Giblock copolymer

Abstract

To provide a novel diblock copolymer comprising a polyester and a polyamide.SOLUTION: A diblock copolymer comprises a block containing a polyester and a block containing a polyamide and is represented by a following formula (1) (where p is an integer of 2-3; q is an integer of 1-10; r is an integer of 1-11; s is an integer of 3-11; t is an integer of 3-11; x is an integer of 1-60; y is an integer of 0-120; R1 represents an optionally substituted aromatic hydrocarbon group or a C1-20 alkyl group; and R2 represents an optionally substituted aromatic hydrocarbon group, a C1-6 alkyl group, or a C1-6 alkyloxy group).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a diblock copolymer, and particularly to a diblock copolymer for compatibilizing a polyester resin and / or a polyamide resin.

Background Art

[0002] Due to concerns about environmental problems caused by plastic products that are consumed and produced in large quantities, expectations for biodegradable plastics that are decomposed in the natural environment are increasing. In this regard, aliphatic polyesters are used in fibers, films, nonwoven fabrics, etc. because they have good biodegradability, excellent hydrolysis resistance, and practical mechanical strength. However, depending on the application, the melting point and mechanical strength may be insufficient. On the other hand, polyamide is used as one of the engineering plastics because it has excellent characteristics such as high heat resistance, high mechanical strength, and chemical resistance. Also, certain polyamides are known to be biodegradable by microorganisms in soil or activated sludge (see Patent Document 1). Therefore, by compounding an aliphatic polyester and a polyamide, it is expected that the mechanical properties and processability can be adjusted according to the application, and a composite material having biodegradability can be obtained.

[0003] Since aliphatic polyester and polyamide are incompatible resins, there are cases where a compatibilizer is added to obtain a homogeneous composite material (see Patent Documents 2 and 3). However, in the method of crosslinking resins with the reactive compatibilizer described in Patent Document 2, there is a risk that properties such as biodegradability and flexibility may be impaired in the composite material. Also, in the method of using a functional group-modified aromatic polyester as a compatibilizer as in Patent Document 3, since the compatibilizer has a functional group different from the resin with which it is compounded, there is also a risk that properties such as the biodegradability and mechanical strength of the composite material may be impaired.

[0004] To avoid these concerns, the use of a diblock copolymer composed of an aliphatic ester block and an amide block as a compatibilizer is considered. The diblock copolymer is expected to reduce the interfacial free energy between the resins and act as a so-called surfactant, resulting in an easy obtainment of a homogeneous composite material.

[0005] When using, for example, an ester - amide exchange reaction between a polyester and a polyamide to obtain a diblock copolymer of the polyester and the polyamide, since all of the ester and amide bonds in the main chain can be reaction sites, the chain lengths of the ester block and the amide block, and the number of repetitions of each block in one polymer chain cannot be controlled, and thus a diblock copolymer cannot be obtained (see Patent Document 4). Also, when using a method by ring - opening polymerization of a cyclic ester or a cyclic amide, theoretically a diblock copolymer is considered to be obtainable due to the difference in the polymerization mechanisms of each raw material, but it is known that the actual product is a random block copolymer (see Non - Patent Document 1). On the other hand, when a cyclic amide is allowed to act after first forming an ester block, an "insertion" mechanism in which the ester site is cleaved and the ring - opened amide is introduced in between has been proposed, and again a diblock copolymer cannot be obtained (see Non - Patent Document 2). In addition, since polyamide is poorly soluble in many organic solvents such as toluene and tetrahydrofuran generally used for ring - opening polymerization, when an amide block is formed first, the available synthetic methods are limited (see Non - Patent Documents 3 and 4).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non - Patent Documents

[0007] [Non-Patent Document 1] EUR.Polym.J.1984,20,549-557. [Non-Patent Document 2] React.Funct.Polym.2008,68,1392-1407. [Non-Patent Document 3] Prog.Polym.Sci.2000,25,1411-1462. [Non-Patent Document 4] EUR.Polym.J.2018,98,83-93. [Summary of the Invention] [Problems to be Solved by the Invention]

[0008] In view of the above points, an object of the present invention is to provide a novel diblock copolymer composed of polyester and polyamide. [Means for Solving the Problems]

[0009] As a result of intensive studies to solve the conventional problems, the present inventors have found that, compared with the existing technology, the chain lengths of the ester block and the amide block can be adjusted, and a diblock copolymer in which the amide block and the ester block are bonded in a 1:1 ratio can be selectively produced, and thus the present invention has been completed. That is, the present invention includes the following aspects: One aspect of the present invention is 〔1〕A diblock copolymer comprising a block containing polyester and a block containing polyamide, which is represented by the following formula (1). [Chemical Formula] (In formula (1), p is an integer from 2 to 3, q is an integer from 1 to 10, r is an integer from 1 to 11, s is an integer from 3 to 11, t is an integer from 3 to 11, x is an integer from 1 to 60, and y is an integer from 0 to 120. R1 represents an aromatic hydrocarbon group which may have a substituent, or an alkyl group having 1 to 20 carbon atoms, and R2 represents an aromatic hydrocarbon group which may have a substituent, an alkyl group having 1 to 6 carbon atoms, or an alkyloxy group having 1 to 6 carbon atoms.) In another aspect of the present invention [2] A surfactant comprising the diblock copolymer described in [1] above. Here, the surfactant of the present invention, in one embodiment [3] A surfactant comprising the diblock copolymer described in [1] above, characterized in that it is a surfactant for compatibilizing aliphatic polyesters and polyamide resins. In another aspect of the present invention, [4] A method for producing the diblock copolymer described in [1] above, a compound represented by the following formula (2) containing a polyester [Chemical formula] (In formula (2), R1 represents an aromatic hydrocarbon group which may have a substituent, or an alkyl group having 1 to 20 carbon atoms, p is an integer from 2 to 3, q is an integer from 1 to 10, r is an integer from 1 to 11, and x is an integer from 1 to 60.) a compound represented by the following formula (3) containing a polyamide [Chemical formula] (In formula (3), s is an integer from 3 to 11, t is an integer from 3 to 11, and y is an integer from 0 to 120. R2 represents an aromatic hydrocarbon group which may have a substituent, an alkyl group having 1 to 6 carbon atoms, or an alkyloxy group having 1 to 6 carbon atoms.) and a step of bonding between the amino group in the compound represented by the formula (2) and the carboxy group in the compound represented by the formula (3), relates to a production method. [Effect of the Invention]

[0010] The diblock copolymer of the present invention has a surfactant action. Therefore, according to the diblock copolymer of the present invention, it can be used, for example, as a compatibilizer for aliphatic polyester resins and polyamide resins. [Brief Description of the Drawings]

[0011]

Figure 1

[0012] One aspect of the present invention provides a diblock copolymer comprising a block containing polyester and a block containing polyamide, which is represented by the following formula (1). [Chemical Formula] (In formula (1), p is an integer from 2 to 3, q is an integer from 1 to 10, r is an integer from 1 to 11, s is an integer from 3 to 11, t is an integer from 3 to 11, x is an integer from 1 to 60, and y is an integer from 0 to 120. R1 represents an aromatic hydrocarbon group which may have a substituent or an alkyl group having 1 to 20 carbon atoms, and R2 represents an aromatic hydrocarbon group which may have a substituent, an alkyl group having 1 to 6 carbon atoms, or an alkyloxy group having 1 to 6 carbon atoms.)

[0013] In one embodiment, in formula (1), p, q, r, s, t, x, and y are arbitrary integers selected from the ranges shown below. p represents an integer of 2 to 3, more preferably 2. q represents an integer of 1 to 10, more preferably 2 to 6. r represents an integer of 1 to 11, more preferably 2 to 6. s and t represent integers of 3 to 11, more preferably 3 to 6. x represents an integer of 1 to 60, more preferably 1 to 30. y represents an integer of 0 to 120, more preferably 1 to 100.

[0014] In this specification, the "aromatic hydrocarbon group" is preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms, and although not limited to the following, benzene can be cited as an example. Examples of the aromatic hydrocarbon group having a substituent include those in which part or all of the hydrogen groups on the aromatic ring are substituted with an alkyl group, an allyl group, a carboxyalkyl group, a halogen group, a cyano group, a nitro group, etc., and although not limited to the following, a benzene ring substituted with 1 to 5 methyl groups can be cited as an example. Examples of the "alkyl group" as a substituent for the aromatic hydrocarbon group include linear or branched alkyl groups having 1 to 20 carbon atoms. Examples of the "carboxyalkyl group" as a substituent for the aromatic hydrocarbon group include linear or branched alkyl groups having 1 to 20 carbon atoms substituted with a carboxyl group such as carboxymethyl, carboxyethyl, carboxyisopropyl, etc. Examples of the "halogen group" as a substituent for the aromatic hydrocarbon group include fluorine, chlorine, bromine, etc.

[0015] In this specification, the "alkyl group" includes linear or branched alkyl groups, and examples thereof include a methyl group, an ethyl group, and an isopropyl group.

[0016] In this specification, examples of the "alkyloxy group" include a methoxy group, an ethoxy group, and a tert-butyloxy group.

[0017] One embodiment of the diblock copolymer according to the present invention is a compound represented by the following formula (2). [Chemical formula] (In formula (4), x is an integer from 1 to 60, and y is an integer from 0 to 120.)

[0018] The number average molecular weight of such a diblock copolymer is, for example, 0.3 to 30 kDa, preferably 1 to 20 kDa.

[0019] The diblock copolymer according to the present invention is a diblock copolymer in which a polyester block and a polyamide block are bonded in a 1:1 ratio. More specifically, it is a diblock copolymer in which a block containing polybutylene succinate and a block containing polyamide 4 are bonded in a 1:1 ratio. Therefore, the diblock copolymer according to the present invention has a surfactant action. One aspect of the present invention provides a surfactant containing the diblock copolymer represented by formula (1). The surfactant of the present invention can be used, for example, for compatibilizing an aliphatic polyester resin and a polyamide resin. In this specification, an aliphatic polyester resin is a polymer in which aliphatic alkyl chains are linked by ester bonds, and examples thereof include polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, polycaprolactone, etc. Also, in this specification, a polyamide resin is a polymer having an amide bond, and examples thereof include poly(2-pyrrolidone) (nylon 4), polycapramide (nylon 6), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene sebacamide (nylon 610), etc. By using the surfactant containing the diblock copolymer according to the present invention, a composite material in which an aliphatic polyester resin and a polyamide resin are uniformly compatibilized can be obtained. Since the cross-linking of the resins is not performed, the biodegradability of the composite material is not impaired.

[0020] One aspect of the present invention is a method for producing the diblock copolymer according to the present invention, comprising: a compound represented by the following formula (2) containing a polyester and [Chemical formula] (In formula (2), R1 represents an aromatic hydrocarbon group which may have a substituent or an alkyl group having 1 to 20 carbon atoms, p is an integer of 2 to 3, q is an integer of 1 to 10, r is an integer of 1 to 11, and x is an integer of 1 to 60.) A compound represented by the following formula (3) containing polyamide [Chemical formula] (In formula (3), s is an integer of 3 to 11, t is an integer of 3 to 11, y is an integer of 0 to 120. R2 represents an aromatic hydrocarbon group which may have a substituent, an alkyl group having 1 to 6 carbon atoms, or an alkyloxy group having 1 to 6 carbon atoms.) Provided is a production method including a step of bonding the compound represented by the formula (2) and the compound represented by the formula (3) between the amino group in the compound represented by the formula (2) and the carboxy group in the compound represented by the formula (3).

[0021] Note that the terminal amino group of the compound represented by formula (2) may be in a salt form such as hydrochloride, sulfate, nitrate, etc. As an embodiment of the compound represented by formula (2), a compound represented by the following formula (5) can be mentioned. [Chemical formula] (In formula (5), x is an integer of 1 to 60.)

[0022] The ratio of the compound represented by formula (2) and the compound represented by formula (3) used in the reaction can be a molar ratio of 3:1 to 1:3.

[0023] The reaction is preferably carried out in the presence of a condensing agent. Specific examples of the condensing agent that can be used in the reaction include, but are not limited to, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM), (1-cyano-2-ethoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), and the like. The amount of the condensing agent used can be 1 to 5 molar equivalents relative to the carboxyl group in the compound represented by formula (3).

[0024] As the solvent used in the reaction, it is preferable to use a solvent that can dissolve both the polyester described in formula (2) and the polyamide described in formula (3). Specifically, but not limited to, N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide, and the like can be mentioned.

[0025] It is preferable to add salts to the solvent to promote the dissolution of the polyamide. Specifically, lithium chloride, lithium bromide, lithium iodide, calcium chloride, and the like can be mentioned. The salt can be added at a concentration of 10 to 200 g / L with respect to the solvent. -1 of the solvent.

[0026] A base can be added to the reaction as necessary for the activation of the amine terminus. Specifically, triethylamine, N,N-diisopropylethylamine, pyridine, 2,6-lutidine, 2,4,6-collidine, N,N-dimethylaminopyridine (DMAP), and the like can be mentioned. The addition amount of the base can be 0.1 to 100 molar equivalents relative to the amino group of the compound represented by formula (2).

[0027] The reaction can be carried out under conditions of about 0 to 150 °C. More preferably, the temperature is about 80 to 120 °C. The reaction time can be carried out under conditions of 0.5 to 6.0 hours.

[0028] The solution after the reaction is dropped into a water / acetone mixed solvent to obtain a precipitate. By washing, filtering, and drying the obtained precipitate, the target diblock copolymer can be obtained. Specifically, the obtained precipitate is dispersed in a methanol solution containing 10% calcium chloride, and then pure water is added and recovered by filtration. Next, it is sequentially washed with pure water and acetone, dispersed in chloroform, and after adding acetone, it is filtered to obtain a precipitate. The obtained precipitate can be recovered as a white solid by vacuum drying.

[0029] The compound represented by formula (2) can be obtained by substituting the OH terminal of the compound (OH-PEs) represented by formula (6) with an NH2 terminal.

Chemical formula

[0030] To substitute the OH terminal of the compound (OH-PEs) represented by formula (6) with an NH2 terminal, although not limited to the following, for example, it can be obtained by introducing an N-Boc group on the OH terminal side and then removing the Boc group.

[0031] The introduction of the N-Boc group can be carried out, for example, by reacting the compound (OH-PEs) represented by formula (6) with an N-Boc protected amino acid to introduce the N-Boc group. Specific examples of the N-Boc protected amino acid include N-Boc-glycine, N-Boc-β-alanine, N-Boc-4-aminobutyric acid, N-Boc-5-aminovaleric acid, N-Boc-6-aminohexanoic acid, N-Boc-7-aminoheptanoic acid, and the like. In this reaction, it is preferable to react OH-PEs and N-Boc protected amino acids in a molar ratio of 1:1 to 1:5.

[0032] For this reaction, solvents such as dichloromethane, chloroform, or a mixed solvent thereof can be used. As the condensing agent, a carbodiimide-based condensing agent can be used, and examples include N,N-diisopropylcarbodiimide (DIC), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide (EDCI), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDCI·HCl), and the like. The amount of the condensing agent used can be 1 to 5 molar equivalents relative to the N-Boc protected amino acid.

[0033] As the condensation auxiliary agent for this reaction, N,N-dimethylaminopyridine (DMAP), 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole can be added as needed. The addition amount of the condensation auxiliary agent can be about 0 to 2 molar equivalents relative to the N-Boc protected amino acid.

[0034] This reaction can be carried out under conditions of about -20 to 60 °C. More preferably, the temperature is about 0 to 40 °C. The reaction time can be carried out under conditions of 1 to 3 hours. After the reaction, the reaction solution obtained is added with pure water to stop the reaction, and then through the processes of concentration, washing and drying, the compound (N-Boc-PEs) represented by the formula (7) can be obtained as a white solid.

Chemical formula

[0035] In addition, the removal of the Boc group of N-Boc-PEs can be carried out according to known methods, and can be removed by adding a strong acid such as trifluoroacetic acid in the absence of a solvent or in the presence of a solvent such as dichloromethane. Further, by subjecting this to base treatment with sodium hydrogen carbonate or the like, the compound represented by formula (2) can be obtained. Alternatively, it can be obtained in the form of a salt by further neutralizing the terminal amino group with an aqueous hydrochloric acid solution or the like.

[0036] The compound (OH-PEs) represented by formula (6) can be produced by the reaction of a monohydric alcohol and a hydroxycarboxylic acid represented by formula (8).

Chemical formula

[0037] The monohydric alcohol used in the reaction step is not particularly limited, and for example, primary alcohols such as methanol, ethanol, 1-propanol, 1-butanol, and glycols with one end substituted such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monophenyl ether, 4-(benzoyloxy)-1-butanol can be used.

[0038] The mixing ratio of the monohydric alcohol and the hydroxycarboxylic acid used in the reaction step can be 1:1 to 1:60 molar ratio. Since the monohydric alcohol acts as a terminal capping agent for the self-condensation of the hydroxycarboxylic acid, the degree of polymerization of the polyester block can be adjusted by appropriately selecting the mixing ratio.

[0039] As the solvent in the reaction step, halogen-based organic solvents such as dichloromethane, chloroform, dichloroethane, or a mixed solvent thereof can be used.

[0040] As the condensing agent in this reaction, a carbodiimide-based condensing agent can be used. For example, N,N-diisopropylcarbodiimide (DIC), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide (EDCI), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDCI·HCl), etc. can be mentioned. Also, the usage amount of the condensing agent can be about 1 to 5 molar equivalents relative to the hydroxycarboxylic acid.

[0041] As the condensation auxiliary agent in this reaction, N,N-dimethylaminopyridine (DMAP), 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole can be added as needed. The addition amount of the condensation auxiliary agent can be about 0 to 2 molar equivalents relative to the hydroxycarboxylic acid.

[0042] This reaction can be carried out under conditions of about -20 to 60 °C. More preferably, it is at a temperature of about 0 to 40 °C. The reaction time can be carried out under conditions of 1 to 3 hours. After the reaction, the reaction solution obtained is added with pure water to stop the reaction, and then through the concentration and drying steps, the compound (OH-PEs) represented by the formula (6) can be obtained as a white solid.

[0043] The compound (hydroxycarboxylic acid) represented by the formula (8) can be produced by the reaction of a dihydric alcohol and a cyclic anhydride.

[0044] There is no particular limitation on the dihydric alcohol used in this reaction step, and examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, etc.

[0045] Examples of the cyclic anhydride used in this reaction step include succinic anhydride, glutaric anhydride, phthalic anhydride, maleic anhydride, etc.

[0046] The reaction ratio of the cyclic anhydride and the dihydric alcohol can be 1:1 to 1:100 in molar ratio.

[0047] As the solvent in the reaction step, dichloromethane, chloroform, tetrahydrofuran, toluene, N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide, or a mixed solvent thereof can be used.

[0048] For this reaction, a basic catalyst can be added to promote the reaction. Specifically, triethylamine, N,N-diisopropylethylamine, pyridine, 2,6-lutidine, 2,4,6-collidine, N,N-dimethylaminopyridine (DMAP), etc. can be mentioned. The addition amount of the base can be 0 to 100 molar equivalents relative to the cyclic anhydride.

[0049] The compound represented by formula (3) is obtained by subjecting the acyl lactam and cyclic lactam represented by formula (9) to ring-opening polymerization in the presence of a base and then hydrolyzing the terminal lactam.

Chemical formula

[0050] As the cyclic lactam, a cyclic lactam having 3 to 11 carbon atoms can be used, and without being limited thereto, specifically, 2-pyrrolidone, ε-caprolactam, ω-octalactam, ω-laurin lactam, etc. can be mentioned.

[0051] The compounding ratio of the acyl lactam and cyclic lactam represented by formula (9) used in the reaction can be 1:1 to 1:120 in molar ratio. Since the acyl lactam acts as an initiator for ring-opening polymerization, the degree of polymerization of the polyamide block can be adjusted by appropriately selecting the compounding ratio.

[0052] As the base, metal alkoxides such as sodium tert-butoxide and potassium tert-butoxide, and metal salts of cyclic lactams used in polymerization reactions such as sodium 2-pyrrolidone can be used. The amount of the base used can be 0.01 to 1 molar equivalent relative to the cyclic lactam.

[0053] The reaction is preferably carried out under an inert gas such as argon gas.

[0054] The reaction can be carried out under conditions of about 0 to 70 °C. More preferably, the temperature is about 0 to 40 °C. The reaction time can be carried out under conditions of 1 to 24 hours. The solid obtained after the reaction is dissolved in concentrated hydrochloric acid or the like to hydrolyze the terminal lactam, and then through a concentration and drying process, the compound (COOH-PA) represented by the formula (4) can be obtained as a white solid.

[0055] The acyl lactam represented by the formula (9) can be synthesized by a condensation reaction according to a known method from the corresponding lactam or its derivative and a carboxylic acid or its derivative.

[0056] Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the embodiments.

Examples

[0057] (Synthesis of NH2-PEs) (Synthesis of 4-(benzoyloxy)-1-butanol)

Chemical formula

[0058] <Synthesis of Hydroxycarboxylic Acid>

Chem.

[0059] <Synthesis of OH-PEs>

Chem.

[0060] <Synthesis of N-BocPEs>

Chemical formula

[0061] <Synthesis of NH2-PEs hydrochloride>

Chemical formula

[0062] (Synthesis of COOH-PA) (Synthesis of acyl lactam) [Chemical formula] Pyridine (47 mL, 581.00 mmol) and 2-pyrrolidone (16 mL, 210.00 mmol) were added to a 200 mL eggplant flask and dissolved, and then cooled to 0 °C. Benzoyl chloride (23 mL, 200.00 mmol) was slowly added dropwise to the reaction mixture, and the mixture was stirred at 0 °C for 4 hours. 200 mL of 2 M aqueous hydrochloric acid solution was added to the reaction mixture to stop the reaction, and 100 mL of ethyl acetate was added for extraction. The extraction was performed twice in total. The recovered organic layer was successively washed with 100 mL of pure water and 100 mL of saturated brine, dried over sodium sulfate, and concentrated using a rotary evaporator. The residue was purified by recrystallization in a solvent system of ethyl acetate / hexane = 1:4 to obtain acyl lactam as a pale yellow solid (yield 29.20 g, yield rate 77%).

[0063] (Synthesis of COOH-PA) [Chemical formula] 100 mL eggplant flask was charged with potassium tert-butoxide (0.22 g, 2.00 mmol) and thoroughly purged with argon gas. On the other hand, 1-benzoyl-2-pyrrolidone (1.89 g, 10.00 mmol) and 2-pyrrolidone (7.6 mL, 100.00 mmol) were added to another 20 mL eggplant flask and completely dissolved. The resulting solution was poured into the 100 mL eggplant flask containing the above potassium tert-butoxide and stirred at 30 °C. The solution solidified within 5 minutes and the stirring stopped, but the reaction was continued for 3.5 hours as it was. 15 mL of concentrated hydrochloric acid was added to the solid after the reaction and dissolved overnight. The resulting solution was concentrated on a rotary evaporator, 20 mL of 2,2,2-trifluoroethanol was added for azeotropic distillation, and again 20 mL of 2,2,2-trifluoroethanol was added to obtain a homogeneous solution. The resulting solution was dropped into 500 mL of a mixed solution of pure water:acetone = 1:9, and the resulting precipitate was collected and dried under vacuum to obtain COOH-PA as a white solid (yield 6.41 g, yield 61%). 1 It was calculated that y = 10 from 1H-NMR.

[0064] (Synthesis of PEs-PA diblock copolymer) [Chemical formula] In a 10 mL eggplant flask, COOH-PA (0.22 g, 0.21 mmol), diisopropylethylamine (0.06 g, 0.45 mmol), lithium chloride (0.05 g), and N,N-dimethylacetamide (2 mL) were added, and the mixture was heated to 60 °C to obtain a homogeneous solution. The mixture was allowed to cool to room temperature, and COMU (0.10 g, 0.22 mmol) was added, followed by stirring at room temperature for 0.5 h. NH2-PEs hydrochloride (0.25 g, 0.09 mmol) was added thereto to obtain a suspension. The resulting solution became a homogeneous and transparent solution by heating to 100 °C. After the reaction was continued for 3 h, the reaction solution was dropped into 50 mL of a mixed solution of water:acetone = 1:9 to obtain a precipitate. The obtained precipitate was well dispersed in 10 mL of a methanol solution containing 10% calcium chloride, 40 mL of pure water was added, and then the precipitate was collected by filtration. The precipitate was washed successively with 50 mL of pure water and 50 mL of acetone. The obtained precipitate was vacuum dried to obtain the PEs-PA diblock copolymer as a white solid (yield 0.28 g, yield 81%). The obtained PEs-PA diblock copolymer was 1 Analyzed by 1H-NMR, phenyl group terminals derived from PEs and PA were observed in a 1:1 ratio. Also, from the proton peak area ratio between the terminals and inside the block structure, x = 17 and y = 10 were calculated (Figure 1). In Figure 1, for comparison, the 1 1H-NMR analysis results of COOH-PA and NH2-PEs are also shown.

[0065] (Evaluation of surface activity) 1 mL of a mixed solvent of ethylene glycol / pure water = 1:1 containing 25% lithium chloride was added with 1 mL of chloroform, and then samples were added in the amounts shown in Table 1. The obtained two-layer liquid was shaken at a rotation speed of 2000 rpm for 30 seconds using a shaker (AS ONE, test tube mixer TRIOHM-1N). After allowing the solution to stand at room temperature for 24 hours, the presence or absence of an emulsion was visually confirmed. As a result, it was revealed that only when the PEs-PA diblock copolymer described in the examples was added, the emulsion state was maintained even after 24 hours, indicating that the PEs-PA diblock copolymer has surfactant properties. Note that the ethylene glycol / pure water mixed solution containing lithium chloride dissolves COOH-PA but does not dissolve NH2-PEs. On the other hand, chloroform is a solvent that dissolves NH2-PEs but does not dissolve COOH-PA.

[0066]

Table 1

Claims

1. A diblock copolymer comprising a block containing polyester and a block containing polyamide, which is represented by the following formula (1). 【Chemical 1】 (In formula (1), p is an integer from 2 to 3, q is an integer from 1 to 10, r is an integer from 1 to 11, s is an integer from 3 to 11, t is an integer from 3 to 11, x is an integer from 1 to 60, and y is an integer from 0 to 120. R １ and R ２ represent an aromatic hydrocarbon group which may have a substituent.)

2. A surfactant comprising the diblock copolymer according to Claim 1.

3. A surfactant comprising the diblock copolymer according to Claim 1, which is A surfactant for compatibilizing a polyester resin and a polyamide resin.

4. A method for producing a diblock copolymer comprising a block containing polyester and a block containing polyamide, which is represented by the following formula (1), comprising 【Chemical 1】 a compound represented by the following formula (2) containing polyester and 【Chemical 2】 a compound represented by the following formula (3) containing polyamide 【Chemical Formula 3】 and a step of bonding between the amino group in the compound represented by the formula (2) and the carboxy group in the compound represented by the formula (3). (In formula (1) to formula (3), p is an integer of 2 to 3, q is an integer of 1 to 10, r is an integer of 1 to 11, s is an integer of 3 to 11, t is an integer of 3 to 11, x is an integer of 1 to 60, y is an integer of 0 to 120, R1 represents an aromatic hydrocarbon group which may have a substituent, or an alkyl group having 1 to 20 carbon atoms, and R2 represents an aromatic hydrocarbon group which may have a substituent, an alkyl group having 1 to 6 carbon atoms, or an alkyloxy group having 1 to 6 carbon atoms.)

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