Device, system, method, or program for determining policy of reuse or horizontal recycling of used fiber-reinforced plastic, or horizontal recycling method

Abstract

The present invention determines a policy of reuse or horizontal recycling of used fiber-reinforced plastic without measuring mechanical properties of the used fiber-reinforced plastic. Provided is a device for reuse or horizontal recycling according to non-destructive inspection information of used fiber-reinforced plastic. The device infers mechanical physical property information from the non-destructive inspection information of the used fiber-reinforced plastic input from an input unit, determines horizontal recycling, or a policy of reuse or horizontal recycling of the fiber-reinforced plastic on the basis of the mechanical property information, and outputs information on the horizontal recycling, or the policy of reuse or horizontal recycling.

Description

Apparatus, system, method or program for determining reuse or horizontal recycling measures for used fiber reinforced plastics, and horizontal recycling method

[0001] The present invention relates to an apparatus, system, method, or program for determining a reuse or horizontal recycling strategy for used fiber-reinforced plastics, or a horizontal recycling method.

[0002] Molded articles reinforced with reinforcing fibers can reinforce the brittleness of the matrix resin with high-strength fibers. For this reason, they are widely used as lightweight materials with excellent mechanical properties. Conventionally, non-destructive testing is performed in the production process of fiber-reinforced plastics to detect defective products during manufacturing. For example, Patent Document 1 discloses an inspection device for estimating the mechanical properties of fiber-reinforced plastics, which learns information about known fiber-reinforced plastics and estimates the mechanical properties from non-destructive testing information about a second fiber-reinforced plastic.

[0003] On the other hand, since used waste resins are often used for long periods under harsh environmental conditions, efforts are being made to increase the recycling rate of waste materials and expand the range of reuse applications by reformulating them according to the properties of the waste materials. For example, Patent Document 2 describes an invention in which, in order to evaluate the physical properties and lifespan of waste materials and realize appropriate reuse applications, thermoplastic resin waste is collected, crushed, washed, re-pelletized, and other processes are performed, and the physical properties and lifespan are evaluated after heat melt molding, and a recycling policy is determined. Furthermore, Patent Document 3 discloses an invention providing a recycling system that enables high-quality recyclability, consisting of processes such as product evaluation, dismantling, parts sorting, recycling, and manufacturing of recycled parts. This enables the acquisition of high-quality recycled materials and effective transportation management.

[0004] Patent Documents 4 and 5 describe food inspection systems that perform learning of a neural network from photographed images of food to determine whether the food is of good quality.

[0005] International Publication No. 2022 / 009596 Japanese Patent Application Publication No. 2002-292629 Japanese Patent Application Publication No. 07-024437 International Publication No. 2019 / 151393 International Publication No. 2019 / 151394

[0006] However, the mechanical property prediction device described in Patent Document 1 does not consider recycling or reuse at all. The waste material recycling method described in Patent Document 2 cannot evaluate the lifespan without decomposing or destroying the resin. Furthermore, because the waste material is shredded or crushed, the inherent mechanical properties of the waste material are significantly reduced after recycling. The recycling method described in Patent Document 3 recycles the plastic parts of the used product based on the degree of deterioration corresponding to the displayed information, and it is unclear how much of the used plastic parts actually remain. Therefore, an optimal recycling or reuse method cannot be provided.

[0007] Therefore, an object of the present invention is to provide a method for determining a reuse or horizontal recycling strategy for used fiber-reinforced plastics without measuring the mechanical properties of the used fiber-reinforced plastics, and for horizontal recycling without deteriorating the mechanical properties of the used fiber-reinforced plastics, thereby enabling more effective use of used fiber-reinforced plastics.

[0008] The above object can be achieved by the following aspects: [1] An apparatus for determining a reuse or horizontal recycling measure in accordance with non-destructive testing information for used fiber-reinforced plastics, comprising: an input unit for inputting the non-destructive testing information for the used fiber-reinforced plastics; a memory unit storing a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information for known fiber-reinforced plastics as training data to learn an association between the non-destructive testing information and the mechanical property information and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program that determines a reuse or horizontal recycling measure for the fiber-reinforced plastics based on the mechanical property information; a processor that executes the mechanical property estimation program to estimate the mechanical property information for the used fiber-reinforced plastics from the non-destructive testing information for the used fiber-reinforced plastics, and that executes the policy determination program to determine a reuse or horizontal recycling measure for the used fiber-reinforced plastics from the estimated mechanical property information; and an output unit that outputs information on the reuse or horizontal recycling measure for the used fiber-reinforced plastics.[2] A system for determining a reuse or horizontal recycling measure in accordance with non-destructive testing information of used fiber reinforced plastics, comprising: a server; and a client terminal connected to the server through an information and communication network, wherein the server comprises: a memory unit storing a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information of known fiber reinforced plastics as training data to learn the association between the non-destructive testing information and the mechanical property information and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program that determines a reuse or horizontal recycling measure for the fiber reinforced plastic based on the mechanical property information; a processor that executes the mechanical property estimation program and the policy determination program; and a server-side communication interface that inputs non-destructive testing information of the used fiber reinforced plastics received from the client terminal through the information and communication network to the processor, and transmits information on a reuse or horizontal recycling measure for the used fiber reinforced plastic estimated by the mechanical property estimation program and the policy determination program from the received non-destructive testing information to the client terminal through the information and communication network, wherein the client terminal A system comprising: an input unit for inputting non-destructive testing information for used fiber reinforced plastics; a client-side communication interface for transmitting the non-destructive testing information to the server through the information and communication network and receiving from the server information on reuse or horizontal recycling measures for the used fiber reinforced plastics inferred from the non-destructive testing information; and an output unit for outputting the information on reuse or horizontal recycling measures for the used fiber reinforced plastics received from the server through the information and communication network.[3] A method for determining a strategy for reuse or horizontal recycling of used fiber-reinforced plastics, the method comprising the steps of: acquiring non-destructive testing information of the used fiber-reinforced plastic; estimating the mechanical property information of the used fiber-reinforced plastic from the non-destructive testing information of the used fiber-reinforced plastic using a prediction model trained by machine learning using the mechanical property information and non-destructive testing information of a fiber-reinforced plastic sample, the mechanical property information and non-destructive testing information of which are known, as training data; determining a strategy for reuse or horizontal recycling of the used fiber-reinforced plastic based on the estimated mechanical property information; and outputting information on the determined strategy for reuse or horizontal recycling. [4] A horizontal recycling method for recycling used fiber-reinforced plastics determined to be subject to horizontal recycling by the method described in [3] by remolding, wherein the fiber-reinforced plastic contains reinforcing fibers and a thermoplastic resin, and the molding method for remolding is press molding. [5] The horizontal recycling method for used fiber-reinforced plastics according to [4], wherein the used fiber-reinforced plastic is a press-molded product. [6] The method for horizontally recycling used fiber-reinforced plastics according to [4] or [5], wherein the horizontal recycling does not include a step of isolating reinforcing fibers from the fiber-reinforced plastic. [7] The method for horizontally recycling used fiber-reinforced plastics according to any of [4] to [6], wherein the used fiber-reinforced plastic contains discontinuous reinforcing fibers, and the relationship between the weight-average fiber length Lw1 of the reinforcing fibers contained in the used fiber-reinforced plastic and the weight-average fiber length Lw2 of the reinforcing fibers contained in the fiber-reinforced plastic after horizontal recycling of the used fiber-reinforced plastic satisfies 2 mm≦Lw2≦Lw1. [8] The method for horizontally recycling used fiber-reinforced plastics according to [7], wherein the weight-average fiber length Lw1 of the reinforcing fibers contained in the used fiber-reinforced plastic is 3 mm or more.[9] The reinforcing fibers contained in the used fiber reinforced plastic are such that, when the fiber length of the reinforcing fiber bundle is Li, the single fiber diameter of the reinforcing fiber constituting the reinforcing fiber bundle is Di, and the number of single fibers contained in the reinforcing fiber bundle is Ni, Li is 1 mm or more and 100 mm or less, and Li / (Ni × Di. ２ ) is 8.0 x 10 １ 3.3 x 10 ３The method for horizontally recycling used fiber-reinforced plastics according to any one of [7] or [8], which contains the following reinforcing fiber bundles:

[10] The method for horizontally recycling used fiber-reinforced plastics according to any one of [4] to [9], wherein the used fiber-reinforced plastics have been used in automobile parts, and the fiber-reinforced plastics after horizontal recycling of the used fiber-reinforced plastics are reused as automobile parts.

[11] The method for horizontally recycling used fiber-reinforced plastics according to any one of [4] to

[10] , wherein the non-destructive inspection information is a vibration inspection image, an acoustic characteristic image, a temperature distribution image, or numerical data on natural frequencies.

[12] The method for horizontally recycling used fiber-reinforced plastics according to any one of [4] to

[10] , wherein the mechanical property information is information on the elastic modulus or breaking strength of the used fiber-reinforced plastic.

[13] The method for horizontally recycling used fiber-reinforced plastics according to

[12] , wherein the information on the elastic modulus includes the elastic modulus or a rank when the elastic modulus is ranked, and the information on the breaking strength includes the breaking strength or a rank when the breaking strength is ranked.

[14] The method for horizontally recycling used fiber-reinforced plastics according to

[13] , wherein the information on the elastic modulus or breaking strength includes at least one of: information indicating that the elastic modulus or breaking strength is difficult to estimate; information indicating that the elastic modulus or breaking strength corresponds to used fiber-reinforced plastics that can be reused or horizontally recycled; and information indicating that the elastic modulus or breaking strength corresponds to used fiber-reinforced plastics that cannot be reused or horizontally recycled.

[15] A program for determining a reuse or horizontal recycling measure in accordance with non-destructive testing information of used fiber reinforced plastics, comprising: a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information of known fiber reinforced plastics as training data to learn the association between the non-destructive testing information and the mechanical property information, and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program for determining a reuse or horizontal recycling measure for the fiber reinforced plastic based on the mechanical property information, wherein the program causes a processor to execute the mechanical property estimation program to estimate the mechanical property information of the used fiber reinforced plastic from the non-destructive testing information of the used fiber reinforced plastic, and to execute the policy determination program to determine a reuse or horizontal recycling measure for the used fiber reinforced plastic from the estimated mechanical property information.

[0009] According to the present invention, it is possible to estimate the mechanical properties of used fiber-reinforced plastics solely from non-destructive testing information without measuring the mechanical properties of the fiber-reinforced plastics, and this can be useful in determining measures for reuse or horizontal recycling of used fiber-reinforced plastics. By instantaneously estimating with high accuracy mechanical property information that cannot be estimated from non-destructive testing information no matter how hard a person tries, it is possible to reduce waste when reproducing products using used fiber-reinforced plastics and provide high-quality recycled products at low cost.

[0010] FIG. 1 is a schematic diagram showing the configuration of an apparatus 1 that determines a reuse or horizontal recycling strategy according to non-destructive testing information of used fiber reinforced plastic. FIG. 2 is a schematic diagram showing the configuration of a system 100 that determines a reuse or horizontal recycling strategy according to non-destructive testing information of used fiber reinforced plastic. FIG. 3 is a wavelet image of a defect-free fiber reinforced plastic. FIG. 4 is a wavelet image of a defect-free fiber reinforced plastic. FIG. 5 is a wavelet image of a defective fiber reinforced plastic. FIG. 6 is a temperature distribution image (active thermography image) of a fiber reinforced plastic that includes "voids".

[0011] Hereinafter, an embodiment of the present invention will be described.

[0012] [Overview of the Inspection System] The inspection system of this embodiment uses used fiber-reinforced plastics, whose mechanical properties are unknown, as the object of non-destructive testing, and estimates the mechanical properties from the non-destructive testing information of the used fiber-reinforced plastics without actually measuring them. This makes it possible to grade the used fiber-reinforced plastics according to the mechanical properties, and to determine a reuse or horizontal recycling strategy depending on the grade. Here, used fiber-reinforced plastics conceptually include parts that use fiber-reinforced plastics containing reinforcing fibers, which are collected from the general market, or which are collected from inventory.

[0013] [Nondestructive Inspection Information] In the present invention, nondestructive inspection information refers to information obtained by nondestructively inspecting the internal state of a fiber-reinforced plastic, such as vibration inspection images, acoustic property images, temperature distribution images, and numerical data on natural frequencies. Vibration properties refer to information about the used fiber-reinforced plastic itself, such as displacement, acceleration, and natural frequencies, obtained by vibrating the used fiber-reinforced plastic in a fixed or unfixed state. Vibration property information may be numerical data such as natural frequencies, or vibration inspection images or acoustic property images using wavelet images. Examples of vibration inspection images include the wavelet images shown in Figures 3A to 3D. Here, wavelet images are two-dimensional images obtained by wavelet transforming the vibration of the used fiber-reinforced plastic, with the vibration frequency on the vertical axis, time on the horizontal axis, and vibration amplitude represented by shading. Temperature distribution information refers to information indicating the temperature distribution of the used fiber-reinforced plastic being inspected. For example, images (thermography) of the used fiber-reinforced plastic captured with an infrared camera can be used as temperature distribution information.

[0014] [Mechanical property information] In the present invention, the mechanical property information is information indicating the mechanical properties of the fiber-reinforced plastic, for example, information regarding the fracture or elasticity of the fiber-reinforced plastic, such as its strength. Examples of the mechanical property information include information regarding fracture strength, such as tensile strength or flexural strength, and information regarding elastic modulus, such as elastic modulus related to fracture strength, elastic modulus related to compressive strength, or elastic modulus related to shear strength.

[0015] 1 is a schematic diagram showing the configuration of an apparatus 1 for determining a reuse or horizontal recycling strategy for used fiber-reinforced plastics based on non-destructive testing information according to a first embodiment of the present invention. The apparatus 1 includes a computer 10, an input unit 20, an output unit 30, etc.

[0016] The computer 10 includes a processor 11, a main memory device 12, an auxiliary memory device 13, an input interface 14, an output interface 15, etc. The computer 10 may be a physical computer, or may be realized by a virtual machine (VM), a container, or a combination of these. More specifically, the processor has a structure that is an electric circuit made up of a combination of circuit elements such as semiconductor elements.

[0017] The processor 11 includes one or more processing devices such as a CPU (Central Processing Unit), a GPU, etc. The processor 11 reads programs such as an OS (Operating System) and other applications stored in the auxiliary storage device 13 into the main storage device 12 and executes the programs, thereby causing the computer 10 to perform various processes.

[0018] The main memory device 12 may be, for example, a volatile memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory), or a non-volatile memory such as a NAND flash memory, a magnetoresistive random access memory (MRAM), or a ferroelectric random access memory (FeRAM).

[0019] The auxiliary storage device 13 is a device capable of storing information, such as a hard disk drive or a solid-state drive (SSD). The auxiliary storage device 13 may be a storage device (cloud) of a server on a network. The processor 11 may download a program from the storage device of the server and execute the program. An external input unit 20 is connected to the input interface 14, and a dataset of known non-destructive testing information and mechanical property information of fiber-reinforced plastics and non-destructive testing information of used fiber-reinforced plastics are input from the input unit 20. The input unit 20 may be, for example, a keyboard, a touchpad, an image scanner, a digital camera, a microphone, or the like. Alternatively, the input unit 20 may be a non-destructive testing device such as a radiographic testing device, an ultrasonic flaw detector, an eddy current testing device, a magnetic particle testing device, an acoustic emission device, a penetrant testing device, or an infrared camera. The input information, such as the non-destructive testing information and the mechanical property information, is transmitted to the processor 11. The input interface 14 and the input unit 20 may be connected via an information and communication network such as the Internet.

[0020] A software library for use in machine learning is installed in the auxiliary storage device 13 of the computer 10, and the processor 11 reads the software from the auxiliary storage device 13 into the main storage device 12 and executes it, causing the computer 10 to function as an inference model, and training data is input to the computer 10 from the input interface 14, and a trained inference model (inference unit) can be obtained by performing supervised learning. Examples of software libraries (machine learning libraries) for use in machine learning include scikit-learn, TensorFlow, PyTorch, Keras, and LightGBM.

[0021] In this embodiment, a data set of non-destructive inspection information and mechanical property information of known fiber-reinforced plastics is input as training data into a computer 10 on which a software library for use in machine learning is installed, and supervised learning is performed to obtain a mechanical property prediction program (trained inference model) that has learned the association between the non-destructive inspection information and the mechanical property information. The obtained mechanical property prediction program is stored in the auxiliary storage device 13. The data set of non-destructive inspection information and mechanical property information used as training data may be calculated, for example, from a model of the fiber-reinforced plastic using the finite element method.

[0022] Fiber-reinforced plastics that have fatigued and cracked due to long-term use or that have resin degradation tend to have low tensile modulus and fracture strength. Furthermore, the presence of defects, voids, or foreign matter within the fiber-reinforced plastic also tends to reduce the tensile modulus and fracture strength. In such fiber-reinforced plastics, cracks, resin degradation, defects, voids, and foreign matter affect the vibration characteristics and temperature distribution. A supervised learning process can be performed using a dataset of nondestructive testing information and mechanical property information for such fiber-reinforced plastics as training data to obtain a mechanical property prediction program.

[0023] Nondestructive testing information for fiber-reinforced plastics is typically used to determine whether defects, voids, or foreign matter exist within the fiber-reinforced plastic, and if so, what their extent of presence is. However, even if a fiber-reinforced plastic contains many defects, voids, or foreign matter, its mechanical properties may be good depending on the distribution of the defects, voids, or foreign matter. In such cases, if a used fiber-reinforced plastic is visually inspected and determined to be unsuitable for reuse or horizontal recycling due to the high number of defects, voids, or foreign matter, the used fiber-reinforced plastic that could be reused or horizontally recycled will end up being discarded, thereby reducing the remanufacturing efficiency. On the other hand, the opposite is also possible. In other words, even if a used fiber-reinforced plastic is visually inspected and determined to be suitable for reuse or horizontal recycling due to the low number of defects, voids, or foreign matter, its mechanical properties may be such that it is unsuitable for reuse or horizontal recycling.

[0024] As a result of verification based on the above viewpoints, the inventors found that there is a correlation between nondestructive testing information and mechanical property information of fiber-reinforced plastics. By subjecting a large amount of actual measurement data of nondestructive testing information and mechanical property information to machine learning using a model such as a neural network or a support vector machine, they succeeded in estimating the mechanical property information of used fiber-reinforced plastics with high accuracy from the nondestructive testing information of the used fiber-reinforced plastics. It has not previously been considered possible to obtain mechanical property information from nondestructive testing information using a machine learning model. For this reason, it has not been easy for those skilled in the art to construct a machine learning model that inputs nondestructive testing information and outputs mechanical property information.

[0025] The dataset to be input to the inference model may be subjected to data augmentation in advance. For example, the mean and variance of the parameters of each class may be calculated, and a random value within the range of (mean - variance) to (mean + variance) may be added to the dataset.

[0026] An inference model can be evaluated by cross-validation, which divides a dataset used in supervised learning into training data and test data for evaluation. For example, holdout validation may be performed, in which the dataset is divided into training data and test data, and learning and evaluation are performed. Alternatively, k-fold cross-validation may be performed, in which the dataset is divided into k parts, and k-1 of the parts are used as training data and the remaining part is used as test data, and learning and evaluation are performed k times.

[0027] Furthermore, by having the processor 11 read the above-mentioned mechanical property estimation program from the auxiliary storage device 13 to the main storage device 12 and execute it, the computer 10 can function as a mechanical property estimation device 1 that estimates mechanical property information from non-destructive testing information of fiber-reinforced plastics whose mechanical property information is unknown. In other words, the computer 10 executes the mechanical property estimation program and estimates mechanical property information from non-destructive testing information input from the input interface 14.

[0028] The auxiliary storage device 13 also stores a policy determination program that determines a reuse or horizontal recycling policy for used fiber-reinforced plastics based on the mechanical property information of the used fiber-reinforced plastics. The processor 11 reads the policy determination program from the auxiliary storage device 13 to the main storage device 12 and executes it, thereby determining a reuse or horizontal recycling policy for the used fiber-reinforced plastics whose mechanical property information has been estimated. Examples of the reuse or horizontal recycling policy include whether horizontal recycling is possible, whether reuse is possible, or whether neither horizontal recycling nor reuse is possible (crushing, recycling, or disposal is required). The auxiliary storage device 13 may also store a program that causes the output unit 30 (described later) to assign information about the reuse or horizontal recycling policy determined by the policy determination program to the used fiber-reinforced plastics. In this case, the processor 11 reads the program from the auxiliary storage device 13 to the main storage device 12 and executes it, causing the computer 10 to operate the output unit 30 so that the output unit 30 assigns information about the reuse or horizontal recycling policy to the used fiber-reinforced plastics.

[0029] The processor 11 that executes the policy determination program determines a policy for reuse or horizontal recycling of used fiber reinforced plastics in accordance with the mechanical property information estimated by the mechanical property estimation program. For example, the rank (mechanical property rank) of used fiber reinforced plastics may be associated with the estimated mechanical property information, and a policy for reuse or horizontal recycling of used fiber reinforced plastics may be determined in accordance with the mechanical property rank.

[0030] For example, if the estimated mechanical property information is the tensile modulus of elasticity, if the tensile modulus of elasticity is equal to or greater than a predetermined first threshold (e.g., 30 GPa), the used fiber-reinforced plastic is determined to be reusable and horizontally recyclable (Rank A). If the tensile modulus of elasticity is less than the first threshold but equal to or greater than a second threshold (e.g., 25 GPa) that is lower than the first threshold, the used fiber-reinforced plastic is determined to be unreusable but horizontally recyclable (Rank B). On the other hand, if the modulus of elasticity is less than the second threshold but equal to or greater than a third threshold (e.g., 20 GPa) that is lower than the second threshold, the used fiber-reinforced plastic is determined to be unreusable and horizontally recyclable, but crushable and recyclable (Rank C). On the other hand, if the modulus of elasticity is less than the third threshold, the used fiber-reinforced plastic is determined to be discarded (Rank D).

[0031] It is also possible to simply associate the mechanical property information with the mechanical property rank without associating the mechanical property information with the reuse or horizontal recycling measure.

[0032] Furthermore, when the estimated mechanical property information is breaking strength, if the breaking strength is equal to or greater than a predetermined first threshold (e.g., 90% of the breaking strength of unused fiber-reinforced plastic), the used fiber-reinforced plastic is determined to be reusable and horizontally recyclable (Rank A). If the breaking strength is less than the first threshold but equal to or greater than a second threshold lower than the first threshold (e.g., 70% of the breaking strength of unused fiber-reinforced plastic), the used fiber-reinforced plastic is determined to be unreusable but horizontally recyclable (Rank B). If the breaking strength is less than the second threshold but equal to or greater than a third threshold lower than the second threshold (e.g., 50% of the breaking strength of unused fiber-reinforced plastic), the used fiber-reinforced plastic is determined to be unreusable and horizontally recyclable, but crushable and recyclable (Rank C). On the other hand, if the breaking strength is less than the third threshold, the used fiber-reinforced plastic is determined to be discarded (Rank D). It should be noted that if the mechanical property information cannot be estimated by the mechanical property estimation program, the used fiber-reinforced plastic may be discarded.

[0033] The processor 11 outputs information about the determined reuse or horizontal recycling measure to the output interface 15. An external output unit 30 may be connected to the output interface 15. The output interface 15 and the output unit 30 may be connected via an information and communication network such as the Internet. The output unit 30 is, for example, a display unit such as a liquid crystal display that displays characters and images, a speaker that outputs sound, or a printer that prints characters and images.

[0034] Examples of information on measures for reuse or horizontal recycling include information that both reuse and horizontal recycling are possible (Rank A), reuse is not possible but horizontal recycling is possible (Rank B), neither horizontal recycling nor reuse is possible but crushed recycling is possible (Rank C), recycling is not possible (disposal, Rank D), etc. Methods for outputting information on measures for reuse or horizontal recycling include displaying information such as "Reuse and horizontal recycling are possible", "Horizontal recycling is possible", "Crushed recycling is possible", "Disposal", etc. on the display, or displaying mechanical property ranks A to D corresponding to this information, playing the information as a message from a speaker, printing the information on a printer, etc.

[0035] The output unit 30 may receive the mechanical property information itself or the information on the mechanical property rank from the output interface 15 and output the mechanical property information itself or the information on the mechanical property rank. For example, the output unit 30 may output information such as the estimated elastic modulus or elastic modulus rank, breaking strength or breaking strength rank of the used fiber-reinforced plastic.

[0036] The value of used fiber-reinforced plastics may be evaluated according to the mechanical property rank. This allows the value of used fiber-reinforced plastics to be evaluated appropriately. Furthermore, the output unit 30 may output information such as the material composition of the used fiber-reinforced plastics and the number of times it has been reused or horizontally recycled. Hereinafter, the "information on the reuse or horizontal recycling measures" determined by the measure determination program, the "mechanical property information itself and information on the mechanical property rank" estimated by the mechanical property estimation program, and the "information on the material composition of used fiber-reinforced plastics and the number of times it has been reused or horizontally recycled" are also simply referred to as "used fiber-reinforced plastic information."

[0037] The output unit 30 may impart the used fiber-reinforced plastic information to the used fiber-reinforced plastic. In this case, a program for imparting the used fiber-reinforced plastic information to the used fiber-reinforced plastic is stored in the auxiliary storage device 13, and the processor 11 reads the program from the auxiliary storage device 13 into the main storage device 12 and executes it, causing the computer 10 to operate the output unit 30 so that the output unit 30 imparts the used fiber-reinforced plastic information to the used fiber-reinforced plastic.

[0038] Adding used fiber-reinforced plastic information to used fiber-reinforced plastic includes, for example, attaching a sticker on which the used fiber-reinforced plastic information is printed to the used fiber-reinforced plastic. A sticker on which the used fiber-reinforced plastic information is printed as characters (for example, the letters A to D indicating the above-mentioned ranks) may be attached to the used fiber-reinforced plastic, or a sticker on which a bar code or two-dimensional code (Japanese Patent No. 2938338) indicating the used fiber-reinforced plastic information is printed may be attached to the used fiber-reinforced plastic.

[0039] Adding used fiber-reinforced plastic information to used fiber-reinforced plastic includes adding information indicating the location of the used fiber-reinforced plastic information to the used fiber-reinforced plastic. For example, the used fiber-reinforced plastic information may be stored on a server on the Internet, and a sticker on which characters indicating a URL corresponding to the used fiber-reinforced plastic information or a two-dimensional code corresponding to the URL is printed may be affixed to the used fiber-reinforced plastic.

[0040] Furthermore, assigning used fiber-reinforced plastic information to used fiber-reinforced plastic includes printing or engraving characters indicating the used fiber-reinforced plastic information (for example, the characters A to D indicating the ranks described above), characters indicating the location (URL) of the used fiber-reinforced plastic information, a barcode, or a two-dimensional code on the surface of the used fiber-reinforced plastic. Assigning used fiber-reinforced plastic information to used fiber-reinforced plastic includes recording the used fiber-reinforced plastic information on an RFID tag and attaching the RFID tag to the used fiber-reinforced plastic. By assigning used fiber-reinforced plastic information to used fiber-reinforced plastic in this way, reuse or horizontal recycling, as described below, can be performed based on the information assigned to the used fiber-reinforced plastic, even in locations distant from the device 1.

[0041] [Reuse or horizontal recycling of used fiber-reinforced plastics] Used fiber-reinforced plastics are ranked based on their estimated mechanical properties, and the parts are separated by rank. Low-ranked plastics are crushed and pulverized (rank C) or discarded (rank D). However, the present invention is directed to the reuse or horizontal recycling of used fiber-reinforced plastics that are relatively high-ranked (rank A or rank B, which still retain some mechanical properties). This allows for more optimal recycling.

[0042] [Reuse] Reuse refers to the reuse of used fiber-reinforced plastic products and parts as they are.

[0043] [Horizontal Recycling] In the present invention, horizontal recycling of used fiber-reinforced plastics means not reusing (reusing) the fiber-reinforced plastic as is, but remolding the fiber-reinforced plastic as is to recycle it into new products or parts without degrading its mechanical properties and while maintaining mechanical properties equivalent to those of new products. Here, "remolding as is" refers to molding used fiber-reinforced plastics without the melt-kneading that is involved in the manufacturing process of injection molding materials and extrusion molding materials. In other words, horizontal recycling in the present invention excludes reusing used fiber-reinforced plastics and reusing them by melt-kneading.

[0044] [Crushed and crushed for reuse] Recycling by crushing and crushing for reuse includes the use of materials as injection molding materials, extrusion molding materials, reinforcing materials for building materials, and as an energy source. Compared to crushing and crushing for reuse, horizontal recycling allows materials to be recycled while retaining the same mechanical properties as new materials, eliminating the need to reprocess the waste and saving energy and resources. It also reduces waste dumping in landfills and prevents resource depletion.

[0045] The horizontal recycling method of the present invention preferably does not include a step of isolating reinforcing fibers from fiber-reinforced plastics. For example, Japanese Patent Application Laid-Open No. 2005-336331 describes a method for recycling fiber-reinforced plastics in which the resin is separated to isolate carbon fibers. However, this method requires excessive energy to extract the carbon fibers, making it difficult to reduce the environmental impact. The horizontal recycling method of the present invention recycles the reinforcing fibers without isolating them, allowing for low-energy reproduction.

[0046] [Conditions for Horizontal Recycling] Used fiber-reinforced plastics to be horizontally recycled contain discontinuous reinforcing fibers, and the relationship between the weight-average fiber length Lw1 of the reinforcing fibers contained in the used fiber-reinforced plastic and the weight-average fiber length Lw2 of the reinforcing fibers contained in the fiber-reinforced plastic after horizontal recycling of the used fiber-reinforced plastic preferably satisfies the following: 0.2 mm≦Lw2≦Lw1. This allows the used fiber-reinforced plastic to be recycled into a new fiber-reinforced plastic while maintaining its mechanical properties. 1 mm≦Lw2≦Lw1 is preferred, and 10 mm≦Lw2≦Lw1 is even more preferred. The specific value of the weight-average fiber length Lw1 contained in the fiber-reinforced plastic after horizontal recycling of the used fiber-reinforced plastic is preferably 3 mm or more, more preferably 5 mm or more but less than 100 mm, and even more preferably 10 mm or more but less than 50 mm. Furthermore, the tensile modulus of the fiber-reinforced plastic obtained by horizontally recycling the used fiber-reinforced plastic preferably remains at least 50%, more preferably at least 70%, of the tensile modulus of the used fiber-reinforced plastic. The above range can be satisfied by devising a crushing and pulverizing process for used fiber-reinforced plastics.

[0047] [Automotive Parts] In the horizontal recycling of the present invention, the used fiber-reinforced plastic is preferably used in automotive parts, and the fiber-reinforced plastic after horizontal recycling is preferably reused as an automotive part. In horizontal recycling, parts made of fiber-reinforced plastic (used fiber-reinforced plastic) are removed from discarded automobiles, nondestructively tested, and their reusability is determined using the device 1 of the present invention. These parts can be reused not only for repairs and maintenance but also for sale in the used parts market. Stimulating demand for used parts can reduce the production of new parts and resource consumption. Furthermore, horizontal recycling can contribute to the realization of a circular economy in the automotive industry. Reusing parts can reduce waste disposal costs and environmental impact. Horizontal recycling of automotive parts is an important initiative toward realizing a sustainable automotive industry and contributes to the effective use of resources and environmental protection.

[0048] In the conventional used parts market, it has been difficult to determine the value of a part and set an appropriate price. This is because the extent of use is unknown, and even if the manufacturing date is known, the type of use is unknown. For example, the value of parts from a car stored in a garage or left outside in a field can differ significantly, even if they have the same date of birth. This invention grades used fiber-reinforced plastics using an inspection program, allowing the value of such used fiber-reinforced plastics to be properly assessed and then reused or recycled.

[0049] [Specific example of horizontal recycling: press molding] In a method for horizontal recycling by remolding used fiber-reinforced plastics, the fiber-reinforced plastic contains reinforcing fibers and a thermoplastic resin, and the molding method for remolding is preferably press molding. Press molding is also sometimes called compression molding. More preferably, the used fiber-reinforced plastic is a press-molded product. By reproducing used fiber-reinforced plastics by press molding, it is possible to easily make the reinforcing fibers 0.2 mm≦Lw2≦Lw1.

[0050] [Reheating] When used fiber reinforced plastic containing a thermoplastic resin is remolded, it is preferable to heat it to the softening point of the thermoplastic resin or higher, return the shaped molded product to a flat plate state, and then press mold it.

[0051] [Hot press molding and cold press molding] Press molding can be performed using molding methods such as hot press molding and cold press molding. Used fiber-reinforced plastics can be reheated to form recycled composite materials, which can then be press-molded, allowing the fiber-reinforced plastics that have been used once to be re-formed into various shapes.

[0052] [Cold Press Molding] When press molding a recycled composite material, press molding using a cold press is preferred. In the cold press molding method, for example, the recycled composite material heated to a first predetermined temperature is placed in a mold set to a second predetermined temperature, and then pressurized and cooled. Specifically, if the thermoplastic resin contained in the recycled composite material is crystalline, the first predetermined temperature is equal to or higher than the melting point, and the second predetermined temperature is lower than the melting point. If the thermoplastic resin is amorphous, the first predetermined temperature is equal to or higher than the glass transition temperature, and the second predetermined temperature is lower than the glass transition temperature. That is, the cold press method includes at least the following steps A-1) to A-2).

[0053] Step A-1) A step of heating the thermoplastic resin to above its melting point but below its decomposition temperature if it is crystalline, or above its glass transition temperature but below its decomposition temperature if it is amorphous. Step A-2) A step of placing the recycled composite material heated in step A-1) above in a molding die whose temperature is adjusted to below its melting point if the thermoplastic resin is crystalline, or below its glass transition temperature if it is amorphous, and applying pressure. By performing these steps, the molding of the recycled composite material can be completed.

[0054] The above steps must be performed in the order listed above, but other steps may be included between each step. For example, other steps include a shaping step prior to step A-2) in which a different shaping mold from the mold used in step A-2) is used to pre-shape the material into the shape of the mold cavity. The shape of the recycled composite material may be developed by computer inverse molding analysis from the three-dimensional shape of the press-molded product to be manufactured.

[0055] [Hot Press Molding] In the hot press molding method, for example, a recycled composite material is placed in a mold, pressure is applied while the temperature of the mold is raised to a first predetermined temperature, and the mold is cooled to a second predetermined temperature. Specifically, if the thermoplastic resin constituting the recycled composite material is crystalline, the first predetermined temperature is equal to or higher than the melting point, and the second predetermined temperature is lower than the melting point. If the thermoplastic resin contained in the recycled composite material is amorphous, the first predetermined temperature is equal to or higher than the glass transition temperature, and the second predetermined temperature is lower than the glass transition temperature. Hot press molding preferably includes at least the following steps B-1) to B-4).

[0056] B-1) A step of placing the recycled composite material in a mold (second mold, lower mold). B-2) A step of applying pressure while heating the mold (first pressing step) to a temperature above the melting point and below the thermal decomposition temperature of the thermoplastic resin if the thermoplastic resin is crystalline, or to a temperature above the glass transition temperature and below the thermal decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous. B-3) A step of applying pressure in one or more stages, with the pressure in the final stage being 1.2 to 100 times the pressure in the first pressing step (second pressing step). B-4) A step of adjusting the mold temperature to below the melting point if the thermoplastic resin is crystalline, or below the glass transition temperature if the thermoplastic resin is amorphous. By performing these steps, an integrally molded structure can be created.

[0057] [Common Features of Cold Press Molding and Hot Press Molding] Steps A-2) and B-3) are steps in which pressure is applied to the recycled composite material to obtain a molded product of the desired shape. The molding pressure is not particularly limited, but is preferably as low as possible within a range that allows the desired molded shape to be obtained. Specifically, a molding pressure of less than 30 MPa relative to the mold cavity projected area is preferred, more preferably 20 MPa or less, and even more preferably 10 MPa or less. A molding pressure of less than 30 MPa is preferred because it does not require capital investment or maintenance costs for a press machine. Naturally, various processes may be inserted between the above-mentioned press molding steps; for example, vacuum press molding, in which press molding is performed under vacuum, may be used.

[0058] 2 is a schematic diagram showing the configuration of a system 100 for determining a reuse or horizontal recycling strategy based on non-destructive testing information of used fiber-reinforced plastics according to a second embodiment of the present invention. The system 100 includes a server 110 and a client terminal 200 connected to the server 110 via information and communication networks 120 and 130. The information and communication networks 120 and 130 may be the same network, such as the Internet, or may be different networks.

[0059] The server 110 includes a processor 111, a main storage device 112, an auxiliary storage device 113, an input interface 114, an output interface 115, etc. The processor 111, the main storage device 112, and the auxiliary storage device 113 are similar to the processor 11, the main storage device 12, and the auxiliary storage device 13 of the first embodiment, respectively. In this embodiment, the auxiliary storage device 113 stores a mechanical property estimation program (a trained inference model) that has learned the association between non-destructive inspection information and mechanical property information using a data set of non-destructive inspection information and mechanical property information of known fiber-reinforced plastics as training data, and a policy decision program that decides on a policy for reuse or horizontal recycling of fiber-reinforced plastics based on the mechanical property information.

[0060] Non-destructive testing information for used fiber reinforced plastics is input to the input interface 114 from the client terminal 200 via the information communication network 120 and transmitted to the processor 111 .

[0061] The output interface 115 is connected to an output unit 230 (described later) via the information and communication network 130. Information on the mechanical property rank determined by the processor 111 and information on the reuse or horizontal recycling measures are output to the output interface 115, and the output interface 115 transmits the information on the mechanical property rank and the information on the reuse or horizontal recycling measures to the client terminal 200 via the information and communication network 130.

[0062] The client terminal 200 includes an input unit 220 and an output unit 230. Non-destructive testing information for used fiber-reinforced plastics is input from the input unit 220. The input non-destructive testing information is transmitted to the server 110 via the information and communication network 120. The output unit 230 receives information on mechanical property ranks and information on reuse or horizontal recycling measures from the server 110 via the information and communication network 130. The received information is output by the output unit 230. Note that while FIG. 2 illustrates an example in which the input unit 220 and the output unit 230 are provided in the same client terminal 200, the input unit 220 and the output unit 230 may be independent, or may be provided in different client terminals.

[0063] In this embodiment, non-destructive testing information for used fiber reinforced plastics is input via the input unit 220 of the client terminal 200, the input unit 220 transmits the non-destructive testing information to the server 110 via the information and communication network 120, the processor 111 executes a mechanical property estimation program stored in the auxiliary storage device 113 from the non-destructive testing information received by the server 110 to estimate the mechanical property information for the used fiber reinforced plastic, the processor 111 executes a measure determination program stored in the auxiliary storage device 113 to determine the mechanical property rank of the used fiber reinforced plastic and a measure for reuse or horizontal recycling, and transmits the determined mechanical property rank and the measure for reuse or horizontal recycling to the output unit 230 via the information and communication network 130, and the output unit 230 outputs information on the mechanical property rank or the measure for reuse or horizontal recycling.

[0064] Furthermore, the output unit 230 may output information such as the composition of the material of the used fiber-reinforced plastic and the number of times it has been reused or horizontally recycled. Hereinafter, the "information on the reuse or horizontal recycling measure" determined by the measure determination program, the "mechanical property information itself and information on the mechanical property rank" estimated by the mechanical property estimation program, and the "information on the composition of the material of the used fiber-reinforced plastic and the number of times it has been reused or horizontally recycled" are also simply referred to as "used fiber-reinforced plastic information."

[0065] The output unit 230 may assign the used fiber-reinforced plastic information to the used fiber-reinforced plastic. For example, a sticker on which the used fiber-reinforced plastic information is printed may be attached to the used fiber-reinforced plastic. A sticker on which the used fiber-reinforced plastic information is printed as text may be attached to the used fiber-reinforced plastic, or a sticker on which a barcode or two-dimensional code indicating the used fiber-reinforced plastic information is printed may be attached to the used fiber-reinforced plastic.

[0066] Furthermore, the output unit 230 may provide information indicating the location of the used fiber-reinforced plastic information to the used fiber-reinforced plastic. For example, the used fiber-reinforced plastic information may be stored in the server 110, and a sticker on which characters indicating a URL corresponding to the used fiber-reinforced plastic information or a two-dimensional code corresponding to the URL may be printed may be affixed to the used fiber-reinforced plastic.

[0067] The output unit 230 may also print or engrave on the surface of the used fiber-reinforced plastic characters indicating the used fiber-reinforced plastic information (for example, the letters A to D indicating the ranks described above), characters indicating the location (URL) of the used fiber-reinforced plastic information, a barcode, or a two-dimensional code. Alternatively, the used fiber-reinforced plastic information may be recorded on an RFID tag, and the RFID tag may be attached to the used fiber-reinforced plastic. By assigning the used fiber-reinforced plastic information to the used fiber-reinforced plastic in this way, the value of the used fiber-reinforced plastic can be properly evaluated based on the information assigned to the used fiber-reinforced plastic, even in a location distant from the client terminal 200, and the reuse or horizontal recycling described below can be performed.

[0068] The second embodiment is effective when recycled product dealers who collect and resell used fiber-reinforced plastics are different from fiber-reinforced plastic manufacturers. In the automotive industry, recycled product dealers disassemble used automobiles to extract and sell recyclable parts and materials, thereby promoting waste reduction and effective resource utilization. However, recycled product dealers cannot know the extent to which the mechanical properties of used fiber-reinforced plastics remain. On the other hand, fiber-reinforced plastic manufacturers generally do not recover parts from scrapped automobiles.

[0069] However, recycled product dealers specialize in reusing parts and materials, and are unable to determine the optimal method for recycling. Therefore, they make decisions based on appearance. As a result, the value of used fiber-reinforced plastics is unknown, and recycling or reuse methods are not optimized. For example, if recycled product dealers or inspection companies that receive recycled products conduct non-destructive testing and input the non-destructive testing information into the input unit 220, which is connected to the information and communication networks 120 and 130, and obtain the mechanical property ranking of used fiber-reinforced plastics and reuse or horizontal recycling measures from the mechanical property estimation program and the measure determination program stored in the server 110, the appropriate value of used fiber-reinforced plastics, which was previously unknown, can be determined.

[0070] Meanwhile, fiber-reinforced plastic manufacturers can generate a mechanical property estimation program and a policy determination program for estimating mechanical property information of fiber-reinforced plastics before shipping them. A client terminal 200 is provided to a recycled product dealer, and the mechanical property estimation program and policy determination program are stored on the fiber-reinforced plastic manufacturer's server 110. The mechanical property estimation program and policy determination program determine a mechanical property rank and a reuse or horizontal recycling policy based on non-destructive testing information of used fiber-reinforced plastics input from the client terminal 200 via the information and communication network 120. Information on the mechanical property rank and the reuse or horizontal recycling policy is then provided to the client terminal 200 via the information and communication network 130, thereby providing a system that enables recycled product dealers to ascertain the appropriate value of used fiber-reinforced plastics. For convenience, the recycled product dealer and the fiber-reinforced plastic manufacturer are referred to as recycled product dealers and fiber-reinforced plastic manufacturers, but this is not limiting and the two parties may be entities with completely different business types.

[0071] [Reinforcing Fiber] The type of reinforcing fiber used in fiber-reinforced plastics can be appropriately selected depending on the application of the fiber-reinforced plastic, and is not particularly limited. Either inorganic or organic fibers can be suitably used as the reinforcing fiber. Examples of the inorganic fibers include carbon fibers, activated carbon fibers, graphite fibers, glass fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, alumina fibers, natural mineral fibers (such as basalt fibers), boron fibers, boron nitride fibers, boron carbide fibers, and metal fibers.

[0072] [Reinforcing Fiber] In this specification, the reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, aramid fiber, glass fiber, polyester fiber, nylon fiber, polypropylene fiber, and polyethylene fiber, and more preferably carbon fiber or glass fiber.

[0073] [Reinforcing Fiber: Carbon Fiber] When carbon fiber is used as the fiber, generally known carbon fibers include polyacrylonitrile (PAN)-based carbon fiber, petroleum / coal pitch-based carbon fiber, rayon-based carbon fiber, cellulose-based carbon fiber, lignin-based carbon fiber, phenol-based carbon fiber, and vapor-grown carbon fiber, and any of these carbon fibers can be suitably used in the present invention.

[0074] [Reinforcing fiber: glass fiber] The case where the reinforcing fiber used in the present invention is glass fiber will be described. The glass fiber used in the present invention may be any glass fiber as long as it is generally called glass fiber. There is no particular limitation on the glass composition such as A-glass, C-glass, E-glass, etc., and in some cases, TiO ２ , S.O. ３ , P ２ O ５ The glass fiber may contain components such as E-glass RS240QR-483 (count: 2400 g / 1000 m) manufactured by Nitto Boseki Co., Ltd., for example.

[0075] [Form of Reinforcing Fiber] In the present invention, there is no particular limitation on the form of the reinforcing fiber. However, the following describes continuous fibers, which the present inventors have used as a specific example. However, the present invention is not limited to continuous fibers. Continuous fibers refer to reinforcing fibers in which the reinforcing fibers are not cut into short fibers but are aligned in a continuous state as reinforcing fiber bundles. For the purpose of obtaining used fiber-reinforced plastics with excellent mechanical properties, it is preferable to use continuous reinforcing fibers. More specifically, continuous fibers preferably refer to fibers with a length of 1 m or more, and are used by processing them into woven fabrics such as woven fabrics or knitted fabrics and then impregnating them with resin by hand layup or the like, or by impregnating continuous fibers with uncured resin to form prepregs.

[0076] [Used Fiber-Reinforced Plastic] Fiber-reinforced plastic is plastic reinforced with reinforcing fibers. Used fiber-reinforced plastic is, for example, waste generated after fiber-reinforced plastic is used in automobiles, aircraft, buildings, etc. and is released to the general market. Hereinafter, an example of an embodiment carried out by the present inventors will be described, but the present invention is not limited to the fiber-reinforced plastic a described below.

[0077] 1. Fiber-reinforced plastic The fiber-reinforced plastic a is a molded body obtained by molding a plate-shaped material, and may be a molded body using a thermoplastic resin or a molded body using a thermosetting resin.

[0078] 2. Fiber-reinforced plastic as a unidirectional material The fiber-reinforced plastic a is preferably a unidirectional material. A unidirectional material refers to a material in which continuous reinforcing fibers with a length of 100 mm or more are arranged in one direction inside the fiber-reinforced plastic a. The unidirectional material may be a laminate of multiple continuous reinforcing fibers. In particular, when the fiber-reinforced plastic a is a unidirectional material and is a molded body using a thermosetting prepreg, the influence of fiber orientation on the mechanical properties is small. This can improve the accuracy of estimating mechanical property information using the model described below.

[0079] 3. Fiber-reinforced plastic reinforced with discontinuous fibers The fiber-reinforced plastic may be reinforced with discontinuous fibers. In this case, the weight-average fiber length of the reinforcing fibers is preferably 1 mm or more and 100 mm or less, more preferably 3 mm or more and 80 mm or less, and even more preferably 5 mm or more and 60 mm or less. In other words, the reinforcing fibers are preferably discontinuous fibers.

[0080] When discontinuous fibers are used, the state of existence of the reinforcing fibers in the fiber-reinforced plastic is not particularly limited, and may be, for example, a state of being arranged in one direction or a state of being randomly arranged. From the viewpoint of uniformity of the shape rigidity and strength of the fiber-reinforced plastic, it is preferable that the reinforcing fibers be in a state of being randomly dispersed in two dimensions, in which the long axis directions of the reinforcing fibers are randomly dispersed in the in-plane direction of the fiber-reinforced plastic.

[0081] The degree of orientation of two-dimensionally randomly dispersed reinforcing fibers is evaluated by determining the ratio of the tensile modulus in two mutually perpendicular directions. The reinforcing fibers can be evaluated as being two-dimensionally randomly dispersed if the (Eδ) ratio, calculated by dividing the larger of the tensile modulus values ​​measured in any direction of the fiber-reinforced plastic and the direction perpendicular to that direction by the smaller, is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less. Since curved surfaces are included, a method for evaluating two-dimensional random dispersion in the in-plane direction is to make an incision in the curved surface, heat it above the softening temperature, and solidify it back into a flat plate shape. Then, test pieces are cut out and the tensile modulus is determined, allowing the state of random dispersion in the two-dimensional direction to be confirmed.

[0082] Furthermore, when discontinuous fibers are used, the fiber reinforced plastics compared to known fiber reinforced plastics are such that, when the fiber length of the reinforcing fiber bundle is Li, the single fiber diameter of the reinforcing fiber constituting the reinforcing fiber bundle is Di, and the number of single fibers contained in the reinforcing fiber bundle is Ni, Li is 1 mm or more and 100 mm or less, and Li / (Ni × Di ２ ) is 8.0 x 10 １ 3.3 x 10 ３ It is preferable that the molded body contains the following reinforcing fiber bundles A. The volume ratio of the reinforcing fiber bundles A to the total reinforcing fibers contained in the molded body is preferably 50 to 100 vol %, more preferably 70 to 90 vol %.

[0083] [Preferred Fiber-Reinforced Plastic] The fiber-reinforced plastic contains reinforcing fibers and a matrix resin as essential components, and contains other components as optional components, and has a porosity V of the fiber-reinforced plastic calculated by the following formulas (A) and (B): ｒ is preferably 10% or less. ｒ = (t ２ -t １ ) / t ２ ×100... Formula (A) t １ = (W ｆ / D ｆ +W ｍ / D ｍ +W ｚ / D ｚ ) ÷ unit area (mm ２) ... Formula (B) t １ t: Theoretical thickness of fiber reinforced plastic (mm) ２ : Measured thickness of fiber reinforced plastic (mm) D ｆ : Density of reinforcing fiber (mg / mm ３ ) D ｍ : density of matrix resin (mg / mm ３ ) D ｚ : Density of other components (mg / mm ３ ) W ｆ W: Mass of reinforcing fiber (mg) ｍ W: Mass of matrix resin (mg) ｚ : Mass of other components (mg) Porosity V ｒ The porosity V is more preferably 5% or less, and even more preferably 3% or less. ｒ If is within this range, the accuracy of the mechanical property estimation of the present invention is improved.

[0084] [Production of Fiber-Reinforced Plastic] For example, fiber-reinforced plastic can be prepared as follows: 1. Example 1. 1.1 Materials Reinforcement fiber: Carbon fiber "Tenax (registered trademark)" STS40-24K (tensile strength 4,300 MPa, tensile modulus 240 GPa, number of filaments 24,000, fineness 1,600 tex, elongation 1.8%, density 1.78 g / cm ３ , manufactured by Teijin Limited) Base resin: Thermosetting resin composition mainly composed of epoxy resin

[0085] 1.2. Preparation of Unidirectional Prepreg Unidirectional prepreg was prepared by the hot melt method as follows. First, the thermosetting resin composition was applied to release paper using a coater to prepare a resin film. Next, the carbon fiber bundle was fed from the creel, passed through a comb to align the pitch between the carbon fiber bundles, and then spread through a fiber spreading bar to prepare a prepreg having a fiber mass per unit area (fiber basis weight) of 100 g / m. ２ The carbon fibers were aligned in one direction to form a sheet. The resin films were then placed on both sides of the carbon fibers, heated and pressurized to impregnate them with the thermosetting resin composition, and wound up on a winder to produce a unidirectional prepreg. The resin content of the resulting unidirectional prepreg was 30 wt %.

[0086] 1.3. Fabrication of Fiber-Reinforced Plastic Eleven unidirectional prepregs were manually laminated in the 0° direction to obtain a prepreg laminate with a laminate configuration of

[011] T. The prepreg laminate was placed in a bag film, placed in a mold, and heated in an autoclave to 130°C for 120 minutes to harden it, producing a 1 mm-thick CFRP molded product (a unidirectional carbon fiber-reinforced thermosetting resin molded product, i.e., fiber-reinforced plastic).

[0087] 2. Example 2.2.1 Preparation of Composite Material Toho Tenax Co., Ltd.'s "Tenax" (registered trademark) STS40-24K carbon fiber (average fiber diameter 7 μm, 24,000 single fibers) cut to a fiber length of 20 mm was used as the carbon fiber, and Unitika Ltd.'s nylon 6 resin A1030 was used as the resin. A carbon fiber and nylon 6 resin composite material with two-dimensionally randomly oriented carbon fibers was prepared based on the method described in U.S. Patent No. 8,946,342. The resulting composite material was heated at 2.0 MPa for 5 minutes in a press heated to 260°C to obtain a flat plate-shaped material with an average thickness of 2.5 mm and dimensions of 475 mm x 350 mm.

[0088] Analysis of the carbon fibers contained in the flat plate-shaped material revealed that the carbon fiber volume fraction (Vf) was 35%, the fiber length of the carbon fibers was constant, and the weight average fiber length was 20 mm. 2.1 Preparation of fiber-reinforced plastic

[0089] The plate-shaped material was dried in a hot air dryer at 120° C. for 4 hours, and then heated to 290° C. using an infrared heater. The material was then placed in a mold consisting of upper and lower dies, the upper die was lowered, and the material was pressed at a pressure of 20 MPa (the time from the start of pressurization until the pressure reached 20 MPa was 1 second) for 1 minute to produce a cold-press molded body.

[0090] [Measurement of Tensile Modulus and Tensile Strength] As a specific example of the breaking strength or modulus of elasticity of the present invention, the inventors measured the tensile modulus and tensile strength of a fiber-reinforced plastic as follows. The fiber-reinforced plastic was processed into a test piece shape (length 250 mm × width 15 mm) using a water jet, and a tab made of a glass fiber-reinforced resin-based fiber-reinforced plastic was attached to it. A 0° direction tensile test was performed using a universal testing machine in accordance with ASTM D3039 at a test speed of 2 mm / min, and the tensile modulus and tensile strength of the fiber-reinforced plastic were calculated.

[0091] Furthermore, in the present invention, the fiber-reinforced plastics used for machine learning are not used fiber-reinforced plastics that have been released onto the general market. A model for predicting the mechanical properties of fiber-reinforced plastics was created by performing machine learning on tens to thousands of fiber-reinforced plastics that had been intentionally cracked.

[0092] [Vibration Property Information] In the present invention, the non-destructive testing information is preferably vibration property information. The reinforcing fibers contained in fiber-reinforced plastics and the plastic matrix resin have different elastic moduli. Therefore, in fiber-reinforced plastics, the vibration properties may change depending on the orientation and distribution of the reinforcing fibers distributed in the matrix resin. Furthermore, in fiber-reinforced plastics, the mechanical properties may change depending on the orientation and distribution of the reinforcing fibers. Therefore, there is a correlation between the vibration properties and the mechanical properties of fiber-reinforced plastics. The vibration testing method used to acquire the vibration property information is not particularly limited, and any testing method can be used as long as it can detect internal defects, voids, or foreign matter in used fiber-reinforced plastics without destroying the used fiber-reinforced plastics. Furthermore, the finite element method (FEA) may be used to acquire the vibration property information used in machine learning. The vibration property information is preferably obtained by converting information obtained by the vibration testing or the finite element method into an image, and it is particularly preferable that the converted image is a wavelet image.

[0093] Specific wavelet images are shown in Figures 3A to 3D. An autowavelet system manufactured by Elmec was used to acquire these images. Vibration measurements were performed using impulse excitation under free-free boundary conditions. A 2 mm diameter hole was drilled in the molded body, and nylon line (22-8231 manufactured by Takagi Rope Industry) was passed through the hole and the body was suspended from a beam, achieving free-free boundary conditions. An acceleration pickup sensor (PCB PIEZOTRONICS 356A01) was attached to the fiber-reinforced plastic, and vibration was applied using an impulse hammer (GK-3100 manufactured by Ono Sokki). Data measurement and analysis were performed using a real-time acoustic vibration analysis system (DS-3000 manufactured by Ono Sokki). The sampling frequency was set to 2000 Hz. The obtained vibration data was analyzed using wavelet analysis software (BIOMAS manufactured by Elmec), and a wavelet image was obtained, with the vibration frequency on the vertical axis, time on the horizontal axis, and the vibration amplitude on the brightness and hue. Figures 3A and 3B are wavelet images of a fiber-reinforced plastic without defects, while Figures 3C and 3D are wavelet images of a fiber-reinforced plastic with defects. Note that Figures 3A to 3D are binarized images, and the more white there is, the greater the amplitude of vibration at that frequency. Reference numeral 803 in Figure 3C and reference numeral 804 in Figure 3D represent spherical patterns, indicating that 450 Hz vibrations were occurring intermittently. It was confirmed that the portions referenced 803 in Figure 3C and 804 in Figure 3D are clearly different from the portions referenced 801 in Figure 3A and 802 in Figure 3B.

[0094] [Vibration Damping of Vibration Characteristics] The image preferably includes information on vibration damping. Vibration damping is a vibration phenomenon in which the amplitude decreases over time in vibration time history data. For example, looking at the patterns indicated by reference numeral 801 in FIG. 3A and reference numeral 802 in FIG. 3B, the vertical length of the white pattern at approximately 450 Hz in FIG. 3A and FIG. 3B decreases over time, indicating that the vibration at approximately 450 Hz is damping. In this case, the rate at which the vibration at approximately 450 Hz decays is faster for reference numeral 801 in FIG. 3A than for reference numeral 802 in FIG. 3B. For the fiber-reinforced plastics measured using the data in FIG. 3A to FIG. 3D, the faster the rate at which the vibration at approximately 450 Hz decays, the smaller the tensile modulus and tensile strength. Note that FIG. 3A to FIG. 3D are merely examples. The frequency at which vibration damping occurs varies depending on the shape and natural frequency of the test specimen. Furthermore, mechanical properties other than the tensile modulus and tensile strength do not necessarily decrease as the rate at which the vibration damps increases.

[0095] [Acoustic Characteristics] The non-destructive inspection information in the present invention may be acoustic characteristics information.

[0096] [Frequency] 1. Sampling Frequency Generally, the sampling frequency refers to the frequency at which samples are taken per unit time in sampling, a process necessary to convert analog waveforms such as audio into digital data. To accurately sample a waveform, sampling must be performed at a frequency at least twice the bandwidth of the frequency components of the waveform. In the present invention, the non-destructive testing information is vibration characteristic information or acoustic characteristic information, and the sampling frequency when acquiring non-destructive testing information for used fiber-reinforced plastics is greater than 0 Hz. The lower limit is preferably 50 Hz or more, more preferably 250 Hz or more, even more preferably 5,000 Hz or more, and even more preferably 10,000 Hz or more. On the other hand, the upper limit is preferably 50,000 Hz or less, more preferably 40,000 Hz or less, and even more preferably 30,000 Hz or less. Therefore, the sampling frequency is preferably 50 Hz or more and 50,000 Hz or less, more preferably 250 Hz or more and 50,000 Hz or less, even more preferably 5,000 Hz or more and 40,000 Hz or less, and even more preferably 10,000 Hz or more and 30,000 Hz or less. From another perspective, the sampling frequency is preferably at least twice the frequency at which the above-mentioned vibration attenuation occurs. From another perspective, the sampling frequency when acquiring the vibration characteristics of used fiber-reinforced plastics is preferably at least twice the natural frequency of the first-order mode described below, and more preferably at least twice the natural frequency of the second-order mode.

[0097] 2. Natural Frequency of the Primary Mode When the non-destructive testing information is vibration property information, the natural frequency of the primary mode of a molded article using fiber-reinforced plastic is preferably between 0 Hz and 1,000 Hz. Within this range, for example, when the molded article is installed in an automobile, it will not resonate with vibrations from the outside or the engine compartment, improving comfort. More preferably, the natural frequency of the primary mode of known fiber-reinforced plastics and used fiber-reinforced plastics is between 0 Hz and 500 Hz. On the other hand, when the non-destructive testing information is acoustic property information, the natural frequency of the primary mode of a molded article using fiber-reinforced plastic is preferably between 0 Hz and 20,000 Hz, and more preferably between 0 Hz and 10,000 Hz.

[0098] [Temperature Distribution Image] The temperature distribution information is preferably a temperature distribution image, which is an image of the temperature distribution of the fiber reinforced plastic, which is the object to be inspected, captured by an infrared camera.

[0099] The thermal conductivity of the reinforcing fibers contained in fiber-reinforced plastics differs from that of the matrix plastic. Therefore, in fiber-reinforced plastics, the temperature distribution can change depending on the orientation and distribution of the reinforcing fibers within the matrix resin. In addition, the mechanical properties of fiber-reinforced plastics can change depending on the orientation and distribution of the reinforcing fibers. For this reason, there is a correlation between the temperature distribution image and the mechanical properties of fiber-reinforced plastics.

[0100] Specific temperature distribution images are shown in Figure 4. Figure 4 shows active thermography images of a fiber-reinforced plastic containing voids. To obtain these images, the active thermography measurement was performed by clamping the fiber-reinforced plastic specimen and installing two halogen lamps (Caster CHP500) so that they could irradiate the surface of the fiber-reinforced plastic at 45° angles to the left and right. The heat emitted from these two halogen lamps was reflected by the surface of the fiber-reinforced plastic, and this reflected heat was measured with an infrared camera (FLIR Systems A615). The heat source frequency was 0.1 Hz, the frame rate was 25 Hz, and the imaging time was 125 seconds. It was confirmed that defects in the fiber-reinforced plastic were visualized at 1801 in Figure 4. The presence of such defects tends to reduce mechanical properties such as fracture strength and elastic modulus in the defective areas of the fiber-reinforced plastic.

[0101] It is clear that no matter how hard a person tries, they cannot estimate the mechanical property information of a fiber-reinforced plastic from the temperature distribution image in Figure 4. In the mechanical property estimation device 1 of this embodiment, a mechanical property estimation model is generated using training data that associates a temperature distribution image of a known fiber-reinforced plastic with mechanical property information obtained by measuring the known fiber-reinforced plastic from which the temperature distribution image was obtained. By using the mechanical property estimation program of this embodiment, it is possible to estimate the mechanical property information of a used fiber-reinforced plastic from a temperature distribution image of the fiber-reinforced plastic, and therefore it is possible to instantaneously estimate mechanical property information, which a skilled worker cannot estimate no matter how hard he or she tries, without actually measuring it.

[0102] There are no particular limitations on the method for acquiring temperature distribution images; for example, infrared thermography can be used. Infrared thermography is a type of non-destructive testing that uses the surface temperature and temperature changes of an object to determine the internal condition. Measurements performed by external excitation of a non-heat-generating object are called active thermography. The excitation method used in infrared thermography is not particularly limited, and can involve either heating or cooling. However, it is preferable to heat the object externally and capture infrared thermography images. Heating can be achieved by radiant heat, ultrasonic vibration energy, electromagnetic force, or sunlight, while cooling can be achieved by natural cooling, heat of vaporization, or low-temperature gas spraying. Temperature changes occur on the heated or cooled surface, and these temperature changes can be detected by an infrared sensor to estimate the internal condition. When heating fiber-reinforced plastics containing fibers and thermoplastic resins, the heating temperature is preferably below the softening point of the thermoplastic resin. Observation after heating below the softening point is less likely to adversely affect the molded product.

[0103] [Finite Element Method] The mechanical property information or non-destructive testing information of a fiber-reinforced plastic whose mechanical property information and non-destructive testing information are known (hereinafter, sometimes simply referred to as a known fiber-reinforced plastic) is preferably obtained by the finite element method. Here, the finite element method (FEM) is a numerical analysis technique that can numerically obtain approximate solutions to differential equations that are difficult to solve analytically. By creating an analytical model in which material parameters identified in advance by comparing actual measurements and analysis are applied to the shape of the fiber-reinforced plastic, this information can be obtained by the finite element method without actually measuring the mechanical properties or non-destructive testing of the fiber-reinforced plastic, and can be used as training data for machine learning.

[0104] As described above, the inspection system of this embodiment allows for the estimation of mechanical property information of used fiber-reinforced plastic a from non-destructive inspection information (preferably vibration inspection images, acoustic property images, or temperature distribution images) of the used fiber-reinforced plastic a. The inventions described in International Publication Nos. 2019 / 151393 and 2019 / 151394 merely replace what humans would normally judge by looking at an image or object being measured with a neural network. In other words, these inventions use photographed food as the inspection target, allowing humans to easily determine the presence or absence of foreign matter in the food. Meanwhile, the mechanical property information is a numerical value or a ranking equivalent thereto, and the non-destructive inspection information (preferably vibration inspection images, acoustic property images, or temperature distribution images) visualizes or quantifies the internal state of the used fiber-reinforced plastic. In other words, even if a skilled worker looks at the non-destructive inspection information, they cannot infer mechanical property information from it. For example, no matter how hard a human tries, it is clear that they cannot infer mechanical property information from the vibration inspection images of Figures 3A to 3D or the temperature distribution image of Figure 4. By using the inspection device 1 of this embodiment, it is possible to instantly estimate mechanical property information that even a skilled worker would be unable to estimate no matter how hard he tries, without actually measuring it. In the above embodiment, an example has been described in which mechanical property information is estimated from non-destructive inspection information of a plate-shaped used fiber-reinforced plastic, but the present invention is not limited to plate-shaped used fiber-reinforced plastics, and it is also possible to estimate mechanical property information from non-destructive inspection information for used fiber-reinforced plastics having a three-dimensional shape.

[0105] 1: Device 10: Computer 11, 111: Processor 12, 112: Main memory device 13, 113: Auxiliary memory device 14, 114: Input interface 15, 115: Output interface 20, 220: Input section 30, 230: Output section 110: Server 200: Client terminal 801, 802, 803, 804: Waveform showing vibration damping 1801: "Void" (defect) found in fiber reinforced plastic

Claims

1. An apparatus for determining a reuse or horizontal recycling measure based on non-destructive testing information for used fiber reinforced plastics, comprising: an input unit for inputting the non-destructive testing information for the used fiber reinforced plastic; a memory unit storing a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information for known fiber reinforced plastics as training data to learn the association between the non-destructive testing information and the mechanical property information and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program for determining a reuse or horizontal recycling measure for the fiber reinforced plastic based on the mechanical property information; a processor that executes the mechanical property estimation program to estimate the mechanical property information for the used fiber reinforced plastic from the non-destructive testing information for the used fiber reinforced plastic, and executes the policy determination program to determine a reuse or horizontal recycling measure for the used fiber reinforced plastic from the estimated mechanical property information; and an output unit that outputs information on the reuse or horizontal recycling measure for the used fiber reinforced plastic.

2. A system for determining a reuse or horizontal recycling measure in accordance with non-destructive testing information for used fiber reinforced plastics, comprising: a server; and a client terminal connected to the server through an information and communication network, wherein the server comprises: a memory unit storing a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information for known fiber reinforced plastics as training data to learn the association between non-destructive testing information and mechanical property information and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program that determines a reuse or horizontal recycling measure for the fiber reinforced plastic based on the mechanical property information; a processor that executes the mechanical property estimation program and the policy determination program; and a server-side communication interface that inputs non-destructive testing information for used fiber reinforced plastics received from the client terminal through the information and communication network to the processor, and transmits information on a reuse or horizontal recycling measure for the used fiber reinforced plastic estimated by the mechanical property estimation program and the policy determination program from the received non-destructive testing information to the client terminal through the information and communication network, wherein the client terminal A system comprising: an input unit for inputting non-destructive testing information for used fiber reinforced plastics; a client-side communication interface for transmitting the non-destructive testing information to the server through the information and communication network and receiving from the server information on reuse or horizontal recycling measures for the used fiber reinforced plastics inferred from the non-destructive testing information; and an output unit for outputting the information on reuse or horizontal recycling measures for the used fiber reinforced plastics received from the server through the information and communication network.

3. A method for determining a measure for reusing or horizontally recycling used fiber-reinforced plastics, the method comprising the steps of: acquiring non-destructive testing information for the used fiber-reinforced plastic; estimating the mechanical property information of the used fiber-reinforced plastic from the non-destructive testing information of the used fiber-reinforced plastic using a prediction model trained by machine learning using the mechanical property information and non-destructive testing information of a fiber-reinforced plastic sample, the mechanical property information and non-destructive testing information of which are known, as training data; determining a measure for reusing or horizontally recycling the used fiber-reinforced plastic based on the inferred mechanical property information; and outputting information on the determined reuse or horizontal recycling measure.

4. A horizontal recycling method for used fiber-reinforced plastics, which involves recycling by remolding used fiber-reinforced plastics that have been decided upon for horizontal recycling by the method described in claim 3, wherein the fiber-reinforced plastics contain reinforcing fibers and thermoplastic resin, and the molding method used in the remolding is press molding.

5. The horizontal recycling method for used fiber-reinforced plastics according to claim 4, wherein the used fiber-reinforced plastics are press-molded products.

6. A method for horizontally recycling used fiber-reinforced plastics according to any one of claims 4 to 5, wherein the horizontal recycling does not include a step of isolating reinforcing fibers from the fiber-reinforced plastic.

7. A horizontal recycling method for used fiber reinforced plastics according to any one of claims 4 to 6, wherein the used fiber reinforced plastics contain discontinuous reinforcing fibers, and the relationship between the weight average fiber length Lw1 of the reinforcing fibers contained in the used fiber reinforced plastic and the weight average fiber length Lw2 of the reinforcing fibers contained in the fiber reinforced plastic after the used fiber reinforced plastic has been horizontally recycled satisfies 2 mm≦Lw2≦Lw1.

8. A horizontal recycling method for used fiber-reinforced plastics according to claim 7, wherein the weight average fiber length Lw1 contained in said used fiber-reinforced plastics is 3 mm or more.

9. The reinforcing fibers contained in the used fiber reinforced plastics are such that, when the fiber length of the reinforcing fiber bundle is Li, the single fiber diameter of the reinforcing fiber constituting the reinforcing fiber bundle is Di, and the number of single fibers contained in the reinforcing fiber bundle is Ni, Li is 1 mm or more and 100 mm or less, and Li / (Ni × Di ２ ) is 8.0 x 10 １ 3.3 x 10 ３ The horizontal recycling method for used fiber-reinforced plastics according to claim 7 or 8, comprising the following reinforcing fiber bundles:

10. A method for horizontally recycling used fiber-reinforced plastics according to any one of claims 4 to 9, wherein the used fiber-reinforced plastics have been used in automobile parts, and the fiber-reinforced plastics after horizontal recycling of the used fiber-reinforced plastics are reused as automobile parts.

11. A horizontal recycling method for used fiber-reinforced plastics according to any one of claims 4 to 10, wherein the non-destructive inspection information is a vibration inspection image, an acoustic characteristic image, a temperature distribution image, or numerical data of natural frequencies.

12. A horizontal recycling method for used fiber-reinforced plastics according to any one of claims 4 to 10, wherein the mechanical property information is information relating to the elastic modulus or breaking strength of the used fiber-reinforced plastics.

13. A horizontal recycling method for used fiber-reinforced plastics as described in claim 12, wherein the information on the elastic modulus includes the elastic modulus or a rank when the elastic modulus is ranked, and the information on the breaking strength includes the breaking strength or a rank when the breaking strength is ranked.

14. A method for horizontally recycling used fiber-reinforced plastics as described in claim 13, wherein the information regarding the elastic modulus or breaking strength includes at least one of the following: information indicating that the elastic modulus or breaking strength is difficult to estimate; information indicating that the elastic modulus or breaking strength corresponds to used fiber-reinforced plastics that can be reused or horizontally recycled; and information indicating that the elastic modulus or breaking strength corresponds to used fiber-reinforced plastics that cannot be reused or horizontally recycled.

15. A program for determining a reuse or horizontal recycling measure based on non-destructive testing information for used fiber reinforced plastics, the program comprising: a mechanical property estimation program that uses a dataset of non-destructive testing information and mechanical property information for known fiber reinforced plastics as training data to learn the relationship between the non-destructive testing information and the mechanical property information, and estimates the mechanical property information using the non-destructive testing information as input; and a policy determination program for determining a reuse or horizontal recycling measure for the fiber reinforced plastic based on the mechanical property information, wherein the program causes a processor to execute the mechanical property estimation program to estimate the mechanical property information for the used fiber reinforced plastic from the non-destructive testing information for the used fiber reinforced plastic, and to execute the policy determination program to determine a reuse or horizontal recycling measure for the used fiber reinforced plastic from the estimated mechanical property information.

16. The device according to claim 1, wherein the output unit provides information on reuse or horizontal recycling strategies to the used fiber-reinforced plastic.

17. The system according to claim 2, wherein the output unit provides information on reuse or horizontal recycling strategies to the used fiber-reinforced plastic.

18. The method according to claim 3, wherein in the step of outputting information on the determined reuse or horizontal recycling measure, information on the reuse or horizontal recycling measure is imparted to the used fiber-reinforced plastic.

19. The program according to claim 15, further comprising a program for applying the reuse or horizontal recycling strategy determined by the strategy determination program to the used fiber reinforced plastic.

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