We sell recycled crushed polyethylene. Secondary polyethylene granules - what is it, how are they produced, application. Special requirements for the premises

Why is it important to recycle polyethylene and why is polyethylene interesting for a recycling business?

Polyethylene is the most widely used of all types of plastics. It can be harvested in large quantities at a relatively low cost, and therefore a recycling business can use economies of scale to reduce costs and increase profits.

How much polyethylene is consumed and what products are made from it?

In Russia, the annual consumption of polyethylene is 1.6-1.7 million tons, a significant part of which is spent on products with short term services, feeding the waste stream.

What is polyethylene?

Polyethylene is a polymer, that is, a material consisting of very long molecules in which homogeneous groups of carbon and hydrogen atoms are connected in chains. Polyethylene has the simplest structure of all polymers. It has carbon atoms in the center of the chain, to which hydrogen atoms are attached.
The structure looks like this

In some places, instead of a hydrogen atom, a carbon atom is attached to the side of the chain, which also forms a chain or branch. Molecules can be branched to varying degrees, and the properties of the material strongly depend on this.

What raw material is polyethylene made from?

The very name of polyethylene suggests that it is a polymer of ethylene, that is, polymer chains consist of identical pieces, chemical formula of which C₂H₂ (ethylene). These constituents are called a monomer. In ethylene, each tetravalent carbon atom is bonded to two hydrogen atoms and to the adjacent carbon atom, with the latter having a double covalent bond. Therefore, ethylene is also called an unsaturated compound. Compounds with a double bond in chemistry are called olefins, hence the common name of polyethylene and some other polymers - polyolefins.
So, polyethylene is obtained by joining chains (polymerization) of ethylene molecules.
In this case, ethylene can be different sources, depending on which raw material is more accessible to petrochemists in each specific region and in each specific case. The main groups of raw materials are naphtha (derivative from oil refining), ethane isolated from natural gas or accompanying gas, and more and more now ethylene is being produced from ethyl alcohol, which can be obtained from many types of plant materials, including ethanol from sugar cane, which is now commercially used.

What are the properties of polyethylene?

The industry produces many grades of polyethylene, but they all differ mainly in only two parameters. This is the size of the molecules and the degree of their branching. These parameters do not depend on the feedstock from which ethylene is obtained, but depend on the conditions of the polymerization process, pressure in the reactor, temperature, presence and type of catalyst.
The first polyethylene in the industry learned to do with high pressure, in which the polymerization was initiated by free radicals. Such material is now called LDPE, it is characterized by high branching. That is, on each polymer chain there are many side branches, which in turn also have branches consisting of the same chains.
Later, with the help of catalysts, they learned to produce polyethylene at a lower pressure, it is called HDPE. Its molecules are much less branched.
To understand how the branching of molecules affects the properties of a polymer, imagine two panicles. One of them consists of smooth rods, without side branches. They are packed tightly and the panicle is so hard and strong. The other consists of rods with side branches. The density is already much less, and it is more pliable, flexible.
In the same way, HDPE, which is also called high-density polyethylene, and LDPE, called low-density polyethylene, differ. The first material is tougher, its strength is high. The second is plastic, products from it bend at lower loads.

Is it possible with a secondary processing of LDPE convert to PND and vice versa?

No, it’s impossible, the structure and sizes of molecules are set during synthesis, that is, at the plant where the primary polymer was produced, it is little subject to changes during secondary processing. However, it is possible to add rigidity to the LDPE material by adding a more rigid HDPE or other material to it, and it is also possible to add plasticity to the HDPE material by adding LDPE accordingly. This is often done in the manufacture of products from recycled polymers. Mix different types.

What determines the rheological properties of polyethylene, the melt yield strength?

on the size of the molecules. The larger and longer the molecules in a polymer, the less fluid it is. The fluidity of a polymer is measured under load and at elevated temperature.

What types of polyethylene raw materials are available for recycling?

Production waste and consumer waste are available.
Production wastes differ, in most cases, in purity and are homogeneous, however, each source contains a relatively small amount of them. It is understandable, because production facilities are not designed to produce waste. Often recycled industrial waste is a relatively uncomplicated process and those who form them are increasingly using them themselves after minimal processing, such as crushing or granulating on a small, simplified granulator.
Large in volume, but complex in composition, consumer waste, that is, waste of products or packaging that were in use. Recycling of such wastes is usually difficult, their processors must have a large amount of equipment, so economies of scale make enterprises for their processing relatively large. They collect waste from a variety of sources (garbage sorters and commercial sources).

What polyethylene consumer waste can be recycled?

In the existing market of secondary raw materials in Russia, the following types polyethylene waste:

1. Waste films from low-density polyethylene, including stretch films, collected by sorting from commercial sources - stores, are relatively clean, washing is not required to remove contamination, melt filtration in an extruder and degassing are sufficient.
2. Waste films collected from consumer waste require washing, as they are contaminated, among other things, with food waste.
3. Stretch - is assembled separately, it is most often a linear low-density polyethylene with additives.
4. Blown bottles for liquid products and goods - consist of HDPE, require washing and thorough degassing of the melt to remove product residues that are absorbed into the walls of the bottles. Abroad, milk bottles are usually collected separately, but this applies to those countries where a significant percentage of milk is packed in high-density polyethylene bottles.
5. Canisters can be of different quality depending on what was poured into them before. As mentioned above, the processing of oil cans is difficult due to oil residues.
6. multilayer films, most of which polyethylene makes up - the processing of such films presents technological difficulties, the description of which is beyond the scope of this article.
7. Waste cables - they often use cross-linked polyethylene, that is, one in which bridges between individual molecules were deliberately created. Its processing is difficult because the material does not flow at melting temperatures, but only softens. The percentage of gel there is very high.
8. Agricultural film - a film that has been used in agriculture. It can usually be severely damaged by photo-oxidative degradation.

Which products are made from which types of recycled materials?

Type of waste for recycling	Density	Melt yield strength	Products
Waste LDPE films collected from commercial sources	0,915 – 0,925	0,8 -4	New film, also for packaging
Waste, films collected from garbage sorting	0,915-0,945	0,6- 4	Granules for molded products
Stretch			Granules for mixing into other types of raw materials as a modifier
Blown bottles for household chemicals and food products	0,945 – 0,955	0,1- 0,8	Unloaded pipes, drainage pipes
canisters	0,945-0,955	0,1-0,8	Unloaded pipes, drainage pipes, Wood-plastic composites, geomembranes, sheets for other purposes.
Multilayer films			Non-responsible products, additives for other pellets
Waste cables and wires		0,1	Additive for other granules
Agricultural film	0,915-0,925	0,8-6	Granules for adding to new film and for molded products.

What methods of processing polyethylene are used?

There are two main processing methods, these are mechanical recycling, when the material is used as a polymer for the manufacture of products or other purposes, as well as thermo-chemical recycling, pyrolysis, which results in liquid and gaseous products of thermal degradation of the polymer. Next, we will talk about mechanical recycling.
What processes include the processing of polyethylene?
The main processes are sorting, grinding, washing, drying and agglomeration or granulation. Depending on the feedstock and productivity, the combination of these processes may be different, for example, grinding can be carried out both in one stage and in two stages. Also, if the raw material is collected from a relatively clean sources, the washing and drying step can sometimes be omitted.

What equipment is used for processing?

​Polyethylene waste that has been in contact with products is washed contaminated on the washing lines. As a rule, the washing line includes the following elements:

- Equipment for grinding and shaping particles. Shredders or crushers. The former are preferred in most cases, as they are more durable when hit by hard objects such as stones or metals, but shredders are more expensive than crushers. In crushers, the rotation speed of the rotor is higher, hitting a solid object can immediately disable the crusher, in especially severe cases it will be necessary to replace all the knives. But crushers are often made with a pre-cleaning function, for this they are supplied with water. On high-capacity lines, both a shredder and a crusher are used, that is, grinding is organized in two stages, between which equipment for separating heavy particles is necessarily placed to protect the crusher.

- Equipment for separating heavy particles such as sand, stones, metals and plastics incompatible with polyethylene, such as polyethylene terephthalate, which sinks in ordinary water.
Two types of equipment are used to separate heavy particles: flotation tanks and hydrocyclones. The latter are almost exclusively in high-capacity lines, such as 2 tons per hour.

- Equipment for intensive washing of plastic. For this purpose, friction washers and (or) centrifuges are used.

Pressing equipment - usually centrifuges and screw presses. After mechanical pressing, the moisture content of the films can be from 6 to 12 percent. This may be too much for efficient further agglomeration, so mechanical drying is often not limited.

- Equipment for thermal drying - they, as a rule, organize the movement of plastic particles along with the flow of heated air in labyrinths (long pipes or channels) of various designs. Sometimes in the lines the final drying is not done and it is left for the stage of agglomeration or granulation.

The work of agglomerators and plastcompactors is based on mechanical heating of the material and then its clumping, compaction using various technological methods.

The operation of the granulator is based on heating the material with electric heaters to melting temperatures, mixing the resulting melt and purifying it by filtering, pumping out gases formed during heating, and then forming granules by squeezing the melt through dies (matrices with holes) and cutting the resulting strands in one way or another. (water ring and strand granulators). The advantage of granulators over agglomerators and plast compactors is that they make it possible to obtain a more reliable product, since mechanical impurities that could remain after the washing line are filtered out on granulators and impurities of fats or other substances decomposing when heated can be removed by degassing the melt.

​More details about the equipment with examples of lines on the site http://moykaplastica.ru

What is polymer degradation?

Polymer molecules are inevitably damaged during recycling for three reasons. This is, firstly, a mechanical load, for example, in an extruder, when high blood pressure the material is mixed. Secondly, it is heat, which contributes to a more active movement of molecules and the bonds between atoms become not as strong as at ordinary temperatures. Thirdly, this is the action of atmospheric oxygen, which, being an active oxidizing agent, tends to oxidize the elements of the polymer chain, hydrogen and carbon. Thus, during recycling, polymer molecules change, some of them become shorter, torn apart. Every time a polymer chain breaks for one reason or another, a radical is formed, that is, an atom or a group of atoms whose valences are not closed, there is a vacancy on the external electron cloud. Such radicals are extremely active, they form compounds with neighboring molecules, while damage to the neighboring molecule forms a new radical, which in turn damages another chain. When the molecules are crosslinked by separate adhesions, the resulting structure is called a gel. The content of gels in secondary granules changes mechanical properties usually not the best
side.

Why are the properties of recycled polyethylene worse than those of primary?

Oxygen appears to be the main culprit for the reduction in properties. During destruction, it not only creates radicals, as described above, but it can also be incorporated into the material, replacing hydrogen and carbon atoms, and oxidize polyethylene. The presence of oxygen atoms in a material changes its properties. Initially, polyethylene is non-polar. This means that it only contains hydrogen and carbon atoms, which have a non-polar bond between themselves, because their electronegativity is quite close. That is, they are connected through common cloud electrons, which is more or less in the middle ( in simple words, is actually more difficult). But as soon as an oxygen atom appears nearby, the second most electronegative element after fluorine, then immediately oxygen affects all the bonds that are nearby. It polarizes them to some extent. Attracts electrons to itself. This reduces their strength under mechanical action reduces the resistance of neighboring bonds to other oxygen atoms, which also tend to snatch and oxidize something from the polymer molecule.
Hence, important practical knowledge is that the more polyethylene is oxidized (destructed), the faster it oxidizes further and its properties fall even faster. This explains more unsuccessful than successful experiments to improve the properties of recycled plastic by adding unspoiled primary. The secondary, if it has already destroyed, then quickly poisons the primary with its influence, and this is precisely because of oxygen and its magnetic activity in relation to electrons in molecules.

For example, following the link to an article by Swedish researcher Michael Hamskog (with whom I have worked before), the article concluded that blending virgin polyolefin with recycled polyolefin was inefficient and adding additives was more effective. which will be discussed below.
https://www.sciencedirect.com/scienc...41391005003629

How does the MFR of polyethylene change during recycling?

So the MFI can change both up and down, depending on which process develops more strongly, shortening or crosslinking, and this, in turn, depends on the processing conditions. Most often, there is a shortening of the molecules, that is, an increase in fluidity.

How to reduce polymer degradation during recycling?

In order to slow down the degradation, special substances are added to the polymer that can take on the resulting radicals and do not allow the process to develop according to a chain scenario, when damage to one polymer chain leads to damage to neighboring ones.
Unfortunately, these substances are consumable. That is, over time, their action weakens and they are already working out. Sometimes, in order to restore the dose of stabilizers, they are added to the polymer during recycling. For example, such a composition as Ricyclestab.
In order to minimize degradation, in general, it is necessary to minimize the mechanical and thermal loads on the polymer during recycling, that is, do not overheat it above what is necessary, do not use excessive mixing under pressure in the extruder.

How do polymer contaminants affect the properties of the recycled material?

When recycling end-of-life waste, contamination is always a major concern. They are acquired from contact with other substances, including the substance that was packaged in polyethylene packaging. Contaminants are either surface or internal.
So oil canisters contain some residual amount of these oils in the form surface contamination, but part of the oil is dissolved in the walls of the canister and during recycling, even if the material is well washed, an odor may appear, the properties of the secondary polymer may change due to plasticization of polyethylene with oil (partial dissolution of oil in polyethylene).
This is typical not only for such pronounced substances as butter and detergents, but also for ordinary milk. Bottles made of HDPE, which previously contained milk, even after washing, contain a certain amount of lactic acid in their walls, which has dissolved in polyethylene. Odor may occur during processing.
Other contaminants such as sand or earth, pieces of paper also reduce the mechanical properties of the polymer and must be removed.
To remove surface contaminants, washers are used in which the material is thoroughly washed with water in combination with some mechanical efforts (friction washers), and dry cleaning installations, for example, manufactured by MAS, can also be used, but the latter do not cope well with sticky contaminants even in cases where there are sticky ingredients.

How to recycle cross-linked polyethylene?

Cross-linked polyethylene is one in which links (bridges) are additionally made between individual macromolecules. This is usually done for those products that are used at elevated temperatures, such as electrical insulation. Such polyethylene can withstand somewhat higher than the melting point. So, for example, the cable insulation will not drain, but will only soften. In fact, cross-linked polyethylene is no longer a thermoplastic plastic. It does not melt, as it should, but softens, so recycle it in the usual way impossible.
There are two possible approaches to the processing of cross-linked polyethylene. First, it can be processed by thermal methods, such as pyrolysis, to produce liquid and gaseous products.
Secondly. Theoretically, cross-linked polyethylene can be ground to a particle size of less than 0.5 mm and used as an additive in conventional polyethylene products. The author worked on this idea for a long time and was already planning to test it in practice, but somehow his hands did not reach. The difficulty is that cross-linked polyethylene grinds very poorly, so it was not possible to obtain powder from it at a very low price. The estimated price was up to 10 rubles per kilogram. Second, it is not clear how cross-linked polyethylene will affect Melt Yield Strength. Apparently, it will reduce the MFR, but this needs to be checked.

Probably, big potential processing of cross-linked polyethylene lies in the development of new methods of its grinding. For example, if you use the natural cold in the Siberian part of the country, then you can probably get more productive process grinding in conventional mills than it was until now. At a sufficiently low cost, this material could compete in the filler market, because it has the same density as polyethylene, that is, there will be no increase in the density of granules or products, and it will probably affect the properties of the polymer to a lesser extent than if it is compared with mineral fillers. If you are interested in equipment for grinding cross-linked polyethylene, write to the contacts below.

How to start a polyethylene recycling project?

From establishing contacts. First of all, we need contacts with waste sorting stations and other sources of recycled polyethylene, then contacts with manufacturers of plastic products that are ready to consider proposals for the use of recycled polyethylene.
When there is an understanding of the available volume of raw materials and possible sales, you can begin to select equipment and, together with suppliers, design production line for processing.
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Information about advanced level processing equipment:

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​ For questions about the sale of polyethylene waste, films, bags, substandard products, call
​ +7 916 103 1486
or write mail.ru

Polyethylene recycling various types is important for the environment and industry, but we must not forget that the process of processing household and industrial polyethylene components is largely different (this is due to differences in technical specifications). Sometimes recyclable materials, namely polyethylene, may have some characteristics that do not correspond the right parameters. Quite significant is the fact that plasticization has an extremely positive effect on the growth of the quality of the material.

Features of polyethylene recycling

Polyethylene has a wide range of applications, which undoubtedly include its use as packaging. It is important to take into account the fact that the service life of such packaging is very long, as well as the impact on it of a variety of weather factors:

The effect of various temperatures, as well as their abrupt change;
- direct impact sun rays;
- gets contaminated.

A process such as the processing of polyethylene is not much different from the production of primary materials. But the change in the process still takes place, and therefore, the number of processing cycles is also excellent.

Polyethylene waste recycling technologies

Today, the most advanced method of processing polyethylene is the replacement of wooden materials with intermediate ones. During the process, a special degree of purification of secondary materials is required (as an example, containers from fuel and lubricants can be cited).

At the same time, it is very popular to use secondary materials for the manufacture of various containers. They are made either completely from recycled materials, or source material is added during the manufacturing process. Such containers are very actively used by a variety of companies.

An alternative method of processing polyethylene components, which is based on the use of irrigation pipes, is also very actively used. The diameter of such pipes can exceed 600 mm. Recycling of polyethylene can be carried out by the application method. An important factor is that the quality of the resulting material becomes lower. But such materials are also in demand, for example, panels for garbage cans are made from them.

Equipment for polyethylene processing

Recycled materials must be processed into granules, it is optimal to use agglomerates for this. This is a special one, which consists of several modules. It should be noted that in order to work with plastic bottles you can connect the appropriate module, which will wash and crush them.

Polyethylene recycling is carried out on equipment that has a number of advantages that simplify the fluid workflow:

Very high performance and economy, very well combined with small dimensions;
- the opening for loading is located at a sufficiently low level, which makes it possible to do without auxiliary devices (ladders, platforms, etc.);
- equipped with an easily removable housing, which increases the convenience in repair and maintenance;

Aerodynamic swirlers make it possible to process even the smallest and thinnest secondary materials;
- all vital components and mechanisms are perfectly protected from the ingress of the working mass, as well as dust and dirt;
- Reliable insulation against moisture.

Using recycled polyethylene materials for the production of new household and industrial products is more efficient than using only virgin raw materials. Products from recycled polyethylene product, which are the result of processing polyethylene, are much cheaper than products from virgin materials.

The neglect of polyethylene waste is dangerous for the ecological situation. Recycling polyethylene into granules allows you to give it a new life, because many useful goods can be made from this raw material.

Limit the production of packaging products made of polyethylene in modern world quite difficult, but competent waste management solves the problem. Polyethylene raw materials are highly recyclable, modern technology recycling is environmentally friendly and does not require significant costs of natural resources.

Why is it important to recycle waste instead of throwing it in landfills?

1. In natural natural environment polyethylene decomposes for more than 300 years, releasing toxic substances into the soil and water.
2. Recycling allows you to use raw materials rationally, produce the necessary goods from recycled polyethylene cheaper, and save resources.
3. Recycling practically does not affect the quality of the material, secondary polyethylene is almost the same in properties as the primary one.

Stages of processing

1. Collection of raw materials.
2. Sorting, separation from household waste.
3. Cleaning - polyethylene must be washed from contaminants in special washing machines.
4. Grinding - in special crushers, the material is crushed.
5. Processing in a centrifuge relieves raw materials of residual impurities and excess moisture.
6. Drying - polyethylene undergoes heat treatment in special drying chambers.
7. Agglomeration - on special equipment under temperature and pressure, as well as using catalysts, raw materials are melted and sintered into granules.

Polyethylene granulation

1. Bulk material enters the granulator, several heating cycles clean it from impurities (garbage, metal, water, air inclusions).
2. At a temperature of 200°C, the molten polyethylene mass is passed through the forming holes (dies), from where the molten polymer flows out in thin streams.
3. Raw materials are cut with knives and cooled with cold water.
4. Collection of the product in the storage hopper and packaging in containers.

Necessary equipment

The line for recycling polyethylene waste includes:

• washing machine;
• crusher;
• drying plant;
• centrifuge;
• agglomerator;
• granulator;
• extruder.

For automatic supply of raw materials to the line, a conveyor or pneumatic conveyor is used. Processing of polyethylene into granules takes place directly in the agglomerator. With the help of special machines, finished products are formed. Granulation equipment is not always part of the production line.

Granular polyethylene can be of different quality, it is divided into 3 grades:

• Higher - made from unpainted packaging films, according to the characteristics of such granules are universal, suitable for the production of cast products and secondary film;
• 1st - physical characteristics are similar to the highest grade, the basis for the production of granules is dyed in light colors packaging material;
• 2nd - made from sorted dark-colored raw materials (black, gray), then building materials and household goods are made from recycled granules.

Application

From recycled polyethylene you can get:

1. New bottles for bottling drinks.
2. Disposable container.
3. Packaging films and bags.

Recycled polyethylene can become the basis for the production of building materials:

• finishing and decorative tiles;
• heat and waterproofing;
• sanitary communications (pressure pipes, drainage systems);
• decorative fences and pool accessories.

The use of pellets for the production of useful goods can be much wider. The technology is constantly being improved, specialists are looking for new areas of application for recycled polyethylene.

Recycling polyethylene waste into pellets is very profitable. Residents of large cities, handing over raw materials to special items reception, can contribute to the improvement of the ecological situation. As a result, production receives inexpensive raw materials, which makes it possible to produce high-quality goods at more affordable prices. In the recycling process, the main difficulty is to establish a regular collection and delivery of raw materials to the site. A civilized way of waste disposal helps relieve public landfills and improve the quality of life for people in megacities.

Removal, processing and disposal of waste from 1 to 5 hazard class

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Why is neglect of containers dangerous and how important is polyethylene recycling for the environment? In our life, polyethylene is present as a packaging container, but despite its narrow specialization, it is widespread everywhere. Almost every house has a package with packages that we collect from the principles of economy. But the trouble is, it turns out that the better the raw material, the more difficult it is to dispose of it and the longer the period of its decomposition itself.

The relevance of processing

Recycling of polyethylene raw materials is an important cost item for the city, as the material is characterized by incredible stability. He is not afraid of water, alkali, salt solutions. Polyethylene is not afraid even of organic and inorganic acids. It can be noted that these are good qualities, but they can turn into a number of problems.

First of all, the ecological situation causes concern - according to approximate estimates, the decomposition of polyethylene takes up to 300 years. If simple plastic bag ends up in a landfill total mass household waste, it greatly complicates the processing process. Over time, this package undergoes thermal aging, gradually decomposing under the influence of sunlight, heat and oxygen. In the course of destruction, a harmless package releases harmful chemical substances into soil and water.

Alas, it is not possible to limit the production of plastics and polyethylene, but it is possible to rationally organize the entire workflow. Waste polyethylene, in fact, is a versatile material. Recycling of polyethylene, without exaggeration, can be called new life raw materials. Man is required to create and improve ways to collect and process raw materials in order to make the process cyclical. Polyethylene waste may well become everyday items.

Processing companies

AT last years the number of organizations processing this raw material is steadily growing. And it's not just about environmental issues but also in the prospects for the development of such a business. Polyethylene can be an excellent base for creating plastic panels, garbage containers, all kinds of household containers. There is a certain scope for the imagination of entrepreneurs, although, of course, secondary polyethylene products involve some limitations.

Difficulties recycling It does not cause films and bags, since the structure of the materials used does not change for the most part, but the quality of the processed raw materials decreases, and the scope of further application narrows accordingly.

Workflow features

There are several cycles of processing plastic bags, films. The first cycle has almost no effect on the decrease in consumer characteristics of new products. But each subsequent cycle makes its own “negative contribution”, making raw materials suitable only for the production of special materials.

According to existing technologies, six stages of polyethylene waste processing can be distinguished:

1. First comes the collection of raw materials: films, bottles, other household waste. Waste sorting can be done by manual or mechanical labor. If household waste during collection is divided into waste paper, glass, paper, PET, then it is possible to reduce the amount of garbage that needs to be disposed of by a third.
2. The collected raw materials are sent to washing machines. This stage is necessary in order to get rid of dirt, foreign objects and paper. If raw materials are delivered directly to collection points, then the receiver can check the condition of the film, bottles, waste paper in order to increase or decrease the price offered for them.
3. Next, the collected raw materials are crushed, for which crushing plants are used.
4. In case moisture or random solid impurities remain in the raw material, the centrifuge process is carried out.
5. Now the material is sent to the drying chamber, where heat treatment also takes place.
6. The work is completed and the material is ready for recycling. From it you can make universal products: polyethylene film, bags, packing containers, pipes.

Work in detail

And now let's try to take a closer look at the process of processing polyethylene into granules, because before that the process was considered only schematically. Of course, the right equipment is required for the job.

Well-established work is possible with:

• washing machine
• crushing plant
• centrifuges
• drying plant
• agglomerator
• granulator
• extruder

In production, the presence of a conveyor or pneumatic conveyor will be relevant, which will allow the process to be fully automated.

At home, it is almost impossible to establish an uninterrupted process for obtaining recycled polyethylene, but you can lay the foundation for promising business. First of all, you can declare the process of collecting raw materials, since without it such work is in principle impossible. Manual sorting of household waste will cost less than mechanical sorting, but you will have to start with a small amount of raw materials used.

Self-processing of the film allows you to get a dense waterproof fabric with a waterproofing function. The work process itself is simple - a piece of film must be laid between two parts of the fabric and ironed with an electric iron. The output is a three-layer composite material, as the film melts and penetrates into the layers of the fabric. With your own hands, you can get a composite material based on film, fabric and aluminum foil. The algorithm of operation is the same except for the fact that one layer of fabric is replaced by foil. Film, fabric and foil material is an excellent heat insulator. With the help of cross-linked polyethylene, many people equip a warm floor in the house.

For more benefit

Agglomerator - a device capable of processing film and bottles. Due to the temperature effect, an agglomerate is obtained - baked lumps from former bottles and films. The agglomerate can be sold already at this stage or go further and process it into pellets.

The polyethylene granulator allows you to increase the company's income from the collection and sale of secondary raw materials. The result is a product that technically outperforms its “powdery or flake counterparts in the shop” due to its small volume (and, accordingly, lower packaging and transportation costs), high flowability, minimization of losses and dust formation, lower risk of destruction and photoaging.

Why does an enterprise need an extruder? Just with its help you can get a unique material - polyethylene low pressure. The extruder starts working after the agglomerator has his say and turns the result of collection and processing into slurry. Now the molten mass of plastic goes through the forming hole, where it melts and creates threads that cool under water and are cut into small pieces. At the output, a HDPE granule is ready.

At low pressure

Low density polyethylene is widely used all over the world. It is an organic compound that resembles white wax. Recycled polyethylene low pressure is obtained through the collection and recycling of bottles and pipes.

This material is not afraid of frost or chemicals. It does not feel shock and is not a current conductor. It should be added that this material is waterproof and does not react with alkalis, acids and salt solutions. HDPE decomposes under the action of nitric acid (50%), chlorine and fluorine.

How this product can be useful

1. Based on HDPE, accessories for swimming pools are made.
2. It is used in the process of 3D printers.
3. Such material is actual for work in the conditions of chemical and electric influence.
4. HDPE is good for creating anti-corrosion coating, food containers, bottles and collecting water connections.
5. In sports facilities, HDPE is used for the production of gymnastic hoops.
6. In restaurants, HDPE is a future plastic bag, plastic set or container. The HDPE bag rustles and wrinkles, so it is used for the so-called "T-shirts".
7. Pyrotechnics makers use HDPE to make their work more spectacular.

Outcome

The processing of polyethylene raw materials into granules makes it possible to significantly reduce the amount of garbage in urban landfills. Remember that polyethylene and plastic almost do not decompose. Meanwhile, on the basis of PET, you can make successful business. Don't throw away things that might come in handy later. Even a simple package, bottle, film - can be useful for business.

Polyethylene is the most widely used polymeric material in the world with a share of about 39% of the global production of thermoplastics. Closest Competitor, polypropylene, takes only 24%. In this article, we will consider the most common methods for processing polyethylene and their technological features.

Recycling of virgin polyethylene

The primary is called polyethylene, synthesized in production by polymerization of ethylene. Most often, these are milky-white granular raw materials (if the brand has not been dyed). Here are the most common ways to recycle polyethylene:

• Extrusion. More than 70% of polyethylene in Russia is processed by the extrusion method, as it is very versatile. The essence of the method is to supply the polymer melt to the extruder head under pressure. In this case, the head may different shape, and, passing through it, the polymer acquires the desired shape. First of all, PE of "pipe" and "film" grades is processed in this way to produce the corresponding products. In addition, cable insulation and PE sheets of various thicknesses are produced by extrusion.
• Rotational formation. The method is used for the manufacture of various hollow containers made of PE: from small food containers to large containers with a volume of up to 10 thousand liters. The essence of the method is to load the required amount of polyethylene granules of a brand applicable for rotational molding into a special mold, which is simultaneously heated and rotated in several axes. As a result, a melt is formed inside, which evenly covers the walls of the mold and makes it possible to obtain a product with different wall thicknesses.
• Injection molding. The technology is suitable for the manufacture of products for various purposes, most often from HDPE grades. The essence of the method lies in the supply of a polyethylene melt into a mold of the desired geometry under pressure. Injection grades are distinguished by increased melt fluidity, which allows the polymer to accurately repeat the shape outlines and achieve the correct geometry of the finished product.

Recycling of recycled polyethylene

Considering Negative influence PE waste on the environment, the issue of processing waste raw materials and its reuse is very relevant. Almost any PE waste goes through the following algorithm:

• Sorting. The polymer is separated from other waste on semi-automatic lines: part of the work is done by people manually, partly the mechanical mixture of waste is sorted by machines.
• Washing and cleaning. In order for polyethylene to be recycled, it must be cleaned of impurities as much as possible, for which it is washed under streams of water and steam.
• Grinding in crushers and filtration with a centrifuge. The material is finally cleared of impurities.
• Another wash and dry. After the crushed mixture is dried again, the secondary raw material can be considered ready for further processing.

For secondary raw materials, the most commonly used method is extrusion and injection molding. At the same time, not all types of products can be made from recycled PE, since the technological properties of the material after such processing still deteriorate significantly.