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 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:
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