Branched poly(3-hydroxypropionic acid) polymers

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 to Korean Patent Application No. 10-2022-0146011, filed November 4, 2022, Korean Patent Application No. 10-2022-0146014, filed November 4, 2022, Korean Patent Application No. 10-2023-0031735, filed March 10, 2023, and Korean Patent Application No. 10-2023-0150442, filed November 3, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to novel branched poly(3-hydroxypropionic acid) polymers. [Background technology]

[0003] Poly(3-hydroxypropionic acid) is a biodegradable polymer that is not only shatter-resistant but also has excellent mechanical properties and is attracting attention as an environmentally friendly material.

[0004] Generally, poly(3-hydroxypropionic acid) is produced by condensation polymerization of the monomer 3-hydroxypropionic acid (3-HP). Considering the possibility of industrial application, it is necessary to produce poly(3-hydroxypropionic acid) with excellent thermal stability. However, since the chain of poly(3-hydroxypropionic acid) contains an ester structure, which has a thermal decomposition temperature of about 220°C, there is a limit to how much thermal stability can be improved.

[0005] To improve the thermal stability, it is conceivable to produce a high molecular weight poly(3-hydroxypropionate). However, it is not easy to increase the molecular weight of the polymer through the polycondensation of the monomer 3-hydroxypropionic acid. For example, during the polycondensation process, dehydration may occur, converting the monomer reaction terminal into a vinyl group and terminating the polymerization, and / or a low molecular weight cyclic structure may be generated during the polycondensation process, resulting in problems such as an increase in viscosity during the polycondensation process.

[0006] In addition, in the case of 3HP polymers, there is also a problem that the high acid value reduces the polymer stability and makes it difficult to form a copolymer.

[0007] Therefore, there is a need to produce a polymer that has biodegradable properties, can be expected to have industrial applications, not only has a high production yield, but also has an appropriate level of acid value.

Summary of the Invention

Problems to be Solved by the Invention

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

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

[0010] Another object of the present application is to provide a poly(3-hydroxypropionic acid) polymer that is advantageous for industrial applications.

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

Means for Solving the Problems

[0012] Provided herein are branched poly(3-hydroxypropionic acid) polymers and methods for their production.

[0013] When biodegradable polymers (3HP) are produced by direct condensation polymerization of 3HP, it is not easy to increase the molecular weight. This is because the aforementioned side reactions occur during condensation polymerization. However, increasing the molecular weight of the polymer is closely related to industrial applications, so research into this is necessary.

[0014] In this regard, the present inventors have confirmed that when a polyfunctional compound described below is used, it is possible to easily increase the molecular weight, and it is easy to control the molecular weight for industrial applications.

[0015] Specifically, the polymer of Chemical Formula 1 described below can be produced through an ester reaction between a polyfunctional compound having 4 or more valences and 3-hydroxypropionic acid (3HP). The use of a polyfunctional compound having 4 or more valences that can provide sufficient reactive sites (cites) can provide sufficient polymerization reaction and molecular weight increase (compared to the use of a compound having 3 or less valences).

[0016] If the molecular weight of the polymer is insufficient, the polymer will not fully exhibit its physical properties, and therefore, in industrial applications, it must be considered to be mixed with other types of polymers. However, the polymer of Chemical Formula 1 of the present application, which contains units derived from a polyfunctional compound having a valence of 4 or more, can have a high molecular weight, and therefore can be used alone.

[0017] Furthermore, according to a specific embodiment, by controlling the content of the multifunctional compound and 3-hydroxypropionic acid, which react with each other under a certain reaction condition, within a certain range, it is possible to provide polymers having various grades of molecular weight, which can broaden the industrial application range of the polymer. In addition, since the polymer of the present application has a low acid value, it has high polymer stability and is also advantageous for forming a copolymer by additional reaction with other compounds.

[0018] Specific examples of the present invention are described in more detail below.

[0019] First, in this specification, the term "substituted or unsubstituted" means a group selected from the group consisting of deuterium, halogen, nitrile, nitro, hydroxy, carbonyl, ester, imide, amino, phosphine oxide, alkoxy, aryloxy, alkylthio, arylthio, alkylsulfoxy, arylsulfoxy, silyl, boron, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, aralkenyl, alkylaryl, alkylamine, aralkylamine, heteroarylamine, arylamine, arylphosphine, or heterocyclic groups containing one or more of N, O, and S atoms, or a group selected from the group consisting of two or more of the above-listed substituents. For example, the "substituent having two or more substituents connected" may be a biphenyl group. In other words, the biphenyl group may be an aryl group, and may be interpreted as a substituent having two phenyl groups connected.

[0020] In the present specification, the number of carbon atoms of the carbonyl group is not particularly limited, but it is preferable that the number of carbon atoms is 1 to 40. Specifically, the carbonyl group may have a compound having the following structure, but is not limited thereto. [ka]

[0021] In the present specification, the oxygen of 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 ester group may be a compound having the following structural formula, but is not limited thereto. [ka]

[0022] In the present specification, the number of carbon atoms of the imide group is not particularly limited, but is preferably 1 to 25. Specifically, the imide group may have a compound having the following structure, but is not limited thereto. [ka]

[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, and a phenylsilyl group.

[0024] In this specification, specific examples of the boron group include, but are not limited to, a trimethyl boron group, a triethyl boron group, a t-butyl dimethyl boron group, a triphenyl boron group, and a phenyl boron group.

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

[0026] 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 alkyl group has 1 to 20 carbon atoms. According to another embodiment, the alkyl group has 1 to 10 carbon atoms. According to another embodiment, the alkyl group has 1 to 6 carbon atoms. Exemplary 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, 5-methylhexyl, and the like.

[0027] 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 of the alkenyl group is 2 to 20. According to another embodiment, the number of carbon atoms of the alkenyl group is 2 to 10. According to another embodiment, the number of carbon atoms of 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, a stilbenyl group, and a styrenyl group.

[0028] In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, and 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. Specific 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 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. Examples of the monocyclic aryl group include, but are not limited to, a phenyl group, a biphenyl group, and a terphenyl group. Examples of the polycyclic aryl group include, but are not limited to, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, and a fluorenyl group.

[0030] In this specification, the fluorenyl group may be substituted, and two of the substituents may be bonded together to form a spiro structure. When the fluorenyl group is substituted, [ka] However, the present invention is not limited to these.

[0031] In the present specification, a heteroaryl group refers to a heterocyclic group containing one or more of O, N, Si, and S as a hetero element and having aromaticity, and the number of carbon atoms is not particularly limited, but preferably has 2 to 60 carbon atoms. 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, pyridopyrazinyl, pyrazinopyrazinyl, 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 in the aralkyl group, the aralkenyl group, the alkylaryl group, and the arylamine group is the same as the above-mentioned aryl group examples. In this specification, the alkyl group in the aralkyl group, the alkylaryl group, and the alkylamine group is the same as the above-mentioned alkyl group examples. In this specification, the heteroaryl in the heteroarylamine can be applied to the above-mentioned heterocyclic group explanation. In this specification, the alkenyl group in the aralkenyl group is the same as the above-mentioned alkenyl group examples. In this specification, the aryl group explanation can be applied to the above-mentioned aryl group except that the arylene is a divalent group. In this specification, the heterocyclic group explanation can be applied to the above-mentioned heteroarylene except that the heteroarylene is a divalent group. In this specification, the hydrocarbon ring is not a monovalent group, but is formed by bonding two substituents, but is the above-mentioned aryl group or cycloalkyl group explanation can be applied. In this specification, the heterocyclic ring is not a monovalent group, but is formed by bonding two substituents, but is the above-mentioned heterocyclic group explanation can be applied.

[0033] In addition, in the present specification, the polyfunctional compound can be mixed with a polyfunctional monomer or a polyfunctional additive, and the polyfunctional compound means, for example, a polyol having a 4- or higher functional group or reactive group (e.g., -OH).

[0034] According to one embodiment of the present invention, there is provided a branched poly(3-hydroxypropionic acid) polymer represented by the following Chemical Formula 1:

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

[0036] B is a substituent represented by the following Chemical Formula 2 or Chemical Formula 3,

Chem.

[0037] * is the part linked to A, k is an integer of 3 or more, and n is an integer of 1 to 700, C is a substituent represented by the following Chemical Formula 4 or Chemical Formula 5.

Chem.

[0038] At this time, "Branched" refers to a polymer of a monomer in which each functional group has 3 or more, or 4 or more, and the R part in Chemical Formula 1 is defined as a branched structure.

[0039] For example, the branched structure means,

Chem.

[0040] In one example, k in Chemical Formula 1 may be an integer of 4 or more, 5 or more, 6 or more, 7 or more, or 8 or more. Although not particularly limited, k in Chemical Formula 1 may be 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, 8 or less, or 6 or less.

[0041] In one example, R may be a tetravalent 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. At this time, 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] Further, 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 acid value range as described above, the branched polymer can have a stable state and is advantageous for the formation of a copolymer by reaction with other compounds. Therefore, the branched polymer of the present application can enable an expansion of the industrial application range. The acid value can be measured by titrating with a 0.02N potassium methoxide solution as a titrant, as in the experiments described later.

[0043] Meanwhile, the present inventors have also confirmed through experiments that when a polyhydric alcohol having 4 or more hydroxyl groups is used as a reaction additive to react with poly(3-hydroxypropionic acid), a bio-derived monomer, to form a novel branched poly(3-hydroxypropionic acid) polymer, it is possible to produce polymers having various molecular weights, various thermal properties, and excellent acrylic structures through the formation of vinyl groups at the ends of each branch chain of the poly(3-hydroxypropionic acid) polymer.

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

[0045] In addition, since the acrylic polymer is prepared using the polyfunctional monomer having a valence of 4 or more, the number of vinyl groups at the branch ends may be increased due to the formation of more chains than when a polyfunctional monomer having a valence of less than 4 is used. Therefore, the acrylic polymer can reduce or alleviate the brittleness relative to conventional acrylic polymers having similar molecular weights, and can also reduce Tg and Tm.

[0046] Specifically, acrylic polymers are 2 It is a derivative of CHCOOR and has a variety of uses such as fibers and adhesives.

[0047] In addition, when the existing conventional technology provides a poly(3-hydroxypropionic acid) polymer, which is a biodegradable polymer, it is produced by polymerizing P3HP having a hydroxy group at the chain end from poly(3-hydroxypropionic acid) so that polymerization initiation with 3HP or other monomers becomes possible, or only focuses on the aspect of physical property changes. Therefore, the poly(3-hydroxypropionic acid) polymer has limited structure and molecular weight and has limitations in realizing various physical properties (for example, thermal properties).

[0048] Thereby, in order to improve the usability of the acrylic polymer and impart various physical properties to the poly(3-hydroxypropionic acid) polymer, poly(3-hydroxypropionic acid), which is a bio-derived environmentally friendly monomer, is introduced. Also, for the vinylation treatment of the polymer chain end for acrylic structure formation, a polyhydric alcohol having a valency of 4 or more is used as a polyfunctional monomer to produce acrylic polymers with various molecular weights from low molecular weight to high molecular weight.

[0049] In addition, the produced acrylic polymer may be a branched poly(3-hydroxypropionic acid) polymer having a branched structure of 4 or more branches from a linear structure by using a polyhydric alcohol having a valency of 4 or more as a polyfunctional monomer. That is, introducing a polyhydric alcohol having a valency of 4 or more with the polyfunctional monomer can make the vinylation treatment of the chain end of the branched poly(3-hydroxypropionic acid) polymer easier. Therefore, since the polymer can be easily produced in various structures from linear to hyperbranched structures, the application fields of acrylic polymers can be expanded.

[0050] In addition, in the branched poly(3-hydroxypropionic acid) polymer, by additionally vinylating the hydroxy group at the polymer chain end by adding 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 various contents.

[0051] In addition, the branched poly(3-hydroxypropionic acid) polymer is an environmentally friendly biodegradable polymer and can have different thermal properties (Tg, Tm) depending on various polymer structures.

[0052] Therefore, the branched poly(3-hydroxypropionic acid) polymer having various acrylic polymer structures can be used in various fields as a radical polymerization monomer and an elastomer.

[0053] With this configuration, in the present specification, a polyhydric alcohol having 4 or more valences is used, and an acrylic polymer in which the molecular weight and particle structure of the branched poly(3-hydroxypropionic acid) polymer are diversified can be provided.

[0054] In addition, the weight average molecular weight of the branched poly(3-hydroxypropionic acid) polymer can be adjusted. For example, the weight average molecular weight can be adjusted to be 1,000 to 100,000 or more.

[0055] The branched poly(3-hydroxypropionic acid) polymer includes an acrylic polymer having one or more, preferably three or four or more polymer molecular chains, with some of the 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 Formula 5 to the total of Chemical Formula 4 and Chemical Formula 5, i.e., the branch 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] The ratio of the number of Chemical Formula 5 to the total number of Chemical Formula 4 and Chemical Formula 5 (branch end vinyl group content) may be the content in an unpurified or purified branched poly(3-hydroxypropionic acid) polymer.

[0058] When the branched poly(3-hydroxypropionic acid) polymer is purified, the content of vinyl groups at the branch ends of the polymer produced under the same conditions may be further increased. According to a preferred embodiment of the present invention, in the case of a purified branched poly(3-hydroxypropionic acid) polymer produced under the same conditions, the ratio of the number of Chemical Formula 5 to the total of Chemical Formula 4 and Chemical Formula 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 branch end of the polymer is less than 5%, the non-acrylic chain end exhibits properties similar to poly(3-hydroxypropionic acid) polymer that can initiate polymerization with 3HP or other monomers, making it difficult to achieve the desired effect.

[0060] Meanwhile, the ratio of the number of Chemical Formula 5 to the total number of Chemical Formula 4 and Chemical Formula 5 (branch end vinyl group content) can be determined by measuring the vinyl group structure at the polymer chain end using 1H-NMR.

[0061] Specifically, the vinyl group content at the branch end was determined by measuring the CH peak value ( <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> ) can be measured and calculated according to the following formula 1. [ka]

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

[0063] In this case, in the above formula 4 or 5, * may be a moiety that is linked to B.

[0064] The polymer is characterized in that 3-hydroxypropionic acid is condensation polymerized with a polyfunctional monomer, and the polyfunctional monomer is a polyhydric alcohol having a tetravalent or higher hydroxyl group.

[0065] As mentioned above, the branched polymer may be formed by the condensation polymerization of 3-hydroxypropionic acid with a polyfunctional compound. The type of the polyfunctional compound used in the production of the branched polymer is not particularly limited. For example, the polyfunctional compound may be pentaerythritol, 4-arm-poly(ethyleneglycol) n=2 to 10, di(trimethylolpropane), dipentaerythritol, tri(pentaerythritol), xylitol, sorbitol, inositol, cholic acid, β-cyclodextrin, tetrahydroxyperylene, pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid, and tetraacetylenepentamine. pentamine). [ka]

[0066] As mentioned above, the branched polymer comprises units derived from 3-hydroxypropionic acid; and 0.05 to 50 parts by weight of a polyfunctional compound per 100 parts by weight of the 3-hydroxypropionic acid. For example, the polymer may comprise 0.1 parts by weight or more, 1 parts 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 a polyfunctional compound per 100 parts by weight of the 3-hydroxypropionic acid. Or, the branched polymer may comprise 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 a polyfunctional compound per 100 parts by weight of the 3-hydroxypropionic acid. Within the above content range, a branched polymer that can achieve the intended objective can be produced. As confirmed in the experiments described below, a branched polymer with a high molecular weight can be obtained even with a low content of the multifunctional compound.

[0067] In one example, the branched polymer may be a product of condensation polymerization of 0.005 mol % or more of a polyfunctional compound relative to the content of 3-hydroxypropionic acid. In producing the branched polymer of the present application, the polyfunctional compound functions as an initiator, so that even a small content of the compound can sufficiently fulfill its function.

[0068] Specifically, 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 of the polyfunctional compound can be used to polymerize the branched polymer, relative to the content of 3-hydroxypropionic acid. Although not particularly limited, 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 above content range, a branched polymer capable of achieving the intended objectives can be produced.

[0069] In one example, the branched polymer may have a weight average molecular weight (Mw) ranging from 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. 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 an embodiment of the present application, when producing a branched polymer, the contents of reaction components (e.g., 3-hydroxypropionic acid and polyfunctional compound) and / or reaction conditions, etc., are controlled so that the branched polymer has various grades of molecular weight characteristics.

[0070] In one example, the branched polymer may have a number average molecular weight (Mn) ranging from 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. 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 an embodiment of the present application, the branched polymer can be produced by controlling the contents of the reaction components (e.g., 3-hydroxypropionic acid and the polyfunctional compound) and / or the reaction conditions, etc., so that the branched polymer has various grades of molecular weight characteristics.

[0071] In one embodiment, 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 the 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 an embodiment of the present application, when preparing a branched polymer, the branched polymer may have various grades of molecular weight by controlling the content of reactants (e.g., 3-hydroxypropionic acid and polyfunctional compound) and / or reaction conditions.

[0072] The methods for measuring the weight average molecular weight, number average molecular weight, and polydispersity index will be described in connection with the experiments described below.

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

[0074] Specifically, the method includes a step of polymerizing 3-hydroxypropionic acid with a polyfunctional compound having 4 or more valences to produce a branched poly(3-hydroxypropionic acid) polymer represented by the following chemical formula 1:

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

[0076] The structure of the polymer represented by Chemical Formula 1 to be provided by the method of the embodiment is the same as that of the branched poly(3-hydroxypropionic acid) polymer described above, and the specific types, contents, properties, etc. of the monomers or compounds forming the polymer are the same as those described above, so detailed description will be 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 generation 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 the present application. The catalyst that can be used may be, for example, an acid catalyst or a tin-based catalyst. The acid catalyst may be, for example, a sulfonic acid catalyst or may include the same, and the sulfonic acid catalyst may include p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, and / or p-xylene-2-sulfonic acid. In addition, the tin-based catalyst may be, for example, SnCl 2 or Sn(oct) 2 may also be used.

[0078] The catalyst can be used in a predetermined content range. For example, the polymerization may be carried out using the catalyst in a content 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 the 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. When the catalyst is used within the above content range, it may be advantageous to promote polymerization and suppress the generation of cyclic oligomers.

[0079] In one example, the polymerization may be performed in a vacuum state. Here, the vacuum state means a pressure state lower than atmospheric pressure, for example, a pressure state of 500 torr or less. Although not particularly limited, the polymerization may be performed at a pressure of 100 torr or less, 50 torr or less, 10 torr or less, 1 torr or less, or 0.1 torr or less.

[0080] In one example, the polymerization may be carried out at a temperature range of 50 to 150° C. Specifically, the polymerization may be carried out at 60° C. or more, 70° C. or more, 80° C. or more, 90° C. or more, or 100° C. or more, and 140° C. or less, 130° C. or less, 120° C. or less, 110° C. or less, or 100° C. 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] In one example, the polymerization may be carried out for 1 to 70 hours. Specifically, the polymerization carried out in the above vacuum state and temperature range 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 time period during which side reactions are suppressed and a sufficient yield is ensured.

[0082] In one embodiment, the method may further include a catalyst removal or crystallization step performed after the polymerization reaction. For example, the step may be performed by mixing an organic solvent with the branched polymer and forming a temperature condition 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. As a result, the catalyst is removed while the branched polymer is crystallized. The type of organic solvent used is not particularly limited, and any publicly-known organic solvent may be used.

[0083] In one embodiment, the method may further include an oligomerization step performed before the polymerization reaction. Specifically, the method may further include an oligomerization step performed at 50 to 100° C. and in a vacuum state (e.g., 100 torr or less, 50 torr or less, 10 torr or less). When the oligomerization step is performed, the occurrence of side reactions can be suppressed. The time for which the oligomerization reaction is performed is not particularly limited, and 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 embodiment, the method may further include a step of drying any one or more of the 3-hydroxypropionic acid and the polyfunctional compound before the polymerization or oligomerization reaction step. Such drying is considered to be performed when the reaction components (3-hydroxypropionic acid and / or the polyfunctional compound) are mixed in an aqueous solution state. The drying conditions are not particularly limited, but may be performed, for example, at 30 to 100° C. and in a vacuum state (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] Meanwhile, according to yet another embodiment of the present invention, there is provided a method for producing a branched poly(3-hydroxypropionic acid) polymer represented by the following Chemical Formula 1, which includes the steps of: polymerizing 3-hydroxypropionic acid with a multifunctional monomer having a hydroxy group with 4 or more valences to produce an acrylic primary polymer; and heat-treating the acrylic primary polymer to produce an acrylic secondary polymer.

[0086] The step of preparing the acrylic primary polymer is a step of preparing poly(3-hydroxypropionic acid) (P3HP) by primary condensation polymerization of 3-hydroxypropionic acid with a polyfunctional monomer having a hydroxy group of 4 or more.

[0087] The polyfunctional monomer may be used in an amount of 0.1 mol% to 25 mol% based on the content of the 3-hydroxypropionic acid. When the content of the polyfunctional monomer is 25 mol%, the number of hydroxyl groups in the tetrahydric polyalcohol may be the same as the number of 3-hydroxypropionic acid, which is a raw material.

[0088] Therefore, when polymerization is performed within the above 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) having a linear structure formed by condensation polymerization of only 3-hydroxypropionic acid increases, instead of the branched structure formed by the reaction of the polyfunctional monomer with 3-hydroxypropionic acid, which may not meet the object of the present invention.

[0089] In addition, if the content of the polyfunctional monomer exceeds 25 mol%, there are problems in that side reactions occur due to excessive addition, making it difficult to obtain acrylic polymers with various molecular weights, and the reaction time becomes long, resulting in reduced process efficiency.

[0090] Preferably, the content of the polyfunctional monomer is 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 content of the 3-hydroxypropionic acid. In this case, a polymer can be formed without the above-mentioned problems.

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

[0092] Preferably, the polymerization is carried out at 50° C. to 100° C. and 0.1 torr to 5 torr under an acid catalyst for 10 to 50 hours as a condensation reaction 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 during the preparation of the acrylic primary polymer can be suppressed.

[0094] For your reference, the reaction after oligomerization can be appropriately adjusted according to the content range of the polyfunctional monomer used. If an excessive amount of polyfunctional monomer is used, the reaction time may be extended, which may cause chain transfer as a side reaction and gelation, so the reaction time should be appropriately adjusted within about 24 hours.

[0095] The acid catalyst may be a sulfonic acid catalyst, which has the effect of promoting polymerization of 3-hydroxypropionic acid and suppressing the production 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 at 0.01 mol % to 1 mol % based on the 3-hydroxypropionic acid content, and may suitably be added at 0.1 to 0.3 mol % equivalent.

[0098] If the content of the acid catalyst is too small, less than 0.01 mol%, the reaction progresses slowly, whereas if the content of the acid catalyst is too large, more than 1 mol%, a side reaction may occur. The amount of the catalyst added may vary depending on the type of catalyst, and the content of the acid catalyst may be based on the sulfonic acid catalyst.

[0099] Therefore, by using the acid catalyst in the above range, polymerization can be promoted to produce acrylic polymers containing vinyl groups at the branched chain ends with various 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 of carrying out a secondary polymerization reaction of the acrylic primary polymer under high temperature conditions to form additional vinyl groups at the chain ends of the acrylic primary polymer, thereby producing acrylic secondary polymers having various structures and molecular weights. Through this step, a branched poly(3-hydroxypropionic acid) polymer represented by Chemical Formula 1 can be provided.

[0101] Preferably, the heat treatment may be carried out at 100° C. to 200° C. with or without stirring for 1 hour to 20 hours. The heat treatment time may be 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, and 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 more dominant than the formation of vinyl groups at the chain ends of the acrylic primary polymer, and an acrylic structure is not formed. If the heat treatment temperature exceeds 200°C, the excessively high temperature causes decomposition of the 3-hydroxypropionic acid, which increases side reactions. If the heat treatment time is less than 1 hour, 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 more than 20 hours, the reaction of forming vinyl groups at the chain ends of the polymer becomes saturated and is not effective.

[0103] The heat treatment may be performed in an inert atmosphere at a pressure of 0.1 to 760 torr or at normal pressure, and nitrogen, argon, etc. may be used as the composition of the inert atmosphere.

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

[0105] Meanwhile, the method may further include a step of dissolving the heat-treated acrylic secondary polymer in an organic solvent and then adding a non-solvent to purify the solution.

[0106] Through the purification, the purity of the polymer can be improved by removing impurities.

[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, the weight of the acrylic secondary polymer may exceed the solubility of the solvent, and the polymer may not dissolve. If the content of the organic solvent is more than 2,000 parts by weight, the crystallinity may decrease when a non-solvent is added.

[0108] The 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 content of the non-solvent is less than 10 parts by weight, the crystallinity of the polymer to be purified may be low, and if the content of the non-solvent is more than 500 parts by weight, the purity of the polymer may be low.

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

[0111] The purification step may be performed at a temperature of −10° C. to 100° C. If the purification temperature is less than −10° C., the solubility of the solvent in the polymer may be low, and the polymer may not be dissolved. If the purification temperature is more than 100° C., the boiling points of the solvent and non-solvent may be higher.

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

[0113] The filtering and drying methods are not limited, and methods well known in the art may be used.

[0114] In addition, if necessary, the method may further include a step of pretreating the 3-hydroxypropionic acid and the polyfunctional monomer independently at 50° C. to 100° C. and 100 torr or less before polymerization. Through the pretreatment step, moisture 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 pretreating the 3-hydroxypropionic acid at 50° C. to 100° C., 100 torr or less, or 60 to 100 torr, for 1 to 2 hours prior to polymerization.

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

[0117] For example, the branched polymers may be used, alone or mixed with other polymeric components, to form all or part of an article of interest, such as, for example, packaging, films, nonwovens, and / or injection molded articles.

[0118] As described above, since the present application can provide a high molecular weight branched polymer, the above-mentioned article can be formed alone. And according to the present application, since polymers having various grades of molecular weights can be provided, the industrial application range of the article containing the branched polymer can be further expanded.

Advantages of the Invention

[0119] In this specification, a biodegradable and branched poly(3-hydroxypropionic acid) polymer having a high molecular weight and advantageous for industrial applications can be provided.

Modes for Carrying Out the Invention

[0120] Hereinafter, embodiments of the present invention will be described in more detail with the following examples. However, the following examples are merely illustrative of the embodiments of the present invention, and the content of the present invention is not limited by 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 an RBF, and water was 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 p-TSA 295.6 mg (0.2 mol% with respect to 3HP) was used as a catalyst, and a polycondensation reaction was carried out at 90 °C and 1 torr vacuum for 30 hours 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 prepared in the same manner as in Example 1, except that di(trimethylolpropane) was used instead of pentaerythritol.

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

[0126] Example 5 A branched polymer was prepared 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 a 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 295.6 mg of p-TSA was used as a catalyst to carry out a condensation polymerization reaction at 80° C. under a vacuum of 1 torr for 20 hours to produce a linear polymer.

[0129] Comparative Example 2 A copolymer was produced in the same manner as in Comparative Example 1, except that the polymerization including the oligomerization reaction was carried out for 25 hours.

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

[0131] As a result of NMR analysis of the obtained copolymer, no peak was detected between 5.5 and 7.0 ppm, and therefore it was confirmed that the copolymer was substantially free of terminal vinyl groups.

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

[0133] (1) Evaluation of molecular weight by GPC (gel permeation chromatography) The molecular weight of each copolymer prepared in each step in the examples and comparative examples was evaluated using a Water e2695 model instrument and an Agilent Plgel mixed c and b column. The sample was prepared at 4 mg / ml and chloroform was used as a solvent, and 20 ul was injected. 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 by a cubic function)

[0134] (2) Vinyl group content at branch ends The CH peak value ( <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> ) was measured and calculated according to the following formula 1. [ka]

[0135] In the above formula 1, <1> is the CH peak value of the vinyl group of Chemical Formula 5 at the branch end of the branched poly(3-hydroxypropionic acid) polymer, <2> is the terminal beta CH peak value of the chemical formula 4 at the branch 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 it with 0.02N potassium methoxide solution as the titrant solution, using a Mettler Toledo T5 device with a DGi 116-solvent electrode. [Table 1]

[0137] As can be seen from Table 1 above, in Examples 1 to 5, the branched ends contain 5% or more vinyl groups, showing the diversity of polymer structures, and it is possible to prepare branched poly(3-hydroxypropionic acid) polymers having acrylic structures with a wide range of molecular weights and other thermal properties while maintaining their inherent physical properties.

[0138] According to the above examples, the polymer structure is diversified to have the desired branch structure of 4 or more by the formation of the branch terminal vinyl group and crosslinking between the branches during the heat treatment. If the polymer contains multiple terminal groups, it is possible to impart ductility to the polymer material and to lower Tm, and it is possible to minimize the problem of impurities remaining in the oligomer during polymer copolymerization such as PLH due to the inactivation of the -OH functional group contained in the polymer.

[0139] In contrast, it was confirmed that the copolymers obtained in Comparative Examples 1 and 2 had a relatively high acid value, and a relatively low weight average molecular weight and PDI value.

[0140] In addition, it was confirmed through NMR data that the copolymer obtained in Comparative Example 3 had no vinyl groups at its terminals because it was obtained by reacting pentaerythritol with lactic acid.

[0141] <Examples 6 to 12: Preparation of branched 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] 100g of pretreated 3-hydroxypropionic acid (3HP) and 0.2g of pentaerythritol as polyhydric alcohol were placed in a reactor, and 300mg of p-TSA (0.1mol% relative to 3HP) was used as an acid catalyst to carry out primary polymerization at 80°C for 20 hours or more to produce an acrylic primary polymer. The pressure inside the reactor during polymerization was maintained below 5 torr.

[0143] The prepared acrylic primary polymer (P3HP) was melted at 100°C, then heated to 150°C, and heat-treated for 2 hours in the presence of 300 mg of p-TSA (0.1 mol% relative to 3HP) as an acid catalyst to terminate the secondary polymerization reaction and produce a branched polymer of Formula 1 having vinyl groups at the chain ends (crude). The heat treatment was carried out at 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 90°C or less and 100 torr or less for 2 hours.

[0145] 50 g of pretreated 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 for 15 hours or more at 85° C. using 300 mg of p-TSA (0.3 mol % relative to 3HP) as an acid catalyst. The pressure inside the reactor during polymerization was maintained below 10 torr.

[0146] The prepared acrylic primary polymer (P3HP) was melted at 100°C, then heated to 170°C, and heat-treated for 10 hours or more in the presence of 200 mg of p-TSA (0.18 mol% relative to 3HP) as an acid catalyst to terminate the secondary polymerization reaction and produce a branched polymer of Formula 1 having vinyl groups at the chain ends. The heat treatment was carried out under normal 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 to remove water at 65°C and 70 torr for 2 hours.

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

[0149] The prepared acrylic primary polymer (P3HP) was melted at 100°C, heated to 140°C, and subjected to a secondary polymerization reaction for 5 hours under 0.6 torr pressure and 400 mg of p-TSA (0.18 mol% relative to 3HP) acid catalyst without stirring to produce a branched polymer of 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, and then heated to 150°C. The secondary polymerization reaction was carried out without stirring for more than 15 hours under 0.9 torr pressure and 80 mg (0.18 mol% relative to 3HP) of p-TSA as an acid catalyst 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 concentrated at 60 torr pressure and 80°C using 210 mg of p-TSA (0.18 mol% relative to 3HP) as an acid catalyst. After that, primary polymer polymerization was carried out for 21 hours at the same temperature (80°C) under high vacuum pressure of 1 to 2 torr.

[0153] The prepared acrylic primary polymer (P3HP) was heated to 180°C under a nitrogen atmosphere at normal pressure, and then heat-treated for 1 hour under an acid catalyst containing 210 mg of p-TSA (0.18 mol% relative to 3HP), and the secondary polymerization reaction was terminated to produce a branched polymer of Formula 1 having vinyl groups at the chain ends (crude).

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

[0155] Example 12 30 g of the branched polymer of 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 having vinyl groups at the chain ends.

[0157] <Experimental Example 2> The polymers prepared in Examples 6 to 12 were evaluated for their properties as follows. (1) Evaluation of molecular weight by GPC (gel permeation chromatography) The molecular weight of the polymers prepared in each step in the examples and comparative examples was evaluated using a Water e2695 model instrument and an Agilent Plgel mixed c and b column. The sample was prepared at 4 mg / ml and chloroform was used as a solvent, and 20 ul was injected. The weight average molecular weight (Mw), number average molecular weight (Mn), maximum peak molecular weight (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 by a cubic function)

[0158] (2) Vinyl group content at branch ends The CH peak value ( <1> ) and the terminal beta CH peak value of chemical formula 4 ( <2> ) was measured and calculated according to the following formula 1. [ka]

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

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

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

[0162] In addition, the sample was cooled from 150° C. to −80° C. at 10° C. / min (1st cooling), the temperature was maintained at −80° C. for 10 minutes, and the temperature was raised from −80° C. to 150° C. at 10° C. / min (2nd heating). [Table 2]

[0163] As can be seen from Table 2 above, Examples 6 to 12 contain 5% or more vinyl groups at the branch ends, showing the diversity of polymer structures, and it is possible to prepare branched poly(3-hydroxypropionic acid) polymers having acrylic structures with a wide range of molecular weights and other thermal properties while maintaining their inherent physical properties.

[0164] According to the above examples, it can be seen that the polymer structure having the desired 4 or more branch structures is diversified through the formation of vinyl groups at the branch terminals and crosslinking between the branches during heat treatment, and that the thermal properties are thereby improved, resulting in lower Tg and Tm compared to the comparative examples.

[0165] Generally, the faster the crystallization rate, the larger the enthalpy of Tc, and the less or no cold crystallization there is, while the higher the degree of crystallization, the larger the enthalpy of Tm. Higher crystallization also increases the strength of the material, but it is brittle and inelastic.

[0166] However, in the examples, the content of the vinyl groups at the ends of the branches can be adjusted in various ways to lower the Tm and the 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. [Chemical formula 1] R-[A-(B)n-C] ｋ In the above formula 1, R is a tetravalent or higher functional group derived from a polyfunctional monomer, A is 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 the following chemical formula 2 or 3: 【Chemistry 1】 * is a moiety linked to A, k is an integer of 3 or more, and n is an integer of 1 to 700, C is a substituent represented by the following Chemical Formula 4 or Chemical Formula 5. 【Chemistry 2】

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

3. The branched poly(3-hydroxypropionic acid) polymer, 2. The branched poly(3-hydroxypropionic acid) polymer according to claim 1, wherein the ratio of the number of the groups represented by Chemical Formula 5 to the total number of the groups represented by Chemical Formula 4 and Chemical Formula 5 is 5% or more.

4. The polyfunctional monomer is Pentaerythritol, 4-arm-poly(ethylene glycol) n = 2 to 10, di(trimethylolpropane), dipentaerythritol, tripentaerythritol, xylitol, sorbitol, inositol, cholic acid acid), β-cyclodextrin, tetrahydroxyperylene, pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid, and tetraacetylenepentamine; The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

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

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

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

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

8. The branched poly(3-hydroxypropionic acid) polymer has a glass transition temperature (Tg) of −40° C. to −10° C.; The melting point of the 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 a tetravalent or higher functional group derived from the polyfunctional monomer relative to a repeating unit derived from 3-hydroxypropionic acid. The branched poly(3-hydroxypropionic acid) polymer according to claim 1.

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