Developments in Medium-Density Polyethylene for Packaging

Polymeric film, sheet, and wrapper with dead fold characteristics that allows folding, twisting, and reclosing without using adhesives. The structure has multiple layers of low and high density polyethylene (LDPE and HDPE) sandwiched with cyclic olefin copolymer (COC) or ethylene vinyl alcohol (EVOH) barrier layers. This provides barrier properties, tear resistance, and dead folding ability. The outer LDPE layer can have printed inks and sealant coating. The dead folding allows folding the wrapper shut after opening without needing adhesives.

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Connective protective packaging that can stick to itself or other surfaces to better encase and secure packaged items. The packaging has a reconfigurable body that goes from a high-density supply configuration to a low-density cushioning configuration. In the low-density configuration, an exposed surface has a bonding element like an adhesive or cohesive. Folding the packaging over itself with the bonding element contacting another surface connects them. This allows the packaging to stick to itself or other surfaces to form pockets or better containment around items.

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Laminate structures for flexible packaging that provide both recyclability and mechanical strength. The laminate comprises a uniaxially oriented first multilayer film made from ethylene-based polymer with specific density and melt index. The film is oriented at a ratio of 3:1 to 8:1 in the machine direction. The first film has higher elongation in the cross direction compared to machine direction. This is combined with a biaxially oriented second multilayer film made from ethylene-based polymer with higher density. The second film has higher draw ratio in the cross direction. The laminate structure balances recyclability from the ethylene-based polymers with improved mechanical properties from the oriented films.

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Co-extruded multilayer films for packaging flowable products like food and beverages that provide improved toughness, barrier properties, and recyclability compared to existing films. The films have layers with specific ethylene/alpha-olefin copolymer densities, barrier EVOH layers, and adhesives. The inner and outer sealant layers have 50%+ ethylene copolymer with densities 0.910-0.924 g/cm3. The EVOH barrier layer is 0.1-5% thickness. This structure provides good barrier, flex-crack resistance, and toughness while being recyclable.

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Recyclable polyethylene-based packaging material with improved openability and a method for making it. The packaging material uses a multi-layered polyethylene film with specific properties to balance tear strength, heat sealing, and recyclability. The outer layer has a melting point of 128°C or higher for tear resistance. The innermost layer melts at 103°C or lower for heat sealing. The layers in between have intermediate densities. This allows easy opening and recycling without melting during processing. It also prevents leakage at low temps due to cracks. The multi-layered structure provides mechanical strength and processability while maintaining recyclability compared to laminated films.

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Polyethylene film with improved low-temperature durability for packaging applications. The film has a multi-layer structure with specific density and thickness ratios between the outer, middle, and inner layers. The densities range from 0.935 to 0.968, 0.900 to 0.920, and 0.850 to 0.905 respectively. The thickness ratios are 1:1 to 10:0.5 to 2. The film also has balanced falling ball impact strength and puncture strength in the range of 3.0 to 15.0 g/μm and 0.2 to 0.4 N/μm respectively. The melting point difference between the outer and inner layers is 30 to 100°C. This film composition provides excellent low-temperature durability

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Propylene-ethylene random copolymer compositions for hot fill packaging of food and beverages that provide good stiffness, heat resistance, and transparency. The copolymers have propylene as the primary monomer with 2-6 wt% ethylene, melt flow rates >1 g/10 min, and xylene solubles <7 wt%. They are produced using a Ziegler-Natta catalyst and alkoxysilane electron donor.

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Packaging laminate for food products that meets USDA and FDA requirements for extending shelf life, being recyclable, and having high barrier properties. The laminate has two or more layers of polyolefins like HDPE, LDPE, LLDPE, and PP. The outer layer is a printable HDPE with calcium carbonate. The inner layer is HDPE, LLDPE, and LDPE with an EVOH barrier and compatibilizer. This allows sealing, recyclability, and barrier properties for food packaging. The laminate can also have a middle HDPE layer.

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Propylene-ethylene random copolymer compositions for hot fill packaging applications like containers and films for food and beverage packaging. The compositions have propylene as the main monomer, ethylene content around 3-5%, melt flow rates 1-100 g/10 min, and xylene solubles less than 7%. The copolymers are produced using Ziegler-Natta catalysts with alkoxysilane electron donors. The compositions have good stiffness, heat resistance, and transparency for hot filling and sealing food containers.

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A specific multilayer mono-material PE assembly for packaging applications that is environmentally sustainable, recyclable, and provides durability, versatility, lightness, gas and moisture barrier, chemical resistance, and adhesion without adhesives. The assembly has at least two layers of high-density PE (HDPE) and a middle layer of PE blend with lower melting temperature. The HDPE layer prevents softening during sealing, and the lower melting blend layer allows adhesion. This enables recyclability without adhesives while maintaining performance during packaging steps. The HDPE density is 0.935-0.951 g/cm3 and the blend density is 0.911-0.924 g/cm3. The blend composition can vary. The assembly can have additional layers like printed, varnish, metallization, EVOH, or gas barrier coatings

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Multilayer packaging structure for snack food applications like potato chips that provides better sealing, hot tack, and faster machine speed compared to current structures. The structure has a sealant layer with a blend of ethylene/α-olefin copolymers and high density polyethylene. The copolymer blend has a density of 0.85-0.94 g/cc and melt index of 1.0-6.0 g/10 min. The high density polyethylene has a density of 0.916 g/cc and bimodal molecular weight distribution. The sealant layer coating weight is at least 8 gsm. This blend provides good sealing properties, hot tack, and faster machine performance compared to conventional mLLDPE sealants.

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Polyethylene-based resin composition for packaging materials that balances moldability, bag-making processability, and film strength when inorganic compounds like calcium carbonate are added. The composition contains a specific ratio of an ethylene-α-olefin copolymer A polymerized with a metallocene-based catalyst. This copolymer, along with a resin component, provides the desired properties when the resin component makes up 25-90% of the total composition.

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Recyclable polyethylene film for large bags that replaces PET in current laminates to improve recyclability. The film has a core layer sandwiched between tie layers. The core contains olefin block copolymer, low density PE, and high density PE. The tie layers have high density PE and low density PE. This composition provides good drop resistance similar to PET/PET laminates but with all PE for recyclability. The film can be oriented for strength.

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Resin laminate, packaging containers, and a production method for the laminate without adhesives or coatings. The laminate has layers with oxidized surfaces and uses low density polyethylene (LDPE) with density 0.850-0.915 g/cm3 for the intermediate layer. The LDPE density range ensures good peel strength without adhesives. The outer layers can be thermoplastic resins or cellophane. The production method involves plasma treating the outer layer surfaces, sandwching molten LDPE between them, and continuously laminating with ozone treated molten LDPE. This provides peel strength without adhesives or coatings.

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Bottle closure assemblies with improved stress crack resistance and dimensional stability for long flow path molding processes like tethered closures. The closure components are made from a polyethylene composition with specific ethylene copolymer ratios. It contains 10-70 wt % of a low melt index copolymer (Mi ≤ 10 g/10 min) with density 0.920-0.960 g/cm3, and 90-30 wt % of a higher Mi copolymer (Mi ≥ 50 g/10 min) with density higher than the first copolymer but less than 0.970 g/cm3. The ratio of short chain branch density in the two copolymers (SCB1/SCB2) is >0.5. This polyethylene composition

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Recyclable packaging material with improved clarity, stiffness, and recyclability compared to existing packaging films. The material contains 50-90 wt% of high-density or medium-density polyethylene (HDPE/MDPE) with a density of 0.94-0.97 g/cm3. This HDPE/MDPE-rich material has lower Young's modulus (stiffness) of less than 700 MPa and lower haze (clarity) of less than 50%. The reduced barrier layer content also enables recyclability in specific codes without loss of clarity. The material is made by downward extrusion instead of upward extrusion for improved clarity.

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Multi-layer films for bags used to package flowable liquids like dairy products that have improved toughness and seal strength, especially under refrigerated conditions. The films have an outer and inner sealant layer containing an ethylene/α-olefin interpolymer, with optionally an intermediate layer between them also containing the interpolymer. This composition improves bag performance when filled with chilled liquids compared to conventional films. The interpolymer composition has specific properties like density and melt index.

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Stable void-fill packaging film made with a mixture of recycled and virgin polyethylene resins, moisture scavengers, and melt stabilizers to overcome inconsistencies in recycled resins that affect packaging performance. The film composition contains at least 50% recycled polyethylene, at least 40% virgin polyethylene, a moisture scavenger like calcium oxide, and a melt stabilizer like elastomeric polyolefin. This stabilized recycled polymer blend provides consistent film properties like transparency, bubble stability, and drawdown for void-fill packaging applications. The scavenger removes moisture during extrusion to prevent voids in the film, and the stabilizer improves melt strength and processability. The film can be blown into pillow shapes for cushioning and packaging applications.

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Monomaterial polyethylene multilayer films and laminates for flexible packaging that improve forming speeds while maintaining recyclability. The films have a specific composition and layer structure. The outer surface layer contains an ethylene polymer with high comonomer distribution index (MWCDI>0.9) and high melt index ratio (I10/I2>7.0-1.2*log(I2)) to provide strength and thermal resistance during fabrication. The intermediate layer has the same polymer. The outer layer also has a lower density (0.890-0.925 g/cc) polymer with lower melt index (0.2-2.0 g/10 min) for stiffness. This allows higher forming speeds compared to monolayer PE. The combination of high MWCDI and high melt index ratio in the outer layer, plus the intermediate layer, provides thermal

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A multi-layer film for bags used to package liquid flowable materials like dairy products. The film has an outer and inner sealant layer containing an ethylene/α-olefin interpolymer, an intermediate layer of the same interpolymer, and a core layer of polyethylene or other polyolefin. The interpolymer provides toughness and seal strength while the core layer provides strength and puncture resistance.

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