Blow Molding Preform Inner Coating Thermal Management
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Solution Overview
Problem
The existing blow molding and filling processes for plastic containers, particularly those made from PET, suffer from significant heat energy losses due to the thermal conductivity of the mold and fluid used, leading to inconsistencies in container formation and filling, as the neck finish of the preform does not contribute to heat distribution during the blow molding process.
Innovation Solution
A preform with a coating on its inner surface having a thermal conductivity lower than the material forming the preform is used, which reduces heat energy loss during the blow molding process by maintaining the preform's temperature above the phase change/solidification temperature, either by remaining intact or dissolving/evaporating into the liquid, ensuring consistent container formation and filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a preform is heated prior to blow molding to maintain temperature above phase change/solidification temperature, then the preform can be formed into containers with desired aesthetic and functional properties, but significant heat energy is lost to the mold and fluid used for expansion
Solution Approach 1:
A coating layer is applied to the inner surface of the preform as an intermediary substance between the preform material and the external environment (mold and fluid). This coating layer has lower thermal conductivity than the preform material, acting as a thermal barrier that reduces heat transfer from the preform to the mold and fluid, thereby maintaining preform temperature while reducing heat energy loss.
2Manufacturing precision
If the preform temperature is maintained during blow molding, then consistent container formation is achieved, but the neck finish heat energy remains unavailable for distribution during the blow molding process
Solution Approach 1:
The coating layer serves as a thermal barrier that prevents heat loss from the preform body while allowing the neck finish to retain its heat energy. This intermediary layer ensures that the neck finish heat energy remains available for distribution during the blow molding process, improving both container formation consistency and heat energy utilization.
3Ease of manufacture
If blow molding and filling are performed as separate independent processes, then each process can be optimized independently, but significant costs are incurred and thermal properties are not maintained during transition
Solution Approach 1:
The coating layer on the preform inner surface acts as a thermal barrier that maintains heat energy during the transition from blow molding to filling operations. This allows the preform to retain its thermal properties throughout the process transition, enabling cost-effective integrated systems while maintaining the ability to optimize each process independently.
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 coating effectively maintains the thermal properties of the preform during expansion and filling, reducing heat losses and ensuring the preform remains at or above the phase change/solidification temperature, resulting in improved consistency and quality of the formed containers.
Implementation Method 1
the coating having a thermal conductivity less than a thermal conductivity of a material forming the preform; the coating reduces heat energy loss from the heated preform during the delivering step
Data Source
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AI summary
A method and a preform (10,110,210,24) for blow molding to form a plastic container are disclosed, the preform (10,110,210,24) having a coating (126,226,26) formed on an inner surface (28) thereof. The coating (126,226,26) reduces a loss of heat energy from the heated preform (10) during expansion thereof to ensure the preform (10,110,210,24) maintains a temperature at or above the phase change/solidification temperature of the material forming the preform (10,110,210,24).