6 RECYCLABLE PLASTIC MATERIALS MOST USED IN THE INDUSTRY

13 MAR 6 RECYCLABLE PLASTIC MATERIALS MOST USED IN THE INDUSTRY

Oil refining originates naphtha, an essential material for plastic production, whose carbon and hydrogen molecules undergo a chemical division called cracking, which forms monomers such as ethylene and propylene.
In the polymerization process, new chemical reactions group and order these monomers to form the polymer, long and complex molecular chains, responsible for changing the properties of the plastic, related to size, structure, composition and molecular interactions.
These variations form the two categories of plastic, thermosets — non-recyclable plastics — and thermoplastics, widely used in industry because of their applicability and possibility of reuse and recycling, mainly in post-consumer use.
Recyclable plastic materials have characteristics similar to virgin material: they are waterproof, malleable and durable, they also have other differentials, as they provide better cost-effectiveness in industrial production and sustainability in environmental management.
In this post, we will discuss a little more about recyclable plastic materials and what are the main types of plastics resulting from recycling processes used in the industrial sector. Check out!

CLASSIFICATION OF PLASTICS

THERMOFIXES

Rigid material, which does not undergo chemical changes under heat and pressure and, therefore, cannot be remodeled after cooling, not undergoing new processing cycles.
Thermosets are polyurethanes (PU), ethylene vinyl polyacetate (EVA), polyesters and phenolic resins (snooker balls, adhesives, paints) among others.
Most thermosetting compounds are used in products with high technical demand, specific, durable goods (car or aircraft parts) and/or are obsolete and, therefore, more than 90% of resins found in the market are thermoplastics.
There are also materials that hinder the recycling process:

  • food packaging containers that contain difficult-to-remove contaminants such as grease;
  • casings used for packaging toxic products;
  • foam, cellophane, disposable diaper, adhesive;
  • bakelite — radio and telephone parts, pan cord, switches, sockets;
  • metallized packaging;
  • acrylic cups.

Even if the consumption of these types of plastics is less than 10%, the ideal is to avoid their use and dispose of them with creativity, by reusing them in other functions or encouraging the reuse of their parts.
Some companies have plastic collection programs that are difficult to recycle, placing them back in the production chain, in order to avoid sending them to landfills and dumps.

THERMOPLASTICS

The main thermoplastics (according to applicability and consumed volume):

  • polyethylenes (HDPE, LDPE, LDPE, LLDPE, ETC.);
  • polyvinyl chloride — PVC;
  • polyethylene terephthalate — PET;
  • polypropylene (PP);
  • polyamides (PA);
  • polystyrene (PS);
  • acrylonitrile butadiene styrene (ABS);
  • polycarbonate (PC);
  • polybutadiene terephthalate; (PBT).

High performance compounds, for more commercial use, with better technical conditions and properties (processes, costs, etc.). When heated, they soften and therefore can be remolded.
They cover several types of plastic used in packaging of food, beverages, beauty and cleaning products, lids, toys, cups, grocery bags and various bottles.

PLASTICS THAT CAN BE RECYCLED

Plastics that can be recycled are represented by a triangle formed by three arrows with an identification number for classification in the center.
Although it is not mandatory to use this symbology on the surface of packaging or parts, this number facilitates the recycling process, as it helps to separate the material for the formation of flakes (flakes resulting from reprocessing and reused in industry).
According to the Brazilian Plastic Material Transformation and Recycling Industry (Abiplast), 269 million tons of thermoplastic resins are produced worldwide per year.
In Brazil, the main resins are consumed in the following proportion:

  • PP — 22.3%;
  • PVC — 15.6%;
  • HDPE — 17.4%;
  • LDPE — 10.6%;
  • LLDPE — 12.4%;
  • PET — 7.1%;
  • PS — 4.6%;
  • EPS — 2.3%;
  • EVA — 1.4%.

Check out, below, some examples of these plastic materials in which it is possible to carry out the recycling process.

1. POLYETHYLENE (PE)

Produced with different densities, it is one of the types of plastics most used in the industry in food packaging, tubes for cables and wires, ropes and fibers for carpets (also used PET), beverage bottles and boxes, in the composition of waterproof vests. bullets and fiber optics. They are resistant to many acids and alkaline solutions and can be classified into:

Low Density Polyethylene (LDPE)

Represented by the number 4, it is soft, easy to bend, more flexible, light, transparent, waterproof and can be processed by blowing, extrusion or injection.
It is widely used in packaging such as supermarket bags, milk and yoghurt packaging, household items, toys, tube and hose linings, garbage bags, textile packaging, food, agricultural, pharmaceutical and hospital packaging.

High Density Polyethylene (HDPE)

Represented by the number 2, the high density polyethylene it is light, non-toxic, unbreakable, rigid and mechanically and chemically resistant, being one of the most used due to its cost-effectiveness.
It is used in product packaging such as detergents, fabric softener, food storage jars and wrappings, in the manufacture of pyrotechnic articles, plastic pallets, geomembranes in landfill linings and in the composition of plastic wood.
Its industrial use is in oil containers, transport boxes, chemical products and paint drums, but it is also found in the hospital and civil construction sectors.

Linear Low Density Polyethylene (LDPE)

With high sealing capacity at high temperatures, it has physical properties of rigidity, density and resistance. It is used in food packaging, industrial films, sanitary napkins, disposable diapers, tarpaulins, toys, pharmaceutical and hospital products.
When processed by extrusion, it can be used in poultry, bread and bubble wrap packaging. When mixed with HDPE or LDPE, it composes the material used to create industrial sacks (packaging for animal feed, agricultural film, etc.).

Ultra-high molecular weight polyethylene (PEUAPM)

It comes in powder form, which polymerization is carried out in one or more steps, with a hydrocarbon solvent, to subsequently undergo pressing, compression or piston extrusion processes and used in the food, chemical, pharmaceutical, paper and cellulose industry. and mining.
It is resistant to abrasion, cyclic fatigue, corrosion, impact and chemical inertness. It can be made up of coatings, mixers, scrapers, bearings and tubes, pumps, valves, rulers, profiles, wear guides, track rollers, among others.

Ultra-low-density polyethylene (LEUBD)

This type of plastic is more resistant, flexible and has better optical properties compared to linear low-density polyethylene, widely applied as a modifying resin to increase the flexibility and resistance of HDPE, LDPE and polypropylene (PP).

Medium Density Polyethylene (LDPE)

Obtained by mechanically mixing LDPE and HDPE, it has intermediate properties. Used in pipes for water and gas distribution system in engineering projects.

2. POLYETHYLENE THEREPTALATE (PET)

Represented by the number 1, they are unbreakable, resistant to low temperatures, lightweight, waterproof and rigid. Its application preference is due to its chemical and mechanical resistance, shine and transparency, which also allows it to offer safety and protection to the food products involved.
Some packages made with this type of plastic have easy opening and closing systems, which are also very efficient for food maintenance.
The food and beverage industry, in recent years, has been replacing glass and aluminum packaging of its products with PET plastic, due to its resistance, cost and recycling made possible on a large scale by cooperatives and companies.
And, after processed, it is used to store detergents and oils, it is used in the automobile industry, in fabrics, brooms, carpet threads, bags, beverage and food bottles, lids, paint drums, pots, housewares, etc.
But, despite the fact that PET is recyclable, some companies launch colored packaging in the market with certain shades (red and pink) that make recycling difficult because they can mix with the traditional green, crystal and brown colors, specific for recycling .

3. POLY VINYL CHLORIDE (PVC)

Better known as PVC, it is a chemically resistant material against oxidizing agents, acids, bases and oils. As it is self-extinguishing (it does not propagate fire) it is widely used in civil construction in frames, windows, water or sewer pipes and hoses.
Its mechanical strength also makes it one of the most used plastics in the manufacture of toys and shoes.
Represented by the number 3, it is transparent, light, resistant to temperature, good thermal, electrical and acoustic insulator and also unbreakable. As it is composed only of 43% of petroleum (57% of remaining chlorine), PVC is highly recyclable and has a low manufacturing cost.
Can also be used in:

  • magnetic cards.
  • decorative pieces;
  • balls, buoys, air mattresses and boats
  • food packaging;
  • furniture, clothing, suitcases and bags;
  • interior coating;
  • sewer pipes;
  • irrigation systems;
  • in the manufacture of swimming pools, tunnels, roofs;
  • landfill waterproofing agent.

4. POLYPROPYLENE (PP)

Represented by the number 5, the PP plastic it is harder than polyethylene, retains the properties of its contents for longer — when used in packaging it is unbreakable, transparent, shiny, rigid and non-toxic.
It has high resistance to temperature changes and low moisture absorption. Therefore, it is commonly used in toys, auto parts, tubes, children's diapers, industrial packaging, crates, plastic crates for transporting food, among others.
When molded by the extrusion process, polypropylene is used to manufacture films for making flexible packaging in general, discontinuous yarns, for brushes and brooms or continuous for fabrics, carpets, grain sacks, furniture and sheet coverings.
The material resulting from blowing, on the other hand, is used to manufacture containers for shampoos and other products dand domestic utilities, such as plastic bottles, while it comes from injection, a multitude of products mainly for visual quality, given its great transparency.

5. POLYSTYRENE (PS)

Represented by the number 6, it has properties of waterproofing, lightness, transparency and rigidity, but it is sensitive to shock and impact.
You can introduce yourself as:

  • expanded polystyrene (EPS), popularly known as Styrofoam™, is a type of moldable foam for manufacturing disposable items such as cups, cutlery, plates, protective packaging for transportation, crafts, etc.;
  • solid polystyrene, also used in the manufacture of disposable cutlery, but also in CD and DVD cases, smoke detectors, medical and pharmaceutical products.

It is also found in yogurt pots, ice cream, sweets, manufacture of dishes, lids, razors, internal lining of refrigerators, toys, appliances, automobile parts, among others.

6. POLYAMIDES

Also known as Nylon, they are polymers composed mostly of amides, which, according to their functional groups, can vary the amount of carbon in their polymer composition, changing their properties.
Widely used in the manufacture of synthetic fibers, rugs, carpets, climbing ropes, but also airbags, watches, sports shoes, roller skates, camping tents, among others.
A considerable amount of polyamide is used in vehicles to reduce their weight and increase their fuel economy advantages.

THE RECYCLING PROCESS IN INDUSTRY

The most used process for recycling plastic materials is mechanics — more sustainable and economically viable. In addition to it, the chemical and energy process can be used, viable solutions only for the treatment of continuously reprocessed inputs, as a complement to mechanical recycling.

MECHANICAL RECYCLING

It is the most used method and consists of transforming all material from post-consumption and industrial leftover (shavings) in "smaller pieces" (flakes), which can be used in the production of new materials in the following sequence:

  1. selective destination occurs;
  2. collection of discarded items through waste picker associations, cooperatives or the municipal service;
  3. screening of different types of plastics;
  4. analysis, material cleaning and decontamination;
  5. agglutination (drying), compaction and volume reduction;
  6. waste reprocessing through extrusion, so that the material is melted, homogenized and granulated.

Note: In general, these steps may vary depending on the type of material to be recycled.

CHEMICAL RECYCLING

Used to reprocess plastics that have already gone through many mechanical recycling processes, in order to transform them into basic petrochemical substrates, raw material for the creation of new ones. high quality products.
It does not require a thorough screening, being more tolerant to impurities, however, its cost is higher, as well as large quantities are needed for this process to be economically viable.

ENERGY RECYCLING

It is a technology that transforms plastic inputs into thermal or electrical energy through incineration. It may be interesting, as it creates new energy matrices, but it has a very expensive deployment method and produces highly toxic gases.
It is the process used in thirty-five countries, such as Norway, but still unfeasible in Brazil, which has only one experimental plant on the campus of the Federal University of Rio de Janeiro (UFRJ) — Usina Verde.
Like any other material, plastic can be polluting if disposed of incorrectly. The decomposition time of nylon, for example, is 650 years, long life packages, about 100 years, but soft drink packages, bags, plastic cups and disposable diapers take more than 400 years to decompose.
Despite this, there are many possibilities for reuse through the population's full collaboration in the processes of collecting and directing materials for selective recovery.
Plastic recycling is advantageous because, in addition to fostering the local economy by employing people, who participate in its cycle directly in industries or indirectly as collectors or selectors, benefits the environment by enabling the reduction of greenhouse gas emissions and the volume of this product in landfills, in addition to saving energy and water in production processes.
Do you want to know more about the types of plastics, the process of reusing recyclable materials and the benefit for companies that use this type of material? We've selected an interesting read for you!

13 MAR 6 RECYCLABLE PLASTIC MATERIALS MOST USED IN THE INDUSTRY

Oil refining originates naphtha, an essential material for plastic production, whose carbon and hydrogen molecules undergo a chemical division called cracking, which forms monomers such as ethylene and propylene.
In the polymerization process, new chemical reactions group and order these monomers to form the polymer, long and complex molecular chains, responsible for changing the properties of the plastic, related to size, structure, composition and molecular interactions.
These variations form the two categories of plastic, thermosets — non-recyclable plastics — and thermoplastics, widely used in industry because of their applicability and possibility of reuse and recycling, mainly in post-consumer use.
Recyclable plastic materials have characteristics similar to virgin material: they are waterproof, malleable and durable, they also have other differentials, as they provide better cost-effectiveness in industrial production and sustainability in environmental management.
In this post, we will discuss a little more about recyclable plastic materials and what are the main types of plastics resulting from recycling processes used in the industrial sector. Check out!

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