Polyester resin

Abstract

The purpose of the present invention is to provide a polyester resin excellent in terms of gelation inhibition, moldability, surface smoothness, transparency, mechanical property, and heat resistance.　The present invention relates to a polyester resin characterized by comprising a dicarboxylic acid component and an alcohol component as polyester-constituting components, the content of a compound represented by formula (III) being 0.0002-5.9 wt% of the alcohol component, which is taken as 100 wt%. (In the formula, m and n are each 1-1,000, l is 0-1,000, R1 represents an aromatic hydrocarbon group having 6-20 carbon atoms, and R2, R3, and R4 each represent a hydrogen atom or an alkyl group having 1-10 carbon atoms.)

Description

[Technical Field]

[0001] The present invention relates to a polyester resin that can provide molded articles with excellent moldability, transparency, mechanical properties, and heat resistance. More specifically, the present invention relates to a polyester resin that can achieve improved moldability in extrusion molding, profile extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, all of which require high melt tension, as well as improved transparency, heat resistance, mechanical properties, and heat resistance. [Background technology]

[0002] In recent years, there has been a trend to replace vinyl chloride resins with other materials due to concerns about their environmental impact, and among the many alternative materials, polyester resins are being considered as a promising material in terms of physical properties, environmental compatibility, adhesive properties, price, etc.

[0003] Among polyester resins, crystalline polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) are used in a variety of melt-molded products, such as 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, in order to improve the transparency and flexibility of molded articles using these crystalline polyester resins, various techniques are required, such as controlling the cooling conditions during processing and performing stretching processing. Furthermore, in profile extrusion molding, direct blow molding, and inflation molding, which require high melt tension, the drawdown phenomenon becomes significant, causing the preformed or molded product to sag, resulting in uneven thickness and increased burrs in the molded product, which leads to problems of reduced yield and lower continuous production stability.

[0005] On the other hand, in order to solve the problem of the drawdown phenomenon, inventions have been disclosed that improve moldability in direct blow molding, which requires high melt tension, by introducing a branched structure (branching agent) into the resin skeleton (e.g., Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5931061 [Patent Document 2] Patent No. 5941843 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-56384 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the techniques of Patent Documents 1 to 3 have the problem that the reactivity of the branched structures (branching agents) is high, and even if they are mixed with a carboxylic acid compound and reacted with the constituent components of the polyester resin, a gel is generated, the solubility with the constituent components of the polyester resin is reduced, and the resulting polyester resin molded product does not have good surface smoothness. In addition, although the drawdown phenomenon is improved in Patent Documents 1 to 3, there is also the problem that the melt tension is too high, and when the resin is extruded from the die during molding, melt fracture occurs, reducing the surface smoothness of the molded product and decreasing the transparency of the molded product. In addition, molded products of polyester resins are also required to have heat resistance, etc. Furthermore, during the manufacturing process of polyester resins, cyclic oligomers (including tetramers) are generated, and these cyclic oligomers contaminate molds during processing, resulting in a decrease in continuous moldability, which has been a problem.

[0008] The present invention was made in view of the problems of the prior art, and an object of the present invention is to provide a polyester resin that can provide molded articles that are excellent in gelation inhibition, moldability, surface smoothness, transparency, mechanical properties, and heat resistance. Problems that are not essential to the present invention include providing a polyester resin that has a low cyclic oligomer content and can provide molded articles that are excellent in continuous moldability.

[0009] More specifically, an object of the present invention is to provide a polyester resin that is excellent in gelation inhibition, surface smoothness, transparency, mechanical properties, and heat resistance, and that can provide molded products with excellent moldability in extrusion molding, profile extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, all of which require high melt tension. [Means for solving the problem]

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

[0011] [1] A polyester resin comprising a dicarboxylic acid component and an alcohol component as polyester constituents, wherein the content of the compound represented by formula (III) is 0.0002 to 5.9% by weight based on 100% by weight of the alcohol component. [ka] (In the formula, 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 represents 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 (III) is 330 or more and 500,000 or less. [3] The polyester resin according to [1] or [2], which contains 85 to 100 mol % of terephthalic acid in 100 mol % of the dicarboxylic acid component, and contains ethylene glycol as the alcohol component. [4] The polyester resin according to any one of [1] to [3], wherein the content of cyclic oligomer tetramer in the polyester resin is less than 2680 ppm. [5] Melt tension: temperature 270°C, take-up speed 100m / min, shear rate 243s -1 The polyester resin according to any one of [1] to [4], wherein the tensile strength is 14 mN or more. [6] Melt viscosity: Temperature: 270°C, shear rate: 30 s -1 26000 dPa·s or more, temperature 270℃, shear rate 2000 s -1 The polyester resin according to any one of [1] to [5], having a viscosity of 6500 dPa·s or less. [Effects of the Invention]

[0012] According to the present invention, a molded article of a polyester resin having excellent gelation suppression, moldability, surface smoothness, transparency, mechanical properties, and heat resistance can be obtained. In particular, the moldability is superior to conventional methods in extrusion molding, profile extrusion molding, direct blow molding, inflation molding, injection blow molding, and calendering molding, which require a high melt tension. Furthermore, non-essential effects of the present invention include the ability to obtain molded articles of polyester resins that have a low cyclic oligomer content and excellent continuous moldability. DETAILED DESCRIPTION OF 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 polyester constituents, and the content of the compound represented by formula (III) is 0.0002 to 5.9% by weight based on 100% by weight of the alcohol component.

[0014] [ka] (In the formula, 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 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0015] The polyester resin of the present invention is characterized in that it contains a polymer of a predetermined dicarboxylic acid component and an alcohol component, and that the content of the compound represented by formula (III) as the alcohol component is a predetermined amount. In the present invention, the compound represented by formula (III) 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). The compound represented by formula (III) may be present as a compound in the resin composition as long as it is bonded to the polyester resin chain at an appropriate stage, but it is preferred that the compound of formula (III) be present in a state bonded to the carboxylic acid component of the polyester resin. The compound represented by formula (III) has an average of two or more (preferably three or more) functional groups (hydroxyl groups) per molecule that can react with the carboxyl groups of the dicarboxylic acid component, 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 contain epoxy groups and are highly reactive with dicarboxylic acid components, and therefore react preferentially with dicarboxylic acids over diol components typically used in polyester resins. The reaction product then reacts with the diol component to form a polyester resin having hydroxyl groups in its side chains. However, during the formation of the polyester resin, the epoxy groups contained in the branching agents may react with each other, or further with the carboxyl groups or hydroxyl groups of the polyester resin, to form a gel. The polyester resin of the present invention is formed by reacting the compound represented by formula (III), which is a branching agent having no epoxy group, with a dicarboxylic acid component.

[0017] As described above, the polyester resin of the present invention differs from the polyester resins of Patent Documents 1 to 3 in terms of resin structure, and the epoxy groups of the branching agent do not react with each other, or further the epoxy groups do not react with the carboxyl groups or hydroxyl groups of the polyester resin, thereby suppressing gelation. Furthermore, since the polyester resin of the present invention uses the compound represented by formula (III), 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 polyester resin is excellent in moldability, surface smoothness, transparency, mechanical properties, and heat resistance. Furthermore, since the polyester resin contains a small amount of cyclic oligomers, the mold is less likely to be contaminated during processing, and continuous moldability can be improved.

[0018] The compound represented by formula (III) is as follows: [ka]

[0019] (In the formula, 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 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

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

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

[0022] The aromatic hydrocarbon group preferably has 6 to 18 carbon atoms, more preferably 6 to 15 carbon atoms, and even more preferably 6 to 12 carbon atoms.

[0023] Of these, the aromatic hydrocarbon group is particularly 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 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0025] R 2 , R 3 , R 4Examples of the alkyl group having 1 to 10 carbon atoms represented by the formula (I) include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; Isopropyl, isobutyl, sec-butyl, tert-butyl, 2-ethylbutyl, 3,3-dimethylbutyl, 1,1,3,3-tetramethylbutyl, 1-methylbutyl, 1-ethylpropyl, 3-methylbutyl, neopentyl, 1,1-dimethylpropyl, 2-methylpentyl, 3-ethylpentyl, 1,3-dimethylbutyl, 2-propylpentyl, 1-ethyl-1,2-dimethylpropyl, 1-methylpentyl, 4-methylpentyl, 4-methyl branched alkyl groups such as 1-methylhexyl, 5-methylhexyl, 2-ethylhexyl, 1-methylhexyl, 1-ethylpentyl, 1-propylbutyl, 3-ethylheptyl, 2,2-dimethylheptyl, 1-methylheptyl, 1-ethylhexyl, 1-propylpentyl, 1-methyloctyl, 1-ethylheptyl, 1-propylhexyl, 1-butylpentyl, 1-methylnonyl, 1-ethyloctyl, 1-propylheptyl, and 1-butylhexyl; Cyclopropyl, 1-methylcyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, 1-methylcyclohexyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 1,2-dimethylcyclohexyl, 1,3-dimethylcyclohexyl, 1,4-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethyl Examples of cycloalkyl groups include cyclooctyl, 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 alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 4 carbon atoms.

[0027] Of 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 is preferably an alkyl group having 1 to 10 carbon atoms, and R 4 is preferably a hydrogen atom.

[0029] The l, m, and n are the ratios of the following copolymer components (L), (M), and (N) contained in one molecule, and are values ​​(ratios) of the average number of each component contained in one molecule, rounded to one decimal place and expressed as an integer. The ratio and average number of each component contained in one molecule are 1 H-NMR analysis and 13 This was determined by C-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 1 to 1000, preferably 2 to 800, more preferably 5 to 600, and even more preferably 10 to 400. l is 0 to 1000, preferably 1 to 700, more preferably 2 to 400, and further preferably 5 to 100.

[0031] The compound represented by formula (III) may be a random copolymer in which the 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) forms a block, but is preferably a random copolymer. The polyester resin of the present invention may be one or more kinds of polyester resins as long as the above m, n, and l are satisfied.

[0032] The compound represented by formula (III) can be prepared in a 2-gallon free radical continuous polymerization reactor system by referring to the descriptions in, for example, Patent Documents 1 to 3, U.S. Patent Application Nos. 09 / 354,350 and 09 / 614,402, etc., and further, an epoxy group-modified compound is used.

[0033] The content of the compound represented by formula (III) is 0.0002 to 5.9 wt %, preferably 0.0005 to 5.0 wt %, more preferably 0.001 to 4.5 wt %, even more preferably 4.0 wt % or less, and particularly preferably 3.5 wt % or less, based on 100 wt % of the alcohol component that constitutes the polyester resin. If the content of the compound represented by formula (III) is less than 0.0002% by weight, drawdown occurs during molding, resulting in unstable molding, or even if molding is possible, the molded product tends to have uneven thickness. On the other hand, if the content of the compound represented by formula (III) exceeds 5.9% by weight, gelation occurs, melt fracture occurs during molding, the surface smoothness is poor, and the molded product tends to be devitrified. In addition, the molded product tends to contain gel and have low quality.

[0034] The compound represented by formula (III) may have a predetermined weight-average molecular weight, and the weight-average molecular weight of the compound represented by formula (III) is preferably 330 or more and 500,000 or less, more preferably 500 or more, even more preferably 700 or more, still more preferably 1,000 or more, more preferably 300,000 or less, even more preferably 100,000 or less, and still more preferably 50,000 or less. If the weight-average molecular weight of the compound represented by formula (III) is less than 330, the unreacted compound may bleed out onto the surface of the molded article, possibly contaminating the surface of the molded article. On the other hand, if the weight-average molecular weight of the compound represented by formula (III) is more than 500,000, the compatibility between the compound and the polyester may be poor when a molded article made of a polyester resin is bent, which may result in the generation of voids and whitening. The weight average molecular weight can be determined, for example, by GPC based on standard polystyrene conversion. Specifically, the weight-average molecular weight can be determined by weighing 4 mg of a sample of the compound represented by formula (III), dissolving it in 4 ml of a mixed solvent of chloroform and isofluoroisopropanol (60 / 40% by volume), filtering the solution through a 0.2 μm membrane filter, subjecting the resulting sample solution to GPC, and converting it into standard polystyrene.

[0035] The dicarboxylic acid component and the diol component used in the present invention are as follows.

[0036] Examples of the dicarboxylic acid component include saturated aliphatic dicarboxylic acids 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, and dimer acid, or ester-forming derivatives thereof (e.g., alkyl esters of these having 1 to 20 carbon atoms), and unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, and itaconic acid, or ester-forming derivatives thereof (e.g., Examples of aromatic dicarboxylic acids include aromatic dicarboxylic acids exemplified by aromatic dicarboxylic acids such as alkyl esters having 1 to 20 carbon atoms (e.g., alkyl esters thereof 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'-biphenylsulfonedicarboxylic acid, 4,4'-biphenyletherdicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, pamoic acid, and anthracenedicarboxylic acid, as well as ester-forming derivatives thereof (e.g., alkyl esters thereof having 1 to 20 carbon atoms, preferably dimethyl terephthalate).

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

[0038] In addition to the above dicarboxylic acids, a small amount of a tricarboxylic or tetracarboxylic acid may be used. Examples of the carboxylic acid include ethanoic acid, tricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3',4'-biphenyltetracarboxylic acid, and ester-forming derivatives thereof (for example, alkyl esters of these having 1 to 20 carbon atoms).

[0039] As the alcohol component, a diol component is used together with the compound represented by formula (III). In 100% by weight of the alcohol component, the diol component (not including the compound represented by formula (III)) preferably accounts for 99.9998 to 94.1% by weight, 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, and the ethylene glycol content is preferably 85 mol % or more, and more preferably 85 to 99 mol %, of 100 mol % of the diol component. Examples of diols that may be used other than ethylene glycol 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 (having four or more ethylene structural units), polytrimethylene glycol, polytetramethylene glycol, aliphatic glycols such as fluorenediol, hydroquinone, 4,4'-dihydroxybis(2-methyl-2-propanol), and the like. Examples of the 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, and glycols obtained by adding ethylene oxide to these glycols, and products obtained by adding water to bisphenol A, F, S, or C.

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

[0041] Examples of the alcohol include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, and hexanetriol.

[0042] Examples of the hydroxycarboxylic acid 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, and ester-forming derivatives thereof (for example, alkyl esters of these having from 1 to 20 carbon atoms).

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

[0044] The polyester resin of the present invention preferably contains 85 to 100 mol % of terephthalic acid in 100 mol % of the dicarboxylic acid component, and ethylene glycol as the alcohol component (more precisely, the diol component). The content of ethylene glycol is preferably 85 to 99 mol % in 100 mol % of the diol component. Terephthalic acid is contained in 100 mol % of the dicarboxylic acid component, more preferably 90 to 100 mol %, and even more preferably 95 to 100 mol %, and ethylene glycol is contained in 100 mol % of the diol component, more preferably 90 to 99 mol %, and even more preferably 95 to 99 mol %. 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 and has a branched structure. The increased molecular weight has a "melt strength enhancing effect" that can improve processability such as moldability. At the same time, the melt viscosity and melt tension can be adjusted, which can improve the resistance to whitening on bending of molded articles and suppress the bleeding of unreacted substances onto the surface of molded articles. If the content of terephthalic acid and ethylene glycol is outside the above range, the polyester resin will become amorphous, and it will be impossible to increase the viscosity by solid-state polymerization, which may make it impossible to obtain a molded product with high mechanical properties.

[0046] Furthermore, the polyester resin of the present invention preferably has a reduced cyclic oligomer content. The cyclic oligomer is preferably a tetramer, more preferably a tetramer formed by the reaction of terephthalic acid and ethylene glycol (hereinafter also referred to as CT4), i.e., a cyclic tetramer in which terephthalic acid, ethylene glycol, terephthalic acid, ethylene glycol, terephthalic acid, ethylene glycol, terephthalic acid, and ethylene glycol are bonded in this order in a ring. The content of cyclic oligomer tetramer in the polyester resin is preferably less than 2680 ppm, more preferably 2650 ppm or less, even more preferably 2600 ppm or less, and preferably more than 0 ppm, more preferably 1 ppm or more, even more preferably 10 ppm or more, and still more preferably 100 ppm or more. By keeping free CT4 levels below 2680 ppm, bleed-out to the surface of molded products can be suppressed, improving the transparency of molded products and films and maintaining their high quality. Furthermore, sufficient transparency can be maintained even in thick molded products and films. Furthermore, when CT4 levels exceed 2680 ppm, there is a tendency for the area around the resin outlet of the extrusion die and the mold of the injection molding machine to become very dirty during continuous film formation and fiber extrusion. Furthermore, free CT4 that bleeds out to the surface of molded products tends to adhere to the surfaces of films, molded products, and fibers, reducing their commercial value. Although the mechanism behind these effects is unclear, it is thought that the polyester contains a dicarboxylic acid component and an alcohol component, and the content of the compound represented by formula (III) is 0.0002 to 5.9 wt % in 100 wt % of the alcohol component, so that the structure of formula (III) acts as a steric hindrance during ring formation of CT4, resulting in free CT4 being 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 by dissolving the polyester resin in a mixed solvent of parachlorophenol / tetrachloroethane (3 / 1: weight ratio) and using an Ostwald viscometer at 30°C.

[0048] The acid value (AV) of the polyester resin used in the present invention is preferably 100 eq / 10 6 g (ton) or less, preferably 60eq / 10 6 g or less, more preferably 50eq / 10 6 g or less. On the other hand, the lower the lower limit, the better. 6 The closer to 100eq / 10g the better. 6 If it exceeds 1000 g, gel tends to occur, and the surface smoothness and haze tend to deteriorate. The acid value can be determined by dissolving a polyester resin sample in an alcohol and / or ether solution and titrating it with an alcoholic sodium hydroxide solution or an alcoholic potassium hydroxide solution using a phenolphthalein reagent as an indicator. A specific method for measuring the acid value is as shown in the Examples.

[0049] The polyester resin of the present invention may have a predetermined melting point, and the melting point of the polyester resin 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 measured using a differential scanning calorimeter (DSC) at a temperature increase rate of 20°C / min up to 300°C, and the maximum peak temperature of the heat of fusion can be determined as the crystalline melting point.

[0050] The polyester resin of the present invention is preferably produced using a polymerization catalyst containing at least an aluminum compound and a phosphorus compound, and preferably has an aluminum content of 3 to 1,000 ppm and a phosphorus content of 5 to 10,000 ppm derived from the polymerization catalyst. As other polymerization catalysts, one or more compounds selected from titanium compounds and germanium compounds may be used, or a combination of a phosphorus compound and a germanium compound 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, in terms of aluminum atoms, relative to the total mass of the polyester resin is preferably 3 to 1000 ppm, more preferably 5 to 800 ppm, and even more preferably 8 to 500 ppm. If the amount of aluminum is too small, the polymerization activity may decrease, while if the amount of aluminum is too large, a large amount of aluminum-derived foreign matter may be generated.

[0052] The phosphorus compound used together with the aluminum compound as a polymerization catalyst will be described below. 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 in the same molecule, more preferably is at least one selected from a phosphonic acid compound and a phosphinic acid compound having a phenol structure in the same molecule, and even more preferably is a phosphonic acid compound having a phenol structure in the same molecule.

[0054] Examples of phosphorus compounds having a phenol structure in the same molecule include p-hydroxyphenylphosphonic acid, dimethyl p-hydroxyphenylphosphonate, diethyl p-hydroxyphenylphosphonate, diphenyl p-hydroxyphenylphosphonate, bis(p-hydroxyphenyl)phosphinic acid, methyl bis(p-hydroxyphenyl)phosphinate, phenyl bis(p-hydroxyphenyl)phosphinate, p-hydroxyphenylphenylphosphinic acid, methyl p-hydroxyphenylphenylphosphinate, phenyl p-hydroxyphenylphenylphosphinate, p-hydroxyphenylphosphinic acid, methyl p-hydroxyphenylphosphinate, phenyl p-hydroxyphenylphosphinate, and diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate.

[0055] Among them, the phosphorus compound is particularly preferably 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid diethyl ester, such as Irgamod (registered trademark) 295 (manufactured by BASF).

[0056] The amount of phosphorus is preferably 5 to 10,000 ppm, more preferably 8 to 8,000 ppm, and even more preferably 10 to 6,000 ppm, in terms of phosphorus atoms, relative to the total mass of the polyester resin. If the amount of phosphorus is too small, the polymerization activity may decrease and a large amount of foreign matter derived from aluminum may be generated, whereas if the amount of phosphorus is too large, the catalyst cost may increase.

[0057] Titanium compounds include tetrabutyltitanium, tetrabenzyltitanate, tetra-n-propyltitanate, tetraisopropyltitanate, tetra-n-butyltitanate, tetraisobutyltitanate, tetra-tert-butyltitanate, tetracyclohexyltitanate, tetraphenyltitanate, tetrabenzyltitanate, lithium oxalate titanate, potassium oxalate titanate, ammonium oxalate titanate, titanium oxide, composite oxides of titanium with silicon, zirconium, alkali metals, alkaline earth metals, etc., titanium orthoesters or condensed orthoesters, titanium orthoesters or Examples of the reactive species include reaction products of condensed orthoesters and hydroxycarboxylic acids, reaction products of titanium orthoesters or condensed orthoesters, hydroxycarboxylic acids, and phosphorus compounds, and reaction products of titanium orthoesters or condensed orthoesters, polyhydric alcohols having at least two hydroxyl groups, 2-hydroxycarboxylic acids, and bases. Of these, tetrabutyltitanium, composite oxides of titanium and silicon, composite oxides of titanium and magnesium, and reaction products of titanium orthoesters or condensed orthoesters, hydroxycarboxylic acids, and phosphorus compounds 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 in terms of titanium atoms relative to the total mass of the polyester resin. Examples of germanium compounds include germanium dioxide and germanium acetate, with germanium dioxide being 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 in terms of germanium atoms relative to the total mass of the polyester resin. The amounts of the above atoms may be calculated by, for example, X-ray fluorescence analysis.

[0058] Furthermore, as the phosphorus compound to be used together with the germanium compound, phosphoric acid and phosphate esters such as trimethyl phosphate, triethyl phosphate, phenyl phosphate, and triphenyl phosphate; phosphorous acid and phosphite 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 the melt tension decreases as the temperature increases above 250°C. In the present invention, from the viewpoint of exhibiting performance equal to or better than that of high density polyethylene, the melt tension is set to a temperature of 270°C, a take-up speed of 100 m / min, and a shear rate of 243 s -1 The melt tension is preferably 14 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, by using a capillary rheometer under specified conditions (capillary length 10 mm, capillary diameter 1 mm, temperature 270°C, shear rate 243 s -1 The value can be calculated by using a maximum take-up speed of 200 m / min, a take-up start speed of 10 m / min, or a take-up speed of 100 m / min (constant), and a take-up time of 90 seconds.

[0061] The polyester resin of the present invention has a shear rate of 2000 s when melted. -1 The higher the temperature is above 250°C, the lower the melt viscosity becomes. In the present invention, from the viewpoint of suppressing the occurrence of melt fracture during melt extrusion, the melt viscosity is set to 270°C at a shear rate of 30 s -1 26000 dPa·s or more, temperature 270℃, shear rate 2000 s -1The polyester resin of the present invention exhibits thixotropy at high temperatures during melting, and is therefore able to suppress the occurrence of melt fracture, resulting in good moldability.

[0062] Melt viscosity is measured at a temperature of 270°C and a shear rate of 30 s -1 The melt viscosity is preferably 26,000 dPa·s or more, more preferably 28,000 dPa·s or more, and even more preferably 30,000 dPa·s or more, and 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 is measured at a temperature of 270°C and a shear rate of 2000 s -1 The melt 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, based on JIS K7199. The melt viscosity is measured, for example, by using a capillary rheometer under specified conditions (capillary length 10 mm, capillary diameter 1 mm, temperature 270 °C, shear rate 30 s -1 or 2000s -1 ) can be used to find the

[0065] From the viewpoint of heat resistance, the polyester resin of the present invention may have a predetermined thermal oxidative decomposition parameter (TOD), and the thermal oxidative decomposition parameter (TOD) of the polyester resin is preferably 0.390 or less. The TOD can be calculated by the method described in the Examples section below. The 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 the TOD is, for example, 0.010 or more, 0.015 or more, or 0.020 or more. If the TOD exceeds 0.390, moldability during drawdown may be reduced.

[0066] The polyester resin of the present invention may contain additives such as organic, inorganic, and organometallic toners, as well as fluorescent brighteners. By incorporating one or more of these additives, discoloration, such as yellowing, of the polyester resin can be suppressed to an even greater level. The polyester resin may also contain other optional polymers, antistatic agents, antifoaming agents, dyeability improvers, dyes, pigments, matting agents, fluorescent brighteners, stabilizers, antioxidants, and other additives. Examples of antioxidants that can be used include aromatic amine-based and phenol-based antioxidants, and examples of stabilizers that can be used include phosphorus-based, sulfur-based, and amine-based stabilizers, such as phosphoric acid and phosphate ester-based stabilizers.

[0067] The polyester resin can be directly introduced into a molding process to form a molded article either in the molten state after the melt polycondensation process has been completed as described above, or in chip form after further treatment such as solid-state polymerization has been completed. Alternatively, a predetermined amount of additives, such as a crystallization property improver, aldehyde reducer, coloring improver, stabilizer, etc., can be added to any reactor or transport pipe in the melt polycondensation polymer production process, and the resulting mixture can be melt polycondensed to have the desired properties, and then introduced into a molding process either as is or after further treatment such as solid-state polymerization has been completed to form a molded article.

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

[0069] 2. Polyester resin manufacturing method The polyester resin of the present invention can be produced by a conventional method. For example, when producing PET, it can be produced by a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components, followed by distillation of water, followed by esterification, followed by polycondensation under reduced pressure. Alternatively, it can be produced by a transesterification method in which dimethyl terephthalate is reacted with ethylene glycol and, if necessary, other copolymerization components, followed by distillation of methyl alcohol, followed by transesterification, followed by polycondensation under reduced pressure. Furthermore, solid-state polymerization may be performed as needed to increase the intrinsic viscosity. To promote crystallization before solid-state polymerization, the molten polymerized polyester may be allowed to absorb moisture and then heated for crystallization, or water vapor may be directly sprayed onto polyester chips for crystallization. The compound represented by formula (III) is preferably added during polymerization. The compound represented by formula (III) may be added in a dispersed state.

[0070] The polycondensation reaction may be carried out in a batch reactor or a continuous reactor. In either of these systems, the esterification reaction or transesterification reaction may be carried out in one stage or in multiple stages. The polycondensation reaction may be carried out in one stage or in multiple stages. The solid-state polymerization reaction, like the polycondensation reaction, can be carried out in a batch reactor or a continuous reactor. The polycondensation and solid-state polymerization may be carried out continuously or in separate stages. An example of a preferred continuous production method will be described below, taking PET as an example of polyester resin.

[0071] The esterification reaction is carried out using a multistage apparatus in which one to three esterification reactors are connected in series, under conditions where ethylene glycol is refluxed, while water or alcohol produced by the reaction is removed 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 / cm. 2 G, more preferably 0.5 to 2 kg / cm 2The temperature of the final stage esterification reaction is usually 250 to 290°C, preferably 255 to 275°C, and the pressure is usually 0 to 1.5 kg / cm 2 G, preferably 0 to 1.3 kg / cm 2 G. When the process is carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stages are conditions between the reaction conditions for the first stage and the reaction conditions for the final stage. It is preferable that the increase in the reaction rate of these esterification reactions is smoothly distributed among the respective stages. It is desirable that the final esterification reaction rate reaches preferably 90% or more, more preferably 93% or more. These esterification reactions yield low-order condensates with a molecular weight of about 500 to 5,000.

[0072] When terephthalic acid is used as the raw material, the esterification reaction 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 coexistence of a polycondensation catalyst.

[0073] Furthermore, polycondensation is preferably carried out by adding a small amount of a tertiary amine such as triethylamine, tri-n-butylamine, or benzyldimethylamine; a quaternary ammonium hydroxide such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, or trimethylbenzylammonium hydroxide; or a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate, or sodium acetate, since 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 based on the total diol components).

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

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

[0076] The resulting low-order condensate is then supplied to a multi-stage liquid-phase polycondensation process. Regarding polycondensation reaction conditions, the reaction temperature for the first stage polycondensation is preferably 250 to 290°C, more preferably 260 to 280°C, and the pressure is preferably 500 to 20 Torr, more preferably 200 to 30 Torr. The reaction temperature for the final stage polycondensation is preferably 265 to 300°C, more preferably 275 to 295°C, and the pressure is preferably 10 to 0.1 Torr, more preferably 5 to 0.5 Torr. When the process is carried out in three or more stages, the reaction conditions for the intermediate stage polycondensation reactions are intermediate between the reaction conditions for the first stage and the reaction conditions for the final stage. It is preferable that the rate of increase in intrinsic viscosity achieved in each of these polycondensation reaction processes is smooth.

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

[0078] The catalyst used in the present invention has catalytic activity not only in polycondensation reactions but also in esterification reactions and transesterification reactions. For example, the catalyst can be used in the transesterification reaction between an alkyl ester of a dicarboxylic acid, such as dimethyl terephthalate, and a glycol, such as ethylene glycol. Furthermore, the catalyst used in the present invention has 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 the present invention can be added to the reaction system at any stage of the polymerization reaction. For example, it can be added to the reaction system 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 the polymerization catalyst other than the phosphorus compound used in the present invention is not particularly limited, and may be in powder or neat form, or in the form of a slurry or solution in a solvent such as ethylene glycol. Furthermore, aluminum or an aluminum compound or a phosphorus compound may be added as a premixed mixture with other components, or these may be added separately. Furthermore, aluminum or an aluminum compound or a phosphorus compound and other components may be added to the polymerization system at the same time, or each component may be added at a different time. Furthermore, the entire amount of the catalyst may be added at once, or may be added 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-state polymerization. In the blow molding of a heat-resistant bottle, a bottomed precursor generally called a preform is prepared, and this preform may be blown and stretched in a mold and then heat-set. Methods such as compression molding and injection molding are used to manufacture the preform. For example, in injection molding, a preform can be obtained by heating and melting the resin to 260 to 350°C and injecting it into a preform mold. Typically, the preform has a thick-walled test tube shape with a gate at the bottom and a cap screw engraved on the mouth.

[0082] In the case of a heat-resistant bottle, the mouth of the obtained preform may be crystallized. Crystallization can prevent deformation of the mouth even when hot contents are filled. Crystallization of the mouth is preferably carried out by heating to 130 to 200°C, more preferably 140 to 190°C. Heating methods that can be used include infrared heaters, hot air, induction heating, and immersion in an oil bath, with the use of infrared heaters being preferred from the viewpoint of productivity. Heat crystallization of the mouth may also be carried out after blow molding.

[0083] The preform is heated and stretched in the length direction (vertical direction) of the bottle while being blow-molded in the circumferential direction to obtain a bottle. Stretching in the length direction is usually performed with a rod-shaped stretching rod, and pressurized gas such as air or nitrogen is used in the circumferential direction. The pressurized gas is preferably 1 to 10 MPa. A method in which pressurized gas is blown in while inserting a stretching rod to simultaneously stretch the length direction and the circumferential direction is preferred, but stretching in the length direction can also be performed first and then in the circumferential direction. Heating can be performed with an infrared heater, hot air, induction heating, or the like. The heating temperature is usually 80 to 130°C, preferably 90 to 120°C.

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

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

[0086] When heat setting is performed in the same mold subsequent to blow molding, the lower limit of the mold temperature for blow molding 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 range, crystallization may not be sufficiently promoted in the subsequent heat setting, resulting in insufficient heat resistance, or a longer heat setting time may be required, resulting in reduced 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 the melt tension decreases as the temperature increases during melting. Therefore, when the mold temperature is increased, the melt tension decreases upon contact between the mold and the polyester resin, thereby reducing the occurrence of melt fracture, while after extrusion from the mold, the melt tension increases, thereby reducing the occurrence of drawdown.

[0088] The blow-molded bottle is subsequently 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 the heat-set time is less than this, crystallization may not be sufficiently promoted, 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. A long heat-set time not only reduces productivity, but also requires the use of many molds in the case of a rotary blow molding machine, which can be economical if the equipment becomes large. After heat-setting in the mold, additional heat-setting may be performed by heating with infrared rays, hot air, induction heating, etc.

[0089] It is also possible to carry out blow molding in a mold at 5 to 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 case.

[0090] The blow molding device may be equipped with one mold, but for mass production, it is preferable to use a system that has multiple molds and these molds move sequentially to the following locations: a location where the heated preform is set in the mold, a location where it is stretched, a location where it is heat-set, and a location where the bottle is ejected. Although the cold parison method in which a cooled preform is reheated has been described above, a hot parison method in which blow molding is performed without completely cooling the preform is also possible.

[0091] The internal volume of the molded bottle is preferably 200 ml to 6 L, and more preferably 300 ml to 2 L. The shape of the bottle body can be any shape, such as circular, rectangular (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 (for example, bottles) for cosmetics, detergents, beverages, etc.

[0093] This application claims the benefit of priority to Japanese Patent Application No. 2020-207929, filed on December 15, 2020. The entire content of the specification of Japanese Patent Application No. 2020-207929, filed on December 15, 2020, is incorporated herein by reference. [Example]

[0094] The present invention will be specifically explained below by showing examples, but the present invention is not limited to these examples.

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

[0096] Determination of polyester resin composition The composition of the polyester resin was determined in deuterated chloroform using a RUKER AVANCE NEO600 Fourier transform nuclear magnetic resonance spectrometer. 1 H-NMR analysis and 13 C-NMR analysis was performed and the ratio was determined from 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. Measurements were performed using a differential scanning calorimeter (DSC) DSC-Q100 manufactured by TA Instruments Japan, Inc., at a heating rate of 20°C / min up to 300°C, 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: weight ratio) were placed in a round-bottom flask equipped with a stirrer, and the pellets were dissolved in the mixed solution by stirring at 100-105°C for 2 hours. The solution was allowed to cool to room temperature, and foreign matter was filtered out using a polytetrafluoroethylene membrane filter (PTFE membrane filter manufactured by Advantec, product name: T100A047A) with a diameter of 47 mm and a pore size of 1.0 μm under a pressure of 0.15 MPa. The effective filtration diameter was 37.5 mm. After filtration, the filter 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 under an optical microscope to determine the presence or absence of undissolved matter (gel).

[0099] Melt tension measurement During molding of the polyester resin, the melt tension was measured using the following equipment and conditions. Capillary rheometer (Toyo Seiki Seisakusho) Temperature: 270℃ Capillary length: 10 mm Capillary diameter: 1 mm Shear rate: 243 s -1 Maximum take-up speed: 200m / min Take-up start speed: 10m / min Or take-up speed: 100m / min (constant) Pick-up time: 90 seconds

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

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

[0102] Measurement of the amount of aluminum atoms, phosphorus atoms, and germanium atoms in polyester resin Polyester resin was heated to its melting point +20°C in a stainless steel circular ring with a thickness of 5 mm and an inner diameter of 50 mm to melt it, and a sample piece was prepared. The amount of elements was determined by fluorescent X-ray analysis and expressed in ppm. When determining the amount, a calibration curve obtained in advance from samples with known amounts of each element was used.

[0103] Profile extrusion molding (evaluation of moldability (drawdown), mechanical properties, surface smoothness, and transparency) The polyester resin cylinder temperature was set to 270°C, and a die lip was attached to a single-screw extruder (L / D = 30, full-flight screw, screw diameter 50 mm). A sizing die, which determines the final dimensions of the extruded profile, was then attached to the end of a cooling water bath. The extruded profile was then passed through the water bath and molded into a profile extrusion molding machine equipped with a take-off machine. The drawdown during molding, as well as the mechanical properties, surface smoothness, and transparency of the molded product, were evaluated according to the following criteria. The results are shown in Table 2.

[0104] Formability (drawdown) evaluation The drawdown was evaluated according to the following criteria. ◎: No sagging of polyester resin occurs during molding, and the shape is maintained. ○: Slight sagging of polyester resin occurs during molding △: Polyester resin drips during molding, making stable mass production impossible ×: The polyester resin dripped during molding, preventing the resin from passing through the die lip into the sizing mold.

[0105] Evaluation of mechanical properties (strength) of molded products The polyester resin molded product was bent 180° and evaluated according to the following criteria. ○: No cracks ×: Cracks present

[0106] Surface smoothness evaluation The outer surface irregularities of polyester resin molded products were measured using a Surfcorder Et4000A manufactured by Kosaka Laboratory, and the three-dimensional roughness was compared based on the center plane average (SRa) according to the following criteria. ◎: 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 more

[0107] Transparency Assessment The polyester resin molded product was cut into a 3 cm square, and the haze was measured using a haze meter NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd., and evaluated according to the following criteria. ◎: Haze less than 5% ○: Haze is 5% or more but less than 10% ×: Haze is 10% or more

[0108] Evaluation of heat resistance (thermo-oxidative stability parameter (TOD)) Polyester resin chips ([IV] i ) was freeze-ground to 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. Next, a drying tube containing silica gel was attached to the top of the test tube, which was then immersed in a nitrate bath at 230°C under dry air and heated for 15 minutes. [IV] f1 The TOD was calculated as follows, where [IV] i and [IV] f1The values ​​indicate the IV (dL / g) before and after the heating test, respectively. Freeze-grinding was performed using a freezer mill (Model 6750, manufactured by Specs, USA). Approximately 2 g of resin chips and a dedicated impactor were placed in a dedicated cell, and the cell was then set in the device, which was filled with liquid nitrogen and held for approximately 10 minutes. The device was then crushed for 5 minutes at RATE 10 (the impactor moved back and forth approximately 20 times per second). TOD=0.245{[IV] f1 -1.47 -[IV] i -1.47} The smaller the TOD value of a polyester resin, the higher its 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 then diluted with 4 ml of chloroform. 10 ml of methanol was added to this to precipitate the polyester resin, which was then centrifuged. The supernatant after centrifugation was concentrated to dryness and redissolved in 0.4 ml of dimethylformamide. The CT4 content was measured by high-performance liquid chromatography. Instrument: Waters ACQUITY UPLC Column: Waters BEH-C18 2.1 x 150 mm (Waters)

[0110] Evaluation of transparency during continuous molding The dried polyester resin was fed into an extruder equipped with a sheet die and continuously molded into a sheet approximately 0.5 mm thick at 280°C for 2 days. The state of contamination at the die exit and the condition of the sheet surface were evaluated visually according to the following criteria. (Evaluation criteria) ◎: Almost no dirt adhered to the die exit, and the sheet surface is in good condition ○: There is a small amount of dirt adhering to the die exit, but the sheet surface is in good condition △: There is a little dirt on the die exit and a little foreign matter on the sheet surface ×: The adhesion of dirt to the die exit is very severe, and there is a lot of adhesion on the sheet surface

[0111] Synthesis Examples 1 to 6 (Preparation of Compounds Represented by Formula (III) (Branching Agents)) The compounds represented by formula (III) were prepared in a 2-gallon free radical continuous polymerization reactor system with reference to the descriptions in Patent Documents 1 to 3, U.S. Patent Application Nos. 09 / 354,350 and 09 / 614,402. The compositions of the compounds represented by formula (III) obtained in Synthesis Examples 1 to 6 are shown in Table 1 below. The weight-average molecular weight of the compound represented by formula (III) was calculated by GPC in terms of standard polystyrene. Specifically, 4 mg of a sample of the compound represented by formula (III) was weighed and dissolved in 4 ml of a mixed solvent of chloroform and isofluoroisopropanol (60 / 40 volume %), and then filtered through a 0.2 μm membrane filter. The resulting sample solution was measured by GPC and the weight-average molecular weight was calculated in terms of standard polystyrene.

[0112] In addition, l, m, and n of the compound represented by formula (III) are 1 H-NMR, and 13 It was determined by C-NMR analysis. That is, l, m, and n are expressed as integers by rounding off the first decimal place as the average number. 1 For H-NMR, deuterated chloroform / trifluoroacetic acid mixed solvent (volume ratio 85 / 15) was used. 13 For C-NMR, the sample was dissolved in deuterated chloroform or a mixed solvent of deuterated chloroform and hexafluoroisopropanol (volume ratio 1 / 1), and then measured with a Fourier transform nuclear magnetic resonance spectrometer (BRUKER AVANCE NEO600) for 50 to 200 cycles ( 1 H-NMR), 10,000 times ( 13 C-NMR) conditions were measured at room temperature. 1 H-NMR and 13 The ratio of each component and the proportion of components located at the terminals were calculated from the C-NMR spectrum, and l, m, and n were determined.

[0113] In addition, the compound represented by formula (III) used in the synthesis example has the following methacrylic monomer structural unit (hereinafter abbreviated as DEMA-DE structural unit) (* represents a bond with other monomer structural units (for example, styrene structural unit, methyl methacrylate structural unit)). For example, a compound containing this DEMA-DE structural unit can be obtained by a method of subjecting glycidyl methacrylate to a ring-opening reaction with water and adding a diol (ethylene glycol), or a method of subjecting glycidyl methacrylate to an addition reaction with a diol. 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, a compound represented by formula (III) may be obtained by a method of subjecting it to a ring-opening reaction with water and adding a diol (ethylene glycol).

[0114] <DEMA-DE structural unit>

Chemical formula

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

[0116]

Table 1

[0117] Example 1 A 10-liter pressure vessel equipped with a stirrer, thermometer, and outflow cooler was charged with 2593 g of terephthalic acid (Mitsui Chemicals), 1937 g of ethylene glycol (Nippon Shokubai), and 4 g of triethylamine (Nacalai Tesque), and 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 (III) obtained in Synthesis Example 1 was added continuously while controlling the flow rate so that the amount was 0.2 wt% relative to 100 wt% of the alcohol component of the resulting polyester resin, and the reaction was allowed to proceed in stages.

[0118] Aluminum acetate was added as a polycondensation catalyst to the polyester resin to give 30 ppm aluminum (Al) and 72 ppm phosphorus (P) based on the mass of the polyester resin. Solvent Blue 45 (Clariant) was then added to the polyester resin to give 1 ppm. The mixture was stirred at 260°C under a nitrogen atmosphere at atmospheric pressure for 5 minutes. The temperature was then raised to 280°C over 60 minutes, while the pressure in the reaction system was gradually reduced to 13.3 Pa (0.1 Torr). The polycondensation reaction was then 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 extruded into cold water in the form of strands for quenching. The resin was then held in cold water for 20 seconds and then cut into cylindrical polyester pellets with a length of approximately 3 mm and a diameter of approximately 2 mm.

[0119] The polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80°C, 12 hours), followed by crystallization (13.3 Pa or less, 130°C, 3 hours, then 13.3 Pa or less, 160°C, 3 hours). After cooling, the polyester pellets were subjected to solid-state polymerization in a solid-state polymerization reactor while maintaining the system pressure at 13.3 Pa or less and 200 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 the compound represented by formula (III) 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 having an intrinsic viscosity IV of 1.17 dl / g and a TOD of 0.015.

[0121] Example 3 In Example 1, the amount of the compound represented by formula (III) obtained in Synthesis Example 1 was changed to 3.0 wt %, and polymerization was carried out under the same conditions as in Example 1 to obtain polyester pellets having 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 (III) obtained in Synthesis Example 1 was replaced with the compound represented by formula (III) obtained in Synthesis Example 2, and the amount added was changed to 0.2 wt %. Polymerization was carried out under the same conditions as in Example 1, and polyester pellets having an intrinsic viscosity IV of 1.20 dl / g and a TOD of 0.015 were obtained.

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

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

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

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

[0127] Example 9 A 10-liter pressure vessel equipped with a stirrer, thermometer, and outflow cooler was charged with 2593 g of terephthalic acid (Mitsui Chemicals), 1937 g of ethylene glycol (Nippon Shokubai), and 4 g of triethylamine (Nacalai Tesque), and 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 (III) obtained in Synthesis Example 1 was added continuously while controlling the flow rate so that the amount was 0.2 wt% relative to 100 wt% of the alcohol component of the resulting polyester resin, and the reaction was allowed to proceed in stages.

[0128] Germanium dioxide was added as a polycondensation catalyst to the polyester resin to achieve 100 ppm germanium atoms (Ge) and 50 ppm phosphorus atoms (P). Solvent Blue 45 (Clariant) was then added to the polyester resin to achieve 1 ppm. The mixture was stirred at 260°C under a nitrogen atmosphere and atmospheric pressure for 5 minutes. The temperature was then raised to 280°C over 60 minutes, while the pressure in the reaction system was gradually reduced to 13.3 Pa (0.1 Torr). The polycondensation reaction was then carried out at 280°C and 13.3 Pa. The pressure was then returned to atmospheric pressure with nitrogen, and the resin under slight pressure was extruded into cold water in the form of strands for quenching. The resin was then held in the cold water for 20 seconds and then cut into cylindrical polyester pellets approximately 3 mm long and 2 mm in diameter.

[0129] The polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80°C, 12 hours), followed by crystallization (13.3 Pa or less, 130°C, 3 hours, then 13.3 Pa or less, 160°C, 3 hours). After cooling, the polyester pellets were subjected to solid-state polymerization in a solid-state polymerization reactor while maintaining the system at 13.3 Pa or less and 200 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 (III), to obtain polyester pellets having an intrinsic viscosity IV of 1.19 dl / g and a TOD of 0.400.

[0131] Comparative Example 2 The amount of the compound represented by formula (III) 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 having 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 (III) 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 having an intrinsic viscosity IV of 0.71 dl / g and a TOD of 0.380.

[0133] [Table 2]

[0134] In Examples 1 to 9, the melt viscosity was measured at a temperature of 270°C and a shear rate of 30 s -1 26000 dPa·s or more, temperature 270℃, shear rate 2000 s -1 The strength was below 6500 dPa·s, and no gel was observed. [Industrial Applicability]

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

Claims

1. The polyester contains a dicarboxylic acid component and an alcohol component as its constituent components, The compound represented by formula (III) contains the following copolymer components (M), (N), and (L) as structural units, in which R 1 in the copolymer component (M) represents an aromatic hydrocarbon group having 6 to 20 carbon atoms, R 2 , R 3 , and R 4 in the copolymer components (N) and (L) each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, the numbers of the copolymer components (M), (N), and (L) are represented by m, n, and 1, respectively, and m and n each represent 1 to 1000 and 1 represents 0 to 1000, A polyester resin characterized in that the content of the compound represented by formula (III) is 0.001 to 3.5% by weight based on 100% by weight of the alcohol component. 【Chemistry 1】

2. 2. The polyester resin according to claim 1, wherein the weight average molecular weight of the compound represented by formula (III) is 330 or more and 500,000 or less.

3. 3. The polyester resin according to claim 1, wherein the dicarboxylic acid component comprises 85 to 100 mol % of terephthalic acid, and the dicarboxylic acid component comprises ethylene glycol as an alcohol component.

4. 4. The polyester resin according to claim 1, wherein the content of cyclic oligomer tetramer in the polyester resin is less than 2680 ppm.

5. Melt tension: temperature 270°C, take-up speed 100m / min, shear rate 243s -1 5. The polyester resin according to claim 1, wherein the strength is 14 mN or more.

6. Melt viscosity: Temperature: 270°C, shear rate: 30 s -1 26000 dPa·s or more, temperature 270 ° C, shear rate 2000 s -1 The polyester resin according to any one of claims 1 to 5, having a viscosity of 6500 dPa·s or less.

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