JPH0841187A - Wholly aromatic polyester and its composition - Google Patents

Abstract

PURPOSE:To obtain a resin excellent in both heat resistance and moldability by specifying the relationship between the melting point of an optically melt anisotropic wholly aromatic polyester comprising specified structural units and its solidification initiation temperature. CONSTITUTION:This polyester is an optically melt anisotropic wholly aromatic polyester comprising three kinds of repeating units of formula I (wherein Ar is either of structures of formula II; X and Y are each a hydrocarbon group, O, S, SO, SO2 or CO; s, t, u and v are each 0 or 1; and the substituents in the benzene ring are para or meta to each other), wherein the difference Tm-Ts (wherein Tm ( deg.C) is the melting point as measured by DSC, and Ts ( deg.C) is the solidification initiation temperature as measured with a capillary rheometer) is 10-50 deg.C, and the contents of the structural units of the respective kinds p, q and r (mol%) are such that 10<=p<=90 and q is substantially equal to r. It is desirable from the viewpoints of heat resistance and moldability that the polyester has Tm of 290-440 deg.C and Ts of 240-430 deg.C. Because of its excellent properties, this polyester can be applied to various molded parts and especially when it is applied to an oven wear, this wear has markedly excellent resistance to oven blistering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wholly aromatic polyester having a high elastic modulus and having an optical melt anisotropy excellent in moldability and heat resistance. More specifically, the present invention relates to a wholly aromatic polyester having specific physical properties, and an organic material having a high elastic modulus and excellent heat resistance, which is obtained by orienting a molecular chain in the flowing direction under a flowing state.

[0002]

2. Description of the Related Art A wholly aromatic polyester having optical melt anisotropy has excellent physical properties based on its structure. In particular, this resin is the best among all resins in terms of heat resistance. Among them, a wholly aromatic polyester having optical melt anisotropy obtained from p-hydroxybenzoic acid or its derivative; terephthalic acid, isophthalic acid or its derivative; and 4,4′-dihydroxybiphenyl or its derivative is Moldable and excellent in various physical properties, especially mechanical properties and electrical properties. Furthermore, high heat resistance, chemical resistance, oil resistance, radiation resistance, dimensional stability, etc. It is known that the resin has almost all of the above.

[0003]

On the other hand, a wholly aromatic polyester having optical melt anisotropy is excellent in heat resistance indicated by a heat distortion temperature, but its molded product, for example, an injection molded product, is exposed to a high temperature. It has been pointed out that an oven blister (blister) is likely to occur on the surface of the molded product at that time, and it has been conventionally pointed out that there is a problem in moldability. Conventionally, the cause of oven blisters is the generation of decomposition gas due to the thermal deterioration of the resin during molding,
Alternatively, it is considered to be due to decomposition gas when the molded product is exposed to high temperature for a long period of time. Therefore, if the thermal stability of the resin can be improved, the occurrence of oven blisters is considered to be suppressed.

As a conventional method for improving the thermal stability of a resin, for example, in JP-A-59-4622, it is possible to reduce the temperature by adding a phosphite compound during polymerization in the production of wholly aromatic polyester. It has been proposed to obtain polymers with a degree of coloration and excellent thermal stability. Further, Japanese Patent Application Laid-Open No. 57-135830 proposes a method of copolymerizing a monohydric phenol to block the polymer terminal to enhance the thermal stability in a molten state. However, even with wholly aromatic polyesters produced by the methods described in these publications, the effect of suppressing the occurrence of oven blisters is still insufficient. That is, it was extremely difficult to improve the blister resistance by the conventional method for improving the thermal stability.

Further, as a general method for improving moldability, a method of copolymerizing a monomer having a flexible chain such as ethylene glycol or a non-linear monomer such as 2-hydroxy-6-naphthoic acid is used. A method of lowering the melting point of the polymer by the method of polymerizing has also been proposed. But,
In these methods, the moldability is improved by lowering the melting point, but the heat resistance indicated by the heat distortion temperature is remarkably lowered, and the oven blister resistance is not sufficiently improved.

The wholly aromatic polyester having optical melt anisotropy is generally a copolymer composed of several kinds of monomer components. In the case of a copolymer, there is a possibility that the arrangement of the monomer units, that is, the basic structure that affects basic physical properties such as melting point and melting behavior may change due to the difference in sequence. Further, the basic structure of the copolymer may be changed by copolymerizing a small amount of a comonomer such as hydroxycarboxylic acid. Therefore,
A wholly aromatic polyester having different basic physical properties may be obtained even if the composition and type of main monomers are the same. Furthermore, the relationship between the structure of wholly aromatic polyester and application properties such as oven blister resistance and moldability has not been clarified until now. Therefore, at present, it is practically difficult to obtain a wholly aromatic polyester having excellent oven blister resistance and good material properties such as moldability.

[0007]

[Means for Solving the Problems] In view of such circumstances,
The present inventors synthesized various wholly aromatic polyesters having optical melt anisotropy and conducted diligent research on them for the purpose of improving oven blister resistance and molding processability. The present invention has been achieved by finding that when a specific relationship is established between the melting point and the solidification start temperature, the oven blister resistance and the moldability are dramatically improved. That is, the present invention provides the following chemical formula 3.
(1) to (3)

[0008]

Embedded image

(The above p, q and r represent the content ratio (mol%) of each structural unit in the wholly aromatic polyester,
The relationship of 10 ≦ p ≦ 90 is satisfied, and q and r are substantially equal. Ar in the above formula has the structure shown in formula (1) or formula (2)

[0010]

[Chemical 4]

X and Y are hydrocarbon groups, --O--, --S.
-, - SO -, - SO 2 -, - CO- or -C (CH _3)
2- and s, t, u and v are integers of 0 or 1. Further, the substituents on the benzene ring in each formula are in the para or meta position relative to each other. ) Is a wholly aromatic polyester having optical melting anisotropy, which is composed of repeating constitutional units represented by the formula (1), and has a melting point (Tm, ° C) measured by DSC and a solidification onset temperature (measured by a capillary rheometer ( The present invention relates to a wholly aromatic polyester having a difference (Tm-T [eta]) in the range of 10 to 50 [deg.] C.

The present invention will be further described below. Examples of the monomer of the aromatic polyester precursor corresponding to the repeating constitutional unit represented by the formula (1) in the chemical formula 3 in the present invention include:
p-Hydroxybenzoic acid, m-hydroxybenzoic acid and their derivatives are mentioned. As the derivative, a precursor monomer capable of producing a repeating constitutional unit represented by the formula (1) by a polyesterification reaction involving polycondensation, for example, phenyl p-hydroxybenzoate, p-acetoxybenzoic acid, p-
Examples include methyl hydroxybenzoate and methyl p-acetoxybenzoate. These precursor monomers can be used alone or as a mixture.

Monomers of the aromatic polyester precursor corresponding to the repeating constitutional unit represented by the formula (2) of the above chemical formula 3 include terephthalic acid, isophthalic acid, p, p'-biphenyldicarboxylic acid, and 2,2. -Bis (4-carboxyphenyl) propane, 4,4'-dicarboxydiphenyl ether, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl sulfone, 4,4'-dicarboxydiphenyl sulfide and derivatives thereof Is mentioned.
As the derivative, a precursor monomer capable of forming a repeating constitutional unit represented by the formula (2) by a polyesterification reaction for polycondensation, for example, a diphenyl ester of the above dicarboxylic acid,
Examples thereof include dimethyl ester and diethyl ester. These precursor monomers can be used alone or as a mixture.

As the monomer of the aromatic polyester precursor corresponding to the repeating constitutional unit represented by the formula (3) in the chemical formula 3, hydroquinone, resorcin, 4,4'-dihydroxybiphenyl, 4,4'- Dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone,
4,4'-dihydroxydiphenyl sulfide, 4,4'-
Examples include dihydroxydiphenylbenzophenone, bisphenol A, 2,6-naphthalenediol and derivatives thereof. Examples of the derivative include a precursor monomer capable of forming a repeating constitutional unit represented by the formula (3) by a polyesterification reaction involving polycondensation, such as 4,4′-diacetoxydiphenyl. These precursor monomers can be used alone or as a mixture.

In the obtained wholly aromatic polyester, the content ratio p (mol%) of the repeating constitutional unit represented by the formula (1) of Chemical formula 3 must be in the range of 10≤p≤90. . Further, the content ratios q and r of the repeating constitutional units represented by the formulas (2) and (3) in Chemical Formula 3 need to be substantially equal values. If it deviates from these ranges, the moldability will be significantly reduced.

As a combination of these monomers,
As a monomer corresponding to the formula (1) of Chemical formula 3, p-hydroxybenzoic acid or an ester derivative thereof,
Monomers corresponding to the formula include terephthalic acid, isophthalic acid, p, p′-biphenyldicarboxylic acid, and 2,2-bis (4
-Carboxyphenyl) propane, 4,4'-dicarboxydiphenyl ether, 2,6-naphthalenedicarboxylic acid or their ester derivatives, and 4,4'-dihydroxybiphenyl, hydroquinone as a monomer corresponding to the formula (3), It is particularly preferable to select from each of 6,6-naphthalenediol and ester derivatives thereof.

The wholly aromatic polyester of the present invention is a DSC.
Difference (Tm-T) between the melting point (Tm) measured in Step 1 and the solidification start temperature (Tη) measured by the capillary rheometer.
η) is essential to be in the range of 10 to 50 ° C.,
Particularly preferably, it is in the range of 20 to 50 ° C. Tm-Tη
If the value is less than 10 ° C., the effect of suppressing the occurrence of oven blister is insufficient and the moldability is also deteriorated, which is not preferable. If the value of Tm-T [eta] exceeds 50 [deg.] C., the heat distortion temperature is lowered and the oven blister resistance is deteriorated, which is not preferable.

Here, the melting point (Tm) measured by DSC means that the wholly aromatic polyester to be measured is completely melted in DSC (differential scanning calorimeter) and then cooled to room temperature at a rate of 10 ° C./min. Place the sample in a nitrogen atmosphere for 2
It is the melting point obtained from the melting peak obtained when the temperature was raised at a rate of 0 ° C./min. In the present invention, Tm is 290
A wholly aromatic polyester in the range of ℃ to 440 ℃ is preferred. Particularly preferably, it is in the range of 300 ° C to 420 ° C. If the Tm is less than 290 ° C, the heat resistance indicated by the heat distortion temperature is remarkably low, and if the Tm is more than 440 ° C, the formability is remarkably reduced, which is not preferable.

The solidification start temperature (Tη) measured by the capillary rheometer is the value of the crystallization start temperature obtained by the following measuring method using the capillary rheometer. A capillary with a diameter of 1.0 mm, a length of 40 mm and an inflow angle of 90 ° is used, and the shear rate is 1.
The temperature dependence of the apparent viscosity is measured at 00 sec ^-1 . The measurement is started at a temperature 40 ° C. higher than the Tm obtained by DSC, and is cooled at a constant rate of 4 ° C./min to determine the relationship between apparent viscosity and temperature. The solidification start temperature is the apparent viscosity-temperature curve obtained by the above measurement conditions,
Read the temperature at which the apparent viscosity starts to rise rapidly, and read Tη
And More specifically, the intersection of the tangents of the curve before and after the start of solidification is determined, and the temperature corresponding to this point is Tη. A wholly aromatic polyester having T η in the range of 240 to 430 ° C. is preferable. Especially preferably 250-
It is 400 ° C. When Tη exceeds 430 ° C, the moldability is remarkably deteriorated, and when it is less than 240 ° C, the heat resistance shown by the heat distortion temperature is remarkably low, and therefore neither is preferable.

The wholly aromatic polyester of the present invention can be produced according to the conventional polycondensation method of polyester, and the production method is not particularly limited, but typical production methods include, for example, the following (1) )-(4). (1) A method for producing a diacylated aromatic dihydroxy compound, an acylated aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid by deacetic acid polycondensation reaction. (2) A method for producing an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid, and an acetic anhydride by acetic anhydride polycondensation reaction. (3) A method for producing from an aromatic dihydroxy compound, a diphenyl ester of an aromatic dicarboxylic acid and a phenyl ester of an aromatic hydroxycarboxylic acid by a dephenol polycondensation reaction. (4) reacting an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid with a desired amount of diphenyl carbonate,
A method in which a carboxyl group is phenyl esterified, then an aromatic dihydroxy compound is added, and a dephenol polycondensation reaction is carried out.

For example, p-hydroxybenzoic acid (PHB
A) 4,4′-dihydroxybiphenyl (DHBP) and terephthalic acid (TPA) were charged into a reactor, acetic anhydride was added to the mixture for acetylation under reflux of acetic anhydride, and then the temperature was raised to 250 to 350 ° C. Polyester is obtained by deacetic acid polycondensation while distilling acetic acid in the temperature range. The polymerization time can be selected in the range of 1 hour to several tens of hours.

As the catalyst used in the polycondensation reaction, magnesium acetate, stannous acetate, tetrabutyl titanate,
Typical examples are lead acetate, sodium acetate, potassium acetate, antimony trioxide, and metal catalysts, which are particularly effective in dephenol polycondensation.

Further, in each of the above polycondensation methods, it is possible to use melt polymerization and solid phase polymerization together. That is,
It is possible to further increase the degree of polymerization of a polymer that has been polycondensed by melt polymerization by solid phase polymerization. For the solid phase polymerization, widely known methods can be used. For example, the polyester obtained by melt polymerization is heat-treated in an inert atmosphere such as nitrogen in a temperature range of 250 to 350 ° C. for 1 to 30 hours.

The polymerization vessel is not particularly limited, but is generally used for high-viscosity agitation equipment such as anchor type agitators, multi-stage agitators, spiral band agitators, spiral shaft agitators, etc. , And a stirred tank-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. Is desirable.

The wholly aromatic polyester of the present invention obtained as described above can be used alone or as a mixture of several kinds of wholly aromatic polyester. In any case, it can be obtained by appropriately selecting the kind of the monomer corresponding to the repeating structural unit of the formula (1) to the formula (3) of Chemical formula 3, the compounding ratio, the polymerization order, the catalyst and other polymerization conditions. It is important to polymerize the wholly aromatic polyester so that the Tm-Tη value is in the range of 10 to 50 ° C. In other words, using the value of Tm-Tη as an index, the above equation (1)
Polymerization is performed by selecting the type of monomer, the compounding ratio, the polymerization order, the catalyst, and other polymerization conditions corresponding to the formula (3).

The wholly aromatic polyester having optical melt anisotropy of the present invention has a weight average molecular weight of about 2,000 to 2.
00000, preferably about 4,000-100,000
Range. The molecular weight can be measured, for example, by measuring the end groups of a compressed film by infrared spectroscopy. In addition, as a general measurement method performed in solution, GPC
Can also be used.

The wholly aromatic polyester of the present invention contains various fibrous materials mainly for improving mechanical strength.
Granular and plate-like inorganic and organic fillers can be blended. 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 materials 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, antimony trioxide, alumina, calcium sulfate, calcium carbonate, and various metal powders. Examples of the plate-shaped filler include mica, glass flakes, various metal foils and the like.

Other examples of organic fillers include heat-resistant and high-strength synthetic fibers such as aromatic polyester, aromatic polyamide, and polyimide. When using these fillers, a sizing agent or a surface treatment agent is used 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. If the inorganic filler is blended in an amount of more than 95% by weight, the mechanical strength is rather lowered, which is not preferable.

Further, the wholly aromatic polyester of the present invention may be appropriately blended with another thermoplastic resin as long as the object of the present invention is not impaired.

The wholly aromatic polyester of the present invention obtained as described above makes use of its excellent properties and is conventionally known in the art such as extrusion molding, injection molding and blow molding. It is possible to process into fibers, films, three-dimensional molded products, containers, hoses, etc.

Examples of such concrete molded products are as follows. That is, as electric parts, 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.), tapes. 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 socket etc.), potentiometer (coil former etc.), soldering iron parts, casserole base and record player parts (tone arm bearings etc.).

The electronic parts include relay parts (housing, arc insulator, etc.), printed circuit boards, switches (housing, etc.), connectors, bobbins, electronic timepiece parts (housing, stator for trimmer capacitors, insulating materials, etc.), 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 part holders , Internal combustion engine cylinder internal pressure measuring device parts (ring element insulation etc.), battery parts (catalyst holder etc.), resistors, hearing aid parts, surface thermometer parts (couple parts etc.), and fuse parts (housing etc.) To be

Automotive parts include EGR valves (valve bodies, valve covers, valves, etc.), piston rings, apex seals, plug insulating materials, shock absorber parts (rings, bearings, etc.), bulldozer parts (piston rings, bearings, etc.). , Distributor parts (cam, housing, etc.), Ignition switch parts (housing, etc.), Brake parts (Brake material binder, brake, bleeder, etc.), Exhaust gas pipe parts (sleeve, etc.), Exhaust gas temperature sensor (housing, etc.), Wire Examples include cables, lamp parts (headlight reflectors, etc.), and automobile coolers.

As the sliding material and machine parts, parts for copying machines (separation claws, bearings, hot roll coating, etc.),
Computer parts (wear-resistant rings, etc.), line printer parts (guides, backup burring, etc.), compressor parts (piston rings, brakes, etc.),
Soy sauce manufacturing equipment Sliding materials, paper making dryer parts, spinning machine parts (spindle, pulley, crimper guides, etc.), projector parts, vending machine parts (bearings, etc.), glass manufacturing jigs, cathode ray tube manufacturing jigs, Jigs for electric wire production, jigs for can making machines, jigs for bottle manufacturing equipment (feeding claws, etc.), stern bearings, oilless bearings (oil bearings, three-layer bearings, etc.), underwater bearings, heat-resistant bearings for sterile 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 (insulation washers, etc.), extruder parts (dies, etc.), camera bodies, gas calorimeter parts (housing, etc.),
Examples include sewing machine parts (such as cams), lighter parts (such as housings), dial gauge parts, insulation materials for refrigerator stators, air conditioner parts (such as mufflers), robot parts, oven bearings, and gasoline filters.

In addition, synchrotron parts, TLD parts (caps, etc.), abradable seals, binders for grindstones, simple molds, heat-resistant fiber aircraft in-flight tableware,
It can be used as a ski.

The molded product thus obtained is
Heat treatment can increase strength and in many cases also increase elastic modulus. This heat treatment is performed by heat-treating the molded article in an inert atmosphere (for example, in nitrogen, argon, helium, or steam), an oxygen-containing atmosphere (for example, in air), or under reduced pressure at a temperature not higher than the melting point of the polymer. You can

In addition to the above-mentioned applications, a molded article obtained by molding the wholly aromatic polyester having optical melt anisotropy of the present invention is a tableware for oven, range, or both.
Alternatively, it is particularly preferably used for interior parts used inside a tableware heater. Examples of such interior parts include a trifurcated stay, a bracket, a rotary table, a rotary hub, a top plate protection cover, a plug cover, etc., which are exposed to a high temperature atmosphere at least inside the heater at the time of use. It is an internal component. The type of heating may be a microwave oven type, electric resistance heating or the like, or may be gas combustion heating or the like. Further, the molded body according to the present invention is heated in these heaters,
For example, it can be used as ovenware such as plate-shaped or box-shaped tableware. The application to the heater interior parts and ovenware will be described below.

When it is used as an interior component used in the interior of a tableware heater for an oven, a microwave oven, or both, the wholly aromatic polyester having optical melting anisotropy of the present invention is added to the above-mentioned general As in the case of the molded product, various kinds of fibrous, powdery, and plate-like inorganic and organic fillers can be appropriately mixed. As the fibrous filler, granular filler and plate-like filler, the same various substances as described above are used.

In the above case, particularly preferable inorganic fillers include talc, glass fibers, glass beads, silica-alumina fibers and the like. Talc has a weight loss of about 6% or less at 950 ° C when heated, and iron oxide (Fe ₂ O
It is preferable that the iron content analyzed as ₃ ) is 1% or less. The glass fiber is generally used as a reinforcing agent for resins, and is a short fiber called a milled glass fiber having a diameter of 5 to 15 μm and a fiber length of 50 to 250 μm, and a chopped glass fiber having a fiber length of 2 to 5 mm. The long fibers referred to as are applied. As silica-alumina fibers, various composition ratios containing silica and alumina as main components are commercially available, and are generally called ceramic fibers. These include siliceous fibers or alumina fibers having silica or alumina as a main component. A typical silica-alumina fiber is a fiber obtained by electromelting approximately equal amounts of high-purity silica and alumina, and blowing the fine stream away with high-pressure air to form a fiber. Is about 200 μm. The glass beads may be used without treatment, but in order to improve the affinity with the resin within a range that does not impair the effects of the present invention, they are used after being surface-treated with aminosilane, epoxysilane coupling agent, etc. May be.

Further, regarding the blending amount of the inorganic filler, the use of the organic filler, the addition of various additives and other thermoplastic resins, the same treatments as in the case of the above general molded article can be carried out. Furthermore, known methods such as Japanese Patent Publication No. 4-
It can also be coated with a fluororesin by the method described in 20327.

The means of compounding and molding for obtaining a heater interior part or ovenware using the present invention is not particularly limited. The wholly aromatic polyester and the compounding material are mixed using a Henschel mixer, a tumbler, etc., and then melt-kneaded using an extruder to form a compound, and the compound is injection-molded by a known method.

[0044]

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. (Melting point): Measured by the above method using SSC-5020 manufactured by Seiko Denshi Kogyo Co., Ltd. as a DSC device. (Solidification start temperature): As a capillary rheometer
It is measured by the above method using a model 2010 manufactured by Intesco Corporation. (Oven-proof blister temperature): A test piece molded by injection molding is kept at a predetermined temperature in a high temperature oven for 2 hours in a nitrogen atmosphere, and then taken out of the oven to check for the occurrence of surface blister. I observed. The temperature is 5
The temperature is raised at intervals of ° C, and the temperature at which blister formation is observed is defined as the oven blistering temperature.

The wholly aromatic polyesters obtained in the following Examples and Comparative Examples all exhibited optical anisotropy when melted. In addition, an injection molding machine (SG-25 manufactured by Sumitomo Heavy Industries, Ltd.) was used for manufacturing the test pieces.
Mold) was used and injection molding was performed according to a conventional method.

Example 1 In 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, 4,
4'-diacetoxybiphenyl 1,086.5 g (4.02
Mol) and terephthalic acid 584.8 g (3.52 mol)
Was charged, and after vacuum drying, 960 g of acetic acid was added, the temperature was raised from room temperature to 170 ° C. at a rate of 1 ° C./min, and p-acetoxybenzoic acid 1,441.28 was vacuum dried in advance.
g (8.00 mol) and 103.8 g (0.48 mol) of 2,6-naphthalenedicarboxylic acid. Then, the temperature was raised to 280 ° C. at a rate of 1 ° C./minute while the acetic acid was distilled off, and the temperature was maintained for 45 minutes. Next, the temperature is raised to 300 ° C. at a rate of 1 ° C./minute and held for 30 minutes, and further to 320 ° C. for 1 minute.
After the temperature was raised at a rate of ° C / min and the temperature was maintained for 20 minutes, the obtained polymer was taken out from the outlet. The polymer taken out was pulverized by a pulverizer and heat-treated in a nitrogen atmosphere at 280 ° C. for 2 hours, 300 ° C. for 2 hours, and 320 ° C. for 5 hours. When 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, stable molding at 405 ° C. was possible. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

Example 2 Using the same apparatus as in Example 1, 4,8'-diacetoxybiphenyl 1,086.5 g
(4.02 mol), terephthalic acid 584.8 g (3.52 mol)
Mol) was added, and after vacuum drying, 960 g of acetic acid was added and the temperature was raised from room temperature to 170 ° C. at a rate of 1 ° C./minute, and then vacuum dried p-acetoxybenzoic acid 1,44.
1.28 g (8.00 mol) and 124.0 g (0.48 mol) of 4,4'-dicarboxydiphenyl ether were added. Then, melt polymerization was performed in the same manner as in Example 1, and the polymer was taken out through the outlet. The polymer taken out is pulverized by a pulverizer, and 280 ° C under a nitrogen atmosphere.
2 hours, 300 ° C. for 2 hours, and 320 ° C. for 7 hours. When 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, stable molding was possible at 415 ° C. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

<Example 3> Using the same apparatus as in Example 1, 4,8'-diacetoxybiphenyl 1,086.5 g
(4.02 mol) and terephthalic acid 584.8 g (3.
(52 mol), and after vacuum drying, 960 g of acetic acid was added, the temperature was raised from room temperature to 170 ° C. at a rate of 1 ° C./min, and 1,441.28 g (8) of p-paraacetoxybenzoic acid that had been vacuum dried in advance was added. 0.00 mol) and 2,2-bis
(4-Carboxyphenyl) propane 136.4 g (0.4
8 mol) was added. Then, melt polymerization was performed in the same manner as in Example 1, and the polymer was taken out through the outlet.
The polymer taken out was pulverized by a pulverizer, and the mixture was nitrous atmosphere at 280 ° C. for 2 hours, 300 ° C. for 2 hours, and further 32
Heat treatment was performed at 0 ° C. for 6 hours. 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber are mixed,
When a test piece was injection-molded, it could be stably molded at 415 ° C. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

<Example 4> Using the same apparatus as in Example 1, 956.8 g of 4,4'-diacetoxybiphenyl (3.
54 mol) and 664.5 g (4.00 mol) of terephthalic acid were added, and after vacuum drying, 960 g of acetic acid was added, the temperature was raised from room temperature to 170 ° C. at a rate of 1 ° C./minute, and then vacuum dried p -Acetoxybenzoic acid 1,441.
28 g (8.00 mol) and 117.4 g (0.48 mol) of 2,6-diacetoxynaphthalene were added. Then, melt polymerization was performed in the same manner as in Example 1, and the polymer was taken out through the outlet. The polymer taken out was pulverized by a pulverizer, and the mixture was placed in a nitrogen atmosphere at 280 ° C. for 2 hours for 3 hours.
Heat treatment was performed at 00 ° C. for 2 hours and further at 320 ° C. for 4 hours. When 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, stable molding at 400 ° C. was possible. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

Comparative Example 1 Using the same apparatus as in Example 1, 1105.4 g (8.00 g) of p-hydroxybenzoic acid was used.
Mol), 4,4'-dihydroxybiphenyl 748.6 g
(4.02 mol) and terephthalic acid 664.5 g (4.
(00 mol), and vacuum dried, followed by acetic anhydride 1.72
0.3 g was added, and an acetylation reaction was carried out at 150 ° C. for 3 hours under reflux of acetic anhydride. Then, the temperature is raised, and the temperature is raised to 280 ° C. at a rate of 1 ° C./min while distilling off acetic acid.
Held minutes. Then, the temperature was raised to 300 ° C. at a rate of 1 ° C./min and held for 45 minutes, further raised to 320 ° C. at a rate of 1 ° C./min and held for 20 minutes, and then the obtained polymer was taken out from the outlet. I took it out. The polymer taken out was pulverized by a pulverizer, and it was stored in a nitrogen atmosphere at 280 ° C. for 2 hours for 30 hours.
Heat treatment was performed at 0 ° C. for 2 hours and further at 340 ° C. for 5 hours. When 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, it could be molded at 430 ° C. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

Comparative Example 2 Using the same apparatus as in Example 1, 1,105.4 g (8.00 g) of p-hydroxybenzoic acid was used.
Mol), 4,4'-dihydroxybiphenyl 659.2 g
(3.54 mol), terephthalic acid 664.5 g (4.00)
Mol) and 4,4′-dihydroxydiphenyl ether 97.1 g (0.48 mol) were charged, and after vacuum drying, 1,720.3 g of acetic anhydride was added and melt polymerization was performed by the same operation as in Comparative Example 1, The polymer was taken out through the outlet. The polymer taken out was pulverized by a pulverizer and heat-treated in a nitrogen atmosphere at 280 ° C. for 2 hours, 300 ° C. for 2 hours, and 320 ° C. for 7 hours. Polymer 6 after heat treatment
When 0 part by weight and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, it could be molded at 425 ° C. Table 1 shows Tm, Tη, injection pressure at the time of injection molding and oven blister resistance of the obtained polymer.
Shown in

Comparative Example 3 Using the same apparatus as in Example 1, 1105.4 g (8.00 g) of p-hydroxybenzoic acid was used.
Mol), 4,4'-dihydroxybiphenyl 659.2 g
(3.54 mol), terephthalic acid 664.5 g (4.00)
Mol) and 52.8 g (0.48 mol) of hydroquinone were added, and after vacuum drying, 1,720.3 g of acetic anhydride was added, and melt polymerization was carried out in the same manner as in Comparative Example 1 to extract the polymer. I took it out. The polymer taken out was pulverized by a pulverizer and heat-treated in a nitrogen atmosphere at 280 ° C. for 2 hours, 300 ° C. for 2 hours, and 320 ° C. for 7 hours. When 60 parts by weight of the polymer after heat treatment and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, it could be molded at 435 ° C. Table 1 shows Tm, Tη, injection pressure during injection molding, oven blister resistance, etc. of the obtained polymer.

<Comparative Example 4> Using the same apparatus as in Example 1, 1,105.4 g of p-hydroxybenzoic acid (8.
00 mol), 4,4'-dihydroxybiphenyl 748.
6 g (4.02 mol), terephthalic acid 584.8 g (3.
52 mol) and 1,4-naphthalenedicarboxylic acid 10
3.8 g (0.48 mol) was charged, and after vacuum drying, 1,720.3 g of acetic anhydride was added, melt polymerization was carried out by the same operation as in Comparative Example 1, and the polymer was taken out from the outlet. The polymer taken out was pulverized by a pulverizer and heat-treated in a nitrogen atmosphere at 280 ° C. for 2 hours, 300 ° C. for 2 hours, and 320 ° C. for 4 hours. Polymer 6 after heat treatment
When 0 part by weight and 40 parts by weight of milled glass fiber were mixed and a test piece was injection-molded, it was possible to mold at 420 ° C. Table 1 shows Tm, Tη, injection pressure at the time of injection molding and oven blister resistance of the obtained polymer.
Shown in

[0054]

[Table 1]

According to the results shown in Table 1, the wholly aromatic polyester having a Tm-Tη value in the range of 10 to 50 ° C. has a low molding pressure at the time of injection molding and has a high resistance to moldings. The oven blister temperature has risen dramatically. That is, it is understood that the wholly aromatic polyester of the present invention is excellent in both moldability and oven blister resistance.

[0056]

EFFECT OF THE INVENTION The wholly aromatic polyester of the present invention has good moldability, and further, the oven blister resistance is dramatically improved. Therefore, the wholly aromatic polyester having optical melt anisotropy of the present invention is particularly suitable for a molded article such as an oven, a tableware for a range or both, or a molded article such as an interior part used inside the heater thereof. is there.

Claims (4)

[Claims] 1. A formula (1) to a formula (3) below: Which is a wholly aromatic polyester having optical melting anisotropy consisting of repeating constitutional units represented by the formula (1), and having a melting point (Tm, ° C) measured by DSC and a solidification start temperature (Tη, measured by a capillary rheometer). Temperature difference (Tm-
T η) in the range of 10 to 50 ° C., with wholly aromatic polyesters, provided that p, q and r
Represents the content ratio (mol%) of each structural unit in the wholly aromatic polyester, satisfies the relationship of 10 ≦ p ≦ 90, and q and r are substantially equal. Ar in the above formula has the structure shown in Formula (1) or Formula (2) of Chemical Formula 2, X and Y are hydrocarbon groups, -O-, -S-, -SO-,
-SO ₂ -, - CO- or -C (CH _{3) 2} - and is,
s, t, u and v are integers of 0 or 1. Also,
The substituents on the benzene ring in each formula are in the para or meta position relative to each other. 2. The wholly aromatic polyester according to claim 1, wherein the Tm is in the range of 290 ° C. to 440 ° C. 3. The wholly aromatic polyester according to claim 1, wherein the T η is in the range of 240 to 430 ° C. 4. A wholly aromatic polyester having optical melt anisotropy according to claim 1, and 95 based on the total composition.
A wholly aromatic polyester resin composition comprising an inorganic filler in an amount of not more than 5% by weight.