Branched poly (3-hydroxypropionic acid) polymers

Abstract

The present invention relates to branched poly (3-hydroxypropionic acid) polymers that can have biodegradability and high molecular weight and are advantageous for industrial applications.

Description

Technical Field

[0001] This application claims the benefit of Korean Patent Application No. 10-2022-0146011 filed in the Korean Intellectual Property Office on November 4, 2022, Korean Patent Application No. 10-2022-0146014 filed in the Korean Intellectual Property Office on November 4, 2022, Korean Patent Application No. 10-2023-0031735 filed in the Korean Intellectual Property Office on March 10, 2023, and Korean Patent Application No. 10-2023-0150442 filed in the Korean Intellectual Property Office on November 3, 2023, the disclosures of which are incorporated herein by reference in their entirety.

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

[0003] Poly(3-hydroxypropionic acid) is a biodegradable polymer that has attracted attention as an environmentally friendly material having resistance to brittle fracture and at the same time excellent mechanical properties.

[0004] Generally, poly(3-hydroxypropionic acid) is prepared by polycondensation of monomer 3-hydroxypropionic acid (3-HP). In addition, considering industrial applicability, it is necessary to prepare poly(3-hydroxypropionic acid) having excellent thermal stability. However, poly(3-hydroxypropionic acid) contains an ester structure in its chain, wherein the ester structure has limitations in improving thermal stability because the thermal decomposition temperature is about 220°C.

[0005] In order to improve thermal stability, it is possible to consider preparing poly(3-hydroxypropionate) with a high molecular weight. However, it is not easy to increase the molecular weight of the polymer by polycondensation of the monomer 3-hydroxypropionic acid. For example, dehydration may occur during the polycondensation process, which may cause the following problems: polymerization may terminate when the reactive end of the monomer is converted to a vinyl group, and / or low molecular weight cyclic structures may be formed during the polycondensation process, and viscosity increases during the polycondensation process.

[0006] Furthermore, the 3HP polymer has a problem in that the polymer stability is reduced due to its high acid value, making it difficult to form a copolymer.

[0007] Therefore, there is a need to prepare a polymer which not only has biodegradable properties, can be expected to be industrially applicable and has a high production yield, but also has an appropriate acid value level. Summary of the invention

[0008] Technical issues

[0009] One object of the present application is to provide a branched poly (3-hydroxypropionic acid) polymer having biodegradability.

[0010] Another object of the present application is to provide branched poly(3-hydroxypropionic acid) polymers having a high molecular weight.

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

[0012] Yet another object of the present application is to provide a method for preparing branched poly (3-hydroxypropionic acid) polymers.

[0013] Technical Solution

[0014] Provided herein are branched poly(3-hydroxypropionic acid) polymers and methods for making the same.

[0015] When 3HP is directly subjected to polycondensation to prepare biodegradable P(3HP), it is not easy to increase its molecular weight. This is because the above-mentioned side reactions occur during polycondensation. However, since increasing the molecular weight of polymer is greatly relevant to industrial application, it is necessary to study this problem.

[0016] In this regard, the present inventors have determined that when a polyfunctional compound described hereinafter is used, the molecular weight can be easily increased, and the molecular weight can be easily controlled for industrial applications.

[0017] Specifically, the polymer of Chemical Formula 1 described below can be prepared by an ester reaction between a tetravalent or higher-valent polyfunctional compound and 3-hydroxypropionic acid (3HP), wherein the use of a tetravalent or higher-valent polyfunctional compound capable of providing sufficient reaction sites can provide sufficient polymerization reaction and molecular weight increase (compared to the use of a trivalent or lower-valent compound).

[0018] If the molecular weight of the polymer is insufficient, it is difficult to fully exhibit the physical properties of the polymer, and therefore the polymer may be considered to be mixed with other types of polymers for industrial applications. However, the polymer of Chemical Formula 1 of the present application comprising units derived from a tetravalent or higher polyfunctional compound may have a high molecular weight and may therefore be used completely alone.

[0019] In addition, according to a specific embodiment, when the content between the multifunctional compound and 3-hydroxypropionic acid that react with each other under predetermined reaction conditions is controlled within a predetermined range, polymers with various molecular weights can be provided, and thus the industrial application range of the polymer can be further expanded. In addition, since the polymer of the present application has a low acid value, its polymer stability is high, and it is also conducive to forming a copolymer by further reaction with other compounds.

[0020] Specific embodiments of the present invention will be described in more detail below.

[0021] First, in the present disclosure, the term "substituted or unsubstituted" means unsubstituted or substituted with one or more substituents selected from the following: deuterium; halogen group; nitrile group; nitro group; hydroxyl group; carbonyl group; ester group; imide group; amino group; phosphine oxide group; alkoxy group; aryloxy group; alkylthio group; arylthio group; alkylsulfonyl group; arylsulfonyl group; silyl group; boron group; alkyl group; cycloalkyl group; alkenyl group; aryl group; aralkyl group; aralkenyl group; alkylaryl group; alkylamino group; aralkylamino group; heteroarylamino group; arylamino group; arylphosphino group; or a heterocyclic group containing at least one of N, O and S atoms, or unsubstituted or substituted with a substituent in which two or more substituents are connected among the substituents exemplified above. For example, "a substituent in which two or more substituents are connected" can be a biphenyl group. That is, the biphenyl group can be an aryl group, or it can be understood as a substituent in which two phenyl groups are connected.

[0022] In the present disclosure, the carbon number of the carbonyl group is not particularly limited, but is preferably 1 to 40. Specific examples thereof may be compounds having the following structural formula, but are not limited thereto.

[0023]

[0024] In the present disclosure, the ester group may have a structure in which the oxygen of the ester group may be substituted by a linear, branched or cyclic alkyl group having 1 to 25 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Specific examples thereof may be compounds having the following structural formula, but are not limited thereto.

[0025]

[0026] In the present disclosure, the carbon number of the imide group is not particularly limited, but is preferably 1 to 25.

[0027] Specific examples thereof may be compounds having the following structural formulas, but are not limited thereto.

[0028]

[0029] In the present disclosure, the silyl group specifically includes trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl and the like, but is not limited thereto.

[0030] In the present disclosure, the boryl group specifically includes a trimethylboryl group, a triethylboryl group, a tert-butyldimethylboryl group, a triphenylboryl group, and a phenylboryl group, but is not limited thereto.

[0031] In the present disclosure, examples of halogen groups include fluorine, chlorine, bromine, or iodine.

[0032] In the present disclosure, the alkyl group may be linear or branched, and its carbon number is not particularly limited, but is preferably 1 to 40. According to one embodiment, the carbon number of the alkyl group is 1 to 20. According to another embodiment, the carbon number of the alkyl group is 1 to 10. According to yet another embodiment, the carbon number of the alkyl group is 1 to 6. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, 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, but are not limited thereto.

[0033] In the present disclosure, the alkenyl group may be linear or branched, and the carbon number thereof is not particularly limited, but is preferably 2 to 40. According to one embodiment, the carbon number of the alkenyl group is 2 to 20. According to another embodiment, the carbon number of the alkenyl group is 2 to 10. According to yet another embodiment, the carbon number of the alkenyl group is 2 to 6. Specific examples thereof 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, phenyl group, styryl group, etc., but are not limited thereto.

[0034] In the present disclosure, the cycloalkyl group is not particularly limited, but its carbon number is preferably 3 to 60. According to one embodiment, the carbon number of the cycloalkyl group is 3 to 30. According to another embodiment, the carbon number of the cycloalkyl group is 3 to 20. According to yet another embodiment, the carbon number of the cycloalkyl group is 3 to 6. Specific examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl and the like, but are not limited thereto.

[0035] In the present disclosure, the aryl group is not particularly limited, but its carbon number is preferably 6 to 60, and it may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the carbon number of the aryl group is 6 to 30. According to one embodiment, the carbon number of the aryl group is 6 to 20. As a monocyclic aryl group, the aryl group may be phenyl, biphenyl, terphenyl, etc., but is not limited thereto. Polycyclic aryl groups include naphthyl, anthracenyl, phenanthrenyl, pyrenyl, base, fluorenyl, etc., but are not limited thereto.

[0036] In the present disclosure, the fluorenyl group may be substituted, and two substituents may be connected to each other to form a spirocyclic structure. In the case where the fluorenyl group is substituted,

[0037]

[0038] etc. However, the structure is not limited thereto.

[0039] In the present disclosure, the heteroaryl group is a heterocyclic group containing at least one of O, N, Si and S as a heteroatom and having aromaticity, and the carbon number thereof is not particularly limited, but is preferably 2 to 60. Examples of the heteroaryl group include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, Azolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzo oxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, benzofuranyl, phenanthroline, thiazolyl, isothiophene Azolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, dibenzofuranyl and the like, but not limited thereto.

[0040] In the present disclosure, the aryl in aralkyl, aralkenyl, alkylaryl and arylamine is the same as the example of aryl as defined above. In the present disclosure, the alkyl in aralkyl, alkylaryl and alkylamine is the same as the example of alkyl as defined above. In the present disclosure, the heteroaryl in heteroarylamine can be applied to the description of heterocyclic group as defined above. In the present disclosure, the alkenyl in aralkenyl is the same as the example of alkenyl as defined above. In the present disclosure, the description of aryl as defined above can be applied, except that arylene is a divalent group. In the present disclosure, the description of heterocyclic group as defined above can be applied, except that heteroarylene is a divalent group. In the present disclosure, the description of aryl or cycloalkyl as defined above can be applied, except that hydrocarbon ring is not a monovalent group but is formed by combining two substituents. In the present disclosure, the description of heterocyclic group as defined above can be applied, except that heterocycle is not a monovalent group but is formed by combining two substituents.

[0041] Furthermore, in the present disclosure, the polyfunctional compound may be used in combination with a polyfunctional monomer or a polyfunctional additive. Furthermore, the polyfunctional compound may mean, for example, a polyol having a tetravalent or higher valent functional group or a reactive group (eg, -OH).

[0042] According to one embodiment of the present invention, a branched poly(3-hydroxypropionic acid) polymer represented by the following Chemical Formula 1 may be provided.

[0043] [Chemical formula 1]

[0044] R-[A-(B)nC] k

[0045] Wherein in Chemical Formula 1,

[0046] R is a tetravalent or higher valent functional group derived from a multifunctional monomer,

[0047] A is a direct bond or a linking group derived from an ether, thioether, ester, thioester, ketone, sulfoxide, sulfone, sulfonate, amine, amide, imine, imide or carbamate,

[0048] B is a substituent represented by the following Chemical Formula 2 or Chemical Formula 3,

[0049] [Chemical formula 2]

[0050]

[0051] [Chemical formula 3]

[0052]

[0053] * is a portion connected to A, k is an integer of 3 or more, n is an integer of 1 to 700, and

[0054] C is a substituent represented by the following Chemical Formula 4 or Chemical Formula 5,

[0055] [Chemical formula 4]

[0056]

[0057] [Chemical formula 5]

[0058]

[0059] At this time, the branching is a polymer of monomers each having at least three or at least four functional groups, and the R portion in Chemical Formula 1 defines a branched structure.

[0060] For example, a branched structure may refer to the following structure:

[0061]

[0062] In each branching unit, n may independently have any integer value from 1 to 700.

[0063] In one embodiment, 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.

[0064] In one embodiment, R may be a tetravalent or higher valent linking group derived from a substituted or unsubstituted C1-60 alkyl group, a substituted or unsubstituted C3-60 cycloalkyl group, a substituted or unsubstituted C6-60 aryl group, or a substituted or unsubstituted C2-60 heteroaryl group containing at least one of N, O, and S. In this case, at least one of the carbon atoms of the alkyl group, cycloalkyl group, aryl group, and heteroaryl group may be substituted or unsubstituted with at least one heteroatom selected from N, O, and S or a carbonyl group.

[0065] In addition, the branched poly (3-hydroxypropionic acid) polymer satisfies an acid value of 150 milliequivalents / kg or less. Specifically, the acid value of the branched polymer can be, for example, 140 milliequivalents / kg or less, 135 milliequivalents / kg or less, 130 milliequivalents / kg or less, 125 milliequivalents / kg or less, 120 milliequivalents / kg or less, 115 milliequivalents / kg or less, 110 milliequivalents / kg or less, 105 milliequivalents / kg or less, 100 milliequivalents / kg or less, 95 milliequivalents / kg or less, 90 milliequivalents / kg or less. In some embodiments, the branched polymers of the present invention can have an acid value of 0.14N m / kg or lower, 0.16N m / kg or lower, 0.24N m / kg or lower, 0.34N m / kg or lower, 0.48N m / kg or lower, 0.54N m / kg or lower, 0.64N m / kg or lower, 0.70N m / kg or lower, 0.80N m / kg or lower, 0.90N m / kg or lower, 1.12N m / kg or lower, 1.25N m / kg or lower, 1.36N m / kg or lower, 1.48N m / kg or lower, 1.54N m / kg or lower, 1.64N m / kg or lower, 1.76N m / kg or lower, 1.88N m / kg or lower, 1.90N m / kg or lower, 1.13N m / kg or lower, 1.25N m / kg or lower, 1.26N m / kg or lower, 1.37N m / kg or lower, 1.48N m / kg or lower, 1.54N m / kg or lower, 1.64N m / kg or lower, 1.76N m / kg or lower, 1.88N m / kg or lower, 1.48N m / kg or lower, 1.54N m / kg or lower, 1.46N m / kg or lower, 1.54N m / kg or lower, 1.64N m / kg or lower,

[0066] At the same time, the present inventors have also confirmed through experiments that when a polyol having four or more hydroxyl groups is used as a reaction additive and reacted with poly(3-hydroxypropionic acid) which is a bio-derived monomer to form a new branched poly(3-hydroxypropionic acid) polymer, a vinyl group is formed at the end of each branch of the poly(3-hydroxypropionic acid) polymer, thereby enabling the preparation of polymers having various molecular weights, various thermal properties and excellent acrylic structures.

[0067] In particular, in the novel branched structure, a certain amount of vinyl groups are introduced into the chain ends, so that the molecular weight and particle structure of the acrylic polymer can be diversified. Therefore, the branched poly (3-hydroxypropionic acid) polymer represented by Chemical Formula 1 having a novel structure can be an acrylic polymer having vinyl groups at the branch ends.

[0068] In addition, since the acrylic polymer is provided using a tetravalent or higher polyfunctional monomer, chain formation can be further increased compared to the case of using a polyfunctional monomer having a valence lower than tetravalent, and the number of vinyl groups at branched ends can be increased. Therefore, the acrylic polymer can reduce or alleviate brittleness compared to conventional acrylic polymers having a similar molecular weight, and can also reduce Tg and Tm.

[0069] Specifically, the acrylic polymer is "CH 2=CHCOOR" derivatives and have various applications such as fibers and adhesives.

[0070] Furthermore, according to the existing prior art, when a poly(3-hydroxypropionic acid) polymer (P3HP) is provided as a biodegradable polymer, P3HP having a hydroxyl group at a chain end thereof is polymerized by poly(3-hydroxypropionic acid), which makes it possible to initiate polymerization with 3HP or other monomers, or to focus only on changing aspects of physical properties. Therefore, the poly(3-hydroxypropionic acid) polymer has a limited structure and molecular weight, and has limitations in achieving various physical properties (e.g., thermal properties).

[0071] In order to improve the usability of acrylic polymers and impart various physical properties to poly(3-hydroxypropionic acid) polymers, acrylic polymers having various molecular weights from low molecular weight to high molecular weight can be prepared by introducing poly(3-hydroxypropionic acid) which is a bio-derived, environmentally friendly monomer, and by using a tetravalent or higher polyol as a multifunctional monomer for vinylizing the polymer chain terminal for forming an acrylic structure.

[0072] In addition, by using a tetravalent or higher polyol as a multifunctional monomer, the prepared acrylic polymer can be a branched poly(3-hydroxypropionic acid) polymer having four or more branched structures from a linear structure. That is, the introduction of a tetravalent or higher polyol into the multifunctional monomer can promote the vinylation of the chain end of the branched poly(3-hydroxypropionic acid) polymer. Therefore, the polymer can be easily prepared into various structures from linear to hyperbranched structures, thereby expanding the application field of the acrylic polymer.

[0073] In addition, for branched poly(3-hydroxypropionic acid) polymers, the hydroxyl group at the polymer chain terminal can be further vinylated according to the acid catalyst addition and heat treatment conditions to adjust the formation of vinyl groups at the end of each branch chain to prepare acrylic polymer compounds with various contents.

[0074] Furthermore, the branched poly(3-hydroxypropionic acid) polymer is an environmentally friendly biodegradable polymer, and may have thermal properties (Tg, Tm) different from each other due to its various polymer structures.

[0075] Therefore, branched poly(3-hydroxypropionic acid) polymers having various acrylic polymer structures can be used in various ways (eg, free radical polymerization monomers and elastomers).

[0076] According to this configuration, an acrylic polymer in which the molecular weight and particle structure of the branched poly(3-hydroxypropionic acid) polymer are diversified can be provided by using a tetravalent or higher-valent polyol.

[0077] In addition, the weight average molecular weight of the branched poly(3-hydroxypropionic acid) polymer may be adjusted to have, for example, a weight average molecular weight of 1,000 to 100,000, or a weight average molecular weight not lower than that.

[0078] 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 in which a part of the terminal of the branch is formed of a vinyl group.

[0079] Specifically, in the branched poly(3-hydroxypropionic acid) polymer, the ratio of the number of Chemical Formula 5 relative to the sum of Chemical Formula 4 and Chemical Formula 5 (i.e., the branched terminal vinyl content) may be 5 wt % or more, 10 wt % or more, 20 wt % or more, 30 wt % or more, 40 wt % or more, 42 wt % or more, 45 wt % or more, 50 wt % or more, 52 wt % or more, 55 wt % or more, 100 wt % or less, 95 wt % or less, 90 wt % or less, 80 wt % or less, 75 wt % or less, 72 wt % or less, 70 wt % or less, 65 wt % or less, 60 wt % or less, or 56 wt % or less.

[0080] In addition, the ratio of the amount of Chemical Formula 5 to the sum of Chemical Formula 4 and Chemical Formula 5 (branched terminal vinyl content) may be the content in an unpurified or purified branched poly(3-hydroxypropionic acid) polymer.

[0081] When the branched poly (3-hydroxypropionic acid) polymer is purified, the branch terminal vinyl content of the polymer prepared under the same conditions can be further increased. According to a preferred embodiment of the present invention, in the case of a purified branched poly (3-hydroxypropionic acid) polymer prepared under the same conditions, the ratio of the amount of Chemical Formula 5 to the sum of Chemical Formula 4 and Chemical Formula 5 can be 55 wt% or more and 100 wt% or less.

[0082] At this time, if the vinyl content of Chemical Formula 5 at the branched end of the polymer is less than 5%, the chain end that is not an acrylic polymer exhibits characteristics similar to those of a poly(3-hydroxypropionic acid) polymer capable of initiating polymerization with 3HP or other monomers, which may make it difficult to achieve the desired expected effect.

[0083] Meanwhile, the ratio of the number of Chemical Formula 5 to the sum of Chemical Formula 4 and Chemical Formula 5 (branching terminal vinyl content) can be obtained by measuring the vinyl structure at the chain end of the polymer using 1H-NMR.

[0084] Specifically, the CH peak (①) of the vinyl group of Chemical Formula 5 and the terminal βC-H peak (②) of Chemical Formula 4 at the branched end of each polymer were measured using 1H-NMR, and the vinyl content at the branched end can be calculated according to the following Equation 1.

[0085]

[0086] [Equation 1]

[0087]

[0088] Wherein in Equation 1, ① is the CH peak of the vinyl group of Chemical Formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer, and ② is the terminal βC-H peak of Chemical Formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0089] At this time, in Chemical Formula 4 or Chemical Formula 5, * may be a portion connected to B.

[0090] The polymer is formed by polycondensation of 3-hydroxypropionic acid and a polyfunctional monomer, wherein the polyfunctional monomer is a tetravalent or higher polyol.

[0091] As mentioned above, the branched polymer can be formed by condensation polymerization of 3-hydroxypropionic acid and a polyfunctional compound. The type of polyfunctional compound that can be used to prepare the branched polymer is not particularly limited, but for example, the polyfunctional compound can include one or more selected from the following: pentaerythritol, 4-arm-poly(ethylene glycol) n=2 to 10, di(trimethylolpropane), di(pentaerythritol), tri(pentaerythritol), xylitol, sorbitol, inositol, cholic acid, β-cyclodextrin, tetrahydroxy Pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid and tetraacetylenepentamine.

[0092]

[0093] As mentioned above, the branched polymer comprises 3-hydroxypropionic acid; and units derived from 0.05 to 50 parts by weight of a polyfunctional compound relative to 100 parts by weight of 3-hydroxypropionic acid. For example, the polymer may comprise the polyfunctional compound in the following amounts (relative to 100 parts by weight of 3-hydroxypropionic acid): 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. The branched polymer may contain the polyfunctional compound in the following amounts (relative to 100 parts by weight of 3-hydroxypropionic acid): 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. Within the above content range, a branched polymer capable of achieving the desired purpose can be prepared. As determined in the experiments described below, branched polymers with high molecular weights can be obtained even when a small amount of polyfunctional compounds are used.

[0094] In one embodiment, the branched polymer may be a polymer in which 0.005 mol% or more of the polyfunctional compound undergoes polycondensation based on the content of 3-hydroxypropionic acid. In preparing the branched polymer of the present application, the above-mentioned polyfunctional compound plays a role similar to that of the initiator, and thus it can fully exert its role even in a small amount.

[0095] Specifically, the branched polymer may be polymerized using 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 based on the content of 3-hydroxypropionic acid. Although not particularly limited, its upper limit can be, for example, 25mol% or less, 20mol% or less, specifically, 15mol% or less, 14.5mol% or less, 14.0mol% or less, 13.5mol% or less, 13.0mol% or less, 12.5mol% or less, 12.0mol% or less, 11.5mol% or less, 11.0mol% or less, 10.5mol% or less, 10mol% or less, 9.5mol% or less, 9mol% or less, 8.5mol% or less, 8mol% or less, 7.5mol% or less, 7mol% or less, 6.5mol% or less, 6mol% or less, 5.5mol% or less, or 5.0mol% or less. Within the above content range, a branched polymer capable of achieving a desired purpose can be prepared.

[0096] In one embodiment, the weight average molecular weight (Mw) of the branched polymer may be in the range of 1,000 to 300,000. Specifically, the weight average molecular weight (Mw) of the polymer can 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. In addition, its upper limit can 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. In this way, according to one embodiment of the application, the content and / or reaction conditions of the reaction components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) are controlled during the preparation of the branched polymer so that the branched polymer can have various grades of molecular weight characteristics.

[0097] In one embodiment, the number average molecular weight (Mn) of the branched polymer may be in the range of 500 to 100,000. Specifically, the weight average molecular weight (Mn) of the polymer can 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. In addition, its upper limit can 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. In this way, according to one embodiment of the application, the content and / or reaction conditions of the reaction components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) are controlled during the preparation of the branched polymer so that the branched polymer can have various grades of molecular weight characteristics.

[0098] In one embodiment, the polydispersity index (PDI) of the branched polymer can be in the range of 1.0 to 13.0. Specifically, the polydispersity index (PDI) of the polymer can 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. In addition, its upper limit can 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. In this way, according to one embodiment of the application, the content and / or reaction conditions of the reaction components (e.g., 3-hydroxypropionic acid and polyfunctional compounds) are controlled during the preparation of the branched polymer so that the branched polymer can have various grades of molecular weight characteristics.

[0099] The methods used to measure weight average molecular weight, number average molecular weight and polydispersity index are explained in conjunction with the experiments described hereinafter.

[0100] According to other embodiments of the present invention, methods for preparing branched poly(3-hydroxypropionic acid) polymers may be provided.

[0101] Specifically, the method includes the step of polymerizing 3-hydroxypropionic acid with a tetravalent or higher-valent polyfunctional compound to prepare a branched poly(3-hydroxypropionic acid) polymer represented by the following Chemical Formula 1.

[0102] The branched poly (3-hydroxypropionic acid) polymer may satisfy an acid value of 150 milliequivalent / kg or less.

[0103] The structure of the polymer provided by the method of the above specific embodiment is the same as that of the above-mentioned branched poly(3-hydroxypropionic acid) polymer, and the specific types, contents, characteristics, etc. of the monomers or compounds forming the polymer are the same as those described above, and therefore a detailed description thereof will be omitted.

[0104] In one embodiment, polymerization can be carried out in the presence of a catalyst. It is beneficial to promote polymerization during the use of the catalyst and to suppress 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 or the realization of the technical theme of the present application. Available catalysts can be, for example, acid catalysts or tin-based catalysts. The acid catalyst can be, for example, a sulfonic acid catalyst, or can include a sulfonic acid catalyst. 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. In addition, for example, SnCl can be used. 2 or Sn(oct) 2 As a tin-based catalyst.

[0105] The catalyst can be used with a predetermined content range. For example, the catalyst can be used to carry out polymerization with an amount of 0.001mol% to 1.0mol% relative to 3-hydroxypropionic acid. Specifically, the content of the catalyst can be 0.01mol% or higher, 0.05mol% or higher or 0.1mol% or higher, and its upper limit can be, for example, 0.9mol% or lower, 0.8mol% or lower, 0.7mol% or lower, 0.6mol% or lower or 0.5mol% or lower. When the catalyst is used within the above-mentioned content range, it can be more conducive to promoting polymerization and suppressing the generation of cyclic oligomers at the same time.

[0106] In one embodiment, the polymerization can be carried out under a vacuum state. At this time, the vacuum state means a pressure state below atmospheric pressure, for example, it can mean a pressure state of 500 torr or less. Although not particularly limited, the polymerization can be carried out under 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.

[0107] In one embodiment, the polymerization may be performed at a temperature range of 50° C. to 150° C. Specifically, the polymerization may be performed at a temperature 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. At this time, the polymerization reaction temperature may be selected within a temperature range in which side reactions may be suppressed and sufficient yield may be ensured.

[0108] In one embodiment, polymerization can be carried out from 1 hour to 70 hours. Specifically, the polymerization carried out under the vacuum state mentioned above and the temperature range can be carried out for 2 hours or longer, 3 hours or longer, 4 hours or longer or 5 hours or longer, and 60 hours or shorter, 55 hours or shorter, 50 hours or shorter, 45 hours or shorter, 40 hours or shorter, 35 hours or shorter, 30 hours or shorter, 25 hours or shorter, 20 hours or shorter, 15 hours or shorter, 10 hours or shorter or 5 hours or shorter. Now, polymerization can be carried out and can suppress side reaction and can ensure the time of enough productive rates.

[0109] In one embodiment, the method may further include a catalyst removal or crystallization process step performed after the above-mentioned polymerization reaction. For example, the step may be performed by mixing the branched polymer with an organic solvent 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. Thus, the branched polymer is crystallized and the catalyst is removed. The type of organic solvent used is not particularly limited, and any known solvent may be used.

[0110] In one embodiment, the method may also include an oligomerization step performed before the above-mentioned polymerization reaction. Specifically, the method may also include an oligomerization step performed at 50°C to 100°C and in a vacuum state (e.g., 100 Torr or less, 50 Torr or less, 10 Torr or less). By undergoing the oligomerization step, the occurrence of side reactions can be suppressed. The time for performing such an oligomerization reaction 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 30 minutes or longer, or 60 minutes or longer.

[0111] In one embodiment, the method may further include a step of drying one or more of the 3-hydroxypropionic acid and the polyfunctional compound before polymerization or before the oligomerization step. This drying takes into account the situation where the reactive components (3-hydroxypropionic acid and / or polyfunctional compound) are mixed in aqueous solution. The drying conditions are not particularly limited, but for example, the drying can be carried out at 30° C. to 100° C. and under a vacuum state (about 50 torr to 300 torr) for a predetermined time, such as 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, or 1 hour or less.

[0112] Meanwhile, according to another embodiment of the present invention, a method for preparing a branched poly(3-hydroxypropionic acid) polymer represented by the following Chemical Formula 1 may be provided, the method comprising: a step of polymerizing 3-hydroxypropionic acid with a tetravalent or higher-valent multifunctional monomer to prepare an acrylic primary polymer, and a step of heat-treating the acrylic primary polymer to prepare an acrylic secondary polymer.

[0113] The step of preparing an acrylic primary polymer is a step of preparing poly(3-hydroxypropionic acid) (P3HP) by primary polycondensation of 3-hydroxypropionic acid and a polyfunctional monomer having a tetravalent or higher hydroxyl group.

[0114] The multifunctional monomer may be used in an amount of 0.1 mol% to 25 mol% relative to the content of 3-hydroxypropionic acid. When the content of the multifunctional monomer is 25 mol%, the number of hydroxyl groups in the tetravalent polyol may be equal to that in the 3-hydroxypropionic acid as a raw material.

[0115] Therefore, when the polymerization is carried out within the above content range, it is suitable to form a desired branched acrylic primary polymer structure as a suitable cross-linked structure with excellent yield. When the content of the multifunctional monomer is less than 0.1 mol%, the amount of poly(3-hydroxypropionic acid) having only a linear structure formed by polycondensation of 3-hydroxypropionic acid rather than a branched structure formed by the reaction of the multifunctional monomer with 3-hydroxypropionic acid increases, which may not meet the purpose of the present invention.

[0116] Furthermore, when the content of the multifunctional monomer exceeds 25 mol %, a side reaction proceeds due to excessive addition, which makes it difficult to obtain acrylic polymers having various molecular weights, and the reaction time becomes longer, which causes a problem of reduced process efficiency.

[0117] Preferably, the content of the multifunctional monomer can be 0.1mol% to 20mol%, 0.1mol% to 15mol%, 0.1mol% to 10mol%, 0.1mol% to 5mol%, 0.1mol% to 1mol% or lower, or 0.1mol% to 0.5mol% or lower, or 0.1mol% or higher, 0.5mol% or higher, or 1.0mol% or higher, or 20mol% or lower, 15mol% or lower, 10mol% or lower, 5mol% or lower, 1mol% or lower, or 0.5mol% or lower relative to the content of 3-hydroxypropionic acid. In this case, a polymer can be formed without the above problems.

[0118] The polymerization may be carried out at 50° C. to 100° C. and a pressure of 5 Torr or less for 10 hours or more under an acid catalyst.

[0119] Preferably, the polymerization can be carried out by condensation reaction under an acid catalyst at 50° C. to 100° C. and a pressure of 0.1 to 5 torr or less for 10 to 50 hours to prepare 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, or 50 hours or less, 45 hours or less, 40 hours or less, or 35 hours or less.

[0120] When the melt polymerization is performed under the above conditions, the generation of side reaction products during the production of the acrylic primary polymer can be suppressed.

[0121] For reference, the reaction after oligomerization can be appropriately adjusted according to the content range of the multifunctional monomer used. If an excessive amount of multifunctional monomer is used, the reaction time becomes longer, and a side reaction chain transfer may occur, and gelation may occur. The reaction time can be appropriately adjusted within about 24 hours.

[0122] In addition, the acid catalyst may be a sulfonic acid-based catalyst. The catalyst has the effect of promoting the polymerization of 3-hydroxypropionic acid and simultaneously suppressing the formation of cyclic oligomers during the polymerization process.

[0123] According to a specific embodiment of the present invention, the sulfonic acid-based catalyst may be p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid or p-xylene-2-sulfonic acid.

[0124] Preferably, the acid catalyst is used in an amount of 0.01 mol% to 1 mol% relative to the content of 3-hydroxypropionic acid, and may be appropriately added in an amount of 0.1 mol% equivalent to 0.3 mol% equivalent.

[0125] If the acid catalyst content is less than 0.01 mol%, which is a very small amount, the reaction proceeds slowly, and if the content is greater than 1 mol% and the catalyst is added excessively, a side reaction may proceed. The amount of the added catalyst may vary depending on the type of catalyst, and the content of the acid catalyst may be based on a sulfonic acid-based catalyst.

[0126] Therefore, by using the acid catalyst in the above range, polymerization can be promoted to produce acrylic polymers containing vinyl groups at the ends of the branches having various molecular weights and thermal characteristics. Preferably, the content of the sulfonic acid-based catalyst can 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, or 0.5 mol% or less, or 0.3 mol% or less.

[0127] The heat treatment is a step of further performing a secondary polymerization reaction of the acrylic primary polymer under high temperature conditions to further form a vinyl group at the chain end of the acrylic primary polymer, thereby preparing acrylic secondary polymers having various structures and molecular weights. Through the above steps, a branched poly (3-hydroxypropionic acid) polymer represented by Chemical Formula 1 can be provided.

[0128] Preferably, the heat treatment may be performed at 100° C. to 200° C. for 1 to 20 hours with or without stirring. The heat treatment time may be 1 hour or longer, 2 hours or longer, 3 hours or longer, 4 hours or longer, 20 hours or shorter, 15 hours or shorter, 10 hours or shorter, and 5 hours or shorter.

[0129] If the heat treatment temperature is lower than 100°C, polycondensation with 3-hydroxypropionic acid used as a raw material is more dominant than the formation of a vinyl group at the chain end of the acrylic primary polymer, and thus an acrylic structure cannot be formed. In addition, when the heat treatment temperature is higher than 200°C, 3-hydroxypropionic acid decomposes due to the excessively high temperature, which causes a problem of increased side reactions. In addition, if the heat treatment time is shorter than 1 hour, there is a problem that it may be difficult to measure the formation of a vinyl group at the chain end of the primary polymer, and a heat treatment time of 20 hours or more may cause a problem that the vinyl group formation reaction at the chain end of the polymer is saturated and thus ineffective.

[0130] In addition, the heat treatment may be performed under a pressure of 0.1 to 760 torr or under an inert atmosphere at normal pressure. Nitrogen, argon, or the like may be used to form the inert atmosphere.

[0131] In addition, the heat treatment may be performed in the presence of an acid catalyst. A catalyst may be used under the same conditions as in the preparation step of the acrylic primary polymer to promote further polymerization of the acrylic primary polymer, thereby preparing an acrylic secondary polymer having a desired molecular weight and structure.

[0132] Meanwhile, the method may further include the step of dissolving the heat-treated acrylic secondary polymer in an organic solvent and then purifying the polymer by adding a non-solvent.

[0133] Through purification, impurities in the polymer can be removed to increase purity.

[0134] The organic solvent may 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 exceeds the solubility of the solvent and the polymer may not dissolve. If the content of the organic solvent is higher than 2,000 parts by weight, there is a problem that the crystallinity may decrease when a non-solvent is added.

[0135] The organic solvent may be a hydrocarbon-based organic solvent such as chloroform, diethyl ether, n-hexane, and toluene.

[0136] 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, there is a problem in that the crystallinity of the polymer to be purified is reduced, and if the content of the non-solvent exceeds 500 parts by weight, there is a problem in that the purity of the polymer may be reduced.

[0137] The non-solvent can be ethanol, water, methanol, isopropanol, etc.

[0138] The purification step may be performed at a temperature of -10° C. to 100° C. If the purification temperature is lower than -10° C., there is a problem that the solubility of the solvent to the polymer decreases and may not be dissolved, while if the purification temperature exceeds 100° C., there may be a problem that the temperature is higher than the boiling points of the solvent and the non-solvent.

[0139] Furthermore, in the purification step, the precipitated acrylic secondary polymer is filtered and then dried at room temperature under vacuum conditions, so that a purified branched poly(3-hydroxypropionic acid) polymer can be provided in the form of particles.

[0140] The filtering and drying methods are not limited, and any method known in the art may be used.

[0141] In addition, if necessary, the method may further include a step of pretreating 3-hydroxypropionic acid and the multifunctional monomer independently at 50° C. to 100° C. and 100 Torr or less pressure before polymerization. By the pretreatment step, moisture present in 3-hydroxypropionic acid and the multifunctional monomer may be removed.

[0142] Preferably, the method may further include a step of pre-treating the 3-hydroxypropionic acid at 50° C. to 100° C. and a pressure of 100 Torr or less, or 60 Torr to 100 Torr for 1 to 2 hours before the polymerization.

[0143] According to yet another embodiment of the present invention, an article comprising the branched poly(3-hydroxypropionic acid) polymer may be provided.

[0144] For example, the branched polymer can be used alone or mixed with other polymer components to form all or part of a desired application article. Such articles can include, for example, packaging materials, films, nonwoven fabrics and / or injection molded products.

[0145] As mentioned above, the present application can provide a branched polymer with a high molecular weight, which can be used alone to form the above-mentioned products. In addition, according to the present application, polymers with various grades of molecular weight can be provided, thereby broadening the industrial application range of products containing the branched polymer.

[0146] Beneficial Effects

[0147] The present invention can provide a branched poly(3-hydroxypropionic acid) polymer that can have biodegradability and a high molecular weight and is advantageous for industrial applications. DETAILED DESCRIPTION

[0148] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are for illustrative purposes only, and the scope of the present invention is not intended to be limited by the following Examples.

[0149] <Examples 1 to 5: Preparation of branched copolymers>

[0150] Example 1

[0151] 3-Hydroxypropionic acid (3HP) and pentaerythritol dissolved in water were added to the RBF, and the moisture was dried at 90° C. and 100 Torr for 2 hours.

[0152] 70 g of dried 3-hydroxypropionic acid (3HP) and 0.154 g of pentaerythritol were placed in a reactor, and polycondensation was performed at 90° C. and under a vacuum of 1 Torr for 30 hours using 295.6 mg (0.2 mol % relative to 3HP) of p-TSA as a catalyst to prepare a branched copolymer.

[0153] Example 2

[0154] A branched copolymer was prepared in the same manner as in Example 1, except that dipentaerythritol was used instead of pentaerythritol.

[0155] Example 3

[0156] A branched copolymer was prepared in the same manner as in Example 1, except that di(trimethylolpropane) was used instead of pentaerythritol.

[0157] Example 4

[0158] A branched copolymer was prepared in the same manner as in Example 1, except that tripentaerythritol was used instead of pentaerythritol.

[0159] Example 5

[0160] A branched copolymer was prepared in the same manner as in Example 1, except that sorbitol was used instead of pentaerythritol.

[0161] <Comparative Examples 1 to 3>

[0162] Comparative Example 1

[0163] 3-Hydroxypropionic acid (3HP) dissolved in water was added to the RBF, and the water was dried at 90°C and 100 Torr for 2 hours.

[0164] 60 g of dried 3-hydroxypropionic acid (3HP) was placed in a reactor, and a polycondensation reaction was performed using 295.6 mg of p-TSA as a catalyst at 80° C. and under a vacuum of 1 Torr for 20 hours to prepare a linear copolymer.

[0165] Comparative Example 2

[0166] A copolymer was prepared in the same manner as in Comparative Example 1, except that the total polymerization time (including oligomerization reaction) was performed for 25 hours.

[0167] Comparative Example 3

[0168] Pentaerythritol (7.7 g), SnO (tin (II) oxide, 1.0 g), and lactic acid (300 g) were added to the RBF and reacted at 150° C. and 30 mbar for 15 hours to polymerize the copolymer.

[0169] As a result of NMR analysis of the obtained copolymer, it was confirmed that no peak was detected between 5.5 ppm and 7.0 ppm, and substantially no terminal vinyl group was contained.

[0170] <Experimental Example 1>

[0171] The properties of the branched polymers prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated as follows.

[0172] (1) Evaluation of molecular weight by GPC (gel permeation chromatography)

[0173] For the copolymer of each step prepared in the embodiment and the comparative example, use Water e2695 type instrument and Agilent Plgel Mixed-C and B column to evaluate molecular weight.Use chloroform as solvent to prepare 4mg / ml sample, and inject 20ul.Measure weight average molecular weight, number average molecular weight and polydispersity index by gel permeation chromatography (gel permeation chromatography, GPC, Tosoh ECO SECElite).The results are shown in the following table 1.

[0174] Solvent: Chloroform (eluent)

[0175] Flow rate: 1.0ml / min

[0176] Column temperature: 40°C

[0177] Standard: Polystyrene (calibrated with cubic function)

[0178] (2) Vinyl content at the branch end

[0179] The CH peak (①) of the vinyl group of Chemical Formula 5 and the terminal βC-H peak (②) of Chemical Formula 4 at the branched end of each polymer were measured using 1H-NMR, and the vinyl content was calculated according to the following Equation 1.

[0180]

[0181] [Equation 1]

[0182]

[0183] Wherein in Equation 1, ① is the CH peak of the vinyl group of Chemical Formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer, and ② is the terminal βC-H peak of Chemical Formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0184] (3) Measurement of acid value (unit: milliequivalent / kg)

[0185] The polymer was titrated with 0.02 N potassium methoxide solution and the titration point was analyzed. At this time, a DGi 116-solvent electrode was used in a Mettler Toledo T5 apparatus.

[0186] [Table 1]

[0187]

[0188] As can be seen in Table 1, Examples 1 to 5 contain a vinyl group content of 5% or more in the branched ends and thus exhibit diversity in polymer structure, making it possible to prepare branched poly(3-hydroxypropionic acid) polymers of acrylic structure having a wide range of molecular weights and other thermal properties while maintaining their inherent physical properties.

[0189] According to the embodiment, during the heat treatment, the polymer structure having a desired four or more branched structure is diversified by the formation of vinyl groups at the branched ends and crosslinking between the branches. If the polymer contains a large number of terminal groups, it is possible to impart ductility to the polymer material and have the effect of lowering Tm. The -OH functional group contained in the polymer is inactivated, thereby minimizing the problem of impurities remaining in the oligomer during copolymerization of the polymer such as PLH.

[0190] In contrast, it was determined that the copolymers obtained in Comparative Examples 1 and 2 had relatively high acid values ​​and relatively low weight average molecular weights and PDI values.

[0191] Furthermore, it was confirmed by NMR data that the copolymer obtained in Comparative Example 3 was obtained by reacting pentaerythritol with lactic acid, and thus no vinyl group was generated at the terminal.

[0192] <Examples 6 to 12: Preparation of branched copolymers>

[0193] Example 6

[0194] A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round bottom flask (RBF) and pretreated at 80° C. and a pressure of 100 Torr or less for 2 hours.

[0195] 100 g of pretreated 3-hydroxypropionic acid (3HP) and 0.2 g of pentaerythritol as a polyol were placed in a reactor, and primary polymer polymerization was performed at 80° C. for 20 hours or more using 300 mg of p-TSA (0.1 mol% relative to 3HP) as an acid catalyst. During the polymerization, the pressure inside the reactor was maintained at less than 5 Torr.

[0196] The prepared acrylic primary polymer (P3HP) was melted at 100°C, then heated to 150°C, and heat-treated for 2 hours under 300 mg of an acid catalyst p-TSA (0.1 mol% relative to 3HP) to terminate the secondary polymerization reaction. Thus, a branched polymer (crude product) of Chemical Formula 1 having a vinyl group at the chain end was prepared. The heat treatment was performed at less than 5 Torr.

[0197] Example 7

[0198] 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 at a pressure of 100 Torr or less for 2 hours.

[0199] 50 g of pretreated 3-hydroxypropionic acid (3HP) and 0.1 g of pentaerythritol as a polyol were placed in a reactor, and primary polymer polymerization was performed at 85° C. for 15 hours or more using 300 mg of p-TSA (0.3 mol% relative to 3HP) as an acid catalyst. During the polymerization, the pressure inside the reactor was maintained at less than 10 Torr.

[0200] The prepared acrylic primary polymer (P3HP) was melted at 100°C, then heated to 170°C, and heat-treated for 10 hours or more under 200 mg of an acid catalyst p-TSA (0.18 mol% relative to 3HP) to terminate the secondary polymerization reaction. Thus, a branched polymer of Chemical Formula 1 having a vinyl group at the chain end was prepared. The heat treatment was performed under normal pressure (crude product).

[0201] Example 8

[0202] A solution of 3-hydroxypropionic acid (3HP) dissolved in water was placed in a round bottom flask (RBF), and the water was dried at 65° C. and 70 Torr for 2 hours and concentrated.

[0203] 100 g of pretreated 3-hydroxypropionic acid (3HP) and 0.3 g of pentaerythritol as a polyol were placed in a reactor, and primary polymer polymerization was carried out at 95° C. and 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.

[0204] The prepared acrylic primary polymer (P3HP) was melted at 100° C., then heated to 140° C., heat-treated without stirring at a pressure of 0.6 Torr and 400 mg of an acid catalyst p-TSA (0.18 mol% relative to 3HP), and subjected to a secondary polymerization reaction for 5 hours. Thus, a branched polymer (crude product) of Chemical Formula 1 having a vinyl group at the chain end was prepared.

[0205] Example 9

[0206] A small amount (2 g to 3 g) of the primary polymer (P3HP) polymerized in Example 8 was placed in a vial reactor, melted at 90° C., heated to 150° C., and heat-treated for 15 hours or more at a pressure of 0.9 Torr and 80 mg of an acid catalyst p-TSA (0.18 mol % relative to 3HP) to allow a secondary polymerization reaction to proceed without stirring to prepare a branched polymer having a vinyl group at the chain end (crude product).

[0207] Example 10

[0208] 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.

[0209] 55 g of concentrated 3-hydroxypropionic acid (3HP) and 0.2 g of pentaerythritol as a polyol were placed in a reactor and concentrated using 210 mg of p-TSA (0.18 mol% relative to 3HP) as an acid catalyst at 60 Torr and 80° C. Then, primary polymer polymerization was performed at the same temperature (80° C.) and a high vacuum pressure of 1 to 2 Torr for 21 hours.

[0210] The prepared acrylic primary polymer (P3HP) was heated to 180°C under nitrogen atmosphere at normal pressure, and then heat-treated for 1 hour under 210 mg of an acid catalyst p-TSA (0.18 mol% relative to 3HP) to terminate the secondary polymerization reaction. Thus, a branched polymer (crude product) of Chemical Formula 1 having a vinyl group at the chain end was prepared.

[0211] Embodiment 11

[0212] A branched polymer having a vinyl group at the chain end was prepared in the same manner as in Example 10, except that the primary polymer polymerization time was changed to 25 hours.

[0213] Example 12

[0214] 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.

[0215] The precipitated polymer was filtered and dried in a vacuum oven (10 Torr) at room temperature overnight to prepare a purified branched polymer having a vinyl group at the chain end.

[0216] <Experimental Example 2>

[0217] The properties of the polymers prepared in Examples 6 to 12 were evaluated as follows.

[0218] (1) Evaluation of molecular weight by GPC (gel permeation chromatography)

[0219] For the multipolymer of each step prepared in embodiment and comparative example, use Water e2695 type instrument and Agilent Plgel Mixed-C and B column to assess molecular weight.Use chloroform as solvent to prepare the sample of 4mg / ml, and inject 20ul.Measure weight average molecular weight, number average molecular weight and polydispersity index by gel permeation chromatography (GPC, Tosoh ECO SEC Elite).The results are shown in the following table 1.

[0220] Solvent: Chloroform (eluent)

[0221] Flow rate: 1.0ml / min

[0222] Column temperature: 40°C

[0223] Standard: Polystyrene (calibrated with cubic function)

[0224] (2) Vinyl content at the branch end

[0225] The CH peak (①) of the vinyl group of Chemical Formula 5 and the terminal βC-H peak (②) of Chemical Formula 4 at the branched end of each polymer were measured using 1H-NMR, and the vinyl content was calculated according to the following Equation 1.

[0226]

[0227] [Equation 1]

[0228]

[0229] Wherein in Equation 1, ① is the CH peak of the vinyl group of Chemical Formula 5 at the branched end of the branched poly(3-hydroxypropionic acid) polymer, and ② is the terminal βC-H peak of Chemical Formula 4 at the branched end of the branched poly(3-hydroxypropionic acid) polymer.

[0230] (3) Evaluation of thermal properties by DSC (differential scanning calorimetry)

[0231] For the copolymers of each step prepared in the embodiments and comparative examples, thermal properties (Tg, Tm, Tcc (cold crystallization, second heating result), Tc (first cooling result)) were measured using TADSC250 equipment under nitrogen flow, and the results are shown in Table 2 below.

[0232] Each copolymer was heated / cooled at a rate of 10°C / min in the temperature range of -80°C to 150°C to perform a thermal scan.

[0233] Furthermore, the sample was cooled from 150°C to -80°C at 10°C / min (first cooling) / kept at -80°C for 10 minutes, and heated from -80°C to 150°C at 10°C / min (second heating).

[0234] [Table 2]

[0235]

[0236] As can be seen in Table 2, Examples 6 to 12 contain vinyl groups in an amount of 5% or more in the branched ends, showing diversity in polymer structure, making it possible to prepare branched poly(3-hydroxypropionic acid) polymers of acrylic structure having a wide range of molecular weights and other thermal properties while maintaining their inherent physical properties.

[0237] According to the Examples, during heat treatment, a polymer structure having a desired four or more branched structure is diversified through the formation of vinyl groups at branched ends and crosslinking between branches, and as a result, Tg and Tm are lower than those of Comparative Examples due to thermal characteristics.

[0238] In addition, generally, when the crystallization rate is fast, the enthalpy of Tc is large, and cold crystallization is small or non-existent. The higher the crystallinity, the greater the enthalpy of Tm may be. In addition, the higher the crystallinity, the higher the strength of the material, but it is brittle and has no elasticity.

[0239] However, in embodiments, the content of the vinyl group at the branching end may be adjusted in various ways to reduce Tm and reduce the crystallinity of the branched structure, thereby reducing the brittle characteristics.

Claims

1. A branched poly (3-hydroxypropionic acid) polymer represented by the following chemical formula 1: [Chemical formula 1] R-[A-(B)nC] k Wherein in Chemical Formula 1, R is a tetravalent or higher valent functional group derived from a multifunctional monomer, A is a direct bond or a linking group derived from an ether, thioether, ester, thioester, ketone, sulfoxide, sulfone, sulfonate, amine, amide, imine, imide or carbamate, B is a substituent represented by the following Chemical Formula 2 or Chemical Formula 3, [Chemical formula 2] [Chemical formula 3] * is a portion connected to A, k is an integer of 3 or more, n is an integer of 1 to 700, and C is a substituent represented by the following Chemical Formula 4 or Chemical Formula 5, [Chemical formula 4] [Chemical formula 5] 2. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: The branched poly(3-hydroxypropionic acid) polymer has an acid value of 150 milliequivalents / kg or less.

3. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: In the branched poly (3-hydroxypropionic acid) polymer, The amount ratio of Chemical Formula 5 to the sum of Chemical Formula 4 and Chemical Formula 5 is 5% or more.

4. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: The multifunctional monomer includes one or more selected from the following: pentaerythritol, 4-arm-poly(ethylene glycol) n=2 to 10, di(trimethylolpropane), di(pentaerythritol), tri(pentaerythritol), xylitol, sorbitol, inositol, bile acid, β-cyclodextrin, tetrahydroxy , pyridine-tetraamine (PTA), diethylenetriaminepentaacetic acid and tetraacetylenepentamine.

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

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

7. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: The branched poly(3-hydroxypropionic acid) polymer has a polydispersity index of 1.00 to 13.

0.

8. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: The branched poly(3-hydroxypropionic acid) polymer has a glass transition temperature (Tg) of -40°C to -10°C, and The branched poly (3-hydroxypropionic acid) polymer has a melting point of 40°C to 100°C.

9. The branched poly (3-hydroxypropionic acid) polymer according to claim 1, wherein: The branched poly(3-hydroxypropionic acid) polymer includes 0.1 mol% to 25 mol% of a tetravalent or higher-valent functional group derived from the multifunctional monomer, relative to the repeating unit derived from 3-hydroxypropionic acid.

Images