Plastic Identification via Fluorescence Decay Time
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Solution Overview
Problem
Current methods for recycling plastics, particularly chemically similar plastics and those with additives like silicones and flame retardants, lack precision and are complex, making it difficult to identify and distinguish between different types of plastics and their contaminants.
Innovation Solution
A method utilizing the fluorescence decay time of intrinsic fluorescence to identify plastics and their additives, employing multi-exponential fluorescence decay time constants and phase-sensitive detectors to differentiate between various plastic types and contaminants, including chemically similar plastics and those with additives like flame retardants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical methods are used for plastic identification, then detection can be performed, but measurement precision is insufficient especially for chemically similar plastics
Solution Approach 1:
The invention extracts and measures the intrinsic fluorescence decay time property of the plastic material itself, rather than detecting external markers or relying on conventional optical properties. By focusing on the characteristic fluorescence decay time of the polymer chains, the method achieves precise identification of chemically similar plastics without requiring additional marker systems.
Solution Approach 2:
The invention changes the measurement parameter from conventional optical properties (absorption, reflection) to fluorescence decay time. This parameter change enables differentiation of chemically similar plastics that appear identical under conventional optical methods, as different polymers exhibit distinct fluorescence decay time characteristics.
2Reliability
If conventional recycling methods are used, then processing can continue, but contamination from additives like flame retardants and oils cannot be reliably detected
Solution Approach 1:
The fluorescence decay time measurement method serves multiple functions simultaneously: it identifies the plastic type, detects the presence of additives like flame retardants, and identifies contamination from oils and other substances. This multi-functionality is achieved by analyzing characteristic changes in fluorescence decay patterns caused by different materials and contaminants.
Solution Approach 2:
The invention replaces complex mechanical sorting and chemical analysis systems with an optical fluorescence measurement system. By substituting physical/chemical methods with optical detection, the system achieves reliable contaminant detection while reducing processing time and complexity.
3Productivity
If plastics are sorted by chemical similarity, then recycling can proceed, but the process becomes complex and difficult
Solution Approach 1:
The plastic materials themselves provide the identification information through their intrinsic fluorescence decay time properties. Each plastic type and contaminant combination exhibits characteristic fluorescence decay patterns that serve as natural identifiers, eliminating the need for complex external sorting mechanisms or database matching systems.
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 enables reliable, efficient, and precise identification of plastics and their additives, allowing for effective sorting and recycling, even for plastics contaminated with oils or other substances, and facilitates the detection of additives like platinum catalysts and flame retardants.
Implementation Method 1
A method for identifying plastic and/or one or more additives contained in the plastic, in particular by determining the fluorescence decay time of the intrinsic fluorescence of the plastic and/or the one or more additives contained in the plastic
Data Source
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AI summary
The invention relates to a method for identifying plastics and/or the additives therein, wherein at least some of the plastic material is irradiated with light of at least one wavelength, at least some of the light reflected by the plastic material is detected and analyzed, and the plastic material and/or the additive therein is/are identified on the basis of the result of the analysis. The disclosed method is characterized in that a fluorescence decay time constant of the intrinsic fluorescence of the plastic material and, if applicable, of the additive(s) therein is determined on the basis of the detected light, and the plastic material and/or the additive(s) therein is/are identified on the basis of the determined fluorescence decay time constant.