Odor-Active Zeolite in PCR Resin for Limonene Reduction
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Solution Overview
Problem
Post-consumer recycled (PCR) materials often exhibit undesirable organoleptic properties such as taste and odor due to volatile organic compounds like limonene, which pose challenges for their use in consumer products like food and beverage containers, as existing processes are inadequate in reducing these contaminants.
Innovation Solution
A composition comprising at least 50% weight polyolefin PCR resin with an initial limonene level of at least 5 ppm, combined with a virgin ethylene-based polymer and an odor-active zeolite having a beta, FAU, or MFI crystal structure, and a Si/Al molar ratio from 1 to 100, followed by devolatilization steps to reduce limonene levels below 3 ppm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If typical fabrication processes are used for PCR resin-containing consumer products, then production efficiency is maintained, but volatile organic compounds such as limonene are not sufficiently reduced
Solution Approach 1:
The patent applies preliminary devolatilization to the PCR resin before it is combined with other materials in the fabrication process. This pre-treatment removes volatile organic compounds like limonene from the recycled resin, ensuring that subsequent manufacturing steps can proceed efficiently without being hindered by odor-active contaminants. The devolatilization step is performed in advance, allowing standard fabrication processes to maintain their productivity while producing cleaner final products.
2Loss of substance
If PCR materials are re-processed and re-incorporated into consumer articles, then resource consumption is reduced, but undesirable taste and odor properties are introduced
Solution Approach 1:
The patent extracts and removes volatile organic compounds, particularly limonene and oxygenated compounds, from the post-consumer recycled resin through devolatilization processes. By taking out these harmful substances before the resin is re-incorporated into new consumer articles, the material retains its environmental benefits while losing the undesirable taste and odor properties that would otherwise contaminate the new products.
Solution Approach 2:
The patent introduces devolatilization as an intermediary treatment step between the collection of post-consumer materials and their re-processing into new products. This intermediate process acts as a mediator that cleanses the recycled resin of volatile contaminants, allowing the material to transition from a contaminated state to a clean state suitable for food and beverage container applications.
3Object-affected harmful factors
If devolatilization steps are performed to reduce limonene levels, then organoleptic properties are improved, but process complexity increases
Solution Approach 1:
By performing devolatilization as a preliminary step before main fabrication processes, the patent addresses organoleptic properties early in the workflow. This approach consolidates the complexity into a single upfront treatment rather than requiring multiple intervention points throughout manufacturing, making the overall process more manageable despite the added step.
Solution Approach 2:
The devolatilization process allows the PCR resin to self-cleanse of volatile contaminants through controlled heating and vacuum application. The resin essentially serves itself by undergoing thermal treatment that drives off unwanted volatiles without requiring complex chemical treatments or multiple processing stages, thereby improving organoleptic properties with relatively simple equipment.
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 solution effectively reduces the limonene level and improves the organoleptic properties of PCR resin-containing compositions, making them suitable for use in consumer products by significantly decreasing volatile organic compounds, thereby enhancing their usability in food and beverage containers.
Implementation Method 1
at least one odor-active zeolite, wherein the odor-active zeolite has a beta, FAU, and/or MFI crystal structure and a Si/Al molar ratio from 1 to 100
Implementation Method 2
producing the PCR resin-containing composition having reduced taste and/or odor as well as a reduced limonene below 3 ppm by performing one or both of the following devolatilization steps
Data Source
AI summary
The present disclosure provides embodiments of a composition comprising post-consumer recycled resin comprising: at least 50 weight percent polyolefin, having an initial limonene level of at least 5 ppm; virgin ethylene-based polymer; and at least one odor-active zeolite, wherein the odor-active zeolite has an FAU crystal structure, an MFI crystal structure, and/or a beta crystal structure and a Si/Al molar ratio from 1 to 100, wherein the composition has a reduced limonene level of less than 3 ppm. The present disclosure also provides embodiments of a method of reducing taste and/or odor in a post-consumer recycled (PCR) resin-containing composition.