JP6189750B2 - Totally aromatic polyester, polyester resin composition, and polyester molded article - Google Patents

Description

  The present invention relates to a wholly aromatic polyester, a polyester resin composition, and a polyester molded article.

  What is currently marketed as a fully aromatic polyester is based on 4-hydroxybenzoic acid. However, since the homopolymer of 4-hydroxybenzoic acid has a melting point higher than the decomposition point, it is necessary to lower the melting point by copolymerizing various components.

  For example, wholly aromatic polyesters using 1,4-phenylenedicarboxylic acid, 1,4-dihydroxybenzene, 4,4'-dihydroxybiphenyl, and the like as copolymerization components are known. However, the melting point of this wholly aromatic polyester is 350 ° C. or higher, which is too high for melt processing with a general-purpose apparatus.

  In addition, various methods have been tried to lower the melting point of such wholly aromatic polyesters to a temperature at which they can be processed by general-purpose melt processing equipment. However, there is a problem that the heat resistance of the wholly aromatic polyester, represented by mechanical strength at a high temperature (near the melting point), cannot be maintained while lowering the melting point to some extent.

  In order to solve these problems, Patent Documents 1 and 2 propose a copolyester in which 6-hydroxy-2-naphthoic acid, a diol component, and a dicarboxylic acid component are combined.

JP 59-62630 A JP-A-63-275628

  However, the copolyesters proposed in Patent Documents 1 and 2 have low toughness and have a problem that cracks occur in the molded product during molding.

  An object of the present invention is to provide a wholly aromatic polyester that solves the above problems and is excellent in heat resistance and toughness.

  The present inventors have intensively studied to solve the above problems. As a result, the wholly aromatic polyester is composed of structural units represented by the following general formulas (I), (II), (III), (IV) and (V). Is 40 to 70 mol%, (II) is 7 to 14 mol%, (III) is 8 to 26.5 mol%, and (IV) is 0 to 10 mol%. When the structural unit of (V) is 8 to 26.5 mol% and the total of the structural unit of (II) and the structural unit of (IV) is 12 to 17 mol%, the above problem can be solved. The headline and the present invention were completed. More specifically, the present invention provides the following.

  (1) It is composed of structural units represented by the following general formulas (I), (II), (III), (IV) and (V) as essential structural components. Is 40 to 70 mol%, (II) is 7 to 14 mol%, (III) is 8 to 26.5 mol%, and (IV) is 0 to 10 mol%. (V) is 8 to 26.5 mol%, and the total of the structural unit (II) and the structural unit (IV) is 12 to 17 mol%. Wholly aromatic polyester showing mechanical anisotropy.

  (2) The wholly aromatic polyester according to (1), wherein 1 to 8 mol% of the structural unit (IV) is contained.

(3) The wholly aromatic according to (1) or (2), wherein the melt viscosity at a shear rate of 1000 sec ⁻¹ is 1 × 10 ⁵ Pa · s or less at a temperature 10 to 40 ° C. higher than the melting point of the wholly aromatic polyester. polyester.

  (4) The wholly aromatic polyester according to any one of (1) to (3), wherein the melting point is 300 to 390 ° C.

  (5) A polyester resin composition comprising 120 parts by mass or less of an inorganic filler or an organic filler with respect to 100 parts by mass of the wholly aromatic polyester according to any one of (1) to (4).

  (6) A polyester resin composition obtained by blending 20 to 80 parts by mass of an inorganic filler or an organic filler with respect to 100 parts by mass of the wholly aromatic polyester according to any one of (1) to (4).

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

  (8) The polyester molded product according to (7), wherein the polyester molded product is a connector, a CPU socket, a relay switch component, a bobbin, an actuator, a noise reduction filter case, or a heat fixing roll of an OA device.

  (9) The polyester molded product according to (7), wherein the polyester molded product is a polyester fiber.

  (10) The polyester molded product according to (7), wherein the polyester molded product is a polyester film.

  According to the present invention, the wholly aromatic polyester of the present invention comprising a specific structural unit and exhibiting optical anisotropy at the time of melting, and the polyester resin composition containing the wholly aromatic polyester have fluidity at the time of melting. It is good and has excellent heat resistance and toughness when formed into a molded product.

  In addition, the wholly aromatic polyester or polyester resin composition of the present invention is not so high in molding processing temperature that it can be injection molded, extruded and compressed without using a molding machine having a special structure. .

  As described above, the wholly aromatic polyester or polyester resin composition of the present invention is excellent in moldability and can be molded using various molding machines. As a result, it can be easily formed into various three-dimensional molded products, fibers, films, and the like. Can be processed. For this reason, molded articles such as connectors, CPU sockets, relay switch parts, bobbins, actuators, noise reduction filter cases, or heat fixing rolls for OA equipment, which are suitable uses of the wholly aromatic polyester or polyester resin composition of the present invention. Is also easily obtained.

It is a schematic diagram which shows the molded article manufactured in Example 9 and 10, and Comparative Examples 9 and 10, (a) is the top view, (b) is a figure which shows the dimension. In addition, the unit of the numerical value in a figure is mm.

  Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment.

<Totally aromatic polyester>
The wholly aromatic polyester of the present invention is composed of structural units represented by the following general formulas (I), (II), (III), (IV) and (V).

  The structural unit represented by the general formula (I) is 4-hydroxybenzoic acid (HBA). The wholly aromatic polyester of the present invention contains 40 to 70 mol% of HBA with respect to all the structural units. When the content of HBA is less than 40 mol% or more than 70 mol%, the melting point of the wholly aromatic polyester is remarkably increased, and in some cases, the wholly aromatic polyester is solidified in the reactor at the time of production, and a polymer having a desired molecular weight Is not preferable because it cannot be produced.

  The structural unit represented by the general formula (II) is 6-hydroxy-2-naphthoic acid (HNA). The wholly aromatic polyester of the present invention contains 7 to 14 mol% of HNA with respect to all the structural units. When the content of HNA is less than 7 mol%, the melting point of the oligomer is remarkably increased during the production of the wholly aromatic polyester, and in some cases, the wholly aromatic polyester is solidified in the reactor during the production, and a polymer having a desired molecular weight is obtained. This is not preferable because it cannot be manufactured. On the other hand, if the HNA content exceeds 14 mol%, the heat resistance of the wholly aromatic polyester of the present invention is lowered, which is not preferable.

  The structural unit represented by the general formula (III) is 1,4-phenylenedicarboxylic acid (TA). The wholly aromatic polyester of the present invention contains 8 to 26.5 mol% of TA with respect to all the structural units. When the TA content is less than 8 mol% or exceeds 26.5 mol%, the melting point of the wholly aromatic polyester is remarkably increased, and in some cases, the wholly aromatic polyester is solidified in the reactor during the production, and the desired molecular weight is obtained. This is not preferable because the polymer cannot be produced.

  The structural unit represented by the general formula (IV) is 1,3-phenylenedicarboxylic acid (IA). The wholly aromatic polyester of the present invention contains 0 to 10 mol% of IA with respect to all structural units. When the content of IA exceeds 10 mol%, the heat resistance of the wholly aromatic polyester is lowered, which is not preferable.

  The structural unit represented by the general formula (V) is 1,4-benzenediol (HQ). The wholly aromatic polyester of the present invention contains 8 to 26.5 mol% of HQ with respect to all the structural units. When the content of HQ is less than 8 mol% or exceeds 26.5 mol%, the melting point of the wholly aromatic polyester may be extremely high in some cases, and the wholly aromatic polyester is solidified in the reactor at the time of manufacture. This is not preferable because the polymer cannot be produced.

  In the wholly aromatic polyester of the present invention, the total content of the constituent unit of (II) and the constituent unit of (IV) is 12 to 17 mol% with respect to all constituent units. When the total content is less than 12 mol%, the toughness of the polyester molded product formed by molding the wholly aromatic polyester or polyester resin composition of the present invention is not preferable. Moreover, since the heat resistance of a wholly aromatic polyester will become low when the said total content exceeds 17 mol%, it is unpreferable.

  As described above, the wholly aromatic polyester of the present invention contains a specific amount of each of the specific structural units (I) to (V) with respect to the total structural units, and further includes the structural unit of (II) And the total content of the structural units of (IV) are adjusted to a specific range, it has heat resistance, and the toughness of a polyester molded product formed by molding the wholly aromatic polyester of the present invention is also increased.

  Examples of the index representing the toughness include the amount of crystallization heat of the wholly aromatic polyester. When the amount of heat of crystallization is 2.7 J / g or more, the toughness tends to decrease, which is not preferable. The preferable value of the amount of crystallization heat is 2.5 J / g or less, more preferably 2.2 J / g or less. This amount of crystallization can be determined by differential calorimetry. In addition, in the case of the polyester resin composition of this invention mentioned later, the crystallization calorie | heat amount of a polyester resin composition is considered. In the case of the polyester resin composition, the preferred range is the same.

Moreover, the wholly aromatic polyester of the present invention is excellent in moldability. The moldability of the wholly aromatic polyester can be expressed by the fluidity at the time of melting of the wholly aromatic polyester. Specifically, the melt viscosity at a shear rate of 1000 sec ⁻¹ at a temperature 10 to 40 ° C. higher than the melting point is preferably 1 × 10 ⁵ Pa · s or less. More preferably, it is 5 Pa · s or more and 1 × 10 ² Pa · s or less. These melt viscosities are generally realized by having liquid crystal properties described later. In addition, in the case of the polyester resin composition of this invention mentioned later, the melt viscosity of a polyester resin composition is considered. In the case of the polyester resin composition, the preferred range is the same.

  In addition, in the wholly aromatic polyester of the present invention, structural units other than the structural units represented by the above (I) to (V) may be included within a range that does not impair the effects of the present invention. Moreover, if it is trace amount, the structural unit which does not have aromaticity may be included.

  Subsequently, the manufacturing method of the wholly aromatic polyester of this invention is demonstrated. The wholly aromatic polyester of the present invention is polymerized using a direct polymerization method or a transesterification method. In the polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid phase polymerization method, or the like is used.

  In the present invention, at the time of polymerization, an acylating agent for the polymerization monomer or a monomer having terminal activated as an acid chloride derivative can be used. Examples of the acylating agent include acid anhydrides such as acetic anhydride.

In the polymerization, various catalysts can be used. Typical examples include dialkyl tin oxides, diaryl tin oxides, titanium dioxide, alkoxy titanium silicates, titanium alcoholates, alkalis and alkalis of carboxylic acids. Examples include earth metal salts and Lewis acid salts such as BF ₃ . The amount of the catalyst used is generally about 0.001 to 1% by weight, particularly about 0.003 to 0.2% by weight, based on the total weight of the monomers.

  Moreover, when performing solution polymerization or slurry polymerization, as a solvent, liquid paraffin, a high heat resistant synthetic oil, an inert mineral oil, etc. are used.

  The reaction conditions are, for example, a reaction temperature of 200 to 380 ° C. and a final ultimate pressure of 0.1 to 760 Torr (that is, 13 to 101,080 Pa). Particularly in the melt reaction, for example, the reaction temperature is 260 to 380 ° C., preferably 300 to 360 ° C., the final ultimate pressure is 1 to 100 Torr (that is, 133 to 13,300 Pa), preferably 1 to 50 Torr (that is, 133 to 6,670 Pa). ).

  In the reaction, all the raw material monomers, the acylating agent and the catalyst can be charged in the same reaction vessel to start the reaction (one-stage system), or the hydroxyl groups of the raw material monomers (I), (II) and (V) are acylated. After acylating with an agent, it can also be reacted with the carboxyl groups of (III) and (IV) (two-stage system).

  The melt polymerization is performed after the inside of the reaction system reaches a predetermined temperature, and after starting the pressure reduction to a predetermined degree of pressure reduction. After the torque of the stirrer reaches a predetermined value, an inert gas is introduced, and the total aromatic polyester is discharged from the reaction system by changing from a reduced pressure state to a normal pressure to a predetermined pressure state.

  The wholly aromatic polyester produced by the polymerization method can be further increased in molecular weight by solid-phase polymerization that is heated in an inert gas at normal pressure or reduced pressure. The preferable conditions for the solid state polymerization reaction are a reaction temperature of 230 to 350 ° C., preferably 260 to 330 ° C., and a final ultimate pressure of 10 to 760 Torr (ie 1,330 to 101,080 Pa).

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

  In the present invention, the fact that the wholly aromatic polyester is a liquid crystalline polymer is an indispensable element for the wholly aromatic polyester has both thermal stability and easy processability. The wholly aromatic polyester composed of the structural units (I) to (V) may not form an anisotropic melt phase depending on the constituent components and the sequence distribution in the polymer. Limited to wholly aromatic polyesters that exhibit optical anisotropy when melted.

  The property of melt anisotropy can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, the melting anisotropy can be confirmed by melting a sample placed on a hot stage manufactured by Linkham Co., Ltd. using a polarizing microscope manufactured by Olympus and observing it at a magnification of 150 times in a nitrogen atmosphere. The liquid crystalline polymer is optically anisotropic and transmits light when inserted between crossed polarizers. If the sample is optically anisotropic, for example, polarized light is transmitted even in a molten stationary liquid state.

  Since a nematic liquid crystalline polymer causes a significant decrease in viscosity at the melting point or higher, generally exhibiting liquid crystallinity at the melting point or higher is an index of workability. The melting point (liquid crystallinity expression temperature) is preferably as high as possible from the viewpoint of heat resistance, but it is 300 to 390 ° C. in consideration of thermal degradation during polymer melt processing, heating capability of the molding machine, and the like. Is a preferred guideline. In addition, More preferably, it is 380 degrees C or less.

<Polyester resin composition>
Various fibrous, granular, and plate-like inorganic and organic fillers can be blended in the wholly aromatic polyester of the present invention according to the purpose of use.

  As an inorganic filler mix | blended with the polyester resin composition of this invention, there exist a fibrous form, a granular form, and a plate-shaped thing.

  Silica such as glass fiber, asbestos fiber, silica fiber, silica / alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, wollastonite as fibrous inorganic filler Fiber, magnesium sulfate fiber, aluminum borate fiber, and inorganic fibrous materials such as metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. A particularly typical fibrous filler is glass fiber.

  In addition, as the granular inorganic filler, carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber, glass balloon, glass powder, calcium oxalate, aluminum oxalate, kaolin, clay, diatomaceous earth, wollast Silicates such as knight, iron oxide, titanium oxide, zinc oxide, antimony trioxide, metal oxides such as alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate Examples thereof include salts, other ferrites, silicon carbide, silicon nitride, boron nitride, and various metal powders.

  Examples of the plate-like inorganic filler include mica, glass flakes, talc, and various metal foils.

  Examples of organic fillers 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 be used alone or in combination of two or more. The combined use of the fibrous inorganic filler and the granular or plate-like inorganic filler is a preferable combination in order to combine mechanical strength, dimensional accuracy, electrical properties, and the like. Particularly preferably, the fibrous filler is glass fiber, and the plate-like filler is mica and talc. It is. In addition, it is preferable that the fiber length of glass fiber is 200 micrometers or more. By combining such glass fibers with mica or talc, the polyester resin composition is particularly prominent in improving the heat distortion temperature and mechanical properties.

  In using these fillers, if necessary, a sizing agent or a surface treatment agent can be used.

  As described above, the polyester resin composition of the present invention contains the wholly aromatic polyester of the present invention, an inorganic or organic filler as an essential component, but other components are included as long as the effects of the present invention are not impaired. It may be included. Here, the other component may be any component, and examples thereof include other resins, antioxidants, stabilizers, pigments, crystal nucleating agents and the like.

  Moreover, the manufacturing method of the polyester resin composition of this invention is not specifically limited, A polyester resin composition can be prepared by a conventionally well-known method.

<Polyester molded product>
The polyester molded article of the present invention is formed 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 employed. Examples of general molding methods include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, and the like.

  A polyester molded product formed by molding the wholly aromatic polyester of the present invention is excellent in heat resistance and toughness. Moreover, since the polyester molded article formed by shape | molding the polyester resin composition of this invention is excellent in heat resistance and toughness and contains an inorganic or organic filler, mechanical strength etc. are further improved.

  Moreover, since the wholly aromatic polyester and the polyester resin composition of the present invention are excellent in moldability, a polyester molded product having a desired shape can be easily obtained.

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to a following example.

<Example 1>
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction / outflow line was charged with the following raw material monomers, a metal catalyst, and an acylating agent, and nitrogen substitution was started.
(I) 136 g (41 mol%) of 4-hydroxybenzoic acid (HBA)
(II) 6-hydroxy-2-naphthoic acid 41 g (9 mol%) (HNA)
(III) 71 g (17.7 mol%) of terephthalic acid (TA)
(IV) 30 g (7.5 mol%) of isophthalic acid (IA)
(V) 1,4-benzenediol 66 g (24.8 mol%) (HQ)
Potassium acetate catalyst 15mg
252 g of acetic anhydride
After charging the raw materials, the temperature of the reaction system was raised to 140 ° C. and reacted at 140 ° C. for 1 hour. Thereafter, the temperature is further raised to 360 ° C. over 5.5 hours, and then reduced to 10 Torr (ie, 1330 Pa) over 20 minutes to melt while distilling acetic acid, excess acetic anhydride, and other low-boiling components. Polymerization was performed. After the stirring torque reached a predetermined value, nitrogen was introduced and the pressure was changed from a reduced pressure state to a normal pressure, and the polymer was discharged from the lower part of the polymerization vessel.

<Evaluation>
About the wholly aromatic polyester of Example 1, evaluation of melting | fusing point, crystallization temperature, crystallization calorie | heat amount, melt viscosity, and softening temperature was performed with the following method. The evaluation results are shown in Table 1.

[Melting point]
After observing the endothermic peak temperature (Tm1) observed when the polymer was measured at room temperature to 20 ° C./min on a DSC manufactured by Perkin Elmer, the polymer was held at a temperature of (Tm1 + 40) ° C. for 2 minutes. The sample was once cooled to room temperature under a temperature drop condition of 20 ° C./min, and then the temperature of an endothermic peak observed when measured under a temperature rise condition of 20 ° C./min was measured again.

[Crystallizing temperature]
After observing the endothermic peak temperature (Tm1) observed when the polymer was measured at room temperature to 20 ° C./min on a DSC manufactured by Perkin Elmer, the polymer was held at a temperature of (Tm1 + 40) ° C. for 2 minutes. The exothermic peak temperature observed when measured under a temperature drop condition of 20 ° C./min was measured.

[Amount of crystallization]
After observing the endothermic peak temperature (Tm1) observed when the polymer was measured at room temperature to 20 ° C./min on a DSC manufactured by Perkin Elmer, the polymer was held at a temperature of (Tm1 + 40) ° C. for 2 minutes. The calorific value of the exothermic peak obtained from the peak of the exothermic peak temperature observed when the temperature was measured under a temperature drop condition of 20 ° C./min was measured.

[Melt viscosity]
The melt viscosity at a shear rate of 1000 sec ⁻¹ was calculated at a temperature 10 to 20 ° C. higher than the melting point using an orifice with an inner diameter of 1 mm and a length of 20 mm, measured by a Toyo Seiki Capillograph.

[Softening temperature]
A disk with a thickness of 1 mm was formed from the prepared polyester with a hot press, and the temperature was increased at 20 ° C./min on a hot plate while applying a constant load of 12.7 MPa to the molded article. The temperature at which the needle reached 5% of the thickness of the molded product was defined as the softening temperature.

<Examples 2 to 6, 8, Comparative Examples 1 to 8, Reference Example 1 >
A polymer was obtained in the same manner as in Example 1 except that the types of raw material monomers and the charging ratio (mol%) were as shown in Tables 1 and 2. Moreover, the same evaluation as Example 1 was performed. The evaluation results are also shown in Tables 1 and 2. In Comparative Examples 1, 2, and 4, the polymer solidified in the reactor during production, and a polymer having a desired molecular weight could not be produced (denoted as NG in the table).

<Examples 9 to 10 and Comparative Examples 9 to 10>
Example 9 is a wholly aromatic polyester of Example 6, glass fiber: ECS03T-786H manufactured by Nippon Electric Glass Co., Ltd., chopped strand having a fiber diameter of 10 μm and a length of 3 mm, and mica: Yamaguchi Mica Industry Co., Ltd. AB-25S manufactured and the average particle size of 25 μm are used in the formulation shown in Table 3 (contents described with respect to 100 parts by mass of wholly aromatic polyester) and compounded and kneaded by a twin screw extruder (TEX 30α manufactured by Nippon Steel). Thus, a pellet-shaped wholly aromatic polyester composition was obtained. After drying this wholly aromatic polyester composition at 140 ° C. for 3 hours, the molded product shown in FIG. 1 was injection molded under the following molding conditions using an injection molding machine. It did not occur and showed good toughness characteristics. The results are shown in Table 3. The evaluation injection-molded product shown in FIG. 1 has an outer diameter of 23.6 mm, 31 holes with a diameter of 3.2 mm, and a minimum wall thickness of 0.16 mm. The gate is indicated by the arrow in FIG. 1 (three-point gate). Use a stereomicroscope to observe the cracking of the molded product at a magnification of 5 times, and observe the occurrence of cracks around the hole. If there was a crack in the molded product, “X”; if not, “○” It was judged. In addition, FIG.1 (b) represents the dimension of the injection molded product for evaluation used in the Example. Since FIG. 1 (b) is a diagram for explaining the dimensions, only one hole is shown, but actually, 31 holes are formed on a surface of φ22.2 mm.
(Molding condition)
Molding machine; Sumitomo Heavy Industries SE30DUZ
Cylinder temperature; (Nozzle) 350 ° C.-355 ° C.-340 ° C.-330 ° C. (Example 9)
Mold temperature: 140 ° C
Injection speed: 50 mm / min
Holding pressure: 100 MPa
Holding time: 2 sec
Cooling time: 10 sec
Screw rotation speed: 120rpm
Screw back pressure: 1.2 MPa

  Example 10 uses the wholly aromatic polyester of Example 5 and uses glass fiber and mica in the same manner as in Example 9 in the formulation shown in Table 3. A twin-screw extruder (TEX 30α manufactured by Nippon Steel Works) ) To obtain a pellet-shaped wholly aromatic polyester composition. After drying this wholly aromatic polyester composition at 140 ° C. for 3 hours, the molded product was injection-molded using an injection molding machine in the same manner as in Example 9. As a result, the moldability was good and cracks in the molded product did not occur. Showed good toughness characteristics. The results are shown in Table 3. In the molding conditions, only the cylinder temperature condition was changed to 360 ° C.-365 ° C.-350 ° C.-340 ° C.

  Comparative Example 9 uses the wholly aromatic polyester of Comparative Example 6 and uses glass fiber and mica in the same manner as in Example 9 in the formulation shown in Table 3 and is a twin screw extruder (TEX 30α manufactured by Nippon Steel Works). After mixing and kneading to obtain a pellet-shaped wholly aromatic polyester composition, the molded product was injection-molded in the same manner as in Example 9 to evaluate toughness (cracking of the molded product). These results are shown in Table 3. In the molding conditions, only the cylinder temperature conditions were changed to 390 ° C-395 ° C-380 ° C-370 ° C.

  Comparative Example 10 uses the wholly aromatic polyester of Comparative Example 8 and uses glass fibers and mica in the same manner as in Example 9 in the formulation shown in Table 3 and is a twin-screw extruder (TEX 30α manufactured by Nippon Steel Works). After mixing and kneading to obtain a pellet-shaped wholly aromatic polyester composition, the molded product was injection-molded in the same manner as in Example 9 to evaluate toughness (cracking of the molded product). These results are shown in Table 3. In addition, only the conditions of the cylinder temperature in the molding conditions were changed to 380 ° C.-385 ° C.-370 ° C.-360 ° C.

  For Examples 9 to 10 and Comparative Examples 9 to 10, evaluations of melting point, crystallization temperature, crystallization heat amount, melt viscosity, and softening temperature were performed in the same manner as in Example 1 and the like. The evaluation results are shown in Table 3.

Claims (10)

It is composed of structural units represented by the following general formulas (I), (II), (III), (IV) and (V) as essential structural components,
The structural unit of (I) is 40 to 70 mol%,
7 to 14 mol% of the structural unit of (II),
The structural unit of (III) is 11.7 to 26.5 mol%,
0 to 10 mol% of the structural unit of (IV),
The structural unit of (V) is 8 to 26.5 mol%,
A wholly aromatic polyester exhibiting optical anisotropy when melted, wherein the total of the structural unit of (II) and the structural unit of (IV) is 12 to 17 mol%.
  The wholly aromatic polyester according to claim 1, wherein the structural unit (IV) is contained in an amount of 1 to 8 mol%. 3. The wholly aromatic polyester according to claim ^1, wherein the melt viscosity at a shear rate of 1000 sec ⁻¹ is 1 × 10 ⁵ Pa · s or less at a temperature 10 to 40 ° C. higher than the melting point of the wholly aromatic polyester.   The wholly aromatic polyester according to any one of claims 1 to 3, which has a melting point of 300 to 390 ° C.   The polyester resin composition formed by mix | blending 120 mass parts or less of an inorganic filler or an organic filler with respect to 100 mass parts of all aromatic polyesters of any one of Claims 1-4.   The polyester resin composition formed by mix | blending 20-80 mass parts of inorganic fillers or organic fillers with respect to 100 mass parts of wholly aromatic polyesters of any one of Claims 1-4.   The polyester molded product formed by shape | molding the wholly aromatic polyester of any one of Claims 1-4, or the polyester resin composition of Claim 5 or 6.   The polyester molded article according to claim 7, wherein the polyester molded article is a connector, a CPU socket, a relay switch component, a bobbin, an actuator, a noise reduction filter case, or a heat fixing roll of an OA device.   The polyester molded article according to claim 7, wherein the polyester molded article is a polyester fiber.   The polyester molded product according to claim 7, wherein the polyester molded product is a polyester film.