KR20200062615A - A preparation method of High molecular weight aliphatic carbonate and aromatic ester copolymer resin - Google Patents

Abstract

Disclosed in the present invention is a method for preparing high-molecular-weight aliphatic carbonate and aromatic ester copolymer with an excellent color while minimizing constraints in a polymerization reaction and a loss of raw materials according to use of dimethyl carbonate as a monomer when preparing an existing aliphatic polycarbonate copolymer. The present invention provides a method for preparing aliphatic carbonate represented by the formula 4 and aromatic ester copolymer, comprising the steps of: (a) reacting a compound represented by the formula 1 and a compound represented by the formula 2 to carry out an esterification reaction; (b) mixing a compound represented by the formula 3 in a reaction product of the esterification reaction to carry out a trans-esterification reaction; and carrying out a condensation polymerization reaction for a reaction product of the trans-esterification reaction.

Description

A preparation method of High molecular weight aliphatic carbonate and aromatic ester copolymer resin}

The present invention relates to a method for producing an aliphatic carbonate and an aromatic ester copolymer, and more particularly, to a method for preparing an aliphatic carbonate and an aromatic ester copolymer of high molecular weight with excellent color.

Biodegradable plastic refers to plastic that can be decomposed into low molecular substances by microorganisms existing in nature and finally decomposed into water and carbon dioxide or water and methane gas. While eco-friendly awareness is rising throughout the industry, the use of such biodegradable plastics has been extensively researched and developed, and has higher utilization in non-recyclable disposable products such as packaging materials or agricultural films.

Representative biodegradable plastics include polylactic acid, copolymers of aliphatic hydroxy carboxylic acids, aliphatic polyhydric alcohols, and aliphatic polyesters and aliphatic-aromatic polyester copolymers derived from aliphatic polycarboxylic acids. However, the aliphatic polyester has high hardness due to high crystallinity, and the physical properties such as tear strength, tensile strength, and elongation of the product are weak, and it is easy to deteriorate the physical properties of the resin over time due to the initial rapid biodegradability. Is emerging. The aliphatic-aromatic polyester system was developed to improve the low mechanical properties of the aliphatic polyester, and exhibits superior elongation and tear strength than the aliphatic polyester. However, there is a disadvantage in that the ester bond is hydrolyzed by the moisture and high humidity environment in the atmosphere, thereby deteriorating the physical properties of the final product. In particular, the film used for packaging and shopping bags has a problem that it is easily hydrolyzed within 2 to 3 months when it is exposed to a high temperature and high humidity environment due to its thin thickness.

Aliphatic polycarbonates or partially aromatic polyester copolymers thereof are also biodegradable eco-friendly polymers. This polycarbonate ester copolymer has no acid value, unlike the existing polyester system, and has relatively good hydrolysis resistance, so there is no deterioration in physical properties of the final product, and it is easy to change the composition due to the multi-component structure, so that crystallization rate and biodegradability can be controlled. It is possible. Attempts to manufacture aliphatic polycarbonates with high molecular weights have been made, but most have been unsuccessful in terms of manufacturing methods and economics. On the other hand, Korean Registered Patent No. 13686916 discloses a method for preparing a high molecular weight aliphatic polycarbonate copolymer through condensation reaction of 1,4-butanediol, dimethyl carbonate (DMC) and dimethyl terephthalate under a base catalyst. .

However, the dimethyl carbonate used as a monomer in the preceding patent needs to be categorized in the polymerization reaction in the condensation reaction due to its low boiling point (90°C) (more than 90°C in the first step, more than 150°C in the second step), and dimethyl carbonate with high volatility In the polymerization process, it should be removed and separated like methanol, which is a polymerization by-product, by being added in an excess of 1.5 to 2 times. Due to this, the manufacturing cost increases due to the addition of the polymerization step and separation process according to the use of dimethyl carbonate in the continuous polymerization process.

In addition, the dimethyl terephthalic acid used as a monomer in the preceding patent is more expensive than terephthalic acid and causes a rise in production cost, and there is a problem in that the method proposed in this patent cannot apply terephthalic acid. That is, in the method proposed in this patent, since the condensation reaction proceeds under the base catalyst, when the terephthalic acid, an acid, is applied, the catalytic activity is lost due to the acid base reaction and polymerization does not proceed. In addition, even if a metal catalyst (titanium-based, antimony-based, etc.) acting on terephthalic acid is used, a reaction temperature of 200° C. or higher is required to participate in the reaction, and at this reaction temperature, dimethyl carbonate volatilizes and polymerization does not proceed properly. can not do it.

Therefore, the present invention was devised to solve the above problems, and it has a high molecular weight aliphatic carbonate and aromatic ester with excellent color while minimizing polymerization reaction constraints and raw material loss due to the use of dimethyl carbonate as a monomer in the preparation of a conventional aliphatic polycarbonate copolymer. It is intended to provide a method for preparing a copolymer.

In order to solve the above problem, the present invention, (a) reacting the compound represented by the following formula (1) and the compound represented by the following formula (2) to perform an esterification reaction; (B) a step of performing a transesterification reaction by mixing a compound represented by the following formula (3) to the reaction product of the esterification reaction; And (c) by performing a condensation polymerization reaction on the reaction product of the transesterification reaction provides a method for producing an aliphatic carbonate and an aromatic ester copolymer represented by the following formula (4).

[Formula 1]

In Formula 1, A may be a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms or a substituted or unsubstituted heteroalkylene group having 1 to 10 carbon atoms, and nitrogen, oxygen, silicon, phosphorus, or sulfur elements may be included in the structure. Can;

[Formula 2]

In Formula 2, B is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and the structure may include nitrogen, oxygen, phosphorus, sulfur or silicon;

R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted heteroalkyl group having 1 to 20 carbon atoms, and may include a ring form, and nitrogen, oxygen in the structure , Phosphorus, sulfur or silicon;

[Formula 3]

In Formula 3, R ₃ and R ₄ are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms;

[Formula 4]

In Chemical Formula 4, A and B are the same as in Chemical Formulas 1 and 2, respectively, and x and y are real numbers representing mole fractions.

In addition, the compound represented by the formula (1) is ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4- 1 type selected from the group consisting of butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, neopentyl glycol, trimethylene glycol, 1,6-hexanediol and 1,10-decanediol Above, the compound represented by Formula 2 is dimethyl terephthalic acid, terephthalic acid, dimethylphthalic acid, phthalic acid, dimethyl isophthalic acid, isophthalic acid, naphthalenedicarboxylic acid, dimethylnaphthalene 2,6-dicarboxylic acid and naphthalene 2,6- At least one member selected from the group consisting of dicarboxylic acids, and the compound represented by Formula 3 is diphenyl carbonate, bis(4-methylphenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(4-fluoro It provides a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that at least one member selected from the group consisting of phenyl) carbonate, bis (4-nitrophenyl) carbonate and bis (2-nitrophenyl) carbonate.

In addition, step (a) provides a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that the reaction temperature is 200 to 250°C and a pressure of 0.5 to 2 atmospheres.

In addition, the step (b) provides a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that it is carried out at a reaction temperature of 200 to 250°C and a pressure of 200 to 600 mmHg.

In addition, the step (c) provides a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that it is carried out at a reaction temperature of 200 to 250°C and a pressure of 0.1 to 10 mmHg.

In addition, the copolymer has an aliphatic carbonate characterized by having a weight average molecular weight of 10,000 to 100,000, a polydispersity index (PDI, Mw/Mn) of 1.5 to 2.5, a Color L value of 80 or more, and a Color b value of 3 or less, and A method for producing an aromatic ester copolymer is provided.

According to the present invention, by replacing the dimethyl carbonate used as a monomer in preparing the existing aliphatic polycarbonate copolymer, by introducing a carbonate monomer having an aryl group having a higher boiling point than dimethyl carbonate such as diphenyl carbonate, there is no restriction of polymerization reaction and raw material loss By minimizing to increase the process efficiency, it is possible to prepare a high molecular weight aliphatic carbonate and aromatic ester copolymer having excellent color.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the description of the present invention, when it is determined that a detailed description of related known technologies may obscure the subject matter of the present invention, the detailed description will be omitted. Throughout the specification, when a part “includes” a certain component, this means that other components may be further included instead of excluding other components, unless specifically stated to the contrary.

The present inventors faced a problem of the polymerization reaction temperature limitation and raw material loss due to the use of a dimethyl carbonate monomer having a low boiling point in the polymerization process of a conventional aliphatic polycarbonate copolymer, and as a result of repeated studies to solve the problem, dimethyl carbonate was replaced. By introducing a carbonate monomer having a high boiling point aryl group such as diphenyl carbonate, it has been found that a high molecular weight aliphatic carbonate and an aromatic ester copolymer having excellent color while minimizing raw material loss and without limitation of polymerization reaction can be produced. It came to the invention.

Accordingly, the present invention (a) reacting the compound represented by the following formula (1) and the compound represented by the following formula (2) to perform an esterification reaction; (B) a step of performing a transesterification reaction by mixing a compound represented by the following formula (3) to the reaction product of the esterification reaction; And (c) by performing a condensation polymerization reaction on the reaction product of the transesterification reaction provides a method for producing an aliphatic carbonate and an aromatic ester copolymer represented by the following formula (4).

[Formula 1]

In Formula 1, A may be a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms or a substituted or unsubstituted heteroalkylene group having 1 to 10 carbon atoms, and nitrogen, oxygen, silicon, phosphorus, or sulfur elements may be included in the structure. Can;

[Formula 2]

In Formula 2, B is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and the structure may include nitrogen, oxygen, phosphorus, sulfur or silicon;

R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted heteroalkyl group having 1 to 20 carbon atoms, and may include a ring form, and nitrogen, oxygen in the structure , Phosphorus, sulfur or silicon;

[Formula 3]

In Formula 3, R ₃ and R ₄ are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms;

[Formula 4]

In Chemical Formula 4, A and B are the same as in Chemical Formulas 1 and 2, respectively, and x and y are real numbers representing mole fractions.

The compound represented by Formula 1 is an aliphatic diol, for example, ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, 1,2-propanediol, 1 ,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, neopentyl glycol, trimethylene glycol, 1,6-hexanediol and 1,10-decanediol It may be one or more kinds, preferably 1,4-butanediol.

In addition, the compound represented by Formula 2 is an aromatic ester compound, for example, dimethyl terephthalic acid, terephthalic acid, dimethylphthalic acid, phthalic acid, dimethyl isophthalic acid, isophthalic acid, naphthalenedicarboxylic acid, dimethylnaphthalene 2,6-dicarboxylic acid and It may be one or more selected from the group consisting of naphthalene 2,6-dicarboxylic acid, and preferably terephthalic acid.

In addition, the compound represented by the formula (3) is a carbonate compound, in the present invention, in order to solve the limitation of polymerization reaction and raw material loss due to dimethyl carbonate used as a monomer in the preparation of an existing aliphatic polycarbonate copolymer, such as diphenyl carbonate. Carbonate monomers having an aryl group with a high boiling point are introduced.

As such compounds, for example, diphenyl carbonate, bis(4-methylphenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(4-fluorophenyl)carbonate, bis(4-nitrophenyl)carbonate and bis(2-nitro It may be one or more selected from the group consisting of phenyl) carbonate, preferably diphenyl carbonate.

Hereinafter, a method for preparing the aliphatic carbonate and aromatic ester copolymer according to the present invention will be described in detail by exemplifying the cases in which the compounds represented by Chemical Formulas 1 to 3 are 1,4-butanediol, terephthalic acid, and diphenyl carbonate, respectively.

In Scheme 1 below, a process for preparing an aliphatic carbonate and an aromatic ester copolymer according to the present invention is shown.

[Scheme 1]

First, through the esterification reaction of 1,4-butanediol and terephthalic acid, a pre-oligomer of Formula 5 is produced.

[Formula 5]

In the formula (5), n is a repeating unit 2 to 10.

In the esterification polymerization step, a 1,4-butanediol (-OH functional group) and terephthalic acid (-CO ₂ H functional group) molar ratio is 1.0 to 2.0:0.4, preferably a mixture having a molar ratio of 1.4 to 1.6:0.4 is subjected to an esterification reaction. This step is to prepare the pre-oligomer by removing the by-product water. At this time, the reaction temperature is preferably 200 ~ 250 ℃, more preferably may be 210 ~ 220 ℃. If the reaction temperature is too low, the reaction may not occur because terephthalic acid does not melt. If it is too high, 1,4-butanediol does not participate in the reaction and is converted to tetrahydrofuran, and the temperature is accelerated at 230°C or higher. The esterification reaction may produce a pre-oligomer represented by Chemical Formula 5 in which most or all of the end groups of the reaction product are substituted with hydroxyl groups.

Next, a polyphenylene carbonate-co-terephthalate represented by the following Chemical Formula 6 through a transesterification reaction by mixing diphenyl carbonate with the reaction product (Formula 5) of the esterification reaction (poly (butylene carbonate-co-terephthalate)) , PBCT) polymer.

[Formula 6]

In the formula (6), x and y are real numbers representing the mole fraction.

In the transesterification polymerization step, diphenyl carbonate (-COO-Ph functional group) is introduced into the esterification reaction product (Formula 5) in a stepwise reaction at a molar ratio of about 0.6. The reaction temperature is preferably 200 to 250°C, and more preferably 210 to 220°C. At this time, in order to effectively remove the phenol generated as a by-product, it can be reacted under reduced pressure of 200 to 600 mmHg, preferably 300 to 500 mmHg. When proceeding to normal pressure in this step, phenol is not effectively removed, so diphenyl carbonate does not participate properly in the reaction, and the color of the polymer may discolor yellow due to the effect of phenol. Therefore, it is necessary to effectively remove phenol to obtain a high molecular weight PBCT polymer with excellent color.

Next, as a condensation polymerization step, the condensation polymerization may be performed under a vacuum reduced pressure of 0.1 to 10 mmHg, preferably 0.1 to 2 mmHg, after a portion of the by-product phenol is partially removed under a certain reduced pressure in the transesterification step. The reaction temperature may be 200 to 250°C, preferably 210 to 220°C. When the polymerization temperature is low, the reactivity of the oligomer is low, which is undesirable because the polymerization time is increased. If it is too high, thermal decomposition of the resulting polymer occurs, which is undesirable. On the other hand, the condensation polymerization is preferably terminated when the viscosity of the reactants is 20 to 30 Ncm based on the torque value.

In the present invention, a titanium-based catalyst may be added in the esterification reaction step. The titanium-based catalyst is any one or two or more mixed catalysts selected from the group consisting of tetraisopropyl titanate, tetrabutoxy titanate, tetrabutyl titanate, tetraethylene titanate, tetrastearyl titanate, and titanium acetoacetate. Can be preferably used, more preferably tetrabutyl titanate can be used.

The amount of the catalyst added in the present invention may be 0.0001 to 0.002 moles, and preferably 0.0005 to 0.001 moles, based on 1 mole of dicarboxylic acid used in the esterification reaction. If the amount of catalyst addition is less than the reference value, there may be a limit in raising the molecular weight by losing activity as a catalyst at a certain time, and if it exceeds the reference value, the reaction rate increases but the color may deteriorate.

The PBCT resin obtained according to the above method may be adjusted to vary according to the molar ratio of carbonate residues of Formula 2, that is, the molar ratio of x (x/(x+y)). As the molar ratio decreases, the melting point and the transition temperature increase, and by controlling the molar ratio of x, it is possible to easily adjust the properties of the resin required. However, if the molar ratio of the diphenyl carbonate to be added cannot properly participate in the reaction according to the polymerization method, the molar ratio of the carbonate residue may be reduced than the molar ratio to be added.

The PBCT resin finally produced by the above method may be made of a resin having a weight average molecular weight (Mw) of 15,000 to 100,000, preferably 70,000 or more. In particular, the color of the resin may have an L value of 70 or more, an a value of -3.0 to 1.0, and a b value of 1 to 20 represented by an L*a*b* colorimetric system. More preferably, a resin having an L value of 80 or more and a value of 3 or less can be produced if phenol, a by-product, is effectively removed under a specific pressure in the transesterification step. The L-value, a-value, and b-value are indices of hue displayed in the CIE-L*a*b* (CIE 1976) colorimeter. The L value represents brightness, and the larger this value, the brighter. The b value represents the degree of yellowness, and the larger the value, the higher the yellowness.

Hereinafter, the present invention will be described in more detail with reference to examples according to the present invention.

Example 1

After adding 1,4-butanediol to 80 g (0.88 mmol) and terephthalic acid to 59 g (0.35 mmol) in a 500 mL flask, 0.15 g of Titanium(IV) butoxide was added as a catalyst, and mixed under nitrogen stream in a slurry state. The esterification reaction proceeded. The reaction was carried out at normal pressure at a stirring speed of 100 rpm for 3 hours at 210°C. Pre-oligomer fmf polymerization was performed by distilling off water and tetrahydrofuran generated during the esterification reaction. At this time, 1,4-butanediol is partially converted to tetrahydrofuran by side reaction, and an excess amount of 1,4-butanediol is added in order to completely replace the esterified pre-oligomeric end group portion with a hydroxyl group.

Next, diphenyl carbonate was added to the 114 g (0.53 mmol) reactor as a transesterification step, and the reaction was performed under a 300-500 mmHg vacuum condition over 2 hours at 210°C. At this time, it is important to maintain the vacuum well and polymerize the oligomer in order to effectively remove the phenol generated in the transesterification reaction.

Lastly, as a condensation polymerization step, the reaction was progressed while gradually reducing the pressure of the reactor from 300 mmHg to 0.5 mmHg after removing a portion of phenol as a by-product under a specific pressure in the transesterification step. The reaction was conducted at 210°C for 2 hours and 30 minutes, and the reaction was terminated while observing the torque value of the stirrer (IKA Eurostar 200 control) at the time of discharge of the final polymer.

Example 2

The esterification, transesterification and condensation polymerization reactions were carried out in the same manner as in Example 1, except that 104 g (1.15 mmol) of 1,4-butanediol was added in Example 1.

Example 3

The esterification, transesterification and condensation polymerization reactions were carried out in the same manner as in Example 1, except that 120 g (1.33 mmol) of 1,4-butanediol was added in Example 1.

Example 4

The esterification, transesterification, and condensation polymerization reactions were performed in the same manner as in Example 1, except that 160 g (1.77 mmol) of 1,4-butanediol was added in Example 1.

Example 5

In a 500 ml flask, 1,4-butanediol was added to 120 g (1.33 mmol), terephthalic acid was added to 59 g (0.35 mmol), and 0.15 g of Titanium(IV) butoxide was added as a catalyst, followed by the same method as in Example 1. The esterification proceeded to polymerize the pre-oligomer.

Next, as a transesterification step, diphenyl carbonate was introduced into a 114 g (0.53 mmol) reactor, and the reaction was carried out by changing the pressure conditions step by step at a reaction temperature of 210°C. First, the reaction was performed at normal pressure (760 mmHg) for 1 hour, and then the pressure was reduced to react at 300 to 500 mmHg for 1 hour to polymerize the oligomer.

Finally, the condensation polymerization step was performed in the same manner as in Example 1.

Example 6

In a 500 ml flask, 1,4-butanediol was added to 120 g (1.33 mmol), terephthalic acid was added to 59 g (0.35 mmol), and 0.15 g of Titanium(IV) butoxide was added as a catalyst, followed by the same method as in Example 1. The esterification proceeded to polymerize the pre-oligomer.

Next, as a transesterification step, diphenyl carbonate was added to a 114 g (0.53 mmol) reactor, and the reaction temperature was 210° C. and atmospheric pressure (760 mmHg) for 2 hours to polymerize the oligomer.

Finally, the condensation polymerization step was performed in the same manner as in Example 1.

Comparative example

In a 500 ml flask, 1,4-butanediol was added to 120 g (1.33 mmol), terephthalic acid to 59 g (0.35 mmol), diphenyl carbonate was added to 114 g (0.53 mmol), and as a catalyst, titanium (IV) butoxide was 0.15. After adding g, the esterification/transesterification reaction was carried out at normal pressure in the same manner as in Example 1. Subsequently, the condensation polymerization step was performed in the same manner as in Example 1.

The reaction conditions according to the Examples and Comparative Examples are summarized in Table 1 below.

Test example

The molar ratio of ester/carbonate moieties, molecular weight, thermal properties and color were measured by the following methods for the resins obtained according to the examples and comparative examples, and the results are shown in Table 2 below.

[How to measure]

(1) Molar ratio of ester/carbonate residue

After dissolving the obtained resin in a chloroform (CDCl ₃ ) solvent for NMR (Nuclear Magnetic Resonance), take the quantity and confirm the structure of the final product through 500 MHz NMR, and the ester in the entire resin through the integral value of 1H peak/ The molar ratio of carbonate residues was determined.

(2) molecular weight

PBCT polymer was pre-treated with tetrahydrofuran (THF) at a concentration of 0.01 g/ml, followed by gel permeation chromatography (GPC-Waters2690 model HPLC/RI Detector), to obtain a weight average molecular weight (Mw) and a number average molecular weight (Mn). Was measured. At this time, it was measured at a flow rate of 1.0 ml/min at 40°C, and polystyrene was used as a standard material.

(3) Thermal properties

The temperature increase rate from the analysis temperature of -50 to 200°C was measured with a scanning calorimeter (DSC-Q200 (TA Instruments Co.)) at 10°C/min.

(4) color

Fill the PBCT polymer chip in a glass cell (10 mm inside diameter x 50 mm depth) and L in the CIE-L*a*b* (CIE 1976) colorimeter using an X-Rite (Color-Eye 7000A) colorimeter. *, a* and b* were measured.

Referring to Table 1 and Table 2, in accordance with the present invention, a carbonate monomer having a high boiling point aryl group such as diphenyl carbonate is introduced by replacing the existing dimethyl carbonate, and the esterification reaction and the transesterification reaction are carried out stepwise. In addition, when the transesterification reaction is performed under reduced pressure under specific conditions (Examples 1 to 4), it can be confirmed that polymerization of a high molecular weight PBCT resin with excellent color is possible without limitation of polymerization.

At this time, in the esterification reaction, the molar ratio of 1,4-butanediol (-OH functional group) and terephthalic acid (-CO ₂ H functional group) is from 1.3 to 2.0:0.4, more preferably, the most ideal oligomer is polymerized from molar ratio of 1.4 to 1.6:0.4 It can be seen that.

However, in the transesterification reaction step, when reacting under normal pressure or normal pressure and vacuum conditions (Examples 5 and 6), phenol generated as a by-product cannot be surely removed, and finally, diphenyl carbonate (DPC) does not properly participate in the reaction. It is understood that the content of carbonate groups in the final PBCT polymer resin is lowered, and this is a factor that cannot be polymerized according to the molar ratio in which diphenyl carbonate is added, and the molar ratio is changed in the polymerization process, thereby preventing polymerization.

On the other hand, when 1,4-butanediol, terephthalic acid and diphenyl carbonate are simultaneously added to perform the reaction (comparative example), diphenyl carbonate is hydrolyzed to phenol and CO ₂ by water generated as a by-product as shown in Reaction Scheme 2 below. do.

[Scheme 2]

Thus, polyphenylene terephthalate (PBT) resin in which the diphenyl carbonate did not participate in the polymerization reaction at all and had only a carbonate group and no ester group in the final resin composition was polymerized. Due to these problems, it can be confirmed that in order to successfully polymerize PBCT, it is effective to remove phenol by maintaining a specific pressure in the step of splitting and transesterification of raw materials.

The preferred embodiments of the present invention have been described above in detail. The description of the present invention is for illustrative purposes, and those skilled in the art to which the present invention pertains will appreciate that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the claims, which will be described later, rather than by the detailed description, and all the changed or modified forms derived from the meaning, scope, and equivalent concepts of the claims are included in the scope of the present invention. Should be interpreted.

Claims (6)

(a) reacting a compound represented by Formula 1 and a compound represented by Formula 2 below to perform an esterification reaction;
(B) a step of performing a transesterification reaction by mixing a compound represented by the following formula (3) to the reaction product of the esterification reaction; And
(c) a method for preparing an aliphatic carbonate and an aromatic ester copolymer represented by the following Chemical Formula 4 by performing a condensation polymerization reaction on the reaction product of the transesterification reaction:
[Formula 1]

In Formula 1, A may be a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms or a substituted or unsubstituted heteroalkylene group having 1 to 10 carbon atoms, and nitrogen, oxygen, silicon, phosphorus, or sulfur elements may be included in the structure. Can;
[Formula 2]

In Formula 2, B is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, and the structure may include nitrogen, oxygen, phosphorus, sulfur or silicon;
R ₁ and R ₂ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted heteroalkyl group having 1 to 20 carbon atoms, and may include a ring form, and nitrogen, oxygen in the structure , Phosphorus, sulfur or silicon;
[Formula 3]

In Formula 3, R ₃ and R ₄ are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms;
[Formula 4]

In Formula 4, A and B are the same as in Formulas 1 and 2, respectively, and x and y are real numbers representing the mole fraction. According to claim 1,
Compound represented by the formula (1) is ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, neopentyl glycol, trimethylene glycol, 1,6-hexanediol and 1,10-decanediol. ,
The compound represented by the formula (2) is dimethyl terephthalic acid, terephthalic acid, dimethylphthalic acid, phthalic acid, dimethyl isophthalic acid, isophthalic acid, naphthalenedicarboxylic acid, dimethylnaphthalene 2,6-dicarboxylic acid and naphthalene 2,6-dicarboxyl One or more selected from the group consisting of acids,
The compound represented by Chemical Formula 3 is diphenyl carbonate, bis(4-methylphenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(4-fluorophenyl)carbonate, bis(4-nitrophenyl)carbonate and bis( Method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that at least one member selected from the group consisting of 2-nitrophenyl) carbonate. According to claim 1,
The step (a) is a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that it is carried out at a reaction temperature of 200 to 250°C and a pressure of 0.5 to 2 atmospheres. According to claim 1,
The step (b) is a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that it is carried out at a reaction temperature of 200 to 250°C and a pressure of 200 to 600 mmHg. According to claim 1,
The step (c) is a method for producing an aliphatic carbonate and an aromatic ester copolymer, characterized in that it is carried out at a reaction temperature of 200 to 250°C and a pressure of 0.1 to 10 mmHg. According to claim 1,
The copolymer has an aliphatic carbonate and an aromatic ester characterized by having a weight average molecular weight of 10,000 to 100,000, a polydispersity index (PDI, Mw/Mn) of 1.5 to 2.5, a color L value of 80 or more, and a color b value of 3 or less. Method for preparing a copolymer.