WO2014030827A1 - Method for preparing biodegradable polyester copolymer resin - Google Patents

Abstract

The present invention relates to a method for preparing biodegradable polyester copolymer resin. The method according to the present invention comprises the steps of forming an oligomer through an esterification reaction of an aliphatic dihydroxy compound, an aliphatic dicarboxylic acid compound, and an aromatic dicarboxylic acid compound, wherein the esterification reaction includes a first esterification reaction and a second esterification reaction carried out at a higher temperature than that of the first reaction, and the aliphatic dihydroxy compound is additionally introduced during the second esterification reaction. According to the method of the present invention, unreacted aromatic dicarboxylic acid is effectively controlled, and thus a complete oligomer can be formed by supplementing the insufficient aliphatic dihydroxy compound in the temperature raising step. Thus, the polymer can have sufficient physical properties.

Description

Method for preparing biodegradable polyester copolymer resin

The present invention relates to a method for producing a biodegradable polyester copolymer resin. More specifically, in order to supplement the aliphatic dihydroxy compounds that may be consumed in the elevated temperature step of the ester reaction in the preparation of the biodegradable polyester copolymer resin, a small amount of aliphatic dihydroxy compound is added at the end of the ester reaction to make the unreacted product react. The present invention relates to a method for producing a biodegradable polyester copolymer resin which induces formation of a complete oligomer to reach sufficient physical properties.

Biodegradable resin is a synthetic resin developed as a new material that does not cause environmental pollution by being decomposed into water and carbon dioxide or water and methane by microorganisms existing in nature such as bacteria, algae and mold.

Biodegradable resins commonly used with cellulose-based polymers and starches are aliphatic polyesters such as polylactic acid (PLA), polybutylene succinate (PBS), polyethylene succinate (PES), and polycaprolactone (PCL). It is a resin produced from.

These aliphatic polyester resins are excellent in biodegradability but have a disadvantage in that they lack mechanical properties. Therefore, a method of preparing a biodegradable resin in the form of an aliphatic-aromatic copolymer by synthesizing an aromatic monomer in the preparation of the biodegradable resin to complement the mechanical strength of the aliphatic polyester resin has been developed.

Representative of such biodegradable resins in the form of aliphatic-aromatic copolymers is poly (butylene adipate-co-terephthalate) (PBAT). The PBAT is prepared by removing the methanol generated by first condensation polymerization of dimethyl terephthalate as an aromatic monomer and 1,4-butanediol as an aliphatic monomer, followed by additionally adding adipic acid to remove water generated by condensation polymerization. can do.

In this case, dimethyl terephthalate (DMT) is commonly used as an aromatic monomer. Dimethyl terephthalate has the advantage that the reaction can be easily induced even at a reaction temperature of less than 180 ℃. However, there is a problem that the cost burden of the manufacturing process is large because of the high price.

Accordingly, efforts have been made to prepare copolymers using aromatic monomers which are cheaper than dimethyl terephthalate. As a representative example, a method of using terephthalic acid (PTA), which is an aromatic dicarboxylic acid, in a synthesis reaction of a copolymer has been proposed.

However, unlike the dimethyl terephthalate, such terephthalic acid has no melting point and has a property of sublimation at high temperature. In addition, terephthalic acid is present in 1,4-butanediol (BDO), which is used as a representative aliphatic monomer in the biodegradable polyester resin manufacturing process, in a slurry state below 225 ° C under normal pressure, and at a temperature of 225 ° C or higher. As the ester reaction occurs and becomes a transparent solution, a reaction temperature of 225 ° C. or higher is required to induce a uniform reaction between terephthalic acid and 1,4-butanediol. However, since 1,4-butanediol is converted into tetrahydrofuran (THF) when the temperature reaches 190 ° C under acidic conditions, copolymers with aromatic monomers requiring high temperature reaction conditions such as terephthalic acid are required. In consideration of the amount converted to tetrahydrofuran in the 1,4-butanediol must be used in excess.

In the present invention, in order to prevent the conversion of the aliphatic dihydroxy compound, the aliphatic dihydroxy compound is first reacted with an aliphatic dicarboxylic acid compound such as adipic acid which can be reacted at a relatively low temperature, and then aromatic dicarboxylic acid such as terephthalic acid. The compound is reacting.

However, the PBAT is still 1,4 at a temperature increase step up to a reaction temperature at which an aromatic monomer, such as terephthalic acid, which requires high temperature reaction conditions after the reaction of 1,4-butadiol and adipic acid is introduced, may proceed with the esterification reaction. There is a problem in that a large amount of unreacted terephthalic acid exists due to a lack of 1,4-butanediol due to conversion of butanediol to THF.

In particular, the longer the time up to the temperature at which the esterification reaction occurs in the temperature increase step, the amount of THF generated increases, and the amount of 1,4-butanediol is insufficient, so that sufficient degree of polymerization cannot be obtained in the final condensation polymerization step.

Therefore, since a facility for increasing the temperature increase rate is required in the terephthalic acid esterification step, the cost is generated, and if the coil is installed in the reactor, it may interfere with the flow of the reactant when stirring, thereby decreasing the reactivity.

Accordingly, the present inventors added a small amount of 1,4-butanediol at the end of the esterification reaction to compensate for the lack of 1,4-butanediol due to the conversion of THF in the step of raising the temperature of the ester reaction in the biodegradable polyester copolymer resin manufacturing process. The present invention was completed by revealing that unreacted terephthalic acid can be reacted to induce the formation of a complete oligomer.

The problem to be solved by the present invention is to provide a method for producing a biodegradable polyester copolymer resin that can achieve sufficient physical properties by reacting all unreacted aromatic monomers during the ester reaction to induce the formation of a complete oligomer.

In order to solve the above problems, the present invention

Esterifying the aliphatic dihydroxy compound, aliphatic dicarboxylic acid compound and aromatic dicarboxylic acid compound to form an oligomer,

Wherein the esterification reaction comprises a primary esterification reaction and a secondary esterification reaction that proceeds at a higher temperature than the first reaction, and the aliphatic dihydroxy compound is further added during the secondary esterification reaction. It provides a method for producing an ester copolymer resin.

In the method for producing a biodegradable polyester copolymer resin according to the present invention, an aliphatic dihydroxy compound, an aliphatic dicarboxylic acid compound and an aromatic dicarboxylic acid compound may be simultaneously added to proceed with primary and secondary esterification reactions. In addition, an aliphatic dihydroxy compound and an aliphatic dicarboxylic acid compound may be added during the primary esterification reaction, and an aromatic dicarboxylic acid compound may be added during the secondary esterification reaction to proceed with the reaction.

The additionally added aliphatic dihydroxy compound is preferably in the range of 0.05 to 0.5 moles relative to 1 mole based on the total amount of aliphatic and aromatic dicarboxylic acids, and further addition of the aliphatic dihydroxy compound is carried out during the secondary esterification reaction. It is preferred to be introduced at the time when the effluent does not come out.

Preferably, the aliphatic dihydroxy compound is 1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethylranol and neopentyl glycol and mixtures thereof.

Preferably, the aliphatic dicarboxylic acid compound is a compound represented by the following formula (1), anhydride or derivative thereof:

[Formula 1]

HOOC- (CH2) n-COOH

Wherein n is from 2 to 12.

In addition, the aromatic dicarboxylic acid compound is phthalic acid (phthalic acid, PA), phthalic anhydride (isophthalic acid (IPA), terephthalic acid (TPA), naphthalene-2,6-dicar It is preferably one or more selected from the group consisting of acids (naphthalene-2,6-dicarboxylic acid), anhydrides and derivatives thereof.

In addition, the first reaction proceeds first at a temperature in the range of 160 ~ 185 ℃, the second reaction is preferably proceeded sequentially at a temperature in the range of 225 ~ 250 ℃.

In addition, the poly-condensation reaction of the aliphatic-aromatic oligomer obtained by the first and second reaction in the method for producing a biodegradable polyester copolymer resin according to the present invention at 220-250 ° C., a vacuum degree of less than 2 torr for 40 to 300 minutes It is preferred to further comprise a step.

In addition, it is preferable to further include the step of reacting by adding a chain extender after the polycondensation reaction.

The effects of the present invention are as follows.

First, the present invention provides a small amount at the end of the secondary esterification reaction to compensate for 1,4-butanediol lost in the conversion of THF in the elevated temperature step for the secondary esterification reaction in the preparation of the biodegradable polyester copolymer resin. Additional 1,4-butanediol may be added to react the aromatic dicarboxylic acid not reacted with 1,4-butanediol to induce the formation of a complete oligomer.

Second, the copolymer finally obtained by effectively controlling the unreacted aromatic dicarboxylic acid can reach sufficient physical properties.

In the present invention, an aliphatic dihydroxy compound, an aliphatic dicarboxylic acid compound, and an aromatic dicarboxylic acid compound are esterified to prepare an oligomer in the process of preparing a biodegradable polyester copolymer resin, but the temperature of the secondary esterification reaction is increased. Biodegradable to form a complete oligomer by controlling the unreacted aromatic dicarboxylic acid compound by adding an aliphatic dihydroxy compound at the end of the second esterification reaction to supplement the aliphatic dihydroxy compound lost in the step. It relates to a method for producing a polyester copolymer resin.

The copolymer is an aliphatic-aromatic polyester obtained by reaction of an aliphatic dihydroxy compound with an aliphatic and aromatic dicarboxylic acid compound.

More specifically, the present invention includes esterifying an aliphatic dihydroxy compound, an aliphatic dicarboxylic acid compound, and an aromatic dicarboxylic acid compound to form an oligomer, wherein the esterification reaction is a primary ester. And a secondary esterification reaction proceeding at a higher temperature than the primary reaction and the primary reaction, wherein the aliphatic dihydroxy compound is added during the secondary esterification reaction to provide a method for preparing a biodegradable polyester copolymer resin. do.

Here, the aliphatic dihydroxy compound, the aliphatic dicarboxylic acid compound, and the aromatic dicarboxylic acid compound may be simultaneously added to proceed with the primary and secondary esterification reactions, or the aliphatic dihydroxy compound and the aliphatic dicarboxyl compound. After the acid compound is added to carry out the first esterification reaction, the aromatic dicarboxylic acid compound may be added to the second esterification reaction.

As the aliphatic dihydroxy compound in the present invention, any aliphatic dihydroxy compound used as a starting material in the preparation of aliphatic-aromatic polyester biodegradable resins can be used without limitation. Particularly in the case of aliphatic dihydroxy compounds which are likely to be converted in a high temperature reaction, they may be advantageously used, and in particular, diols having 2 to 6 carbon atoms, especially 1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethylranol and neopentyl glycol or mixtures thereof Preferred, and particularly preferably 1,4-butanediol.

In addition, as the aliphatic dicarboxylic acid compound, those generally used in the art may be used, and a relatively low temperature reaction is more preferable. Specifically, the aliphatic dicarboxylic acid compound may be a compound represented by the following formula (1), anhydrides or derivatives thereof.

[Formula 1]

HOOC- (CH2) n-COOH

Wherein n is from 2 to 12. Preferably n is used in 2 to 8.

Specific examples of such aliphatic dicarboxylic acid compounds include succinic acid (SA), glutaric acid (GA) or adipic acid (AA), as well as anhydrides and derivatives thereof.

In the present invention, phthalic acid (phthalic acid, PA), phthalic anhydride, isophthalic acid (IPA), terephthalic acid (TPA) naphthalene-2,6-dicar as the aromatic dicarboxylic acid compound. Aromatics used for the purpose of improving the mechanical properties of biodegradable resins consisting of homopolymers of aliphatic polyesters, including but not limited to acids (naphthalene-2,6-dicarboxylic acid), anhydrides or derivatives thereof. As the monomer, especially an aromatic dicarboxylic acid compound in which an esterification reaction with an aliphatic dihydroxy compound is induced at a high temperature can be advantageously used.

As an example of an aromatic dicarboxylic acid compound, terephthalic acid (PTA) has the advantage of being inexpensive compared to dimethyl terephthalate (DMT), which is usually used as an aromatic monomer, while the reaction is performed at a temperature below 185 ° C. Unlike possible dimethyl terephthalates, it is only possible to induce uniform esterification reactions with aliphatic dihydroxy compounds at temperatures above 225 ° C.

However, in the case of 1,4-butanediol (BDO) used as an example of an aliphatic dihydroxy compound in the present invention, since it is converted to tetrahydrofuran (THF) at a temperature of 190 ° C. or higher. In the temperature rising step for the secondary reaction.

In the present invention, to supplement the conversion of the aliphatic dihydroxy compound, an aliphatic dihydroxy compound is added at the end of the secondary esterification reaction to induce the formation of a complete oligomer.

On the other hand, reacting the aliphatic dihydroxy compound and the aliphatic dicarboxylic acid compound first can minimize the amount of the aliphatic dihydroxy compound present in the monomer state, and thus, the aliphatic dihydride in the high temperature reaction with the aromatic dicarboxylic acid. It is possible to reduce the amount of conversion of the oxy compound.

The two carboxylic acids included in the aliphatic dicarboxylic acid compound undergo esterification with the hydroxyl group included in the aliphatic dihydroxy compound. At this time, the aliphatic dicarboxylic acid compound may be fixed by combining an aliphatic dihydroxy compound with respect to the aliphatic dihydroxy compound, by adjusting the equivalent amount with respect to the aliphatic dihydroxy compound, and also the aliphatic dihydroxy compound. This can be fixed in combination.

Specifically, 1,4-butanediol used as an example of an aliphatic dihydroxy compound in the present invention reacts with adipic acid to form an oligomer of AA-BDO form or an oligomer of BDO-AA-BDO form.

The primary esterification reaction in which the reaction between the aliphatic dihydroxy compound and the aliphatic dicarboxylic acid compound is predominant is performed when the water flowing out of the esterification reaction reaches the effluent theoretically calculated and no more effluent occurs ( That is, the amount of water corresponding to the total number of moles of carboxylic acid contained in the aliphatic dicarboxylic acid compound) is terminated.

The primary esterification reaction is preferably carried out at a temperature range of 160 to 185 ℃, the secondary esterification reaction is higher than the primary esterification reaction proceeds at a temperature range of 225 to 250 ℃. Specifically, when terephthalic acid (PTA) is used as the aromatic dicarboxylic acid compound, since the esterification reaction proceeds uniformly at a temperature of 225 ° C or higher, the temperature of the secondary reaction is preferably in the range of 225 to 250 ° C.

As described above, aliphatic dihydroxy compounds such as 1,4-butanediol are converted to tetrahydrofuran (THF) at a temperature of 190 ° C. or higher, so that the secondary reaction proceeds with aromatic dicarboxylic acid. Since the 1,4-butanediol which should form the oligomer is converted, the aromatic dicarboxylic acid may remain unreacted, and in order to react this unreacted aromatic dicarboxylic acid, at the end of the secondary reaction, A small amount of aliphatic dihydroxy compound such as 4-butanediol is added to induce complete oligomer formation.

In this case, the amount of the aliphatic dihydroxy compound to be added may be selected in consideration of the conversion rate of the aliphatic dihydroxy compound, preferably in the range of 0.05 mol to 0.5 mol relative to 1 mol based on the total amount of aliphatic and aromatic dicarboxylic acid Will be added within. Here, if less than 0.05 mole does not appear an additional input effect, when more than 0.5 mole deviates from the purpose of the present invention to minimize the amount of 1,4-butanediol used.

In addition, the addition time is preferably added at a time when the condenser effluent no longer comes out after the second reaction.

The amount of the aliphatic dihydroxy compound may be used within the range required in the intended esterification reaction, and may be added in an amount of 1.0 mole or more with respect to 1 mole of the fatty acid and the aromatic dicarboxylic acid compound, preferably 1.3 moles or more will be added. The aliphatic dicarboxylic acid compound and the aromatic dicarboxylic acid compound are preferably used in a molar ratio of 0.4 to 0.9: 0.1 to 0.6 in terms of biodegradability, and more preferably used in a molar ratio of 0.52: 0.48. If biodegradability is not required, the aliphatic dicarboxylic acid and the compound and the aromatic dicarboxylic acid compound can be reacted in more various molar ratios.

The primary and secondary reactions can be carried out continuously or batchwise under atmospheric pressure.

According to the present invention, after the aliphatic-aromatic polyester copolymer is obtained by the first and second reactions, a biodegradable resin having desired properties can be obtained by increasing the molecular weight through a polycondensation reaction or a chain extension reaction.

Preferably, the present invention polycondensates the aliphatic-aromatic oligomers obtained from the first and second reactions for 40 to 300 minutes at a vacuum in a vacuum of less than 2 torr and at a temperature in the range of 220 to 250 ° C.

Such polycondensation reactions are intended to cause reactions between oligomer levels generated from the first and second reactions or between polymers that have not yet reached the desired molecular weight. Since the polycondensation reaction must proceed through the functional group, it proceeds in the reaction conditions of vacuum and high temperature. The reaction time of the polycondensation reaction may be adjusted according to the amount of the catalyst to be described later and the input method.

In addition, in the present invention, in order to connect two or more poly-condensation reactions of the aliphatic-aromatic polyester copolymer obtained from the first and second reactions, a chain extension reaction is carried out by adding a chain extender. As the chain extender, a polyisocyanate compound, an aromatic amine compound, or the like is used. Preferably the chain extender may be used in an amount of 0.1 to 5 parts by weight based on the copolymer.

As the polyisocyanate compound, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate and triphenylmethane One or more selected from the group consisting of triisocyanates can be used, and examples of the aromatic amine compound include 3,5-diethyl-2,4-diaminotoluene and 3,5-diethyl-2,6-dia Lonza's DETDA80 product, which contains 20 to 80 parts by weight of minotoluene, can be used.

In the present invention, in the first esterification reaction, the second esterification reaction, the polycondensation reaction and the chain extension reaction, a compound (branching agent) having a bivalent or higher polyvalent functional group is optionally added for branching reaction, thereby increasing the molecular weight and At the same time it is possible to produce polymers of branching structure.

As the branching agent, at least one polyfunctional compound selected from the group consisting of a trifunctional or higher polyhydric alcohol, a trifunctional or higher polyhydric carboxylic acid or its anhydride, a trifunctional or higher functional hydroxy carboxylic acid, and a trifunctional or higher polyvalent amine can be used. . A preferred amount of branching agent may be used in an amount of 0.1 to 3 g per mole of aliphatic and aromatic dicarboxylic acid compound.

In the present invention, the use of the branching agent or the amount of the branching agent is a factor that greatly affects the physical properties of the biodegradable resin represented by the melt flow index and the tensile / tear strength. Therefore, in the present invention, as a means for controlling the physical properties of the resin, the use of the branching agent and the amount of use of the branching agent in the respective reaction steps of the resin production is determined.

In addition, in the present invention, a catalyst or a heat stabilizer may be used to improve the efficiency of the reaction by promoting the reactions and inducing a stable reaction.

The catalysts include calcium acetate, manganese acetate, magnesium acetate, zinc acetate, monobutyl tin oxide, dibutyl tin oxide, monobutyl hydroxy tin oxide, octyl tin, dibutyl tin dichloride, tetraphenyl tin, tetrabutyl tin, Tetrabutyl titanate, tetramethyl titanate, tetraisopropyl titanate and tetra (2-ethylhexyl) titanate can be used, preferably tetrabutyl titanate (Ti (OC4H9) 4) or Vertec® VEXP 0641 (titanium). organic catalysts such as type catalyst and Johnson Matthey). The preferred amount of catalyst is to use 0.1 to 1.5 g based on 1 mole of aliphatic and aromatic dicarboxylic acid compounds.

The thermal stabilizer may further include a phosphorus compound such as triphenyl phosphate or trimethyl phosphate to react. The phosphorus compound acts to keep the reaction stable by preventing decomposition by heat when the molecular weight increase reaction proceeds at a high temperature.

The present invention will be described in detail through the following examples. However, this is only for facilitating the understanding of the present invention, and the present invention should not be construed as being limited thereto.

Example 1

In a 20 L reactor, 39 mol of 1,4-butanediol (BDO), 15.6 mol of adipic acid (AA), 9 g of tetrabutyl titanate, 3 g of triphenyl phosphate, and 9 g of malic acid as a branching agent were mixed. The esterification reaction was carried out. The reaction was terminated when the water flowing out of the first esterification reaction reached the theoretically calculated flow rate.

Next, 14.4 mol of terephthalic acid (PTA) was added to the reactor, followed by a secondary reaction while raising the temperature to 230 ° C. over 80 minutes. Subsequently, after the second reaction started, 6 mol of 1,4-butanediol was further added at the time when the effluent did not come out of the condenser. The reaction was terminated when no effluent occurred anymore and the top temperature of the reactor condenser dropped below 90 ° C.

Subsequently, the reaction product obtained from the above-mentioned primary and secondary ester reactions (ES) was polycondensation reaction (PC) for 135 minutes at 230 degreeC and the vacuum degree below 1 torr, and biodegradable resin was obtained.

Example 2

39 mol of 1,4-butanediol (BDO), 15.6 mol of adipic acid (AA), and 14.4 mol of terephthalic acid (PTA) were charged to a 20-L reactor, and 9 g of tetrabutyl titanate, 3 g of triphenyl phosphate, and a branching agent were added. 9 g of malic acid was mixed and subjected to a primary esterification reaction at 180 ° C. The reaction was terminated when the water flowing out of the primary esterification reaction through the condenser reached the theoretically calculated effluent and no more effluent occurred. Subsequently, the secondary esterification reaction was advanced, raising the temperature of the reactor to 230 degreeC over 80 minutes. Subsequently, 6 mol of 1,4-butanediol was further added at the time when the effluent did not come out after the start of the secondary reaction to proceed with the reaction. The reaction was terminated when no more effluent was generated in the condenser and the top temperature of the reactor condenser dropped below 90 ° C.

Subsequently, the reaction product obtained from the primary and secondary esterification reactions (ES) was subjected to polycondensation reaction (PC) for 135 minutes at a vacuum degree of 243 ° C. and less than 1 torr to obtain a biodegradable resin.

Comparative Example 1

A biodegradable resin was obtained in the same manner as in Example 1, except that 1,4-butanediol was not added additionally.

Comparative Example 2

A biodegradable resin was obtained in the same manner as in Example 1, except that 45 mol was added at the beginning instead of adding 1,4-butanediol.

Test Example 1

The following physical properties of the biodegradable resins obtained in Example 1 and Comparative Examples 1 and 2 were evaluated, and the results are shown in Table 1 below.

THF conversion rate : The THF content generated during ester reaction was measured by gas chromatography.

Weight average molecular weight : After preparing 0.1% by weight of chloroform solution to the resin, using a GPC (Gel Permeation Chromatography) (Agilent, HP 1100) was measured at a flow rate of 1ml / min at 35 ℃.

Table 1

As can be confirmed through Table 1, the biodegradable polyester copolymer resin according to the present invention has a molecular weight of 140,000 to 170,000 higher than the comparative example, the formation of the oligomer was made completely You can check it.

TABLE 2

It can be seen that the step of generating the most THF in the table is a temperature raising step from 200 ° C to 230 ° C. THF conversion rate is superior to the ester reaction rate in the temperature increase step, while THF occurs in the second esterification step, but esterification is superior, so as to compensate for the BOD lost in the temperature increase step as in the present invention. The final ester reaction can be completed by adding BOD at the end of the primary esterification reaction.

Claims (11)

1. Esterifying the aliphatic dihydroxy compound, aliphatic dicarboxylic acid, and aromatic dicarboxylic acid compound to form an oligomer,

   Wherein the esterification reaction comprises a primary esterification reaction and a secondary esterification reaction proceeding at a higher temperature than the primary reaction, and an additional aliphatic dihydroxy compound is added during the secondary esterification reaction. Method for producing ester copolymer resin.
2. The method of claim 1,

   The primary esterification reaction is a method for producing a biodegradable polyester copolymer resin, characterized in that the aliphatic dihydroxy compound, the aliphatic dicarboxylic acid compound and the aromatic dicarboxylic acid compound at the same time is carried out.
3. The method of claim 1,

   The aliphatic dihydroxy compound and aliphatic dicarboxylic acid compound is added during the first esterification reaction, the aromatic dicarboxylic acid compound is added during the secondary esterification reaction characterized in that the esterification proceeds Method for producing biodegradable polyester copolymer.
4. The method of claim 1,

   The additionally added aliphatic dihydroxy compound is a method for producing a biodegradable polyester copolymer resin, characterized in that added in the range of 0.05 to 0.5 mole relative to 1 mole based on the total amount of aliphatic and aromatic dicarboxylic acid.
5. The method of claim 1,

   The addition of the aliphatic dihydroxy compound is a method of producing a biodegradable polyester copolymer resin, characterized in that the input after the second reaction when the condenser effluent no longer comes out.
6. The method of claim 1,

   The aliphatic dihydroxy compound is 1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-butanediol, 1,4 -Cyclohexanediol, 1,4-cyclohexanedimethylranol and neopentyl glycol and a mixture thereof, the method for producing a biodegradable polyester copolymer resin.
7. The method of claim 1,

   The aliphatic dicarboxylic acid compound is a compound represented by the following formula (1), an anhydride or a derivative thereof, the method for producing a biodegradable polyester copolymer resin, characterized in that:

   [Formula 1]

   HOOC- (CH2) n-COOH

   Wherein n is from 2 to 12.
8. The method of claim 1,

   The aromatic dicarboxylic acid compound is a phthalic acid (PA), phthalic anhydride (phthalic anhydride), isophthalic acid (IPA), terephthalic acid (terephthalic acid (TPA), naphthalene-2,6-dicarboxylic acid (naphthalene-2,6-dicarboxylic acid), a method for producing a biodegradable polyester copolymer resin, characterized in that at least one selected from the group consisting of anhydrides and derivatives thereof.
9. The method of claim 1,

   The first reaction proceeds first at a temperature in the range of 160 ~ 185 ℃, the second reaction proceeds sequentially at a temperature in the range of 225 ~ 250 ℃ characterized in that the method for producing a biodegradable polyester copolymer resin.
10. The method of claim 1,

    Biodegradable polyester, characterized in that further comprising the step of polycondensation reaction of the aliphatic-aromatic polyester copolymer obtained by the first and second reaction at 220 ~ 250 ℃, less than 2torr for 40 to 300 minutes Method of producing copolymer resin.
11. The method of claim 10,

    Method for producing a biodegradable polyester copolymer resin, characterized in that further comprising the step of reacting by adding a chain extender after the polycondensation reaction.