Biodegradable molded article, biodegradable polyester resin composition, and biodegradable polyester film

Abstract

The example includes a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and provides a biodegradable molded article with a wet hardness reduction rate of 12% to 25%. The biodegradable molded article is processed into a polyester block having a thickness of 2.5 mm, and the initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at 30 ° C for 1 hour are measured. The wet hardness reduction rate is a value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

Description

Technical Field

[0001] The examples relate to biodegradable molded articles, biodegradable polyester resin compositions, and biodegradable polyester films containing the same.

Background Art

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

[0003] To overcome these limitations of polymers, active research has been conducted on biodegradable polymers that can be decomposed within a short period of 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 seek to provide biodegradable molded articles, biodegradable polyester resin compositions, and biodegradable polyester films containing the same, which have improved marine biodegradability and appropriate hydrolysis resistance.

Means for Solving the Problems

[0006] The biodegradable molded article according to the embodiment contains a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and has a wet hardness reduction rate of 12% to 25%. The wet hardness reduction rate is measured by the following measurement method.

[0007] [Measurement method] The biodegradable molded article is processed into a polyester block having a thickness of 2.5 mm, and the initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at 30 °C for 1 hour are measured. The wet hardness reduction rate is a value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

[0008] The biodegradable molded article according to an embodiment may further contain a metal salt.

[0009] The biodegradable molded article according to an embodiment may further contain an ester polyol.

[0010] The biodegradable polyester resin composition according to an embodiment contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and has a wet hardness reduction rate of 12% to 25%. The wet hardness reduction rate is measured by the following measurement method.

[0011] [Measurement method] The biodegradable polyester resin composition is molded into a polyester block having a thickness of 2.5 mm, and the initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at 30 °C for 1 hour are measured. The wet hardness reduction rate is a value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

[0012] In one embodiment, the initial hardness may be 30 to 45 in Shore D hardness, and the wet hardness may be 25 to 40 in Shore D hardness.

[0013] In one embodiment, the rate of decrease in wet hardness may be 13% to 22%.

[0014] In the biodegradable polyester resin composition according to one embodiment, the nitrogen content may be 0.1 ppm to 500 ppm.

[0015] In one embodiment, the water contact angle on the surface of the polyester block may be 65° to 90°.

[0016] In one embodiment, the polarity on the surface of the polyester block may be 4 mN / m to 7 mN / m.

[0017] In one embodiment, in the polyester resin, the ratio of the diol that binds between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid among the diols may be 0.3 to 0.7.

[0018] In one embodiment, the ratio of the diol that binds between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid among the diols may be 0.2 to 0.3.

[0019] 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 may be measured by the following measurement method.

[0020] [Measurement method] The degree of hydrolysis after 1 week is the rate of decrease in molecular weight relative to the initial value when the biodegradable polyester resin is placed for 1 week under the 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 rate of decrease in molecular weight relative to the initial value when the biodegradable polyester resin is placed for 3 weeks under the high-temperature and high-humidity conditions of a temperature of 80°C and a humidity of 100%.

[0021] In one embodiment, the difference between the wet hardness after immersion in water at 30°C for 1 hour and the wet hardness after immersion in water at 30°C for 20 hours may be 10% or less based on the initial hardness.

[0022] In one embodiment, the difference between the wet hardness after immersion in water at 30°C for 1 hour and the wet hardness after immersion in water at 70°C for 1 hour may be 10% or less based on the initial hardness.

[0023] The biodegradable polyester resin composition according to another embodiment contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and the first weight swelling ratio is 15% or less, and the first weight swelling ratio may be measured by the following measurement method.

[0024] [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. The initial weight of the polyester sheet and the weight of the polyester sheet after immersion in acetone at room temperature for 24 hours are measured, and the first weight swelling ratio is the value obtained by dividing the difference between the weight after immersion and the initial weight by the initial weight.

[0025] In the biodegradable polyester resin composition according to one embodiment, the first volume swelling ratio is 25% or less, and the first volume swelling ratio may be measured by the following measurement method.

[0026] [Measurement method] The initial volume of the polyester sheet and the volume of the polyester sheet after immersion in acetone at room temperature for 24 hours are measured, and the first volume swelling ratio is the value obtained by dividing the difference between the volume after immersion and the initial volume by the initial volume.

[0027] In a biodegradable polyester resin composition according to an embodiment, the second weight swelling ratio may be 20% or less, and the second weight swelling ratio may be measured by the following measurement method.

[0028] [Measurement method] The initial weight of the polyester sheet and the weight after the polyester sheet is immersed in acetonitrile at room temperature for 24 hours are measured, and the second weight swelling ratio is the value obtained by dividing the difference between the weight after immersion and the initial weight by the initial weight.

[0029] In a biodegradable polyester resin composition according to an embodiment, the second volume swelling ratio may be 25% or less, and the second volume swelling ratio may be measured by the following measurement method.

[0030] [Measurement method] The initial volume of the polyester sheet and the volume after the polyester sheet is immersed in acetonitrile at room temperature for 24 hours are measured, and the second volume swelling ratio is the value obtained by dividing the difference between the volume after immersion and the initial volume by the initial volume.

[0031] A biodegradable polyester resin composition according to an embodiment may further contain polycaprolactone diol.

[0032] In a biodegradable polyester resin composition according to an embodiment, the weight swelling ratio may be less than 12%. [Advantages of the Invention]

[0033] The biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the embodiment have an appropriate wet hardness reduction rate. As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the embodiment may contain appropriate moisture when discarded in a high-humidity environment or in water such as the sea. As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the embodiment can be easily decomposed in a high-humidity environment, particularly in water.

[0034] In addition, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples may have an appropriate wet hardness reduction rate and an appropriate initial hydrolysis resistance. As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples can be easily biodegradable when discarded after use by the user while maintaining appropriate mechanical and chemical properties during the user's usage period.

[0035] The biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples can be easily biodegradable in a high-humidity soil environment because they have an appropriate wet hardness reduction rate. Moreover, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples can be easily biodegradable even in water. In particular, when the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples are discarded in water such as the ocean, moisture and inorganic ions can easily penetrate into the biodegradable polyester resin composition according to the examples. As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples can be easily biodegradable even in water such as the sea, lake, and river.

[0036] In addition, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable polyester film according to the examples have appropriately low weight swelling rates and volume swelling rates with respect to organic solvents. The biodegradable molded article, biodegradable polyester resin composition, and biodegradable polyester film according to the examples may have a low swelling rate with respect to organic solvents such as acetone and acetonitrile.

[0037] As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable polyester film according to the examples may have high solvent resistance. Therefore, even when exposed to an organic solvent or the like, improved mechanical properties can be maintained.

[0038] In addition, the biodegradable molded article, the biodegradable polyester resin composition, and the biodegradable polyester film according to the examples may have an appropriately low swelling ratio and an appropriate initial hydrolysis resistance. As a result, the biodegradable molded article, the biodegradable polyester resin composition, and the biodegradable polyester film according to the examples can be easily biodegradable when discarded after use by the user while maintaining appropriate mechanical and chemical properties during the user's usage period.

[0039] In addition, the biodegradable molded article, the biodegradable polyester resin composition, and the biodegradable polyester film according to the examples may have a high degree of biodegradability. As a result, the biodegradable molded article, the biodegradable polyester resin composition, and the biodegradable polyester film according to the examples have high solvent resistance and high hydrolysis resistance in the real-life area and can be easily biodegradable when discarded.

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 as long as the gist of the invention remains unchanged.

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

[0043] In addition, it should be understood that any numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification are all modified by the term "about" unless otherwise specified.

[0044] Terms such as first, second, primary, secondary, etc. in this specification are used to describe various components, and the above components are not limited by the above terms. The above 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 a diol. In the biodegradable polyester resin, the dicarboxylic acid residue may be represented by a dicarboxylic acid. Also, the residue may be represented by the component.

[0048] The diol may be an aliphatic diol. The diol may be a bio-derived diol. The diol may be at least one selected from 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 at least one selected from 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 at least one selected from 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 including the diol to the total dicarboxylic acid residues including the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid may be about 1:0.9 to about 1:1.1. The molar ratio of the total diol residues to the total dicarboxylic acid residues may be about 1:0.95 to about 1:1.05.

[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] In addition, 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 binding to the aliphatic dicarboxylic acid.

[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 binding to the aromatic dicarboxylic acid.

[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. 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 0.80 to 1.1. Also, 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 crosslinking ratio described later. That is, the number of the first blocks may increase as the molar ratio of the aromatic dicarboxylic acid increases, as the molecular weight of the biodegradable polyester resin increases, and as the crosslinking ratio described later increases.

[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 rate of alternation described later. That is, the number of the first blocks may increase due to an increase in the molar ratio of the aliphatic dicarboxylic acid, an increase in the molecular weight of the biodegradable polyester resin, and an increase in the rate of alternation described later.

[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 a butylene group.

[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 containing 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 containing 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 containing 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 containing 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 containing a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof, and a second block containing a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

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

[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 Chemical formula 6 below.

[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 further 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 characteristics.

[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 characteristics.

[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 contain the following bonding structures 1 to 3.

[0104] [Bonding structure 1] -Aromatic dicarboxylic acid - Diol - Aliphatic dicarboxylic acid - [Bonding structure 2] -Aromatic dicarboxylic acid - Diol - Aromatic dicarboxylic acid - [Bonding structure 3] -Aliphatic dicarboxylic acid - Diol - Aliphatic dicarboxylic acid -

[0105] The diol contained in the above bonding structure 1 binds to the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. The diol contained in the above bonding structure 1 may be directly esterified to the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0106] Also, the diol contained in the above bonding structure 2 binds to the aromatic dicarboxylic acid and the aromatic dicarboxylic acid between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid. The diol contained in the above bonding structure 2 may be directly esterified to the aromatic dicarboxylic acid and the aromatic dicarboxylic acid between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid.

[0107] Also, the diol contained in the above bonding structure 3 bonds to the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid between the aliphatic dicarboxylic acids. The diol contained in the above bonding structure 3 may be directly esterified between the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid to the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0108] In the biodegradable polyester resin, the above bonding structure 1 may be represented by the following Chemical Formula 7.

[0109]

Chemical Formula

[0110] 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 R3 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0111] In the biodegradable polyester resin, the above bonding structure 2 may be represented by the following Chemical Formula 8.

[0112]

Chemical Formula

[0113] Similarly, R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0114] In the biodegradable polyester resin, the above bonding structure 3 may be represented by the following Chemical Formula 9.

[0115]

Chemical Formula

[0116] R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and R3 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0117] Further, the above bonding structure 1 may be represented by Chemical Formula 10 below.

[0118]

Chemical Formula

[0119] Further, the above bonding structure 2 may be represented by Chemical Formula 11 below.

[0120]

Chemical Formula

[0121] Further, the above bonding structure 3 may be represented by Chemical Formula 12 below.

[0122]

Chemical Formula

[0123] The biodegradable polyester resin has an alternating ratio.

[0124] The alternating ratio is the ratio of the diol that binds between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid among the diols. That is, the alternating ratio may be the ratio of the diol contained in the above bonding structure 1 among the diols. The alternating ratio may be a value obtained by dividing the number of moles of the diol contained in the above bonding structure 1 by the sum of the number of moles of the diol contained in the above bonding structure 1, the number of moles of the diol contained in the above bonding structure 2, and the number of moles of the diol contained in the above bonding structure 3.

[0125] That is, the crosslinking ratio may be the ratio of the diols in which two of the total diols are bonded between the dicarboxylic acids.

[0126] The crosslinking ratio can be calculated by the following formula (1).

[0127] [Formula (1)] JPEG2025522290000014.jpg20128

[0128] Here, DM1 is the molar ratio of the diols contained in the above bonding structure 1, DM2 is the molar ratio of the diols contained in the above bonding structure 2, and DM3 is the molar ratio of the diols contained in the above bonding structure 3.

[0129] In the biodegradable polyester resin, the crosslinking ratio may be about 0.3 to about 0.7. In the biodegradable polyester resin, the crosslinking ratio may be about 0.37 to about 0.59. In the biodegradable polyester resin, the crosslinking ratio may be about 0.4 to about 0.56. In the biodegradable polyester resin, the crosslinking ratio may be about 0.45 to about 0.53.

[0130] Also, the biodegradable polyester resin contains a proportion of hard segments.

[0131] The proportion of the hard segments is the proportion of the diols in which the aromatic dicarboxylic acid and the aromatic dicarboxylic acid are bonded between the diols.

[0132] The proportion of the hard segments may be the molar ratio of the diols contained in the above bonding structure 2 among the total diols. The proportion of the hard segments may be the value obtained by dividing the number of moles of the diols contained in the above bonding structure 2 by the sum of the number of moles of the diols contained in the above bonding structure 1, the number of moles of the diols contained in the above bonding structure 2, and the number of moles of the diols contained in the above bonding structure 3.

[0133] The ratio of the hard segment may be represented by the following Mathematical Formula 2.

[0134] [Mathematical Formula 2] JPEG2025522290000015.jpg20139

[0135] Here, the DM1 is the molar ratio of the diol contained in the bonding structure 1, the DM2 is the molar ratio of the diol contained in the bonding structure 2, and the DM3 is the molar ratio of the diol contained in the bonding structure 3.

[0136] The ratio of the hard segment may be about 0.15 to about 0.35. The ratio of the hard segment may be about 0.2 to about 0.3. The ratio of the hard segment may be about 0.21 to about 0.29. The ratio of the hard segment may be about 0.22 to about 0.28.

[0137] Further, the biodegradable polyester resin composition contains a soft segment.

[0138] The ratio of the soft segment is the ratio of the diol that binds between the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid among the diols.

[0139] The ratio of the soft segment may be the molar ratio of the diol contained in the bonding structure 3 among all the diols. The ratio of the soft segment may be a value obtained by dividing the number of moles of the diol contained in the bonding structure 3 by the sum of the number of moles of the diol contained in the bonding structure 1, the number of moles of the diol contained in the bonding structure 2, and the number of moles of the diol contained in the bonding structure 3.

[0140] The ratio of the soft segment may be represented by the following Mathematical Formula 3.

[0141] [Mathematical Formula 3] JPEG2025522290000016.jpg20139

[0142] Here, the DM1 is the molar ratio of the diol contained in the bonding structure 1, the DM2 is the molar ratio of the diol contained in the bonding structure 2, and the DM3 is the molar ratio of the diol contained in the bonding structure 3.

[0143] The proportion of the soft segment may be about 0.16 to about 0.36. The proportion of the soft segment may be about 0.21 to about 0.31. The proportion of the soft segment may be about 0.22 to about 0.30. The proportion of the hard segment may be about 0.23 to about 0.29.

[0144] The proportion of the soft segment may be even larger than the proportion of the hard segment.

[0145] The ratio of the hard segment to the soft segment may be about 0.92 to about 0.99. That is, the value obtained by dividing the DM2 by the DM3 may be about 0.92 to about 0.99.

[0146] The proportion of the crosslinking, the proportion of the hard segment, and the proportion of the soft segment can be measured by nuclear magnetic resonance spectroscopy. The biodegradable polyester resin composition according to the example is dissolved in a solvent such as CDCl3 and analyzed by a nuclear magnetic resonance (NMR) apparatus at room temperature 1 H-NMR and / or 13 C-NMR analysis.

[0147] When the diol is 1,4-butanediol, the aromatic dicarboxylic acid is terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid is adipic acid, the analysis of the biodegradable polyester resin by the nuclear magnetic resonance spectroscopy may include a first peak, a second peak, a third peak, a fourth peak, a fifth peak, a sixth peak, a seventh peak, an eighth peak, a ninth peak, a tenth peak, and an eleventh peak.

[0148] For example, when the diol is 1,4-butanediol, the aromatic dicarboxylic acid is terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid is adipic acid, the analysis of the biodegradable polyester resin by the nuclear magnetic resonance spectroscopy may include peaks derived from the diol of the above bonding structure 1, peaks derived from the diol of the above bonding structure 2, and peaks derived from the above bonding structure 3 at about 3.5 ppm to about 4.6 ppm.

[0149] In the range of about 3.5 ppm to about 4.6 ppm, the first peak, the second peak, the third peak, and the fourth peak may be defined in order from the higher ppm to the lower ppm. Also, in the range of about -3.4 ppm to about -4.3 ppm based on the ppm of the ninth peak, the first peak, the second peak, the third peak, and the fourth peak may be defined in order from the higher ppm to the lower ppm. Here, at this time, the first peak may be derived from the diol contained in the second bonding unit, the second peak and the third peak may be derived from the diol contained in the first bonding unit, and the fourth peak may be derived from the diol contained in the third bonding unit.

[0150] The direction of -ppm may be the upfield direction or the shielded direction. For example, -3.4 ppm may mean the position at 3.4 ppm in the upfield direction. For example, -3.4 ppm may mean the position at 3.4 ppm in the shielded direction.

[0151] Also, the analysis of the biodegradable polyester resin by the nuclear magnetic resonance spectroscopy may include peaks derived from the diol of the above bonding structure 1, peaks derived from the diol of the above bonding structure 2, and peaks derived from the above bonding structure 3 also at about 1.0 ppm to about 2.5 ppm.

[0152] The 10th peak, the 5th peak, the 6th peak, the 7th peak, the 8th peak, and the 11th peak may be defined in the range of about 1.0 ppm to about 2.5 ppm in descending order of ppm from high to low. The 5th peak, the 6th peak, the 7th peak, the 8th peak, and the 11th peak may be defined in the range of about -6.0 ppm to about -6.7 ppm with reference to the ppm of the 9th peak in descending order of ppm from high to low. At this time, the 5th peak may be derived from the diol contained in the second bonding unit, the 6th peak and the 7th peak may be derived from the diol contained in the first bonding unit, and the 8th peak may be derived from the diol contained in the third bonding unit.

[0153] Also, the 9th peak may be formed in the range of about 7.5 ppm to about 8.5 ppm. The 9th peak may be derived from the aromatic dicarboxylic acid. The 9th peak may be derived from the aromatic ring contained in the aromatic dicarboxylic acid. The 9th peak may be derived from the aromatic ring contained in the terephthalic acid or dimethyl terephthalate.

[0154] The 10th peak and the 11th peak may be derived from the aliphatic dicarboxylic acid. The 10th peak and the 11th peak may be derived from the adipic acid.

[0155] The first peak may be located at about -3.6 ppm to about -3.68 ppm based on the ppm of the ninth peak. The second peak may be located at about -3.69 ppm to about -3.75 ppm based on the ppm of the ninth peak. The third peak may be located at about -3.9 ppm to about -3.97 ppm based on the ppm of the ninth peak. The fourth peak may be located at about -3.98 ppm to about -4.1 ppm based on the ppm of the ninth peak. The fifth peak may be located at about -6.0 ppm to about -6.19 ppm based on the ppm of the ninth peak. The sixth peak may be located at about -6.2 ppm to about -6.26 ppm based on the ppm of the ninth peak. The seventh peak may be located at about -6.27 ppm to about -6.34 ppm based on the ppm of the ninth peak. The eighth peak may be located at about -6.35 ppm to about -6.42 ppm based on the ppm of the ninth peak. The tenth peak may be located at about -5.6 ppm to about -5.8 ppm based on the ppm of the ninth peak. The eleventh peak may be located at about -6.421 ppm to about -6.5 ppm based on the ppm of the ninth peak. The positions based on the ppm of the ninth peak may be the positions of each peak when the position of the ninth peak is 0 ppm.

[0156] Also, the areas of the first peak, the second peak, the third peak, the fourth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, the tenth peak, and the eleventh peak can be normalized based on the area of the ninth peak. That is, when the area of the ninth peak is 1, the areas of the first peak, the second peak, the third peak, the fourth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, the tenth peak, and the eleventh peak can be determined relatively.

[0157] The ratio of the interaction can be derived by the following Equation 4 or Equation 5.

[0158] [Equation 4] JPEG2025522290000017.jpg19128

[0159] Here, the PA1 is the area of the first peak, the PA2 is the area of the second peak, the PA3 is the area of the third peak, and the PA4 is the area of the fourth peak.

[0160] [Equation 5] JPEG2025522290000018.jpg19128

[0161] Here, the PA5 is the area of the fifth peak, the PA6 is the area of the sixth peak, the PA7 is the area of the seventh peak, and the PA8 is the area of the eighth peak.

[0162] The ratio of the hard segment can be derived by the following Equation 6 or the following Equation 7.

[0163] [Equation 6] JPEG2025522290000019.jpg20147

[0164] Here, the PA1 is the area of the first peak, the PA2 is the area of the second peak, the PA3 is the area of the third peak, and the PA4 is the area of the fourth peak.

[0165] [Equation 7] JPEG2025522290000020.jpg20147

[0166] Here, the PA5 is the area of the fifth peak, the PA6 is the area of the sixth peak, the PA7 is the area of the seventh peak, and the PA8 is the area of the eighth peak.

[0167] The ratio of the soft segment can be derived by the following formula (8) or formula (9).

[0168] [Formula 8] JPEG2025522290000021.jpg20147

[0169] Here, the PA1 is the area of the first peak, the PA2 is the area of the second peak, the PA3 is the area of the third peak, and the PA4 is the area of the fourth peak.

[0170] [Formula 9] JPEG2025522290000022.jpg20147

[0171] Here, the PA5 is the area of the fifth peak, the PA6 is the area of the sixth peak, the PA7 is the area of the seventh peak, and the PA8 is the area of the eighth peak.

[0172] The area of the first peak may be about 0.35 to about 0.6. The area of the first peak may be about 0.4 to about 0.55. The area of the first peak may be about 0.43 to about 0.5. The area of the first peak may be about 0.43 to about 0.52. The area of the first peak may be about 0.45 to about 0.49.

[0173] The area of the second peak may be about 0.37 to about 0.57. The area of the second peak may be about 0.41 to about 0.54. The area of the second peak may be about 0.45 to about 0.53. The area of the second peak may be about 0.45 to about 0.55. The area of the second peak may be about 0.47 to about 0.53.

[0174] The area of the third peak may be from about 0.37 to about 0.57. The area of the third peak may be from about 0.41 to about 0.54. The area of the third peak may be from about 0.45 to about 0.53. The area of the third peak may be from about 0.45 to about 0.55. The area of the third peak may be from about 0.47 to about 0.53.

[0175] The area of the fourth peak may be from about 0.4 to 0.7. The area of the fourth peak may be from about 0.45 to about 0.65. The area of the fourth peak may be from about 0.48 to about 0.6. The area of the fourth peak may be from about 0.48 to 0.60. The area of the fourth peak may be from about 0.50 to about 0.58.

[0176] The area of the fifth peak may be from about 0.35 to about 0.6. The area of the fifth peak may be from about 0.4 to about 0.55. The area of the fifth peak may be from 0.43 to about 0.53. The area of the fifth peak may be from about 0.43 to about 0.52. The area of the fifth peak may be from about 0.45 to about 0.49.

[0177] The area of the sixth peak may be from about 0.35 to about 0.6. The area of the sixth peak may be from about 0.4 to about 0.55. The area of the sixth peak may be from 0.43 to about 0.5. The area of the sixth peak may be from about 0.45 to about 0.55. The area of the sixth peak may be from about 0.47 to about 0.53.

[0178] The area of the seventh peak may be from about 0.41 to about 0.71. The area of the seventh peak may be from about 0.45 to about 0.65. The area of the seventh peak may be from about 0.48 to about 0.6. The area of the seventh peak may be from about 0.45 to about 0.55. The area of the seventh peak may be from about 0.47 to about 0.53.

[0179] The area of the eighth peak may be from about 0.4 to about 0.7. The area of the eighth peak may be from about 0.45 to about 0.65. The area of the eighth peak may be from about 0.48 to about 0.6. The area of the eighth peak may be from about 0.48 to 0.60. The area of the eighth peak may be from about 0.50 to about 0.58.

[0180] The area of the tenth peak may be from about 0.7 to about 2.5. The area of the tenth peak may be from 0.75 to about 2. The area of the tenth peak may be from 0.8 to about 1.5. The area of the tenth peak may be from about 1.0 to about 1.15. The area of the tenth peak may be from about 1.02 to about 1.13.

[0181] The area of the eleventh peak may be from about 0.7 to about 3.5. The area of the eleventh peak may be from about 0.7 to about 3. The area of the eleventh peak may be from 0.8 to about 2.5. The area of the eleventh peak may be from about 1.0 to about 1.15. The area of the eleventh peak may be from about 1.02 to about 1.13.

[0182] Also, the sum of the area of the first peak, the area of the second peak, the area of the third peak, and the area of the fourth peak may be from about 1.49 to about 2.44. The sum of the area of the first peak, the area of the second peak, the area of the third peak, and the area of the fourth peak may be from about 1.81 to about 2.16. The sum of the area of the first peak, the area of the second peak, the area of the third peak, and the area of the fourth peak may be from about 1.9 to about 2.2. The sum of the area of the first peak, the area of the second peak, the area of the third peak, and the area of the fourth peak may be from about 1.95 to about 2.1. Here, the sum of the area of the first peak, the area of the second peak, the area of the third peak, and the area of the fourth peak may mean the sum of the number of total ester bonds based on the number of terephthalic acid.

[0183] The sum of the area of the second peak and the area of the third peak may be from about 0.95 to about 1.10. The sum of the area of the second peak and the area of the third peak may be from about 0.98 to about 1.07. Here, the sum of the area of the first peak and the area of the third peak may mean the degree to which the molecular bonds of the biodegradable polyester resin extend.

[0184] The ratio of the area of the fourth peak to the area of the first peak (area of the fourth peak / area of the first peak) may be from about 1.1 to about 1.3. The ratio of the area of the fourth peak to the area of the first peak may be from about 0.67 to about 2.00. The ratio of the area of the fourth peak to the area of the first peak may be from about 0.96 to about 1.40. The ratio of the area of the fourth peak to the area of the first peak may be from about 1.15 to about 1.25. The ratio of the area of the fourth peak to the area of the first peak may mean the ratio of the soft segment to the hard segment in the molecular structure of the biodegradable polyester resin. That is, the higher the ratio of the area of the fourth peak to the area of the first peak, the more flexible the biodegradable polyester resin may be.

[0185] The ratio of the area of the fourth peak to the area of the third peak (area of the fourth peak / area of the third peak) may be from about 0.7 to about 1.89. The ratio of the area of the fourth peak to the area of the third peak may be from about 0.91 to about 1.33. The ratio of the area of the fourth peak to the area of the third peak may be from about 1.0 to about 1.2. The ratio of the area of the fourth peak to the area of the third peak may be from about 1.01 to about 1.1.

[0186] The ratio of the area of the first peak to the area of the second peak (area of the first peak / area of the second peak) may be from about 0.61 to about 1.62. The ratio of the area of the first peak to the area of the second peak may be from about 0.81 to about 1.11. The ratio of the area of the first peak to the area of the second peak may be from about 0.85 to about 0.95. The ratio of the area of the first peak to the area of the second peak may be from about 0.86 to about 0.94.

[0187] Also, the ratio of the area of the fifth peak to the area of the first peak (area of the fifth peak / area of the first peak) may be from about 0.61 to about 1.71. The ratio of the area of the fifth peak to the area of the first peak may be from about 0.96 to about 1.40. The ratio of the area of the fifth peak to the area of the first peak may be from about 0.8 to about 1.2. The ratio of the area of the fifth peak to the area of the first peak may be from about 0.9 to about 1.1.

[0188] Also, the ratio of the area of the sixth peak to the area of the second peak (area of the sixth peak / area of the second peak) may be from about 0.58 to about 1.71. The ratio of the area of the sixth peak to the area of the first peak may be from about 0.86 to about 1.16. The ratio of the area of the sixth peak to the area of the first peak may be from about 0.8 to about 1.2. The ratio of the area of the sixth peak to the area of the first peak may be from about 0.9 to about 1.1.

[0189] Also, the ratio of the area of the seventh peak to the area of the third peak (area of the seventh peak / area of the third peak) may be from about 0.72 to about 1.92. The ratio of the area of the seventh peak to the area of the third peak may be from about 0.91 to about 1.33. The ratio of the area of the seventh peak to the area of the third peak may be from about 0.8 to about 1.2. The ratio of the area of the seventh peak to the area of the third peak may be from about 0.9 to about 1.1.

[0190] Also, the ratio of the area of the eighth peak to the area of the fourth peak (area of the eighth peak / area of the fourth peak) may be from about 0.59 to about 1.75. The ratio of the area of the eighth peak to the area of the fourth peak may be from about 0.80 to about 1.25. The ratio of the area of the eighth peak to the area of the fourth peak may be from about 0.8 to about 1.2. The ratio of the area of the eighth peak to the area of the fourth peak may be from about 0.9 to about 1.1.

[0191] Since the biodegradable polyester resin has the molecular structure as described above, the biodegradable polyester resin composition according to the examples may be more advantageous for providing a biodegradable polyester sheet, film or molded article that is excellent in biodegradability and hydrolysis resistance and has improved physical properties.

[0192] Also, since the biodegradable polyester resin has the molecular structure as described above, the biodegradable polyester resin composition according to the examples may have appropriate mechanical properties and appropriate UV resistance properties.

[0193] Since the biodegradable polyester resin has the molecular structure as described above, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0194] Since the biodegradable polyester resin has the molecular structure as described above, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance properties.

[0195] Since the first block and the second block have the characteristics as described above, the biodegradable polyester resin composition according to the examples may have an appropriate biodegradation rate.

[0196] Since the biodegradable polyester resin has the molecular structure as described above, the biodegradable polyester resin composition according to the examples may have an appropriate hydrolysis rate.

[0197] The biodegradable polyester resin may further contain a branching agent. The branching agent may include at least one selected from the group consisting of a polyhydric alcohol having three or more valences, an anhydride, or a polycarboxylic acid having three or more valences. 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.

[0198] At least one of the polyhydric alcohols having three or more valences may be selected from the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0199] At least one of the polycarboxylic acids having three or more valences may be 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.

[0200] The anhydride may contain at least one or more selected from the group consisting of trimellitic anhydride, succinic anhydride, methyl succinic anhydride, ethyl succinic anhydride, 2,3-butanedicarboxylic anhydride, 2,4-pentanedicarboxylic anhydride, 3,5-heptanedicarboxylic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, maleic anhydride, dodecyl succinic anhydride, or pyromellitic anhydride.

[0201] 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 total amount of the 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 total amount of the 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 total amount of the biodegradable polyester resin.

[0202] 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.

[0203] The biodegradable polyester resin may further contain an ester polyol. The ester polyol may be contained in the biodegradable polyester resin by being bonded in the molecular structure.

[0204] The ester polyol can be produced by a dehydration condensation reaction of a dibasic acid and a polyhydric alcohol. The dibasic acid may be at least one or more selected from the group consisting of adipic acid, isophthalic acid, or sebacic acid. The polyhydric alcohol may be at least one or more selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, 1,6-hexanediol, or 1,2-propanediol.

[0205] The weight average molecular weight of the ester polyol may be from about 500 to about 5000. The weight average molecular weight of the ester polyol may be from about 700 to about 4000. The weight average molecular weight of the ester polyol may be from about 800 to about 3500.

[0206] Also, the viscosity of the ester polyol may be from about 300 cps to about 20000 cps. The viscosity of the ester polyol may be from about 400 cps to about 15000 cps. The viscosity of the ester polyol may be from about 500 cps to about 14000 cps. The viscosity of the ester polyol may be the Brookfield viscosity at about 25 °C.

[0207] The OH value of the ester polyol may be from about 50 mgKOH / g to about 350 mgKOH / g. The OH value of the ester polyol may be from about 50 mgKOH / g to about 300 mgKOH / g.

[0208] The acid value of the ester polyol may be about 3 mgKOH / g or less. The acid value of the ester polyol may be about 2.5 mgKOH / g or less. The acid value of the ester polyol may be about 2 mgKOH / g or less.

[0209] The ester polyol may be contained in the biodegradable polyester resin in an amount of about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The ester polyol may be contained in the biodegradable polyester resin in an amount of about 0.5 part by weight to about 3 parts by weight based on 100 parts by weight of the biodegradable polyester resin. The ester polyol may be contained in the biodegradable polyester resin in an amount of about 1 part by weight to about 3 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0210] Since the ester polyol has the above characteristics, the biodegradable polyester resin composition according to the examples may have appropriate wet hardness, appropriate mechanical properties, appropriate solvent resistance, appropriate degree of hydrolysis, and appropriate degree of biodegradability.

[0211] The biodegradable polyester resin composition according to the examples 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 examples 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 examples 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 examples 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 examples 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 examples 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 examples 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 examples may be about 100 wt% based on the weight of the entire composition.

[0212] The biodegradable polyester resin composition according to the example may further contain a reinforcing material. The reinforcing material can improve the mechanical properties of the biodegradable polyester resin composition according to the example, 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 example due to ultraviolet rays. Further, the reinforcing material can adjust the hydrolysis characteristics of the biodegradable polyester resin composition according to the example. Further, the reinforcing material can adjust the biodegradability of the biodegradable polyester resin according to the example.

[0213] The reinforcing material may be a fiber derived from biomass. The reinforcing material may be a fiber made of an organic substance. The reinforcing material may be nanocellulose.

[0214] The nanocellulose may be one or more selected from the group consisting of nanocrystalline cellulose, cellulose nanofiber, 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.

[0215] The nanocellulose may contain a metal bonded ionically. The nanocrystalline cellulose may contain a sodium element. Further, the nanocrystalline cellulose may contain a sulphate. The nanocrystalline cellulose may contain a carboxylate. The nanocrystalline cellulose may be cellulose hydrogen sulphate sodium salt.

[0216] The nanocellulose may be represented by Chemical Formula 13 below.

[0217] [Chemical]

[0218] Here, x is from 1 to 35, and y may be from 1 to 10. x may be from 15 to 35, and y may be from 1 to 10.

[0219] The nanocellulose may have a specific surface area of about 200 m 2 / g to about 600 m 2 / g. The nanocellulose may have a specific surface area of about 300 m 2 / g to about 500 m 2 / g.

[0220] The weight-average molecular weight of the nanocellulose may be from about 10,000 g / mol to about 40,000 g / mol. The weight-average molecular weight of the nanocrystalline cellulose may be from about 11,000 g / mol to about 35,000 g / mol.

[0221] The moisture content of the nanocrystalline cellulose may be from about 2 wt% to about 8 wt%. The moisture content of the nanocrystalline cellulose may be from about 4 wt% to about 6 wt%.

[0222] The average diameter of the nanocellulose may be from about 0.5 nm to about 10 nm. The average diameter of the nanocellulose may be from about 1 nm to about 8 nm. The average diameter of the nanocellulose may be from about 1.5 nm to about 7 nm.

[0223] The average length of the nanocellulose may be from about 20 nm to about 200 nm. The average length of the nanocellulose may be from about 30 nm to about 180 nm. The average length of the nanocellulose may be from about 35 nm to about 150 nm.

[0224] By satisfying the diameter and length of the nanocellulose within 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.

[0225] The diameter and length of the nanocellulose can be measured by atomic force microscopy in a state dispersed in water.

[0226] The sulfur content of the nanocellulose may be about 0.6 wt% to about 1.2 wt% based on the entire nanocrystalline cellulose. The sulfur content of the nanocrystalline cellulose may be about 0.75 wt% to about 1.1 wt% based on the entire nanocellulose.

[0227] The pH of the nanocellulose may be 5 to 7. The pH of the nanocellulose may be 6 to 7.

[0228] The zeta potential of the nanocellulose may be about -25 mV to about -50 mV. The zeta potential of the nanocellulose may be about -30 mV to about -45 mV.

[0229] The nanocellulose may be included in the biodegradable polyester resin composition according to the examples at a content 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 at a content 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 at a content 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 at a content of about 0.05 part by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0230] Since the nanocellulose has the above characteristics, it can be uniformly dispersed in the biodegradable polyester resin composition according to the examples.

[0231] Since the nanocellulose has the above characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0232] 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. As a result, the nanocellulose can increase the crystallization temperature of the biodegradable polyester resin composition according to the examples.

[0233] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance characteristics.

[0234] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have an appropriate biodegradation rate.

[0235] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have an appropriate hydrolysis rate.

[0236] The biodegradable polyester resin composition according to the examples may contain a metal salt.

[0237] 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.

[0238] At least one of the metal salts may be selected from the group consisting of nitrates, sulfates, hydrochlorides, carboxylates, etc. At least one 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, silver salts, etc. At least one of the metal salts may be selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, sodium nitrate, etc.

[0239] 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).

[0240] Further, the metal salt may be selected from the group consisting of acetate, nitrate, nitride, sulfide, sulfate, sulfoxide, hydroxide, hydrate, chloride, chlorinate, and bromide.

[0241] 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.

[0242] The biodegradable polyester resin composition according to the examples may further contain a chain extender.

[0243] The chain extender may contain isocyanate.

[0244] The chain extender may be selected from at least one or more of the group consisting of monofunctional isocyanate or polyfunctional isocyanate.

[0245] The chain extender may be selected from at least one or more of 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 methylene bis(4 - isocyanatocyclohexane).

[0246] The chain extender may contain triisocyanate. The chain extender may contain tris(4 - isocyanatophenyl)methane.

[0247] 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.

[0248] The chain extender may contain a styrene copolymer. The chain extender may contain styrene glycidyl acrylate.

[0249] 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.

[0250] The chain extender may be contained in the biodegradable polyester resin composition according to the examples in a content 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 a content 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 a content of about 0.3 wt% to about 7 wt%.

[0251] 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.

[0252] 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.

[0253] In addition, the chain extender can couple the polymers contained in the biodegradable polyester resin, and the biodegradable polyester resin composition according to the examples can increase the proportion of high-molecular-weight polymers. Thereby, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0254] The biodegradable polyester resin composition according to the examples may contain an oligomer. The molecular weight of the oligomer may be about 400 to about 1300.

[0255] The oligomer may be contained in the biodegradable polyester resin composition according to the examples at about 3000 ppm to about 30000 ppm based on the entire resin composition. The oligomer may be contained in the biodegradable polyester resin composition according to the examples at about 5000 ppm to about 20000 ppm based on the entire resin composition. The oligomer may be contained in the biodegradable polyester resin composition according to the examples at about 5000 ppm to about 15000 ppm based on the entire resin composition. The oligomer may be contained in the biodegradable polyester resin composition according to the examples at about 7000 ppm to about 15000 ppm based on the entire resin composition.

[0256] 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.

[0257] The oligomer may contain an oligomer in which the molar ratio of the aliphatic dicarboxylic acid is even 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.

[0258] The oligomer can appropriately adjust the degree of hydrolysis of the biodegradable polyester resin composition according to the examples. The oligomer may be a hydrolysis regulator that appropriately adjusts the degree of hydrolysis of the biodegradable polyester resin composition according to the examples.

[0259] Also, the oligomer can appropriately adjust the degree of biodegradation of the biodegradable polyester resin composition according to the examples. The oligomer may be a biodegradation regulator that appropriately adjusts the degree of biodegradation of the biodegradable polyester resin composition according to the examples.

[0260] The biodegradable polyester resin composition according to the examples may contain a heat stabilizer. The heat stabilizer may be a phosphorus-based heat stabilizer.

[0261] The heat stabilizer may be at least one selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentamine, triethylphosphonoacetate, phosphoric acid, phosphorous acid, polyphosphric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, or triphenyl phosphine.

[0262] Also, the heat stabilizer may be an antioxidant having an antioxidant function.

[0263] The content of the heat stabilizer may be about 3000 ppm or less based on the total weight of the biodegradable polyester resin. The content of the heat stabilizer may be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the biodegradable polyester resin. By satisfying the above range of the content of the heat stabilizer, 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.

[0264] 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.

[0265] 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.

[0266] The biodegradable polyester resin composition according to the example may contain an inorganic filler. The inorganic filler is at least one selected from 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.

[0267] 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.

[0268] 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.

[0269] The inorganic filler may be included in the biodegradable polyester resin composition according to the examples 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 included in the biodegradable polyester resin composition according to the examples 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.

[0270] The inorganic filler may be included in the biodegradable polyester resin composition according to the examples in an amount of about 3,000 ppm or less based on the total weight of the composition. 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.

[0271] Since the biodegradable polyester resin composition according to the example contains the inorganic filler in the above content, it may have mechanical properties, appropriate UV resistance properties, an appropriate biodegradation rate, and an appropriate hydrolysis rate of the biodegradable polyester resin composition according to the example.

[0272] The biodegradable polyester resin composition according to the example may further contain two kinds of biodegradable resins. The biodegradable polyester resin composition according to the example may be a composite resin composition containing two or more resins, fillers, and additives.

[0273] At least one or more of the two kinds 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).

[0274] The two kinds of biodegradable resins may be contained in the biodegradable polyester resin composition according to the example in a content 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 kinds of biodegradable resins may be contained in the biodegradable polyester resin composition according to the example in a content 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 kinds of biodegradable resins may be contained in the biodegradable polyester resin composition according to the example in a content of about 20 parts by weight to about 50 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0275] The two kinds of biodegradable resins can complement the mechanical, optical, and chemical properties of the biodegradable polyester resin. Since the biodegradable polyester resin composition according to the example contains the two kinds of biodegradable resins in the above content, it may have mechanical properties, appropriate UV resistance properties, an appropriate biodegradation rate, and an appropriate hydrolysis rate of the biodegradable polyester resin composition according to the example.

[0276] In addition, 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 number of terminal carboxyl groups is adjusted within the above range and the biodegradable polyester resin composition according to the examples forms an extruded product, deterioration can be prevented and improved mechanical properties can be realized.

[0277] In addition, 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 the biodegradable polyester resin composition according to 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.

[0278] The process of manufacturing the biodegradable polyester resin composition according to the examples is as follows.

[0279] Referring to FIG. 1, the manufacturing apparatus of the biodegradable polyester resin includes a slurry stirrer 100, an esterification reaction unit 200, a polycondensation reaction unit 300, a post-treatment unit 400, a first recovery unit 510, and a second recovery unit 520.

[0280] The method for manufacturing the biodegradable polyester resin includes a step of manufacturing a slurry containing the diol and the aromatic dicarboxylic acid.

[0281] The step of manufacturing the slurry includes the step of mixing and processing the diol and the aromatic dicarboxylic acid. That is, the step of manufacturing the slurry is a pretreatment step before the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid to form a slurry. At this time, the diol may contain a biomass-based diol component.

[0282] 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.

[0283] The diol and the aromatic dicarboxylic acid can be put into the slurry stirrer 100 and stirred to produce the slurry.

[0284] By mixing, pretreating, and slurrying the diol and the aromatic dicarboxylic acid, not only can the diol and the aromatic dicarboxylic acid react uniformly, but it is also effective in promptly causing the esterification reaction, so the reaction efficiency can be enhanced.

[0285] In particular, when the aromatic dicarboxylic acid has complete crystallinity and is in powder form, such as terephthalic acid, its solubility in the diol is very low, and a homogeneous reaction may not easily occur. Therefore, the pretreatment process of slurrying plays a very important role in providing biodegradable polyester resins, sheets, films, and molded products having excellent physical properties according to embodiments of the present invention and enhancing the reaction efficiency.

[0286] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid has complete crystallinity, is a white crystal that sublimates at nearly 300 °C under normal pressure without a melting point, has a very low solubility in the diol, and it is difficult for a homogeneous reaction to occur. Therefore, when a pretreatment process is performed before the esterification reaction, since it reacts with the diol within the solid matrix of terephthalic acid, the surface area can be increased to induce a uniform reaction.

[0287] Also, when the aromatic dicarboxylic acid is dimethyl terephthalate, since the pretreatment process can make the dimethyl terephthalate in a molten state at about 142 °C to 170 °C and react it with the diol, the esterification reaction rate can be made even faster and more efficient.

[0288] On the other hand, in the pretreatment 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, pretreatment reaction conditions, etc. of the aromatic dicarboxylic acid.

[0289] For example, the aromatic dicarboxylic acid contains terephthalic acid, and the average particle size (D50) of the terephthalic acid measured by a particle size analyzer Microtrac S3500 in the particle size distribution (PSD) may be 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, for example, 20 μm to 300 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 the diol and the reaction rate.

[0290] In the pretreatment step, the diol and the aromatic dicarboxylic acid can be mixed and put into a slurry stirrer 100 (tank).

[0291] The slurry stirrer 100, for example, with an anchor type at the bottom, a height up to the agitator of 20 mm or more, and equipped with three or more rotating blades, may be more advantageous for achieving an efficient stirring effect.

[0292] For example, the height of the slurry stirrer 100 up to the agitator may be 20 mm or more, that is, there may be almost a connection between the reactor and the bottom 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 meet 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.

[0293] 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, for 10 minutes to 200 minutes.

[0294] The diol may have the same characteristics as described above.

[0295] 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.

[0296] The aromatic dicarboxylic acid may have the same characteristics as described above.

[0297] 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 1.6:1. In the pretreatment stage of manufacturing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid may be about 0.9:1 to about 1.5:1.

[0298] When the diol is introduced in an amount even larger than that of the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be easily dispersed.

[0299] In addition, an additive can be introduced into the slurry. The nanocellulose and / or the metal salt may be added to the slurry.

[0300] The method for producing the biodegradable polyester resin esterifies a slurry obtained by mixing and pre-treating a diol and an aromatic dicarboxylic acid to obtain a prepolymer, and then subjecting the prepolymer to a polycondensation reaction, whereby the structure and physical properties of the biodegradable polyester resin targeted by the embodiments of the present invention can be efficiently achieved.

[0301] The method for producing the biodegradable polyester resin includes a step of esterifying the slurry and the aliphatic dicarboxylic acid to produce a prepolymer. The slurry and the aliphatic dicarboxylic acid can react in the ester reaction section.

[0302] In the esterification reaction, by using the slurry, the reaction time can be shortened. For example, the slurry obtained in the pre-treatment step can shorten the reaction time of the ester reaction by 1.5 times or more.

[0303] The esterification reaction can be carried out at least twice or more. The prepolymer to be introduced into the polycondensation step can be formed by the esterification reaction.

[0304] In one embodiment, the esterification reaction can be carried out at once after introducing an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid into the slurry. That is, the slurry is introduced into the esterification reactor, and the esterification reaction can be carried out by introducing the aliphatic dicarboxylic acid alone, or the aliphatic dicarboxylic acid and the diol into the esterification reactor.

[0305] The diol and the aliphatic dicarboxylic acid may be added to a slurry containing the aromatic dicarboxylic acid in a slurry form.

[0306] The average particle size (D50) of the aliphatic dicarboxylic acid in the slurry of the diol and the aliphatic dicarboxylic acid may be about 50 μm to about 150 μm. The average particle size (D50) of the aliphatic dicarboxylic acid in the slurry of the diol and the aliphatic dicarboxylic acid may be about 60 μm to about 120 μm.

[0307] In the esterification reaction, the molar number of the total diol charged may be about 1.0 to about 1.8 with respect to the total molar number of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. In the esterification reaction, the molar number of the total diol charged may be about 1.1 to about 1.6 with respect to the total molar number of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0308] 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.

[0309] Also, various additives such as the nanocellulose may be added to the slurry of the diol and the aliphatic dicarboxylic acid.

[0310] The esterification reaction can be carried out at about 250 °C or lower for about 0.5 hour to about 5 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 at 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.

[0311] In one embodiment, the slurry, the aliphatic dicarboxylic acid, and the diol can be mixed to carry out a first esterification reaction. At this time, in the reaction mixture for carrying out the first esterification reaction, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be 1:0.05 to 1:0.5.

[0312] Further, after the first ester reaction, a mixture of the slurry, the aliphatic dicarboxylic acid, and the diol can be introduced into the esterification reaction section to carry out a second ester reaction together with the first ester reaction product. At this time, in the mixture introduced in the second esterification reaction, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be 0.05:1 to 0.5:1.

[0313] The first ester reaction can be carried out at 250°C or lower for 1.25 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 1.25 hours to 4 hours, 1.25 hours to 3.5 hours, or 2.5 hours to 3 hours, but is not limited thereto.

[0314] 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 2.5 hours, but is not limited thereto.

[0315] In the first esterification reaction and the second esterification reaction, the reaction temperature, reaction time, and the contents of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid introduced are respectively adjusted, so that the ratio of the number of the first block and the second block, the ratio of the alternation, the ratio of the hard segment, and the ratio of the soft segment can be adjusted. Further, when the esterification reaction is carried out separately as the first esterification reaction and the second esterification reaction, the overall esterification reaction can be precisely controlled. Thereby, when the esterification reaction is carried out separately, the reaction stability and reaction uniformity of the esterification reaction can be improved.

[0316] Further, in the second esterification reaction, the branching agent can be further introduced. That is, the slurry, the mixture of the aliphatic dicarboxylic acid, the diol, the branching agent, and the product of the first esterification reaction can react to form the prepolymer. The characteristics and content of the branching agent may be the same as those described above.

[0317] After the second esterification reaction is completed, a third esterification 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 product of the second esterification reaction, and the third esterification reaction can be carried out.

[0318] The monomer composition may be added to the product of the second esterification reaction at a content of about 0.5 parts by weight to about 10 parts by weight based on 100 parts by weight of the product of the second esterification reaction.

[0319] Further, 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.

[0320] Also, 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.

[0321] The third esterification reaction can be carried out at about 250 °C or lower for 0.1 to 0.5 hours. 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 to 60 minutes, 10 to 50 minutes or 10 to 40 minutes, it is not limited thereto.

[0322] A prepolymer can be formed by the third esterification reaction.

[0323] When the third esterification reaction is carried out under the above process conditions using the monomer composition as described above, the crosslinking ratio, the ratio of the hard segment, and the ratio of the soft segment can be appropriately adjusted.

[0324] In the third esterification reaction, the product of the second esterification reaction 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. Thereafter, the product of the second esterification reaction and the product of the third esterification reaction can be mixed with each other to produce the prepolymer. At this time, the product of the third esterification reaction can be mixed with the product of the second esterification reaction in an amount of about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the product of the second esterification reaction to produce the prepolymer.

[0325] 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 800 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.

[0326] 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).

[0327] The reinforcing material, the branching agent, the ester polyol, or the metal salt may be introduced together with the slurry before the esterification reaction. The reinforcing material, the branching agent, the ester polyol, or the metal salt may be introduced into the esterification reaction section 200 during the esterification reaction. The reinforcing material, the branching agent, the ester polyol, or the metal salt may be introduced into the ester reaction product after the esterification reaction. Also, the reinforcing material, the branching agent, the ester polyol, or the metal salt may be introduced together with the aliphatic dicarboxylic acid. Also, the reinforcing material, the branching agent, the ester polyol, or the metal salt may be introduced into the esterification reaction section 200 after the first ester reaction and before the second ester reaction.

[0328] Since the reinforcing material and / or the metal salt are introduced into the esterification reaction, the reinforcing material and / or the metal salt may be uniformly dispersed in the biodegradable polyester resin.

[0329] The reinforcing material may have the characteristics described above. In particular, the nanocellulose can be used as the reinforcing material.

[0330] 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 pretreated by a bead mill or ultrasonic waves with water-dispersed nanocellulose.

[0331] For now, 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 eccentric wear, reduces bead wear, and is easy to maintain, it is not limited thereto.

[0332] The bead mill pretreatment can be carried out using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0333] Specifically, the bead mill pretreatment can be carried out 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.

[0334] By having the diameter of the beads satisfy the above range, the dispersibility of the nanocellulose can be further improved. If the diameter of the beads exceeds the above range, the average particle size and particle size deviation of the nanocellulose may increase, resulting in lower dispersibility.

[0335] In addition, it is preferable to use beads with a specific gravity higher than that of nanocellulose in the bead mill pretreatment in terms of sufficient energy transfer. 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 higher specific gravity than 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.

[0336] 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.

[0337] The ultrasonic pretreatment can be performed at an output of 30000 J / s or less for a time of less than 30 minutes. For example, the ultrasonic pretreatment can be performed at an output of 25000 J / s or less or 22000 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 output exceeds the above range, on the contrary, the nanoparticles may re-aggregate and the dispersibility may decrease.

[0338] The nanocellulose according to the embodiment may be subjected to bead mill pretreatment or ultrasonic pretreatment. Or, 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 ultrasonic pretreatment after bead mill pretreatment in terms of preventing re-aggregation and improving dispersibility.

[0339] The nanocellulose according to the embodiment may be subjected to bead mill pretreatment or ultrasonic pretreatment. Or, 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 ultrasonic pretreatment after bead mill pretreatment in terms of preventing re-aggregation and improving dispersibility.

[0340] Since the nano-cellulose contains ionically bonded metal, its dispersibility in water is very high. Further, a water dispersion with a very high degree of dispersion of the nano-cellulose can be obtained by the bead mill pretreatment and / or the ultrasonic pretreatment. The content of the nano-cellulose in the aqueous dispersion of the nano-cellulose may be from about 1 wt% to about 50 wt%.

[0341] 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.

[0342] Further, 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.

[0343] 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.

[0344] Also, the content of the catalyst may be about 100 ppm to 2000 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 1600 ppm, about 150 ppm to about 1400 ppm, about 200 ppm to about 1200 ppm, or about 250 ppm to about 1100 ppm. By satisfying the above range of the catalyst content, the physical properties can be further improved.

[0345] Also, 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. Also, 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.

[0346] The characteristics of the heat stabilizer may be the same as those described above.

[0347] The content of the heat stabilizer may be 3,000 ppm or less based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Specifically, the content of the heat stabilizer may be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By satisfying the above range of the heat stabilizer content, the degradation 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.

[0348] 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 can 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.

[0349] 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, the inorganic filler can be added and stabilized, and then 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 can be uniformly dispersed in the biodegradable polyester resin.

[0350] 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 apply a vacuum pressure to the esterification reaction section 200 or perform reflux to recover the by-products generated in the esterification reaction.

[0351] 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.

[0352] 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.

[0353] 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, 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 for about 1.5 hours to about 5 hours, about 2 hours to about 4.5 hours, or about 2 hours to about 4 hours.

[0354] Also, the polycondensation reaction may include a primary polycondensation and a secondary polycondensation.

[0355] For example, the primary polycondensation is carried out at about 260°C or less, about 250°C or less, 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, and 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.

[0356] Also, the secondary polycondensation is 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 less, about 0.8 torr or less, about 0.6 torr or less, 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, and 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.

[0357] Further, 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, 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 one or more selected from the group consisting of polymerization catalysts such as antimony trioxide, antimony trioxide, or tetrabutyl titanate can be further added to the prepolymer.

[0358] 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 35,000 g / mol or more, or about 40,000 g / mol to about 90,000 g / mol. By satisfying the above range of the number average molecular weight of the polymer, the physical properties, impact resistance, durability, and moldability can be further improved.

[0359] 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.

[0360] 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.

[0361] 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 reacts with the hydrolysis-resistant agent and / or the chain extender.

[0362] The chain extender may have the same characteristics as described above.

[0363] Thereby, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis and a high degree of biodegradability.

[0364] Thereafter, pellets can be produced from the polymer.

[0365] 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.

[0366] The cutting step can be carried out without limitation using any 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.

[0367] The pellets can undergo further post-treatment steps. The pellets can be introduced into the post-treatment unit 400 to perform the post-treatment steps.

[0368] The post-treatment steps 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 extrude them again. That is, the post-treatment unit 400 may include an extruder such as a twin-screw extruder.

[0369] The post-treatment step temperature may be about 230 °C to about 270 °C. The post-treatment step temperature may be about 230 °C to about 260 °C. The post-treatment step temperature may be about 240 °C to about 265 °C. The post-treatment step temperature may be about 240 °C to about 260 °C.

[0370] 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.

[0371] 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.

[0372] The crystallinity of the pellets can be improved in the post-treatment process. Also, the content of the residues contained in the pellets can be adjusted in the post-treatment process. In particular, the content of the oligomers contained in the pellets can be adjusted by the post-treatment process. The content of the residual solvent contained in the pellets can be adjusted by the post-treatment process.

[0373] Thereby, the post-treatment process can appropriately adjust the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable polyester resin.

[0374] 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, or the other additives can be compounded with the biodegradable polyester resin and the two biodegradable resins.

[0375] The compounding process is as follows.

[0376] 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. Thereafter, the melt-mixed biodegradable polyester resin composition is extruded, cooled, cut, and re-pelletized. Through such a process, a biodegradable polyester resin composition according to an example can be produced by being compounded with the two biodegradable resins.

[0377] Differently, the inorganic filler, the heat stabilizer, the color corrector, the metal salt, and the other additives may be those added during the process of polymerizing the biodegradable polyester resin.

[0378] A biodegradable polyester film can be produced by the biodegradable polyester resin composition according to an example.

[0379] 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.

[0380] The biodegradable polyester film according to an example may have a hydrolysis degree and a biodegradation degree substantially the same as those of the biodegradable polyester resin composition described above.

[0381] On the other hand, the biodegradable polyester film can be produced using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0382] Specifically, the method for manufacturing the biodegradable polyester film may include a step of manufacturing a biodegradable resin composition according to an example, and a step of drying and melt-extruding the biodegradable resin composition.

[0383] In the step of drying and melt-extruding the biodegradable resin composition, the drying can be performed at about 60°C to about 100°C for about 2 hours to about 12 hours. Specifically, the drying can be performed 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 manufactured biodegradable polyester film or molded product can be further improved.

[0384] In the step of drying and melt-extruding, the melt-extrusion can be performed at a temperature of about 270°C or lower. For example, the melt-extrusion can be performed at a temperature of about 265°C or lower, about 260°C or lower, about 255°C or lower, about 150°C to about 270°C, about 150°C to about 255°C, or about 150°C to about 240°C. The melt-extrusion can be performed in a blown film process. The melt-extrusion can be performed with a T-die.

[0385] Also, the film manufacturing process may be a calendaring process.

[0386] Biodegradable polyester molded product A biodegradable polyester molded product can be manufactured using the biodegradable polyester resin.

[0387] Specifically, the molded product can be manufactured by molding the biodegradable polyester resin composition by known methods in the industry such as extrusion and injection. The molded product may be, but is not limited to, an injection molded product, an extrusion molded product, a thin film molded product, a blow molding, or a blow molded product, a 3D filament, an interior building material, etc.

[0388] 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, pay-by-weight garbage bags, etc., or may be in the form of fibers used for textiles, knitted fabrics, non-woven fabrics, ropes, etc. Further, as shown in FIG. 2, it may be a disposable container 10 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, eating plates, forks, etc.

[0389] In particular, since the molded article can be formed from 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 is used for packaging materials of products stored and transported at low temperatures, automotive interior materials requiring durability, garbage bags, mulching films, and disposable products, and can exhibit excellent characteristics.

[0390] The biodegradable polyester resin composition according to the example may be one whose biodegradability is measured by the following method.

[0391] In order to measure the biodegradability, the biodegradable resin composition according to the above 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 elapsed, the number average molecular weight of the biodegradable polyester resin composition according to the example was measured using gel permeation chromatography (GPC). 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.

[0392] The biodegradability may be represented by the following Mathematical formula 10.

[0393] [Mathematical formula 10] JPEG2025522290000024.jpg12144

[0394] 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).

[0395] 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.

[0396] 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.

[0397] Also, the manufacturer of the compost may be Taeheung F&G, and the product name of the compost may be Jisangto (by-product fertilizer grade 1 compost).

[0398] 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 5 mm × 5 mm to produce flakes. The flakes can be mixed with the compost to conduct the biodegradation acceleration test.

[0399] In the biodegradable polyester resin composition according to the example, the biodegradability after one week may be about 40% to about 70%. In the biodegradable polyester resin composition according to the example, the biodegradability after one week may be about 45% to about 65%. In the biodegradable polyester resin composition according to the example, the biodegradability after one week may be about 47% to about 63%. In the biodegradable polyester resin composition according to the example, the biodegradability after one week may be about 49% to about 62%.

[0400] 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%.

[0401] 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%.

[0402] 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%.

[0403] 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%.

[0404] 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.

[0405] Since the biodegradable polyester resin composition according to the example has the biodegradation degree and the increase rate of the biodegradation degree as described above, it may have appropriate durability in the actual living area and may have a high biodegradation degree when discarded after use.

[0406] The biodegradable polyester resin composition according to the examples can have its degree of hydrolysis measured by the following method.

[0407] In order to measure the degree of hydrolysis, the biodegradable resin composition according to the above examples 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 examples is measured using gel permeation chromatography (GPC). The degree of hydrolysis is derived from 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 by the initial number average molecular weight.

[0408] The degree of hydrolysis may be represented by the following Equation 11.

[0409] [Equation 11] JPEG2025522290000025.jpg13155

[0410] Here, the biodegradable polyester resin composition according to the examples is immersed in water at 80°C and then undergoes a hydrolysis acceleration test for a certain period. 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 are measured by gel permeation chromatography (GPC).

[0411] The degree of hydrolysis is derived from 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 by the initial number average molecular weight.

[0412] Also, when the degree of hydrolysis is measured, the biodegradable polyester resin composition according to the examples is made into a sheet having a thickness of about 300 μm. Then, the manufactured sheet is cut into a size of about 5 mm × 5 mm to produce flakes. The flakes can be immersed in the warm water to carry out the hydrolysis acceleration test.

[0413] 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%.

[0414] 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%.

[0415] 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%.

[0416] 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%.

[0417] 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.

[0418] In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after nine weeks may be about 95% or more. In the biodegradable polyester resin composition according to the examples, the degree of hydrolysis after nine weeks may be about 96% or more.

[0419] 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.

[0420] The biodegradable polyester resin composition according to the examples may have a wet hardness reduction rate. The wet hardness reduction rate is a value obtained by dividing the difference between the initial hardness before immersion and the wet hardness after immersion by the initial hardness after the biodegradable polyester resin composition is immersed in water at a constant temperature for a certain period of time.

[0421] The wet hardness reduction rate can be derived by the following formula 12.

[0422] [Formula 12] JPEG2025522290000026.jpg15147

[0423] The wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour may be 12% to 30%. The wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour may be 12% to 25%. The wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour may be 14% to 25%. The wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour may be 15% to 23%.

[0424] The wetness hardness reduction rate after immersion at the temperature of 30°C for 1 hour can be measured by the following measurement method. First, the biodegradable polyester resin composition is processed to produce a polyester block having a thickness of about 2.5 mm. The initial hardness of the polyester block is measured before immersion, and after the polyester block is immersed in water at about 30°C for about 1 hour, the wetness hardness of the polyester block is immediately measured. Then, the wetness hardness reduction rate after immersion at the temperature of 30°C for 1 hour can be derived by the following Equation 12.

[0425] The biodegradable polyester resin composition can be dried at a temperature of about 80°C for about 20 minutes, placed in a stainless steel frame, and compressed at a temperature of about 210°C under a pressure of about 10 MPa for about 5 minutes to produce a polyester block having a thickness of about 2.5 mm.

[0426] The initial hardness may be about 30 to about 45 in Shore D hardness. The initial hardness may be about 33 to about 43 in Shore D hardness. The initial hardness may be about 35 to about 41 in Shore D hardness.

[0427] The wetness hardness after immersion at the temperature of 30°C for 1 hour may be about 25 to about 40 in Shore D hardness. The wetness hardness after immersion at the temperature of 30°C for 1 hour may be about 27 to about 37 in Shore D hardness. The wetness hardness after immersion at the temperature of 30°C for 1 hour may be about 30 to about 35 in Shore D hardness.

[0428] The wetness hardness reduction rate after immersion at the temperature of 30°C for 0.5 hour may be about 12% to about 30%. The wetness hardness reduction rate after immersion at the temperature of 30°C for 0.5 hour may be about 12% to about 25%. The wetness hardness reduction rate after immersion at the temperature of 30°C for 0.5 hour may be about 14% to about 25%. The wetness hardness reduction rate after immersion at the temperature of 30°C for 0.5 hour may be about 15% to about 23%.

[0429] The wet hardness after immersion at the temperature of 30°C for 0.5 hours may be about 25 to about 40 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 0.5 hours may be about 27 to about 37 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 0.5 hours may be about 30 to about 35 in Shore D hardness.

[0430] The deviation between the wet hardness reduction rate after immersion at the temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at the temperature of 30°C for 0.5 hours may be about 10% or less. The deviation between the wet hardness reduction rate after immersion at the temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at the temperature of 30°C for 0.5 hours is the value obtained by dividing the absolute value of the difference between the wet hardness after immersion at the temperature of 30°C for 1 hour and the wet hardness after immersion at the temperature of 30°C for 0.5 hours by the initial hardness. The deviation between the wet hardness reduction rate after immersion at the temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at the temperature of 30°C for 0.5 hours may be about 7% or less. The deviation between the wet hardness reduction rate after immersion at the temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at the temperature of 30°C for 0.5 hours may be about 5% or less.

[0431] The wet hardness reduction rate after immersion at the temperature of 30°C for 18 hours may be about 12% to about 30%. The wet hardness reduction rate after immersion at the temperature of 30°C for 18 hours may be about 12% to about 25%. The wet hardness reduction rate after immersion at the temperature of 30°C for 18 hours may be about 14% to about 25%. The wet hardness reduction rate after immersion at the temperature of 30°C for 18 hours may be about 15% to about 23%.

[0432] The wet hardness after immersion at the temperature of 30°C for 18 hours may be about 25 to about 40 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 18 hours may be about 27 to about 37 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 18 hours may be about 30 to about 35 in Shore D hardness.

[0433] The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 18 hours may be about 10% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 18 hours may be about 7% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 18 hours may be about 5% or less.

[0434] The wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 13% to about 31%. The wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 13% to about 26%. The wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 15% to about 26%. The wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 16% to about 24%.

[0435] The wet hardness after immersion at a temperature of 30°C for 24 hours may be about 24 to about 39 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 24 hours may be about 26 to about 36 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 24 hours may be about 29 to about 34 in Shore D hardness.

[0436] The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 10% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 7% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours may be about 5% or less.

[0437] The rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 13% to about 31%. The rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 13% to about 26%. The rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 14% to about 26%. The rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 15% to about 24%.

[0438] The wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 24 to about 40 in Shore D hardness. The wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 26 to about 37 in Shore D hardness. The wet hardness after immersion at a temperature of 50°C for 1 hour may be from about 29 to about 35 in Shore D hardness.

[0439] The deviation between the rate of decrease in wet hardness after immersion at a temperature of 30°C for 1 hour and the rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be about 10% or less. The deviation between the rate of decrease in wet hardness after immersion at a temperature of 30°C for 1 hour and the rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be about 7% or less. The deviation between the rate of decrease in wet hardness after immersion at a temperature of 30°C for 1 hour and the rate of decrease in wet hardness after immersion at a temperature of 50°C for 1 hour may be about 5% or less.

[0440] The rate of decrease in wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 14% to about 31%. The rate of decrease in wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 14% to about 26%. The rate of decrease in wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 15% to about 26%. The rate of decrease in wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 15% to about 24%.

[0441] The wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 24 to about 39 in Shore D hardness. The wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 25 to about 36 in Shore D hardness. The wet hardness after immersion at a temperature of 70°C for 1 hour may be from about 28 to about 35 in Shore D hardness.

[0442] The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 70°C for 1 hour may be about 10% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 70°C for 1 hour may be about 7% or less. The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 1 hour and the wet hardness reduction rate after immersion at a temperature of 70°C for 1 hour may be about 5% or less.

[0443] The biodegradable polyester resin composition according to the examples has an appropriate wet hardness reduction rate as described above. As a result, the biodegradable polyester resin composition according to the examples may contain appropriate moisture in a high-humidity environment or in water such as the sea at the time of disposal. As a result, the biodegradable polyester resin composition according to the examples can be easily decomposed in a high-humidity environment, particularly in water.

[0444] In addition, the biodegradable polyester resin composition according to the examples may have an appropriate wet hardness reduction rate and an appropriate initial hydrolysis resistance. As a result, the biodegradable polyester resin composition according to the examples can be easily biodegradable after being used by the user and discarded, while maintaining appropriate mechanical and chemical properties within the user's usage period.

[0445] In addition, the biodegradable polyester resin composition according to the examples can be easily biodegradable in high-humidity soil.

[0446] In addition, when the biodegradable polyester resin composition according to the examples is discarded in an aquatic environment such as the ocean, a river, or a lake, moisture and inorganic ions can easily penetrate into the biodegradable polyester resin composition according to the examples. As a result, the biodegradable polyester resin composition according to the examples can be easily biodegradable even in water such as the ocean, a river, or a lake.

[0447] The biodegradable polyester resin composition according to the example contains a polyester resin having an appropriate alternating ratio. The content of the diol bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid may be appropriate.

[0448] Thereby, the biodegradable polyester resin may have a structure in which the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid are appropriately arranged alternately. Thereby, the biodegradable polyester resin may have improved crystal properties, and the biodegradable polyester resin composition according to the example may have improved thermal and mechanical properties.

[0449] Further, since the biodegradable polyester resin has a structure in which the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid are appropriately arranged alternately, the aromatic and aliphatic groups may appropriately cross within the molecule of the biodegradable polyester resin. Thereby, the biodegradable polyester resin composition according to the example may have an appropriate degree of hydrolysis, an improved degree of biodegradability, and an appropriate rate of decrease in wet hardness.

[0450] Further, since the biodegradable polyester resin has the above molecular structure, it may have appropriate moisture resistance and solvent resistance. Thereby, the biodegradable polyester resin composition according to the example may have improved printability.

[0451] Therefore, the biodegradable polyester resin composition according to the example has improved physical properties during actual use and can be easily biodegraded after use.

[0452] The biodegradable polyester resin composition according to the example includes a weight swelling ratio. The weight swelling ratio may be a value obtained by dividing the difference between the weight after immersion in an organic solvent and the initial weight by the initial weight. When the weight swelling ratio is measured, the biodegradable polyester resin composition according to the example may be processed into the form of the above-described biodegradable polyester sheet and immersed in the solvent. Further, when the weight after immersion is measured, the solvent remaining on the surface of the biodegradable polyester sheet is sufficiently removed. Further, when the weight is measured after the immersion, the biodegradable polyester sheet may be immersed in a solvent at room temperature.

[0453] The weight swelling ratio can be calculated by the following mathematical formula 13.

[0454] [Mathematical formula 13] JPEG2025522290000027.jpg17145

[0455] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after being immersed in acetone for 2 hours.

[0456] In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may be 15% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may be 12% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may be 10% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may have a minimum value of about 0.1%, about 1%, about 1.5%, or about 2.5%. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 2 hours may be about 1% to about 18%, about 2% to about 15%, about 3% to about 15%, or about 3.2% to about 15%.

[0457] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after being immersed in acetone for 18 hours.

[0458] In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may be 15% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may be 12% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may be 10% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may have a minimum value of about 0.1%, about 1%, about 1.5%, or about 2.5%. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after being immersed in acetone for 18 hours may be about 1% to about 18%, about 2% to about 15%, about 3% to about 15%, or about 3.2% to about 15%.

[0459] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after being immersed in acetone for 24 hours.

[0460] In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may be 15% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may be 12% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may be 10% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may have a minimum value of about 0.1%, about 1%, about 1.5% or about 2.5%. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetone for 24 hours may be about 1% to about 18%, about 2% to about 15%, about 3% to about 15%, or about 3.2% to about 15%.

[0461] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after immersion in acetonitrile for 2 hours.

[0462] In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 2 hours may be 20% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 2 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 2 hours may be 15% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 2 hours may be 13% or less. The weight swelling ratio after immersion in the acetonitrile for 2 hours may have a minimum value of about 0.1%, about 2%, about 3.5% or about 4.5%. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 2 hours may be about 1% to about 20%, about 4.5% to about 20%, about 6.5% to about 20%, or about 7% to about 15%.

[0463] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after immersion in acetonitrile for 18 hours.

[0464] In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 18 hours may be 20% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 18 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 18 hours may be 15% or less. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 18 hours may be 13% or less. The weight swelling ratio after immersion in the acetonitrile for 18 hours may have a minimum value of about 0.1%, about 4%, about 5.5% or about 6.5%. In the biodegradable polyester resin composition according to the example, the weight swelling ratio after immersion in the acetonitrile for 18 hours may be about 1% to about 20%, about 5.5% to about 20%, about 6.5% to about 20%, or about 7% to about 15%.

[0465] The biodegradable polyester resin composition according to the example may have a weight swelling ratio after immersion in acetonitrile for 24 hours.

[0466] In the biodegradable polyester resin composition according to the embodiment, the weight swelling ratio after immersion in the acetonitrile for 24 hours may be 20% or less. In the biodegradable polyester resin composition according to the embodiment, the weight swelling ratio after immersion in the acetonitrile for 24 hours may be 18% or less. In the biodegradable polyester resin composition according to the embodiment, the weight swelling ratio after immersion in the acetonitrile for 24 hours may be 15% or less. In the biodegradable polyester resin composition according to the embodiment, the weight swelling ratio after immersion in the acetonitrile for 24 hours may be 13% or less. The weight swelling ratio after immersion in the acetonitrile for 24 hours may have a minimum value of about 0.1%, about 4%, about 6.5%, or about 7%. In the biodegradable polyester resin composition according to the embodiment, the weight swelling ratio after immersion in the acetonitrile for 24 hours may be about 1% to about 20%, about 6.5% to about 20%, about 7% to about 20%, or about 7.5% to about 15%.

[0467] Also, the biodegradable polyester resin composition according to the embodiment includes a volume swelling ratio. The volume swelling ratio may be a value obtained by dividing the difference between the volume after immersion in an organic solvent and the initial volume by the initial volume. When the volume swelling ratio is measured, the biodegradable polyester resin composition according to the embodiment is processed into the form of the biodegradable polyester sheet described above and can be immersed in the solvent. Also, when the volume after immersion is measured, the solvent remaining on the surface of the biodegradable polyester sheet is sufficiently removed. Also, when the volume after immersion is measured, the biodegradable polyester sheet can be immersed in a solvent at room temperature.

[0468] The volume swelling ratio can be derived by the following Mathematical Formula 14.

[0469] [Mathematical Formula 14] JPEG2025522290000028.jpg17140

[0470] The biodegradable polyester resin composition according to the embodiment may have a volume swelling ratio after immersion in acetone for 2 hours.

[0471] In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 2 hours may be 30% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 2 hours may be 25% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 2 hours may be 20% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 2 hours may be 18% or less. The volume swelling ratio after immersion in the acetone for 2 hours may have a minimum value of about 5%, about 10%, about 11% or about 12%. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 2 hours may be about 5% to about 30%, about 11% to about 30%, about 12% to about 30%, or about 13% to about 20%.

[0472] The biodegradable polyester resin composition according to the example may have a volume swelling ratio after immersion in acetone for 18 hours.

[0473] In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be 30% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be 25% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be 20% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be 18% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be 18% or less. The volume swelling ratio after immersion in the acetone for 18 hours may have a minimum value of about 5%, about 12%, about 13% or about 14%. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetone for 18 hours may be about 5% to about 30%, about 12% to about 30%, about 13% to about 30%, or about 14% to about 18%.

[0474] The biodegradable polyester resin composition according to the example may have a volume swelling ratio after immersion in acetone for 24 hours.

[0475] In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetone for 24 hours may be 30% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetone for 24 hours may be 25% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetone for 24 hours may be 20% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetone for 24 hours may be 18% or less. The volume swelling rate after immersion in the acetone for 24 hours may have a minimum value of about 5%, about 12%, about 13% or about 14%. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetone for 24 hours may be about 5% to about 30%, about 12% to about 30%, about 13% to about 30%, or about 14% to about 25%.

[0476] The biodegradable polyester resin composition according to the example may have a volume swelling rate after immersion in acetonitrile for 2 hours.

[0477] In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetonitrile for 2 hours may be 30% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetonitrile for 2 hours may be 25% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetonitrile for 2 hours may be 23% or less. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetonitrile for 2 hours may be 20% or less. The volume swelling rate after immersion in the acetonitrile for 2 hours may have a minimum value of about 5%, about 12%, about 13% or about 14%. In the biodegradable polyester resin composition according to the example, the volume swelling rate after immersion in the acetonitrile for 2 hours may be about 5% to about 30%, about 12% to about 30%, about 13% to about 30%, or about 14% to about 25%.

[0478] The biodegradable polyester resin composition according to the examples may have a volume swelling ratio after being immersed in acetonitrile for 18 hours.

[0479] In the biodegradable polyester resin composition according to the examples, the volume swelling ratio after being immersed in the acetonitrile for 18 hours may be 30% or less. In the biodegradable polyester resin composition according to the examples, the volume swelling ratio after being immersed in the acetonitrile for 18 hours may be 25% or less. In the biodegradable polyester resin composition according to the examples, the volume swelling ratio after being immersed in the acetonitrile for 18 hours may be 23% or less. In the biodegradable polyester resin composition according to the examples, the volume swelling ratio after being immersed in the acetonitrile for 18 hours may be 20% or less. The volume swelling ratio after being immersed in the acetonitrile for 18 hours may have a minimum value of about 5%, about 12%, about 13% or about 14%. In the biodegradable polyester resin composition according to the examples, the volume swelling ratio after being immersed in the acetonitrile for 18 hours may be about 5% to about 30%, about 12% to about 30%, about 13% to about 30%, or about 14% to about 25%.

[0480] The biodegradable polyester resin composition according to the examples may have a volume swelling ratio after being immersed in acetonitrile for 24 hours.

[0481] In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetonitrile for 24 hours may be 30% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetonitrile for 24 hours may be 25% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetonitrile for 24 hours may be 23% or less. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetonitrile for 24 hours may be 20% or less. The volume swelling ratio after immersion in the acetonitrile for 24 hours may have a minimum value of about 5%, about 12%, about 13% or about 14%. In the biodegradable polyester resin composition according to the example, the volume swelling ratio after immersion in the acetonitrile for 24 hours may be about 5% to about 25%, about 12% to about 28%, about 13% to about 28%, or about 14% to about 25%.

[0482] The biodegradable polyester resin composition according to the example has appropriately low weight swelling ratio and volume swelling ratio with respect to the organic solvent as described above. The biodegradable polyester resin composition according to the example may have a low swelling ratio with respect to organic solvents such as acetone and acetonitrile.

[0483] Accordingly, the biodegradable polyester resin composition according to the example may have high solvent resistance. Therefore, even when exposed to an organic solvent or the like, improved mechanical properties can be maintained.

[0484] Also, the biodegradable polyester resin composition according to the example may have an appropriately low swelling ratio and an appropriate initial hydrolysis resistance. Accordingly, the biodegradable polyester resin composition according to the example can be easily biodegraded at the time of disposal after use by the user while maintaining appropriate mechanical properties and chemical properties within the user's usage period.

[0485] Also, the acid value of the biodegradable polyester resin composition according to the examples may be from 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 from about 0.5 mgKOH / g to about 2.5 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be from about 0.5 mgKOH / g to about 2.3 mgKOH / g.

[0486] Since the biodegradable polyester resin composition according to the examples has an acid value in the above range, it may have hydrolysis degree characteristics and biodegradability characteristics as described above.

[0487] Also, 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 from 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 from 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 from 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 from about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples.

[0488] Also, 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 from 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 from 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 from 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 from about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0489] Since the contents of the nitrogen element and / or the metal element are as described above, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis, an appropriate degree of biodegradability, an appropriate wet hardness, an appropriate weight swelling ratio, an appropriate volume swelling ratio, and appropriate surface characteristics.

[0490] Also, the biodegradable polyester resin composition according to the examples may have surface tension, water contact angle, diode methane contact angle, surface free energy, dispersity, and polarity.

[0491] The surface tension, the water contact angle, the diode methane contact angle, the surface free energy, the dispersity, and the polarity can be measured on the surface of the polyester sheet.

[0492] 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.

[0493] 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°.

[0494] In the biodegradable polyester resin composition according to the examples, the diode methane contact angle may be about 20° to about 40°. In the biodegradable polyester resin composition according to the examples, the diode methane contact angle may be about 20° to about 35°.

[0495] In the biodegradable polyester resin composition according to the embodiment, the surface free energy may be about 40 mN / m to about 60 mN / m. In the biodegradable polyester resin composition according to the embodiment, the surface free energy may be about 42 mN / m to about 55 mN / m.

[0496] In the biodegradable polyester resin composition according to the embodiment, the dispersity may be about 35 mN / m to about 55 mN / m. In the biodegradable polyester resin composition according to the embodiment, the dispersity may be about 40 mN / m to about 50 mN / m.

[0497] In the biodegradable polyester resin composition according to the embodiment, the polarity may be about 2 mN / m to about 8 mN / m. In the biodegradable polyester resin composition according to the embodiment, the polarity may be about 3 mN / m to about 7 mN / m.

[0498] The biodegradable polyester resin composition according to the embodiment has the surface tension, the water contact angle, the diode methane contact angle, the surface free energy, the dispersity, and the polarity within the ranges as described above 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. Accordingly, the biodegradable polyester resin composition according to the embodiment may have an appropriate degree of hydrolysis and an appropriate degree of biodegradation.

[0499] The above content will be described in more detail with reference to 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.

[0500] <Production Example> Production of Pretreated Cellulose Nanocrystal 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 ultrasonically treated for 3 minutes at an output of 20,000 J / s using a tip-type ultrasonic disperser to produce pretreated nanocellulose.

[0501] Metal salts: magnesium acetate, potassium acetate Chain extender: hexamethylene diisocyanate Ester polyol: U-1615, Union Kasei Co., Ltd. Polycaprolactone diol (189421, Sigma-Aldrich) Branching agent: glycerol, trimellitic anhydride

[0502] <Example> Example 1 Production of biodegradable polyester resin First stage: The stage of obtaining a slurry by pretreatment As shown in Table 1, magnesium acetate, a branching agent, an ester polyol, pretreated nanocellulose, 1,4-butanediol (1,4-BDO), and terephthalic acid (TPA) were mixed at a molar ratio of (1,4-BDO:TPA) 1.2:1, and without a catalyst, they were put into a slurry tank (the bottom of the slurry tank is of an anchor type, the height to the agitator is 40 mm, and it is equipped with three rotating blades). At this time, the D50 of the terephthalic acid (TPA) was 150 μm, and the standard deviation (SD) with respect to the D50 of the terephthalic acid (TPA) was 30.

[0503] Next, the mixture was stirred at 60 °C and 100 rpm for 1 hour for pretreatment to obtain a slurry without phase separation.

[0504] Second stage: The stage of obtaining a prepolymer Approximately 256 parts by weight of the slurry obtained in the first stage, approximately 18 parts by weight of the 1,4 - butanediol, and approximately 29.2 parts by weight of adipic acid (a mixture with a molar ratio of 1,4 - butanediol, terephthalic acid, and adipic acid of 1.2:1:0.2) were charged into the reactor via a feed line. After charging 250 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), which is a titanium - based catalyst, a primary esterification reaction was carried out at 220 °C and atmospheric pressure for about 2 hours until 95% of the by - product water was discharged.

[0505] A mixture of approximately 16.4 parts by weight of slurry, approximately 90 parts by weight of 1,4 - butanediol (1,4 - BDO), and approximately 146 parts by weight of adipic acid (AA) (a mixture with a molar ratio of 1,4 - butanediol, terephthalic acid, and adipic acid of 1.064:0.064:1) was added to the reaction product. After adding 200 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), which is a titanium - based catalyst, based on the total weight of the reaction product and the additional mixture, a secondary esterification reaction was carried out at 210 °C and atmospheric pressure for about 2 hours until 95% of the by - product water was discharged, and a prepolymer having a number - average molecular weight of 1200 g / mol was produced.

[0506] Step 3: The step of carrying out a polycondensation reaction 5 wt% of ester polyol, 400 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), which is a titanium - based catalyst, and 500 ppm of triethylene phosphate stabilizer were added to the prepolymer based on the total weight of the prepolymer, and it was stabilized for about 10 minutes. Then, after raising the temperature of the reaction mixture to 250 °C, a polycondensation reaction was carried out at 0.5 torr for 4 hours to produce a polymer having a number - average molecular weight of 55000 g / mol.

[0507] Then, the chain extender was added to the polymer, uniformly mixed, and a chain - extension reaction was carried out at a temperature of about 240 °C for about 10 minutes.

[0508] After that, the polymer was cooled to 5 °C and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0509] Examples 2 to 7 and Comparative Examples 1 and 2 As shown in Tables 1 to 3 below, the contents of the magnesium acetate, the branching agent, the ester polyol, the polyvalent carboxylic acid, and the chain extender, and the composition and process conditions of the reactants in the primary esterification reaction and the secondary esterification reaction are different. Except for the above contents and processes, other processes were carried out substantially with reference to Example 1.

[0510] Examples 8 to 15 and Comparative Examples First stage: The stage of obtaining a slurry by pretreatment As shown in Table 4, potassium acetate, glycerol, polycaprolactone diol, pretreated nanocellulose, 1,4-butanediol (1,4-BDO), and terephthalic acid (TPA) were mixed at a molar ratio of 1,4-BDO:TPA of 1.2:1, and without a catalyst, they were put into a slurry tank (the bottom of the slurry tank is of an anchor type, the height to the agitator is 40 mm, and it is equipped with three rotating blades). At this time, the D50 of the terephthalic acid (TPA) was 130 μm.

[0511] Next, the mixture was stirred at 60°C and 100 rpm for 1 hour for pretreatment to obtain a slurry without phase separation.

[0512] As shown in Tables 4 to 6 below, the contents of the potassium acetate, the glycerol, the polycaprolactone diol, the glycerol, and the chain extender, and the composition and process conditions of the reactants in the primary esterification reaction and the secondary esterification reaction are different. Except for the above contents and processes, other processes were carried out substantially with reference to Example 1.

[0513] Manufacture of biodegradable polyester sheet After preparing two Teflon sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was placed on one Teflon sheet. After putting about 7 g of the manufactured polyester resin pellets into the stainless steel (SUS) frame (area 12 cm × 12 cm), it was covered with the other Teflon sheet and placed in the center of a hot press (Hot Press, manufacturer: Withrap, model name: 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 detached, and immediately cooled with water at about 20 °C for about 30 seconds, and a biodegradable polyester sheet with an area of about 10 cm × 10 cm and a thickness of about 300 μm was manufactured.

[0514] Manufacture of Biodegradable Polyester Film After preparing two Teflon sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was placed on one Teflon sheet. After putting about 57 g of the manufactured polyester resin pellets into the stainless steel (SUS) frame (area 12 cm × 12 cm), it was covered with the other Teflon sheet and placed in the center of a hot press (Hot Press, manufacturer: Withrap, model name: 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 detached, and immediately cooled with water at about 20 °C for about 30 seconds, and a biodegradable polyester block with an area of about 10 cm × 10 cm and a thickness of about 2.5 mm was manufactured.

[0515] Manufacture of Biodegradable Polyester Film After drying the biodegradable polyester resin pellets at 80 °C for 5 hours, using a blown film extrusion line (manufacturer: Yujin Engineering), it was melt-extruded at 160 °C to manufacture a biodegradable polyester film with a thickness of 50 μm.

[0516]

Table 1

[0517]

Table 2

[0518]

Table 3

[0519]

Table 4

[0520]

Table 5

[0521]

Table 6

[0522] <Evaluation Example> Evaluation Example 1: Average Particle Size (D50) and Standard Deviation <Average Particle Size (D50) and Standard Deviation of Aromatic Dicarboxylic Acid> 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 using a particle size analyzer Microtrac S3500 (Microtrac Inc) in the particle size distribution (PSD): Use 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.

[0523] The standard deviation means the square root of the variance and can be calculated using software.

[0524] <Particle Size of Nanocellulose> Regarding nanocellulose, the particle size and particle size deviation were measured by the principle of dynamic light scattering (DLS) using a Zetasizer Nano ZS (manufacturer: Malvern) at a temperature of 25 °C and a measurement angle of 175 °. At this time, the peak value derived from the polydispersity index (PdI) in the confidence interval of 0.5 was measured as the particle size.

[0525] 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 carried out.

[0526] Specifically, 5 g of the polyester resins of the examples and comparative examples were placed in 500 mL of deionized water (DI Water), then blocked with a stopper so that the water would not evaporate, and a hydrolysis acceleration test was carried out at 80 °C in a convection (hot air) oven. The humidity environment of the biodegradable polyester sheet is the same as that carried out at 100% RH because it is immersed in water.

[0527] 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.

[0528] Sample pretreatment: Dissolve 0.035 mg of PBAT chip in 1.5 ml of THF Measuring device: e2695 from Waters Injection rate (Flow rate): 1 ml / min in THF Injection volume: 50 μl Column temperature (Column Temp): 40 °C Detector: ELSD Column: Styragel Column HR 5E, HR4, HR2

[0529] Evaluation Example 3: Degree of biodegradability The biodegradable polyester resins produced in the examples and comparative examples were mixed with the following compost, and a biodegradation acceleration test was carried out at a temperature of 60 °C and a humidity of 90%.

[0530] Using the gel permeation chromatography (GPC), the number average molecular weight of the polyester resins in the examples and comparative examples was measured after a certain period of time. The 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 biodegradability degree.

[0531] Compost Manufacturer: Taeheung F&G Product name: Native soil (by-product fertilizer grade 1 compost) Compost composition components: 40 wt% pig manure, 15 wt% chicken manure, 37 wt% large sawdust, 5 wt% zeolite, 3 wt% microbial preparation

[0532] Evaluation Example 4: Nuclear magnetic resonance spectroscopy Approximately 10 mg of samples were prepared from the biodegradable polyester resin compositions of the examples and comparative examples, and the samples were dissolved in CDCl3. Then, the solution was subjected to 1 1H-NMR analysis by a nuclear magnetic resonance (NMR) apparatus (JEOL, JNM-LA3000, 500 MHz, 90° pulse) at room temperature. Then, in the obtained NMR data, the peaks of the terephthalic acid, the adipic acid, and the 1,4-butanediol were integrated.

[0533] Pulse: 90° Repetition time: 4 sec Number of integrations: Measured 8 times Temperature: Room temperature (RT) (25 °C)

[0534] Evaluation Example 5: Shore D hardness The hardness of the polyester block was measured by a Shore hardness measuring instrument (SAUTER (registered trademark) Digital Professional Shore Hardness Tester). Thereafter, the polyester block was cut into a size of about 3 cm × 3 cm and immersed in water at temperatures of about 30 °C, about 50 °C, and about 70 °C for about 0.5 hour, about 1 hour, about 18 hours, and about 24 hours. After that, the moisture of the sample was removed, and immediately the wet hardness was measured by the Shore hardness measuring instrument.

[0535] Evaluation Example 6: Swelling Ratio Polyester sheets with measured initial weight and initial thickness were immersed in acetone and acetonitrile at room temperature respectively. After 2 hours, 18 hours, and 24 hours elapsed, they were taken out from each solvent. Thereafter, the weight and thickness of the polyester sheets with the surface solvent removed were measured. The weight swelling ratio and volume swelling ratio were measured based on the changes in the weight and thickness.

[0536] Evaluation Example 7: Water Contact Angle and Polarity Degree On the surface of the biodegradable polyester sheets manufactured in the examples and comparative examples, the water contact angle and polarity degree were measured under the following conditions.

[0537] Surface tension: Wetting tension test mixture Nos. 40 to 64 Manufacturer: Wako Components: Ethylene glycol, monoethyl ether Surface energy measuring instrument: MSA One-Click SFE (product name) / KRUSS (manufacturer)

[0538] As shown in Tables 7 and 8 below, the biodegradability of the biodegradable polyester sheets manufactured in the examples and comparative examples has been derived.

[0539]

Table 7

[0540]

Table 8

[0541] As described in Tables 9 and 10 below, the degree of hydrolysis has been measured.

[0542]

Table 9

[0543]

Table 10

[0544] As described in Tables 11 and 12 below, 1 the peaks and peak areas by H-NMR have been measured.

[0545]

Table 11

[0546]

Table 12

[0547] As described in Tables 13 to 15 below, the initial hardness and the wet hardness have been measured for each temperature and each immersion time.

[0548]

Table 13

[0549]

Table 14

[0550]

Table 15

[0551] As described in Tables 16 to 19 below, the weight swelling ratio and the volume swelling ratio have been measured according to the solvent and the immersion time.

[0552]

Table 16

[0553]

Table 17

[0554]

Table 18

[0555]

Table 19

[0556] As described in Tables 20 and 21 below, the surface physical properties of the biodegradable resin composition according to the examples have been derived.

[0557]

Table 20

[0558]

Table 21

[0559] As described in Tables 7 to 21 above, the biodegradable resin composition according to the examples may have an appropriate initial degree of hydrolysis and a high late-stage degree of hydrolysis. That is, the biodegradable resin composition according to the examples may have a low initial degree of hydrolysis while having a high final degree of hydrolysis.

[0560] Also, as in Tables 7 to 21 above, it was found that the biodegradable resin composition according to the examples has an appropriate wetting hardness change rate and appropriate surface characteristics.

[0561] Also, as shown in Tables 7 to 21 above, it was found that the biodegradable resin composition according to the examples has appropriately low weight swelling ratio, volume swelling ratio, and surface properties.

Industrial Applicability

[0562] The examples can be used for biodegradable resin compositions, films, and molded articles.

Claims

1. comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, The wet hardness reduction rate is 12% to 25%; The wet hardness reduction rate is measured by the following measurement method. Biodegradable molded products. [Measurement method] The biodegradable molded product was processed into a polyester block having a thickness of 2.5 mm, and the initial hardness of the polyester block and the wet hardness after the polyester block was immersed in water at 30°C for 1 hour were measured. The wet hardness reduction rate was a value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

2. Further comprising a metal salt, The biodegradable molded article according to claim 1.

3. Further comprising an ester polyol diol, The biodegradable molded article according to claim 2.

4. The polyester resin includes a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, The wet hardness reduction rate is 12% to 25%; The wet hardness reduction rate is measured by the following measurement method. A biodegradable polyester resin composition. [Measurement method] The biodegradable polyester composition was dried at a temperature of 80°C, placed in a stainless steel frame, and compressed at a temperature of 210°C and a pressure of 10 MPa for 3 minutes to produce a polyester block having a thickness of 2.5 mm. The initial hardness of the polyester block and the wet hardness after the polyester block was immersed in water at 30°C for 1 hour were measured, and the wet hardness reduction rate was a value obtained by dividing the difference between the initial hardness and the wet hardness by the initial hardness.

5. The initial hardness is 30 to 45 in Shore D hardness, The wet hardness is 25 to 40 Shore D hardness. The biodegradable polyester resin composition according to claim 4.

6. The wet hardness reduction rate is 13% to 22%. The biodegradable polyester resin composition according to claim 4.

7. The nitrogen content is 0.1 ppm to 100 ppm based on the weight of the entire composition; The biodegradable polyester resin composition according to claim 4.

8. The water contact angle of the surface of the polyester block is 65° to 90°. The biodegradable polyester resin composition according to claim 4.

9. The surface polarity of the polyester block is 4 mN / m to 7 mN / m. The biodegradable polyester resin composition according to claim 8.

10. Among the diols, the proportion of the diol that binds between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid is 0.3 to 0.

7. The biodegradable polyester resin composition according to claim 4.

11. Among the diols, the proportion of the diol that binds between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid is 0.2 to 0.

3. The biodegradable polyester resin composition according to claim 10.

12. The degree of hydrolysis after 1 week is 35% to 60%, 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. The biodegradable polyester resin composition according to claim 4. [Measurement method] The degree of hydrolysis after 1 week is the reduction rate of the molecular weight relative to the initial value when the biodegradable polyester resin is placed for 1 week under the 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 molecular weight relative to the initial value when the biodegradable polyester resin is placed for 3 weeks under the high temperature and high humidity conditions of a temperature of 80 ° C and a humidity of 100%.

13. The difference between the wet hardness after immersion in water at 30 ° C for 1 hour and the wet hardness after immersion in water at 30 ° C for 20 hours is 10% or less based on the initial hardness. The biodegradable polyester resin composition according to claim 4.

14. The difference between the wet hardness after immersion in water at 30 ° C for 1 hour and the wet hardness after immersion in water at 70 ° C for 1 hour is 10% or less based on the initial hardness. The biodegradable polyester resin composition according to claim 4.

15. It contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The first weight swelling ratio is 15% or less. The first weight swelling ratio is measured by the following measurement method. Biodegradable polyester resin composition. [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. The initial weight of the polyester sheet and the weight of the polyester sheet after being immersed in acetone at room temperature for 24 hours are measured. The first weight swelling ratio is the value obtained by dividing the difference between the weight after immersion and the initial weight by the initial weight.

16. The first volume swelling ratio is 25% or less, The first volume swelling ratio is measured by the following measurement method, The biodegradable polyester resin composition according to claim 15. [Measurement method] The initial volume of the polyester sheet and the volume of the polyester sheet after being immersed in acetone at room temperature for 24 hours are measured. The first volume swelling ratio is the value obtained by dividing the difference between the volume after immersion and the initial volume by the initial volume.

17. The second weight swelling ratio is 20% or less, The second weight swelling ratio is measured by the following measurement method, The biodegradable polyester resin composition according to claim 15. [Measurement method] The initial weight of the polyester sheet and the weight of the polyester sheet after being immersed in acetonitrile at room temperature for 24 hours are measured. The second weight swelling ratio is the value obtained by dividing the difference between the weight after immersion and the initial weight by the initial weight.

18. The second volume swelling ratio is 25% or less, The second volume swelling ratio is measured by the following measurement method, The biodegradable polyester resin composition according to claim 17. [Measurement method] The initial volume of the polyester sheet and the volume of the polyester sheet after being immersed in acetonitrile at room temperature for 24 hours are measured. The second volume swelling ratio is the value obtained by dividing the difference between the volume after immersion and the initial volume by the initial volume.

19. Further comprising polycaprolactone diol, The biodegradable polyester resin composition according to claim 15.

20. The weight swelling ratio is less than 12%, The biodegradable polyester resin composition according to claim 15.

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