KR102494714B1 - Method of preparing biodegradable polymer composition and biodegradable film prepared therefrom - Google Patents

Abstract

The present invention relates to a method for preparing a biodegradable polymer composition and a biodegradable polymer film produced therefrom, and more specifically, to a method for preparing a biodegradable polymer composition of the present invention, a high-temperature and high-pressure polymerization apparatus without generating waste solvents. And it is economical because no additional purification process is required. In addition, the biodegradable polymer film prepared by the manufacturing method according to the present invention may have excellent tear strength.

Description

Manufacturing method of biodegradable polymer composition and biodegradable film produced therefrom

The present invention relates to a method for preparing a biodegradable polymer composition and a biodegradable polymer film prepared therefrom. More specifically, the method for preparing the biodegradable polymer composition of the present invention is economical because no waste solvent is generated and no high-temperature and high-pressure polymerization equipment and additional purification processes are required. In addition, the prepared biodegradable polymer film has significantly improved tensile strength and tensile toughness and improved tear strength.

Biodegradable polymers collectively refer to polymers that can be self-degraded in vivo or in the natural environment. Among them, polylactic acid (PLA)-based resin is one of representative biodegradable polymers and is an environmentally friendly polymer obtained from corn starch.

The PLA-based resin is attracting attention for its advantages such as excellent biodegradability, low price, and easy supply, and is harmless to animals or humans and is widely used as a surgical suture or a sustained-release polymer for drugs as a medical material.

However, when the PLA resin is used alone, its mechanical properties are not sufficient, so it has physical property limitations for use in various applications requiring biodegradability. As a way to improve the weak physical properties of the PLA resin, a method of blending with other resins such as polyester is being studied.

However, there is a problem in that miscibility with the PLA resin is very poor when blended with the other resins, so it is essential to add a compatibilizer to improve the compatibility. As a specific example, when PLA and polybutylene adipate terephthalate (PBAT) are blended to improve physical properties, PLA-b-PBAT copolymer is added as a compatibilizer.

Conventionally, PLA-b-PBAT copolymers were prepared by solution polymerization or transesterification using a catalyst, but these methods are not economical because waste solvents may be generated and the production cost of the copolymer increases when a high-temperature and high-pressure polymerization device is used. There are problems that cannot be produced continuously.

Therefore, there is a need for an economical manufacturing method capable of drastically lowering the manufacturing cost through a simple manufacturing process without generating waste solvent during the preparation of the copolymer.

Republic of Korea Patent Publication No. 10-2006-0039967 (2006.05.10.)

One object of the present invention is a method for producing a biodegradable polymer composition capable of dramatically lowering the manufacturing cost by a simple manufacturing process that does not generate waste solvent and does not require a high-temperature, high-pressure polymerization device and a purification process, and biodegradable produced therefrom An object of the present invention is to provide a polymer composition and a biodegradable polymer film.

An object of the present invention is to improve the tensile strength and tensile toughness of a biodegradable polymer film, in particular, to increase the tensile toughness by more than two times compared to the case of manufacturing a biodegradable film by a conventional manufacturing method, and to improve low tear strength. It is an object of the present invention to provide a method for producing a biodegradable polymer composition having a biodegradable polymer composition and a biodegradable polymer film prepared therefrom.

One aspect of the present invention is a first step of synthesizing a block copolymer by adding an aliphatic-aromatic polyester copolymer, a lactide-based monomer and a catalyst to a first kneading machine and mixing the aliphatic-aromatic polyester copolymer at a melting point or higher; and a second step of adding and mixing the block copolymer, the aliphatic-aromatic polyester copolymer, and the polylactide-based resin in a second kneader.

In one aspect, the aliphatic-aromatic polyester copolymer may be polybutylene adipate terephthalate.

In one aspect, the first kneader and the second kneader may be an internal mixer.

In one embodiment, the catalyst is lead oxide, calcium oxide, aluminum oxide, iron (III) chloride, iron oxide, calcium chloride, manganese chloride, antimony trioxide, aluminum chloride, zinc acetate, zinc chloride, zinc bromide, boron tribromide, titanium ( Ⅲ) bromide, stannous sulfate, stannous oxide, stannous oxide, titanium tetrachloride, stannous octoate, stannous chloride (II) hydrate, stannous chloride (II), stannous chloride hydrate, p-toluene It may be at least one selected from the group consisting of sulfonic acid, tetraphenyltin, and tin (II) 2-ethyl hexanoate.

In one aspect, the weight ratio of the aliphatic-aromatic polyester copolymer and the lactide-based monomer in the first step may be 0.1 to 5:1.

In one aspect, the block copolymer may have a weight average molecular weight ratio of 2 to 5:1 of the aliphatic-aromatic polyester copolymer segment and the polylactide segment.

In one aspect, the difference between the temperature of the second kneader and the temperature of the first kneader may satisfy Equation 1 below.

[Equation 1]

T ₂ -T ₁ ≥ 20

(T ₁ is the temperature (° C.) of the first kneader, and T ₂ is the temperature (° C.) of the second kneader.)

In one aspect, the first kneader and the second kneader may be connected in series, the outlet of the first kneader communicates with the inlet of the second kneader, and the biodegradable polymer composition may be continuously produced.

Another aspect of the present invention is to provide a biodegradable polymer composition prepared from the method for preparing the biodegradable polymer composition of the present invention.

Another aspect of the present invention is to provide a biodegradable film comprising the biodegradable polymer composition of the present invention.

In another aspect, the biodegradable film has a tensile strength of 0.1 Mpa or more and an elongation at break of 200% or more.

In another aspect, the biodegradable film may have a tear strength of 2.5 N/mm or more.

In another aspect, the biodegradable film may be an agricultural mulching film, a packaging film, or an envelope film.

The method for producing a biodegradable polymer composition according to one aspect of the present invention has the advantage of significantly lowering manufacturing costs through a simple manufacturing process that does not generate waste solvents and does not require high-temperature and high-pressure polymerization equipment and purification processes.

In addition, the biodegradable polymer film prepared according to one aspect of the present invention can improve the tensile strength and tensile toughness compared to the case of manufacturing the biodegradable film by the conventional manufacturing method, and in particular, the tensile toughness is increased by more than two times, and the low Tear strength can also be improved.

Hereinafter, the present invention will be described in more detail. However, the following specific examples or examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms used in the description in the present invention are merely to effectively describe specific embodiments and are not intended to limit the present invention.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms as well, unless the context dictates otherwise.

In addition, when a certain component is said to "include", this means that it may further include other components without excluding other components unless otherwise stated.

According to the prior art, when preparing a polylactide-based copolymer to produce a biodegradable polymer composition with compatibility, waste solvent is generated in a solution process or purification process, and when a high-temperature and high-pressure polymerization device is used, the copolymer In addition to being uneconomical due to the increased production cost, there was a problem in that the biodegradable polymer composition could not be continuously produced in the same manufacturing facility. In order to solve the above problems, the present invention studied a method for producing a biodegradable polymer composition simply, economically and continuously, using two kneaders, but synthesizing a block copolymer in the first kneader, In the second kneader, the present invention was completed by continuously producing a biodegradable polymer blend.

In particular, according to the present invention, compatibility is improved, tensile strength and tensile toughness are improved, and low tear strength can also be improved through the biodegradable polymer composition containing a polylactide-based resin and an aliphatic-aromatic polyester resin. there is.

One aspect of the present invention for exhibiting the above functional effects is to add an aliphatic-aromatic polyester copolymer, a lactide-based monomer, and a catalyst to a first kneader, and mix them at a melting point or higher of the aliphatic-aromatic polyester copolymer to form a block A first step of synthesizing a copolymer; and a second step of adding and mixing the block copolymer, the aliphatic-aromatic polyester copolymer, and the polylactide-based resin in a second kneader.

Hereinafter, the present invention will be specifically described.

The aliphatic-aromatic polyester copolymer may be prepared from an aliphatic dihydroxy compound and an aromatic dicarboxylic compound, and optionally may further include an aliphatic dicarboxylic compound. The aliphatic dihydroxy compound may be a (C ₂ -C ₈ ) aliphatic dihydroxy compound, for example, ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,4-dimethyl-2-ethyl-1,3-hexanediol, 2,2-dimethyl-1 ,3-propanediol, 2-ethyl-2-butyl 1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl-1,6-hexanediol or a mixture thereof.

The aromatic dicarboxylic acid compound may be, for example, terephthalic acid, isophthalic acid, 2,6-naphthoic acid, 1,5-naphthoic acid, the aromatic dicarboxylic acid alkyl ester compound, or a mixture thereof.

The aliphatic dicarboxylic compound may be adipic acid, succinic acid or a mixture thereof.

Preferably, the aliphatic-aromatic polyester copolymer may be polybutylene adipate terephthalate derived from adipic acid, 1,4-butanediol or terephthalic acid. When a block copolymer is prepared from the polybutylene adipate terephthalate and a lactide-based monomer, and a biodegradable polymer composition and a biodegradable film containing the block copolymer are continuously prepared, the polylactide-based resin has It is preferable because it can compensate for poor tensile strength, tensile toughness and tear strength.

The first step is described in detail as follows.

In the first step, the first kneader is operated above the melting point of the aliphatic-aromatic polyester copolymer, and aliphatic-aromatic polyester, lactide-based monomers, and catalyst are added, and stirred in a molten state to form the ends of the aliphatic-aromatic polyester. A PBAT-b-PLA block copolymer in which lactide is polymerized is synthesized.

The weight ratio of the aliphatic-aromatic polyester copolymer and the lactide-based monomer in the first step may be 0.1 to 5:1, preferably 0.5 to 3:1, and more preferably 1 to 2:1. When the block copolymer is prepared in the above range, an asymmetric block copolymer is synthesized, continuously supplied to the second step, and biodegradable when mixed with polylactide-based resin and polybutylene adipate terephthalate. It is preferable because the tensile strength and tensile toughness of the sexual polymer film are remarkably improved, and the tear strength can also be improved.

The asymmetric block copolymer means that the molecular weight of the aliphatic-aromatic polyester copolymer segment is higher than that of the polylactide segment, and may specifically mean that it is twice or more higher than the molecular weight of the polylactide segment. Accordingly, the block copolymer has a weight average molecular weight ratio of the aliphatic-aromatic polyester copolymer segment and the polylactide segment of 2 to 5: 1, preferably 2 to 4: 1, more preferably 2 to 3: 1 it could be The aliphatic-aromatic polyester copolymer segment may have a weight average molecular weight of 50,000 to 300,000 g/mol, and the polylactide segment may have a weight average molecular weight of 50,000 to 150,000 g/mol. When the block copolymer is prepared with a weight average molecular weight ratio in the above range, an asymmetric block copolymer having a relatively shorter polylactide segment length is synthesized, and the block copolymer is continuously mixed with the polylactide-based resin. And when mixed with polybutylene adipate terephthalate, dispersibility is high, tensile strength and tensile toughness are remarkably improved, and tear strength can also be improved.

The catalyst is lead oxide, calcium oxide, aluminum oxide, iron (III) chloride, iron oxide, calcium chloride, manganese chloride, antimony trioxide, aluminum chloride, zinc acetate, zinc chloride, zinc bromide, boron tribromide, titanium (III) bromide, stannous sulfate, stannous oxide, stannous oxide, titanium tetrachloride, stannous octoate, stannous chloride (II) hydrate, stannous chloride (II), stannous chloride hydrate, p-toluenesulfonic acid, tetraphenyl It may be at least one selected from the group consisting of tin and tin (II) 2-ethyl hexanoate, etc. When preparing the block copolymer, a catalyst is added together to promote ring-opening polymerization of the lactide monomer.

The residence time of the aliphatic-aromatic polyester copolymer introduced into the first kneader may be 30 minutes to 1 hour. When the residence time is as described above in the first kneader, the aliphatic-aromatic polyester copolymer is completely melted and miscibility with the lactide monomer is increased, making it easy to prepare a block copolymer and also preventing oxidation by heat. can do.

Hereinafter, the second step will be described in detail.

In the second step, the block copolymer synthesized in the first step, an aliphatic-aromatic polyester copolymer, and a polylactite-based resin (polylactic acid resin) are mixed. The biodegradable polymer composition blended through the second step is can be manufactured.

The biodegradable polymer composition may include 50 to 100 parts by weight of the polylactite resin, preferably 60 to 90 parts by weight, and more preferably 70 to 90 parts by weight, based on 100 parts by weight of the aliphatic-aromatic polyester copolymer. 85 parts by weight may be included, but is not limited thereto.

In addition, the biodegradable polymer composition may include 1 to 150 parts by weight of the block copolymer synthesized in the first step, preferably 10 to 130 parts by weight, based on 100 parts by weight of the aliphatic-aromatic polyester copolymer, , More preferably, 50 to 120 parts by weight may be included, but is not limited thereto.

When preparing a blend of an aliphatic-aromatic polyester copolymer and a polylactite-based resin in the biodegradable polymer composition, as the block copolymer synthesized in the first step is included in the above content range, the biodegradable polymer composition The miscibility of is further improved, and the sea-island structure (sea-island structure; sea-island structure) can be formed more stably.

As the biodegradable polymer composition is formed in a sea-island structure, it has excellent shear force, so it is easy to process, and has excellent dispersibility, etc., and finally has excellent tensile strength, elongation at break and tear strength.

In the second step, the second kneader may be operated in a sufficiently heated state to sufficiently mix the introduced polymers, and a homogeneous biodegradable polymer composition may be prepared by mixing under the above conditions. Specifically, the block copolymer synthesized in the first step is supplied to one side of the second kneading machine, and the aliphatic-aromatic polyester copolymer and polylactite-based resin are supplied to the other side of the second kneading machine and It can be mixed homogeneously in a kneader.

The residence time of the block copolymer introduced into the second kneader may be 30 minutes to 2 hours. In the case of having the above residence time in the second kneading machine, miscibility and dispersibility with the aliphatic-aromatic polyester copolymer and polylactite-based resin are increased, and when the biodegradable polymer composition is molded into a film, excellent mechanical properties can represent

In one aspect, the first kneader and the second kneader may be an internal mixer. The kneader is an internal mixer, a closed kneader, and for example, a Banbury mixer, a batch kneader, or a twin-screw extruder may be used.

In one aspect, the difference between the temperature of the second kneader and the temperature of the first kneader may satisfy Equation 1 below.

[Equation 1]

T ₂ -T ₁ ≥ 20

T ₁ is the operating temperature (° C.) of the first kneader, and T ₂ is the operating temperature (° C.) of the second kneader.

The temperature difference may be 20 °C or more, preferably 30 °C or more, and may be 60 °C or less without limitation. For example, the temperature of the first kneader may be 120 to 190 ° C, and the temperature of the second kneader may be within 140 to 250 ° C. When the temperature difference in the above range is satisfied, a block copolymer having a relatively short polylactide segment length can be efficiently produced in the first kneading machine, and it is continuously introduced into the second kneading machine to produce polylactide When kneading together with the resin and polybutylene adipate, the dispersibility is remarkably increased, and thus the tensile strength and tensile toughness are remarkably improved, and the tear strength can also be improved.

In one aspect, the first step and the second step further include any one or a mixture of two or more selected from a first antioxidant and a second antioxidant to prevent degradation of physical properties due to oxidation of the polymer resin during processing can do. The primary antioxidant is a phenolic antioxidant, which stabilizes the radical by inducing a bond between the radical generated in the polymer during processing and hydrogen in the phenolic antioxidant, and at the same time, the phenolic antioxidant itself turns into a radical and resonates It is allowed to remain in a stable form through effect or rearrangement of electrons. The primary antioxidant is not particularly limited as long as it is a phenolic antioxidant capable of preventing oxidation by mixing with a polymer resin, and specific examples include pentaerythritol tetrakis (3-(3,5-di-tert-butyl -4-hydroxyphenyl)propionate), N,N'-hexane-1,6-diylbis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide), N ,N'-di-2butyl-1,4-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-di -tert-butylphenol, 2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 2,2'-methylene-bis(6-tert-butyl-4-methylphenol), 4 ,4'-butylidene-bis(2-tert-butyl-5-methylphenol), 4,4'-thiobis(2-tert-butyl-5-methylphenol) and octadecyl 3-(3,5 -di-tert-butyl-4'-hydroxyphenol) may be any one selected from propionate or a mixture of two or more, but is not necessarily limited thereto. In addition, the secondary antioxidant is a phosphite-based antioxidant, which can effectively prevent radicals from being generated by performing the function of a peroxide decomposer. This is combined with the primary antioxidant to realize a synergistic effect, and is more effective in terms of improving stability against ultraviolet rays. The secondary antioxidant is not particularly limited as long as it is a phosphite-based antioxidant capable of preventing oxidation by mixing with a polymer resin, preferably tris(2,4-di-tert-butylphenyl) phosphite or triphenyl phosphite. any selected from pyrite, tris(nonylphenyl)phosphite, triisodecyl phosphite, diphenyl-isooctyl-phosphite, and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-diphosphite; It may be one or a mixture of two or more, but is not limited thereto.

In one aspect, the first kneader and the second kneader may be connected in series, the outlet of the first kneader communicates with the inlet of the second kneader, and the biodegradable polymer composition may be continuously produced. By continuously producing the biodegradable polymer composition as described above, it is economical and can be preferably used in a mass production process.

As another aspect of the present invention, it may be to provide a biodegradable polymer composition prepared from the production method of the present invention.

As another aspect of the present invention, it may be to provide a biodegradable film comprising the biodegradable polymer composition of the present invention.

In another embodiment, the biodegradable film may be prepared from the biodegradable polymer composition continuously prepared in the second kneader through a known film production process. The film production process may be a blow process, and since specific production conditions are known, detailed descriptions will be omitted.

In another aspect, the biodegradable film may be an agricultural mulching film, a packaging film, or an envelope film, and is not particularly limited, but is not particularly limited, but is used in biodegradable fields requiring high mechanical strength, such as tensile strength, tensile toughness, and tear strength. can be widely applied.

In another aspect, the biodegradable film may have a tensile strength of 0.1 Mpa or more and an elongation at break of 200% or more, preferably a tensile strength of 0.15 MPa or more and an elongation at break of 250% or more, more preferably Has a tensile strength of 0.15 to 0.2 Mpa, and an elongation at break of 250 to 350%, but is not limited thereto.

Tensile toughness is significantly increased by more than two times compared to the case of producing a film using a conventional method for preparing a biodegradable composition.

In another aspect, the biodegradable film may have a tear strength of 2.5 N/mm or more, preferably 3.0 N/mm or more, and more preferably 3.0 to 4.0 N/mm, but limited thereto It is not. The biodegradable film of the present invention has an effect of improving tear strength, which may be lowered when manufacturing a film by a conventional manufacturing method.

The present invention will be described in more detail based on the following Examples and Comparative Examples. However, the following Examples and Comparative Examples are only one example for explaining the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Physical property measurement method]

1. Weight average molecular weight

For the weight average molecular weight, a molecular weight value and molecular weight distribution in terms of standard polystyrene were obtained by gel permeation chromatography (GPC) measurement using chloroform as a solvent and equipped with a refractive index sensor.

GPC equipment: ACQUITY APC from Waters

Column: Waters' ACQUITY APC ^TM

Column temperature: 30 °C

Input amount: 50 μl

Flow rate: 0.62 ml/min

2. Tensile strength and elongation at break

The prepared film was melt-injected into a dumbbell-shape of ASTM D882-Type 1B standard, and then tensile strength and elongation at break were tested according to ASTM D638 using a universal testing machine (SFM-100kN, United Calibration). .

In the tensile strength and elongation at break test, both crosshead speeds were fixed at 100 mm/min.

4. Tear strength

Tear strength was measured using an Elmendorf Tear Tester according to the ASTM D1922 method. As the tearing strength measuring device, James H. Heal & Co. Ltd.'s ElmaTear 855 tensile tester was used. As a measurement method, a film sample having a thickness of 30 mm was prepared in a horizontal or vertical direction and measured using an 8N pendulum.

[Example 1]

Based on 100 parts by weight of lactide monomer in the first kneader, 100 parts by weight of polybutylene adipate terephthalate (7070 pellet, S-enpol), 2 parts by weight of stannous octoate as a catalyst, a primary antioxidant (Irganox 1010, BASF ) 0.4 parts by weight and 0.4 parts by weight of a secondary antioxidant (Irgafos 168, BASF) were added, and kneaded at 170 ° C. and 50 rpm for 40 minutes to prepare a block copolymer.

The block copolymer synthesized in the first training machine is continuously supplied to the first side inlet of the second kneading machine, and polylactide resin (2003D, NatureWorks) 100 parts by weight, 110 parts by weight of the block copolymer and polybutyl 120 parts by weight of len adipate terephthalate, 0.22 parts by weight of a primary antioxidant (Irganox 1010, BASF), and 0.22 part by weight of a secondary antioxidant (Irgafos 168, BASF) were added and kneaded at 180 ° C. and 50 rpm for 40 minutes to achieve biodegradability. A polymer composition was prepared.

The biodegradable polymer composition was prepared into a film through a blowing process. The biodegradable polymer composition is extruded through an annular die and blown into a tubular film by forming bubbles, which after solidification are collapsed between nip rollers. The blown extrusion was carried out at a temperature of 200°C, cooled by a blowing gas at a temperature of 25°C, and the blow up ratio was 2.5.

[Example 2]

The same procedure as in Example 1 was performed except that 150 parts by weight of polybutylene adipate terephthalate was added to the first kneader based on 100 parts by weight of the lactide monomer.

[Example 3]

The same procedure as in Example 1 was performed except that 300 parts by weight of polybutylene adipate terephthalate was added to the first kneader based on 100 parts by weight of the lactide monomer.

[Example 4]

The same procedure as in Example 1 was performed except that 70 parts by weight of polybutylene adipate terephthalate was added to the first kneader based on 100 parts by weight of the lactide monomer.

[Comparative Example 1]

In Example 1, the same procedure was performed except that the block copolymer prepared in the first kneading machine was not prepared and the block copolymer was not introduced in the second kneading machine.

[Comparative Example 2]

The same procedure as in Example 1 was performed except that 10 parts by weight of polybutylene adipate terephthalate was added to the first kneader based on 100 parts by weight of the lactide monomer.

[Comparative Example 3]

In Example 1, the same procedure was performed except that the temperature of the first kneader and the second kneader was set to 200 ° C.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength (Mpa) 0.17 0.16 0.11 0.1 0.05 0.06 0.07 Elongation at break (%) 310 290 230 250 20 50 110 Tear strength (N/mm) 3.7 3.6 2.5 3.1 2.0 2.1 2.2

As described above, the present invention has been described with specific details and limited examples, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above examples, and the field to which the present invention belongs Those skilled in the art can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

Claims (13)

A first step of synthesizing an asymmetric block copolymer by introducing an aliphatic-aromatic polyester copolymer, a lactide-based monomer, and a catalyst into a first kneading machine and mixing the aliphatic-aromatic polyester copolymer at a melting point or higher; and
a second step of introducing and mixing the asymmetric block copolymer, the aliphatic-aromatic polyester copolymer, and the polylactide-based resin in a second kneader;
Including,
The asymmetric block copolymer has a weight average molecular weight ratio of the aliphatic-aromatic polyester copolymer segment and the polylactide segment of 2 to 5: 1,
The first kneader and the second kneader are connected in series, the outlet of the first kneader communicates with the inlet of the second kneader, and a method for producing a biodegradable polymer composition that continuously produces a biodegradable polymer composition. . According to claim 1,
The aliphatic-aromatic polyester copolymer is a method for producing a biodegradable polymer composition of polybutylene adipate terephthalate. According to claim 1,
The first kneader and the second kneader are internal mixers, a method for producing a biodegradable polymer composition. According to claim 1,
The catalyst is lead oxide, calcium oxide, aluminum oxide, iron (III) chloride, iron oxide, calcium chloride, manganese chloride, antimony trioxide, aluminum chloride, zinc acetate, zinc chloride, zinc bromide, boron tribromide, titanium (III) bromide, stannous sulfate, stannous oxide, stannous oxide, titanium tetrachloride, stannous octoate, stannous chloride (II) hydrate, stannous chloride (II), stannous chloride hydrate, p-toluenesulfonic acid, tetraphenyl A method for preparing a biodegradable polymer composition comprising at least one selected from the group consisting of tin and tin (II) 2-ethyl hexanoate. According to claim 1,
The method of producing a biodegradable polymer composition in which the weight ratio of the aliphatic-aromatic polyester copolymer and the lactide-based monomer in the first step is 0.1 to 5: 1. delete According to claim 1,
The difference between the temperature of the second kneader and the temperature of the first kneader is a method for producing a biodegradable polymer composition that satisfies the following formula 1.
[Equation 1]
T ₂ -T ₁ ≥ 20
(T ₁ is the temperature (° C.) of the first kneader, and T ₂ is the temperature (° C.) of the second kneader.) delete A biodegradable polymer composition prepared by the method of any one of claims 1 to 5 and 7. A biodegradable film comprising the biodegradable polymer composition of claim 9. According to claim 10,
The biodegradable film has a tensile strength of 0.1 Mpa or more, and an elongation at break of 200% or more. According to claim 10,
The biodegradable film is a biodegradable film having a tear strength of 2.5 N / mm or more. According to claim 10,
The biodegradable film is a biodegradable film of agricultural mulching film, packaging film or envelope film.