JP5539421B2 - Plastic identification device and method - Google Patents

Description

  The present invention relates to an apparatus for identifying a reusable plastic obtained when household electrical appliances are discarded / collected and crushed.

  Some of the plastic used in discarded home appliances is dismantled and reused, but the plastic used for small parts that cannot be dismantled or parts that have complex structures is finely ground together with other materials such as metal. Is done. Metal pieces and plastic pieces are mixed in the crushed pieces, and various polymers such as polypropylene (hereinafter referred to as PP), polystyrene (hereinafter referred to as PS), acrylonitrile-butadiene-styrene (hereinafter referred to as ABS) are mixed in the plastic pieces. There are a mixture of plastics mainly composed of

  In order to reuse a crushed plastic piece whose material is unknown, it is necessary to identify the material of the plastic piece and separate and collect it for each material. Since the size of the crushed pieces is often as small as several millimeters, in order to identify the material of a certain amount of plastic pieces, it is necessary to evaluate and identify many plastic pieces. Therefore, an identification device that can be evaluated in a short time is desirable. Metal pieces can be sorted using specific gravity, electricity or magnetism, but these methods cannot be applied to plastic pieces.

  As one method for identifying the material of a plastic piece, for example, Patent Document 1 below proposes a method using a Raman scattering spectrum. A single color laser light emitted from a laser light source is irradiated onto a plastic material, and the light scattered from the plastic material is collected, and the collected light is subjected to spectroscopic analysis. The band pattern and database of the measured Raman scattering spectrum are used. It is described that the type of plastic material is identified by collating with a stored known band pattern.

  In addition, the Raman scattering intensity at one or more peak positions (hereinafter known peak positions) and the Raman scattering intensity at the baseline position (hereinafter known baseline positions) set in advance by measuring the Raman scattering spectrum of a known plastic is stored. One or more known points obtained in the step of storing in the means and the step of irradiating the identification target plastic as the identification target with laser light and acquiring the Raman scattering signal from the Raman scattered light scattered from the identification plastic The material of the plastic based on the Raman scattering intensity at the Raman shift wave number corresponding to the peak position, the Raman scattering intensity at the Raman shift wave number corresponding to the known baseline position, and the Raman scattering intensity of one or more known plastics stored in advance. Is described in Patent Document 2 below, for example. ing.

JP 2000-356595 A Japanese Patent No. 4203916

  Conventionally, plastics recovered from discarded home appliances include various additives, and one of them is a carbon filler such as carbon black. The appearance of the plastic containing the carbon filler is black. If classified from the viewpoint of light transmittance, there are plastics with various brightness from transparent color and white color that transmit light to black color that hardly transmits light. In order to reuse a plastic piece, it is necessary to identify the material, separate it and collect it regardless of its brightness. In order to irradiate a plastic with laser light and obtain a strong Raman scattering signal in a short time, it is necessary to increase the laser output.

  In transparent and white plastics that transmit light, the melting of plastics with laser light is not a problem, but when measuring the Raman scattering spectrum of black plastics containing carbon fillers such as carbon black, the output is When high laser light is irradiated, there is a problem that the plastic is melted due to heat generation by light absorption of the carbon filler and a Raman scattering spectrum cannot be obtained.

  Therefore, in order to obtain a Raman scattering spectrum of black plastic, it is necessary to irradiate and measure laser light having a low output. However, when the laser output is low, since the Raman scattering signal is weak, the S / N ratio becomes small, and it is necessary to lengthen the integration time of the signal, and there is a problem that it takes time for identification.

  Patent Document 1 discloses an identification device that measures black plastic by setting the wavelength of laser light to be irradiated to 640 nm to 950 nm and the numerical aperture NA of the fiber head objective lens in a range of 0.6 <NA ≦ 1. Although it is described, in order to obtain a Raman scattering signal in a short time, when the laser output is increased, the black plastic is melted and the Raman scattering spectrum cannot be measured. In addition, since it is not an optimum condition for obtaining a Raman scattering signal of a transparent color or white plastic, it takes time for identification.

  Further, the identification device described in Patent Document 2 can measure a Raman scattering spectrum in several milliseconds, but since a laser output of 100 mW or more is necessary, when black plastic is measured, the black plastic is melted. Thus, it is impossible to measure the Raman scattering spectrum.

  The present invention has been made to solve the above-described problems. From a transparent color or white plastic that transmits light to a black plastic that hardly transmits light, the SN ratio is improved without melting the plastic. An object of the present invention is to provide a plastic identification apparatus and method capable of measuring a large Raman scattering spectrum.

  The present invention relates to a first laser beam having a first wavelength, a laser light source unit that generates a second laser beam having a second wavelength shorter than the first wavelength, and the first and second laser beams. A multi-channel spectroscopic unit that detects Raman scattered light generated by irradiating a plastic piece with a laser beam to identify the material and obtains a Raman scattered spectrum, and compares the detected Raman scattered spectrum with the standard Raman spectrum. A data processing device for identifying a plastic material, wherein the data processing device has an intensity of a peak position of one or more predetermined points of the Raman scattering spectrum by the first laser light being less than a predetermined intensity. In the plastic identifying device or the like, the laser light source unit is irradiated with the second laser light to identify the material.

  The present invention provides a plastic identification device capable of measuring a Raman scattering spectrum having a large S / N ratio without melting the plastic, from a transparent color or white plastic that transmits light to a black plastic that hardly transmits light. it can.

It is a figure which shows the structure of the identification device of the plastics concerning Embodiment 1, 2 of this invention. It is a flowchart which shows the identification process using the plastic identification device which concerns on Embodiment 1 of this invention. It is a figure which shows the result of having measured the Raman scattering spectrum of the white plastic and black plastic which concern on Embodiment 1 of this invention. It is a figure which shows the result of having measured the Raman scattering spectrum of the black plastic which concerns on Embodiment 1 of this invention. It is a figure which shows the result of having measured the Raman scattering spectrum of the white plastic which concerns on Embodiment 1 of this invention. It is a flowchart which shows the identification process using the identification device of the plastics concerning Embodiment 2 of this invention. It is a figure which shows the structure of the identification device of the plastics concerning Embodiment 3 of this invention. It is a figure which shows the structure of the identification device of the plastics concerning Embodiment 4 of this invention.

  The plastic identifying apparatus and method according to the present invention will be described below with reference to the drawings in accordance with each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. In addition, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

Embodiment 1 FIG.
FIG. 1 shows the configuration of a plastic identification device according to Embodiment 1 of the present invention. In FIG. 1, the plastic identification device 1 includes a first laser light source 2 and a second laser light source 3, a first laser light 9 emitted from the first laser light source 2, and a first laser light emitted from the second laser light source 3. Mirror 6 and lens 5 for guiding the second laser beam 10 to the plastic piece 4, the first Raman scattered light 11 generated by the first laser light source 2, and the second Raman scattering generated by the second laser light source 3. A multichannel spectroscopic unit 7 for spectrally detecting and detecting the light 12 and a data processing device 8 for identifying the material of the plastic by comparing the obtained Raman scattering spectrum with a previously obtained Raman spectrum of plastic. Consists of.

  The data processing device 8 is connected to the first laser light source 2 and the second laser light source 3 as well as the multi-channel spectroscope 7 together with the data processing (not shown because the figure is difficult to see), This is a control processing unit that also controls the operation of the entire plastic identification device that also performs control of changing spectral conditions in the multichannel spectrometer 7 when the wavelength of the laser light source is changed. For example, a storage unit (memory: not shown) is provided. Consists of including computers. In the storage unit, standard data for identification including standard Maran scattering spectra for each plastic and peak positions to be sampled are stored in advance or measured and stored in advance.

  Next, the operation of the plastic identifying apparatus according to Embodiment 1 of the present invention will be described. FIG. 2 is a flowchart showing an identification process using the plastic identification device according to Embodiment 1 of the present invention. Hereinafter, description will be made with reference to FIGS. 1 and 2.

  By irradiating the first laser light 9 from the first laser light source 2, the plastic piece 4 is irradiated through the mirror 6 and the lens 5. The Raman scattered light 11 is scattered (step S1). The Raman scattered light 11 is collected via the lens 5 and detected by the multichannel spectroscope 7 to obtain a Raman scattered spectrum (step S2). The acquired Raman scattering spectrum data is sent to the data processing device 8, and the intensity of one or more preset peak positions (predetermined one or more peak positions) is a predetermined intensity (predetermined intensity). ) It is determined whether or not (step S3).

  When the intensity of the peak position at one or more predetermined points is not higher than the predetermined intensity (less than the predetermined intensity), the laser light source is switched, and the spectral condition in the multichannel spectrometer 7 is changed to change the second laser light source. The second laser light 10 from 3 is irradiated onto the plastic piece 4 via the mirror 6 and the lens 5, whereby the second Raman scattered light 12 generated by the irradiation of the laser light 10 is scattered (step). S4). The Raman scattered light 12 is collected via the lens 5 and detected by the multichannel spectrometer 7 to obtain a Raman scattered spectrum (step S5). The acquired Raman scattering spectrum data is compared with a known standard Raman spectrum (identification standard data) of plastic obtained and stored in the data processing device 8 to identify the plastic material (step S6).

  In step S3, the acquired Raman scattering is obtained when the intensity of one or more predetermined peak positions in the Raman scattered light 11 generated by the laser light 9 emitted from the first laser light source 2 is equal to or higher than the predetermined intensity. The spectral data is identified in the data processing device 8 by collating with known standard data for identifying plastics obtained in advance.

  FIG. 3 shows the result of measuring the Raman scattering spectra of white plastic and black plastic using the first laser light source 2 in the plastic identifying apparatus according to Embodiment 1 of the present invention (intensity-wave number characteristics, the same applies hereinafter). FIG. The plastic material is ABS, and the wavelength of the laser beam is 633 nm. The laser light irradiation conditions of the first laser light source 2 are adjusted to conditions suitable for obtaining white plastic Raman scattered light. W represents a measured Raman scattering spectrum of white plastic and B represents black plastic.

In the white plastic (W), CN stretching peak near the wave number 2250 cm ^-1, is CC stretching peak around 1600 cm ^-1 is observed a characteristic Raman scattering peak at ABS. On the other hand, since the Raman scattering intensity of black plastic (B) is small, the peak at around 2250 cm ^-1 and near 1600 cm ^-1 is not observed, the Raman scattering spectra and the known plastic in the data processing device 8, in the case of time, It can be seen that it is impossible to identify the material even by collating with the standard Raman spectrum of ABS.

  This is because, as described above, the laser light irradiation condition of the first laser light source 2 is a measurement condition suitable for white plastic, so that the Raman scattering signal of black plastic cannot be obtained sufficiently. If the output of the laser beam is increased to increase the Raman scattering signal intensity of the black plastic, melting due to heat generation occurs, making measurement impossible. That is, it is impossible to obtain sufficient Raman scattering signal intensity of black plastic under measurement conditions suitable for white plastic. As a method for solving this problem, a method for shortening the wavelength of laser light has been found as a method for increasing the Raman scattering signal intensity of black plastic.

FIG. 4 is a diagram showing a result of measuring a Raman scattering spectrum of black plastic using the second laser light source 3 in the plastic identifying apparatus according to Embodiment 1 of the present invention. The plastic material is ABS, the wavelength of the laser beam is 514 nm, which is shorter than that of the first laser light source 2, and the laser output is almost the same as that of the first laser light source 2. That is, the laser light irradiation conditions of the second laser light source 3 are adjusted to conditions suitable for obtaining Raman scattering light of black plastic. By shortening the wavelength, it becomes possible to increase the Raman scattering intensity without increasing the laser output. Therefore, in black plastic, a CN stretching peak around 2250 cm ^−1, which is a Raman scattering peak characteristic of ABS, is 1600 cm. A CC stretching peak near ^-1 is observed.

Further, as described above, the second laser light source 3 is a measurement condition suitable for black plastic, contrary to the first laser light source 2, and therefore is suitable for obtaining a Raman scattering signal of white plastic. Absent. FIG. 5 is a diagram showing the result of measuring the Raman scattering spectrum of white plastic using the second laser light source 3, that is, the wavelength of laser light 514 nm, in the plastic identifying apparatus according to Embodiment 1 of the present invention. . A CC stretching peak in the vicinity of 1600 cm ⁻¹ cannot be obtained due to the effect that the background is higher than the Raman scattering spectrum of the white plastic shown in FIG. This is because the fluorescence intensity is increased by irradiation with laser light having a wavelength of 514 nm shorter than the wavelength of 633 nm. That is, since the optimum measurement conditions for obtaining Raman scattered light of white plastic and black plastic are different, it is necessary to evaluate using both the first laser light source 2 and the second laser light source 3.

For example, the first laser light source 2 irradiates the plastic piece 4 with the laser light 9, acquires a Raman scattering spectrum, and sets a predetermined peak position of one or more points and a predetermined intensity to a wave number of 1000 cm ⁻¹ and 700 Count. If it is determined as / sec, as can be seen from the diagram shown in FIG. 3, the white plastic is determined to have a predetermined strength or higher, and the black plastic is determined to be less than the predetermined predetermined strength. Therefore, the black plastic moves to the step of measuring the Raman scattering using the second laser light source 3, and moves to the step of measuring the Raman scattering spectrum shown in FIG. 4 using the second laser light source 3. The

Thereafter, for the white plastic, the Raman scattering spectrum obtained in FIG. 3 and for the black plastic, the Raman scattering spectrum obtained in FIG. Data), in this case, the process proceeds to the step of collating with the standard Raman spectrum of ABS. As described above, in FIG. 3 and FIG. 4, a CN stretching peak near 2250 cm ⁻¹ characteristic of ABS is observed, and a CC stretching peak near 1600 cm ⁻¹ is observed, so that the plastic material can be identified. Become.
Further, as shown in FIGS. 3 and 4, a black plastic having a wavelength shorter than 633 nm is more preferable for obtaining Raman scattering intensity. Therefore, the wavelength of the second laser light source 3 is preferably shorter than 630 nm and longer than 400 nm. Since plastic deteriorates when irradiated with ultraviolet rays, a laser light source having a wavelength of 400 nm or less cannot be used.

Embodiment 2. FIG.
The configuration of the plastic identifying apparatus according to Embodiment 2 of the present invention is the same as that shown in FIG. Next, the operation of the plastic identifying apparatus according to Embodiment 2 of the present invention will be described. FIG. 6 is a flowchart showing an identification process using the plastic identification device according to Embodiment 1 of the present invention. Hereinafter, description will be made with reference to FIGS. 1 and 6.

  The operation until the first Raman scattered light 11 is detected by the multi-channel spectroscope 7 using the first laser light source 2 and the detection result is sent to the data processing device 8 is the same as in the first embodiment ( Steps S1, S2). In the second embodiment, it is determined whether or not the intensity of one or more predetermined predetermined peak positions is less than a predetermined intensity (step S3). When the intensity of the peak position at one or more predetermined points is not less than the predetermined intensity (greater than or equal to the predetermined intensity), the laser light source is switched, and the spectral condition in the multichannel spectrometer 7 is changed to change the second laser light source. 3, the second Raman scattered light 12 is detected by the multi-channel spectroscope 7 and sent to the data processing device 8 (steps 4 and S5). In the data processing device 8, the known standard data for identifying plastics and The material is identified by collation (step SS). If it is less than the predetermined strength in step S3, the material is identified as it is in step S6.

In the second embodiment, contrary to the first embodiment, the laser light irradiation condition of the first laser light source 2 is adjusted to a measurement condition suitable for obtaining Raman scattered light of black plastic. For example, when laser light having a wavelength of 514 nm is used as the first laser light source 2, the Raman scattering spectrum shown in FIG. 5 is obtained for white plastic and FIG. 4 is obtained for black plastic. The first laser light source 2 irradiates the plastic piece 4 with the laser light 9, and a Raman scattering spectrum is acquired, and a predetermined peak position of one or more points and a predetermined intensity are determined as a wave number of 1000 cm ⁻¹ and 700 Count / sec. Then, as can be seen from the diagrams shown in FIGS. 4 and 5, the white plastic is determined to have a predetermined strength or more, and the black plastic is determined to be less than the predetermined strength. Therefore, the white plastic is transferred to the step of performing the Raman scattering measurement using the second laser light source 3.

The laser light irradiation conditions of the second laser light source 3 are adjusted to the measurement conditions suitable for the white plastic, contrary to the first laser light source 2. For example, when laser light having a wavelength of 633 nm is used as the second laser light source 3, the Raman scattering spectrum shown in FIG. 3 can be obtained with white plastic and black plastic. Thereafter, the white plastic represents the Raman scattering spectrum obtained in FIG. 3, the black plastic represents the Raman scattering spectrum obtained in FIG. 4, a known plastic obtained in advance by the data processing device 8, in this case, for ABS identification. The process proceeds to step S6 for collating with standard data. As described above, in FIG. 3 and FIG. 4, a CN stretching peak near 2250 cm ⁻¹ characteristic of ABS is observed, and a CC stretching peak near 1600 cm ⁻¹ is observed, so that the plastic material can be identified. Become.

  Further, as shown in FIGS. 3 and 4, a black plastic having a wavelength shorter than 633 nm is more preferable for obtaining Raman scattering intensity. Therefore, the wavelength of the second laser light source 3 is preferably shorter than 630 nm and longer than 400 nm. Since plastic deteriorates when irradiated with ultraviolet rays, a laser light source having a wavelength of 400 nm or less cannot be used.

  In the second embodiment, the first laser light source 2 is used to measure the black plastic that is a problem of laser light absorption, and the second laser light source 3 is used to measure a transparent color or white plastic that is hardly a problem of laser light absorption. . That is, the black plastic, which is a problem of absorption of laser light, does not need to be measured with the second laser light source 3 after being measured with the first laser light source 2, and therefore the plastic piece measured with the second laser light source 3 is Only the transparent color and white plastic, in which the absorption of the laser beam is hardly a problem. In order to increase the Raman scattering intensity, it is effective to increase the output of the laser beam. Therefore, the irradiation intensity of the second laser beam is preferably larger than the irradiation intensity of the first laser beam.

Embodiment 3 FIG.
FIG. 7 shows the configuration of a plastic identifying apparatus according to Embodiment 3 of the present invention. The measurement part of the Maran scattering spectrum is divided according to the light source. In FIG. 7, the plastic identification device 1 includes a first laser light source 2, a mirror 6 a and a lens 5 a for guiding the laser light 9 emitted from the first laser light source 2 to the plastic piece 4, and the first laser light source 2. A multi-channel spectroscopic unit 7 a for spectrally detecting and detecting the generated Raman scattered light 11, a second laser light source 3, and a mirror 6 b for guiding the laser light 10 emitted from the second laser light source 3 to the plastic piece 4. , A lens 5b, a multi-channel spectroscopic unit 7b for spectrally detecting and detecting Raman scattered light 12 generated by the second laser light source 3, and known standard data for identifying plastics obtained in advance from the obtained Raman scattered spectrum And a data processing device 8 for identifying the material of the plastic by collating.

  The operation of the plastic identifying apparatus according to the third embodiment of the present invention is the same as that described in the first and second embodiments. When the wavelength of the laser light source is changed, it is also necessary to change the spectral conditions of the multichannel spectrometer that detects Raman scattered light. In the third embodiment, by using two multichannel spectrometers 7a and 7b, the trouble of changing the spectral conditions of the multichannel spectrometer can be saved, and the measurement time can be shortened.

  Further, the laser light 9 and the laser light 10 emitted from the first laser light source 2 and the second laser light source 3 may be intermittent operations that are repeated with and without irradiation. However, the laser light 9 and the laser light 10 are plastic. Since the positions irradiated on the pieces 4 are different, the possibility that the Raman scattered light 11 enters the multi-channel spectrometer 7b and the Raman scattered light 12 enter the multi-channel spectrometer 7a is low, and therefore, the irradiation may be performed continuously.

Embodiment 4 FIG.
FIG. 8 shows the configuration of a plastic identifying apparatus according to Embodiment 4 of the present invention. The configuration of the plastic identification device main body 1a is the same as that described in the third embodiment, for example. Under the plastic identification apparatus main body 1a, it is comprised of a transport unit 13 capable of transporting the plastic piece 4. Next, the operation of the plastic identifying apparatus according to Embodiment 4 of the present invention will be described. After the Raman scattering measurement is performed on the plastic piece 4 by the first laser light source 2, the conveyance unit 13 moves the conveyance unit in the direction 14 for conveying the plastic piece, and the second laser light source 3 performs the Raman scattering measurement. The operations of the plastic identification device other than the conveyance of the plastic piece 4 are the same as those described in the third embodiment. The plastic identification device main body 1a may be the one of the first and second embodiments.

  As described above, since the size of the crushed plastic piece is often as small as several millimeters, it is difficult to irradiate the same plastic piece with the laser beam 9 and the laser beam 10 as shown in the third embodiment. In such a case, it is preferable to apply the fourth embodiment.

  Further, the laser light 9 and the laser light 10 emitted from the first laser light source 2 and the second laser light source 3 may be intermittent operations that are repeated with and without irradiation. However, the laser light 9 and the laser light 10 are plastic. Since the positions irradiated on the pieces 4 are different, the possibility that the Raman scattered light 11 enters the multichannel spectrometer 7b and the Raman scattered light 12 enter the multichannel spectrometer 7a is low, and therefore, the irradiation may be performed continuously.

  In each of the above embodiments, the laser light source is the first and second laser light sources 2 and 3, but one laser light source unit (not shown) for irradiating the first and second laser lights is used. You may make it comprise the optical system of each laser beam with a mirror and a lens.

  Further, the data processing device 8 identifies the plastic material and controls the entire plastic identifying device. The data processing device 8 includes a data processing unit for identifying the plastic material, a laser light source unit (2, 3) The multi-channel spectroscope unit (7, 7a, 7b) and the transport unit 13 may be divided into control units that control the material in relation to the identification result, for example.

  Further, the present invention is not limited to the above embodiments, and it is needless to say that all possible combinations of these embodiments are included.

  DESCRIPTION OF SYMBOLS 1 Plastic identification device, 2 1st laser light source, 3 2nd laser light source, 4 Plastic piece, 5 Lens, 5a Lens for 1st laser light source, 5b Lens for 2nd laser light source, 6 Mirror, 6a Mirror for first laser light source, 6b Mirror for second laser light source, 7, 7a, 7b Multichannel spectrometer (multichannel spectrometer), 8 Data processing device, 9 (first) laser light, 10 (Second) laser light, 11 (first) Raman scattered light, 12 (second) Raman scattered light, 13 transport section.

Claims (8)

A laser light source unit that generates a first laser beam having a first wavelength and a second laser beam having a second wavelength shorter than the first wavelength;
A multi-channel spectroscopic unit for detecting Raman scattered light generated by irradiating a plastic piece whose material is identified with the first and second laser lights and acquiring a Raman scattered spectrum;
A data processing device for identifying the material of the plastic by comparing the Raman scattering spectrum of the detected Raman scattered light and the standard Raman spectrum;
With
The data processing device irradiates the laser light source unit with the second laser light when the intensity of one or more predetermined peak positions of the Raman scattering spectrum by the first laser light is less than a predetermined intensity. To identify the material,
A plastic identification device characterized by that. A laser light source unit that generates a first laser beam having a first wavelength and a second laser beam having a second wavelength longer than the first wavelength;
A multi-channel spectroscopic unit for detecting Raman scattered light generated by irradiating a plastic piece whose material is identified with the first and second laser lights and acquiring a Raman scattered spectrum;
A data processing device for identifying the material of the plastic by comparing the Raman scattering spectrum of the detected Raman scattered light and the standard Raman spectrum;
With
The data processing apparatus irradiates the laser light source unit with the second laser light when the intensity of the peak position of one or more predetermined points of the Raman scattering spectrum by the first laser light is higher than a predetermined intensity. To identify the material,
A plastic identification device characterized by that.   3. The plastic identification device according to claim 1, wherein the shorter one of the first wavelength and the second wavelength is shorter than 630 nm and longer than 400 nm. 4.   3. The plastic identifying apparatus according to claim 2, wherein an irradiation intensity of the second laser light is higher than an irradiation intensity of the first laser light. A first laser light source for irradiating the first laser light; and a second laser light source for irradiating the second laser light. Including
The multi-channel spectroscopic unit is separated, and a first multi-channel spectrometer that acquires a Raman scattering spectrum by the first laser light, and a second multi-channel that acquires a Raman scattering spectrum by the second laser light Including a spectroscope,
5. The plastic identification device according to claim 1, wherein the data processing device receives a Raman scattering spectrum from the first and second multichannel spectrometers. 6.   The plastic identifying apparatus according to claim 1, further comprising a transport unit configured to transport the plastic piece that is identified by the material.   After irradiating the plastic with the first laser beam and detecting the Raman scattering spectrum scattered from the plastic, when the intensity of the peak position of one or more predetermined points is less than the predetermined intensity, the wavelength is greater than that of the first laser beam. Is used to detect a Raman scattering spectrum by irradiating a short second laser beam, and to identify the plastic material by comparing the detected Raman scattering spectrum with the standard Raman spectrum of the plastic. Method.   After irradiating the plastic with the first laser light and detecting the Raman scattering spectrum scattered from the plastic, when the intensity of the peak position of one or more predetermined points is higher than the predetermined intensity, the wavelength is higher than that of the first laser light. Is characterized by detecting a Raman scattering spectrum by irradiating a long second laser beam and identifying the material of the plastic by comparing the detected Raman scattering spectrum with the standard Raman spectrum of the plastic. Method.

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