Detection method and detection device

Abstract

The present invention provides a detection method and a detection device which can effectively detect pellets containing minute amounts of carbon black. This detection method is for distinguishing a pellet containing 5-80,000 mass ppm of carbon black from a mixture of pellets containing a black colorant, said detection method comprising: a step for supplying, to an optically non-transparent conveyance section having an L value of not less than 85, the mixture of pellets such that pellets do not overlap; a step for irradiating, with infrared light having a wavelength of 800-1,000 nm, the pellets supplied to the optically non-transparent conveyance section; a step for using a camera to image the pellets irradiated with the infrared light; and a step for detecting, from the captured image, a pellet containing 5-1,000 mass ppm of carbon black.

Description

Detection method and detection device

[0001] The present invention relates to a detection method and a detection device. In particular, the present invention relates to a detection method for discriminating pellets containing carbon black.

[0002] Conventionally, pellet inspection and detection have been performed by photographing pellets moving on a transport unit with a camera provided in the transport unit, and analyzing the obtained image data. As such pellet inspection and detection methods, those described in Patent Documents 1 to 3 are known.

[0003] Japanese Unexamined Patent Publication No. 2001-27610, Japanese Unexamined Patent Publication No. 8-136467, Japanese Unexamined Patent Publication No. 2012-242340

[0004] As described above, although pellet detection methods have been studied, there is still room for improvement. The present invention is intended to solve such a problem, and an object of the present invention is to provide a detection method and a detection device that can effectively detect pellets containing a trace amount of carbon black.

[0005] Based on the above problems, the inventors conducted research and found that by making the pellet transport section white and irradiating it with infrared light, pellets containing trace amounts of carbon black can be effectively detected. Specifically, the above problems were solved by the following means: [1] A detection method for distinguishing pellets containing 5 to 80,000 ppm by mass of carbon black from a mixture of pellets containing a black coloring agent, comprising the steps of: supplying the mixture of pellets to a non-light-transmitting transport section with an L value of 85 or more so that the pellets do not overlap; irradiating the pellets supplied to the non-light-transmitting transport section with infrared light having a wavelength of 800 nm to 1000 nm; imaging the pellets irradiated with infrared light using a camera; and detecting pellets containing 5 to 80,000 ppm by mass of carbon black from the image captured. [2] The detection method according to [1], wherein the non-light-transmitting transport section is white. [3] The detection method according to [1] or [2], wherein the pellets are thermoplastic resin pellets. [4] The detection method according to any one of [1] to [3], wherein the pellet comprises at least one of polyamide resin, polyacetal resin, and modified polyphenylene ether resin. [5] The detection method according to any one of [1] to [4], wherein the non-light-transmitting transport section is white, and the pellet comprises at least one of polyamide resin, polyacetal resin, and modified polyphenylene ether resin. [6] A detection device for distinguishing pellets containing 5 to 80,000 ppm by mass of carbon black from a mixture of pellets containing a black coloring agent, the device comprising a transport section for transporting pellets, an infrared irradiation element for irradiating pellets on the transport section, and a camera for imaging pellets irradiated with infrared light, wherein the surface on which the pellets are supplied to the transport section is a non-light-transmitting surface with an L value of 85 or more. [7] The detection device according to [6] for performing the detection method according to any one of [1] to [5].

[0006] The present invention provides a detection method and apparatus for effectively detecting pellets containing trace amounts of carbon black.

[0007] This is a schematic diagram showing an example of a pellet detection device according to this embodiment.

[0008] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "these embodiments") will be described in detail. These embodiments are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments. In this specification, "~" is used to mean that the numerical values ​​before and after it include the lower and upper limits. Furthermore, the upper and lower limits of numerical values ​​in this specification are given as examples of these embodiments, regardless of the combination of the upper and lower limits. In this specification, preferred combinations of embodiments are more preferred embodiments. In this specification, all physical properties and characteristic values ​​are given at 23°C unless otherwise specified.

[0009] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended function is achieved. In this specification, ppm means mass ppm. If the measurement methods etc. described in the standards shown in this specification differ from year to year, unless otherwise specified, the standards as of January 1, 2025 shall apply. If the measurement methods etc. described in the standards shown in this specification are obsolete as of January 1, 2025, the standards in effect at the time of obsolete shall apply. Figure 1 may not be consistent with reality in terms of scale, etc.

[0010] In this specification, "pellets containing 5 to 80,000 ppm by mass of carbon black" may be referred to as "pellets containing trace amounts of carbon black." Also, "pellets that do not contain carbon black but contain a black coloring agent, and / or pellets containing less than 5 ppm by mass of carbon black and a black coloring agent" may be referred to as "black pellets."

[0011] The detection method of this embodiment is a detection method for identifying pellets containing 5 to 80,000 ppm by mass of carbon black from a mixture of pellets containing a black coloring agent, and comprises the steps of: supplying the mixture of pellets to a non-light-transmitting transport unit with an L value of 85 or more so that the pellets do not overlap; irradiating the pellets supplied to the non-light-transmitting transport unit with infrared light having a wavelength of 800 nm to 1000 nm; imaging the pellets irradiated with infrared light using a camera; and detecting pellets containing 5 to 80,000 ppm by mass of carbon black from the image captured. With this configuration, it becomes possible to effectively detect pellets containing 5 to 80,000 ppm by mass of carbon black (pellets containing trace amounts of carbon black) from a mixture of pellets containing a black coloring agent.

[0012] In this embodiment, a mixture of pellets containing a black coloring agent is supplied to a white-toned transport section so that the pellets do not overlap, and infrared light is irradiated to effectively detect pellets containing trace amounts of carbon black from the mixture of pellets containing a black coloring agent. In other words, when there is a mixture of pellets containing trace amounts of carbon black and black pellets, all the pellets appear dark to the naked eye, making identification difficult.

[0013] In contrast, in this embodiment, since the substrate of the transport section is white, when infrared light is irradiated, the white portion reflects the light. As a result, black pellets appear white, and pellets containing trace amounts of carbon black appear black, making detection by image analysis easier and enabling effective detection of pellets containing trace amounts of carbon black.

[0014] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is merely one example of an embodiment of the present invention and is not limited to these.

[0015] Figure 1 is a schematic diagram showing the flow of the detection method of this embodiment, where 1 is a transport unit, 2 is an infrared irradiation element, 3 is a camera for imaging the irradiated infrared pellets, 4 is a pellet supply unit, and 5 is a device for homogenizing the pellets. In this embodiment, the transport unit 11 in the part of the transport unit 1 where the pellets are supplied has an L value of 85 or higher and is made of non-light-transmitting material. Therefore, pellets containing trace amounts of carbon black appear black when illuminated by infrared light supplied from the infrared irradiation element 2, and black pellets reflect white light. In this embodiment, by imaging the pellets irradiated with the infrared light using the camera 3, it becomes possible to accurately distinguish pellets containing trace amounts of carbon black from the pellet mixture.

[0016] In other words, two methods for detecting pellets are known: transmitted light inspection and reflected light inspection. The transmitted light inspection method involves using a transparent material for the pellet transport section, irradiating light from the side of the transport section furthest from the pellets (usually the bottom), and taking a photograph with a camera from the side of the transport section closest to the pellets (usually the top). The inventors' research revealed that the transmitted light inspection method could not distinguish pellets containing trace amounts of carbon black. Therefore, the inventors decided to adopt the reflected light inspection method.

[0017] The pellet detection method of the present invention will now be described in more detail. The detection method of this embodiment includes a step of supplying a mixture of pellets containing a black coloring agent to a non-light-transmitting transport section with an L value of 85 or higher, such that the pellets do not overlap. By supplying the mixture of pellets containing a black coloring agent to a white transport section in such a way that the pellets do not overlap, it becomes possible to more effectively distinguish pellets containing trace amounts of carbon black when irradiated with infrared light. Examples of methods to prevent the pellets from overlapping include vibrating the pellets to make them uniform, and adjusting the pellet supply section so that the pellets come out one row at a time.

[0018] In this embodiment, the transport unit is made of a non-light-transmitting material with an L value of 85 or higher. The L value is preferably 90 or higher, but may be 100 or lower. The transport unit is preferably white. Non-light-transmitting means that the infrared transmittance is preferably less than 1%, and may be less than 0.1%.

[0019] The detection method of this embodiment includes the step of irradiating the pellets supplied to the non-light-transmitting transport section with infrared light having a wavelength of 800 nm to 1000 nm. When infrared light is irradiated, the light is reflected in the white transport section. Therefore, black pellets appear white, and pellets containing trace amounts of carbon black appear black.

[0020] The detection method of this embodiment includes the step of imaging a pellet irradiated with infrared light using a camera. A high-sensitivity CMOS camera is an example of the camera.

[0021] The detection method of this embodiment includes a step of detecting pellets containing trace amounts of carbon black from the captured image. Examples of methods for detecting pellets containing trace amounts of carbon black from the captured image include visual inspection and software analysis.

[0022] The pellet mixture in this embodiment is a mixture of resin pellets, specifically pellets containing a trace amount of carbon black and black-colored pellets (pellets that do not contain carbon black but contain a black-coloring agent, and / or pellets containing less than 5 ppm by mass of carbon black and a black-coloring agent). The mass ratio of pellets containing a trace amount of carbon black to black-colored pellets is preferably such that the proportion of pellets containing a trace amount of carbon black is 1 or more, preferably 9,000 or less, and more preferably 1,000 or less per 10,000 pellets in the pellet mixture. The pellet mixture may contain only one type of pellet containing a trace amount of carbon black and one type of black-colored pellet, or it may contain two or more types. If it contains two or more types, it is preferable that the total amount is within the above range. Furthermore, the mixture may also contain pellets that do not contain a black-coloring agent. An example of such a mixture is recycled pellets.

[0023] In this embodiment, the size of the pellets (pellets containing trace amounts of carbon black and / or black pellets) is preferably such that the number average of the longest parts of the pellets is 2.5 mm or more, more preferably 2.75 mm or more, even more preferably 2.9 mm or more, and depending on the application, it may be 8.5 mm or more, 8.75 mm or more, or 8.9 mm or more, and also preferably 9.5 mm or less, more preferably 9.25 mm or less, even more preferably 9.1 mm or less, and depending on the application, it may be 3.5 mm or less, 3.25 mm or less, or 3.1 mm or less.

[0024] The pellets in this embodiment (pellets containing trace amounts of carbon black and / or black pellets) may be thermoplastic resin pellets or thermosetting resin pellets, but thermoplastic resin pellets are preferred. Thermoplastic resin pellets mean that the most abundant component among the resin components contained in the pellet is thermoplastic resin, and it is preferable that 50% by mass or more of the pellet is composed of thermoplastic resin. The pellets in this embodiment preferably contain at least one of polyamide resin, polyacetal resin, and modified polyphenylene ether resin, and polyamide resin is more preferable. The type of polyamide resin is not particularly specified, and it may be an aliphatic polyamide resin or a semi-aromatic polyamide resin, but semi-aromatic polyamide resin is more preferable.

[0025] Examples of aliphatic polyamide resins include polyamide 4, polyamide 46, polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 11, and polyamide 12, with polyamide 6, polyamide 66, and polyamide 666 being preferred, and polyamide 66 being more preferred. As described above, the polyamide resin used in this embodiment preferably includes a semi-aromatic polyamide resin. Here, a semi-aromatic polyamide resin is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 20 to 80 mol% (preferably 30 to 80 mol%, more preferably 40 to 70 mol%) of the total structural units of the diamine-derived structural units and dicarboxylic acid-derived structural units contain aromatic rings.

[0026] Examples of semi-aromatic polyamide resins include terephthalic acid-based polyamide resins (polyamide 6T, polyamide 9T, polyamide 10T), and xylylenediamine-based polyamide resins (polyamide MXD6, polyamide MXD10, polyamide MP6, polyamide MP10, etc.) which contain diamine-derived structural units and dicarboxylic acid-derived structural units, with 70 mol% or more of the diamine-derived structural units being derived from xylylenediamine.

[0027] The diamine-derived structural units of the xylylenediamine-based polyamide resin are more preferably derived from xylylenediamine (preferably para-xylylenediamine and / or meta-xylylenediamine) in an amount of 75 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly most preferably 99 mol% or more.

[0028] The xylylenediamine is preferably para-xylylenediamine and / or meta-xylylenediamine. The xylylenediamine preferably contains 0 to 100 mol% meta-xylylenediamine and 100 to 0 mol% para-xylylenediamine (provided that the total of meta-xylylenediamine and para-xylylenediamine does not exceed 100 mol%), more preferably 10 to 100 mol% meta-xylylenediamine and 90 to 0 mol% para-xylylenediamine, even more preferably 20 to 100 mol% meta-xylylenediamine and 80 to 0 mol% para-xylylenediamine, even more preferably 40 to 100 mol% meta-xylylenediamine and 60 to 0 mol% para-xylylenediamine, and even more preferably 60 to 100 mol% meta-xylylenediamine and 40 to 0 mol% para-xylylenediamine. In xylylenediamine-based polyamide resins, it is preferable that the total of constituent units derived from para-xylylenediamine and meta-xylylenediamine constitutes 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, even more preferably 98 mol% or more, and even more preferably 99 mol% or more of the constituent units derived from diamine. The upper limit of the total of the constituent units derived from para-xylylenediamine and meta-xylylenediamine is 100 mol%.

[0029] Diamines other than meta-xylylenediamine and para-xylylenediamine that can be used as raw material diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine, as well as 1,3-bis( Examples include alicyclic diamines such as aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane, as well as aromatic ring-containing diamines such as bis(4-aminophenyl) ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. One or more of these can be used in combination.

[0030] On the other hand, of the xylylenediamine-based polyamide resin, the dicarboxylic acid-derived constituent units are preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and especially most preferably 99 mol% or more, which are preferably derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms (preferably sebacic acid).

[0031] Preferred α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms for use as raw material dicarboxylic acid components in xylylenediamine-based polyamide resins include, for example, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, undecanediic acid, and 1,12-dodecanediic acid. One or more of these can be used in combination, but among these, at least one of adipic acid, sebacic acid, and 1,12-dodecanediic acid is preferred, adipic acid and / or sebacic acid is more preferred, and sebacic acid is even more preferred, as these allow the melting point of the polyamide resin to be within a suitable range for molding.

[0032] Examples of dicarboxylic acid components other than those mentioned above include phthalate compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, which can be used individually or in mixtures of two or more.

[0033] It should be noted that while xylylenediamine-based polyamide resins are mainly composed of diamine-derived and dicarboxylic acid-derived structural units, they do not completely exclude other structural units, and may also contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, "main component" refers to the structural unit in the xylylenediamine-based polyamide resin in which the total number of diamine-derived and dicarboxylic acid-derived structural units is the largest among all structural units. In this embodiment, it is preferable that the total of diamine-derived and dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin accounts for 90% by mass or more of the total structural units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0034] It is also preferable to use polyamide resins manufactured using biomass raw materials (biomass polyamide resins) for xylylenediamine-based polyamide resins. By using biomass polyamide resins, the environmental impact can be reduced. In xylylenediamine-based polyamide resins, bio-adipic acid can be used as the biomass raw material. In addition, adipic acid certified by Mass Balance Certification (ISCC PLUS) can also be used. Mass balance certification means that the extent to which renewable raw materials and bio-raw materials are used in each factory or production facility, and how much of the product is produced or shipped, is quantified and guaranteed along with the quality.

[0035] The thermoplastic resin used in this embodiment may be recycled thermoplastic resin (including recovered products, material recycled products, chemical recycled products, etc.), rejected products, or scraps generated when molding molded products from resin compositions or pellets.

[0036] In this embodiment, the pellets (pellets containing trace amounts of carbon black and / or black pellets) typically contain resin in a proportion of 50 to 99.999% by mass of the pellet, preferably 60 to 99.999% by mass, and more preferably 70 to 99.999% by mass.

[0037] The pellets in this embodiment (pellets containing trace amounts of carbon black and / or black pellets) may contain fillers. Examples of fillers include glass fibers, flake glass, mica, etc., with glass fibers being preferred. The proportion of fillers in the pellets of this embodiment is preferably 25% by mass or more, preferably 70% by mass or less, and may be 50% by mass or less.

[0038] The pellets in this embodiment (pellets containing trace amounts of carbon black and / or black pellets) may contain, in addition to the resin and filler, other components such as release agents, nucleating agents, flame retardants, flame retardant additives, light stabilizers, heat stabilizers (antioxidants), ultraviolet absorbers, fluorescent whitening agents, anti-dripping agents, antistatic agents, anti-fogging agents, anti-blocking agents, flow modifiers, plasticizers, dispersants, antibacterial agents, alkalis, hydrolysis resistance modifiers, matting agents, plasticizers, dispersants, antistatic agents, color inhibitors, and gelling inhibitors. Details of these can be found in paragraphs 0130 to 0155 of Japanese Patent No. 4894982, and these contents are incorporated herein. Furthermore, the pellets in this embodiment may contain additives described in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, without departing from the spirit of the present invention, and these contents are incorporated herein. The content of the other components is 0% by mass or more, preferably less than 10% by mass, more preferably less than 7% by mass, even more preferably less than 5% by mass, even more preferably less than 3% by mass, and may be less than 1% by mass, based on 100% by mass of the pellets (pellets containing trace amounts of carbon black and / or black pellets).

[0039] The composition of pellets containing trace amounts of carbon black and black pellets preferably share a composition of 80% or more by mass of components other than carbon black, more preferably 90% or more by mass, even more preferably 95% or more by mass, and may share 100% by mass.

[0040] In this embodiment, the amount of carbon black in the pellet containing a trace amount of carbon black is 5 ppm by mass or more, and preferably 6 ppm by mass or more. There is no upper limit, but in order to make effective use of the detection method of this embodiment, it is preferable that the concentration is one that cannot be distinguished by visual inspection. For example, it is 80,000 ppm by mass or less, more preferably 50,000 ppm by mass or less, even more preferably 10,000 ppm by mass or less, even more preferably 5,000 ppm by mass or less, even more preferably 1,000 ppm by mass or less, and furthermore, it may be 800 ppm by mass or less, 600 ppm by mass or less, 400 ppm by mass or less, 200 ppm by mass or less, or 170 ppm by mass or less.

[0041] The pellets containing trace amounts of carbon black in this embodiment tend to have relatively low infrared transmittance. Specifically, it is preferable that the transmittance of infrared rays at the irradiated wavelength is less than 60%. Furthermore, the lower limit of the infrared transmittance is 0% or more, but may be 10% or more. The infrared transmittance here is measured according to the description in the examples described later.

[0042] On the other hand, the amount of carbon black in the black pellets in this embodiment is less than 5 ppm by mass, preferably 3 ppm by mass or less, more preferably 2 ppm by mass or less, even more preferably 1 ppm by mass or less, and also 0 parts by mass or more.

[0043] The black pellets in the present embodiment contain a black colorant. The black colorant in the present embodiment does not include carbon black. Examples of the black colorant include, in addition to black colorants, black-tone pigments obtained by combining two or more chromatic colorants. That is, the purpose is to include those that are not completely black but appear substantially black to the human eye. The black colorant may be a dye or a pigment, and is preferably a dye. The content of the black colorant is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, further preferably 0.1 mass% or more, still more preferably 0.2 mass% or more, and is preferably 5 mass% or less, more preferably 3 mass% or less, and may be 1 mass% or less, based on 100 mass% of the black pellets.

[0044] The black pellets in the present embodiment preferably have infrared transmittance. Specifically, the transmittance of infrared rays at the irradiation wavelength is preferably 50% or more. The upper limit of the infrared transmittance is 100% or less, and may be 80% or less, 70% or less, or 60% or less. The infrared transmittance herein is measured according to the description in the Examples described later.

[0045] The detection apparatus of the present embodiment includes a transport unit that transports pellets, an infrared irradiation element for irradiating the pellets on the transport unit, and a camera for capturing an image of the irradiated pellets, wherein the surface of the transport unit to which the pellets are supplied is a non-light-transmissive surface with an L value of 85 or more, and the detection apparatus discriminates pellets containing 5 to 80000 mass ppm of carbon black from a mixture of pellets containing a black colorant. An example of the detection apparatus of the present embodiment is shown in the above-mentioned Figure 1. Further, the detection apparatus of the present embodiment is preferably used for carrying out the detection method of the present embodiment.

[0046] Hereinafter, the present invention will be described in more detail with reference to Examples. The materials, usage amounts, ratios, treatment contents, treatment procedures, and the like shown in the following Examples can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments and the like used in the Examples are difficult to obtain due to discontinuation or the like, measurement can be performed using other instruments having equivalent performance.

[0047] 1. Raw Materials The raw materials shown in Table 1 were used.

[0048] <Synthesis Example 1 Synthesis of MP10 (M / P molar ratio = 7:3)> After heating and dissolving sebacic acid in a reactor under a nitrogen atmosphere, while stirring the contents, a mixed diamine of para-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company, Inc.) and meta-xylylenediamine (manufactured by Mitsubishi Gas Chemical Company, Inc.) at a molar ratio of 3:7 was gradually added dropwise under pressurization (0.35 MPa) so that the molar ratio of the diamines to sebacic acid was about 1:1, and the temperature was raised to 235°C. After completion of the dropwise addition, the reaction was continued for 60 minutes to adjust the amount of components having a molecular weight of 1,000 or less. After the reaction was completed, the content was taken out in a strand form and pelletized with a pelletizer to obtain a polyamide resin (MP10).

[0049] 2-1. Preparation of Pellets 1 to 4 and Pellet 8 The components shown in Table 1 were adjusted to have the compositions shown in Table 2 or Table 3 (each component in Table 2 or Table 3 is expressed in parts by mass). The components other than glass fiber were each weighed and dry-blended, and then fed from the screw root of a twin-screw extruder (manufactured by Shibaura Machine Co., Ltd., TEM26SS) using a twin-screw cassette weighing feeder (manufactured by Kubota Corporation, CE-W-1-MP). For the glass fiber, a vibrating cassette weighing feeder (manufactured by Kubota Corporation, CE-V-1B-MP) was used to feed the glass fiber into the aforementioned twin-screw extruder from the side of the extruder, and the mixture was melt-kneaded with the resin component and the like to obtain resin composition pellets. The set temperature of the extruder was 280°C. The pellets were produced by strand cutting, and adjusted so that the average value of the longest portion was 3.00 mm.

[0050] 2-2. Preparation of Pellets 5 to 7 As shown in Table 3, Pellets 1 to 4 and 8 were dry-blended.

[0051] <Light Transmittance> The pellets obtained above were dried at 120°C for 4 hours, and then 1.5 mm thick test specimens were prepared using an injection molding machine (Sumitomo Heavy Industries, Ltd., SE-50D). During molding, the cylinder temperature was 280°C and the mold surface temperature was 110°C. For the test specimens (1.5 mm thick) obtained above, the light transmittance (unit: %) at a wavelength of 980 nm was measured according to ISO 13468-2. For the measurement, the transmittance was measured on the gate side of the test specimen using a transmittance measuring instrument. The transmittance measuring instrument used was a TMG3 manufactured by LPKF Laser & Electronics SE.

[0052] <Color difference> For the 1.5 mm thick test specimen obtained above, the color difference (ΔE ＊ The light was measured using the reflectivity method (using a C / 2 light source with a white board). A SE6000 manufactured by Nippon Denshoku Industries Co., Ltd. was used for the measurement.

[0053]

[0054] In Tables 2 and 3, CBMB represents the carbon black masterbatch content, while CB content represents the carbon black content itself.

[0055] 3. Examples 1-5, Comparative Examples 1 and 2 <Discrimination Comparison on Infrared Camera> Pellets were blended as shown in Table 4. Each component in Table 4 represents the number of pellets. That is, Example 1 is a blend of 10 pellets (1) and 90 pellets (8). ＊ The pellets were spread out on a sheet with a value of 98, ensuring they did not overlap, and infrared light with a wavelength of 980 nm was shone perpendicularly to the sheet. While the sheet was illuminated with infrared light, the images captured by the camera (details below) were visually observed to determine whether or not 10 pellets could be identified. The judgment was made by five experts and decided by majority vote.

[0056] Infrared illumination was performed using the HLDL3-300X28IR-DF-W manufactured by CCS Corporation. <<Camera used for shooting>> Basler ACA1920-155μm Camera lens: Fujifilm Corporation HF16XA-5M

[0057] <Visual Comparison> The same procedure was followed as in the <Infrared Camera Comparison> above, except that infrared light was not used.

[0058]

[0059] As is clear from the above results, pellets containing trace amounts of carbon black could not be visually confirmed, but they could be identified by irradiating them with infrared light on a non-light-transmitting transport section with an L value of 85 or higher (Examples 1-5). On the other hand, pellets with a carbon black content of less than 5 ppm by mass could not be detected by the method of the present invention (Comparative Examples 1 and 2).

[0060] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

[0061] 1. Conveying unit 2. Infrared irradiation element 3. Camera 4. Supply unit 5. Homogenization device

Claims

1. A detection method for identifying pellets containing 5 to 80,000 ppm by mass of carbon black from a mixture of pellets containing a black coloring agent, comprising: a step of supplying the mixture of pellets to a non-light-transmitting transport unit with an L value of 85 or more so that the pellets do not overlap; a step of irradiating the pellets supplied to the non-light-transmitting transport unit with infrared light having a wavelength of 800 nm to 1000 nm; a step of imaging the pellets irradiated with infrared light using a camera; and a step of detecting pellets containing 5 to 80,000 ppm by mass of carbon black from the image captured.

2. The detection method according to claim 1, wherein the non-light-transmitting transport section is white.

3. The detection method according to claim 1, wherein the pellet is a thermoplastic resin pellet.

4. The detection method according to claim 1, wherein the pellet comprises at least one of a polyamide resin, a polyacetal resin, and a modified polyphenylene ether resin.

5. The detection method according to claim 1, wherein the non-light-transmitting transport section is white, and the pellets contain at least one of polyamide resin, polyacetal resin, and modified polyphenylene ether resin.

6. A detection device for distinguishing pellets containing 5 to 80,000 ppm by mass of carbon black from a mixture of pellets containing a black coloring agent, wherein the surface on which the pellets are supplied to the transport unit is a non-light-transmitting surface with an L value of 85 or higher.

7. A detection device according to claim 6 for performing the detection method according to any one of claims 1 to 5.

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