Medium-Density Polyethylene in Packaging Applications
3 patents in this list
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Medium-density polyethylene (MDPE) packaging materials operate in demanding environments where they must maintain structural integrity while resisting impact, environmental stress cracking, and thermal deformation. Current MDPE formulations achieve densities between 0.926-0.940 g/cm³, but face limitations in achieving optimal combinations of rigidity, impact resistance, and processability needed for modern packaging requirements.
The fundamental challenge lies in engineering molecular weight distributions and blend compositions that balance mechanical properties with processing characteristics, particularly in applications requiring thin-wall sections and cold temperature performance.
This page brings together solutions from recent research—including metallocene-catalyzed PE compositions with narrow molecular weight distributions, controlled crosslinking approaches, and strategic polyolefin blending ratios. These and other approaches focus on achieving improved property combinations while maintaining processability in commercial packaging operations.
1. Polyethylene Composition Incorporating High-Density Metallocene PE with Narrow Molecular Weight Distribution and Polyolefin Blends
TOTAL PETROCHEMICALS RESEARCH FELUY, 2010
Polyethylene composition with improved balance of rigidity and impact resistance for applications like films. It contains a high density metallocene PE with density 0.947-0.970 g/cm3 and MWD < 4, along with other polyolefins like LDPE, LLDPE, MDPE, HDPE, EVA. The metallocene PE provides rigidity, while the other PE types boost impact resistance. The composition allows thinner films with comparable rigidity and impact resistance to conventional PE films.
2. Polyethylene Resin Composition with Specified Melt Flow Rate and Density Comprising LLDPE, LDPE/HDPE, and HLLDPE Blend Ratios
MITSUI CHEMICALS INC, 1999
Polyethylene resin composition for heavy-duty packaging bags that provides improved low-temperature properties, such as drop bag strength, for bags used in cold areas. The composition has a specific melt flow rate, density, and tension range. It uses a blend of linear low-density polyethylene (LLDPE), linear medium/high-density polyethylene (LDPE/HDPE), and high-pressure low-density polyethylene (HLLDPE). The blend ratios are 40-70% LLDPE, 1-55% LDPE/HDPE, and 5-29% HLLDPE.
3. Crosslinked Polyethylene Composition with Controlled Molecular Weight Blending and Limited Crosslinking Ratio
YOSHII NAOJI, ASAHI KASEI KOGYO KABUSHIKI KAISHA, MORIGUCHI KISOO, 1985
A crosslinked polyethylene composition with improved physical properties and molding properties for applications like blow molding and extrusion. The composition is obtained by lightly crosslinking and intimately blending a high molecular weight polyethylene (A) with a low molecular weight polyethylene (B). The crosslinking is done to a limited extent to avoid swelling in solvents like xylene. The composition has desirable properties like high impact strength, high ESCR, improved melt tension, and reduced die swell compared to crosslinking polyethylene alone. The crosslinking ratios are controlled to balance properties.
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