Biodegradable polyester resin composition and biodegradable molded product comprising same

Abstract

A biodegradable polyester resin composition and a biodegradable molded product comprising same, according to the present invention, comprise: a biodegradable polyester resin including a diol-derived unit, an aliphatic dicarboxylic acid-derived unit and an aromatic dicarboxylic acid-derived unit; a softener including polyether glycol; and a yellowing inhibitor.

Description

Biodegradable polyester resin composition and biodegradable molded article comprising the same

[0001] The present invention relates to a biodegradable polyester resin composition and a biodegradable molded article comprising the same.

[0002] With growing concerns about environmental issues, solutions are being sought for the disposal of various household goods, especially disposable products. Specifically, petroleum-based polymer materials are widely used in the manufacture of various products such as films, fibers, packaging materials, bottles, and containers due to their low cost and excellent processability. However, when incinerated at the end of their useful life, they emit hazardous substances, and depending on the type, they can take hundreds of years to completely decompose naturally.

[0003] To overcome the limitations of these petroleum-based polymer materials, active research is being conducted on biodegradable resins that decompose in a relatively short period of time. Biodegradable resins such as polylactic acid (PLA), polybutyleneadipate terephthalate (PBAT), and polybutylene succinate (PBS) are being introduced as alternatives.

[0004] The present invention provides a biodegradable polyester resin composition having excellent biodegradability, improved processability, and reduced yellowing, and a biodegradable molded article comprising the same.

[0005]

[0006] A biodegradable polyester resin composition according to the present invention comprises a biodegradable polyester resin comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit, a softener comprising polyether glycol, and a yellowing inhibitor.

[0007] In one embodiment of the present invention, the polyether glycol may be selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and combinations thereof.

[0008] In one embodiment of the present invention, the polyether glycol may have a number average molecular weight of 500 g / mol to 3,000 g / mol.

[0009] In one embodiment of the present invention, the softening agent content may be 1,000 ppm to 100,000 ppm based on the total weight of the biodegradable polyester resin composition.

[0010] In one embodiment of the present invention, the biodegradable polyester resin includes the softening agent-derived unit, and the content of the softening agent-derived unit may be 750 ppm to 75,000 ppm based on the total weight of the biodegradable polyester resin.

[0011] In one embodiment of the present invention, the yellowing inhibitor may include at least one of a UV blocker, an antioxidant, and a light stabilizer.

[0012] In one embodiment of the present invention, the content of the yellowing inhibitor may be 500 ppm to 50,000 ppm based on the total weight of the biodegradable polyester resin composition.

[0013] In one embodiment of the present invention, the biodegradable polyester resin composition may have an isothermal crystallization time of 10 to 22 minutes at 90°C according to the following measurement method 1.

[0014] [Measurement Method 1]

[0015] 1) The biodegradable polyester resin composition is heated to 220°C at a heating rate of 10°C / min, and then maintained for 5 minutes.

[0016] 2) Afterwards, the biodegradable polyester resin composition is cooled to 90°C at a cooling rate of 100°C / min, and then maintained in an isothermal state for 100 minutes.

[0017] 3) Using a differential scanning calorimeter, the time taken for the total area of ​​the crystallization peak of the biodegradable polyester resin composition to become half of the total area of ​​the crystallization peak of the biodegradable polyester resin composition is measured.

[0018] In one embodiment of the present invention, the biodegradable polyester resin composition may have a tensile strength reduction rate of 10% to 20% according to the following measurement method 2.

[0019] [Measurement Method 2]

[0020] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0021] 2) The first tensile strength of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM).

[0022] 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60 ℃ and 80 RH%, the second tensile strength is measured at a speed of 100 mm / min using the universal testing machine.

[0023] 4) Calculate the tensile strength reduction rate according to Equation 1 below.

[0024] [Formula 1]

[0025] Tensile strength reduction rate (%) = [{First tensile strength (MPa) - Second tensile strength (MPa)} / First tensile strength (MPa)] × 100

[0026] In one embodiment of the present invention, the biodegradable polyester resin composition may have a reduction in elongation at break of 1% to 15% according to the following measurement method 3.

[0027] [Measurement Method 3]

[0028] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0029] 2) The first breaking elongation of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM).

[0030] 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60°C and 80 RH%, the second breaking elongation is measured at a speed of 100 mm / min using the above universal testing machine.

[0031] 4) Calculate the reduction rate of elongation at break according to Equation 2 below.

[0032] [Formula 2]

[0033] Breaking elongation reduction rate (%) = [{First breaking elongation (%) - Second breaking elongation (%)} / First breaking elongation (%)] × 100

[0034] In one embodiment of the present invention, the biodegradable polyester resin composition may have an elastic recovery rate of 30% to 80% according to the following measurement method 4.

[0035] [Measurement Method 4]

[0036] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0037] 2) The above specimen is heated to 70°C using a dynamic mechanical analyzer (DMA), and then a stress of 0.8 MPa is applied for 60 minutes.

[0038] 3) After removing the stress on the above specimen, leave it for 20 minutes.

[0039] 4) Using the above DMA, the strain is measured from the time point at which the stress is removed to the time point after leaving the specimen for 20 minutes.

[0040] In one embodiment of the present invention, the biodegradable polyester resin composition may have a yellowness increase rate of 35% to 100% according to the following measurement method 5.

[0041] A biodegradable molded article according to the present invention comprises a biodegradable polyester resin composition comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit, a softener comprising a polyether glycol, and a yellowing inhibitor.

[0042] In one embodiment of the present invention, the biodegradable molded product may be a nonwoven fabric, an injection molded product, or a foam molded product.

[0043]

[0044] The biodegradable polyester resin composition according to the present invention comprises a type of biodegradable polyester resin selected and a softener including polyether glycol.

[0045] The above softening agent can function as a soft segment within the biodegradable polyester resin, thereby reducing elastic recovery, thereby improving plasticity properties and enhancing processability. In addition, water resistance can be improved, thereby minimizing changes in mechanical properties due to environmental changes.

[0046] In addition, the biodegradable polyester resin composition according to the present invention comprises a biodegradable polyester resin selected from a variety of biodegradable polyester resins, a softener comprising polyether glycol, and a yellowing inhibitor. The yellowing inhibitor can reduce yellowing that may be caused by the softener.

[0047] In addition, the biodegradable polyester resin composition according to the present invention can have a reduced crystallization time, and thus can be manufactured into a biodegradable molded product by various processes such as a spinning process, an injection process, and a foaming process.

[0048] In addition, a biodegradable molded product manufactured from the biodegradable polyester resin composition is naturally biodegradable, so it has the effect of not requiring incineration or emitting harmful substances.

[0049]

[0050] 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.

[0051] Additionally, when a component is referred to as "including" in this specification or application, unless otherwise specifically stated, this does not exclude other components, but rather implies the inclusion of additional components. 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.

[0052] Additionally, 'ppm' in this specification or application means weight basis.

[0053] Additionally, the term 'derived from' in this specification or application means a component, structure, or substance itself derived from a substance.

[0054] Hereinafter, a biodegradable polyester resin composition according to the present invention and a biodegradable molded article comprising the same will be described.

[0055]

[0056] A biodegradable polyester resin composition according to the present invention comprises a biodegradable polyester resin comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit.

[0057] 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.

[0058] 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.

[0059] The above diol may be selected from the group consisting of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol or derivatives thereof.

[0060] The above diol may include 1,4-butanediol or a derivative thereof.

[0061] 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.

[0062] The above aliphatic dicarboxylic acid may be selected from the group consisting of adipic acid, succinic acid, sebacic acid or derivatives thereof.

[0063] The above aliphatic dicarboxylic acid may include adipic acid or a derivative thereof.

[0064] 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.

[0065] 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.

[0066] The above aromatic dicarboxylic acid may include terephthalic acid, dimethyl terephthalate or derivatives thereof.

[0067] In the biodegradable polyester resin, the molar ratio of the total diol residues including the diol and 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, or from about 1:0.95 to about 1:1.05.

[0068] In the biodegradable polyester resin, the molar ratio of the aromatic dicarboxylic acid residue and the aliphatic dicarboxylic acid residue may be from about 3:7 to about 7:3, from about 3.3:6.7 to about 6.7:3.3, from about 4:6 to about 6:4, or from about 4.2:5.8 to about 5:5.

[0069] The biodegradable polyester resin may include a diol residue derived from 1,4-butanediol in an amount of about 90 mol% or more, about 95 mol% or more, or about 98 mol% or more based on the total diol.

[0070] The biodegradable polyester resin may include an aromatic dicarboxylic acid residue derived from terephthalic acid or dimethyl terephthalate in an amount of about 30 mol% to about 70 mol%, about 35 mol% to about 65 mol%, about 40 mol% to about 60 mol%, or about 43 mol% to about 53 mol% based on the total dicarboxylic acid.

[0071] The biodegradable polyester resin may include an aliphatic dicarboxylic acid residue derived from adipic acid in an amount of about 30 mol% to about 70 mol%, about 35 mol% to about 65 mol%, about 40 mol% to about 60 mol%, or about 47 mol% to about 57 mol% based on the total dicarboxylic acid.

[0072] The biodegradable polyester resin may include a first block and a second block. The biodegradable polyester resin may have a molecular structure in which the first block and the second block are alternately bonded.

[0073] 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. The first block may refer to the sum of repeating units of the diol and the aromatic dicarboxylic acid before the aliphatic dicarboxylic acid is bonded.

[0074] 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. The second block may refer to the sum of repeating units of the diol and the aliphatic dicarboxylic acid before the aromatic dicarboxylic acid is bonded.

[0075] In the biodegradable polyester resin, the ratio (X / Y) of the number (X) of the first blocks and the number (Y) of the second blocks may be about 0.5 to about 1.5, about 0.6 to about 1.4, about 0.7 to about 1.3, about 0.75 to about 1.2, or about 0.8 to about 1. The number of the first blocks may be smaller than the number of the second blocks.

[0076] The number of said first blocks may be about 30 to about 300, about 40 to about 250, about 50 to about 220, about 60 to about 200, about 70 to about 200, or about 75 to about 200.

[0077] The number of the first blocks may vary depending on the content of the aromatic dicarboxylic acid, the number average molecular weight of the biodegradable polyester resin, and the degree of alternation described below.

[0078] The number of said second blocks may be about 30 to about 300, about 40 to about 250, about 50 to about 220, about 60 to about 200, about 70 to about 200, or about 75 to about 200.

[0079] The number of the second blocks may vary depending on the content of the aliphatic dicarboxylic acid, the molecular weight of the biodegradable polyester resin, and the degree of alternation described below.

[0080] When the biodegradable polyester resin includes the first block and the second block in the above range, a biodegradable polyester resin composition including the biodegradable polyester resin can have appropriate biodegradability and improved mechanical properties.

[0081] The above biodegradable polyester resin may include the following bonding structures 1 to 3.

[0082] [Combination Structure 1]

[0083] - Aromatic dicarboxylic acids - Diols - Aliphatic dicarboxylic acids -

[0084] [Combination Structure 2]

[0085] - Aromatic dicarboxylic acid - Diol - Aromatic dicarboxylic acid -

[0086] [Combination Structure 3]

[0087] - Aliphatic dicarboxylic acid - Diol - Aliphatic dicarboxylic acid -

[0088] 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.

[0089] 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.

[0090] 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.

[0091] The above biodegradable polyester resin may have an alternating ratio.

[0092] 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.

[0093] The above-mentioned exchange ratio may be the ratio of diols bonded between heterodicarboxylic acids among the total diols.

[0094] The above exchange ratio can be calculated using the following formula 1.

[0095] [Formula 1]

[0096]

[0097] 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.

[0098] In the biodegradable polyester resin, the alternation ratio may be about 0.3 to about 0.7, about 0.37 to about 0.59, about 0.4 to about 0.56, or about 0.45 to about 0.53.

[0099] The biodegradable polyester resin may include a hard segment ratio. The hard segment ratio is the ratio of the diol bonded between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid among the diols.

[0100] 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.

[0101] The above hard segment ratio can be expressed by the following equation 2.

[0102] [Formula 2]

[0103]

[0104] 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.

[0105] The hard segment ratio may be from about 0.15 to about 0.35, from about 0.2 to about 0.3, from about 0.21 to about 0.29, or from about 0.22 to about 0.28.

[0106] The above biodegradable polyester resin composition may include a soft segment.

[0107] 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.

[0108] 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.

[0109] The above soft segment ratio can be expressed by the following equation 3.

[0110] [Formula 3]

[0111]

[0112] 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.

[0113] The soft segment ratio may be from about 0.16 to about 0.36, from about 0.21 to about 0.31, from about 0.22 to about 0.30, or from about 0.23 to about 0.29.

[0114] The above soft segment ratio may be greater than the above hard segment ratio.

[0115] 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.

[0116] The above-mentioned alternation ratio, the hard segment ratio, and the soft segment ratio can be measured by nuclear magnetic resonance spectroscopy. The biodegradable polyester resin composition is dissolved in a solvent such as CDCl3, and at room temperature, by a nuclear magnetic resonance (NMR) device, 1 H-NMR and / or 13 It can be analyzed by C-NMR analysis.

[0117] When the diol is 1,4-butanediol, the aromatic dicarboxylic acid is terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid is adipic acid, the analysis of the biodegradable polyester resin by 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.

[0118] 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 biodegradable polyester 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.

[0119] 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.

[0120] -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.

[0121] Analysis of the biodegradable polyester 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] The above exchange ratio can be derived from the following equation 4 or equation 5.

[0128] [Formula 4]

[0129]

[0130] In the above formula 4, the PA1 is the area of ​​the first peak, the PA2 is the area of ​​the second peak, the PA3 is the area of ​​the third peak, and the PA4 is the area of ​​the fourth peak.

[0131] [Formula 5]

[0132]

[0133] In the above formula 5, 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.

[0134] The above hard segment ratio can be derived from the following equation 6 or equation 7.

[0135] [Formula 6]

[0136]

[0137] In the above formula 6, the PA1 is the area of ​​the first peak, the PA2 is the area of ​​the second peak, the PA3 is the area of ​​the third peak, and the PA4 is the area of ​​the fourth peak.

[0138] [Formula 7]

[0139]

[0140] In the above formula 7, 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.

[0141] The above soft segment ratio can be derived using Equation 8 or Equation 9 below.

[0142] [Formula 8]

[0143]

[0144] In the above formula 8, the PA1 is the area of ​​the first peak, the PA2 is the area of ​​the second peak, the PA3 is the area of ​​the third peak, and the PA4 is the area of ​​the fourth peak.

[0145] [Formula 9]

[0146]

[0147] In the above formula 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.

[0148] The area of ​​the first peak may be from about 0.35 to about 0.6, from about 0.4 to about 0.55, from about 0.43 to about 0.5, from about 0.43 to about 0.52, or from about 0.45 to about 0.49.

[0149] The area of ​​the second peak may be from about 0.37 to about 0.57, from about 0.41 to about 0.54, from about 0.45 to about 0.53, from about 0.45 to about 0.55, or from about 0.47 to about 0.53.

[0150] The area of ​​the third peak may be from about 0.37 to about 0.57, from about 0.41 to about 0.54, from about 0.45 to about 0.53, from about 0.45 to about 0.55, or from about 0.47 to about 0.53.

[0151] The area of ​​the fourth peak may be from about 0.4 to about 0.7, from about 0.45 to about 0.65, from about 0.48 to about 0.6, from about 0.48 to about 0.60, or from about 0.50 to about 0.58.

[0152] The area of ​​the fifth peak may be about 0.35 to about 0.6, about 0.4 to about 0.55, about 0.43 to about 0.53, about 0.43 to about 0.52, or about 0.45 to about 0.49.

[0153] The area of ​​the sixth peak may be from about 0.35 to about 0.6, from about 0.4 to about 0.55, from about 0.43 to about 0.5, from about 0.45 to about 0.55, or from about 0.47 to about 0.53.

[0154] The area of ​​the seventh peak may be from about 0.41 to about 0.71, from about 0.45 to about 0.65, from about 0.48 to about 0.6, from about 0.45 to about 0.55, or from about 0.47 to about 0.53.

[0155] The area of ​​the eighth peak may be from about 0.4 to about 0.7, from about 0.45 to about 0.65, from about 0.48 to about 0.6, or from about 0.50 to about 0.58.

[0156] The area of ​​the above tenth peak may be from about 0.7 to about 2.5, from about 0.75 to about 2, from about 0.8 to about 1.5, from about 1.0 to about 1.15, or from about 1.02 to about 1.13.

[0157] The area of ​​the eleventh peak may be from about 0.7 to about 3.5, from about 0.7 to about 3, from about 0.8 to about 2.5, from about 1.0 to about 1.15, or from about 1.02 to about 1.13.

[0158] The sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may be from about 1.49 to about 2.44, from about 1.81 to about 2.16, from about 1.9 to about 2.2, or from about 1.95 to about 2.1. Here, the sum of the area of ​​the first peak, the area of ​​the second peak, the area of ​​the third peak, and the area of ​​the fourth peak may mean the sum of the total number of ester bonds based on the number of terephthalic acids.

[0159] 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, or 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 biodegradable polyester resin.

[0160] 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, about 0.67 to about 2, about 0.96 to about 1.40, or 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 biodegradable polyester resin. That is, the higher the ratio of the area of ​​the fourth peak to the area of ​​the first peak, the more the biodegradable polyester resin may have improved adhesive properties.

[0161] 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, from about 0.91 to about 1.33, from about 1.0 to about 1.2, or from about 1.01 to about 1.1.

[0162] 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, about 0.81 to about 1.11, about 0.85 to about 0.95, or about 0.86 to about 0.94.

[0163] 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, from about 0.96 to about 1.40, from about 0.8 to about 1.2, or from about 0.9 to about 1.1.

[0164] The ratio of the area of ​​the sixth peak to the area of ​​the second peak (area of ​​the sixth peak / area of ​​the second peak) may be from about 0.58 to about 1.71, from about 0.86 to about 1.16, from about 0.8 to about 1.2, or from about 0.9 to about 1.1.

[0165] 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 about 0.72 to about 1.92, about 0.91 to about 1.33, about 0.8 to about 1.2, or about 0.9 to about 1.1.

[0166] 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, about 0.80 to about 1.2, or about 0.9 to about 1.1.

[0167] The number average molecular weight of the biodegradable polyester resin may be 20,000 g / mol to 100,000 g / mol, 20,000 g / mol to 80,000 g / mol, 20,000 g / mol to 70,000 g / mol, or 30,000 g / mol to 62,000 g / mol. When the above range is satisfied, the resin may have excellent adhesion to fertilizer and a degree of crystallinity that can improve the coating processability. The number average molecular weight may be measured using gel permeation chromatography (GPC).

[0168] The biodegradable polyester resin composition according to the present invention comprises a softener comprising polyether glycol.

[0169] Conventional biodegradable polyester resins comprising diol-derived units, aliphatic dicarboxylic acid-derived units, and aromatic dicarboxylic acid-derived units have the problem of being vulnerable to moisture and easily deteriorating in mechanical properties due to the inclusion of a large number of ester groups. In addition, the biodegradable polyester resins have high elasticity, which results in reduced plasticity characteristics and poor processability, making it difficult to expand their applications for manufacturing various products through spinning processes, injection processes, and foaming processes.

[0170] To solve the above problems, the inventors of the present invention introduced a softening agent including polyether glycol that can act as a soft segment in the biodegradable polyester resin.

[0171] By introducing the above softening agent, the ratio of the soft segment, which is the ratio of the aliphatic dicarboxylic acid and the diol bonded between the aliphatic dicarboxylic acid, of the biodegradable polyester resin composition increases, so that water resistance can be improved and changes in mechanical properties due to environmental changes can be minimized.

[0172] Furthermore, by selecting a softening agent including the polyether glycol, the elastic recovery rate of the biodegradable polyester resin can be reduced, and its plasticity characteristics can be improved, thereby enhancing processability. This enables expanded applications for manufacturing various products through processes such as spinning, injection, and foaming.

[0173] The content of the softening agent may be 1,000 ppm to 100,000 ppm, 1,000 ppm to 50,000 ppm, 1,000 ppm to 30,000 ppm, or 1,000 ppm to 15,000 ppm based on the total weight of the biodegradable polyester resin composition. When the above range is satisfied, the migration phenomenon that may occur on the surface of the biodegradable molded product can be suppressed, and the purpose of the present invention, maintenance of mechanical properties and improvement of processability, can be achieved.

[0174] The softening agent may be compounded by mixing with the biodegradable polyester resin. The softening agent may be produced by being added during the manufacturing process of the biodegradable polyester resin, for example, during the esterification reaction, the condensation polymerization reaction, or both of the above reactions. Preferably, the softening agent may be added during the manufacturing process of the biodegradable polyester resin. As a result, the softening agent may be copolymerized with a polymer including the diol-derived unit, the aliphatic dicarboxylic acid-derived unit, and the aromatic dicarboxylic acid-derived unit, thereby functioning as a soft segment in the biodegradable polyester resin.

[0175] The biodegradable polyester resin may include the softening agent-derived unit, and the content of the softening agent-derived unit may be 750 ppm to 75,000 ppm, 750 ppm to 50,000 ppm, 750 ppm to 30,000 ppm, 750 ppm to 20,000 ppm, or 1,000 ppm to 10,000 ppm based on the total weight of the biodegradable polyester resin. When the above range is satisfied, the purpose of the present invention, maintenance of mechanical properties and improvement of processability, can be achieved, and yellowing phenomenon can be minimized.

[0176] The above polyether glycol may be selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and combinations thereof.

[0177] The polyether glycol may have a number average molecular weight of 500 g / mol to 3,000 g / mol, 500 g / mol to 2,000 g / mol, 500 g / mol to 1,500 g / mol, or 700 g / mol to 1,500 g / mol. When the above range is satisfied, the mechanical properties that are the purpose of the present invention can be maintained, and the phenomenon of the copolymerization reaction being limited due to steric hindrance during the polymerization process of the biodegradable polyester resin can be suppressed.

[0178] The biodegradable polyester resin composition according to the present invention comprises a yellowing inhibitor.

[0179] As described above, the biodegradable polyester resin composition according to the present invention incorporates a softening agent including polyether glycol to improve mechanical properties and processability. However, a chromophore may be formed by the carbonyl group derived from the polyether glycol, and this chromophore may react with external environments such as oxygen and / or light, resulting in yellowing. Consequently, even though the mechanical properties and processability of the biodegradable polyester resin composition are improved, its appearance limits its application to a wider range of applications.

[0180] The biodegradable polyester resin composition can reduce yellowing that may be caused by the softening agent by including the yellowing inhibitor.

[0181] The content of the above-mentioned yellowing inhibitor may be 500 ppm to 50,000 ppm, 500 ppm to 40,000 ppm, 500 ppm to 30,000 ppm, or 500 ppm to 10,000 ppm based on the total weight of the biodegradable polyester resin composition. When the above range is satisfied, the yellowing phenomenon can be suppressed without lowering the biodegradability.

[0182] The above yellowing inhibitor may include at least one of a UV blocker, an antioxidant, and a light stabilizer.

[0183] The UV blocker can absorb ultraviolet rays, thereby inhibiting photooxidation caused by ultraviolet rays. The weight average molecular weight (Mw) of the UV blocker may be 100 g / mol to 10,000 g / mol, 100 g / mol to 5,000 g / mol, 100 g / mol to 3,000 g / mol, 100 g / mol to 1,000 g / mol, 100 g / mol to 800 g / mol, or 200 g / mol to 800 g / mol. The melting point of the UV blocker may be 50°C or higher, 80°C or higher, 100°C or higher, 150°C or higher, or 150°C or higher to 230°C or lower. When the above range is satisfied, yellowing due to the influence of ultraviolet rays can be inhibited without reducing biodegradability.

[0184] The above UV blocking agent may include at least one selected from the group consisting of benzotriazole derivatives, hydroxybenzophenone, hydroxyphenyltrizine, and esters of substituted or unsubstituted benzoic acid.

[0185] The content of the UV blocking agent may be 500 ppm to 10,000 ppm, 500 ppm to 5,000 ppm, 500 ppm to 3,000 ppm, or 1,000 ppm to 3,000 ppm based on the total weight of the biodegradable polyester resin composition.

[0186] The above antioxidant may include at least one selected from the group consisting of a phosphorus-based antioxidant, a phenol-based antioxidant, and a pentaerythritol-based antioxidant.

[0187] The above-mentioned phosphorus antioxidant may be at least one selected from the group consisting of triesters, diesters, monoesters of phosphorous acid, such as triphenyl phosphite, trisnonylphenyl phosphite, and tris(2,4-di-t-butylphenyl)phosphite, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl)phosphate, and 2-ethylphenyl diphenyl phosphate.

[0188] The above phenolic antioxidants are α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-t-butyl-4-(N,N-dimethylaminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzyl phosphonate diethyl ester, 2,2-bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl It may be at least one selected from the group consisting of bis(3-(3,5-di-tert)-butyl-4-hydroxyphenyl)propanoate), pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane.

[0189] The above antioxidant may further include at least one selected from the group consisting of BHT, ascorbic acid, catechin, quercetin, dodecyl gallate, TBHQ, Ralox, Irganox 1135, Irganox 1076, nordihydroguaiaretic acid, epicatechin gallate, epigallocatechin gallate, epigallocatein, propyl gallate, 2,3,5-trihydroxybutyrophenone, butylated hydroxyanisole, 4-hydroxymethyl-2,6-di-tert-butylphenol, α-tocopherol, resveratrol, rutin, astaxanthin, lycopene, beta-carotene, and melatonin.

[0190] The content of the UV blocking agent may be 500 ppm to 10,000 ppm, 500 ppm to 5,000 ppm, 500 ppm to 3,000 ppm, or 1,000 ppm to 3,000 ppm based on the total weight of the biodegradable polyester resin composition.

[0191] The above-described light stabilizer can suppress the degradation reaction of the biodegradable polyester resin by capturing free radicals generated by ultraviolet rays. In addition, the light stabilizer can suppress the oxidation reaction that occurs when the biodegradable polyester resin is exposed to ultraviolet rays. In addition, the light stabilizer absorbs ultraviolet rays, and the absorbed energy is released as heat, thereby reducing the amount of ultraviolet rays reaching the biodegradable polyester resin.

[0192] The above light stabilizer may include at least one of HALS (hindered amine light stabilizer), benzotriazole, and benzophenol compounds.

[0193] The content of the UV blocking agent may be 800 ppm to 10,000 ppm, 800 ppm to 5,000 ppm, 800 ppm to 3,000 ppm, or 800 ppm to 2,000 ppm based on the total weight of the biodegradable polyester resin composition.

[0194] Preferably, the yellowing inhibitor may include a UV blocker and an antioxidant. The weight ratio of the UV blocker and the antioxidant may be 1:10 to 10:1, 1:8 to 8:1, 1:6 to 6:1, 1:4 to 4:1, 1:2 to 2:1, or 1:1.5 to 1.5:1. When the above range is satisfied, ultraviolet rays of various wavelength ranges can be blocked, so that the yellowing phenomenon can be suppressed more effectively. In addition, the initial damage to the biodegradable polyester resin can be suppressed by absorbing ultraviolet rays by the UV blocker, and the secondary damage to the biodegradable polyester resin can be suppressed by neutralizing the remaining free radicals by the antioxidant, so that the yellowing phenomenon can be suppressed more effectively.

[0195] The biodegradable polyester resin composition may have an isothermal crystallization time at 90°C of 10 to 22 minutes, 11 to 22 minutes, 12 to 22 minutes, or 13 to 22 minutes according to the following measurement method 1.

[0196] [Measurement Method 1]

[0197] 1) The biodegradable polyester resin composition is heated to 220°C at a heating rate of 10°C / min, and then maintained for 5 minutes.

[0198] 2) Afterwards, the biodegradable polyester resin composition is cooled to 90°C at a cooling rate of 100°C / min, and then maintained in an isothermal state for 100 minutes.

[0199] 3) Using a differential scanning calorimeter, the time taken for the total area of ​​the crystallization peak of the biodegradable polyester resin composition to become half of the total area of ​​the crystallization peak of the biodegradable polyester resin composition is measured.

[0200] The above isothermal crystallization time is to rapidly cool the biodegradable polyester resin composition in a molten state and evaluate the time until crystallization.

[0201] A short isothermal crystallization time indicates rapid crystallization. Rapid crystallization may imply that molecular motion is suppressed and crystals are formed in the early stages after cooling.

[0202] The fact that the biodegradable polyester resin composition has an isothermal crystallization time according to the measurement method 1 may mean that the biodegradable polyester resin composition has suitable properties that enable it to be manufactured into a molded product in various processes such as a spinning process, an injection process, and a foaming process.

[0203] The biodegradable polyester resin composition may have a tensile strength reduction rate of 10% to 20%, 11% to 20%, 12% to 20%, or 12% to 18% according to the following measurement method 2.

[0204] [Measurement Method 2]

[0205] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0206] 2) The first tensile strength of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM).

[0207] 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60 ℃ and 80 RH%, the second tensile strength is measured at a speed of 100 mm / min using the universal testing machine.

[0208] 4) Calculate the tensile strength reduction rate according to Equation 1 below.

[0209] [Formula 1]

[0210] Tensile strength reduction rate (%) = [{First tensile strength (MPa) - Second tensile strength (MPa)} / First tensile strength (MPa)] Х 100

[0211] The biodegradable polyester resin composition may have a reduction in elongation at break of 1% to 15%, 2% to 15%, 2% to 12%, or 2% to 10% according to the following measurement method 3.

[0212] [Measurement Method 3]

[0213] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0214] 2) The first breaking elongation of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM).

[0215] 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60°C and 80 RH%, the second breaking elongation is measured at a speed of 100 mm / min using the above universal testing machine.

[0216] 4) Calculate the reduction rate of elongation at break according to Equation 2 below.

[0217] [Formula 2]

[0218] Breaking elongation reduction rate (%) = [{First breaking elongation (%) - Second breaking elongation (%)} / First breaking elongation (%)] × 100

[0219] The lower the tensile sensitivity reduction rate and elongation at break reduction rate, the better the mechanical properties are maintained over time.

[0220] The fact that the biodegradable polyester resin composition has a tensile strength reduction rate and an elongation at break reduction rate according to the above measurement methods 2 and 3 may mean that the biodegradable polyester resin composition has a feature in which changes in mechanical properties due to environmental changes are minimized due to improved water resistance.

[0221] The above biodegradable polyester resin composition may have an elastic recovery rate of 30% to 80%, 40% to 80%, 50% to 80%, or 60% to 80% according to the following measurement method 4.

[0222] [Measurement Method 4]

[0223] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0224] 2) The above specimen is heated to 70°C using a dynamic mechanical analyzer (DMA), and then a stress of 0.8 MPa is applied for 60 minutes.

[0225] 3) After removing the stress on the above specimen, leave it for 20 minutes.

[0226] 4) Using the above DMA, the strain is measured from the time point at which the stress is removed to the time point after leaving the specimen for 20 minutes.

[0227] The above elastic recovery rate represents the elastic properties of the biodegradable polyester resin composition.

[0228] The fact that the above biodegradable polyester resin composition has an elastic recovery rate according to the above measurement method 4 may mean that the elastic recovery rate is reduced compared to a conventional biodegradable polyester resin composition, thereby improving plasticity characteristics and processability.

[0229] The biodegradable polyester resin composition may have a yellowness increase rate of 35% to 100%, 35% to 80%, 35% to 50%, or 35% to 40% according to the following measurement method 5.

[0230] [Measurement Method 5]

[0231] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B.

[0232] 2) For the above specimen, the first yellowness is measured according to ASTM E313-2005.

[0233] 3) Put the above specimen into the QUV tester and apply 0.5 W / m 2 After irradiating with UV for 7 days under high light, the second yellowness is measured according to ASTM E313-2005.

[0234] 4) Calculate the yellowness increase rate according to Equation 3 below.

[0235] [Formula 3]

[0236] Yellowness increase rate (%) = [{1st yellowness - 2nd yellowness} / 1st yellowness] × 100

[0237] The above yellowness increase rate represents the appearance characteristics of the biodegradable polyester resin composition according to changes over time.

[0238] The fact that the biodegradable polyester resin composition has a yellowness increase rate according to the above measurement method 5 may mean that the yellowing phenomenon that may be caused by the softening agent is suppressed, thereby improving the appearance characteristics.

[0239] A biodegradable molded article according to the present invention comprises a biodegradable polyester resin composition comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit, a softener comprising a polyether glycol, and a yellowing inhibitor.

[0240] The above biodegradable polyester resin composition may be the same as the biodegradable polyester resin composition described above.

[0241] The above biodegradable molded product may be a non-woven fabric, an injection molded product, or a foam molded product.

[0242] The above nonwoven fabric may include a step of producing a biodegradable yarn by a spinning process using the biodegradable polyester resin composition, a step of cooling the biodegradable yarn, a step of drawing the biodegradable yarn, and a step of forming a biodegradable yarn web by combining the cooled biodegradable yarn.

[0243] The above spinning process may include a process in which the biodegradable polyester resin composition is melted and injected into a spinning block. In the spinning block, the biodegradable polyester resin composition melted from an extruder can be spun from a nozzle. Filaments of the biodegradable polyester resin composition can be formed by the spinning block. The filaments can be solidified and crystallized by cooling to produce an undrawn biodegradable yarn.

[0244] The above step may include a step of cooling the biodegradable yarn.

[0245] The above biodegradable yarn may be an unstretched biodegradable yarn manufactured from the above biodegradable polyester resin composition.

[0246] The cooling may be performed at about 1° C. to 15° C., 1° C. to 13° C., 2° C. to 13° C., or 5° C. to 13° C. The cooling may be performed in a quenching chamber. The length of the quenching chamber may be about 1 m to 5 m, about 1 m to 4 m, about 1 m to 3 m, or about 1 m to 2 m.

[0247] When the above range is satisfied, the phenomenon of adjacent non-stretched biodegradable yarns fusing with each other can be suppressed.

[0248] The above step may include a step of stretching the cooled biodegradable yarn.

[0249] By the above stretching process, a biodegradable yarn stretched 1.1 to 3 times, 1.2 to 3 times, 1.2 to 2.7 times, 1.2 to 2.6 times, or 1.2 to 2.5 times compared to an unstretched biodegradable yarn can be produced.

[0250] The above-mentioned elongated biodegradable yarn can be heat treated at an appropriate temperature.

[0251] The above-described elongated biodegradable yarn can be wound. The above-described elongated biodegradable yarn can be wound by a winder. The winding speed of the winder can be 300 m / min to 3,000 m / min, 300 m / min to 2,500 m / min, 400 m / min to 2,500 m / min, 500 m / min to 2,500 m / min, or 250 m / min to 2,000 m / min. When the above range is satisfied, the phenomenon of the biodegradable yarns being fused or cut off from each other can be suppressed.

[0252] The biodegradable yarn may have a tensile strength of 0.5 g / de to 5.0 g / de, 0.5 g / de to 5.0 g / de, 0.5 g / de to 5.0 g / de, 0.5 g / de to 5.0 g / de, or 1.0 g / de to 3.0 g / de. The biodegradable yarn may have an elongation of 20% to 400%, 20% to 300%, 25% to 300%, 25% to 250%, 30% to 250%, or 35% to 200%. The biodegradable yarn may have a tensile strength of 1.0 g / de to 3.0 g / de and an elongation of 35% to 200%. When the above range is satisfied, the biodegradable yarns can be easily pressed together and easily applied to a biodegradable nonwoven fabric, and the mechanical strength of the biodegradable nonwoven fabric can be improved.

[0253] The above step may include a step of combining the cooled biodegradable yarns to form a biodegradable yarn web.

[0254] The method of combining the above biodegradable yarns may be by carding, air laid, water suspension, or spun bond process.

[0255] By the above process, the bonding force between the biodegradable yarn webs can be strengthened, the tensile strength and elongation can be improved, and the generation of fluff in the biodegradable nonwoven fabric can be prevented.

[0256] The above biodegradable nonwoven fabric is lightweight, has excellent strength, and has a high surface area and porosity, so it can be applied to products requiring hygroscopicity.

[0257] The biodegradable nonwoven fabric may include yarns having an average diameter of 1 μm to 500 μm, 1 μm to 400 μm, 1 μm to 300 μm, 1 μm to 200 μm, or 10 μm to 100 μm.

[0258] The biodegradable nonwoven fabric may be processed. The biodegradable nonwoven fabric may be treated with an antistatic agent to prevent static electricity. The biodegradable nonwoven fabric may be treated with a water-repellent agent to prevent water leakage. The biodegradable nonwoven fabric may be treated with an antibacterial agent to prevent water leakage.

[0259] The biodegradable nonwoven fabric may be embossed. The biodegradable nonwoven fabric may be printed. The biodegradable nonwoven fabric may be embossed or printed in a thickness and size suitable for the product to which it is applied.

[0260] The above biodegradable polyester resin composition can be manufactured into an injection molded product by an injection molding process.

[0261] The above biodegradable polyester resin composition may be a pelletized biodegradable polyester resin composition.

[0262] The pelletized biodegradable polyester resin composition can be manufactured into an injection molded product using an injection molding machine at an injection barrel temperature of 150°C to 250°C, 160°C to 250°C, 160°C to 240°C, or 160°C to 230°C.

[0263] The above injection process may be performed by injection molding methods such as injection compression molding, injection press molding, gas-assisted injection molding, foam molding, insert molding, in-mold coating molding, insulating mold molding, rapid heating and cooling mold molding, two-color molding, sandwich molding, and ultra-high-speed injection molding.

[0264] The above biodegradable polyester resin composition has excellent injection properties, has excellent releasability in the injection process, and can maintain the shape of the injection product.

[0265] The above biodegradable polyester resin composition can be manufactured into a foamed molded product by a foaming process.

[0266] The above biodegradable polyester resin composition may include a foaming agent.

[0267] The above-mentioned foaming agent may be mixed into the molten biodegradable polyester resin composition or injected under pressure, and may be a substance that changes phase from solid to gas, liquid to gas, or gas itself, and may be used to control the foaming ratio (foaming density) of the foam sheet.

[0268] The above-mentioned foaming agent may include at least one selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, inorganic gases, and water.

[0269] The above biodegradable polyester resin composition has excellent foaming properties, so that the foaming ratio can be increased when manufacturing a molded product, and a uniform foam cell size and molded product thickness can be achieved.

[0270] 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.

[0271]

[0272] Example - Preparation of biodegradable polyester resin composition

[0273] Example 1

[0274] - Step 1: Slurry preparation

[0275] 1,4-butanediol (1,4-BDO) and terephthalic acid (TPA) were mixed in a molar ratio of 1.4:1 and placed in a slurry tank (the bottom of the slurry tank was anchor type, 30 mm high to the agitator, and equipped with three rotating blades) in a non-catalytic state. At this time, the D of the terephthalic acid (TPA) 50 was 130 μm.

[0276] Thereafter, the mixture was stirred at 40°C and 100 rpm for 1 hour to prepare a slurry without phase separation.

[0277] - Step 2: Prepolymer production

[0278] The slurry prepared in the first step was fed into the reactor through a supply line.

[0279] Afterwards, 300 ppm of tetrabutyl titanate (Dupont, Tyzor TnBT product), a titanium catalyst, was added, and the first esterification reaction was performed at 220 ℃ and atmospheric pressure for approximately 1 hour and 30 minutes until 95% of the byproduct water was discharged.

[0280] Thereafter, 5,000 ppm of a softening agent (polytetramethylene ether glycol (PTMEG), number average molecular weight 1,000 g / mol)) based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid was added to the above reaction product to prepare an oligomer.

[0281] Afterwards, 50 mol% of 1,4-butanediol (1,4-BDO) based on the total mole number of diol components, 50 mol% of adipic acid (AA) based on the total mole number of dicarboxylic acid components, and 200 ppm of tetrabutyl titanate (Dupont, Tyzor TnBT product), a titanium catalyst, based on the total weight of diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid, and 100 ppm of triethyl phosphate as a stabilizer were added to the oligomer, and then a secondary 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, thereby producing a prepolymer having a number average molecular weight of 1,500 g / mol.

[0282] - Step 3: Preparation of biodegradable polyester resin composition

[0283] In the second step, 100 ppm of triethyl phosphate stabilizer was additionally added to the prepolymer prepared based on the total weight of diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid, and the mixture was stabilized for about 10 minutes.

[0284] Afterwards, the reaction mixture was heated 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 approximately 42,000 g / mol.

[0285] Afterwards, based on the polymer, 1,000 ppm of yellowing inhibitor #1 2-(2`-hydroxy-5`-methylphenyl)benzotriazole and 1,000 ppm of yellowing inhibitor #2 Irganox 1010 were added.

[0286] Thereafter, the polymer was subjected to a terminal extension reaction at a temperature of about 240°C for about 10 minutes. Thereafter, the polymer was cooled under a temperature condition of 5°C and then cut using a pellet cutter to produce biodegradable polyester resin pellets.

[0287] - Manufacturing of specimens

[0288] After preparing two Teflon sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was placed on one of the Teflon sheets.

[0289] Afterwards, about 7 g of the biodegradable polyester resin pellets manufactured above were placed in a stainless steel (SUS) frame (area of ​​12 cm × 12 cm), covered with another Teflon sheet, and placed in the center of a hot press (Manufacturer: With Lab, Model: WL 1600SA) having a surface size of about 25 cm × 25 cm.

[0290] Afterwards, it was maintained at about 210°C under a pressure of about 10 Mpa for about 3 minutes, then detached, and immediately cooled in water at about 20°C for about 30 seconds to produce a specimen with an area of ​​about 10 cm × 10 cm and a thickness of about 300 μm.

[0291]

[0292] Examples 2 to 3 and Comparative Examples 1 to 3

[0293] A biodegradable polyester resin composition and specimen were manufactured by the same process as Example 1, except that the composition and contents are shown in Table 1 below.

[0294]

[0295] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Resin type PBATP BATP BATP BATP BATP Raw material composition ratio 1,4-BDO 140 mol% 140 mol% 140 mol% 140 mol% 140 mol% 140 mol% 140 mol% TPA 47 mol% 47 mol% 47 mol% 47 mol% 47 mol% 47 mol% AA 53 mol% 53 mol% 53 mol% 53 mol% 53 mol% Softener 1) (PTMEG)5,000 ppm8,000 ppm12,000 ppm12,000 ppm--Yellowing inhibitor#12-(2`-hydroxy-5`-methylphenyl)Benzotriazole1,000 ppm1,000 ppm1,000 ppm--1,000 ppmYellowing inhibitor#2Irganox 10101,000 ppm1,000 ppm1,000 ppm--1,000 ppmResin polymer composition ratioTPA48.9 mol%48.6 mol%48.0 mol%48.0 mol%49.3 mol%49.3 mol%AA51.1 mol%51.4 mol%51.0 mo%51.0 mo%50.7 mol%50.7 mol%Softener 2)(PTMEG)3,750 ppm6,000 ppm9,000 ppm9,000 ppm--1) Content of softener (ppm): Based on the total weight of biodegradable polyester resin composition2) Content of softener (ppm): Based on the total weight of biodegradable polyester resin

[0296]

[0297] Experimental example

[0298] Experimental Example 1 - Crystallization Time

[0299] Each of the biodegradable polyester resin compositions of Examples 1 to 3 and Comparative Examples 1 to 3 was heated to 220°C at a heating rate of 10°C / min and maintained for 5 minutes. Thereafter, the temperature was lowered to 90°C at a cooling rate of 100°C / min and maintained in an isothermal state for 100 minutes.

[0300] Thereafter, using differential scanning calorimetry, the time for the total area of ​​the crystallization peak of the biodegradable polyester resin composition to become half of the total area of ​​the crystallization peak of the biodegradable polyester resin composition was measured, and the results are shown in Table 2 below.

[0301]

[0302] Experimental Example 2 - Tensile strength reduction rate after exposure to moisture environment

[0303] For each of the specimens manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, the first tensile strength (kgf / mm2 = 9.8 MPa) at a speed of 100 mm / min according to ASTM D638 was measured using a universal testing machine (UTM, model number 4206-001) manufactured by INSTRON.

[0304] Afterwards, the second tensile strength (kgf / mm2=9.8 MPa) was measured at a speed of 100 mm / min using the universal testing machine after 8 days of accelerated time change under the conditions of 60 ℃ and 80 RH%.

[0305] The tensile strength reduction rate was calculated according to Equation 1 below, and the results are shown in Table 2 below.

[0306] [Formula 1]

[0307] Tensile strength reduction rate (%) = [{First tensile strength (MPa) - Second tensile strength (MPa)} / First tensile strength (MPa)] × 100

[0308]

[0309] Experimental Example 3 - Decrease in elongation at break after exposure to a moisture environment

[0310] For each specimen manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, the first and second breaking elongations were measured under the same conditions as in Experimental Example 2.

[0311] The reduction rate of elongation at break was calculated according to Equation 2 below, and the results are shown in Table 2 below.

[0312] [Formula 2]

[0313] Breaking elongation reduction rate (%) = [{First breaking elongation (%) - Second breaking elongation (%)} / First breaking elongation (%)] × 100

[0314]

[0315] Experimental Example 4 - Elastic Recovery Rate

[0316] For each of the specimens manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, a Dynamic Mechanical Analyzer (DMA) TA 2980 / Q800 was used to raise the temperature to about 70°C, and then a stress of about 0.8 MPa was applied for about 60 minutes.

[0317] Afterwards, the stress was removed and the specimen was left for 20 minutes. The strain of the specimen was measured from the time the stress was removed to the time after the specimen was left for 20 minutes, and the results are shown in Table 2 below.

[0318]

[0319] Experimental Example 5 - Increase in yellowness after UV exposure

[0320] For each of the specimens manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, the first yellowness was measured using a colorimeter according to ASTM E313-2005.

[0321] Afterwards, the above specimen was placed in the QUV tester and exposed to 0.5 W / m 2 After irradiating with UV for 7 days under an illumination, the second yellowness was measured using the colorimeter.

[0322] The yellowness increase rate was calculated according to Equation 3 below, and the results are shown in Table 2 below.

[0323] [Formula 3]

[0324] Yellowness increase rate (%) = [{1st yellowness - 2nd yellowness} / 1st yellowness] × 100

[0325]

[0326] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Crystallization time 13.1 minutes 13.4 minutes 21.4 minutes 21.8 minutes 23.7 minutes 23.5 minutes Tensile strength reduction rate 18 % 15 % 12 % 15 % 45 % 18 % Elongation at break reduction rate 10 % 5 % 2 % 3 % 30 % 10 % Elastic recovery rate 71 % 70 % 69 % 70 % 85 % 83 % Yellowness increase rate 36 % 37 % 39 % 117 % 32 % 29 %

[0327]

[0328] Referring to Tables 1 and 2 above, it was confirmed that the biodegradable polyester resin compositions of Examples 1 to 3 had improved water resistance and a high mechanical property retention rate compared to the biodegradable polyester resin compositions of Comparative Examples 1 to 3. In addition, it was confirmed that the elastic recovery rate was reduced, which improved the plasticity characteristics and thus the processability, and that the yellowing phenomenon was reduced.

[0329] In addition, the biodegradable polyester resin compositions of Examples 1 to 3 can have an appropriate crystallization time, and thus can be manufactured into biodegradable molded products by a spinning process, an injection process, and a foaming process.

[0330] Meanwhile, Comparative Example 1 included a softening agent including polyether glycol, but did not include a yellowing inhibitor, so it was confirmed that the yellowing phenomenon was significantly increased.

[0331] In addition, Comparative Example 2 did not contain a softening agent, so yellowing did not occur significantly, but it was confirmed that it showed inferior effects in mechanical property retention rate and elastic recovery rate.

[0332] In addition, it was confirmed that Comparative Example 3 included a yellowing inhibitor but did not include a softening agent, so the elastic recovery rate was not improved and processability could still be a problem due to the high elastic properties.

[0333]

[0334] The present invention can be applied to a biodegradable polyester resin composition having excellent biodegradability, improved processability, and reduced yellowing, and to a biodegradable molded article comprising the same.

Claims

1. A biodegradable polyester resin comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit; A softener comprising polyether glycol; and A biodegradable polyester resin composition comprising a yellowing inhibitor.

2. In paragraph 1, A biodegradable polyester resin composition wherein the polyether glycol is selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and combinations thereof.

3. In paragraph 1, A biodegradable polyester resin composition wherein the polyether glycol has a number average molecular weight of 500 g / mol to 3,000 g / mol.

4. In paragraph 1, A biodegradable polyester resin composition having a softening agent content of 1,000 ppm to 100,000 ppm based on the total weight of the biodegradable polyester resin composition.

5. In paragraph 1, The above biodegradable polyester resin comprises a unit derived from the above softening agent, A biodegradable polyester resin composition having a content of the softening agent-derived unit of 750 ppm to 75,000 ppm based on the total weight of the biodegradable polyester resin.

6. In paragraph 1, A biodegradable polyester resin composition wherein the above yellowing inhibitor comprises at least one of a UV blocker, an antioxidant, and a light stabilizer.

7. In paragraph 1, A biodegradable polyester resin composition having a content of the above-mentioned yellowing inhibitor of 500 ppm to 50,000 ppm based on the total weight of the biodegradable polyester resin composition.

8. In paragraph 1, The above biodegradable polyester resin composition is a biodegradable polyester resin composition having an isothermal crystallization time of 10 to 22 minutes at 90°C according to the following measurement method 1: [Measurement Method 1] 1) The biodegradable polyester resin composition is heated to 220°C at a heating rate of 10°C / min, and then maintained for 5 minutes. 2) Afterwards, the biodegradable polyester resin composition is cooled to 90°C at a cooling rate of 100°C / min, and then maintained in an isothermal state for 100 minutes. 3) Using a differential scanning calorimeter, the time taken for the total area of ​​the crystallization peak of the biodegradable polyester resin composition to become half of the total area of ​​the crystallization peak of the biodegradable polyester resin composition is measured.

9. In paragraph 1, The above biodegradable polyester resin composition is a biodegradable polyester resin composition having a tensile strength reduction rate of 10% to 20% according to the following measurement method 2: [Measurement Method 2] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B. 2) The first tensile strength of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM). 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60 ℃ and 80 RH%, the second tensile strength is measured at a speed of 100 mm / min using the universal testing machine. 4) Calculate the tensile strength reduction rate according to Equation 1 below. [Formula 1] Tensile strength reduction rate (%) = [{First tensile strength (MPa) - Second tensile strength (MPa)} / First tensile strength (MPa)] × 100 10. In paragraph 1, The above biodegradable polyester resin composition is a biodegradable polyester resin composition having a reduction in elongation at break of 1% to 15% according to the following measurement method 3: [Measurement Method 3] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B. 2) The first breaking elongation of the above specimen is measured at a speed of 100 mm / min using a universal testing machine (UTM). 3) After the above specimen is subjected to accelerated aging for 8 days under conditions of 60°C and 80 RH%, the second breaking elongation is measured at a speed of 100 mm / min using the above universal testing machine. 4) Calculate the reduction rate of elongation at break according to Equation 2 below. [Formula 2] Breaking elongation reduction rate (%) = [{First breaking elongation (%) - Second breaking elongation (%)} / First breaking elongation (%)] × 100 11. In paragraph 1, The above biodegradable polyester resin composition is a biodegradable polyester resin composition having an elastic recovery rate of 30% to 80% according to the following measurement method 4: [Measurement Method 4] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B. 2) The above specimen is heated to 70°C using a dynamic mechanical analyzer (DMA), and then a stress of 0.8 MPa is applied for 60 minutes. 3) After removing the stress on the above specimen, leave it for 20 minutes. 4) Using the above DMA, the strain is measured from the time point at which the stress is removed to the time point after leaving the specimen for 20 minutes.

12. In paragraph 1, The biodegradable polyester resin composition above is a biodegradable polyester resin composition having a yellowness increase rate of 35% to 100% according to the following measurement method 5: [Measurement Method 5] 1) For the above biodegradable polyester resin composition, a specimen is prepared according to KSM 6518-B. 2) For the above specimen, the first yellowness is measured according to ASTM E313-2005. 3) Put the above specimen into the QUV tester and apply 0.5 W / m 2 After irradiating with UV for 7 days under high light, the second yellowness is measured according to ASTM E313-2005. 4) Calculate the yellowness increase rate according to Equation 3 below. [Formula 3] Yellowness increase rate (%) = [{1st yellowness - 2nd yellowness} / 1st yellowness] × 100 13. Biodegradable polyester resin comprising a diol-derived unit, an aliphatic dicarboxylic acid-derived unit, and an aromatic dicarboxylic acid-derived unit; A softener comprising polyether glycol; and A biodegradable molded article comprising a biodegradable polyester resin composition comprising a yellowing inhibitor.

14. In paragraph 13, The above biodegradable molded product is a biodegradable molded product that is a non-woven fabric, injection molded product, or foam molded product.

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