Poly(hydroxyalkanoate) and methods for preparing the same substance.

Abstract

DEPCT68 This disclosure describes the preparation of poly(hydroxyalkanoate) by oligomerization reaction. This was prepared by polymerizing hydroxyalkanoic acid with a compound containing a hydroxyl group. Two or more carboxyl groups and compounds containing two or more carboxyl groups, which thus makes it... It is possible to prepare poly(hydroxyalkanoate) compounds with a low ratio of vinyl groups in the end groups. Containing compounds with reduced yellowness index (YI) and nitrogen content, as well as those with high molecular weight;

Description

Poly(hydroxyalkanoate) and method for preparing the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0012861, filed January 31, 2023, and Korean Patent Application No. 10-2024-0013786, filed January 30, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to poly(hydroxyalkanoate) and a method for producing the same.

[0004]

[0005] Poly(3-hydroxypropionic acid) has biodegradable properties, and due to these environmentally friendly properties, research on its use has been actively conducted recently.

[0006]

[0007] There are two main methods for producing poly(3-hydroxypropionic acid): one is a petrochemical-based method using β-propiolactone (PL) for polymerization, and the other is a bio-based method using 3-hydroxypropinic acid (3HP).

[0008]

[0009] Since PL requires multiple synthetic steps using ethylene oxide, it has disadvantages in terms of economic feasibility compared to 3HP. Furthermore, poly(3-hydroxypropionic acid) manufactured using PL has a bio-content of 0%, and in particular, because it uses an acrylic acid series with a vinyl group as an initiator, the proportion of vinyl groups in the end groups is high.

[0010]

[0011] Polymerization using 3HP biosynthesis requires multiple steps, including freeze-drying, ultrasonication, and solvent extraction, to obtain poly(3-hydroxypropionic acid), necessitating the use of large quantities of solvent. While the bio-based polymerization yields 100% bio-based poly(3-hydroxypropionic acid), the residual residues after fermentation often result in a high organic nitrogen content and a high YI.

[0012]

[0013] To address this issue, attempts have been made to polycondense 3HP, but the formation of byproducts in the form of cyclic oligomers limits the ability to obtain high-molecular-weight poly(3-hydroxypropionic acid). Attempts have been made to increase molecular weight by ROP of low-molecular-weight cyclic oligomers, but separation and purification are difficult.

[0014]

[0015] Therefore, there is a need for a method for producing poly(3-hydroxypropionic acid) by polycondensation from 3HP, which is high molecular weight but has a low ratio of vinyl groups in the terminal group.

[0016]

[0017] The present invention provides a poly(hydroxyalkanoate) having a high molecular weight, a low ratio of vinyl groups in terminal groups, and a low yellow index (YI) value and nitrogen content.

[0018] In addition, the present invention provides a method for producing the poly(hydroxyalkanoate).

[0019]

[0020] According to one embodiment of the present invention, a poly(hydroxyalkanoate) is provided, which comprises a repeating unit represented by the following chemical formula 1 and / or a repeating unit represented by the following chemical formula 2.

[0021] [Chemical Formula 1]

[0022]

[0023] [Chemical Formula 2]

[0024]

[0025] In the above chemical formulas 1 and 2,

[0026] A, G, Q and R are each independently substituted or unsubstituted alkylene having 1 to 10 carbon atoms,

[0027] X and Y are each independently a substituted or unsubstituted alkylene having 1 to 20 carbon atoms; a substituted or unsubstituted arylene having 6 to 60 carbon atoms; or a substituted or unsubstituted heteroarylene having 2 to 60 carbon atoms containing at least one heteroatom selected from the group consisting of N, O, and S,

[0028] p, q, m and n are each independently integers from 0 to 200,

[0029] p + q is greater than or equal to 1,

[0030] n + m is greater than or equal to 1.

[0031] According to another embodiment of the present invention, there is provided a step (step 1) of preparing a first oligomer by polymerizing a hydroxyalkanoic acid under a compound having two or more hydroxyl groups;

[0032] A step (step 2) of producing a second oligomer by polymerizing a hydroxyalkanoic acid under a compound having two or more carboxyl groups; and

[0033] A method for producing poly(hydroxyalkanoate) is provided, including a step (step 3) of producing poly(hydroxyalkanoate) by polymerizing the first oligomer and the second oligomer.

[0034] Hereinafter, poly(hydroxyalkanoate) and a method for producing poly(hydroxyalkanoate) according to specific embodiments of the invention will be described in more detail.

[0035]

[0036] Furthermore, unless the steps constituting the manufacturing method described herein are explicitly stated to be sequential or consecutive, or there is another special order, the order of one step constituting a manufacturing method from another step is not limited to the order described in the specification. Accordingly, the order of the steps constituting the manufacturing method may be varied within a range readily understandable to those skilled in the art, and in such cases, any subsequent changes apparent to those skilled in the art are within the scope of the present invention.

[0037] In this specification, the terms first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

[0038] In addition, the term "substituted or unsubstituted" in the present specification means a group that is substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium; a halogen group; a nitrile group; a nitro group; a hydroxy group; a carbonyl group; an ester group; an imide group; an amino group; a phosphine oxide group; an alkoxy group; an aryloxy group; an alkylthioxy group; an arylthioxy group; an alkylsulfoxy group; an arylsulfoxy group; a silyl group; a boron group; an alkyl group; a cycloalkyl group; an alkenyl group; an aryl group; an aralkyl group; an aralkenyl group; an alkylaryl group; an alkylamine group; an aralkylamine group; a heteroarylamine group; an arylphosphine group; or a heterocyclic group containing at least one of N, O, and S atoms, or a substituted or unsubstituted group in which two or more substituents among the above-mentioned substituents are linked. For example, the "substituent linked by two or more substituents" may be a biphenyl group. That is, the biphenyl group can be an aryl group or can be interpreted as a substituent in which two phenyl groups are connected.

[0039] In this specification, the number of carbon atoms in the carbonyl group is not particularly limited, but is preferably 1 to 40 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

[0040]

[0041] In the present specification, the ester group may have the oxygen of the ester group replaced by a straight-chain, branched-chain or cyclic alkyl group having 1 to 25 carbon atoms or an aryl group having 6 to 25 carbon atoms. Specifically, the ester group may be a compound having the following structural formula, but is not limited thereto.

[0042]

[0043] In this specification, the number of carbon atoms in the imide group is not particularly limited, but is preferably 1 to 25 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

[0044]

[0045] In the present specification, the silyl group specifically includes, but is not limited to, a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, etc.

[0046] In this specification, the boron group specifically includes, but is not limited to, a trimethyl boron group, a triethyl boron group, a t-butyldimethyl boron group, a triphenyl boron group, a phenyl boron group, etc.

[0047] In this specification, examples of halogen groups include fluorine, chlorine, bromine, or iodine.

[0048] In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to one embodiment, the number of carbon atoms of the alkyl group is 1 to 20. According to another embodiment, the number of carbon atoms of the alkyl group is 1 to 10. According to another embodiment, the number of carbon atoms of the alkyl group is 1 to 6. Specific examples of alkyl groups include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohectylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, Examples include, but are not limited to, 4-methylhexyl and 5-methylhexyl.

[0049] In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to one embodiment, the number of carbon atoms in the alkenyl group is 2 to 20. According to another embodiment, the number of carbon atoms in the alkenyl group is 2 to 10. According to another embodiment, the number of carbon atoms in the alkenyl group is 2 to 6. Specific examples include, but are not limited to, vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-(naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbenyl, and styrenyl.

[0050] In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms. According to one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 20 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specifically, examples thereof include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like.

[0051] In the present specification, the aryl group is not particularly limited, but preferably has 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the aryl group has 6 to 30 carbon atoms. According to one embodiment, the aryl group has 6 to 20 carbon atoms. The monocyclic aryl group may be, but is not limited to, a phenyl group, a biphenyl group, a terphenyl group, etc. The polycyclic aryl group may be, but is not limited to, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, etc.

[0052] In the present specification, the fluorenyl group may be substituted, and two substituents may combine with each other to form a spiro structure. When the fluorenyl group is substituted,

[0053]

[0054] It can be, but is not limited to, the following.

[0055] In the present specification, a heteroaryl group is a heterocyclic group that contains at least one of O, N, Si, and S as a heteroatom and has aromaticity, and the number of carbon atoms is not particularly limited, but is preferably 2 to 60 carbon atoms. Examples of heteroaryl groups include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, acridyl group, pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, isoquinoline group, indole group, carbazole group, benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, thiazolyl group, isoxazolyl group, Examples include, but are not limited to, oxadiazolyl group, thiadiazolyl group, benzothiazolyl group, phenothiazinyl group, and dibenzofuranyl group.

[0056] In this specification, the aryl group among the aralkyl group, the aralkenyl group, the alkylaryl group, and the arylamine group is the same as the examples of the aryl group described above. In this specification, the alkyl group among the aralkyl group, the alkylaryl group, and the alkylamine group is the same as the examples of the alkyl group described above. In this specification, the heteroaryl among the heteroarylamine may be applied to the description of the heterocyclic group described above. In this specification, the alkenyl group among the aralkenyl group is the same as the examples of the alkenyl group described above. In this specification, the description of the aryl group described above may be applied to the arylene except that it is a divalent group. In this specification, the description of the heterocyclic group described above may be applied to the heteroarylene except that it is a divalent group. In this specification, the description of the aryl group or the cycloalkyl group described above may be applied to the hydrocarbon ring except that it is not a monovalent group but is formed by combining two substituents. In the present specification, the description of the heterocyclic group described above may be applied, except that the heterocyclic group is not monovalent and is formed by combining two substituents.

[0057] In addition, unless otherwise stated herein, the weight average molecular weight of the first oligomer, the second oligomer, poly(hydroxyalkanoate), poly(3-hydroxypropionic acid), etc. can be measured using gel permeation chromatography (GPC). Specifically, the oligomer or (co)polymer is dissolved in chloroform to a concentration of 2 mg / mL, 20 μL is injected into the GPC, and GPC analysis is performed at 40°C. At this time, chloroform is used as the mobile phase of the GPC, and the flow rate is 1.0 mL / min. Two Agilent Mixed-B columns are connected in series, and an RI Detector is used as the detector. The Mw value is derived using a calibration curve formed using a polystyrene standard sample. Nine weight-average molecular weights of polystyrene standard specimens were used: 2,000 g / mol, 10,000 g / mol, 30,000 g / mol, 70,000 g / mol, 200,000 g / mol, 700,000 g / mol, 2,000,000 g / mol, 4,000,000 g / mol, and 10,000,000 g / mol.

[0058]

[0059] According to one embodiment of the invention, a poly(hydroxyalkanoate) comprising a repeating unit represented by the following chemical formula 1 and / or a repeating unit represented by the following chemical formula 2 may be provided.

[0060] [Chemical Formula 1]

[0061]

[0062] [Chemical Formula 2]

[0063]

[0064] In the above chemical formulas 1 and 2,

[0065] A, G, Q and R are each independently substituted or unsubstituted alkylene having 1 to 10 carbon atoms,

[0066] X and Y are each independently a substituted or unsubstituted alkylene having 1 to 20 carbon atoms; a substituted or unsubstituted arylene having 6 to 60 carbon atoms; or a substituted or unsubstituted heteroarylene having 2 to 60 carbon atoms containing at least one heteroatom selected from the group consisting of N, O, and S,

[0067] p, q, m and n are each independently integers from 0 to 200,

[0068] p + q is greater than or equal to 1,

[0069] n + m is greater than or equal to 1.

[0070]

[0071] In the above chemical formulas 1 and 2, A, G, Q and R may be the same or different, and may be, for example, an unsubstituted alkylene having 2 to 5 carbon atoms or an alkyl group-substituted alkylene having 2 to 5 carbon atoms.

[0072] For example, the above A, G, Q and R can each independently be ethylene, propylene, butylene, pentylene, methyl-substituted ethylene, methyl-substituted propylene, methyl-substituted butylene, methyl-substituted pentylene, ethyl-substituted ethylene, ethyl-substituted propylene, ethyl-substituted butylene or ethyl-substituted pentylene.

[0073] In addition, the poly(hydroxyalkanoate) may be a polymer obtained by polymerizing 3-hydroxypropionic acid, which is an eco-friendly monomer derived from bio, and in this case, A, G, Q, and R may be ethylene. The poly(3-hydroxypropionate) obtained by polymerizing 3-hydroxypropionic acid has the characteristics of lowering the proportion of terminal groups while implementing a high molecular weight by including a repeating unit represented by the above-described chemical formula 1 and / or a repeating unit represented by the following chemical formula 2.

[0074]

[0075] In the above chemical formulas 1 and 2, X and Y may be the same or different, and for example, X and Y may be a substituted or unsubstituted alkylene having 1 to 10 carbon atoms or a substituted or unsubstituted arylene having 6 to 20 carbon atoms.

[0076] In addition, the X and Y may each independently be unsubstituted C2-C7 ethylene; C2-C5 alkyl-substituted alkylene; C6-C20 unsubstituted arylene; or C6-C20 alkyl-substituted arylene. For example, the X and Y may each independently be ethylene, propylene, butylene, pentylene, hexylene, heptylene, phenylene, biphenylene, triphenylene, naphthalene, anthracenylene, etc.

[0077] In the above chemical formulas 1 and 2, p, q, n, and m may be the same or different, and for example, p, q, n, and m may each independently be 0 to 200, 1 to 200, 2 to 180, 3 to 150, 5 to 120, 10 to 100, 15 to 80, or 20 to 60.

[0078] Also, p + q can be greater than or equal to 1, and n + m can be greater than or equal to 1.

[0079] Meanwhile, in the above chemical formulas 1 and 2, * indicates a connection point.

[0080]

[0081] In the past, it was difficult to achieve high molecular weight due to problems such as the formation of by-products in the process of manufacturing poly(hydroxyalkanoate) such as poly(3-hydroxypropionic acid), and in addition, during the polymerization of hydroxyalkanoate such as 3-hydroxypropionic acid manufactured in a bioprocess, a large amount of organic nitrogen was included in the polymer due to the inclusion of fermentation residues, resulting in a high yellow index (YI).

[0082] However, the poly(hydroxyalkanoate) according to the above embodiment may include a repeating unit represented by the above chemical formula 1, or may include a repeating unit represented by the above chemical formula 2, or may include both a repeating unit represented by the above chemical formula 1 and a repeating unit represented by the above chemical formula 2, and accordingly, while enabling implementation of a high molecular weight, the yellow index (YI) value and nitrogen content may also be low.

[0083] In addition, when the poly(hydroxyalkanoate) contains only repeating units represented by the chemical formula 1, the degree of polymerization of the repeating units represented by the chemical formula 1 may be 20 to 3000, 50 to 2000, 100 to 1800, 180 to 1700, or 300 to 1500.

[0084] In addition, when the poly(hydroxyalkanoate) contains only repeating units represented by the chemical formula 2, the degree of polymerization of the repeating units represented by the chemical formula 2 may be 20 to 3000, 50 to 2000, 100 to 1800, 180 to 1700, or 300 to 1500.

[0085] In addition, when the poly(hydroxyalkanoate) includes a repeating unit represented by the chemical formula 1 and a repeating unit represented by the chemical formula 2 together, the degree of polymerization of each repeating unit may be 1 to 1000, 10 to 900, 50 to 800, 80 to 700, or 100 to 500, and the ratio of the degree of polymerization of the repeating unit represented by the chemical formula 1 to the degree of polymerization of the repeating unit represented by the chemical formula 2 may be 1:0.01 to 100, 1:0.1 to 50, 1:0.2 to 20, 1:0.3 to 10, 1:0.5 to 5, or 1:1 to 3.

[0086]

[0087] In addition, poly(hydroxyalkanoate) may have a hydroxyl group, a carboxyl group, a vinyl group, etc. as terminal groups. Conventionally, during the polymerization of hydroxyalkanoate such as 3-hydroxypropionic acid, a vinyl group is generated as a side reaction at the terminal. The vinyl group acts as a factor that breaks the equivalence ratio of each functional group (hydroxyl group, carboxyl group) in important polycondensation, thereby inhibiting the reaction rate and making it difficult to obtain a polymer having a high molecular weight. However, the poly(hydroxyalkanoate) according to the above embodiment may contain a small number of vinyl groups at the terminals while including the repeating units of the above chemical formulas 1 and / or 2 by being manufactured by the manufacturing process described below.

[0088] For example, the poly(hydroxyalkanoate) may have a ratio of vinyl groups among the terminal groups of 20 mol% or less, 19 mol% or less, 18 mol% or less, 17 mol% or less, 16 mol% or less, or 15 mol% or less. In addition, the poly(hydroxyalkanoate) is better the lower the ratio of vinyl groups among the terminal groups, and for example, the ratio of vinyl groups among the terminal groups may be 0.1 mol% or more, 0.2 mol% or more, 0.3 mol% or more, 0.4 mol% or more, or 0.5 mol% or more.

[0089]

[0090] Additionally, the poly(hydroxyalkanoate) may include a hydroxyl terminal group and / or a carboxyl terminal group. For example, the poly(hydroxyalkanoate) may include at least one hydroxyl terminal group selected from terminal groups represented by the following chemical formulae 3 to 5.

[0091] [Chemical Formula 3]

[0092]

[0093] [Chemical Formula 4]

[0094]

[0095] [Chemical Formula 5]

[0096]

[0097] In the above chemical formulas 3 to 5,

[0098] Descriptions of A, G, X, p and q are as described above.

[0099] The proportion of the hydroxyl group terminal group in the entire terminal of the poly(hydroxyalkanoate) may be from 50% to 99%, for example from 55% to 95%, from 60% to 90%, from 65% to 85%, or from 70% to 80%.

[0100]

[0101] Additionally, the poly(hydroxyalkanoate) may include at least one carboxyl group terminal group selected from terminal groups represented by the following chemical formulas 6 to 8.

[0102] [Chemical Formula 6]

[0103]

[0104] [Chemical Formula 7]

[0105]

[0106] [Chemical Formula 8]

[0107]

[0108] In the above chemical formulas 6 to 8,

[0109] Descriptions of Q, R, Y, n and m are as described above.

[0110] The proportion of the carboxyl group terminal group in the entire terminal of the poly(hydroxyalkanoate) may be from 50% to 99%, for example from 55% to 95%, from 60% to 90%, from 65% to 85%, or from 70% to 80%.

[0111]

[0112] Additionally, the poly(hydroxyalkanoate) may further include a repeating unit represented by the following chemical formula 9.

[0113] [Chemical Formula 9]

[0114]

[0115] In the above chemical formula 9,

[0116] Descriptions of A, G, R, X and Y are as described above.

[0117] b, c and d can each independently be an integer from 1 to 200, for example from 3 to 150, from 5 to 120, from 10 to 100, from 15 to 80, or from 20 to 60.

[0118] The degree of polymerization of the repeating unit represented by the chemical formula 9 in the above poly(hydroxyalkanoate) may be 1 to 1000, 10 to 900, 50 to 800, 80 to 700, or 100 to 500.

[0119] In addition, the ratio of the degree of polymerization of the repeating unit represented by the above chemical formula 1 and the degree of polymerization of the repeating unit represented by the above chemical formula 9 may be 1:0.05 to 10, 1:0.1 to 8, 1:0.2 to 5, or 1:0.3 to 1.

[0120] In addition, the ratio of the degree of polymerization of the repeating unit represented by the above chemical formula 2 and the degree of polymerization of the repeating unit represented by the above chemical formula 9 may be 1:0.05 to 10, 1:0.1 to 8, 1:0.2 to 5, or 1:0.3 to 1.

[0121]

[0122] Additionally, the poly(hydroxyalkanoate) may have a yellow index (YI) value of 30 or less and a nitrogen content of 30 ppm or less.

[0123] For example, the poly(hydroxyalkanoate) may have a yellow index (YI) value of 30 or less, 28 or less, 26 or less, 23 or less, 20 or less, 15 or less, or 14 or less. In addition, the poly(hydroxyalkanoate) is better the lower the yellow index value, and for example, the yellow index value may be 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more.

[0124] Additionally, the poly(hydroxyalkanoate) may have a nitrogen content of 60 ppm or less, 55 ppm or less, 50 ppm or less, or 45 ppm or less. Additionally, the poly(hydroxyalkanoate) is better the lower the nitrogen content, and for example, the nitrogen content may be 0.1 ppm or more, 0.2 ppm or more, 0.3 ppm or more, 0.4 ppm or more, or 0.5 ppm or more.

[0125]

[0126] In addition, the poly(hydroxyalkanoate) may have an acid value of 10 meq / kg or more and 300 meq / kg or less. For example, the poly(hydroxyalkanoate) may have an acid value of 20 meq / kg or more and 250 meq / kg or less, 30 meq / kg or more and 200 meq / kg or less, 40 meq / kg or more and 180 meq / kg or less, 50 meq / kg or more and 160 meq / kg or less, or 60 meq / kg or more and 150 meq / kg or less.

[0127] Additionally, the poly(hydroxyalkanoate) may have a bio-content of 90% or more, 92% or more, 95% or more, 98% or more, or 100%.

[0128]

[0129] Additionally, the weight average molecular weight of the poly(hydroxyalkanoate) may be 15,000 to 200,000. Preferably, the weight average molecular weight of the poly(hydroxyalkanoate) may be 16,000 or more, 17,000 or more, 18,000 or more, 19,000 or more, or 20,000 or more, and 150,000 or less, 100,000 or less, 90,000 or less, 80,000 or less, 70,000 or less, 69,000 or less, 68,000 or less, 67,000 or less, 66,000 or less, 65,000 or less, 64,000 or less, 63,000 or less, 62,000 or less, 61,000 or less, or 60,000 or less.

[0130] Additionally, the number average molecular weight of the poly(hydroxyalkanoate) may be 10,000 to 100,000. Preferably, the number average molecular weight of the poly(hydroxyalkanoate) may be 11,000 or more, 12,000 or more, 13,000 or more, 14,000 or more, or 15,000 or more, and 90,000 or less, 80,000 or less, 70,000 or less, 60,000 or less, 50,000 or less, 40,000 or less, or 30,000 or less.

[0131] Additionally, the molecular weight distribution (Mw / Mn) of the poly(hydroxyalkanoate) may be 1.5 to 3.5. Preferably, the molecular weight distribution of the poly(hydroxyalkanoate) may be 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, or 2.0 or more, and 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, or 3.0 or less.

[0132]

[0133] According to another embodiment of the present invention, there is provided a step (step 1) of producing a first oligomer by polymerizing a hydroxyalkanoic acid under a compound having two or more hydroxyl groups;

[0134] A step (step 2) of producing a second oligomer by polymerizing a hydroxyalkanoic acid under a compound having two or more carboxyl groups; and

[0135] A method for producing poly(hydroxyalkanoate) is provided, including a step (step 3) of producing poly(hydroxyalkanoate) by polymerizing the first oligomer and the second oligomer.

[0136] The above hydroxyalkanoic acid is not limited thereto, but may be 3-hydroxypropionic acid, 4-hydroxybutanoic acid, 5-hydroxypentanoic acid, 6-hydroxyhexanoic acid, and, for producing a poly(hydroxyalkanoate) with a high biocarbon content, may be 3-hydroxypropionic acid, and in particular, may be a bio-derived 3-hydroxypropionic acid produced in a bioprocess.

[0137]

[0138] The method for producing poly(hydroxyalkanoate) according to the above other embodiments can provide poly(hydroxyalkanoate) having a high molecular weight, a low ratio of vinyl groups in terminal groups, and a low yellow index (YI) value and nitrogen content by producing poly(hydroxyalkanoate) through steps 1 to 3.

[0139]

[0140] The above step 1 is a step of producing a first oligomer by polymerizing a hydroxyalkanoic acid in the presence of a compound having two or more hydroxyl groups. The polymerization reaction may be a melt polymerization reaction, and melt polymerization means that the reactant hydroxyalkanoic acid and the product hydroxyalkanoic acid oligomer remain in a liquid state. In addition, the first oligomer produced by polymerizing the hydroxyalkanoic acid in the presence of the compound having two or more hydroxyl groups may be represented by the following chemical formula 10.

[0141] [Chemical Formula 10]

[0142]

[0143] In the above chemical formula 10,

[0144] Descriptions of A, G, X, p and q are as described above.

[0145] In addition, the first oligomer manufactured in step 1 may have a weight average molecular weight of 1,000 or more and 20,000 or less. Preferably, the weight average molecular weight of the first oligomer may be 1,500 or more, 2,000 or more, 2,500 or more, or 3,000 or more, and 15,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, or 70,000 or less.

[0146]

[0147] The compound having two or more hydroxyl groups can be represented by the following chemical formula 12.

[0148] [Chemical Formula 12]

[0149]

[0150] In the above chemical formula 12,

[0151] The description of the above X is as described above.

[0152] Additionally, the compound having two or more hydroxyl groups may be 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, catechol, hydroquinone, resorcinol, etc.

[0153] The amount of the compound having two or more hydroxyl groups may be from 0.1 to 20.0 parts by weight, from 0.5 to 10.0 parts by weight, from 1.0 to 8.0 parts by weight, or from 1.5 to 5.0 parts by weight, based on 100 parts by weight of the hydroxyalkanoic acid. If the amount of the compound having two or more hydroxyl groups is used too little, it becomes impossible to control the reaction conditions by adjusting the input ratio, and if the amount of the compound having two or more hydroxyl groups is used too much, the ratio of the hydroxyalkanoic acid in the final polymerized poly(hydroxyalkanoate) polymer becomes too small, which causes a problem of deterioration in the physical properties.

[0154]

[0155] The above step 1 can be carried out at a temperature of 50° C. or more and 150° C. or less and a pressure of 1 torr or more and 200 torr or less. For example, the reaction temperature of the above step 1 can be 60° C. or more, 70° C. or more, 80° C. or more, 85° C. or more, or 90° C. or more, and 140° C. or less, 130° C. or less, 120° C. or less, 110° C. or less, or 100° C. or less. In addition, the above step 1 can be carried out under a pressure of 2 torr or more, 5 torr or more, 10 torr or more, or 15 torr or more, and 150 torr or less, 130 torr or less, 110 torr or less, 100 torr or less, or 80 torr or less. In addition, the reaction time of the above step 1 can be appropriately considered in consideration of the molecular weight, yield, etc. of the first oligomer produced, and is preferably performed for 1 to 10 hours, 2 to 8 hours, or 3 to 5 hours.

[0156] Additionally, the above step 1 can be carried out in the presence of a sulfonic acid catalyst. The sulfonic acid catalyst is, for example, p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, or p-xylene-2-sulfonic acid. The catalyst can be used in an amount of 0.1 to 0.5 mol% or 0.2 to 0.4 mol% relative to the hydroxyalkanoic acid.

[0157]

[0158] In addition, the step 1 may further include a step of drying the hydroxyalkanoic acid before the polymerization reaction. For example, the drying temperature may be 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, or 90°C or higher, and 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower. In addition, the drying may be performed under a pressure of 10 torr or higher, 20 torr or higher, 30 torr or higher, or 40 torr or higher, and 760 torr or lower, 500 torr or lower, 400 torr or lower, 300 torr or lower, or 200 torr or lower.

[0159]

[0160] The above step 2 is a step of producing a second oligomer by polymerizing a hydroxyalkanoic acid in the presence of a compound having two or more carboxyl groups. The polymerization reaction may be a melt polymerization reaction. In addition, the second oligomer produced by polymerizing the hydroxyalkanoic acid in the presence of the compound having two or more carboxyl groups may be represented by the following chemical formula 11.

[0161] [Chemical Formula 11]

[0162]

[0163] In the above chemical formula 11,

[0164] Descriptions of Q, R, Y, n and m are as described above.

[0165] In addition, the second oligomer manufactured in step 2 may have a weight average molecular weight of 1,000 or more and 20,000 or less. Preferably, the weight average molecular weight of the second oligomer may be 1,500 or more, 2,000 or more, 2,500 or more, or 3,000 or more, and 15,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, or 70,000 or less.

[0166] The compound having two or more carboxyl groups can be represented by the following chemical formula 13.

[0167] [Chemical Formula 13]

[0168]

[0169] In the above chemical formula 5,

[0170] The description of the above Y is as described above.

[0171] Additionally, the compound having two or more carboxyl groups may be succinic acid, adipic acid, isophthalic acid, terephthalic acid, etc.

[0172] The amount of the compound having two or more carboxyl groups may be from 0.1 to 20.0 parts by weight, from 0.5 to 10.0 parts by weight, from 1.0 to 8.0 parts by weight, or from 1.3 to 5.0 parts by weight, based on 100 parts by weight of the hydroxyalkanoic acid. If the amount of the compound having two or more carboxyl groups is used too little, it becomes impossible to control the reaction conditions by adjusting the input ratio, and if the amount of the compound having two or more carboxyl groups is used too much, the ratio of the hydroxyalkanoic acid in the final polymerized poly(hydroxyalkanoate) polymer becomes too small, which causes a problem of deterioration in physical properties.

[0173] The above step 2 can be carried out at a temperature of 50° C. or more and 150° C. or less and a pressure of 1 torr or more and 200 torr or less. For example, the reaction temperature of the above step 2 can be 60° C. or more, 70° C. or more, 80° C. or more, 85° C. or more, or 90° C. or more, and 140° C. or less, 130° C. or less, 120° C. or less, 110° C. or less, or 100° C. or less. In addition, the above step 2 can be carried out under a pressure of 2 torr or more, 5 torr or more, 10 torr or more, or 15 torr or more, and 150 torr or less, 130 torr or less, 110 torr or less, 100 torr or less, or 80 torr or less. In addition, the reaction time of step 2 can be appropriately considered in consideration of the molecular weight, yield, etc. of the second oligomer produced, and is preferably performed for 1 to 10 hours, 2 to 8 hours, or 3 to 5 hours.

[0174] Additionally, the above step 2 can be carried out in the presence of a sulfonic acid catalyst. The sulfonic acid catalyst is, for example, p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, or p-xylene-2-sulfonic acid. The catalyst can be used in an amount of 0.1 to 0.5 mol%, or 0.2 to 0.4 mol%, relative to 3-hydroxypropionic acid.

[0175]

[0176] In addition, the step 2 may further include a step of drying the hydroxyalkanoic acid before the polymerization reaction. For example, the drying temperature may be 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, or 90°C or higher, and 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower. In addition, the drying may be performed under a pressure of 10 torr or higher, 20 torr or higher, 30 torr or higher, or 40 torr or higher, and 760 torr or lower, 500 torr or lower, 400 torr or lower, 300 torr or lower, or 200 torr or lower.

[0177]

[0178] Step 3 above is a step of producing poly(hydroxyalkanoate) by polymerizing the first oligomer and the second oligomer. A poly(hydroxyalkanoate) other than the above-described embodiment can be produced by step 3 above.

[0179] In the above step 3, the first oligomer may be used in an amount of 0.1 to 10 times, 0.2 to 5 times, or 0.3 to 3 times, relative to the second oligomer. If the first oligomer is used in an excessively small or excessive amount relative to the second oligomer, there is a problem in that the balance of functional groups is not balanced, making it impossible to obtain a poly(3-hydroxypropionic acid) having a high molecular weight.

[0180] The above step 3 can be carried out at a temperature of 70°C or higher and 150°C or lower. The reaction temperature of the above step 3 can be 75°C or higher, 80°C or higher, 85°C or higher, 90°C or higher, or 95°C or higher, and 140°C or lower, 130°C or lower, 120°C or lower, 110°C or lower, or 100°C or lower. In addition, the pressure of step 3 may be 5 mbar or less, 4 mbar or less, 3 mbar or less, 2 mbar or less, 1 mbar or less, 0.5 mbar or less, 0.4 mbar or less, or 0.3 mbar or less, and 0.01 mbar or more, 0.02 mbar or more, 0.03 mbar or more, 0.04 mbar or more, 0.05 mbar or more, 0.06 mbar or more, 0.07 mbar or more, 0.08 mbar or more, 0.09 mbar or more, or 0.1 mbar or more. The reaction time of step 3 may be appropriately considered in consideration of the molecular weight, yield, etc. of the polymer to be produced, and is preferably performed for 1 to 60 hours, 5 to 50 hours, 10 to 40 hours, or 15 to 30 hours.

[0181] Meanwhile, since step 3 is performed subsequent to steps 1 and 2, the catalyst added in each of steps 1 and 2 can also participate in the reaction in step 3.

[0182]

[0183] As described above, the present invention can produce poly(hydroxyalkanoate) by polycondensing hydroxyalkanoic acid under specific conditions, thereby producing poly(hydroxyalkanoate) having a high molecular weight, a low ratio of vinyl groups in terminal groups, and a low yellow index (YI) value and nitrogen content.

[0184]

[0185] Hereinafter, embodiments of the present invention will be described in more detail in the following examples. However, the following examples are merely illustrative of embodiments of the present invention, and the content of the present invention is not limited by the following examples.

[0186]

[0187] Example 1

[0188] (1) Preparation of the first oligomer

[0189] 60 g of 3-hydroxypropionic acid and 2.5 g of 1,3-propanediol were charged into oil bath reactor A, and then p-toluenesulfonic acid (p-TSA) catalyst (0.4 mol% based on 3-hydroxypropionic acid) was charged into oil bath reactor A, and a polymerization reaction was performed at 90 ℃ and 10 torr for 2 hours, and then at 0.2 torr for 2 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain the first oligomer (weight average molecular weight: 3,000 g / mol).

[0190] (2) Manufacturing of second oligomer

[0191] 60 g of 3-hydroxypropionic acid and 0.8 g of succinic acid were charged into oil bath reactor B, and then p-toluenesulfonic acid (p-TSA) catalyst (0.4 mol% based on 3-hydroxypropionic acid) was charged into oil bath reactor B, and polymerization was performed at 90 ℃ and 10 torr for 2 hours, and then at 0.2 torr for 2 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain a second oligomer (weight average molecular weight: 7,000 g / mol).

[0192] (3) Manufacturing of poly(3-hydroxypropionic acid)

[0193] 6 g of the first oligomer and 16 g of the second oligomer were charged into oil bath reactor C, and a polymerization reaction was performed at 110°C and 0.2 torr for 24 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain poly(3-hydroxypropionic acid).

[0194]

[0195] Example 2

[0196] (1) Poly(3-hydroxypropionic acid) was manufactured in the same manner as Example 1, except that 60 g of 3-hydroxypropionic acid and 1.0 g of 1,3-propanediol were added to oil bath reactor A during the manufacture of the first oligomer.

[0197]

[0198] Example 3

[0199] (3) Poly(3-hydroxypropionic acid) was manufactured in the same manner as Example 1, except that 10 g of the first oligomer and 18 g of the second oligomer were added to the oil bath reactor C when manufacturing poly(3-hydroxypropionic acid).

[0200]

[0201] Example 4

[0202] (3) Poly(3-hydroxypropionic acid) was manufactured in the same manner as in Example 2, except that 12 g of the first oligomer and 14 g of the second oligomer were added to the oil bath reactor C when manufacturing poly(3-hydroxypropionic acid).

[0203]

[0204] Example 5

[0205] 60 g of 3-hydroxypropionic acid and 2.5 g of 1,3-propanediol were charged into oil bath reactor A, and then p-toluenesulfonic acid (p-TSA) catalyst (0.4 mol% based on 3-hydroxypropionic acid) was charged into oil bath reactor A, and a polymerization reaction was performed at 90 ℃ and 10 torr for 2 hours, and then at 0.2 torr for 2 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain the first oligomer (weight average molecular weight: 3,000 g / mol). 20 g of the first oligomer was polymerized at 110 ℃ and 0.2 torr for 24 hours. After the reaction was completed, the reactant was dissolved in chloroform and extracted with methanol to obtain poly(3-hydroxypropionic acid).

[0206]

[0207] Comparative Example 1

[0208] β-Propiolactone (19.4 ml) was added to the reactor, and then acrylic acid (10 uL, 0.05 mol%) and Sn(Oct)2 (9 uL, 0.01 mol%) were added and reacted at 100°C for 1 hour to produce a polymer.

[0209]

[0210] Comparative Example 2

[0211] A polymer was manufactured with reference to Korean Patent Publication No. 10-2021-0037448. Specifically, the culture medium used was MR (Modified Riesenberg) medium containing ampicillin at a concentration of 0.2 g / L, and a 5 L fermenter (internal volume: 3 L) was used. As a microorganism for fermentation, a recombinant vector was used by transforming XL1-Blue Escherichia coli with a recombinant vector in which the RecC gene, a polyhydroxyalkanoate synthase (PHA synthase) derived from Ralstonia eutropha, and the CPCT_540 gene, a mutant of propionyl-CoA transferase derived from Clostridium propionicum, were cloned into the pBLuescript II KS+ vector. The above CPPCT_540 gene is an improved gene in which the base sequence was substituted to express the 193rd amino acid, Valine, as Alanine (V194A), and three silent mutations (T669C, A1125G, T1158C) were made, which only resulted in DNA substitution without amino acid changes (WO 09 / 022797). Poly(3-hydroxypropionic acid) was fermented and produced by continuously adding a feeding solution containing antibiotics and glucose at a concentration of 700 g / L to the MR medium throughout the fermentation.

[0212]

[0213] Comparative Example 3

[0214] 3-Hydroxypropionic acid (60 g) from which moisture had been removed was placed in a reactor, and 0.2 mol% of p-TSA (p-Toluenesulfonic acid) as a catalyst based on 3-hydroxypropionic acid and 0.1 mol% of tin(II) chloride (SnCl2) based on 3-hydroxypropionic acid were added. The temperature and pressure inside the reactor were maintained at 90°C and 10 torr, respectively, for 2 hours to produce a 3-hydroxypropionic acid oligomer.

[0215] Next, the temperature and pressure in the reactor were adjusted to 110°C and 0.2 torr, respectively, and the reaction was performed for 8 hours to produce poly(3-hydroxypropionate).

[0216]

[0217] Comparative Example 4

[0218] 3-Hydroxypropionic acid (60 g) from which moisture had been removed was placed in a reactor, and 0.4 mol% of p-TSA (p-Toluenesulfonic acid) as a catalyst based on 3-hydroxypropionic acid and 0.2 mol% of tin(II) chloride (SnCl2) based on 3-hydroxypropionic acid were added. The temperature and pressure inside the reactor were maintained at 90°C and 10 torr, respectively, for 2 hours to produce a 3-hydroxypropionic acid oligomer.

[0219] Next, the temperature and pressure in the reactor were adjusted to 110°C and 0.2 torr, respectively, and the reaction was performed for 8 hours to produce poly(3-hydroxypropionate).

[0220]

[0221] Experimental example

[0222] The properties of the polymers manufactured in the above examples and comparative examples were evaluated using the following method, and the results are shown in Table 1 below.

[0223]

[0224] 1. Weight average molecular weight, number average molecular weight, and molecular weight distribution

[0225] For each polymer manufactured in the above examples and comparative examples, the weight average molecular weight, number average molecular weight, and polydispersity index were measured by gel permeation chromatography (GPC: gel permeation chromatography, Waters Alliance e2695).

[0226] - Solvent: chloroform (eluent)

[0227] - Flow rate: 1.0 ml / min

[0228] - Column temperature: 40℃

[0229] - Standard: Polystyrene

[0230]

[0231] 2. Analysis of vinyl groups at the terminal end

[0232] The ratio of vinyl groups to total end groups was calculated by 1H-NMR measurement using a Buker 500MHz NMR model. Specifically, each polymer was dissolved in d-CDCl3 at a concentration of 8 mg / ml and measured, and the calculation was performed using the following mathematical formula 1.

[0233] [Mathematical Formula 1]

[0234]

[0235] In the above mathematical formula 1,

[0236] a is the area value of 1H of C=C at 6.3 ppm,

[0237] b is the area value of 2H of HO-CH2- at 3.8 ppm.

[0238]

[0239] 3. Yield analysis

[0240] The yields for the polymers manufactured in the above examples and comparative examples were calculated using the following mathematical formula 2. Meanwhile, the yield of comparative example 2 refers to the proportion of poly(3-hydroxypropionic acid) contained within the cells.

[0241] [Equation 2]

[0242] {Final polymer content (g) / Content of 3-hydroxypropionic acid used as a reactant (g)} * 100

[0243]

[0244] 4. Biocontent analysis

[0245] The polymers manufactured in the above examples and comparative examples were analyzed for biocontent using ASTM 6866-22. Specifically, the samples were graphitized for accelerator mass spectrometry (AMS) analysis and then radioisotope 14 The content of C (bio-derived) was analyzed using ASTM 6866-22.

[0246]

[0247] 5. Yellow Index Analysis

[0248] For the polymers manufactured in the above examples and comparative examples, the yellow index (YI) was measured using a colorimeter from NIPPON DENSHOKU.

[0249] - Light source type: D65

[0250] - Field of view: 10 °

[0251]

[0252] 6. Nitrogen content analysis

[0253] For the polymers manufactured in the above examples and comparative examples, 10 mg of sample was injected and burned at a temperature of 800°C using NSX N-Quant equipment to analyze the total nitrogen (N) content.

[0254]

[0255] 7. Polymer acid value analysis

[0256] For the polymers manufactured in the above examples and comparative examples, the titration point was analyzed by titrating 0.02 N potassium methoxide solution as a titration solution using a DGi 116-solvent electrode in a Mettler Toledo T5 device.

[0257]

[0258] MnMwPDIVinyl group content(%)Yield(%)Bio content(%)Yellow index(YI)Nitrogen(N)Content(ppm)Acid value(meq / kg)Example 114200266001.9138810011.543148.6Example 216700326002.0158510013.440140.9Example 314900299002.0178810011.145143.4Example 417600377002.2198210012.540112.8Example 5270063002.387810010.84139Comparative example 127500490001.784487011.840103.4 Comparative Example 2---N.D1710029.73566068.1 Comparative Example 37000109001.6338310013.045280.6 Comparative Example 414800258001.7628310011.143156.1

[0259] Referring to Table 1 above, it was confirmed that Examples 1 to 4 exhibited high molecular weight and yield, but had a low vinyl group content of 19% or less, and had low yellow index, nitrogen content, and acid value. On the other hand, Example 5 had a high yield, low vinyl group content, low yellow index, nitrogen content, and acid value, but did not include the step 2 process of polymerizing 3-hydroxypropionic acid under dicarboxylic acid, and thus had a lower molecular weight than Examples 1 to 4.

[0260] Meanwhile, Comparative Example 1, in which poly(3-hydroxypropionic acid) was produced using β-propiolactone, was confirmed to have a high vinyl group content and no biocarbon content. In addition, Comparative Example 2, in which poly(3-hydroxypropionic acid) was produced using a fermentation process, was confirmed to have low yield and problems with high yellow index and nitrogen content. Furthermore, Comparative Examples 3 and 4 were confirmed to have lower molecular weights and higher vinyl group content and acid values ​​compared to the examples.

Claims

DEPCT681. Poly(hydroxyalkanoate) composed of repeating units represented by the following chemical formula 1 and / or repeating units represented by the following chemical formula 2: [Chemical Formula 1](Chemical Formula)[Chemical Formula 2](Chemical Formula) where in Chemical Formulas 1 and 2, each group A, G, Q, and R are independently substituted or unsubstituted alkylenes with 1 to 10 carbon atoms; each group X and Y are independently substituted or unsubstituted alkylenes with 1 to 20 carbon atoms; substituted or unsubstituted arylene with 6 to 60 carbon atoms; or substituted or unsubstituted heteroarylene with 2 to 60 carbon atoms with at least one heteroatom selected from a group consisting of N, O, and S; each independent p, q, m, and n are integers from 0 to 200; p+q is 1 or more; and n+m is 1 or more than 2.Poly(hydroxyalkanoate) according to claim 1, in which the poly(hydroxyalkanoate) has at least one hydroxyl terminal group chosen from the terminal groups represented by the following chemical formulas 3 to 5: [chemical formula 3](chemical formula)[chemical formula 4](chemical formula)[chemical formula 5](chemical formula), in which in chemical formulas 3 to 5, A, G, X, p and q are as defined in claim 13. Poly(hydroxyalkanoate) according to claim 1, in which the poly(hydroxyalkanoate) has at least one carboxyl terminal group chosen from the terminal groups represented by the following chemical formulas 3 to 5: It is represented by the following chemical formulas 6 to 8: [Chemical Formula 6](Chemical Formula)[Chemical Formula 7](Chemical Formula)[Chemical Formula 8](Chemical Formula), where in chemical formulas 6 to 8, Q, R, Y, n, and m are as defined in claim 14. Poly(hydroxyalkanoate) according to claim 2, where the ratio of hydroxyl terminal groups to all terminal groups of poly(hydroxyalkanoate) is 50% to 99%.

5. Poly(hydroxyalkanoate) according to claim 3, where the ratio of carboxyl terminal groups to all terminal groups of poly(hydroxyalkanoate) is 50% to 99%. 6.Poly(hydroxyalkanoate) according to claim 1, in which the poly(hydroxyalkanoate) is further composed of repeating units represented by the following chemical formula 9: [chemical formula 9](chemical formula), in which in chemical formula 9, A, G, R, X, and Y are as defined in claim 1, and b, c, and d each independently are integers of 1 to 2007. Poly(hydroxyalkanoate) according to claim 1, in which the poly(hydroxyalkanoate) has a vinyl ratio in all end groups of 20% or less, a yellowness index (YI) of 30 or less, a nitrogen content of 60 ppm or less, and an acidity of 10 milliequivalents / kg or greater and 300 milliequivalents / kg or less8.The method for preparing poly(hydroxyalkanoate) consists of: (Step 1) polymerization of hydroxyl alkanoic acid in the presence of a compound containing two or more hydroxyl groups to prepare the type one oligomer; (Step 2) polymerization of hydroxyl alkanoic acid in the presence of a compound containing two or more carboxyl groups to prepare the type two oligomer; and (Step 3) polymerization of the type one and type two oligomers to prepare the poly(hydroxyalkanoate).9Method for the preparation of poly(hydroxyalkanoate) pursuant to claim 8, where the first oligomer is composed of repeating units represented by the following chemical formula 10: [chemical formula 10](chemical formula), where in chemical formula 10, each group A and G are independently substituted or unsubstituted alkylenes with 1 to 10 carbon atoms; X is a substituted or unsubstituted alkylene with 1 to 20 carbon atoms; substituted or unsubstituted arylene with 6 to 60 carbon atoms; or substituted or unsubstituted heteroarylene with 2 to 60 carbon atoms with at least one heteroatom selected from a group consisting of N, O and S; each independent p and q are integers from 0 to 200; and p+q is 1 or greater than 10.Method for the preparation of poly(hydroxyalkanoate) pursuant to claim 8, whereby the second oligomer is composed of repeating units represented by the following chemical formula 11: [chemical formula 11](chemical formula), whereby in chemical formula 11, each group Q and R independently is a substituted or unsubstituted alkylene with 1 to 10 carbon atoms; Y is a substituted or unsubstituted alkylene with 1 to 20 carbon atoms; a substituted or unsubstituted arylene with 6 to 60 carbon atoms; or hetylene. Substituted or non-substituted aroarylene containing 2 to 60 carbon atoms with at least one heteroatom selected from a group consisting of N, O, and S, n and m each independently sampled as integers of 0 to 200, and n+m is 1 or greater.

11. Method for the preparation of poly(hydroxyalkanoate) pursuant to claim 8, in which the first and second oligomers each independently have a weight-average molecular weight of 1,000 or greater and 20,000 or less.12.Method for the preparation of poly(hydroxyalkanoates) according to claim 8, where compounds containing two or more hydroxyl groups are represented by the following chemical formula 12: [chemical formula 12]HO-X-OH, where in chemical formula 12, X is a substituted or unsubstituted alkylene containing 1 to 20 carbon atoms; a substituted or unsubstituted arylene containing 6 to 60 carbon atoms; or a substituted or unsubstituted heteroarylene containing 2 to 60 carbon atoms with at least one heteroatom selected from the group consisting of N, O and S13. Method for the preparation of poly(hydroxyalkanoates) according to claim 8, where compounds containing two or more carboxyl groups are denoted by the following chemical formula 13 [chemical formula 13] HOOC-Y-COOH, where in chemical formula 13, Y is a substituted or unsubstituted alkylene containing 1 to 20 carbon atoms; a substituted or unsubstituted arylene containing 6 to 60 carbon atoms; or a substituted or unsubstituted heteroarylene containing 2 to 60 carbon atoms with at least one heteroatom selected from the group consisting of N, O and S14.Method for the preparation of poly(hydroxyalkanoates) according to claim 8, where in step 1, a compound containing two or more hydroxyl groups is used in an amount of 0.1 to 20 parts by weight on the basis of 100 parts by weight of hydroxylalkanoic acid.

15. Method for the preparation of poly(hydroxyalkanoates) according to claim 8, where in step 2, a compound containing two or more carboxyl groups is used in an amount of 0.1 to 20 parts by weight on the basis of 100 parts by weight of hydroxylalkanoic acid.

16. Method for the preparation of poly(hydroxyalkanoate) pursuant to claim 8, in which steps 1 and 2 are incorporated, drying of hydroxyalkanoic acid prior to polymerization reaction.

17. Method for the preparation of poly(hydroxyalkanoate) pursuant to claim 8, in which steps 1 and 2 are performed at temperatures of 50 °C or more and 150 °C or less under pressures of 1 Torr or more and 200 Torr or less. 18.Methods for the preparation of poly(hydroxyalkanoates) according to claim 8, where steps 1 and 2 are performed in the presence of a sulfonic acid-based catalyst.

19. Methods for the preparation of poly(hydroxyalkanoates) according to claim 8, where in step 3, the first oligomer is used in an amount of 0.1 times or more and 10 times or less of the amount of the second oligomer.

20. Methods for the preparation of poly(hydroxyalkanoates) according to claim 8, where step 3 is performed at temperatures of 70°C or more and 150°C or less.