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EP-4737501-A1 - BIODEGRADABLE POLYESTER RESIN AND PREPARATION METHOD THEREFOR

EP4737501A1EP 4737501 A1EP4737501 A1EP 4737501A1EP-4737501-A1

Abstract

The present invention relates to a biodegradable polyester resin composition, a preparation method therefor, and a biodegradable polyester film prepared from the composition, wherein the biodegradable polyester resin composition comprises a polymer comprising a residue of a dicarboxylic acid component and a residue of a diol component, and the polymer has a degree of linearity of 0.3 to 0.7, the degree of linearity being represented by equation 1: [Equation 1] Degree of linearity = Log(R g ) / Log(MM), (R g ≤ 30 nm). In equation 1, R g represents the rotational radius of the polymer and is 30 nm or less, and MM represents the molar mass of the polymer.

Inventors

  • IM, Sujin
  • KIM, JEONGSUN
  • YOON, Hoewon
  • KIM, SEONGHUN
  • PAEK, Seunghwan
  • LEE, SUNG WON
  • NAM, JOO HYUN
  • SHIN, HYO JOO

Assignees

  • Kolon Industries, Inc.
  • SK Innovation Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240531

Claims (18)

  1. A biodegradable polyester resin composition comprising a polymer including a residue of a dicarboxylic acid component and a residue of a diol component, wherein the polymer has a degree of linearity of 0.3 to 0.7 as expressed by the following Equation 1: Degree of linearity = Log R g / Log MM , R g ≤ 30 nm in Equation 1, R g is a radius of gyration of the polymer, which is 30 nm or less, and MM is a molar mass of the polymer.
  2. The biodegradable polyester resin composition of claim 1, wherein the polymer has a polydispersity index (PDI) of 1.0 to 2.5.
  3. The biodegradable polyester resin composition of claim 1, wherein the dicarboxylic acid component includes an aromatic dicarboxylic acid having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, the aromatic dicarboxylic acid having 6 to 12 carbon atoms includes terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof, and the aliphatic dicarboxylic acid having 4 to 10 carbon atoms includes adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, cyclic fatty acids, diester derivatives thereof, anhydrides thereof, or mixtures thereof.
  4. The biodegradable polyester resin composition of claim 1, wherein the dicarboxylic acid component includes 30 mol% to 70 mol% of the aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 mol% to 70 mol% of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the dicarboxylic acid component.
  5. The biodegradable polyester resin composition of claim 1, wherein the diol includes an aliphatic diol having 2 to 10 carbon atoms, and the aliphatic diol having 2 to 10 carbon atoms includes 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, cyclic aliphatic diols, or mixtures thereof.
  6. The biodegradable polyester resin composition of claim 1, wherein a molar ratio of the dicarboxylic acid component and the diol component is 1.0:0.8 to 1.0:1.2.
  7. The biodegradable polyester resin composition of claim 1, wherein the biodegradable polyester resin composition has a melt flow index (MI) of 10 g/10 min or less as measured at 190 °C under a load of 2.16 kg according to the ASTM D1238 standard.
  8. A method of preparing a biodegradable polyester resin composition, comprising: a first step of preparing a raw material mixture including an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol; a second step of reacting the raw material mixture to prepare an oligomer; a third step of subjecting the oligomer to polycondensation to prepare a prepolymer; and a fourth step of adding a chain extender to the prepolymer to prepare a polymer, thereby obtaining a biodegradable polyester resin composition, wherein a moisture content of the raw material mixture in the first step is 3000 ppm or less, and the polymer prepared in the fourth step has a degree of linearity of 0.3 to 0.7, as expressed by the following Equation 1: Degree of linearity = Log R g / Log MM , R g ≤ 30 nm in Equation 1, R g is a radius of gyration of the polymer, which is 30 nm or less, and MM is a molar mass of the polymer.
  9. The method of claim 8, wherein the polymer has a polydispersity index (PDI) of 1.0 to 2.5.
  10. The method of claim 8, wherein a particle size dispersion index (SPAN) of the aromatic dicarboxylic acid is 5.0 or less.
  11. The method of claim 8, wherein a end-group conversion rate of the oligomer is expressed by the following Equation 2, and the end-group conversion rate is 90% to 100%: End - group conversion rate % = SV − AV SV × 100 in Equation 2, AV is an acid value expressed by the following Equation 2-1, and SV is a saponification value expressed by the following Equation 2-2: Acid value AV = 0.1 × A × P W in Equation 2-1, A is a titration volume (ml) of a 0.1 N sodium hydroxide solution, P is a titer of the 0.1 N sodium hydroxide solution, and W is a mass of the oligomer; and Saponification value SV = 0.5 × C − B × Q W ′ in Equation 2-2, B is a titration volume (ml) of a 0.5 N hydrochloric acid solution (HCl), C is a titration volume (ml) of a blank solution, Q is a titer of the 0.5 N hydrochloric acid solution, and W' is a mass of the oligomer.
  12. The method of claim 8, wherein the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or combinations thereof, and the aliphatic dicarboxylic acid is adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, cyclic fatty acids, diester derivatives thereof, anhydrides thereof, or combinations thereof.
  13. The method of claim 8, wherein the aromatic dicarboxylic acid is included in an amount of 20 mol% to 50 mol% and the aliphatic dicarboxylic acid is included in an amount of 20 mol% to 50 mol%, based on the total number of moles of the raw material mixture.
  14. The method of claim 8, wherein the aliphatic diol is 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, cyclic aliphatic diols, or combinations thereof.
  15. The method of claim 8, wherein the aliphatic diol is included in an amount of 30 mol% to 60 mol% based on the total number of moles of the raw material mixture.
  16. The method of claim 8, wherein a molar ratio of the aromatic dicarboxylic acid and aliphatic dicarboxylic acid and the aliphatic diol is 1.0:0.8 to 1.0:1.2.
  17. A biodegradable polyester film obtained by melt-extruding the biodegradable polyester resin composition of any one of claims 1 to 7 using a blown film extruder.
  18. A biodegradable polyester film obtained by melt-extruding a biodegradable polyester resin composition prepared by the preparation method of any one of claims 8 to 16 using a blown film extruder.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of Korean Patent Application No. 10-2023-0085267, filed on June 30, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. BACKGROUND 1. Field The present disclosure relates to a biodegradable polyester resin and a method of preparing the same. 2. Description of Related Art Polyester resin refers to a polymer resin that has an ester (RO-C(=O)-R') functional group in the main chain, and is used in various applications across multiple industries, such as packaging, displays, and insulating materials. Recently, considering environmental protection issues, research on biodegradable polyester compositions is continuing. In general, the biodegradable polyester compositions are prepared using an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, and an aliphatic diol as main raw materials and branching agents, catalysts, and heat stabilizers as auxiliary raw materials. Specifically, a biodegradable polyester resin is prepared by subjecting the main raw materials to an esterification reaction and a polycondensation reaction in the presence of the auxiliary raw materials, and in some cases, a chain extension reaction is also performed after the polycondensation reaction to enhance the mechanical properties of the biodegradable polyester resin. In addition, the physical properties of the final biodegradable polyester resin may vary depending on the properties of the raw material mixture used in the preparation of biodegradable polyester. SUMMARY According to one embodiment, a biodegradable polyester resin composition having excellent processability and mechanical properties is provided. According to another embodiment, a method of preparing the biodegradable polyester resin composition is provided, which can improve the productivity and processability of the biodegradable polyester resin composition. [Technical Solution] A biodegradable polyester resin composition according to one embodiment includes a polymer including a residue of a dicarboxylic acid component and a residue of a diol component, wherein the polymer has a degree of linearity of 0.3 to 0.7, as expressed by the following Equation 1: Degreeoflinearity=LogRg/LogMM,Rg≤30nm in Equation 1, Rg is a radius of gyration of the polymer, which is 30 nm or less, andMM is a molar mass of the polymer. The polymer has a polydispersity index (PDI) of 1.0 to 2.5. The dicarboxylic acid component may include an aromatic dicarboxylic acid having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, wherein the aromatic dicarboxylic acid having 6 to 12 carbon atoms may include terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof, and the aliphatic dicarboxylic acid having 4 to 10 carbon atoms may include adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, cyclic fatty acids, diester derivatives thereof, anhydrides thereof, or mixtures thereof. The dicarboxylic acid component may include 30 mol% to 70 mol% of the aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 mol% to 70 mol% of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the dicarboxylic acid component. The diol may include an aliphatic diol having 2 to 10 carbon atoms, and the aliphatic diol having 2 to 10 carbon atoms may include 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, cyclic aliphatic diols, or mixtures thereof. A molar ratio of the dicarboxylic acid component and the diol component is 1.0:0.8 to 1.0:1.2. The biodegradable polyester resin composition has a melt flow index (MI) of 10 g/10 min or less as measured at 190°C under a load of 2.16 kg according to the ASTM D1238 standard. A method of preparing a biodegradable polyester resin composition according to another embodiment includes a first step of preparing a raw material mixture including an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol; a second step of reacting the raw material mixture to prepare an oligomer; a third step of subjecting the oligomer to polycondensation to prepare a prepolymer; and a fourth step of adding a chain extender to the prepolymer to prepare a polymer, thereby obtaining a biodegradable polyester resin composition, wherein a moisture content of the raw material mixture in the first step is 3000 ppm or less, and the polymer prepared in the fourth step has a degree of linearity of 0.3 to 0.7, as expressed by Equation 1. The polymer has a PDI of 1.0 to 2.5. A particle size dispersion index (SPAN) of the aromatic dicarboxylic acid is 5.0 or less. A end-group conversion rate of the oligomer is expressed by the following Equation 2, and the