WO2012120779A1 - Recycled resin evaluation device and method for producing recycled article from recycled resin - Google Patents

Abstract

This recycled resin evaluation device is provided with the following: a conveyance device (101) that conveys an evaluation sample (103) of transparent resin; an infrared light source (104) that illuminates the evaluation sample with infrared light; an infrared photoreceptor (129) that receives infrared light reflected from the evaluation sample illuminated with infrared light; an absorption spectrum calculating unit (106b) that calculates the absorption spectrum of the evaluation sample from the reflected infrared light; a thickness measuring unit (106a) that measures the thickness of the evaluation sample; a memory unit (107a) that pre -stores reference data which varies by the thickness of recycled resin; and an evaluation unit (107b) that selects from among the stored reference data the reference data for a recycled resin having a thickness matching the measured thickness, designates the same as selected reference data, and then evaluates whether or not the evaluation sample is the recycled resin on the basis of the absorption spectrum and the selected reference data.

Description

Recycled resin judgment device and method for producing recycled resin recycled product

The present invention relates to a recycling apparatus for determining whether or not an object to be determined is a resin to be recycled, and a method for manufacturing a recycled resin recycled product.

From a mixed plastic that is a mixture containing a plurality of resins such as polystyrene (hereinafter referred to as “PS”), polypropylene (hereinafter referred to as “PP”), acrylonitrile butadiene styrene (hereinafter referred to as ABS), and the like. A technique for determining a resin to be recycled (hereinafter referred to as “recycled resin”) is disclosed in Patent Document 1. The conventional technique will be described with reference to FIG.

The determination apparatus 1 of the recycled resin which concerns on the prior art irradiates infrared light from the light source 4 with respect to the surface of the to-be-determined object 3 conveyed by the conveyance path 2, and is infrared from the surface of the to-be-determined object 3 Reflects light (hereinafter referred to as “infrared reflected light”). The infrared reflected light reflected from the surface of the determination object 3 is imaged by the light receiving unit 7 via the mirror 5 and the polygon mirror 6. At this time, the control device 8 compares the feature quantity of the infrared reflected light imaged by the light receiving unit 7 with the preset feature quantity of the recycled resin. As a result of comparison by the control device 8, when the feature amount of the determination target object 3 matches a preset feature amount of the recycled resin, the determination target component 3 is determined as the recycled resin. In this manner, the recycled resin determination device 1 according to the related art determines, for example, only PS as the recycled resin from the mixed plastic that is the determination target 3.

Japanese translation of PCT publication No. 2002-540397

However, when the object to be determined is a transparent resin, the recycled resin determination device according to the prior art also picks up the infrared reflected light from the conveyance path located below the object to be determined. In this case, the characteristic amount of the determination target acquired based on the captured infrared reflected light overlaps with the characteristic amount of the conveyance path as noise.

If such a feature amount including the influence of noise is used, it cannot be determined whether or not the type of the object to be determined is a recycled resin.

That is, in the conventional determination apparatus for recycled resin, when the determination target is a transparent resin, it is impossible to determine whether the determination target is a recycled resin.

Therefore, the present invention solves the above-described problems, and determines that the determination target, which is a transparent resin, is a recycling resin determination apparatus that determines whether the determination target resin is a recycling target resin, and a recycling target resin. It is an object of the present invention to provide a method for producing a recycled resin recycled product using an object to be determined.

The present invention is configured as follows in order to achieve the above object.

According to one aspect of the present invention, a transport device that transports a determination object that is a transparent resin;
An infrared light source for irradiating the determination object with infrared light;
An infrared light receiving unit that receives infrared reflected light from the object to be determined irradiated with the infrared light; and
An absorption spectrum calculation unit for calculating an absorption spectrum of the object to be determined from the infrared reflected light received by the infrared light receiving unit;
A thickness measuring unit for measuring a measurement thickness which is a thickness of the object to be determined;
A storage unit that stores in advance reference data for different recycled resins for each thickness;
Among the reference data, the reference data for the recycled resin having a thickness corresponding to the measured thickness measured by the thickness measurement unit is selected as selection reference data, and the selection reference data and the absorption spectrum calculation unit are calculated. And a determination unit that determines whether or not the determination target is the recycled resin based on the absorption spectrum.

Further, it is determined by the recycled resin determination device whether the determination object is the recycled resin,
Provided is a method for producing a recycled resin recycled product, in which an article to be judged determined as the recycled resin is molded to produce a recycled resin recycled product.

According to the determination apparatus for recycled resin, it is possible to determine whether or not the transparent resin is a resin to be recycled. Moreover, according to the manufacturing method of this recycled resin recycled product, it becomes possible to manufacture a recycled resin recycled product using the to-be-determined object determined to be a recycling target resin.

These and other objects and features of the invention will become apparent from the following description taken in conjunction with the embodiments with reference to the accompanying drawings. In this drawing,
FIG. 1 is a schematic diagram of a recycled resin determination device according to the first embodiment. FIG. 2 is a schematic diagram of a detection unit according to the first embodiment. FIG. 3 is a diagram illustrating a graph of an absorption spectrum of a determination object having different thicknesses detected by the detection unit according to the first embodiment. FIG. 4A is a block diagram illustrating an absorption spectrum calculation unit and a thickness measurement unit included in the detection unit and a storage unit and a determination unit included in the arithmetic processing unit in the recycled resin determination device according to the first embodiment. Yes, FIG. 4B shows an absorption spectrum calculation unit and a thickness measurement unit included in the detection unit, and a reference data acquisition unit and a storage unit included in the arithmetic processing unit in the determination apparatus for recycled resin according to the modification of the first embodiment. It is a block diagram showing a determination unit, FIG. 5 is a flowchart showing a determination operation by the determination unit according to the first embodiment. FIG. 6 is a graph showing an absorption spectrum obtained by subtracting noise detected when the thickness of the determination object is 2 mm or 3 mm from the absorption spectrum of the determination object having a thickness of 1 mm. FIG. 7 is a graph showing an absorption spectrum obtained by subtracting noise detected when the thickness of the determination object is 1 mm from the absorption spectrum of the determination object having a thickness of 1.5 mm. FIG. 8 is a flowchart showing the operation of the recycled resin determination apparatus according to the first embodiment. FIG. 9 is a schematic diagram illustrating a first modification of the reference unit according to the first embodiment. FIG. 10A is a block diagram showing a recycled resin recycled product manufacturing apparatus according to the second embodiment; FIG. 10B is a cross-sectional view showing a manufacturing process of the manufacturing apparatus of the recycled resin recycled product according to the second embodiment. FIG. 10C is a cross-sectional view showing the manufacturing process of the apparatus for manufacturing recycled resin recycled products according to the second embodiment, FIG. 10D is a cross-sectional view illustrating the manufacturing process of the apparatus for manufacturing recycled resin recycled products according to the second embodiment; FIG. 10E is a perspective view showing a recycled molded product molded in the manufacturing process of the recycled resin recycled product manufacturing apparatus according to the second embodiment; FIG. 11 is a schematic diagram of a determination apparatus for recycled resin according to a conventional technique.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals and description thereof is omitted.

(First embodiment)
FIG. 1 is a schematic diagram of a recycled resin determination apparatus 100 according to the first embodiment.

A conveyor belt 101, which is an example of a transport device, is moving at a constant speed. By the conveyor belt 101, the determination object 103 is transported along the transport path in the longitudinal direction of the conveyor belt 101 from the input area 93A to the selection area 93C through the detection area 93B. When the hopper 102 disposed at the start end of the conveyance path by the conveyor belt 101 vibrates or swings, the determination target 103 is input. The hopper 102 is an example of a loading unit that loads the determination target object 103 onto the conveyor belt 101. A plurality of determination objects 103 stacked on the hopper 102 are sequentially input on the input region 93 </ b> A of the conveyor belt 101 with a certain interval. The conveyor belt 101 is configured in black or a color close to black so that the light is not easily reflected even when the conveyor belt 101 is irradiated with light. Further, the conveyor belt 101 is made of a material (for example, vinyl chloride resin) different from the resin of the determination target 103 so that it can be easily distinguished from the determination target 103 at the time of determination.

The conveyance speed of the object 103 to be determined by the conveyor belt 101 is 3 m / s, and the conveyance direction is the direction of arrow A shown in FIG.

The to-be-determined object 103 is a mixed plastic including a plurality of types of transparent resins, and includes a transparent recycled resin. The determination target object 103 is, for example, a small piece having a side of about 5 mm to several tens of mm, and the thickness of each small piece is, for example, about 0.3 mm to 5.5 mm. That is, the determination target object 103 is a pulverized material and is composed of small pieces having a thickness that can be regarded as substantially constant.

The object 103 is irradiated with infrared light 105 </ b> A from the infrared light source 104, thereby reflecting infrared light that is a characteristic amount of each resin material as infrared reflected light 105.

The infrared light source 104 is disposed on both sides of the detection unit 106 disposed above the detection area 93 </ b> B of the conveyor belt 101 and in a space between the conveyor belt 101 and the detection unit 106. As an example of the infrared light source 104, a halogen lamp that irradiates infrared light (near infrared light) 105A in a broad wavelength band with a wavelength of 1360 to 2500 nm (a wavelength of 1360 nm to 2500 nm) is used. Since the wavelength at which the light absorption phenomenon occurs varies depending on the type of resin, a feature amount is calculated based on the wavelength at which the light absorption phenomenon occurs, and an arithmetic processing unit determines whether the determination target 103 is a recycled resin using the calculated feature amount. The determination is made at 107. The wavelength at which the light absorption phenomenon occurs can be obtained by the detection unit 106 from the absorption spectrum of the infrared reflected light 105 reflected by the determination target 103. Note that a laser light source may be used as the infrared light source 104 as an example.

The infrared reflected light 105 reflected by the determination object 103 is detected by the detection unit 106. The detection result is converted into digital data by the detection unit 106 and then transferred from the detection unit 106 to the arithmetic processing unit 107.

The arithmetic processing unit 107 determines whether the determination target object 103 is a recycled resin based on the detection result of the detection unit 106.

Details of the detection unit 106 and the arithmetic processing unit 107 will be described later.

A pulsed air nozzle 108, which is an example of a sorting unit that blows air onto an object 103 to be judged to be recycled resin (hereinafter referred to as “recycled resin 103a”) above a terminal portion that is a sorting region 93C of the conveyor belt 101. And an air supply source 95 are arranged. Based on an instruction from the arithmetic processing unit 107 or the control unit 97, the air supply source 95 is driven, air corresponding to the driving amount is blown out from the pulse air nozzle 108, and the recycled resin 103a is blown out. By blowing off the air from the pulse air nozzle 108, the resin is forced to fall off the locus of free fall, and the recycled resin 103 a is stored in the recycling box 109. A recycling resin 103a is stored in the recycling box 109. On the other hand, the determination object 103 determined not to be recycled resin (hereinafter referred to as “non-recycled resin 103 b”) is stored in the non-recycle box 110 without being blown off by the pulse air nozzle 108. The non-recycle box 110 is disposed adjacent to the recycle box 109. In this case, the non-recycle box 110 is disposed below the end portion of the conveyor belt 101 and at a position where the non-recycle resin 103b freely falls. The position information of the determination object 103 is specified by a position calculation unit 94 connected to the control unit 97. Specifically, on the conveyor belt 101 of the object 103 to be determined from the value from the encoder detector 91 attached to the drive motor 90 of the conveyor belt 101 controlled by the control unit 97 and the scan position of the detection unit 106. Is determined by the position calculation unit 94. Thus, only the recycled resin 103a can be selected from the plurality of determination objects 103.

Next, the detection unit 106 will be described with reference to FIG. FIG. 2 is a diagram showing the detection unit 106 from the X-axis direction of FIG. The detection unit 106 includes a thickness measurement unit 106a and an absorption spectrum calculation unit 106b. The thickness measuring unit 106 a measures the thickness of the determination target object 103. The absorption spectrum calculation unit 106 b calculates an absorption spectrum as a feature amount of the infrared reflected light 105 reflected by the determination target object 103.

First, the operation of measuring the thickness of the determination target object 103 by the detection unit 106 will be described.

In order for the thickness measurement unit 106a to measure the thickness of the object to be determined 103, the detection unit 106 irradiates the reference unit 112 and the object to be determined 103 with measurement light from the light source 111 for thickness measurement, and reflects from the light. By interfering with the received light, a function as an optical interferometer for measuring the thickness of the determination target object 103 is provided. Here, a Michelson interferometer configuration is used as the optical interferometer.

As the thickness measurement light source 111, for example, a wavelength scanning optical coherence tomography device (hereinafter referred to as “SS-OCT”) is used. Here, since a silicon avalanche photodiode is used for the light receiving element 113 that receives light, light having a wavelength of 780 to 860 nm (wavelength of 780 nm or more and 860 nm or less) with which the light receiving element 113 is sensitive is measured by the light source 111 for thickness measurement. Adopt for light. Note that the wavelength of the measurement light may be any wavelength other than the wavelength 1360 to 2500 nm irradiated by the infrared light source 104 shown in FIG. 1 in order to distinguish it from the infrared reflected light 105 reflected by the determination target 103 from the infrared light source 104. . However, the thickness may not be accurately measured with visible light (light with a wavelength of 380 or more and less than 780 nm) or light with a short wavelength (light with a wavelength of less than 380 nm). For these reasons, it is preferable to use light having a wavelength of 780 or more and less than 1360 nm as measurement light from the light source 111.

The measurement light emitted from the light source 111 for thickness measurement passes through the narrow band filter 114 and is divided into two lights described later by the beam splitter 115. The narrow band filter 114 transmits light having a wavelength of 780 to 860 nm.

Of the light split by the beam splitter 115, the light L <b> 1 (hereinafter referred to as “object light”) L <b> 1 irradiated to the object 103 or the conveyor belt 101 is reflected by the polygon mirror 116. The object light L1 reflected by the polygon mirror 116 is irradiated to the determination target object 103 through the telecentric fθ lens 117 and the wavelength filter 132. The polygon mirror 116 enables scanning in the width direction (Y-axis direction) of the conveyor belt 101 by rotating itself. This scan enables detection of the object light L1 reflected from each scan point on the conveyor belt 101 (position where the object light L1 is irradiated).

The telecentric fθ lens 117 has an fθ function that equalizes the difference in scanning speed between the center and the periphery of the polygon mirror 116. In this case, a telecentric optical system is established between the telecentric fθ lens 117 and the conveyor belt 101.

In order to correct the difference in the optical path length of the object light L1 depending on the angle incident on the telecentric fθ lens 117 by the rotation of the polygon mirror 116, the telecentric fθ lens 117 is thinned from the center to both ends on the conveyor belt 101 side. A glass body (not shown) is installed. The glass body is based on the refractive index of the glass body so that the object light L1 reflected by the polygon mirror 116 is irradiated on the conveyor belt 101 with the same optical path length no matter what angle the light enters the telecentric fθ lens 117. The shape is designed. Instead of the glass body, the wavelength filter 132 may be configured so that the thickness thereof decreases from the center to both ends.

The object light L1 irradiated from the beam splitter 115 through the polygon mirror 116, the telecentric fθ lens 117, and the wavelength filter 132 to the object to be determined 103 is reflected on the surface of the object to be determined 103, and travels backward on the same path. It enters the beam splitter 115 again.

Of the light split by the beam splitter 115, light different from the object light L <b> 1 (hereinafter referred to as “reference light”) L <b> 2 enters the reference unit 112 via the narrowband filter 118 and the condenser lens 119. . The narrow band filter 118 transmits light having a wavelength of 780 to 860 nm.

The reference unit 112 reflects the incident reference light L <b> 2 inside and then emits it again from the reference unit 112. Details of the reference unit 112 will be described later.

The object light L1 reflected from the surface of the determination object 103 and the reference light L2 emitted from the reference unit 112 are again incident on the beam splitter 115, and are combined into one light beam (that is, interference light). L3).

The interference light L3 is emitted from the beam splitter 115, reflected and diffracted by the diffraction grating 122, and dispersed at different angles for each wavelength.

The split interference light L3 is incident on the light receiving surface of the light receiving element 113 via the interference light condensing lens 123 and the narrow band filter 124. The narrow band filter 124 transmits light having a wavelength of 780 to 860 nm.

The light receiving element 113 has a plurality of light receiving surfaces, and the interference light L3 dispersed by wavelength by the diffraction grating 122 is incident on each light receiving surface. The light receiving element 113 photoelectrically converts the interference light L3 incident on each light receiving surface into a current. The analog data converted into current is converted into digital data by the optical gain current-voltage conversion amplifier 125 and the high-speed AD conversion circuit 126. The converted digital data is sent to the thickness measuring unit 106a. At this time, the thickness of the determination target object 103 is measured by the thickness measurement unit 106a based on the wavelength of the light whose intensity is increased by the interference. In the following description, the measured thickness of the determination target object 103 is referred to as “measured thickness”. Information on the measured thickness measured by the thickness measuring unit 106 a is sent to the arithmetic processing unit 107.

The narrow-band filters 114, 118, and 124 are installed to prevent light having a wavelength of 1360 to 2500 nm used for calculating an absorption spectrum from being incident as noise on light having a wavelength of 780 to 860 nm used for thickness measurement. Yes.

Next, an operation for calculating the absorption spectrum of the infrared reflected light 105 reflected by the determination target object 103 using the detection unit 106 will be described.

The infrared reflected light 105 reflected by the determination target object 103 enters the beam splitter 115 through the same path as the object light L1.

The infrared reflected light 105 incident on the beam splitter 115 enters the diffraction grating 122 through the same path as the interference light L3. The diffraction grating 122 reflects and diffracts the incident interference light L3 and the infrared reflected light 105 at different angles for each wavelength. At this time, the light having a wavelength of 780 to 860 nm, which is the interference light L3, enters the interference light condensing lens 123, and the light having the wavelength of 1360 to 2500 nm, which is the infrared reflected light 105, enters the condensing lens 127 for the infrared light. As shown, a diffraction grating 122, a condensing lens for interference light 123, and a condensing lens for infrared light 127 are arranged.

The infrared reflected light 105 incident on the infrared light condenser lens 127 passes through the infrared light narrowband filter 128 and enters the light receiving surface of the infrared light receiving unit 129. The infrared narrowband filter 128 transmits light having a wavelength of 1360 to 2500 nm.

The infrared light receiving unit 129 has a plurality of light receiving surfaces, and the infrared reflected light 105 that is spectrally separated by the diffraction grating 122 for each wavelength is incident on each light receiving surface. The infrared light receiving unit 129 photoelectrically converts the received infrared reflected light 105 into a current. The analog data converted into current is converted into digital data by the optical gain current-voltage conversion amplifier 130 and the high-speed AD conversion circuit 131. The converted digital data is sent to the absorption spectrum calculation unit 106b. At this time, the light intensity varies depending on the wavelength due to the light absorption phenomenon of the determination target object 103. Therefore, the absorption spectrum calculation unit 106b obtains the intensity distribution of the infrared reflected light 105 for each wavelength of the determination target object 103, and calculates the absorption spectrum. Information on the absorption spectrum calculated by the absorption spectrum calculation unit 106 b is sent to the arithmetic processing unit 107.

The wavelength filter 132 is disposed between the conveyor belt 101 and the telecentric fθ lens 117, and shields light having a wavelength of less than 780 nm. This is because light having a wavelength other than 780 to 2500 nm used for thickness measurement or absorption spectrum calculation becomes noise. However, light exceeding a wavelength of 2500 nm has a large transmission loss in a general optical system made of resin or glass and is naturally filtered. Therefore, it is sufficient to shield light having a wavelength of less than 780 nm.

Next, a specific method for determining whether the determination target object 103 is a recycled resin will be described.

FIG. 3 shows, as an example, the measurement result of the absorption spectrum of the transparent PS object 103 having a thickness of 1 mm, 2 mm, and 3 mm. In FIG. 3, the vertical axis represents absorbance and the horizontal axis represents wavelength (μm). These absorption spectra are calculated by an absorption spectrum calculation unit 106b provided in the detection unit 106 shown in FIG. The absorption spectrum of the non-transparent PS object 103 is shown as a reference absorption spectrum (referred to as “reference” in FIG. 3). From FIG. 3, it can be seen that the transparent PS determination object 103 and the non-transparent PS determination object 103 show different absorption spectra. It can also be seen that the transparent PS has an absorption spectrum that changes depending on the thickness of the determination target object 103. The reference absorption spectrum is constant regardless of the thickness of the resin. The reference absorption spectrum is an absorption spectrum of a resin that does not transmit white light, and specifically means an absorbance obtained with a white resin with respect to a standard diffusion plate.

When the object 103 shown in FIG. 1 is irradiated with the infrared light 105A from the infrared light source 104, the infrared reflected light 105 reflected by the object 103 is conveyed below the object 103. Infrared reflected light 105C reflected by the path (conveyor belt 101) overlaps. Therefore, when the infrared reflected light 105 reflected by the determination target 103 is received, the infrared reflected light 105C reflected from the conveyance path (conveyor belt 101) is also received.

At this time, the inventors have found that the influence of the infrared reflected light 105 </ b> C reflected from the conveyor belt 101 changes depending on the thickness of the determination target object 103. This can be understood from the results of FIG. That is, as a result of experiments by the inventors, it has become clear that the absorption spectrum of a transparent recycled resin changes depending on its thickness.

Therefore, as will be described in detail later, with respect to a plurality of transparent recycled resins that differ only in thickness conditions, absorption spectra corresponding to each thickness are stored as reference data in the storage unit 107a of the arithmetic processing unit 107 in FIG. 4A described later. Prepare in advance. Next, of the prepared reference data, the reference data of the recycled resin having a thickness corresponding to the measured thickness of the determination target object 103 is selected by the determination unit 107b of the arithmetic processing unit 107 described later. Hereinafter, the selected reference data is referred to as “selection reference data”. Next, by comparing the selection reference data with the absorption spectrum of the determination target 103, the determination unit 107b can determine whether the determination target 103 is a recycled resin.

The processing method of determination by the arithmetic processing unit 107 will be described. FIG. 4A shows a block diagram of the detection unit 106 and the arithmetic processing unit 107.

The arithmetic processing unit 107 includes a storage unit 107a and a determination unit 107b.

The storage unit 107a stores in advance a plurality of types of absorption spectra for each thickness of the transparent recycled resin as reference data. In this case, the storage unit 107a also has a function as a reference data acquisition unit that acquires reference data.

Based on the measured thickness and absorption spectrum of the determination target 103 and a plurality of reference data stored in the storage unit 107a, the determination unit 107b determines whether the determination target 103 is a recycled resin. Do. The measured thickness and absorption spectrum of the determination object 103 are respectively calculated by the thickness measurement unit 106a and the absorption spectrum calculation unit 106b provided in the detection unit 106, and input to the determination unit 107b.

The method of the determination process by the determination unit 107b will be described with reference to FIGS. 2 and 4A and the flowchart shown in FIG.

First, reference data (selection reference data) for a recycled resin having a thickness equal to the measured thickness of the determination target object 103 input from the detection unit 106 is determined from a plurality of reference data stored in the storage unit 107a. The selection is made by the unit 107b (step S1). When there is no selection reference data having a thickness equal to the measured thickness of the object 103 to be determined, an allowable range is determined in advance, and thickness selection reference data that falls within the allowable range with respect to the measured thickness of the object 103 to be determined. You may make it select as selection reference data in the recycled resin of the thickness corresponding to the measured thickness of the to-be-determined object 103. FIG. This will be described later.

Next, the determination unit 107b compares the absorption spectrum of the determination target 103 input from the detection unit 106 with the selection reference data, and the determination unit 107b determines the absorption spectrum of the determination target 103 (step S2). ). At this time, after the gain of the input absorption spectrum is adjusted by the determination unit 107b, spectrum leveling is performed by the determination unit 107b.

Finally, based on the comparison in step S2, the determination unit 107b determines whether the determination object 103 is a recycled resin (step S3). As an example of the determination method in step S3, the determination unit 107b uses a chemometric technique that extracts necessary information from the feature amount of the absorption spectrum. The chemometrics method is a method for estimating an effective result by an optimal processing method using a mathematical method or a statistical method from calculated multivariate data and multivariate data. As another method, a linear multiple regression analysis method, a principal component analysis method, a PLS (Partial Last Squires) regression analysis method, or the like may be used in the determination unit 107b. Further, cluster analysis may be used, and among them, the Mahalanobis distance or the asymmetric Mahalanobis distance may be used in the determination unit 107b.

As described above, it is determined by the recycled resin determination device 100 whether or not the determination target object 103 is recycled resin.

Incidentally, in step S1, a case is described in which the reference data for the recycled resin having the same thickness as the measured thickness is selected as the selection reference data from among a plurality of reference data stored in the storage unit 107a. The determination object 103 constituting the mixed plastic includes the determination objects 103 having various thicknesses. That is, in order to select reference data having a thickness equal to the measured thickness, a huge amount of reference data must be stored in the storage unit 107a in advance. If the amount of reference data to be handled becomes enormous, a burden is imposed on the determination unit 107b that selects specific reference data from among them. For this reason, the processing speed of the determination unit 107b may be reduced.

Therefore, the inventors may select the selection criterion data by the determination unit 107b so that the difference between the thickness corresponding to the selection criterion data and the measured thickness of the determination target object 103 is 0.5 mm or less. Was found from the experimental results. By doing so, it is possible to determine the recycled resin in the determination unit 107b without causing a decrease in determination accuracy without using the selection reference data in the recycled resin having a thickness matching the measured thickness in the determination unit 107b. The inventors have found. This will be described based on experimental data.

From FIG. 3, in the absorption spectrum of transparent PS, noise corresponding to each thickness is on the reference absorption spectrum. That is, the reference data is data including a reference absorption spectrum and noise corresponding to the thickness. Here, the noise refers to an absorption spectrum caused by reflected light (infrared reflected light 105) from the conveyance path (conveyor belt 101).

Since the standard absorption spectrum is constant regardless of the thickness of the resin, the noise changes due to the thickness. That is, if noise corresponding to the thickness of the resin is subtracted from the absorption spectrum of the resin whose thickness has been calculated, determination based only on the reference absorption spectrum that does not depend on the thickness becomes possible.

Therefore, FIG. 6 shows an absorption spectrum obtained by subtracting noise corresponding to PS having a thickness of 2 mm and 3 mm from an absorption spectrum calculated for PS having a thickness of 1 mm, and a reference absorption spectrum of PS, respectively. In FIG. 6, the vertical axis represents absorbance and the horizontal axis represents wavelength (μm). As a feature quantity of an absorption spectrum of PS, it is known that a peak is shown in a wavelength band of 1.763 μm. The P1 region in FIG. 6 is where the peak of the PS absorption spectrum appears. In the P1 region, the absorption spectrum obtained by subtracting noise corresponding to PS having a thickness of 2 mm or 3 mm has a variation from the reference absorption spectrum, and therefore, the recycled resin cannot be accurately determined. From this, it can be understood that when there is a difference of 1 mm or more between the measured thickness of the determination target object 103 and the thickness corresponding to the noise included in the selection reference data, the determination cannot be performed with high accuracy.

Next, FIG. 7 shows an absorption spectrum obtained by subtracting noise corresponding to PS having a thickness of 1 mm from the absorption spectrum calculated for PS having a thickness of 1.5 mm, and a reference absorption spectrum of PS, respectively. In FIG. 7, the vertical axis represents absorbance and the horizontal axis represents wavelength (μm). The P2 region in FIG. 7 is where the peak of the PS absorption spectrum appears. As described above, when correction is performed using noise having a difference of 0.5 mm with respect to the measured thickness of the determination target object 103 (noise corresponding to PS having a thickness of 1 mm), a peak indicating a feature amount should be confirmed. Can be determined with high accuracy.

As a result of conducting an experiment as shown in the example above, the inventors used the reference data in the recycled resin having a thickness within 0.5 mm as a difference from the measured thickness of the determination target object 103 as the selection reference data. The inventors have found that it is possible to determine whether the object 103 is a recycled resin.

That is, it can be understood that the storage unit 107a in FIG. 4A may store reference data for recycled resin having a thickness of 1 mm. This is because the maximum difference between the thickness of the selection reference data and the measured thickness is 0.5 mm. Thereby, it is possible to reduce the amount of reference data to be stored in advance in the storage unit 107a. In addition, by providing an allowable range of 0.5 mm for the difference between the thickness of the selection reference data and the measured thickness in this way, the determination unit 107b also reduces the amount of reference data to be selected, so that it can process at high speed. Can be done.

Furthermore, the present inventors have found that the order of measuring the thickness of the object 103 to be determined may be 1 mm intervals. This is because if the thickness (measurement thickness) of the object to be determined 103 is measured at intervals of 1 mm, the difference between the measured thickness and the actual thickness of the object to be determined 103 is 0.5 mm or less. In this case, the reference data for the recycled resin having a thickness corresponding to the measurement interval may be stored in the storage unit 107a.

A reference unit 112 shown in FIG. 2 will be described as means for measuring the measured thickness of the determination target object 103 at intervals of 1 mm.

The reference unit 112 includes a fiber type optical demultiplexer 120 and a reflection mirror group 121. The fiber type optical demultiplexer 120 demultiplexes the incident reference light L2 for each wavelength. The reflection mirror group 121 includes a plurality of mirrors 121a to 121e that reflect the reference light L2 demultiplexed by the fiber-type optical demultiplexer 120 so as to have different optical path lengths. Since the wavelength of the light included in the reference light L2 is set to 780 to 860 nm, here, the reference light L2 is converted into light having wavelengths of 780 nm, 800 nm, 820 nm, 840 nm, and 860 nm, respectively. Spectroscopy. In this case, the mirrors 121a to 121e constituting the reflecting mirror group 121 are arranged so as to give different optical path length differences for each wavelength at intervals of 1 mm. Specifically, the mirror 121a that reflects light having a wavelength of 780 nm is arranged so that the optical path length of light having a wavelength of 780 nm included in the reference light L2 is 1 mm shorter than the optical path length of object light L1 reflected by the conveyor belt 101. Has been placed. In addition, a mirror 121b that reflects light having a wavelength of 800 nm is disposed so that the optical path length of light having a wavelength of 800 nm included in the reference light L2 is 2 mm shorter than the optical path length of object light L1 reflected from the conveyor belt 101. Yes. Similarly, the mirror 121c that reflects light with a wavelength of 820 nm, the mirror 121d that reflects light with a wavelength of 840 nm, and the mirror 121e that reflects light with a wavelength of 860 nm have an optical path length difference between the object light L1 and the reference light L2. Are arranged to be 3 mm, 4 mm, and 5 mm, respectively. Thereby, when the reference light L2 and the object light L1 are caused to interfere, the optical path length of the object light L1 can be measured by detecting the strengthened wavelength.

Since the object light L1 is reflected by the surface of the determination object 103 on the conveyor belt 101, for example, when light with a wavelength of 780 nm is strengthened by interference, the surface of the determination object 103 is positioned 1 mm from the conveyor belt 101. You can see that it is at (height). Since the determination object 103 is crushed into small pieces as a mixed plastic, the position (height) of the surface of the determination object 103 from the conveyor belt 101 can be regarded as the thickness of the determination object 103. Therefore, the thickness of the determination target object 103 can be measured by measuring the optical path length of the object light L1.

When the thickness of the object 103 to be determined is 1.2 mm, the reference light L2 having a wavelength corresponding to the thickness of 1 mm (780 nm) and the reference light L2 having a wavelength corresponding to the thickness of 2 mm (800 nm) interfere with the object light L1. Arise. In this case, interference by the reference light L2 having a wavelength (780 nm) corresponding to the thickness of 1 mm is stronger than interference by the reference light L2 having a wavelength (800 nm) corresponding to the thickness of 2 mm. ) Is measured as 1 mm. At this time, determination is performed using the reference data (selection reference data) for the recycled resin having a thickness of 1 mm with respect to the determination target object 103 having a measured thickness of 1.0 mm and an actual thickness of 1.2 mm.

Thus, if the measured thickness is measured at intervals of 1 mm, the difference from the actual thickness is 0.5 mm or less, so it is possible to use reference data prepared at intervals of 1 mm. Thereby, the number of reference data to be prepared in advance can be reduced. Furthermore, since the thickness is measured at intervals of 1 mm, the load on the arithmetic processing unit 107 can be reduced. In this case, it is necessary to prepare reference data in which the thickness interval to be measured is matched with the corresponding thickness.

In the first embodiment, as an example, the determination target 103 having a thickness of about 0.3 to 5.5 mm is assumed. Therefore, the number of mirrors in the reflection mirror group 121 in the reference unit 112 is five, and preparation is performed. The reference data to be used are also five types corresponding to thicknesses from 1 mm to 1 mm at intervals of 1 mm. If the thickness variation of the determination target 103 changes, the number of mirrors may be set to 6 or more and 4 or less, and the type or number of reference data may be changed. Furthermore, the wavelength of the measurement light emitted from the light source 111 may be changed in a range of 780 or more and less than 1360 nm.

Further, in order to cause interference in the reference light L2 having an optical path length of 1 mm intervals, the coherence distance of the light source 111 is set to 1 mm or more. Furthermore, it is desirable that the coherence distance is less than 2 mm so that the reference light L2 having three or more types of wavelengths does not interfere simultaneously.

It should be noted that the thickness of the determination object 103 can be measured with an accuracy of 0.1 mm or less from the ratio of the intensity of the interference light of each wavelength. For example, in the object 103 having a thickness of 1.2 mm and the object 103 having a thickness of 1.3 mm, the interference intensity of the reference light L2 having a wavelength corresponding to 1 mm (780 nm) and a wavelength corresponding to 2 mm (800 nm) ) Is different from the interference intensity of the reference light L2. Therefore, by measuring the difference in interference intensity in advance, the measurement thickness can be measured with an accuracy of 0.1 mm or less.

Here, although the case where the determination target 103 is PS has been described, the same result can be obtained even when the determination target 103 is other resin such as PP or ABS. Regardless of the type of resin, the determination object 103 can be accurately determined by subtracting the correction data corresponding to the thickness (noise corresponding to the thickness) from the calculated absorption spectrum. However, if correction data corresponding to each type of resin is used, it is possible to determine the resin with higher accuracy. This is because if the thickness of the resin is increased, the resin is affected by absorption by the resin itself, and the correction data corresponding to the thickness may be different for each type of resin due to this. When the thickness is smaller than 0.5 mm, the absorption spectrum (conveyance path absorption spectrum) of the conveyance path (conveyor belt 101) may be used as the correction data.

However, since the reference absorption spectrum is different for each type of resin, it is necessary to prepare or acquire a different reference absorption spectrum for each type of resin in the storage unit 107a. Therefore, it is preferable to store different reference data for each type of resin in the storage unit 107a. This is because the reference data includes a reference absorption spectrum and noise (correction data) corresponding to the thickness.

When the determination unit 107b determines the determination target 103 using the absorption spectrum of the determination target 103 and the selection reference data, the absorption spectrum of the determination target 103 obtained by subtracting noise, the reference absorption spectrum, and the like. The determination object 103 may be determined based on the above. Further, the determination of the determination target object 103 may be performed based on the reference absorption spectrum added with noise and the absorption spectrum of the determination target object 103. Further, a plurality of types of reference absorption spectra to which noise has been added are prepared in advance as reference data for each thickness, and based on the selection reference data selected from the reference data and the absorption spectrum of the determination target 103, the determination target 103 The determination may be made.

Next, the flow of the resin discrimination method by the recycled resin determination device 100 shown in FIG. 1 will be described with reference to FIG.

First, by the operation of the hopper 102, the determination object 103 arranged on the upper part is dropped to an arbitrary place in the input area 93A on the conveyor belt 101 (step S21).

Next, since the conveyor belt 101 is always in operation, the object 103 is conveyed to the detection area 93B below the detection unit 106 by the flow. The measured thickness and the absorption spectrum are measured by the thickness measuring unit 106a and the absorption spectrum calculating unit 106b of the detection unit 106 for the determination target 103 carried to the detection region 93B (step S22). .

Next, the determination unit 107b determines whether the determination target 103 is a recycled resin based on the measured thickness of the determination target 103 and the absorption spectrum. The determination means is as shown in the flow of FIG. 5 (step S23).

Next, to-be-determined object 103 (recycled resin 103a) determined to be recycled resin is blown out by pulse air nozzle 108 under the control of control unit 97 and stored in recycling box 109 (step S24).

The to-be-determined object 103 (non-recycled resin 103 b) determined not to be recycled resin is not blown out by the pulse air nozzle 108 under the control of the control unit 97, and the non-recycled box 110 is caused by free fall from the conveyor belt 101. (Step S25).

As described above, it is possible to determine the recycled resin 103a from the determination object 103 by the determination unit 107b and to select only the determined recycled resin 103a by the pulse air nozzle 108.

In addition, if a plurality of lines of pulse air nozzles 108 as a sorting unit or a sorting mechanism are arranged and a recycle box 109 corresponding to each is prepared, sorting such as PP and PS can be performed.

Although the thickness measurement unit 106a and the absorption spectrum calculation unit 106b provided in the detection unit 106 are operated in synchronization with an external clock, basically, the measurement thickness data and the absorption spectrum data are measured at the same measurement point. Are calculated at once.

Here, a resin having a total light transmittance of 70% or more is described as a transparent resin.

As shown in FIG. 4B, as another example of the reference data acquisition unit, reference data may be acquired as necessary from a reference data acquisition unit 107c provided separately from the storage unit 107a. Further, the reference data may be acquired by the reference data acquisition unit 107c as needed from the external database 107e via the communication line 107d.

In addition, if there are a plurality of pulse air nozzles 108 in the width direction of the conveyor belt 101, a plurality of determination objects 103 are provided even if a plurality of determination objects 103 are placed on the conveyor belt 101 in the width direction of the conveyor belt 101. Can be individually determined.
<First Modification>
FIG. 9 shows a reference unit 133 that is a modification of the reference unit 112 of the first embodiment.

In the reference unit 112 shown in FIG. 2, the size of the fiber-type optical demultiplexer 120 is a problem, and it is difficult to reduce the size. Therefore, in the reference unit 133 of the first modified example in FIG. 9, the diffraction grating 134 is used instead of the fiber type optical demultiplexer 120 to reduce the size. The reference unit 133 includes a diffraction grating 134, a condensing lens group 135 composed of a plurality (five in FIG. 9) of condensing lenses, and a reflection composed of a plurality of (five in FIG. 9) reflecting mirrors. And a mirror group 136.

The reference light L2 incident on the reference unit 133 is split by the diffraction grating 134 into wavelengths of 780 nm, 800 nm, 820 nm, 840 nm, and 860 nm. The split reference light L2 is reflected by the respective reflecting mirrors of the reflecting mirror group 136 through the respective condensing lenses of the condensing lens group 135. The reference light L2 reflected by the respective reflecting mirrors of the reflecting mirror group 136 is emitted from the reference unit 133 via the respective condensing lenses of the condensing lens group 135 so as to travel backward in the optical path. In this case, the diffraction grating 134, the condenser lens group 135, and the reflection mirror group 136 are arranged so that different optical path lengths are given to the reference light L2 of each wavelength at intervals of 1 mm.

Thereby, the reference unit 133 of the first modification can achieve the same effect as the reference unit 112 while reducing the size of the apparatus.

Heretofore, the thickness measuring unit 106a in FIG. 2 has been described as measuring the measured thickness using an optical interferometer (optical interferometry) that uses measurement light different from the infrared light 105. On the other hand, the thickness measuring unit 106a may measure the measured thickness using a triangulation instrument (triangulation method). However, since the order of the measured thickness to be obtained can be easily controlled as described above when the optical interferometer is used, it is desirable that the thickness measuring unit 106a measures the measured thickness with the optical interferometer.

(Second Embodiment)
A manufacturing apparatus 141 for recycled resin recycled products according to the second embodiment will be described with reference to FIG. 10A. The recycled resin recycled product manufacturing apparatus 141 includes the recycled resin determination apparatus 100 according to the first embodiment and a recycled resin molding apparatus 142. The recycled resin recycled product manufacturing apparatus 141 is the recycled resin recycled product manufacturing apparatus 141 using the determination target article 103 (recycled resin 103a) determined as the recycled resin by the recycled resin determining apparatus 100 according to the first embodiment. Manufactures recycled plastic products. As such a recycled resin molding apparatus 142, a molding apparatus capable of performing the steps described in JP-A-2001-205632 can be used. Therefore, as a method for manufacturing a recycled resin recycled product according to the first embodiment, the determination step of determining whether or not the determination target object 103 is the recycled resin by the recycled resin determination device 100 according to the first embodiment, A manufacturing step of manufacturing a recycled resin recycled product using the recycled resin recycled product manufacturing apparatus 141 using the determination target product 103 (recycled resin 103a) determined to be recycled resin in the step. Has been.

In this molding apparatus, first, a mixed raw material 82 in which metal powder is mixed with a pulverized product of resin waste (recycled resin 103a in FIG. 1) determined as a recycled resin is formed into a concave portion of a lower mold 83 as shown in FIG. 10B. Put in 83b. Then, the pulverized product 81 obtained by pulverizing only the resin waste as shown in FIG. 10C is put on the mixed raw material 82. Thereafter, as shown in FIG. 10D, the upper mold 83 a is lowered and pressure-molded with the lower mold 83. Then, by opening the upper mold 83a and the lower mold 83 and taking out from the lower mold 83, a recycled molded product 84 (recycled resin recycled product) as shown in FIG. 10E can be manufactured. The regenerated molded product 84 thus obtained has a two-layer structure in which the surface layer 84a and the backing layer 84b are integrated. Since the surface layer 84a is formed of the mixed raw material 82 of the pulverized resin waste and the metal powder, the surface finish is metallic. For this reason, a high-class feeling can be improved. Such a recycled molded product 84 can be applied to various products such as a decorative panel used as a building material as a recycled resin recycled product.

The recycled resin recycled product manufacturing apparatus 141 according to the second embodiment is recycled using the to-be-determined product 103 (recycled resin 103a) determined as the recycled resin by the recycled resin determining apparatus 100 according to the first embodiment. The manufacturing method of the recycled resin recycled product which manufactures a resin recycled product can be implemented. For this reason, it is possible to save resources.

In addition, this invention is not limited to the said embodiment or modification, It can implement in another various aspect. In addition, by appropriately combining any of the various embodiments or modifications, it is possible to achieve the respective effects.

According to the apparatus for determining recycled resin according to the present invention, a desired recycled resin can be determined from a crushed mixed plastic for recycling from waste home appliances and the like. Moreover, according to the recycled resin recycled product manufacturing apparatus according to the present invention, it is possible to manufacture a recycled resin recycled product by using a determination target determined as a resin to be recycled.

Although the present invention has been fully described in connection with embodiments with reference to the accompanying drawings, various changes or modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included therein unless they depart from the scope of the invention as defined by the appended claims.

Claims (9)

A transport device for transporting an object to be determined, which is a transparent resin;
An infrared light source for irradiating the determination object with infrared light;
An infrared light receiving unit that receives infrared reflected light from the object to be determined irradiated with the infrared light; and
An absorption spectrum calculation unit for calculating an absorption spectrum of the object to be determined from the infrared reflected light received by the infrared light receiving unit;
A thickness measuring unit for measuring a measurement thickness which is a thickness of the object to be determined;
A storage unit that stores in advance reference data for different recycled resins for each thickness;
Among the reference data, the reference data for the recycled resin having a thickness corresponding to the measured thickness measured by the thickness measurement unit is selected as selection reference data, and the selection reference data and the absorption spectrum calculation unit are calculated. And a determination unit that determines whether the determination target is the recycled resin based on the absorption spectrum. The determination unit has a thickness at which a difference from the measurement thickness is 0.5 mm or less based on the measurement thickness measured by the thickness measurement unit among the reference data acquired by the reference data acquisition unit. The reference data of the recycled resin is selected as the selection reference data, and it is determined whether the determination object is the recycled resin based on the selection reference data and the absorption spectrum. Judgment device. 3. The recycled resin determination apparatus according to claim 1 or 2, wherein the thickness measurement unit measures the measurement thickness by an optical interferometer using measurement light having a wavelength different from that of the infrared light. The infrared light source irradiates infrared light having a wavelength of 1360 nm to 2500 nm,
The recycling apparatus according to claim 3, wherein the optical interferometer uses measurement light having a wavelength of 780 nm or more and less than 1360 nm. 3. The recycled resin determination apparatus according to claim 1, wherein the reference data includes an absorption spectrum of the recycled resin. It is determined whether the determination object is the recycled resin by the recycled resin determination device according to claim 1 or 2,
A method for manufacturing a recycled resin recycled product, wherein a recycled resin recycled product is manufactured using the determination target determined as the recycled resin. It is determined whether or not the determination object is the recycled resin by the determination apparatus for the recycled resin according to claim 3,
A method for manufacturing a recycled resin recycled product, wherein a recycled resin recycled product is manufactured using the determination target determined as the recycled resin. It is determined whether or not the determination object is the recycled resin by the recycled resin determination device according to claim 4,
A method for manufacturing a recycled resin recycled product, wherein a recycled resin recycled product is manufactured using the determination target determined as the recycled resin. It is determined whether or not the object to be determined is the recycled resin by the recycled resin determination device according to claim 5,
A method for manufacturing a recycled resin recycled product, wherein a recycled resin recycled product is manufactured using the determination target determined as the recycled resin.

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