Biodegradable polyester polymerization composition, biodegradable polyester resin using the same, and method for producing the same

Abstract

The present embodiment relates to a biodegradable polyester polymerization composition, a biodegradable polyester resin using the same, and a method for producing the same. The biodegradable polyester polymerization composition contains an inorganic filler in a specific content and satisfies a viscosity in a specific range, thereby being excellent in dispersibility during the polycondensation process, and the content and dispersion index of metal in the biodegradable polyester resin produced from the biodegradable polyester polymerization composition can be adjusted to an optimal range.

Description

[Technical field]

[0001] The embodiment relates to a biodegradable polyester polymer composition, a biodegradable polyester resin using the same, and a method for producing the same. [Background technology]

[0002] In recent years, as concerns about environmental issues have grown, solutions are being sought for the disposal of various daily necessities, especially disposable products. Specifically, commonly used polymeric materials have the disadvantages that they emit harmful substances when incinerated and that, depending on the type, they can take hundreds of years to completely decompose naturally.

[0003] In order to overcome the limitations of such polymers, active research is being conducted on biodegradable polymers that decompose within a shorter time period. Examples of biodegradable polymers that have been used include polybutyleneadipate terephthalate (PBAT), polybutylenesuccinate (PBS), polybutyleneadipate (PBA), and polycaprolactone (PCL).

[0004] However, since the biodegradable polymer has a viscosity more than twice as high as that of polyethylene terephthalate (PET), when additives such as inorganic fillers are compounded (blended) with the biodegradable polymer resin, hydrolysis or thermal decomposition may occur during the compounding process, causing a rapid decrease in molecular weight, resulting in a problem of deterioration in mechanical properties.

[0005] In addition, when manufacturing films or molded articles using the biodegradable polymer, since additives such as the inorganic filler tend to aggregate, defects such as voids may occur during blow molding or extrusion stretching. Such defects can cause scratches on the film or molded article, or the aggregated particles may make the surface roughness uneven, resulting in excessive light scattering and a reduction in transparency. There are also problems such as the precipitation of the inorganic filler outside the biodegradable polymer resin or film, or the generation of internal defects in the film or molded article.

[0006] On the other hand, Patent Document 1 discloses a method for manufacturing a film by blending additives such as an inorganic filler or a plasticizer with polylactic acid and an aliphatic-aromatic copolyester. However, since the transparency of the final film is extremely low or the oxygen permeability is high, there is a problem that it is difficult to use for packaging applications that require high transparency and low oxygen permeability.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The implementation example was devised to solve the problems of the aforementioned prior art.

[0009] The implementation example aims to provide a biodegradable polyester polymerization composition capable of improving dispersibility during the polymerization (condensation polymerization) process.

[0010] Another implementation example aims to provide a biodegradable polyester resin that can improve tensile strength and transparency, reduce oxygen permeability, and provide excellent oxygen barrier properties, so that it can be widely used for packaging.

[0011] Another embodiment is to provide a method for producing the biodegradable polyester resin that can prevent filter clogging during melt extrusion, minimize void generation during the processing, improve processability, productivity, and moldability, and realize the above characteristics in an economical and efficient manner.

[0012] Another embodiment is to provide a biodegradable polyester film and an environmentally friendly packaging material that are biodegradable, environmentally friendly, and excellent in mechanical strength, transparency, and oxygen barrier properties by using the biodegradable polyester polymerization composition or the biodegradable polyester resin having the above excellent characteristics. **Means for Solving the Problems**

[0013] One embodiment is a biodegradable polyester polymerization composition comprising an aliphatic polyester polymerization composition or an aliphatic-aromatic polyester polymerization composition and an inorganic filler, wherein the aliphatic polyester polymerization composition is selected from the group consisting of lactide monomers and their ring-opening prepolymers, and the aliphatic-aromatic polyester polymerization composition is selected from the group consisting of a monomer composition containing a diol component and a dicarboxylic acid component and a prepolymer of a part or all of the monomer composition, and the inorganic filler is contained in an amount of 0.1% by weight to 10% by weight based on the total weight of the biodegradable polyester polymerization composition, and the biodegradable polyester polymerization composition has a viscosity of 5,000 to 15,000 poises at 240°C, to provide a biodegradable polyester polymerization composition.

[0014] Another embodiment is a biodegradable polyester resin formed from the biodegradable polyester polymerization composition, wherein the content of metal in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the total weight, and the dispersion index (DI) represented by the following formula 1 is 3.0 or more, to provide a biodegradable polyester resin.

[0015] [Formula 1] JPEG2025522301000001.jpg1570In the formula 1 above, TS and OP are values excluding the units measured on the biodegradable polyester sheet specimens made of the biodegradable polyester resin, wherein the TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing specimens according to ASTM D638 Type V standard, the OP is the oxygen permeability (CC / m 2 ·day·atm) measured at a temperature of 25 °C and a relative humidity (RH) of 0% using OX-TRAN 702 after preparing specimens with a thickness of 500 μm according to ASTM D3985.

[0016] Another embodiment includes the step of subjecting the biodegradable polyester polymerization composition to a polycondensation reaction at least once, wherein the metal content in the biodegradable polyester resin is 0.01 wt% to 7 wt% based on the total weight, and the dispersion index (DI) represented by the formula 1 is 3.0 or more, and provides a method for producing a biodegradable polyester resin.

[0017] Another embodiment includes the biodegradable polyester resin, wherein the biodegradable polyester resin is a biodegradable polyester resin formed from the biodegradable polyester polymerization composition, the metal content in the biodegradable polyester resin is 0.01 wt% to 7 wt% based on the total weight, and the dispersion index (DI) represented by the formula 1 is 3.0 or more, and provides a biodegradable polyester film.

Advantages of the Invention

[0018] The biodegradable polyester polymerization composition according to the embodiment contains an inorganic filler in a specific content and satisfies a viscosity in a specific range, so that it has excellent dispersibility in the polymerization (polycondensation) process, and the metal content and dispersion index in the biodegradable polyester resin produced from the biodegradable polyester polymerization composition can be adjusted to an optimal range.

[0019] In addition, the biodegradable polyester resin in which the metal content and the dispersion index in the biodegradable polyester resin are adjusted to an optimal range can improve transparency and tensile strength, reduce the static friction coefficient and the oxygen permeability, and provide a biodegradable film excellent in characteristics for packaging.

[0020] Furthermore, the method for producing a biodegradable polyester resin according to the implementation example is to carry out a polycondensation reaction using the biodegradable polyester polymerization composition containing the inorganic filler. As a result, the dispersibility during the polycondensation reaction is very excellent, and the aggregation of the inorganic filler particles can be suppressed. Therefore, the filter clogging phenomenon can be prevented, the occurrence of defects such as voids in the processing step can be reduced, and the moldability, processability, and productivity can be improved simultaneously, and a biodegradable film and a molded product of excellent quality can be provided.

Mode for Carrying Out the Invention

[0021] Hereinafter, the invention will be described in detail by way of implementation examples. The implementation examples are not limited to the content disclosed below, and can be deformed into various forms unless the gist of the invention is changed.

[0022] In this specification, when a certain part says that a certain component "includes", this means that, unless otherwise stated, it does not exclude other components, but may further include other components.

[0023] Also, all numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification should be understood to be modified by the term "about" in all cases unless otherwise stated.

[0024] In this specification, terms such as first, second, primary, secondary, etc. are used to explain various components, and the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0025] In one implementation example, by subjecting the biodegradable polyester polymerization composition containing an inorganic filler in a specific content to polycondensation to produce a biodegradable polyester resin, the content and dispersion index (DI) of the metal in the biodegradable polyester resin can be satisfied within a specific range. As a result, transparency can be further improved, the generation of voids in the processing step can be reduced, the oxygen permeability can be reduced while improving the tensile strength, and the oxygen barrier property can be improved, so that it can be variously utilized as a packaging material. Furthermore, since excellent dispersibility can be achieved without using a dispersing agent, there is a technical significance in that a high-quality environmentally friendly packaging material that is biodegradable and can exhibit excellent properties can be realized by an economical and efficient method.

[0026] [Biodegradable polyester polymerization composition] The biodegradable polyester polymerization composition according to one implementation example includes an aliphatic polyester polymerization composition or an aliphatic-aromatic polyester polymerization composition and an inorganic filler. The aliphatic polyester polymerization composition is selected from one or more of the group consisting of lactide monomers and their ring-opening prepolymers. The aliphatic-aromatic polyester polymerization composition is selected from one or more of the group consisting of a monomer composition containing a diol component and a dicarboxylic acid component and a prepolymer of part or all of the monomer composition. The inorganic filler is included at 0.1% by weight to 10% by weight based on the total weight of the biodegradable polyester polymerization composition, and the biodegradable polyester polymerization composition has a viscosity of 5000 to 15000 poises at 240°C.

[0027] Specifically, the biodegradable polyester polymerization composition may include an aliphatic polyester polymerization composition or an aliphatic-aromatic polyester polymerization composition.

[0028] The aliphatic polyester polymerization composition may be selected from one or more of the group consisting of lactide monomers and their ring-opening prepolymers.

[0029] The lactide monomer may include L-lactide, D-lactide, or a combination thereof.

[0030] The aliphatic-aromatic polyester polymerization composition may be selected from the group consisting of a monomer composition containing a diol component and a dicarboxylic acid component, and a prepolymer of part or all of the monomer composition.

[0031] For example, the aliphatic-aromatic polyester polymerization composition may include a prepolymer obtained by subjecting a mixture containing a slurry obtained by mixing a diol component and an aromatic dicarboxylic acid component and an aliphatic dicarboxylic acid component, or a mixture containing a reaction product obtained by subjecting the slurry to an esterification reaction and an aliphatic dicarboxylic acid component, to an esterification reaction at least once.

[0032] The diol component may include 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or a derivative thereof.

[0033] The aromatic dicarboxylic acid component may include terephthalic acid, dimethyl terephthalate, or a derivative thereof.

[0034] The aliphatic dicarboxylic acid component may include adipic acid, succinic acid, sebacic acid, or a derivative thereof.

[0035] On the other hand, the biodegradable polyester polymerization composition may contain an inorganic filler in an amount of 0.1% by weight to 10% by weight based on the total weight of the biodegradable polyester polymerization composition.

[0036] Generally, inorganic fillers are used for the purpose of improving slip properties during processing. However, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene adipate (PBA), polycaprolactone (PCL), etc., which are widely used as biodegradable polymers, have a high viscosity with a number average molecular weight of at least 40,000. Therefore, when an inorganic filler is added during the polymerization process, the reaction may be delayed or may not proceed.

[0037] On the one hand, when compounding (blending) an inorganic filler and a biodegradable polyester resin, not only a large amount of inorganic filler is required to achieve the above effects, but also the compatibility between the biodegradable polyester resin and the inorganic filler is poor. Therefore, during the blowing process and / or during extrusion stretching, voids may occur, causing bubbles to burst or breakage to occur, resulting in a decrease in productivity and problems acting as internal and surface defects of the film.

[0038] Therefore, according to an embodiment of the present invention, in order to achieve optimal dispersibility and efficiently achieve the desired effects, the content of the inorganic filler is adjusted, and the specific surface area and particle size range of the inorganic filler, the pretreatment process, and the addition timing are controlled, etc., to solve the above problems, improve the dispersibility during the polymerization process, and control the metal content and dispersion index in the biodegradable polyester resin produced from the biodegradable polyester polymerization composition within an optimal range. Thereby, the surface roughness, haze, coefficient of static friction, oxygen permeability, and tensile strength of the biodegradable polyester sheet or film can be improved overall.

[0039] Specifically, the biodegradable polyester polymerization composition may contain the inorganic filler, based on the total weight of the biodegradable polyester polymerization composition, for example, 0.1 wt% - 10 wt%, 0.5 wt% - 9 wt%, 1 wt% - 9 wt%, 1 wt% - 8 wt%, 1 wt% - 6 wt%, 1 wt% - 5 wt%, 2 wt% - 5 wt%, 3 wt% - 5 wt%, or 4 wt% - 6 wt%.

[0040] When the content of the inorganic filler satisfies the above range, agglomeration of the inorganic filler can be minimized, the occurrence of defects such as voids can be reduced, and the dispersibility can be improved. Therefore, it can be more advantageous for achieving the effects aimed at in the present invention, that is, improving transparency and tensile strength and reducing surface roughness, coefficient of static friction, and oxygen permeability.

[0041] If the content of the inorganic filler is less than the above range, it is difficult to achieve the effects targeted by the present invention. If it exceeds the above range, surface roughness and haze increase, oxygen permeability increases, and tensile strength decreases, which may cause various problems when used as a packaging material.

[0042] The inorganic filler may include one or more selected from the group consisting of SiO2, CaCO3, TiO2, BaSO4, and Al2O3. Specifically, the inorganic filler may include one or more selected from the group consisting of SiO2, CaCO3, and TiO2. Inclusion of the inorganic filler may be further advantageous for improving slipperiness during processing.

[0043] On the other hand, according to one implementation example of the present invention, the specific surface area and average particle size of the inorganic filler can be controlled within a specific range, which may be further advantageous for improving dispersibility during the polymerization process and improving the mechanical strength of the biodegradable polyester sheet, film, or molded article.

[0044] The inorganic filler has a specific surface area (by the BET (Brunauer - Emmett - Teller) method) of, for example, 1000 m 2 / g or less, 900 m 2 / g or less, 800 m 2 / g or less, 600 m 2 / g or less, 500 m 2 / g or less, 400 m 2 / g or less, 300 m 2 / g or less, or 250 m 2 / g or less, and 20 m 2 / g or more, 30 m 2 / g or more, 40 m 2 / g or more, 50 m 2 / g or more, 50 m 2 / g or more, 55 m 2 / g or more, 60 m 2 / g or more, 70 m 2 / g or more, 80 m 2 / g or more, or 100 m 2It can be / g or more. The specific surface area can be measured using, for example, a BET specific surface area analyzer (ASAP 2020, manufactured by Micromeritics).

[0045] When the specific surface area of the inorganic filler satisfies the above range, aggregation of the particles of the inorganic filler can be prevented, which is advantageous for adjusting the metal content and the dispersion index in the biodegradable polyester resin targeted in the present invention to an optimal range, and can further improve the surface roughness and mechanical strength of the biodegradable polyester sheet. If the specific surface area of the inorganic filler exceeds the above range, the particles of the inorganic filler are likely to aggregate as secondary particles and are likely to lose stability and re-aggregate even if dispersed.

[0046] Further, the inorganic filler may have an average particle size (D50) of, for example, 15 μm or less, 13 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, 5 μm or less, 4 μm or less, or 3 μm or less. Further, the inorganic filler may have an average particle size (D50) of, for example, 0.1 μm or more, 0.3 μm or more, 0.5 μm or more, 0.6 μm or more, 0.7 μm or more, 0.8 μm or more, or 1 μm or more. The average particle size (D50) of the inorganic filler means the particle size or the median diameter when the cumulative volume becomes 50%, and can be measured using a particle size analyzer Microtrac S3500 with a particle size distribution (PSD). When the average particle size (D50) of the inorganic filler satisfies the above range, aggregation of the particles of the inorganic filler can be prevented, which is advantageous for adjusting the metal content and the dispersion index in the biodegradable polyester resin targeted in the present invention to an optimal range, and can further improve the surface roughness and mechanical strength of the biodegradable polyester sheet.

[0047] Note that the inorganic filler can be an inorganic filler pretreated by one or more methods selected from ultrasonic treatment, a mixer tank, a high-pressure homogenizer (homogenizer), and pretreatment with a dispersant.

[0048] When the inorganic filler is pretreated by the above method, dispersion can be made easier in the polycondensation stage. In particular, since aggregation does not occur even during the transfer of each reactor, the phenomenon of filter clogging can be prevented, and there is an advantage that excellent dispersibility can be realized without adding a dispersant.

[0049] Specifically, the ultrasonic treatment is a method of physically crushing or pulverizing the particles of the inorganic filler by waves generated by emitting ultrasonic waves of 20 kHz into a solution.

[0050] The ultrasonic treatment can be performed in a time of less than 30 minutes with an energy amount of 50000 J or less. For example, the ultrasonic treatment can be performed with an energy amount of 25000 J or less or 22000 J or less in a time of 25 minutes or less, 20 minutes or less, or 18 minutes or less. By satisfying the above ranges for the energy amount and the implementation time, the effect of the ultrasonic treatment, that is, the improvement of dispersibility, can be maximized. If the energy amount exceeds the above range, rather, the particles of the inorganic filler may re-aggregate and the dispersibility may decrease. Further, when the particles of the inorganic filler aggregate or re-aggregate, the surface roughness of the biodegradable polyester sheet or film produced from the biodegradable polyester polymerization composition becomes non-uniform, and when light is transmitted, a lot of scattering is caused and the transparency may be reduced.

[0051] The pretreatment by the mixer tank can be carried out by using a slurry tank with a dust explosion-proof equipment specification and stirring the inorganic filler at a temperature of about 2000 rpm or less, for example, 200 to 2000 rpm, 300 to 2000 rpm, 500 to 2000 rpm, 200 to 1000 rpm, 250 to 1000 rpm, or 300 to 1000 rpm for 1 hour or more.

[0052] The pretreatment by the high-pressure homogenizer involves passing high-pressure fluid through small gaps in an interaction chamber at high speed. At this time, a supersonic flow rate is formed due to a sharp drop in pressure, and impact, cavitation, turbulent flow, and shear forces act on the particles in the fluid, and it can be a mechanical pretreatment method in which the inorganic filler is broken into uniform fine particles to make it in a homogeneous state. The pretreatment method by the high-pressure homogenizer can be carried out under pressure conditions of 5000 - 40000 psi.

[0053] The pretreatment by the dispersant can be carried out by dispersing the inorganic filler in the dispersant. The dispersant may include one or more selected from the group consisting of acidity regulators, surface modifiers, and emulsifiers in polymer or monomer form. For example, it may include one or more selected from the group consisting of siloxane-based polyols, stearic acid-based fatty acids, and surfactants.

[0054] Also, when adding the inorganic filler, an additional diol component (third diol component) can be added in combination to improve dispersibility and reactivity.

[0055] According to an embodiment of the present invention, when polycondensation is carried out using the biodegradable polyester polymerization composition containing the inorganic filler to produce a biodegradable polyester resin, compared with the case of compounding (blending) the polyester resin and the inorganic filler, the dispersibility can be further improved, void formation can be reduced, the bubble stability during processing can be improved, the elongation rate and tensile strength can be improved, and the filter clogging phenomenon can be minimized, so the productivity, processability, and moldability can be further improved.

[0056] The viscosity of the biodegradable polyester polymerization composition can be, for example, 5000 poises or more, 6000 poises or more, 6500 poises or more, 7000 poises or more, or 8000 poises or more at 240°C. Also, the viscosity of the biodegradable polyester polymerization composition can be, for example, 15000 poises or less, 13000 poises or less, 12000 poises or less, 11000 poises or less, or 10000 poises or less. Specifically, the viscosity of the biodegradable polyester polymerization composition can be, for example, 6000 - 13000 poises, 7000 - 13000 poises, 6000 - 12000 poises, 6000 - 11000 poises, or 6000 - 10000 poises.

[0057] When the viscosity of the biodegradable polyester polymerization composition satisfies the above range, the dispersibility during the polycondensation reaction is further improved. Needless to say, the mechanical strength of the biodegradable resin is improved, and the surface roughness, haze, coefficient of static friction, and oxygen permeability of the biodegradable polyester sheet or film can be reduced, which can be further advantageous for realizing composite physical property values such as the dispersion index (DI) and the processability reduction index (PRI) at an optimal level. The viscosity is the viscosity of the biodegradable polyester polymerization composition measured immediately after adding the inorganic filler, and is measured using a dynamic viscometer, the RDS (Rheometrics Dynamic Spectrometer, Discovery HR30, TA Instrument), at a temperature of 240°C while increasing the angular velocity per second (1 rad / sec) (1 rad / sec is 9.5 rpm). The viscosity can vary depending on the shear rate.

[0058] On the other hand, according to an implementation example, the present invention can provide a biodegradable polyester masterbatch using the biodegradable polyester polymerization composition.

[0059] The biodegradable polyester masterbatch can be produced by a normal method using the biodegradable polyester polymerization composition.

[0060] By using the biodegradable polyester masterbatch and performing in-situ polymerization, the dispersibility can be further improved, the occurrence of defects such as voids in the processing step can be reduced, the tensile strength can be further increased, the oxygen permeability can be decreased, and a biodegradable film with excellent properties for packaging can be provided.

[0061] [Biodegradable polyester resin] The biodegradable polyester resin according to one implementation example is a biodegradable polyester resin formed by the biodegradable polyester polymerization composition, wherein the metal content in the biodegradable polyester resin is 0.01 wt% to 7 wt% based on the total weight, and the dispersion index (DI) represented by the following formula 1 is 3.0 or more.

[0062] [Formula 1] In the formula 1, TS and OP are numerical values excluding the units measured on a biodegradable polyester sheet test piece manufactured by the biodegradable polyester resin, The TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing a test piece according to ASTM D638 Type V standard, The OP is the oxygen permeability (CC / m 2 ·day·atm) measured at a temperature of 25°C and a relative humidity (RH) of 0% using OX-TRAN 702 after preparing a 500-μm-thick test piece in accordance with ASTM D3985.

[0063] By using the biodegradable polyester polymerization composition, the metal content in the biodegradable polyester resin can be satisfied within a specific range, thereby overall improving the physical properties of the surface roughness, haze, coefficient of static friction, oxygen permeability, and tensile strength of the biodegradable polyester sheet or film, and realizing composite physical property values such as the dispersion index (DI) and the processability reduction index (PRI) at an optimal level.

[0064] For example, the content of the metal in the biodegradable polyester resin may be 0.015% by weight or more, 0.02% by weight or more, 0.03% by weight or more, 0.05% by weight or more, more than 0.05% by weight, 0.07% by weight or more, 0.09% by weight or more, or 0.1% by weight or more, and may be 7% by weight or less, 6% by weight or less, or 5% by weight or less, based on the total weight of the biodegradable polyester polymerization composition. Also, the content of the metal in the biodegradable polyester resin may be, for example, 0.015% by weight to 6.8% by weight, more than 0.015% by weight to 6.8% by weight or less, 0.02% by weight to 6.8% by weight, 0.03% by weight to 6.8% by weight, 0.05% by weight to 6.8% by weight, 0.06% by weight to 6.8% by weight, 0.06% by weight to 6.5% by weight, 0.06% by weight to 6% by weight, 0.06% by weight to 5% by weight, 0.1% by weight to 4% by weight, or 0.1% by weight to 3% by weight, based on the total weight of the biodegradable polyester polymerization composition.

[0065] The content of the metal in the biodegradable polyester resin may vary depending on the content of the inorganic filler contained in the biodegradable polyester polymerization composition.

[0066] When the content of the metal in the biodegradable polyester resin satisfies the above range, it may be further advantageous for improving the transparency and tensile strength of the biodegradable polyester sheet or film produced from the biodegradable polyester resin, and for reducing the surface roughness, static friction coefficient, and oxygen permeability.

[0067] When the content of the metal in the biodegradable polyester resin is less than the above range, there is a problem of reduced processing slip property, and when the content of the metal exceeds the above range, there may be problems such as re-aggregation and the appearance of protrusions.

[0068] The metal contained in the biodegradable polyester resin may include one or more selected from the group consisting of Si, Ca, Ti, Ba, and Al. Specifically, the metal contained in the biodegradable polyester resin may include one or more selected from the group consisting of Si, Ca, and Ti. Inclusion of the metal may be further advantageous for improving the slip property during processing.

[0069] On the one hand, the content of residual inorganic substances contained in the biodegradable polyester resin can be 0.02% to 8% by weight. Specifically, the content of residual inorganic substances contained in the biodegradable polyester resin can be 0.02% to 7% by weight, 0.1% to 6.5% by weight, 0.2% to 6.5% by weight, 0.2% to 6% by weight, or 0.5% to 5% by weight.

[0070] The residual inorganic substances are residues of inorganic fillers contained in the biodegradable polyester resin, and may include, for example, one or more selected from the group consisting of SiO2, CaCO3, TiO2, BaSO4, and Al2O3.

[0071] In addition, the biodegradable polyester resin may have a dispersion index (DI) represented by the formula 1 of 3.0 or more.

[0072] The dispersion index (DI) is represented by the ratio of the tensile strength of the biodegradable polyester sheet to the oxygen permeability (OP) of the biodegradable polyester sheet produced from the biodegradable polyester resin. This indicates whether the particles of the inorganic filler are appropriately dispersed during the polymerization process during the production of the biodegradable resin, and at the same time, can indicate the degree of dispersion of the metal and / or residual inorganic particles present in the biodegradable polyester resin formed from the inorganic filler. Also, thereby, the oxygen permeability (OP) and tensile strength of the biodegradable polyester sheet or film produced from the biodegradable polyester resin can change.

[0073] For example, the lower the oxygen permeability (OP) of the biodegradable polyester sheet produced from the biodegradable polyester resin, the higher the dispersion index (DI), and the higher the tensile strength of the biodegradable polyester sheet, the higher the dispersion index (DI).

[0074] That is, the fact that the oxygen permeability (OP) of the biodegradable polyester sheet is low or the tensile strength of the biodegradable polyester sheet is high means that during the production of the biodegradable resin, the particles of the inorganic filler were appropriately dispersed during the polymerization process, and it may mean that the dispersion of the metal and / or residual inorganic particles present in the biodegradable polyester resin was made uniform.

[0075] The dispersion index (DI) can be, for example, 3.2 or more, 3.5 or more, 4.0 or more, 4.2 or more, 4.3 or more, 4.5 or more, 4.6 or more, or 5.0 or more. Also, the dispersion index (DI) can be, for example, 15.0 or less, 12.0 or less, 11.0 or less, 10.0 or less, 9.5 or less, 9.0 or less, or 8.0 or less.

[0076] When the dispersion index (DI) satisfies the above range, the oxygen permeability (OP) of the biodegradable polyester sheet produced from the biodegradable polyester resin can be lowered, and the tensile strength can be further improved.

[0077] According to one embodiment of the present invention, the oxygen permeability (OP) of the biodegradable polyester sheet produced from the biodegradable polyester resin is, for example, 800 CC / m 2 ·day·atm or less, 10 - 800 CC / m 2 ·day·atm, 20 - 800 CC / m 2 ·day·atm, 30 - 780 CC / m 2 ·day·atm, 30 - 770 CC / m 2 ·day·atm, 30 - 750 CC / m 2 ·day·atm, 30 - 700 CC / m 2 ·day·atm, or 30 - 650 CC / m 2 ·day·atm.

[0078] When the oxygen permeability (OP) of the biodegradable polyester sheet satisfies the above range, it has excellent oxygen barrier properties and may be more advantageous for use as a packaging material, particularly a food packaging material. If the oxygen permeability (OP) of the biodegradable polyester sheet is 800 CC / m2 ·When it exceeds ·day·atm, the oxygen barrier property is poor, and various problems may occur when used as a packaging material.

[0079] According to one embodiment of the present invention, the tensile strength (TS) of the biodegradable polyester sheet made of the biodegradable polyester resin can be, for example, 35 Mpa or more, 35 Mpa to 100 Mpa, 35 Mpa to 90 Mpa, 35 Mpa to 80 Mpa, 35 Mpa to 60 Mpa, 37 Mpa to 55 Mpa, or 38 Mpa to 50 Mpa.

[0080] When the tensile strength (TS) satisfies the above range, it is more advantageous to realize the dispersion index (DI) in the specific range, and since the range of the tensile strength is appropriate, the durability of the packaging material can be further improved.

[0081] On the other hand, the biodegradable polyester resin may have a processability reduction index (PRI) represented by the following formula 2 of 100 or less.

[0082] [Formula 2] Processability reduction index (PRI) = Ra + Hz In the above formula 2, Ra and Hz are numerical values excluding the units measured on a biodegradable polyester sheet test piece made of the biodegradable polyester resin, The Ra is the center line average roughness (Ra) (nm) calculated by measuring the two-dimensional surface roughness at five or more locations on the surface of the test piece after preparing the test piece by cutting it to a length of 3 cm and a width of 3 cm according to the JIS B0601 standard and using a surface roughness meter, The Hz is the haze (%) measured using a haze meter after preparing the test piece by cutting it to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to the ASTM D1003 standard.

[0083] The processability reduction index (PRI) of the biodegradable polyester resin is indicated by the sum of the center line average roughness (Ra) and haze of the biodegradable polyester sheet produced from the biodegradable polyester resin. That is, the center line average roughness (Ra) and haze (Hz) of the biodegradable polyester sheet vary depending on the degree of aggregation of the inorganic filler particles in the biodegradable polyester resin, and thus can have a great influence on processability. Further, when there is aggregation of the inorganic filler particles, the surface roughness of the biodegradable polyester sheet or film becomes non-uniform, causing a lot of scattering when light passes through, reducing the transparency of the biodegradable polyester sheet or film, and there may be problems such as precipitation of the inorganic filler particles or remaining as internal defects.

[0084] The processability reduction index (PRI) of the biodegradable polyester resin may decrease as the center line average roughness (Ra) of the biodegradable polyester sheet decreases, or may decrease as the haze (Hz) decreases. Also, the lower the value of the processability reduction index (PRI) of the biodegradable polyester resin, the more advantageous it may be for providing a biodegradable film with excellent characteristics for packaging.

[0085] The processability reduction index (PRI) of the biodegradable polyester resin may be, for example, 100 or less, 99 or less, 98 or less, 97 or less, 95 or less, 90 or less, 85 or less, 82 or less, 80 or less, or 78 or less. Specifically, the processability reduction index (PRI) of the biodegradable polyester resin may be, for example, 30 to 100. When the processability reduction index (PRI) of the biodegradable polyester resin satisfies the above range, it is more advantageous in the processing step, has excellent slipperiness, can further reduce the occurrence of defects inside or on the surface of the biodegradable film, and may be advantageous for providing a high-quality packaging material.

[0086] The center line average roughness (Ra) of the biodegradable polyester sheet made of the biodegradable polyester resin can be calculated by cutting a test piece to a length of 3 cm and a width of 3 cm according to the JIS B0601 standard, and then measuring the two-dimensional surface roughness at five or more points on the surface of the test piece using a surface roughness meter. This can be measured with an AFM device (for example, XE-150, Park System). For example, the center line average roughness (Ra) is the arithmetic average roughness of the deviation of the roughness curve with respect to the average line according to JIS 0161, which is obtained by summing the entire upper and lower sides from the center line of the reference length and dividing the value by the length of the measurement section.

[0087] The center line average roughness (Ra) of the biodegradable polyester sheet is, for example, 50 nm or less, 48 nm or less, 47 nm or less, 46 nm or less, 45 nm or less, 42 nm or less, 40 nm or less, or 39 nm or less, and specifically can be 10 nm to 50 nm.

[0088] When the center line average roughness (Ra) of the biodegradable polyester sheet satisfies the above range, it may be more advantageous for achieving the effects intended in the present invention. If the center line average roughness (Ra) of the biodegradable polyester sheet exceeds 50 nm, the surface roughness becomes non-uniform, which may cause a lot of scattering when light passes through, thereby reducing the transparency of the biodegradable polyester sheet or film.

[0089] According to another embodiment of the present invention, the haze of the biodegradable polyester sheet made of the biodegradable polyester resin is as low as 50% or less, which has the advantage of excellent transparency and can be widely used in applications that require transparency.

[0090] Specifically, the haze of the biodegradable film can be 48% or less, 45% or less, 43% or less, or 40% or less. If the haze exceeds the above range, the transparency may be insufficient and its applications may be limited.

[0091] On the other hand, according to another embodiment of the present invention, the static friction coefficient of the biodegradable polyester sheet made of the biodegradable polyester resin is 5 or less, for example, 4.5 or less, 4 or less, 3.5 or less, 3.2 or less, 3 or less, 2.8 or less, 2.5 or less, 2.2 or less, or 2.1 or less. The static friction coefficient of the biodegradable polyester sheet can be measured by bringing one surface of stainless steel (SUS) into contact with and sliding on the biodegradable polyester sheet in accordance with ASTM D1894 using a friction coefficient tester (QM110CF, QMESYS).

[0092] On the other hand, the intrinsic viscosity of the biodegradable polyester resin may be similar to or the same as the viscosity of the above-described biodegradable polyester polymerization composition at 240°C. For example, the intrinsic viscosity of the biodegradable polyester resin may be 5000 poises or more, 6000 poises or more, 6500 poises or more, 7000 poises or more, or 8000 poises or more, and may be 15000 poises or less, 13000 poises or less, 12000 poises or less, 11000 poises or less, or 10000 poises or less. Also, the intrinsic viscosity of the biodegradable polyester resin may be 6000 poises to 13000 poises, 7000 poises to 13000 poises, 6000 poises to 12000 poises, 6000 poises to 11000 poises, or 6000 poises to 10000 poises. The viscosity is measured using a dynamic viscometer (Discovery HR30, TA Instrument) at a temperature of 240°C while increasing the angular velocity per second (1 rad / sec) (1 rad / sec is 9.5 rpm), and is the viscosity measured immediately after polymerization.

[0093] When the viscosity of the biodegradable polyester resin satisfies the above range, the occurrence of defects such as voids in the processing step can be reduced, and the processability, productivity, and moldability can be further improved. Of course, excellent mechanical properties can be obtained, and the oxygen permeability can be reduced to provide a biodegradable film having excellent properties for packaging.

[0094] Also, the number average molecular weight of the biodegradable polyester resin can be 30,000 g / mol to 100,000 g / mol. It can be 40,000 g / mol to 90,000 g / mol, or 40,000 g / mol to 80,000 g / mol. The number average molecular weight can be measured using gel permeation chromatography (GPC). Specifically, the data obtained by gel permeation chromatography includes various items such as Mn, Mw, and Mp. Among them, the molecular weight can be measured based on the number average molecular weight (Mn). By satisfying the above range of the number average molecular weight of the polymer, the strength and processability can be further improved.

[0095] On the other hand, when the filter pressure is measured with an extruder equipped with a single screw and a 40 μm mat filter for the biodegradable polyester resin, the difference in filter pressure (ΔFP) represented by the following formula 3 is 100 kg / cm 2 can be as follows.

[0096] [Formula 3] ΔFP = │FP0 - FP2│ In the above formula 3, FP0 is the initial pressure (kg / cm 2 ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C, FP2 is the pressure (kg / cm 2 ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C for 2 hours.

[0097] The difference in filter pressure (ΔFP) is the absolute value of the difference between the initial pressure (kg / cm 2 ) applied to the filter when extruded at 240 °C and the pressure (kg / cm 2 ) applied to the filter when extruded at the same temperature for 2 hours, and means the change amount of the filter pressure.

[0098] During the polycondensation reaction of the biodegradable polyester resin, when the dispersion of the inorganic filler particles is good, the difference in filter pressure (ΔFP) is small. When the dispersion of the inorganic filler particles does not go well and aggregation occurs, the filter may become clogged, causing an increase in filter pressure or the possibility of the filter bursting, which can cause problems in productivity, processability, and moldability. Therefore, it is very important to control the difference in filter pressure (ΔFP) below a specific range.

[0099] For example, the difference in filter pressure (ΔFP) is 90 kg / cm 2 or less, 85 kg / cm 2 or less, 80 kg / cm 2 or less, 70 kg / cm 2 or less, 60 kg / cm 2 or less, 50 kg / cm 2 or less, 40 kg / cm 2 or less, 30 kg / cm 2 or less, or 20 kg / cm 2 or less, and within the above range, the smaller the difference in filter pressure (ΔFP), the more advantageous it may be in terms of productivity, processability, and moldability.

[0100] On the other hand, the biodegradable polyester resin includes an aliphatic polyester resin or an aliphatic-aromatic polyester resin. The aliphatic polyester resin includes polylactic acid (PLA), and the aliphatic-aromatic polyester resin may include a first repeating unit containing a first diol residue and an aromatic dicarboxylic acid residue, and a second repeating unit containing a second diol residue and an aliphatic dicarboxylic acid residue.

[0101] The polylactic acid resin may include L-lactic acid, D-lactic acid, D,L-lactic acid, or a combination thereof.

[0102] Specifically, the polylactic acid resin may be a random copolymer of L-lactic acid and D-lactic acid. At this time, the content of the D-lactic acid may be, for example, 1 wt% to 5 wt%, 1 wt% to 4 wt%, 2 wt% to 4 wt%, 1 wt% to 2 wt%, or 2 wt% to 3 wt% based on the total weight of the polylactic acid resin. When the content of the D-lactic acid satisfies the above range, it may be advantageous in terms of improving the draw processability of the film.

[0103] The content of the L-lactic acid may be, for example, 80 wt% to 99 wt%, 83 wt% to 99 wt%, 85 wt% to 99 wt%, 95 wt% to 99 wt%, 96 wt% to 99 wt%, 96 wt% to 98 wt%, or 96 wt% to 97 wt% based on the total weight of the polylactic acid resin. When the content of the L-lactic acid satisfies the above range, it may be advantageous in terms of improving the heat resistance characteristics of the film.

[0104] The polylactic acid resin may have a melting temperature (Tm) of 100°C to 250°C, 110°C to 220°C, or 120°C to 200°C.

[0105] The polylactic acid resin may have a glass transition temperature (Tg) of 30°C to 80°C, 40°C to 80°C, 40°C to 70°C, or 45°C to 65°C.

[0106] The polylactic acid resin has a melt viscosity (V PLA ) at 210°C of, for example, 5000 poise to 12000 poise, 6500 poise to 12000 poise, 6500 poise to 11000 poise, 7000 poise to 12000 poise, 7500 poise to 11000 poise, or 8000 poise to 10000 poise. The melt viscosity can be measured using a rheometer (RDS).

[0107] The biodegradable polyester resin according to one implementation example of the present invention may include a first repeating unit containing a first diol residue and an aromatic dicarboxylic acid residue, and a second repeating unit containing a second diol residue and an aliphatic dicarboxylic acid residue.

[0108] The first and second diol residues each independently contain residues of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or derivatives thereof, the aromatic dicarboxylic acid residue contains residues of terephthalic acid, dimethyl terephthalate, or derivatives thereof, and the aliphatic dicarboxylic acid residue contains residues of adipic acid, succinic acid, sebacic acid, or derivatives thereof.

[0109] The biodegradable polyester resin having the above structure can improve the biodegradability, hydrolysis, and physical properties of the biodegradable polyester sheet, film, or molded article obtained using the same.

[0110] The number of the first repeating units can be 90 to 500, 90 to 400, 90 to 300, 90 to 200, 90 to 150, 90 to 140, 90 to 130, 90 to 120, 100 to 120, or 100 to 115.

[0111] The number of the second repeating units can be 50 to 500, 50 to 400, 50 to 300, 50 to 200, 50 to 150, 55 to 120, 60 to 150, 60 to 130, 60 to 120, 80 to 150, 90 to 150, 95 to 150, 96 to 150, 96 to 130, 96 to 120, or 98 to 120.

[0112] When the number of the first repeating units and the number of the second repeating units each satisfy the above ranges, the molecular weight of the desired biodegradable polyester resin can be realized, the processability and physical properties can be improved, and the mechanical properties, heat resistance, and biodegradability of the biodegradable polyester sheet, film, or molded article manufactured using the same can be further improved. If the number of the first repeating units and / or the number of the second repeating units is too small, the molecular weight of the biodegradable polyester resin will also be small, and it may be difficult to achieve the desired physical properties.

[0113] On the other hand, the biodegradable polyester resin may further contain nanocellulose having an average particle size of 100 nm or more.

[0114] The average particle size of the nanocellulose can be, for example, 100 nm to 500 nm, 100 nm to 450 nm, 120 nm to 400 nm, 130 nm to 350 nm, 140 nm to 300 nm, or 150 nm to 300 nm.

[0115] By satisfying the above range for the average particle size of the nanocellulose, the biodegradability and physical properties of the biodegradable polyester resin, or the biodegradable polyester sheet, film, and molded article obtained using the same can be further improved.

[0116] The nanocellulose can be one or more selected from the group consisting of cellulose nanocrystals, cellulose nanofibers, microfibrillated cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, pentyl cellulose, hexyl cellulose, and cyclohexyl cellulose.

[0117] Also, the nanocellulose can be pre-treated with a bead mill or ultrasonically pre-treated. Specifically, the nanocellulose can be one in which the water-dispersed nanocellulose is pre-treated with a bead mill or ultrasonically pre-treated.

[0118] First, the pre-treatment with the bead mill can be performed using a vertical mill or a horizontal mill as a wet milling device. The horizontal mill is preferable in that the amount of beads that can be filled inside the chamber is larger, the reduction of mechanical eccentric wear, the reduction of bead wear, and maintenance are easier, but it is not limited thereto.

[0119] The pre-treatment with the bead mill can be performed using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0120] Specifically, the bead mill pretreatment can be performed using beads having a diameter of 0.3 mm to 1 mm. For example, the diameter of the beads can be 0.3 mm to 0.9 mm, 0.4 mm to 0.8 mm, 0.45 mm to 0.7 mm, or 0.45 mm to 0.6 mm. By satisfying the above range of the bead diameter, the dispersibility of nanocellulose can be further improved. If the bead diameter exceeds the above range, the average particle size and particle size deviation of nanocellulose may increase and the dispersibility may decrease.

[0121] In addition, for the bead mill pretreatment, it is preferable to use beads having a higher specific gravity than that of nanocellulose in terms of being able to transmit sufficient energy. For example, the beads may be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide having a higher specific gravity than that of water-dispersed nanocellulose, and zirconium beads having a specific gravity 4 times or more higher than that of the water-dispersed nanocellulose are preferable, but not limited thereto.

[0122] The ultrasonic pretreatment is a method of physically crushing or pulverizing nanoparticles by waves generated by emitting ultrasonic waves of 20 kHz into a solution.

[0123] The ultrasonic pretreatment can be performed with an energy amount of 30,000 J or less for a time of less than 30 minutes. For example, the ultrasonic pretreatment can be performed with an energy amount of 25,000 J or less or 22,000 J or less for a time of 25 minutes or less, 20 minutes or less, or 18 minutes or less. By satisfying the above range of the energy amount and the implementation time, the effect of the ultrasonic pretreatment, that is, the improvement of dispersibility, can be maximized. If the energy amount exceeds the above range, rather, the nanoparticles may re-aggregate and the dispersibility may decrease.

[0124] The nanocellulose according to the realization example may be one that has been pretreated with a bead mill or ultrasonically. Or, the nanocellulose according to the realization example may be one that has been subjected to both bead mill pretreatment and ultrasonic pretreatment. At this time, it is preferable to perform ultrasonic pretreatment after bead mill pretreatment in terms of preventing re-aggregation and improving dispersibility.

[0125] The polydispersity index (PDI) of the biodegradable polyester resin according to the realization example is less than 2.0. For example, the polydispersity index of the biodegradable polyester resin may be less than 2.0, 1.95 or less, or 1.9 or less.

[0126] By adjusting the polydispersity index to the above range, the heat resistance can be further improved. Specifically, when the polydispersity index exceeds the above range, the heat resistance of the biodegradable polyester resin may decrease. Thereby, in the process of manufacturing a molded product such as a film using the biodegradable polyester resin, the occurrence rate of polymer degradation may increase and the processing suitability and productivity may decrease.

[0127] The polydispersity index can be calculated by the following formula A.

[0128] [Formula A] JPEG2025522301000003.jpg1152In the above formula A, Mw is the weight average molecular weight (g / mol) of the resin, and Mn is the number average molecular weight (g / mol) of the resin.

[0129] [Method for producing biodegradable polyester resin] According to one realization example, the present invention may provide a method for producing a biodegradable polyester resin, which includes a step of subjecting the biodegradable polyester polymerization composition to a polycondensation reaction at least once, wherein the metal content in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the whole weight, and the dispersion index (DI) represented by the above formula 1 is 3.0 or more.

[0130] According to one embodiment of the present invention, when a polycondensation reaction is carried out using a biodegradable polyester polymerization composition containing the inorganic filler in a specific content, the manufacturing process is simple, and by an economical and efficient method, biodegradation is possible, defects such as voids in the processing step are reduced, the tensile strength is further increased, the oxygen permeability is decreased, and a biodegradable film excellent in characteristics for packaging can be provided. Also, in terms of the process, the phenomenon of clogging of the filter during processing can be minimized, and the difference between the initial filter pressure and the final filter pressure can be reduced, so the productivity and processability are improved, and problems such as bursting of bubbles and breakage can also be solved.

[0131] Specifically, the method for producing the biodegradable polyester resin may include a first step of producing a prepolymer by ring-opening polymerization of a lactide monomer or by subjecting a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component to an esterification reaction at least once; a second step of mixing the prepolymer and the inorganic filler to obtain a biodegradable polyester polymerization composition; and a third step of subjecting the biodegradable polyester polymerization composition to a polycondensation reaction at least once.

[0132] The method for producing the biodegradable polyester resin may include a step (first step) of producing a prepolymer by ring-opening polymerization of a lactide monomer or by subjecting a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component to an esterification reaction at least once.

[0133] In the first step, the ring-opening polymerization of the lactide monomer can be carried out at 200°C to 300°C for 4 hours to 6 hours. A catalyst can be added during the ring-opening polymerization, and the catalyst can be selected from the group consisting of tin-based catalysts and tetrabutyl titanate catalysts. The catalyst can be added at 100 ppm to 1000 ppm, 200 ppm to 800 ppm, or 200 ppm to 600 ppm based on the total weight of the raw materials and auxiliary raw materials, for example, the total weight of the diol component, the aromatic dicarboxylic acid component, and the aliphatic dicarboxylic acid component.

[0134] In addition, in the first step, the step of performing the esterification reaction at least once or more using the diol component, the aromatic dicarboxylic acid component, and the aliphatic dicarboxylic acid component may include a step of mixing the diol component and the aromatic dicarboxylic acid to obtain a slurry, and a step of performing the esterification reaction at least once or more using the mixture containing the slurry and the aliphatic dicarboxylic acid, or the reaction product obtained by subjecting the slurry to the esterification reaction and the mixture containing the aliphatic dicarboxylic acid.

[0135] By mixing the diol component and the aromatic dicarboxylic acid to form a slurry, not only can the diol component and the aromatic dicarboxylic acid react uniformly, but it is also effective in accelerating the rate of the esterification reaction, so the reaction efficiency can be increased.

[0136] In particular, when the aromatic dicarboxylic acid such as terephthalic acid has complete crystallinity and is in powder form, its solubility in the diol is very low, so a homogeneous reaction may not easily occur. Therefore, the step of forming the slurry can play a very important role in providing a biodegradable polyester resin, sheet, film, and molded article having excellent physical properties according to the embodiments of the present invention and enhancing the reaction efficiency.

[0137] Also, when the step of mixing the diol component and the aromatic dicarboxylic acid to form a slurry is not performed and the esterification reaction is carried out by mixing all of the diol component, the aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid, the reaction between the diol component and the aliphatic dicarboxylic acid may proceed earlier, so it may be difficult to achieve the effects intended in the present invention.

[0138] According to an embodiment of the present invention, when the aromatic dicarboxylic acid component is terephthalic acid, the terephthalic acid has complete crystallinity and is a white crystal that sublimes at normal pressure and a temperature of about 300 °C without a melting point, and has a very low solubility in the diol component. Therefore, since a homogeneous reaction hardly occurs, if a slurrying step is performed before the esterification reaction, the surface area for reacting with the diol component can be increased within the solid matrix of terephthalic acid to induce a uniform reaction.

[0139] Also, according to an embodiment of the present invention, when the aromatic dicarboxylic acid component is dimethyl terephthalate, the slurrying step can melt the dimethyl terephthalate at about 142 °C to 170 °C and react it with the diol, so that the esterification reaction rate can proceed more rapidly and efficiently.

[0140] In addition, in the stage of slurrying, the structure and physical properties of the biodegradable polyester resin may change depending on the particle size, particle size distribution, slurrying conditions, etc. of the aromatic dicarboxylic acid component.

[0141] For example, the aromatic dicarboxylic acid component contains terephthalic acid, and the terephthalic acid has an average particle size (D50) measured by a particle size analyzer Microtrac S3500 of 400 μm or less, for example, 10 μm to 400 μm, in the particle size distribution (PSD), and the standard deviation with respect to the average particle size (D50) can be 100 or less. The standard deviation means the square root of the dispersion.

[0142] The average particle size (D50) of the terephthalic acid can be, for example, 20 μm to 200 μm, 30 μm to 180 μm, 50 μm to 150 μm, or 50 μm to 100 μm. When the average particle size (D50) of the terephthalic acid satisfies the above range, it may be more advantageous in terms of improving the solubility in the diol component and the reaction rate.

[0143] If the average particle diameter (D50) of the terephthalic acid is less than 10 μm, it is not preferable because the average particle diameter is too small and it can be converted into secondary particles aggregated from single primary particles. If the average particle diameter (D50) of the terephthalic acid exceeds 400 μm, the average particle diameter is too large, so the solubility in diol decreases and the reaction rate becomes slow, and it may be difficult to obtain a homogenization reaction.

[0144] Also, the standard deviation with respect to the average particle diameter (D50) of the terephthalic acid can be 100 or less, for example, 5 - 90, 5 - 80, 5 - 70, 10 - 70, 15 - 70, or 15 - 50. When the standard deviation with respect to the average particle diameter (D50) of the terephthalic acid satisfies the above range, it may be more advantageous in terms of improving the solubility in the diol component and the reaction rate.

[0145] Furthermore, when the average particle diameter (D50) and the standard deviation of the terephthalic acid satisfy the above range, the reaction time can be shortened by 1.5 times or more, which may be preferable in terms of reaction efficiency.

[0146] When the aromatic dicarboxylic acid component is dimethyl terephthalate, it may be in a similar range to the average particle diameter (D50) and the standard deviation of the terephthalic acid when used in a molten state or measured in a particulate state.

[0147] In the slurrying step, the diol component and the aromatic dicarboxylic acid component can be mixed and put into a slurry stirrer (tank).

[0148] According to an embodiment of the present invention, in the slurrying step, since the stirring force until slurrying is very important, the number, shape of the stirring blades of the stirrer, and the slurrying process conditions are very important.

[0149] The slurry stirrer, for example, having an anchor type at the bottom, a height to the agitator of 20 mm or more, and being provided with two or more rotating blades may be more advantageous in achieving an efficient stirring effect.

[0150] For example, the height of the slurry stirrer to the stirrer is 20 mm or more, that is, the space between the reactor and the lowermost part of the stirrer may be almost in contact. In this case, a slurry without precipitation can be obtained. If the number, shape, and / or the slurry formation process conditions of the stirring blades of the stirrer do not satisfy the above conditions, when the diol component and the aromatic dicarboxylic acid component are initially mixed, the aromatic dicarboxylic acid component may settle to the bottom, and in that case, phase separation may occur.

[0151] The slurry formation stage may include a stage of mixing a diol component and an aromatic dicarboxylic acid component and stirring at 60°C to 100°C at 50 rpm to 200 rpm for 10 minutes or more, for example, 10 minutes to 200 minutes. When the temperature, speed, and stirring time are satisfied, a uniform slurry can be obtained without phase separation, which is advantageous in terms of reaction efficiency, and the physical properties of the biodegradable polyester resin targeted in the present invention can be efficiently obtained.

[0152] The diol component may include 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or a derivative thereof.

[0153] Specifically, the diol component may include 95 mol% or more, 98 mol% or more, 99 mol% or more, or 100 mol% of 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or a derivative thereof based on the total number of moles of the diol component. By including the diol component of 1,4-butanediol, 1,2-ethanediol, 1,2-ethanediol, 1,3-propanediol, or a derivative thereof within the above range, the biodegradability, hydrolyzability, and physical properties of the biodegradable polyester resin or the biodegradable polyester sheet, film, or molded product obtained using the same can be improved.

[0154] The diol component may be charged at once or dividedly. For example, the diol component may be charged separately when mixing with the aromatic dicarboxylic acid and when mixing with the aliphatic dicarboxylic acid.

[0155] The aromatic dicarboxylic acid component may include one or more selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof. Specifically, the aromatic dicarboxylic acid component may be terephthalic acid or dimethyl terephthalate.

[0156] Further, the aromatic dicarboxylic acid component may be used in an amount of 40 mol% to 60 mol%, 42 mol% to 58 mol%, 44 mol% to 58 mol%, 44 mol% to 57 mol%, 44 mol% to 55 mol%, 44 mol% to 53 mol%, or 46 mol% to 52 mol% based on the total number of moles of the dicarboxylic acid component.

[0157] Controlling the content of the aromatic dicarboxylic acid within the above range is more advantageous for obtaining the effects of the present invention, and can improve the physical properties, biodegradability, and hydrolysis reduction rate of the biodegradable polyester sheet, film, or molded article produced using the same.

[0158] Note that, by using the slurry, the reaction time of the esterification reaction can be shortened. For example, by using the slurry, the reaction time can be shortened by 1.5 times or more.

[0159] The esterification reaction may be carried out at least once or more.

[0160] According to one implementation example of the present invention, in the esterification reaction, an aliphatic dicarboxylic acid component, or a diol component and an aliphatic dicarboxylic acid component may be added to the slurry to carry out the esterification reaction once.

[0161] The esterification reaction can be carried out at 250 °C or lower for 0.5 hours to 5 hours. Specifically, the esterification reaction can be carried out at 180 °C to 250 °C, 185 °C to 240 °C, or 200 °C to 240 °C under normal pressure or reduced pressure until the by-product water theoretically reaches 95%. For example, the esterification reaction can be carried out for 0.5 hours to 4.5 hours, 0.5 hours to 3.5 hours, or 1 hour to 3 hours, but is not limited thereto.

[0162] The number average molecular weight of the prepolymer can be 500 g / mol to 10,000 g / mol. For example, the number average molecular weight of the prepolymer can be 500 g / mol to 8500 g / mol, 500 g / mol to 8000 g / mol, 500 g / mol to 7000 g / mol, 500 g / mol to 5000 g / mol, or 500 g / mol to 2000 g / mol. By the number average molecular weight of the prepolymer satisfying the above range, the molecular weight of the polymer can be efficiently increased in the polycondensation reaction.

[0163] According to another embodiment of the present invention, the esterification reaction includes a step of subjecting the slurry to a primary esterification reaction and a step of adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid to the reaction product of the primary esterification reaction to carry out a secondary esterification reaction, and the esterification reaction can be carried out two or more times.

[0164] When the esterification reaction is carried out two or more times, the reaction stability and reaction uniformity can be improved compared to the case where the esterification reaction is carried out once.

[0165] The primary esterification reaction and the secondary esterification reaction can each be carried out at 250°C or lower for 0.5 to 5 hours. Specifically, the primary esterification reaction and the secondary esterification reaction can each be carried out at normal pressure at 180°C to 250°C, 185°C to 240°C, or 200°C to 240°C until the by-product water theoretically reaches 95%. For example, the primary esterification reaction and the secondary esterification reaction can each be carried out for 0.5 to 4.5 hours, 0.5 to 3.5 hours, or 1 to 3 hours, but are not limited thereto.

[0166] The aliphatic dicarboxylic acid component may include adipic acid, succinic acid, sebacic acid, or a derivative thereof. Specifically, the aliphatic dicarboxylic acid component may include adipic acid or succinic acid.

[0167] Also, the aliphatic dicarboxylic acid component can be used in an amount of 40 mol% to 60 mol%, 42 mol% to 58 mol%, 42 mol% to 56 mol%, 43 mol% to 56 mol%, 45 mol% to 56 mol%, 47 mol% to 56 mol%, or 48 mol% to 54 mol% based on the total number of moles of the dicarboxylic acid component.

[0168] Controlling the content of the aliphatic dicarboxylic acid within the above range is more advantageous for obtaining the effects of the present invention, and can further improve the impact resistance and durability of molded products such as biodegradable polyester sheets, films, or injection-molded products made using the same.

[0169] In particular, since the aliphatic dicarboxylic acid component consists of a linear chain, it can affect the mechanical properties of the biodegradable polyester resin and the blow moldability or injection moldability.

[0170] Specifically, if the content of the aliphatic dicarboxylic acid component is too high, the mechanical properties of the biodegradable polyester resin may decrease, and the blow moldability and injection moldability of a biodegradable polyester sheet or film made from the biodegradable polyester resin may deteriorate.

[0171] At the time of the esterification reaction, for example, when performing the primary and secondary esterification reactions, nanocellulose can be further added at the time of the primary esterification reaction, the time of the secondary esterification reaction, or both.

[0172] Specifically, when performing the esterification reaction once, nanocellulose can be further added at the time of the esterification reaction, for example, when adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid.

[0173] When the esterification reaction is performed two or more times, nanocellulose can be added at the time of the primary esterification reaction, the time of the secondary esterification reaction, or both. For example, the nanocellulose can be added at the time of the secondary esterification reaction, that is, when adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid, or at the initial stage of the esterification reaction. Thereby, it can be efficient in nanocellulose dispersion. In particular, by adding the nanocellulose, it is preferable in terms of the mechanical properties and thermal properties of the biodegradable polyester resin, and can also improve the strength, impact resistance, and durability of the biodegradable polyester sheet, film, or molded product.

[0174] The specific types of the nanocellulose are as described above.

[0175] Also, the content of the nanocellulose may be, for example, 3000 ppm or less, 2500 ppm or less, 2000 ppm or less, 1800 ppm or less, 1500 ppm or less, 1000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, 500 ppm or less, or 400 ppm or less, and may be 100 ppm or more, 150 ppm or more, 200 ppm or more, 250 ppm or more, or 300 ppm or more, based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By the content of the nanocellulose satisfying the above range, the biodegradability and mechanical properties such as strength can be further improved.

[0176] In the first stage, after adding a titanium-based catalyst or a germanium-based catalyst, the esterification reaction can be initiated.

[0177] Specifically, when performing the esterification reaction once, a mixture containing a diol component, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid can be produced, and after adding the catalyst, the esterification reaction can be carried out.

[0178] When the esterification reaction is carried out two or more times, the catalyst can be added to the reactor before each esterification reaction, and then the esterification reaction can be initiated. Specifically, after putting the slurry into the reactor and adding the catalyst, a primary esterification reaction can be carried out, and / or an aliphatic dicarboxylic acid, or a diol component and an aliphatic dicarboxylic acid can be added to the reaction product obtained by subjecting the slurry to a primary esterification reaction. After adding the catalyst, a secondary esterification reaction can be carried out.

[0179] Specifically, the biodegradable polyester resin may contain at least one titanium-based catalyst selected from the group consisting of titanium isopropoxide, antimony trioxide, dibutyltin oxide, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, antimony acetate, calcium acetate, and magnesium acetate, or at least one germanium-based catalyst selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethylgermanium, tetraethylgermanium, and germanium sulfide.

[0180] In addition, the content of the catalyst may be 100 ppm to 1000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. For example, the biodegradable polyester resin may contain a titanium-based catalyst or a germanium-based catalyst in an amount of 100 ppm to 800 ppm, 150 ppm to 700 ppm, 200 ppm to 600 ppm, or 250 ppm to 550 ppm. By the content of the catalyst satisfying the above range, the physical properties can be further improved.

[0181] During the second-stage esterification reaction, at the end of the esterification reaction, or both, a phosphorus-based stabilizer can be further added.

[0182] Specifically, when the esterification reaction is carried out once, a phosphorus-based stabilizer can be further added during the esterification reaction, at the end of the esterification reaction, or both.

[0183] Also, when the esterification reaction is carried out two or more times, a phosphorus-based stabilizer can be further added during the first-stage esterification reaction, during the second-stage esterification reaction, or both, or at the end of the first-stage esterification reaction or at the end of the second-stage esterification reaction.

[0184] Specifically, the biodegradable polyester resin may further contain one or more phosphorus-based stabilizers selected from the group consisting of amine-based high-temperature heat stabilizers such as tetraethylenepentamine, phosphoric acid, phosphorous acid, polyphosphoric acid, trimethyl phosphate, triethyl phosphate, triethyl phosphonoacetate, trimethylphosphine, and triphenylphosphine.

[0185] The content of the phosphorus-based stabilizer may be 3000 ppm or less based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Specifically, the content of the phosphorus-based stabilizer may be, for example, 10 ppm to 3000 ppm, 20 ppm to 2000 ppm, 20 ppm to 1500 ppm, or 20 ppm to 1000 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. By the content of the phosphorus-based stabilizer satisfying the above range, the degradation of the polymer due to high temperature during the reaction process can be controlled, the end groups of the polymer can be reduced, and the color can be improved.

[0186] After the completion of the esterification reaction, one or more selected from the group consisting of additives such as silica, potassium, titanium dioxide, or magnesium, and color correctors such as cobalt acetate can be further added. That is, after the completion of the esterification reaction, the above additives and / or color correctors can be added and stabilized, and then the polycondensation reaction can proceed.

[0187] The method for producing the biodegradable polyester resin may include a step (second step) of mixing the prepolymer and the inorganic filler to obtain a biodegradable polyester polymerization composition.

[0188] That is, according to an implementation example of the present invention, an inorganic filler may be added after the completion of the esterification reaction in the first step.

[0189] For example, when performing the esterification reaction once, the inorganic filler can be added after the completion of the esterification reaction. When performing the esterification reaction twice, the inorganic filler can be added after the completion of the secondary esterification reaction. The usage amount and type of the inorganic filler are as described above.

[0190] In particular, when the inorganic filler is added after the completion of the esterification reaction, the dispersibility of the inorganic filler can be improved, so aggregation can be minimized, the filter clogging phenomenon during processing can be minimized, and the difference between the initial filter pressure and the filter pressure after extrusion can be minimized. In addition, the occurrence of defects such as voids during the blow molding process and extrusion stretching can be minimized, a stable processing process can be achieved, problems such as bubbles bursting or fractures occurring can be minimized, and the excellent physical properties aimed at in the present invention can be realized without defects.

[0191] If the inorganic filler is added before the esterification reaction or at the time of the esterification reaction, even if the dispersion is good in the esterification reaction stage, the viscosity may increase in the polycondensation stage, and thermal decomposition or depolymerization may occur.

[0192] Also, when the inorganic filler is added after the polycondensation reaction or when the inorganic filler is compounded (blended) with the final biodegradable polyester resin, not only a large amount of inorganic filler is required to achieve the above effect, but also the compatibility between the biodegradable polyester resin and the inorganic filler is not good. Therefore, during the blow molding process and / or extrusion stretching, voids may occur and bubbles may burst or fractures may occur, resulting in a decrease in productivity and problems acting as internal and surface defects of the film.

[0193] Further, according to one realization example of the present invention, the inorganic filler may be a pretreated inorganic filler. When the pretreated inorganic filler is used, the particles of the inorganic filler are likely to be dispersed even in the polycondensation reaction stage. Therefore, not only can the polymerization reaction proceed smoothly, but also the phenomenon of filter clogging can be prevented, the generation of voids can be minimized, the processability, productivity, and moldability can be improved, and a biodegradable polyester sheet, film, or molded product with excellent quality can be provided.

[0194] The pretreatment method of the inorganic filler is as described above.

[0195] Also, the inorganic filler may be mixed with one or more selected from the group consisting of ultrapure water and a diol component, manufactured at a slurry concentration of 10% by weight to 30% by weight, and then pretreated by the method described above, and added in a slurry state (inorganic filler slurry).

[0196] According to one embodiment of the present invention, the inorganic filler may be added in a drop manner. For example, the drop method is a method of introducing the inorganic filler or a slurry containing the same into the reactor at a drop rate of 10 kg / min or less so that the inorganic filler can directly fall onto the reactant without directly falling onto the stirrer or flowing along the wall surface of the reactor.

[0197] The content of the inorganic filler is as described above.

[0198] The method for producing the biodegradable polyester resin may include a step (third step) of subjecting the biodegradable polyester polymerization composition to a polycondensation reaction at least once or more.

[0199] The polycondensation reaction can be carried out at 180°C to 280°C and 1.0 torr or less for 1 hour to 5 hours. For example, the polycondensation reaction can be carried out at 190°C to 270°C, 210°C to 260°C, or 230°C to 255°C, and at 0.9 torr or less, 0.7 torr or less, 0.2 torr to 1.0 torr, 0.3 torr to 0.9 torr, or 0.4 torr to 0.6 torr, and can be carried out for 1.5 hours to 10 hours, 2 hours to 8 hours, or 2.5 hours to 6 hours.

[0200] Also, the polycondensation reaction can be carried out one or more times.

[0201] Specifically, the biodegradable polyester polymerization composition is transferred to the pre-polycondensation stage, and pre-polycondensation is carried out at 180°C to 280°C and under a low vacuum of 100 to 300 torr for 1 hour to 5 hours, and then transferred to the final polycondensation stage. For example, by a disc ring type reactor, final polycondensation can be carried out at 180°C to 280°C and under 0.5 torr for 2 hours to 5 hours.

[0202] Also, before the polycondensation reaction, a titanium-based catalyst or a germanium-based catalyst can be further added to the prepolymer or the biodegradable polyester polymerization composition. Also, before the polycondensation reaction, additives such as silica, potassium, or magnesium; amine stabilizers such as trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, phosphorous acid, or tetraethylenepentamine; and one or more selected from the group consisting of polymerization catalysts such as antimony trioxide or tetrabutyl titanate can be further added to the prepolymer or the biodegradable polyester polymerization composition.

[0203] The number average molecular weight of the polymer obtained by the polycondensation may exceed 30,000 g / mol. For example, the number average molecular weight of the polymer may be 40,000 g / mol or more, 41,000 g / mol or more, 42,000 g / mol or more, or 43,000 g / mol or more. By satisfying the above range of the number average molecular weight of the polymer, the physical properties and processability can be further improved.

[0204] Thereafter, pellets can be produced from the polymer (the fourth step).

[0205] Specifically, after inducing the crystallization of the polymer at 100 °C or lower, 70 °C or lower, or 60 °C or lower, the polymer can be cut to produce polyester resin pellets.

[0206] The cutting step can be carried out without limitation using any pellet cutter used in the industry, and the pellets can have various shapes. Examples of the pellet cutting method may include an under water cutting method or a strand cutting method.

[0207] [Biodegradable polyester sheet] On the other hand, in one embodiment of the present invention, a biodegradable polyester sheet can be obtained using the biodegradable polyester resin.

[0208] Specifically, the biodegradable polyester sheet is a biodegradable polyester sheet containing the biodegradable polyester resin, wherein the metal content in the biodegradable polyester resin is 0.01 wt% to 7 wt% or less based on the total weight, and the dispersion index (DI) represented by the formula 1 can be 3.0 or more.

[0209] The biodegradable polyester sheet can be produced using the biodegradable polyester resin or polyester resin pellets.

[0210] Specifically, the produced biodegradable polyester resin is, for example, placed in a stainless steel (SUS) frame and held at about 150°C to 300°C for 1 minute to 30 minutes under a pressure of 5 MPa to 20 MPa using a hot press, then desorbed, and immediately cooled with water at 18°C to 25°C for about 10 seconds to 5 minutes to produce a biodegradable polyester sheet.

[0211] The biodegradable polyester sheet has a center line average roughness (Ra) of 50 nm, a haze (Hz) of 50% or less, a coefficient of static friction (FC) of 5 or less, 800 CC / m 2 ·day·atm or less of oxygen permeability (OP), and can satisfy at least one characteristic selected from the characteristics of a tensile strength (TS) of 35 MPa or more.

[0212] The specific measurement methods and specific ranges of the above physical properties are as described above.

[0213] [Biodegradable Polyester Film] In one embodiment, the present invention provides a biodegradable polyester film containing a biodegradable polyester resin, wherein the content of metal in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the total weight, and the dispersion index (DI) represented by the formula 1 is 3.0 or more.

[0214] The thickness of the biodegradable polyester film can be 5 μm to 200 μm. For example, the thickness of the biodegradable polyester film can be 5 μm to 180 μm, 5 μm to 160 μm, 10 μm to 150 μm, 15 μm to 130 μm, 20 μm to 100 μm, 25 μm to 80 μm, or 25 μm to 60 μm.

[0215] On the other hand, the biodegradable polyester film can be produced using the biodegradable polyester resin or biodegradable polyester resin pellets.

[0216] Specifically, the method for manufacturing the biodegradable polyester film may include a first step of subjecting a lactide monomer to ring-opening polymerization or performing an esterification reaction at least once or more using a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component to produce a prepolymer; a second step of mixing the prepolymer and an inorganic filler to obtain a biodegradable polyester polymerization composition; a third step of subjecting the biodegradable polyester polymerization composition to a polycondensation reaction at least once or more to obtain a polymer; a fourth step of producing pellets from the polymer; and a fifth step of drying and melt-extruding the pellets.

[0217] In addition, in the first step, the step of performing an esterification reaction at least once or more using the diol component, the aromatic dicarboxylic acid component, and the aliphatic dicarboxylic acid component may include a step of mixing and pretreating the diol component and the aromatic dicarboxylic acid to obtain a slurry, and a step of performing an esterification reaction at least once or more using a mixture containing the slurry and the aliphatic dicarboxylic acid, or a mixture containing a reaction product obtained by subjecting the slurry to an esterification reaction and the aliphatic dicarboxylic acid.

[0218] The first to fourth steps are as described above.

[0219] In the fifth step, the drying may be performed at a temperature of 60°C to 100°C for 2 hours to 12 hours. Specifically, the drying may be performed at a temperature of 65°C to 95°C, 70°C to 90°C, or 75°C to 85°C for 3 hours to 12 hours or 4 hours to 10 hours. By satisfying the above range for the drying process conditions of the pellets, the quality of the produced biodegradable polyester film or molded product can be further improved.

[0220] In the fifth step, the melt-extrusion may be performed at a temperature of 270°C or lower. For example, the melt-extrusion may be performed at a temperature of 265°C or lower, 260°C or lower, 255°C or lower, 150°C to 270°C, 150°C to 255°C, or 150°C to 240°C. The melt-extrusion may be performed in a blown film process.

[0221] (Example) The above content will be further described in detail by the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited to these only.

[0222] (Example 1) [Production of biodegradable polyester resin] <First stage: Obtaining a prepolymer>[[]] L-lactide (L-lactide 100%, Total Corbion) was put into a reactor, and 400 ppm of tin octoate was added thereto as a catalyst. Then, ring-opening polymerization was carried out at about 240 °C for about 2 hours to obtain a prepolymer.

[0223] <Second stage: Obtaining a biodegradable polyester polymerization composition>[[]] To the prepolymer obtained in the first stage, 50 ppm of a heat stabilizer and 1 wt% of TiO2 (Ohmiya Co., Ltd.) as an inorganic filler were added based on the total weight of the biodegradable polyester polymerization composition to obtain a biodegradable polyester polymerization composition.

[0224] At this time, the inorganic filler was an inorganic filler pretreated by a mixer tank, with D50 being 1.5 μm and a specific surface area of 50 m 2 / g. The pretreatment was carried out by stirring the inorganic filler at about 300 rpm for about 1 hour at room temperature using a slurry tank with a dust explosion-proof equipment specification. Also, the inorganic filler was put into the esterification reactor after the esterification (ES) reaction and stabilized for 10 minutes.

[0225] <Third stage: Performing a polycondensation reaction>[[]] The biodegradable polyester polymerization composition obtained in the second stage was continuously transferred to a preliminary polycondensation stage and reacted at about 240 °C under a low vacuum of about 100 torr for about 2 hours.

[0226] Thereafter, it was transferred to the final polycondensation stage, and the final polycondensation reaction was carried out in a disk-ring reactor under 0.5 torr for about 3 hours. Thereafter, while removing the residual 1,4-butanediol and by-products, the viscosity was increased at a high viscosity for about 3 hours to produce a polymer having a number average molecular weight of about 60,000 g / mol. The viscosity immediately after polymerization was 7200 poise.

[0227] <Step 4: Process of manufacturing pellets> The polymer obtained in the third stage was induced to crystallize at 50 °C in an under-water cutter (UWC), and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0228] [Manufacture of biodegradable polyester sheet] After preparing two Teflon sheets, a stainless steel (SUS) frame (area 12 cm × 12 cm) was placed on one Teflon sheet. After putting about 7 g of the manufactured polyester resin pellets into the stainless steel (SUS) frame (area 12 cm × 12 cm), it was covered with the other Teflon sheet and placed in the center of a hot press (WL1600SA, WITHLAB) having a surface size of about 25 cm × 25 cm. This was held at about 240 °C under a pressure of about 10 MPa for about 3 minutes, then desorbed, and immediately cooled with water at about 20 °C for about 30 seconds to manufacture a biodegradable polyester sheet having an area of about 10 cm × 10 cm and a thickness of about 300 μm.

[0229] [Manufacture of biodegradable polyester film] The biodegradable polyester resin pellets were dried at 80 °C for 5 hours, and then melt-extruded at 240 °C using a blown film extruder (Blown Film Extrusion Line, Yuzhin Engineering) to manufacture a biodegradable polyester film having a thickness of 50 μm.

[0230] (Example 2) [Manufacture of biodegradable polyester resin] <Step 1: Step of obtaining a prepolymer> Terephthalic acid (TPA) and adipic acid (AA) were used at 48 mol% and 52 mol%, respectively.

[0231] 1,4-Butanediol (1,4-BDO) / terephthalic acid (TPA) was mixed at 1.5 (glycol / acid (G / A)), and charged into a slurry tank (the bottom of the slurry tank is of the anchor type, and two flat type agitators are provided at the upper part). At this time, the D50 of the terephthalic acid (TPA) was 200 μm, and the standard deviation (SD) with respect to the D50 of the terephthalic acid (TPA) was 20%.

[0232] Next, the mixture was stirred at 70 °C and 150 rpm for 30 minutes to obtain a slurry without phase separation. The slurry was charged into a reactor through a supply line, and after adding 500 ppm of tetrabutyl titanate (Tyzor (registered trademark), TnBT, Dupont), a titanium-based catalyst, a primary esterification reaction was carried out at 210 °C and normal pressure for about 1.5 hours until 95% of the by-product water was discharged.

[0233] To the primary esterification reaction product, 52 mol% of 1,4-butanediol (1,4-BDO) based on the total molar number of the diol component, 52 mol% of adipic acid (AA) based on the total molar number of the dicarboxylic acid component (G / A is 1.1), and tetrabutyl titanate (Tyzor (registered trademark), TnBT, Dupont), a titanium-based catalyst, were added at 200 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Then, a secondary esterification reaction was carried out at 210 °C and normal pressure for about 2 hours until 95% of the by-product water was discharged to produce a prepolymer having a number average molecular weight of about 45000 g / mol.

[0234] <Step 2: Obtaining a biodegradable polyester polymerization composition> To the prepolymer obtained in the first stage, 100 ppm of triethyl phosphate heat stabilizer was further added based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. Based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid, 5% by weight of SiO2 (Fuji Silysia Chemical Ltd.) as an inorganic filler, 100 ppm of siloxane polyol (Chisso Corporation) as a dispersant, and 900 ppm of cellulose nanocrystal (CNC) (particle size 190 nm) treated at 2000 rpm for 15 minutes were additionally added to obtain a biodegradable polyester polymerization composition.

[0235] At this time, the inorganic filler is an inorganic filler pretreated by the same method as in Example 1, with a D50 of 2.8 μm and a specific surface area of 250 m 2 / g.

[0236] <Third stage: Step of carrying out polycondensation reaction> The biodegradable polyester polymerization composition obtained in the second stage was continuously transferred to a preliminary polycondensation stage and reacted at 240 °C under a low vacuum of about 200 torr for about 3 hours.

[0237] Thereafter, it was transferred to the final polycondensation stage and polycondensation reaction was carried out at about 0.5 torr for about 3 hours using a disc ring type reactor. Thereafter, while removing the residual 1,4-butanediol and by-products, the molecular weight was increased at a high viscosity for about 3 hours to produce a polymer having a number average molecular weight of about 60,000 g / mol. The viscosity immediately after polymerization was 9800 poise.

[0238] <Fourth stage: Step of producing pellets> The polymer obtained in the third stage was induced to crystallize at 50 °C in an under water cutter (UWC), and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0239] [Production of biodegradable polyester sheet and film] Performed in the same manner as in Example 1, a polyester sheet and a film were each produced.

[0240] (Example 3) As shown in Table 1 below, using CaCO3 as the inorganic filler, changing its D50 and specific surface area, and changing the input amount, and except for not adding CNC, it was performed in the same manner as in Example 2 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0241] (Example 4) As shown in Table 1 below, except for changing the D50 and specific surface area of the inorganic filler and changing the input amount, it was performed in the same manner as in Example 2 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0242] (Example 5) As shown in Table 1 below, using TiO2 as the inorganic filler, changing its D50 and specific surface area, and changing the input amount, and except for not adding CNC, it was performed in the same manner as in Example 2 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0243] (Comparative Example 1) As shown in Table 1 below, except for not adding TiO2 as the inorganic filler after the esterification reaction was completed and mixing (compounding) it with the polymer produced after polycondensation, it was performed in the same manner as in Example 5 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0244] (Comparative Example 2) As shown in Table 1 below, except for not using an inorganic filler, it was performed in the same manner as in Example 5 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0245] (Comparative Example 3) As shown in Table 1 below, the D50 and specific surface area of SiO2 as the inorganic filler were changed, and the input amount was changed. Except for not adding CNC, it was carried out in the same manner as in Example 2 above to produce a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film.

[0246] (Evaluation Example) For the biodegradable polyester resin, biodegradable polyester sheet, or biodegradable polyester film according to the above Examples and Comparative Examples, the following physical properties were measured and evaluated. The results are shown in Table 1 and Table 2 below.

[0247] (Evaluation Example 1: Filter Pressure) In a blown film extrusion line (Blown Film Extrusion Line, manufactured by Yuzhin Engineering Co., Ltd.), a single screw was used. After installing a 40-μm mat filter (manufactured by LIANDA Co., Ltd.) at the rear end of the gear pump in the extruder, when the biodegradable polyester resin was extruded at about 240 °C, the initial filter pressure (FP0) applied to the filter was measured, and after extrusion for 2 hours, the filter pressure (FP2) applied to the filter was measured respectively.

[0248] In addition, the filter pressure difference (ΔFP) between the initial filter pressure (FP0) represented by the following formula 3 and the filter pressure (FP2) after extrusion for 2 hours was calculated, and the results are shown in Table 1.

[0249] [Formula 3] ΔFP = │FP0 - FP2│ In the above formula 3, FP0 is the initial pressure (kg / cm 2 ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C, FP2 is the pressure (kg / cm 2 ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C for 2 hours.

[0250] (Evaluation Example 2: Metal Content and Inorganic Content in Resin) The metal content and inorganic content in the biodegradable polyester resin obtained in the above Examples and Comparative Examples were measured using a thermogravimetric analyzer (TGA, TA Instruments) and inductively coupled plasma optical emission spectrometry (ICP / OES, Thermo Scientific), respectively.

[0251] Specifically, using a thermogravimetric analyzer, while raising the temperature from room temperature to 800°C, all the organic substances were burned, and the content of the remaining residual inorganic matter (Ash) was measured.

[0252] Also, using inductively coupled plasma optical emission spectrometry, the amount of specific metal elements in the sample was quantitatively measured in ppm units.

[0253] (Evaluation Example 3: Particle Size and Specific Surface Area) The particle sizes of terephthalic acid (TPA) and the inorganic additive were measured using a particle size analyzer Microtrac S3500 (S3500, Microtrac) with a particle size distribution (PSD) under the following conditions. The measurement range was selected as 0.02 μm to 2000 μm to obtain the average particle size (D50) and standard deviation (Standard Deviation, SD).

[0254] - Use environment: Temperature 10°C to 35°C, humidity 90%RH, non-condensing max. - The D50 and SD, which are the average particle size distributions by interval, were measured.

[0255] The standard deviation means the square root of the dispersion and can be calculated using software.

[0256] In addition, the specific surface area of the inorganic additive was measured using a BET specific surface area analyzer (ASAP 2020, Micromeritics).

[0257] (Evaluation Example 4: Viscosity) Using an RDS (Rheometrics Dynamic Spectrometer, Discovery HR 30, TA Instrument) which is a dynamic viscometer, the dynamic viscosity was measured while increasing the angular velocity per second (1 rad / sec) at a temperature of 240°C (1 rad / sec is 9.5 rpm). In the case of the resin viscosity, the viscosity (poise) immediately after polymerization was measured.

[0258] (Evaluation Example 5: Surface Roughness (Ra)) The surface roughness was measured with an AFM device (Atomic Force Microscope, XE-150, Park System).

[0259] Specifically, after preparing a test piece by cutting it to a length of 3 cm and a width of 3 cm according to the JIS B0601 standard, the two-dimensional surface roughness was measured at five or more locations on the surface of the test piece using the surface roughness meter, and the center line average roughness (Ra) was determined.

[0260] The center line average roughness (Ra) is the arithmetic mean roughness of the deviation of the roughness curve with respect to the average line according to JIS 0161. It is shown as the value obtained by obtaining the total of the upper and lower sides on the center line of the reference length and dividing that value by the length of the measurement section.

[0261] (Evaluation Example 6: Haze) The haze was evaluated using a haze meter (haze-gard i, BYK Gardner, Germany). Specifically, after preparing a test piece by cutting it to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to the ASTM D1003 standard, the haze (%) was determined as shown in Equation 4 below using the haze meter. [Equation 4] Haze (%) = (total scattered light / total transmitted light) × 100%

[0262] (Evaluation Example 7: Coefficient of Static Friction) Using a friction coefficient tester (QM110CF, QMESYS), the coefficient of static friction of the biodegradable polyester sheet test piece of the example or comparative example was measured.

[0263] In accordance with ASTM D1894, one side of a stainless steel (SUS) was brought into contact with the biodegradable polyester sheet of the example or comparative example, and the coefficient of static friction when sliding was measured.

[0264] (Evaluation Example 8: Oxygen Permeability (OP)) Using OX-TRAN 702 from Mocon, the oxygen permeability of the biodegradable polyester sheet test piece of the example or comparative example was measured.

[0265] Specifically, the oxygen permeability was measured at a temperature of 25°C and a relative humidity of 0% R.H., and in accordance with ASTM D3985, the measurement sample size was 50 cm 2 and measured. The final unit of the oxygen permeability is expressed in CC / m 2 ·day·atm, which means that the greater the value of the oxygen permeability, the poorer the oxygen barrier property.

[0266] (Evaluation Example 9: Tensile Strength (TS)) After cutting the biodegradable polyester sheet produced in the example or comparative example into test pieces according to the ASTM D638 V-type standard, an experiment was conducted at a tensile speed of 100 mm / min using a universal testing machine (UTM 4206-001) from Instron, and then the tensile strength (kgf / mm 2 =9.8 MPa) was measured by the program built into the device.

[0267] (Evaluation Example 10: Dispersion Index (DI)) Using the values of oxygen permeability (OP) and tensile strength (TS) measured in Evaluation Examples 8 and 9 above, the dispersion index (DI) represented by the following formula 1 was calculated.

[0268] [Formula 1] JPEG2025522301000004.jpg1466 In the above formula 1, TS and OP are numerical values excluding the units measured on the biodegradable polyester sheet test piece made of the biodegradable polyester resin, The TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing a test piece according to the ASTM D638 V standard. The OP is the oxygen permeability (CC / m 2 ·day·atm) measured at a temperature of 25 °C and a relative humidity (RH) of 0% using an OX-TRAN 702 after preparing a test piece with a thickness of 500 μm in accordance with ASTM D3985.

[0269] (Evaluation Example 11: Processability Reduction Index (PRI)) Using the values of the center line average roughness (Ra) and haze (Hz) measured in Evaluation Examples 5 and 6 above, the processability reduction index (PRI) represented by the following formula 2 was calculated.

[0270] [Formula 2] Processability Reduction Index (PRI) = Ra + Hz In the above formula 2, Ra and Hz are numerical values excluding the units measured on a biodegradable polyester sheet test piece manufactured from the biodegradable polyester resin. The Ra is the center line average roughness (Ra) (nm) calculated by measuring the two-dimensional surface roughness at five or more points on the surface of the test piece using a surface roughness meter after preparing a test piece by cutting it to a length of 3 cm and a width of 3 cm according to the JIS B0601 standard. The Hz is the haze (%) measured using a haze meter after preparing a test piece by cutting it to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to the ASTM D1003 standard.

[0271] [Table 1]

[0272] [Table 2]

[0273] As can be seen from Tables 1 and 2 above, when a polycondensation reaction is carried out using a biodegradable polyester polymerization composition containing an inorganic filler in an amount of 0.1% by weight to 10% by weight, since the dispersibility is excellent during the polycondensation process, not only the viscosity of the biodegradable polyester resin produced from the biodegradable composition, but also the metal content and the dispersion index (DI) in the resin could be adjusted to an optimal range. Further, the processability reduction index (PRI) and the difference in filter pressure (ΔFP) of the biodegradable polyester resin could be controlled within a specific range, whereby the surface roughness, haze, coefficient of static friction, oxygen permeability, and tensile strength of the produced biodegradable polyester sheet could be improved overall.

[0274] Specifically, when the polycondensation reaction was carried out using the biodegradable polyester polymerization compositions of Examples 1 to 5, since the dispersibility was excellent, the difference in the initial filter pressure during processing and the filter pressure after 2 hours of extrusion (ΔFP) was 49 kg / cm 2 as follows, which was very low compared to the case of using the biodegradable polyester polymerization compositions of Comparative Examples 1 to 3. The viscosity of the biodegradable polyester resin obtained using this was 7,200 poises to 11,000 poises, the dispersion index (DI) was 4.68 or more, and the metal content in the biodegradable polyester resin could be realized within an appropriate range of 0.62 to 6.03. The generation of voids was reduced in the processing step, an excellent tensile strength of 36 MPa to 43 MPa was realized, and a low oxygen permeability of 770 cc / m 2 ·day·atm or less could be realized.

[0275] Further, the biodegradable polyester sheet obtained using the biodegradable polyester polymerization composition had a haze of 53% or less, a center line average roughness (Ra) of 46 nm or less, a coefficient of static friction as low as 3.1 or less, and a processability reduction index (PRI) of 99 or less, realizing optimal physical properties capable of improving the dispersibility and processability.

[0276] On the other hand, when a biodegradable polyester polymerization composition containing no inorganic additive is used as in Comparative Example 2, the coefficient of static friction of the biodegradable polyester sheet produced thereby is as high as 9.8, and the oxygen permeability is 1020 cc / m 2 ·day·atm, which is significantly increased compared to the biodegradable polyester sheets of Examples 1 to 5.

[0277] Also, in the case of a biodegradable polyester resin containing an excessive amount of inorganic additive as in Comparative Example 3, the dispersion index (DI) is as low as 2.20 and the processability reduction index (PRI) is as high as 271. Therefore, it can be confirmed that the dispersibility and processability deteriorate. Above all, the filter pressure continued to rise during processing, resulting in the rupture of the filter.

[0278] On the other hand, it can be confirmed that the physical properties of the biodegradable polyester resin, sheet, and film change significantly depending on the timing of addition of the inorganic filler.

[0279] Specifically, as in Comparative Example 1, when the inorganic additive is compounded with the biodegradable polyester resin obtained after polycondensation, the dispersibility decreases, and the difference (ΔFP) between the initial filter pressure and the filter pressure after 2 hours of extrusion is 104 kg / cm 2 Compared with the examples in which the inorganic additive was added after the esterification (ES) reaction and before the polycondensation reaction, the difference (ΔFP) in the filter pressure increased significantly, the viscosity of the biodegradable polyester resin decreased rapidly to 7000 poises or less, the haze and oxygen permeability also increased significantly, and the tensile strength decreased, making it impossible to realize physical properties suitable for packaging materials.

[0280] Furthermore, it was confirmed that the dispersibility and processability also changed depending on the D50 and specific surface area of the inorganic filler, and the addition of nanocellulose, and the physical properties of the biodegradable polyester resin, or the biodegradable polyester sheet or film using the same changed.

Claims

1. A biodegradable polyester polymerization composition comprising an aliphatic polyester polymerization composition or an aliphatic-aromatic polyester polymerization composition and an inorganic filler, wherein the aliphatic polyester polymerization composition is selected from the group consisting of lactide monomers and their ring-opening prepolymers, the aliphatic-aromatic polyester polymerization composition is selected from the group consisting of a monomer composition containing a diol component and a dicarboxylic acid component and a prepolymer of part or all of the monomer composition, the inorganic filler is contained in an amount of 0.1% by weight to 10% by weight based on the total weight of the biodegradable polyester polymerization composition, and the biodegradable polyester polymerization composition has a viscosity of 5000 to 15000 poises at 240°C.

2. The inorganic filler is SiO ２ , CaCO ３ , TiO ２ , BaSO ４ , and Al ２ O ３ The biodegradable polyester polymerization composition according to claim 1, comprising one or more selected from the group consisting of

3. The inorganic filler is 1000 m ２ / g or less in specific surface area (by the BET method) and 15 μm or less in average particle diameter (D50), and the biodegradable polyester polymerization composition according to claim 1.

4. The biodegradable polyester polymerization composition according to claim 1, wherein the inorganic filler is an inorganic filler pretreated by one or more methods selected from ultrasonic treatment, mixer tank, high-pressure homogenizer, and pretreatment with a dispersant.

5. A biodegradable polyester resin formed from the biodegradable polyester polymerization composition of claim 1, wherein the content of metal in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the total weight, and the biodegradable polyester resin has a dispersion index (DI) represented by the following formula 1 of 3.0 or more: [Formula 1] In the formula 1, TS and OP are numerical values excluding the units measured on a biodegradable polyester sheet test piece manufactured from the biodegradable polyester resin, the TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing a test piece according to ASTM D638 Type V standard, The OP was the oxygen permeability (CC / m ２ ·day·atm) measured at a temperature of 25°C and a relative humidity (RH) of 0% using an OX-TRAN 702 after preparing a test piece with a thickness of 500 μm in accordance with ASTM D3985.

6. The biodegradable polyester resin according to claim 5, wherein the processability reduction index (PRI) represented by the following formula 2 is 100 or less: [Formula 2] Processability reduction index (PRI)=Ra + Hz In the formula 2, Ra and Hz are numerical values excluding the units measured on a biodegradable polyester sheet test piece manufactured from the biodegradable polyester resin, the Ra is the center line average roughness (Ra) (nm) calculated by measuring the two-dimensional surface roughness at five or more locations on the surface of the test piece using a surface roughness meter after preparing the test piece by cutting it to a length of 3 cm and a width of 3 cm according to JIS B0601 standard, The Hz is the haze (%) measured using a haze meter after preparing a test piece by cutting to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to the ASTM D1003 standard.

7. The biodegradable polyester resin has an intrinsic viscosity of 5000 poise or more, The biodegradable polyester resin according to claim 5, satisfying at least one characteristic selected from the following physical properties measured with a biodegradable polyester sheet produced from the biodegradable polyester resin: A center line average roughness (Ra) of 50 nm or less, A haze (Hz) of 50% or less, A coefficient of static friction (FC) of 5 or less, 800 CC / m ２ ・ oxygen permeability (OP) of less than day atm, and A tensile strength (TS) of 35 MPa or more.

8. The biodegradable polyester resin contains an aliphatic polyester resin or an aliphatic-aromatic polyester resin, The aliphatic polyester resin contains polylactic acid (PLA), The biodegradable polyester resin according to claim 5, wherein the aliphatic-aromatic polyester resin contains a first repeating unit containing a first diol residue and an aromatic dicarboxylic acid residue, and a second repeating unit containing a second diol residue and an aliphatic dicarboxylic acid residue.

9. The biodegradable polyester resin according to claim 5, further containing nanocellulose having an average particle size of 100 nm or more.

10. When the filter pressure of the biodegradable polyester resin is measured with an extruder equipped with a single screw and a 40 μm mat filter, the difference (ΔFP) in filter pressure represented by the following formula 3 is 100 kg / cm ２ The biodegradable polyester resin according to claim 5, wherein the following holds: [Formula 3] ΔFP = │FP ０ - FP ２ │ In the formula 3, FP ０ is the initial pressure (kg / cm ２ ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C, FP ２ is the pressure (kg / cm ２ ) applied to the filter when the biodegradable polyester resin is extruded at 240 °C for 2 hours.

11. including the step of subjecting the biodegradable polyester polymerization composition of claim 1 to a polycondensation reaction at least once or more, the content of metal in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the total weight, A method for producing a biodegradable polyester resin, wherein the dispersion index (DI) represented by the following formula 1 is 3.0 or more: [Formula 1] In the formula 1, TS and OP are numerical values excluding the units measured with a biodegradable polyester sheet test piece produced from the biodegradable polyester resin, The TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing a test piece according to the ASTM D638 Type V standard, The OP was the oxygen permeability (CC / m ２ ·day·atm) measured at a temperature of 25 °C and a relative humidity (RH) of 0% after preparing a test piece with a thickness of 500 μm in accordance with ASTM D3985 using an OX-TRAN 702.

12. The biodegradable polyester polymerization composition is ring-opening polymerizing a lactide monomer, or esterifying at least once or more using a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component to produce a prepolymer, The method for producing a biodegradable polyester resin according to claim 11, comprising the step of mixing the prepolymer and the inorganic filler.

13. Comprising a biodegradable polyester resin, The biodegradable polyester resin is A biodegradable polyester resin formed from the biodegradable polyester polymerization composition of claim 1, The content of metal in the biodegradable polyester resin is 0.01% by weight to 7% by weight based on the total weight, A biodegradable polyester film having a dispersion index (DI) represented by the following formula 1 of 3.0 or more: [Formula 1] In the formula 1, TS and OP are numerical values excluding the units measured on a biodegradable polyester sheet test piece produced from the biodegradable polyester resin, The TS is the tensile strength (MPa) measured at a tensile speed of 100 mm / min using a universal testing machine after preparing a test piece according to ASTM D638 Type V standard. The OP was the oxygen permeability (CC / m ２ ·day·atm) measured at a temperature of 25°C and a relative humidity (RH) of 0% using an OX-TRAN 702 after preparing a test piece with a thickness of 500 μm in accordance with ASTM D3985.

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