Polyester resin

Abstract

The purpose of the present invention is to provide a polyester resin that exhibits excellent gelling suppression, moldability, surface smoothness, transparency, mechanical characteristics and heat resistance.　The present invention relates to a polyester resin characterized by containing a dicarboxylic acid component and an alcohol component as polyester constituent components, with the content of a compound represented by formula (II) being 0.0002-5.9 wt% relative to 100 wt% of the alcohol component. (In the formula, m and n are each 1-1000, l is 0-1000, R1 denotes an aromatic hydrocarbon group having 6-20 carbon atoms, and R2, R3 and R4 each denote a hydrogen atom or an alkyl group having 1-10 carbon atoms.)

Description

[Technical Field]

[0001] This invention relates to a polyester resin that provides molded articles with excellent moldability, transparency, mechanical properties, and heat resistance. More specifically, this invention relates to a polyester resin that improves moldability in extrusion molding, shape extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, which require high melt tension, as well as improving transparency, heat resistance, mechanical properties, and heat resistance. [Background technology]

[0002] In recent years, there has been a trend to replace polyvinyl chloride resins with other materials, for example, due to environmental impact issues. Among the many alternative materials, polyester resin is being considered as a promising material in terms of physical properties, environmental suitability, adhesive properties, and price.

[0003] In particular, crystalline polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) are used in a variety of melt-molded products, including heat-resistant parts produced by injection molding, films and sheets produced by extrusion molding, beverage bottles produced by blow molding, and fibers produced by melt spinning.

[0004] However, improving the transparency and flexibility of molded products using these crystalline polyester resins requires various technologies, such as controlling cooling conditions during processing and stretching treatments. Furthermore, in shape extrusion molding, direct blow molding, and inflation molding, which require high melt tension, the drawdown phenomenon becomes significant, causing pre-molded or molded products to sag, resulting in uneven thickness and increased burrs in the molded products, which leads to problems such as a decrease in the yield rate and stability of continuous production.

[0005] On the other hand, in order to solve the problem of such a drawdown phenomenon, an invention is disclosed that improves the moldability of direct blow molding, which requires high melt tension, by introducing a branched structure (branching agent) into the resin skeleton (for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the technologies of Patent Documents 1 to 3, the reactivity between the branched structures (branching agents) is high, and even when they are mixed with a carboxylic acid compound and reacted with the components of the polyester resin, gelation products are generated, the solubility with the components of the polyester resin decreases, and there is a problem that the obtained polyester resin molded product cannot provide good surface smoothness. In addition, in Patent Documents 1 to 3, although the drawdown phenomenon is improved, due to the too high melt tension, when the resin is discharged from the die during molding, the surface smoothness of the molded product is reduced due to the occurrence of melt fracture, and there is also a problem that the transparency of the molded product decreases. In addition, the molded product of the polyester resin is also required to have heat resistance and the like. Furthermore, in the manufacturing process of the polyester resin, cyclic oligomers (including tetramers) are generated, and the problem is that the continuous moldability decreases because this cyclic oligomer contaminates the mold during processing.

[0008] This invention was made against the backdrop of the problems of the prior art, and its objective is to provide a polyester resin that yields molded articles with excellent gelation suppression, moldability, surface smoothness, transparency, mechanical properties, and heat resistance. Furthermore, an essential problem to be addressed by this invention is to provide a polyester resin with a low cyclic oligomer content that yields molded articles with excellent continuous moldability.

[0009] More specifically, the object of the present invention is to provide a polyester resin that offers excellent moldability in extrusion molding, morph extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, which require high melt tension, and provides moldable articles with superior properties. [Means for solving the problem]

[0010] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by the means described below, and have arrived at the present invention. That is, the present invention has the following configuration.

[0011] [1] A polyester resin characterized by containing a dicarboxylic acid component and an alcohol component as constituent components of the polyester, wherein the content of the compound represented by formula (II) is 0.0002 to 5.9% by weight of 100% by weight of the alcohol component. [ka] (In the formula, m and n represent 1 to 1000, and l represents 0 to 1000, R 1 This represents an aromatic hydrocarbon group with 6 to 20 carbon atoms, R 2 , R 3 , R 4 Each of these represents either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. [2] The polyester resin according to [1], wherein the weight-average molecular weight of the compound represented by formula (II) is 250 or more and 500,000 or less. [3] A polyester resin according to [1] or [2], comprising terephthalic acid in an amount of 85 to 100 mol% of the dicarboxylic acid component and ethylene glycol as an alcohol component. [4] The polyester resin according to any one of [1] to [3], wherein the content of cyclic oligomer tetramers in the polyester resin is less than 2680 ppm. [5] Melt tension was measured at a temperature of 270°C, a draw speed of 100 m / min, and a shear speed of 243 s. -1 And a polyester resin as described in any of [1] to [4], having a N of 15 mN or more. [6] Melt viscosity at a temperature of 270°C and a shear rate of 30s -1 Therefore, the pressure is 26,000 dPa·s or higher, the temperature is 270°C, and the shear rate is 2000 s. -1 The polyester resin described in any of [1] to [5], wherein the pressure is 6500 dPa·s or less. [Effects of the Invention]

[0012] According to the present invention, a molded article of polyester resin with excellent gelation suppression, moldability, surface smoothness, transparency, mechanical properties, and heat resistance can be obtained. In particular, its moldability is superior to conventional methods in extrusion molding, shape extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering, which require high melt tension. Furthermore, an optional effect of the present invention is the ability to obtain molded articles of polyester resin with a low cyclic oligomer content and excellent continuous moldability. [Modes for carrying out the invention]

[0013] 1. Polyester resin The polyester resin of the present invention is characterized in that it contains a dicarboxylic acid component and an alcohol component (preferably a polyol component) as constituent components of the polyester, and the content of the compound represented by formula (II) is 0.0002 to 5.9% by weight per 100% by weight of the alcohol component.

[0014] [ka] (wherein, m and n each represent 1 to 1000, l represents 0 to 1000, and R 1 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R 2 , R 3 , R 4 each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.)

[0015] The polyester resin of the present invention contains a polymer of a predetermined dicarboxylic acid component and an alcohol component, and is characterized in that the content of the compound represented by the formula (II) as the alcohol component is a predetermined amount. In the present invention, the compound represented by the formula (II) is a branching agent for the polyester resin and is used as an alcohol component together with a commonly used diol component (hereinafter simply referred to as the diol component). As long as it binds to the polyester resin chain at an appropriate stage, the compound represented by the formula (II) may exist as a compound in the resin composition, but it is preferable that the compound of the formula (II) exists in a state of being bound to the carboxylic acid component of the polyester resin. The compound represented by the formula (II) has an average of 2 or more (preferably 3 or more) functional groups (hydroxyl groups) capable of reacting with the carboxyl group of the dicarboxylic acid component per molecule in the molecule, and can partially introduce a branched structure into the entire polyester resin.

[0016] On the other hand, the branching agents disclosed in Patent Documents 1 to 3 have an epoxy group and have a high reactivity with the dicarboxylic acid component. Therefore, they react with the dicarboxylic acid component preferentially over the diol component commonly used in polyester resins, and the reaction product can then react with the diol component to form a polyester resin having a hydroxyl group in the side chain. However, during the formation of the polyester resin, the epoxy groups contained in the branching agent may react with each other, and further, the epoxy group may react with the carboxyl group or hydroxyl group of the polyester resin to form a gelled product. The polyester resin of the present invention is formed by the reaction of a compound represented by the formula (II), which is a branching agent having no epoxy group, and a dicarboxylic acid component.

[0017] Thus, the polyester resin of the present invention differs from the polyester resins of Patent Documents 1 to 3 in terms of its resin structure. Since the epoxy groups of the branching agent do not react with each other, and furthermore, the epoxy groups do not react with the carboxyl groups or hydroxyl groups of the polyester resin, gelation can be suppressed. Furthermore, because the polyester resin of the present invention uses a compound represented by formula (II), the melt tension decreases as the temperature increases during melt extrusion, and the melt viscosity decreases under high shear. As a result, melt fracture does not occur during molding, and the resin exhibits excellent moldability, surface smoothness, transparency, mechanical properties, and heat resistance. Furthermore, because polyester resins have a low cyclic oligomer content, mold contamination during processing is reduced, improving continuous molding performance.

[0018] The compounds represented by formula (II) are as follows: [ka]

[0019] (In the formula, m and n represent 1 to 1000, and l represents 0 to 1000, R 1 This represents an aromatic hydrocarbon group with 6 to 20 carbon atoms, R 2 , R 3 , R 4 Each of these represents either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0020] R 1 This represents an aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0021] R 1Aromatic hydrocarbon groups with 6 to 20 carbon atoms represented by include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2-ethylphenyl group, 3-ethylphenyl group, 4-ethylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 4-vinylphenyl group, o-isopropylphenyl group, m-isopropylphenyl group, p-isopropylphenyl group, o-tert-butylphenyl group, m-tert-butylphenyl group, p-tert-butylphenyl Examples include the 3,5-di(tert-butyl)phenyl group, 3,5-di(tert-butyl)-4-methylphenyl group, 4-butylphenyl group, 4-pentylphenyl group, 2,6-bis(1-methylethyl)phenyl group, 2,4,6-tris(1-methylethyl)phenyl group, 4-cyclohexylphenyl group, 2,4,6-trimethylphenyl group, 4-octylphenyl group, 4-(1,1,3,3-tetramethylbutyl)phenyl group, 1-naphthyl group, 2-naphthyl group, 5,6,7,8-tetrahydro-1-naphthyl group, 5,6,7,8-tetrahydro-2-naphthyl group, and fluorenyl group.

[0022] The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 18, more preferably 6 to 15, and even more preferably 6 to 12.

[0023] In particular, the aromatic hydrocarbon group is preferably a phenyl group, an o-tolyl group, an m-tolyl group, or a p-tolyl group, and most preferably a phenyl group.

[0024] R 2 , R 3 , R 4 This represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0025] R 2 , R 3 , R 4The alkyl groups having 1 to 10 carbon atoms represented by this symbol include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; Isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-ethylbutyl group, 3,3-dimethylbutyl group, 1,1,3,3-tetramethylbutyl group, 1-methylbutyl group, 1-ethylpropyl group, 3-methylbutyl group, neopentyl group, 1,1-dimethylpropyl group, 2-methylpentyl group, 3-ethylpentyl group, 1,3-dimethylbutyl group, 2-propylpentyl group, 1-ethyl-1,2-dimethylpropyl group, 1-methylpentyl group, 4-methylpentyl group, 4-methylpentyl group Branched alkyl groups such as hexyl group, 5-methylhexyl group, 2-ethylhexyl group, 1-methylhexyl group, 1-ethylpentyl group, 1-propylbutyl group, 3-ethylheptyl group, 2,2-dimethylheptyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group, 1-butylpentyl group, 1-methylnonyl group, 1-ethyloctyl group, 1-propylheptyl group, and 1-butylhexyl group; Cyclopropyl group, 1-methylcyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, 1-methylcyclohexyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 1,2-dimethylcyclohexyl group, 1,3-dimethylcyclohexyl group, 1,4-dimethylcyclohexyl group, 2,3-dimethylcyclohexyl group, 2,4-dimethylcyclohexyl group, 2,5-dimethylcyclohexyl group Examples of cycloalkyl groups include cyclohydroxyl groups such as 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3,5-dimethylcyclohexyl, 2,2-dimethylcyclohexyl, 3,3-dimethylcyclohexyl, 4,4-dimethylcyclohexyl, cyclooctyl, 2,4,6-trimethylcyclohexyl, 2,2,6,6-tetramethylcyclohexyl, and 3,3,5,5-tetramethylcyclohexyl.

[0026] The number of carbon atoms in the alkyl group is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 4.

[0027] Among these, the alkyl group is particularly preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and most preferably a methyl group.

[0028] R 2 and R 3 It is preferably an alkyl group having 1 to 10 carbon atoms, R 4 It is preferable that it is a hydrogen atom.

[0029] The aforementioned l, m, and n are the ratios of the copolymer components (L), (M), and (N) contained in one molecule, and the average number of each component contained in one molecule, expressed as an integer rounded to one decimal place (ratio). The ratios and average number of each component contained in one molecule are: 1 H-NMR analysis and 13 This was determined from 1C-NMR analysis. [ka]

[0030] The values ​​of m and n used to express the ratio as integers may be the same or different, and are between 1 and 1000, preferably 2 and 800, more preferably 5 and 600, and even more preferably 10 and 400. l is 0 to 1000, preferably 1 to 700, more preferably 2 to 400, and even more preferably 5 to 100.

[0031] The compound represented by formula (II) may be a random copolymer in which copolymer components (L), (M), and (N) are randomly copolymerized, or a block copolymer in which at least one of the copolymer components (L), (M), and (N) acts as a block, but a random copolymer is preferred. The polyester resin of the present invention may be one or more polyester resins, as long as the above m, n, and l are satisfied.

[0032] The compound represented by formula (II) can be prepared in a 2-gallon free radical continuous polymerization reactor system, for example, by referring to the descriptions in Patent Documents 1-3, U.S. Patent Application No. 09 / 354350, and U.S. Patent Application No. 09 / 614402, but a compound with modified epoxy groups is used.

[0033] The content of the compound represented by formula (II) is 0.0002 to 5.9% by weight, preferably 0.0005 to 5.0% by weight, more preferably 0.001 to 4.5% by weight, even more preferably 4.0% by weight or less, and particularly preferably 3.5% by weight or less, based on 100% by weight of the alcohol component which is a constituent of the polyester resin. When the content of the compound represented by formula (II) is less than 0.0002% by weight, drawdown occurs during molding, resulting in unstable molding or, even if molding is successful, the molded product tends to have uneven thickness. On the other hand, when the content of the compound represented by formula (II) exceeds 5.9% by weight, gelation occurs, melt fracture occurs during molding, resulting in poor surface smoothness and devitrified molded products. Furthermore, there is a tendency for the molded product to be of low quality due to the presence of gel.

[0034] The compound represented by formula (II) may have a predetermined weight-average molecular weight, which is preferably 250 to 500,000, more preferably 500 or more, even more preferably 700 or more, even more preferably 1,000 or more, even more preferably 300,000 or less, even more preferably 100,000 or less, even more preferably 50,000 or less. If the weight-average molecular weight of the compound represented by formula (II) is less than 250, unreacted compounds may bleed out onto the surface of the molded product, potentially contaminating the surface. On the other hand, if the weight-average molecular weight of the compound represented by formula (II) exceeds 500,000, when a molded product made of polyester resin is bent, the compatibility between the compound and the polyester deteriorates, potentially causing voids and whitening. The weight-average molecular weight can be determined, for example, by GPC on a standard polystyrene basis. Specifically, the weight-average molecular weight can be determined by weighing 4 mg of a sample of the compound represented by formula (II), dissolving it in 4 ml of a mixed solvent of chloroform and isofluoroisopropanol (60 / 40 vol%), filtering it through a 0.2 μm membrane filter, subjecting the resulting sample solution to GPC, and converting it to standard polystyrene.

[0035] The dicarboxylic acid and diol components used in this invention are as follows:

[0036] Examples of dicarboxylic acid components include saturated aliphatic dicarboxylic acids or their ester-forming derivatives (for example, alkyl esters of these with 1 to 20 carbon atoms), such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid, etc., and unsaturated aliphatic dicarboxylic acids or their ester-forming derivatives (for example, these Examples include aromatic dicarboxylic acids or ester-forming derivatives thereof, such as alkyl esters having 1 to 20 carbon atoms, orthophthalic acid, isophthalic acid, terephthalic acid, 5-(alkali metal) sulfoisophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-biphenylsulfondicarboxylic acid, 4,4'-biphenyletherdicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, pamoic acid, anthracenedicarboxylic acid, etc. (for example, alkyl esters of these having 1 to 20 carbon atoms, preferably dimethyl terephthalate).

[0037] Of these dicarboxylic acid components, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid are preferred, with terephthalic acid being particularly preferred in terms of the physical properties of the resulting polyester resin.

[0038] In addition to the dicarboxylic acids mentioned above, small amounts of trivalent to tetravalent carboxylic acids may also be used. Examples of carboxylic acids include ethane acid, tricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3',4'-biphenyltetracarboxylic acid, and their ester-forming derivatives (for example, alkyl esters of these having 1 to 20 carbon atoms).

[0039] As an alcohol component, a diol component is used along with the compound represented by formula (II). The diol component (excluding the compound represented by formula (II)) is preferably 99.9998 to 94.1% by weight of 100% by weight of the alcohol component, more preferably 99.9995 to 95% by weight, even more preferably 99.999 to 95.5% by weight, particularly preferably 96% by weight or more, and most preferably 96.5% by weight or more. The diol component is preferably ethylene glycol. The ethylene glycol is preferably present in an amount of 85 mol% or more, and more preferably in an amount of 85 to 99 mol%, of 100 mol% of the diol component. Diols other than ethylene glycol that may be used include 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, isosorbide, polyethylene glycol (with 4 or more ethylene units), polytrimethylene glycol, polytetramethylene glycol, aliphatic glycols such as fluoroanol, hydroquinone, and 4,4'-dihydroxybisulfite. Examples of aromatic glycols include phenol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-bis(β-hydroxyethoxyphenyl)sulfone, bis(p-hydroxyphenyl) ether, bis(p-hydroxyphenyl)sulfone, bis(p-hydroxyphenyl)methane, 1,2-bis(p-hydroxyphenyl)ethane, bisphenol A, bisphenol F, bisphenol S, bisphenol C, 2,5-naphthalenediol, glycols obtained by adding ethylene oxide to these glycols, and compounds obtained by adding water to bisphenol A, F, S, and C.

[0040] In addition to the above-mentioned diol components, trivalent to tetravalent alcohols, hydroxycarboxylic acids, cyclic esters, etc., may also be used as diol components.

[0041] Examples of such alcohols include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, and hexanetriol.

[0042] Examples of hydroxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, 4-hydroxycyclohexanecarboxylic acid, or ester-forming derivatives thereof (for example, alkyl esters having 1 to 20 carbon atoms).

[0043] Examples of cyclic esters include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolides, and lactides.

[0044] The polyester resin of the present invention preferably contains terephthalic acid in an amount of 85 to 100 mol% of the dicarboxylic acid component, and ethylene glycol as an alcohol component (more precisely, a diol component). Preferably, the ethylene glycol is present in an amount of 85 to 99 mol% of the diol component. Terephthalic acid is more preferably 90 to 100 mol%, and even more preferably 95 to 100 mol%, of the dicarboxylic acid component, and ethylene glycol is more preferably 90 to 99 mol%, and even more preferably 95 to 99 mol%, of the diol component. The polyester resin of the present invention is preferably a copolymerized polyethylene terephthalate resin.

[0045] The polyester resin of the present invention is a crystalline polyester resin having a branched structure, and can improve processability such as moldability through the "melt strength enhancement effect" of increasing molecular weight, as well as adjust the melt viscosity and melt tension, and can suppress the bending whitening resistance of molded products and the bleeding out of unreacted substances to the surface of molded products.

[0046] Furthermore, it is preferable that the polyester resin of the present invention has a reduced cyclic oligomer content. This cyclic oligomer is preferably a tetramer, and more preferably a tetramer formed by the reaction of terephthalic acid and ethylene glycol (hereinafter also referred to as CT4), that is, a cyclic tetramer in which terephthalic acid, ethylene glycol, terephthalic acid, ethylene glycol, terephthalic acid, ethylene glycol, terephthalic acid, and ethylene glycol are cyclically bonded in that order. The content of cyclic oligomer tetramers in the polyester resin is preferably less than 2680 ppm, more preferably 2650 ppm or less, even more preferably 2600 ppm or less, preferably more than 0 ppm, more preferably 1 ppm or more, even more preferably 10 ppm or more, and even more preferably 100 ppm or more. Keeping the free CT4 level below 2680 ppm suppresses bleed-out to the surface of molded products, improving the transparency of molded products and films, maintaining high quality, and even allowing for sufficient transparency in thick molded products and films. Furthermore, when CT4 levels exceed 2680 ppm, contamination tends to become very severe near the resin outlet of the extrusion molding machine die and in the molds of injection molding machines during continuous film deposition and fiber extrusion. In addition, free CT4 that bleeds out to the surface of molded products tends to adhere to the surface of films, molded products, and fibers, reducing their commercial value. Although the mechanisms are unclear, the polyester contains dicarboxylic acid and alcohol components, and the content of the compound represented by formula (II) is 0.0002 to 5.9% by weight per 100% by weight of the alcohol component. It is thought that the structure of formula (II) acts as a steric hindrance during CT4 ring formation, resulting in a free CT4 concentration of less than 2680 ppm.

[0047] The polyester resin of the present invention may have a predetermined intrinsic viscosity IV. The intrinsic viscosity IV is preferably 0.40 to 2.10 dl / g, more preferably 0.50 to 1.90 dl / g, and even more preferably 0.60 to 1.70 dl / g. The intrinsic viscosity can be measured at 30°C using an Ostwald viscometer after dissolving the polyester resin in a parachlorophenol / tetrachloroethane (3 / 1:by weight) mixed solvent.

[0048] The acid value (AV) of the polyester resin used in the present invention is preferably 100eq / 10 6 g(ton) or less, more preferably 60eq / 10 6 g or less, more preferably 50 eq / 10 6 It is less than or equal to g. On the other hand, the lower the limit, the better, preferably 0eq / 10 6 The closer to g, the better. Acid value of 100 eq / 10 6 When the g value exceeds a certain level, gel formation tends to occur, leading to a decrease in surface properties and haze. The acid value can be determined by dissolving a sample of polyester resin in an alcohol and / or ether solution and titrating it with an alcoholic sodium hydroxide solution or an alcoholic potassium hydroxide solution using phenolphthalein reagent as an indicator. The specific method for measuring the acid value is shown in the examples.

[0049] The polyester resin of the present invention may have a predetermined melting point, which is preferably 200 to 300°C, more preferably 220 to 280°C, even more preferably 240 to 260°C, and even more preferably 250°C or higher. The melting point can be determined using a differential scanning calorimetry (DSC) at a heating rate of 20°C / min up to 300°C, and the maximum peak temperature of the heat of fusion can be identified as the crystalline melting point.

[0050] The polyester resin of the present invention is preferably produced via a polymerization catalyst containing at least an aluminum compound and a phosphorus compound, and preferably has an aluminum content of 3 to 1000 ppm and a phosphorus content of 5 to 10000 ppm derived from the polymerization catalyst. As other polymerization catalysts, one or more selected from titanium compounds and germanium compounds may be used, or a combination of phosphorus compounds and germanium compounds may be used.

[0051] The aluminum compound is preferably at least one selected from aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, and aluminum hydroxide chloride, more preferably at least one selected from aluminum acetate and basic aluminum acetate, and even more preferably aluminum acetate. The amount of aluminum is preferably 3 to 1000 ppm, more preferably 5 to 800 ppm, and even more preferably 8 to 500 ppm, as aluminum atoms relative to the total mass of the polyester resin. If the amount of aluminum is too low, the polymerization activity may decrease, and if the amount of aluminum is too high, a large amount of aluminum-derived foreign matter may be generated.

[0052] The phosphorus compound used as a polymerization catalyst together with the aluminum compound will be described. The phosphorus compound is preferably at least one selected from phosphonic acid compounds and phosphinic acid compounds, and more preferably a phosphonic acid compound.

[0053] The phosphorus compound preferably has a phenol structure within the same molecule, more preferably is at least one selected from phosphonic acid compounds and phosphinic acid compounds having a phenol structure within the same molecule, and even more preferably is a phosphonic acid compound having a phenol structure within the same molecule.

[0054] Phosphorus compounds having a phenol structure within the same molecule include p-hydroxyphenylphosphonic acid, p-hydroxyphenylphosphonic acid dimethyl, p-hydroxyphenylphosphonic acid diethyl, p-hydroxyphenylphosphonic acid diphenyl, bis(p-hydroxyphenyl)phosphinic acid, bis(p-hydroxyphenyl)phosphinic acid methyl, bis(p-hydroxyphenyl)phosphinic acid phenyl, p-hydroxyphenylphenylphosphinic acid methyl, p-hydroxyphenylphenylphosphinic acid phenyl, p-hydroxyphenylphosphinic acid methyl, p-hydroxyphenylphosphinic acid phenyl, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid diethyl.

[0055] In particular, the phosphorus compound is preferably diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate. Such a phosphorus compound can be, for example, Irgamod® 295 (manufactured by BASF).

[0056] The phosphorus content is preferably 5 to 10,000 ppm, more preferably 8 to 8,000 ppm, and even more preferably 10 to 6,000 ppm, as phosphorus atoms, relative to the total mass of the polyester resin. If the phosphorus content is too low, polymerization activity will decrease and a large amount of aluminum-derived impurities may be generated. If the phosphorus content is too high, catalyst costs may increase.

[0057] Titanium compounds include tetrabutyl titanium, tetrabenzyl titanium, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-tert-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, lithium titanate oxalate, potassium titanate oxalate, ammonium titanate oxalate, titanium oxide, composite oxides of titanium with silicon, zirconium, alkali metals, alkaline earth metals, etc., orthoesters or condensed orthoesters of titanium, orthoesters of titanium. Examples of reaction products include those consisting of a condensed orthoester and a hydroxycarboxylic acid, a reaction product consisting of a titanium orthoester or condensed orthoester with a hydroxycarboxylic acid and a phosphorus compound, and a reaction product consisting of a titanium orthoester or condensed orthoester with a polyhydric alcohol having at least two hydroxyl groups, a 2-hydroxycarboxylic acid and a base. Of these, tetrabutyltitanium, a composite oxide of titanium and silicon, a composite oxide of titanium and magnesium, and a reaction product consisting of a titanium orthoester or condensed orthoester with a hydroxycarboxylic acid and a phosphorus compound are preferred. The amount of titanium is preferably 1 to 300 ppm, more preferably 2 to 200 ppm, and even more preferably 3 to 100 ppm, as titanium atoms, relative to the total mass of the polyester resin. Examples of germanium compounds include germanium dioxide and germanium acetate. Among these, germanium dioxide is preferred. The amount of germanium is preferably 1 to 500 ppm, more preferably 2 to 400 ppm, and even more preferably 3 to 300 ppm, as germanium atoms, relative to the total mass of the polyester resin. The amount of the above atoms may be calculated, for example, by X-ray fluorescence analysis.

[0058] Furthermore, as phosphorus compounds used with germanium compounds, phosphoric acid and phosphate esters such as trimethyl phosphate, triethyl phosphate, phenyl phosphate, and triphenyl phosphate, as well as phosphorous acid and phosphate esters such as trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, and tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylenediphosphite may be used.

[0059] The polyester resin of the present invention preferably has a predetermined melt tension and melt viscosity when melted.

[0060] The polyester resin of the present invention has the property that its melt tension decreases as the temperature increases above 250°C. In this invention, from the viewpoint of exhibiting performance equivalent to or better than that of high-density polyethylene, the melt tension is set at a temperature of 270°C, a draw speed of 100 m / min, and a shear speed of 243 s. -1 The melt tension is preferably 15 mN or more, more preferably 17 mN or more, and even more preferably 19 mN or more, and the upper limit of the melt tension is, for example, 170 mN or less or 120 mN or less. The melt tension is measured, for example, using a capillary rheometer under predetermined conditions (capillary length 10 mm, capillary diameter 1 mm, temperature 270°C, shear rate 243 s). -1 This can be determined by using a maximum pickup speed of 200 m / min, a pickup start speed of 10 m / min, or a pickup speed of 100 m / min (constant) with a pickup time of 90 seconds.

[0061] The polyester resin of the present invention has a shear rate of 2000 s at melting. -1 Furthermore, it has the property that the melt viscosity decreases as the temperature increases above 250°C. In this invention, from the viewpoint of suppressing the generation of melt fractures during melt extrusion, the melt viscosity is set at a temperature of 270°C and a shear rate of 30 s. -1 Therefore, the pressure is 26,000 dPa·s or higher, the temperature is 270°C, and the shear rate is 2000 s. -1Preferably, the pressure is 6500 dPa·s or less. The polyester resin of the present invention exhibits thixotropy at high temperatures during melting, which suppresses the occurrence of melt fracture and provides good moldability.

[0062] The melt viscosity was determined at a temperature of 270°C and a shear rate of 30 s. -1 The viscosity is preferably 26,000 dPa·s or higher, more preferably 28,000 dPa·s or higher, and even more preferably 30,000 dPa·s or higher. The upper limit of the melt viscosity is, for example, 50,000 dPa·s or less, or 45,000 dPa·s or less.

[0063] The melt viscosity was calculated at a temperature of 270°C and a shear rate of 2000 s. -1 The viscosity is preferably 6500 dPa·s or less, more preferably 6300 dPa·s or less, and even more preferably 6200 dPa·s or less, and the lower limit of the melt viscosity is, for example, 5500 dPa·s or more.

[0064] The melt viscosity can be measured, for example, according to JIS K7199. The melt viscosity is measured using a capillary rheometer under predetermined conditions (capillary length 10 mm, capillary diameter 1 mm, temperature 270°C, shear rate 30 s). -1 or 2000s -1 It can be obtained using ).

[0065] The polyester resin of the present invention may have a predetermined heat-resistant oxidative decomposition parameter (TOD) from the viewpoint of heat resistance, and the heat-resistant oxidative decomposition parameter (TOD) of the polyester resin is preferably 0.390 or less. TOD can be calculated by the method described in the section of the Examples below. TOD is more preferably 0.385 or less, even more preferably 0.380 or less, particularly preferably 0.375 or less, and most preferably 0.370 or less. The lower limit of TOD is, for example, 0.010 or more, 0.015 or more, or 0.020 or more. If TOD exceeds 0.390, there is a risk that the moldability during drawdown will decrease.

[0066] The polyester resin of the present invention may contain additives such as organic, inorganic, and organometallic toners, as well as fluorescent whitening agents. By including one or more of these additives, discoloration such as yellowing of the polyester resin can be suppressed to an even better level. Other arbitrary polymers, antistatic agents, defoaming agents, dyeability improvers, dyes, pigments, matting agents, fluorescent whitening agents, stabilizers, antioxidants, and other additives may also be included. As antioxidants, aromatic amine-based and phenol-based antioxidants can be used, and as stabilizers, phosphorus-based (such as phosphoric acid and phosphate esters), sulfur-based, and amine-based stabilizers can be used.

[0067] Furthermore, the polyester resin can be directly introduced into the molding process in a molten state after the melt polycondensation process is completed as described above, or in a chip state after further processing such as solid-phase polymerization, to form a molded article. Alternatively, a predetermined amount of additives, such as crystallization property improvers, aldehyde reducers, color improvers, stabilizers, etc., can be added to any reactor or transport piping in the manufacturing process of the melt polycondensation polymer, and after melt polycondensation to achieve the desired properties, it can be directly introduced into the molding process either as is, or after further processing such as solid-phase polymerization, to form a molded article.

[0068] A polyester resin molded article made from the polyester resin of the present invention may have a predetermined center surface mean (SRa) of three-dimensional roughness. The SRa of the polyester resin molded article is preferably less than 0.15 μm, more preferably 0.14 μm or less, even more preferably 0.13 μm or less, even more preferably 0.12 μm or less, and preferably 0.01 μm or more or 0.02 μm or more. The center surface average (SRa) of the three-dimensional roughness can be determined, for example, using a surface roughness measuring instrument (micro-shape measuring instrument, SurfCorder ET4000A manufactured by Kosaka Laboratory).

[0069] 2. Method for producing polyester resin The polyester resin of the present invention can be manufactured by conventionally known methods. For example, when manufacturing PET, it can be produced by a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and optionally other copolymer components, water is distilled off to esterify, and then polycondensation is carried out under reduced pressure; or by a transesterification method in which dimethyl terephthalate is reacted with ethylene glycol and optionally other copolymer components, methyl alcohol is distilled off to transesterify, and then polycondensation is carried out under reduced pressure. Furthermore, solid-phase polymerization may be carried out as needed to increase the intrinsic viscosity. To promote crystallization before solid-phase polymerization, the molten polymerized polyester may be subjected to heat crystallization after absorbing moisture, or water vapor may be directly blown onto the polyester chips to induce heat crystallization. Regarding the method of adding the compound represented by formula (II), it is preferable to add it during polymerization. The compound represented by formula (II) may be added in a dispersed state at the time of addition.

[0070] The polycondensation reaction may be carried out in a batch reactor or a continuous reactor. In either of these methods, the esterification or transesterification reaction may be carried out in one step or in multiple steps. The polycondensation reaction may be carried out in one step or in multiple steps. The solid-phase polymerization reaction can be carried out in a batch reactor or a continuous reactor, similar to the polycondensation reaction. Polycondensation and solid-phase polymerization may be carried out continuously or in stages. Below, we will describe an example of a preferred continuous manufacturing method using PET as the polyester resin.

[0071] The esterification reaction is carried out using a multi-stage apparatus consisting of 1 to 3 esterification reactors connected in series, under reflux conditions of ethylene glycol, while removing the water or alcohol produced by the reaction from the system using a rectification column. The temperature of the first stage esterification reaction is preferably 240 to 270°C, more preferably 245 to 265°C, and the pressure is preferably 0.2 to 3 kg / cm². 2 G, more preferably 0.5~2 kg / cm³ 2The final esterification reaction temperature is typically 250-290°C, preferably 255-275°C, and the pressure is typically 0-1.5 kg / cm². 2 G, preferably 0-1.3 kg / cm³ 2 G. When the process is carried out in three or more steps, the reaction conditions for the intermediate esterification reaction are between the reaction conditions for the first step and the reaction conditions for the final step. It is preferable that the increase in the reaction rate of these esterification reactions is distributed smoothly at each step. Ultimately, it is desirable that the esterification reaction rate reaches preferably 90% or more, more preferably 93% or more. These esterification reactions yield a lower-order condensate with a molecular weight of about 500 to 5000.

[0072] The above esterification reaction, when using terephthalic acid as a starting material, can be carried out without a catalyst due to the catalytic action of terephthalic acid as an acid, but it may also be carried out in the presence of a polycondensation catalyst.

[0073] Furthermore, it is preferable to add small amounts of tertiary amines such as triethylamine, tri-n-butylamine, and benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, and trimethylbenzylammonium hydroxide, and basic compounds such as lithium carbonate, sodium carbonate, potassium carbonate, and sodium acetate, and then perform polycondensation, as this allows the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate to be maintained at a relatively low level (5 mol% or less relative to the total diol components).

[0074] Next, when producing a low polymer by transesterification, a solution containing preferably 1.1 to 3.0 moles, more preferably 1.2 to 2.5 moles, of ethylene glycol per mole of dimethyl terephthalate is prepared and continuously supplied to the transesterification reaction step.

[0075] The transesterification reaction is carried out using an apparatus consisting of one or two transesterification reactors connected in series, under conditions of reflux of ethylene glycol, while removing the methanol produced by the reaction from the system using a rectification column. The temperature of the first stage of the transesterification reaction is preferably 180 to 250°C, more preferably 200 to 240°C. The temperature of the final stage of the transesterification reaction is usually 230 to 270°C, preferably 240 to 265°C, and fatty acid salts and carbonates of Zn, Cd, Mg, Mn, Co, Ca, Ba, etc., or oxides of Pb, Zn, Sb, Ge may be used as the transesterification catalyst. These transesterification reactions yield lower-order condensates with a molecular weight of approximately 200 to 500.

[0076] The obtained lower-order condensate is then supplied to a multi-stage liquid-phase condensation polymerization process. The polycondensation reaction conditions are as follows: for the first stage of polycondensation, the reaction temperature is preferably 250-290°C, more preferably 260-280°C, and the pressure is preferably 500-20 Torr, more preferably 200-30 Torr; for the final stage of polycondensation, the reaction temperature is preferably 265-300°C, more preferably 275-295°C, and the pressure is preferably 10-0.1 Torr, more preferably 5-0.5 Torr. If the process is carried out in three or more stages, the reaction conditions for the intermediate stage of polycondensation are between the reaction conditions for the first stage and the reaction conditions for the final stage. It is preferable that the degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is smooth.

[0077] The polycondensed polyester resin obtained in this manner is then subjected to solid-phase polymerization. The polyester resin is subjected to solid-phase polymerization by a conventionally known method. First, the polyester resin to be subjected to solid-phase polymerization is precrystallized by heating at a temperature of, for example, 100 to 190°C for 1 to 5 hours under an inert gas atmosphere, under reduced pressure, or under a water vapor or water vapor-containing inert gas atmosphere. Then, solid-phase polymerization is carried out at a temperature of 190 to 230°C for 1 to 50 hours under an inert gas atmosphere or under reduced pressure.

[0078] The catalyst used in this invention exhibits catalytic activity not only in polycondensation reactions but also in esterification and transesterification reactions. For example, the catalyst can be used in the transesterification reaction between alkyl esters of dicarboxylic acids such as dimethyl terephthalate and glycols such as ethylene glycol. Furthermore, the catalyst used in this invention exhibits catalytic activity not only in melt polymerization but also in solid-phase polymerization and solution polymerization, making it possible to produce polyester resins by any of these methods.

[0079] The polymerization catalyst used in this invention can be added to the reaction system at any stage of the polymerization reaction. For example, it can be added before the start of the esterification reaction or transesterification reaction, at any stage during the reaction, immediately before the start of the polycondensation reaction, or at any stage during the polycondensation reaction. In particular, it is preferable to add aluminum or an aluminum compound immediately before the start of the polycondensation reaction.

[0080] The method of adding polymerization catalysts other than phosphorus compounds used in this invention is not particularly limited and may be in powder or neat form, or in slurry or solution form of a solvent such as ethylene glycol. Furthermore, aluminum or an aluminum compound or phosphorus compound may be added as a pre-mixed mixture with other components, or these may be added separately. Also, aluminum or an aluminum compound or phosphorus compound and other components may be added to the polymerization system at the same time, or each component may be added at different times. Furthermore, the entire amount of catalyst may be added at once or in multiple installments.

[0081] The polyester resin of the present invention is preferably subjected to blow molding (preferably direct blow molding) after polycondensation and solid-phase polymerization. In blow molding of heat-resistant bottles, a bottomed precursor called a preform is generally prepared, and this preform may be blow-stretched in a mold and then heat-set. Methods such as compression molding and injection molding are used to manufacture the preform. Taking injection molding as an example, the preform can be obtained by heating and melting it to 260-350°C and injecting it into the mold of the preform. Typically, the preform has a thick-walled test tube shape with a gate at the bottom and a screw for a cap at the opening.

[0082] In heat-resistant bottles, the mouthpiece portion of the resulting preform may be crystallized. Crystallization prevents deformation of the mouthpiece portion even when filling with high-temperature contents. Crystallization of the mouthpiece portion is preferably carried out by heating to 130-200°C, more preferably 140-190°C. Heating methods include infrared heaters, hot air, induction heating, and immersion in an oil bath, with infrared heaters being preferred from the standpoint of productivity. Note that heating and crystallization of the mouthpiece portion may also be performed after blow molding.

[0083] A bottle is obtained by heating a preform, stretching it in the length direction (vertical direction) and blow-molding it in the circumferential direction. In the length direction, it is usually stretched with a rod-shaped stretching rod, and in the circumferential direction, a pressurized gas such as air or nitrogen is used. The pressurized gas is preferably 1 to 10 MPa. It is preferable to blow in the pressurized gas while inserting the stretching rod to stretch it simultaneously in the length direction and circumferential direction, but it may also be stretched in the length direction first and then in the circumferential direction. For heating, infrared heaters, hot air, induction heating, etc. are used. The heating temperature is usually 80 to 130°C, preferably 90 to 120°C.

[0084] The lower limit of the stretching ratio in the length direction of the bottle is preferably 1.5 times, more preferably 2 times. If it is less than the above, uneven stretching may occur. The upper limit of the stretching ratio in the length direction of the bottle is preferably 6 times, more preferably 5 times, and even more preferably 4 times. If it exceeds the above, tearing and other problems are more likely to occur.

[0085] The lower limit of the stretching ratio in the circumferential direction of the bottle is preferably 2 times, more preferably 2.5 times. If it is less than the above, uneven stretching may occur. The upper limit of the stretching ratio in the circumferential direction of the bottle is preferably 6 times, more preferably 5 times, and even more preferably 4 times. If it exceeds the above, tearing and other problems are more likely to occur.

[0086] When heat setting is performed in the same mold immediately after blow molding, the lower limit of the blow molding mold temperature is preferably 80°C, more preferably 120°C, even more preferably 130°C, and most preferably 140°C. If the temperature is lower than the above, sufficient crystallization may not be promoted during the subsequent heat setting, resulting in insufficient heat resistance, or a longer heat setting time may be required, leading to a decrease in productivity.

[0087] The upper limit of the mold temperature is preferably 350°C, more preferably 340°C, even more preferably 330°C, and particularly preferably 320°C, and the lower limit of the mold temperature is preferably 280°C, more preferably 290°C, and even more preferably 300°C. The polyester resin of the present invention has the property that its melt tension decreases as the temperature during melting increases. Therefore, when the mold temperature is increased, the melt tension decreases when the mold and the polyester resin come into contact, reducing the occurrence of melt fractures. On the other hand, after being discharged from the mold, the melt tension increases, reducing the occurrence of drawdown.

[0088] The blow-molded bottle is then heat-set in the mold. The lower limit of the heat-set time is preferably 0.5 seconds, more preferably 1 second, and even more preferably 1.5 seconds. If it is shorter than the above, sufficient crystallization may not occur, resulting in insufficient heat resistance. The upper limit of the heat-set time is preferably 15 seconds, more preferably 10 seconds, and even more preferably 5 seconds. Long heat-set times not only reduce productivity, but in the case of rotary blow molding machines, it is necessary to have many molds, and if the equipment becomes large, it may be less economical. After heat-setting in the mold, additional heat-setting may be performed by heating with infrared, hot air, induction heating, etc.

[0089] Alternatively, blow molding can be performed in a mold at 5-50°C, followed by heat setting in a heated mold. In this case, the temperature of the heat setting mold is the same as the mold temperature in the above-mentioned case.

[0090] A blow molding apparatus may have a single mold, but for mass production, it is preferable to have multiple molds that sequentially move through locations where the heated preform is set, stretched, heat-set, and the bottle is discharged. Although the cold parison method, in which the cooled preform is reheated, is described above, the hot parison method, in which blow molding is performed without completely cooling the preform, is also possible.

[0091] The capacity of the molded bottle is preferably 200ml to 6L, and more preferably 300ml to 2L. The shape of the bottle body can be any shape, such as circular, square (including shapes with cut corners), or hexagonal.

[0092] The polyester resin of the present invention is subjected to blow molding (preferably direct blow molding) and is suitably used for containers (e.g., bottles) for cosmetics, detergents, beverages, etc.

[0093] This application claims the benefit of priority based on Japanese Patent Application No. 2020-207928, filed on 15 December 2020. The entire specification of Japanese Patent Application No. 2020-207928, filed on 15 December 2020, is incorporated herein by reference. [Examples]

[0094] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0095] Measurement of the intrinsic viscosity IV of polyester resin The polyester resin was dissolved in a mixed solvent of parachlorophenol / tetrachloroethane (3 / 1:by weight ratio), and the viscometer was measured at 30°C using an Ostwald viscometer.

[0096] Measurement of the composition of polyester resin The composition of the polyester resin was determined using a RUKER AVANCE NEO600 Fourier transform nuclear magnetic resonance spectrometer in deuterated chloroform solvent. 1 H-NMR analysis and 13 The result was determined by performing 1C-NMR analysis and analyzing the integral ratio.

[0097] Measurement of the melting point of polyester resin 5 mg of polyester resin was placed in an aluminum sample pan and sealed. The temperature was measured up to 300°C at a heating rate of 20°C / min using a differential scanning calorimetry analyzer (DSC) DSC-Q100 manufactured by T.A. Instruments Japan Co., Ltd., and the maximum peak temperature of the heat of fusion was determined as the crystalline melting point.

[0098] Gel measurement 30 g of melt-polycondensed polyester pellets and 300 ml of a mixed solution of parachlorophenol / tetrachloroethane (3 / 1:by weight) were placed in a round-bottom flask equipped with a stirrer, and the pellets were stirred and dissolved in the mixed solution at 100-105°C for 2 hours. The solution was allowed to cool to room temperature, and the entire volume was filtered to remove impurities under a pressure of 0.15 MPa using a polytetrafluoroethylene membrane filter with a diameter of 47 mm and a pore size of 1.0 μm (Advantec PTFE membrane filter, product name: T100A047A). The effective filtration diameter was 37.5 mm. After filtration, the membrane was washed with 300 ml of chloroform and then dried under reduced pressure at 30°C overnight. The filtration surface of the membrane filter was observed with an optical microscope to determine the presence or absence of undissolved material (gel).

[0099] Measurement of melt tension The melt tension of the polyester resin was measured using the following equipment and conditions during molding. Capillary rheometer (Toyo Seiki Seisakusho) Temperature: 270℃ Capillary length: 10mm Capillary diameter: 1mm Shear rate: 243s -1 Maximum pickup speed: 200m / min Pickup start speed: 10m / min Alternatively, the pickup speed is 100 m / min (constant). Pickup time: 90 seconds

[0100] Measurement of melt viscosity The melt tension of the polyester resin was measured using the following equipment and conditions during molding. Capillary rheometer (Toyo Seiki Seisakusho) Capillary length: 10mm Capillary diameter: 1mm Temperature: 270℃ Shear rate: 30s -1 or 2000s -1

[0101] Measurement of acid value (concentration of terminal carboxyl groups (unit: eq / ton, expressed as acid value)) 0.5 g of polyester resin was dissolved in 25 ml of benzyl alcohol and titrated using a benzyl alcohol solution of 0.01 mol / l sodium hydroxide. The indicator used was a solution of 0.10 g of phenolphthalein dissolved in a mixture of 50 ml of ethanol and 50 ml of water.

[0102] Measurement of the amounts of aluminum, phosphorus, and germanium atoms in polyester resin Sample pieces were prepared by heating and melting polyester resin to its melting point +20°C inside a stainless steel circular ring with a thickness of 5 mm and an inner diameter of 50 mm. Elemental amounts were determined by X-ray fluorescence analysis and expressed in ppm. A calibration curve, derived from samples with known elemental amounts, was used to determine the amounts.

[0103] Deformed extrusion molding (evaluation of formability (drawdown), mechanical properties, surface smoothness, and transparency) A polyester resin was prepared by setting the cylinder temperature to 270°C, attaching a die lip to a single-screw extruder (L / D=30, full-flight screw, screw diameter 50mm), then attaching a sizing die to the front of a cooling water tank to determine the final dimensions of the extruded product. The product was then molded using an extrusion molding facility equipped with a take-up machine, passing through the water tank. The drawdown during molding, the mechanical properties of the molded product, surface smoothness, and transparency were evaluated according to the following criteria. The results are shown in Table 2.

[0104] Evaluation of moldability (drawdown) The drawdown was evaluated according to the following criteria. ◎: No sagging of the polyester resin occurs during molding, and the shape is maintained. ○: A slight drip of polyester resin occurs during molding. △: Polyester resin drips during molding, making stable mass production impossible. ×: Due to the dripping of polyester resin during molding, the resin cannot be passed from the die lip to the sizing mold.

[0105] Evaluation of the mechanical properties (strength) of molded products Polyester resin molded products were bent 180° and evaluated according to the following criteria. ○: No cracks ×: Cracked

[0106] Evaluation of surface smoothness The surface roughness of the outer surface of polyester resin molded products was measured using a Kosaka Laboratory SurfCorder Et4000A, and compared according to the following criteria based on the center-plane average (SRa) of the three-dimensional roughness. ◎: SRa is less than 0.1 μm ○: SRa is 0.1 μm or more and less than 0.15 μm ×: SRa is 0.15 μm or larger

[0107] Transparency Assessment Polyester resin molded products were cut into 3cm squares and measured using a NDH-5000 haze meter manufactured by Nippon Denshoku Industries, and evaluated according to the following criteria. ◎: Haze is less than 5% ○: HAZE is between 5% and less than 10% ×: HAZE is 10% or more

[0108] Evaluation of heat resistance (thermal oxidation stability parameter (TOD)) Polyester resin chips ([IV] i The ) was cryopreserved and ground into a powder of 20 mesh or less. This powder was vacuum dried at 130°C for 12 hours, and 300 mg of the powder was placed in a glass test tube with an inner diameter of approximately 8 mm and a length of approximately 140 mm and vacuum dried at 70°C for 12 hours. Then, a drying tube containing silica gel was attached to the top of the test tube and immersed in a nitrate bath at 230°C under dry air and heated for 15 minutes, after which [IV] f1 The following was measured. TOD was calculated as follows. However, [IV] i and [IV] f1The values ​​of IV (dL / g) before and after the heating test are shown, respectively. Freeze grinding was performed using a freezer mill (Specx, USA, Model 6750). Approximately 2g of resin chips and a dedicated impactor were placed in a dedicated cell, the cell was set in the apparatus, liquid nitrogen was filled into the apparatus and held for approximately 10 minutes, and then grinding was performed for 5 minutes at RATE 10 (impactor rotations approximately 20 times per second). TOD=0.245{[IV] f1 -1.47 -[IV] i -1.47} For polyester resins, a lower TOD (Temperature of Dose) value indicates higher heat resistance.

[0109] Evaluation of CT4 content 50 mg of polyester resin was dissolved in 1 ml of a hexafluoroisopropanol / chloroform mixture (volume ratio = 1 / 9), and further diluted with 4 ml of chloroform. 10 ml of methanol was added to precipitate the polyester resin, and the mixture was then centrifuged. The supernatant after centrifugation was concentrated to dryness, redissolved in 0.4 ml of dimethylformamide, and the CT4 content was measured by high-performance liquid chromatography. Equipment: Waters ACQUITY UPLC Column: Waters BEH-C18 2.1 x 150 mm (Waters brand)

[0110] Evaluation of transparency during continuous molding Dry polyester resin was fed into an extruder equipped with a sheet die and continuously molded into sheets approximately 0.5 mm thick at 280°C for two days. The degree of contamination at the die outlet and the condition of the sheet surface were visually evaluated according to the following criteria. (Evaluation Criteria) ◎: Almost no dirt or debris adhering to the die exit, and the sheet surface is in good condition. ○: There is slight dirt adhering to the die exit, but the sheet surface is in good condition. △: There is some dirt adhering to the die exit, and some foreign matter adhering to the sheet surface. ×: The die exit has very severe contamination, and there is a lot of residue on the sheet surface.

[0111] Synthesis Examples 1-6 (Preparation of Compounds Represented by Formula (II) (Branching Agents)) The compounds represented by formula (II) were prepared in a 2-gallon free radical continuous polymerization reactor system with reference to Patent Documents 1-3, U.S. Patent Application No. 09 / 354350, and U.S. Patent Application No. 09 / 614402. The compositions of the compounds represented by formula (II) obtained in Synthesis Examples 1-6 are shown in Table 1 below. The weight-average molecular weight of the compound represented by formula (II) was calculated using GPC on a standard polystyrene basis. Specifically, 4 mg of the compound represented by formula (II) was weighed, dissolved in 4 ml of a mixed solvent of chloroform and isofluoroisopropanol (60 / 40 vol%), filtered through a 0.2 μm membrane filter, and the resulting sample solution was measured using GPC to determine the weight-average molecular weight on a standard polystyrene basis.

[0112] Furthermore, l, m, and n of the compound represented by formula (II) are: 1 H-NMR, and 13 This was determined by 13C-NMR analysis. In other words, l, m, and n were expressed as integers, rounded to one decimal place as the average number. Specifically, the sample of the compound represented by formula (II) 1 In 1H-NMR, a deuterated chloroform / trifluoroacetic acid mixed solvent (volume ratio 85 / 15) was used. 13 For 1C-NMR, the sample is dissolved in deuterated chloroform or a deuterated chloroform / hexafluoroisopropanol mixed solvent (volume ratio 1 / 1), and then measured using a Fourier transform nuclear magnetic resonance spectrometer (BRUKER AVANCE NEO600) for 50 to 200 condensation cycles. 1 H-NMR), 10,000 times ( 13 The measurements were taken under 13C-NMR conditions at room temperature. 1 H-NMR and 13 The ratio of each component and the proportion of components located at the terminals were calculated using 1C-NMR spectroscopy, and l, m, and n were determined.

[0113] In addition, the compound represented by formula (II) used in the synthesis example has the following methacrylic monomer structural unit (hereinafter abbreviated as DEMA-E structural unit) (* represents a bond with other monomer structural units (for example, styrene structural unit, methyl methacrylate structural unit)). For example, the compound containing this DEMA-E structural unit can be obtained by a method in which glycidyl methacrylate is subjected to a ring-opening reaction with water and a diol (ethylene glycol) is added, or a method in which a diol is added to glycidyl methacrylate for synthesis. After copolymerizing styrene and glycidyl methacrylate (and methyl methacrylate if necessary) according to Patent Documents 1 to 3, US Patent Application No. 09 / 354350, and US Patent Application No. 09 / 614402, the compound represented by formula (II) may be obtained by a method such as ring-opening with water and adding a diol (ethylene glycol).

[0114] <DEMA-E structural unit>

Chemical formula

[0115] The abbreviations used below are STY = styrene structural unit, MMA = methyl methacrylate structural unit, and DEMA-E structural unit (the methacrylic monomer structural unit in the above chemical formula).

[0116]

Table 1

[0117] Example 1 2593 g of terephthalic acid (manufactured by Mitsui Chemicals), 1937 g of ethylene glycol (manufactured by Nippon Shokubai), and 4 g of triethylamine (manufactured by Nacalai Tesque) were charged into a 10-liter pressure vessel equipped with a stirrer, a thermometer, and an outflow cooler, and esterification was carried out at 240 °C for 1.5 to 3.0 hours under a pressure of 0.35 MPa. While controlling the flow rate, the compound represented by formula (II) obtained in Synthesis Example 1 was continuously added so as to be 0.2% by weight based on 100% by weight of the alcohol component of the obtained polyester resin, and the reaction was allowed to proceed stepwise.

[0118] Aluminum acetate was added to the polyester resin as a polycondensation catalyst to a concentration of 30 ppm aluminum atoms (Al), and Irgamod 295 (BASF) was added to a concentration of 72 ppm phosphorus atoms (P). Then, Solvent Blue 45 (Clariant) was added to a concentration of 1 ppm relative to the polyester resin, and the mixture was stirred at 260°C for 5 minutes under atmospheric pressure and nitrogen. Subsequently, the temperature was raised to 280°C over 60 minutes while gradually lowering the pressure of the reaction system to 13.3 Pa (0.1 Torr), and the polycondensation reaction was carried out at 280°C and 13.3 Pa. The pressure was returned to atmospheric pressure with nitrogen, and the resin was discharged in strand form into cold water under slight pressure and rapidly cooled. After being held in cold water for 20 seconds, it was cut to obtain cylindrical polyester pellets with a length of approximately 3 mm and a diameter of approximately 2 mm.

[0119] Polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80°C, 12 hours), followed by crystallization treatment (13.3 Pa or less, 130°C, 3 hours, and then 13.3 Pa or less, 160°C, 3 hours). After cooling, these polyester pellets were subjected to solid-phase polymerization in a solid-phase polymerization reactor, maintaining the system pressure at 13.3 Pa or less and the temperature at 200°C to 220°C, yielding polyester pellets with an intrinsic viscosity IV of 1.18 dl / g and a TOD of 0.015.

[0120] Example 2 In Example 1, the amount of compound represented by formula (II) obtained in Synthesis Example 1 was changed to 0.001% by weight, and polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.17 dl / g and a TOD of 0.015.

[0121] Example 3 In Example 1, the amount of compound represented by formula (II) obtained in Synthesis Example 1 was changed to 3.0% by weight, and polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.20 dl / g and a TOD of 0.010.

[0122] Example 4 In Example 1, the compound represented by formula (II) obtained in Synthesis Example 1 was replaced with the compound represented by formula (II) obtained in Synthesis Example 2, and the amount added was changed to 0.2% by weight. Polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.20 dl / g and a TOD of 0.015.

[0123] Example 5 In Example 1, the compound represented by formula (II) obtained in Synthesis Example 1 was replaced with the compound represented by formula (II) obtained in Synthesis Example 3, and the amount added was changed to 0.2% by weight. Polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.15 dl / g and a TOD of 0.015.

[0124] Example 6 In Example 1, the compound represented by formula (II) obtained in Synthesis Example 1 was replaced with the compound represented by formula (II) obtained in Synthesis Example 4, and the amount added was changed to 0.2% by weight. Polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.14 dl / g and a TOD of 0.015.

[0125] Example 7 In Example 1, the compound represented by formula (II) obtained in Synthesis Example 1 was replaced with the compound represented by formula (II) obtained in Synthesis Example 5, and the amount added was changed to 0.2% by weight. Polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.09 dl / g and a TOD of 0.015.

[0126] Example 8 In Example 1, the compound represented by formula (II) obtained in Synthesis Example 1 was replaced with the compound represented by formula (II) obtained in Synthesis Example 6, and the amount added was changed to 0.2% by weight. Polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets with an intrinsic viscosity IV of 1.08 dl / g and a TOD of 0.015.

[0127] Example 9 2593g of terephthalic acid (manufactured by Mitsui Chemicals), 1937g of ethylene glycol (manufactured by Nippon Shokubai), and 4g of triethylamine (manufactured by Nacalai Tesque) were charged into a 10-liter pressure vessel equipped with a stirrer, thermometer, and outlet cooler. Esterification was carried out at 240°C under a pressure of 0.35 MPa for 1.5 to 3.0 hours. The compound represented by formula (II) obtained in Synthesis Example 1 was continuously added to 100% by weight of the alcohol component of the resulting polyester resin, while controlling the flow rate, to a total of 0.2% by weight, and the reaction was carried out in steps.

[0128] To the mass of polyester resin, germanium dioxide was added as a polycondensation catalyst to a concentration of 100 ppm germanium atoms (Ge), and triethyl phosphoric acid was added to a concentration of 50 ppm phosphorus atoms (P). Then, Solvent Blue 45 (Clariant) was added to a concentration of 1 ppm, and the mixture was stirred at 260°C for 5 minutes under atmospheric pressure and a nitrogen atmosphere. Subsequently, the temperature was raised to 280°C over 60 minutes while gradually lowering the pressure of the reaction system to 13.3 Pa (0.1 Torr), and the polycondensation reaction was carried out at 280°C and 13.3 Pa. The pressure was returned to atmospheric pressure with nitrogen, and the resin under slight pressure was discharged in strand form into cold water and rapidly cooled. After being held in cold water for 20 seconds, it was cut to obtain cylindrical polyester pellets with a length of approximately 3 mm and a diameter of approximately 2 mm.

[0129] Polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80°C, 12 hours), followed by crystallization treatment (13.3 Pa or less, 130°C, 3 hours, and then 13.3 Pa or less, 160°C, 3 hours). After cooling, these polyester pellets were subjected to solid-phase polymerization in a solid-phase polymerization reactor, maintaining the system pressure at 13.3 Pa or less and the temperature at 200°C to 220°C, yielding polyester pellets with an intrinsic viscosity IV of 1.15 dl / g and a TOD of 0.330.

[0130] Comparative Example 1 Polymerization was carried out under the same conditions as in Example 9 without adding the compound represented by formula (II), and polyester pellets with an intrinsic viscosity IV of 1.19 dl / g and a TOD of 0.400 were obtained.

[0131] Comparative Example 2 The amount of the compound represented by formula (II) obtained in Synthesis Example 1 was changed to 0.0001% by weight, and polymerization was carried out under the same conditions as in Example 9 to obtain polyester pellets with an intrinsic viscosity IV of 1.22 dl / g and a TOD of 0.400.

[0132] Comparative Example 3 The amount of the compound represented by formula (II) obtained in Synthesis Example 1 was changed to 6.0% by weight, and polymerization was carried out under the same conditions as in Example 9 to obtain polyester pellets with an intrinsic viscosity IV of 0.71 dl / g and a TOD of 0.380.

[0133] [Table 2]

[0134] In Examples 1-9, the melt viscosity was determined at a temperature of 270°C and a shear rate of 30 s. -1 Therefore, the pressure is 26,000 dPa·s or higher, the temperature is 270°C, and the shear rate is 2000 s. -1 The pressure was below 6500 dPa·s, and no gel was observed. [Industrial applicability]

[0135] The polyester resin of the present invention is expected to make a significant contribution to industry by improving moldability in extrusion molding, morph extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, which require high melt tension, and by improving mechanical properties while maintaining transparency.

Claims

1. The polyester contains dicarboxylic acid and alcohol components as constituent elements. The compound represented by formula (II) contains the following copolymer components (M), (N), and (L) as constituent units, where R1 in copolymer component (M) represents an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R2, R3, and R4 in copolymer components (N) and (L) each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the number of copolymer components (M), (N), and (L) is represented by m, n, and l, respectively, where m and n represent 1 to 1000, and l represents 0 to 1000. The content of the compound represented by formula (II) is 0.0002 to 5.9% by weight of 100% by weight of the alcohol component. A polyester resin characterized by containing terephthalic acid in an amount of 85 to 100 mol% of the dicarboxylic acid component, and ethylene glycol as an alcohol component. 【Chemistry 1】

2. The polyester resin according to claim 1, wherein the weight-average molecular weight of the compound represented by formula (II) is 250 or more and 500,000 or less.

3. The polyester resin according to claim 1 or 2, wherein the content of cyclic oligomer tetramers in the polyester resin is less than 2680 ppm.

4. The melt tension was achieved at a temperature of 270°C, a draw speed of 100 m / min, and a shear speed of 243 s. -1 The polyester resin according to any one of claims 1 to 3, wherein the N is 15 mN or more.

5. The melt viscosity is at a temperature of 270°C and a shear rate of 30 s. -1 Therefore, the pressure is 26,000 dPa·s or higher, the temperature is 270°C, and the shear rate is 2,000 s. -1 The polyester resin according to any one of claims 1 to 4, wherein the pressure is 6500 dPa·s or less.

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