Crystalline polyester resin and method for producing the same

Abstract

The present invention relates to a crystalline polyester resin and a method for preparing the same. The crystalline polyester resin has the crystallinity required for molding and / or recycling processes, while fusion during the preparation process is minimized, allowing it to have excellent productivity, moldability, recyclability, etc.

Description

Detailed description of the invention

[0001] [Technical field] The present invention relates to a crystalline polyester resin having excellent moldability and recyclability due to a controlled degree of crystallinity, and to a method for preparing the crystalline polyester resin.

[0002] [Background technology] Polyester resins are obtained by polymerization reactions of dicarboxylic acid and diol components. Because they do not contain substances harmful to the human body and are environmentally friendly, they are widely used in the manufacture of films, partitions, panels, packaging materials, containers, and the like. In particular, polyester films prepared using polyester resins have high heat resistance and a suitable thermal shrinkage rate, making them suitable for packaging and / or labeling plastic containers such as PET bottles.

[0003] At the same time, while the use of plastic containers makes everyday life more convenient, their indiscriminate disposal or excessive use has led to very serious environmental problems. Therefore, various methods are in place for recycling used plastic containers.

[0004] Methods for recycling waste plastic containers can be divided into physical recycling processes involving washing and crushing, and chemical recycling processes involving depolymerization. However, such recycling processes require pretreatment to separate waste plastics according to their type, which reduces the efficiency of the recycling process. For example, recycling a PET bottle with a polyester film label requires separating (removing) the polyester film from the PET bottle. This is due to the difference in crystallinity between the polyester resin contained in the polyester film and the PET component contained in the PET bottle, which makes the recycling process ineffective when applied to PET bottles with polyester film attached.

[0005] Therefore, attempts have been made to prepare a polyester film having a degree of crystallinity close to that of a PET bottle by controlling the degree of crystallinity of the polyester resin. However, there are limitations to the optimization of the degree of crystallinity of such a polyester resin, and due to problems such as fusion occurring between polyester resins (e.g., polyester resin pellets) during the process of controlling the degree of crystallinity, the productivity and processability of the crystalline polyester resin are low.

[0006] [Disclosure of the Invention] [Technical Problem] To solve the above problems in the prior art, the inventors of the present invention have conducted various studies. As a result, it has been found that by controlling the heat of fusion (ΔH) at the melting point of the crystalline polyester resin, the degree of crystallinity of the polyester resin can be optimized, thereby obtaining a crystalline polyester resin having excellent productivity, moldability, and recyclability.

[0007] Therefore, an object of the present invention is to provide a crystalline polyester resin having an optimized degree of crystallinity and a method for preparing the same.

[0008] [Solution to the Problem] To achieve the above object, the present invention provides a crystalline polyester resin comprising a diol repeating unit derived from a diol component and a dicarboxylic acid repeating unit derived from a dicarboxylic acid component. When this crystalline polyester resin is analyzed by differential scanning calorimetry (DSC) while increasing the temperature to 280°C at a scan rate of 10°C / min, two or more melting points (T m ) appear, and the following relationship 1: [Relationship 1] 4 < X / Y < 70 is satisfied.

[0009] In relationship 1, X is the total heat of fusion (ΔH) at the melting points that appear at 200°C or higher, and Y is the total heat of fusion (ΔH) at the melting points that appear below 200°C.

[0010] Furthermore, the present invention provides a method for preparing a crystalline polyester resin, the method comprising (1) polymerizing a diol component and a dicarboxylic acid component to prepare a polyester resin; and (2) crystallizing the polyester resin once or multiple times, and when the crystalline polyester resin is analyzed by differential scanning calorimetry (DSC) while raising the temperature to 280°C at a scanning rate of 10°C / min, two or more melting points (T m ) appears, satisfying relation 1 above.

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

[0012] [Advantageous effects of the invention] The present invention provides a crystalline polyester resin having the degree of crystallinity required in molding (post-processing) and recycling processes. Therefore, when preparing articles (e.g., injection-molded articles) from this resin, or when recycling the prepared articles, excellent moldability and recyclability can be achieved.

[0013] Furthermore, since the present invention prepares crystalline polyester resin by one or more crystallization steps at optimally controlled temperatures in each step, it is possible to minimize the occurrence of fusion between polyester resins during the crystallization step. As a result, it is possible to improve the productivity and processability of the crystalline polyester resin. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a flowchart showing the procedure for preparing a crystalline polyester resin according to an embodiment of the present invention.

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

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

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

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

[0019] Generally, polyester resins prepared by extrusion molding and pelletization such as underwater cutting contain moisture. Therefore, when used to mold articles, it is necessary to remove the moisture contained in the polyester resin. If molding is carried out without removing the moisture, the quality of the articles prepared by molding deteriorates due to a decrease in the degree of polymerization caused by hydrolysis reactions by the moisture.

[0020] Therefore, before the polyester resin is supplied to the molding step, a drying step is performed to remove moisture contained in the polyester resin. However, polyester resins mainly have amorphous surfaces, and therefore, when they are placed in a dryer to dry them, they fuse together or stick to the inner wall of the dryer, which is problematic as it reduces the drying efficiency and productivity of the polyester resin.

[0021] To solve this problem, attempts have been made to crystallize the polyester resin to prevent fusion during the drying process. However, there are currently limitations in optimizing the degree of crystallinity of the polyester resin.

[0022] In particular, if the crystallization of the polyester resin is insufficient, or conversely, excessive, the above-mentioned fusion problem will not be resolved. For example, if excessive crystallization occurs, i.e., if the crystallization temperature is increased, melting of the polyester resin (e.g., polyester resin pellets) occurs between the exothermic and endothermic temperatures, and the fusion ratio of the polyester resin increases (the polyester resin pellets stick together). Furthermore, the processing temperature of crystalline polyester resin requires energy equal to the area of ​​the melting point and heat of fusion. Excessively crystallized polyester resin has a considerably high heat of fusion, so a large amount of energy is consumed when processing it, which reduces the processability in post-processing. Therefore, in order to improve the moldability of crystalline polyester resin after the crystallization procedure, it is very important to control the melting point and heat of fusion of the crystalline polyester resin. Furthermore, in order to improve the recyclability of polyester resin, it is also necessary to optimize the degree of crystallinity of the polyester resin, which can also be achieved by controlling the melting point and heat of fusion of the polyester resin.

[0023] Based on the above, the present invention optimizes the degree of crystallinity of the crystalline polyester resin obtained after crystallization without causing fusion between polyester resins during the crystallization procedure, thereby ensuring productivity, moldability (processability), and recyclability. For this purpose, the preparation (crystallization) process of the crystalline polyester resin is controlled, while the correlation between the melting point and heat of fusion of the crystalline polyester resin is identified, which will be described in detail below.

[0024] (Crystalline polyester resin) The crystalline polyester resin according to the present invention comprises diol repeating units derived from a diol component and dicarboxylic acid repeating units derived from a dicarboxylic acid component. When the crystalline polyester resin is analyzed by differential scanning calorimetry (DSC) while increasing the temperature to 280°C at a scanning rate of 10°C / min, two or more melting points (T) are found. m ) appears, and the following relation 1 is satisfied. [Relationship 1] 4 <X / Y<70

[0025] In relation 1, X is the total heat of fusion (ΔH) at the melting point that appears above 200°C in the DSC analysis, and Y is the total heat of fusion (ΔH) at the melting point that appears below 200°C in the DSC analysis.

[0026] According to the present invention, when a crystalline polyester resin is analyzed by DSC, two or more (specifically, two or more, three or more, four or more, or 2-3) melting points (T m ) appears and satisfies the above relationship 1 based on a specific temperature (melting point) of 200°C; therefore, its degree of crystallinity can be optimized, resulting in excellent moldability and recyclability. The temperature of 200°C is the crystallization temperature (T) of crystalline polyester resin. c ) and melting point (T m This can refer to an intermediate value between ) and ). When this intermediate temperature is adopted, the amount of heat (melting point) required for crystallization and post-processing can be optimally controlled.

[0027] Specifically, the X / Y ratio in relation 1 may be 4.1-69.9, 4.5-69.8, 5-69.7, 5.1-69.6, 5.3-69.5, 5.5-69, 5.8-68, 6-67, 6.3-66, 6.5-65, 6.8-60, 7-55, 7.5-50, 8-45, 8.5-40, 9-38, or 10-35. When the X / Y ratio is controlled within the above range, a crystalline polyester resin with a desired degree of crystallinity and minimized fusion can be provided.

[0028] According to the present invention, in a crystalline polyester resin, two or more melting points (T) are obtained by DSC analysis.m ) may appear in a temperature range of 140 to 245 °C. More specifically, two or more melting points (T m ) may be 140 to 243 °C, 140 to 242 °C, 140 to 240 °C, 140.1 to 239.5 °C, 140.1 to 239 °C, 140.2 to 238.7 °C, 140.2 to 238.5 °C, 141 to 238.3 °C, 142 to 238 °C, 145 to 237.5 °C, 148 to 237 °C, 150 to 236.8 °C, 151 to 236.5 °C, 153 to 236.3 °C, 155 to 236 °C, or 158 to 236 °C. When two or more melting points (T m ) appear within the above temperature range, a crystalline polyester resin having a desired degree of crystallinity can be provided.

[0029] In the DSC analysis of the crystalline polyester resin according to the present invention, one or more, two or more, or three or more melting points may appear at a temperature below 200 °C, and one or more or two or more melting points may appear at a temperature of 200 °C or higher.

[0030] Specifically, in the DSC analysis of the crystalline polyester resin, the first melting point (T m1 ) may appear at a temperature below 200 °C, and the second melting point (T m2 ) may appear at a temperature of 200 °C or higher. For example, in the DSC analysis of the crystalline polyester resin, the first-first melting point (T m1-1 ) and the first-second melting point (T m1-2 ) may appear at a temperature below 200 °C, and the second melting point (T m2 ) may appear at a temperature of 200 °C or higher. Specifically, the first-first melting point (T m1-1 ) may be 140 to 198 °C, 141 to 195 °C, 145 to 193 °C, or 150 to 190 °C. Specifically, the first-second melting point (T m1-2 ) may be above 185 to 210 °C, 187 to 205 °C, 188 to 200 °C, or 189 to 195 °C. Specifically, the second melting point (T m2 ) may be above 210 to 245 °C, 215 to 243 °C, 218 to 242 °C, or 220 to 240 °C.

[0031] According to the present invention, the first melting point (T m1 ) and the second melting point (T m2 The difference between (|T) m1 -T m2 |) may be between 40 and 105°C. Specifically, the difference (|T m1 -T m2 |) may be 43~105℃, 45~103℃, 48~103℃, 50~101℃, 52~99℃, 54~98.8℃, 54.5~98.5℃, 55~95℃, 56~93℃, 57~90℃, 57.5~85℃, 58~80℃, 59~75℃, or 60~70℃. Difference (|T m1 -T m2 In the calculation of |), the first melting point (T m1 If there are two or more melting points, the lowest melting point among the two or more melting points is the first melting point (T m1 ) and the second melting point (T m2 If there are two or more melting points, the highest temperature among the two or more melting points is the second melting point (T m2 )

[0032] According to the present invention, if, in DSC analysis, one or more melting points appear above 200°C while the temperature is raised to 280°C at a scanning rate of 10°C / min, then X in relation 1 is the sum of the heats of fusion (ΔH) at each melting point (ΔH sum1 ) can refer to the melting point a(T ma ) and melting point b(T mb If the two melting points of ) appear above 200°C, then X has a melting point a(T ma ) Heat of fusion (ΔH a ) and melting point b(T mb ) Heat of fusion (ΔH b ) sum (ΔH a +ΔH b ) can be set as follows: Here, in DSC analysis, the melting point a(T ma If one of the melting points of ) appears to be above 200°C, then X is a melting point a(T ma ) Heat of fusion (ΔH aThe value of X (the sum of the heat of fusion (ΔH) at the melting point that appears above 200°C) is not particularly limited, but may be 20 J / g or more, specifically 20.2 J / g or more, 23 J / g or more, 24 J / g or more, 25 J / g or more, 27 J / g or more, 29 J / g or more, 30 J / g or more, 31 J / g or more, 33 J / g or more, 35 J / g or more, 37 J / g or more, or 40 J / g or more (for example, 20-39 J / g, 22-38 J / g, 24-37 J / g, or 25-35 J / g). When the X value is within the above range, a crystalline polyester resin having the desired degree of crystallinity can be provided.

[0033] According to the present invention, if, in DSC analysis, one or more melting points appear below 200°C while the temperature is raised to 280°C at a scanning rate of 10°C / min, then Y in relation 1 is the sum of the heats of fusion (ΔH) at each melting point (ΔH sum2 ) can refer to the melting point c(T mc ) and melting point d(T md If the two melting points of ) appear below 200°C, then Y is melting point c(T mc ) Heat of fusion (ΔH c ) and melting point d(T md ) Heat of fusion (ΔH d ) sum (ΔH c +ΔH d ) can be set as follows: Here, in DSC analysis, the melting point c(T mc If one of the melting points of ) appears below 200°C, then Y is a melting point c(T mc ) Heat of fusion (ΔH c The Y value (the sum of the heat of fusion (ΔH) at the melting point appearing below 200°C) is not particularly limited, but may be 0.1 to 10 J / g, specifically 0.2 to 9.5 J / g, 0.3 to 9.3 J / g, 0.5 to 9 J / g, 1 to 8.5 J / g, 2.5 to 8 J / g, 3 to 7.8 J / g, 3.3 to 7.5 J / g, 3.5 to 7 J / g, 3.8 to 6.5 J / g, 4 to 6 J / g, 4.2 to 5.8 J / g, or 4.4 to 5.5 J / g. When the Y value is within the above range, a crystalline polyester resin having the desired degree of crystallinity can be provided.

[0034] On the other hand, according to the present invention, the crystalline polyester resin contains repeating diol units derived from the diol component. The diol component is not particularly limited as long as it is a generally known diol component. Specifically, this includes bis-2-hydroxyethyl terephthalate, isosorbide, neopentyl glycol, ethylene glycol, diethylene glycol, cyclohexanedimethanol, 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 It may also contain at least one (for example, two or more, three or more, four or more, or five or more) selected from the group consisting of 4-cyclohexanediol, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate (CHDM derivative), 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol (CHDM derivative), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), regenerated bis-2-hydroxyethyl terephthalate, regenerated isosorbide, regenerated neopentyl glycol, regenerated ethylene glycol, regenerated diethylene glycol, and regenerated cyclohexanedimethanol.

[0035] Here, the recycled bis-2-hydroxyethyl terephthalate, recycled isosorbide, recycled neopentyl glycol, recycled ethylene glycol, recycled diethylene glycol, and recycled cyclohexanedimethanol used as diol components may refer to, but are not limited to, recycled raw materials (monomers) obtained by performing generally known depolymerization processes on waste polyester resin or used waste polyester articles.

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

[0037] The amount of the first diol component used (the amount added to the reaction) is not particularly limited, but may be 50-99 mol%, 60-99 mol%, 70-99 mol%, 70-98 mol%, 75-98 mol%, 75-97 mol%, or 80-90 mol%, based on the total molar percentage of the diol component. Therefore, the crystalline 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 crystalline polyester resin with excellent basic physical properties can be produced economically.

[0038] The amount of the second diol component used (the amount added to the reaction) is not particularly limited, but may be 5-99 mol%, 5.5-95 mol%, 10-90 mol%, 15-80 mol%, 20-80 mol%, 25-75 mol%, or 30-70 mol%, based on the total molar percentage of the diol component. Therefore, the crystalline 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 crystalline polyester resin having the required level of viscosity in the molding process. As a result, articles (molded articles) of excellent quality can be provided.

[0039] The amount of the third diol component used (the amount added to the reaction) is not particularly limited, but may be 20 mol% or less based on the total molar percentage of the diol component. Specifically, the amount of the third diol component used may be 1-20 mol%, 2-20 mol%, 2.5-19 mol%, 3-18 mol%, 3-17.5 mol%, 4-17 mol%, 4-16 mol%, or 4.5-15 mol%, based on the total molar percentage of the diol component. Therefore, the crystalline polyester resin may contain repeating units (c) derived from the third diol component. When the amount of the third diol component used is within the above range, a crystalline polyester resin with excellent moldability (processability) and excellent basic physical properties can be produced.

[0040] For example, when considering the basic physical properties and moldability (processability) of a crystalline polyester resin, the amount of isosorbide or recycled isosorbide used among the third diol components may be 0-8 mol%, 0.1-6 mol%, 0.3-4 mol%, or 0.4-3.5 mol%, based on the total mole percent of the diol components. Furthermore, the amount of diethylene glycol or recycled diethylene glycol used among the third diol components may be 0.5-10 mol%, 1-7 mol%, 1.5-5 mol%, or 2-4 mol%, based on the total mole percent of the diol components. Furthermore, the amount of cyclohexanedimethanol or recycled cyclohexanedimethanol used among the third diol components may be 0-14 mol%, 1-12 mol%, 2-10 mol%, or 3-9 mol%, based on the total mole percent of the diol components.

[0041] According to the present invention, the crystalline 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 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, azelaic acid, regenerated terephthalic acid, regenerated dimethyl terephthalate, regenerated isophthalic acid, and regenerated phthalic acid.

[0042] Here, the recycled terephthalic acid, recycled dimethyl terephthalate, recycled isophthalic acid, and recycled phthalic acid used as dicarboxylic acid components may refer to, but are not limited to, recycled raw materials (monomers) obtained by performing a generally known depolymerization process on waste polyester resin or used waste polyester articles.

[0043] More specifically, the dicarboxylic acid component may include at least one selected from the group consisting of: a first dicarboxylic acid component comprising terephthalic acid (TPA), dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate (DMT), regenerated terephthalic acid (r-TPA), regenerated dimethyl terephthalate (r-DMT), or a combination thereof; and a second dicarboxylic acid component comprising isophthalic acid, phthalic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 1,3-cyclohexanedicarboxylate, regenerated isophthalic acid, regenerated phthalic acid, or a combination thereof.

[0044] The amount of the first dicarboxylic acid component used (the amount added to the reaction) is not particularly limited, but may be 95 mol% or more, 96 mol% or more, 97 mol% or more, 98 mol% or more, or 99 mol% or more (for example, 95-100 mol%, over 95-100 mol%, 96-99.5 mol%, 97-99 mol%, or 98-98.5 mol%) based on the total molar percentage of the dicarboxylic acid component. Therefore, the crystalline polyester resin may contain repeating units (z) derived from the first dicarboxylic acid component.

[0045] The amount of the second dicarboxylic acid component used (the amount added to the reaction) is not particularly limited, but may be 5 mol% or less, 4 mol% or less, 3 mol% or less, 2 mol% or less, or 1 mol% or less (for example, 0 to 5 mol%, greater than 0 to 4.5 mol%, 0.5 to 4 mol%, 1 to 3 mol%, or 1.5 to 2 mol%) based on the total molar percentage of the dicarboxylic acid component. Therefore, the crystalline polyester resin may contain repeating units (w) derived from the second dicarboxylic acid component.

[0046] The crystalline polyester resin according to the present invention may further contain repeating units (A) derived from a branching agent having three or more functional groups. Thanks to the branching agent, the repeating units (A) are introduced into the side chains of the main chain, or a graft polymerization structure is formed by the repeating units (A), so that the crystalline polyester resin can have a high molecular weight and a high degree of crystallinity.

[0047] According to the present invention, the content of repeating units (A) contained in the crystalline polyester resin is not particularly limited, but may be 0.001 to 15% by weight, 0.005 to 13% by weight, 0.01 to 12% by weight, 0.02 to 10% by weight, or 0.03 to 5% by weight, based on the total weight percentage of diol repeating units.

[0048] The branching agent is not particularly limited, but may specifically be trimellitic acid, trimellitic anhydride, trimethylolpropane, or a combination thereof.

[0049] According to the present invention, the crystalline polyester resin may have an intrinsic viscosity (IV) of 0.5 to 1.3 dl / g (at 35°C). Specifically, the intrinsic viscosity (IV) of the crystalline polyester resin at 35°C may be 0.51 to 1.3 dl / g, 0.53 to 1.29 dl / g, 0.56 to 1.28 dl / g, 0.56 to 1.27 dl / g, 0.59 to 1.25 dl / g, or 0.6 to 1.25 dl / g.

[0050] According to the present invention, the crystalline polyester resin may have a fusion ratio of 5% or less, according to the following relationship 2. Specifically, the fusion ratio of the crystalline polyester resin may be 4.8% or less, 4.6% or less, 4.5% or less, 4.3% or less, 4% or less, 3.8% or less, 3.5% or less, 3.3% or less, 3% or less, 2.5% or less, 2.3% or less, 2% or less, 1.8% or less, 1.5% or less, 1% or less, 0.8% or less, 0.5% or less, 0.3% or less, or 0.1% or less (for example, 0.001 to 5%, 0.005 to 4%, 0.01 to 3%, or 0.1 to 2%). As a result, the productivity of the crystalline polyester resin is excellent, while at the same time, moldability (processability) can be ensured during the molding process of the crystalline polyester resin. [Relationship 2] Fusion ratio (%) = (W F / W T ) × 100

[0051] In relation 2, W T This is the total weight of crystalline polyester resin produced per unit time (1 hour), W F This is the weight of fused material produced per ton of crystalline polyester resin manufactured.

[0052] The fused material is one that cannot pass through a vibrator with a 12.5 mm mesh.

[0053] The crystalline polyester resin according to the present invention may be in the form (shape) of chips, pellets, or powder.

[0054] Furthermore, the crystalline polyester resin according to the present invention may be a homopolymer or a copolymer. Specifically, the crystalline 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).

[0055] (Method for preparing crystalline polyester resin) The method for preparing a crystalline polyester resin according to the present invention comprises the steps of (1) polymerizing a diol component and a dicarboxylic acid component to prepare a polyester resin, and (2) crystallizing the polyester resin once or multiple times, and when the crystalline polyester resin prepared in steps (1) and (2) is analyzed by differential scanning calorimetry (DSC) while raising the temperature to 280°C at a scanning rate of 10°C / min, two or more melting points (T m ) appears and satisfies the following relationship 1. The method for preparing a crystalline polyester resin according to the present invention is characterized by controlling the crystallization temperature stepwise in step (2). By controlling the degree of crystallization to satisfy the following relationship 1, it is possible to prepare a crystalline polyester resin with excellent moldability and recyclability. This will be explained in detail below with reference to Figure 1. Here, the explanation of relationship 1 below is the same as that described above and will therefore be omitted. [Relationship 1] 4 <X / Y<70

[0056] In relation 1, X is the total heat of fusion (ΔH) at the melting point that appears above 200°C, and Y is the total heat of fusion (ΔH) at the melting point that appears below 200°C.

[0057] [Step (1): Preparation of polyester resin] Step (1) involves esterifying (or transesterifying) the diol component and the dicarboxylic acid component to obtain a reactant (e.g., an oligomer), and then polycondensing this reactant to prepare a polyester resin (e.g., a polyester resin with a non-crystalline surface). Here, the diol component and the dicarboxylic acid component are the same as those described above, so a detailed explanation is omitted.

[0058] The conditions under which the esterification reaction (or transesterification reaction) takes place are not particularly limited. Specifically, the temperature at which the esterification reaction takes place may be 220-300°C, 225-290°C, 230-280°C, 235-275°C, 240-270°C, or 245-265°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 , 0.5~2.5 kgf / cm 2 , or 1-2 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, while reactants (oligomers) with the desired molecular weight can be obtained in high yield.

[0059] In addition to the diol and dicarboxylic acid components, at least one additive selected from the group consisting of catalysts, colorants, crystallizers, antioxidants, and branching agents may be supplied to the reactor in which the esterification (or transesterification) reaction takes place.

[0060] The catalyst may be sodium and magnesium methylates; acetates, borates, fatty acid salts, or carbonates of Ge, Zn, Cd, Mn, Co, Ca, and Ba; and oxides or hydrates of Ge, Mg, Pb, Mn, Ti, Sb, Sn, and Al. 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, ethyl acetoacetate titanate, isostearyl titanate, titanium dioxide, germanium dioxide, germanium tetrachloride, germanium ethylene glycoside, germanium acetate, or a combination thereof.

[0061] Organic compounds such as cobalt compounds, anthraquinone compounds, perinone compounds, azo compounds, and methine compounds (for example, cobalt acetate, cobalt propionate, Clariant's Polysynthren Blue RLS toner, and Clariant's Solvaperm Red BB toner) may be used as colorants.

[0062] As a crystallizing agent, crystal nucleating agents, ultraviolet absorbers, polyolefin resins, polyamide resins, etc., may be used.

[0063] Hindered phenol compounds, phosphate compounds, thioether compounds, etc., may be used as antioxidants.

[0064] As branching agents, trimellitic acid, trimellitic anhydride, trimethylolpropane, or combinations thereof, as described above, may be used.

[0065] The reactants obtained by the esterification reaction (or transesterification reaction) may then be supplied to a polycondensation reactor to carry out a polycondensation reaction. 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 240-320°C, 245-310°C, 250-300°C, 255-295°C, or 265-290°C. Furthermore, the pressure at which the polycondensation reaction takes place may be lower than atmospheric pressure (e.g., 1 atm) (reduced pressure). By carrying out the polycondensation reaction under the above conditions, polyester resins (polymers) with excellent moldability (processability) can be efficiently produced.

[0066] Subsequently, the polyester resin obtained by the polycondensation reaction may be pelletized by procedures such as extrusion molding and underwater cutting. In other words, the polyester resin may be polyester resin pellets.

[0067] The polyester resin obtained in step (1) above (for example, polyester resin pellets) may be subjected to the following step (2) to have a desired degree of crystallinity. Here, a drying process may be performed on the polyester resin before step (2) is performed. That is, the method for preparing a crystalline polyester resin according to the present invention may further include a step of drying the polyester resin obtained in step (1) between step (1) and step (2) in order to further optimize the degree of crystallinity of the crystalline polyester resin while preventing fusion between polyester resins.

[0068] The drying of the polyester resin may be carried out using a conventionally known dryer (e.g., a fluidized bed dryer). The conditions under which drying is carried out are not particularly limited, but considering the drying efficiency and productivity of the polyester resin, drying may be carried out at 40-90°C (specifically 40-85°C, 45-85°C, 50-80°C, or 50-70°C) for 3-12 hours (specifically 4-12 hours or 5-11 hours).

[0069] [Step (2): Preparation of crystalline polyester resin by crystallization] Step (2) is a step of crystallizing the polyester resin obtained in step (1) one or more times. Specifically, the crystallization of the polyester resin may be carried out two or more times, three or more times, or four or more times.

[0070] According to the present invention, the temperature at which crystallization is carried out is not particularly limited, but it may be 105 to 185 °C (specifically, 106 to 184 °C, 107 to 183 °C, 108 to 182 °C, 109 to 181 °C, or 110 to 180 °C). When crystallization is carried out within the above range, a crystalline polyester resin having an optimized degree of crystallinity can be prepared while minimizing the fusion between polyester resins during the crystallization procedure.

[0071] Furthermore, according to the present invention, crystallization may be carried out under temperature conditions that increase step by step. Specifically, when crystallization is carried out in the first and second stages, the second crystallization temperature (T2) may be higher than the first crystallization temperature (T1) (T1 < T2). Furthermore, when crystallization is carried out in the first to third stages, the third crystallization temperature (T3) may be higher than the second crystallization temperature (T2), and the second crystallization temperature (T2) may be higher than the first crystallization temperature (T1) (T1 < T2 < T3). When crystallization is carried out under temperature conditions that increase step by step, a crystalline polyester resin having an optimized degree of crystallinity can be prepared while minimizing the fusion between polyester resins during the crystallization procedure.

[0072] According to the present invention, step (2) may specifically include: (2-1) a step of performing a first crystallization of the polyester resin from step (1) at 105 to 135°C (specifically, 108 to 133°C or 110 to 130°C); (2-2) a step of performing a second crystallization of the polyester resin crystallized in step (2-1) at 120 to 175°C (specifically, 120 to 170°C or 125 to 155°C); and (2-3) a step of performing a third crystallization of the polyester resin crystallized in step (2-2) at 140 to 180°C (specifically, 145 to 180°C or 150 to 180°C). When crystallization is performed in three stages and each crystallization temperature is controlled within the above specific ranges, crystals are formed uniformly on the inside and outside of the polyester resin, and at the same time, fusion between polyester resins caused by surface melting during the crystallization procedure can be minimized. Therefore, polyester resins with optimized crystallinity can be efficiently prepared (by improving productivity), thereby achieving crystalline polyester resins with excellent moldability and recyclability.

[0073] Here, the first crystallization temperature, the second crystallization temperature, and the third crystallization temperature may be different from each other.

[0074] Crystallization may be carried out under atmospheric pressure or reduced pressure. Generally known fluidizers may be added to the crystallization procedure to increase the fluidity of the polyester resin (polyester resin pellets).

[0075] The crystalline polyester resin prepared by crystallization in step (2) as described above may be further subjected to generally known solid-phase polymerization procedures as needed to control its viscosity and molecular weight.

[0076] (Goods) Articles according to the present invention are prepared from the above-mentioned crystalline polyester resin. Specifically, articles according to the present invention can be prepared by performing molding processes such as injection molding, extrusion molding, extrusion blow molding, injection blow molding, pressure molding, or vacuum molding on a crystalline polyester resin. For example, the article may be an injection-molded article prepared by injection molding.

[0077] Since the articles are prepared from the above-mentioned crystalline polyester resin, they can possess excellent quality (e.g., heat resistance, mechanical strength, appearance, etc.). Furthermore, because the articles are prepared from the above-mentioned crystalline polyester resin, the recycling process can be highly efficient if it is carried out after use.

[0078] The articles are not particularly limited, but may include films; sheets; or small or large containers (for example, containers for cosmetics, food, etc.).

[0079] [Mode of the 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.

[0080] [Example 1] [Step (1): Preparation of polyester resin] Regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 2,515.3 kg), terephthalic acid (TPA, 6,575.6 kg), isosorbide (ISB, 309.8 kg), ethylene glycol (EG, 2,624.5 kg), 1,4-cyclohexanedimethanol (CHDM, 633.8 kg), diethylene glycol (DEG, 70.0 kg), Ge catalyst (1.0 kg), Ti catalyst (1.0 kg), phosphoric acid (1.5 kg), blue toner (0.01 kg), and red toner (0.005 kg) were charged into a reactor equipped with a column and a condenser that could be cooled with water. Next, the reactor temperature was raised to 265°C, and then a pressure of 2 kgf / cm² was applied at 265°C. 2An esterification reaction (ES) was carried out under pressure to obtain a transparent reactant.

[0081] Subsequently, the reactants were transferred to a polycondensation reactor, and a 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 (melt intrinsic viscosity) (IV) of the reactants in the polycondensation reactor reached 0.60 dl / g, the reactants were discharged to the outside of the polycondensation reactor to form strands. These strands were then solidified with a cooling liquid and pelletized so that the average weight of 100 pellets was approximately 1.0 to 2.5 g, thereby obtaining polyester resin pellets.

[0082] The polyester resin pellets obtained in this manner were then dried at 50°C for 10 hours before crystallization.

[0083] [Step (2): Crystallization of polyester resin] Dried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such events, the first crystallization of the polyester resin pellets was carried out at 110°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 130°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 165°C.

[0084] [Example 2] [Step (1): Preparation of polyester resin] Terephthalic acid (TPA, 8,462.5 kg), ethylene glycol (EG, 4,874.5 kg), 1,4-cyclohexanedimethanol (CHDM, 326.3 kg), diethylene glycol (DEG, 72.1 kg), Ti catalyst (1.0 kg), phosphoric acid (1.5 kg), blue toner (0.01 kg), and red toner (0.01 kg) were charged into a reactor equipped with a column and a condenser that could be cooled with water. Next, the reactor temperature was raised to 255°C, and then a pressure of 1 kgf / cm² was applied at 255°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 a 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 (molten intrinsic viscosity) (IV) of the reactants in the polycondensation reactor reached 0.50 dl / g, the reactants were discharged to the outside of the polycondensation reactor to form strands. These strands were then solidified with a cooling liquid and pelletized so that the average weight of 100 pellets was approximately 1.0 to 2.5 g, thereby obtaining polyester resin pellets.

[0086] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 115°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 120°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 160°C.

[0087] [Example 3] [Step (1): Preparation of polyester resin] Regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 6,569.4 kg), terephthalic acid (TPA, 8,157.5 kg), isophthalic acid (IPA, 429.3 kg), ethylene glycol (EG, 2,180.8 kg), diethylene glycol (DEG, 109.7 kg), Ge catalyst (1.0 kg), and phosphoric acid (1.5 kg) were charged into a reactor equipped with a column and a condenser that could be cooled with water. 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.

[0088] Subsequently, the reactants were transferred to a polycondensation reactor, and a 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 (molten intrinsic viscosity) (IV) of the reactants in the polycondensation reactor reached 0.78 dl / g, the reactants were discharged to the outside of the polycondensation reactor to form strands. These strands were then solidified with a cooling liquid and pelletized so that the average weight of 100 pellets was approximately 1.0 to 2.5 g, thereby obtaining polyester resin pellets.

[0089] The polyester resin pellets obtained in this manner were then dried at 40°C for 9 hours before crystallization.

[0090] [Step (2): Crystallization of polyester resin] Dried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 120°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 135°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 150°C.

[0091] [Example 4] [Step (1): Preparation of polyester resin] Regenerated bis-2-hydroxyethyl terephthalate (r-BHET, 5,125.6 kg), terephthalic acid (TPA, 5,024.7 kg), isosorbide (ISB, 52.6 kg), ethylene glycol (EG, 2,229.7 kg), 1,4-cyclohexanedimethanol (CHDM, 484.3 kg), diethylene glycol (DEG, 71.3 kg), Ge catalyst (1.0 kg), phosphoric acid (1.5 kg), cobalt acetate (0.4 kg), blue toner (0.03 kg), and red toner (0.01 kg) were charged into a reactor equipped with a column and a condenser that could be cooled with water. 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.

[0092] Subsequently, the reactants were transferred to a polycondensation reactor, and a 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 (molten intrinsic viscosity) (IV) of the reactants in the polycondensation reactor reached 0.85 dl / g, the reactants were discharged to the outside of the polycondensation reactor to form strands. These strands were then solidified with a cooling liquid and pelletized so that the average weight of 100 pellets was approximately 1.0 to 2.5 g, thereby obtaining polyester resin pellets.

[0093] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 110°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 170°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 180°C.

[0094] [Example 5] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 1. These polyester resin pellets were then dried at 55°C for 4 hours before crystallization.

[0095] [Step (2): Crystallization of polyester resin] Dried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such events, the first crystallization of the polyester resin pellets was carried out at 125°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 130°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 140°C.

[0096] [Example 6] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 3.

[0097] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 130°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 150°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 180°C.

[0098] [Comparative Example 1] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 3.

[0099] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while decreasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 160°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 140°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 120°C.

[0100] [Comparative Example 2] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 3. These polyester resin pellets were then dried at 55°C for 3 hours before crystallization.

[0101] [Step (2): Crystallization of polyester resin] Dried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out three times while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 140°C, the second crystallization of the first crystallized polyester resin pellets was carried out at 160°C, and the third crystallization of the second crystallized polyester resin pellets was carried out at 200°C.

[0102] [Comparative Example 3] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 4.

[0103] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 100°C, the second crystallization of the first crystalline polyester resin pellets was carried out at 160°C, and the third crystallization of the second crystalline polyester resin pellets was carried out at 190°C.

[0104] [Comparative Example 4] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 1.

[0105] [Step (2): Crystallization of polyester resin] Undried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out once at 170°C to obtain crystalline polyester resin.

[0106] [Comparative Example 5] [Step (1): Preparation of polyester resin] Polyester resin pellets were obtained using the same procedure as in Example 3. These polyester resin pellets were then dried at 40°C for 3 hours before crystallization.

[0107] [Step (2): Crystallization of polyester resin] Dried polyester resin pellets were supplied to a crystallization reactor at a rate of 1 ton / hour (supply rate: 1 ton / hour), and the crystallization procedure was carried out twice while increasing the temperature according to the position of the polyester resin pellets, thereby obtaining crystalline polyester resin. In such an event, the first crystallization of the polyester resin pellets was carried out at 70°C, and the second crystallization of the first crystallized polyester resin pellets was carried out at 160°C.

[0108] [Test Example 1] The crystalline polyester resins prepared in Examples 1-6 and Comparative Examples 1-5 were analyzed by differential scanning calorimetry (DSC) to determine their melting points (T m We determined whether the following appeared. The results are shown in Tables 1 and 2 below. DSC analysis was performed as follows.

[0109] DSC analysis device: Mettler Toledo's DSC 1 model was used.

[0110] Sample preparation: Approximately 6-10 mg of each crystalline polyester resin was taken and placed in an aluminum dish.

[0111] Scan 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.

[0112] Melting point (T m Determination of the melting point: In the resulting DSC curve, the temperature at which an endothermic peak appeared during the temperature increase procedure was defined as the melting point. Subsequently, the melting point (T m The heat of fusion (ΔH) and the X / Y ratio (rounded to two decimal places) were calculated using [a specific method / tool].

[0113] [Test Example 2] The weight (kg) of fused material per ton of total production (kg / hour) was measured, and then the fusion ratio was calculated according to the following relationship 2. The results are shown in Tables 1 and 2 below. [Relationship 2] Fusion ratio (%) = (W F / W T ) × 100

[0114] In relation 2, W T This is the total weight (total production volume) of crystalline polyester resin produced per unit time (1 hour), W F This represents the weight of fused material per ton of crystalline polyester resin produced (to separate the crystalline polyester resin samples, the total production volume was divided into 1-ton portions, and the weight of fused material contained in each sample was measured).

[0115] The fused material (a fused polyester resin material) is a material that cannot pass through a vibrator with a 12.5 mm mesh.

[0116] [Test Example 3] The crystalline polyester resins prepared in Examples 1-6 and Comparative Examples 1-5 were each injection-molded using an ENGEL 25 device at a temperature of 250-260°C to prepare injection-molded samples with a length of 100 mm, a width of 100 mm, and a thickness of 3 mm. The moldability of these samples was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below. ◎: There were no fisheyes or unmelted areas (where the resin pellets did not melt) in the injection-molded sample, and a continuous injection process was possible. ○: There were no unmelted areas in the injection-molded sample, and there was one or fewer fisheyes, allowing for a continuous injection process. △: Although there were two or more unmelted areas and fisheyes in the injection-molded sample, the continuous injection process was possible. ×: Fusion occurred between the resin pellets, making the continuous injection process impossible.

[0117] [Table 1]

[0118] [Table 2]

[0119] Referring to Table 1 above, the crystalline polyester resins of Examples 1 to 6 according to the present invention had a very low fusion ratio of 5% or less during the crystallization procedure and an X / Y ratio controlled within the range of the present invention, thereby exhibiting excellent productivity and moldability along with optimized crystallinity.

[0120] In contrast, referring to Table 2 above, the crystalline polyester resin of Comparative Example 1, in which crystallization was performed under conditions of gradual temperature reduction, and the crystalline polyester resins of Comparative Examples 2 and 3, in which the crystallization temperature was outside the range of the present invention, had a fusion ratio exceeding 5%, resulting in insufficient productivity of the crystalline polyester resin. Furthermore, it was confirmed that in Comparative Examples 1 to 3, excessive crystallization led to fisheyes and unmelted areas during the injection molding process, resulting in insufficient moldability. Moreover, in the crystalline polyester resin of Comparative Example 4, in which crystallization was performed once at a low temperature, and the crystalline polyester resin of Comparative Example 5, in which crystallization was performed twice (exhibiting translucency due to insufficient crystallization), the fusion ratio during the crystallization procedure was very high, making crystallization impossible or insufficient. Furthermore, in Comparative Example 5, fusion occurred between the crystalline polyester resins, resulting in insufficient moldability.

Claims

1. A crystalline polyester resin comprising diol repeating units derived from a diol component and dicarboxylic acid repeating units derived from a dicarboxylic acid component, wherein when the crystalline polyester resin is analyzed by differential scanning calorimetry (DSC) while increasing the temperature to 280°C at a scanning speed of 10°C / min, two or more melting points (T ｍ ) appears, and the following relationship 1 [Relationship 1] 4 < X / Y < 70 A crystalline polyester resin that satisfies the following conditions, and in relation 1, X is the total heat of fusion (ΔH) at the melting point that appears at 200°C or higher, and Y is the total heat of fusion (ΔH) at the melting point that appears at less than 200°C.

2. The melting point (T ｍ The crystalline polyester resin according to claim 1, wherein the temperature is 140 to 245°C.

3. In the DSC analysis of the crystalline polyester resin, the first melting point (T ｍ１ ) appears at temperatures below 200°C, and the second melting point (T ｍ２ ) appears at temperatures above 200°C. The first melting point (T ｍ１ ) and the second melting point (T ｍ２ The difference between (|T) ｍ１ -T ｍ２ The crystalline polyester resin according to claim 1, wherein the temperature (|) is 40 to 105°C.

4. The crystalline polyester resin according to claim 1, wherein the total heat of fusion (ΔH) at the melting point, which appears at 200°C or higher, is 20 J / g or more.

5. The crystalline polyester resin according to claim 1, wherein the total heat of fusion (ΔH) at the melting point, which appears below 200°C, is 0.1 to 10 J / g.

6. The crystalline polyester resin according to claim 1, wherein the dicarboxylic acid component comprises at least one selected from the group consisting of 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, azelaic acid, regenerated terephthalic acid, regenerated dimethyl terephthalate, regenerated isophthalic acid, and regenerated phthalic acid.

7. The crystalline polyester resin according to claim 1, wherein the dicarboxylic acid component comprises at least one selected from the group consisting of: a first dicarboxylic acid component comprising terephthalic acid, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, regenerated terephthalic acid, regenerated dimethyl terephthalate, or a combination thereof; and a second dicarboxylic acid component comprising isophthalic acid, phthalic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl 1,3-cyclohexanedicarboxylate, regenerated isophthalic acid, regenerated phthalic acid, or a combination thereof.

8. The crystalline polyester resin according to claim 7, wherein the amount of the second dicarboxylic acid component used is 5 mol% or less based on the total mole percent of the dicarboxylic acid component.

9. The aforementioned diol component is bis-2-hydroxyethyl terephthalate, isosorbide, neopentyl glycol, ethylene glycol, diethylene glycol, cyclohexanedimethanol, 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 The crystalline polyester resin according to claim 1, comprising at least one selected from the group consisting of 1,2-cyclohexanediol, 1,4-cyclohexanediol, 4-(hydroxymethyl)cyclohexylmethyl-4-(hydroxymethyl)cyclohexanecarboxylate, 4-(4-(hydroxymethyl)cyclohexylmethoxymethyl)cyclohexylmethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, regenerated bis-2-hydroxyethyl terephthalate, regenerated isosorbide, regenerated neopentyl glycol, regenerated ethylene glycol, regenerated diethylene glycol, and regenerated cyclohexanedimethanol.

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

11. The crystalline polyester resin according to claim 10, wherein the amount of the third diol component used is 20 mol% or less based on the total mole percent of the diol component.

12. Relationship 2 below: [Relationship 2] Fusion ratio (%) = (W Ｆ / W Ｔ ) × 100 The fusion ratio is 5% or less, and in relation 2, W Ｔ W is the total weight of the crystalline polyester resin produced per unit time (1 hour). Ｆ The crystalline polyester resin according to claim 1, wherein is the weight of fused material produced per ton of the crystalline polyester resin manufactured, and the fused material is a material that cannot pass through a vibrator having a 12.5 mm mesh.

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

14. The crystalline polyester resin according to claim 13, wherein the content of the repeating units derived from the branching agent is 0.001 to 15% by weight, based on the total weight percentage of the diol repeating units.

15. The crystalline polyester resin according to claim 1, having an intrinsic viscosity (IV) of 0.5 to 1.3 dl / g.

16. (1) A step of polymerizing the diol component and the dicarboxylic acid component to prepare a polyester resin; (2) The step of crystallizing the polyester resin once or multiple times A method for preparing a crystalline polyester resin containing, When the crystalline polyester resin was analyzed by differential scanning calorimetry (DSC) while increasing the temperature to 280°C at a scanning speed of 10°C / min, two or more melting points (T) were found. ｍ ) appears, and the following relationship 1: [Relationship 1] 4 < X / Y < 70 A method that satisfies the following conditions, wherein in relation 1, X is the sum of the heats of fusion (ΔH) at the melting point that appear at 200°C or higher, and Y is the sum of the heats of fusion (ΔH) at the melting point that appear at less than 200°C.

17. A method for preparing a crystalline polyester resin according to claim 16, wherein the crystallization in step (2) is carried out in a temperature range of 105 to 185°C.

18. A method for preparing a crystalline polyester resin according to claim 16, wherein the crystallization in step (2) is carried out under conditions of gradually increasing temperature.

19. A method for preparing a crystalline polyester resin according to claim 16, wherein step (2) is (2-1) A step of performing a first crystallization of the polyester resin of step (1) at 105 to 135°C; (2-2) A step of performing a second crystallization of the polyester resin crystallized in step (2-1) at 120 to 175°C; (2-3) A third crystallization step is performed on the polyester resin crystallized in step (2-2) at 140 to 180°C. Methods that include...

20. A method for preparing a crystalline polyester resin according to claim 16, further comprising the step of drying the polyester resin obtained in step (1) before step (2) is carried out.

21. An article prepared from a crystalline polyester resin according to any one of claims 1 to 15.

22. The article according to claim 21, wherein the article is an injection-molded article.

Images