Polyester copolymer

Abstract

The present invention relates to a polyester copolymer comprising: a repeating unit A derived from a first dicarboxylic acid component comprising terephthalic acid (TPA) or dimethyl terephthalate (DMT); a repeating unit B derived from a second dicarboxylic acid component comprising dimethyl cyclohexane dicarboxylate (DMCD); and a repeating unit C derived from a diol component comprising a C2-C6 alkanediol compound, wherein the repeating unit B is included in an amount of 40 mol % or less based on the total number of moles of repeating units derived from all the dicarboxylic acid components. The polyester copolymer is environmentally friendly and has excellent mechanical properties, optical properties, and processability.

Description

Polyester copolymer

[0001] The present invention relates to an eco-friendly polyester copolymer with excellent quality and processability.

[0002] Polyvinyl chloride (PVC) is colorless, transparent, and possesses excellent strength. It is widely used in various industrial fields because its desired physical properties can be easily controlled depending on the type of additives incorporated during processing. For example, by adding a certain amount of plasticizer—a softening component—to PVC, flexible PVC can be manufactured for products such as packaging films and shower curtains. Conversely, by adding 10 weight percent or less of plasticizer, rigid PVC can be manufactured for products such as plumbing materials. As such, PVC offers excellent productivity and processability, as its flexibility and rigidity can be easily controlled simply by adjusting the plasticizer content without additional processing steps. However, the use of plasticizers is currently restricted due to recent controversies regarding the harmfulness of phthalate-based and adipic acid-based substances to the environment and human health. Furthermore, PVC has the disadvantage of poor heat resistance, making it necessary to develop alternative raw materials.

[0003] Meanwhile, polyester is widely used as a raw material for fibers, films, packaging materials, molded products, construction materials, and interior / exterior materials, as well as for various industrial applications such as display devices, due to its excellent mechanical properties, such as durability and heat resistance, and optical properties, such as transparency. Although polyester is attracting attention as a raw material capable of replacing PVC due to its eco-friendliness and superior mechanical and optical properties compared to PVC, controlling its flexibility or rigidity is not easy. Therefore, research on polyesters capable of effectively controlling flexibility and rigidity is ongoing.

[0004] For example, Korean Published Patent Application No. 2013-0122746 discloses a copolyester resin capable of controlling softness or hardness by attaching a soft segment or a hard segment.

[0005] [Prior Art Literature]

[0006] [Patent Literature]

[0007] (Patent Document 1) Korean Published Patent Application No. 2013-0122746

[0008] Accordingly, the present invention aims to provide a polyester copolymer that is eco-friendly, ensures quality, processability, transparency, and weather resistance, effectively controls softness and / or hardness, and also has excellent elasticity.

[0009] A polyester copolymer according to one embodiment of the present invention comprises a repeating unit A derived from a first dicarboxylic acid component comprising terephthalic acid (TPA) or dimethyl terephthalate (DMT); a repeating unit B derived from a second dicarboxylic acid component comprising dimethylcyclohexanedicarboxylate (DMCD); and a repeating unit C derived from a diol component comprising a C2-C6 alkanediol compound, wherein the repeating unit B is included in an amount of 40 mol% or less based on the total number of repeating units derived from the entire dicarboxylic acid component.

[0010] A polyester copolymer according to one embodiment of the present invention comprises repeating unit A derived from a first dicarboxylic acid component comprising TPA or DMT; repeating unit B derived from a second dicarboxylic acid component comprising DMCD; and repeating unit C derived from a diol component comprising a C2-C6 alkanediol compound, wherein the repeating unit B is included in an amount of 40 mol% or less based on the total number of repeating units derived from the entire dicarboxylic acid component, thereby being environmentally friendly and having excellent physical properties (e.g., mechanical properties such as hardness and elasticity, and / or optical properties such as transparency and UV blocking) and processability.

[0011] In particular, the above polyester copolymer is economical in that it does not necessarily require the addition of additives (e.g., plasticizers) to control rigidity and / or softness as in conventional methods, and has excellent processability in that rigidity and / or softness can be easily controlled.

[0012] The present invention will be described in detail below. Hereinafter, the present invention is not limited to the contents described below, but may be modified in various forms as long as the essence of the invention is not altered.

[0013] In this specification, the use of the term "comprising" is intended to specify certain characteristics, regions, steps, processes, elements, and / or components, and unless specifically stated otherwise, it does not exclude the presence or addition of other characteristics, regions, steps, processes, elements, and / or components.

[0014] All numbers and expressions indicating the amounts of components, reaction conditions, etc. described in this specification may be understood to be modified by the term "about" in all cases unless otherwise specified.

[0015] In this specification, terms such as "first," "second," etc. are used to describe various components, and said components are not limited to said terms. These terms are used for the purpose of distinguishing one component from another.

[0016] In this specification, the term "derivative" may refer to a compound in which the introduction of a functional group, oxidation, reduction, or substitution of atoms is performed on a parent compound, and which is modified to the extent that the structure and properties of the parent compound are not significantly altered.

[0017] In this specification, the term "diol component" may refer to a component comprising a monomer having two or more hydroxyl groups (OH) in its molecule and a polymer having hydroxyl groups (OH) prepared using said monomer. Additionally, the term "dicarboxylic acid component" may refer to a component comprising a monomer having two or more carboxyl groups (COOH) and / or carboxylates (COO) in its molecule and a polymer having carboxyl groups (COOH) and / or carboxylates (COO) prepared using said monomer.

[0018]

[0019] Polyester copolymer

[0020] A polyester copolymer according to one embodiment of the present invention comprises a repeating unit A derived from a first dicarboxylic acid component comprising terephthalic acid (TPA) or dimethyl terephthalate (DMT); a repeating unit B derived from a second dicarboxylic acid component comprising dimethylcyclohexanedicarboxylate (DMCD); and a repeating unit C derived from a diol component comprising a C2-C6 alkanediol compound, wherein the repeating unit B is included in an amount of 40 mol% or less based on the total number of repeating units derived from the entire dicarboxylic acid component.

[0021] The polyester copolymer is formed by (co)polymerizing the first dicarboxylic acid component, the second dicarboxylic acid component, and the diol component, and may be a block copolymer or a random copolymer comprising a repeating unit A (dicarboxylic acid repeating unit A) derived from the first dicarboxylic acid component, a repeating unit B (dicarboxylic acid repeating unit B) derived from the second dicarboxylic acid component, and a repeating unit C (diol repeating unit C) derived from the diol component.

[0022] By including repeating unit A derived from the first dicarboxylic acid component and repeating unit B derived from the second dicarboxylic acid component together, such a polyester copolymer can be environmentally friendly and possess excellent physical properties (e.g., mechanical properties such as rigidity and elasticity, and / or optical properties such as transparency and UV blocking) and processability. In particular, as the content of repeating unit B derived from the second dicarboxylic acid component is controlled within a specific range, the polyester copolymer can exhibit improved productivity and processability while effectively controlling rigidity.

[0023] The first dicarboxylic acid component may include terephthalic acid (TPA), dimethyl terephthalate (DMT), or derivatives thereof. Specifically, the first dicarboxylic acid component may include the terephthalic acid (TPA), dimethyl terephthalate (DMT), or derivatives thereof in an amount of 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 98 mol% or more, or 99 mol% or more (e.g., 80 mol% to 100 mol%, 90 mol% to 100 mol%, or 95 mol% to 99 mol%) based on the total moles of the first dicarboxylic acid component.

[0024] The second dicarboxylic acid component may include dimethyl cyclohexane dicarboxylate (DMCD) or a derivative thereof. Specifically, the second dicarboxylic acid component may be dimethyl 1,4-cyclohexanedicarboxylate. More specifically, the second dicarboxylic acid component may include dimethyl cyclohexane dicarboxylate or a derivative thereof in an amount of 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 98 mol% or more, or 99 mol% or more (e.g., 80 mol% to 100 mol%, 90 mol% to 100 mol%, or 95 mol% to 99 mol%) based on the total moles of the second dicarboxylic acid.

[0025] According to the present invention, the polyester copolymer may comprise repeating unit A derived from the first dicarboxylic acid component in an amount of 60 mol% or more, 65 mol% or more, 70 mol% or more, 72 mol% or more, 80 mol% or more, or 85 mol% or more (e.g., 60 mol% to less than 100 mol%, 65 mol% to 99 mol%, 70 mol% to 95 mol%, 72 mol% to 93 mol%, 76 mol% to 91 mol%, or 80 mol% to 90 mol%) based on the total number of repeating units derived from the total dicarboxylic acid component (e.g., first dicarboxylic acid component + second dicarboxylic acid component).

[0026] In addition, the polyester copolymer may contain repeating unit B derived from the second dicarboxylic acid component in an amount of 40 mol% or less, 35 mol% or less, 30 mol% or less, 28 mol% or less, 20 mol% or less, or 15 mol% or less, based on the total number of repeating units derived from the total dicarboxylic acid component (e.g., first dicarboxylic acid component + second dicarboxylic acid component).

[0027] Meanwhile, the polyester copolymer may further include a repeating unit E derived from a third dicarboxylic acid component. The third dicarboxylic acid component is a dicarboxylic acid component different from the first dicarboxylic acid component and the second dicarboxylic acid component. Specifically, the third dicarboxylic acid component may include one or more selected from the group consisting of succinic acid, adipic acid, sebacic acid, azeraic acid, dodecanoic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, and dibutyl isophthalate.

[0028] The polyester copolymer may contain, based on the total number of moles of repeating units derived from the total dicarboxylic acid components (e.g., first dicarboxylic acid component + second dicarboxylic acid component + third dicarboxylic acid component), repeating unit E derived from the third dicarboxylic acid component in an amount of 30 mole% or less, 25 mole% or less, 15 mole% or less, 10 mole% or less, 5 mole% or less, 3 mole% or less, or 1 mole% or less (e.g., 0 mole% to 30 mole%, more than 0 mole% to 20 mole%, 0.1 mole% to 15 mole%, 0.5 mole% to 10 mole%, 1 mole% to 5 mole%, or 1.5 mole% or 3 mole%).

[0029] Meanwhile, the above diol component (first diol component) may include a C2-C6 alkanediol compound (specifically, a C2-C6 linear alkanediol compound). Specifically, the above diol component may include the C2-C6 alkanediol compound in an amount of 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 98 mol% or more, or 99 mol% or more (e.g., 80 mol% to 100 mol%, 90 mol% to 100 mol%, or 95 mol% to 99 mol%) based on the total moles of the diol component (first diol component).

[0030] Specifically, the above C2-C6 alkanediol compound may include one or more selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethylpropane-1,3-diol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 2,6-hexanediol, and 3,4-hexanediol. For example, when considering the control of the basic physical properties and rigidity of the above polyester copolymer, the above C2-C6 alkanediol compound may be ethylene glycol or 1,4-butanediol.

[0031] According to the present invention, the polyester copolymer may further comprise a repeating unit F derived from a diol component (a second diol component) different from the diol component. Specifically, the diol component (a second diol component) different from the diol component may comprise one or more selected from the group consisting of cyclohexanedimethanol, isosorbide, and diethylene glycol.

[0032] The polyester copolymer may contain repeating unit C derived from the diol component (first diol component) in an amount of 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, 98 mol% or more, or 99 mol% or more (e.g., 80 mol% to 100 mol%, 90 mol% to 100 mol%, or 95 mol% to 99 mol%) based on the total number of repeating units derived from the total diol component (e.g., first diol component + second diol component).

[0033] In addition, the polyester copolymer may contain repeating unit F derived from the diol component (second diol component) in an amount of 30 mol% or less, 25 mol% or less, 15 mol% or less, 10 mol% or less, 5 mol% or less, 3 mol% or less, 2 mol% or less, or 1 mol% or less (e.g., 0 mol% to 20 mol%, 0 mol% to 10 mol%, or 1 mol% to 5 mol%) based on the total number of repeating units derived from the total diol component (e.g., first diol component + second diol component).

[0034] According to the present invention, the polyester copolymer may further comprise repeating unit D derived from a polyester component comprising polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene ether glycol (PTMEG) (e.g., PTMEG 1000, PTMEG 2000). As the polyester copolymer further comprises repeating unit D derived from the polyester component, the flexibility is controlled along with the rigidity, thereby providing a polyester copolymer with improved elasticity.

[0035] The polyester copolymer may contain the repeating unit D in an amount of 10 mol% or less, 7 mol% or less, 5 mol% or less, 3 mol% or less, 2 mol% or less, or 1 mol% or less (e.g., 0 mol% to 10 mol%, more than 0 mol% to 10 mol%, 1 mol% to 6 mol%, or 2 mol% to 4 mol%) based on the total number of repeating units derived from the total diol components (e.g., first diol component + second diol component + polyester component).

[0036] Based on the total number of repeating units included in the polyester copolymer (total number of repeating units constituting the polyester copolymer), the polyester copolymer may contain repeating unit A derived from the first dicarboxylic acid component in an amount of 30 mol% to 50 mol%, repeating unit B derived from the second dicarboxylic acid component in an amount of 1 mol% to 20 mol%, repeating unit C derived from the diol component (first diol component) in an amount of 40 mol% to 50 mol%, and repeating unit D derived from the polyester component in an amount of 0 mol% to 10 mol%.

[0037] According to the present invention, the polyester copolymer may be a copolymer obtained by reacting terephthalic acid (TPA), dimethylcyclohexanedicarboxylate (DMCD), and ethylene glycol (EG). That is, the first dicarboxylic acid component may be terephthalic acid (TPA), the second dicarboxylic acid component may be dimethylcyclohexanedicarboxylate (DMCD), and the diol component (first diol component) may be ethylene glycol, and the polyester copolymer may include repeating units derived from each of these components.

[0038] Additionally, the polyester copolymer may be a copolymer obtained by reacting dimethyl terephthalate (DMT), dimethylcyclohexanedicarboxylate (DMCD), and 1,4-butanediol (1,4-BD). That is, the first dicarboxylic acid component may be dimethyl terephthalate (DMT), the second dicarboxylic acid component may be dimethylcyclohexanedicarboxylate (DMCD), and the diol component (first diol component) may be 1,4-butanediol, and the polyester copolymer may include repeating units derived from each of these components.

[0039] Additionally, the polyester copolymer may be a copolymer obtained by reacting dimethyl terephthalate (DMT), dimethylcyclohexanedicarboxylate (DMCD), 1,4-butanediol (1,4-BD), and polytetramethylene ether glycol (PTMEG). That is, the first dicarboxylic acid component may be dimethyl terephthalate (DMT), the second dicarboxylic acid component may be dimethylcyclohexanedicarboxylate (DMCD), the diol component (first diol component) may be 1,4-butanediol, and the polyester component may be polytetramethylene ether glycol (PTMEG), and the polyester copolymer may include repeating units derived from each of these components.

[0040] According to the present invention, the polyester copolymer may have a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of -35 ℃ to 80 ℃. Specifically, the glass transition temperature (Tg) of the polyester copolymer may be -30 ℃ to 78 ℃, -25 ℃ to 75 ℃, -20 ℃ to 70 ℃, -15 ℃ to 60 ℃, -10 ℃ to 50 ℃, 0 ℃ to 30 ℃, 5 ℃ to 20 ℃, 10 ℃ to 80 ℃, 20 ℃ to 77 ℃, 30 ℃ to 75 ℃, 40 ℃ to 70 ℃, or 50 ℃ to 70 ℃. By satisfying the above ranges for the glass transition temperature (Tg), a polyester copolymer with improved heat resistance can be provided.

[0041] In addition, the polyester copolymer may have a crystallization temperature (Tc) measured by differential scanning calorimetry (DSC) of 5°C to 175°C. Specifically, the crystallization temperature (Tc) of the polyester copolymer may be 7°C to 173°C, 7°C to 170°C, 10°C to 120°C, 10°C to 70°C, 30°C to 175°C, 50°C to 171°C, 100°C to 170°C, or 145°C to 165°C.

[0042] Additionally, the polyester copolymer may have a melting temperature (Tm) measured by differential scanning calorimetry (DSC) of 140 ℃ to 250 ℃. Specifically, the melting temperature (Tm) of the polyester copolymer may be 145 ℃ to 248 ℃, 150 ℃ to 245 ℃, 155 ℃ to 190 ℃, 160 ℃ to 240 ℃, 170 ℃ to 220 ℃, 180 ℃ to 210 ℃, or 190 ℃ to 245 ℃.

[0043] According to the present invention, the polyester copolymer may have a weight-average molecular weight of 70,000 g / mol to 160,000 g / mol. Specifically, the weight-average molecular weight of the polyester copolymer may be 65,000 g / mol to 155,000 g / mol, 60,000 g / mol to 150,000 g / mol, or 55,000 g / mol to 140,000 g / mol.

[0044] The above polyester copolymer may have an intrinsic viscosity (IV) of 0.6 dl / g to 1.5 dl / g. Specifically, the intrinsic viscosity (IV) of the above polyester copolymer may be 0.65 dl / g to 1.5 dl / g, 0.68 dl / g to 1.4 dl / g, 0.7 dl / g to 1.3 dl / g, 0.72 dl / g to 1.2 dl / g, or 0.74 dl / g to 1.1 dl / g.

[0045] The polyester copolymer may have a specific gravity of 1.1 to 1.4 and a Shore D hardness of 30 to 95. Specifically, the specific gravity of the polyester copolymer may be 1.12 to 1.4, 1.15 to 1.4, or 1.2 to 1.4. Additionally, the Shore D hardness of the polyester copolymer may be 35 to 90, 40 to 85, or 45 to 80.

[0046] The polyester copolymer may have a tensile strength of 25 MPa to 65 MPa and a tensile elongation of 100% to 1,200%. Specifically, the tensile strength of the polyester copolymer may be 30 MPa to 60 MPa, 35 MPa to 55 MPa, 38 MPa to 50 MPa, or 40 MPa to 50 MPa. Additionally, the tensile elongation of the polyester copolymer may be 200% to 1,150%, 230% to 1,000%, 250% to 700%, or 260% to 500%.

[0047] The polyester copolymer may have a flexural strength of 5 MPa to 90 MPa and a flexural modulus of 80 MPa to 2,700 MPa. Specifically, the flexural strength of the polyester copolymer may be 5 MPa to 89 MPa, 10 MPa to 88 MPa, 30 MPa to 87 MPa, 35 MPa to 85 MPa, 5 MPa to 40 MPa, or 80 MPa to 85 MPa. The bending modulus of the above polyester copolymer may be 85 MPa to 2,650 MPa, 90 MPa to 1,000 MPa, 91 MPa to 500 MPa, 1,000 MPa to 2,600 MPa, 1,500 MPa to 2,550 MPa, or 2,000 MPa to 2,500 MPa.

[0048]

[0049] Method for manufacturing a polyester copolymer

[0050] A method for preparing a polyester copolymer according to another embodiment of the present invention comprises the steps of: mixing a first dicarboxylic acid component comprising terephthalic acid (TPA), dimethyl terephthalate (DMT) or a derivative thereof, a second dicarboxylic acid component comprising dimethylcyclohexanedicarboxylate (DMCD) or a derivative thereof, and a diol component comprising a C2-C6 alkanediol compound; obtaining a product by performing an esterification reaction or an ester exchange reaction on the mixture obtained through the mixing; and performing a polycondensation reaction on the product.

[0051] The polyester copolymer produced according to the method for producing the above polyester copolymer has substantially the same composition and characteristics as the aforementioned polyester copolymer.

[0052] The method for manufacturing the above polyester copolymer involves controlling the raw material composition and process conditions to obtain a polyester copolymer in which mechanical properties such as rigidity and elasticity, optical properties such as transparency and UV blocking, and processability are controlled to the desired level. This is explained in detail as follows.

[0053]

[0054] First, the first dicarboxylic acid component, the second dicarboxylic acid component, and the diol component (the first diol component) are mixed.

[0055] The description of the first dicarboxylic acid component, the second dicarboxylic acid component, and the diol component (first diol component) is as described above.

[0056] According to the present invention, one or more additives selected from the group consisting of catalysts, colorants, crystallizing agents, oxidation stabilizers, stabilizers, and branching agents may be additionally added to the mixture of the first dicarboxylic acid component, the second dicarboxylic acid component, and the diol component.

[0057] The catalyst may be a methylate of sodium, magnesium, etc.; an acetate, borate, fatty acid salt, or carbonate of Ge, Zn, Cd, Mn, Co, Ca, Ba, etc.; or an oxide or hydrate of Ge, Mg, Pb, Mn, Ti, Sb, Sn, Al, etc. Specifically, the catalyst may be tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, 2-ethylhexyl titanate, octylene glycol titanate, triethanolamine titanate, ethyl acetoacetic ester titanate, isostearyl titanate, titanium dioxide, germanium dioxide, germanium tetrachloride, germanium ethylene glycoside, germanium acetate, or a combination thereof.

[0058] The above-mentioned colorant is an additive for improving the color characteristics of the polyester copolymer. As the above-mentioned colorant, cobalt-based compounds (e.g., cobalt acetate, cobalt propionate), anthraquinone-based compounds, perinone-based compounds, azo-based compounds, methine-based compounds, etc. may be used, and commercially available products include Clariant’s Polysynthren Blue RLS and Clariant’s Solvaperm Red BB.

[0059] The polyester copolymer may contain the colorant in an amount of 0.1 ppm to 30 ppm based on the total weight of the polyester copolymer. Specifically, the content of the colorant may be 0.2 ppm to 30 ppm, 0.5 ppm to 25 ppm, 0.6 ppm to 23 ppm, or 0.8 ppm to 20 ppm based on the total weight of the polyester copolymer. By satisfying the above ranges for the content of the colorant, color characteristics can be sufficiently improved without deteriorating the mechanical properties of the polyester copolymer.

[0060] As the crystallizing agent, commonly known crystallization nucleating agents, ultraviolet absorbers, polyolefin resins, polyamide resins, or polyalkylene resins may be used.

[0061] The polyester copolymer may contain the crystallizing agent in an amount of 0.1 ppm to 10 ppm based on the total weight of the polyester copolymer. Specifically, the content of the crystallizing agent may be 0.2 ppm to 8 ppm, 0.5 ppm to 6 ppm, 1 ppm to 10 ppm, 2 ppm to 8 ppm, 3 ppm to 6 ppm, or 4 ppm to 6 ppm based on the total weight of the polyester copolymer. By satisfying the above ranges for the content of the crystallizing agent, the heat resistance and impact strength of the polyester copolymer can be improved.

[0062] As the above oxidation stabilizer, commonly known hindered phenol-based oxidation stabilizers, phosphite-based oxidation stabilizers, or thioether-based oxidation stabilizers may be used.

[0063] The above polyester copolymer may contain the oxidation stabilizer in an amount of 50 ppm to 2,500 ppm based on the total weight of the polyester copolymer. Specifically, the content of the oxidation stabilizer may be 50 ppm to 2,300 ppm, 60 ppm to 2,200 ppm, 80 ppm to 2,100 ppm, 100 ppm to 2,000 ppm, or 100 ppm to 1,500 ppm based on the total weight of the polyester copolymer. By satisfying the above range for the content of the oxidation stabilizer, it is possible to effectively prevent a decrease in intrinsic viscosity that may occur during processes such as post-processing, while also preventing a decrease in physical properties such as impact strength.

[0064] Phosphorus-based compounds such as phosphoric acid, trimethylphosphate, and triethylphosphate can be used as the above-mentioned stabilizer.

[0065] The polyester copolymer may contain the stabilizer in an amount of 10 ppm to 2,500 ppm based on the total weight of the polyester copolymer. Specifically, the content of the stabilizer may be 150 ppm to 2,300 ppm, 200 ppm to 2,000 ppm, 300 ppm to 1,500 ppm, 50 ppm to 400 ppm, 70 ppm to 350 ppm, or 100 ppm to 300 ppm based on the total weight of the polyester copolymer.

[0066] Trimellitic anhydride, trimethylol propane, or trimellitic acid may be used as the above branching agent.

[0067] The above polyester copolymer may contain the branching agent in an amount of 100 ppm to 2,500 ppm based on the total weight of the polyester copolymer. Specifically, the content of the branching agent may be 200 ppm to 2,500 ppm, 300 ppm to 2,300 ppm, 500 ppm to 2,300 ppm, 1,000 ppm to 2,500 ppm, 1,500 ppm to 2,300 ppm, or 1,800 ppm to 2,100 ppm based on the total weight of the polyester copolymer. By satisfying the above ranges for the content of the branching agent, the intrinsic viscosity can be controlled more efficiently, thereby improving physical properties such as the impact strength of the polyester copolymer.

[0068]

[0069] Next, the mixture obtained through the above mixing is subjected to an esterification reaction or an ester exchange reaction.

[0070] The above esterification reaction, or transesterification reaction, is carried out at atmospheric pressure, or 0.1 kg / cm² relative to atmospheric pressure. 2 up to 3.0 kg / cm² 2It can be performed for 2 to 12 hours at a pressure in a pressurized state as high as that and a temperature of 180 ℃ to 275 ℃. The pressurized state is 0.2 kg / cm² relative to atmospheric pressure. 2 up to 2.5 kg / cm² 2 , 0.3 kg / cm 2 Up to 2.2 kg / cm² 2 , 0.5 kg / cm 2 Up to 2.0 kg / cm² 2 or 1.0 kg / cm² 2 Up to 2.0 kg / cm² 2 It can be as high as that.

[0071] Specifically, the esterification reaction may be performed at a temperature of 185°C to 270°C, 190°C to 260°C, 190°C to 250°C, or 195°C to 240°C for 3 to 11 hours, 3 to 10 hours, 4 to 8 hours, or 5 to 6 hours. Additionally, the ester exchange reaction may be performed at a temperature of 150°C to 250°C, 160°C to 240°C, 170°C to 230°C, or 180°C to 220°C for 2 to 10 hours, 2 to 8 hours, 2 to 6 hours, or 3 to 4 hours.

[0072] When the above esterification reaction or the above ester exchange reaction is completed, the pressure of the reactor is adjusted, and the product is transferred to a reactor for a polycondensation reaction to perform the following polycondensation reaction.

[0073]

[0074] Next, the above product is subjected to a polycondensation reaction.

[0075] The above polycondensation reaction can be carried out for 1 to 10 hours at a pressure of 0.01 mmHg to 400 mmHg and a temperature of 220 ℃ to 290 ℃. Specifically, the polycondensation reaction may be carried out for 1 to 8 hours or 2 to 6 hours at a pressure of 0.01 mmHg to 200 mmHg, 0.05 mmHg to 100 mmHg, 0.1 mmHg to 50 mmHg, 0.2 mmHg to 10 mmHg, 0.2 mmHg to 3 mmHg, 0.3 mmHg to 1.5 mmHg, or 0.5 mmHg to 1.2 mmHg and a temperature of 225 ℃ to 285 ℃, 230 ℃ to 280 ℃, 230 ℃ to 250 ℃, 255 ℃ to 285 ℃, or 250 ℃ to 280 ℃.

[0076] In the initial stage of the above polycondensation reaction, the stirring speed is set to be fast, and as the polycondensation reaction proceeds, if the stirring force weakens due to an increase in the viscosity of the reaction product or if the temperature of the reaction product rises above the set temperature, the stirring speed can be appropriately adjusted accordingly.

[0077] In addition, additives introduced during the esterification reaction or ester exchange reaction (e.g., catalyst, colorant, crystallizing agent, oxidation stabilizer, stabilizer, branching agent) may be additionally introduced into the above polycondensation reaction.

[0078] This polycondensation reaction can proceed until the intrinsic viscosity (IV) of the reaction product reaches 0.6 dl / g to 1.5 dl / g, 0.65 dl / g to 1.5 dl / g, 0.68 dl / g to 1.4 dl / g, 0.7 dl / g to 1.3 dl / g, 0.72 dl / g to 1.2 dl / g, or 0.74 dl / g to 1.1 dl / g.

[0079]

[0080] The above contents will be explained in more detail by the following examples. However, the following examples are merely for illustrating the present invention, and the scope of the examples is not limited to these.

[0081]

[0082] [Example]

[0083] Preparation of polyester copolymer

[0084] Example 1

[0085] (1) Esterification reaction

[0086] 2,072 g of terephthalic acid (TPA), 104 g of dimethylcyclohexanedicarboxylate (DMCD), and 1,612 g of ethylene glycol (EG) were added to a 10 L reactor connected to a column and a condenser capable of cooling with water. Next, 1.8 g of tetrabutyl titanate (TBT) as a catalyst, 0.235 g of phosphoric acid as a stabilizer, and 1.47 g of trimellitic anhydride as a branching agent were added and stirred.

[0087] Next, nitrogen is injected into the reactor to reduce the reactor pressure to 1.0 kgf / cm² relative to atmospheric pressure. 2The reactor was subjected to a high pressure (absolute pressure: 1495.6 mmHg). Subsequently, the temperature of the reactor was raised from room temperature to 220°C over 90 minutes, maintained at 220°C for 2 hours, and then raised again to 260°C over 2 hours. Afterward, the esterification reaction was carried out at 260°C for 3 hours while visually observing the composition inside the reactor until it became transparent. During this process, byproducts were discharged through a column and a condenser. Once the esterification reaction was completed, the nitrogen inside the pressurized reactor was purged to lower the pressure to atmospheric pressure, and the product inside the reactor was transferred to a 7L capacity reactor capable of vacuum reaction.

[0088] (2) Polycondensation reaction

[0089] The pressure of the reactor into which the product obtained through the above esterification reaction was introduced was reduced from atmospheric pressure to 5.0 Torr (absolute pressure: 5 mmHg) over 30 minutes, and at the same time, the temperature of the reactor was increased to 275 ℃ over 1 hour, and then the polycondensation reaction was carried out while maintaining the pressure of the reactor at 1.0 Torr (absolute pressure: 1.0 mmHg) or lower. The polycondensation reaction was carried out while appropriately adjusting the stirring speed until the intrinsic viscosity (IV) of the reaction product (molten material) inside the reactor reached 0.77 dl / g, after which the reaction product was discharged outside the reactor and formed into a strand, and then solidified with a cooling liquid and granulated to an average weight of about 12 mg to 14 mg to produce a polyester copolymer.

[0090]

[0091] Examples 2 to 7

[0092] A polyester copolymer was prepared in the same manner as in Example 1, except that the raw material components and their content were applied as shown in Table 1 below, and the conditions of the esterification reaction (or ester exchange reaction) and polycondensation reaction were adjusted according to the raw material components.

[0093] Classification Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 TPA(g)1,718 1,938 2,027 2,072---DMT(g)----1,530 1,228 1,621DMCD(g)518 260 156 1046 765 434 18EG(g)1,604 1,609 1,611 1,612---1,4-BD(g)----1,370 1,051 1,250PTMEG 1000(g)-----542209 Catalyst(g)1.8 1.8 1.8 1.8 1.8 1.8 1.8 Stabilizer(g)0.235 0.235 0.235 0.235 0.235 0.235 0.235 0.235 0.235 0.235 0.235 Activating agent(g)1.47 1.47 1.47 1.47 1.47 1.47 1.47 1.47

[0094]

[0095] Comparative Example 1

[0096] Polyethylene terephthalate (PET, SB grade) from Huvis Co., Ltd. was prepared.

[0097]

[0098] Comparative Example 2

[0099] Glycol-modified polyethylene terephthalate (PETG, K2012) from SK Chemicals Co., Ltd. was prepared.

[0100]

[0101] [Experimental Example]

[0102] Experimental Example 1: Composition of polyester copolymer, PET, and PETG

[0103] After dissolving the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 in a CDCl3 solvent at a concentration of 3 mg / mL, the results obtained at 25 °C using a nuclear magnetic resonance device (JEOL, 600 MHz FT-NMR) 1The composition (mol% of repeating units) of the polyester copolymer, PET, and PETG was confirmed through H-NMR spectra.

[0104]

[0105] Experimental Example 2: Intrinsic Viscosity

[0106] The polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 were each dissolved in orthochlorophenol (OCP) at 150 °C at a concentration of 0.12%, and then the intrinsic viscosity (IV, dl / g) was measured using a Ubelrod type viscometer in a constant temperature bath at 35 °C.

[0107]

[0108] Experimental Example 3: Tg, Tc, and Tm

[0109] For the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2, the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) were measured using a differential scanning calorimeter (DSC). Specifically, a first scan was obtained by increasing the temperature from -70 ℃ to 260 ℃ at a rate of 10 ℃ / min and maintaining it at 260 ℃ for 5 minutes using a differential scanning calorimeter, decreasing the temperature from 260 ℃ to -70 ℃ at a rate of -300 ℃ / min and maintaining it for 5 minutes, and then increasing the temperature again from -70 ℃ to 260 ℃ at a rate of 10 ℃ / min to obtain a second scan. The glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) were analyzed from the heat flow curves obtained during the above process.

[0110]

[0111] Experimental Example 4: Specific Gravity

[0112] The specific gravity of the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 was measured according to ASTM D256.

[0113]

[0114] Experimental Example 5: Shore D Hardness

[0115] The Shore D hardness of the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 was measured according to ASTM D2240-05.

[0116]

[0117] Experimental Example 6: Tensile Strength and Tensile Elongation

[0118] According to ASTM D638, the tensile strength and tensile elongation of the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 were measured. Specifically, the polyester copolymer, PET, and PETG were each processed using an injection molding machine at a temperature of 240°C to 270°C to obtain flat injection molded products with a thickness of 6 mm, and then the obtained injection molded products were cut to a length of 100 mm and a width of 15 mm to prepare specimens. Next, the specimens were mounted using an INSTRON universal testing machine (4206-001) with a chuck spacing of 50 mm, and the test was conducted at a tensile speed of 500 mm / min. Then, the tensile strength at which the specimens fractured was measured using a program embedded in the equipment. In addition, the maximum deformation just before fracture was measured at a speed of 500 mm / min, and the tensile elongation was measured by calculating the ratio of the maximum deformation to the initial length of the specimen.

[0119]

[0120] Experimental Example 7: Flexural Strength and Flexural Modulus

[0121] The flexural strength and flexural modulus of the polyester copolymers of Examples 1 to 7, the PET of Comparative Example 1, and the PETG of Comparative Example 2 were measured according to ASTM D790. Specifically, the polyester copolymer, PET, and PETG were each processed using an injection molding machine at a temperature of 240°C to 270°C to obtain flat injection molded articles with a thickness of 6 mm, and then the obtained injection molded articles were cut to a length of 100 mm and a width of 15 mm to prepare specimens. Next, the flexural strength and flexural modulus of the specimens were measured under three-point bending strength conditions using an INSTRON universal testing machine (4206-001).

[0122] Classification Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 DMCD Derived Repeating Unit B (Moll%) 20 10 64 30 30 20-- Intrinsic Viscosity (IV, dl / g) 0.77 0.74 0.77 0.77 1.01 01 00.8 0.67 Tg (°C) 68 68 76 77 16 -33 15 75 80 Tc (°C) 17 0 17 11 50 15 14 31 0 49 130- Tm (°C) 21 7 21 42 40 24 31 70 15 5 18 52 60- Specific Gravity 1.3 1 1.3 21.3 21.3 31.26 1.19 1.25 1.3 31.27 Shore D Hardness 80 80 80 80 68 48 61 80 80 Tensile Strength (@break, MPa) 43 42 40 26 40 48 46 43 30 Tensile Elongation (@break, %) 45 0 42 0 26 0 29 0 42 0 1,100 58 0 45 250 Flexural Strength (MPa) 83 8 48 58 53 55 18 83 75 Flexural Modulus (MPa) 2,4 20 2,4 90 2,5 00 2,4 90 90 0 92 33 0 2,4 60 2,200

[0123]

[0124] As shown in Table 2 above, the polyester copolymers of Examples 1 to 7 according to the present invention are environmentally friendly and have mechanical properties similar to those of PET of Comparative Example 1 and PETG of Comparative Example 2 that were used conventionally, and it can be confirmed that the intrinsic viscosity, glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) also satisfy desirable ranges.

[0125] Specifically, it can be seen that the polyester copolymers of Examples 1 to 4 have excellent mechanical properties such as hardness, as the hardness is controlled by having a content of repeating unit B derived from DMCD of 40 mol% or less. In addition, it can be seen that the polyester copolymer of Example 5 has excellent mechanical properties such as hardness and elasticity, as 1,4-BD, which can impart softness, is used while having a content of repeating unit B derived from DMCD of 40 mol% or less. Furthermore, it can be seen that the polyester copolymers of Examples 6 and 7 also have excellent mechanical properties such as hardness and elasticity, as 1,4-BD and PTMEG, which can impart softness, are used while having a content of repeating unit B derived from DMCD of 40 mol% or less.

Claims

1. Repeating unit A derived from a first dicarboxylic acid component comprising terephthalic acid (TPA) or dimethyl terephthalate (DMT); Repeating unit B derived from a second dicarboxylic acid component comprising dimethylcyclohexanedicarboxylate (DMCD); and It comprises a repeating unit C derived from a diol component containing a C2-C6 alkanediol compound, and A polyester copolymer comprising 40 mol% or less of the repeating unit B based on the total molar amount of repeating units derived from the entire dicarboxylic acid component.

2. In Paragraph 1, A polyester copolymer comprising 30 mol% or less of the repeating unit B based on the total molar amount of repeating units derived from the entire dicarboxylic acid component.

3. In Paragraph 1, A polyester copolymer comprising one or more C2-C6 alkanediol compounds selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethylpropane-1,3-diol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 2,6-hexanediol, and 3,4-hexanediol.

4. In Paragraph 1, A polyester copolymer further comprising a repeating unit D derived from a polyester component comprising polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene ether glycol (PTMEG).

5. In Paragraph 4, A polyester copolymer comprising more than 0 mol% to 10 mol% of repeating unit D, based on the total molar amount of repeating units derived from the entire diol component.

6. In Paragraph 1, The above first dicarboxylic acid component is the above terephthalic acid (TPA), and The above second dicarboxylic acid component is the above dimethylcyclohexanedicarboxylate (DMCD), and Polyester copolymer in which the above diol component is ethylene glycol.

7. In Paragraph 1, The above first dicarboxylic acid component is the above dimethyl terephthalate (DMT), and The above second dicarboxylic acid component is the above dimethylcyclohexanedicarboxylate (DMCD), and Polyester copolymer in which the above diol component is 1,4-butanediol.

8. In Paragraph 1, Polyester copolymer that is a block copolymer or a random copolymer.

9. In Paragraph 1, A polyester copolymer having a glass transition temperature (Tg) of -35 °C to 80 °C as measured by differential scanning calorimetry (DSC), a crystallization temperature (Tc) of 5 °C to 175 °C, and a melting temperature (Tm) of 140 °C to 250 °C.

10. In Paragraph 1, A polyester copolymer having a weight-average molecular weight of 70,000 g / mol to 160,000 g / mol and an intrinsic viscosity (IV) of 0.6 dl / g to 1.5 dl / g.

11. In Paragraph 1, Polyester copolymer having a specific gravity of 1.1 to 1.4 and a Shore D hardness of 30 to 95.

12. In Paragraph 1, A polyester copolymer having a tensile strength of 25 MPa to 65 MPa and a tensile elongation of 100% to 1,200%.

13. In Paragraph 1, A polyester copolymer having a flexural strength of 5 MPa to 90 MPa and a flexural modulus of 80 MPa to 2,700 MPa.