HDPE Closure Composition Eliminating Inner Liners
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Solution Overview
Problem
Current polymer formulations for closure devices, such as bottle caps, require inner liners for strength and seal, increasing costs and complexity, while lacking in stress crack resistance, impact strength, and taste/odor neutrality.
Innovation Solution
A high-density polyethylene composition comprising a high molecular weight ethylene alpha-olefin copolymer and a low molecular weight ethylene polymer, produced through a dual-reactor process, offering improved density, melt index, and environmental stress crack resistance, eliminating the need for inner liners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a two-part construction with inner liner is used, then strength and seal are improved, but cost and complexity increase
Solution Approach 1:
The patent combines the functions of the rigid cap body and the soft sealing liner into a single integrated polyethylene component. The composition creates a one-piece closure device where the polyethylene material simultaneously provides structural strength and sealing capability, eliminating the need for separate inner liner components and reducing assembly complexity.
Solution Approach 2:
The patent employs a composite polymer composition consisting of high-density polyethylene blended with specific elastomeric additives. This composite material integrates the rigidity and strength of HDPE with the flexibility and sealability of elastomers, creating a single-material solution that replaces the traditional multi-material two-part construction.
2Strength
If high-density polyethylene is used, then density and structural strength are improved, but environmental stress crack resistance deteriorates
Solution Approach 1:
The patent modifies the physical and chemical parameters of polyethylene by blending it with elastomeric components and controlling molecular weight distribution. This parameter adjustment maintains the high density and structural strength of HDPE while introducing flexibility that significantly improves environmental stress crack resistance, achieving a balance between strength and reliability.
3Strength
If polypropylene is used for closure devices, then strength is improved, but taste and odor neutrality deteriorates
Solution Approach 1:
The patent uses a homogeneous polyethylene-based composition that is inherently free from the taste and odor issues associated with polypropylene. The uniform polyethylene matrix ensures consistent chemical inertness and neutrality, eliminating the harmful factors while maintaining adequate strength through proper formulation and processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition provides a one-piece closure device with enhanced strength, impact resistance, and environmental stress crack resistance, ensuring effective sealing and taste/odor neutrality, reducing production costs and complexity.
Implementation Method 1
polymerizing the additional ethylene in the second reactor thereby producing a second component
Implementation Method 2
The extruder conveys, heats, melts, and pressurizes the molding compound to a form a molten stream
Implementation Method 3
The extruder conveys, heats, melts, and pressurizes the molding compound to a form a molten stream
Implementation Method 4
The melt cools and hardens until fully set-up
Implementation Method 5
The melt cools and hardens until fully set-up
Data Source
AI summary
The instant invention is a high-density polyethylene composition, method of producing the same, articles made therefrom, and method of making such articles. The high-density polyethylene composition of the instant invention includes a first component, and a second component. The first component is a high molecular weight ethylene alpha-olefin copolymer having a density in the range of 0.915 to 0.940 g/cm3, and a melt index (I21.6) in the range of 0.5 to 10 g/10 minutes. The second component is a low molecular weight ethylene polymer having a density in the range of 0.965 to 0.980 g/cm3, and a melt index (I2) in the range of 50 to 1500 g/10 minutes. The high-density polyethylene composition has a melt index (I2) of at least 1, a density in the range of 0.950 to 0.960 g/cm3, and g′ of 1.