Cellulose Composite Discrimination Method and Device for Composite Resin

Abstract

The present invention provides a method and apparatus for discriminating the compounding of cellulose in a composite resin, which can discriminate the compounding of cellulose regardless of the type of composite resin even at low concentrations. Infrared light is irradiated onto a composite resin containing cellulose, and the reflected light from the composite resin irradiated with the light is received. Among the reflection or absorption spectra obtained from the reflected light, normalization is performed at the peak position that is the largest among the peaks at 2800 cm-1 or higher and 3000 cm-1 or lower, which is the C-H stretching peak caused by the composite resin, to obtain a reflection or absorption spectrum for discrimination. Using the reflection or absorption spectrum, the ratio value of the spectral intensity (background intensity) below 1000 cm-1 at a position different from the wave number of the peak showing the resin of the discriminated resin type is obtained according to the discriminated resin type. By using the ratio of the obtained spectral intensity (i.e., the background intensity), the compounding of cellulose compounded in the composite resin can be discriminated with high accuracy.

Description

Technical Field

[0001] The present invention relates to a composite discrimination method and apparatus for cellulose contained in a composite resin obtained by compounding resin and cellulose, for a discrimination object formed by aggregating a plurality of small pieces. Background Art

[0002] Due to large-scale consumption and wasteful economic activities, global environmental problems such as global warming and resource depletion have arisen.

[0003] Under such circumstances, in order to build a resource recycling-oriented society, in Japan, the Home Appliance Recycling Law has been implemented since April 2001. Through the Home Appliance Recycling Law, there is an obligation to recycle used home appliances (such as air conditioners, televisions, refrigerators, freezers, washing machines, or clothes dryers, etc.). As a result, after used home appliances are broken into small pieces in a home appliance recycling factory, they are discriminated and recycled according to material types using magnetism, wind power, vibration, etc., and re-resourced as recycled materials. Among resin materials, polypropylene (hereinafter referred to as PP), polystyrene (hereinafter referred to as PS), or acrylonitrile-butadiene-styrene (hereinafter referred to as ABS) are widely used in home appliances. By using a discrimination device based on the light absorption characteristics in the near-infrared region (wavenumber range 4000 - 10000 cm -1 ) of the molecular structure of the resin, discrimination and recycling are carried out according to resin types.

[0004] This discrimination device can irradiate the small pieces conveyed by a conveyor with light containing the near-infrared region, detect the reflection or absorption spectrum from the resin in a non-contact manner, and discriminate the resin type, so it can perform discrimination processing on a large number of small pieces.

[0005] In recent years, from the perspective of environmentally friendly materials, natural-derived materials have received attention. In particular, home appliances using composite resins in which cellulose is compounded with resin have started to be sold. It is expected that cellulose will expand in a large number of home appliances in the future, and it can be expected that the compounding ratios, etc. of each company will be different. Therefore, it is expected that in the future, it will be necessary to discriminate substances containing two or more organic compounds such as composite resins in which cellulose is compounded with resin.

[0006] In Patent Document 1, a method is proposed that takes into account the above-mentioned problem related to the discrimination method of substances compounded with multiple organic compounds. In the technique described in Patent Document 1, in order to analyze the composition in an unvulcanized rubber composition, a filler gelation treatment is performed, and the reflection spectrum shown in Figure 8 is obtained by Fourier transform infrared spectroscopy. Based on the obtained spectrum, the peaks (960 cm -1 , 903 cm -1 , 697 cm-1 ), and the determination is made therefrom. In addition, in Patent Document 1, without subjecting the unvulcanized rubber composition to filler gelation treatment, a spectrum in which not only peaks derived from styrene-butadiene rubber but also peaks derived from natural rubber are mixedly present is detected.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-40508

[0010] Technical Problem to be Solved by the Invention

[0011] When recycling a resin composite with cellulose, it is necessary to discriminate and separate the composite resin in a non-destructive manner and according to the proportion of the cellulose incorporated.

[0012] However, in the compositional analysis as in Patent Document 1, in the discrimination of a composite resin formed of a resin and cellulose, the peak intensity of cellulose is weak, and furthermore, the peaks of the resin, cellulose, and antioxidant added during molding overlap with each other. Therefore, it is difficult to derive the composite ratio of cellulose based on the ratio of the peak intensities. More specifically, a molded composite resin commonly used in home appliances contains an antioxidant. The peak of this antioxidant overlaps with the O-H stretch, which is a peak specific to cellulose. The C-O-C stretch, which is another peak specific to cellulose, also overlaps with the peak position specific to the resin depending on the type of composite resin. Therefore, there is a problem that it is difficult to make a determination based on the peak values of the obtained spectrum. Furthermore, since the peak intensity of cellulose does not appear sharp, there is also a problem that it is difficult to discriminate the difference between the spectrum of a composite resin with a composite rate of 10% or less and the spectrum of the resin alone. Summary of the Invention

[0013] Means for Solving the Problem

[0014] The present invention is for solving the above-mentioned conventional problems, and an object thereof is to provide a method and an apparatus for discriminating cellulose composite of a composite resin, which, when discriminating the cellulose composite of a composite resin using a reflection or absorption spectrum in the mid-infrared to far-infrared region (wavenumber range 500 - 4000 cm -1 ), instead of focusing on the peak values of the obtained spectrum, focuses on the ratio value of the spectral intensity (i.e., background intensity) at a position different from the wavenumber at which the peak derived from the resin appears, and discriminates the cellulose composite regardless of the type of composite resin by using the increase or decrease of the ratio value of the spectral intensity (i.e., background intensity) at a position different from the wavenumber at which the peak derived from the resin appears, even at low concentrations.

[0015] To solve the above problems, a method for discriminating cellulose composites in a composite resin according to one aspect of the present invention

[0016] irradiates infrared light onto a composite resin containing cellulose,

[0017] receives reflected light from the composite resin irradiated with the infrared light,

[0018] discriminates the resin type of the composite resin based on the reflection or absorption spectrum obtained from the reflected light,

[0019] uses the spectrum obtained by normalizing the intensity of the peak position having the maximum intensity among the peaks in the range of 2800 cm -1 or more and 3000 cm -1 or less, which is the wave number of the C-H stretching peak caused by the composite resin, to obtain the ratio value of the spectral intensity (i.e., background intensity) at a position below 1000 cm -1 and different from the wave number of the peak of the resin showing the resin type determined above,

[0020] uses the spectrum of a sample of a single resin that is the resin contained in the composite resin and has been previously obtained, obtains the ratio value of the spectral intensity (i.e., background intensity) by the same method as for the composite resin in advance, and discriminates the cellulose composite in the composite resin by comparing these values.

[0021] To solve the above problems, a device for discriminating cellulose composites in a composite resin according to another aspect of the present invention includes:

[0022] an irradiation unit that irradiates infrared light onto a composite resin containing cellulose;

[0023] a light receiving unit that receives reflected light from the composite resin irradiated with the infrared light;

[0024] a resin type discrimination unit that obtains a reflection or absorption spectrum from the reflected light obtained by the light receiving unit and discriminates the resin type of the composite resin based on the obtained reflection or absorption spectrum;

[0025] a composite discrimination information acquisition unit that uses the spectrum obtained by normalizing the intensity of the peak position having the maximum intensity among the peaks in the range of 2800 cm -1 or more and 3000 cm -1 or less, which is the wave number of the C-H stretching peak caused by the composite resin, to obtain the ratio value of the spectral intensity (i.e., background intensity) at a position below 1000 cm -1The ratio value of the spectral intensity (i.e., background intensity) below and at a position different from the wave number of the peak of the resin showing the identified resin type as the composite discrimination information; and

[0026] A composite resin discrimination unit discriminates the composite of cellulose in the composite resin by comparing the ratio value of the spectral intensity (i.e., background intensity) obtained by the composite discrimination information acquisition unit and the ratio value of the spectral intensity (i.e., background intensity) obtained in advance by the same method as the composite resin using the spectrum of a sample of a single resin that is the resin contained in the composite resin.

[0027] Advantages of the Invention

[0028] As described above, according to the method and device for discriminating the composite of cellulose in the composite resin according to the mode of the present invention, using the reflection or absorption spectrum of the object to be discriminated, select a wave number at a position different from the wave number of the peak position of the resin among the wave numbers below 1000 cm -1 Obtain the ratio of the spectral intensity (i.e., background intensity) at the selected wave number, and using the increase and decrease of the ratio value of the obtained spectral intensity (i.e., background intensity), it is possible to accurately discriminate the composite of cellulose composite in the composite resin. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the device for discriminating the composite of cellulose in the composite resin in Embodiments 1 and 2 of the present invention.

[0030] Figure 2 It is a schematic diagram of the detection area in Embodiments 1 and 2 of the present invention.

[0031] Figure 3 It is a flowchart of the method for discriminating the composite of cellulose in the composite resin in Embodiment 1 of the present invention.

[0032] Figure 4A It is a curve graph of the composite resin spectrum obtained in Embodiment 1 of the present invention.

[0033] Figure 4B It is a curve graph of the reflectance and wave number where the wave numbers of the peak intensities of PP, ABS, and PS are different in Embodiment 1 of the present invention.

[0034] Figure 5 It is a curve graph showing the relationship of the penetration depth caused by the difference in refractive index in Embodiment 2 of the present invention.

[0035] Figure 6 It is a flowchart of the method for discriminating the composite of cellulose in the composite resin in Embodiment 2 of the present invention.

[0036] Figure 7 This is a graph plotting the ratio of the peak intensity of reflectance at a wavenumber of 500 cm of PP and cellulose in Embodiment 2 of the present invention against the compounding ratio of cellulose. -1

[0037] Figure 8 This is a graph of the reflectance spectrum in the case of subjecting an unvulcanized rubber composition to a filler gelation treatment in the discrimination of a conventional composite resin described in Patent Document 1.

[0038] Explanation of Reference Numerals

[0039] 1: Composite resin discrimination device;

[0040] 2: Composite resin;

[0041] 3: Irradiating light;

[0042] 4: Reflected light;

[0043] 5: Placing part;

[0044] 6: Specimen fixing mechanism;

[0045] 7: Detection area;

[0046] 7a: Prism;

[0047] 8: Infrared detection unit;

[0048] 8a: Irradiating part;

[0049] 8b: Light receiving part;

[0050] 9: Digital data conversion part;

[0051] 10: Arithmetic processing part;

[0052] 110: Resin type discrimination part;

[0053] 110a: Spectrum intensity acquisition part;

[0054] 110b: Correlation acquisition part;

[0055] 120: Spectrum evaluation part;

[0056] 120a: Normalization processing part;

[0057] 120b: Composite discrimination information acquisition part;

[0058] 130: Composite resin discrimination part. Detailed Embodiment

[0059] Hereinafter, with reference to Figures 1 to 7The accompanying drawings illustrate embodiments of the present invention in detail.

[0060] (Embodiment 1)

[0061] Embodiment 1 of the present invention relates to a method and apparatus for discriminating cellulose composites in composite resins. For example, infrared light is irradiated onto a composite resin containing cellulose such as cellulose fiber, and the reflected light from the composite resin irradiated with infrared light is received. Based on the reflection or absorption spectrum obtained from the reflected light, the type of resin in the composite resin (i.e., resin type) is discriminated. Among the reflection or absorption spectra obtained from the reflected light, the intensity of the peak position with the maximum intensity in the range of wavenumbers above 2800 cm -1 and below 3000 cm -1 is normalized, and the spectrum obtained by normalization is used to obtain the ratio of the spectral intensity (i.e., background intensity) at a position below 1000 cm -1 in the spectrum and at a position different from the wavenumber of the peak of the resin showing the resin type determined above. Using the spectrum of a sample of a single resin that is the resin contained in the composite resin and has been previously obtained, the ratio of the spectral intensity (i.e., background intensity) is obtained in the same manner as for the composite resin in advance as composite discrimination information. By comparing these values, the composite of cellulose in the composite resin is discriminated.

[0062] Here, in Embodiment 1, instead of comparing the peak intensity values, the background intensity values are compared.

[0063] As the definition of peak intensity, it refers to the intensity at which the spectrum sharpens at the wavenumber where the peak of the resin appears in the obtained spectroscopic intensity.

[0064] In contrast, as the definition of background intensity, it refers to the spectral intensity at a wavenumber different from the peak appearing from the material (material-derived peak) in the obtained spectroscopic intensity.

[0065] The intensity ratio is used because normalization is performed using the peak of the resin from the original data.

[0066] Hereinafter, Embodiment 1 will be described in detail. In Embodiment 1, it is determined whether cellulose is present.

[0067] As Figure 1 shown, the composite resin discrimination apparatus 1 at least includes: an infrared detection unit 8 having a detection area 7, an irradiation unit 8a, and a light receiving unit 8b; and an arithmetic processing unit 10. Further, the composite resin discrimination apparatus 1 may also be provided with a placement unit 5.

[0068] As an example, the placement unit 5 shows an example of a belt conveyor, where the belt moves at a fixed speed, and the composite resin 2 as a specimen is placed on the upper surface and can be transferred. Through this placement unit 5, the composite resin 2 is transferred along the length direction of the placement unit 5 to the detection area 7, and the transfer stops when the composite resin 2 is located in the detection area 7.

[0069] The infrared detection unit 8 has the function of irradiating infrared rays to the composite resin 2 in the detection area 7 and the function of receiving the reflected light 4 from the composite resin 2 of the irradiated light 3.

[0070] In the detection area 7, as Figure 2 shown, with the specimen fixing mechanism 6, the composite resin 2 is brought into close contact with and fixed to the upper surface of the placement unit 5 toward the prism 7a side. As an example, the specimen fixing mechanism 6 is a member like a rod that presses the composite resin 2 onto the upper surface of the placement unit 5 from above. In the detection area 7, as an example of the infrared detection unit 8, it at least includes an irradiation unit 8a as a mechanism for irradiating infrared light as an example of the irradiated light 3 from below upward and a light receiving unit 8b as a mechanism for detecting the reflected light 4. Therefore, the irradiated light 3 from the irradiation unit 8a irradiates the lower surface of the composite resin 2 through the prism 7a and the placement unit 5, and the reflected light 4 reflected from the lower surface of the composite resin 2 is received by the light receiving unit 8b through the placement unit 5 and the prism 7a. The information obtained by being received by the light receiving unit 8b is input to the arithmetic processing unit 10. Therefore, the placement unit 5 is made of a material through which infrared light and its reflected light can pass.

[0071] In addition, in order to utilize the light absorption characteristics based on the molecular structure of the composite resin 2, the irradiated light 3 and the reflected light 4 respectively need to include a frequency band of 500 - 4000 cm -1 .

[0072] The infrared detection unit 8 is connected to the arithmetic processing unit 10 via the digital data conversion unit 9.

[0073] The digital data conversion unit 9 converts the electrical signal output by the infrared detection unit 8 based on the reflected light 4 into digital data.

[0074] The arithmetic processing unit 10 discriminates the composite resin type of the composite resin 2 of the object to be discriminated based on the reflection or absorption spectrum of the composite resin 2 based on the digital data obtained from the reflected light 4 by the light receiving unit 8b, and then discriminates the composite of cellulose. Specifically, in the arithmetic processing unit 10, they are discriminated based on the digital data output from the digital data conversion unit 9.

[0075] Therefore, the arithmetic processing unit 10 generally includes a resin type discrimination unit 110, a spectrum evaluation unit 120, and a composite resin discrimination unit 130.

[0076] The resin type discrimination unit 110 includes a spectral intensity acquisition unit 110a and a correlation acquisition unit 110b.

[0077] The spectral evaluation unit 120 includes a normalization processing unit 120a and a composite discrimination information acquisition unit 120b.

[0078] The resin type discrimination unit 110 discriminates the resin type of the composite resin 2.

[0079] The spectral intensity acquisition unit 110a of the resin type discrimination unit 110 acquires the spectral intensity based on the reflected light 4. That is, first, the analog data of the reflected light 4 received by the light receiving unit 8b is converted from the light receiving unit 8b into digital data by the digital data conversion unit 9 and then input to the spectral intensity acquisition unit 110a of the arithmetic processing unit 10. In the digital data conversion unit 9, the analog data of the reflected light 4 is converted into digital data of the reflected light 4. In the spectral intensity acquisition unit 110a, based on the input digital data of the reflected light 4, the reflection or absorption spectrum of the composite resin 2 is calculated. Here, for example, in order to represent the relationship between reflection and spectral intensity or the relationship between absorption spectrum and spectral intensity, relationship information such as in the form of a table or a curve graph is pre-stored in the spectral intensity acquisition unit 110a for preparation. According to this relationship information, the spectral intensity for discriminating the composite resin is acquired by the spectral intensity acquisition unit 110a based on the calculated reflection or absorption spectrum.

[0080] The correlation acquisition unit 110b of the resin type discrimination unit 110 obtains the correlation based on the spectral intensity for discriminating the composite resin acquired by the spectral intensity acquisition unit 110a, according to the spectral intensity and the spectral waveform of the resin monomer that is included in the composite resin 2 and has been previously acquired. When there are multiple spectral waveforms of the resin monomer, the correlation acquisition unit 110b obtains the respective correlations. Further, in the correlation acquisition unit 110b, the correlation with a high correlation is obtained from the multiple correlations to perform the discrimination of the resin type.

[0081] The normalization processing unit 120a of the spectral evaluation unit 120 normalizes the spectral intensity acquired by the spectral intensity acquisition unit 110a using the peak from the C-H stretch of the resin. That is, the normalization processing unit 120a performs normalization according to the acquired spectral intensity so that the maximum value of the peak intensity in the range of 2800 cm -1 or more and 3000 cm -1 or less becomes 1. A specific example will be described later.

[0082] The composite discrimination information acquisition unit 120b obtains 1000 cm in the acquired spectrum through normalization by the normalization processing unit 120a. -1The ratio of the spectral intensity (i.e., background intensity) at a position below and different from the wavenumber showing the peak derived from the resin is used as composite discrimination information (in other words, composite discrimination target information). Further, the composite discrimination information acquisition unit 120b uses the spectrum of a sample of a single resin that is determined to be the resin contained in the composite resin 2 and is acquired in advance, and acquires in advance the ratio of the spectral intensity (i.e., background intensity) as composite discrimination information (in other words, composite discrimination reference information) by the same method as the composite resin 2.

[0083] Here, when not only the discrimination of the composite is performed, but also the discrimination of the composite ratio is further performed, in the discrimination of the composite ratio, it is necessary to use a sample with a known composite ratio to teach the spectral data. The spectra of resins of the same resin type and with a known composite ratio of a single resin and cellulose are respectively acquired, and a calibration line is created by plotting their background intensity values against the composite ratio. Then, the composite ratio is determined between the background intensity obtained from the unknown sample used in the actual measurement and the calibration line. When making this determination, as a method for determining the composite ratio, correlation coefficient, regression analysis, or multivariate analysis is used. In addition, as described above, the background intensity refers to the spectral intensity at a wavenumber different from the peaks appearing from the material in the acquired spectroscopic intensity. Therefore, by using the background intensity, it is possible to evaluate without mixing of the peaks peculiar to the material composition, and thus it is possible to evaluate the ratio of cellulose with high accuracy.

[0084] The composite resin discrimination unit 130 discriminates the composite of cellulose in the composite resin 2 by comparing the ratio values of these peak intensities (i.e., background intensities) in the composite discrimination information acquisition unit 120b. Specifically, the composite resin discrimination unit 130 respectively acquires the ratio values of the spectral intensities (i.e., background intensities) at positions different from the wavenumber showing the peak derived from the resin between the single resin and the composite resin. As a result, when the ratio value of the spectral intensity of the resin to be discriminated as the composite discrimination target information is larger than the ratio value of the spectral intensity of the single resin as the composite discrimination reference information, it is discriminated as a composite resin, that is, the composite of cellulose.

[0085] As a method for making the discrimination, the ratio value of the spectral intensity (i.e., background intensity) at a position different from the wavenumber showing the peak derived from the resin when measuring the single resin and the cellulose composite resin is defined as a threshold value. When discriminating the presence or absence of cellulose based on the value of the threshold value specified in advance and the value obtained by actual measurement, relevant information is required.

[0086] Here, the so-called relevant information refers to the difference from the value of the threshold value. As an example of the relevant information, it is conceivable to create a spectral database, the difference between the acquired spectrum and the value of the threshold value, etc.

[0087] The threshold value is set according to the background intensity obtained from the spectrum of the cellulose composite resin. Using a cellulose composite resin with a known composite ratio to be discriminated, measurements are pre - carried out to obtain the background intensity of the wavenumber that does not coincide with the peaks specific to the resin and cellulose. This background intensity is used as the threshold value to determine the presence or absence of cellulose.

[0088] Here, use Figure 3 The discrimination method for the composite resin according to Embodiment 1 will be described.

[0089] Figure 3 It is a flowchart showing the processing steps of the discrimination method for the composite resin according to Embodiment 1.

[0090] First, in step S01, the sample of the composite resin 2 combined with cellulose is transferred by the placement unit 5, and the composite resin 2 combined with cellulose is stopped at a position above the ATR (Attenuated Total Reflection) prism 7a in the detection area 7. At this position, with Figure 2 the sample fixing mechanism 6 in it, a pressing force is applied to the composite resin 2 in the direction of the prism 7a to apply a load, so that the composite resin 2, the placement unit 5, and the prism 7a are in close contact. Here, the reason for using the ATR prism is that if it is not FT - IR using an ATR prism (i.e., Fourier transform infrared spectroscopy), the background intensity used in the analysis will not appear in principle.

[0091] Next, in step S02, infrared light as the irradiation light 3 is irradiated to the sample of the composite resin 2 combined with cellulose in the detection area 7 via the prism 7a and the placement unit 5 from the irradiation unit 8a as shown in Figure 1 .

[0092] Next, in step S03, when the irradiation light 3 irradiated from the irradiation unit 8a in step S02 is reflected as the reflected light 4 on the surface of the composite resin 2, the reflected light 4 is received and detected by the light receiving unit 8b via the placement unit 5 and the prism 7a.

[0093] Next, in step S04, the information of the reflected light 4 detected by the light receiving unit 8b in step S03 is Fourier - transformed by the digital data conversion unit 9 and input as digital data to the spectral intensity acquisition unit 110a of the resin type discrimination unit 110 in the arithmetic processing unit 10. In the spectral intensity acquisition unit 110a, based on the input digital data, a spectrum in the mid - and far - infrared region is calculated. In the spectral intensity acquisition unit 110a, based on the calculated reflection or absorption spectrum, for example, using relationship information in the form of a table or a curve showing the relationship between the reflection or absorption spectrum and the spectral intensity, the spectral intensity for discriminating the composite resin is obtained.

[0094] Next, in step S05, in the relevance acquisition unit 110b of the resin type discrimination unit 110, the relevance is obtained based on the spectral intensity acquired in step S04 and the spectral waveforms of the resin monomers that are one or more resins included in the composite resin 2 and have been acquired in advance. When there are multiple spectral waveforms of the resin monomers, the relevance acquisition unit 110b calculates the respective relevance. Further, in the relevance acquisition unit 110b, the relevance with a high relevance is obtained from the multiple relevances to discriminate the resin type. In the following Figure 4A example, PP is discriminated as the resin type.

[0095] The relevance here refers to the correlation coefficient used when determining the type of resin with which cellulose is compounded by comparing the spectral database with the acquired spectrum. Based on the result, the base resin type is determined. Figure 4A The spectra of the PP monomer resin and the PP resin compounded with cellulose are shown. Figure 4B are the spectral data of PP, ABS, and PS. The wave number representing the peak intensity of PP is completely different from the wave numbers of the peak intensities of ABS or PS. Here, compared with the relevance of PP, the relevance of resins other than PP, i.e., ABS or PS, becomes lower.

[0096] Next, in step S06, in the normalization processing unit 120a of the spectral evaluation unit 120 of the arithmetic processing unit 10, normalization is performed based on the acquired spectral intensity so that the maximum value of the peak intensity in the range of -1 above 2800 cm -1 and below 3000 cm Figure 4A shows the spectrum of the composite resin compounded with PP and cellulose. In the case of PP, as an example, the normalization processing unit 120a normalizes with the peak intensity at the wave number 2917 cm -1 . According to this Figure 4A , at the peak positions of the O-H stretching and C-O-C stretching, which are the peaks peculiar to cellulose, the normalization processing unit 120a performs normalization so that the maximum value of the peak intensity in the range of -1 above 2800 cm -1 and below 3000 cm Figure 4A (i.e., the range between the two vertical dotted lines in

[0097] becomes 1. It can be seen that the difference in the reflectance peak intensity ratio derived by performing this normalization is almost zero among the spectra and cannot be distinguished. -1 above 2800 cm -1Normalize in such a way that the maximum value of the peak intensity within the following range becomes 1. Compared with before the processing, the change in the background intensity ratio can be clarified.

[0098] Next, in step S07, in the composite discrimination information acquisition unit 120b of the spectral evaluation unit 120, a wavenumber that does not overlap with the resin (PP in this example) of the previously discriminated resin type is selected on the low wavenumber side (1000 cm -1 or less). That is, the value of the wavenumber selected here needs to be determined by the composite discrimination information acquisition unit 120b not to overlap with the peak position corresponding to the resin type discriminated in step S05. In Figure 4A , the spectrum of a sample in which PP and cellulose are compounded is shown. In Figure 4A order to calculate the background intensity at a wavenumber of 1000 cm -1 or less, the composite discrimination information acquisition unit 120b needs to select a region that does not overlap with the peak wavenumber of PP, which is the resin of the discriminated resin type. That is, a wavenumber that does not overlap with the peaks of CH2=CH (wavenumber 990 cm -1 ), HC=CH (wavenumber 970 cm -1 ), CH2COOH (wavenumber 940 cm -1 ), CH (wavenumber 840 cm -1 ), CH (wavenumber 810 cm -1 ), CH2 (wavenumber 720 cm -1 ), CH (wavenumber 670 cm -1 ) respectively. In Figure 4A 's embodiment, the composite discrimination information acquisition unit 120b selects the wavenumber 500 cm -1 as a value where the peaks of PP and cellulose do not overlap and the difference in the penetration depth of infrared light is large.

[0099] In this way, the background intensity in the PP embodiment is calculated from a wavenumber different from the peak positions of PP and cellulose. Among them, according to Figure 5 's relationship of the penetration depth, as the wavenumber, 500 cm -1 where the change caused by the refractive index within the spectrum is the largest is also selected.

[0100] In addition, the ratio of the spectral intensity at a position different from the wavenumber where the peak originating from the resin appears is defined as the background intensity ratio, and the ratio of the spectral intensity at the wavenumber where the peak originating from the resin appears is defined as the peak intensity ratio.

[0101] Next, in step S08, the composite discrimination information acquisition unit 120b calculates the value of the background intensity ratio among the selected wave numbers as the composite discrimination information. Here, using the spectrum of the sample of the single resin that is the resin contained in the composite resin 2 and has been obtained in advance, by the same method as that of the composite resin 2, the composite discrimination information acquisition unit 120b obtains the value of the background intensity ratio in advance as the composite discrimination information. As an example, in Figure 4A the wave number values are plotted on the horizontal axis, and the value of the reflectance peak intensity ratio according to the cellulose composite ratio at the wave number 500 cm selected in step S07 is plotted on the vertical axis. -1 In this case, it can be seen that for the resin of PP, the reflectance peak intensity ratio is 0.053 when the cellulose content is 0%, 0.070 when the cellulose content is 5%, and 0.093 when the cellulose is compounded at 10%. As the cellulose composite ratio increases, the value of the reflectance peak intensity ratio increases. The composite resin discrimination unit 130 obtains this information in advance.

[0102] Next, in step S09, the proportion of cellulose of the same resin type as the composite resin 2 to be discriminated is determined in advance. The composite discrimination information acquisition unit 120b separately derives in advance a plurality of background intensity ratios in the region below 1000 cm -1 for the samples with known proportions, and uses them as thresholds. These multiple thresholds are obtained in advance and placed in the composite resin discrimination unit 130 of the arithmetic processing unit 10. In the composite resin discrimination unit 130, by comparing the value of the background intensity ratio obtained in step S08 with the aforementioned multiple thresholds respectively, if the background intensity ratio is between the multiple thresholds, the cellulose composite and the composite ratio can be discriminated. For example, when the value obtained in step S08 is larger than the first threshold and smaller than the second threshold among the aforementioned multiple thresholds, it can be discriminated that the cellulose with the amount corresponding to X% of the second threshold is contained, there is cellulose composite, and the composite ratio is X%.

[0103] In this way, by setting one threshold and making a discrimination based on the comparison with this threshold. Regarding the embodiments of the cellulose composite ratio for each percentage, they are plotted in Figure 7 As an example, if the discrimination criterion is set to 5%, then according to Figure 7 the threshold is set to 0.06944, and if it is above this value, it can be discriminated that the cellulose is compounded by 5% or more.

[0104] As described above, according to Embodiment 1, using the reflection or absorption spectrum of the composite resin 2 as the object to be discriminated, 1000 cm is selected according to the discriminated resin type -1For a wavenumber different from the peak position of the resin among the following wavenumbers, the peak intensity ratio at this wavenumber is calculated and compared in advance with the peak intensity ratio of a known resin without composite cellulose, so that the composite and composite ratio of cellulose composite in the composite resin 2 can be discriminated with high precision.

[0105] The reason why such high-precision discrimination can be performed is as follows.

[0106] In the analysis based on the conventional composition, in the discrimination of the composite resin formed by the resin and cellulose, the peak intensity of cellulose is weak, and furthermore, the peaks of the resin, cellulose, and the antioxidant added during molding overlap with each other. Therefore, it is difficult to derive the composite ratio of cellulose from the ratio of the peak intensities. In contrast, in the first embodiment, by using the background intensity, it is possible to evaluate without the mixing of the peaks peculiar to the material composition, and thus the ratio of cellulose can be evaluated with high precision.

[0107] (Embodiment 2)

[0108] In the first embodiment, according to the discriminated resin type, a wavenumber below 1000 cm -1 For a wavenumber different from the peak position of the resin among the following wavenumbers, the background intensity ratio at this wavenumber is calculated and compared in advance with the background intensity ratio of a known resin without composite cellulose, to determine whether cellulose is composite in the composite resin 2.

[0109] However, the present invention is not limited to this, and there is also the following method. That is, instead of comparing the background intensity ratios, in the composite discrimination information acquisition unit 120b, the background intensity is acquired in advance according to the composite resin with a known composite ratio and a calibration line is drawn, and according to the degree of correlation with the calibration line, the composite and composite ratio are discriminated by the composite resin discrimination unit 130. That is, in the composite discrimination information acquisition unit 120b, instead of comparing the background intensity ratios, a calibration line related to the background intensity derived in advance using a sample with a known cellulose composite ratio is created. Next, according to the level of the degree of correlation between the calibration line and the value of the acquired background intensity, the composite and composite ratio are discriminated by the composite resin discrimination unit 130.

[0110] In this method, the evaluation is performed not by the composition of the substance but by the increase or decrease in the intensity of the background caused by the difference in refractive index. Therefore, even in substances where it is difficult to have peaks caused by the composition, the composite and composite ratio can be more accurately discriminated, which is excellent in this regard.

[0111] This background intensity is determined by the relationship of the penetration depth of infrared light based on the difference in refractive index between the composite resin and cellulose. Figure 5Shows the relationship of the penetration depth caused by the difference in refractive index. The refractive index of PP is 1.48. In addition, the refractive index of cellulose is 1.58. As a result, as cellulose is compounded, the penetration depth of the incident light becomes deeper, and as this depth increases, the background intensity increases on the low wavenumber side. The mathematical formula representing the relationship between the penetration depth and the refractive index of the sample is as follows.

[0112] [Equation 1]

[0113]

[0114] dp: Penetration depth

[0115] λ: Wavelength

[0116] θ: Angle of incidence

[0117] n1: Refractive index of the prism

[0118] n2: Refractive index of the sample

[0119] As factors determining this penetration depth, there are wavelength, angle of incidence, refractive index of the prism, and refractive index of the sample. Regarding the wavelength, if the wavenumber (500 - 4000 cm -1 ) is converted to wavelength, the wavelength is 20 μm at a wavenumber of 500 cm -1 , and the wavelength is 2.5 μm at a wavenumber of 4000 cm -1 . Therefore, the wavelength becomes longer on the low wavenumber side and the penetration depth increases. Depending on the angle of the incident light, there are restrictions on the refractive index of the sample that can be discriminated, so the incident angle needs to be determined according to the sample to be measured. In this case, the incident angle of the irradiated light is 45 degrees. Regarding the prism, the one with a lower refractive index has a deeper penetration depth, so diamond with the lowest refractive index among the raw materials used is also used. In this case, the refractive index is 2.4. The refractive index of the sample is the refractive index of the composite resin used in this measurement. The refractive index of cellulose is 1.58, PP as a composite resin commonly used in household appliances is 1.48, PS is 1.60, and ABS is 1.51. The penetration depth of infrared light changes according to the refractive index of the material. Therefore, if this mathematical formula is considered, if the refractive index increases, the penetration depth of the irradiated light also becomes deeper, and accordingly, the reflected light that is reflected and returns also becomes larger. As a result, the background intensity increases, and this increase and decrease are used for determination. Therefore, it is considered that discrimination can also be performed even when these composite resins and cellulose are compounded.

[0120] According to the above relationship, in Figure 6 shows a flowchart for discriminating the compounding ratio using a calibration line. Steps S01 to S07 are the same as steps S01 to S07 in Embodiment 1.

[0121] In step S08, in the same manner as step S08 of Embodiment 1, the composite discrimination information acquisition unit 120b calculates the value of the reflectance peak intensity ratio among the wavenumbers at which the resin and cellulose do not overlap at a wavenumber of 1000 cm -1 as the composite discrimination information. Figure 7 is a graph in which the values of the reflectance peak intensity ratios at a wavenumber of 500 cm -1 of PP and cellulose are plotted according to the composite ratio of cellulose. According to this result, if an approximate line is plotted in the composite discrimination information acquisition unit 120b, an approximate curve represented by the mathematical formula of (2) will be plotted.

[0122] [Mathematical formula 2]

[0123] Reflectance peak intensity ratio: I = 0.0532e 0.0561x …(2)

[0124] i: Reflectance peak intensity ratio

[0125] x: Composite ratio

[0126] In step S09, it is described how to make the intensity value calculated in step S08 fall within the composite ratio in the composite discrimination information acquisition unit 120b. In order for the composite discrimination information acquisition unit 120b to calculate the composite ratio as the composite discrimination information based on the intensity value, a reference value for the intensity is required. As a method for determining this reference value, the composite discrimination information acquisition unit 120b needs to create a calibration line based on the data of the relationship between the composite ratio of cellulose measured from a sample known in advance and the background intensity at the wavenumber selected in step S07 according to the measurement data.

[0127] In step S10, in the composite resin discrimination unit 130, for the created calibration line, it is applied at a point with a high intensity related to the value of the background intensity obtained by measuring an unknown sample, thereby deriving the composite ratio.

[0128] As described above, according to the composite ratio discrimination method and apparatus according to Embodiment 2, using the reflection or absorption spectrum in the object to be discriminated, a wavenumber different from the peak position derived from the resin among the wavenumbers of 1000 cm -1 or less is selected according to the resin type determined, the peak intensity ratio at this wavenumber is calculated, and instead of comparing the peak intensity ratios, the background intensity is obtained in advance from a composite resin with a known composite ratio and a calibration line is plotted. According to the degree of correlation with the calibration line, it is possible to accurately discriminate the composite of cellulose and the composite ratio in the composite resin 2.

[0129] The reason why such accurate discrimination can be performed is as follows.

[0130] In the analysis based on the previous composition, in the discrimination of the composite resin formed of resin and cellulose, the peak intensity of cellulose is weak, and furthermore, the peaks of resin, cellulose, and the antioxidant added during molding overlap with each other. Therefore, it is difficult to derive the compounding ratio of cellulose from the ratio of peak intensities. In contrast, in the second embodiment, by using the background intensity, it is possible to evaluate without mixing of the peaks peculiar to the material composition, and thus the ratio of cellulose can be evaluated with high accuracy.

[0131] In addition, by appropriately combining any of the various embodiments or modification examples described above, their respective effects can be exerted. Furthermore, combinations of embodiments with each other, combinations of examples with each other, or combinations of embodiments and examples can be made, and combinations of features in different embodiments or examples can also be made.

[0132] [Industrial Applicability]

[0133] The method and apparatus for discriminating cellulose compounding of the composite resin according to the foregoing aspect of the present invention can quickly discriminate the cellulose compounding of the composite resin containing cellulose. Therefore, among a plurality of objects to be discriminated, the composite resin having a high cellulose compounding ratio can be used for a recycling process or the like that requires high purification.

Claims

1. A method for discriminating the cellulose composite of a composite resin, Irradiate infrared light on the composite resin containing cellulose, Receive the reflected light from the composite resin irradiated with the infrared light, Discriminate the resin type of the composite resin according to the reflection or absorption spectrum obtained from the reflected light, Using the spectrum obtained by normalizing the intensity of the peak position that becomes the maximum intensity among the reflection or absorption spectra obtained from the reflected light, within the range of wave numbers of 2800 cm -1 or more and 3000 cm -1 or less, and obtaining the ratio value of the spectral intensity, i.e., the background intensity, at a position below 1000 cm -1 in the spectrum and at a position different from the wave number of the peak of the resin showing the identified resin type Use the spectrum of a sample of a single resin that is the resin contained in the composite resin and has been previously obtained, and obtain the ratio value of the spectral intensity, that is, the background intensity, by the same method as the composite resin, By comparing these values, discriminate the cellulose composite in the composite resin.

2. The method for discriminating the cellulose composite of a composite resin according to claim 1, wherein, Create a calibration line related to the background intensity derived by previously using a sample with a known cellulose composite ratio, Discriminate the composite and the composite ratio according to the degree of correlation between the calibration line and the obtained value of the background intensity, Instead of: After obtaining the peak intensity ratio value at a position below 1000 cm -1 and different from the wavenumber of the peak of the resin showing the resin type determined above as composite discrimination information, Use the spectrum of a sample of a single resin that is the resin contained in the composite resin and has been previously obtained, and obtain the ratio value of the spectral intensity, that is, the background intensity, by the same method as the composite resin. By comparing the ratio values of the spectral intensity, that is, the background intensity, at positions different from the wave numbers where the peaks derived from these resins appear, discriminate the cellulose composite in the composite resin.

3. A device for discriminating the cellulose composite of a composite resin, comprising: An irradiation unit that irradiates infrared light on the composite resin containing cellulose; A light receiving unit that receives the reflected light from the composite resin irradiated with the infrared light; A resin type discrimination unit that obtains a reflection or absorption spectrum from the reflected light obtained by the light receiving unit, and discriminates the resin type of the composite resin according to the obtained reflection or absorption spectrum; The composite discrimination information acquisition unit uses the spectrum obtained by normalizing the intensity of the peak position with the maximum intensity among the peaks in the range of 2800 cm -1 or more and 3000 cm -1 or less in the reflection or absorption spectrum obtained from the reflected light, and acquires the ratio value of the spectral intensity at a position of 1000 cm -1 or less and at a position different from the wave number of the peak of the resin showing the resin of the determined resin type as the background intensity as the composite discrimination information; And A composite resin discrimination unit that discriminates the cellulose composite in the composite resin by comparing the ratio value of the spectral intensity, that is, the background intensity, obtained by the composite discrimination information acquisition unit, and the ratio value of the spectral intensity, that is, the background intensity, obtained by the same method as the composite resin using the spectrum of a sample of a single resin that is the resin contained in the composite resin and has been previously obtained.

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