KR20190076681A - Method for Preparing Polyalkylene Terephthalate glycol - Google Patents

Abstract

The present invention relates to a method for preparing polyalkylene terephthalate glycol and, more specifically, to a method for preparing polyalkylene terephthalate glycol resin with high viscosity and excellent color in a short process time. According to the present invention, the method for preparing polyalkylene terephthalate glycol can produce high-performance plastics having a very high intrinsic viscosity and a transparent color like glass as a resin in which glycol is added to PET conventionally used in fibers, bottles, films and like. Also, the preparation method of the present invention can prepare polyalkylene terephthalate glycol resin with high intrinsic viscosity and excellent color in a very short reaction time by transferring a half of a monomer reaction product to a polymer reactor and adding a reactant slurry to the remainder to carry out the monomer reaction.

Description

TECHNICAL FIELD The present invention relates to a method for preparing polyalkylene terephthalate glycol,

The present invention relates to a process for producing polyalkylene terephthalate glycol, and more particularly, to a process for producing a polyalkylene terephthalate glycol resin having a high viscosity and excellent color fast during a process time.

The polyalkylene terephthalate resin is a polyester resin which is produced by using terephthalic acid (TPA) or dimethyl terephthalate (DMT) as an acid raw material and an alkylene diol compound as an alcohol component Refers to a polymer compound produced by an esterification reaction and a polymer polymerization reaction under a catalyst.

Until the 1980s, DMT was mainly used as an acid raw material for quality problems. However, TPA is currently used worldwide except in special fields due to yield control.

The polyalkylene terephthalate resin may be selected from the group consisting of polyethylene terephthalate (PET) resin, polytrimethylene terephthalate (PTT) resin, polybutylene terephthalate (PBT) resin, polycyclohexylenedimethylene terephthalate (PCT) resin, and the like.

In the PET resin, ethylene glycol is used as an alcohol component (diol), 1,3-propanediol is used as an alcohol component (diol) in a PTT resin, and PBT resin is an alcohol component (1,4-butanediol) is used as the alcohol component (diol) and 1,4-cyclohexane dimethanol (CHDM) is used as the alcohol component (diol) do.

These polyalkylene terephthalate resins are widely used in everyday life such as fibers, films, and bottles because they have excellent physical properties such as heat resistance, transparency, strength, processability and the like compared with polymer resins such as PP and PE.

The polyalkylene terephthalate resin generally has a form of homopolymer composed of a single alcohol component. However, depending on the alcohol component, the physical properties such as the melting point, crystallization degree, heat resistance and strength of the polymer resin differ, Depending on the physical properties, a polyester copolymer having three or more diols as an alcohol raw material or three or more homopolymers may be blended together.

PET, which is most widely used as a polyalkylene terephthalate resin, has excellent physical properties and is widely used in various fields such as fibers, bottles, films, etc. However, since it has a somewhat weak physical property for use as a high strength plastic or high function plastic, There was a problem that did not last long. Therefore, glass bottles have been used for applications requiring stronger physical properties than PET, such as beverage bottles and seasoning bottles. Glass bottles are heavy in weight and difficult to transport, and are frequently broken by collision during transportation, There is a problem that there is a high possibility of entering into the body due to an invisible glass powder.

To overcome this problem, polyethylene terephthalate glycol (PETG) resin has been developed. PETG resin is made of amorphous resin by adding glycol to PET. It is transparent as glass, and has high strength property. It is expected to be a high-strength, high-functional plastic that can replace PET and glass. PETG resin has been widely used in food containers, soundproof walls, beverage bottles, etc. Recently, the use of PETG resin as a cosmetic container in Korea and China has widened the scope of application, and consumers' interest is increasing.

The production method of PETG is described in Korean Patent Registration No. 10-0838321, Publication No. 10-2013-0076733, etc. In the above documents, PETG resin is described on the same line as a general polyester- It is inadequate to produce a PETG resin which requires a much higher viscosity than a general PET resin. For example, in the case of PET, it is possible to increase the viscosity by increasing the intrinsic viscosity (viscosity) by solid phase polymerization if the viscosity is not increased any more. However, PETG is difficult to be solid- .

Under such circumstances, the inventors of the present invention have found a method for producing a high-viscosity PETG resin which is transparent and improved in reactivity in a simple process in a short time, and completed the present invention.

Disclosure of the Invention An object of the present invention is to solve the above-mentioned problems, and to provide a method of producing a high viscosity PETG resin which is transparent even under a simple process and process conditions and has improved reactivity, at a high processing time.

In order to solve the above problems, the present invention relates to a method for producing a polymer electrolyte membrane, comprising: adding a slurry containing a dicarboxylic acid, an alcohol, a catalyst and a stabilizer to a monomer reactor and heating to perform a monomer reaction; And transferring the product of the monomer reaction to a polymer reactor to carry out a polymerization reaction, wherein 35 to 65% by weight of the monomer reaction product is transferred to a polymer reactor, And further adding the slurry to the remaining amount to perform a monomer reaction. The polyalkylene terephthalate glycol according to the present invention can be produced by reacting a polyalkylene terephthalate glycol.

In the present invention, the polyalkylene terephthalate glycol may be polyethylene terephthalate glycol (PETG).

In the present invention, the dicarboxylic acid and the alcohol may be added in a molar ratio of 1: 1.05 to 1: 2.5.

In the present invention, the dicarboxylic acid is preferably selected from the group consisting of dimethyl terephthalate (DMT), terephthalic acid (TPA), isophthalic acid, naphthalene dicarboxylic acid (NDA) Derivatives thereof.

In the present invention, the alcohol is selected from the group consisting of ethylene glycol (EG), 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM ), 1,6-hexanediol and trimethylol propane (TMP). Preferably, the polyhydric alcohol may be at least one selected from the group consisting of 50 to 90 mol% of ethylene glycol, , And 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM), 1,6-hexanediol, And 10 to 50 mol% of at least one polyhydric alcohol selected from the group consisting of trimethylol propane (TMP).

In the present invention, the alcohol may include trimethylolpropane (TMP) in an amount of 0.1 to 1.5 mol% of the total alcohol.

In the present invention, the catalyst may be at least one selected from the group consisting of acetaldehyde, acetaldehyde, Propyl titanate, tetra-n-propyl titanate, titanium oxide, tetrabutyl titanate, and titanium chelate compounds.

In the present invention, the catalyst may be added in an amount of 20 to 800 ppm based on the weight of the total reactants.

In the present invention, the stabilizer may be selected from the group consisting of trimethylphosphate, triethylphosphate, neopentyldiaryloxytryphosphate, triphenylphosphate, triethylphosphonoacetate, phosphoric acid, And phosphorous acid. [0027]

In the present invention, the stabilizer may be added in an amount of 30 to 600 ppm based on the weight of the total reactants.

In the present invention, the monomer reaction may be carried out such that the reaction temperature is raised to 5 to 7 ° C / min and the final reaction temperature is 220 to 250 ° C.

In the present invention, the polymerization reaction may be carried out at 250 to 280 ° C, and the vacuum may be applied for 30 to 40 minutes.

The production method of the present invention can be carried out in a state where oxygen is blocked.

The present invention also provides a polyalkylene terephthalate glycol produced by the above process.

In the present invention, the polyalkylene terephthalate glycol is preferably polyethylene terephthalate glycol (PETG).

In the present invention, the polyalkylene terephthalate glycol may have an intrinsic viscosity of 0.5 to 1.2 dl / g, a color coordinate L ^* value of 65 or more, and a b ^* value of 6 or less.

The process for producing polyalkylene terephthalate glycol according to the present invention is a resin in which glycols are added to PET used in conventional fibers, bottles, films, etc., and can produce a highly functional plastic having a very high intrinsic viscosity and a transparent color such as glass have.

In addition, the production method of the present invention is characterized in that a polyalkylene terephthalate glycol resin having a high intrinsic viscosity and a good color is obtained by transferring half of a monomer reaction product to a polymer reactor and adding a reactant slurry to the remaining amount to perform a monomer reaction Can be produced in a short reaction time.

1 shows the chemical structure of the polyethylene terephthalate glycol produced by the present invention.
2 is a schematic diagram of the inner section of the Ubbelodhe viscosity tube.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description is merely for a better understanding of the embodiments of the present invention and is not intended to limit the scope of protection.

The present invention relates to a method for producing a polyalkylene terephthalate glycol resin having high viscosity and high transparency and high strength in a short time by a simple process.

In a preferred embodiment of the present invention, the polyalkylene terephthalate glycol is polyethylene terephthalate glycol (PETG). The chemical structure of the PETG is shown in Fig.

In the PETG, glycol is added to the existing PET to make an amorphous resin so that haze is not generated, and thus a transparent high strength resin can be produced.

Specifically, the high-functionality polyalkylene terephthalate glycol resin according to the present invention can be produced by the following method:

Adding a slurry comprising a dicarboxylic acid, an alcohol, a catalyst and a stabilizer to a monomer reactor and heating to perform a monomer reaction; And

And transferring the product of the monomer reaction to a polymer reactor to perform a polymerization reaction.

Hereinafter, the production method of the present invention will be described in detail with PETG resin, which is a preferred embodiment of the present invention, as an example.

Dicarboxylic acid and alcohol

The dicarboxylic acid may be an aromatic dicarboxylic acid such as dimethyl terephthalate (DMT), terephthalic acid (TPA), isophthalic acid, naphthalene dicarboxylic acid (NDA) It is preferable to use derivatives thereof, and it is most preferable to use at least one of DMT and TPA to produce high-performance PETG, and TPA is most preferable in terms of viscosity and color.

The alcohol may be selected from the group consisting of ethylene glycol (EG), 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM), 1,6 It is preferable to use a combination of two or more kinds of polyhydric alcohols such as 1,6-hexanediol and trimethylol propane (TMP).

In the present invention, the alcohol component may be selected from the group consisting of 50 to 90 mol% of ethylene glycol, and 1, 4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, More preferably at least 10 mol% of at least one polyhydric alcohol selected from the group consisting of CHDM, 1,6-hexanediol and trimethylol propane (TMP) . As preferred polyhydric alcohols, alicyclic diols can be used to form cyclic repeating units in the main chain, and 1,4-cyclohexane dimethanol (CHDM) is particularly preferably used.

In addition, in order to obtain an improved reactivity and a high viscosity, it is important to introduce a polyhydric alcohol capable of producing a transparent resin without impairing the functionality. As such a polyhydric alcohol, trimethylol propane (TMP) is preferably added in an amount of 0.1 to 1.5 mol% of the total alcohol.

The dicarboxylic acid and the alcohol are preferably used in a molar ratio of 1: 1.05 to 1: 2.5. If the molar ratio is 1: 1.05 or less, the excess amount of the alcohol is too small to synthesize the polymer. If the molar ratio is 1: 2.5 or more, the effect on the cost is large and the production cost is burdensome.

Catalyst and stabilizer

It is also important to select catalysts and stabilizers in order to obtain transparent and highly viscous resins.

Examples of the catalyst that can be used in the present invention include at least one member selected from the group consisting of acetates, acetals, acetocobalt, acetomanganese, dibutyl tin oxide, butyl-isopropyl titanate, tetra-isopropyl titanate, Propyl titanate, tetra-n-propyl titanate, titanium oxide, tetrabutyl titanate and titanium chelate compounds are preferable, and it is more preferable to use two kinds of catalysts in a molar ratio of 9: 1 to 8: 2 Do.

It is preferable that the catalyst is added in an amount of 20 to 800 ppm based on the weight of the whole reactant for stable polymer polymerization. If the amount of the catalyst is less than 20 ppm, the effect is insignificant and the polymerization reaction does not proceed well and the polymer is difficult to become a polymer. If the amount is 800 ppm or more, the color of the produced PETG may be deteriorated.

As the stabilizer usable in the present invention, stabilizers used in general polyester polymerization reaction can be used, but more preferably, trimethylphosphate, triethylphosphate, neopentyldiaryloxytrilephosphate, triphenyl It is preferable to use a stabilizer such as triphenylphosphate, triethylphosphonoacetate, phosphoric acid, or phosphorous acid singly or in combination.

Preferably, the stabilizer is added in an amount of 30 to 600 ppm of the total reaction product. If the stabilizer content is less than 30 ppm, the color of the PETG may deteriorate. If the stabilizer content is more than 600 ppm, the reaction time may become long, and the productivity may be deteriorated. If the stabilizer content is too high, it is difficult to obtain a polymer having a high molecular weight.

Reaction process

The method for producing PETG according to the present invention comprises a first step of adding a slurry containing a dicarboxylic acid, an alcohol, a catalyst and a stabilizer to a monomer reactor to perform an esterification reaction, and a step of subjecting the esterified product to a polymer reactor And a second step of carrying out the polymerization reaction.

The monomer reaction as the first reaction is preferably carried out while raising the temperature to about 5 to 7 ° C per minute after the start. By-products start to emerge at temperatures in the reactor between 160 and 180 ° C. The by-products are mainly methanol or water. The initial point is when the temperature of the distillation tower rises and the first drop of by-product drops. If the initial point time is within 20 minutes after the start of the reaction, the temperature may rise too sharply and the monomer may be scattered. If the initial point time exceeds 50 minutes, the reaction time becomes longer and the color of the resin deteriorates.

It is preferable that the reaction is continued after the initial point so that the final reaction temperature is 220 to 250 ° C. The monomer reaction time is preferably 120 to 240 minutes. It is preferred that the product produced through the monomer reaction has a COOH acid value of between 100 and 800.

As described above, DMT or TPA is used as the polyester reaction, and TPA is preferably used. The disadvantage of TPA is that the reaction is slow due to poor melting of alcohol such as ethylene glycol, .

In the present invention, in order to solve this problem, the reaction of the monomer reaction (ester reaction) as the first reaction is doubled and the reaction is carried out. 25 to 75% by weight of the reaction product is transferred to the polymer reactor, The monomer, the carboxylic acid, the carboxylic acid, the carboxylic acid, the carboxylic acid, the alcohol, the catalyst, the stabilizer, etc.) The amount of reaction product transferred to the polymer reactor is more preferably 35 to 65 wt%, most preferably 45 to 55 wt% of the total product.

In general, when the monomer product is added to the polymer reactor at a time to carry out the reaction, the monomer reaction takes about 6 to 8 hours from the start to the end. On the other hand, when the monomer product is transferred to the polymer reactor only by 35 to 65 wt% and the remainder is mixed with the reactant slurry to perform the monomer reaction again, the overall reaction time is significantly reduced to about 3 to 4 hours. Such reduction of the reaction time facilitates color management of the resin, and can be attributed to productivity improvement and production cost reduction.

The reactant (monomer) transferred to the polymer reactor is heated again to proceed the polymerization reaction. The polymerization reaction is preferably carried out at a temperature of from 240 to 260 ° C, and the polymerization reaction is allowed to proceed at 250 to 280 ° C.

Once stabilized to a certain extent, vacuuming the reactor to remove the by-products from the reactor as soon as possible is desirable to facilitate the polymerisation. At this time, the vacuum is preferably applied gradually for 30 to 40 minutes. If the vacuum is applied too quickly, the monomer or oligomer may spill into the condenser. In such a case, if the vacuum line is clogged and the degree of vacuum is lowered, the polymerization may be difficult, and the molar ratio of the dicarboxylic acid and the alcohol may not match due to scattering of the unreacted material. For example, by applying a program such that the pressure drops from 760 mmHg to 10 mmHg for 30 to 40 minutes, a vacuum can be precisely applied to prevent the scattering of the monomer or oligomer. After the pressure drops to 10 mmgHg, it is preferable to apply a pressure drop from 10 mmHg to 0.1 mmHg again for about 15 minutes in order to prevent scattering to the maximum.

As the polymerization progresses, the power value increases due to the viscosity load due to the increase of the polymer, and when the power value is not increased any more, if hunting occurs, the polymer is quickly changed to reduce the stirring speed to induce the viscosity to increase again. The reason for this is that when the polymer is dried in the agitator, the viscosity does not increase any more, but rather depolymerization occurs and the viscosity decreases. The resin having the desired viscosity can be produced by terminating the reaction by raising the maximum viscosity.

In the present invention, in order to make the hue of the PETG resin more transparent, various reaction conditions such as catalyst, stabilizer, reaction temperature, stirring, and reactor should be considered.

Oxygen interception is preferably carried out in all steps including the addition of the reactants in the reactor to the monomer reactor, the transfer of the monomer to the polymer reactor after the monomer reaction, the polymerization reaction and the discharge of the product. From this point of view, it is preferable to use nitrogen for the vacuum breakdown and discharge pressure. By shutting off the oxygen in the whole process, it is possible to prevent the oxidation of the reactants and to prevent the fire caused by the gas which may occur during the reaction.

In the present invention, although the reaction process is basically described based on batch polymerization, it is advantageous to produce by continuous polymerization when it is applied to a mass production facility. Although the continuous polymerization process is advantageous when producing more than 200 tons per year, the batch process is more advantageous when produced below 200 tons.

Properties of resin

The PETG resin produced by the process according to the present invention preferably has an intrinsic viscosity of 0.4 to 1.2 dl / g, preferably 0.65 to 0.90 dl / g. This is a remarkably high level as compared with that of an ordinary PET resin having an intrinsic viscosity of about 0.6 to 0.65 dl / g. When such an intrinsic viscosity is secured, a resin having transparency like glass and high strength can be obtained.

Also, PETG resin according to the present invention it is more preferred that the L ^* value of the color coordinate 65 or more, b ^* values, it is preferable with a value of 6 or less, L ^* value is 70 or higher, b ^* value is less than or equal to 5.

Usage

Since the PETG resin according to the present invention is transparent like glass and has a very high strength, it is suitably applied to food containers, kimchi refrigerator kimchi containers, cosmetic containers, 3D printer resins, tooth related resins and the like.

Especially, the resins used in 3D printers currently use polylactic acid (PLA), which is known as eco-friendly resin made from grains, and PLA is broken. To overcome this problem, acrylonitrile butadiene styrene (ABS) resin has been proposed. However, considering that ABS resin dissolves during 3D printing and harmful gas is generated, considering that most 3D printing work takes place in a narrow space, There is a risk of harming the human body.

Since the PETG resin according to the present invention is transparent and has a high viscosity and does not emit harmful gas to the human body, it can be used in 3D printer instead of the PLA or ABS resin, and the branding of environmentally friendly PLA resin and PETG resin is used It is also possible to do.

In addition, the PETG resin according to the present invention is transparent and has high strength, so that the PETG resin can also be used for dental implant or dental mouthpiece.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. It will be apparent to those skilled in the art that these embodiments are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

How to measure intrinsic viscosity

The PETG resin of the examples and comparative examples was dissolved in o-chlorophenol at a concentration of 1.2 g / dl and the intrinsic viscosity was measured using a Ubbelodhe viscometer.

The internal temperature of the viscosity tube is maintained at 35 DEG C, and the time taken for the solution to pass between the sections a - b in the viscosity tube as shown in Fig. 2 is t, When the time (Efflux time) is t ₀ , the specific viscosity and intrinsic viscosity are defined as follows.

* Boiling point

(Where t is the time required for the solvent to pass through the viscometer internal constant interval, and t ₀ is the time at which the solution passes through the same section)

* Intrinsic viscosity

(Where A is 0.247 as a Huggins constant and c is 1.2 dl / g as a concentration value)

Example 1

(1.55 gmol) of ethylene glycol (EG), 94 g (0.653 gmol) of 1,4-cyclohexanedimethanol (CHDM) and 3 g (0.022 gmol) of trimethylolpropane (TMP) ), 0.1 g of tetrabutyl titanate (TBT), 0.04 g of titanium dioxide (TiO ₂ ), 0.15 g of phosphoric acid (PA) and 0.04 g of trimethyl phosphate (TM) were prepared.

DMT was added to the esterification reactor and EG, CHDM and TMP were added to the reactor in about half of the metered amount. Catalysts (TBT and TiO ₂ ) and stabilizers (Pa, TM) were then added in sequence, and the remaining half of the alcohol was added to the inlet and the stirrer in an as-washed state. Nitrogen was flowed finely after the feedstock was poured, and the reactor lid was closed well and then nitrogen was flowed once again.

Nitrogen purging was performed for about 1 minute and then the reaction was started by heating. The temperature of the reactor was increased by 5 ~ 7 ℃ / min to induce the esterification reaction of the reactants. The initial point was controlled between 30 and 40 minutes, and the maximum temperature was controlled by 240 ° C.

In order to transfer half of the monomer to the polymer reactor, a siphon tube was pushed to the reactor 2/3 below the ceiling, and a monomer placed on the siphon tube was transferred to a polymerization autoclave (PA) under a nitrogen pressure.

After transferring half of the product, the esterification reactor was charged with the slurry containing the reactants and the monomer reaction was carried out again. The maximum temperature was adjusted to 240 ° C, and the reaction time until completion of the byproducts was checked. As a result, it was confirmed that the monomer reaction was carried out for 220 minutes.

The monomer transferred to the polymer reactor was subjected to a polymerization reaction by raising the reaction temperature to 250 ° C. The vacuum degree was set to 0.01 torr, vacuum reaction was carried out for about 140 minutes, and the PETG resin was produced by discharging.

The reaction conditions and physical properties of the produced PETG are shown in Table 1 below.

Examples 2 to 5

PETG resin was prepared by the same procedure as in Example 1, except that the composition of the dicarboxylic acid and alcohol and the reaction temperature were changed to those shown in Table 1.

Comparative Examples 1 to 5

PETG was prepared according to the composition and reaction conditions shown in Table 1 below. After the monomer reaction, the entire product was transferred to a polymer reactor to carry out a polymerization reaction to prepare a PETG resin.

In Table 1 above, it can be seen that the monomer reaction times were completed faster in Examples 4 and 5 using TPA than in Examples 1 to 3 using DMT as the dicarboxylic acid.

In addition, the process of the example in which one half of the monomer product was transferred to the polymer reactor and the reactant slurry was added to perform the monomer reaction showed a much faster monomer reaction rate than the process of the comparative example in which the entire monomer product was transferred to the polymer reactor It was confirmed that a PETG resin having an intrinsic viscosity and a color of similar or superior level could be produced.

Claims (19)

Adding a slurry comprising a dicarboxylic acid, an alcohol, a catalyst and a stabilizer to a monomer reactor and heating to perform a monomer reaction; And
And transferring the product of the monomer reaction to a polymer reactor to perform a polymerization reaction, wherein the polyalkylene terephthalate glycol,
Wherein the monomer reaction is carried out by transferring 35 to 65% by weight of the monomer reaction product to the polymer reactor and further adding the slurry to the remaining amount to perform a monomer reaction. .
The method according to claim 1,
Wherein the polyalkylene terephthalate glycol is polyethylene terephthalate glycol (PETG). ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the dicarboxylic acid and the alcohol are added in a molar ratio of 1: 1.05 to 1: 2.5.
The method according to claim 1,
Wherein the dicarboxylic acid is selected from the group consisting of dimethyl terephthalate (DMT), terephthalic acid (TPA), isophthalic acid, naphthalene dicarboxylic acid (NDA) Lt; RTI ID = 0.0 > polyalkylene terephthalate < / RTI > glycol.
The method according to claim 1,
The alcohol may be selected from the group consisting of ethylene glycol (EG), 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM), 1,6 Wherein the polyalkylene terephthalate glycol is at least two polyhydric alcohols selected from the group consisting of 1,6-hexanediol and trimethylol propane (TMP).
6. The method of claim 5,
Wherein the alcohol is selected from the group consisting of 50 to 90 mol% of ethylene glycol and 1, 4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM) Characterized in that it comprises 10 to 50 mol% of at least one polyhydric alcohol selected from the group consisting of 1,6-hexanediol and trimethylol propane (TMP). The polyalkylene terephthalate glycol Way.
6. The method of claim 5,
Wherein the alcohol comprises trimethylolpropane (TMP) in an amount of 0.1 to 1.5 mol% of the total alcohol.
The method according to claim 1,
Wherein the catalyst is selected from the group consisting of acetates, acetals, acetocobalt, acetamanganese, dibutyl tin oxide, butyl-isopropyl titanate, tetra-isopropyl titanate, tetra- -n-propyl titanate, titanium oxide, tetrabutyl titanate, and titanium chelate compound. 3. The polyalkylene terephthalate glycol according to claim 1, wherein the polyalkylene terephthalate glycol is at least one selected from the group consisting of n-propyl titanate, titanium oxide,
The method according to claim 1,
Wherein the catalyst is added in an amount of 20 to 800 ppm based on the weight of the total reactant.
The method according to claim 1,
Wherein the stabilizer is selected from the group consisting of trimethylphosphate, triethylphosphate, neopentyldiaryloxytrilephosphate, triphenylphosphate, triethylphosphonoacetate, phosphoric acid and phosphorous acid ), Wherein the polyalkylene terephthalate glycol is at least one selected from the group consisting of polyalkylene terephthalate glycols.
The method according to claim 1,
Characterized in that the stabilizer is added in an amount of 30 to 600 ppm based on the weight of the total reactant.
The method according to claim 1,
Wherein the monomer reaction is carried out such that the reaction temperature is raised to 5 to 7 ° C / min to obtain a final reaction temperature of 220 to 250 ° C.
The method according to claim 1,
Characterized in that the polymerization reaction is carried out at 250 to < RTI ID = 0.0 > 280 C. < / RTI >
The method according to claim 1,
Characterized in that the polymerization is carried out by applying a vacuum over 30 to 40 minutes.
The method according to claim 1,
Characterized in that the reaction is carried out in the oxygen-free state.
A polyalkylene terephthalate glycol produced by the process of any one of claims 1 to 15.
17. The method of claim 16,
Wherein the polyalkylene terephthalate glycol is polyethylene terephthalate glycol (PETG).
17. The method of claim 16,
0.0 > dl / g. ≪ / RTI > The polyalkylene terephthalate glycol has an intrinsic viscosity of from 0.5 to 1.2 dl / g.
17. The method of claim 16,
A polyalkylene terephthalate glycol having a color coordinate L ^* value of 65 or more and a b ^* value of 6 or less.

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