Method for treating plastic-containing material, and device for treating plastic-containing material

Abstract

To provide a method for treating a plastic-containing material by means of lepidopteran insects.SOLUTION: A method for treating a plastic-containing material includes an introduction step of introducing the larvae of lepidopteran insects and a plastic-containing material into the cultivation space; an adjustment step of adjusting at least the occupancy ratio of the plastic-containing material in the cultivation space; and a feeding step of feeding the plastic-containing material to the larvae of lepidopteran insects in the cultivation space.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to methods for processing plastic-containing materials and to apparatus for processing plastic-containing materials. [Background technology]

[0002] It has been known that certain insect larvae are bred as bait for fishing. Since bait for fishing needs to be live bait, various methods for delaying pupation have been proposed, such as those in Patent Documents 1 to 4.

[0003] On the other hand, it has been pointed out that certain types of plastics are biodegraded by the larvae of certain lepidopteran insects. For example, Non-Patent Document 1 shows that when a PE film is left in direct contact with Galleria mellonella larvae, holes begin to appear in the PE film after a certain period of time, and the PE film loses mass. Non-Patent Document 2 also reveals that Galleria mellonella larvae feed on polyethylene (PE) and polystyrene (PS). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-165065 [Patent Document 2] Japanese Patent Application Publication No. 5-41936 [Patent Document 3] Japanese Patent Application Publication No. 3-285630 [Patent Document 4] Japanese Patent Application Publication No. 1-132324 [Non-patent literature]

[0005] [Non-Patent Document 1] Bombeli et al.(2017) Current Biology 27, P283-293 [Non-Patent Document 2] Lou et al. (2020) Environ. Sci. Technol. 2020, 54, 5, 2821-2831 [Non-Patent Document 3] Morimoto (1960) Journal of the Japanese Society of Applied Zoology and Entomology 4, 4,197-202 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0006] Conventional methods for recycling plastics include chemical recycling, in which used plastics are decomposed and refined into plastic raw materials and then polymerized, and material recycling, in which used plastics are turned into flakes or pellets and then processed into molded products such as fibers and sheets. However, improvements are needed in both cases in terms of production costs, environmental impact, required facilities, etc.

[0007] In addition, according to the above-mentioned conventional methods, when the plastic to be treated is of a single type, it is possible to efficiently decompose and recycle the plastic, but when multiple types of plastic are mixed, there is a problem that the efficiency of the treatment decreases. In addition, when the plastic to be treated contains materials other than plastic, for example, when it is a laminate with a metal material, or when food stains are attached, there is also a problem that the efficiency of the treatment decreases.

[0008] As shown in the above-mentioned non-patent literature, if it becomes possible to decompose plastic-containing materials using organisms, there are advantages such as low energy consumption and low costs for required equipment. In addition, if useful substances can be obtained as a result of the decomposition of plastic-containing materials using organisms, it can contribute to the transition to a circular economy in the future. However, the treatment of plastic-containing materials using the above-mentioned organisms has not yet reached the level of practical application.

[0009] For the reasons described above, the present inventors have conducted extensive research into the decomposition mechanism of plastic-containing materials by certain types of larvae, and have examined whether plastic-containing materials can be efficiently treated throughout the entire process, from the growth of the larvae to the decomposition of the plastic-containing materials, leading to the present disclosure. [Means for solving the problem]

[0010] The method for processing plastic-containing materials in this embodiment is characterized by comprising (1) a throwing process for throwing lepidopteran insect larvae and plastic-containing materials into a rearing space, an adjustment process for adjusting at least the occupancy rate of the plastic-containing materials in the rearing space, and a feeding process for feeding the plastic-containing materials to the lepidopteran insect larvae within the rearing space.

[0011] In the method for treating plastic-containing materials described above in (1), it is preferable that in the adjusting step (2), the occupancy rate is adjusted to exceed 1.09%.

[0012] In the method for treating a plastic-containing material according to (1) or (2) above, (3) it is preferable that the plastic contained in the plastic-containing material is selected from the group consisting of polyester, polyolefin, polystyrene, polyamide, and paraffin.

[0013] In the method for treating plastic-containing materials of (1) or (2) above, (4) it is preferable that the plastic contained in the plastic-containing material is polyolefin, and that in the adjustment step, the occupancy rate is adjusted to be 2.0 to 8.0%.

[0014] In the method for treating plastic-containing materials of (1) or (2) above, (5) it is preferable that the plastic contained in the plastic-containing material is polyester, and that in the adjusting step, the occupancy rate is adjusted to be 1.2 to 4.0%.

[0015] In the method for treating a plastic-containing material according to (1) or (2) above, (6) it is preferable that the plastic-containing material contains two or more types of plastics.

[0016] In the method for treating a plastic-containing material according to the above (1) or (2), (7) it is preferable that the plastic-containing material is a laminate.

[0017] In the method for treating plastic-containing materials described above in (1) or (2), (8) the form of the plastic-containing material is preferably at least one of a film, a cup, a pouch, a pellet, a bottle, a powder, a fiber, or a capsule.

[0018] In the method for treating plastic-containing materials described above in (1) or (2), (9) the larvae of the Lepidoptera insect are preferably Galleria mellonella larvae.

[0019] The plastic-containing material processing device of this embodiment is characterized by comprising (10) a breeding tank capable of housing and raising lepidopteran insect larvae, and an adjustment device capable of at least adjusting the occupancy rate of plastic-containing material contained in the breeding tank and consumed by the larvae. Effect of the Invention

[0020] According to the present disclosure, it is possible to provide an efficient method for treating plastic-containing materials using lepidopteran insect larvae, and an apparatus for treating plastic-containing materials. [Brief description of the drawings]

[0021] [Figure 1] FIG. 13 is a graph showing the change over time in the proportion of larval forms in an example. [Diagram 2] FIG. 1 shows the change in food intake over time and the total amount in the Examples and Reference Examples. [Diagram 3] FIG. 13 is a graph showing the change over time in the proportion of larval forms in another example. [Figure 4]FIG. 13 is a graph showing the change in food intake over time and the total amount in other examples and a reference example. [Diagram 5] FIG. 13 is a graph showing the change over time in the proportion of larval forms in another example. [Figure 6] FIG. 13 is a graph showing the change in food intake over time and the total amount in other examples and a reference example. [Figure 7] FIG. 13 is a graph showing the change over time in the proportion of larval forms in another example. [Figure 8] FIG. 13 is a graph showing the change in food intake over time and the total amount in other examples and a reference example. [Figure 9] FIG. 1 illustrates an apparatus for treating plastic-containing material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the present disclosure will be described in detail with reference to embodiments. Note that the present disclosure is not limited to the following embodiments.

[0023] When plastic-containing materials are treated by feeding on lepidopteran larvae, the larvae stop feeding on the plastic-containing materials when they pupate. Therefore, if the period during which the larvae form is maintained can be extended, it is expected that the amount of plastic eaten by the larvae can be increased. The present disclosure includes a method for increasing the amount of plastic eaten by the larvae.

[0024] In this embodiment, the "plastic-containing material" may be a material made of plastic, or may include both plastic materials and materials other than plastic. In this embodiment, the larvae include larvae immediately after hatching to the final instar, regardless of the instar, unless otherwise specified. In this embodiment, "raising" includes feeding the larvae with the plastic-containing material and raising them. In this embodiment, the "treatment of the plastic-containing material" includes decomposition of the plastic-containing material (hereinafter also referred to as the treated object or treated plastic) using organisms such as larvae. The treatment of the plastic-containing material also includes breaking at least one bond in the plastic. The method for breaking the bond may be hydrolysis or oxidation-reduction, or other methods.

[0025] <Method for processing plastic-containing materials> The method for treating plastic-containing materials in this embodiment will be described below. The method for treating plastic-containing materials in this embodiment is characterized by comprising an introduction step of introducing lepidopteran insect larvae and plastic-containing materials into a rearing space, an adjustment step of adjusting at least the occupancy rate of the plastic-containing materials in the rearing space, and a feeding step of feeding the plastic-containing materials to the lepidopteran insect larvae in the rearing space.

[0026] In the method for treating plastic-containing materials according to the present embodiment, the types of plastics contained in the plastic-containing materials to be treated include those containing any of a C-C single bond, a C=C double bond, an ester bond, and an amide bond in at least a part of the plastic structure. For example, polyesters such as polyethylene terephthalate (PET), polybutylene phthalate (PBT), and polylactic acid (PLA), polyolefins such as polyethylene and polypropylene, polystyrene, polyamide, and paraffin can be mentioned.

[0027] In the method for treating plastic-containing materials of the present embodiment, the plastic-containing material to be treated is not limited to one type of plastic, and may contain multiple different types of plastics. In other words, as long as it contains at least one type of plastic among those listed above, it may be a composite material with different plastics.

[0028] The plastic-containing material to be treated may also be a composite material containing materials other than plastic, such as paper, cloth, metal, etc. For example, it may be a packaging container in which a plastic spout is connected to a paper packaging container body.

[0029] The plastic-containing material to be treated by the method for treating a plastic-containing material of the present embodiment may be a laminate. Specifically, the plastic-containing material may be a laminate material of plastic and paper, a laminate material of plastic and metal, or a retort pouch for food in which polyethylene terephthalate (PET), aluminum foil, and polypropylene are laminated.

[0030] In the method for treating plastic-containing materials according to the present embodiment, the plastic-containing materials to be treated may be in various forms, such as cups, pouches, bottles, caps, pellets, films, powders, particles, slurries, fibers, or capsules.

[0031] The plastic-containing material in this embodiment may be one having organic waste such as vegetable waste, animal waste, food residue, vegetable waste, processed food residue, soybean pulp, wheat straw, wood chips, rice husks, etc., or inorganic waste such as soil, sludge, cinders, soot, slag, glass waste, ceramic waste, concrete waste, rubble, etc. attached thereto. For example, it may be one having dirt derived from food that has not been washed attached thereto.

[0032] In this embodiment, the lepidopteran insect larvae (hereinafter also simply referred to as "larvae") are not particularly limited as long as they are larvae that can feed on the plastic-containing material. Specific examples include the larvae of Galleria mellonella, the larvae of the Pale Vellus mellonella, the larvae of the Lesser Vellus mellonella, and the larvae of the Indian Meal Moth.

[0033] In this embodiment, the term "galleria mellonella" refers to an organism of the family Pyralidae of the order Lepidoptera. The term "pallidum moth" refers to an organism of the family Pyralidae of the order Lepidoptera. The term "small wax moth" refers to an organism of the family Pyralidae of the order Lepidoptera. The term "Achroia grisella" refers to an organism of the family Pyralidae of the order Lepidoptera. The term "indian meal moth" refers to an organism of the family Pyralidae of the order Lepidoptera.

[0034] (Input process) In the method for treating plastic-containing materials according to the present embodiment, in the introduction step, the larvae of the above-mentioned lepidopteran insect are introduced into the breeding space. The breeding space is not particularly limited as long as it is a space capable of accommodating larvae. Specific examples of the breeding space include a breeding tank made of transparent plastic or glass, or a metal mesh storage tank, which can accommodate larvae and be observed from the outside. The breeding space may be appropriately divided by a partition plate or the like so that, for example, multiple larvae can be accommodated in isolation. Also, multiple larvae may be accommodated in the breeding space without being isolated.

[0035] The method of introducing larvae into the rearing space is not particularly limited as long as the larvae can be accommodated from the outside to the inside of the rearing space. Specifically, the larvae may be accommodated in the rearing space by an artificial method, for example, the larvae may be moved from the outside to the inside of the rearing space using a tool such as tweezers. The larvae may also be moved into the rearing space by a mechanical method such as a belt conveyor. The timing of introducing the larvae into the rearing space may be such that the larvae are supplied intermittently or automatically.

[0036] In the introduction process, the plastic-containing material is introduced into the rearing space. As a result, the larvae in the rearing space can ingest the plastic-containing material. There is no particular restriction on the order of introduction, and the larvae and the plastic-containing material may be introduced at the same time, or the timing of introducing the two into the rearing space may be different. As described above, the rearing space may have a partition using a board or the like, as long as the larvae can ingest the plastic-containing material.

[0037] In the feeding step in this embodiment, materials that do not contain plastic, for example, paper or metal that has not been surface-treated with plastic (paper packaging materials, metal packaging materials, etc.) may be fed.

[0038] In this embodiment, from the viewpoint of continuing the treatment of the plastic-containing material, it is preferable that the environment of the larvae after being introduced into the rearing space is maintained in an environment suitable for growth. For example, if the temperature is extremely high or low, the speed at which the larvae eat or consume the plastic-containing material will decrease. Therefore, it is preferable that the rearing temperature of the larvae be maintained between 15°C and 35°C.

[0039] There is no particular restriction on the humidity, but from the viewpoint of cost and the like, it is preferable that the humidity of the larvae's environment be maintained within the range of 20 to 80%.

[0040] (adjustment process) The adjustment process in this embodiment is a process of adjusting the occupancy rate of the plastic-containing material in the rearing space. That is, after the above-mentioned introduction process, at least the larvae and the plastic-containing material are contained in the rearing space, and the larvae are able to eat the plastic-containing material. Here, a certain proportion of the rearing space is occupied by the larvae and the plastic-containing material. This embodiment is characterized in that at least the occupancy rate of the plastic-containing material in the rearing space is adjusted.

[0041] Here, the above-mentioned "occupancy rate" is defined as the degree to which the plastic-containing material occupies the rearing space. Specifically, when the volume of the rearing space is 1000 cm 3 and the total volume of plastic-containing materials in the enclosure is 100 cm 3 In this case, the occupancy rate of the plastic-containing material can be said to be 10%. There is no particular limitation on the method for measuring the occupancy rate, but for example, the volume ratio obtained by dividing the volume of the plastic-containing material by the volume of the rearing space can be used as the occupancy rate. Note that, for example, when the shape of the plastic-containing material is a film, the volume of the plastic-containing material can be calculated from its length, width and thickness. The occupancy rate can also be obtained by pouring the plastic-containing material into a rearing space filled with water until it is full, and measuring the amount of water overflowing from the rearing space.

[0042] Moreover, "adjusting the occupancy rate" includes determining the occupancy rate. Specifically, it includes determining the amount of plastic-containing material to be introduced into the rearing space for the purpose of having the larvae eat the plastic-containing material. More specifically, it includes determining the amount of plastic-containing material to be introduced into the rearing space so that the amount of food eaten by the larvae increases or so that the larvae continue to eat for a predetermined period of time or more. Furthermore, in this embodiment, "adjusting the occupancy rate" includes changing the occupancy rate. That is, in this embodiment, "adjusting the occupancy rate" includes increasing or decreasing the occupancy rate. For example, when the volume of the rearing space is 1000 cm, 3 The amount of plastic-containing materials in the enclosure was measured by dividing the total by 100 cm 3 From 150cm 3 When the occupancy rate is increased to 10%, it can be said that the occupancy rate has been adjusted from 10% to 15%. Methods for increasing the occupancy rate include a method for introducing or replenishing plastic-containing materials into the rearing space. Methods for decreasing the occupancy rate include a method for extracting (removing) plastic-containing materials present in the rearing space or for feeding them to the larvae.

[0043] In this embodiment, the above-mentioned adjustment of the occupancy rate may be performed at least once at the same time as the introduction step or at any timing after the introduction step. That is, in this embodiment, the amount of plastic-containing material in the rearing space may be determined and introduced at the stage of introducing the larvae into the rearing space, and the plastic-containing material may not be replenished in the rearing space thereafter. Alternatively, in order to maintain or change the occupancy rate at the time of the introduction step, the plastic-containing material may be replenished or removed from the rearing space during the rearing period.

[0044] In addition, the adjustment process in this embodiment may be a process of adjusting the occupancy rate to a predetermined numerical range. More specifically, the occupancy rate of the plastic-containing material in the rearing space is preferably adjusted to be more than 1.09% from the viewpoint of the feeding amount of the larvae.

[0045] Furthermore, in this embodiment, the adjustment process may be a process of adjusting the occupancy rate to a predetermined numerical range according to the type of plastic-containing material. Specifically, the adjustment process may be a process of adjusting the occupancy rate so that the larvae's feeding amount is a predetermined amount or more based on data of the occupancy rate according to the type of plastic-containing material and the feeding amount of the larvae obtained in advance. As an example, when the plastic contained in the plastic-containing material is polyolefin, the occupancy rate may be adjusted to 2.0 to 8.0%. Also, when the plastic contained in the plastic-containing material is polyester, the occupancy rate may be adjusted to 1.2 to 4.0%. In this way, by adjusting the occupancy rate according to the type of plastic, it is possible to improve the feeding amount of the plastic-containing material by the larvae. Also, it is possible to lengthen the period during which the larvae's form is maintained, and it is possible to lengthen the feeding period of the plastic-containing material by the larvae.

[0046] In this embodiment, it is sufficient to adjust the occupancy rate of at least the plastic-containing material among the larvae and the plastic-containing material contained in the rearing space, and it is not essential to adjust the occupancy rate of the larvae in the rearing space. In other words, if the larvae are sufficiently small relative to the rearing space, the volume of the larvae can be ignored as an error, or the volume of the larvae can be set to zero.

[0047] On the other hand, when the occupancy rate of the larvae in the rearing space is also taken into consideration, there is no particular limitation on the method of acquiring the occupancy rate of the larvae, and a known method can be applied. For example, the volume of the larvae may be acquired using three-dimensional measurement by a camera or the like, and reflected in the occupancy rate. Alternatively, the volume of the larvae according to the number of days of growth after hatching may be stored in a database, and the database may be reflected in the occupancy rate of the larvae. The time point of acquiring the occupancy rate of the larvae may be any timing, or the occupancy rate may be acquired at multiple points in time according to the growth. For example, the initial volume of the larvae at the start of rearing may be measured and used as the occupancy rate of the larvae. In addition, the volume of the larvae growing daily may be measured in real time, and the change may be reflected in the occupancy rate.

[0048] In the adjustment process of this embodiment, the occupancy rate of the plastic-containing material can be indirectly adjusted by adjusting the non-occupancy rate in the rearing space. Specifically, the occupancy rate can be indirectly acquired by calculating the percentage of the rearing space occupied by the area not occupied by the plastic-containing material and the larvae (also called "non-occupied space") (also called "non-occupancy rate"). There is no particular restriction on the method of acquiring the non-occupancy rate, and known methods can be applied. For example, the volume of the area not occupied by the plastic-containing material and the larvae can be acquired by known three-dimensional measurement or the like.

[0049] (Feeding process) The method for treating plastic-containing materials in this embodiment includes a step of feeding the plastic-containing materials to larvae in a rearing space (feeding step). In general, the above-mentioned types of lepidopteran larvae are known to feed on a specific type of plastic.

[0050] There is no particular limit to the period during which the larvae are fed the plastic-containing material, and the plastic-containing material may be fed during the entire period from immediately after hatching to the final instar larvae, or may be fed during a specific period, for example, only during the final instar larvae. In addition, during the period during which the larvae are fed the plastic-containing material, the larvae may be fed only the plastic-containing material, or may be fed other materials (e.g., beeswax, wheat bran, honey, vegetable waste, etc.) in addition to the plastic-containing material.

[0051] The period during which the larvae are allowed to feed on the plastic-containing material may be changed depending on the rearing temperature of the larvae. That is, it is known that the period until the larvae become pupae varies depending on the rearing temperature. For example, when the rearing temperature of the larvae is about 30°C, the period from immediately after hatching to the final instar larvae is about 4 weeks, but when the rearing temperature is about 15°C or lower, the period from immediately after hatching to the final instar larvae may be about 5 months.

[0052] Therefore, for example, the temperature at which the larvae are reared may be set to 25°C or higher, and the period during which the larvae are allowed to feed on the plastic-containing material may be set to 1 to 4 weeks, and the period during which the larvae are allowed to feed on the plastic-containing material may be varied depending on the rearing temperature of the larvae.

[0053] The rearing temperature may be changed for each stage of rearing of the larvae from immediately after hatching to the final stage. In this case, when a plurality of larvae are present in the plastic processing device, the rearing temperature may be set to the rearing temperature corresponding to the most prevalent larvae among the immediately after hatching to the final stage.

[0054] As described above, the method for processing plastic-containing materials of this embodiment includes the above-mentioned feeding process, adjustment process, and feeding process, thereby making it possible to optimize the amount of plastic-containing materials processed using larvae.

[0055] <Processing equipment for plastic-containing materials> Next, the plastic-containing material processing device 100 of this embodiment will be described. As shown in Fig. 9, the plastic-containing material processing device 100 of this embodiment is characterized by including a breeding tank 10 capable of housing and raising lepidopteran insect larvae, and an adjustment device 20 capable of at least adjusting the occupancy rate of the plastic-containing material housed in the breeding tank and ingested by the larvae. The processing device 100 of this embodiment is an apparatus capable of realizing the above-mentioned plastic-containing material processing method. Therefore, detailed explanations of common terms will be omitted.

[0056] (Breeding tank 10) The breeding tank 10 is not particularly limited as long as it can accommodate and breed lepidopteran larvae. For example, it can be a transparent plastic or glass breeding tank or a metal mesh tank that can accommodate larvae and be observed from the outside. The breeding tank can be appropriately divided by a partition plate or the like so that multiple larvae can be isolated and housed. It can also be one that can accommodate multiple larvae without isolating them.

[0057] (Adjustment device 20) The adjustment device 20 of this embodiment is required to be able to at least adjust the occupancy rate of the plastic-containing material in the breeding tank 10. For example, lepidopteran insect larvae and plastic-containing material are both housed in the breeding tank. The lepidopteran insect larvae feed on the plastic-containing material and grow, eventually pupating into adults. In this process, as disclosed in the above-mentioned method for treating plastic-containing material, the occupancy rate in the breeding tank can be adjusted to increase the feeding rate of the larvae.

[0058] The adjusting device 20 of this embodiment is not particularly limited as long as it can control the occupancy rate in the breeding tank. As an example, the adjusting device 20 may be configured to include, for example, a known camera 11 capable of capturing an image of the inside of the breeding tank 10, a first conveyor 12 capable of putting the above-mentioned larvae into the breeding tank 10 or extracting them from the breeding tank 10, a second conveyor 13 capable of carrying the plastic-containing material P into the breeding tank 10 or carrying it out from the breeding tank 10, and a control device 50 capable of controlling them. The specific configuration of the first conveyor 12 and the second conveyor 13 is not particularly limited, and examples thereof include known conveying means such as known belt conveyors and robot arms capable of six-axis control.

[0059] In this case, a specific method for adjusting the occupancy rate using the adjustment device 20 can be performed as follows. First, the occupancy rate at any time in the breeding tank 10 (current occupancy rate) is acquired by the camera 11. The acquired current occupancy rate is compared with an ideal occupancy rate at which a desired feeding amount can be obtained. This ideal occupancy rate can be stored in advance in a storage device (not shown). Then, if the current occupancy rate is lower than the ideal occupancy rate, the control device 50 can perform a process of replenishing the breeding tank 10 with plastic-containing material P via the second conveyor 13 (plastic charging device).

[0060] Alternatively, as another example of a method for adjusting the occupancy rate, if the current occupancy rate is higher than the ideal occupancy rate, the control device 50 can perform a process of replenishing larvae W in the breeding tank 10 via the first conveyor 12 (larvae introduction device).

[0061] Such an adjustment of the occupancy rate may be performed at any timing according to the growth rate of the larvae in the breeding tank. In addition, by constantly observing the inside of the breeding tank 10 with the camera 11, the occupancy rate may be maintained within a predetermined range, or the feeding amount of the larvae may be automatically replenished with the plastic-containing material P and the larvae W in order to maintain the occupancy rate within a predetermined range.

[0062] Furthermore, the adjustment device 20 may include an agitator, a vibrator, or the like (not shown) for varying the positions of the plastic-containing material P and the larvae W contained in the breeding tank. These devices can also be used to adjust the occupancy rate by moving the positions of the larvae W in the breeding tank. EXAMPLES

[0063] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples.

[0064] (How to calculate the share) The occupancy rate of the plastic-containing material in the rearing space was calculated as follows: The volume of the film used in each example was calculated from the size and thickness of the film, and the volume was divided by the volume of the rearing space of the rearing bottle used in each example to obtain a volume ratio, and the occupancy rate of the plastic-containing material in the rearing space was calculated.

[0065] Occupancy rate (%) = film volume (cm 3 ) / Volume of rearing space (cm 3 )×100(%)

[0066] Example 1 As samples, ten sheets of polyethylene non-oriented film (thickness 40 μm) and a breeding bottle (volume 48 cm 3 Ten glass containers (100 mm diameter) were prepared for each rearing bottle. One Galleria mellonella larva (approximately 200 mg in weight) and one of the above samples were placed in each rearing bottle. When placing the larvae, the sample was placed around them.

[0067] The occupancy rate of the above sample in the rearing bottle was 2.33%. This occupancy rate does not include the volume of the larvae. The rearing bottle containing the larvae and sample was kept in a room at 35°C for 11 days for rearing. During the rearing period, the sample was removed once a day to measure the sample weight (described below), and any cocoons attached to the sample were removed at that time. In addition, feces in the rearing bottle were removed at the same time, and the sample after measurement was returned to the rearing bottle. In addition, no sample was replenished during the rearing period.

[0068] At each point after the start of the rearing period, 4 days, 7 days, and 11 days, it was recorded whether or not the larvae were still surviving while maintaining their larval form. Specifically, pupation, death, and near-pupation (appearances of larval form but barely moving, and a form that seems to be in the process of transitioning to pupation) were judged to be "not in the larval form." As a result, after 4 days, 4 out of 10 rearing bottles were still surviving while maintaining their larval form (40% larval form). After 7 days, 2 out of 10 rearing bottles were still surviving while maintaining their larval form (20% larval form). After 11 days, none of the 10 rearing bottles were still surviving while maintaining their larval form (0% larval form).

[0069] Furthermore, the amount of food consumed by the larvae was determined after 4 days, 7 days, and 11 days. The amount of food consumed was determined by removing only the sample from the rearing bottle and measuring its weight. If the sample contained cocoons excreted by the larvae, the cocoons were removed with tweezers before measuring the weight of the sample. The amount of weight loss of the sample in each of the 10 rearing bottles was determined, and the average value excluding the maximum and minimum values ​​was taken as the amount of food consumed by the larvae.

[0070] The results of the change in feeding amount over time obtained in Example 1 are shown in Table 1. The change in the proportion of larval forms over time is shown in FIG. 1, and the total feeding amount is shown in FIG.

[0071] Example 2 The same procedure was followed as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 3.30%. The change over time in the proportion of larval forms was not recorded, and the feeding amount was measured in the same manner as in Example 1. The results of the change over time in feeding amount obtained in Example 1 are shown in Table 1, and the total feeding amount is shown in Figure 2.

[0072] Example 3 The same procedure was followed as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 3.85%. The change over time in the proportion of larval forms was not recorded, and the feeding amount was measured in the same manner as in Example 1. The results of the change over time in feeding amount obtained in Example 1 are shown in Table 1, and the total feeding amount is shown in Figure 2.

[0073] Example 4 The same procedure was followed as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 4.67%. The change over time in the proportion of larval forms was not recorded, and the feeding amount was measured in the same manner as in Example 1. The results of the change over time in feeding amount obtained in Example 1 are shown in Table 1, and the total feeding amount is shown in Figure 2.

[0074] Example 5 The larvae were reared in the same manner as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 5.60%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 7 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 70%). After 11 days, 6 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 60%). The results of the change over time in the amount of food intake obtained are shown in Table 1. The change over time in the proportion of larval form is shown in FIG. 1, and the total amount of food intake is shown in FIG. 2.

[0075] Example 6 The larvae were reared in the same manner as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 6.60%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 90%). After 11 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 90%). The results of the change over time in the amount of food intake obtained are shown in Table 1. The change over time in the proportion of larval form is shown in FIG. 1, and the total amount of food intake is shown in FIG. 2.

[0076] (Reference example 1) The same procedure was followed as in Example 1, except that the occupancy rate of the above sample in the rearing bottle was set to 1.65%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 1. The results of the change in feeding amount over time obtained in Reference Example 1 are shown in Table 1, and the total feeding amount is shown in Figure 2.

[0077] [Table 1]

[0078] According to the above-mentioned Examples 1 to 6 and Reference Example 1, it was confirmed that the feeding amount of the larvae was increased by adjusting the occupancy rate. Also, according to the above-mentioned Examples 1 to 6, it was confirmed that the feeding of the plastic-containing material by the larvae continued even after 4 days from the start of rearing. Furthermore, as shown in FIG. 1, it was confirmed that the period during which the larval morphology was maintained changed depending on the occupancy rate.

[0079] Example 7 The volume of the breeding bottle as the breeding space is 252 cm 3The larvae were reared in the same manner as in Example 1, except that the occupancy rate of the sample in the rearing bottle was set to 2.22%, and the change over time in the proportion of larval forms and the amount of food intake were recorded. Regarding the change over time in the proportion of larval forms, after 4 days, 2 out of 10 rearing bottles were still surviving while maintaining the larval form (proportion of larval forms: 20%). Furthermore, after 7 days and 11 days, none of the 10 rearing bottles were still surviving while maintaining the larval form (proportion of larval forms: 0%). The results of the change over time in the amount of food intake are shown in Table 2. The change over time in the proportion of larval forms is shown in FIG. 3, and the total amount of food intake is shown in FIG. 4.

[0080] Example 8 The same procedure was followed as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 3.14%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 7. The results of the change in feeding amount over time obtained in Example 8 are shown in Table 2, and the total feeding amount is shown in Figure 4.

[0081] Example 9 The same procedure was followed as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 3.67%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 7. The results of the change in feeding amount over time obtained in Example 9 are shown in Table 2, and the total feeding amount is shown in Figure 4.

[0082] Example 10 The same procedure was followed as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 4.44%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 7. The results of the change in feeding amount over time obtained in Example 10 are shown in Table 2, and the total feeding amount is shown in Figure 4.

[0083] Example 11 The larvae were reared in the same manner as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 5.33%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 8 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 80%). After 11 days, 6 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 60%). The results of the change over time in the amount of food intake obtained are shown in Table 2. The change over time in the proportion of larval form is shown in FIG. 3, and the total amount of food intake is shown in FIG. 4.

[0084] Example 12 The larvae were reared in the same manner as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 6.29%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 90%). After 11 days, 8 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 80%). The results of the change over time in the amount of food intake obtained are shown in Table 2. The change over time in the proportion of larval form is shown in FIG. 3, and the total amount of food intake is shown in FIG. 4.

[0085] (Reference example 2) The same procedure was followed as in Example 7, except that the occupancy rate of the above sample in the rearing bottle was set to 1.57%. The change over time in the proportion of larval forms was not recorded, and the feeding amount was measured in the same manner as in Example 7. The results of the change over time in feeding amount obtained in Reference Example 2 are shown in Table 2, and the total feeding amount is shown in FIG.

[0086] [Table 2]

[0087] In comparison with Examples 1 to 6 and Reference Example 1, Examples 7 to 12 and Reference Example 2 above confirmed that even when the size of the rearing space was different, the amount of plastic-containing material eaten by the larvae changed by adjusting the occupancy rate. Specifically, Examples 7 to 11 and Reference Example 2 confirmed that the amount of food eaten by the larvae increased as the occupancy rate increased. Furthermore, Examples 8 to 12 confirmed that the larvae continued to eat the plastic-containing material even after four days from the start of rearing. Furthermore, as shown in FIG. 3, it was confirmed that the period during which the larvae's morphology was maintained changed depending on the occupancy rate.

[0088] (Example 13) A polypropylene unstretched film (thickness 40 μm) was used as the sample in the rearing bottle, and the occupancy rate of the sample in the rearing bottle was set to 2.47%, but rearing was performed in the same manner as in Example 1. The change in the proportion of larval form over time was not recorded, and the amount of food intake was measured in the same manner as in Example 1. The results of the change in the amount of food intake over time obtained in Example 13 are shown in Table 3, and the total amount of food intake is shown in FIG. 6.

[0089] Example 14 The same procedure was followed as in Example 13, except that the occupancy rate of the above sample in the rearing bottle was set to 3.50%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 13. The results of the change in feeding amount over time obtained in Example 14 are shown in Table 3, and the total feeding amount is shown in Figure 6.

[0090] Example 15 The same procedure was followed as in Example 13, except that the occupancy rate of the above sample in the rearing bottle was set to 4.10%. The change in the proportion of larval forms over time was not recorded, and the amount of food intake was measured in the same manner as in Example 13. The results of the change in the amount of food intake over time obtained in Example 15 are shown in Table 3, and the total amount of food intake is shown in Figure 6.

[0091] Example 16 The larvae were reared in the same manner as in Example 13, except that the occupancy rate of the above sample in the rearing bottle was set to 4.90%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 11 days, 8 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 80%). The results of the change over time in the amount of food intake obtained are shown in Table 3. The change over time in the proportion of larval form is shown in FIG. 5, and the total amount of food intake is shown in FIG. 6.

[0092] (Example 17) The larvae were reared in the same manner as in Example 13, except that the occupancy rate of the above sample in the rearing bottle was set to 7.00%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 11 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 90%). The results of the change over time in the amount of food intake obtained are shown in Table 3. The change over time in the proportion of larval form is shown in FIG. 5, and the total amount of food intake is shown in FIG. 6.

[0093] (Reference example 3) The larvae were reared in the same manner as in Example 13, except that the occupancy rate of the above sample in the rearing bottle was set to 1.75%, and the change over time in the proportion of larval forms and the amount of food intake was recorded. Regarding the change over time in the proportion of larval forms, after 4 days, 5 out of 10 rearing bottles were still alive and maintained their larval forms (proportion of larval forms: 50%). In addition, after 7 days and 11 days, 0 out of 10 rearing bottles were still alive and maintained their larval forms (proportion of larval forms: 0%). The results of the change over time in the amount of food intake are shown in Table 3. The change over time in the proportion of larval forms is shown in FIG. 5, and the total amount of food intake is shown in FIG. 6.

[0094] [Table 3]

[0095] According to the above Examples 13 to 17 and Reference Example 3, in comparison with Examples 1 to 12 and Reference Examples 1 to 2, it was confirmed that even in the case of different plastic-containing materials, the amount of food eaten by the larvae changes by adjusting the occupancy rate. More specifically, it was confirmed that the amount of food eaten by the larvae increases as the occupancy rate increases. Furthermore, in comparison with Examples 13 to 17 and Reference Example 3, it was confirmed that when the occupancy rate is a predetermined value or more, the larvae continue to eat the plastic-containing material even after four days from the start of rearing. Furthermore, as shown in FIG. 5, it was confirmed that the period during which the larvae's morphology is maintained changes depending on the occupancy rate.

[0096] Moreover, according to Examples 1 to 17, it was confirmed that the feeding amount of the larvae increases when the occupancy rate is in the range of 2.0 to 8.0%, more preferably 3.0 to 7.0%.

[0097] (Example 18) A polyethylene terephthalate unstretched film (thickness 17 μm) was used as the sample in the rearing bottle, and the occupancy rate of the sample in the rearing bottle was 1.49%, but rearing was performed in the same manner as in Example 1. The change in the proportion of larval forms over time was not recorded, and the amount of food intake was measured in the same manner as in Example 1. The results of the change in the amount of food intake over time obtained in Example 18 are shown in Table 4, and the total amount of food intake is shown in FIG.

[0098] (Example 19) The same procedure was followed as in Example 18, except that the occupancy rate of the above sample in the rearing bottle was set to 2.18%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 18. The results of the change in feeding amount over time obtained in Example 19 are shown in Table 4, and the total feeding amount is shown in Figure 8.

[0099] (Example 20) The larvae were reared in the same manner as in Example 18, except that the occupancy rate of the above sample in the rearing bottle was set to 2.48%, and the change over time in the proportion of larval forms and the amount of food intake was recorded. Regarding the change over time in the proportion of larval forms, after 4 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 90%). After 7 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 90%). After 11 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 90%). The results of the change over time in the amount of food intake obtained are shown in Table 4. The change over time in the proportion of larval forms is shown in FIG. 7, and the total amount of food intake is shown in FIG. 8.

[0100] Example 21 The same procedure as in Example 18 was repeated, except that the occupancy rate of the above sample in the rearing bottle was set to 3.67%. The change in the proportion of larval forms over time was not recorded, and the feeding amount was measured in the same manner as in Example 18. The results of the change in feeding amount over time obtained in Example 21 are shown in Table 4, and the total feeding amount is shown in Figure 8.

[0101] (Reference example 4) The larvae were reared in the same manner as in Example 18, except that the occupancy rate of the above sample in the rearing bottle was set to 1.09%, and the change over time in the proportion of larval form and the amount of food intake was recorded. Regarding the change over time in the proportion of larval form, after 4 days, 10 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 100%). After 7 days, 2 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval form was 20%). After 11 days, 1 out of 10 rearing bottles was alive while maintaining the larval form (the proportion of larval form was 10%). The results of the change over time in the amount of food intake obtained are shown in Table 4. The change over time in the proportion of larval form is shown in FIG. 7, and the total amount of food intake is shown in FIG. 8.

[0102] (Reference example 5) The same procedure was followed as in Example 18, except that the occupancy rate of the above sample in the rearing bottle was set to 4.36%. The change over time in the proportion of larval forms was not recorded, and the feeding amount was measured in the same manner as in Example 18. The results of the change over time in feeding amount obtained in Reference Example 5 are shown in Table 4, and the total feeding amount is shown in FIG.

[0103] (Reference example 6) The larvae were reared in the same manner as in Example 18, except that the occupancy rate of the above sample in the rearing bottle was set to 6.25%, and the change over time in the proportion of larval forms and the amount of food intake was recorded. Regarding the change over time in the proportion of larval forms, after 4 days, 9 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 90%). After 7 days, 6 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 60%). After 11 days, 5 out of 10 rearing bottles were alive while maintaining the larval form (the proportion of larval forms was 50%). The results of the change over time in the amount of food intake obtained are shown in Table 4. The change over time in the proportion of larval forms is shown in FIG. 7, and the total amount of food intake is shown in FIG. 8.

[0104] [Table 4]

[0105] According to the above Examples 18 to 21 and Reference Examples 4 to 6, it was confirmed that the amount of food eaten by the larvae changes by adjusting the occupancy rate, even when the type of plastic is different (for example, when polyester is used), in comparison with Examples 1 to 17 and Reference Examples 1 to 3. More specifically, it was confirmed that the amount of food eaten by the larvae changes depending on the occupancy rate. When Examples 18 to 21 are compared with Reference Examples 4 to 6, it was confirmed that the amount of food eaten by the larvae increases when the occupancy rate is in the range of 1.2 to 4.0%, particularly in the range of 1.49 to 3.67%. In addition, it was confirmed that when the occupancy rate is within a predetermined range, the larvae continue to eat the plastic-containing material even after 4 days from the start of rearing. Furthermore, as shown in FIG. 7, it was confirmed that the period during which the larvae form is maintained changes depending on the occupancy rate.

[0106] Based on the results of the above examples, it can be easily understood by those skilled in the art that the period during which the larvae form is maintained and the amount of food intake can change in the same manner as in the examples, not only depending on the occupancy rate in the rearing space, but also depending on the "non-occupancy rate" of the area other than the area occupied by the larvae and the plastic-containing material. Furthermore, even when multiple larvae are housed in the rearing space, the period during which the larvae form is maintained and the amount of food intake can be controlled in the same manner. Furthermore, it is possible to improve the amount of food intake of the larvae and maintain a high state of food intake regardless of the size of the rearing space.

[0107] According to the present disclosure, it is expected that the efficiency of processing plastic-containing materials by larvae can be improved. [Industrial Applicability]

[0108] The invention can be used in a method for treating various plastic-containing materials under appropriate conditions according to the type and state of the plastic-containing materials. [Explanation of symbols]

[0109] 100: Processing equipment for plastic-containing materials 10: Breeding tank 20: Adjustment device 11: Camera 12: First conveyor 13: Second conveyor 50: Control device

Claims

1. An introduction step of introducing lepidopteran insect larvae and plastic-containing materials into a rearing space; an adjusting step of adjusting an occupancy rate of at least the plastic-containing material in the rearing space; a feeding step of feeding the larvae with the plastic-containing material in the rearing space; 1. A method for treating plastic-containing material, comprising:

2. The method for treating a plastic-containing material according to claim 1 , wherein in the adjusting step, the occupancy rate is adjusted to be greater than 1.09%.

3. 3. The method for treating a plastic-containing material according to claim 1 or 2, wherein the plastic contained in the plastic-containing material is selected from the group consisting of polyester, polyolefin, polystyrene, polyamide, and paraffin.

4. the plastic contained in the plastic-containing material is a polyolefin; The method for treating a plastic-containing material according to claim 1 or 2, wherein in the adjusting step, the occupancy rate is adjusted to be 2.0 to 8.0%.

5. the plastic contained in the plastic-containing material is polyester; The method for treating a plastic-containing material according to claim 1 or 2, wherein in the adjusting step, the occupancy rate is adjusted to be 1.2 to 4.0%.

6. 3. A method for treating plastic-containing material according to claim 1 or claim 2, wherein the plastic-containing material comprises two or more types of plastic.

7. 3. The method for treating a plastic-containing material according to claim 1 or 2, wherein the plastic-containing material is a laminate.

8. 3. The method for treating plastic-containing materials according to claim 1 or 2, wherein the form of the plastic-containing material is at least one of a film, a cup, a pouch, a pellet, a bottle, a powder, a fiber, or a capsule.

9. 3. A method for treating plastic-containing material according to claim 1 or claim 2, wherein the larvae are Galleria mellonella larvae.

10. a breeding tank capable of housing and breeding lepidopteran insect larvae; The present invention is characterized in that it includes an adjustment device capable of at least adjusting the occupancy rate of the plastic-containing material contained in the breeding tank and consumed by the larvae. Equipment for processing plastic-containing materials.

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