Method for producing recycled polyols

Abstract

This invention provides technology for utilizing by-product amine compounds resulting from the decomposition of polyurethane resins. [Solution] The method for producing recycled polyol involves reacting a polyurethane resin with a decomposition agent to separate it into a phase mainly composed of polyol and a phase mainly composed of an amine compound, reacting the amine compound with a carboxylic acid compound, recovering a composition containing the resulting reaction product, and adding a carboxylic acid and / or its anhydride having two or more carboxyl groups to the composition such that the ratio of the molar amount of hydroxyl groups and the total molar amount of amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a recycled polyol having amide bonds and ester bonds in its molecular chain.

Description

[Technical Field]

[0001] This disclosure relates to a method for producing recycled polyols. [Background technology]

[0002] Patent Document 1 describes a method for treating decomposed and recovered polyols containing amines, obtained by decomposing polyurethane resin, by adding an isocyanate compound. It states that the isocyanate group of the isocyanate compound selectively reacts with the amino group of the amines to produce polyurea, thereby inactivating the amines. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2001-081234 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Patent Document 1 describes the inactivation of amines in recovered polyols with isocyanate compounds, but it does not consider the use of by-product amine compounds.

[0005] This disclosure is made in view of the above circumstances and aims to provide technology for the utilization of by-product amine compounds associated with the decomposition of polyurethane resins. This disclosure can be implemented in the following forms. [Means for solving the problem]

[0006] By reacting a decomposition agent with polyurethane resin, the resin is separated into a phase mainly composed of polyols and a phase mainly composed of amine compounds. The amine compound is reacted with a carboxylic acid compound, and the resulting reaction product is collected to obtain a composition containing the product. A method for producing a regenerated polyol, comprising adding a carboxylic acid and / or an anhydride thereof having two or more carboxyl groups to the aforementioned composition such that the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain. [Effects of the Invention]

[0007] This disclosure provides a technology for utilizing by-product amine compounds associated with the decomposition of polyurethane resins. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the melting point, boiling point, and structural formula of polycarboxylic acids or acid anhydrides. [Modes for carrying out the invention]

[0009] Herein lies a preferred example of this disclosure. [1] A decomposition agent is reacted with a polyurethane resin to separate it into a phase mainly composed of polyols and a phase mainly composed of amine compounds. The amine compound is reacted with a carboxylic acid compound, and the resulting reaction product is collected to obtain a composition containing the product. A method for producing a regenerated polyol, comprising adding a carboxylic acid and / or an anhydride thereof having two or more carboxyl groups to the aforementioned composition such that the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain. [2] The method for producing a regenerated polyol according to [1], wherein an alkylene oxide adduct and / or an alkanediol of an alcohol are also added to the composition. [3] A decomposing agent is reacted with the polyurethane resin to separate it into a polyol phase mainly composed of polyols and an amine phase mainly composed of amine compounds. The amine phase is recovered, A method for producing a regenerated polyol is obtained by adding a carboxylic acid and / or its anhydride having two or more carboxyl groups to the amine phase such that the ratio of the molar amount of hydroxyl groups and the total molar amount of amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain. [4] The method for producing a regenerated polyol according to [3], wherein an alkylene oxide adduct of an alcohol and / or an alkanediol is also added to the amine phase.

[0010] The disclosure is described in detail below. In this specification, when numerical ranges are described using "~", unless otherwise specified, both the lower and upper limits are included. 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". Furthermore, in this specification, the upper and lower limits of each numerical range can be combined in any way.

[0011] 1. Method for producing recycled polyols (Part 1) The first method for producing recycled polyol involves reacting a polyurethane resin with a decomposition agent to separate it into a phase mainly composed of polyol and a phase mainly composed of an amine compound (hereinafter also referred to as the first step), reacting the amine compound with a carboxylic acid compound, and recovering a composition containing the resulting reaction product (hereinafter also referred to as the second step), and adding a carboxylic acid and / or its anhydride having two or more carboxyl groups to the composition such that the ratio of the molar amount of hydroxyl groups and the total molar amount of amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl group and the acid anhydride group of the anhydride is 3 or less to obtain a recycled polyol having amide bonds and ester bonds in its molecular chain (hereinafter also referred to as the third step).

[0012] 1-1 1st process The first step involves reacting a decomposition agent with the polyurethane resin to separate it into a phase mainly composed of polyols and a phase mainly composed of amine compounds. The decomposition method for reacting the polyurethane resin with the decomposition agent to obtain decomposition products is not particularly limited as long as it allows separation into a phase mainly composed of polyols and a phase mainly composed of amine compounds. Preferred decomposition methods include amine decomposition, glycol decomposition, and hydrolysis.

[0013] (1) Polyurethane resin The polyurethane resin is not particularly limited. For example, the polyurethane resin is polyurethane foam. The polyurethane foam may be flexible polyurethane foam, semi-rigid polyurethane foam, or rigid polyurethane foam. The polyurethane foam may be open-cell polyurethane foam or closed-cell polyurethane foam. The polyurethane foam may be crushed to a predetermined size. Alternatively, the polyurethane foam may be cut pieces to a predetermined size. The polyurethane foam may be, for example, scraps discharged during the manufacturing process of polyurethane foam, or used polyurethane foam that is scheduled to be discarded.

[0014] (2) Decomposing agent From the standpoint of reactivity and cost, it is preferable that the decomposition agent be one or more selected from the group consisting of amine compounds and compounds having a hydroxyl group. The amine compound is preferably at least one selected from the group consisting of, for example, diethanolamine, diglycolamine, 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, triethanolamine, cyclohexylamine, piperazine, piperidine, aniline, toluidine, benzylamine, phenylenediamine, xylylenediamine, chloroaniline, pyridine, picoline, N-methylmorpholine, ethylmorpholine, and pyrazole. These amine compounds can be used alone or in combination of two or more. The compound having a hydroxyl group is preferably at least one selected from the group consisting of, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, and polyethylene glycol. These compounds having a hydroxyl group can be used alone or in combination of two or more.

[0015] The decomposing agent preferably contains an amine compound. That is, the decomposed product is preferably obtained by amine decomposition. When the decomposing agent contains an amine compound, the amine compound used as the decomposing agent can also be removed as a precipitate by adding a carboxylic acid-based compound. Therefore, a polyol derived from a polyurethane resin with high purity can be obtained. Further, the decomposing agent may be an amine compound having a hydroxyl group. In the case of an amine compound having a hydroxyl group, it is considered that the hydroxyl group derived from the decomposing agent contributes to the formation of an ester bond of the regenerated polyol.

[0016] The addition amount of the decomposing agent is not particularly limited. From the viewpoint of sufficiently decomposing the polyurethane resin, the addition amount of the decomposing agent is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 8 parts by mass or more, based on 100 parts by mass of the polyurethane resin. Considering the influence on the reactivity and physical properties when the decomposed product of the polyurethane resin is reused as a raw material of the polyurethane resin or the like, the addition amount of the above-mentioned decomposing agent is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 40 parts by mass or less. From these viewpoints, the addition amount of the above-mentioned decomposing agent is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, and still more preferably 8 parts by mass or more and up to 40 parts by mass.

[0017] (3) Decomposition catalyst The decomposing agent may be used in combination with a decomposition catalyst. The decomposition catalyst is not particularly limited. The decomposition catalyst is preferably one used during the production of the polyurethane resin. Examples of decomposition catalysts include diazabicycloundecene, 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, hexamethylenete It is preferable that the catalyst is one or more selected from the group consisting of lamin, 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, stanus octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutylindimaleate, dioctyltin mercaptide, dioctyltin thiocarboxylate, lead octenoate, potassium acetate, and potassium octoate. These decomposition catalysts can be used individually or in combination of two or more.

[0018] The amount of decomposition catalyst added is not particularly limited. From the viewpoint of sufficiently decomposing the polyurethane resin, the amount of decomposition catalyst added is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and may be 1 part by mass or more, per 100 parts by mass of polyurethane resin. The amount of decomposition catalyst added is preferably 30 parts by mass or less, 20 parts by mass or less, or 10 parts by mass or less, taking into consideration the effect on the reactivity and physical properties when the decomposed polyurethane resin is reused as a polyurethane resin raw material, etc. From these viewpoints, the amount of decomposition catalyst added is preferably 0.1 parts by mass or more and 30 parts by mass or less, and more preferably 0.5 parts by mass or more and 30 parts by mass or less.

[0019] (4) Decomposition conditions for polyurethane resin The conditions for decomposing polyurethane resin are not particularly limited. From the viewpoint of improving the decomposition rate, it is preferable to decompose the polyurethane resin by heating it together with a decomposing agent. When heating the polyurethane resin together with a decomposing agent, it is preferable to stir the mixture of polyurethane resin and decomposing agent.

[0020] The decomposition treatment temperature is preferably 80°C to 300°C, more preferably 100°C to 270°C, and even more preferably 150°C to 250°C, in order to improve the decomposition rate while suppressing the decomposition of polyols as polyurethane decomposition products, i.e., polyols derived from the raw material polyol. The decomposition treatment time may be, for example, 10 minutes to 24 hours, or 30 minutes to 10 hours. The end point of the decomposition treatment time may be set appropriately while checking the progress of the decomposition of the polyurethane resin, depending on the size of the polyurethane resin, whether or not it is stirred, etc. Also, for example, when decomposing the polyurethane resin at room temperature (e.g., 25°C) or below 80°C, the decomposition treatment time may be set to be longer than 24 hours.

[0021] Decomposition products include, for example, polyols derived from the raw material polyol of the polyurethane resin, and amine compounds derived from the raw material isocyanate. In addition, decomposition products may include amine compounds added as decomposition agents, flame retardants, decomposition catalysts, and other additives that were contained in the polyurethane resin.

[0022] The decomposition product is in a state where it is separated into a phase mainly composed of polyol (hereinafter also referred to as the polyol phase) and a phase mainly composed of amine compounds (hereinafter also referred to as the amine phase). When the decomposition agent contains an amine compound, the decomposition product can be preferably obtained in a state where it is separated into two phases: the polyol phase and the amine phase. It is preferable that the decomposition product be obtained as a two-phase liquid. Note that "obtained as a two-phase liquid" means that the liquid phase containing the polyol derived from the raw material polyol and the liquid phase containing the amine compound derived from the raw material isocyanate are separated. The two-phase liquid may also contain solid components that were contained in the polyurethane resin. The solid components that were contained in the polyurethane resin include, for example, fillers, components derived from polymer polyols containing polymers such as styrene and acrylonitrile, and flame retardants such as phosphorus-based flame retardants and halogen-based flame retardants.

[0023] 1-2 2nd process The second step involves reacting an amine compound with a carboxylic acid compound and recovering the composition containing the resulting reaction product.

[0024] In the second step, a carboxylic acid compound is preferably added to the entire decomposition product, which has separated into the polyol phase and the amine phase. When the amine compound in the amine phase reacts with the carboxylic acid compound, for example, the amine phase can be changed to a semi-solid phase, making it easier to recover the components derived from the amine compound from the decomposition product. In this specification, "a state in which the viscosity at 25°C is 10,000 mPa·s or more and which can be easily deformed by applying force" refers to a state in which viscosity can be easily deformed by applying force. The method for measuring viscosity will be described later. Furthermore, when a carboxylic acid compound is added to the entire decomposition product, a regenerated polyol having amide and ester bonds in its molecular chain can be obtained from the amine phase, and an even higher purity polyol can be obtained from the polyol phase. The polyol phase when the decomposition product separates into two phases is of higher purity compared to the decomposition product in a single-phase state where the polyol and amine phases are not separated. Nevertheless, some amine compounds produced as by-products during decomposition are dissolved in the polyol phase. When a carboxylic acid compound is added to the entire decomposition product, the amine compounds dissolved in the polyol phase in the second step can be reacted with the carboxylic acid compound and removed as precipitates such as amide compounds. As a result, a reduction in the amount of amine compounds dissolved in the polyol phase can also be achieved.

[0025] (1) Carboxylic acid compounds The carboxylic acid compounds of this disclosure are compounds that react with amine compounds to produce reaction products. Organic carboxylic acid compounds are preferred. Furthermore, the carboxylic acid compounds are also preferably carboxylic acids having two or more carboxyl groups and / or their anhydrides. Hereinafter, carboxylic acids having two or more carboxyl groups and / or their anhydrides will also be simply referred to as polycarboxylic acids and / or their anhydrides. The explanation of polycarboxylic acids and / or their anhydrides follows the explanation of "polycarboxylic acids and / or their anhydrides" in the third step described below. The carboxylic acid compounds can be used individually or as a mixture of two or more.

[0026] The amount of carboxylic acid compound added in the second step is not particularly limited. When the carboxylic acid compound is a polycarboxylic acid and / or its anhydride, the amount of carboxylic acid compound added may be as follows. In other words, the method for producing recycled polyols (method 1) preferably involves adding a polycarboxylic acid and / or its anhydride to a decomposition product obtained by treating a polyurethane resin with a decomposition agent, such that the ratio of the molar amount of carboxyl groups and carboxyl groups derived from the acid anhydride group of the anhydride to the molar amount of amino groups in the decomposition product is 0.5 or more and 1.2 or less. The ratio of the molar amount of carboxyl groups to the molar amount of amino groups in the decomposition product is more preferably 0.6 or more and 1.1 or less, and even more preferably 0.65 or more and 1.0 or less. If the above molar ratio is greater than or equal to the above lower limit, the amine compounds in the decomposition products can be suitably precipitated as precipitates. Furthermore, if the above molar ratio is less than or equal to the above upper limit, the amount of carboxylic acid compounds mixed into the polyol phase when the polyol phase is recovered can be suitably reduced.

[0027] The molar amount of amino groups in the decomposition product can be calculated by measuring the total amine value in accordance with JIS K 1557-7. If the decomposition product is separated into a polyol phase and an amine phase, the molar amount of amino groups in the decomposition product can be calculated by measuring the total amine value of each phase in accordance with JIS K 1557-7 and using a weighted average from the mass ratio of the polyol phase and the amine phase.

[0028] The total amine value of the polyol phase is not particularly limited. For example, the total amine value of the polyol phase may be between 30 mg KOH / g and 300 mg KOH / g, between 40 mg KOH / g and 200 mg KOH / g, or between 60 mg KOH / g and 180 mg KOH / g. The total amine value of the amine phase is not particularly limited. For example, the total amine value of the amine phase may be between 80 mg KOH / g and 500 mg KOH / g, between 100 mg KOH / g and 400 mg KOH / g, or between 150 mg KOH / g and 350 mg KOH / g. The mass ratio of the polyol phase to the amine phase (polyol phase:amine phase) is not particularly limited. For example, the polyol phase:amine phase ratio may be 10:90 to 90:10, 25:75 to 80:20, or 40:60 to 75:25.

[0029] The molar amount of carboxyl groups can be calculated as the sum of the value obtained by multiplying the molar amount of the added polycarboxylic acid by the number of carboxyl groups, and the value obtained by multiplying the molar amount of the added acid anhydride by twice the number of acid anhydride groups.

[0030] (2) Conditions for adding carboxylic acid compounds In the second step, it is preferable to add a carboxylic acid compound to the decomposition product and heat it. The heating temperature is not particularly limited. From the viewpoint of precipitate formation, the heating temperature should be 150°C or higher, but may be 160°C or higher, 170°C or higher, or 180°C or higher. The upper limit of the heating temperature is not particularly limited. From the viewpoint of suppressing vaporization and decomposition of the carboxylic acid compound, the upper limit of the heating temperature should be, for example, 280°C or lower, but may be 260°C or lower, 240°C or lower, or 220°C or lower.

[0031] The above heating may be carried out using the residual heat generated during the decomposition process of the polyurethane resin. For example, by adding a carboxylic acid compound before the heated decomposition product cools to room temperature and then performing the above heating, the heating and cooling time during the addition of the carboxylic acid compound can be shortened, and energy such as electricity can be reduced.

[0032] The heating time may be, for example, 10 minutes to 24 hours, or 30 minutes to 10 hours. The end point of the heating time may be set as appropriate, while confirming that the total amine value and / or hydroxyl value of the decomposition product have been sufficiently reduced.

[0033] In the second step, the mixture of the decomposition product and the carboxylic acid compound may be stirred during the heating process described above. Since dehydration condensation occurs when a carboxylic acid compound is added and heated, the method for producing regenerated polyols may involve supplying a dry gas during the heating process. For example, the decomposition product and the carboxylic acid compound may be placed in a container and heated, and a dry gas may be supplied into the container from an external gas source. Dry nitrogen is a suitable dry gas, for example. Furthermore, the removal of moisture may be accelerated by reducing the pressure. There are no particular restrictions on the degree of vacuum during this reduction, but for example, 104 Pa or less is preferable, 10 3 Pa or less is more preferable, 10 2 Pa or lower is even more preferable.

[0034] (3) Composition containing reaction products When a carboxylic acid compound is added to the decomposition product, a composition is obtained that contains a reaction product between the amine compound derived from the decomposition product and the carboxylic acid compound. The reaction product is not particularly limited. The type of reaction product can be appropriately controlled depending on the type of amine compound and carboxylic acid compound, the heating temperature, etc. It is presumed that the reaction product is one or more selected from the group consisting of, for example, salts of the amine compound and the carboxylic acid compound, and amide compounds (including imide compounds) having a structure derived from the amine compound and / or the carboxylic acid compound. The composition contains at least a reaction product between the amine compound derived from the decomposition product and the carboxylic acid compound, and may also contain one or more selected from the group consisting of an amine compound that has not reacted with the carboxylic acid compound, a polyol, a decomposition agent, a carboxylic acid compound, and their reaction products.

[0035] The composition is preferably in a semi-solid phase. As described above, the treated product obtained by adding a carboxylic acid compound to the decomposition product (hereinafter also referred to as the acid-added product) may be obtained in a state of separation into two phases: a polyol phase and a semi-solid phase. In this case, the composition containing the reaction product can be suitably recovered as a semi-solid phase. In this disclosure, the semi-solid phase may exist separately from the polyol phase, for example, as a phase containing a large amount of precipitate. The composition is not limited to being obtained as a semi-solid phase, and may also be obtained as a liquid phase with higher viscosity than the polyol phase, or as a phase containing some or all of the polyol component.

[0036] If the composition is a semi-solid phase, the semi-solid phase may be recovered from the acid-treated material and used as part of the composition in the third step. The method for recovering the semi-solid phase from the acid-treated material is not particularly limited. For example, the semi-solid phase can be recovered by filtering the acid-treated material. Alternatively, the solid phase may be recovered by removing only the polyol phase from the container containing the acid-treated material, or the semi-solid phase may be recovered by separating the acid-treated material by centrifugation. The polyol phase separated after recovering the semi-solid phase can be used directly as a recycled polyol raw material.

[0037] The total amine value of the semi-solid phase is not particularly limited. Preferably, the total amine value of the semi-solid phase is 130 mgKOH / g or less, more preferably 120 mgKOH / g or less, and even more preferably 110 mgKOH / g or less. The lower limit of the total amine value of the semi-solid phase is not particularly limited. For example, the total amine value of the semi-solid phase is 50 mgKOH / g or more. The total amine value of the semi-solid phase can be measured in accordance with JIS K 1557-7.

[0038] The hydroxyl value of the semi-solid phase is not particularly limited. For example, the hydroxyl value of the semi-solid phase may be 100 mg KOH / g or more and 500 mg KOH / g or less, 150 mg KOH / g or more and 400 mg KOH / g or less, or 200 mg KOH / g or more and 350 mg KOH / g or less. The hydroxyl value of the semi-solid phase can be measured in accordance with JIS K 1557-1. The hydroxyl groups in the semi-solid phase may include, for example, hydroxyl groups derived from the decomposition agent, as well as hydroxyl groups derived from the polyurethane resin.

[0039] By performing the second step described above, the amine compounds in the decomposition product can be suitably recovered as a composition and used in the third step. Furthermore, when polyurethane resins derived from aromatic isocyanates are decomposed, harmful aromatic amine compounds may be contained in the decomposition product. By using the decomposition product as a composition obtained through the second step in the third step, the various operations described later can be performed with a reduced amount of aromatic amine compounds, thereby improving safety during the work.

[0040] 1-3 3rd process The third step involves adding a carboxylic acid and / or its anhydride having two or more carboxyl groups to the composition such that the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide and ester bonds in its molecular chain. Hereinafter, the carboxylic acid and / or its anhydride having two or more carboxyl groups will also be simply referred to as a polycarboxylic acid and / or its anhydride.

[0041] If a polycarboxylic acid and / or its anhydride is used in the second step described above, the same type of polycarboxylic acid and / or its anhydride may be used in the third step, or a different type of polycarboxylic acid and / or its anhydride may be used.

[0042] (1) Polycarboxylic acids and / or their anhydrides Polycarboxylic acids and / or their anhydrides are not particularly limited. Polycarboxylic acids and / or their anhydrides can be used individually or in combination of two or more. The number of carboxyl groups in polycarboxylic acids and / or their anhydrides is preferably 2 to 4, and more preferably 2 or 3. Polycarboxylic acids and / or their anhydrides may be aromatic carboxylic acids or aliphatic carboxylic acids. The number of carbon atoms in polycarboxylic acids and / or their anhydrides is preferably 2 to 20, more preferably 2 to 12, and even more preferably 3 to 10. The number of carbon atoms as used herein includes the number of carbon atoms in the carboxyl group. The boiling point or decomposition temperature of polycarboxylic acids and / or their anhydrides at atmospheric pressure is preferably 135°C or higher, more preferably 140°C or higher, and even more preferably 150°C or higher. The upper limit of the above boiling point or decomposition temperature is not particularly limited, and is usually 500°C or lower. The melting point of polycarboxylic acids and / or their anhydrides at atmospheric pressure is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 220°C or lower. The lower limit of the above melting point is not particularly limited, and is usually 20°C or higher, but may be 50°C or higher, 80°C or higher, or 95°C or higher.

[0043] The polycarboxylic acid and / or its anhydride is preferably one or more selected from the group consisting of, for example, oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanediic acid, dipropylmalonic acid, maleic acid, trans-3-hexenodioic acid, itaconic acid, phthalic acid, malic acid, L(+)-tartaric acid, citric acid, trans-aconitic acid, 2,3-pyridinedicarboxylic acid, succinic anhydride, maleic anhydride, phthalic anhydride, and trimellitic anhydride. The melting point, boiling point, and structural formula of the above compounds are shown in Figure 1. For compounds where the boiling point column is blank or "-", the boiling point or decomposition temperature is 150°C or higher.

[0044] (2) The ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups of polycarboxylic acids and the acid anhydride groups of anhydrides. The above molar ratio is 3 or less, preferably 2.6 or less, more preferably 2.3 or less, and may also be 2 or less, 1.8 or less, or 1.6 or less. The lower limit of the above molar ratio is not particularly limited and may be, for example, 0.5 or more, 0.8 or more, or 1 or more. Within the above range, the hydroxyl value of the recycled polyol, i.e., the number-average molecular weight of the recycled polyol, can be designed to be within a desirable range. Therefore, for example, when the recycled polyol is reused as a raw material for polyurethane resin, it is easier to ensure the physical properties of the polyurethane resin, making it suitable. Furthermore, within the above range, the total amine value of the recycled polyol is not too high, making it easy to reuse for various applications.

[0045] The molar amount of carboxyl groups can be calculated as the sum of the value obtained by multiplying the molar amount of the added polycarboxylic acid by the number of carboxyl groups, and the value obtained by multiplying the molar amount of the added acid anhydride by twice the number of acid anhydride groups.

[0046] The total molar amount of hydroxyl groups and amino groups in a composition can be calculated by measuring the hydroxyl value and total amine value of the composition in accordance with JIS K 1557-1 and JIS K 1557-7. The hydroxyl value and total amine value of the composition are not particularly limited. If the above-mentioned semi-solid phase is used as the composition, the hydroxyl value and total amine value of the semi-solid phase shall be applied as the hydroxyl value and total amine value of the composition. If an alcohol alkylene oxide adduct and / or alkanediol described below is added to the composition, the hydroxyl groups of these additives shall also be included in the hydroxyl groups of the composition.

[0047] (2) Alkylene oxide adducts and / or alkanediols of alcohols The first method for producing recycled polyols may also include the addition of an alcohol alkylene oxide adduct and / or alkanediol to the composition, from the viewpoint of obtaining a liquid recycled polyol. The alcohol alkylene oxide adduct and / or alkanediol are thought to contribute to the formation of ester bonds in the recycled polyol. The alcohol alkylene oxide adduct and / or alkanediol can be used alone or in a mixture of two or more. Hereinafter, the alcohol alkylene oxide adduct and / or alkanediol will also be simply referred to as alcohols.

[0048] Alkylene oxide adducts of alcohols are preferably bifunctional. Bifunctional alcohol alkylene oxide adducts can be obtained, for example, by reacting a bifunctional alcohol as an initiator with an alkylene oxide such as ethylene oxide or propylene oxide. Specific examples of alcohol alkylene oxide adducts include diethylene glycol, polyethylene glycol with a hydroxyl value of 500 mgKOH / g or more, dipropylene glycol, and polypropylene glycol with a hydroxyl value of 500 mgKOH / g or more. The alkanediol is more preferably selected from the group consisting of, for example, alkane diols having 2 to 10 carbon atoms and mixtures thereof. Specific examples of alkane diols having 2 to 10 carbon atoms include 1,4-butanediol, 3-methyl,1,5-pentanediol, ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl,1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-butyl,2-ethyl,1,3-propanediol, and the like.

[0049] The amount of alcohols added is not particularly limited. From the viewpoint of obtaining a liquid recycled polyol, the amount of alcohols added is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, per 100 parts by mass of the composition. The amount of alcohols added is preferably 250 parts by mass or less, more preferably 200 parts by mass or less, and even more preferably 175 parts by mass or less, taking into consideration the effect on the reactivity and physical properties when the recycled polyol is reused as a polyurethane resin raw material, etc. From these viewpoints, the amount of alcohols added is preferably 15 parts by mass or more and 250 parts by mass or less, more preferably 20 parts by mass or more and 200 parts by mass or less, and even more preferably 25 parts by mass or more and 175 parts by mass or less.

[0050] (3) Synthesis conditions for recycled polyols The third step preferably involves adding a polycarboxylic acid and / or its anhydride to the composition and heating it. The heating temperature is not particularly limited. From the viewpoint of promoting the synthesis of regenerated polyols, the heating temperature should be 150°C or higher, but may be 160°C or higher, 170°C or higher, or 180°C or higher. The upper limit of the heating temperature is not particularly limited. From the viewpoint of suppressing vaporization and decomposition of the polycarboxylic acid and / or its anhydride, the upper limit of the heating temperature should be, for example, 280°C or lower, but may be 260°C or lower, 240°C or lower, or 220°C or lower.

[0051] The heating time may be, for example, 10 minutes to 24 hours, or 30 minutes to 10 hours. The end point of the heating time may be set as appropriate, while confirming that the total amine value and / or hydroxyl value of the acid-treated product have been sufficiently reduced.

[0052] When polycarboxylic acids and / or their anhydrides are added and heated, dehydration condensation occurs. Therefore, in the method for producing the solid, a dry gas may be supplied during the heating process. For example, the decomposition product and the polycarboxylic acid and / or its anhydride may be placed in a container and heated, and a dry gas may be supplied into the container from an external gas source. Dry nitrogen is a suitable dry gas, for example.

[0053] The method for producing recycled polyols may include the addition of an esterification catalyst along with a polycarboxylic acid and / or its anhydride, from the viewpoint of promoting the synthesis of recycled polyols. The esterification catalyst is not particularly limited. Examples of esterification catalysts include metal compounds such as titanium, aluminum, zinc, manganese, antimony, tin, zirconium, and germanium; alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; phosphite compounds; phosphoric acid compounds; amine compounds, etc. Specific examples of titanium compounds include tetrabutyl orthotitanate, tetraisobutyl orthotitanate, tetraisopropyl orthotitanate, tetra(tetradecyl) orthotitanate, tetraoctadecyl orthotitanate, dioctyldihydroxyoctyl orthotitanate, and dioctyldi(tetradecyl) orthotitanate.

[0054] The amount of esterification catalyst added is preferably 0.001 parts by mass or more and 1 part by mass or less, more preferably 0.005 parts by mass or more and 0.5 parts by mass or less, and even more preferably 0.01 parts by mass or more and 0.2 parts by mass or less, per 100 parts by mass of polyester polyurethane resin.

[0055] (4) Recycled polyols Regenerated polyols are polyols having amide and ester bonds in their molecular chains. It is presumed that regenerated polyols are synthesized by the following reaction mechanism. However, the technology described herein is not limited to this presumed reaction mechanism. The composition contains compounds having amino groups as well as compounds having hydroxyl groups. When the amino groups in the composition undergo dehydration condensation with the carboxyl groups of the polycarboxylic acid and / or its anhydride, an amide bond is formed. When the hydroxyl groups in the composition undergo dehydration condensation with the carboxyl groups of the polycarboxylic acid and / or its anhydride, an ester bond is formed. The method for producing the regenerated polyol of this disclosure is presumed to synthesize a regenerated polyol (hereinafter also referred to as a polyamide-polyester polyol) having amide bonds and ester bonds in its molecular chain by dehydration condensation of polycarboxylic acids and / or their anhydrides having multiple carboxyl groups in the molecule.

[0056] The treated product obtained by adding a polycarboxylic acid and / or its anhydride to the composition is preferably a single-phase state in which the liquid phase containing the regenerated polyol is not clearly separated. That is, it is preferable that the phase containing the regenerated polyol is homogeneous. The phase containing the regenerated polyol can be obtained as a liquid phase from a semi-solid phase, for example. If the phase containing the regenerated polyol is homogeneous, the acid-added treated product can be used directly as regenerated polyol. That is, if the phase containing the regenerated polyol is homogeneous, a regenerated polyurethane raw material can be obtained simply and without generating waste, without requiring any special removal work after the reaction with the polycarboxylic acid and / or its anhydride. If solids or a phase that separates from the phase containing the regenerated polyol are present in the treated product obtained by adding the polycarboxylic acid and / or its anhydride, the solids or the separated phase may be removed to obtain the regenerated polyol.

[0057] The hydroxyl value of the regenerated polyol is preferably 250 mg KOH / g or less, more preferably 200 mg KOH / g or less, and even more preferably 150 mg KOH / g or less. The lower limit of the hydroxyl value of the regenerated polyol is not particularly limited. For example, the hydroxyl value of the regenerated polyol is 20 mg KOH / g or more. The hydroxyl value of the regenerated polyol can be controlled, for example, by adjusting the number and amount of functional groups of the polycarboxylic acid and / or its anhydride. The hydroxyl value of recycled polyols can be measured in accordance with JIS K1557-1.

[0058] The total amine value of the regenerated polyol is preferably 35 mgKOH / g or less, more preferably 30 mgKOH / g or less, and may also be 25 mgKOH / g or less, 20 mgKOH / g or less, 15 mgKOH / g or less, or 10 mgKOH / g or less. The lower limit of the total amine value of the regenerated polyol is not particularly limited. The total amine value of the regenerated polyol may be 0 mgKOH / g or more. The total amine value of recycled polyols can be measured in accordance with JIS K1557-7.

[0059] The number-average molecular weight of the recycled polyol is not particularly limited. For example, the number-average molecular weight of the recycled polyol may be between 800 and 10000, or between 1000 and 5000, or between 1500 and 3000. The number-average molecular weight of the recycled polyol can be measured as a polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0060] The average number of functional groups in a regenerated polyol is not particularly limited. For example, the average number of functional groups in a regenerated polyol may be between 2 and 6, between 2.5 and 4.5, or between 2.5 and 3.5. The average number of functional groups in a regenerated polyol can be controlled by adjusting, for example, the number of functional groups in polycarboxylic acids and / or their anhydrides, or the number of functional groups in alcohols.

[0061] If the hydroxyl value and total amine value of the recycled polyol are within the above range, the recycled polyol can be suitably used as a recycled raw material. The applications of recycled polyols are not particularly limited. For example, recycled polyols can be used as a recycled raw material to obtain recycled resins. Specifically, recycled polyols can be used in foam applications such as rigid polyurethane foam and flexible polyurethane foam, as well as in non-foaming polyurethane applications such as adhesives, sealants, and elastomers. The recycled resin may be a thermoplastic resin or a thermosetting resin. One method for producing recycled polyurethane resin is to mix recycled polyol with isocyanate to obtain the polyurethane resin. Recycled polyurethane resin can be produced by known methods. When obtaining polyurethane foam, there are two foaming methods: slab foaming and mold foaming, and either molding method is acceptable. Slab foaming is a method in which the mixed recycled polyol and isocyanate are discharged onto a belt conveyor and foamed at atmospheric pressure and room temperature. On the other hand, mold foaming is a method in which the mixed recycled polyol and isocyanate are filled into a mold and foamed inside the mold.

[0062] 2. Method for producing recycled polyols (Part 2) The second method for producing recycled polyol involves reacting a polyurethane resin with a decomposition agent to separate it into a phase mainly composed of polyol and a phase mainly composed of an amine compound (hereinafter also referred to as the first step), recovering the amine phase (hereinafter also referred to as the second A step), and adding a carboxylic acid having two or more carboxyl groups and / or its anhydride to the amine phase such that the ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a recycled polyol having amide bonds and ester bonds in its molecular chain (hereinafter also referred to as the third A step).

[0063] In the method for producing recycled polyols (part 2), the explanation of the first step is the same as the explanation of "1-1 First Step" in the method for producing recycled polyols (part 1).

[0064] 2-1 2nd A process Step 2A involves recovering the amine phase. Specifically, Step 2A recovers the amine phase from the decomposition product, which is a state in which the polyol phase and the amine phase have been separated. The method for recovering the amine phase from the decomposition product is not particularly limited. For example, the amine phase can be recovered as the remainder after removing only the polyol phase from the container containing the decomposition product. It is preferable that the amine phase is more viscous than the polyol phase, as this makes it easier to remove only the polyol phase from the decomposition product. The recovered regenerated polyol can be used as is as a regenerating raw material.

[0065] Step 2A in the method for producing recycled polyols (part 2) differs from step 2 in the method for producing recycled polyols (part 1) in that it involves recovering the amine phase. Step 2A eliminates the step of reacting the amine compound with a carboxylic acid compound in step 2, thus reducing the number of steps compared to step 2.

[0066] (1) Amine phase The amine phase may contain at least an amine compound derived from a polyurethane resin, and may also contain one or more selected from the group consisting of polyols, decomposition agents, and reaction products thereof.

[0067] The total amine value of the amine phase is not particularly limited. Preferably, the total amine value of the amine phase is 350 mgKOH / g or less, more preferably 300 mgKOH / g or less, and even more preferably 300 mgKOH / g or less. The lower limit of the total amine value of the amine phase is not particularly limited. For example, the total amine value of the amine phase is 50 mgKOH / g or more. The total amine value of the amine phase can be measured in accordance with JIS K 1557-7.

[0068] The hydroxyl value of the amine phase is not particularly limited. For example, the hydroxyl value of the amine phase may be between 200 mg KOH / g and 650 mg KOH / g, between 250 mg KOH / g and 600 mg KOH / g, or between 300 mg KOH / g and 550 mg KOH / g. The hydroxyl value of the amine phase can be measured in accordance with JIS K 1557-1. The hydroxyl groups in the amine phase may include, for example, hydroxyl groups derived from the decomposition agent, as well as hydroxyl groups derived from the polyurethane resin.

[0069] 2-2 3rd A process Step 3A involves adding a carboxylic acid having two or more carboxyl groups and / or its anhydride to the amine phase such that the ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain.

[0070] For the explanation of carboxylic acids and / or their anhydrides having two or more carboxyl groups in step 3A, the explanation in "(1) Polycarboxylic acids and / or their anhydrides" in "1-3 Step 3" shall be applied as is.

[0071] (1) The ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups of polycarboxylic acids and the acid anhydride groups of anhydrides. The above molar ratio is 3 or less, preferably 2.6 or less, more preferably 2.3 or less, and may also be 2 or less, 1.8 or less, or 1.6 or less. The lower limit of the above molar ratio is not particularly limited and may be, for example, 0.5 or more, 0.8 or more, or 1 or more. Within the above range, the hydroxyl value of the recycled polyol, i.e., the number-average molecular weight of the recycled polyol, can be designed to be within a desirable range. Therefore, for example, when the recycled polyol is reused as a raw material for polyurethane resin, it is easier to ensure the physical properties of the polyurethane resin, making it suitable. Furthermore, within the above range, the total amine value of the recycled polyol is not too high, making it easy to reuse for various applications.

[0072] The molar amount of carboxyl groups can be calculated as the sum of the value obtained by multiplying the molar amount of the added polycarboxylic acid by the number of carboxyl groups, and the value obtained by multiplying the molar amount of the added acid anhydride by twice the number of acid anhydride groups.

[0073] The total molar amount of hydroxyl groups and amino groups in the amine phase can be calculated by measuring the hydroxyl value and total amine value of the composition in accordance with JIS K 1557-1 and JIS K 1557-7. The hydroxyl value and amine value of the amine phase are not particularly limited. When alkylene oxide adducts and / or alkanediols of alcohols, as described below, are added to the amine phase, the hydroxyl groups of these additives are also included in the hydroxyl groups of the amine phase.

[0074] In the method for producing recycled polyols (part 2), from the viewpoint of obtaining a liquid recycled polyol, an alkylene oxide adduct of an alcohol and / or an alkanediol may also be added to the amine phase. The explanation of the alkylene oxide adduct of an alcohol and / or an alkanediol in step 3A is the same as the explanation of "(2) Alkylene oxide adduct of an alcohol and / or an alkanediol" in "1-3 Step 3".

[0075] For the synthesis conditions of the recycled polyol in step 3A, and for the description of the recycled polyol, the explanations in "(3) Synthesis conditions of recycled polyol" and "(4) Recycled polyol" in "1-3 Step 3" shall be applied as is.

[0076] 3. Effects of this embodiment The method for producing recycled polyols in this embodiment allows for the effective utilization of amine by-products obtained along with polyols during the decomposition of polyurethane resins as recycled raw materials. Amine by-products themselves have a small molecular weight and a high amino group content, making them too reactive and difficult to use as raw materials for polyurethane resins, etc. On the other hand, this embodiment synthesizes recycled polyols having amide and ester bonds in their molecular chains from amine by-products, etc., which can then be utilized in various applications. Furthermore, in the method for producing recycled polyols according to this embodiment, if heating, reduced pressure, etc. are applied during the dehydration condensation process, volatile impurities (e.g., siloxane compounds, etc.) can be effectively removed. Therefore, a relatively high-purity raw material can be obtained without performing any special purification work separate from the dehydration condensation process. Furthermore, the method for producing recycled polyols in this embodiment allows for obtaining recycled polyols suitable for reuse by appropriately setting the type of decomposition agent, the type and amount of polycarboxylic acid and / or its anhydride in the third step. [Examples]

[0077] 1. Manufacturing of biodegradable polyurethane resin Polyurethane foam compositions (liquid A and liquid B) were prepared in the proportions shown in Table 1, and polyurethane foam was produced as a decomposable polyurethane resin by slab foaming. The density of the obtained polyurethane foam was measured in accordance with JIS K7222:2005. The measured densities are also shown in Table 1.

[0078] Details of each ingredient are as follows: • Polyol: Polyether polyol, number average molecular weight 3000, number of functional groups 3, hydroxyl value 56.1 mgKOH / g, product name: Sannix GP-3050NS, manufactured by Sanyo Chemical Industries, Ltd. • Amine catalyst: Product name: DABCO 33LSI, manufactured by EVONIK. • Foam stabilizer: Silicone foam stabilizer, product name: L-595, manufactured by Momentive. • Tin catalyst: Stannous octylate, Product name: MRH-110, Manufactured by Johoku Chemical Industry Co., Ltd. • Foaming agent: Water • Isocyanate: Tolylene diisocyanate, product name Cosmonate T-80, manufactured by Mitsui Chemicals, NCO%: 48.2%

[0079] [Table 1]

[0080] 2. Decomposition treatment of polyurethane resin (first step) In a 1 L separable flask, 100 g of the polyurethane resin to be decomposed was mixed with 15 g of decomposition agent [1] and 0.5 g of decomposition catalyst. The mixture was heated at 200 °C for 6 hours with stirring to obtain decomposition product [1]. Decomposition product [2] was obtained in the same manner, except that 15 g of decomposition agent [2] was used instead of 15 g of decomposition agent [1]. Details of decomposition agent [1], decomposition agent [2], and decomposition catalyst are as follows. The decomposition product was separated into two phases: a polyol phase (upper phase) and an amine phase (lower phase). • Decomposing agents [1]: Amine compounds, diglycolamine • Decomposing agents [2]: Amine compounds, diethanolamine • Decomposition catalyst: Diazabicycloundecene (DBU)

[0081] The total amine value and hydroxyl value of the polyol phase and amine phase of the obtained decomposition product [1] were measured in accordance with JIS K 1557-7 and JIS K 1557-1. The mass percentage (mass%) of the polyol phase and the amine phase were also calculated, assuming the entire decomposition product [1] was 100% by mass. The total amine value and hydroxyl value of the entire decomposition product [1] were calculated based on the following equations 1 and 2. Similarly, for the decomposition product [2], the total amine value and hydroxyl value of the polyol phase and amine phase were measured, and the mass percentage (mass%) of the polyol phase and amine phase, as well as the total amine value and hydroxyl value of the entire decomposition product [2], were calculated. These results are shown in Table 2. Total amine value of decomposition products = Total amine value of the polyol phase × Mass ratio of the polyol phase + Total amine value of the amine phase × Mass ratio of the amine phase ... (Equation 1) Hydroxyl value of decomposition products = Hydroxyl value of the polyol phase × Mass ratio of the polyol phase + Hydroxyl value of the amine phase × Mass ratio of the amine phase ... (Equation 2)

[0082] [Table 2]

[0083] 3. Addition of carboxylic acid compounds (second step) The obtained decomposition product [1] was combined with the carboxylic acid compounds listed in Table 3 to obtain samples of compositions [1] to [5]. The obtained decomposition product [2] was combined with the carboxylic acid compounds listed in Table 3 to obtain a sample of composition [6]. First, polycarboxylic acids listed in Table 2 were added to the decomposition product [1] or decomposition product [2] in a 1 L separable flask. The amount of polycarboxylic acid added was adjusted so that the ratio of the molar amount of carboxyl groups to the molar amount of amino groups in the decomposition product was as shown in the "mol ratio" column of Table 3. Ratio of the molar amount of carboxyl groups to the molar amount of amino groups in the decomposition product = Molar amount of carboxyl groups in carboxylic acid compounds / Molar amount of amino groups in decomposition products

[0084] The molar amount of amino groups in the decomposition product was calculated from the total amine value of the above decomposition product [1] or decomposition product [2]. The molar amount of carboxyl groups was calculated by multiplying the molar amount of the added carboxylic acid compound by the number of carboxyl groups, or by multiplying the molar amount of the added acid anhydride by twice the number of acid anhydride groups. For example, the molar amount of carboxyl groups in 1 mole of adipic acid was assumed to be 2 moles.

[0085] The above carboxylic acid compounds were added to the decomposition product [1] or decomposition product [2] and heated at a reaction temperature of 150°C or higher and below the boiling point of the carboxylic acid compound (or the decomposition temperature if the carboxylic acid compound does not have a boiling point). The heating time was 3 hours. After the addition of the carboxylic acid compound, dehydration condensation occurred, so the reaction was carried out while flowing dry nitrogen. After the reaction, each sample separated into two phases: a liquid phase and a semi-solid phase.

[0086] Each reaction sample was filtered through a 300-mesh stainless steel mesh to separate and recover each phase, and the semi-solid phase was recovered as compositions [1] to [6]. For each of compositions [1] to [6], the total amine value and hydroxyl value were measured in accordance with JIS K 1557-7 and JIS K 1557-1. In addition, the viscosity of the recovered compositions [1] and others was measured using E-type viscosity. E-type viscosity was measured at a measurement temperature of 25°C using a "TV25 type viscometer Type H" (measurement limit: 500,000 mPa·s) manufactured by Toki Sangyo Co., Ltd. The results are shown in Table 3.

[0087] Compositions [1] to [6] are used in Examples 3 to 15 (Step 3) and Comparative Example 2 in "5. Synthesis of Regenerated Polyols" described below.

[0088] 4. Recovery of the amine phase (Step 2A) The amine phase of the decomposition product [1] was recovered to obtain a sample of amine phase [1]. Similarly, the amine phase of the decomposition product [2] was recovered to obtain a sample of amine phase [2]. The total amine value and hydroxyl value of amine phase [1] and amine phase [2] are shown in Table 2.

[0089] The amine phase [1] and the amine phase [2] are used in Example 1, Example 2 (Step 3A), and Comparative Example 1 in "5. Synthesis of Regenerated Polyols" described later.

[0090] [Table 3]

[0091] 5. Synthesis of recycled polyols (1) Example 1, Example 2 (Step 3A) In Example 1, 60 parts by mass of adipic acid and 0.1% of tetrabutyl orthotitanate (CAS: 5593-70-4) as an esterification catalyst (0.1 parts by mass per 100 parts by mass of amine phase [1]) were added to 100 parts by mass of amine phase [1]. The mixture was then heated under reduced pressure at 210°C for 8 hours to obtain a regenerated polyol. In Example 2, 80 parts by mass of adipic acid were added to 100 parts by mass of the amine phase [2]. The regenerated polyol was obtained in the same manner as in Example 1.

[0092] (2) Examples 3 to 7, Examples 11 to 15 (Third step) Examples 3 to 7 and Examples 11 to 15 were prepared by adding the polycarboxylic acids and / or their anhydrides listed in Tables 4 and 5 to 100 parts by mass of Composition [1] to Composition [6] in the mass proportions listed in Tables 4 and 5. Otherwise, the regenerated polyols were obtained in the same manner as in Example 1.

[0093] (3) Examples 8 to 10 (Third step) In Examples 8 to 10, 100 parts by mass of composition [1] were mixed with polycarboxylic acids and / or their anhydrides listed in Table 4 in the mass proportions listed in Table 4, and then alcohols listed in Table 4 were added in the mass proportions listed in Table 4. The regenerated polyols were obtained in the same manner as in Example 1.

[0094] (4) Comparative Example 1, Comparative Example 2 Comparative Example 1 involved adding 20 parts by mass of adipic acid to 100 parts by mass of the amine phase [1]. The regenerated polyol was obtained in the same manner as in Example 1. Comparative Example 2 involved adding 12 parts by mass of adipic acid to 100 parts by mass of composition [1]. The regenerated polyol was obtained in the same manner as in Example 1.

[0095] (5) [Hydroxy group + Amino group] / [Carboxy group] in the amine phase In Example 1, Example 2, and Comparative Example 1, the ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups of the polycarboxylic acid and / or the acid anhydride groups of the anhydride was calculated. The results are shown in Table 4. The molar amount of hydroxyl groups in the amine phase was calculated from the hydroxyl value of the amine phase [1] or amine phase [2] described above. The molar amount of amino groups in the amine phase was calculated from the total amine value of the amine phase [1] or amine phase [2] described above. The molar amount of carboxyl groups was calculated by multiplying the molar amount of the added polycarboxylic acid by the number of carboxyl groups, or by multiplying the molar amount of the added acid anhydride by twice the number of acid anhydride groups. For example, the molar amount of carboxyl groups in 1 mole of adipic acid was assumed to be 2 moles.

[0096] (6) [Hydroxygroup + Aminogroup] / [Carboxygroup] in the composition In Examples 3 to 7, Examples 11 to 15, and Comparative Example 2, the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups of the polycarboxylic acid and / or the acid anhydride groups of the anhydride was calculated. The results are shown in Tables 4 and 5. The molar amount of hydroxyl groups in the composition was calculated from the hydroxyl value of compositions [1] to [6] described above. The molar amount of amino groups in the composition was calculated from the total amine values ​​of the above compositions [1] to [6]. The molar amount of carboxyl groups was calculated in the same way as in "(5) [Hydroxyl group + Amino group] / [Carboxyl group] in the amine phase" above.

[0097] The molar ratios [hydroxyl group + amino group] / [carboxyl group] were calculated for Examples 8 to 10. The results are shown in Table 4. The molar amount of hydroxyl groups in the composition was calculated from the number of hydroxyl groups derived from the hydroxyl value of compositions [1] to [6] above, the number of hydroxyl groups in one molecule of alcohols, and their respective proportions. The molar amount of amino groups in the compositions was calculated from the total amine values ​​of compositions [1] to [6] described above. Note that the alcohols used in Examples 8 to 10 do not contain amino groups, so the amino groups in the alcohols were not considered. The molar amount of carboxyl groups was calculated in the same way as in "(5) [Hydroxyl group + Amino group] / [Carboxyl group] in the amine phase" above.

[0098] [Table 4]

[0099] [Table 5]

[0100] 6. Evaluation The resulting recycled polyol was visually inspected to assess its condition. Furthermore, the hydroxyl value and total amine value of the obtained recycled polyols were measured in accordance with JIS K 1557-1 and JIS K 1557-7. The results are shown in Tables 4 and 5.

[0101] The number-average molecular weight of the regenerated polyol in Example 1, as measured by gel permeation chromatography (GPC), was 1656. The recycled polyol from Example 1 was analyzed by Fourier transform infrared spectroscopy (FT-IR). Fourier transform infrared spectroscopy was used to determine the wavenumber 3300 cm⁻¹. -1 ~3100cm -1 A peak originating from the NH group of the amide bond was observed. Also, wave number 1000cm-1 ~1300 cm -1 a peak derived from an ester bond could be confirmed. Wavenumber 1650 cm -1 ~1770 cm -1 a peak derived from an amide bond could also be confirmed.

[0102] [[ID=1十二]] 7. Results (1) Example 1, Example 2 (Method for Producing Recycled Polyol (Part 2)) The methods for producing recycled polyol in Example 1 and Example 2 satisfy the following requirements (a) to (c). The method for producing recycled polyol in Comparative Example 1 does not satisfy the following requirement (c). · Requirement (a): React a decomposing agent with a polyurethane resin to separate it into a polyol phase mainly composed of polyol and an amine phase mainly composed of an amine compound. · Requirement (b): Recover the amine phase. · Requirement (c): Add a carboxylic acid having two or more carboxy groups and / or its anhydride to the amine phase so that the ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxy groups derived from the carboxy groups and acid anhydride groups of the anhydride is 3 or less, to obtain a recycled polyol having an amide bond and an ester bond in the molecular chain.

[0103] In Comparative Example 1, the hydroxyl value of the recycled polyol was large, and it is presumed that the synthesis of the recycled polyol did not proceed sufficiently. In Comparative Example 1, the total amine value of the recycled polyol was large, and there is a possibility that the reactivity of the recycled polyol is too high. On the other hand, in Example 1 and Example 2, the hydroxyl value of the recycled polyol was smaller than that in Comparative Example 1, and it is presumed that the synthesis of the recycled polyol proceeded. In Example 1 and Example 2, the total amine value of the recycled polyol was smaller than that in Comparative Example 1, and it is considered that a useful recycled polyol was obtained in terms of reactivity.

[0104] (2) Examples 3 to 15 (Method for Producing Recycled Polyol (Part 1)) The methods for producing recycled polyols in Examples 3 to 15 satisfy the following requirements (d) to (f). The method for producing recycled polyols in Comparative Example 2 does not satisfy the following requirement (f). Requirement (d): The polyurethane resin is reacted with a decomposition agent to separate it into a polyol phase mainly composed of polyols and an amine phase mainly composed of amine compounds. Requirement (e): React an amine compound with a carboxylic acid compound and recover a composition containing the resulting reaction product. Requirement (f): Add a carboxylic acid and / or an anhydride having two or more carboxyl groups to the composition such that the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in the molecular chain.

[0105] In Comparative Example 2, the hydroxyl value of the regenerated polyol was high, suggesting that the synthesis of the regenerated polyol did not proceed sufficiently. In Comparative Example 2, the total amine value of the regenerated polyol was high, suggesting that the regenerated polyol may have been too reactive. On the other hand, in Examples 3 to 15, the hydroxyl value of the regenerated polyols was lower than that of Comparative Example 2, suggesting that the synthesis of the regenerated polyols proceeded. In Examples 3 to 15, the total amine value of the regenerated polyols was lower than that of Comparative Example 2, and from a reactivity standpoint, it is considered that useful regenerated polyols were obtained.

[0106] Furthermore, among Examples 3 to 15, Examples 8 to 10 satisfy the following requirement (g) in addition to requirements (d) to (f). • Requirement (g): The composition also contains an alkylene oxide adduct and / or an alkanediol of an alcohol.

[0107] In Examples 8 to 10, the recycled polyol was in a liquid state. By satisfying requirement (g), it was possible to obtain a liquid recycled polyol that is easy to use as a recycled raw material.

[0108] 8. Effects of the Examples This embodiment provides a technology for utilizing by-product amine compounds resulting from the decomposition of polyurethane resins.

[0109] This disclosure is not limited to the embodiments detailed above, and various modifications or changes are possible within the scope of this disclosure.

Claims

1. By reacting a decomposition agent with polyurethane resin, the resin is separated into a phase mainly composed of polyols and a phase mainly composed of amine compounds. The amine compound is reacted with a carboxylic acid compound, and the resulting reaction product is collected to obtain a composition containing the product. A method for producing a regenerated polyol, comprising adding a carboxylic acid and / or an anhydride thereof having two or more carboxyl groups to the aforementioned composition such that the ratio of the total molar amount of hydroxyl groups and amino groups in the composition to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain.

2. A method for producing a regenerated polyol according to claim 1, wherein an alkylene oxide adduct of an alcohol and / or an alkanediol is also added to the composition.

3. By reacting a decomposition agent with polyurethane resin, the resin is separated into a polyol phase mainly composed of polyols and an amine phase mainly composed of amine compounds. The amine phase is recovered, A method for producing a regenerated polyol, comprising adding a carboxylic acid and / or an anhydride having two or more carboxyl groups to the amine phase such that the ratio of the total molar amount of hydroxyl groups and amino groups in the amine phase to the molar amount of carboxyl groups derived from the carboxyl groups and the acid anhydride groups of the anhydride is 3 or less, thereby obtaining a regenerated polyol having amide bonds and ester bonds in its molecular chain.

4. The method for producing a regenerated polyol according to claim 3, wherein an alkylene oxide adduct of an alcohol and / or an alkanediol are also added to the amine phase.

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