LLDPE | Extrusion
LLDPE Full Form:
Linear Low Density Polyethylene
What is LLDPE?
A low density form of polymer with a density ranging from 0.915 to 0.930 g/cm3 with a specific number of short chain branches is referred to as linear low density polyethylene (LLDPE). Due to the lack of long chain branching and impurity, it varies structurally from normal low-density polyethylene (LDPE). Because LDPE is recycled to create LLDPE, the linearity of the products is nearly identical to LDPE. LLDPE is often created by copolymerizing ethylene with higher alpha-olefins like butene, hexene, or octene at lower temperatures and pressures.
How is LLDPE made?
Linear low-density polyethylene is produced by copolymerizing ethylene with an alpha-olefin like butene, hexene, or octene co-monomers. The co-monomers are most typically polymerized using the Unipol method, also known as the gas phase process. Ethylene and a catalyst (either Ziegler-Natta or metallocene) are injected into a fluidized bed reactor where copolymerization occurs. After settling at the reactor bottom, the polymer eventually exits the reactor as a powder that is pelletized. When the material is being pelletized, additives are added.
Since this approach occurs at moderate pressures and temperatures, it is more affordable than other polymerization techniques like the slurry and solvent processes. It should be noted that whilst butene, hexene, and other LLDPE mixtures are often generated using gas-phase polymerization, octene is produced using the solvent approach.
Linear low-density polyethylene is frequently made by blow molding, film extrusion, or injection molding due to its specific melt flow characteristics (rheology). Film extrusion is the LLDPE processing method that is used most frequently. The high rate of shrinkage of LLDPE plastic is a result of its semi-crystalline structure, which causes it to occupy greater volume in its melt state than in its solid state.
Uses of LLDPE:
While retaining a high tensile strength, linear low-density polyethylene plastic may extend by a remarkable amount. The polymer's linear properties also make it the perfect choice for walled applications like those described below.
Covering of cables
Buckets and containers
Types of LLDPE:
Injection Molding LLDPE:
Low density linear polyethylene or LLDPE grade with narrow molecular weight dispersion is perfect for injection molding applications. The material has been created with excellent flow properties, enhanced low temperature toughness, stress crack resistance, and gloss. LLDPE is one of the most often utilized substances that flow effortlessly throughout the injection molding process. A single substance can be used to create a variety of things. Some of them are mentioned below-
Roto Molding LLDPE:
LLDPE possesses both a medium stiffness and tensile strength, allowing it to resist large strains before breaking when tugged or stretched. LLDPE is a rotational molding material known for being forgiving despite its durability. Plastic toys, tanks, buckets, bins, containers, and equipment for outdoor leisure are frequently made using LLDPE rotational molding. The resistance of virgin LLDPE materials against environmental and chemical stress cracking is well recognized. These rotational molding materials can benefit from the addition of UV light stabilizers and anti-fungal or anti-microbial additives to make them more suitable for outdoor applications. RotoMolding LLDPE with pigments enables the production of components in a particular color.
Benefits of LLDPE:
Good chemical resistance
High impact strength
Good water vapor
Alcohol barrier properties
Natural milky color
Good stress crack
Forms - LLDPE Granules, Prime Granules, Reprocess Granules, Grinding, Scrap, Rolls, Lumps, Sheet and Finished Good.