JP3440137B2 - Wholly aromatic polyester and composition thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic material composed of a novel wholly aromatic polyester, having a high elastic modulus, and having excellent fluidity and heat resistance. More specifically, it relates to a heat-resistant organic material which is a polymer having a specific monomer composition and has a high elastic modulus due to orientation of molecular chains in the flow direction under a fluidized state.

[0002]

2. Description of the Related Art A wholly aromatic polyester has excellent properties based on its structure, but is most excellent among all resins in terms of heat resistance. In particular, wholly aromatic polyesters obtained from terephthalic acid, isophthalic acid, p-hydroxybenzoic acid or its derivative, and biphenyl-4,4'-diol (4,4'-biphenol) or its derivative are injection-molded. It is possible and has excellent physical properties, especially mechanical properties and electrical properties, and also has many of the required properties in the field of use of plastics, such as high heat resistance, chemical resistance, oil resistance, radiation resistance, and dimensional stability. It is known to be a resin.

[0003]

As described above, the wholly aromatic polyester has excellent heat resistance, but on the other hand, it has been pointed out that moldability is poor. For example, it is pointed out that an oven blister is likely to occur in, for example, an injection-molded article as a drawback. In general, as a method of improving moldability, a method of copolymerizing a non-linear monomer such as isophthalic acid or 6-hydroxy-2-naphthoic acid, or a monomer having a flexible chain such as ethylene glycol. A method of lowering the melting point by lowering the linearity or rigidity of the polymer has heretofore been carried out by a method, a method of copolymerizing a monomer having a bulky substituent such as chlorohydroquinone, phenylhydroquinone, or the like. However, in these methods, the improvement of the moldability is due only to the lowering of the melting point, so that the heat resistance, particularly the heat deformation temperature, is remarkably lowered as compared with the lowering of the melting point, and the moldability and the heat resistance can be balanced. It's extremely difficult. Therefore, a wholly aromatic polyester having good flowability and excellent balance of molding processability, heat resistance and blister resistance has long been desired.

Furthermore, in a copolyester prepared by copolymerizing a hydroxycarboxylic acid such as hydroxybenzoic acid, the sequence of structural units derived from the hydroxycarboxylic acid may differ depending on the production conditions. That is, depending on the production conditions, structural units derived from hydroxycarboxylic acid are introduced into the copolyester in blocks or randomly. It is easily expected that the physical properties of the obtained copolyester may change in response to such structural changes. However,
At present, it has not been sufficiently clarified what kind of sequence property of the copolyester affects the physical properties such as fluidity, molding processability, heat resistance, and blister resistance. In addition to the sequence properties of hydroxycarboxylic acids, in copolyesters in which a plurality of acids and diols are used in combination, structural factors such as the arrangement of the plurality of acids and diols may also affect the physical properties of the copolyester. However, the influence of such structural factors on the physical properties has not been sufficiently clarified as well.

[0005]

[Means for Solving the Problems] Therefore, the inventors of the present invention conducted various studies to synthesize various polyesters having optical melt anisotropy and aim to further improve the moldability and heat resistance of structural materials. As a result, the present invention has been completed. That is, the first aspect of the present invention relates to an aromatic polyester having optical melt anisotropy, which is characterized by comprising structural units represented by the following formulas (1) to (6).

[0006]

[Chemical 2]

(Where k, l, m, n, o and p are:
The content ratio (mol%) of each structural unit in the polyester is shown. 20 <k ≤ 80, l + m and n + o + p are substantially equal, 0 ≤ o ≤ 10, 1 ≤ p ≤ 7, 0 ≤ m ≤ (l + m) /
Have a relationship of 2. ) A second aspect of the present invention relates to an aromatic polyester comprising the structural unit described in the first aspect of the present invention and satisfying the relationship of the following formula. Tv-Tm <+ 10 ° C [where Tm is a melting point (Tm, ° C) measured by a differential scanning calorimeter (DSC), and Tv is a temperature (apparent temperature at which an apparent viscosity change sharply decreases with temperature). Viscosity stabilization start temperature, ° C) is a value measured by a capillary rheometer. The third aspect of the present invention relates to a polyester resin composition obtained by blending the above-mentioned aromatic polyester having optical melt anisotropy with an inorganic filler in an amount of 95% by weight or less (composition).

The present invention will be further described below. In the polyester of the present invention, for example, the structural unit represented by the formula (1) of Chemical formula 2 is p-hydroxybenzoic acid (HBA),
The constitutional unit represented by the formula (2) is 4,4′-biphenol (B
P), the constitutional unit represented by the formula (3) is hydroquinone (HQ), the constitutional unit represented by the formula (4) is terephthalic acid (TPA), and the constitutional unit represented by the formula (5) is The constitutional unit represented by the formula (6) is derived from isophthalic acid (IPA) from 4,4′-biphenyldicarboxylic acid (BP-DC). K, 1, m, n, o, and p, which represent the content ratio (mol%) of the above structural units (1) to (6) in the polyester, satisfy the relationship of the following formula. I) 20 <k ≦ 80 II) 1 + m and n + o + p are substantially equal. III) 0 ≦ o ≦ 10 IV) 1 ≦ p ≦ 7, preferably 1 ≦ p <4 V) 0 ≦ m ≦ (l + m) / 2, preferably 0.5 ≦ m ≦
(l + m) / 2.

Here, the constitutional unit of the formula (1) is essential,
When the content ratio k exceeds 80 mol%, the crystalline melting point of the obtained polyester becomes higher than the thermal decomposition temperature of the polymer and molding becomes impossible, which is not preferable. Also, k is 20
If it is less than mol%, it becomes difficult to form crystals of the polyester chain, so that the elastic modulus of the molded product using this is small and the heat resistance is also poor, which is not preferable.

The constitutional unit represented by the formula (6) is also essential in the present invention, and the use of the constitutional unit exhibits the effect of improving the fluidity of the polyester. Moreover, this effect is achieved only by copolymerizing a small amount. When the content ratio p of the structural unit of the formula (6) exceeds 7 mol%, it becomes difficult to produce a polyester by a usual melt polycondensation method, and in order to obtain a polymer having a sufficient degree of polymerization, It is necessary to lengthen the polymerization time as compared with the case where the constitutional unit of the formula is not added. Therefore, the polymer is markedly colored during polymerization, which is not practically preferable. In addition, it is also not preferable that the economical efficiency of polymer production is lowered due to the increase of the polymerization time. Further, if the content ratio is less than 1 mol%, the effect of copolymerization of improving the fluidity by the structural unit of the formula (6) cannot be obtained as described above, which is not preferable. The more preferable content of p is 1 ≦ p <4.

The constitutional unit of the formula (5) is a preferable constitutional component for improving the moldability of the obtained polyester, but when the content ratio o exceeds 10 mol%, the heat distortion temperature is remarkably lowered. Not preferable. Further, the structural unit of the formula (3) is a preferable component for improving heat resistance,
The content ratio m is less than 1 and is more than 1 because moldability is deteriorated, which is not preferable. Further, 0.5 ≦ m ≦ (l + m) / 2 is more preferable. Also, l + m
And n + o + p are substantially equal. That is, the sum of the content ratios (mol%) of the constitutional units of the formula (2) and the constitutional unit of the formula (3) is the content ratios (moles) of the constitutional units of the formulas (4), (5) and (6). %) Is substantially equal to the sum of.

The aromatic polyester of the present invention further satisfies the following formula. Tv −Tm <+ 10 ° C. Here, Tm is a melting point (° C.) measured by DSC, and Tv is a temperature (apparent viscosity stability start temperature, ° C.) at which a change in apparent viscosity at a temperature rise sharply decreases. It is a value measured by a capillary rheometer. An aromatic polyester having a value (Tv-Tm) obtained by subtracting the value of Tm from the value of Tv is less than + 10 ° C has high heat resistance, particularly high blister resistance. Note that this value may be a negative value. However, the temperature is usually set to -80 ° C, preferably to the negative side of -50 ° C. On the other hand, an aromatic polyester having a value obtained by subtracting the value of Tm from the value of Tv (Tv-Tm) of not less than + 10 ° C. is not preferable because it has low heat resistance, particularly low blister resistance. The specific measuring method of Tv and Tm will be described later.

The aromatic polyester of the present invention can be produced according to a conventional polyester polycondensation method, and the production method is not particularly limited, but a typical production method is as follows.
For example, the following methods (1) to (4) may be mentioned. (1) A method of producing from a diacylated aromatic dihydroxy compound, an acylated aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid such as terephthalic acid or 4,4′-biphenyldicarboxylic acid by a deacetic acid polycondensation reaction . (2) A method of producing from an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid such as terephthalic acid, 4,4′-biphenyldicarboxylic acid and acetic anhydride by a deacetic acid polycondensation reaction. (3) Aromatic dihydroxy compound and terephthalic acid, 4,
A method for producing from a diphenyl ester with an aromatic dicarboxylic acid such as 4′-biphenyldicarboxylic acid and a phenyl ester of an aromatic hydroxycarboxylic acid by dephenol polycondensation. (4) An aromatic dicarboxylic acid such as aromatic hydroxycarboxylic acid and terephthalic acid, 4,4′-biphenyldicarboxylic acid is reacted with a desired amount of diphenyl carbonate to form a phenyl ester of a carboxyl group, and then an aromatic dihydroxy compound is added. In addition, a method of producing by dephenol polycondensation reaction.

For example, p-hydroxybenzoic acid (HB
A) 4,4'-biphenol (BP), terephthalic acid (TPA), 4,4'-biphenyldicarboxylic acid (BP-
DC) and hydroquinone (HQ) were charged to the reactor,
Acetic anhydride was added to perform acetylation under reflux of acetic anhydride,
Then, the temperature is raised to carry out deacetic acid polycondensation while distilling off acetic acid in the temperature range of 250 to 350 ° C. to obtain a polyester. The polymerization time can be selected in the range of 1 hour to several tens of hours.

Typical catalysts used in the polycondensation reaction are stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide, and metal catalysts, especially in the case of dephenol polycondensation. Is effective for.

Further, regarding each of the above melt polycondensation methods,
It is also possible to use melt polymerization and solid phase polymerization together. That is, it is possible to increase the degree of polymerization of a polymer which has been polycondensed by melt polymerization by solid phase polymerization. For the solid phase polymerization, widely known methods can be used. For example, a polyester obtained by melt polymerization is heated in an inert atmosphere such as nitrogen at a temperature range of 250 to 350 ° C. for 1 hour to 10 hours.
It is performed by heating for a time.

Further, the polymerization vessel is not particularly limited, but stirring equipment generally used for high-viscosity reaction, for example, anchor type agitator, multi-stage agitator, spiral zone agitator, spiral shaft agitator, etc. , A stirring bowl type polymerizer equipped with a modified stirrer, and further selected from a Warner mixer, a Banbury mixer, a pony mixer, a Mueller mixer, a roll mill, a continuously operable cokneader, a hug mill, a gear compounder, etc. Things are desirable.

In the polyester of the present invention, in addition to the monomer containing each of the above structural units, 2,6-dicarboxynaphthalene, 2,5-dicarboxynaphthalene, 3,4 '
-Aromatic dicarboxylic acids such as biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, resorcin, catechol, aromatic diols such as 2,6-dihydroxynaphthalene, 2,5-dihydroxynaphthalene and m-hydroxybenzoic acid, 6 -Other aromatic oxycarboxylic acids such as hydroxy-2-naphthoic acid, p-aminophenol,
p-Aminobenzoic acid and the like can be further copolymerized within a range that does not impair the effects of the present invention.

Conventionally, the melting point of polyester has been determined by measuring the endothermic peak by DSC. Specifically, the heat history of the polyester resin to be measured is removed by an appropriate method, then the temperature is raised by DSC, and the temperature corresponding to the position of the endothermic peak that appears in the process is taken as the melting point of the target resin. . The melting point measured by this method was used as a standard for the molding temperature of the target resin.
For example, if this melting point is high, a high molding temperature is required. When molding is performed at a temperature lower than this molding temperature, inconveniences such as instable molding operation and failure to obtain a molded product of a desired size occur, and in extreme cases, molding becomes impossible. Sometimes. Further, in the case of a polyester exhibiting optical melt anisotropy, the molding temperature is generally the thermal decomposition temperature of the polyester (since this is a value due to the interatomic bond energy, it depends on the type of the polyester. It is a value that does not change much.) Therefore, in order to avoid thermal decomposition in an extreme case, a material having a low molding temperature has been required.

However, in the case of polyester exhibiting optical melt anisotropy, it was found that the melting point measured by DSC as described above is unsuitable as a measure of the molding temperature. That is, the apparent viscosity of the polyester having optical melt anisotropy shows a sharp decrease with temperature increase in a temperature range below a specific temperature with respect to a temperature increase due to heating, but in a temperature range exceeding the specific temperature. It was confirmed that the change in apparent viscosity with respect to temperature was much smaller than that in the lower temperature range. Moreover, the specific temperature exhibiting such a change is usually considerably higher than the melting point measured by the above-mentioned DSC. The specific temperature at which such a change in apparent viscosity with respect to temperature becomes small is hereinafter referred to as “apparent viscosity stabilization start temperature”. When the temperature exceeds the apparent viscosity stability onset temperature, the change in viscosity becomes small. Therefore, it is appropriate to perform molding in such a temperature range. In the case of polyester exhibiting optical melt anisotropy, "apparent viscosity" The "stabilization start temperature" can be used as a guide for the molding temperature. That is, the polyester having a low temperature can be molded at a low temperature.

The polyester of the present invention has a high melting point measured by DSC, a high heat distortion temperature, a high blister resistance (a temperature at which blisters occur), and the like, but has a lower molding temperature than conventionally known polyesters. It has characteristics. The aromatic polyester of the present invention can be produced by appropriately combining the composition ratios of the above-mentioned components and conventionally known polymerization conditions, etc., but all of them are polymerized so as to obtain one having the above physical properties. .

The polyester of the present invention obtained as described above may be appropriately blended with various fibrous, powdery or plate-like inorganic and organic fillers mainly for improving the mechanical strength. it can. Examples of the fibrous filler include inorganic fibrous substances such as glass fibers, asbestos fibers, silica fibers, silica-alumina fibers, potassium titanate fibers, and fibrous substances of metals such as aluminum titanium and copper. Particularly representative is glass fiber. on the other hand,
Examples of granular fillers include carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber, glass balloons, glass powder, calcium silicate, aluminum silicate, talc, clay, diatomaceous earth, and wollastonite. Examples thereof include various silicates, iron oxides, titanium oxides, zinc oxides, metal oxides such as antimony trioxide, alumina and various other metal powders. Examples of the plate-shaped filler include mica, glass flakes, various metal foils and the like. Other examples of organic fillers include:
It is a heat-resistant high-strength synthetic fiber such as aromatic polyester, aromatic polyamide, or polyimide fiber. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary.

In addition to the above, conventionally known antioxidants,
Various additives such as heat stabilizers, extenders, reinforcing agents, pigments and flame retardants may be added in appropriate amounts. These additives and fillers can be used alone or in combination of two or more.

When an inorganic filler is used, its content is 95% by weight or less, preferably 80% by weight, based on the whole composition.
It is the following. Incorporation of an inorganic filler in an amount of more than 95% by weight is not preferable because the mechanical strength is rather lowered.

Further, the thermoplastic resin of the present invention may be appropriately blended with other thermoplastic resins as long as the object of the present invention is not impaired.

The wholly aromatic polyester of the present invention obtained as described above can be used in a conventionally known molding method, for example, melt molding such as extrusion molding, injection molding, compression molding and blow molding, by utilizing its excellent characteristics. By providing it, it is possible to process it into a molded product such as a fiber, a film, a three-dimensional molded product, a container or a hose. Examples of such concrete molded products include the following. That is,
Electric parts include hair dryer parts (housing etc.), washing machine parts (bearings, valves, cocks, rotors etc.), video parts (brake rings etc.), dishwasher parts, coffee server parts (housing etc.), tape recorder parts. (Bearings, etc.), clothes dryer parts (pins, etc.), electromagnetic induction range parts (sensor cases, etc.), motor parts (commutator, brush holder, coreless motor parts, etc.), lamp holders (floodlight socket, halogen lamp) Sockets, etc.), potentiometers (coil formers, etc.), soldering iron parts, casserole bases, record player parts (tone arm bearings, etc.); in electronic parts, relay parts (housings, arc insulators, etc.), printed circuit boards, switches (Houjin Etc.), connectors, bobbins, electronic watch parts (housing, stator trimmer capacitor, an insulating material), level switch parts,
Electronic exchange parts (microwave absorption parts, bobbins, etc.),
IC manufacturing equipment parts (IC sockets, wafer baskets, sleeves, etc.), ultrasonic flaw detector parts (sensors, etc.), electronic tube parts (insulation rings, etc.), electronic parts holders, internal cylinder pressure measuring device parts (ring element insulation, etc.) ), Battery parts (catalyst holders, etc.), resistors, hearing aid parts, surface thermometer parts (couple parts, etc.), fuse parts (housing etc.); As automotive parts, EGR valves (valve body, valve cover,
Valves, etc.), piston rings, apex seals, plug insulation, shock absorber parts (rings, bearings, etc.), bulldozer parts (piston rings, bearings, etc.), distributor parts (cams, housings, etc.), ignition switch parts (housings, etc.) , Brake parts (Brake material binders, brakes, bleeders, etc.), Exhaust gas pipe parts (Sleeves, etc.), Exhaust gas temperature sensors (Housings, etc.), Wire cables, Lamp parts (Headlamp reflectors, etc.), Automotive coolers; Sliding Materials and machine parts include copier parts (separation claws, bearings, hot roll coating, etc.), computer parts (non-wear rings, etc.), line printer parts (guides, backup burring, etc.), compressors, etc. Parts (piston rings, brakes, etc.), soy sauce manufacturing equipment sliding materials, papermaking dryer parts, spinning machine parts (spindle, pulley, crimper guides, etc.), projector parts, vending machine parts (bearings, etc.), glass manufacturing Jig, cathode ray tube manufacturing jig, electric wire manufacturing jig, can making machine jig, bottle manufacturing device jig (feeding claws, etc.), stern bearing, oilless bearing (oil-impregnated bearing,
Three-layer bearings, submersible bearings, heat-resistant bearings for aseptic factories, rolling bearings (race rings, etc.), packing, conveyor belts, mechanical seals, pulleys, air pumps (rotors, etc.), linear compressors (pistons, etc.), lock parts, Reflow solder parts, welding guide pins, liquid chromatograph switching valves, crude oil mining pump parts, pipe flange insulation, heating piping parts (insulating washers, etc.), extruder parts (dies, etc.), camera bodies, gas Calorie meter parts (housing etc.), sewing machine parts (cam etc.), lighter parts (housing etc.), dial gauge parts, insulation material for refrigerator stator, air conditioner parts (muffler etc.),
Robot parts, oven bearings, gasoline filters; other synchrotron parts, TLD parts (caps, etc.), abradable seals, grinding wheel binders, simple molds, heat-resistant fiber aircraft in-flight tableware, skis, etc.

The molded article obtained from the wholly aromatic polyester of the present invention has optical anisotropy and good fluidity due to its molecular arrangement, and has extremely excellent mechanical properties and heat resistance. The strength of the molded product thus obtained can be increased by heat treatment, and the elastic modulus can be increased in many cases. This heat treatment is performed on the molded product under an inert atmosphere (for example, in nitrogen, argon, helium, or steam) and under an oxygen-containing atmosphere (for example, in air).
Alternatively, it can be performed by heat treatment under reduced pressure at a temperature not higher than the melting point of the polymer.

[0028]

The present invention will be described in more detail with reference to the following examples. <Measurement method> The physical properties shown in the examples of the present invention were measured by the following methods. As the molding temperature, the apparent viscosity stabilization start temperature determined by the following method was used. (Melting point): DSC device (Seiko Denshi Kogyo KK, SS
C-5020) was used. First, in a nitrogen atmosphere, the heat history of the sample is removed by raising the temperature at a rate of 20 ° C./min until the endothermic peak development ends, and then the temperature is lowered at a rate of 10 ° C./min and cooled to room temperature. To do. Then again, 20
The temperature is raised at a rate of ° C / min, and the temperature corresponding to the position of the endothermic peak developed at this time is taken as the melting point (Tm, ° C). (Apparent viscosity stable onset temperature): L / D by a capillary rheometer (manufactured by Intesco Corporation, model 2010)
= 40/1 (mm / mm) and 90 ° inflow angle, the temperature dependence of the apparent viscosity at a shear rate of 100 sec ⁻¹ was determined using the capillary.
v, ° C). That is, the temperature dependence (gradient with respect to temperature) of the apparent viscosity is measured by heating at a constant rate of 4 ° C./min from a temperature lower by 50 ° C. than the melting point (Tm) measured in advance by the above-mentioned measurement method, and measuring the apparent viscosity. The temperature at which the temperature dependence sharply decreases is determined. In the apparent viscosity-temperature curve obtained here, the curve is relatively close to a straight line in the region from a temperature near where the change in the apparent viscosity sharply decreases to a sufficiently low temperature and a sufficiently high temperature. Therefore, a tangent line is drawn on each of the curves before and after the temperature at which the temperature dependence of the apparent viscosity sharply decreases, and the temperature corresponding to the point where these two tangent lines intersect is determined to be the apparent viscosity stabilization start temperature (Tv). (Blistering resistance temperature): The molded test piece was kept in a high temperature oven under a nitrogen atmosphere at a predetermined temperature for 2 hours, and then taken out of the oven to observe whether or not blisters were generated on the surface. The temperature was raised at intervals of 5 ° C., and the temperature at which blister formation was observed was taken as the blister resistance temperature. (Heat distortion temperature, HDT): For molded test pieces,
It was measured according to the ASTM D648 test method (load 18.5 kg / cm ² ).

The polyesters obtained in the following Examples and Comparative Examples all showed optical anisotropy when heat-melted. In addition, in the production of polyester test pieces obtained in the following Examples and Comparative Examples, an injection molding machine (Sumitomo Heavy Industries, Ltd., SG-25 type) was used, and the cylinder temperature was set to the above " The apparent viscosity stabilization start temperature "was set, and injection molding was performed according to a conventional method. It was confirmed that any of the molding operations could be stably performed without any abnormalities, and that a test piece having a prescribed size was obtained, so that the “apparent viscosity stability onset temperature” described above serves as a guide for the molding temperature.

<Example 1> 1,105.44 g (8.0%) of p-hydroxybenzoic acid (HBA) was added to a polymerization tank having an anchor type stirring blade and having a small clearance between the wall of the polymerization tank and the stirring blade.
0 mol), 4,4'-biphenol (BP) 659.93
g (3.544 mol), terephthalic acid (TPA) 631.
29 g (3.80 mol), 4,4'-biphenyldicarboxylic acid (BP-DC) 48.45 g (0.20 mol) and hydroquinone (HQ) 52.85 g (0.48 mol) were charged (see Table 1). ), After vacuum drying, acetic anhydride 1,720.
26 g was added, and acetylation reaction was carried out at 150 ° C. for 3 hours under reflux of acetic anhydride. After that, the temperature was raised, and the temperature was raised to 280 ° C. at a rate of 1 ° C./min while the acetic acid was distilled off, and the temperature was maintained for 1 hour. Then, the temperature was raised to 300 ° C. at a rate of 1 ° C./min and held for 1 hour, further raised to 330 ° C. at the same rate and held for 20 minutes to carry out deacetic acid polymerization, and then the obtained polymer Was taken out from the outlet. After crushing the polymer taken out, under a nitrogen atmosphere, at 280 ° C. for 2 hours, 30
Heat treatment was performed at 0 ° C. for 2 hours and then at 320 ° C. for 5 hours. 6 of the polymer after heat treatment and the milled glass fiber
When the test pieces were mixed by a 0/40 weight ratio and injection-molded, stable molding was possible. The physical properties and moldability of the obtained test piece are shown in Table 2.

<Examples 2 to 5> Using the same apparatus as in Example 1 and using the amounts shown in Table 1, p-hydroxybenzoic acid (HBA), 4,4'-biphenol (BP), Terephthalic acid (TPA), 4,4′-biphenyldicarboxylic acid (BP-DC) and hydroquinone (HQ) were charged, and polymerization, heat treatment, mixing and molding of a test piece were carried out in the same manner as in Example 1. All could be molded stably. The physical properties and moldability of the obtained test piece are shown in Table 2.

<Examples 6 and 7> Using the same apparatus as in Example 1 and using the amounts shown in Table 1, p-hydroxybenzoic acid (HBA), 4,4'-biphenol (BP), Terephthalic acid (TPA), isophthalic acid (IPA) and 4,4′-biphenyldicarboxylic acid (BP-DC) were charged, and after vacuum drying, 1,720.26 g of acetic anhydride was added,
The acetylation reaction was carried out at 150 ° C. for 3 hours under reflux of acetic anhydride. After that, the temperature is raised to 280 while acetic acid is distilled off.
The temperature was raised to 1 ° C / min at a rate of 1 ° C / min and held for 1 hour. Then, the temperature was raised to 300 ° C. at a rate of 1 ° C./min and held for 1 hour, further raised to 330 ° C. at the same rate and held for 1 hour to carry out deacetic acid polymerization, and then the obtained polymer was extracted. I took it out of my mouth. After crushing the polymer taken out, under nitrogen atmosphere, 250 ° C. for 1 hour, 280 ° C. for 2 hours, 300 ° C.
For 2 hours and further at 320 ° C. for 5 hours. Heat treated polymer and milled glass fiber 60/40
When the test pieces were mixed at a weight ratio and injection-molded, stable molding was possible. The physical properties and moldability of the obtained test piece are shown in Table 2.

<Comparative Examples 1 to 7> Using the same apparatus as in Example 1 and using the amounts shown in Table 1, p-hydroxybenzoic acid (HBA), 4,4'-biphenol (BP), Terephthalic acid (TPA), isophthalic acid (IPA) and phenylhydroquinone (Ph-HQ) were charged, and polymerization, heat treatment, mixing and molding of test pieces were carried out in the same manner as in Example 1. Table 2 shows the physical property values and moldability of the obtained molded product.

<Comparative Examples 8 and 9> Using the same apparatus as in Example 1 and using the amounts shown in Table 1, p-hydroxybenzoic acid (HBA), 4,4'-biphenol (BP), Terephthalic acid (TPA) and isophthalic acid (IPA) were charged, and polymerization, heat treatment, mixing, and molding of a test piece were performed in the same manner as in Example 1. Table 2 shows the physical property values and moldability of the obtained molded product.

<Comparative Example 10> In this comparative example, Table 1
Since the proportion of BP-DC is as high as 10 mol% as shown in (3), the resulting polyester was markedly colored because the polymerization time was lengthened. Therefore, no physical property test was conducted.

[0036]

[Table 1]

[0037]

[Table 2]

FIG. 1 shows the apparent viscosity stabilization start temperature of the compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 7, that is, the correlation between the molding temperature and the heat distortion temperature. In FIG. 1, the data of the compositions of Examples 1 to 5 are all above the straight line of heat distortion temperature (° C.) = Molding temperature (° C.)-78 ° C., and compared with the compositions of Comparative Examples 1 to 7, The heat distortion temperature is kept higher than the molding temperature. From this, it is understood that the wholly aromatic polyester of the present invention has a feature that the heat distortion temperature can be kept high even when the molding temperature is low.

Further, the correlation between the apparent viscosity stabilization start temperature and the blister resistance temperature of the compositions of Examples 1 to 5 and Comparative Examples 1 to 7 is shown in FIG. In FIG. 2, all the data of the compositions of Examples 1 to 5 are above the straight line of blister resistance (° C.) = Molding temperature (° C.) − 90 ° C., and compared with the compositions of Comparative Examples 1 to 7, The blister resistance is kept high with respect to the molding temperature. From this, it can be seen that the wholly aromatic polyester of the present invention has a feature that the blister resistance can be kept high even when the molding temperature is low. Further, the results in Table 2 show that the aromatic polyester having a value (Tv-Tm) obtained by subtracting Tm from Tv is less than + 10 ° C has high heat resistance, particularly blister resistance.

[0040]

EFFECTS OF THE INVENTION The wholly aromatic polyester of the present invention has better moldability, and has improved heat distortion temperature and blister resistance as compared with known polyesters. That is, although the molding temperature is relatively low, the heat distortion temperature and the blister resistance temperature show high values.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between an apparent viscosity stabilization start temperature (molding temperature) and a heat distortion temperature.

FIG. 2 is a graph showing the relationship between the apparent viscosity stabilization start temperature (molding temperature) and the blister resistance temperature.

Claims (3)

(57) [Claims] 1. An aromatic polyester having optical melt anisotropy, which comprises a structural unit represented by the following formula (1) to formula (6). [Chemical 1] (The above k, l, m, n, o and p represent the content ratio (mol%) of each structural unit in the polyester, and 20 <k
≦ 80, l + m and n + o + p are substantially equal, and 0 ≦ o
The relationship is ≦ 10, 1 ≦ p ≦ 7, 0 ≦ m ≦ (l + m) / 2. ) 2. An aromatic polyester comprising the structural unit according to claim 1 and satisfying the relationship of the following formula: Tv-Tm <+ 10 ° C. [where Tm is a differential scanning calorimeter] Melting point (Tm, ° C) measured by (DSC), and Tv is a value measured by a capillary rheometer at a temperature (apparent viscosity stabilization start temperature, ° C) at which the change in apparent viscosity due to temperature sharply decreases. . ] 3. A polyester resin composition obtained by blending the aromatic polyester having optical melt anisotropy according to claim 1 with an inorganic filler in an amount of 95% by weight or less (composition).