Biodegradable polyester resin and preparing method thereof

Abstract

Provided are a biodegradable polyester resin composition, a preparing method thereof, and a biodegradable polyester film prepared from the composition, the composition comprising a resin, which includes a residue of a dicarboxylic acid component and a residue of a diol component, and satisfying equation 1. By satisfying equation 1, the productivity and processability of the biodegradable polyester resin composition are improved such that the tensile strength, elongation, and tear strength of the biodegradable polyester film can be enhanced. [Equation 1] In equation 1, G' is a storage modulus at a temperature of 190℃ and a frequency of 10 rad / s to 100 rad / s in dynamic viscoelasticity measurement, and G'' is a loss modulus at a temperature of 190℃ and a frequency of 10 rad / s to 100 rad / s in dynamic viscoelasticity measurement.

Description

Biodegradable polyester resin and method for producing the same

[0001] The present disclosure relates to a biodegradable polyester resin and a method for producing the same.

[0002] Polyester resins are polymers with ester (RO-C(=O)-R') functional groups in their main chains. They are used in a variety of industrial applications, including packaging, displays, and insulating materials. Recently, with environmental protection issues in mind, research into biodegradable polyester compositions has been ongoing.

[0003] In general, a biodegradable polyester composition is manufactured using aliphatic dicarboxylic acid, aromatic dicarboxylic acid, and aliphatic diol as main raw materials, and branching agents, catalysts, and heat stabilizers as auxiliary raw materials.

[0004] Specifically, the biodegradable polyester resin is manufactured by subjecting the main raw material to an esterification reaction and a polycondensation reaction in the presence of the auxiliary raw material, and in some cases, a chain extension reaction is performed after the polycondensation reaction to enhance the mechanical properties of the biodegradable polyester resin. In addition, the properties of the final biodegradable polyester resin may vary depending on the characteristics of the raw material mixture during the manufacture of the biodegradable polyester.

[0005] According to one embodiment, a biodegradable polyester resin composition having excellent processability and mechanical properties is provided.

[0006] According to another embodiment, a method for producing a biodegradable polyester resin composition is provided, which can improve the productivity and processability of the biodegradable polyester resin composition.

[0007] A biodegradable polyester resin composition according to one embodiment comprises a resin including a residue of a dicarboxylic acid component and a residue of a diol component, and satisfies the following formula 1:

[0008] [Formula 1]

[0009]

[0010] In the above equation 1, G' is the storage modulus in the temperature range of 190°C and the frequency range of 10 rad / s to 100 rad / s in the dynamic viscoelasticity measurement, and G” is the loss modulus in the temperature range of 190°C and the frequency range of 10 rad / s to 100 rad / s in the dynamic viscoelasticity measurement.

[0011] The above dicarboxylic acid component includes an aromatic dicarboxylic acid having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, and the aromatic dicarboxylic acid having 6 to 12 carbon atoms may include terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof, and the aliphatic dicarboxylic acid having 4 to 10 carbon atoms may include adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivatives thereof, anhydrides thereof, or mixtures thereof.

[0012] The above dicarboxylic acid component may include 30 mol% to 70 mol% of an aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 mol% to 70 mol% of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the above dicarboxylic acid component.

[0013] The above diol includes an aliphatic diol having 2 to 10 carbon atoms, and the aliphatic diol having 2 to 10 carbon atoms may include 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl, 1,3-propanediol, cyclic aliphatic diols, or mixtures thereof.

[0014] The molar ratio of the above dicarboxylic acid component and the above diol component is 1.0:0.8 to 1.0:1.2.

[0015] The complex viscosity change rate before and after an oscillatory time sweep for 10 minutes at a temperature of 190℃ and a frequency of 20 rad / s is less than 15%.

[0016] The above biodegradable polyester resin composition has a melt flow index (MI) of 10 g / 10 min or less measured at 190°C under a load of 2.16 kg according to ASTM D1238.

[0017] A method for producing a biodegradable polyester resin composition according to another embodiment comprises: a first step of producing a raw material mixture including an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol; a second step of reacting the raw material mixture to produce an oligomer; a third step of polycondensing the oligomer to produce a prepolymer; and a fourth step of adding a chain extender to the prepolymer to obtain a biodegradable polyester resin composition; wherein the raw material mixture of the first step has a moisture content of 3000 ppm or less, and the biodegradable polyester resin composition produced in the fourth step satisfies the above formula 1.

[0018] The particle size dispersion index (SPAN) of the above aromatic dicarboxylic acid is 5.0 or less.

[0019] In the third step, the reaction conversion rate of the oligomer is expressed by the following equation 2, and the reaction conversion rate is 90% to 100%:

[0020] [Formula 2]

[0021] Conversion rate (%) =

[0022] In the above equation 2,

[0023] AV is the acid value expressed by the following equation 2-1,

[0024] SV is the saponification value expressed by the following equation 2-2:

[0025] [Formula 2-1]

[0026] Mountain (AV) =

[0027] In the above equation 2-1, A is the appropriate volume (ml) of 0.1 N sodium hydroxide solution, P is the titer of 0.1 N sodium hydroxide solution, and W is the mass of the oligomer:

[0028] [Formula 2-2]

[0029] Saponification Value (SV) =

[0030] In the above equation 2-2, B is the titrant volume (ml) of a 0.5 N hydrochloric acid solution (HCl), C is the titrant volume (ml) of a blank solution, Q is the titrant of a 0.5 N hydrochloric acid solution, and W' is the mass of the oligomer.

[0031] The above aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, a diester derivative thereof, an anhydride thereof, or a combination thereof, and the above aliphatic dicarboxylic acid is adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivative thereof, an anhydride thereof, or a combination thereof.

[0032] Based on the total mole number of the above raw material mixture, the aromatic dicarboxylic acid may be included in an amount of 20 mol% to 50 mol%, and the aliphatic dicarboxylic acid may be included in an amount of 20 mol% to 50 mol%.

[0033] The above aliphatic diol is 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl, 1,3-propanediol, cyclic aliphatic diols, or a combination thereof.

[0034] The aliphatic diol may be included in an amount of 30 mol% to 60 mol% based on the total mole number of the raw material mixture.

[0035] The molar ratio of the above aromatic dicarboxylic acid and aliphatic dicarboxylic acid and the above aliphatic diol is 1.0:0.8 to 1.0:1.2.

[0036] According to another embodiment, a biodegradable polyester film can be obtained by melt-extruding the biodegradable polyester resin composition described above with a blown film extruder, and can be obtained by melt-extruding the biodegradable polyester resin composition produced by the above-described production method with a blown film extruder.

[0037] A polyester resin composition according to one embodiment can have improved productivity and processability.

[0038] A method for manufacturing a polyester resin composition according to another embodiment can uniformly control the reaction rate of each process and suppress side reactions.

[0039] A polyester film manufactured from a polyester resin composition according to one embodiment can secure excellent tensile strength, elongation, and tear strength.

[0040] Figure 1 is a graph showing values ​​corresponding to the area of ​​the storage elastic modulus and the area of ​​the loss elastic modulus measured at 10 rad / s to 100 rad / s of the compositions according to the examples and comparative examples.

[0041] The advantages and features of the technology described below, as well as the methods for achieving them, will become clearer with reference to the detailed implementation examples described below together with the attached drawings. However, the form of implementation may not be limited to the implementation examples disclosed below. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning that can be commonly understood by those of ordinary skill in the relevant technical field. In addition, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined.

[0042] Throughout this specification, whenever a part is referred to as "comprising" a certain component, this does not exclude other components, but rather includes other components, unless otherwise stated. Furthermore, the singular includes the plural unless specifically stated otherwise.

[0043] Based on the above definitions, implementation examples of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0044]

[0045] [Biodegradable polyester resin composition]

[0046] A biodegradable polyester resin composition according to one embodiment comprises a resin including a residue of a dicarboxylic acid component and a residue of a diol component, and satisfies the following formula 1.

[0047] [Formula 1]

[0048]

[0049] In the above equation 1, G' is the storage modulus in the temperature range of 190°C and the frequency range of 10 rad / s to 100 rad / s in the dynamic viscoelasticity measurement, and G” is the loss modulus in the temperature range of 190°C and the frequency range of 10 rad / s to 100 rad / s in the dynamic viscoelasticity measurement.

[0050] In one embodiment, the storage modulus (G') and the loss modulus (G") are measured by mounting a 25 mm parallel plate on a rotational rheometer (TA HR-2).

[0051] In the above formula 1 is the integral of the storage modulus measured by performing a frequency sweep in the frequency range of 10 rad / s to 100 rad / s at a temperature of 190℃. It refers to the integral value of the loss modulus measured by performing a frequency sweep in the frequency range of 10 rad / s to 100 rad / s at a temperature of 190℃.

[0052] Specifically, the integral of the storage modulus in the frequency range of 10 rad / s to 100 rad / s at a temperature of 190°C divided by the integral of the loss modulus under the same conditions is 0.1 to 2.0, for example, 0.1 to 1.75, for example, 0.1 to 1.50, for example, 0.15 to 1.5, for example, 0.20 to 1.5, for example, 0.25 to 1.5, for example, 0.3 to 1.5, for example, 0.4 to 1.5, for example, 0.50 to 1.5, for example, 0.50 to 1.3, for example, 0.50 to 1.0, and is not limited thereto.

[0053] Since the biodegradable polyester resin composition satisfies the above formula 1, the productivity and processability of the composition can be improved, and the tensile strength, elongation, and tear strength of the biodegradable polyester film manufactured therefrom can be improved.

[0054] In one embodiment, the dicarboxylic acid component included in the biodegradable polyester resin composition includes an aromatic dicarboxylic acid having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

[0055] The above aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or combinations thereof, for example, but not limited to, terephthalic acid, isophthalic acid, diester derivatives thereof, or combinations thereof.

[0056] The above aliphatic dicarboxylic acid is adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivative thereof, an anhydride thereof, or a combination thereof, for example, but not limited to, adipic acid, succinic acid, a diester derivative thereof, or a combination thereof.

[0057] In one embodiment, the dicarboxylic acid component may include 30 mol% to 70 mol% of the aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 mol% to 70 mol% of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the dicarboxylic acid component.

[0058] In one embodiment, the aliphatic diol is, but is not limited to, 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl,1,3-propanediol, cyclic aliphatic diols, or combinations thereof.

[0059] In one embodiment, the molar ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid and the aliphatic diol included in the biodegradable polyester resin composition is 1.0:0.8 to 1.0:1.2, for example, 1.0:0.8 to 1.0:1.15, for example, 1.0:1.1, but is not limited thereto.

[0060] A biodegradable polyester resin composition according to one embodiment has a complex viscosity change rate of less than 15% before and after an oscillatory time sweep for 10 minutes at a temperature of 190°C and a frequency of 20 rad / s.

[0061] The above complex viscosity can be measured using a rotational rheometer (TA HR-2), and the complex viscosity change rate can be obtained by measuring the complex viscosity values ​​before and after performing a vibration time sweep for 10 minutes at an angular frequency of 20 rad / s. Specifically, the complex viscosity change rate can be obtained as [(complex viscosity value after 10 minutes - initial complex viscosity value) / initial complex viscosity value] X 100(%).

[0062] In one embodiment, the complex viscosity change rate is less than 15%, for example, less than 13%, for example, less than 11%, for example, less than 9%, for example, less than 6%, but is not limited thereto. In addition, the complex viscosity change rate is greater than or equal to 0.5%, for example, greater than or equal to 1.0%, for example, greater than or equal to 1.5%, but is not limited thereto.

[0063] Since the biodegradable polyester resin composition has a complex viscosity change rate within the above range, the productivity and processability of the composition can be improved, and the tensile strength, elongation, and tear strength of a biodegradable polyester film manufactured therefrom can be improved.

[0064] In one embodiment, the biodegradable polyester resin composition has a melt flow index (MI) of 10 g / 10 min or less as measured at 190°C under a load of 2.16 kg according to ASTM D1238. The melt flow index is 10 g / 10 min or less, for example, 8 g / 10 min or less, for example, 6 g / 10 min or less, for example, 5 g / 10 min or less, but is not limited thereto. When the melt flow index satisfies the above range, the productivity and processability of the composition can be improved, and the tensile strength, elongation, and tear strength of the biodegradable polyester film manufactured therefrom can be improved.

[0065]

[0066] [Method for producing a biodegradable polyester composition]

[0067] According to another embodiment, a method for producing a biodegradable polyester resin composition comprises: a first step of producing a raw material mixture including an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol; a second step of reacting the raw material mixture to produce an oligomer; a third step of polycondensing the oligomer to produce a prepolymer; and a fourth step of adding a chain extender to the prepolymer to obtain a biodegradable polyester resin composition; wherein the raw material mixture of the first step has a moisture content of 3000 ppm or less, and the biodegradable polyester resin composition produced in the fourth step satisfies the above formula 1.

[0068] The biodegradable polyester resin composition manufactured by the above manufacturing method may be the same as the above-described embodiment, and any description overlapping with the above-described content will be omitted below, and the manufacturing method of the above-described embodiment will be described step by step.

[0069]

[0070] Step 1

[0071] In the first step, a raw material mixture including an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol is prepared.

[0072] The moisture content contained in the above raw material mixture is measured using a Karl Fischer Tritrator, and specifically, the moisture content (%) is calculated using the following equation 3 by titrating with a Karl Fischer Reagent (KFR).

[0073] [Formula 3]

[0074]

[0075] In the above equation 3, T is the volume (ml) of Karl Fischer reagent consumed in sample titration, S is the volume (ml) of Karl Fischer reagent consumed in blank titration, R is the titer (mg / ml) of Karl Fischer reagent, and M is the mass (mg) of the sample.

[0076] In one embodiment, the moisture content of the raw material mixture is 3000 ppm or less, for example, 2900 ppm or less, for example, 2800 ppm or less, for example, 2600 ppm or less, for example, 2200 ppm or less, but is not limited thereto. In addition, the moisture content of the raw material mixture is 1400 ppm or more, for example, 1500 ppm or more, but is not limited thereto.

[0077] If the moisture content of the raw material mixture does not satisfy the above range, the catalytic activity may be reduced during the manufacturing process of the resin composition and hydrolysis of the resin composition may be induced, thereby deteriorating the physical properties of the biodegradable polyester resin film formed therefrom. By satisfying the moisture content of the raw material mixture within the above range, the biodegradable polyester resin composition may be uniform.

[0078] In one embodiment, the particle size dispersion index (SPAN) of the aromatic dicarboxylic acid included in the raw material mixture is 5.0 or less, for example, 4.5 or less, for example, 4.0 or less, for example, 3.5, but is not limited thereto. In addition, the particle size dispersion index of the aromatic dicarboxylic acid is 0.5 or more, for example, 1.0 or more, for example, 1.5 or more, but is not limited thereto.

[0079] The particle size dispersion index (SPAN) of the above aromatic dicarboxylic acid can be measured using a particle size analyzer (Beckman Coulter, LS13320 XR, Dry powder module).

[0080] Since the particle size dispersion index of the aromatic dicarboxylic acid falls within the above range, the biodegradable polyester resin composition can be uniform.

[0081] In one embodiment, the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, a diester derivative thereof, an anhydride thereof, or a combination thereof, for example, but not limited to, terephthalic acid, isophthalic acid, a diester derivative thereof, or a combination thereof.

[0082] In one embodiment, the aliphatic dicarboxylic acid is adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivative thereof, an anhydride thereof, or a combination thereof, for example, but not limited to, adipic acid, succinic acid, a diester derivative thereof, or a combination thereof.

[0083] In one embodiment, the aromatic dicarboxylic acid is present in an amount of 20 mol% to 50 mol% based on the total moles of the raw material mixture, for example, 20 mol% to 45 mol%, for example, 20 mol% to 40 mol%, for example, 20 mol% to 35 mol%, for example, 20 mol% to 30 mol%, but is not limited thereto.

[0084] In one embodiment, the aliphatic dicarboxylic acid is present in an amount of 20 mol% to 50 mol% based on the total moles of the raw material mixture, for example, 20 mol% to 45 mol%, for example, 20 mol% to 40 mol%, for example, 20 mol% to 35 mol%, for example, 20 mol% to 30 mol%, but is not limited thereto.

[0085] In one embodiment, the aliphatic diol is, but is not limited to, 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl,1,3-propanediol, cyclic aliphatic diols, or combinations thereof.

[0086] In one embodiment, the aliphatic diol is present in an amount of 30 mol% to 60 mol% based on the total moles of the raw material mixture, for example, 30 mol% to 55 mol%, for example, 35 mol% to 55 mol%, for example, 40 mol% to 60 mol%, for example, 40 mol% to 55 mol%, for example, 50 mol%, but is not limited thereto.

[0087] In one embodiment, the molar ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid to the aliphatic diol is from 1.0:0.8 to 1.0:1.2, for example from 1.0:0.8 to 1.0:1.15, for example from 1.0:1.1, but is not limited thereto.

[0088] In another embodiment, the raw material mixture may additionally include compounds to improve the properties of the biodegradable polyester resin composition, such as a branching agent and a catalyst.

[0089] For example, the branching agent may include a hydroxyl group (-OH), a carboxyl group (-COOH), or an anhydride as a crosslinkable functional group. Specifically, the branching agent may include glycerol, trimethylolpropane, pentaerythritol, and the like. The branching agent may be added not only in the first step, but also in the latter part of the second step or the latter part of the third step.

[0090] For example, the catalyst may be a titanium (Ti)-based catalyst, and the titanium (Ti)-based catalyst may include a titanium (Ti)-based esterification catalyst, a titanium (Ti)-based polycondensation catalyst, or a combination thereof. The titanium (Ti)-based esterification catalyst may include an organic acid chelate titanium compound, an inorganic titanium compound. The titanium (Ti)-based polycondensation catalyst may include a titanium tetraalkoxide compound, or a combination thereof.

[0091] By further including a titanium (Ti) catalyst in the raw material mixture, oligomers of uniform size can be manufactured, thereby preventing unreaction.

[0092]

[0093] Step 2

[0094] In the second step, the raw material mixture is reacted to produce an oligomer. To prevent thermal decomposition in the second step, the reaction must be carried out efficiently in a short period of time. If the temperature at which the second step is performed is too low, the residence time may be long and unreacted products may be generated. If the reaction temperature is too high, the diol among the reactants, particularly 1,4-butanediol, decomposes to produce THF, so 1,4-butanediol cannot sufficiently participate in the reaction, which may result in unreacted products being generated.

[0095] The second step is performed at a temperature range of 190°C to 230°C, thereby minimizing large molecules or aggregates within the final biodegradable polyester composition. Specifically, in the second step, the esterification reaction of the raw material mixture is carried out by applying a low vacuum at a temperature range of 190°C to 230°C, and byproducts such as water (H2O) and side reactions are removed from the system through a rectification column to obtain an oligomer.

[0096] In one embodiment, the reaction conversion rate of the oligomer in the above 2nd step is expressed by the following equation 2, and the reaction conversion rate is 90% to 100%.

[0097] [Formula 2]

[0098] Conversion rate (%) =

[0099] In the above formula 2, AV (Acid Value) is the acid value expressed by the following formula 2-1, and SV (Saponification value) is the saponification value expressed by the following formula 2-2:

[0100] [Formula 2-1]

[0101] Mountain (AV) =

[0102] In the above equation 2-1, A is the appropriate volume (ml) of 0.1 N sodium hydroxide solution, P is the titer of 0.1 N sodium hydroxide solution, and W is the mass (g) of the oligomer:

[0103] [Formula 2-2]

[0104] Saponification Value (SV) =

[0105] In the above equation 2-2, B is the titrant volume (ml) of a 0.5 N hydrochloric acid solution (HCl), C is the titrant volume (ml) of a blank solution, Q is the titer of a 0.5 N hydrochloric acid solution, and W' is the mass (g) of the oligomer.

[0106] The reaction conversion of the above oligomer is 90% to 100%, for example, 91% to 100%, for example, 93% to 100%, for example, 95% to 100%, for example, 96% to 100%, but is not limited thereto.

[0107] Since the reaction conversion rate of the above oligomer satisfies the above range, the reaction speed of the manufacturing process can be uniformly controlled, and side reactions can be suppressed, so that the biodegradable polyester resin composition can be uniform.

[0108]

[0109] Step 3

[0110] In the third step, the oligomer can be polycondensed to produce a prepolymer. To prevent thermal decomposition in the third step, the reaction can be efficiently performed in a short period of time. If the temperature at which the third step is performed is too high, the thermal decomposition reaction may dominate over the polycondensation reaction, resulting in the production of decomposition products and prolonged residence times.

[0111] In this regard, the third step is performed under a vacuum of 1 Torr or less at a temperature range of 210°C to 250°C, thereby minimizing by-products generated by thermal decomposition within the final biodegradable polyester composition.

[0112] Accordingly, a prepolymer having a melt flow index (MI) of 5 g / 10 min to 60 g / 10 min measured at 190°C under a load of 2.16 kg according to ASTM D1238 standard can be obtained.

[0113] In one embodiment, the third step may further include adding a heat stabilizer to cause the reaction.

[0114] For example, the heat stabilizer may be a phosphorus (P)-based heat stabilizer, such as trimethyl phosphonoacetate, triethyl phosphonoacetate, phosphoric acid, phosphorous acid, polyphosphric acid, trimethyl phosphate (TMP), triethyl phosphate, trimethyl phosphine, triphenyl phosphine, or a combination thereof.

[0115] By adding the above-mentioned P-type thermal stabilizer, thermal decomposition can be prevented without reducing the activity of the catalyst.

[0116]

[0117] Step 4

[0118] In the fourth step, a chain extender can be added to the prepolymer to further increase viscosity, thereby obtaining a polyester resin composition.

[0119] In the fourth step, if the prepolymer and the chain extender are mixed at a high speed or with high shear for smooth reaction, the shear stress may increase, which may cause decomposition. If the reaction is performed at a high temperature, thermal decomposition may occur, which rapidly increases the molecular weight distribution of the final biodegradable polyester.

[0120] Therefore, it is preferable that the fourth step is performed using a static mixer or a dynamic mixer at a temperature range of 120°C to 250°C for 0 to 30 minutes.

[0121]

[0122] [Biodegradable polyester film]

[0123] A biodegradable polyester film according to another embodiment can be obtained by melt-extruding the biodegradable polyester resin composition described above with a blown film extruder, and a biodegradable polyester film according to another embodiment can be obtained by melt-extruding the biodegradable polyester resin composition produced by the above-described production method with a blown film extruder, and the production process of the biodegradable polyester film is not limited thereto.

[0124] The biodegradable polyester film obtained above has a thickness of 30 µm to 70 µm, for example, 30 µm to 60 µm, for example, 40 µm to 70 µm, for example, 40 µm to 60 µm, for example, 50 µm, but is not limited thereto.

[0125]

[0126] Hereinafter, the present invention will be described with reference to examples, but the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited to these examples.

[0127]

[0128] Preparation of biodegradable polyester resin composition

[0129] Example 1

[0130] Step 1: Prepare a raw material mixture by stirring 24 mol% of terephthalic acid (TPA), 26 mol% of adipic acid (AA), and 50 mol% of 1,4-butanediol (1,4-BDO). The particle size dispersion index (SPAN) of the terephthalic acid and the moisture content of the raw material mixture are as shown in Table 1 below.

[0131] Step 2: To the raw material mixture of Step 1, a titanium-based catalyst, tetrabutyl titanate, is added and the resulting effluent is removed through a distillation column at a low vacuum of 220°C and 650 mbar, thereby producing an oligomer. The reaction conversion rate of the oligomer in Step 2 is as shown in Table 1 below.

[0132] Step 3: The reaction mixture obtained through the above step 2 is heated to 250°C and then subjected to condensation polymerization at 1 torr or less, and the reaction is terminated when the discharge load is reached, thereby obtaining a prepolymer having a number average molecular weight of 35,000 g / mol.

[0133] Step 4: After drying the obtained biodegradable polyester prepolymer, a chain extension process is performed using a mixer to obtain a final biodegradable polyester resin composition having the characteristics shown in Table 2 below.

[0134]

[0135] Examples 2 to 6

[0136] A biodegradable polyester resin composition is manufactured by changing the properties of raw materials as shown in Table 1 below.

[0137]

[0138] Comparative Examples 1 to 4

[0139] A biodegradable polyester resin composition is manufactured by changing the properties of raw materials as shown in Table 1 below.

[0140]

[0141] Experimental Example 1: Physical properties of raw material mixture

[0142] Moisture content in the raw material mixture: Using a Karl Fischer Tritrator, titrate with Karl Fischer Reagent (KFR) to calculate the moisture content (%) using the following equation 3.

[0143] [Formula 3]

[0144]

[0145] In the above equation 3, T is the volume (ml) of Karl Fischer reagent consumed in the sample titration, S is the volume (ml) of Karl Fischer reagent consumed in the blank titration, R is the titer (mg / ml) of Karl Fischer reagent, and M is the mass (mg) of the raw material mixture sample.

[0146] Particle size dispersion index (SPAN) of aromatic dicarboxylic acid: Measured using a particle size analyzer (Beckman Coulter, LS13320 XR, Dry powder module), and SPAN is calculated using the following equation 4.

[0147] [Formula 4]

[0148] SPAN = (D90-D10) / D50

[0149] In the above equation 4, D90 refers to a particle size at which the volume accumulation corresponds to 90% from the side with a small particle size in the cumulative curve of the particle size distribution, D10 refers to a particle size at which the volume accumulation corresponds to 10% from the side with a small particle size, and D50 refers to a particle size at which the volume accumulation corresponds to 50% from the side with a small particle size.

[0150]

[0151] Experimental Example 2: Measurement of the reaction conversion rate of oligomers

[0152] Measurement of acidity value (AV)

[0153] A sample solution containing 50 ml of dimethylformamide (DMF) was prepared by injecting 0.2 g of each of the oligomer samples of Examples 1 to 6 and Comparative Examples 1 to 4, and a 50 ml solvent of dimethylformamide (hereinafter, referred to as a base solution) without the sample was prepared. Dissolve in an ultrasonic dissolution bath at 85°C to 90°C for 1 hour and then cool to room temperature. Add 2 to 3 drops of 0.1% rosolic acid to each of the sample solution and the base solution, and titrate with N / 10-NaOH methanol solution. The end point is when the color changes from pale yellow to light purple, and the acid value is calculated using the following equation 2-1:

[0154] [Formula 2-1]

[0155] Mountain (AV) =

[0156] In the above equation 2-1, A is the appropriate volume (ml) of 0.1 N sodium hydroxide solution, P is the titer of 0.1 N sodium hydroxide solution, and W is the mass (g) of the oligomer.

[0157] Measurement of saponification value (SV)

[0158] Inject 20 ml of 0.5 N KOH alcohol solution into each of 0.4 g of the oligomer samples of Examples 1 to 6 and Comparative Examples 1 to 4, add 2 to 3 boiling stones, and prepare a sample solution. In addition, prepare a blank solution by adding 2 to 3 boiling stones into 20 ml of 0.5 N KOH alcohol solution excluding the sample. The sample solution and blank solution are hydrolyzed in a 110°C oil bath equipped with a cooling condenser for 40 minutes. Inject 15 ml of distilled water, mix thoroughly, and cool to room temperature. Then, add 3 to 4 drops of 0.1% phenolphthalein to each of the sample solution and blank solution, and titrate with 0.5 N HCl. The end point refers to when the color changes from pink to colorless, and the saponification value is calculated using the following equation 2-2:

[0159] [Formula 2-2]

[0160] Saponification Value (SV) =

[0161] In the above equation 2-2, B is the titrant volume (ml) of a 0.5 N hydrochloric acid solution (HCl), C is the titrant volume (ml) of a blank solution, Q is the titer of a 0.5 N hydrochloric acid solution, and W' is the mass (g) of the oligomer.

[0162] Deriving the reaction conversion rate (%)

[0163] The acid value (AV) and saponification value (SV) obtained above are applied to Equation 2 below to obtain the reaction conversion rate of the oligomer:

[0164] [Formula 2]

[0165] Conversion rate (%) =

[0166] The reaction conversion rates of the oligomers obtained by the above method are as shown in Table 1 below:

[0167] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 1,4-BDO (mol%) 50 50 50 50 50 50 50 50 50 TPA (mol%) 24 24 24 24 24 24 24 24 24 AA (mol%) 26 26 26 26 26 26 26 26 SPAN of TPA 1.79 3.11 2.0 7 2.6 4 2.7 1.8 7 5.5 4 8.9 32.3 3 2.5 In the raw material mixture Moisture content (ppm) 1480 1610 2850 1560 2130 2540 2080 1350 5000 5000 Reaction conversion rate (%) 98.49 8.99 8.79 6.49 1.59 9.99 7.0 98.19 3.18 3.4

[0168]

[0169] Experimental Example 3: Physical properties of biodegradable polyester resin composition

[0170] The physical properties of the biodegradable polyester resin compositions of the examples and comparative examples were evaluated by the following method, and the results are as shown in Table 2 below.

[0171] Melt Index (MI): Based on ASTM D1238 standard, the weight of polyester extruded through the extrusion viscometer orifice at 190℃ for 10 minutes under a load of 2.16 kg after loading the sample is measured.

[0172] Molecular weight distribution (PDI): Measured by gel permeation chromatography (GPC, Agilent, Technology 1200 Series), using chloroform as the solvent and polystyrene as the standard. The column and detector temperatures were set to 40°C, and the flow rate was 1 mL / min.

[0173] Zero Shear Viscosity (η0): This refers to the complex viscosity at each frequency of 0.1 rad / s obtained by performing a Frequency Sweep Test with 1% strain.

[0174] Cumulative storage modulus (Cot δ): A rotational rheometer (TA HR-2) with a 25 mm parallel plate is mounted, and a frequency sweep is performed at a temperature of 190°C and a frequency range of 10 rad / s to 100 rad / s to measure the storage modulus and loss modulus. Fig. 1 is a graph showing the storage modulus and loss modulus of the examples and comparative examples. The cumulative storage modulus is the value obtained by dividing the integral of the storage modulus in the frequency range of 10 rad / s to 100 rad / s by the integral of the loss modulus, and is as shown in Equation 1-1 below.

[0175] [Formula 1-1]

[0176]

[0177] Complex viscosity change rate: Measured using a rotational rheometer (TA HR-2), and calculated as the viscosity change rate compared to the initial viscosity when performing a Time Sweep Test for 10 minutes with a fixed angular frequency of 20 rad / s and strain of 1%. Specifically, the complex viscosity change rate is calculated as [(complex viscosity value after 10 minutes - initial complex viscosity value) / initial complex viscosity value] X 100 (%).

[0178]

[0179] Experimental Example 4: Physical properties of biodegradable polyester film

[0180] The biodegradable polyester resin compositions obtained in the above examples and comparative examples were melt-extruded using a blown film extruder to produce a 50 μm biodegradable polyester film, and the physical properties were evaluated by the following method, and the results are as shown in Table 2 below.

[0181] Tensile strength: This refers to the degree of resistance of the film to tearing. Tensile strength is measured using INSTRON's universal testing machine 5965 based on the ASTM D882 standard.

[0182] Elongation: Elongation is measured using INSTRON's universal testing machine 5965 based on ASTM D882 standard.

[0183] Tear Strength: Tear strength is measured using an Elmendorf tear tester from Thwing-Albert instrument company based on ASTM D1922 standard.

[0184] Evaluation Items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Resin Composition MI (g / 10min) 32.7 3.5 3.33 13.4 2.8 3.13 PDI 1.89 2.0 12.2 2.14 1.98 2.17 2.56 3.0 12.6 12.75 Zero Viscosity (Pa.s) 40 59 44 25 34 7 33 8 6 33 5 9 8 36 9 6 36 30 46 7 2 3 7 4 12 9 0 Cumulative Storage Coefficient 0.78 30.83 6 0.79 8 0.85 2 0.98 8 0.75 4 1.68 0 2.46 2 1.74 2 0.079 Complex Viscosity Change rate (%) 2.43.42.13.65.61.610.518.716.020.6Film tensile strength (kgf / ㎠) 558487523508492560338301325320Elongation (%) 470463460455456468435428431438Tear strength (g / ㎛) 3.43.13.43.12.83.52.41.11.71.3

[0185] Referring to Table 2 above, it can be confirmed that the biodegradable polyester resin composition according to the example has a cumulative storage coefficient of 0.1 to 1.5 and a complex viscosity change rate (%) of less than 6%. It can be confirmed that the biodegradable polyester film according to the example has better tensile strength, elongation, and tear strength than the biodegradable polyester film according to the comparative example.

[0186] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. A biodegradable polyester resin composition comprising a resin containing a residue of a dicarboxylic acid component and a residue of a diol component, and satisfying the following formula 1: [Formula 1] In the above equation 1, G' is the storage modulus in the range of temperature 190℃ and frequency 10 rad / s to 100 rad / s in dynamic viscoelasticity measurements, “G” is the loss modulus in the temperature range of 190℃ and frequency range of 10 rad / s to 100 rad / s in dynamic viscoelasticity measurements.

2. In the first paragraph, the dicarboxylic acid component includes an aromatic dicarboxylic acid having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, The aromatic dicarboxylic acid having 6 to 12 carbon atoms includes terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, diester derivatives thereof, anhydrides thereof, or mixtures thereof. A biodegradable polyester resin composition comprising the aliphatic dicarboxylic acid having 4 to 10 carbon atoms, adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivative thereof, an anhydride thereof, or a mixture thereof.

3. In the first paragraph, the dicarboxylic acid component is a biodegradable polyester resin composition comprising 30 mol% to 70 mol% of an aromatic dicarboxylic acid having 6 to 12 carbon atoms and 30 mol% to 70 mol% of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, based on the total amount of the dicarboxylic acid component.

4. In the first paragraph, the diol comprises an aliphatic diol having 2 to 10 carbon atoms, A biodegradable polyester resin composition comprising the aliphatic diol having 2 to 10 carbon atoms, wherein the aliphatic diol is 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl, 1,3-propanediol, cyclic aliphatic diols, or a mixture thereof.

5. A biodegradable polyester resin composition in paragraph 1, wherein the molar ratio of the dicarboxylic acid component and the diol component is 1.0:0.8 to 1.0:1.

2.

6. A biodegradable polyester resin composition having a complex viscosity change rate of less than 15% before and after an oscillatory time sweep for 10 minutes at a temperature of 190°C and a frequency of 20 rad / s in the first paragraph.

7. In the first paragraph, the biodegradable polyester resin composition has a melt flow index (MI) of 10 g / 10 min or less measured at 190°C under a load of 2.16 kg according to ASTM D1238.

8. A first step of preparing a raw material mixture comprising an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol; A second step of producing an oligomer by reacting the above raw material mixture; A third step of producing a prepolymer by condensing the above oligomer; and A fourth step of obtaining a biodegradable polyester resin composition by adding a chain extender to the above prepolymer; The moisture content of the raw material mixture of the first step is 3000 ppm or less, The biodegradable polyester resin composition manufactured in the above 4th step is a method for manufacturing a biodegradable polyester resin composition that satisfies the following formula 1: [Formula 1] In the above equation 1, G' is the storage modulus in the range of temperature 190℃ and frequency 10 rad / s to 100 rad / s in dynamic viscoelasticity measurements, “G” is the loss modulus in the temperature range of 190℃ and frequency range of 10 rad / s to 100 rad / s in dynamic viscoelasticity measurements.

9. A method for producing a biodegradable polyester resin composition in accordance with claim 8, wherein the particle size dispersion index (SPAN) of the aromatic dicarboxylic acid is 5.0 or less.

10. In the 8th paragraph, the reaction conversion rate of the oligomer in the third step is expressed by the following equation 2, and the method for producing a biodegradable polyester resin composition having the reaction conversion rate of 90% to 100%: [Formula 2] Conversion rate (%) = In the above equation 2, AV is the acid value expressed by the following equation 2-1, SV is the saponification value expressed by the following equation 2-2: [Formula 2-1] 산가(AV)= In the above equation 2-1, A is the appropriate volume (ml) of 0.1 N sodium hydroxide solution, P is the titer of 0.1 N sodium hydroxide solution, and W is the mass of the oligomer: [Formula 2-2] Saponification Value (SV) = In the above equation 2-2, B is the titrant volume (ml) of a 0.5 N hydrochloric acid solution (HCl), C is the titrant volume (ml) of a blank solution, Q is the titrant of a 0.5 N hydrochloric acid solution, and W' is the mass of the oligomer.

11. A method for producing a biodegradable polyester resin composition in claim 8, wherein the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, furandicarboxylic acid, naphthalenedicarboxylic acid, a diester derivative thereof, an anhydride thereof, or a combination thereof, and the aliphatic dicarboxylic acid is adipic acid, succinic acid, glutaric acid, azelaic acid, sebacic acid, a cyclic fatty acid, a diester derivative thereof, an anhydride thereof, or a combination thereof.

12. A method for producing a biodegradable polyester resin composition, wherein the aromatic dicarboxylic acid is contained in an amount of 20 mol% to 50 mol% and the aliphatic dicarboxylic acid is contained in an amount of 20 mol% to 50 mol% based on the total mole number of the raw material mixture in paragraph 8.

13. In the 8th paragraph, the aliphatic diol is 1,4-butanediol, 1,2-butanediol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl, 1,3-propanediol, cyclic aliphatic diols, or a combination thereof. A method for producing a biodegradable polyester resin composition.

14. A method for producing a biodegradable polyester resin composition, wherein the aliphatic diol is contained in an amount of 30 mol% to 60 mol% based on the total molar number of the raw material mixture in the 8th paragraph.

15. A method for producing a biodegradable polyester resin composition in claim 8, wherein the molar ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid and the aliphatic diol is 1.0:0.8 to 1.0:1.

2.

16. A biodegradable polyester film obtained by melt-extruding the biodegradable polyester resin composition of any one of claims 1 to 7 using a blown film extruder.

17. A biodegradable polyester film obtained by melt-extruding a biodegradable polyester resin composition manufactured by the manufacturing method of any one of claims 8 to 15 using a blown film extruder.

Images