Polyester and method for producing the same

Abstract

To provide a polyester which exhibits a balance of flexibility and tensile fracture resistance, using polyether polyol as a copolymer component.SOLUTION: A polyester has a polymethyleneoxy-polyalkyleneoxy group with the content of repeating units of methyleneoxy (-CH2-O-) being more than 0 mol% and less than 50 mol%. It is preferable that the polymethyleneoxy-polyalkyleneoxy group is represented by the following formula (1). (In the formula, R is a divalent hydrocarbon group having 2 or more carbon atoms, and n, m, and s are each independently integers of 1 or more).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester and a method for producing the same, and more particularly to a polymethyleneoxypolyalkylene copolymer polyester which has improved flexibility and tensile break resistance while suppressing thermal decomposition during molding, and a method for producing the same. [Background technology]

[0002] Polyesters occupy an important position industrially due to their excellent mechanical and chemical properties. For example, aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate (PBT) are resins with excellent heat and chemical resistance, and because of their ease and economical molding processability, they are widely used in fields such as extrusion molding and injection molding for fibers, films, sheets, bottles, electrical and electronic components, automotive parts, and precision instrument parts.

[0003] In recent years, there has been a demand for polyesters that retain the basic properties of polyester while being endowed with new functions such as flexibility and tensile break resistance. It is known that the flexibility of polyester can be improved by incorporating polyether polyols such as polytetramethylene ether glycol (PTMG) as copolymerization components, but there are limits to the flexibility improvement effect, and it has been difficult to achieve both high flexibility and tensile break resistance.

[0004] Patent Document 1 describes a polyester containing a polymethyleneoxypolyalkyleneoxy group. The polyester described in Patent Document 1 is a polymethyleneoxypolyalkyleneoxy group represented by -AOR of formula (I). 1 In -O-, the content of repeating units corresponding to methyleneoxy (-CH2-O-) is at least 50 mol%, preferably at least 80 mol%, particularly at least 90 mol% of the total A, and Patent Document 1 does not describe the effect of reducing the content of repeating units of methyleneoxy (-CH2-O-). That is, Patent Document 1 addresses the problem of modifying polyacetal, and Patent Document 1 states that the higher the content of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group, the more preferable it is, but there is no description whatsoever suggesting that any effect can be obtained by reducing this content. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2007-504332 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above-mentioned conventional techniques, an object of the present invention is to provide a polyester using a polyether polyol as a copolymerization component, which can achieve both flexibility and tensile break resistance. [Means for solving the problem]

[0007] As a result of intensive research into the above-mentioned problems, the present inventors have discovered that these problems can be overcome by using a polyether polyol containing an oxymethylene group and controlling the content ratio of oxymethylene repeating units, and have arrived at the present invention. That is, the gist of the present invention is as follows.

[0008] [1] A polyester having a polymethyleneoxypolyalkyleneoxy group in which the content of methyleneoxy (—CH2—O—) repeating units is more than 0 mol% and less than 50 mol%.

[0009] [2] The polyester according to [1], wherein the polymethyleneoxypolyalkyleneoxy group is represented by the following formula (1):

[0010] [ka]

[0011] (In the formula, R is a divalent hydrocarbon group having 2 or more carbon atoms. n, m, and s are each independently an integer of 1 or more.)

[0012] [3] The polyester according to [1] or [2], wherein the content of repeating units of methyleneoxy (—CH2—O—) in the polymethyleneoxypolyalkyleneoxy group is less than 30 mol %.

[0013] [4] The polyester according to any one of [1] to [3], wherein the content of diol components in which a hydroxyl group is bonded to the carbon atom-side end of the polymethyleneoxypolyalkyleneoxy group and a hydrogen atom is bonded to the oxygen atom-side end of the polymethyleneoxypolyalkyleneoxy group is less than 5 mol % of all diol components constituting the polyester.

[0014] [5] The polyester according to any one of [1] to [4], wherein the number average molecular weight of the polymethyleneoxypolyalkyleneoxy group is more than 1,000 but less than 3,000.

[0015] [6] The polyester according to any one of [2] to [5], wherein R in the formula (1) is an n-butylene group.

[0016] [7] The polyester according to any one of [1] to [6], wherein the dicarboxylic acid component constituting the polyester contains a terephthalic acid component.

[0017] [8] The polyester according to any one of [1] to [7], wherein the diol component constituting the polyester contains a diol having a hydroxyl group bonded to the carbon atom side end of a polymethyleneoxypolyalkyleneoxy group and a hydrogen atom bonded to the oxygen atom side end, and 1,4-butanediol.

[0018] [9] A method for producing a polyester according to any one of [1] to [8], comprising charging a diol having a hydroxyl group bonded to the carbon atom-side end of a polymethyleneoxypolyalkyleneoxy group and a hydrogen atom bonded to the oxygen atom-side end thereof, a diol other than the diol, and a dicarboxylic acid and / or an ester-forming derivative thereof into a reaction vessel, and carrying out a transesterification reaction and / or an esterification reaction and a polycondensation reaction to produce the polyester according to any one of [1] to [8]. [Effects of the Invention]

[0019] According to the present invention, a polyester having excellent flexibility and tensile break resistance can be provided. That is, in the present invention, in a polyester using a polyether polyol as a copolymerization component, flexibility is increased by introducing an oxymethylene (-CH2-O-) repeating unit into the polyether polyol skeleton, and further, high tensile break resistance can be achieved by setting the content of oxymethylene repeating units in the polyether polyol skeleton to more than 0 mol% and less than 50 mol%. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following describes in detail the embodiments of the present invention. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not go beyond the gist of the present invention. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0021] In this specification, the term "mainly composed of" means that the component accounts for 70 mol % or more of the component. For example, "a dicarboxylic acid component containing a terephthalic acid component as a main component" means that 70 mol % or more of all dicarboxylic acid components constituting the polyester are terephthalic acid components. The term "dicarboxylic acid component" is also used to mean "a structural unit derived from the dicarboxylic acid component and incorporated into the polymethyleneoxypolyalkylene copolymer polyester." The same applies to the terms "diol component" and "polyether polyol component."

[0022] The polymethyleneoxypolyalkylene copolyester of the present invention may be used as a composition mixed with a polyester not containing a polyether polyol component.

[0023] [polyester] The polyester of the present invention is a polyester having polymethyleneoxypolyalkyleneoxy groups in which the content of methyleneoxy (—CH—O—) repeating units is more than 0 mol% and less than 50 mol% (hereinafter, sometimes referred to as “the polymethyleneoxypolyalkylene copolyester of the present invention” or “the polyester of the present invention”).

[0024] <Mechanism> In the present invention, in a polyester using a polyether polyol as a copolymerization component, by introducing polymethyleneoxypolyalkyleneoxy groups in which the content of oxymethylene repeating units is more than 0 mol% but less than 50 mol%, it is possible to improve both flexibility and tensile break resistance. Although the details of this mechanism are not clear, the inventors have found, as a result of extensive research, that the flexibility of conventional polyether polyol-incorporated polyesters, which had limited improvement potential, can be further improved by introducing a polymethyleneoxypolyalkyleneoxy group, which combines a methyleneoxy group with a polyether polyol. On the other hand, if the number of methyleneoxy repeating units is too large, the thermal stability of the raw material diol used for this purpose will be poor, and this raw material diol will thermally decompose during the transesterification reaction or esterification reaction and the subsequent polycondensation reaction during polyester production, and the diol component / dicarboxylic acid component ratio in the system will deviate from 1 / 1, preventing an increase in the degree of polymerization and resulting in a low tensile break resistance of the resulting polyester. In the present invention, by introducing polymethyleneoxypolyalkyleneoxy groups in which the repeating oxymethylene unit is more than 0 mol % but less than 50 mol % into polyester, it is possible to achieve both high flexibility and high tensile break resistance.

[0025] The aforementioned Patent Document 1 describes a polyester having a polymethyleneoxypolyalkyleneoxy group, but the problem in this Patent Document 1 is modification of polyacetal, which is different from the problem set by the present invention. In addition, Patent Document 1 does not describe or suggest at all that a high content of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group results in poor thermal stability of the raw material diol, or that reducing the content of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group can improve the thermal stability of the raw material diol and suppress decomposition of the raw material diol during the esterification or transesterification reaction and the subsequent polycondensation reaction. Therefore, the present invention cannot be easily arrived at from Patent Document 1.

[0026] <Polymethyleneoxypolyalkyleneoxy group> First, the polymethyleneoxypolyalkyleneoxy group contained in the polymethyleneoxypolyalkylene copolyester of the present invention (hereinafter, sometimes referred to as "the polymethyleneoxypolyalkyleneoxy group of the present invention") will be described.

[0027] The polymethyleneoxypolyalkyleneoxy group of the present invention typically has a content of methyleneoxy (—CH—O—) repeating units of more than 0 mol% and less than 50 mol%, and the content of methyleneoxy repeating units is preferably more than 0 mol% and less than 40 mol%, more preferably more than 0 mol% and less than 30 mol%, and even more preferably more than 0 mol% and less than 25 mol%. By increasing the content of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group to more than 0 mol%, high flexibility can be imparted. Furthermore, by reducing the content of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group to less than 50 mol%, thermal decomposition during the transesterification or esterification reaction and the subsequent polycondensation reaction of the polymethyleneoxypolyalkylene component used as a raw material for the polyester can be suppressed, thereby increasing the degree of polymerization and imparting high tensile break resistance.

[0028] The polymethyleneoxypolyalkyleneoxy group of the present invention is preferably a polymethyleneoxypolyalkyleneoxy group represented by the following formula (1) from the viewpoint of imparting high flexibility and tensile resistance to break.

[0029] [ka]

[0030] (In the formula, R is a divalent hydrocarbon group having 2 or more carbon atoms. n, m, and s are each independently an integer of 1 or more.)

[0031] In terms of improving flexibility, increasing the affinity between a polymethyleneoxypolyalkylene component (described later) and other components when producing the polymethyleneoxypolyalkylene copolymer polyester of the present invention, and improving tensile resistance to break, R in the formula (1) is preferably a divalent aliphatic hydrocarbon group having 2 to 15 carbon atoms, and more preferably a divalent acyclic aliphatic hydrocarbon group having 2 to 15 carbon atoms.

[0032] Examples of the divalent acyclic aliphatic hydrocarbon group having 2 to 15 carbon atoms include divalent hydrocarbon groups derived from linear polyols such as ethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; 2-methyl-1,3-propanediol; 2,2-dimethyl-1,3-propanediol (neopendiol); Examples of the divalent hydrocarbon groups include divalent hydrocarbon groups derived from branched polyols such as 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1,6-hexanediol, 3-butyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2,2-dibutyl-1,3-propanediol. Among these, divalent hydrocarbon groups derived from 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are more preferred, and divalent hydrocarbon groups derived from 1,4-butanediol are particularly preferred.

[0033] Examples of divalent alicyclic hydrocarbon groups having 2 to 10 carbon atoms include 1,3-cyclopentanediol, 1,4-cyclohexanediol, erythritan, isosorbide, 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane, 1,3-cyclohexanedimethanol, 2,7-norbornanediol, tricyclo[5.2.1.0] 2,6

[0033] Examples include divalent hydrocarbon groups derived from alicyclic polyols such as decanedimethanol. Among these, divalent hydrocarbon groups derived from erythritan, isosorbide, and 1,4-cyclohexanedimethanol are more preferred.

[0034] In the polymethyleneoxypolyalkyleneoxy group of the present invention, R in the formula (1) is preferably an n-butylene group derived from 1,4-butanediol, that is, a tetramethylene group, particularly from the viewpoint of thermal stability during synthesis.

[0035] The R in the formula (1) is not limited to one type, and may contain two or more different types.

[0036] The number average molecular weight of the polymethyleneoxypolyalkyleneoxy group of the present invention is usually 200 to 100,000, preferably 600 to 6,000, and more preferably more than 1,000 and less than 3,000. By setting the number average molecular weight within the above range, it is possible to increase the affinity between the polymethyleneoxypolyalkylene component described below and other components when producing the polymethyleneoxypolyalkylene copolymer polyester of the present invention, and it is possible to obtain a polymethyleneoxypolyalkylene copolymer polyester that is excellent in tensile resistance to break and has an excellent balance between melting point and flexibility. The number average molecular weight (Mn) can be measured by GPC (gel permeation chromatography), as specifically described in the Examples section below.

[0037] The polymethyleneoxypolyalkyleneoxy group of the present invention is a polyether polyol (-(RO)) represented by the repeating unit n in the formula (1). n The number-average molecular weight of the polymethyleneoxypolyalkylene copolymer polyester of the present invention is preferably 100 to 3,000, more preferably 150 to 2,000, and even more preferably 250 to 1,000. By setting the number-average molecular weight to 3,000 or less, the affinity between the polymethyleneoxypolyalkylene component described below and other components during production of the polymethyleneoxypolyalkylene copolymer polyester of the present invention can be improved, thereby resulting in a polymethyleneoxypolyalkylene copolymer polyester with excellent tensile break resistance. Furthermore, by setting the number-average molecular weight to 100 or more, a polymethyleneoxypolyalkylene copolymer polyester with an excellent balance between melting point and flexibility can be obtained. The number average molecular weight (Mn) can be measured by GPC (gel permeation chromatography), as specifically described in the Examples section below.

[0038] The polymethyleneoxypolyalkylene copolymer polyester of the present invention may contain only one type of polymethyleneoxypolyalkyleneoxy group, or may contain two or more types of polymethyleneoxypolyalkyleneoxy groups that differ, for example, in the type of R in formula (1), the numbers of n and m, number average molecular weight, etc.

[0039] In the polymethyleneoxypolyalkylene copolymer polyester of the present invention, the content of the polymethyleneoxypolyalkyleneoxy group of the present invention is usually more than 0 mol% and not more than 99 mol%, preferably 0.5 to 50 mol%, more preferably 1.0 to 35.5 mol%, even more preferably 1.5 to 10 mol%, and particularly preferably 2 mol% or more and less than 5 mol%, based on the total diol components contained in the polymethyleneoxypolyalkylene copolymer polyester of the present invention. By setting the content ratio of polymethyleneoxypolyalkyleneoxy groups within the above range, thermal decomposition during molding can be suppressed, high tensile resistance to breakage can be obtained, and a polymethyleneoxypolyalkylene copolymer polyester with an excellent balance between flexibility and melting point can be obtained.

[0040] Furthermore, in the polymethyleneoxypolyalkylene copolyester of the present invention, the content of the methyleneoxy (—CH2-O—) repeating unit introduced as part of the polymethyleneoxypolyalkyleneoxy group is preferably more than 0 mol% and less than 25 mol%, particularly more than 0 mol% and less than 15 mol%, and especially more than 0 mol% and less than 1 mol%, based on the total diol components, from the viewpoint of achieving both flexibility and tensile break resistance. The content ratio of the methyleneoxy repeating unit to the total diol components is a value expressed as [POM]×100 / [(POM-PTMG)+BG] in the Examples section below.

[0041] [Polyester manufacturing method] The method for producing the polymethyleneoxypolyalkylene copolyester of the present invention will be described below.

[0042] [1] Raw material for polymethyleneoxypolyalkylene copolymer polyester The polymethyleneoxypolyalkylene copolymer polyester of the present invention can be obtained by subjecting a dicarboxylic acid component, a diol having a hydroxyl group bonded to the carbon atom-side end of the polymethyleneoxypolyalkyleneoxy group of the present invention and a hydrogen atom bonded to the oxygen atom-side end of the polymethyleneoxypolyalkyleneoxy group (hereinafter sometimes referred to as a "polymethyleneoxypolyalkylene component"), and a diol component other than this polymethyleneoxypolyalkylene component (hereinafter sometimes referred to as an "other diol component"), and other copolymerizable components used as needed, to a transesterification reaction and / or an esterification reaction, followed by a polycondensation reaction. A reaction catalyst can be used in the transesterification reaction and / or esterification reaction and polycondensation reaction.

[0043] (Dicarboxylic acid component) The dicarboxylic acid component of the present invention includes the dicarboxylic acids and their ester-forming derivatives described below. These may be produced by a petrochemical method and / or a production method including a fermentation step derived from biomass resources. Preferred ester-forming derivatives of dicarboxylic acids include lower alcohol esters of dicarboxylic acids, as well as ester-forming derivatives such as acid anhydrides and acid chlorides. Here, the term "lower alcohol" generally refers to a linear or branched alcohol in which the alkyl group has 1 to 4 carbon atoms.

[0044] The dicarboxylic acid component in the present invention is not particularly limited, but specifically includes: aliphatic chain dicarboxylic acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, and dodecanedicarboxylic acid, and ester-forming derivatives thereof; Alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, 1,4-cyclohexanedicarboxylic acid, and ester-forming derivatives of alicyclic dicarboxylic acids such as dimethyl 1,4-cyclohexanedicarboxylate (1,4-DMCD); Aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylketonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, and ester-forming derivatives of aromatic dicarboxylic acids such as methyl terephthalate (DMT), etc. Examples include:

[0045] In addition to the above, the ester-forming derivatives include anhydrides such as succinic anhydride and adipic anhydride.

[0046] Among these, from the viewpoint of the physical properties of the polyester obtained, aromatic dicarboxylic acids such as terephthalic acid and 2,6-naphthalenedicarboxylic acid, ester-forming derivatives of aromatic dicarboxylic acids such as terephthalic acid dimethyl ester (DMT) and 2,6-naphthalenedicarboxylic acid dimethyl ester (NDCE), alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, and ester-forming derivatives of alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylate dimethyl (1,4-DMCD) are preferred, and terephthalic acid components, i.e., terephthalic acid and ester-forming derivatives of terephthalic acid, are particularly preferred. The dicarboxylic acid component in the present invention preferably contains these as the main component.

[0047] These dicarboxylic acid components may be used singly or in combination of two or more.

[0048] (Other diol components) The other diol component in the present invention is not particularly limited, but examples thereof include: acyclic aliphatic diols such as ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butylene glycol (1,4-BG), 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, and polydecamethylene glycol; cycloaliphatic diols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol (1,4-CHDO), and 1,4-cyclohexanedimethanol (1,4-CHDM); aromatic diols such as xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone; Diols derived from plant materials such as isosorbide, isomannide, isoidet, and erythritan Examples include:

[0049] Ethylene glycol, 1,3-propanediol, 1,4-BG, and the like derived from biomass resources can also be used.

[0050] Among these, ethylene glycol, 1,4-BG, 1,4-CHDO, and 1,4-CHDM are preferred in terms of the physical properties of the resulting polyester, with 1,4-BG being particularly preferred. The other diol component in the present invention preferably contains these as the main component.

[0051] These other diol components may be used singly or in combination of two or more.

[0052] These other diol components in combination with the dicarboxylic acid component constitute the hard segments of the polymethyleneoxypolyalkylene copolyester of the present invention.

[0053] The amount of the other diol component is such that the total molar amount, including the polymethyleneoxypolyalkylene component described below, is approximately equal to the molar amount of the dicarboxylic acid component. When the polymethyleneoxypolyalkylene copolyester of the present invention contains "other copolymerizable components," the amount of the diol component is determined taking these amounts into consideration.

[0054] (Polymethyleneoxypolyalkylene component) The polymethyleneoxypolyalkylene component used in the production of the polymethyleneoxypolyalkylene copolyester of the present invention is a diol in which a hydroxyl group is bonded to the carbon atom side end of the polymethyleneoxypolyalkyleneoxy group of the present invention and a hydrogen atom is bonded to the oxygen atom side end, and is preferably a diol represented by the following formula (2):

[0055] [ka]

[0056] (In the formula, R is a divalent hydrocarbon group having 2 or more carbon atoms. n, m, and s are each independently an integer of 1 or more.)

[0057] With regard to the polymethyleneoxypolyalkylene component, the same explanations as given for the polymethyleneoxypolyalkyleneoxy group of the present invention apply to the content of repeating units of methyleneoxy groups and the number average molecular weight.

[0058] That is, the content of methyleneoxy (—CH2—O—) repeating units in the polymethyleneoxypolyalkylene component is usually greater than 0 mol% and less than 50 mol%, preferably greater than 0 mol% and less than 40 mol%, more preferably greater than 0 mol% and less than 30 mol%, and even more preferably greater than 0 mol% and less than 25 mol%. Having a content of methyleneoxy repeating units in the polymethyleneoxypolyalkylene component greater than 0 mol% can impart high flexibility to the resulting polymethyleneoxypolyalkylene copolyester. Furthermore, having a content of methyleneoxy repeating units in the polymethyleneoxypolyalkylene component less than 50 mol% can suppress thermal decomposition of the polymethyleneoxypolyalkylene component during the transesterification reaction or esterification reaction and polycondensation reaction, increasing the degree of polymerization and allowing for the production of a polymethyleneoxypolyalkylene copolyester with high tensile break resistance.

[0059] Furthermore, from the viewpoints of improving flexibility, increasing the affinity between the polymethyleneoxypolyalkylene component and other components, and improving tensile resistance to break, R in the formula (2) is preferably a divalent aliphatic hydrocarbon group having 2 to 10 carbon atoms, and more preferably a divalent acyclic aliphatic hydrocarbon group having 2 to 10 carbon atoms. Specific examples of these hydrocarbon groups are as exemplified in the polymethyleneoxypolyalkyleneoxy groups of the present invention, and the same applies to preferred examples.

[0060] The number average molecular weight of the polymethyleneoxypolyalkylene component is usually 200 to 100,000, preferably 600 to 6,000, and more preferably more than 1,000 and less than 3,000. By setting the number average molecular weight within the above range, it is possible to increase the affinity between the polymethyleneoxypolyalkylene component and other components, and to obtain a polymethyleneoxypolyalkylene copolyester that is excellent in tensile resistance to break and has an excellent balance between melting point and flexibility. The number average molecular weight (Mn) can be measured by GPC (gel permeation chromatography), as specifically described in the Examples section below.

[0061] The polyether polyol (-(RO)) represented by the repeating unit n in the formula (2) contained in the polymethyleneoxypolyalkylene component n The number-average molecular weight of the polymethyleneoxypolyalkylene copolymer polyester is preferably 100 to 3,000, more preferably 150 to 2,000, and even more preferably 250 to 1,000. By setting the number-average molecular weight to 3,000 or less, the affinity between the polymethyleneoxypolyalkylene component and other components is increased, thereby making it possible to obtain a polymethyleneoxypolyalkylene copolymer polyester with excellent tensile break resistance. Furthermore, by setting the number-average molecular weight to 100 or more, it is possible to obtain a polymethyleneoxypolyalkylene copolymer polyester with an excellent balance between melting point and flexibility. The number average molecular weight (Mn) can be measured by GPC (gel permeation chromatography), as specifically described in the Examples section below.

[0062] As shown in the synthesis examples in the Examples below, such polymethyleneoxypolyalkylene components can be produced by etherifying the terminal hydroxyl groups of a polyalkylene ether glycol, such as polytetramethylene ether glycol, whose alkylene group has 2 or more carbon atoms, preferably 2 to 10, with paraformaldehyde in the presence of a catalyst. In this production method, the molecular weight of the polyalkylene ether glycol used, i.e., the number concentration of the terminal hydroxyl groups of the polyalkylene ether glycol, can be adjusted to control the content of methyleneoxy repeating units. Furthermore, the number average molecular weight of the polymethyleneoxypolyalkylene component can be controlled by the number average molecular weight of the polyalkylene ether glycol used.

[0063] In the present invention, only one type of polymethyleneoxypolyalkylene component may be used, or two or more types, for example, two or more types of polymethyleneoxypolyalkylene components that differ in the type of R in formula (2), the numbers of n and m, number average molecular weight, etc., may be used.

[0064] In the polymethyleneoxypolyalkylene copolymer polyester of the present invention, the preferred content ratio of the polymethyleneoxypolyalkyleneoxy group of the present invention is as described above. Therefore, in producing the polymethyleneoxypolyalkylene copolymer polyester of the present invention, it is preferred to use more than 0 mol% and not more than 99 mol%, preferably 0.5 to 50 mol%, more preferably 1.0 to 35 mol%, even more preferably 1.5 to 10 mol%, and particularly preferably 2 mol% or more and less than 5 mol%, of the polymethyleneoxypolyalkylene component relative to all diol components used in producing the polymethyleneoxypolyalkylene copolymer polyester, for the same reasons as those for the polymethyleneoxypolyalkyleneoxy group of the present invention described above.

[0065] Furthermore, as described above, in the polymethyleneoxypolyalkylene copolymer polyester of the present invention, the content of methyleneoxy (—CH2-O—) repeating units introduced as part of the polymethyleneoxypolyalkyleneoxy groups is usually more than 0 mol% and less than 50 mol%, preferably more than 0 mol% and less than 40 mol%, more preferably more than 0 mol% and less than 30 mol%, and even more preferably more than 0 mol% and less than 25 mol%, based on the total diol components, from the viewpoint of achieving both flexibility and tensile break resistance. Therefore, in the polymethyleneoxypolyalkylene copolymer polyester of the present invention, it is preferable to determine the type and amount of polymethyleneoxypolyalkylene component used, based on the relationship between the amount of polymethyleneoxypolyalkylene component used and the content of methyleneoxy repeating units in the polymethyleneoxypolyalkylene component, so as to obtain a polymethyleneoxypolyalkylene copolymer polyester having the above content of methyleneoxy repeating units.

[0066] (Other copolymerizable components) The polymethyleneoxypolyalkylene copolyester of the present invention may contain other copolymerizable components as required in addition to the dicarboxylic acid component, other diol component and polymethyleneoxypolyalkylene component.

[0067] Other copolymerizable compounds that can be used as raw materials for the polymethyleneoxypolyalkylene copolymer polyester in the present invention include hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, and p-β-hydroxyethoxybenzoic acid; monofunctional carboxylic acids such as stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid, and benzoylbenzoic acid; trifunctional or higher polyfunctional carboxylic acids such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid, and gallic acid; and trifunctional or higher polyfunctional alcohols such as trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, and sugar esters. The other copolymerizable components may be used singly or in combination of two or more.

[0068] The amount of other copolymerizable components used, i.e., the content thereof in the polymethyleneoxypolyalkylene copolymer polyester of the present invention, is preferably less than 10 mol % relative to the total carboxylic acid components in the case of acids, and more preferably less than 5 mol % relative to the total alcohol components in the case of alcohols.

[0069] [2] Manufacturing method of polymethyleneoxypolyalkylene copolymer polyester The polymethyleneoxypolyalkylene copolymerized polyester of the present invention can be produced by a method in which a dicarboxylic acid component, other diol component, polymethyleneoxypolyalkylene component, and other copolymerizable components used as necessary are used as starting materials and are directly charged into a reaction vessel, and a polyester is obtained through a transesterification and / or esterification reaction step, a polycondensation reaction of the oligomer obtained by this reaction, and a polycondensation step in which solid-state polycondensation is further carried out as necessary.

[0070] (Transesterification and / or Esterification) In the present invention, in the first step, a transesterification reaction and / or an esterification reaction is carried out between a dicarboxylic acid component and another diol component and a polymethyleneoxypolyalkylene component.

[0071] Generally, the dicarboxylic acid component and the polymethyleneoxypolyalkylene component are not distilled off in the polycondensation reaction described below that follows the transesterification reaction and / or the esterification reaction, but some of the other diol components are distilled off in the polycondensation reaction and some are not. When using a diol component that is distilled off in the polycondensation reaction, it is preferable to use a total molar amount of diol, which is the sum of this diol component and the polymethyleneoxypolyalkylene component, that is slightly more than the molar amount of the dicarboxylic acid component, and after reacting all of the dicarboxylic acid component in the transesterification reaction and / or esterification reaction, to distill off the unreacted diol component during the polycondensation reaction. On the other hand, when using a diol component that is not distilled off in the polycondensation reaction, in order to sufficiently proceed with the polycondensation reaction, it is preferable that the molar amount of the total diol, which is the sum of the other diol components and the polymethyleneoxypolyalkylene component used, is approximately equal to the molar amount of the dicarboxylic acid component.

[0072] That is, when using a diol component such as 1,4-BG that is distilled off during the polycondensation reaction, the total amount of diol components used, including the other diol components and the polymethyleneoxypolyalkylene component, is preferably 1.1 to 3.0 mol, more preferably 1.1 to 1.5 mol, per mol of the dicarboxylic acid component. If this value is too small, the polycondensation reaction tends to proceed insufficiently, while if it is too large, the amount of THF produced by decomposition of 1,4-BG tends to increase. Furthermore, when using a diol component such as 1,4-CHDM that is not distilled off during the polycondensation reaction, the total amount of diol components used, including the other diol components and the polymethyleneoxypolyalkylene component, is preferably 0.9 to 1.1 mol, more preferably 0.98 to 1.02 mol, per mol of the dicarboxylic acid component. If this value is too small or too large, the polycondensation reaction tends to proceed insufficiently.

[0073] Examples of catalysts that can be used in this first-stage reaction include antimony compounds such as diantimony trioxide; germanium compounds such as germanium dioxide and germanium tetroxide; titanium compounds such as titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate; dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, and triethyltin. Examples of suitable catalysts include metal compounds containing atoms of Group 2A metals of the periodic table, such as tin compounds such as magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, and magnesium hydrogen phosphate; and calcium compounds such as calcium acetate, calcium hydroxide, calcium carbonate, calcium oxide, calcium alkoxide, and calcium hydrogen phosphate. These catalysts include manganese compounds and zinc compounds. Among these, metal compounds containing titanium atoms and atoms of Group 2A metals of the periodic table are preferred, with titanium compounds and tin compounds being more preferred, and tetrabutyl titanate being particularly preferred. These catalysts can be used alone or in combination.

[0074] These reaction catalysts are preferably added so that the concentration of metals derived from the reaction catalyst contained in the produced polymethyleneoxypolyalkylene copolyester falls within the following range. In the case of a transesterification reaction, the amount of these catalysts used is usually 1 to 300 ppm by mass, preferably 5 to 250 ppm by mass, more preferably 10 to 200 ppm by mass, particularly preferably 20 to 175 ppm by mass, and most preferably 25 to 150 ppm by mass, calculated as the metal content in the polymethyleneoxypolyalkylene copolymer polyester. In the case of an esterification reaction, the amount of these catalysts used is usually 1 to 300 ppm by mass, preferably 5 to 200 ppm by mass, more preferably 1 to 100 ppm by mass, particularly preferably 20 to 90 ppm by mass, and most preferably 30 to 70 ppm by mass, calculated as the metal content in the polymethyleneoxypolyalkylene copolymer polyester. When the amount of catalyst added in the transesterification reaction and / or esterification reaction, expressed as the metal content in the polymethyleneoxypolyalkylene copolymer polyester, is within the above range, the generation of foreign matter is suppressed, and the resulting polymethyleneoxypolyalkylene copolymer polyester is less likely to undergo deterioration reactions or gas generation during heat retention.

[0075] The reaction conditions for the transesterification reaction and / or esterification reaction are arbitrary as long as they allow the reaction to proceed, and the reaction temperature is usually 120° C. or higher, preferably 150° C. or higher, and usually 300° C. or lower, preferably 250° C. or lower, and more preferably 210° C. or lower. The reaction time is usually 2 to 8 hours, preferably 2 to 6 hours, and more preferably 2 to 4 hours.

[0076] The first stage reaction produces an oligomer in which the dicarboxylic acid component, the other diol component, and the polymethyleneoxypolyalkylene component have reacted.

[0077] (Polycondensation reaction) Next, the oligomer produced in the first stage is subjected to a polycondensation reaction (second stage reaction). The polycondensation reaction is usually carried out by a melt polycondensation reaction. The conditions for the melt polycondensation reaction are arbitrary as long as the reaction can proceed. The reaction temperature during the polycondensation reaction is preferably 200 to 300°C or less, more preferably 240 to 250°C. When the reaction temperature is equal to or less than the above upper limit, thermal decomposition reaction during production tends to be suppressed, and the color tone tends to improve. When the reaction temperature is equal to or more than the above lower limit, the polycondensation reaction tends to proceed efficiently.

[0078] The catalysts described for the transesterification reaction and / or the esterification reaction can be used as the polycondensation reaction catalyst. The catalyst used in the transesterification reaction and / or the esterification reaction may be used as the polycondensation reaction catalyst as is, or a further catalyst may be added. The amount of the catalyst added is preferably such that the metal-equivalent content of the polycondensation reaction catalyst in the polymethyleneoxypolyalkylene copolyester falls within the following range.

[0079] When polycondensation is carried out following the transesterification reaction, the amount of catalyst added is usually 5 to 300 ppm by mass, preferably 10 to 200 ppm by mass, more preferably 15 to 150 ppm by mass, particularly preferably 20 to 100 ppm by mass, and most preferably 30 to 50 ppm by mass, calculated as the metal content in the polymethyleneoxypolyalkylene copolymer polyester. When polycondensation is carried out following the esterification reaction, the amount of catalyst added is usually 0.5 to 300 ppm by mass, preferably 1 to 200 ppm by mass, more preferably 3 to 100 ppm by mass, particularly preferably 5 to 50 ppm by mass, and most preferably 10 to 40 ppm by mass, calculated as the metal content in the polymethyleneoxypolyalkylene copolymer polyester.

[0080] When the amount of catalyst added in the polycondensation reaction is within this range as the metal-equivalent content in the polymethyleneoxypolyalkylene copolymer polyester, the generation of foreign matter is suppressed, and the resulting polymethyleneoxypolyalkylene copolymer polyester is less likely to undergo deterioration reactions or gas generation during heat retention.

[0081] The lower the pressure inside the reaction vessel during the polycondensation reaction, the more easily the reaction proceeds, and in the final stage, it is usually 27 kPa or less, preferably 20 kPa or less, more preferably 13 kPa or less, and of these, it is preferable to maintain a state of 0.4 kPa or less in at least one polycondensation reaction vessel. The time required for the polycondensation reaction is adjusted so as to maintain a constant range of the intrinsic viscosity of the resulting polymethyleneoxypolyalkylene copolymer polyester, and is usually 2 to 12 hours, preferably 2 to 10 hours. When the polycondensation reaction is carried out continuously, the average residence time in the polycondensation reaction vessel is regarded as the time required for the polycondensation reaction.

[0082] In the present invention, the polymethyleneoxypolyalkylene component is added to the reaction system at the start of the transesterification reaction and / or esterification reaction, or during the period from the start of the transesterification reaction and / or esterification reaction to the end of the polycondensation reaction. Adding the polymethyleneoxypolyalkylene component during this period can increase the reaction rate of the polymethyleneoxypolyalkylene component and reduce the content of unreacted polymethyleneoxypolyalkylene component in the final product, which is preferable because it can prevent the unreacted polymethyleneoxypolyalkylene component from bleeding onto the product surface or adhering to the rolls during film formation.

[0083] After the polycondensation reaction is completed, the resulting polymer is extracted from the reaction vessel in the form of a strand and cut into pellets under or after water cooling. The pellets can be further polymerized to a higher degree by solid-phase polycondensation, if necessary.

[0084] The solid-phase polycondensation reaction is carried out under an inert gas atmosphere such as nitrogen, under reduced pressure, or under an inert gas flow. The reaction temperature is usually 180°C or higher, preferably 190°C or higher, and usually 210°C or lower, preferably 200°C or lower. The solid-phase polycondensation reaction is carried out for a relatively long period of time until the desired intrinsic viscosity is reached. The reaction time for solid-phase polycondensation is usually 5 to 20 hours, preferably 6 to 15 hours. The solid-phase polycondensation can be carried out batchwise or continuously.

[0085] [Physical properties of polymethyleneoxypolyalkylene copolymer polyester] Preferred physical properties of the polymethyleneoxypolyalkylene copolyester of the present invention are listed below, and the methods for measuring each property are as described in the Examples section below.

[0086] (intrinsic viscosity) The intrinsic viscosity (dL / g) of the polymethyleneoxypolyalkylene copolyester of the present invention is preferably 0.35 to 1.60, more preferably 0.50 to 1.55, and even more preferably 0.70 to 1.50. When the intrinsic viscosity is within this range, the moldability is good and the molded product has excellent physical properties.

[0087] (tensile modulus) The flexural modulus of the polymethyleneoxypolyalkylene copolyester of the present invention is usually designed to be about 200 to 2000 MPa, preferably 200 to 1300 MPa, and the smaller this value, the better the flexibility and the more preferable it is.

[0088] (Tensile elongation at break) The tensile breaking elongation of the polymethyleneoxypolyalkylene copolyester of the present invention is usually designed to be about 10 to 20%, preferably 12 to 20%, and the larger this value, the better the tensile breaking resistance and the more preferable it is.

[0089] [Polyester composition / molded body] The polymethyleneoxypolyalkylene copolymer polyester of the present invention may be blended with various additives such as stabilizers, antioxidants, fillers, antistatic agents, release agents, and flame retardants, or with PBT or other resins, as needed, to form a polyester composition. The polyester composition or the polyester of the present invention can also be used to form a molded article.

[0090] (Blending method) The method for blending the various additives and resins is not particularly limited. The various additives can be blended during or after the production of the polymethyleneoxypolyalkylene copolymer polyester of the present invention, and PBT and other resins can be blended after the production of the polymethyleneoxypolyalkylene copolymer polyester. When blending after the production of the polymethyleneoxypolyalkylene copolymer polyester, a method using a single-screw or twin-screw extruder equipped with a device for volatilization through a vent port as a kneader is preferred. The components can be fed to the kneader sequentially or all at once. Alternatively, two or more components selected from the respective components may be mixed in advance.

[0091] (Molding method) The polymethyleneoxypolyalkylene copolymerized polyester of the present invention and a polyester composition containing the same can be formed into various molded articles including filaments, fibers, sheets, films, etc. by molding methods commonly used for thermoplastic resins, i.e., molding methods such as injection molding, blow molding, extrusion molding, press molding, stretch molding, and inflation molding. The molded article obtained can have appropriate flexibility, for example, a tensile modulus of elasticity of 200 to 2000 MPa and a tensile breaking elongation of 10 to 20%, and can be suitably used in applications requiring flexibility and tensile breaking resistance. [Example]

[0092] 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.

[0093] The compounds described in the Synthesis Examples, Examples and Comparative Examples are abbreviated as follows: DMT: dimethyl terephthalate BG: 1,4-butanediol PTMG250: Polytetramethylene ether glycol with a number average molecular weight (Mn) of 250, manufactured by Mitsubishi Chemical Corporation PTMG650: Polytetramethylene ether glycol with a number average molecular weight (Mn) of 650, manufactured by Mitsubishi Chemical Corporation PTMG1000: Polytetramethylene ether glycol with a number average molecular weight (Mn) of 1000, manufactured by Mitsubishi Chemical Corporation PTMG2000: Polytetramethylene ether glycol with a number average molecular weight (Mn) of 2000, manufactured by Mitsubishi Chemical Corporation PFA: Paraformaldehyde TfOH: trifluoromethanesulfonic acid

[0094] [Measurement and evaluation method] The methods for measuring the physical properties and evaluation items used in the following examples are as follows.

[0095] <Intrinsic viscosity of polyether polyol copolymer polyester> The viscosity was measured using a fully automatic viscosity measuring device (model DT553, capillary type) manufactured by Sentec Co., Ltd. in the following manner. That is, a mixed solution of PTM11 (a 1 / 1 mass ratio mixture of phenol and 1,1,2,2-tetrachloroethane) was used as the solvent, and the number of seconds it took for a sample 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. Intrinsic viscosity (dL / g)=((1+4K H η sp ) 0.5 -1) / (2K H C) (However, η sp =η / η0-1, where η is the time it takes for the sample solution to fall, η0 is the time it takes for the solvent to fall, C is the concentration of the sample solution (g / dL), and K H is Huggins' constant. K H The value used was 0.33.)

[0096] <Tensile modulus and elongation at break of polyether polyol copolymer polyester> A 1 mm thick resin sheet was prepared using a heat press, and this was cut into a No. 5 dumbbell-shaped test piece in accordance with JIS K 6251. A tensile test was carried out using a tensile testing machine (Shimadzu Corporation, product name "AGS-X") with a chuck distance of 40 mm, a tensile speed of 10 mm / min, a temperature of 23°C, and a relative humidity of 60%, to measure the stress and strain during deformation. The tensile modulus and tensile elongation at break were calculated from these measurement results.

[0097] [Synthesis example of polyether polyol containing oxymethylene groups] The synthesis examples of the polyether polyols containing oxymethylene groups used in the examples and comparative examples are shown below. The proportion of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group of the oxymethylene group-containing polyether polyols synthesized in the following synthesis examples: [POM] x 100 / [POM-PTMG] and the number average molecular weight were determined by the following methods.

[0098] <[POM] x 100 / [POM-PTMG]> 50 mg of polyether polyol was dissolved in 0.75 mL of CDCl3 and heated at 400 MHz. 1 H-NMR (ECZ-400S, manufactured by JEOL Ltd.) was measured. The sum of the integrals of the singlet peaks observed between 4.5 ppm and 4.8 ppm (hereinafter referred to as "A") and the integral of the peak observed at the highest magnetic field among the singlet peaks observed between 4.5 ppm and 4.8 ppm (hereinafter referred to as "B") were measured, and (AB) / A was calculated. (AB) / A was defined as the ratio of methyleneoxy repeating units in the polymethyleneoxypolyalkyleneoxy group: [POM] / [POM-PTMG], and this value was multiplied by 100 to obtain the value [POM] x 100 / [POM-PTMG].

[0099] <Number average molecular weight> The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polyether polyol were measured using a GPC (gel permeation chromatography) measuring device (HLC-8220GPC, manufactured by Tosoh Corporation) with chloroform as an eluent and polystyrene as a standard sample, and the molecular weight distribution was calculated.

[0100] <Synthesis Example 1> A 500 mL three-necked glass flask equipped with a magnetic stirrer and a Dean-Stark trap was charged with 300 g of PTMG1000, 20 g of paraformaldehyde (PFA), 0.4 mL of TfOH (10% aqueous solution), and 140 mL of toluene, and the atmosphere was purged with nitrogen gas. The separable flask was heated in a 120 °C oil bath, and the reaction was carried out at atmospheric pressure for 4 hours while removing water under reflux conditions. The internal temperature was then cooled to 50 °C, the pressure was reduced to 11 mmHg, and the toluene was removed from the system. The pressure was then reduced to 8 mmHg, and the reaction was carried out for 3 hours at a maximum temperature of 150 °C. The internal temperature was then cooled to 100°C, and 7 g of hydrotalcite was added to the reaction solution to deactivate the TfOH catalyst. The hydrotalcite was then removed by pressure filtration using a PTFE membrane filter, yielding a polyether polyol containing oxymethylene groups. The polyether polyol containing oxymethylene groups produced in Synthesis Example 1 is referred to as "POM-PTMG1." This POM-PTMG1 had a [POM]×100 / [POM-PTMG] of 6.72 mol % and a number average molecular weight of 2,000.

[0101] <Synthesis Example 2> A polyether polyol containing polymethyleneoxypolyalkyleneoxy groups was obtained in the same manner as in Synthesis Example 1, except that 300 g of PTMG650 was used instead of 300 g of PTMG1000 and the amount of PFA was changed to 30 g. The polyether polyol containing oxymethylene groups produced in Synthesis Example 2 is referred to as "POM-PTMG2." This POM-PTMG2 had a [POM]×100 / [POM-PTMG] of 10.7 mol % and a number average molecular weight of 2,000.

[0102] <Synthesis Example 3> A polyether polyol containing polymethyleneoxypolyalkyleneoxy groups was obtained in the same manner as in Synthesis Example 1, except that 300 g of PTMG250 was used instead of 300 g of PTMG1000 and the amount of PFA was changed to 80 g. The polyether polyol containing oxymethylene groups produced in Synthesis Example 2 is referred to as "POM-PTMG3." This POM-PTMG3 had a [POM]×100 / [POM-PTMG] of 22.4 mol % and a number average molecular weight of 2,000.

[0103] <Synthesis Example 4> A polyether polyol containing polymethyleneoxypolyalkyleneoxy groups was obtained in the same manner as in Synthesis Example 1, except that 300 g of BG was used instead of 300 g of PTMG1000 and the amount of PFA was changed to 230 g. The polyether polyol containing oxymethylene groups produced in Synthesis Example 4 is referred to as "POM-PTMG4." This POM-PTMG4 had a [POM]×100 / [POM-PTMG] of 50.0 mol % and a number average molecular weight of 2,000.

[0104] [Example 1] A transesterification reaction vessel equipped with a stirrer, nitrogen inlet, heater, thermometer, and distillation tube was charged with 71.3 parts by mass of DMT, 38.6 parts by mass of BG, 20.0 parts by mass of POM-PTMG1 (2.72 mol% relative to the total diol components), and tetrabutyl titanate as a catalyst, converted to titanium metal. The resulting polymer (POM-PTMG copolymerized PBT) was added as a BG solution to a concentration of 61 ppm by mass. The liquid temperature in the vessel was then maintained at 150 ° C. for 60 minutes, after which it was heated to 210 ° C. over 105 minutes and held at 210 ° C. for 15 minutes. During this time, the resulting methanol was distilled off, and the transesterification reaction was carried out for a total of 180 minutes.

[0105] After completion of the transesterification reaction, a solution of BG was added in an amount that would result in 33 mass ppm of titanium metal relative to the polymer producing tetrabutyl titanate, and the mixture was then transferred to a polycondensation reaction vessel equipped with a stirrer, a nitrogen inlet, a heater, a thermometer, a distillation tube, and a pressure-reducing exhaust port, and the polycondensation reaction was carried out under reduced pressure. The polycondensation reaction was carried out by gradually reducing the pressure inside the vessel from normal pressure to 0.4 kPa over 85 minutes and then maintaining the reaction temperature 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 time required for the polycondensation reaction was 210 minutes (the polycondensation reaction time was defined as the time from the start of pressure reduction to the time the pressure was restored with nitrogen).

[0106] The vessel was then restored to a reduced pressure with nitrogen and then pressurized to withdraw the polymer. The temperature of the heat transfer medium in the die during withdrawal 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 to obtain the polymethyleneoxypolyalkylene copolymer polyester (POM-PTMG1 copolymer PBT) of the present invention. The evaluation results of the obtained POM-PTMG1 copolymer PBT are shown in Table 1.

[0107] For this POM-PTMG1 copolymer PBT, the content of oxymethylene units in all diol components calculated from the charged amounts [POM] × 100 / [(POM-PTMG) + BG] was 0.183 mol% (= 6.72 mol% × 2.72 mol%).

[0108] [Example 2] A POM-PTMG2 copolymer PBT was obtained in the same manner as in Example 1, except that POM-PTMG1 was changed to POM-PTMG2 in Example 1. The evaluation results of the obtained POM-PTMG2 copolymer PBT are shown in Table 1.

[0109] [Example 3] A POM-PTMG3 copolymer PBT was obtained in the same manner as in Example 1, except that POM-PTMG1 was changed to POM-PTMG3. The evaluation results of the obtained POM-PTMG3 copolymer PBT are shown in Table 1.

[0110] [Comparative Example 1] A POM-PTMG4 copolymer PBT was obtained in the same manner as in Example 3, except that POM-PTMG3 in Example 3 was changed to POM-PTMG4 and the amount of POM-PTMG4 used was adjusted so that the content of oxymethylene units relative to all diol components in the resulting polyester ([POM] × 100 / [(POM-PTMG) + BG]) (mol %) was the same as in Example 3. The evaluation results of the resulting POM-PTMG4 copolymer PBT are shown in Table 1.

[0111] Comparative Example 2 A PTMG2000 copolymerized PBT was obtained in the same manner as in Example 1, except that POM-PTMG1 was changed to PTMG2000. The evaluation results of the obtained PTMG2000 copolymerized PBT are shown in Table 1.

[0112] [Table 1]

[0113] [Evaluation of results] As is clear from the above Examples 1 to 3 and Comparative Examples 1 and 2, high flexibility can be imparted by increasing the content of methyleneoxy (—CH2—O—) repeating units in the polymethyleneoxypolyalkyleneoxy group to more than 0 mol% according to the present invention. Furthermore, by setting the content to less than 50 mol%, thermal decomposition of the polymethyleneoxypolyalkylene component during the transesterification reaction or esterification reaction and polycondensation reaction can be suppressed, thereby increasing the degree of polymerization (intrinsic viscosity), and thereby imparting high tensile resistance to break. Therefore, it is clear that the polyester of the present invention can be suitably used in applications where the above physical properties are required.

Claims

1. Methyleneoxy (-CH ２ A polyester having a polymethyleneoxypolyalkyleneoxy group in which the content of repeating units of the formula (—O—) is more than 0 mol % and less than 50 mol %.

2. The polyester according to claim 1 , wherein the polymethyleneoxypolyalkyleneoxy group is represented by the following formula (1): 【Chemical 1】 (In the formula, R is a divalent hydrocarbon group having two or more carbon atoms. n, m, and s are each independently an integer of 1 or more.)

3. The methyleneoxy (—CH ２ 2. The polyester according to claim 1, wherein the content of repeating units of the formula (—O—) is less than 30 mol %.

4. 2. The polyester according to claim 1, wherein the content of a diol component having a hydroxyl group bonded to a carbon atom-side end of the polymethyleneoxypolyalkyleneoxy group and a hydrogen atom bonded to an oxygen atom-side end of the polymethyleneoxypolyalkyleneoxy group is less than 5 mol % of all diol components constituting the polyester.

5. 2. The polyester according to claim 1, wherein the number average molecular weight of the polymethyleneoxypolyalkyleneoxy groups is greater than 1,000 and less than 3,000.

6. 3. The polyester according to claim 2, wherein R in formula (1) is an n-butylene group.

7. The polyester according to claim 1 , wherein the dicarboxylic acid component constituting the polyester comprises a terephthalic acid component.

8. 2. The polyester according to claim 1, wherein the diol component constituting the polyester comprises a diol having a hydroxyl group bonded to a carbon atom-side end of a polymethyleneoxypolyalkyleneoxy group and a hydrogen atom bonded to an oxygen atom-side end thereof, and 1,4-butanediol.

9. A method for producing a polyester according to any one of claims 1 to 8, comprising charging a diol having a hydroxyl group bonded to the carbon atom-side end of a polymethyleneoxypolyalkyleneoxy group and a hydrogen atom bonded to the oxygen atom-side end thereof, a diol other than said diol, and a dicarboxylic acid and / or an ester-forming derivative thereof into a reaction vessel, and carrying out a transesterification reaction and / or an esterification reaction and a polycondensation reaction to produce the polyester according to any one of claims 1 to 8.

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