Plastic Recycling Conference

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Plastic Recycling Machine Working Principle

What Is A Plastic Recycling Machine?

There are a lot of still will not understand what the plastic recycling machine is? First of all, we need to know the plastic extruder first, plastic extruder is the core machine of plastic recycling machine, which allows the plastic sheet to be melted into a continuous shape for the production of new products. Extruders are usually used in plastic recycling lines and play a key role in converting post-consumer plastics into valuable materials.

Plastic Recycling Machine

Plastic Recycling Machine Working Principle

Plastic recycling machines are designed to process waste plastics and convert them into reusable raw materials, thus helping to reduce the environmental impact of plastic waste. Plastic recycling machines typically work in several key stages: crushing, extruding and pelletizing. Below is an overview of how these processes work:

  1. Shredding
    The first step in plastics recycling is to reduce the size of the plastic waste. Plastic recycling machines typically begin by using a shredder or crusher to chop up the waste plastic into small pieces or pellets. This is necessary because larger plastic items (e.g. bottles, containers) are difficult to handle and process. Chopped plastic is easier to melt and reform into new products.

Principle: Choppers use rotating blades to cut plastic into small pieces. These blades rotate at high speeds to ensure that the waste plastic is broken down efficiently.

  1. Washing
    Shredded plastics usually need to be cleaned to remove contaminants such as dirt, labels or residual contents. This is done in the washing area of the machine, where the plastic pieces are cleaned using water, detergent or a blower.

Principle: The washing process usually combines the use of water, agitation and sometimes chemical solutions to remove contaminants and ensure that the plastic is clean and suitable for reprocessing.

  1. Drying
    Once the plastic has been washed, it must be dried before it can be further processed. Drying is usually carried out using a centrifugal dryer or a hot air blower to remove excess moisture.

Principle: The plastic pieces are spun in a high-speed dryer or passed through a heated chamber to evaporate the remaining moisture, drying them out and making them ready for the next step.

  1. Melting and extrusion
    After drying, the chopped plastic is fed into an extruder where it is heated and melted. The plastic is then forced through a die, forming long strands of melted plastic. This process is called extrusion.

Principle: The extruder uses a screw unit to rotate and push the chopped plastic through a heated barrel. The plastic is gradually heated to its melting point, usually around 200-300°C, depending on the type of plastic. After melting, the plastic is forced through a nozzle (die) to form a continuous strand.

  1. Cooling and Pelletizing
    After extrusion, the plastic strands need to be cooled and solidified. This involves passing the extruded plastic through a cooling system (usually using cold water). Once the plastic has solidified, it is cut into small, uniform pieces called pelletizing.

Principle: The plastic strands are rapidly cooled in a water bath and then a pelletizer (rotating blade or cutter) cuts the cooled plastic into small round pellets. These pellets are the raw material that can be used to make new plastic products.

  1. End product
    After pelletizing, recycled plastics can be used for a variety of purposes, such as making new plastic containers, films, and even molded parts for use in automobiles and other industries. Pellets can be sold to companies for use in their manufacturing processes or for use in the manufacture of new recycled products.
Plastic Recycling Machine Working Principle

What Are The Processes Of Plastic Recycling Machines?

Water Ring Pelletizing

Water ring pelletizing is a commonly used process for extrusion and pelletizing in plastic recycling, especially for thermoplastic materials. The key feature of this process is the use of a water ring to cool and cut molten plastic.

Working Principle:
  • Extrusion: Molten plastic is extruded from the extruder, forming continuous plastic strands (usually in a long, thin shape).
  • Water Ring Cooling: The molten plastic strands are passed through a water ring system. This system consists of a water bath and high-speed rotating blades. As the plastic strands pass through the water ring, the water cools and stabilizes the plastic.
  • Cutting: After cooling, the plastic strands are cut into small, uniform pellets by rotating knives.
  • De-watering: The pellets are then typically processed through a centrifugal dryer to remove any residual water before drying and packaging.
Advantages:
  • Uniform Pellets: Water ring pelletizing produces uniform, small pellets that are ideal for high-quality recycled plastic.
  • Efficient Cooling: The water ring efficiently cools the plastic, preventing the pellets from sticking together.
Applications:

Water ring pelletizing is commonly used in plastic recycling processes for materials like PVC, HDPE, and PE.

Water Ring Pelletizing

Water Quenching and Pulling

Water quenching and pulling is a process that uses water to cool and solidify plastic, commonly applied in the production of long strips or fiber-like plastic products. It is used extensively for recycling plastics and making new materials, especially when pulling plastic into a continuous shape.

Working Principle:
  • Extrusion: Molten plastic is extruded into long strips or fibers.
  • Water Cooling: The extruded plastic enters a water bath where it is quickly cooled by the water, solidifying the plastic as it passes through the cooling zone.
  • Stretching: After cooling, the plastic strips or fibers are pulled through stretching devices that control the speed and tension of the material to ensure uniformity and smoothness.
  • Pulling: The solidified plastic is pulled out and maintained in shape, forming the final product.
Advantages:
  • Uniform Stretching: Water cooling ensures uniform stretching of plastic strips or fibers, which is crucial for creating high-strength materials.
  • Efficient Cooling: Water cooling rapidly reduces the temperature of the plastic, minimizing deformation and losses during the process.
Applications:

This process is commonly used for the production of plastic pipes, sheets, films, ropes, and other similar products, as well as in the recycling of waste plastic.

Water Quenching and Pulling

Low-Temperature Air Cooling

Low-temperature air cooling is a method that uses cool air to solidify molten plastic, typically used in extrusion processes to cool and solidify the material after it has been formed. This method is suitable for plastics that require precise surface quality or are sensitive to water cooling.

Working Principle:
  • Extrusion: Molten plastic is extruded into sheets, strips, or other shapes.
  • Air Cooling: After extrusion, the molten plastic is exposed to low-temperature air, which cools the material. The air is chilled using cooling systems to control the rate of cooling.
  • Temperature Control: The cooling system adjusts air flow and temperature to ensure the plastic solidifies evenly, without causing defects on the surface.
Advantages:
  • High Surface Quality: Air cooling avoids the water marks or surface imperfections that can occur with water cooling, making it ideal for products requiring a smooth surface finish.
  • Wide Applicability: Suitable for a wide range of plastic materials, especially for those that are temperature-sensitive and could be adversely affected by water cooling.
Applications:

Low-temperature air cooling is widely used in cooling and solidifying plastic films, sheets, profiles, and other products that require precise surface quality.

What Plastics Can Be Recycled In A Plastic Recycling Machine?

Plastic recycling machines can handle all types of plastics, but not all plastics are suitable for recycling. The recyclability of a plastic depends on its chemical composition, structure and the type of recycling process used. The following are the most common plastics that can be recycled in a plastics recycling machine:

  1. Polyethylene terephthalate (PET or PETE)
    Common Uses: Bottles (e.g. soft drink bottles), food containers, clothing (fleece jackets) and packaging.
    Recyclability: PET is widely recyclable and is one of the most common machine recyclable plastics. It can be melted down and transformed into new products such as clothing, carpeting and new bottles.
    Recycling Process: PET is usually cleaned, shredded, melted and pelletized. 2.
  2. High Density Polyethylene (HDPE)
    Common Uses: Milk bottles, detergent bottles, juice bottles, toys and some food containers.
    Recyclability: HDPE is one of the easiest plastics to recycle. It is often recycled into new containers, pipes and plastic lumber.
    RECYCLING PROCESS: HDPE is cleaned, crushed, and then processed into pellets or other forms.
  3. polyvinyl chloride (PVC)
    Common Uses: Piping, flooring, window frames and shrink wrap.
    RECYCLABILITY: PVC can be recycled but requires special handling. PVC can be used to make new pipes, tiles and flooring, but the recycling process can release toxic chlorine gas if not handled properly.
    Recycling process: PVC is shredded, cleaned, and sometimes reprocessed into new products such as tiles, flooring, or pipes.
  4. Low Density Polyethylene (LDPE)
    Common Uses: Grocery bags, certain food packaging and clothing.
    Recyclability: LDPE can be recycled, but less often through curbside programs. It is often recycled into products such as new bags or floor tiles.
    Recycling process: LDPE is cleaned, pulverized, and extruded into pellets or new plastic products.
  5. Polypropylene (PP)
    Common Uses: Food containers, bottle caps, straws Food containers, bottle caps, straws and some plastic furniture.
    RECYCLABILITY: Polypropylene can be recycled but is not widely accepted in curbside recycling programs. It can be used to make new products such as signal lights, brooms and industrial containers.
    RECYCLING PROCESS: Polypropylene is washed, shredded and melted into new shapes and products.
  6. Polystyrene (PS)
    Common Uses: Disposable tableware, foam packaging, CD cases and food containers.
    Recyclability: Polystyrene can be recycled, but recycling is not common due to pollution and low demand for recycled polystyrene. It is mainly recycled into insulation and other non-consumer products.
    Recycling process: Polystyrene can be reprocessed after cleaning, shredding and melting, but recycling rates are low due to handling difficulties and contamination.
  7. Other plastics (other or mixed plastics)
    Common Uses: Multi-layer packaging, some plastic toys and various household products.
    Recyclability: Plastics labeled “other” usually consist of mixed materials or plastics that do not fall into one of the above categories. These plastics are more challenging to recycle and often require specialized equipment or methods.
    Recycling Process: Recycling of these materials is more complex and may require sorting and cleaning before processing into new products, often by specialized recycling programs.

How to Sort Plastics: A Step-by-Step Guide

What Plastics Can Be Recycled In A Plastic Recycling Machine?

Why Are Plastic Recycling Machines The Best Investment?

Plastic recycling machines are a strong investment for several key reasons:

Growing demand for sustainable development


With growing concerns about the environment, governments and industries are pushing for more sustainable practices. The demand for recycled plastics is also growing as businesses seek to reduce their carbon footprint and meet recycling targets. Investing in a plastics recycling machine puts you at the forefront of this movement.

Profit from waste


Plastic waste is plentiful and recycling can turn waste into valuable products such as pellets, granules or fibers. These materials can be sold to manufacturers who need recycled plastic products, creating a steady stream of income.

Cost Savings for Manufacturers


Recycled plastics are often cheaper than virgin plastics, so manufacturers can reduce production costs. By offering recycled materials, you can tap into a growing market of companies looking for cost-effective, sustainable solutions.

Government incentives and support


Many governments offer incentives, subsidies or tax breaks to companies involved in recycling. This can significantly reduce initial investment costs and provide financial support for your business.

Long-term profit potential


As plastic pollution remains a global problem, the recycling industry is likely to see continued growth. With the right technology, plastics recycling can continue to meet the demand for recycled materials, providing long-term profitability.

Positive impact on the environment


By reducing plastic waste, recycling machines help to reduce pollution and conserve resources, in line with global efforts to create a circular economy. This positive impact also enhances brand reputation, especially when sustainability is a key part of a company’s business model.

Diversifying applications


Recycled plastics can be used in a wide range of applications in industries such as packaging, construction, automotive and textiles. This diversity makes plastics recycling a flexible and scalable business opportunity.

Best Plastic Recycling Machine Manufacturer Recommendation

JianTai’s plastic recycling machines are among the best in the industry due to their high performance, versatility, durability, and energy efficiency. With advanced technology, robust designs, and outstanding after-sales support, JianTai offers businesses a reliable and cost-effective way to process plastic waste into valuable reusable materials. Whether you’re a small recycler or a large industrial operation, JianTai’s machines provide the perfect solution to help you reduce waste, increase efficiency, and achieve long-term profitability.

If you are looking to invest in high-quality plastic recycling equipment, JianTai Machine is the partner you can trust for innovative and sustainable solutions.

For more information, visit JianTai Machine’s website, or contact us at ding@jiantaimachine.com for a consultation.