JPH05186671A - Thermotropic liquid crystal polyester composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having heat resistance, mechanical strength and chemical resistance, low melt viscosity and excellent low- temperature moldability by blending two kinds of polyesters showing optical anisotropy at specific temperatures, respectively. CONSTITUTION:(A) 99-60 pts.wt. polyester showing optical anisotropic melt phase at <=250 deg.C is blended with 1-40 pts.wt. polyester forming optical anisotropic melt phase at <=200 deg.C, comprising units of formula I to formula IV (Ar is 1,4-phenylene or 2,6-naphthalene), having the equal number of mols of the units I and II, 15-90mol% total amounts of the units I and II, 85-10mol% total amounts of the units III and IV and a ratio of the unit III to the total amounts of the units III and IV of >=10% to give the objective composition. The component B, for example, is obtained by subjecting polyethylene naphthalate-based polyester to acidolysis with 6-acyloxy-2-naphthoic acid and a p-acyloxybenzoic acid and increasing the degree of polymerization of the formed substance.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermal liquid crystal polyester composition having excellent moldability and mechanical properties.

[0002]

2. Description of the Related Art Polyesters having the property of forming an optically anisotropic molten phase, that is, thermal liquid crystal polyesters, are
Since it has high rigidity, high heat resistance, excellent chemical resistance, and good moldability, it has attracted attention in various fields, and in recent years, various thermal liquid crystal polyesters have been proposed.
However, in most thermo-liquid crystalline polyesters, the rigid component of the resin itself is likely to be oriented, so that fibrillation is likely to occur, the anisotropy of the mechanical properties of the molded product is large, and further, it requires a considerably high temperature for melt molding. It also has drawbacks such as the need for. On the other hand, a thermal liquid crystal polyester that gives a molded product having small anisotropy of mechanical properties has also been proposed. For example, JP-A-60-28428 proposes a polyester having a terephthaloyl group, a 1,3-dioxyphenylene group and a 2-substituted-1,4-dioxyphenylene group as a constituent unit. As described above, the introduction of the iso-skeleton and the substituent improves the moldability of the thermal liquid crystal polyester, and although not always sufficient, it tends to facilitate the production of various molded products.

[0003]

According to the study of the present inventors, the molded article obtained from the thermal liquid crystal polyester described in JP-A-60-28428 is a dynamic characteristic of conventional thermal liquid crystal polyester. It was found that the properties and heat resistance were significantly reduced. An object of the present invention is to provide a thermal liquid crystal polyester composition which is excellent in low temperature moldability while maintaining the heat resistance and mechanical strength of the conventional thermal liquid crystal polyester.

[0004]

According to the present invention, the above-mentioned object is polyester (hereinafter referred to as first polyester) 99 which forms an optically anisotropic molten phase at a temperature of 250 ° C. or higher. -60 parts by weight is mixed with 1-40 parts by weight of a polyester (hereinafter, referred to as a second polyester) that forms an optically anisotropic molten phase at a temperature of 200 ° C or less, and the second polyester is Substantially the following formula I

[0005]

[Chemical 5]

(Wherein Ar represents a 1,4-phenylene group or a 2,6-naphthylene group), a structural unit (1) represented by the following formula II

[0007]

[Chemical 6]

The structural unit (2) represented by the following formula III

[0009]

[Chemical 7]

The structural unit (3) represented by and the following formula I
V

[0011]

[Chemical 8]

The constitutional unit (4) is represented by the formula (1) and the constitutional unit (1) and the constitutional unit (2) are contained in substantially the same number of moles, and the total amount of the constitutional unit (1) and the constitutional unit (2) is 15 to 90 mol%, the total amount of the structural unit (3) and the structural unit (4) is 85 to 10 mol%, and the total amount of the structural unit (3) and the structural unit (4) is less than that of the structural unit (3). It is achieved by providing a thermotropic liquid crystal polyester composition characterized in that the proportion of the amount is 10 mol% or more.

The first polyester in the present invention is not particularly limited as long as it is a polyester which forms an optically anisotropic molten phase at a temperature of 250 ° C. or higher. From the viewpoint of stability, the temperature at which the optically anisotropic molten phase is formed is preferably 27.
Those in the range of 0 to 370 ° C. are preferable. The first polyester is produced from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aromatic diol or an ester-forming derivative thereof, an aromatic hydroxycarboxylic acid or an ester-forming derivative thereof, or an aromatic hydroxy group. It is produced from a carboxylic acid or an ester-forming derivative thereof, an aromatic dicarboxylic acid or an ester-forming derivative thereof, and an aromatic diol or an ester-forming derivative thereof. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, diphenylether-4,4'-dicarboxylic acid and methyl. Terephthalic acid, chloroterephthalic acid, etc. are used, and examples of aromatic diols include hydroquinone, resorcin, 2,6
-Dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4 '
-Dihydroxydiphenyl ether, chlorohydroquinone, methylhydroquinone, phenylhydroquinone, etc. are used, and examples of aromatic hydroxycarboxylic acids include p-hydroxybenzoic acid, m-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 7- Hydroxy-2-naphthoic acid, 4-hydroxydiphenyl-
4'-carboxylic acid, 3-chloro-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3-methyl-4-hydroxybenzoic acid and the like are used. In producing the first polyester, various ester forming reactions are utilized, and usually a melt polymerization method, and optionally a solid phase polymerization method is adopted.

The structural unit (1) of the second polyester in the present invention is specifically a terephthaloyl group and / or a naphthalene-2,6-dicarbonyl group. A part of the structural unit (1), for example, up to 20 mol% may be replaced with a structural unit that can be introduced by another dicarboxylic acid or its ester-forming derivative. Examples of the other dicarboxylic acid include isophthalic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid and sebacic acid. In addition, if the amount of the second polyester obtained is within a range capable of being melt-molded,
It is also possible to replace a part of the structural unit (1) with a structural unit that can be introduced by a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid or an ester-forming derivative thereof.

The constitutional unit (2) of the second polyester is
It is an ethylenedioxy group as introduced by ethylene glycol. A part of the structural unit (2), for example, up to 20 mol% may be replaced with a structural unit that can be introduced by another glycol. Examples of glycol components other than ethylene glycol include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2-methyl-
1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-
Cyclohexanedimethanol, diethylene glycol,
Examples include triethylene glycol, o-, m- or p-xylylene glycol. In addition, if the amount of the second polyester obtained is within a range capable of being melt-molded,
It is also possible to replace a part of the structural unit (2) with a structural unit that can be introduced by a polyhydric alcohol such as glycerin, trimethylolpropane, trimethylolpropane and pentaerythritol.

Structural unit (1) in the second polyester
And (2) are present in substantially equal molar numbers. These constituent units are usually mainly composed of a reaction of terephthalic acid or its ester-forming derivative with ethylene glycol, a reaction of 2,6-naphthalenedicarboxylic acid or its ester-forming derivative with ethylene glycol, or terephthalic acid and 2,2. The polyester obtained by reacting a mixture of 6-naphthalenedicarboxylic acid or an ester-forming derivative thereof with ethylene glycol is introduced as a raw material into the second polyester component.

The polyethylene terephthalate, polyethylene naphthalate or copolymers thereof used in the production of the second polyester can be produced by adopting the method conventionally established in the production of polyester such as polyethylene terephthalate. For example, it can be obtained by a method in which a dicarboxylic acid and a glycol are subjected to an esterification reaction and then polycondensation, a method in which a dicarboxylic acid ester and a glycol are transesterified, and then a polycondensation. In that case, it may sometimes be preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer, etc., but as these catalysts, stabilizers, etc., in the production of polyester, particularly polyethylene terephthalate. What is known as a usable catalyst, a stabilizer, etc. can be used. For example, catalysts that accelerate these reactions include sodium, magnesium, calcium, zinc, manganese, tin, tungsten,
Metal compounds such as germanium, titanium, antimony,
Further, examples of the stabilizer include phosphorus compounds such as phosphoric acid, phosphoric acid ester, phosphorous acid, and phosphorous acid ester. In addition, other additives (colorants,
UV absorbers, light stabilizers, antistatic agents, flame retardants, crystallization accelerators, etc.) can also be added.

The degree of polymerization of polyethylene terephthalate, polyethylene naphthalate or a copolymer thereof used as a raw material polyester in the production of the second polyester is not particularly limited, but at 30 ° C. in a mixed solvent of phenol / tetrachloroethane and the like. It is desirable to use one having an intrinsic viscosity of 0.01 to 1.5 dl / g measured in Step 1.

The above structural unit (1) and structural unit (2) are contained in the second polyester as their total amount,
It is present in the range 15-90 mol%, preferably in the range 25-85 mol%.

Structural unit (3) in the second polyester
Is 6-oxy-2-, as introduced by 6-hydroxy-2-naphthoic acid or its ester-forming derivatives.
It is a naphthoyl group, and the structural unit (4) is a 4-oxybenzoyl group as introduced by p-hydroxybenzoic acid or its ester-forming derivative. A part of the structural unit (3) and the structural unit (4), for example, up to 10 mol% can be replaced with a structural unit which can be introduced by another hydroxycarboxylic acid or an ester-forming derivative thereof. Examples of hydroxycarboxylic acids other than 6-hydroxy-2-naphthoic acid and p-hydroxybenzoic acid include m-hydroxybenzoic acid and 4-hydroxybenzoic acid.
Hydroxy-3-chlorobenzoic acid, 4-hydroxy-
Examples thereof include 3,5-dimethylbenzoic acid, 4-hydroxy-3-methylbenzoic acid, 7-hydroxy-2-naphthoic acid, 4-hydroxy-1-naphthoic acid and 5-hydroxy-1-naphthoic acid.

The above structural unit (3) and structural unit (4) are contained in the second polyester in the total amount thereof.
Suitably it is present in the range from 10 to 85 mol%,
It is more preferably present in the range of 15 to 75 mol%. The total amount of constituent unit (3) and constituent unit (4) is 8
If it exceeds 5 mol%, the melt polymerization becomes difficult, and the low temperature moldability of the resulting thermo-liquid crystal polyester composition may not be sufficiently exhibited, and if it is less than 10 mol%, the polyester obtained may be insufficient. Does not form thermal liquid crystals,
It is not preferable because uniform mixing with the first polyester becomes difficult.

The ratio of the amount of the structural unit (3) to the total amount of the structural unit (3) and the structural unit (4) is 1
It is necessary to be 0 mol% or more, which imparts extremely excellent low-temperature moldability to the thermo-liquid crystal polyester composition of the present invention.

Structural unit (3) in the second polyester
And the structural unit (4) is usually introduced into the polymer by using the corresponding acyloxycarboxylic acid as a raw material. The acyloxycarboxylic acid is preferably an acetoxycarboxylic acid obtained by reacting a corresponding hydroxycarboxylic acid with acetic anhydride.

For the production of the second polyester, for example, first, a polyethylene naphthalate type polyester, a polyethylene terephthalate type polyester, a copolymer or a mixture thereof is mixed with 6-acyloxy-2-naphthoic acid and p.
By preparing the polyester fragment by acidolysis with an acyloxybenzoic acid and subsequently increasing the degree of polymerization of this polyester fragment. The first stage acidolysis is usually carried out at 250 to 300 ° C. under an atmosphere of an inert gas such as nitrogen, argon or carbon dioxide. 6-acyloxy-
2-naphthoic acid and p-acyloxybenzoic acid are usually 6-acetoxy-2-naphthoic acid and p-
It is desirable to use acetoxybenzoic acid respectively.

6-acyloxy-2- as a raw material compound
Instead of using naphthoic acid and p-acyloxybenzoic acid, the corresponding hydroxycarboxylic acids (6-hydroxy-2-naphthoic acid and p-hydroxybenzoic acid) can be used, respectively. In that case, the hydroxycarboxylic acid is reacted with a lower aliphatic acid anhydride, preferably acetic anhydride, and substantially all the hydroxyl groups are converted into acyloxy groups, preferably acetoxy groups, and then the corresponding corresponding products are formed. By reacting the acyl ester with a predetermined raw material polyester without isolation, the second
Polyester is produced. In this case, the raw material polyester can be added to the system at any time before or after the acylation reaction of 6-hydroxy-2-naphthoic acid and p-hydroxybenzoic acid. In the acylation reaction stage of 6-hydroxy-2-naphthoic acid and p-hydroxybenzoic acid, in the case of a composition having a high content of 6-hydroxy-2-naphthoic acid, 6-acyloxy that is produced as the reaction proceeds. Since 2-naphthoic acid precipitates in the system and the reaction system becomes non-uniform, the subsequent reaction may not proceed smoothly. In such a heterogeneous system, not only the acylation reaction but also the next acidolysis reaction does not proceed smoothly,
At the same time, the production of a homopolyester of acyloxynaphthoic acid remarkably occurs, so that the randomness of the second polyester finally obtained is extremely poor. Therefore, in order to solve such a problem, in this acylation reaction step, the boiling point is about 100 to 300 ° C., and the acylation reaction and the subsequent acidolysis reaction and polycondensation reaction are adversely affected. It is desirable that a reaction solvent that does not exist coexist.

Most of the theoretical distillate amount of the lower aliphatic acid produced in the stage of the acidolysis reaction of 6-acyloxy-2-naphthoic acid and p-acyloxybenzoic acid with the raw material polyester goes out of the system. Then, the product of the acidolysis reaction remaining in the system is further reduced-lower aliphatic acid at 250 to 350 ° C. under reduced pressure, suitable for forming a desired article, preferably 0.1 dl / g or more. Increase degree of polymerization to logarithmic viscosity. In this case, the polymerization temperature is preferably 270 ° C. or higher from the viewpoint of reaction rate, and 350 ° C. or lower from the viewpoint of suppressing the decomposition of the polyester produced, and particularly preferably 270 to 320 ° C. Further, as a method for further increasing the degree of polymerization, it is possible to employ a solid-phase polymerization method or the like well known in the art depending on the composition.

The inherent viscosity of the second polyester in pentafluorophenol, measured at 60 ° C., is at least 0.
1 dl / g, but 0.3 dl / g from the viewpoint of the mechanical strength of the article molded from the thermo-liquid crystal polyester composition of the present invention.
It is desirable that it is g or more, and more preferably 0.5 dl / g or more. In addition, although there is no critical upper limit to the logarithmic viscosity, 3.0 dl / in terms of ease of melt polymerization, moldability, etc.
It is preferably g or less.

The first polyester, the second polyester and the composition comprising them in the present invention form a liquid crystal in the melt phase (indicating optical anisotropy). Confirmation of such optical anisotropy in the melt phase is carried out using a polarizing microscope equipped with a heating device, as is well known to the person skilled in the art, under the crossed Nicols, a slice of the sample, preferably 5-20 μm.
It can be performed by sandwiching a thin piece of about m in size between cover glasses, observing at a constant temperature rising rate, and seeing that light is transmitted at a certain temperature or higher. In this observation, the polarized light transmission can be more reliably observed by applying light pressure to the sample sandwiched between the cover glasses or sliding the cover glass at high temperature. In this observation, the temperature at which polarized light starts to transmit is the transition temperature to the optically anisotropic molten phase.

The transition temperature of the second polyester of the present invention to the optically anisotropic molten phase is difficult to determine by a differential scanning calorimeter, unlike that of the conventionally proposed thermal liquid crystal polyester. That is, as will be apparent from the examples described below, when the second polyester is measured by a differential scanning calorimeter, a clear endothermic peak may not be observed depending on the composition, and for example, when an endothermic peak is observed. However, the peak is not always based on the transition from crystal to liquid crystal. In the second polyester, the endothermic peak becomes smaller as the total amount of the structural unit (3) and the structural unit (4) increases, and when the total amount of the structural unit (3) and the structural unit (4) is 35 mol% or more. Often no endothermic peak is observed.

The mixing ratio of the first polyester and the second polyester in the thermal liquid crystal polyester composition of the present invention is (99-60) to (1-40) (weight),
From the viewpoint of the low temperature moldability of the composition, the strength of the molded article and the heat resistance, it is preferably (97 to 65) vs. (3 to 35) (weight), more preferably (95 to 70) vs. (5 to 30).
(Weight).

The thermal liquid crystal polyester composition of the present invention may be mixed with various additives or fillers by a method well known to those skilled in the art for the purpose of improving various mechanical properties thereof. As the additives, for example, those usually added to thermoplastic resins and thermosetting resins can be used, and specifically, plasticizers, antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, flame retardants. , Paints, pigments, foaming agents, lubricants and cross-linking agents. As the filler, glass fiber, carbon fiber, metal fiber, ceramic fiber, inorganic fiber such as asbestos, calcium carbonate, highly dispersible silicic acid, alumina, aluminum hydroxide, talc, mica, glass flakes, quartz powder, silica Examples include powder substances such as sand, carbon black, and barium sulfate, whiskers, and the like.

[0032]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, the measurement of the physical-property value in an Example followed the following method.

(1) Logarithmic viscosity (ηinh) 0.1 g / dl using pentafluorophenol solvent
The concentration was measured at 60 ° C.

Ηinh = ln (t1 / t0) / c

[Wherein ηinh represents logarithmic viscosity (dl / g), t0 represents the flow down time (second) in the solvent, t1 represents the flow down time (second) in the sample solution, and c is the solution) Represents the concentration of the sample (0.1 g / dl). ]

(2) Thermal analysis Differential scanning calorimeter (DSC; manufactured by Mettler, TA-300)
Type 0) for samples that were quenched from the molten state
The measurement was performed at a temperature rising rate of 0 ° C./min.

(3) Heat resistance Small injection molding machine (TK14-1A, manufactured by Tabata Kikai Co., Ltd.)
P type), cylinder temperature 320 ° C, injection pressure 8
00kg / cm ↑ 2, mold temperature 30 ℃ 75 × 15 × 2
A test piece with a size of mm is prepared and a thermomechanical measuring device (TM
A: manufactured by METTLER CORPORATION, TA-3000 type) and evaluated by the heat distortion temperature.

(4) Melt viscosity A melt viscosity was measured at a melting temperature of 280 ° C. and a shear rate of 1000 sec ↑ -1 using a Koka type flow tester.

Synthetic Example 1 1080 g (6.0 mol) of 4-acetoxybenzoic acid and 460 g (2.0 mol) of 6-acetoxy-2-naphthoic acid were added to an internal volume 8 equipped with a stirrer, a distillation column and a nitrogen gas inlet. The reaction system was charged into a 1-liter reactor, and the inside of the reaction system was replaced with nitrogen three times, and then heated to 250 ° C. under a nitrogen stream. While distilling out the acetic acid generated with the progress of the reaction,
The mixture was heated with stirring at 250 ° C. for 3 hours and then at 280 ° C. for 2 hours. After further raising the temperature to 320 ° C., gradually reducing the pressure in the reaction system, and finally stirring at 0.2 mmHg for 1 hour, the produced polyester (this is referred to as the first polyester A) was taken out.

The obtained polyester micro-pieces were heated in a microscope heating device TH-600 manufactured by Linkam Co. under a nitrogen atmosphere at a temperature of 10 ° C./min and observed under a polarizing microscope orthogonal Nicols. However, the light started to be transmitted from around 270 ° C., and the amount of transmitted light further increased as the temperature rose, and even if the temperature finally rose to 350 ° C., an optically anisotropic molten phase was still formed. there were. A sample obtained by rapidly cooling the first polyester A from a molten state was analyzed by DSC at a temperature rising rate of 10 ° C / min. As a result, a glass transition point was not observed and an endothermic peak was observed at 280 ° C. Furthermore the first
The crystallinity of the sample obtained by rapidly cooling the polyester from the molten state was measured by the X-ray wide angle scattering method, and the crystallinity was 40%.
Met. The logarithmic viscosity of the first polyester A in pentafluorophenol measured at 60 ° C. was 5.31 d.
It was 1 / g.

Synthesis Example 2 678 g (2.8 mol) of polyethylene naphthalate having an intrinsic viscosity of 0.65 dl / g measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane and the like, 6-hydroxy-2-naphthoic acid 790 g (4.2 mol), acetic anhydride 510 g (5.0 mol), and acetic acid 504 g (8.4 mol) as a reaction solvent were charged in the same reactor as used in Synthesis Example 1, and the reaction system was charged. After substituting with nitrogen three times, the mixture was stirred and heated under a nitrogen stream under reflux conditions for about 2 hours.
Then, after gradually raising the temperature to 290 ° C. over about 4 hours, the pressure inside the system was gradually reduced, and the reaction was performed at about 30 mmHg for about 2 hours. As a result, about 95% of the theoretical amount of distilled acetic acid and acetic anhydride were obtained. Distilled. Next, the degree of vacuum in the reaction system was further increased, the reaction was carried out at 1 mmHg or less for 1 hour, and then the polyester (this is referred to as the second polyester X) was taken out.

When the second polyester X was observed under a polarizing microscope orthogonal Nicols using the same device as used in Synthesis Example 1, light started to be transmitted from around 150 ° C., and the amount of transmitted light was further increased as the temperature was raised. Then, even if the temperature was finally raised to 350 ° C., the optically anisotropic molten phase was still formed. A sample obtained by rapidly cooling the second polyester X from the molten state was analyzed by DSC at a temperature rising rate of 10 ° C./min. As a result, an endothermic peak was observed at all except that a glass transition point was observed at 88 ° C. There wasn't. Further, the crystallinity of the sample obtained by rapidly cooling the second polyester X from the molten state was measured by the X-ray wide angle scattering method, and as a result, the crystallinity was 8%.
The logarithmic viscosity of the second polyester X in pentafluorophenol measured at 60 ° C. was 0.98 dl / g.

Synthesis Example 3 403 g (2.1 mol) of polyethylene terephthalate having an intrinsic viscosity of 0.70 dl / g measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane in equal weight, 6-
Hydroxy-2-naphthoic acid 790 g (4.2 mol),
97 g (0.7 mol) of p-hydroxybenzoic acid, 602 g (5.9 mol) of acetic anhydride, and 588 g (9.8 mol) of acetic acid as a reaction solvent were charged in the same reactor as used in Synthesis Example 1. After purging the reaction system with nitrogen three times,
Under a nitrogen stream, the mixture was heated with stirring under reflux conditions for about 2 hours. Then, after gradually raising the temperature to 280 ° C over about 4 hours,
The pressure in the system was gradually reduced and the reaction was carried out at about 30 mmHg for about 2 hours. As a result, about 95% of the theoretical amount of acetic acid and acetic anhydride were distilled. Next, the degree of vacuum in the reaction system was further increased, and the reaction was performed at 1 mmHg or less for 1 hour, and then polyester (this is referred to as second polyester Y) was taken out.

When the second polyester Y was observed under a crossed Nicols with a polarizing microscope using the same apparatus as used in Synthesis Example 1, it started to transmit light from around 150 ° C., and the amount of transmitted light further increased with increasing temperature. Then, even if the temperature was finally raised to 350 ° C., the optically anisotropic molten phase was still formed. A sample obtained by rapidly cooling the second polyester Y from the molten state was analyzed by DSC at a temperature rising rate of 10 ° C./min. As a result, an endothermic peak was observed at all except that a glass transition point was observed at 84 ° C. There wasn't. Further, the crystallinity of a sample obtained by rapidly cooling the second polyester from the molten state was measured by the X-ray wide angle scattering method, and as a result, the crystallinity was 10%.
The logarithmic viscosity of the second polyester Y in pentafluorophenol measured at 60 ° C. was 0.92 dl / g.

Examples 1 to 4, Comparative Examples 1 and 2 The first polyester A and the second polyester X were mixed in a predetermined ratio by a twin-screw extruder to obtain compositions. A small injection molding machine (TK14 manufactured by Tabata Kikai Co., Ltd.)
-1AP type), a test piece having a size of 75 × 15 × 2 mm was produced under the conditions of a cylinder temperature of 320 ° C., an injection pressure of 800 kg / cm ↑ 2, and a mold temperature of 30 ° C. The heat resistance evaluation result of the obtained test piece and 280 ° C. of the composition,
Table 1 shows the values of melt viscosity at 1000sec ↑ -1 shear field.
Shown in.

[0046]

[Table 1]

Examples 5-8, Comparative Examples 3 and 4 Using the first polyester A and the second polyester Y, a composition was obtained in the same manner as in Example 1, and a test piece was obtained from the composition. Table 2 shows the result of the evaluation.

[0048]

[Table 2]

[0049]

The thermo-liquid crystal polyester composition provided by the present invention has a low melt viscosity and excellent low-temperature moldability, and the heat resistance and mechanical strength of the molded product obtained from the thermo-liquid crystal polyester composition. Since it has no deterioration in chemical resistance, it can be used as a molding material in various fields.

Claims (1)

[Claims] 1. To 99 to 60 parts by weight of polyester which forms an optically anisotropic molten phase at a temperature of 250 ° C. or higher,
1 to 40 parts by weight of a polyester which forms an optically anisotropic molten phase at a temperature of 00 ° C. or lower are mixed, and the latter polyester is substantially represented by the following formula I: (In the formula, Ar represents a 1,4-phenylene group or a 2,6-naphthylene group.), A structural unit (1) represented by the following formula II: A structural unit (2) represented by the following formula III: And a structural unit (3) represented by the following formula IV Of the structural unit (4), the structural unit (1) and the structural unit (2) are contained in substantially the same number of moles, and the total amount of the structural unit (1) and the structural unit (2) is 15 to 90. Mol%, the total amount of the structural unit (3) and the structural unit (4) is 85 to 10 mol%, and the ratio of the amount of the structural unit (3) to the total amount of the structural unit (3) and the structural unit (4). Is 10 mol% or more, a thermal liquid crystal polyester composition.