JP4946066B2 - Aromatic liquid crystal polyester and film obtained therefrom - Google Patents

Description

The present invention relates to an aromatic liquid crystal polyester, a film obtained therefrom, and a laminate having the film and a metal layer.

In recent years, aromatic liquid crystal polyesters have been widely used in surface mount electronic components such as connectors due to their excellent low water absorption, heat resistance, thin moldability and the like.
Recently, in the field of electronic components, a film-like aromatic polyester has been demanded.
Therefore, the present inventor has already been derived from a repeating structural unit derived from 2-hydroxy-6-naphthoic acid, a repeating structural unit derived from an aromatic diol, and an aromatic dicarboxylic acid as one that can meet this requirement. Selected from the group consisting of aromatic liquid crystal polyesters substantially composed of repeating structural units (see, for example, Patent Document 1), parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-biphenylcarboxylic acid. An aromatic liquid crystal polyester substantially composed of a repeating structural unit derived from at least one kind of hydroxycarboxylic acid, a repeating structural unit derived from 4,4′-dihydroxybiphenyl, and a repeating structural unit derived from naphthalenedicarboxylic acid ( For example, see Patent Document 2).

JP 2004-196930 A Japanese Patent Laid-Open No. 2004-244452

Thereafter, the inventors further studied the melt extrusion molding using the aromatic liquid crystal polyester as described above, and in some cases, the film was cut during the molding and a continuous film was stably obtained. Encountered the problem of not.
An object of the present invention is to provide an aromatic liquid crystal polyester that can stably provide a continuous film in the solution of the above problem, that is, in melt extrusion molding.

As a result of intensive studies to solve the above problems, the present inventors have found that a continuous film can be stably obtained by setting the weight average molecular weight Mw of the aromatic liquid crystal polyester to a specific molecular weight or more. Various studies were made and the present invention was completed.

That is, the present invention provides aromatic liquid crystal polyesters shown in the following [1] to [4].
[1] The weight average molecular weight Mw in the GPC method is 100,000 or more, and the repeating structural unit is selected from the group consisting of parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid and 4-hydroxy-4′-biphenylcarboxylic acid. 30 to 80 mol% of repeating structural units derived from at least one selected hydroxycarboxylic acid, 35 to 10 mol% of repeating structural units derived from 4,4′-dihydroxybiphenyl, terephthalic acid and / or 2,6 -Aromatic liquid crystal polyester comprising substantially 35 to 10 mol% of repeating structural units derived from dicarboxylic acid selected from naphthalenedicarboxylic acid.
[2] The aromatic liquid crystalline polyester according to the above [1], wherein the hydroxycarboxylic acid is 2-hydroxy-6-naphthoic acid.
[3] The aromatic liquid crystalline polyester according to the above [1] or [2], wherein the dicarboxylic acid is 2,6-naphthalenedicarboxylic acid.
[4] The aromatic liquid crystal polyester according to any one of [1] to [3], wherein the weight average molecular weight Mw in the GPC method is 140000 or more.

Furthermore, this invention provides the aromatic liquid crystal polyester film shown to following [5] and [6], and the laminated body which has this film.
[5] An aromatic liquid crystal polyester film obtained by melt extrusion molding the aromatic liquid crystal polyester of the above [1] to [4].
[6] The aromatic liquid crystalline polyester film of [5], wherein the melt extrusion molding is inflation molding.
[7] A laminate comprising the aromatic liquid crystal polyester film of [5] and [6] above and a metal layer.

By using the aromatic liquid crystal polyester of the present invention, an aromatic liquid crystal polyester film excellent in low water absorption and heat resistance can be obtained continuously and stably, and the present invention is extremely advantageous industrially.

Next, the present invention will be described in detail.
The aromatic liquid crystal polyester of the present invention is a polyester called a thermotropic liquid crystal polymer that exhibits optical anisotropy when melted, and has a weight average molecular weight Mw by the GPC method of 100,000 or more and a repeating structural unit of 30 to 80 mol% of repeating structural units derived from at least one hydroxycarboxylic acid selected from the group consisting of hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-biphenylcarboxylic acid, and 4 35 to 10 mol% of repeating structural units derived from 4,4′-dihydroxybiphenyl and repeating structural units of 35 to 10 derived from at least one dicarboxylic acid selected from the group consisting of terephthalic acid and 2,6-naphthalenedicarboxylic acid It is characterized by substantially consisting of mol%.

The aromatic liquid crystalline polyester of the present invention has a weight average molecular weight Mw in the GPC method of 100,000 or more. The weight average molecular weight Mw is preferably 100,000 to 300,000, more preferably 120,000 to 280000, and particularly preferably 140000 to 260000. That is, the weight average molecular weight Mw is preferably 120,000 or more, and particularly preferably 140000 or more. Thus, it is preferable that the weight average molecular weight Mw is large because a film can be obtained more stably in melt extrusion molding. On the other hand, the upper limit value of the weight average molecular weight Mw is preferably 300,000 or less, more preferably 280000 or less, and particularly preferably 260000 or less. Thus, when the weight average molecular weight Mw is 300000 or less, the processing temperature in melt extrusion molding can be lowered, which is preferable.

Here, the GPC analysis of the present invention will be described.
The weight average molecular weight Mw is usually obtained by dissolving an aromatic liquid crystal polyester in 3,5-bis (trifluoromethyl) phenol at a temperature range of about 60 to 80 ° C. to a concentration of about 1 mg / ml. It is to be obtained under conditions.
Column: 3 TSKgel GMH _HR- M (S) in series
(Tosoh, 13μm each, 7.8mm ID × 30cm)
Developing solvent: 3,5-bis (trifluoromethyl) phenol Flow rate: 500 μl / min
Temperature: 80 ° C
The general-purpose calibration curve (hereinafter referred to as a universal calibration curve) for measuring the weight average molecular weight Mw uses polystyrene with a known molecular weight, and uses the above GPC conditions to perform both differential refractive index (RI) detection and viscosity detection. It can be created from the result. Subsequently, the liquid crystal polyester can be measured under the same GPC conditions, and can be calculated based on the general-purpose calibration curve from the obtained elution time. Such a universal calibration curve can be easily prepared based on literature (Sadao Mori, “Size Exclusion Chromatography—High Performance Liquid Chromatography of Polymers”, 67-69, 1991, Kyoritsu Shuppan). is there. As polystyrene having a known molecular weight, those generally marketed as GPC standard products (for example, those manufactured by Tosoh Corporation, Showa Denko Corporation, etc.) can be used.

In the aromatic liquid crystal polyester of the present invention, the repeating structural unit derived from hydroxycarboxylic acid is in the range of 30 to 80 mol%, as described above, preferably 35 to 75 mol%, more preferably 40. It is -70 mol%, Most preferably, it is 40-60 mol%. If the repeating structural unit derived from hydroxycarboxylic acid is low, it tends to be difficult to exhibit liquid crystallinity, while if too large, the film processability tends to be reduced.

The repeating structural unit derived from hydroxycarboxylic acid is derived from at least one selected from the group consisting of parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, and 4-hydroxy-4′-biphenylcarboxylic acid. Repeating structural units are used. Among them, it is preferable to include a repeating structural unit derived from 2-hydroxy-6-naphthoic acid, and in particular, the repeating structural units derived from hydroxycarboxylic acid are all repeating structural units derived from 2-hydroxy-6-naphthoic acid. Preferably there is. This is preferable because an aromatic liquid crystal polyester having a lower dielectric loss at a high frequency can be obtained.
Furthermore, the repeating structural unit derived from the hydroxycarboxylic acid may have a substituent, and examples of the substituent include a halogen atom, an alkyl group, and an aryl group.

The repeating structural unit derived from 4,4′-dihydroxybiphenyl may also have a substituent, and examples of the substituent include a halogen atom, an alkyl group, and an aryl group.
The repeating structural unit derived from dicarboxylic acid is a repeating structural unit derived from dicarboxylic acid selected from terephthalic acid and / or 2,6-naphthalenedicarboxylic acid, and a structure derived from 2,6-naphthalenedicarboxylic acid. It is more preferable when a unit is included, and it is particularly preferable that the repeating structural unit derived from all dicarboxylic acids is a structural unit derived from 2,6-naphthalenedicarboxylic acid.
Thus, when the repeating structural unit derived from dicarboxylic acid is a structural unit derived from 2,6-naphthalenedicarboxylic acid, the thermal stability of the aromatic polyester is further improved, while derived from dicarboxylic acid. When the repeating structural unit replaces a part of the repeating structural unit derived from dicarboxylic acid derived from 2,6-naphthalenedicarboxylic acid with the repeating structural unit derived from terephthalic acid, the processing temperature of the resulting aromatic polyester is lowered. Therefore, in order to obtain a higher heat-resistant aromatic polyester film, there is a need for more simple processing even if the number of repeating structural units derived from 2,6-naphthalenedicarboxylic acid is increased and the heat resistance is lowered. It is preferable to include a repeating structural unit derived from an acid. Thus, the balance between heat resistance and processability can be controlled by the repeating structural unit derived from dicarboxylic acid.
The repeating structural unit derived from the dicarboxylic acid may have a substituent, and examples of the substituent include a halogen atom, an alkyl group, and an aryl group.

The repeating structural unit derived from dicarboxylic acid and the repeating structural unit derived from 4,4′-dihydroxybiphenyl are each selected from the range of 35 to 10 mol% in the aromatic liquid crystal polyester, but preferably 32. 0.5 to 12.5 mol%, more preferably 30 to 15 mol%. Furthermore, the repeating structural unit derived from dicarboxylic acid and the repeating structural unit derived from 4,4'-dihydroxybiphenyl are preferably in the range of 85/100 to 100/85 as a molar ratio.

In the present invention, each repeating structural unit may have a substituent such as a halogen atom, an alkyl group, or an aryl group as described above. In this case, examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group include C1-C10 alkyl groups represented by a methyl group, an ethyl group, a propyl group, a butyl group, and the like, and examples of the aryl group include a phenyl group and a naphthyl group. And an aryl group having 6 to 20 carbon atoms.

Next, a method for producing an aromatic liquid crystal polyester having a weight average molecular weight Mw of 100,000 or more according to the present invention will be described.
As the production method, for example, a monomer corresponding to the above repeating structural unit is used, and after hydroxylation of the hydroxyl group among them, melt polycondensation is performed by deacylation polycondensation by a known method. A low molecular weight aromatic liquid crystal polyester (hereinafter abbreviated as “prepolymer”) is obtained (see JP 2002-146003 A), and this prepolymer is then powdered and solid-phase polymerized by heating. An aromatic liquid crystal polyester having a desired molecular weight can be obtained by appropriately controlling the polymerization temperature and polymerization time in the solid phase polymerization to increase the molecular weight. In addition, the repeating structural unit derived from the above hydroxycarboxylic acid, the repeating structural unit derived from 4,4′-dihydroxybiphenyl, the repeating structural unit derived from dicarboxylic acid, and the molar ratio of the monomer corresponding to the repeating structural unit, respectively. It can be easily controlled by the charging ratio.

Here, in order to make the prepolymer into powder, for example, the prepolymer may be cooled and solidified and then pulverized. The particle diameter of the powder is usually about 0.05 to 3 mm. It is preferable that the thickness is about 0.05 to 1.5 mm because the degree of polymerization of the aromatic liquid crystal polyester is increased, and if it is about 0.1 to 1.0 mm, sintering between powder particles occurs. Since the high molecular weight of the aromatic liquid crystal polyester is promoted without any problem, it is more preferable.

Next, preferable polymerization conditions in the solid phase polymerization will be described.
Heating in solid phase polymerization is usually performed while increasing the temperature, for example, from room temperature to a temperature that is 20 ° C. or more lower than the flow initiation temperature of the prepolymer. The temperature raising time at this time is not particularly limited, but is preferably within 1 hour from the viewpoint of shortening the reaction time. Moreover, the flow start temperature of the prepolymer can be determined in advance using a flow tester.
Next, the temperature is raised from a temperature 20 ° C. or more lower than the flow start temperature of the prepolymer to a temperature of 300 to 315 ° C. at a rate of temperature increase of 0.3 ° C./min or less. The temperature rising rate is preferably 0.1 to 0.15 ° C./min. A heating rate of 0.3 ° C./min or less is preferable because sintering between the particles of the powder hardly occurs, so that it becomes easy to produce a high molecular weight aromatic liquid crystal polyester.

Subsequently, it is held at a temperature range of 300 to 315 ° C. for 1 to 30 hours. This makes it possible to remove low boiling components remaining in the prepolymer. The holding time is preferably 1 to 20 hours, more preferably 1 to 4 hours.

Next, the temperature is further increased to a range of 320 to 400 ° C. at a temperature increase rate of 0.3 ° C./min or less. The heating rate is preferably 0.1 to 0.15 ° C./min. A heating rate of 0.3 ° C./min or less is preferable because sintering between powder particles is less likely to occur, and thus it is easy to produce a high molecular weight aromatic liquid crystal polyester.

As a final step, an aromatic liquid crystal polyester having a desired molecular weight can be obtained by increasing the molecular weight of the aromatic liquid crystal polyester by maintaining the temperature in the range of 320 to 400 ° C. for 30 minutes to 30 hours. The polymerization time in the final step is preferably 30 minutes to 20 hours.
Thus, high molecular weight progresses by holding at a higher temperature for a longer time, but in particular, from the viewpoint of the thermal stability of the obtained aromatic liquid crystal polyester, it is held at 320 to 350 ° C. for 30 minutes to 30 hours. It is preferable to maintain the temperature at 320 to 340 ° C. for 30 minutes to 20 hours. Furthermore, the reaction time can be determined while sampling polyester during the reaction and confirming the weight average molecular weight Mw by the GPC method. In addition, it is possible to determine the polymerization conditions in the final step by conducting preliminary polymerization experiments with varying reaction temperatures and reaction times.
Thus, the aromatic liquid crystal polyester of the present invention having a weight average molecular weight Mw by the GPC method of 100,000 or more can be obtained.

Next, an aromatic liquid crystal polyester film obtained by molding the aromatic liquid crystal polyester of the present invention will be described.
In forming the aromatic liquid crystalline polyester of the present invention into a film, a melt extrusion molding method is employed. As a specific method, for example, an aromatic liquid crystalline polyester is melt-kneaded with an extruder, and a molten resin extruded through a T-die is wound up while being stretched in the direction of the winder (longitudinal direction) to obtain a uniaxially oriented film. Examples thereof include a method of obtaining a biaxially stretched film, which will be described later, and a method of obtaining an inflation film by forming a melt sheet extruded from a cylindrical die by an inflation method.
In particular, the inflation method is preferable from the viewpoint of industrially improving productivity.

Here, as the set temperature of the extruder according to the production of the uniaxially oriented film, an optimum set temperature can be appropriately selected according to the monomer composition of the aromatic liquid crystal polyester, but it is usually about 280 to 400 ° C, preferably 320 to 380 ° C. Degree. When the set temperature of the cylinder is about 280 to 400 ° C., thermal decomposition of the aromatic liquid crystal polyester can be suppressed, and film formation becomes easy.
The slit interval of the T die is usually about 0.1 to 2 mm, and the draft ratio of the uniaxially oriented film is usually in the range of about 1.1 to 45. The draft ratio here refers to a value obtained by dividing the sectional area of the T-die slit by the film sectional area in the longitudinal direction. When the draft ratio is 1.1 or more, the film strength tends to be improved, and when the draft ratio is 45 or less, the surface smoothness of the film tends to be excellent. The draft ratio can be adjusted by the setting conditions of the extruder, the winding speed, and the like.

When producing a biaxially stretched film, the setting conditions of the extruder similar to the uniaxially oriented film, that is, the set temperature of the cylinder is usually about 280 to 400 ° C, preferably about 320 to 380 ° C. The slit spacing is usually melt extrusion within a range of 0.1 to 2 mm.
As the biaxial stretching method, the melt sheet extruded from the T die is stretched simultaneously in the longitudinal direction and the longitudinal direction (transverse direction), the melt sheet extruded from the T die is first stretched in the longitudinal direction, Next, a method of sequential stretching in which the stretched sheet is stretched in the transverse direction from the tenter at a high temperature of 100 to 400 ° C. in the same process, and the like.
The stretching ratio of the biaxially stretched film is preferably in the range of 1.1 to 20 times in the longitudinal direction and 1.1 to 20 times in the transverse direction. When the stretch ratio is within the above range, the obtained film is excellent in strength and it becomes easy to obtain a film having a uniform thickness.

Also, the inflation film is melted by supplying aromatic liquid crystal polyester to a melt-kneading extruder equipped with a die having an annular slit, and maintaining the cylinder set temperature at about 280 to 400 ° C., preferably about 320 to 380 ° C. Kneading is performed to extrude the cylindrical aromatic polyester film upward or downward from the annular slit of the extruder. The interval between the annular slits is usually 0.1 to 5 mm, preferably 0.2 to 2 mm, and the diameter of the annular slit is usually 20 to 1000 mm, preferably 25 to 600 mm.

A draft is applied in the longitudinal direction (MD) to the melt-extruded tubular molten resin film, and air or an inert gas such as nitrogen gas is blown from the inside of the tubular melt-resin film so that the longitudinal direction The film is stretched and stretched in the transverse direction (TD) at right angles.
Here, the blow-up ratio (the ratio of the final tube diameter to the initial diameter) is usually 1.5 to 10.
The MD draw ratio is usually from 1.5 to 40, and within this range, a high-strength aromatic liquid crystal polyester film having a uniform thickness and no wrinkles can be obtained.
The film stretched and stretched is air-cooled or water-cooled, and then passed through a nip roll and taken off.
In the inflation film formation, it is preferable to select conditions such that the cylindrical melt film expands to a smooth surface with a uniform thickness according to the composition of the aromatic liquid crystal polyester.

The thickness of the aromatic liquid crystal polyester film of the present invention obtained as described above is usually 0.5 to 500 μm from the viewpoint of film forming properties and mechanical properties, and 1 to 300 μm from the viewpoint of handleability. It is preferable.

In the aromatic liquid crystal polyester film of the present invention, a laminate can also be produced by laminating a metal layer. In laminating the metal layer, the surface of the aromatic liquid crystal polyester film on which the metal layer is laminated may be subjected to corona discharge treatment, ultraviolet irradiation treatment, or plasma treatment in order to increase the adhesive force.
Here, as a method of laminating a metal layer on the aromatic liquid crystal polyester film of the present invention,
For example,
(1) A method of attaching an aromatic liquid crystal polyester film to a metal foil by thermocompression bonding,
(2) A method of attaching an aromatic liquid crystal polyester film and a metal foil with an adhesive,
(3) A method of forming a metal layer on the aromatic liquid crystal polyester film by vapor deposition, and the like.

Among these, the laminating method (1) is a method of pressure bonding with a metal foil near the flow start temperature of the aromatic liquid crystal polyester film using a press or a heating roll, and is recommended because it can be easily carried out.
Examples of the adhesive used in the laminating method (2) include a hot melt adhesive and a polyurethane adhesive. Among them, an epoxy group-containing ethylene copolymer is preferably used as an adhesive.
Examples of the lamination method (3) include an ion beam sputtering method, a high frequency sputtering method, a direct current magnetron sputtering method, and a glow discharge method. Among these, a high frequency sputtering method is preferably used.
Examples of the metal used for laminating the metal layers include gold, silver, copper, nickel, and aluminum. Copper is preferred for tab tape and printed wiring board applications, and aluminum is preferred for capacitor applications.

Examples of the structure of the laminate thus obtained include a two-layer structure of an aromatic liquid crystal polyester film and a metal layer, a three-layer structure in which a metal layer is laminated on both surfaces of an aromatic liquid crystal polyester film, and an aromatic liquid crystal polyester. Examples include a multilayer structure in which films and metal layers are alternately laminated. The laminate may be heat-treated as necessary for the purpose of developing high strength.

Moreover, the aromatic liquid-crystal polyester film of this invention can also contain a filler, an additive, etc. in the range which does not impair the objective of this invention. Here, examples of the filler include epoxy resin powder, melamine resin powder, urea resin powder, benzoguanamine resin powder, polyester resin powder, organic filler such as styrene resin, silica, alumina, titanium oxide, zirconia, kaolin, calcium carbonate. And inorganic fillers such as calcium phosphate.
Examples of the additive include a coupling agent, an anti-settling agent, an ultraviolet absorber, and a heat stabilizer.
These fillers and additives can be easily contained in a film by mixing them together when the aromatic liquid crystal polyester is melt-kneaded with an extruder.

In addition, the aromatic liquid crystal polyester film of the present invention is a polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenyl ether and its modified product, One kind or two or more kinds of thermoplastic resins such as etherimide and elastomers such as a copolymer of glycidyl methacrylate and polyethylene may be contained.
In addition, other thermoplastic resins or elastomers can be contained in the film in the same manner as in the method relating to the filler and additive.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this.

The flow start temperature was measured by the following method.
Using a flow tester (manufactured by Shimadzu Corporation, “CFT-500 type”), a sample amount of about 2 g is filled into a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm. The temperature at which the melt viscosity is 4800 Pa · s (48000 poise) when the aromatic polyester is extruded from the nozzle under a load of 9.8 MPa (100 kg / cm 2) at a heating rate of 4 ° C./min is defined as the flow start temperature. .

The weight average molecular weight Mw was measured by the following method.
A sample bottle containing 10 mg of sample is added with 3,5-bis (trifluoromethyl) phenol as a solvent to a concentration of 1 mg / ml, and the sample is dissolved in a temperature range of 60 to 80 ° C .. After dissolution of the sample, the solution was filtered through a 0.45 μm filter. For the filtered sample, standard polystyrene was used by the GPC method, a universal calibration curve was created from both results using both RI and viscosity detectors, and the weight average molecular weight Mw was calculated. The GPC conditions are as follows.
Column: TSKgel GMH _HR -M (S) (Tosoh, 13 μm each,
(7.8 mm ID × 30 cm) 3 in series Developing solvent: 3,5-bis (trifluoromethyl) phenol Flow rate: 500 μl / min
Temperature: 80 ° C

The film processability was evaluated by the following method.
Aromatic polyester powder is melted in a uniaxial extruder (screw diameter 50 mm), and a draft ratio is 4 from a T die (lip length 300 mm, lip clearance 1 mm, die temperature 360 ° C.) at the tip of the extruder. Extruded into a film and cooled to produce an aromatic liquid crystalline polyester film having a thickness of 250 μm. In this film processing step, when the melt tension is excellent and a film is continuously obtained for 1 hour or more, a film is obtained, but the film cannot be continuously obtained because the melt tension is low during film processing. △ was marked △.

The film physical properties were evaluated by the following methods.
The dielectric constant and dielectric loss were measured with an impedance material analyzer manufactured by Hewlett-Packard Co., Ltd.
As for the foam resistance (blister) of the film, the film was immersed in H60A solder (tin 60%, lead 40) at 280 ° C. for 120 seconds, and the case where no foaming was observed was evaluated as “good”.

Synthesis example 1
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 987.95 g (5.25 mol) of 2-hydroxy-6-naphthoic acid, 4,4′-dihydroxybiphenyl 486. 47 g (2.612 mol, 0.237 mol excess), 2,6-naphthalenedicarboxylic acid 513.45 g (2.375 mol), acetic anhydride 1174.04 (11.5 mol) and 1-methylimidazole 0 as catalyst 194 g was added, and the mixture was stirred at room temperature for 15 minutes, and then heated while stirring. When the internal temperature reaches 145 ° C,
The mixture was stirred for 1 hour while maintaining the same temperature, and 5.83 g of 1-methylimidazole as a catalyst was further added.

Next, the temperature was raised from 145 ° C. to 310 ° C. over 3 hours and 30 minutes while distilling off distilling by-product acetic acid and unreacted acetic anhydride. The mixture was kept at the same temperature for 2 hours to obtain an aromatic polyester. The obtained aromatic polyester was cooled to room temperature and pulverized with a pulverizer to obtain an aromatic polyester powder having a particle size of about 0.1 to 1 mm.
It was 273 degreeC when the flow start temperature was measured about this aromatic liquid-crystal polyester powder using the flow tester.

Synthesis example 2
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 564.54 g (3 mol) of 2-hydroxy-6-naphthoic acid, 279.32 g of 4,4′-dihydroxybiphenyl ( 1.5 mol), 3,6-naphthalenedicarboxylic acid 324.49 g (1.5 mol), acetic anhydride 704.42 (6.9 mol) and 0.117 g of 1-methylimidazole as a catalyst were added at room temperature. After stirring for 15 minutes, the temperature was raised while stirring. When the internal temperature reached 145 ° C., the mixture was stirred for 1 hour while maintaining the same temperature, and 1.170 g of 1-methylimidazole as a catalyst was further added.
Next, the temperature was raised from 145 ° C. to 310 ° C. over 3 hours while distilling off distilling by-product acetic acid and unreacted acetic anhydride. The mixture was kept at the same temperature for 2 hours and 30 minutes to obtain an aromatic liquid crystal polyester. The obtained aromatic liquid crystal polyester was cooled to room temperature and pulverized with a pulverizer to obtain an aromatic liquid crystal polyester powder having a particle size of about 0.1 to 1 mm.

Example 1
The powder obtained in Synthesis Example 1 was heated from 25 ° C. to 250 ° C. over 1 hour, heated from the same temperature to 310 ° C. over 10 hours, and then kept at that temperature for 4 hours. Next, the temperature was raised from 310 ° C. to 345 ° C. over 10 hours, and then kept at that temperature for 12 hours for solid phase polymerization. Thereafter, the powder after solid-phase polymerization was cooled, and the flow-starting temperature of the cooled aromatic liquid crystal polyester powder was measured using a flow tester. Table 1 shows the film processability evaluation results and the physical property evaluation results of the obtained film.

Example 2
In Example 1, the temperature was raised from 310 ° C. to 345 ° C. over 10 hours and then kept at the same temperature for 12 hours, instead of being heated from 310 ° C. to 335 ° C. over 10 hours and then kept at the same temperature for 12 hours. Except for the above, an aromatic liquid crystal polyester powder was obtained according to Synthesis Example 1. The flow starting temperature was 365 ° C. Table 1 shows the film processability evaluation results and the physical property evaluation results of the obtained film.

Example 3
In Example 1, the temperature was raised from 310 ° C. to 345 ° C. over 10 hours and then kept at the same temperature for 12 hours, instead of being heated from 310 ° C. to 330 ° C. over 10 hours and then kept at the same temperature for 12 hours. Except for the above, an aromatic liquid crystal polyester powder was obtained according to Synthesis Example 1. The flow starting temperature was 357 ° C. Table 1 shows the film processability evaluation results and the physical property evaluation results of the obtained film.

Comparative Example 1
The powder obtained in Synthesis Example 1 was heated from 25 ° C. to 250 ° C. over 1 hour, then heated from the same temperature to 325 ° C. over 10 hours, and then kept at that temperature for 12 hours to solid phase polymerization. I let you. Thereafter, the powder after solid phase polymerization was cooled to obtain an aromatic liquid crystal polyester powder. The flow starting temperature was 349 ° C. Table 1 shows the film processability evaluation results and the physical property evaluation results of the obtained film.

Comparative Example 2
The powder obtained in Synthesis Example 2 was heated from 25 ° C. to 250 ° C. over 1 hour, then heated from the same temperature to 320 ° C. over 8 hours, and then kept at that temperature for 5 hours to solid phase polymerization. I let you. Thereafter, the powder after solid phase polymerization was cooled to obtain an aromatic liquid crystal polyester powder. The flow starting temperature was 326 ° C. Table 1 shows the film processability evaluation results and the physical property evaluation results of the obtained film.

Claims (5)

The weight average molecular weight Mw in the GPC method is 100,000 or more, and the repeating structural unit is derived from 30 to 80 mol% of the repeating structural unit derived from 2 -hydroxy-6-naphthoic acid and 4,4′-dihydroxybiphenyl. repeating structural units 35 to 10 mol%, 2, repeating structural units 35 to 10 mol% or only Rana aromatic liquid crystalline polyester, characterized in Rukoto derived from 6-naphthalene dicarboxylic acid. The aromatic liquid crystal polyester according to claim 1, wherein the weight average molecular weight Mw in the GPC method is 140000 or more. An aromatic liquid crystal polyester film obtained by melt-extrusion molding the aromatic liquid crystal polyester according to claim 1 or 2 . The aromatic liquid crystal polyester film according to claim 3, wherein the melt extrusion molding is inflation molding. A laminate comprising the aromatic liquid crystal polyester film according to claim 3 or 4 and a metal layer.