Recycled Polymer Pellet Devolatilization for Food-Contact Molding
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Solution Overview
Problem
Current recycling techniques are unable to effectively utilize post-consumer recycled articles, particularly in creating new products or materials, due to specific material requirements that are not met by existing processes.
Innovation Solution
A method for producing post-consumer recycled high density polyethylene and polypropylene pellets suitable for food contact articles, involving grinding, sorting by melt index, forming into pellets, and devolatilizing to achieve the required melt flow characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If post-consumer recycled plastics are used directly in molding processes, then material availability is improved, but material quality (melt index) deteriorates due to degradation from previous use and contamination
Solution Approach 1:
The patent applies parameter changes by adjusting the melt index of recycled plastics through controlled degradation processes. The system transforms the material parameters (melt index, molecular weight distribution) to match specific molding process requirements, converting low-quality post-consumer material into usable feedstock for different application tiers.
Solution Approach 2:
The patent segments the recycled plastic material into different quality tiers based on melt index ranges. By categorizing material into high, medium, and low melt index groups, the system can allocate appropriate material to suitable applications, maximizing utilization of available recycled content while maintaining product quality standards.
2Reliability
If post-consumer recycled materials are processed through multiple sorting and processing steps, then material quality is improved, but process complexity increases
Solution Approach 1:
The patent uses melt index as a key parameter for automated sorting decisions. By measuring and categorizing material based on this single critical parameter, the system achieves effective quality control without requiring complex multi-parameter analysis, simplifying the overall processing architecture.
Solution Approach 2:
The patent replaces manual or complex mechanical sorting systems with automated optical or near-infrared detection combined with robotic sorting mechanisms. This substitution enables rapid, non-contact material characterization and sorting based on polymer type and quality parameters, reducing system complexity while improving sorting accuracy.
3Adaptability or versatility
If post-consumer recycled materials are sorted and processed into different quality tiers, then adaptability to different molding processes is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary sorting and quality assessment of post-consumer materials before they enter the main processing stream. By pre-categorizing material into melt index tiers and polymer types early in the process, the system eliminates the need for repeated sorting operations downstream, reducing overall processing time while maintaining adaptability to different molding requirements.
Solution Approach 2:
The patent rapidly determines key material parameters (melt index, polymer type) using quick measurement techniques such as near-infrared spectroscopy or optical sorting. This rapid parameter assessment enables fast sorting decisions without significant time penalties, allowing the system to adapt material to different molding processes efficiently.
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 process enables the production of fit-for-food contact articles from 100% post-consumer recycled content, eliminating the need for additives and ensuring the materials meet the necessary melt index requirements for molding processes.
Implementation Method 1
devolatilizing the plurality of post-consumer high-density polyethylene and polypropylene pellets in a devolatilization chamber
Data Source
AI summary
A method of producing fit-for-food contact devolatilized post-consumer thermoplastic polymer pellets derived from higher melt index post-consumer recycled thermoplastic polymer, in various aspects, comprises: providing higher melt index post-consumer recycled thermoplastic polymer having; forming the higher melt index post-consumer recycled thermoplastic polymer into a plurality of higher melt index polymer pellets; after forming the higher melt index post-consumer recycled thermoplastic polymer into the plurality of higher melt index post-consumer polymer pellets, devolatilizing the plurality of higher melt index post-consumer polymer pellets in a devolatilization chamber to produce a plurality of devolatilized higher melt index post-consumer polymer pellets; and providing the plurality of devolatilized post-consumer high-density polyethylene and polypropylene pellets for use in at least one of an injection molding, compression molding, or flexible packaging processes to produce a plurality of fit-for-food contact articles from the plurality of devolatilized post-consumer high-density polyethylene and polypropylene pellets.