Hinged Component Polyethylene Composition Hinge Life
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Solution Overview
Problem
Existing polyethylene compositions for hinged components, such as bottle closures, do not provide optimal hinge life cycle values, as they lack the necessary balance of properties like molecular weight distribution, density, and melt index to ensure durability and performance.
Innovation Solution
A polyethylene composition comprising a first ethylene copolymer with a specific molecular weight distribution, density, and melt index, combined with a second ethylene copolymer, optimized for short chain branching and density, is used to create hinged components with improved hinge life cycle values through compression molding or injection molding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional polyethylene compositions are used for hinged components, then manufacturing is simpler, but hinge life cycle values are insufficient
Solution Approach 1:
The patent applies composite materials by blending two distinct polyethylene components (first and second polyethylene) with specific molecular weight distributions and densities to create a composite polyethylene composition. This composite structure provides optimized hinge life cycle performance (greater than 4200 cycles) while maintaining manufacturability through injection molding or compression molding processes.
Solution Approach 2:
The patent implements parameter changes by precisely controlling key parameters of the polyethylene composition including molecular weight distribution (Mw/Mn ratios of 2.0-7.0 and 3.0-8.0), densities (0.910-0.940 g/cm³ and 0.930-0.960 g/cm³), and melt indices (0.1-10 g/10min and 10-100 g/10min). These parameter optimizations enable the hinged component to achieve over 4200 hinge life cycles while remaining compatible with standard manufacturing processes.
2Duration of action of moving object
If polyethylene composition with optimized molecular weight distribution and density is used, then hinge life is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses manufacturing precision requirements by specifying concrete parameter ranges that balance performance and manufacturability. The molecular weight distribution is controlled within Mw/Mn ratios of 2.0-7.0 for the first polyethylene and 3.0-8.0 for the second polyethylene, with densities of 0.910-0.940 g/cm³ and 0.930-0.960 g/cm³ respectively. These defined ranges enable achievement of greater than 4200 hinge life cycles while remaining compatible with standard injection molding and compression molding processes.
Data Source
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AI summary
A hinged component comprising a polyethylene composition having a molecular weight distribution Mw/Mn, of from 2.0 to 7.0; a density of at least 0.949 g/cm3; a melt index, I2 of from greater than 10.0 g/10min to 20.0 g/10min, a Z- average molecular weight MZ, of less than 300,000; and a melt flow ratio I21/I2, of from 24 to 38; where the hinged component has an average hinge life of more than 4100 cycles.