Dissolve in 0.3 of the LDPE plastic raw materials what?
However, according to ASTM's D-1248-84, the density range of 0.926 to 0.940 g / cm3 is of medium density polyethylene (MDPE). A new generation of LLDPE expands its density to a plastic body (0.890 to 0.915 g / cubic centimeter) and an elastomer (<0.890 g / cm3). But the American Plastics Industry Association (SPI) and the American Plastics Industry Council (APC) extend the range of LLDPE to plastic bodies, not elastomers. In the 80s of the last century, Union Carbide and Dow Chemical called their early sales of elastomers and elastomers as very low density polyethylene (VLDPE) and ultra low density polyethylene (ULDPE) resins.
LLDPE, which was industrialized by Union Carbide in 1970s, represents a major change in polyethylene catalyst and process technology, which has significantly expanded the range of polyethylene products. LLDPE with coordination catalyst instead of free radical initiator, and with low cost low pressure gas phase polymerization reactor to replace the high cost, in a relatively short period of time, with its excellent performance and low cost, has replaced the LDPE in many areas. At present, LLDPE permeates almost all traditional polyethylene market, including film, molding, tubing and wire and cable.
The molecular structure of the conventional LLDPE is characterized by its linear backbone, with only a few or no long branched chains, but contains some short branched chains. Without long branched chains, the crystallinity of polymers is higher.In general, LLDPE resins are characterized by density and melt index. The density is determined by the concentration of comonomer in the polymer chain. The comonomer concentration determines the short branch chain in the polymer. The length of the short branched chain depends on the type of comonomer. The higher the concentration of comonomer, the lower the density of the resin. In addition, the melt index is a reflection of the average molecular weight of the resin, mainly determined by the reaction temperature (solution method) and the addition of chain transfer agents (gas phase method). The average molecular weight is independent of the molecular weight distribution, and the latter is mainly influenced by the type of catalyst.
Linear low density polyethylene (English: Linear Low Density Polyethylene, referred to as: LLDPE), linear low density polyethylene (LLDPE), is a senior of ethylene and alpha olefins (such as -1, -1, butylene hexene octenes methylpentene -1, four -1) in the presence of catalyst, a copolymer with high or low pressure polymerization of density is between 0.915 ~ 0.9 low density polyethylene using 40 g / cm3.
Low density polyethylene (Low density polyethylene, referred to as LDPE) is usually based on ethylene monomer in high pressure 98 ~ 294MPa, with oxygen or organic peroxide as initiator, the polymerization of the polymer, the density of 0.910 ~ 0. 9259/cm3. medium density polyethylene (MDPE) density is 0.926 ~ 0.9409/cm3; very low density polyethylene (VLDPE) density below 0.910g/cm3.
