JP4766893B2 - Polymer and production method thereof - Google Patents

Description

  The present invention relates to a polymer and a method for producing the same, and more particularly to a polymer having a structural unit containing α-hydroxycarboxylic acid / mandelic acid such as lactic acid, and a method for producing the same.

  In recent years, from the viewpoint of protecting the natural environment, biodegradable polymers that can be decomposed in the natural environment and molded articles thereof have been demanded, and research on natural degradable resins such as aliphatic polyesters has been actively conducted. In particular, since polylactic acid has a sufficiently high melting point of 130 to 180 ° C. and excellent transparency, it is used for applications such as packaging materials and molded articles that make use of transparency. In addition, lactic acid, which is a raw material for polylactic acid, is obtained from renewable resources such as plants, and is highly expected from the point of not using depleted resources such as petroleum.

  Polylactic acid is a crystalline thermoplastic polymer, but the crystallization is very slow. For example, a molded product by injection molding or the like has excellent rigidity, but has low heat resistance, or both heat resistance and impact resistance. For example, hot water or a microwave oven cannot be used in a packaging container, and its application is limited. Further, storage parts such as a CD case and a cassette case are subject to thermal deformation at high temperatures and cannot be used in automobiles.

  In order to impart heat resistance, it has been studied to crystallize polylactic acid. A method of adding a nucleating agent is known as a method for promoting crystallization. Examples of adding such an additive to a biodegradable polymer include Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5.

  In Patent Document 1, as a material for a plastic container, a biodegradable plastic such as poly-3-hydroxybutyrate / poly-3-hydroxyvalerate copolymer, polycaprolactone, or polylactic acid has an average particle size of 20 μm. It is disclosed that the following calcium carbonate and talc are mixed at a weight ratio of 10 to 40%. However, this technique promotes the decomposition of the biodegradable plastic after disposal by adding a large amount of an inorganic filler, and does not improve the heat resistance by crystallizing the polymer.

  Patent Document 2 describes that the properties of hardness, strength, and temperature resistance are changed by adding fillers of inorganic compounds such as silica and kaolinite to polylactide thermoplastics. , 5% by weight of calcium lactate as a nucleating agent was blended with a L, DL-lactide copolymer for 5 minutes with a heating roll at a temperature of 170 ° C., and the sheet was rigid, strong and cloudy, and had a crystallinity. It is described that increased.

  Patent Document 3 describes lactate and benzoate as nucleating agents. In this example, 1% calcium lactate is blended with a polylactide copolymer and maintained at about 85 ° C. with a residence time of 2 minutes. However, there is an example in which the mold was further annealed at about 110 to 135 ° C. because of insufficient crystallization.

  In Patent Document 4, polyglycolic acid and its derivatives are added to poly L-lactide as a nucleating agent to increase the crystallization speed, thereby shortening the injection molding cycle time and having excellent mechanical properties. It is described. As an example of injection molding, the crystallization temperature without a nucleating agent is 22.6% when the cooling time is 60 seconds, and 45.5% when the nucleating agent is added. However, according to Patent Document 5, when an injection molding was attempted without actually adding a nucleating agent to the lactic acid-based polymer, as described in Patent Document 4, the mold temperature was higher than the glass transition temperature. It is described that it could not be molded.

  On the other hand, Patent Document 5 actually tried injection molding using ordinary talc, silica, calcium lactate, etc. as a nucleating agent for a lactic acid-based polymer, but because the crystallization rate was slow and the molded product was brittle, A molded product that can withstand practical use cannot be obtained. Therefore, even if such lactic acid-based polymers are used for general injection molding, blow molding, and compression molding using ordinary talc, silica, etc., the crystallization rate is low, and the resulting molded product has practical heat resistance. It is described that there is a limitation in application because it is low at 100 ° C. or lower and impact resistance is not strong.

  However, when polylactic acid is crystallized, the transparency is lost. The glass transition temperature of polylactic acid is about 60 ° C., and it was necessary to increase the glass transition temperature of the polymer in order to increase the heat resistance while maintaining transparency in the glass (amorphous) state.

The present inventor has focused on a natural product-derived mandelic acid having a structure similar to that of lactic acid and having an aromatic ring, and has attempted to polymerize it to form a polymer. Dimer formation occurred, and the chain molecule was limited to an oligomer having a degree of polymerization of about 10, and a polymer could not be obtained.
Japanese Patent Application Laid-Open No. 5-70696

  Japanese translation of PCT publication No. 4-5044731 (WO 90/01521)

  JP-T 6-504799

  JP-A-4-220456

  JP-A-8-193165

  The object of the present invention is to provide a polymer (aliphatic aromatic polyester) having a glass transition temperature higher than that of polylactic acid and a method for producing the same in order to solve the above-mentioned problems of the prior art and to impart heat resistance. There is.

  As a result of intensive studies, the inventors of the present application have found that an aliphatic aromatic polyester having an aromatic substituent can achieve the above object, and have completed the present invention.

  That is, the first polymer according to the present invention is obtained by ring-opening polymerization of a cyclic diester represented by the following general formula (Chemical Formula 1) (aliphatic aromatic polyester) It is.

Note that one asymmetrical carbon atom is generated when R = H and two asymmetric carbon atoms are generated when R = CH ₃ , but the steric configuration can be a raw material for the polymer of the present invention in any case. Examples of the obtained polymer include polymers represented by the following general formula (Formula 2).

  However, when mandelic acid is M and lactic acid (or glycolic acid) is L, they are not always connected in the order of “MLML”, and M or L may be connected.

  Moreover, the manufacturing method of the 1st polymer which concerns on this invention is a manufacturing method of the polymer characterized by ring-opening-polymerizing the cyclic diester represented by General formula (Formula 1).

  The second polymer according to the present invention is a polymer obtained by ring-opening copolycondensation of a cyclic diester represented by the general formula (Chemical Formula 1) and lactides.

  The second polymer production method according to the present invention is characterized by ring-opening copolymerization of a cyclic diester represented by the general formula (Formula 1) and a lactide such as glycolide or L-lactide. It is a manufacturing method of a polymer.

  The polymer according to the present invention has a higher content ratio of mandelic acid than a polymer produced by a method that does not rely on ring-opening polymerization, and thus has an effect that the glass transition temperature can be increased as compared with polylactic acid.

Hereinafter, embodiments of the present invention will be described in detail.
In the present invention, a method for synthesizing the cyclic diester represented by the formula (Formula 3) will be described. First, in a trimethylamine / diethyl ether solution, bromoacetyl chloride (BrCH ₂ COCl) is added to L-mandelic acid for esterification to obtain L-2- (Bromoacetoxy) -2-phenethylenic acid (L-BAP). . Thereafter, in an acetone solution, calcium carbonate is added to L-BAP to carry out a cyclization reaction to obtain L-3-Phenyl-1,4-dioxane-2,5-dione (L-PDD) which is a cyclic diester. It was.

In the present invention, a method for synthesizing the cyclic diester represented by the formula (Formula 4) will be described. First, in a trimethylamine / diethyl ether solution, esterification was performed by adding 2-bromopropionyl chloride (CH ₃ (Br) CHCOCl) (BPC) to L-mandelic acid, and L-2- (2-Bromopropionyloxy)- 2-Phenylethanoic acid (L-BPP) is obtained. Thereafter, in an acetone solution, calcium carbonate is added to L-BPP to carry out a cyclization reaction, and 3- (S) -Methyl- (L) -6-phenyl-1,4-dioxane-2, which is a cyclic diester, 5-dione (L-MPDD) was obtained.

  In the present invention, a method for polymerizing an aliphatic aromatic polyester that is a polymer represented by the formula (Formula 5) will be described. An L-PDD, which is a cyclic diester represented by the above formula (Chemical Formula 3), is added with a polymerization catalyst such as tin octylate, and heated under reduced pressure to perform ring-opening polymerization, so that it is a polyaromatic polyester. (L-mandelic acid-co-glycolic acid) (PLMAGA) was obtained.

  In the present invention, a method for polymerizing an aliphatic aromatic polyester that is a polymer represented by the formula (Formula 6) will be described. An L-MPDD, which is a cyclic diester represented by the above formula (Chemical Formula 4), is added with a polymerization catalyst such as tin octylate, and heated under reduced pressure to perform ring-opening polymerization, so that an aliphatic aromatic polyester is poly. (L-mandelic acid-co-lactic acid) (PLMALA) was obtained.

  In the present invention, the copolymerization of L-PDD represented by the formula (Chemical Formula 3) and lactide will be described. Poly (L-mandelic) which is an aliphatic aromatic polyester containing more glycolic acid units than the polyester represented by the formula (Chemical Formula 5) by adding a polymerization catalyst to L-PDD and glycolide and heating and ring-opening polymerization. acid-co-glycic acid) (PLMAGA) was obtained. Similarly, by adding a polymerization catalyst to L-PDD and lactide and heating under reduced pressure to perform ring-opening polymerization, an aliphatic aromatic polyester Poly (L-mandelic acid-co-glycylic acid-co-lactic) is obtained. acid) (PLMAGALA).

  In the present invention, the copolymerization of L-MPDD represented by the formula (Formula 4) and lactide will be described. A polymerization catalyst was further added to L-MPDD and lactide, and the mixture was heated under reduced pressure to undergo ring-opening polymerization to obtain an aliphatic aromatic polyester, Poly (L-mandelic acid-co-lactide acid) (PLMALA). .

  The polymerization catalyst used for the polymerization reaction described above is not limited to tin octylate, and various known lactic acid polymerization catalysts can be used. For example, tin-based compounds such as tin lactate, tin tartrate, dicaprylate, dilaurate, dipalmitate, tin distearate, tin dioleate, tin α-naphthoate, tin β-naphthoate, powder tin, oxidation Tin, zinc dust, zinc halide, zinc oxide, organic zinc compounds, titanium compounds such as tetrapropyl titanate, zirconium compounds such as zirconium isopropoxide, antimony compounds such as antimony trioxide, bismuth oxide (III) And bismuth compounds such as aluminum oxide and aluminum compounds such as aluminum isopropoxide. Among these, a catalyst made of tin or a tin compound is particularly preferable from the viewpoint of activity.

  Moreover, as a lactide used for this invention, you may use any lactide of glycolide, L-lactide, D-lactide, DL-lactide, meso-lactide, or these mixtures.

In the present invention and the following examples, ¹ H NMR spectra were measured using a Varian Gemini-200 measuring apparatus (200 MHz), using deuterated chloroform (CDCl ₃ ) as a solvent and tetramethylsilane as an internal standard. A chemical shift was determined and analyzed. DSC measurement was performed using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation, and 3 mg of a sample sample was measured at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
( Reference Example 1)
L-mandelic acid (3.347 g) was placed in a three-necked eggplant flask, and the reaction system was heated to a vacuum to melt and dry L-mandelic acid, followed by substitution with nitrogen. Thereafter, the mixture was allowed to cool to room temperature, dissolved in 80 ml of diethyl ether, immersed in an ice bath and cooled for 1 hour. When the reaction system is stabilized at 5 ° C. or less, 4.501 g of bromoacetyl chloride (BrCH ₂ COCl) is added, and further, 3.339 g / 20 ml of trimethylamine / diethyl ether solution is added while cooling so that the temperature of the reaction system does not become 5 ° C. or less. The solution was dropped at a rate of 1 drop / 3 seconds. After completion of dropping, the ice bath was removed and stirring was continued for 12 hours. Distilled water was added to the resulting solution to stop the reaction, and the reaction solution was transferred to a separatory funnel and washed ten times with distilled water. Magnesium sulfate was added to this solution and allowed to stand for 15 hours with stirring. Magnesium sulfate was filtered off, concentrated on a rotary evaporator, and dried in vacuo at room temperature to give 2- (bromoacetoxy) -2-phenethylenic acid (L-BAP), which was a tan and oily liquid. When the obtained L-BAP was analyzed by ¹ H NMR, δ / ppm: 3.96 (s, 2H, CH ₂ ), 5.98 (s, 1H, CH), 7.42 (m, 5H, C ₆ H ₅ ).

Next, 0.2627 g of sodium carbonate was added to the eggplant flask, 300 ml of acetone was added, and the mixture was heated to 60 ° C. to reflux the acetone. Next, an L-BAP / acetone 1.3654 g / 200 ml solution was added dropwise over 6 hours with stirring, and the reaction was continued for another 30 minutes after the completion of the addition. Insoluble sodium bromide was removed by filtration, acetone was concentrated with a rotary evaporator, and reprecipitation was performed with 2-propanol to obtain white powder of L-PDD. When the obtained L-PDD was analyzed by ¹ H NMR, δ / ppm: 4.78 (q, 2H, C H ₂ ), 6.07 (s, 1H, C H ), 7.47 (m, 5H, C ₆ H ₅ ). Further, when the obtained L-PDD was measured by DSC, the melting point was 131.4 ° C. The yield was 90% and the yield after recrystallization was 14%.

( Reference Example 2)
Put 8.994 g of thionyl chloride (SOCl ₂ ) in a _two- necked eggplant flask and stir it in an ice bath, stirring 11.595 g of 2- (S) -bromopropionic acid (BPA) at a rate of 1 drop / 3 seconds. It was dripped at. After completion of dropping, the mixture was further stirred for 2 hours to synthesize 2- (S) -bromopropionyl chloride (BPC). The synthesized crude BPC was directly used for the next reaction.

Next, 3.347 g of L-mandelic acid was placed in a three-necked eggplant flask, and the reaction system was heated under vacuum to melt and dry L-mandelic acid, followed by substitution with nitrogen. Thereafter, the mixture was allowed to cool to room temperature, dissolved by adding 80 ml of diethyl ether, immersed in an ice bath and cooled for 1 hour. When the reaction system was stabilized at 5 ° C. or lower, 2.36 g of the previously synthesized BPC was added, and 3.339 g / 20 ml of a trimethylamine / diethyl ether solution was further added dropwise at a rate of 1 drop / 3 seconds. At this time, it was cooled so that the temperature of the reaction system did not rise above 5 ° C. After completion of dropping, the ice bath was removed and stirring was continued for 12 hours. Distilled water was added to the resulting solution to stop the reaction, and the reaction solution was transferred to a separatory funnel and washed ten times with distilled water. Magnesium sulfate was added to this solution and left overnight with stirring. Magnesium sulfate is filtered off, concentrated on a rotary evaporator, and vacuum-dried at room temperature to give 2- (S) -2-bromopropionyloxy-2-phenylethaneic acid (L-BPP) which is a milky white oily liquid. It was. When the obtained L-BPP was analyzed by ¹ H NMR, δ / ppm: 1.88 (d, 3H, C H ₃ ), 14.50 (q, 1 H, C H ), 5.97 (s, 1H, C H ), 7.43 (m, 5H, C ₆ H ₅ ).

Next, 0.2627 g of sodium carbonate was added to the eggplant flask, 300 ml of acetone was added, and the mixture was heated to 60 ° C. to reflux the acetone. Next, the L-BPP / acetone 1.3654 g / 200 ml solution was added dropwise over 6 hours with stirring, and the reaction was continued for another 30 minutes after completion of the addition. Insoluble sodium bromide was filtered off, acetone was concentrated with a rotary evaporator, and reprecipitation was performed with 2-propanol to obtain L-MPDD as a white powder. When the obtained L-MPDD was analyzed by ¹ H NMR, δ / ppm: 1.63 (d, 3H, C H ₃ ), 5.18 (q, 1 H, C H ), 5.93 (s, 1H, C H ), 7.44 (m, 5H, C ₆ H ₅ ). Further, when the obtained L-MPDD was measured by DSC, the melting point was 132.2 ° C. The yield was 99.7% and the yield after recrystallization was 30%. [Α] ²⁰ _D = + 109.8 ° (in acetone, 0.41 g / dl), as a result of elemental analysis, Found: H = 5.00, C = 64.31; Calcd: H = 4.85, C = 64.08.

( Reference Example 3-1)
96 mg of L-PDD prepared in Reference Example 1 was put in a test tube, dried under reduced pressure and purged with nitrogen, and then 0.1 mol% tin (II) octylate solution diluted in toluene solution was added to L-PDD. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 1 hour. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain a white powdery PLMAGA. When the obtained PMMAGA was analyzed by ¹ H NMR, δ / ppm: 4.72 (q, 2H, CH ₂ ), 6.09 (s, 1H, CH), 7.35 (m, 5H, C ₆ It was H _5). Further, when the obtained PLMAGA was measured by DSC, the glass transition temperature was 79.4 ° C.

( Reference Example 3-2)
L-PDD (300 mg) was placed in a test tube, dried under reduced pressure and purged with nitrogen, and then 0.2 mol% of tin (II) octylate solution diluted in toluene solution was added to L-PDD. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 6 hours. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain PLMAGA as a white powder (yield 255 mg). As a result of GPC analysis of the obtained PLMAGA, the molecular weight was Mn = 6800, and the degree of dispersion was Mw / Mn = 1.5.

( Reference Example 4-1)
As in Reference Example 3, 103 mg of L-MPDD prepared in Reference Example 2 was placed in a test tube, dried under reduced pressure and purged with nitrogen, and then 0.1 mol% tin octylate (diluted in a toluene solution with respect to L-MPDD) ( II) The solution was added. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 1 hour. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain a yellow powdery PMMALA. When the obtained PMMALA was analyzed by ¹ H NMR, δ / ppm: 1.63 (d, 3H, CH ₃ ), 5.16 (q, 1H, CH), 5.96 (s, 1H, CH) 7.38 (m, 5H, C ₆ H ₅ ). Moreover, when the obtained PMMALA was measured by DSC, the glass transition temperature was 80.9 degreeC.

( Reference Example 4-2)
300 mg of L-MPDD prepared in Reference Example 2 was put in a test tube, dried under reduced pressure and purged with nitrogen, and then 0.2 mol% of tin (II) octylate solution diluted in toluene solution was added to L-MPDD. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 180 ° C. for 3 hours. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain PMMALA as a yellow powder (yield 223 mg). As a result of GPC analysis of the obtained PLMAGA, the molecular weight was Mn = 3840 and the degree of dispersion was Mw / Mn = 2.3.

( Reference Example 4-3)
Under the same conditions as in Reference Example 4-2, when the polymerization time was 6 hours, PLMALA was obtained in a yield of 287 mg. As a result of GPC analysis of the obtained PLMAGA, the molecular weight Mn = 10400, the degree of dispersion Mw / Mn = 2.7, and the glass transition temperature was 75 ° C.

(Example 5-1)
In the same manner as in Example 3, L-PDD and L-lactide prepared in Example 1 were placed in a test tube at a feed ratio of 5:95, dried under reduced pressure, and purged with nitrogen. After melt-mixing this at 150 ° C., a 0.1 mol% tin (II) octylate solution was added to the total amount of monomers diluted in the toluene solution. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 1 hour. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain an L-mandelic acid-glycolic acid-L-lactic acid copolymer (PLMAGALA). When the obtained PLMAGALA was analyzed by ¹ H NMR, δ / ppm: 1.58 (d, 3H, C H ₃ ), 4.72 (q, 2H, C H ₂ ), 5.16 (q, 1H) , C H ), 6.01 (s, 1H, C H ), 7.41 (m, 5H, C ₆ H ₅ ). Moreover, when the obtained PLMAGALA was measured by DSC, the glass transition temperature was 73.4 degreeC.

(Example 5-2)
L-PDD 150 mg (0.785 mmol) and L-lactide 150 mg (114 mmol) were placed in a test tube, and 0.002 mol% tin (II) octylate toluene solution was added thereto. This was dried under reduced pressure for 3 hours and then purged with nitrogen. Furthermore, it heated at 150 degreeC for 3 hours, the obtained brown solid was melt | dissolved in chloroform, and it reprecipitated with methanol. The reprecipitation solution was centrifuged for 1 hour, and the supernatant was removed by decantation. The precipitate was dried under reduced pressure to obtain PLMAGALA (258 mg) as a white solid.

(Example 6-1)
In the same manner as in Example 3, L-MPDD and L-lactide prepared in Example 2 were placed in a test tube at a feed ratio of 5:95, dried under reduced pressure, and purged with nitrogen. After melt-mixing this at 150 ° C., a 0.1 mol% tin (II) octylate solution was added to the total amount of monomers diluted in the toluene solution. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 1 hour. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain an L-mandelic acid-lactic acid-L-lactic acid copolymer (PLMALALA). The obtained PMMALALA was analyzed by ¹ H NMR. As a result, δ / ppm: 1.58 (d, 3H, C H ₃ ), 5.16 (q, 1 H, C H ), 6.01 (s, 1 H, C H ), 7.41 (m, 5H, C ₆ H ₅ ). Further, when the obtained PLMALALA was measured by DSC, the glass transition temperature was 75.1 ° C.

(Example 6-2)
L-MPDD 121 mg (0.59 mmol) and L-lactide 85 mg (0.6 mmol) were placed in a test tube, and a 0.002 mol% tin (II) octylate toluene solution was added. This was dried under reduced pressure for 3 hours and heated at 175 ° C. for 6 hours. The obtained brown solid was dissolved in chloroform and reprecipitated with methanol. The reprecipitation solution was centrifuged for 1 hour, the supernatant was removed by decantation, and the precipitate was dried under reduced pressure to obtain PLMALALA (0.15 g) as a white solid.

(Example 7)
L-PDD 150 mg (0.781 mmol) and glycolide 150 mg (1.34 mmol) are put in a test tube, 1/500 mol of tin octylate (toluene solution) is added to them, and a vacuum pump is used for 3 hours at room temperature. It was dried under reduced pressure. Then, it superposed | polymerized by heating at 150 degreeC for 3 hours. The white solid obtained by the polymerization was dissolved in chloroform and poured into a large excess of methanol for reprecipitation, and then the supernatant was removed by decantation. The obtained solid product was vacuum-dried to obtain 288 mg of a white solid copolymer. When ¹ H NMR was measured, a spectrum showing a signal at the same chemical shift position as that of PMMAGA obtained in Example 3-1 was obtained. That is, the copolymer is a polymer having units of mandelic acid and glycolic acid, and the molar composition of mandelic acid and glycolic acid units was 1: 4.4 from the integral ratio of each signal. As for its molecular weight, the number average molecular weight was 53,000 from GPC analysis.

(Comparative example)
L-lactide was put in a test tube, dried under reduced pressure and purged with nitrogen, and then 0.1 mol% tin (II) octylate solution diluted in a toluene solution was added to L-lactide. After stirring for 5 minutes under normal pressure, the pressure was reduced to remove toluene, and polymerization was carried out at 150 ° C. for 1 hour. The product was dissolved in chloroform and reprecipitated in 10 volumes of diethyl ether. The solution was removed by decantation, and the precipitate was dried under reduced pressure at 80 ° C. for 12 hours to obtain white powdery poly-L-lactic acid (PLLA). When the obtained PLLA was analyzed by ¹ H NMR, δ / ppm: 1.63 (d, 3H, C H ₃ ), 5.16 (q, 1 H, C H ), 5.96 (s, 1 H, C H ), 7.38 (m, 5H, C ₆ H ₅ ). When the obtained PLLA was subjected to DSC measurement, the glass transition temperature was 60.6 ° C.

  The present invention can be suitably used for packaging materials, coating materials, molded article materials, and the like.

Claims (3)

The following general formula (Formula 1)
A polymer obtained by ring-opening copolycondensation of a cyclic diester represented by formula (II) with glycolide, L-lactide, D-lactide, DL-lactide, meso-lactide, or a mixture thereof.   The polymer according to claim 1, which has a glass transition temperature higher than that of polylactic acid. The following general formula (Formula 1)
The ring-opening copolycondensation of the cyclic diester represented by the following formula with glycolide, L-lactide, D-lactide, DL-lactide, meso-lactide or a mixture thereof: Manufacturing method of coalescence.