Biodegradable polyester polymerizable 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] Examples of implementations are: Biodegradable polyester polymerizable composition This invention relates to 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 to the disposal problems of various everyday products, especially disposable products, are being sought. Specifically, commonly used polymer materials have the drawback of releasing harmful substances when incinerated, and some types take hundreds of years to decompose completely in nature.

[0003] To overcome the limitations of such polymers, research is actively being conducted on biodegradable polymers that decompose more rapidly. Examples of such biodegradable polymers include polybutylene adipate terephthalate (PBAT), polybutylenesuccinate (PBS), polybutylene adipate (PBA), and polycaprolactone (PCL).

[0004] However, because the biodegradable polymer has a viscosity more than twice 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, leading to a rapid decrease in molecular weight and a deterioration in mechanical properties.

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

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

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 is to provide a [substance] that can improve dispersibility during the polymerization (condensation polymerization) process. Biodegradable polyester polymerizable composition

[0010] Another implementation example is 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 variously utilized for packaging.

[0011] ​ Another example of implementation is to provide a method for producing the biodegradable polyester resin that prevents filter clogging during melt extrusion, minimizes void generation during processing, improves processability, productivity, and moldability, and achieves the aforementioned properties in an economical and efficient manner.

[0012] Another example of implementation has the aforementioned excellent characteristics Biodegradable polyester polymerizable composition Alternatively, by using biodegradable polyester resin, we aim to provide biodegradable polyester films and environmentally friendly packaging materials that are biodegradable, environmentally friendly, and possess excellent mechanical strength, transparency, and oxygen barrier properties. [Means for solving the problem]

[0013] One example of implementation is aliphatic polyester polymerization. sex Composition or aliphatic-aromatic polyester polymerization sex The composition includes an inorganic filler. Biodegradable polyester polymerizable composition and the aliphatic polyester polymerization sex The composition is selected from the group consisting of lactide monomers and their ring-opening prepolymers, and the aliphatic-aromatic polyester polymerization sex The 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, and the inorganic filler is the Biodegradable polyester polymerizable composition It is included in an amount of 0.1% to 10% by weight based on the total weight, and the above Biodegradable polyester polymerizable composition It has a viscosity of 5000 to 15000 poise at 240°C. Biodegradable polyester polymerizable composition To provide.

[0014] Other examples of implementation are as follows: Biodegradable polyester polymerizable composition The present invention provides a biodegradable polyester resin formed by the above, wherein the metal content in the biodegradable polyester resin is 0.01% to 7% by weight based on the total weight, and the dispersion index (DI) represented by the following formula 1 is 3.0 or higher.

[0015] [Formula 1] JPEG0007911090000001.jpg1569 In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test specimens made from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m²) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). 2 (day·atm)

[0016] Other examples of implementation are as follows: Biodegradable polyester polymerizable composition The present invention provides a method for producing a biodegradable polyester resin, comprising the step of carrying out a condensation polymerization reaction at least once, wherein the metal content in the biodegradable polyester resin is 0.01% to 7% by weight based on the total weight, and the dispersion index (DI) represented by formula 1 is 3.0 or higher.

[0017] Another example of implementation includes the biodegradable polyester resin, wherein the biodegradable polyester resin is the Biodegradable polyester polymerizable composition The present invention provides a biodegradable polyester film formed by the above, wherein the metal content in the biodegradable polyester resin is 0.01% to 7% by weight based on the total weight, and the dispersion index (DI) represented by formula 1 is 3.0 or higher. [Effects of the Invention]

[0018] Examples of implementation Biodegradable polyester polymerizable composition This material contains inorganic fillers in a specific amount and satisfies a specific viscosity range, resulting in excellent dispersibility during the polymerization (condensation polymerization) process. Biodegradable polyester polymerizable composition The metal content and dispersion index in the biodegradable polyester resin produced by this method can be adjusted to an optimal range.

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

[0020] Furthermore, the method for producing biodegradable polyester resin according to the realization example includes the inorganic filler. Biodegradable polyester polymerizable composition By using this method to carry out the condensation polymerization reaction, the dispersibility during the condensation polymerization reaction is excellent, and the aggregation of inorganic filler particles can be suppressed. This prevents filter clogging, reduces the occurrence of defects such as voids in the processing step, and simultaneously improves moldability, processability, and productivity, thereby providing biodegradable films and molded products of superior quality. [Modes for carrying out the invention]

[0021] The invention will be described in detail below with reference to examples of its implementation. The examples of implementation are not limited to those disclosed below and can be modified in various forms as long as the gist of the invention is not altered.

[0022] In this specification, when a part is said to "include" a component, unless otherwise stated, this means that it may include other components rather than excluding them.

[0023] Furthermore, all numerical ranges indicating physical properties, dimensions, etc., of the components described herein should be understood to be modified by the term "approximately" in all cases, unless otherwise specified.

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

[0025] In one implementation example, the inorganic filler is included in a specific content. Biodegradable polyester polymerizable composition By polymerizing and condensing the material to produce a biodegradable polyester resin, the metal content and dispersion index (DI) within the biodegradable polyester resin can be made to satisfy a specific range. This further improves transparency, reduces void formation during processing, and improves oxygen barrier properties by lowering oxygen permeability while increasing tensile strength, thus enabling diverse applications as a packaging material. Furthermore, since excellent dispersibility can be achieved without the use of dispersants, there is technical significance in that it enables the creation of a high-quality, environmentally friendly packaging material that is biodegradable and exhibits excellent properties through an economical and efficient method.

[0026] [ Biodegradable polyester polymerizable composition ] One example Biodegradable polyester polymerizable composition This is aliphatic polyester polymerization. sex Composition or aliphatic-aromatic polyester polymerization sex The composition comprises an inorganic filler, wherein the aliphatic polyester polymerizable composition is selected from the group consisting of lactide monomers and their ring-opening prepolymers, and the aliphatic-aromatic polyester polymerizable composition comprises one or more selected from the group, and the aliphatic-aromatic polyester polymerizable composition comprises one or more selected from the group, and the aliphatic-aromatic polyester polymerizable composition comprises one or more selected from the group consisting of lactide monomers and their ring-opening prepolymers, and the aliphatic-aromatic polyester polymerizable composition comprises one or more selected from the group, and the aliphatic-aromatic polyester polymerizable composition comprises one inorganic filler, and the alipha sex The 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, and the inorganic filler is the Biodegradable polyester polymerizable composition It is included in an amount of 0.1% to 10% by weight based on the total weight, and the above Biodegradable polyester polymerizable composition It has a viscosity of 5,000 to 15,000 poise at 240°C.

[0027] Specifically, the above Biodegradable polyester polymerizable composition This is aliphatic polyester polymerization. sex Composition or aliphatic-aromatic polyester polymerization sex It may contain the following composition.

[0028] The aliphatic polyester polymerization sex The composition may be selected from 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 sex The composition may be 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.

[0031] For example, the aliphatic-aromatic polyester polymerization sex group The product may include a prepolymer obtained by mixing a diol component and an aromatic dicarboxylic acid component to obtain a slurry, and then performing at least one esterification reaction using a mixture containing the slurry and an aliphatic dicarboxylic acid component, or a mixture containing the reaction product obtained by esterifying the slurry and an aliphatic dicarboxylic acid component.

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

[0033] The aforementioned 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 derivatives thereof.

[0035] On the other hand, Biodegradable polyester polymerizable composition The inorganic filler is the aforementioned Biodegradable polyester polymerizable composition It may be included in an amount of 0.1% to 10% by weight based on the total weight.

[0036] Generally, inorganic fillers are used to improve slip properties during processing. However, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene adipate (PBA), and polycaprolactone (PCL), which are widely used as biodegradable polymers, have high viscosity with a number-average molecular weight of at least 40,000. Therefore, adding inorganic fillers during the polymerization process may slow down or prevent the reaction from proceeding at all.

[0037] On the other hand, when compounding (blending) inorganic fillers with biodegradable polyester resin, not only is a large amount of inorganic filler required to achieve the aforementioned effect, but the poor compatibility between biodegradable polyester resin and inorganic filler can lead to void formation during the blowing process and / or extrusion stretching, causing bubbles to burst or break, resulting in reduced productivity and problems that act as internal and surface defects in the film.

[0038] Therefore, in order to achieve optimal dispersibility and efficiently achieve the desired effect, the present invention solves the aforementioned problems by adjusting the content of the inorganic filler and controlling the specific surface area and particle size range of the inorganic filler, the pretreatment process, and the timing of addition, thereby improving dispersibility during the polymerization process. Biodegradable polyester polymerizable composition By controlling the metal content and dispersion index within the biodegradable polyester resin produced by this method to an optimal range, the overall surface roughness, haze, static friction coefficient, oxygen permeability, and tensile strength of the biodegradable polyester sheet or film can be improved.

[0039] Specifically, the above Biodegradable polyester polymerizable composition The inorganic filler is the Biodegradable polyester polymerizable composition Based on the total weight, it may contain, for example, 0.1% to 10% by weight, 0.5% to 9% by weight, 1% to 9% by weight, 1% to 8% by weight, 1% to 6% by weight, 1% to 5% by weight, 2% to 5% by weight, 3% to 5% by weight, or 4% to 6% by weight.

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

[0041] When the content of the inorganic filler is less than the above range, it is difficult to achieve the effects intended in the present invention. When 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 contain one or more selected from the group consisting of SiO2, CaCO3, TiO2, BaSO4, and Al2O3. Specifically, the inorganic filler may contain one or more selected from the group consisting of SiO2, CaCO3, and TiO2. Inclusion of the inorganic filler may be more advantageous for improving slip properties during processing.

[0043] On the other hand, according to one embodiment 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 more 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 m2 / g or more, 50m 2 / g, 55m 2 / g or more, 60m 2 / g or more, 70m 2 / g or more, 80m 2 / g or more, or 100m 2 It may be greater than or equal to / g. The specific surface area can be measured, for example, using a BET specific surface area analyzer (ASAP 2020, Micromeritics).

[0045] If the specific surface area of ​​the inorganic filler satisfies the aforementioned range, it is possible to prevent the inorganic filler particles from aggregating, which is advantageous for adjusting the metal content and dispersion index in the biodegradable polyester resin targeted by 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 aforementioned range, the inorganic filler particles are prone to aggregating as secondary particles, and even if dispersed, they tend to lose stability and re-aggregate.

[0046] Furthermore, 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. Also, 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 refers to the particle size or median diameter measured when the cumulative volume reaches 50%, and can be measured using a particle size analyzer Microtrac S3500 in particle size distribution (PSD). When the average particle size (D50) of the inorganic filler satisfies the aforementioned range, aggregation of the inorganic filler particles can be prevented, which is advantageous for adjusting the metal content and dispersion index in the biodegradable polyester resin targeted by the present invention to an optimal range, and can further improve the surface roughness and mechanical strength of the biodegradable polyester sheet.

[0047] The inorganic filler may be an inorganic filler that has been pretreated by one or more methods selected from ultrasonic treatment, a mixer tank, a high-pressure homogenizer, and pretreatment with a dispersant.

[0048] Pre-treating the inorganic packing material by the method described above makes dispersion easier during the polymerization condensation stage. In particular, agglomeration does not occur during transfer between reactors, thus preventing filter clogging and offering the advantage of achieving excellent dispersibility without the need for dispersant addition.

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

[0050] The ultrasonic treatment may be performed with an energy amount of 50,000 J or less for a time of less than 30 minutes. For example, the ultrasonic treatment may 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 for the energy amount and the execution time, the effect of the ultrasonic treatment, i.e., the improvement of dispersibility, can be maximized. If the energy amount exceeds the above range, the particles of the inorganic filler may re-aggregate, and the dispersibility may decrease. Also, if the particles of the inorganic filler aggregate or re-aggregate, Biodegradable polyester polymerizable composition This can cause uneven surface roughness in biodegradable polyester sheets or films manufactured by this method, leading to increased scattering of light when it passes through and reducing transparency.

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

[0052] The pretreatment using the high-pressure homogenizer described above is a mechanical pretreatment method in which a high-pressure fluid is passed at high speed through a small gap in an interaction chamber. At this time, the fluid is subjected to a supersonic flow velocity due to the rapid drop in pressure, and impact, cavitation, turbulence, and shear forces act on the particles in the fluid, causing the inorganic filler to break down into uniform fine particles and become homogeneous. The pretreatment method using the high-pressure homogenizer can be carried out under pressure conditions of 5,000 to 40,000 psi.

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

[0054] Furthermore, when adding the inorganic filler, additional diol components (third diol components) may be added in combination to improve dispersibility and reactivity.

[0055] According to one embodiment of the present invention, the inorganic filler is included Biodegradable polyester polymerizable composition By using this method to perform condensation polymerization and produce biodegradable polyester resin, dispersibility can be further improved compared to compounding (blending) the polyester resin with an inorganic filler, void formation can be reduced and bubble stability during processing can be improved, elongation and tensile strength can be improved, and filter clogging can be minimized, thus further improving productivity, processability and moldability.

[0056] The aforementioned Biodegradable polyester polymerizable composition The viscosity at 240°C may be, for example, 5000 poise or more, 6000 poise or more, 6500 poise or more, 7000 poise or more, or 8000 poise or more. Biodegradable polyester polymerizable compositionThe viscosity may be, for example, 15,000 poise or less, 13,000 poise or less, 12,000 poise or less, 11,000 poise or less, or 10,000 poise or less. Specifically, the above Biodegradable polyester polymerizable composition The viscosity can be, for example, 6000-13000 poise, 7000-13000 poise, 6000-12000 poise, 6000-11000 poise, or 6000-10000 poise.

[0057] The aforementioned Biodegradable polyester polymerizable composition When the viscosity satisfies the above range, it can further improve dispersibility during the polymerization reaction, thereby improving the mechanical strength of the biodegradable resin, as well as reducing the surface roughness, haze, static friction coefficient, and oxygen permeability of the biodegradable polyester sheet or film, which may be even more advantageous in achieving optimal levels of composite physical properties such as the dispersion index (DI) and processability reduction index (PRI). The viscosity is measured immediately after the inorganic filler is added. Biodegradable polyester polymerizable composition The viscosity was measured using a dynamic viscometer, RDS (Rheometrics Dynamic Spectrometer, Discovery HR30, TA Instrument Co.), at a temperature of 240°C while increasing the angular velocity per second (1 rad / sec) (1 rad / sec = 9.5 rpm). The viscosity may vary depending on the shear rate.

[0058] On the other hand, the present invention, as demonstrated by the examples, Biodegradable polyester polymerizable composition A biodegradable polyester masterbatch can be provided using this method.

[0059] The biodegradable polyester masterbatch is the Biodegradable polyester polymerizable composition It can be manufactured by conventional methods using [the specified method].

[0060] By polymerizing in situ using the aforementioned biodegradable polyester masterbatch, dispersibility can be further improved, the occurrence of defects such as voids during processing can be reduced, tensile strength can be further increased, and oxygen permeability can be lowered, making it possible to provide a biodegradable film with excellent properties for packaging.

[0061] [Biodegradable polyester resin] The biodegradable polyester resin according to one example is the aforementioned Biodegradable polyester polymerizable composition A biodegradable polyester resin formed by the above, wherein the metal content in the biodegradable polyester resin is 0.01% to 7% by weight based on the total weight, and the variance index (DI) represented by the following formula 1 is 3.0 or higher.

[0062] [Formula 1] JPEG0007911090000002.jpg1569 In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test specimens made from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m²) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). 2 (day·atm)

[0063] The aforementioned Biodegradable polyester polymerizable composition By using this method, the metal content in the biodegradable polyester resin can be satisfied within a specific range, thereby improving the overall physical properties of the biodegradable polyester sheet or film, such as surface roughness, haze, static friction coefficient, oxygen permeability, and tensile strength, and enabling the achievement of optimal levels for composite physical properties such as the dispersion index (DI) and processability reduction index (PRI).

[0064] For example, the metal content in the biodegradable polyester resin is Biodegradable polyester polymerizable compositionBased on the total weight, the metal content 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, greater 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. Furthermore, the metal content in the biodegradable polyester resin is as described above. Biodegradable polyester polymerizable composition Based on the total weight, for example, it could be 0.015% to 6.8% by weight, greater than 0.015% to 6.8% by weight, 0.02% to 6.8% by weight, 0.03% to 6.8% by weight, 0.05% to 6.8% by weight, 0.06% to 6.8% by weight, 0.06% to 6.5% by weight, 0.06% to 6% by weight, 0.06% to 5% by weight, 0.1% to 4% by weight, or 0.1% to 3% by weight.

[0065] The metal content in the biodegradable polyester resin is as follows: Biodegradable polyester polymerizable composition This can vary depending on the amount of inorganic filler contained in the product.

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

[0067] If the metal content in the biodegradable polyester resin is below the range, there is a problem of reduced processing slip, and if the metal content exceeds the range, problems such as re-aggregation and protrusion formation may occur.

[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. Including the metal may be even more advantageous in improving slip properties during processing.

[0069] On the other hand, the content of residual inorganic substances contained in the biodegradable polyester resin may be 0.02% to 8% by weight. Specifically, the content of residual inorganic substances contained in the biodegradable polyester resin may 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 matter is a residue of the inorganic filler 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] Furthermore, the biodegradable polyester resin may have a dispersion index (DI) of 3.0 or higher, as represented by Formula 1.

[0072] The dispersion index (DI) is expressed as 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 inorganic filler particles were properly dispersed during the polymerization process in the production of the biodegradable resin, and at the same time, it may indicate the degree of dispersion of metal and / or residual inorganic particles present in the biodegradable polyester resin formed from the inorganic filler. Furthermore, this may change the oxygen permeability (OP) and tensile strength of the biodegradable polyester sheet or film produced from the biodegradable polyester resin.

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

[0074] In other words, a low oxygen permeability (OP) or high tensile strength of the biodegradable polyester sheet means that the inorganic filler particles were properly dispersed during the polymerization process in the production of the biodegradable resin, and that the metal and / or residual inorganic particles present in the biodegradable polyester resin were uniformly dispersed.

[0075] The aforementioned variance index (DI) may be, for example, 3.2 or higher, 3.5 or higher, 4.0 or higher, 4.2 or higher, 4.3 or higher, 4.5 or higher, 4.6 or higher, or 5.0 or higher. Alternatively, the aforementioned variance index (DI) may be, for example, 15.0 or lower, 12.0 or lower, 11.0 or lower, 10.0 or lower, 9.5 or lower, 9.0 or lower, or 8.0 or lower.

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

[0077] According to one embodiment of the present invention, the oxygen permeability (OP) of a biodegradable polyester sheet made from the biodegradable polyester resin is, for example, 800 CC / m². 2 ·day · atm or less, 10~800CC / 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 It could be a day ATM.

[0078] If the oxygen permeability (OP) of the biodegradable polyester sheet satisfies the above range, it exhibits excellent oxygen barrier properties and may be even more advantageous for use as a packaging material, particularly for food packaging. If the oxygen permeability (OP) of the biodegradable polyester sheet is 800 CC / m²2 If the oxygen barrier properties exceed 1 / day·atm, it can lead to various problems when used as packaging material.

[0079] According to one embodiment of the present invention, the tensile strength (TS) of a biodegradable polyester sheet manufactured from the biodegradable polyester resin may 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 aforementioned range, it is more advantageous to achieve the dispersion index (DI) within the specified range, and because the range of 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) of 100 or less, as shown in the following formula 2.

[0082] [Formula 2] Processability Reduction Index (PRI) = Ra + Hz In the above formula 2, Ra and Hz are numerical values ​​obtained by excluding the units measured on a biodegradable polyester sheet test piece made from the biodegradable polyester resin, The aforementioned Ra is the centerline average roughness (Ra) (nm) calculated by preparing a test specimen by cutting it 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 locations on the surface of the test specimen using a surface roughness meter. The aforementioned Hz is the haze (%) measured using a haze analyzer after preparing test specimens by cutting them to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to ASTM D1003 standards.

[0083] The processability reduction index (PRI) of the biodegradable polyester resin is expressed as the sum of the centerline mean roughness (Ra) and haze of the biodegradable polyester sheet produced from the biodegradable polyester resin. In other words, the centerline mean roughness (Ra) and haze (Hz) of the biodegradable polyester sheet vary depending on the degree of aggregation of inorganic filler particles in the biodegradable polyester resin, which can significantly affect processability. Furthermore, aggregation of the inorganic filler particles can make the surface roughness of the biodegradable polyester sheet or film uneven, causing increased scattering when light is transmitted, reducing the transparency of the biodegradable polyester sheet or film, and potentially leading to problems such as the precipitation of the inorganic filler particles or their remaining as internal defects.

[0084] The processability reduction index (PRI) of the biodegradable polyester resin may decrease as the mean centerline roughness (Ra) of the biodegradable polyester sheet decreases, or as the haze (Hz) decreases. Furthermore, a lower PRI value of the biodegradable polyester resin may be even more advantageous in providing a biodegradable film with superior properties 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 process, has excellent slip properties, can further reduce the occurrence of defects inside or on the surface of the biodegradable film, and can be advantageous in providing high-quality packaging materials.

[0086] The centerline average roughness (Ra) of a biodegradable polyester sheet manufactured from the aforementioned biodegradable polyester resin can be calculated by preparing test specimens by cutting them to a length of 3 cm and a width of 3 cm according to JIS B0601 standards, and then measuring the two-dimensional surface roughness at five or more locations on the surface of the test specimens using a surface roughness meter. This can be measured using an AFM device (e.g., XE-150, Park Systems). For example, the centerline average roughness (Ra) is the arithmetic mean roughness of the deviations of the roughness curve relative to the average line according to JIS 0161, and is expressed as the sum of the deviations above and below the centerline of a reference length, divided by the length of the measurement interval.

[0087] The centerline 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 between 10 nm and 50 nm.

[0088] If the centerline mean roughness (Ra) of the biodegradable polyester sheet satisfies the above range, it may be even more advantageous in achieving the effects targeted by the present invention. If the centerline mean roughness (Ra) of the biodegradable polyester sheet exceeds 50 nm, the surface roughness becomes non-uniform, which can cause more scattering when light is transmitted, thereby reducing the transparency of the biodegradable polyester sheet or film.

[0089] In yet another embodiment of the present invention, the haze of the biodegradable polyester sheet produced from the biodegradable polyester resin is low, at 50% or less, which provides excellent transparency and the advantage of being able to be used in a variety of applications requiring transparency.

[0090] Specifically, the haze of the biodegradable film may 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, limiting its applications.

[0091] On the other hand, according to the present invention and other embodiments, the static friction coefficient of the biodegradable polyester sheet manufactured from the biodegradable polyester resin is 5 or less, and may be, 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 using a friction coefficient tester (QM110CF, QMESYS) in accordance with ASTM D1894, by measuring the static friction coefficient when one surface of the biodegradable polyester sheet is brought into contact with stainless steel (SUS) and slides.

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

[0093] When the viscosity of the biodegradable polyester resin satisfies the aforementioned range, the occurrence of defects such as voids during the processing step can be reduced, further improving processability, productivity, and moldability. In addition to excellent mechanical properties, it is possible to provide a biodegradable film with reduced oxygen permeability and superior properties for packaging.

[0094] Furthermore, the number-average molecular weight of the biodegradable polyester resin may be between 30,000 g / mol and 100,000 g / mol, between 40,000 g / mol and 90,000 g / mol, or between 40,000 g / mol and 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, and the molecular weight can be measured using the number-average molecular weight (Mn) as the reference. By satisfying the above range for 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 of the biodegradable polyester resin is measured in an extruder equipped with a single screw and a 40 μm mat filter, the filter pressure difference (ΔFP) expressed in the following formula 3 is 100 kg / cm². 2 The following are possible:

[0096] [Formula 3] ΔFP = │FP0 - FP2│ In the above formula 3, FP0 is the initial pressure (kg / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C. 2 ) and FP2 is the pressure (kg / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C for 2 hours. 2 )

[0097] The aforementioned filter pressure difference (ΔFP) is the initial pressure (kg / cm²) applied to the filter when it is extruded at 240°C. 2 ) and the pressure (kg / cm²) applied to the filter when extruded at the same temperature for 2 hours. 2 This is the absolute value of the difference between ( ) and represents the change in filter pressure.

[0098] During the condensation polymerization reaction of the biodegradable polyester resin, if the inorganic filler particles are well dispersed, the filter pressure difference (ΔFP) is small. However, if the inorganic filler particles are not well dispersed, aggregation can occur, clogging the filter and potentially causing an increase in filter pressure or even filter rupture, which can lead to problems with productivity, processability, and moldability. Therefore, it is extremely important to control the filter pressure difference (ΔFP) to be below a specific range.

[0099] For example, the filter pressure difference (ΔFP) is 90 kg / cm². 2 Below 85kg / cm 2 Below 80kg / cm 2 Below 70kg / cm 2 Below 60kg / cm 2 Below 50kg / cm 2 Below, 40kg / cm 2 Below 30kg / cm 2 Below, or 20 kg / cm³ 2 The following may apply, and within the above range, a smaller difference in filter pressure (ΔFP) may be more advantageous in terms of productivity, processability, and moldability.

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

[0101] The polylactic acid resin may contain 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. In this case, the content of D-lactic acid may be, for example, 1% to 5% by weight, 1% to 4% by weight, 2% to 4% by weight, 1% to 2% by weight, or 2% to 3% by weight, based on the total weight of the polylactic acid resin. If the content of D-lactic acid satisfies the above range, it may be advantageous in terms of improving the stretchability of the film.

[0103] The L-lactic acid content may be, for example, 80% to 99% by weight, 83% to 99% by weight, 85% to 99% by weight, 95% to 99% by weight, 96% to 99% by weight, 96% to 98% by weight, or 96% to 97% by weight, based on the total weight of the polylactic acid resin. Satisfying the above range for the L-lactic acid content may be advantageous in terms of improving the heat resistance properties 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 aforementioned polylactic acid resin has a melt viscosity (V) at 210°C. PLA The melt viscosity can be, 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] A biodegradable polyester resin according to one embodiment of the present invention may comprise a first repeating unit comprising a first diol residue and an aromatic dicarboxylic acid residue, and a second repeating unit comprising a second diol residue and an aliphatic dicarboxylic acid residue.

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

[0109] The biodegradable polyester resin having the above structure can improve the biodegradability, water degradability, and physical properties of biodegradable polyester sheets, films, or molded articles obtained using it.

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

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

[0112] When the number of the first repeating units and the number of the second repeating units each satisfy the above range, the desired molecular weight of the biodegradable polyester resin can be achieved, improving processability and physical properties, and further enhancing the mechanical properties, heat resistance, and biodegradability of biodegradable polyester sheets, films, or molded articles manufactured using it. If the number of the first repeating units and / or the second repeating units is too small, the molecular weight of the biodegradable polyester resin will also be small, making it 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, 100nm to 500nm, 100nm to 450nm, 120nm to 400nm, 130nm to 350nm, 140nm to 300nm, or 150nm to 300nm.

[0115] By ensuring that the average particle size of the nanocellulose satisfies the aforementioned range, the biodegradability and physical properties of the biodegradable polyester resin, or the biodegradable polyester sheets, films, and molded articles obtained using it, can be further improved.

[0116] The nanocellulose may be one or more selected from the group consisting of cellulose nanocrystals, cellulose nanofibers, microfibrillated cellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, cellulose acetate, methylcellulose, ethylcellulose, propylcellulose, butylcellulose, pentylcellulose, hexylcellulose, and cyclohexylcellulose.

[0117] Furthermore, the nanocellulose may be pre-treated with a bead mill or ultrasonically. Specifically, the nanocellulose may be water-dispersed nanocellulose that has been pre-treated with a bead mill or ultrasonically.

[0118] First, the pretreatment of the bead mill can be performed using a wet milling apparatus, either a vertical mill or a horizontal mill. A horizontal mill is preferred because it can fill the chamber with a larger quantity of beads, reduces uneven wear on the machine, reduces bead wear, and makes maintenance easier, but it is not limited to this.

[0119] The bead mill pretreatment may be carried out using one or more beads selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide.

[0120] Specifically, the bead mill pretreatment may be performed using beads having a diameter of 0.3 mm to 1 mm. For example, the diameter of the beads may 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 for 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] Furthermore, the bead mill pretreatment is preferable in that it uses beads with a specific gravity higher than that of nanocellulose, in order to transfer sufficient energy. For example, the beads may be one or more selected from the group consisting of zirconium, zircon, zirconia, quartz, and aluminum oxide, which have a specific gravity higher than that of water-dispersed nanocellulose. Zirconium beads with a specific gravity four times or more higher than that of water-dispersed nanocellulose are preferred, but the method is not limited thereto.

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

[0123] The ultrasonic pretreatment may be performed with an energy level of 30,000 J or less for a period of less than 30 minutes. For example, the ultrasonic pretreatment may be performed with an energy level of 25,000 J or less or 22,000 J or less for a period of 25 minutes or less, 20 minutes or less, or 18 minutes or less. By satisfying the above ranges for energy level and duration, the effect of the ultrasonic pretreatment, i.e., the improvement of dispersibility, can be maximized. If the energy level exceeds the above range, the nanoparticles may re-aggregate, leading to a decrease in dispersibility.

[0124] The nanocellulose in the realization example may have undergone bead mill pretreatment or ultrasonic pretreatment. Alternatively, the nanocellulose in the realization example may have undergone both bead mill pretreatment and ultrasonic pretreatment. In this case, it is preferable to perform ultrasonic pretreatment after bead mill pretreatment in order to prevent re-aggregation and improve dispersibility.

[0125] The polydispersity index (PDI) of the biodegradable polyester resin in the implemented examples 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 aforementioned range, the heat resistance can be further improved. Specifically, if the polydispersity index exceeds the aforementioned range, the heat resistance of the biodegradable polyester resin may decrease. As a result, in the process of manufacturing molded products such as films using the biodegradable polyester resin, the incidence of polymer degradation may increase, leading to a decrease in processability and productivity.

[0127] The aforementioned multivariance index can be calculated using the following formula A.

[0128] [Formula A] JPEG0007911090000003.jpg1253 In 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] The present invention, by one implementation example, Biodegradable polyester polymerizable composition A method for producing a biodegradable polyester resin can be provided, comprising the step of carrying out a condensation polymerization reaction at least once, wherein the metal content in the biodegradable polyester resin is 0.01% to 7% by weight based on the total weight, and the dispersion index (DI) represented by the above formula 1 is 3.0 or higher.

[0130] According to one embodiment of the present invention, the inorganic filler is included in a specific content. Biodegradable polyester polymerizable composition By using this method to carry out a condensation polymerization reaction, it is possible to provide a biodegradable film with excellent properties for packaging, which is biodegradable, reduces the occurrence of defects such as voids during processing, further increases tensile strength, and lowers oxygen permeability, all through a simple, economical, and efficient manufacturing process. Furthermore, in terms of the process, it is possible to minimize the phenomenon of filter clogging during processing and reduce the difference between the initial and final filter pressures, thereby improving productivity and processability, and solving problems such as bubble bursting and rupture.

[0131] Specifically, the method for producing the biodegradable polyester resin comprises a first step of producing a prepolymer by ring-opening polymerization of a lactide monomer or by esterifying it at least once using a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component, and a second step of mixing the prepolymer with an inorganic filler. Biodegradable polyester polymerizable composition The second step to obtain the above Biodegradable polyester polymerizable composition This may include a third step of carrying out a condensation polymerization 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 performing an esterification reaction at least once using a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component.

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

[0134] In the first step, the step of carrying out an esterification reaction at least once using the diol component, aromatic dicarboxylic acid component, and aliphatic dicarboxylic acid component may include the steps of mixing the diol component and aromatic dicarboxylic acid to obtain a slurry, and carrying out an esterification reaction at least once using a mixture containing the slurry and aliphatic dicarboxylic acid, or a mixture containing the reaction product obtained by esterifying the slurry and aliphatic dicarboxylic acid.

[0135] By mixing the diol component with 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 rapidly advancing the esterification reaction, thereby increasing the reaction efficiency.

[0136] In particular, when aromatic dicarboxylic acids, such as terephthalic acid, are perfectly crystalline and in powder form, their solubility in the diol is very low, which can make homogeneous reactions difficult. Therefore, the slurrying step can play a very important role in providing biodegradable polyester resins, sheets, films, and molded articles with excellent physical properties as demonstrated in the embodiment of the present invention, and in increasing reaction efficiency.

[0137] Furthermore, if the diol component and aromatic dicarboxylic acid are not mixed to form a slurry, and the esterification reaction is carried out by mixing all of them together, the reaction of the diol component and the aliphatic dicarboxylic acid may proceed first, making it difficult to achieve the effects intended in this invention.

[0138] In an embodiment of the present invention, when the aromatic dicarboxylic acid component is terephthalic acid, the terephthalic acid is perfectly crystalline, has no melting point, is a white crystal that sublimes at atmospheric pressure and a temperature of about 300°C, and has very low solubility in the diol component. Therefore, homogeneous reactions are unlikely to occur. By performing a slurrying step before the esterification reaction, the surface area for reaction with the diol component within the solid matrix of terephthalic acid can be increased, thereby inducing a homogeneous reaction.

[0139] Furthermore, in the embodiment of the present invention, when the aromatic dicarboxylic acid component is dimethyl terephthalate, the slurrying step allows the dimethyl terephthalate to be melted at approximately 142°C to 170°C and reacted with the diol, thereby enabling the esterification reaction to proceed more rapidly and efficiently.

[0140] Furthermore, during the slurrying stage, 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 includes terephthalic acid, and the terephthalic acid has an average particle size (D50) of 400 μm or less, measured by a Microtrac S3500 particle size analyzer, in its particle size distribution (PSD), for example, 10 μm to 400 μm, and a standard deviation of 100 or less relative to the average particle size (D50). The standard deviation refers to the square root of the variance.

[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. If the average particle size (D50) of the terephthalic acid satisfies the above range, it may be even more advantageous in terms of improved solubility and reaction rate in relation to the diol component.

[0143] If the average particle size (D50) of terephthalic acid is less than 10 μm, it is undesirable because the average particle size is too small and can be converted from single primary particles to aggregated secondary particles. If the average particle size (D50) of terephthalic acid exceeds 400 μm, the average particle size is too large, which can reduce its solubility in the diol, slow down the reaction rate, and make it difficult to obtain a homogenization reaction.

[0144] Furthermore, the standard deviation of the average particle size (D50) of terephthalic acid may be 100 or less, for example, 5-90, 5-80, 5-70, 10-70, 15-70, or 15-50. If the standard deviation of the average particle size (D50) of terephthalic acid satisfies the above range, it may be even more advantageous in terms of improved solubility and reaction rate in relation to the diol component.

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

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

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

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

[0149] The slurry agitator may be even more advantageous in achieving efficient stirring if, for example, its lowest part is of the anchor type, the height to the agitator is 20 mm or more, and it is equipped with two or more rotating blades.

[0150] For example, the slurry agitator may be positioned at a height of 20 mm or more from the agitator, meaning that the reactor and the bottom of the agitator are almost touching. In this case, a slurry without sedimentation can be obtained. If the number, shape, and / or slurrying process conditions of the agitator do not satisfy the above conditions, the aromatic dicarboxylic acid component may settle at the bottom when the diol component and aromatic dicarboxylic acid component are initially mixed, in which case phase separation may occur.

[0151] The slurrying step may include mixing the diol component and the 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 to 200 minutes. If 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 this invention can be obtained efficiently.

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

[0153] Specifically, the diol component may contain 1,4-butanediol, 1,2-ethanediol, 1,3-propanediol, or derivatives thereof in amounts of 95 mol% or more, 98 mol% or more, 99 mol% or more, or 100 mol% based on the total number of moles of the diol component. By including 1,4-butanediol, 1,2-ethanediol, 1,2-ethanediol, 1,3-propanediol, or derivatives thereof within the above ranges, the biodegradability, water degradability, and physical properties of the biodegradable polyester resin or biodegradable polyester sheets, films, or molded articles obtained using it can be improved.

[0154] The diol component may be added all at once or in installments. For example, the diol component may be added separately when mixing with aromatic dicarboxylic acid and when mixing with 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] Furthermore, the aromatic dicarboxylic acid component may be used in amounts 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 aforementioned range is even more advantageous in obtaining the effects of the present invention, and can improve the physical properties, biodegradability, and water decomposition reduction rate of biodegradable polyester sheets, films, or molded articles produced using them.

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

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

[0160] According to one embodiment of the present invention, the esterification reaction can be carried out in a single step by adding an aliphatic dicarboxylic acid component, or a diol component and an aliphatic dicarboxylic acid component, to the slurry.

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

[0162] The number-average molecular weight of the prepolymer can range from 500 g / mol to 10000 g / mol. For example, the number-average molecular weight of the prepolymer can range from 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 satisfying the above range for the number-average molecular weight of the prepolymer, the molecular weight of the polymer can be efficiently increased in the condensation polymerization reaction.

[0163] According to yet another embodiment of the present invention, the esterification reaction may be carried out two or more times, comprising the steps of: first esterifying the slurry; and second esterifying the reaction product obtained from the first esterification reaction by adding an aliphatic dicarboxylic acid, or a diol and an aliphatic dicarboxylic acid.

[0164] Performing the esterification reaction two or more times can improve reaction stability and reaction uniformity compared to performing the esterification reaction once.

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

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

[0167] Furthermore, the aliphatic dicarboxylic acid component may be used in amounts 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 aforementioned range is even more advantageous in obtaining the effects of the present invention, and can further improve the impact resistance and durability of molded articles such as biodegradable polyester sheets, films, or biodegradable polyester injection molded products manufactured using the same.

[0169] In particular, the aliphatic dicarboxylic acid component, being composed of a linear chain, may affect the mechanical properties of the biodegradable polyester resin, as well as its 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 the biodegradable polyester sheet or film produced from the biodegradable polyester resin may deteriorate.

[0171] Nanocellulose may be further added at the esterification reaction stage, for example, at the primary esterification reaction stage, the secondary esterification reaction stage, or both, when primary and secondary esterification reactions are carried out.

[0172] Specifically, when the esterification reaction is carried out in one step, nanocellulose may be added at the time of the esterification reaction, for example, when an aliphatic dicarboxylic acid, or a diol and aliphatic dicarboxylic acid, are added.

[0173] Furthermore, when the esterification reaction is carried out two or more times, nanocellulose can be added at the time of the primary esterification reaction, the secondary esterification reaction, or both. For example, the nanocellulose can be added at the time of the secondary esterification reaction, i.e., at the time of adding the aliphatic dicarboxylic acid, or the diol and aliphatic dicarboxylic acid, or in the early stages of the esterification reaction. This may be efficient for dispersing the nanocellulose. In particular, the addition of nanocellulose is preferable in terms of the mechanical 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 article.

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

[0175] Furthermore, the nanocellulose content 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, based on the total weight of diols, aromatic dicarboxylic acids, and aliphatic dicarboxylic acids, and may be 100 ppm or more, 150 ppm or more, 200 ppm or more, 250 ppm or more, or 300 ppm or more. By satisfying the above range for the nanocellulose content, biodegradability and mechanical properties such as strength can be further improved.

[0176] In the first step described above, the esterification reaction may be initiated after adding a titanium-based catalyst or a germanium-based catalyst.

[0177] Specifically, when performing the esterification reaction in a single step, a mixture containing a diol component, an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid can be prepared, the catalyst can be added, and then the esterification reaction can be carried out.

[0178] Furthermore, when the esterification reaction is carried out two or more times, the catalyst may be added to the reactor before each esterification reaction before initiating the esterification reaction. Specifically, the slurry may be placed in the reactor, the catalyst may be added, and / or, an aliphatic dicarboxylic acid, or a diol component and an aliphatic dicarboxylic acid, may be added to the reaction product obtained by the primary esterification reaction of the slurry, the catalyst may be added, and then the secondary esterification reaction may be carried out.

[0179] Specifically, the biodegradable polyester resin may contain one or more titanium-based catalysts 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 one or more germanium-based catalysts selected from the group consisting of germanium oxide, germanium methoxide, germanium ethoxide, tetramethylgermanium, tetraethylgermanium, and germanium sulfide.

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

[0181] A phosphorus-based stabilizer may be further added during the esterification reaction in the second step, at the end of the esterification reaction, or both.

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

[0183] Furthermore, when the esterification reaction is carried out two or more times, a phosphorus-based stabilizer may be added during the primary esterification reaction, the secondary esterification reaction, or both, or at the end of the primary esterification reaction or the end of the secondary esterification reaction.

[0184] Specifically, the biodegradable polyester resin may further contain an amine-based high-temperature heat stabilizer such as tetraethylenepentaamine, and one or more phosphorus-based stabilizers selected from the group consisting of phosphoric acid, phosphorous acid, polyphosphate, trimethylphosphate, triethylphosphate, 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 satisfying the above range for the content of the phosphorus-based stabilizer, degradation of the polymer due to high temperatures 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 esterification reaction is complete, one or more additives selected from the group consisting of silica, potassium, titanium dioxide, or magnesium, and color correctors such as cobalt acetate may be added. That is, after the esterification reaction is complete, the additives and / or color correctors may be added to stabilize the mixture, and then the polymerization condensation reaction may proceed.

[0187] The method for producing the biodegradable polyester resin involves mixing the prepolymer and the inorganic filler. Biodegradable polyester polymerizable composition This may include the stage of obtaining (stage 2).

[0188] In other words, according to an embodiment of the present invention, an inorganic filler can be added after the completion of the first esterification reaction.

[0189] For example, if a single esterification reaction is performed, the inorganic filler can be added after the completion of the esterification reaction, and if a double esterification reaction is performed, the inorganic filler can be added after the completion of the secondary esterification reaction. The amount and type of inorganic filler used are as described above.

[0190] In particular, adding the inorganic filler after the esterification reaction is completed can improve the dispersibility of the inorganic filler, thereby minimizing aggregation, minimizing filter clogging during processing, and minimizing the difference between the initial filter pressure and the filter pressure after extrusion. Furthermore, it can minimize the occurrence of defects such as voids during the blow-blowing and extrusion stretching processes, resulting in a stable processing process and minimizing problems such as bubble bursting or rupture, thereby achieving the excellent physical properties targeted by the present invention without defects.

[0191] If the inorganic filler is added before or at the time of the esterification reaction, even if the dispersion is good during the esterification reaction stage, the viscosity may increase during the condensation polymerization stage, potentially leading to thermal decomposition or depolymerization.

[0192] Furthermore, if the inorganic filler is added after the condensation polymerization reaction, or if the inorganic filler is compounded (blended) with the final biodegradable polyester resin, not only is a large amount of inorganic filler required to achieve the above effect, but the poor compatibility between the biodegradable polyester resin and the inorganic filler can lead to void formation during the blowing process and / or extrusion stretching, potentially causing bubbles to burst or break, resulting in reduced productivity and problems that can occur as internal and surface defects in the film.

[0193] Furthermore, according to one embodiment of the present invention, a pre-treated inorganic filler may be used. When the pre-treated inorganic filler is used, the particles of the inorganic filler are easily dispersed even during the condensation polymerization reaction, which not only ensures the smooth progress of the polymerization reaction but also prevents filter clogging, minimizes the generation of voids, improves processability, productivity and moldability, and makes it possible to provide a high-quality biodegradable polyester sheet, film or molded product.

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

[0195] Furthermore, the inorganic filler can be prepared by mixing it with ultrapure water and one or more diol components selected from the group, to a slurry concentration of 10% to 30% by weight, and then pre-treating it by the method described above to add it in slurry form (inorganic filler slurry).

[0196] According to one embodiment of the present invention, the inorganic filler can be added by a drop method. For example, the drop method involves introducing the inorganic filler, or a slurry containing it, into the reactor at a drop rate of 10 kg / min or less, so that the inorganic filler does not fall directly onto the stirrer or flow down the reactor wall, and so that it falls directly onto the reactants.

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

[0198] The method for producing the biodegradable polyester resin is as follows: Biodegradable polyester polymerizable composition The process may include a step of carrying out a condensation polymerization reaction at least once (third step).

[0199] The aforementioned condensation polymerization reaction may be carried out at 180°C to 280°C and at a concentration of 1.0 torr or less for 1 to 5 hours. For example, the condensation polymerization reaction may be carried out at 190°C to 270°C, 210°C to 260°C, or 230°C to 255°C, at a concentration of 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, for 1.5 to 10 hours, 2 to 8 hours, or 2.5 to 6 hours.

[0200] Furthermore, the condensation polymerization reaction may be carried out one or more times.

[0201] Specifically, the above Biodegradable polyester polymerizable composition The mixture is then moved to a pre-polycondensation stage, where it is carried out for 1 to 5 hours at 180°C to 280°C and under a low vacuum of 100 to 300 torr. After that, it is moved to a final polycondensation stage, where, for example, a disc-ring type reactor can be used to carry out final polycondensation at 180°C to 280°C and under a 0.5 torr for 2 to 5 hours.

[0202] Furthermore, prior to the condensation polymerization reaction, the prepolymer or the Biodegradable polyester polymerizable composition A titanium-based catalyst or a germanium-based catalyst may be further added. Also, before the condensation polymerization reaction, the prepolymer or Biodegradable polyester polymerizable composition To this, one or more additives selected from the group consisting of silica, potassium, or magnesium; amine-based stabilizers such as trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, phosphorous acid, or tetraethylenepentaamine; and polymerization catalysts such as antimony trioxide or tetrabutyl titanate may be further added.

[0203] The number-average molecular weight of the polymer obtained by the aforementioned condensation polymerization 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 for the number-average molecular weight of the polymer, the physical properties and processability can be further improved.

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

[0205] Specifically, the polymer can be crystalline at temperatures below 100°C, below 70°C, or below 60°C, and then the polymer can be cut to produce polyester resin pellets.

[0206] The aforementioned cutting stage can be performed using any pellet cutting machine used in this industry without limitation, and the pellets may have various shapes. The pellet cutting method may include the underwater cutting method or the 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% to 7% by weight or less based on the total weight, and the variance index (DI) represented by formula 1 may be 3.0 or higher.

[0209] The biodegradable polyester sheet may be manufactured using the biodegradable polyester resin or polyester resin pellets.

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

[0211] The biodegradable polyester sheet has a centerline mean roughness (Ra) of 50 nm, a haze (Hz) of 50% or less, a static friction coefficient (FC) of 5 or less, and a density of 800 CC / m². 2 It can satisfy at least one of the following characteristics: oxygen permeability (OP) of less than or equal to day·atm, and tensile strength (TS) of 35 MPa or greater.

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

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

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

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

[0216] Specifically, the method for producing the biodegradable polyester film comprises a first step of producing a prepolymer by ring-opening polymerization of a lactide monomer or by esterifying it at least once using a diol component, an aromatic dicarboxylic acid component, and an aliphatic dicarboxylic acid component, and a second step of mixing the prepolymer with an inorganic filler. Biodegradable polyester polymerizable composition The second step to obtain the above Biodegradable polyester polymerizable composition The process may include a third step of obtaining a polymer by carrying out a condensation polymerization reaction at least once, a fourth step of producing pellets from the polymer, and a fifth step of drying and melt-extruding the pellets.

[0217] In the first step, the step of carrying out an esterification reaction at least once using the diol component, aromatic dicarboxylic acid component, and aliphatic dicarboxylic acid component may include the steps of mixing the diol component and aromatic dicarboxylic acid and pretreating them to obtain a slurry, and carrying out an esterification reaction at least once using a mixture containing the slurry and aliphatic dicarboxylic acid, or a mixture containing the reaction product obtained by esterifying the slurry and aliphatic dicarboxylic acid.

[0218] The first to fourth stages described above are as stated previously.

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

[0220] In the fifth step, the melt extrusion may be carried out at a temperature of 270°C or lower. For example, the melt extrusion may be carried out 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 carried out in a blown film process.

[0221] (Examples) The above will be further explained in detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the examples is not limited to these.

[0222] (Example 1) [Manufacturing of biodegradable polyester resin] <Stage 1: Step to obtain the preliminary polymer> L-lactide (100% L-lactide, Total Corbion) was placed in a reactor, and 400 ppm of tin octoate was added as a catalyst. Ring-opening polymerization was then carried out at approximately 240°C for approximately 2 hours to obtain a prepolymer.

[0223] <Phase 2: Biodegradable polyester polymerizable composition The stage of obtaining > To the preliminary polymer obtained in the first step, Biodegradable polyester polymerizable composition Based on the total weight, 50 ppm of heat stabilizer and 1% by weight of TiO2 (Oomiya Co., Ltd.) as an inorganic filler were added. Biodegradable polyester polymerizable composition I obtained it.

[0224] In this case, the inorganic filler is an inorganic filler that has been pre-treated in a mixer tank, has a D50 of 1.5 μm, and a specific surface area of ​​50 m². 2 The result was / g. The pretreatment involved stirring the inorganic filler at room temperature at a speed of approximately 300 rpm for approximately 1 hour using a slurry tank with dust explosion-proof equipment. After the esterification (ES) reaction was completed, the inorganic filler was placed in an esterification reactor and stabilized for 10 minutes.

[0225] <Stage 3: Condensation polymerization reaction> Obtained in the second stage Biodegradable polyester polymerizable composition The mixture was then continuously transferred to a pre-condensation polymerization stage and reacted at approximately 240°C under a low vacuum of approximately 100 torr for approximately 2 hours.

[0226] Subsequently, the final polymerization stage was carried out in a disc ring reactor under a pressure of 0.5 torr for approximately 3 hours. Then, while removing residual 1,4-butanediol and by-products, the molecular weight was increased at high viscosity for approximately 3 hours to produce a polymer with a number-average molecular weight of approximately 60,000 g / mol. The viscosity immediately after polymerization was 7200 poise.

[0227] <Stage 4: The process of manufacturing pellets> The polymer obtained in the third step was subjected to an underwater cutter (UWC) at 50°C to induce polymer crystallization, and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0228] [Manufacturing of biodegradable polyester sheets] After preparing two Teflon sheets, a stainless steel (SUS) frame (area 12cm x 12cm) was placed on one of the Teflon sheets. Approximately 7g of the manufactured polyester resin pellets were placed in the stainless steel (SUS) frame (area 12cm x 12cm), and then covered with the other Teflon sheet. This was then placed in the center of a hot press (WL1600SA, WITHLAB) with a surface area of ​​approximately 25cm x 25cm. This was held at approximately 240°C under a pressure of approximately 10MPa for approximately 3 minutes, then removed, and immediately cooled in water at approximately 20°C for approximately 30 seconds to produce a biodegradable polyester sheet with an area of ​​approximately 10cm x 10cm and a thickness of approximately 300μm.

[0229] [Manufacturing 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 blow film extrusion line (Yujin Engineering Co., Ltd.) to produce a biodegradable polyester film with a thickness of 50 μm.

[0230] (Example 2) [Manufacturing of biodegradable polyester resin] <Stage 1: Step to obtain the preliminary polymer> Terephthalic acid (TPA) and adipic acid (AA) were used in concentrations of 48 mol% and 52 mol%, respectively.

[0231] 1,4-butanediol (1,4-BDO) / terephthalic acid (TPA) was mixed in a ratio of 1.5 (glycol / acid (G / A)) and added to a slurry tank (the slurry tank had an anchor-type agitator at the bottom and two flat-type agitators at the top). At this time, the D50 of the terephthalic acid (TPA) was 200 μm, and the standard deviation (SD) of the terephthalic acid (TPA) relative to D50 was 20%.

[0232] Next, the mixture was stirred at 70°C at 150 rpm for 30 minutes to obtain a slurry without phase separation. The slurry was introduced into the reactor via a supply line, and 500 ppm of the titanium-based catalyst tetrabutyl titanate (Tyzor®, TnBT, Dupont) was added. A primary esterification reaction was then carried out at 210°C and atmospheric pressure for approximately 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 moles of the diol component, 52 mol% of adipic acid (AA) based on the total moles of the dicarboxylic acid component (G / A ratio of 1.1), and the titanium-based catalyst tetrabutyl titanate (Tyzor®, TnBT, Dupont) were added at a concentration of 200 ppm based on the total weight of the diol, aromatic dicarboxylic acid, and aliphatic dicarboxylic acid. A secondary esterification reaction was then carried out at 210°C and atmospheric pressure for approximately 2 hours until 95% of the by-product water was discharged, thereby producing a prepolymer with a number-average molecular weight of approximately 45,000 g / mol.

[0234] <Phase 2: Biodegradable polyester polymerizable composition The stage of obtaining > To the prepolymer obtained in the first stage, 100 ppm of a triethyl phosphate heat stabilizer is 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 a siloxane polyol (Chisso Corporation) as a dispersant, and 900 ppm of cellulose nanocrystal (cellulose nanocrystal, CNC) (particle size 190 nm) treated at 2000 rpm for 15 minutes are additionally charged, Biodegradable polyester polymerizable composition to obtain

[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 2 250 m <于

[0236] <于 <Third stage: stage of performing polycondensation reaction> The product obtained in the second stage Biodegradable polyester polymerizable composition is continuously transferred to a preliminary polycondensation stage and reacted at 240 °C under a low vacuum of about 200 torr for about 3 hours. [[ID=十七]]

[0237] Thereafter, it is transferred to the final polycondensation stage and subjected to a polycondensation reaction at about 0.5 torr for about 3 hours using a disc ring reactor. Thereafter, while removing residual 1,4-butanediol and by-products, the molecular weight is 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: stage of manufacturing pellets> The polymer obtained in the third stage is induced to form crystals of the polymer at 50 °C in an underwater cutter (UWC), and then cut with a pellet cutter to obtain biodegradable polyester resin pellets.

[0239] [Manufacture of biodegradable polyester sheets and films] Performed in the same manner as in Example 1 to produce a polyester sheet and a film, respectively.

[0240] (Example 3) As shown in Table 1 below, using CaCO3 as an inorganic filler, changing its D50 and specific surface area, and changing the input amount, and performing in the same manner as in Example 2 except that CNC was not added, a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film were produced.

[0241] (Example 4) As shown in Table 1 below, performing in the same manner as in Example 2 except that the D50 and specific surface area of the inorganic filler were changed and the input amount was changed, a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film were produced.

[0242] (Example 5) As shown in Table 1 below, using TiO2 as an inorganic filler, changing its D50 and specific surface area, and changing the input amount, and performing in the same manner as in Example 2 except that CNC was not added, a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film were produced. [[ID=])

[0243] (Comparative Example 1) As shown in Table 1 below, performing in the same manner as in Example 5 except that TiO2 as an inorganic filler was not added after the esterification reaction and was mixed (compounded) with the polymer produced after polycondensation, a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film were produced.

[0244] [[ID=)27]] (Comparative Example 2) As shown in Table 1 below, performing in the same manner as in Example 5 except that no inorganic filler was used, a biodegradable polyester resin, a biodegradable polyester sheet, and a biodegradable polyester film were produced.

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

[0246] (Example of evaluation) The following physical properties were measured and evaluated for the biodegradable polyester resin, biodegradable polyester sheet, or biodegradable polyester film produced in the above examples and comparative examples. The results are shown in Tables 1 and 2 below.

[0247] (Evaluation example 1: filter pressure) In a blow film extrusion line (Yujin Engineering Co.), using a single screw, a 40 μm mat filter (LIANDA Co.) was attached to the rear end of the gear pump inside the extruder. The biodegradable polyester resin was then extruded at approximately 240°C at the initial filter pressure (FP0) applied to the filter for 2 hours, and the filter pressure (FP2) applied to the filter was measured.

[0248] Furthermore, the filter pressure difference (ΔFP) between the initial filter pressure (FP0) and the filter pressure after 2 hours of extrusion (FP2), as shown in Equation 3 below, 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 / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C. 2 ) and FP2 is the pressure (kg / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C for 2 hours. 2 )

[0250] (Evaluation Example 2: Metal Content and Inorganic Content in Resin) The metal content and inorganic content in the biodegradable polyester resins 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. [[ID=...]]...(Evaluation Example 3: Particle Size and Specific Surface Area) The particle sizes of terephthalic acid (TPA) and the inorganic additives were measured using a particle size analyzer Microtrac S3500 (S3500, Microtrac) under the following conditions with a particle size distribution (PSD). 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 (non - condensing) max. - 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 a dynamic viscometer, the RDS (Rheometrics Dynamic Spectrometer, Discovery HR 30, TA Instrument Co.), the dynamic viscosity was measured at a temperature of 240°C while increasing the angular velocity per second (1 rad / sec = 9.5 rpm). In the case of resin viscosity, the viscosity (poise) immediately after polymerization was measured.

[0258] (Evaluation example 5: Surface roughness (Ra)) Surface roughness was measured using an AFM (Atomic Force Microscope, XE-150, Park Systems).

[0259] Specifically, test specimens were prepared by cutting the material to a length of 3 cm and a width of 3 cm according to the JIS B0601 standard. Then, the two-dimensional surface roughness was measured at five or more locations on the surface of each test specimen using the surface roughness meter, and the centerline mean roughness (Ra) was determined.

[0260] The aforementioned centerline average roughness (Ra) is the arithmetic mean roughness of the deviations of the roughness curve relative to the average line according to JIS 0161. It is calculated by summing the values ​​above and below the centerline of the reference length and dividing that value by the length of the measurement interval.

[0261] (Example of evaluation 6: Hayes) Haze was evaluated using a haze analyzer (haze-gard i, BYK Gardner, Germany). Specifically, test specimens were prepared by cutting them to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to ASTM D1003 standards, and then the haze (%) was determined using the haze analyzer as shown in Equation 4 below. [Formula 4] Haze (%) = (Total scattered light / Total transmitted light) × 100%

[0262] (Evaluation example 7: Static friction coefficient) The static friction coefficient of biodegradable polyester sheet test specimens of the examples or comparative examples was measured using a friction coefficient tester (QM110CF, QMESYS).

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

[0264] (Evaluation Example 8: Oxygen Permeability (OP)) The oxygen permeability of biodegradable polyester sheet test specimens of the examples or comparative examples was measured using Mocon's OX-TRAN 702.

[0265] Specifically, oxygen permeability was measured at a temperature of 25°C and relative humidity of 0%RH, in accordance with ASTM D3985, with a sample size of 50cm². 2 The measurement was performed using the following method. The final unit of the oxygen permeability is CC / m 2 Expressed as days and atm, a higher oxygen permeability value indicates poorer oxygen barrier properties.

[0266] (Evaluation example 9: Tensile strength (TS)) After preparing test specimens by cutting biodegradable polyester sheets manufactured according to the ASTM D638 Type V standard in the examples or comparative examples, the experiment was conducted using an Instron universal testing machine (UTM 4206-001) at a tensile speed of 100 mm / min, and the tensile strength (kgf / mm²) was measured using the machine's built-in program. 2 A pressure of 9.8 MPa was measured.

[0267] (Evaluation Example 10: Diversity Index (DI)) Using the oxygen permeability (OP) and tensile strength (TS) values ​​measured in the above evaluation examples 8 and 9, the variance index (DI) expressed by the following formula 1 was calculated.

[0268] [Formula 1] In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test specimens made from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m²) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). 2 (day·atm)

[0269] (Evaluation Example 11: Processability Reduction Index (PRI)) Using the centerline mean roughness (Ra) and haze (Hz) values ​​measured in the above evaluation examples 5 and 6, the processability reduction index (PRI) expressed 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 ​​obtained by excluding the units measured on a biodegradable polyester sheet test piece made from the biodegradable polyester resin, The aforementioned Ra is the centerline average roughness (Ra) (nm) calculated by preparing a test specimen by cutting it 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 locations on the surface of the test specimen using a surface roughness meter. The aforementioned Hz is the haze (%) measured using a haze analyzer after preparing test specimens by cutting them to a length of 5 cm, a width of 5 cm, and a thickness of 25 μm according to ASTM D1003 standards.

[0271] [Table 1]

[0272] [Table 2]

[0273] As can be seen from Tables 1 and 2 above, the inorganic filler is contained in an amount of 0.1% to 10% by weight. Biodegradable polyester polymerizable composition When a condensation polymerization reaction is carried out using this material, excellent dispersibility is achieved during the condensation polymerization process. As a result, the viscosity of the biodegradable polyester resin produced from the biodegradable composition, as well as the metal content and dispersion index (DI) within the resin, could be adjusted to an optimal range. Furthermore, the processability reduction index (PRI) and filter pressure difference (ΔFP) of the biodegradable polyester resin could be controlled to a specific range, thereby improving the overall surface roughness, haze, static friction coefficient, oxygen permeability, and tensile strength of the produced biodegradable polyester sheet.

[0274] Specifically, Examples 1 to 5 Biodegradable polyester polymerizable composition When a condensation polymerization reaction is carried out using this method, the dispersibility is excellent, and the difference between the initial filter pressure during processing and the filter pressure after 2 hours of extrusion (ΔFP) is 49 kg / cm². 2 The following and Comparative Examples 1-3 Biodegradable polyester polymerizable composition Compared to the case using [another method], the viscosity is significantly lower, and the biodegradable polyester resin obtained using this method has a viscosity of 7200 poise to 11000 poise, a dispersion index (DI) of 4.68 or higher, and the metal content in the biodegradable polyester resin can be set within an appropriate range of 0.62 to 6.03, reducing void generation in the processing process and achieving excellent tensile strength of 36 MPa to 43 MPa, as well as a viscosity of 770 cc / m 2 We were able to achieve a low oxygen permeability of less than 1 / day·atm.

[0275] Also, the above Biodegradable polyester polymerizable composition The biodegradable polyester sheet obtained using this method exhibited optimal physical properties that improve dispersibility and processability, including a haze of 53% or less, a centerline mean roughness (Ra) of 46 nm or less, a low static friction coefficient of 3.1 or less, and a processability reduction index (PRI) of 99 or less.

[0276] In contrast, as shown in Comparative Example 2, it does not contain inorganic additives. Biodegradable polyester polymerizable composition When using this method, the resulting biodegradable polyester sheet has a very high static friction coefficient of 9.8 and an oxygen permeability of 1020 cc / m³. 2It can be seen that the biodegradability of day·atm is significantly increased compared to the biodegradable polyester sheets of Examples 1-5.

[0277] Furthermore, as shown in Comparative Example 3, in the case of biodegradable polyester resin containing an excessive amount of inorganic additives, the dispersibility index (DI) is very low at 2.20 and the processability reduction index (PRI) is very high at 271, confirming that dispersibility and processability are poor. Most importantly, the filter pressure continued to rise during processing, resulting in the filter bursting.

[0278] On the other hand, it can be confirmed that the physical properties of biodegradable polyester resins, sheets, and films change significantly depending on when the inorganic filler is added.

[0279] Specifically, as in Comparative Example 1, when an inorganic additive is compounded with a biodegradable polyester resin obtained after condensation polymerization, the dispersibility decreases, and the difference between the initial filter pressure and the filter pressure after 2 hours of extrusion (ΔFP) becomes 104 kg / cm². 2 In comparison to the example in which the inorganic additive was added after the esterification (ES) reaction and before the condensation polymerization reaction, the difference in filter pressure (ΔFP) increased significantly, the viscosity of the biodegradable polyester resin dropped sharply to 7000 poise or less, haze and oxygen permeability increased significantly, and tensile strength decreased, making it impossible to achieve suitable physical properties for packaging material.

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

Claims

1. A biodegradable polyester polymerizable composition comprising an aliphatic polyester polymerizable composition or an aliphatic-aromatic polyester polymerizable composition and an inorganic filler, The aliphatic polyester polymerizable composition comprises a ring-opening prepolymer of lactide monomers, The aliphatic-aromatic polyester polymerizable composition comprises a prepolymer of part or all of the monomer composition containing a diol component and a dicarboxylic acid component. The inorganic filler is contained in an amount of 0.1% to 10% by weight based on the total weight of the biodegradable polyester polymerizable composition. The specific surface area (by BET method) of the inorganic filler is 20 m² / g to 1000 m² / g. A biodegradable polyester polymerizable composition, wherein the biodegradable polyester resin obtained by pre-polymerizing the biodegradable polyester polymerizable composition at a temperature of 240°C at 100 torr for 2 hours, and then polymerizing it at 0.5 torr for 3 hours, has a dynamic viscosity of 7,000 to 15,000 poise, as measured using a dynamic viscometer under conditions of 240°C and an angular velocity of 1 rad / sec.

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

3. The biodegradable polyester polymerizable composition according to claim 1, wherein the inorganic filler has an average particle size (D50) of 15 μm or less.

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

5. A biodegradable polyester resin formed by the biodegradable polyester polymerizable composition of claim 1, The metal content in the biodegradable polyester resin is 0.01% to 7% by weight, based on the total weight. Biodegradable polyester resin having a variance index (DI) of 3.0 or higher, as expressed in formula 1 below: [Formula 1] In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test pieces manufactured from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick test specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m³) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). ２ It is a day ATM.

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 above formula 2, Ra and Hz are numerical values ​​excluding the units measured on the biodegradable polyester sheet test piece made from the biodegradable polyester resin, The aforementioned Ra is the centerline average roughness (Ra) (nm) calculated by preparing a test specimen by cutting it 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 locations on the surface of the test specimen using a surface roughness meter. The Hz value mentioned above is the haze (%) measured using a haze analyzer after preparing test specimens by cutting them 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 a dynamic viscosity of 7000 poise or more. The biodegradable polyester resin according to claim 5, which satisfies at least one property selected from the following physical properties measured on a biodegradable polyester sheet manufactured from the biodegradable polyester resin: Centerline average roughness (Ra) of 50 nm or less, Haze (Hz) of 50% or less, Static friction coefficient (FC) of 5 or less, 800 CC / m ２ - Oxygen permeability (OP) of 1 / day·atm or less, and Tensile strength (TS) of 35 MPa or higher.

8. The biodegradable polyester resin includes 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 comprises a first repeating unit comprising a first diol residue and an aromatic dicarboxylic acid residue, and a second repeating unit comprising a second diol residue and an aliphatic dicarboxylic acid residue.

9. The biodegradable polyester resin according to claim 5, further comprising 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 in filter pressure (ΔFP) represented by the following formula 3 is 100 kg / cm ２ The biodegradable polyester resin according to claim 5, which is as follows: [Formula 3] ΔFP=│FP ０ -FP ２ │ In the above formula 3, FP ０ This is the initial pressure (kg / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C. ２ ) and FP ２ This refers to the pressure (kg / cm²) applied to the filter when the biodegradable polyester resin is extruded at 240°C for 2 hours. ２ )

11. The process includes the step of undergoing a condensation polymerization reaction at least once with the biodegradable polyester polymerizable composition of claim 1, The metal content in the biodegradable polyester resin is 0.01% to 7% by weight, based on the total weight. A method for producing a biodegradable polyester resin having a dispersion index (DI) of 3.0 or higher, as expressed in the following formula 1: [Formula 1] In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test pieces manufactured from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick test specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m³) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). ２ It is a day ATM.

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

13. Contains biodegradable polyester resin, The aforementioned biodegradable polyester resin is A biodegradable polyester resin formed by the biodegradable polyester polymerizable composition of claim 1, The metal content in the biodegradable polyester resin is 0.01% to 7% by weight, based on the total weight. A biodegradable polyester film having a dispersion index (DI) of 3.0 or higher, as expressed in formula 1 below: [Formula 1] In the above formula 1, TS and OP are numerical values ​​excluding units measured on biodegradable polyester sheet test pieces manufactured from the biodegradable polyester resin, The aforementioned TS is the tensile strength (MPa) measured using a universal testing machine at a tensile speed of 100 mm / min after preparing a test specimen according to the ASTM D638 Type V standard. The aforementioned OP was prepared by creating a 500 μm thick test specimen in accordance with ASTM D3985, and then measuring the oxygen permeability (CC / m³) using OX-TRAN 702 at a temperature of 25°C and 0% relative humidity (RH). ２ It is a day ATM.

Images