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

Abstract

Embodiments provide a biodegradable polyester resin composition comprising: a polyester resin comprising a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a fiber-based reinforcing material wherein the first turbidity change rate of the fiber-based reinforcing material is less than 15%, thereby achieving improved physical properties.

Description

TECHNICAL FIELD

[0001] Embodiments relate to a biodegradable polyester resin composition, a biodegradable polyester film including the same, and a biodegradable molded article including the same. BACKGROUND

[0002] In recent years, as concerns about environmental issues have increased, there has been a growing demand for disposal solutions for various daily necessities, especially disposable products. Specifically, polymeric materials are widely used to manufacture various products, such as films, fibers, packaging materials, bottles, and containers, due to their low cost and excellent processability. However, when the useful life of these products ends, incineration can release harmful substances, and natural decomposition can take hundreds of years to complete, depending on the type of product.

[0003] To overcome these limitations of polymers, research is actively being conducted on biodegradable polymers that can be decomposed in a short period of time. Such biodegradable polymers, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polybutylene succinate (PBS), are being used.

[0004] With respect to such biodegradable resin compositions, Korean Patent Publication No. 2012-0103158, etc., have been disclosed. SUMMARY

[0005] TECHNICAL PROBLEM

[0006] Accordingly, the present invention has been made to address the above-mentioned problems, and it is an object of the present invention to provide a biodegradable polyester resin composition having appropriately improved mechanical properties, heat resistance, and electrical properties, a biodegradable polyester film including the same, and a biodegradable molded article including the same.

[0007] TECHNICAL SOLUTION

[0008] According to an aspect of the present invention, the above and other objects can be achieved by providing a biodegradable polyester resin composition including: a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a fiber reinforcing material, wherein a first haze change rate of the fiber reinforcing material, as measured by the following method, is less than 15%:

[0009] [MEASURING METHOD]

[0010] 1) The fiber reinforcing material was dispersed in water at a concentration of 1 wt% at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber reinforcing material.

[0011] 2) The aqueous dispersion is left to stand at room temperature for 2 days, re-dispersed at 120 rpm for 1 minute, and the first turbidity of the aqueous dispersion is measured.

[0012] 3) The aqueous dispersion is left to stand at room temperature for 6 days, re-dispersed at 120 rpm for 1 minute, and the second turbidity of the aqueous dispersion is measured.

[0013] 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

[0014] In an embodiment, the second turbidity change rate of the fiber-reinforced material measured by the following method can be less than 20%:

[0015] [Measurement method]

[0016] 1) The aqueous dispersion is left to stand for 1 hour, re-dispersed at 120 rpm for 1 minute, and then the initial turbidity of the aqueous dispersion is measured.

[0017] 2) The second turbidity change rate is a value obtained by dividing the difference between the first turbidity and the initial turbidity by the first turbidity.

[0018] In an embodiment, the fiber-reinforced material can be in an elongated shape, have a diameter of 1 nm to 20 nm, and have a length of 30 nm to 500 nm.

[0019] In an embodiment, the fiber-reinforced material can contain sulfur in an amount of 0.5 wt% to 1.5 wt%.

[0020] In an embodiment, the fiber-reinforced material can contain a surface treatment agent including a sulfate or a carboxylate, and the content of the surface treatment agent can be 0.1 mol / kg to 0.5 mol / kg.

[0021] In an embodiment, the zeta potential of the fiber-reinforced material can be -60 mV to -25 mV.

[0022] In an embodiment, the glass transition temperature of the fiber-reinforced material can be 80℃ to 100℃.

[0023] In an embodiment, the thermal decomposition onset temperature of the fiber-reinforced material can be 200℃ to 240℃, and the maximum thermal decomposition temperature of the fiber-reinforced material can be 300℃ to 360℃.

[0024] In an embodiment, the fiber-reinforced material can contain an alkali metal.

[0025] In an embodiment, the fiber-reinforced material can contain a sulfate in an amount of 0.1 mol / kg to 0.5 mol / kg.

[0026] In an embodiment, the hydroxyl-based carboxyl intensity of the fiber-reinforced material measured by the following method can be 0.2 to 0.8:

[0027] [Measurement method]

[0028] 1) An infrared absorption spectrum of an aqueous dispersion of the fiber-reinforced material is obtained using infrared spectroscopy.

[0029] 2) From the infrared absorption spectrum, a first peak is obtained at a wave number of 2782 cm -1 to 2991 cm -1 and a second peak is obtained at a wave number of 1531 cm -1 to 1769 cm -1 .

[0030] 3) The carboxyl intensity is a value obtained by dividing the maximum absorbance of the second peak by the maximum absorbance of the first peak.

[0031] According to another aspect of the present application, there is provided a biodegradable film composition comprising: a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a fiber-reinforced material, wherein a first turbidity change rate of the fiber-reinforced material measured by the following method is less than 15%:

[0032] [Measurement method]

[0033] 1) The fiber-reinforced material is dispersed in water at a concentration of 1 wt% at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber-reinforced material.

[0034] 2) The aqueous dispersion is left to stand at room temperature for 2 days, re-dispersed at 120 rpm for 1 minute, and a first turbidity of the aqueous dispersion is measured.

[0035] 3) The aqueous dispersion is left to stand at room temperature for 6 days, re-dispersed at 120 rpm for 1 minute, and a second turbidity of the aqueous dispersion is measured.

[0036] 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

[0037] According to still another aspect of the present application, there is provided a biodegradable molded article comprising a biodegradable polyester resin composition comprising: a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a fiber-reinforced material, wherein a first turbidity change rate of the fiber-reinforced material measured by the following method is less than 15%:

[0038] [Measurement method]

[0039] 1) Disperse the fiber-reinforced material in water at a concentration of 1 wt% at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber-reinforced material.

[0040] 2) Let the aqueous dispersion stand at room temperature for 2 days, re-disperse at 120 rpm for 1 minute, and measure the first turbidity of the aqueous dispersion.

[0041] 3) Let the aqueous dispersion stand at room temperature for 6 days, re-disperse at 120 rpm for 1 minute, and measure the second turbidity of the aqueous dispersion.

[0042] 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

[0043] Advantageous effects

[0044] The biodegradable polyester resin composition according to the embodiment includes: a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and a fiber-reinforced material having a low turbidity change rate.

[0045] The fiber-reinforced material can have high dispersibility and low agglomeration with respect to the diol. Accordingly, the fiber-reinforced material can be uniformly dispersed in the diol without agglomeration, and thus can be introduced into a process of producing the polyester resin.

[0046] As a result, the fiber-reinforced material can be uniformly dispersed in the biodegradable polyester resin composition according to the embodiment.

[0047] The fiber-reinforced material has high electrical conductivity. In addition, the fiber-reinforced material can have a suitable aspect ratio. The fiber-reinforced material can include an appropriate amount of a sulfate or a carboxylate. In addition, the fiber-reinforced material can have a suitable zeta potential. In addition, the fiber-reinforced material can have a suitable glass transition temperature. In addition, the fiber-reinforced material can have a suitable thermal decomposition onset temperature. In addition, the fiber-reinforced material can have a suitable maximum thermal decomposition temperature.

[0048] Accordingly, the biodegradable polyester resin composition according to the embodiment can have improved mechanical properties, improved thermal properties, improved optical properties, and improved electrical properties.

[0049] The biodegradable polyester resin composition according to the embodiment can maintain a certain level or higher of mechanical properties and chemical properties during use by a user.

[0050] Accordingly, the biodegradable film and the biodegradable molded article according to the embodiment can have improved properties as described above. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1FIGS. 1 to 3 are diagrams illustrating an apparatus for producing a polyester resin composition according to embodiments, for illustrative purposes; and

[0052] Figure 2 Embodiments of a biodegradable molded article formed of a polyester resin composition according to embodiments are illustrated. DETAILED DESCRIPTION

[0053] Hereinafter, the present application will be described in greater detail with reference to the following embodiments. The scope of the present application is not limited to the following embodiments, and encompasses modifications substantially equivalent to the technical spirit thereof.

[0054] In the present specification, when a certain part "comprises" a certain component, unless otherwise specified, it means that the part can further include another component, rather than excluding another component.

[0055] Further, it should be understood that all numerical ranges described in the present specification for representative physical property values, dimensions, etc. of components described therein are modified by the term "about" unless otherwise indicated.

[0056] In the present specification, terms such as first, second, primary, and secondary are used to describe various components, and the components are not limited by the terms. The terms are used only to distinguish one component from another component.

[0057] The biodegradable polyester resin composition according to embodiments includes a biodegradable polyester resin. The biodegradable polyester resin composition according to embodiments can include a biodegradable polyester resin alone or together with other resins or additives.

[0058] The biodegradable polyester resin includes a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The biodegradable polyester resin includes a diol residue, an aromatic dicarboxylic acid residue, and an aliphatic dicarboxylic acid residue. The diol residue is derived from a diol, the aromatic dicarboxylic acid residue is derived from an aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid residue is derived from an aliphatic dicarboxylic acid. The biodegradable polyester resin includes a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component. Likewise, the diol component can be derived from a diol, the aromatic dicarboxylic acid component can be derived from an aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid component can be derived from an aliphatic dicarboxylic acid.

[0059] In the description of the biodegradable polyester resin composition according to embodiments, a diol residue can be expressed as a diol. In the biodegradable polyester resin, a dicarboxylic acid residue can be expressed as a dicarboxylic acid. Further, a residue can be expressed as a component.

[0060] The diol can be an aliphatic diol. The diol can be a biologically derived diol. The diol can be at least one selected from the group consisting of ethylene glycol, 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.

[0061] The diol can be at least one selected from the group consisting of 1,4-butanediol, 1,2- ethanediol, 1,3-propanediol, diethylene glycol, and neopentyl glycol, or derivatives thereof.

[0062] The diol can be at least one selected from the group consisting of 1,4-butanediol, 1,2- ethanediol, 1,3-propanediol, or derivatives thereof.

[0063] The diol can comprise 1,4-butanediol, or derivatives thereof.

[0064] The diol can be derived from biomass.

[0065] The aromatic dicarboxylic acid can be at least one selected from the group consisting of phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5- naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, or derivatives thereof.

[0066] The aromatic dicarboxylic acid can be at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, 2,6-naphthalene dicarboxylic acid, isophthalic acid, or derivatives thereof.

[0067] The aromatic dicarboxylic acid can comprise terephthalic acid, dimethyl terephthalate, or derivatives thereof.

[0068] The aliphatic dicarboxylic acid can 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, serveric acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and 1,4- cyclohexane dicarboxylic acid, or derivatives thereof.

[0069] The aliphatic dicarboxylic acid can be at least one selected from the group consisting of adipic acid, succinic acid, and sebacic acid, or a derivative thereof.

[0070] The aliphatic dicarboxylic acid can comprise adipic acid or a derivative thereof.

[0071] In the biodegradable polyester resin, the mole ratio of all diol residues including the diol to all dicarboxylic acid residues including the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid can be about 1 :0.9 to about 1 :1.1. The mole ratio of all diol residues to all dicarboxylic acid residues can be about 1 :0.95 to about 1 :1.05.

[0072] In the biodegradable polyester resin, the mole ratio of the aromatic dicarboxylic acid residues to the aliphatic dicarboxylic acid residues can be about 3:7 to about 7:3. In the biodegradable polyester resin, the mole ratio of the aromatic dicarboxylic acid residues to the aliphatic dicarboxylic acid residues can be about 3.3:6.7 to about 6.7:3.3. In the biodegradable polyester resin, the mole ratio of the aromatic dicarboxylic acid residues to the aliphatic dicarboxylic acid residues can be about 4:6 to about 6:4. In the biodegradable polyester resin, the mole ratio of the aromatic dicarboxylic acid residues to the aliphatic dicarboxylic acid residues can be about 4.2:5.8 to about 5:5.

[0073] The biodegradable polyester resin can comprise about 90 mol% or more of diol residues derived from 1,4-butanediol based on the total diol content. The biodegradable polyester resin can comprise about 95 mol% or more of diol residues derived from 1,4-butanediol based on the total diol content. The biodegradable polyester resin can comprise about 98 mol% or more of diol residues derived from 1,4-butanediol based on the total diol content.

[0074] The biodegradable polyester resin can comprise about 30 mol% to about 70 mol% of aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate based on the total dicarboxylic acid content. The biodegradable polyester resin can comprise about 35 mol% to about 65 mol% of aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate based on the total dicarboxylic acid content. The biodegradable polyester resin can comprise about 40 mol% to about 59 mol% of dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate based on the total dicarboxylic acid content. The biodegradable polyester resin can comprise about 43 mol% to about 53 mol% of aromatic dicarboxylic acid residues derived from terephthalic acid or dimethyl terephthalate based on the total dicarboxylic acid content.

[0075] The biodegradable polyester resin can include about 30 mol% to about 70 mol% of aliphatic dicarboxylic acid residues derived from adipic acid based on the total dicarboxylic acid content. The biodegradable polyester resin can include about 35 mol% to about 65 mol% of aliphatic dicarboxylic acid residues derived from adipic acid based on the total dicarboxylic acid content. The biodegradable polyester resin can include about 41 mol% to about 60 mol% of aliphatic dicarboxylic acid residues derived from adipic acid based on the total dicarboxylic acid content. The biodegradable polyester resin can include about 47 mol% to about 57 mol% of aliphatic dicarboxylic acid residues derived from adipic acid based on the total dicarboxylic acid content.

[0076] Further, the biodegradable polyester resin can include at least one first block and at least one second block. The biodegradable polyester resin can have a molecular structure in which the first block and the second block are alternately bonded.

[0077] The first block can include diol residues and aromatic dicarboxylic acid residues. The first block can be formed by esterification of a diol and an aromatic dicarboxylic acid. The first block can include only diol residues and aromatic dicarboxylic acid residues. The first block can include only repeating units formed by esterification of a diol and an aromatic dicarboxylic acid. That is, the first block can represent the sum of repeating units of a diol and an aromatic dicarboxylic acid before being combined with an aliphatic dicarboxylic acid.

[0078] The second block can include diol residues and aliphatic dicarboxylic acid residues. The second block can be formed by esterification of a diol and an aliphatic dicarboxylic acid. The second block can include only diol residues and aliphatic dicarboxylic acid residues. The second block can include only repeating units formed by esterification of a diol and an aliphatic dicarboxylic acid. That is, the second block can represent the sum of repeating units of a diol and an aliphatic dicarboxylic acid before being combined with an aromatic dicarboxylic acid.

[0079] In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first block to the number (Y) of the second block can be about 0.5 to about 1.5. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first block to the number (Y) of the second block can be about 0.6 to about 1.4. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first block to the number (Y) of the second block can be about 0.7 to about 1.3. In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first block to the number (Y) of the second block can be about 0.75 to about 1.2. Further, in the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first block to the number (Y) of the second block can be 0.8 to 1. The number of the first block can be less than the number of the second block.

[0080] The number of the first blocks can be about 30 to about 300. The number of the first blocks can be about 40 to about 250. The number of the first blocks can be about 50 to about 220. The number of the first blocks can be about 60 to about 200. The number of the first blocks can be about 70 to about 200. The number of the first blocks can be about 75 to about 200.

[0081] The number of the first blocks can vary depending on the content of the aromatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the alternating ratio described below. That is, the number of the first blocks can increase as the molar ratio of the aromatic dicarboxylic acid increases, the molecular weight of the biodegradable polyester resin increases, and the alternating ratio described below increases.

[0082] The number of the second blocks can be about 30 to about 300. The number of the second blocks can be about 40 to about 250. The number of the second blocks can be about 50 to about 220. The number of the second blocks can be about 60 to about 200. The number of the second blocks can be about 70 to about 200. The number of the second blocks can be about 75 to about 200.

[0083] The number of the second blocks can vary depending on the content of the aliphatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the polymerization process described below. That is, the number of the first blocks can increase as the molar ratio of the aliphatic dicarboxylic acid increases and the molecular weight of the biodegradable polyester resin increases.

[0084] When the biodegradable polyester resin includes the first blocks and the second blocks within the ranges, the biodegradable polyester resin composition according to the embodiments can have appropriate biodegradability while having appropriate mechanical strength. In addition, when the biodegradable polyester resin includes the first blocks and the second blocks within the ranges, the biodegradable polyester resin composition according to the embodiments can have improved rigidity while having improved flexibility. Accordingly, the biodegradable polyester resin composition according to the embodiments can be used for injection-molded articles or the like. In addition, when the biodegradable polyester resin includes the first blocks and the second blocks within the ranges, the biodegradable polyester resin composition according to the embodiments can have appropriate biodegradability while having appropriate ultraviolet light durability or the like.

[0085] The first block can be represented by the following Formula 1:

[0086] [Formula 1]

[0087]

[0088] wherein 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 is 1 to 20.

[0089] R1may be a substituted or unsubstituted phenylene group, and R2may be a butylene group.

[0090] The second block can be represented by the following Formula 2:

[0091] [Formula 2]

[0092]

[0093] wherein R3and R4are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n is 1 to 20.

[0094] R3and R4may be a butylene group.

[0095] The biodegradable polyester resin can have a structure in which the first block and the second block are alternately bonded to each other. The biodegradable polyester resin can be represented by the following Formula 3.

[0096] [Formula 3]

[0097]

[0098] wherein R1is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, R2is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and m is 1 to 20. In addition, R3and R4are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n is 1 to 20.

[0099] The diol residue can include a residue of 1,4-butanediol or a derivative thereof, the aromatic dicarboxylic acid residue can include a residue of terephthalic acid or a derivative thereof, and the aliphatic dicarboxylic acid residue can include a residue of adipic acid or a derivative thereof.

[0100] For example, the biodegradable polyester resin can include a first block including a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof.

[0101] Alternatively, the biodegradable polyester resin can include a first block including a residue of 1,4-butanediol or a derivative thereof and a residue of dimethyl terephthalate or a derivative thereof.

[0102] The biodegradable polyester resin can include a second block including a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

[0103] Alternatively, the biodegradable polyester resin can include a second block including a residue of 1,4-butanediol or a derivative thereof and a residue of succinic acid or a derivative thereof.

[0104] The biodegradable polyester resin according to the embodiment of the present application can include a first block including residues of 1,4-butanediol or a derivative thereof and residues of terephthalic acid or a derivative thereof, and a second block including residues of 1,4-butanediol or a derivative thereof and residues of adipic acid or a derivative thereof.

[0105] The first block can be represented by the following Formula 4, and the second block can be represented by the following Formula 5.

[0106] [Formula 4]

[0107]

[0108] wherein m is 1 to 20.

[0109] [Formula 5]

[0110]

[0111] wherein n is 1 to 20.

[0112] The biodegradable polyester resin can be represented by the following Formula 6.

[0113] [Formula 6]

[0114]

[0115] wherein m is 1 to 20, and n is 1 to 20.

[0116] When the first block and the second block satisfy the constitution, the biodegradable polyester sheet, film, or molded article having excellent biodegradability and water degradability and improved properties can be more advantageously provided.

[0117] Further, when the biodegradable polyester resin includes the first block and the second block within the range, the biodegradable polyester resin composition according to the embodiment can have appropriate mechanical properties and appropriate UV resistance.

[0118] The mechanical properties of the biodegradable polyester resin composition according to the embodiment can be improved due to the first block and the second block having the above-described properties.

[0119] The biodegradable polyester resin composition according to the embodiment can have appropriate UV resistance due to the first block and the second block having the above-described properties.

[0120] The biodegradable polyester resin composition according to the embodiment can have an appropriate biodegradation rate due to the first block and the second block having the above-described properties.

[0121] Due to the first block and the second block having the above-described properties, the biodegradable polyester resin composition according to the embodiments can have an appropriate hydrolysis rate.

[0122] The biodegradable polyester resin can further include a branching agent. The branching agent can include at least one selected from the group consisting of a tri- or higher alcohol, an acid anhydride, and a tri- or higher carboxylic acid. The branching agent can react with a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. Accordingly, the branching agent can be a part of the molecular structure of the biodegradable polyester resin.

[0123] The tri- or higher alcohol can be at least one selected from the group consisting of glycerol, pentaerythritol, or trimethylolpropane.

[0124] The tri- or higher carboxylic acid can be at least one selected from the group consisting of methane tricarboxylic acid, ethane tricarboxylic acid, citric acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzene tricarboxylic 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, and benzene-1,2,4,5-tetracarboxylic acid.

[0125] The branching agent can be included in the biodegradable polyester resin at a content of about 0.03 wt% to about 5 wt% based on the total amount of the biodegradable polyester resin. The branching agent can be included in the biodegradable polyester resin at a content of about 0.04 wt% to about 3 wt% based on the total amount of the biodegradable polyester resin. The branching agent can be included in the biodegradable polyester resin at a content of about 0.05 wt% to about 1 wt% based on the total amount of the biodegradable polyester resin.

[0126] Due to the biodegradable polyester resin including the branching agent in the above-described range, the biodegradable polyester resin composition according to the embodiments can have appropriate mechanical properties and appropriate biodegradability.

[0127] The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 30 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 50 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 70 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 80 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 90 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 95 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 99 wt% or more, based on the total weight of the composition. The biodegradable polyester resin composition according to embodiments can include a biodegradable resin in a content of about 100 wt% or less, based on the total weight of the composition.

[0128] The biodegradable polyester resin composition according to embodiments can further include a reinforcing material. The reinforcing material can improve the mechanical properties of the biodegradable polyester resin composition according to embodiments and the mechanical properties of a film or a molded article made of the composition. In addition, the reinforcing material can control the deformation properties of the biodegradable polyester resin composition according to embodiments due to ultraviolet rays. In addition, the reinforcing material can control the hydrolysis properties of the biodegradable polyester resin composition according to embodiments. In addition, the reinforcing material can control the biodegradability of the biodegradable polyester resin according to embodiments.

[0129] The reinforcing material can be a fiber derived from biomass. The reinforcing material can be a fiber made of an organic material. The reinforcing material can be nanocellulose.

[0130] The nanocellulose can be one or more selected from the group consisting of nanocrystalline cellulose, cellulose nanofiber, microfibrillated cellulose, methylol cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, pentyl cellulose, hexyl cellulose, and cyclohexyl cellulose.

[0131] The nanocellulose can comprise an ionically bonded metal. The nanocellulose can comprise an alkali metal. The nanocrystalline cellulose can comprise elemental sodium. Further, the nanocrystalline cellulose can comprise a sulfate salt. The nanocrystalline cellulose can comprise a carboxylate salt. The nanocrystalline cellulose can include cellulose sodium bisulfate salt (cellulose sodium bisulfate salt).

[0132] The nanocellulose can be represented by the following Formula 7:

[0133] [Formula 7]

[0134] [(C6H 10 O5) x SO3Na] y

[0135] wherein x is 1 to 35, and y is 1 to 10. x can be 15 to 35, and y can be 1 to 10.

[0136] The specific surface area of the nanocellulose can be about 200 m 2 / g to about 600 m 2 / g. The specific surface area of the nanocellulose can be about 250 m 2 / g to about 500 m 2 / g.

[0137] The weight average molecular weight of the nanocellulose can be about 10000 g / mol to about 70000 g / mol. The weight average molecular weight of the nanocrystalline cellulose can be about 11000 g / mol to about 60000 g / mol.

[0138] The moisture content of the nanocrystalline cellulose can be about 2 wt% to about 8 wt%. The moisture content of the nanocrystalline cellulose can be about 4 wt% to about 6 wt%.

[0139] The average diameter of the nanocellulose can be about 0.5 nm to about 20 nm. The average diameter of the nanocellulose can be about 1 nm to about 15 nm. The average diameter of the nanocellulose can be about 1.5 nm to about 12 nm. The average diameter of the nanocellulose can be about 2 nm to about 11 nm.

[0140] The average length of the nanocellulose can be about 20 nm to about 300 nm. The average length of the nanocellulose can be about 30 nm to about 500 nm. The average length of the nanocellulose can be about 30 nm to about 180 nm. The average length of the nanocellulose can be about 35 nm to about 150 nm. The average length of the nanocellulose can be about 100 nm to about 300 nm.

[0141] The aspect ratio (average length / average diameter) of the nanocellulose can be about 10 to about 50. The aspect ratio of the nanocellulose can be about 20 to about 40. The aspect ratio of the nanocellulose can be about 25 to about 35.

[0142] Due to the nanocellulose having the average diameter, the average length, and the aspect ratio described above, the mechanical properties of the biodegradable resin composition according to the embodiments can be effectively enhanced.

[0143] In particular, when the diameter and the length of the nanocellulose satisfy the ranges described above, the biodegradability and the properties of the biodegradable resin or the biodegradable polyester sheet, film, and molded article obtained using the first biodegradable resin can be further improved.

[0144] The diameter and the length of the nanocellulose can be measured by an atomic force microscope in a state dispersed in water.

[0145] The content of sulfur in the nanocellulose can be about 0.05 wt% to about 1.2 wt% based on the total amount of the nanocellulose. The content of sulfur in the nanocellulose can be about 0.1 wt% to about 1.1 wt% based on the total amount of the nanocellulose. The content of sulfur in the nanocellulose can be about 0.5 wt% to about 1.5 wt% based on the total amount of the nanocellulose.

[0146] The content of sulfur in the nanocellulose can be measured according to ASTM D2622.

[0147] The nanocellulose can include a surface treatment agent. The surface treatment agent can include at least one selected from the group consisting of a sulfate and a carboxylate. That is, the nanocellulose can be surface-treated with a sulfate or a carboxylate.

[0148] The content of the surface treatment agent can be about 0.05 mol / kg to about 1 mol / kg. The content of the surface treatment agent can be about 0.1 mol / kg to about 0.5 mol / kg. The content of the surface treatment agent can be about 0.2 mol / kg to about 0.4 mol / kg.

[0149] The nanocellulose can include a sulfate in a content of about 0.05 mol / kg to about 1 mol / kg. The nanocellulose can include a sulfate in a content of about 0.1 mol / kg to about 0.5 mol / kg. The nanocellulose can include a sulfate in a content of about 0.15 mol / kg to about 0.4 mol / kg. The nanocellulose can include a sulfate in a content of about 0.2 mol / kg to about 0.3 mol / kg.

[0150] The content of the sulfate can be measured by Fourier transform infrared spectroscopy (FTIR).

[0151] The nanocellulose can comprise carboxylate salt in an amount of about 0.05 mol / kg to about 1 mol / kg. The nanocellulose can comprise carboxylate salt in an amount of about 0.1 mol / kg to about 0.5 mol / kg. The nanocellulose can comprise carboxylate salt in an amount of about 0.1 mol / kg to about 0.4 mol / kg. The nanocellulose can comprise carboxylate salt in an amount of about 0.1 mol / kg to about 0.3 mol / kg.

[0152] The amount of carboxylate salt can be measured by FTIR.

[0153] The nanocellulose can have a hydroxyl-based carboxyl intensity.

[0154] The hydroxyl-based carboxyl intensity can be measured by Measurement Method 2 as follows:

[0155] [Measurement Method 2]

[0156] 1) Disperse the nanocellulose in water at a concentration of about 1 wt% to obtain an aqueous dispersion of the nanocellulose.

[0157] 2) Obtain an infrared absorption spectrum of the aqueous dispersion of the nanocellulose by infrared spectroscopy.

[0158] 3) In the infrared absorption spectrum, obtain a first peak at a wave number of 2782 cm -1 to 2991 cm -1 and a second peak at a wave number of 1531 cm -1 to 1769 cm -1 .

[0159] 4) The hydroxyl-based carboxyl intensity is a value obtained by dividing the maximum absorbance of the second peak by the maximum absorbance of the first peak.

[0160] The infrared absorption spectrum can be measured by an infrared spectrometer (Fourier transform infrared spectrometer). The infrared spectrometer can be selected from the group consisting of Spectrum 2, Spectrum 3, or Spotlight 200i / 400i by PerkinElmer.

[0161] The hydroxyl-based carboxyl intensity can be 0.2 to 0.8. The hydroxyl-based carboxyl intensity can be 0.25 to 0.75. The hydroxyl-based carboxyl intensity can be 0.2 to 0.6. The hydroxyl-based carboxyl intensity can be 0.5 to 0.8.

[0162] Since the nanocellulose has a hydroxyl strength based on hydroxyl within the above range, it can have a proper content of hydroxyl and carboxyl groups. Thus, the nanocellulose can be uniformly dispersed in the biodegradable resin composition according to the embodiment and have a strong binding force with the polymer contained in the biodegradable resin. As a result, the nanocellulose can improve the mechanical properties of the biodegradable resin composition according to the embodiment.

[0163] The pH of the nanocellulose can be 5 to 7. The pH of the nanocellulose can be 6 to 7. The pH of the nanocellulose can be 5 to 8.

[0164] The zeta potential of the nanocellulose can be about -60 mV to about -20 mV. The zeta potential of the nanocellulose can be about -50 mV to about -25 mV. The zeta potential of the nanocellulose can be about -45 mV to about -30 mV. The zeta potential of the nanocellulose can be about -60 mV to about -25 mV. The zeta potential of the nanocellulose can be about -55 mV to about -30 mV.

[0165] The zeta potential of the cellulose can be measured with a zeta potential meter (e.g., Zetasizer Nano ZS, Malvern).

[0166] Since the nanocellulose has a sulfur, sulfate, carboxylate, pH value, and zeta potential within the above range, it can exhibit improved dispersibility in water or alcohol, etc.

[0167] The conductivity of the nanocellulose can be about 50 µS / cm to about 2000 µS / cm. The conductivity of the nanocellulose can be about 100 µS / cm to about 1000 µS / cm. The conductivity of the nanocellulose can be about 150 µS / cm to about 1000 µS / cm. The conductivity of the nanocellulose can be about 200 µS / cm to about 1000 µS / cm.

[0168] The conductivity can be measured by a pH meter when the nanocellulose is dispersed in water at a concentration of about 2 wt%.

[0169] Since the nanocellulose has a conductivity within the above range, the biodegradable polyester resin composition according to the embodiment can exhibit improved electrical properties.

[0170] The glass transition temperature of the nanocellulose can be about 70℃ to about 110℃. The glass transition temperature of the nanocellulose can be about 80℃ to about 100℃. The glass transition temperature of the nanocellulose can be about 85℃ to about 95℃. The glass transition temperature of the nanocellulose can be about 80℃ to about 95℃. The glass transition temperature of the nanocellulose can be about 85℃ to about 100℃.

[0171] The glass transition temperature can be measured by a differential scanning calorimeter.

[0172] The thermal decomposition onset temperature of the nanocellulose can be about 190°C to about 250°C. The thermal decomposition onset temperature of the nanocellulose can be about 200°C to about 240°C. The thermal decomposition onset temperature of the nanocellulose can be about 210°C to about 230°C. The thermal decomposition onset temperature of the nanocellulose can be about 210°C to about 250°C.

[0173] The maximum thermal decomposition temperature of the nanocellulose can be about 290°C to about 380°C. The maximum thermal decomposition temperature of the nanocellulose can be about 300°C to about 360°C. The maximum thermal decomposition temperature of the nanocellulose can be about 310°C to about 360°C. The maximum thermal decomposition temperature of the nanocellulose can be about 315°C to about 360°C. The maximum thermal decomposition temperature of the nanocellulose can be about 320°C to about 360°C.

[0174] The thermal decomposition onset temperature and the maximum thermal decomposition temperature can be measured by a thermogravimetric analyzer.

[0175] A nanocrystalline cellulose sample was put into a thermogravimetric analyzer (TGA Q500 V20, TA Instruments) and heated at a rate of about 10°C / min from about 150°C to about 600°C under a nitrogen atmosphere. Here, the thermal decomposition onset temperature can be a temperature at which thermal decomposition starts after the weight of the sample is reduced by about 4 wt%. In addition, the maximum thermal decomposition temperature can be a temperature at which the rate of weight loss of the sample is the greatest with respect to temperature.

[0176] Since the glass transition temperature, the thermal decomposition onset temperature, and the maximum thermal decomposition temperature of the nanocellulose are within the above ranges, the biodegradable polyester resin composition according to the embodiments can exhibit improved heat resistance.

[0177] In addition, since the nanocellulose has improved heat resistance as described above, the formation of carbonized materials can be prevented during the production of the biodegradable polyester resin composition according to the embodiments.

[0178] Accordingly, the biodegradable polyester resin composition according to the embodiments can have improved appearance.

[0179] The nanocellulose can have a first turbidity change rate.

[0180] The turbidity of the nanocellulose can be measured by the following method.

[0181] First, the nanocellulose is dispersed in water to obtain an aqueous dispersion. The aqueous dispersion can include nanocellulose at a concentration of about 1 wt%. The aqueous dispersion can include nanocellulose at a concentration of about 0.5 wt%. The aqueous dispersion can include nanocellulose at a concentration of about 1.5 wt%.

[0182] The water and the nanocellulose can be mixed sufficiently to make the aqueous dispersion. The nanocellulose and the water can be dispersed at a speed of about 1000 rpm for about 30 minutes or more to make the aqueous dispersion.

[0183] The nanocellulose can be dispersed in water at a concentration of about 1 wt% at a speed of about 1000 rpm for about 30 minutes to obtain the aqueous dispersion of nanocellulose.

[0184] Next, the aqueous dispersion can be stabilized for about 1 hour, then re-dispersed at a speed of about 120 rpm for about 1 minute, and the initial turbidity of the aqueous dispersion can be measured.

[0185] Further, the aqueous dispersion can be left at room temperature for about 2 days, re-dispersed at a speed of about 120 rpm for about 1 minute, and the first turbidity of the aqueous dispersion can be measured.

[0186] Further, the aqueous dispersion can be left at room temperature for about 4 days, re-dispersed at a speed of about 120 rpm for about 1 minute, and the third turbidity of the aqueous dispersion can be measured.

[0187] Further, the aqueous dispersion can be left at room temperature for about 6 days, re-dispersed at a speed of about 120 rpm for about 1 minute, and the second turbidity of the aqueous dispersion can be measured.

[0188] The nanocellulose can have a first turbidity change rate.

[0189] The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

[0190] The first turbidity change rate can be derived according to Equation 1 below:

[0191] [Equation 1]

[0192] The first turbidity change rate = |second turbidity - first turbidity| / first turbidity

[0193] The first turbidity change rate can be less than about 20%. The first turbidity change rate can be less than about 10%. The first turbidity change rate can be less than about 15%. The first turbidity change rate can be less than about 7%. The first turbidity change rate can be less than about 5%.

[0194] The fiber-reinforced material can have a second turbidity change rate.

[0195] The second turbidity change rate is a value obtained by dividing the difference between the first turbidity and the initial turbidity by the first turbidity.

[0196] The second turbidity change rate can be derived by Equation 2 below:

[0197] [Equation 2]

[0198] The second turbidity change rate = |initial turbidity - first turbidity| / first turbidity

[0199] The second turbidity change rate can be less than about 20%. The second turbidity change rate can be less than about 25%. The second turbidity change rate can be less than about 17%. The second turbidity change rate can be less than about 15%.

[0200] The first turbidity can be about 100 NTU to about 300 NTU. The first turbidity can be about 120 NTU to about 270 NTU. The first turbidity can be about 70 NTU to about 110 NTU. The first turbidity can be about 80 NTU to about 100 NTU.

[0201] The second turbidity can be about 95 NTU to about 295 NTU. The second turbidity can be about 115 NTU to about 265 NTU. The second turbidity can be about 70 NTU to about 110 NTU. The second turbidity can be about 77 NTU to about 97 NTU.

[0202] The third turbidity can be about 95 NTU to about 295 NTU. The third turbidity can be about 115 NTU to about 265 NTU. The third turbidity can be about 70 NTU to about 110 NTU. The third turbidity can be about 77 NTU to about 97 NTU.

[0203] The initial turbidity can be about 230 NTU to about 350 NTU. The initial turbidity can be about 90 NTU to about 115 NTU. The initial turbidity can be about 450 NTU to about 550 NTU.

[0204] The turbidity of the aqueous dispersion can be measured with a turbidimeter. The turbidity of the aqueous dispersion can be measured by a scattered light measurement method.

[0205] When a sample containing a turbidity substance is present at a turbidity detector having a calibrated optical system at a light receiving unit placed at a 90° angle to a light source unit, scattered light proportional to the turbidity is generated. By measuring this scattered light, the turbidity can be sensitively detected, particularly at a low concentration.

[0206] The scattered light measurement method can measure the scattered light at a 90° angle by irradiating light to one side of the aqueous dispersion, in which the light is scattered upon colliding with particles in the liquid.

[0207] Since the fiber-reinforced material has the haze and the haze variation rate within the above-described range, it exhibits improved dispersibility and lower agglomeration. In addition, since the fiber-reinforced material has the haze variation rate within the above-described range, it can maintain the improved dispersibility and the lower agglomeration for a longer period of time.

[0208] The nanocellulose can be included in the biodegradable polyester resin composition according to the embodiment in a content of about 0.01 parts by weight to about 2 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose can be included in the biodegradable polyester resin composition according to the embodiment in a content of about 0.03 parts by weight to about 1.5 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose can be included in the biodegradable polyester resin composition according to the embodiment in a content of about 0.04 parts by weight to about 1.2 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The nanocellulose can be included in the biodegradable polyester resin composition according to the embodiment in a content of about 0.05 parts by weight to about 1 part by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0209] Since the nanocellulose has the above-described characteristics, it can be uniformly dispersed in the biodegradable polyester resin composition according to the embodiment.

[0210] Since the nanocellulose has the above-described characteristics, it can improve the mechanical properties of the biodegradable polyester resin composition according to the embodiment.

[0211] In addition, the nanocellulose can act as a nucleating agent, thereby being able to improve the crystallization rate of the biodegradable polyester resin composition according to the embodiment. Accordingly, the nanocellulose can increase the crystallization temperature of the biodegradable polyester resin composition according to the embodiment.

[0212] Since the nanocellulose has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have appropriate UV resistance.

[0213] Since the nanocellulose has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have an appropriate biodegradation rate.

[0214] Since the nanocellulose has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have an appropriate hydrolysis rate.

[0215] The biodegradable polyester resin composition according to the embodiment can include a metal salt.

[0216] The metal salt can 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 embodiments. The metal salt can 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 embodiments. The metal salt can 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 embodiments. The metal salt can 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 embodiments.

[0217] The metal salt can be at least one selected from the group consisting of a nitrate, a sulfate, a hydrochloride, a carboxylate, and the like. The metal salt can be at least one selected from the group consisting of a titanium salt, a silicon salt, a sodium salt, a calcium salt, a potassium salt, a magnesium salt, a copper salt, an iron salt, an aluminum salt, a silver salt, and the like. The metal salt can be at least one selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, sodium nitrate, and the like.

[0218] The metal salt can include 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).

[0219] Further, the metal salt can be selected from the group consisting of acetate, nitrate, nitride, sulfide, sulfate, sulfoxide, hydroxide, hydrate, chloride, chlorate, and bromide.

[0220] Since the biodegradable polyester resin composition according to the embodiments contains the metal salt in the above-described amount, the hydrolysis rate and the biodegradation rate can be appropriately controlled.

[0221] The biodegradable polyester resin composition according to the embodiments can further include an anti-hydrolysis agent.

[0222] The anti-hydrolysis agent can be at least one selected from silicon-based compounds such as silane, silazane, and siloxane.

[0223] The anti-hydrolysis agent can include an alkoxysilane. The anti-hydrolysis agent can include trimethoxysilane and / or triethoxysilane. The anti-hydrolysis agent can include an alkoxysilane containing an epoxy group. The anti-hydrolysis agent can include at least one selected from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, and 3-glycidyloxypropyltriethoxysilane.

[0224] The anti-hydrolysis agent can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 1 ppm to about 10,000 ppm. The anti-hydrolysis agent can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 1 ppm to about 1,000 ppm. The anti-hydrolysis agent can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 5 ppm to 500 ppm. The anti-hydrolysis agent can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 10 ppm to 300 ppm.

[0225] The anti-hydrolysis agent can be bonded to the biodegradable polyester resin. The anti-hydrolysis agent can be chemically bonded to the biodegradable polyester resin. The anti-hydrolysis agent can be chemically bonded to the polymer contained in the biodegradable polyester resin. The anti-hydrolysis agent can be coupled to the polymer contained in the biodegradable polyester resin.

[0226] Since the biodegradable polyester resin composition according to the embodiments contains the anti-hydrolysis agent in the above range, it can have appropriate hydrolysis resistance. In particular, since the biodegradable polyester resin according to the embodiments contains the anti-hydrolysis agent in the range, it can have appropriate initial hydrolysis characteristics and improved biodegradability.

[0227] Accordingly, the biodegradable polyester resin composition according to the embodiments can contain a silicon element. The biodegradable polyester resin composition according to the embodiments can contain a silicon element in a content of about 0.1 ppm to about 100 ppm. The biodegradable polyester resin composition according to the embodiments can contain a silicon element in a content of about 0.1 ppm to about 50 ppm. The biodegradable polyester resin composition according to the embodiments can contain a silicon element in a content of about 0.1 ppm to about 20 ppm.

[0228] In addition, the anti-hydrolysis agent can also react with a terminal carboxyl group or an unreacted carboxyl group. Accordingly, the biodegradable polyester resin composition according to the embodiments can have a lower acid value.

[0229] In addition, the anti-hydrolysis agent can be coupled to the polymer contained in the biodegradable polyester resin, so that the biodegradable polyester resin composition according to the embodiments can increase the ratio of high molecular weight polymers. Accordingly, the mechanical properties of the biodegradable polyester resin composition according to the embodiments can be improved.

[0230] The biodegradable polyester resin composition according to the embodiments can further contain a chain extender.

[0231] The chain extender can contain an isocyanate.

[0232] The chain extender can be at least one selected from the group consisting of monofunctional isocyanate or polyfunctional isocyanate.

[0233] The chain extender can be at least one selected from the group consisting of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate and diphenylmethane-2,4'-diisocyanate, naphthalene-1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and methylene bis(4-isocyanatocyclohexane).

[0234] The chain extender can include triisocyanate. The chain extender can include tris(4-isocyanatophenyl)methane.

[0235] The chain extender can include acrylic polymer. The acrylic polymer can include acryloyl group. The acryloyl group can be bonded to the main chain as a side chain. The acrylic polymer can include epoxy group. The epoxy group can be bonded to the main chain as a side chain.

[0236] The chain extender can include styrene-based polymer. The chain extender can include styrene-based glycidyl acrylate.

[0237] The chain extender can be chemically bonded to the biodegradable polyester resin. The chain extender can be chemically bonded to the polymer included in the biodegradable polyester resin. The chain extender can be bonded to the end of the polymer included in the biodegradable polyester resin. In addition, the chain extender can be bonded to the end of three polymers included in the biodegradable polyester resin.

[0238] The chain extender can be included in the biodegradable polyester resin composition according to the embodiment at a content of about 0.1 wt% to about 10 wt%. The chain extender can be included in the biodegradable polyester resin composition according to the embodiment at a content of about 0.2 wt% to about 8 wt%. The chain extender can be included in the biodegradable polyester resin composition according to the embodiment at a content of about 0.3 wt% to about 7 wt%.

[0239] When the biodegradable polyester resin composition according to the embodiment includes the chain extender within the above range, it can have appropriate hydrolysis resistance and appropriate biodegradability.

[0240] In addition, the chain extender can react with the terminal carboxyl group or unreacted carboxyl group. Accordingly, the biodegradable polyester resin composition according to the embodiment can have a lower acid value.

[0241] Further, the chain extender couples the polymer included in the biodegradable polyester resin, and thus the biodegradable polyester resin composition according to the embodiments can increase the ratio of the high molecular weight polymer. Accordingly, the mechanical properties of the biodegradable polyester resin composition according to the embodiments can be improved.

[0242] The biodegradable polyester resin composition according to the embodiments can be effectively applied to packaging films or the like. That is, the film produced using the biodegradable polyester resin composition according to the embodiments can be used for general purposes, such as packaging. In this case, since the biodegradable polyester resin composition according to the embodiments has a relatively low initial hydrolysis degree, the biodegradable polyester film can maintain a certain level of mechanical and chemical properties during the typical use period of the user.

[0243] Further, since the biodegradable polyester resin composition according to the embodiments includes the oligomer having the above-described characteristics, it can have a relatively high late-stage hydrolysis degree. Accordingly, the film produced using the biodegradable polyester resin composition according to the embodiments can be easily decomposed when discarded after use.

[0244] Further, since the biodegradable polyester resin composition according to the embodiments includes the oligomer having the above-described characteristics, the environmental moisture decomposition and the microbial decomposition can complement each other. Accordingly, the biodegradable polyester resin composition according to the embodiments can have a relatively low initial hydrolysis degree while exhibiting a relatively high biodegradability.

[0245] Further, since the biodegradable polyester resin composition according to the embodiments includes the oligomer having the above-described characteristics, it can have a biodegradability of about 1.5 times or more per unit aliphatic carboxylic acid. That is, the biodegradable polyester resin composition according to the embodiments exhibits a relatively high biodegradability even though the aliphatic carboxylic acid content is relatively low.

[0246] Accordingly, since the biodegradable polyester resin composition according to the embodiments has a relatively high aromatic carboxylic acid content, it can exhibit a relatively high initial resistance to hydrolysis while maintaining a relatively high biodegradability in the late stage.

[0247] The biodegradable polyester resin composition according to the embodiments can maintain a certain level or more of mechanical and chemical properties during the use period of the user. At the same time, since the biodegradable polyester resin composition according to the embodiments has a relatively high late-stage hydrolysis degree, it is easily decomposed in rivers or the sea. That is, the biodegradable polyester resin composition according to the embodiments can contribute to solving environmental problems, such as the marine plastic problem.

[0248] The biodegradable polyester resin composition according to the embodiments can include a heat stabilizer. The heat stabilizer can be a phosphorus-based heat stabilizer.

[0249] The heat stabilizer can be at least one selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentamine, triethylphosphine acetate, phosphoric acid, phosphorous acid, polyphosphoric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethylphosphine, triphenylphosphine, and the like.

[0250] In addition, the heat stabilizer can be an antioxidant having an antioxidant function.

[0251] The content of the heat stabilizer can be about 3000 ppm or less based on the total weight of the biodegradable polyester resin. The content of the heat stabilizer can 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 2,000 ppm based on the total weight of the biodegradable polyester resin. When the content of the heat stabilizer satisfies this range, degradation of the polymer due to high temperature during the reaction can be controlled, thereby reducing the end group of the polymer, and improving the color. In addition, the heat stabilizer can inhibit the activation of the titanium-based catalyst, thereby controlling the reaction rate.

[0252] The biodegradable polyester resin composition according to the embodiments can include an elongation improver. Examples of the elongation improver include oils such as paraffin oil, naphthenic oil, or aromatic hydrocarbon oil, or adipates such as dibutyl adipate, diethylhexyl adipate, dioctyl adipate, or diisopropyl adipate.

[0253] The elongation improver can be included in the biodegradable polyester resin composition according to the embodiments in 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 improver can be included in the biodegradable polyester resin composition according to the embodiments in 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.

[0254] The biodegradable polyester resin composition according to the embodiments can have improved mechanical properties due to the content of the elongation improver being within the above range.

[0255] The biodegradable polyester resin composition according to the embodiments can include an inorganic filler. The inorganic filler can be at least one selected from the group consisting of calcium sulfate, barium sulfate, talc, talc powder, bentonite, kaolinite, chalk powder, calcium carbonate, graphite, gypsum, conductive carbon black, calcium chloride, iron oxide, aluminum oxide, potassium oxide, dolomite, silica, wollastonite, titanium dioxide, silicate, mica, glass fiber, mineral fiber, and the like.

[0256] In the particle size distribution of the inorganic filler obtained by laser diffraction, the volume-based cumulative 50% particle size (D50) can be about 100 pm or less, about 85 pm or less, about 70 pm or less, about 50 pm or less, about 25 pm or less, about 10 pm or less, about 5 pm or less, about 3 pm or less, or about 1 pm or less. 50 ) can be about 100 pm or less, about 85 pm or less, about 70 pm or less, about 50 pm or less, about 25 pm or less, about 10 pm or less, about 5 pm or less, about 3 pm or less, or about 1 pm or less.

[0257] Further, the specific surface area of the inorganic filler can be about 100 m 2 / g or more. For example, the specific surface area of the inorganic filler can be about 100 m 2 / g or more, about 105 m 2 / g or more, or about 110 m 2 / g or more.

[0258] The inorganic filler can be included in the biodegradable polyester resin composition according to the embodiment in a content 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 can be included in the biodegradable polyester resin composition according to the embodiment in a content of about 5 parts by weight to about 30 parts by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0259] The inorganic filler can be included in a content of about 3,000 ppm or less, based on the total weight of the biodegradable polyester resin composition according to the embodiment. For example, the content of the inorganic filler can 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 embodiment, particularly 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.

[0260] Since the biodegradable polyester resin composition according to the embodiment includes the inorganic filler within the above-described range, the biodegradable polyester resin composition according to the embodiment can have mechanical properties, appropriate UV resistance, an appropriate biodegradation rate, and an appropriate hydrolysis rate.

[0261] The biodegradable polyester resin composition according to the embodiment can further include a heterogeneous biodegradable resin. The biodegradable polyester resin composition according to the example can be a composite resin composition including two or more resins, fillers, and additives.

[0262] The heterogeneous biodegradable resin can be at least one selected from the group consisting of polybutylene azelate terephthalate (PBAzT), polybutylene sebacate terephthalate (PBSeT), polybutylene succinate terephthalate (PBST), polyhydroxyalkanoate (PHA), or polylactic acid (PLA).

[0263] The heterogeneous biodegradable resin can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 10 parts by weight to about 100 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The heterogeneous biodegradable resin can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 10 parts by weight to about 60 parts by weight, based on 100 parts by weight of the biodegradable polyester resin. The heterogeneous biodegradable resin can be contained in the biodegradable polyester resin composition according to the embodiments in a content of about 20 parts by weight to about 50 parts by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0264] The heterogeneous biodegradable resin can supplement the mechanical properties, optical properties, and chemical properties of the biodegradable polyester resin. Since the biodegradable polyester resin composition according to the embodiments contains the heterogeneous biodegradable resin in the above content, the biodegradable polyester resin composition according to the embodiments can have mechanical properties, proper UV resistance, proper biodegradation rate, and proper hydrolysis rate.

[0265] In addition, the number of carboxyl end groups of the biodegradable polyester resin composition according to the embodiments can be about 50 equivalents / ton or less. For example, the number of carboxyl end groups of the biodegradable polyester resin according to the embodiments can be about 50 equivalents / ton or less, about 48 equivalents / ton or less, about 45 equivalents / ton or less, or about 42 equivalents / ton or less. Adjusting the number of carboxyl end groups to this range can prevent deterioration and achieve improved mechanical properties when the biodegradable polyester resin composition according to the embodiments is extruded to form a molded article.

[0266] Further, the biodegradable polyester resin composition according to embodiments can have an intrinsic viscosity (IV) of about 0.9 dl / g or more. The biodegradable polyester resin composition according to embodiments can have an intrinsic viscosity of about 0.95 dl / g or more, about 1.0 dl / g or more, about 1.1 dl / g or more, about 1.2 dl / g or more, or about 1.3 dl / g or more. The biodegradable polyester resin composition according to embodiments can have an intrinsic viscosity of about 0.95 dl / g to about 1.7 dl / g. The biodegradable polyester resin composition according to embodiments can have an intrinsic viscosity of about 1.3 dl / g to about 1.7 dl / g. The biodegradable polyester resin composition according to embodiments can have an intrinsic viscosity of about 1.4 dl / g to about 1.7 dl / g.

[0267] The preparation process of the biodegradable polyester resin composition according to embodiments is as follows.

[0268] Referring to Figure 1 The apparatus for producing a biodegradable polyester resin includes a slurry agitator 100, an esterification section 200, a polycondensation reaction section 300, a post-treatment section 400, a first recovery section 510, and a second recovery section 520.

[0269] The preparation method of the biodegradable polyester resin includes a step of preparing a first raw material composition including a diol and an aromatic dicarboxylic acid.

[0270] The first raw material composition can be prepared as a slurry including a diol and an aromatic dicarboxylic acid.

[0271] The step of preparing the slurry includes a step of mixing and processing the diol and the aromatic dicarboxylic acid. That is, the step of preparing the slurry is a pretreatment step before esterification, and can be a step of mixing the diol and the aromatic dicarboxylic acid and slurring the mixture.

[0272] The slurry temperature of the diol and the aromatic dicarboxylic acid can be about 5℃ to about 45℃ higher than the melting point of the diol. For example, when the diol is 1,4-butanediol, the slurry temperature can be about 35℃ to about 70℃.

[0273] The diol and the aromatic dicarboxylic acid are supplied to the slurry agitator 100 and agitated, thereby preparing a slurry.

[0274] By mixing, pretreating, and slurring the diol and the aromatic dicarboxylic acid, the diol and the aromatic dicarboxylic acid can uniformly react, and the esterification speed can be effectively accelerated, thereby improving the reaction efficiency.

[0275] In particular, when the aromatic dicarboxylic acid such as terephthalic acid has complete crystallinity and is in a powder form, it can be difficult to induce a homogeneous reaction due to its extremely low solubility in diols. Accordingly, the slurry pretreatment process can play a very important role in providing the biodegradable polyester resin, sheet, film, and molded article having excellent properties according to embodiments of the present application and improving the reaction efficiency.

[0276] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid is a white crystal having complete crystallinity and sublimates at about 300°C under atmospheric pressure without a melting point. In addition, the solubility of terephthalic acid in diols is very low, making it difficult to occur a homogeneous reaction. Accordingly, when a pretreatment process is performed before esterification, a uniform reaction can be facilitated by increasing the surface area of terephthalic acid solids reacting with diols.

[0277] In addition, when the aromatic dicarboxylic acid is dimethyl terephthalate, it can be in a molten state at about 142°C to 170°C and react with diols through the pretreatment process, so that esterification can be performed more quickly and efficiently.

[0278] Meanwhile, in the pretreatment step of preparing a slurry, the structure and properties of the biodegradable polyester resin can vary depending on the particle size, particle size distribution, pretreatment reaction conditions, etc. of the aromatic dicarboxylic acid.

[0279] For example, the aromatic dicarboxylic acid can include terephthalic acid, and the average particle size (D50) of the terephthalic acid measured in the particle size distribution (PSD) by a particle size analyzer Microtrac S3500 can be 10 μm to 400 μm, and the standard deviation of the average particle size (D50) can be 100 or less. The standard deviation refers to the square root of the variance. The average particle size (D50) of the terephthalic acid can be, for example, 20 μm to 200 μm, for example, 30 μm to 200 μm, or for example, 100 μm to 160 μm. When the average particle size (D50) of the terephthalic acid satisfies this range, it can be more advantageous in improving the solubility and reaction rate of diols.

[0280] In the pretreatment process, diols and aromatic dicarboxylic acids can be mixed and supplied to a slurry agitator (tank) 100.

[0281] The slurry agitator 100 can be provided with, for example, an anchor type bottom, a mixer having a height of 20 mm or more, and three or more rotating blades, which are more advantageous to achieve an efficient stirring effect.

[0282] For example, the slurry stirrer 100 has a height of 20 mm or more, that is, the bottom of the reactor and the stirrer can be attached to each other. In this case, a slurry without precipitation can be obtained. If the shape, shape, and rotating blade of the stirrer do not satisfy the conditions, the aromatic dicarboxylic acid can be precipitated to the bottom at the initial stage of mixing the diol and the aromatic dicarboxylic acid. In this case, phase separation can occur.

[0283] The pre-treatment step of preparing the slurry can include the steps of mixing the diol and the aromatic dicarboxylic acid, and stirring the mixture at about 30°C to about 100°C at about 50 rpm to about 200 rpm for 10 minutes or more, for example, 10 minutes to 200 minutes.

[0284] The diol can have the properties as described above.

[0285] The diol can be added at once, or separately. For example, the diol can be added separately at the time of mixing with the aromatic dicarboxylic acid and at the time of mixing with the aliphatic dicarboxylic acid.

[0286] The aromatic dicarboxylic acid can have the properties as described above.

[0287] In the pre-treatment step of preparing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid can be about 0.8:1 to about 2:1. In the pre-treatment step of preparing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid can be about 1.1:1 to about 1.5:1. In the pre-treatment step of preparing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid can be about 1.2:1 to about 1.8:1. In the pre-treatment step of preparing the slurry, the molar ratio of the diol to the aromatic dicarboxylic acid can be about 1.25:1 to about 1.6:1.

[0288] When the amount of the diol added is greater than that of the aromatic dicarboxylic acid, the aromatic dicarboxylic acid can be more easily dispersed.

[0289] In addition, an additive can also be added to the slurry. The nanocellulose and / or the metal salt can be added to the slurry in the form of a dispersion or a solution.

[0290] In the method of preparing a biodegradable polyester resin composition, using the slurry obtained by mixing the diol and the aromatic dicarboxylic acid and pre-treating, obtaining a prepolymer by esterification, and then subjecting the prepolymer to polycondensation, it is possible to effectively achieve the desired structural properties and physical properties of the biodegradable polyester resin according to the embodiments of the present application.

[0291] The viscosity of the first raw material composition at about 35°C can be about 300 cP to about 1000 cP. The viscosity of the first raw material composition at about 35°C can be about 400 cP to about 900 cP.

[0292] Since the first raw material composition has a viscosity within the above range, the esterification reaction can be effectively performed.

[0293] The method of preparing the biodegradable polyester resin composition according to the embodiment includes a step of preparing a second raw material composition including an aliphatic dicarboxylic acid. The second raw material composition can include a diol and an aliphatic dicarboxylic acid.

[0294] In the second raw material composition, the molar ratio of the diol to the aliphatic dicarboxylic acid can be about 1.2:1 to about 1.6:1. In the second raw material composition, the molar ratio of the diol to the aliphatic dicarboxylic acid can be about 1.25:1 to about 1.5:1.

[0295] Further, the viscosity of the second raw material composition at about 35℃ can be about 300 cP to about 1000 cP. The viscosity of the second raw material composition at about 35℃ can be about 500 cP to about 1000 cP.

[0296] Since the second raw material composition has a molar ratio and a viscosity within the above range, the esterification reaction can be effectively performed.

[0297] The method of preparing the biodegradable polyester resin can include a step of esterifying the first raw material composition and the second raw material composition to prepare a prepolymer. The first raw material composition and the second raw material composition can be reacted in an ester supply line.

[0298] In the esterification reaction, the reaction time can be shortened by using the first raw material composition and the second raw material composition. For example, the slurry obtained in the pre-treatment step can shorten the reaction time of esterification and the reaction time of the condensation polymerization described below.

[0299] The esterification reaction can be performed at least once.

[0300] In the embodiment, the esterification reaction can be performed in batches after the second raw material composition is added to the first raw material composition. That is, the first raw material composition can be fed into an esterification supply line, and the second raw material composition can be fed into the esterification supply line to perform the esterification reaction.

[0301] The second raw material composition can be added to the first raw material composition in the form of a slurry.

[0302] The esterification reaction can be performed at about 250℃ or less for about 0.5 hours to about 6 hours. Specifically, the esterification reaction can be performed at about 180℃ to about 250℃, about 185℃ to about 240℃, or about 200℃ to about 240℃ under normal pressure or reduced pressure until the byproduct water is theoretically 95%. For example, the esterification reaction can be performed for 0.5 hours to 5.5 hours, 0.5 hours to 4.5 hours, or 2 hours to 5 hours, but the present application is not limited thereto.

[0303] In the esterification, the total moles of the introduced diol can be about 1.0 to about 1.8 relative to the total moles of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. In the esterification, the total moles of the introduced diol can be about 1.1 to about 1.6 relative to the total moles of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0304] Further, the temperature of the second raw material composition including the diol and the aliphatic dicarboxylic acid can be about 5℃ to about 40℃ higher than the melting point of the diol.

[0305] Further, various additives such as nanocellulose can also be added to the slurry of the diol and the aliphatic dicarboxylic acid.

[0306] In an embodiment, after the first raw material composition is introduced into the esterification part, the first esterification can be performed. Further, after the first esterification, the second raw material composition can be introduced into the esterification part, and the second esterification can be performed together with the product of the first esterification.

[0307] The first esterification can be performed at 250℃ or less for 0.25 hours to 4 hours. Specifically, the first esterification can be performed at 180℃ to 250℃, 185℃ to 240℃, or 200℃ to 240℃ under normal pressure or reduced pressure until the theoretical amount of the byproduct water reaches 95%. For example, the first esterification can be performed for 0.25 hours to 4 hours, 0.25 hours to 3.5 hours, or 1.5 hours to 3 hours, but is not limited thereto.

[0308] The second esterification can be performed at about 250℃ or less for 0.25 hours to 3.5 hours. Specifically, the second esterification can be performed at 180℃ to 250℃, 185℃ to 240℃, or 200℃ to 240℃ under normal pressure or reduced pressure until the theoretical amount of the byproduct water reaches 95%. For example, the second esterification can be performed for 0.5 hours to 3 hours, 1 hour to 2.5 hours, or 1.5 hours to 3 hours, but is not limited thereto.

[0309] In the first esterification and the second esterification, the number ratio of the first block and the second block, etc. can be controlled by adjusting the reaction temperature and the reaction time, respectively. Further, when the esterification is divided into the first esterification and the second esterification, the overall esterification can be precisely controlled. Accordingly, when the esterification is performed in steps, the reaction stability and the reaction uniformity of the esterification can be improved.

[0310] The number average molecular weight of the prepolymer can be about 500 to about 10,000 g / mol. For example, the number average molecular weight of the prepolymer can be about 500 to about 8,500 g / mol, about 500 to about 8,000 g / mol, about 500 to about 7,000 g / mol, about 500 g / mol to about 5,000 g / mol, or about 1,500 g / mol to about 4,000 g / mol. When the number average molecular weight of the prepolymer satisfies this range, the molecular weight of the polymer in the polycondensation reaction can be effectively increased.

[0311] The number average molecular weight can be measured using gel permeation chromatography (GPC). Specifically, the data obtained by gel permeation chromatography includes a plurality of indices such as Mn, Mw, and Mp. Among them, the molecular weight can be measured based on the number average molecular weight (Mn).

[0312] The reinforcing material, the branching agent, and / or the metal salt can be added together with the slurry before esterification. The reinforcing material, the branching agent, and / or the metal salt can be supplied to the esterification section 200 in the middle of esterification. The reinforcing material, the branching agent, and / or the metal salt can be added to the esterification product after esterification. Furthermore, the reinforcing material, the branching agent, and / or the metal salt can be added together with the aliphatic dicarboxylic acid. Furthermore, the reinforcing material, the branching agent, and / or the metal salt can be supplied to the esterification section 200 after the first esterification and before the second esterification.

[0313] Since the reinforcing material and / or the metal salt is added during esterification, the reinforcing material and / or the metal salt can be uniformly dispersed in the biodegradable polyester resin.

[0314] The reinforcing material can have the above-described properties. Specifically, nanocellulose can be used as the reinforcing material.

[0315] The nanocellulose can be pretreated by a bead mill, pretreated by ultrasonic waves, or pretreated by high-speed dispersion at about 1,000 rpm to about 1,500 rpm before being introduced. Specifically, the nanocellulose can be a water-dispersible nanocellulose pretreated by a bead mill or pretreated by ultrasonic waves.

[0316] First, the bead mill pretreatment can be performed using a vertical mill or a horizontal mill as a wet milling device. The horizontal mill is preferred because a larger number of beads can be loaded into the cavity, and uneven wear of the machine is reduced, wear of the beads is reduced, and maintenance is easier, but is not limited thereto.

[0317] The bead mill pretreatment can be performed using one or more bead types selected from the group consisting of zirconium, zircon, zirconia, quartz, and alumina.

[0318] 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 can 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.

[0319] When the diameter of the beads meets the range, the dispersibility of the nanocellulose can be further improved. When the diameter of the beads exceeds the range, the average particle diameter and the average particle deviation of the nanocellulose can increase, resulting in a decrease in dispersibility.

[0320] In addition, in the bead mill pretreatment, beads having a higher specific gravity than the nanocellulose are preferably used so as to be able to deliver sufficient energy. For example, the beads can be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and alumina, the specific gravity of which is higher than that of the water-dispersed nanocellulose, and zirconium beads having a specific gravity four times or more higher than that of the water-dispersed nanocellulose are preferred, but are not limited thereto.

[0321] In addition, the ultrasonic wave pretreatment is a method of physically closing or pulverizing nanoparticles using waves generated by emitting 20 kHz ultrasonic waves into a solution.

[0322] The ultrasonic wave pretreatment can be performed for less than 30 minutes at an output of 30000 J / s or less. For example, the ultrasonic wave pretreatment can be performed for 25 minutes or less, 20 minutes or less, or 18 minutes or less at an output of 25000 J / s or less or 22000 J / s or less. When the output and the execution time meet the above-described range, the effect of the ultrasonic wave pretreatment, that is, the improvement in dispersibility, can be maximized. When the energy exceeds the above-described range, the nanoparticles can rather re-agglomerate, and the dispersibility can decrease.

[0323] The nanocellulose according to the embodiments can be pretreated with a bead mill or pretreated with an ultrasonic wave. Alternatively, the nanocellulose according to the embodiments can be pretreated with a bead mill and pretreated with an ultrasonic wave. Among them, the ultrasonic wave pretreatment is preferably performed after the bead mill pretreatment to prevent re-agglomeration, thereby improving dispersibility.

[0324] The nanocellulose according to the embodiments can be pretreated with a bead mill or pretreated with an ultrasonic wave. Alternatively, the nanocellulose according to the embodiments can be pretreated with a bead mill and pretreated with an ultrasonic wave. Among them, the ultrasonic wave pretreatment is preferably performed after the bead mill pretreatment to prevent re-agglomeration, thereby improving dispersibility.

[0325] Since the nanocellulose contains ionically bonded metals, it has very high dispersibility in water. Further, by the pretreatment with a bead mill and / or the pretreatment with ultrasonic waves, an aqueous dispersion of the nanocellulose having a very high dispersibility can be obtained. In the aqueous dispersion of the nanocellulose, the content of the nanocellulose can be about 0.5 wt% to about 50 wt%. In the aqueous dispersion of the nanocellulose, the content of the nanocellulose can be about 0.5 wt% to about 20 wt%. In the aqueous dispersion of the nanocellulose, the content of the nanocellulose can be about 0.5 wt% to about 10 wt%. In the aqueous dispersion of the nanocellulose, the content of the nanocellulose can be about 0.5 wt% to about 5 wt%.

[0326] In the esterification, a titanium-based catalyst and / or a germanium-based catalyst can be used. Specifically, the titanium-based catalyst and / or the germanium-based catalyst can be added to the slurry, and then the esterification can be performed.

[0327] Further, the titanium-based catalyst and / or the germanium-based catalyst can be added to the slurry before the first esterification, and the titanium-based catalyst and / or the germanium-based catalyst can be further added to the product of the first esterification.

[0328] The biodegradable polyester resin can contain one or more titanium-based catalysts selected from the group consisting of titanium isopropoxide, antimony trioxide, dibutyl tin oxide, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, antimony acetate, calcium acetate, and magnesium acetate, or one or more germanium-based catalysts selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethyl germanium, tetraethyl germanium, and germanium sulfide.

[0329] Further, the content of the catalyst can be about 100 ppm to 1000 ppm, based on the total weight of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. For example, about 100 ppm to about 800 ppm, about 150 ppm to about 700 ppm, about 200 ppm to about 600 ppm, or about 250 ppm to about 950 ppm of the titanium-based catalyst or the germanium-based catalyst can be contained. When the content of the catalyst satisfies this range, the physical properties can be further improved.

[0330] Further, the heat stabilizer can be added to the slurry before the esterification. The heat stabilizer can be supplied to the esterification section 200 at the middle of the esterification. The heat stabilizer can be added to the esterification product after the esterification. Further, the heat stabilizer can be added with the aliphatic dicarboxylic acid. Further, the heat stabilizer can be supplied to the esterification section 200 after the first esterification and before the second esterification.

[0331] The properties of the heat stabilizer can be as described above.

[0332] The content of the heat stabilizer can be 3,000 ppm or less, based on the total weight of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. Specifically, the content of the heat stabilizer can be, for example, 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 200 ppm, based on the total weight of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. When the content of the heat stabilizer satisfies this range, the deterioration of the polymer due to high temperature during the reaction can be controlled, thereby reducing the end group of the polymer and improving the color.

[0333] After the esterification is completed, one or more selected from the group consisting of an additive (such as silica, potassium, or magnesium) and a color correction agent (such as cobalt acetate) can be further added to the esterification product. That is, after the esterification is completed, the additive and / or the color correction agent can be added and stabilized, and then the polycondensation reaction can be performed. The additive and / or the color correction agent can be added after the esterification is completed, and can be supplied to the polycondensation reaction part 300 together with the prepolymer. Accordingly, the additive and / or the color correction agent can be uniformly dispersed in the biodegradable polyester resin.

[0334] Further, after the esterification is completed, an inorganic filler can be added to the esterification product. That is, after the esterification is completed, the inorganic filler is added and stabilized, and then the polycondensation reaction can be performed. The properties of the inorganic filler are as described above. The inorganic filler can be supplied to the polycondensation reaction part 300 together with the prepolymer, and the condensation polymerization process can be performed. Accordingly, the inorganic filler can be uniformly dispersed in the biodegradable polyester resin.

[0335] Further, the first recovery part 510 recovers by-products, such as water, from the esterification part 200. The first recovery part 510 can recover the by-products generated by the esterification by applying vacuum pressure or performing reflux to the esterification part 200.

[0336] The method of preparing a biodegradable polyester resin includes a step of polycondensing the prepolymer. The polycondensation reaction can be performed as follows.

[0337] The prepolymer is supplied to the polycondensation reaction part 300. Further, at least one of the reinforcing material, the heat stabilizer, the color correction agent, the inorganic filler, the metal salt, and other additives can be supplied to the polycondensation reaction part 300 together with the prepolymer.

[0338] Further, the prepolymer can be introduced into the polycondensation reaction part, and the polycondensation reaction of the prepolymer can be performed.

[0339] The polycondensation reaction can be performed 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 performed at about 190°C to about 270°C, about 210°C to about 260°C, or about 230°C to about 255°C, at about 0.9 torr or less, about 0.7 torr or less, about 0.2 torr to about 10 torr, about 0.2 torr to about 0.9 torr, or about 0.2 torr to about 0.6 torr, for about 1.5 hours to about 5 hours, about 2 hours to about 5 hours, or about 2.5 hours to about 4.5 hours.

[0340] Further, the polycondensation reaction can include a first polycondensation and a second polycondensation.

[0341] For example, the first polycondensation can be performed at about 260°C or less, about 250°C or less, about 215°C to about 250°C, about 215°C to about 245°C, or about 230°C to about 245°C, at about 1 torr to about 200 torr, about 2 torr to about 100 torr, about 4 torr to about 50 torr, about 5 torr to about 45 torr, or about 8 torr to about 32 torr, 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.

[0342] Further, the second polycondensation can be performed at about 220°C to about 265°C, about 230°C to about 260°C, or about 235°C to about 255°C, at about 1 torr or less, about 0.8 torr or less, about 0.6 torr or less, about 0.1 torr to about 1 torr, about 0.2 torr to about 0.8 torr, or about 0.2 torr to about 0.6 torr, 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.

[0343] Further, a titanium-based catalyst or a germanium-based catalyst can be further added to the prepolymer before the polycondensation reaction. Further, one or more selected from the group consisting of an additive such as silica, potassium, or magnesium; an amine-based stabilizer such as trimethyl phosphate, triphenyl phosphate, trimethyl phosphine, phosphoric acid, phosphorous acid, or tetraethylenepentamine; and a polymerization catalyst such as antimony trioxide, antimony trioxide, or tetrabutyl titanate can be further added to the prepolymer before the polycondensation reaction.

[0344] The number average molecular weight of the polymer can be about 30000 g / mol or more. For example, the number average molecular weight of the polymer can be about 33000 g / mol or more, about 45000 g / mol or more, or about 30000 g / mol to about 120000 g / mol. When the number average molecular weight of the polymer satisfies this range, the physical properties, impact resistance, durability, and moldability thereof can be further improved.

[0345] Further, the second recovery part 520 recovers by-products, such as water, from the polycondensation reaction part 300. The second recovery part 520 can apply a vacuum pressure to the polycondensation reaction part 300, and can recover by-products generated in the polycondensation reaction.

[0346] The second recovery part 520 can apply a vacuum pressure of about 0.1 Torr to about 1 Torr to the inside of the polycondensation reaction part 300. The second recovery part 520 can apply a vacuum pressure of about 0.1 Torr to about 0.9 Torr to the inside of the polycondensation reaction part 300.

[0347] Next, the anti-hydrolysis agent and / or the chain extender are added to the polymer. Next, the polymer, the anti-hydrolysis agent, and the chain extender are uniformly mixed, and are left for about 1 minute to about 15 minutes at about 200℃ to about 260℃. Accordingly, the polymer reacts with the anti-hydrolysis agent and / or the chain extender.

[0348] Alternatively, the anti-hydrolysis agent and / or the chain extender can be supplied into the polycondensation reaction part 300 through a static mixer, and react with the polymer. The reaction temperature of the anti-hydrolysis agent and / or the chain extender in the polycondensation reaction part 300 can be about 200℃ to about 260℃. Further, the reaction time of the anti-hydrolysis agent and / or the chain extender in the polycondensation reaction part 300 can be about 1 minute to about 15 minutes.

[0349] The anti-hydrolysis agent can have the above-described properties.

[0350] The chain extender can have the above-described properties.

[0351] Accordingly, the biodegradable polyester resin composition according to the embodiment can have an appropriate degree of hydrolysis and a higher degree of biodegradation.

[0352] Next, pellets can be produced from the polymer.

[0353] Specifically, the pellets can be produced by cooling the polymer to about 15℃ or less, about 10℃ or less, or about 6℃ or less, and then cutting the cooled polymer. Alternatively, the polymer can be cut at about 40℃ to about 60℃.

[0354] The cutting step can be performed using any pellet cutter used in the art, without limitation, and the pellets can have various shapes. The pellet cutting method can include an underwater cutting method or a wire cutting method.

[0355] The pellets can undergo an additional post-treatment process. The pellets can be supplied into the post-treatment part 400, and then the post-treatment process can be performed.

[0356] The post-treatment process can be performed in the post-treatment part 400. The pellets are supplied into the post-treatment part 400. Next, the post-treatment part 400 can melt and re-extrude the supplied pellets by frictional heat. That is, the post-treatment part 400 can include an extruder such as a twin-screw extruder.

[0357] The temperature of the post-treatment process can be about 140℃ to about 250℃. The temperature of the post-treatment process can be about 130℃ to about 240℃. The temperature of the post-treatment process can be about 140℃ to about 235℃. The temperature of the post-treatment process can be about 135℃ to about 230℃.

[0358] The post-treatment process time can be about 30 seconds to about 3 minutes. The post-treatment process time can be about 50 seconds to about 2 minutes. The post-treatment process time can be about 1 minute to about 2 minutes.

[0359] Next, the resin extruded from the extruder can be cooled, cut, and processed into post-treatment pellets. That is, the resin extruded from the extruder can be re-processed into pellets through the above-described cutting step.

[0360] The crystallinity of the pellets can be improved in the post-treatment process. In addition, the content of residues contained in the pellets can be adjusted in the post-treatment process. Specifically, the content of oligomers contained in the pellets can be controlled through the post-treatment process. The amount of residual solvent contained in the pellets can be controlled through the post-treatment process. The elongation improver contained in the pellets can be controlled through the post-treatment process.

[0361] Accordingly, the post-treatment process can appropriately control the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable polyester resin.

[0362] After the pellets are produced, the biodegradable polyester resin can be compounded with a heterogeneous biodegradable resin. In addition, at least one of an inorganic filler, a heat stabilizer, a color correction agent, an elongation improver, and other additives can be compounded with the biodegradable polyester resin and the heterogeneous biodegradable resin.

[0363] The compounding process is as follows.

[0364] The biodegradable polyester resin and the heterogeneous biodegradable resin are mixed with at least one of an inorganic filler, a heat stabilizer, a color correction agent, a metal salt, or other additives, and then supplied into an extruder. The mixed biodegradable polyester resin composition is melt-mixed in the extruder at about 120℃ to about 260℃. Next, the melt-mixed biodegradable polyester resin composition is extruded, cooled, cut, and re-pelletized. Through this process, the biodegradable polyester resin composition according to the embodiment can be prepared by combining it with a heterogeneous biodegradable resin.

[0365] A biodegradable polyester film can be prepared using the biodegradable polyester resin according to the embodiments.

[0366] The biodegradable polyester film can have a thickness of about 5 μm to about 300 μm. For example, the biodegradable polyester film can have a thickness of 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.

[0367] The biodegradable polyester film according to the embodiments can have substantially the same degree of hydrolysis and biodegradability as the biodegradable polyester resin composition described above.

[0368] Meanwhile, the biodegradable polyester film can be prepared using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0369] Specifically, the method of preparing the biodegradable polyester film can include a step of preparing the biodegradable resin composition according to the examples and a step of drying and melt-extruding the biodegradable resin composition.

[0370] In the step of drying and melt-extruding the biodegradable polyester resin composition, the drying can be performed at about 60℃ to about 100℃ for about 2 hours to about 12 hours. Specifically, the drying can be performed at about 65℃ to about 95℃, about 70℃ to about 90℃, or about 75℃ to about 85℃ for about 3 hours to about 12 hours or about 4 hours to about 10 hours. When the drying conditions of the pellets satisfy the above ranges, the quality of the biodegradable polyester film or the molded article produced can be further improved. After the drying step, the moisture content of the biodegradable polyester resin composition can be not more than about 500 ppm, based on the total weight of the biodegradable polyester resin composition.

[0371] In the drying and melt-extruding step, the melt-extrusion can be performed at a temperature of about 250℃ or less. For example, the melt-extrusion can be performed at about 245℃ or less, about 220℃ or less, about 215℃ or less, about 100℃ to about 250℃, about 120℃ to about 245℃, or about 130℃ to about 215℃. The melt-extrusion can be performed by a film blowing process.

[0372] Biodegradable polyester molded article

[0373] The biodegradable polyester molded article can be manufactured using the biodegradable polyester resin.

[0374] Specifically, the molded article can be manufactured by molding the biodegradable polyester resin composition in a method known in the art such as extrusion or injection, and the molded article can be an injection-molded article, an extrusion-molded article, a film-molded product, a blow-molded article or a blow-molded product, a 3D filament, an interior material for a building, etc., but is not limited thereto.

[0375] For example, the molded article can be in the form of a film or a sheet, which can be used as an agricultural mulch film, a disposable glove, a disposable film, a disposable bag, a food packaging material, a volume trash bag, etc.; and can be in the form of a fiber, which can be used as a woven, a knit, a nonwoven, or a rope. In addition, as shown, the molded article can be in the form of a disposable container 10, which can be used as a container for packaging food such as a lunch box. In addition, the molded article can be a molded article in various forms such as a disposable straw, a tableware (spoon), a plate, or a fork. Figure 2

[0376] In particular, since the molded article can be formed of a biodegradable polyester resin capable of improving physical properties such as impact absorption energy and hardness, in particular, impact resistance and durability, it can exhibit excellent performance when it is applied to a packaging material for low-temperature storage and transport products, an interior material for a car requiring durability, a trash bag, a mulch film, and a disposable product.

[0377] The biodegradability of the biodegradable polyester resin composition according to the embodiments can be measured by the following method.

[0378] To measure the biodegradability, the biodegradable resin composition according to the embodiments is mixed with compost and an accelerated biodegradation test is performed at 60℃ and 90% humidity. After a certain time, the number average molecular weight of the first biodegradable polyester resin composition according to the embodiments is measured using gel permeation chromatography (GPC). The biodegradability is derived by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain time by the initial number average molecular weight.

[0379] The biodegradability can be expressed by Equation 4 below:

[0380] [Equation 4]

[0381]

[0382] Here, the biodegradable polyester resin composition according to the embodiments is mixed with compost and an accelerated biodegradation test is performed at a temperature of 60℃ and a humidity of 90% for a certain time. The initial number average molecular weight of the biodegradable polyester resin composition before the accelerated biodegradation test and the number average molecular weight of the biodegradable polyester resin composition after the accelerated biodegradation test for a certain time are measured by gel permeation chromatography (GPC).​

[0383] The biodegradability is obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after biodegradation for a certain time by the initial number average molecular weight.

[0384] In addition, the compost can include about 40 wt% of pig manure, about 15 wt% of chicken manure, about 37 wt% of sawdust, about 5 wt% of zeolite, and about 3 wt% of a microbial agent.

[0385] In addition, the manufacturer of the compost is Taeheung F&G, and the product name of the compost is Geosaengto (1st compost byproduct fertilizer).

[0386] In addition, in order to measure the biodegradability, the biodegradable polyester resin composition according to the embodiment is made into a sheet having a thickness of about 300 µm. Next, the made sheet is cut into a size of about 30 mm x 30 mm to produce a flake. The flake can be mixed with the compost, and an accelerated biodegradation test can be performed.

[0387] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after one week can be 40% to about 70%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after one week can be 45% to about 65%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after one week can be 47% to about 63%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after one week can be 49% to about 62%.

[0388] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after two weeks can be about 50% to about 70%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after two weeks can be about 55% to about 68%.

[0389] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after three weeks can be about 63% to about 75%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after three weeks can be about 63% to about 73%.

[0390] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after four weeks can be about 73% to about 85%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after four weeks can be 75% to 82%.

[0391] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after six weeks can be about 80% to about 90%. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after six weeks can be about 82% to about 88%.

[0392] In the biodegradable polyester resin composition according to the embodiment, the biodegradability after nine weeks can be about 85% or more. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after nine weeks can be about 87% or more. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after nine weeks can be about 88% or more. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after nine weeks can be about 89% or more. In the biodegradable polyester resin composition according to the embodiment, the biodegradability after nine weeks can be about 90% or more.

[0393] In the biodegradable polyester resin composition according to the embodiment, the biodegradability growth rate from the 1st week to the 2nd week can be about 4% / week to about 15% / week. In the biodegradable polyester resin composition according to the embodiment, the biodegradability growth rate from the 1st week to the 2nd week can be about 5% / week to about 13% / week.

[0394] The degree of hydrolysis of the biodegradable polyester resin composition according to the embodiment can be measured by the following method.

[0395] To measure the degree of hydrolysis, the biodegradable polyester resin composition according to the example is immersed in 80℃ water (100% RH) and subjected to a hydrolysis acceleration test. After a certain period of time, the number average molecular weight of the biodegradable polyester resin composition according to the embodiment is measured using gel permeation chromatography (GPC). The degree of hydrolysis is obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after hydrolysis for a certain period of time by the initial number average molecular weight.

[0396] The degree of hydrolysis can be calculated by Equation 5 below:

[0397] [Equation 5]

[0398]

[0399] Here, the biodegradable polyester resin composition according to the embodiment is immersed in 80℃ water and then subjected to a hydrolysis acceleration test for a certain period of time. The initial number average molecular weight of the biodegradable polyester resin composition before the hydrolysis acceleration test and the number average molecular weight of the biodegradable polyester resin composition after the hydrolysis acceleration test for a certain period of time are measured by gel permeation chromatography (GPC).

[0400] The degree of hydrolysis is obtained by dividing the difference between the initial number average molecular weight and the number average molecular weight after a certain period of hydrolysis by the initial number average molecular weight.

[0401] Further, in measuring the degree of hydrolysis, the biodegradable polyester resin composition according to the embodiments is made into a sheet having a thickness of about 300 μm. Next, the made sheet is cut into a size of about 30 mm x 30 mm to produce a flake. The flake can be immersed in hot water, and a hydrolysis acceleration test can be performed.

[0402] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after one week can be about 40% to about 65%. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after one week can be about 45% to about 63%.

[0403] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after two weeks can be about 80% to about 93%. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after two weeks can be about 85% to about 92%.

[0404] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after three weeks can be about 90% to about 97%. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after three weeks can be about 91% to about 96%.

[0405] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after four weeks can be about 92% to about 99%. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after four weeks can be about 93% to about 97%.

[0406] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after six weeks can be about 94% or more. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after six weeks can be about 95% or more.

[0407] In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after nine weeks can be about 95% or more. In the biodegradable polyester resin composition according to the embodiments, the degree of hydrolysis after nine weeks can be about 96% or more.

[0408] In the biodegradable polyester resin composition according to the embodiment, the rate of increase in the degree of hydrolysis from the 1st week to the 2nd week can be about 25% / week to about 50% / week. In the biodegradable polyester resin composition according to the embodiment, the rate of increase in the degree of hydrolysis from the 1st week to the 2nd week can be about 29% / week to about 50% / week. In the biodegradable polyester resin composition according to the embodiment, the rate of increase in the degree of hydrolysis from the 1st week to the 2nd week can be about 30% / week to about 45% / week.

[0409] Since the first biodegradable resin composition has a degree of hydrolysis and a rate of increase in hydrolysis within the above ranges, the biodegradable resin composition according to the embodiment has sufficient durability in the field of daily life and can be easily hydrolyzed when discarded. That is, since the biodegradable resin composition according to the embodiment has a degree of hydrolysis and a rate of increase in hydrolysis within a proper range, it can have sufficient resistance to hydrolysis for a proper period of use in applications such as disposable packaging, etc. In addition, the biodegradable resin composition according to the embodiment, when discarded, can be easily decomposed by hydrolysis, biodegradation, etc. not only in soil but also in rivers or oceans after a sufficiently long period of time.

[0410] In the biodegradable polyester resin composition according to the embodiment, the biodegradability per unit aliphatic carboxylic acid can be about 1.5 or more. In addition, the biodegradability per unit aliphatic carboxylic acid can be about 1.65 or more. The biodegradability per unit aliphatic carboxylic acid can be about 1.75 or more. The biodegradability per unit aliphatic carboxylic acid can be about 1.8 or more. The biodegradability per unit aliphatic carboxylic acid can be about 1.85 or more. The biodegradability per unit aliphatic carboxylic acid can be about 1.90 or more. The maximum biodegradability per unit aliphatic carboxylic acid can be about 4.

[0411] The biodegradability per unit aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the proportion of the aliphatic carboxylic acid to the total dicarboxylic acid. The biodegradability per unit aliphatic carboxylic acid is a value obtained by dividing the biodegradability after 9 weeks by the molar percentage of the aliphatic carboxylic acid to the total dicarboxylic acid.

[0412] The biodegradability of the aliphatic carboxylic acid can be expressed by the following Equation 6:

[0413] [Equation 6]

[0414]

[0415] The biodegradability per aliphatic carboxylic acid can fall within a desired range by appropriately adjusting factors such as the composition of the biodegradable polyester resin (e.g., the number of first blocks, the number of second blocks, the content of aliphatic dicarboxylic acid, or the content of aromatic dicarboxylic acid), the production process conditions of the biodegradable polyester resin, the reinforcing material, the metal salt, the anti-hydrolysis agent, the chain extender, the oligomer, or the heat stabilizer.

[0416] Further, the acid value of the biodegradable polyester resin composition according to the embodiment can be about 0.01 mg KOH / g to about 3 mg KOH / g. The acid value of the biodegradable polyester resin composition according to the embodiment can be about 0.1 mg KOH / g to about 2.5 mg KOH / g. The acid value of the biodegradable polyester resin composition according to the embodiment can be about 0.1 mg KOH / g to about 2.3 mg KOH / g.

[0417] Since the biodegradable polyester resin composition according to the embodiment has an acid value within the above-described range, it can have the hydrolysis characteristics and biodegradability characteristics as described above.

[0418] Further, the biodegradable polyester resin composition according to the embodiment can include a nitrogen element. The nitrogen element can be derived from the metal salt and / or the chain extender. The content of the nitrogen element can be about 0.1 ppm to about 500 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the nitrogen element can be about 1 ppm to about 400 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the nitrogen element can be about 1 ppm to about 300 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the nitrogen element can be about 1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the embodiment.

[0419] Further, the biodegradable polyester resin composition according to the embodiment can include a silicon element. The silicon element can be derived from the anti-hydrolysis agent, etc. The content of the silicon element can be about 0.1 ppm to about 100 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the silicon element can be about 0.5 ppm to about 90 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the silicon element can be about 1 ppm to about 80 ppm based on the biodegradable polyester resin composition according to the embodiment. The content of the silicon element can be about 1 ppm to about 50 ppm based on the biodegradable polyester resin composition according to the embodiment.

[0420] Further, the biodegradable polyester resin composition according to the embodiments can include a metal element. The metal element can be derived from a metal salt. The content of the metal element can be about 0.1 ppm to about 100 ppm, based on the biodegradable polyester resin composition according to the embodiments. The content of the metal element can be about 0.5 ppm to about 90 ppm, based on the biodegradable polyester resin composition according to the embodiments. The content of the metal element can be about 1 ppm to about 80 ppm, based on the biodegradable polyester resin composition according to the embodiments. The content of the metal element can be about 1 ppm to about 50 ppm, based on the biodegradable polyester resin composition according to the embodiments.

[0421] Further, the biodegradable polyester resin composition according to the embodiments can have a surface tension, a water contact angle, a methylene iodide contact angle, a surface free energy, a dispersibility, and a polarity.

[0422] The surface tension, the water contact angle, the methylene iodide contact angle, the surface free energy, the dispersibility, and the polarity can be measured on the surface of the polyester sheet.

[0423] In the biodegradable polyester resin composition according to the embodiments, the surface tension can be about 30 dynes to about 55 dynes. In the biodegradable polyester resin composition according to the embodiments, the surface tension can be about 35 dynes to about 50 dynes.

[0424] In the biodegradable polyester resin composition according to the embodiments, the water contact angle can be about 60° to about 90°. In the biodegradable polyester resin composition according to the embodiments, the water contact angle can be about 65° to about 85°. In the biodegradable polyester resin composition according to the embodiments, the water contact angle can be about 67° to about 80°.

[0425] In the biodegradable polyester resin composition according to the embodiments, the methylene iodide contact angle can be about 20° to about 40°. In the biodegradable polyester resin composition according to the embodiments, the methylene iodide contact angle can be about 20° to about 35°.

[0426] In the biodegradable polyester resin composition according to the embodiments, the surface free energy can be about 40 mN / m to about 60 mN / m. In the biodegradable polyester resin composition according to the embodiments, the surface free energy can be about 42 mN / m to about 55 mN / m.

[0427] In the biodegradable polyester resin composition according to the embodiments, the dispersibility can be about 35 mN / m to about 55 mN / m. In the biodegradable polyester resin composition according to the embodiments, the dispersibility can be about 40 mN / m to about 50 mN / m.

[0428] In the biodegradable polyester resin composition according to the embodiment, the polarity can be about 2 mN / m to about 8 mN / m. In the biodegradable polyester resin composition according to the embodiment, the polarity can be about 3 mN / m to about 7 mN / m.

[0429] Due to the composition of the biodegradable polyester resin, oligomers, reinforcing agents, chain extenders, metal salts, anti-hydrolysis agents, heat stabilizers, etc., and processes such as esterification reaction, condensation polymerization reaction, chain extension reaction, and heat treatment reaction, etc., the biodegradable polyester resin composition according to the embodiment can have the surface tension, water contact angle, methylene iodide contact angle, surface free energy, dispersibility, and polarity within the above ranges. Accordingly, the biodegradable polyester resin composition according to the embodiment can have an appropriate degree of hydrolysis and an appropriate biodegradability.

[0430] The biodegradable polyester resin composition according to the embodiment can have a tensile strength, modulus, and elongation at break.

[0431] First, in order to measure the tensile strength, modulus, and elongation at break of the biodegradable polyester resin composition according to the embodiment, a biodegradable polyester sheet is manufactured using the biodegradable polyester resin composition according to the embodiment.

[0432] The biodegradable polyester resin composition according to the embodiment can be dried at about 80℃ for about 1 hour, placed in a stainless steel mold, and then compressed at about 210℃ under a pressure of about 10 MPa for about 3 minutes to produce a biodegradable polyester sheet having a thickness of about 300 µm.

[0433] The tensile strength, elongation at break, and modulus can be measured by the following method. Test specimens are prepared by cutting the biodegradable polyester sheet according to the embodiment based on ASTM D638 Type V. Then, the specimens are tested using a universal testing machine (UTM, Model 4206-001) of Instron Co. at a tensile speed of 100 mm / min. After the test, the tensile strength (kgf / mm 2 = 9.8 MPa), elongation at break, and modulus can be measured using the software built into the device.

[0434] In the biodegradable polyester resin composition according to the embodiment, the tensile strength can be about 30 MPa to about 60 MPa. In the biodegradable polyester resin composition according to the embodiment, the tensile strength can be about 35 MPa to about 60 MPa. In the biodegradable polyester resin composition according to the embodiment, the tensile strength can be about 40 MPa to about 60 MPa. In the biodegradable polyester resin composition according to the embodiment, the tensile strength can be about 45 MPa to about 60 MPa.

[0435] In the biodegradable polyester resin composition according to the embodiment, the elongation at break can be about 800% to about 1200%. In the biodegradable polyester resin composition according to the embodiment, the elongation at break can be about 800% to about 1100%. In the biodegradable polyester resin composition according to the embodiment, the elongation at break can be about 850% to about 1050%.

[0436] In the biodegradable polyester resin composition according to the embodiment, the modulus can be about 50 MPa to about 110 MPa. In the biodegradable polyester resin composition according to the embodiment, the modulus can be about 55 MPa to about 105 MPa. In the biodegradable polyester resin composition according to the embodiment, the modulus can be about 60 MPa to about 100 MPa. In the biodegradable polyester resin composition according to the embodiment, the modulus can be about 65 MPa to about 95 MPa. In the biodegradable polyester resin composition according to the embodiment, the modulus can be about 70 MPa to about 90 MPa.

[0437] Since the biodegradable polyester resin composition according to the embodiment has the tensile strength, the elongation at break, and the modulus within the above-described ranges, it can have appropriate mechanical properties during use.

[0438] The biodegradable polyester resin composition according to the embodiment includes a polyester resin including a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid, and a fiber-reinforced material having a low haze change rate.

[0439] The fiber-reinforced material can have high dispersibility and low agglomeration properties with respect to the diol. Accordingly, the fiber-reinforced material can be uniformly dispersed in the diol without agglomeration and can be introduced into a polyester resin manufacturing process.

[0440] Accordingly, the fiber-reinforced material can be uniformly dispersed in the biodegradable polyester resin composition according to the embodiment.

[0441] The fiber-reinforced material can have high electrical conductivity. In addition, the fiber-reinforced material can have an appropriate aspect ratio. The fiber-reinforced material can include an appropriate content of a sulfate or a carboxylate. In addition, the fiber-reinforced material can have an appropriate zeta potential. In addition, the fiber-reinforced material can have an appropriate glass transition temperature. In addition, the fiber-reinforced material can have an appropriate thermal decomposition onset temperature. In addition, the fiber-reinforced material can have an appropriate maximum thermal decomposition temperature.

[0442] Accordingly, the biodegradable polyester resin composition according to the embodiment can have improved mechanical properties, improved thermal properties, improved optical properties, and improved electrical properties.

[0443] The biodegradable polyester resin composition according to the embodiments can maintain a certain level or higher of mechanical properties and chemical properties during use by a user.

[0444] Accordingly, the biodegradable film and the biodegradable molded article according to the embodiments can have improved properties as described above.

[0445] The above is described in more detail through the following examples. However, the following examples are only for illustration of the present application, and the scope of the present application is not limited thereto.

[0446] <Preparation Example>

[0447] Cellulose nanocrystals

[0448] Product name, manufacturer: DextraCel TM , Anomera

[0449] pH: 5 to 8

[0450] Conductivity: 209 µS / cm (measured by pH meter in an aqueous dispersion of about 2 wt%)

[0451] Moisture content: 4 to 6 wt%

[0452] Diameter: 5 to 10 nm

[0453] Length: 150 to 250 nm

[0454] Carboxylate content: 0.12 to 0.2 mol / kg

[0455] Zeta potential: -40 to -50 mV

[0456] Glass transition temperature: 90.6 °C

[0457] Turbidity after 1 hour: 250 NTU

[0458] Turbidity after 2 days: 233 NTU

[0459] Turbidity after 6 days: 220 NTU

[0460] Thermal decomposition onset temperature: 226 °C

[0461] Maximum thermal decomposition temperature: 347 °C

[0462] Carboxyl group intensity based on hydroxyl group: 0.7

[0463] Preparation of pretreated cellulose nanocrystals

[0464] A dry powdered cellulose nanocrystal having a particle size of about 1 μm to about 50 μm was dispersed in water at 1% by weight, and then subjected to ultrasonic treatment for 1 minute using a tip-type ultrasonic disperser at an output of 20,000 J / s, thereby producing pretreated nanocellulose.

[0465] <EMBODIMENT>

[0466] EMBODIMENT 1

[0467] Preparation of biodegradable polyester resin

[0468] First step: pretreatment to obtain a slurry

[0469] As shown in Table 1, the pretreated nanocellulose, 1,4-butanediol (1,4-BDO) and terephthalic acid (TPA) were mixed at a molar ratio of 1.25:1 (1,4-BDO:TPA) and supplied to a slurry tank in a non-catalytic state (anchor type at the bottom of the slurry tank, agitator height of 40 mm, provided with three rotating blades). Here, the D50 of the terephthalic acid (TPA) was 130 μm. In Table 1 below, the content of the nanocellulose is expressed in wt% based on the total weight of the butanediol and terephthalic acid.

[0470] Next, the mixture was pretreated by stirring at 60°C and 100 rpm for 1 hour to obtain a slurry without phase separation. Thus, the first raw material composition was prepared in the form of a slurry.

[0471] Also, 1,4-butanediol and adipic acid were mixed at a molar ratio of about 1.3:1 to prepare a second raw material composition.

[0472] Second step: obtaining a prepolymer

[0473] The first raw material composition was supplied to the reactor through a supply line and 250 ppm of tetrabutyl titanate (Dupont, Tyzor TnBT product) as a titanium-based catalyst was supplied thereto, and then a first esterification was performed at 220°C under normal pressure for about 1 hour and 30 minutes until 95% of the byproduct water was removed.

[0474] The second raw material composition was introduced into the reaction product together with the titanium-based catalyst tetrabutyl titanate (Tyzor TnBT, Dupont product) so that the content of adipic acid (AA) reached 51 mol% based on the total moles of the dicarboxylic acid component. Here, the catalyst can be added at a content of about 200 ppm based on the total weight of the diol, aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Then, a second esterification was performed at about 210°C and atmospheric pressure for about 2 hours and 45 minutes until 95% of the byproduct water was removed, thereby obtaining a second esterification product. Thus, a prepolymer having a weight average molecular weight of about 900 g / mol was prepared.

[0475] Third step: polycondensation

[0476] The prepolymer, 400 ppm of titanium-based catalyst tetrabutyl titanate (Tyzor TnBT, Dupont product), and 200 ppm of triethyl phosphate stabilizer were introduced into a polycondensation reactor and stabilized for about 10 minutes. After that, the reaction mixture was heated to 240°C and the polycondensation reaction was performed for 3.3 hours at 0.5 torr to prepare a polymer having a weight average molecular weight of 100,000 g / mol.

[0477] Next, the polymer was cooled to 5°C, cut using a pelletizer, and biodegradable polyester resin pellets were prepared.

[0478] Examples 2 to 3 and Comparative Examples 1 to 3

[0479] As shown in Tables 1 and 2 below, the contents of the first raw material composition and the second raw material composition, the esterification time, and the polycondensation reaction time were changed. Except for the contents, the rest of the processes were basically performed according to Example 1.

[0480] [Table 1]

[0481]

[0482] [Table 2]

[0483]

[0484] Manufacture of biodegradable polyester sheet

[0485] After preparing two polytetrafluoroethylene sheets, one stainless steel (SUS) mold (area: 12 cm x 12 cm) was placed on one of the polytetrafluoroethylene sheets, and about 7 g of the prepared polyester resin pellets were put into the stainless steel (SUS) mold (area: 12 cm x 12 cm). Next, the mold was covered with the other Teflon sheet, and it was placed in the center of a hot press (manufacturer: Widlab, model name: WL 1600SA) having a surface size of about 25 cm X 25 cm. The mold was maintained at a pressure of about 10 MPa at about 210°C for about 3 minutes, and then demolded, and then immediately cooled in water at 20°C for about 30 seconds. Next, a biodegradable polyester sheet having an area of about 10 cm X 10 cm and a thickness of about 300 µm was manufactured.

[0486] Evaluation Example

[0487] Evaluation Example 1: Average particle diameter (D50) and standard deviation

[0488] Average particle diameter (D50) and standard deviation of aromatic dicarboxylic acid

[0489] Regarding the particle size distribution (PSD), the average particle diameter (D50) and the standard deviation (SD) of the aromatic dicarboxylic acid (TPA or DMT) were obtained using a Microtrac S3500 particle size analyzer (Microtrac Inc.) according to the following conditions:

[0490] Use environment:

[0491] - Temperature: 10 to 35°C, humidity: 90% RH, no condensation maximum

[0492] - D50 and SD, which are the average particle size distribution of each section, were measured.

[0493] The standard deviation refers to the square root of the variance, and can be calculated using software.

[0494] <Particle diameter of nanocellulose>

[0495] The particle size and average particle deviation of the nanocellulose were measured at 25°C, a measurement angle of 175°, using the principle of dynamic light scattering (DLS) using a Zetasizer Nano ZS (manufacturer: Malvern). Here, the peak obtained by the polydispersity index (PdI) within a confidence interval of 0.5 was taken as the particle diameter.

[0496] Evaluation Example 2: Glass transition temperature

[0497] Using a differential scanning calorimeter (DSC, Q500 of TA Instruments), 4 mg of a sample was placed in an aluminum pan and heated from 0°C to 180°C at a rate of 10°C / min. The sample was then kept constant for 5 minutes to eliminate the first thermal history. Subsequently, the sample was cooled from 180°C to -50°C at a rate of 10°C / min and kept constant for 5 minutes to complete the cooling process. Thereafter, the sample was re-heated from -50°C to 180°C at a rate of 10°C / min, and the enthalpy change of the cellulose nanocrystal due to endothermic and exothermic events was measured. During the re-heating process, the glass transition temperature (Tg) was determined.

[0498] Evaluation Example 3: Thermal decomposition onset temperature and maximum thermal decomposition temperature

[0499] After drying the cellulose nanocrystal, about 16 mg of a sample was obtained. The cellulose nanocrystal sample was placed in a thermogravimetric analyzer (TGA Q500 V20, TA Instruments) and heated from about 0°C to about 600°C at a rate of about 10°C / min under a nitrogen atmosphere. At this time, after the sample weight decreased by about 4 wt%, the thermal decomposition onset temperature, i.e., the temperature at which the weight began to further decrease, was measured. In addition, the maximum thermal decomposition temperature was the temperature at which the rate of sample weight loss was the greatest with respect to temperature.

[0500] Evaluation Example 4: Turbidity change rate

[0501] Cellulose nanocrystals (CNC) were dispersed in water at a concentration of 1 wt% for 30 minutes at a speed of 1000 rpm to obtain an aqueous dispersion of CNC. The aqueous dispersion was left to stand at room temperature for about 1 hour, then re-dispersed at a speed of about 120 rpm for about 1 minute, and the turbidity after 1 hour was measured. The aqueous dispersion was then left to stand at room temperature for 2 days, re-dispersed at a speed of about 120 rpm for about 1 minute, and the turbidity after 2 days was measured. Next, the aqueous dispersion was left to stand at room temperature for 6 days, re-dispersed at a speed of about 120 rpm for about 1 minute, and the turbidity after 6 days was measured. The first turbidity change rate was calculated by dividing the difference between the turbidity after 6 days and the turbidity after 2 days by the turbidity after 2 days. The turbidity was measured using a turbidimeter (Model WA3000K, Nippon Denshoku).

[0502] Evaluation Example 5: Carboxyl intensity with respect to hydroxyl content

[0503] An infrared spectrometer (Spectrum 3, PerkinElmer) was used to measure the CNC aqueous dispersion at a concentration of 1 wt%, and an infrared absorption spectrum was obtained. From the infrared absorption spectrum, the position of a first peak (located at a wave number of 2500 -1 to 3200 cm -1 ) and a second peak (located at a wave number of 800 cm -1 to 1600 cm -1 ) was determined. The carboxyl intensity with respect to the hydroxyl content (CHI) was calculated by dividing the maximum absorbance of the second peak (PA2) by the maximum absorbance of the first peak (PA1). The carboxyl intensity with respect to the hydroxyl content can be calculated using the following equation.

[0504] [Equation 2]

[0505] CHI = PA2 / PA1

[0506] Evaluation Example 6: Molecular weight reduction rate

[0507] The biodegradable polyester resin sheets of Examples and Comparative Examples were prepared into thin pieces (about 3 cm x 3 cm) and mixed with compost (manufacturer: Taeheung F&G, product name: Jisaengto (1st grade byproduct fertilizer), compost composition: 40 wt% pig manure, 15 wt% poultry manure, 37 wt% sawdust, 5 wt% zeolite, 3 wt% microbial preparation), and biodegradation acceleration tests were performed at 60°C and 90% humidity. The number average molecular weight of the polyester resin compositions of Examples and Comparative Examples after 63 days was determined using gel permeation chromatography (GPC). The molecular weight reduction rate was calculated by dividing the difference between the initial number average molecular weight and the number average molecular weight after a specified period of time by the initial number average molecular weight.

[0508] The GPC device and measurement conditions were as follows:

[0509] Sample pretreatment: 0.035 mg of PBAT chip was dissolved in 1.5 ml of THF

[0510] Measurement device: e2695 manufactured by Waters

[0511] Flow rate: 1 ml / min in THF

[0512] Flow rate: 50 μl

[0513] Column temperature: 40°C

[0514] Detector: ELSD

[0515] Column: Styragel column HR 5E, HR4, HR2

[0516] [Equation 4]

[0517]

[0518] Evaluation Example 7: Biodegradability

[0519] For the samples manufactured in the examples and comparative examples, biodegradability was determined by measuring the amount of carbon dioxide generated according to KS M3100-1. Specifically, an inoculum container containing only compost produced at a compost plant was prepared, and a test container to which a film was added in a volume of 5% by weight based on the dry weight of the compost was prepared. Next, incubation was performed for 180 days under conditions in which the temperature was 58±2°C, the moisture content was 50%, and the oxygen concentration was 6% or more. The carbon dioxide generated in each container was captured and titrated with a phenolphthalein aqueous solution to measure the amount of carbon dioxide generated in each container. Based on the measured carbon dioxide generation amount, biodegradability was calculated according to the following Equation 7.

[0520] [Equation 7]

[0521]

[0522] Evaluation Example 8: Tensile strength, modulus, and elongation at break

[0523] The polyester sheet having a thickness of about 300 μm manufactured from the examples and comparative examples was cut into test specimens according to ASTM D638 Type V.

[0524] Tensile tests were performed using a universal testing machine (UTM, Model 4206-001, Instron) at a tensile speed of 100 mm / min. The tensile strength (kgf / mm 2 = 9.8 MPa), the elongation at break, and the modulus were measured using the software built into the device.

[0525] Modulus, tensile strength, and elongation at break of the biodegradable resin compositions of Examples and Comparative Examples were measured as shown in Table 3 below.

[0526]

Table 3

[0527]

[0528] Molecular weight reduction rate and biodegradability were obtained as shown in Table 4 below.

[0529]

Table 4

[0530] Category Molecular weight reduction rate (%) Biodegradability (%) Example 1 90 90 Example 2 91 92 Example 3 91 91.5 Comparative Example 1 90 90 Comparative Example 2 83 81

[0531] As shown in Table 3 and Table 4, the biodegradable resin compositions according to the Examples exhibit improved mechanical strength and biodegradability.

Claims

1. A biodegradable polyester resin composition comprising: a polyester resin comprising a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and fiber-reinforced materials, in, The first turbidity change rate of the fiber reinforced material measured by the following method is less than 15%: [Measurement method] 1) dispersing the fiber reinforcement material in water at a concentration of 1 wt % at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber reinforcement material; 2) allowing the aqueous dispersion to stand at room temperature for 2 days, redispersing at 120 rpm for 1 minute, and measuring a first turbidity of the aqueous dispersion; 3) allowing the aqueous dispersion to stand at room temperature for 6 days, redispersing at 120 rpm for 1 minute, and measuring a second turbidity of the aqueous dispersion; 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

2. The biodegradable polyester resin composition according to claim 1, wherein The second turbidity change rate of the fiber reinforced material measured by the following method is less than 20%: [Measurement method] 1) allowing the aqueous dispersion to stand for 1 hour, redispersing at 120 rpm for 1 minute, and then measuring the initial turbidity of the aqueous dispersion; 2) The second turbidity change rate is a value obtained by dividing the difference between the first turbidity and the initial turbidity by the first turbidity.

3. The biodegradable polyester resin composition according to claim 1, wherein The fiber reinforcement material has an elongated shape with a diameter of 1 nm to 20 nm and a length of 30 nm to 500 nm.

4. The biodegradable polyester resin composition according to claim 1, wherein The fiber reinforcement material includes sulfur in an amount of 0.5 wt % to 1.5 wt %.

5. The biodegradable polyester resin composition according to claim 4, wherein The fiber reinforcement material includes a surface treatment agent, the surface treatment agent includes sulfate or carboxylate, and the content of the surface treatment agent is 0.1 mol / kg to 0.5 mol / kg.

6. The biodegradable polyester resin composition according to claim 1, wherein The zeta potential of the fiber reinforcement material is -60 mV to -25 mV.

7. The biodegradable polyester resin composition according to claim 1, wherein The glass transition temperature of the fiber reinforcement material is 80°C to 100°C.

8. The biodegradable polyester resin composition according to claim 1, wherein The thermal decomposition starting temperature of the fiber reinforcement material is 200°C to 240°C, and The maximum thermal decomposition temperature of the fiber reinforcement material is 300°C to 360°C.

9. The biodegradable polyester resin composition according to claim 1, wherein The fiber reinforcement material contains an alkali metal.

10. The biodegradable polyester resin composition according to claim 1, wherein The fiber reinforcement material includes sulfate in an amount of 0.1 mol / kg to 0.5 mol / kg.

11. The biodegradable polyester resin composition according to claim 1, wherein The fiber reinforcement material has a carboxyl strength based on hydroxyl groups of 0.2 to 0.8 as measured by the following method: [Measurement method] 1) obtaining an infrared absorption spectrum of the aqueous dispersion of the fiber-reinforced material using infrared spectroscopy; 2) From the infrared absorption spectrum, at the wave number of 2782cm -1 to 2991cm -1 The first peak was obtained at the wave number of 1531 cm -1 to 1769cm -1 The second peak was obtained at 3) The carboxyl group intensity is a value obtained by dividing the maximum absorbance of the second peak by the maximum absorbance of the first peak.

12. A biodegradable film composition comprising: a polyester resin comprising a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and fiber-reinforced materials, in, The first turbidity change rate of the fiber reinforced material measured by the following method is less than 15%: [Measurement method] 1) dispersing the fiber reinforcement material in water at a concentration of 1 wt % at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber reinforcement material; 2) allowing the aqueous dispersion to stand at room temperature for 2 days, redispersing at 120 rpm for 1 minute, and measuring a first turbidity of the aqueous dispersion; 3) allowing the aqueous dispersion to stand at room temperature for 6 days, redispersing at 120 rpm for 1 minute, and measuring a second turbidity of the aqueous dispersion; 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

13. A biodegradable molded article comprising a biodegradable polyester resin composition, wherein the biodegradable polyester resin composition comprises: a polyester resin comprising a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid; and fiber-reinforced materials, in, The first turbidity change rate of the fiber reinforced material measured by the following method is less than 15%: [Measurement method] 1) dispersing the fiber reinforcement material in water at a concentration of 1 wt % at a speed of 1000 rpm for 30 minutes to obtain an aqueous dispersion of the fiber reinforcement material; 2) allowing the aqueous dispersion to stand at room temperature for 2 days, redispersing at 120 rpm for 1 minute, and measuring a first turbidity of the aqueous dispersion; 3) allowing the aqueous dispersion to stand at room temperature for 6 days, redispersing at 120 rpm for 1 minute, and measuring a second turbidity of the aqueous dispersion; 4) The first turbidity change rate is a value obtained by dividing the difference between the second turbidity and the first turbidity by the first turbidity.

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