KR20210150422A - Whole aromatic polyester and polyester resin composition - Google Patents

Abstract

[Problem] The present invention provides a wholly aromatic polyester in which the generation of sublimates during a polymerization reaction is reduced and foreign substances are reduced, and a polyester resin composition thereof.
[Solutions] As an essential component, it consists of the following structural units (I), (II), (III) and (IV), with respect to all the structural units, the content of the structural unit (I) is 40 to 75 mol% and, with respect to all the structural units, the content of the structural unit (II) is 0.5 to 7.5 mol%, with respect to all the structural units, the content of the structural unit (III) is 8.5 to 30 mol%, with respect to all the structural units, The content of the structural unit (IV) is 8.5 to 30 mol%, and the total content of the structural units (I), (II), (III) and (IV) is 100 mol% with respect to all the structural units. In the wholly aromatic polyester, the difference between the content of the structural unit (III) and the content of the structural unit (IV) is 0.150 mol% or less, the wholly aromatic polyester solves the above problems.
[Formula 1]

Description

Whole aromatic polyester and polyester resin composition

The present invention relates to a wholly aromatic polyester in which the generation of sublimates during a polymerization reaction is small and foreign substances are reduced, and a polyester resin composition thereof.

Liquid crystalline resins such as wholly aromatic polyesters have excellent fluidity, mechanical strength, heat resistance, chemical resistance, electrical properties and the like in a well-balanced manner, and therefore are preferably widely used as high-performance engineering plastics.

Most of the wholly aromatic polyesters currently on the market are based on 4-hydroxybenzoic acid. However, since the melting point of the homopolymer of 4-hydroxybenzoic acid becomes higher than the decomposition point, it is necessary to lower the melting point by copolymerizing various components.

Wholly aromatic polyester using 1,4-phenylenedicarboxylic acid, 1,4-dihydroxybenzene, 4,4'-dihydroxybiphenyl, etc. as a copolymerization component has a high melting point of 350°C or higher, so it can be melted in general-purpose equipment. Too high for processing. In addition, various methods have been attempted to lower the melting point of such a high melting point to a temperature that can be processed by a general-purpose melt processing machine. There is a problem that mechanical strength cannot be maintained.

In order to solve this problem, the wholly aromatic polyester which consists of a specific structure which has 6-hydroxy-2-naphthoic acid as a main component is proposed (patent document 1).

Japanese Patent Laid-Open No. 2002-179776

However, in the wholly aromatic polyester of Patent Document 1, a sublimate is generated during a polymerization reaction, and the sublimate is precipitated and deposited on the inner wall of a polymerization vessel, where polycondensation, deterioration, or carbonization is mixed into the polymer as a foreign material. there was a problem with

In addition, the sublimate generated during the polymerization reaction of the wholly aromatic polyester is a monomer component, which causes a disparity in terminal balance and becomes an obstacle to high molecular weight.

Therefore, this invention makes it a subject to provide the wholly aromatic polyester in which the generation|occurrence|production of the sublimate at the time of a polymerization reaction was little and foreign material was reduced, and this polyester resin composition.

The present inventors, as an essential component, consist of the following structural units (I), (II), (III) and (IV), with respect to all the structural units, the content of the structural unit (I) is 40 to 75 mol% and, with respect to all the structural units, the content of the structural unit (II) is 0.5 to 7.5 mol%, with respect to the entire structural unit, the content of the structural unit (III) is 8.5 to 30 mol%, with respect to the entire structural unit, The content of the structural unit (IV) is 8.5 to 30 mol%, and the total content of the structural units (I), (II), (III) and (IV) is 100 mol% with respect to all the structural units. In the wholly aromatic polyester, the inventors have found that the above problems can be solved by making the difference between the content of the structural unit (III) and the content of the structural unit (IV) 0.150 mol% or less, and the present inventors have completed the present invention came to More specifically, the present invention provides the following.

(1) As an essential component, it consists of the following structural units (I), (II), (III) and (IV),

With respect to all the constituent units, the content of constituent unit (I) is 40 to 75 mol%,

With respect to all the constituent units, the content of constituent unit (II) is 0.5 to 7.5 mol%,

With respect to all the constituent units, the content of constituent unit (III) is 8.5 to 30 mol%,

With respect to all the constituent units, the content of constituent unit (IV) is 8.5 to 30 mol%,

With respect to all the structural units, the total content of the structural units (I), (II), (III) and (IV) is characterized in that 100 mol%,

In the wholly aromatic polyester,

The wholly aromatic polyester, wherein the difference between the content of the structural unit (III) and the content of the structural unit (IV) is 0.150 mol% or less.

(2) A polyester resin composition containing the wholly aromatic polyester according to (1).

(3) A polyester molded article obtained by molding the wholly aromatic polyester or polyester resin composition according to (1) or (2).

(4) A method for producing a wholly aromatic polyester,

A process of acylating 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, and 4,4'-dihydroxybiphenyl with a fatty acid anhydride, and transesterifying with 1,4-phenylenedicarboxylic acid including,

With respect to all monomers consisting of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl,

The amount of 6-hydroxy-2-naphthoic acid used is 40 to 75 mol%,

The amount of 4-hydroxybenzoic acid used is 0.5 to 7.5 mol%,

The amount of 1,4-phenylenedicarboxylic acid used is 8.5 to 30 mol%,

The amount of 4,4'-dihydroxybiphenyl used is 8.5 to 30 mol%,

The total amount of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid and 4,4'-dihydroxybiphenyl used is 100 mol%,

A method for producing a wholly aromatic polyester, characterized in that the temperature is raised by dividing in stages from 140°C to 360°C.

(5) The method for producing a wholly aromatic polyester according to (4), wherein the stepwise elevated temperature is 140°C to 200°C, 200°C to 270°C, and 270°C to 360°C.

(6) The method for producing the wholly aromatic polyester according to (4) or (5), wherein the temperature increase rate from 140°C to 200°C is 0.4°C/min or more and less than 0.8°C/min.

(7) The method for producing the wholly aromatic polyester according to any one of (4) to (6), wherein the rate of temperature increase from 200°C to 270°C is 0.8°C/min or more and 1.2°C/min or less.

(8) The method for producing the wholly aromatic polyester according to any one of (4) to (7), wherein the rate of temperature increase from 270°C to 360°C is 0.4°C/min or more and 1.2°C/min or less.

Advantageous Effects of Invention According to the present invention, it is possible to provide a wholly aromatic polyester in which the generation of sublimates during a polymerization reaction is small and foreign substances are reduced, and a polyester resin composition thereof.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described in detail. This invention is not limited to the following embodiment, It can implement by adding a change suitably in the range which does not impair the effect of this invention. In the present invention, “A to B” means “A or more and B or less”.

[All Aromatic Polyester]

The wholly aromatic polyester according to the present invention, as an essential component, consists of the following structural units (I), (II), (III) and (IV), with respect to all the structural units, the content of the structural unit (I) is 40 to 75 mol%, with respect to all the structural units, the content of the structural unit (II) is 0.5 to 7.5 mol%, with respect to all the structural units, the content of the structural unit (III) is 8.5 to 30 mol%, With respect to all constituent units, the content of constituent unit (IV) is 8.5 to 30 mol%, and with respect to all constituent units, the total content of constituent units (I), (II), (III) and (IV) is 100 In the wholly aromatic polyester, characterized in that it is mol%, the difference between the content of the structural unit (III) and the content of the structural unit (IV) is 0.150 mol% or less, which is a wholly aromatic polyester.

The structural unit (I) is derived from 6-hydroxy-2-naphthoic acid (hereinafter also referred to as “HNA”). The wholly aromatic polyester of this invention contains 40-75 mol% of structural units (I) with respect to all structural units. When the content of the structural unit (I) is less than 40 mol%, the melting point is lowered and the heat resistance is insufficient. When the content of the structural unit (I) exceeds 75 mol%, solidification occurs during polymerization and no polymer is obtained. From the viewpoint of heat resistance and polymerizability, the content of the structural unit (I) is preferably 40 to 70 mol%, more preferably 40 to 65 mol%, still more preferably 40 to 63 mol%, and further Preferably it is 40-62 mol%, Especially preferably, it is 40-60 mol%.

The structural unit (II) is derived from 4-hydroxybenzoic acid (hereinafter also referred to as “HBA”). The wholly aromatic polyester of the present invention contains 0.5 to 7.5 mol% of the structural unit (II) based on all the structural units. When the content of the structural unit (II) is less than 0.5 mol%, solidification occurs during polymerization and no polymer is obtained. When the content of the structural unit (II) exceeds 7.5 mol%, the melting point is lowered and the heat resistance is insufficient. From the viewpoint of heat resistance and polymerizability, the content of the structural unit (II) is preferably 0.5 to 7.0 mol%, more preferably 1.0 to 7.0 mol%, still more preferably 1.2 to 7.0 mol%, and further Preferably it is 1.5-6.5 mol%, Especially preferably, it is 2.0-6.0 mol%.

The structural unit (III) is derived from 1,4-phenylenedicarboxylic acid (hereinafter also referred to as “TA”). The wholly aromatic polyester of the present invention contains 8.5 to 30 mol% of the structural unit (III) based on all the structural units. When the content of the structural unit (III) is less than 8.5 mol% or more than 30 mol%, at least one of low melting point and heat resistance tends to be insufficient. From a viewpoint of coexistence of low melting point and heat resistance, content of structural unit (III) becomes like this. Preferably it is 10-30 mol%, More preferably, it is 12-28 mol%, More preferably, it is 14-28 mol%. and more preferably 15 to 28 mol%, particularly preferably 17 to 27 mol%.

The structural unit (IV) is derived from 4,4'-dihydroxybiphenyl (hereinafter also referred to as "BP"). The wholly aromatic polyester of the present invention contains 8.5 to 30 mol% of the structural unit (IV) based on all the structural units. When the content of the structural unit (IV) is less than 8.5 mol% or exceeds 30 mol%, at least one of low melting point and heat resistance tends to be insufficient. From a viewpoint of coexistence of low melting point and heat resistance, content of structural unit (IV) becomes like this. Preferably it is 10-30 mol%, More preferably, it is 12-28 mol%, More preferably, it is 14-28 mol%. and more preferably 15 to 28 mol%, particularly preferably 17 to 27 mol%.

As described above, the wholly aromatic polyester of the present invention contains specific structural units (I) to (IV) in a specific amount with respect to all structural units, and the content of the structural unit (III) and the content of the structural unit (IV) Since the difference between the two is 0.150 mol% or less, the generation of sublimates during the polymerization reaction is small and foreign matter is reduced. Further, in the wholly aromatic polyester of the present invention, the difference between the content of the structural unit (III) and the content of the structural unit (IV) is preferably 0.145 mol% or less, more preferably 0.140 mol% or less, and 0.135 mol% or less It is more preferable, it is even more preferable that it is 0.130 mol% or less, and it is especially preferable that it is 0.125 mol% or less. In addition, the wholly aromatic polyester of the present invention contains 100 mol% of structural units (I) to (IV) in total with respect to all the structural units.

Next, the properties of the wholly aromatic polyester will be described. The wholly aromatic polyester of the present invention exhibits optical anisotropy upon melting. Showing optical anisotropy upon melting means that the wholly aromatic polyester of the present invention is a liquid crystalline polymer.

In the present invention, that the wholly aromatic polyester is a liquid crystalline polymer is an essential element for the wholly aromatic polyester to have both thermal stability and processability. The wholly aromatic polyester composed of the structural units (I) to (IV) does not form an anisotropic melt phase depending on the constituent components and the sequence distribution in the polymer. It is limited to the wholly aromatic polyester representing

The property of melt anisotropy can be confirmed by a conventional polarization inspection method using orthogonal polarizers. More specifically, confirmation of melt anisotropy can be performed by using the polarizing microscope by an Olympus company, melting the sample mounted on the Rinkham company hot stage, and observing at 150 times magnification in nitrogen atmosphere. Liquid crystalline polymers are optically anisotropic and transmit light when interposed between orthogonal polarizers. If the sample is optically anisotropic, for example, polarized light is transmitted even in the state of a melt stopper.

Since a nematic liquid crystalline polymer causes a marked decrease in viscosity above its melting point, in general, exhibiting liquid crystallinity at or above the melting point is an indicator of processability. The melting point is preferably as high as possible from the viewpoint of heat resistance, but considering the thermal deterioration during melt processing of the polymer or the heating capability of the molding machine, etc., it is a preferable standard that the melting point is 380°C or less. Moreover, More preferably, it is 260-370 degreeC, More preferably, it is 270-370 degreeC, Especially preferably, it is 280-360 degreeC.

The melt viscosity of the wholly aromatic polyester at a temperature 10 to 40° C. higher than the melting point of the wholly aromatic polyester of the present invention and at a shear rate of 1000/sec is preferably 1000 Pa·s or less, more preferably It is 4-500 Pa.s, More preferably, it is 4-250 Pa.s, Especially preferably, it is 5-100 Pa.s. When the melt viscosity is within the above range, the wholly aromatic polyester itself or the composition containing the wholly aromatic polyester tends to ensure fluidity during molding, and the filling pressure is unlikely to be excessive. In addition, melt viscosity in this specification refers to melt viscosity measured based on ISO11443.

Next, the manufacturing method of the wholly aromatic polyester of this embodiment is demonstrated. The wholly aromatic polyester of the present embodiment is polymerized using a direct polymerization method, a transesterification method, or the like. At the time of polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid-state polymerization method, or a combination of two or more thereof is used, and a melt polymerization method or a combination of a melt polymerization method and a solid-state polymerization method is preferably used.

In the present embodiment, an acylating agent for the polymerization monomer during polymerization or a monomer having an activated terminal as an acid chloride derivative can be used. Fatty acid anhydrides, such as acetic anhydride, are mentioned as an acylating agent.

In the method for producing the wholly aromatic polyester of this embodiment, the amount of fatty acid anhydride used is 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, and 4,4'-dihydroxy ratio from the viewpoint of color. It is preferably less than 1.08 times the hydroxyl equivalent of the total of phenyl, more preferably 1.00 to 1.07 times, still more preferably 1.01 to 1.07 times, still more preferably 1.01 to 1.06 times, and particularly preferably 1.02 to 1.06 times. .

Various catalysts can be used for these polymerizations, representative examples of which are potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, tris(2,4-pentanedionate) cobalt. and metal salt catalysts such as (III), and organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine.

The reaction consists of all raw material monomers (6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl), an acylating agent, and The catalyst may be put in the same reaction vessel to initiate the reaction (one-stage method), and 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, and 4,4'-dihydroxybiphenyl hydroxyl After acylation with an acylating agent, it may be reacted with the carboxyl group of 1,4-phenylenedicarboxylic acid (two-step method).

After the inside of the reaction system reaches a predetermined temperature, melt polymerization is performed by starting pressure reduction and setting it as a predetermined pressure reduction degree. After the torque of the stirrer reaches a predetermined value, an inert gas is introduced, and the wholly aromatic polyester is discharged from the reaction system through normal pressure from a reduced pressure state to a predetermined pressurization state.

The wholly aromatic polyester produced by the polymerization method can further increase the molecular weight by solid-state polymerization heated in an inert gas under normal pressure or reduced pressure.

In the method for producing the wholly aromatic polyester of the present embodiment, 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, and 4,4'-dihydroxybiphenyl are acylated with a fatty acid anhydride, It is preferable to include a step of transesterification with 1,4-phenylenedicarboxylic acid,

For all monomers consisting of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl,

The amount of 6-hydroxy-2-naphthoic acid used is 40 to 75 mol%, from the viewpoint of heat resistance and polymerizability, preferably 40 to 70 mol%, more preferably 40 to 65 mol%, still more preferably 40 to 63 mol%, more preferably 40 to 62 mol%, particularly preferably 40 to 60 mol%,

The amount of 4-hydroxybenzoic acid used is 0.5 to 7.5 mol%, from the viewpoint of heat resistance and polymerizability, preferably 0.5 to 7.0 mol%, more preferably 1.0 to 7.0 mol%, still more preferably 1.2 to 7.0 mol%, Even more preferably 1.5 to 6.5 mol%, particularly preferably 2.0 to 6.0 mol%,

The usage-amount of 1, 4- phenylenedicarboxylic acid is 8.5-30 mol%, From a viewpoint of coexistence of low melting point and heat resistance, Preferably 10-30 mol%, More preferably, 12-28 mol%, More preferably, 14 to 28 mol%, even more preferably 15 to 28 mol%, particularly preferably 17 to 27 mol%,

The amount of 4,4'-dihydroxybiphenyl used is 8.5 to 30 mol%, preferably 10 to 30 mol%, more preferably 12 to 28 mol%, and still more preferably from the viewpoint of achieving both low melting point and heat resistance. preferably 14 to 28 mol%, more preferably 15 to 28 mol%, particularly preferably 17 to 27 mol%,

It is preferable that the total amount of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl used is 100 mol%,

It is preferable to divide and raise the temperature in stages from 140°C to 360°C.

In the manufacturing method of the wholly aromatic polyester of this embodiment, it is preferable that the temperature rise divided|segmented into steps from 140 degreeC to 200 degreeC, 200 degreeC to 270 degreeC, and 270 degreeC to 360 degreeC.

In the manufacturing method of the wholly aromatic polyester of this embodiment, it is preferable that the rate of temperature increase from 140°C to 200°C is 0.4°C/min or more and less than 0.8°C/min, more preferably 0.5°C/min or more and less than 0.7°C/min. .

In the manufacturing method of the wholly aromatic polyester of this embodiment, it is preferable that the rate of temperature increase from 200°C to 270°C is 0.8°C/min or more and 1.2°C/min or less, and it is more preferable that they are 0.9°C/min or more and 1.1°C/min or less. .

In the method for producing the wholly aromatic polyester of the present embodiment, the temperature increase rate from 270°C to 360°C is preferably 0.4°C/min or more and 1.2°C/min or less, and more preferably 0.5°C/min or more and 1.1°C/min or less. .

In the production method of the wholly aromatic polyester of this embodiment, from the viewpoint of high molecular weight, the amount of 1,4-phenylenedicarboxylic acid used (mol%) and the amount of 4,4'-dihydroxybiphenyl used (mol%) are the same it is preferable Moreover, when a sublimate generate|occur|produces during manufacture of the wholly aromatic polyester of this embodiment, a difference arises in these content.

[Polyester resin composition]

In the wholly aromatic polyester of the present invention, various fibrous, granular, and plate-shaped inorganic and organic fillers may be blended according to the purpose of use.

The inorganic filler to be blended in the polyester resin composition of the present invention includes fibrous, granular, and plate-shaped ones.

Examples of the fibrous inorganic filler include glass fibers, milled glass fibers, asbestos fibers, silica fibers, silica/alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, silicate fibers such as wollastonite, magnesium sulfate, and the like. and inorganic fibrous substances such as fibers, aluminum borate fibers, and metal fibrous substances such as stainless steel, aluminum, titanium, copper, and brass. A particularly representative fibrous filler is glass fiber.

Examples of the particulate inorganic filler include silicates such as carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, wollastonite, iron oxide, titanium oxide, and zinc oxide. , metal oxides such as antimony trioxide and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, other ferrites, silicon carbide, silicon nitride, boron nitride, various metal powders, etc. have.

Moreover, as a plate-shaped inorganic filler, mica, a glass flake, a talc, various metal foil, etc. are mentioned.

Examples of the organic filler include heat-resistant, high-strength synthetic fibers such as aromatic polyester fibers, liquid crystalline polymer fibers, aromatic polyamides and polyimide fibers.

These inorganic and organic fillers can use 1 type or 2 or more types together. The combined use of a fibrous inorganic filler and a granular or plate-shaped inorganic filler is a preferable combination in order to have both mechanical strength, dimensional accuracy, electrical properties, and the like. Particularly preferably, glass fiber as the fibrous filler and mica and talc as the plate-like filler are used in an amount of 120 parts by mass or less, preferably 20 to 80 parts by mass, based on 100 parts by mass of the wholly aromatic polyester. By combining the glass fiber with mica or talc, the polyester resin composition has particularly remarkable improvement in heat deformation temperature, mechanical properties, and the like.

In the use of these fillers, if necessary, a sizing agent or a surface treatment agent may be used.

The polyester resin composition of the present invention, as described above, contains the wholly aromatic polyester of the present invention as an essential component and, if necessary, an inorganic or organic filler, as long as it does not impair the effects of the present invention, Other ingredients may be included. Here, other components may be arbitrary components, for example, additives, such as other resin, antioxidant, a stabilizer, a pigment, and a crystal nucleating agent, are mentioned.

In addition, the method for preparing the polyester resin composition of the present invention is not particularly limited, and the polyester resin composition can be prepared by a conventionally known method.

[Polyester molded article]

The polyester molded article of the present invention can be obtained by molding the wholly aromatic polyester or polyester resin composition of the present invention. The molding method is not particularly limited, and a general molding method can be adopted. As general molding methods, injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, inflation molding, and the like can be exemplified.

The polyester molded article obtained by molding the wholly aromatic polyester or the like of the present invention is excellent in heat resistance. In addition, the polyester molded article obtained by molding the polyester resin composition of the present invention is excellent in heat resistance and, if necessary, contains an inorganic or organic filler, so that mechanical strength and the like are further improved.

In addition, since the wholly aromatic polyester and polyester resin composition of the present invention have excellent moldability, they can be processed into various three-dimensional molded articles, fibers, films, and the like.

Preferred uses of the polyester molded article of the present invention having the above properties include connectors, CPU sockets, relay switch parts, bobbins, actuators, noise reduction filter cases, electronic circuit boards or heat fixing rolls for OA equipment. .

Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples.

<Example 1>

In a polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a reduced pressure/outlet line, the following raw material monomers, a fatty acid metal salt catalyst, and an acylating agent were put, and nitrogen substitution was initiated.

(I) 0.883 mol (48 mol%) of 6-hydroxy-2-naphthoic acid (HNA)

(II) 0.037 mol (2 mol%) of 4-hydroxybenzoic acid (HBA)

(III) 0.46 mol (25 mol%) of 1,4-phenylenedicarboxylic acid (TA)

(IV) 4,4'-dihydroxybiphenyl 0.46 mol (25 mol%) (BP)

150 ppm potassium acetate catalyst

Tris(2,4-pentanedionate) cobalt(III) catalyst 150ppm

1.91 moles of acetic anhydride (1.04 times the hydroxyl equivalent of the sum of HNA, HBA and BP)

After adding the raw materials, the temperature of the reaction system was raised to 140°C, and the reaction was performed at 140°C for 1 hour. Thereafter, the temperature was further raised under the rate conditions shown in Table 1, and the pressure was reduced thereto to 10 Torr (ie, 1330 Pa) for 20 minutes, and melt polymerization was performed while acetic acid, excess acetic anhydride and other low boiling components were discharged. After the stirring torque reached a predetermined value, nitrogen was introduced to bring the pressure from reduced pressure to atmospheric pressure, and the product was discharged from the lower part of the polymerization vessel to pelletize, thereby obtaining a pelletized prepolymer. The obtained prepolymer was heat-treated (solid-state polymerization) at 300 DEG C under a nitrogen stream for 3 hours to obtain the target polymer.

[Sublimation Amount]

In the melt polymerization described above, the amount of sublimate was measured from the change in weight of the reflux column and the upper part of the reactor. An evaluation result is shown in Table 1.

<Evaluation>

With respect to the wholly aromatic polyester of Example 1, evaluation of melting|fusing point, melt viscosity, the amount of terminal groups, and foreign material was performed by the following method. An evaluation result is shown in Table 1.

[melting point]

After measurement of the endothermic peak temperature (Tm1) observed when the wholly aromatic polyester is heated from room temperature to 20°C/min. The temperature of the endothermic peak observed when the temperature was maintained at a temperature of ℃ for 2 minutes, cooled to room temperature under a temperature decrease condition of 20°C/min, and then heated again at a temperature increase condition of 20°C/min was measured.

[Melt Viscosity]

Melting of wholly aromatic polyester in accordance with ISO11443 at a shear rate of 1000/sec using an orifice having an inner diameter of 0.5 mm and a length of 30 mm at a temperature of 380°C using a capillograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.) The viscosity was measured.

[Monomer composition (content)]

The monomer composition was calculated by the pyrolysis gas chromatography method described in Polymer Degradation and Stability 76 (2002) 85-94. Specifically, using a thermal decomposition device (“PY2020iD” manufactured by Frontier Labo Co., Ltd.), the wholly aromatic polyester was heated in the presence of tetramethyl ammonium hydroxide (TMAH), and gas was generated by thermal decomposition/methylation. This gas was analyzed using gas chromatography ("GC-6890N" manufactured by Agilent Technology Co., Ltd.), and the peak area and 4,4'-dihydroxy ratio derived from 1,4-phenylenedicarboxylic acid From the ratio of the peak area derived from phenyl, the difference between the content of the structural unit derived from 1,4-phenylenedicarboxylic acid and the content of the structural unit derived from 4,4'-dihydroxybiphenyl was calculated.

[alien substance]

The wholly aromatic polyester was film-formed (0.5 g/sheet, film thickness 100 micrometers) using the high temperature compatible hot press machine ("NP-SNH" manufactured by Toyo Seiki Seisakusho Co., Ltd.). A white backlight was illuminated on the film, and the number of foreign objects of 0.3 mm or more was checked using a magnifying glass. Confirmation of the number of this foreign material was performed with respect to 5 films (2.5 g), and the number of foreign material per unit weight was calculated|required. The case where the number of foreign substances was 0 pieces/g was indicated by "○", and the case where the number of foreign substances was 1 piece/g or more was indicated as "x".

<Examples 2 to 4, Comparative Examples 1 to 10>

A polymer was obtained in the same manner as in Example 1, except that the type of raw material monomer, the amount used (mol%), and the temperature increase rate were as shown in Tables 1 and 2. In addition, evaluation similar to Example 1 was performed (The melt viscosity of Example 4 and Comparative Example 4 was measured at the temperature of 350 degreeC). An evaluation result is shown in Table 1 and Table 2.

Example
One Example
2 Example
3 Example
4 comparative example
One comparative example
2 comparative example
3 comparative example
4
monomer
Furtherance
(usage) HNA mole% 48 48 40 60 48 48 40 60 HBA mole% 2 2 6 6 2 2 6 6 TA mole% 25 25 27 17 25 25 27 17 BP mole% 25 25 27 17 25 25 27 17 Sum mole% 100 100 100 100 100 100 100 100
temperature rise rate 140-200℃ °C/min 0.60 0.60 0.60 0.60 0.60 0.40 0.60 0.60 200-270℃ °C/min 1.00 1.00 1.00 1.00 1.00 0.60 1.00 1.00 270-360℃ °C/min 0.50 1.00 0.75 0.50 1.50 1.50 1.50 1.50 temperature rise time minute 321 247 279 321 201 241 201 201 sublimation amount weight% 1.6 1.9 1.8 1.9 2.6 2.5 2.5 2.4 melting point ℃ 348 348 347 318 349 348 348 317 melt viscosity Pa·s 9 11 10 11 11 10 9 9 The difference between the content of TA and the content of BP mole% 0.102 0.121 0.115 0.125 0.167 0.173 0.159 0.173 alien substance - ○ ○ ○ ○ × × × ×

comparative example
5 comparative example
6 comparative example
7 comparative example
8 comparative example
9 comparative example
10
monomer
Furtherance
(usage) HNA mole% 48 48 48 48 48 48 HBA mole% 2 2 2 2 2 2 TA mole% 25 25 25 25 25 25 BP mole% 25 25 25 25 25 25 Sum mole% 100 100 100 100 100 100
temperature rise rate 140-200℃ °C/min 0.69 0.40 0.80 0.30 0.89 0.40 200-270℃ °C/min 0.69 1.30 1.08 1.00 0.80 0.80 270-360℃ °C/min 0.68 0.40 0.30 0.70 0.46 1.29 temperature rise time minute 321 321 321 321 321 247 sublimation amount weight% 2.4 2.6 2.5 2.7 2.5 2.9 melting point ℃ 348 349 349 348 347 349 melt viscosity Pa·s 10 9 12 11 12 9 The difference between the content of TA and the content of BP mole% 0.171 0.172 0.167 0.188 0.165 0.217 alien substance - × × × × × ×

In addition, as shown in Table 2, foreign matter was generated in Comparative Example 8 in which the temperature increase rate from 140°C to 200°C was 0.30°C/min and Comparative Example 9 in which the rate was 0.89°C/min. In addition, as shown in Tables 1 and 2, in Comparative Example 2 where the rate of temperature increase from 200°C to 270°C was 0.60°C/min, Comparative Example 5 was 0.69°C/min, and Comparative Example 6 was 1.30°C/min, foreign matter was generated. In addition, as shown in Tables 1 and 2, foreign matter was also generated in Comparative Examples 1 to 4, in which the rate of temperature increase from 270°C to 360°C was 1.50°C/min, Comparative Example 7, in which the rate was 0.30°C/min, and Comparative Example 10, in which the rate was 1.29°C/min. .

Claims (8)

As an essential component, it consists of the following structural units (I), (II), (III) and (IV),
With respect to all the structural units, the content of the structural unit (I) is 40 to 75 mol%,
With respect to all the constituent units, the content of constituent unit (II) is 0.5 to 7.5 mol%,
With respect to all the constituent units, the content of constituent unit (III) is 8.5 to 30 mol%,
With respect to all the constituent units, the content of constituent unit (IV) is 8.5 to 30 mol%,
With respect to all the structural units, the total content of the structural units (I), (II), (III) and (IV) is characterized in that 100 mol%,
In the wholly aromatic polyester,
The wholly aromatic polyester, wherein the difference between the content of the structural unit (III) and the content of the structural unit (IV) is 0.150 mol% or less.
[Formula 1]

A polyester resin composition containing the wholly aromatic polyester according to claim 1. A polyester molded article obtained by molding the wholly aromatic polyester or polyester resin composition according to claim 1 or 2. A method for producing a wholly aromatic polyester, comprising:
A process of acylating 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, and 4,4'-dihydroxybiphenyl with a fatty acid anhydride, and transesterifying with 1,4-phenylenedicarboxylic acid includes,
With respect to all monomers consisting of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl,
The amount of 6-hydroxy-2-naphthoic acid used is 40 to 75 mol%,
The amount of 4-hydroxybenzoic acid used is 0.5 to 7.5 mol%,
The amount of 1,4-phenylenedicarboxylic acid used is 8.5 to 30 mol%,
The amount of 4,4'-dihydroxybiphenyl used is 8.5 to 30 mol%,
The total amount of 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, and 4,4'-dihydroxybiphenyl used is 100 mol%,
A method for producing a wholly aromatic polyester, characterized in that the temperature is raised by dividing in stages from 140°C to 360°C. 5. The method of claim 4,
The stepwise elevated temperature is a temperature increase divided from 140° C. to 200° C., 200° C. to 270° C., and 270° C. to 360° C., a method for producing a wholly aromatic polyester. 6. The method according to claim 4 or 5,
The method for producing a wholly aromatic polyester, wherein the rate of temperature increase from 140°C to 200°C is 0.4°C/min or more and less than 0.8°C/min. 7. The method according to any one of claims 4 to 6,
A method for producing a wholly aromatic polyester, wherein the rate of temperature increase from 200°C to 270°C is 0.8°C/min or more and 1.2°C/min or less. 8. The method according to any one of claims 4 to 7,
A method for producing a wholly aromatic polyester, wherein the rate of temperature increase from 270°C to 360°C is 0.4°C/min or more and 1.2°C/min or less.