Preform Surface Roughness for Low-Pressure Container Release
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Solution Overview
Problem
Existing blow-molded containers, especially those with volumes over three litres, face challenges in controlled release of inner layers from outer layers at low pressures, often requiring high pressures due to adherence issues, and lack effective solutions for gas migration and oxygen scavenging.
Innovation Solution
A preform assembly with an outer and inner preform, where at least one preform has a surface roughness of 0.1 Ra or higher, and the use of metal or metalized particles to enhance surface roughness, allowing for reduced pressure release and integration of scavengers to prevent gas migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth surfaces are used for preforms, then ease of manufacture is improved, but high pressure is required to release inner layers from outer layers
Solution Approach 1:
The patent applies local quality by creating a rough surface layer specifically at the interface between inner and outer preforms, while keeping other surfaces smooth. This localized roughness (achieved through metal or metalized particles) provides mechanical interlocking that reduces release pressure, without affecting the overall ease of manufacture of the preforms.
2Stress or pressure
If rough surfaces are used to reduce release pressure, then pressure requirement is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the surface roughness parameter at the preform interface by incorporating metal or metalized particles during injection molding. This parameter change creates the desired rough texture that reduces release pressure, while the process itself remains integrated into the existing injection molding operation, avoiding additional manufacturing steps or equipment complexity.
3Ease of manufacture
If mono material preforms are used, then manufacturing simplicity is improved, but gas migration and oxygen scavenging capabilities are reduced
Solution Approach 1:
The patent uses composite materials by incorporating metal or metalized particles into the plastic preform matrix. These particles provide oxygen scavenging and gas migration prevention capabilities, enhancing reliability. The composite structure is achieved through standard injection molding processes, maintaining manufacturing simplicity while adding functional benefits.
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 enhanced surface roughness reduces the necessary pressure for releasing inner from outer layers, and the scavengers limit gas migration, improving container integrity and safety while maintaining content quality.
Implementation Method 1
at least one of the inner and outer preform has a surface region in contact with the other of the inner and outer preform, wherein at least part of said region has a surface roughness of at least 0.1 Ra and/or a surface roughness which is at least 0.1 Ra higher than the surface roughness of the surface area of the other of the inner and outer preform with which it is in contact
Implementation Method 2
the scavengers limit gas migration, improving container integrity and safety while maintaining content quality
Data Source
AI summary
Container comprising an inner container and an outer container with facing surfaces, wherein at least part of at least one of the facing surfaces has a surface roughness higher than about 0.1 Ra and/or wherein the difference in roughness of the facing surfaces is at least over a part more than about 0.1 Ra.