Low linear density polyethylene (LLDPE) is a branch of HDPE that is synthesized in a similar way, except that LLDPE contains higher grade monomers such as hexane or octane. Bonding of commonomers in a chain creates short-chain branches that have a certain length. By controlling the number of chain nodes through the commonomer type, the degree of crystallinity in terms of density can be controlled. Different types of LLDPE are known as very low density polyethylene (VLDPE) and ultra low density polyethylene (ULDPE). The density of LLDPE is usually in the range of 0.88-0.93 LLDPE has a type of combined processing (melting temperature = 260-240, 125-115). The inside of the extruder works similarly to HDPE, requires more torque, and often uses a grooved feed opening to enter the extruder. However, after leaving the die, its bubble shape is similar to that of LDPE, although its melt resistance is lower than that of LDPE. This problem is solved by using a double-edged air ring, which keeps the bubble aerodynamically stable by providing a large volume of cold air. The LLDPE solid state properties are also a reflection of the combination of HDPE and LDPE properties. Its strength is higher than LDPE and close to HDPE resistance. However, it has more softness and therefore less hardness than LDPE.
