Plastic Granulate Sterilization via Radiation and Plasma
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Solution Overview
Problem
Existing methods for producing plastic containers, particularly through the BFS process, fail to adequately reduce microbiological contaminants on the surface of plastic granulate, leading to high microbiological impact due to factors like incorrect handling and storage, and previous sterilization methods are either ineffective or leave toxic residues.
Innovation Solution
The method involves treating the plastic granulate with high-energy radiation, plasma treatment, or chemical sterilization gases to significantly reduce microbiological contaminants on the granulate surface, allowing for effective sterilization without the need for subsequent container sterilization, enabling the use of radiation-sensitive polymers like polypropylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature sterilization (above 200°C) is applied to sterilize container interiors, then sterilization effectiveness is improved, but the choice of plastic materials is limited due to low melting temperatures of polymers like polyethylene and polypropylene
Solution Approach 1:
The patent applies preliminary sterilization to the plastic granulate before extrusion and container formation. By treating the granulate with ionizing radiation or plasma before it is processed into containers, the sterilization is performed at low temperatures that do not affect the polymer material, thus maintaining both sterilization effectiveness and material versatility
Solution Approach 2:
The patent replaces the thermal sterilization mechanism (heating) with alternative mechanisms such as ionizing radiation (electron beam, gamma radiation) or plasma treatment. These non-thermal sterilization methods achieve effective germ reduction without subjecting the plastic material to high temperatures that would cause melting or degradation
2Reliability
If chemical sterilization agents (e.g., hydrogen peroxide vapor) are applied to sterilize containers, then sterilization effectiveness is improved, but toxic residues contaminate the filling material with harmful consequences
Solution Approach 1:
The patent replaces chemical sterilization mechanisms with physical mechanisms such as ionizing radiation (electron beam, gamma radiation) and plasma treatment. These physical methods achieve sterilization through direct energy interaction with microorganisms, breaking their cellular structures without leaving any chemical residues that could contaminate the filling material
Solution Approach 2:
The patent employs sterilization methods that leave no persistent residues. The energy from radiation or plasma acts temporarily to sterilize the granulate, and once the process is complete, no harmful substances remain in the plastic material or subsequent container product
3Reliability
If conventional sterilization methods are applied during BFS production, then sterilization is achieved, but the long treatment times (several hours) are incompatible with modern production cycle times (2-4 seconds)
Solution Approach 1:
The patent replaces slow thermal diffusion-based sterilization with rapid energy deposition methods such as electron beam radiation or plasma treatment. These methods deliver sterilization energy directly and instantly to the granulate surface, achieving effective germ reduction in seconds rather than hours, thus compatible with high-speed BFS production
Solution Approach 2:
The patent enables continuous sterilization of granulate as it flows through the extruder feed system. The radiation or plasma treatment is applied continuously during the feeding process, maintaining uninterrupted production flow without requiring separate sterilization cycles or stopping the production line
4Productivity
If plastic granulate is not sterilized before extrusion, then production speed is maintained, but microbiological contaminants on granulate surface lead to high microbiological impact in final products
Solution Approach 1:
The patent performs preliminary sterilization of the plastic granulate at the beginning of the production process, before extrusion and container formation. This upfront treatment ensures that the granulate is free from microbiological contaminants when it enters the extruder, maintaining both high production speed and excellent microbiological quality in the final products
Solution Approach 2:
The patent uses rapid non-thermal sterilization methods (electron beam, gamma radiation, plasma) that can treat granulate in seconds, allowing sterilization to be integrated into the high-speed production flow without creating bottlenecks or slowing down the overall manufacturing process
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
This approach achieves a substantial reduction in microbiological contaminants, with high-energy radiation methods showing a 1000-fold improvement in germ count reduction, while avoiding chain degradation and toxic residues, and allowing for rapid production cycles.
Implementation Method 1
treating the plastic granulate with high-energy radiation
Implementation Method 2
plasma treatment
Data Source
AI summary
A method reduces the microbiological loading of container products made at least partially of at least one plastic material. As part of a first production process, a plastic granulate (29) is fed to an extruder device (19), which melts the granulate (29). As part of a subsequent production process, the melted granulate is forwarded onto a blow-molding, filling and sealing machine for obtaining the respective container product. At least in parts of the first production process, the plastic material undergoes at least one of the following treatment steps: high-energy radiation and/or plasma treatment and/or a gas having a sterilizing effect.