Biodegradable polyester resin and method for producing the same

Abstract

The present invention relates to a biodegradable polyester resin and a method for producing the same. The present invention provides a biodegradable polyester resin composition comprising polyester resin particles containing residues of dicarboxylic acid and diol components; a titanium (Ti)-based catalyst; and a phosphorus (P)-based heat stabilizer, wherein the composition contains 10 mass% or less of polyester resin particles with a size of 20 nm or more as measured by DLS, based on the total amount (100 mass%) of the biodegradable polyester resin composition, and the titanium (Ti)-based catalyst and the phosphorus (P)-based heat stabilizer satisfy the following mathematical formula 1. [Mathematical formula 1] 1 < [A] / [B] < 20 In the above mathematical formula 1, [A] is the weight (ppm) of titanium (Ti) contained in the titanium (Ti)-based catalyst, [B] is the weight (ppm) of phosphorus (P) contained in the phosphorus (P)-based heat stabilizer.

Description

Technical Field

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[0001] The present disclosure relates to a biodegradable polyester resin and a method for producing the same.

Background Art

[0002] A polyester resin means a polymer resin having an ester (RO-C(=O)-R’) functional group in its main chain and is used in various applications such as for packaging, displays, insulating materials, etc. in various industrial fields. Recently, considering environmental protection issues, research on biodegradable polyester compositions has been ongoing.

[0003] Generally, an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, and an aliphatic diol are used as main raw materials, and a branching agent, a titanium (Ti)-based catalyst, and a phosphorus (P)-based heat stabilizer are used as auxiliary raw materials to produce a biodegradable polyester composition.

[0004] Specifically, in the presence of the auxiliary raw materials, the main raw materials are subjected to an esterification reaction and a polycondensation reaction to produce a biodegradable polyester composition. In some cases, after the polycondensation reaction, a chain extension reaction may be carried out to enhance the mechanical properties of the biodegradable polyester composition.

[0005] However, due to the influence of the branching agent and the chain extension reaction, if macromolecules or aggregates are present in the final biodegradable polyester composition, the cooling crystallization temperature becomes high and the tear strength in the longitudinal direction becomes weak.

[0006] On the other hand, the physical properties of the final biodegradable polyester resin composition also change depending on the content ratio of the auxiliary raw materials.

Summary of the Invention

Problems to be Solved by the Invention

[0007] One embodiment aims to produce a biodegradable polyester composition in which macromolecules or aggregates are minimized and various physical properties are improved in a well-balanced manner. [Means for solving the problem]

[0008] In one embodiment, a polyester resin composition is provided that contains a polyester resin comprising a dicarboxylic acid component residue and a diol component residue; titanium (Ti); and phosphorus (P), wherein the composition contains 10 mass% or less of polyester resin particles with a size of 20 nm or larger as measured by DLS, relative to the total amount (100 mass%) of the biodegradable polyester resin composition, and the content ratio of titanium (Ti) and phosphorus (P) contained in the biodegradable polyester resin composition satisfies the following mathematical formula 1. [Mathematical formula 1] 1 < [A] / [B] < 20 In the above mathematical formula 1, [A] is the weight (ppm) of titanium (Ti), and [B] is the weight (ppm) of phosphorus (P). [Effects of the Invention]

[0009] A polyester resin according to one embodiment can minimize macromolecules or aggregates and improve various physical properties in a balanced manner. [Modes for carrying out the invention]

[0010] The advantages and features of the technologies described below, and the methods for achieving them, will become clearer with reference to the embodiments described in detail later, along with the accompanying drawings. However, the forms that can be realized are not limited to the embodiments disclosed below. Unless otherwise defined, all terms used herein (including technical and scientific terms) should be used in a sense that can be commonly understood by a person of ordinary skill in the art. Furthermore, terms defined in commonly used dictionaries should not be interpreted ideally or excessively unless explicitly defined otherwise.

[0011] Throughout this specification, when a part of a section "includes" a component, this means, unless otherwise specified, that it may include other components rather than excluding them. Furthermore, singular nouns also include plural nouns unless otherwise specified in the text.

[0012] In this specification, "residue (of a component, such as a dicarboxylic acid or diol)" means a predetermined portion or unit derived from a specific component (compound) that is included in the result of a chemical reaction when that specific component participates in the chemical reaction. Specifically, each "residue" of the dicarboxylic acid component or "residue" of the diol component means a portion derived from the dicarboxylic acid component or a portion derived from the diol component in a polyester copolymer formed by an esterification reaction and / or a condensation polymerization reaction.

[0013] Based on the definitions described above, embodiments of the present invention will be described in detail. However, these are presented as examples only and do not limit the present invention, which is defined only by the scope of the claims described later.

[0014] (Biodegradable polyester resin) One embodiment involves producing a biodegradable polyester composition in which macromolecules or aggregates are minimized and various physical properties are improved in a well-balanced manner.

[0015] Generally, biodegradable polyester compositions are manufactured using aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic diols as the main raw materials, with branching agents, titanium (Ti)-based catalysts, and phosphorus (P)-based heat stabilizers as secondary raw materials.

[0016] Specifically, a biodegradable polyester composition is produced by carrying out esterification and polycondensation reactions of the main raw material in the presence of the auxiliary raw material, and in some cases, a chain extension reaction may be carried out after the polycondensation reaction to enhance the mechanical properties of the biodegradable polyester composition.

[0017] (1) In biodegradable polyester resins, if macromolecules or aggregates are present in the final biodegradable polyester composition due to the influence of the branching agent and the chain extension reaction, the cooling crystallization temperature increases and the tear strength in the longitudinal direction weakens.

[0018] In this regard, one embodiment provides a biodegradable polyester resin in which the content of macromolecules or aggregates is limited to a specific range.

[0019] Here, "tear strength" refers to the degree of resistance of a polymer film to tearing. Generally, when the density of the polymer resin composition is low, the molecular weight distribution is narrow, and the molecular arrangement in the mechanical and transverse directions is balanced, the tear strength of a polymer film produced from such a polymer resin composition increases.

[0020] In contrast, when macromolecules or aggregates are present in a polymer resin composition, not only does the molecular weight distribution increase, but the cooling and crystallization temperature becomes non-uniform. During blown film processing, this non-uniform cooling makes it difficult for the molecular arrangement to balance, resulting in a weakened tear strength in the longitudinal direction (MD).

[0021] If a polymer resin composition has low tear strength, the resulting film will be prone to tearing. In particular, when a polymer resin composition with low tear strength is used as an agricultural mulch film, tearing of the polymer film can cause damage to crop cultivation.

[0022] For reference, GPC (Gel permeation chromatography), a widely known method for measuring molecular weight distribution, measures relative molecular weight, making it difficult to quantify macromolecules or aggregates within a polymer resin composition. In contrast, DLS (Dynamic Light Scattering) can measure the hydrodynamic diameter of polymers dispersed within a polymer resin composition, thereby enabling the quantification of macromolecules or aggregates.

[0023] In this regard, in one embodiment, DLS is used to determine the size of macromolecules or aggregates.

[0024] Specifically, the inventors have found that when the content of the polyester resin having a size of 20 nm or more measured by DLS exceeds 10 mass% with respect to the total amount (100 mass%) of the biodegradable polyester resin composition, the tear strength is significantly weakened.

[0025] Therefore, in one embodiment, it is controlled such that the content of the polyester resin having a size of 20 nm or more measured by DLS is 10 mass% or less with respect to the total amount (100 mass%) of the biodegradable polyester resin composition.

[0026] (2) On the other hand, in the biodegradable polyester resin composition, the physical properties of the final biodegradable polyester resin composition also vary depending on the content ratio of the auxiliary raw materials.

[0027] In this regard, in one embodiment, a biodegradable polyester resin is provided in which the content ratio of the titanium (Ti)-based catalyst and the phosphorus (P)-based heat stabilizer is limited to a specific range.

[0028] Specifically, the inventors have found that when the titanium (Ti)-based catalyst and the phosphorus (P)-based heat stabilizer in the biodegradable polyester resin composition do not satisfy the following Mathematical Formula 1, at least one of the physical properties of the polymer film deteriorates.

[0029] Therefore, in one embodiment, in the biodegradable polyester resin composition, the titanium (Ti)-based catalyst and the phosphorus (P)-based heat stabilizer are controlled to satisfy the following Mathematical Formula 1.

[0030] [Mathematical Formula 1] 1 < [A] / [B] < 20

[0031] In the above Mathematical Formula 1, [A] is the weight (ppm) of titanium (Ti) contained in the titanium (Ti)-based catalyst, [B] is the weight (ppm) of phosphorus (P) contained in the phosphorus (P)-based heat stabilizer.

[0032] Below, one embodiment of the polyester resin composition will be described in more detail.

[0033] Polyester resin The dicarboxylic acid component may include aromatic dicarboxylic acids having 6 to 12 carbon atoms and aliphatic dicarboxylic acids having 4 to 10 carbon atoms.

[0034] The aforementioned aromatic dicarboxylic acid having 6 to 12 carbon atoms may include terephthalic acid, isophthalic acid, franzicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof.

[0035] 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.

[0036] The dicarboxylic acid component may contain 30 to 70 mol% of the aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 to 70 mol% of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, relative to the total amount of the dicarboxylic acid component.

[0037] The aliphatic diol may include aliphatic diols having 2 to 10 carbon atoms.

[0038] 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.

[0039] The molar ratio of the dicarboxylic acid component and the diol component may be 1.0:0.8 to 1.0:1.2.

[0040] Branching agent The aforementioned crosslinking can consist of a branching agent having three or more crosslinkable functional groups.

[0041] The branching agent may include hydroxyl groups (-OH), carboxyl groups (-COOH), and anhydrides as crosslinkable functional groups. Specifically, the branching agent may be glycerol, trimethylolpropane, pentaerythritol, etc.

[0042] Titanium (Ti) catalyst The titanium (Ti)-based catalyst may include a titanium (Ti)-based esterification catalyst, a titanium (Ti)-based polycondensation catalyst, or a combination thereof.

[0043] The titanium (Ti)-based esterification catalyst may include organic acid chelate titanium compounds and inorganic titanium compounds. The titanium (Ti)-based esterification catalyst may be present in an amount of 20 to 150 ppm, based on the weight of titanium (Ti) contained in the titanium (Ti)-based esterification catalyst.

[0044] The titanium (Ti)-based polycondensation catalyst may include titanium tetraalkoxide compounds or combinations thereof. The titanium (Ti)-based polycondensation catalyst may be present in an amount of 50 to 150 ppm based on the weight of titanium (Ti) contained in the titanium (Ti)-based polycondensation catalyst.

[0045] Phosphorus (P)-based heat stabilizers The phosphorus (P)-based heat stabilizer can be present in an amount of 5 to 200 ppm, based on the weight of phosphorus (P) contained in the phosphorus (P)-based heat stabilizer.

[0046] The phosphorus (P)-based heat stabilizer may include trimethyl phosphonoacetate, triethyl phosphonoacetate, hosphoric acid, phosphorous acid, polyphosphoric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, triphenyl phosphine, or mixtures thereof.

[0047] Physical properties of biodegradable polyester compositions The biodegradable polyester resin composition may have a melt flow index (MI) of 5 g / 10 min or less, measured at 190°C under a load of 2.16 kg, in accordance with ASTM D1238 standards.

[0048] The biodegradable polyester resin composition may have an acid value of 2.5 mg KOH / g or less, measured according to ASTM D664 standards, after analysis by potentiometric titration.

[0049] (Method for producing biodegradable polyester composition) One embodiment provides a method for minimizing macromolecules or aggregates within a final biodegradable polyester composition and for improving various physical properties of the final biodegradable polyester composition in a balanced manner.

[0050] In at least one of the first to third steps, a branching agent, a titanium (Ti)-based catalyst, and a phosphorus (P)-based thermal stabilizer can be added, and the titanium (Ti)-based catalyst and phosphorus (P)-based thermal stabilizer remaining in the fourth step can satisfy the mathematical formula 1.

[0051] Furthermore, the amount of polyester resin with a size of 20 nm or larger can be 10 mass% or less of the total amount (100 mass%) of the biodegradable polyester resin composition obtained in the fourth step.

[0052] As a result, the final biodegradable polyester composition may be identical to that of the embodiment described above.

[0053] Below, explanations that overlap with the above will be omitted, and a manufacturing method of one embodiment will be described step by step.

[0054] Step 1 In the first step, a raw material mixture containing a dicarboxylic acid component and a diol component is produced.

[0055] The second step can be carried out in an esterification reaction tube.

[0056] Step 2 In the second step, the raw material mixture is reacted to produce an oligomer.

[0057] In the second step, the reaction must be carried out efficiently in a short time in order to prevent thermal decomposition. If the temperature at which the second step is carried out is too low, the residence time will be long and unreacted products may be generated. If the reaction temperature is too high, the decomposition of diols, particularly 1,4-butanediol, among the reactants will occur and THF will be generated, so 1,4-butanediol may not be able to participate sufficiently in the reaction and unreacted products may be generated.

[0058] In this regard, since the second step is performed in a temperature range of 130 to 230°C, macromolecules or aggregates can be minimized within the final biodegradable polyester composition.

[0059] Specifically, in the second step, the mixture of raw materials is heated to a temperature range of 130 to 230°C to carry out the esterification reaction, and the by-products, water (H2O) and by-reactants, are removed from the system by a rectification column or by applying a low vacuum to obtain the oligomer.

[0060] Step 3 In the third step, the oligomer can be polycondensed to produce a prepolymer.

[0061] In the third step, the reaction must be carried out efficiently in a short time in order to prevent thermal decomposition. If the temperature at which the third step is performed is too high, the thermal decomposition reaction will be dominant over the polycondensation reaction, resulting not only in the generation of decomposition products but also in a prolonged residence time.

[0062] On the other hand, if the mixture is stirred too quickly in the third step to increase stirring efficiency, decomposition may occur due to the high shear stress caused by the stirring. On the other hand, if the mixture is stirred too slowly, the molecular weight distribution may broaden due to the non-uniform polycondensation reaction, and macromolecules or aggregates may be formed.

[0063] In this regard, the third step is performed at a stirring speed of 20 to 60 rpm in a temperature range of 210 to 250°C, thereby minimizing macromolecules or aggregates in the final biodegradable polyester composition.

[0064] This allows for the acquisition of a prepolymer with a melt flow index (MI) of 5-60 g / 10 min, measured at 190°C under a load of 2.16 kg, in accordance with the ASTM D1238 standard.

[0065] Step 4 In the fourth step, a chain extender can be added to the prepolymer to further increase its viscosity and obtain a polyester resin composition.

[0066] In the fourth step described above, if the prepolymer and the chain extender are mixed at a fast rate or under high shear force for a smooth reaction, the shear stress may increase and decomposition may occur. Similarly, if the reaction is carried out at high temperatures, thermal decomposition may occur, causing a rapid increase in the molecular weight distribution of the final biodegradable polyester.

[0067] Therefore, the fourth step is preferably performed using a static mixer or a dynamic mixer at a temperature range of 120 to 250°C for 1 to 30 minutes.

[0068] Titanium (Ti) catalyst In the first step described above, by making it possible to add some or all of the titanium (Ti)-based catalyst, macromolecules or aggregates can be minimized in the final biodegradable polyester composition.

[0069] Specifically, by adding the titanium (Ti)-based esterification catalyst to the first step, it can be uniformly dispersed at a temperature lower than the esterification reaction temperature. In this way, by uniformly dispersing the titanium (Ti)-based esterification catalyst at a low temperature before carrying out the esterification reaction, oligomers of uniform size can be produced, and unreacted material can be prevented.

[0070] More specifically, the titanium (Ti)-based catalyst can be added to the raw material mixture in the first step at an amount of 5 to 100% by weight relative to the total amount of the titanium (Ti)-based catalyst, with the remainder added to the second step.

[0071] If no titanium (Ti)-based catalyst is added in the first step, and all of the titanium (Ti)-based catalyst is added in the second step, a localized high concentration of catalyst may form in the second step, triggering side reactions. These side reactions may generate decomposition products that form macromolecules or aggregates, and the heterogeneous oligomer formation reaction may broaden the molecular weight distribution.

[0072] More specifically, the titanium (Ti)-based catalyst includes a titanium (Ti)-based esterification catalyst, a titanium (Ti)-based polycondensation catalyst, or a combination thereof, wherein the titanium (Ti)-based esterification catalyst may be added entirely in the first step or divided between the first and second steps, and the titanium (Ti)-based polycondensation catalyst may be added later in the second step or early in the third step.

[0073] Phosphorus (P)-based heat stabilizers In the second and third steps described above, all of the phosphorus (P)-based heat stabilizers can be added.

[0074] Specifically, the phosphorus (P)-based heat stabilizer can be added during the execution of the second step, either later in the second step or early in the third step. However, the phosphorus (P)-based heat stabilizer does not have to be added at the same time as the titanium (Ti)-based catalyst. If the phosphorus (P)-based heat stabilizer is added at the same time as the titanium (Ti)-based catalyst, the activity of the titanium (Ti)-based catalyst decreases, delaying the esterification and / or polycondensation reaction times, causing the prepolymer to decompose, broadening the molecular weight distribution, and potentially generating macromolecules.

[0075] The phosphorus (P)-based heat stabilizer can be added in an amount of 5 to 200 ppm based on the weight of phosphorus (P) contained in the phosphorus (P)-based heat stabilizer. By adding the phosphorus (P)-based heat stabilizer in a titrated amount, the activity of the catalyst does not decrease and thermal decomposition can be prevented. The type of phosphorus (P)-based heat stabilizer is as described above.

[0076] Branching agent In the first to third steps described above, the entirety of the branching agent may be added during the film manufacturing process to improve processability and physical properties.

[0077] Specifically, the branching agent can be added during the raw material mixture of the first step, during the reaction of the second step, in the later stages of the second step, or in the later stages of the third step.

[0078] It can be added during the manufacturing step of the raw material slurry, or during the esterification reaction, or in the later stages of the esterification reaction, or in the early stages of the polycondensation reaction.

[0079] When an excessive amount of the branching agent is added, macromolecules or aggregates are formed, and the preferred range for the amount of branching agent to be added is 10 to 3000 ppm. The type of branching agent is as described above.

[0080] final acquisition The biodegradable polyester resin composition may contain up to 10 mass% of polyester resin with a size of 20 nm or larger, relative to its total amount (100 mass%). A detailed explanation of this is provided above.

[0081] The following description will refer to embodiments of the present invention, but these embodiments are for illustrative purposes only and the scope of the present invention is not limited to them.

[0082] Example 1 (1) Production of biodegradable polyester resin composition Step 1: Terephthalic acid (TPA), adipic acid (AA), and 1,4-butanediol (BD) were added, and an esterification catalyst was added according to the type and content listed in Table 1 below. The raw material mixture was then prepared under stirring.

[0083] Step 2: The raw material mixture from Step 1 was reacted while raising the reaction temperature to 230°C and removing the resulting effluent through a rectification column to produce an oligomer.

[0084] Step 3: A phosphorus-based heat-resistant agent, branching agent, and polycondensation catalyst tetrabutyl titanate (TBT) were added according to the type and content listed in Table 1 below. The reaction temperature was increased for 1 hour as shown in the table, while the pressure in the reaction tube was gradually reduced to below 1 torr. By-reactants and excess butanediol were removed, and the reaction was terminated when the discharge load was reached to obtain the prepolymer. The MI of the obtained prepolymer is shown in Table 1 below.

[0085] Step 4: After drying the obtained biodegradable polyester prepolymer, a chain extension process was carried out in a mixer according to the conditions in Table 1 below to obtain the final biodegradable polyester resin composition.

[0086] Examples 2 to 14 As shown in Tables 1-3 below, biodegradable polyester resin compositions were manufactured by changing the raw materials or processes.

[0087] Comparative Examples 1-12 As shown in Tables 4-6 below, biodegradable polyester resin compositions were produced by changing the raw materials or processes.

[0088] Experimental Example 1: Physical Properties of Biodegradable Polyester Resin Compositions The physical properties of the biodegradable polyester resin compositions of the examples and comparative examples were evaluated using the following method, and the results are shown in Tables 1 to 6 below.

[0089] In accordance with MI:ASTM D1238 standard, after sample loading, the weight of polyester extruded through the orifice of a capillary rheometer was measured under a load of 2.16 kg for 10 minutes at 190°C.

[0090] Acid value: After analysis by potentiometric titration, the acid value was calculated according to ASTM D664 standard.

[0091] Molecular weight distribution (PDI) was measured using gel permeation chromatography (GPC, Agilent Technology 1200 Series) with chloroform as the solvent and polystyrene as the standard. The column and detector were set to 40°C, and the measurement was performed at a flow rate of 1 mL / min.

[0092] Molecular size: Measured at a wavelength of 661 nm using a DLS instrument (Wyatt, model: Nanostar). The sample was dissolved in chloroform at a concentration of 1.0 mg / mL for measurement.

[0093] Experimental Example 2: Physical Properties of Biodegradable Polyester Resin Film Biodegradable polyester resin films were manufactured for the examples and comparative examples, and their physical properties were evaluated using the following methods. The results are shown in Tables 1 to 6 below.

[0094] A 50 μm film was produced by extruding a final biodegradable polyester resin composition using a single-sheet extruder.

[0095] The tear strength of the manufactured film was measured according to the ASTM D1004 standard. The test was conducted using an Instron UTM 4520 tensile testing machine under conditions of 23°C, 50% relative humidity, and a tensile speed of 500 mm / min. The tear strength was expressed as the MD tear strength along the longitudinal direction of the film.

[0096] [Table 1]

[0097] [Table 2]

[0098] [Table 3]

[0099] [Table 4]

[0100] [Table 5]

[0101] [Table 6]

[0102] The substances used in Tables 1-6 are as follows:

[0103] BD: 1,4-Butanediol TPA: Terephthalic acid AA: Adipic acid TEP: Triethyl phosphate TMP: Trimethylol propane PTT: Pentaerythritol TBT: Tetrabutyl titanate Catalyst 1: Inorganic titanium catalyst (SPC-124) Catalyst 2: Citrate-based titanium catalyst

[0104] According to Tables 1 to 6, if a branching agent, a titanium (Ti)-based catalyst, and a phosphorus (P)-based heat stabilizer are added to at least one of the first to third steps, and the titanium (Ti)-based catalyst and the phosphorus (P)-based heat stabilizer satisfy the mathematical formula 1, a biodegradable polyester resin composition containing 10 mass% or less of polyester resin with a size of 20 nm or more is obtained, and the tear strength of the biodegradable polyester resin film is enhanced.

[0105] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. A polyester resin comprising a residue of a dicarboxylic acid component and a residue of a diol component; titanium (Ti); and phosphorus (P), a biodegradable polyester resin composition, The biodegradable polyester resin composition contains 10 mass% or less of polyester resin particles with a size of 20 nm or larger as measured by DLS, based on the total amount (100 mass%) of the composition. The biodegradable polyester resin composition wherein the content ratio of titanium (Ti) and phosphorus (P) contained in the biodegradable polyester resin composition satisfies the following mathematical formula 1. [Mathematical formula 1] 1<[A] / [B]<20 In the above mathematical formula 1, [A] is the weight (ppm) of the titanium (Ti), [B] is the weight (ppm) of the phosphorus (P) mentioned above.

2. The dicarboxylic acid component includes aromatic dicarboxylic acids having 6 to 12 carbon atoms and aliphatic dicarboxylic acids having 4 to 10 carbon atoms. The aforementioned aromatic dicarboxylic acid having 6 to 12 carbon atoms includes terephthalic acid, isophthalic acid, franciocarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof. The biodegradable polyester resin composition according to claim 1, wherein the aliphatic dicarboxylic acid having 4 to 10 carbon atoms comprises adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, cyclic fatty acids, diester derivatives thereof, anhydrides thereof, or mixtures thereof.

3. The biodegradable polyester resin composition according to claim 1, wherein the dicarboxylic acid component comprises 30 to 70 mol% of the aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 to 70 mol% of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the dicarboxylic acid component.

4. The aliphatic diol includes aliphatic diols having 2 to 10 carbon atoms. The biodegradable polyester resin composition according to claim 1, wherein 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.

5. The biodegradable polyester resin composition according to claim 1, wherein the molar ratio of the dicarboxylic acid component and the diol component is 1.0:0.8 to 1.0:1.

2.

6. The biodegradable polyester resin composition according to claim 1, wherein the crosslinking comprises a branching agent having three or more crosslinkable functional groups.

7. The biodegradable polyester resin composition according to claim 1, wherein the titanium (Ti) is derived from a titanium (Ti)-based esterification catalyst, a titanium (Ti)-based polycondensation catalyst, or a combination thereof.

8. The biodegradable polyester resin composition according to claim 7, wherein the titanium (Ti) contained in the biodegradable polyester resin composition originates from 0 to 150 ppm of the titanium (Ti)-based esterification catalyst and from 50 to 150 ppm of the titanium (Ti)-based polycondensation catalyst.

9. The biodegradable polyester resin composition according to claim 1, wherein the phosphorus (P) is derived from a phosphorus (P)-based heat stabilizer.

10. The biodegradable polyester resin composition according to claim 9, wherein the phosphorus (P) is derived from a phosphorus (P)-based heat stabilizer in an amount of 5 to 200 ppm.

11. The biodegradable polyester resin composition according to claim 1, wherein the melt flow index (MI) measured at 190°C under a load of 2.16 kg in accordance with the ASTM D1238 standard is 5 g / 10 min or less.

12. The biodegradable polyester resin composition according to claim 1, wherein the acid value measured in accordance with ASTM D664 after analysis by potentiometric titration is 2.5 mg KOH / g or less.

13. A first step of producing a raw material mixture containing a dicarboxylic acid component and a diol component, A second step involves reacting the aforementioned raw material mixture to produce an oligomer, A third step involves polycondensing the oligomer to produce a prepolymer, The fourth step involves adding a chain extender to the prepolymer to obtain a polyester resin composition. In at least one of the first to third steps, a branching agent, a titanium (Ti)-based catalyst, and a phosphorus (P)-based thermal stabilizer are added, respectively. In the fourth step, the polyester resin composition contains 10 mass% or less of polyester resin particles having a size of 20 nm or more, relative to the total amount (100 mass%) of the polyester resin composition. A method for producing a biodegradable polyester resin composition, wherein in the fourth step, the content ratio of titanium (Ti) and phosphorus (P) contained in the biodegradable polyester resin composition satisfies the following mathematical formula 1. [Mathematical formula 1] 1<[A] / [B]<20 In the above mathematical formula 1, [A] is the weight (ppm) of the titanium (Ti), [B] is the weight (ppm) of the phosphorus (P) mentioned above.

14. The method for producing the biodegradable polyester resin composition according to claim 13, wherein the second step is carried out in a temperature range of 130 to 230°C.

15. The method for producing a biodegradable polyester resin composition according to claim 13, wherein the prepolymer obtained in the third step has a melt flow index (MI) of 5 to 60 g / 10 min, measured at 190°C under a load of 2.16 kg in accordance with the ASTM D1238 standard.

16. The biodegradable polyester resin composition according to claim 13, wherein the fourth step is performed using a static mixer or a dynamic mixer at a temperature range of 120 to 250°C for 1 to 30 minutes.

17. The polyester resin composition according to claim 13, wherein all of the phosphorus (P)-based heat stabilizer is added in the second and third steps described above.

18. The polyester resin composition according to claim 13, wherein all of the branching agent is added in the first to third steps described above.