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In this page you will find free data about Linear Low Density Polyethylene (LLDPE), including:
- What is LLDPE
- How to make LLDPE
- LLDPE uses and applications
This page presents brief synopsis of LLDPE production technology, describing, in a concise way, relevant technical and economic aspects. Each manufacturing process description will consist of:
- Major process steps
- Simplified, schematic flow diagram & key equipment
- Important safety or environmental considerations
- Economic perspective, comprising capital expenditures and/or operating expenses
Linear Low Density Polyethylene (LLDPE) Manufacture via Solution Process
Polyethylene (PE) is the world’s largest volume commodity polymer. Along with high-density (HDPE) and low-density (LDPE) polyethylene, linear low-density polyethylene (LLDPE) is one of the three main types of PE. The global market for LLDPE is over 20 million metric tons per year, corresponding to about 30% of the total PE produced.
In LLDPE production, three major types of low-pressure technologies are used: slurry, solution and gas-phase processes.
LLDPE is produced by copolymerization of ethylene with alpha-olefins using Ziegler-Natta catalysts. The most common co-monomers used in LLDPE production are 1-butene, 1-hexene and 1-octene.
The flowsheet illustrates the process for butenebased LLDPE production via a solution technology similar to Nova Chemicals’ (Calgary, Alta.; www.novachem.com) solution-phase technology, known as SclairTech. The process shown is a swing process, which is also capable of producing different LLDPE and HDPE grades by utilizing other alphaolefinsas co-monomers.
The process can be divided into four main operation areas: purification and catalyst preparation; reaction; distillation; and finishing.
Purification and Catalyst Preparation
The cyclohexane solvent, ethylene and comonomers are sent to fixed-bed adsorption systems to remove water, oxygen and other polar impurities. The catalysts used in the process are based on mixtures of titanium and vanadium compounds, in conjunction with aluminum alkyls cocatalysts. These components are mixed with solvent and pumped to the polymerization reactor.
Ethylene and 1-butene comonomer (in case of butene-based LLDPE) are ...
An economic evaluation of the solution-phase LLDPE process was conducted based on ...
Linear Low Density Polyethylene (LLDPE) Manufacture via Gas-Phase Process
Linear low-density polyethylene (LLDPE) is a copolymer of ethylene and longer-chain alpha-olefins, manufactured on commercial scale via low-pressure polymerization processes. The main technologies suitable for LLDPE production include slurry, solution and gas-phase processes. The most common comonomers used commercially are 1-butene, 1-hexene, and 1-octene.
LLDPE is used in a broad range of applications due to its attractive mechanical properties and low cost. The greatest demand for LLDPE resins is associated with plastic film and sheet end-use, representing most of the total production. Compared to blown films of low-density polyethylene, LLDPE films exhibit tremendous toughness, dart impact and puncture resistance.
The figure below presents a simplified flow diagram of the gas-phase polymerization process for LLDPE production, using 1-butene as a co-monomer, showing the main pieces of equipment. Examples of commercial gas-phase processes for LLDPE production similar to the one discussed here include: Univation Technologies’ (Houston; www.univation.com) Unipol and Ineos Technologies’ (Rolle, Switzerland; www.ineos.com) Innovene G.
Feed preparation and polymerization
Initially, raw materials are purified ...
Polymer degassing and vent recovery
In the purge bin ...
Pelletizing and finishing
The polymer powder ...
An economic evaluation of the process described here was conducted based on data ...