 26% of the amount produced – up to 90 million tons. At the same time, the volume The global market is $600 billion. The domestic segment of polymer recycling looks somewhat more modest: 5.5 million tons. According to experts, the Russian industry's demand for monomers and full-fledged modified thermoplastics significantly exceeds their supply. The presence of these two factors leads to an increase in national capacities intended for polymer processing. Moreover, the growth rate of industrial volumes in this area is ahead of European ones. Current market trends are taken into account in government forecasts. The priority of re-equipment of the processing industry is included in the twenty-year industry plan for the development of gas and petrochemicals.

Waste is generated during the processing of polymers and the manufacture of products from them - this is technological waste, partially returned to the process. What remains after using plastic products - various films (greenhouse, construction, etc.), containers, household and large-scale packaging - is household and industrial waste.

Technological waste is subjected to thermal effects in the melt, and then during crushing and agglomeration - also to intense mechanical stress. In the polymer mass, processes of thermal and mechanical destruction occur intensively with the loss of a number of physical and mechanical properties and, with repeated processing, can negatively affect the properties of the product. Thus, when returning to the main process, as usual, 10-30 percent of secondary waste, a noticeable amount of material goes through up to 5 cycles of extrusion and crushing.

Household and industrial waste is not only processed several times at high temperatures, but is also exposed to prolonged exposure to direct sunlight, oxygen and air moisture. Greenhouse films can also come into contact with toxic chemicals, pesticides, and iron ions, which contribute to the destruction of the polymer. As a result, the polymer mass accumulates a large number of active compounds that accelerate the breakdown of polymer chains. The approach to recycling such different wastes should accordingly be different, taking into account the background of the polymer. But first, let's look at ways to reduce the volume of waste generated.

Reducing the amount of process waste

The amount of process waste, primarily start-up waste, can be reduced by using thermal stabilizers before stopping the extruder or injection molding unit, in the form of a so-called stop concentrate, which many people forget or neglect. When equipment stops for simple material in the extruder or injection molding machine cylinder, it is quite for a long time is under the influence high temperature when cooling and then heating the cylinder. During this time, the processes of crosslinking, decomposition and burning of the polymer actively occur in the cylinder, products accumulate, which, after start-up, come out for a long time in the form of gels and colored inclusions (burnt marks). Thermal stabilizers prevent these processes, thereby facilitating and speeding up cleaning of equipment after startup. To do this, before stopping, 1-2 percent of stop concentrate is injected into the machine cylinder for 15-45 minutes. before stopping at the rate of displacement of 5-7 cylinder volumes.

Processing (extrusion) additives, which increase the manufacturability of the process, can also reduce the amount of waste. By their nature, these additives, for example, Dynamar from Dyneon, Viton from DuPont, are derivatives of fluororubbers. They are poorly compatible with basic polymers and in places of greatest shear forces (dies, sprues, etc.) they are deposited from the melt onto the metal surface, creating on it a wall lubricating layer along which the melt slides during molding. The use of a processing additive in the smallest quantities (400-600 ppm) makes it possible to solve numerous technological problems - reduce torque and pressure on the extruder head, increase productivity while reducing energy costs, eliminate defects in appearance and reduce the temperature of extrusion of polymers and compositions that are sensitive to high temperatures. temperatures, increase the smoothness of products, produce thinner films. When producing large-sized or thin-walled injection molded products with complex shapes, the use of an additive can improve flowability, remove surface defects, weld lines and improve the appearance of the product. All this in itself reduces the marriage rate, i.e. amount of waste. In addition, the processing additive reduces the adhesion of carbon deposits on the die, fouling of the gates, and has a washing effect, i.e. reduces the number of stops to clean equipment, which means the amount of startup waste.

The use of cleaning concentrates has an additional effect. They are used when cleaning casting and film equipment to quickly change from color to color without stopping, most often in a 1:1-1:3 ratio with the polymer. This reduces the amount of waste and time spent changing colors. The composition of cleaning concentrates produced by many domestic (including Klinol, Cleanstayre from NPF Bars-2, Lastik from Stalker LLC) and foreign manufacturers (for example, Shulman - Polyklin "), usually include soft mineral fillers and surfactant detergent additives.

Reducing the amount of household and industrial waste.

There are various ways to reduce the amount of waste by increasing the service life of products, primarily films, through the use of thermal and light-stabilizing additives. By extending the service life of the greenhouse film from 1 to 3 seasons, the amount of waste to be disposed of is correspondingly reduced. To do this, it is enough to introduce small amounts of light stabilizers into the film, no more than half a percent. The costs of stabilization are low, and the effect when recycling films is significant.

The reverse way is to accelerate the decomposition of polymers by creating photo- and biodegradable materials that quickly degrade after use under the influence of sunlight and microorganisms. To obtain photodegradable films, comonomers with functional groups that promote photodestruction (vinyl ketones, carbon monoxide) are introduced into the polymer chain, or photocatalysts are introduced into the polymer as active fillers that promote the rupture of the polymer chain under the influence of sunlight. Dithiocarbamates, peroxides or oxides of transition metals (iron, nickel, cobalt, copper) are used as catalysts. The Institute of Water Chemistry of the National Academy of Sciences of Ukraine (V.N. Mishchenko) has developed experimental methods for the formation of nanosized cluster structures containing metal and oxide particles on the surface of titanium dioxide particles. The rate of film decomposition increases 10 times - from 100 to 8-10 hours.

The main directions for obtaining biodegradable polymers:
synthesis of polyesters based on hydroxycarbonic (lactic, butyric) or dicarboxylic acids, but so far they are much more expensive than traditional plastics;
plastics based on reproducible natural polymers (starch, cellulose, chitosan, protein), the raw material base of such polymers is, one might say, unlimited, but the technology and properties of the resulting polymers have not yet reached the level of basic large-scale polymers;
imparting biodegradability to industrial polymers (polyolefins primarily, as well as PET) by compounding.

The first two areas require large capital expenditures for the creation of new production facilities; the processing of such polymers will also require significant changes in technology. The simplest way is compounding. Biodegradable polymers are obtained by introducing biologically active fillers (starch, cellulose, wood flour) into the matrix. So, back in the 80s, V.I. Skripachev and V.I. Kuznetsov from ONPO Plastpolymer developed starch-filled films with accelerated aging. Unfortunately, the relevance of such material was purely theoretical at that time, and even now it is not widely used.

Recycling

You can give the polymer a second life with the help of special complex concentrates - recyclizers. Since the polymer undergoes thermal destruction at each stage of processing, photo-oxidative destruction during the operation of the product, mechanical destruction during grinding and agglomeration of waste, destruction products accumulate in the mass of the material, and contains a large number of active radicals, peroxide and carbonyl compounds that promote further decomposition and cross-linking of polymer chains. Therefore, the composition of such concentrates includes primary and secondary antioxidants, heat and light stabilizers of the phenolic and amine type, as well as phosphites or phosphonites that neutralize active radicals accumulated in the polymer and decompose peroxide compounds, as well as plasticizing and combining additives that improve the physical and mechanical properties properties of the secondary material and bring them more or less close to the level of the primary polymer.

Complex additives from Siba. The Siba company, Switzerland, offers a family of complex stabilizers for the processing of various polymers - LDPE, HDPE, PP: Recyclostab and Recyclossorb. They are tableted mixtures of various photo- and thermal stabilizers with a wide range of melting temperatures (50-180°C), suitable for introduction into processing equipment. The nature of the additives in Recyclostab is common for polymer processing - phenolic stabilizers, phosphites and processing stabilizers. The difference lies in the ratio of components and in the selection of the optimal composition in accordance with the specific task. “Recyclossorb” is used when light stabilization plays an important role, i.e. The resulting products are used outdoors. In this case, the proportion of light stabilizers is increased. The company's recommended input levels are 0.2-0.4 percent.

"Recyclostab 421" is specially designed for processing and thermal stabilization of waste LDPE films and mixtures with a high content of LDPE.

"Recyclostab 451" is designed for processing and thermal stabilization of waste PP and mixtures with high content.

"Recyclostab 811" and "Recyclossorb 550" are used to extend the service life of products made from recycled products used in sunlight, so they contain more light stabilizers.

Stabilizers are used in the production of injection molded or film products from recycled polymers: boxes, pallets, containers, pipes, films for non-critical purposes. They are produced in granular, non-dusting form, without a polymer base, pressed granules with a melting limit of 50-180°C.

Complex concentrates from the company "Bars-2". To process secondary polymers, NPF Bars-2 produces complex polymer-based concentrates containing, in addition to stabilizers, also combining and plasticizing additives. Complex concentrates “Revtol” - for polyolefins or “Revten” - for impact-resistant polystyrene, are introduced in an amount of 2-3 percent when processing recycled plastics and, thanks to a complex of special additives, prevent thermal-oxidative aging of secondary polymers. Concentrates facilitate their processing due to improved rheological characteristics of the melt (increased MFR), increase the strength characteristics of finished products (their ductility and resistance to cracking) compared to products made without their use, facilitate their processing as a result of increasing the manufacturability of the material (reduced torque and drive load). When processing mixtures of secondary polymers, “Revtol” or “Revten” improves their compatibility, so the physical and mechanical properties of the resulting products also increase. The use of Revten makes it possible to increase the properties of secondary UPM to the level of 80-90 percent of the properties of the original polystyrene, preventing the appearance of defects.

Nowadays, the development of a complex concentrate for processing recycled PET is very relevant. The main problem here is yellowing of the material, accumulation of acetaldehyde, and a decrease in melt viscosity. There are known additives from Western companies - Siby, Clarianta, which help overcome yellowing and improve the processability of the polymer. However, in the West and here we have a different approach to the use of recycled PET. If there 90 percent of it is used to produce polyester fibers or technical products and additives for this purpose are well developed, then our processors strive to return recycled PET to the main process - the production of preforms and bottles by casting and blow molding or the production of films and sheets by flat-slit extrusion. In this case, the target properties of the polymer that need to be influenced are somewhat different - manufacturability, moldability, transparency, and the formulation of complex additives must meet the goal.