Developments in Low-Density Polyethylene for Packaging

Retortable packaging film for food products that is recyclable and provides good sealing and tear properties for retort processing. The film uses a mono-polymer laminate of biaxially oriented polypropylene (BOPP) and machine direction oriented polypropylene (MDOPP) instead of multipolymer laminates. A sealing layer with specific polypropylene terpolymer and long-chain branched polyethylene composition provides sealing strength and low melt flow index for retort compatibility. The film has at least 80% polypropylene content.

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<Packaging material> The present invention also relates to a packaging material including the multilayer film described above. The packaging material is, for example, a packaging bag for packaging heavy items, such as fertilizers, grains, and resin pellets.

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Bottle closure assembly with a tethered cap that provides improved retention when the cap is removed. The assembly has a cap, tether, and retaining means. The cap covers the bottle opening, the tether connects the cap to the retaining means, and the retaining means attaches to the bottle. The cap, tether, and retaining means are made from a polyethylene composition with specific properties for good processability, organoleptic properties, dimensional stability, and stress crack resistance. The composition has a low melt index (<10 g/10 min), a high density first ethylene copolymer (0.920-0.960 g/cm3), and a lower density second ethylene copolymer (>0.960 g/cm3). The ratio of short chain branches in the first copolymer vs the second copolymer is

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Resin composition, film, laminated film, and packaging material with improved balance between easy-opening properties and low-temperature heat sealability. The composition contains 5-30% of a butene polymer, 30-55% high-pressure LDPE, and 30-45% ethylene-α-olefin copolymer with specific properties. The mass ratio of LDPE to copolymer is 40:60 to 59:41. The butene polymer has a melting point of 100-130°C, low melt flow rate, and high proportion of low molecular weight components. The composition provides a film with good easy-opening and low-temp sealability over a wide temperature range.

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A film for packaging materials that has low contamination properties when stored rolled. The film contains an ethylene-based polymer that meets specific requirements: melt flow rate of 0.01 to 10 g/10 min at 190°C, density of 0.930 to 0.945 g/cm3, molecular weight distribution (MWD) of 2.0 to 3.0, and elongation at break of 200% to 400%. This film can be used as a base material for packaging that avoids contamination issues when stored rolled. The film is made by stretching an ethylene-based polymer with the specified properties.

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Polyethylene laminate film for packaging applications with improved heat resistance and sealing performance. The laminate film has an inner surface layer made of a specific ethylene polymer composition, sandwiched between outer layers. The inner layer composition allows good heat resistance for high-speed packaging machines. The outer layers provide mechanical strength and sealability. The film structure enables balanced properties for packaging applications like vertical form fill seal (VFFS) machines. The laminate film can replace pure polyethylene films for sustainable packaging by eliminating different resin types.

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Packaging material for fixing and cushioning objects inside cardboard boxes, suitable for a wide range of object sizes and shapes. The packaging material consists of overlapped film sheets with air passages and cells. The cells have vertical rods shaped like letters "L" and "S". The long rods have bent bottoms that touch the box walls. Short rods on either side are slightly shorter than the box height. Inflating the cells expands the rods to surround and fix the object. Check valves allow venting. This versatile packaging can cushion and position objects of different sizes and shapes without molds.

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Cushioning material and packaging box that can pack objects without separate padding while protecting during shipping. The cushioning material has sections that bend and interconnect to create spaces for object containment and impact absorption. The cushioning sections form a flexible network inside the packaging box. It eliminates the need for separate padding inserts and reduces waste compared to separate padding. The interconnected cushioning sections bend and deform as the object moves during transport to absorb impacts. The cushioning sections are designed with curved lines that slope upward or downward at certain points to enable this flexing and buffer the object inside.

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Packaging bag for liquid contents that can be easily opened and poured without contamination. The bag has three chambers - a main storage chamber, and two smaller chambers branching off above it. The branching film dividing the chambers is folded in half. The chambers are sealed by overlapping and sealing the films. An easily peelable isolation seal line separates the storage chamber from the branch chambers. This allows the smaller chambers to be torn off and poured without contaminating the main chamber contents. The isolation seal line can be formed by easily peelable sections on the front and rear films that overlap the branching film.

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Retortable packaging film for food that is recyclable, robust enough for retort processing, and has straight tear properties without visible scores. The film has a mono-polymer laminate of BOPP and MDOPP films, with an extrusion-coated sealing layer containing blended polypropylene terpolymer and long-chain branched polyethylene. The sealing layer has a low melt flow index of 5-25 g/10 min for heat sealing. The total film composition is 80%+ polypropylene. This allows recycling compliance, high heat resistance, and good sealing.

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Bottle closure assembly with a tethered cap that has improved processability, organoleptic properties, dimensional stability and stress crack resistance compared to traditional bottle closures. The closure is made from a polyethylene composition containing specific ethylene copolymers with controlled branching ratios. The copolymers have melt indexes below 10 g/10min and densities between 0.920 and 0.960 g/cm3. The closure has an integrally molded cap, tether, and retaining portion. The tether connects the cap to the retaining portion and breaks when the cap is removed, preventing loss. This allows tethered closure designs without molding complex flow paths. The copolymer composition enables good closure performance and processability for tethered closures.

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Packaging bags for sheets like paper towels that reduce plastic content while preventing tearing during use. The bags are made from a laminate containing paper and a resin layer. The resin layer has a first layer of branched low-density polyethylene (LDPE) on the paper side and a second layer of polyolefin with higher impact strength on the opposite side. This provides a second protective layer to prevent tearing when lifting or removing the sheet without adding excessive plastic. The second layer thickness is 4-22 microns, the ratio to the first layer is 0.2-0.8, and the overall paper content is 50% or more to minimize plastic use.

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A packaging paper for hygiene products that is environmentally friendly and provides better sealing compared to existing papers. The paper has a structure with layers starting from the content side: a release layer, a heat-sealing layer, a paper base, and another heat-sealing layer. The release layer prevents the heat-sealing layer from sticking to the content. The sealing layers are made with specific materials like branched polyethylene wax or acrylic acid grafted branched polyethylene wax. This allows better sealing compared to traditional PE film packaging. The paper is produced by coating the layers onto a paper base.

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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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Ethylene-based resin composition for packaging films that provides excellent heat-sealability and heat resistance over a wide temperature range. The composition has specific properties like low density, elution fractionation curve, and melt flow rate. It contains an ethylene copolymer (B) and a low melt point ethylene resin (C) made by radical polymerization. This allows good sealing with thin layers at low temperatures. The composition can also have a high-pressure LDPE (D) for further sealing properties. The laminate film has 3 layers with the intermediate layer containing B and the sealant layer containing B and C.

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Multilayer film, laminated film, and packaging material for improving sealing properties, easy openability, and visibility of release marks after peeling off the lid. The film has a heat-sealing layer with a specific composition of high-density polyethylene (HDPE), propylene random copolymer, and 1-butene polymer. This composition provides good adhesion, sealing strength, and cohesive failure when peeling the lid off. It also enables the release mark to have high visibility due to the phase structure of dispersed incompatible components. The film can be laminated with a substrate layer for packaging applications.

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Stretched polyethylene film with improved properties for use in monomaterial packaging. The film is made by stretching a polyethylene resin composition that meets specific density, molecular weight, and branching requirements. The stretched film has good balance between rigidity and impact strength. It can be used as a base film in monomaterial packaging where both the base and sealant films are made of polyethylene. This allows recycling of the packaging material as pure polyethylene.

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Recyclable packaging material that improves clarity and recyclability compared to traditional packaging films. The material contains a major portion of high-density polyethylene (HDPE) or medium-density polyethylene (MDPE) with specific properties. It has a young's modulus less than 700 MPa and a haze value less than or equal to 50%. This provides a softer, more flexible material with better clarity compared to high-density LDPE blends. The HDPE/MDPE based films can be prepared using a downward blown film process. This allows recycling the material in HDPE streams without loss of clarity. The HDPE/MDPE content also improves recyclability compared to blends with low-density polyethylene (LDPE).

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Bottle closure assembly with an integrated tether that prevents loss of the cap when removed from a bottle. The assembly comprises a cap, tether, and retaining portion all made from a polyethylene composition with specific properties. The polyethylene has a low melt index (less than 1.0 g/10min), high short chain branch density (0.920-0.960 g/cm3), and high short chain branch ratio (>0.5) to enable good processability and stress crack resistance. The high density ethylene copolymer (20-10000 g/10min) provides strength. This allows complex molded shapes like the tether that connects the cap to the bottle. The polyethylene composition has elongation at break >600%, tensile strength >20 MPa, and melt index 0

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Multilayer films for packaging applications that provide consistent and conformable opening forces when incorporated into packages. The films have a sealant layer with at least 30% low density polyethylene (LDPE) to provide delamination opening when sealed. This prevents tearing and allows peeling open of packages like bags. The LDPE-rich sealant layer delaminates within the film instead of adhesively sealing. The films can be used in packages like bags that delaminate open when sealed, providing uniform and adaptable opening forces.

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