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A Brief Description Of The Common Processing Methods Of Plastic Products
- Jul 26, 2018 -

A brief description of the common processing methods of plastic products


What do you know about common plastics processing methods? Let's get to know it together.


Material processing is also called plastic molding process. It is the general term of converting synthetic resin or plastic into plastic products. It is a larger production department in the plastic industry.


With ethylene as the main raw material, propylene, 1- butene and hexene are copolymers. Under the action of catalyst, the process of slurry polymerization or gas phase polymerization is used. The obtained polymers are prepared by flash, separation, drying and granulation. It includes sheet extrusion, film extrusion, tube or profile extrusion, blow molding, injection molding and rotational molding.


The processing method of plastic products:


Extrusion Blow Molding:
The grade used for extrusion production generally has a melt index of less than 1 and a MWD of medium width to width. Suitable melt strength can be obtained at low MI during processing. Wider MWD grades are more suitable for extrusion because they have higher production speed, lower die pressure and reduced melt fracture trend.


Blow molding:
More than HDPE1/3 is sold in the United States for blow molding purposes. These ranges from bottles containing bleach, oil, detergent, milk and distilled water to large fridges, fuel tanks and canisters. The characteristics of blow molding grade, such as melt strength, ES-CR and toughness, are similar to those used for sheet and thermoforming applications, so similar grades can be used.


Injection molding:
HDPE has countless applications ranging from reusable thin wall beverage cups to 5-gsl cans, consuming 1/5 produced by domestic HDPE. The injection molding grade has a general melt index of 5~10, and has a relatively high fluidity grade with low toughness and fluidity. Applications include daily necessities and food thin-walled packages; ductile and durable food and paint cans; high resistance to environmental stress cracking applications such as small engine fuel tanks and 90-gal garbage cans.


Roll plastic:
Materials processed by this process are usually crushed into powder materials to melt and flow in the thermal cycle. Two types of PE are used for rolling plastic: general and crosslinkable. The general level MDPE/HDPE usually has a density range from 0.935 to 0.945g/CC, with a narrow MWD, which makes the product have a high impact and the smallest warp, and its melt index range is generally 3 - 8. Higher MI grades are usually not applicable because they do not possess the impact and environmental stress cracking resistance of rotational molding products.
The high performance rotational molding application department makes use of its unique properties of chemical crosslinking grade. These grades have good fluidity in the first section of the molding cycle, and then cross link to form their excellent resistance to environmental stress cracking and toughness. Wear resistance and climate resistance. The crosslinkable PE is only suitable for large containers, ranging from 500-gal transporting various chemical storage tanks to 20000-gal agricultural storage tanks.


Film:
PE film processing is usually done by conventional blow molding or flat extrusion. Most PE is used for thin films, general low density PE (LDPE) or linear low density PE (LLDPE) are available. The HDPE film level is generally used in places requiring superior tensile properties and excellent impervious properties. For example, HDPE films are commonly used in commodity bags, grocery bags and food packaging.