What are the LLDPE plastic films and what are the main uses?
The properties of the resin are generally reflected in the melt index and density. The melt index reflects the average molecular weight of the resin and is mainly controlled by the reaction temperature. The average molecular weight has nothing to do with the molecular weight distribution (MWD). The influence of catalyst selection on MWD.The density is determined by the concentration of the comonomer in the polyethylene chain. The monomer density is used to control the number of short branches (whose length depends on the type of comonomer used) to control the resin density. The higher the concentration of comonomer, the lower the resin density.Structurally, LLDPE differs from LDPE in the number and type of branched chains, while high pressure LDPE has long branched chains, while linear LDPE has only short branched chains.Structurally, LLDPE differs only from HDPE in the number of short branches. HDPE has fewer short branched chains and therefore is of higher density.The physical properties of LLDPE are controlled by its molecular weight, MWD, and density.
The production of LLDPE begins with transition metal catalysts, especially Ziegler (Ziegler) or PHILPS (Phillips). A new process based on the olefin olefin metal derivative catalyst is another option for LLDPE production. The actual polymerization can be carried out in a solution and gas phase reactor. In general, butene is copolymerized with ethylene in a solution phase reactor, butene. Polymerization of Cyclohexene with ethylene in a gas phase reactor. The LLDPE resin generated in the gas phase reactor is in the form of particles and may be powdered or further processed into pellets for sale.With hexene and octene is based on a new generation of super LLDPE from mobile, union carbide. Novacor and Tao plastics et al. These materials have great toughness limit and have new potential in the application of automatic bag removal.
LLDPE is used in all traditional polyethylene markets to enhance resistance to stretch, penetration, impact and tear resistance, making LLDPE suitable for films. Its excellent environmental stress cracking resistance, low temperature impact resistance and warpage resistance make LLDPE attractive for tube, sheet extrusion and all molding applications. LLDPE's latest application is used as mulch for waste landfills and waste liquid pools.
The LLDPE polymers generated by copolymerization process have a narrower molecular weight distribution than the general LDPE and have a linear structure with different rheological properties. The melt flow characteristics of LLDPE meet the requirements of the new l process, especially the film extrusion process, which can produce high quality LLDPE products.
Linear low density polyethylene is structurally different from ordinary low-density polyethylene because of the absence of long branched chains. The linearity of LLDPE depends on the different manufacturing processes of LLDPE and LDPE. LLDPE is usually produced at lower temperatures and pressures by copolymerization of ethylene and advanced a olefins such as butene, cyclohexene, or octyl.
