Plastic Preform Neck Finish Weight Reduction
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Solution Overview
Problem
Existing heat sealable neck finishes for thermoplastic containers are heavy due to thick walls required for mechanical resistance during heat welding, which increases weight without providing a significant reduction in mechanical strength or ease of handling.
Innovation Solution
A plastic preform with a novel heat sealable neck finish comprising a first upper heat sealable portion, a second intermediate threaded portion, and a third lower portion with a neck support ring, featuring an annular gripping recess and an inward transition step that reduces the outer diameter below the neck support ring, allowing for weight reduction without compromising mechanical resistance or ease of handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall thickness of the neck finish is increased to withstand mechanical top load during heat welding, then the mechanical strength is improved, but the weight of the neck finish increases
Solution Approach 1:
The patent applies local quality by creating a neck support ring with increased wall thickness specifically in the region where mechanical support is needed during heat welding, while keeping other portions of the container wall thinner. This localized thickening provides the necessary mechanical strength at the critical neck finish area without increasing the overall weight of the container.
Solution Approach 2:
The neck finish is segmented into distinct functional zones: a neck support ring with enhanced thickness for mechanical support, a heat sealable portion for sealing operations, and a threaded portion for closure attachment. This segmentation allows each zone to be optimized for its specific function, with the support ring bearing the mechanical load while other zones remain lightweight.
2Weight of moving object
If the outer diameter of the neck finish is reduced to lower weight, then the weight is decreased, but the ease of handling and gripping becomes difficult
Solution Approach 1:
The patent solves the gripping problem by adding vertical dimensionality through an annular gripping recess that creates a stepped configuration. This recess provides a finger engagement surface at a different vertical level, allowing effective gripping without increasing the horizontal outer diameter of the neck finish.
Solution Approach 2:
The annular gripping recess acts as an intermediary feature between the user's finger and the neck finish surface. It provides a dedicated engagement zone that facilitates easy gripping and handling while maintaining a compact overall diameter, serving as a mediator that resolves the conflict between size and handleability.
3Stability of the object's composition
If the neck support ring width is increased to maintain preform stability during biaxial stretching, then the stability is improved, but the weight of the neck finish increases
Solution Approach 1:
The patent optimizes the neck support ring by carefully controlling its dimensional parameters - specifically maintaining a width L1 between 0.5mm and 2mm and a height H1 between 1mm and 3mm. These parameter changes allow the ring to provide sufficient stability during biaxial stretching while minimizing material usage and overall weight.
Solution Approach 2:
The neck support ring is formed as an integrated composite structure combining the neck finish material with the container body material during injection molding. This composite construction provides enhanced mechanical stability during stretching operations while utilizing the material properties of the thermoplastic resin to achieve the required strength-to-weight ratio.
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 solution enables a lighter weight neck finish that maintains mechanical resistance to top loads and can be easily gripped, facilitating biaxial stretching to form a container of higher volume while allowing for efficient sealing with a heat welded foil.
Implementation Method 1
The heat welding operation of the sealing foil onto the container is performed by heating the sealing foil in such a way that the heat weldable layer is melted
Implementation Method 2
A heat weldable sealing foil generally comprises at least two laminated layers: a thermal conductive layer, and a heat weldable layer
Data Source
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AI summary
The plastic preform (1) comprises a heat sealable neck finish (2) having at least a first upper heat sealable portion (20) which is terminated by a top opened end (200), a second intermediate threaded portion (21) for screwing a closure cap, and a third lower portion (22) that comprises a neck support ring (221a) of width (L1). The first upper portion (20) comprises an annular gripping recess (201) of predetermined height (H2) and depth (d). The inner face of the third lower portion (22) forms an inward transition step (221 b), and the outer diameter (D3) of the preform measured just below the neck support ring (221a) is less than the outer diameter (D2) of the neck finish measured just above the said inward transition step (221b).