Biodegradable molded article and biodegradable polyester resin composition

Abstract

The example includes a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and has a biodegradability per degree of hydrolysis of 1.35 or more. The biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week. The biodegradability after 9 weeks and the degree of hydrolysis after 1 week disclose a biodegradable molded article measured by the following measurement method.

Description

Technical Field

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

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 demanded. Specifically, polymer materials are inexpensive and have excellent properties such as processability, and are widely used in manufacturing various products such as films, fibers, packaging materials, bottles, and containers. However, when the life of the used products ends, harmful substances are emitted during incineration, and it takes hundreds of years depending on the type to be completely decomposed naturally, which has the disadvantage.

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

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

Summary of the Invention

Problems to be Solved by the Invention

[0005] The examples aim to provide biodegradable molded articles, biodegradable polyester resin compositions, and biodegradable polyester films having appropriate hydrolysis resistance and high biodegradability.

Means for Solving the Problems

[0006] The biodegradable molded article according to the example contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, has a biodegradability of 1.4 or more per degree of hydrolysis, and the biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week. The biodegradability after 9 weeks and the degree of hydrolysis after 1 week are measured by the following measurement method.

[0007] [Measurement method] The biodegradability after 9 weeks is the rate of decrease in molecular weight with respect to the initial state of the biodegradable molded article when the biodegradable molded article is processed into flakes having a thickness of 300 μm and a size of 30 mm × 30 mm and placed under composting conditions at a temperature of 60 °C and a humidity of 90% for 63 days. The degree of hydrolysis after 1 week is the rate of decrease in molecular weight with respect to the initial state of the biodegradable molded article when the flakes are placed under conditions of a temperature of 80 °C and a humidity of 100% for 7 days.

[0008] The biodegradable molded article according to one example contains nanocellulose containing a metal, having an average diameter of 0.5 nm to 10 nm and an average length of 20 nm to 300 nm.

[0009] The biodegradable molded article according to one example further contains a metal salt and a silicon element, and the ratio of the mass of the metal element contained in the metal salt to the silicon element is 0.1 to 0.7.

[0010] The polyester resin composition according to the example contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, has a biodegradability of 1.35 or more per degree of hydrolysis, and the biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week. The biodegradability after 9 weeks and the degree of hydrolysis after 1 week are measured by the following measurement method.

[0011] [Measurement method] The biodegradability after 9 weeks is the reduction rate of the molecular weight of the polyester resin relative to its initial value when the biodegradable polyester resin composition is processed into flakes with a thickness of 300 μm and a size of 30 mm × 30 mm and placed under composting conditions at a temperature of 60 °C and a humidity of 90% for 63 days. The degree of hydrolysis after 1 week is the reduction rate of the molecular weight of the polyester resin relative to its initial value when the flakes are placed under conditions of a temperature of 80 °C and a humidity of 100% for 7 days.

[0012] In the biodegradable resin composition according to one embodiment, the biodegradability after 9 weeks may be 75% or more, and the degree of hydrolysis after 1 week may be 60%.

[0013] In the biodegradable polyester resin composition according to one embodiment, the biodegradability after 1 week may be 45% to 75%, and the biodegradability after 1 week may be the reduction rate of the molecular weight of the flakes relative to their initial value when the flakes are placed under composting conditions at a temperature of 60 °C and a humidity of 90% for 7 days.

[0014] In the biodegradable polyester resin composition according to one embodiment, the degree of hydrolysis after 9 weeks may be 80% or more, and the degree of hydrolysis after 9 weeks may be the reduction rate of the molecular weight of the flakes relative to their initial value when the flakes are placed under conditions of a temperature of 80 °C and a humidity of 100% for 63 days.

[0015] In the biodegradable polyester resin composition according to one embodiment, the acid value may be 2.0 mgKOH / g or less.

[0016] In the biodegradable polyester resin composition according to one embodiment, the increase rate of the biodegradability from 1 week to 4 weeks may be 3.5% / week to 8% / week.

[0017] In the biodegradable polyester resin composition according to one embodiment, the increase rate of the degree of hydrolysis from 1 week to 2 weeks may be 29% / week to 50%, and the increase rate of the degree of hydrolysis from 3 weeks to 6 weeks may be 0.01% / week to 3% / week.

[0018] In the biodegradable polyester resin composition according to one embodiment, the rate of increase in the degree of hydrolysis from 2 weeks to 3 weeks may be 3% / week to 10% / week.

[0019] The biodegradable polyester resin composition according to one embodiment contains a metal salt and a silicon element, and the mass ratio of the metal element contained in the metal salt to the silicon element may be 0.1 to 0.7.

[0020] The biodegradable polyester resin composition according to another embodiment contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and the degree of biodegradation per aliphatic carboxylic acid is 1.7 or more. The degree of biodegradation per aliphatic carboxylic acid is a value obtained by dividing the degree of biodegradation after 9 weeks by the ratio of the aliphatic dicarboxylic acid in the total dicarboxylic acids. The degree of biodegradation after 9 weeks is 85% or more, and the degree of biodegradation after 9 weeks is measured by the following measurement method.

[0021] [Measurement method] The degree of biodegradation after 9 weeks is the rate of decrease in the molecular weight of the polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed under composting conditions, at a temperature of 60°C and a humidity of 90% for 9 weeks.

[0022] In the biodegradable polyester resin composition according to one embodiment, the degree of biodegradation after 9 weeks may be 88% or more.

[0023] In the biodegradable polyester resin composition according to one embodiment, the degree of biodegradation after 1 week is 45% to 65%, and the degree of biodegradation after 1 week may be the rate of decrease in the molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed under composting conditions, at a temperature of 60°C and a humidity of 90% for 1 week.

[0024] In a biodegradable polyester resin composition according to an embodiment, the biodegradability after 2 weeks is 55% to 70%, and the biodegradability after 2 weeks may be the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for 2 weeks under composting conditions, a temperature of 60 °C, and a humidity of 90%.

[0025] In a biodegradable polyester resin composition according to an embodiment, the increase rate of biodegradability from 1 week to 2 weeks may be about 4% / week to about 15% / week.

[0026] In a biodegradable polyester resin composition according to an embodiment, the biodegradability after 4 weeks is 73% to 85%, and the biodegradability after 4 weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to the initial value when the biodegradable polyester resin composition is placed for 4 weeks under high temperature and high humidity conditions of a temperature of 80 °C and a humidity of 100%, and the increase rate of biodegradability from 1 week to 4 weeks may be 3.5% / week to 8% / week.

[0027] In a biodegradable polyester resin composition according to an embodiment, the degree of hydrolysis after 1 week is 35% to 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 relative to the initial value when the biodegradable polyester film is placed for 1 week under high temperature and high humidity conditions of a temperature of 80 °C and a humidity of 100%.

[0028] In a biodegradable polyester resin composition according to an embodiment, it may contain a nitrogen element.

Advantages of the Invention

[0029] The biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples may have a biodegradability of 1.35 or more per degree of hydrolysis. As a result, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples may have a high biodegradability while having an appropriately low degree of hydrolysis. In particular, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples may have a high biodegradability in the later stage while having a low initial degree of hydrolysis.

[0030] In addition, the biodegradable polyester resin composition according to the examples can be efficiently applied to packaging films and the like. The biodegradable molded article and biodegradable film according to the examples can be used for ordinary purposes such as packaging.

[0031] The biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples have a low degree of hydrolysis initially, so they can maintain a certain degree or more of mechanical and chemical physical properties within the normal usage period of the user.

[0032] In addition, the biodegradable molded article, biodegradable polyester resin composition, and biodegradable film according to the examples have a high biodegradability per degree of hydrolysis, so they can be easily decomposed when discarded after use.

[0033] In addition, the biodegradable polyester resin composition according to the examples has a biodegradability of 1.6 or more per aliphatic carboxylic acid. That is, the biodegradable polyester resin composition according to the examples has a low content of aliphatic carboxylic acid and a high biodegradability.

[0034] As a result, the biodegradable polyester resin composition according to the examples may have a high hydrolysis resistance and a high biodegradability because it has a relatively high content of aromatic carboxylic acid.

[0035] Also, the biodegradable polyester resin composition according to the examples may have a low initial degree of hydrolysis and a high later degree of hydrolysis.

[0036] As a result, the biodegradable polyester resin composition according to the examples can maintain mechanical and chemical physical properties above a certain level within the user's period of use. At the same time, since the biodegradable polyester resin composition according to the examples has a high later degree of hydrolysis, it can be easily decomposed in rivers or the sea. That is, the biodegradable polyester resin composition according to the examples can solve environmental problems such as the marine plastic problem.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0038] Hereinafter, the invention will be described in detail with reference to implementation examples. The implementation examples are not limited to the content disclosed below, and can be modified into various forms as long as the gist of the invention does not change.

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

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

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

[0042] The biodegradable polyester resin composition according to the example contains a biodegradable polyester resin. The biodegradable polyester resin composition according to the example may contain the biodegradable polyester resin alone or together with other resins or additives.

[0043] 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.

[0044] In the description of the biodegradable polyester resin composition according to the example, the diol residue may be represented by a diol. In the biodegradable polyester resin, the dicarboxylic acid residue may be represented by a dicarboxylic acid. Also, the residue may be represented by the component.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The diol may contain 1,4-butanediol or a derivative thereof.

[0049] 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.

[0050] 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.

[0051] The aromatic dicarboxylic acid may contain terephthalic acid, dimethyl terephthalate, or derivatives thereof.

[0052] 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.

[0053] The aliphatic dicarboxylic acid may be at least one selected from the group consisting of adipic acid, succinic acid, sebacic acid, or derivatives thereof.

[0054] The aliphatic dicarboxylic acid may contain adipic acid or a derivative thereof.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate in a content of about 43 mol% to about 53 mol% based on the total dicarboxylic acid.

[0059] The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The biodegradable polyester resin may contain aliphatic dicarboxylic acid residues derived from adipic acid in a content of about 47 mol% to about 57 mol% based on the total dicarboxylic acid.

[0060] Further, the biodegradable polyester resin may include a first block and a second block. The biodegradable polyester resin may have a molecular structure in which the first block and the second block are alternately bonded.

[0061] 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.

[0062] 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.

[0063] 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. Also, in the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks to the number (Y) of the second blocks may be from 0.8 to 1. The number of the first blocks may be even smaller than the number of the second blocks.

[0064] 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.

[0065] The number of the first blocks may vary depending on the content of the aromatic dicarboxylic acid and the molecular weight of the biodegradable polyester resin. That is, as the molar ratio of the aromatic dicarboxylic acid increases and as the molecular weight of the biodegradable polyester resin increases, the number of the first blocks may increase.

[0066] 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.

[0067] The number of the second blocks may vary depending on the content of the aliphatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the degree of alternation described later.

[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. Also, 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. Also, 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 Chemical Formula 1 below.

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

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

[0074]

Chemical Formula

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

[0076] The R3 and the R4 may be a butylene group.

[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, the R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, the R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and the m may be 1 to 20. Further, the R3 and the R4 are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and the n may be 1 to 20.

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

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

[0082] Or, 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] Or, 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 the following Chemical Formula 4, and the second block may be represented by the following Chemical Formula 5.

[0087]

Chemical Formula

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

[0089]

Chemical Formula

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

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

[0092] [Chemical Formula]

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

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

[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 physical properties and appropriate UV resistance properties.

[0096] Since the first block and the second block have the above characteristics, the mechanical physical 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] Since the first block and the second block have the above characteristics, the biodegradable polyester resin composition according to the example may have an appropriate biodegradation rate and improved UV resistance.

[0101] The biodegradable polyester resin may further contain a branching agent. The branching agent may contain a trihydric or higher alcohol and / or a trihydric or higher carboxylic acid. The branching agent can react with the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. As a result, the branching agent may be included as a part of the molecular structure in the biodegradable polyester resin.

[0102] At least one of the trihydric or higher alcohols may be selected from the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0103] The above trivalent or higher carboxylic acid may be at least one selected from the group consisting of methane tricarboxylic acid, ethanetricarboxylic acid, citric acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzenetricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, or benzene-1,2,4,5-tetracarboxylic acid.

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

[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 improved UV characteristics, appropriate mechanical properties, and appropriate biodegradability.

[0106] 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 whole 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 whole 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 whole 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 whole 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 whole 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 whole 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 whole 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 whole composition.

[0107] 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.

[0108] 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.

[0109] The nano-cellulose may be one or more selected from the group consisting of nano-crystalline 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.

[0110] The nano-cellulose may contain a metal bonded by an ionic bond. The nano-crystalline cellulose may contain a sodium element. Further, the nano-crystalline cellulose may contain a sulphate. The nano-crystalline cellulose may contain a carboxylate. The nano-crystalline cellulose may be cellulose hydrogen sulphate sodium salt.

[0111] The nano-cellulose may be represented by Chemical Formula 7 below.

[0112]

Chemical Formula

[0113] Here, x is 1 to 35, and y may be 1 to 10. x is 15 to 35, and y may be 1 to 10.

[0114] The nano-cellulose may have a specific surface area of about 200 m 2 / g to about 600 m 2 / g. The nano-cellulose may have a specific surface area of about 250 m 2 / g to about 500 m 2 / g.

[0115] The weight average molecular weight of the nanocellulose may be about 10,000 g / mol to about 40,000 g / mol. The weight average molecular weight of the nanocrystalline cellulose may be about 11,000 g / mol to about 35,000 g / mol.

[0116] The moisture content of the nanocrystalline cellulose may be about 2 wt% to about 8 wt%. The moisture content of the nanocrystalline cellulose may be about 4 wt% to about 6 wt%.

[0117] The average diameter of the nanocellulose may be about 0.5 nm to about 10 nm. The average diameter of the nanocellulose may be about 1 nm to about 8 nm. The average diameter of the nanocellulose may be about 1.5 nm to about 7 nm.

[0118] The average length of the nanocellulose may be about 20 nm to about 300 nm. The average length of the nanocellulose may be about 30 nm to about 180 nm. The average length of the nanocellulose may be about 35 nm to about 150 nm.

[0119] By the diameter and length of the nanocellulose satisfying the above ranges, the biodegradability and physical properties of the biodegradable polyester resin, or the biodegradable polyester sheet, film and molded article obtained using the same can be further improved.

[0120] The diameter and length of the nanocellulose can be measured by atomic force microscopy in a state dispersed in water.

[0121] The sulfur content of the nanocellulose may be about 0.1 wt% to about 1.2 wt% based on the whole nanocrystalline cellulose. The sulfur content of the nanocrystalline cellulose may be about 0.2 wt% to about 1.1 wt% based on the whole nanocellulose.

[0122] The pH of the nanocellulose may be 5 to 8. The pH of the nanocellulose may be 6 to 8.

[0123] The zeta potential of the nanocellulose may be from about -25 mV to about -50 mV. The zeta potential of the nanocellulose may be from about -30 mV to about -45 mV.

[0124] The nanocellulose may be contained 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 contained 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 contained 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 contained 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.

[0125] Since the nanocellulose has the above characteristics, it can be uniformly dispersed in the biodegradable polyester resin composition according to the examples.

[0126] Since the nanocellulose has the above characteristics, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0127] In addition, the nanocellulose functions as a crystal nucleating agent and can improve the crystallization rate of the biodegradable polyester resin composition according to the examples. As a result, the nanocellulose can increase the crystallization temperature of the biodegradable polyester resin composition according to the examples.

[0128] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have appropriate UV resistance characteristics.

[0129] Since the nanocellulose has the above characteristics, the biodegradable polyester resin composition according to the examples may have an appropriate biodegradation rate.

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

[0131] The biodegradable polyester resin composition according to the examples may contain a metal salt.

[0132] 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.

[0133] At least one or more of the metal salts may be selected from the group consisting of nitrates, sulfates, hydrochlorides, or carboxylates. At least one or more of the metal salts may be selected from the group consisting of titanium salts, silicon salts, sodium salts, calcium salts, potassium salts, magnesium salts, copper salts, iron salts, aluminum salts, or silver salts. At least one or more of the metal salts may be selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, or sodium nitrate.

[0134] 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).

[0135] Also, the metal salt may be selected from the group consisting of acetate, nitrate, nitride, sulfide, sulfate, sulfoxide, hydroxide, hydrate, chloride, chlorinate, and bromide.

[0136] Since the biodegradable polyester resin composition according to the example contains the metal salt in the above content, the hydrolysis rate and the biodegradation rate can be appropriately adjusted.

[0137] The biodegradable polyester resin composition according to the example may further contain a hydrolysis-resistant agent.

[0138] The hydrolysis-resistant agent may be selected from at least one or more silicon-based compounds such as silane, silazane, or siloxane.

[0139] 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 selected from the group consisting of 3-glycidyloxypropyltriethoxysilane (γ-Glycidyloxypropyltriethoxysilane), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), 3-glycidoxypropylmethyldimethoxysilane (3-Glycidoxypropyl methyldimethoxysilane), 3-glycidoxypropyltrimethoxysilane (3-Glycidoxypropyl trimethoxysilane), 3-glycidoxypropylmethyldiethoxysilane (3-Glycidoxypropyl methyldiethoxysilane), or 3-glycidoxypropyltriethoxysilane (3-Glycidoxypropyl triethoxysilane).

[0140] 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 30,000 ppm based on the weight of the entire composition. 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 5 ppm to 5000 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 3000 ppm.

[0141] The hydrolysis-resistant agent may be bonded to the biodegradable polyester resin. The hydrolysis-resistant agent may be chemically bonded to the biodegradable polyester resin. The hydrolysis-resistant agent may be chemically bonded to a polymer contained in the biodegradable polyester resin. The hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin to each other.

[0142] 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.

[0143] 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 a silicon element at a content of about 0.1 ppm to about 1000 ppm. The biodegradable polyester resin composition according to the examples may contain a silicon element at a content of about 0.1 ppm to about 500 ppm. The biodegradable polyester resin composition according to the examples may contain a silicon element at a content of about 0.1 ppm to about 100 ppm.

[0144] Also, 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.

[0145] Also, the hydrolysis-resistant agent can couple the polymers contained in the biodegradable polyester resin, so that the proportion of high-molecular-weight polymers in the biodegradable polyester resin composition according to the examples can be increased. As a result, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0146] The biodegradable polyester resin composition according to the embodiment may further contain a chain extender.

[0147] The chain extender may contain isocyanate.

[0148] The chain extender may be at least one selected from the group consisting of monofunctional isocyanate or polyfunctional isocyanate.

[0149] The chain extender may be at least one selected from the group consisting of tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate, and 2,4'-diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and methylene bis(4-isocyanatocyclohexane).

[0150] The chain extender may contain triisocyanate. The chain extender may contain tris(4-isocyanatophenyl)methane.

[0151] 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.

[0152] The chain extender may contain a styrene copolymer. The chain extender may contain styrene glycidyl acrylate.

[0153] The chain extender may be chemically bonded to the biodegradable polyester resin. The chain extender may be chemically bonded to a polymer contained in the biodegradable polyester resin. The chain extender may be bonded to the end of a polymer contained in the biodegradable polyester resin. Further, the chain extender may be bonded to the ends of three polymers contained in the biodegradable polyester resin.

[0154] The chain extender may be contained in the biodegradable polyester resin composition according to the examples at a content of about 0.1 wt% to about 10 wt%. The chain extender may be contained in the biodegradable polyester resin composition according to the examples at a content of about 0.2 wt% to about 8 wt%. The chain extender may be contained in the biodegradable polyester resin composition according to the examples at a content of about 0.3 wt% to about 7 wt%.

[0155] 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.

[0156] Further, the chain extender can also 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.

[0157] Further, the chain extender couples the polymers contained in the biodegradable polyester resin, and the biodegradable polyester resin composition according to the examples can increase the proportion of high-molecular-weight polymers. Thereby, the mechanical properties of the biodegradable polyester resin composition according to the examples can be improved.

[0158] The biodegradable polyester resin composition according to the examples may contain a heat stabilizer. The heat stabilizer may be a phosphorus-based heat stabilizer.

[0159] 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.

[0160] Further, the heat stabilizer may be an antioxidant having an antioxidant function.

[0161] 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. Further, the heat stabilizer can suppress the activation of a titanium-based catalyst or the like and adjust the reaction rate.

[0162] The biodegradable polyester resin composition according to the example may contain an elongation improver. Examples of the elongation improver may include oils such as paraffin oil, naphthene oil, or aromatic oil, or those having adipates such as dibutyl adipate, diethylhexyl adipate, dioctyl adipate, or diisopropyl adipate.

[0163] The elongation rate improver may be included in the biodegradable polyester resin composition according to the examples at a content of about 0.001 parts by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin. The elongation rate improver may be included in the biodegradable polyester resin composition according to the examples at a content of about 0.01 parts by weight to about 1 part by weight based on 100 parts by weight of the biodegradable polyester resin.

[0164] The biodegradable polyester resin composition according to the examples 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.

[0165] Regarding the inorganic filler, the particle size (D 50 ) at which the cumulative volume is 50% based on the volume in the particle size distribution obtained by the laser diffraction method 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.

[0166] Also, the specific surface area of the inorganic filler may be about 100 m 2 / g or more. For example, the specific surface area of the inorganic filler may be about 100 m 2 / g or more, about 105 m 2 / g or more, or about 110 m 2 / g or more.

[0167] 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.

[0168] 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.

[0169] Since the biodegradable polyester resin composition according to the examples contains the inorganic filler in the above content, the biodegradable polyester resin composition according to the examples may have mechanical properties, appropriate UV resistance characteristics, an appropriate biodegradation rate, and an appropriate hydrolysis rate.

[0170] The biodegradable polyester resin composition according to the examples may further include two types of biodegradable resins. The biodegradable polyester resin composition according to the examples may be a composite resin composition containing two or more types of resins, fillers, and additives.

[0171] At least one or more of the two types of biodegradable resins may be selected from the group consisting of polybutylene azelate terephthalate (PBAzT), polybutylene sebacate terephthalate (PBSeT), polybutylene succinate terephthalate (PBST), polyhydroxyalkanoate (PHA), or polylactic acid (PLA).

[0172] 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.

[0173] The two biodegradable resins can complement the 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 the mechanical properties, appropriate UV resistance, appropriate biodegradation rate, and appropriate hydrolysis rate of the biodegradable polyester resin composition according to the examples.

[0174] The process of manufacturing the biodegradable polyester resin composition according to the examples is as follows.

[0175] Referring to FIG. 1, the manufacturing apparatus for the biodegradable polyester resin includes a slurry stirrer 100, an esterification reaction unit 200, a polycondensation reaction unit 300, a post-treatment unit 400, a first recovery unit 510, and a second recovery unit 520.

[0176] The method for manufacturing the biodegradable polyester resin includes the step of manufacturing a slurry containing the diol and the aromatic dicarboxylic acid.

[0177] The step of manufacturing the slurry includes the step of mixing and processing the diol and the aromatic dicarboxylic acid. That is, the step of manufacturing the slurry is a pretreatment step before the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid to form a slurry. At this time, the diol may contain a biomass-based diol component.

[0178] 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.

[0179] The diol and the aromatic dicarboxylic acid can be put into the slurry stirrer 100 and stirred to manufacture the slurry.

[0180] By mixing and pretreating 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 accelerating the esterification reaction rate, so the reaction efficiency can be increased.

[0181] In particular, when the aromatic dicarboxylic acid has complete crystallinity and is in powder form, such as terephthalic acid, its solubility in the diol is very low, and a homogeneous reaction may not easily occur. Therefore, the pretreatment process of forming a slurry plays a very important role in providing biodegradable polyester resins, sheets, films, and molded products having excellent physical properties according to embodiments of the present invention and enhancing the reaction efficiency.

[0182] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid has complete crystallinity, has no melting point, and is a white crystal that sublimes at nearly 300 °C under normal pressure. Its solubility in the diol is very low, and a homogeneous reaction is difficult to occur. Therefore, when a pretreatment process is performed before the esterification reaction, since it reacts with the diol within the solid matrix of terephthalic acid, the surface area can be increased to induce a uniform reaction.

[0183] Also, when the aromatic dicarboxylic acid is dimethyl terephthalate, the pretreatment process can melt the dimethyl terephthalate at about 142 °C to 170 °C and react it with the diol, so that the esterification reaction rate can be made faster and more efficient.

[0184] On the other hand, in the pretreatment stage of manufacturing the slurry, the structure and physical properties of the biodegradable polyester resin may vary depending on the particle size, particle size distribution, pretreatment reaction conditions, etc. of the aromatic dicarboxylic acid.

[0185] For example, the aromatic dicarboxylic acid contains terephthalic acid, and the average particle size (D50) of the terephthalic acid measured by a particle size analyzer Microtrac S3500 in the particle size distribution (PSD) may be 10 μm to 400 μm, and the standard deviation with respect to the average particle size (D50) may be 100 or less. The standard deviation means the square root of the dispersion. The average particle size (D50) of the terephthalic acid may be 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 the diol and the reaction rate.

[0186] In the pretreatment process, the diol and the aromatic dicarboxylic acid can be mixed and put into a slurry stirrer 100 (tank).

[0187] The slurry stirrer 100 may be, for example, one with an anchor - type bottom, a height to the agitator of 20 mm or more, and equipped with three or more rotating blades, which may be more advantageous for achieving an efficient stirring effect.

[0188] For example, in the slurry stirrer 100, the height to the agitator may be 20 mm or more, that is, there may be almost no space between the reactor and the bottom of the agitator. In this case, a slurry can be obtained without precipitation. If the pattern, form, and rotating blades of the agitator do not meet the above conditions, when the diol and the aromatic dicarboxylic acid are initially mixed, the aromatic dicarboxylic acid may settle to the bottom, and in this case, phase separation may occur.

[0189] The pretreatment step of manufacturing the slurry may include a step of mixing the diol and the aromatic dicarboxylic acid and stirring at about 30°C to about 100°C, at about 50 rpm to about 200 rpm for 10 minutes or more, for example, for 10 minutes to 200 minutes.

[0190] The diol may have the characteristics as described above.

[0191] 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.

[0192] The aromatic dicarboxylic acid may have the same characteristics as described above.

[0193] 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.

[0194] When the diol is charged in a larger amount than the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be easily dispersed.

[0195] In addition, an additive can be charged into the slurry. The nanocellulose and / or the metal salt may be added to the slurry in the form of a dispersion or a solution.

[0196] The method for producing the biodegradable polyester resin esterifies a slurry obtained by mixing and pretreating a diol and an aromatic dicarboxylic acid to obtain a prepolymer, and then subjecting the prepolymer to a polycondensation reaction, whereby the structure and physical properties of the target biodegradable polyester resin according to an embodiment of the present invention can be efficiently achieved.

[0197] The method for producing the biodegradable polyester resin includes a step of esterifying the slurry and the aliphatic dicarboxylic acid to produce a prepolymer. The slurry and the aliphatic dicarboxylic acid can react in the ester reaction section.

[0198] In the esterification reaction, by using the slurry, the reaction time can be shortened. For example, the slurry obtained in the pretreatment step can shorten the reaction time of the ester reaction by 1.5 times or more.

[0199] 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.

[0200] In one embodiment, the esterification reaction can be carried out once after charging an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid into the slurry. That is, the slurry is introduced into the esterification reactor, and the esterification reaction can be carried out by introducing the aliphatic dicarboxylic acid alone, or the aliphatic dicarboxylic acid and the diol into the esterification reactor.

[0201] The diol and the aliphatic dicarboxylic acid may be added to a slurry containing the aromatic dicarboxylic acid in a slurry form.

[0202] 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.

[0203] In the esterification reaction, the molar number of the total diol charged may be about 1.0 to about 1.8 relative to the total molar number of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. In the esterification reaction, the molar number of the total diol charged may be about 1.1 to about 1.6 relative to the total molar number of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0204] 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.

[0205] Also, various additives such as the nanocellulose may be added to the slurry of the diol and the aliphatic dicarboxylic acid.

[0206] 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.

[0207] In one embodiment, the slurry, the aliphatic dicarboxylic acid, and the diol can be mixed to carry out a first esterification reaction. At this time, in the reaction mixture for carrying out the first esterification reaction, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be 1:0.05 to 1:0.5.

[0208] Further, after the first ester reaction, a mixture of the slurry, the aliphatic dicarboxylic acid, and the diol can be introduced into the esterification reaction section to carry out a second ester reaction together with the first ester reaction product. At this time, in the mixture introduced in the second esterification reaction, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid may be 0.05:1 to 0.5:1.

[0209] The first ester reaction can be carried out at 250°C or lower for 1.25 hours to 4 hours. Specifically, the first esterification reaction can be carried out at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C under normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the first esterification reaction can be carried out for 1.25 hours to 4 hours, 1.25 hours to 3.5 hours, or 2.5 hours to 3 hours, but is not limited thereto.

[0210] The second ester reaction can be carried out at about 250°C or lower for 0.25 hours to 3.5 hours. Specifically, the second esterification reaction can be carried out at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C under normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the second esterification reaction can be carried out for 0.5 hours to 3 hours, 1 hour to 2.5 hours, or 1.5 hours to 2.5 hours, but is not limited thereto.

[0211] 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 to be introduced are adjusted respectively, so that 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.

[0212] In addition, in the second esterification reaction, the branching agent can be further introduced. That is, the slurry, the mixture of the aliphatic dicarboxylic acid, the diol, the branching agent, and the product of the first esterification reaction can react to form the prepolymer. The characteristics and content of the branching agent may be the same as those described above.

[0213] The prepolymer can be formed by the second esterification reaction.

[0214] 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 8500 g / mol, about 500 to about 8000 g / mol, about 500 to about 7000 g / mol, about 500 g / mol to about 5000 g / mol, or about 800 g / mol to about 4000 g / mol. By satisfying the above range of the number average molecular weight of the prepolymer, the molecular weight of the polymer in the polycondensation reaction can be efficiently increased.

[0215] 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 them, the molecular weight can be measured based on the number average molecular weight (Mn).

[0216] The reinforcing material and / or the metal salt may be introduced together with the slurry before the esterification reaction. The reinforcing material and / or the metal salt may be introduced into the esterification reaction section 200 during the esterification reaction. The reinforcing material and / or the metal salt may be introduced into the ester reaction product after the esterification reaction. Further, the reinforcing material and / or the metal salt may be introduced together with the aliphatic dicarboxylic acid. Further, the reinforcing material 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.

[0217] Since the reinforcing material and / or the metal salt are introduced into the esterification reaction, the reinforcing material and / or the metal salt may be uniformly dispersed in the biodegradable polyester resin.

[0218] The reinforcing material may have the characteristics described above. In particular, the nanocellulose can be used as the reinforcing material.

[0219] 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 ultrasonically pretreated with water-dispersed nanocellulose.

[0220] For now, the bead mill pretreatment can be performed with a vertical mill or a horizontal mill as a wet milling device. Although the horizontal mill is preferable in that it can hold a larger amount of beads inside the chamber, reduces mechanical uneven wear, reduces bead wear, and is easy to maintain, it is not limited thereto.

[0221] The bead mill pretreatment can be carried out using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0222] 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.

[0223] By having the bead diameter satisfy the above range, the dispersibility of nanocellulose can be further improved. When the bead diameter exceeds the above range, the average particle size and particle size deviation of nanocellulose may increase, resulting in lower dispersibility.

[0224] Also, it is preferable to use beads with a higher specific gravity than that of nanocellulose in the bead mill pretreatment in terms of sufficient energy transfer. For example, the beads may be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide, which have a higher specific gravity than the water-dispersed nanocellulose. Zirconium beads having a specific gravity more than 4 times higher than that of the water-dispersed nanocellulose are preferred, but not limited thereto.

[0225] Also, the ultrasonic pretreatment is a method of physically closing or pulverizing nanoparticles by waves generated by releasing ultrasound at 20 kHz into a solution.

[0226] The ultrasonic pretreatment can be carried out at an output of 30,000 J / s or less for a time of less than 30 minutes. For example, the ultrasonic pretreatment can be carried out at an output of 25,000 J / s or less or 22,000 J / s or less for a time of 25 minutes or less, 20 minutes or less, or 18 minutes or less. By satisfying the above ranges for the output and the implementation time, the effect of the ultrasonic pretreatment, that is, the improvement of dispersibility, can be maximized. If the output exceeds the above range, on the contrary, the nanoparticles may re-aggregate and the dispersibility may become low.

[0227] 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.

[0228] 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.

[0229] Since the nanocellulose contains ionically bonded metal, its dispersibility in water is very high. Also, a very 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 aqueous dispersion of the nanocellulose may be about 1 wt% to about 50 wt%.

[0230] A titanium-based catalyst and / or a germanium-based catalyst can be used for 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.

[0231] Also, before the first esterification reaction, the titanium-based catalyst and / or the germanium-based catalyst may be added to the slurry, and the titanium-based catalyst and / or the germanium-based catalyst may be further added to the product of the first esterification reaction.

[0232] 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.

[0233] Also, 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.

[0234] Also, the heat stabilizer may be introduced together with the slurry before the esterification reaction. The heat stabilizer may be introduced into the esterification reaction section 200 during the esterification reaction. The heat stabilizer may be introduced into the ester reaction product after the esterification reaction. Also, the heat stabilizer may be introduced together with the aliphatic dicarboxylic acid. Also, the heat stabilizer may be introduced into the esterification reaction section 200 after the first ester reaction and before the second ester reaction.

[0235] The characteristics of the heat stabilizer may be the same as those described above.

[0236] 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.

[0237] After the esterification reaction is completed, one or more selected from the group consisting of additives such as silica, potassium, or magnesium, and color correctors such as cobalt acetate may be further added to the esterification reaction product. That is, after the esterification reaction is completed, the additive and / or color corrector can be added and stabilized, and then the polycondensation reaction can be carried out. The additive and / or the color corrector may be added after the esterification reaction is completed and introduced into the polycondensation reaction section 300 together with the prepolymer. Thereby, the additive and / or the color corrector may be uniformly dispersed in the biodegradable polyester resin.

[0238] 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.

[0239] Further, the first recovery unit 510 recovers reaction by-products such as water from the esterification reaction unit 200. The first recovery unit 510 can recover the by-products generated in the esterification reaction by applying a vacuum pressure to the esterification reaction unit 200 or performing reflux.

[0240] 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.

[0241] The prepolymer is introduced into the polycondensation reaction unit 300. Further, 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 unit 300 together with the prepolymer.

[0242] 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 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.

[0243] Further, the polycondensation reaction may include a primary polycondensation and a secondary polycondensation.

[0244] For example, the first polycondensation can be carried out at about 260°C or lower, about 250°C or lower, about 215°C to about 250°C, about 215°C to about 245°C, or about 230°C to about 245°C, at about 1 torr to about 200 torr, about 2 torr to about 100 torr, about 4 torr to about 50 torr, about 5 torr to about 45 torr, or about 8 torr to about 32 torr, for about 0.5 hours to about 3.5 hours, about 0.5 hours to about 3.0 hours, or about 0.5 hours to about 2.8 hours.

[0245] Also, the second polycondensation can be carried out at about 220°C to about 265°C, about 230°C to about 260°C or about 235°C to about 255°C, at about 1 torr or lower, about 0.8 torr or lower, about 0.6 torr or lower, about 0.1 torr to about 1 torr, about 0.2 torr to about 0.8 torr, or about 0.2 torr to about 0.6 torr, for about 0.5 hours to about 4 hours, about 1 hour to about 3.5 hours, or about 1.5 hours to about 3.5 hours.

[0246] 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, one or more selected from the group consisting of additives such as silica, potassium or magnesium; amine-based stabilizers such as trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, phosphorous acid, or tetraethylenepentamine; and polymerization catalysts such as antimony trioxide, antimony trioxide or tetrabutyl titanate can be further added to the prepolymer.

[0247] 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.

[0248] Further, the second recovery unit 520 recovers reaction by-products such as water from the polycondensation reaction unit 300. The second recovery unit 520 can apply a vacuum pressure to the polycondensation reaction unit 300 to recover the by-products generated in the polycondensation reaction.

[0249] 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.

[0250] Thereafter, the hydrolysis-resistant agent and / or the chain extender are added to the polymer. Thereafter, the polymer, the hydrolysis-resistant agent, and the chain extender are uniformly mixed and maintained at a temperature of about 200°C to about 260°C for about 1 minute to about 15 minutes. As a result, the polymer reacts with the hydrolysis-resistant agent and / or the chain extender.

[0251] Alternatively, the hydrolysis-resistant agent and / or the chain extender may be added to the polycondensation reaction unit 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 unit 300 may be about 200°C to about 260°C. Also, the reaction time of the hydrolysis-resistant agent and / or the chain extender in the polycondensation reaction unit 300 may be about 1 minute to about 15 minutes.

[0252] The hydrolysis-resistant agent may have the same characteristics as described above.

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

[0254] As a result, the biodegradable polyester resin composition according to the examples may have an appropriate degree of hydrolysis and a high degree of biodegradability.

[0255] Thereafter, pellets can be produced from the polymer.

[0256] 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.

[0257] The cutting step can be carried out without limitation using any pellet cutting machine commonly 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.

[0258] The pellets can undergo further post-treatment processes. The pellets can be fed into the post-treatment unit 400 to carry out the post-treatment processes.

[0259] The post-treatment processes can be carried out within the post-treatment unit 400. The pellets are fed into the post-treatment unit 400. Thereafter, the post-treatment unit 400 can melt the fed pellets by frictional heat and extrude them again. That is, the post-treatment unit 400 may include an extruder such as a twin-screw extruder.

[0260] 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.

[0261] 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.

[0262] Thereafter, the resin extruded by the extruder may be cooled, cut, and processed into post-treated pellets. That is, the resin extruded from the extruder may be reprocessed into pellets by the above-described cutting step.

[0263] The crystallinity of the pellets can be improved in the post-treatment step. Also, the content of the residues contained in the pellets can be adjusted in the post-treatment step. In particular, the content of the oligomers contained in the pellets can be adjusted by the post-treatment step. The content of the residual solvent contained in the pellets can be adjusted by the post-treatment step.

[0264] Thereby, the post-treatment step can appropriately adjust the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable polyester resin.

[0265] After the pellets are manufactured, the biodegradable polyester resin can be compounded with the two biodegradable resins. Also, at least one of the inorganic filler, the light stabilizer, the color corrector, or the other additives can be compounded with the biodegradable polyester resin and the two biodegradable resins.

[0266] The compounding step is as follows.

[0267] The biodegradable polyester resin and the two biodegradable resins are mixed with at least one of the inorganic filler, the heat stabilizer, the color corrector, the metal salt, or the other additives and fed into an extruder. The mixed biodegradable polyester resin composition melts at a temperature of about 120°C to about 260°C in the extruder and mixes with each other. Thereafter, the melt-mixed biodegradable polyester resin composition is extruded, cooled, cut, and re-pelletized. By such a process, the two biodegradable resins can be compounded to produce a biodegradable polyester resin composition according to an example.

[0268] In contrast, the inorganic filler, the heat stabilizer, the color corrector, the metal salt, and the other additives may be added during the process of polymerizing the biodegradable polyester resin.

[0269] The biodegradable polyester resin composition according to the examples can be used to produce a biodegradable polyester film.

[0270] 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.

[0271] The biodegradable polyester film according to the examples may have substantially the same degree of hydrolysis and biodegradability as the above-described biodegradable polyester resin composition.

[0272] On the other hand, the biodegradable polyester film can be produced using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0273] Specifically, the method for producing the biodegradable polyester film may include the step of producing the biodegradable polyester resin composition according to the examples and the step of drying and melt-extruding the biodegradable polyester resin composition.

[0274] In the step of drying and melt-extruding the biodegradable polyester resin composition, the drying can be carried out at about 60°C to about 100°C for about 2 hours to about 12 hours. Specifically, the drying can be carried out at about 65°C to about 95°C, about 70°C to about 90°C, or about 75°C to about 85°C for about 3 hours to about 12 hours or about 4 hours to about 10 hours. By satisfying the above range of the drying process conditions of the pellets, the quality of the produced biodegradable polyester film or molded article can be further improved. The moisture content of the biodegradable polyester resin composition after the drying step may be about 500 ppm or less based on the total weight of the biodegradable polyester resin composition.

[0275] In the step of drying and melt-extruding, the melt-extrusion can be carried out at a temperature of about 250°C or lower. For example, the melt-extrusion can be carried out at a temperature of about 245°C or lower, about 220°C or lower, about 215°C or lower, about 100°C to about 250°C, about 120°C to about 245°C, or about 130°C to about 215°C. The melt-extrusion can be carried out in a blown film process. The melt-extrusion can be carried out with a T-die.

[0276] Also, the film manufacturing process may be a calendaring process.

[0277] A biodegradable polyester molded article can be manufactured using the biodegradable polyester resin.

[0278] Specifically, the molded article can be manufactured by molding the biodegradable polyester resin composition by known methods in the industry such as extrusion and injection. The molded article may be, but is not limited to, an injection molded article, an extrusion molded article, a thin film molded article, a blow molding or blow molded article, a 3D filament, an interior building material, etc.

[0279] 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 fabrics, knitted fabrics, non-woven fabrics, ropes, etc. Further, as shown in FIG. 2, the molded article may be in the form of a disposable container used for food packaging containers such as lunch boxes. Further, the molded article may be molded articles in various forms such as disposable straws, spoons and chopsticks, eating plates, forks, etc.

[0280] In particular, since the molded article can be formed from the biodegradable polyester resin that can improve not only physical properties such as impact absorption energy and hardness but also particularly impact resistance and durability, it is suitable for packaging materials of products stored and transported at low temperatures, automotive interior materials that require durability, garbage bags, mulching films, and disposable products, and can exhibit excellent characteristics.

[0281] The physical properties of the biodegradable film and the biodegradable molded article can be measured in a manner similar to the biodegradable polyester resin composition according to the examples.

[0282] The biodegradable polyester resin composition according to the examples can measure the degree of biodegradability by the following method.

[0283] In order to measure the degree of biodegradability, the biodegradable polyester resin composition according to the above examples was mixed with compost, and a biodegradation acceleration test was carried out at a temperature of 60 ° C and a humidity of 90%. After a certain period of time, the number average molecular weight of the biodegradable polyester resin composition according to the examples was measured using gel permeation chromatography (GPC). The degree of biodegradability was derived from the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain period by the initial number average molecular weight.

[0284] The degree of biodegradability may be represented by the following formula 10.

[0285] [Formula 1] JPEG2025519103000009.jpg13158

[0286] Here, the biodegradable polyester resin composition according to the example is mixed with compost and undergoes a biodegradation acceleration test at a temperature of 60°C and a humidity of 90% for a certain period. Before the biodegradation acceleration test is carried out, the initial number average molecular weight of the biodegradable polyester resin composition and the number average molecular weight after biodegradation of the biodegradable polyester resin composition that has undergone the biodegradation acceleration test for a certain period are measured by gel permeation chromatography (GPC).

[0287] The biodegradability was derived from the value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain period by the initial number average molecular weight.

[0288] 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.

[0289] Also, the manufacturer of the compost may be Taeheung F&G, and the product name of the compost may be Jeongsan soil (by-product fertilizer grade 1 compost).

[0290] Also, when the biodegradability is measured, the biodegradable polyester resin composition according to the example is manufactured into a sheet having a thickness of about 300 μm. Then, the manufactured sheet is cut into a size of about 30 mm × 30 mm to produce flakes. The flakes can be mixed with the compost to perform the biodegradation acceleration test.

[0291] In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 1 week may be about 40% to about 70%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 1 week may be about 45% to about 65%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 1 week may be about 47% to about 63%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 1 week may be about 49% to about 62%.

[0292] In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 2 weeks may be about 50% to about 70%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 2 weeks may be about 55% to about 68%.

[0293] In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 3 weeks may be about 63% to about 75%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 3 weeks may be about 63% to about 73%.

[0294] In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 4 weeks may be about 73% to about 85%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 4 weeks may be 75% to 82%.

[0295] In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 6 weeks may be about 80% to about 90%. In the biodegradable polyester resin composition according to the examples, the biodegradation degree after 6 weeks may be about 82% to about 88%.

[0296] In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 85% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 87% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 88% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 89% or more. In the biodegradable polyester resin composition according to the example, the biodegradation degree after 9 weeks may be about 90% or more.

[0297] In the biodegradable polyester resin composition according to the example, the increase rate of the biodegradation degree from 1 week to 2 weeks may be about 4% / week to about 15% / week. In the biodegradable polyester resin composition according to the example, the increase rate of the biodegradation degree from 1 week to 2 weeks may be about 5% / week to about 13% / week.

[0298] The increase rate of the biodegradation degree may be represented by the following mathematical formula 2.

[0299] [Mathematical formula 2] JPEG2025519103000010.jpg12132

[0300] That is, the increase rate of the biodegradation degree in the mathematical formula 2 means the increase rate of the biodegradation degree from X weeks to Y weeks.

[0301] In the biodegradable polyester resin composition according to the example, the increase rate of the biodegradation degree from 2 weeks to 3 weeks may be about 3% / week to about 10% / week. In the biodegradable polyester resin composition according to the example, the increase rate of the biodegradation degree from 2 weeks to 3 weeks may be about 4% / week to about 9% / week.

[0302] In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 3 weeks to 4 weeks may be about 4% / week to about 10% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 3 weeks to 4 weeks may be about 5% to about 9%.

[0303] In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 4 weeks to 6 weeks may be about 3% / week to about 7% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 4 weeks to 6 weeks may be about 4% / week to about 6% / week.

[0304] In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 6 weeks to 9 weeks may be about 3% / week or less. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 6 weeks to 9 weeks may be about 2% / week or less.

[0305] Also, in the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 1 week to 4 weeks may be about 3% / week to about 10% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of biodegradation from 1 week to 4 weeks may be about 3.5% / week to about 8% / week.

[0306] Since the biodegradable polyester resin composition according to the examples has the degree of biodegradation and the rate of increase in the degree of biodegradation as described above, it may have appropriate durability in the actual living area and may have a high degree of biodegradation when discarded after use.

[0307] The degree of hydrolysis of the biodegradable polyester resin composition according to the examples can be measured by the following method.

[0308] In order to measure the degree of hydrolysis, the biodegradable polyester resin composition according to the above examples is immersed in water at 80°C (100% RH), and then a hydrolysis acceleration test is carried out. After a certain period of time has 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 was 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.

[0309] The degree of hydrolysis may be represented by the following formula 3.

[0310] [Formula 3] JPEG2025519103000011.jpg13155

[0311] Here, the biodegradable polyester resin composition according to the examples is immersed in water at 80°C and then undergoes a hydrolysis acceleration test for a certain period. Before the hydrolysis acceleration test is 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).

[0312] The degree of hydrolysis was 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.

[0313] Also, when the degree of hydrolysis is measured, the biodegradable polyester resin composition according to the examples is made into a sheet having a thickness of about 300 μm. Then, the produced sheet is cut into a size of about 30 mm × 30 mm to produce flakes. The flakes can be immersed in the warm water to perform the hydrolysis acceleration test.

[0314] 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%.

[0315] 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%.

[0316] 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%.

[0317] 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%.

[0318] 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.

[0319] 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.

[0320] In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 25% / week to about 50% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 29% / week to about 50% / week. In the biodegradable polyester resin composition according to the examples, the rate of increase in the degree of hydrolysis from 1 week to 2 weeks may be about 30% / week to about 45% / week.

[0321] The rate of increase in the degree of hydrolysis may be represented by the following Mathematical formula 4.

[0322] [Mathematical formula 4] JPEG2025519103000012.jpg13151

[0323] That is, the rate of increase in the degree of hydrolysis in Mathematical formula 4 means the rate of increase in the degree of hydrolysis from X weeks to Y weeks.

[0324] In the biodegradable resin composition according to the examples, the rate of increase in the degree of hydrolysis from 2 weeks to 3 weeks may be about 3% / week to about 10% / week. In the biodegradable resin composition according to the examples, the rate of increase in the degree of hydrolysis from 2 weeks to 3 weeks may be about 4% to about 8%.

[0325] Also, in the biodegradable resin composition according to the examples, the rate of increase in the degree of hydrolysis from 3 weeks to 6 weeks may be about 0.01% / week to about 3% / week. In the biodegradable resin composition according to the examples, the rate of increase in the degree of hydrolysis from 3 weeks to 6 weeks may be about 0.01% / week to about 2% / week.

[0326] Also, in the biodegradable resin composition according to the examples, the biodegradability per degree of hydrolysis may be 1.35 or more. The biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week. The biodegradability per degree of hydrolysis may be represented by the following Mathematical formula 5.

[0327] Since the biodegradable resin composition according to the examples has a degree of hydrolysis and a rate of increase in the degree of hydrolysis within the above ranges, the biodegradable resin composition according to the examples has appropriate durability in the daily life area and can be easily hydrolyzed when discarded. That is, since the biodegradable resin composition according to the examples has a degree of hydrolysis and a rate of increase in the degree of hydrolysis within an appropriate range, it may have sufficient hydrolysis resistance when used for an appropriate period, such as in disposable packaging. Also, when the biodegradable resin composition according to the examples is discarded in a river or the sea, etc., it can be easily decomposed by hydrolysis and biodegradation, etc., after sufficient time has passed.

[0328] [Formula 5] JPEG2025519103000013.jpg17139

[0329] In the biodegradable resin composition according to the examples, the degree of biodegradation per degree of hydrolysis may be about 1.4 or more. In the biodegradable resin composition according to the examples, the degree of biodegradation per degree of hydrolysis may be about 1.45 or more. In the biodegradable resin composition according to the examples, the degree of biodegradation per degree of hydrolysis may be about 1.47 or more. In the biodegradable resin composition according to the examples, the degree of biodegradation per degree of hydrolysis may be about 1.50 or more. In the biodegradable resin composition according to the examples, the upper limit value of the degree of biodegradation per degree of hydrolysis may be about 5.

[0330] Thereby, the biodegradable polyester resin composition according to the examples may have a high degree of biodegradation while having an appropriately low degree of hydrolysis. In particular, the biodegradable polyester resin composition according to the examples may have a high degree of biodegradation in the later stage while having a low initial degree of hydrolysis.

[0331] As a result, the biodegradable polyester resin composition according to the examples can be efficiently applied to packaging films and the like. That is, the film produced from the biodegradable polyester resin composition according to the examples can be used for normal applications such as packaging. At this time, since the biodegradable polyester resin composition according to the examples has a low degree of hydrolysis initially, 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.

[0332] In addition, since the biodegradable polyester resin composition according to the examples has a degree of biodegradability per high degree of hydrolysis, the film produced from the biodegradable polyester resin composition according to the examples can be easily decomposed when discarded after use.

[0333] Moreover, the biodegradable polyester resin composition according to the examples has a degree of biodegradability per aliphatic carboxylic acid of 1.6 or more. That is, the biodegradable polyester resin composition according to the examples has a low content of aliphatic carboxylic acid and a high degree of biodegradability.

[0334] As a result, since the biodegradable polyester resin composition according to the examples has a relatively high content of aromatic carboxylic acid, it may have high hydrolysis resistance and a high degree of biodegradability.

[0335] Furthermore, the biodegradable polyester resin composition according to the examples may have a low initial degree of hydrolysis and a high later degree of hydrolysis.

[0336] As a result, the biodegradable polyester resin composition according to the examples can maintain mechanical and chemical physical properties above a certain level within the usage period of the user. At the same time, since the biodegradable polyester resin composition according to the examples has a high later degree of hydrolysis, it may be easily decomposed in rivers or the sea. That is, the biodegradable polyester resin composition according to the examples can solve environmental problems such as the marine plastic problem.

[0337] In the biodegradable polyester resin composition according to the embodiment, the biodegradability per aliphatic carboxylic acid may be about 1.7 or more. Further, the biodegradability per aliphatic carboxylic acid may be about 1.75 or more. The biodegradability per aliphatic carboxylic acid may be about 1.79 or more. The biodegradability per aliphatic carboxylic acid may be about 1.8 or more. The biodegradability per aliphatic carboxylic acid may be about 1.85 or more. The biodegradability per aliphatic carboxylic acid may be about 1.90 or more. The maximum value of the biodegradability per aliphatic carboxylic acid may be about 4.

[0338] The biodegradability per aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the ratio of the aliphatic carboxylic acid based on the total dicarboxylic acid. The biodegradability per aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the ratio of the molar% of the aliphatic carboxylic acid based on the total dicarboxylic acid.

[0339] The biodegradability per aliphatic carboxylic acid may be represented by the following formula 6.

[0340] [Formula 6] JPEG2025519103000014.jpg11160

[0341] The composition of the biodegradable polyester resin such as the number of the first blocks, the number of the second blocks, the content of the aliphatic dicarboxylic acid, or the content of the aromatic dicarboxylic acid, the process conditions for producing the biodegradable polyester resin, the reinforcing material, the metal salt, the hydrolysis-resistant agent, the chain extender, the oligomer, or the heat stabilizer, etc. are appropriately adjusted so that the biodegradability per aliphatic carboxylic acid has the above range.

[0342] For example, the hydrolysis-resistant agent and / or the chain extender can couple the polymers contained in the biodegradable polyester resin to impart hydrophobicity to the biodegradable polyester resin composition according to the examples, thereby reducing the initial hydrolysis rate. The reinforcing material, the oligomer and / or the metal salt can accelerate the biodegradation rate of the biodegradable polyester resin composition after a sufficient period of time. That is, the reinforcing material, the oligomer and / or the metal salt can improve the biodegradation degree after 9 weeks. Further, the reinforcing material, the oligomer and / or the metal salt can improve the biodegradation degree after 9 weeks even when the molar ratio of the aliphatic dicarboxylic acid is low. That is, the hydrolysis-resistant agent, the chain extender, the reinforcing material, the oligomer and / or the metal salt can be appropriately combined to realize an appropriate hydrolysis degree and an appropriate biodegradation degree.

[0343] As described above, the biodegradable polyester resin composition according to the examples has a biodegradation degree per high content of aliphatic dicarboxylic acid. Accordingly, the biodegradable polyester resin composition according to the examples has a high biodegradation degree even when it contains an aliphatic dicarboxylic acid at a low content. Accordingly, the biodegradable polyester resin composition according to the examples may have a high content of aromatic dicarboxylic acid and a high biodegradation degree.

[0344] Therefore, the biodegradable polyester resin composition according to the examples has improved physical properties during the actual use period and can be easily biodegradable after use.

[0345] 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 ordinary applications such as packaging. At this time, the biodegradable polyester resin composition according to the examples has a low hydrolysis degree initially, and the biodegradable polyester film can maintain mechanical and chemical physical properties to a certain extent or more within the normal use period of the user.

[0346] 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 can be easily decomposed after use and at the time of disposal.

[0347] At the same time, since the biodegradable polyester resin composition according to the examples has a high degree of hydrolysis in the later stage, it can be easily decomposed not only in soil but also in rivers or the sea. That is, the biodegradable polyester resin composition according to the examples can solve environmental problems such as the marine plastic problem.

[0348] Also, the acid value of the biodegradable polyester resin composition according to the examples may be from about 0.01 mgKOH / g to about 3 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be from about 0.1 mgKOH / g to about 2.5 mgKOH / g. The acid value of the biodegradable polyester resin composition according to the examples may be from about 0.1 mgKOH / g to about 2.3 mgKOH / g.

[0349] 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.

[0350] Also, the biodegradable polyester resin composition according to the examples may contain a nitrogen element. The nitrogen element may be derived from the metal salt and / or the chain extender, etc. The content of the nitrogen element may be from about 0.1 ppm to about 500 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be from about 1 ppm to about 400 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be from about 1 ppm to about 300 ppm based on the biodegradable polyester resin composition according to the examples. The content of the nitrogen element may be from about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples.

[0351] Also, 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. 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 250 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.

[0352] Also, the biodegradable polyester resin composition according to the examples may contain a metal element. The metal element may be derived from the metal salt. The content of the metal element may be about 0.1 ppm to about 500 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 0.5 ppm to about 150 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the examples. The content of the metal element may be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the examples.

[0353] Also, the ratio of the mass of the metal element contained in the metal salt to the silicon element may be about 0.1 to about 0.7. Also, the ratio of the mass of the metal element contained in the metal salt to the silicon element may be about 0.2 to about 0.7. Also, the ratio of the mass of the metal element contained in the metal salt to the silicon element may be about 0.3 to about 0.6.

[0354] Since the content of the nitrogen element, the silicon element, or the metal element is the same as the above range, the biodegradable resin composition according to the example may have an appropriate degree of hydrolysis and an appropriate degree of biodegradability.

[0355] In addition, in the biodegradable polyester resin composition according to the example, the ratios of carbon element, hydrogen element, and oxygen element can be different depending on the diol, the aromatic dicarboxylic acid, the aliphatic dicarboxylic acid, the metal salt, the hydrolysis-resistant agent, and the chain extender. In the biodegradable polyester resin composition according to the example, the number of hydrogen elements based on one carbon atom may be 1.27 to 1.36. In the biodegradable polyester resin composition according to the example, the number of oxygen elements based on one carbon atom may be 0.34 to 0.38.

[0356] The content of the nitrogen element may be measured by an elemental analysis method.

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

[0358] The ratios of the carbon, the hydrogen, and the oxygen can be measured by an elemental analysis method.

[0359] Since the biodegradable polyester resin composition according to the example contains nitrogen, silicon element, metal, carbon, hydrogen, and oxygen within the above ranges, it may have an appropriate degree of hydrolysis resistance and improved biodegradability. As a result, the biodegradable polyester resin composition according to the example has a biodegradability per high degree of hydrolysis, has appropriate durability, and can be used as an environmentally friendly plastic composition, similar to the above.

[0360] In addition, the molded article produced from the biodegradable polyester resin composition according to the example can appropriately maintain its mechanical strength within the normal service period.

[0361] Molded articles manufactured using the biodegradable polyester resin composition according to the embodiment can be efficiently decomposed when disposed of while maintaining required mechanical properties during the actual period of use.

[0362] The above contents will be explained in more detail with reference to the following examples, however, the following examples are for the purpose of illustrating the present invention and are not intended to limit the scope of the examples.

[0363] <Production Example> Production of pretreated cellulose nanocrystals Cellulose nanocrystals (NVC-100, manufacturer: Celluforce) in the form of dry powder with a particle size of about 1 μm to about 50 μm were dispersed in water at 1 wt %, and then ultrasonicated for 1 minute at an output of 20,000 J / s using a tip-type ultrasonic disperser to produce pretreated nanocellulose.

[0364] Hydrolysis stabilizer #1: 3-glycidoxypropylmethyldimethoxysilane Hydrolysis stabilizer #2: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane Metal salts: Iron nitrate Chain extender: Tri(4-isocyanatophenyl)methane

[0365] <Example> Example 1 Manufacturing of biodegradable polyester resin First stage: Pretreatment to obtain slurry As shown in Table 1, the pre-treated nanocellulose, metal salt, 1,4-butanediol (1,4-BDO), and terephthalic acid (TPA) were mixed at a molar ratio of 1,4-BDO:TPA of 1.4:1 and introduced 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. The contents of the pre-treated nanocellulose and the silver nitrate were based on the total weight of the input raw materials.

[0366] Next, the mixture was stirred at 40 °C and 100 rpm for 1 hour for pretreatment to obtain a slurry without phase separation.

[0367] Step 2: Obtaining a prepolymer The slurry obtained in the first step was introduced into a reactor through a supply line. After introducing 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.

[0368] To the reaction product, 1,4-butanediol (1,4-BDO) based on the total molar number of the diol component, adipic acid (AA) based on the total molar number of the dicarboxylic acid component, and tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), a titanium-based catalyst, were introduced at 200 ppm 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 1200 g / mol.

[0369] Step 3: Performing a polycondensation reaction To the prepolymer obtained in the second stage, 150 ppm of tetrabutyl titanate (manufactured by Dupont, Tyzor TnBT), which is a titanium-based catalyst, and 500 ppm of triethylene phosphate stabilizer were added based on the total weight of the prepolymer, and it was stabilized for about 10 minutes. Then, after raising the temperature of the reaction mixture to 250°C, a polycondensation reaction was carried out at 0.5 torr for 4 hours to produce a polymer having a number average molecular weight of 55,000 g / mol.

[0370] Thereafter, about 1000 ppm of 3-glycidoxypropylmethyldimethoxysilane based on the polymer and about 0.5 wt% of tri(4-isocyanatophenyl)methane based on the polymer were added to the polymer. Then, the terminal group extension reaction was carried out on the polymer 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.

[0371] Examples 2 to 6 and Comparative Examples 1 to 3 As shown in Table 1 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, metal salt, hydrolysis-resistant agent, and chain extender are different. Except for the said content and the said process, other processes were carried out with substantial reference to Example 1.

[0372] Examples 7 to 13 and Comparative Example 4 As shown in Tables 2 and 3 below, the contents of adipic acid, terephthalic acid, cellulose nanocrystal, metal salt, hydrolysis-resistant agent, and chain extender are different. Except for the said content and the said process, other processes were carried out with substantial reference to Example 1.

[0373] Production of biodegradable polyester sheet After preparing two Teflon (registered trademark) sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was positioned on one Teflon (registered trademark) sheet. After putting about 7 g of the manufactured polyester resin pellets into the stainless steel (SUS) frame (area 12 cm × 12 cm), it was covered with the other Teflon (registered trademark) sheet and positioned at the center of a hot press (manufacturer: Withrap, model name: WL1600SA) having a surface size of about 25 cm × 25 cm. This was maintained at about 210 °C under a pressure of about 10 Mpa for about 3 minutes, then detached, and immediately cooled with water at about 20 °C for about 30 seconds, and a biodegradable polyester sheet with an area of about 10 cm × 10 cm and a thickness of about 300 μm was manufactured.

[0374] Manufacture of Biodegradable Polyester Film After drying the biodegradable polyester resin pellets at 80 °C for 5 hours, using a blown film extrusion line (manufacturer: Ujin Engineering), melt extrusion was performed at 160 °C to manufacture a biodegradable polyester film with a thickness of 50 μm.

[0375]

Table 1

[0376]

Table 2

[0377]

Table 3

[0378] <Evaluation Example> Evaluation Example 1: Average Particle Size (D50) and Standard Deviation <Average Particle Size (D50) and Standard Deviation of Aromatic Dicarboxylic Acid> The average particle size (D50) and standard deviation (SD, Standard Deviation) of the aromatic dicarboxylic acid (TPA or DMT) were determined under the following conditions using a particle size analyzer Microtrac S3500 (Microtrac Inc) in the particle size distribution (PSD): Use environment - Temperature: 10~35 °C, Humidity: 90%RH, non-condensing maximum - D50 and SD, which are the average particle size distributions by interval, were measured.

[0379] The standard deviation means the square root of the variance and can be calculated using software.

[0380] <Particle size of nanocellulose> For nanocellulose, the particle size and particle size deviation were measured by the principle of dynamic light scattering (DLS) using a Zetasizer Nano ZS (manufacturer: Marven) at a temperature of 25 °C and a measurement angle of 175°. At this time, the peak value derived from the polydispersity index (PdI) in the confidence interval of 0.5 was measured as the particle size.

[0381] Evaluation Example 2: Degree of hydrolysis The biodegradable polyester resins produced in the examples and comparative examples were immersed in water at 80 °C (100% RH), and then a hydrolysis acceleration test was carried out.

[0382] 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 would not evaporate, and a hydrolysis acceleration test was carried out at 80 °C in a convection (hot air) oven. The humidity environment of the biodegradable polyester sheet is the same as that when immersed in water at 100% RH.

[0383] Using gel permeation chromatography (GPC), the number average molecular weight of the polyester resins of the examples and comparative examples was measured after a certain period of time. The value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period of time by the initial number average molecular weight was derived as the degree of hydrolysis.

[0384] The GPC equipment and measurement conditions are as follows. 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

[0385] Evaluation Example 3: Biodegradability The biodegradable polyester resins produced in the examples and comparative examples were mixed with the following compost, and a biodegradation acceleration test was carried out at a temperature of 60 °C and a humidity of 90%.

[0386] Using the gel permeation chromatography (GPC), the number average molecular weight of the polyester resins of the examples and comparative examples was measured after a certain period of time. The value obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period of time by the initial number average molecular weight was derived as the biodegradability.

[0387] 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 preparation

[0388] Evaluation Example 4: Elemental analysis The biodegradable resin compositions in the examples and comparative examples were analyzed by a flash smart elemental analyzer (ThermoFisher).

[0389] In the examples and comparative examples, the biodegradable resin compositions were oxidized to CO2, H2O, NO2, and SO2 at a temperature of about 1000 °C using a catalyst, and the generated gases were separated by a GC column. Subsequently, they were detected by a TCD (Thermal Conductive Detector), and calibration curves for each C, H, N, and S were derived using standard substances (CAS no. 7128-64-5, 63-74-1, 56-89-3, 86-73-7), and the content of each element in the GC chromatogram could be quantified as atomic % or weight %.

[0390] Evaluation Example 5: Acid Value KOH and ethanol were mixed to produce a 0.02N KOH solution. Subsequently, about 1 g of the biodegradable resin composition according to the examples and comparative examples was dissolved in chloroform. Then, using the phenolphthalein reagent as a reference, the biodegradable resin composition solution was titrated with the KOH solution to measure the acid value. Acid Value Measurement Equipment: Mettler toledo Titrator Excellence T5

[0391] As described in Tables 4 and 5 below, the biodegradability was measured.

[0392]

Table 4

[0393]

Table 5

[0394] As described in Tables 6 and 7 below, the hydrolysis degree was measured.

[0395]

Table 6

[0396]

Table 7

[0397] As described in Table 8 below, the biodegradability per degree of hydrolysis has been derived.

[0398]

Table 8

[0399] As described in Table 9 below, the biodegradability per aliphatic dicarboxylic acid has been derived.

[0400]

Table 9

[0401] As in Tables 10 and 11 below, the contents of carbon, hydrogen, nitrogen, sulfur, and oxygen have been measured.

[0402]

Table 10

[0403]

Table 11

[0404] As in Table 12 below, the contents of iron element and silicon element have been measured.

[0405]

Table 12

[0406] As described in Tables 4 to 12 above, the biodegradable resin composition according to the examples may have a biodegradability per high degree of hydrolysis. That is, the biodegradable resin composition according to the examples may have a high final biodegradability while having a low initial degree of hydrolysis.

Industrial Applicability

[0407] The examples can be used for biodegradable resin compositions, films, and molded articles.

Claims

1. A biodegradable molded article comprising a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, having a biodegradability per degree of hydrolysis of 1.4 or more, wherein the biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week, and the biodegradability after 9 weeks and the degree of hydrolysis after 1 week are measured by the following measurement method. [Measurement method] The biodegradability after 9 weeks is the rate of decrease in molecular weight of the biodegradable molded article relative to the initial value when the biodegradable molded article is processed into flakes having a thickness of 300 μm and a size of 30 mm × 30 mm and placed under composting conditions at a temperature of 60 °C and a humidity of 90% for 63 days, and the degree of hydrolysis after 1 week is the rate of decrease in molecular weight of the biodegradable molded article relative to the initial value when the flakes are placed under conditions of a temperature of 80 °C and a humidity of 100% for 7 days.

2. Containing nanocellulose containing a metal, having an average diameter of 0.5 nm to 10 nm and an average length of 20 nm to 300 nm. The biodegradable molded article according to Claim 1.

3. Further containing a metal salt and a silicon element, wherein the ratio of the mass of the metal element contained in the metal salt to the silicon element is 0.1 to 0.7, The biodegradable molded article according to Claim 2.

4. A biodegradable polyester resin composition comprising a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, having a biodegradability per degree of hydrolysis of 1.35 or more, wherein the biodegradability per degree of hydrolysis is a value obtained by dividing the biodegradability after 9 weeks by the degree of hydrolysis after 1 week, and the biodegradability after 9 weeks and the degree of hydrolysis after 1 week are measured by the following measurement method. [Measurement method] The biodegradability after 9 weeks is the rate of decrease in molecular weight of the polyester resin relative to the initial value when the biodegradable polyester resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm × 30 mm and placed under composting conditions at a temperature of 60 °C and a humidity of 90% for 63 days, and the degree of hydrolysis after 1 week is the rate of decrease in molecular weight of the polyester resin relative to the initial value when the flakes are placed under conditions of a temperature of 80 °C and a humidity of 100% for 7 days.

5. The biodegradability after 9 weeks is 75% or more, and the degree of hydrolysis after 1 week is 60% or less, The biodegradable polyester resin composition according to Claim 4.

6. The biodegradability after 1 week is 45% to 75%, The biodegradability after one week is the reduction rate of the molecular weight of the flakes relative to the initial state when the flakes are placed under composting conditions, at a temperature of 60°C and a humidity of 90% for 7 days. The biodegradable polyester resin composition according to claim 4.

7. The degree of hydrolysis after 9 weeks is 80% or more. The degree of hydrolysis after 9 weeks is the reduction rate of the molecular weight of the flakes relative to the initial state when the flakes are placed under conditions of a temperature of 80°C and a humidity of 100% for 63 days. The biodegradable polyester resin composition according to claim 4.

8. The acid value is 2.0 mgKOH / g or less. The biodegradable polyester resin composition according to claim 4.

9. The increase rate of biodegradability from 1 week to 4 weeks is 3.5% / week to 8% / week. The biodegradable polyester resin composition according to claim 4.

10. The increase rate of the degree of hydrolysis from 1 week to 2 weeks is 29% / week to 50% / week. The increase rate of the degree of hydrolysis from 3 weeks to 6 weeks is 0.01% / week to 3% / week. The biodegradable polyester resin composition according to claim 9.

11. The increase rate of the degree of hydrolysis from 2 weeks to 3 weeks is 3% / week to 10% / week. The biodegradable polyester resin composition according to claim 9.

12. Contains a metal salt and a silicon element. The ratio of the mass of the metal element contained in the metal salt to the silicon element is 0.1 to 0.

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

13. Contains a polyester resin containing a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The biodegradability per aliphatic carboxylic acid is 1.7 or more. The biodegradability per aliphatic carboxylic acid is the value obtained by dividing the biodegradability after 9 weeks by the ratio of the aliphatic dicarboxylic acid in the total dicarboxylic acids. The biodegradability after 9 weeks is 85% or more. The biodegradability after 9 weeks is measured by the following measurement method. Biodegradable polyester resin composition. [Measurement method] The biodegradability after 9 weeks is the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to the initial state when the composition is placed under composting conditions, at a temperature of 60°C and a humidity of 90% for 9 weeks.

14. The biodegradability after 9 weeks is 88% or more. The biodegradable polyester resin composition according to claim 13.

15. The biodegradability after 1 week is 45% to 65%. The biodegradability after one week is the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to its initial value when the biodegradable polyester resin composition is placed under composting conditions, at a temperature of 60°C and a humidity of 90% for one week. The biodegradable polyester resin composition according to claim 13.

16. The biodegradability after two weeks is 55% to 70%, The biodegradability after two weeks is the reduction rate of the molecular weight of the biodegradable polyester resin composition relative to its initial value when the biodegradable polyester resin composition is placed under composting conditions, at a temperature of 60°C and a humidity of 90% for two weeks. The biodegradable polyester resin composition according to claim 14.

17. The increase rate of biodegradability from one week to two weeks is about 4% / week to about 15% / week, The biodegradable polyester resin composition according to claim 16.

18. The biodegradability after four weeks is 73% to 85%, The biodegradability after four weeks is the reduction rate of the number average molecular weight of the biodegradable polyester resin composition relative to its initial value when the biodegradable polyester resin composition is placed under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100% for four weeks. The increase rate of biodegradability from one week to four weeks is 3.5% / week to 8% / week, The biodegradable polyester resin composition according to claim 13.

19. The degree of hydrolysis after one week is 35% to 60%, 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 its initial value when the biodegradable polyester film is placed under high temperature and high humidity conditions of a temperature of 80°C and a humidity of 100% for one week. The biodegradable polyester resin composition according to claim 13.

20. Containing a nitrogen element, The biodegradable polyester resin composition according to claim 13.

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