KR102120296B1 - All-aromatic polyester and polyester resin composition - Google Patents

Abstract

[assignment]
Provided are a wholly aromatic polyester having high thermal stability and good hydrolysis resistance, and a polyester resin composition thereof.
[Solution]
60-85 mol% of 6-hydroxy-2-naphthoic acid, 12-40 mol% of 4-hydroxybenzoic acid, 1,4-phenylenedicarboxylic acid, or 4,4'-dihydroxybiphenyl 0.1 The above problem is solved by using an wholly aromatic polyester composed of -3 mol%.

Description

All-aromatic polyester and polyester resin composition

The present invention relates to a wholly aromatic polyester having high thermal stability and good hydrolysis resistance, and a polyester resin composition thereof.

Liquid crystalline polymers represented by liquid crystalline polyester resins are widely used as high-performance engineering plastics because they have excellent balance between fluidity, mechanical strength, heat resistance, chemical resistance, and electrical properties.

Patent Document 1 discloses an improved production method of a thermally stable thermotropic liquid crystalline polyester having a predetermined chain length. In this document, thermal stability is improved by containing a small amount of 1,4-phenylenedicarboxylic acid in the liquid crystalline polyester. However, the thermal stability of such liquid crystalline polyester is not necessarily sufficient.

Patent Document 2 also discloses a method for producing a thermostable thermotropic liquid crystalline polyester having a predetermined chain length. In this document, thermal stability is improved by containing a small amount of 2,6-dihydroxynaphthalene or 4,4'-dihydroxybiphenyl in the liquid crystalline polyester. However, the thermal stability of such liquid crystalline polyester is not necessarily sufficient.

Patent Literature 3 discloses a liquid crystal aromatic polyester for an insulating material and a resin composition thereof. In this document, low dielectric loss tangent is achieved by containing a large amount of 6-hydroxy-2-naphthoic acid in the liquid crystalline aromatic polyester. However, such a liquid crystalline aromatic polyester has a problem of poor thermal stability and a large amount of decomposition gas due to the composition of only highly reactive hydroxycarboxylic acid.

In addition, these liquid crystalline polyesters are not necessarily sufficient in terms of hydrolysis resistance, and when a polyester molded article obtained by molding a polyester resin composition is used in a humid heat environment such as high temperature and high humidity, hydrolysis is promoted. There is a problem that the heat resistance and the mechanical strength are significantly lowered.

[Patent Document 1] Japanese Patent Application Publication No. 60-040127 [Patent Document 2] Japanese Patent Application Publication No. 60-245631 [Patent Document 3] Japanese Patent Application Publication No. 2004-250620

The present invention has been made to solve the above problems, and has an object to provide a wholly aromatic polyester having high thermal stability and good hydrolysis resistance, and a polyester resin composition thereof.

As a result of repeated studies of the present inventors, 6-hydroxy-2-naphthoic acid 60 to 85 mol%, 4-hydroxybenzoic acid 12 to 40 mol%, 1,4-phenylenedicarboxylic acid or 4, By using an wholly aromatic polyester composed of 4'-dihydroxybiphenyl 0.1-3 mol%, it was found that the above problem can be solved, and the present inventors have accomplished the present invention. More specifically, the present invention provides the following.

(1) As an essential component, consists of the following structural units (I), (II), and (III) or (IV),

The content of the structural unit (I) relative to the total structural unit is 60 to 85 mol%,

The content of the structural unit (II) relative to the total structural unit is 12 to 40 mol%,

The content of the structural unit (III) or (IV) relative to the total structural unit is 0.1 to 3 mol%,

The total content of the structural units (I), (II), and (III) or (IV) relative to the total structural units is 100 mol%,

All-aromatic polyester.

(2) The wholly aromatic polyester according to (1), wherein the melt viscosity at a temperature 10 to 30°C higher than the melting point of the wholly aromatic polyester is 1000 Pa·s or less.

(3) The wholly aromatic polyester according to (1) or (2), wherein the melt viscosity at a temperature of 10 to 30°C higher than the melting point of the wholly aromatic polyester is 3 to 500 Pa·s.

(4) The wholly aromatic polyester according to any one of (1) to (3), wherein the melting point is 380°C or lower.

(5) The wholly aromatic polyester according to any one of (1) to (4), wherein the melting point is 250 to 370°C.

(6) The wholly aromatic polyester according to any one of (1) to (5), wherein the heat of crystallization is 2.5 J/g or more.

(7) The wholly aromatic polyester according to any one of (1) to (6), wherein the value of [melting point-crystallization temperature] is 20°C or higher.

(8) The polyester resin composition containing the wholly aromatic polyester according to any one of (1) to (7).

(9) A polyester molded article obtained by molding the wholly aromatic polyester or polyester resin composition according to any one of (1) to (8).

According to the present invention, it is possible to provide an all-aromatic polyester having high thermal stability and good hydrolysis resistance, and a polyester resin composition thereof.

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be carried out by appropriately changing the scope of not impairing the effects of the present invention.

[All-aromatic polyester]

The wholly aromatic polyester according to the present invention, as an essential constituent, consists of the following structural units (I), (II), and (III) or (IV), and The content is 60 to 85 mol%, the content of the structural unit (II) relative to the total structural unit is 12 to 40 mol%, and the content of the structural unit (III) or (IV) relative to the total structural unit is 0.1 to 3 mol %, and the total content of the structural units (I), (II), and (III) or (IV) with respect to the total structural units is 100 mol%.

The structural unit (I) is derived from 6-hydroxy-2-naphthoic acid (hereinafter also referred to as "HNA"). The wholly aromatic polyester of the present invention contains 60 to 85 mol% of the constituent units (I) relative to the total constituent units. When the content of the structural unit (I) is less than 60 mol%, the melting point decreases, and heat resistance is insufficient. When the content of the structural unit (I) exceeds 85 mol%, solidification occurs during polymerization, and a polymer cannot be obtained. The content of the structural unit (I) is preferably 63 to 85 mol%, more preferably 63 to 83 mol%, still more preferably 65 to 83 mol%, even more preferably 65 to 80 mol%, most Preferably it is 68 to 80 mol%.

The structural unit (II) is derived from 4-hydroxybenzoic acid (hereinafter also referred to as "HBA"). The wholly aromatic polyester of this invention contains 12-40 mol% of structural units (II) with respect to all the structural units. When the content of the structural unit (II) is less than 12 mol%, the polymer solidifies in the polymerization vessel at the time of manufacture, and the polymer cannot be discharged. When the content of the structural unit (II) exceeds 40 mol%, the melting point decreases and heat resistance is insufficient. From the viewpoint of melting point and polymerizability, the content of the structural unit (II) is preferably 15 to 40 mol%, more preferably 15 to 35 mol%, still more preferably 18 to 35 mol%, even more preferably 18-30 mol%, most preferably 20-30 mol%.

The structural unit (III) is derived from 1,4-phenylenedicarboxylic acid (hereinafter also referred to as "TA"), and the structural unit (IV) is 4,4'-dihydroxybiphenyl (hereinafter, It is also called "BP".) The wholly aromatic polyester of the present invention contains 0.1 to 3 mol% of constituent units (III) or constituent units (IV) relative to the total constituent units. When the content of the structural unit (III) or the structural unit (IV) is less than 0.1 mol%, thermal stability decreases. When the content of the structural unit (III) or structural unit (IV) exceeds 3 mol%, the molecular weight (melt viscosity) does not increase. From the viewpoint of thermal stability and molecular weight, the content of the structural unit (III) or structural unit (IV) is preferably 0.2 to 2.5 mol%, more preferably 0.2 to 2 mol%, still more preferably 0.3 to 2 mol %, more preferably 0.3 to 1.5 mol%, and most preferably 0.4 to 1.5 mol%.

As described above, the all-aromatic polyester of the present invention contains (I) to (IV), which are specific structural units, in a specific amount with respect to all the structural units, and thus has less generated gas, high thermal stability, and hydrolysis resistance. This is good. The wholly aromatic polyester of the present invention contains 100 mol% of the constituent units (I) to (IV) in total relative to the total constituent units.

Next, the properties of the wholly aromatic polyester will be described. The wholly aromatic polyester of the present invention exhibits optical anisotropy upon melting. The optical anisotropy during melting means that the wholly aromatic polyester of the present invention is a liquid crystal polymer.

In the present invention, the fact that the wholly aromatic polyester is a liquid crystalline polymer is an essential element in that the wholly aromatic polyester has both heat stability and easy processability. The wholly aromatic polyesters composed of the structural units (I) to (IV) may not form an anisotropic molten phase depending on the constituent components and the sequence distribution in the polymer, but the polymers of the present invention are optical upon melting. It is limited to an wholly aromatic polyester showing anisotropy.

The properties of melt anisotropy can be confirmed by a conventional polarization test method using an orthogonal polarizer. More specifically, the confirmation of melt anisotropy can be carried out by melting a sample placed on a hot stage manufactured by Lincam using a polarizing microscope manufactured by Olympus, and observing it under a nitrogen atmosphere at a magnification of 150 times. The liquid crystal polymer is optically anisotropic and transmits light when inserted between orthogonal polarizers. If the sample is optically anisotropic, polarization is transmitted even in the state of, for example, a melt stopper.

Since the nematic liquid crystalline polymer causes a remarkable drop in viscosity at a melting point or higher, it is generally an index of processability to exhibit liquid crystallinity at a melting point or higher. The melting point is preferably as high as possible from the viewpoint of heat resistance, but considering the thermal deterioration during melt processing of the polymer or the heating ability of the molding machine, the preferred criterion is 380°C or lower. The melting point is more preferably 250 to 370°C, more preferably 270 to 370°C, even more preferably 270 to 350°C, and most preferably 290 to 350°C.

The melt viscosity of the wholly aromatic polyester at a temperature of 10 to 30°C higher than the melting point of the wholly aromatic polyester of the present invention and at a shear rate of 1000/sec is preferably 1000 Pa·s or less, more preferably 3 to 500 Pa·s, more preferably 3 to 250 Pa·s. When the melt viscosity is within the above range, the wholly aromatic polyester itself, or the composition containing the wholly aromatic polyester, is easily secured in fluidity during molding, and the filling pressure is unlikely to be excessive. In the present specification, the melt viscosity refers to a melt viscosity measured in accordance with ISO 11443.

The heat of crystallization of the wholly aromatic polyester of the present invention is preferably 2.5 J/g or more, and more preferably 2.5 to 4.4 J/g. When the amount of crystallization heat indicating the crystallization state of the polymer obtained by differential calorimeter measurement is less than 2.5 J/g, crystallinity becomes low and hydrolysis resistance deteriorates. In addition, when the heat of crystallization exceeds 4.4 J/g, toughness is lowered, which is not preferable.

The crystallization calorific value is observed for the endothermic peak temperature (Tm1) observed when the polymer is measured under the elevated temperature condition of 20°C/min from room temperature in the differential calorimeter measurement, and then maintained at (Tm1+40)°C for 2 minutes. Then, it indicates the amount of heat of the exothermic peak obtained from the peak of the exothermic peak temperature observed when measured under a temperature drop condition of 20°C/min.

Further, in the wholly aromatic polyester in the present invention, the value of the melting point minus the crystallization temperature, and the value of [melting point-crystallization temperature] is preferably 20°C or higher, and more preferably 30 to 90°C. When the value of [melting point-crystallization temperature] is within the above range, the wholly aromatic polyester itself, or the composition containing the wholly aromatic polyester, is easily secured in fluidity during molding, and the filling pressure is excessive. Difficult to do

Next, a method for producing the wholly aromatic polyester of the present invention will be described. The wholly aromatic polyester of the present invention is polymerized using a direct polymerization method or a transesterification method. In the polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid phase polymerization method, or a combination of two or more thereof is used, and the melt polymerization method or a combination of the melt polymerization method and the solid phase polymerization method is used. It is preferably used.

In the present invention, when polymerizing, it is possible to use an acylating agent for the polymerized monomer or a terminal activated monomer as an acid chloride derivative. As an acylating agent, fatty acid anhydrides, such as acetic anhydride, etc. are mentioned.

Various catalysts can be used in these polymerizations. Representative examples include potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and tris (2,4-pentanedionate). And metal salt-based catalysts such as cobalt (III), and organic compound-based catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally about 0.001 to 1% by mass, particularly about 0.003 to 0.2% by mass, based on the total mass of the monomer.

[Polyester resin composition]

Various fibrous, granular, and plate-like inorganic and organic fillers can be blended in the above-mentioned all-aromatic polyester of the present invention depending on the purpose of use.

Examples of the inorganic filler to be blended with the polyester resin composition of the present invention are fibrous, granular, and plate-shaped.

As the fibrous inorganic filler, silicate fibers such as glass fiber, milled glass fiber, asbestos fiber, silica fiber, silica/alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, wollastonite And inorganic fibrous substances such as magnesium sulfate fibers, aluminum borate fibers, and metallic fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. A particularly representative fibrous filler is glass fiber.

In addition, the inorganic fillers in the form of carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, silicates such as wollastonite, iron oxide, titanium oxide, and oxidation Metal oxides such as zinc, antimony trioxide, and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, sulfates of metals such as calcium sulfate and barium sulfate, other ferrites, silicon carbide, silicon nitride, boron nitride, and various metal powders. Can be.

Moreover, mica, glass flake, talc, various metal foils etc. are mentioned as plate-shaped inorganic filler.

Examples of the organic filler blended in the polyester resin composition of the present invention include heat-resistant high-strength synthetic fibers such as aromatic polyester fibers, liquid crystal polymer fibers, aromatic polyamides, and polyimide fibers.

These inorganic and organic fillers may be used alone or in combination of two or more. The combination of the fibrous inorganic filler and the granular or plate-like inorganic filler is a preferred combination for combining mechanical strength, dimensional accuracy, and electrical properties. Particularly preferably, glass fibers as the fibrous filler, mica and talc as the plate-like filler, and the blending amount thereof is 120 parts by mass or less, preferably 20 to 80 parts by mass, relative to 100 parts by mass of the wholly aromatic polyester. By combining the glass fibers with mica or talc, the polyester resin composition is particularly remarkable for improvement in heat distortion temperature, mechanical properties, and the like.

In use of these fillers, a bundling agent or a surface treatment agent can be used if necessary.

As described above, the polyester resin composition of the present invention includes the wholly aromatic polyester of the present invention as an essential component and, if necessary, an inorganic or organic filler, but other components as long as it does not impair the effects of the present invention. This can be included. Here, the other components may be any component, and examples thereof include additives such as other resins, antioxidants, stabilizers, pigments, and nucleating agents.

Moreover, the manufacturing method of the polyester resin composition of this invention is not specifically limited, A polyester resin composition can be prepared by a conventionally well-known method.

[Polyester molded products]

The polyester molded article of the present invention is formed by molding the wholly aromatic polyester or polyester resin composition of the present invention. The molding method is not particularly limited, and a general molding method can be adopted. As a general molding method, methods such as injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, and inflation molding can be exemplified.

The polyester molded article formed by molding the wholly aromatic polyester of the present invention is excellent in heat resistance. In addition, the polyester molded article formed by molding the polyester resin composition of the present invention is excellent in heat resistance and, at the same time, contains an inorganic or organic filler as necessary, so that mechanical strength and the like are further improved.

In addition, since the all-aromatic polyester and polyester resin composition of the present invention has excellent moldability, it can be processed into various three-dimensional molded articles, fibers, films, and the like.

Preferred uses of the polyester molded article of the present invention having the above properties include connectors, CPU sockets, relay switch parts, bobbins, actuators, noise reduction filter cases, electronic circuit boards, or heating and fixing rolls for OA devices. have.

[ Example ]

The present invention will be described in more detail by showing examples below, but the present invention is not limited to these examples.

<Example 1>

The following raw material monomer, fatty acid metal salt catalyst, and acylating agent were placed in a polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a reduced pressure/outflow line to initiate nitrogen substitution.

(I) 1.44 mol (76 mol%) of 6-hydroxy-2-naphthoic acid (HNA)

(II) 4-hydroxybenzoic acid 0.44 mol (23.3 mol%) (HBA)

(III) 0.1 mol (0.7 mol%) of terephthalic acid (TA)

Potassium acetate catalyst 22.5mg

196 g of acetic anhydride (1.02 times the total hydroxyl equivalent of HNA and HBA)

After adding the raw materials, the reaction system temperature was raised to 140°C and reacted at 140°C for 2 hours. Subsequently, the temperature was further increased by 4.1 hours to 340°C, and the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes from here, condensing while flowing out acetic acid, excess acetic anhydride, and other low secretions. Sum was performed. After the stirring torque reached a predetermined value, nitrogen was introduced to pressurize through a normal pressure from a reduced pressure state, and the polymer was discharged from the bottom of the polymerization vessel.

<Evaluation>

For the wholly aromatic polyester of Example 1, evaluation of melting point, crystallization temperature, crystallization calorific value, melt viscosity, thermal stability, and hydrolysis resistance was performed by the following method. Table 1 shows the evaluation results.

[Melting point]

Differential Scanning Calorimeter (DSC, manufactured by Perkin Elmer), after observing the endothermic peak temperature (Tm1) observed when all-aromatic polyester is measured at room temperature from room temperature to 20°C/min, at (Tm1+40)°C After holding for 2 minutes, once cooled to room temperature under a temperature drop of 20°C/min, the temperature of the endothermic peak observed when measured under a temperature increase condition of 20°C/min was measured.

[Crystalization temperature]

Differential Scanning Calorimeter (DSC, manufactured by Perkin Elmer), after observing the endothermic peak temperature (Tm1) observed when all-aromatic polyester is measured at room temperature from room temperature to 20°C/min, at (Tm1+40)°C After holding for 2 minutes, the exothermic peak temperature observed when measured under a temperature drop condition of 20° C./minute was measured.

[Crystalization calories]

Differential Scanning Calorimeter (DSC, manufactured by Perkin Elmer), after observing the endothermic peak temperature (Tm1) observed when all-aromatic polyester is measured at room temperature from room temperature to 20°C/min, at (Tm1+40)°C After holding for 2 minutes, the amount of heat of the exothermic peak determined from the peak of the exothermic peak temperature observed when measured under a temperature drop condition of 20° C./minute was measured.

[Melting viscosity]

Using a capillograph manufactured by Toyo Seiki Co., Ltd., at a temperature 10 to 30°C higher than the melting point of the wholly aromatic polyester, using an orifice with an inner diameter of 0.5 mm and a length of 30 mm, at a shear rate of 1000/sec, ISO Based on 11443, the melt viscosity of the wholly aromatic polyester was measured.

[Thermal stability]

Using a differential thermal thermogravimetric measuring device (TG/DTA, manufactured by Seiko Instruments Co., Ltd.), the weight loss when 10 mg of the wholly aromatic polyester was maintained at 370° C. for 30 minutes under a nitrogen flow was measured as the amount of generated gas. Did. When the generated gas amount was less than 15000 ppm, it was judged as good.

[Hydrolysis resistance]

The pre-cooker test was performed for 100 hours under conditions of 121° C., humidity of 100%, and 2 atmospheres with respect to the wholly aromatic polyester, and melt viscosity was measured with respect to the wholly aromatic polyester to obtain a retention rate for the initial value. When the retention rate with respect to the initial value was 90% or more, it was judged as good.

<Example 2>

A polymer was obtained in the same manner as in Example 1 except that the type and input ratio (mol%) of the raw material monomers were as shown in Table 1. The obtained polymer was heated from room temperature to 290°C over 20 minutes in a nitrogen atmosphere, held for 3 hours, and then allowed to cool to obtain a polymer again. In addition, the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results.

<Example 3>

The following raw material monomer, fatty acid metal salt catalyst, and acylating agent were placed in a polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a reduced pressure/outlet line to initiate nitrogen substitution.

(I) 6-hydroxy-2-naphthoic acid 1.51 mol (81 mol%) (HNA)

(II) 4-hydroxybenzoic acid 0.34 mol (18 mol%) (HBA)

(IV) 4,4'-dihydroxybiphenyl 0.02 mol (1 mol%) (BP)

Potassium acetate catalyst 22.5mg

196 g of acetic anhydride (1.02 times the total hydroxyl equivalent of HNA, HBA and BP)

After adding the raw materials, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 2 hours. Next, the temperature was further increased by 4.7 hours to 370°C, and the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes from here, and polycondensation was performed while flowing acetic acid, excess acetic anhydride, and other low secretions. After the stirring torque reached a predetermined value, nitrogen was introduced to pressurize through a normal pressure from a reduced pressure state, and the polymer was discharged from the bottom of the polymerization vessel. In addition, the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results.

<Examples 4 to 8, Comparative Examples 1 to 8>

Polymers were obtained in the same manner as in Example 1, except that the type and input ratio (mole %) of the raw material monomers were as shown in Tables 1 and 2. In addition, the same evaluation as in Example 1 was performed. Table 1 and Table 2 show the evaluation results. In Comparative Example 4, the polymer was solidified in the polymerization vessel at the time of manufacture, so that the polymer could not be discharged.

Claims (9)

As an essential component, it consists of the following structural units (I), (II), and (III) or (IV),
The content of the structural unit (I) relative to the total structural unit is 60 to 85 mol%,
The content of the structural unit (II) relative to the total structural unit is 12 to 40 mol%,
The content of the structural unit (III) or (IV) relative to the total structural unit is 0.1 to 3 mol%,
The total content of the structural units (I), (II), and (III) or (IV) relative to the total structural units is 100 mol%,
All-aromatic polyester.
[Formula 1]

According to claim 1,
A wholly aromatic polyester having a melt viscosity of 1000 Pa·s or less measured in accordance with ISO11443 at a temperature 10 to 30° C. higher than the melting point measured by differential scanning calorimeter of the wholly aromatic polyester, and a shear rate of 1000/sec. The method according to claim 1 or 2,
A wholly aromatic polyester having a melt viscosity of 3 to 500 Pa·s measured in accordance with ISO11443 at a temperature 10 to 30° C. higher than the melting point measured by differential scanning calorimeter of the wholly aromatic polyester, and a shear rate of 1000/sec. The method according to claim 1 or 2,
A wholly aromatic polyester with a melting point of 380°C or lower, as measured by differential scanning calorimeter. The method according to claim 1 or 2,
A wholly aromatic polyester with a melting point of 250 to 370°C as measured by differential scanning calorimeter. The method according to claim 1 or 2,
A wholly aromatic polyester with a crystallization calorific value of at least 2.5 J/g, as measured by a differential scanning calorimeter. The method according to claim 1 or 2,
A wholly aromatic polyester having a value of [melting point measured by differential scanning calorimeter-crystallization temperature measured by differential scanning calorimeter] of 20°C or higher. A polyester resin composition containing the wholly aromatic polyester according to claim 1 or 2. A polyester molded article obtained by molding the wholly aromatic polyester according to claim 1 or 2.