Polyester resin and method for preparing the same

Abstract

The present invention relates to a polyester resin and a method for preparing the same. The polyester resin comprises repeating diol units derived from a diol component and repeating dicarboxylic acid units derived from a dicarboxylic acid component, and the content ratios of germanium (Ge), zinc (Zn), and phosphorus (P) are controlled within a specific range. The polyester resin according to the present invention can have excellent basic physical properties and color characteristics.

Description

Detailed description of the invention

[0001] [Technical field] The present invention relates to a polyester resin having excellent color characteristics while exhibiting high physical properties such as high heat resistance, chemical resistance, and impact resistance, and to a method for preparing a polyester resin.

[0002] [Background technology] Among polymers, polyester is used as a material in various fields thanks to its excellent mechanical strength, in addition to its heat resistance, chemical resistance, and impact resistance. In particular, polyester films or sheets prepared using polyester resin have good transparency and excellent mechanical strength, and are therefore widely used for containers, boxes, partitions, shelves, panels, packaging materials, building materials, and interior and exterior materials.

[0003] Such polyester resins can be prepared by methods in which the acid and diol components are subjected to direct esterification and / or transesterification in the presence of a polymerization catalyst, followed by their polycondensation. Terephthalic acid (TPA) has typically been used as the acid component, and ethylene glycol (EG) has typically been used as the diol component. However, polyester resins prepared using these components do not have sufficient heat resistance and chemical resistance. In recent years, various aliphatic or aromatic cyclic diol components (e.g., isosorbide (ISB) and cyclohexanedimethanol (CHDM)) have been used in the production of polyester resins.

[0004] However, polyester resins produced using such cyclic diol components exhibit high yellowness (YI) and haze. Therefore, when molded articles are manufactured using such cyclic diol components, there is a problem in that the appearance characteristics of the molded articles (e.g., transparency) are poor. In addition, the polymerization reaction efficiency between the raw material components for preparing polyester resin does not reach a satisfactory level, which limits the ability to increase the productivity of polyester resin.

[0005] Therefore, it is necessary to develop technologies that can increase the productivity of polyester resins and provide molded products with excellent appearance characteristics.

[0006] [Disclosure of the Invention] [Technical challenges] The inventors conducted various studies to solve the problems in the prior art mentioned above. As a result, it was discovered that polyester resins with excellent color properties can be prepared with high efficiency (enhanced productivity) by controlling the content ratios of specific elements contained in the polyester resin within a specific range.

[0007] Accordingly, the object of the present invention is to provide a polyester resin having excellent color properties in addition to its basic properties, and a method for preparing it with high productivity.

[0008] [Means of solving the problem] To achieve the above objective, the present invention provides a polyester resin comprising a diol repeating unit derived from a diol component and a dicarboxylic acid repeating unit derived from a dicarboxylic acid component, wherein the content ratios of germanium (Ge), zinc (Zn), and phosphorus (P) are as follows: 1 and 2 [Relationship 1] 1 ≤ Ge / Zn ≤ 30 [Relationship 2] 1 ≤ (Ge + Zn) / P ≤ 15 We provide a polyester resin that satisfies the requirements.

[0009] In addition, the present invention provides a method for preparing a polyester resin, comprising the steps of: supplying a diol component and a dicarboxylic acid component to a reactor; supplying at least one of a germanium (Ge)-containing catalyst and a zinc (Zn)-containing catalyst and a phosphorus (P)-containing stabilizer to the reactor; subjecting the diol component and the dicarboxylic acid component to an esterification reaction in the presence of the catalyst and the stabilizer to prepare an oligomer; and subjecting the oligomer to a polycondensation reaction, wherein the content ratio among germanium (Ge), zinc (Zn), and phosphorus (P) satisfies the above relationships 1 and 2.

[0010] [Advantageous Effects of the Invention] In the present invention, while controlling the content ratio among specific elements contained in the polyester resin, catalysts and stabilizers of specific components (for example, a germanium (Ge)-containing catalyst, a zinc (Zn)-containing catalyst, and a phosphorus (P)-containing stabilizer) are employed in the reaction process of the polyester resin. As a result, in addition to heat resistance, chemical resistance, and impact resistance, it becomes possible to provide a polyester resin having high mechanical strength and excellent color characteristics (for example, transparency).

[0011] In addition, in the present invention, the polyester resin is prepared such that the content ratio among specific elements contained in the polyester resin is controlled. As a result, in addition to maximizing the productivity of the polyester resin, it becomes possible to provide a polyester resin having a desired intrinsic viscosity (IV).

[0012] [Best Mode for Carrying Out the Invention] The present invention will be described in detail below. The invention in this specification is not limited to the disclosure given below, but can be modified into various forms as long as the gist of the present invention is not changed.

[0013] As used herein, the term "comprising" is intended to specify a particular property, region, step, process, element, and / or component. This does not exclude the presence or addition of any other property, region, step, process, element, and / or component, except when the contrary is specifically stated.

[0014] All numbers and expressions used herein that are related to quantities such as components and reaction conditions should be understood to be modified by the term "about" unless otherwise indicated.

[0015] (Polyester resin) The polyester resin according to the present invention contains a diol repeating unit derived from a diol component, a dicarboxylic acid repeating unit derived from a dicarboxylic acid component, and at least one element selected from the group consisting of germanium (Ge), zinc (Zn), and phosphorus (P), and these are described in detail as follows.

[0016] The diol repeating units contained in the polyester resin according to the present invention are derived from the diol component. The diol component is not particularly limited. Specifically, the 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 It may also contain at least one selected from the group consisting of -2,4-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate (CHDM derivative), 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol (CHDM derivative), bis(2-hydroxyethyl)terephthalate, and regenerated bis(2-hydroxyethyl)terephthalate.

[0017] For example, the diol component may include a first diol component containing ethylene glycol and a second diol component containing at least one (specifically, two or more, three or more, or four or more) selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, bis(2-hydroxyethyl)terephthalate, regenerated bis(2-hydroxyethyl)terephthalate, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, and 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol.

[0018] Here, the second diol compound may include, in addition to regenerated bis(2-hydroxyethyl) terephthalate, at least two or at least three selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, bis(2-hydroxyethyl) terephthalate, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, and 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol.

[0019] If the diol component includes a first diol component and a second diol component, the diol repeating units may include a first diol repeating unit (structural unit) derived from the first diol component and a second diol repeating unit (structural unit) derived from the second diol component. The content of the first diol repeating units (content of the first diol repeating units contained in the polyester resin) is not particularly limited, but may be 5 to 95 mol%, 10 to 90 mol%, 10 to 85 mol%, 15 to 85 mol%, or 20 to 70 mol% based on the total number of moles of diol repeating units. In addition, the content of the second diol repeating units (content of the second diol repeating units contained in the polyester resin) is not particularly limited, but may be 5 to 95 mol%, 10 to 90 mol%, 10 to 85 mol%, 15 to 85 mol%, or 20 to 70 mol% based on the total number of moles of diol repeating units. Since the content of the first diol repeating unit and the content of the second diol repeating unit are within the above range, a polyester resin with excellent heat resistance, chemical resistance, color properties, and productivity can be provided.

[0020] In addition, if the second diol component contains at least one comonomer selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, bis(2-hydroxyethyl)terephthalate, regenerated bis(2-hydroxyethyl)terephthalate, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, and 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol, the diol repeating units may also contain repeating units (structural units) derived from the comonomer. For example, the content of repeating units derived from cyclohexanedimethanol (the content of repeating units derived from cyclohexanedimethanol contained in the polyester resin) is not particularly limited, but may be 1 to 10 mol%, 2 to 9 mol%, 3 to 8 mol%, or 3 to 7 mol% based on the total number of moles of diol repeating units. The content of repeating units derived from isosorbide (the content of repeating units derived from isosorbide contained in the polyester resin) is not particularly limited, but may be 1 to 70 mol%, 2 to 65 mol%, 3 to 60 mol%, or 4 to 60 mol% based on the total number of moles of diol repeating units. The content of repeating units derived from diethylene glycol (the content of repeating units derived from diethylene glycol contained in the polyester resin) is not particularly limited, but may be 1 to 10 mol%, 1 to 9 mol%, 1 to 8 mol%, or 1 to 7 mol% based on the total number of moles of diol repeating units. The content of repeating units derived from recycled bis(2-hydroxyethyl) terephthalate (the content of repeating units derived from recycled bis(2-hydroxyethyl) terephthalate contained in the polyester resin) is not particularly limited, but may be 1 to 100 mol%, 2 to 100 mol%, 3 to 100 mol%, 4 to 100 mol%, 4 to 95 mol%, or 4 to 90 mol% based on the total number of moles of diol repeating units.

[0021] The dicarboxylic acid repeating units contained in the polyester resin according to the present invention are derived from a dicarboxylic acid component. The dicarboxylic acid component is not particularly limited. Specifically, the dicarboxylic acid component may include at least one selected from the group consisting of isophthalic acid, terephthalic acid, dimethyl isophthalate, phthalic acid, dimethyl phthalate, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylate, diphenyl dicarboxylic 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.

[0022] For example, the dicarboxylic acid component may include at least one selected from the group consisting of isophthalic acid, terephthalic acid, dimethyl phthalate, and dimethyl isophthalate. Preferably, the dicarboxylic acid component may include isophthalic acid, terephthalic acid, or a combination thereof.

[0023] If the dicarboxylic acid component includes isophthalic acid and / or terephthalic acid, the dicarboxylic acid repeating units may include isophthalic acid repeating units (structural units) derived from isophthalic acid, terephthalic acid repeating units (structural units) derived from terephthalic acid, or a combination thereof. The content of isophthalic acid repeating units (content of isophthalic acid repeating units contained in the polyester resin) is not particularly limited, but may be 1 to 10 mol%, 2 to 10 mol%, 3 to 10 mol%, or 4 to 10 mol% based on the total number of moles of dicarboxylic acid repeating units. The content of terephthalic acid repeating units (content of terephthalic acid repeating units contained in the polyester resin) is not particularly limited, but may be 1 to 100 mol%, 2 to 100 mol%, 3 to 100 mol%, 4 to 100 mol%, 90 to 96 mol%, 90 to 97 mol%, 90 to 98 mol%, or 90 to 99 mol% based on the total number of moles of dicarboxylic acid repeating units. Since the content of isophthalic acid repeating units and terephthalic acid repeating units are within the above ranges, a polyester resin with excellent heat resistance, chemical resistance, impact resistance, and productivity can be provided.

[0024] The elements contained in the polyester resin according to the present invention may include at least one selected from the group consisting of germanium (Ge), zinc (Zn), and phosphorus (P). Here, the above elements, germanium (Ge), zinc (Zn), and phosphorus (P) can satisfy the content ratio (weight ratio) according to the following relationships 1 and 2. [Relationship 1] 1 ≤ Ge / Zn ≤ 30 [Relationship 2] 1 ≤ (Ge + Zn) / P ≤ 15

[0025] Specifically, when the polyester resin contains germanium (Ge) and zinc (Zn), the Ge / Zn ratio, which is the ratio of their content, may be 1 to 30. More specifically, the Ge / Zn ratio may be 1.1 to 29, 1.2 to 29, 1.3 to 28, 1.4 to 28, 1.5 to 27, 1.6 to 27, 1.8 to 26, 2 to 24, 2.5 to 22, 3 to 20, 5 to 19, 8 to 17, or 9 to 16. Because the Ge / Zn ratio is within the above range, it is possible to provide a polyester resin having remarkably excellent color properties and a desired intrinsic viscosity (IV).

[0026] On the other hand, when a polyester resin contains germanium (Ge), zinc (Zn), and phosphorus (P), the ratio of their content, (Ge+Zn) / P, may be between 1 and 15. Specifically, the (Ge+Zn) / P ratio may be 1.1-14.8, 1.2-14.6, 1.3-14.4, 1.4-14.2, 1.5-14, 1.6-13.8, 1.8-13.4, 2-13.2, 2.5-13, 3-12.5, 3.3-12, 3.5-11, 3.8-10, or 4-9.5. Because the (Ge+Zn) / P ratio is within the above range, a polyester resin with remarkably excellent heat resistance, chemical resistance, and color properties can be provided with high efficiency. In particular, when the (Ge+Zn) / P ratio is within the above range, the productivity of the polyester resin can be maximized.

[0027] The germanium (Ge) element contained in the polyester resin according to the present invention may be derived from a germanium (Ge)-containing catalyst. The germanium (Ge)-containing catalyst is not particularly limited as long as it is a generally known catalyst. Specifically, the germanium (Ge)-containing catalyst may include at least one selected from the group consisting of a salt of an aliphatic carboxylic acid containing germanium (Ge), a salt of an aromatic carboxylic acid containing germanium (Ge), a salt of a halogenated carboxylic acid containing germanium (Ge), a salt of a hydroxycarbonate containing germanium (Ge), a salt of an inorganic substance containing germanium (Ge), an organic sulfonate containing germanium (Ge), an organic sulfate containing germanium (Ge), an alkoxide containing germanium (Ge), an acetylacetonate containing germanium (Ge), an oxide containing germanium (Ge), a metal containing germanium (Ge), and a hydroxide containing germanium (Ge).

[0028] The aliphatic carboxylic acid salt containing germanium (Ge) is not particularly limited, but may specifically be a formate, acetate (e.g., germanium acetate), propionate, butyrate, oxalate, acrylate, or methacrylate containing germanium (Ge).

[0029] The aromatic carboxylic acid salt containing germanium (Ge) is not particularly limited, but may specifically be a benzoate containing germanium (Ge).

[0030] The germanium (Ge)-containing halogenated carboxylic acid salt is not particularly limited, but may specifically be a germanium (Ge)-containing trichloroacetate or trifluoroacetate.

[0031] The hydroxycarbonate salt containing germanium (Ge) is not particularly limited, but may specifically be a lactate, citrate, or oxalate containing germanium (Ge).

[0032] The inorganic salts containing germanium (Ge) are not particularly limited, but may specifically include germanium (Ge)-containing carbonates, sulfates, nitrates, phosphates, phosphonates, phosphines, bisulfites, bicarbonates, hydrogen phosphates, sulfites, thiosulfates, hydrochlorides, hydrobromides, chlorides (e.g., germanium tetrachloride), chlorates, bromides, or bolomates.

[0033] The organic sulfonate containing germanium (Ge) is not particularly limited, but may specifically be a 1-propane sulfonate, 1-pentane sulfonate, or naphthalene sulfonate containing germanium (Ge).

[0034] The organic sulfate containing germanium (Ge) is not particularly limited, but specifically, it may be a lauryl sulfate containing germanium (Ge).

[0035] The germanium (Ge)-containing alkoxide is not particularly limited, but may specifically be a germanium (Ge)-containing methoxide, ethoxide, propoxide, isopropoxide, or butoxide.

[0036] The oxide containing germanium (Ge) is not particularly limited, but specifically, it may be germanium dioxide (GeO2).

[0037] The germanium (Ge) content derived from such germanium (Ge)-containing catalysts is not particularly limited, but may be 10-500 ppm, 30-500 ppm, 40-490 ppm, 80-490 ppm, 105-480 ppm, 120-480 ppm, 130-470 ppm, 140-460 ppm, 150-450 ppm, 155-430 ppm, or 155-420 ppm based on the total weight of the polyester resin. Since the germanium (Ge) content is within the above range, relationships 1 and 2 above are satisfied, thereby enabling the preparation of polyester resins with excellent color properties with high efficiency.

[0038] The zinc (Zn) element contained in the polyester resin according to the present invention may be derived from a zinc (Zn)-containing catalyst. The zinc (Zn)-containing catalyst is not particularly limited as long as it is a generally known catalyst. Specifically, the zinc (Zn)-containing catalyst may include at least one selected from the group consisting of zinc acetate, zinc acetate dihydrate, zinc chloride, zinc sulfate, zinc sulfide, zinc carbonate, zinc citrate, and zinc gluconate.

[0039] The zinc (Zn) content derived from such a zinc (Zn)-containing catalyst is not particularly limited, but may be 5-200 ppm, 6-200 ppm, 7-190 ppm, 8-190 ppm, 9-180 ppm, 9-170 ppm, 10-170 ppm, 10-160 ppm, 10-155 ppm, 11-150 ppm, or 16-150 ppm based on the total weight of the polyester resin. Since the zinc (Zn) content is within the above range, relationships 1 and 2 above are satisfied, thereby enabling the preparation of polyester resins with excellent color properties with high efficiency.

[0040] The phosphorus (P) element contained in the polyester resin according to the present invention may be derived from a phosphorus (P)-containing stabilizer. The phosphorus (P)-containing stabilizer is not particularly limited as long as it is a generally known stabilizer. Specifically, the phosphorus (P)-containing stabilizer may include at least one selected from the group consisting of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, and triethyl phosphonoacetate.

[0041] The phosphorus (P) content derived from such phosphorus (P)-containing stabilizers is not particularly limited, but may be 1-250 ppm, 1-245 ppm, 2-245 ppm, 2-240 ppm, 3-235 ppm, 3-230 ppm, 4-225 ppm, 4-220 ppm, 10-215 ppm, 20-210 ppm, or 25-205 ppm based on the total weight of the polyester resin. Since the phosphorus (P) content is within the above range, relationships 1 and 2 above are satisfied, thereby enabling the preparation of polyester resins with excellent color properties with high efficiency.

[0042] On the one hand, the polyester resin according to the present invention may further contain, or may not contain, elements derived from additives used in the preparation of the polyester resin (for example, titanium (Ti), silicon (Si), antimony (Sb), tin (Sn), or aluminum (Al)), in addition to germanium (Ge), zinc (Zn), and phosphorus (P).

[0043] As described above, in the present invention, among the various elements that will be contained in the polyester resin, germanium (Ge), zinc (Zn), and phosphorus (P), which are specific elements, are contained in the polyester resin and satisfy relationships 1 and 2 above. As a result, it is possible to provide a polyester resin that has excellent basic physical properties such as heat resistance, chemical resistance, and impact resistance, in addition to significantly improved color characteristics. Furthermore, in the present invention, the polyester resin is prepared such that germanium (Ge), zinc (Zn), and phosphorus (P) satisfy relationships 1 and 2 above. As a result, it is possible to provide a polyester resin that has a desired intrinsic viscosity (IV), in addition to the maximized productivity of the polyester resin.

[0044] Specifically, the polyester resin according to the present invention may have a col-b value of -4 to +4 in pellet form, exhibiting excellent color properties (e.g., transparency). More specifically, the col-b value in pellet form may be -4 to +3.5, -3.8 to +3, -3.6 to +2.6, -3.3 to +2, or -3 to +1.5. Col-b is a color coordinate established by the International Commission on Illumination (CIE), in which color is represented by the "complementary color from yellow to blue". Col-b may be measured using UltraScan PRO (manufacturer: Hunterlab).

[0045] In addition, the polyester resin according to the present invention may have an intrinsic viscosity (IV) of 0.6 to 1.3 dl / g at 35°C, specifically 0.6 to 1.28 dl / g, 0.6 to 1.25 dl / g, 0.6 to 1.23 dl / g, 0.6 to 1.2 dl / g, or 0.6 to 1.15 dl / g. Since the intrinsic viscosity is within the above range, the processability of the polyester resin can be guaranteed.

[0046] 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).

[0047] The polyester resin according to the present invention may be in the form of chips, pellets, or powder.

[0048] (Method for preparing polyester resin) The present invention provides a method for preparing the polyester resin described above. Specifically, the method for preparing the polyester resin includes the steps of supplying a diol component and a dicarboxylic acid component to a reactor (S-1), supplying at least one of a germanium (Ge)-containing catalyst and a zinc (Zn)-containing catalyst and a phosphorus (P)-containing stabilizer to the reactor (S-2), subjecting the diol component and the dicarboxylic acid component to an esterification reaction in the presence of the catalyst and stabilizer to prepare an oligomer (S-3), and subjecting the oligomer to a polycondensation reaction (S-4), which are described in detail below.

[0049] 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. Since the diol component and the dicarboxylic acid component are the same as described above, their explanation will be omitted.

[0050] When the diol component and the dicarboxylic acid component are supplied to the reactor, the molar ratio of their supply (moles of diol component / moles of dicarboxylic acid 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, 1.1 to 1.9, 1.1 to 1.8, or 1.1 to 1.7.

[0051] A batch reactor or a continuous reactor may be used as the reactor.

[0052] Step (S-2): Supply of catalyst and stabilizer Step (S-2) is the step of supplying at least one of the germanium (Ge)-containing catalyst and the zinc (Zn)-containing catalyst, as well as a phosphorus (P)-containing stabilizer, to the reactor. The germanium (Ge)-containing catalyst, the zinc (Zn)-containing catalyst, and the phosphorus (P)-containing stabilizer are the same as described above, so their descriptions are omitted.

[0053] On the other hand, in addition to the germanium (Ge)-containing catalyst and / or zinc (Zn)-containing catalyst and phosphorus (P)-containing stabilizer, a generally known additive comprising at least one selected from the group consisting of catalysts, colorants, crystallizers, antioxidants, and branching agents may be further supplied to the reactor.

[0054] The catalyst may be sodium and magnesium methylates; acetates, borates, fatty acid salts, or carbonates of Cd, Mn, Co, Ca, and Ba; and oxides or hydrates of Mg, Pb, Mn, Ti, Sb, Sn, and Al. Examples of catalysts include tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, lactate titanate, octylene glycol titanate, triethanolamine titanate, acetyl acetonate titanate, ethyl acetoacetate titanate, isostearyl titanate, titanium dioxide, and combinations thereof.

[0055] 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.

[0056] As a crystallizing agent, crystal nucleating agents, ultraviolet absorbers, polyolefin resins, or polyamide resins may be used.

[0057] As antioxidants, hindered phenol compounds, phosphite compounds, or thioether compounds may be used.

[0058] As a branching agent, trimellitic anhydride, trimethylolpropane, or trimellitic anhydride may be used.

[0059] Step (S-2) may be performed after step (S-1) or simultaneously with step (S-1). In addition, germanium (Ge)-containing catalysts, zinc (Zn)-containing catalysts, phosphorus (P)-containing stabilizers, and additives may be supplied when steps (S-3) and / or (S-4), which are described below, are performed.

[0060] Step (S-3): Esterification reaction Step (S-3) is a step in which the diol component and the dicarboxylic acid component are subjected to an esterification reaction in the presence of at least one of a germanium (Ge)-containing catalyst and a zinc (Zn)-containing catalyst, as well as a phosphorus (P)-containing stabilizer, in order to prepare an oligomer.

[0061] The conditions under which the esterification reaction takes place are not particularly limited. Specifically, the temperature at which the esterification reaction takes place may be 200-300°C, more specifically, 220-300°C, 230-295°C, 240-290°C, 250-285°C, or 260-280°C. In addition, the pressure at which the esterification reaction takes place may be 0.1-5 kgf / cm². 2 Specifically, 0.2 to 4.5 kgf / cm² 2 , 0.3~4 kgf / cm 2 , 0.4~3.5 kgf / cm 2 , or 0.5~3 kgf / cm² 2 The esterification reaction may be carried out for 2 to 10 hours, specifically 3 to 9 hours, 3.5 to 8.5 hours, 3.5 to 8 hours, or 4 to 7.5 hours. Because the esterification reaction is carried out under the above conditions, the production of by-reactants is minimized, while oligomers with the desired molecular weight can be obtained in high yield.

[0062] Step (S-4): Polycondensation reaction Step (S-4) is a step in which the oligomer is subjected to a polycondensation reaction.

[0063] The conditions under which the polycondensation reaction takes place are not particularly limited. Specifically, the temperature at which the polycondensation reaction takes place may be 220-300°C, more specifically 230-300°C, 240-295°C, 250-290°C, or 260-285°C. In addition, the conditions under which the polycondensation reaction takes place may be lower than the standard pressure (e.g., 1 atm) (reduced pressure). The duration of the polycondensation reaction may be 1-24 hours, specifically 1-20 hours, 2-15 hours, 3-10 hours, or 3.5-8 hours. Because the polycondensation reaction takes place under the above conditions, polyester resins (polymers) with desired intrinsic viscosity and color properties can be efficiently produced, while by-products are smoothly discharged.

[0064] The polyester resin of the present invention, prepared through steps (S-1) to (S-4), has germanium (Ge), zinc (Zn), and phosphorus (P) content ratios that satisfy the following relationships 1 and 2. The Ge / Zn ratio in relationship 1 and the (Ge+Zn) / P ratio in relationship 2 are the same as described above, so their explanation is omitted. [Relationship 1] 1 ≤ Ge / Zn ≤ 30 [Relationship 2] 1 ≤ (Ge + Zn) / P ≤ 15

[0065] In the method for preparing a polyester resin according to the present invention, a polyester resin satisfying the above relationships 1 and 2 is prepared. Therefore, a polyester resin with excellent color properties can be provided with high productivity.

[0066] Specifically, when a polyester resin is prepared by the method for preparing a polyester resin according to the present invention, productivity is increased, and the preparation method has a process consumption rate of less than 65% (T) according to the following relationship 3. c ) can have. More specifically, process consumption rate (T c) may be 64% or less, 62% or less, 61% or less, 60% or less, 59% or less, 57% or less, 55% or less, 53% or less, 51% or less, 48% or less, or 45% or less (for example, less than 5 to 65%, 10 to 63%, 15 to 60%, 20 to 58%, 25 to 53%, 30 to 50%, or 35 to 48%). [Relationship 3] T c (%) = (T c2 / T c1 + T c2 ) × 100

[0067] In Relationship 3, T c1 is the time taken for the esterification reaction during the method for preparing the polyester resin (the time taken in step (S - 3)), and T c2 is the time taken for the polycondensation reaction during the method for preparing the polyester resin (the time taken in step (S - 4)).

[0068] In addition, when a polyester resin is prepared by the method for preparing a polyester resin according to the present invention, the productivity is enhanced, and thereby the preparation method can have one or more productivity improvements (PI) according to the following Relationship 4. Specifically, the productivity improvement (PI) may be 1.1 or more, 1.13 or more, 1.15 or more, 1.18 or more, 1.2 or more, 1.23 or more, 1.25 or more, 1.28 or more, 1.3 or more, 1.33 or more, 1.36 or more, 1.4 or more, 1.45 or more, 1.5 or more, 1.65 or more, 1.75 or more, 1.9 or more, or 2 or more (for example, 1 to 2.5, 1.11 to 2.3, 1.15 to 2.1, 1.2 to 2, 1.25 to 1.95, or 1.35 to 1.93). [Relationship 4] PI = IV × (T c1 + T c2 / T c2 )

[0069] In Relationship 4, IV is the intrinsic viscosity of the polyester resin, and T c1 is the time taken for the esterification reaction during the method for preparing the polyester resin, and T c2This is the time required for the polycondensation reaction in the method for preparing the polyester resin.

[0070] On the other hand, steps (S-1) to (S-4) may be carried out sequentially. By-products formed in step (S-3) and / or step (S-4) (e.g., side reaction products, unreacted diol components, and unreacted dicarboxylic acid components) may be recovered and purified. The purified material obtained by the above purification process (e.g., ethylene glycol) may then be reused as a reaction raw material.

[0071] [Mode of the invention] The present invention will be described in more detail below with reference to embodiments. However, these examples are provided for illustrative purposes only, and the present invention is not limited to these examples.

[0072] [Example 1] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 531.2 kg / hour), terephthalic acid (TPA, 1,388.7 kg / hour), ethylene glycol (EG, 415.0 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 150.6 kg / hour), isosorbide (ISB, 61.1 kg / hour), and diethylene glycol (DEG, 22.2 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0073] Next, Zn catalyst (zinc acetate, 0.09 kg / hour), Ge catalyst (GeO2, 1.3 kg / hour), Ti catalyst (0.19 kg / hour), phosphoric acid (0.021 kg / hour), blue toner (0.008 kg / hour), and red toner (0.002 kg / hour) were continuously supplied to the continuous reactor.

[0074] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 260°C, and then 0.5 kgf / cm² was applied at 260°C. 2Under pressure, the esterification reaction (ES) was carried out for 7 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0075] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 265°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.60 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 7 hours.

[0076] Next, the reactants discharged from the polycondensation reactor were introduced into the solid-phase polymerization reactor. Under a nitrogen atmosphere, the temperature of the solid-phase polymerization reactor was gradually raised to 200°C, and then the solid-phase polymerization reaction was carried out at 200°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 a polyester resin (copolymer) in pellet form.

[0077] [Example 2] Terephthalic acid (TPA, 1,578.9 kg / hour), ethylene glycol (EG, 357.7 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 547.8 kg / hour), isosorbide (ISB, 185.2 kg / hour), and diethylene glycol (DEG, 10.1 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0078] Next, Zn catalyst (zinc acetate, 0.06 kg / hour), Ge catalyst (GeO2, 5.3 kg / hour), Ti catalyst (0.19 kg / hour), phosphoric acid (0.167 kg / hour), blue toner (0.005 kg / hour), and red toner (0.001 kg / hour) were continuously supplied to the continuous reactor.

[0079] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 255°C, and then the pressure was increased to 2 kgf / cm² at 255°C. 2Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0080] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 285°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.7 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 7 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0081] [Example 3] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 112.0 kg / hour), terephthalic acid (TPA, 1,390.9 kg / hour), ethylene glycol (EG, 47.4 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 889.1 kg / hour), isosorbide (ISB, 377.7 kg / hour), and diethylene glycol (DEG, 9.3 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0082] Next, Zn catalyst (zinc acetate, 0.88 kg / hour), Ge catalyst (GeO2, 13.3 kg / hour), phosphoric acid (0.938 kg / hour), blue toner (0.006 kg / hour), and red toner (0.002 kg / hour) were continuously supplied to the continuous reactor.

[0083] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 265°C, and then the pressure was increased to 1 kgf / cm² at 265°C. 2 Under pressure, the esterification reaction (ES) was carried out for 4 hours to obtain the oligomer. During this process, the esterification reaction was carried out while discharging by-products such as ethylene glycol and water to the outside of the continuous reactor.

[0084] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 270°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.75 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 6 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0085] [Example 4] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 982.8 kg / hour), terephthalic acid (TPA, 481.7 kg / hour), isophthalic acid (IPA, 642.3 kg / hour), ethylene glycol (EG, 28.0 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 487.5 kg / hour), isosorbide (ISB, 188.3 kg / hour), and diethylene glycol (DEG, 20.5 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0086] Next, Zn catalyst (zinc acetate, 0.18 kg / hour), Ge catalyst (GeO2, 9.3 kg / hour), Ti catalyst (0.19 kg / hour), phosphoric acid (1.042 kg / hour), and blue toner (0.01 kg / hour) were continuously supplied to the continuous reactor.

[0087] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 268°C, and then 3 kgf / cm² was applied at 268°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0088] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 280°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.85 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 4 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0089] [Example 5] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 962.4 kg / hour), terephthalic acid (TPA, 943.4 kg / hour), ethylene glycol (EG, 13.7 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 818.4 kg / hour), isosorbide (ISB, 645.4 kg / hour), and diethylene glycol (DEG, 10.0 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0090] Next, Zn catalyst (zinc acetate, 0.06 kg / hour), Ge catalyst (GeO2, 8.8 kg / hour), phosphoric acid (0.313 kg / hour), blue toner (0.01 kg / hour), and red toner (0.004 kg / hour) were continuously supplied to the continuous reactor.

[0091] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 270°C, and then 3 kgf / cm² was applied at 270°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0092] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 280°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.65 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 4 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0093] [Example 6] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 553.7 kg / hour), terephthalic acid (TPA, 1,447.5 kg / hour), ethylene glycol (EG, 4.5 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 627.8 kg / hour), isosorbide (ISB, 1,167.0 kg / hour), and diethylene glycol (DEG, 11.6 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0094] Next, Zn catalyst (zinc acetate, 0.58 kg / hour), Ge catalyst (GeO2, 5.3 kg / hour), phosphoric acid (0.146 kg / hour), blue toner (0.01 kg / hour), and red toner (0.004 kg / hour) were continuously supplied to the continuous reactor.

[0095] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 275°C, and then 3 kgf / cm² was applied at 275°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0096] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 277°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.6 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 4 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0097] [Comparative Example 1] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 159.4 kg / hour), terephthalic acid (TPA, 937.4 kg / hour), ethylene glycol (EG, 451.3 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 90.4 kg / hour), and isosorbide (ISB, 36.6 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0098] Next, Ge catalyst (GeO2, 0.8 kg / hour), Ti catalyst (0.11 kg / hour), phosphoric acid (0.125 kg / hour), blue toner (0.003 kg / hour), and red toner (0.001 kg / hour) were continuously supplied to the continuous reactor.

[0099] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 255°C, and then the pressure was increased to 2 kgf / cm² at 255°C. 2 Under pressure, the esterification reaction (ES) was carried out for 6 hours to obtain the oligomer. During this process, the esterification reaction was carried out while discharging by-products such as ethylene glycol and water to the outside of the continuous reactor.

[0100] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 265°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.7 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 11 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0101] [Comparative Example 2] Terephthalic acid (TPA, 878.5 kg / hour), ethylene glycol (EG, 146.6 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 533.4 kg / hour), isosorbide (ISB, 226.6 kg / hour), and diethylene glycol (DEG, 5.6 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0102] Next, Zn catalyst (zinc acetate, 0.11 kg / hour), Ge catalyst (GeO2, 0.8 kg / hour), blue toner (0.003 kg / hour), and red toner (0.001 kg / hour) were continuously supplied to the continuous reactor.

[0103] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 265°C, and then the pressure was increased to 1 kgf / cm² at 265°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0104] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 275°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.75 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 5 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0105] [Comparative Example 3] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 577.4 kg / hour), terephthalic acid (TPA, 566.1 kg / hour), ethylene glycol (EG, 8.2 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 491.0 kg / hour), isosorbide (ISB, 387.2 kg / hour), and diethylene glycol (DEG, 6.0 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0106] Next, Zn catalyst (zinc acetate, 0.7 kg / hour), Ge catalyst (GeO2, 1.6 kg / hour), phosphoric acid (0.025 kg / hour), blue toner (0.004 kg / hour), and red toner (0.001 kg / hour) were continuously supplied to the continuous reactor.

[0107] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 275°C, and then the pressure was increased to 1 kgf / cm² at 275°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0108] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 280°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.5 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 10 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0109] [Comparative Example 4] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 144.4 kg / hour), terephthalic acid (TPA, 849.1 kg / hour), ethylene glycol (EG, 219.6 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 491.0 kg / hour), isosorbide (ISB, 387.2 kg / hour), and diethylene glycol (DEG, 6.0 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0110] Next, Zn catalyst (zinc acetate, 0.18 kg / hour), Ge catalyst (GeO2, 1.6 kg / hour), phosphoric acid (0.438 kg / hour), blue toner (0.006 kg / hour), and red toner (0.003 kg / hour) were continuously supplied to the continuous reactor.

[0111] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 275°C, and then the pressure was increased to 1 kgf / cm² at 275°C. 2 Under pressure, the esterification reaction (ES) was carried out for 4 hours to obtain the oligomer. During this process, the esterification reaction was carried out while discharging by-products such as ethylene glycol and water to the outside of the continuous reactor.

[0112] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 280°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.5 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 12 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0113] [Comparative Example 5] Recycled bis(2-hydroxyethyl) terephthalate (r-BHET, 166.1 kg / hour), terephthalic acid (TPA, 977.0 kg / hour), ethylene glycol (EG, 225.7 kg / hour), 1,4-cyclohexanedimethanol (CHDM, 376.7 kg / hour), isosorbide (ISB, 700.2 kg / hour), and diethylene glycol (DEG, 6.9 kg / hour) were continuously supplied to a continuous reactor equipped with a column and a condenser that could be cooled by water.

[0114] Next, Zn catalyst (zinc acetate, 0.04 kg / hour), Ge catalyst (GeO2, 6.4 kg / hour), phosphoric acid (0.088 kg / hour), blue toner (0.006 kg / hour), and red toner (0.003 kg / hour) were continuously supplied to the continuous reactor.

[0115] Next, under a nitrogen atmosphere, the temperature of the continuous reactor was gradually raised to 275°C, and then the pressure was increased to 1 kgf / cm² at 275°C. 2 Under pressure, the esterification reaction (ES) was carried out for 5 hours to obtain the oligomer. During this esterification reaction, by-products such as ethylene glycol and water were discharged to the outside of the continuous reactor.

[0116] Next, the oligomer was transferred to a polycondensation reactor, and the polycondensation reaction (PA) was carried out at a temperature of 280°C while maintaining the pressure in the polycondensation reactor at a pressure lower than the standard pressure. When the intrinsic viscosity (IV) of the reactants in the polycondensation reactor reached 0.6 dl / g, the reactants were then discharged from the reactor. The polycondensation reaction was then carried out for 8 hours. Subsequently, the discharged reactants were subjected to a pelletization process to prepare polyester resin (copolymer) in pellet form.

[0117] The conditions for the methods used to prepare the polyester resins in Examples 1-6 and Comparative Examples 1-5 are summarized in Table 1 below. [Table 1]

[0118] [Test Example 1] The residual germanium (Ge), zinc (Zn), and phosphorus (P) content in each of the pellet-type polyester resins prepared in Examples 1-6 and Comparative Examples 1-5 was analyzed. The ratios of their content were calculated and are shown in Table 2 below. Germanium (Ge), zinc (Zn), and phosphorus (P) were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0119] [Test Example 2] The colors of the pellet-type polyester resins prepared in Examples 1-6 and Comparative Examples 1-5 were analyzed. The results are shown in Table 2 below. Color analysis was performed by measuring the chromaticity and brightness of the pellet-type polyester resins using a Varian Cary5 UV / Vis / NIR spectrophotometer equipped with a diffuse reflectance accessory. Next, transmittance data was obtained using an illuminant D65 at an observer angle of 2°. The transmittance data was processed by a color analyzer in Grams / 32 software to calculate Hunter Lab values ​​and obtain color-b values.

[0120] [Test Example 3] The process consumption rate (T) is calculated from the time taken in each reaction for preparing pellet-type polyester resin in Examples 1-6 and Comparative Examples 1-5, according to the following relationship 3. c The result was calculated. The results are shown in Table 2 below. [Relationship 3] T c (%)=(T c2 / T c1 +T c2 ) × 100

[0121] In relation 3, T c1 T is the time taken for the esterification (ES) reaction in a method for preparing polyester resin. c2 This is the time required for the polycondensation (PA) reaction in the method for preparing polyester resin.

[0122] [Test Example 4] The productivity improvement (PI) was calculated according to the following relationship 4, based on the intrinsic viscosity of the pellet-type polyester resins prepared in Examples 1-6 and Comparative Examples 1-5, and the time taken for each reaction. The results are shown in Table 2 below. [Relationship 4] PI = IV × (T c1 +T c2 / T c2 )

[0123] In relation 4, IV is the intrinsic viscosity of the polyester resin, and T c1 T is the time taken for the esterification (ES) reaction in a method for preparing polyester resin. c2 This is the time required for the polycondensation (PA) reaction in the method for preparing polyester resin. [Table 2]

[0124] Referring to Table 2 above, the polyester resins of Examples 1 to 6, in which the ratios of Ge / Zn and (Ge+Zn) / P were within the range of the present invention, exhibited excellent color properties and high productivity.

[0125] On the other hand, the polyester resin of Comparative Example 1, which did not use a zinc (Zn)-containing catalyst, and the polyester resin of Comparative Example 2, which did not use a phosphorus (P)-containing stabilizer, exhibited poor color characteristics and productivity. In particular, the color characteristics and productivity were significantly poor in Comparative Examples 3 to 5, where the ratios of Ge / Zn and (Ge+Zn) / P were outside the scope of the present invention.

Claims

1. A polyester resin comprising a diol repeating unit derived from a diol component and a dicarboxylic acid repeating unit derived from a dicarboxylic acid component, The content ratios of germanium (Ge), zinc (Zn), and phosphorus (P) are related by the following relationships 1 and 2: [Relationship 1] 1 ≤ Ge / Zn ≤ 30 [Relationship 2] 1≦(Ge+Zn) / P≦15 Satisfying Polyester resin.

2. The aforementioned diol components include 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, and 3-methyl The polyester resin according to claim 1, comprising at least one selected from the group consisting of -2,4-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol, bis(2-hydroxyethyl)terephthalate, and regenerated bis(2-hydroxyethyl)terephthalate.

3. The polyester resin according to claim 1, wherein the diol component comprises a first diol component containing ethylene glycol and a second diol component containing at least one selected from the group consisting of cyclohexanedimethanol, isosorbide, diethylene glycol, bis(2-hydroxyethyl) terephthalate, regenerated bis(2-hydroxyethyl) terephthalate, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, and 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol.

4. The polyester resin according to claim 1, wherein the germanium (Ge) is derived from a germanium (Ge)-containing catalyst, and the zinc (Zn) is derived from a zinc (Zn)-containing catalyst.

5. The polyester resin according to claim 4, wherein the germanium (Ge)-containing catalyst comprises at least one selected from the group consisting of a salt of an aliphatic carboxylic acid containing germanium (Ge), a salt of an aromatic carboxylic acid containing germanium (Ge), a salt of a halogenated carboxylic acid containing germanium (Ge), a salt of a hydroxycarbonate containing germanium (Ge), a salt of an inorganic substance containing germanium (Ge), an organic sulfonate containing germanium (Ge), an organic sulfate containing germanium (Ge), an alkoxide containing germanium (Ge), an acetylacetonate containing germanium (Ge), an oxide containing germanium (Ge), a metal containing germanium (Ge), and a hydroxide containing germanium (Ge).

6. The polyester resin according to claim 4, wherein the zinc (Zn)-containing catalyst comprises at least one selected from the group consisting of zinc acetate, zinc acetate dihydrate, zinc chloride, zinc sulfate, zinc sulfide, zinc carbonate, zinc citrate, and zinc gluconate.

7. The polyester resin according to claim 1, wherein the phosphorus (P) is derived from a phosphorus (P)-containing stabilizer.

8. The polyester resin according to claim 7, wherein the phosphorus (P)-containing stabilizer comprises at least one selected from the group consisting of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, and triethyl phosphonoacetate.

9. The polyester resin according to claim 1, wherein the dicarboxylic acid component comprises at least one selected from the group consisting of isophthalic acid, terephthalic acid, dimethyl isophthalate, phthalic acid, dimethyl phthalate, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylate, diphenyl dicarboxylic 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.

10. The polyester resin according to claim 1, having a col-b value of -4 to +4 in pellet form.

11. A method for preparing polyester resin, A step of supplying the diol component and the dicarboxylic acid component to the reactor, The steps include supplying at least one of a germanium (Ge)-containing catalyst and a zinc (Zn)-containing catalyst, and a phosphorus (P)-containing stabilizer to the reactor, The steps include: preparing an oligomer by subjecting the diol component and the dicarboxylic acid component to an esterification reaction in the presence of the catalyst and the stabilizer; The steps include subjecting the oligomer to a polycondensation reaction and Includes, The content ratios of germanium (Ge), zinc (Zn), and phosphorus (P) are related by the following relationships 1 and 2: [Relationship 1] 1 ≤ Ge / Zn ≤ 30 [Relationship 2] 1≦(Ge+Zn) / P≦15 A method for preparing a polyester resin that satisfies the following conditions.

12. A method for preparing a polyester resin according to claim 11, wherein the esterification reaction is carried out at a temperature of 200 to 300°C.

13. A method for preparing a polyester resin according to claim 11, wherein the polycondensation reaction is carried out at a temperature of 220 to 300°C for 1 to 24 hours.

14. Process consumption rate (T ｃ ) However, the following relationship 3: [Relationship 3] T ｃ (%)=(T ｃ２ / T ｃ１ +T ｃ２ )×100 According to this, the percentage is less than 65%. In relation 3, T ｃ１ However, in the method for preparing the polyester resin, the time required for the esterification reaction is T ｃ２ However, in the method for preparing the polyester resin, the time required for the polycondensation reaction is A method for preparing the polyester resin according to claim 11.

15. Productivity improvement (PI) is related to the following relationship 4: [Relationship 4] PI=IV×(T ｃ１ + 4 ｃ２ / T ｃ２ ) It is 1 or more according to this, In relation 4, IV is the intrinsic viscosity of the polyester resin, and T ｃ１ However, in the method for preparing the polyester resin, the time required for the esterification reaction is T ｃ２ However, in the method for preparing the polyester resin, the time required for the polycondensation reaction is A method for preparing the polyester resin according to claim 11.

Images