Developments in Polyethylene for High-Performance Packaging

Polypropylene-based packaging material with improved drop impact resistance, blocking resistance, slipperiness, and flavor barrier properties for food packaging applications. The packaging material contains an ethylene-propylene block copolymer with a unique phase dispersion structure. The copolymer has a matrix of propylene-based polymer and spindle-shaped domains made of propylene-based elastomer. The spindle shape provides optimal properties like drop impact resistance, blocking resistance, and slipperiness while avoiding issues like poor flavor barrier or appearance.

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Food contact material compositions with improved stiffness, barrier properties, thermoformability, and optical properties for food packaging applications. The compositions contain polypropylene, a hydrocarbon resin, and optionally additives like nucleating agents. The polypropylene is a blend of two types, one with low melt flow rate and one with high melt flow rate. This combination provides high stiffness, clarity, and processability while reducing shrinkage compared to using a single polypropylene. The hydrocarbon resin further enhances stiffness. The resulting compositions can have desirable properties like high stiffness, low shrinkage, low water vapor transmission, low oxygen transmission, high impact strength, and high clarity for food packaging applications.

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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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Food contact materials (FCMs) with improved properties for food packaging applications. The FCMs contain a combination of polypropylene resins with different molecular weights, along with a small amount of hydrocarbon resin. This composition provides high stiffness, snappability, barrier properties, thermoformability, and optical properties for food packaging while maintaining clarity. The FCMs can have properties like tensile modulus >2.5 GPa, water vapor transmission rate <0.005 g/100 in2/48 hr, and oxygen transmission rate <0.07 cc/pkg/24 hr.

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Packaging film with a low gloss suitable for products like pet food, cereals, and healthcare items. The film has a coextruded layer structure with a first layer containing 5-30% cyclic olefin copolymer (COC) and 70-95% polyolefin. This provides a gloss of <=50% while the COC's higher glass transition temperature improves thermal resistance. The film can be recyclable, have better recyclate quality, and better stiffness compared to conventional films with matte coatings or micron-sized inorganics. The film can be blown or cast oriented, have a barrier layer, and have printed indicia.

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Polyolefin packaging material that is fully recyclable and reusable without special separation steps. The packaging uses a polyolefin bonding adhesive layer made from a modified copolymer of C2-C4 olefins like ethylene and butylene. The copolymer is grafted with maleic anhydride at a ratio of 0.5-5%. This adhesive layer bonds two polyolefin films, like a cast polypropylene and an oriented polypropylene, to create a packaging material that can be directly recycled and reused without separating layers. The modified adhesive provides good bonding strength, transparency, and impact resistance.

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Recyclable flexible packaging film made of similar materials to enable recycling without solvent inks. The film has a crosslinked polyethylene substrate layer made by electron beam treatment, followed by stretching. This is laminated with a sealant polyethylene layer using an adhesive. The crosslinking improves heat resistance and recyclability compared to untreated polyethylene. The thicknesses of the crosslinked layer, adhesive, and sealant are optimized for recyclability. The monolayer and multilayer film structure allows recycling by pelletizing since all layers are the same polyethylene.

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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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Recycling of polyethylene terephthalate (PET) bottles into high quality, food-grade PET pellets that can be used to make new bottles. The recycling process involves reprocessing the PET flakes from post-consumer bottles to increase molecular weight, intrinsic viscosity, and color quality. This is achieved through controlled extrusion and solid-state polymerization steps. Chain extenders and anti-yellowing agents are added during extrusion. The extruded pellets are then treated by solid-state polymerization to further improve molecular weight and color. The resulting recycled PET pellets have average molecular weight above 40,000 Da, intrinsic viscosity around 0.7-0.9 dl/g, and color deviation under 2.5.

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Co-extruded multi-layer polymeric films for packaging flowable products like food and beverages. The films have a unique structure with an inner sealant layer, outer sealant layer, and a thin barrier core layer sandwiched between. The sealant layers are high-density ethylene-alpha-olefin copolymers. The barrier layer is a low-density ethylene-vinyl alcohol copolymer with high ethylene content. This provides good barrier, toughness, and flexibility while maintaining recyclability. The films can be used in bags for flowable products that require refrigeration without leakage or emptying issues.

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Polypropylene film with improved thermal stability and barrier properties for packaging applications. The film has a unique combination of properties that addresses issues with pinholes and cracks in transparent vapor deposited layers on polypropylene. It has a film thickness x multiplied by F5 value in the perpendicular direction less than 2000 N/m, and thermal shrinkage delta less than 2.00 in the perpendicular direction and less than 2.50 in the parallel direction at 100 and 130 degrees Celsius. This prevents excessive shrinkage during processing and heat sterilization that can cause defects. The film also has a low Sku value on at least one surface below 300. The film's improved thermal stability allows reliable formation of thin transparent vapor deposited layers without pinholes and cracks, and prevents defects during heat

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Gas barrier film for packaging applications that provides a mono-material packaging solution while maintaining strong adhesion between layers. The film has a base material made of stretched polyethylene with a low probe descent temperature (around 170°C) to enhance adhesion to the heat seal layer. An inorganic oxide layer or oxygen barrier membrane is formed on the base material surface. The film can be used in a laminate structure with another polyethylene layer joined by adhesive. The low probe descent temperature base material enables strong adhesion between the layers without delamination.

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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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A stable void-fill packaging material made from a blend of recycled and virgin polyethylene that provides consistent transparency and bubble stability for automated packaging processes. The blend contains at least 50% recycled polyethylene and at least 40% virgin polyethylene, along with moisture scavengers and melt stabilizers to prevent voids and inconsistencies in the film. The recycled and virgin polymers are blended to balance properties like tear strength, impact resistance, and transparency.

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Mono-material containers made entirely from a single foam material, such as polylactic acid (PLA), for improved recyclability and reduced waste compared to containers made from different materials that require adhesives to join. The containers are formed by joining together multiple portions of PLA foam without adhesives to create a container made entirely from the same foam material. This allows the container to be fully recycled as the same material can be easily identified and separated during recycling. The containers can be used for applications like insulated shipping containers, food packaging, and protective packaging.

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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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A mono-material stand-up pouch packaging bag that can be easily recycled since it uses only one type of polyethylene resin for the bag material instead of multiple layers like in conventional bags. The bag has a unique bottom seal design with a convex shape near the connections to the side seals. This shape distributes stress from the bag contents more evenly to prevent concentration at the corners and improve impact resistance. The convex shape also allows the bottom to expand more on the side above the fold line to disperse content loading force.

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Multilayer packaging material for retort foods that can be recycled after retorting. The structure has an outer and inner polypropylene layer sandwiched between an EVOH barrier layer and an aluminum foil layer. The total thickness is 200 microns or less. This allows good gas barrier and shading after retorting while still being recyclable. The key is using specific polypropylene melting points, EVOH saponification and aluminum thickness to balance properties and avoid issues during recycling.

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Polyethylene-based resin composition and packaging material that has improved moldability, bag-making processability, and film strength when inorganic compounds like calcium carbonate are added. The composition contains an ethylene-α-olefin copolymer with specific properties and an inorganic compound like calcium carbonate. The ethylene-α-olefin copolymer has 6-8 carbon α-olefin units, a melt flow rate of 0.8-4.0 g/10 min, and a melting point of 90-130°C. The inorganic compound content is 50-80% by mass and the copolymer content is 10-50% by mass. This composition enables better film properties when inorganic compounds are added compared to conventional compositions.

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