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

Abstract

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

Description

Technical Field

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

Background Art

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

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

[0004] These biodegradable resin compositions are disclosed in Korean Patent Publication No. 2012-0103158, etc.

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0006] The manufacturing method of the biodegradable polyester resin composition according to the embodiment includes a step of subjecting a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid to an esterification reaction to form a prepolymer, a step of subjecting the prepolymer to polycondensation to form a polycondensation composition, and a step of reacting the polycondensation composition and a silicon-based hydrolysis-resistant agent.

[0007] The manufacturing method of the biodegradable polyester resin composition according to an embodiment may further include a step of adding a metal salt.

[0008] In the manufacturing method of the biodegradable polyester resin composition according to an embodiment, the metal salt may contain an iron element.

[0009] In the manufacturing method of the biodegradable polyester resin composition according to an embodiment, the hydrolysis-resistant agent may contain a silane containing two or more functional groups.

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

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

[0012] In the manufacturing method of the biodegradable polyester resin composition according to an embodiment, the acid value may be about 2.0 mgKOH / g or less.

[0013] In a method for producing a biodegradable polyester resin composition according to an embodiment, the degree of hydrolysis after 1 week is about 35% to about 60%, and the degree of hydrolysis after 1 week may be the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester film is placed for about 1 week under high temperature and high humidity conditions of a temperature of about 80 °C and a humidity of about 100%.

[0014] A biodegradable polyester resin composition according to an embodiment includes a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, a metal salt, and a silicon element.

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

[0016] In a biodegradable polyester resin composition according to an embodiment, the degree of hydrolysis after 1 week is about 35% to about 60%, and the degree of hydrolysis after about 3 weeks is about 85% or more. The degree of hydrolysis after 1 week and the degree of hydrolysis after 3 weeks can be measured by the following measurement method.

[0017] [Measurement method] The degree of hydrolysis after 1 week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for about 1 week under high temperature and high humidity conditions of a temperature of about 80 °C and a humidity of about 100%. The degree of hydrolysis after 3 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for about 3 weeks under high temperature and high humidity conditions of a temperature of about 80 °C and a humidity of about 100%.

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

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

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

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

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

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

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

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

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

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

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

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

[0030] The manufacturing method of the biodegradable polyester resin composition according to the embodiment includes a step of reacting a polycondensation composition and a silicon-based hydrolysis-resistant agent. Thereby, the biodegradable polyester resin composition according to the embodiment may have improved hydrolysis resistance. Further, the silicon-based hydrolysis-resistant agent can function as a coupling agent for coupling the polymer resin contained in the polycondensation composition.

[0031] Thereby, the silicon-based hydrolysis-resistant agent can improve the degree of polymerization of the biodegradable polyester resin composition according to the embodiment.

[0032] Therefore, since the biodegradable polyester resin composition according to the embodiment contains the silicon-based hydrolysis-resistant agent, it may have hydrophobic characteristics and may have an appropriate degree of hydrolysis.

[0033] Further, the manufacturing method of the biodegradable polyester resin composition according to the embodiment may further include a step of adding a metal salt. By the metal salt, the biodegradability of the biodegradable polyester resin composition according to the embodiment can be improved. Further, by the metal salt, the degree of late-stage hydrolysis in the biodegradable polyester resin composition according to the embodiment can be improved. That is, the biodegradable polyester resin composition according to the embodiment may have an appropriate metal content and an appropriate silicon element content.

[0034] Thereby, the biodegradable polyester resin composition according to the embodiment may have improved physical properties during the actual use period and may be easily biodegradable after use.

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

[0036] At the same time, since the biodegradable polyester resin composition according to the examples has a high degree of biodegradability, the film produced from the biodegradable polyester resin composition according to the examples may be easily decomposed when discarded after use.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0038] Hereinafter, the invention will be described in detail with reference to specific examples. The specific examples are not limited to the content disclosed below, and can be modified into various forms without changing the gist of the invention.

[0039] In this specification, when a certain part "includes" a component, this means that, unless otherwise stated, it does not exclude other components and may further include other components.

[0040] Also, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification are modified by the term "about" unless otherwise specified.

[0041] Terms such as first, second, primary, and secondary in this specification are used to describe various components, and the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0042] ppm in this specification is a unit based on mass. The ppm is one in one million of the total mass. That is, the ppm is 0.0001 wt% based on the total mass.

[0043] 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.

[0044] 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.

[0045] In the description of the biodegradable polyester resin composition according to the examples, the diol residue may be represented by the diol. In the biodegradable polyester resin, the dicarboxylic acid residue may be represented by the dicarboxylic acid. Also, the residue may be represented by the component.

[0046] 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.

[0047] 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.

[0048] 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.

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

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

[0051] 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.

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

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

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

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

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

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

[0058] The biodegradable polyester resin may contain diol residues derived from 1,4-butanediol in a content of 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.

[0059] 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 59 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 53 mol% based on the total dicarboxylic acid.

[0060] 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 41 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.

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

[0062] 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 bonding to the aliphatic dicarboxylic acid.

[0063] 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 bonding to the aromatic dicarboxylic acid.

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

[0065] The number of the first blocks may be 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.

[0066] The number of the first blocks may vary depending on the content of the aromatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the crosslinking ratio described later. That is, 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, the number of the first blocks may increase.

[0067] 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.

[0068] 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.

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

[0070]

Chemical Formula

[0071] 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 1 to 20.

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

[0073] The second block may be represented by Chemical Formula 2 below.

[0074] [Chemical Formula]

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

[0076] R3 and R4 may be butylene groups.

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

[0078] [Chemical Formula]

[0079] 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 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 1 to 20.

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

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

[0082] Alternatively, the biodegradable polyester resin may include a first block containing residues of 1,4-butanediol or its derivatives and residues of dimethyl terephthalate or its derivatives.

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

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

[0085] The biodegradable polyester resin according to an embodiment of the present invention may include a first block containing residues of 1,4-butanediol or its derivatives and residues of terephthalic acid or its derivatives, and a second block containing residues of 1,4-butanediol or its derivatives and residues of adipic acid or its derivatives.

[0086] The first block may be represented by Chemical Formula 4 below, and the second block may be represented by Chemical Formula 5 below.

[0087]

Chemical Formula

[0088] Here, m may be 1 to 20.

[0089]

Chemical Formula

[0090] Here, n may be 1 to 20.

[0091] The biodegradable polyester resin may be represented by the following Chemical Formula 6.

[0092]

Chemical Formula

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

[0094] When the first block and the second block satisfy the above configuration, it can be more advantageous for providing a biodegradable polyester sheet, film, or molded article excellent in biodegradability and hydrolysis resistance and having improved physical properties.

[0095] Further, when the biodegradable polyester resin contains the first block and the second block within the above range, the biodegradable polyester resin composition according to the examples may have appropriate mechanical properties and appropriate UV resistance properties.

[0096] 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.

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

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

[0099] 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.

[0100] The biodegradable polyester resin may further contain a branching agent. The branching agent may contain at least one or more selected from the group consisting of a trihydric or higher alcohol, an anhydride, or a tricarboxylic acid or higher. The branching agent can react with the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. Thereby, the branching agent may be included as part of the molecular structure in the biodegradable polyester resin.

[0101] At least one or more of the trihydric or higher alcohols may be selected from the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0102] The carboxylic acid having a valence of 3 or more may be at least one selected from the group consisting of methane tricarboxylic acid, ethanetricarboxylic acid, citric acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzenetricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, or benzene-1,2,4,5-tetracarboxylic acid.

[0103] The anhydride may contain at least one 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.

[0104] 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 entire 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 entire 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 entire biodegradable polyester resin.

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

[0106] The biodegradable polyester resin may further contain a polycarbonate diol. The polycarbonate diol may be contained by binding to the molecular structure in the biodegradable polyester resin.

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

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

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

[0110] The OH value of the polycarbonate diol may be from about 20 mgKOH / g to about 350 mgKOH / g. The OH value of the polycarbonate diol may be from about 30 mgKOH / g to about 300 mgKOH / g.

[0111] The polycarbonate diol 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 polycarbonate diol 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 polycarbonate diol 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.

[0112] Since the polycarbonate diol 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 biodegradation.

[0113] The biodegradable polyester resin may further contain a polyether polyol. The polyether polyol may be contained by being bonded to the biodegradable polyester resin in a molecular structure.

[0114] The polyether polyol may be produced by subjecting an initiator having two or more active hydrogens (-OH or NH2) to an addition reaction with propylene oxide (PO) or ethylene oxide (EO). Examples of the polyether polyol include polypropylene glycol, polyethylene glycol, or polytetramethylene glycol.

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

[0116] Also, the viscosity of the polyether polyol may be about 300 cps to about 20000 cps. The viscosity of the polyether polyol may be about 400 cps to about 15000 cps. The viscosity of the polyether polyol may be about 500 cps to about 14000 cps. The viscosity of the polyether polyol can be measured at room temperature according to ASTM / ISO 2555.

[0117] The polyether polyol may be contained in the biodegradable polyester resin at a content 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 polyether polyol may be contained in the biodegradable polyester resin at a content 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 polyether polyol may be contained in the biodegradable polyester resin at a content of about 1 part by weight to about 3 parts by weight based on 100 parts by weight of the biodegradable polyester resin.

[0118] Since the polyether polyol has the 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 biodegradation.

[0119] 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.

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

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

[0122] The nanocellulose may be one or more selected from the group consisting of nanocrystalline cellulose, cellulose nanofiber, microfibrillated cellulose, 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.

[0123] The nanocellulose may contain a metal bound by an ionic bond. The nanocrystalline cellulose may contain a sodium element. Also, the nanocrystalline cellulose may contain a sulphate. The nanocrystalline cellulose may contain a carboxylate. The nanocrystalline cellulose may be cellulose hydrogen sulphate sodium salt.

[0124] The nanocellulose may be represented by Chemical Formula 7 below.

[0125] [Chemical Formula]

[0126] Here, x is from 1 to 35, and y may be from 1 to 10. x is from 15 to 35, and y may be from 1 to 10.

[0127] The nanocellulose is about 200 m 2 / g to about 600 m 2It may have a specific surface area of / g. The nanocellulose has an area of about 250 m 2 / g to about 500 m 2 / g and may also have a specific surface area.

[0128] 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.

[0129] 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%.

[0130] 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.

[0131] The average length of the nanocellulose may be from about 20 nm to about 300 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.

[0132] By satisfying the above ranges for the diameter and length of the nanocellulose, 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.

[0133] The diameter and length of the nanocellulose can be measured by atomic force microscopy in a state of being dispersed in water.

[0134] The sulfur content of the nanocellulose may be about 0.1 wt% to about 1.2 wt% based on the entire nanocrystalline cellulose. The sulfur content of the nanocellulose may be about 0.2 wt% to about 1.1 wt% based on the entire nanocellulose.

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

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

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

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

[0139] Since the nanocellulose has the above characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0140] In addition, the nanocellulose can function as a crystal nucleating agent and 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.

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

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

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

[0144] The biodegradable polyester resin composition according to the examples may contain a metal salt.

[0145] 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.

[0146] The metal salt may be at least one selected from the group consisting of nitrates, sulfates, hydrochlorides, carboxylates, etc. The metal salt may be at least one 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. The metal salt may be at least one selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, sodium nitrate, etc.

[0147] 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).

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

[0149] The biodegradable polyester resin composition according to the examples contains the metal salt in the above content, so the hydrolysis rate and biodegradation rate can be appropriately adjusted.

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

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

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

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

[0154] The hydrolysis-resistant agent may be one that binds to the biodegradable polyester resin. The hydrolysis-resistant agent may be one that chemically binds to the biodegradable polyester resin. The hydrolysis-resistant agent may be one that chemically binds to a polymer contained in the biodegradable polyester resin. The hydrolysis-resistant agent can couple polymers contained in the biodegradable polyester resin to each other.

[0155] Since the biodegradable polyester resin composition according to the examples contains the hydrolysis-resistant agent within the above range, it may have appropriate hydrolysis resistance characteristics. In particular, since the biodegradable polyester resin according to the examples contains the hydrolysis-resistant agent within the above range, it may have appropriate initial hydrolysis characteristics and improved biodegradability.

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

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

[0158] Further, the hydrolysis-resistant agent 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. As a result, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

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

[0160] The chain extender may contain isocyanate.

[0161] The chain extender may be selected from at least one or more of the group consisting of monofunctional isocyanate or polyfunctional isocyanate.

[0162] 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).

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

[0164] 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.

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

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

[0167] 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% based on the total composition. 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% based on the total composition. 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% based on the total composition.

[0168] 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.

[0169] 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.

[0170] Also, the chain extender can couple the polymers contained in the biodegradable polyester resin, and thereby the proportion of high-molecular-weight polymers in the biodegradable polyester resin composition according to the examples can be increased. Thereby, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

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

[0172] The oligomer may be contained in the biodegradable polyester resin composition according to the embodiment 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 embodiment 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 embodiment 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 embodiment at about 7000 ppm to about 15000 ppm based on the entire resin composition.

[0173] 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.

[0174] The oligomer may contain an oligomer in which the molar ratio of the aliphatic dicarboxylic acid is higher than the molar ratio of the aromatic dicarboxylic acid. Among the oligomers, the proportion of the oligomer containing relatively more aliphatic dicarboxylic acid may be even higher than the proportion of the oligomer containing relatively more aromatic dicarboxylic acid.

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

[0176] In addition, the oligomer can appropriately adjust the biodegradability of the biodegradable polyester resin composition according to the examples. The oligomer may be a biodegradability regulator that appropriately adjusts the biodegradability of the biodegradable polyester resin composition according to the examples.

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

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

[0179] In addition, the heat stabilizer may be an antioxidant having a function as an antioxidant.

[0180] 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 the content of the heat stabilizer satisfying the above range, the deterioration of the polymer due to high temperature during the reaction process can be controlled, the end groups of the polymer can be reduced, and the color can be improved. In addition, the heat stabilizer can suppress the activation of a titanium-based catalyst or the like and adjust the reaction rate.

[0181] The biodegradable polyester resin composition according to the embodiment 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.

[0182] The elongation improver may be contained in the biodegradable polyester resin composition according to the embodiment in a content 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 embodiment in a content of about 0.01 part by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0183] The biodegradable polyester resin composition according to the embodiment may contain an inorganic filler. The inorganic filler may be 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.

[0184] Regarding the inorganic filler, based on the volume in the particle size distribution obtained by the laser diffraction method, the cumulative 50% particle size (D50) 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.

[0185] 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 m2 It may be even more than / g.

[0186] The inorganic filler may be included in the biodegradable polyester resin composition according to the examples in an amount of about 3 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.

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

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

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

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

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

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

[0193] Also, the number of terminal carboxyl groups in the biodegradable polyester resin composition according to the examples may be about 50 eq / ton or less. For example, the number of terminal carboxyl groups in the biodegradable polyester resin according to the examples may be about 50 eq / ton or less, about 48 eq / ton or less, about 45 eq / ton or less, or about 42 eq / ton or less. When the number of terminal carboxyl groups is adjusted within the above range and the biodegradable polyester resin composition according to the examples is extruded to form a molded product, deterioration can be prevented and improved mechanical properties can be realized.

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

[0195] The process of manufacturing the biodegradable polyester resin composition according to the examples is as follows.

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

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

[0198] The step of manufacturing the slurry includes the step of mixing and treating the diol and the aromatic dicarboxylic acid. That is, the step of manufacturing the slurry is a pre-treatment step before the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid and slurrying them. At this time, the diol may contain a biomass-based diol component. The temperature of the slurry of the diol and the aromatic dicarboxylic acid may be about 5°C to about 15°C higher than the melting point of the diol. For example, when the diol is 1,4-butanediol, the temperature of the slurry may be about 35°C to about 45°C.

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

[0200] By mixing and pre-treating the diol and the aromatic dicarboxylic acid to form a slurry, not only can the diol and the aromatic dicarboxylic acid react uniformly, but it is also effective in promptly carrying out the esterification reaction rate, so the reaction efficiency can be enhanced.

[0201] In particular, when the aromatic dicarboxylic acid has complete crystallinity and is in powder form like terephthalic acid, its solubility in the diol is very low, and a homogeneous reaction may not easily occur. Therefore, the pre-treatment process of forming the slurry can play a very important role in providing a biodegradable polyester resin, sheet, film, and molded article having excellent physical properties according to embodiments of the present invention and enhancing the reaction efficiency.

[0202] 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, and has a very low solubility in the diol. Therefore, when a pre-treatment process is performed before the esterification reaction, it can react with the diol within the solid matrix of terephthalic acid to increase the surface area and induce a uniform reaction.

[0203] Also, when the aromatic dicarboxylic acid is dimethyl terephthalic acid, the pre-treatment process can make the dimethyl terephthalic acid in a molten state at about 142°C to 170°C and react it with the diol, so that the esterification reaction rate can be made faster and more efficiently.

[0204] On the other hand, in the pre-treatment stage of manufacturing the slurry, the structure and physical properties of the biodegradable polyester resin may vary depending on the particle size, particle size distribution, pre-treatment reaction conditions, etc. of the aromatic dicarboxylic acid.

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

[0206] In the pretreatment step, the diol and the aromatic dicarboxylic acid can be mixed and charged into the slurry stirrer 100 (tank).

[0207] For example, the slurry stirrer 100 may be such that the lowermost part is of an anchor type, the height to the agitator is 20 mm or more, and it is more advantageous for achieving an efficient stirring effect to be provided with two or more rotating blades.

[0208] For example, the slurry stirrer 100 may have a height to the agitator of 20 mm or more, that is, there may be almost a connection between the reactor and the lowermost part of the agitator. In this case, a slurry can be obtained without precipitation. If the pattern, form, and rotating blades of the agitator do not satisfy the above conditions, when the diol and the aromatic dicarboxylic acid are initially mixed, the aromatic dicarboxylic acid may settle to the bottom, and in this case, phase separation may occur.

[0209] The pretreatment step of manufacturing the first 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 or for 10 minutes to 200 minutes.

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

[0211] 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.

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

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

[0214] When the diol is charged in an amount even more than the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be easily dispersed.

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

[0216] The method for manufacturing the biodegradable polyester resin mixes a diol and an aromatic dicarboxylic acid, performs an esterification reaction using the slurry obtained by pretreatment to obtain a prepolymer, and performs a polycondensation reaction on the prepolymer, thereby efficiently achieving the structure and physical properties of the biodegradable polyester resin targeted by the embodiments of the present invention.

[0217] The method for producing the biodegradable polyester resin includes a step of subjecting the slurry and the aliphatic dicarboxylic acid to an esterification reaction to produce a prepolymer. The slurry and the aliphatic dicarboxylic acid can react in the ester reaction section.

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

[0219] The esterification reaction can be carried out at least twice or more. A prepolymer to be introduced into the polycondensation step can be formed by the esterification reaction.

[0220] In one embodiment, the esterification reaction can be carried out once after introducing an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid into the slurry. That is, after the slurry is introduced into the esterification reactor, 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.

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

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

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

[0224] 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.

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

[0226] 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 under normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the esterification reaction can be carried out for 0.5 hour to 5.5 hours, 0.5 hour to 4.5 hours or 1 hour to 4 hours, but is not limited thereto.

[0227] In one embodiment, the polycarbonate diol and / or the polyether polyol can be mixed with the slurry to carry out a first esterification reaction. In contrast, the polycarbonate diol and / or the polyether polyol can be charged into a second esterification reaction.

[0228] Also, after the first ester reaction, a mixture of the aliphatic dicarboxylic acid and the diol can be charged into the esterification reaction section to carry out a second ester reaction together with the first ester reaction product. Also, the polycarbonate diol and / or the polyether polyol can be charged into the second esterification reaction.

[0229] The first esterification 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.

[0230] The second esterification 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.

[0231] 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 can be adjusted respectively, and the ratio of the number of the first block and the second block can be adjusted. Also, 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.

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

[0233] The prepolymer can be formed by the esterification reaction.

[0234] 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.

[0235] 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).

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

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

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

[0239] 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 by ultrasonic waves in the form of water-dispersed nanocellulose.

[0240] First, the bead mill pretreatment can be performed using a vertical mill or a horizontal mill as a wet milling device. Although the horizontal mill is preferable in that it can hold a larger amount of beads inside the chamber, reduces mechanical uneven wear, reduces bead wear, and is easy to maintain, it is not limited thereto.

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

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

[0243] By having the diameter of the beads satisfy the above range, the dispersibility of nanocellulose can be further improved. When the diameter of the beads exceeds the above range, the average particle size and particle size deviation of nanocellulose may increase, resulting in lower dispersibility.

[0244] Also, for the bead mill pretreatment, it is preferable to use beads with a higher specific gravity than that of nanocellulose in terms of being able to transmit sufficient energy. For example, the beads may be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide, which have a higher specific gravity than the water-dispersed nanocellulose. Among them, zirconium beads with a specific gravity 4 times or more higher than that of the water-dispersed nanocellulose are preferable, but not limited thereto.

[0245] Also, the ultrasonic pretreatment is a method of physically closing or pulverizing nanoparticles by the waves generated by emitting ultrasonic waves of 20 kHz into the solution.

[0246] The ultrasonic pretreatment can be carried out at an output of 30000 J / s or less for a time of less than 30 minutes. For example, the ultrasonic pretreatment can be carried out 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 having the output and the implementation time satisfy the above range, the effect of the ultrasonic pretreatment, that is, the improvement of dispersibility, can be maximized. When the output exceeds the above range, on the contrary, the nanoparticles may re-aggregate, resulting in lower dispersibility.

[0247] 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.

[0248] Since the nanocellulose contains ionically bonded metal, its dispersibility in water is very high. Further, a highly dispersed aqueous dispersion of the nanocellulose can be obtained by the bead mill pretreatment and / or the ultrasonic pretreatment. The content of the nanocellulose in the nanocellulose aqueous dispersion may be about 1 wt% to about 50 wt%.

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

[0250] 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.

[0251] The biodegradable polyester resin may contain at least one titanium-based catalyst 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 at least one germanium-based catalyst selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethylgermanium, tetraethylgermanium, and germanium sulfide.

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

[0253] Further, the heat stabilizer may be introduced together with the slurry before the esterification reaction. The heat stabilizer may be introduced into the esterification reaction unit 200 during the esterification reaction. The heat stabilizer may be introduced into the ester reaction product after the esterification reaction. Further, the heat stabilizer may be introduced together with the aliphatic dicarboxylic acid. Further, the heat stabilizer may be introduced into the esterification reaction unit 200 after the first ester reaction and before the second ester reaction.

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

[0255] The content of the heat stabilizer may be 3,000 ppm or less based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Specifically, the content of the heat stabilizer may be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By the content of the heat stabilizer satisfying the above range, the deterioration of the polymer due to high temperature during the reaction process can be controlled, the end groups of the polymer can be reduced, and the color can be improved.

[0256] 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 can be uniformly dispersed in the biodegradable polyester resin.

[0257] 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.

[0258] Also, the first recovery section 510 recovers reaction by-products such as water from the esterification reaction section 200. The first recovery section 510 can recover the by-products generated in the esterification reaction by applying a vacuum pressure to the esterification reaction section 200 or performing reflux.

[0259] 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.

[0260] 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.

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

[0262] Also, the polycondensation reaction may include a primary polycondensation and a secondary polycondensation.

[0263] 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 can be carried out 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.

[0264] 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 can be carried out 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.

[0265] Also, before the polycondensation reaction, a titanium-based catalyst or a germanium-based catalyst may be further added to the prepolymer. Also, 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.

[0266] 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 the number average molecular weight of the polymer satisfying the above range, physical properties, impact resistance, durability, and moldability can be further improved.

[0267] Also, 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.

[0268] 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.

[0269] Thereafter, the hydrolysis-resistant agent and / or the chain extender are added to the polymer. Thereafter, the polymer, the hydrolysis-resistant agent, and the chain extender are uniformly mixed and maintained at a temperature of about 200°C to about 260°C for about 1 minute to about 15 minutes. As a result, the polymer comes to react with the hydrolysis-resistant agent and / or the chain extender.

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

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

[0272] Thereby, the biodegradable polyester resin composition according to the example may have an appropriate degree of hydrolysis and a high degree of biodegradability.

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

[0274] 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.

[0275] 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.

[0276] The pellets can undergo further post-treatment steps. The pellets can be introduced into the post-treatment section 400 to perform the post-treatment steps.

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

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

[0279] 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.

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

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

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

[0283] After the pellets are manufactured, the biodegradable polyester resin can be compounded with the two biodegradable resins. Further, at least one or more 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.

[0284] The compounding step may be as follows.

[0285] 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 fed into an extruder. The mixed biodegradable polyester resin composition melts at a temperature of about 120°C to about 260°C in the extruder and mixes with each other. Then, the melt-mixed biodegradable polyester resin composition is extruded, cooled, cut, and re-pelletized. Through such a process, it is possible to produce a biodegradable polyester resin composition according to an example by compounding with the two biodegradable resins.

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

[0287] A biodegradable polyester film can be produced from the biodegradable polyester resin according to the example.

[0288] 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.

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

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

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

[0292] In the step of drying and melt-extruding the biodegradable resin composition, the drying can be 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.

[0293] 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.

[0294] Also, the film manufacturing process may be a calendaring process.

[0295] Biodegradable polyester molded product A biodegradable polyester molded product can be manufactured using the biodegradable polyester resin.

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

[0297] 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, garbage bags by weight, 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, the molded article may be in the form of a disposable container used for food packaging containers such as lunch boxes. Also, the molded article may be molded articles in various forms such as disposable straws, spoons, eating plates, forks, etc.

[0298] In particular, since the molded article can be formed of the biodegradable polyester resin that can improve not only physical properties such as impact absorption energy and hardness, but particularly impact resistance and durability, it can exhibit excellent properties when applied to packaging materials for products stored and transported at low temperatures, interior automotive materials that require durability, garbage bags, mulching films, and disposable products.

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

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

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

[0302] [Formula 1] JPEG2025517981000009.jpg14151

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

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

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

[0306] Also, the manufacturer of the compost may be Taeheung F&G, and the product name of the compost may be native soil (by-product fertilizer grade 1 compost).

[0307] Also, when the reduction rate of the molecular weight 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 3 cm × 3 cm to produce flakes. The flakes are mixed with the compost, and the biodegradation acceleration test is performed.

[0308] The biodegradable polyester film according to the example may have a reduction rate of the molecular weight as described above. Similarly, the biodegradable polyester film according to the example can be cut into a size of about 3 cm × 3 cm to produce flakes. The flakes can be mixed with the compost to perform the biodegradation acceleration test.

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

[0310] [Formula 2] JPEG2025517981000010.jpg13151

[0311] The biodegradability of the biodegradable polyester resin composition according to the examples can be measured based on the amount of carbon dioxide generated in accordance with KS M3100-1. Specifically, a seeding source container containing only the compost produced in a compost plant is prepared, and a test container is prepared in which 5% by weight of the flakes of the biodegradable polyester resin composition are added to the compost based on the dry weight of the compost. Thereafter, the compost and the flakes are cultured for 180 days under the conditions of a temperature of 58 ± 2°C, a water content of 50%, and an oxygen concentration of 6% or more. The carbon dioxide generated in each container is collected, and the amount of carbon dioxide generated in each container is measured by titration of an aqueous phenolphthalein solution. As shown in the above formula 2, the biodegradability is derived from the ratio of the carbon dioxide generated by the biodegradable polyester resin composition to the theoretically generated amount of carbon dioxide.

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

[0313] The biodegradable polyester film according to the examples may have the biodegradability as described above. Similarly, the biodegradable polyester film according to the examples is cut into a size of about 3 cm × 3 cm to produce flakes. The flakes can be mixed with the compost to perform the biodegradation test.

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

[0315] In order to measure the degree of hydrolysis, the biodegradable resin composition according to the examples is immersed in water at 80°C (100% RH), and then a hydrolysis acceleration test is performed. After a certain period of time has elapsed, 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.

[0316] The degree of hydrolysis may be represented by the following Mathematical Formula 3.

[0317] [Mathematical Formula 3] JPEG2025517981000011.jpg14148

[0318] Here, the biodegradable polyester resin composition according to the example is immersed in water at 80°C and then undergoes a hydrolysis acceleration test for a certain period. Before the hydrolysis acceleration test is performed, 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).

[0319] 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.

[0320] Also, when the degree of hydrolysis is measured, the biodegradable polyester resin composition according to the example is produced into a sheet having a thickness of about 300 μm. Thereafter, the produced sheet is cut into a size of about 3 cm × 3 cm to produce flakes. The flakes can be immersed in the warm water to perform the hydrolysis acceleration test.

[0321] In the biodegradable polyester resin composition according to the example, the degree of hydrolysis after 1 week may be about 40% to about 65%. In the biodegradable polyester resin composition according to the example, the degree of hydrolysis after 1 week may be about 45% to about 63%.

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

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

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

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

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

[0327] The biodegradable polyester resin composition according to the example 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 time.

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

[0329] [Formula 4] JPEG2025517981000012.jpg15128

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

[0331] The wet hardness reduction rate after immersion at the temperature of 30°C for 24 hours 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 24 hours, the wet hardness of the polyester block is immediately measured. Then, the wet hardness reduction rate after immersion at the temperature of 30°C for 24 hours can be derived by the following Equation 4.

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

[0333] 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.

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

[0335] The reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 16% or less. The reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 15% or less. The reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 14% or less. The reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 13% or less. The reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 12% or less. The minimum value of the reduction rate of wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 1%, about 3%, about 5%, or about 6%.

[0336] The wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 28 to about 43 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 29 to about 41 in Shore D hardness. The wet hardness after immersion at the temperature of 30°C for 0.5 hour may be about 30 to about 39 in Shore D hardness.

[0337] The deviation of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a temperature of 30°C for 0.5 hours may be about 10% or less. The deviation of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a 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 a temperature of 30°C for 24 hours and the wet hardness after immersion at a temperature of 30°C for 0.5 hours by the initial hardness. The deviation of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a temperature of 30°C for 0.5 hours may be about 7% or less. The deviation of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a temperature of 30°C for 0.5 hours may be about 5% or less.

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

[0339] The wet hardness after immersion at a temperature of 30°C for 1 hour may be about 28 to about 43 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 1 hour may be about 29 to about 41 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 1 hour may be about 30 to about 39 in Shore D hardness.

[0340] The deviation of 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 of 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 of 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.

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

[0342] The wet hardness after immersion at a temperature of 30°C for 18 hours may be about 28 to about 43 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 18 hours may be about 29 to about 41 in Shore D hardness. The wet hardness after immersion at a temperature of 30°C for 18 hours may be about 30 to about 39 in Shore D hardness.

[0343] The deviation of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours 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 of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours 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 of the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a temperature of 30°C for 18 hours may be about 5% or less.

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

[0345] The wet hardness after immersion at a temperature of about 50°C for 24 hours may be about 28 to about 43 in Shore D hardness. The wet hardness after immersion at a temperature of about 50°C for 24 hours may be about 29 to about 41 in Shore D hardness. The wet hardness after immersion at a temperature of about 50°C for 24 hours may be about 30 to about 39 in Shore D hardness.

[0346] The deviation between the wet hardness reduction rate after immersion at a temperature of 30°C for 24 hours and the wet hardness reduction rate after immersion at a temperature of 50°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 24 hours and the wet hardness reduction rate after immersion at a temperature of 50°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 24 hours and the wet hardness reduction rate after immersion at a temperature of 50°C for 24 hours may be about 5% or less.

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

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

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

[0350] Also, the acid value of the biodegradable polyester resin composition according to the examples may be about 0.01 mgKOH / g to about 3 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be about 0.1 mgKOH / g to about 2.8 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be about 0.1 mgKOH / g to about 2.5 mgKOH / g.

[0351] Since the biodegradable polyester resin composition according to the examples has an acid value within the above range, it may have hydrolysis degree characteristics and biodegradability characteristics as described above.

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

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

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

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

[0356] Since the biodegradable polyester resin composition according to the example contains silicon element and iron element within the above ranges, it may have an appropriate degree of hydrolysis and an appropriate degree of biodegradability. In particular, the degree of hydrolysis can be appropriately adjusted according to the content of the silicon element, and the degree of biodegradability can be appropriately adjusted according to the content of the iron element.

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

[0358] In the biodegradable polyester resin composition according to the example, the rate of decrease in wet hardness is 15% or less. Thus, the biodegradable polyester resin composition according to the example may have high moisture resistance. The biodegradable polyester resin composition according to the example can maintain high mechanical properties even when exposed to water or in a high-humidity environment.

[0359] Thus, when the biodegradable polyester resin composition according to the example is used for packaging foods with a high water content, etc., mechanical property deviations can be minimized.

[0360] Also, the biodegradable polyester resin composition according to the example may have hydrophobic properties. Thus, the biodegradable polyester resin composition according to the example can absorb less moisture in the air. Thus, the biodegradable polyester resin composition according to the example may have improved storage stability.

[0361] The biodegradable polyester resin composition according to the example may contain a silicone-based hydrolysis-resistant agent. Thus, the biodegradable polyester resin composition according to the example may have improved hydrolysis resistance. Also, the silicone-based hydrolysis-resistant agent can function as a coupling agent for coupling the polymer resin contained in the polycondensation composition.

[0362] Thus, the silicone-based hydrolysis-resistant agent can improve the degree of polymerization of the biodegradable polyester resin composition according to the example.

[0363] Thus, the biodegradable polyester resin composition according to the example may have improved physical properties during the actual use period and be easily biodegradable after use.

[0364] The biodegradable polyester resin composition according to the examples can be efficiently applied to packaging films and the like. That is, the film produced from the biodegradable polyester resin composition according to the examples is used for normal applications such as packaging. At this time, the biodegradable polyester resin composition according to the examples may initially have a low degree of hydrolysis, and within the normal usage period of the user, the biodegradable polyester film can maintain mechanical and chemical physical properties to a certain extent or more.

[0365] At the same time, since the biodegradable polyester resin composition according to the examples has a high degree of biodegradability, the film produced from the biodegradable polyester resin composition according to the examples may be easily decomposed when discarded after use.

[0366] 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.

[0367] <Production Example> Production of Pretreated Nanocellulose Dry powder cellulose nanocrystals (NVC-100, manufacturer: Celluforce) having a particle size of about 1 μm to about 50 μm were dispersed in water at 1% by weight, and then ultrasonic treatment was performed for 2 minutes at an output of 20,000 J / s using a tip-type ultrasonic disperser to produce pretreated nanocellulose.

[0368] Hydrolysis-resistant agent: 3-glycidoxypropylmethyldiethoxysilane Metal salt: iron nitrate

[0369] <Example> Example 1 Production of biodegradable polyester resin First stage: The stage of obtaining a slurry by pretreatment As shown in Table 1, the pre-treated nanocellulose, iron nitride, 1,4-butanediol (1,4-BDO), and terephthalic acid (TPA) were mixed at a molar ratio of 1.4:1 (1,4-BDO:TPA) and charged into a slurry tank (the bottom of the slurry tank is of the anchor type, with a height to the agitator of 40 mm and equipped with three rotating blades) in a catalyst-free state. At this time, the D50 of the terephthalic acid (TPA) was 130 μm.

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

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

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

[0373] Stage 3: Performing a polycondensation reaction Based on the total weight of the prepolymer, 5 wt% of the produced oligomer, 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 and 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 55,000 g / mol.

[0374] Thereafter, based on the polymer, about 600 ppm of epoxy glycidyl silane was added to the polymer. Then, the terminal group extension reaction of the polymer was carried out at a temperature of about 240°C for about 10 minutes. Then, after cooling this to 5°C, it was cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0375] Examples 2 to 5 and Comparative Examples 1 and 2 As shown in Table 1 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, and hydrolysis-resistant agent are different. Except for the said content and the said process, other processes were carried out substantially referring to Example 1.

[0376] Production of Biodegradable Polyester Sheet After preparing two Teflon (registered trademark) sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was placed on one Teflon (registered trademark) sheet, and about 7 g of the produced polyester resin pellets were put into the stainless steel (SUS) frame (area 12 cm × 12 cm). Then, it was covered with the other Teflon (registered trademark) sheet and placed in the center of a hot press (manufacturer: Wisrap, model: WL1600SA) having a surface size of about 25 cm × 25 cm. This was maintained at about 210°C under a pressure of about 10 Mpa for about 3 minutes, then removed, and immediately cooled with water at about 20°C for about 30 seconds to produce a biodegradable polyester sheet having an area of about 10 cm × 10 cm and a thickness of about 300 μm.

[0377] Production of Biodegradable Polyester Film After drying the biodegradable polyester resin pellets at 80 °C for 5 hours, they were melt-extruded at 160 °C using a blown film extrusion machine (Blown Film Extrusion Line, manufacturer: Yujin Engineering) to produce a biodegradable polyester film with a thickness of 50 μm.

[0378]

Table 1

[0379] Evaluation Example 1: Average particle size (D50) and standard deviation <Average particle size (D50) and standard deviation of aromatic dicarboxylic acid> Using a particle size analyzer Microtrac S3500 (Microtrac Inc) in the particle size distribution (PSD) under the following conditions, the average particle size (D50) and standard deviation (SD, Standard Deviation) of the aromatic dicarboxylic acid (TPA or DMT) were determined:

[0380] 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.

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

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

[0383] Evaluation Example 2: Degree of hydrolysis The biodegradable polyester resins produced in the examples and comparative examples were immersed in water (100% RH) at 80 °C, and then a hydrolysis degree acceleration test was carried out.

[0384] Specifically, 5 g of the polyester resins of the examples and comparative examples were put into 500 mL of deionized water (DI Water), then blocked with a stopper so that the water did 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 when immersed in water, which is carried out at 100% RH.

[0385] 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 hydrolysis degree.

[0386] 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

[0387] Evaluation Example 3: Hydrolysis degree 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%.

[0388] Using the 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 biodegradation degree.

[0389] Compost Manufacturer: Taeheung F&G Product Name: Native Soil (By-Product Fertilizer Grade 1 Compost) Compost Composition: 40 wt% pig manure, 15 wt% chicken manure, 37 wt% large sawdust, 5 wt% zeolite, 3 wt% microbial agent

[0390] Evaluation Example 3: Acid Value KOH and ethyl alcohol were mixed to produce a 0.02 N KOH solution. Then, about 1 g of the biodegradable resin composition according to the examples and comparative examples was dissolved in chloroform. Then, based on the phenolphthalein reagent, the biodegradable resin composition solution was titrated with the KOH solution, and the acid value was measured.

[0391] Acid Value Measuring Equipment: Mettler toledo Titrator Excellence T5

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

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

[0394] As described in Table 3 below, the biodegradability was measured.

[0395]

Table 3

[0396] As described in Table 4 below, the degree of hydrolysis was measured.

[0397]

Table 4

[0398] As described in Table 5 below, the biodegradability per aliphatic dicarboxylic acid was derived.

[0399]

Table 5

[0400] As shown in Table 6 below, the contents of iron element and silicon element were measured.

[0401]

Table 6

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

Industrial Applicability

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

Claims

1. esterifying a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid to form a prepolymer; polycondensing the prepolymer to form a polycondensation composition; reacting the polycondensation composition with a silicon-based hydrolysis-resistant agent; comprising: A method for producing a biodegradable polyester resin composition.

2. further comprising adding a metal salt; The method for producing a biodegradable polyester resin composition according to Claim 1.

3. The metal salt contains iron element; The method for producing a biodegradable polyester resin composition according to Claim 2.

4. The hydrolysis-resistant agent contains a silane having two or more functional groups; The method for producing a biodegradable polyester resin composition according to Claim 1.

5. The hydrolysis-resistant agent contains an epoxy group or an alkoxy group; The method for producing a biodegradable polyester resin composition according to Claim 4.

6. The step of reacting the polycondensation composition with the silicon-based hydrolysis-resistant agent: comprises reacting the polycondensation composition with the silicon-based hydrolysis-resistant agent at a temperature of about 180°C to about 260°C for 5 minutes to 60 minutes; The method for producing a biodegradable polyester resin composition according to Claim 1.

7. having an acid value of about 2.0 mgKOH / g or less; The method for producing a biodegradable polyester resin composition according to Claim 1.

8. having a hydrolysis degree after one week of about 35% to about 60%; The hydrolysis degree after one week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester film is placed for about one week under high temperature and high humidity conditions of a temperature of about 80°C and a humidity of about 100%; The method for producing a biodegradable polyester resin composition according to Claim 1.

9. a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; a metal salt; a silicon element; comprising: A biodegradable polyester resin composition.

10. The metal salt contains iron element; The mass ratio of the iron element to the silicon element is about 0.1 to about 0.7; The biodegradable polyester resin composition according to Claim 9.

11. having a hydrolysis degree after one week of about 35% to about 60%; having a hydrolysis degree after about three weeks of about 85% or more; The hydrolysis degree after one week and the hydrolysis degree after three weeks are measured by the following measurement method; The biodegradable polyester resin composition according to Claim 10. [Measurement method] The degree of hydrolysis after one week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for about one week under high temperature and high humidity conditions of a temperature of about 80°C and a humidity of about 100%. The degree of hydrolysis after three weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for about three weeks under high temperature and high humidity conditions of a temperature of about 80°C and a humidity of about 100%.

12. The content of the iron element is from about 1 ppm to about 100 ppm, The content of the silicon element is from about 1 ppm to about 150 ppm, The biodegradable polyester resin composition according to claim 10.

13. Further comprising nanocellulose, The nanocellulose contains sulfur, The biodegradable polyester resin composition according to claim 12.

14. The wet hardness reduction rate is about 15% or less, The wet hardness reduction rate is measured by the following measurement method, The biodegradable polyester resin composition according to claim 12. [Measurement method] The biodegradable polyester resin composition is processed to produce a polyester block having a thickness of about 2.5 mm. The initial hardness of the polyester block and the wet hardness after the polyester block is immersed in water at about 30°C for about 24 hours are measured. The wet hardness reduction rate is the value obtained by dividing the difference between the wet hardness and the initial hardness by the initial hardness.

15. A polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, A metal salt, A silicon element, Containing, A biodegradable polyester molded article.

16. The metal salt contains an iron element, The mass ratio of the iron element to the silicon element is from about 0.1 to about 0.7, The biodegradable polyester molded article according to claim 15.

17. The degree of hydrolysis after one week is from about 35% to about 60%, The degree of hydrolysis after about three weeks is about 85% or more, The degree of hydrolysis after one week and the degree of hydrolysis after three weeks are measured by the following measurement method, The biodegradable polyester molded article according to claim 16. [Measurement method] The degree of hydrolysis after one week is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for about one week under high temperature and high humidity conditions of a temperature of about 80°C and a humidity of about 100%. The degree of hydrolysis after 3 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition with respect to the initial value when the biodegradable polyester resin composition is placed for about 3 weeks under high temperature and high humidity conditions of a temperature of about 80°C and a humidity of about 100%.

18. The content of the iron element is from about 1 ppm to about 100 ppm, The content of the silicon element is from about 1 ppm to about 150 ppm, The biodegradable polyester molded article according to claim 16.

19. Further comprising nanocellulose, The nanocellulose contains sulfur, The biodegradable polyester molded article according to claim 18.

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

Images