Copolymerized polybutylene terephthalate composition and method for producing the same

Abstract

To provide a polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition having stable and excellent hinge characteristics and high lock strength.SOLUTION: A polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition having a polytetramethylene ether glycol copolymerization amount of 0.1 to 2.0% by mass, obtained by reacting a polytetramethylene ether glycol-copolymerized polybutylene terephthalate obtained by copolymerizing 7 to 32% by mass of polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 with dimethyl terephthalate or a reaction product of terephthalic acid and 1, 4-butanediol.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polytetramethylene ether glycol-co-polybutylene terephthalate (hereinafter sometimes abbreviated as "PBT") composition, which is polybutylene terephthalate copolymerized with polytetramethylene ether glycol (hereinafter sometimes abbreviated as "PTMG"). The present invention also relates to a method for producing a polytetramethylene ether glycol-co-polybutylene terephthalate (hereinafter sometimes abbreviated as "PTMG-co-PBT") composition, which can improve the accuracy of the copolymerization amount of the PTMG-co-PBT composition. [Background technology]

[0002] Polybutylene terephthalate (PBT) has excellent mechanical properties, heat resistance, moldability, and recyclability, as well as high mechanical strength and excellent chemical resistance, and is therefore widely used as a material for industrial molded products such as connectors, relays, and switches in automobiles and electrical and electronic devices. PBT is also widely used in films, sheets, fibers (filaments), and other applications, which has led to a demand for high-quality PBT with excellent productivity.

[0003] Among these, resins with better flowability are required for molding applications involving thin-walled hinge portions of electrical components and connectors. Furthermore, as the use of PBT electrical components and connectors increases, cracks and chips in the thin-walled portions and hinge structures of components and connectors during assembly, transportation, and installation into automobiles have become a major problem. Especially during work in low temperatures in winter or when components and connectors are subjected to large impacts, cracks and chips occur in the thin-walled portions and hinge structures of components and connectors, significantly reducing productivity.

[0004] For this reason, PBT copolymerized with polytetramethylene ether glycol (hereinafter referred to as "PTMG") is known as a resin that has excellent impact resistance, preventing cracks and chips from occurring in the thin-walled and hinged parts of such molded products, and that does not break even when used under low-temperature conditions, as well as excellent fluidity during molding.

[0005] Patent Document 1 describes a PBT composition containing 3 to 7 mass % PTMG obtained by compounding PTMG copolymer PBT and homo-PBT. However, in a PBT composition produced by simply compounding and mixing these, depending on the compounding conditions, the resin mixing is inferior to that of copolymer resins, resulting in variations in hinge characteristics. If the mixing is poor, the desired hinge characteristics may not be obtained, and improvements are desired. Furthermore, in consideration of the recent trend toward smaller, lighter, and thinner molded products, PBT compositions containing 3 to 7 mass % PTMG are soft and therefore have a low flexural modulus, which reduces the locking strength between connectors and can cause problems such as the locking portion becoming dislodged due to deformation.

[0006] For these reasons, there is a demand for PTMG copolymerized PBT that has stable and excellent hinge properties and high lock strength.

[0007] Patent Document 2 describes copolymerized PBT in which the copolymerization amount of PTMG is 3% by mass or more and 7% by mass or less, but this is outside the scope of the present invention. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 10-125438 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-288345 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to solve the above-mentioned problems of the prior art and to provide a PTMG copolymer PBT composition having excellent hinge properties and high lock strength, and a method for producing a PTMG copolymer PBT composition that can produce such a PTMG copolymer PBT with a small amount of PTMG copolymerization with high precision in the amount of PTMG copolymerization. [Means for solving the problem]

[0010] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have found that this problem can be solved by further polymerizing a PBT oligomer composed of dimethyl terephthalate or terephthalic acid and 1,4-butanediol, which are PBT raw materials, onto a PTMG-copolymerized PBT having a predetermined PTMG copolymerization amount, thereby reducing the PTMG copolymerization amount. The present invention was completed based on these findings, and the gist of the present invention is as follows.

[0011] [1] Polytetramethylene ether glycol copolymerized polybutylene terephthalate obtained by copolymerizing 7 to 32 mass% of polytetramethylene ether glycol having a number average molecular weight of 650 to 2000; a reaction product of dimethyl terephthalate or terephthalic acid with 1,4-butanediol; is reacted with A polytetramethylene ether glycol copolymerized polybutylene terephthalate composition, in which the amount of polytetramethylene ether glycol copolymerized is 0.1 to 2.0% by mass.

[0012] [2] The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to [1], wherein the amount of the polytetramethylene ether glycol copolymerized polybutylene terephthalate used is 1 to 20 mass% based on the total amount of the polytetramethylene ether glycol copolymerized polybutylene terephthalate and the reaction product of dimethyl terephthalate or terephthalic acid with 1,4-butanediol.

[0013] [3] The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to [1] or [2], wherein the dimethyl terephthalate is derived from petroleum, chemical recycling, or biomass.

[0014] [4] The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to any one of [1] to [3], wherein the terephthalic acid is derived from petroleum, chemical recycling, or biomass.

[0015] [5] The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to any one of [1] to [4], wherein the 1,4-butanediol is derived from petroleum, chemical recycling, or biomass.

[0016] [6] The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to any one of [1] to [5], wherein the polytetramethylene ether glycol is derived from petroleum, chemical recycling, or biomass.

[0017] [7] A method for producing a polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition, comprising producing the polytetramethylene ether glycol-copolymerized polybutylene terephthalate in a polycondensation reaction tank, extracting a portion of the produced polytetramethylene ether glycol-copolymerized polybutylene terephthalate from the polycondensation reaction tank, and using the polycondensation reaction tank in which the remainder of the polytetramethylene ether glycol-copolymerized polybutylene terephthalate remains to produce the polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition. [Effects of the Invention]

[0018] The PTMG copolymer PBT composition of the present invention has excellent hinge properties and high lock strength. Furthermore, the method for producing the PTMG copolymer PBT composition of the present invention allows for highly accurate control of the amount of PTMG copolymerized when producing a PTMG copolymer PBT with such a small amount of PTMG copolymerized, making these compositions of great industrial value. The PTMG copolymer PBT composition of the present invention can be used in a wide range of applications, including industrial molded products such as connectors, relays, and switches for automobiles and electrical and electronic devices, as well as films, sheets, and fibers (filaments). In particular, due to its excellent hinge properties and high locking strength, it is industrially useful as a molding material for thin-walled parts and hinge structure parts of electrical parts and connectors. [Brief explanation of the drawings]

[0019] [Figure 1] Figure 1(a) is a plan view of a hinged specimen for hinge property testing, Figure 1(b) is a side view of the same, Figure 1(c) is an enlarged side view of the hinge portion, and Figure 1(d) is a conceptual diagram showing the state of the hinge property test. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following describes in detail an embodiment of the present invention. However, the description of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to 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 mass" and "parts by weight" have the same meaning, and "% by mass" and "% by weight" have the same meaning. 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. Also, "ppm" indicates "ppm by mass."

[0021] [PTMG copolymerized PBT composition] The PTMG copolymerized PBT composition of the present invention is a PTMG copolymerized PBT composition having a PTMG copolymerization amount of 0.1 to 2.0 mass%, which is obtained by reacting a PTMG copolymerized PBT obtained by copolymerizing 7 to 32 mass% of PTMG having a number average molecular weight of 650 to 2000 with a reaction product of dimethyl terephthalate (hereinafter sometimes abbreviated as "DMT") or terephthalic acid (hereinafter sometimes abbreviated as "TPA") and 1,4-butanediol (hereinafter sometimes abbreviated as "BDO").

[0022] In the present invention, the "amount of PTMG copolymerized" does not necessarily mean only the PTMG copolymerized with PBT, but is determined by analyzing the PTMG-copolymerized PBT or the PTMG-copolymerized PBT composition by the method described in the Examples section below, and may also include some PTMG that is not copolymerized with PBT. From this viewpoint, in the present invention, the "PTMG copolymerized PBT composition" is referred to as the "PTMG copolymerized PBT composition" to distinguish it from the PTMG copolymerized PBT having a PTMG copolymerization amount of 7 to 32 mass% that is used as a raw material for producing one having a PTMG copolymerization amount of 0.1 to 2.0 mass%, but it is generally referred to as the "PTMG copolymerized PBT". Hereinafter, the PTMG copolymer PBT having a PTMG copolymerization amount of 7 to 32 mass%, which is used as a raw material for producing the PTMG copolymer PBT composition of the present invention having a PTMG copolymerization amount of 0.1 to 2.0 mass%, will be referred to as the "raw material PTMG copolymer PBT", and the PTMG copolymer PBT composition of the present invention obtained from this raw material PTMG copolymer PBT will be referred to as the "produced PTMG copolymer PBT" or "PTMG copolymer PBT of the present invention".

[0023] [Components of PTMG copolymer PBT] The diol component constituting the raw material PTMG copolymerized PBT and the produced PTMG copolymerized PBT is mainly composed of BDO and PTMG as a copolymerization component, and the dicarboxylic acid component is mainly composed of dimethyl terephthalate or terephthalic acid. That is, in the present invention, PTMG-copolymerized PBT refers to a polymer having a structure in which a dicarboxylic acid component containing terephthalic acid or dimethyl terephthalate is ester-bonded to a diol component containing BDO and PTMG, wherein 50 mol % or more of the dicarboxylic acid component is terephthalic acid or dimethyl terephthalate, and 50 mol % or more of the diol component is BDO. The proportion of terephthalic acid or dimethyl terephthalate in all dicarboxylic acid components is preferably 70 mol % or more, more preferably 80 mol % or more, and particularly preferably 90 mol % or more. The proportion of BDO in all diol components is preferably 70 mol % or more, more preferably 80 mol % or more, and even more preferably 90 mol % or more. If the proportion of terephthalic acid or dimethyl terephthalate or BDO is less than 50 mol %, the crystallization rate of the PTMG-copolymerized PBT decreases, resulting in poor moldability.

[0024] <Dimethyl terephthalate> The dimethyl terephthalate used in the present invention can be produced from terephthalic acid synthesized by oxidation of paraxylene, a petrochemical product (petrochemical-derived terephthalic acid), chemically recycled terephthalic acid obtained by recovering and depolymerizing waste polyester, or biomass-derived terephthalic acid obtained using paraxylene produced from isobutanol or ethanol produced from plant-derived raw materials such as corn or sugarcane. For example, a method has been proposed in which isobutanol is obtained from a renewable carbon source and terephthalic acid is obtained by oxidizing paraxylene through dehydration dimerization of isobutanol (for example, JP-A 2013-506717). From the terephthalic acid obtained by this method, dimethyl terephthalate can be obtained by a conventional method. From the perspective of aiming for a sustainable society for the global environment and future generations, the terephthalic acid that is the raw material for DMT used in the present invention is preferably terephthalic acid derived from chemical recycling. From the same viewpoint, the terephthalic acid that is the raw material for the DMT of the present invention is preferably biomass-derived terephthalic acid. These terephthalic acids are esterified with methanol under high temperature and pressure conditions, and the esterification reaction mixture is separated and purified to obtain DMT. In the present invention, DMT derived from each of these can be used, and two or more of these may be used in combination.

[0025] <Terephthalic acid> The terephthalic acid used in the present invention may be terephthalic acid synthesized by oxidation of paraxylene, a petrochemical product (petrochemical-derived terephthalic acid), terephthalic acid derived from chemical recycling obtained by recovering waste polyester and depolymerizing the recovered polyester, or biomass-derived terephthalic acid obtained using paraxylene produced from isobutanol or ethanol produced from plant-derived raw materials such as corn or sugarcane. From the viewpoint of aiming for a sustainable society for the global environment and future generations, the TPA used in the present invention is preferably terephthalic acid derived from chemical recycling. From the same viewpoint, the TPA used in the present invention is preferably a biomass-derived TPA. In the present invention, TPA derived from each of these can be used, and two or more of these may be used in combination.

[0026] <bdo> There are no particular limitations on the method for producing BDO used in the present invention. The BDO used in the present invention may be petrochemical-derived BDO, chemically recycled BDO, or biomass-derived BDO, or may be a mixture of these. BDO can be produced by commonly used methods such as the Reppe process, the allyl alcohol process, the butadiene process, and the hydrogenation of succinic acid. Furthermore, these intermediates or BDO itself can be produced by fermentation (direct fermentation). The BDO used in the present invention may be a mixture of two or more BDOs derived from these methods. From the perspective of aiming for a sustainable society for the sake of the global environment and future generations, the BDO used in the present invention is preferably BDO produced from biomass resources or BDO produced by recycling waste or defective products.

[0027] Preferred BDO produced using biomass resources as raw materials is an alkanediol produced by fermentation. Examples include BDO produced by direct fermentation of sugar, and biomass-derived BDO produced by hydrogenating succinic acid or succinic acid derivatives produced using biomass resources, such as 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). Furthermore, examples of chemically recycled BDO produced by depolymerizing waste polyester include chemically recycled BDO obtained by depolymerizing polybutylene terephthalate. In any of the BDO production methods, it is preferable to carry out distillation purification or hydrogenation purification in each step as necessary.

[0028] <ptmg> The PTMG copolymerized in the raw material PTMG copolymerized PBT has a number average molecular weight of 650 to 2,000. The number average molecular weight (Mn) of the PTMG used in the present invention is usually 650 or more, preferably 850 or more, more preferably 900 or more, while the upper limit is usually 2000 or less, preferably 1300 or less, more preferably 1100 or less.

[0029] PTMG with a number average molecular weight (Mn) in this range is easy to obtain, and when the number average molecular weight (Mn) of PTMG is within the above range, copolymerization thereof makes it possible to obtain a PTMG copolymerized PBT with excellent flexibility and elastic recovery.

[0030] The number average molecular weight (Mn) of PTMG is a value measured by gel permeation chromatography (GPC) according to a conventional method, but for commercially available products, the catalog value can be used.

[0031] PTMG is produced by carrying out a ring-opening polymerization reaction of tetrahydrofuran (hereinafter sometimes abbreviated as "THF") in the presence of a ring-opening polymerization catalyst. The THF used as a raw material for producing PTMG can be THF produced from BDO by the following production method. As mentioned above, methods for producing BDO include the commonly used Reppe process, allyl alcohol process, butadiene process, and succinic acid hydrogenation process. Furthermore, these intermediates or BDO itself can be produced by fermentation (direct fermentation process). The BDO used as a raw material for THF can be a mixture of two or more BDOs derived from these processes. From the perspective of aiming for a sustainable society for the global environment and future generations, it is preferable to use BDO obtained by direct fermentation or by hydrogenating succinic acid obtained by fermentation as the raw material for THF, and it is even more preferable to use BDO obtained by hydrogenating succinic acid obtained by fermentation. Chemically recycled BDO produced by chemical recycling through depolymerization of polyester using 1,4-butanediol as a raw material is also preferred. In any of the BDO production methods, it is preferable to carry out distillation purification or hydrogenation purification in each step as necessary. Such biomass-derived PTMG is commercially available from Mitsubishi Chemical Corporation under the name "BioPTMG."

[0032] <Raw material PTMG copolymerized PBT> The amount of PTMG copolymerized in the starting material PTMG copolymerized PBT used to produce the PTMG copolymerized PBT of the present invention is 7 to 32 mass %. If the amount of PTMG copolymerized in the starting PTMG-copolymerized PBT is less than 7% by mass, the amount of PTMG copolymerized tends to vary, which is undesirable.The lower limit of the amount of PTMG copolymerized in the starting PTMG-copolymerized PBT is preferably 8% by mass. If the PTMG copolymerization amount of the starting PTMG-copolymerized PBT exceeds 32% by mass, the starting PTMG-copolymerized PBT will have poor thermal stability and will be susceptible to decomposition and oxidative degradation while waiting in a polycondensation reaction tank during the production of the finished PTMG-copolymerized PBT, which is undesirable. The upper limit of the PTMG copolymerization amount of the starting PTMG-copolymerized PBT is preferably 30% by mass, more preferably 25% by mass, even more preferably 23% by mass, and most preferably 22% by mass or less.

[0033] <PTMG Copolymerized PBT of the Present Invention> The PTMG copolymerization amount of the PTMG copolymerized PBT of the present invention, i.e., the produced PTMG copolymerized PBT, is 0.1 to 2.0% by mass. If the PTMG copolymerization amount of the PTMG copolymerized PBT is within this range, a molded article with excellent impact resistance, excellent hinge characteristics, and high lock strength can be obtained. The PTMG copolymerization amount of the produced PTMG copolymerized PBT is preferably 0.2% by mass or more, more preferably 0.3% by mass or more. Similarly, it is preferably 1.9% by mass or less, more preferably 1.8% by mass or less.

[0034] The PTMG copolymerized PBT of the present invention is produced by reacting a raw material PTMG copolymerized PBT with a reaction product of a dicarboxylic acid component mainly composed of DMT or TPA and a diol component mainly composed of BDO, and at this time, these are used so that the ratio of the raw material PTMG copolymerized PBT to the total of the raw material PTMG copolymerized PBT and the reaction product of DMT or TPA and BDO is 1 to 20 mass%. Here, by setting the proportion of the raw material PTMG copolymerized PBT to 1 to 20 mass%, the PTMG copolymerized PBT of the present invention having a PTMG copolymerization amount of 0.1 to 2.0 mass% can be produced with high precision from the raw material PTMG copolymerized PBT having a PTMG copolymerization amount of 7 to 32 mass%. The lower limit of the proportion of the raw material PTMG copolymerized PBT is preferably 2% by mass, more preferably 3% by mass, even more preferably 4% by mass, and most preferably 5% by mass. Meanwhile, the upper limit is preferably 15% by mass, more preferably 13% by mass, even more preferably 10% by mass, and most preferably 8% by mass. If the proportion of the raw material PTMG copolymerized PBT is less than the lower limit, the hinge resistance effect tends to decrease. Meanwhile, if the proportion exceeds the upper limit, the product tends to be susceptible to decomposition and oxidative degradation while waiting in the reaction vessel.

[0035] [Method for producing PTMG copolymer PBT of the present invention] Although there are no particular limitations on the method for producing the PTMG copolymer PBT of the present invention by reacting a reaction product of DMT or TPA with BDO with a raw material PTMG copolymer PBT, it is preferable to produce the raw material PTMG copolymer PBT in a polycondensation reaction tank according to the method for producing the PTMG copolymer PBT of the present invention, then withdraw only a portion of the raw material PTMG copolymer PBT produced from the polycondensation reaction tank, and use the polycondensation reaction tank in which the remainder of the raw material PTMG copolymer PBT remains to produce the PTMG copolymer PBT of the present invention. More specifically, the reaction product of a dicarboxylic acid component mainly composed of DMT or TPA and a diol component mainly composed of BDO is added to the polycondensation reaction tank in which the raw material PTMG copolymer PBT remains, and further polycondensation is carried out to produce the PTMG copolymer PBT of the present invention. In this case, the dicarboxylic acid component mainly composed of DMT or TPA and the diol component mainly composed of BDO may be directly charged into the polycondensation reaction tank. However, specifically, it is preferable from the viewpoint of production that these components are subjected to an ester exchange reaction or an esterification reaction in a transesterification reaction tank or an esterification reaction tank upstream of the polycondensation reaction tank in order to form a low-molecular-weight homo-PBT oligomer, which is then charged into the polycondensation reaction tank.

[0036] The reason why a starting material PTMG copolymerized PBT having a relatively large amount of PTMG copolymerized is produced and then an oligomer of DMT or TPA and BDO is reacted with this starting material PTMG copolymerized PBT in a polycondensation reaction tank is as follows. That is, when an attempt is made to produce a PTMG copolymerized PBT having a PTMG copolymerization amount of 0.1 to 2.0 mass % by reacting DMT or TPA, BDO, and PTMG, the PTMG copolymerization amount of the resulting PTMG copolymerized PBT varies, making it difficult to produce a PTMG copolymerized PBT having the desired PTMG copolymerization amount. As described in Patent Document 1, simply mixing homo-PBT with a raw material PTMG-copolymerized PBT having a relatively large PTMG copolymerization amount will result in poor mixing, making it impossible to obtain a PTMG-copolymerized PBT with a low PTMG copolymerization amount and stable performance. In contrast, according to the present invention, a starting material PTMG copolymerized PBT having a relatively large PTMG copolymerization amount is produced in advance, and this starting material PTMG copolymerized PBT is then subjected to a polycondensation reaction with an oligomer of DMT or TPA and BDO. This makes it possible to reduce the PTMG copolymerization amount and to stably produce a PTMG copolymerized PBT having the desired PTMG copolymerization amount by precisely controlling the PTMG copolymerization amount. Moreover, in this case, by adding an oligomer of DMT or TPA and BDO to a polycondensation reaction tank containing the raw material PTMG copolymerized PBT and carrying out polycondensation, work efficiency can be improved and productivity can be increased.

[0037] A method for producing the starting PTMG copolymer PBT will be described below, followed by a method for producing the PTMG copolymer PBT of the present invention using this starting PTMG copolymer PBT.

[0038] [Manufacturing method for raw material PTMG copolymer PBT] <Raw material dicarboxylic acid component, diol component, copolymer component> As mentioned above, PTMG copolymerized PBT refers to a polymer having a structure in which a dicarboxylic acid component containing DMT or TPA is ester-bonded to a diol containing BDO and a PTMG component, in which 50 mol % or more of the dicarboxylic acid component is composed of terephthalic acid or dimethyl terephthalate, and 50 mol % or more of the diol component is composed of BDO.

[0039] In the present invention, the dicarboxylic acid component includes dicarboxylic acids and dicarboxylic acid derivatives. The dicarboxylic acid components other than terephthalic acid or dimethyl terephthalate used as raw materials for producing PTMG-copolymerized PBT are not particularly limited, and examples thereof 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, as well as derivatives of these dicarboxylic acids. Examples of dicarboxylic acid derivatives include esters of these dicarboxylic acids and ester-forming derivatives such as dicarboxylic acid halides. These dicarboxylic acid components other than terephthalic acid or dimethyl terephthalate may be used alone or in combination of two or more. Dicarboxylic acid components such as succinic acid may be derived from chemical recycling or biomass.

[0040] In the present invention, the diol component other than BDO and PTMG is not particularly limited, and examples thereof include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, and dibutylene glycol; alicyclic diols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, and 1,4-cyclohexanedimethylol; and aromatic diols such as xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone. As for these diol components other than BDO and PTMG, one kind may be used alone, or two or more kinds may be used in combination. Diol components other than BDO and PTMG may also be derived from biomass.

[0041] In the present invention, one or more of the following may further be used as copolymerization components: 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.

[0042] <Manufacturing method for raw material PTMG copolymer PBT> There are no particular limitations on the method for producing the starting material PTMG copolymerized PBT, and the production method may be continuous or batchwise. The raw material PTMG copolymerized PBT can be produced by a conventional method, for example, by mixing a dicarboxylic acid component mainly composed of TPA, a diol component other than PTMG mainly composed of BDO, and PTMG in a predetermined ratio while stirring to form a raw material slurry, heating this raw material slurry under normal pressure or reduced pressure to cause an esterification reaction to form a PTMG copolymerized PBT oligomer, and then gradually reducing the pressure of the resulting oligomer while heating it to cause a melt polycondensation reaction to obtain PTMG copolymerized PBT in a melt polycondensation step. When dimethyl terephthalate is used, it is heated together with BDO, melted, and then subjected to an ester exchange reaction to obtain an oligomer.

[0043] An example of the process for producing an oligomer is a method in which an esterification reaction tank or a transesterification reaction tank is used, and the esterification reaction or transesterification reaction (the proportion of all carboxyl groups or ester groups in the raw dicarboxylic acid component that have reacted with the diol component to be esterified or transesterified) is carried out using a catalyst under normal or reduced pressure to obtain an oligomer, while removing water or methanol produced in the reaction and excess diol component from the system. Typically, the temperature of the esterification reaction or transesterification reaction is about 210 to 230° C., the pressure is about 10 to 133 kPa, and the reaction time is about 1 to 4 hours.

[0044] An example of the melt polycondensation step is a method in which a polycondensation reaction vessel is used, and the diol produced is distilled out of the system while heating under reduced pressure in the presence of a catalyst.

[0045] 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.

[0046] The polycondensation reaction tank may be a single tank or a multi-stage tank, but in order to suppress coloration and deterioration and to inhibit an increase in terminal groups such as vinyl groups, it is preferable 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. The reaction rate can be increased by, for example, increasing the degree of vacuum, accelerating the rate of temperature rise, or increasing the rate of renewal of the reaction liquid surface.

[0047] The PTMG copolymerized PBT 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 into granular materials such as pellets or chips (for example, about 3 to 10 mm in length).

[0048] As will be described later, in producing the starting PTMG copolymerized PBT, only a portion of the PTMG copolymerized PBT produced in this polycondensation reaction tank is extracted, and the remainder is left behind in the polycondensation reaction tank.The PTMG copolymerized PBT remaining in the polycondensation reaction tank is used as the starting PTMG copolymerized PBT to produce the PTMG copolymerized PBT of the present invention as will be described later. In this case, the amount of PTMG copolymerized PBT to be left in the polycondensation reaction tank is appropriately determined depending on the PTMG copolymerization amount of the produced PTMG copolymerized PBT (raw material PTMG copolymerized PBT) and the PTMG copolymerization amount of the target produced PTMG copolymerized PBT.

[0049] <Polycondensation catalyst> When the oligomer obtained by the esterification reaction of the diol component and the dicarboxylic acid component is polycondensed, 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 esterification reaction and then directly subjected to the polycondensation reaction, or they may not be used in the esterification 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 esterification reaction, and then appropriately added as the polycondensation reaction proceeds. In any case, in the present invention, the PTMG-copolymerized PBT finally obtained necessarily contains titanium and preferably a metal from Group 2A of the Periodic Table, the amounts of which will be described later.

[0050] Specific examples of titanium compounds include inorganic titanium compounds such as titanium oxide and titanium tetrachloride, titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, titanium phenolates such as tetraphenyl titanate, etc. 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.

[0051] In the case of a direct polymerization method using terephthalic acid, the titanium catalyst content in the raw PTMG copolymerized PBT and the PTMG copolymerized PBT of the present invention is preferably 5 to 100 ppm by mass of titanium atoms relative to the PTMG copolymerized PBT. 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 90 ppm or less, even more preferably 80 ppm or less, particularly preferably 60 ppm or less, especially preferably 50 ppm or less, and most preferably 40 ppm or less. When dimethyl terephthalate is used, the titanium atom content is preferably 30 to 300 ppm, more preferably 50 to 200 ppm, in terms of mass ratio relative to the PTMG copolymerized PBT. If the titanium content is too high, the color tone, hydrolysis resistance, and solution haze will deteriorate, and the number of fish eyes will increase in the resulting molded product, while if the titanium content is too low, the polymerization property will deteriorate.

[0052] Specific examples of the compound of a metal of Group 2A of the Periodic Table in the present invention 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. 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. 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.

[0053] The content of Group 2A metal in the raw material PTMG-copolymerized PBT and the PTMG-copolymerized PBT of the present invention is not particularly limited, but is preferably 3 to 150 ppm by mass of Group 2A metal atoms relative to the PTMG-copolymerized PBT. This amount is more preferably 5 ppm or more, and even more preferably 10 ppm or more. This amount is more preferably 50 ppm or less, even more preferably 40 ppm or less, particularly preferably 30 ppm or less, and most preferably 15 ppm or less. If the content of Group 2A metal is too high, color tone and hydrolysis resistance may deteriorate, while if it is too low, polymerization may deteriorate. When an acetate salt of a Group 2A metal is used, the acetic acid source enters the reaction system, so the amount of Group 2A metal in the PTMG-copolymerized PBT is preferably 15 ppm or less.

[0054] The molar ratio of titanium atoms to Group 2A metal atoms of the periodic table (Group 2A metal / titanium) contained in the raw material PTMG copolymerized PBT and the PTMG copolymerized PBT 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.

[0055] The content of metals such as titanium atoms in PTMG copolymerized PBT can be measured using methods such as atomic emission, atomic absorption, and inductively coupled plasma (ICP) after recovering the metals in the polymer using a method such as wet ashing.

[0056] In producing the starting PTMG copolymer PBT and the PTMG copolymer PBT of the present invention, in addition to the titanium compound and the Group 2A metal compound 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.

[0057] [Method of producing PTMG copolymer PBT of the present invention] An oligomer obtained by previously subjecting a dicarboxylic acid component containing DMT or TPA as a main component and a diol component containing BDO as a main component to an esterification or transesterification reaction is added to a polycondensation reaction tank containing the raw material PTMG-copolymerized PBT produced as described above, and further polycondensation is carried out to obtain the PTMG-copolymerized PBT of the present invention. In this case, the polycondensation reaction conditions and catalyst can be the same as those used in producing the starting material PTMG copolymerized PBT.

[0058] When the PTMG copolymer PBT of the present invention is produced by adding an oligomer to a polycondensation reaction tank in which the raw material PTMG copolymer PBT remains and further performing polycondensation, it is preferable that the oligomer to be added has the above-mentioned esterification reaction rate or transesterification reaction rate of about 90 to 99%, from the viewpoint of the polycondensation reactivity of the raw material PTMG copolymer PBT and the oligomer.

[0059] As described above, the oligomer of DMT or TPA and BDO used in producing the PTMG copolymerized PBT of the present invention is used in an amount such that the proportion of the starting PTMG copolymerized PBT is preferably 1 to 20% by mass relative to the total of the starting PTMG copolymerized PBT and the reaction product of DMT or TPA and BDO, and the lower limit of the proportion of the starting PTMG copolymerized PBT is preferably 2% by mass, more preferably 3% by mass, even more preferably 4% by mass, and most preferably 5% by mass, while the upper limit is preferably 15% by mass, more preferably 13% by mass, even more preferably 10% by mass, and most preferably 8% by mass. If this ratio is less than the lower limit, the anti-hinge effect tends to decrease, and if it exceeds the upper limit, the product tends to be susceptible to decomposition and oxidative degradation while waiting in the reaction vessel.

[0060] [Physical properties of PTMG copolymer PBT] When the PTMG copolymer PBT of the present invention is used for compounding or injection molding, the intrinsic viscosity of the PTMG copolymer 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, resulting in poor flowability and poor moldability. The intrinsic viscosity of the PTMG copolymer 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.

[0061] Furthermore, when the PTMG copolymer PBT pellets of the present invention are used for extrusion applications such as film, sheet, or filament, the intrinsic viscosity of the PTMG copolymer 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, even more 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.

[0062] The intrinsic viscosity of the PTMG copolymerized PBT can be determined by the method described in the Examples section below. [Example]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way as long as the gist of the invention is not exceeded. The methods for measuring the physical properties and evaluation items used in the following examples are as follows.

[0064] (1) Intrinsic viscosity (IV) of PTMG copolymerized PBT The viscosity was measured using an Ubbelohde viscometer according to the following procedure. Using a mixed solvent of phenol / tetrachloroethane (1 / 1 mass ratio), the number of seconds it took for a polymer solution with a concentration of 1.0 g / dL and the solvent alone to fall at 30° C. was measured and calculated using the following formula. IV=((1+4K H η sp ) 0.5 -1) / (2K H C) (However, η sp =η0-1, where η is the number of seconds the polymer solution falls, η0 is the number of seconds the solvent falls, C is the polymer solution concentration (g / dL), and K H is Huggins' constant, which we used as 0.33.)

[0065] (2) Titanium and Group 2A metal concentrations in PTMG copolymerized PBT PTMG copolymerized PBT was wet decomposed with high-purity sulfuric acid and nitric acid for the electronics industry, and the content of PBT was measured using a high-resolution ICP (Inductively Coupled Plasma)-MS (Mass Spectrometer) (manufactured by ThermoQuest).

[0066] (3) PTMG copolymerization amount The sample was dissolved in a mixed solvent of deuterated chloroform / hexafluoroisopropanol (7 / 3 mass ratio) containing a trace amount of tetramethylsilane, and then deuterated pyridine was added and the sample was transferred to an NMR sample tube. 1 H NMR spectra were measured. The actual copolymerization amount of PTMG is preferably within ±10%, more preferably within ±7%, even more preferably within ±5%, and most preferably within ±3% of the target copolymerization amount.

[0067] (4) Hinge characteristic test Using the manufactured PTMG copolymer PBT, hinged test specimens of the size and shape shown in Figure 1(a) (plan view), Figure 1(b) (side view), and Figure 1(c) (enlarged side view of hinge portion A in Figure 1(b)) were molded using a mold attached to a FUNAC50B injection molding machine. In Figures 1(a) to 1(c), 1 and 2 are the main body of the molded product, 3 is the hinge portion, and G is the gate. The dimensions of the test specimens are in centimeters. The molding conditions were as follows: Cylinder temperature: 225℃ Mold temperature: 50℃ Injection pressure: 86MPa Injection speed: 120mm / sec Injection time: 6 seconds Cooling time: 7 seconds Test: The hinged test piece obtained by the above method was bent 180 degrees at the hinge, as shown in the enlarged side view in Figure 1(d), and the appearance of the hinge after bending was visually observed from the direction of the arrow and rated on a five-point scale as shown below. In the following, "turned up" means that the part of the hinge after bending that was visually observed had local cracks or peeling, making the surface uneven. The hinge property test was carried out on five test pieces at each temperature (23°C, 0°C), and the appearance evaluation results were scored on a five-point scale. The total score of the five test pieces was used as the overall score. The higher the overall score, the better the hinge property was judged to be. 10 points: No abnormalities at all 5 points: Partial peeling is observed 3 points: Peeling is observed on the entire surface 2 points: Some cracks are observed 0 points: Cracks are observed

[0068] (5) Lock strength (flexural modulus) The lock strength of a molded product is the stress when the molded piece deforms and the lock is released. If the molded piece is soft, it will be more likely to deform. Therefore, harder molded pieces have higher lock strength. For this reason, the lock strength is determined using the flexural modulus, with a flexural modulus of 2000 MPa or more being usable (○) and less than 2000 MPa being unusable (×) as an alternative evaluation. Using the produced PTMG copolymerized PBT, ISO bending test pieces were molded in an injection molding machine (Sumitomo Heavy Industries, Ltd., model S-75MIII) at a cylinder temperature of 250°C and a mold temperature of 80°C, in the same manner as for the bending properties ISO tensile test pieces, and the bending modulus was measured in accordance with ISO178.

[0069] [1,4-butanediol] [Example of biomass-derived 1,4-butanediol production] <Production Example 1: 1,4-Butanediol by Hydrogenation of Biomass-Derived Succinic Acid Ester> A mixture was obtained by mixing BDO manufactured by Yuanli Chemical Group and BDO manufactured by Zhejiang Boju New Materials Co., Ltd. The mixture was distilled under reduced pressure to obtain a first fraction, a main fraction, and a second fraction in the order of distillation. A portion of the main fraction was extracted and analyzed by gas chromatography, which revealed that the 1,4-butanediol content was 99% by mass or more.

[0070] [Example of chemically recycled 1,4-butanediol production] <Production Example 2: 1,4-Butanediol by Depolymerization of PBT> Chemically recycled BDO was produced in accordance with Example 3 of JP-A-2004-323378. An autoclave equipped with a stirring blade was charged with 1,030 parts by mass of polybutylene terephthalate, 3,200 parts by mass of methanol, and 13 parts by mass of sodium carbonate. The autoclave was immersed in an oil bath at 200°C, and the mixture was reacted for 8 hours with stirring at a pressure of 1.3 MPa. The autoclave was removed from the oil bath and cooled to below 10°C with ice water to obtain a slurry. The resulting slurry was separated into solid and liquid 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, and subsequent fraction in the order of distillation. A portion of the obtained main fraction was extracted and analyzed by gas chromatography, which revealed that the 1,4-butanediol content was 99% by mass or more.

[0071] [Dimethyl terephthalate] [Example of chemically recycled dimethyl terephthalate production] <Production Example 3: Chemically recycled dimethyl terephthalate 1> Chemically recycled dimethyl terephthalate 1 was obtained as follows, 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, 100 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 depolymerization reaction solution 1. The obtained depolymerization reaction solution 1 was filtered while hot using a glass filter, yielding filtrate 1. To the obtained filtrate 1, 200 parts by mass of methanol and 0.5 parts by mass of sodium carbonate were added, and the mixture was reacted at 65° C. for 1 hour to obtain reaction liquid 2. The resulting reaction liquid 2 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 to obtain a slurry. The resulting slurry 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 to obtain a white solid (chemically recycled dimethyl terephthalate 1). 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.

[0072] <Production Example 4: Chemically Recycled Dimethyl Terephthalate 2> Chemically recycled dimethyl terephthalate 2 was obtained as follows, 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. The temperature of the obtained depolymerization reaction liquid 1 was then lowered to room temperature, followed by the addition of xylene, 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 2) was extracted and analyzed by gas chromatography, revealing that the dimethyl terephthalate content was 99% by mass or more.

[0073] <Production Example 5: Chemically Recycled Dimethyl Terephthalate 3> Chemically recycled dimethyl terephthalate 3 was obtained as follows, with reference to the method described in JP-A-2001-151934. An autoclave equipped with a stirrer and thermometer was charged with 100 parts by mass of glass filler-containing polybutylene terephthalate and 200 parts by mass 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 the white solid contained in the solid fraction. The glass filler was removed as a filtrate by filtration to obtain solution 1. The resulting solution 1 was placed in a flask equipped with a fraction collection receiver, a stirrer, and a thermometer and then immersed in the oil bath. The temperature and pressure of the oil bath were controlled while monitoring the distillate, and the light-boiling components containing tetrahydrofuran, the initial fraction, the main fraction, and the bottoms were obtained in the order of distillation. A portion of the obtained main fraction (chemically recycled dimethyl terephthalate 3) was extracted and analyzed by gas chromatography, and it was found that the content of dimethyl terephthalate was 99 mass % or more.

[0074] [Terephthalic acid] [Example of chemically recycled terephthalic acid production] <Production Example 6: Chemically Recycled Terephthalic Acid 1> In the same manner as in Production Example 3, a white solid of dimethyl terephthalate (chemically recycled dimethyl terephthalate 1) having a dimethyl terephthalate content of 99% by mass or more was obtained. The resulting white solid of dimethyl terephthalate 1 was dissolved in methylene chloride, and a methanol solution of potassium hydroxide was added thereto for hydrolysis, yielding reaction liquid 1. The resulting reaction liquid 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 chemically recycled terephthalic acid 1 as a white solid. A portion of the resulting white solid (chemically recycled terephthalic acid 1) was analyzed by liquid chromatography, and the terephthalic acid content was found to be 99% by mass or more.

[0075] <Production Example 7: Chemically Recycled Terephthalic Acid 2> A main fraction having a dimethyl terephthalate content of 99% by mass or more was obtained in the same manner as in Production Example 4. This main fraction of dimethyl terephthalate (chemically recycled dimethyl terephthalate 2) was used instead of the white solid dimethyl terephthalate, and hydrolysis and purification were carried out in the same manner as in Production Example 6 to obtain chemically recycled terephthalic acid 2 as a white solid having a terephthalic acid content of 99% by mass or more.

[0076] <Production Example 8: Chemically Recycled Terephthalic Acid 3> In the same manner as in Production Example 5, a main fraction containing 99% by mass or more of dimethyl terephthalate was obtained. Instead of the white solid dimethyl terephthalate, the main fraction of this dimethyl terephthalate (chemically recycled dimethyl terephthalate 3) was used, and hydrolysis and purification were carried out in the same manner as in Production Example 6, to obtain chemically recycled terephthalic acid 3 as a white solid having a terephthalic acid content of 99% by mass or more.

[0077] [Polytetramethylene ether glycol] [Example of PTMG production using biomass-derived BDO] <Production Example 9: Production of Polytetramethylene Ether Glycol A> Tetrahydrofuran was produced from 1,4-butanediol with reference to Example 1 of JP-A-61-40278. Polytetramethylene ether glycol was produced using the obtained tetrahydrofuran with reference to Example 1 of JP-A-2018-154673. One part by mass of 97% by mass sulfuric acid was placed in a flask equipped with a thermometer, a distillation tube, and a stirring blade, and the temperature was adjusted to 130°C. The main fraction (biomass-derived 1,4-butanediol) obtained in Production Example 1 was fed to the flask at a rate of 90 parts by mass per hour. 1,000 parts by mass of distillate a was obtained from the distillation tube. A portion of distillate a was analyzed by gas chromatography and found to contain 80% by mass of tetrahydrofuran. The obtained distillate a was placed in a flask equipped with a thermometer, a distillation tube, and a stirring blade, and potassium carbonate was added as a dehydrating agent, followed by heating to 70°C to obtain distillate b. A portion of the obtained distillate b was analyzed by gas chromatography, and it was found that the tetrahydrofuran content was 99% by mass or more. 600 parts by mass of the distillate b was fed into a 1 L fully jacketed separable flask equipped with a torque-measurable stirring blade and a thermometer. 43 parts by mass of fluorosulfuric acid was then added. The internal temperature was raised to 45°C, and the reaction was carried out at a stirring speed of 200 rpm for 5 hours. The torque of the stirring blade reached 3.10 kgf cm, and polymerization reaction solution 1 was obtained. 380 parts by mass of demineralized water was supplied to a 1 L full-jacketed separable flask equipped with a stirring blade and a thermometer, followed by the addition of the obtained polymerization reaction liquid 1. Stirring was continued for 2 hours at 90°C to obtain hydrolyzed liquid 2. 2 parts by mass of calcium hydroxide and 25 parts by mass of demineralized water were supplied to the obtained hydrolyzed liquid 2 and stirred. Stirring was stopped, the mixture was allowed to stand for 1 hour, and then the aqueous phase was removed to obtain oil phase 3. 13 g of calcium hydroxide was supplied to the obtained oil phase 3 to obtain neutralized liquid 4. The obtained neutralized liquid 4 was placed in an evaporator equipped with an oil bath, and the low-boiling components were distilled off under normal pressure at an oil bath temperature of 140°C to obtain bottoms 5. 240 parts by mass of toluene was supplied to the obtained bottoms 5, and the flask was again placed in an evaporator equipped with an oil bath, and the low-boiling components were distilled off under normal pressure at an oil bath temperature of 150°C to obtain bottoms 6. To the obtained residue 6, 4.5 parts by mass of diatomaceous earth was added, and the mixture was pressure filtered using a PTFE membrane filter with 0.5 μm openings to obtain filtrate 7. The obtained filtrate 7 was placed in an evaporator equipped with an oil bath and dried at a pressure of 3 Torr and an oil bath temperature of 140° C. to obtain polytetramethylene ether glycol A. A portion of the obtained polytetramethylene ether glycol A was analyzed by gel filtration chromatography, and the number average molecular weight (Mn) was found to be 1,054.

[0078] [Example of PTMG production using BDO derived from chemical recycling] <Production Example 10: Production of Polytetramethylene Ether Glycol B> Production Example 9 was carried out in the same manner as in Production Example 9, except that the main fraction (chemically recycled 1,4-butanediol) obtained in Production Example 2 was used instead of the biomass-derived 1,4-butanediol obtained in Production Example 1. The number average molecular weight (Mn) of the obtained polytetramethylene ether glycol B was 1,051.

[0079] [Raw materials used, etc.] The raw materials used other than those produced in the above production example are as follows. Petrochemical-derived terephthalic acid: High-purity terephthalic acid manufactured by PT Mitsubishi Chemical Indonesia Petrochemical-derived DMT: SKPetrochemical Petrochemical-derived BDO: BDO produced by Mitsubishi Chemical Corporation using the butadiene process Petrochemical-derived PTMG: Mitsubishi Chemical PTMG (number average molecular weight: 1000)

[0080] [Example 1] PTMG copolymerized PBT was produced as follows. A clean transesterification reactor, free of any residue, was charged with 802 parts by mass of petrochemical-derived DMT (manufactured by SK Petrochemical), 447 parts by mass of petrochemical-derived BDO (manufactured by Mitsubishi Chemical Corporation), and petrochemical-derived PTMG (manufactured by Mitsubishi Chemical Corporation, number-average molecular weight 1000) to yield 1000 parts by mass of polymer. 100 parts by mass of PTMG was measured and added using a flow meter via a pipe connected to the PTMG tank. Tetrabutyl titanate was added as a catalyst in the form of a BDO solution to yield a titanium metal equivalent of 33 ppm by mass relative to the polymer (PTMG copolymerized PBT). The liquid temperature in the reactor was then maintained at 150°C for 60 minutes, after which it was increased to 210°C over 90 minutes and maintained at 210°C for 30 minutes. The transesterification reaction was carried out for a total of 180 minutes, during which the resulting methanol was distilled off.

[0081] Fifteen minutes before the end of the transesterification reaction, magnesium acetate tetrahydrate was dissolved in BDO and added to the resulting polymer at 48 ppm by mass as magnesium metal. Furthermore, 0.15 parts by mass of a hindered phenol antioxidant (ADEKA Corporation, AO-60: pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] was added in the form of a BDO slurry. Subsequently, tetrabutyl titanate was added as a BDO solution in an amount that would result in 25 ppm by mass of titanium metal relative to the resulting polymer. The resulting mixture was then transferred to a clean, residue-free polycondensation reactor equipped with a stirrer, nitrogen inlet, heater, thermometer, distillation tube, and vacuum exhaust port, and the polycondensation reaction was carried out under reduced pressure.

[0082] The polycondensation reaction was carried out by gradually reducing the pressure in the tank from normal pressure to 0.4 KPa over 85 minutes and continuing at 0.4 KPa or less. The reaction temperature was maintained at 210°C for 15 minutes from the start of pressure reduction, and then increased to 240°C over 45 minutes and maintained at this temperature. The reaction was terminated when the specified stirring torque was reached. The polycondensation reaction took 150 minutes.

[0083] The pressure in the vessel was then restored from the reduced pressure state with nitrogen, and then pressurized for polymer discharge. The temperature of the heat medium in the die during discharge was set to 235°C, and the polymer was extruded from the die in the form of strands. The strands were then cooled in a cooling water tank, cut with a strand cutter, and pelletized. When 95% of 1,000 parts by mass of the polymer had been withdrawn from the polycondensation reaction tank, withdrawal was stopped. 50 parts by mass of PTMG-copolymerized PBT remained in the polycondensation reaction tank. The proportion of PTMG in the polymer was 10.0% by mass. In other words, the amount of PTMG copolymerized in the raw material PTMG-copolymerized PBT was 10% by mass.

[0084] Next, 467 parts by mass of BDO were added to 839 parts by mass of dimethyl terephthalate shown in Table 1 in the transesterification reaction tank. This resulted in 950 parts by mass of homo-PBT. Subsequently, in the same manner as described above, a transesterification reaction and a polycondensation reaction were carried out in the polycondensation reaction tank in which the raw material PTMG copolymerized PBT remained. The transesterification reaction rate of the oligomer obtained in the transesterification reaction (oligomer charged into the polycondensation reaction tank) was 95%. The resulting mixture was extruded from the die head in the form of a strand and cut with a rotary cutter to obtain PTMG-copolymerized PBT pellets (major axis: approximately 3 mm, minor axis: approximately 2 mm, length: approximately 4 mm). The intrinsic viscosity (IV) of the resulting PTMG-copolymerized PBT was 0.85 dL / g. The proportion of PTMG in the polymer was 0.5% by mass, i.e., the amount of PTMG copolymerized was 0.5% by mass. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Table 1.

[0085] [Example 2] An ester exchange reaction was carried out in the same manner as in Example 1, except that 722 parts by mass of petrochemical-derived DMT (manufactured by SK Petrochemical), 402.1 parts by mass of petrochemical-derived BDO (manufactured by Mitsubishi Chemical Corporation), and petrochemical-derived PTMG (manufactured by Mitsubishi Chemical Corporation, average molecular weight 1000) were used to make 1000 parts by mass of polymer, and 200 parts by mass of PTMG was measured using a flow meter and added to a pipe connected to the PTMG tank. Subsequently, PTMG copolymerized PBT was obtained and a portion was extracted according to the details shown in Table 1. The amount of PTMG copolymerized in the extracted PTMG copolymerized PBT was 20.0 mass %. Thereafter, the PTMG copolymerized PBT remaining in the polycondensation reaction tank was used as the raw material PTMG copolymerized PBT to obtain a product PTMG copolymerized PBT in the same manner as in Example 1. The intrinsic viscosity (IV) of the product PTMG copolymerized PBT was 0.85 dL / g, and the amount of PTMG copolymerized was 1.0 mass%. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Table 1.

[0086] [Example 3] A raw material PTMG copolymerized PBT was produced in the same manner as in Example 2, and a portion thereof was extracted as shown in Table 1. Subsequently, 442 parts by mass of BDO was added to 794 parts by mass of dimethyl terephthalate shown in Table 1 in the transesterification reaction tank. This resulted in 900 parts by mass of homo-PBT. Subsequently, transesterification reaction and polycondensation reaction were carried out in the same manner as described above. The transesterification reaction rate of the oligomer obtained in the transesterification reaction (oligomer charged into the polycondensation reaction tank) was 95%. The resulting strand was then extruded from the die head and cut with a rotary cutter to obtain PBT pellets (major axis approximately 3 mm, minor axis approximately 2 mm, length approximately 4 mm). The intrinsic viscosity (IV) of the PTMG-copolymerized PBT produced was 0.86 dL / g, and the amount of PTMG copolymerized was 2.0% by mass. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Table 1.

[0087] [Examples 4 to 14] A raw material PTMG copolymerized PBT was produced in the same manner as in Example 2, except that the raw materials were changed as shown in Tables 1 and 2, and then a production PTMG copolymerized PBT was produced. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Tables 1 and 2.

[0088] [Example 15] A slurry of 617 parts by mass of petroleum-derived terephthalic acid (manufactured by Toray Industries, Inc.) and 603 parts by mass (1.80 molar ratio) of petroleum-derived BDO (manufactured by Mitsubishi Chemical Corporation) was added to a clean esterification reactor free of residues, to give a polymer of 1000 parts by mass. Next, 469 parts by mass (1.4 molar ratio) of the same BDO was added, and 200 parts by mass of petroleum-derived PTMG (manufactured by Mitsubishi Chemical Corporation, number average molecular weight 1000) was added using a flow meter from a pipe connected to the PTMG tank. The esterification reaction vessel was charged with a BDO solution containing a tetrabutyl titanate catalyst in an amount that resulted in 40 ppm of titanium in the PTMG copolymerized PBT. The temperature of the liquid in the vessel was raised from 150°C to 220°C over 90 minutes and maintained at 220°C for 60 minutes. During this time, the generated water was distilled off, and the esterification reaction was carried out for a total of 180 minutes. Fifteen minutes before the end of the esterification reaction, magnesium acetate tetrahydrate was dissolved in BDO and added so that the magnesium metal was 10 ppm by mass relative to the polymer produced. The mixture was then transferred to a clean, residue-free polycondensation reactor equipped with a stirrer, nitrogen inlet, heater, thermometer, distillation tube, and vacuum exhaust port, and the polycondensation reaction was carried out under reduced pressure.

[0089] The polycondensation reaction was carried out by gradually reducing the pressure in the tank from normal pressure to 0.4 KPa over 85 minutes and then maintaining it at 0.4 KPa or less. The reaction temperature was maintained at 220°C for 15 minutes from the start of pressure reduction, and then increased to 240°C over 45 minutes and maintained at this temperature. The reaction was terminated when the specified stirring torque was reached. The polycondensation reaction took 150 minutes.

[0090] The inside of the polycondensation reactor was then restored to pressure with nitrogen, and then pressurized for polymer discharge. The temperature of the heat medium in the die during discharge was set to 235°C, and the polymer was extruded from the die in the form of a strand. The strand was then cooled in a cooling water tank, cut with a strand cutter, and pelletized. When 95% of 1000 parts by mass of the polymer had been withdrawn from the polycondensation reaction tank, withdrawal was stopped. 50 parts by mass of PTMG-copolymerized PBT remained in the polycondensation reaction tank. The proportion of PTMG in the polymer was 20.0% by mass. In other words, the amount of PTMG copolymerized in the raw material PTMG-copolymerized PBT was 20.0% by mass.

[0091] Subsequently, a slurry containing 717 parts by mass of petroleum-derived terephthalic acid and 701 parts by mass (1.80 molar ratio) of petroleum-derived BDO (manufactured by Mitsubishi Chemical Corporation) was added to the esterification reaction tank. Next, 545 parts by mass (1.4 molar ratio) of the same BDO was added, and a transesterification reaction and a polycondensation reaction in the polycondensation reaction tank containing the remaining raw material PTMG copolymerized PBT were carried out in the same manner as described above. The transesterification reaction rate of the oligomer obtained in the esterification reaction (oligomer introduced into the polycondensation reaction tank) was 96%. The resulting strand was then removed from the die head and cut with a rotary cutter to obtain PTMG-copolymerized PBT pellets (major axis approximately 3 mm, minor axis approximately 2 mm, length approximately 4 mm). The intrinsic viscosity (IV) of the resulting PBT was 0.85 dL / g. The proportion of PTMG in the polymer was 1.0% by mass, i.e., the amount of PTMG copolymerized in the produced PTMG-copolymerized PBT was 1.0% by mass. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Table 3.

[0092] [Examples 16 to 26] A PTMG-copolymerized PBT was produced in the same manner as in Example 15, except that the raw materials were changed as shown in Tables 3 and 4. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Tables 3 and 4.

[0093] [Comparative Example 1] To a clean transesterification reactor free of residues, 843 parts by mass of petrochemical-derived DMT (manufactured by SK Petrochemical), 469 parts by mass of petrochemical-derived BDO (manufactured by Mitsubishi Chemical Corporation), and petrochemical-derived PTMG (manufactured by Mitsubishi Chemical Corporation; number average molecular weight 1000) were used to make 1000 parts by mass of polymer, and 50 parts by mass of PTMG was measured using a flow meter and added to a pipe connected to the PTMG tank. Thereafter, transesterification and polycondensation reactions were carried out to obtain PTMG copolymerized PBT in the same manner as in Example 1. The intrinsic viscosity (IV) of the obtained PTMG copolymerized PBT was 0.88 dL / g, and the amount of PTMG copolymerized was 5.1 mass%. The evaluation results of the obtained PTMG copolymerized PBT are summarized in Table 4.

[0094] Comparative Example 2 Five parts by mass of the raw material PTMG copolymerized PBT with a PTMG copolymerization amount of 20.0% by mass obtained in Example 2 and 95 parts by mass of PBT "Novaduran 5008" manufactured by Mitsubishi Chemical Corporation were charged into a blender and mixed uniformly to prepare a mixture. The resulting mixture was melt-kneaded at 260°C using a vented twin-screw extruder with a screw diameter of 30 mm (TEX30C manufactured by The Japan Steel Works, Ltd.), extruded into strands, and pelletized. The evaluation results of the obtained PTMG copolymerized PBT composition are summarized in Table 4.

[0095] In Tables 1 to 4, "residual residue carried in" in the production method column refers to a production method in which an oligomer is further added to the raw material PTMG copolymer PBT remaining in the polycondensation reaction tank, and "pipe addition" refers to a production method in which the produced PTMG copolymer PBT is directly manufactured without going through the raw material PTMG copolymer PBT. In addition, in the column for the produced PTMG copolymerized PBT, the "target PTMG copolymerization amount" is the PTMG copolymerization amount calculated from the raw material charge amount, the "analyzed PTMG copolymerization amount" is the PTMG copolymerization amount determined by analyzing the produced PTMG copolymerized PBT, and the "actual / charge ratio" is the ratio (percentage) of the analyzed PTMG copolymerization amount to the target PTMG copolymerization amount. Furthermore, for the "accuracy of the PTMG copolymerization amount," a "good" was given if the "actual / charge ratio" value was within ±3%. In Tables 1 to 4, raw materials derived from petroleum are indicated as "petroleum," raw materials derived from biomass are indicated as "bio," and raw materials derived from chemical recycling are indicated as "CR." "CR1," "CR2," and "CR3" in the TPA column represent "chemical recycled terephthalic acid 1," "chemical recycled terephthalic acid 2," and "chemical recycled terephthalic acid 3," respectively. "CR1," "CR2," and "CR3" in the DMT column represent "chemically recycled dimethyl terephthalate 1," "chemically recycled dimethyl terephthalate 2," and "chemically recycled dimethyl terephthalate 3," respectively.

[0096] [Table 1]

[0097] [Table 2]

[0098] [Table 3]

[0099] [Table 4]

[0100] It is clear from Tables 1 to 4 that the PTMG copolymer PBT of the present invention has stable and excellent hinge properties and high lock strength. It is also clear that the method for producing the PTMG copolymer PBT of the present invention makes it possible to produce the desired PTMG copolymer PBT with a low PTMG copolymerization amount with high precision. In contrast, in Comparative Example 1, in which the PTMG copolymerized PBT was produced without going through the raw material PTMG copolymerized PBT, the lock strength was poor. Furthermore, in the compound of PTMG copolymerized PBT and homo-PBT, as in Comparative Example 2, the hinge properties are poor. [Explanation of symbols]

[0101] 1,2 Molded product body 3 Hinge part G Gate< / ptmg> < / bdo>

Claims

1. a polytetramethylene ether glycol copolymerized polybutylene terephthalate obtained by copolymerizing 7 to 32 mass% of polytetramethylene ether glycol having a number average molecular weight of 650 to 2000; a reaction product of dimethyl terephthalate or terephthalic acid with 1,4-butanediol; is reacted with A polytetramethylene ether glycol copolymerized polybutylene terephthalate composition having a polytetramethylene ether glycol copolymerization amount of 0.1 to 2.0 mass %.

2. 2. The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to claim 1, wherein the amount of the polytetramethylene ether glycol copolymerized polybutylene terephthalate used is 1 to 20 mass% based on the total amount of the polytetramethylene ether glycol copolymerized polybutylene terephthalate and the reaction product of dimethyl terephthalate or terephthalic acid with 1,4-butanediol.

3. 2. The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to claim 1, wherein the dimethyl terephthalate is derived from petroleum, chemical recycling, or biomass.

4. 2. The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to claim 1, wherein the terephthalic acid is derived from petroleum, chemically recycled, or biomass.

5. 2. The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to claim 1, wherein the 1,4-butanediol is derived from petroleum, chemical recycling, or biomass.

6. 2. The polytetramethylene ether glycol copolymerized polybutylene terephthalate composition according to claim 1, wherein the polytetramethylene ether glycol is derived from petroleum, chemically recycled, or biomass.

7. A method for producing a polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition, comprising producing the polytetramethylene ether glycol-copolymerized polybutylene terephthalate in a polycondensation reaction tank, extracting a portion of the produced polytetramethylene ether glycol-copolymerized polybutylene terephthalate from the polycondensation reaction tank, and using the polycondensation reaction tank in which the remainder of the polytetramethylene ether glycol-copolymerized polybutylene terephthalate remains to produce the polytetramethylene ether glycol-copolymerized polybutylene terephthalate composition.

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