Fortunately fort he environment and manufacturers seeking low cost sources of HDPE, HDPE is a highly recyclable material, which when handled correctly can be recycled several times before it begins to show any signs of breaking down. It has a very strong molecular structure which can stand multiple transitions from the liquid to the solid phase without losing structural integrity.

The process by which HDPE regrind is made essentially a long cleaning process. Post consumer scrap HDPE contains all matter of contaminants from food scraps to metals to glass and even other plastics. Because the kerbside pickup recycling process from which the bulk of HDPE is reclaimed is inherently flawed, being carried out in its initial stages by private citizens, a great deal of effort must go into making sure the HDPE regrind is as close to being pure HDPE as is possible before it is on sold to manufacturers.

The first stage of turning reclaimed scrap HDPE into useful HDPE regrind is removing the large contaminants from the scrap HDPE. Typically, scrap HDPE will arrive at the recycler in large bales, which are then broken open. There are different types and grades of scrap HDPE bales. Some have been sorted and cleaned in advance, with labels and lids removed, others are sold as is, with contaminants, labels, and lids still intact.

Once the bales are broken up, the HDPE scrap is put onto a trommel. The trommel is a rotating device that shakes many of the larger contaminants free of the HDPE. Pieces of glass, stones, metals, and a great deal of dirt are removed via the trommel.

Once the bulk of the large contaminants have been removed, the HDPE scrap must be sorted to separate it from non HDPE plastics which are often mistakenly placed in the bale, and other similar foreign objects visible to the human eye.

When it has been ascertained that the HDPE scrap is now comprised almost entirely of HDPE plastic, and any remaining contaminants are too small to be simply picked out, the HDPE scrap is shredded, cut up into small pieces and subsequently cleaned. Chemical solutions, detergents, and high temperatures are all employed in order to clean up the HDPE. This stage is where many stubborn labels and adhesives are finally removed from the HDPE stream.

Float/sink technology is then used to separate HDPE from the dirt and other contaminants which have been released in the washing process. In the float/sink process the washed scrap HDPE is sent into a water tank. HDPE is lighter than water, so it floats, whereas many contaminants, such as small pieces of metal, glass, or rock are heavier than water, and sink to the bottom. The HDPE is then scooped off the top of the water and dried.

The dryer used to dry the shredded HDPE is a large industrial spin dryer which pumps hot air around the HDPE, drying it and making it ready for the final processing before sale.

The HDPE might be further cut up into smaller pieces and sold as HDPE regrind, or it may undergo melt processing to make HDPE pellets or granules. Melt processing involves melting the HDPE regrind down and passing it through a series of filters to remove the last of the contaminants before extruding the melted HDPE through a die and cutting it into pellets. HDPE which has undergone melt filtration is the cleanest form of scrap HDPE, however HDPE regrind is often used as a raw material in applications where very high levels of purity are not required.

HDPE Regrind Supplier

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Virgin HDPE granules are the premium source of HDPE for all HDPE applications. A product of crude oil, virgin HDPE is suitable for use in food packaging, toys, furniture, pipes, and many more applications. Virgin HDPE typically comes in the form of virgin HDPE granules, which must be melted by the end user to obtain liquid HDPE which can then be used in blow molding, injection molding, and the production of film or pipes. Virgin HDPE granules are advantageous in many respects. Their small size results in a quicker melt time, and also a more homogeneous HDPE mix, and transport is also made more simple by the free flowing nature of HDPE granules.

Production Of Virgin HDPE Granules

Virgin HDPE is made by ‘cracking’ naphtha. When naphtha is heated to high temperatures its molecular structure breaks down and it releases ethylene gas. Ethylene is the sole ingredient of HDPE, HDPE being an acronym standing for High Density Polyethylene. Of course, in gaseous form ethylene is of little use, so it must be transformed into polyethylene via one of several reactions.

When ethylene is exposed to high temperatures and pressures, it naturally forms long chains and becomes polyethylene. It is not commercially viable for ethylene to be heated to the great temperatures and pressures needed for this reaction to take place naturally however, so commercial production of HDPE involves catalytic reactions in which a catalyst is added to the ethylene gas to enable polymerization to take place at lower temperatures. Different processes use different catalysts, but all produce high quality HDPE. There is no great difference in the type of HDPE produced during the different types of catalytic reaction, as a catalyst is by definition a substance which is not expressed or included in the product of a reaction.

The Philips catalyst slurry process and the Ziegler catalyst solution process are two of the most commonly used processes in the manufacturing of HDPE today. It should be noted that these processes are capable of producing many different types of polyethylene, from low density LDPE to high density HDPE. Various ‘grades’ of HDPE can also be produced by controlling various elements of the reaction.

The result of the polymerization of ethylene is a translucent viscous liquid which quickly cools and hardens to form a solid. Before the newly produced virgin HDPE solidifies, manufacturers pipe the liquid virgin HDPE through a die and cut it into small sections, which cool to form small solid virgin HDPE granules.

HDPE Granules Supplier

We source virgin (and reporcessed) HDPE granules of all grades. Please contact us through the below form and let us know your detailed requirements. We will get back to you with current HDPE availability and price quotation

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HDPE:
High Density Polyethylene (HDPE) is used for many packaging applications such as snack food packages and cereal box liners, in bottle form as milk and non-carbonated beverage bottles and in injection-molded tub form, for packaging margarine, whipped toppings and deli foods. HDPE has good chemical resistance, because of that it is also used for as packaging for industrial chemicals such as detergents, bleach and acids.

HDPE Pellets:
HDPE resin pellets are small granules usually in shape of a cylinder or a disk with a diameter of a few milimeters. These High Density Polyethylene particles are industrial raw material transported to manufacturing sites where consumer products are made by re-melting the granules and molding them into final products.

HDPE Pellets use:
High Density Polyethylene pellets are used as raw material in production of end user products made from HDPE plastic. Four processes which take HDPE pellets as input are:

HDPE Injection molding: Plastic pellets or granules are fed from a hopper into the heating chamber. An extrusion screw pushes the HDPE pellets through the heating chamber, where the mechanical work and hot sidewalls melt the plastic. Material is softened into a fluid state then at the end of this chamber, the resin is forced at high pressure into a cooled, closed mold. When the HDPE cools to a solid state, the mold opens and the finished product is ejected. This process is used to make products such as yogurt containers, butter tubs, closures and fittings.

HDPE Blow molding: This is a process used in conjunction with extrusion or injection molding. In one form, extrusion blow molding, the procedure forms a continuous half-molten tube of thermoplastic material. A cooled mold is clamped around the tube and compressed air is blown into the tube to conform the tube to the interior of the mold and to solidify it. The goal is to make a uniform melt, form it into a tube with the required cross section and blow it into exact shape of the product. The process is used to make hollow HDPE products and its main advantage is the ability to produce hollow shapes without having to join two or more separately injection molded parts. This method is used to make products such as milk bottles and commercial drums. Another blow molding technique is to injection mold an intermediate shape called a preform and then heat it and blow the heat-softened HDPE into the final shape in a cooled mold. This is the process to make soft drink bottles.

HDPE Extrusion: HDPE pellets or granules are first loaded into a hopper, then fed into an extruder, which is a long heated chamber, through which the HDPE is moved by the action of a continuously revolving screw. The material is melted by a combination of heat from the mechanical work done and by the hot chamber wall metal. At the end of the chamber, the molten plastic is forced out through a small opening to shape the finished product. As the HDPE product extrudes from the opening, it is chilled by air or water. Plastic bags and films are made by extrusion manufacturing.

HDPE Rotational Molding: This process consists of a closed mold mounted on a machine capable of rotation on two axes simultaneously. HDPE pellets are placed in the mold, which is then heated in an oven to melt. Rotation around both axes distributes the molten HDPE into a uniform coating on the inside of the mold until the part is set by cooling. This process is used to make hollow products like kayaks or large toys.

Price of HDPE Pellets:
If you are looking for HDPE pellets price or a list of HDPE suppliers, please fill out the form below and we will send you more information.

Glossary, HDPE

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