Biodegradable polyester resin composition, method for producing the same, and biodegradable molded article containing the same

Abstract

The example includes a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and has a biodegradability of 1.7 or more per aliphatic carboxylic acid. The biodegradability per aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the ratio of the aliphatic dicarboxylic acid in the total dicarboxylic acids, and the biodegradability after 9 weeks is 85% or more, and provides a biodegradable polyester resin composition.

Description

Technical Field

[0001] The examples relate to a biodegradable polyester resin composition, a method for producing the same, and a biodegradable molded article containing the same.

Background Art

[0002] In recent years, as the concern about environmental problems has increased, solutions to the treatment problems of various daily necessities, particularly disposable products, have been sought. Specifically, polymer materials are inexpensive and have excellent properties such as processability, and are widely used to manufacture various products such as films, fibers, packaging materials, bottles, and containers. However, when the life of the used product ends, harmful substances are emitted during incineration, and it takes hundreds of years depending on the type to be completely decomposed naturally, which has the disadvantage.

[0003] In order to overcome these limitations of polymers, research on biodegradable polymers that are decomposed within a short time has been actively conducted. As biodegradable polymers, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), etc. are used.

[0004] These biodegradable resin compositions are disclosed in Korean Patent Laid-Open No. 2012-0103158 and the like.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The examples aim to provide a biodegradable polyester resin composition that has an appropriate initial degree of hydrolysis when exposed to moisture, has a high degree of hydrolysis in water during disposal, and has a high degree of biodegradability, a method for producing the same, and a biodegradable molded article containing the same.

Means for Solving the Problems

[0006] The method for producing a biodegradable polyester resin composition according to the examples includes the steps of: forming a prepolymer by esterifying a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; forming a condensation polymer composition by condensation polymerization of the prepolymer; and reacting the condensation polymer composition with a silicon-based hydrolysis resistant agent.

[0007] In the method for producing a biodegradable polyester resin composition according to one embodiment, the step of adding a metal salt may be further included.

[0008] In the method for producing a biodegradable polyester resin composition according to one embodiment, the metal salt may contain an iron element.

[0009] In the method for producing a biodegradable polyester resin composition according to one embodiment, the hydrolysis-resistant agent may include a silane containing two or more functional groups.

[0010] In the method for producing a biodegradable polyester resin composition according to one embodiment, the hydrolysis-resistant agent may contain an epoxy group or an alkoxy group.

[0011] In the method for producing a biodegradable polyester resin composition according to one embodiment, the step of reacting the polymerization condensation composition and the silicone-based hydrolysis resistant agent may include a step of reacting the polymerization condensation composition and the silicone-based hydrolysis resistant agent at a temperature of about 180°C to about 260°C for 5 minutes to 60 minutes.

[0012] In the method for producing a biodegradable polyester resin composition according to one example, the acid value may be about 2.0 mg KOH / g or less.

[0013] In the method for producing a biodegradable polyester resin composition according to one embodiment, the degree of hydrolysis after one week is approximately 35% to approximately 60%, and the degree of hydrolysis after one week may be the rate of decrease in the number average molecular weight of the biodegradable polyester resin composition compared to its initial state when the biodegradable polyester film is placed for approximately one week under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity.

[0014] One example of a biodegradable polyester resin composition comprises a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, a metal salt, and a silicon element.

[0015] In one embodiment of the biodegradable polyester resin composition, the metal salt contains an iron element, and the mass ratio of the iron element to the silicon element may be about 0.1 to about 0.7.

[0016] In one embodiment of the biodegradable polyester resin composition, the degree of hydrolysis after one week is approximately 35% to approximately 60%, and the degree of hydrolysis after approximately three weeks is approximately 85% or more. The degree of hydrolysis after one week and the degree of hydrolysis after three weeks can be measured by the following measurement method.

[0017] [Measurement method] The degree of hydrolysis after one week is the rate of decrease in the number average molecular weight of the biodegradable polyester resin composition compared to its initial state when the biodegradable polyester resin composition is left for about one week under high temperature and high humidity conditions of about 80°C and about 100% humidity, and the degree of hydrolysis after three weeks is the rate of decrease in the number average molecular weight of the biodegradable polyester resin composition compared to its initial state when the biodegradable polyester resin composition is left for about three weeks under high temperature and high humidity conditions of about 80°C and about 100% humidity.

[0018] In the biodegradable polyester resin composition according to one embodiment, the content of the iron element may be about 1 ppm to about 100 ppm, and the content of the silicon element may be about 1 ppm to about 150 ppm.

[0019] The biodegradable polyester resin composition according to one embodiment further contains nanocellulose, and the nanocellulose is a biodegradable polyester resin composition containing sulfur.

[0020] In the biodegradable polyester resin composition according to one embodiment, the wet hardness reduction rate is about 15% or less, and the wet hardness reduction rate can be measured by the following measurement method.

[0021] [Measurement method] The biodegradable polyester resin composition is processed to produce a polyester block having a thickness of about 2.5 mm, the initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at about 30 °C for about 24 hours are measured, and the wet hardness reduction rate is the value obtained by dividing the difference between the wet hardness and the initial hardness by the initial hardness.

[0022] The biodegradable molded product according to the embodiment contains a polyester resin containing a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, a metal salt, and a silicon element.

[0023] In the biodegradable polyester molded product according to one embodiment, the metal salt contains an iron element, and the mass ratio of the iron element to the silicon element may be about 0.1 to about 0.7.

[0024] In the biodegradable polyester molded product according to one embodiment, the degree of hydrolysis after one week is about 35% to about 60%, and the degree of hydrolysis after about three weeks is about 85% or more. The degree of hydrolysis after one week and the degree of hydrolysis after three weeks can be measured by the following measurement method.

[0025] [Measurement method] The degree of hydrolysis after one week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for about one week under high temperature and high humidity conditions of a temperature of about 80 °C and a humidity of about 100%. The degree of hydrolysis after three weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for about three weeks under high temperature and high humidity conditions of a temperature of about 80 °C and a humidity of about 100%.

[0026] In the biodegradable polyester molded article according to one embodiment, the content of the iron element is from about 1 ppm to about 100 ppm, and the content of the silicon element may be from about 1 ppm to about 150 ppm.

[0027] The biodegradable polyester molded article according to one embodiment further contains nanocellulose, and the nanocellulose may contain sulfur.

[0028] In the biodegradable polyester molded article according to one embodiment, the wet hardness reduction rate is about 15% or less, and the wet hardness reduction rate can be measured by the following measurement method.

[0029] [Measurement method] The biodegradable polyester molded article is processed to produce a polyester block having a thickness of about 2.5 mm. The initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at about 30 °C for about 24 hours are measured. The wet hardness reduction rate is the value obtained by dividing the difference between the wet hardness and the initial hardness by the initial hardness. [Advantages of the Invention]

[0030] The method for producing the biodegradable polyester resin composition according to the examples includes a step of reacting the condensation polymerization composition with a silicone-based hydrolysis resistant agent. As a result, the biodegradable polyester resin composition according to the examples may have improved hydrolysis resistance. Furthermore, the silicone-based hydrolysis resistant agent can function as a coupling agent that couples the polymer resin contained in the condensation polymerization composition.

[0031] As a result, the silicone-based hydrolysis resistant agent can improve the degree of polymerization of the biodegradable polyester resin composition according to the examples.

[0032] Therefore, the biodegradable polyester resin composition according to the examples contains the aforementioned silicone hydrolysis-resistant agent and may have hydrophobic properties, or it may have an appropriate degree of hydrolysis.

[0033] Furthermore, the method for producing the biodegradable polyester resin composition according to the examples may further include a step of adding a metal salt. The metal salt may improve the degree of biodegradation of the biodegradable polyester resin composition according to the examples. In addition, the metal salt may improve the degree of late hydrolysis in the biodegradable polyester resin composition according to the examples. That is, the biodegradable polyester resin composition according to the examples may have an appropriate metal content and an appropriate silicon element content.

[0034] As a result, the biodegradable polyester resin composition according to the examples may have improved physical properties during the actual period of use and may be easily biodegradable after use.

[0035] The biodegradable polyester resin compositions according to the examples can be efficiently applied to packaging films and the like. That is, films made from the biodegradable polyester resin compositions according to the examples can be used for ordinary purposes such as packaging. In this case, the biodegradable polyester resin compositions according to the examples may have a low degree of hydrolysis initially, and the biodegradable polyester film can maintain a certain level of mechanical and chemical properties within the user's normal usage period.

[0036] In addition, since the biodegradable polyester resin composition according to the examples has a high degree of biodegradability, the film produced using the biodegradable polyester resin composition according to the examples may decompose easily when discarded after use. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram showing the apparatus for producing the polyester resin composition according to the examples. [Figure 2] This figure shows an example of a biodegradable molded article formed by the polyester resin composition according to the examples. [Modes for carrying out the invention]

[0038] The invention will be described in detail below with concrete examples. The concrete examples are not limited to those disclosed below and can be modified into various forms as long as the gist of the invention remains unchanged.

[0039] In this specification, when a part is said to "include" a component, unless otherwise stated, this does not mean that it excludes other components, but rather that it may further include other components.

[0040] Furthermore, it should be understood that all numerical ranges indicating physical properties, dimensions, etc., of the components described herein are modified by the term "approximately" unless otherwise specified.

[0041] The terms first, second, primary, secondary, etc., used herein are used to describe various components, and such components are not limited by these terms. The terms are used solely for the purpose of distinguishing one component from another.

[0042] In this specification, ppm is a mass-based unit. The ppm is one millionth of the total mass. That is, the ppm is 0.0001 wt% of the total mass.

[0043] The biodegradable polyester resin compositions according to the examples contain a biodegradable polyester resin. The biodegradable polyester resin compositions according to the examples may contain the biodegradable polyester resin alone or together with other resins or additives.

[0044] The biodegradable polyester resin comprises a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The biodegradable polyester resin comprises a diol residue, an aromatic dicarboxylic acid residue, and an aliphatic dicarboxylic acid residue. The diol residue is derived from the diol, the aromatic dicarboxylic acid residue is derived from the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid residue is derived from the aliphatic dicarboxylic acid. The biodegradable polyester resin comprises a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component. Similarly, the diol component may be derived from the diol, the aromatic dicarboxylic acid component may be derived from the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid component may be derived from the aliphatic dicarboxylic acid.

[0045] In the description of the biodegradable polyester resin composition by example, the diol residue may also be represented as a diol. In the biodegradable polyester resin, the dicarboxylic acid residue may also be represented as a dicarboxylic acid. Furthermore, the residue may also be represented as the component.

[0046] The diol may be an aliphatic diol. The diol may be a bio-derived diol. The diol may be ethanediol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1, At least one of the following groups may be selected: 3-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-octadecanediol, or derivatives thereof.

[0047] The diol may be selected from the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, diethylene glycol, neopentyl glycol, or derivatives thereof, with at least one of these being selected.

[0048] The diol may be selected from the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or derivatives thereof, with at least one selected from these.

[0049] The diol may include 1,4-butanediol or a derivative thereof.

[0050] The aromatic dicarboxylic acid may be at least one selected from the group consisting of phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, anthracenedicarboxylic acid, phenantradicarboxylic acid, or derivatives thereof.

[0051] The aromatic dicarboxylic acid may be selected from at least one of the group consisting of terephthalic acid, dimethyl terephthalate, 2,6-naphthalenedicarboxylic acid, isophthalic acid, or derivatives thereof.

[0052] The aromatic dicarboxylic acid may include terephthalic acid, dimethyl terephthalate, or derivatives thereof.

[0053] The aliphatic dicarboxylic acid may be at least one selected from the group consisting of oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, or derivatives thereof.

[0054] The aliphatic dicarboxylic acid may be selected from the group consisting of adipic acid, succinic acid, sebacic acid, or derivatives thereof, with at least one of these being selected.

[0055] The aliphatic dicarboxylic acid may include adipic acid or a derivative thereof.

[0056] In the biodegradable polyester resin, the molar ratio of the total diol residues including the diol to the total dicarboxylic acid residues including the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid may be about 1:0.9 to about 1:1.1. The molar ratio of the total diol residues to the total dicarboxylic acid residues may be about 1:0.95 to about 1:1.05.

[0057] In the biodegradable polyester resin, the molar ratio of the aromatic dicarboxylic acid residue to the aliphatic dicarboxylic acid residue may be about 3:7 to about 7:3. In the biodegradable polyester resin, the molar ratio of the aromatic dicarboxylic acid residue to the aliphatic dicarboxylic acid residue may be about 3.3:6.7 to about 6.7:3.3. In the biodegradable polyester resin, the molar ratio of the aromatic dicarboxylic acid residue to the aliphatic dicarboxylic acid residue may be about 4:6 to about 6:4. In the biodegradable polyester resin, the molar ratio of the aromatic dicarboxylic acid residue to the aliphatic dicarboxylic acid residue may be about 4.2:5.8 to about 5:5.

[0058] The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of approximately 90 mol% or more, based on the total diol content. The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of approximately 95 mol% or more, based on the total diol content. The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of approximately 98 mol% or more, based on the total diol content.

[0059] The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of approximately 30 mol% to approximately 70 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of approximately 35 mol% to approximately 65 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of approximately 40 mol% to approximately 59 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of approximately 43 mol% to approximately 53 mol%, based on the total dicarboxylic acid content.

[0060] The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of approximately 30 mol% to approximately 70 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of approximately 35 mol% to approximately 65 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of approximately 41 mol% to approximately 60 mol%, based on the total dicarboxylic acid content. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of approximately 47 mol% to approximately 57 mol%, based on the total dicarboxylic acid content.

[0061] Furthermore, the biodegradable polyester resin may include a first block and a second block. The biodegradable polyester resin may have a molecular structure in which the first block and the second block are alternately bonded.

[0062] The first block may include the diol residue and the aromatic dicarboxylic acid residue. The first block may be formed by the esterification reaction of the diol and the aromatic dicarboxylic acid. The first block may include only the diol residue and the aromatic dicarboxylic acid residue. The first block may include only the repeating units formed by the esterification reaction of the diol and the aromatic dicarboxylic acid. That is, the first block may represent the sum of the repeating units of the diol and the aromatic dicarboxylic acid before they are bonded to the aliphatic dicarboxylic acid.

[0063] The second block may include the diol residue and the aliphatic dicarboxylic acid residue. The second block may be formed by the esterification reaction of the diol and the aliphatic dicarboxylic acid. The second block may include only the diol residue and the aliphatic dicarboxylic acid residue. The second block may include only the repeating units formed by the esterification reaction of the diol and the aliphatic dicarboxylic acid. That is, the second block may represent the sum of the repeating units of the diol and the aliphatic dicarboxylic acid before the aromatic dicarboxylic acid is bonded to them.

[0064] In the biodegradable polyester resin, the ratio (X / Y) of the number of first blocks (X) to the number of second blocks (Y) may be about 0.5 to about 1.5. In the biodegradable polyester resin, the ratio (X / Y) of the number of first blocks (X) to the number of second blocks (Y) may be about 0.6 to about 1.4. In the biodegradable polyester resin, the ratio (X / Y) of the number of first blocks (X) to the number of second blocks (Y) may be about 0.7 to about 1.3. In the biodegradable polyester resin, the ratio (X / Y) of the number of first blocks (X) to the number of second blocks (Y) may be about 0.75 to about 1.2. Also, in the biodegradable polyester resin, the ratio (X / Y) of the number of first blocks (X) to the number of second blocks (Y) may be 0.8 to 1. The number of the first blocks may be even smaller than the number of the second blocks.

[0065] The number of the first blocks may be approximately 30 to approximately 300. The number of the first blocks may be approximately 40 to approximately 250. The number of the first blocks may be approximately 50 to approximately 220. The number of the first blocks may be approximately 60 to approximately 200. The number of the first blocks may be approximately 70 to approximately 200. The number of the first blocks may be approximately 75 to approximately 200.

[0066] The number of the first blocks may vary depending on the content of the aromatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the alternation ratio described later. In other words, the number of the first blocks may increase as the molar ratio of the aromatic dicarboxylic acid increases, as the molecular weight of the biodegradable polyester resin increases, and as the alternation ratio described later increases.

[0067] The number of the second blocks may be approximately 30 to approximately 300. The number of the second blocks may be approximately 40 to approximately 250. The number of the second blocks may be approximately 50 to approximately 220. The number of the second blocks may be approximately 60 to approximately 200. The number of the second blocks may be approximately 70 to approximately 200. The number of the second blocks may be approximately 75 to approximately 200.

[0068] When the biodegradable polyester resin includes the first block and the second block within the above range, the biodegradable polyester resin composition according to the example may have appropriate mechanical strength and appropriate biodegradability. Furthermore, when the biodegradable polyester resin includes the first block and the second block within the above range, the biodegradable polyester resin composition according to the example may have improved flexibility and improved rigidity. This allows the biodegradable polyester resin composition according to the example to be easily used in injection molded products and the like. Furthermore, when the biodegradable polyester resin includes the first block and the second block within the above range, the biodegradable polyester resin composition according to the example may have appropriate resistance to ultraviolet light and appropriate biodegradability.

[0069] The first block may be represented by the following formula 1.

[0070] [ka]

[0071] Here, R1 is a substituted or unsubstituted allylene group having 6 to 20 carbon atoms, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and m may be 1 to 20.

[0072] R1 may be a substituted or unsubstituted phenylene group, and R2 may be a butylene group.

[0073] The second block may be represented by the formula shown in 2 below.

[0074] [ka]

[0075] Here, R3 and R4 are each independently substituted or unsubstituted alkylene groups having 1 to 20 carbon atoms, and n may be 1 to 20.

[0076] R3 and R4 may be butylene groups.

[0077] The biodegradable polyester resin may have a structure in which the first block and the second block are alternately bonded to each other. The biodegradable polyester resin may also be represented by the following chemical formula 3.

[0078] [ka]

[0079] Here, R1 is a substituted or unsubstituted allylene group having 6 to 20 carbon atoms, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and m may be 1 to 20. Also, R3 and R4 are each independently substituted or unsubstituted alkylene groups having 1 to 20 carbon atoms, and n may be 1 to 20.

[0080] The diol residue may include a residue of 1,4-butanediol or a derivative thereof, the aromatic dicarboxylic acid residue may include a residue of terephthalic acid or a derivative thereof, and the aliphatic dicarboxylic acid residue may include a residue of adipic acid or a derivative thereof.

[0081] For example, the biodegradable polyester resin may include a first block containing residues of 1,4-butanediol or its derivatives, and residues of terephthalic acid or its derivatives.

[0082] Alternatively, the biodegradable polyester resin may include a first block comprising a residue of 1,4-butanediol or a derivative thereof, and a residue of dimethyl terephthalate or a derivative thereof.

[0083] The biodegradable polyester resin may also include a second block containing residues of 1,4-butanediol or its derivatives, and residues of adipic acid or its derivatives.

[0084] Alternatively, the biodegradable polyester resin may include a second block containing residues of 1,4-butanediol or its derivatives, and residues of succinic acid or its derivatives.

[0085] A biodegradable polyester resin according to an embodiment of the present invention may comprise a first block containing a residue of 1,4-butanediol or a derivative thereof, and a residue of terephthalic acid or a derivative thereof, and a second block containing a residue of 1,4-butanediol or a derivative thereof, and a residue of adipic acid or a derivative thereof.

[0086] The first block may be represented by the following formula 4, and the second block may be represented by the following formula 5.

[0087] [ka]

[0088] Here, m may range from 1 to 20.

[0089] [ka]

[0090] Here, n may range from 1 to 20.

[0091] The biodegradable polyester resin may be represented by the following chemical formula 6.

[0092] [ka]

[0093] Here, m is between 1 and 20, and n may also be between 1 and 20.

[0094] When the first and second blocks satisfy the above configuration, it may be even more advantageous in providing a biodegradable polyester sheet, film, or molded article that is excellent in biodegradability and water degradability, and has improved physical properties.

[0095] Furthermore, when the biodegradable polyester resin includes the first block and the second block within the above range, the biodegradable polyester resin composition according to the example may have appropriate mechanical properties and appropriate UV resistance characteristics.

[0096] Because the first and second blocks have the above-described characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0097] Since the first and second blocks have the characteristics described above, the biodegradable polyester resin composition according to the example may have appropriate UV resistance properties.

[0098] Since the first and second blocks have the characteristics described above, the biodegradable polyester resin composition according to the example may have an appropriate biodegradation rate.

[0099] Since the first and second blocks have the characteristics described above, the biodegradable polyester resin composition according to the example may have an appropriate hydrolysis rate.

[0100] The biodegradable polyester resin may further contain a branching agent. The branching agent may contain at least one from the group consisting of trivalent or higher alcohols, anhydrides, or trivalent or higher carboxylic acids. The branching agent can react with the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. As a result, the branching agent may be included in the biodegradable polyester resin as part of its molecular structure.

[0101] The trivalent or higher alcohol may be selected from at least one of the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0102] The aforementioned trivalent or higher carboxylic acids include methane tricarboxylic acid, ethane tricarboxylic acid, citric acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzenetricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, or benzene-1,2,4,5-tetracarboxylic acid At least one of the group consisting of (acid) may be selected.

[0103] The aforementioned anhydride may contain at least one from the group consisting of trimellitic anhydride, succinic anhydride, methylsuccinic anhydride, ethylsuccinic anhydride, 2,3-butanedicarboxylic acid anhydride, 2,4-pentanedicarboxylic acid anhydride, 3,5-heptanedicarboxylic acid anhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, maleic anhydride, dodecylsuccinic acid anhydride, or pyromellitic anhydride.

[0104] The branching agent may be included in the biodegradable polyester resin in an amount of approximately 0.1 wt% to approximately 5 wt% based on the total biodegradable polyester resin. The branching agent may be included in the biodegradable polyester resin in an amount of approximately 0.1 wt% to approximately 3 wt% based on the total biodegradable polyester resin. The branching agent may be included in the biodegradable polyester resin in an amount of approximately 0.1 wt% to approximately 1 wt% based on the total biodegradable polyester resin.

[0105] Since the biodegradable polyester resin contains the branching agent within the above range, the biodegradable polyester resin composition according to the example may have appropriate mechanical properties and appropriate biodegradability.

[0106] The biodegradable polyester resin may further contain a polycarbonate diol. The polycarbonate diol may be included in the biodegradable polyester resin bound to its molecular structure.

[0107] The polycarbonate diol can be produced by a dehydration condensation reaction of a carbonate and a polyhydric alcohol. The carbonate may be at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, or ethylene carbonate. The polyhydric alcohol may be at least one selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, 1,6-hexanediol, or 1,2-propanediol.

[0108] The weight-average molecular weight of the polycarbonate diol may be about 500 to about 5000. The weight-average molecular weight of the polycarbonate diol may be about 700 to about 4000. The weight-average molecular weight of the polycarbonate diol may be about 800 to about 3500.

[0109] Furthermore, the viscosity of the polycarbonate diol may be approximately 300 cps to approximately 20,000 cps. The viscosity of the polycarbonate diol may be approximately 400 cps to approximately 15,000 cps. The viscosity of the polycarbonate diol may be approximately 500 cps to approximately 14,000 cps. The viscosity of the polycarbonate diol can be measured at room temperature according to ASTM / ISO 2555.

[0110] The OH value of the polycarbonate diol may be approximately 20 mg KOH / g to approximately 350 mg KOH / g. The OH value of the polycarbonate diol may be approximately 30 mg KOH / g to approximately 300 mg KOH / g.

[0111] The polycarbonate diol may be included in the biodegradable polyester resin in an amount of about 0.1 to about 5 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The polycarbonate diol may be included in the biodegradable polyester resin in an amount of about 0.5 to about 3 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The polycarbonate diol may be included in the biodegradable polyester resin in an amount of about 1 to about 3 parts by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0112] Since the polycarbonate diol has the characteristics described above, the biodegradable polyester resin composition according to the examples may have appropriate wet hardness, appropriate mechanical properties, appropriate solvent resistance, appropriate degree of hydrolysis, and appropriate degree of biodegradation.

[0113] The biodegradable polyester resin may further contain a polyether polyol. The polyether polyol may be included in the biodegradable polyester resin by being molecularly bonded to it.

[0114] The aforementioned polyether polyol may be produced by adding propylene oxide (PO) or ethylene oxide (EO) to an initiator having two or more activated hydrogen atoms (-OH or NH2). Examples of the aforementioned polyether polyol include polypropylene glycol, polyethylene glycol, or polytetramethylene glycol.

[0115] The weight-average molecular weight of the polyether polyol may be about 500 to about 5000. The weight-average molecular weight of the polyether polyol may be about 700 to about 4000. The weight-average molecular weight of the polyether polyol may be about 800 to about 3500.

[0116] Furthermore, the viscosity of the polyether polyol may be approximately 300 cps to approximately 20,000 cps. The viscosity of the polyether polyol may be approximately 400 cps to approximately 15,000 cps. The viscosity of the polyether polyol may be approximately 500 cps to approximately 14,000 cps. The viscosity of the polyether polyol can be measured at room temperature according to ASTM / ISO 2555.

[0117] The polyether polyol may be included in the biodegradable polyester resin in an amount of about 0.1 parts by weight to about 5 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The polyether polyol may be included in the biodegradable polyester resin in an amount of about 0.5 parts by weight to about 3 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The polyether polyol may be included in the biodegradable polyester resin in an amount of about 1 part by weight to about 3 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0118] Since the polyether polyol has the characteristics described above, the biodegradable polyester resin composition according to the examples may have appropriate wet hardness, appropriate mechanical properties, appropriate solvent resistance, appropriate degree of hydrolysis, and appropriate degree of biodegradation.

[0119] The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 30 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 50 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 70 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 80 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 90 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of approximately 95 wt% or more based on the weight of the total composition. The biodegradable polyester resin composition according to the examples may contain the biodegradable resin in an amount of about 99 wt% or more based on the weight of the total composition. The maximum content of the biodegradable resin in the biodegradable polyester resin composition according to the examples may be about 100 wt% based on the weight of the total composition.

[0120] The biodegradable polyester resin composition according to the examples may further contain a reinforcing material. The reinforcing material can improve the mechanical properties of the biodegradable polyester resin composition according to the examples and the film or molded article produced therefrom. The reinforcing material can also adjust the ultraviolet deformation characteristics of the biodegradable polyester resin composition according to the examples. The reinforcing material can also adjust the hydrolysis characteristics of the biodegradable polyester resin composition according to the examples. The reinforcing material can also adjust the biodegradability of the biodegradable polyester resin according to the examples.

[0121] The reinforcing material may be a fiber derived from biomass. The reinforcing material may be a fiber made of an organic substance. The reinforcing material may be nanocellulose.

[0122] The nanocellulose may be one or more selected from the group consisting of nanocrystalline cellulose, cellulose nanofiber, microfibrillated cellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, cellulose acetate, methylcellulose, ethylcellulose, propylcellulose, butylcellulose, pentylcellulose, hexylcellulose, or cyclohexylcellulose.

[0123] The nanocellulose may contain ionically bonded metals. The nanocrystalline cellulose may contain the element sodium. The nanocrystalline cellulose may also contain sulfate. The nanocrystalline cellulose may also contain carboxylates. The nanocrystalline cellulose may be cellulose hydrogen sulphate sodium salt.

[0124] The nanocellulose may be represented by the following chemical formula 7.

[0125] [ka]

[0126] Here, x may be between 1 and 35, and y may be between 1 and 10. Alternatively, x may be between 15 and 35, and y may be between 1 and 10.

[0127] The aforementioned nanocellulose is approximately 200 m 2 / g~about 600m 2It may also have a specific surface area of ​​250 m / g. The nanocellulose is approximately 250 m 2 / g~about 500m 2 It may also have a specific surface area of ​​ / g.

[0128] The weight-average molecular weight of the nanocellulose may be approximately 10,000 g / mol to approximately 40,000 g / mol. The weight-average molecular weight of the nanocrystalline cellulose may be approximately 11,000 g / mol to approximately 35,000 g / mol.

[0129] The water content of the nanocrystalline cellulose may be about 2 wt% to about 8 wt%. The water content of the nanocrystalline cellulose may be about 4 wt% to about 6 wt%.

[0130] The average diameter of the nanocellulose may be about 0.5 nm to about 10 nm. The average diameter of the nanocellulose may be about 1 nm to about 8 nm. The average diameter of the nanocellulose may be about 1.5 nm to about 7 nm.

[0131] The average length of the nanocellulose may be approximately 20 nm to approximately 300 nm. The average length of the nanocellulose may be approximately 30 nm to approximately 180 nm. The average length of the nanocellulose may be approximately 35 nm to approximately 150 nm.

[0132] By ensuring that the diameter and length of the nanocellulose satisfy the above range, the biodegradability and physical properties of the biodegradable polyester resin, or the biodegradable polyester sheets, films, and molded articles obtained using it, can be further improved.

[0133] The diameter and length of the nanocellulose can be measured by atomic force microscopy while it is dispersed in water.

[0134] The sulfur content of the nanocellulose may be about 0.1 wt% to about 1.2 wt% based on the total nanocrystalline cellulose.

[0135] The pH of the nanocellulose may be 5 to 8. The pH of the nanocellulose may be 6 to 8.

[0136] The zeta potential of the nanocellulose may be approximately -25mV to approximately -50mV. The zeta potential of the nanocellulose may also be approximately -30mV to approximately -45mV.

[0137] The nanocellulose may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.01 parts by weight to about 2 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.03 parts by weight to about 1.5 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.04 parts by weight to about 1.2 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.05 parts by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0138] Because the nanocellulose has the characteristics described above, it can be uniformly dispersed in the biodegradable polyester resin composition according to the examples.

[0139] Because the nanocellulose has the characteristics described above, it can improve the mechanical properties of the biodegradable polyester resin composition according to the examples.

[0140] Furthermore, the nanocellulose functions as a crystal nucleating agent, improving the crystallization rate of the biodegradable polyester resin composition according to the examples. This allows the nanocellulose to increase the crystallization temperature of the biodegradable polyester resin composition according to the examples.

[0141] Since the nanocellulose has the characteristics described above, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance properties.

[0142] Since the nanocellulose has the characteristics described above, the biodegradable polyester resin composition according to the examples may have an appropriate biodegradation rate.

[0143] Since the nanocellulose has the characteristics described above, the biodegradable polyester resin composition according to the examples may have an appropriate hydrolysis rate.

[0144] The biodegradable polyester resin compositions according to the examples may also contain metal salts.

[0145] The metal salt may be present in a content of approximately 0.1 ppm to approximately 1000 ppm based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be present in a content of approximately 1 ppm to approximately 500 ppm based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be present in a content of approximately 1 ppm to approximately 100 ppm based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be present in a content of approximately 1 ppm to approximately 50 ppm based on the total weight of the biodegradable polyester resin composition according to the examples.

[0146] The metal salt may be selected from the group consisting of nitrates, sulfates, hydrochlorides, or carboxylates. The metal salt may be selected from the group consisting of titanium salts, silicon salts, sodium salts, calcium salts, potassium salts, magnesium salts, copper salts, iron salts, aluminum salts, or silver salts. The metal salt may be selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, or sodium nitrate.

[0147] The aforementioned metal salt may contain one or more elements selected from the group consisting of iron (Fe), magnesium (Mg), nickel (Ni), cobalt (Co), copper (Cu), palladium (Pd), zinc (Zn), vanadium (V), titanium (Ti), indium (In), manganese (Mn), silicon (Si), and tin (Sn).

[0148] Furthermore, the metal salt may be selected from the group consisting of acetate, nitrate, nitride, sulfide, sulfate, sulfoxide, hydrooxide, hydrate, chloride, chlorinate, and bromide.

[0149] Since the biodegradable polyester resin composition according to the examples contains the metal salt in the above-mentioned amounts, the hydrolysis rate and biodegradation rate can be appropriately adjusted.

[0150] The biodegradable polyester resin composition according to the examples may further contain a hydrolysis-resistant agent.

[0151] The hydrolysis-resistant agent may be selected from at least one silicon-based compound such as silane, silazane, or siloxane.

[0152] The hydrolysis-resistant agent may contain an alkoxysilane. The hydrolysis-resistant agent may contain trimethoxysilane and / or triethoxysilane. The hydrolysis-resistant agent may contain an alkoxysilane containing an epoxy group. The hydrolysis-resistant agent may contain at least one from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-Glycidoxypropyl methyldimethoxysilane, 3-Glycidoxypropyl trimethoxysilane, 3-Glycidoxypropyl methyldiethoxysilane, or 3-Glycidoxypropyl triethoxysilane.

[0153] The hydrolysis-resistant agent may be included in the biodegradable polyester resin composition according to the examples in a content of about 1 ppm to about 10,000 ppm. The hydrolysis-resistant agent may be included in the biodegradable polyester resin composition according to the examples in a content of about 1 ppm to about 1,000 ppm. The hydrolysis-resistant agent may be included in the biodegradable polyester resin composition according to the examples in a content of about 5 ppm to 500 ppm. The hydrolysis-resistant agent may be included in the biodegradable polyester resin composition according to the examples in a content of about 10 ppm to 300 ppm.

[0154] The hydrolysis-resistant agent may bond to the biodegradable polyester resin. The hydrolysis-resistant agent may chemically bond to the biodegradable polyester resin. The hydrolysis-resistant agent may chemically bond to the polymer contained in the biodegradable polyester resin. The hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin with each other.

[0155] The biodegradable polyester resin compositions according to the examples contain the hydrolysis-resistant agent within the range described above, and therefore may have appropriate hydrolysis resistance properties. In particular, the biodegradable polyester resins according to the examples contain the hydrolysis-resistant agent within the range described above, and therefore may have appropriate initial hydrolysis properties and improved biodegradability.

[0156] Therefore, the biodegradable polyester resin composition according to the examples may contain silicon. The biodegradable polyester resin composition according to the examples may contain silicon in a content of about 1 ppm to about 150 ppm. The biodegradable polyester resin composition according to the examples may contain silicon in a content of about 0.1 ppm to about 100 ppm. The biodegradable polyester resin composition according to the examples may contain silicon in a content of about 0.1 ppm to about 50 ppm. The biodegradable polyester resin composition according to the examples may contain silicon in a content of about 0.1 ppm to about 20 ppm.

[0157] Furthermore, the hydrolysis-resistant agent can also react with terminal carboxyl groups or unreacted carboxyl groups. As a result, the biodegradable polyester resin composition according to the examples may have a low acid value.

[0158] Furthermore, the hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin, thereby increasing the proportion of high molecular weight polymers in the biodegradable polyester resin composition according to the examples. This can improve the mechanical properties of the biodegradable polyester resin composition according to the examples.

[0159] The biodegradable polyester resin composition according to the examples may further contain a chain extender.

[0160] The chain extender may contain an isocyanate.

[0161] The chain extender may be selected from the group consisting of monofunctional isocyanates or polyfunctional isocyanates, with at least one selected from this group.

[0162] The chain extender may be selected from at least one of the group consisting of toylene 2,4-diisocyanate, toylene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate, and 2,4'-diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and methylenebis(4-isocyanatocyclohexane).

[0163] The chain extender may contain triisocyanate. The chain extender may also contain tri(4-isocyanatophenyl)methane.

[0164] The chain extender may contain an acrylic polymer. The acrylic polymer may contain acrylic groups. The acrylic groups may be bonded to the main chain as side chains. The acrylic polymer may contain epoxy groups. The epoxy groups may be bonded to the main chain as side chains.

[0165] The chain extender may include a styrene copolymer. The chain extender may also include a styrene glycidyl acrylate.

[0166] The chain extender may be chemically bonded to the biodegradable polyester resin. The chain extender may be chemically bonded to the polymer contained in the biodegradable polyester resin. The chain extender may be bonded to the ends of the polymer contained in the biodegradable polyester resin. Alternatively, the chain extender may be bonded to the ends of three polymers contained in the biodegradable polyester resin.

[0167] The chain extender may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.1 wt% to about 10 wt% based on the total composition. The chain extender may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.2 wt% to about 8 wt% based on the total composition. The chain extender may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.3 wt% to about 7 wt% based on the total composition.

[0168] The biodegradable polyester resin compositions according to the examples may have appropriate hydrolysis resistance and appropriate biodegradability when they contain the chain extender within the range described above.

[0169] Furthermore, the chain extender can react with terminal carboxyl groups or unreacted carboxyl groups. As a result, the biodegradable polyester resin composition according to the examples may have a low acid value.

[0170] Furthermore, the chain extender couples the polymer contained in the biodegradable polyester resin, thereby increasing the proportion of high molecular weight polymers in the biodegradable polyester resin composition according to the examples. This can improve the mechanical properties of the biodegradable polyester resin composition according to the examples.

[0171] The biodegradable polyester resin composition according to the examples may contain an oligomer. The molecular weight of the oligomer may be about 400 to about 1300.

[0172] The oligomer may be present in the biodegradable polyester resin composition according to the examples in an amount of approximately 3,000 ppm to approximately 30,000 ppm based on the overall resin composition. The oligomer may be present in the biodegradable polyester resin composition according to the examples in an amount of approximately 5,000 ppm to approximately 20,000 ppm based on the overall resin composition. The oligomer may be present in the biodegradable polyester resin composition according to the examples in an amount of approximately 5,000 ppm to approximately 15,000 ppm based on the overall resin composition. The oligomer may be present in the biodegradable polyester resin composition according to the examples in an amount of approximately 7,000 ppm to approximately 15,000 ppm based on the overall resin composition.

[0173] The oligomer may be a reaction product of at least two of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. The oligomer may also be a reaction product of 1,4-butanediol, terephthalic acid, and adipic acid.

[0174] The oligomer may include oligomers in which the molar ratio of the aliphatic dicarboxylic acid is even higher than the molar ratio of the aromatic dicarboxylic acid. Of the oligomers, the proportion of oligomers containing a relatively higher amount of the aliphatic dicarboxylic acid may be even higher than the proportion of oligomers containing a relatively higher amount of the aromatic dicarboxylic acid.

[0175] The oligomer can appropriately adjust the degree of hydrolysis of the biodegradable polyester resin composition according to the examples. The oligomer may also be a hydrolysis regulator that appropriately adjusts the degree of hydrolysis of the biodegradable polyester resin composition according to the examples.

[0176] Furthermore, the oligomer can appropriately adjust the degree of biodegradation of the biodegradable polyester resin composition according to the examples. The oligomer may also be a biodegradation regulator that appropriately adjusts the degree of biodegradation of the biodegradable polyester resin composition according to the examples.

[0177] The biodegradable polyester resin composition according to the examples may contain a heat stabilizer. The heat stabilizer may be a phosphorus-based heat stabilizer.

[0178] The heat stabilizer may be at least one selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentaamine, triethylphosphonoacetate, phosphoric acid, phosphorous acid, polyphosphoric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, or triphenyl phosphine.

[0179] Furthermore, the heat stabilizer may also be an antioxidant that has the function of preventing oxidation.

[0180] The content of the heat stabilizer may be approximately 3,000 ppm or less based on the total weight of the biodegradable polyester resin. The content of the heat stabilizer may be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the biodegradable polyester resin. By satisfying the above range for the content of the heat stabilizer, it is possible to control the degradation of the polymer due to high temperatures during the reaction process, reduce the end groups of the polymer, and improve the color. In addition, the heat stabilizer can suppress the activation of titanium-based catalysts and adjust the reaction rate.

[0181] The biodegradable polyester resin compositions according to the examples may contain an elongation improver. Examples of the elongation improver include oils such as paraffin oil, naphthenic oil, or aromatic oil, or adipates such as dibutyl adipate, diethylhexyl adipate, dioctyl adipate, or diisopropyl adipate.

[0182] The elongation improver may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.001 parts by weight to about 1 part by weight, based on 100 parts by weight of the biodegradable polyester resin. The elongation improver may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.01 parts by weight to about 1 part by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0183] The biodegradable polyester resin compositions according to the examples may also contain inorganic fillers. The inorganic fillers may be selected from at least one of the group consisting of calcium sulfate, barium sulfate, talc, talc powder, bentonite, kaolin, chalk powder, calcium carbonate, graphite, gypsum, electrically conductive carbon black, calcium chloride, iron oxide, aluminum oxide, potassium oxide, dolomite, silicon dioxide, wollastonite, titanium dioxide, silicates, mica, glass fibers, or mineral fibers.

[0184] With respect to the inorganic filler, the cumulative 50% particle size (D50), based on the volume in the particle size distribution obtained by laser diffraction, may be approximately 100 μm or less, approximately 85 μm or less, approximately 70 μm or less, approximately 50 μm or less, approximately 25 μm or less, approximately 10 μm or less, approximately 5 μm or less, approximately 3 μm or less, or approximately 1 μm or less.

[0185] Furthermore, the specific surface area of ​​the inorganic filler is approximately 100 m². 2 It may be 100 m² or more. For example, the specific surface area of ​​the inorganic filler is approximately 100 m². 2 / g or more, approximately 105m 2 / g or more or approximately 110m2 It may be more than / g.

[0186] The inorganic filler may be included in the biodegradable polyester resin composition according to the examples in an amount of about 3 to about 50 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The inorganic filler may be included in the biodegradable polyester resin composition according to the examples in an amount of about 5 to about 30 parts by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0187] The inorganic filler may be included in a content of approximately 3,000 ppm or less based on the total weight of the biodegradable polyester resin composition according to the examples. For example, the content of the inorganic filler may be approximately 3,000 ppm or less, approximately 1,500 ppm or less, approximately 1,200 ppm or less, approximately 800 ppm or less, or approximately 600 ppm or less based on the total weight of the biodegradable polyester resin composition according to the examples, or approximately 50 ppm or more, approximately 100 ppm or more, approximately 130 ppm or more, approximately 150 ppm or more, or approximately 180 ppm or more.

[0188] Since the biodegradable polyester resin composition according to the examples contains the inorganic filler in the above-mentioned amounts, it may have the mechanical properties, appropriate UV resistance, appropriate biodegradation rate, and appropriate hydrolysis rate of the biodegradable polyester resin composition according to the examples.

[0189] The biodegradable polyester resin composition according to the examples may further contain two types of biodegradable resins. The biodegradable polyester resin composition according to the examples may also be a composite resin composition containing two or more types of resins, fillers, and additives.

[0190] The two biodegradable resins mentioned above may be selected from at least one of the groups consisting of polybutylene azelate terephthalate (PBAzT), polybutylene sebacate terephthalate (PBSeT), polybutylene succinate terephthalate (PBST), polyhydroxyalkanoate (PHA), or polylactic acid (PLA).

[0191] The two types of biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 10 to about 100 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The two types of biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 10 to about 60 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The two types of biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 20 to about 50 parts by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0192] The two biodegradable resins can complement the mechanical, optical, and chemical properties of the biodegradable polyester resin. The biodegradable polyester resin composition according to the examples contains the two biodegradable resins in the above-mentioned amounts and may therefore have the mechanical properties, appropriate UV resistance, appropriate biodegradation rate, and appropriate hydrolysis rate of the biodegradable polyester resin composition according to the examples.

[0193] Furthermore, the number of carboxyl end groups in the biodegradable polyester resin composition according to the examples may be about 50 eq / ton or less. For example, the number of carboxyl end groups in the biodegradable polyester resin according to the examples may be about 50 eq / ton or less, about 48 eq / ton or less, about 45 eq / ton or less, or about 42 eq / ton or less. By adjusting the number of carboxyl end groups within the above range, when the biodegradable polyester resin composition according to the examples is extruded to form a molded product, degradation can be prevented and improved mechanical properties can be achieved.

[0194] Furthermore, the intrinsic viscosity (IV) of the biodegradable polyester resin composition according to the examples may be about 0.9 dl / g or higher. The intrinsic viscosity of other biodegradable polyester resin compositions in the examples may be about 0.95 dl / g or higher, about 1.0 dl / g or higher, about 1.1 dl / g or higher, about 1.2 dl / g or higher, or about 1.3 dl / g or higher. The intrinsic viscosity of other biodegradable polyester resin compositions in the examples may be about 0.95 dl / g to about 1.7 dl / g. The intrinsic viscosity of other biodegradable polyester resin compositions in the examples may be about 1.3 dl / g to about 1.7 dl / g. The intrinsic viscosity of other biodegradable polyester resin compositions in the examples may be about 1.4 dl / g to about 1.7 dl / g.

[0195] The process for producing the biodegradable polyester resin composition according to the examples is as follows:

[0196] Referring to Figure 1, the biodegradable polyester resin manufacturing apparatus includes a slurry stirrer 100, an esterification reaction section 200, a condensation polymerization reaction section 300, a post-processing section 400, a first recovery section 510, and a second recovery section 520.

[0197] The method for producing the biodegradable polyester resin includes the step of producing a slurry containing the diol and the aromatic dicarboxylic acid.

[0198] The step of producing the slurry includes a step of mixing and treating the diol and the aromatic dicarboxylic acid. That is, the step of producing the slurry is a pretreatment step before the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid to form a slurry. In this case, the diol may include a biomass-based diol component. The temperature of the slurry of the diol and the aromatic dicarboxylic acid may be about 5°C to about 15°C higher than the melting point of the diol. For example, if the diol is 1,4-butanediol, the temperature of the slurry may be about 35°C to about 45°C.

[0199] The diol and the aromatic dicarboxylic acid can be added to the slurry stirrer 100 and stirred to produce the slurry.

[0200] By pre-treating the mixture of the diol and the aromatic dicarboxylic acid to form a slurry, the diol and aromatic dicarboxylic acid can be reacted uniformly, and the esterification reaction can be accelerated, thereby increasing the reaction efficiency.

[0201] In particular, when aromatic dicarboxylic acids, such as terephthalic acid, are perfectly crystalline and in powder form, their solubility in the diol can be very low, making homogeneous reactions difficult. Therefore, the slurry pretreatment process can play a very important role in increasing reaction efficiency by providing biodegradable polyester resins, sheets, films, and molded articles with excellent physical properties as embodied in the present invention.

[0202] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid is perfectly crystalline, has no melting point, is a white crystal that sublimes at around 300°C at atmospheric pressure, and has very low solubility in the diol, making homogeneous reactions difficult. Therefore, if a pretreatment step is performed before the esterification reaction, the reaction with the diol occurs within the solid matrix of terephthalic acid, increasing the surface area and inducing a homogeneous reaction.

[0203] Furthermore, if the aromatic dicarboxylic acid is dimethyl terephthalic acid, the pretreatment process allows the dimethyl terephthalic acid to be molten at approximately 142°C to 170°C and reacted with the diol, thereby enabling a faster and more efficient esterification reaction.

[0204] On the other hand, in the pretreatment step for producing the slurry, the structure and physical properties of the biodegradable polyester resin may differ depending on the particle size, particle size distribution, and pretreatment reaction conditions of the aromatic dicarboxylic acid.

[0205] For example, the aromatic dicarboxylic acid includes terephthalic acid, wherein the terephthalic acid has an average particle size (D50) of 10 μm to 400 μm as measured by a Microtrac S3500 particle size analyzer in the particle size distribution (PSD), and the standard deviation of the average particle size (D50) is 100 or less. The standard deviation means the square root of the variance. The average particle size (D50) of the terephthalic acid may be 20 μm to 200 μm, for example, 30 μm to 180 μm, or for example, 100 μm to 160 μm. When the average particle size (D50) of the terephthalic acid satisfies the above range, it may be even more advantageous in terms of improved solubility in the diol and reaction rate.

[0206] In the aforementioned pretreatment step, the diol and the aromatic dicarboxylic acid can be mixed and then introduced into the slurry agitator 100 (tank).

[0207] For example, the slurry agitator 100 may be even more advantageous in achieving an efficient stirring effect if its lowest part is of the anchor type, the height to the agitator is 20 mm or more, and it is equipped with two or more rotating blades.

[0208] For example, the slurry agitator 100 may have a height of 20 mm or more from the agitator, meaning that there is almost no contact between the reactor and the bottom of the agitator. In this case, slurry can be obtained without sedimentation. If the pattern, shape, and rotor blades of the agitator do not satisfy the above conditions, when the diol and aromatic dicarboxylic acid are initially mixed, the aromatic dicarboxylic acid may settle at the bottom, and in this case, phase separation may occur.

[0209] The pretreatment step for producing the first slurry may include a step of mixing the diol and the aromatic dicarboxylic acid and stirring them at approximately 30°C to approximately 100°C at approximately 50 rpm to approximately 200 rpm for 10 minutes or more, or 10 minutes to 200 minutes.

[0210] The aforementioned diol may have the same characteristics as described above.

[0211] The diol can be added all at once or in portions. For example, the diol can be added separately when mixed with an aromatic dicarboxylic acid and when mixed with an aliphatic dicarboxylic acid.

[0212] The aforementioned aromatic dicarboxylic acid may have the same characteristics as described above.

[0213] In the pretreatment step for producing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid may be about 0.8:1 to about 2:1. In the pretreatment step for producing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid may be about 1.1:1 to about 1.5:1. In the pretreatment step for producing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid may be about 1.2:1 to about 1.5:1.

[0214] If the diol is added in an even larger amount than the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be easily dispersed.

[0215] Furthermore, additives may be added to the slurry. The nanocellulose and / or the metal salt may be added to the slurry in the form of a dispersion or solution.

[0216] The method for producing the biodegradable polyester resin involves mixing a diol and an aromatic dicarboxylic acid, pre-treating the mixture to obtain a slurry, carrying out an esterification reaction to obtain a prepolymer, and then carrying out a condensation polymerization reaction on the prepolymer. Through this embodiment of the present invention, the desired structure and physical properties of the biodegradable polyester resin can be efficiently achieved.

[0217] The method for producing the biodegradable polyester resin includes a step of producing a prepolymer by esterifying the slurry and the aliphatic dicarboxylic acid. The slurry and the aliphatic dicarboxylic acid can be reacted in the esterification reaction section.

[0218] In the esterification reaction, the reaction time can be shortened by using the slurry. For example, the slurry obtained in the pretreatment step can shorten the reaction time of the esterification reaction by 1.5 times or more.

[0219] The esterification reaction can be carried out at least twice. The esterification reaction can form a prepolymer that will be introduced into the condensation polymerization step.

[0220] In one embodiment, the esterification reaction can be carried out in one step after adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid, to the slurry. That is, the slurry can be put into the esterification reactor, and the esterification reaction can be carried out by adding either the aliphatic dicarboxylic acid alone, or the aliphatic dicarboxylic acid and the diol to the esterification reactor.

[0221] The diol and the aliphatic dicarboxylic acid may be in slurry form and may be added to a slurry containing the aromatic dicarboxylic acid.

[0222] The average particle size (D50) of the aliphatic dicarboxylic acid in the slurry of the diol and the aliphatic dicarboxylic acid may be about 50 μm to about 150 μm. The average particle size (D50) of the aliphatic dicarboxylic acid in the slurry of the diol and the aliphatic dicarboxylic acid may be about 60 μm to about 120 μm.

[0223] In the esterification reaction, the total number of moles of diol added may be about 1.0 to about 1.8 relative to the total number of moles of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. In the esterification reaction, the total number of moles of diol added may be about 1.1 to about 1.6 relative to the total number of moles of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0224] Furthermore, the temperature of the slurry of the diol and the aliphatic dicarboxylic acid may be about 5°C to 15°C higher than the melting point of the diol.

[0225] Furthermore, the various additives, such as the nanocellulose, may also be added to the slurry of the diol and the aliphatic dicarboxylic acid.

[0226] The esterification reaction can be carried out at a temperature of approximately 250°C or lower for approximately 0.5 hours to approximately 5 hours. Specifically, the esterification reaction can be carried out at a temperature of approximately 180°C to approximately 250°C, approximately 185°C to approximately 240°C, or approximately 200°C to approximately 240°C, under atmospheric pressure or reduced pressure until the by-product water theoretically accounts for 95%. For example, the esterification reaction can be carried out for 0.5 hours to 5.5 hours, 0.5 hours to 4.5 hours, or 1 hour to 4 hours, but is not limited to these.

[0227] In one embodiment, the first esterification reaction can be carried out by mixing the polycarbonate diol and / or the polyether polyol with the slurry. Alternatively, the polycarbonate diol and / or the polyether polyol can be added to the second esterification reaction.

[0228] Furthermore, after the first esterification reaction, a mixture of the aliphatic dicarboxylic acid and the diol can be added to the esterification reaction chamber to carry out a second esterification reaction together with the first esterification reaction product. In addition, the polycarbonate diol and / or the polyether polyol can be added to the second esterification reaction.

[0229] The first esterification reaction can be carried out at a temperature of 250°C or lower for 1.25 to 4 hours. Specifically, the first esterification reaction can be carried out at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C under atmospheric or reduced pressure until the by-product water theoretically accounts for 95%. For example, the first esterification reaction can be carried out for 1.25 to 4 hours, 1.25 to 3.5 hours, or 2.5 to 3 hours, but is not limited to these.

[0230] The second esterification reaction can be carried out at approximately 250°C or below for 0.25 to 3.5 hours. Specifically, the second esterification reaction can be carried out at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C under atmospheric or reduced pressure until the by-product water theoretically accounts for 95%. For example, the second esterification reaction can be carried out for 0.5 to 3 hours, 1 to 2.5 hours, or 1.5 to 2.5 hours, but is not limited to these.

[0231] In the first and second esterification reactions, the reaction temperature, reaction time, and the content of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid added may be adjusted to control the ratio of the first and second blocks. Furthermore, when the esterification reaction is carried out separately as a first and second esterification reaction, the overall esterification reaction can be precisely controlled. This can improve the reaction stability and reaction uniformity of the esterification reaction.

[0232] Furthermore, the branching agent may be added in the second esterification reaction. That is, the aliphatic dicarboxylic acid, the mixture of the diol, the branching agent, and the first esterification reaction product may react to form the prepolymer. The characteristics and content of the branching agent may be the same as described above.

[0233] A prepolymer can be formed by the esterification reaction described above.

[0234] The average water molecular weight of the prepolymer may be approximately 500 to approximately 10,000 g / mol. For example, the average water molecular weight of the prepolymer may be approximately 500 to approximately 8,500 g / mol, approximately 500 to approximately 8,000 g / mol, approximately 500 to approximately 7,000 g / mol, approximately 500 g / mol to approximately 5,000 g / mol, or approximately 800 g / mol to approximately 4,000 g / mol. By having the average water molecular weight of the prepolymer satisfy the above range, the molecular weight of the polymer in the condensation polymerization reaction can be efficiently increased.

[0235] The water-average molecular weight can be measured using gel permeation chromatography (GPC). Specifically, the data calculated by gel permeation chromatography includes various parameters such as Mn, Mw, and Mp, and the molecular weight can be measured using the water-average molecular weight (Mn) as the reference.

[0236] The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, or the metal salt may be added together with the slurry before the esterification reaction. The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, and / or the metal salt may be added to the esterification reaction section 200 during the esterification reaction. The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, and / or the metal salt may be added to the esterification reaction product after the esterification reaction. Furthermore, the reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, and / or the metal salt may be added together with the aliphatic dicarboxylic acid. Furthermore, the reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, and / or the metal salt may be added to the esterification reaction section 200 after the first esterification reaction and before the second esterification reaction.

[0237] Since the reinforcing material and / or the metal salt are introduced into the esterification reaction, the reinforcing material and / or the metal salt can be uniformly dispersed within the biodegradable polyester resin.

[0238] The reinforcing material may have the same characteristics as described above. In particular, nanocellulose can be used as the reinforcing material.

[0239] The nanocellulose may be pretreated by a bead mill, by ultrasound, or by high-speed dispersion at approximately 1000 rpm to 1500 rpm before being introduced. Specifically, the nanocellulose may be water-dispersed nanocellulose that has been pretreated by a bead mill or by ultrasound.

[0240] First, the bead mill pretreatment can be performed using a wet milling device, either a vertical mill or a horizontal mill. A horizontal mill is preferable because it can fill the chamber with a larger quantity of beads, reduces uneven wear on the machine, reduces bead wear, and facilitates maintenance, but it is not limited to this.

[0241] The bead mill pretreatment can be carried out using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0242] Specifically, the bead mill pretreatment can be carried out using beads having a diameter of approximately 0.3 mm to approximately 1 mm. For example, the diameter of the beads may be approximately 0.3 mm to approximately 0.9 mm, approximately 0.4 mm to approximately 0.8 mm, approximately 0.45 mm to approximately 0.7 mm, or approximately 0.45 mm to approximately 0.6 mm.

[0243] By ensuring the bead diameter falls within the above range, the dispersibility of nanocellulose can be further improved. If the bead diameter exceeds this range, the average particle size and particle size deviation of the nanocellulose may increase, potentially leading to decreased dispersibility.

[0244] Furthermore, the bead mill pretreatment is preferable in that it uses beads with a specific gravity higher than that of nanocellulose, in order to transfer sufficient energy. For example, the beads may be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide, which have a specific gravity higher than that of water-dispersed nanocellulose. Zirconium beads with a specific gravity four times or more higher than that of water-dispersed nanocellulose are preferred, but are not limited to this.

[0245] Furthermore, the ultrasonic pretreatment is a method of physically sealing or pulverizing nanoparticles by generating waves through the emission of 20 kHz ultrasonic waves into a solution.

[0246] The ultrasonic pretreatment can be performed at an output of 30,000 J / s or less for less than 30 minutes. For example, the ultrasonic pretreatment can be performed at an output of 25,000 J / s or less or 22,000 J / s or less for 25 minutes or less, 20 minutes or less, or 18 minutes or less. By keeping the output and execution time within the above range, the effect of the ultrasonic pretreatment, i.e., the improvement in dispersibility, can be maximized. If the output exceeds the above range, the nanoparticles may re-aggregate, resulting in lower dispersibility.

[0247] The nanocellulose in the embodiment may be pre-treated with a bead mill or ultrasonically. Alternatively, the nanocellulose in the embodiment may be pre-treated with both a bead mill and ultrasonically. In this case, it is preferable to perform the ultrasonic pre-treatment after the bead mill pre-treatment in order to prevent re-aggregation and improve dispersibility.

[0248] Because the nanocellulose contains ionically bonded metals, it exhibits very high dispersibility in water. Furthermore, the bead mill pretreatment and / or ultrasonic pretreatment yield an aqueous dispersion of the nanocellulose with a very high degree of dispersion. The content of the nanocellulose in the aqueous dispersion may be about 1 wt% to about 50 wt%.

[0249] A titanium-based catalyst and / or a germanium-based catalyst can be used in the esterification reaction. Specifically, the titanium-based catalyst and / or the germanium-based catalyst can be added to the slurry to carry out the esterification reaction.

[0250] Furthermore, the titanium-based catalyst and / or the germanium-based catalyst may be added to the slurry before the first esterification reaction, and the titanium-based catalyst and / or the germanium-based catalyst may be further added to the product of the first esterification reaction.

[0251] The biodegradable polyester resin may contain one or more titanium-based catalysts selected from the group consisting of titanium isopropoxide, antimony trioxide, dibutyltin oxaside, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, antimony acetate, calcium acetate, and magnesium acetate, or one or more germanium-based catalysts selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethylgermanium, tetraethylgermanium, and germanium sulfide.

[0252] Furthermore, the content of the catalyst may be approximately 50 ppm to 2000 ppm, based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. For example, it may contain titanium-based or germanium-based catalysts in amounts of approximately 60 ppm to 1600 ppm, approximately 70 ppm to 1400 ppm, approximately 80 ppm to 1200 ppm, or approximately 100 ppm to 1100 ppm. By satisfying the above range for the catalyst content, the physical properties can be further improved.

[0253] Furthermore, the heat stabilizer may be added together with the slurry before the esterification reaction. The heat stabilizer may be added to the esterification reaction section 200 during the esterification reaction. The heat stabilizer may be added to the esterification reaction product after the esterification reaction. Furthermore, the heat stabilizer may be added together with the aliphatic dicarboxylic acid. Furthermore, the heat stabilizer may be added to the esterification reaction section 200 after the first esterification reaction and before the second esterification reaction.

[0254] The characteristics of the heat stabilizer may be the same as those described above.

[0255] The content of the heat stabilizer may be 3,000 ppm or less based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Specifically, the content of the heat stabilizer may be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By satisfying the above range for the content of the heat stabilizer, it is possible to control the degradation of the polymer due to high temperatures during the reaction process, reduce the end groups of the polymer, and improve the color.

[0256] After the esterification reaction is completed, one or more additives selected from the group consisting of silica, potassium, or magnesium, and color correctors such as cobalt acetate may be further added to the esterification reaction product. That is, after the esterification reaction is completed, the additives and / or color correctors may be added and stabilized before the polymerization condensation reaction can be carried out. The additives and / or color correctors may be added after the esterification reaction is completed and introduced into the polymerization condensation reaction section 300 together with the prepolymer. This allows the additives and / or color correctors to be uniformly dispersed in the biodegradable polyester resin.

[0257] Furthermore, the inorganic filler may be added to the esterification reaction product after the esterification reaction is completed. That is, after the esterification reaction is completed, the inorganic filler can be added and stabilized, and then the polymerization condensation reaction can be carried out. The characteristics of the inorganic filler are as described above. The inorganic filler can be added to the polymerization condensation reaction section 300 together with the prepolymer to carry out the polymerization condensation step. In this way, the inorganic filler can be uniformly dispersed in the biodegradable polyester resin.

[0258] Furthermore, the first recovery unit 510 recovers reaction by-products such as water from the esterification reaction unit 200. The first recovery unit 510 can recover by-products generated in the esterification reaction by applying vacuum pressure or refluxing to the esterification reaction unit 200.

[0259] The method for producing the biodegradable polyester resin includes a step of undergoing a condensation polymerization reaction of the prepolymer. The condensation polymerization reaction can be carried out as follows.

[0260] The prepolymer is introduced into the polymerization condensation reaction section 300. Alternatively, at least one of the reinforcing material, the heat stabilizer, the color corrector, the inorganic filler, the metal salt, or other additives may be introduced into the polymerization condensation reaction section 300 together with the prepolymer.

[0261] Subsequently, the condensation polymerization reaction can be carried out at approximately 180°C to approximately 280°C and at approximately 10 torr or less for approximately 1 to 5 hours. For example, the condensation polymerization reaction can be carried out at approximately 190°C to approximately 270°C, approximately 210°C to approximately 260°C, or approximately 230°C to approximately 255°C, at approximately 0.9 torr or less, approximately 0.7 torr or less, approximately 0.2 torr to approximately 10 torr, approximately 0.2 torr to approximately 0.9 torr, or approximately 0.2 torr to approximately 0.6 torr, and can be carried out for approximately 1.5 hours to approximately 5 hours, approximately 2 hours to approximately 4.5 hours, or approximately 2 hours to approximately 4 hours.

[0262] Furthermore, the condensation polymerization reaction may include primary and secondary condensation polymerization.

[0263] For example, the primary condensation polymerization can be carried out at a temperature of approximately 260°C or lower, approximately 250°C or lower, approximately 215°C to approximately 250°C, approximately 215°C to approximately 245°C, or approximately 230°C to approximately 245°C, for a duration of approximately 1 torr to approximately 200 torr, approximately 2 torr to approximately 100 torr, approximately 4 torr to approximately 50 torr, approximately 5 torr to approximately 45 torr, or approximately 8 torr to approximately 32 torr, for a duration of approximately 0.5 hours to approximately 3.5 hours, approximately 0.5 hours to approximately 3.0 hours, or approximately 0.5 hours to approximately 2.8 hours.

[0264] Furthermore, the secondary polymerization can be carried out at approximately 220°C to approximately 265°C, approximately 230°C to approximately 260°C, or approximately 235°C to approximately 255°C, with a condensation rate of approximately 1 torr or less, approximately 0.8 torr or less, approximately 0.6 torr or less, approximately 0.1 torr to approximately 1 torr, approximately 0.2 torr to approximately 0.8 torr, or approximately 0.2 torr to approximately 0.6 torr, for approximately 0.5 hours to approximately 4 hours, approximately 1 hour to approximately 3.5 hours, or approximately 1.5 hours to approximately 3.5 hours.

[0265] Furthermore, a titanium-based catalyst or a germanium-based catalyst may be added to the prepolymer before the condensation polymerization reaction. Also, before the condensation polymerization reaction, one or more additives selected from the group consisting of silica, potassium, or magnesium; amine-based stabilizers such as trimethylphosphate, triphenylphosphate, trimethylphosphine, phosphoric acid, phosphorous acid, or tetraethylenepentaamine; and polymerization catalysts such as antimontrioxide, antimony trioxide, or tetrabutyl titanate may be added to the prepolymer.

[0266] The average water molecular weight of the polymer may be about 30,000 g / mol or more. For example, the average water molecular weight of the polymer may be about 33,000 g / mol or more, about 35,000 g / mol or more, or about 40,000 g / mol to about 90,000 g / mol. By satisfying the above range for the average water molecular weight of the polymer, the physical properties, impact resistance, durability, and moldability can be further improved.

[0267] Furthermore, the second recovery unit 520 recovers reaction by-products such as water from the polymerization reaction unit 300. The second recovery unit 520 can also recover by-products generated in the polymerization reaction by applying vacuum pressure to the polymerization reaction unit 300.

[0268] The second recovery unit 520 can apply a vacuum pressure of approximately 0.1 torr to approximately 1 torr inside the polymerization reaction unit 300. The second recovery unit 520 can apply a vacuum pressure of approximately 0.1 torr to approximately 0.9 torr inside the polymerization reaction unit 300.

[0269] Subsequently, the hydrolysis-resistant agent and / or the chain extender are added to the polymer. The polymer, hydrolysis-resistant agent and chain extender are then uniformly mixed and maintained at a temperature of approximately 200°C to 260°C for approximately 1 to 15 minutes. This causes the polymer to react with the hydrolysis-resistant agent and / or the chain extender.

[0270] In contrast, the hydrolysis-resistant agent and / or the chain extender can be added to the polymerization condensation reaction section 300 by a static mixer and react with the polymer. The reaction temperature of the hydrolysis-resistant agent and / or the chain extender in the polymerization condensation reaction section 300 may be about 200°C to about 260°C. The reaction time of the hydrolysis-resistant agent and / or the chain extender in the polymerization condensation reaction section 300 may be about 1 minute to about 15 minutes.

[0271] The chain extender may have the same characteristics as described above.

[0272] As a result, the biodegradable polyester resin compositions according to the examples may have an appropriate degree of hydrolysis and a high degree of biodegradation.

[0273] Subsequently, pellets can be produced from the polymer.

[0274] Specifically, the polymer can be cooled to approximately 15°C or below, approximately 10°C or below, or approximately 6°C or below, and then the cooled polymer can be cut to produce pellets. Alternatively, the polymer can be cut at a temperature of approximately 40°C to approximately 60°C.

[0275] The aforementioned cutting step can be performed using any pellet cutting machine used in this industry without limitation, and the pellets may have various shapes. The pellet cutting method may include an underwater cutting method or a strand cutting method.

[0276] The pellets can undergo further post-processing steps. The pellets can be fed into the post-processing unit 400 to perform the post-processing steps.

[0277] The post-treatment process can be carried out within the post-treatment unit 400. The pellets are introduced into the post-treatment unit 400. Thereafter, the post-treatment unit 400 can melt the introduced pellets by frictional heat and re-extrude them. That is, the post-treatment unit 400 may include a pressing machine such as a twin-screw extruder or the like.

[0278] The temperature of the post-treatment process may be about 230°C to about 270°C. The temperature of the post-treatment process may be about 230°C to about 260°C. The temperature of the post-treatment process may be about 240°C to about 265°C. The temperature of the post-treatment process may be about 240°C to about 260°C.

[0279] The time of the post-treatment process may be about 30 seconds to about 3 minutes. The time of the post-treatment process may be about 50 seconds to about 2 minutes. The time of the post-treatment process may be about 1 minute to about 2 minutes.

[0280] Thereafter, the resin extruded by the pressing machine can be cooled, cut, and processed into post-treated pellets. That is, the resin extruded from the pressing machine can be reprocessed into pellets by the aforementioned cutting step.

[0281] The crystallinity of the pellets can be improved in the post-treatment process. Also, the content of the residues contained in the pellets can be adjusted in the post-treatment process. In particular, the content of the oligomers contained in the pellets can be adjusted by the post-treatment process. The content of the residual solvent contained in the pellets can be adjusted by the post-treatment process.

[0282] Thereby, the post-treatment process can appropriately adjust the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable polyester resin.

[0283] After the pellets are manufactured, the biodegradable polyester resin can be compounded with the two types of biodegradable resins. In addition, at least one of the inorganic filler, the light stabilizer, the color corrector, or the other additives can be compounded with the biodegradable polyester resin and the two types of biodegradable resins.

[0284] The compounding process may be as follows:

[0285] The biodegradable polyester resin and the two types of biodegradable resins are mixed with at least one of the inorganic filler, the heat stabilizer, the color corrector, the metal salt, or the other additives, and then fed into a press. The mixed biodegradable polyester resin composition is melted in the press at a temperature of about 120°C to about 260°C and mixed with each other. The molten and mixed biodegradable polyester resin composition is then extruded, cooled, cut, and re-pelletized. Through this process, the biodegradable polyester resin composition according to the example can be produced by compounding it with the two types of biodegradable resins.

[0286] In contrast, the inorganic filler, the heat stabilizer, the color corrector, the metal salt, and the other additives can be added during the polymerization process of the biodegradable polyester resin.

[0287] A biodegradable polyester film can be manufactured using the biodegradable polyester resin described in the examples.

[0288] The thickness of the biodegradable polyester film may be approximately 5 μm to approximately 300 μm. For example, the thickness of the biodegradable polyester film may be approximately 5 μm to approximately 180 μm, approximately 5 μm to approximately 160 μm, approximately 10 μm to approximately 150 μm, approximately 15 μm to approximately 130 μm, approximately 20 μm to approximately 100 μm, approximately 25 μm to approximately 80 μm, or approximately 25 μm to approximately 60 μm.

[0289] The biodegradable polyester film according to the examples may have substantially the same degree of hydrolysis and biodegradation as the biodegradable polyester resin composition described above.

[0290] On the other hand, the biodegradable polyester film can be manufactured using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0291] Specifically, the method for producing the biodegradable polyester film may include the steps of producing a biodegradable resin composition according to the examples, and drying and melt-extruding the biodegradable resin composition.

[0292] In the step of drying and melt-extruding the biodegradable resin composition, the drying can be carried out at approximately 60°C to approximately 100°C for approximately 2 to approximately 12 hours. Specifically, the drying can be carried out at approximately 65°C to approximately 95°C, approximately 70°C to approximately 90°C, or approximately 75°C to approximately 85°C for approximately 3 to approximately 12 hours, or approximately 4 to approximately 10 hours. By ensuring that the pellet drying process conditions meet the above range, the quality of the manufactured biodegradable polyester film or molded product can be further improved.

[0293] In the drying and melt extrusion steps, the melt extrusion can be carried out at a temperature of approximately 270°C or lower. For example, the melt extrusion can be carried out at a temperature of approximately 265°C or lower, approximately 260°C or lower, approximately 255°C or lower, approximately 150°C to approximately 270°C, approximately 150°C to approximately 255°C, or approximately 150°C to approximately 240°C. The melt extrusion can be carried out in a blown film process. The melt extrusion can be carried out using a T-die.

[0294] Furthermore, the film manufacturing process may also be a calendering process.

[0295] Biodegradable polyester molded products Biodegradable polyester molded articles can be manufactured using the aforementioned biodegradable polyester resin.

[0296] Specifically, the molded article can be manufactured by molding the biodegradable polyester resin composition using methods known in the industry, such as extrusion or injection molding. The molded article may be, but is not limited to, an injection-molded article, an extruded article, a thin-film molded article, a blow-molded or blow-molded article, a 3D filament, or an interior building material.

[0297] For example, the molded product may be in the form of a film or sheet used in agricultural mulching films, disposable gloves, disposable films, disposable envelopes, food packaging materials, and weight-based garbage bags, or it may be in the form of fibers used in woven fabrics, knitted fabrics, nonwoven fabrics, ropes, etc. Also, as shown in Figure 2, the molded product may be in the form of a disposable container used for food packaging such as bento boxes. Furthermore, the molded product may be in the form of various shapes such as disposable straws, spoons and chopsticks, eating boards, and forks.

[0298] In particular, since the molded product can be formed from the biodegradable polyester resin, which can improve physical properties such as impact absorption energy and hardness, as well as impact resistance and durability, it can exhibit excellent properties when applied to packaging materials for products stored and transported at low temperatures, automotive interior materials requiring durability, garbage bags, mulching films, and disposable products.

[0299] The physical properties of the biodegradable film and the biodegradable molded article can be measured in a manner similar to that of the biodegradable polyester resin composition according to the examples.

[0300] The biodegradable polyester resin composition according to the embodiment may have a molecular weight reduction rate of about 80% or more. The biodegradable polyester resin composition according to the embodiment may have a molecular weight reduction rate of about 85% or more. The biodegradable polyester resin composition according to the embodiment may have a molecular weight reduction rate of about 90% or more. In order to measure the molecular weight reduction rate, the biodegradable polyester resin composition was mixed with compost, and a biodegradation acceleration test was carried out at a temperature of 60 °C and a humidity of 90%. Using gel permeation chromatography (GPC), the number average molecular weight after 63 days was measured in the polyester resin compositions of the examples and comparative examples. The value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period by the initial number average molecular weight was derived as the molecular weight reduction rate.

[0301] The molecular weight reduction rate can be derived by the following formula 1.

[0302] [Formula 1] JPEG0007894469000008.jpg14151

[0303] Here, the biodegradable polyester resin composition according to the embodiment is mixed with compost and undergoes a biodegradation acceleration test at a temperature of 60 °C and a humidity of 90% for about 63 days. Before the biodegradation acceleration test is carried out, the initial number average molecular weight of the biodegradable polyester resin composition and the number average molecular weight 63 days after the biodegradable polyester resin composition has undergone a 63-day biodegradation acceleration test are measured by gel permeation chromatography (GPC).

[0304] The molecular weight reduction rate was derived as the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period, for example, 63 days, by the initial number average molecular weight.

[0305] Also, the compost may contain about 40 wt% pig manure, about 15 wt% chicken manure, about 37 wt% large sawdust, about 5 wt% zeolite, and about 3 wt% microbial preparation.

[0306] Furthermore, the manufacturer of the compost may be Taeheung F&G, and the product name of the compost may be Chisei-do (by-product fertilizer, Grade 1 compost).

[0307] Furthermore, when the rate of decrease in molecular weight is measured, the biodegradable polyester resin composition according to the example is manufactured into a sheet having a thickness of approximately 300 μm. Subsequently, the manufactured sheet is cut into pieces approximately 3 cm x 3 cm in size to produce flakes. The flakes are mixed with the compost, and the biodegradation acceleration test is performed.

[0308] The biodegradable polyester film according to the examples may have the molecular weight reduction rate described above. Similarly, the biodegradable polyester film according to the examples can be cut into pieces approximately 3 cm x 3 cm in size to produce flakes. These flakes can then be mixed with the compost to perform the accelerated biodegradation test.

[0309] The biodegradable polyester resin composition according to the examples may have a biodegradability of about 80% or more. The biodegradable polyester resin composition according to the examples may have a biodegradability of about 85% or more. The biodegradable polyester resin composition according to the examples may have a biodegradability of about 90% or more. The biodegradability can be derived by the following formula 2.

[0310] [Formula 2] JPEG0007894469000009.jpg13151

[0311] The degree of biodegradation of the biodegradable polyester resin composition according to the examples can be measured based on the amount of carbon dioxide generated according to KS M3100-1. Specifically, an inoculum container containing only compost produced at a composting plant is prepared, and a test container is prepared in which flakes of the biodegradable polyester resin composition at a concentration of 5% by weight of the dry weight of the compost are added to the compost. Then, the compost and flakes are cultured for 180 days under conditions of a temperature of 58±2℃, a moisture content of 50%, and an oxygen concentration of 6% or higher, and the carbon dioxide generated in each container is collected, and the amount of carbon dioxide generated in each container is measured by titration with an aqueous phenolphthalein solution. As shown in Equation 2 above, the degree of biodegradation was derived as the ratio of carbon dioxide generated by the biodegradable polyester resin composition to the theoretical amount of carbon dioxide generated.

[0312] When the degree of biodegradation is measured, the flakes of the biodegradable polyester resin composition can be manufactured in substantially the same manner as the flakes when the rate of decrease in molecular weight is measured.

[0313] The biodegradable polyester film according to the example may have the degree of biodegradation described above. Similarly, the biodegradable polyester film according to the example can be cut into pieces approximately 3 cm x 3 cm in size to produce flakes. These flakes can be mixed with the compost to perform the biodegradation test.

[0314] The degree of hydrolysis of the biodegradable polyester resin composition according to the examples can be measured by the following method.

[0315] To measure the degree of hydrolysis, the biodegradable resin composition according to the example was immersed in water (100% RH) at 80°C, and then an accelerated hydrolysis test was performed. After a certain period of time, the number-average molecular weight of the biodegradable polyester resin composition according to the example was measured using gel permeation chromatography (GPC). The degree of hydrolysis was derived by dividing the difference between the initial number-average molecular weight and the number-average molecular weight after hydrolysis for a certain period by the initial number-average molecular weight.

[0316] The degree of hydrolysis may be expressed by the following formula 3.

[0317] [Formula 3] JPEG0007894469000010.jpg14148

[0318] In this example, the biodegradable polyester resin composition is immersed in water at 80°C and then subjected to an accelerated hydrolysis test for a certain period. Before the accelerated hydrolysis test, the initial number-average molecular weight of the biodegradable polyester resin composition, and the number-average molecular weight of the biodegradable polyester resin composition after hydrolysis following the accelerated hydrolysis test for a certain period, are measured by gel permeation chromatography (GPC).

[0319] The degree of hydrolysis was derived by dividing the difference between the initial number-average molecular weight and the number-average molecular weight after hydrolysis for a certain period by the initial number-average molecular weight.

[0320] Furthermore, when the degree of hydrolysis is measured, the biodegradable polyester resin composition according to the example is manufactured into a sheet having a thickness of approximately 300 μm. The manufactured sheet is then cut into pieces approximately 3 cm x 3 cm in size to produce flakes. The flakes can be immersed in the hot water to perform the hydrolysis acceleration test.

[0321] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after one week may be about 40% to about 65%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after one week may be about 45% to about 63%.

[0322] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 2 weeks may be about 80% to about 93%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 2 weeks may be about 85% to about 92%.

[0323] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 3 weeks may be about 90% to about 97%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 3 weeks may be about 91% to about 96%.

[0324] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 4 weeks may be about 92% to about 99%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 4 weeks may be about 93% to about 97%.

[0325] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 6 weeks may be approximately 94% or higher. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 6 weeks may be approximately 95% or higher.

[0326] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 9 weeks may be about 95% or more. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after 9 weeks may be about 96% or more.

[0327] The biodegradable polyester resin composition according to the examples may have a wet hardness reduction rate. The wet hardness reduction rate is the value obtained by dividing the difference between the initial hardness before immersion and the wet hardness after immersion by the initial hardness, after the biodegradable polyester resin composition has been immersed in water at a certain temperature for a certain period of time.

[0328] The aforementioned wet hardness reduction rate can be derived by the following formula 4.

[0329] [Equation 4] JPEG0007894469000011.jpg15128

[0330] In the biodegradable polyester resin composition according to the examples, the wet hardness reduction rate after immersion at a temperature of approximately 30°C for approximately 24 hours may be approximately 16% or less. The wet hardness reduction rate after immersion at a temperature of approximately 30°C for approximately 24 hours may be approximately 15% or less. The wet hardness reduction rate after immersion at a temperature of approximately 30°C for 24 hours may be approximately 14% or less. The wet hardness reduction rate after immersion at a temperature of approximately 30°C for 24 hours may be approximately 13% or less. The wet hardness reduction rate after immersion at a temperature of approximately 30°C for 24 hours may be approximately 12% or less. The minimum value of the wet hardness reduction rate after immersion at a temperature of approximately 30°C for 24 hours may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0331] The percentage decrease in wet hardness after immersion at 30°C for 24 hours can be measured by the following method. First, the biodegradable polyester resin composition is processed to produce a polyester block having a thickness of approximately 2.5 mm. The initial hardness of the polyester block is measured before immersion, and the wet hardness of the polyester block is measured immediately after immersion in water at approximately 30°C for approximately 24 hours. Subsequently, the percentage decrease in wet hardness after immersion at 30°C for 24 hours can be derived using formula 4.

[0332] The biodegradable polyester resin composition can be dried at a temperature of approximately 80°C for approximately 20 minutes with a moisture content of approximately 500 ppm, placed in a stainless steel frame, and compressed at a temperature of approximately 210°C and a pressure of approximately 10 MPa for approximately 5 minutes to produce a polyester block having a thickness of approximately 2.5 mm.

[0333] The initial hardness may be approximately 30 to 45 on the Shore D hardness scale. The initial hardness may be approximately 33 to 43 on the Shore D hardness scale. The initial hardness may be approximately 35 to 41 on the Shore D hardness scale.

[0334] The wet hardness after immersion at 30°C for 24 hours may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 30°C for 24 hours may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 30°C for 1 hour may be approximately 30 to 38 on the Shore D scale.

[0335] The decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 16% or less. The decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 15% or less. The decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 14% or less. The decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 13% or less. The decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 12% or less. The minimum value of the decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0336] The wet hardness after immersion at 30°C for 0.5 hours may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 30°C for 0.5 hours may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 30°C for 0.5 hours may be approximately 30 to 39 on the Shore D scale.

[0337] The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 10% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 30°C for 0.5 hours is the value obtained by dividing the absolute difference between the wet hardness after immersion at 30°C for 24 hours and the wet hardness after immersion at 30°C for 0.5 hours by the initial hardness. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 7% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 30°C for 0.5 hours may be approximately 5% or less.

[0338] The decrease in wet hardness after immersion at 30°C for 1 hour may be approximately 16% or less. The decrease in wet hardness after immersion at 30°C for 1 hour may be approximately 15% or less. The decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 14% or less. The decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 13% or less. The decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 12% or less. The minimum value of the decrease in wet hardness after immersion at 30°C for 1 hour may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0339] The wet hardness after immersion at 30°C for 1 hour may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 30°C for 1 hour may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 30°C for 1 hour may be approximately 30 to 39 on the Shore D scale.

[0340] The deviation between the rate of decrease in wet hardness after immersion at 30°C for 1 hour and the rate of decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 10% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 1 hour and the rate of decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 7% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 1 hour and the rate of decrease in wet hardness after immersion at 30°C for 24 hours may be approximately 5% or less.

[0341] The decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 16% or less. The decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 15% or less. The decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 14% or less. The decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 13% or less. The decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 12% or less. The minimum value of the decrease in wet hardness after immersion at 30°C for 18 hours may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0342] The wet hardness after immersion at 30°C for 18 hours may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 30°C for 18 hours may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 30°C for 18 hours may be approximately 30 to 39 on the Shore D scale.

[0343] The deviation between the wet hardness reduction rate after immersion at 30°C for 24 hours and the wet hardness reduction rate after immersion at 30°C for 18 hours may be approximately 10% or less. The deviation between the wet hardness reduction rate after immersion at 30°C for 24 hours and the wet hardness reduction rate after immersion at 30°C for 18 hours may be approximately 7% or less. The deviation between the wet hardness reduction rate after immersion at 30°C for 24 hours and the wet hardness reduction rate after immersion at 30°C for 18 hours may be approximately 5% or less.

[0344] The decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 16% or less. The decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 15% or less. The decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 14% or less. The decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 13% or less. The decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 12% or less. The minimum value of the decrease in wet hardness after immersion at approximately 50°C for 24 hours may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0345] The wet hardness after immersion at 50°C for 24 hours may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 50°C for 24 hours may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 50°C for 24 hours may be approximately 30 to 39 on the Shore D scale.

[0346] The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 50°C for 24 hours may be approximately 10% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 50°C for 24 hours may be approximately 7% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 50°C for 24 hours may be approximately 5% or less.

[0347] The decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 16% or less. The decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 15%. The decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 14% or less. The decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 13% or less. The decrease in wet hardness after immersion at 50°C for 24 hours may be approximately 12% or less. The minimum value of the decrease in wet hardness after immersion at 50°C for 24 hours may be approximately 1%, approximately 3%, approximately 5%, or approximately 6%.

[0348] The wet hardness after immersion at 70°C for 24 hours may be approximately 28 to 43 on the Shore D scale. The wet hardness after immersion at 70°C for 24 hours may be approximately 29 to 41 on the Shore D scale. The wet hardness after immersion at 70°C for 1 hour may be approximately 30 to 39 on the Shore D scale.

[0349] The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 10% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 7% or less. The deviation between the rate of decrease in wet hardness after immersion at 30°C for 24 hours and the rate of decrease in wet hardness after immersion at 70°C for 24 hours may be approximately 5% or less.

[0350] Furthermore, the acid value of the biodegradable polyester resin composition according to the examples may be approximately 0.01 mg KOH / g to approximately 3 mg KOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be approximately 0.1 mg KOH / g to approximately 2.8 mg KOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be approximately 0.1 mg KOH / g to approximately 2.5 mg KOH / g.

[0351] The biodegradable polyester resin compositions according to the examples have an acid value within the range described above, and therefore may have the hydrolysis and biodegradation characteristics described above.

[0352] Furthermore, the biodegradable polyester resin composition according to the examples may contain silicon elements. The silicon elements may be derived from the hydrolysis-resistant agent or the like. The content of the silicon elements may be about 0.1 ppm to about 1000 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon elements may be about 0.5 ppm to about 500 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon elements may be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon elements may be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0353] Furthermore, the biodegradable polyester resin composition according to the examples may contain a metal element. The metal element may be derived from the metal salt. The content of the metal element may be about 0.1 ppm to about 200 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 0.5 ppm to about 150 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0354] Furthermore, the biodegradable polyester resin composition according to the examples may contain iron. The iron may be derived from the metal salt. The content of the iron may be about 0.1 ppm to about 200 ppm based on the biodegradable polyester resin composition according to the examples. The content of the iron may be about 0.5 ppm to about 150 ppm based on the biodegradable polyester resin composition according to the examples. The content of the iron may be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples. The content of the iron may be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0355] Furthermore, the ratio of the iron element content to the silicon element content (ppm content of iron element / ppm content of silicon element) may be approximately 0.1 to approximately 0.8. The ratio of the iron element content to the silicon element content (ppm content of iron element / ppm content of silicon element) may be approximately 0.1 to approximately 0.7. The ratio of the iron element content to the silicon element content (ppm content of iron element / ppm content of silicon element) may be approximately 0.3 to approximately 0.7. The ratio of the iron element content to the silicon element content (ppm content of iron element / ppm content of silicon element) may be approximately 0.35 to approximately 0.65.

[0356] The biodegradable polyester resin compositions according to the examples contain silicon and iron elements within the ranges described above, and may therefore have an appropriate degree of hydrolysis and an appropriate degree of biodegradation. In particular, the degree of hydrolysis can be appropriately adjusted according to the content of silicon elements, and the degree of biodegradation can be appropriately adjusted according to the content of iron elements.

[0357] The content of the silicon element and the metal can be measured by inductively coupled plasma optical emission spectroscopy.

[0358] In the biodegradable polyester resin compositions according to the examples, the wet hardness reduction rate is 15% or less. Therefore, the biodegradable polyester resin compositions according to the examples may have high moisture resistance. The biodegradable polyester resin compositions according to the examples can maintain high mechanical properties even when exposed to water or in high-humidity environments.

[0359] As a result, when the biodegradable polyester resin composition according to the examples is used for packaging foods with high moisture content, the deviation in mechanical properties can be minimized.

[0360] Furthermore, the biodegradable polyester resin composition according to the examples may also have hydrophobic properties. This allows the biodegradable polyester resin composition according to the examples to absorb less moisture from the air. As a result, the biodegradable polyester resin composition according to the examples may have improved storage stability.

[0361] The biodegradable polyester resin composition according to the examples may contain a silicone-based hydrolysis resistant agent. This may result in the biodegradable polyester resin composition according to the examples having improved hydrolysis resistance. Furthermore, the silicone-based hydrolysis resistant agent can function as a coupling agent to couple the polymer resin contained in the condensation polymerization composition.

[0362] As a result, the silicone-based hydrolysis resistant agent can improve the degree of polymerization of the biodegradable polyester resin composition according to the examples.

[0363] As a result, the biodegradable polyester resin composition according to the examples may have improved physical properties during the actual period of use and may be easily biodegradable after use.

[0364] The biodegradable polyester resin compositions according to the examples can be efficiently applied to packaging films and the like. That is, films made from the biodegradable polyester resin compositions according to the examples can be used for ordinary purposes such as packaging. In this case, the biodegradable polyester resin compositions according to the examples may have a low degree of hydrolysis initially, and the biodegradable polyester film can maintain a certain level of mechanical and chemical properties within the user's normal usage period.

[0365] In addition, since the biodegradable polyester resin composition according to the examples has a high degree of biodegradability, the film produced using the biodegradable polyester resin composition according to the examples may decompose easily when discarded after use.

[0366] The above will be explained in more detail with reference to the following examples. However, the following examples are for illustrative purposes only, and the scope of the examples is not limited to these.

[0367] <Manufacturing example> Preparation of pre-treated nanocellulose Dry powder cellulose nanocrystals (NVC-100, manufactured by Celluforce) with particle sizes ranging from approximately 1 μm to 50 μm were dispersed in water at a concentration of 1% by weight. The mixture was then ultrasonically treated with a tip-type ultrasonic disperser at an output of 20,000 J / s for 2 minutes to produce pre-treated nanocellulose.

[0368] Hydrolysis-resistant agent: 3-Glycidoxypropylmethyldiethoxysilane Metal salts: Iron nitrate

[0369] <Examples> Example 1 Manufacturing of biodegradable polyester resins Stage 1: Pre-treatment to obtain slurry As shown in Table 1, pre-treated nanocellulose, iron nitrate, 1,4-butanediol (1,4-BDO), and terephthalic acid (TPA) were mixed in a molar ratio (1,4-BDO:TPA) of 1.4:1 and introduced into a slurry tank (the bottom of the slurry tank was anchor-type, with a height of 40 mm to the agitator, and equipped with three rotating blades) without a catalyst. At this time, the D50 of the terephthalic acid (TPA) was 130 μm.

[0370] Next, the mixture was pretreated by stirring at 40°C at 100 rpm for 1 hour to obtain a slurry without phase separation.

[0371] Stage 2: Stage for obtaining the preliminary polymer. The slurry obtained in the first step was introduced into the reactor via a supply line, and 250 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), a titanium-based catalyst, was added. The primary esterification reaction was then carried out at 220°C and atmospheric pressure for approximately 1 hour and 30 minutes until 95% of the by-product water was discharged.

[0372] To the reaction product, 1,4-butanediol (1,4-BDO) was added based on the total moles of the diol component, adipic acid (AA) based on the total moles of the dicarboxylic acid component, and tetrabutyl titanate (Dupont, Tyzor TnBT), a titanium-based catalyst, was added at a concentration of 200 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. A secondary esterification reaction was then carried out at 210°C and atmospheric pressure for approximately 2 hours and 30 minutes until 95% of the by-product water was discharged, thereby producing a prepolymer with a number-average molecular weight of 1500 g / mol.

[0373] Stage 3: Stage in which a condensation polymerization reaction is carried out. To the aforementioned prepolymer, 5 wt% of the prepared oligomer, 400 ppm of a titanium-based catalyst, tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), and 500 ppm of a triethylene phosphate stabilizer were added based on the total weight of the prepolymer, and the mixture was stabilized for approximately 10 minutes. Subsequently, the reaction mixture was heated to 250°C and subjected to a condensation polymerization reaction at 0.5 torr for 4 hours to produce a polymer having a water-average molecular weight of 55,000 g / mol.

[0374] Subsequently, approximately 600 ppm of epoxyglycidylsilane was added to the polymer, using the polymer as a reference. Then, the polymer underwent a terminal group extension reaction at a temperature of approximately 240°C for approximately 10 minutes. After that, it was cooled to 5°C and cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0375] Examples 2-5 and Comparative Examples 1 and 2 As shown in Table 1 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystals, and hydrolysis resistant agents differ. Except for the contents and the steps described above, the other steps were carried out substantially with reference to Example 1.

[0376] Manufacturing of biodegradable polyester sheets After preparing two Teflon® sheets, a stainless steel (SUS) frame (area 12cm x 12cm) was placed on one of the Teflon® sheets. Approximately 7g of the manufactured polyester resin pellets were placed in the stainless steel (SUS) frame (area 12cm x 12cm), then covered with the other Teflon® sheet and placed in the center of a hot press (manufacturer: Wizwrap, model: WL1600SA) with a surface area of ​​approximately 25cm x 25cm. This was maintained at approximately 210°C under a pressure of approximately 10 MPa for approximately 3 minutes, then removed, and immediately cooled in water at approximately 20°C for approximately 30 seconds to produce a biodegradable polyester sheet with an area of ​​approximately 10cm x 10cm and a thickness of approximately 300 μm.

[0377] Manufacturing of biodegradable polyester film The biodegradable polyester resin pellets were dried at 80°C for 5 hours, and then melt-extruded at 160°C using a Blown Film Extrusion Line (manufactured by Yujin Engineering) to produce a biodegradable polyester film with a thickness of 50 μm.

[0378] [Table 1]

[0379] Evaluation Example 1: Average particle size (D50) and standard deviation <Average particle size (D50) and standard deviation of aromatic dicarboxylic acids> The average particle size (D50) and standard deviation (SD) of aromatic dicarboxylic acids (TPA or DMT) were determined using a Microtrac S3500 particle size analyzer (Microtrac Inc.) under the following conditions:

[0380] Usage environment -Temperature: 10~35℃, Humidity: 90%RH, non-condensing maximum - The average particle size distribution (D50) and standard deviation (SD) for each section were measured.

[0381] The aforementioned standard deviation represents the square root of the variance and can be calculated using software.

[0382] <Particle size of nanocellulose> For nanocellulose, particle size and particle size deviation were measured using the principle of dynamic light scattering (DLS) at a temperature of 25°C and a measurement angle of 175°C, using a Zetasizer Nano ZS (manufacturer: Marven). At this time, the peak value derived from the polydispersity index (PdI) with a confidence interval of 0.5 was measured as the particle size.

[0383] Evaluation Example 2: Degree of Hydrolysis The biodegradable polyester resins produced in the examples and comparative examples were immersed in water at 80°C (100% RH), and then subjected to an accelerated water decomposition test.

[0384] Specifically, 5g each of the polyester resins used in the examples and comparative examples were added to 500mL of deionized water (DI Water). The container was then sealed to prevent evaporation, and a water decomposition acceleration test was conducted in a convection oven at 80°C. The humidity environment for the biodegradable polyester sheets was the same as that used for 100% RH testing, as they were immersed in water.

[0385] The number-average molecular weight of the polyester resins in the examples and comparative examples was measured after a certain period of time using gel permeation chromatography (GPC). The degree of hydrolysis was derived by dividing the difference between the initial number-average molecular weight and the number-average molecular weight after the period of time by the initial number-average molecular weight.

[0386] Sample preparation: Dissolve 0.035 mg of PBAT chip in 1.5 ml of THF. Measuring device: Waters E2695 Flow rate: 1ml / min in THF Injection volume: 50μl Column temperature: 40℃ Detector:ELSD Column: Styragel Column HR 5E, HR4, HR2

[0387] Evaluation Example 3: Biodegradability The biodegradable polyester resins produced in the examples and comparative examples were mixed with the following compost and subjected to accelerated biodegradation tests at a temperature of 60°C and a humidity of 90%.

[0388] Using the aforementioned gel permeation chromatography (GPC), the number-average molecular weight of the polyester resins in the examples and comparative examples was measured after a certain period of time. The difference between the initial number-average molecular weight and the number-average molecular weight after the period of time, divided by the initial number-average molecular weight, was used to derive the biodegradability.

[0389] compost Manufacturer: TaeheungF&G Product Name: Chisei-do (by-product fertilizer, Grade 1 compost) Compost composition: Pig manure 40 wt%, chicken manure 15 wt%, sawdust 37 wt%, zeolite 5 wt%, microbial preparation 3 wt%

[0390] Evaluation Example 3: Acid Value A 0.02KOH solution was prepared by mixing KOH and ethyl alcohol. Subsequently, approximately 1 g of the biodegradable resin composition according to the examples and comparative examples was dissolved in chloroform. Then, the biodegradable resin composition solution was titrated with the KOH solution using phenolphthalein reagent as a reference, and the acid value was measured.

[0391] Acid value measurement equipment: Mettler Toledo Titrator Excellence T5

[0392] Evaluation Example 4: Iron and Silicon Content The biodegradable polyester pellets produced in the examples and comparative examples were dissolved in 65 wt% nitrous acid, and the iron and silicon content was measured by ICP OES.

[0393] Equipment: Agilent 5110 SVDV Measurement conditions RF power: 1.2KW Nebulizer flow: 0.7 L / min Plasma flow: 12 L / min Auxiliary flow: 1L / min Read time: 5s

[0394] As shown in Table 3 below, the degree of biodegradation has been measured.

[0395] [Table 3]

[0396] As shown in Table 4 below, the degree of hydrolysis has been measured.

[0397] [Table 4]

[0398] As shown in Table 5 below, the degree of biodegradation per aliphatic dicarboxylic acid was derived.

[0399] [Table 5]

[0400] As shown in Table 6 below, the iron and silicon content has been measured.

[0401] [Table 6]

[0402] As described in Tables 2 to 6 above, the biodegradable resin compositions according to the examples may have an appropriate degree of hydrolysis, an appropriate degree of biodegradation, and an appropriate degree of biodegradation per degree of hydrolysis. That is, the biodegradable resin compositions according to the examples may have a low initial degree of hydrolysis and a high final degree of biodegradation. [Industrial applicability]

[0403] The examples can be used in biodegradable resin compositions, films, and molded articles.

Claims

1. A method for producing a biodegradable polyester resin composition, A step of forming a prepolymer by esterifying a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, The steps include: condensing the aforementioned prepolymer to form a condensation polymer composition; The steps include reacting the aforementioned polymerization composition with a silicon-based hydrolysis resistant agent, The step of adding the metal salt, The metal salt contains iron, The biodegradable polyester resin composition contains a silicon element, The ratio of iron to silicon mass is approximately 0.1 to approximately 0.

7. The iron content is approximately 1 ppm to approximately 100 ppm. The content of the aforementioned silicon element is approximately 1 ppm to approximately 150 ppm. The degree of hydrolysis after one week was approximately 35% to 60%. The degree of hydrolysis after 3 weeks was approximately 85% or higher. The degree of hydrolysis after one week and the degree of hydrolysis after three weeks were measured by the following measurement method. The aforementioned diol contains 1,4-butanediol in an amount of 98 mol% or more, based on the total diol content. The aforementioned aromatic dicarboxylic acid contains terephthalic acid or dimethyl terephthalate in an amount of 43 mol% to 53 mol% based on the total dicarboxylic acid. The aliphatic dicarboxylic acid contains adipic acid in an amount of 47 mol% to 57 mol% based on the total dicarboxylic acid. A method for producing a biodegradable polyester resin composition. [Measurement method] The degree of hydrolysis after one week is the rate of decrease in the number-average molecular weight of the biodegradable polyester resin composition compared to its initial state, when the biodegradable polyester resin composition is left for one week under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity. The degree of hydrolysis after three weeks is the rate of decrease in the number-average molecular weight of the biodegradable polyester resin composition compared to its initial state, when the biodegradable polyester resin composition is left for three weeks under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity.

2. The hydrolysis-resistant agent comprises a silane containing two or more functional groups. A method for producing the biodegradable polyester resin composition according to claim 1.

3. The hydrolysis-resistant agent comprises an epoxy group or an alkoxy group. A method for producing the biodegradable polyester resin composition according to claim 2.

4. The step of reacting the aforementioned polymerization composition with the aforementioned silicon-based hydrolysis resistant agent is: The process includes a step of reacting the aforementioned polymerization composition and the aforementioned silicon-based hydrolysis resistant agent at a temperature of approximately 180°C to approximately 260°C for 5 to 60 minutes. A method for producing the biodegradable polyester resin composition according to claim 1.

5. The acid value is approximately 2.0 mg KOH / g or less. A method for producing the biodegradable polyester resin composition according to claim 1.

6. A polyester resin containing diols, aromatic dicarboxylic acids and aliphatic dicarboxylic acids, Metal salts and The element silicon, Includes, The aforementioned metal salt contains iron, The ratio of iron to silicon mass is approximately 0.1 to approximately 0.

7. The iron content is approximately 1 ppm to approximately 100 ppm. The content of the aforementioned silicon element is approximately 1 ppm to approximately 150 ppm. The degree of hydrolysis after one week was approximately 35% to 60%. The degree of hydrolysis after 3 weeks was approximately 85% or higher. The degree of hydrolysis after one week and the degree of hydrolysis after three weeks were measured by the following measurement method. The aforementioned diol contains 1,4-butanediol in an amount of 98 mol% or more, based on the total diol content. The aforementioned aromatic dicarboxylic acid contains terephthalic acid or dimethyl terephthalate in an amount of 43 mol% to 53 mol% based on the total dicarboxylic acid. The aliphatic dicarboxylic acid contains adipic acid in an amount of 47 mol% to 57 mol% based on the total dicarboxylic acid. Biodegradable polyester resin composition. [Measurement method] The degree of hydrolysis after one week is the rate of decrease in the number-average molecular weight of the biodegradable polyester resin composition compared to its initial state, when the biodegradable polyester resin composition is left for one week under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity. The degree of hydrolysis after three weeks is the rate of decrease in the number-average molecular weight of the biodegradable polyester resin composition compared to its initial state, when the biodegradable polyester resin composition is left for three weeks under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity.

7. It also contains nanocellulose, The aforementioned nanocellulose contains sulfur, The biodegradable polyester resin composition according to claim 6.

8. The wet hardness reduction rate is approximately 15% or less. The aforementioned wet hardness reduction rate is measured by the following measurement method: The biodegradable polyester resin composition according to claim 6. [Measurement method] The biodegradable polyester resin composition is processed to produce a polyester block having a thickness of approximately 2.5 mm. The initial hardness of the polyester block and the wet hardness after the polyester block has been immersed in water at approximately 30°C for approximately 24 hours are measured. The wet hardness reduction rate is the value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

9. A polyester resin containing diols, aromatic dicarboxylic acids and aliphatic dicarboxylic acids, Metal salts and The element silicon, Includes, The aforementioned metal salt contains iron, The ratio of iron to silicon mass is approximately 0.1 to approximately 0.

7. The iron content is approximately 1 ppm to approximately 100 ppm. The content of the aforementioned silicon element is approximately 1 ppm to approximately 150 ppm. The degree of hydrolysis after one week was approximately 35% to 60%. The degree of hydrolysis after 3 weeks was approximately 85% or higher. The degree of hydrolysis after one week and the degree of hydrolysis after three weeks were measured by the following measurement method. The aforementioned diol contains 1,4-butanediol in an amount of 98 mol% or more, based on the total diol content. The aforementioned aromatic dicarboxylic acid contains terephthalic acid or dimethyl terephthalate in an amount of 43 mol% to 53 mol% based on the total dicarboxylic acid. The aliphatic dicarboxylic acid contains adipic acid in an amount of approximately 47 mol% to approximately 57 mol% based on the total dicarboxylic acid. Biodegradable polyester molded product. [Measurement method] The degree of hydrolysis after one week is the rate of decrease in the number-average molecular weight of the biodegradable polyester molded product compared to its initial state, when the biodegradable polyester molded product is left for about one week under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity. The degree of hydrolysis after three weeks is the rate of decrease in the number-average molecular weight of the biodegradable polyester molded product compared to its initial state, when the biodegradable polyester molded product is left for three weeks under high temperature and high humidity conditions of approximately 80°C and approximately 100% humidity.

10. It also contains nanocellulose, The aforementioned nanocellulose contains sulfur, The biodegradable polyester molded article according to claim 9.

11. The wet hardness reduction rate is approximately 15% or less. The aforementioned wet hardness reduction rate is measured by the following measurement method: The biodegradable polyester molded article according to claim 9. [Measurement method] The biodegradable polyester molded product is processed to produce a polyester block having a thickness of approximately 2.5 mm. The initial hardness of the polyester block and the wet hardness after the polyester block has been immersed in water at approximately 30°C for approximately 24 hours are measured. The wet hardness reduction rate is the value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

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