Recovery method, and method of producing regenerated polyol

Abstract

To provide one or more techniques of a technique for selectively chemically decomposing a polyurethane part of a composite material to recover a polyester part and a technique for selectively chemically decomposing the polyurethane part of the composite material to produce a regenerated polyol.SOLUTION: There is provided a recovery method for recovering a polyester part from a composite material including the polyester part and a polyurethane part, wherein the recovery method comprises: selectively chemically decomposing the polyurethane part of the composite material using one or more decomposition agents selected from the following (1), (2), and (3): (1) The decomposing agent is a mixture of a heterocyclic compound having an amidine structure and a polyhydric alcohol. (2) The decomposing agent is a mixture of a heterocyclic compound having an amidine structure and a carboxylic acid having 4 to 10 carbon atoms. (3) The decomposing agent is a mixture of a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms and a compound having a triazole skeleton.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a recovery method and a method for producing recycled polyol. [Background technology]

[0002] Patent Document 1 describes a method for producing recycled polyol from polyurethane foam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-246568 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although the decomposition of polyurethane has been studied, the decomposition of composite materials having polyester and polyurethane parts has not been sufficiently studied. There is a demand for a technology for selectively chemically decomposing the polyurethane part of a composite material to recover the polyester part, and a technology for selectively chemically decomposing the polyurethane part of a composite material to produce recycled polyol.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide one or more of a technique for selectively chemically decomposing the polyurethane part of a composite material to recover a polyester part, and a technique for selectively chemically decomposing the polyurethane part of a composite material to produce a recycled polyol. The present disclosure can be realized in the following forms. [Means for solving the problem]

[0006] [1] A method for recovering a polyester portion from a composite material having a polyester portion and a polyurethane portion, comprising the steps of: A recovery method comprising selectively chemically decomposing the polyurethane portion of the composite material using one or more decomposing agents selected from the following (1), (2), and (3): (1) The decomposition agent comprises a heterocyclic compound having an amidine structure, and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less, The mass ratio of the heterocyclic compound to the polyhydric alcohol is 1:20-1:40. (2) The decomposition agent comprises a heterocyclic compound having an amidine structure, A mixture of carboxylic acids having 4 to 10 carbon atoms, The mass ratio of the heterocyclic compound to the carboxylic acid is 1:10-1:50. (3) The decomposition agent comprises a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms; A mixture with a compound having a triazole skeleton, The mass ratio of the metal salt to the compound having a triazole skeleton is 1:0.7 to 1:10.

[0007] [2] A method for producing a recycled polyol by decomposing a composite material having a polyester portion and a polyurethane portion and recovering the resulting polyol, A method for producing a recycled polyol, comprising selectively chemically decomposing the polyurethane portion of the composite material using one or more decomposing agents selected from the following (1), (2), and (3): (1) The decomposition agent comprises a heterocyclic compound having an amidine structure, and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less, The mass ratio of the heterocyclic compound to the polyhydric alcohol is 1:20-1:40. (2) The decomposition agent comprises a heterocyclic compound having an amidine structure, A mixture of carboxylic acids having 4 to 10 carbon atoms, The mass ratio of the heterocyclic compound to the carboxylic acid is 1:10-1:50. (3) The decomposition agent comprises a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms; A mixture with a compound having a triazole skeleton, The mass ratio of the metal salt to the compound having a triazole skeleton is 1:0.7 to 1:10.

[0008] In this disclosure, "selectively chemically decomposing the polyurethane portion" means either of the following [1] or [2]. [1] The polyurethane portion is chemically decomposed, but the polyester portion is not chemically decomposed. [2] The polyurethane portion is chemically decomposed, and only a portion of the polyester portion is chemically decomposed. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide one or more of the following technologies: a technology for selectively chemically decomposing the polyurethane portion of a composite material to recover the polyester portion; and a technology for selectively chemically decomposing the polyurethane portion of a composite material to produce recycled polyol. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present disclosure will be described in detail below. In this specification, when a numerical range is described using "-", the lower limit and the upper limit are included unless otherwise specified. For example, the description "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". In this specification, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0011] 1. Method for recovering polyester parts The recovery method of the present embodiment is a method for recovering a polyester portion from a composite material having a polyester portion and a polyurethane portion, in which the polyurethane portion of the composite material is selectively chemically decomposed using one or more decomposing agents selected from the following (1), (2), and (3). (1) The decomposition agent comprises a heterocyclic compound having an amidine structure, and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less, The mass ratio of the heterocyclic compound to the polyhydric alcohol is 1:20-1:40. (2) The decomposition agent comprises a heterocyclic compound having an amidine structure, A mixture of carboxylic acids having 4 to 10 carbon atoms, The mass ratio of the heterocyclic compound to the carboxylic acid is 1:10-1:50. (3) The decomposition agent comprises a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms; A mixture with a compound having a triazole skeleton, The mass ratio of the metal salt to the compound having a triazole skeleton is 1:0.7 to 1:10.

[0012] 1.1 Composite materials The composite material includes a polyester part and a polyurethane part. The shape of the composite material and the configuration of the polyester part and the polyurethane part are not particularly limited. For example, the composite material may be configured such that a layered polyester part is provided on the surface of the polyurethane part, or may be configured such that a layered polyurethane part is provided on the surface of the polyester part. The composite material may be a laminate including a layered polyester part and a layered polyurethane part. When the polyester part and / or the polyurethane part are configured in layers, it is difficult to separate the polyester part and the polyurethane part by means of cutting or the like, and the technology of the present disclosure is particularly effective. The composite material may be, for example, offcuts generated during the manufacturing process of a product, or a post-consumer product destined for disposal.

[0013] The mass ratio of the polyester part to the polyurethane part in the composite material is not particularly limited. From the viewpoint of recycling efficiency of the polyurethane part or obtaining a sufficient amount of recycled polyol, the mass ratio of the polyester part to the polyurethane part (polyester part: polyurethane part) is preferably 1:99-80:20, more preferably 2:98-60:40, and further preferably 5:95-30:70.

[0014] The polyester constituting the polyester portion is preferably at least one selected from the group consisting of aromatic polyesters and aliphatic polyesters. The aromatic polyester is preferably at least one selected from the group consisting of polyethylene terephthalate (PET), polypropylene terephthalate (PPT), and polybutylene terephthalate (PBT).

[0015] The polyurethane constituting the polyurethane portion may be foamed or non-foamed. The polyurethane foam may be any of soft polyurethane foam, semi-rigid polyurethane foam, and rigid polyurethane foam. Examples of polyurethane include polyether-based polyurethane made from polyether polyol, polyester-based polyurethane made from polyester polyol, and polycarbonate-based polyurethane. Among these, polyether-based polyurethane is preferred because it can be used to obtain a recycled polyol that is the same as the polyol derived from the raw material.

[0016] 1.2 Decomposition Agent In the recovery method of the present embodiment, one or more decomposing agents selected from the above (1), (2), and (3) are used to selectively chemically decompose the polyurethane part of the composite material. The present inventors have conducted extensive research and have newly discovered that the polyurethane part of the composite material can be selectively chemically decomposed when the decomposing agents (1)-(3) are used, leading to the development of the technology of the present disclosure. Here, the decomposing agent that decomposes the polyurethane part has a property that acts on the decomposition reaction of the urethane bond. Examples of reactions that are decomposition reactions of the urethane bond include acidolysis, hydrolysis, aminolysis, and glycolysis. In these reactions, the decomposing agent may act as a decomposition catalyst, or may itself act as a reactant.

[0017] (1) Mixture of heterocyclic compound having amidine structure and polyhydric alcohol The heterocyclic compound having an amidine structure is not particularly limited. Here, the amidine structure is R 1 -C(=NR 2 )-NR 3 R 4 (wherein R 1 ,R 2 ,R 3 ,R 4 are the same or different and represent a hydrogen atom or a hydrocarbon group.) Heterocyclic compounds having an amidine structure are considered to have a catalytic effect in the hydrolysis of urethane bonds. It is also considered that heterocyclic compounds having an amidine structure have a hydrolysis effect on ester bonds. In this embodiment, it is presumed that the polyurethane portion can be suitably and selectively chemically decomposed by using a mixture of a heterocyclic compound having an amidine structure and another compound.

[0018] Examples of heterocyclic compounds having an amidine structure include diazabicyclononene derivatives and diazabicycloundecene derivatives. Among these, diazabicycloundecene (1,8-diazabicyclo[5.4.0]undecene-7, hereinafter also referred to as "DBU"), diazabicyclononene (1,5-diazabicyclo[4.3.0]nonene-5, hereinafter also referred to as "DBN"), and at least one selected from the group consisting of these derivatives are preferred.

[0019] Examples of diazabicycloundecene (DBU) and derivatives thereof include DBU, DBU carbonate, DBU carboxylate, DBU phenol salt, and DBU thiol salt. Examples of diazabicyclononene (DBN) and derivatives thereof include DBN, DBN carbonate, DBN carboxylate, DBN phenol salt, and DBN thiol salt.

[0020] The polyhydric alcohol is at least one selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less. The polyhydric alcohol preferably has a molecular weight smaller than that of the polyol obtained as a partial decomposition product of polyurethane. It is believed that the polyhydric alcohol can act as a reactant in the glycolysis of urethane bonds.

[0021] The combination of the heterocyclic compound having an amidine structure and the above polyhydric alcohol is not particularly limited. For example, the combination of the heterocyclic compound having an amidine structure and the above polyhydric alcohol is a combination of diazabicycloundecene and ethylene glycol.

[0022] In order to selectively chemically decompose the polyurethane portion of the composite material, the mass ratio of the heterocyclic compound to the polyhydric alcohol in the decomposition agent (1) is 1:20-1:40, and preferably 1:25-1:35.

[0023] The amount of the decomposition agent (1) added is not particularly limited. The amount of the decomposition agent (1) added is preferably 0.1 parts by mass or more and 200 parts by mass or less, more preferably 0.5 parts by mass or more and 100 parts by mass or less, and even more preferably 1 part by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the composite material. The amount of the decomposition agent (1) added is the total amount of the mixture of the heterocyclic compound having an amidine structure and the polyhydric alcohol.

[0024] (2) Mixture of heterocyclic compounds having an amidine structure and carboxylic acids having 4-10 carbon atoms The heterocyclic compound having an amidine structure is not particularly limited, and the heterocyclic compound having an amidine structure described above in “(1) Mixture of a heterocyclic compound having an amidine structure and a polyhydric alcohol” can be used.

[0025] The carboxylic acid having 4 to 10 carbon atoms is not particularly limited. The carboxylic acid may be a monocarboxylic acid, a dicarboxylic acid, or a tricarboxylic acid. The carboxylic acid having 4 to 10 carbon atoms may be one or more selected from the group consisting of adipic acid, citric acid, citric acid monohydrate, p-phenolsulfonic acid, phthalic anhydride, succinic anhydride, octanoic acid, and malic acid. It is considered that the above carboxylic acid can act as a reactant in the acidolysis of urethane bonds. In principle, it is considered that acidolysis does not decompose ester bonds, but decomposes only urethane bonds. Therefore, it is considered that carboxylic acids having 4 to 10 carbon atoms are particularly effective as a component of a decomposing agent that selectively chemically decomposes polyurethane parts.

[0026] The combination of the heterocyclic compound having an amidine structure and the above-mentioned carboxylic acid is not particularly limited. For example, the combination of the heterocyclic compound having an amidine structure and the above-mentioned carboxylic acid includes a combination of diazabicycloundecene and adipic acid.

[0027] In order to selectively chemically decompose the polyurethane portion of the composite material, the mass ratio of the heterocyclic compound to the adipic acid in the decomposition agent (2) is 1:10-1:50, and preferably 1:15-1:45.

[0028] The amount of the decomposition agent (2) added is not particularly limited. The amount of the decomposition agent (2) added is preferably 0.1 parts by mass or more and 200 parts by mass or less, more preferably 0.5 parts by mass or more and 100 parts by mass or less, and even more preferably 1 part by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the composite material. The amount of the decomposition agent (2) added is the total amount of the mixture of the heterocyclic compound having an amidine structure and the carboxylic acid having 4 to 10 carbon atoms.

[0029] (3) A mixture of a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms and a compound having a triazole skeleton. The metal salt is not particularly limited. Examples of the saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms include at least one selected from the group consisting of octylic acid, acetic acid, and 2-ethylhexanoic acid. Examples of the metal constituting the metal salt include alkali metals. Examples of the alkali metal include potassium, lithium, and sodium.

[0030] The metal salt may be, for example, one or more selected from the group consisting of potassium octoate, potassium acetate, sodium acetate, and potassium 2-ethylhexanoate.

[0031] The compound having a triazole skeleton is not particularly limited. The triazole skeleton may be a 1,2,3-triazole skeleton or a 1,2,4-triazole skeleton. Examples of the compound having a triazole skeleton include one or more selected from the group consisting of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear), benzotriazole, and 3-amino-1H-1,2,4-triazole. The 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) is a compound represented by the following formula (1). [ka]

[0032] The combination of the above-mentioned metal salt and the compound having a triazole skeleton is not particularly limited.The combination of the above-mentioned metal salt and the compound having a triazole skeleton can be, for example, the combination of potassium octylate and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear).

[0033] In order to selectively chemically decompose the polyurethane portion of the composite material, the mass ratio of the above-mentioned metal salt to the above-mentioned compound having a triazole skeleton in the above-mentioned (3) decomposition agent is 1:0.7-1:10, and preferably 1:0.7-1:5.

[0034] The amount of the decomposing agent (3) added is not particularly limited. The amount of the decomposing agent (3) added is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the composite material. The amount of the decomposing agent (3) added is the total amount of the mixture of the metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms and the compound having a triazole skeleton.

[0035] 1.3 An example of decomposition processing In the recovery method of this embodiment, the polyurethane part of the composite material is selectively chemically decomposed using one or more decomposing agents selected from the above (1), (2), and (3). The selective chemical decomposition of the polyurethane part is performed by subjecting the composite material to a decomposition treatment under conditions in which the polyurethane part is chemically decomposed and a part or all of the polyester part is not chemically decomposed. The polyurethane is decomposed into a polyol and an amine compound by the decomposition treatment. When the polyurethane part of the composite material is selectively chemically decomposed, a liquid decomposition product is usually obtained. The undecomposed polyester part is obtained in a state in which it remains in the liquid decomposition product. The undecomposed polyester part can be extracted from this liquid decomposition product to recover the polyester part.

[0036] In one example of a method for decomposing a composite material, the composite material and one or more decomposing agents selected from (1), (2), and (3) above are placed in a container and maintained at a predetermined treatment temperature. The treatment temperature is preferably 120°C or higher and 250°C or lower, more preferably 170°C or higher and 230°C or lower. The time for maintaining the predetermined treatment temperature can be appropriately set depending on the amount of the composite material, the amount of the decomposing agent, the treatment temperature, etc. Then, the liquid decomposition product is retained in the container, and the polyurethane part is further selectively chemically decomposed in the liquid decomposition product. After the decomposition of the polyurethane part, the polyester part is recovered. The polyester part can be recovered, for example, by filtering the decomposition product.

[0037] The decomposition liquid may be obtained in a single phase state, or may be obtained in a phase-separated state with an upper phase containing at least a polyol and a lower phase containing at least an amine compound. If the decomposition liquid is in a phase-separated state, it is preferable because it is easy to recover the polyol derived from the polyurethane part. In order to obtain the decomposition product of the polyurethane resin in a phase-separated state, the amount of the decomposition agent and the amount of the virgin polyol added optionally may be appropriately adjusted.

[0038] The use of the recovered polyester part is not particularly limited. The recovered polyester part may be recycled as it is, or may be used as a regenerated raw material. In addition, the recovered polyester part may be discarded as it is.

[0039] 2. Manufacturing method of recycled polyol The method for producing recycled polyol involves decomposing a composite material having a polyester portion and a polyurethane portion, and recovering the resulting polyol to produce recycled polyol. The method for producing recycled polyol involves selectively chemically decomposing the polyurethane portion of the composite material using one or more decomposing agents selected from the above (1), (2), and (3). In the method for producing recycled polyol, the explanations for the composite material, the decomposition agent, and an example of the decomposition treatment of the composite material in the section "1. Recovery method for recovering polyester part" in "1.1 Composite material," "1.2 Decomposition agent," and "1.3 Example of decomposition treatment" apply as is, and the description thereof will be omitted.

[0040] In the method for producing the recycled polyol, the composite material is decomposed as described above, and the obtained polyol is recovered. The recovered polyol can be purified by a known method or can be used as it is as the recycled polyol.

[0041] The method of recovering the polyol is not particularly limited. For example, the decomposition treatment liquid may be in a phase-separated state, and only the upper phase containing at least the polyol may be recovered. In this way, the amine compound and the like present in the lower phase can be suitably separated from the polyol.

[0042] 3. Effects of this embodiment The method for recovering the polyester portion and the method for producing the recycled polyol of this embodiment can directly decompose the composite material having the polyester portion and the polyurethane portion. Conventionally, a technique for decomposing polyurethane and a technique for decomposing polyester have been reported, but a technique for selectively chemically decomposing the polyurethane portion of the composite material is not known. If the polyester portion and the polyurethane portion are separated in advance by a means such as cutting, and then the polyurethane portion is decomposed, the separation of the polyester portion and the polyurethane portion is time-consuming. In addition, it is difficult to completely separate the polyester portion and the polyurethane portion. On the other hand, according to this embodiment, the time and effort required for the separation of the polyester portion and the polyurethane portion can be saved. EXAMPLES

[0043] 1. Screening of decomposition agents A laminate having a layered polyester portion and a layered polyurethane portion was prepared as a composite material having a polyester portion and a polyurethane portion. The laminate having a thickness of 2.5 mm was cut into a size of 30 mm x 30 mm to prepare a sample. <Composite material> Rogers Inoac PORON, product number SR-S, thickness 2.5mm Polyurethane section: Polyether polyurethane foam Polyester section: Polyethylene terephthalate sheet Polyurethane part: polyester part = 8:92 (mass ratio) The blend ratio of polyurethane raw materials and composite raw materials when the total is 100 parts by mass Polyol Polyether polyol 56 parts by mass Isocyanate MDI 22 parts by weight Other ingredients: 14 parts by weight

[0044] The decomposition agent shown in Table 1 was placed in an aluminum cup container, and the sample was placed with the polyester part facing up. The amount of decomposition agent was 50 parts by mass per 100 parts by mass of the sample. The container containing the decomposition agent and the sample was placed on a hot plate heated to 200°C and left to stand for 5 hours. After that, it was returned to room temperature, and the decomposition state of the sample was visually confirmed.

[0045] [Table 1]

[0046] 2. Results of decomposition agent screening The decomposition agents were visually evaluated according to the following criteria, and the results are shown in Table 1. <Degradability of polyurethane part> "Decompose": Some or all of the polyurethane part remains. "Does not decompose": All polyurethane parts remain. <Degradability of polyester part> "Decompose": Some or all of the polyester portion remains. "Does not decompose": The entire polyester portion remains. <Evaluation> "A": The decomposability of both the polyurethane portion and the polyester portion is "decomposable." "B": The decomposition property of the polyurethane portion is "decomposable", and the decomposition property of the polyester portion is "not decomposable". "C": Both the polyurethane part and the polyester part are not decomposable.

[0047] Among the decomposition agents listed in Table 1, diazabicycloundecene (DBU) and a salt of diazabicycloundecene (DBU-phenol salt) were found to be rated "A." DBU and DBU-phenol salt are examples of heterocyclic compounds having an amidine structure.

[0048] Of the decomposing agents listed in Table 1, it was found that dipropylene glycol was rated as "B". In addition, it was found that ethylene glycol, diethylene glycol, and polyethylene glycol with a number average molecular weight of 200 were rated as "C". Dipropylene glycol, ethylene glycol, diethylene glycol, and polyethylene glycol (Mn200) are examples of the above polyhydric alcohols.

[0049] Of the decomposition agents listed in Table 1, adipic acid, citric acid monohydrate, p-phenolsulfonic acid, phthalic anhydride, succinic anhydride, octanoic acid, and malic acid were found to be rated "B." Adipic acid, citric acid monohydrate, p-phenolsulfonic acid, phthalic anhydride, succinic anhydride, octanoic acid, and malic acid are examples of carboxylic acids with 4 to 10 carbon atoms.

[0050] Of the decomposing agents listed in Table 1, potassium octoate was found to be rated "A". In addition, bismuth carboxylate and zirconium octoate were found to be rated "B". Potassium octoate, bismuth carboxylate, and zirconium octoate are examples of metal salts of saturated or unsaturated carboxylic acids having 2 to 10 carbon atoms.

[0051] Among the decomposition agents listed in Table 1, benzotriazole, 3-amino-1H-1,2,4-triazole, and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) were found to be rated "B." Benzotriazole, 3-amino-1H-1,2,4-triazole, and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) are examples of compounds that have a triazole skeleton.

[0052] 3. Recovery of polyester parts and production of recycled polyol In this example, the same composite material as in "1. Screening of decomposition agents" was cut into a size of 40 mm x 40 mm to prepare a sample.

[0053] As examples and comparative examples of the decomposition agent (1), mixtures of the following components 1 and 2 were prepared. The mass ratios of the components were as shown in Table 2. Ingredient 1: DBU Component 2: Ethylene glycol

[0054] As an example of the decomposition agent (2), a mixture of the following components 1 and 2 was prepared. The mass ratio of each component was as shown in Table 2. Ingredient 1: DBU Ingredient 2: Adipic acid

[0055] As examples and comparative examples of the decomposition agent (3), mixtures of the following components 1 and 2 were prepared. The mass ratios of the components were as shown in Table 2. Ingredient 1: Potassium octylate Component 2: 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear)

[0056] The decomposition agents (1) to (3) shown in Table 2 and the sample were placed in a flask, and the temperature was raised to 210° C., followed by heating for 5 hours. The amount of each component relative to 100 parts by mass of the sample was as shown in Table 2. After heating, the temperature was returned to room temperature, and the decomposition product was filtered. The polyester portion was collected as the residue. In addition, a brown decomposition treatment liquid was collected as the filtrate.

[0057] [Table 2]

[0058] 4. Results of recovery of polyester parts and production of recycled polyol In the examples and comparative examples, when the polyester part could be recovered, it was judged as "passable," and when the polyester part could not be recovered, it was judged as "failed." The results are shown in Table 2.

[0059] In the case of the mixture of DBU and ethylene glycol as the decomposition agent (1), the result was "passable" when the mass ratio of DBU to ethylene glycol was 1:30. In the case of the mixture of DBU and adipic acid (decomposition agent (2)), the result was "passable" in all cases where the mass ratio of DBU to adipic acid was 1:20, 1:29, 1:40, or 3.3:66. In the case of a mixture of potassium octylate and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) as the decomposition agent (3), the result was "OK" when the mass ratio of potassium octylate to 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) was 1:2 or 1:1.

[0060] In addition, the decomposition treatment liquid of the examples that were judged to be "pass" contained polyol obtained by decomposing the polyurethane part. In other words, recycled polyol was produced as the decomposition treatment liquid.

[0061] 5. Effects of the embodiment According to the present embodiment, a technique for selectively chemically decomposing the polyurethane part of a composite material to recover the polyester part can be provided. Also, a technique for selectively chemically decomposing the polyurethane part of a composite material to produce a recycled polyol can be provided.

[0062] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible.

Claims

1. A method for recovering a polyester portion from a composite material having a polyester portion and a polyurethane portion, comprising the steps of: A recovery method comprising selectively chemically decomposing the polyurethane portion of the composite material using one or more decomposing agents selected from the following (1), (2), and (3): (1) The decomposition agent comprises a heterocyclic compound having an amidine structure, and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less, The mass ratio of the heterocyclic compound to the polyhydric alcohol is 1:20 to 1:

40. (2) The decomposition agent comprises a heterocyclic compound having an amidine structure, and a carboxylic acid having 4 to 10 carbon atoms, The mass ratio of the heterocyclic compound to the carboxylic acid is 1:10 to 1:

50. (3) The decomposition agent comprises a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms, A mixture with a compound having a triazole skeleton, The mass ratio of the metal salt to the compound having a triazole skeleton is 1:0.7 to 1:

10.

2. A method for producing a recycled polyol by decomposing a composite material having a polyester portion and a polyurethane portion and recovering the resulting polyol, comprising: A method for producing recycled polyol, comprising selectively chemically decomposing the polyurethane portion of the composite material using one or more decomposing agents selected from the following (1), (2), and (3): (1) The decomposition agent comprises a heterocyclic compound having an amidine structure, and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, polyethylene glycol having a molecular weight of 400 or less, propylene glycol, and polypropylene glycol having a molecular weight of 400 or less, The mass ratio of the heterocyclic compound to the polyhydric alcohol is 1:20 to 1:

40. (2) The decomposition agent comprises a heterocyclic compound having an amidine structure, and a carboxylic acid having 4 to 10 carbon atoms, The mass ratio of the heterocyclic compound to the carboxylic acid is 1:10 to 1:

50. (3) The decomposition agent comprises a metal salt of a saturated or unsaturated carboxylic acid having 2 to 10 carbon atoms, A mixture with a compound having a triazole skeleton, The mass ratio of the metal salt to the compound having a triazole skeleton is 1:0.7 to 1:10.

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