APPLICATIONS OF HDPE RECYCLED PLASTIC PELLETS

The most common application of recycled HDPE is the production of plastic bottles. Due to its durability, bearing capacity and high recyclability, HDPE recycled plastic is considered an ideal raw material for the production of bottles and barrels. Especially containers containing pesticides or hazardous materials. Besides, recycled HDPE is also used to manufacture household items such as plastic cabinets, bathroom partitions, etc. Due to its superior moisture resistance and heat resistance. In daily life, you can easily come across items made from recycled HDPE such as children's toys and especially nylon bags.

1. Producing nylon bags from recycled HDPE
a. What is recycled HDPE plastic bag?
► HDPE recycled plastic bags are thin, light and flexible plastic bags. Extremely convenient in people's daily life. Due to its flexibility and smoothness, HDPE recycled plastic bags have a slightly higher production cost than ordinary nylon. However, nylon bags are still of higher quality.
► Recycled HDPE plastic bags are often used to make food packaging or food,... HDPE recycled plastic bags are mainly used to preserve foods and utensils to avoid environmental influences. outside school. The popular recycled HDPE plastic bag is large in size. Usually used to store goods of relative weight. In addition, HDPE recycled plastic bags are also used to print advertising products. Or bags printed with logos and brands of stores and businesses.

b. Characteristics of recycled HDPE plastic bags
HDPE recycled plastic bags are derived from Polyethylene. Therefore, they all have the characteristic properties of polyethylene.
► The surface is transparent, glossy, with a matte luster and is flexible.
► Good resistance to steam and water.
► Poor resistance to grease and gases (O2, CO2, N2).
► When in contact with aromatic essential oils or detergents, they are easily swollen and damaged. For example: Alcohol, Acetone, H2O2,...
► Due to the property of allowing gases and fragrances to penetrate the packaging layer. So it will be possible to retain the smell of the food in the packaging.
c. Some popular models of recycled HDPE plastic bags and their applications
► Clear Recycled HDPE Bags: Clear recycled HDPE bags have a smooth surface and flexible durability. The smallest size is 10x15cm and the required thickness is about 10 - 200mic. Produced in large format, widely used in agriculture - industry. Or used to store all kinds of food, retail, ...
► Anti-static recycled HDPE bags: Anti-static recycled HDPE bags have good electrostatic discharge ability and are black in color. Has stable electrical conductivity and good light blocking. Therefore, they can protect sensitive electronic devices and components from harmful agents (electromagnetic waves, static electricity). Reduce the harmful effects of static electricity generated when there is friction in the manufacturing process. It also resists other types of external static electricity.
► Vacuum Recycled HDPE Bags: All vacuum recycled HDPE bags are made of thick and tough nylon. Can be reused many times and does not contaminate preserved foods. The lid slot and suction valve of the vacuum bag are both manufactured with silicone. Increases the elasticity and air tightness of the bag.
The vacuum recycled HDPE bag is mainly used to store bulky items. Or keep clothes from dirt, not moldy. Prevent objects from getting wet in the air. In addition, vacuum recycled HDPE bags are also used to pack foods and non-food items. These can be mentioned as: Store files, photo albums, DVDs, important papers, jewelry, ...
d. Production process of recycled HDPE plastic bags
► Step 1: Extrusion - blowing
This is the most important stage. Because it determines the thickness of the recycled HDPE plastic bag. The starting material for production is recycled HDPE plastic pellets.
Recycled plastic granules are put into the extrusion - blowing machine. They are melted under controlled conditions to create a ductility (3800F). Next, they are extruded through a tube mold. Take advantage when still at high temperature, one end of the tube will be fixed. Then proceed to blow air to form bubbles (membrane cooling). Proceed to raise, pull the lead thickness, length to the desired size. When reaching a height of 20 - 35 feet, the cold film will form 2 flat layers when passing through the slot with 2 rollers. Then, they will be rolled into separate film rolls.
► Step 2: Proceed to print
The film rolls will be moved to the recycled HDPE bag printer unit. Depending on the design, printing color, quantity, etc., this stage will be carried out by screen printing, gravure or flexographic printing. If the bag roll size is large, it will be suitable for gravure printing.
In this step, the required shapes and letters will be made. Therefore, this is the step that will determine the aesthetics of the design printed on the bag. This is also the step that customers are most interested in. Because they will determine whether the logo, text of an individual, organization or business is eye-catching or not. Therefore, this step will have more advantages when applying modern printing technologies.
► Step 3: Finishing stage
This is the final stage of the production process of HDPE nylon bags. In this step will include stages: Cutting, marking, folding, stamping straps, attaching straps, ... depending on the design of the bag. The small stages in this step will help shape the shape, size and quantity of the HDPE bag. This stage is carried out entirely on modern machinery lines. Therefore, the accuracy is very high.

2. Production of HDPE film
a. What is HDPE film?
HDPE film is also known as shrink film or tight film. This is a thin plastic film that is very tough and difficult to break. Capable of sticking to many different types of surfaces. These can be mentioned as plastic, wood, aluminum, glass to all kinds of metal, ... HDPE plastic film used to wrap goods has the English name is HDPE Stretch film.

Waterproof HDPE Membrane

b. HDPE film production process
There are two processes for producing HDPE film including blowing and laminating methods:
Production of HDPE film by blowing method
► Step 1: Mix the recycled HDPE resin with additives (if any).
► Step 2: Put the mixture into the extruder
Here, the plastic mixture will be gradually heated to 200˚C - 275˚C and melted. Next, the molten plastic mixture is passed through the filter, which is a metal mesh. To filter the mixture and remove impurities as well as raw materials that have not yet melted.
► Step 3: The molten plastic material mixture will be poured into the scarf-shaped mold. This mold is erected to create a product that is a thin plastic tube.
► Step 4: Next, they will be inflated through the air hole located in the middle of the mold.
► Step 5: Carry out cooling
The membrane tube will be cooled by the cooling system and the surrounding high-speed air ring.
► Step 6: After being cooled, the membrane tube will be passed through a roller to conduct flattening.
► Step 7: Roll the film
HDPE film after flattening will form a double film, and be kept or cut into 2 single films. Then pass through the rollers to roll back.
Production of HDPE film by lamination
► Step 1: Mix the resin mixture with additives (if any).
► Step 2: Put them into the extruder. Here the plastic beads will be gradually heated to 200˚C - 275˚C and melted. Next, the molten plastic mixture is passed through the filter, which is a metal mesh. To filter the mixture and remove impurities as well as raw materials that have not yet melted.
► Step 3: The molten plastic material mixture is put into a T-shaped mold. To be able to evenly distribute the amount of plastic mixture introduced into each shaft.
► Step 4: The molten plastic through the T-shaped mold is put into the roll forming rollers to shape the product in terms of large and small size and thin thickness of the film.
► Step 5: Cool. The HDPE film is then cooled by pulling through a sealed water tank under the action of a vacuum.
► Step 6: After cooling, the HDPE film is cut on 2 sides and curled.

3. HDPE foam
a. What is HDPE foam?
► HDPE foam - Polyethylene foam is a foam film made from high-density polyethylene, also known as HDPE. When re-melting the recycled HDPE plastic, the microscopic air bubbles will be trapped to create a solid super-bonded form. The common Vietnamese name of this material is HDPE foam, HDPE foam or HDPE foam...
► HDPE foam is classified into 3 types:
      + HDPE foam in rolls.
      + HDPE foam in the form of bags.
      + HDPE foam in the form of bars, sheets or shaped boxes.
b. Features of HDPE foam
HDPE foam possesses many unique characteristics that no other material can replace.
► Flexibility, toughness and effective resistance to chemicals and water.
► Possesses high elasticity.
► Light weight so it can float on water surface.
► Not affected, affected by bacteria or mold.
► HDPE foam has sound insulation and heat resistance.
c. Application of HDPE foam
Depending on different industries, HDPE foam will be used appropriately as follows:
Electronic packaging industry
For the electronics packaging industry, HDPE foam is used to make:
► Thin sheets of foam are used as padding for cartons.
► Shaped foam box to fix and protect structural details of components.
► HDPE foam membrane is resistant to static electricity, friction or accumulation of electricity, which can easily cause fire and explosion in electrical circuits.
► Used as a cushion to prevent scratches on the screen surface of the phone during transportation.
► Used to into the openings in the inside of the cargo box.
► Used to wrap dishes, household items or protect glass bottles when transporting.
► HDPE foam protects the gift box.
► Used to preserve furniture that is not dusty or moldy.
Shipping industry
In the shipping industry, HDPE foam is used to help:
► Used to protect both the inside and outside of the box.
► For ing dunnage into cargo slots.
► Used to protect fragile items. For example, cosmetics, glass bottles, wine bottles, ...
Garment industry
In the garment industry, HDPE foam is also commonly used. For example, making life jackets, making thermal vests, making pillows for the cockpit, making seat cushions, making pads for shoes.
Construction industry
In the construction industry, HDPE foam has affirmed its mission and position in this industry. Through the following applications:
► Used to prevent heat in constructions, apartments, barns, houses, ...
► Used as a material to prevent concrete settlement.
► Materials to make cushions for natural wood floors or industrial wood floors.
► Used for soundproofing in the singing room.
Agricultural product packaging industry
Styrofoam is used to wrap export agricultural products such as bananas, melons, apples, guava, etc. Or is used to preserve heat and preserve lychee when exporting to foreign countries.

4. In the production of HDPE pipes
HDPE pipes have been mainly used to transport liquids. Due to its ability to withstand harsh chemicals without corrosion or leakage. Besides, the welds on the surface are very strong. HDPE recycled plastic pellets are considered as the ideal material for the gas industry. In addition, the welds on HDPE are very strong and tight so there is no leakage. Has outstanding advantages in terms of longevity and safety. Not to mention the significant savings on installation costs. There is an improvement in the material as well as the performance of the HDPE material. Applied to water pipelines, chemicals and in other industries needed for conveying liquids or gases.
a. Mechanical properties of HDPE pipes
► Density: 0.95 - 0.97 g/cm3
► Minimum breaking strength: 21 Mpa
► Coefficient of thermal expansion: < 0.2 mm/m.˚C
► Surface resistivity: > 1013
► Maximum working temperature: 45˚C
► Minimum micro-softening temperature: 120˚C
► Brittle and fracture temperature: < 0˚C
► Electrical and thermal insulation.
b. Application areas
► In light industry: Making water supply and drainage pipes. Large-sized sewage pipes used in urban areas or industrial zones.
► Mining industry: Used to make sewage pipes. Used in mining industry or sewer pipes.
► Energy industry:
     + Making conduits for electrical wires and cables.
     + Make hot steam pipes (heating pipes).
     + Make a drainage pipe.
     + Raw materials for the production of cold water supply pipes (pressure 4 - 10kg/cm2).
     + Making conduits for the postal industry. Fiber optic pipes can be used in places with low temperatures (ice and snow).

c. Advantages and benefits of using HDPE pipes
► With years of development all over the world, the quality of HDPE water pipes is highly appreciated. Light weight, can be transported and installed easily.
► High impact resistance, so it can resist cracking well.
► Not corroded by chemicals or rotting.
► High strength HDPE pipes. Can be transported and installed conveniently without physical damage.
► It is resistant to ultraviolet rays for a long time so it can withstand direct sunlight.
► The pipe wall has high elasticity thereby preventing the formation and development of cracks.
► Due to its high elasticity, it is used to create smaller accessories to connect together. The bent HDPE pipe has a radius that falls between 20 and 25 times its outside diameter. Easy to carry out installation work due to its high elasticity. The coil can be bent upto 1000mm with an outer diameter &ge 1200mm.
► Less affected or affected by land surface fluctuations. For example earthquakes, landslides, etc.
► Wide range of HDPE pipes available with different pressure resistance. HDPE pipes are manufactured with 12 pressure levels ranging from 2.5 to 32 bar.
► The joints on the pipe have no cracks, are difficult to break or deform.
► Can be safely installed on many surfaces. These can be mentioned as under the sea, river or low temperature terrain.
► Suitable connection methods such as sealing, threading, heat sealing, etc. are available.
► The inner tube surface is glossy and smooth. Contributing significant savings in service or periodic maintenance costs.
► Long life even in harsh weather conditions.
► Not acidified or alkalized by organic solvents such as fatty alcohol, Acetone, Etylic, Glyceryl, .. or acid. Commonly used in the food and pharmaceutical industries.