Branched poly(3-hydroxypropionic acid) polymer

Abstract

The present invention relates to a branched poly(3-hydroxypropionic acid) polymer which is biodegradable, can have a high molecular weight, and is advantageous for industrial applications.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application Nos. 10-2022-0146011, filed on November 4, 2022, 10-2022-0146014, filed on November 4, 2022, 10-2023-0031735, filed on March 10, 2023, and 10-2023-0150442, filed on November 3, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a novel branched poly(3-hydroxypropionic acid) polymer.

Background Art

[0003] Poly(3-hydroxypropionic acid) is a biodegradable polymer that not only has the property of being difficult to break, but also has excellent mechanical properties and is attracting attention as an environmentally friendly material.

[0004] Generally, poly(3-hydroxypropionic acid) is produced by polycondensing the monomer 3-hydroxypropionic acid (3-HP). Considering the potential for industrial applications, it is necessary to produce poly(3-hydroxypropionic acid) with excellent thermal stability. However, the ester structure is contained in the chain of poly(3-hydroxypropionic acid), and since the thermal decomposition temperature of the ester structure is about 220°C, there is a limit to improving the thermal stability.

[0005] To improve thermal stability, one might consider producing high molecular weight poly(3-hydroxypropionate). However, increasing the molecular weight of the polymer through condensation polymerization of the monomer 3-hydroxypropionic acid is not easy. For example, during the condensation polymerization process, dehydration may occur, converting the monomer reaction ends to vinyl groups and terminating the polymerization. Alternatively, low molecular weight cyclic structures may be generated during the condensation polymerization process, leading to problems such as increased viscosity.

[0006] In addition, with 3HP polymers, there is a problem in that the high acid value reduces polymer stability, making copolymer formation difficult.

[0007] Therefore, there is a need to produce polymers that possess biodegradable properties, have potential for industrial applications, have high production yields, and have an appropriate level of acid value. [Overview of the project] [Problems that the invention aims to solve]

[0008] One objective of this application is to provide a biodegradable branched poly(3-hydroxypropionic acid) polymer.

[0009] Another object of this application is to provide a high molecular weight branched poly(3-hydroxypropionic acid) polymer.

[0010] Another object of this invention is to provide poly(3-hydroxypropionic acid) polymers that are advantageous for industrial applications.

[0011] Another object of this application is to provide a method for producing the branched poly(3-hydroxypropionic acid) polymer. [Means for solving the problem]

[0012] This specification provides branched poly(3-hydroxypropionic acid) polymers and methods for producing the same.

[0013] When producing biodegradable polymers (3HP) by direct condensation polymerization of 3HP, increasing the molecular weight is not easy. This is because the aforementioned side reactions occur during condensation polymerization. However, increasing the molecular weight of polymers is highly relevant to industrial applications, so research in this area is necessary.

[0014] In this regard, the inventors have confirmed that when using the polyfunctional compounds described later, it is possible to easily increase the molecular weight, and that it is easy to control the molecular weight for industrial applications.

[0015] Specifically, the polymer of chemical formula 1, described later, can be produced through an ester reaction between a polyfunctional compound with tetravalent or higher valency and 3-hydroxypropionic acid (3HP). However, using a polyfunctional compound with tetravalent or higher valency that can adequately provide reaction sites (cite) can provide sufficient polymerization and an increase in molecular weight (compared to the case where a compound with trivalent or lower valency is used).

[0016] If the molecular weight of a polymer is insufficient, it may be difficult to fully exhibit its properties, and therefore, in industrial applications, it must be considered that the polymer be mixed with other types of polymers. However, the polymer of chemical formula 1 of this application, which contains units derived from polyfunctional compounds with four or more valents, can have a high molecular weight and can therefore be used on its own.

[0017] Furthermore, according to specific embodiments, by controlling the content of polyfunctional compounds and 3-hydroxypropionic acid that react with each other under predetermined reaction conditions within a predetermined range, polymers with molecular weights of various grades can be provided, thereby broadening the range of industrial applications of the polymer. In addition, since the polymer of this application has a low acid value, it has high polymer stability and is advantageous for the formation of copolymers by additional reactions with other compounds.

[0018] The following provides a more detailed explanation of specific examples of the present invention.

[0019] First, in this specification, the term “substituted or unsubstituted” means a substituent that is substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium; halogen groups; nitrile groups; nitro groups; hydroxyl groups; carbonyl groups; ester groups; imide groups; amino groups; phosphine oxide groups; alkoxy groups; aryloxy groups; alkylthiooxy groups; arylthiooxy groups; alkylsulfoxy groups; arylsulfoxy groups; silyl groups; boron groups; alkyl groups; cycloalkyl groups; alkenyl groups; aryl groups; aralkyl groups; aralkylkenyl groups; alkylaryl groups; alkylamine groups; aralkylamine groups; heteroarylamine groups; arylamine groups; arylphosphine groups; or heterocyclic groups containing one or more N, O, and S atoms, or a substituent that is substituted or unsubstituted with two or more substituents linked together from the substituents exemplified above. For example, “substituents with two or more substituents linked together” may be biphenyl groups. That is, a biphenyl group may also be an aryl group and can be interpreted as a substituent with two phenyl groups linked together.

[0020] In this specification, the number of carbon atoms in the carbonyl group is not particularly limited, but it is preferably between 1 and 40 carbon atoms. Specifically, the compound may have, but is not limited to, the following structures. [ka]

[0021] In this specification, the ester group may be substituted with a linear, branched, or cyclic alkyl group having 1 to 25 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Specifically, the compounds may have, but are not limited to, the structural formulas shown below. [ka]

[0022] In this specification, the number of carbon atoms in the imide group is not particularly limited, but it is preferably 1 to 25. Specifically, it can be a compound having the following structure, but is not limited thereto. [Chemical formula]

[0023] In this specification, specific examples of the silyl group include, but are 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, and the like.

[0024] In this specification, specific examples of the boron group include, but are not limited to, a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, a phenylboron group, and the like.

[0025] In this specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

[0026] In this 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. In one embodiment, the alkyl group has 1 to 20 carbon atoms. In another embodiment, the alkyl group has 1 to 10 carbon atoms. In yet another embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of alkyl groups include, but are not limited to, 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, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, and 5-methylhexyl.

[0027] In this 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. In one embodiment, the number of carbon atoms in the alkenyl group is 2 to 20. In another embodiment, the number of carbon atoms in the alkenyl group is 2 to 10. In yet another embodiment, the number of carbon atoms in the alkenyl group is 2 to 6. Specific examples include 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 group, styrenyl group, etc., but are not limited to these.

[0028] In this specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms. In one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. In another embodiment, the cycloalkyl group has 3 to 20 carbon atoms. In yet another embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specifically, examples 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, and cyclooctyl.

[0029] In this 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. In one embodiment, the aryl group has 6 to 30 carbon atoms. In another embodiment, the aryl group has 6 to 20 carbon atoms. Examples of monocyclic aryl groups include, but are not limited to, phenyl groups, biphenyl groups, terphenyl groups, etc. Examples of polycyclic aryl groups include, but are not limited to, naphthyl groups, anthracenyl groups, phenanthryl groups, pyrenyl groups, perilenyl groups, chrysenyl groups, fluorenyl groups, etc.

[0030] In this specification, the fluorenyl group may be substituted, and two substituents may bond to each other to form a spiro structure. When the fluorenyl group is substituted, [ka] These are some possibilities, however, they are not limited to these.

[0031] In this specification, the heteroaryl group is a heterocyclic group having aromaticity and containing one or more heteroatoms from O, N, Si, and S, and the number of carbon atoms is not particularly limited, but is preferably 2 to 60. Examples of heteroaryl groups include, but are not limited to, thiophene, furan, pyrrole, imidazole, thiazole, oxazole, oxadiazole, triazole, pyridyl, bipyridyl, pyrimidine, triazine, acridyl, pyridazine, pyrazinyl, quinolinyl, quinazoline, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyradinyl, pyrazinopyradinyl, isoquinoline, indole, carbazole, benzoxazole, benzimidazole, benzothiazole, benzocarbazole, benzothiophene, dibenzothiophene, benzofuranyl, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, and dibenzofuranyl groups.

[0032] In this specification, the aryl group among the aralkyl group, aralkenyl group, alkylaryl group, and arylamine group is the same as the example of the aryl group described above. In this specification, the alkyl group among the aralkyl group, alkylaryl group, and alkylamine group is the same as the example of the alkyl group described above. In this specification, the heteroaryl among the heteroarylamine can be described using the description of the heterocyclic group described above. In this specification, the alkenyl group among the aralkenyl group is the same as the example of the alkenyl group described above. In this specification, the description of the aryl group described above can be described using the description of the aryl group described above, except that arylene is a divalent group. In this specification, the description of the heterocyclic group described above can be described using the description of the heterocyclic group described above, except that heteroarylene is a divalent group. In this specification, the description of the aryl group or cycloalkyl group described above can be described using the description of the aryl group or cycloalkyl group described above, except that the hydrocarbon ring is not a monovalent group but is formed by the bonding of two substituents. In this specification, the description of the heterocyclic group described above can be described using the description of the heterocyclic group described above, except that the heterocycle is not a monovalent group but is formed by the bonding of two substituents.

[0033] Furthermore, in this specification, polyfunctional compounds can be mixed with polyfunctional monomers or polyfunctional additives. The polyfunctional compounds, for example, refer to polyols having tetravalent or higher functional or reactive groups (e.g., -OH).

[0034] According to one embodiment of the present invention, a branched poly(3-hydroxypropionic acid) polymer represented by the following chemical formula 1 can be provided.

[0035] [Chemical formula 1] R-[A-(B)nC] k In the aforementioned chemical formula 1, R is a tetravalent or higher functional group derived from a polyfunctional monomer. A is either a direct bond or a linking group derived from an ether, sulfide, ester, thioester, ketone, sulfoxide, sulfone, sulfonate ester, amine, amide, imine, imide, or urethane.

[0036] B is a substituent represented by chemical formula 2 or chemical formula 3 below, [ka]

[0037] * is the part that is connected to A, k is an integer greater than or equal to 3, and n is an integer between 1 and 700. C is a substituent represented by chemical formula 4 or chemical formula 5 below. [ka]

[0038] In this context, a branched polymer is defined as a monomer polymer in which each functional group has three or more, or four or more, and the R portion in chemical formula 1 is defined as a branched structure.

[0039] For example, a branched structure is, [ka] This would mean structures such as those mentioned above, but it is not limited to these. In each branched unit, n can independently have any integer value from 1 to 700.

[0040] For example, k in chemical formula 1 may be an integer greater than or equal to 4, 5 to 6, 7 or greater, or 8 or greater. Although not particularly restricted, k in chemical formula 1 may be less than or equal to 20, less than or equal to 18, less than or equal to 16, less than or equal to 14, less than or equal to 12, less than or equal to 10, less than or equal to 8, or less than or equal to 6.

[0041] In one example, R may be a quadrivalent or higher linking group derived from a substituted or unsubstituted C1-60 alkyl, a substituted or unsubstituted C3-60 cycloalkyl, a substituted or unsubstituted C6-60 aryl, or a substituted or unsubstituted C2-60 heteroaryl containing one or more of N, O, and S. In this case, at least one of the carbon atoms of the alkyl, cycloalkyl, aryl, and heteroaryl may be substituted or unsubstituted with at least one heteroatom or carbonyl selected from the group consisting of N, O, and S.

[0042] Furthermore, the branched poly(3-hydroxypropionic acid) polymer satisfies an acid value of 150 meq / kg or less. Specifically, the acid value of the branched polymer may be, for example, 140 meq / kg or less, 135 meq / kg or less, 130 meq / kg or less, 125 meq / kg or less, 120 meq / kg or less, 115 meq / kg or less, 110 meq / kg or less, 105 meq / kg or less, 100 meq / kg or less, 95 meq / kg or less, 90 meq / kg or less, 85 meq / kg or less, 80 meq / kg or less, 75 meq / kg or less, 70 meq / kg or less, 65 meq / kg or less, 60 meq / kg or less, 55 meq / kg or less, 50 meq / kg or less, 45 meq / kg or less, 40 meq / kg or less, 35 meq / kg or less, or 30 meq / kg or less. Within the aforementioned acid value range, branched polymers can maintain a stable state and are advantageous for the formation of copolymers through reaction with other compounds. Therefore, the branched polymers of this application can enable an expansion of their industrial applications. The acid value can be measured by titrating with a 0.02N potassium methoxide solution as the titration solution, as shown in the experiment described later.

[0043] On the other hand, the inventors have also confirmed through experiments that when a polyhydric alcohol having four or more hydroxyl groups is used as a reaction additive to react with poly(3-hydroxypropionic acid), a monomer derived from bio, to form a novel branched poly(3-hydroxypropionic acid) polymer, polymers with diverse molecular weights, diverse thermal properties, and excellent acrylic structure can be produced through the formation of vinyl groups at the ends of each branched chain of the poly(3-hydroxypropionic acid) polymer.

[0044] In particular, by introducing a certain amount of vinyl groups at the chain ends in the novel branched structure, the molecular weight and particle structure of the acrylic polymer can be diversified. Thus, the branched poly(3-hydroxypropionic acid) polymer represented by chemical formula 1 of the novel structure may be an acrylic polymer having vinyl groups at the branched chain ends.

[0045] Furthermore, since the acrylic polymer is provided using a polyfunctional monomer with four or more valencies, it is possible that more chains will be formed and the number of vinyl groups at the branched ends will be greater than when a polyfunctional monomer with fewer than four valencies is used. As a result, the acrylic polymer can be made relatively less brittle or have its brittleness reduced compared to conventional acrylic polymers with similar molecular weights, and its Tg and Tm can also be reduced.

[0046] Specifically, acrylic polymers are derivatives of "CH2=CHCOOR" and have diverse applications such as fibers and adhesives.

[0047] Furthermore, existing conventional technologies, when providing biodegradable polymers such as poly(3-hydroxypropionic acid) polymers, either produce them by polymerizing P3HP (where the chain ends have hydroxyl groups) from poly(3-hydroxypropionic acid) to enable polymerization initiation with 3HP or other monomers, or they focus solely on the aspect of property changes. Therefore, the aforementioned poly(3-hydroxypropionic acid) polymers have limited structures and molecular weights, and are limited in their ability to realize diverse properties (e.g., thermal properties).

[0048] This allows for the production of acrylic polymers with diverse molecular weights, from low to high, by introducing poly(3-hydroxypropionic acid), an environmentally friendly monomer derived from bio, in order to improve the usability of the acrylic polymer and impart diverse physical properties to the poly(3-hydroxypropionic acid) polymer. Furthermore, by using polyhydric alcohols of tetravalent or higher as polyfunctional monomers for vinylization treatment of the polymer chain ends for acrylic structure formation.

[0049] Furthermore, the acrylic polymer produced may be a branched poly(3-hydroxypropionic acid) polymer having four or more branched structures from a linear structure, by using a polyhydric alcohol of tetravalent or higher as a polyfunctional monomer. In other words, introducing a polyhydric alcohol of tetravalent or higher as the polyfunctional monomer makes the vinylization treatment of the chain ends of the branched poly(3-hydroxypropionic acid) polymer easier. Therefore, since the polymer can be easily produced in a variety of structures from linear to hyperbranched, the application fields of acrylic polymers can be expanded.

[0050] Furthermore, by further vinylization treatment of the hydroxyl groups at the ends of the polymer chains of the branched poly(3-hydroxypropionic acid) polymer through the addition of an acid catalyst and heat treatment conditions, the formation of vinyl groups at the ends of each branched chain can be adjusted to produce acrylic polymer compounds with diverse content.

[0051] Furthermore, the branched poly(3-hydroxypropionic acid) polymer is an environmentally friendly, biodegradable polymer that can have different thermal properties (Tg, Tm) depending on its diverse polymer structure.

[0052] Therefore, the branched poly(3-hydroxypropionic acid) polymers having the diverse acrylic polymer structures can be used in a variety of ways, such as radical polymerization monomers and elastomers.

[0053] With this configuration, this specification can provide an acrylic polymer in which a polyhydric alcohol of tetravalent or higher is used and the molecular weight and particle structure of the branched poly(3-hydroxypropionic acid) polymer are diversified.

[0054] Furthermore, the weight-average molecular weight of the branched poly(3-hydroxypropionic acid) polymer can be adjusted. For example, it can be made to have a weight-average molecular weight of 1,000 to 100,000 or higher.

[0055] Furthermore, the branched poly(3-hydroxypropionic acid) polymer includes an acrylic polymer having one or more, preferably three to four or more polymer molecular chains, with a portion of the terminal ends of the branched chains consisting of vinyl groups.

[0056] Specifically, in the branched poly(3-hydroxypropionic acid) polymer, the ratio of the number of chemical formulas 5 to the total of chemical formulas 4 and 5, that is, the branched-end vinyl group content, may be 5% or more, 10% or more, 20% or more, 30% or more, 40% by weight or more, 42% by weight or more, 45% by weight or more, 50% by weight or more, 52% by weight or more, 55% by weight or more, 100% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 75% by weight or less, 72% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, or 56% by weight or less.

[0057] Furthermore, the number ratio of chemical formula 5 to the total of chemical formulas 4 and 5 (branched-end vinyl group content) may be the content in unpurified or purified branched poly(3-hydroxypropionic acid) polymers.

[0058] When the branched poly(3-hydroxypropionic acid) polymer is purified, the branched-terminal vinyl group content of the polymer produced under the same conditions can be further increased. According to a preferred embodiment of the invention, in the case of a purified branched poly(3-hydroxypropionic acid) polymer produced under the same conditions, the number ratio of chemical formula 5 to the sum of chemical formulas 4 and 5 may be 55% by weight or more and 100% by weight or less.

[0059] In this case, if the vinyl group content of chemical formula 5 at the branched ends of the polymer is less than 5%, the non-acrylic chain ends may exhibit properties similar to those of a poly(3-hydroxypropionic acid) polymer that can initiate polymerization with 3HP or other monomers, making it difficult to achieve the desired effect.

[0060] On the other hand, the ratio of the number of chemical formulas 5 to the total of chemical formulas 4 and 5 (branched-terminal vinyl group content) can be determined by measuring the vinyl group structure at the end of the polymer chain using 1H-NMR.

[0061] Specifically, the vinyl group content at the branched end is determined by the CH peak value of the vinyl group of chemical formula 5 at the branched end of each polymer using 1H-NMR. <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> ) can be measured and calculated using the following formula 1. [ka]

[0062] In the above equation 1, <1> This is the CH peak value of the vinyl group of chemical formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer. <2> This is the terminal beta CH peak value of chemical formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0063] In this case, in chemical formula 4 or 5, * may be the part that is connected to B.

[0064] The polymer is obtained by condensation polymerization of 3-hydroxypropionic acid with a polyfunctional monomer, wherein the polyfunctional monomer is a polyhydric alcohol having 4 or more hydroxyl groups.

[0065] As mentioned above, the branched polymer may be formed by the condensation polymerization of 3-hydroxypropionic acid with a polyfunctional compound. The types of polyfunctional compounds used in the production of branched polymers are not particularly limited, but for example, the polyfunctional compounds include pentaerythritol, 4-arm-poly(ethyleneglycol)n=2~10, di(trimethylolpropane), di(pentaerythritol), tripentaerythritol, xylitol, sorbitol, inositol, cholic acid, β-cyclodextrin, tetrahydroxyperylene, pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid, and tetraacetylene It may also include one or more selected from the group consisting of pentamines. [ka]

[0066] As described above, the branched polymer contains 3-hydroxypropionic acid; and units derived from 0.05 to 50 parts by weight of a polyfunctional compound per 100 parts by weight of 3-hydroxypropionic acid. For example, the polymer may contain 0.1 parts by weight or more, 1 part by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, or 45 parts by weight or more of the polyfunctional compound (per 100 parts by weight of 3-hydroxypropionic acid). Alternatively, the branched polymer may contain 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, 1 part by weight or less, or 0.5 parts by weight or less of the polyfunctional compound (per 100 parts by weight of 3-hydroxypropionic acid). Within the aforementioned content range, branched polymers that can achieve the target objective can be produced. As confirmed in the experiments described later, branched polymers with high molecular weights can be obtained even with a low content of polyfunctional compounds.

[0067] As one example, the branched polymer may be obtained by condensation polymerization of a polyfunctional compound in an amount of 0.005 mol% or more relative to the content of 3-hydroxypropionic acid. In producing the branched polymer of this application, the aforementioned polyfunctional compound plays a role similar to an initiator, and therefore can adequately perform its function even in small amounts.

[0068] Specifically, polyfunctional compounds can be used to polymerize branched polymers in amounts of 0.01 mol% or more, 0.1 mol% or more, 0.5 mol% or more, 1 mol% or more, 5 mol% or more, or 10 mol% or more relative to the content of 3-hydroxypropionic acid. There are no particular restrictions, but the upper limit may be, for example, 25 mol% or less, 20 mol% or less, specifically 15 mol% or less, 14.5 mol% or less, 14.0 mol% or less, 13.5 mol% or less, 13.0 mol% or less, 12.5 mol% or less, 12.0 mol% or less, 11.5 mol% or less, 11.0 mol% or less, 10.5 mol% or less, 10 mol% or less, 9.5 mol% or less, 9 mol% or less, 8.5 mol% or less, 8 mol% or less, 7.5 mol% or less, 7 mol% or less, 6.5 mol% or less, 6 mol% or less, 5.5 mol% or less, or 5.0 mol% or less. Within the aforementioned content range, branched polymers that can achieve the target objective can be produced.

[0069] As one example, the branched polymer may have a weight-average molecular weight (Mw) in the range of 1,000 to 300,000. Specifically, the weight-average molecular weight (Mw) of the polymer may be, for example, 2,000 or more, 3,000 or more, 4,000 or more, 5,000 or more, 6,000 or more, 7,000 or more, 8,000 or more, 9,000 or more, 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, 50,000 or more, 55,000 or more, 60,000 or more, 65,000 or more, 70,000 or more, 75,000 or more, 80,000 or more, 85,000 or more, 90,000 or more, or 100,000 or more. Furthermore, the upper limit may be, for example, 250,000 or less, 200,000 or less, 150,000 or less, 100,000 or less, 50,000 or less, 45,000 or less, 40,000 or less, 35,000 or less, 30,000 or less, 25,000 or less, 20,000 or less, 15,000 or less, or 10,000 or less. Thus, according to the specific example of this application, when producing branched polymers, the content of the reactive components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) and / or the reaction conditions can be controlled to make branched polymers have molecular weight characteristics of various grades.

[0070] As one example, the branched polymer may have a number-average molecular weight (Mn) in the range of 500 to 100,000. Specifically, the number-average molecular weight (Mn) of the polymer may be, for example, 1,000 or more, 2,000 or more, 3,000 or more, 4,000 or more, 5,000 or more, 6,000 or more, 7,000 or more, 8,000 or more, 9,000 or more, 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, 50,000 or more, 55,000 or more, 60,000 or more, 65,000 or more, 70,000 or more, 80,000 or more, 85,000 or more, 90,000 or more, or 95,000 or more. Furthermore, the upper limit may be, for example, 95,000 or less, 90,000 or less, 85,000 or less, 80,000 or less, 75,000 or less, 70,000 or less, 65,000 or less, 60,000 or less, 55,000 or less, 50,000 or less, 45,000 or less, 40,000 or less, 35,000 or less, 30,000 or less, 25,000 or less, 20,000 or less, 15,000 or less, or 10,000 or less. Thus, according to the specific example of this application, when producing branched polymers, the content of the reaction components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) and / or the reaction conditions can be controlled to make branched polymers have molecular weight characteristics of various grades.

[0071] For example, the branched polymer may have a polydispersity index (PDI) in the range of 1.0 to 13.0. Specifically, the polydispersity index (PDI) of the polymer may be, for example, 1.5 or more, 2.0 or more, 2.5 or more, 3.0 or more, 3.5 or more, 4.0 or more, 4.5 or more, or 5.0 or more, and its upper limit may be, for example, 12.0 or less, 11.5 or less, 11.0 or less, 10.5 or less, 10.0 or less, 9.5 or less, 9.0 or less, 8.5 or less, 8.0 or less, 7.5 or less, 6.5 or less, 6.0 or less, 5.5 or less, or 5.0 or less. Thus, according to the specific example of this application, when producing the branched polymer, the content of the reactive components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) and / or the reaction conditions can be controlled to make the branched polymer have molecular weights of various grades.

[0072] The methods for measuring the weight-average molecular weight, number-average molecular weight, and polydispersity index will be explained in relation to the experiments described later.

[0073] According to another embodiment of the present invention, a method for producing the branched poly(3-hydroxypropionic acid) polymer can be provided.

[0074] Specifically, the method includes the step of polymerizing 3-hydroxypropionic acid with a polyfunctional compound with a tetravalent or higher valency to produce a branched poly(3-hydroxypropionic acid) polymer represented by the following chemical formula 1.

[0075] The aforementioned branched poly(3-hydroxypropionic acid) polymer can satisfy the requirement of having an acid value of 150 meq / kg or less.

[0076] The structure of the polymer provided by the method of the above embodiment, as shown in chemical formula 1, is identical to that of the branched poly(3-hydroxypropionic acid) polymer described above. The specific types, content, and properties of the monomers or compounds forming the polymer are also the same as described above, so a detailed explanation is omitted.

[0077] In one example, the polymerization may be carried out in the presence of a catalyst. The use of a catalyst is advantageous in promoting the polymerization reaction and suppressing the formation of cyclic oligomers during the polymerization process. The type of catalyst is not particularly limited, as long as it does not hinder the progress of the polymerization reaction or the achievement of the object of this application. Usable catalysts may be, for example, acid catalysts or tin-based catalysts. Acid catalysts may be, for example, sulfonic acid-based catalysts or contain such catalysts, and examples of sulfonic acid-based catalysts include p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid and / or p-xylene-2-sulfonic acid. As for tin-based catalysts, for example, SnCl2 or Sn(oct)2 may be used.

[0078] The catalyst can be used within a predetermined content range. For example, polymerization may be carried out using the catalyst in an amount of 0.001 to 1.0 mol% relative to the 3-hydroxypropionic acid. Specifically, the content of the catalyst may be 0.01 mol% or more, 0.05 mol% or more, or 0.1 mol% or more, and its upper limit may be, for example, 0.9 mol% or less, 0.8 mol% or less, 0.7 mol% or less, 0.6 mol% or less, or 0.5 mol% or less. Using the catalyst within the aforementioned content range may be advantageous in that it promotes polymerization while suppressing the formation of cyclic oligomers.

[0079] As one example, the polymerization may be carried out under vacuum conditions. In this case, a vacuum condition means a pressure lower than atmospheric pressure, for example, a pressure of 500 torr or less. Although not particularly limited, the polymerization may be carried out at pressures of 100 torr or less, 50 torr or less, 10 torr or less, 1 torr or less, or 0.1 torr or less.

[0080] For example, the polymerization may be carried out in a temperature range of 50 to 150°C. Specifically, the polymerization may be carried out at temperatures of 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°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 this case, the polymerization reaction temperature may be selected within a temperature range in which side reactions are suppressed and a sufficient yield is ensured.

[0081] For example, the polymerization may be carried out for 1 to 70 hours. Specifically, the polymerization carried out under the vacuum conditions and temperature range described above may be carried out for 2 hours or more, 3 hours or more, 4 hours or more, or 5 hours or more, and may be carried out for 60 hours or less, 55 hours or less, 50 hours or less, 45 hours or less, 40 hours or less, 35 hours or less, 30 hours or less, 25 hours or less, 20 hours or less, 15 hours or less, 10 hours or less, or 5 hours or less. In this case, the polymerization may be carried out for a period of time during which side reactions are suppressed and a sufficient yield is ensured.

[0082] In one example, the method may further include a catalyst removal or crystallization step performed after the polymerization reaction described above. For example, the step may involve mixing the organic solvent with the branched polymer and performing the step under temperature conditions of 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less, and 30°C or more, or 40°C or more. This removes the catalyst while the branched polymer crystallizes. The type of organic solvent used is not particularly limited, and publicly disclosed ones may be used.

[0083] As one example, the method may further include an oligomerization reaction step performed before the polymerization reaction described above. Specifically, the method may further include an oligomerization step performed at 50 to 100°C and under vacuum (e.g., 100 torr or less, 50 torr or less, 10 torr or less). If an oligomerization step is performed, the occurrence of side reactions can be suppressed. The time for which such an oligomerization reaction is performed is not particularly limited, but may be, for example, 300 minutes or less, 250 minutes or less, 200 minutes or less, 150 minutes or less, or 100 minutes or less, and may be 30 minutes or more or 60 minutes or more.

[0084] In one example, the method may further include a step of drying one or more of the 3-hydroxypropionic acid and the polyfunctional compound before the polymerization or oligomerization reaction step. Such drying is intended to accommodate the case where the reactants (3-hydroxypropionic acid and / or polyfunctional compound) are mixed in aqueous solution. The drying conditions are not particularly limited, but may be, for example, 30 to 100°C and under vacuum (about 50 to 300 torr) for a predetermined time, for example, 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, or 1 hour or less.

[0085] On the other hand, according to yet another embodiment of the present invention, a method for producing a branched poly(3-hydroxypropionic acid) polymer represented by the following chemical formula 1 can be provided, comprising the steps of: polymerizing 3-hydroxypropionic acid with a polyfunctional monomer having 4-valent or higher hydroxyl groups to produce an acrylic primary polymer; and heat-treating the acrylic primary polymer to produce an acrylic secondary polymer.

[0086] The step of producing the aforementioned acrylic primary polymer is to produce poly(3-hydroxypropionic acid) (P3HP) through the primary condensation polymerization of 3-hydroxypropionic acid into a polyfunctional monomer having 4 or more hydroxyl groups.

[0087] The polyfunctional monomer may be used in an amount of 0.1 mol% to 25 mol% relative to the 3-hydroxypropionic acid content. When the polyfunctional monomer content is 25 mol%, the number of hydroxyl groups in the tetravalent polyhydric alcohol may be the same as the number of 3-hydroxypropionic acid, which is the starting material.

[0088] Therefore, when polymerized within the aforementioned content range, it is suitable for forming the desired branched acrylic primary polymer structure as an appropriate crosslinked structure in excellent yield. If the content of the polyfunctional monomer is less than 0.1 mol%, the amount of poly(3-hydroxypropionic acid), which is a linear structure formed by condensation polymerization of 3-hydroxypropionic acid alone, rather than a branched structure formed by the reaction of the polyfunctional monomer with 3-hydroxypropionic acid, increases, which may not be in line with the objectives of the present invention.

[0089] Furthermore, if the content of the polyfunctional monomer exceeds 25 mol%, the addition of an excess amount can lead to side reactions, making it difficult to obtain acrylic polymers with diverse molecular weights, and resulting in longer reaction times and reduced process efficiency.

[0090] Preferably, the polyfunctional monomer content may be 0.1 mol% to 20 mol%, 0.1 mol% to 15 mol%, 0.1 mol% to 10 mol%, 0.1 mol% to 5 mol%, 0.1 mol% to 1 mol% or less, or 0.1 mol% to 0.5 mol% or less, or 0.1 mol% or more, 0.5 mol% or more, or 1.0 mol% or more, or 20 mol% or less, 15 mol% or less, 10 mol% or less, 5 mol% or less, 1 mol% or less, or 0.5 mol% or less, relative to the 3-hydroxypropionic acid content. In this case, polymers can be formed without the aforementioned problems.

[0091] The polymerization may be carried out at 50°C to 100°C and 5 torr or less under acid catalyst for 10 hours or more.

[0092] Preferably, the polymerization is carried out by a condensation reaction at 50°C to 100°C and 0.1 torr to 5 torr or less under acid catalyst for 10 to 50 hours to produce an acrylic primary polymer. The polymerization reaction time may be 10 hours or more, 15 hours or more, 20 hours or more, 25 hours or more, 50 hours or less, 45 hours or less, 40 hours or less, or 35 hours or less.

[0093] When melt polymerization is carried out under the above conditions, the generation of side reaction products can be suppressed during the production of acrylic primary polymers.

[0094] For your reference, the reaction after oligomerization can be appropriately adjusted according to the content range of the polyfunctional monomer used. If an excess amount of polyfunctional monomer is used, the reaction time will be prolonged, and side reactions such as chain transfer and gelation may occur. In such cases, the reaction may be appropriately adjusted to be carried out within about 24 hours.

[0095] Furthermore, the acid catalyst may also be a sulfonic acid-based catalyst. The catalyst has the effect of promoting the polymerization of 3-hydroxypropionic acid and suppressing the formation of cyclic oligomers during the polymerization process.

[0096] According to one embodiment of the present invention, the sulfonic acid catalyst may be p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, or p-xylene-2-sulfonic acid.

[0097] Preferably, the acid catalyst is used in an amount of 0.01 mol% to 1 mol% relative to the 3-hydroxypropionic acid content, and may be added appropriately in an equivalent amount of 0.1 to 0.3 mol%.

[0098] If the acid catalyst content is excessively small, less than 0.01 mol%, the reaction progress will be slow, and if the acid catalyst content exceeds 1 mol%, an over-addition may occur, leading to side reactions. The amount of catalyst added may vary depending on the type of catalyst, and the acid catalyst content may be based on sulfonic acid-based catalysts.

[0099] Therefore, by using an acid catalyst within the above range, polymerization can be promoted to produce acrylic polymers containing vinyl groups at the branched chain ends, which have diverse molecular weights and thermal properties. Preferably, the content of the sulfonic acid catalyst may be 0.01 mol% to 0.8 mol%, 0.02 mol% to 0.5 mol%, or 0.1 mol% to 0.3 mol%, or 0.01 mol% or more, or 0.02 mol% or more, or 0.1 mol% or more, 0.8 mol% or less, 0.5 mol% or less, or 0.3 mol% or less.

[0100] The heat treatment is a step in which the acrylic primary polymer is subjected to an additional secondary polymerization reaction under high temperature conditions to form additional vinyl groups at the chain ends of the acrylic primary polymer, thereby producing acrylic secondary polymers having diverse structures and molecular weights. Through this step, a branched poly(3-hydroxypropionic acid) polymer represented by the chemical formula 1 can be provided.

[0101] Preferably, the heat treatment may be carried out at 100°C to 200°C for 1 to 20 hours with or without stirring. The heat treatment time may be 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, 20 hours or less, 15 hours or less, 10 hours or less, or 5 hours or less.

[0102] If the heat treatment temperature is less than 100°C, condensation polymerization with 3-hydroxypropionic acid used as a raw material becomes dominant over the formation of vinyl groups at the chain ends of the acrylic primary polymer, and an acrylic structure is not formed. Furthermore, if the heat treatment temperature exceeds 200°C, there is a problem that the decomposition of 3-hydroxypropionic acid occurs due to the excessively high temperature, increasing the number of side reactions. In addition, if the heat treatment time is less than 1 hour, there is a problem that it is difficult to measure the formation of vinyl groups at the chain ends of the primary polymer, and if the heat treatment time is 20 hours or more, there is a problem that the reaction for forming vinyl groups at the chain ends of the polymer becomes saturated and ineffective.

[0103] Furthermore, the heat treatment may be carried out under an inert atmosphere at a pressure of 0.1 to 760 torr or atmospheric pressure. Nitrogen, argon, and the like may be used for the composition of the inert atmosphere.

[0104] Furthermore, the heat treatment may be carried out in the presence of an acid catalyst. The catalyst is used under the same conditions as in the production step of the acrylic primary polymer, and the additional polymerization of the acrylic primary polymer can be promoted to produce an acrylic secondary polymer with a desired molecular weight and structure.

[0105] Alternatively, the process may further include a step of dissolving the heat-treated acrylic secondary polymer in an organic solvent and then purifying it by adding a non-solvent.

[0106] Through the aforementioned purification process, polymer impurities can be removed, thereby improving purity.

[0107] The organic solvent can be used in an amount of 500 to 2,000 parts by weight based on 100 parts by weight of the heat-treated acrylic secondary polymer. If the content of the organic solvent is less than 500 parts by weight, there is a problem that the weight of the acrylic secondary polymer may exceed the solubility of the solvent, and the polymer may not dissolve. If it exceeds 2,000 parts by weight, there is a problem that the crystallinity may decrease when a non-solvent is added.

[0108] The aforementioned organic solvent may be a hydrocarbon-based organic solvent such as chloroform, ethyl ether, n-hexane, or toluene.

[0109] The non-solvent may be added in an amount of 10 to 500 parts by weight based on 100 parts by weight of the organic solvent. If the non-solvent content is less than 10 parts by weight, there is a problem that the crystallinity of the polymer to be purified will be low, and if it exceeds 500 parts by weight, there is a problem that the purity of the polymer may be low.

[0110] The aforementioned non-solvent may be ethanol, water, methanol, isopropanol, or the like.

[0111] The purification step may be carried out under temperature conditions of -10°C to 100°C. If the purification temperature is below -10°C, there is a problem that the solubility of the solvent for the polymer will be low and it may not dissolve, and if it exceeds 100°C, there is a problem that it may be higher than the boiling points of the solvent and non-solvent.

[0112] Furthermore, in the purification step described above, the precipitated acrylic secondary polymer can be filtered and then dried at room temperature and under vacuum conditions to provide purified branched poly(3-hydroxypropionic acid) polymer in particle form.

[0113] The aforementioned filter and drying method may be any method well known in the art, without limitation.

[0114] Furthermore, if necessary, the process may further include a step in which the 3-hydroxypropionic acid and the polyfunctional monomer are each independently pretreated at 50°C to 100°C and 100 torr or less before polymerization. Through this pretreatment step, water present in the 3-hydroxypropionic acid and the polyfunctional monomer can be removed.

[0115] Preferably, the 3-hydroxypropionic acid may further include a step of pre-treatment at 50°C to 100°C, 100 torr or less, or 60°C to 100 torr for 1 to 2 hours before polymerization.

[0116] According to yet another embodiment of the present invention, an article comprising the branched poly(3-hydroxypropionic acid) polymer can be provided.

[0117] For example, the branched polymer may be used alone or in combination with other polymer components to form all or part of a particular article for a specific purpose. Such articles include, for example, packaging materials, films, nonwoven fabrics and / or injection-molded products.

[0118] As stated above, this application can provide a high molecular weight branched polymer, which can be used to form the aforementioned articles on its own. Furthermore, this application can provide polymers with molecular weights of various grades, thereby broadening the range of industrial applications for articles containing the branched polymer. [Effects of the Invention]

[0119] This specification provides branched poly(3-hydroxypropionic acid) polymers that are biodegradable, have a high molecular weight, and are advantageous for industrial applications. [Modes for carrying out the invention]

[0120] The embodiments of the present invention will be described in more detail below with reference to 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 to the following examples. [Examples]

[0121] <Examples 1 to 5: Production of branched copolymers> Example 1 3-hydroxypropionic acid (3HP) and pentaerythritol dissolved in water were placed in RBF and dried at 90°C and 100 torr for 2 hours.

[0122] 70 g of dried 3-hydroxypropionic acid (3HP) and 0.154 g of pentaerythritol were placed in a reactor, and a condensation polymerization reaction was carried out at 90°C under a vacuum of 1 torr for 30 hours using 295.6 mg of p-TSA (0.2 mol%) relative to 3HP as a catalyst to produce a branched copolymer.

[0123] Example 2 A branched copolymer was produced in the same manner as in Example 1, except that dipentaerythritol was used instead of pentaerythritol.

[0124] Example 3 A branched copolymer was produced in the same manner as in Example 1, except that di(trimethylolpropane) was used instead of pentaerythritol.

[0125] Example 4 A branched copolymer was produced in the same manner as in Example 1, except that tripentaerythritol was used instead of pentaerythritol.

[0126] Example 5 Branched polymers were produced in the same manner as in Example 1, except that sorbitol was used instead of pentaerythritol.

[0127] <Comparative Examples 1 to 3> Comparative Example 1 3-hydroxypropionic acid (3HP) dissolved in water was placed in RBF and dried at 90°C and 100 torr for 2 hours.

[0128] 60 g of dried 3-hydroxypropionic acid (3HP) was placed in a reactor, and a condensation polymerization reaction was carried out at 80°C under a vacuum of 1 torr for 20 hours using 295.6 mg of p-TSA as a catalyst to produce a linear polymer.

[0129] Comparative Example 2 In Comparative Example 1, the copolymer was produced by the same method, except that polymerization including the oligomerization reaction was carried out for 25 hours.

[0130] Comparative Example 3 Pentaerythritol (7.7g), SnO (tin oxide(II), 1.0g), and lactic acid (300g) were placed in RBF and reacted at 150°C and 30mbar for 15 hours to polymerize the copolymer.

[0131] NMR analysis of the obtained copolymer confirmed that it substantially did not contain terminal vinyl groups, as no peaks were detected between 5.5 and 7.0 ppm.

[0132] <Experimental Example 1> The properties of the branched polymers produced in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated as follows.

[0133] (1) Evaluation of molecular weight using GPC (gel permeation chromatography) The molecular weight of the copolymers produced in each step of the above examples and comparative examples was evaluated using a Water e2695 model and Agilent Plgel mixed c and b columns. A sample was prepared at 4 mg / ml, and 20 μl was injected into chloroform as the solvent. The weight-average molecular weight, number-average molecular weight, and polydispersity index were measured using gel permeation chromatography (GPC, Tosoh ECO SEC Elite), and the results are shown in Table 1 below. Solvent: Chloroform (eluent) Flow rate: 1.0ml / min Column temperature: 40℃ Standard: Polystyrene (corrected with a cubic function)

[0134] (2) Vinyl group content at branch terminals Using 1H-NMR, the CH peak values ​​of the vinyl group of chemical formula 5 at the branched ends of each polymer were determined. <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> The following values ​​were measured and calculated using Equation 1 below. [ka]

[0135] In the above equation 1, <1> This is the CH peak value of the vinyl group of chemical formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer. <2> This is the terminal beta CH peak value of chemical formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0136] (3) Acid value measurement (unit: meq / kg) The titration point of the polymer was analyzed by titrating with a 0.02N potassium methoxide solution. A DGi 116-solvent electrode was used with a Mettler Toledo T5 setup. [Table 1]

[0137] As can be seen in Table 1 above, Examples 1 to 5 contain vinyl groups at 5% or more of the branched ends, demonstrating diversity in polymer structure. This allows for the production of branched poly(3-hydroxypropionic acid) polymers with acrylic structures that have a wide range of molecular weights and other thermal properties while maintaining their intrinsic physical properties.

[0138] According to the above-described examples, during heat treatment, the formation of branched vinyl groups at the end of the branches and crosslinking between the branches diversify the polymer structure having four or more branched structures as desired. If multiple end groups are present, ductility can be imparted to the polymer material, and the Tm is reduced. This has the effect of inactivating the -OH functional groups contained in the polymer, minimizing the problem of impurities remaining in the oligomer during polymer copolymerization, such as PLH.

[0139] In contrast, the copolymers obtained in Comparative Examples 1 and 2 were found to have a relatively high acid value and relatively low weight-average molecular weight and PDI value.

[0140] Furthermore, NMR data confirmed that the copolymer obtained in Comparative Example 3, which was obtained by reacting pentaerythritol with lactic acid, did not have vinyl groups formed at its ends.

[0141] <Examples 6 to 12: Production of branched-chain copolymers> Example 6 A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round-bottom flask (RBF) and pretreated at 80°C and below 100 torr for 2 hours.

[0142] 100 g of pre-treated 3-hydroxypropionic acid (3HP) and 0.2 g of pentaerythritol as a polyhydric alcohol were placed in a reactor, and 300 mg of p-TSA (0.1 mol% relative to 3HP) was used as an acid catalyst. Primary polymer polymerization was carried out at 80°C for more than 20 hours to produce an acrylic primary polymer. The pressure inside the reactor was maintained at less than 5 torr during polymerization.

[0143] The acrylic primary polymer (P3HP) produced was melted at 100°C, then heated to 150°C, and the heat treatment was maintained for 2 hours under an acid catalyst of 300 mg of p-TSA (0.1 mol per 3 HP). After this, the secondary polymer polymerization reaction was terminated to produce a branched polymer of chemical formula 1 having vinyl groups at the chain ends (crude). The heat treatment was performed for less than 5 torr.

[0144] Example 7 A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round-bottom flask (RBF) and pretreated at a temperature of 90°C or below and a temperature of 100 torr or below for 2 hours.

[0145] 50 g of pre-treated 3-hydroxypropionic acid (3HP) and 0.1 g of pentaerythritol as a polyhydric alcohol were placed in a reactor, and primary polymer polymerization was carried out at 85°C for more than 15 hours using 300 mg of p-TSA (0.3 mol%) relative to 3HP as an acid catalyst. The pressure inside the reactor was maintained at less than 10 torr during polymerization.

[0146] The acrylic primary polymer (P3HP) produced was melted at 100°C, then heated to 170°C, and the heat treatment was maintained for more than 10 hours under an acid catalyst with 200 mg of p-TSA (0.18 mol per 3HP). After this, the secondary polymer polymerization reaction was terminated to produce a branched polymer of chemical formula 1 having vinyl groups at the chain ends. The heat treatment was carried out under atmospheric pressure (crude).

[0147] Example 8 A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round-bottom flask (RBF) and concentrated by drying the water at 65°C and 70 torr for 2 hours.

[0148] 100 g of pre-treated 3-hydroxypropionic acid (3HP) and 0.3 g of pentaerythritol as a polyhydric alcohol were placed in a reactor, and primary polymer polymerization was carried out at 95°C and under a pressure of less than 1 torr (0.6 torr) for 16 hours using 400 mg of p-TSA (0.18 mol%) relative to 3HP as an acid catalyst.

[0149] The acrylic primary polymer (P3HP) produced was melted at 100°C, then heated to 140°C, and subjected to a secondary polymerization reaction for 5 hours under a pressure of 0.6 torr and with 400 mg of p-TSA (0.18 mol per 3HP) as an acid catalyst, without stirring, to produce a branched polymer of chemical formula 1 having vinyl groups at the chain ends (crude).

[0150] Example 9 A small amount (2 to 3 g) of the primary polymer (P3HP) polymerized in Example 8 was placed in a vial reactor, melted at 90°C, then heated to 150°C, and subjected to a secondary polymerization reaction without stirring under a pressure of 0.9 torr and an acid catalyst of 80 mg of p-TSA (0.18 mol per 3 HP) for more than 15 hours to produce a branched polymer having vinyl groups at the chain ends (crude).

[0151] Example 10 A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round-bottom flask (RBF) and concentrated at 80°C and 60 torr for 2 hours.

[0152] 55 g of concentrated 3-hydroxypropionic acid (3HP) and 0.2 g of pentaerythritol as a polyhydric alcohol were placed in a reactor, and 210 mg of p-TSA (0.18 mol%) (relative to 3HP) was used as an acid catalyst. The mixture was concentrated at 80°C under a pressure of 60 torr. Subsequently, primary polymer polymerization was carried out at the same temperature (80°C) and under a high vacuum pressure of 1-2 torr for 21 hours.

[0153] The aforementioned acrylic primary polymer (P3HP) was heated to 180°C under atmospheric pressure and nitrogen, followed by a heat treatment reaction with 210 mg of p-TSA (0.18 mol / 3HP) under an acid catalyst for 1 hour. After this, the secondary polymerization reaction was terminated to produce a branched polymer of chemical formula 1 having vinyl groups at the chain ends (crude).

[0154] Example 11 In Example 10, a branched polymer having vinyl groups at the chain ends was produced in the same manner as in Example 10, except that the primary polymer polymerization time was changed to 25 hours (crude).

[0155] Example 12 30 g of the branched polymer from Example 10 was dissolved in 300 mL of chloroform, and then 500 mL of ethanol was added at a slow rate to precipitate the polymer.

[0156] The precipitated polymer was filtered and dried overnight in a vacuum oven (10 torr) at room temperature to produce a purified branched polymer with vinyl groups at the chain ends.

[0157] <Experimental Example 2> The properties of the polymers produced in Examples 6 to 12 were evaluated as follows. (1) Evaluation of molecular weight using GPC (gel permeation chromatography) For each step of the polymer produced in the above examples and comparative examples, the molecular weight was evaluated using a Water e2695 model and Agilent Plgel mixed c and b columns. A sample was prepared at 4 mg / ml, and 20 μl was injected into chloroform as the solvent. The weight-average molecular weight (Mw), number-average molecular weight (Mn), molecular weight of the maximum peak (Mn), and polydispersity index (PDI) were measured using gel permeation chromatography (GPC, Tosoh ECO SEC Elite), and the results are shown in Table 1 below. Solvent: Chloroform (eluent) Flow rate: 1.0ml / min Column temperature: 40℃ Standard: Polystyrene (corrected with a cubic function)

[0158] (2) Vinyl group content at branch terminals Using 1H-NMR, the CH peak values ​​of the vinyl group of chemical formula 5 at the branched ends of each polymer were determined. <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> The following values ​​were measured and calculated using Equation 1 below. [ka]

[0159] In the above equation 1, <1> This is the CH peak value of the vinyl group of chemical formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer. <2> This is the terminal beta CH peak value of chemical formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0160] (3) Evaluation of thermal properties using DSC (differential scanning calorimetry) For each step of the copolymer produced in the above examples and comparative examples, the thermal properties (Tg, Tm, Tcc (cold crystallization, 2nd heating result), Tc (1st cooling result)) were measured under nitrogen gas flow conditions using a TA DSC250 model, and the results are shown in Table 2 below.

[0161] Thermal scanning was performed by heating and cooling each copolymer at a rate of 10°C / min within a temperature range of -80°C to 150°C.

[0162] Furthermore, the temperature was cooled from 150°C to -80°C at a rate of 10°C / min (1st cooling), maintained at -80°C for 10 minutes, and then heated from -80°C to 150°C at a rate of 10°C / min (2nd heating). [Table 2]

[0163] As can be seen in Table 2 above, Examples 6 to 12 contain vinyl groups at 5% or more of the branched ends, exhibiting diversity in polymer structure. This allows for the production of branched poly(3-hydroxypropionic acid) polymers with acrylic structures that have a wide range of molecular weights and other thermal properties while maintaining their intrinsic physical properties.

[0164] According to the above examples, during heat treatment, the polymer structure having four or more branched structures is diversified through the formation of branched terminal vinyl groups and crosslinking between branches, and it can be confirmed that the resulting thermal properties result in lower Tg and Tm compared to the comparative example.

[0165] Furthermore, generally, a faster crystallization rate results in a larger enthalpy Tc and less or no cold crystallization, while a higher degree of crystallinity may increase the enthalpy Tm. Also, while a higher degree of crystallinity results in higher material strength, it is brittle and lacks elasticity.

[0166] However, in the examples, the content of branched-terminal vinyl groups can be varied to lower Tm and reduce the degree of crystallinity of the branched structure, thereby reducing brittle properties.

Claims

1. A branched poly(3-hydroxypropionic acid) polymer represented by the following chemical formula 1, containing vinyl groups at its terminals. [Chemical formula 1] R-[A-(B)n-C] ｋ In the aforementioned chemical formula 1, R is a tetravalent or higher functional group derived from a polyfunctional monomer. A is either a direct bond or a linking group derived from an ether, sulfide, ester, thioester, ketone, sulfoxide, sulfone, sulfonate ester, amine, amide, imine, imide, or urethane. B is a substituent represented by chemical formula 2 or chemical formula 3 below, 【Chemistry 1】 * is the part connected to A, k is an integer greater than or equal to 3, and n is an integer between 1 and 700. C is a substituent represented by chemical formula 4 or chemical formula 5 below. 【Chemistry 2】

2. The branched poly(3-hydroxypropionic acid) polymer according to claim 1, wherein the acid value of the branched poly(3-hydroxypropionic acid) polymer is 150 meq / kg or less.

3. In the aforementioned branched poly(3-hydroxypropionic acid) polymer, The branched poly(3-hydroxypropionic acid) polymer according to claim 1, wherein the number ratio of chemical formula 5 to the total of chemical formulas 4 and 5 is 5% or more.

4. The aforementioned polyfunctional monomer is Pentaerythritol, 4-arm-poly(ethylene glycol) n=2-10, di(trimethylolpropane), dipentaerythritol, tripentaerythritol, xylitol, sorbitol, inositol, cholic acid It contains one or more selected from the group consisting of (acid), β-cyclodextrin, tetrahydroxyperylene, pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid, and tetraacetylenepentaamine. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

5. The weight-average molecular weight of the branched poly(3-hydroxypropionic acid) polymer is 1,000 to 300,000. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

6. The number-average molecular weight of the branched poly(3-hydroxypropionic acid) polymer is 500 to 100,000. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

7. The polydispersity index of the branched poly(3-hydroxypropionic acid) polymer is 1.00 to 13.

0. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

8. The glass transition temperature (Tg) of the branched poly(3-hydroxypropionic acid) polymer is -40°C to -10°C. The melting point of the aforementioned branched poly(3-hydroxypropionic acid) polymer is 40°C to 100°C. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

9. The branched poly(3-hydroxypropionic acid) polymer contains 0.1 mol% to 25 mol% of tetravalent or higher functional groups derived from the polyfunctional monomer with respect to repeating units derived from 3-hydroxypropionic acid. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

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