Lightweight Hot-Fill Container Finish Biaxial Orientation
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Solution Overview
Problem
Hot-fill plastic containers face issues with neck distortion due to the amorphous state of the neck portion, which softens at temperatures below the filling temperatures, requiring increased thickness and intensive cooling to prevent failure, and are sensitive to process variations.
Innovation Solution
A lightweight neck finish with an annular lower flange, annular upper flange, and threads above the upper flange, optimized for reduced material usage while maintaining dimensional stability, featuring a reduced height and wall thickness to withstand hot-fill temperatures without distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the neck portion thickness is increased to prevent softening at hot-fill temperatures, then dimensional stability is improved, but material usage increases and manufacturing cost increases
Solution Approach 1:
The patent applies local quality by creating a biaxially oriented neck finish with different structural properties than the container body. The neck portion is specifically oriented to achieve dimensional stability at hot-fill temperatures without requiring increased thickness throughout the entire container, thus reducing overall material usage while maintaining local stability where needed.
Solution Approach 2:
The patent changes the physical parameters of the neck finish by applying biaxial orientation through stretching in both machine and transverse directions. This transforms the amorphous neck material into a semi-crystalline structure with enhanced thermal stability, allowing the neck to withstand hot-fill temperatures without requiring increased thickness.
2Stability of the object's composition
If the neck portion thickness is increased to prevent distortion, then dimensional stability is improved, but manufacturing complexity increases due to intensive cooling requirements
Solution Approach 1:
The patent applies preliminary action by pre-orienting the neck finish material biaxially during the blow molding process before the hot-fill operation. This pre-orientation creates a semi-crystalline structure that inherently resists thermal distortion, eliminating the need for post-filling intensive water cooling systems and reducing manufacturing complexity.
3Stability of the object's composition
If the preform neck area is heated during blow molding, then molecular transformation to semi-crystalline structure is achieved, but energy consumption increases and process complexity increases
Solution Approach 1:
The patent applies local quality by selectively heating only the preform body portion during blow molding while leaving the neck area unheated. The neck is then oriented through mechanical stretching to achieve semi-crystalline structure without requiring thermal energy, thus reducing overall energy consumption while maintaining the desired molecular transformation where needed.
Solution Approach 2:
The patent replaces thermal processing with mechanical processing for the neck area. Instead of heating the neck to transform its molecular structure, the patent uses biaxial mechanical stretching to achieve semi-crystalline orientation, substituting mechanical energy for thermal energy and reducing heating requirements.
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 lightweight finish provides adequate stability and cost savings by using less material while preventing neck distortion and thread failure during the hot-fill process, allowing for efficient manufacturing of hot-fill containers.
Implementation Method 1
the preform body is heated to a suitable temperature
Implementation Method 2
High pressure air is then introduced into the preform and forces the plastic material of the preform into contact with the blow mold
Implementation Method 3
The plastic cools sufficiently such that when the blow mold opens, the newly formed structure retains its shape
Implementation Method 4
The body of the container, having been biaxially oriented through the axial stretching followed by radial stretching undergoes a molecular change which transforms the structure of the preform into a semi-crystalline container wall
Implementation Method 5
intensive water cooling of the exterior of the container neck is necessary immediately after capping in order to minimize the thread distortion
Data Source
AI summary
A lightweight finish for a hot-fill container uses less material compared to existing hot-fill container finishes. The lightweight finish yields a cost savings while still providing adequate dimensional stability to allow the container to maintain its shape during the hot-fill process.