Polyester resin and molded products manufactured from the same polyester resin

Abstract

This invention relates to a polyester resin and molded articles manufactured from the polyester resin. The polyester resin has a specific viscosity controlled within a particular range, and therefore can have excellent processability in the extrusion blow molding process.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention relates to a polyester resin that can exhibit excellent processability when subjected to an extrusion blow molding process, and a molded article prepared using the polyester resin by an extrusion blow molding process.

[0002] [Background Art] Polyester resins are obtained by a polymerization reaction of a dicarboxylic acid component and a diol component. Since they do not contain substances harmful to the human body and are environmentally friendly, they are widely used in the manufacture of films, partition walls, panels, packaging materials, containers, etc. In particular, among polyester resins, polyethylene terephthalate resin is mainly used in the manufacture of small or large containers for containing fruit beverages, soft drinks, carbonated beverages, water, etc.

[0003] These polyester resins have a level of melt viscosity required for a sheet molding process using injection and / or calendar rolls. On the other hand, in order to be employed in an extrusion blow molding process for molding containers, the level of melt viscosity is relatively low.

[0004] In this regard, in U.S. Patent No. 4,217,440, the melt viscosity of a polyester resin is increased by employing a polyfunctional modifier in the polyester resin. In such a case, the molecular weight can be increased by branching, resulting in an increase in melt viscosity, which causes an increase in melt pressure during molding. As a result, when a polyester resin having a polyfunctional modifier is used in an extrusion blow molding process, the melt pressure becomes higher than that of a typical polyester resin, which causes an increase in RPM. Therefore, it is difficult to predict the effect of improving efficiency by shortening the cycle time.

[0005] Therefore, when polyester resin is supplied to an extrusion blow molding process for molded containers, there is a need to develop a technology that can improve processability so that the polyester resin has the required level of melt viscosity even without modification by a polyfunctional modifier.

[0006] [Prior art document] [Patent Document 1] U.S. Patent No. 4,217,440

[0007] [Disclosure of the Invention] [Technical issues] To solve the problems described above in the prior art, the inventors of the present invention conducted various studies. As a result, they found that when the specific viscosity of the polyester resin at a specific temperature is controlled, the processability in the extrusion blow molding process is improved, and high-quality molded products can be obtained. In particular, it was confirmed that the present invention can ensure the processability of polyester resins containing recycled materials.

[0008] Therefore, the object of the present invention is to provide a polyester resin that has excellent processability (moldability) in the extrusion blow molding process.

[0009] Furthermore, another object of the present invention is to provide high-quality molded articles prepared from polyester resin.

[0010] [Solutions to the problem] To achieve the above objective, the present invention provides a polyester resin comprising diol repeating units derived from a diol component and dicarboxylic acid repeating units derived from a dicarboxylic acid component, wherein when analyzed by differential scanning calorimetry (DSC) while raising the temperature to 280°C at a scanning rate of 10°C / min, the melting point (T m ) appears, and the following relational equation 1: [Relationship 1] 10 <X0 / Y2<50 (In relational equation 1, X0 is the angular frequency of 0.5 rad / s, T mThis is the zero shear viscosity of the polyester resin at -15°C, where Y2 is the angular frequency of 500 rad / s, and T m The present invention provides a polyester resin that satisfies the shear viscosity of the polyester resin at +30°C.

[0011] Furthermore, the present invention provides molded articles prepared from this polyester resin.

[0012] Furthermore, the present invention comprises the steps of supplying a polyester resin to an extruder and; and the polyester resin supplied to the extruder having a melting point (T) of the polyester resin. m The process involves barrel processing at a temperature 10-40°C above the melting point (T) of the polyester resin; and processing the processed polyester resin at a temperature 10-40°C above the melting point (T) of the polyester resin. m The present invention provides a method for preparing a molded product, comprising the steps of: preparing a preform by passing it through a die at a temperature below 10-30°C and discharging it; and blow molding the preform.

[0013] [Advantageous effects of the invention] The polyester resin according to the present invention is crystalline, and the ratio of zero shear viscosity to shear viscosity (X0 / Y2), shear viscosity reduction, angular frequency, etc., at a specific temperature are controlled within a specific range. Therefore, when this polyester resin is used in an extrusion blow molding process, it can contribute to providing molded products with excellent quality while exhibiting excellent processability.

[0014] In particular, even when the polyester resin according to the present invention contains repeating units derived from the raw material (e.g., r-EG, r-CHDM, r-ISB, r-DEG, r-NPG, r-BHET, and r-TPA), it possesses the crystallinity and optimal viscosity required for the barrel and die of the extrusion blow molding process, resulting in excellent processability.

[0015] [Best mode for carrying out the invention] The present invention will now be described in detail. The present invention as described herein is not limited to the disclosures shown below, but may be modified in various forms as long as the spirit of the invention is not altered.

[0016] In this specification, the term “comprising” is intended to specify certain characteristics, areas, steps, processes, elements, and / or components. This does not exclude the presence or addition of other characteristics, areas, steps, processes, elements, and / or components unless specifically stated otherwise.

[0017] Throughout this specification, terms such as "1," "2," etc., are used to describe various components. However, components should not be limited by these terms. These terms are used for the purpose of distinguishing one element from another.

[0018] All numbers and expressions relating to quantities of components, reaction conditions, etc., used herein should be understood to be modified by the term "approximately" unless otherwise specified.

[0019] For amorphous polyester resins, it is possible to estimate the degree of processability to be ensured during extrusion blow molding (EBM) by controlling the ratio of zero shear viscosity to shear viscosity. However, in order to perform extrusion blow molding of crystalline polyester resins, the molding (processing) must be carried out at a temperature exceeding the melting point of the crystals. The amount of heat required to melt the crystals is different from the amount of heat required at the temperature at which extrusion blow molding is possible. Therefore, if the ratio of zero shear viscosity to shear viscosity is simply controlled without considering the temperature at which each viscosity is measured, it is difficult to estimate whether processability will be ensured.

[0020] On the other hand, when using crystalline polyester resin in an extrusion blow molding process to prepare molded products, it is possible to prepare molded products with excellent quality (e.g., heat resistance, mechanical strength, appearance, etc.).

[0021] Therefore, in order to ensure the processability during the extrusion blow molding of the crystalline polyester resin, the present invention is characterized in that the ratio of the zero-shear viscosity to the shear viscosity at a specific temperature rather than an arbitrary temperature, and further, the shear thinning property, angular frequency, etc. are controlled. As a result, it is possible to provide a molded product having excellent quality, which will be described in detail below. Polyester resin The polyester resin according to the present invention contains a diol repeating unit derived from a diol component and a dicarboxylic acid repeating unit derived from a dicarboxylic acid component. Since it has crystallinity, a melting point (T m ) appears. Specifically, when the polyester resin according to the present invention is analyzed by differential scanning calorimetry (DSC) while raising the temperature to 280 ° C at a scan rate of 10 ° C / min (when first scanned), one melting point (T m ) may appear.

[0022] The melting point (T m ) of the polyester resin according to the present invention may be, but is not limited to, 210 to 260 ° C. Specifically, the melting point (T m ) may be 215 to 260 ° C, 218 to 258 ° C, 220 to 255 ° C, 221 to 254 ° C, 223 to 253 ° C, 224 to 251 ° C, or 225 to 250 ° C. When the melting point (T m ) is within the above temperature range, the crystallinity of the polyester resin can be increased.

[0023] The differential scanning calorimeter (DSC) may specifically be a modulated differential scanning calorimeter (modulated DSC or MDSC), more specifically a temperature-modulated differential scanning calorimeter (TMDSC).

[0024] The polyester resin according to the present invention satisfies the following relational expression 1. [Relational expression 1] 10 <X0 / Y2 <50 In relational expression 1, X0 is the zero-shear viscosity of the polyester resin at an angular frequency of 0.5 rad / s and T m -15 ° C, and Y2 is the shear viscosity of the polyester resin at an angular frequency of 500 rad / s and Tm This is the shear viscosity of polyester resin at +30°C.

[0025] In relational equation 1, zero shear viscosity can be defined as the viscosity of the polyester resin in the low shear rate region (the viscosity as the shear rate gradually decreases and approaches zero, where a constant viscosity value is maintained), and shear viscosity can be defined as the viscosity of the polyester resin in the high shear rate region.

[0026] As described above, the polyester resin of the present invention has the characteristic that the ratio of zero shear viscosity to shear viscosity (X0 / Y2) measured at a specific temperature satisfies the range of relational expression 1. Specifically, at X0, T m -15℃ is the melting point of polyester resin (T m This temperature is obtained by subtracting 15°C from ), and it is the temperature at which it is possible to determine whether the melt strength of the polyester resin is ensured. That is, T m Measuring the zero-shear viscosity of a polyester resin at a specific temperature of -15°C makes it possible to verify whether the melt strength of the polyester resin required in the extrusion blow molding process (e.g., die extrusion molding process) is ensured, thereby improving processability. Furthermore, at Y2, T m +30℃ is the melting point of polyester resin (T m This temperature is obtained by adding 30°C to ), and this can be the temperature at which the polyester resin is converted to an amorphous state. In other words, in order to accurately measure the shear viscosity of the polyester resin, it is necessary that the polyester resin is non-crystalline. For this purpose, the present invention sets the temperature at which the polyester resin completely melts and becomes amorphous to T m The temperature is specified as +30℃, and the shear viscosity is T m Measurements are taken at a temperature of +30°C.

[0027] When the ratio of zero shear viscosity to shear viscosity (X0 / Y2), measured at a specific temperature, is controlled to the specific range described above in the present invention, a polyester resin with excellent processability in the extrusion blow molding process can be provided. In particular, when the ratio of zero shear viscosity to shear viscosity of the polyester resin is controlled to the specific range described above, small and large molded products can be easily molded by the extrusion blow molding process.

[0028] The ratio (X0 / Y2) may specifically be 10.5 or greater, 11 or greater, 12 or greater, 13 or greater, 14 or greater, 15 or greater, 18 or greater, 20 or greater, 23 or greater, or 25 or greater, and 49.5 or less, 49 or less, 48.5 or less, 48 ​​or less, 47 or less, 45 or less, 43 or less, 40 or less, 38 or less, 37 or less, 36 or less, or 35 or less. For example, the ratio (X0 / Y2) may be 10.5≦X0 / Y2≦49.5, 11≦X0 / Y2≦49, 11.5≦X0 / Y2≦48.5, 12≦X0 / Y2≦48, 13≦X0 / Y2≦47, 14≦X0 / Y2≦45, 16≦X0 / Y2≦43, 18≦X0 / Y2≦42, 19≦X0 / Y2≦40, 21≦X0 / Y2≦38, or 22≦X0 / Y2≦35.

[0029] On the other hand, the zero-shear viscosity of the polyester resin measured at an angular frequency of 0.5 rad / s can be correlated to the viscosity of the polyester resin in the die during the extrusion blow molding process, and the shear viscosity of the polyester resin measured at an angular frequency of 500 rad / s can be correlated to the viscosity of the polyester resin in the barrel during the extrusion blow molding process. In other words, in the present invention, the polyester resin is controlled to have specific viscosities (zero-shear viscosity and shear viscosity) when passing through the barrel and when passing through the die. As a result, processability in the extrusion molding process can be significantly improved.

[0030] Specifically, the polyester resin may have a zero shear viscosity of 10,000-65,000 Pa·s, 15,000-60,000 Pa·s, 16,000-59,000 Pa·s, 17,000-57,000 Pa·s, 18,000-56,000 Pa·s, 19,000-55,000 Pa·s, or 20,000-54,000 Pa·s. Furthermore, the polyester resin may have a shear viscosity of 300-2,000 Pa·s, 350-1,950 Pa·s, 400-1,900 Pa·s, 450-1,850 Pa·s, 500-1,800 Pa·s, 600-1,700 Pa·s, or 700-1,600 Pa·s.

[0031] The polyester resin according to the present invention is represented by the following relational formula 2, T m Shear viscosity reduction of 4-15 at +30℃ (ST Tm+30℃ ) may have. Specifically, T m Shear viscosity reduction at +30°C (ST Tm+30℃ ) may be 4.2-14.8, 4.3-14.5, 4.5-14.3, 4.8-14.1, 4.9-14, 5-13.8, 5-13.6, 5.5-13.5, or 6-13. [Relationship 2] ST Tm+30℃ =Y1 / Y2 In relational equation 2, Y1 is the angular frequency of 0.5 rad / s, T m This is the shear viscosity of the polyester resin at +30°C, where Y2 is the angular frequency of 500 rad / s, and T is the angular frequency of 500 rad / s. m This is the shear viscosity of polyester resin at +30°C.

[0032] Furthermore, the polyester resin according to the present invention is represented by the following relational formula 3, T m Shear viscosity reduction (ST) of 15-30 at -15℃ Tm-15℃ ) may have. Specifically, T m Shear viscosity reduction at -15℃ (ST Tm-15℃) may be 15.3-30, 15.5-30, 16-30, 16.3-30, 16.5-30, 16.8-29.8, 17-29.5, 17.3-29.3, 17.5-29, or 18-28.8. [Relationship 3] ST Tm-15℃ =X1 / X2 In relational equation 3, X1 is the angular frequency of 0.5 rad / s, T m This is the shear viscosity of the polyester resin at -15°C, where X2 is the angular frequency of 500 rad / s, and T is the angular frequency of 500 rad / s. m This is the shear viscosity of polyester resin at -15°C.

[0033] T m +30℃ and T m Shear viscosity reduction value of polyester resin at -15℃ (ST Tm+30℃ and ST Tm-15℃ If each of the above values ​​is within the specified range, a polyester resin with excellent processability in the extrusion blow molding process can be provided.

[0034] The following relation 4 is expressed as T mWhen the tandelta (TD) at -15℃ is 1, the polyester resin according to the present invention may have an angular frequency of 200 rad / s or less. Specifically, the angular frequency may be 5-200 rad / s, 7-200 rad / s, 9-200 rad / s, 10-200 rad / s, 11-200 rad / s, 12-199 rad / s, 13-199 rad / s, 14-199 rad / s, 18-199 rad / s, or 19-199 rad / s. When the angular frequency is within the above range, the melt strength required in the extrusion blow molding process is ensured, and the elasticity of the polyester resin is not impaired; therefore, it is possible to provide molded products with high quality while improving the processability of the polyester resin. In particular, even when the polyester resin is crystalline and contains repeating units derived from recycled raw materials (e.g., r-TPA, r-BHET, r-CHDM, r-EG, r-NPG, r-DEG, and r-ISB), processability in the extrusion blow molding process can be ensured if the angular frequency is controlled to a low value of 200 rad / s or less. [Relationship Equation 4] TD = LM / SM In relational equation 4, LM is T m The loss modulus of elasticity of polyester resin at -15℃ is SM, where T m This is the storage modulus of polyester resin at -15°C.

[0035] According to the present invention, the polyester resin contains repeating diol units derived from a diol component. The diol component is not particularly limited as long as it is a commonly known diol component. Specifically, this includes ethylene glycol, cyclohexanedimethanol, isosorbide, diethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-methylene-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-isopropyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,5-pentanediol, 3-methyl-2,4-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 4-(hydroxymethyl It may contain at least one (specifically, two or more, three or more, or four or more) selected from the group consisting of 4-(4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate (CHDM derivative), 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol (CHDM derivative), bis(2-hydroxyethyl)terephthalate, regenerated ethylene glycol (r-EG), regenerated cyclohexanedimethanol (r-CHDM), regenerated isosorbide (r-ISB), regenerated diethylene glycol (r-DEG), regenerated neopentyl glycol (r-NPG), and regenerated bis(2-hydroxyethyl)terephthalate (r-BHET).

[0036] More specifically, the diol component may include a first diol component comprising at least one selected from the group consisting of ethylene glycol and regenerated ethylene glycol (r-EG); and a second diol component comprising at least one (e.g., two or more or three or more) selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, neopentyl glycol, bis-2-hydroxyethyl terephthalate, regenerated cyclohexanedimethanol (r-CHDM), regenerated isosorbide (r-ISB), regenerated diethylene glycol (r-DEG), regenerated neopentyl glycol (r-NPG), and regenerated bis-2-hydroxyethyl terephthalate (r-BHET).

[0037] The content of the first diol component in the diol component is not particularly limited, but may be 50-99 mol%, 60-99 mol%, 70-99 mol%, 75-98 mol%, or 75-97 mol%, based on the total molar percentage of the diol component. Therefore, the polyester resin may contain repeating units (a) derived from the first diol component. When the amount of the first diol component used is within the above range, a polyester resin with excellent basic physical properties can be manufactured economically.

[0038] The content of the second diol component contained in the diol component is not particularly limited, but may be 5-99 mol%, 5.5-98 mol%, 6-97 mol%, 6-90 mol%, or 6-85 mol%, based on the total molar percentage of the diol component. Therefore, the polyester resin may contain repeating units (b) derived from the second diol component. When the amount of the second diol component used is within the above range, it is possible to prepare a polyester resin with the required level of viscosity in the extrusion blow molding process. As a result, molded articles of excellent quality can be provided.

[0039] In particular, the second diol component may include recycled bis-2-hydroxyethyl terephthalate (r-BHET), which is a recycled raw material. As a result, the polyester resin may contain repeating units (c) derived from the recycled raw material. The amount of recycled bis-2-hydroxyethyl terephthalate (r-BHET) used is not particularly limited, but from the viewpoint of the basic physical properties and processability of the polyester resin, it may be 20-99 mol%, 30-98 mol%, 40-97 mol%, 40-95 mol%, or 40-90 mol%, based on the total molar percentage of the diol component.

[0040] Furthermore, the second diol component may include cyclohexanedimethanol or regenerated cyclohexanedimethanol. As a result, the polyester resin may contain repeating units (e) derived from cyclohexanedimethanol or regenerated cyclohexanedimethanol. The amount of cyclohexanedimethanol or regenerated cyclohexanedimethanol used is not particularly limited, but from the viewpoint of the basic physical properties and processability of the polyester resin, it may be 2-15 mol%, 2-14 mol%, 3-14 mol%, 3-13 mol%, or 3-12 mol%, based on the total mole percent of the diol component.

[0041] Furthermore, the second diol component may include isosorbide or recycled isosorbide. As a result, the polyester resin may contain repeating units (f) derived from isosorbide or recycled isosorbide. The amount of isosorbide or recycled isosorbide used is not particularly limited, but from the viewpoint of the basic physical properties and processability of the polyester resin, it may be 0.1 to 15 mol%, 0.1 to 13 mol%, 0.5 to 10 mol%, 0.5 to 9 mol%, or 0.5 to 8 mol%, based on the total mole percent of the diol component.

[0042] Furthermore, the second diol component may include diethylene glycol or recycled diethylene glycol. As a result, the polyester resin may contain repeating units (g) derived from diethylene glycol or recycled diethylene glycol. The amount of diethylene glycol or recycled diethylene glycol used is not particularly limited, but from the viewpoint of the basic physical properties and processability of the polyester resin, it may be 1 to 15 mol%, 1 to 13 mol%, 1 to 10 mol%, 1.5 to 9 mol%, 1.5 to 8 mol%, 1.5 to 7 mol%, or 2 to 6 mol%, based on the total mole percent of the diol component.

[0043] Furthermore, the second diol component may include neopentyl glycol or recycled neopentyl glycol. As a result, the polyester resin may contain repeating units (h) derived from neopentyl glycol or recycled neopentyl glycol. The amount of neopentyl glycol or recycled neopentyl glycol used is not particularly limited, but from the viewpoint of the basic physical properties and processability of the polyester resin, it may be 0.5 to 15 mol%, 0.5 to 13 mol%, 1 to 10 mol%, 1.5 to 9 mol%, 2 to 8 mol%, 3 to 7 mol%, or 3 to 6 mol%, based on the total mole percent of the diol component.

[0044] According to the present invention, the polyester resin contains repeating dicarboxylic acid units derived from a dicarboxylic acid component. The dicarboxylic acid component is not particularly limited as long as it is a generally known dicarboxylic acid component. Specifically, it may include at least one selected from the group consisting of regenerated terephthalic acid (r-TPA), terephthalic acid, isophthalic acid, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylate, diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 1,3-cyclohexanedicarboxylate, sebacic acid, succinic acid, isodecylsuccinic acid, maleic acid, maleic anhydride, fumaric acid, adipic acid, glutaric acid, and azelaic acid.

[0045] More specifically, the dicarboxylic acid component may include regenerated terephthalic acid (r-TPA), terephthalic acid, isophthalic acid, dimethyl terephthalate, or a combination thereof.

[0046] On the other hand, the recycled ethylene glycol (r-EG), recycled cyclohexanedimethanol (r-CHDM), recycled isosorbide (r-ISB), recycled diethylene glycol (r-DEG), recycled neopentyl glycol (r-NPG), and recycled bis-2-hydroxyethyl terephthalate (r-BHET) used as diol components, and the recycled terephthalic acid (r-TPA) used as a dicarboxylic acid component, may refer to recycled raw materials (monomers) obtained from waste polyester resin or used waste polyester products through commonly known depolymerization processes.

[0047] The polyester resin according to the present invention may further contain repeating units (d) derived from a branching agent having three or more functional groups. The branching agent introduces the repeating units (d) into the side chains of the main chain, or the repeating units (d) form a graft polymerization structure, so that the polyester resin can have a high molecular weight and high crystallinity.

[0048] The content of repeating units (d) contained in the polyester resin is not particularly limited, but may be 0.005 to 15% by weight, specifically 0.005 to 13% by weight, 0.01 to 12% by weight, 0.01 to 10% by weight, or 0.02 to 5% by weight, based on the total weight percentage of diol repeating units.

[0049] The branching agent is not particularly limited, but may specifically be trimellitic acid, trimellitic anhydride, trimethylolpropane, or a combination thereof.

[0050] The polyester resin according to the present invention may have an intrinsic viscosity (IV) of 0.6 to 1.4 dl / g at 35°C. Specifically, the melt intrinsic viscosity (melt IV) of the polyester resin at 35°C may be 0.6 to 1.0 dl / g, 0.62 to 0.97 dl / g, 0.64 to 0.94 dl / g, or 0.65 to 0.90 dl / g. Furthermore, the solid-phase intrinsic viscosity (solid-phase IV) of the polyester resin at 35°C may be 0.8 to 1.4 dl / g, 0.85 to 1.38 dl / g, 0.9 to 1.35 dl / g, or 0.93 to 1.32 dl / g. The melt intrinsic viscosity is the intrinsic viscosity of the polyester resin measured when the polyester resin is obtained after polycondensation (melt polymerization) (before solid-phase polymerization). Solid-phase intrinsic viscosity is the intrinsic viscosity of polyester resin measured when the polyester resin is obtained after polycondensation (melt polymerization) and after solid-phase polymerization.

[0051] The polyester resin according to the present invention may be in the form of chips, pellets, or powder.

[0052] The polyester resin according to the present invention may be a homopolymer or a copolymer. Specifically, the polyester resin may be selected from the group consisting of polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polyester sulfone (PES), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polybutylene adipate-co-terephthalate (PBAT), polypropylene adipate-co-terephthalate (PPAT), polycyclohexanedimethyl terephthalate (PCT), and thermoplastic polyester elastomer (TPEE). Method for preparing polyester resin The polyester resin according to the present invention may be prepared by an esterification reaction or a transesterification reaction followed by a polycondensation reaction, as is generally known. Specifically, the method for preparing the polyester resin according to the present invention may include the steps of supplying a diol component and a dicarboxylic acid component to a reactor (S-1); preparing an oligomer by esterifying the diol component and the dicarboxylic acid component (S-2); and polycondensing the oligomer (S-3), which will be described in detail below. Step (S-1): Supply of raw materials Step (S-1) is the step of supplying the diol component and the dicarboxylic acid component to the reactor. The diol component and the dicarboxylic acid component are the same as described above, so their explanation will be omitted.

[0053] When the diol component and the dicarboxylic acid component are supplied to the reactor, their supply molar ratio (the number of moles of the dicarboxylic acid component relative to the number of moles of the diol component) is not particularly limited, but from the viewpoint of the efficiency of the esterification and polycondensation reactions described later, it may be 1.1 to 2.0, 1.15 to 2.0, 1.15 to 1.9, 1.2 to 1.8, or 1.2 to 1.7.

[0054] A batch reactor or a continuous reactor may be used as the reactor.

[0055] At the same time, at least one additive selected from the group consisting of catalysts, colorants, crystallizers, antioxidants, and branching agents may be supplied to the reactor.

[0056] The catalyst may be sodium and magnesium methylates; acetates, borates, fatty acid salts, or carbonates of Zn, Cd, Mn, Co, Ca, and Ba; and oxides or hydrates of Mg, Pb, Mn, Ti, Sb, Sn, Al, and Ge. For example, the catalyst may be tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, octylene glycol titanate, triethanolamine titanate, acetyl acetonate titanate, acetate ethyl ester titanate, isostearyl titanate, titanium dioxide, germanium dioxide, germanium tetrachloride, germanium ethylene glycoside, germanium acetate, or a combination thereof.

[0057] Organic compounds such as cobalt compounds, anthraquinone compounds, perinone compounds, azo compounds, and methine compounds (e.g., cobalt acetate, cobalt propionate, Clariant's Polysynthren Blue RLS toner, and Clariant's Solvaperm Red BB toner) may be used as colorants.

[0058] As a crystallizing agent, nucleating agents, ultraviolet absorbers, polyolefin resins, polyamide resins, etc., may be used.

[0059] Hindered phenol compounds, phosphate compounds, thioether compounds, etc., may be used as antioxidants.

[0060] As branching agents, trimellitic acid, trimellitic anhydride, trimethylolpropane, or a combination thereof may be used. Step (S-2): Esterification reaction Step (S-2) is a step in which the diol component and the dicarboxylic acid component are esterified to prepare an oligomer. The conditions under which the esterification reaction takes place are not particularly limited.

[0061] Specifically, the temperature at which the esterification reaction takes place may be 210-300°C, 215-290°C, 220-280°C, 230-275°C, 235-270°C, or 240-265°C. Furthermore, the pressure at which the esterification reaction takes place may be 0.05-5 kgf / cm². 2 , 0.1~4 kgf / cm 2 , 0.1~3 kgf / cm² 2 , 0.1~2.5 kgf / cm² 2 , or 0.5~2 kgf / cm² 2 This may also be the case. When the esterification reaction is carried out under the above conditions, the generation of by-reactants is minimized, and oligomers with the desired molecular weight can be obtained in high yield at the same time. Step (S-3): Polycondensation reaction Step (S-3) is a step in which the oligomer undergoes a polycondensation reaction. The conditions under which the polycondensation reaction takes place are not particularly limited.

[0062] Specifically, the temperature at which the polycondensation reaction takes place may be 230-320°C, 235-310°C, 240-300°C, 245-295°C, or 250-290°C. Furthermore, the pressure at which the polycondensation reaction takes place may be lower than atmospheric pressure (e.g., 1 atm) (reduced pressure). When the polycondensation reaction is carried out under the above conditions, a polyester resin (polymer) that is crystalline and ensures excellent processability in the extrusion blow molding process can be efficiently produced.

[0063] On the other hand, if necessary, the method for preparing a polyester resin according to the present invention may further include a step of solid-phase polymerization of the reactants obtained by the polycondensation reaction in step (S-3) in order to control the intrinsic viscosity (IV), molecular weight, etc. of the reactants. The solid-phase polymerization reaction conditions are not particularly limited and may be appropriately set according to the desired intrinsic viscosity, molecular weight, etc. of the polyester resin. Molded products (products) The molded article according to the present invention is prepared from the polyester resin described above. Specifically, the molded article according to the present invention can be obtained by molding the polyester resin using an extrusion blow molding process.

[0064] Since the molded products are prepared from the above-mentioned polyester resin, they may possess excellent quality (e.g., heat resistance, mechanical strength, appearance, etc.). Furthermore, because the molded products are prepared from the above-mentioned polyester resin, the recycling process may also be more efficient if it is carried out after the end of use.

[0065] The molded product is not particularly limited, but may be a small or large container for fruit drinks, soft drinks, carbonated drinks, water, etc. For example, the molded product may be a PET bottle. Method for preparing molded products (products) The method for preparing a molded product according to the present invention comprises the steps of (A) supplying polyester resin to an extruder and (T) the polyester resin supplied to the extruder to the melting point (T) of the polyester resin. m (B) processing the polyester resin in a barrel at a temperature 10-40°C above the melting point (T) of the polyester resin. m The process includes (C) preparing a preform by passing it through a die at a temperature 10-30°C below the limit, and (D) blow molding the preform, which will be described in detail below. Step (A): Supply to the extruder Step (A) is the step of supplying polyester resin to an extruder. The polyester resin may be one in which the ratio of zero shear viscosity to shear viscosity (X0 / Y2), shear viscosity reduction, angular frequency, etc., at a specific temperature are controlled as described above. On the other hand, the extruder to which the polyester resin is supplied may be a conventionally known single-screw extruder or twin-screw extruder. Step (B): Barrel machining Step (B) involves extruding the polyester resin supplied to the extruder, and then extruding the polyester resin at its melting point (T mThis is a step in which the polyester resin is processed in a barrel at a temperature 10 to 40°C above its melting point (T). Specifically, barrel processing of polyester resin involves processing the polyester resin at a temperature 10 to 40°C above its melting point (T). m The process may be carried out at temperatures of 10-35°C, 15-35°C, or 15-30°C or higher. When the processing is carried out within the above temperature range, the processability of the polyester resin is significantly improved, which makes it possible to provide molded products of excellent quality. Step (C): Die molding Step (C) involves processing the polyester resin to the melting point (T) of the polyester resin. m This step involves preparing a preform (e.g., a parison) by passing the polyester resin through a die at a temperature 10-30°C below its melting point (T). Specifically, the discharge of the polyester resin through the die is performed at a temperature 10-30°C below the melting point (T) of the polyester resin. m The discharge may be carried out at temperatures below 10-29°C, 13-28°C, or 15-27°C. When discharge is carried out within the above temperature range, the processability of the polyester resin is significantly improved, which makes it possible to provide molded products of excellent quality. Step (D): Blow molding Step (D) is a step (D) in which the preform is blow-molded. The blow molding of the preform may be carried out by a conventionally known method.

[0066] When molded articles are prepared by steps (A) to (D) described above, the present invention enables the efficient preparation of molded articles of excellent quality. In particular, when the processing temperatures in the barrel and die are controlled within the specific temperature ranges of the present invention, small and large molded articles can be easily molded with excellent processability. The style of the present invention The present invention will be described in more detail below with reference to embodiments. However, these embodiments are provided solely for illustrative purposes, and the present invention is not limited thereto. Example 1 A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 1,257.6 g), regenerated terephthalic acid (r-TPA, 3,287.5 g), isosorbide (ISB, 51.6 g), ethylene glycol (EG, 1,318.5 g), regenerated 1,4-cyclohexanedimethanol (r-CHDM, 356.5 g), diethylene glycol (DEG, 70.0 g), Ge catalyst (1.0 g), Ti catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.005 g), and red toner (0.003 g). Next, the reactor temperature was raised to 265°C, and then a pressure of 2 kgf / cm² was applied at 265°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0067] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 270°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.77 dl / g, the reactants were discharged from the polycondensation reactor.

[0068] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 210°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 210°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.25 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare a polyester resin (copolymer). Example 2 A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated terephthalic acid (r-TPA, 4,231.2 g), ethylene glycol (EG, 2,437.2 g), 1,4-cyclohexanedimethanol (CHDM, 163.1 g), diethylene glycol (DEG, 36.0 g), Ti catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.005 g), red toner (0.005 g), and branching agent (trimellitic anhydride, 0.5 g). Next, the reactor temperature was raised to 255°C, and then the pressure was increased to 1 kgf / cm² at 255°C.2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0069] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.65 dl / g, the reactants were discharged from the polycondensation reactor.

[0070] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 220°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 220°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 0.95 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare a polyester resin (copolymer). Example 3 A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with recycled bis-2-hydroxyethyl terephthalate (r-BHET, 637.7g), terephthalic acid (TPA, 3,751.1g), recycled ethylene glycol (r-EG, 1,515.2g), 1,4-cyclohexanedimethanol (CHDM, 160.7g), recycled neopentyl glycol (r-NPG, 145.1g), diethylene glycol (DEG, 71.0g), Ti catalyst (1.0g), phosphoric acid (1.5g), blue toner (0.01g), and red toner (0.005g). Next, the reactor temperature was raised to 255°C, and then a pressure of 0.5 kgf / cm² was applied at 255°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0071] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.9 dl / g, the reactants were discharged from the polycondensation reactor.

[0072] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 190°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 190°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.2 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare the polyester resin (copolymer). Example 4 In a 10-liter reactor equipped with a column and a condenser that could be cooled with water, terephthalic acid (TPA, 4,051.1 g), isophthalic acid (IPA, 213.2 g), ethylene glycol (EG, 2,643.9 g), recycled diethylene glycol (r-DEG, 108.9 g), Ge catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.025 g), and red toner (0.01 g) were charged. Next, the reactor temperature was raised to 260°C, and then a pressure of 1 kgf / cm² was applied at 260°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0073] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 275°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.78 dl / g, the reactants were discharged from the polycondensation reactor.

[0074] Subsequently, the reactants discharged from the polycondensation reactor were charged into the solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 205°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 205°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.3 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare the polyester resin (copolymer). Example 5 Dimethyl phthalate (DMT, 4,115.4g), regenerated isosorbide (r-ISB, 258.5g), ethylene glycol (EG, 2,537.4g), 1,4-cyclohexanedimethanol (CHDM, 158.7g), diethylene glycol (DEG, 87.6g), Mn catalyst (Mn(II) acetate tetrahydrate, 1.5g), Sb catalyst (Sb2O3, 1.8g), phosphoric acid (1.5g), and cobalt acetate (0.4g) were charged into a 10-liter reactor equipped with a column and a condenser that could be cooled with water. Next, the reactor temperature was raised to 240°C, and then a pressure of 0.1 kgf / cm² was applied at 240°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0075] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 255°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.85 dl / g, the reactants were discharged from the polycondensation reactor.

[0076] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 230°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 230°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.09 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare a polyester resin (copolymer). Example 6 A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 2,562.8g), terephthalic acid (TPA, 2,512.4g), isosorbide (ISB, 26.3g), ethylene glycol (EG, 1,114.9g), 1,4-cyclohexanedimethanol (CHDM, 242.2g), diethylene glycol (DEG, 35.7g), Ge catalyst (1.0g), phosphoric acid (1.5g), cobalt acetate (0.2g), blue toner (0.015g), red toner (0.005g), and branching agent (trimellitic anhydride, 9g). Next, the reactor temperature was raised to 250°C, and then a pressure of 1 kgf / cm² was applied at 250°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0077] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.85 dl / g, the reactants were discharged from the polycondensation reactor.

[0078] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 220°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 220°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.05 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare a polyester resin (copolymer).

[0079] [Comparative Example 1] A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 1,128.4 g), regenerated terephthalic acid (r-TPA, 2,949.8 g), ethylene glycol (EG, 887.5 g), 1,4-cyclohexanedimethanol (CHDM, 1,243.9 g), diethylene glycol (DEG, 157.0 g), Ge catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.005 g), and red toner (0.005 g). Next, the reactor temperature was raised to 273°C, and then a pressure of 0.5 kgf / cm² was applied at 273°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0080] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.8 dl / g, the reactants were discharged from the polycondensation reactor to prepare a polyester resin (copolymer).

[0081] [Comparative Example 2] A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 1,257.7 g), terephthalic acid (TPA, 3,287.8 g), ethylene glycol (EG, 1,170.0 g), 1,4-cyclohexanedimethanol (CHDM, 396.1 g), diethylene glycol (DEG, 70.0 g), Ti catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.005 g), and red toner (0.005 g). Next, the reactor temperature was raised to 263°C, and then a pressure of 0.5 kgf / cm² was applied at 263°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0082] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.7 dl / g, the reactants were discharged from the polycondensation reactor.

[0083] Subsequently, the reactants discharged from the polycondensation reactor were charged into the solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 230°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 230°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare the polyester resin (copolymer).

[0084] [Comparative Example 3] A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 1,316.9 g), terephthalic acid (TPA, 3,356.5 g), isophthalic acid (IPA, 86.1 g), ethylene glycol (EG, 1,585.8 g), diethylene glycol (DEG, 36.6 g), Ti catalyst (1.0 g), phosphoric acid (1.5 g), blue toner (0.01 g), red toner (0.005 g), and branching agent (trimellitic anhydride, 1.5 g). Next, the reactor temperature was raised to 270°C, and then a pressure of 0.5 kgf / cm² was applied at 270°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0085] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.7 dl / g, the reactants were discharged from the polycondensation reactor.

[0086] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 240°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 240°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 0.8 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare the polyester resin (copolymer).

[0087] [Comparative Example 4] A 10-liter reactor equipped with a column and a condenser that could be cooled with water was charged with regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 1,289.5g), terephthalic acid (TPA, 3,286.6g), isophthalic acid (IPA, 84.3g), ethylene glycol (EG, 1,465.3g), regenerated 1,4-cyclohexanedimethanol (r-CHDM, 203.1g), diethylene glycol (DEG, 35.9g), Ti catalyst (1.0g), phosphoric acid (1.5g), blue toner (0.01g), red toner (0.005g), and branching agent (trimellitic anhydride, 0.25g). Next, the reactor temperature was raised to 270°C, and then a pressure of 1 kgf / cm² was applied at 270°C. 2 An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0088] Subsequently, the reactants were transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at 275°C while maintaining the pressure in the polycondensation reactor at a pressure lower than atmospheric pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.7 dl / g, the reactants were discharged from the polycondensation reactor.

[0089] Subsequently, the reactants discharged from the polycondensation reactor were charged into a solid-phase polymerization reactor. The temperature of the solid-phase polymerization reactor was gradually increased to 240°C under a nitrogen atmosphere, and then the solid-phase polymerization reaction was carried out at 240°C. When the intrinsic viscosity (IV) of the reactants in the solid-phase polymerization reactor reached 1.2 dl / g, the reactants were discharged from the solid-phase polymerization reactor to prepare a polyester resin (copolymer).

[0090] [Test Example 1] The polyester resins prepared in Examples 1-6 and Comparative Examples 1-4 were analyzed by differential scanning calorimetry (DSC), and their melting points (T m The presence or absence of ) was determined. The results are shown in Table 1 below. DSC analysis of the polyester resin was performed as follows.

[0091] DSC analyzer: A Mettler Toledo DSC 1 model was used.

[0092] Sample preparation: Approximately 6-10 mg of each polyester resin was collected and placed in an aluminum pot.

[0093] Scanning conditions: The sample was heated from room temperature to 280°C at a rate of 10°C / min, followed by annealing at 280°C for 3 minutes to obtain the DSC curve.

[0094] Melting point (T m Verification: The melting point was defined as the temperature at which an endothermic peak appeared in the obtained DSC curve during the temperature rise procedure.

[0095] [Test Example 2] Anton Paar's Physica MCR 301 instrument was used as a plate-plate rheometer to measure the zero-shear viscosity and shear viscosity of the polyester resins prepared in Examples 1-6 and Comparative Examples 1-4, respectively. Specifically, plates with a diameter of 25 mm were placed parallel to each other at intervals of approximately 1-2 mm. Under a nitrogen atmosphere, T m +30℃ and T m The zero-shear viscosity and shear viscosity of each polyester resin were measured while varying the angular frequency from 0.5 rad / s to 500 rad / s at a temperature of -15°C, and the ratio (X0 / Y2) was calculated according to the following relational equation 1. The results are shown in Table 1 below. [Relationship 1] 10 <X0 / Y2<50 In relational equation 1, X0 is the angular frequency of 0.5 rad / s, T m This is the zero shear viscosity of the polyester resin at -15°C, where Y2 is the angular frequency at 500 rad / s, and T is the angular frequency at 500 rad / s. mThis is the shear viscosity of polyester resin at +30°C.

[0096] [Test Example 3] Anton Paar's Physica MCR 301 instrument was used as a plate-plate rheometer to measure the shear viscosity of the polyester resins prepared in Examples 1-6 and Comparative Examples 1-4. Specifically, plates with a diameter of 25 mm were placed parallel to each other at intervals of approximately 1-2 mm. Under a nitrogen atmosphere, T m +30℃ and T m The shear viscosity of each polyester resin was measured while varying the angular frequency from 0.5 rad / s to 500 rad / s at a temperature of -15°C, and T was calculated according to the following relational equation 2. m Shear viscosity reduction at +30°C (ST Tm+30℃ ) calculate T according to the following relation 3 m Shear viscosity reduction at -15℃ (ST Tm-15℃ The calculation was performed. The results are shown in Table 1 below. The calculation was performed. The results are shown in Table 1 below. [Relationship 2] ST Tm+30℃ =Y1 / Y2 [Relationship 3] ST Tm-15℃ =X1 / X2 In relational equations 2 and 3, Y1 is the angular frequency of 0.5 rad / s, T m This is the shear viscosity of the polyester resin at +30°C, where Y2 is the angular frequency of 500 rad / s, and T is the angular frequency of 500 rad / s. m This is the shear viscosity of the polyester resin at +30°C, where X1 is an angular frequency of 0.5 rad / s, and T is the angular frequency of the polyester resin. m This is the shear viscosity of the polyester resin at -15°C, where X2 is the angular frequency of 500 rad / s, and T is the angular frequency of 500 rad / s. m This is the shear viscosity of polyester resin at -15°C.

[0097] [Test Example 4] Anton Paar's Physica MCR 301 instrument was used as a plate-plate rheometer to measure the loss modulus (T) of the polyester resins prepared in Examples 1-6 and Comparative Examples 1-4, respectively. m (at -15℃) and storage modulus (T m Measurements were taken at -15℃, and using these results, the tandelta value was calculated according to the following relational equation 4. The angular frequency when the tangent delta value is 1 was then measured. The results are shown in Table 1 below. [Relationship Equation 4] TD = LM / SM In relational equation 4, LM is T m The loss modulus of elasticity of polyester resin at -15℃ is SM, where T m This is the storage modulus of polyester resin at -15°C.

[0098] [Table 1]

[0099] Referring to Table 1 above, the polyester resins of Examples 1 to 6 according to the present invention have crystalline properties. m This demonstrates that the ratio of zero shear viscosity to shear viscosity (X0 / Y2), shear viscosity reduction, angular frequency, etc., are controlled within the range of the present invention.

[0100] [Preparation Examples 1-6 and Comparative Preparation Examples 1-4] The polyester resins prepared in Examples 1-6 and Comparative Examples 1-4 were used in an extrusion blow molding process to form 2-liter containers (bottles) with a width (diameter) of 15 cm and a height of 30 cm. In such cases, each polyester resin was supplied to a twin-screw extruder, and the barrel temperature of the twin-screw extruder was set to the melting point (T) of the polyester resin. m The die temperature of the twin-screw extruder is set to a temperature 30°C above the melting point (T) of the polyester resin. m The extrusion blow molding process was carried out by setting the temperature to 15°C below the target temperature, preparing a preform (parison), and then blow molding it.

[0101] [Test Example 5] The containers (bottles) prepared in Preparation Examples 1 to 6 and Comparative Preparation Examples 1 to 4 were evaluated for workability (moldability) and quality according to the following evaluation criteria. The results are shown in Table 2 below. *Evaluation Criteria ◎: The container (bottle) could be molded, and the surface of the container (bottle) was very good.

[0102] 〇: The container (bottle) could be molded, and the surface of the container (bottle) was good.

[0103] △: The deviation of the thickness of the container (bottle) (the percentage of the difference between the thickest thickness (D a ) and the thinnest thickness (D max ) with respect to the average thickness (D min ) was 15% or more, resulting in non-uniform molding and a poor surface of the container (bottle).

[0104] ×: The container (bottle) could not be molded, and the surface of the container (bottle) was poor.

[0105] [Table 2]

[0106] Referring to Table 2 above, it was confirmed that the polyester resins of Examples 1 to 6 according to the present invention had excellent workability (moldability) in the extrusion blow molding process, and that the containers (bottles) of Preparation Examples 1 to 6 prepared therefrom had excellent quality (appearance).

[0107] In contrast, the polyester resin without a melting point (T m ) (Comparative Example 1), or the polyester resins with a ratio of zero-shear viscosity to shear viscosity (X0 / Y2) outside the scope of the present invention (Comparative Examples 2 to 4) could not ensure workability in the extrusion blow molding process. Therefore, it was confirmed that the containers (bottles) of Comparative Examples 1 to 4 prepared therefrom were inferior in quality.

Claims

1. A polyester resin comprising repeating diol units derived from a diol component and repeating dicarboxylic acid units derived from a dicarboxylic acid component, which is analyzed by differential scanning calorimetry (DSC) while increasing the temperature to 280°C at a scanning speed of 10°C / min, has a melting point (T ｍ ) appears, and the following relational equation 1: [Relationship 1] 10 < X ０ / Y ２ <50 (In relational equation 1, X ０ This is an angular frequency of 0.5 rad / s, T ｍ The zero shear viscosity of the polyester resin at -15°C is Y ２ This is an angular frequency of 500 rad / s, T ｍ The shear viscosity of the polyester resin at +30°C satisfies the following conditions: Polyester resin.

2. The following relational equation 2: [Relationship Equation 2] ST Ｔｍ＋３０℃ =Y １ / Y ２ (In relational equation 2, Y １ This is an angular frequency of 0.5 rad / s, T ｍ Y is the shear viscosity of the polyester resin at +30°C. ２ This is an angular frequency of 500 rad / s, T ｍ T is expressed as the shear viscosity of the polyester resin at +30°C. ｍ Shear viscosity reduction of 4 to 15 at +30°C (ST Ｔｍ＋３０℃ ) has The polyester resin according to claim 1.

3. The following relational equation 3: [Relationship Equation 3] ST Ｔｍ－１５℃ =X １ / X ２ (In relational equation 3, X １ This is an angular frequency of 0.5 rad / s, T ｍ X is the shear viscosity of the polyester resin at -15°C. ２ This is an angular frequency of 500 rad / s, T ｍ T is expressed as the shear viscosity of the polyester resin at -15°C. ｍ Shear viscosity reduction of 15 to 30 at -15°C (ST Ｔｍ－１５℃ ) has The polyester resin according to claim 1.

4. The following relational equation 4: [Relational Equation 4] TD = LM / SM (In relational equation 4, LM is T ｍ This is the loss modulus of the polyester resin at -15°C, where SM is T ｍ T is expressed as the storage modulus of the polyester resin at -15°C. ｍ When tandelta (TD) at -15°C is 1, the angular frequency is 200 rad / s or less. The polyester resin according to claim 1.

5. Melting point (T) 210-260°C ｍ The polyester resin according to claim 1, having the following characteristics.

6. The polyester resin according to claim 1, wherein the dicarboxylic acid component comprises at least one selected from the group consisting of regenerated terephthalic acid, terephthalic acid, isophthalic acid, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylate, diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 1,3-cyclohexanedicarboxylate, sebacic acid, succinic acid, isodecyl succinic acid, maleic acid, maleic anhydride, fumaric acid, adipic acid, glutaric acid, and azelaic acid.

7. The aforementioned diol component is ethylene glycol, cyclohexanedimethanol, isosorbide, diethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-methylene-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-isopropyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,5-pentanediol, 3-methyl-2,4-pentanediol, 1,6-hexanediol, 1,2- The polyester resin according to claim 1, comprising at least one selected from the group consisting of cyclohexanediol, 1,4-cyclohexanediol, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol, bis-2-hydroxyethyl terephthalate, recycled ethylene glycol, recycled cyclohexanedimethanol, recycled isosorbide, recycled diethylene glycol, recycled neopentyl glycol, and recycled bis-2-hydroxyethyl terephthalate.

8. The polyester resin according to claim 1, wherein the diol component comprises: a first diol component comprising at least one selected from the group consisting of ethylene glycol and recycled ethylene glycol; and a second diol component comprising at least one selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, neopentyl glycol, bis-2-hydroxyethyl terephthalate, recycled cyclohexanedimethanol, recycled isosorbide, recycled diethylene glycol, recycled neopentyl glycol, and recycled bis-2-hydroxyethyl terephthalate.

9. The polyester resin according to claim 1, further comprising repeating units derived from a branching agent having three or more functional groups.

10. The polyester resin according to claim 9, wherein the content of repeating units derived from the branching agent is 0.005 to 15% by weight, based on the total weight percentage of the diol repeating units.

11. The polyester resin according to claim 1, having an intrinsic viscosity (IV) of 0.6 to 1.4 dl / g.

12. A molded article prepared from the polyester resin according to any one of claims 1 to 11.

13. The molded article according to claim 12, prepared by an extrusion blow molding process.

14. The steps of supplying the polyester resin according to any one of claims 1 to 11 to an extruder; The polyester resin supplied to the extruder is subjected to the melting point (T) of the polyester resin. ｍ The steps include: processing the material in a barrel at a temperature 10 to 40°C above the specified temperature; The processed polyester resin has a melting point (T ｍ The steps include: preparing a preform by passing it through a die at a temperature below 10-30°C and discharging it; The steps include blow molding the aforementioned preform and A method for preparing a molded product, including [a specific component].

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