Poly(3-hydroxypropionic acid) and its manufacturing method

Abstract

The present invention enables the production of poly(3-hydroxypropionic acid) having a low vinyl group ratio in terminal groups and a high molecular weight by producing poly(3-hydroxypropionic acid) through condensation polymerization of 3-hydroxypropionic acid under specific conditions.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0000713, filed January 3, 2023, Korean Patent Application No. 10-2023-0016271, filed February 7, 2023, and Korean Patent Application No. 10-2023-0193117, filed December 27, 2023, and all contents disclosed in the documents of these Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to poly(3-hydroxypropionic acid) having a low vinyl group ratio in the terminal groups and a high molecular weight, and a method for producing the same. [Background technology]

[0003] Poly(3-hydroxypropionic acid) has biodegradable properties, and due to its environmentally friendly properties, research using it has been actively conducted recently.

[0004] Methods for producing poly(3-hydroxypropionic acid) can be broadly classified into two types: one is a petrochemical-based method using β-propiolactone (PL) for polymerization, and the other is a bio-based method using 3-hydroxypropionic acid (3HP).

[0005] The use of PL requires multiple synthesis steps using ethylene oxide, which is economically disadvantageous compared to the use of 3HP. Additionally, poly(3-hydroxypropionic acid) produced using PL has a 0% biocontent and a high vinyl end group ratio due to the use of acrylic acid, which contains a vinyl group, as an initiator.

[0006] When polymerizing using 3HP biosynthesis, multiple steps such as freeze-drying, ultrasonication, and solvent elution must be performed to obtain poly(3-hydroxypropionic acid), which requires the use of large amounts of solvent. In the case of biosynthesis polymerized in this way, the biocontent of poly(3-hydroxypropionic acid) is 100%, but it contains a large amount of organic nitrogen due to the residues remaining after fermentation, resulting in a high YI (yellow index).

[0007] To solve this problem, attempts have been made to polycondense 3HP, but the production of high-molecular-weight poly(3-hydroxypropionic acid) is limited by the production of cyclic oligomers as by-products. Attempts have also been made to increase the molecular weight by ROP of low-molecular-weight cyclic oligomers, but separation and purification are difficult.

[0008] Therefore, there is a demand for a method for producing poly(3-hydroxypropionic acid) by condensation polymerization of 3HP, which has a low vinyl group ratio in the terminal groups and a high molecular weight. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to provide poly(3-hydroxypropionic acid) having a low proportion of vinyl groups in the terminal groups and a high molecular weight.

[0010] The present invention also provides a method for producing the poly(3-hydroxypropionic acid). [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides a poly(3-hydroxypropionic acid) copolymer containing a repeating unit represented by the following chemical formula 1, wherein the poly(3-hydroxypropionic acid) has a vinyl group ratio of 40 mol % or less among its terminal groups. [ka]

[0012] The term "poly(3-hydroxypropionic acid)" used in the present invention refers to a polymer containing repeating units derived from 3-hydroxypropionic acid, specifically, a polymer containing repeating units represented by Chemical Formula 1 above.

[0013] Poly(3-hydroxypropionic acid) has biodegradable properties due to the molecular structure of the repeating unit. Furthermore, the poly(3-hydroxypropionic acid) according to the present invention is characterized in that the ratio of vinyl groups among the terminal groups is 40 mol % or less, obtained by condensation polymerization of 3-hydroxypropionic acid under specific conditions as described below.

[0014] Poly(3-hydroxypropionic acid) may contain terminal groups such as hydroxy, carboxy, and vinyl groups. However, the production method of the present invention, which involves producing poly(3-hydroxypropionic acid) from 3-hydroxypropionic acid by condensation polymerization (described below), is less likely to produce poly(3-hydroxypropionic acid) with vinyl groups than conventional methods for producing poly(3-hydroxypropionic acid) from β-propiolactone. Vinyl groups are generated as a side reaction during the polymerization of 3-hydroxypropionic acid with poly(3-hydroxypropionic acid). This can disrupt the equivalence ratio of functional groups (hydroxyl and carboxy) during condensation polymerization, which is crucial for achieving high molecular weight polymers. Furthermore, the presence of vinyl groups in poly(3-hydroxypropionic acid) can prevent proper chain extension of poly(3-hydroxypropionic acid) through additional modification. Therefore, the poly(3-hydroxypropionic acid) of the present invention has an advantage that the above-mentioned drawbacks are fundamentally reduced since it has few vinyl groups at the terminal groups.

[0015] Preferably, the poly(3-hydroxypropionic acid) has a vinyl group ratio of 40 mol% or less, 39 mol% or less, 38 mol% or less, 37 mol% or less, 36 mol% or less, 35 mol% or less, 30 mol% or less, 25 mol% or less, 20 mol% or less, 15 mol% or less, 10 mol% or less, 8 mol% or less, or 6 mol% or less among its terminal groups. Furthermore, the poly(3-hydroxypropionic acid) is superior the lower the vinyl group ratio among its terminal groups. For example, the poly(3-hydroxypropionic acid) has a vinyl group ratio of 0.1 mol% or more, 0.2 mol% or more, 0.3 mol% or more, 0.4 mol% or more, or 0.5 mol% or more among its terminal groups.

[0016] The vinyl group content of the poly(3-hydroxypropionic acid) was determined using NMR (equipped with a Buker 500 MHz NMR model): 1The ratio of vinyl groups to all end groups can be calculated by H-NMR measurement. Specifically, the polymer is dissolved in d-CDCl3 at a concentration of 8 mg / ml and the measurement is performed, and the ratio can be calculated using the following equation 1.

number

[0017] That is, the poly(3-hydroxypropionic acid) according to the present invention is characterized in that it is produced by condensation polymerization of 3-hydroxypropionic acid under specific conditions, thereby producing poly(3-hydroxypropionic acid) having a low vinyl group ratio in the terminal groups and a high molecular weight.

[0018] The poly(3-hydroxypropionic acid) may have a nitrogen content of 100 ppm or less. For example, the poly(3-hydroxypropionic acid) may have a nitrogen content of 80 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 38 ppm or less, 35 ppm or less, 33 ppm or less, 30 ppm or less, 1 ppm or more and 29 ppm or less, or 3 ppm or more and 28 ppm or less.

[0019] Furthermore, the poly(3-hydroxypropionic acid) may have a YI (yellow index) value of 30 or less. For example, the poly(3-hydroxypropionic acid) may have a YI (yellow index) value of 28 or less, 27 or less, 25 or less, 23 or less, 20 or less, 19 or less, 18 or less, 17 or less, 15 or less, 13 or less, or 12 or less, or may have a YI (yellow index) value of 1 or more, 2 or more, or 3 or more. The YI (yellow index) value of the poly(3-hydroxypropionic acid) may be the YI value measured on a film prepared using the poly(3-hydroxypropionic acid), and in this case, the thickness of the film may be, for example, 180 μm.

[0020] Biosynthetic polymerization of 3-hydroxypropionic acid requires multiple steps, such as freeze-drying, ultrasonication, and solvent elution, and also has the drawback of containing a large amount of organic nitrogen due to the residues remaining after fermentation, resulting in a high yellow index (YI). However, the poly(3-hydroxypropionic acid) of the present invention is produced by condensation polymerization of 3-hydroxypropionic acid under specific conditions. This eliminates the need for a purification process, and produces poly(3-hydroxypropionic acid) with a low nitrogen content and YI, as well as a low vinyl group ratio at the terminals and a high molecular weight, as described above.

[0021] Furthermore, the poly(3-hydroxypropionic acid) according to the present invention can be produced from 3-hydroxypropionic acid, which can be produced by biosynthesis. Therefore, the poly(3-hydroxypropionic acid) can have a biocarbon content of 80% by weight or more. For example, the poly(3-hydroxypropionic acid) can have a biocarbon content of 85% by weight or more, 90% by weight or more, 95% by weight to 100% by weight or less, or 100% by weight.

[0022] The biocarbon content refers to the biocarbon content relative to the total carbon content in poly(3-hydroxypropionic acid), with a higher value corresponding to a more environmentally friendly compound. Measurement methods include graphitizing or converting carbon atoms contained in the target compound into carbon dioxide gas, and measuring them using a mass spectrometer according to ASTM D6866-22, or liquid flash spectroscopy. In this case, the mass spectrometer can be used in conjunction with an accelerator to separate 14C ions from 12C ions to separate the two isotopes, and the content and content ratio can be measured using a mass spectrometer.

[0023] Preferably, the weight-average molecular weight of the poly(3-hydroxypropionic acid) according to the present invention is 10,000 to 700,000. More preferably, the weight-average molecular weight of the poly(3-hydroxypropionic acid) according to the present invention is 10,000 or more, 13,000 or more, 15,000 or more, 17,000 or more, or 20,000 or more, and 650,000 or less, 630,000 or less, 600,000 or less, 580,000 or less, 550,000 or less, 530,000 or less, 500,000 or less, 450,000 or less, 400,000 or less, 380,000 or less, 350,000 or less, or 300,000 or less.

[0024] Preferably, the number-average molecular weight of the poly(3-hydroxypropionic acid) according to the present invention is 7,000 to 500,000. More preferably, the number-average molecular weight of the poly(3-hydroxypropionic acid) according to the present invention is 7,000 or more, 8,000 or more, 9,000 or more, 10,000 or more, or 11,000 or more, and 450,000 or less, 400,000 or less, 380,000 or less, 360,000 or less, 350,000 or less, 330,000 or less, 300,000 or less, 200,000 or less, 150,000 or less, 130,000 or less, or 100,000 or less.

[0025] Preferably, the molecular weight distribution (Mw / Mn) of the poly(3-hydroxypropionic acid) according to the present invention is 1.2 to 3.5. More preferably, the molecular weight distribution of the poly(3-hydroxypropionic acid) according to the present invention is 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, or 2.0 or more, and 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, or 3.0 or less.

[0026] According to another embodiment of the present invention, the method includes polymerizing 3-hydroxypropionic acid at a temperature of 100° C. or less to produce poly(3-hydroxypropionic acid),

[0027] The poly(3-hydroxypropionic acid) has a vinyl group ratio of 40 mol % or less among its terminal groups.

[0028] In the method for producing the poly(3-hydroxypropionate), 3-hydroxypropionic acid can be polymerized at a temperature of 100°C or less, 95°C or less, 90°C or less, 85°C or less, 80°C or less, 75°C or less, or 70°C or less to produce the poly(3-hydroxypropionate). Such poly(3-hydroxypropionate) may be the poly(3-hydroxypropionate) according to the embodiment.

[0029] The polymerization may be solid-state polymerization carried out at a temperature of 70° C. or less. For example, 3-hydroxypropionic acid may be solid-state polymerized at a temperature of 70° C. or less to produce the poly(3-hydroxypropionic acid).

[0030] The present inventors have confirmed that when 3-hydroxypropionic acid is subjected to solid-state polymerization while inducing crystallization by lowering the temperature below its crystallization temperature, for example, to 70°C or below, it is possible to produce poly(3-hydroxypropionic acid) while minimizing side reactions, and that the produced poly(3-hydroxypropionic acid) has a low vinyl group ratio at the terminal groups, a low yellow index (YI) value, and a low nitrogen content.

[0031] The solid-state polymerization may be carried out at a temperature equal to or lower than the crystallization temperature of 3-hydroxypropionic acid, for example, 70°C or lower, 65°C or lower, 60°C or lower, 55°C or lower, or 50°C or lower, or 25°C or higher, 30°C or higher, 35°C or higher, or 40°C or higher.

[0032] The solid-state polymerization includes the steps of: (Step 1) solid-state polymerizing 3-hydroxypropionic acid at a temperature of 70° C. or less to produce an oligomer; and

[0033] The method may include a step (Step 2) of solid-state polymerizing the oligomer at a temperature of 70° C. or less to produce the poly(3-hydroxypropionic acid).

[0034] Step 1 may be a step of producing an oligomer by solid-state polymerization of 3-hydroxypropionic acid at a temperature of 70°C or less. The solid-state polymerization is carried out at a temperature below the crystallization temperature of the 3-hydroxypropionic acid, for example, 70°C or less, so that the reactant 3-hydroxypropionic acid and the product 3-hydroxypropionic acid oligomer can maintain a solid state. For example, the solid-state polymerization in Step 1 may be carried out at a temperature of 70°C or less, 65°C or less, 60°C or less, 55°C or less, or 50°C or less, or at a temperature of 25°C or more, 30°C or more, 35°C or more, or 40°C or more.

[0035] The oligomer produced in step 1 may have a weight-average molecular weight of 1,000 or more and 20,000 or less. Preferably, the weight-average molecular weight of the oligomer may be 1,500 or more, 2,000 or more, 2,500 or more, or 3,000 or more, and 15,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, or 70,000 or less.

[0036] Step 1 may be carried out at a pressure of 1 to 200 torr for 1 to 10 hours. For example, Step 1 may be carried out under a pressure of 1 torr or more, 5 torr or more, 7 torr or more, or 10 torr or more, and 200 torr or less, 150 torr or less, 100 torr or less, 70 torr or less, or 50 torr or less. The reaction time for Step 1 may be appropriately adjusted taking into account the molecular weight and yield of the produced oligomer, and is preferably 1 to 10 hours, 2 to 8 hours, or 3 to 5 hours.

[0037] Step 2 can include solid-state polymerizing the oligomer to produce the poly(3-hydroxypropionic acid).

[0038] Alternatively, Step 2 may be carried out at a temperature of 70° C. or less and a pressure of 0.01 torr to 5.00 torr for 20 to 100 hours. For example, the reaction temperature in Step 2 may be 70° C. or less, 65° C. or less, 60° C. or less, 55° C. or less, or 50° C. or less, or may be 25° C. or more, 30° C. or more, 35° C. or more, or 40° C. or more. The pressure in step 2 may be 5.00 torr or less, 4.00 torr or less, 3.00 torr or less, 2.00 torr or less, 1.00 torr or less, 0.50 torr or less, 0.40 torr or less, or 0.30 torr or less, and 0.01 torr or more, 0.02 torr or more, 0.03 torr or more, 0.04 torr or more, 0.05 torr or more, 0.06 torr or more, 0.07 torr or more, 0.08 torr or more, 0.09 torr or more, or 0.10 torr or more. The reaction time in step 2 may be appropriately adjusted taking into account the molecular weight and yield of the produced polymer, and is preferably 30 to 90 hours, 40 to 80 hours, or 50 to 70 hours.

[0039] Meanwhile, since step 2 is carried out after step 1, the catalyst added in step 1 can also participate in the reaction in step 2.

[0040] Also provided is a production method including the steps of melt-polymerizing 3-hydroxypropionic acid to produce a 3-hydroxypropionic acid oligomer (Step A) and polymerizing the 3-hydroxypropionic acid oligomer produced in Step 1 (Step B). By adjusting the production conditions for Steps A and B, the aforementioned poly(3-hydroxypropionate) can be produced.

[0041] Step A is a step of melt-polymerizing 3-hydroxypropionic acid to produce 3-hydroxypropionic acid oligomers. Melt polymerization refers to maintaining the reactant 3-hydroxypropionic acid and the product 3-hydroxypropionic acid oligomers in a liquid state. In particular, the reaction temperature is controlled to 100°C or less, typically between 80°C and 100°C. Preferably, the reaction temperature in Step A is 81°C or more, 82°C or more, 83°C or more, 84°C or more, or 85°C or more, and 99°C or less, 98°C or less, 97°C or less, 96°C or less, or 95°C or less. Step A is also carried out at a pressure of 5 torr to 20 torr. Preferably, Step A is 6 torr or more, 7 torr or more, 8 torr or more, or 9 torr or more, and 19 torr or less, 18 torr or less, 17 torr or less, 16 torr or less, or 15 torr or less. The reaction time of step A can be appropriately adjusted in consideration of the molecular weight of the 3-hydroxypropionic acid oligomer to be produced, the yield, etc., and is preferably 1 to 3 hours.

[0042] Step B of the present invention is a step in which the 3-hydroxypropionic acid oligomer prepared in Step A is further polymerized to produce poly(3-hydroxypropionate). Unlike Step A, since the reactant is an oligomer, the reaction is carried out at a lower pressure. In particular, the vinyl group content of the final poly(3-hydroxypropionate) is affected by the reaction conditions in Step B. Therefore, by adjusting the reaction temperature, reaction pressure, and reaction time in Step B, poly(3-hydroxypropionate) with a low vinyl group content and a high molecular weight can be produced.

[0043] Preferably, the reaction temperature in step B is 100°C or less, between 75°C and 95°C. If the reaction temperature is less than 75°C, polymerization will not proceed normally, resulting in a problem of a small molecular weight of poly(3-hydroxypropionate). If the reaction temperature is more than 100°C, poly(3-hydroxypropionate) with a high vinyl group content will be produced. More preferably, the reaction temperature in step B is 80°C or more, or 85°C or more, and 94°C or less, 93°C or less, 92°C or less, or 91°C or less.

[0044] Preferably, the reaction pressure in Step B is 5 mbar or less. More preferably, the pressure in Step B is 4 mbar or less, 3 mbar or less, 2 mbar or less, 1 mbar or less, 0.5 mbar or less, 0.4 mbar or less, or 0.3 mbar or less, and 0.01 mbar or more, 0.02 mbar or more, 0.03 mbar or more, 0.04 mbar or more, 0.05 mbar or more, 0.06 mbar or more, 0.07 mbar or more, 0.08 mbar or more, 0.09 mbar or more, or 0.1 mbar or more.

[0045] The reaction time of step B can be appropriately adjusted taking into consideration the molecular weight and yield of the resulting poly(3-hydroxypropionate), and is preferably 5 to 30 hours. Within this reaction time, the molecular weight of the resulting poly(3-hydroxypropionate) can be increased to an appropriate level, and the production yield can also be improved. More preferably, the reaction time of step B is 12 to 28 hours.

[0046] Meanwhile, since step B is performed after step A, the catalyst added in step A also participates in the reaction in step B. Therefore, the catalyst described in step A can also be used in step B.

[0047] The polymerization is carried out in the presence of a catalyst, and the catalyst can be used in an amount of 0.4 mol% or less relative to the 3-hydroxypropionic acid. For example, the catalyst can be used in an amount of 0.01 mol% or more, 0.02 mol% or more, 0.03 mol% or more, 0.04 mol% or more, or 0.05 mol% or more to 0.4 mol% or less relative to the 3-hydroxypropionic acid. If the amount of the catalyst used is too small, the polymerization will not proceed properly, resulting in a problem of a small molecular weight of poly(3-hydroxypropionate). If the amount of the catalyst used is too large, the poly(3-hydroxypropionate) will have a high vinyl group content.

[0048] The catalyst may be a sulfonic acid catalyst, a tin catalyst, a titanium catalyst, etc., and may be, but is not limited to, a sulfonic acid catalyst. The sulfonic acid catalyst may be p-toluenesulfonic acid (p-TSA), methanesulfonic acid (MsOH), m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, or p-xylene-2-sulfonic acid (p-XSA).

[0049] In the method for producing poly(3-hydroxypropionic acid) according to another embodiment, 3-hydroxypropionic acid is subjected to solid-state polymerization at a temperature of 70°C or less, and a polymerization catalyst is used in an amount of 0.4 mol% or less relative to the 3-hydroxypropionic acid, so that the final produced poly(3-hydroxypropionic acid) may have a vinyl group ratio of 40 mol% or less among its terminal groups.

[0050] In addition, in the method for producing poly(3-hydroxypropionic acid), 3-hydroxypropionic acid is melt-polymerized at a temperature of 100°C or less, and a polymerization catalyst is used in an amount of 0.4 mol% or less relative to the 3-hydroxypropionic acid, so that the proportion of vinyl groups among the terminal groups in the final produced poly(3-hydroxypropionic acid) can be 40 mol% or less.

[0051] The method may further include drying the 3-hydroxypropionic acid before polymerizing the 3-hydroxypropionic acid at a temperature of 100° C. or less to produce poly(3-hydroxypropionic acid). For example, the drying temperature may be 50° C. or more, 60° C. or more, 70° C. or more, 80° C. or more, or 90° C. or more, and 150° C. or less, 140° C. or less, 130° C. or less, 120° C. or less, or 110° C. or less. The drying may be performed under a pressure of 10 torr or more, 20 torr or more, 30 torr or more, or 40 torr or more, and 760 torr or less, 500 torr or less, 400 torr or less, 300 torr or less, or 200 torr or less. [Effects of the Invention]

[0052] As described above, the present invention enables the production of poly(3-hydroxypropionic acid) having a low vinyl group ratio in terminal groups and a high molecular weight by producing poly(3-hydroxypropionic acid) by condensation polymerization of 3-hydroxypropionic acid under specific conditions. DETAILED DESCRIPTION OF THE INVENTION

[0053] Hereinafter, the embodiments of the present invention will be described in more detail with reference to 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 to the following examples.

[0054] Example 1 (Step 1) 60 g of dehydrated 3-hydroxypropionic acid was placed in a reactor, and 0.2 mol% of p-TSA (p-Toluenesulfonic acid) was added as a catalyst to the 3-hydroxypropionic acid. The temperature and pressure in the reactor were maintained at 90°C and 10 torr, respectively, and melt polymerization was carried out for 2 hours to produce 3-hydroxypropionic acid oligomer.

[0055] (Step 2) Then, the temperature and pressure in the reactor were adjusted to 80° C. and 0.2 torr, respectively, and the reaction was carried out for 24 hours to produce poly(3-hydroxypropionate).

[0056] Examples 2 to 10 Poly(3-hydroxypropionate) was prepared by the same melt polymerization method as in Example 1, but the reaction conditions were changed as shown in Table 1 below.

[0057] Example 11 15 g of 3-hydroxypropionic acid and 63.3 mg of p-toluenesulfonic acid (p-TSA) catalyst (0.2 mol % based on 3-hydroxypropionic acid) were placed in an oil bath reactor and subjected to solid-state polymerization reaction at 70°C and 10 torr for 2 hours, followed by solid-state polymerization reaction at 70°C and 0.2 torr for 60 hours to obtain poly(3-hydroxypropionic acid).

[0058] Example 12 15 g of 3-hydroxypropionic acid and 126.6 mg of p-toluenesulfonic acid (p-TSA) catalyst (0.4 mol % based on 3-hydroxypropionic acid) were placed in an oil bath reactor and subjected to solid-state polymerization reaction at 70°C and 10 torr for 2 hours, followed by solid-state polymerization reaction at 70°C and 0.2 torr for 60 hours to obtain poly(3-hydroxypropionic acid).

[0059] Example 13 15 g of 3-hydroxypropionic acid and 32.01 mg of methanesulfonic acid (0.2 mol% based on 3-hydroxypropionic acid) were added to an oil bath reactor and solid-state polymerized at 70°C and 10 torr for 2 hours, followed by an additional 2 hours at 70°C and 0.2 torr. The temperature was then lowered to room temperature to induce crystallization, and the crystallized reactant was solid-state polymerized at 70°C and 0.2 torr for 60 hours to obtain poly(3-hydroxypropionic acid).

[0060] Example 14 15 g of 3-hydroxypropionic acid and 64.02 mg of methanesulfonic acid (0.4 mol% based on 3-hydroxypropionic acid) were added to an oil bath reactor and solid-state polymerized at 70°C and 10 torr for 2 hours, followed by an additional 2 hours at 70°C and 0.2 torr. The temperature was then lowered to room temperature to induce crystallization, and the crystallized reactant was subjected to solid-state polymerization at 70°C and 0.2 torr for 60 hours to obtain poly(3-hydroxypropionic acid).

[0061] Comparative Example 1 β-propiolactone (19.4 ml) was placed in a reactor, followed by acrylic acid (10 μL, 0.05 mol%) and Sn(Oct) 2 (9 μL, 0.01 mol%), and the mixture was reacted at 100° C. for 1 hour to produce a polymer. Comparative Example 2

[0062] The polymer was produced with reference to Korean Patent Publication No. 10-2021-0037448. Specifically, the culture medium used was a modified Riesenberg (MR) medium supplemented with ampicillin at a concentration of 0.2 g / L, and a 5 L fermentor (internal volume: 3 L) was used. The fermentation microorganism was recombinant E. coli produced by transforming XL1-Blue E. coli with a recombinant vector containing the RecC gene, a polyhydroxyalkanoate synthase (PHA synthase) derived from Ralstonia eutropha, and the propionyl-CoA transferase mutant 540 (CPPCT_540) gene derived from Clostridium propionicum, cloned into the pBLuescript II KS+ vector. The CPPCT_540 gene was modified by substituting the 193rd amino acid, valine, for alanine (V194A), and by introducing three silent mutations (T669C, A1125G, T1158C) without any amino acid changes (WO 09 / 022797). A feeding solution containing antibiotics and 700 g / L glucose was continuously added to the MR medium throughout the fermentation to produce poly(3-hydroxypropionic acid). Comparative Examples 3 to 5

[0063] Poly(3-hydroxypropionate) was prepared in the same manner as in Example 1, except that the reaction conditions were changed as shown in Table 1 below.

[0064] Comparative Example 6 15 g of 3-hydroxypropionic acid and 126.6 mg of p-toluenesulfonic acid (p-TSA) catalyst (0.4 mol % based on 3-hydroxypropionic acid) were placed in an oil bath reactor and subjected to solid-state polymerization reaction at 90°C and 10 torr for 2 hours, followed by solid-state polymerization reaction at 110°C and 0.2 torr for 24 hours to obtain poly(3-hydroxypropionic acid).

[0065] Comparative Example 7 15 g of 3-hydroxypropionic acid and 64.02 mg of methanesulfonic acid (0.4 mol % based on 3-hydroxypropionic acid) were placed in an oil bath reactor and subjected to solid-state polymerization reaction at 90°C and 10 torr for 2 hours, followed by solid-state polymerization reaction at 110°C and 0.2 torr for 24 hours to obtain poly(3-hydroxypropionic acid).

[0066] Experimental example The physical properties of the polymers prepared in the examples and comparative examples were evaluated by the following methods. 1) Weight average molecular weight and molecular weight distribution The weight average molecular weight, number average molecular weight, and polydispersity index of the copolymers prepared in each step in the examples and comparative examples were measured by gel permeation chromatography (GPC, Waters Alliance e2695). -Solvent: chloroform(eluent) -Flow rate: 1.0ml / min -Column temperature: 40℃ -Standard: Polystyrene 2) Analysis of vinyl end groups Using a Buker 500MHz NMR model, 1 The ratio of vinyl groups to all end groups was calculated by H-NMR measurement. Specifically, each polymer was dissolved in d-CDCl at a concentration of 8 mg / ml. 3 The values ​​were measured by dissolving the solution in the following formula 1. However, when the measurement was not performed, "-" is entered.

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Claims

1. Poly(3-hydroxypropionic acid) containing a repeating unit represented by the following chemical formula 1: The poly(3-hydroxypropionic acid) has a vinyl group ratio of 40 mol % or less among its terminal groups. Poly(3-hydroxypropionic acid). 【Chemical 1】

2. The poly(3-hydroxypropionic acid) has a nitrogen content of 100 ppm or less. The poly(3-hydroxypropionic acid) according to claim 1.

3. The poly(3-hydroxypropionic acid) has a YI (yellow index) value of 30 or less. The poly(3-hydroxypropionic acid) according to claim 1.

4. The poly(3-hydroxypropionic acid) has a biocarbon content of 80% by weight or more. The poly(3-hydroxypropionic acid) according to claim 1.

5. The weight average molecular weight of the poly(3-hydroxypropionic acid) is 10,000 or more and 700,000 or less. The poly(3-hydroxypropionic acid) according to claim 1.

6. The number average molecular weight of the poly(3-hydroxypropionic acid) is 7,000 or more and 500,000 or less. The poly(3-hydroxypropionic acid) according to claim 1.

7. the molecular weight distribution (Mw / Mn) of the poly(3-hydroxypropionic acid) is 1.2 to 3.5; The poly(3-hydroxypropionic acid) according to claim 1.

8. polymerizing 3-hydroxypropionic acid at a temperature of 100°C or less to produce poly(3-hydroxypropionic acid); The poly(3-hydroxypropionic acid) has a vinyl group ratio of 40 mol % or less among its terminal groups. Method for producing poly(3-hydroxypropionic acid).

9. The polymerization is a solid-state polymerization carried out at a temperature of 70° C. or less. The method for producing poly(3-hydroxypropionic acid) according to claim 8.

10. The polymerization is carried out in the presence of a catalyst, The catalyst is used in an amount of 0.4 mol% or less relative to the 3-hydroxypropionic acid. The method for producing poly(3-hydroxypropionic acid) according to claim 8.

11. The catalyst is a sulfonic acid catalyst. The method for producing poly(3-hydroxypropionic acid) according to claim 10.

12. The solid-state polymerization is Step 1: solid-state polymerizing 3-hydroxypropionic acid at a temperature of 70°C or less to produce an oligomer; and Step 2: solid-state polymerizing the oligomer at a temperature of 70°C or less to produce the poly(3-hydroxypropionic acid). The method for producing poly(3-hydroxypropionic acid) according to claim 9.

13. Prior to the step of polymerizing 3-hydroxypropionic acid at a temperature of 100°C or less to produce poly(3-hydroxypropionic acid), further comprising the step of drying the 3-hydroxypropionic acid. The method for producing poly(3-hydroxypropionic acid) according to claim 8.

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