Biodegradable buoy and manufacturing method thereof

Abstract

The present invention provides a biodegradable buoy and a manufacturing method thereof, the biodegradable buoy comprising a biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation of 75% to 97% after 9 weeks, and a degree of hydrolysis of 35% to 65% after 1 week, and the degree of biodegradation and the degree of hydrolysis are measured by the following measurement method 1. [Measurement method 1] (see the description of the invention)

Description

Biodegradable buoy and method for manufacturing the same

[0001] The present invention relates to a biodegradable buoy and a method for manufacturing the same.

[0002]

[0003] Buoys used in the ocean are used to aid safe navigation of vessels or to indicate the location of underwater objects such as fishing gear and anchors. Traditional buoys were made of Styrofoam, which, when damaged by typhoons or waves, breaks down into microplastics. These microplastics do not decompose, causing marine pollution. In particular, the issue of waste plastics in the ocean is becoming a growing concern in relation to the global microplastic issue. Approximately 27% of waste plastics generated in Korea's oceans are from Styrofoam buoys.

[0004] To address these issues, Korean Patent No. 2261842 used PE as the buoy material, while EPP, EPE, PET, and aircell were also considered. While these materials are effective in reducing microplastics compared to Styrofoam, they are still difficult-to-decompose plastics, limiting their fundamental role as a solution as they contribute to marine pollution. Therefore, there is a need to develop a buoy that can be used in the ocean for a certain period of time and is biodegradable after use.

[0005]

[0006] The present invention provides a biodegradable buoy having excellent biodegradability and water resistance and a method for manufacturing the same.

[0007]

[0008] A biodegradable buoy according to the present invention comprises a biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation of 75% to 97% after 9 weeks, and the biodegradable resin composition has a degree of hydrolysis of 35% to 65% after 1 week, and the degree of biodegradation and the degree of hydrolysis are measured by the following measurement method 1.

[0009] [Measurement Method 1]

[0010] The biodegradability after 9 weeks is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm Х 30 mm and placed under compost conditions at a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

[0011] In one embodiment of the present invention, the wet hardness reduction rate of the biodegradable resin composition may be 15% or less, and the wet hardness reduction rate is measured by the following measurement method 2.

[0012] [Measurement Method 2]

[0013] The above biodegradable resin composition is processed into a biodegradable resin block having a thickness of 2.5 mm and a size of 10 mm X 10 mm, and the initial hardness of the biodegradable resin block and the wet hardness after the biodegradable resin block is immersed in water at 30° C. for 24 hours are measured, and the wet hardness reduction rate is a value obtained by dividing the difference in the wet hardness from the initial hardness by the initial hardness.

[0014] In one embodiment of the present invention, the biodegradable buoy may have a fracture height of more than 200 cm as measured by the following measurement method 3.

[0015] [Measurement Method 3]

[0016] A 10 kg branch-shaped weight is prepared, and the branch-shaped weight is free-falling from a height of 150 cm to strike the biodegradable buoy, and the branch-shaped weight increases the free-fall height by 10 cm from the height of 150 cm to strike the biodegradable buoy, and the breaking height is the height at which the biodegradable buoy breaks, and the branch-shaped weight is a hemisphere having a lower radius of 63 mm and includes a body portion extending upwards by a length three times the lower radius, and the diameter of the body portion extending upwards gradually decreases, and the diameter at the upper end is 63 mm.

[0017] In one embodiment of the present invention, the biodegradable buoy may have a first buoyancy maintenance rate of greater than 80% as measured by the following measurement method 4.

[0018] [Measurement Method 4]

[0019] The above biodegradable buoy is immersed in seawater at a depth of 5 m at 25°C for 23 hours, and then dried for 1 hour, a process repeated for 60 days, and the first buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 60 days to the initial buoyancy of the biodegradable buoy.

[0020] In one embodiment of the present invention, the biodegradable buoy may have a second buoyancy maintenance rate of greater than 80% as measured by the following measurement method 5.

[0021] [Measurement Method 5]

[0022] The above biodegradable buoy is immersed in warm water at 60°C for 10 hours and then immersed in water at 25°C for 10 hours, and this process is repeated 15 times, and the second buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 15 immersions to the initial buoyancy of the biodegradable buoy.

[0023] In one embodiment of the present invention, the biodegradable buoy may have a third buoyancy retention rate of greater than 90% as measured by the following measurement method 6.

[0024] [Measurement Method 6]

[0025] The biodegradable buoy is placed in a high-pressure chamber at 3 atm for 30 minutes, and the third buoyancy retention rate is the ratio of the buoyancy of the biodegradable buoy after being exposed to 3 atm for 30 minutes to the initial buoyancy of the biodegradable buoy.

[0026] In one embodiment of the present invention, the biodegradable buoy may have a fourth buoyancy retention rate of greater than 80% as measured by the following measurement method 7.

[0027] [Measurement Method 7]

[0028] The biodegradable buoy is placed between two load-applying plates facing each other, and after a load of 3,000 N is applied, the process of removing the load is repeated 20 times, and the fourth buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after the load application process is repeated 20 times to the initial buoyancy of the biodegradable buoy.

[0029] In one embodiment of the present invention, the biodegradable buoy comprises a first ring and a second ring opposite to the first ring, and when the first ring and the second ring are pulled in opposite directions, the breaking strength may exceed 5,000 N.

[0030] In one embodiment of the present invention, the biodegradable resin composition is processed into a biodegradable sheet having a thickness of 300 ㎛ and a size of 10 cm Х 10 cm, and when the biodegradable sheet is irradiated with ultraviolet rays from a UVA 340 ultraviolet lamp at an intensity of 0.75 W / ㎡, the tensile strength of the biodegradable sheet may have a reduction rate of 5% to 40% from the beginning of the ultraviolet irradiation to 1 day.

[0031] In one embodiment of the present invention, the biodegradable resin composition may include a polylactic acid-based resin and a polybutylene adipate terephthalate-based resin.

[0032] In one embodiment of the present invention, the biodegradable resin composition may include an inorganic filler and an additive.

[0033] In one embodiment of the present invention, the biodegradable resin composition may have a seawater decomposition rate of 5% to 20% after 3 months, and the seawater decomposition rate is measured at a temperature of 30°C according to ASTM D6691.

[0034] A method for manufacturing a biodegradable buoy according to the present invention comprises the steps of (a) preparing a biodegradable resin composition, and (b) injecting the biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation of 75% to 97% after 9 weeks, and the degree of hydrolysis of the biodegradable resin composition has a degree of hydrolysis of 35% to 65% after 1 week, and the degree of biodegradation and the degree of hydrolysis are measured by the following measurement method 1.

[0035] [Measurement Method 1]

[0036] The biodegradability after 9 weeks is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm Х 30 mm and placed under compost conditions at a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

[0037]

[0038] The biodegradable buoy and the method for manufacturing the same according to the present invention include a biodegradable resin composition having excellent biodegradability and water resistance, so that not only can it be used for a period of time normally required as a marine buoy, but it can also be biodegraded not only in the ocean but also on the beach after use, thereby fundamentally solving marine pollution caused by conventional buoys.

[0039] In addition, the biodegradable buoy and the method for manufacturing the same according to the present invention can maintain a specific appearance during the period of use as a marine buoy by satisfying a certain range of wet hardness reduction rates.

[0040] In addition, the biodegradable buoy and the method for manufacturing the same according to the present invention can supplement the weak weather resistance and mechanical properties of general biodegradable buoys by satisfying a certain level of fracture characteristics or higher.

[0041] In addition, the biodegradable buoy according to the present invention and the method for manufacturing the same can function properly not only under changes in temperature, pressure, etc., but also under various practical conditions in which it is used in conjunction with a rope, by satisfying a buoyancy maintenance rate of a certain level or higher.

[0042]

[0043] FIG. 1 is a drawing showing an elevation view of a branch-shaped weight for measuring the breaking height of a biodegradable buoy according to an embodiment.

[0044] Figure 2 is a schematic diagram illustrating a method for measuring the fourth buoyancy maintenance rate of a biodegradable buoy according to an embodiment.

[0045] Figure 3 is a schematic diagram illustrating a method for measuring the breaking strength of a biodegradable buoy according to an embodiment.

[0046] FIG. 4 is a schematic drawing of an apparatus for manufacturing a biodegradable resin composition according to an embodiment.

[0047] FIG. 5 is a schematic diagram illustrating a process for manufacturing a biodegradable buoy from a biodegradable resin composition according to an embodiment.

[0048]

[0049] The structural or functional descriptions of the embodiments disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the technical idea of ​​the present invention, and the embodiments according to the technical idea of ​​the present invention can be implemented in various forms other than the embodiments disclosed in this specification or application, and the technical idea of ​​the present invention is not construed as being limited to the embodiments described in this specification or application.

[0050] Additionally, when a component is referred to as "including" in this specification or application, this does not exclude other components, but rather implies the inclusion of other components, unless otherwise specifically stated. Furthermore, all numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification or application should be understood to be modified by the term "about" in all cases, unless otherwise specified. Furthermore, "ppm" in this specification or application refers to weight basis.

[0051]

[0052] Hereinafter, a biodegradable buoy according to the present invention and a method for manufacturing the same will be described.

[0053]

[0054] Biodegradable Buoy

[0055] A biodegradable buoy according to the present invention comprises a biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation of 75% to 97% after 9 weeks, and the biodegradable resin composition has a degree of hydrolysis of 35% to 65% after 1 week, and the degree of biodegradation and the degree of hydrolysis are measured by the following measurement method 1.

[0056] [Measurement Method 1]

[0057] The biodegradability after 9 weeks is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm Х 30 mm and placed under compost conditions at a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

[0058]

[0059] The above biodegradable buoy comprises a biodegradable resin composition.

[0060] The above biodegradable resin composition may include a first biodegradable resin.

[0061] The first biodegradable resin may include a diol, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. The first biodegradable resin may include a diol residue, an aromatic dicarboxylic acid residue, and an aliphatic dicarboxylic acid residue. The diol residue may be derived from the diol, the aromatic dicarboxylic acid residue may be derived from the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid residue may be derived from the aliphatic dicarboxylic acid. The first biodegradable resin may include a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component. The diol component may be derived from the diol, the aromatic dicarboxylic acid component may be derived from the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid component may be derived from the aliphatic dicarboxylic acid.

[0062] In this specification or application, the diol residue may be expressed as a diol. In this specification or application, the dicarboxylic acid residue may be expressed as a dicarboxylic acid. In this specification or application, the residue may be expressed as a component.

[0063] The above diol may be an aliphatic diol. The above diol may be a bio-derived diol. The above diols are ethanediol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2-methyl-1,8-octanediol, At least one may be selected from the group consisting of 1,9-nonanediol, 1,10-decanediol and 1,12-octadecanediol or derivatives thereof.

[0064] The above diol may be selected from the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, diethylene glycol, neopentyl glycol or derivatives thereof.

[0065] The above diol may be selected from the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol or derivatives thereof.

[0066] The above diol may include 1,4-butanediol or a derivative thereof.

[0067] The above aromatic dicarboxylic acid may be at least one selected from the group consisting of phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid or derivatives thereof.

[0068] The above aromatic dicarboxylic acid may be selected from the group consisting of terephthalic acid, dimethyl terephthalate, 2,6-naphthalene dicarboxylic acid, isophthalic acid or derivatives thereof.

[0069] The above aromatic dicarboxylic acid may include terephthalic acid, dimethyl terephthalate or derivatives thereof.

[0070] The above aliphatic dicarboxylic acid may be selected from the group consisting of oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, terbric acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or derivatives thereof.

[0071] The above aliphatic dicarboxylic acid may be selected from the group consisting of adipic acid, succinic acid, sebacic acid or derivatives thereof.

[0072] The above aliphatic dicarboxylic acid may include adipic acid or a derivative thereof.

[0073] In the first biodegradable resin, the molar ratio of the total diol residues including the diol: the total dicarboxylic acid residues including the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid may be from about 1:0.9 to about 1:1.1. The molar ratio of the total diol residues: the total dicarboxylic acid residues may be from about 1:0.95 to about 1:1.05.

[0074] In the first biodegradable resin, the molar ratio of the aromatic dicarboxylic acid residue: the aliphatic dicarboxylic acid residue may be from about 3:7 to about 7:3. In the first biodegradable resin, the molar ratio of the aromatic dicarboxylic acid residue: the aliphatic dicarboxylic acid residue may be from about 3.3:6.7 to about 6.7:3.3. In the first biodegradable resin, the molar ratio of the aromatic dicarboxylic acid residue: the aliphatic dicarboxylic acid residue may be from about 4:6 to about 6:4. In the first biodegradable resin, the molar ratio of the aromatic dicarboxylic acid residue: the aliphatic dicarboxylic acid residue may be from about 4.2:5.8 to about 5:5.

[0075] The first biodegradable resin may comprise a diol residue derived from 1,4-butanediol in an amount of about 90 mol% or more based on the total diol. The first biodegradable resin may comprise a diol residue derived from 1,4-butanediol in an amount of about 95 mol% or more based on the total diol. The first biodegradable resin may comprise a diol residue derived from 1,4-butanediol in an amount of about 98 mol% or more based on the total diol.

[0076] The first biodegradable resin may comprise an aromatic dicarboxylic acid residue derived from terephthalic acid or dimethyl terephthalate in an amount of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise an aromatic dicarboxylic acid residue derived from terephthalic acid or dimethyl terephthalate in an amount of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise a dicarboxylic acid residue derived from terephthalic acid or dimethyl terephthalate in an amount of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise an aromatic dicarboxylic acid residue derived from terephthalic acid or dimethyl terephthalate in an amount of about 43 mol% to about 53 mol% based on the total dicarboxylic acid.

[0077] The first biodegradable resin may comprise an aliphatic dicarboxylic acid residue derived from adipic acid in an amount of about 30 mol% to about 70 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise an aliphatic dicarboxylic acid residue derived from adipic acid in an amount of about 35 mol% to about 65 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise an aliphatic dicarboxylic acid residue derived from adipic acid in an amount of about 40 mol% to about 60 mol% based on the total dicarboxylic acid. The first biodegradable resin may comprise an aliphatic dicarboxylic acid residue derived from adipic acid in an amount of about 47 mol% to about 57 mol% based on the total dicarboxylic acid.

[0078] The first biodegradable resin may include a first block and a second block. The first biodegradable resin may have a molecular structure in which the first block and the second block are alternately bonded.

[0079] The first block may include the diol residue and the aromatic dicarboxylic acid residue. The first block may be formed by an esterification reaction of the diol and the aromatic dicarboxylic acid. The first block may include only the diol residue and the aromatic dicarboxylic acid residue. The first block may include only repeating units formed by an esterification reaction of the diol and the aromatic dicarboxylic acid. That is, the first block may mean the sum of repeating units of the diol and the aromatic dicarboxylic acid before the aliphatic dicarboxylic acid is bonded.

[0080] The second block may include the diol residue and the aliphatic dicarboxylic acid residue. The second block may be formed by an esterification reaction of the diol and the aliphatic dicarboxylic acid. The second block may include only the diol residue and the aliphatic dicarboxylic acid residue. The second block may include only repeating units formed by an esterification reaction of the diol and the aliphatic dicarboxylic acid. That is, the second block may mean the sum of repeating units of the diol and the aliphatic dicarboxylic acid before the aromatic dicarboxylic acid is bonded.

[0081] In the first biodegradable resin, the ratio (X / Y) of the number (X) of the first block and the number (Y) of the second block may be from about 0.5 to about 1.5. In the first biodegradable resin, the ratio (X / Y) of the number (X) of the first block and the number (Y) of the second block may be from about 0.6 to about 1.4. In the first biodegradable resin, the ratio (X / Y) of the number (X) of the first block and the number (Y) of the second block may be from about 0.7 to about 1.3. In the first biodegradable resin, the ratio (X / Y) of the number (X) of the first block and the number (Y) of the second block may be from about 0.75 to about 1.2. Additionally, in the first biodegradable resin, the ratio (X / Y) of the number (X) of the first blocks and the number (Y) of the second blocks may be 0.8 to 1. The number of the first blocks may be smaller than the number of the second blocks.

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

[0083] The number of the first blocks may vary depending on the content of the aromatic dicarboxylic acid, the molecular weight of the first biodegradable resin, and the alternation ratio described below. That is, as the molar ratio of the aromatic dicarboxylic acid increases, as the molecular weight of the first biodegradable resin increases, and as the alternation ratio described below increases, the number of the first blocks may increase.

[0084] The number of the second blocks may be about 30 to about 300. The number of the second blocks may be about 40 to about 250. The number of the second blocks may be about 50 to about 220. The number of the second blocks may be about 60 to about 200. The number of the second blocks may be about 70 to about 200. The number of the second blocks may be about 75 to about 200.

[0085] The number of the second blocks may vary depending on the content of the aliphatic dicarboxylic acid, the molecular weight of the first biodegradable resin, and the degree of alternation described below.

[0086] When the first biodegradable resin comprises the first block and the second block within the above range, the biodegradable buoy according to the present invention can have appropriate mechanical strength and appropriate biodegradability. In addition, when the first biodegradable resin comprises the first block and the second block within the above range, the biodegradable buoy can have improved flexibility and, at the same time, improved rigidity.

[0087] When the first biodegradable resin includes the first block and the second block within the above range, the biodegradable buoy according to the present invention can have appropriate durability against ultraviolet rays, etc., and at the same time have appropriate biodegradability.

[0088] The above first block can be represented by the following chemical formula 1.

[0089] [Chemical Formula 1]

[0090]

[0091] In the above chemical formula 1, R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and m may be 1 to 20.

[0092] The above R1 may be a substituted or unsubstituted phenylene group, and the above R2 may be a butylene group.

[0093] The above second block can be represented by the following chemical formula 2.

[0094] [Chemical Formula 2]

[0095]

[0096] In the above chemical formula 2, R3 and R4 are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n may be 1 to 20.

[0097] The above R3 and the above R4 may be a butylene group.

[0098] The first biodegradable resin may have a structure in which the first block and the second block are alternately bonded to each other. The first biodegradable resin may be represented by the following chemical formula 3.

[0099] [Chemical Formula 3]

[0100]

[0101] In the above chemical formula 3, R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and m may be 1 to 20. In addition, R3 and R4 are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and n may be 1 to 20.

[0102] The above diol residue may include a residue of 1,4-butanediol or a derivative thereof, the above aromatic dicarboxylic acid residue may include a residue of terephthalic acid or a derivative thereof, and the above aliphatic dicarboxylic acid residue may include a residue of adipic acid or a derivative thereof.

[0103] For example, the first biodegradable resin may comprise a first block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof.

[0104] Alternatively, the first biodegradable resin may comprise a first block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of dimethyl terephthalate or a derivative thereof.

[0105] The first biodegradable resin may comprise a second block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

[0106] Alternatively, the first biodegradable resin may comprise a second block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of succinic acid or a derivative thereof.

[0107] A first biodegradable resin according to an embodiment of the present invention may include a first block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of terephthalic acid or a derivative thereof; and a second block comprising a residue of 1,4-butanediol or a derivative thereof and a residue of adipic acid or a derivative thereof.

[0108] The first block may be represented by the following chemical formula 4, and the second block may be represented by the following chemical formula 5.

[0109] [Chemical Formula 4]

[0110]

[0111] In the above chemical formula 4, m may be 1 to 20.

[0112] [Chemical Formula 5]

[0113]

[0114] In the above chemical formula 5, n may be 1 to 20.

[0115] The above first biodegradable resin can be represented by the following chemical formula 6.

[0116] [Chemical Formula 6]

[0117]

[0118] In the above chemical formula 6, m may be 1 to 20, and n may be 1 to 20.

[0119] When the first block and the second block satisfy the above configuration, it may be more advantageous to provide a biodegradable buoy with improved physical properties while having excellent biodegradability and water decomposition properties.

[0120] In addition, when the first biodegradable resin includes the first block and the second block in the above range, the biodegradable buoy according to the present invention can have appropriate mechanical properties and appropriate UV resistance properties.

[0121] Since the first block and the second block have the above-described characteristics, the mechanical properties of the biodegradable buoy according to the present invention can be improved.

[0122] Since the first block and the second block have the above-described characteristics, the biodegradable buoy according to the present invention can have appropriate UV resistance properties.

[0123] Since the first block and the second block have the above-described characteristics, the biodegradable buoy according to the present invention can have an appropriate biodegradation rate.

[0124] Since the first block and the second block have the above-described characteristics, the biodegradable buoy according to the present invention can have an appropriate hydrolysis rate.

[0125] Since the first block and the second block have the above-described characteristics, the biodegradable buoy according to the present invention can have an appropriate biodegradation rate and improved UV resistance properties.

[0126] The above first biodegradable resin may include the following bonding structures 1 to 3.

[0127] [Combination Structure 1]

[0128] Aromatic dicarboxylic acid - Diol - Aliphatic dicarboxylic acid -

[0129] [Combination Structure 2]

[0130] Aromatic dicarboxylic acid - Diol - Aromatic dicarboxylic acid -

[0131] [Combination Structure 3]

[0132] Aliphatic dicarboxylic acid - Diol - Aliphatic dicarboxylic acid -

[0133] The diol included in the above bonding structure 1 is bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid, and to the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid. The diol included in the above bonding structure 1 can be directly esterified between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid, and to the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0134] In addition, the diol included in the above bonding structure 2 is bonded between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid, and to the aromatic dicarboxylic acid and the aromatic dicarboxylic acid. The diol included in the above bonding structure 2 can be directly esterified between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid, and to the aromatic dicarboxylic acid and the aromatic dicarboxylic acid.

[0135] In addition, the diol included in the above bonding structure 3 is bonded between the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid, and to the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid. The diol included in the above bonding structure 3 can be directly esterified between the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid.

[0136] In the above first biodegradable resin, the bonding structure 1 can be represented by the following chemical formula 7.

[0137] [Chemical Formula 7]

[0138]

[0139] In the above chemical formula 7, R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and R3 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0140] In the above first biodegradable resin, the bonding structure 2 can be represented by the following chemical formula 8.

[0141] [Chemical Formula 8]

[0142]

[0143] In the above chemical formula 8, R1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, and R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0144] In the above first biodegradable resin, the bonding structure 3 can be represented by the following chemical formula 9.

[0145] [Chemical Formula 9]

[0146]

[0147] In the above chemical formula 9, R2 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and R3 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

[0148] In addition, the above bond structure 1 can be represented by the following chemical formula 10.

[0149] [Chemical Formula 10]

[0150]

[0151] In addition, the above bond structure 2 can be represented by the following chemical formula 11.

[0152] [Chemical Formula 11]

[0153]

[0154] In addition, the above bond structure 3 can be represented by the following chemical formula 12.

[0155] [Chemical Formula 12]

[0156]

[0157] The above first biodegradable resin may have an alternating ratio.

[0158] The above-mentioned alternation ratio is the ratio of the diol bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid among the diols. That is, the above-mentioned alternation ratio may be the ratio of the diol included in the bonding structure 1 among the diols. The above-mentioned alternation ratio may be a value obtained by dividing the number of moles of the diol included in the bonding structure 1 by the sum of the number of moles of the diol included in the bonding structure 1, the number of moles of the diol included in the bonding structure 2, and the number of moles of the diol included in the bonding structure 3.

[0159] That is, the above-mentioned exchange ratio may be the ratio of diols bonded between heterodicarboxylic acids among the total diols.

[0160] The above exchange ratio can be calculated using the following equation 1.

[0161] [Formula 1]

[0162]

[0163] In the above formula 1, DM1 is the molar ratio of the diol included in the bonding structure 1, DM2 is the molar ratio of the diol included in the bonding structure 2, and DM3 is the molar ratio of the diol included in the bonding structure 3.

[0164] In the first biodegradable resin, the alternation ratio may be from about 0.3 to about 0.7. In the first biodegradable resin, the alternation ratio may be from about 0.37 to about 0.59. In the first biodegradable resin, the alternation ratio may be from about 0.4 to about 0.56. In the first biodegradable resin, the alternation ratio may be from about 0.45 to about 0.53.

[0165] Additionally, the first biodegradable resin may include a hard segment ratio.

[0166] The above hard segment ratio is the ratio of the diol bonded between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid among the diols.

[0167] The above hard segment ratio may be the molar ratio of the diol included in the bonding structure 2 among the total diols. The above hard segment ratio may be a value obtained by dividing the number of moles of the diol included in the bonding structure 2 by the sum of the number of moles of the diol included in the bonding structure 1, the number of moles of the diol included in the bonding structure 2, and the number of moles of the diol included in the bonding structure 3.

[0168] The above hard segment ratio can be expressed by the following equation 2.

[0169] [Formula 2]

[0170]

[0171] In the above formula 2, DM1 is the molar ratio of the diol included in the bonding structure 1, DM2 is the molar ratio of the diol included in the bonding structure 2, and DM3 is the molar ratio of the diol included in the bonding structure 3.

[0172] The hard segment ratio may be about 0.15 to about 0.35. The hard segment ratio may be about 0.2 to about 0.3. The hard segment ratio may be about 0.21 to about 0.29. The hard segment ratio may be about 0.22 to about 0.28.

[0173] Additionally, the biodegradable resin composition may include a soft segment.

[0174] The above soft segment ratio is the ratio of the diol bonded between the aliphatic dicarboxylic acid and the aliphatic dicarboxylic acid among the diols.

[0175] The above soft segment ratio may be the molar ratio of the diol included in the bonding structure 3 among the total diols. The above soft segment ratio may be a value obtained by dividing the number of moles of the diol included in the bonding structure 3 by the sum of the number of moles of the diol included in the bonding structure 1, the number of moles of the diol included in the bonding structure 2, and the number of moles of the diol included in the bonding structure 3.

[0176] The above soft segment ratio can be expressed by the following equation 3.

[0177] [Formula 3]

[0178]

[0179] In the above formula 3, DM1 is the molar ratio of the diol included in the bonding structure 1, DM2 is the molar ratio of the diol included in the bonding structure 2, and DM3 is the molar ratio of the diol included in the bonding structure 3.

[0180] The soft segment ratio may be from about 0.16 to about 0.36. The soft segment ratio may be from about 0.21 to about 0.31. The soft segment ratio may be from about 0.22 to about 0.30. The hard segment ratio may be from about 0.23 to about 0.29.

[0181] The above soft segment ratio may be greater than the above hard segment ratio.

[0182] The ratio of the hard segment to the soft segment may be about 0.92 to about 0.99. That is, the value obtained by dividing the DM2 by the DM3 may be about 0.92 to about 0.99.

[0183] The above-mentioned alternation ratio, the hard segment ratio, and the soft segment ratio can be measured by nuclear magnetic resonance spectroscopy. The first biodegradable resin can be dissolved in a solvent such as CDCl3 and analyzed at room temperature by a nuclear magnetic resonance (NMR) device, such as 1H-NMR and / or 13C-NMR analysis.

[0184] When the diol is 1,4-butanediol, the aromatic dicarboxylic acid is terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid is adipic acid, the analysis of the first biodegradable resin by nuclear magnetic resonance spectroscopy may include a first peak, a second peak, a third peak, a fourth peak, a fifth peak, a sixth peak, a seventh peak, an eighth peak, a ninth peak, a tenth peak, and an eleventh peak.

[0185] For example, when the diol is 1,4-butanediol, the aromatic dicarboxylic acid is terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid is adipic acid, analysis of the first biodegradable resin by nuclear magnetic resonance spectroscopy may include a peak derived from the diol of the bonding structure 1, a peak derived from the diol of the bonding structure 2, and a peak derived from the bonding structure 3 at about 3.5 ppm to about 4.6 ppm.

[0186] In the range of about 3.5 ppm to about 4.6 ppm, the first peak, the second peak, the third peak, and the fourth peak may be defined in order from high ppm to low ppm. In addition, based on the ppm of the ninth peak, the first peak, the second peak, the third peak, and the fourth peak may be defined in order from high ppm to low ppm in the range of about -3.4 ppm to about -4.3 ppm. In this case, the first peak may be derived from a diol included in the second binding unit, the second peak and the third peak may be derived from a diol included in the first binding unit, and the fourth peak may be derived from a diol included in the third binding unit.

[0187] -ppm direction can be upfield or shielded. For example, -3.4 ppm can mean 3.4 ppm upfield. For example, -3.4 ppm can mean 3.4 ppm shielded.

[0188] Additionally, the analysis of the first biodegradable resin by the nuclear magnetic resonance spectroscopy may include a peak derived from the diol of the bonding structure 1, a peak derived from the diol of the bonding structure 2, and a peak derived from the bonding structure 3 at about 1.0 ppm to about 2.5 ppm.

[0189] In the range of about 1.0 ppm to about 2.5 ppm, the tenth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, and the eleventh peak may be defined in order from high ppm to low ppm. In the range of about -6.0 ppm to about -6.7 ppm based on the ppm of the ninth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, and the eleventh peak may be defined in order from high ppm to low ppm. In this case, the fifth peak may be derived from a diol included in the second binding unit, the sixth peak and the seventh peak may be derived from a diol included in the first binding unit, and the eighth peak may be derived from a diol included in the third binding unit.

[0190] Additionally, in the range of about 7.5 ppm to about 8.5 ppm, the ninth peak may be formed. The ninth peak may be derived from the aromatic dicarboxylic acid. The ninth peak may be derived from an aromatic ring included in the aromatic dicarboxylic acid. The ninth peak may be derived from an aromatic ring included in the terephthalic acid or dimethyl terephthalate.

[0191] The above tenth peak and the above eleventh peak may be derived from the aliphatic dicarboxylic acid. The above tenth peak and the above eleventh peak may be derived from the adipic acid.

[0192] The first peak may be located at about -3.6 ppm to about -3.68 ppm based on the ppm of the ninth peak. The second peak may be located at about -3.69 ppm to about -3.75 ppm based on the ppm of the ninth peak. The third peak may be located at about -3.9 ppm to about -3.97 ppm based on the ppm of the ninth peak. The fourth peak may be located at about -3.98 ppm to about -4.1 ppm based on the ppm of the ninth peak. The fifth peak may be located at about -6.0 ppm to about -6.19 ppm based on the ppm of the ninth peak. The sixth peak may be located at about -6.2 ppm to about -6.26 ppm based on the ppm of the ninth peak. The seventh peak may be located at about -6.27 ppm to about -6.34 ppm based on the ppm of the ninth peak. The eighth peak may be located at about -6.35 ppm to about -6.42 ppm based on the ppm of the ninth peak. The tenth peak may be located at about -5.6 ppm to about -5.8 ppm based on the ppm of the ninth peak. The eleventh peak may be located at about -6.421 ppm to about -6.5 ppm based on the ppm of the ninth peak. The positions based on the ppm of the ninth peak may be the positions of each peak when the position of the ninth peak is 0 ppm.

[0193] Additionally, the areas of the first peak, the second peak, the third peak, the fourth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, the tenth peak, and the eleventh peak can be normalized based on the area of ​​the ninth peak. That is, when the area of ​​the ninth peak is 1, the areas of the first peak, the second peak, the third peak, the fourth peak, the fifth peak, the sixth peak, the seventh peak, the eighth peak, the tenth peak, and the eleventh peak can be relatively determined.

[0194] The above exchange ratio can be derived from Equation 4 or Equation 5 below.

[0195] [Formula 4]

[0196]

[0197] In the above equation 4, PA1 is the area of ​​the first peak, PA2 is the area of ​​the second peak, PA3 is the area of ​​the third peak, and PA4 is the area of ​​the fourth peak.

[0198] [Formula 5]

[0199]

[0200] In the above equation 5, PA5 is the area of ​​the fifth peak, PA6 is the area of ​​the sixth peak, PA7 is the area of ​​the seventh peak, and PA8 is the area of ​​the eighth peak.

[0201] The above hard segment ratio can be derived from Equation 6 or Equation 7 below.

[0202] [Formula 6]

[0203]

[0204] In the above equation 6, PA1 is the area of ​​the first peak, PA2 is the area of ​​the second peak, PA3 is the area of ​​the third peak, and PA4 is the area of ​​the fourth peak.

[0205] [Formula 7]

[0206]

[0207] In the above equation 7, PA5 is the area of ​​the fifth peak, PA6 is the area of ​​the sixth peak, PA7 is the area of ​​the seventh peak, and PA8 is the area of ​​the eighth peak.

[0208] The above soft segment ratio can be derived from Equation 8 or Equation 9 below.

[0209] [Formula 8]

[0210]

[0211] In the above equation 8, PA1 is the area of ​​the first peak, PA2 is the area of ​​the second peak, PA3 is the area of ​​the third peak, and PA4 is the area of ​​the fourth peak.

[0212] [Formula 9]

[0213]

[0214] In the above equation 9, the PA5 is the area of ​​the fifth peak, the PA6 is the area of ​​the sixth peak, the PA7 is the area of ​​the seventh peak, and the PA8 is the area of ​​the eighth peak.

[0215] The area of ​​the first peak may be about 0.35 to about 0.6. The area of ​​the first peak may be about 0.4 to about 0.55. The area of ​​the first peak may be about 0.43 to about 0.5. The area of ​​the first peak may be about 0.43 to about 0.52. The area of ​​the first peak may be about 0.45 to about 0.49.

[0216] The area of ​​the second peak may be about 0.37 to about 0.57. The area of ​​the second peak may be about 0.41 to about 0.54. The area of ​​the second peak may be about 0.45 to about 0.53. The area of ​​the second peak may be about 0.45 to about 0.55. The area of ​​the second peak may be about 0.47 to about 0.53.

[0217] The area of ​​the third peak may be about 0.37 to about 0.57. The area of ​​the third peak may be about 0.41 to about 0.54. The area of ​​the third peak may be about 0.45 to about 0.53. The area of ​​the third peak may be about 0.45 to about 0.55. The area of ​​the third peak may be about 0.47 to about 0.53.

[0218] The area of ​​the fourth peak may be about 0.4 to about 0.7. The area of ​​the fourth peak may be about 0.45 to about 0.65. The area of ​​the fourth peak may be about 0.48 to about 0.6. The area of ​​the fourth peak may be about 0.48 to about 0.60. The area of ​​the fourth peak may be about 0.50 to about 0.58.

[0219] The area of ​​the fifth peak may be about 0.35 to about 0.6. The area of ​​the fifth peak may be about 0.4 to about 0.55. The area of ​​the fifth peak may be about 0.43 to about 0.53. The area of ​​the fifth peak may be about 0.43 to about 0.52. The area of ​​the fifth peak may be about 0.45 to about 0.49.

[0220] The area of ​​the sixth peak may be about 0.35 to about 0.6. The area of ​​the sixth peak may be about 0.4 to about 0.55. The area of ​​the sixth peak may be about 0.43 to about 0.5. The area of ​​the sixth peak may be about 0.45 to about 0.55. The area of ​​the sixth peak may be about 0.47 to about 0.53.

[0221] The area of ​​the seventh peak may be about 0.41 to about 0.71. The area of ​​the seventh peak may be about 0.45 to about 0.65. The area of ​​the seventh peak may be about 0.48 to about 0.6. The area of ​​the seventh peak may be about 0.45 to about 0.55. The area of ​​the seventh peak may be about 0.47 to about 0.53.

[0222] The area of ​​the eighth peak may be about 0.4 to about 0.7. The area of ​​the eighth peak may be about 0.45 to about 0.65. The area of ​​the eighth peak may be about 0.48 to about 0.6. The area of ​​the eighth peak may be about 0.48 to about 0.60. The area of ​​the eighth peak may be about 0.50 to about 0.58.

[0223] The area of ​​the tenth peak may be from about 0.7 to about 2.5. The area of ​​the tenth peak may be from 0.75 to about 2. The area of ​​the tenth peak may be from 0.8 to about 1.5. The area of ​​the tenth peak may be from about 1.0 to about 1.15. The area of ​​the tenth peak may be from about 1.02 to about 1.13.

[0224] The area of ​​the eleventh peak may be about 0.7 to about 3.5. The area of ​​the eleventh peak may be about 0.7 to about 3. The area of ​​the eleventh peak may be about 0.8 to about 2.5. The area of ​​the eleventh peak may be about 1.0 to about 1.15. The area of ​​the eleventh peak may be about 1.02 to about 1.13.

[0225] Additionally, the sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may be about 1.49 to about 2.44. The sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may be about 1.81 to about 2.16. The sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may be about 1.9 to about 2.2. The sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may be about 1.95 to about 2.1. Here, the sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may mean the sum of the total number of ester bonds based on the number of terephthalic acids.

[0226] The sum of the area of ​​the second peak and the area of ​​the third peak may be from about 0.95 to about 1.10. The sum of the area of ​​the second peak and the area of ​​the third peak may be from about 0.98 to about 1.07. Here, the sum of the area of ​​the first peak and the area of ​​the third peak may indicate the extent of extension of the molecular bond of the first biodegradable resin.

[0227] The ratio of the area of ​​the fourth peak to the area of ​​the first peak (area of ​​the fourth peak / area of ​​the first peak) may be about 1.1 to about 1.3. The ratio of the area of ​​the fourth peak to the area of ​​the first peak may be about 0.67 to about 2.00. The ratio of the area of ​​the fourth peak to the area of ​​the first peak may be about 0.96 to about 1.40. The ratio of the area of ​​the fourth peak to the area of ​​the first peak may be about 1.15 to about 1.25. The ratio of the area of ​​the fourth peak to the area of ​​the first peak may refer to the ratio of the soft segment to the hard segment within the molecular structure of the first biodegradable resin. That is, the higher the ratio of the area of ​​the fourth peak to the area of ​​the first peak, the softer the first biodegradable resin may have.

[0228] The ratio of the area of ​​the fourth peak to the area of ​​the third peak (area of ​​the fourth peak / area of ​​the third peak) may be from about 0.7 to about 1.89. The ratio of the area of ​​the fourth peak to the area of ​​the third peak may be from about 0.91 to about 1.33. The ratio of the area of ​​the fourth peak to the area of ​​the third peak may be from about 1.0 to about 1.2. The ratio of the area of ​​the fourth peak to the area of ​​the third peak may be from about 1.01 to about 1.1.

[0229] The ratio of the area of ​​the first peak to the area of ​​the second peak (area of ​​the first peak / area of ​​the second peak) may be about 0.61 to about 1.62. The ratio of the area of ​​the first peak to the area of ​​the second peak may be about 0.81 to about 1.11. The ratio of the area of ​​the first peak to the area of ​​the second peak may be about 0.85 to about 0.95. The ratio of the area of ​​the first peak to the area of ​​the second peak may be about 0.86 to about 0.94.

[0230] Additionally, the ratio of the area of ​​the fifth peak to the area of ​​the first peak (area of ​​the fifth peak / area of ​​the first peak) may be from about 0.61 to about 1.71. The ratio of the area of ​​the fifth peak to the area of ​​the first peak may be from about 0.96 to about 1.40. The ratio of the area of ​​the fifth peak to the area of ​​the first peak may be from about 0.8 to about 1.2. The ratio of the area of ​​the fifth peak to the area of ​​the first peak may be from about 0.9 to about 1.1.

[0231] Additionally, the ratio of the area of ​​the sixth peak to the area of ​​the second peak (area of ​​the sixth peak / area of ​​the second peak) may be about 0.58 to about 1.71. The ratio of the area of ​​the sixth peak to the area of ​​the first peak may be about 0.86 to about 1.16. The ratio of the area of ​​the sixth peak to the area of ​​the first peak may be about 0.8 to about 1.2. The ratio of the area of ​​the sixth peak to the area of ​​the first peak may be about 0.9 to about 1.1.

[0232] Additionally, the ratio of the area of ​​the seventh peak to the area of ​​the third peak (area of ​​the seventh peak / area of ​​the third peak) may be from about 0.72 to about 1.92. The ratio of the area of ​​the seventh peak to the area of ​​the third peak may be from about 0.91 to about 1.33. The ratio of the area of ​​the seventh peak to the area of ​​the third peak may be from about 0.8 to about 1.2. The ratio of the area of ​​the seventh peak to the area of ​​the third peak may be from about 0.9 to about 1.1.

[0233] Additionally, the ratio of the area of ​​the eighth peak to the area of ​​the fourth peak (area of ​​the eighth peak / area of ​​the fourth peak) may be about 0.59 to about 1.75. The ratio of the area of ​​the eighth peak to the area of ​​the fourth peak may be about 0.80 to about 1.25. The ratio of the area of ​​the eighth peak to the area of ​​the fourth peak may be about 0.8 to about 1.2. The ratio of the area of ​​the eighth peak to the area of ​​the fourth peak may be about 0.9 to about 1.1.

[0234] Since the first biodegradable resin has the molecular structure described above, the biodegradable buoy according to the present invention can have excellent biodegradability and water decomposition properties while also having improved physical properties.

[0235] In addition, since the first biodegradable resin has the molecular structure described above, the biodegradable buoy according to the present invention can have appropriate mechanical properties and appropriate UV resistance characteristics.

[0236] Since the first biodegradable resin has the molecular structure described above, the biodegradable buoy according to the present invention can have improved mechanical properties.

[0237] Since the first biodegradable resin has the molecular structure described above, the biodegradable buoy according to the present invention can have appropriate UV resistance properties.

[0238] Since the first block and the second block have the above-described characteristics, the biodegradable buoy according to the present invention can have an appropriate biodegradation rate.

[0239] Since the first biodegradable resin has the molecular structure described above, the biodegradable buoy according to the present invention can have an appropriate hydrolysis rate.

[0240] The first biodegradable resin may further comprise a branching agent. The branching agent may comprise at least one selected from the group consisting of trivalent or higher alcohols, anhydrides, and trivalent or higher carboxylic acids. The branching agent may react with the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. Accordingly, the branching agent may be incorporated into the first biodegradable resin as part of its molecular structure.

[0241] The above three or more alcohols may be selected from the group consisting of glycerol, pentaerythritol, and trimethylolpropane.

[0242] The above three or more carboxylic acids are methane tricarboxylic acid, ethanetricarboxylic acid, citric acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzenetricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, At least one alkyl group may be selected from the group consisting of cyclopentane-1,2,3,4-tetracarboxylic acid or benzene-1,2,4,5-tetracarboxylic acid.

[0243] The anhydride may include at least one selected from the group consisting of trimellitic anhydride, succinic anhydride, methylsuccinic anhydride, ethylsuccinic anhydride, 2,3-butanedicarboxylic anhydride, 2,4-pentanedicarboxylic anhydride, 3,5-heptanedicarboxylic anhydride, 1,2,3,4-butanetetracarboxylic anhydride, maleic anhydride, dodecylsuccinic anhydride, or pyromellitic anhydride.

[0244] The branching agent may be included in the first biodegradable resin in an amount of about 0.1 wt% to about 5 wt% based on the entire first biodegradable resin. The branching agent may be included in the first biodegradable resin in an amount of about 0.1 wt% to about 3 wt% based on the entire first biodegradable resin. The branching agent may be included in the first biodegradable resin in an amount of about 0.1 wt% to about 1 wt% based on the entire first biodegradable resin.

[0245] The above first biodegradable resin includes the branching agent within the above range, so that the biodegradable buoy according to the present invention can have appropriate mechanical properties and appropriate biodegradability.

[0246] The first biodegradable resin may further include a polycarbonate diol. The polycarbonate diol may be included in the first biodegradable resin by being bound to the first biodegradable resin in a molecular structure.

[0247] The above polycarbonate diol can be prepared by a dehydration condensation reaction of a carbonate and a polyhydric alcohol. The carbonate can be selected from the group consisting of dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, and ethylene carbonate. The polyhydric alcohol can be selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, 1,6-hexanediol, and 1,2-propanediol.

[0248] The weight average molecular weight of the polycarbonate diol may be from about 500 g / mol to about 5,000 g / mol. The weight average molecular weight of the polycarbonate diol may be from about 700 g / mol to about 4,000 g / mol. The weight average molecular weight of the polycarbonate diol may be from about 800 to about 3,500 g / mol.

[0249] Additionally, the viscosity of the polycarbonate diol may be from about 300 cps to about 20,000 cps. The viscosity of the polycarbonate diol may be from about 400 cps to about 15,000 cps. The viscosity of the polycarbonate diol may be from about 500 cps to about 14,000 cps.

[0250] The OH value of the polycarbonate diol may be from about 20 mgKOH / g to about 350 mgKOH / g. The OH value of the polycarbonate diol may be from about 30 mgKOH / g to about 300 mgKOH / g.

[0251] The polycarbonate diol may be included in the first biodegradable resin in an amount of about 0.1 part by weight to about 5 parts by weight, based on 100 parts by weight of the first biodegradable resin. The polycarbonate diol may be included in the first biodegradable resin in an amount of about 0.5 part by weight to about 3 parts by weight, based on 100 parts by weight of the first biodegradable resin. The polycarbonate diol may be included in the first biodegradable resin in an amount of about 1 part by weight to about 3 parts by weight, based on 100 parts by weight of the first biodegradable resin.

[0252] Since the above polycarbonate diol has the above-described characteristics, the biodegradable buoy according to the present invention can have appropriate wet hardness, appropriate mechanical properties, appropriate solvent resistance, appropriate hydrolysis degree, and appropriate biodegradability.

[0253] The first biodegradable resin may further include a polyether polyol. The polyether polyol may be included in the first biodegradable resin by being bound to the first biodegradable resin in a molecular structure.

[0254] The above polyether polyol can be produced by addition reaction of propylene oxide (PO) or ethylene oxide (EO) with an initiator having two or more activated hydrogens (-OH or NH2). Examples of the above polyether polyol include polypropylene glycol, polyethylene glycol, or polytetramethylene ether glycol.

[0255] The weight average molecular weight of the polyether polyol may be from about 500 g / mol to about 5,000 g / mol. The weight average molecular weight of the polyether polyol may be from about 700 g / mol to about 4,000 g / mol. The weight average molecular weight of the polyether polyol may be from about 800 g / mol to about 3,500 g / mol.

[0256] Additionally, the viscosity of the polyether polyol may be from about 300 cps to about 20,000 cps. The viscosity of the polyether polyol may be from about 400 cps to about 15,000 cps. The viscosity of the polyether polyol may be from about 500 cps to about 14,000 cps.

[0257] The polyether polyol may be included in the first biodegradable resin in an amount of about 0.1 to about 5 parts by weight, based on 100 parts by weight of the first biodegradable resin. The polyether polyol may be included in the first biodegradable resin in an amount of about 0.5 to about 3 parts by weight, based on 100 parts by weight of the first biodegradable resin. The polyether polyol may be included in the first biodegradable resin in an amount of about 1 to about 3 parts by weight, based on 100 parts by weight of the first biodegradable resin.

[0258] Since the above polyether polyol has the above-described characteristics, the biodegradable buoy according to the present invention can have appropriate wet hardness, appropriate mechanical properties, appropriate solvent resistance, appropriate hydrolysis degree, and appropriate biodegradability.

[0259]

[0260] The above biodegradable resin composition may include a second biodegradable resin.

[0261] The second biodegradable resin may be at least one selected from the group consisting of polybutylene succinate, polylactic acid, polybutylene adipate, polybutylene succinate-adipate, polybutylene succinate-terephthalate, polyhydroxybutyrate-valerate, polycaprolactone, polybutylene succinate adipate terephthalate, and thermoplastic starch.

[0262] The second biodegradable resin may include polylactic acid.

[0263] The above polylactic acid may be a high-melting-point polylactic acid having a stereocomplex crystal structure. In addition, the polylactic acid may be formed by solution mixing or melt mixing of poly L-lactic acid and poly D-lactic acid.

[0264] The above polylactic acid may include a unit represented by the following chemical formula 13.

[0265] [Chemical Formula 13]

[0266]

[0267] The polylactic acid may be a polymer comprising L-lactic acid units and / or D-lactic acid units. The polylactic acid may comprise poly L-lactic acid and / or poly D-lactic acid.

[0268] The poly L-lactic acid may be a polymer mainly comprising L-lactic acid units. The poly L-lactic acid may comprise L-lactic acid units in an amount of about 90 mol% to about 100 mol%, about 95 mol% to about 100 mol%, or about 97 mol% to about 100 mol%. The poly L-lactic acid may comprise D-lactic acid units and / or units other than lactic acid. The poly L-lactic acid may comprise the D-lactic acid units and / or units other than lactic acid in an amount of about 0 mol% to about 10 mol%, about 0 mol% to about 5 mol%, or about 0 mol% to about 3 mol%.

[0269] The poly D-lactic acid may be a polymer mainly comprising D-lactic acid units. The poly D-lactic acid may comprise the D-lactic acid units in an amount of about 90 mol% to about 100 mol%, about 95 mol% to about 100 mol%, or about 97 mol% to about 100 mol%. The poly D-lactic acid may comprise the L-lactic acid units and / or units other than lactic acid. The poly D-lactic acid may comprise the L-lactic acid units and / or units other than lactic acid in an amount of about 0 mol% to about 10 mol%, about 0 mol% to about 5 mol%, or about 0 mol% to about 3 mol%.

[0270] Units other than the above lactic acid may be units derived from dicarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, lactones, etc. having functional groups capable of forming two or more ester bonds, and units derived from various polyesters, various polyethers, various polycarbonates, etc. composed of various components of these.

[0271] Examples of the above dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Examples of the above polyhydric alcohols include aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol, or aromatic polyhydric alcohols such as bisphenol with ethylene oxide added thereto.

[0272] Examples of the above hydroxycarboxylic acids include glycolic acid, hydroxybutyric acid, etc. Examples of the lactones include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, δ-valerolactone, etc.

[0273] The polylactic acid may be commercially available from Biomer, Inc. under the name BIOMER® L9000. The polylactic acid may also be commercially available from Natureworks LLC (NATUREWORKS®) or Mitsui Chemical (LACEA®). The polylactic acid may also be described in U.S. Patent Nos. 4,797,468, 5,470,944, 5,770,682, 5,821,327, 5,880,254, and 6,326,458, the entire contents of which are incorporated herein by reference for all purposes.

[0274] The melting point of the polylactic acid may be from about 100°C to about 240°C. The melting point of the polylactic acid may be from about 120°C to about 220°C. The melting point of the polylactic acid may be from about 140°C to about 200°C. The melting point of the polylactic acid may be from about 140°C to about 180°C.

[0275] The crystallization temperature (Tc) of the polylactic acid may be about 50°C to about 80°C. The crystallization temperature (Tc) of the polylactic acid may be about 55°C to about 75°C.

[0276] The glass transition temperature (Tg) of the polylactic acid may be about 20° C. to about 80° C. The glass transition temperature of the polylactic acid may be about 30° C. to about 70° C. The glass transition temperature of the polylactic acid may be about 40° C. to about 65° C. The melting point and the glass transition temperature may be measured by differential scanning calorimetry (DSC) according to ASTM D-3417.

[0277] The polylactic acid has a melting point and glass transition temperature within the above ranges, and thus can be easily extruded. In addition, the biodegradable buoy according to the present invention can have improved mechanical properties because the polylactic acid has a melting point and glass transition temperature within the above ranges.

[0278] The number average molecular weight (Mn) of the polylactic acid may be from about 20,000 g / mol to about 160,000 g / mol. The number average molecular weight of the polylactic acid may be from about 30,000 g / mol to about 140,000 g / mol. The number average molecular weight of the polylactic acid may be from about 40,000 g / mol to about 120,000 g / mol.

[0279] The weight average molecular weight (Mw) of the polylactic acid may be from about 40,000 g / mol to about 200,000 g / mol. The weight average molecular weight of the polylactic acid may be from about 50,000 g / mol to about 180,000 g / mol. The weight average molecular weight of the polylactic acid may be from about 70,000 g / mol to about 160,000 g / mol.

[0280] The polydispersity index (Mw / Mn) of the polylactic acid may be about 1.0 to about 3.0. The polydispersity index of the polylactic acid may be about 1.1 to about 2.0. The polydispersity index of the polylactic acid may be about 1.2 to about 1.8. The weight average molecular weight and the number average molecular weight can be measured by methods known to those skilled in the art. For example, the weight average molecular weight and the number average molecular weight can be measured by gel permeation chromatography (GPC). The weight average molecular weight and the number average molecular weight can be measured by standard monodisperse polystyrene.

[0281] The polylactic acid has a molecular weight and a polydispersity index within the above ranges, and thus can be easily extruded. In addition, the biodegradable buoy according to the present invention can have improved mechanical properties because the polylactic acid has a molecular weight and a polydispersity index within the above ranges.

[0282] The polylactic acid may have an apparent viscosity of about 50 Pa·s to about 600 Pa·s as measured at a temperature of about 190°C and a shear rate of 1,000 / s. The polylactic acid may have an apparent viscosity of about 100 Pa·s to about 500 Pa·s as measured at a temperature of about 190°C and a shear rate of 1,000 / s. The polylactic acid may have an apparent viscosity of about 200 Pa·s to about 400 Pa·s as measured at a temperature of about 190°C and a shear rate of 1,000 / s.

[0283] The polylactic acid may have a melt index of about 3 g / 10 min to about 15 g / 10 min at a temperature of about 190°C. The polylactic acid may have a melt index of about 4 g / 10 min to about 10 g / 10 min at a temperature of about 190°C. The polylactic acid may have a melt index of about 6 g / 10 min to about 10 g / 10 min at a temperature of about 190°C.

[0284] The polylactic acid may have a melt index of about 10 g / 10 min to about 30 g / 10 min at a temperature of about 220°C. The polylactic acid may have a melt index of about 12 g / 10 min to about 25 g / 10 min at a temperature of about 220°C. The polylactic acid may have a melt index of about 15 g / 10 min to about 25 g / 10 min at a temperature of about 220°C.

[0285] The polylactic acid may have a melt index of about 30 g / 10 min to about 60 g / 10 min at a temperature of about 250°C. The polylactic acid may have a melt index of about 35 g / 10 min to about 55 g / 10 min at a temperature of about 250°C. The polylactic acid may have a melt index of about 40 g / 10 min to about 55 g / 10 min at a temperature of about 250°C.

[0286] The polylactic acid has a viscosity and melt index within the above ranges, and thus can be easily extruded. Furthermore, the biodegradable buoy according to the present invention can have improved mechanical properties because the polylactic acid has a viscosity and melt index within the above ranges.

[0287] Preferably, the biodegradable resin composition may include the aforementioned polylactic acid-based resin (PLA) and polybutylene adipate terephthalate-based resin (PBAT). In addition, the biodegradable resin composition may further include an inorganic filler and additives.

[0288] The above inorganic filler may be at least one selected from the group consisting of calcium sulfate, barium sulfate, talc, talc powder, bentonite, kaolin, chalk powder, calcium carbonate, graphite, gypsum, electrically conductive carbon black, calcium chloride, iron oxide, aluminum oxide, potassium oxide, dolomite, silicon dioxide, wollastonite, titanium dioxide, silicate, mica, glass fiber, or mineral fiber.

[0289] Cumulative D in the particle size distribution of the above inorganic filler obtained by laser diffraction method 50 The size may be about 100 ㎛ or less, about 85 ㎛ or less, about 70 ㎛ or less, about 50 ㎛ or less, about 25 ㎛ or less, about 10 ㎛ or less, about 5 ㎛ or less, about 3 ㎛ or less, or about 1 ㎛ or less.

[0290] In addition, the specific surface area of ​​the above-mentioned inorganic filler is about 100 m 2 / g or more. For example, the specific surface area of ​​the above inorganic filler is about 100 m 2 / g or more, about 105 m 2 / g or more or about 110 m 2 / g can be more than that.

[0291] The above-mentioned inorganic filler may be included in the biodegradable resin composition in an amount of less than about 10 parts by weight, less than about 8 parts by weight, or less than about 6 parts by weight, based on 100 parts by weight of the biodegradable resin.

[0292] The above-mentioned inorganic filler may be included in an amount of less than 50,000 ppm, less than 40,000 ppm, or less than 30,000 ppm based on the total weight of the biodegradable resin composition. When the above range is satisfied, the biodegradable buoy can have an appropriate biodegradation rate and an appropriate hydrolysis rate while minimizing weight increase.

[0293] The above additive may include an elongation improver.

[0294] The above-mentioned elongation improving agent may include an oil such as paraffin oil, naphthenic oil or aromatic oil, or an adipate such as dibutyl adipate, diethylhexyl adipate, dioctyl adipate or diisopropyl adipate.

[0295] The elongation improving agent may be included in an amount of about 10 ppm to about 10,000 ppm based on the total weight of the biodegradable resin composition. The elongation improving agent may be included in an amount of about 100 ppm to about 10,000 ppm based on the total weight of the biodegradable resin composition. When the above range is satisfied, the mechanical properties of the biodegradable buoy may be improved.

[0296] The above additive may include a metal salt.

[0297] The metal salt may be included in an amount of about 0.1 ppm to about 1,000 ppm based on the total weight of the biodegradable resin composition. The metal salt may be included in an amount of about 1 ppm to about 500 ppm based on the total weight of the biodegradable resin composition. The metal salt may be included in an amount of about 1 ppm to about 100 ppm based on the total weight of the biodegradable resin composition. The metal salt may be included in an amount of about 1 ppm to about 50 ppm based on the total weight of the biodegradable resin composition. When the above ranges are satisfied, the hydrolysis rate and biodegradation rate of the biodegradable buoy can be appropriately controlled.

[0298] The metal salt may be selected from the group consisting of nitrates, sulfates, hydrochlorides, and carboxylates. The metal salt may be selected from the group consisting of sodium salts, calcium salts, potassium salts, magnesium salts, copper salts, iron salts, aluminum salts, and silver salts. The metal salt may be selected from the group consisting of magnesium acetate, calcium acetate, potassium acetate, copper nitrate, silver nitrate, and sodium nitrate.

[0299] The above additive may include a chain extender.

[0300] The chain extender may include an isocyanate. The chain extender may be selected from the group consisting of monofunctional isocyanates or polyfunctional isocyanates. The chain extender may be selected from the group consisting of tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate and 2,4'-diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and methylenebis(4-isocyanatocyclohexane). The chain extender may include a triisocyanate. The chain extender may include tri(4-isocyanatophenyl)methane.

[0301] The chain extender may be chemically bonded to the biodegradable resin. The chain extender may be chemically bonded to a polymer contained in the biodegradable resin. The chain extender may be bonded to the terminal of a polymer contained in the biodegradable resin. Furthermore, the chain extender may be bonded to the terminals of three polymers contained in the biodegradable resin.

[0302] The chain extender may be included in the biodegradable resin composition in an amount of about 0.1 wt% to about 10 wt% based on the total composition. The chain extender may be included in the biodegradable resin composition in an amount of about 1 wt% to about 8 wt% based on the total composition. The chain extender may be included in the biodegradable resin composition in an amount of about 2 wt% to about 7 wt% based on the total composition. When the above ranges are satisfied, the biodegradable buoy may have appropriate hydrolysis resistance and appropriate biodegradability.

[0303] The above chain extender can also react with terminal carboxyl groups or unreacted carboxyl groups contained in the biodegradable resin composition. Accordingly, the biodegradable resin composition can have a low acid value.

[0304] In addition, the chain extender can couple the polymers contained in the biodegradable resin, thereby increasing the proportion of high molecular weight polymers contained in the biodegradable resin composition. Accordingly, the mechanical properties of the biodegradable buoy can be improved.

[0305] The above additive may include a heat stabilizer. The heat stabilizer may be an antioxidant having an anti-oxidation function. The heat stabilizer may be a phosphorus heat stabilizer. The heat stabilizer may be at least one selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentaamine, triethylphosphonoacetate, phosphoric acid, phosphorous acid, polyphosphric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, or triphenyl phosphine.

[0306] The content of the heat stabilizer may be about 3,000 ppm or less based on the total weight of the biodegradable resin composition. The content of the heat stabilizer may be 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the biodegradable resin composition. When the above range is satisfied, the deterioration of the polymer due to high temperature during the reaction process can be controlled, thereby reducing the terminal groups of the polymer and improving the color.

[0307] The above additives may include UV stabilizers.

[0308] The UV stabilizer may be a hindered amine UV stabilizer. The UV stabilizer may include SUNOVIN 904 from SUNSHOW. The UV stabilizer may have a high molecular weight. The weight average molecular weight of the UV stabilizer may be from about 1,800 g / mol to about 5,000 g / mol. The weight average molecular weight of the UV stabilizer may be from about 2,000 g / mol to about 4,000 g / mol.

[0309] The melting point of the UV stabilizer may be from about 100°C to about 200°C. The melting point of the UV stabilizer may be from about 110°C to about 150°C.

[0310] When thermogravimetric analysis is performed up to a temperature of about 424°C, the volatilization amount of the UV stabilizer may be about 1 wt% or less. In addition, when thermogravimetric analysis is performed up to a temperature of about 424°C, the carbonization amount of the UV stabilizer may be about 0.1 wt% or less.

[0311] The UV stabilizer may be included in the biodegradable polyester resin composition according to an embodiment in an amount of about 0.01 part by weight to about 5 part by weight, based on 100 parts by weight of the biodegradable polyester resin. The UV stabilizer may be included in the biodegradable polyester resin composition according to an embodiment in an amount of about 0.05 part by weight to about 1 part by weight, based on 100 parts by weight of the biodegradable polyester resin. The UV stabilizer may be included in the biodegradable polyester resin composition according to an embodiment in an amount of about 0.1 part by weight to about 0.5 part by weight, based on 100 parts by weight of the biodegradable polyester resin.

[0312] Since the above UV stabilizer has the above-described characteristics, it can be uniformly dispersed in the biodegradable polyester resin composition according to the embodiment.

[0313] Since the above UV stabilizer has the above-described characteristics, it can improve the mechanical properties of the biodegradable polyester resin composition according to the embodiment.

[0314] Since the above UV stabilizer has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have appropriate UV resistance properties.

[0315] Since the above UV stabilizer has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have an appropriate biodegradation rate.

[0316] Since the above UV stabilizer has the above-described characteristics, the biodegradable polyester resin composition according to the embodiment can have an appropriate hydrolysis rate.

[0317] The above biodegradable resin composition may include a reinforcing material.

[0318] The reinforcing material can improve the mechanical properties of the biodegradable resin composition and the biodegradable buoy manufactured therefrom. Furthermore, the reinforcing material can control the deformation characteristics of the biodegradable buoy under ultraviolet rays. Furthermore, the reinforcing material can control the hydrolysis characteristics of the biodegradable buoy. Furthermore, the reinforcing material can control the biodegradability of the biodegradable buoy.

[0319] The reinforcing material may be a fiber derived from biomass. The reinforcing material may be a fiber made of organic material. The reinforcing material may be nanocellulose.

[0320] The above nanocellulose may be at least one selected from the group consisting of nanocrystalline cellulose, cellulose nanofibers, microfibrillated cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, cellulose acetate, methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, pentyl cellulose, hexyl cellulose, and cyclohexyl cellulose.

[0321] The nanocellulose may include an ionically bonded metal. The nanocrystalline cellulose may include sodium element, a sodium carboxylate salt, and the like. In addition, the nanocrystalline cellulose may include a sulfate salt. The nanocrystalline cellulose may be cellulose hydrogen sulfate sodium salt.

[0322] The above nanocellulose can be represented by the following chemical formula 14.

[0323] [Chemical Formula 14]

[0324]

[0325] In the above chemical formula 14, x may be 15 to 35, and y may be 1 to 10.

[0326] The nanocellulose may have a specific surface area of ​​about 200 m2 / g to about 600 m2 / g. The nanocellulose may have a specific surface area of ​​about 300 m2 / g to about 500 m2 / g.

[0327] The weight average molecular weight of the above nanocellulose may be from about 10,000 g / mol to about 40,000 g / mol. The weight average molecular weight of the above nanocrystalline cellulose may be from about 11,000 g / mol to about 35,000 g / mol.

[0328] The moisture content of the nanocrystalline cellulose may be about 2 wt% to about 8 wt%. The moisture content of the nanocrystalline cellulose may be about 4 wt% to about 6 wt%.

[0329] The average diameter of the nanocellulose may be about 0.5 nm to about 10 nm. The average diameter of the nanocellulose may be about 1 nm to about 8 nm. The average diameter of the nanocellulose may be about 1.5 nm to about 7 nm.

[0330] The average length of the above nanocellulose may be from about 20 nm to about 200 nm. The average length of the above nanocellulose may be from about 30 nm to about 180 nm. The average length of the above nanocellulose may be from about 35 nm to about 150 nm. When the diameter and length of the above nanocellulose satisfy the above ranges, the physical properties of the biodegradable resin composition and the biodegradable buoy obtained using the same can be further improved.

[0331] The diameter and length of the above nanocellulose can be measured by atomic force microscopy while dispersed in water.

[0332] The content of the sulfate salt of the nanocellulose may be about 0.6 wt% to about 1.2 wt% based on the entire nanocrystalline cellulose. The content of the sulfate salt of the nanocrystalline cellulose may be about 0.75 wt% to about 1.1 wt% based on the entire nanocellulose.

[0333] The pH of the above nanocellulose may be 5 to 7. The pH of the above nanocellulose may be 6 to 7.

[0334] The zeta potential of the nanocellulose may be about -25 mV to about -50 mV. The zeta potential of the nanocellulose may be about -30 mV to about -45 mV.

[0335] The nanocellulose may be included in an amount of about 0.1 parts by weight to about 2 parts by weight based on 100 parts by weight of the biodegradable resin composition. The nanocellulose may be included in an amount of about 0.3 parts by weight to about 1.5 parts by weight based on 100 parts by weight of the biodegradable resin composition. The nanocellulose may be included in an amount of about 0.5 parts by weight to about 1.2 parts by weight based on 100 parts by weight of the biodegradable resin composition. The nanocellulose may be included in an amount of about 0.6 parts by weight to about 1 part by weight based on 100 parts by weight of the biodegradable resin composition.

[0336] Since the above nanocellulose has the above-described characteristics, it can be uniformly dispersed in the biodegradable resin composition.

[0337] Since the above nanocellulose has the above characteristics, it can improve the mechanical properties of a biodegradable buoy manufactured from the above biodegradable resin composition.

[0338] Since the above nanocellulose has the above characteristics, a biodegradable buoy manufactured from the above biodegradable resin composition can have appropriate UV resistance properties.

[0339] Since the above nanocellulose has the above characteristics, a biodegradable buoy manufactured from the biodegradable resin composition can have an appropriate biodegradation rate.

[0340] Since the above nanocellulose has the above characteristics, a biodegradable buoy manufactured from the above biodegradable resin composition can have an appropriate hydrolysis rate.

[0341] The above biodegradable resin composition may include an oligomer.

[0342] The number average molecular weight of the oligomer may be from about 400 g / mol to about 1,300 g / mol. Based on the total weight of the biodegradable resin composition, the oligomer may be included in an amount of from about 3,000 ppm to about 30,000 ppm. Based on the total weight of the biodegradable resin composition, the oligomer may be included in an amount of from about 5,000 ppm to about 20,000 ppm. Based on the total weight of the biodegradable resin composition, the oligomer may be included in an amount of from about 5,000 ppm to about 15,000 ppm. Based on the total weight of the biodegradable resin composition, the oligomer may be included in an amount of from about 7,000 ppm to about 15,000 ppm.

[0343] The above oligomer may be a reaction product of at least two of the above diol, the above aromatic dicarboxylic acid, and the above aliphatic dicarboxylic acid. The above oligomer may be a reaction product of 1,4-butanediol, terephthalic acid, and adipic acid.

[0344] The above oligomer may include an oligomer in which the molar ratio of the aliphatic dicarboxylic acid is higher than the molar ratio of the aromatic dicarboxylic acid. Among the above oligomers, the ratio of the oligomer containing a relatively larger amount of the aliphatic dicarboxylic acid may be higher than the ratio of the oligomer containing a relatively larger amount of the aromatic dicarboxylic acid.

[0345] The above oligomer can appropriately control the degree of hydrolysis of the biodegradable resin composition. The above oligomer can be a hydrolysis regulator that appropriately controls the degree of hydrolysis of the biodegradable resin composition.

[0346] In addition, the oligomer can appropriately control the biodegradability of the biodegradable resin composition. The oligomer can be a biodegradation regulator that appropriately controls the biodegradability of the biodegradable resin composition.

[0347] The above biodegradable resin composition may contain a plasticizer.

[0348] The plasticizer can impart flexibility to the processability or manufactured biodegradable buoy. The plasticizer can be glycerol, acrylate, glycerin, glycerol monostearate (GMS), sorbitol, or a mixture thereof. The content of the plasticizer can be less than 2.0 wt%, 1.8 wt% or less, 1.6 wt% or less, 1.4 wt% or less, 1.2 wt% or less, or 1.0 wt% or less, based on the total weight of the biodegradable resin composition. When the above range is satisfied, flexibility can be imparted to the biodegradable buoy manufactured from the biodegradable resin composition, and a certain degree of water resistance can be maintained during a typical period of use by the user.

[0349] The above biodegradable resin composition may include a heterogeneous biodegradable resin other than the first biodegradable resin and the second biodegradable resin.

[0350] The above heterogeneous biodegradable resin may be at least one selected from the group consisting of polybutylene azelate terephthalate (PBAzT), polyhydroxybutyrate (PHB), polybutylene succinate (PBS), polybutylene sebacate terephthalate (PBSeT), polybutylene succinate terephthalate (PBST), and polyhydroxyalkanoate (PHA).

[0351] The above heterogeneous biodegradable resin may be included in an amount of about 10 parts by weight to about 100 parts by weight based on 100 parts by weight of the biodegradable resin. The above heterogeneous biodegradable resin may be included in an amount of about 10 parts by weight to about 60 parts by weight based on 100 parts by weight of the biodegradable resin. The above heterogeneous biodegradable resin may be included in an amount of about 20 parts by weight to about 50 parts by weight based on 100 parts by weight of the biodegradable resin. When the above ranges are satisfied, the mechanical, optical, and chemical properties of the biodegradable resin are complemented, so that a biodegradable buoy manufactured from the biodegradable resin composition can have appropriate UV resistance characteristics, an appropriate biodegradation rate, and an appropriate hydrolysis rate.

[0352] The number of carboxyl terminal groups of the biodegradable resin composition may be about 50 eq / ton or less. For example, the number of carboxyl terminal groups of the biodegradable resin composition may be about 50 eq / ton or less, about 48 eq / ton or less, about 45 eq / ton or less, or about 42 eq / ton or less. By controlling the number of carboxyl terminal groups within the above range, when the biodegradable resin composition is extruded and formed into a biodegradable buoy, deterioration can be prevented and improved mechanical properties can be realized.

[0353] The intrinsic viscosity (IV) of the biodegradable resin composition may be about 0.9 dl / g or more. The intrinsic viscosity of the biodegradable resin composition may be about 0.95 dl / g or more, about 1.0 dl / g or more, about 1.1 dl / g or more, about 1.2 dl / g or more, or about 1.3 dl / g or more. The intrinsic viscosity of the biodegradable resin composition may be about 0.95 dl / g to about 1.7 dl / g. The intrinsic viscosity of the biodegradable resin composition may be about 1.3 dl / g to about 1.7 dl / g. The intrinsic viscosity of the biodegradable resin composition may be about 1.4 dl / g to about 1.7 dl / g. By controlling the above-mentioned intrinsic viscosity within the above-mentioned range, the biodegradable resin composition can be smoothly injected, thereby improving the efficiency of the manufacturing process of the biodegradable buoy.

[0354] The biodegradable buoy according to the present invention has a biodegradability of 75% to 97% after 9 weeks and a hydrolysis degree of 35% to 65% after 1 week, as measured by the following measurement method 1.

[0355] [Measurement Method 1]

[0356] The biodegradability after 9 weeks is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm Х 30 mm and placed under compost conditions at a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

[0357] The above compost conditions use Taeheung F&G's composting soil (grade 1 composting by-product fertilizer), and the composition of the composting soil may include 40 wt% pig manure, 15 wt% chicken manure, 37 wt% sawdust, 5 wt% zeolite, and 3 wt% microbial agent.

[0358] The number average molecular weight of the biodegradable resin composition can be measured by gel permeation chromatography (GPC). The equipment and measurement conditions of the gel permeation chromatography (GPC) are not particularly limited, but may be, for example, the following equipment and measurement conditions.

[0359] Sample pretreatment: Dissolve 0.035 mg of the above-mentioned flakes in 1.5 ml of THF.

[0360] Measurement device: Waters, e2695

[0361] Flow rate: 1 ml / min in the above THF

[0362] Injection volume: 50 μl

[0363] Column Temperature: 40 ℃

[0364] Detector: ELSD

[0365] Column: Styragel Column HR 5E, HR4, HR2

[0366] The biodegradability of the biodegradable resin composition measured by the above measurement method 1 after 9 weeks of 75% to 97% is significant as an indicator that the composition can fundamentally solve marine pollution by biodegrading in the ocean or on the beach without generating non-degradable plastics after being used for a typical period of time as a marine buoy. When the above range is satisfied, the composition can function as a marine buoy during the typical period of use as a marine buoy, and biodegradation can be fully achieved after the typical period of use as a marine buoy has elapsed.

[0367] The fact that the biodegradable resin composition measured by the above measurement method 1 has a degree of hydrolysis of 35% to 65% after one week is significant as an indicator that it can maintain a specific appearance and function properly as a marine buoy for a normal period of time even in a harsh environment with high temperature and humidity. When the above range is satisfied, it can function properly as a marine buoy during the normal period of use as a marine buoy, and biodegradation can be fully achieved after the normal period of use as a marine buoy has elapsed.

[0368] In this way, the biodegradable buoy according to the present invention satisfies the biodegradability within a specific period and within a specific range as the first indicator, and the hydrolysis within a specific period and within a specific range as the second indicator, thereby fundamentally solving marine pollution by enabling biodegradation in the ocean or on the beach without generating non-biodegradable plastics, and has the effect of being able to maintain a specific appearance for a typical period of time as a marine buoy and functioning properly even in harsh environments with high temperatures and humidity.

[0369] Preferably, the degree of biodegradation of the biodegradable resin composition after 9 weeks measured by the above measurement method 1 may be 77% to 97%, 79% to 97%, 81% to 97%, 83% to 97%, 85% to 97%, 87% to 97%, or 89% to 97%. The degree of hydrolysis of the biodegradable resin composition after 1 week measured by the above measurement method 1 may be 35% to 63%, 35% to 61%, 35% to 58%, 35% to 55%, 35% to 52%, 35% to 50%, or 35% to 49%. When the above ranges are satisfied, the biodegradable resin composition is environmentally friendly as a marine buoy and has improved water resistance.

[0370] The biodegradable buoy according to the present invention may have a wet hardness reduction rate of 15% or less as measured by the following measurement method 2.

[0371] [Measurement Method 2]

[0372] The above biodegradable resin composition is processed into a biodegradable resin block having a thickness of 2.5 mm and a size of 10 mm X 10 mm, and the initial hardness of the biodegradable resin block and the wet hardness after the biodegradable resin block is immersed in water at 30° C. for 24 hours are measured, and the wet hardness reduction rate is a value obtained by dividing the difference in the wet hardness from the initial hardness by the initial hardness.

[0373] The above hardness can be measured using a Shore hardness measuring device. For example, the Shore D hardness of the biodegradable resin block can be measured using a SAUTER® Digital Professional Shore Hardness Tester.

[0374] The initial Shore D hardness of the biodegradable resin block may be from 30 to 45, from 31 to 44, from 32 to 44, from 35 to 42, or from 35 to 41. The wet Shore D hardness of the biodegradable resin block may be from 28 to 43, from 29 to 41, from 29 to 40, from 30 to 40, or from 30 to 38.

[0375] The fact that the wet hardness reduction rate of the biodegradable resin composition measured by the above measurement method 2 is 15% or less has significance as an indicator that high mechanical properties can be maintained during a normal period of use as a marine buoy.

[0376] Preferably, the wet hardness reduction rate of the biodegradable resin composition measured by the above measurement method 2 may be 14% or less, 13% or less, 12% or less, 11% or less, 5% or more to 14% or less, 6% or more to 14% or less, 7% or more to 14% or less, 8% or more to 14% or less, or 8% or more to 13% or less. When the above range is satisfied, the biodegradable buoy can have excellent biodegradability while maintaining its mechanical properties.

[0377] The biodegradable buoy according to the present invention may have a breaking height of more than 200 cm as measured by the following measuring method 3.

[0378] [Measurement Method 3]

[0379] A 10 kg branch-shaped weight is prepared, and the branch-shaped weight is free-falling from a height of 150 cm to strike the biodegradable buoy, and the branch-shaped weight increases the free-fall height by 10 cm from the height of 150 cm to strike the biodegradable buoy, and the breaking height is the height at which the biodegradable buoy breaks, and the branch-shaped weight is a hemisphere having a lower radius of 63 mm and includes a body portion extending upwards by a length three times the lower radius, and the diameter of the body portion extending upwards gradually decreases, and the diameter at the upper end is 63 mm.

[0380] Fig. 1 is a cross-sectional view of the branch-shaped weight for measuring the breaking height of a biodegradable buoy. Referring to Fig. 1, the branch-shaped weight (10) is a hemisphere (1) having a lower radius (R) of 63 mm, and includes a body (2) extending upwardly (3) with a length three times the lower radius (R), and the diameter of the body (2) extending upwardly (3) gradually decreases, and the diameter at the end of the upper portion (3) is 63 mm, which is the same as the lower radius.

[0381] Before the above-mentioned branch-shaped tip (10) strikes the biodegradable buoy, the biodegradable buoy may be fixed on a metal plate having a thickness of about 2 cm. The striking point of the biodegradable buoy is not particularly limited, but the curved portion with the thinnest thickness may be selected. The fracture of the biodegradable buoy can be confirmed with the naked eye.

[0382] The fact that the breaking height of the biodegradable buoy measured by the above measurement method 3 is greater than 200 cm has significance as an indicator that the eco-friendly buoy can be equipped with impact resistance.

[0383] Preferably, the breaking height of the biodegradable buoy measured by the above measurement method 3 may be 210 cm or more, 220 cm or more, 230 cm or more, 240 cm or more, or more than 200 cm and less than or equal to 300 cm. When the above range is satisfied, the eco-friendly buoy can have excellent biodegradability while meeting the performance of impact resistance.

[0384] The biodegradable buoy according to the present invention may have a first buoyancy maintenance rate of more than 80% as measured by the following measurement method 4.

[0385] [Measurement Method 4]

[0386] The above biodegradable buoy is immersed in seawater at a depth of 5 m at 25°C for 23 hours, and then dried for 1 hour, a process repeated for 60 days, and the first buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 60 days to the initial buoyancy of the biodegradable buoy.

[0387] The buoyancy of the biodegradable buoy can be measured using a buoyancy measuring device. For example, the biodegradable buoy is placed into the buoyancy measuring device filled with water. Then, a pressure device installed in the buoyancy measuring device is used to apply a load to a point 20 cm below the water surface of the water tank. After the biodegradable buoy is left to stand until no air bubbles are generated, the load is measured in increments of 0.1 kgf.

[0388] The above biodegradable buoy can be fixed by a rope at a depth of 5 m in the seawater. The rope can be made of 3-ply yarn, weighs approximately 9.6 kg, and is approximately 10 mm thick.

[0389] The fact that the first buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 4 exceeds 80% is significant as an indicator that it can be equipped with performance as an eco-friendly buoy even in a marine environment where submergence and drying are repeated.

[0390] Preferably, the first buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 4 may be 81% or more, 82% or more, 83% or more, 85% or more, 90% or more, or more than 80% and less than or equal to 95%. When the above range is satisfied, the buoy can function properly as an eco-friendly buoy in a marine environment and have excellent biodegradability.

[0391] The biodegradable buoy according to the present invention may have a second buoyancy maintenance rate of more than 80% as measured by the following measurement method 5.

[0392] [Measurement Method 5]

[0393] The above biodegradable buoy is immersed in warm water at 60°C for 10 hours and then immersed in water at 25°C for 10 hours, and this process is repeated 15 times, and the second buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 15 immersions to the initial buoyancy of the biodegradable buoy.

[0394] The buoyancy of the above biodegradable buoy can be measured by the buoyancy measuring device described above.

[0395] The process of immersing the above biodegradable buoy in warm water at 60°C for 10 hours and in water at 25°C for 10 hours can be carried out using a temperature and humidity chamber.

[0396] The fact that the second buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 5 is over 80% has significance as an indicator that it can be equipped with performance as an eco-friendly buoy even in a marine environment where thermal changes occur.

[0397] Preferably, the second buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 5 may be 81% or more, 83% or more, 85% or more, 87% or more, 90% or more, or more than 80% and less than or equal to 95%. When the above range is satisfied, the buoy can function properly as an eco-friendly buoy in a marine environment and have excellent biodegradability.

[0398] The biodegradable buoy according to the present invention may have a third buoyancy maintenance rate of more than 90% as measured by the following measurement method 6.

[0399] [Measurement Method 6]

[0400] The biodegradable buoy is placed in a high-pressure chamber at 3 atm for 30 minutes, and the third buoyancy retention rate is the ratio of the buoyancy of the biodegradable buoy after being exposed to 3 atm for 30 minutes to the initial buoyancy of the biodegradable buoy.

[0401] The buoyancy of the above biodegradable buoy can be measured by the buoyancy measuring device described above.

[0402] The above high-pressure chamber can be used with a maximum pressure of 50 atm or less. After the biodegradable buoy is placed in the high-pressure chamber, the pressure of the high-pressure chamber can be sequentially increased, and the buoyancy can be measured after maintaining the pressure at 3 atm for 30 minutes.

[0403] The fact that the third buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 6 is over 90% is significant as an indicator that it can be equipped with performance as an eco-friendly buoy even in a marine environment where pressure changes occur.

[0404] Preferably, the third buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 6 may be 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, or more than 90% and less than or equal to 97%. When the above range is satisfied, the buoy can function properly as an eco-friendly buoy in a marine environment and have excellent biodegradability.

[0405] The biodegradable buoy according to the present invention may have a fourth buoyancy maintenance rate of more than 80% as measured by the following measurement method 7.

[0406] [Measurement Method 7]

[0407] The biodegradable buoy is placed between two load-applying plates facing each other, and after a load of 3,000 N is applied, the process of removing the load is repeated 20 times, and the fourth buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after the load application process is repeated 20 times to the initial buoyancy of the biodegradable buoy.

[0408] The buoyancy of the above biodegradable buoy can be measured by the buoyancy measuring device described above.

[0409] Fig. 2 schematically illustrates a method for measuring the fourth buoyancy retention rate of a biodegradable buoy. Referring to Fig. 2, the joint portion (4) of the biodegradable buoy (20) is positioned between two load-applying plates (30) facing each other. The load-applying plates (30) can be subjected to a load of 3,000 N at a pressure rate of 10 mm / min, and then the load can be removed at a rate of 20 mm / min. This process can be performed once, and can be repeated a total of 20 times.

[0410] The fact that the fourth buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 7 is greater than 80% is significant as an indicator that a certain level of durability is met at the joint portion of the biodegradable buoy, and that it can perform as an eco-friendly buoy even in a marine environment.

[0411] Preferably, the fourth buoyancy maintenance rate of the biodegradable buoy measured by the above measurement method 7 may be 81% or more, 82% or more, 83% or more, 90% or more, 95% or more, or more than 80% and less than or equal to 97%. When the above range is satisfied, the buoy can function properly as an eco-friendly buoy in a marine environment and have excellent biodegradability.

[0412] A biodegradable buoy according to the present invention comprises a first ring and a second ring opposite to the first ring, and when the first ring and the second ring are pulled in opposite directions, the breaking strength may exceed 5,000 N.

[0413] Figure 3 schematically illustrates a method for measuring the breaking strength of a biodegradable buoy. Referring to Figure 3, the biodegradable buoy (40) includes a first ring (5) and a second ring (6) opposite to the first ring (5). Here, a rope is hung on the first ring (5) and the second ring (6) so that the first ring (5) and the second ring (6) are pulled in opposite directions, and the strength at which the biodegradable buoy (40), the first ring (5), or the second ring (6) breaks is measured.

[0414] When the first ring and the second ring are tensioned in opposite directions, the breaking strength exceeding 5,000 N is an indicator that a certain level of durability is satisfied in the biodegradable buoy and the tying ring, and that the buoy can perform as an eco-friendly buoy even in a marine environment.

[0415] Preferably, the breaking strength may be 5,100 N or more, 5,300 N or more, 5,500 N or more, 5,700 N or more, or more than 5,000 N and less than or equal to 7,000 N. When the above range is satisfied, the buoy can function properly as an eco-friendly buoy in a marine environment and have excellent biodegradability.

[0416] The above biodegradable resin composition is processed into a biodegradable sheet having a thickness of 300 ㎛ and a size of 10 cm Х 10 cm, and when the biodegradable sheet is irradiated with ultraviolet rays from a UVA 340 ultraviolet lamp at an intensity of 0.75 W / ㎡, the tensile strength reduction rate of the biodegradable sheet from the beginning of the ultraviolet irradiation to 1 day can be 5% to 40%.

[0417] The above tensile strength can be measured using a universal testing machine (UTM, model number 4206-001) from INSTRON. The measurement conditions can be a tensile speed of 100 mm / min and a tensile strength of kgf / ㎟ = 9.8 Mpa.

[0418] The fact that the tensile strength reduction rate of the above biodegradable sheet is 5% to 40% is significant as an indicator that a certain level of mechanical strength can be maintained even under UV, as the buoy is constantly floating on the ocean and is continuously exposed to UV (ultraviolet rays).

[0419] Preferably, the tensile strength reduction rate may be 10% to 40%, 15% to 40%, 20% to 40%, or 20% to 35%. When the above range is satisfied, the reduction in mechanical strength due to UV in a marine environment can be minimized, and excellent biodegradability can be achieved.

[0420] The biodegradable resin composition has a seawater decomposition rate of 5% to 20% after 3 months, and the seawater decomposition rate can be measured at a temperature of 30°C according to ASTM D6691.

[0421] The above seawater decomposition rate can be measured as the aerobic biodegradability of the biodegradable resin composition under seawater conditions in which at least 10 types of aerobic marine microorganisms exist. The aerobic marine microorganisms are not particularly limited and may be general aerobic marine microorganisms that exist in natural seawater. The biodegradable resin composition can be processed into a powder form with an average size of about 25 mm.

[0422] Specifically, after injecting 75 mL of natural seawater into a Respirometry flask, 20 mg of the biodegradable resin composition in powder form is added to the flask. Afterwards, about 100 μl of aerobic marine microorganisms are injected, and the amount of CO2 generated over time is measured using a Respirometer at a temperature of about 30°C to calculate the degree of biodegradation. The degree of biodegradation is calculated by dividing the actual amount of CO2 generated by the biodegradable resin composition by the theoretical amount of CO2 generated by the biodegradable resin composition. 2- It is expressed as a percentage by dividing the value by the amount of occurrence.

[0423] The fact that the biodegradable resin composition has a seawater decomposition rate of 5% to 20% after 3 months, as measured at a temperature of 30°C according to ASTM D6691, is significant as an indicator that a certain degree of biodegradability can be maintained even under environmental conditions of salt and aerobic marine microorganisms, as marine buoys are constantly exposed to salt and aerobic marine microorganisms due to their nature.

[0424] Preferably, the seawater decomposition rate may be 5% to 14%, 6% to 14%, 7% to 14%, or 8% to 14%. When the above range is satisfied, excellent biodegradability can be achieved even under environmental conditions of salinity and aerobic marine microorganisms.

[0425] In addition, the biodegradable resin composition has a seawater decomposition rate of 50% or more after 2 years, and the seawater decomposition rate can be measured at a temperature of 30°C according to ASTM D6691. Preferably, the biodegradable resin composition has a seawater decomposition rate of 50% or more and 60% or less after 2 years, and the seawater decomposition rate can be measured at a temperature of 30°C according to ASTM D6691. When the above range is satisfied, not only can it be used for a period of time normally required as a marine buoy, but it is also biodegradable after use, thereby having the effect of fundamentally solving marine pollution.

[0426]

[0427] <Method for manufacturing biodegradable buoys>

[0428] A method for manufacturing a biodegradable buoy according to the present invention comprises the steps of (a) preparing a biodegradable resin composition, and (b) injecting the biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation of 75% to 97% after 9 weeks, and the degree of hydrolysis of the biodegradable resin composition has a degree of hydrolysis of 35% to 65% after 1 week, and the degree of biodegradation and the degree of hydrolysis are measured by the following measurement method 1.

[0429] [Measurement Method 1]

[0430] The biodegradability after 9 weeks is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 μm and a size of 30 mm Х 30 mm and placed under compost conditions at a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight reduction rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

[0431] The manufacturing method according to the present invention comprises the step of (a) preparing a biodegradable resin composition. The biodegradable resin composition can be manufactured by an apparatus for manufacturing a biodegradable resin composition. Fig. 4 schematically illustrates an apparatus for manufacturing the biodegradable resin composition. Referring to Fig. 4, the apparatus may include a slurry agitator (100), an esterification reaction unit (200), a polycondensation reaction unit (300), a post-treatment unit (400), a first recovery unit (510), and a second recovery unit (520).

[0432] The above step (a) may include a step of preparing a slurry comprising the diol and the aromatic dicarboxylic acid (a-1).

[0433] The above step (a-1) may include a step of mixing and treating the diol and the aromatic dicarboxylic acid. That is, the above step (a-1) may be a pretreatment step prior to the esterification reaction, and may be a step of mixing the diol and the aromatic dicarboxylic acid and forming a slurry therefrom. At this time, the diol may include a biomass-based diol component.

[0434] The above diol and the above aromatic dicarboxylic acid can be introduced into the slurry stirrer (100) and stirred to produce the slurry.

[0435] By mixing and pretreating the above diol and aromatic dicarboxylic acid to form a slurry, not only can the diol and aromatic dicarboxylic acid react uniformly, but it is also effective in rapidly progressing the esterification reaction, thereby increasing the reaction efficiency.

[0436] In particular, when an aromatic dicarboxylic acid, such as terephthalic acid, is completely crystalline and in powder form, its solubility in the diol may be very low, making it difficult for a homogeneous reaction to occur. Therefore, the slurrying pretreatment process can play a very important role in realizing the excellent physical properties of the biodegradable buoy according to the present invention.

[0437] When the aromatic dicarboxylic acid is terephthalic acid, the terephthalic acid is a white crystal that has complete crystallinity and sublimates at around 300°C under normal pressure without a melting point. Since the solubility in the diol is very low, it may be difficult for a homogeneous reaction to occur. Therefore, if a pretreatment process is performed prior to the esterification reaction, the surface area for reacting with the diol within the solid matrix of terephthalic acid can be increased, thereby inducing a homogeneous reaction.

[0438] In addition, when the aromatic dicarboxylic acid is dimethyl terephthalic acid, the dimethyl terephthalic acid can be made into a molten state at about 142°C to 170°C by the pretreatment process and reacted with the diol, so that the esterification reaction rate can proceed more quickly and efficiently.

[0439] Meanwhile, in the pretreatment step of manufacturing the slurry, the structure and properties of the biodegradable resin composition may vary depending on the particle size, particle size distribution, pretreatment reaction conditions, etc. of the aromatic dicarboxylic acid.

[0440] For example, the aromatic dicarboxylic acid may include terephthalic acid. The terephthalic acid may have an average particle diameter (D) measured by a particle size analyzer Microtrac S3500 in the particle size distribution (PSD). 50 ) is 10 ㎛ to 400 ㎛, and the average particle diameter (D 50 ) may be less than or equal to 100. The standard deviation means the square root of the variance. The average particle diameter (D) of the terephthalic acid 50 ) may be 20 ㎛ to 200 ㎛, 30 ㎛ to 180 ㎛, or 50 ㎛ to 150 ㎛. The average particle diameter (D of the terephthalic acid 50 ) If the above range is satisfied, it may be more advantageous in terms of improved solubility and reaction speed for diol.

[0441] In the above pretreatment process, the diol and the aromatic dicarboxylic acid can be mixed and injected into the slurry mixer (100) (tank).

[0442] For example, the slurry agitator (100) may have an anchor type at the lowermost portion and a height of 20 mm or more to the agitator. In addition, having two or more rotating blades may be more advantageous in achieving an efficient agitation effect.

[0443] For example, the slurry stirrer (100) may have a height of 20 mm or more up to the stirrer, i.e., the reactor and the lowest part of the stirrer may be almost in contact, in which case a slurry may be obtained without sedimentation. If the shape, form, and rotating blade of the stirrer do not satisfy the above conditions, when the diol and the aromatic dicarboxylic acid are initially mixed, the aromatic dicarboxylic acid may settle to the bottom, and in this case, phase separation may occur.

[0444] The pretreatment process for preparing the above slurry may include a step of mixing the diol and the aromatic dicarboxylic acid and stirring at about 50 rpm to about 200 rpm at about 30°C to about 100°C for 10 minutes or more, or 10 minutes to 200 minutes.

[0445] The above Dior may have the characteristics described above.

[0446] The above diol may be introduced at once or in separate portions. For example, the above diol may be introduced separately when mixed with the aromatic dicarboxylic acid and when mixed with the aliphatic dicarboxylic acid.

[0447] The above aromatic dicarboxylic acid may have the characteristics described above.

[0448] In the pretreatment step of preparing the slurry, the molar ratio of the diol and the aromatic dicarboxylic acid may be from about 0.8:1 to about 1.2:1. In the pretreatment step of preparing the slurry, the molar ratio of the diol and the aromatic dicarboxylic acid may be from about 0.9:1 to about 1.1:1.

[0449] When the above diol is added in a larger amount than the above aromatic dicarboxylic acid, the above aromatic dicarboxylic acid can be easily dispersed.

[0450] Additionally, additives may be added to the slurry. At least one of the nanocellulose and the metal salt may be added to the slurry.

[0451] The above step (a) may include a step (a-2) of producing a prepolymer by subjecting the slurry and the aliphatic dicarboxylic acid to an esterification reaction.

[0452] The above slurry and the above aliphatic dicarboxylic acid can be reacted in the ester reaction unit (200).

[0453] In the above esterification reaction, the reaction time can be shortened by using the slurry. For example, the slurry obtained in the above pretreatment step can shorten the reaction time of the esterification reaction by 1.5 times or more.

[0454] The above esterification reaction may be performed at least twice. A prepolymer to be introduced into the polycondensation process may be formed through the above esterification reaction.

[0455] For example, the esterification reaction may proceed at once after the aliphatic dicarboxylic acid, or diol, and the aliphatic dicarboxylic acid are introduced into the slurry. That is, the slurry may be introduced into the esterification reactor, and the aliphatic dicarboxylic acid alone or the aliphatic dicarboxylic acid and the diol may be introduced into the esterification reaction unit (200), and the esterification reaction may proceed.

[0456] The esterification reaction may be carried out at about 250°C or lower for about 0.5 to about 5 hours. Specifically, the esterification reaction may be carried out at normal pressure or reduced pressure at about 180°C to about 250°C, about 185°C to about 240°C, or about 200°C to about 240°C until the amount of water as a byproduct theoretically reaches 95%. For example, the esterification reaction may be carried out for, but is not limited to, 0.5 to 5.5 hours, 0.5 to 4.5 hours, or 1 to 4 hours.

[0457] For example, at least one of the polycarbonate diol and the polyether polyol may be mixed in the slurry to allow the first esterification reaction to proceed. Alternatively, at least one of the polycarbonate diol and the polyether polyol may be introduced into the second esterification reaction.

[0458] In addition, after the first ester reaction, a mixture of the aliphatic dicarboxylic acid and the diol may be introduced into the esterification reaction unit (200), and a second ester reaction may proceed together with the first ester reaction product. In addition, at least one of the polycarbonate diol and the polyether polyol may be introduced into the second esterification reaction.

[0459] The first esterification reaction may be performed at 250°C or lower for 1.25 to 4 hours. Specifically, the first esterification reaction may be performed at normal pressure or reduced pressure at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C until the amount of water as a byproduct theoretically reaches 95%. For example, the first esterification reaction may be performed for 1.25 to 4 hours, 1.25 to 3.5 hours, or 2.5 to 3 hours, but is not limited thereto.

[0460] The second esterification reaction may be carried out at about 250°C or less for 0.25 to 3.5 hours. Specifically, the second esterification reaction may be carried out at normal pressure or reduced pressure at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C until the amount of water as a byproduct theoretically reaches 95%. For example, the second esterification reaction may be carried out for 0.5 to 3 hours, 1 to 2.5 hours, or 1.5 to 2.5 hours, but is not limited thereto.

[0461] In the first ester reaction and the second ester reaction, the reaction temperature, reaction time, and the contents of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid introduced are each controlled, so that the number ratio of the first block and the second block, etc. can be controlled. In addition, when the ester reaction is divided into the first ester reaction and the second ester reaction and carried out, the entire ester reaction can be precisely controlled. Accordingly, when the ester reaction is divided and carried out, the reaction stability and reaction uniformity of the ester reaction can be improved.

[0462] Additionally, in the second ester reaction, the branching agent may be additionally introduced. That is, the aliphatic dicarboxylic acid, the mixture of the diol, the branching agent, and the first ester reaction product may react to form the prepolymer. The characteristics and content of the branching agent may be as described above.

[0463] By the above esterification reaction, a prepolymer can be formed.

[0464] The number average molecular weight of the prepolymer may be from about 500 g / mol to about 10,000 g / mol. For example, the number average molecular weight of the prepolymer may be from about 500 g / mol to about 8,500 g / mol, from about 500 g / mol to about 8,000 g / mol, from about 500 g / mol to about 7,000 g / mol, from about 500 g / mol to about 5,000 g / mol, or from about 800 g / mol to about 3,000 g / mol. When the number average molecular weight of the prepolymer satisfies the above range, the molecular weight of the polymer can be efficiently increased in the condensation polymerization reaction.

[0465] The above number average molecular weight can be measured using gel permeation chromatography (GPC). Specifically, the data obtained by gel permeation chromatography includes various items such as Mn, Mw, and Mp, but among these, the molecular weight can be measured based on the number average molecular weight (Mn).

[0466] The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, the metal salt, etc. may be introduced together with the slurry before the esterification reaction. The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, the metal salt, etc. may be introduced into the esterification reaction unit (200) during the esterification reaction. The reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, the metal salt, etc. may be introduced into the esterification reaction product after the esterification reaction. In addition, the reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, the metal salt, etc. may be introduced together with the aliphatic dicarboxylic acid. In addition, the reinforcing material, the branching agent, the polycarbonate diol, the polyether polyol, the metal salt, etc. may be introduced into the esterification reaction unit (200) after the first esterification reaction and before the second esterification reaction.

[0467] Since the reinforcing material and the metal salt are introduced into the esterification reaction, the reinforcing material and the metal salt can be uniformly dispersed within the biodegradable resin.

[0468] The above reinforcing material may have the characteristics described above. In particular, the nanocellulose may be used as the reinforcing material.

[0469] The above nanocellulose may be pretreated by a bead mill or ultrasonic pretreatment before being introduced. Specifically, the above nanocellulose may be water-dispersed nanocellulose that has been pretreated by a bead mill or ultrasonic pretreatment.

[0470] The above bead mill pretreatment can be performed using a vertical or horizontal mill as a wet milling device. A horizontal mill is preferable in that it can accommodate a greater quantity of beads within the chamber, reduces uneven wear on the machine, reduces bead wear, and facilitates easier maintenance, but is not limited thereto.

[0471] The above bead mill pretreatment can be performed using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0472] Specifically, the bead mill pretreatment may be performed using beads having a diameter of about 0.3 mm to about 1 mm. For example, the diameter of the beads may be about 0.3 mm to about 0.9 mm, about 0.4 mm to about 0.8 mm, about 0.45 mm to about 0.7 mm, or about 0.45 mm to about 0.6 mm.

[0473] The dispersibility of nanocellulose can be further improved by ensuring that the diameter of the beads satisfies the above range. If the diameter of the beads exceeds the above range, the average particle size and particle size deviation of nanocellulose may increase, resulting in reduced dispersibility.

[0474] In addition, the bead mill pretreatment is preferably performed using beads having a higher specific gravity than that of nanocellulose, as this allows sufficient energy to be transferred. For example, the beads may be at least one selected from the group consisting of zirconium, zirconium, zirconia, quartz, and aluminum oxide, which have a higher specific gravity than the dispersed nanocellulose. Zirconium beads having a specific gravity at least four times that of the dispersed nanocellulose are preferred, but are not limited thereto.

[0475] In addition, the above ultrasonic pretreatment is a method of physically breaking up or pulverizing nanoparticles by the waves generated by emitting 20 kHz ultrasonic waves into a solution.

[0476] The above ultrasonic pretreatment can be performed for less than 30 minutes at an output of 30,000 J / s or less. For example, the above ultrasonic pretreatment can be performed for less than 25 minutes, less than 20 minutes, or less than 18 minutes at an output of 25,000 J / s or less or 22,000 J / s or less. When the output and the performance time satisfy the above range, the effect of the ultrasonic pretreatment, i.e., the improvement of dispersibility, can be maximized. If the output exceeds the above range, the nanoparticles may re-agglomerate, thereby lowering the dispersibility.

[0477] The above nanocellulose may be bead mill pretreated or ultrasonic pretreated. Alternatively, the nanocellulose may be subjected to both bead mill pretreatment and ultrasonic pretreatment. In this case, ultrasonic pretreatment after bead mill pretreatment is preferable because it prevents reaggregation and improves dispersibility.

[0478] The above nanocellulose may be bead mill pretreated or ultrasonic pretreated. Alternatively, the nanocellulose may be subjected to both bead mill pretreatment and ultrasonic pretreatment. In this case, ultrasonic pretreatment after bead mill pretreatment is preferable because it prevents reaggregation and improves dispersibility.

[0479] Since the nanocellulose contains ionically bonded metals, it can exhibit very high dispersibility in water. Furthermore, through the bead mill pretreatment and ultrasonic pretreatment, an aqueous dispersion with a very high degree of nanocellulose dispersion can be obtained. In the nanocellulose aqueous dispersion, the content of the nanocellulose can be from about 1 wt% to about 50 wt%.

[0480] A titanium-based catalyst and / or a germanium-based catalyst may be used in the above esterification reaction. Specifically, the titanium-based catalyst and / or the germanium-based catalyst may be added to the slurry, and the esterification reaction may proceed.

[0481] Additionally, the titanium-based catalyst and / or the germanium-based catalyst may be added to the slurry before the first esterification reaction, and the titanium-based catalyst and / or the germanium-based catalyst may be further added to the product of the first esterification reaction.

[0482] The biodegradable polyester resin may include at least one titanium-based catalyst 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 at least one germanium-based catalyst selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethylgermanium, tetraethylgermanium, and germanium sulfide.

[0483] In addition, the content of the catalyst may be about 100 ppm to 2,000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. For example, it may include about 100 ppm to about 1,600 ppm, about 150 ppm to about 1,400 ppm, about 200 ppm to about 1,200 ppm, or about 250 ppm to about 1,100 ppm of a titanium-based catalyst or a germanium-based catalyst. When the content of the catalyst satisfies the above range, the physical properties can be further improved.

[0484] In addition, the heat stabilizer may be introduced together with the slurry before the esterification reaction. The heat stabilizer may be introduced into the esterification reaction unit (200) during the esterification reaction. The heat stabilizer may be introduced into the esterification reaction product after the esterification reaction. In addition, the heat stabilizer may be introduced together with the aliphatic dicarboxylic acid. In addition, the heat stabilizer may be introduced into the esterification reaction unit (200) after the first esterification reaction and before the second esterification reaction.

[0485] The characteristics of the above heat stabilizer may be as described above.

[0486] The content of the heat stabilizer may 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 may be 10 ppm to 3,000 ppm, 20 ppm to 2,000 ppm, 20 ppm to 1,500 ppm, or 20 ppm to 1,000 ppm based on the total weight of the diol, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid. When the content of the heat stabilizer satisfies the above range, it is possible to control deterioration of the polymer due to high temperature during the reaction process, thereby reducing the terminal groups of the polymer and improving the color.

[0487] After the esterification reaction is completed, at least one selected from the group consisting of additives such as silica, potassium or magnesium, and color correcting agents such as cobalt acetate may be further added to the esterification reaction product. That is, after the esterification reaction is completed, the additive and / or color correcting agent may be added, stabilized, and then a polycondensation reaction may proceed. The additive and / or the color correcting agent may be added after the esterification reaction is completed and introduced into the polycondensation reaction unit (300) together with the prepolymer. Accordingly, the additive and / or the color correcting agent may be uniformly dispersed in the biodegradable resin.

[0488] In addition, after the esterification reaction is completed, the inorganic filler may be added to the esterification reaction product. That is, after the esterification reaction is completed, the inorganic filler is introduced and stabilized, and then the condensation polymerization reaction may proceed. The characteristics of the inorganic filler are as described above. The inorganic filler may be introduced into the condensation polymerization reaction unit (300) together with the prepolymer, and the condensation polymerization process may proceed. Accordingly, the inorganic filler may be uniformly dispersed in the biodegradable resin.

[0489] In addition, the first recovery unit (510) can recover reaction by-products such as water from the esterification reaction unit (200). The first recovery unit (510) can recover by-products generated in the esterification reaction by applying vacuum pressure to the esterification reaction unit (200) or performing reflux.

[0490] The above step (a) may include the step (a-3) of subjecting the prepolymer to a polycondensation reaction. The polycondensation reaction may proceed as follows.

[0491] The above prepolymer may be introduced into the polycondensation reaction unit (300). In addition, at least one of the reinforcing material, the heat stabilizer, the color corrector, the inorganic filler, the metal salt, or other additives may be introduced into the polycondensation reaction unit (300) together with the prepolymer.

[0492] Thereafter, the polycondensation reaction can be carried out at about 180° C. to about 280° C. and about 10 torr or less for about 1 hour to about 5 hours. For example, the polycondensation reaction can be carried out at about 190° C. to about 270° C., about 210° C. to about 260° C., or about 230° C. to about 255° C., and can be carried out at about 0.9 torr or less, about 0.7 torr or less, about 0.2 torr to about 10 torr, about 0.3 torr to about 0.9 torr, or about 0.4 torr to about 0.6 torr, and can be carried out for about 1.5 hours to about 5 hours, about 2 hours to about 4.5 hours, or about 2 hours to about 4 hours.

[0493] Additionally, the polycondensation reaction may include a first polycondensation reaction and a second polycondensation reaction.

[0494] 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 hour to about 3.5 hours, about 0.5 hour to about 3.0 hours, or about 0.5 hour to about 2.8 hours.

[0495] Additionally, the secondary polycondensation may 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 0.3 torr to about 0.8 torr, or about 0.4 torr to about 0.6 torr, for about 0.5 hour to about 4 hours, about 1 hour to about 3.5 hours, or about 1.5 hour to about 3.5 hours.

[0496] In addition, a titanium-based catalyst or a germanium-based catalyst may be further added to the prepolymer before the polycondensation reaction. In addition, at least one selected from the group consisting of an additive such as silica, potassium, or magnesium; an amine-based stabilizer such as trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, phosphorous acid, or tetraethylene pentamine; and a polymerization catalyst such as antimony trioxide, antimony trioxide, or tetrabutyl titanate may be additionally added to the prepolymer before the polycondensation reaction.

[0497] The number average molecular weight of the polymer may be about 40,000 g / mol or greater. For example, the number average molecular weight of the polymer may be about 43,000 g / mol or greater, about 45,000 g / mol or greater, or about 50,000 g / mol to about 70,000 g / mol. When the number average molecular weight of the polymer satisfies the above range, the physical properties, impact resistance, durability, and formability can be further improved.

[0498] In addition, the second recovery unit (520) can recover reaction by-products such as water from the polycondensation reaction unit (300). The second recovery unit (520) can apply vacuum pressure to the polycondensation reaction unit (300) and recover by-products generated in the polycondensation reaction.

[0499] The second recovery unit (520) can apply a vacuum pressure of about 0.1 torr to about 1 torr to the inside of the polycondensation reaction unit (300). The second recovery unit (520) can apply a vacuum pressure of about 0.1 torr to about 0.9 torr to the inside of the polycondensation reaction unit (300).

[0500] Thereafter, the hydrolysis-resistant agent and / or the chain extender may be added to the polymer. Thereafter, the polymer, the hydrolysis-resistant agent, and the chain extender may be uniformly mixed and maintained at a temperature of about 200°C to about 260°C for about 1 minute to about 15 minutes. Accordingly, the polymer may react with the hydrolysis-resistant agent and / or the chain extender.

[0501] The characteristics of the above chain extender are as described above.

[0502] The above step (a) may include a step of (a-4) producing pellets from the polymer.

[0503] Specifically, after cooling the polymer to about 15°C or less, about 10°C or less, or about 6°C or less, the cooled polymer can be cut to produce pellets.

[0504] The above cutting step can be performed using any pellet cutting machine used in the art without limitation, and the pellets can have various shapes. The method for cutting the pellets can be an underwater cutting method or a strand cutting method.

[0505] The above pellets may undergo additional post-processing. The pellets may be fed into the post-processing unit (400) to undergo the post-processing process.

[0506] The above post-processing process may be performed within the post-processing unit (400). The pellets may be introduced into the post-processing unit (400). Thereafter, the post-processing unit (400) may melt the introduced pellets through frictional heat and re-extrude them. That is, the post-processing unit (400) may include an extruder, such as a twin-screw extruder.

[0507] The temperature of the above post-treatment process may be about 230°C to about 270°C. The temperature of the above post-treatment process may be about 230°C to about 260°C. The temperature of the above post-treatment process may be about 240°C to about 265°C. The temperature of the above post-treatment process may be about 240°C to about 260°C.

[0508] The post-treatment process time may be about 30 seconds to about 3 minutes. The post-treatment process time may be about 50 seconds to about 2 minutes. The post-treatment process time may be about 1 minute to about 2 minutes.

[0509] Thereafter, the resin extruded by the extruder can be cooled, cut, and processed into post-processed pellets. That is, the resin extruded from the extruder can be reprocessed into pellets through the cutting step described above.

[0510] The crystallinity of the pellets can be improved through the post-treatment process. Furthermore, the content of residual substances contained in the pellets can be controlled through the post-treatment process. In particular, the content of oligomers contained in the pellets can be controlled through the post-treatment process. The content of residual solvent contained in the pellets can be controlled through the post-treatment process.

[0511] Accordingly, the post-treatment process can appropriately control the mechanical properties, biodegradability, UV resistance, optical properties, or hydrolysis resistance of the biodegradable resin composition.

[0512] After the pellets are manufactured, the biodegradable resin may be compounded with the heterogeneous biodegradable resin. Additionally, at least one of the inorganic filler, the light stabilizer, the color corrector, or other additives may be compounded with the biodegradable resin and the heterogeneous biodegradable resin.

[0513] The above compounding process may be as follows.

[0514] The biodegradable resin and the heterogeneous biodegradable resin may be mixed with at least one of the inorganic filler, the heat stabilizer, the color corrector, the metal salt, or the other additives, and fed into an extruder. The mixed biodegradable resin composition may be melted at a temperature of about 180°C to about 260°C in the extruder and mixed with each other. Thereafter, the melted and mixed biodegradable resin composition may be extruded, cooled, cut, and re-palletized. Through this process, the biodegradable resin composition according to the present invention may be manufactured by complexing with the heterogeneous biodegradable resin.

[0515] Alternatively, the inorganic filler, the heat stabilizer, the color corrector, the metal salt and the other additives may be added during the process of polymerizing the biodegradable resin.

[0516] The manufacturing method according to the present invention comprises the step of (b) injecting the biodegradable resin composition, wherein the biodegradable resin composition has a degree of biodegradation after 9 weeks of 75% to 97% as measured by the above measurement method 1, and the biodegradable resin composition has a degree of hydrolysis after 1 week of 35% to 65%.

[0517] Figure 5 schematically illustrates a process for manufacturing a biodegradable buoy from the biodegradable resin composition prepared in step (a). The process for manufacturing the biodegradable buoy from the biodegradable resin composition can be performed by extrusion blow molding.

[0518] Specifically, referring to FIG. 5, the step (b) may include a process (b-1) of closing the blow mold (50) after the biodegradable resin composition (7) is injected from the extruder (8) onto the blow mold (50).

[0519] The biodegradable resin composition (7) has a biodegradability of 75% to 97% after 9 weeks, as measured by the aforementioned measurement method 1, and the biodegradable resin composition has a hydrolysis degree of 35% to 65% after 1 week.

[0520] The above biodegradable resin composition (7) can be manufactured using the above biodegradable resin pellets.

[0521] The temperature of the biodegradable resin composition (7) extruded from the extruder (8) may be from about 180°C to about 240°C, from about 180°C to about 230°C, from about 180°C to about 220°C, or from about 190°C to about 220°C. In the extrusion blow molding method, stable molding of the parison is important before the blowing process is performed. When the above range is satisfied, the sagging phenomenon of the biodegradable resin composition (7) due to a decrease in melt strength can be suppressed, and the parison molding can be made more uniform.

[0522] The biodegradable resin composition (7) may be injected in the direction between the axes along which the blow mold (50) moves. In addition, after injection of the biodegradable resin composition (7) onto the blow mold (50) is completed, a process of closing the blow mold (50) (mold closing process) may be performed.

[0523] The temperature of the blow mold (50) may be 20°C or less, 19°C or less, 18°C ​​or less, 17°C or less, 16°C or less, or 15°C or less. When the above range is satisfied, the adhesion between the biodegradable resin composition (7) and the blow mold (50) is improved, enabling stable molding.

[0524] The above step (b) may include a blowing process of injecting air (9) into the biodegradable resin composition (7) (b-2).

[0525] The above blowing process can be performed at a pressure of about 3 kgf / cm2 to about 6 kgf / cm2, about 3.5 kgf / cm2 to about 6 kgf / cm2, about 3.5 kgf / cm2 to about 5 kgf / cm2, or about 3.5 kgf / cm2 to about 4.5 kgf / cm2. When the above range is satisfied, stable molding of the biodegradable resin composition (7) is possible.

[0526] The step (b) above may include a process (b-3) of cooling the biodegradable resin composition (7) after the injection of air into it is completed, cutting the molded biodegradable resin composition, and then opening the blown mold (50) (mold opening process).

[0527] The above cooling time may be 60 seconds or less, 50 seconds or less, 40 seconds or less, 30 seconds or less, or 27 seconds or less. When the above range is satisfied, the molded biodegradable resin composition may have a uniform thickness, and the productivity of the biodegradable buoy may be improved.

[0528] The above cooling time refers to the time the biodegradable resin composition (7) is kept in the blown mold (50) to cool after the blown process.

[0529] After the cooling process, the molded biodegradable resin composition may be cut (11) and a process of opening the blown mold (50) may be performed. The method of cutting the molded biodegradable resin composition is not particularly limited. The molded biodegradable resin composition may be naturally cooled in the air after being removed from the blown mold (50).

[0530] The above step (b) may include a process of (b-4) removing a biodegradable buoy (60) formed from the biodegradable resin composition from the blown mold (50).

[0531] The size of the biodegradable buoy is not particularly limited, but the length of the biodegradable buoy may be 800 cm to 1,400 cm, 800 cm to 1,300 cm, 800 cm to 1,200 cm, 900 cm to 1,200 cm, 950 cm to 1,200 cm, and preferably 1,150 cm.

[0532] The height of the biodegradable buoy may be 300 cm to 900 cm, 400 cm to 900 cm, 400 cm to 800 cm, 500 cm to 800 cm, 500 cm to 700 cm, and preferably 660 cm.

[0533]

[0534] Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely illustrative examples for further explaining the present invention, and the present invention is not limited to the following examples and comparative examples.

[0535]

[0536] Manufacturing example

[0537] <Manufacture of pretreated nanocellulose>

[0538] Cellulose nanocrystals (NVC-100, manufacturer: Celluforce) in the form of dry powder having a particle size of about 1 ㎛ to about 50 ㎛ were dispersed in water at 1 wt%, and then ultrasonicated for 1 minute at an output of 20,000 J / s using a tip-type ultrasonic disperser to produce pretreated nanocellulose.

[0539]

[0540] <PBAT 수지의 제조>

[0541] 1. Preparation of PBAT resin #1

[0542] - Step 1: Preprocessing to obtain slurry

[0543] In the absence of a catalyst, the pretreated nanocellulose, iron (II) acetate, 1,4-butanediol (1,4-BDO) and terephthalic acid (TPA) according to the above manufacturing example were mixed and placed in a slurry tank (the lowermost part of the slurry tank was anchor type, 40 mm in height to the agitator, and equipped with three rotating blades). At this time, the molar ratio of the 1,4-butanediol (1,4-BDO) and terephthalic acid (TPA) was 1.4:1, and the D of the terephthalic acid (TPA) 50 was 130 μm. The mixture introduced into the slurry tank was pretreated by stirring at 60°C and 100 rpm for 1 hour, and a slurry was obtained without phase separation. The contents of the pretreated nanocellulose and the iron (II) acetate are shown in Table 1 below.

[0544] - Step 2: Obtaining a prepolymer

[0545] The slurry obtained in the first step was fed into a reactor through a supply line, and 250 ppm of tetrabutyl titanate (Dupont, Tyzor TnBT product), a titanium-based catalyst, was fed into the reactor based on the total weight of the slurry, and then the first esterification reaction was performed at 220°C and atmospheric pressure for about 1 hour and 30 minutes until 95% of the by-product water was discharged.

[0546] 53 mol% of 1,4-butanediol (1,4-BDO) based on the total mole number of diol components was added to the above first esterification reaction product, 53 mol% of adipic acid (AA) based on the total mole number of dicarboxylic acid components was added, 200 ppm of tetrabutyl titanate (Dupont, Tyzor TnBT product), a titanium-based catalyst, was added based on the total weight of diol components and dicarboxylic acid components, and polycarbonate diol was added. The content of the polycarbonate diol is shown in Table 1 below. Thereafter, a second esterification reaction was performed at 220°C and atmospheric pressure for about 2 hours and 30 minutes until 95% of the by-product water was discharged, thereby producing a prepolymer having a number average molecular weight of 1,500 g / mol.

[0547] - Step 3: Polycondensation reaction step

[0548] Based on the total weight of the prepolymer obtained in the second step, 400 ppm of a titanium-based catalyst, tetrabutyl titanate (Dupont, Tyzor TnBT product) and 500 ppm of a triethylene phosphate stabilizer were added, and the mixture was stabilized for approximately 10 minutes. Thereafter, the temperature was raised to 240°C and a polycondensation reaction was performed at 0.5 torr for 4 hours to produce a polymer having a number-average molecular weight of 55,000 g / mol.

[0549] Thereafter, 1 part by weight of a hydrolysis inhibitor based on 100 parts by weight of the polymer manufactured above was added to the polymer. Thereafter, the polymer was subjected to a terminal extension reaction at a temperature of about 240°C for about 10 minutes, and then cooled to 5°C. Thereafter, the polymer was cut with a pellet cutter to obtain PBAT resin #1 pellets.

[0550] 2. Preparation of PBAT resins #2 to #4

[0551] Except for the components and contents shown in Table 1 below, PBAT resin #2 to #4 pellets were manufactured by the same process as the manufacturing process of PBAT resin #1.

[0552]

[0553] Category 1,4-BDO 1) TPA 2) AA 3) CNC 4) metal salts 5) Polycarbonate diol hydrolysis agent unit mol %ppm 6) Weight division 7) Weight division 8) PBAT Resin #1120475370010010.1PBAT Resin #21204753700100-0.1PBAT Resin #31205050700-1-PBAT Resin #41204852700100--1) 1,4-BDO: 1,4-butanediol2) TPA: terephthalic acid3) AA: adipic acid4) CNC: pretreated nanocellulose5) Metal salt: iron(II) acetate6) ppm: based on the total weight of 1,4-BDO, TPA and AA7) Parts by weight: based on 100 parts by weight of the total of 1,4-BDO, TPA and AA8) Parts by weight: based on 100 parts by weight of the polymer

[0554]

[0555] <Manufacture of biodegradable resin composition>

[0556] 1. Preparation of biodegradable resin composition #1

[0557] A raw material composition was prepared with the components and contents shown in Table 2 below. Thereafter, the raw material composition was fed into a T-die extrusion molding device (φ20 mm, L / D=25) manufactured by Toyo Seiki Seisaku-sho, Ltd. and equipped with a twin screw, and kneaded at a temperature of 155°C to produce a pelletized biodegradable resin composition #1.

[0558] 2. Preparation of biodegradable resin compositions #2 to #11

[0559] Except for the components and contents shown in Table 2 below, biodegradable resin compositions #2 to #11 pellets were manufactured by the same process as the manufacturing process of biodegradable resin composition #1.

[0560]

[0561] ClassificationPBATPLA 1) PHB 2) calcium carbonate 3) plasticizer 4) Antioxidants 5) chain extender 6)Unit weight % Biodegradable resin composition #1PBAT resin #1 1070181.2-0.50.3 Biodegradable resin composition #2PBAT resin #1 1565171.70.50.50.3 Biodegradable resin composition #3PBAT resin #2 10601514.2-0.50.3 Biodegradable resin composition #4PBAT resin #2 15551018.50.50.50.5 Biodegradable resin composition #5PBAT resin #3 540549-0.50.5 Biodegradable resin composition #6PBAT resin #3 15401528.50.50.50.5 Biodegradable resin composition #7PBAT resin #2 3060-8.8-0.50.7 Biodegradable resin composition #8PBAT resin #2 4050-8.30.50.50.7 Biodegradable resin composition #9-100----- Biodegradable resin composition #10 PBAT resin #1 70-254-0.50.5 Biodegradable resin composition #11 PBAT resin #1 6010254-0.50.51) PLA: Nature Works, 4032D2) PHB: TianAn ENMAT Y30003) Calcium carbonate: Heavy calcium carbonate (average particle size 2.2 ㎛, BET surface area 1.0 ㎡ / g, roundness 0.85)4) Plasticizer: Acetylated monoglyceride, Biocizer5) Antioxidant: Phenolic antioxidant, AO-606) Chain extender: BASF, Joncryl

[0562]

[0563] Example

[0564] Example 1

[0565] After the biodegradable resin composition #1 above was melted at a temperature of about 210°C, the melted biodegradable resin composition #1 was blown into a mold at a pressure of about 5 kgf / cm2. Thereafter, it was cooled for about 20 seconds to produce a biodegradable buoy. The mold temperature was about 13°C, and the biodegradable buoy had a capsule shape with a length of 1,150 cm and a height of about 660 cm.

[0566] Examples 2 to 8 and Comparative Examples 1 to 3

[0567] A biodegradable buoy was manufactured by the same process as Example 1, except that the biodegradable resin composition shown in Table 3 below was used and the melting temperature, blow pressure, and cooling time were changed.

[0568]

[0569] Classification Biodegradable resin composition Melting temperature Blow pressure Cooling time Unit -℃ kgf / ㎠ Sec Example 1 Biodegradable resin composition #1 210520 Example 2 Biodegradable resin composition #2 210420 Example 3 Biodegradable resin composition #3 220520 Example 4 Biodegradable resin composition #4 220415 Example 5 Biodegradable resin composition #5 200525 Example 6 Biodegradable resin composition #6 200415 Example 7 Biodegradable resin composition #7 210525 Example 8 Biodegradable resin composition #8 210415 Comparative example 1 Biodegradable resin composition #9 210520 Comparative example 2 Biodegradable resin composition #10 21055 Comparative example 3 Biodegradable resin composition #11 21055

[0570]

[0571] Experimental example

[0572] Experimental Example 1 - Biodegradability Test

[0573] Each of the biodegradable resin compositions #1 to #11 was manufactured into flakes having a thickness of 300 μm and a size of 30 mm 30 mm, and the initial number average molecular weight of the flakes was measured under the following gel permeation chromatography (GPC) equipment and measurement conditions.

[0574] Afterwards, each of the above flakes was placed under the following compost conditions, temperature 60°C and humidity 90%, for 63 days, and then the number average molecular weight was measured under the equipment and measurement conditions of gel permeation chromatography (GPC) below. The value of the difference between the initial number average molecular weight and the number average molecular weight after 63 days was divided by the initial number average molecular weight to derive the biodegradability, and the results are shown in Table 4 below.

[0575] - Equipment and measurement conditions for gel permeation chromatography (GPC)

[0576] Sample pretreatment: Dissolve 0.035 mg of the above-mentioned flakes in 1.5 ml of THF.

[0577] Measurement device: Waters, e2695

[0578] Flow rate: 1 ml / min in the above THF

[0579] Injection volume: 50 μl

[0580] Column Temperature: 40 ℃

[0581] Detector: ELSD

[0582] Column: Styragel Column HR 5E, HR4, HR2

[0583] - Compost conditions

[0584] Manufacturer: Taeheung F&G

[0585] Product Name: Jisengto (Grade 1 compost, byproduct fertilizer)

[0586] Compost composition: 40 wt% pig manure, 15 wt% chicken manure, 37 wt% sawdust, 5 wt% zeolite, 3 wt% microbial agent

[0587] Experimental Example 2 - Hydrolysis Test

[0588] The initial number average molecular weight of each flake manufactured in the above Experimental Example 1 was measured under the equipment and measurement conditions of gel permeation chromatography (GPC) of the above Experimental Example 1.

[0589] Afterwards, 5 g of each of the above flakes was added to 500 mL of deionized water, sealed with a stopper to prevent the deionized water from evaporating, and placed in a convection (hot air) oven at 80°C for 7 days. The humidity environment is the same as that at 100% RH because it is immersed in deionized water.

[0590] Thereafter, the number average molecular weight was measured under the equipment and measurement conditions of the gel permeation chromatography (GPC) described above. The difference between the initial number average molecular weight and the number average molecular weight after 7 days was divided by the initial number average molecular weight to derive the degree of hydrolysis, and the results are shown in Table 4 below.

[0591] Experimental Example 3 - Wet Hardness Reduction Rate Test

[0592] After preparing two Teflon sheets, a stainless steel (SUS) frame (area of ​​12 cm Х 12 cm) was placed on one Teflon sheet, and about 57 g of each of the biodegradable resin compositions #1 to #11 was placed into the stainless steel (SUS) frame (area of ​​12 cm Х 12 cm), covered with another Teflon sheet, and placed in the center of a hot press (Hot Press, manufacturer: With Lab, model name: WL 1600SA) having an area of ​​about 25 cm Х 25 cm. Thereafter, about 57 g of each of the biodegradable resin compositions #1 to #11 was maintained at 210°C and under a pressure of 10 Mpa for about 3 minutes, and then desorbed and cooled in water at about 20°C for about 30 seconds, thereby manufacturing a block having an area of ​​about 10 cm Х 10 cm and a thickness of about 2.5 mm.

[0593] The Shore D initial hardness of each block was measured using a Shore hardness measuring device (SAUTER® Digital Professional Shore Hardness Tester). Then, each block was cut into a size of about 3 cm Х 3 cm and immersed in water at a temperature of about 30°C for about 24 hours. Thereafter, after removing moisture from each block, the Shore D hardness was measured using the Shore hardness measuring device. The difference between the Shore D initial hardness and the Shore D hardness was divided by the Shore D initial hardness to derive the wet hardness reduction rate, and the results are shown in Table 4 below.

[0594] Experimental Example 4 - UV Resistance Test

[0595] After preparing two Teflon sheets, a stainless steel (SUS) frame (area of ​​12 cm Х 12 cm) was placed on one Teflon sheet, and about 7 g of each of the biodegradable resin compositions #1 to #11 was placed into the stainless steel (SUS) frame (area of ​​12 cm Х 12 cm), covered with another Teflon sheet, and placed in the center of a hot press (Hot Press, manufacturer: With Lab, model name: WL 1600SA) having an area of ​​about 25 cm Х 25 cm. Thereafter, about 7 g of each of the biodegradable resin compositions #1 to #11 was maintained at 210°C and under a pressure of 10 Mpa for about 3 minutes, then desorbed, and cooled in water at about 20°C for about 30 seconds, whereby a sheet having an area of ​​about 10 cm Х 10 cm and a thickness of about 300 ㎛ was manufactured.

[0596] The initial tensile strength of each sheet was measured using a universal testing machine (UTM, model number 4206-001) from INSTRON (tensile speed 100 mm / min, tensile strength kgf / ㎟ = 9.8 Mpa). Afterwards, the sheets were irradiated with UV rays from a UVA 340 UV lamp at an intensity of approximately 0.75 W / ㎡ for 1 day, and then the tensile strength was measured using the universal testing machine. The difference between the initial tensile strength and the tensile strength was divided by the initial tensile strength to derive the tensile strength reduction rate, and the results are shown in Table 4 below.

[0597] Experimental Example 5 - Seawater Decomposition Test

[0598] Each of the above biodegradable resin compositions #1 to #11 was processed into a 25 mm powder form. After injecting 75 mL of natural seawater into a respirometry flask, 20 mg of each biodegradable resin composition in powder form was added to the flask. Afterwards, about 100 ㎕ of aerobic marine microorganisms were injected, and the flask was maintained at a temperature of about 30 ℃ for 3 months using a respirometer. Thereafter, the CO2 generation amount of the biodegradable resin composition was measured. The seawater decomposition degree was determined based on ASTM D6691, and the actual CO2 generation amount of the biodegradable resin composition was divided into the theoretical CO2 generation amount of the biodegradable resin composition. 2- The value divided by the amount of occurrence is expressed as a percentage, and the results are shown in Table 4 below.

[0599]

[0600] ClassificationBiodegradabilityHydrolysisWet hardness reduction rateTensile strength reduction rateSeawater degradabilityUnit%Biodegradable resin composition #19038102511Biodegradable resin composition #29147102315Biodegradable resin composition #39142102413Biodegradable resin composition #4924792414Biodegradable resin composition #5903992210.5Biodegradable resin composition #6905192318Biodegradable resin composition #79361113219.1Biodegradable resin composition #89362123018.8Biodegradable resin composition #9702125553Biodegradable resin composition #109372456519.9Biodegradable resin composition #119170236719.2

[0601]

[0602] Experimental Example 6 - Buoyancy Test

[0603] The volume and weight of each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 were measured. Thereafter, each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 was placed into the buoyancy measuring device filled with a water tank. Thereafter, a load was applied to a point 20 cm below the water surface of the water tank using a pressurizing device installed in the buoyancy measuring device. Thereafter, each biodegradable buoy was left to stand until no air bubbles were generated, and the load was measured in units of 0.1 kgf, and evaluated according to the following criteria. The results are shown in Table 5 below.

[0604] Eligibility: The measured buoyancy of the biodegradable buoy ≥ [(volume of the biodegradable buoy × 0.7) - (weight of the biodegradable buoy)]

[0605] Ineligible: The measured buoyancy of the biodegradable buoy < [(volume of the biodegradable buoy × 0.7) - (weight of the biodegradable buoy)]

[0606] Experimental Example 7 - Buoyancy Maintenance Evaluation #1 <Marine Environmental Exposure Test>

[0607] The initial buoyancy of each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 was measured according to Experimental Example 6. Thereafter, using a rope (3-ply yarn, weight approximately 9.6 kg, thickness approximately 10 mm), each biodegradable buoy was immersed in seawater at 25°C for 23 hours at a depth of 5 m, and then dried for 1 hour. This process was repeated for 60 days. Thereafter, the buoyancy of each biodegradable buoy was measured and evaluated according to the following criteria. The results are shown in Table 5 below.

[0608] Eligibility: The ratio of the buoyancy of the biodegradable buoy after 60 days to the initial buoyancy of the biodegradable buoy is greater than 80%.

[0609] Ineligible: The ratio of the buoyancy of the biodegradable buoy after 60 days to the initial buoyancy of the biodegradable buoy is less than 80%.

[0610] Experimental Example 8 - Buoyancy Maintenance Evaluation #2 <Thermal Fatigue Test>

[0611] The initial buoyancy of each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 was measured according to Experimental Example 6. Subsequently, each biodegradable buoy was immersed in warm water at 60°C for 10 hours and then in water at 25°C for 10 hours, a process repeated 15 times. The buoyancy of each biodegradable buoy was then measured and evaluated according to the following criteria. The results are shown in Table 5 below.

[0612] Eligibility: The ratio of the buoyancy after 15 immersions of the biodegradable buoy to the initial buoyancy of the biodegradable buoy is greater than 80%.

[0613] Ineligible: The ratio of the buoyancy after 15 immersions of the biodegradable buoy to the initial buoyancy of the biodegradable buoy is less than 80%.

[0614] Experimental Example 9 - Buoyancy Maintenance Evaluation #3 <Internal Pressure Test>

[0615] The initial buoyancy of each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 was measured according to Experimental Example 6. Each biodegradable buoy was then placed in a high-pressure chamber and maintained at 3 atm for 30 minutes. The buoyancy of each biodegradable buoy was then measured and evaluated according to the following criteria. The results are shown in Table 5 below.

[0616] Eligibility: The ratio of the initial buoyancy of the biodegradable buoy to the buoyancy after exposure to 3 atmospheres of pressure for 30 minutes is greater than 90%.

[0617] Ineligible: The ratio of the initial buoyancy of the biodegradable buoy to the buoyancy after exposure to 3 atmospheres of pressure for 30 minutes is less than 90%.

[0618] Experimental Example 10 - Buoyancy Retention Evaluation #4 <Injection Joint Fatigue Test>

[0619] The initial buoyancy of each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3 was measured according to Experimental Example 6. Subsequently, each biodegradable buoy was placed between two opposing load-applying plates, and a load of 3,000 N was applied and then removed 20 times. Subsequently, the buoyancy of each biodegradable buoy was measured and evaluated according to the following criteria. The results are shown in Table 5 below.

[0620] Eligibility: The ratio of the buoyancy after 20 load application cycles to the initial buoyancy of the biodegradable buoy is greater than 80%.

[0621] Ineligible: The ratio of the buoyancy after 20 load application cycles to the initial buoyancy of the biodegradable buoy is less than 80%.

[0622] Experimental Example 11 - Impact Resistance Test

[0623] As illustrated in Fig. 1, a 10 kg branch-shaped weight was prepared. For each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3, the branch-shaped weight was allowed to fall freely from a height of 150 cm. In addition, the branch-shaped weight was allowed to hit each biodegradable buoy by increasing the free fall height by 10 cm from the height of 150 cm, and the results were evaluated according to the following criteria. The results are shown in Table 5 below.

[0624] Eligibility: The above biodegradable buoy has a breaking height exceeding 200 cm.

[0625] Ineligible: The above biodegradable buoy has a breaking height of 200 cm or less.

[0626] Experimental Example 12 - Binding Ring Load Stability Test

[0627] As illustrated in Figure 3, ropes were hung on the first and second rings of each of the biodegradable buoys manufactured in Examples 1 to 8 and Comparative Examples 1 to 3. Thereafter, the breaking strength of the first and second rings when pulled in opposite directions was measured and evaluated according to the following criteria. The results are presented in Table 5 below.

[0628] Eligibility: Breaking strength exceeding 5,000 N

[0629] Unqualified: Breaking strength less than 5,000 N

[0630] Experimental Example 13 - Environmental Hazard Test

[0631] For each biodegradable buoy manufactured in Examples 1 to 8 and Comparative Examples 1 to 3, an organotin compound test according to KS K 0737, a heavy metal test according to EN 71 Part 3, and a flame retardant test according to KS C IEC 62321 and KS M 1072 were performed. For the flame retardant test, samples were collected from the inner central point of the biodegradable buoy. Evaluation was performed according to the following criteria, and the results are shown in Table 5 below.

[0632] <Organotin Compound Test>

[0633] - Eligibility: Not detected

[0634] - Ineligible: Detected

[0635] Heavy Metal Test

[0636] - Eligibility: Antimony (Sb) 560 mg / kg or less, chromium (Cr) 460 mg / kg or less, arsenic (As) 47 mg / kg or less, lead (Pb) 23 mg / kg or less, barium (Ba) 18,750 mg / kg or less, mercury (Hg) 94 mg / kg or less, cadmium (Cd) 17 mg / kg or less, and selenium (Se) 460 mg / kg or less are all met.

[0637] - Ineligible: Exceeds the above heavy metal standards by at least one

[0638] Flame retardant test

[0639] - Eligible: No PBBs, PBDEs, TBBPA, or HBCD detected

[0640] - Ineligible: At least one of PBBs, PBDEs, TBBPA, and HBCD was detected.

[0641]

[0642] Buoyancy test Marine environmental exposure test Thermal fatigue test Pressure test Injection joint volume fatigue test Impact resistance test Binding ring load stability test Environmental hazard test Organotin compound test Heavy metal test Flame retardant test Example 1 Qualified ... 8 Qualified Qualified Qualified Qualified Qualified Qualified Qualified Qualified Comparison Example 1 Qualified Qualified Qualified Not Qualified Not Qualified Not Qualified Qualified Qualified Comparison Example 2 Qualified Not Qualified Not Qualified Not Qualified Qualified Qualified Qualified Qualified Qualified Comparison Example 3 Qualified Not ...

[0643]

[0644] As can be seen in Tables 4 and 5 above, Examples 1 to 8, in which the biodegradable resin compositions met a biodegradability of 75% to 97% after 9 weeks and a hydrolysis degree of 35% to 65% after 1 week, had a biodegradability equivalent to or higher than that of Comparative Examples 1 to 3, had excellent weather resistance and mechanical properties, and were able to function properly as marine buoys even under various operating conditions depending on changes in temperature, pressure, etc.

[0645]

[0646] The present invention can be applied to a biodegradable buoy having excellent biodegradability and water resistance and a method for manufacturing the same.

Claims

1. Contains a biodegradable resin composition, The above biodegradable resin composition has a biodegradability of 75% to 97% after 9 weeks, The above biodegradable resin composition has a degree of hydrolysis of 35% to 65% after one week, The above biodegradability and hydrolysis degree are measured by the following measurement method 1: [Measurement Method 1] The biodegradability after 9 weeks is the initial number-average molecular weight decrease rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 ㎛ and a size of 30 mm X 30 mm and placed under compost conditions of a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight decrease rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

2. In paragraph 1, A biodegradable buoy having a wet hardness reduction rate of 15% or less of the above biodegradable resin composition, wherein the wet hardness reduction rate is measured by the following measuring method 2: [Measurement Method 2] The above biodegradable resin composition is processed into a biodegradable resin block having a thickness of 2.5 mm and a size of 10 mm X 10 mm, and the initial hardness of the biodegradable resin block and the wet hardness after the biodegradable resin block is immersed in water at 30° C. for 24 hours are measured, and the wet hardness reduction rate is a value obtained by dividing the difference in the wet hardness from the initial hardness by the initial hardness.

3. In paragraph 1, Biodegradable buoys having a breaking height of more than 200 cm as measured by the following measuring method 3: [Measurement Method 3] A 10 kg branch-shaped weight is prepared, the branch-shaped weight freely falls from a height of 150 cm to hit the biodegradable buoy, the branch-shaped weight increases the free fall height by 10 cm from the height of 150 cm to hit the biodegradable buoy, the breaking height is the height at which the biodegradable buoy breaks, the branch-shaped weight is a hemisphere having a lower radius of 63 mm and includes a body portion extending upwards to a length three times the lower radius, the diameter of the body portion extending upwards gradually decreases, and the diameter at the upper end is 63 mm.

4. In paragraph 1, A biodegradable buoy having a first buoyancy retention rate exceeding 80% as measured by the following measuring method 4: [Measurement Method 4] The above biodegradable buoy is immersed in seawater at a depth of 5 m at 25°C for 23 hours, and then dried for 1 hour; this process is repeated for 60 days, and the first buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 60 days to the initial buoyancy of the biodegradable buoy.

5. In paragraph 1, A biodegradable buoy having a second buoyancy retention rate of greater than 80% as measured by the following measuring method 5: [Measurement Method 5] The above biodegradable buoy is immersed in warm water at 60°C for 10 hours, and then in water at 25°C for 10 hours, and this process is repeated 15 times, and the second buoyancy maintenance rate is the ratio of the buoyancy of the biodegradable buoy after 15 immersions to the initial buoyancy of the biodegradable buoy.

6. In paragraph 1, A biodegradable buoy having a third buoyancy retention rate exceeding 90% as measured by the following measuring method 6: [Measurement Method 6] The above biodegradable buoy is placed in a hyperbaric chamber at 3 atm for 30 minutes, and the third buoyancy maintenance ratio is the ratio of the buoyancy of the biodegradable buoy after being exposed to 3 atm for 30 minutes to the initial buoyancy of the biodegradable buoy.

7. In paragraph 1, A biodegradable buoy having a fourth buoyancy retention rate of greater than 80% as measured by the following measuring method 7: [Measurement Method 7] The above biodegradable buoy is placed between two load pressure plates facing each other, and after a load of 3,000 N is applied and the process of removing the load is performed 20 times, the fourth buoyancy maintenance rate is a ratio of the buoyancy of the biodegradable buoy after the load application process is performed 20 times to the initial buoyancy of the biodegradable buoy.

8. In paragraph 1, A biodegradable buoy comprising a first ring and a second ring opposite to the first ring, wherein when the first ring and the second ring are pulled in opposite directions, the biodegradable buoy has a breaking strength exceeding 5,000 N.

9. In paragraph 1, A biodegradable buoy, wherein the biodegradable resin composition is processed into a biodegradable sheet having a thickness of 300 ㎛ and a size of 10 cm Х 10 cm, and when the biodegradable sheet is irradiated with ultraviolet rays from a UVA 340 ultraviolet lamp at an intensity of 0.75 W / ㎡, the tensile strength of the biodegradable sheet decreases by 5% to 40% from the beginning of the ultraviolet irradiation to 1 day.

10. In paragraph 1, A biodegradable buoy wherein the biodegradable resin composition comprises a polylactic acid-based resin and a polybutylene adipate terephthalate-based resin.

11. In paragraph 10, A biodegradable buoy comprising the above biodegradable resin composition comprising an inorganic filler and an additive.

12. In paragraph 1, A biodegradable buoy wherein the biodegradable resin composition has a seawater decomposition rate of 5% to 20% after 3 months, and the seawater decomposition rate is measured at a temperature of 30° C. according to ASTM D6691. 13.(a) a step of preparing a biodegradable resin composition; and (b) comprising a step of injecting the biodegradable resin composition; The above biodegradable resin composition has a biodegradability of 75% to 97% after 9 weeks, The above biodegradable resin composition has a degree of hydrolysis of 35% to 65% after one week, The above biodegradability and the above hydrolysis degree are measured by the following measurement method 1: Method for manufacturing a biodegradable buoy: [Measurement Method 1] The biodegradability after 9 weeks is the initial number-average molecular weight decrease rate of the biodegradable resin composition when the biodegradable resin composition is processed into flakes having a thickness of 300 ㎛ and a size of 30 mm X 30 mm and placed under compost conditions of a temperature of 60° C. and a humidity of 90% for 63 days, and the hydrolysis degree after 1 week is the initial number-average molecular weight decrease rate of the biodegradable resin composition when the flakes are placed under conditions of a temperature of 80° C. and a humidity of 100% for 7 days.

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