Refillable Plastic Container Neck Geometry for Alkaline Cleaning Durability
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Solution Overview
Problem
Plastic containers, particularly those made of PET or PEF, suffer from stress-induced issues such as microcracks and leaks due to unstretched neck regions during cleaning with alkaline solutions, which can lead to degradation and failure over time.
Innovation Solution
A refillable plastic container design with a shorter axial neck length, thicker wall thickness, and optimized geometric features, along with a closure cap system, minimizes production stresses and enhances durability for multiple cleanings and refilling cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the neck region is left unstretched during production, then the production process is simpler, but stress-induced microcracks and leaks occur during cleaning with alkaline solutions
Solution Approach 1:
The patent applies parameter changes by modifying the neck region's geometric parameters (length, wall thickness, curvature radius) to reduce stress concentration. Specifically, the neck length is limited to 17.25 mm or less, wall thickness is increased to at least 1.9 mm, and curvature radius is optimized to minimize stress during alkaline cleaning while maintaining production simplicity
2Reliability
If the neck wall thickness is increased to prevent microcracks, then durability improves, but material consumption and production costs increase
Solution Approach 1:
The patent applies local quality by concentrating the increased wall thickness specifically in the neck region where stress concentration occurs during cleaning, while the rest of the container body maintains standard wall thickness. This localized reinforcement provides the necessary durability for multiple cleanings without unnecessarily increasing overall material consumption
3Reliability
If the neck axial length is reduced to minimize stresses, then resistance to thermal and mechanical stresses improves, but the closure cap fitting space is reduced
Solution Approach 1:
The patent applies parameter changes by precisely optimizing the neck axial length to 17.25 mm or less, which minimizes stress during thermal and mechanical processing while maintaining sufficient space for closure cap fitting. This specific parameter threshold balances stress reduction with functional requirements
4Duration of action of stationary object
If the container is designed for multiple refilling cycles, then sustainability and economic value improve, but the container must withstand repeated cleaning with alkaline solutions which causes degradation
Solution Approach 1:
The patent applies parameter changes by optimizing the neck region's geometric parameters (length, wall thickness, curvature radius) to resist stress concentration during alkaline cleaning. These parameter modifications enable the container to withstand multiple cleaning cycles with alkaline solutions, thereby supporting repeated refilling and extending the container's service life
Solution Approach 2:
The patent applies preliminary anti-action by pre-reinforcing the neck region with increased wall thickness and optimized geometry before the container undergoes cleaning cycles. This preventive reinforcement counteracts the stress-induced microcrack formation that would otherwise occur during subsequent alkaline cleaning, allowing the container to maintain integrity over multiple refilling cycles
Data Source
AI summary
The invention relates to a refillable plastic container (100) which comprises a neck (10) having a neck opening (11) and a container body enclosing a filling volume which are separated from one another by a substantially radially protruding support ring (30). The neck of the plastic container has an axial length (L) equal to or less than 17.25 mm, measured from a mouth rim (12) of the neck opening to an underside of the support ring.