Monomer diol composition and method for producing polyester

Abstract

To provide a monomer diol composition capable of suppressing yellowish tone of an obtained polyester, without extending a necessary time of a polymerization later stage, when used in polymerization.SOLUTION: A monomer diol composition in which the measured value a of the hydroxyl value determined by the following measurement method divided by the theoretical value b of the hydroxyl value (a / b) is 0.980 or greater and less than 1.000. <Measurement Method> Step 1: Weigh the monomer diol composition to obtain the mass of the monomer diol composition. Step 2: Using the mass of the monomer diol composition obtained in Step 1, obtain the theoretical value b of the hydroxyl value of the monomer diol composition obtained in Step 1. Step 3: Measure the monomer diol composition obtained in Step 1 by NMR to obtain the measured value a of the hydroxyl value of the monomer diol composition. Step 4: Divide the measured value a of the hydroxyl value obtained in Step 3 by the theoretical value b of the hydroxyl value obtained in Step 2 to obtain the ratio (a / b).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a monomer diol composition. More specifically, the present invention relates to a monomer diol composition containing a monomer derived from a bioresource or a monomer diol derived from a recycled resource, which is also useful as a raw material for polyesters, polyurethanes, polycarbonates, etc. The present invention also relates to a method for producing polyesters using the monomer diol composition. [Background technology]

[0002] Conventionally, monomer diol compositions, which are raw materials for polyesters, have been produced using petroleum (fossil fuels) as raw materials. For example, there is a method for producing butanediol from butadiene produced from fossil fuels. However, with the growing demand for a circular (sustainable) society, there is a desire to move away from raw materials derived from fossil fuels such as petroleum, and in recent years, various methods for producing butanediol from biomass resources such as plants, which do not use fossil fuels as raw materials, have been proposed. For example, a method for producing butanediol by direct fermentation of sugar (Patent Document 1) and a method for producing butanediol by producing succinic acid from biomass resources and then reducing it with hydrogen have been proposed (Patent Document 2). Furthermore, a method for producing butanediol derived from recycled resources using waste materials such as waste polyester as raw materials has been proposed (Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special publication 2021-505539 [Patent Document 2] Chinese Patent Application Publication No. 114773153 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-323378 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the polyester polymerization reaction using a diol composition containing a monomer diol derived from a biomass resource or a monomer diol derived from a recycled resource disclosed in Patent Documents 1, 2, and 3, the time required for the latter stage of the polymerization reaction was long, making it impossible to efficiently produce polyester. In addition, the polyester obtained had a strong yellowish tint, and its quality was unsatisfactory.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a monomer diol composition which, when used in polymerization, does not prolong the time required for the late stage of the polymerization reaction and can suppress the yellowing of the obtained polyester to a low level. [Means for solving the problem]

[0006] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they found that the above-mentioned problems can be solved by using a monomer diol composition in which the value obtained by dividing the measured hydroxyl group amount by the theoretical hydroxyl group amount falls within a specific range, and thus they have completed the present invention. That is, the present invention relates to the following inventions.

[0007] [1] A monomer diol composition, in which the value (a / b) obtained by dividing the measured value (a) of the amount of hydroxyl groups measured by the following measurement method by the theoretical value (b) of the amount of hydroxyl groups is 0.980 or more and less than 1.000. <Measurement method> Step 1: Weighing the monomer diol composition to obtain the mass of the monomer diol composition Step 2: A step of obtaining a theoretical value b of the hydroxyl group content of the monomer diol composition obtained in Step 1 using the mass of the monomer diol composition obtained in Step 1. Step 3: A step of measuring the monomer diol composition obtained in Step 1 by NMR to obtain a measured value a of the amount of hydroxyl groups in the monomer diol composition. Step 4: A step of obtaining a value (a / b) by dividing the measured value a of the amount of hydroxyl groups obtained in Step 3 by the theoretical value b of the amount of hydroxyl groups obtained in Step 2.

[0008] [2] The monomer diol composition according to [1], wherein the monomer diol contained in the monomer diol composition is 85% by mass or more.

[0009] [3] The monomer diol composition according to [1] or [2], wherein the monomer diol composition in step 1 is a heated monomer diol composition.

[0010] [4] The monomer diol composition according to any one of [1] to [3], wherein the monomer diol composition is a liquid.

[0011] [5] The monomer diol composition according to any one of [1] to [4], wherein the monomer diol composition is in the form of a solution.

[0012] [6] The monomer diol composition according to any one of [1] to [5], wherein the monomer diol is an alkane diol.

[0013] [7] The monomer diol composition according to [6], wherein the alkanediol is an alkanediol produced using a biomass resource as a raw material.

[0014] [8] The monomer diol composition according to [7], wherein the alkanediol is an alkanediol produced by fermentation.

[0015] [9] The monomer diol composition according to [8], wherein the alkanediol is an alkanediol produced by direct fermentation of sugar.

[0016]

[10] The monomer diol composition according to [7], wherein the alkanediol is an alkanediol produced by hydrogen reduction of succinic acid or a succinic acid derivative produced using a biomass resource.

[0017]

[11] The monomer diol composition according to [1], wherein the monomer diol is a monomer diol produced by depolymerization of a polyester.

[0018]

[12] The monomer diol composition according to

[11] , wherein the polyester is a polyalkylene terephthalate.

[0019]

[13] The monomer diol composition according to

[12] , wherein the monomer diol is butanediol, ethylene glycol, bis(2-hydroxyethyl) terephthalate, or bis(4-hydroxybutyl) terephthalate, and the polyalkylene terephthalate is polybutylene terephthalate or polyethylene terephthalate.

[0020]

[14] The monomer diol composition according to any one of [1] to [6], wherein the monomer diol is butanediol produced using butadiene, butyne-1,4-diol, butane, or propylene oxide.

[0021]

[15] A method for producing a polyester, using the monomer diol composition according to any one of [1] to

[14] . [Effects of the Invention]

[0022] When the monomer diol composition of the present invention is subjected to a polymerization reaction as a polyester raw material, the time required for the latter stage of the polymerization reaction does not increase, and the yellowness of the resulting polyester can be kept low. Therefore, by using the monomer diol composition of the present invention, high-quality polyesters with little yellowing can be produced with excellent production efficiency. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following describes in detail the form of an embodiment of the present invention. However, the description of the constituent elements described below is an example of the form of an embodiment of the present invention, and the present invention is not limited to the contents of the following description as long as it does not go beyond the gist of the present invention. In this specification, when the expression "to" is used, it is intended to be used as an expression that includes the numerical values ​​or physical property values ​​before and after it. In this specification, "parts by weight" and "parts by mass" are synonymous, and "% by weight" and "% by mass" are synonymous. In the present invention, the "main component" of a dicarboxylic acid component refers to a component that accounts for 50 mol % or more of the dicarboxylic acid component. The same applies to the "main component" of a diol component. Furthermore, "ppm" refers to "ppm by mass" except for the unit of NMR chemical shift, which will be described later.

[0024] [Monomer diol composition] In the present invention, the monomer diol composition is characterized by containing a monomer diol. The monomer diol composition of the present invention may be in the form of a slurry of a mixture of solids and liquids, but is preferably a liquid.

[0025] The amount of monomer diol contained in the monomer diol composition of the present invention is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, since the monomer diol composition is used as a raw material for polyester. The monomer diol composition may also contain two or more types of monomer diol. The content of the second most abundant type of monomer diol is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less, relative to the first most abundant type of monomer diol. The monomer diol composition of the present invention may also contain only one type of monomer diol.

[0026] The monomer diol composition of the present invention may be a solution obtained by dissolving a monomer diol in a solvent such as water, methanol, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-(4-hydroxybutoxy)tetrahydrofuran, 2-hydroxytetrahydrofuran, 2,3-dihydrofuran, gamma-butyrolactam, 1,4-diacetoxybutane, 4-hydroxybutyraldehyde, 2-butene-1,4-diol, dimethyl succinate, diethyl succinate, etc. Since the monomer diol in the solution is also used as a raw material for polyester, the content of the monomer diol is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0027] [Monomer diol] Examples of the monomer diol include linear alkane diols, alkane diols having a cyclic structure, bisphenols (including bisphenol), and diesters of terephthalic acid and a monomer diol.

[0028] Examples of the linear alkanediol include linear alkanediols having 2 to 12 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, and dodecanediol. All of these linear alkanediols have the object of the present invention, and the object can be solved by the present invention. Among them, ethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, and 1,6-hexanediol are preferred.

[0029] Examples of alkanediols having a cyclic structure include cyclohexanedimethanol, cyclopentanediol, cyclohexanediol, bicyclohexanol, hydroxymethylcyclohexanol, hydroxyethylcyclohexanol, tetramethylcyclobutanediol, adamantanediol, 3-hydroxymethyl-1-adamantanol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)-3-methylphenyl]propane, 9,9'-bis[4-(2-hydroxyethoxy)phenyl]fluorene, and 9,9'-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene.

[0030] Examples of bisphenols include 2,2'-biphenol, 4,4'-biphenol, 1,5-naphthalenediol, 2,7-naphthalenediol, bis(4-hydroxyphenyl)methane (i.e., bisphenol F), bis{(4-hydroxy-3,5-dimethyl)phenyl}methane, 1,1-bis(4-hydroxyphenyl)ethane (i.e., bisphenol E), 1,1-bis(4-hydroxyphenyl)-1-phenylethane (i.e., bisphenol AP), 2,2-bis(4-hydroxyphenyl)hexafluoropropanediol, bis(4-hydroxyphenyl)-1-phenylethane ... propane (i.e., bisphenol AF), 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane (i.e., bisphenol C), 2,2-bis{(4-hydroxy-3,5-dimethyl)phenyl}propane, 2,2-bis{(3,5-dibromo-4-hydroxy)phenyl}propane, 2,2-bis{(3-isopropyl-4-hydroxy)phenyl}propane, 2,2-bis{(4-hydroxy-3-phenyl)phenyl}propane, 2 -(4-hydroxyphenyl)-2-(3-carboxy-4-hydroxyphenyl)propane, 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane, 1-(4-hydroxyphenyl)-1,3,3-trimethyl-5-hydroxyindan, 2-(4-hydroxyphenyl)-[3-{2-(4-hydroxyphenyl)propan-2-yl}-4-hydroxyphenyl]propane, 2,2-bis(4-hydroxyphenyl)butane (i.e., bisphenol B), 1,1-bis(4-hydroxyphenyl)-1,1-di Phenylmethane (i.e., bisphenol BP), 2,2-bis(4-hydroxy-3-isopropylphenyl)propane (i.e., bisphenol G), 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,Examples of such hydroxydiphenyl compounds include 1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis{(4-hydroxy-3-methyl)phenyl}fluorene, α,α'-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene, α,α'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 4,4'-dihydroxydiphenyl sulfone (i.e., bisphenol S), 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl ester.

[0031] Examples of diesters of terephthalic acid and monomer diols include bis(2-hydroxyethyl) terephthalate, a diester of terephthalic acid and ethylene glycol; bis(3-hydroxypropyl) terephthalate, a diester of terephthalic acid and 1,3-propylene glycol; bis(4-hydroxybutyl) terephthalate, a diester of terephthalic acid and 1,4-butanediol; and bis(4-hydroxymethylcyclohexylmethyl) terephthalate, a diester of terephthalic acid and cyclohexanedimethanol. These diesters can also be chemically recycled by depolymerization of polyesters such as polyethylene terephthalate and polybutylene terephthalate, and are therefore preferred as the monomer diols used in the present invention. These diesters of terephthalic acid and monomer diols are used as raw dicarboxylic acid components in the production of polybutylene terephthalate and polyethylene terephthalate.

[0032] All of these monomer diols have the object of the present invention, and the object can be solved by the present invention. Among them, monomer diols produced using biomass resources as raw materials and monomer diols produced by recycling waste products or defective products are preferred.

[0033] Furthermore, the monomer diol in the monomer diol composition of the present invention is preferably an alkanediol from the viewpoints of the efficiency of the polymerization-condensation reaction of the resulting polyester and the required mechanical properties of the resulting polyester, and the alkanediol is preferably one produced from biomass resources as raw materials or one produced by recycling waste products or defective products.

[0034] Alkanediols such as 1,4-butanediol produced using biomass resources as raw materials are preferably alkanediols produced by fermentation, such as alkanediols produced by direct fermentation of sugars and alkanediols produced by hydrogen reduction of succinic acid or succinic acid derivatives produced using biomass resources. Examples of succinic acid derivatives include succinic anhydride and succinic acid esters such as dialkyl succinates (more specifically, dialkyl succinates having an alkyl group with 1 to 4 carbon atoms, preferably 1 to 3, more preferably 1 to 2, and most preferably a methyl group with 1 carbon atom).

[0035] In the present invention, alkanediols such as 1,4-butanediol and ethylene glycol are preferred as monomer diols because they can be produced from biomass resources or by chemical recycling of waste products or defective products. For example, 1,4-butanediol can be produced by depolymerization of polybutylene terephthalate, and ethylene glycol can be produced by depolymerization of polyethylene glycol.

[0036] Of these, 1,4-butanediol is particularly preferably 1,4-butanediol produced using butadiene, butyne-1,4-diol, butane, or propylene oxide. That is, butadiene and acetic acid are oxidized to form diacetoxybutene, which is then hydrogenated to obtain diacetoxybutane, which is then hydrolyzed to produce 1,4-butanediol. In addition, acetylene and formaldehyde can be reacted to form propargyl alcohol, which can then be further reacted with formaldehyde to form butyne-1,4-diol, which can then be hydrogenated to produce 1,4-butanediol. In addition, butane can be oxidized to maleic anhydride, which is then hydrolyzed to obtain maleic acid, which can then be hydrogenated to produce 1,4-butanediol. Furthermore, propylene oxide can be isomerized to form allyl alcohol, which is then hydroformylated to form 4-hydroxybutyraldehyde, which can then be hydrogenated to produce 1,4-butanediol. These are all industrially produced, highly pure, and thermally stable, making them preferable.

[0037] Among the diesters of terephthalic acid and monomer diols described above, bis(2-hydroxyethyl) terephthalate is produced together with ethylene glycol during the depolymerization of polyethylene terephthalate, and bis(4-hydroxybutyl) terephthalate is produced together with 1,4-butanediol during the depolymerization of polybutylene terephthalate, and both are preferred as the monomer diols according to the present invention.

[0038] When the monomer diol contained in the monomer diol composition of the present invention is a monomer diol produced from a biomass resource or a monomer diol produced by recycling waste or defective products, it may contain an acid component, an alkali component, an oxidizing agent component, or a reducing agent component at or below the lower limit of analytical detection. The present invention is particularly effective for a monomer diol composition that may contain such components at or below the lower limit of analytical detection.

[0039] [Method of producing a monomer diol composition] The method for producing the monomer diol composition of the present invention is not particularly limited, and the composition can be produced by a conventional method, for example, by supplying a monomer diol to a preparation tank equipped with a heater and a stirrer, heating the mixture to a temperature equal to or higher than the melting point of the monomer diol, and then stirring and mixing the mixture to form a homogeneous solution, thereby obtaining the monomer diol composition. Since the monomer diol composition of the present invention is used as a raw material for polyester, the heating temperature is preferably 130° C. or higher, more preferably 140° C. or higher, and even more preferably 150° C. or higher. On the other hand, if the heating temperature is too high, the monomer diol in the monomer diol composition is distilled off, resulting in a decrease in the content of the monomer diol, so the heating temperature is preferably 350° C. or lower, particularly preferably 300° C. or lower.

[0040] [value (a / b) obtained by dividing the measured value a of the hydroxyl group amount of the monomer diol composition by the theoretical value b of the hydroxyl group amount of the monomer diol composition] The monomer diol composition of the present invention is characterized in that the value (a / b) (hereinafter sometimes simply referred to as the "a / b value") obtained by dividing the measured value a of the hydroxyl group amount measured by the following measurement method by the theoretical value b of the hydroxyl group amount is 0.980 or more and less than 1.000. <Measurement method> Step 1: Weighing the monomer diol composition to obtain the mass of the monomer diol composition Step 2: A step of obtaining a theoretical value b of the hydroxyl group amount of the monomer diol composition obtained in Step 1 using the mass of the monomer diol composition obtained in Step 1. Step 3: A step of measuring the monomer diol composition obtained in Step 1 by NMR to obtain a measured value a of the amount of hydroxyl groups in the monomer diol composition. Step 4: A step of obtaining a value (a / b) by dividing the measured value a of the amount of hydroxyl groups obtained in Step 3 by the theoretical value b of the amount of hydroxyl groups obtained in Step 2.

[0041] If the a / b value of the monomer diol composition of the present invention is small, the polymerization reaction rate will decrease when this monomer diol composition is used to produce a polyester. On the other hand, a monomer diol composition with a large a / b value contains a polyhydric alcohol such as a triol in the monomer diol composition, and polyesters obtained using such monomer diol compositions as raw materials will form gels with chemically crosslinked structures and will be significantly thickened. From this perspective, the a / b value of the monomer diol composition of the present invention is 0.980 or more and less than 1.000, preferably 0.985 or more and 0.997 or less, and more preferably 0.988 or more and 0.995 or less.

[0042] The a / b value of the monomer diol composition of the present invention can be determined, for example, by the following procedure. [Step 1] Accurately weigh out the monomer diol to c parts by mass. [Step 2] The monomer diol is heated to obtain a monomer diol composition. The heating temperature during this mixing is within the above-mentioned range, but is preferably equal to or higher than the melting point of the monomer diol in step 1. From the viewpoint of facilitating the monomer diol melting and becoming a homogeneous liquid, the temperature is preferably 50°C or more higher than the melting point and 20°C or more lower than the boiling point. The stirring time is preferably about 1 to 30 hours, for example, 1 hour. [Step 3] Using the parts by mass c of the monomer diol obtained in Step 1, the theoretical value e (mol / L) of the amount of hydroxyl groups per unit mass of the monomer diol composition is calculated. [Step 4] The monomer diol composition obtained in Step 2 and an internal standard substance (e.g., triphenylmethane (molecular weight: 244.33)) are weighed to mass f and mass g, respectively, in an NMR tube, and a deuterated solvent (e.g., deuterated chloroform) is supplied to obtain an NMR measurement solution. [Step 5] NMR of the NMR measurement solution obtained in Step 4 is measured, and the integral value of the peak derived from the hydroxyl groups of the monomer diol in the monomer diol composition and the integral value of the internal standard are calculated, and the integral value ratio h (=integral value of the peak derived from the hydroxyl groups of the monomer diol / integral value of the internal standard) is calculated. [Step 6] Using the formula below, calculate the measured value a of the hydroxyl group amount and the theoretical value b of the hydroxyl group amount, and calculate the a / b value by dividing the measured value a of the hydroxyl group amount by the theoretical value b of the hydroxyl group amount. a = (integral value ratio h × mass g) / molecular weight of internal standard substance b = theoretical value e of the amount of hydroxyl groups per unit mass of the monomer diol composition × mass f a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b

[0043] [Polyester manufacturing method] Examples of a method for producing a polyester of the present invention using the monomer diol composition of the present invention include a method in which the monomer diol composition of the present invention and a dicarboxylic acid component are subjected to an esterification or transesterification reaction in the presence of an esterification catalyst or a transesterification catalyst.

[0044] Hereinafter, a method for producing a polyester of the present invention will be described, mainly focusing on a method for producing polybutylene terephthalate (hereinafter sometimes abbreviated as "PBT") as a polyester, when the monomer diol composition of the present invention is a 1,4-butanediol composition containing 1,4-butanediol (hereinafter sometimes abbreviated as "BDO"). However, according to the method for producing a polyester of the present invention, it is possible to produce polyesters other than PBT, such as polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET"), in the same manner as the method described below, using a monomer diol composition of the present invention other than a 1,4-butanediol composition.

[0045] Hereinafter, the polyester produced by the polyester production method of the present invention may be referred to as "the polyester of the present invention", and the PBT produced by the polyester production method of the present invention may be referred to as "the PBT of the present invention".

[0046] PBT refers to a polymer having a structure in which a dicarboxylic acid component and a diol component are ester-bonded, in which 50 mol % or more of the dicarboxylic acid component is a terephthalic acid component, and 50 mol % or more of the diol component is BDO. The proportion of the terephthalic acid component in all dicarboxylic acid components is preferably 70 mol % or more, more preferably 80 mol % or more, and even more preferably 95 mol % or more, and the proportion of BDO in all diol components is preferably 70 mol % or more, more preferably 80 mol % or more, and even more preferably 95 mol % or more. If the terephthalic acid component or BDO is less than 50 mol %, the crystallization acceleration of the PBT decreases, resulting in poor moldability.

[0047] <Dicarboxylic acid component> In the present invention, the dicarboxylic acid component includes dicarboxylic acids and dicarboxylic acid derivatives. Of the monomer diol compositions of the present invention, those containing the above-mentioned diesters of terephthalic acid and a monomer diol as the monomer diol can be used as a raw material dicarboxylic acid component in the production of polyesters.

[0048] Examples of the terephthalic acid derivative include esters of terephthalic acid such as dimethyl terephthalate, and ester-forming derivatives such as terephthalic acid halide.

[0049] Dicarboxylic acids other than terephthalic acid that can be used as raw materials for producing PBT are not particularly limited, and examples include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Dicarboxylic acid derivatives include esters of these dicarboxylic acids and ester-forming derivatives such as dicarboxylic acid halides.

[0050] These dicarboxylic acid components other than the terephthalic acid component may be used alone or in combination of two or more. The terephthalic acid or terephthalic acid derivative in the present invention may be terephthalic acid or a terephthalic acid derivative produced from a fossil fuel, or may be terephthalic acid or a terephthalic acid derivative such as dimethyl terephthalate derived from a biomass resource, or may be chemically recycled terephthalic acid or a terephthalic acid derivative chemically recycled from waste products or defective products, for example, chemically recycled terephthalic acid or a terephthalic acid derivative such as dimethyl terephthalate produced by depolymerization of waste polyester such as waste polyethylene terephthalate or waste polybutylene terephthalate.

[0051] Dicarboxylic acid components such as succinic acid may also be derived from biomass or chemically recycled.

[0052] <Diol component> In the method for producing a polyester of the present invention, the monomer diol composition of the present invention is used as the diol component. However, as described above, a monomer diol composition containing a diester of terephthalic acid and a monomer diol as the monomer diol is used as the raw material dicarboxylic acid component.

[0053] <Other ingredients> In the present invention, one or more of the following copolymerization components can be used in the production of PBT: hydroxycarboxylic acids such as lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, and p-β-hydroxyethoxybenzoic acid; monofunctional components such as stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, and benzoylbenzoic acid; and trifunctional or higher polyfunctional components such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, and pentaerythritol.

[0054] The polyester of the present invention may also be a PTMG copolymerized PBT in which crystalline PBT is used as a hard segment and polytetramethylene ether glycol (hereinafter, sometimes referred to as "PTMG") is used as a soft segment. The PTMG copolymerized PBT can be obtained by subjecting a dicarboxylic acid component containing terephthalic acid as the main component, a diol component containing the butanediol composition of the present invention and PTMG, and further other components used as necessary, to an esterification reaction and / or an ester exchange reaction, followed by a polycondensation reaction, and preferably further a solid-state polycondensation reaction.

[0055] In this case, the number average molecular weight of the PTMG used is preferably 650 to 2000, more preferably 800 to 1500. When the molecular weight is within this range, the reactivity during production of the PTMG copolymerized PBT is good, the degree of melting point depression due to copolymerization is small, and a PTMG copolymerized PBT with good mechanical properties can be obtained. The molecular weight of the PTMG is controlled by the reaction temperature, reaction time, catalyst amount, etc. during production of the PTMG. Furthermore, the lower limit of the copolymerization amount of the PTMG component in the PTMG copolymerized PBT is preferably 8 mass%, more preferably 10 mass%, and even more preferably 15 mass%, and the upper limit is preferably 35 mass%, more preferably 30 mass%, and even more preferably 25 mass%.

[0056] Here, the copolymerization amount (content) of PTMG refers to the proportion of PTMG units as a diol component in the PTMG-copolymerized PBT, i.e., the proportion of the amount of the component obtained by subtracting the amount of water molecules resulting from ester bond formation from PTMG, relative to the PTMG-copolymerized PBT, expressed in mass %. By ensuring that the copolymerization ratio of PTMG is within this range, a PTMG copolymerized PBT with a good balance of flexibility and impact strength can be obtained. The amount of PTMG copolymerized can be controlled by the amount of PTMG charged during the production of the copolymerized PBT.

[0057] <Polyester manufacturing method> The method for producing the polyester of the present invention is not particularly limited, and the production method may be a continuous method or a batch method. The polyester of the present invention can be produced by a conventional method, for example, through a step of mixing, under stirring, a dicarboxylic acid component mainly composed of terephthalic acid or a terephthalate ester and a diol component mainly composed of the monomer diol composition of the present invention in a predetermined ratio to obtain an ester raw material liquid, a step of heating the ester raw material liquid under normal pressure or reduced pressure to cause an esterification reaction or an ester exchange reaction (hereinafter collectively referred to as an "ester (exchange) reaction") to obtain a polyester oligomer, and a melt polycondensation step of gradually reducing the pressure and heating the obtained oligomer to cause a melt polycondensation reaction to obtain a polyester. As described above, the method for producing the polyester of the present invention is not limited, but an example thereof includes a production method via the following ester (transfer) reaction step and polycondensation reaction step.

[0058] (Transesterification reaction step) An example of a process for first subjecting a starting material terephthalic acid or terephthalate ester to an ester (exchange) reaction with the monomer diol composition of the present invention to produce an oligomer is a method in which, using a single ester (exchange) reaction tank or a multistage reaction apparatus in which a plurality of ester (exchange) reaction tanks are connected in series, the ester (exchange) reaction is carried out under normal or reduced pressure with or without a catalyst until the ester (exchange) reaction rate (the proportion of all carboxyl groups or all ester groups in the starting dicarboxylic acid component that have reacted with the diol component and undergone an ester (exchange) reaction) reaches typically 90% or more, while removing water or alcohol produced in the reaction and excess diol component from the system, to obtain an oligomer. Typically, the temperature of the ester (transfer) reaction is about 210 to 230°C, the pressure is about 10 to 133 kPa, and the residence time in the reaction tank, which corresponds to the reaction time, is about 1 to 4 hours.

[0059] (Polycondensation reaction step) An example of the polycondensation reaction step is a method in which a single melt polycondensation tank or a multistage reaction apparatus in which a plurality of melt polycondensation tanks are connected in series, for example, a first-stage reactor is a complete mixing type reactor equipped with stirring blades, and second-stage and third-stage reactors are horizontal plug flow type reactors equipped with stirring blades, is used, and the diol produced is distilled out of the system while heating under reduced pressure in the presence of a catalyst. Generally, the polycondensation reaction is carried out at a temperature of 210 to 280°C, preferably about 220 to 250°C, under reduced pressure of 27 kPa or less, preferably 13 kPa or less.

[0060] The reaction tank may be a single tank or multiple tanks. However, in order to prevent coloration and deterioration and to suppress an increase in terminal groups such as vinyl groups, it is advisable to carry out the reaction in at least one reaction tank under a high vacuum of usually 1.3 kPa or less, preferably 0.3 kPa or less.

[0061] The polyester obtained by the polycondensation reaction is usually withdrawn in the form of a strand or sheet from a withdrawal port provided at the bottom of the polycondensation reaction tank, and then cut with a cutter while or after water cooling to form granular bodies such as pellets or chips (for example, lengths of about 3 to 10 mm). Alternatively, the molten resin is released from the polycondensation reaction tank through a pipe into cold water adjusted to a predetermined temperature, and then cut with a cutter to form spheres (diameters of about 2 to 10 mm).

[0062] <Polycondensation catalyst> When polycondensing an oligomer obtained by an ester (exchange) reaction between a diol component and a dicarboxylic acid component, a titanium compound and preferably a compound of a metal of Group 2A of the Periodic Table are usually used as catalysts. These catalyst components may be used in the ester (exchange) reaction and then directly subjected to the polycondensation reaction, or they may not be used in the ester (exchange) reaction, or only the titanium catalyst may be used, with the remaining catalyst components added at the polycondensation stage. Furthermore, a portion of the catalyst amount ultimately used may be used in the ester (exchange) reaction, and then appropriately added as the polycondensation reaction proceeds. In any case, in the present invention, titanium and preferably also a metal of Group 2A of the Periodic Table are inevitably contained in the polyester finally obtained. The content thereof will be described later.

[0063] (Example of titanium compounds) Specific examples of titanium compounds used as catalysts include inorganic titanium compounds such as titanium oxide and titanium tetrachloride, tetraalkyl titanates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, and tetraaryl titanates such as tetraphenyl titanate. These may be used alone or in combination of two or more. Of these, tetraalkyl titanates are preferred, and among these, tetrabutyl titanate is preferred.

[0064] (titanium catalyst amount) The content of the titanium catalyst in the polyester of the present invention is preferably 5 to 200 ppm by mass of titanium atoms relative to the polyester. This amount is more preferably 10 ppm or more, even more preferably 20 ppm or more, and most preferably 25 ppm or more. This amount is more preferably 190 ppm or less, even more preferably 180 ppm or less, particularly preferably 170 ppm or less, particularly preferably 160 ppm or less, and most preferably 150 ppm or less. If the titanium content is too high, problems arise such as deterioration in color tone, hydrolysis resistance, and solution haze, and an increase in fish eyes in the resulting molded product, while if the titanium content is too low, polymerization properties deteriorate.

[0065] (Group 2A metal compound) Specific examples of the Group 2A metal compound of the periodic table used as a catalyst include various compounds of beryllium, magnesium, calcium, strontium, and barium. From the viewpoints of ease of handling and availability, and catalytic effect, magnesium compounds and / or calcium compounds are preferred, and magnesium compounds, which have excellent catalytic effect, are particularly preferred.

[0066] Specific examples of magnesium compounds include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Specific examples of calcium compounds include calcium acetate, calcium hydroxide, calcium carbonate, calcium oxide, calcium alkoxide, and calcium hydrogen phosphate.

[0067] These Group 2A metal compounds of the periodic table may be used alone or in combination of two or more. Of these, magnesium acetate is preferred.

[0068] (Group 2A metal catalyst amount) The content of the Group 2A metal catalyst in the polyester of the present invention is not particularly limited, but is preferably 3 to 150 ppm by mass relative to the polyester in terms of Group 2A metal atoms. This amount is more preferably 5 ppm or more, and even more preferably 10 ppm or more. This amount is more preferably 140 ppm or less, even more preferably 130 ppm or less, and particularly preferably 100 ppm or less. If the content of the Group 2A metal is too high, color tone and hydrolysis resistance will deteriorate, while if it is too low, polymerization will deteriorate.

[0069] When an acetate of a metal of Group 2A of the Periodic Table is used, the amount of the metal of Group 2A of the Periodic Table in the polyester is preferably 100 ppm or less, since the acetic acid source enters the reaction system.

[0070] (M / Ti ratio) The molar ratio of titanium atoms to Group 2A metal atoms of the periodic table (Group 2A metal atoms of the periodic table / titanium) contained in the polyester of the present invention is usually 0.01 to 100, preferably 0.1 to 10, more preferably 0.3 to 3, and even more preferably 0.3 to 1.5.

[0071] (Metal analysis method) The content of metals such as titanium atoms in polyester can be measured using methods such as atomic emission, atomic absorption, and ICP emission after recovering the metals in the polymer by a method such as wet ashing.

[0072] (Other catalysts) In producing the polyester of the present invention, in addition to the titanium compound and the compound of a metal of Group 2A of the Periodic Table, reaction aids such as antimony compounds such as antimony trioxide, germanium compounds such as germanium dioxide and germanium tetroxide, manganese compounds, zinc compounds, zirconium compounds, cobalt compounds, phosphorus compounds such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, esters or metal salts thereof, sodium hydroxide, sodium benzoate, etc. may be used.

[0073] [Intrinsic viscosity of PBT] When the PBT of the present invention is used for compounding or injection molding, the intrinsic viscosity of the PBT is preferably 0.6 to 1.3 dL / g. If the intrinsic viscosity is less than 0.6 dL / g, the mechanical strength of the molded product tends to be insufficient, while if it exceeds 1.3 dL / g, the melt viscosity tends to be high, which deteriorates the flowability and moldability. The intrinsic viscosity of the PBT of the present invention is more preferably 0.65 to 1.26 dL / g, and even more preferably 0.7 to 1.2 dL / g.

[0074] Furthermore, when the PBT pellets of the present invention are used for extrusion applications such as film, sheet, or filament, the intrinsic viscosity of the PBT is usually 1.00 to 1.60 dL / g, preferably 1.03 to 1.50 dL / g, more preferably 1.05 to 1.55 dL / g, particularly preferably 1.10 to 1.50 dL / g, and particularly preferably 1.15 to 1.35 dL / g. If the intrinsic viscosity is less than 1.00 dL / g, extrusion moldability deteriorates, leading to drawdown of the resin and molding defects, resulting in insufficient mechanical strength of extrusion-molded products such as films, or the melt viscosity decreases, resulting in excessively high fluidity and thus poor extrusion moldability. On the other hand, if the intrinsic viscosity exceeds 1.60 dL / g, the melt viscosity increases, resulting in poor fluidity and thus poor extrusion moldability.

[0075] [Compound] The polyester of the present invention is produced with excellent polymerization reaction efficiency and good productivity using the monomer all composition of the present invention, and is excellent in color tone with suppressed yellowing. The polyester of the present invention can be compounded into a compound product by adding various additives or compounding materials as required during or after the polyester production stage. [Example]

[0076] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0077] [Raw materials and reagents] Dimethyl terephthalate and tetrabutyl titanate were reagents manufactured by Tokyo Chemical Industry Co., Ltd. The deuterated chloroform used was a reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., which was prepared by immersing molecular sieves 4A manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., which had been previously dehydrated under reduced pressure in an oil bath at 200°C for 3 hours, and then drying the chloroform. The petroleum-derived 1,4-butanediol used was a product of Mitsubishi Chemical Corporation. The internal standard substance for NMR, triphenylmethane, was a reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Furthermore, "ADEKA STAB AO-60" manufactured by ADEKA Corporation was used as a phenolic antioxidant. Terephthalic acid (high-purity terephthalic acid, hereinafter referred to as "PTA") is a refined TPA produced through the following two steps. Step 1: Paraxylene is mixed with acetic acid and a catalyst, and air is blown into it under high temperature and pressure conditions to obtain crude TPA. Step 2: The crude "TPA" obtained in Step 1 is purified to obtain purified TPA. Terephthalic acid (single-step oxidation method, hereinafter referred to as "QTA") is the crude TPA obtained in step 1 above.

[0078] [Evaluation method] The a / b value was calculated by determining the measured value a of the hydroxyl group amount and the theoretical value b of the hydroxyl group amount according to the following procedures 1 to 6, and dividing the measured value a of the hydroxyl group amount by the theoretical value b of the hydroxyl group amount. [Step 1] The monomer diol was precisely weighed out to c parts by mass. [Step 2] The monomer diol obtained in step 1 was heated to obtain a monomer diol composition. [Step 3] Using the parts by mass c of the monomer diol obtained in Step 1, the theoretical value e (mol / g) of the amount of hydroxyl groups per unit mass of the monomer diol composition was calculated. [Step 4] The monomer diol composition obtained in Step 2 and triphenylmethane (molecular weight: 244.33) as an internal standard were weighed in masses f and g, respectively, into an NMR tube, and deuterated chloroform was added to obtain an NMR measurement solution. ​[Step 5] NMR of the NMR measurement solution obtained in Step 4 is measured, and the sum of the integral values ​​of the peaks derived from the hydroxyl groups of the monomer diol composition and the integral value of the peaks derived from the internal standard triphenylmethane (Ph3C- H ) was calculated, and the integral ratio h (integral value of the peak derived from the hydroxyl group of the monomer diol / integral value of triphenylmethane) was calculated. In addition, nuclear magnetic resonance ( 1 1 H NMR measurements were carried out using a Bruker Advance NEO600 spectrometer under the following conditions: (NMR measurement conditions) Flip angle: 45° Data acquisition time: 3 seconds Pulse repetition time: 10 seconds Accumulation count: 512 ·Temperature: 25℃ [Step 6] The measured value a of the hydroxyl group amount and the theoretical value b of the hydroxyl group amount were calculated using the following formula, and the measured value a of the hydroxyl group amount was divided by the theoretical value b of the hydroxyl group amount to calculate the a / b value. a = (integral value ratio h × mass g) / molecular weight of internal standard substance (244.33) b = theoretical value e of the amount of hydroxyl groups per unit mass of the monomer diol composition × mass f a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b

[0079] <Analysis of 1,4-butanediol and ethylene glycol> Analysis of 1,4-butanediol and ethylene glycol was carried out by gas chromatography using the following equipment and conditions. Equipment: Shimadzu GC-2014 Column: Agilent Technologies "DB-1" (inner diameter 0.53 mm, column length 30 m, film thickness 1 μm) Carrier gas: Helium Carrier gas flow rate: 5.58 cm per minute 3 Linear speed: 47.4 cm per second ·Inlet temperature: 250℃ Detector temperature: 280℃ Column temperature rise pattern: First, hold at 150°C for 5 minutes, then raise the temperature at 13°C per minute to 295°C, and hold at 295°C for 15 minutes for analysis.

[0080] <Residual rate of dimethyl terephthalate> The residual rate of dimethyl terephthalate was measured by high performance liquid chromatography using the following apparatus and conditions. Apparatus: Shimadzu high performance liquid chromatography Pump: LC-20AD Column oven: CTO-20AC Detector: SPD-20A Column: CAPCELL PAK C18, TYPE MGII 5 μm, 4.6 mm ID x 150 mm Method: Low-pressure gradient method ·Analysis temperature: 40℃ ·Eluent composition: I liquid: water Solution II: Acetonitrile For analysis times of 0 to 10 minutes, the eluent composition was I:II = 50:50 (volume ratio, same below), gradually changed to I:II = 100:0 for analysis times of 10 to 20 minutes, and then I:II = 100:0 for analysis times of 20 to 30 minutes. ·Flow rate: 0.8mL / min Detection wavelength: 254nm

[0081] <Intrinsic viscosity> The viscosity was measured using a fully automatic viscosity measuring device (model DT553, capillary type) manufactured by Sentec Co., Ltd. in the following manner. A mixed solution of phenol and 1,1,2,2-tetrachloroethane (1 / 1 mass ratio mixture) was used as the solvent. The number of seconds it took for a 1.0 g / dL PBT sample solution and the solvent alone to fall at 30°C was measured and calculated using the following formula. Intrinsic viscosity (dL / g)=((1+4KHη3) 0.5 -1) / (2K H C) (Here, η3 = η / η0-1, η is the number of seconds for the sample solution to fall, η0 is the number of seconds for the solvent to fall, C is the PBT concentration of the sample solution (g / dL), K H is Huggins' constant. KH adopted 0.33.)

[0082] <Tone of PBT and PET> The tone of PBT and PET was evaluated in the Lab color system using a color difference meter "Z-300A type" manufactured by Nippon Denshoku Industries Co., Ltd. The lower the b value, the less yellowish it is and the more preferable. However, when the b value is lower than -2.0, although the yellowishness is less, the bluishness increases and the tone is not preferable. The evaluation criteria for the b value were as follows. S: -1.0 ≤ b value ≤ 2.0 A: b value < -1.0 or 2.0 < b value ≤ 2.5 B: 2.5 < b value ≤ 3.0 C: 3.0 < b value

[0083] [Production Example of BDO] [Production Example 1: BDO Produced by Hydrogenation Reaction of Biomass Succinic Acid] 1,4-butanediol manufactured by Yuanli Chemical Group Co., Ltd. and 1,4-butanediol manufactured by Zhejiang Boju New Materials Co., Ltd., which were produced by hydrogenation of succinic acid derived from biomass resources, were mixed to obtain a mixed solution. The obtained mixed solution was distilled under reduced pressure, and from the order of distillation, a first fraction, a main fraction A, a main fraction B, a main fraction C, a main fraction D, and a residue were obtained. When a part was extracted from each of the main fraction A, the main fraction B, the main fraction C, the main fraction D, and the residue and analyzed by gas chromatography, the 1,4-butanediol content was 99% by mass or more in all cases.

[0084] [Production Example 2: BDO Produced by Depolymerization of Polybutylene Terephthalate] The butanediol obtained by chemical recycling was produced following Example 3 of JP-A-2004-323378. 1030 parts by mass of polyethylene terephthalate, 3200 parts by mass of methanol, and 13 parts by mass of sodium carbonate were supplied to an autoclave equipped with a stirring blade. The autoclave was immersed in an oil bath at 200 °C and reacted with stirring at a pressure of 1.3 MPa for 8 hours. The autoclave was taken out of the oil bath and cooled to 10 °C or lower with ice water to obtain a slurry solution. The resulting slurry was subjected to solid-liquid separation using filter paper to obtain a filtrate. The filtrate was placed in a distillation apparatus equipped with a thermometer, a pressure reduction controller, a stirring blade, a condenser, and a distillate receiver. After recovering methanol and tetrahydrofuran as the initial fraction, the mixture was distilled under reduced pressure to obtain the initial fraction, main fraction A, main fraction B, main fraction C, main fraction D, and subsequent fractions in the order of distillation. A portion of the obtained main fractions A to D was extracted and analyzed by gas chromatography, and it was found that the 1,4-butanediol content was 99% by mass or more.

[0085] [Production example of ethylene glycol] <Production Example 3: Ethylene glycol produced by depolymerization of polyethylene terephthalate> Ethylene glycol obtained by chemical recycling was produced in accordance with Example 2 of JP-A-2004-323378. 1,030 parts by mass of polyethylene terephthalate, 3,200 parts by mass of methanol, and 13 parts by mass of sodium carbonate were fed to an autoclave equipped with a stirring blade. The autoclave was immersed in an oil bath at 200°C, and the mixture was allowed to react while stirring at a pressure of 1.3 MPa for 8 hours. The autoclave was removed from the oil bath and cooled to below 10°C with ice water to obtain a slurry. The obtained slurry was subjected to solid-liquid separation using filter paper to obtain a filtrate. The obtained filtrate was placed in a distillation apparatus equipped with a thermometer, a pressure reduction controller, a stirring blade, a condenser, and a fraction receiver. Methanol and tetrahydrofuran were recovered as the initial fraction, and then distilled under reduced pressure to obtain the initial fraction, main fraction A, main fraction B, main fraction C, main fraction D, and subsequent fractions in the order of distillation. A portion of the obtained main fractions A to D was extracted and analyzed by gas chromatography, and it was found that the ethylene glycol content was 99% by mass or more.

[0086] <Production Example 4: Ethylene glycol produced from bioresources> γ-alumina (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was pulverized using a ball mill and then sieved to a size of 250-500 μm to obtain 1 g of γ-alumina catalyst. 1 g of the resulting alumina catalyst was packed into a flow-type tubular reactor with an inner diameter of 25 mm. The atmosphere inside the reactor was replaced with argon, and the temperature was raised to 360°C. A mixture of 24 g of pure water and 276 g of bioethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was fed into the reactor at a rate of 1.5 ml per hour to obtain bioethylene. Using the obtained bioethylene, a mixed gas containing 30% by volume of bioethylene, 0.4% by volume of methane, 11.1% by volume of nitrogen, 8.5% by volume of oxygen, 50% by volume of carbon dioxide, and 3 ppm by volume of chlorobenzene was obtained. The obtained mixed gas was introduced into a 7.5 mm inner diameter tubular reactor heated to 290°C and packed with an α-alumina catalyst supporting silver, cesium, lithium, and barium prepared according to Example 1 of JP-A-9-150058, at a space velocity of 4300 h -1 The oxygen was supplied at a reaction pressure of 0.8 MPa. The reaction temperature was adjusted so that the oxygen conversion rate was 40%. The reaction gas obtained from the reactor was passed through a trap at -40°C to obtain crude bioethylene oxide. The trap containing the obtained crude bioethylene oxide was connected to a distillation column equipped with a cooling device, a thermometer, and a fractional distillation receiver, and the temperature of the trap was gradually raised to obtain the initial fraction, bioethylene oxide, in the order in which it was distilled. 100 g of the obtained bioethylene oxide and 600 g of water were placed in an autoclave equipped with a thermometer and a stirring blade. The mixture was then heated to 110°C and reacted for 5 hours with stirring, and then cooled to room temperature to obtain a hydrolysis reaction solution. Water was distilled from the obtained hydrolysis reaction solution using an evaporator equipped with an oil bath to obtain a concentrated solution. The concentrated solution was placed in a distillation apparatus equipped with a thermometer, a pressure reduction controller, a stirring blade, a cooling tube, and a fraction receiver. Water and ethylene glycol were recovered as the initial fraction, and then distilled under reduced pressure to obtain the initial fraction, main fraction A, main fraction B, main fraction C, main fraction D, and subsequent fractions in the order of distillation. Portions of the obtained main fractions A to D were extracted and analyzed by gas chromatography, and it was found that the ethylene glycol content in each was 99% by mass or more.

[0087] [Example of chemically recycled dimethyl terephthalate production] <Production Example 5: Chemically Recycled Dimethyl Terephthalate A> Chemically recycled dimethyl terephthalate A was obtained with reference to the method described in JP-A-2001-151934. An autoclave equipped with a stirrer and a thermometer was charged with 100 parts by weight of glass filler-containing polybutylene terephthalate and 200 parts by weight of methanol. The autoclave was immersed in an oil bath at 170°C and reacted at 5.5 MPa for 5 hours. The autoclave was then removed from the oil bath and cooled to room temperature to obtain depolymerization reaction solution 1. The resulting depolymerization reaction solution 1 was filtered through a glass filter to obtain a solid fraction. Tetrahydrofuran was added to the resulting solid fraction to dissolve solid 1 contained in the solid fraction. The glass filler was removed as a filtrate by filtration to obtain solution 1. Toluene was added to the resulting solution 1 to obtain solution 2. The resulting solution 2 was placed in a flask equipped with a fraction collection receiver, a stirrer, and a thermometer and then immersed in an oil bath. The oil bath was set to 90°C, and tetrahydrofuran was distilled from solution 2. The flask was then cooled to room temperature to obtain slurry 1. The resulting slurry 1 was subjected to solid-liquid separation using a centrifuge to obtain solid 2. The obtained solid 2 was placed in a flask equipped with a fraction recovery receiver, a stirrer, and a thermometer, and the temperature and pressure of the oil bath were then controlled to obtain, in the order of distillation, low-boiling components containing toluene, main fraction A, main fraction B, and bottoms. A portion of the obtained main fraction B (chemically recycled dimethyl terephthalate A) was extracted and analyzed by gas chromatography, revealing that the dimethyl terephthalate content was 99% by mass or more.

[0088] <Production Example 6: Chemically Recycled Dimethyl Terephthalate B> Chemically recycled dimethyl terephthalate B was obtained with reference to the method described in JP-A-2004-323378. An autoclave equipped with a stirrer and a thermometer was charged with 100 parts by mass of polyethylene terephthalate waste fiber, 300 parts by mass of methanol, and 1.5 parts by mass of sodium carbonate. The autoclave was immersed in an oil bath at 150°C, and the reaction was carried out at 1.3 MPa for 10 hours. Thereafter, a distillation tube was attached to the autoclave, and the pressure was slowly reduced to normal pressure to distill off low-boiling components, thereby obtaining depolymerization reaction solution 1. After the temperature of the obtained depolymerization reaction liquid 1 was lowered to room temperature, xylene was added, and the mixture was immersed in an oil bath at 120°C to obtain slurry 1. The obtained slurry 1 was filtered through a glass filter, cooled to room temperature, and crystallized to obtain slurry 2. The obtained slurry 2 was subjected to solid-liquid separation using a centrifuge to obtain a cake. The obtained cake was placed in a flask equipped with a fraction collection receiver, a stirrer, and a thermometer, and then immersed in an oil bath. The temperature and pressure of the oil bath were controlled while monitoring the distillate, and the initial fraction, main fraction, and bottoms were obtained in the order of distillation. A portion of the obtained main fraction (chemically recycled dimethyl terephthalate B) was extracted and analyzed by gas chromatography, and the dimethyl terephthalate content was found to be 99% by mass or more.

[0089] <Production Example 7: Chemically Recycled Dimethyl Terephthalate C> Chemically recycled dimethyl terephthalate was obtained with reference to the method described in JP-A-2001-151934. A flask equipped with a fraction recovery receiver, a stirrer, and a thermometer was charged with 100 parts by mass of polyethylene terephthalate waste fiber, 400 parts by mass of ethylene glycol, and 1.5 parts by mass of sodium carbonate. The flask was immersed in an oil bath at 210°C, and the mixture was reacted for 10 hours while removing low-boiling components, yielding a depolymerization reaction solution 1. The resulting depolymerization reaction solution 1 was filtered while hot using a glass filter, yielding a filtrate 1. The obtained filtrate 1 was cooled to 25°C to obtain a slurry. The obtained slurry was subjected to solid-liquid separation using a centrifuge to obtain a crude wet cake. The obtained wet cake was washed by sprinkling ethylene glycol, and then subjected to solid-liquid separation using a centrifuge to obtain a purified wet cake. A portion of the obtained purified wet cake was extracted and analyzed by gas chromatography, and the content of bis(2-hydroxyethyl) terephthalate was found to be 90 mass% or more. 90 parts by mass of the purified wet cake containing the obtained bis(2-hydroxyethyl) terephthalate, 200 parts by mass of methanol, and 0.5 parts by mass of sodium carbonate were added to a flask equipped with a fraction recovery receiver, a stirrer, and a thermometer, and the mixture was reacted at 65°C for 1 hour to obtain reaction liquid 1. The resulting reaction liquid 1 was placed in a vacuum distillation apparatus equipped with a fraction collection receiver, a Liebig condenser, a stirrer, a thermometer, and a pressure controller. The distillation apparatus was immersed in an oil bath, and the temperature and pressure of the oil bath were controlled while monitoring the distillate. The initial fraction, main fraction, and bottoms were obtained in the order of distillation. The resulting main fraction and xylene were placed in an eggplant flask and heated to form a homogeneous solution. The solution was then cooled to room temperature for crystallization, yielding Slurry 1. The resulting Slurry 1 was filtered through a glass filter to obtain a cake. The resulting cake was placed in an eggplant flask and attached to an evaporator equipped with an oil bath. The xylene was distilled off from the cake under reduced pressure, yielding a white solid (chemically recycled dimethyl terephthalate C). A portion of the resulting white solid was extracted and analyzed by gas chromatography. The dimethyl terephthalate content was found to be 99% by mass or more.

[0090] [Example of chemically recycled terephthalic acid production] <Production Example 8: Chemically Recycled Terephthalic Acid A> In the same manner as in Production Example 5, a white solid of dimethyl terephthalate (chemically recycled dimethyl terephthalate A) having a dimethyl terephthalate content of 99 mass % or more was obtained. The resulting white solid of dimethyl terephthalate was dissolved in methylene chloride, and a methanol solution of potassium hydroxide was added thereto for hydrolysis, yielding reaction solution 1. The resulting reaction solution 1 was neutralized with 60% by mass of sulfuric acid to yield slurry 2. The resulting slurry 2 was filtered using a centrifuge to yield cake 2. The resulting cake 2 was added to pure water and mixed to yield slurry 3. The resulting slurry 3 was filtered using a centrifuge to yield cake 3. The resulting cake 3 was again added to pure water and mixed to yield slurry 4. The resulting slurry 4 was filtered using a centrifuge to yield cake 4. The resulting cake 4 was placed in an eggplant flask and attached to an evaporator equipped with an oil bath. Low-boiling components were distilled off from cake 4 under reduced pressure, yielding a white solid. A portion of the resulting white solid (chemically recycled terephthalic acid A) was analyzed by high-performance liquid chromatography, and the terephthalic acid content was found to be 99% by mass or more.

[0091] <Production Example 9: Chemically Recycled Terephthalic Acid B> In the same manner as in Production Example 6, a main fraction (chemically recycled dimethyl terephthalate B) having a dimethyl terephthalate content of 99 mass % or more was obtained. Instead of the white solid of chemically recycled dimethyl terephthalate A, the main fraction of this dimethyl terephthalate (chemically recycled dimethyl terephthalate B) was used, and hydrolysis and purification were carried out in the same manner as in Production Example 9 to obtain a white solid (chemically recycled terephthalic acid B) having a terephthalic acid content of 99% by mass or more.

[0092] <Production Example 10: Chemically Recycled Terephthalic Acid C> In the same manner as in Production Example 7, a main fraction (chemically recycled dimethyl terephthalate C) having a dimethyl terephthalate content of 99 mass % or more was obtained. Instead of the white solid of chemically recycled dimethyl terephthalate A, the main fraction of this dimethyl terephthalate (chemically recycled dimethyl terephthalate C) was used, and hydrolysis and purification were carried out in the same manner as in Production Example 9 to obtain a white solid (chemically recycled dimethyl terephthalate C) having a terephthalic acid content of 99% by mass or more.

[0093] <Production Example 11: Chemically Recycled Terephthalic Acid D> A white solid containing bis(2-hydroxyethyl) terephthalate in an amount of 99% by mass or more was obtained in the same manner as in Production Example 13 described below. Instead of the white solid of chemically recycled dimethyl terephthalate A, the obtained bis(2-hydroxyethyl) terephthalate was used, and hydrolysis and purification were carried out in the same manner as in Production Example 9 to obtain a white solid (chemically recycled terephthalic acid D) having a terephthalic acid content of 99% by mass or more.

[0094] <Production Example 12: Chemically Recycled Terephthalic Acid E> 200 parts by mass of polybutylene terephthalate and 800 parts by mass of butanediol were placed in an autoclave equipped with a thermometer and a stirrer. The autoclave was immersed in an oil bath at 170°C, and the mixture was allowed to react for 5 hours to obtain a depolymerization reaction liquid. The obtained depolymerization reaction liquid was cooled to room temperature, and toluene was added thereto to obtain slurry 1. The obtained slurry 1 was subjected to solid-liquid separation using a centrifuge to obtain cake 1. A portion of the obtained cake was analyzed by high-performance liquid chromatography, and the content of bis(4-hydroxybutyl) terephthalate was found to be 90% by mass or more. The resulting cake, bis(4-hydroxybutyl) terephthalate and toluene, was placed in a flask equipped with a thermometer and a stirrer and heated to 80°C to dissolve. A methanol solution of potassium hydroxide was added thereto for hydrolysis, yielding reaction solution 1. The resulting reaction solution 1 was cooled to room temperature and neutralized with 60% by mass of sulfuric acid to yield slurry 2. The resulting slurry 2 was filtered using a centrifuge to yield cake 2. The resulting cake 2 was added to pure water and mixed to yield slurry 3. The resulting slurry 3 was filtered using a centrifuge to yield cake 3. The resulting cake 3 was again added to pure water and mixed to yield slurry 4. The resulting slurry 4 was filtered using a centrifuge to yield cake 4. The resulting cake 4 was placed in an eggplant flask and attached to an evaporator equipped with an oil bath. Low-boiling components were distilled off from cake 4 under reduced pressure, yielding a white solid. A portion of the resulting white solid (chemically recycled terephthalic acid E) was analyzed by liquid chromatography, revealing that the terephthalic acid content was 99% by mass or more.

[0095] [Production example of chemically recycled bis(2-hydroxyethyl) terephthalate] <Production Example 13: Chemically Recycled 2-Hydroxyethyl Terephthalate> Chemically recycled bis(2-hydroxyethyl) terephthalate was obtained with reference to the method described in JP-A-2001-151934. A flask equipped with a fraction collection receiver, stirrer, and thermometer was charged with 100 parts by mass of polyethylene terephthalate waste fiber, 400 parts by mass of ethylene glycol, and 1.5 parts by mass of sodium carbonate. The flask was immersed in an oil bath at 210°C, and the reaction was allowed to proceed for 10 hours while removing low-boiling components, yielding depolymerization reaction solution 1. The resulting depolymerization reaction solution 1 was hot filtered through a glass filter to yield filtrate 1. The resulting filtrate 1 was cooled to 25°C to yield slurry 1. The resulting slurry 1 was subjected to solid-liquid separation using a centrifuge to obtain a crudely purified wet cake. The resulting wet cake was washed by spraying ethylene glycol on it, and then subjected to solid-liquid separation using a centrifuge to obtain a crude wet cake. The resulting purified wet cake was placed in a flask equipped with a thermometer and stirrer, and toluene was added to obtain slurry 2. The resulting slurry 2 was heated to 80°C, stirred for 2 hours, and then cooled to room temperature. Solid-liquid separation was then performed using a centrifuge to obtain a purified wet cake. The obtained purified wet cake was placed in a recovery flask, attached to an evaporator equipped with an oil bath, and dried under reduced pressure to obtain a white solid (chemically recycled bis(2-hydroxyethyl) terephthalate). A portion of the obtained white solid was extracted and analyzed by gas chromatography, and the content of bis(2-hydroxyethyl) terephthalate was found to be 99% by mass or more.

[0096] [Biomass resource BDO and reagent dimethyl terephthalate] [Example 1] 102.3 g (mass c) of the main fraction B obtained in Production Example 1 was placed in a recovery flask equipped with a stirrer. The recovery flask was then immersed in an oil bath heated to 150°C and stirred for 1 hour to obtain a monomer diol composition M-1. The theoretical value e of the amount of hydroxyl groups per unit mass of this monomer diol composition M-1 is calculated as follows, since the molecular weight of butanediol is 90.12 and the number of hydroxyl groups per molecule is "2". Theoretical value of the amount of hydroxyl groups per unit mass e (mol / g) =(102.3 / 90.12)×2 / 102.3​ A portion of the obtained monomer diol composition M-1 was extracted, and 11.2 mg (= mass f) was placed in an NMR tube. In addition, 10.5 mg (= mass g) of triphenylmethane (molecular weight: 244.33) was placed in the NMR tube as an internal standard substance, followed by the addition of a deuterated chloroform solution to obtain an NMR measurement solution. The obtained NMR measurement solution was subjected to NMR measurement, and the integral ratio h (= integral value of OH of 1,4-butanediol / Ph3C- of triphenylmethane) was calculated. H )5.712 was obtained. Here, the measured value a of the amount of hydroxyl groups is calculated as follows. Measured amount of hydroxyl groups a = (integral value ratio h × mass g) / 244.33 =(5.712×10.5×10 -3 ) / 244.33 =2.455×10 -4 On the other hand, the theoretical value b of the amount of hydroxyl groups is calculated as follows: Theoretical value of the amount of hydroxyl groups b = Theoretical value of the amount of hydroxyl groups per unit mass e × mass f =(102.3 / 90.12)×2 / 102.3×(11.2×10 -3 ) =2.486×10 -4 Therefore, the a / b value is calculated as follows: a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b =2.455×10 -4 / 2.486×10 -4 =0.988

[0097] <Conversion rate of dimethyl terephthalate> A 0.354% by mass tetrabutoxy titanate solution was prepared using the monomer diol composition M-1 and tetrabutoxy titanate. 13.2 g of dimethyl terephthalate reagent and 6.0 g of the monomer diol composition M-1 were placed in a side-arm test tube equipped with a stirrer and purged with nitrogen. The tube was then immersed in a 150°C oil bath to melt and obtain a homogeneous solution. 1 g of a 0.354% by mass tetrabutoxy titanate solution was added and reacted for 30 minutes from the time of addition to obtain a reaction solution. A portion of the resulting reaction solution was sampled and analyzed by high-performance liquid chromatography. The residual rate of dimethyl terephthalate was 91.2%, and the conversion rate of dimethyl terephthalate (referred to as "DMT" in Table 1 and Tables 2 to 4 below) was estimated to be 8.8%.

[0098] <Transesterification reaction> 132 g of dimethyl terephthalate as a reagent and 75 g of the monomer diol composition M-1 were supplied to a glass reactor equipped with a stirrer and a distillation tube. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the inside of the reactor with nitrogen. The reactor was then immersed in an oil bath at 150°C. After confirming that the contents had dissolved, the rotation speed was increased to 150 rpm. Next, a tetrabutyl titanate solution containing 94% by mass of the monomer diol composition M-1 and 6% by mass of tetrabutyl titanate was added so that the titanium atom content was 33 ppm by mass relative to the polybutylene terephthalate obtained.The oil bath temperature was then raised from 150°C to 210°C over 105 minutes to obtain a transesterification reaction solution.

[0099] <Polycondensation reaction> A magnesium acetate solution containing 90% by mass of the monomer diol composition M-1 and 10% by mass of magnesium acetate tetrahydrate was added to the resulting transesterification reaction liquid so that the magnesium atom content was 48 ppm by mass relative to the polybutylene terephthalate obtained. An antioxidant solution containing 94% by mass of the monomer diol composition M-1 and 6% by mass of ADK STAB AO-60 was added to the resulting polybutylene terephthalate so that the ADK STAB AO-60 content was 530 ppm by mass relative to the polybutylene terephthalate obtained. Furthermore, a tetrabutyl titanate solution containing 94% by mass of the monomer diol composition M-1 and 6% by mass of tetrabutyl titanate was added to the resulting polybutylene terephthalate so that the titanium atom content was 61 ppm by mass relative to the polybutylene terephthalate obtained. The oil bath was heated from 210°C to 240°C over 45 minutes, and the internal pressure of the glass reactor was reduced from 760 Torr to 1 Torr over 85 minutes to carry out the polycondensation reaction. The internal pressure was then fully evacuated, and the polymerization reaction was terminated when the reactor's agitator reached a predetermined stirring power. The time when the oil bath was heated from 210°C was set to zero, and the polycondensation time until the predetermined stirring power was reached was 165 minutes. The reactor was then returned to a pressure of 760 Torr with nitrogen, and then the gauge pressure was increased to 1500 Torr, and polybutylene terephthalate was extracted in a strand form from the bottom of the reactor, and the strand-like polybutylene terephthalate was then pelletized using a rotary cutter to obtain pellet-like polybutylene terephthalate. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.984 dL / g, and the color b value was 1.4, earning an S rating.

[0100] [Example 2] A monomer diol composition M-2 was obtained in the same manner as in Example 1, except that 103.1 g of the main fraction C obtained in Production Example 1 was used as the monomer diol. ​NMR measurement was carried out in the same manner as in Example 1, except that 10.2 mg of a portion of the obtained monomer diol composition M-2 and 9.8 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.612. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.612 × 9.8 × 10 -3 / 244.33 =2.251×10 -4 Theoretical value of hydroxyl group amount b =(103.1 / 90.12)×2 / 103.1×(10.2×10 -3 ) =2.264×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.251 × 10 -4 / 2.264×10 -4 =0.994

[0101] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1 except that the monomer diol composition M-2 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 89.1% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 10.9%.

[0102] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-2 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 170 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.988 dL / g, and the color tone was evaluated as b value of 1.2, with the b value being graded as S.

[0103] [Comparative Example 1] A monomer diol composition M-3 was obtained in the same manner as in Example 1, except that 102.3 g of the main fraction A obtained in Production Example 1 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.6 mg of a portion of the obtained monomer diol composition M-3 and 10.3 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.815. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.815 × 10.3 × 10 -3 / 244.33 =2.451×10 -4 Theoretical value of hydroxyl group amount b =(102.3 / 90.12)×2 / 102.3×(11.6×10 -3 ) =2.574×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.451 × 10 -4 / 2.574×10 -4 =0.952

[0104] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-3 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 95.4% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 4.6%.

[0105] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-3 was used instead of the monomer diol composition M-1. ​In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 234 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.978 dL / g, and a color tone with a b value of 3.4, with the b value being evaluated as C.

[0106] Comparative Example 2 A monomer diol composition M-4 was obtained in the same manner as in Example 1, except that 99.8 g of the main fraction D obtained in Production Example 1 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.1 mg of a portion of the obtained monomer diol composition M-4 and 11.3 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.614. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.614 × 11.3 × 10 -3 / 244.33 =2.596×10 -4 Theoretical value of hydroxyl group amount b =(99.8 / 90.12)×2 / 99.8×(11.1×10 -3 ) =2.463×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.596 × 10 -4 / 2.463×10 -4 =1.054

[0107] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-4 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 94.2% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 5.8%.

[0108] ​<Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-4 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 223 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.998 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 5.2.

[0109] Table 1 shows the a / b values, DMT conversion rates, polycondensation times, and PBT color tone evaluations for Examples 1 and 2 and Comparative Examples 1 and 2. From Table 1, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PBT color tone evaluation is good.

[0110] [Table 1]

[0111] [Chemical Recycling BDO and Reagent Dimethyl Terephthalate] [Example 3] A monomer diol composition M-5 was obtained in the same manner as in Example 1, except that 105.3 g of the main fraction B obtained in Production Example 2 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.7 mg of a portion of the obtained monomer diol composition M-5 and 11.2 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.612. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.612 × 11.2 × 10 -3 / 244.33 =2.573×10 -4 Theoretical value of hydroxyl group amount b ​=(105.3 / 90.12)×2 / 105.3×(11.7×10 -3 ) =2.597×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.573 x 10 -4 / 2.597×10 -4 =0.991

[0112] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-5 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 90.1% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 9.9%.

[0113] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-5 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 180 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.982 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.5.

[0114] [Example 4] A monomer diol composition M-6 was obtained in the same manner as in Example 1, except that 102.6 g of the main fraction C obtained in Production Example 2 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.5 mg of a portion of the obtained monomer diol composition M-6 and 11.6 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.324. ​Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.324 × 11.6 × 10 -3 / 244.33 =2.528×10 -4 Theoretical value of hydroxyl group amount b =(102.6 / 90.12)×2 / 102.6×(11.5×10 -3 ) =2.552×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.528 x 10 -4 / 2.552×10 -4 =0.991

[0115] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 90.7% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 9.3%.

[0116] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 184 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.987 dL / g, and the color tone thereof was evaluated as S in terms of b value, with a b value of 1.8.

[0117] Comparative Example 3 ​A monomer diol composition M-7 was obtained in the same manner as in Example 1, except that 103.4 g of the main fraction A obtained in Production Example 2 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.4 mg of a portion of the obtained monomer diol composition M-7 and 11.4 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.214. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.214 × 11.4 × 10 -3 / 244.33 =2.433×10 -4 Theoretical value of hydroxyl group amount b =(103.4 / 90.12)×2 / 103.4×(11.4×10 -3 ) =2.530×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.433 × 10 -4 / 2.530×10 -4 =0.962

[0118] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-7 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 94.5% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 5.5%.

[0119] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-7 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 240 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.988 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 6.3.

[0120] Comparative Example 4 A monomer diol composition M-8 was obtained in the same manner as in Example 1, except that 101.1 g of the main fraction D obtained in Production Example 2 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 1, except that 11.5 mg of a portion of the obtained monomer diol composition M-8 and 11.2 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 5.814. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 5.814 × 11.2 × 10 -3 / 244.33 =2.665×10 -4 Theoretical value of hydroxyl group amount b =(101.1 / 90.12)×2 / 101.1×(11.5×10 -3 ) =2.552×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.665 × 10 -4 / 2.552×10 -4 =1.044

[0121] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 1, except that the monomer diol composition M-8 was used instead of the monomer diol composition M-1. As a result, the residual rate of dimethyl terephthalate was found to be 95.5% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 4.5%.

[0122] <Transesterification reaction / polycondensation reaction> ​Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 1, except that the monomer diol composition M-8 was used instead of the monomer diol composition M-1. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 252 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.994 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 7.2.

[0123] Table 2 shows the a / b values, DMT conversion rates, polycondensation times, and PBT color tone evaluations for Examples 3 and 4 and Comparative Examples 3 and 4. From Table 2, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PBT color tone evaluation is good.

[0124] [Table 2]

[0125] [Chemical recycling of ethylene glycol and the reagent dimethyl terephthalate] [Example 5] 135.3 g (mass c) of the main fraction B obtained in Production Example 3 as a monomer diol was placed in a recovery flask equipped with a stirrer. The recovery flask was then immersed in an oil bath heated to 150°C and stirred for 1 hour to obtain a monomer diol composition M-9. The theoretical value e of the amount of hydroxyl groups per unit mass of this monomer diol composition M-9 is calculated as follows, since the molecular weight of ethylene glycol is 62.07 and the number of hydroxyl groups per molecule is "2". Theoretical value of the amount of hydroxyl groups per unit mass e (mol / g) =(135.3 / 62.07)×2 / 135.3 ​A portion of the resulting monomer diol composition M-9 was extracted, and 11.2 mg (= mass f) was placed in an NMR tube. In addition, 10.2 mg (= mass g) of triphenylmethane (molecular weight: 244.33) was placed in the NMR tube as an internal standard, and then a deuterated chloroform solution was added to obtain an NMR measurement solution. The obtained NMR measurement solution was subjected to NMR measurement, and the integral value ratio h (integral value of OH of ethylene glycol / triphenylmethane Ph3C- H The integral value of (x) was obtained as 8.570. Here, the measured value a of the amount of hydroxyl groups is calculated as follows. Measured amount of hydroxyl groups a = (integral value ratio h × mass g) / 244.33 =(8.570×10.2×10 -3 ) / 244.33 =3.578×10 -4 On the other hand, the theoretical value b of the amount of hydroxyl groups is calculated as follows: Theoretical value of the amount of hydroxyl groups b = Theoretical value of the amount of hydroxyl groups per unit mass e × mass f =(135.3 / 62.07)×2 / 135.3×(11.2×10 -3 ) =3.609×10 -4 Therefore, the a / b value is calculated as follows: a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b =3.578×10 -4 / 3.609×10 -4 =0.991

[0126] <Conversion rate of dimethyl terephthalate> A 0.354% by mass tetrabutoxy titanate solution was prepared using the monomer diol composition M-9 and tetrabutoxy titanate. 13.2 g of dimethyl terephthalate reagent and 6.0 g of the monomer diol composition M-9 were placed in a side-arm test tube equipped with a stirrer and purged with nitrogen. The tube was then immersed in a 150°C oil bath to melt and obtain a homogeneous solution. 1 g of a 0.354% by mass tetrabutoxy titanate solution was added and reacted for 30 minutes from the time of addition to obtain a reaction solution. A portion of the resulting reaction solution was extracted, and high-performance liquid chromatography determined that the residual rate of dimethyl terephthalate was 85.1%, and the conversion rate of dimethyl terephthalate (DMT) was estimated to be 14.9%.

[0127] <Transesterification reaction> 151.6 g of dimethyl terephthalate as a reagent and 115.3 g of the monomer diol composition M-9 were supplied to a glass reactor equipped with a stirrer and a distillation tube. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the inside of the reactor with nitrogen. The reactor was then immersed in an oil bath at 150°C. After confirming that the contents had dissolved, the rotation speed was increased to 150 rpm. Subsequently, a magnesium acetate solution containing 93.5% by mass of the monomer diol composition M-9 and 6.5% by mass of magnesium acetate tetrahydrate was supplied so that the magnesium atom content was 100 ppm by mass relative to the polyethylene terephthalate obtained. Thereafter, the temperature of the oil bath was raised from 150°C to 225°C over 180 minutes to obtain a transesterification reaction solution.

[0128] <Polycondensation reaction> An ethyl phosphate solution containing 98.5% by mass of the monomer diol composition M-9 and 1.5% by mass of ethyl phosphate was added to the resulting transesterification reaction liquid so as to give a phosphorus atom concentration of 132 ppm by mass relative to the polyethylene terephthalate obtained. Also, an antimony trioxide solution containing 99% by mass of the monomer diol composition M-9 and 1% by mass of antimony trioxide was added to give an antimony atom concentration of 172 ppm by mass relative to the polyethylene terephthalate obtained. The oil bath was heated from 225°C to 280°C over 120 minutes, and the internal pressure of the glass reactor was reduced from 760 Torr to 1 Torr over 75 minutes to carry out the polycondensation reaction. The internal pressure was then fully evacuated, and the polymerization reaction was terminated when the reactor's agitator reached a predetermined stirring power. The time when the oil bath was heated from 225°C was set to zero, and the polycondensation time until the predetermined stirring power was reached was 189 minutes. The reactor was then returned to a pressure of 760 Torr with nitrogen, and then the gauge pressure was increased to 1500 Torr, and polyethylene terephthalate was extracted in the form of strands from the bottom of the reactor. The strands were then pelletized using a rotary cutter to obtain polyethylene terephthalate pellets. The resulting polyethylene terephthalate pellets had an intrinsic viscosity of 0.641 dL / g, and the color b value was 1.3, earning an S rating.

[0129] [Example 6] A monomer diol composition M-10 was obtained in the same manner as in Example 5, except that 132.6 g of the main fraction C obtained in Production Example 3 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 11.5 mg of a portion of the obtained monomer diol composition M-10 and 10.4 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 8.611. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. ​Measured amount of hydroxyl groups a = 8.611 × 10.4 × 10 -3 / 244.33 =3.665×10 -4 Theoretical value of hydroxyl group amount b =(132.6 / 62.07)×2 / 132.6×(11.5×10 -3 ) =3.705×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 3.665 x 10 -4 / 3.705×10 -4 =0.989

[0130] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-10 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 84.3% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 15.7%.

[0131] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-10 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 178 minutes. The resulting pelletized polyethylene terephthalate had an intrinsic viscosity of 0.644 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.4.

[0132] Comparative Example 5 A monomer diol composition M-11 was obtained in the same manner as in Example 5, except that 133.4 g of the main fraction A obtained in Production Example 3 was used as the monomer diol. ​NMR measurement was carried out in the same manner as in Example 5, except that 11.3 mg of a portion of the obtained monomer diol composition M-11 and 11.7 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 7.414. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 7.414 × 11.7 × 10 -3 / 244.33 =3.550×10 -4 Theoretical value of hydroxyl group amount b =(133.4 / 62.07)×2 / 133.4×(11.3×10 -3 ) =3.641×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 3.550 x 10 -4 / 3.641×10 -4 =0.975

[0133] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-11 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 97.8% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 2.2%.

[0134] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-11 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 230 minutes. The resulting polyethylene terephthalate pellets had an intrinsic viscosity of 0.634 L / g and a color tone with a b value of 5.6, which was evaluated as C.

[0135] Comparative Example 6 A monomer diol composition M-12 was obtained in the same manner as in Example 5, except that 131.1 g of the main fraction D obtained in Production Example 3 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 11.1 mg of a portion of the obtained monomer diol composition M-12 and 11.8 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 8.114. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 8.114 × 11.8 × 10 -3 / 244.33 =3.919×10 -4 Theoretical value of hydroxyl group amount b =(131.1 / 62.07)×2 / 131.1×(11.1×10 -3 ) =3.577×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 3.919 × 10 -4 / 3.577×10 -4 =1.096

[0136] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-12 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 98.6% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 1.4%.

[0137] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-12 was used instead of the monomer diol composition M-9. ​In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 255 minutes. The resulting pelletized polyethylene terephthalate had an intrinsic viscosity of 0.631 dL / g, and a color tone with a b value of 7.6, with the b value being evaluated as C.

[0138] Table 3 shows the a / b values, DMT conversion rates, polycondensation times, and PET color tone evaluations for Examples 5 and 6 and Comparative Examples 5 and 6. From Table 3, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PET color tone evaluation is good.

[0139] [Table 3]

[0140] [Biomass resource ethylene glycol and reagent dimethyl terephthalate] [Example 7] A monomer diol composition M-13 was obtained in the same manner as in Example 5, except that 131.2 g of the main fraction B obtained in Production Example 4 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 10.3 mg of a portion of the obtained monomer diol composition M-13 and 10.8 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 7.459. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 7.459 × 10.8 × 10 -3 / 244.33 =3.297×10 -4 Theoretical value of hydroxyl group amount b =(131.2 / 62.07)×2 / 131.2×(10.3×10 -3 ) =3.319×10 -4 Therefore, the a / b value is calculated as follows: ​a / b value = 3.297 × 10 -4 / 3.319×10 -4 =0.993

[0141] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-13 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 86.1% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 13.9%.

[0142] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-13 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 185 minutes. The resulting pelletized polyethylene terephthalate had an intrinsic viscosity of 0.631 dL / g, and the color tone had a b value of 1.5, with the b value being evaluated as S.

[0143] [Example 8] A monomer diol composition M-14 was obtained in the same manner as in Example 5, except that 132.1 g of the main fraction C obtained in Production Example 4 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 10.4 mg of a portion of the obtained monomer diol composition M-14 and 10.6 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 7.630. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 7.630 × 10.6 × 10 -3 / 244.33 =3.310×10 -4 Theoretical value of hydroxyl group amount b​ =(132.1 / 62.07)×2 / 132.1×(10.4×10 -3 ) =3.351×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 3.310 x 10 -4 / 3.351×10 -4 =0.988

[0144] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-14 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 85.6% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 14.4%.

[0145] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-14 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 176 minutes. The resulting pelletized polyethylene terephthalate had an intrinsic viscosity of 0.634 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.6.

[0146] Comparative Example 7 A monomer diol composition M-15 was obtained in the same manner as in Example 5, except that 132.3 g of the main fraction A obtained in Production Example 4 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 10.2 mg of a portion of the obtained monomer diol composition M-15 and 10.2 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 7.102. ​Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 7.102 × 10.2 × 10 -3 / 244.33 =2.965×10 -4 Theoretical value of hydroxyl group amount b =(132.3 / 62.07)×2 / 132.3×(10.2×10 -3 ) =3.287×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 2.965 × 10 -4 / 3.287×10 -4 =0.902

[0147] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-15 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 97.5% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 2.5%.

[0148] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-15 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 223 minutes. The resulting polyethylene terephthalate pellets had an intrinsic viscosity of 0.644 dL / g, and a color tone with a b value of 4.4, which was evaluated as C.

[0149] [Comparative Example 8] ​A monomer diol composition M-16 was obtained in the same manner as in Example 1, except that 131.1 g of the main fraction D obtained in Production Example 4 was used as the monomer diol. NMR measurement was carried out in the same manner as in Example 5, except that 11.1 mg of a portion of the obtained monomer diol composition M-16 and 11.2 mg of triphenylmethane as an internal standard were used, resulting in an integral value ratio h of 8.444. Here, the measured value a of the amount of hydroxyl groups and the theoretical value b of the amount of hydroxyl groups are calculated as follows. Measured amount of hydroxyl groups a = 8.444 × 11.2 × 10 -3 / 244.33 =3.871×10 -4 Theoretical value of hydroxyl group amount b =(131.1 / 62.07)×2 / 131.1×(11.1×10 -3 ) =3.577×10 -4 Therefore, the a / b value is calculated as follows: a / b value = 3.871 × 10 -4 / 3.577×10 -4 =1.082

[0150] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 5, except that the monomer diol composition M-16 was used instead of the monomer diol composition M-9. As a result, the residual rate of dimethyl terephthalate was found to be 98.3% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 1.7%.

[0151] <Transesterification reaction / polycondensation reaction> Polyethylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 5, except that the monomer diol composition M-16 was used instead of the monomer diol composition M-9. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 213 minutes. The resulting polyethylene terephthalate pellets had an intrinsic viscosity of 0.628 dL / g, and a color tone with a b value of 4.6, with the b value being evaluated as C.

[0152] Table 4 shows the a / b values, DMT conversion rates, polycondensation times, and PET color evaluations for Examples 7 and 8 and Comparative Examples 7 and 8. From Table 4, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PET color tone evaluation is good.

[0153] [Table 4]

[0154] [Biomass resource BDO and chemically recycled dimethyl terephthalate] [Example 9] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. The same procedure as in Example 2 was carried out, except that chemically recycled dimethyl terephthalate A obtained in Production Example 5 was used instead of dimethyl terephthalate as a reagent. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 88.1%, and the conversion rate of dimethyl terephthalate was estimated to be 11.9%.

[0155] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 2, except that chemically recycled dimethyl terephthalate A obtained in Production Example 5 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.996 dL / g, and the color tone was evaluated as b value of 1.2, with the b value being graded as S.

[0156] [Example 10] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. The same procedure as in Example 2 was carried out, except that chemically recycled dimethyl terephthalate B obtained in Production Example 6 was used instead of dimethyl terephthalate as a reagent. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 91.2%, and the conversion rate of dimethyl terephthalate was estimated to be 8.8%.

[0157] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 2, except that chemically recycled dimethyl terephthalate B obtained in Production Example 6 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.991 dL / g, and the color tone was evaluated as S with a b value of 0.8.

[0158] [Example 11] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. The same procedure as in Example 2 was carried out, except that chemically recycled dimethyl terephthalate C obtained in Production Example 7 was used instead of the reagent dimethyl terephthalate. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 92.5%, and the conversion rate of dimethyl terephthalate was estimated to be 7.5%.

[0159] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 2, except that chemically recycled dimethyl terephthalate C obtained in Production Example 7 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 168 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.999 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 0.9.

[0160] Table 5 shows the a / b value, DMT conversion rate, polycondensation time, and PBT color tone evaluation in Examples 9 to 11. Table 5 shows that even when chemically recycled dimethyl terephthalate is used, when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PBT color tone evaluation is good.

[0161] [Table 5]

[0162] [Biomass resource BDO and chemically recycled terephthalic acid] [Example 12] <Esterification reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. A glass reactor equipped with a stirrer and a distillation tube was charged with 113 parts by mass of the chemically recycled terephthalic acid A obtained in Production Example 8 and 184 parts by mass of the monomer diol composition M-2. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the atmosphere inside the reactor with nitrogen. The reactor was then immersed in an oil bath at 150°C. After confirming dissolution of the contents, the rotation speed was increased to 150 rpm. Next, a butanediol mixture containing 94% by mass of the monomer diol composition M-2 and 6% by mass of tetrabutyl titanate was charged so that the titanium atom concentration relative to the resulting polybutylene terephthalate was 40 ppm by mass. The temperature of the oil bath was then raised from 150°C to 210°C over 90 minutes and maintained at 210°C for 60 minutes, yielding an esterification reaction solution. 61 parts by mass of a distillate was obtained in the receiver at the end of the distillation tube.

[0163] <Polycondensation reaction> A butanediol mixture containing 90% by mass of the monomer diol composition M-2 and 10% by mass of magnesium acetate tetrahydrate was added to the resulting esterification reaction solution so that the magnesium atom content was 12 ppm by mass relative to the resulting polybutylene terephthalate. The oil bath was heated from 210°C to 240°C over 45 minutes, and the internal pressure of the glass reactor was reduced from 760 Torr to 0.5 Torr over 90 minutes to carry out a polycondensation reaction. The internal pressure was then fully evacuated, and the polycondensation reaction was terminated when the reactor's agitator reached a predetermined stirring power. Next, the reactor was restored to 760 Torr with nitrogen, and then the gauge pressure was increased to 1500 Torr, and polybutylene terephthalate was extracted in the form of strands from the bottom of the reactor to obtain strand-shaped polybutylene terephthalate.The strands were then pelletized using a rotary cutter to obtain pellet-shaped polybutylene terephthalate.In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 171 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.998 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.2.

[0164] [Example 13] <Esterification reaction / polycondensation reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. Polybutylene terephthalate was produced by carrying out an esterification reaction and a polycondensation reaction in the same manner as in Example 12, except that the chemically recycled terephthalic acid B obtained in Production Example 9 was used instead of the chemically recycled terephthalic acid A. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 174 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.996 dL / g, and the color tone thereof was evaluated as S in terms of b value, with a b value of 1.4.

[0165] [Example 14] <Esterification reaction / polycondensation reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. Polybutylene terephthalate was produced by carrying out an esterification reaction and a polycondensation reaction in the same manner as in Example 12, except that the chemically recycled terephthalic acid C obtained in Production Example 10 was used instead of the chemically recycled terephthalic acid A. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 176 minutes. The intrinsic viscosity of the resulting pelletized polybutylene terephthalate was 0.995 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.7.

[0166] [Example 15] <Esterification reaction / polycondensation reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. Polybutylene terephthalate was produced by carrying out an esterification reaction and a polycondensation reaction in the same manner as in Example 12, except that the chemically recycled terephthalic acid D obtained in Production Example 11 was used instead of the chemically recycled terephthalic acid A. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone thereof was evaluated as S in terms of b value, with a b value of 1.8.

[0167] [Example 16] <Esterification reaction / polycondensation reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. Polybutylene terephthalate was produced by carrying out an esterification reaction and a polycondensation reaction in the same manner as in Example 12, except that the chemically recycled terephthalic acid E obtained in Production Example 12 was used instead of the chemically recycled terephthalic acid A. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.994 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 2.0.

[0168] Table 6 shows the a / b values, polycondensation times, and PBT color tone evaluations for Examples 12 to 16. Table 6 shows that even when chemically recycled terephthalic acid is used, when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0169] [Table 6]

[0170] [Biomass resource BDO and chemically recycled bis(2-hydroxyethyl) terephthalate] [Example 17] <Transesterification reaction> In the same manner as in Example 2, a monomer diol composition M-2 was obtained. 100 parts by mass of the chemically recycled bis(2-hydroxyethyl) terephthalate obtained in Production Example 13 and 180 parts by mass of the monomer diol composition M-2 were fed into a glass reactor equipped with a stirrer and a distillation tube. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the inside of the reactor with nitrogen. The reactor was then immersed in an oil bath at 150°C. After confirming that the contents had dissolved, the rotation speed was increased to 150 rpm. Next, a butanediol mixture containing the monomer diol composition M-2 and 6% by mass of tetrabutyl titanate was added so that the titanium atom content was 33 ppm by mass relative to the resulting polybutylene terephthalate. The pressure was then reduced to 30 kPa, and the oil bath temperature was increased from 150°C to 220°C over 120 minutes. The pressure was then reduced from 30 kPa to 3 kPa, and the reaction was continued until the distillation ceased. The pressure was then restored to 101 kPa, yielding a transesterification reaction solution.

[0171] <Polycondensation reaction> A butanediol mixture containing the monomer diol composition M-2, 10% by mass of magnesium acetate tetrahydrate, and 20% by mass of water was added to the resulting transesterification reaction liquid so that the magnesium atom content was 48 ppm by mass relative to the polybutylene terephthalate obtained. A butanediol mixture containing 94% by mass of the monomer diol composition M-2 and 6% by mass of AO-60 was added so that the AO-60 content was 530 ppm by mass relative to the polybutylene terephthalate obtained. A butanediol mixture containing 94% by mass of the monomer diol composition M-2 and 6% by mass of tetrabutyl titanate was added so that the titanium atom content was 61 ppm by mass relative to the polybutylene terephthalate obtained. The oil bath was heated from 220°C to 240°C over 45 minutes, and the internal pressure of the glass reaction tank was reduced from 101 kPa to 133 Pa over 85 minutes to carry out a polycondensation reaction. The internal pressure was then fully evacuated, and the polycondensation reaction was terminated when the agitator in the reaction tank reached a predetermined stirring power. The reactor was then restored to 101 kPa with nitrogen, and the pressure was then increased to a predetermined level, and polybutylene terephthalate was extracted in the form of strands from the bottom of the reactor, and the strands were then pelletized using a rotary cutter to obtain polybutylene terephthalate pellets.

[0172] In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.7. Even when chemically recycled bis(2-hydroxyethyl) terephthalate is used, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0173] [Chemical Recycled BDO and Chemical Recycled Dimethyl Terephthalate] [Example 18] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. The same procedure as in Example 4 was carried out, except that chemically recycled dimethyl terephthalate A obtained in Production Example 5 was used instead of the reagent dimethyl terephthalate. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 89.6%, and the conversion rate of dimethyl terephthalate was estimated to be 10.4%.

[0174] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 4, except that chemically recycled dimethyl terephthalate A obtained in Production Example 5 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.995 dL / g, and the color tone was evaluated as S with a b value of 0.8.

[0175] [Example 19] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. The same procedure as in Example 4 was carried out, except that chemically recycled dimethyl terephthalate B obtained in Production Example 6 was used instead of the reagent dimethyl terephthalate. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 92.3%, and the conversion rate of dimethyl terephthalate was estimated to be 9.7%.

[0176] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 4, except that chemically recycled dimethyl terephthalate B obtained in Production Example 6 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.991 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 0.7.

[0177] [Example 20] <Conversion rate of dimethyl terephthalate> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. The same procedure as in Example 4 was carried out, except that chemically recycled dimethyl terephthalate C obtained in Production Example 7 was used instead of the reagent dimethyl terephthalate. When the conversion rate of dimethyl terephthalate was measured by high performance liquid chromatography, the residual rate of dimethyl terephthalate was 90.2%, and the conversion rate of dimethyl terephthalate was estimated to be 9.8%.

[0178] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out a transesterification reaction and a polycondensation reaction in the same manner as in Example 4, except that chemically recycled dimethyl terephthalate C obtained in Production Example 7 was used instead of the reagent dimethyl terephthalate. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.989 dL / g, and the color tone was evaluated as S with a b value of 0.5.

[0179] Table 7 shows the a / b values, DMT conversion rates, polycondensation times, and PBT color tone evaluations for Examples 18 to 20. Table 7 shows that even when using chemically recycled BDO and chemically recycled dimethyl terephthalate produced by depolymerization of polybutylene terephthalate, when the a / b value is 0.980 or more and less than 1.000, the DMT conversion rate is high, the polycondensation time is short, and the PBT color evaluation is good.

[0180] [Table 7]

[0181] [Chemical Recycled BDO and Chemical Recycled Terephthalic Acid] [Example 21] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 12, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 171 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.993 dL / g, and the color tone was evaluated as b value of 1.2, with the b value being graded as S.

[0182] [Example 22] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 13, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 170 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone thereof was evaluated as S in terms of b value, with a b value of 1.5.

[0183] [Example 23] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 14, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.991 dL / g, and the color tone thereof was evaluated as S in terms of b value, with a b value of 1.3.

[0184] [Example 24] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 15, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.4.

[0185] [Example 25] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 16, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 173 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.995 dL / g, and the color tone had a b value of 2.0, with the b value being evaluated as S.

[0186] The a / b values, polycondensation times, and PBT color tone evaluations for Examples 21 to 25 are summarized in Table 8. Table 8 shows that even when BDO produced by depolymerization of polybutylene terephthalate and chemically recycled terephthalic acid are used, when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0187] [Table 8]

[0188] [Chemical Recycled BDO and Chemical Recycled Bis(2-hydroxyethyl) Terephthalate] [Example 26] <Transesterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 17, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.998 dL / g, and the color tone was evaluated as b value of 1.5 and S. Even when BDO produced by depolymerization of polybutylene terephthalate and chemically recycled bis(2-hydroxyethyl) terephthalate are used, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0189] [Petroleum-derived BDO and chemically recycled bis(2-hydroxyethyl) terephthalate] [Example 27] 150.2 g (mass c) of the chemically recycled bis(2-hydroxyethyl) terephthalate obtained in Production Example 13 was placed in a recovery flask equipped with a stirrer. The recovery flask was then immersed in an oil bath heated to 150°C and stirred for 1 hour to obtain a monomer diol composition M-17. The theoretical value e of the amount of hydroxyl groups per unit mass of this monomer diol composition M-17 is calculated as follows, since the molecular weight of bis(2-hydroxyethyl) terephthalate is 254.24 and the number of hydroxyl groups per molecule is "2". Theoretical value of the amount of hydroxyl groups per unit mass e (mol / g) =(150.2 / 254.24)×2 / 150.2 ​A portion of the obtained monomer diol composition M-17 was extracted, and 10.5 mg (= mass f) was placed in an NMR tube. In addition, 10.7 mg (= mass g) of triphenylmethane (molecular weight: 244.33) was placed in the NMR tube as an internal standard substance, followed by the addition of a deuterated chloroform solution to obtain an NMR measurement solution. The obtained NMR measurement solution was subjected to NMR measurement, and the integral ratio h (= integral ratio of OH of bis(2-hydroxyethyl) terephthalate / Ph3C- of triphenylmethane) was calculated. H )1.882 was obtained. Here, the measured value a of the amount of hydroxyl groups is calculated as follows. Measured amount of hydroxyl groups a = (integral value ratio h × mass g) / 244.33 =(1.882×10.7×10 -3 ) / 244.33 =8.242×10 -5 On the other hand, the theoretical value b of the hydroxyl group is calculated as follows: Theoretical value of the amount of hydroxyl groups b = Theoretical value of the amount of hydroxyl groups per unit mass e × mass f =(150.2 / 254.24)×2 / 150.2×(10.5×10 -3 ) =8.260×10 -5 Therefore, the a / b value is calculated as follows: a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b =8.242×10 -5 / 8.260×10 -5 =0.998

[0190] <Transesterification reaction> 100 parts by mass of the monomer diol composition M-17 and 180 parts by mass of petroleum-derived 1,4-butanediol were fed into a glass reactor equipped with a stirrer and a distillation tube. The pressure in the glass reactor was reduced to approximately 100 Pa, and then the pressure was returned to atmospheric pressure with nitrogen. This operation was repeated three times to replace the atmosphere inside the reactor with nitrogen. The reactor was then immersed in an oil bath at 150°C. After confirming that the contents had dissolved, the rotation speed was increased to 150 rpm. Next, a butanediol mixture containing petroleum-derived 1,4-butanediol and 6% by mass of tetrabutyl titanate was fed so that the titanium atom content was 33 ppm by mass relative to the resulting polybutylene terephthalate. The pressure was then reduced to 30 kPa, and the temperature of the oil bath was increased from 150°C to 220°C over 120 minutes. Thereafter, the pressure was reduced from 30 kPa to 3 kPa, and the reaction was continued until the distillation ceased, and the pressure was then returned to 101 kPa to obtain an ester exchange reaction liquid.

[0191] <Polycondensation reaction> A butanediol mixture containing petroleum-derived 1,4-butanediol, 10% by mass of magnesium acetate tetrahydrate, and 20% by mass of water was supplied to the resulting transesterification reaction liquid so that the magnesium atom content was 48 ppm by mass relative to the resulting polybutylene terephthalate. A butanediol mixture containing 94% by mass of petroleum-derived 1,4-butanediol and 6% by mass of AO-60 was supplied to the resulting polybutylene terephthalate so that the AO-60 content was 530 ppm by mass relative to the resulting polybutylene terephthalate. A butanediol mixture containing 94% by mass of petroleum-derived 1,4-butanediol and 6% by mass of tetrabutyl titanate was supplied to the resulting polybutylene terephthalate so that the titanium atom content was 61 ppm by mass relative to the resulting polybutylene terephthalate. The oil bath was heated from 220°C to 240°C over 45 minutes, and the internal pressure of the glass reaction tank was reduced from 101 kPa to 133 Pa over 85 minutes to carry out a polycondensation reaction. The internal pressure was then fully evacuated, and the polycondensation reaction was terminated when the agitator in the reaction tank reached a predetermined stirring power. The reactor was then restored to 101 kPa with nitrogen, and the pressure was then increased to a predetermined level, and polybutylene terephthalate was extracted in the form of strands from the bottom of the reactor, and the strands were then pelletized using a rotary cutter to obtain polybutylene terephthalate pellets.

[0192] In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 171 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.987 dL / g, and the color tone was evaluated as b value of 1.9, with the b value being graded as S. Even when chemically recycled bis(2-hydroxyethyl) terephthalate is used, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0193] [Petroleum-derived BDO and chemically recycled dimethyl terephthalate] [Example 28] 103.2 g (mass c) of petroleum-derived 1,4-butanediol was placed in a recovery flask equipped with a stirrer, and the recovery flask was then immersed in an oil bath heated to 150°C and stirred for 1 hour to obtain a monomer diol composition M-18. The theoretical value e of the amount of hydroxyl groups per unit mass of this monomer diol composition M-18 is calculated as follows, since the molecular weight of butanediol is 90.12 and the number of hydroxyl groups per molecule is "2". Theoretical value of the amount of hydroxyl groups per unit mass e (mol / g) =(103.2 / 90.12)×2 / 103.2 A portion of the obtained monomer diol composition M-18 was extracted, and 10.5 mg (= mass f) was placed in an NMR tube. In addition, 10.2 mg (= mass g) of triphenylmethane (molecular weight: 244.33) was placed in the NMR tube as an internal standard substance, followed by adding a deuterated chloroform solution to obtain an NMR measurement solution. The obtained NMR measurement solution was subjected to NMR measurement, and the integral ratio h (= integral ratio of OH of bis(2-hydroxyethyl) terephthalate / Ph3C- of triphenylmethane) was calculated. H )5.545 was obtained. Here, the measured value a of the amount of hydroxyl groups is calculated as follows. Measured amount of hydroxyl groups a = (integral value ratio h × mass g) / 244.33 =(5.545×10.2×10 -3 ) / 244.33 =2.315×10 -4 On the other hand, the theoretical value b of the hydroxyl group is calculated as follows: Theoretical value of the amount of hydroxyl groups b = Theoretical value of the amount of hydroxyl groups per unit mass e × mass f =(103.2 / 90.12)×2 / 103.2×(10.5×10 -3 ) =2.330×10 -4 Therefore, the a / b value is calculated as follows: a / b value = measured amount of hydroxyl groups a / theoretical amount of hydroxyl groups b =2.315×10 -4 / 2.330×10 -4 =0.994

[0194] <Conversion rate of dimethyl terephthalate> The conversion rate of dimethyl terephthalate was measured in the same manner as in Example 9, except that the monomer diol composition M-18 was used instead of the monomer diol composition M-2. As a result, the residual rate of dimethyl terephthalate was found to be 90.2% by high performance liquid chromatography, and the conversion rate of dimethyl terephthalate was estimated to be 9.8%.

[0195] <Transesterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 9, except that the monomer diol composition M-18 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 174 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.991 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.2. Even when petroleum-derived 1,4-butanediol and chemically recycled dimethyl terephthalate are used, it can be seen that when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color tone evaluation is good.

[0196] [Biomass resource BDO and petroleum-derived terephthalic acid] [Example 29] <Esterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 12, except that PTA was used instead of the chemically recycled terephthalic acid A obtained in Production Example 8. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 175 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone had a b value of 0.3, with the b value being evaluated as S.

[0197] [Example 30] <Esterification reaction / polycondensation reaction> Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 29, except that QTA was used instead of PTA. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 172 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.992 dL / g, and the color tone was evaluated as b value of 1.2, with the b value being graded as S.

[0198] Comparative Example 9 In the same manner as in Comparative Example 1, a monomer diol composition M-3 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 29, except that the monomer diol composition M-3 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 201 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.990 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 3.2.

[0199] [Comparative Example 10] In the same manner as in Comparative Example 1, a monomer diol composition M-3 was obtained. Polybutylene terephthalate was produced by carrying out the transesterification reaction and polycondensation reaction in the same manner as in Example 30, except that the monomer diol composition M-3 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 205 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.994 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 3.3.

[0200] Table 9 shows the a / b values, polycondensation times, and PBT color tone evaluations for Examples 29 to 30 and Comparative Examples 9 to 10. Table 9 shows that even when BDO produced by the hydrogenation reaction of biosuccinic acid and petroleum-derived terephthalic acid are used, when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color evaluation is good.

[0201] [Table 9]

[0202] [Chemical Recycled BDO and Petroleum-Derived Terephthalic Acid] [Example 31] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 29, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 169 minutes. The resulting pelletized polybutylene terephthalate had an intrinsic viscosity of 0.996 dL / g, and the color tone was evaluated as S with a b value of 0.8.

[0203] [Example 32] <Esterification reaction / polycondensation reaction> In the same manner as in Example 4, a monomer diol composition M-6 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 30, except that the monomer diol composition M-6 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 171 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.998 dL / g, and the color tone was evaluated as S in terms of b value, with a b value of 1.6.

[0204] [Comparative Example 11] <Esterification reaction / polycondensation reaction> In the same manner as in Comparative Example 3, a monomer diol composition M-7 was obtained. Polybutylene terephthalate was produced by carrying out the esterification reaction and polycondensation reaction in the same manner as in Example 29, except that the monomer diol composition M-7 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 204 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.992 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 3.1.

[0205] [Comparative Example 12] <Esterification reaction / polycondensation reaction> In the same manner as in Comparative Example 3, a monomer diol composition M-7 was obtained. Polybutylene terephthalate was produced by carrying out transesterification and polycondensation reactions in the same manner as in Example 30, except that the monomer diol composition M-7 was used instead of the monomer diol composition M-2. In the polycondensation reaction, the polycondensation time until the predetermined stirring power was reached was 202 minutes. The intrinsic viscosity of the obtained pelletized polybutylene terephthalate was 0.992 dL / g, and the color tone was evaluated as C in terms of b value, with a b value of 3.4.

[0206] Table 10 shows the a / b values, polycondensation times, and PBT color tone evaluations for Examples 31 and 32 and Comparative Examples 11 and 12. Table 10 shows that even when BDO produced by depolymerization of polybutylene terephthalate and petroleum-derived terephthalic acid are used, when the a / b value is 0.980 or more and less than 1.000, the polycondensation time is short and the PBT color evaluation is good.

[0207] [Table 10]

Claims

1. A monomer diol composition, wherein the value (a / b) obtained by dividing the measured value (a) of the amount of hydroxyl groups measured by the following measurement method by the theoretical value (b) of the amount of hydroxyl groups is 0.980 or more and less than 1.

000. <Measurement method> Step 1: Weighing the monomer diol composition to obtain the mass of the monomer diol composition Step 2: A step of calculating the theoretical value b of the hydroxyl group content of the monomer diol composition obtained in Step 1 using the mass of the monomer diol composition obtained in Step 1. Step 3: A step of measuring the monomer diol composition obtained in Step 1 by NMR to obtain a measured value a of the hydroxyl group amount of the monomer diol composition. Step 4: A step of obtaining a value (a / b) by dividing the measured value a of the amount of hydroxyl groups obtained in Step 3 by the theoretical value b of the amount of hydroxyl groups obtained in Step 2.

2. The monomer diol composition according to claim 1 , wherein the monomer diol contained in the monomer diol composition is 85% by mass or more.

3. The monomer diol composition of claim 1 , wherein the monomer diol composition of step 1 is a heated monomer diol composition.

4. The monomer diol composition of claim 1 , wherein the monomer diol composition is a liquid.

5. The monomer diol composition of claim 1 , wherein the monomer diol composition is a solution.

6. The monomer diol composition of claim 1 wherein the monomer diol is an alkane diol.

7. The monomer diol composition according to claim 6 , wherein the alkanediol is produced using a biomass resource as a raw material.

8. 8. The monomer diol composition of claim 7, wherein the alkanediol is an alkanediol produced by fermentation.

9. 9. The monomer diol composition of claim 8, wherein the alkanediol is an alkanediol produced by direct fermentation of sugars.

10. 8. The monomer diol composition according to claim 7, wherein the alkanediol is produced by hydrogen reduction of succinic acid or a succinic acid derivative produced using a biomass resource.

11. 2. The monomer diol composition of claim 1, wherein the monomer diol is a monomer diol produced by depolymerization of a polyester.

12. 12. The monomer diol composition of claim 11, wherein the polyester is a polyalkylene terephthalate.

13. 13. The monomer diol composition of claim 12, wherein the monomer diol is butanediol, ethylene glycol, bis(2-hydroxyethyl) terephthalate, or bis(4-hydroxybutyl) terephthalate, and the polyalkylene terephthalate is polybutylene terephthalate or polyethylene terephthalate.

14. 2. The monomer diol composition of claim 1, wherein the monomer diol is butadiene, butyne-1,4-diol, butane, or butane diol prepared with propylene oxide.

15. A method for producing a polyester, using the monomer diol composition according to any one of claims 1 to 14.

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