Method for decomposing polyurethane foam and apparatus for decomposing polyurethane foam

Abstract

To provide a method for decomposing polyurethane foam, making it possible to produce polyols with stable quality.SOLUTION: A method for decomposing polyurethane foam includes the steps of: agitating a pulverized product 11 of polyurethane foam without heating to apply a decomposer 13 to the pulverized product 11; and heating the pulverized product 11 to which the decomposer 13 has been applied, to obtain polyols.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present disclosure relates to a method for decomposing a polyurethane foam and an apparatus for decomposing a polyurethane foam.

Background Art

[0002] Patent Document 1 discloses a method for decomposing a rigid urethane resin. This method has a decomposition treatment step in which a rigid urethane resin and an amine compound as a decomposing agent are charged into an extruder and heated to 140 to 300°C to advance the decomposition of the urethane bond of the rigid urethane resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using an extruder to mix a polyurethane foam and a decomposing agent and decompose the polyurethane foam, it is difficult to control the mixing state of the polyurethane foam and the decomposing agent and the decomposition reaction. For this reason, there is a problem that the quality of the obtained decomposition product is unstable, such as the unreacted polyurethane foam being forcibly discharged from the extruder.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a method for decomposing a polyurethane foam and an apparatus for decomposing a polyurethane foam that can obtain a polyol with stable quality. The present disclosure can be realized in the following forms.

Means for Solving the Problems

[0007] According to this disclosure, a polyol of stable quality can be obtained. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram illustrates the process of applying a decomposition agent to the pulverized material. [Figure 2] This is a schematic cross-sectional view showing an example of pulverized material coated with a decomposition agent. [Figure 3] This is a cross-sectional view showing the reaction vessel. [Figure 4] This diagram illustrates the process of heating pulverized material coated with a decomposition agent to obtain a polyol. [Modes for carrying out the invention]

[0009] Herein lies a preferred example of this disclosure. The heating of the pulverized material is carried out using a reaction vessel. The reaction vessel has an inlet for introducing the pulverized material coated with the decomposition agent, and an outlet for discharging the polyol. A method for decomposing polyurethane foam, comprising heating the pulverized material introduced into the reaction vessel near the discharge port. The heating of the pulverized material is carried out using a reaction vessel. The reaction vessel has an inlet for introducing the pulverized material coated with the decomposition agent, and an outlet for discharging the polyol. A method for decomposing polyurethane foam, wherein the discharge port is opened at the lower end of the reaction vessel. A method for decomposing polyurethane foam, wherein the inner surface of the reaction vessel has an inclined surface that slopes downward toward the discharge port. The heating of the pulverized material is carried out using a reaction vessel. The reaction vessel has an inlet for introducing the pulverized material coated with the decomposition agent, and an outlet for discharging the polyol. A method for decomposing polyurethane foam, comprising applying force toward the discharge port side to the pulverized material introduced into the reaction vessel without applying shear force. • A stirrer for stirring the pulverized polyurethane foam, A coating device for applying a decomposition agent to the pulverized material in the agitator, The system comprises a reaction vessel for heating the pulverized material to which the decomposition agent has been applied, and decomposing it into a polyol, The aforementioned agitator does not have a heat source. The reaction vessel has a heat source for heating the pulverized material to which the decomposition agent has been applied, and is a decomposition apparatus for polyurethane foam.

[0010] The disclosure is described in detail below. In this specification, when a numerical range is indicated using "-", it includes both the lower and upper limits unless otherwise specified. For example, the expression "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less".

[0011] The polyurethane foam decomposition method of this embodiment comprises the steps of stirring the pulverized polyurethane foam 11 without heating and applying a decomposition agent 13 to the pulverized material 11, and heating the pulverized material 11 to which the decomposition agent 13 has been applied to obtain a polyol 15.

[0012] The polyurethane foam may be flexible polyurethane foam, semi-rigid polyurethane foam, or rigid polyurethane foam. The polyurethane foam may have an open-cell structure or a closed-cell structure. As the crushed polyurethane foam 11, for example, scraps discharged during the manufacturing process of polyurethane foam, or used polyurethane foam that is scheduled to be discarded can be crushed and used. Alternatively, the crushed polyurethane foam 11 may be the waste or scraps of polyurethane foam discharged during the manufacturing process of polyurethane foam.

[0013] The decomposition agent 13 is not particularly limited as long as it chemically decomposes and liquefies the urethane bonds, but compounds having hydroxyl groups or amine compounds are preferred in terms of reactivity and cost. Examples of compounds containing hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentadiol, 1,6-hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, and polyethylene glycol. These compounds containing hydroxyl groups can be used individually or in combination of two or more. Among these, dipropylene glycol and 1,4-butanediol are preferred. Examples of the amine compound include ethylenediamine, tetramethylenediamine, hexamethylenediamine, propanediamine, 2-ethylhexylamine, isopropanolamine, 2-(2-aminoethylamino)ethanol, 2-amino-2-hydroxymethyl-1,3-propanediol, ethylaminoethanol, aminobutanol, n-propylamine, di-n-propylamine, n-amylamine, isobutylamine, methyldiethylamine, monoethanolamine, diethanolamine, triethanolamine, cyclohexylamine, piperazine, piperidine, aniline, toluidine, benzylamine, phenylenediamine, xylylenediamine, chloroaniline, pyridine, picoline, N-methylmorpholine, ethylmorpholine, pyrazole, etc. These amine compounds can be used alone or in combination of two or more. Among these, diethanolamine and triethanolamine are preferred.

[0014] The addition amount of the decomposing agent 13 is preferably 5 parts by mass or more and 30 parts by mass or less, more preferably 10 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyurethane foam.

[0015] In the decomposition reaction using the decomposing agent 13, a decomposition catalyst can be further added as necessary to increase the reaction rate. As the catalyst to be added, those used in the production of urethane foam are preferred. For example, triethylamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropane 1,3-diamine, N,N,N',N'-tetramethylhexane 1,6-diamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyldipropylenetriamine, tetramethylguanidine, triethylenediamine, N,N'-dimethylpiperazine, N-methyl, N'-(2-dimethylamino)ethylpiperazine, N-methylmorpholine, N-(N',N'-dimethylaminoethyl)-morpholine, 1,2-dimethylimidazole, hexamethylenetetramine, dimethylaminoethanol, dimethylaminoethoxyethanol, N,N,N'-trimethylaminoethylethanolamine, N-methyl-N'-(2-hydroxyethyl)-piperazine, N-(2-hydroxyethyl)morpholine, bis(2-dimethylaminoethyl)ether, ethylene glycol bis(3-dimethyl)-aminopropyl ether, diazabicycloundecene, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutylindium maleate, dioctyltin mercaptide, dioctyltin thiocarboxylate, lead octoate, zinc octoate, calcium octoate, potassium acetate, potassium octoate, etc. Among these, triethylenediamine, diazabicycloundecene, potassium acetate, and potassium octoate are preferred.

[0016] <( The addition amount of the catalyst is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the decomposer.

[0017] <( It should be noted that there is a possible error in the original text where "<( " and "<( " seem to be incorrect tags. They are presented as such in the translation to maintain consistency with the original.Here, an example of a suitable decomposition apparatus 20 for realizing the above-described manufacturing method will be explained using Figures 1 and 3. The decomposition apparatus 20 comprises a stirrer 21, a coating device 27, and a reaction vessel 30. Figure 1 shows the stirrer 21 and the coating device 27, and Figure 3 shows the reaction vessel 30. When describing the decomposition apparatus 20, the vertically upward and downward directions in the installed state of the decomposition apparatus 20 will be referred to as "upper" and "lower."

[0018] The agitator 21 is a device for stirring the pulverized polyurethane foam 11. As shown in Figure 1, the agitator 21 has a stirring tank 23 and a stirring blade 25 (an example of a power unit) for stirring the pulverized material 11 in the stirring tank 23. The stirring blade 25 rotates around an axis that extends in a substantially horizontal direction. The agitator 21 is a rotary type. With a rotary type agitator 21, the decomposition agent 13 can be suitably applied to the entire surface of the pulverized polyurethane foam 11.

[0019] The agitator 21 does not have a heat source. That is, the agitator 21 has at least a stirring tank 23 and a power unit (stirring blade 25), but does not have a heat source to heat the pulverized material 11 in the stirring tank 23. Note that "the agitator 21 does not have a heat source" means that it does not have a heat source such as a heater, but it may have a power unit or the like that generates heat when driven.

[0020] The coating device 27 is a device that applies the decomposing agent 13 to the pulverized material 11 in the agitator 21. The coating device 27 uses a spray application method for the decomposing agent 13. In Figure 1, only the nozzle of the coating device 27 is shown. The agitator 21 and the coating device 27 are used to obtain the pulverized material 11 to which the decomposing agent 13 has been applied. Hereinafter, the pulverized material 11 to which the decomposing agent 13 has been applied will also be simply referred to as the composite material 10.

[0021] The reaction vessel 30 is a vessel for heating pulverized material 11 (composite material 10) coated with a decomposition agent 13 to decompose it into polyol 15. As shown in Figure 3, the reaction vessel 30 has an inlet 31 for introducing the composite material 10 and an outlet 32 ​​for discharging the polyol 15. The outlet 32 ​​is open at the lower end of the reaction vessel 30. The outlet 32 ​​is provided with a screen 33 that prevents undecomposed pulverized material 11 from passing through, but allows liquid decomposition products containing polyol 15 to pass through. An inclined surface 35A is formed on the inner surface of the reaction vessel 30, sloping downward toward the outlet 32. The inclined surface 35A is provided around the outlet 32 ​​and has a shape corresponding to the side of a frustum.

[0022] The inner and outer diameters of the reaction vessel 30 are smaller on the discharge port 32 side than on the inlet port 31 side. More specifically, the reaction vessel 30 has a first cylindrical section 34, a reduced diameter section 35, and a second cylindrical section 36 arranged coaxially from top to bottom. The first cylindrical section 34 is cylindrical in shape and extends along the vertical direction. An inlet port 31 is provided at the top of the first cylindrical section 34. The reduced diameter section 35 is continuous with the lower end of the first cylindrical section 34, and its inner diameter decreases as it goes downwards. An inclined surface 35A is formed on the inner surface of the reduced diameter section 35. The second cylindrical section 36 is continuous with the lower end of the reduced diameter section 35, and is cylindrical in shape with smaller inner and outer diameters than the first cylindrical section 34. The lower end of the second cylindrical section 36 opens downwards. The discharge port 32 is provided at the lower end of the second cylindrical section 36. Thus, the reaction vessel 30 has a space directly above the discharge port 32 for accommodating the composite material 10 and for carrying out the decomposition reaction of the polyurethane foam.

[0023] The reaction vessel 30 has a heater 38 (an example of a heat source) for heating the composite material 10. The reaction vessel 30 is made of metal, for example. The heater 38 is, for example, an electric heating wire and is located on the outside of the reaction vessel 30. The heater 38 heats the composite material 10 inside the reaction vessel 30 through the reaction vessel 30. The heater 38 is located in the part where the inclined surface 35A is formed (the reduced diameter part 35). The heater 38 is located in the part where the discharge port 32 is provided (the second cylindrical part 36). On the other hand, the heater 38 is not located in the part where the inlet port 31 is provided (the first cylindrical part 34). In other words, the reaction vessel 30 is configured such that the decomposition reaction mainly takes place in the part on the discharge port 32 side, and the composite material 10 is stored in the part on the inlet port 31 side.

[0024] The method for transporting the composite material 10 in the agitator 21 to the inlet 31 of the reaction vessel 30 is not particularly limited. In this embodiment, since heating is not performed in the agitator 21, stickiness of the composite material 10 due to decomposition products can be suppressed. For this reason, handling of the composite material 10 in the agitator 21 is easy, and a general-purpose transport method can be appropriately adopted. For example, the composite material 10 in the agitator 21 may be transported by air to the inlet 31 of the reaction vessel 30. Alternatively, an inlet may be provided on the side of the reaction vessel, and the composite material 10 in the agitator 21 may be pushed into the inlet using a screw conveyor or the like.

[0025] Next, an example of a method for decomposing polyurethane foam will be described with reference to Figures 1 and 4. The step of stirring the pulverized polyurethane foam 11 without heating and applying the decomposing agent 13 to the pulverized foam 11 (hereinafter also referred to as the application step) is performed using a stirrer 21 and a coating device 27, as shown in Figure 1. In the application step, the pulverized foam 11 is stirred while being rolled. In the application step, the decomposing agent 13 is spray-applied to the stirred pulverized foam 11 from a position above and at a distance. From the viewpoint of suppressing the decomposition reaction of polyurethane foam, it is preferable that the temperature of the pulverized foam 11 in the stirrer 21 is between 0°C and 60°C. In the application step, pulverized foam 11 (composite material 10) to which the decomposing agent 13 has been applied is obtained.

[0026] The composition of the composite 10 obtained in the coating process is not particularly limited. The composite 10 can take various forms depending on the size of the pulverized material 11, the cellular structure of the polyurethane foam, etc. The composite 10 has the decomposing agent 13 attached to at least the surface of the pulverized material 11. Figure 2 shows an example of a composite 10 in which the decomposing agent 13 is coated onto pulverized material 11 having an open-cell structure. A portion of the decomposing agent 13 permeates the surface layer of the pulverized material 11. For example, the amount of decomposing agent 13 per unit volume contained in the pulverized material 11 is greater on the surface layer of the pulverized material 11 than inside the pulverized material 11.

[0027] The step of heating the composite material 10 to obtain polyol 15 (hereinafter also referred to as the heating step) is carried out using a reaction vessel 30, as shown in Figure 4. In the heating step, the pulverized material 11 introduced into the reaction vessel 30 is heated near the discharge port 32. "Near the discharge port 32" refers to at least one of the part where the discharge port 32 is provided (second cylindrical part 36) and the part where an inclined surface 35A that descends toward the discharge port 32 is formed (reduced diameter part 35). Furthermore, in the heating step, the pulverized material 11 may also be heated in the part from the discharge port 32 up to the height that the pulverized material 11 reaches during the decomposition reaction of polyurethane foam (for example, up to the height of H1 / H0 = 2 / 3 described later). It is preferable not to heat the pulverized material 11 above the height that the pulverized material 11 reaches in the heating step. With the above configuration, the decomposition reaction of polyurethane foam can be promoted on the discharge port 32 side of the reaction vessel 30, while the decomposition reaction of polyurethane foam can be suppressed on the input port 31 side. Therefore, it is possible to suppress the unintended decomposition reaction of polyurethane foam when the pulverized material 11 is introduced (before the pulverized material 11 is compressed), which would cause decomposition products to adhere to the area around the input port 31 and to the components used to compress the pulverized material 11. In the decomposition process of polyurethane foam, in order to obtain polyols of stable quality, it is effective to clean the reaction vessel 30 for each type of polyurethane foam being processed. As described above, by separating the heated and unheated parts of the reaction vessel 30, the adhesion of decomposition products can be limited, and the cleaning of the reaction vessel 30 can be made easier. In addition, during the decomposition reaction of polyurethane foam (for example, when the pulverized material 11 is compressed), energy efficiency in the heating process can be improved by not unnecessarily heating parts where there is no pulverized material 11.

[0028] The heating temperature of the composite material 10 is not particularly limited. Preferably, the heating temperature of the composite material 10 is 150°C to 250°C, and more preferably 180°C to 230°C. The heating temperature of the composite material 10 is the temperature of the hottest part of the composite material 10 in the reaction vessel 30. In this embodiment, since the composite material 10 is heated by direct contact with the reaction vessel 30 heated by the heater 38, the set temperature of the heater 38 may be considered as the heating temperature of the composite material 10.

[0029] In the heating process, a force is applied to the composite material 10 introduced into the reaction vessel 30 toward the discharge port 32 without applying a shear force. "Without applying a shear force" means that no shear force is applied when the material is extruded by the extruder. A means of applying a force without applying a shear force is to apply a force so that the pulverized material 11 is compressed in one direction without breaking. Specifically, an example is to apply a load to the composite material 10 using a weight 39.

[0030] The height H1 of the compressed composite material 10 is not particularly limited. Preferably, the height H1 of the compressed composite material 10 satisfies the following formula (1), where H0 is the height when the composite material 10 is filled into a roughly cylindrical container by gravity, and H1 is the height after the composite material 10 is compressed in the direction of the cylindrical axis of the roughly cylindrical container. 1 / 30 ≤ H1 / H0 ≤ 2 / 3 ···(1) The H1 / H0 value may vary depending on the porosity of the polyurethane foam, the size of the crushed material 11, etc. The H1 / H0 value can be adjusted by changing the magnitude of the force applied to the composite material 10. In the reaction vessel 30 shown in Figures 3 and 4, the volumes of the reduced-diameter section 35 and the second cylindrical section 36 are sufficiently smaller than the volume of the first cylindrical section 34. Therefore, the heights H0 and H1 are defined by considering the first cylindrical section 34 as a roughly cylindrical container.

[0031] More specifically, the heating process is carried out as follows: A load is applied to the composite material 10 (pulverized material 11) in the reaction vessel 30 toward the discharge port 32. The pulverized material 11 is filled into the second cylindrical section 36 and compressed by being pressed against the inclined surface 35A of the diameter-reducing section 35. The heater 38 is heated, and the pulverized material 11 is heated through the second cylindrical section 36 and the diameter-reducing section 35, which are heated by the heater 38. At this time, the pulverized material 11 may also be heated in the first cylindrical section 34. By preheating the pulverized material 11 in the first cylindrical section 34 and then heating the preheated pulverized material 11 while pressing it against the diameter-reducing section 35, the pulverized material 11 can be heated efficiently. The pulverized material 11 is gradually decomposed from the surface layer to which the decomposition agent 13 is attached, and liquid decomposition products are generated. The liquid decomposition products include polyol 15 derived from the raw materials of polyurethane foam, amine components 16 derived from the raw material isocyanate, etc. The liquid decomposition product flows along the inclined surface 35A of the reduced diameter section 35 and the inner surface of the second cylindrical section 36 toward the outlet 32, passes through the screen 33, and is discharged from the outlet 32. The liquid decomposition product is recovered as appropriate. For example, a recovery container 40 is placed below the outlet 32 ​​to recover the decomposition product that has flowed down from the outlet 32 ​​into the recovery container 40. From the recovered decomposition product, the polyol 15 is purified by a known method to obtain recycled polyol 15. In addition to polyol 15, various other components may be purified from the recovered decomposition product to obtain recycled raw materials.

[0032] Next, the effects of this embodiment will be described. The polyurethane foam decomposition method and decomposition apparatus 20 of this embodiment apply the decomposition agent 13 without heating, and then heats the pulverized material 11 to which the decomposition agent 13 has been applied to obtain polyol 15. Therefore, by optimizing the application process and the heating process, a decomposition product of stable quality can be obtained. Furthermore, since the polyurethane foam pulverized material 11 is stirred without heating and the decomposition agent 13 is applied to the pulverized material 11, the decomposition agent 13 can be applied uniformly and at a high concentration to the surface of the pulverized material 11. Due to its own heat insulation properties, the surface layer of the polyurethane foam pulverized material 11 is more easily heated than the interior. According to this embodiment, the pulverized material 11 can be decomposed sequentially from the surface layer, which has a high concentration of decomposition agent 13 and is easily heated, resulting in high decomposition efficiency.

[0033] Conventionally, extruders or kneaders, which have been widely used for the decomposition of polyurethane foam, are relatively expensive, and removing decomposition products from within the apparatus is complicated. On the other hand, the agitator 21 of this embodiment can be made more inexpensive and simpler than an extruder or kneader, and since no heating is performed, decomposition products are less likely to adhere to it. Furthermore, the reaction vessel 30 can also be made more inexpensive and simpler than an extruder or kneader, and the removal of decomposition products from within the apparatus is also easier.

[0034] Furthermore, in this embodiment, the pulverized material 11 introduced into the reaction vessel 30 is heated near the discharge port 32. With this configuration, the generated decomposition products can be easily discharged sequentially from the discharge port 32. In addition, if the inner diameter of the reaction vessel 30 is smaller on the discharge port 32 side than on the inlet port 31 side, the surface of the pulverized material 11 coated with the decomposition agent 13 can be efficiently heated by pressing the pulverized material 11 against the inner surface on the discharge port 32 side while heating it. Moreover, the decomposition efficiency of the polyurethane foam can be improved by preheating the pulverized material 11 on the inlet port 31 side of the reaction vessel 30 and then heating the preheated pulverized material 11 on the discharge port 32 side.

[0035] Furthermore, in this embodiment, the discharge port 32 of the reaction vessel 30 is open at the lower end of the reaction vessel 30. With this configuration, the generated liquid decomposition product can be easily separated from the undecomposed pulverized material 11 by allowing it to flow down from the discharge port 32. For this reason, compared to a configuration that forcibly pushes out the contents, such as an extruder, it is less likely that the undecomposed pulverized material 11 will be discharged.

[0036] Furthermore, in this embodiment, an inclined surface 35A is formed on the inner surface of the reaction vessel 30, which slopes downward toward the discharge port 32. With this configuration, the pulverized material 11 inside the reaction vessel 30 can be easily sent toward the discharge port 32 along the inclined surface 35A. In addition, the generated liquid decomposition product can be flowed down toward the discharge port 32 along the inclined surface 35A and discharged from the discharge port 32 in a suitable manner. Moreover, by heating the pulverized material 11 while pressing it against the inclined surface 35A, the surface of the pulverized material 11 to which the decomposition agent 13 is applied can be efficiently heated, thereby improving the decomposition efficiency of the polyurethane foam.

[0037] Furthermore, in this embodiment, force is applied to the pulverized material 11 introduced into the reaction vessel 30 toward the discharge port 32 without applying shear force. With this configuration, the pulverized material 11 can be compressed while being sent toward the discharge port 32. As a result, the amount of pulverized material 11 that can be introduced can be increased compared to the case where the pulverized material 11 is uncompressed. Also, since the pulverized material 11 is less likely to break, fracture surfaces that are not coated with the decomposition agent 13 are less likely to appear on the surface of the pulverized material 11. As a result, the pulverized material 11 can be efficiently decomposed by sequentially heating the surface of the pulverized material 11 from the surface coated with the decomposition agent 13. In addition, by applying force toward the discharge port 32, the surface of the pulverized material 11 can be brought into close contact with the inner surface of the reaction vessel 30, and heat can be efficiently transferred from the reaction vessel 30 to the pulverized material 11.

[0038] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings, and the technical scope of this disclosure also includes, for example, the following embodiments. (1) The stirring method of the agitator is not limited. The agitator may be a rotary type in which the stirring tank rotates, or a reciprocating type in which the stirring tank moves back and forth. (2) The method of applying the decomposing agent using the application device is not limited. The application device may be a method other than spraying the decomposing agent, such as a method in which the decomposing agent is directly added without being atomized, mixed with the pulverized material, and then applied. (3) The heating method in the reaction vessel is not limited. The heater may be a heating element or a heating medium. The heat source may be located inside the reaction vessel as well as outside. The heating of the composite material (pulverized material) may be carried out throughout the entire reaction vessel. (4) The configuration of the reaction vessel can be changed as appropriate. The reaction vessel may be a cylindrical vessel installed with its axial direction horizontal. The outlet may be an opening on the side of the reaction vessel. The reaction vessel may not have a second cylindrical section, and the outlet may be provided at the lower end of the reduced diameter section. (5) The means of applying force without applying shear force are not limited. The means of applying force without applying shear force may be means of mechanically pressing the composite material, etc. Furthermore, the decomposition apparatus may not have means of applying force to the pulverized material introduced into the reaction vessel, and the pulverized material may be moved toward the discharge port by the weight of the pulverized material itself or by the flow of the decomposition products.

[0039] This disclosure is not limited to the embodiments detailed above, and various modifications or alterations are possible. [Explanation of Symbols]

[0040] 10…Composite 11... Crushed material 13… Decomposing agent 15…Polyol 16…Amine components 20... Disassembly and disassembly processing equipment 21…Agitator 23...Stirring tank 25...Agitation blade 27…Coating device 30…Reaction vessel 31...Inlet 32…Discharge port 33…Screen 34...First cylindrical part 35...Reduced diameter part 35A…Slanted surface 36...Second cylindrical part 38… Heater 39... Weight 40…Collection containers

Claims

1. A step of stirring the pulverized polyurethane foam without heating it, and applying a decomposition agent to the pulverized material, A method for decomposing polyurethane foam, comprising the steps of heating the pulverized material to which the decomposing agent has been applied to obtain a polyol, The heating of the pulverized material is carried out using a reaction vessel. The reaction vessel has an inlet for introducing the pulverized material coated with the decomposition agent, and an outlet for discharging the polyol. A method for decomposing polyurethane foam, comprising applying force toward the discharge port side to the pulverized material introduced into the reaction vessel without applying shear force.

2. A stirrer for agitating the pulverized polyurethane foam, A coating device for applying a decomposition agent to the pulverized material in the agitator, The system comprises a reaction vessel for heating the pulverized material to which the decomposition agent has been applied, and decomposing it into a polyol, The aforementioned agitator does not have a heat source. The reaction vessel has an inlet for introducing the pulverized material coated with the decomposition agent, an outlet for discharging the polyol, and a heat source for heating the pulverized material coated with the decomposition agent. A polyurethane foam decomposition apparatus configured to apply force toward the discharge port side to the pulverized material introduced into the reaction vessel without applying shear force.

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