Polyester resin and method for producing the same

Abstract

To provide a polyester resin which is designed to reduce a cyclic oligomer content and has excellent transparency when made into a molded body.SOLUTION: A polyester resin includes terephthalic acid and ethylene glycol as a main component. In the polyester resin, a total content of an etherate of ethylene glycol in a total glycol component is 4.0-40.0 mol%, and a content of a cyclic oligomer is 0.7 mass% or less. An amount of a carboxyl end group is preferably 20.0 eq / t or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester resin and a method for producing the same. [Background technology]

[0002] Polyester resins, such as polyethylene terephthalate (PET), have excellent mechanical and chemical properties and are used in a wide range of fields, such as fibers for clothing and industrial materials, films or sheets for packaging and magnetic tapes, hollow molded products like bottles, casings for electrical and electronic components, and other engineering plastic molded products.

[0003] Polyethylene terephthalate can be obtained, for example, by polymerizing an esterified product mainly composed of terephthalic acid and ethylene glycol in the presence of a polycondensation catalyst. Polyesters produced in this way contain cyclic oligomers (cyclic dimers to cyclic decamers of ethylene terephthalate), which leads to a problem of reduced quality when used as fibers, molded articles, or films.

[0004] To solve the aforementioned problem, various methods have been considered. For example, in Patent Document 1, the formation of cyclic oligomers is suppressed by adding a metal derived from the polycondensation catalyst and other specific metal atoms during the esterification step or the melt polycondensation step. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-283393 [Overview of the project] [Problems that the invention aims to solve]

[0006] In Patent Document 1, the amount of cyclic oligomers in the resin is reduced, but upon remelting, the amount of cyclic oligomers increases, resulting in poor transparency when molded into a product. When used in fibers, it can cause uneven dyeing, and during processing, the oligomers can adhere to and accumulate on guides and heaters, leading to problems such as thread breakage. While it is possible to perform treatment to reduce the amount of cyclic oligomers after remelting, additional treatment is not desirable from a process perspective. Furthermore, in recent years, there has been a demand for polyester resins obtained without the use of metal catalysts in order to reduce environmental impact. The object of the present invention is to provide a polyester resin in which the amount of cyclic oligomers generated is suppressed, which exhibits excellent transparency when used as a molded article, and which suppresses uneven dyeing and fraying during processing when used as a fiber. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the present inventors have discovered a polyester resin containing terephthalic acid and ethylene glycol as its main components, which has a reduced amount of cyclic oligomers and excellent transparency when formed into a molded article, and have arrived at the present invention.

[0008] In other words, the gist of this invention is as follows:

[0009] (1) A polyester resin containing terephthalic acid and ethylene glycol as its main components, wherein the total content of ethylene glycol ethers in the total glycol components is 4.0 mol% or more, and the content of cyclic oligomers is 0.7% by mass or less. The sulfur content is 1 ~ 500 ppm Polyester resin. (2) The polyester resin of (1), wherein the amount of carboxyl terminal groups is 20.0 eq / t or more. (3) The polyester resin of (1) or (2), wherein the total content of cyclic oligomers and acyclic oligomers is 1.6% by mass or less. (4) Any of the polyester resins from (1) to (3) in which the diethylene glycol content is 2.5 mol% or more of the total glycol components. A polyester resin according to any one of (1) to (4), wherein the content of triethylene glycol is 0.1 to 5.5 mol% in all glycol components. A polyester resin according to any one of (1) to (5), wherein the content of tetraethylene glycol is more than 0.0 mol% and 2.0 mol% or less in all glycol components. A polyester resin according to any one of (1) to (6), wherein the total content of triethylene glycol and tetraethylene glycol is 7 mol% or less. ( 8 ) A polyester resin according to any one of (1) to ( 7 ), having a haze of 5% or less measured using a molded body with a thickness of 1 mm. ( 9 )(1) to ( 8 ) A molded body made of a polyester resin according to any one of. ( 10 )(1) to ( 8 ) A fiber made of a polyester resin according to any one of. ( 11 )(1) to ( 8 ) A film made of a polyester resin according to any one of. ( 12 )(1) to ( 8 ) A method for producing a polyester resin according to any one of, comprising a step of adding an organic sulfonic acid compound to the raw materials of the polyester resin and performing an etherification reaction of the glycol component. ( 13 ) The method for producing a polyester resin according to ( 12 ), wherein the organic sulfonic acid compound is one or more selected from 2-sulfobenzoic anhydride, o-sulfobenzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 5-sulfosalicylic acid, benzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, 5-sulfoisophthalic acid, and salts thereof.

Advantages of the Invention

[0010] The polyester resin of the present invention has a reduced amount of cyclic oligomers and exhibits excellent transparency when formed into a molded article. [Modes for carrying out the invention]

[0011] The polyester resin of the present invention will be described in detail below. The polyester resin of the present invention is a polyester resin mainly composed of terephthalic acid and ethylene glycol, and has a content of cyclic oligomers (cyclic dimers to cyclic decamers of ethylene terephthalate) of 0.7% by mass or less.

[0012] In the polyester resin of the present invention, the content of cyclic oligomers is 0.7% by mass or less, preferably 0.6% by mass or less, and more preferably 0.5% by mass or less. If the content of cyclic oligomers exceeds 0.7% by mass, the transparency of the molded article will be poor. The polyester resin of the present invention can have its cyclic oligomer content within the above range by using an organic sulfonic acid compound as a polymerization catalyst, as described later. In the present invention, a cyclic oligomer refers to a cyclic dimer to a cyclic decamer of ethylene terephthalate.

[0013] The total content of cyclic oligomers and acyclic oligomers (acyclic dimers to acyclic decamers of ethylene terephthalate) is preferably 1.6% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.3% by mass or less. Ethylene terephthalate oligomers include cyclic oligomers and acyclic oligomers. In the polyester resin of the present invention, by reducing the content of cyclic oligomers to a specific range as described above, the total content of cyclic and acyclic oligomers relative to the total oligomer content can be reduced, resulting in excellent transparency when molded.

[0014] The amount of carboxyl-terminal groups in the polyester resin of the present invention is preferably 20.0 eq / t or more, more preferably 25.0 eq / t or more, and even more preferably 30.0 eq / t or more. The upper limit of the amount of carboxyl-terminal groups is preferably 100.0 eq / t from the viewpoint of suppressing hydrolysis of the polyester resin.

[0015] <Glycol component> The polyester resin of the present invention contains ethylene glycol as the main component of the glycol component, as well as an etherified ethylene glycol (hereinafter sometimes simply referred to as "etherified ethylene glycol"). In this invention, "etherified product" refers to diethylene glycol, triethylene glycol, and tetraethylene glycol, and "total content of etherified product" refers to the total content of these products. The total content of etherified compounds in the glycol component is 4.0 mol% or more, preferably 5 to 40 mol%, more preferably 10 to 35 mol%, and even more preferably 15 to 30 mol%. If the total content of etherified compounds is less than 4.0 mol%, the content of cyclic oligomers cannot be kept below 0.7 mass%. Furthermore, if the total content of etherified compounds exceeds 40.0 mol%, thermal properties, weather resistance, and mechanical properties may deteriorate.

[0016] The polyester resin of the present invention contains a predetermined amount of etherified material as a glycol component, and the amount of cyclic oligomers is reduced, thereby enabling the production of molded articles with excellent transparency.

[0017] The polyester resin of the present invention has ethylene glycol as its main glycol component; more preferably, the content of ethylene glycol in the glycol component is 50 mol% or more, even more preferably 70 mol% or more, and particularly preferably 80 mol% or more. By having an ethylene glycol content of 50 mol% or more, a molded article with even better mechanical properties can be obtained.

[0018] The polyester resin of the present invention preferably has a diethylene glycol content of 2.5 mol% or more in the glycol component, more preferably 3.0 mol% or more, even more preferably 5.0 mol% or more, and particularly preferably 10 mol% or more. The polyester resin exhibits an improved reduction effect of cyclic oligomers when the diethylene glycol content is within the above range. From the viewpoint of mechanical properties, the upper limit of the diethylene glycol content in the glycol component is preferably 30 mol% or less.

[0019] The polyester resin of the present invention preferably has a triethylene glycol content of 0.1 to 5.5 mol%, and more preferably 0.2 to 4.0 mol%, in the glycol component. If the triethylene glycol content is less than 0.1 mol%, the reduction effect of cyclic oligomers may not be sufficiently obtained, while if it exceeds 5.5 mol%, the thermal properties and weather resistance may decrease.

[0020] Furthermore, the polyester resin of the present invention preferably has a total content of diethylene glycol and triethylene glycol in the glycol component of 2.6 mol% or more, more preferably 2.6 to 35 mol%, and even more preferably 3.2 to 34 mol%.

[0021] The polyester resin of the present invention preferably contains tetraethylene glycol as its glycol component, and more preferably has a tetraethylene glycol content of 2.0 mol% or less, and more preferably 0.1 to 0.5 mol%. If the tetraethylene glycol content in the glycol component of the polyester resin exceeds 2.0 mol%, the thermal properties and weather resistance may decrease.

[0022] The polyester resin of the present invention preferably has a total content of triethylene glycol and tetraethylene glycol in the glycol component of 7.0 mol% or less, more preferably 0.1 to 7.0 mol%, even more preferably 0.2 to 7.0 mol%, and particularly preferably 0.4 to 6.0 mol%. If the total content of triethylene glycol and tetraethylene glycol in the glycol component of the polyester resin exceeds 7.0 mol%, the mechanical properties may be inferior.

[0023] In the polyester resin of the present invention, a method for achieving the above-mentioned range for the content of cyclic oligomers and the total content of etherified products in the glycol component is, for example, a method for producing the polyester resin described later, which includes a step of carrying out an etherification reaction of ethylene glycol using an organic sulfonic acid compound as a polymerization catalyst.

[0024] The polyester resin of the present invention contains ethylene glycol and its etherified form as glycol components, but may also contain other glycol components. Specific examples include 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 3-methyl-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, and 1,10-deca. Examples of aromatic glycols include aliphatic glycols such as methylene glycol and 1,12-dodecanediol, hydroquinone, 4,4'-dihydroxybisphenol, 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 C, 2,5-naphthalenediol, and glycols obtained by adding ethylene oxide to these glycols. Among these, 1,3-propylene glycol, 1,4-butylene glycol, and 1,4-cyclohexanedimethanol are preferred.

[0025] <Dicarboxylic acid component> The polyester resin of the present invention contains terephthalic acid as the main component of the dicarboxylic acid component. The content of terephthalic acid in the dicarboxylic acid component is more preferably 50 mol% or more, even more preferably 70 mol% or more, and particularly preferably 80 mol% or more.

[0026] Examples of dicarboxylic acid components other than terephthalic acid 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, dimer acid, etc., or their ester-forming derivatives, and unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, itaconic acid, etc. Examples include carboxylic acids or their esterifying derivatives, orthophthalic acid, isophthalic acid, 5-(alkali metal) sulfisoisophthalic 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, and other aromatic dicarboxylic acids, or their esterifying derivatives, which may be used in combination. Among these, terephthalic acid and naphthalenedicarboxylic acid (especially 2,6-naphthalenedicarboxylic acid) are particularly noteworthy.

[0027] The polyester resin of the present invention may also contain polycarboxylic acid components other than the dicarboxylic acid component, as well as hydroxycarboxylic acid components.

[0028] <Polyhydric carboxylic acid components> Examples of polycarboxylic acid components other than the dicarboxylic acid components mentioned above include ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3′,4′-biphenyltetracarboxylic acid, or ester-forming derivatives thereof.

[0029] <Hydroxycarboxylic acid component> Examples of hydroxycarboxylic acid components 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, as well as cyclic esters such as ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide. Among these, the cyclic ester preferably contains ε-caprolactone, and is particularly preferably in an amount of 1.0 to 50.0 mol% of the polyester resin.

[0030] Examples of ester-forming derivatives of polycarboxylic acids and hydroxycarboxylic acids include their alkyl esters, acid chlorides, and acid anhydrides.

[0031] <Hayes> The polyester resin of the present invention, containing the above components, exhibits excellent transparency after molding. As an indicator of transparency, the haze measured using a molded article with a thickness of 1 mm is preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less.

[0032] <Mechanical properties> Furthermore, molded articles obtained from the polyester resin of the present invention containing the above components exhibit excellent mechanical properties such as tensile properties. As an indicator of these properties, the tensile elongation at break is preferably 70% or more, more preferably 100% or more, even more preferably 180% or more, and particularly preferably 200% or more.

[0033] <Intrinsic viscosity> The polyester resin of the present invention preferably has an intrinsic viscosity of 0.45 dl / g or more, more preferably 0.5 dl / g or more, and even more preferably 0.6 to 0.8 dl / g. If the intrinsic viscosity is less than 0.45 dl / g, sufficient mechanical properties may not be obtained when processed into a molded article.

[0034] <Additives> The polyester resin of the present invention may contain any polymer, antistatic agent, defoaming agent, dyeability improver, dye, pigment, matting agent, fluorescent whitening agent, stabilizer, antioxidant, colorant, flame retardant, or other additives, as long as they do not impair the effects of the present invention. Examples of antioxidants include aromatic amine-based and phenol-based antioxidants. Examples of stabilizers include phosphorus-based such as phosphoric acid or phosphate ester-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

[0035] The polyester resin of the present invention may contain organic, inorganic, or organometallic toners, or fluorescent whitening agents, etc., to the extent that they do not impair the effects of the present invention. This can further suppress discoloration such as yellowing of the polyester resin. Alternatively, to improve crystallinity, it may be mixed with other resins such as polyethylene, or inorganic nucleating agents such as talc.

[0036] The polyester resin of the present invention may have a cobalt compound added for purposes such as improving color tone, as long as it does not impair the effects of the present invention. The cobalt compound is not particularly limited, but examples include cobalt acetate, cobalt nitrate, cobalt chloride, cobalt acetylacetonate, cobalt naphthenate, and their hydrates. Among these, cobalt acetate tetrahydrate is particularly preferred. The amount of cobalt compound added is preferably 10 ppm or less, more preferably 5 ppm or less, and even more preferably 3 ppm or less, as cobalt atoms relative to the polyester resin.

[0037] Even when waste resin generated during the manufacturing process or recycled polyester resin recovered from the market (for example, PET bottles) is mixed with the polyester resin of the present invention, high-quality molded articles and the like can be obtained with minimal degradation.

[0038] <Method for manufacturing polyester resin> The present invention provides a method for producing polyester resin, which includes a step of using an organic sulfonic acid compound as a polymerization catalyst in the raw materials for the polyester resin and carrying out an etherification reaction of the glycol component.

[0039] In this invention, by including a step of etherification reaction before polycondensation reaction, the amount of carboxyl-terminated groups in the polyester resin can be increased and the cyclic oligomer content can be reduced. Furthermore, the total content of etherified products can be kept within a specific range. As a result, a polyester resin with excellent transparency when molded can be obtained.

[0040] (raw materials) Examples of raw materials for polyester resins include glycol components containing ethylene glycol, dicarboxylic acid components containing terephthalic acid, and esterified products as lower-order condensates consisting of glycol components and dicarboxylic acid components.

[0041] Methods for obtaining the above esterified product include, for example, directly reacting terephthalic acid, ethylene glycol, and other copolymer components as needed, distilling off the water, and esterifying to obtain an esterified product as a raw material for polyester resin. Alternatively, reacting dimethyl terephthalate, ethylene glycol, and other copolymer components as needed, distilling off the methyl alcohol, and transesterifying to obtain an esterified product. The esterification and transesterification reactions may be carried out in one step or in multiple steps.

[0042] A slurry containing preferably 1.02 to 2.5 moles, more preferably 1.03 to 1.8 moles, of ethylene glycol per mole of dicarboxylic acid or its ester derivative is prepared, and this slurry is continuously supplied to an esterification reactor to obtain an esterified product.

[0043] Esterification reactions are carried out under reflux conditions of ethylene glycol, while removing the water or alcohol produced by the reaction from the system using a rectification column. Esterification reactions can also be carried out using a multi-stage apparatus consisting of multiple esterification reactors connected in series.

[0044] When the esterification reaction is carried out in multiple steps, the temperature of the first step is preferably 240-270°C, and more preferably 245-265°C. The pressure is 0.2-3 kg / cm². 2 It is preferably G, and 0.5-2 kg / cm³ 2 It is more preferable that it be G. The temperature of the final esterification reaction is preferably 250-290°C, and more preferably 255-275°C. The pressure is 0-1.5 kg / cm². 2 It is preferably G, and 0-1.3 kg / cm³ 2 It is more preferable that it be G.

[0045] When an esterification reaction is carried out in three or more steps, the reaction conditions for the intermediate esterification step are preferably between the reaction conditions for the first step and the reaction conditions for the final step. In a multi-step esterification reaction, it is preferable to increase the reaction rate smoothly at each step. Ultimately, the esterification reaction rate should preferably reach 90% or more, and more preferably 93% or more. These esterification reactions yield esterified products with a preferred molecular weight of approximately 500 to 5000. When terephthalic acid is used in an esterification reaction, the reaction proceeds due to the catalytic action of terephthalic acid as an acid.

[0046] To the esterified product obtained as described above, an organic sulfonic acid compound is added as a polymerization catalyst, and then an etherification reaction is carried out. Subsequently, a polycondensation reaction is carried out to obtain the polyester resin of the present invention.

[0047] (catalyst) In the present invention, by using an organic sulfonic acid compound as a polymerization catalyst, the total content of etherified products and the content of cyclic oligomers can be easily controlled within the scope of the present invention. This is because it is presumed that using an organic sulfonic acid compound increases the amount of carboxyl-terminal groups in the polyester resin during the polymerization reaction, while decreasing the amount of hydroxyl-terminal groups that serve as the starting point for the formation of cyclic oligomers. Examples of organic sulfonic acid compounds include benzenesulfonic acid, m- or p-benzenedisulfonic acid, 1,3,5-benzenetrisulfonic acid, o-, m- or p-sulfobenzoic acid, benzaldehyde-o-sulfonic acid, acetophenone-p-sulfonic acid, acetophenone-3,5-disulfonic acid, o-, m- or p-aminobenzenesulfonic acid, sulfanilic acid, 2-aminotoluene-3-sulfonic acid, and phenylhydroxyl Min-3-sulfonic acid, phenylhydrazine-3-sulfonic acid, 1-nitronaphthalene-3-sulfonic acid, thiophenol-4-sulfonic acid, anisole-o-sulfonic acid, 1,5-naphthalenedisulfonic acid, o-, m- or p-chlorobenzenesulfonic acid, o-, m- or p-bromobenzenesulfonic acid, o-, m- or p-nitrobenzenesulfonic acid, nitrobenzene-2,4-disulfonic acid, nitrobenzene-3,5-disulfonic acid Nitrobenzene-2,5-disulfonic acid, 2-nitrotoluene-5-sulfonic acid, 2-nitrotoluene-4-sulfonic acid, 2-nitrotoluene-6-sulfonic acid, 3-nitrotoluene-5-sulfonic acid, 4-nitrotoluene-2-sulfonic acid, 3-nitro-o-xylene-4-sulfonic acid, 5-nitro-o-xylene-4-sulfonic acid, 2-nitro-m-xylene-4-sulfonic acid, 5-nitro-m-xylene-4-sulfonic acid , 3-nitro-p-xylene-2-sulfonic acid, 5-nitro-p-xylene-2-sulfonic acid, 6-nitro-p-xylene-2-sulfonic acid, 2,4-dinitrobenzenesulfonic acid, 3,5-dinitrobenzenesulfonic acid, o-, m- or p-fluorobenzenesulfonic acid, 4-chloro-3-methylbenzenesulfonic acid, 2-chloro-4-sulfobenzoic acid, 5-sulfosalicylic acid, 4-sulfophthalic acid, 2-sulfobenzoic anhydride, 3,4-dimethyl-2-sulfobenzoic anhydride, 4-methyl-2-sulfobenzoic anhydride, 5-methoxy-2-sulfobenzoic anhydride, 1-sulfonaphthoic anhydride, 8-sulfonaphthoic anhydride, 3,6-disulfophthalic anhydride, 4,6-disulfisophthalic anhydride, 2,5-disulfoterephthalic anhydride, methanesulfonic acid, ethanesulfonic acid, methionic acid, cyclopentanesulfonic acid, 1,1-ethanedisulfonic acid, 1,2-ethanedisulfonic acid, 1,2-ethanedisulfonic anhydride, 3 Examples include propanedisulfonic acid, β-sulfopropionic acid, isethionic acid, nithionic acid, nithionic anhydride, 3-oxy-1-propanesulfonic acid, 2-chloroethanesulfonic acid, phenylmethanesulfonic acid, β-phenylethanesulfonic acid, α-phenylethanesulfonic acid, ammonium chlorosulfonate, methyl benzenesulfonate, ethyl p-toluenesulfonate, ethyl methanesulfonate, dimethyl 5-sulfosalicylate, trimethyl 4-sulfophthalate, and salts thereof. Among these, from the viewpoint of versatility, 2-sulfobenzoic anhydride, o-sulfobenzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 5-sulfosalicylic acid, benzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, 5-sulfisophthalic acid, and salts thereof are preferred.

[0048] Organic sulfonic acid compounds can be added to polyester raw materials, for example, in solid form, slurry form, or as a solution dissolved in water, glycol, etc.

[0049] The amount of organic sulfonic acid compounds added varies depending on the type, but it is approximately 0.5 × 10⁻⁶ per mole of the acid component constituting the polyester resin. -4 ~40×10 -4 It is preferable to use moles, 1.0 × 10 -4 ~20.0×10 -4It is more preferable that the amount added is in moles. If the amount added is less than the above range, the cyclic oligomer content may not be within the range of the present invention, a polyester resin with a high degree of polymerization may not be obtainable in a short time, or the total content of etherified products may become too low. On the other hand, if it exceeds the above range, it may cause discoloration of the polyester resin.

[0050] By setting the amount of organic sulfonic acid compound added within the above range, the sulfur content of the resulting polyester resin can be preferably 1 to 500 ppm, more preferably 2 to 250 ppm, and even more preferably 2 to 50 ppm. If the sulfur content is less than 1 ppm, the mechanical properties may be inferior. On the other hand, if it exceeds 500 ppm, the strength of the molded article may decrease, or it may cause discoloration of the polyester.

[0051] When a metal-based catalyst is not used as the polymerization catalyst, the amount of metal components derived from the metal-based catalyst in the resulting polyester resin of the present invention can be reduced. If the amount of metal components is high, transparency may be poor or foreign matter may be generated during melt processing. The amount of metal components is preferably 1 ppm or less, more preferably 0.5 ppm or less, and even more preferably 0 ppm. Examples of metal-based catalysts include compounds such as antimony, germanium, tin, titanium, zinc, aluminum, iron, magnesium, potassium, calcium, sodium, manganese, nickel, and cobalt.

[0052] (Etherification reaction) The temperature of the etherification reaction is preferably 240°C or higher, more preferably 240 to 300°C, and even more preferably 250 to 280°C. If the temperature is below 240°C, the reaction may not proceed sufficiently, and the content of cyclic oligomers and the total content of etherified products in the polyester resin may fall outside the specified range. If the temperature of the etherification reaction exceeds 300°C, decomposition of the esterified products will proceed during the reaction, and the resulting polyester resin may have reduced mechanical properties such as elongation at break when molded.

[0053] The time of the etherification reaction (heating time) is preferably 5 to 120 minutes, more preferably 10 to 60 minutes. If the reaction time is less than 5 minutes, the etherification reaction may not proceed sufficiently, and the content of cyclic oligomers and the total content of etherified products in the polyester resin may deviate from the specific range. If the reaction time exceeds 120 minutes, the decomposition of the esterified product may proceed during the reaction, and the resulting polyester resin may have deteriorated mechanical properties.

[0054] The etherification reaction is preferably carried out under normal pressure or pressure, and the pressure is preferably 0 to 3.0 kg / cm 2 G.

[0055] By adjusting the molar ratio (G / A) of the glycol component (G) to the acid component (A) in the raw materials used for the etherification reaction, the production amount of cyclic oligomers and the production amount of the etherified product of ethylene glycol can be made within a preferable range. G / A is preferably 1.05 to 3.00, more preferably 1.10 to 2.00. To adjust G / A, if necessary, a glycol component such as ethylene glycol may be additionally added to the raw materials of the polyester resin. If G / A is less than 1.05, the production amount of the etherified product may be too small or the production amount of cyclic oligomers may not be suppressed. On the other hand, if G / A exceeds 3.00, the production amount of the etherified product may be too large.

[0056] (Polycondensation reaction) After the etherification reaction, a polycondensation reaction can be carried out to obtain the polyester resin of the present invention. Examples of the polycondensation reaction include a melt polycondensation reaction. The polycondensation reaction may be carried out in one step or divided into multiple steps. The conditions for the polycondensation reaction are not particularly limited, but in the first stage of the polycondensation reaction, the temperature is preferably 250 to 290°C, and more preferably 260 to 280°C. The pressure is preferably 500 to 20 Torr, and more preferably 200 to 30 Torr.

[0057] In the case of a multi-stage reaction, the temperature of the final polycondensation reaction is preferably 265-300°C, and more preferably 275-295°C. The pressure is preferably 10-0.1 Torr, and more preferably 5-0.5 Torr. When the reaction is carried out in three or more stages, the reaction conditions of the intermediate stages are preferably those between the reaction conditions of the first and final stages. It is preferable to smoothly increase the degree of polymerization in each of these stages.

[0058] To increase the degree of polymerization of the polyester resin, solid-phase polymerization may be performed after the polycondensation reaction. Conventional known methods can be used for solid-phase polymerization. For example, first, the polyester to be subjected to solid-phase polymerization is pre-crystallized by heating it at a temperature of 100 to 210°C for 1 to 5 hours in an inert gas atmosphere or under reduced pressure, in a water vapor or water vapor-containing inert gas atmosphere. Then, solid-phase polymerization is performed at a temperature of 190 to 230°C for 1 to 30 hours in an inert gas atmosphere or under reduced pressure.

[0059] Furthermore, to promote the crystallization of the polyester resin before solid-phase polymerization, the polyester obtained by the polycondensation reaction may be subjected to moisture absorption followed by heating and crystallization, or water vapor may be directly blown onto the polyester chips and then heated and crystallized.

[0060] In particular, polyester resins used in applications requiring low acetaldehyde or cyclic trimer content, such as heat-resistant hollow molded articles for low-flavor beverages and mineral water, are preferably subjected to solid-phase polymerization after melt polycondensation.

[0061] Batch or continuous reactors can be used for polycondensation or solid-phase polymerization reactions. The polycondensation and solid-phase polymerization reactions may be carried out continuously or in stages.

[0062] After polymerization, the thermal stability can be further enhanced by removing the catalyst or deactivating it by adding a basic compound.

[0063] When the polyester resin of the present invention contains other resins or additives, the addition stage is not particularly limited and can be selected according to the characteristics of the additive or the performance required of the polyester resin. For example, it can be added during or after polymerization of the polyester resin, or at any stage during molding of the polyester resin.

[0064] <Applications of polyester resin> (fiber) The fibers of the present invention are made of the polyester resin of the present invention. To obtain fibers using the polyester resin of the present invention, a conventional melt spinning method can be employed, for example, a method in which spinning and drawing are performed in two steps, or a method in which they are performed in one step. Furthermore, crimping can be imparted to the fibers, heat setting can be performed, or staples (short fibers) can be produced by a cutting process.

[0065] In the case of short fibers, fillers may be included to improve spinning operability and dispersibility when used for papermaking applications. Examples of fillers include inorganic substances such as silica or organic fillers. Furthermore, in the case of filaments (long fibers), the fibers may contain additives such as non-metallic matting agents to provide slipperiness and opacity.

[0066] The fibers of the present invention may be not only fibers in which all single fibers are formed from the polyester resin of the present invention, but may also be composite fibers formed by combining the polyester resin of the present invention with other polyester resins (such as virgin polyester resin or polyester resins containing other copolymer components). Examples of composite fiber forms include core-sheath type, side-by-side type, and sea-island type.

[0067] The proportion of the polyester resin of the present invention contained in the fibers of the present invention is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. If the fibers of the present invention are not composite fibers, the proportion is preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 100% by mass.

[0068] The fibers of the present invention may be processed into yarns by employing known yarn processing methods such as blending or spinning. In that case as well, it is preferable that the proportion of polyester resin contained in the fibers of the present invention be within the above range. Furthermore, the fibers of the present invention may be irregularly shaped cross-section yarns, hollow cross-section yarns, or dope-dyed yarns.

[0069] The fibers of the present invention may be monofilaments. For example, they can be used in applications such as stockings, fishing lines, fishing nets, bristles for various brushes, 3D printer filaments, artificial hair, racket strings, industrial fabrics, hexagonal netting, bird-repellent wire, musical instrument strings, interlining, brushes, electrical lead wires, and communication cable support materials.

[0070] The fibers of the present invention can be processed into woven or knitted fabrics or nonwoven fabrics. For example, they can be used in a variety of fiber applications, such as clothing fibers, artificial leather fibers, footwear fibers, interior and bedding fibers represented by curtains, tablecloths, carpets, futon batting, fiberfill, etc., outdoor product fibers such as tents, tensile wires such as sewing threads, tire cords, and ropes, industrial materials represented by civil engineering and construction materials, vehicle materials such as airbags, various woven fabrics, various knitted fabrics, nets, short fiber nonwoven fabrics, and long fiber nonwoven fabrics.

[0071] Nonwoven fabrics can be used not only on their own, but also laminated into multilayer laminates of two or more layers, such as nonwoven fabrics layered with other nonwoven fabrics or with films. Nonwoven fabrics can be used in a wide range of applications, including industrial materials such as supports for separation membranes or filter materials, various filters, battery separators, and house wraps, as well as medical applications such as masks and medical gowns, clothing applications, carpet applications, packaging materials, reinforcing materials for rubber products such as tires, belts, hoses, and tarpaulins, heavy fabrics, ropes, and nets.

[0072] (Molded body) The polyester resin of the present invention can be molded into molded bodies such as hollow molded bodies. Examples of hollow molded bodies include beverage containers for mineral water, juice, wine, or whiskey, baby bottles, bottled food containers, containers for hair products, cosmetics, etc., and containers for household and dish soap. In particular, taking advantage of the hygienic properties, strength, and solvent resistance of the polyester resin, it is especially suitable for various beverage applications in the form of pressure-resistant vessels, heat-resistant and pressure-resistant vessels, and alcohol-resistant vessels.

[0073] As a method for manufacturing hollow molded bodies, a blow molding method can be employed in which polyester chips are dried by vacuum drying or the like, and then molded using a molding machine such as an extrusion molding machine or an injection molding machine; or a direct molding method is used in which the molten material after melt polymerization is introduced into a molding machine while still in a molten state to obtain a pre-molded body with a bottom, and this pre-molded body is then subjected to stretch blow molding, direct blow molding, or extrusion blow molding.

[0074] The hollow container may have a multilayer structure, such as a laminated bottle. For example, a multilayer structure may be provided with intermediate layers such as a gas barrier resin layer such as polyvinyl alcohol or polymetaxylylenediamine adipate, a light-shielding resin layer, or a recycled polyester layer. The inside and outside of the container can also be coated with a layer of metal such as aluminum or diamond-like carbon using methods such as vapor deposition or CVD (chemical vapor deposition).

[0075] The polyester resin of the present invention can also be used for hot-melt molding or potting applications. Hot melt molding refers to a method of molding resin (so-called insert molding) that involves melting resin without using a solvent and injecting the molten resin at low pressure (preferably 0.1 to 3 MPa) into a mold in which industrial parts (especially electronic parts) have been pre-placed, thereby forming the resin into a housing or case for the parts. The potting method refers to a method in which industrial components are placed in a housing or on a substrate beforehand, and molten resin is injected or dripped onto them at low pressure (preferably 1 MPa or less) to integrate the housing or substrate with the components.

[0076] Furthermore, the polyester resin of the present invention can also be mixed with a thermally conductive filler and molded into a desired shape using commonly known melt molding methods such as injection molding, compression molding, extrusion molding, transfer molding, and sheet molding to produce a thermally conductive molded body. Specific examples of heat-conductive molded bodies include encapsulants for semiconductor elements and resistors, electrical and electronic components such as connectors, sockets, and computer-related parts, household electrical appliance parts, heat dissipation sheets and heat dissipation members for releasing heat from electronic components to the outside, lighting fixture parts such as lamp sockets, communication equipment parts, printing press-related parts, mechanical parts such as gears, bearings, motor parts and cases, automotive mechanical parts, engine parts, engine compartment parts, electrical components, interior parts, and other automotive parts, cooking utensils such as heat-resistant tableware, hygiene products such as face shields, aircraft, spacecraft, and space equipment parts, and sensor parts.

[0077] (Sheet) The polyester resin of the present invention can be molded into a sheet. The sheet can be manufactured, for example, by extruding the polyester resin from an extruder into a sheet-like material. It can then be further processed by vacuum forming, pressure forming, embossing, etc. Applications of the sheet include trays or containers for food or general merchandise, cups, blister packs, carrier tapes for electronic components, trays for electronic component delivery, and various cards. The sheet can also have a multilayer structure with an intermediate layer such as a gas barrier resin layer, a light-shielding resin layer, or a recycled polyester layer.

[0078] (film) The polyester resin of the present invention can be formed into a film. One method of forming it into a film is to melt-extrude the polyester resin, form it into a sheet on a cooling rotary roll using a T-die, and create an unstretched film. Alternatively, a laminated film can be formed by co-extrusion using multiple extruders, with various functions assigned to the core layer and skin layer.

[0079] The film may be oriented. An oriented film can be produced, for example, by stretching it by 1.1 to 6 times in at least one axial direction at a temperature above the glass transition temperature of the polyester resin but below the crystallization temperature, using a known method.

[0080] Methods for manufacturing a biaxially oriented film include, for example, a sequential biaxial stretching method in which uniaxial stretching is performed in the longitudinal or transverse direction, and then in the orthogonal direction, and a simultaneous biaxial stretching method in which stretching is performed simultaneously in the longitudinal and transverse directions. Furthermore, as driving methods for simultaneous biaxial stretching, there are methods using a linear motor, and multi-stage stretching methods in which stretching is performed in the same direction in several stages, such as transverse-longitudinal-longitudinal stretching, longitudinal-transverse-longitudinal stretching, and longitudinal-longitudinal-transverse stretching. After stretching is completed, in order to reduce the thermal shrinkage rate of the film, it is preferable to perform a heat setting treatment at a temperature of (melting point - 50°C) to below the melting point for 30 seconds or less (preferably within 10 seconds), and to perform a longitudinal relaxation treatment of 0.5 to 10%, a transverse relaxation treatment, etc.

[0081] The film thickness is preferably 1 to 1000 μm, more preferably 5 to 500 μm, and even more preferably 10 to 200 μm. If the film is less than 1 μm thick, it lacks rigidity, and if it exceeds 1000 μm, it becomes too rigid, making it difficult to handle in either case.

[0082] To impart various functions such as adhesion, release properties, antistatic properties, infrared absorption, antibacterial properties, and scratch resistance to the surface of the film, a coating layer made of polymer resin may be provided, for example, by a coating method. Alternatively, inorganic particles and / or organic particles may be included only in the coating layer to create a smooth, highly transparent film. Furthermore, by providing an inorganic vapor deposition layer on the surface of the film, various barrier functions such as protection against oxygen, water, and oligomers can be imparted, or by providing a conductive layer by a sputtering method or the like, conductivity can be imparted.

[0083] Furthermore, in order to improve handling characteristics such as slipperiness, runability, abrasion resistance, and winding ability, inert particles such as inorganic particles, organic salt particles, or crosslinked polymer resin particles may be included to form irregularities on the film surface. These inert particles can be added at any stage during or after polymerization of the polyester resin, or after the film has been formed. Inert particles may be surface-treated with inorganic or organic materials, hydrophilic or hydrophobic, or they may be untreated. However, surface-treated particles may be preferable, for example, to improve dispersibility.

[0084] Examples of inorganic particles include calcium carbonate, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, lithium fluoride, and sodium calcium aluminum silicate. Examples of organic salt particles include terephthalates such as calcium oxalate, calcium, barium, zinc, manganese, and magnesium. Examples of crosslinked polymer resin particles include divinylbenzene, styrene, acrylic acid, methacrylic acid, and vinyl monomers of acrylic acid or methacrylic acid, either alone or as copolymers. Other examples include organic particles such as polytetrafluoroethylene, benzoguanamine resin, thermosetting epoxy resin, unsaturated polyester resin, thermosetting urea resin, and thermosetting phenolic resin.

[0085] The method for incorporating inert particles is not limited to the following methods (a) to (d). (a) A method in which inert particles are dispersed in a slurry form in a glycol component, which is a constituent of polyester resin, and added to the polymerization reaction system of polyester. (b) A method in which an aqueous slurry of inert particles dispersed in a vented twin-screw extruder is added to molten polyester resin in the melt extrusion process. (c) A method of kneading polyester resin and inert particles in a molten state. (d) A method of kneading a master resin of polyester resin and inert particles in a molten state.

[0086] In the case of method (a) described above, it is preferable to add the inert particle slurry to the reaction system with low melt viscosity before the start of the polycondensation reaction, before the esterification or transesterification reaction. Furthermore, when preparing the inert particle slurry, it is preferable to perform physical dispersion treatment such as using a high-pressure disperser, bead mill, or ultrasonic dispersion. In addition, it is preferable to use appropriate chemical dispersion stabilization treatment depending on the type of particles used to stabilize the dispersed slurry.

[0087] As a dispersion stabilization treatment, for example, in the case of crosslinked polymer resin particles having carboxyl groups on the particle surface, an alkali compound such as sodium hydroxide, potassium hydroxide, or lithium hydroxide is added to the slurry to suppress re-aggregation between particles by electrical repulsion. In the case of calcium carbonate particles, hydroxyapatite particles, etc., it is preferable to add sodium tripolyphosphate or potassium tripolyphosphate to the slurry.

[0088] Furthermore, when adding an inert particle slurry to a polyester polymerization reaction system, it is preferable to heat the slurry to near the boiling point of the glycol component in order to reduce the heat shock (temperature difference between the slurry and the polymerization reaction system) when it is added to the polymerization reaction system and to improve dispersibility.

[0089] Since the polyester resin of the present invention has excellent thermal stability, for example, when creating films, the edges of the film generated during the stretching process or off-spec films can be melted and reused.

[0090] The film of the present invention can be used, for example, as an antistatic film, an easy-adhesion film, a release film, for cards, dummy cans, food packaging, agriculture, building materials, decorative materials, wallpaper, OHP film, printing, inkjet recording, sublimation transfer recording, laser beam printer recording, electrophotographic recording, thermal transfer recording, thermal transfer recording, printed circuit board wiring, membrane switches, plasma displays, touch panels, masking films, photoengraving, X-ray films, photographic negative films, phase difference films, polarizing films, polarizing film protection (TAC), protective films, photosensitive resin films, field-of-view films, diffusion sheets, reflective films, anti-reflective films, conductive films, magnetic tapes, film capacitors, separators, UV protection, backgrind tapes, and the like.

[0091] (glue) The polyester resin of the present invention is suitably used as an adhesive. The adhesive may contain a solvent or various additives. When the polyester resin of the present invention is used as a hot-melt adhesive, various methods can be employed, such as molding it into various shapes such as pellets, powders, sheets, films, or nonwoven fabrics and sandwiching them between the adherends before heat bonding; applying it to the adherends using a melting applicator and then bonding them together; or coating the adherends with a film or tube-like material using an extruder and then bonding them together.

[0092] Examples of adhesives include adhesives for packaging materials, paper containers, lids, in-mold transfer foils, PP steel sheets, solar cell modules, flocking adhesives, binders for secondary battery electrodes, adhesives for secondary battery casings, automotive belt moldings, automotive components, adhesives for dissimilar substrates, and fiber consolidators. Furthermore, it can be used as an anchor coating agent or primer, for example, for PP extrusion lamination, UV-curing coating agents, shoe primers, automobile bumper primers, and clear box primers.

[0093] (Thermal conductive composition) The polyester resin of the present invention can also be made into a thermally conductive composition by mixing it with a thermally conductive filler. Specific applications of the thermally conductive composition include those listed above as examples of thermally conductive molded articles.

[0094] (powder) The polyester resin of the present invention can be used as a raw material when producing a resin molded product by processing it into a powder, filling it into a mold, and compression molding it, or as a filler to be blended into a resin. A resin molded product obtained using polyester resin powder as a raw material can be used, for example, in connectors and LED reflectors. Furthermore, a resin blended with polyester resin filler can be used, for example, in abrasives.

[0095] The powder can also be used as a powder coating. Powder coatings can be used, for example, for bicycle baskets, gardening supplies, kitchenware, clothing, refrigerator shelves, freezer display cases, dishwasher baskets, handles, shopping carts, fences, gratings, steel pipe joint lower pipes, branch anchor parts, building spacers, protective shelves, steel pipes, panel tanks, valves, automobile parts, vehicle handles, rail fasteners, bonnet stays, outdoor unit fan covers, booth bars, telephone poles, telephone cable parts, overhead line hardware bands, conduit joints, industrial piping, piping equipment, flanges and valves, sulfuric acid tanks, tank truck interiors, joint interior coatings, piping equipment, heat exchangers, sewage treatment equipment, plating jigs, etc.

[0096] (Resin solution) The polyester resin of the present invention can be dissolved or dispersed in various solvents and can be used in various applications in the form of a resin solution. In the present invention, the term "resin solution" includes both a solution in which the polyester resin is dissolved and a solution in which the polyester resin is dispersed.

[0097] Examples of solvents include water, methanol, ethanol, propanol, isopropanol, acetone, methyl ethyl ketone, methyl acetate, ethyl acetate, hexafluoroisopropanol, methylene chloride, chloroform, tetrachloroethane, trifluoroacetic acid, benzene, toluene, xylene, cresol, trimethylbenzene, triethylamine, triethanolamine, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, sulfolane, and cyclohexanone. These solvents may be used individually or in combination of two or more. They may also be mixed with other solvents. The solvents can be appropriately selected considering the type of polyester resin, degree of polymerization, desired concentration, etc.

[0098] The resin solution may contain additives such as inorganic fillers, binders, antioxidants, wetting agents, and leveling agents.

[0099] When using the polyester resin of the present invention in reaction with other resins or curing agents, the resin solution of the present invention and the solution of the other resin or curing agent may be prepared separately, mixed immediately before use, and then the two resins may be reacted and cured by coating and drying or the like.

[0100] By applying and drying the resin solution of the present invention, coatings, laminates, films, etc., can be formed. Specific examples of substrates that can be used when forming coatings and laminates include glass substrates, various metal plates, polyethylene terephthalate film, polycarbonate film, cycloolefin film, polyimide film, polyamide film, and the like.

[0101] The method for applying the resin solution to the substrate is not particularly limited, but examples include wire bar coating, film applicator coating, spray coating, gravure roll coating, screen printing, reverse roll coating, lip coating, air knife coating, curtain flow coating, immersion coating, die coating, spray, relief printing, intaglio printing, and inkjet printing. The coating can be formed using conventional methods and apparatus, and is obtained by applying the resin solution of the present invention to the substrate and drying the solvent components.

[0102] The resin solution of the present invention can be used as a can coating. Examples of metal plates used as coating equipment for can coating include sheet-shaped or strip-shaped steel plates, aluminum plates, or those with various plating or chemical treatments applied to their surfaces. After applying the resin solution to the metal plate, a coating film can be formed on the metal surface by baking. The metal plate with the coating film can be used as a component requiring processability, such as the can body and lid of a two-piece can, or the can body and bottom lid of a three-piece can.

[0103] The resin solution of the present invention can also be used as a separator for energy storage elements such as lithium-ion secondary batteries. A porous membrane made using the resin solution may be used as a separator, or a porous coating of the present invention may be formed on one or both sides of an existing separator using the resin solution of the present invention and then used as a separator. Furthermore, the resin solution of the present invention can also be used in the production of prepregs. Prepregs can be obtained by impregnating or coating a reinforced fiber cloth with a resin solution, which is obtained by dissolving a compound that reacts and polymerizes with polyester in an organic solvent, and then drying it. Furthermore, the resin solution of the present invention can also be used in paints, coatings, adhesives, varnishes, and the like.

[0104] The various articles (coatings, films, various component materials, paint films, etc.) manufactured using the resin solution of the present invention may be further subjected to annealing treatment. This further hardens the resin, improving heat resistance, hardness, etc. The annealing temperature is, for example, above the drying temperature, preferably around 100°C to 280°C. [Examples]

[0105] The present invention will be described in detail below based on examples, but the present invention is not limited thereto. Measurement and evaluation were performed by the following methods.

[0106] (1) Intrinsic viscosity [η] The measurement was performed at 20°C using an equimassive mixture of phenol and tetrachloroethane as the solvent.

[0107] (2) Composition of polyester resin 10 mg of the sample was dissolved in 1 mL of a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 9 / 1 (mass ratio), and the results were obtained by NMR using a JEOL LA-400 NMR spectrometer. 1 1H-NMR was measured, and the total amounts of the dicarboxylic acid component, triethylene glycol component, and tetraethylene glycol component, as well as the molar ratios of the other glycol components, were calculated from the integrated proton peak intensities of each component in the resulting chart.

[0108] Next, triethylene glycol and tetraethylene glycol were quantified as described below. The polyester resin was hydrolyzed in a 0.75 N potassium hydroxide / methanol solution, and then neutralized with terephthalic acid. Next, the filtrate obtained by filtration was measured by gas chromatography, and the molar ratio of triethylene glycol to tetraethylene glycol was calculated using a pre-prepared calibration curve. These molar ratios were then compared with the aforementioned method. 1Based on the results of 1H-NMR measurements (the total amount of triethylene glycol and tetraethylene glycol, and the molar ratio of each other glycol component), the content of triethylene glycol and tetraethylene glycol in the total glycol components was calculated.

[0109] (4) Oligomer content 100 mg of polyester resin was dissolved in a mixed solvent of hexafluoroisopropanol and chloroform in a volume ratio of 1 / 20, acetonitrile was added, and after extraction, the content of dimers to decamers (cyclic and acyclic oligomers) was calculated by measuring under the following conditions using liquid chromatography. Column: Waters Microbonder Sphere Filler: Si-C18S 5μ 100A Detector: Waters 2996 PDA detector (light source wavelength 254 nm) Flow rate during measurement: 1.0 mL / min Mobile phase solvent: Acetonitrile / water = 7 / 3 and acetonitrile

[0110] (5) Carboxylate terminal group The solution was obtained by dissolving 0.1 g of polyester resin in 10 ml of benzyl alcohol, adding 10 ml of chloroform to the solution, and then titrating with a 1 / 10 N potassium hydroxide benzyl alcohol solution.

[0111] (6) Sulfur content Polyester resin was melt-molded at 300°C to form a disc-shaped molded plate with a diameter of 3 cm and a thickness of 1 cm. Quantitative analysis was performed using the calibration curve method with a Rigaku ZSX Primus X-ray fluorescence analyzer.

[0112] (7) Hayes Polyester resin was injected into a Nissei Plastics injection molding machine PS-200, and plates measuring 50 mm in length, 50 mm in width, and 1 mm in thickness were produced at a cylinder temperature of 285°C and a mold temperature of 40°C. The turbidity of the obtained plates was evaluated using a turbidity system MODEL 1001DP manufactured by Nippon Denshoku Industries Co., Ltd. A smaller value indicates better transparency; for example, air haze is 0%.

[0113] (8) Oligomer content when formed into a molded product A molded body was obtained as described in (7) above. Then, 100 mg of this molded body was used as a sample, and the oligomer content was measured in the same manner as in (4) above.

[0114] (9) Oligomer content when used as fiber Using the obtained polyester resin, it was spun from a spinning nozzle (84 holes) at a resin temperature of 295°C using an extruder-type melt spinning machine, and wound up at a spinning speed of 2900 m / min to obtain multifilament (partially oriented undrawn yarn). Subsequently, it was drawn at a drawing temperature of 90°C and a heat setting temperature of 150°C to obtain multifilament (drawn yarn) with a total fineness of 45 dtex. 100 mg of the obtained multifilament (drawn yarn) was used as a sample, and the oligomer content was measured in the same manner as in (4) above.

[0115] (10) Stretchability In the stretching process described in (9) above, the number of times the thread broke when stretching was performed continuously for 6 hours was counted, and the thread breakage rate (%) was calculated and evaluated using the following formula. Thread breakage rate (%) = {(Total number of spindles drawn) - (Number of spindles that could be drawn without thread breakage in 6 hours)} ÷ (Total number of spindles drawn) × 100 ○: Thread breakage rate during stretching ≤ 5% ×: Thread breakage rate during stretching > 5%

[0116] (11) Stainability The multifilaments (drawn yarns) obtained in the same manner as in (9) above were knitted into tubular fabric using a knitting machine (manufactured by Koike Machinery Works, number of needles: 300, bobbin diameter: 3.5 inches). The prepared tubular fabrics were dyed at 130°C for 30 minutes under conditions of 0.3% owf using a dye solution containing Sumikalon as a disperse dye and Disper TL as a dispersant. Thirty dyed tubular fabrics were visually inspected to evaluate for the presence or absence of dye streaks and uneven dyeing, and the number of good products without dye streaks or uneven dyeing was counted and evaluated as follows. ○: Number of good quality items is 27 or more. ×: The number of good quality items is 26 or less.

[0117] [Preparation of esterified A] A slurry of terephthalic acid and ethylene glycol (molar ratio 1 / 1.6) was continuously supplied to an esterification reaction vessel, and the reaction was carried out under conditions of a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours to obtain esterified product A (terephthalic acid:ethylene glycol = 100:111 (molar ratio)). [Preparation of esterified compound B] A slurry of isophthalic acid and ethylene glycol (molar ratio 1 / 3.5) was supplied to an esterification reaction vessel, and the reaction was carried out for 4 hours at a temperature of 200°C and a pressure of 0.2 MPa to obtain esterified product B (isophthalic acid:ethylene glycol = 100:332 (molar ratio)).

[0118] Example 1 The heated and melted esterified product A was added to a polycondensation reaction vessel heated to 280°C, and 2.0 × 10⁻¹ 2-sulfobenzoic anhydride (OSB) was added. -4 The molar ratio of the acid component was added, and the etherification reaction was carried out at atmospheric pressure at 280°C for 10 minutes. Next, while maintaining the temperature of the reaction vessel at 280°C, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 3 hours to obtain a polyester resin. The polyester resin contained 12 ppm of sulfur and 0.8 mol% triethylene glycol.

[0119] Examples 2-6 Polyester resins were obtained by performing the same procedure as in Example 1, except that the organic sulfonic acid compounds were changed to 5-sulfosalicylic acid dianhydride (SS), o,m,p-aminobenzenesulfonic acid (o,m,p-ABS), and p-methyl toluenesulfonate (p-TSMe), respectively. All polyester resins contained a sulfur component of 1 ppm or more, and the amount of triethylene glycol was 0.2 mol% or more.

[0120] Example 7 The heated and melted esterified product A was added to a polycondensation reaction vessel heated to 250°C, and 2.0 × 10⁻⁶ 5-sulfosalicylic acid dianhydride (SS) was added. -4 The mol / mol ratio of the acid component was added, and the etherification reaction was carried out at atmospheric pressure at 250°C for 60 minutes. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 4 hours to obtain a polyester resin. The polyester resin contained 12 ppm of sulfur component and the amount of triethylene glycol was 1.1 mol%.

[0121] Example 8 A polyester resin was obtained by following the same procedure as in Example 7, except that the etherification reaction time was changed to 120 minutes. The polyester resin contained 12 ppm of sulfur and 1.2 mol% triethylene glycol.

[0122] Example 9 100 parts by mass of heated and melted esterified product A was added to a polycondensation reaction vessel heated to 250°C. Then, 6 parts by mass of ethylene glycol was added to make the G / A ratio 1.31, followed by 2.0 × 10⁻⁶ of 5-sulfosalicylic acid dianhydride (SS). -4The molars of the acid component were added, and the etherification reaction was carried out at atmospheric pressure at 250°C for 30 minutes. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 4 hours to obtain a polyester resin. The polyester resin contained 12 ppm of sulfur component, with triethylene glycol content at 2.8 mol% and tetraethylene glycol content at 0.1 mol%.

[0123] Example 10 A polyester resin was obtained by performing the same procedure as in Example 9, except that the etherification reaction time was changed to 60 minutes. The polyester resin contained 15 ppm of sulfur, with a triethylene glycol content of 3.4 mol% and a tetraethylene glycol content of 0.2 mol%.

[0124] Example 11 A polyester resin was obtained by performing the same procedure as in Example 10, except that 12 parts by mass of ethylene glycol were added to achieve a G / A ratio of 1.51. The polyester resin contained 14 ppm of sulfur, with a triethylene glycol content of 2.8 mol% and a tetraethylene glycol content of 0.2 mol%.

[0125] Example 12 Heat-molten esterified product A (100 parts by mass) and esterified product B (19 parts by mass) are placed in a polycondensation reaction vessel heated to 260°C, and 2.0 × 10⁻⁶ 5-sulfosalicylic acid dianhydride (SS) are added. -4 The molars of the acid component were added, and the etherification reaction was carried out at 260°C for 10 minutes under atmospheric pressure. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 4 hours to obtain a polyester resin. The polyester resin contained 10 ppm of sulfur component, with a triethylene glycol content of 1.6 mol% and a tetraethylene glycol content of 0.1 mol%.

[0126] Examples 13-18 Polyester resins were obtained by performing the same procedure as in Example 12, except that the amount of esterified compound B added was changed as shown in Table 1. All polyester resins contained 10 ppm or more of sulfur, with a triethylene glycol content of 1.9 mol% or more and a tetraethylene glycol content of 0.1 mol% or more.

[0127] Example 19 The heated and melted esterified product A was added to a polycondensation reaction vessel heated to 250°C, and 2.0 × 10⁻⁶ 5-sulfosalicylic acid dianhydride (SS) was added. -4 The molars of the acid component were added, and the etherification reaction was carried out at atmospheric pressure at 250°C for 180 minutes. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 5 hours to obtain a polyester resin. The polyester resin contained 21 ppm of sulfur and 1.8 mol% triethylene glycol.

[0128] Example 20 100 parts by mass of heated and melted esterified product A was added to a polycondensation reaction vessel heated to 250°C, and then 62 parts by mass of ethylene glycol was added so that the G / A ratio was 3.11, followed by 2.0 × 10⁻⁶ of 5-sulfosalicylic acid dianhydride (SS). -4 The molars of acid were added, and the etherification reaction was carried out at atmospheric pressure at 250°C for 60 minutes. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 5 hours to obtain a polyester resin. The resulting polyester resin contained 25 ppm of sulfur, with a triethylene glycol content of 5.3 mol% and a tetraethylene glycol content of 0.4 mol%.

[0129] Table 1 shows the manufacturing conditions and polyester resin composition for Examples 1 to 20. [Table 1]

[0130] Table 2 shows the polyester resin properties and evaluation results obtained in Examples 1 to 20. [Table 2]

[0131] Comparative Example 1 100 parts by mass of heated and molten esterified product A was added to a polycondensation reaction vessel heated to 280°C, and 2.3 × 10⁻⁶ antimony trioxide (Sb) was added. -4 Moles of acid were added, and without performing the etherification reaction, the temperature of the reaction vessel was maintained at 280°C while the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 2 hours to obtain a polyester resin.

[0132] Comparative Example 2 100 parts by mass of heated and molten esterified product A was added to a polycondensation reaction vessel heated to 280°C, and 2.3 × 10⁻⁶ antimony trioxide (Sb) was added. -4 The molars of the acid component were added, and the etherification reaction was carried out at atmospheric pressure at 280°C for 60 minutes. While maintaining the temperature of the reaction vessel at 280°C, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 2 hours to obtain a polyester resin.

[0133] Comparative Example 3 Antimony trioxide (Sb) 2.3 × 10 -4 Molar / acid component is tetra-n-butyl titanate (TBT) 0.8 × 10⁻⁶ -4 A polyester resin was obtained by performing the same procedure as in Comparative Example 1, except for changing the molar / acid component.

[0134] Comparative Example 4 100 parts by mass of heated and melted esterified product A was added to a polycondensation reaction vessel heated to 280°C, and 2.0 × 10⁻⁶ 5-sulfosalicylic acid dianhydride (SS) was added. -4Moles of acid were added, and without performing the etherification reaction, the temperature of the reaction vessel was maintained at 280°C while the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 3 hours to obtain a polyester resin.

[0135] Comparative Example 5 100 parts by mass of heated and melted esterified product A was added to a polycondensation reaction vessel heated to 230°C, and 2.0 × 10⁻⁶ 5-sulfosalicylic acid dianhydride (SS) was added. -4 The molars of acid were added, and the etherification reaction was carried out at atmospheric pressure at 230°C for 10 minutes. Next, the temperature of the reaction vessel was raised to 280°C in 10 minutes, and while maintaining the temperature, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 2 hours to obtain a polyester resin.

[0136] Comparative Example 6 100 parts by mass of heated and molten esterified product A was added to a polycondensation reaction vessel heated to 280°C, and 2.3 × 10⁻⁶ antimony trioxide (Sb) was added. -4 Moles of acid were added, and without performing the etherification reaction, the temperature of the reaction vessel was maintained at 280°C while the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 2 hours to obtain a polyester resin. The obtained polyester resin pellets were crushed to an average particle size of 1.0-1.5 mm and 500 g were packed into a high-pressure container. Subsequently, high-pressure carbon dioxide with 6 mol% ethanol added was continuously supplied to the container at a flow rate of 50 ml / min for 120 minutes at a pressure of 20 MPa and a temperature of 80°C to extract the oligomers. After the extraction process, the polyester resin was removed and evaluated.

[0137] Comparative Example 7 Antimony trioxide (Sb) 2.3 × 10 -4 Molar / acid component is tetra-n-butyl titanate (TBT) 0.8 × 10⁻⁶ -4 A polyester resin was obtained by performing the same procedure as in Comparative Example 6, except for changing the molar / acid component.

[0138] Table 3 shows the manufacturing conditions and polyester resin compositions for Comparative Examples 1 to 7. [Table 3]

[0139] Table 4 shows the polyester resin properties and evaluation results obtained in Comparative Examples 1 to 7. [Table 4]

[0140] The polyester resins obtained in Examples 1 to 20 had a low cyclic oligomer content, and the total etherified content was within the range of the present invention. When these polyester resins were molded into articles, the formation of cyclic oligomers was suppressed, and transparency was good. When they were made into fibers, the formation of oligomers was also suppressed, and stretchability and dyeability were good.

[0141] In Comparative Examples 1-3, a metal catalyst was used as the polymerization catalyst to obtain polyester resin. The cyclic oligomer content was higher than that of the present invention, and the amount of cyclic oligomers generated when molded was also high, resulting in poor transparency. When made into fibers, the amount of oligomers generated was also high, resulting in poor stretchability and dyeability.

[0142] In Comparative Example 4, a polyester resin was obtained without performing an etherification reaction. The cyclic oligomer content was higher than the range of the present invention, and the amount of cyclic oligomers generated when it was made into a molded article was also high, resulting in poor transparency. When it was made into fibers, the amount of oligomers generated was also high, resulting in poor stretchability and dyeability.

[0143] In Comparative Example 5, a polyester resin was obtained by lowering the etherification reaction temperature. The cyclic oligomer content was higher than the range of the present invention, and the amount of cyclic oligomers produced when the molded article was increased, resulting in poor transparency. When the article was made into fibers, the amount of oligomers produced was also increased, resulting in poor stretchability and dyeability.

[0144] In Comparative Examples 6 and 7, the polyester resin obtained using a metal-based catalyst as a polymerization catalyst was subjected to an oligomer extraction treatment. Although the content of cyclic oligomers in the resin could be reduced, the amount of cyclic oligomers generated when it was remelted and molded into a product increased, resulting in poor transparency. The amount of oligomers generated also increased when it was made into fibers, resulting in poor stretchability and dyeability.

Claims

1. A polyester resin containing terephthalic acid and ethylene glycol as its main components. The total content of ethylene glycol ethers in the total glycol components is 4 A polyester resin having a molecular weight of 0 to 40.0 mol%, a cyclic oligomer content of 0.7 mass% or less, and a sulfur component content of 1 to 500 ppm.

2. The polyester resin according to claim 1, wherein the amount of carboxyl terminal groups is 20.0 eq / t or more.

3. The polyester resin according to claim 1 or 2, wherein the total content of cyclic oligomers and acyclic oligomers is 1.6% by mass or less.

4. The polyester resin according to any one of claims 1 to 3, wherein the diethylene glycol content is 2.5 mol% or more of the total glycol components.

5. A polyester resin according to any one of claims 1 to 4, wherein the triethylene glycol content is 0.1 to 5.5 mol% of the total glycol components.

6. A polyester resin according to any one of claims 1 to 5, wherein the tetraethylene glycol content is greater than 0.0 mol% and less than or equal to 2.0 mol% of the total glycol components.

7. A polyester resin according to any one of claims 1 to 6, wherein the total content of triethylene glycol and tetraethylene glycol is 7.0 mol% or less.

8. The polyester resin according to any one of claims 1 to 7, wherein the haze measured using a molded body with a thickness of 1 mm is 5% or less.

9. A molded article made of the polyester resin according to any one of claims 1 to 8.

10. A fiber made of the polyester resin described in any one of claims 1 to 8.

11. A film made of the polyester resin according to any one of claims 1 to 8.

12. A method for producing a polyester resin according to any one of claims 1 to 8, comprising the step of adding an organic sulfonic acid compound to a polyester resin raw material and carrying out an etherification reaction of a glycol component.

13. A method for producing a polyester resin according to claim 12, wherein the organic sulfonic acid compound is one or more selected from 2-sulfobenzoic acid anhydride, o-sulfobenzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 5-sulfosalicylic acid, benzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonate methyl, 5-sulfisophthalic acid, and salts thereof.

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