Recyclable Pigments for PET Beverage Containers
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Solution Overview
Problem
Current PET containers with coloring pigments and dyes are not recycle-friendly, leading to separate collection and lower resale value, and existing decontamination methods are complex and costly.
Innovation Solution
Incorporating recycle-friendly pigments with a melting temperature 20-50°C higher than the base polymer into PET preforms, which remain intact during injection molding and melt into the polymer during recycling, ensuring compatibility and minimal impact on polymer properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional pigments and dyes are used in PET containers, then visual characteristics and color effects are improved, but recyclability deteriorates requiring separate collection streams
Solution Approach 1:
The patent changes the key parameter of pigment melting temperature to be higher than the base polymer melting point. This parameter change allows the pigment to remain stable during container processing temperatures while eventually integrating during recycling, thus improving both visual characteristics and recyclability simultaneously
Solution Approach 2:
The pigment is selected with predetermined properties (melting temperature 20-50°C higher than base polymer) before processing. This preliminary selection ensures the pigment will automatically integrate during recycling without requiring additional separation or treatment steps, resolving the recyclability issue while maintaining visual effects
2Adaptability or versatility
If existing decontamination methods are used to remove pigments, then recyclability is improved, but process complexity and cost increase significantly
Solution Approach 1:
Instead of treating the pigment as a contaminant to be removed, the invention converts it into a beneficial component that naturally integrates during recycling. The pigment's higher melting point, which initially seemed to hinder recycling, actually facilitates automatic integration during the remelting process, eliminating the need for complex decontamination equipment
Solution Approach 2:
The recycling process itself performs the integration function. When recycled PET is remelted, the pigment automatically melts and incorporates into the base polymer without requiring external intervention, specialized equipment, or additional processing steps. The system serves itself by using the recycling heat to complete the integration
3Illumination intensity
If pigment particle size is reduced for better dispersion, then visual effects are improved, but processing difficulty increases
Solution Approach 1:
The patent specifies an optimal particle size range (1-140 μm) that balances dispersion quality and processing ease. This parameter optimization ensures sufficient surface area for good visual effects while maintaining particles large enough to handle easily during mixing and processing operations
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
Enables PET containers to be processed in existing recycling streams with minimal additional steps, maintaining polymer properties and achieving desired visual effects while ensuring pigment compatibility and recyclability.
Implementation Method 1
When the container is remelted during subsequent processing, such as post-consumer recycling, the pigment melts and transesterifies into the base polymer
Implementation Method 2
the pigment melts and transesterifies into the base polymer
Data Source
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AI summary
A thermoplastic article includes one or more recyclable-friendly synthetic coloring pigments. The pigment has a melting temperature that is about 20 to about 50?C higher than that of the base polymer. This enables the pigment to remain predominately intact (e.g., unmelted) during injection molding and act as a colorant in the preform and resulting blow molded container. When the container is remelted during subsequent processing, such as post-consumer recycling, the pigment melts and transesterifies into the base polymer. Thus, upon such further processing, the pigment effectively is subsumed into the base polymer and does not affect the basic characteristics and properties of the base polymer.