JP2011148941A - Aromatic polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aromatic polyester excellent in heat resistance and rigidity, and having a suitable crystallization speed. <P>SOLUTION: The aromatic polyester includes a 2,6-naphthalene dicarboxylic acid residue and a bishydroxyalkoxybiphenyl residue, or a 2,6-naphthalene dicarboxylic acid residue, an aliphatic diol residue and a bishydroxyalkoxybiphenyl residue, and has a high heat resistance and a crystallization speed suitable for spinning, film formation and molding. There is also provided a method for manufacturing the same. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention comprises a 2,6-naphthalenedicarboxylic acid residue and a bishydroxyalkoxy aromatic residue, or a 2,6-naphthalenedicarboxylic acid residue, an aliphatic diol residue, and a bishydroxyalkoxy aromatic residue. In addition, the present invention relates to an aromatic polyester having high heat resistance and rigidity and having a crystallization speed suitable for spinning, film formation and molding, and a method for producing the same.

  An aromatic polyester composed of an aromatic dicarboxylic acid represented by polyethylene terephthalate (hereinafter sometimes abbreviated as PET) and polyethylene-2,6-naphthalate (hereinafter sometimes abbreviated as PEN) and a glycol component is Since it has excellent mechanical properties and chemical properties, it is widely used in molded products such as fibers, films, and bottles. However, there is a strong demand for higher performance from the market, and improvements are desired.

  In particular, if there is an aromatic polyester having the same high heat resistance and high rigidity as PEN and the same crystallization speed as PET, it is extremely useful for various applications such as fibers, films and molded articles. However, despite the fact that many aromatic polyesters have been reported (for example, Patent Documents 1 to 4), aromatic polyesters that satisfy all of the above required properties have not been obtained.

JP-A-4-59822 (US Pat. No. 5,182,359) JP-A-10-204166 JP 11-292959 A Japanese Patent Laid-Open No. 10-101782

  An object of the present invention is to provide an aromatic polyester which is excellent in heat resistance and rigidity and has an appropriate crystallization rate.

  In view of the above problems, the present inventors have outstanding physical properties of aromatic polyesters that contain 2,6-naphthalenedicarboxylic acid residues as dicarboxylic acid residues and bishydroxyalkoxybiphenyl residues as diol residues. As a result, the present invention has been completed. The gist of the present invention is shown below.

にて表される２，６−ナフタレンジカルボン酸残基であり、ジオール残基のうち８０モル%以上が下記一般式（２）

（上記一般式（２）において、ｍ_１及びｍ_２はそれぞれ独立には２または３である。）
にて表されるビスヒドロキシアルコキシビフェニル残基であり、ｐ−クロロフェノール／１，１，２，２−テトラクロロエタン（質量比４０／６０）の混合溶媒を用いて（試料濃度１．２ｇ／ｄＬ）３５℃で測定した還元粘度が０．３〜３．０ｄL／ｇであることを特徴とする芳香族ポリエステル。
２． 芳香族ポリエステルを構成するジオール残基のうち１５モル%以下が、下記一般式（３）

（上記一般式（３）において、ｎは２又は４である。）
にて表される脂肪族ジオール残基である上記１項記載の芳香族ポリエステル。
３． 芳香族ポリエステルを構成するジオール残基において、上記一般式（２）にて表されるビスヒドロキシアルコキシビフェニル残基と、上記一般式（３）にて表される脂肪族ジオール残基とのモル比が９５：５以上１００：０未満である上記２項記載の芳香族ポリエステル。
４． 示差走査熱量計（ＤＳＣ）にて観測されるガラス転移温度（Ｔ_ｇ）が７５〜１３０℃、結晶融点（Ｔ_ｍ）が２２０〜２８０℃である上記１〜３項の何れか１つに記載の芳香族ポリエステル。
５． 示差走査熱量計（ＤＳＣ）にて観測される結晶融解エンタルピー（ΔＨ_ｍ）が２０〜７０Ｊ／ｇである上記１〜４項の何れか１つに記載の芳香族ポリエステル。
６． 示差走査熱量計（ＤＳＣ）にて観測される降温結晶化温度（Ｔ_ｃｄ）と同温度において測定される半結晶化時間ｔ_１／２が１〜１２０秒である上記１〜５項の何れか１つに記載の芳香族ポリエステル。
７． 上記一般式（２）において、ｍ_１及びｍ_２が共に２である上記１〜６項の何れか１項に記載の芳香族ポリエステル。
８． 上記一般式（３）において、ｎが２である上記２〜７項の何れか１つに記載の芳香族ポリエステル。
９． 下記一般式（４）

（上記一般式（４）中において、ｍ_１及びｍ_２はそれぞれ独立には２又は３である。）
で表されるビスヒドロキシアルコキシビフェニルと下記一般式（５）

（上記一般式（５）において、Ｒは、炭素数１〜４のアルキル基、水素原子、又は塩素原子を表す。）
で表される２，６−ナフタレンジカルボン酸類とを重縮合反応させることを特徴とする、上記１項記載の芳香族ポリエステルの製造方法。
１０． 上記９項記載の一般式（４）で表されるビスヒドロキシアルコキシビフェニルと、上記９項記載の一般式（５）で表される２，６−ナフタレンジカルボン酸類と、下記一般式（６）

（上記一般式（６）において、ｎは２又は４である。）
で表される脂肪族ジオールとを重縮合反応させることを特徴とする、上記２項記載の芳香族ポリエステルの製造方法。 1. Of the dicarboxylic acid residues constituting the aromatic polyester, 50 mol% or more is represented by the following general formula (1):

2,6-naphthalenedicarboxylic acid residue represented by the formula, 80 mol% or more of the diol residue is represented by the following general formula (2)

(In the general formula (2), m ₁ and m ₂ are each independently 2 or 3.)
Using a mixed solvent of p-chlorophenol / 1,1,2,2-tetrachloroethane (mass ratio 40/60) (sample concentration 1.2 g / dL) An aromatic polyester having a reduced viscosity measured at 35 ° C. of 0.3 to 3.0 dL / g.
2. 15 mol% or less of the diol residues constituting the aromatic polyester is represented by the following general formula (3)

(In the general formula (3), n is 2 or 4.)
2. The aromatic polyester according to 1 above, which is an aliphatic diol residue represented by:
3. In the diol residue constituting the aromatic polyester, the molar ratio between the bishydroxyalkoxybiphenyl residue represented by the general formula (2) and the aliphatic diol residue represented by the general formula (3) 3. The aromatic polyester according to the above item 2, wherein is 95: 5 or more and less than 100: 0.
4). 4. The glass transition temperature (T _g ) observed by a differential scanning calorimeter (DSC) is 75 to 130 ° C., and the crystal melting point (T _m ) is 220 to 280 ° C. Aromatic polyester.
5. The aromatic polyester as described in any one of 1 to 4 above, wherein the crystal melting enthalpy (ΔH _m ) observed by a differential scanning calorimeter (DSC) is 20 to 70 J / g.
6). Any one of 1 to 5 above, wherein the half crystallization time t _1/2 measured at the same temperature as the temperature-falling crystallization temperature (T _cd ) observed with a differential scanning calorimeter (DSC) is ₁ to 120 seconds. The aromatic polyester according to one.
7). The aromatic polyester according to any one of 1 to 6 above, wherein in the general formula (2), m ₁ and m ₂ are both 2.
8). The aromatic polyester according to any one of 2 to 7 above, wherein in the general formula (3), n is 2.
9. The following general formula (4)

(In the general formula (4), m ₁ and m ₂ are each independently 2 or 3.)
And bishydroxyalkoxybiphenyl represented by the following general formula (5)

(In the general formula (5), R represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, or a chlorine atom.)
2. The method for producing an aromatic polyester according to the above item 1, wherein the polycondensation reaction is performed with 2,6-naphthalenedicarboxylic acid represented by formula (1).
10. Bishydroxyalkoxybiphenyl represented by the general formula (4) described in 9 above, 2,6-naphthalenedicarboxylic acids represented by the general formula (5) described in 9 above, and the following general formula (6)

(In the general formula (6), n is 2 or 4.)
The method for producing an aromatic polyester according to the above item 2, wherein the polycondensation reaction is carried out with an aliphatic diol represented by the formula:

  ADVANTAGE OF THE INVENTION According to this invention, the aromatic polyester which is excellent in heat resistance and rigidity which was not able to have with conventional aromatic polyesters, such as PET and PEN, and has an appropriate crystallization rate can be obtained.

  In the aromatic polyester of the present invention, 50 mol% or more of the dicarboxylic acid residues constituting the aromatic polyester is a 2,6-naphthalenedicarboxylic acid residue represented by the general formula (1), and a diol 80 mol% or more of the residues are bishydroxyalkoxybiphenyl residues represented by the general formula (2), and p-chlorophenol / 1,1,2,2-tetrachloroethane (mass ratio 40/60). The reduced viscosity measured at 35 ° C. using a mixed solvent (sample concentration 1.2 g / dL) is 0.3 to 3.0 dL / g. The reduced viscosity of the aromatic polyester of the present invention is preferably 0.4 to 2.0 dL / g, more preferably 0.7 to 1.5 dL / g, and 0.9 to 1.3 dL / g. And even more preferable.

  In the aromatic polyester of the present invention, the 2,6-naphthalenedicarboxylic acid residue represented by the general formula (1) is preferably 70 mol% or more of the dicarboxylic acid residue constituting the aromatic polyester. 80 mol% or more, more preferably 90 mol% or more, and even more preferably 90 mol% or more, and particularly preferably 100 mol%, that is, those which do not intentionally copolymerize other dicarboxylic acid components. In addition, the aromatic dicarboxylic acid residue in which the ratio of the 2,6-naphthalenedicarboxylic acid residue represented by the general formula (1) is less than 50 mol%, and the general formula (2) An aromatic polyester composed of a bishydroxyalkoxybiphenyl residue has insufficient heat resistance and rigidity.

  As long as the aromatic polyester of this invention is less than 50 mol% among the dicarboxylic acid residues which comprise this aromatic polyester, what contains another repeating unit, ie, a copolymer, may be sufficient. Examples of the copolymerized dicarboxylic acid residue constituting such other repeating unit include terephthalic acid, isophthalic acid, phthalic acid, diphenyldicarboxylic acid, 1,5-, 1,6-, 1,7-, or 2, 7-naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, benzophenone dicarboxylic acid, phenylindanedicarboxylic acid, 5-sulfoxyisophthalic acid metal salt, 5-sulfoxyisophthalic acid phosphonium salt, 2,5-furandicarboxylic acid, etc. And residues derived from one or more dicarboxylic acids selected from the group consisting of aliphatic dicarboxylic acids such as aromatic dicarboxylic acids, oxalic acid, succinic acid, adipic acid, sebacic acid, cyclohexanedicarboxylic acid and the like.

  In the aromatic polyester of the present invention, the bishydroxyalkoxybiphenyl residue represented by the general formula (2) among the diol residues constituting the aromatic polyester is preferably 85 mol% or more, and 90 mol%. More preferably, it is more preferably 95 mol% or more. A diol residue in which the ratio of the bishydroxyalkoxybiphenyl residue represented by the general formula (2) is less than 80 mol%, and 2,6-naphthalenedicarbon represented by the general formula (1) Aromatic polyesters composed of acid residues are insufficient in heat resistance and rigidity.

  The aromatic polyester of the present invention may be a copolymer containing other repeating units as long as it is 20 mol% or less of the diol residues constituting the aromatic polyester. Examples of copolymer diol residues constituting such other repeating units include 1,4-bis (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxypropoxy) benzene, and 1,4-bis. (2-hydroxyethoxyethoxy) benzene, 1,4-bis (2-hydroxypropoxycypropoxy) benzene, 4,4'-bis (2-hydroxyethoxyethoxy) biphenyl, 4,4'-bis (2-hydroxypropoxy) Propoxy) biphenyl, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, 2,2-bis [4- (2-hydroxyethoxyethoxy) phenyl] propane, 1,3-bis (2-hydroxy) Ethoxy) benzene, 1,3-bis (2-hydroxyethoxyethoxy) benzene, 1,2-bis (2-hydroxy) Loxyethoxy) benzene, 1,2-bis (2-hydroxyethoxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) diphenylsulfone, 4,4′-bis (2-hydroxyethoxyethoxy) diphenylsulfone, Glycol adduct diphenols such as 9,9-bis- (4- (2-hydroxyethoxy) phenyl) fluorene, ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, deca Methylene glycol, neopentylene glycol, diethylene glycol, polyethylene glycol, cyclohexanediol, cyclohexanedimethanol, pentacyclopentadecanedimethanol, 1,3-adamanta Aliphatic glycols such as dimethanol, isosorbide, isomannide, isoidide, 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane, etc. Cyclic ether skeleton diol, aromatic glycol such as o, m, p-xylylene glycol, hydroquinone, 2,2-bis (4-hydroxyphenyl) propane, resorcin, catechol, dihydroxynaphthalene, dihydroxybiphenyl, dihydroxydiphenylsulfone, Examples thereof include residues derived from one or more diols selected from the group consisting of diphenols such as 9,9-biscresol fluorene. Among these, it is derived from one or more aliphatic diols selected from the group consisting of the residue represented by the general formula (3), that is, ethylene glycol and tetramethylene glycol (1,4-butanediol). Residue is preferred, and the proportion of the residue in the diol residue is preferably 15 mol% or less and more than 0%, preferably 5 mol% or less and more than 0%, that is, in the diol residue constituting the aromatic polyester, The molar ratio of the bishydroxyalkoxybiphenyl residue represented by the general formula (2) and the aliphatic diol residue represented by the general formula (3) is 95: 5 or more and less than 100: 0. More preferred. It is preferable that the diol residue has the above composition because the balance between heat resistance and moldability is particularly good.

The aromatic polyester of the present invention preferably has a glass transition temperature (T _g ) observed by DSC of 75 ° C. to 130 ° C. and a crystalline melting point (T _m ) of 220 ° C. to 280 ° C. T _g and T _m is the case of less than the above range may be insufficient heat resistance of the aromatic polyester, very high processing temperatures required for injection molding or melt film is if it exceeds the above range to the contrary Therefore, there is a risk of causing thermal decomposition and coloring of the aromatic polyester. The aromatic polyester of the present invention preferably has a glass transition temperature (T _g ) of 100 ° C. to 125 ° C. and a crystal melting point (T _m ) of 240 ° C. to 260 ° C.

The aromatic polyester of the present invention preferably has a crystal melting enthalpy ΔH _m observed by DSC of 20 to 70 J / g, particularly preferably 40 to 60 J / g. When ΔH _m is less than 20 J / g, there is a concern that the crystallinity is insufficient or the rigidity is lowered. On the other hand, if it exceeds 70 J / g, the aromatic polyester may become brittle. Further, the aromatic polyester of the present invention has a half crystallization time t _1/2 measured at the same temperature as the temperature-falling crystallization temperature (T _cd ) observed with a differential scanning calorimeter (DSC) of 1 second to 120 seconds. Preferably, it is 10 seconds to 100 seconds, more preferably 30 to 80 seconds. When the half crystallization time t1 _{/ 2} is less than 1 second, there is a possibility that substantial fluidity cannot be secured in injection molding or melt film formation. On the other hand, if it exceeds 120 seconds, the injection molding cycle is prolonged, and in melt film formation, it may take a long time for heat setting, which is not preferable. The semi-crystallization time referred to here is a temperature-down crystallization temperature T _cd of a sample placed between orthogonal polarizing plates using a polymer crystallization rate measuring device (manufactured by Kotaki Seisakusho Co., Ltd., model MK-801). It is the time when the crystallized degree becomes 0.5 by using the Arami equation after measuring the transmitted light due to the increasing optical anisotropic crystal component at each sample temperature (depolarization intensity method).

In the aromatic polyester of the present invention, m ₁ and m ₂ are both 2 in the repeating unit represented by the general formula (2), that is, the bishydroxyalkoxybiphenyl residue is 4,4′-bis (2-hydroxyethoxy). A biphenyl residue is preferred.
The aliphatic diol residue represented by the general formula (3) is preferably a residue where n = 2 in the general formula (3), that is, an ethylene glycol residue.

  The aromatic polyester of the present invention may be used alone, or other thermoplastic polymer (for example, polyalkylene terephthalate, polyarylate, liquid crystalline polyester, polyamide, polyimide, polyetherimide as long as the object of the present invention is not impaired). , Polyurethane, silicone, polyphenylene ether, polyphenylene sulfide, polysulfone, polyolefins such as polyethylene and polypropylene), fillers (glass fiber, carbon fiber, natural fiber, organic fiber, ceramic fiber, ceramic beads, talc, clay, mica, etc.) , Natural polymers (polyhydroxybutyrate (PHB), polyhydroxybutyrate / valerate, polyhydroxyvalylate / hexanoate, polycaprolactone (PCL), polybutyrate Aliphatic polyesters such as succinate (PBS), polybutylene succinate / adipate, polyethylene succinate, polylactic acid resin, polymalic acid, polyglycolic acid, polydioxanone, poly (2-oxetanone); polybutylene succinate / terephthalate, polybutylene Aliphatic aromatic copolyesters such as adipate / terephthalate, polytetramethylene adipate / terephthalate; starch, cellulose, chitin, chitosan, gluten, gelatin, zein, soy protein, collagen, keratin), antioxidants (hindered phenol compounds) , Sulfur antioxidants, etc.), flame retardant additives (phosphorus, bromo, etc.), UV absorbers (benzotriazole, benzophenone, cyanoacrylate, etc.), flow modifiers, wearing Agent, light diffusion agent, infrared absorber, organic pigments, inorganic pigments, release agent, may be obtained by adding a plasticizer.

<Manufacturing method>
Next, the method for producing the aromatic polyester of the present invention will be described in detail.
As a method for producing the aromatic polyester of the present invention, the bishydroxyalkoxybiphenyl represented by the general formula (4) as a raw material diol is represented by the general formula (5) as a raw material aromatic dicarboxylic acid. A preferable production method is a polycondensation reaction using 2,6-naphthalenedicarboxylic acids. At this time, a diol other than the above bishydroxyalkoxybiphenyl or a dicarboxylic acid other than the 2,6-naphthalenedicarboxylic acid may be used as the aromatic polyester of the copolymer. 50 mol% or more of the dicarboxylic acid residues to be represented are represented by the above general formula (2), and 2,6-naphthalenedicarboxylic acid residues represented by the general formula (1) and 80 mol% or more of the diol residues are represented by the general formula (2). The raw material charge composition in the polycondensation reaction is also set so that the bishydroxyalkoxybiphenyl residue represented by Specifically, first, polycondensation is performed by matching the target copolymer composition (molar ratio) with the charge of the corresponding raw material, and the reactivity and volatility (scattering during polycondensation reaction) for each raw material component. If the charge ratio and the copolymerization composition of the produced aromatic polyester appear to be different due to, for example, different easiness), the amount of each raw material component may be adjusted by increasing / decreasing in the subsequent raw material charging.

  The dicarboxylic acids that can be used to obtain the aromatic polyester of the above copolymer include aromatic dicarboxylic acids such as terephthalic acid exemplified for the copolymerized dicarboxylic acid residue, and aliphatic dicarboxylic acids such as oxalic acid. One or more types selected from the group can be mentioned. Examples of the diols that can be used to obtain the aromatic polyester of the above copolymer include glycol adduct-type diesters such as 1,4-bis (2-hydroxyethoxyethoxy) benzene described above as the copolymer diol residue. One or more selected from the group consisting of phenols, aliphatic glycols such as ethylene glycol, cyclic ether skeleton diols such as isosorbide, aromatic glycols such as o, m, p-xylylene glycol, and diphenols such as hydroquinone In particular, one or more aliphatic diols selected from the group consisting of aliphatic diols represented by the general formula (6), that is, ethylene glycol and tetramethylene glycol (1,4-butanediol). In that case, in the aromatic polyester as described above Preparation of raw materials in the polycondensation reaction so that the proportion of the residue represented by the general formula (3) in the diol residue is 15 mol% or less and more than 0%, preferably 5 mol% or less and more than 0%. It is preferable to set the composition.

  As a method of polycondensing the bishydroxyalkoxybiphenyl represented by the general formula (4) and the 2,6-naphthalenedicarboxylic acid represented by the general formula (5) as an aromatic dicarboxylic acid as a raw material, A known polycondensation method of polyester, that is, a direct polymerization method in which 2,6-naphthalenedicarboxylic acid and the bishydroxyalkoxybiphenyl are esterified to obtain an oligomer, which is further subjected to melt polycondensation at high temperature under reduced pressure, 2 , 6-Naphthalenedicarboxylic acid alkyl ester having 1 to 4 carbon atoms and the bishydroxyalkoxybiphenyl are transesterified in the presence of a metal compound as a catalyst to obtain an oligomer, which is further melted at high temperature under reduced pressure. Transesterification method for condensation reaction, 2,6-naphthalenedicarboxylic acid chloride and the bishydroxyl Although such a polycondensation process of reacting an alkoxy biphenyl in the presence of a base such as pyridine and the like, preferably a direct polymerization method or an ester exchange method, in particular an ester exchange method is preferred.

  In the direct polymerization method, esterification of 2,6-naphthalenedicarboxylic acid and the bishydroxyalkoxy aromatic compound is usually performed by dehydrating condensation of these raw material compounds at a temperature of 180 to 260 ° C. under normal pressure or pressure. Can be performed. This dehydration condensation reaction, that is, esterification proceeds without the addition of a catalyst due to the acidity of 2,6-naphthalenedicarboxylic acid itself, but even if a catalyst such as a titanium compound or a tin compound is added to accelerate the reaction. Good.

  Transesterification of the alkyl ester of C1-C4 of 2,6-naphthalenedicarboxylic acid and the bishydroxyalkoxy aromatic compound in the above transesterification method, usually at a temperature of 180-260 ° C., a titanium compound, manganese acetate In the presence of a transesterification catalyst such as magnesium acetate, the lower alcohol produced as a by-product can be distilled off. The alkyl ester having 1 to 4 carbon atoms of 2,6-naphthalenedicarboxylic acid used in the production method of the present invention is preferably a methyl ester, that is, dimethyl 2,6-naphthalenedicarboxylate.

  In the above transesterification method, the charged molar ratio of the alkyl ester having 1 to 4 carbon atoms of 2,6-naphthalenedicarboxylic acid and the bishydroxyalkoxybiphenyl represented by the general formula (4) is high molecular weight. In order to obtain an aromatic polyester, the ratio is preferably 1: 1, but it is anticipated that the alkyl ester having 1 to 4 carbon atoms of 2,6-naphthalenedicarboxylic acid will sublimate and be removed from the system under heating conditions. A method in which the alkyl ester having 1 to 4 carbon atoms of 2,6-naphthalenedicarboxylic acid is charged slightly excessively as in 1.1: 1 to 1.01: 1 is also a preferable mode. In addition, when using a copolymerization component, it is preferable when the total amount of a dicarboxylic acid component and the sum total of a diol component become the said molar ratio.

About the reaction temperature of said transesterification method, the method of heating up in steps according to progress of transesterification reaction is also a preferable form. The aromatic polyester of the present invention can be obtained by heating the oligomer thus obtained to advance the melt polycondensation reaction. The temperature of the melt polycondensation reaction is preferably in the range of at least the melting point of the aromatic polyester to be obtained and the melting point + 50 ° C., more preferably in the range of the melting point plus 10 ° C. to the melting point + 30 ° C. In the melt polycondensation reaction, it is usually preferable to carry out under a reduced pressure of 6.7 × 10 ⁻⁴ MPa or less. If it is higher than 6.7 × 10 ⁻⁴ MPa, the time required for the polycondensation reaction becomes long and it becomes difficult to obtain an aromatic polyester resin having a high degree of polymerization. In particular, the pressure is preferably reduced to 1.3 × 10 ⁻⁴ MPa or less. It is also preferable to reduce the pressure stepwise in order to prevent rapid progress of reaction and bumping of reactants.

  The metal compound catalyst used in the transesterification method is at least one selected from the group consisting of titanium, germanium, antimony, aluminum, nickel, zinc, tin, cobalt, rhodium, iridium, zirconium, hafnium, lithium, calcium, magnesium and the like. A metal compound containing a metal element is exemplified, and a metal compound such as titanium, germanium, antimony, aluminum, and tin is more preferable. In particular, a titanium compound is preferable because it exhibits high activity. The amount of the metal compound catalyst used is preferably 0.005 to 0.5 mol%, more preferably 0.01 to 0.1 mol%, based on the number of moles of the repeating unit of the aromatic polyester.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Measurement of reduced viscosity (η _{sp / C} )]
The reduced viscosity (η _{sp / C} ) of the aromatic polyester was obtained by dissolving 0.12 g of a sample piece in 10 mL of a mixed solvent of p-chlorophenol / 1,1,2,2-tetrachloroethane (mass ratio 40/60) ( The sample concentration was 1.2 g / dL) and measured at 35 ° C.

[Differential scanning calorimeter (DSC) measurement]
DSC measurement was performed using a differential scanning calorimeter (DSC2920) manufactured by TA Instruments, with about 7 mg of an aromatic polyester sample piece placed in a dedicated aluminum pan. Measurement is performed by raising the temperature from 30 ° C. to 300 ° C. at 10 ° C./min, and then cooling from 300 ° C. to 30 ° C. at 10 ° C./min, and the obtained chart is subjected to glass transition according to JIS standard K7121. The temperature (T _g ), crystal melting point (T _m ), melting enthalpy (ΔH _m ), temperature rising crystallization temperature (T _ci ), and temperature falling crystallization temperature (T _cd ) were determined.

[Semi-crystallization time t _1/2 in T _cd ]
Half-crystallization time at T _cd is a polymer crystallization rate measuring apparatus (Kotaki Seisakusho Co., Ltd., MK-801 type) _was used to measure at _{T cd} and the same temperature. Immediately after melting the sample sandwiched between the glass covers for the microscope, it is immediately set in the middle of the orthogonal deflection plate in the sample chamber, and the crystallinity is 0.5 in the transmitted light abramie plot due to the increasing optical anisotropic crystal component. Was set as the half crystallization time t1 _{/ 2} .

[Measurement of copolymer composition (NMR analysis)]
The copolymer composition of the aromatic polyester was measured with a 400 MHz ¹ H-NMR apparatus (Hitachi Electronics, JEOL A-600) using a 90/10 (volume ratio) solution sample of deuterated chloroform / trifluoroacetic acid.

[Example 1]
244.2 parts by mass of dimethyl 2,6-naphthalenedicarboxylate and 274.3 parts by mass of 4,4′-bis (2-hydroxyethoxy) biphenyl were added to a mechanical stirring blade, a nitrogen introduction line, a reflux distillation line, a vacuum line, and a polymer. It was placed in a reaction vessel equipped with a discharge port, and nitrogen substitution was performed three times. Subsequently, the reaction vessel was heated to 230 ° C. to melt the raw materials. To this, 0.05 part by mass of titanium tetra-n-butoxide was added as a catalyst to initiate a transesterification reaction. After confirming that a predetermined amount of methanol had distilled off from the reflux distillation line, the reaction vessel was heated to 280 ° C., and the internal pressure of the vessel was reduced to 1.333 × 10 ⁻⁴ MPa. After melt polycondensation for 30 minutes under these conditions, the internal pressure was further reduced to 0.800 × 10 ⁻⁴ MPa to complete the melt polycondensation. After completion of the polymerization, the molten aromatic polyester was pressure-extruded from the polymer discharge port, and pelletized while cooling with water. Reduced viscosity (η _{sp / C} ) of the obtained aromatic polyester, glass transition temperature (T _g ) in DSC, crystal melting point (T _m ), melting enthalpy (ΔH _m ), elevated temperature crystallization temperature (T _ci ), Table 1 shows the temperature drop crystallization temperature (T _cd ) and the half crystallization time t _1/2 at the temperature drop crystallization temperature.

[Example 2]
The same procedures as in Example 1 were conducted except that the amount of 4,4′-bis (2-hydroxyethoxy) biphenyl was 260.6 parts by mass, and 3.1 parts by mass of ethylene glycol was also used as the starting diol. Various measurements were performed. The results are shown in Table 1. In addition, when the copolymerization composition of the diol residue in the obtained aromatic polyester was measured by NMR, the amount of ethylene glycol residues in all diol residues was 2.5 mol%.

[Example 3]
The same procedure as in Example 1 was carried out except that the amount of 4,4′-bis (2-hydroxyethoxy) biphenyl was 233.2 parts by mass, and 9.3 parts by mass of ethylene glycol was also used as the starting diol. Various measurements were performed. The results are shown in Table 1. In addition, when the copolymerization composition of the diol residue in the obtained aromatic polyester was measured by NMR, the amount of ethylene glycol residue in all diol residues was 13.4 mol%.

[Example 4]
The same procedures and various operations as in Example 1 except that 302.3 parts by mass of 4,4′-bis (3-hydroxypropoxy) biphenyl was used instead of 4,4′-bis (2-hydroxyethoxy) biphenyl. Measurements were made. The results are shown in Table 1.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that the amount of 4,4′-bis (2-hydroxyethoxy) biphenyl was 192.0 parts by mass, and 18.6 parts by mass of ethylene glycol was also used as the starting diol. Various measurements were performed. The results are shown in Table 1. In addition, when the copolymerization composition of the diol residue in the obtained aromatic polyester was measured by NMR, the amount of ethylene glycol residues in all diol residues was 25.6 mol%.

[Comparative Example 2]
Operation and various measurements were performed in the same manner as in Example 1 except that 198.2 parts by mass of 1,4-bis (2-hydroxyethoxy) benzene was used instead of 4,4′-bis (2-hydroxyethoxy) biphenyl. Went. The results are shown in Table 1.

The aromatic polyester of the present invention can be subjected to ordinary melt molding such as extrusion molding, injection molding, compression molding and blow molding, and can be processed into fibers, films, three-dimensional molded articles, containers and the like.

Claims (10)

Of the dicarboxylic acid residues constituting the aromatic polyester, 50 mol% or more is represented by the following general formula (1):

2,6-naphthalenedicarboxylic acid residue represented by the formula, 80 mol% or more of the diol residue is represented by the following general formula (2)

(In the general formula (2), m ₁ and m ₂ are each independently 2 or 3.)
Using a mixed solvent of p-chlorophenol / 1,1,2,2-tetrachloroethane (mass ratio 40/60) (sample concentration 1.2 g / dL) An aromatic polyester having a reduced viscosity measured at 35 ° C. of 0.3 to 3.0 dL / g. 15 mol% or less of the diol residues constituting the aromatic polyester is represented by the following general formula (3)

(In the general formula (3), n is 2 or 4.)
The aromatic polyester according to claim 1, which is an aliphatic diol residue represented by:   In the diol residue constituting the aromatic polyester, the molar ratio between the bishydroxyalkoxybiphenyl residue represented by the general formula (2) and the aliphatic diol residue represented by the general formula (3) The aromatic polyester according to claim 2, wherein the ratio is 95: 5 or more and less than 100: 0. Differential scanning calorimetry (DSC) glass transition temperature observed at _{(T g)} is seventy-five to one hundred thirty ° C., crystals the thermal melting point _{(T m)} is according to any one of claims 1 to 3 is 220 to 280 ° C. Aromatic polyester. The aromatic polyester according to any one of claims 1 to 4, wherein a crystal melting enthalpy (ΔH _m ) observed by a differential scanning calorimeter (DSC) is 20 to 70 J / g. Claim 1 half-crystallization time _{t 1/2} is 1 to 120 seconds as measured in the observed crystallization temperature _{(T cd)} at the same temperature by a differential scanning calorimeter (DSC) The aromatic polyester according to one. In the general formula (2), an aromatic polyester according to any one of claims 1 to 6 _{m 1} and _{m 2} are both 2.   In the said General formula (3), n is 2, The aromatic polyester as described in any one of Claims 2-7. The following general formula (4)

(In the general formula (4), m ₁ and m ₂ are each independently 2 or 3.)
And bishydroxyalkoxybiphenyl represented by the following general formula (5)

(In the general formula (5), R represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, or a chlorine atom.)
The method for producing an aromatic polyester according to claim 1, wherein a polycondensation reaction is performed with 2,6-naphthalenedicarboxylic acid represented by the formula: A bishydroxyalkoxybiphenyl represented by the general formula (4) according to claim 9, a 2,6-naphthalenedicarboxylic acid represented by the general formula (5) according to claim 9, and the following general formula (6)

(In the general formula (6), n is 2 or 4.)
The method for producing an aromatic polyester according to claim 2, wherein a polycondensation reaction is performed with an aliphatic diol represented by the formula: