HK1220712B

HK1220712B - Polyester based copolymer resin and molded product comprising the same

Info

Publication number: HK1220712B
Application number: HK16108836.3A
Authority: HK
Inventors: 林雪熙; 金圣基
Original assignee: Sk化学株式会社
Priority date: 2013-05-02
Filing date: 2014-04-30
Publication date: 2018-04-27

Abstract

The present invention relates to a copolymerized polyester resin having a superior shrinkage rate and capable of thermal shrinkage at low temperatures, and a molded product using the same. The copolymerized polyester resin, according to one aspect of the present invention, comprises: a dicarboxylic acid-derived residue of a residue derived from an aromatic dicarboxylic acid; a residue derived from a predetermined 4-(hydroxymethyl) cyclohexylmethyl 4'-(hydroxymethyl) cyclohexane carboxylate; and a diol-derived residue of a residue derived from a predetermined 4,4-(oxybis(methylene)bis) cyclohexane methanol.

Description

Polyester-based copolymer resin and molded product comprising the same

Technical Field

The present invention relates to a polyester-based copolymer resin and a molded product comprising the same, and more particularly, to a polyester-based copolymer resin capable of having an excellent shrinkage rate and thermally shrinking at a low temperature, and a molded product comprising the same.

Background

Heat-shrinkable plastic products utilize the property of being shrunk by heating and are widely used as films for shrink wrapping, shrink labels, or the like. Among them, polyvinyl chloride (PVC), polystyrene and polyester-based plastic films have been used as labels or sealing caps for various containers or as direct packing materials or the like.

However, the film made of polyvinyl chloride is a pipe product because materials generating hydrogen chloride and dioxin may be generated when the film is burned. Further, when this product is used as a shrink label for a polyethylene terephthalate (PET) container or the like, a troublesome process of separating the label and the container should be performed when the container is reused.

Further, in the polystyrene-based film, stability depending on the work of the shrinking process may be excellent and the appearance of the product may be good, but chemical resistance may not be excellent, so that there is a problem in printing that an ink having a specific composition should be used. Further, the polystyrene-based film has a disadvantage in that the film may spontaneously shrink because of insufficient storage stability at room temperature, so that its size may be changed.

In order to solve the above-mentioned problems, a film made of a polyester resin has been researched and developed as a film capable of replacing a film made of the above-mentioned two raw materials. Meanwhile, as the usage amount of PET containers increases, the usage amount of polyester film capable of being easily reused without separately separating labels upon repeated use has been gradually increased, but the heat-shrinkable polyester film according to the related art has a problem with respect to shrinkage characteristics. That is, there is a problem in that wrinkling or uneven shrinkage upon shrinkage frequently occurs during molding due to rapid changes in shrinkage behavior. In addition, since the shrinkage property of the polyester film is reduced at a low temperature as compared to a polyvinyl chloride-based film or a polystyrene-based film in order to compensate for this disadvantage, the polyester film should be shrunk at a high temperature. In this case, there is a problem in that the PET container may be deformed, or a white turbidity phenomenon (also referred to as haze) may be generated.

Therefore, research into polyester-based copolymer resins capable of having excellent shrinkage and improving shrinkage properties at low temperatures is required.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

The present invention seeks to provide a polyester-based copolymer resin capable of having an excellent shrinkage rate and thermally shrinking at low temperatures.

[ technical solution ] A

An exemplary embodiment of the present invention provides a polyester-based copolymer resin comprising: dicarboxylic acid derived residues including residues derived from aromatic dicarboxylic acids; and a diol derivative residue including a residue derived from 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by the following chemical formula 1 and a residue derived from 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by the following chemical formula 2

[ chemical formula 1]

[ chemical formula 2]

Further, the diol-derived residues may also include residues derived from 1, 4-cyclohexanedimethanol, diethylene glycol, and ethylene glycol.

Further, the aromatic dicarboxylic acid may be one or more selected from the group consisting of: terephthalic acid, dimethyl terephthalate, cycloaliphatic dicarboxylic acids, isophthalic acid, adipic acid, azelaic acid, naphthalenedicarboxylic acid, and succinic acid.

Another exemplary embodiment of the present invention provides a method for preparing a polyester-based copolymer resin, the method including: a dicarboxylic acid including an aromatic dicarboxylic acid is reacted with a diol including 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by chemical formula 1 and 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by chemical formula 2 to perform an esterification reaction and a polycondensation reaction.

Further, the diols may also include 1, 4-cyclohexanedimethanol, diethylene glycol, and ethylene glycol.

The diol may include 0.1 to 5 mol% of 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, 0.1 to 12 mol% of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 0.1 to 15 mol% of 1, 4-cyclohexanedimethanol, 2 to 15 mol% of diethylene glycol, and 53 to 97.7 mol% of ethylene glycol, based on 100 mol% of the dicarboxylic acid.

After the diol is injected in a molar ratio of 1.2 to 3.0 with respect to the dicarboxylic acid, the esterification reaction may be carried out at a reaction temperature of 230 ℃ to 265 ℃ and 1.0kg/cm²To 3.0kg/cm²Pressure ofThe force is applied for a period of 100 to 300 minutes.

Further, in the polycondensation reaction, additives including a polycondensation catalyst, a stabilizer, and a colorant may be used.

Meanwhile, the polycondensation reaction may be performed at a reaction temperature of 260 to 290 ℃ and under reduced pressure of 400 to 0.1 mmHg.

Another exemplary embodiment of the present invention provides a molded product comprising the polyester-based copolymer resin as described above, and the molded product may be a heat shrinkable film.

[ PROBLEMS ] the present invention

The polyester-based copolymer resin according to the present invention and a molded product such as a heat shrinkable film or the like comprising the same may have an excellent shrinkage rate and may be heat-shrinkable at a low temperature, similar to PVC, compared to the polyester-based copolymer resin according to the related art, thereby being capable of preventing deformation or a white turbidity phenomenon (also referred to as haze) of a PET container caused during heat shrinkage of the film. Further, since the shrinkage speed can be easily adjusted, molding defects can be reduced.

Best mode for carrying out the invention

The present invention may be variously modified and have various types, and specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the exemplary embodiments described herein, but all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention are also included in the present invention. Further, when it is determined that detailed description on known technologies of the present invention may obscure the gist of the present invention, the detailed description thereof will be omitted.

According to an aspect of the present invention, there is provided a polyester-based copolymer resin comprising: dicarboxylic acid derived residues including residues derived from aromatic dicarboxylic acids; and a diol derivative residue including a residue derived from 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by the following chemical formula 1 and a residue derived from 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by the following chemical formula 2

[ chemical formula 1]

[ chemical formula 2]

Further, according to another aspect of the present invention, a method for preparing a polyester-based copolymer resin, the method comprising: a dicarboxylic acid including an aromatic dicarboxylic acid is reacted with a diol including 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by chemical formula 1 and 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by chemical formula 2 to perform an esterification reaction and a polycondensation reaction.

Further, according to another aspect of the present invention, there is provided a molded product comprising the polyester-based copolymer resin as described above.

Hereinafter, the polyester-based copolymer resin according to an exemplary embodiment of the present invention will be described in more detail.

As used herein, the term 'residue' means a predetermined moiety or unit that is included in the product of a chemical reaction and is derived from a particular compound when the particular compound participates in the chemical reaction. For example, 'dicarboxylic acid-derived residue' and 'diol-derived residue' mean moieties derived from a dicarboxylic acid component and a diol component in a polyester formed by esterification reaction or polycondensation reaction, respectively.

The polyester-based copolymer resin according to an exemplary embodiment of the present invention includes: dicarboxylic acid derived residues including residues derived from aromatic dicarboxylic acids; and a diol derivative residue including a residue derived from 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by the following chemical formula 1 and a residue derived from 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by the following chemical formula 2.

In the polyester film according to the related art, there is a problem in that wrinkling or uneven shrinkage when shrinkage frequently occurs during molding due to rapid changes in shrinkage behavior. In addition, since the shrinkage property of the polyester film is reduced at a low temperature as compared to a polyvinyl chloride-based film or a polystyrene-based film in order to compensate for this disadvantage, the polyester film should be shrunk at a high temperature. In this case, there is a problem in that the PET container may be deformed, or a white turbidity phenomenon (also referred to as haze) may be generated.

Therefore, the present inventors determined through experiments that: in the case of providing a polyester-based copolymer resin prepared using a diol comprising 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate and 4,4- (oxybis (methylene) bis) cyclohexanemethanol, and a molded product such as a heat shrinkable film comprising the polyester-based copolymer resin, shrinkage is excellent, the film can be heat-shrunk at a low temperature, deformation and a white turbidity phenomenon (also referred to as haze) of a PET container caused during heat shrinkage of the film can be prevented, similar to PVC, and molding defects can be reduced because the shrinkage speed can be easily adjusted, thereby completing the present invention.

As the diol compound used for improving moldability or other physical properties of a polymer prepared from terephthalic acid, diethylene glycol and ethylene glycol, there are 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, 4- (oxybis (methylene) bis) cyclohexanemethanol, 1, 4-cyclohexanedimethanol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 2-dimethyl-1, 3-propanediol, 1, 6-hexanediol, 1, 2-cyclohexanediol, 1, 4-cyclohexanediol, 1, 2-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, and the like. In particular, as the diol compound used for improving the physical properties of the polymer, 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, 4- (oxybis (methylene) bis) cyclohexanemethanol are preferable. The reason is that in the case of using 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate and 4,4- (oxybis (methylene) bis) cyclohexanemethanol, since the molecular chain length at a predetermined level or more related to the residual stress increases as compared with the case of using the above-mentioned compound, the residual stress depending on the stretching may increase, so that the shrinkage force may increase according to the residual stress relaxation upon heat supply.

4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate is represented by the following chemical formula 1, and 4,4- (oxybis (methylene) bis) cyclohexanemethanol is represented by the following chemical formula 2

[ chemical formula 1]

[ chemical formula 2]

The amounts of 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate and 4,4- (oxybis (methylene) bis) cyclohexanemethanol used in the present invention are close to the desired mol% in the final polymer. In order to prevent moldability defects depending on crystallization, it is preferable to use the amount of 2 to 17 mol% based on the entire diol component. The reason is that, in the case where the amount used is less than 2 mol%, it is difficult to determine the effect of improving the shrinkage rate, and in the case where the amount used is more than 17 mol%, a white turbidity phenomenon (also referred to as haze) may be generated due to excessive stretching, so that the practicability of the polyester-based copolymer resin as a raw material for a heat shrinkable film becomes poor.

The method for preparing a polyester-based copolymer resin according to another aspect of the present invention may include: a dicarboxylic acid including an aromatic dicarboxylic acid is reacted with a diol including 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by chemical formula 1 and 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by chemical formula 2 to perform an esterification reaction and a polycondensation reaction.

In addition, the diols may also include 1, 4-cyclohexanedimethanol, diethylene glycol, and ethylene glycol. That is, the diol may include 0.1 to 5 mol% of 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, 0.1 to 12 mol% of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 0.1 to 15 mol% of 1, 4-cyclohexanedimethanol, 2 to 15 mol% of diethylene glycol, and 53 to 97.7 mol% of ethylene glycol, based on 100 mol% of dicarboxylic acid.

The polyester-based copolymer resin according to the present invention is prepared through an esterification reaction and a polycondensation reaction. The esterification reaction corresponding to the first step may be carried out in batches or continuously, and each raw material may be injected separately, but preferably, the dicarboxylic acid may be injected into the diol in the form of slurry.

Further, after injecting the diol in a molar ratio of 1.2 to 3.0 with respect to the dicarboxylic acid, the esterification reaction is carried out at a reaction temperature of 230 ℃ to 265 ℃, more preferably 245 ℃ to 255 ℃ and 1.0kg/cm²To 3.0kg/cm²Under pressure of (c). Further, the reaction time of the esterification reaction may be generally about 100 to 300 minutes, but is not limited thereto because the reaction time may be suitably changed according to the reaction temperature, pressure, and molar ratio of ethylene glycol to dicarboxylic acid used.

Meanwhile, the esterification reaction does not require a catalyst, but the catalyst may be selectively injected in order to reduce the reaction time.

After the above-mentioned esterification reaction is completed, a polycondensation reaction is performed, and a polycondensation catalyst, a stabilizer, a colorant, and the like may be selectively used as components generally used in the polycondensation reaction of a polyester resin.

As the polycondensation catalyst usable in the present invention, there are compounds of titanium, germanium and antimony, and the like, but the present invention is not particularly limited thereto.

The titanium-based catalyst, as a catalyst used as a polycondensation catalyst for a polyester resin in which a cyclohexanedimethanol-based derivative is copolymerized in a proportion of 15% or more based on the weight of terephthalic acid, has advantages in that a polycondensation reaction can be performed even with a small amount of the titanium-based catalyst compared to an antimony-based catalyst, and the titanium-based catalyst is less expensive than a germanium-based catalyst.

More specifically, as the titanium-based catalyst that can be used, there are tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate, 2-ethylhexyl titanate, octylglycol titanate, lactic acid titanate, triethanolamine titanate, acetylacetonato titanate, ethylacetoacetate titanate, isostearic acid titanate, titanium dioxide, coprecipitate of titanium dioxide and silicon dioxide, coprecipitate of titanium dioxide and zirconium dioxide, and the like.

In this case, since the used amount of the polycondensation catalyst affects the color of the final polymer, the used amount may vary depending on the desired color, the used stabilizer, and the used colorant, but the used amount may preferably be 1ppm to 100ppm, more preferably 1ppm to 50ppm, based on the content of titanium element relative to the weight of the final polymer, and may be 10ppm or less based on the content of silicon element. The reason is that in the case where the content of titanium element is less than 1ppm, it is impossible to achieve a desired degree of polymerization, and in the case where the content is more than 100ppm, the final polymer becomes yellow, so that it is impossible to obtain a desired color.

Further, as other additives, stabilizers, colorants, and the like may be used. As the stabilizer usable in the present invention, there are phosphoric acid, trimethyl phosphate, triethyl phosphonoacetate, and the like, and the addition amount thereof may preferably be 10ppm to 100ppm based on the content of phosphorus element relative to the weight of the final polymer. The reason is that in the case where the amount of the stabilizer added is less than 10ppm, it is difficult to obtain a desired color, and in the case where the amount added is more than 100ppm, it is impossible to achieve a desired high degree of polymerization.

Further, as the colorant usable in the present invention for improving the color, there are cobalt acetate, cobalt propionate and the like, and the addition amount thereof may preferably be 100ppm or less based on the weight of the final polymer. In addition, in addition to the colorant, existing organic compounds known in the art may be used as the colorant.

Meanwhile, the polycondensation reaction performed after the addition of these components may be preferably performed at 260 to 290 ℃ and under reduced pressure of 400 to 0.1mmHg, but is not limited thereto.

The polycondensation step is carried out until the viscosity of the reactants reaches the desired intrinsic viscosity. In this case, the reaction temperature may be generally 260 ℃ to 290 ℃, preferably 260 ℃ to 280 ℃, and more preferably 265 ℃ to 275 ℃.

A molded product according to another aspect of the present invention may include the polyester-based copolymer resin as described above, and may be a heat shrinkable film.

The heat shrinkable film has a shrinkage initiation temperature of 60 ℃ or less, 40 ℃ to 60 ℃, or 50 ℃ to 60 ℃, the maximum heat shrinkage at 60 ℃ may be 4% or more, 4% to 10%, or 5% to 9%, and the maximum shrinkage at 90 ℃ may be 80% or more, 80% to 99%, or 81% to 95%.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, this example is only for illustrating the present invention and is not to be construed as limiting the scope of the present invention.

Example 1

A polyester resin in which 1 mole of 4- (hydroxymethyl) cyclohexanecarboxylic acid, 5 moles of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 1 mole of 1, 4-cyclohexanedimethanol, 10 moles of diethylene glycol and 83 moles of ethylene glycol were copolymerized in 14 moles of terephthalic acid was slowly heated to 255 ℃ while being mixed in a batch reactor (3kg), thereby carrying out a reaction.

In this case, the esterification reaction is carried out by discharging the produced water out of the reactor, and when the production and discharge of water are finished, the contents of the reactor are transferred to a polycondensation reactor equipped with a stirrer, a condenser and a vacuum system.

After 0.5g of tetrabutyltitanate, 0.4g of triethyl phosphate and 0.5g of cobalt acetate were added to the esterification reaction, the reaction was initially carried out under a low vacuum (atmospheric pressure to 50mmHg) for 40 minutes while increasing the internal temperature from 240 ℃ to 275 ℃. Then, the ethylene glycol was removed and the pressure was slowly reduced to 0.01mmHg, so that the reaction was carried out under high vacuum until the desired viscosity was obtained. Thereafter, the product was discharged and cut into a sheet form. A heat shrinkable film is manufactured using the prepared polyester-based copolymer resin.

Example 2

A heat shrinkable film was produced in the same manner as in example 1, except that 2.5 moles of 4- (hydroxymethyl) cyclohexanecarboxylic acid, 11.5 moles of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 1.5 moles of 1, 4-cyclohexanedimethanol, 10 moles of diethylene glycol and 74.5 moles of ethylene glycol were injected based on 14 moles of terephthalic acid.

Example 3

A heat shrinkable film was produced in the same manner as in example 1, except that 2.5 moles of 4- (hydroxymethyl) cyclohexanecarboxylic acid, 8 moles of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 5 moles of 1, 4-cyclohexanedimethanol, 10 moles of diethylene glycol and 74.5 moles of ethylene glycol were injected based on 14 moles of terephthalic acid.

Example 4

A heat shrinkable film was produced in the same manner as in example 1, except that 3 moles of 4- (hydroxymethyl) cyclohexanecarboxylic acid, 4.5 moles of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 7.5 moles of 1, 4-cyclohexanedimethanol, 10 moles of diethylene glycol and 75 moles of ethylene glycol were injected based on 14 moles of terephthalic acid.

Example 5

A heat shrinkable film was produced in the same manner as in example 1, except that 5 moles of 4- (hydroxymethyl) cyclohexanecarboxylic acid, 1 mole of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 10 moles of 1, 4-cyclohexanedimethanol, 10 moles of diethylene glycol and 74 moles of ethylene glycol were injected based on 14 moles of terephthalic acid.

Comparative example 1

A heat shrinkable film was produced in the same manner as in example 1, except that 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate and 4,4- (oxybis (methylene) bis) cyclohexanemethanol were not used.

Comparative example 2

A heat-shrinkable polyester film is prepared using a PVC resin.

Experimental examples

Glass transition temperature, shrinkage initiation temperature, heat shrinkage rate, and intrinsic viscosity of heat shrinkable films prepared using the polyester-based copolymer resins prepared in examples and comparative examples were measured by the following methods, and the results of the measurements are shown in table 1 below.

(1) Glass transition temperature (Tg): the glass transition temperature was measured using a differential scanning calorimeter (TA instruments).

(2) Intrinsic Viscosity (IV): after the prepared polyester-based copolymer resin was dissolved in o-chlorophenol at a concentration of 0.12% at 150 ℃, the intrinsic viscosity was measured at a constant temperature bath of 35 ℃ using an Ubbelohde viscometer.

(3) Heat shrinkage ratio: a sample of the prepared film was cut into a square (10cm x 10cm) and stretched at a stretching ratio (DR) of 1:5 or 1:6(MD: TD) and a stretching speed of 50mm/min to 60mm/min, and then the film was placed in an oven at the temperature shown in table 1 for 40 seconds, thereby being heat-shrunk. Thereafter, the lengths of the sample in the horizontal direction and the vertical direction were measured, and the heat shrinkage rate was calculated by the following equation.

-heat shrinkage (%) 100x (length before shrinkage-length after shrinkage)/(length before shrinkage)

[ Table 1]

As shown in table 1, since the heat shrinkable film made of the polyester-based copolymer resin according to the present invention has a low shrinkage speed due to a low shrinkage initiation temperature, the process can be smoothly controlled so that the defect rate can be reduced and moldability can be excellent. Therefore, a heat shrinkable film product having excellent moldability can be obtained by molding the polyester-based copolymer resin as described above through an extrusion process and a stretching process.

Although the present invention has been described in detail based on the specific features thereof, it is apparent to those skilled in the art that these specific techniques are only preferred embodiments and thus the scope of the present invention is not limited to these embodiments. Accordingly, the substantial scope of the present invention is defined by the appended claims and equivalents thereof.

Claims

1. A polyester-based copolymer resin comprising:

dicarboxylic acid derived residues including residues derived from aromatic dicarboxylic acids; and

diol derived residues including a residue derived from 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by the following chemical formula 1, a residue derived from 4,4- (oxybis (methylene) bis) cyclohexanemethanol represented by the following chemical formula 2, a residue derived from 1, 4-cyclohexanedimethanol, a residue derived from diethylene glycol and a residue derived from ethylene glycol,

wherein the diol derivative residues comprise, based on 100 mole% of dicarboxylic acid, residues derived from 0.1 to 5 mole% of 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, residues derived from 0.1 to 12 mole% of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, residues derived from 0.1 to 15 mole% of 1, 4-cyclohexanedimethanol, residues derived from 2 to 15 mole% of diethylene glycol, and residues derived from 53 to 97.7 mole% of ethylene glycol:

[ chemical formula 1]

[ chemical formula 2]

2. The polyester-based copolymer resin of claim 1, wherein the aromatic dicarboxylic acid is one or more selected from the group consisting of: terephthalic acid, dimethyl terephthalate, isophthalic acid, and naphthalene dicarboxylic acid.

3. A method for preparing a polyester-based copolymer resin, the method comprising: reacting a dicarboxylic acid including an aromatic dicarboxylic acid with a diol including 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate represented by the following chemical formula 1,4- (oxybis (methylene) bis) cyclohexanemethanol represented by the following chemical formula 2, 1, 4-cyclohexanedimethanol, diethylene glycol and ethylene glycol to perform an esterification reaction and a polycondensation reaction,

wherein the diol comprises, based on 100 mole% of the dicarboxylic acid, 0.1 to 5 mole% of 4- (hydroxymethyl) cyclohexylmethyl 4' - (hydroxymethyl) cyclohexanecarboxylate, 0.1 to 12 mole% of 4,4- (oxybis (methylene) bis) cyclohexanemethanol, 0.1 to 15 mole% of 1, 4-cyclohexanedimethanol, 2 to 15 mole% of diethylene glycol, and 53 to 97.7 mole% of ethylene glycol:

[ chemical formula 1]

[ chemical formula 2]

4. The process of claim 3, wherein the esterification reaction is at a reaction temperature of 230 ℃ to 265 ℃ and 1.0kg/cm after injecting the diol in a molar ratio of 1.2 to 3.0 relative to the dicarboxylic acid²To 3.0kg/cm²Is carried out for 100 to 300 minutes under pressure.

5. The process of claim 3, wherein in the polycondensation reaction, additives comprising a polycondensation catalyst, a stabilizer, and a colorant are used.

6. The process of claim 3, wherein the polycondensation reaction is conducted at a reaction temperature of 260 ℃ to 290 ℃ and under reduced pressure of 400mmHg to 0.1 mmHg.

7. A molded product comprising the polyester-based copolymer resin according to claim 1 or 2.

8. The molded product of claim 7, wherein the molded product is a heat shrink film.

9. The molded product of claim 8, wherein the heat shrinkable film has a shrinkage initiation temperature of 60 ℃ or less and a maximum heat shrinkage at 60 ℃ of 4% or more.

10. The molded product of claim 8, wherein the heat shrinkable film has a maximum heat shrinkage at 90 ℃ of 80% or more.