JP5274761B2 - Totally aromatic polyester - Google Patents

Abstract

Disclosed is a fully aromatic polyester which is particularly suitably used for multilayer films, multilayer sheets, multilayer blow molded articles and the like, since it is excellent in dimensional stability and heat resistance while having low volume expansion rate. Specifically disclosed is a fully aromatic polyester exhibiting optical anisotropy when melted, which contains structural units introduced from 4-hydroxybenzoic acid, 2,6-naphthalene dicarboxylic acid and hydroquinone at a specific ratio.

Description

  The present invention relates to wholly aromatic polyesters suitably used for films, blow molded articles and the like. More specifically, wholly aromatic polyesters are particularly suitable for use in multilayer films or multilayer sheets, multilayer blow-molded articles, etc., because they have a small volume expansion rate, excellent high dimensional stability, and excellent heat resistance. It is about.

  Liquid crystalline polymers have excellent fluidity, mechanical strength, heat resistance, chemical resistance, and electrical properties in a well-balanced manner, and are therefore widely used as high-performance engineering plastics. It was obtained by molding.

  On the other hand, with the remarkable development of industry in recent years, the use of such liquid crystalline polymers is also becoming more advanced and specialized, and the liquid crystal polymer can be formed efficiently and economically by melt drawing and blow molding. It has been expected to obtain a film or sheet, a hollow molded article, a fiber, or the like that retains excellent physical properties such as dimensional stability, hygroscopicity, and electrical characteristics of the conductive polymer. In recent years, liquid crystalline polymer films have been used for electronic circuit board applications in the field of electrical and electronic materials. However, higher signal speeds, higher pattern density, and higher multi-layers are required, and higher frequency Properties, thickness accuracy, heat resistance, dimensional stability during processing, and multilayering are required. For example, when a liquid crystal polymer film and a metal multilayer body are used for an electronic circuit board, the liquid crystal polymer film and the metal have different thermal expansion coefficients, or the film itself is weak, the multilayer body may be damaged. there were.

  Since the existing liquid crystalline polymer film does not have both dimensional stability and strength, it is difficult to make a multilayer of the liquid crystalline polymer film and the metal. Patent Document 1 proposes a liquid crystalline polymer film having a small volume expansion coefficient due to heat, but the effect is not sufficient.

Moreover, in order to combine dimensional stability and strength, a method of adding various fillers to the liquid crystalline polymer is considered, but the film processability deteriorates, so that it is insufficient as a material for electronic circuit board applications. .
Japanese Patent Laid-Open No. 2004-244452

  The present invention solves the above-mentioned problems of the prior art, has a small volume expansion coefficient, excellent high dimensional stability, and excellent heat resistance, so that a multilayer film or a multilayer sheet, a multilayer blow molded article, etc. An object of the present invention is to provide a wholly aromatic polyester which is particularly preferably used in the invention.

  As a result of intensive research on the provision of wholly aromatic polyesters that achieve the above object and maintain good electrical properties while having a small volume expansion coefficient, high dimensional stability, and excellent heat resistance, The inventors have found that it is effective to select three specific types of raw material monomers and combine the specific amounts to achieve the above object, and the present invention has been completed.

  That is, the present invention includes structural units represented by the following general formulas (I), (II), and (III) as structural components, and the structural unit of (I) is 66 to 75 per 100 mol% of all structural units. It is a wholly aromatic polyester exhibiting optical anisotropy when melted, characterized in that the constituent unit of (II) is 12.5 to 17.0 mol% and the constituent unit of (III) is 12.5 to 17.0 mol% .

(Here, Ar ₁ is 1,4-phenylene, Ar ₂ is 2,6-naphthalene, and Ar ₃ is 1,4-phenylene.)

  The wholly aromatic polyester comprising the specific structural unit obtained in the present invention and anisotropy at the time of melting and its composition are easy to be melt-stretched and blow-molded, processed efficiently and economically, and liquid crystalline polyester It is possible to obtain a film or sheet, fiber and blow-molded product having excellent physical properties.

  In addition, because of its low volume expansion coefficient and excellent dimensional stability, it is particularly suitable for multilayer films or multilayer sheets formed from other polymers and metals, and multilayer blow molded products formed from other polymers. Used for. The other polymer used here is not particularly limited, but polyolefin, particularly high-density polyethylene is suitable.

  In order to embody the structural units (I) to (III), various compounds having ordinary ester forming ability are used. Hereinafter, the raw material compounds necessary for forming the wholly aromatic polyester constituting the present invention will be described in detail step by step.

  The structural unit (I) is introduced from 4-hydroxybenzoic acid and its derivatives.

  The structural unit (II) is introduced from 2,6-naphthalenedicarboxylic acid and its derivatives.

  The structural unit (III) is introduced from hydroquinone and its derivatives.

In the structural unit (III), Ar ₃ needs to be 1,4-phenylene. For example, 4,4′-biphenyl and the like are not preferable because the melting point is remarkably high.

  In the present invention, the copolymerization ratio of each structural unit is important in order to exhibit excellent dimensional stability with a small volume expansion coefficient while maintaining good heat resistance, which is the intended purpose of the present invention. Therefore, in the present invention, the structural units (I) to (III) are included, and the structural unit of (I) is 66 to 75 mol% (preferably 68 to 72 mol%) with respect to 100 mol% of all the structural units. It is necessary that the constituent unit of (II) is 12.5 to 17.0 mol% (preferably 14 to 16 mol%) and the constituent unit of (III) is 12.5 to 17.0 mol% (preferably 14 to 16 mol%). .

  If the structural unit of (I) is less than 66 mol%, it is not preferable because it adversely affects the target dimensional stability (volume expansion coefficient). On the other hand, if it exceeds 75 mol%, the melting point becomes remarkably high, and in some cases, the polymer is solidified in the reactor at the time of production, which makes it impossible to produce a polymer having a desired molecular weight.

  On the other hand, if the constituent unit of (II) is less than 12.5 mol%, the melting point becomes remarkably high, and in some cases, the polymer is solidified in the reactor at the time of production, making it impossible to produce a polymer having a desired molecular weight. On the other hand, if it exceeds 17.0 mol%, the target dimensional stability (volume expansion coefficient) will be adversely affected, which is not preferable.

  On the other hand, if the structural unit of (III) is less than 12.5 mol%, the melting point is remarkably high, and in some cases, the polymer is solidified in the reactor during production, making it impossible to produce a polymer having a desired molecular weight. On the other hand, if it exceeds 17.0 mol%, the target dimensional stability (volume expansion coefficient) will be adversely affected, which is not preferable.

  Incidentally, in the wholly aromatic polyester of the present invention, a small amount of other structural units known in the art can be introduced as long as the object of the present invention is not impaired, but it is preferable that these structural units are practically not contained. .

  The wholly aromatic polyester of the present invention is polymerized using a direct polymerization method or a transesterification method, and a melt polymerization method, a solution polymerization method, a slurry polymerization method or the like is used for the polymerization.

  In the present invention, at the time of polymerization, an acylating agent for the polymerization monomer or a monomer having terminal activated as an acid chloride derivative can be used. Examples of the acylating agent include acid anhydrides such as acetic anhydride, and the amount used is preferably 1.01 to 1.10 times, more preferably 1.02 to 1.05 times the total equivalent weight of the hydroxyl group from the viewpoint of polymerization control.

Various catalysts can be used for these polymerizations, and typical ones include dialkyl tin oxide, diaryl tin oxide, titanium dioxide, alkoxy titanium silicates, titanium alcoholates, alkali and alkaline earth of carboxylic acids. Metal salts, Lewis acid salts such as BF _{3 and} the like. The amount of catalyst used is generally about 0.001 to 1% by weight, particularly about 0.003 to 0.2% by weight, based on the total weight of the monomers.

  Moreover, when performing solution polymerization or slurry polymerization, as a solvent, liquid paraffin, a high heat resistant synthetic oil, an inert mineral oil, etc. are used.

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

  The melt polymerization is performed after the inside of the reaction system has reached a predetermined temperature, and the pressure reduction is started to a predetermined pressure reduction degree. After the torque of the stirrer reaches a predetermined value, an inert gas is introduced, and the polymer is discharged from the reaction system through a normal pressure from a reduced pressure state to a predetermined pressure state.

  The liquid crystalline polymer exhibiting optical anisotropy when melted is an indispensable element in the present invention in order to have both thermal stability and easy processability. Some wholly aromatic polyesters composed of the above structural units do not form an anisotropic molten phase depending on the constituent components and the sequence distribution in the polymer, but the polymer according to the present invention exhibits optical anisotropy when melted. Limited to the fully aromatic polyesters shown.

  The property of melt anisotropy can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, the melting anisotropy can be confirmed by melting a sample placed on a hot stage manufactured by Linkham using an Olympus polarizing microscope and observing it at a magnification of 150 times in a nitrogen atmosphere. The polymer is optically anisotropic and transmits light when inserted between crossed polarizers. If the sample is optically anisotropic, for example, polarized light is transmitted even in a molten stationary liquid state.

The wholly aromatic polyester of the present invention preferably has a melt viscosity of 1 × 10 ⁶ Pa · s or less at a shear rate of 1000 sec ⁻¹ at a temperature higher by 10 ° C. than the melting point. More preferably, it is 1 × 10 ³ Pa · s or less. These melt viscosities are generally realized by having liquid crystallinity.

  The wholly aromatic polyester of the present invention can be formed into a film by melt extrusion molding, inflation molding or the like.

  Melt extrusion molding is a molding method in which a wholly aromatic polyester is melt-kneaded with an extruder and a melt extruded from the slit portion of a T-die is stretched, and a stretched and oriented film can be obtained.

  The setting of the extruder during film formation can be appropriately set according to the skeleton composition ratio of the wholly aromatic polyester. The cylinder temperature of the extruder is preferably 300 to 380 ° C, more preferably 320 to 370 ° C. When the temperature is outside this range, the wholly aromatic polyester tends to be thermally decomposed or film formation tends to be difficult. The slit interval used is preferably 0.1 to 1.0 mm. When the slit interval is larger than 1.0 mm, uneven orientation or the like occurs and the shape of the film tends to deteriorate.

  The drift ratio of the uniaxially oriented film (the value obtained by dividing the cross-sectional area of the T-die slit by the film cross-sectional area in the MD direction) is preferably in the range of 2.0-30. When the drift ratio is less than 2.0, the film strength tends to be insufficient, and when the drift ratio exceeds 30, the smoothness of the film tends to be insufficient.

  Biaxially stretched film is a method in which a melt sheet extruded from a T-die is simultaneously stretched in the longitudinal direction (MD) and both the longitudinal direction and the vertical direction (lateral direction (TD)), or a melt sheet extruded from a T-die Can be obtained by a method of stretching in the MD direction and then stretching in the TD direction. 1.0 or more are preferable and, as for the draw ratio of MD direction and TD direction, 1.5-20 are more preferable. If the draw ratio is out of the above range, it tends to be difficult to obtain a film having a mechanical balance and a uniform thickness.

  Inflation molding is a molding method in which a wholly aromatic polyester is melt-kneaded with an extruder and an inert gas is blown from the inside of a cylindrical sheet melt-extruded from a circular ring die, and a stretched and oriented film can be obtained. .

  The setting of the extruder during film formation can be appropriately set according to the skeleton composition ratio of the wholly aromatic polyester. The cylinder temperature of the extruder is preferably 300 to 380 ° C, more preferably 320 to 370 ° C. When the temperature is outside this range, the wholly aromatic polyester tends to be thermally decomposed or film formation tends to be difficult. The ring-shaped slit interval used is preferably 0.1 to 3.0 mm, and more preferably 0.2 to 1.5 mm. In inflation molding, a draw ratio and a blow ratio are used as equivalent to the draw ratio in the MD direction and the TD direction in the T-die method. The draw ratio corresponds to the draw ratio in the MD direction, preferably 1.5 to 40, and the blow ratio corresponds to the draw ratio in the TD direction, preferably 2.0 to 10. If the setting conditions at the time of inflation film formation are out of the above range, it tends to be difficult to obtain a film having a mechanical balance and a uniform thickness.

  The thickness of the wholly aromatic polyester film obtained by the present invention is preferably 1 to 500 μm, more preferably 5 to 300 μm, from the viewpoints of film formability, mechanical properties and processability.

  The wholly aromatic polyester film obtained by the present invention can be formed into a metal laminate by laminating a metal layer on the surface thereof, or a multilayer laminate of two or more layers of a wholly aromatic polyester film and a metal layer. You can also. Moreover, you may heat-process a metal laminated body as needed for an intensity | strength and adhesive improvement.

  Examples of the metal used include gold, silver, copper, nickel, and aluminum. Copper is preferable for printed wiring board applications, and aluminum is preferable for capacitor applications.

  Next, the wholly aromatic polyester of the present invention can be blended with various fibrous, powdery, and plate-like inorganic and organic fillers within a range that does not affect the film processability.

  Examples of fibrous fillers include glass fibers, asbestos fibers, silica fibers, silica / alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and silicates such as wollastonite. Examples thereof include inorganic fibrous materials such as fibers, magnesium sulfate fibers, aluminum borate fibers, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. A particularly typical fibrous filler is glass fiber. High melting point organic fibrous materials such as polyamide, fluororesin, polyester resin, and acrylic resin can also be used.

  On the other hand, as the granular filler, carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber, glass balloon, glass powder, calcium oxalate, aluminum oxalate, kaolin, clay, diatomaceous earth, wollastonite Oxalates such as, iron oxide, titanium oxide, zinc oxide, antimony trioxide, metal oxides such as alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate Other examples include ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders.

  Examples of the plate-like filler include mica, glass flakes, talc and various metal foils.

  Examples of organic fillers include heat-resistant high-strength synthetic fibers such as aromatic polyester fibers, liquid crystalline polymer fibers, aromatic polyamides, and polyimide fibers.

  These inorganic and organic fillers can be used alone or in combination of two or more. The combined use of the fibrous filler and the granular or plate-like filler is a preferable combination particularly in combination of mechanical strength, dimensional accuracy, electrical properties and the like. The blending amount of the inorganic filler is 120 parts by weight or less, preferably 20 to 80 parts by weight with respect to 100 parts by weight of the wholly aromatic polyester.

  In using these fillers, if necessary, a sizing agent or a surface treatment agent can be used.

  In addition, other thermoplastic resins may be further added to the wholly aromatic polyester of the present invention as long as the purpose of the present invention is not impaired.

  Examples of the thermoplastic resin used in this case are: Polyolefins such as polyethylene and polypropylene, aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate and aromatic diols such as diols, polyacetals (homo or copolymers), polystyrene , Polyvinyl chloride, polyamide, polycarbonate, ABS, polyphenylene oxide, polyphenylene sulfide, fluororesin and the like. These thermoplastic resins can be used in combination of two or more.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, the method of the physical property measurement in an Example is as follows.
[Melting point]
It measured on 20 degreeC / min temperature rising conditions with the differential scanning calorimeter (DSC7 by Perkin-Elmer Co.).
[Melt viscosity]
The measurement was performed with a Capillograph manufactured by Toyo Seiki using an orifice having an inner diameter of 1 mm and a length of 20 mm under the conditions of a measurement temperature of 360 ° C. and a shear rate of 1000 sec ⁻¹ .
[Volume expansion]
The average value of the linear expansion coefficient at 50-100 ° C. in the MD direction and TD direction of the film plane and the ZD direction of the film thickness was calculated with a TMA8310 device manufactured by Rigaku Corporation under a temperature rising condition of 10 ° C./min. The sum of the linear expansion coefficients in the direction was defined as the volume expansion coefficient.

Example 1
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction / outflow line was charged with the following raw material monomer, metal catalyst, and acylating agent, and nitrogen substitution was started.

(I) 227.3 g (70 mol%) of 4-hydroxybenzoic acid
(II) 2,6-Naphthalenedicarboxylic acid 76.2 g (15 mol%)
(III) Hydroquinone 38.8g (15mol%)
Potassium acetate catalyst 22.5mg (30ppm by weight as metal potassium (vs. polymer total weight))
Acetic anhydride 244.8g
After charging the raw materials, the temperature of the reaction system was raised to 140 ° C. and reacted at 140 ° C. for 1 hour. Thereafter, the temperature is further raised to 360 ° C. over 5 hours, and then the pressure is reduced to 10 Torr (that is, 1330 Pa) over 15 minutes. went. After the stirring torque reached a predetermined value, nitrogen was introduced and the pressure was changed from a reduced pressure state to a normal pressure, and the polymer was discharged from the lower part of the polymerization vessel.

  Next, a film was prepared by adjusting the temperature and pressure so that the thickness of the film became 0.05 mm by hot pressing, and the volume expansion coefficient was measured.

Comparative Examples 1-3
Polymerization was carried out in the same manner as in Example 1 except that the type and amount of raw material monomer were as shown in Table 1. These results are shown in Table 1. In Comparative Example 3, the polymer solidified in the reactor at the time of production, and a polymer having a desired molecular weight could not be produced.

Comparative Example 4
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction / outflow line was charged with the following raw material monomer, metal catalyst, and acylating agent, and nitrogen substitution was started.

193.2 g (60 mol%) of 6-hydroxy-2-naphthoic acid
2,6-naphthalenedicarboxylic acid 74.0 g (20 mol%)
6,4'-dihydroxybiphenyl 63.7g (20mol%)
Potassium acetate catalyst 22.5mg (30ppm by weight as metal potassium (vs. polymer total weight))
Acetic anhydride 178.1g
After charging the raw materials, the temperature of the reaction system was raised to 140 ° C. and reacted at 140 ° C. for 1 hour. Thereafter, the temperature is further raised to 350 ° C. over 5 hours, and then the pressure is reduced to 10 Torr (that is, 1330 Pa) over 15 minutes. went. After the stirring torque reached a predetermined value, nitrogen was introduced and the pressure was changed from a reduced pressure state to a normal pressure, and the polymer was discharged from the lower part of the polymerization vessel.

Next, a film was prepared by adjusting the temperature and pressure so that the thickness of the film became 0.05 mm by hot pressing, and the volume expansion coefficient was measured.
The results are shown in Table 1.

(註 in the table)
4-hydroxybenzoic acid NDA; 2,6-naphthalenedicarboxylic acid HQ; hydroquinone HNA; 6-hydroxy-2-naphthoic acid BP; 4,4′-dihydroxybiphenyl

Claims (3)

The structural unit includes structural units represented by the following general formulas (I), (II), and (III), and the structural unit of (I) is 66 to 75 mol% with respect to 100 mol% of all structural units, (II A wholly aromatic polyester exhibiting optical anisotropy when melted, wherein the structural unit is 12.5 to 17.0 mol% and the structural unit (III) is 12.5 to 17.0 mol%.

(Here, Ar ₁ is 1,4-phenylene, Ar ₂ is 2,6-naphthalene, and Ar ₃ is 1,4-phenylene.) A film or sheet formed from the wholly aromatic polyester according to claim 1. A metal laminate obtained by laminating a metal on the film or sheet according to claim 2.