Biodegradable polyester resin composition and biodegradable polyester molded article containing the same

Abstract

The present invention provides a biodegradable polyester resin composition containing a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a hydrophilicity regulator having a molecular weight of 400 to 1300 in an amount of 5000 ppm to 20000 ppm. The hydrophilicity regulator may contain an oligomer formed by reacting at least two or more of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid.

Description

Technical Field

[0001] The examples relate to a biodegradable polyester resin composition, a biodegradable polyester film containing 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 disposal problems of various daily necessities, particularly disposable products, have been demanded. Specifically, polymer materials are inexpensive and have excellent properties such as processability, and are widely used in manufacturing various products such as films, fibers, packaging materials, bottles, and containers. However, when the life of the used products 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] To overcome these limitations of these polymers, active research has been conducted on biodegradable polymers that are decomposed within a short time. 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 Publication No. 2012-0103158, etc.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The examples aim to provide a biodegradable polyester resin composition having an appropriate initial degree of hydrolysis and an appropriate degree of biodegradation, and having a high degree of hydrolysis not only in soil but also in water at the time of disposal, and a biodegradable polyester film containing the same.

Means for Solving the Problems

[0006] The biodegradable polyester resin composition according to the embodiment contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a hydrophilicity regulator having a molecular weight of 400 to 1300 in an amount of 5000 ppm to 20000 ppm.

[0007] In one embodiment, the hydrophilicity regulator includes an oligomer formed by the reaction of at least two or more of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid.

[0008] In the biodegradable polyester resin composition according to one embodiment, the degree of hydrolysis after 1 week is 35% to 60%, and the degree of hydrolysis after 3 weeks is 85% or more. The degree of hydrolysis after 1 week and the degree of hydrolysis after 3 weeks are measured by the following measurement method.

[0009] [Measurement method] The degree of hydrolysis after 1 week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester film is placed for 1 week under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%. The degree of hydrolysis after 3 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester film is placed for 3 weeks under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%.

[0010] In one embodiment, the hydrophilicity regulator may include a first oligomer having a molecular weight between 415 and 425, a second oligomer having a molecular weight between 620 and 630, a third oligomer having a molecular weight between 640 and 650, and a fourth oligomer having a molecular weight between 840 and 850.

[0011] In one embodiment, the content of the first oligomer is 3000 to 5000 ppm based on the polyester resin, the content of the second oligomer is 2000 ppm to 4000 ppm based on the polyester resin, the content of the third oligomer is 500 ppm to 2000 ppm based on the polyester resin, and the content of the fourth oligomer may be 700 ppm to 2500 ppm based on the polyester resin.

[0012] In one embodiment, the hydrophilicity regulator contains a first oligomer, and the first oligomer may contain one first unit represented by the following Chemical Formula 8 and one second unit represented by the following Chemical Formula 9.

[0013]

Chemical Formula

[0014]

Chemical Formula

[0015] In one embodiment, the hydrophilicity regulator contains a second oligomer and a third oligomer. The second oligomer contains one of the first units and two of the second units, and the third oligomer contains two of the first units and one of the second units. The second oligomer may be contained in the hydrophilicity regulator in a higher content than the third oligomer.

[0016] In one embodiment, the hydrophilicity regulator further contains a fourth oligomer, and the fourth oligomer may contain two of the first units and two of the second units.

[0017] In the biodegradable polyester resin composition according to one embodiment, the water contact angle measured by the following measurement method may be 65° to 90°, and the polarity measured by the following measurement method may be 4 mN / m to 7 mN / m.

[0018] [Measuring Method] The biodegradable polyester resin composition is dried at a temperature of 80°C, placed in a stainless-steel frame, compressed at a temperature of 210°C and a pressure of 10 MPa for 3 minutes to produce a polyester sheet having a thickness of 300 μm, and the water contact angle and the polarity degree on the surface of the polyester sheet are measured.

[0019] In the biodegradable polyester resin composition according to one embodiment, the biodegradation degree after 1 week is 45% - 65%, and the biodegradation degree after 9 weeks is 85% or more. The biodegradation degree after 1 week and the biodegradation degree after 9 weeks can be measured by the following measuring method.

[0020] [Measuring Method] The biodegradation degree after 1 week is the reduction rate of the molecular weight of the polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for 1 week under composting conditions, a temperature of 60°C and a humidity of 90%. The biodegradation degree after 9 weeks is the reduction rate of the molecular weight of the polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for 9 weeks under composting conditions, a temperature of 60°C and a humidity of 90%.

[0021] The biodegradable polyester resin composition according to the example contains a polyester resin containing a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid. The degree of hydrolysis after 1 week is 35% - 60%, and the degree of hydrolysis after 3 weeks is 85% or more. The degree of hydrolysis after 1 week and the degree of hydrolysis after 3 weeks are measured by the following measuring method.

[0022] [Measuring Method] The degree of hydrolysis after 1 week is the reduction rate of the number-average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for 1 week under high-temperature and high-humidity conditions of a temperature of 80°C and a humidity of 100%. The degree of hydrolysis after 3 weeks is the reduction rate of the number-average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for 3 weeks under high-temperature and high-humidity conditions of a temperature of 80°C and a humidity of 100%.

[0023] In a biodegradable polyester resin composition according to an embodiment, the biodegradation degree after 9 weeks is 85% or more, and the biodegradation degree after 9 weeks may be the reduction rate of the molecular weight of the biodegradable polyester resin composition with respect to the initial when the biodegradable polyester resin composition is placed for 9 weeks under composting conditions, a temperature of 60°C and a humidity of 90%.

[0024] In a biodegradable polyester resin composition according to an embodiment, the biodegradation degree after 1 week is 45% to 75%, and the biodegradation degree after 1 week may be the reduction rate of the molecular weight of the biodegradable polyester resin composition with respect to the initial when the biodegradable polyester resin composition is placed for 1 week under composting conditions, a temperature of 60°C and a humidity of 90%.

[0025] In a biodegradable polyester resin composition according to an embodiment, the hydrolysis degree after 2 weeks is 80% to 95%, and the hydrolysis degree after 2 weeks may be the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial when the biodegradable polyester resin composition is placed for 2 weeks under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%.

[0026] In a biodegradable polyester resin composition according to an embodiment, the hydrolysis degree after 4 weeks is 85% or more, the hydrolysis degree after 4 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial when the biodegradable polyester resin composition is placed for 4 weeks under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%, and the increase rate of the hydrolysis degree from 1 week to 2 weeks may be 29% / week to 50% / week, and the increase rate of the hydrolysis degree from 3 weeks to 4 weeks may be 0.01% / week to 3% / week.

[0027] In the biodegradable polyester resin composition according to an embodiment, the biodegradability after 4 weeks is 73% to 85%, and the biodegradability after 4 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for 4 weeks under high temperature and high humidity conditions of 80 ° C and 100% humidity. The increase rate of biodegradability from 1 week to 4 weeks may be 3.5% / week to 8% / week.

[0028] In the biodegradable polyester resin composition according to an embodiment, the acid value may be 2.0 mgKOH / g or less.

[0029] In the biodegradable polyester resin composition according to an embodiment, an oligomer having a molecular weight of 400 to 1300 may be contained at 5000 ppm to 20000 ppm based on the total composition.

[0030] In the biodegradable polyester resin composition according to an embodiment, the oligomer may contain the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid.

[0031] The biodegradable molded article according to the embodiment may include a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a hydrophilicity regulator having a molecular weight of 400 to 1300 at 5000 ppm to 20000 ppm.

Advantages of the Invention

[0032] The biodegradable polyester resin composition according to the embodiment contains a hydrophilicity regulator having a molecular weight of about 400 to about 1300. Further, the hydrophilicity regulator can adjust the hydrophilicity and / or hydrophobicity of the biodegradable polyester resin composition according to the embodiment. Thereby, the hydrophilicity regulator can adjust the degree of hydrolysis of the biodegradable polyester resin composition according to the embodiment.

[0033] Depending on the hydrophilicity regulator and the manufacturing process, etc., the biodegradable polyester resin composition according to the examples may have the appropriate degree of hydrolysis and the appropriate degree of biodegradability.

[0034] In particular, the biodegradable polyester resin composition according to the examples has a low initial degree of hydrolysis and a high later-stage degree of hydrolysis. Also, the biodegradable polyester resin composition according to the examples may have a degree of biodegradability per appropriate degree of hydrolysis.

[0035] As a result, the biodegradable polyester resin composition according to the examples can be efficiently applied to packaging films and the like. That is, the film produced from the biodegradable polyester resin composition according to the examples can be used for normal applications such as packaging. At this time, since the biodegradable polyester resin composition according to the examples has a low initial degree of hydrolysis, within the general usage period of the user, the biodegradable polyester film can maintain mechanical and chemical physical properties to a certain extent or more.

[0036] Also, since the biodegradable polyester resin composition according to the examples has a high later-stage degree of hydrolysis, the film produced from the biodegradable polyester resin composition according to the examples may be easily decomposed when discarded after use. In particular, since the biodegradable polyester resin composition according to the examples has a high later-stage hydrolysis, the decomposition by ambient moisture and the decomposition by microorganisms in the biodegradable polyester resin composition according to the examples can complement each other. As a result, the biodegradable polyester resin composition according to the examples may have a low initial degree of hydrolysis and a high degree of biodegradability.

[0037] Also, the biodegradable polyester resin composition according to the examples may have a degree of biodegradability per 1.5 or more aliphatic carboxylic acids. That is, the biodegradable polyester resin composition according to the examples has a low content of aliphatic carboxylic acids and a high degree of biodegradability.

[0038] Accordingly, the biodegradable polyester resin composition according to the examples may have a relatively high content of aromatic carboxylic acid, and thus may have high hydrolysis resistance initially and high biodegradability later.

[0039] The biodegradable polyester resin composition according to the examples can maintain mechanical and chemical physical properties above a certain level within the user's usage period. At the same time, since the biodegradable polyester resin composition according to the examples has a high degree of later hydrolysis, it may be easily decomposed in a river or the sea. That is, the biodegradable polyester resin composition according to the examples can solve environmental problems such as the marine plastic problem.

Brief Description of the Drawings

[0040]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0041] Hereinafter, the invention will be described in detail with reference to implementation examples. The implementation examples are not limited to the content disclosed below, and can be modified into various forms without changing the gist of the invention.

[0042] In this specification, when a part includes a component, unless otherwise stated, it does not exclude other components and may further include other components.

[0043] Also, it should be understood that any numerical range indicating physical property values, dimensions, etc. of the components described in this specification is modified by the term "about" unless otherwise stated.

[0044] Terms such as first, second, primary, and secondary in this specification are used to describe various components, and the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0045] The biodegradable polyester resin composition according to the examples contains a biodegradable polyester resin. The biodegradable polyester resin composition according to the examples may contain the biodegradable polyester resin alone or together with other resins or additives.

[0046] The biodegradable polyester resin contains a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The biodegradable polyester resin contains 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 contains 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.

[0047] In the description of the biodegradable polyester resin composition according to the examples, the diol residue may be represented by the diol. In the biodegradable polyester resin, the dicarboxylic acid residue may be represented by the dicarboxylic acid. Also, the residue can be expressed by the component.

[0048] The diol may be an aliphatic diol. The diol may be selected from at least one or more of the group consisting of 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-1,3-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.

[0049] The diol may be selected from at least one or more of the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, diethylene glycol, neopentyl glycol, or derivatives thereof.

[0050] The diol may be selected from at least one or more of the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or derivatives thereof.

[0051] The diol may contain 1,4-butanediol or a derivative thereof.

[0052] 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, phenanthrenedicarboxylic acid, or derivatives thereof.

[0053] The aromatic dicarboxylic acid may be at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, 2,6-naphthalenedicarboxylic acid, isophthalic acid, or derivatives thereof.

[0054] The aromatic dicarboxylic acid may contain terephthalic acid, dimethyl terephthalate or derivatives thereof.

[0055] 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.

[0056] The aliphatic dicarboxylic acid may be at least one selected from the group consisting of adipic acid, succinic acid, sebacic acid, or derivatives thereof.

[0057] The aliphatic dicarboxylic acid may contain adipic acid or a derivative thereof.

[0058] In the biodegradable polyester resin, the molar ratio of the total diol residues containing the diol to the total dicarboxylic acid residues containing 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.

[0059] 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.

[0060] The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of about 90 mol% or more based on the total diol. The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of about 95 mol% or more based on the total diol. The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of about 98 mol% or more based on the total diol.

[0061] The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 43 mol% to about 55 mol% based on the total dicarboxylic acid.

[0062] The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 47 mol% to about 57 mol% based on the total dicarboxylic acid.

[0063] Also, the biodegradable polyester resin may contain 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.

[0064] The first block may contain the diol residue and the aromatic dicarboxylic acid residue. The first block may be formed by an esterification reaction of the diol and the aromatic dicarboxylic acid. The first block may contain only the diol residue and the aromatic dicarboxylic acid residue. The first block may contain only the repeating units formed by the esterification reaction of the diol and the aromatic dicarboxylic acid. That is, the first block may mean the sum of the repeating units of the diol and the aromatic dicarboxylic acid before the aliphatic dicarboxylic acid binds.

[0065] The second block may contain the diol residue and the aliphatic dicarboxylic acid residue. The second block may be formed by an esterification reaction of the diol and the aliphatic dicarboxylic acid. The second block may contain only the diol residue and the aliphatic dicarboxylic acid residue. The second block may contain only the repeating units formed by the esterification reaction of the diol and the aliphatic dicarboxylic acid. That is, the second block may mean the sum of the repeating units of the diol and the aliphatic dicarboxylic acid before the aromatic dicarboxylic acid binds.

[0066] In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be from about 0.5 to about 1.5. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be from about 0.6 to about 1.4. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be from about 0.7 to about 1.3. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be from about 0.75 to about 1.2. Further, in the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be 0.8 to 1.1. The number of the first blocks may be even smaller than the number of the second blocks.

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

[0068] 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 polymerization process described below. That is, as the molar ratio of the aromatic dicarboxylic acid increases and as the molecular weight of the biodegradable polyester resin increases, the number of the first blocks may increase.

[0069] The number of the second blocks may be about 30 to about 300. The number of the second blocks may be about 40 to about 250. The number of the second blocks may be about 50 to about 220. The number of the second blocks may be about 60 to about 200. The number of the second blocks may be about 70 to about 200. The number of the second blocks may be about 75 to about 200.

[0070] The number of the second blocks may vary depending on the content of the aliphatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the polymerization process described later. That is, as the molar ratio of the aliphatic dicarboxylic acid increases and as the molecular weight of the biodegradable polyester resin increases, the number of the first blocks may increase.

[0071] When the biodegradable polyester resin contains the first block and the second block within the above ranges, the biodegradable polyester resin composition according to the examples may have appropriate mechanical strength and appropriate biodegradability. Further, when the biodegradable polyester resin contains the first block and the second block within the above ranges, the biodegradable polyester resin composition according to the examples may have improved flexibility and improved rigidity. Thereby, the biodegradable polyester resin composition according to the examples can be easily used for injection molded products and the like. Further, when the biodegradable polyester resin contains the first block and the second block within the above ranges, the biodegradable polyester resin composition according to the examples may have appropriate durability against ultraviolet rays and the like and appropriate biodegradability.

[0072] The first block may be represented by Chemical Formula 1 below.

[0073]

Chemical Formula

[0074] Here, R1 is a substituted or unsubstituted arylene 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 an integer from 1 to 20.

[0075] R1 is a substituted or unsubstituted phenylene group, and R2 may be a butylene group.

[0076] The second block may be represented by Chemical Formula 2 below.

[0077]

Chemical Formula

[0078] Here, R3 and R4 are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n may be an integer from 1 to 20.

[0079] R3 and R4 may be butylene groups.

[0080] 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 be represented by Chemical Formula 3 below.

[0081]

Chemical Formula

[0082] Here, R1 is a substituted or unsubstituted arylene 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 an integer from 1 to 20. Also, R3 and R4 are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n may be an integer from 1 to 20.

[0083] The diol residue includes a residue of 1,4-butanediol or a derivative thereof, the aromatic dicarboxylic acid residue includes 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.

[0084] For example, the biodegradable polyester resin may include a first block including a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof.

[0085] Alternatively, the biodegradable polyester resin may include a first block including a residue of 1,4-butanediol or a derivative thereof and a residue of dimethyl terephthalate or a derivative thereof.

[0086] The biodegradable polyester resin may include a second block including a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

[0087] Alternatively, the biodegradable polyester resin may include a second block including a residue of 1,4-butanediol or a derivative thereof and a residue of succinic acid or a derivative thereof.

[0088] The biodegradable polyester resin according to an embodiment of the present invention may include a first block including a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof, and a second block including a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

[0089] The first block may be represented by the following Chemical Formula 4, and the second block may be represented by the following Chemical Formula 5.

[0090]

Chemical Formula

[0091] Here, the m may be from 1 to 20.

[0092]

Chemical formula

[0093] Here, the n may be from 1 to 20.

[0094] The biodegradable polyester resin may be the one represented by the following Chemical formula 6.

[0095]

Chemical formula

[0096] Here, the m is from 1 to 20, and the n may be from 1 to 20.

[0097] When the first block and the second block satisfy the above configuration, it may be more advantageous for providing a biodegradable polyester sheet, film or molded article excellent in biodegradability and hydrolysis resistance and having improved physical properties.

[0098] Further, when the biodegradable polyester resin contains the first block and the second block within the above range, the biodegradable polyester resin composition according to the examples may have appropriate mechanical properties and appropriate UV resistance properties.

[0099] Since the first block and the second block have the above characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0100] Since the first block and the second block have the above characteristics, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance properties.

[0101] Since the first block and the second block have the above characteristics, the biodegradable polyester resin composition according to the example may have an appropriate biodegradation rate.

[0102] Since the first block and the second block have the above characteristics, the biodegradable polyester resin composition according to the example may have an appropriate hydrolysis rate.

[0103] The biodegradable polyester resin may further contain a branching agent. The branching agent may contain a trihydric or higher alcohol and / or a trihydric or higher carboxylic acid. 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 as a part of the molecular structure in the biodegradable polyester resin.

[0104] The trihydric or higher alcohol may be at least one selected from the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0105] The above trivalent or higher carboxylic acid may be at least one selected from the group consisting of methane tricarboxylic acid, ethanetricarboxylic 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.

[0106] The branching agent may be contained in the biodegradable polyester resin at a content of about 0.1 wt% to about 5 wt% based on the whole biodegradable polyester resin. The branching agent may be contained in the biodegradable polyester resin at a content of about 0.1 wt% to about 3 wt% based on the whole biodegradable polyester resin. The branching agent may be contained in the biodegradable polyester resin at a content of about 0.1 wt% to about 1 wt% based on the whole biodegradable polyester resin.

[0107] Since the biodegradable polyester resin contains the branching agent within the above range, the biodegradable polyester resin composition according to the examples may have appropriate mechanical properties and appropriate biodegradability.

[0108] The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 30 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 50 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 70 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 80 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 90 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 95 wt% or more based on the weight of the entire composition. The biodegradable polyester resin composition according to the embodiment may contain the biodegradable resin in a content of about 99 wt% or more based on the weight of the entire composition. The maximum content of the biodegradable resin in the biodegradable polyester resin composition according to the embodiment may be about 100 wt% based on the weight of the entire composition.

[0109] The biodegradable polyester resin composition according to the embodiment may further contain a reinforcing material. The reinforcing material can improve the mechanical properties of the biodegradable polyester resin composition according to the embodiment and the film or molded article produced thereby. Further, the reinforcing material can adjust the deformation characteristics of the biodegradable polyester resin composition according to the embodiment by ultraviolet rays. Further, the reinforcing material can adjust the hydrolysis characteristics of the biodegradable polyester resin composition according to the embodiment. Further, the reinforcing material can adjust the biodegradability of the biodegradable polyester resin according to the embodiment.

[0110] The reinforcing material may be derived from biomass. The reinforcing material may be a fiber made of an organic substance. The reinforcing material may be nanocellulose.

[0111] The nano-cellulose may be one or more selected from the group consisting of nano-crystalline cellulose, cellulose nanofibers, microfibrillated cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, pentyl cellulose, hexyl cellulose, or cyclohexyl cellulose.

[0112] The nano-cellulose may contain a metal bonded by an ionic bond. The nano-crystalline cellulose may contain a sodium element. Also, the nano-crystalline cellulose may contain a sulphate. The nano-crystalline cellulose may contain a carboxylate. The nano-crystalline cellulose may be cellulose hydrogen sulphate sodium salt.

[0113] The nano-cellulose may be represented by Chemical Formula 7 below.

[0114] [Chemical Formula]

[0115] Here, x is from 1 to 35, and y may be from 1 to 10. x is from 15 to 35, and y may be from 1 to 10.

[0116] The nano-cellulose may have a specific surface area of about 200 m 2 / g to about 600 m 2 / g. The nano-cellulose may have a specific surface area of about 250 m 2 / g to about 500 m 2 / g.

[0117] The weight average molecular weight of the nanocellulose may be about 10,000 g / mol to about 40,000 g / mol. The weight average molecular weight of the nanocrystalline cellulose may be about 11,000 g / mol to about 35,000 g / mol.

[0118] The moisture content of the nanocrystalline cellulose may be about 2 wt% to about 8 wt%. The moisture content of the nanocrystalline cellulose may be about 4 wt% to about 6 wt%.

[0119] 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.

[0120] The average length of the nanocellulose may be about 20 nm to about 300 nm. The average length of the nanocellulose may be about 30 nm to about 180 nm. The average length of the nanocellulose may be about 35 nm to about 150 nm.

[0121] By the diameter and length of the nanocellulose satisfying the above ranges, the biodegradability and physical properties of the biodegradable polyester resin, or the biodegradable polyester sheet, film and molded article obtained using the same can be further improved.

[0122] The diameter and length of the nanocellulose can be measured by atomic force microscopy in a state dispersed in water.

[0123] The sulfur content of the nanocellulose may be about 0.1 wt% to about 1.2 wt% based on the whole of the nanocrystalline cellulose. The sulfur content of the nanocrystalline cellulose may be about 0.75 wt% to about 1.1 wt% based on the whole of the nanocellulose.

[0124] The pH of the nanocellulose may be 5 to 7. The pH of the nanocellulose may be 6 to 7.

[0125] The zeta potential of the nanocellulose may be from about -25 mV to about -50 mV. The zeta potential of the nanocellulose may be from about -30 mV to about -45 mV.

[0126] The nanocellulose may be included in the biodegradable polyester resin composition according to the examples in an amount of about 0.01 part 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 part 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 part 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 part by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0127] Since the nanocellulose has the above characteristics, it may be uniformly dispersed in the biodegradable polyester resin composition according to the examples.

[0128] Since the nanocellulose has the above characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0129] In addition, the nanocellulose functions as a nucleating agent and can improve the crystallization rate of the biodegradable polyester resin composition according to the examples. Thereby, the nanocellulose can increase the crystallization temperature of the biodegradable polyester resin composition according to the examples.

[0130] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance characteristics.

[0131] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have an appropriate biodegradation rate.

[0132] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have an appropriate hydrolysis rate.

[0133] The biodegradable polyester resin composition according to the examples may contain a metal salt.

[0134] The metal salt may be contained in an amount of about 0.1 ppm to about 1000 ppm, based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be contained in an amount of about 1 ppm to about 500 ppm, based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be contained in an amount of about 1 ppm to about 100 ppm, based on the total weight of the biodegradable polyester resin composition according to the examples. The metal salt may be contained in an amount of about 1 ppm to about 50 ppm, based on the total weight of the biodegradable polyester resin composition according to the examples.

[0135] At least one or more of the metal salts may be selected from the group consisting of nitrates, sulfates, hydrochlorides, or carboxylates. At least one or more of the metal salts 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. At least one or more of the metal salts may be selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, or sodium nitrate.

[0136] The metal salt may contain one or more 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).

[0137] Also, the metal salt may be selected from the group consisting of acetate, nitrate, nitride, sulfide, sulfate, sulfoxide, hydroxide, hydrate, chloride, chlorinate, and bromide.

[0138] Since the biodegradable polyester resin composition according to the examples contains the metal salt in the above content, the hydrolysis rate and the biodegradation rate can be appropriately adjusted.

[0139] The biodegradable polyester resin composition according to the examples may further contain a hydrolysis-resistant agent.

[0140] The hydrolysis-resistant agent may be selected from at least one or more silicon-based compounds such as silane, silazane, or siloxane.

[0141] 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 or more selected from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-Glycidoxypropyl methyldimethoxysilane, 3-Glycidoxypropyl trimethoxysilane, 3-Glycidoxypropyl methyldiethoxysilane, or 3-Glycidoxypropyl triethoxysilane.

[0142] The hydrolysis-resistant agent may be contained 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 contained 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 contained 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 contained in the biodegradable polyester resin composition according to the examples in a content of about 10 ppm to 300 ppm.

[0143] The hydrolysis-resistant agent may be bonded to the biodegradable polyester resin. The hydrolysis-resistant agent may be chemically bonded to the biodegradable polyester resin. The hydrolysis-resistant agent may be chemically bonded to the polymer contained in the biodegradable polyester resin. The hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin to each other.

[0144] The biodegradable polyester resin composition according to the examples may have appropriate hydrolysis resistance characteristics because it contains the hydrolysis-resistant agent within the above range. In particular, the biodegradable polyester resin according to the examples may have appropriate initial hydrolysis characteristics and improved biodegradability because it contains the hydrolysis-resistant agent within the above range.

[0145] Accordingly, the biodegradable polyester resin composition according to the examples may contain a silicon element. The biodegradable polyester resin composition according to the examples may contain a silicon element at a content of about 0.1 ppm to about 100 ppm. The biodegradable polyester resin composition according to the examples may contain a silicon element at a content of about 0.1 ppm to about 50 ppm. The biodegradable polyester resin composition according to the examples may contain a silicon element at a content of about 0.1 ppm to about 20 ppm.

[0146] Also, the hydrolysis-resistant agent can also react with terminal carboxyl groups or unreacted carboxyl groups. Accordingly, the biodegradable polyester resin composition according to the examples may have a low acid value.

[0147] Also, the hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin, so that the proportion of high-molecular-weight polymers in the biodegradable polyester resin composition according to the examples can be increased. Accordingly, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0148] The biodegradable polyester resin composition according to the examples may further contain a chain extender.

[0149] The chain extender may contain isocyanate.

[0150] The chain extender may be at least one selected from the group consisting of monofunctional isocyanate or polyfunctional isocyanate.

[0151] The chain extender may be at least one selected from the group consisting of tolylene 2,4-diisocyanate, tolylene 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).

[0152] The chain extender may contain triisocyanate. The chain extender may contain tris(4-isocyanatophenyl)methane.

[0153] The chain extender may contain an acrylic polymer. The acrylic polymer may contain an acrylic group. The acrylic group may be bonded as a side chain to the main chain. The acrylic polymer may contain an epoxy group. The epoxy group may be bonded as a side chain to the main chain.

[0154] The chain extender may contain a styrene copolymer. The chain extender may contain styrene glycidyl acrylate.

[0155] The chain extender may be chemically bonded to the biodegradable polyester resin. The chain extender may be chemically bonded to a polymer contained in the biodegradable polyester resin. The chain extender may be bonded to the end of a polymer contained in the biodegradable polyester resin. Further, the chain extender may be bonded to the ends of three polymers contained in the biodegradable polyester resin.

[0156] The chain extender may be a terminal capping agent that caps the ends of the polymer.

[0157] The chain extender may be contained in the biodegradable polyester resin composition according to the examples in an amount of about 0.1 wt% to about 10 wt%. The chain extender may be contained in the biodegradable polyester resin composition according to the examples in an amount of about 0.2 wt% to about 8 wt%. The chain extender may be contained in the biodegradable polyester resin composition according to the examples in an amount of about 0.3 wt% to about 7 wt%.

[0158] When the biodegradable polyester resin composition according to the examples contains the chain extender within the above range, it may have appropriate hydrolysis resistance and appropriate biodegradability.

[0159] Also, the chain extender can react with terminal carboxyl groups or unreacted carboxyl groups. Thereby, the biodegradable polyester resin composition according to the examples may have a low acid value.

[0160] Also, the chain extender can couple the polymers contained in the biodegradable polyester resin, and thereby the proportion of high molecular weight polymers in the biodegradable polyester resin composition according to the examples can be increased. Thereby, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0161] The biodegradable polyester resin composition according to the examples may contain oligomers. The molecular weight of the oligomers may be about 400 to about 1300.

[0162] The oligomer may be included in the biodegradable polyester resin composition according to the examples at about 3000 ppm to about 30000 ppm, based on the total resin composition. The oligomer may be included in the biodegradable polyester resin composition according to the examples at about 5000 ppm to about 20000 ppm, based on the total resin composition. The oligomer may be included in the biodegradable polyester resin composition according to the examples at about 5000 ppm to about 15000 ppm, based on the total resin composition. The oligomer may be included in the biodegradable polyester resin composition according to the examples at about 7000 ppm to about 15000 ppm, based on the total resin composition.

[0163] The oligomer may be a reaction product of at least two or more of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. The oligomer may be a reaction product of 1,4-butanediol, terephthalic acid, and adipic acid.

[0164] The oligomer may include an oligomer in which the molar ratio of the aliphatic dicarboxylic acid is higher than the molar ratio of the aromatic dicarboxylic acid. Among the oligomers, the proportion of the oligomer containing relatively more of the aliphatic dicarboxylic acid may be even higher than the proportion of the oligomer containing relatively more of the aromatic dicarboxylic acid.

[0165] The oligomer may include a first oligomer, a second oligomer, a third oligomer, and a fourth oligomer.

[0166] The first oligomer may have a molecular weight between 415 and 425. The first oligomer may have a molecular weight between 419 and 424.

[0167] The first oligomer may be a reaction product formed by the reaction of two molecules of 1,4-butanediol, one molecule of terephthalic acid, and one molecule of adipic acid. That is, the first oligomer may contain the 1,4-butanediol, the terephthalic acid, and the adipic acid in a molar ratio of 2:1:1. Further, the first oligomer may have four ester bonds. The first oligomer may have a ring structure.

[0168] Further, the first oligomer may contain one first unit represented by Chemical Formula 8 below and one second unit represented by Chemical Formula 9 below.

[0169]

Chemical Formula

[0170]

Chemical Formula

[0171] The first oligomer may have a ring structure. The first oligomer may contain the first unit and the second unit and have a ring structure.

[0172] The first oligomer may be represented by Chemical Formula 10 below.

[0173]

Chemical Formula

[0174] The content of the first oligomer may be about 1000 ppm to about 6000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the first oligomer may be about 1500 ppm to about 5000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the first oligomer may be about 2000 ppm to about 4500 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the first oligomer may be about 2500 ppm to about 5000 ppm based on the whole biodegradable polyester resin composition according to the examples.

[0175] The second oligomer may have a molecular weight between 620 and 630. The second oligomer may have a molecular weight between 621 and 626.

[0176] The second oligomer may be a reaction product formed by the reaction of 3 molecules of 1,4 - butanediol, 1 molecule of terephthalic acid, and 2 molecules of adipic acid. That is, the second oligomer may contain the 1,4 - butanediol, the terephthalic acid, and the adipic acid in a molar ratio of 3:1:2. Further, the second oligomer may have 6 ester bonds.

[0177] The second oligomer may contain 1 unit represented by Chemical Formula 6 and 2 units represented by Chemical Formula 7.

[0178] The second oligomer may be at least one selected from the group consisting of the following Chemical Formula 11, Chemical Formula 12, or Chemical Formula 13.

[0179]

Chemical Formula

[0180]

Chemical Formula

[0181] [Chemical formula]

[0182] The content of the second oligomer may be about 1000 ppm to about 5000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the second oligomer may be about 1200 ppm to about 4500 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the second oligomer may be about 1500 ppm to about 4000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the second oligomer may be about 2000 ppm to about 3800 ppm based on the whole biodegradable polyester resin composition according to the examples.

[0183] The third oligomer may have a molecular weight between 640 and 650. The third oligomer may have a molecular weight between 641 and 645.

[0184] The third oligomer may be a reaction product formed by the reaction of 3 moles of 1,4-butanediol, 2 moles of terephthalic acid and 1 mole of adipic acid. That is, the third oligomer may contain the 1,4-butanediol, the terephthalic acid and the adipic acid in a molar ratio of 3:2:1. Also, the third oligomer may have 6 ester bonds.

[0185] The third oligomer may contain 2 of the first units represented by Chemical formula 6 and 1 of the second units represented by Chemical formula 7.

[0186] The third oligomer may be at least one selected from the group consisting of the following Chemical formula 14, Chemical formula 15 or Chemical formula 16.

[0187] [Chemical formula]

[0188]

Chem.

[0189]

Chem.

[0190] The content of the third oligomer may be about 300 ppm to about 3000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the third oligomer may be about 500 ppm to about 2500 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the third oligomer may be about 700 ppm to about 2000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the third oligomer may be about 800 ppm to about 1800 ppm based on the whole biodegradable polyester resin composition according to the examples.

[0191] The fourth oligomer may have a molecular weight between 840 and 850. The fourth oligomer may have a molecular weight between 841 and 845.

[0192] The fourth oligomer may contain a reaction product formed by the reaction of 4 molecules of 1,4-butanediol, 2 molecules of terephthalic acid and 2 molecules of adipic acid. That is, the fourth oligomer may contain the 1,4-butanediol, the terephthalic acid and the adipic acid in a molar ratio of 4:2:2. Also, the fourth oligomer may have 8 ester bonds.

[0193] The fourth oligomer may contain 2 of the first units represented by Chemical Formula 6 and 2 of the second units represented by Chemical Formula 7.

[0194] Further, the fourth oligomer may contain at least one or more of the following bonding structures.

[0195] 1) First unit - First unit - Second unit - Second unit 2) First unit - Second unit - First unit - Second unit 3) First unit - Second unit - Second unit - First unit 4) Second unit - First unit - First unit - Second unit

[0196] The content of the fourth oligomer may be about 300 ppm to about 3500 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the fourth oligomer may be about 500 ppm to about 3000 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the fourth oligomer may be about 700 ppm to about 2500 ppm based on the whole biodegradable polyester resin composition according to the examples. The content of the fourth oligomer may be about 800 ppm to about 2000 ppm based on the whole biodegradable polyester resin composition according to the examples.

[0197] Based on the whole oligomer, the ratio of the first oligomer (content of the first oligomer / content of the whole oligomer) may be about 0.20 to about 0.5. Based on the whole oligomer, the ratio of the first oligomer may be about 0.25 to about 0.45. Based on the whole oligomer, the ratio of the first oligomer may be about 0.30 to about 0.45. Based on the whole oligomer, the ratio of the first oligomer may be about 0.32 to about 0.43.

[0198] Based on the whole oligomer, the ratio of the second oligomer (content of the second oligomer / content of the whole oligomer) may be about 0.15 to about 0.45. Based on the whole oligomer, the ratio of the second oligomer may be about 0.20 to 0.40. Based on the whole oligomer, the ratio of the second oligomer may be about 0.23 to 0.37. Based on the whole oligomer, the ratio of the second oligomer may be about 0.25 to 0.36.

[0199] Based on the whole oligomer, the ratio of the third oligomer (content of the third oligomer / content of the whole oligomer) may be about 0.05 to about 0.25. Based on the whole oligomer, the ratio of the third oligomer may be about 0.07 to 0.20. Based on the whole oligomer, the ratio of the third oligomer may be about 0.08 to 0.17. Based on the whole oligomer, the ratio of the third oligomer may be about 0.09 to 0.16.

[0200] Based on the whole oligomer, the ratio of the fourth oligomer (content of the fourth oligomer / content of the whole oligomer) may be about 0.05 to about 0.30. Based on the whole oligomer, the ratio of the fourth oligomer may be about 0.07 to 0.25. Based on the whole oligomer, the ratio of the fourth oligomer may be about 0.08 to 0.22. Based on the whole oligomer, the ratio of the fourth oligomer may be about 0.09 to 0.19.

[0201] Based on the first oligomer, the ratio of the second oligomer (content of the second oligomer / content of the first oligomer) may be about 0.5 to about 1.2. Based on the first oligomer, the ratio of the second oligomer may be about 0.55 to about 1.0. Based on the first oligomer, the ratio of the second oligomer may be about 0.6 to about 0.95. Based on the first oligomer, the ratio of the second oligomer may be about 0.7 to about 0.9.

[0202] Based on the first oligomer, the ratio of the third oligomer (content of the third oligomer / content of the first oligomer) may be about 0.2 to about 0.6. Based on the first oligomer, the ratio of the third oligomer may be about 0.22 to about 0.50. Based on the first oligomer, the ratio of the third oligomer may be about 0.23 to about 0.45. Based on the first oligomer, the ratio of the third oligomer may be about 0.25 to about 0.42.

[0203] Based on the first oligomer, the ratio of the fourth oligomer (content of the fourth oligomer / content of the first oligomer) may be about 0.25 to about 0.65. Based on the first oligomer, the ratio of the fourth oligomer may be about 0.27 to about 0.55. Based on the first oligomer, the ratio of the fourth oligomer may be about 0.30 to about 0.50. Based on the first oligomer, the ratio of the fourth oligomer may be about 0.30 to about 0.48.

[0204] The second oligomer may be contained in the oligomer at a content even higher than that of the third oligomer.

[0205] Based on the second oligomer, the ratio of the third oligomer (content of the third oligomer / content of the second oligomer) may be about 0.2 to about 0.6. Based on the second oligomer, the ratio of the third oligomer (content of the third oligomer / content of the second oligomer) may be about 0.24 to about 0.5. Based on the second oligomer, the ratio of the third oligomer (content of the third oligomer / content of the second oligomer) may be about 0.27 to about 0.45.

[0206] The molecular weight and the content of the oligomer can be measured by liquid chromatography mass spectrometry.

[0207] First, the biodegradable polyester resin composition according to the examples, or the biodegradable polyester film according to the examples, is pulverized and classified to produce a powder having an average particle size (D50) of about 50 μm. Then, the powder is immersed in an organic solvent such as acetonitrile at room temperature for about 24 hours. After that, after the supernatant of the organic solvent is sampled, the molecular weight and the content of the oligomer can be measured by the liquid chromatography mass spectrometry. Also, in order to measure the content of the oligomer, a black curve is obtained using dibutyl phthalate as a standard substance.

[0208] The oligomer may be a hydrophilic regulator that can adjust the hydrophilicity and / or hydrophobicity of the biodegradable polyester resin composition according to the examples. Thereby, the oligomer can appropriately adjust the degree of hydrolysis of the biodegradable resin composition according to the examples. The oligomer may be a hydrolysis regulator that appropriately adjusts the degree of hydrolysis of the biodegradable resin composition according to the examples.

[0209] Also, the oligomer can appropriately adjust the biodegradability of the biodegradable resin composition according to the examples. The oligomer may be a biodegradation regulator that appropriately adjusts the biodegradability of the biodegradable resin composition according to the examples.

[0210] Since the biodegradable resin composition according to the examples contains the oligomer within the above range, it may have an appropriate degree of hydrolysis and an appropriate degree of biodegradation. In particular, since the biodegradable resin composition according to the examples contains the first oligomer, the second oligomer, the third oligomer, and the fourth oligomer within the above range, it may have an appropriate degree of hydrolysis and an appropriate degree of biodegradation.

[0211] As described above, the oligomer can adjust the biodegradability of the biodegradable polyester resin composition according to the examples. Thereby, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis and an appropriate degree of biodegradation.

[0212] Since the biodegradable polyester resin composition according to the example contains the oligomer having the above characteristics, it may have a low initial hydrolysis degree, a high late-stage hydrolysis degree, and a high late-stage biodegradation degree.

[0213] Accordingly, the biodegradable polyester resin composition according to the example can be efficiently applied to packaging films and the like. That is, the film produced from the biodegradable polyester resin composition according to the example can be used for ordinary applications such as packaging. At this time, since the biodegradable polyester resin composition according to the example has a low initial hydrolysis degree, within the normal usage period of the user, the biodegradable polyester film can maintain mechanical and chemical physical properties to a certain extent or more.

[0214] Moreover, since the biodegradable polyester resin composition according to the example contains the oligomer having the above characteristics, it may have a high late-stage hydrolysis degree. Accordingly, the film produced from the biodegradable polyester resin composition according to the example may be easily decomposed when discarded after use.

[0215] In addition, since the biodegradable polyester resin composition according to the example contains the oligomer having the above characteristics, the degradation by ambient moisture and the degradation by microorganisms can complement each other. Accordingly, the biodegradable polyester resin composition according to the example may have a low initial hydrolysis degree and a high biodegradation degree.

[0216] In addition, since the biodegradable polyester resin composition according to the examples contains an oligomer having the above characteristics, it may have a biodegradability of 1.5 or more per aliphatic carboxylic acid. That is, the biodegradable polyester resin composition according to the examples has a low content of aliphatic carboxylic acid and a high biodegradability. As a result, since the biodegradable polyester resin composition according to the examples has a relatively high content of aromatic carboxylic acid, it may have high hydrolysis resistance in the initial stage and high biodegradability in the later stage.

[0217] The biodegradable polyester resin composition according to the examples can maintain mechanical and chemical physical properties above a certain level during the user's usage period. At the same time, since the biodegradable polyester resin composition according to the examples has a high degree of later-stage hydrolysis, it may be easily decomposed in a river or the sea. That is, the biodegradable polyester resin composition according to the examples can solve environmental problems such as the marine plastic problem.

[0218] The biodegradable polyester resin composition according to the examples may contain a heat stabilizer. The heat stabilizer may be a phosphorus-based heat stabilizer.

[0219] The heat stabilizer may be at least one selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentamine, triethyl phosphonoacetate, phosphoric acid, phosphorous acid, polyphosphric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, or triphenyl phosphine.

[0220] In addition, the heat stabilizer may be an antioxidant having an antioxidant function.

[0221] The content of the heat stabilizer may be about 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 200 ppm based on the total weight of the biodegradable polyester resin. By the content of the heat stabilizer satisfying the above range, the deterioration of the polymer due to high temperature during the reaction process can be controlled, the end groups of the polymer can be reduced, and the color can be improved. Further, the heat stabilizer can suppress the activation of a titanium-based catalyst or the like and adjust the reaction rate.

[0222] The biodegradable polyester resin composition according to the example may contain an elongation improver. Examples of the elongation improver may include oils such as paraffin oil, naphthenic oil or aromatic oil, or those having adipates such as dibutyl adipate, diethylhexyl adipate, dioctyl adipate or diisopropyl adipate.

[0223] The elongation improver may be contained in the biodegradable polyester resin composition according to the example in an amount of about 0.001 part by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin. The elongation improver may be contained in the biodegradable polyester resin composition according to the example in an amount of about 0.01 part by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0224] Since the elongation improver is contained in the above range, the biodegradable polyester resin composition according to the example may have improved mechanical properties.

[0225] The biodegradable polyester resin composition according to the embodiment may contain an inorganic filler. The inorganic filler may be selected from at least one or more of the group consisting of calcium sulfate, barium sulfate, talc, talcum 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, silicate, mica, glass fiber, or mineral fiber.

[0226] Regarding the inorganic filler, based on the volume in the particle size distribution obtained by the laser diffraction method, the cumulative 50% particle size (D 50 ) may be about 100 μm or less, about 85 μm or less, about 70 μm or less, about 50 μm or less, about 25 μm or less, about 10 μm or less, about 5 μm or less, about 3 μm or less, or about 1 μm or less.

[0227] Also, the specific surface area of the inorganic filler may be about 100 m 2 / g or more. For example, the specific surface area of the inorganic filler may be about 100 m 2 / g or more, about 105 m 2 / g or more, or about 110 m 2 / g or more.

[0228] The inorganic filler may be contained in the biodegradable polyester resin composition according to the embodiment in an amount of about 3 parts by weight to about 50 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The inorganic filler may be contained in the biodegradable polyester resin composition according to the embodiment in an amount of about 5 parts by weight to about 30 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0229] The inorganic filler may be contained in an amount of about 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 about 3,000 ppm or less, about 1,500 ppm or less, about 1,200 ppm or less, about 800 ppm or less, or about 600 ppm or less based on the total weight of the biodegradable polyester resin composition according to the examples, and may also be about 50 ppm or more, about 100 ppm or more, about 130 ppm or more, about 150 ppm or more, or about 180 ppm or more.

[0230] Since the biodegradable polyester resin composition according to the examples contains the inorganic filler in the above content, it may have mechanical properties, appropriate UV resistance, an appropriate biodegradation rate, and an appropriate hydrolysis rate of the biodegradable polyester resin composition according to the examples.

[0231] 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 be a composite resin composition containing two or more types of resins, fillers, and additives.

[0232] At least one or more of the two types of biodegradable resins may be selected from the group consisting of polybutylene azelate terephthalate (PBAzT), polybutylene sebacate terephthalate (PBSeT), polybutylene succinate terephthalate (PBST), polyhydroxyalkanoate (PHA), or polylactic acid (PLA).

[0233] The two biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 10 parts by weight to about 100 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The two biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 10 parts by weight to about 60 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The two biodegradable resins may be included in the biodegradable polyester resin composition according to the examples in an amount of about 20 parts by weight to about 50 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0234] The two biodegradable resins can complement the physical properties, including mechanical, optical, and chemical properties, of the biodegradable polyester resin. Since the biodegradable polyester resin composition according to the examples contains the two biodegradable resins in the above content, it may have mechanical properties, appropriate UV resistance, an appropriate biodegradation rate, and an appropriate hydrolysis rate.

[0235] Also, the number of terminal carboxyl groups in the biodegradable polyester resin composition according to the examples may be about 50 eq / ton or less. For example, the number of terminal carboxyl 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. When the biodegradable polyester resin composition according to the examples is extruded to form a molded product with the number of terminal carboxyl groups adjusted within the above range, deterioration can be prevented, and improved mechanical properties can be realized.

[0236] Also, the intrinsic viscosity (IV) of the biodegradable polyester resin composition according to the examples may be about 0.9 dl / g or more. The intrinsic viscosity of other biodegradable polyester resin compositions in the examples may be about 0.95 dl / g or more, about 1.0 dl / g or more, about 1.1 dl / g or more, about 1.2 dl / g or more, or about 1.3 dl / g or more. The intrinsic viscosity of the biodegradable polyester resin composition according to the examples may be about 0.95 dl / g to about 1.7 dl / g. The intrinsic viscosity of the biodegradable polyester resin composition according to the examples may be about 1.3 dl / g to about 1.7 dl / g. The intrinsic viscosity of the biodegradable polyester resin composition according to the examples may be about 1.4 dl / g to about 1.7 dl / g.

[0237] The process of manufacturing the biodegradable polyester resin composition according to the examples is as follows.

[0238] Referring to FIG. 1, the manufacturing apparatus of the biodegradable polyester resin includes a slurry stirrer 100, an esterification reaction section 200, a polycondensation reaction section 300, a post-treatment section 400, a first recovery section 510, and a second recovery section 520.

[0239] The manufacturing method of the biodegradable polyester resin includes the step of manufacturing a slurry containing the diol and the aromatic dicarboxylic acid.

[0240] The step of manufacturing the slurry includes the step of mixing and treating the diol and the aromatic dicarboxylic acid. That is, the step of manufacturing the slurry may be a pretreatment step before the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid and slurrying them.

[0241] 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, when the diol is 1,4-butanediol, the temperature of the slurry may be about 35°C to about 45°C.

[0242] The diol and the aromatic dicarboxylic acid can be put into the slurry stirrer 100 and stirred to produce the slurry.

[0243] By mixing and pre-treating the diol and the aromatic dicarboxylic acid to form a slurry, not only can the diol and the aromatic dicarboxylic acid react uniformly, but it is also effective in promptly carrying out the esterification reaction rate, so the reaction efficiency can be enhanced.

[0244] In particular, when the aromatic dicarboxylic acid has complete crystallinity and is in powder form like terephthalic acid, its solubility in the diol is very low, and a homogeneous reaction may not easily occur. Therefore, the pre-treatment process of forming the slurry plays a very important role in enhancing the reaction efficiency by providing a biodegradable polyester resin, sheet, film, and molded product having excellent physical properties according to embodiments of the present invention.

[0245] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid has complete crystallinity, is a white crystal that sublimes at nearly 300 °C under normal pressure without a melting point, and has a very low solubility in the diol. Therefore, when a pre-treatment process is carried out before the esterification reaction, the surface area can be increased by reacting with the diol within the solid matrix of terephthalic acid, and a uniform reaction can be induced.

[0246] Also, when the aromatic dicarboxylic acid is dimethyl terephthalate, the pre-treatment process can melt the dimethyl terephthalate at about 142 °C to 170 °C and react it with the diol, so that the esterification reaction rate can be made even faster and more efficient.

[0247] On the other hand, in the pre-treatment stage of manufacturing the slurry, the structure and physical properties of the biodegradable polyester resin may vary depending on the particle size, particle size distribution, pre-treatment reaction conditions, etc. of the aromatic dicarboxylic acid.

[0248] For example, the aromatic dicarboxylic acid includes terephthalic acid, and the terephthalic acid has an average particle size (D50) measured by a particle size analyzer Microtrac S3500 in a particle size distribution (PSD) of 10 μm to 400 μm, and the standard deviation with respect to the average particle size (D50) may be 100 or less. The standard deviation means the square root of the dispersion. The average particle size (D50) of the terephthalic acid may be 20 μm to 200 μm, for example, 30 μm to 200 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 more advantageous in terms of improving the solubility in diol and the reaction rate.

[0249] In the pretreatment step, the diol and the aromatic dicarboxylic acid can be mixed and put into the slurry stirrer 100 (tank).

[0250] The slurry stirrer 100 is, for example, of an anchor type at the lowermost part, the height to the agitator is 20 mm or more, and it may be more advantageous to achieve an efficient stirring effect by being provided with two or more rotating blades.

[0251] For example, the slurry stirrer 100 may have a height to the agitator of 20 mm or more, that is, there may be substantially a connection between the reactor and the lowermost part of the agitator. In this case, a slurry can be obtained without precipitation. If the pattern, form, and rotating blades of the agitator do not satisfy the above conditions, when the diol and the aromatic dicarboxylic acid are initially mixed, the aromatic dicarboxylic acid may settle to the bottom, and in this case, phase separation may occur.

[0252] The pretreatment step of manufacturing the slurry may include a step of mixing the diol and the aromatic dicarboxylic acid and stirring at about 30 °C to about 100 °C, at about 50 rpm to about 200 rpm, for 10 minutes or more, for example, 10 minutes to 200 minutes.

[0253] The diol may have the same characteristics as described above.

[0254] The diol can be charged all at once or in portions. For example, the diol can be charged separately when mixing with the aromatic dicarboxylic acid and when mixing with the aliphatic dicarboxylic acid.

[0255] The aromatic dicarboxylic acid may have the same characteristics as described above.

[0256] In the pretreatment stage of manufacturing 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 stage of manufacturing 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 stage of manufacturing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid may be about 1.2:1 to about 1.5:1.

[0257] When the diol is charged in an amount even more than the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be easily dispersed.

[0258] Also, an additive can 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 a solution.

[0259] The method for manufacturing the biodegradable polyester resin mixes a diol and an aromatic dicarboxylic acid, esterifies using the slurry obtained by pretreatment to obtain a prepolymer, and subjecting the prepolymer to a polycondensation reaction, thereby efficiently achieving the structure and physical properties of the biodegradable polyester resin targeted by the embodiments of the present invention.

[0260] The method for producing the biodegradable polyester resin includes a step of subjecting the slurry and the aliphatic dicarboxylic acid to an esterification reaction to produce a prepolymer. The slurry and the aliphatic dicarboxylic acid can react in the ester reaction section.

[0261] In the esterification reaction, by using the slurry, the reaction time can be shortened. For example, the slurry obtained in the pretreatment step can shorten the reaction time of the ester reaction by 1.5 times or more.

[0262] The esterification reaction can be carried out at least once or more.

[0263] In one embodiment, the esterification reaction can be carried out once after adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid to the slurry. That is, the slurry is charged into the esterification reactor, and the aliphatic dicarboxylic acid alone, or the aliphatic dicarboxylic acid and the diol are charged into the esterification reactor, and the esterification reaction can be carried out.

[0264] The diol and the aliphatic dicarboxylic acid may be added to the slurry containing the aromatic dicarboxylic acid in a slurry state.

[0265] The esterification reaction can be carried out at about 250 °C or lower for about 0.5 hour to about 6 hours. Specifically, the esterification reaction can be carried out at about 180 °C to about 250 °C, about 185 °C to about 240 °C or about 200 °C to about 240 °C under normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the esterification reaction can be carried out for 0.5 hour to 5.5 hours, 0.5 hour to 4.5 hours or 1 hour to 4 hours, but is not limited thereto.

[0266] In the esterification reaction, the total number of moles of diol charged 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 charged 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.

[0267] Also, the temperature of the slurry of the diol and the aliphatic dicarboxylic acid may be about 5 °C to about 15 °C higher than the melting point of the diol.

[0268] Also, various additives such as the nanocellulose may be added to the slurry of the diol and the aliphatic dicarboxylic acid.

[0269] In one embodiment, the first esterification reaction can be carried out with the slurry itself or after the diol is added to the slurry. Also, after the first ester reaction, the aliphatic dicarboxylic acid or a mixture of the aliphatic dicarboxylic acid and the diol is charged into the ester reaction section, and the second ester reaction can be carried out together with the first ester reaction product.

[0270] The first esterification reaction can be carried out at 250 °C or lower for 0.25 hours 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 normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the first esterification reaction can be carried out for 0.25 hours to 4 hours, 0.25 hours to 3.5 hours or 1.5 hours to 3 hours, but is not limited thereto.

[0271] The second ester reaction can be carried out at about 250°C or lower for 0.25 hours 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 normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the second esterification reaction can be carried out for 0.5 hours to 3 hours, 1 hour to 2.5 hours, or 1.5 hours to 3 hours, but is not limited thereto.

[0272] In the first ester reaction and the second ester reaction, the reaction temperature and reaction time may be adjusted respectively to adjust the number ratio of the first block and the second block, etc. Further, when the ester reaction is carried out separately into the first ester reaction and the second ester reaction, the overall ester reaction can be precisely controlled. Thereby, when the ester reaction is carried out separately, the reaction stability and reaction uniformity of the ester reaction can be improved.

[0273] After the second ester reaction is completed, a third ester reaction can be carried out. At this time, a monomer composition containing at least one or more of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid is added to the second ester reaction product, and the third ester reaction can be carried out.

[0274] The monomer composition may be added to the second ester reaction product in a content of about 0.5 parts by weight to about 5 parts by weight based on 100 parts by weight of the second ester reaction product.

[0275] Also, in the monomer composition, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be about 1:1 to about 1:3. In the monomer composition, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be about 1:1.3 to about 1:3.

[0276] Further, in the monomer composition, the molar ratio of the diol to the total dicarboxylic acid may be about 0.8:1 to 1:1.2.

[0277] The third esterification reaction can be carried out at about 250 °C or lower for 0.1 hour to 0.5 hour. Specifically, the third esterification reaction can be carried out at 180 °C to 250 °C, 185 °C to 240 °C or 200 °C to 240 °C under normal pressure or reduced pressure. For example, although the third esterification reaction can be carried out for 5 minutes to 40 minutes, 10 minutes to 30 minutes or 10 minutes to 20 minutes, it is not limited thereto.

[0278] The prepolymer can be formed by the third esterification reaction.

[0279] When the third esterification reaction is carried out under the above process conditions using the monomer composition as described above, the content of the oligomer can be appropriately adjusted.

[0280] Differently, the oligomer can be separately produced and added to the second esterification reaction product to produce the prepolymer.

[0281] In the third esterification reaction, the second esterification reaction product may not be used. That is, the third esterification reaction can be carried out with the monomer composition and other additive substances such as a catalyst. Then, the second esterification reaction product and the third esterification reaction product can be mixed with each other to produce the prepolymer. At this time, the third esterification reaction product can be mixed with the second esterification reaction product in a content of about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the second esterification reaction product to produce the prepolymer.

[0282] The number-average molecular weight of the prepolymer may be about 500 to about 10,000 g / mol. For example, the number-average molecular weight of the prepolymer may be about 500 to about 8,500 g / mol, about 500 to about 8,000 g / mol, about 500 to about 7,000 g / mol, about 500 g / mol to about 5,000 g / mol, or about 1,500 g / mol to about 4,000 g / mol. By the number-average molecular weight of the prepolymer satisfying the above range, the molecular weight of the polymer in the polycondensation reaction can be efficiently increased.

[0283] The number-average molecular weight can be measured using gel permeation chromatography (GPC). Specifically, the data calculated by gel permeation chromatography has various items such as Mn, Mw, and Mp, and among these, the molecular weight can be measured based on the number-average molecular weight (Mn).

[0284] The reinforcing material, the branching agent, and / or the metal salt can be added together with the slurry before the esterification reaction. The reinforcing material, the branching agent, and / or the metal salt may be added to the esterification reaction section 200 during the esterification reaction. The reinforcing material, the branching agent, and / or the metal salt may be added to the ester reaction product after the esterification reaction. Also, the reinforcing material, the branching agent, and / or the metal salt may be added together with the aliphatic dicarboxylic acid. Further, the reinforcing material, the branching agent, and / or the metal salt may be added to the esterification reaction section 200 after the first ester reaction and before the second ester reaction.

[0285] Since the reinforcing material and / or the metal salt are added to the esterification reaction, the reinforcing material and / or the metal salt may be uniformly dispersed in the biodegradable polyester resin.

[0286] The reinforcing material may have the characteristics described above. In particular, the nanocellulose can be used as the reinforcing material.

[0287] The nanocellulose may be pretreated by a bead mill, by ultrasonic waves, or by high-speed dispersion at about 1000 rpm to about 1500 rpm before being introduced. Specifically, the nanocellulose may be bead mill-pretreated or ultrasonically pretreated with water-dispersed nanocellulose.

[0288] First, the bead mill pretreatment can be performed with a vertical mill or a horizontal mill as a wet milling device. Although the horizontal mill is preferable in that it can hold a larger amount of beads inside the chamber, reduces mechanical uneven wear, reduces bead wear, and is easy to maintain, it is not limited thereto.

[0289] The bead mill pretreatment can be performed using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0290] Specifically, the bead mill pretreatment can be performed using beads having a diameter of about 0.3 mm to about 1 mm. For example, the diameter of the beads may be about 0.3 mm to about 0.9 mm, about 0.4 mm to about 0.8 mm, about 0.45 mm to about 0.7 mm, or about 0.45 mm to about 0.6 mm.

[0291] By having the bead diameter satisfy the above range, the dispersibility of the nanocellulose can be further improved. If the bead diameter exceeds the above range, the average particle size and particle size deviation of the nanocellulose may increase, resulting in lower dispersibility.

[0292] In addition, it is preferable to use beads with a specific gravity higher than that of nanocellulose in the bead mill pretreatment, because sufficient energy can be transmitted. 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 the water-dispersed nanocellulose. Zirconium beads with a specific gravity four times or more higher than that of the water-dispersed nanocellulose are preferable, but not limited thereto.

[0293] In addition, the ultrasonic pretreatment is a method of physically closing or pulverizing nanoparticles by waves generated by emitting ultrasonic waves of 20 kHz into a solution.

[0294] The ultrasonic pretreatment can be performed at an output of 30,000 J / s or less for a time of 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 a time of 25 minutes or less, 20 minutes or less, or 18 minutes or less. By satisfying the above ranges for the output and the implementation time, the effect of the ultrasonic pretreatment, that is, the improvement of dispersibility, can be maximized. If the amount of energy exceeds the above range, on the contrary, the nanoparticles may re-aggregate and the dispersibility may be lowered.

[0295] The nanocellulose according to the embodiment may be subjected to bead mill pretreatment or ultrasonic pretreatment. Alternatively, the nanocellulose according to the embodiment may be subjected to both bead mill pretreatment and ultrasonic pretreatment. At this time, it is preferable to perform the ultrasonic pretreatment after the bead mill pretreatment in terms of preventing re-aggregation and improving dispersibility.

[0296] Since the nanocellulose contains ionically bonded metal, its dispersibility in water is very high. In addition, a water dispersion liquid with a very high degree of dispersion of the nanocellulose can be obtained by the bead mill pretreatment and / or the ultrasonic pretreatment. In the nanocellulose aqueous dispersion, the content of the nanocellulose may be about 1 wt% to about 50 wt%.

[0297] 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.

[0298] Also, before the first esterification reaction, the titanium-based catalyst and / or the germanium-based catalyst may be added to the slurry, and the titanium-based catalyst and / or the germanium-based catalyst may be further added to the product of the first esterification reaction.

[0299] The biodegradable polyester resin may contain one or more titanium-based catalysts selected from the group consisting of titanium isopropoxide, antimony trioxide, dibutyltin oxide, 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.

[0300] Also, the content of the catalyst may be about 100 ppm to 1000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. For example, it may contain a titanium-based catalyst or a germanium-based catalyst of about 100 ppm to about 800 ppm, about 150 ppm to about 700 ppm, about 200 ppm to about 600 ppm, or about 250 ppm to about 950 ppm. By satisfying the above range of the catalyst content, the physical properties can be further improved.

[0301] Alternatively, the heat stabilizer may be introduced together with the slurry before the esterification reaction. The heat stabilizer may be introduced into the esterification reaction section 200 during the esterification reaction. The heat stabilizer may be introduced into the ester reaction product after the esterification reaction. Further, the heat stabilizer may be introduced together with the aliphatic dicarboxylic acid. Also, the heat stabilizer may be introduced into the esterification reaction section 200 after the first ester reaction and before the second ester reaction.

[0302] The characteristics of the heat stabilizer may be the same as those described above.

[0303] 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 200 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By the content of the heat stabilizer satisfying the above range, deterioration of the polymer due to high temperature during the reaction process can be controlled, the end groups of the polymer can be reduced, and the color can be improved.

[0304] After the esterification reaction is completed, one or more selected from the group consisting of additives such as 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 additive and / or color corrector may be added and stabilized, and then the polycondensation reaction can be carried out. The additive and / or the color corrector may be added after the esterification reaction is completed and introduced into the polycondensation reaction section 300 together with the prepolymer. Thereby, the additive and / or the color corrector may be uniformly dispersed in the biodegradable polyester resin.

[0305] Also, after the esterification reaction is completed, the inorganic filler may be added to the esterification reaction product. That is, after the esterification reaction is completed, after the inorganic filler is introduced and stabilized, the polycondensation reaction can be carried out. The characteristics of the inorganic filler are as described above. The inorganic filler can be introduced into the polycondensation reaction section 300 together with the prepolymer to carry out the polycondensation step. Thereby, the inorganic filler may be uniformly dispersed in the biodegradable polyester resin.

[0306] Also, the first recovery section 510 recovers reaction by-products such as water from the esterification reaction section 200. The first recovery section 510 can recover the by-products generated in the esterification reaction by applying a vacuum pressure to the esterification reaction section 200 or performing reflux.

[0307] The method for producing the biodegradable polyester resin includes a step of subjecting the prepolymer to a polycondensation reaction. The polycondensation reaction can be carried out as follows.

[0308] The prepolymer is introduced into the polycondensation reaction section 300. Also, at least one or more of the reinforcing material, the heat stabilizer, the color corrector, the inorganic filler, the metal salt, or other additives may be introduced into the polycondensation reaction section 300 together with the prepolymer.

[0309] Also, the prepolymer and the oligomer composition are introduced into the polycondensation reaction section, and the polycondensation reaction of the prepolymer and the oligomer can be carried out.

[0310] The oligomer composition may be produced by the following method.

[0311] The oligomer composition can be produced by an esterification reaction of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. At this time, the oligomer composition may be produced to contain, as a main component, an oligomer having a molecular weight of 400 to 1300.

[0312] The temperature of the esterification reaction for producing the oligomer composition may be about 200°C to about 250°C. Also, the esterification reaction time for producing the oligomer composition may be about 5 minutes to about 20 minutes.

[0313] Further, the content of the oligomer composition charged into the polycondensation reaction may be about 0.5 wt% to about 10 wt% based on the total weight charged into the polycondensation reaction. The content of the oligomer composition charged into the polycondensation reaction may be about 1 wt% to about 7 wt% based on the total weight charged into the polycondensation reaction.

[0314] Since the characteristics and content of the oligomer composition are as described above, the biodegradable polyester resin composition according to the examples may contain the oligomer having a molecular weight of 400 to 1300 at an appropriate content.

[0315] Thereafter, the polycondensation reaction can be carried out at about 180°C to about 280°C and about 10 torr or less for about 1 hour to about 5 hours. For example, the polycondensation reaction can be carried out at about 190°C to about 270°C, about 210°C to about 260°C, or about 230°C to about 255°C, and can be carried out at about 0.9 torr or less, about 0.7 torr or less, about 0.2 torr to about 10 torr, about 0.2 torr to about 0.9 torr, or about 0.2 torr to about 0.6 torr, and can be carried out for about 1.5 hours to about 5 hours, about 2 hours to about 5 hours, or about 2.5 hours to about 4.5 hours.

[0316] Also, the polycondensation reaction may include a primary polycondensation and a secondary polycondensation.

[0317] For example, the primary polycondensation can be carried out at about 260 °C or lower, about 250 °C or lower, about 215 °C to about 250 °C, about 215 °C to about 245 °C, or about 230 °C to about 245 °C, at about 1 torr to about 200 torr, about 2 torr to about 100 torr, about 4 torr to about 50 torr, about 5 torr to about 45 torr, or about 8 torr to about 32 torr, for about 0.5 hours to about 3.5 hours, about 0.5 hours to about 3.0 hours, or about 0.5 hours to about 2.8 hours.

[0318] Further, the secondary polycondensation can be carried out at about 220 °C to about 265 °C, about 230 °C to about 260 °C, or about 235 °C to about 255 °C, at about 1 torr or lower, about 0.8 torr or lower, about 0.6 torr or lower, about 0.1 torr to about 1 torr, about 0.2 torr to about 0.8 torr, or about 0.2 torr to about 0.6 torr, for about 0.5 hours to about 4 hours, about 1 hour to about 3.5 hours, or about 1.5 hours to about 3.5 hours.

[0319] Also, before the polycondensation reaction, a titanium-based catalyst or a germanium-based catalyst may be further added to the prepolymer. Further, before the polycondensation reaction, one or more selected from the group consisting of additives such as silica, potassium, or magnesium; amine-based stabilizers such as trimethyl phosphate, triphenyl phosphate, trimethyl phosphine, phosphoric acid, phosphorous acid, or tetraethylenepentamine; and polymerization catalysts such as antimony trioxide, antimony trioxide, or tetrabutyl titanate can be further added to the prepolymer.

[0320] The number average molecular weight of the polymer may be about 30,000 g / mol or more. For example, the number average molecular weight of the polymer may be about 33,000 g / mol or more, about 45,000 g / mol or more, or about 30,000 g / mol to about 90,000 g / mol. By the number average molecular weight of the polymer satisfying the above range, physical properties, impact resistance, durability, and moldability can be further improved.

[0321] Further, the second recovery unit 520 recovers reaction by-products such as water from the polycondensation reaction unit 300. The second recovery unit 520 can apply a vacuum pressure to the polycondensation reaction unit 300 to recover the by-products generated in the polycondensation reaction.

[0322] The second recovery unit 520 can apply a vacuum pressure of about 0.1 torr to about 1 torr inside the polycondensation reaction unit 300. The second recovery unit 520 can apply a vacuum pressure of about 0.1 torr to about 0.9 torr inside the polycondensation reaction unit 300.

[0323] Thereafter, the hydrolysis-resistant agent and / or the chain extender are added to the polymer. Thereafter, the polymer, the hydrolysis-resistant agent, and the chain extender are uniformly mixed and maintained at a temperature of about 200°C to about 260°C for about 1 minute to about 15 minutes. As a result, the polymer comes to react with the hydrolysis-resistant agent and / or the chain extender.

[0324] Alternatively, the hydrolysis-resistant agent and / or the chain extender may be added to the polycondensation reaction unit 300 by a static mixer and reacted with the polymer. The reaction temperature of the hydrolysis-resistant agent and / or the chain extender in the polycondensation reaction unit 300 may be about 200°C to about 260°C. Also, the reaction time of the hydrolysis-resistant agent and / or the chain extender in the polycondensation reaction unit 300 may be about 1 minute to about 15 minutes.

[0325] The hydrolysis-resistant agent may have the same characteristics as described above.

[0326] The chain extender may have the same characteristics as described above.

[0327] As a result, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis and a high degree of biodegradability.

[0328] Thereafter, pellets can be produced from the polymer.

[0329] Specifically, after cooling the polymer to about 15°C or lower, about 10°C or lower, or about 6°C or lower, the cooled polymer can be cut to produce pellets. In contrast, the polymer can be cut at a temperature of about 40°C to about 60°C.

[0330] The cutting step can be carried out without limitation using a pellet cutting machine used in the industry, and the pellets may have various shapes. The pellet cutting method may include an underwater cutting method or a strand cutting method.

[0331] The pellets can undergo further post-treatment processes. The pellets can be introduced into the post-treatment unit 400 to perform the post-treatment process.

[0332] 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.

[0333] The post-treatment process temperature may be about 230°C to about 270°C. The post-treatment process temperature may be about 230°C to about 260°C. The post-treatment process temperature may be about 240°C to about 265°C. The post-treatment process temperature may be about 240°C to about 260°C.

[0334] The post-treatment process time may be about 30 seconds to about 3 minutes. The post-treatment process time may be about 50 seconds to about 2 minutes. The post-treatment process time may be about 1 minute to about 2 minutes.

[0335] Thereafter, the resin extruded by the extruder may be cooled, cut, and processed into post-treated pellets. That is, the resin extruded from the extruder may be reprocessed into pellets by the above-described cutting step.

[0336] The crystallinity of the pellets can be improved in the post-treatment step. Also, the content of residues contained in the pellets can be adjusted in the post-treatment step. In particular, the content of oligomers contained in the pellets can be adjusted by the post-treatment step. The content of residual solvents contained in the pellets can be adjusted by the post-treatment step.

[0337] Thereby, the post-treatment step can appropriately adjust the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable polyester resin.

[0338] The characteristics and content of the oligomers can vary depending on the esterification reaction, the chain extension reaction, the post-treatment step, and the like.

[0339] After the pellets are manufactured, the biodegradable polyester resin can be compounded with the two biodegradable resins. Also, at least one of the inorganic filler, the light stabilizer, the color corrector, the elongation improver, or the other additives can be compounded with the biodegradable polyester resin and the two biodegradable resins.

[0340] The compounding step is as follows.

[0341] The biodegradable polyester resin and the two biodegradable resins are mixed with at least one or more of the inorganic filler, the heat stabilizer, the color corrector, the metal salt, or the other additives, and then fed into an extruder. The mixed biodegradable polyester resin composition melts at a temperature of about 120°C to about 260°C in the extruder and mixes with each other. Then, the melt-mixed biodegradable polyester resin composition is extruded, cooled, cut, and re-pelletized. Through such a process, the two biodegradable resins can be compounded to produce the biodegradable polyester resin composition according to the examples.

[0342] A biodegradable polyester film can be produced with the biodegradable polyester resin according to the examples.

[0343] The thickness of the biodegradable polyester film may be about 5 μm to about 300 μm. For example, the thickness of the biodegradable polyester film may be about 5 μm to about 180 μm, about 5 μm to about 160 μm, about 10 μm to about 150 μm, about 15 μm to about 130 μm, about 20 μm to about 100 μm, about 25 μm to about 80 μm, or about 25 μm to about 60 μm.

[0344] The biodegradable polyester film according to the examples may have a hydrolysis degree and a biodegradation degree substantially the same as those of the biodegradable polyester resin composition described above.

[0345] On the other hand, the biodegradable polyester film can be produced using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0346] Specifically, the method for manufacturing the biodegradable polyester film may include the step of manufacturing the biodegradable resin composition according to the examples and the step of drying and melt-extruding the biodegradable resin composition.

[0347] In the step of drying and melt-extruding the biodegradable polyester resin composition, the drying can be carried out at about 60°C to about 100°C for about 2 hours to about 12 hours. Specifically, the drying can be carried out at about 65°C to about 95°C, about 70°C to about 90°C or about 75°C to about 85°C for about 3 hours to about 12 hours or about 4 hours to about 10 hours. By satisfying the above range of the drying process conditions of the pellets, the quality of the produced biodegradable polyester film or molded article can be further improved. The moisture content of the biodegradable polyester resin composition after the drying step may be about 500 ppm or less based on the total weight of the biodegradable polyester resin composition.

[0348] In the step of drying and melt-extruding, the melt-extrusion can be carried out at a temperature of about 250°C or lower. For example, the melt-extrusion can be carried out at a temperature of about 245°C or lower, about 220°C or lower, about 215°C or lower, about 100°C to about 250°C, about 120°C to about 245°C, or about 130°C to about 215°C. The melt-extrusion can be carried out in a blown film process.

[0349] Biodegradable polyester molded article A biodegradable polyester molded article can be produced using the biodegradable polyester resin.

[0350] Specifically, the molded article can be produced by molding the biodegradable polyester resin composition by a known method in the art such as extrusion and injection. The molded article may be, but is not limited to, an injection molded article, an extrusion molded article, a thin film molded article, a blow molding or blow molded article, a 3D filament, an interior building material, etc.

[0351] For example, the molded article may be in the form of a film or sheet used for agricultural mulching films, disposable gloves, disposable films, disposable envelopes, food packaging materials, metered garbage bags, etc., or may be in the form of fibers used for woven fabrics, knitted fabrics, non-woven fabrics, ropes, etc. Further, as shown in FIG. 2, the molded article may be in the form of a disposable container used for food packaging containers such as lunch boxes. Further, the molded article may be molded articles in various forms such as disposable straws, spoons and chopsticks, food plates, forks, etc.

[0352] In particular, since the molded article can be formed of the biodegradable polyester resin which can improve not only physical properties such as impact absorption energy and hardness but also particularly impact resistance and durability, it can exhibit excellent characteristics when applied to packaging materials for products stored and transported at low temperatures, interior materials for automobiles requiring durability, garbage bags, mulching films, and disposable products.

[0353] The biodegradable polyester resin composition according to the example can measure the degree of biodegradation by the following method.

[0354] In order to measure the degree of biodegradation, the biodegradable resin composition according to the example was mixed with compost, and a biodegradation acceleration test was carried out at a temperature of 60 ° C and a humidity of 90%. 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 biodegradation was derived from the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain period by the initial number average molecular weight.

[0355] The degree of biodegradation may be represented by the following mathematical formula 1.

[0356] [Mathematical formula 1] JPEG2025517982000020.jpg16158

[0357] Here, the biodegradable polyester resin composition according to the example is mixed with compost and undergoes a biodegradation acceleration test at a temperature of 60°C and a humidity of 90% for a certain period. Before the biodegradation acceleration test is conducted, the initial number average molecular weight of the biodegradable polyester resin composition and the number average molecular weight after biodegradation of the biodegradable polyester resin composition that has undergone the biodegradation acceleration test for a certain period are measured by gel permeation chromatography (GPC).

[0358] The biodegradability was derived from the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain period by the initial number average molecular weight.

[0359] Also, the compost may contain about 40 wt% of pig manure, about 15 wt% of chicken manure, about 37 wt% of large sawdust, about 5 wt% of zeolite, and about 3 wt% of a microbial preparation.

[0360] Also, the manufacturer of the compost may be Taeheung F&G, and the product name of the compost may be Jisheng Soil (by-product fertilizer grade 1 compost).

[0361] Also, when the biodegradability is measured, the biodegradable polyester resin composition according to the example is manufactured into a sheet having a thickness of about 300 μm. Thereafter, the manufactured sheet is cut into a size of about 30 mm × 30 mm to produce flakes. The flakes can be mixed with the compost to conduct the biodegradation acceleration test.

[0362] In the biodegradable polyester resin composition according to the example, the biodegradability after 1 week may be about 40% to about 70%. In the biodegradable polyester resin composition according to the example, the biodegradability after 1 week may be about 45% to about 65%. In the biodegradable polyester resin composition according to the example, the biodegradability after 1 week may be about 47% to about 63%. In the biodegradable polyester resin composition according to the example, the biodegradability after 1 week may be about 49% to about 62%.

[0363] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 2 weeks may be about 50% to about 70%. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 2 weeks may be about 55% to about 68%.

[0364] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 3 weeks may be about 63% to about 75%. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 3 weeks may be about 63% to about 73%.

[0365] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 4 weeks may be about 73% to about 85%. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 4 weeks may be 75% to 82%.

[0366] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 6 weeks may be about 80% to about 90%. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 6 weeks may be about 82% to about 88%.

[0367] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 85% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 87% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 88% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 89% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 90% or more.

[0368] In the biodegradable polyester resin composition according to the example, the rate of increase in biodegradability from 1 week to 2 weeks may be about 4% / week to about 15% / week. In the biodegradable polyester resin composition according to the example, the rate of increase in biodegradability from 1 week to 2 weeks may be about 5% / week to about 13% / week.

[0369] The biodegradable polyester resin composition according to the example can be measured for the degree of hydrolysis by the following method.

[0370] In order to measure the degree of hydrolysis, the biodegradable resin composition according to the example is immersed in water at 80°C (100% RH), and then a hydrolysis acceleration test is carried out. After a certain period of time has passed, the number average molecular weight of the biodegradable polyester resin composition according to the example is measured using gel permeation chromatography (GPC). The degree of hydrolysis was derived as the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after hydrolysis for a certain period of time by the initial number average molecular weight.

[0371] The degree of hydrolysis may be represented by the following formula 2.

[0372] [Formula 2] JPEG2025517982000021.jpg15153

[0373] Here, the biodegradable polyester resin composition according to the example is immersed in water at 80°C and then undergoes a hydrolysis acceleration test for a certain period of time. Before the hydrolysis acceleration test is carried out, the initial number average molecular weight of the biodegradable polyester resin composition and the number average molecular weight after hydrolysis of the biodegradable polyester resin composition that has undergone the hydrolysis acceleration test for a certain period of time are measured by gel permeation chromatography (GPC).

[0374] The degree of hydrolysis was derived as the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after hydrolysis for a certain period of time by the initial number average molecular weight.

[0375] Also, when the degree of hydrolysis is measured, the biodegradable polyester resin composition according to the examples is produced into a sheet having a thickness of about 300 μm. Thereafter, the produced sheet is cut into a size of about 30 mm × 30 mm to produce flakes. The flakes can be immersed in the warm water to perform the hydrolysis acceleration test.

[0376] 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%.

[0377] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after two weeks may be about 80% to about 93%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after two weeks may be about 85% to about 92%.

[0378] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after three weeks may be about 90% to about 97%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after three weeks may be about 91% to about 96%.

[0379] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after four weeks may be about 92% to about 99%. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after four weeks may be about 93% to about 97%.

[0380] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after six weeks may be about 94% or more. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after six weeks may be about 95% or more.

[0381] 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.

[0382] In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 25% / week to about 50% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 29% / week to about 50% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 30% / week to about 45% / week.

[0383] Since the biodegradable polyester resin composition according to the examples has a degree of hydrolysis and a rate of increase in the degree of hydrolysis within the above ranges, the biodegradable polyester resin composition according to the examples may have appropriate durability in the area of daily life and may be easily hydrolyzed at the time of disposal. That is, since the biodegradable polyester resin composition according to the examples has a degree of hydrolysis and a rate of increase in the degree of hydrolysis within an appropriate range, it may have sufficient hydrolysis resistance when used for an appropriate period in disposable packaging, etc. Further, the biodegradable polyester resin composition according to the examples may be easily decomposed by hydrolysis and biodegradation after sufficient time has passed when discarded not only in the soil but also in a river or the sea, etc.

[0384] In the biodegradable polyester resin composition according to the examples, the degree of biodegradation per aliphatic carboxylic acid may be about 1.5 or more. Further, the degree of biodegradation per aliphatic carboxylic acid may be about 1.65 or more. The degree of biodegradation per aliphatic carboxylic acid may be about 1.75 or more. The degree of biodegradation per aliphatic carboxylic acid may be about 1.8 or more. The degree of biodegradation per aliphatic carboxylic acid may be about 1.85 or more. The degree of biodegradation per aliphatic carboxylic acid may be about 1.90 or more. The maximum value of the degree of biodegradation per aliphatic carboxylic acid may be about 4.

[0385] The biodegradability per aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the ratio of the aliphatic carboxylic acid based on the total dicarboxylic acids. The biodegradability per aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the ratio of the mol% of the aliphatic carboxylic acid based on the total dicarboxylic acids.

[0386] The biodegradability per aliphatic carboxylic acid may be represented by the following formula (3).

[0387] [Formula (3)] JPEG2025517982000022.jpg13157

[0388] The composition of the biodegradable polyester resin such as the number of the first blocks, the number of the second blocks, the content of the aliphatic dicarboxylic acid or the content of the aromatic dicarboxylic acid, the process conditions for producing the biodegradable polyester resin, the reinforcing material, the metal salt, the hydrolysis-resistant agent, the chain extender, the oligomer, or the heat stabilizer, etc. are appropriately adjusted so that the biodegradability per aliphatic carboxylic acid may be within the above range.

[0389] Also, the acid value of the biodegradable polyester resin composition according to the examples may be about 0.01 mgKOH / g to about 3 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be about 0.1 mgKOH / g to about 2.5 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be about 0.1 mgKOH / g to about 2.3 mgKOH / g.

[0390] The biodegradable polyester resin composition according to the examples may have hydrolysis degree characteristics and biodegradability characteristics as described above because it has an acid value within the above range.

[0391] In addition, the biodegradable polyester resin composition according to the examples may contain a nitrogen element. The nitrogen element may be derived from the metal salt and / or the chain extender, etc. The content of the nitrogen element may be about 0.1 ppm to about 500 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be about 1 ppm to about 400 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be about 1 ppm to about 300 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples.

[0392] In addition, the biodegradable polyester resin composition according to the examples may contain a silicon element. The silicon element may be derived from the hydrolysis-resistant agent, etc. The content of the silicon element may be about 0.1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon element may be about 0.5 ppm to about 90 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon element may be about 1 ppm to about 80 ppm based on the biodegradable polyester resin composition according to the examples. The content of the silicon element may be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0393] In addition, 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 100 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 90 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 80 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.

[0394] In addition, the biodegradable polyester resin composition according to the examples may have surface tension, water contact angle, diode methane contact angle, surface free energy, disperse degree, and polarity degree.

[0395] The surface tension, the water contact angle, the diode methane contact angle, the surface free energy, the disperse degree, and the polarity degree can be measured on the surface of the polyester sheet.

[0396] In the biodegradable polyester resin composition according to the examples, the surface tension may be about 30 dyne to about 55 dyne. In the biodegradable polyester resin composition according to the examples, the surface tension may be about 35 dyne to about 50 dyne.

[0397] In the biodegradable polyester resin composition according to the examples, the water contact angle may be about 60° to about 90°. In the biodegradable polyester resin composition according to the examples, the water contact angle may be about 65° to about 85°. In the biodegradable polyester resin composition according to the examples, the water contact angle may be about 67° to about 80°.

[0398] In the biodegradable polyester resin composition according to the examples, the diode methane contact angle may be from about 20° to about 40°. In the biodegradable polyester resin composition according to the examples, the diode methane contact angle may be from about 20° to about 35°.

[0399] In the biodegradable polyester resin composition according to the examples, the surface free energy may be from about 40 mN / m to about 60 mN / m. In the biodegradable polyester resin composition according to the examples, the surface free energy may be from about 42 mN / m to about 55 mN / m.

[0400] In the biodegradable polyester resin composition according to the examples, the dispersity may be from about 35 mN / m to about 55 mN / m. In the biodegradable polyester resin composition according to the examples, the dispersity may be from about 40 mN / m to about 50 mN / m.

[0401] In the biodegradable polyester resin composition according to the examples, the polarity may be from about 2 mN / m to about 8 mN / m. In the biodegradable polyester resin composition according to the examples, the polarity may be from about 3 mN / m to about 7 mN / m.

[0402] The biodegradable polyester resin composition according to the examples may have the surface tension, the water contact angle, the diode methane contact angle, the surface free energy, the dispersity, and the polarity within the above ranges by virtue of the composition such as the biodegradable polyester resin, the oligomer, the reinforcing material, the chain extender, the metal salt, the hydrolysis resistant agent, and the heat stabilizer, and processes such as the esterification reaction, the polycondensation reaction, the chain extension reaction, and the heat treatment reaction. As a result, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis and an appropriate degree of biodegradation.

[0403] The above content will be described in more detail with the following examples. However, the following examples are for illustrative purposes of the present invention, and the scope of the examples is not limited thereto.

[0404] <Production Example> Production of Pretreated Cellulose Nanocrystals Dry powder cellulose nanocrystals (NVC-100, manufacturer: Celluforce) having a particle size of about 1 μm to about 50 μm were dispersed in water at 1% by weight, and then ultrasonic treatment was performed for 1 minute at an output of 20,000 J / s using a tip-type ultrasonic disperser to produce pretreated nanocellulose.

[0405] Monomer Composition for Oligomer Production 1,4-Butanediol (1,4-BDO), terephthalic acid (TPA), and adipic acid (AA) were uniformly mixed at a molar ratio of about 3:1:2. At this time, the average particle size of the terephthalic acid (TPA) was about 150 μm.

[0406] Production of Oligomer 1,4-Butanediol (1,4-BDO), terephthalic acid (TPA), and adipic acid (AA) were uniformly mixed at a molar ratio of about 3:1:2. At this time, the average particle size of the terephthalic acid (TPA) was about 130 μm. Then, the mixture was subjected to an esterification reaction at a temperature of about 220 °C and normal pressure for about 10 minutes to produce the hydrolysis regulator.

[0407] Chain Extender: Tris(4-isocyanatophenyl)methane

[0408] <Example> Example 1 Production of Biodegradable Polyester Resin First Step: Step of Obtaining a Slurry by Pretreatment As shown in Table 1, the pre-treated nanocellulose, 1,4-butanediol (1,4-BDO) and terephthalic acid (TPA) were mixed at a molar ratio of 1.2:1 (1,4-BDO:TPA) and charged into a slurry tank (the bottom of the slurry tank is of the anchor type, the height to the agitator is 40 mm, and it is equipped with three rotating blades) in a catalyst-free state. At this time, the D50 of the terephthalic acid (TPA) was 130 μm, and the standard deviation (SD) with respect to the D50 of the terephthalic acid (TPA) was 30.

[0409] Next, the mixture was stirred at 60 °C and 100 rpm for 1 hour for pretreatment to obtain a slurry without phase separation.

[0410] Second stage: The stage of obtaining a prepolymer The slurry obtained in the first stage was charged into a reactor through a supply line. After adding 250 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), a titanium-based catalyst, a primary esterification reaction was carried out at 220 °C and normal pressure for about 1 hour and 30 minutes until 95% of the by-product water was discharged.

[0411] To the reaction product, 53 mol% of 1,4-butanediol (1,4-BDO) based on the total molar number of the diol component, 53 mol% of adipic acid (AA) based on the total molar number of the dicarboxylic acid component, and 200 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), a titanium-based catalyst, were added based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Then, a secondary esterification reaction was carried out at 210 °C and normal pressure for about 2 hours and 30 minutes until 95% of the by-product water was discharged to produce a secondary esterification reaction product.

[0412] Thereafter, the monomer composition was charged into the secondary esterification reaction product at a content of about 1 part by weight based on 100 parts by weight of the esterification reaction product. The mixture of the monomer composition and the secondary esterification reaction product was subjected to a tertiary esterification reaction at a temperature of about 220°C for about 20 minutes. Thereafter, a prepolymer having a number average molecular weight of about 1200 g / mol was produced by the tertiary esterification reaction.

[0413] Step 3: Step of performing polycondensation reaction The prepolymer was charged with the prepolymer, tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), a titanium-based catalyst of 400 ppm, and 200 ppm of triethylene phosphate stabilizer, and stabilized for about 10 minutes. Thereafter, the reaction mixture was heated to 250°C and then subjected to a polycondensation reaction at 0.5 torr for 4 hours to produce a polymer having a weight average molecular weight of 55000 g / mol.

[0414] Thereafter, based on the polymer, about 0.5 wt% of tri(4-isocyanatophenyl)methane was added to the polymer. Thereafter, the polymer was subjected to a chain extension reaction at a temperature of about 240°C for about 10 minutes. Thereafter, it was cooled to 5°C and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0415] Example 2 As shown in Tables 1 and 2 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, monomer composition, and chain extender may vary. The polymer was cooled without performing a chain extension reaction to obtain biodegradable polyester resin pellets. Thereafter, the biodegradable polyester resin pellets were charged into a twin-screw extruder, melt-extruded at a temperature of about 250°C for about 2 minutes, cooled to about 5°C, and then cut to be produced into pellets again. Except for the contents and the steps, other steps were carried out substantially with reference to Example 1.

[0416] Examples 3 to 6 and Comparative Examples 1 to 2 As shown in Table 1 and Table 2 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, monomer composition, and chain extender are different. Except for the said contents and the said process, other processes were carried out substantially with reference to Example 1 or Example 2.

[0417] Examples 7 to 13 and Comparative Example 3 The primary esterification reaction and the secondary esterification reaction were carried out, and the tertiary esterification reaction was not carried out. Also, the stage of carrying out the polycondensation reaction was carried out by adding the said oligomer to the said prepolymer, and a polymer was produced. As shown in Table 3 and Table 4 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, oligomer, and chain extender are different, and the process conditions are different. Other processes were carried out substantially with reference to Example 1 or Example 2.

[0418] Production of biodegradable polyester sheet After preparing two Teflon (registered trademark) sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was positioned on one Teflon (registered trademark) sheet, and about 7 g of the produced polyester resin pellets were put into the stainless steel (SUS) frame (area 12 cm × 12 cm). Then, it was covered with the other Teflon (registered trademark) sheet and positioned at the center of a hot press (manufacturer: Wisrap, model: WL1600SA) having a surface size of about 25 cm × 25 cm. This was maintained at about 210 °C under a pressure of about 10 Mpa for about 3 minutes, then removed, and immediately cooled with water at about 20 °C for about 30 seconds, and a biodegradable polyester sheet having an area of about 10 cm × 10 cm and a thickness of about 300 μm was produced.

[0419] Production of biodegradable polyester film After drying the said biodegradable polyester resin pellets at 80 °C for 5 hours, they were melt-extruded at 160 °C using a blown film extrusion line (manufacturer: Ujin Engineering) to produce a biodegradable polyester film having a thickness of 50 μm.

[0420]

Table 1

[0421] As shown in Table 2 below, the molar ratio of the monomer composition and the conditions of the tertiary esterification reaction are different.

[0422]

Table 2

[0423]

Table 3

[0424]

Table 4

[0425] <Evaluation Example> Evaluation Example 1: Average particle size (D50) and standard deviation <Average particle size (D50) and standard deviation of aromatic dicarboxylic acid> Using a particle size analyzer Microtrac S3500 (Microtrac Inc) in the particle size distribution (PSD), the average particle size (D50) and standard deviation (SD, Standard Deviation) of the aromatic dicarboxylic acid (TPA or DMT) were determined under the following conditions:

[0426] Operating environment - Temperature: 10~35 °C, Humidity: 90%RH, non-condensing maximum - D50 and SD, which are the average particle size distributions by interval, were measured.

[0427] The standard deviation means the square root of the variance and can be calculated using software.

[0428] <Particle size of nanocellulose> Regarding nanocellulose, the particle size and particle size deviation were measured by the principle of dynamic light scattering (DLS) at a temperature of 25 °C and a measurement angle of 175 ° using a Zetasizer Nano ZS (manufactured by Malvern). At this time, the value of the peak derived from the polydispersity index (PdI) in the confidence interval of 0.5 was measured as the particle diameter.

[0429] Evaluation Example 2: Degree of hydrolysis After immersing the biodegradable polyester resins produced in the examples and comparative examples in water at 80 °C (100% RH), a hydrolysis acceleration test was conducted.

[0430] Specifically, 5 g of the polyester resins of the examples and comparative examples were placed in 500 mL of deionized water (DI Water), and then blocked with a stopper so that the water would not evaporate. A hydrolysis acceleration test was conducted in a convection (hot air) oven at 80 °C. The humidity environment of the biodegradable polyester sheet is the same as that when immersed in water, i.e., at 100% RH.

[0431] Using gel permeation chromatography (GPC), the number average molecular weight of the polyester resins of the examples and comparative examples after a certain period of time was measured. The value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period of time by the initial number average molecular weight was derived as the degree of hydrolysis.

[0432] Evaluation Example 3: Degree of biodegradation The biodegradable polyester resins produced in the examples and comparative examples were mixed with the following compost, and a biodegradation acceleration test was conducted at a temperature of 60 °C and a humidity of 90%.

[0433] Using gel permeation chromatography (GPC), the number average molecular weight of the polyester resins of the examples and comparative examples after a certain period of time was measured. The value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period of time by the initial number average molecular weight was derived as the degree of biodegradation.

[0434] Compost Manufacturer: Taeheung F&G Product Name: Earth-Born Soil (By-Product Fertilizer Grade 1 Compost) Compost Constituents: 40 wt% pig manure, 15 wt% chicken manure, 37 wt% large sawdust, 5 wt% zeolite, 3 wt% microbial agent

[0435] Evaluation Example 4: Oligomer Content The biodegradable polyester pellets produced in the examples and comparative examples were pulverized to obtain biodegradable polyester powder having an average particle size (D50) of about 50 μm. The biodegradable polyester powder was immersed in acetonitrile for about 24 hours. Thereafter, the supernatant was sampled, and the molecular weight and content of the extracted components were measured by LC-MS using dibutyl phthalate as a standard.

[0436] HR-LC-MS Equipment: Model (Orbitrap HR LC-MS, Q-Exactive, Thermo Fisher) Column: C18 LC detector: 254 nm Eluent: 5% ACN (with 0.1% Formic acid) / 95% H 2 O-->100% ACN (with 0.1% Formic acid) Ionization mode: ESI mode Mass: Positive 50-750, 500-3000

[0437] Evaluation Example 5: Water Contact Angle and Polarity On the surface of the biodegradable polyester sheets produced in the examples and comparative examples, the water contact angle and polarity are measured under the following conditions.

[0438] Surface tension: Wetting tension test mixture No. 40-64 Manufacturer: Wako Components: Ethylene glycol, monoethyl ether Surface energy measuring instrument: MSA One-Click SFE (Product Name) / KRUSS (Manufacturer)

[0439] As described in Table 5 and Table 6 below, the biodegradability has been measured.

[0440]

Table 5

[0441]

Table 6

[0442] As described in Table 7 and Table 8 below, the degree of hydrolysis has been measured.

[0443]

Table 7

[0444]

Table 8

[0445] As in Table 9 and Table 10 below, the contents of the first oligomer, the second oligomer, the third oligomer, and the fourth oligomer have been measured.

[0446]

Table 9

[0447]

Table 10

[0448] Molecular weight of the first oligomer: 421.18 Molecular weight of the second oligomer: 623.3 Molecular weight of the third oligomer: 643.3 Molecular weight of the fourth oligomer: 843.4

[0449] As described in Tables 11 and 12 below, the surface physical properties of the biodegradable polyester sheets according to the examples and comparative examples were measured.

[0450]

Table 11

[0451]

Table 12

[0452] As described in Tables 5 to 12 above, the biodegradable resin composition according to the examples may have an appropriate degree of hydrolysis, an appropriate degree of biodegradability, and appropriate surface characteristics.

Industrial Applicability

[0453] The examples can be applied to biodegradable resin compositions, films, and molded articles.

Claims

1. A polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a hydrophilicity regulator having a molecular weight of 400 to 1300 and contained at 5000 ppm to 20000 ppm, a biodegradable polyester resin composition.

2. The biodegradable polyester resin composition according to claim 1, wherein the hydrophilicity regulator contains an oligomer formed by reactions of at least two or more of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid.

3. The biodegradable polyester resin composition according to claim 1, wherein the degree of hydrolysis after 1 week is 35% to 60%, the degree of hydrolysis after 3 weeks is 85% or more, and the degree of hydrolysis after 1 week and the degree of hydrolysis after 3 weeks are measured by the following measurement method. 【Measurement Method】 The degree of hydrolysis after 1 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 film is placed for 1 week under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%. The degree of hydrolysis after 3 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 film is placed for 3 weeks under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100%.

4. The biodegradable polyester resin composition according to claim 1, wherein the hydrophilicity regulator contains a first oligomer having a molecular weight between 415 and 425, a second oligomer having a molecular weight between 620 and 630, a third oligomer having a molecular weight between 640 and 650, and a fourth oligomer having a molecular weight between 840 and 850.

5. The biodegradable resin composition according to claim 4, wherein the content of the first oligomer is 3000 to 5000 ppm based on the polyester resin, the content of the second oligomer is 2000 ppm to 4000 ppm based on the polyester resin, the content of the third oligomer is 500 ppm to 2000 ppm based on the polyester resin, and the content of the fourth oligomer is 700 ppm to 2500 ppm based on the polyester resin.

6. The biodegradable polyester resin composition according to claim 1, wherein the hydrophilicity regulator contains a first oligomer, and the first oligomer contains one first unit represented by the following Chemical Formula 8 and one second unit represented by the following Chemical Formula 9.

7. ​ ​ ​ ​ ​ 【Chemical Formula 8】 【Chemical Formula 9】 ​ The hydrophilicity regulator contains a second oligomer and a third oligomer, the second oligomer contains one of the first units and two of the second units, the third oligomer contains two of the first units and one of the second units, the second oligomer is contained in the hydrophilicity regulator at a higher content than the third oligomer, The biodegradable polyester resin composition according to claim 6.

8. The hydrophilicity regulator further contains a fourth oligomer, the fourth oligomer contains two of the first units and two of the second units, The biodegradable polyester resin composition according to claim 7.

9. The water contact angle measured by the following measurement method is 65° to 90°, and the polarity measured by the following measurement method is 4 mN / m to 7 mN / m, The biodegradable polyester resin composition according to claim 1. [Measurement method] The biodegradable polyester resin composition is dried at a temperature of 80°C, placed in a stainless steel frame, compressed at a temperature of 210°C and a pressure of 10 MPa for 3 minutes to produce a polyester sheet having a thickness of 300 μm, and the water contact angle and the polarity are measured on the surface of the polyester sheet.

10. The biodegradation degree after 1 week is 45% to 65%, the biodegradation degree after 9 weeks is 85% or more, the biodegradation degree after 1 week and the biodegradation degree after 9 weeks are measured by the following measurement method, The biodegradable polyester resin composition according to claim 1. [Measurement method] The biodegradation degree after 1 week is the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed under composting conditions, a temperature of 60°C and a humidity of 90% for 1 week, the biodegradation degree after 9 weeks is the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed under composting conditions, a temperature of 60°C and a humidity of 90% for 9 weeks.

11. including a polyester resin containing a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, the hydrolysis degree after 1 week is 35% to 60%, the hydrolysis degree after 3 weeks is 85% or more, the hydrolysis degree after 1 week and the hydrolysis degree after 3 weeks are measured by the following measurement method, A biodegradable polyester resin composition. [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 with respect to the initial value when the biodegradable polyester resin composition is placed for one week under high temperature and high humidity conditions of a temperature of 80 ° C and a humidity of 100%. The degree of hydrolysis after three weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for three weeks under high temperature and high humidity conditions of a temperature of 80 ° C and a humidity of 100%.

12. The biodegradability after nine weeks is 85% or more, The biodegradability after nine weeks is the reduction rate of the molecular weight of the polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for nine weeks under composting conditions, a temperature of 60 ° C and a humidity of 90%. The biodegradable polyester resin composition according to claim 11.

13. The biodegradability after one week is 45% to 75%, The degree of biodegradation after one week is the reduction rate of the molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for one week under composting conditions, a temperature of 60 ° C and a humidity of 90%. The biodegradable polyester resin composition according to claim 11.

14. The degree of hydrolysis after two weeks is 80% to 95%, The degree of hydrolysis after two weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for two weeks under high temperature and high humidity conditions of a temperature of 80 ° C and a humidity of 100%. The biodegradable polyester resin composition according to claim 11.

15. The degree of hydrolysis after four weeks is 85% or more, The degree of hydrolysis after four weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for four weeks under high temperature and high humidity conditions of a temperature of 80 ° C and a humidity of 100%. The increase rate of the degree of hydrolysis from one week to two weeks is 29% / week to 50% / week, and the increase rate of the degree of hydrolysis from three weeks to four weeks is 0.01% / week to 3% / week. The biodegradable polyester resin composition according to claim 14.

16. The biodegradability after four weeks is 73% to 85%, The biodegradability after 4 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 4 weeks under high temperature and high humidity conditions of 80°C and 100% humidity. The increase rate of biodegradability from 1 week to 4 weeks is 3.5% / week to 8% / week. The biodegradable polyester resin composition according to claim 13.

17. The acid value is 2.0 mgKOH / g or less. The biodegradable polyester resin composition according to claim 11.

18. Containing an oligomer with a molecular weight of 400 to 1300 at 5000 ppm to 20000 ppm based on the total composition. The biodegradable polyester resin composition according to claim 17.

19. The oligomer contains the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. The biodegradable polyester resin composition according to claim 18.

20. A polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a hydrophilic regulator with a molecular weight of 400 to 1300 at 5000 ppm to 20000 ppm. A biodegradable molded article containing a biodegradable resin composition.

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