Low-Density Polyethylene in Packaging Applications

Preparing low-density polyethylene (LDPE) resin for food packaging bottle combination caps using a high-pressure polymerization process. The LDPE resin has optimized properties for food packaging caps by adjusting the polymerization conditions. The resin has a narrow molecular weight distribution, high degree of methyl branching, and low density. This is achieved by selecting initiators and regulators, distributing them in the main and side streams, and controlling temperature and pressure during polymerization. The resulting LDPE resin has good toughness, strength, and dimensional stability for food packaging cap applications.

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A degradable polyethylene packaging material that can decompose under certain conditions to reduce environmental pollution. The material is made by adding fillers like starch, sugar alcohols, and degradation accelerators like perborate to low-density polyethylene (LDPE). The fillers provide mechanical strength and the degradation accelerator promotes breakdown. This allows the material to decompose more easily compared to conventional LDPE. The degradability can be further enhanced by using specific isocyanates like hexamethylene diisocyanate or lysine methyl ester diisocyanate instead of conventional isocyanates.

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Laminate, packaging material, and package for hand-cut open packages that balances biodegradability and tear strength. The laminate has a specific layer order: substrate, adhesive, barrier, and sealant. The sealant layer contains both fossil fuel-derived linear low-density polyethylene (LLDPE) and plant-derived low-density polyethylene (LDPE) in a ratio of 3:7 to 7:3. This allows biodegradable content in the sealant while maintaining tear resistance and sealing strength. The barrier layer prevents tearing into the inner layers. The outermost sealant layer is LLDPE. The adhesive layer has low-density polyethylene. The substrate can be recycled or plant-based. The laminate allows hand cutting without scissors, drop impact resistance, and biodegradability

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A recyclable packaging material made from two layers, a surface layer and an inner layer, that adhere well together to prevent separation. The surface layer contains linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and metallocene linear low density polyethylene (MLLDPE) in specific weight ratios. The inner layer has low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) in certain ratios. The layers are joined by coating glue on one side of the surface layer and pressing it onto the inner layer. This prevents interlayer separation when opening the packaging.

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A packaging bag made from a composite thermoplastic material that improves durability and reduces contamination compared to conventional bags. The composite material is formed from specific ratios of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene polyethylene (mPE), chlorinated polyethylene (CE), and chlorosulfonated polyethylene (CSE). The optimized chlorine and sulfur contents in CE and CSE, respectively, enhance molecular chain entanglement and strength to prevent bag failure and reduce contamination.

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Packaging laminate with reduced environmental impact that maintains practical performance compared to traditional laminates. The laminate has a thin paper substrate with a resin layer made from a composition containing plant-derived low-density polyethylene (LDPE). The MFR (melt flow rate) of the resin composition is optimized to be 7.2 g/10min or less. This prevents deterioration of heat sealability when using plant-derived LDPE compared to conventional petroleum-based LDPE. The lower MFR keeps the resin flexibility while minimizing issues like seal integrity degradation.

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Low-temperature resistant polyethylene composition for injection molding packaging boxes that provides good low-temp performance without the high cost and processing issues of toughening agents. The composition contains 70-90% high-density polyethylene (HDPE), along with low-density polyethylene (LDPE) and/or linear low-density polyethylene (LLDPE). The specific physical property requirements for each type of PE are provided. By mixing the PE types directly, it allows uniform composition injection molding of low-temp resistant packaging boxes without the need for additional materials or processing steps.

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Polyethylene resin composition for films with improved tear properties for packaging applications. The composition contains a linear low density polyethylene (LLDPE) made with a metallocene catalyst, a low density polyethylene (LDPE) made with a metallocene catalyst, and ultra-low density polyethylene (ULDPE) made with a metallocene catalyst. The composition is prepared by melt-mixing the LLDPE, LDPE, and ULDPE in an extruder at temperatures of 150-230°C. The resulting composition provides films with excellent tear resistance, transparency, low temperature sealing, and mechanical properties.

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Polyethylene composition with improved barrier properties for packaging applications. The composition contains a specific blend of low-density polyethylene (LDPE) with a unique microstructure, along with other polyethylene components. The composition provides enhanced barrier to volatile substances like fragrances and pharmaceuticals compared to conventional LDPE. The barrier properties are attributed to the unique microstructure of the LDPE component. The composition can be prepared by melt blending the polyethylene components and molded into packaging products.

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Polyethylene composition with improved barrier properties for extrusion molded packaging applications, especially for packaging of food, medicine, and cosmetics. The composition contains specific types and ratios of linear low density polyethylene (LLDPE) resins to enhance barrier to volatile organic compounds. The composition includes LLDPEs with varying comonomer content, density, and melt index. The resins have microstructures that contribute to the improved barrier performance. The composition can also have minor amounts of other additives like terpene diene and antioxidants.

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Octene-modified linear low-density polyethylene (LLDPE) resin with improved transparency, shrinkage, and heat sealing properties compared to conventional LLDPE. The octene-LLDPE has a density of 0.917-0.923 g/cm3, melt index of 0.7-1.3 g/10min, octene unit content of 1.6-2.0 mol%, and molecular weight distribution melt flow ratio of 2.9-3.1. The octene modification improves properties like clarity, shrinkage, and tear resistance. The octene-LLDPE can be used in multi-layer co-extruded packaging films like heat shrinkable film. The octene-LLDPE is prepared by polymerization with octene monomer, catalysts like Ziegler-Natta catalyst

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Injection molded container with excellent injection moldability and crack resistance for pharmaceuticals, quasi-drugs, and cosmetics. The container is made from a specific blend of low density polyethylene (LDPE) with controlled melt flow rates and densities. The LDPE composition contains two types of LDPE with different melt flow rates. One type has a higher melt flow rate (70-150 g/10min) and the other has a lower melt flow rate (0.5-5 g/10min). This blend allows the container to have good injection moldability and flexibility while still having adequate thickness and length. The container also has good crack resistance due to the specific LDPE compositions.

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A lamination film for packaging materials like food that provides rigidity, shock resistance, and good heat-sealing properties. The film has two layers, a base layer and a sealing layer. The base layer has higher density and rigidity than the sealing layer. The base layer contains a copolymer of ethylene and an alpha olefin like propylene, along with low density polyethylene (LDPE) with long-chain branching. The sealing layer contains LDPE with short-chain branching. The film has a specific thickness ratio of the two layers. The base layer density is 0.006 g/cm³ less than the sealing layer density. The base layer and sealing layer thicknesses are in a range that balances rigidity and shock resistance.

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A polyethylene resin composition for extrusion lamination coating that provides improved heat resistance, adhesive strength, and molding balance compared to conventional compositions. The composition contains a specific combination of low density polyethylene (LDPE) and high density polyethylene (HDPE). The LDPE is made by copolymerization in an autoclave reactor followed by tubular reactor. The HDPE has a melt index of 15-25 g/10 min and density 0.955-0.965 g/cm3. The LDPE has a Z-average molecular weight of 400,000-700,000 and melt index of 5-10 g/10 min. This composition balances heat resistance, adhesion, and molding properties for extrusion lamination applications

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Paper packaging material for filling and packaging of liquid foods that has improved barrier properties, seal strength, and compatibility with liquid contents. The packaging material is a multilayer laminate with specific thermoplastic layers. The outer layer is a low-density polyethylene (LDPE) made from metallocene catalyst with narrow molecular weight distribution. The inner layer is also LDPE but with a wider molecular weight distribution. An intermediate adhesive layer connects the barrier layer (e.g., aluminum foil or inorganic oxide film) to the innermost LDPE layer. This configuration provides good barrier properties, seal strength, and compatibility with liquid foods compared to conventional packaging materials. The multilayer structure allows optimized sealing and conversion properties during manufacturing.

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Polyethylene film composition with improved properties like thermal bonding, impact strength, and transparency. The composition contains a specific linear low density polyethylene (LLDPE) mixed with low density polyethylene (LDPE) and a cyclic olefin resin. The LLDPE has a specific composition and molecular weight distribution. The composition is prepared by melt blending the LLDPE and LDPE in an extruder, then adding the cyclic olefin resin. This provides better film properties compared to blending the three components directly. The composition can be used to make films with wide widths at high speeds, good bubble stability, and high impact resistance.

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A polyethylene resin composition for injection molding that provides softness, impact resistance, environmental stress uniformity, and low migration in molded products like food containers and stoppers. The composition is made by melt blending 80-90% of a linear low density polyethylene (LLDPE) with 10-20% of an ethylene-α-olefin copolymer. The LLDPE has a melt flow rate of 15-30 dg/min and density of 0.915-0.930 g/cm3. The copolymer has a melt flow rate of 25-40 dg/min and density of 0.860-0.880 g/cm3. This blend provides optimal softness, impact, and environmental stress resistance compared to using just LLDPE or LLD

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Polyethylene composition for blown films with improved mechanical properties like impact strength and tear resistance. The composition contains linear low density polyethylene (LLDPE) with high MIF/MIE ratio (20 or more) and low density polyethylene (LDPE) with high molecular weight. The LDPE has a density of 0.910-0.93 g/cm3 and molecular weight of 0.1-0.4 g/10 min. The LLDPE has a density of 0.915-0.935 g/cm3 and MIF of 15-45 g/10 min. The composition balances impact strength and tear resistance in blown films.

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A polyethylene resin composition for a sealant film in flexible packaging that provides excellent film forming stability, transparency, and low temperature heat sealing properties. The composition contains a mixed resin of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE), along with a small amount of ultra low density polyethylene (ULDPE) prepared using a metallocene catalyst. The composition ratios are optimized to balance film properties.

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High transparent polyethylene composition for packaging applications that has improved properties like clarity, strength, and toughness compared to conventional polyethylene. The composition contains a blend of linear low density polyethylene (LLDPE) resins, including a first LLDPE with specific properties, and a second LLDPE. The blending of the two LLDPE resins with different characteristics improves the overall properties of the polyethylene composition. The composition also contains processing aids like slip agents and antioxidants.

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