TW201333066A - Wholly aromatic polyester, polyester resin composition, and polyester molded article - Google Patents

Abstract

Provided is a wholly aromatic polyester which has excellent heat resistance and excellent toughness. This wholly aromatic polyester is composed of constituent units represented by general formulae (I), (II), (III), (IV) and (V). Relative to the total constituent units, the constituent unit of formula (I) is contained in an amount of 40-70% by mole, the constituent unit of formula (II) is contained in an amount of 7-14% by mole, the constituent unit of formula (III) is contained in an amount of 8-26.5% by mole, the constituent unit of formula (IV) is contained in an amount of 0-10% by mole, and the constituent unit of formula (V) is contained in an amount of 8-26.5% by mole, with the total content of the constituent unit of formula (II) and the constituent unit of formula (IV) being 12-17% by mole.

Description

Fully aromatic polyester, polyester resin composition, and polyester molded article

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

Commercially available wholly aromatic polyesters are based on 4-hydroxybenzoic acid. However, since the homopolymer of 4-hydroxybenzoic acid has a higher melting point than the decomposition point, it is required to copolymerize with various components to lower the melting point.

For example, a wholly aromatic polyester such as 1,4-phenylene dicarboxylic acid, 1,4-dihydroxybenzene or 4,4'-dihydroxybiphenyl is known as a copolymerization component. However, the melting point of the wholly aromatic polyester is 350 ° C or higher, and the melt processing by a general-purpose apparatus is too high.

Further, in order to lower the melting point of such a wholly aromatic polyester to a temperature at which a general-purpose melt processing machine can be used, various methods have been tried. However, on the other side which achieves a low melting point to some extent, there is a problem that the heat resistance of the wholly aromatic polyester represented by the mechanical strength at a high temperature (near the melting point) cannot be maintained.

In order to solve such problems, Patent Literatures 1 to 2 propose a copolymerized polyester in which 6-hydroxy-2-naphthoic acid, a diol component, and a dicarboxylic acid component are combined.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 59-62630

[Patent Document 2] JP-A-63-275628

However, the copolymerized polyester proposed in Patent Documents 1 to 2 has low toughness and has a problem that cracks occur in the molded article during molding.

The present invention has been made to solve the above problems and to provide a wholly aromatic polyester excellent in heat resistance and toughness.

The present inventors focused on repeated research to solve the above problems. As a result, it has been found that the wholly aromatic polyester has the constituent units represented by the following general formulae (I), (II), (III), (IV) and (V), and the constituent unit of (I) for the entire constituent unit. 40 to 70 mol%, (II) is 7-14 mol%, (III) is 8~26.5 mol%, and (IV) is 0-10 mol%, ( The constituent unit of V) is 8 to 26.5 mol%, and the total unit of the above (II) and the constituent unit of the above (IV) are 12 to 17 mol% in total, and the above problems can be solved to complete the present invention. More specifically, the present invention provides the following.

(1) A wholly aromatic polyester which exhibits optical anisotropy upon melting and which is characterized by the following general formulae (I), (II), (III), (IV) and (V) The constituent unit shown is an essential component. For the entire constituent unit, the constituent unit of (I) is 40 to 70 mol%, and the constituent unit of (II) is 7 to 14 mol%, and the composition of (III) The unit is 8~26.5 mol%, the constituent unit of (IV) is 0~10 mol%, and the constituent unit of (V) is 8~26.5 mol%, the constituent unit of the above (II) and the above (IV) The constituent units total 12 to 17 mol%.

(2) The wholly aromatic polyester according to (1), which comprises the above (IV) The unit is 1~8 mol%.

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

(4) The wholly aromatic polyester according to any one of (1) to (3), which has a melting point of 300 to 390 °C.

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

(6) A polyester resin composition in which 100 parts by mass of the wholly aromatic polyester according to any one of (1) to (4) is blended with an inorganic filler or an organic filler of 20 to 80 parts by mass. to make.

(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 article according to (7), wherein the polyester molded article is a heat-fixed connector, a CPU socket, a relay switch component, a bobbin, an actuator, a noise reduction filter box, or an OA machine. Roller.

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

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

According to the present invention, it is constituted by a specific constituent unit, exhibits optical anisotropy upon melting, the wholly aromatic polyester of the present invention, and contains the wholly aromatic The polyester resin composition of the group polyester is excellent in fluidity at the time of melting, and is excellent in heat resistance and toughness when the molded article is produced.

Further, since the total aromatic polyester or polyester resin composition of the present invention is not too high in the molding processing temperature, it can be injection molded or extrusion molded and compression molded without using a molding machine having a special structure.

As described above, the wholly aromatic polyester or polyester resin composition of the present invention has excellent moldability and can be molded by using various types of molding machines, and as a result, can be easily processed into various three-dimensional molded articles, fibers, films, and the like. . Therefore, a connector for a good use of the wholly aromatic polyester or polyester resin composition of the present invention, a CPU socket, a relay switch part, a bobbin, an actuator, a noise reduction filter box or an OA machine can be easily obtained. The molded article such as the fixed roller is heated.

Hereinafter, embodiments of the present invention will be described. Furthermore, the present invention is not limited to the following embodiments.

<all aromatic polyester>

The wholly aromatic polyester of the present invention is composed of the constituent units represented by the following general formulae (I), (II), (III), (IV) and (V).

The constituent unit represented by the formula (I) is 4-hydroxybenzoic acid (HBA). The wholly aromatic polyester of the present invention contains 40 to 70 mole % HBA for the total constituent unit. If the content of HBA is less than 40% by mole, or more than 70% by mole, the melting point of the wholly aromatic polyester will be significantly higher, depending on the situation, the wholly aromatic polyester will solidify in the reactor at the time of manufacture. It is not preferable to produce a polymer having a desired molecular weight.

The constituent unit represented by the formula (II) is 6-hydroxy-2-naphthoic acid (HNA). The wholly aromatic polyester of the present invention contains 7 to 14 mole % HNA for the total constituent unit. The content of HNA is less than 7 mol%, and the melting point will be remarkably high during the production of the wholly aromatic polyester, and depending on the case, the wholly aromatic polyester will be solidified in the reactor at the time of manufacture, and the desired production cannot be achieved. The molecular weight of the polymer is not good. Further, when the content of HNA exceeds 14 mol%, the heat resistance of the wholly aromatic polyester of the present invention becomes low.

a constituent unit represented by the formula (III), which is a 1,4-phenylene dicarboxylic acid (TA). The wholly aromatic polyester of the present invention contains 8 to 26.5 mol% of TA for the total constituent unit. If the content of TA is less than 8 mol%, or more than 26.5 mol%, the melting point of the wholly aromatic polyester will be significantly higher, depending on the case, the wholly aromatic polyester will solidify in the reactor at the time of manufacture. It is not preferable to produce a polymer having a desired molecular weight.

The constituent unit represented by the formula (IV) is 1,3-phenylene dicarboxylic acid (IA). The wholly aromatic polyester of the present invention contains 0 to 10 mol% of IA for the entire constituent unit. When the content of IA exceeds 10 mol%, the heat resistance of the wholly aromatic polyester becomes low.

The constituent unit represented by the formula (V) is 1,4-benzenediol (HQ). The wholly aromatic polyester of the present invention contains 8 to 26.5 mol% HQ for the total constituent unit. If the content of HQ is less than 8 mol%, or exceeds 26.5 mol%, the melting point of the wholly aromatic polyester will be significantly higher, and depending on the case, the wholly aromatic polyester will be solidified in the reactor at the time of manufacture. It is not preferable to produce a polymer having a desired molecular weight.

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%. When the total content is less than 12 mol%, the toughness of the polyester molded article obtained by the wholly aromatic polyester or the molded polyester resin composition of the present invention may be lowered. Further, when the total content exceeds 17 mol%, the heat resistance of the wholly aromatic polyester is lowered.

As described above, the wholly aromatic polyester of the present invention further contains the constituent unit of (II) and (IV) because each specific constituent unit (I) to (V) contains a specific amount for the entire constituent unit. The total content of the constituent units Since the predetermined range is adjusted, the toughness of the polyester molded article obtained by molding the wholly aromatic polyester of the present invention can be improved while having heat resistance.

As an index indicating the above-mentioned toughness, the heat of crystallization of the wholly aromatic polyester can be mentioned. When the heat of crystallization is 2.7 J/g or more, the above-mentioned toughness tends to be low, which is not preferable. The preferred value of the crystallization heat is 2.5 J/g or less, and more preferably 2.2 J/g or less. The heat of crystallization can be determined by differential calorimetry. Further, in the case of the polyester resin composition of the present invention to be described later, the heat of crystallization of the polyester resin composition is considered. The preferred range of the polyester resin composition is also the same.

Further, the wholly aromatic polyester of the present invention is excellent in moldability. The formability 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 of 10 to 40 ° C higher than the melting point is 1 × 10 ⁵ Pa. The following is better. At 5Pa. s above 1×10 ² Pa. s is better below. These melt viscosities are achieved by having liquid crystal properties to be described later. Further, in the case of the polyester resin composition of the present invention to be described later, the melt viscosity of the polyester resin composition is considered. The preferred range of the case of the polyester resin composition is also the same.

In addition, the wholly aromatic polyester of the present invention may contain constituent units other than the constituent units represented by the above (I) to (V) insofar as the effects of the present invention are not impaired. Further, as long as it is a trace amount, it may contain a constituent unit which does not have an aromatic group.

Next, a method for producing the wholly aromatic polyester of the present invention will be described. The wholly aromatic polyester of the present invention is polymerized by a direct polymerization method or a transesterification method. At the time of polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, or the like may be used. Solid phase polymerization method, etc.

In the present invention, at the time of polymerization, a monomer which is activated by a deuterating agent for a polymerizable monomer or an acid chloride derivative may be used. The oximation agent may be an acid anhydride such as anhydrous acetic acid.

Various catalysts can be used for the polymerization, and representative examples thereof include dialkyl tin oxides, diaryl tin oxides, titanium oxides, alkoxy titanium silicates, alkoxy titanium compounds, and carboxylic acids. Alkali and alkaline earth metal salts, such as Lewis acid salts of BF ₃ , and the like. The amount of the catalyst used is generally about 0.001 to 1% by mass based on the total mass of the monomer, and particularly preferably 0.003 to 0.2% by mass.

Further, when solution polymerization or slurry polymerization is carried out, the solvent is a liquid paraffin, a highly heat-resistant synthetic oil, an inert mineral oil or the like.

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

In the reaction, the whole raw material monomer, the oximation agent and the catalyst can be put into the same reaction vessel to start the reaction (one-stage formula), and the hydroxyl groups of the raw material monomers (I), (II) and (V) can also be used as the oximation agent. After deuteration, it reacts with the carboxyl groups of (III) and (IV) (two-stage formula).

The melt polymerization is carried out after the pressure in the reaction system reaches a predetermined temperature and starts to be reduced to a predetermined degree of pressure reduction. After the torque of the stirrer reaches a predetermined value, an inert gas is introduced, and the pressure is reduced to a predetermined pressurized state by a normal pressure in a reduced pressure state, and the wholly aromatic polyester is discharged from the reaction system.

The wholly aromatic polyester produced by the above polymerization method can increase the molecular weight by solid phase polymerization which is heated in an inert gas under normal pressure or reduced pressure. The preferred conditions for the solid phase polymerization are reaction temperatures of 230 to 350 ° C, preferably 260 to 330 ° C, and finally reach a 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 upon melting. The optical anisotropic property at the time of melting shows the wholly aromatic polyester liquid crystalline polymer of the present invention.

In the present invention, the wholly aromatic polyester is a liquid crystalline polymer, and the wholly aromatic polyester is an indispensable element for both thermal stability and ease of processing. The wholly aromatic polyester composed of the above-mentioned constituent units (I) to (V) may have no anisotropic melt phase depending on the constituent components and the sequence distribution in the polymer, but the polymer of the present invention is limited to melting. An all-aromatic polyester exhibiting optical anisotropy.

The nature of the melting anisotropy can be confirmed by a conventional polarizing inspection method using a crossed polarizer. More specifically, the confirmation of the melting anisotropy was carried out by using a polarizing microscope manufactured by Olympus Co., Ltd., and the sample placed on a heating table manufactured by LINKAM Co., Ltd. was observed under a nitrogen atmosphere at a magnification of 150 times. The liquid crystalline polymer is optically anisotropic, and light is transmitted when inserted between the orthogonal polarizers. The sample is optically anisotropic, and for example, it can penetrate polarized light in a molten stationary state.

Since the viscosity of the nematic liquid crystalline polymer is remarkably lowered at a melting point or higher, liquid crystallinity is generally exhibited as an index of workability at a temperature of a melting point or higher. The melting point (liquid crystal display temperature), the higher the heat resistance, the better. However, considering the heat deterioration during the melt processing of the polymer or the heating ability of the molding machine, 300 to 390 ° C is preferable. Further, it is more preferably 380 ° C or lower.

<Polyester Resin Composition>

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

The inorganic filler to be blended in the polyester resin composition of the present invention has a fibrous form, a granular form, and a plate shape.

Fibrous inorganic fillers, which can be glass fiber, asbestos fiber, cerium oxide fiber, cerium oxide. Alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, tantalum nitride fiber, boron fiber, potassium titanate fiber, fiber such as ettringite citrate, magnesium sulfate fiber, aluminum borate fiber, and An inorganic fibrous material such as a fibrous material of a metal such as stainless steel, aluminum, titanium, copper or brass. In particular, a representative fibrous filler is a glass fiber.

Further, the powdery inorganic filler may be carbon black, graphite, cerium oxide, quartz powder, glass beads, ground glass fiber, glass ball, glass powder, calcium silicate, aluminum silicate, kaolin, clay, algae Soil, such as strontium silicate, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide, aluminum oxide, carbonates of metals such as calcium carbonate, magnesium carbonate, such as calcium sulfate, Metal sulfate such as barium sulfate, other ferrites, tantalum carbide, tantalum nitride, boron nitride, various metal powders, and the like.

Further, the plate-like inorganic filler may, for example, be mica, glass flakes, talc, various metal foils or the like.

Examples of organic fillers include aromatic polyester fibers and liquid crystallinity. A heat-resistant high-strength synthetic fiber such as a polymer fiber, an aromatic polyamide or a polyimide fiber.

These inorganic and organic fillers may be used alone or in combination of two or more. The fibrous inorganic filler is preferably used in combination with a granular or plate-shaped inorganic filler in combination with mechanical strength, dimensional accuracy, electrical properties and the like. It is particularly preferable that the fibrous filler is made of glass fiber or a plate-like filler of mica and talc, and the blending amount is preferably 120 parts by mass or less per 100 parts by mass of the wholly aromatic polyester, and preferably 20 to 80 parts by mass. Further, the fiber length of the glass fiber is preferably 200 μm or more. By combining such glass fibers with mica and talc, the polyester resin composition is particularly remarkable for the improvement of heat distortion temperature, mechanical properties, and the like.

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

The polyester resin composition of the present invention contains the wholly aromatic polyester, inorganic or organic filler of the present invention as an essential component as described above, and may contain other components insofar as the effects of the present invention are not impaired. Ingredients. Here, the other components may be any component, and examples thereof include additives such as other resins, oxidation inhibitors, stabilizers, pigments, and crystal nucleating agents.

Further, the method for producing the polyester resin composition of the present invention is not particularly limited, and the polyester resin composition can be prepared by a conventional method.

<Polyester molded product>

The polyester molded article of the present invention is 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 employed. A general forming method can be exemplified by injection molding. A method of extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, and the like.

The polyester molded article obtained by molding the wholly aromatic polyester of the present invention is excellent in heat resistance and toughness. Further, the polyester molded article obtained by molding the polyester resin composition of the present invention has excellent heat resistance and toughness, and contains an inorganic or organic filler, thereby further improving mechanical strength and the like.

Further, the wholly aromatic polyester or polyester resin composition of the present invention is excellent in moldability, and a polyester molded article having a desired shape can be easily obtained.

Preferred uses of the polyester molded article of the present invention having the properties as described above include a connector, a CPU socket, a relay switch component, a bobbin, an actuator, a noise reduction filter box, or a heating fixed roller of an OA machine. Round and so on.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited to the following examples.

<Example 1>

In a polymerization vessel equipped with a stirrer, a reflux pipe, a monomer inlet, a nitrogen inlet, and a pressure reduction/outflow line, the following raw material monomers, a metal catalyst, and a halogenating agent were placed, and nitrogen substitution was started.

(I) 4-hydroxybenzoic acid 136 g (41 mol%) (HBA)

(II) 6-hydroxy-2-naphthoic acid 41g (9mol%) (HNA)

(III) Terephthalic acid 71g (17.7 mol%) (TA)

(IV) 30 g of isophthalic acid (7.5 mol%) (IA)

(V) 1,4-phenylene glycol 66g (24.8 mol%) (HQ)

Potassium acetate catalyst 15mg

Anhydrous acetic acid 252g

After the raw material was placed, the temperature of the reaction system was raised to 140 ° C, and the reaction was carried out at 140 ° C for 1 hour. Thereafter, the temperature was further increased to 360 ° C for 5.5 hours, and the pressure was reduced to 10 Torr (that is, 1330 Pa) over 20 minutes, and acetic acid, excess anhydrous acetic acid, and other low boiling fraction were distilled and melt-polymerized. After the stirring torque reaches a predetermined value, the introduced nitrogen is often pressed to a pressurized state from a reduced pressure state, and the polymer is discharged from the lower portion of the polymerization vessel.

<evaluation>

With respect to the wholly aromatic polyester of Example 1, the melting point, the crystallization temperature, the crystallization heat, the melt viscosity, and the softening temperature were evaluated by the following methods. The results are shown in Table 1.

[melting point]

The polymer was observed by a DSC manufactured by Perkin Elmere Co., Ltd., and the polymer was observed at room temperature at a temperature rising condition of 20 ° C /min. After the endothermic peak temperature (Tml) was observed, the temperature was maintained at (Tml + 40) ° C for 2 minutes. After cooling to room temperature under a cooling condition of 20 ° C /min, the temperature of the observed endothermic peak when measured at a temperature rising condition of 20 ° C /min was measured again.

[crystallization temperature]

The polymer was observed by a DSC manufactured by Perkin Elmer Co., Ltd., and the polymer was observed at room temperature at a temperature rising condition of 20 ° C /min. After the endothermic peak temperature (Tml) was observed, the temperature was maintained at (Tml + 40) ° C for 2 minutes. The temperature of the observed exothermic peak when measured under a temperature drop condition of 20 ° C /min was measured.

[crystallization heat]

Using a DSC made by Perkin Elmer, the polymer was made from room temperature to 20 When the temperature rise condition of °C/min was measured, it was observed at a temperature of (Tml+40) °C after the endothermic peak temperature (Tml) was observed for 2 minutes, and then measured at a temperature drop condition of 20 ° C/min. The heat of the heat peak obtained by the fever peak.

[melt viscosity]

A tube hole having an inner diameter of 1 mm and a length of 20 mm was used at a temperature higher by 10 to 20 ° C than the melting point, and the melt viscosity at a shear rate of 1000 sec ^{-1 was} calculated by a Toyo Seiki capillary rheometer.

[softening temperature]

The prepared polyester was formed into a disk having a thickness of 1 mm by a hot press, and a fixed load of 12.7 MPa was applied to the molded product, and the temperature was raised at 20 ° C /min on a heating plate, and a needle having a diameter of 1 mm was applied to reach the thickness of the molded article. The temperature at 5% is taken as the softening temperature.

<Examples 2 to 8 and Comparative Examples 1 to 8>

The polymer was obtained in the same manner as in Example 1 except that the types and the ratios of the raw material monomers (% by mole) were as shown in Tables 1 and 2. Further, the same evaluation as in Example 1 was carried out. The results of the evaluation are also shown in Tables 1 and 2. Further, in Comparative Examples 1, 2, and 4, since the polymer was solidified in the reactor at the time of production, a polymer having a desired molecular weight (indicated as NG in the table) could not be produced.

<Examples 9 to 10, Comparative Examples 9 to 10>

Example 9, using the wholly aromatic polyester of Example 6, with glass Fiber: Japan Electric Glass Co., Ltd. ECS03T-786H, fiber diameter 10μm, length 3mm cut strand, and mica: (share) Yamaguchi mica industrial AB-25S, average particle size 25μm, according to the formula shown in Table 3 The content of 100 parts by mass of the wholly aromatic polyester was blended and kneaded by a twin-screw extruder (TEX 30 α manufactured by Nippon Steel Co., Ltd.) to obtain a wholly aromatic polyester composition having a colloidal shape. After drying the wholly aromatic polyester composition at 140 ° C for 3 hours, the molded article shown in Fig. 1 was injection-molded by the injection molding machine under the following molding conditions, and the moldability was good, and cracking of the molded product did not occur. Shows good toughness characteristics. The results are shown in Table 3. Further, the injection molded article for evaluation shown in Fig. 1 has a peripheral diameter of 23.6 mm, and has 31 holes of φ 3.2 mm inside, and the minimum thickness of the distance between the holes is 0.16 mm. The gate is shown by the arrow shown in Figure 1 (3 o'clock gate). In the observation of the crack of the molded article, the occurrence of the crack around the hole was observed at a magnification of 5 times using a solid microscope, and "×" was observed when the molded product was cracked, and it was judged as "○" when it did not occur. Further, Fig. 1(b) shows the size of the injection molded article for evaluation using the examples. Fig. 1(b) shows only one hole for explaining the dimension, but actually, 31 holes are formed on the surface of φ 22.2 mm.

(forming conditions)

Forming Machine: Sumitomo Heavy Machinery Industry SE30DUZ

Tube temperature: (nozzle) 350 ° C - 355 ° C - 340 ° C - 330 ° C (Example 9)

Mold temperature: 140 ° C

Injection speed: 50mm/min

Pressure: 100MPa

Holding time: 2sec

Cooling time: 10sec

Screw rotation number: 120rpm

Screw back pressure: 1.2MPa

In Example 10, using the wholly aromatic polyester of Example 5, the glass fiber and the mica were used in the same manner as in Example 9, and the formulation shown in Table 3 was used as a twin-screw extruder (TEX 30 α manufactured by Nippon Steel Co., Ltd.). The blending was carried out to obtain a wholly aromatic polyester composition in the form of a colloidal particle. After the whole aromatic polyester composition was dried at 140 ° C for 3 hours, it was injection molded under the same conditions as in Example 9 using an injection molding machine. As a result, the moldability was good, and the molded product was not cracked and showed good results. Toughness characteristics. The results are shown in Table 3. Further, among the molding conditions, only the condition of the cylinder temperature was changed to 360 ° C - 365 ° C - 350 ° C - 340 ° C.

In Comparative Example 9, the wholly aromatic polyester of Comparative Example 6 was used, and in the same manner as in Example 9, glass fiber and mica were used, and the formulation shown in Table 3 was used as a twin-screw extruder (TEX 30 α manufactured by Nippon Steel Co., Ltd.). After the kneading was carried out to obtain a wholly aromatic polyester composition having a colloidal shape, the molding toughness (crack of the molded article) was evaluated by injection molding under the same conditions as in Example 9. The results of these are shown in Table 3. Further, under the molding conditions, only the cylinder temperature condition is changed to 390 ° C - 395 ° C - 380 ° C - 370 ° C.

In Comparative Example 10, the wholly aromatic polyester of Comparative Example 8 was used, and in the same manner as in Example 9, glass fiber and mica were used, and the formulation shown in Table 3 was used as a twin-screw extruder (TEX 30 α manufactured by Nippon Steel Co., Ltd.). After blending and kneading to obtain a wholly aromatic polyester composition having a colloidal shape, the same strip as in Example 9 was obtained. The injection molding was used to evaluate the toughness (crack of the molded article). The results of these are shown in Table 3. Further, under the molding conditions, only the cylinder temperature condition is changed to 380 ° C - 385 ° C - 370 ° C - 360 ° C.

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

Fig. 1 is a schematic view showing a molded article produced in Examples 9 and 10 and Comparative Examples 9 and 10, wherein (a) is a plan view and (b) is a view showing the dimensions thereof. Furthermore, the unit of the numerical value in the figure is mm.

Claims (10)

A wholly aromatic polyester exhibiting optical anisotropy upon melting, and is characterized by the constituent units represented by the following general formulae (I), (II), (III), (IV) and (V) It must be composed of components. For the total constituent units: (I) is 40~70 mol%, (II) is 7~14 mol%, and (III) is 8~26.5 mol%. The constituent unit of (IV) is 0 to 10 mol%, and the constituent unit of (V) is 8 to 26.5 mol%, and the constituent unit of the above (II) and the constituent unit of the above (IV) are 12 to 17 mo ear%: The wholly aromatic polyester according to claim 1, wherein the constituent unit of the above (IV) is 1 to 8 mol%. The wholly aromatic polyester according to claim 1 or 2, wherein the melt viscosity at a shear rate of 1000 sec ^-1 is 1 × 10 ⁵ at a temperature higher than a melting point of the wholly aromatic polyester by 10 to 40 ° C. Pa. s below. The wholly aromatic polyester according to any one of claims 1 to 3, which has a melting point of 300 to 390 °C. A polyester resin composition obtained by blending 120 parts by mass or less of an inorganic filler or an organic filler with 100 parts by mass of the wholly aromatic polyester according to any one of claims 1 to 4. A polyester resin composition obtained by blending an inorganic filler or an organic filler in an amount of 20 to 80 parts by mass of 100 parts by mass of the wholly aromatic polyester according to any one of claims 1 to 4. A polyester molded article obtained by molding the wholly aromatic polyester according to any one of claims 1 to 4 or the polyester resin composition according to claim 5 or 6. The polyester molded article according to claim 7, wherein the polyester molded article is heated by a connector, a CPU socket, a relay switch component, a bobbin, an actuator, a noise reduction filter box, or an OA machine. Roller. The polyester molded article according to claim 7, wherein the polyester molded article is a polyester fiber. The polyester molded article according to claim 7, wherein the polyester molded article is a polyester film.